protection design guidelines and references...rev 10 – 15 sep 2010 1 protection design guidelines...

Rev 10 – 15 Sep 2010

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Protection design guidelines and references – Compiled by E van Straten / P Gerber – Rev 10 – 15 Sep 2010

The purpose of this document serves as a guide for the design of protection schemes for the Nelson Mandela Bay Municipality. Any deviation from or changes to these guidelines must be ratified by the Technical Manager: Protection. Contents Par. Title .1 Terminology 1.2 DC Supply 1.3 AC Supply 1.4 Circuit Breaker Trip Coils 1.5 Trip Circuit Supervision 1.6 Local / Remote control of Circuit Breakers 1.7 Anti-pump timer 1.8 Test Blocks 1.9 Terminals 1.10 Wiring 1.11 Current Transformers 1.12 Voltage Transformers 1.13 Protection Relays 1.14 Trip Isolation Links 1.15 Spring Discharge Circuit 1.16 Luminous Indicators 1.17 Voltmeters and Voltage Transducers 1.18 Ammeters and Current Transducers 1.19 Labels 1.20 Drawings 1.21 General Substation Layout Numbering 1.22 SCADA 1.23 Transformer Alarms and Indications 1.24 Isolator auxiliary contacts 1.25 Breaker Fail Protection A. Typical Plant Layouts 2. Transformer Protection – Type 1 3. Transformer Protection – Type 2A/B 4. Transformer Feeder Protection – Type 1

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Par. Title Page 5. Transformer Feeder Protection – Type 2 6. Feeder Protection – Type 1A 7. Feeder Protection – Type 1B 8. Feeder Protection – Type 1C 9. Feeder Protection – Type 1D 10. Feeder Protection – Type 1E 11. Feeder Protection – Type 2 12. Feeder Protection – Type 3 13. Buscoupler/Bussection – Type 1 14. Buscoupler/Bussection – Type 2 15. Buscoupler/Bussection – Type 3 16. Arc Detection Protection 17. Buszone Protection 18. Remote Tap Change Control Panel

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1. General 1.1 Terminology The following terminology shall be used on technical drawings: Relay panel A metal enclosed panel that contains control, measuring, indicating,

alarm, protective and regulating equipment associated with outdoor switchgear.

Relay chamber

A metal enclosed panel that contains control, measuring, indicating, alarm, protective and regulating equipment associated with metal-clad switchgear.

Yard marshalling kiosk

An outdoor metal enclosed panel that is used as a junction or marshalling point associated with an outdoor bay.

Transformer marshalling kiosk

An outdoor metal enclosed panel that is used as a junction or marshalling point associated with a power transformer.

Control room The brick building that houses the relay panels and/or metal-clad switchgear.

1.2 DC Supply See figures 1.1 (MV panels) and 1.2 (HV Relay panels) for a general layout of the DC supply. The DC supply shall be fed from a DC Distribution board via double pole MCB’s. Each MV switchboard shall be fed with a single DC supply (minimum 4 mm²) from each of the BTU’s in the control room. Each HV relay panel shall have its own DC supply cable (One for J1, J2 and another for J3, J4). Should there be no separate BTU for the back-up protection and control DC supply (J3, J4), the same shall be jumpered from the main protection supply (J1, J2) at the rear terminals (MV switchboard) or the external access terminals (relay panel board). The DC supply to the MV board shall be looped externally from panel to panel. Each MV switchboard or HV relay panel shall be supplied from a unique double pole MCB on the DC Distribution board. Each Tap Change panel shall have its own DC supply. Each panel shall be equipped with appropriately rated D.C double-pole miniature circuit breakers, protecting the following segregated circuits: Main Trip Circuit Back up Trip Circuit Closing Circuit Spring Rewind Circuit (For a D.C spring rewind motor) Indication Circuit

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SCADA Control Circuit The Main Trip supply shall be labelled J1 and J2. All other supplies shall be labelled J3 and J4. The closing circuit shall be a sub circuit of the tripping circuit unless the closing circuit is interlocked by a trip circuit supervision contact. Figure 1.1 – MV Panels

J1 J2

DC Distribution Board

Panel 1

Main Trip

Back Up Trip

Indication SCADA Control

Spring Rewind

Close

Panel 2

J1

J2

J3

J4

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J1

1.3 AC Supply The AC supply shall be fed from an AC Distribution board via a double pole circuit breaker. The AC supply shall be looped from panel to panel similar to that of the DC supply on MV panels. Each MV switchboard or set of HV relay panels shall be supplied from a unique double pole MCB on the AC Distribution board. Each Tap Change panel shall have its own AC supply. Each panel shall be equipped with appropriately rated A.C double-pole miniature circuit breakers, protecting the following segregated circuits:

Spring Rewind Circuit (For an A.C spring rewind motor) Panel Light and Heater Circuit

J3 J3

J1

J1 J2

DC Distribution Board

Main Trip

Back Up Trip

Indication SCADA Control

Spring Rewind

Close

J4

J2

Panel 1

J4

Panel 2

Fig 1.2 – HV Control Panels

J2

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The supply shall be labelled H1 and H2. See figure 1.3 for a general layout of the AC supply. Figure 1.3

H1

H2

Panel 1 Panel 2

AC Distribution Board

Panel Light, Heater

Spring Rewind

Outdoor Equipment

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1.4 Circuit Breaker Trip Coils 1.4.1 MV Switchgear All MV circuit breakers shall have two trip coils, termed main trip coil and back up trip coil respectively. 1.4.2 HV Switchgear All HV circuit breakers shall have two trip coils, termed main trip coil and back up trip coil respectively. 1.5 Trip Circuit Supervision 1.5.1 MV Switchgear If trip circuit supervision functionality is available on the protection relays that reside on the MV panel, it shall be utilised to supervise both the main and back up trip coils. Relays energised from the main trip circuit shall be used to supervise the main trip coil and relays energised from the back up trip circuit shall be used to supervise the back up trip coil. Trip circuit supervision shall monitor the trip circuit while the circuit breaker is in the open and closed position. It shall also be wired so as to monitor the status of the circuit breaker auxiliary contacts. A trip circuit supervision normally open contact for each trip circuit shall be wired into the closing circuit to prevent closing in the event of a trip circuit D.C supply fail or a discontinuity in the any trip circuit. It shall also be wired so as not to signal when the circuit breaker is racked into the circuit or busbar earth position and the breaker is the open position. This will then allow electrical closing of the breaker when the circuit breaker is racked into the circuit or busbar earth position. 1.5.1.1 Back / Front Busbar type switchgear A typical example of a trip circuit supervision circuit applied on an ABB type breaker is shown in Figure 1.4.

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Figure 1.4 1.5.1.2 Top / Bottom Busbar type switchgear A typical example of a trip circuit supervision circuit applied on an Alstom type breaker is shown in Figure 1.5.

Back Busbar Service Position

Back Busbar Service Position

Front Busbar Earth Position

Front Busbar Earth Position

Back Busbar Earth Position

Back Busbar Earth Position

Feeder Earth Position

Feeder Earth Position

Trip Coil

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

SIC

K3

K1

K2

K3

K3

K95

K95

K95

K95

K95

K95

K91

K91

K91

K91

K91

K2

K2

K2

K2

K91

Status Input

QS

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Figure 1.5 1.5.2 HV Switchgear Both the main and back up trip circuits shall be supervised by trip circuit supervision functions. Either protection relays or discrete trip circuit supervision relays can be used. If protection relays are used then relays energised from the main trip circuit shall be used to supervise the main trip coil and relays energised from the back up trip circuit shall be used to supervise the back up trip coil. The trip circuit supervision shall be so wired as to monitor the whole trip circuit and not only the trip coil. Trip circuit supervision shall monitor the trip circuit while the circuit breaker is in the open and closed position. It shall also be wired so as to monitor the status of the circuit breaker auxiliary contacts. A trip circuit supervision contact for each trip circuit shall be wired into the closing circuit of the circuit breaker to prevent the closing of the circuit breaker in the event of any trip circuit D.C supply fail or a discontinuity in any trip circuit. 1.6 Local / Remote control of Circuit Breakers Manual operation of the circuit breaker shall reside in the back up trip circuit when a breaker is equipped with two trip coils. 1.6.1 MV Switchgear The manual operation of the circuit breaker shall be as per the diagrams. 1.6.1.1 Tripping Circuit

‹ ‹

› ›

› ›

Status Input

K1

K2 QS

QS

I.E

S14

K5 K1 Protection Trip

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On Off

Supervisory On / Off

Trip

Close N

On Off

Supervisory On / Off Trip

Close N

On Off

Figure 1.6 Note: The supervisory on/off switch does not interrupt the local tripping circuit so that in an emergency the breaker can be tripped with the supervisory on/off switch in any position. 1.6.1.2 Closing Circuit Figure 1.7

Protection Trip

TNC

Trip Coil

Sup Aux Trip Relay

Open

Tripping V+

Tripping V-

TNC Close Coil

Sup Aux Trip Relay

Close

Closing V+

Closing V-

Stand off Close Control

Stand off Trip Control

Closing interlocks, e.g. MTR’s

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On

On

Off

Off


Close N

1.6.2 HV Switchgear The manual operation of the circuit breaker shall be as per the diagrams. 1.6.2.1 Tripping Circuit Figure 1.8

L / R

Protection Trip

TNC

Back Up Trip Coil

Local Trip

HV CIRCUIT BREAKER

Sup Aux Trip Relay

Open

Back Up V+ Back Up

V-

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On

On

Off

Off


Close N

1.6.2.2 Closing Circuit Figure 1.9 1.7 Anti-pump timer The close circuit of each circuit breaker shall be fitted with an anti-pump timer. The anti-pump timer will be so connected to prevent multiple closures onto a fault should the close pulse remain active. 1.8 Test Blocks Each switchgear relay chamber or relay panel shall be fitted with PK2 4-way test blocks on all protection CT and protection VT circuits to facilitate connection of test equipment into the circuits. Protection relays shall be connected to the top of the test block arrangement. CT test blocks shall be equipped with shorting strips which short out CT circuits when test block is withdrawn. VT test blocks shall not be equipped with shorting strips. CT’s in MV circuit breaker panels wired to HV relay panels for trfr diff and LV REF protection, shall have their CT test blocks fitted on the HV panels and not on the MV circuit breaker panels. Where this is done, the earthing of the CT neutral shall also be done in the HV panel.

L / R

Protection Close

TNC

Close Coil

Local Close

HV CIRCUIT BREAKER

Sup Aux Trip Relay

Close

Back Up V+

Back Up V-

Closing interlocks, e.g. MTR’s and TCS circuits.

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See below figure for a typical schematic diagram of a CT PK2 4-way test block arrangement. Figure 1.10 1.9 Terminals All terminals for CT circuits shall be Entrelec M6/8 RS. If 4mm2 wiring is used then M10/10 RS terminals shall be used. They shall be equipped with test plugs to allow testing and shorting during on load ratio changes. All terminals for VT circuits shall be Entrelec M6/8 RS All terminals for DC circuits shall be Entrelec M6/8 RS All terminals for AC circuits shall be Entrelec M6/8 RS Terminals for CT and VT earths shall be Entrelec D6/8-ST-RS drop links Terminals for transducer circuits shall be Klippon SAKT2 1.10 Wiring CT wiring shall be coloured wiring i.e. red, yellow, blue CT wiring shall be 2.5mm2

VT wiring shall be black VT wiring shall be 2.5mm2 DC auxiliary wiring shall be grey DC auxiliary wiring shall be 1.5mm2

AC auxiliary wiring shall be black AC auxiliary wiring shall be 1.5mm2

Earth wires shall be green/yellow All wiring shall be lugged with 4mm wide insulated hook blade lugs. 1.11 Current Transformers 1.11.1 General Polarities of CT’s shall be such that P1 of the CT is towards the adjacent circuit breaker. CT’s on the transformer neutral shall be such that P2 of the CT is towards the power transformer.

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8

6

4

2

7

5

3

1

R

W

B

N

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1.11.2 MV Switchgear All current transformers shall have 1A secondaries. 1.11.3 HV Switchgear All current transformers shall have 1A secondaries. 1.11.4 Transformer HV Internal CT’s All 10MVA power transformers shall be equipped with 3 internal CT’s on the HV winding. The following CT’s shall be included: Class TPS – Feeder differential or busbar protection Class TPS – Transformer differential and restricted earth fault Class 10P10 – Overcurrent and high set overcurrent

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1.11.5 HV CT’s HV CT’s for feeders, transformers and bussection/buscouplers shall be as follows: HV Bussection / Buscoupler - 1250A HV Bussection / Buscoupler - 1600A (Type 3a) (Type 3c) (Type 3d) Figure 1.11 Type b CT ‘s were used for a current of 2500 A. This is no longer a standard but may be found on some of the existing systems. The currents of 1600 and 3200 A have been selected to compliment a conductor standard of double or quad UPAS.

1200/1 CL TPS

Core 1

Core 2

Core 3

P1

P2

1200/1000/800/ 600/400/200/1 CL TPS

1200/1000/800/ 600/400/200/1 CL 10P10 15VA

1200/1 CL TPS

Core 1

Core 2

Core 3

P1

P2

1600/1200/1000/ 600/400/200/1 CL TPS

1600/1200/1000/ 600/400/200/1 CL 10P10 15VA

HV Bussection / Buscoupler – 3150 A

P1

P2

3200/2400/2000/1200/800/400/1CL 10P10 15 VA

3200/2400/2000/1200/800/400/1CL 10P10 15 VA

1200/1 CL TPS

Core 1

Core 1

Core 1

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HV Feeders – 1250A HV Feeders – 1600A HV Feeders – 3150 A (Type 1a) (Type 1c) (Type 1d)

1200/1000/800/ 600/400/200/1 CL TPS

1200/1000/800/ 600/400/200/1 CL 10P10 15VA

1200/1000/800/ 600/400/200/1 CL TPS

1200/1 CL TPS

1200/1 CL TPS

Core 1

Core 2

Core 3

Core 4

Core 5

P1

P2

1600/1200/1000/ 600/400/200/1 CL TPS

1600/1200/1000/ 600/400/200/1 CL 10P10 15VA

1600/1200/1000/ 600/400/200/1 CL TPS

1200/1 CL TPS

1200/1 CL TPS

Core 1

Core 2

Core 3

Core 4

Core 5

P1

P2

300/200/150/1 CL TPS

1600/1200/1000 /600/400/200/1 CL TPS

300/200/150/1 CL 10P10 15 VA

1200/1 CL TPS

1200/1 CL TPS

P1

P2

Core 1

Core 1

Core 1

Core 1

Core 1

3200/2400/2000 /1200/800/400/1 CL TPS

1200/1 CL TPS

1200/1 CL TPS

P1

P2

Core 1

Core 2

Core 3

Core 4

Core 5

3200/2400/2000 /1200/800/400/1 CL TPS

3200/2400/2000 /1200/800/400/1 CL 10P10 15 VA

300/200/150/1CL TPS

3200/2400/2000/1200/800/400/1CL TPS

300/200/150/1 CL 10P10 15 VA

1200/1 CL TPS

1200/1 CL TPS

P1

P2

Core 1

Core 1

Core 1

Core 1

Core 1

300/200/150/1 CL TPS

1200/1000/800 /600/400/200/1 CL TPS

300/200/150/1 CL 10P10 15 VA

1200/1 CL TPS

1200/1 CL TPS

P1

P2

Core 1

Core 1

Core 1

Core 1

Core 1

Transformer Bay where bus section = 1600 A (Type 2c)

Transformer Bay where bus section = 3150 A (Type 2d)

Transformer Bay where bus section = 1250 A (Type 2a)

Fig. 1.12

Fig. 1.13

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1.12 Voltage Transformers 1.12.1 MV Switchgear All transformer incomers shall be equipped with voltage transformers. Voltage transformers on transformer incomers shall have 5 limbs. Voltage transformers shall have an open delta winding if directional earth fault has been specified. All metering feeders shall be equipped with voltage transformers. Voltage transformers on metering feeders shall have 3 limbs. Typical values for voltage transformers are Class 0.5 50VA / phase. See figure 1.14 for a typical three limb VT arrangement on a transformer panel. See figure 1.15 for a typical three limb VT arrangement on a metering panel See figure 1.16 for a typical five limb VT arrangement on a transformer panel. Figure 1.14 Figure 1.15

‹ ‹ ‹

∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩

∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩

› › ›

VT Supply Fail

To RTCCP

To Transducer and Voltmeter

Balanced “Dummy” Load

R W B

›Main VT MCB

‹ ‹ ‹

∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩

∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩

› › ›

VT Supply Fail

To metering



R W B

›Main VT MCB

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Figure 1.16 1.13 Protection relays It shall be possible to set or reset relays from a standing position in front of the switchgear relay chamber or relay panel. All protection relays shall be of the numerical type. All protection relays shall be equipped with a RS232 port. For relay standards see PEE Standard 100. 1.14 Trip Isolation Links One of the underlying principles is that trip signals leaving a panel to some external point, must be isolated at the sending end only before leaving the panel. Each trip coil shall have a trip isolation link for testing purposes. In the case of outdoor bays with indoor control panels, both the main and back-up trip circuits shall leave the control panel via trip isolation links to the outdoor circuit breaker. Feeder differential protection shall have trip isolation links in each tripping circuit, regardless of whether the relays are copper or fibre connected. Where transformer protection sits on the primary side panel (e.g. trfr diff and HV and MV REF) the trips form this panel to the MV circuit breaker panel shall go via trip isolation links. Intertrip send circuits shall have trip isolation links. Busstrip/Breaker fail circuits from the bay panels to the buszone panel shall have an isolation link in the bay panel. An isolation link is required for each of the zones, but not for the check zone, e.g. main zone and reserve zone. Bus zone panels shall not have trip links as bus zone isolation shall be done by way of the 4 way control switch. All trip isolation links shall be installed on the front of the relay panel or relay chamber. Breaker fail or breaker fail initiate from a relay panel to the bus zone panel, shall have an isolation link on the relay panel.

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∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩

∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩ ∩

› › ›

VT Supply Fail



R W B

›

Main VT MCB

Test Block

DirectionalRelay

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1.15 Spring Discharged Circuit When a breaker spring is discharged the panel indication shall light up immediately. Simultaneously the timer, that is buswired to all the other panels, shall be energised. On timing out the timer shall close a pair of contacts, which will be used to signal a SCADA alarm. The panel indication and the timer shall not be activated when the breaker is racked out or racked into the feeder or busbar earth position. Figure 1.17 shows a spring discharge circuit on a typical Alstom breaker. S17 (Spring discharged auxiliary contact) is a normally closed contact when the spring discharged, thus when the breaker is removed the light and timer will not be activated. Figure1.17 1.16 Luminous Indicators 1.16.1 MV Switchgear The following indication where applicable shall be present on relay chambers:

Circuit Breaker Open Green Circuit Breaker Closed Red Spring Discharged Amber Gas Alarm Amber Gas Lockout Amber Top/Front Busbar Selected White Bottom/Back Busbar Selected White Top/Front Busbar Earth Selected Amber Bottom/Back Busbar Earth Selected Amber Auto Reclose On White Sensitive Earth Fault On White Cable Earthed Amber Trip Circuit Healthy White

‹

› › ‹ › ‹

K3

K3

S17

› ‹ K3

Buswired to timer circuit

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1.16.2 HV Switchgear The following indication where applicable shall be present on relay panels:

Circuit Breaker Open Green Circuit Breaker Closed Red Spring Discharged Amber Gas Alarm Amber Gas Lockout Amber Isolator Open White Isolator Closed White Earth Switch Open White Earth Switch Closed White Breaker on Local Amber Trip Circuit Healthy White Auto Reclose On White

There shall be a lamp test push button on HV relay panels to test the integrity of the indication lamps. There is no need for a lamp test push button on MV relay chambers as mechanical indication is available. Also the lamps shall be active continuously, i.e. it shall not be activated by a timer circuit. 1.16.3 Top / Bottom Busbar type switchgear A typical example of an indication circuit on an Alstom type breaker is shown in Figure 1.13. By connecting the “Bottom Busbar” to the integral earth micro switch (I.E) it prevents the “Bottom Busbar” indicating when the breaker is racked into the feeder earth position.

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Figure 1.18 1.17 Voltmeters and Voltage Transducers The scale of voltmeters shall be 80-120%. The voltmeter shall be selectable to R-Y, R-B and Y-B. The voltage transducer shall be connected across the blue and white phases. The voltage transducer shall be an 80-130V, 0-20mA active transducer. 1.18 Ammeters and Current Transducers The scale of ammeters shall be 0-120%. There shall be one ammeter and a ammeter selector switch. The ammeter shall be selectable to all three phases and to an OFF position. The current transducer shall be connected in the white phase. The current transducer shall be a 0-20mA passive transducer. 1.19 Labels All protection relays, auxiliary relays, indications lamps, pushbuttons etc. shall be adequately labelled. Only white on black trafalite labels shall be used, which must be secured with screws. Labelling of relay panels and relay chambers shall be as per example: “ Trfr 3 132kV Relay Panel”, “Trfr 3 11kV Relay Chamber”.

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› ‹ ‹ ›

› ‹ ‹

› ›

QS

QS

S17

I.E

› ‹ K3

QS

Breaker Closed

Breaker Open

Cable Earthed

Bottom Busbar Selected

Top Busbar Selected

Spring Discharged

S2

S2

‹ ›Service Position

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1.20 Drawings The panel drawings shall include

A protection block diagram AC Key diagrams DC Key diagrams A protection relay configuration schedule 1.21 General Substation Layout Numbering As a general rule transformers and bussections will be numbered in ascending order from the left to the right while having ones back towards the substation source. The two sets of isolators of each bussection bay will be termed a and b respectively from the left to the right while having one’s back towards the substation source. Similarly, for an outdoor double busbar substation, numbers shall apply top to bottom, i.e. the busbar furthest away shall be busbar 1, alternatively the main busbar. The phase furthest away (in a flat busbar formation) would be the red phase. 1.22 SCADA 1.22.1 Single Busbar type switchgear A typical example of SCADA circuit breaker statuses on an Alstom type breaker is shown in Figure 1.19. By connecting the “Service Position” to the integral earth micro switch (I.E) it prevents the “Service Position” indicating when the breaker is racked into the feeder earth position. Figure 1.19

› ‹ ‹ ›

› ‹ ‹ ›

› ‹ ‹

› ›

›

X103

X101

X102

X106

X111

QS

QS

S17

I.E

Common

Closed

Open

Feeder Earth Selected

Service Position

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1.22.2 Top / Bottom Busbar type switchgear The following SCADA statuses shall be wired to the isolated position plug: Breaker Open Breaker Closed Feeder Earth Selected Top Busbar Selected Bottom Busbar Selected The following SCADA controls shall be wired to the isolated position plug: Circuit Breaker Trip Circuit Breaker Close ARC Facility Switched On ARC Facility Switched Off Sensitive EF Switched On Sensitive EF Switched Off On completion of on-site commissioning the SCADA common to the following statuses shall be removed from the isolated/test position plug. This link is shown by the asterix below in Figure 1.19. Feeder Earth Selected Top Busbar Selected Bottom Busbar Selected This will prevent control receiving these statuses while the breaker is racked into the isolated/test position. See PEE 101 for complete SCADA interface requirements A typical example of SCADA circuit breaker statuses on an Alstom type breaker is shown in Figure 1.20. By connecting the “Bottom Busbar” to the integral earth micro switch (I.E) it prevents the “Bottom” indicating when the breaker is racked into the feeder earth position. By connecting the “Top Busbar” to the integral earth micro switch (I.E) it makes it possible to remove the indication when the breaker is racked into the isolated/test position.

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Figure 1.20 1.23 Transformer Alarms and Indications Figure 1.21 depicts a typical power transformer trip annunciator. Figure 1.22 depicts a typical power transformer alarm annunciator. Figure 1.21

› ‹ ‹ ›

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› ‹ ‹

› ›

›

X103

X101

X102

X106

QS

QS

S17

I.E

Common

Closed

Open

Feeder Earth Selected

Top Busbar Selected

Bottom Busbar Selected

X104

X105

*

S2

S2

Winding Temperature

Main Tank Buchholz

Tap Change Buchholz

Oil Temperature

Main Tank Pressure Relief

Tap Change Pressure Control

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Figure 1.22 See PEE 102 for complete power transformer alarm and indication requirements. 1.24 Isolator Auxilliary Contacts Busbar isolators shall be equipped with: 8 “M” auxiliary contacts 8 “N” auxiliary contacts 8 “G” auxiliary contacts 2 “F” auxiliary contacts Line isolators shall be equipped with: 8 “M” auxiliary contacts 8 “N” auxiliary contacts 1.25 Breaker Fail Protection On older systems, breaker fail protection was restricted to double busbar systems with full bus zone protection. On H-type HV configurations (2x incomers to a single busbar system feeding 2x or 3x power transformers, with bus sections between transformer T-offs) Breaker Fail protection must be applied as per fig. 1.23 below.

Winding Temperature

Main Tank Buchholz

Oil Temperature

T/C Tank Low oil level

Main Tank Low oil level

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For more detail on the MV side, see the sketches on MV arc protection in this document.

Breaker fail Trips Remote feeder breaker

CB01 via MTR01

CB01 Remote fdr breaker via M-P (fibre fdr diff) CB02 via MTR-T CB04 via MTR-T CB04 CB01 via MTR-T CB02 via MTR-T Other MV incomers via MV arc protection system. (See

PDG V.10) CB02 CB01 via MTR01 CB03 via its MTR (Assume CB03 sits on other incomer.)

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CB01BU-P

M-P

MTR

BU-P

M-P

MTR

BU-P

BU-P

M-P

BF-I

BF-I

BF1

BF-In

BF1- In

BF1 send to the remote

BFR received from remote end.

BF-R

BF1

CB 04

CB 02

BFR

BF4

BF2 BF-InBF2 to CB3

BF3

Assume other incomer = CB03

BF enabled

BF enabled

BF enabled BF4

To MV arc protection scheme. (See (PDG Rev 10)

01

-T

Fig. 1.23

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LEFT BLANK

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Transformer Protection – Type 1 See Fig. 2.2

Transformer Protection – Type 2a See Fig. 3.1

Transformer Feeder Protection – Type 1 See Fig. 4.1

Transformer Protection – Type 2b See Fig. 3.2

A. Typical Plant Layouts

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Transformer Feeder Protection – Type 2 See Fig. 5.1

Feeder Protection – Type 1a/b/c/d/e See Fig. 6.1/7.1/8.1/9.1&9.2/10.1

Feeder Protection – Type 2 See Fig. 11.1

Feeder Protection – Type 3 See Fig. 12.1

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Buscoupler / Bussection Protection – Type 1,2,3 See Fig. 13.1/14.1/15.1

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2. Transformer Protection – Type 1 (Fig. 2.2) 2.1 Basic The scheme relates to a power transformer having a local HV and a local MV breaker. The basic protection scheme shall consist of transformer differential protection, HV restricted earth fault, MV restricted earth fault, HV IDMT and high set overcurrent, MV IDMT overcurrent, MV IDMT earth fault and Standby earth fault. If the transformer has an earthed primary winding HV IDMT and high set earth fault shall be included. The HV IDMT and high set overcurrent shall be a separate relay from that of the

differential and restricted earth fault relays. The transformer differential, HV restricted earth fault, LV restricted earth fault, HV

IDMT and high set overcurrent protection shall reside on the HV relay panel. The MV IDMT phase overcurrent, MV IDMT earth fault and standby earth fault

protection shall reside on the MV relay chamber. The transformer trips shall be marshalled to the HV panel. There shall be one standby earth fault relay per switchboard, which will reside on the

Transformer No.1 MV relay chamber. The standby earth fault shall be a discrete relay. Standby earth fault tripping shall be buswired via trip isolate links to the other

transformer MV breakers. There shall be no standby earth fault protection when the transformer secondary

winding is solidly earthed. 2.2 Minimum tripping requirements 2.2.1 Transformer differential It is required to operate both the HV and MV main trip coils directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 2.2.2 HV Restricted earth fault It is required to operate both the HV and MV main trip coils directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 2.2.3 MV Restricted earth fault It is required to operate both the HV and MV main trip coils directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact.

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2.2.4 HV IDMT overcurrent It is required to operate the HV and MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 2.2.5 HV High set overcurrent It is required to operate the HV and MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 2.2.6 HV IDMT earth fault It is required to operate the HV and MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 2.2.7 HV High set earth fault It is required to operate the HV and MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 2.2.8 MV IDMT overcurrent It is required to operate the MV back up trip coil directly. 2.2.9 MV IDMT earth fault It is required to operate the MV back up trip coil directly. 2.2.10 Standby earth fault It is required to operate the MV back up trip coil directly. Note: If protection relays have extra output contacts, extra tripping to alternate trip coils shall be used. 2.3 Master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel. The master trip relay shall be operated by the following functions: HV restricted earth fault MV restricted earth fault

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Transformer differential HV IDMT overcurrent HV High set overcurrent HV IDMT earth fault HV High set earth fault Transformer Buchholz trip – Main tank Transformer pressure relief trip – Main tank Transformer oil temperature trip OLTC Buchholz trip / OLTC pressure control trip MV ARC detection HV Buszone The master trip relay shall operate both HV and MV main and back up trip coils and a contact shall be made available to trip the transformer cooler fans in the event of a fault. The HV circuit breaker and MV circuit breaker close circuits shall be interlocked with the Master trip relay normally closed contact. The master trip relay shall reside on the HV relay panel and be energised from the main trip coil DC supply. See Figure 2.1 Figure 2.1 2.4 Main protection The following protection shall be deemed to be the main protection: Transformer differential HV Restricted earth fault

JJ

Main V+

Direct ProtectionTrips

ProtectionTrips

Main Trip Coil

Master Trip Relay

Master Trip

Main V-

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MV Restricted earth fault The power supplies of the main protection shall be energised from the main trip coil supply. 2.5 Back up protection The following protection shall be deemed to be the back up protection: HV IDMT overcurrent HV high set overcurrent HV IDMT earth fault HV high set earth fault MV IDMT overcurrent MV IDMT earth fault Standby earth fault The power supplies of the back up protection shall be energised from the back up trip coil supply. In the case where the MV circuit breaker has only one trip coil, the protection shall be energised from the tripping circuit. 2.6 Transformer trips Transformer trips include the following: Transformer Buchholz trip Transformer pressure relief trip Transformer oil temperature trip Transformer winding temperature trip OLTC Buchholz trip / OLTC pressure control trip 2.6.1 Minimum tripping requirements Transformer Buchholz trip, Transformer pressure relief trip, Transformer oil temperature trip, OLTC Buchholz trip / OLTC pressure trip shall operate the master trip relay. The transformer winding temperature shall not operate the master trip relay but shall trip the MV back up trip coil so as to disconnect the load. 2.6.2 Marshalled to main protection relay This option is where all the transformer trips are marshalled to the status inputs on the main protection relay (e.g. transformer differential) on the HV panel. The trip outputs on the relay shall be configured according to the type of transformer trip and the respective tripping requirement. As direct trips to the circuit breakers are available on the main protection relay, these shall be configured as extra tripping when tripping the master trip relay is a minimum requirement. The relay shall be configured to indicate which

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transformer trip was received. If the relay does not have configurable indication available a separate indication mimic shall be used. The main trip supply shall be used. 2.6.3 Marshalled directly to the master trip relay or MV trip coil This option is where the transformer trips are marshalled directly to the master trip relay or the MV trip coil depending on the type of transformer trip. An indication mimic shall be connected in parallel to indicate which transformer trip operated. The main trip supply shall be used. 2.6.4 Marshalled to auxiliary flagging relays This option is where the transformer trips are marshalled to auxiliary flagging relays. Each transformer trip shall operate a unique auxiliary flagging relay. The auxiliary relay shall operate the master trip relay or MV trip coil depending on the type of transformer trip. The main trip supply shall be used. 2.7 MV ARC detection An ARC detection master relay shall be installed on each transformer MV panel. The ARC detection protection shall operate the MV back up trip coil directly as well as operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 2.8 HV Buszone The buszone protection shall trip the HV back up trip coil directly as well as operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 2.9 Breaker Fail Breaker fail functionality shall be included on all future 132 kV substations. Although fig. 2.2 displays the simplest form of breaker fail protection (in substations with a full bus zone protection scheme) breaker fail protection shall also be used on other 132 kV protection schemes. Fig 1.23 displays the scheme to be used on substations without a full bus zone scheme. The breaker fail functionality shall be initiated from all the protection functions and be supervised by a current pickup. The breaker fail functionality shall reside in the back-up protection relay, with a breaker fail initiate contact from the main protection output to the back-up protection input. A single contact could be used for both ARC and Breaker Fail Initiate. A breaker fail signal shall be send to the bus zone panel (not a breaker fail initiate) via an isolation link to be fitted on the relay panel.

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2.10 Transformer Alarms The following alarms shall be marshalled to the relay panel: Low oil level – Main tank Low oil level – Tap Change tank Buchholz – Main tank Buchholz – OLTC (alternatively from the pressure control device in the OLTC) Winding Temperature Oil Temperature Cooler Supply Fail See Section 1.23 for mimic layout Also see PEE 102 for power transformer alarms and indication requirements. 2.11 Block Diagram See Figure 2.2 for a typical transformer – type 1 protection block diagram.

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Figure 2.2

Buch - Main

Buch - OLTC

Winding Temp

Oil Temp

Press Relief

IDMT O/C &E/F

HV REF MV REF TX Differential

IDMT O/C High Set O/C

Standby E/F

Main Trip Coil

B/U Trip Coil

Master Trip Relay

Buszone

ARC Detection

Main Trip Coil B/U Trip Coil

Close Coil

HV Relay Panel

MV Relay Chamber

MTR TCS-M TCS-B

Close Coil MTR TCS-M TCS-B

300/200/150/1 Class 10P10 15VA

300/200/150/1 Class TPS

1200/1 Class TPS 1200/1 Class TPS

500/1 Class 10P10 15VA

See Section 1.11.5 for complete CT details

HV Buszone Panel

Main Zone

Check Zone

Breaker Fail

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3. Transformer Protection – Type 2a/b (Fig. 3.1) 3.1 Basic The scheme relates to a power transformer having two local HV beakers and a local MV breaker. Fig 3.1 does not reflect breaker fail protection. Breaker fail protection needs to be added to this scheme in accordance with fig. 1.23. 3.2 Minimum tripping requirements 3.2.1 Transformer differential It is required to operate both the HV main trip coils and the MV main trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 3.2.2 HV Restricted earth fault It is required to operate both the HV main trip coils and the MV main trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 3.2.3 MV Restricted earth fault It is required to operate both the HV main trip coils and the MV main trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 3.2.4 HV IDMT overcurrent It is required to operate both the HV back up trip coils and the MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 3.2.5 HV High set overcurrent It is required to operate both the HV back up trip coils and the MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 3.2.6 HV IDMT earth fault It is required to operate both the HV back up trip coils and the MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact.

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3.2.7 HV High set earth fault It is required to operate both the HV back up trip coils and the MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 3.2.8 MV IDMT overcurrent It is required to operate the MV back up trip coil directly. 3.2.9 MV IDMT earth fault It is required to operate the MV back up trip coil directly. 3.2.10 Standby earth Fault It is required to operate the MV back up trip coil directly. Note: If protection relays have extra output contacts, extra tripping to alternate trip coils shall be used. 3.3 Master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel. The master trip relay shall be operated by the following functions: HV restricted earth fault MV restricted earth fault Transformer differential HV IDMT overcurrent HV High set overcurrent HV IDMT earth fault HV High set earth fault Transformer Buchholz trip – Main tank Transformer pressure relief trip – Main tank Transformer oil temperature trip OLTC Buchholz trip / OLTC pressure control trip MV ARC detection HV Busbar protection The master trip relay shall operate the two HV main and back up trip coils and the MV main and back up trip coils and a contact shall be made available to trip the transformer cooler fans in the event of a fault. Both the HV circuit breakers and the MV circuit breaker close circuits shall be interlocked with the Master trip relay normally closed contact.

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The master trip relay shall reside on the HV relay panel and be energised from the main trip coil DC supply. See Figure 2.1. 3.4 Main protection See 2.4 3.5 Back up protection See 2.5 3.6 Transformer trips See 2.6 3.6.1 Minimum tripping requirements See 2.6.1 3.6.2 Marshalled to main protection relay See 2.6.2 3.6.3 Marshalled directly to the master trip relay or MV trip coil See 2.6.3 3.6.4 Marshalled to auxiliary flagging relays See 2.6.4 3.7 MV ARC detection See 2.7 3.8 HV Busbar Protection It is required to operate both the HV back up trip coils and the MV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 3.9 Transformer Alarms See 2.9

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3.10 Block Diagram See Figure 3.1 for a typical transformer – type 2a protection block diagram and fig. 3.2 for a typical transformer – type 2b protection block diagram.

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Figure 3.1

Buch - Main

Buch - OLTC

Winding Temp

Oil Temp

Pressure Relief

IDMT O/C &E/F



Standby E/F


Busbar Prot

ARC Detection


Master Trip Relay


HV Relay Panel

MV Relay Chamber

MTR TCS-M TCS-B

Close Coil

MTR TCS-M TCS-B


Close Coil

See Buscoupler/Bussection Protection – Type 2 for details of bussection protection (Section 14)


300/200/150/1 Class TPS

300/200/150/1 Class 10P10 15VA

1200/1000/800/ 600/400/200/1 Class TPS

500/1 Class 10P10 15VA

1200/1000/800/ 600/400/200/1 Class TPS

1200/1000/800/ 600/400/200/1 Class TPS

Rev 10 – 15 Sep 2010

44

Figure 3.2

Buch - Main

Buch - OLTC

Winding Temp

Oil Temp

Pressure Relief

IDMT O/C &E/F



Standby E/F


Busbar Prot

ARC Detection


Master Trip Relay


HV Relay Panel

MV Relay Chamber

MTR TCS-M TCS-B



Close Coil

See Feeder Protection – Type 3 for details of feeder protection (Section 12)



500/1 Class 10P10 15VA

300/200/150/1 Class TPS

300/200/150/1 Class 10P10 15VA

1200/1000/800/ 600/400/200/1 Class TPS

1200/1000/800/ 600/400/200/1 Class TPS

1200/1000/800/ 600/400/200/1 Class TPS

Rev 10 – 15 Sep 2010

45

4. Transformer Feeder Protection – Type 1 (Fig. 4.1) 4.1 Basic The scheme relates to a power transformer having a remote HV breaker and a local MV breaker. The basic scheme shall consist of transformer differential, HV restricted earth fault, MV restricted earth fault, HV IDMT and high set overcurrent, HV IDMT earth fault, MV IDMT phase overcurrent, MV IDMT earth fault, MV directional overcurrent, standby earth fault and feeder differential. If the transformer has an earthed primary winding HV IDMT and high set earth fault shall be included. There shall be a local and a remote HV relay panel. The MV IDMT phase overcurrent, MV IDMT earth fault, MV directional overcurrent

and standby earth fault protection shall reside on the MV relay chamber. The transformer differential, HV Restricted earth fault, MV Restricted earth fault and

feeder differential protection shall reside on the local HV panel. There shall also be a discrete intertrip send and receive relay on the local HV panel.

The HV IDMT overcurrent, HV High Set overcurrent, HV IDMT earth fault and feeder differential protection shall reside on the remote HV panel. There shall also be a discrete intertrip send and receive relay on the remote HV panel.

There shall be one standby earth fault relay per switchboard, which will reside on the Transformer No. 1 MV relay chamber.

The standby earth fault shall be a discrete relay. Standby Earth Fault tripping shall be buswired via trip isolate links to the other

Transformer MV breakers. There shall be no standby earth fault protection when the transformer secondary

winding is solidly earthed. Local shall mean the substation where the transformer is situated. 4.2 Minimum tripping requirements 4.2.1 Transformer differential It is required to operate the MV main trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 4.2.2 HV Restricted earth fault It is required to operate the MV main trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact.

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4.2.3 MV Restricted earth fault It is required to operate the MV main trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 4.2.4 HV IDMT overcurrent It is required to operate the HV back up trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 4.2.5 HV High Set overcurrent It is required to operate the HV back up trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 4.2.6 HV IDMT earth fault It is required to operate the HV back up trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 4.2.7 HV High Set earth fault It is required to operate the HV back up trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 4.2.8 MV IDMT overcurrent It is required to operate the MV back up trip coil directly. 4.2.9 MV IDMT earth fault It is required to operate the MV back up trip coil directly. 4.2.10 MV directional overcurrent It is required to operate the MV back up trip coil directly and to operate the master trip relay situated on the local HV panel. Each trip destination shall be sourced from a separate suitably rated output contact.

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4.2.11 Standby earth fault It is required to operate the MV back up trip coil directly. 4.2.12 Feeder differential It is required to operate the HV and MV main trip coils directly. Note: If protection relays have extra output contacts, extra tripping to alternate trip coils shall be used. 4.3 Local HV master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel. The master trip relay shall be operated by the following functions: HV restricted earth fault MV restricted earth fault Transformer differential MV directional overcurrent Transformer Buchholz trip – Main Tank Transformer pressure relief trip – Main Tank Transformer oil temperature trip OLTC Buchholz trip / OLTC pressure control trip MV ARC detection The master trip relay shall operate the MV main and back up trip coils, the resident intertrip send relay and a contact shall be made available to trip the transformer cooler fans in event of a fault. The MV circuit breaker close circuit shall be interlocked with the resident master trip relay normally closed contact. The master trip relay shall be energised from the main trip coil DC supply. See Figure 2.1. 4.4 Remote HV master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel. The master trip relay shall be operated by the following functions: HV IDMT overcurrent HV high set overcurrent HV IDMT earth fault HV high set earth fault HV Buszone

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The master trip relay shall operate the HV main and back up trip coils and the resident intertrip send relay. The HV circuit breaker close circuit shall be interlocked with the resident master trip relay normally closed contact. The master trip relay shall be energised from the main trip coil DC supply. See Figure 2.1. 4.5 Intertrip send / receive relay The Intertrip send relay shall apply both the positive and negative D.C. to the pilot pair. The Intertrip send relay shall be energised from the main trip coil DC supply. The Intertrip receive relay shall operate the main and back up trip coil. The resident circuit breaker close circuit shall be interlocked with the Intertrip receive normally closed contact. 4.6 Main protection The following protection shall be deemed to be the main protection: Transformer differential HV Restricted earth fault MV Restricted earth fault Feeder differential The power supplies of the main protection shall be energised from the main trip coil supply. 4.7 Back up protection The following protection shall be deemed to be the back up protection: HV IDMT overcurrent HV high set overcurrent HV IDMT earth fault HV high set earth fault MV IDMT overcurrent MV IDMT earth fault MV directional overcurrent Standby earth fault The power supplies of the back up protection shall be energised from the back up trip coil supply. In the case where the MV circuit breaker has only one trip coil, the protection shall be energised from the tripping circuit.

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4.8 Transformer trips See paragraph 2.6 4.9 MV ARC detection An ARC detection master relay shall be installed on each transformer MV panel. The ARC detection protection shall operate the MV back up trip coil directly as well as operate the master trip relay on the local HV panel. 4.10 HV Buszone The buszone protection shall trip the HV back up trip coil directly as well as operate the master trip relay on the remote HV panel. Each trip destination shall be sourced from a separate suitably rated output contact. 4.11 Breaker Fail Breaker fail protection shall be superimposed on the PBD of fig. 4.1. If the remote HV breaker fails, the MV breaker shall trip via an intertrip received by the local HV Relay Panel. Failing of the MV breaker shall send a trip to the remote HV breaker via the local HV Relay Panel. The MV breaker shall also send trips to other MV breakers in line with Fig. 1.23. The breaker fail functionality shall be initiated from all the protection functions and be supervised by a current pickup. The breaker fail functionality shall reside in the back-up protection relay, with a breaker fail initiate contact from the main protection output to the back-up protection input. A single contact could be used for both ARC and Breaker Fail Initiate. A breaker fail signal shall be send to the bus zone panel (not a breaker fail initiate) via an isolation link to be fitted on the relay panel. 4.12 Block Diagram See Figure 4.1 for a typical transformer feeder - type 1 protection block diagram.

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Figure 4.1

Buch. Main

Buch. T.C

Winding Temp

Oil Temp

Press Relief

IDMT O/C &E/F

Directional O/C

Trfr Differential HV R.E.F MV R.E.F

Fdr Differential

IDMT O/C &E/F High Set O/C

Fdr Differential

Standby E/F

Master Trip

Intertrip Send

Intertrip Receive

Main Trip Coil

B/U Trip Coil

Pilots

Master Trip

Intertrip Send

Intertrip Receive

Pilots

ARC detection

Main Trip Coil

B/U Trip Coil

Close Coil MTR TCS-M TCS-B ITR

Remote HV Relay Panel

MTR TCS-M TCS-B

Close Coil ITR

Local HV Relay Panel

MV Relay Chamber

1200/1 Class TPS

1200/1 Class TPS

300/200/150/1 Class TPS

1200/1000/800/ 600/400/200/1 Class TPS

1200/1000/800/ 600/400/200/1 Class TPS

1200/1000/800/ 600/400/200/1 Class 10P10 15VA

500/1 Class 10P10 15VA


Buszone

HV Buszone Panel

Main Zone

Check Zone

Breaker Fail

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5. Transformer Feeder Protection – Type 2 (Fig. 5.1) 5.1 Basic The scheme relates to a power transformer having a remote HV breaker, a local HV bus section breaker and a local MV breaker. The basic scheme shall consist of transformer differential, HV restricted earth fault, MV restricted earth fault, HV IDMT overcurrent, HV high set overcurrent, HV IDMT earth fault, MV IDMT phase overcurrent, MV IDMT earth fault, MV directional overcurrent, standby earth fault and feeder differential. There shall be a local and a remote HV relay panel. Trips will be marshalled to the

bus section relay panel as well. The MV IDMT phase overcurrent, MV IDMT earth fault, MV directional overcurrent

and standby earth fault protection shall reside on the MV relay chamber. The transformer differential, HV Restricted earth fault, MV Restricted earth fault, HV

high set overcurrent and feeder differential protection shall reside on the local HV panel. There shall also be a discrete intertrip send relay on the local HV panel.

The HV IDMT overcurrent, HV IDMT earth fault and feeder differential protection shall reside on the remote HV panel. There shall also be a discrete intertrip receive relay on the remote HV panel.

There shall be one standby earth fault relay per switchboard, which will reside on the Transformer No. 1 MV relay chamber.

The standby earth fault shall be a discrete relay. Standby Earth Fault tripping shall be buswired via trip isolate links to the other

Transformer MV breakers. There shall be no standby earth fault protection when the transformer secondary

winding is solidly earthed. The bus section and transformer CT’s that are used for feeder differential shall either

be summated in an external summation CT or fed into a two CT input feeder differential relay.

Local shall mean the substation where the transformer is situated. 5.2 Minimum tripping requirements 5.2.1 Transformer differential It is required to operate the MV main trip coil and HV bus section main trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact.

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5.2.2 HV Restricted earth fault It is required to operate the MV main trip coil and HV bus section main trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 5.2.3 MV Restricted earth fault It is required to operate the MV main trip coil and HV bus section main trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 5.2.4 HV IDMT overcurrent It is required to operate the HV back up trip coil directly. 5.2.5 HV High set overcurrent It is required to operate the MV back up trip coil and HV bus section back up trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 5.2.6 HV IDMTL earth fault It is required to operate the HV back up trip coil directly. 5.2.7 MV IDMT overcurrent It is required to operate the MV back up trip coil directly. 5.2.8 MV IDMT earth fault It is required to operate the MV back up trip coil directly. 5.2.9 MV Directional Overcurrent It is required to operate the MV back up trip coil directly and to operate the resident master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. 5.2.10 Standby Earth Fault It is required to operate the MV back up trip coil directly.

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5.2.11 Feeder differential It is required to operate the HV, MV and HV bus section main trip coils directly. Note: If protection relays have extra output contacts, extra tripping to alternate trip coils shall be used. 5.3 Local HV Master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel. The master trip relay shall be operated by the following functions: HV restricted earth fault MV restricted earth fault Transformer differential HV high set overcurrent MV directional overcurrent Transformer Buchholz trip – Main Tank Transformer pressure relief trip – Main Tank Transformer oil temperature trip OLTC Buchholz trip / OLTC pressure control trip MV ARC detection The master trip relay shall operate the MV main and back up trip coils, the HV bus section main and back up trip coils, the resident intertrip send relay and a contact shall be made available to trip the transformer cooler fans in event of a fault. The MV and HV bus section circuit breaker close circuits shall be interlocked with the resident master trip relay normally closed contact. The master trip relay shall be energised from the main trip coil DC supply. See Figure 2.1. 5.4 Remote HV Master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel. The master trip relay shall be operated by the following functions: HV Buszone The master trip relay shall operate the HV main and back up trip coils. The HV circuit breaker close circuit shall be interlocked with the resident master trip relay normally closed contact. The master trip relay shall be energised from the main trip coil DC supply. See Figure 2.1.

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5.5 Intertrip Send / Receive relay The Intertrip send relay shall apply both the positive and negative D.C. to the pilot pair. The Intertrip send relay shall be energised from the main trip coil DC supply. The Intertrip receive relay shall operate the main and back up trip coil. The resident circuit breakers close circuits shall be interlocked with the Intertrip receive normally closed contacts. 5.6 Main Protection See 4.6. 5.7 Back Up Protection See 4.7 5.8 Transformer trips See 2.6 5.9 ARC Detection See 4.9 5.10 Block Diagram See Figure 5.1 for a typical transformer feeder - type 2 protection block diagram.

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Figure 5.1

Buch. Main

Buch. T.C

Winding Temp

Oil Temp

Press Relief

Trfr Differential HV R.E.F MV R.E.F

Fdr Differential

IDMT O/C &E/F

Fdr Differential

Intertrip Receive

Main Trip Coil

B/U Trip Coil

Pilots

Master Trip Relay

Intertrip Send

Pilots

Main Trip Coil

B/U Trip Coil

High Set O/C

IDMT O/C &E/F

Directional O/C

Standby E/F

ARC detection

Main Trip Coil

B/U Trip Coil

MTR TCS-M TCS-B

Close Coil

MV Relay Chamber

Local HV Relay Panel

Remote HV Relay Panel

Close Coil MTR TCS-M TCS-B ITR

Buszone

Master Trip

MTR

TCS-M TCS-B Close Coil See Buscoupler/Bussection

Protection – Type 2 for details of bussection protection (Section 14)

1200/1000/800/ 600/400/200/1 Class TPS


1200/1000/800/ 600/400/200/1 Class TPS

1200/1 Class TPS

1200/1 Class TPS

Main

Check

1200/1000/800/ 600/400/200/1 Class TPS

300/200/150/1 Class TPS

300/200/150/1 Class 10P10 15VA

1200/1000/800/ 600/400/200/1 Class TPS

500/1 Class 10P10 15VA

Rev 10 – 15 Sep 2010

56

6. Feeder Protection – Type 1A (Fig. 6.1) 6.1 Basic The scheme relates to a typical 22kV and below interconnector protection scheme. The basic scheme shall consist of feeder differential, IDMT overcurrent and IDMT earth fault. The IDMT overcurrent and earth fault shall be a separate relay from that of the

feeder differential relay. 6.2 Minimum tripping requirements 6.2.1 Feeder differential It is required to operate the main trip coil directly. 6.2.2 IDMT overcurrent It is required to operate the back up trip coil directly. 6.2.3 IDMT earth fault It is required to operate the back up trip coil directly. Note: If protection relays have extra output contacts, extra tripping to alternate trip coils shall be used. 6.3 Master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel or be hand reset. The master trip relay shall be operated by the following functions: Arc detection The master trip relay shall operate both main and back up trip coils. The circuit breaker close circuit shall be interlocked with the Master trip relay normally closed contact. The master trip relay shall be energised from the main trip coil DC supply. See Figure 2.1. 6.4 Main Protection The following protection shall be deemed to be the main protection: Feeder Differential

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The power supplies of the main protection shall be energised from the main trip coil supply. 6.5 Back up protection The following protection shall be deemed to be the back up protection: IDMT Overcurrent IDMT Earth fault The power supplies of the back up protection shall be energised from the back up trip coil supply. In the case where the MV circuit breaker has only one trip coil, the protection shall be energised from the tripping circuit. 6.6 ARC Detection An ARC detection master relay shall be installed on each interconnector panel. The ARC detection protection shall operate the MV back up trip coil directly as well as operate the master trip relay. The power supply of the Arc detection protection shall be energised from the main trip coil supply. 6.7 Block Diagram See Figure 6.1 for a typical interconnector - type 1A protection block diagram. Figure 6.1 – Type 1A

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

MV Relay Chamber

Close Coil

ARC Detection

Feeder Differential

Master Trip

MTR TCS-M TCS-B

400/300/1 Class TPS

400/200/1 Class 10P10 15VA

Rev 10 – 15 Sep 2010

58

7. Feeder Protection – Type 1B (Fig. 7.1) 7.1 Basic The scheme relates to a typical 11kV and below distribution feeder protection scheme. The basic scheme shall consist of IDMT overcurrent and IDMT earth fault. A suitably rated Class TPS CT shall be included in the switchgear for possible future use. 7.2 Minimum tripping requirements 7.2.1 IDMT overcurrent It is required to operate the main and back up trip coils directly. 7.2.2 IDMT earth fault It is required to operate the main and back up trip coils directly. 7.3 Main Protection The following protection shall be deemed to be the main protection: IDMT Overcurrent IDMT Earth fault The power supplies of the main protection shall be energised from the main trip coil supply. 7.4 Block Diagram See Figure 7.1 for a typical distribution feeder - type 1B protection block diagram. Figure 7.1 – Feeder Protection Type 1B

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

MV Relay Chamber

Close Coil TCS-M TCS-B

Future Feeder Differential

400/300/1 Class TPS

400/200/1 Class 10P10 15VA

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59

Feeder Protection – Type 1C (Fig. 8.1) 8.1 Basic The scheme relates to a typical 22kV and below rural overhead feeder protection scheme. The basic scheme shall consist of IDMT overcurrent, IDMT earth fault and sensitive earth fault. All these functions may reside in one relay. A suitably rated Class TPS CT should be included in the switchgear for possible future use. 8.2 Minimum tripping requirements 8.2.1 IDMT overcurrent It is required to operate the main and back up trip coils directly. 8.2.2 IDMT earth fault It is required to operate the main and back up trip coils directly. 8.2.3 Sensitive earth fault It is required to operate the main and back up trip coils directly. 8.3 Main Protection The following protection shall be deemed to be the main protection: IDMT Overcurrent IDMT Earth fault Sensitive Earth fault The power supplies of the main protection shall be energised from the main trip coil supply. 8.4 Auto reclose The panel shall have auto reclose functionality. The auto reclose functionality can reside in one of the protection relays. The following protection functions shall initiate auto reclose:

IDMT Overcurrent IDMT Earthfault

8.5 Block Diagram See Figure 8.1 for a typical feeder - type 1C protection block diagram.

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Figure 8.1 – Feeder Protection Type 1C 9. Feeder Protection – Type 1D (Fig. 9.1 & 9.2) 9.1 Basic The scheme relates to a typical 22kV and below metering feeder protection scheme. The basic scheme shall consist of IDMT overcurrent and IDMT earth fault. A suitably rated Class TPS CT should be included in the switchgear for possible future use. 9.2 Minimum tripping requirements 9.2.1 IDMT overcurrent It is required to operate the main and back up trip coils directly. 9.2.2 IDMT earth fault It is required to operate the main and back up trip coils directly. 9.3 Main Protection The following protection shall be deemed to be the main protection: IDMT Overcurrent IDMT Earth fault The power supplies of the main protection shall be energised from the main trip coil supply.

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

MV Relay Chamber



Auto Reclose

Sensitive E/F

400/300/1 Class TPS

400/200/1 Class 10P10 15VA

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61

9.4 Block Diagram Figure 9.1 – 11 kV Metering Feeder Type 1D Figure 9.2 – 22 kV Metering Feeder Type 1D

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

MV Relay Chamber


Metering


400/300/1 Class TPS

400/200/1 Class 10P10 15VA

400/200 /100/5 Class 0.5

11kV /110V 50VA/p 3 limb VF 1.2

400/200 /100/5 Class 0.5

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

MV Relay Chamber


Metering


400/300/1 Class TPS

400/200/1 Class 10P10 15VA

400/200 /100/1 Class 0.5

22kV /110V 50VA/p 3 limb VF 1.2

400/200 /100/1 Class 0.5

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10. Feeder Protection – Type 1E 10.1 Basic The scheme relates to a typical HV feeder protection scheme. The basic scheme shall consist of feeder differential protection, IDMT overcurrent and IDMT earth fault. The IDMT overcurrent and earth fault shall be a separate relay from that of the

feeder differential relay. 10.2 Minimum tripping requirements 10.2.1 Feeder Differential Protection It is required to operate the main trip coil directly. 10.2.2 IDMT overcurrent It is required to operate the back up trip coil directly. 10.2.3 IDMT earth fault It is required to operate the back up trip coil directly. Note: If protection relays have extra output contacts, extra tripping to alternate trip coils shall be used. 10.3 Master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel or be hand reset. The master trip relay shall be operated by the following functions: Buszone The master trip relay shall operate both main and back up trip coils. The circuit breaker close circuit shall be interlocked with the Master trip relay normally closed contact. The master trip relay shall be energised from the main trip coil DC supply. See Figure 2.1. 10.4 Main Protection The following protection shall be deemed to be the main protection: Feeder differential

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The power supplies of the main protection shall be energised from the main trip coil supply. 10.5 Back Up Protection The following protection shall be deemed to be the back up protection: IDMT overcurrent IDMT earth fault The power supplies of the back up protection shall be energised from the back up trip coil supply. 10.6 HV Buszone The buszone protection shall trip the master trip relay and the HV back up trip coil directly. Each trip destination shall be sourced from a separate suitably rated output contact. 10.7 Breaker Fail Breaker fail functionality shall be included on panels at substations that are equipped with buszone and breaker fail protection. The breaker fail functionality shall be initiated from all the protection functions and be supervised by a current pickup. The breaker fail functionality can reside in any of the protection relays. A breaker fail initiate isolation link shall be fitted on the relay panel. 10.8 Auto Reclose The panel shall have auto reclose functionality. The auto reclose functionality should ideally reside in the back-up protection relay. The following protection functions shall initiate auto reclose:

Feeder Differential 10.9 Block Diagram See Figure 10.1 for a typical feeder - type 1E protection block diagram.

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Figure 10.1 – HV Feeder Protection Type 1e 11. Feeder Protection – Type 2 (Fig. 11.1) 11.1 Basic The scheme relates to a HV feeder having a feeder breaker on only one end. Isolation on the other end is achieved by operating a transformer and bus section HV breaker. The basic scheme shall consist of feeder differential protection, IDMT overcurrent, IDMT earth fault and directional overcurrent. The IDMT overcurrent and earth fault shall be a separate relay from that of the line

differential relay. The bus section and transformer CT’s that are used for feeder differential shall either

be summated in an external summation CT or fed into a two CT input feeder differential relay.

The feeder differential relay shall reside on the transformer HV relay panel. The transformer protection will be a typical transformer protection scheme (See

section 2) with the addition of a feeder differential relay and a MV directional overcurrent relay.

The MV directional overcurrent relay shall reside on the transformer MV relay chamber.

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

HV Relay Panel

Close Coil

Buszone

Feeder Differential

Master Trip

MTR TCS-M TCS-B

Main Zone

Check Zone

Auto Reclose

HV Buszone Panel

1200/1000/800/ 600/400/200/1 Class TPS

1200/1000/800/ 600/400/200/1 Class 10P10 15VA

Breaker Fail

1200/1 Class TPS

1200/1 Class TPS


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The feeder protection scheme at the feeder breaker end will be a typical feeder protection scheme (See section 10).

The bus section protection will be a typical bus section scheme (See section 13). 11.2 Minimum tripping requirements 11.2.1 Feeder Differential Protection Feeder Breaker: It is required to operate the main trip coil directly. Transformer Breaker: It is required to operate the main trip coil directly. Bus section Breaker: It is required to operate the main trip coil directly. 11.2.4 MV directional overcurrent It is required to operate the Transformer MV back up trip coil and Transformer HV back up trip coil directly and to operate the master trip relay. Each trip destination shall be sourced from a separate suitably rated output contact. Note: If protection relays have extra output contacts, extra tripping to alternate trip coils shall be used. 11.3 Block Diagram See Figure 11.1 for a typical feeder - type 2 protection block diagram.

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Figure 11.1 – HV Feeder Protection Type 2

Directional O/C

Fdr Differential


Main Trip Coil

B/U Trip Coil

Master Trip Relay


MTR TCS-M TCS-B

Close Coil

HV Transformer Relay Panel

MV Transformer Relay Chamber

TCS-M TCS-B

Close Coil

See Feeder Protection – Type 1E for details of feeder protection (Section 10)

See Transformer Protection – Type 1 for details of transformer protection (Section 2)

See Bussection Protection – Type 1A for details of bussection

1200/1000/800/ 600/400/200/1 Class TPS

1200/1000/800/ 600/400/200/1 Class TPS

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12. Feeder Protection – Type 3 (Fig. 12.1) 12.1 Basic The scheme relates to a typical HV feeder protection scheme. The only difference to the Type 1 protection scheme is the addition of the busbar protection tripping and the transformer tripping. 12.2 Minimum tripping requirements 12.3 Busbar Protection The busbar protection shall trip the back up trip coil directly. 12.4 Block Diagram See Figure 12.1 for a typical feeder - type 3 protection block diagram.

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Figure 12.1 – HV Feeder Protection Type 3


Feeder HV Relay Panel

Close Coil

Busbar Prot

TX -MTR

TCS-M TCS-B

Transformer HV Relay Panel

1200/1000/800/ 600/400/200/1 Class TPS

See Feeder Protection – Type 1E for details of feeder protection (Section 10)

See Transformer Protection – Type 2b for details of transformer protection (Section 3)


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13. Buscoupler / Bussection Protection – Type 1 (Fig. 13.1) 13.1 Basic The scheme relates to a typical HV buscoupler / bussection protection scheme. The basic scheme shall consist of IDMT overcurrent and IDMT earth fault. 13.2 Minimum tripping requirements 13.2.1 IDMT overcurrent It is required to operate the main and back up trip coil directly. 13.2.2 IDMT earth fault It is required to operate the main and back up trip coil directly. 13.3 Master trip relay The master trip relay shall be a flip-flop latching type relay that will be electrically reset by operating a push button on the protection panel or be hand reset. The master trip relay shall be operated by the following functions: Buszone The master trip relay shall operate both main and back up trip coils. The circuit breaker close circuit shall be interlocked with the Master trip relay normally closed contact. The master trip relay shall be energised from the main trip coil DC supply. See Figure 2.1. 13.4 Main Protection The following protection shall be deemed to be the main protection: IDMT overcurrent IDMT earth fault The power supplies of the main protection shall be energised from the main trip coil supply. 13.5 HV Buszone The buszone protection shall trip the master trip relay and the HV back up trip coil directly. Each trip destination shall be sourced from a separate suitably rated output contact.

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13.6 Breaker Fail Breaker fail functionality shall be included on panels at substations that are equipped with buszone and breaker fail protection. The breaker fail functionality shall be initiated from all the protection functions and be supervised by a current pickup. The breaker fail functionality can reside in any of the protection relays. A breaker fail initiate isolation link shall be fitted on the relay panel. 13.7 Block Diagram See Figure 13.1 for a typical Buscoupler / Bussection – type 1 protection block diagram. Figure 13.1 – HV Bus Section / Bus Coupler Type 1

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

HV Relay Panel

Close Coil

Buszone

Master Trip

MTR TCS-M TCS-B

Main Zone

Main Zone

HV Buszone Panel

HV Buszone Panel

1200/1000/800/ 600/400/200/1 Class 10P10 15VA

1200/1 Class TPS

1200/1 Class TPS

Breaker Fail

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14. Buscoupler / Bussection Protection – Type 2 14.1 Basic The scheme relates to a HV bussection protection scheme used to isolate the HV to a transformer described in Transformer Protection - Type 2a. The basic scheme shall consist of IDMT overcurrent and IDMT earth fault. 14.2 Minimum tripping requirements 14.2.1 IDMT overcurrent It is required to operate the main and back up trip coil directly. 14.2.2 IDMT earth fault It is required to operate the main and back up trip coil directly. 14.3 Main Protection The following protection shall be deemed to be the main protection: IDMT overcurrent IDMT earth fault The power supplies of the main protection shall be energised from the main trip coil supply. 14.4 Block Diagram See Figure 14.1 for a typical Buscoupler / Bussection – type 2 protection block diagram.

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Figure 14.1 – HV Bus Section / Bus Coupler Type 2

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

HV Relay Panel

Close Coil TX 1 MTR TCS-M TCS-B

Busbar Protection

Transformer 1 HV Relay Panel

1200/1000/800/ 600/400/200/1 Class 10P10 15VA

Busbar Protection

Transformer 2 HV Relay Panel

1200/1000/800/ 600/400/200/1 Class TPS

1200/1000/800/ 600/400/200/1 Class TPS

See Transformer Protection – Type 2b for details of transformer protection (Section 3)

See Transformer Protection – Type 2a for details of transformer protection (Section 3)

TX 2 MTR

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15. Buscoupler / Bussection Protection – Type 3 (Fig. 15.1) 15.1 Basic The scheme relates to a typical MV buscoupler / bussection protection scheme. The basic scheme shall consist of IDMT overcurrent and IDMT earth fault. 15.2 Minimum tripping requirements 15.2.1 IDMT overcurrent It is required to operate the main and back up trip coil directly. 15.2.2 IDMT earth fault It is required to operate the main and back up trip coil directly. 15.3 Main Protection The following protection shall be deemed to be the main protection: IDMT overcurrent IDMT earth fault The power supplies of the main protection shall be energised from the main trip coil supply. 15.4 Block Diagram See Figure 15.1 for a typical Buscoupler / Bussection – type 3 protection block diagram. Figure 15.1 - MV Bus Section / Bus Coupler Type 3

Main Trip Coil

B/U Trip Coil

IDMT O/C &E/F

MV Relay Chamber


Class 10P10 2000/1000/1 15VA

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74

16. MV Arc Detection Protection All new MV metal clad switchboards shall be fitted with Arc detection protection. Drawings for MV switch boards shall be considered incomplete if the Arc Detection Protection drawings are excluded from drawing submissions. Figures 16.1 (single busbar ac and dc input/supply circuitry), 16.2 (single busbar tripping circuitry) and 16.3 (double busbar input and tripping circuitry) displays the general concepts that should be applied to single and double busbar boards respectively. At the time of compiling this Code of Practice, the standard practice in the Metro was for double busbar MV panels to be used on 11 kV (and below) injection substations and the feeders are run with normal open points, i.e. the MV distribution network is not run in parallel. The only supply to the busbars is therefore from the transformer panels. This practice could change, and recently there are a few networks in the Uitenhage area that operates in parallel. The 22 kV boards are built from single busbar panels and the 22 kV distribution network is generally run without normal open points, i.e. in parallel. As a result, most feeders connected to 22 kV busbars, are potentially in-feeds to the busbars. As a result, isolation of the remote end of feeders become necessary, as isolation of the local breakers only, may not clear e.g. CT chamber arcs. 16.1 Operating Principle Current AND light will be shared for each zone. Double busbar boards shall comprise only a single zone. Single busbar boards shall have a zone per bus section. Isolating the remote side of all possible in-feeds to the MV busbars is essential . (An arc in the CT chamber will not be cleared if only the local breaker of an in-feed is tripped.) Should the latter be impossible (e.g. when no communication medium is available to isolate the remote end of feeders), then only 1 zone must be established. The arc detection protection shall trip, via separate output contacts, the local incomer directly as well as the incomer master trip relay. The arc detection protection must trip a hand reset master trip relay on the incomers so as to prevent inadvertent closing from SCADA. The arc detection relays shall also trip the remote ends of all possible in-feeds into the busbars via MTR’s that would prevent re-energising via SCADA of the tripped breaker. 16.2 Arc Master Relays Each feeder supplying the board under normal operating conditions (termed incomers), shall be fitted with an Arc Master Relay.

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The relay shall be auxiliary supplied from the back-up tripping supply that originates from J3, J4. 16.3 AC supply to the Arc Master Relay Where supply to the board is in the form of a step down transformer, arc detection shall be supervised by an earth fault pick up from the low voltage neutral earth of the transformer. (See fig 16.1 and 16.2). Where no step down transformer is applicable, arc detection protection tripping shall be supervised by an overcurrent and earth fault pick up element i.e the arc detection master shall be so connected so as to sense phase as well as earth fault current. 16.4 Master Trip Relays (MTR’s) Traditionally the Metro’s 11 kV network has been run with normal open points on feeders, with no feeder differential relays applied to these feeders where they run between distribution substations. On these systems, back-feed via feeders is not possible and generally only the incomers AND their remote supply (often the HV side of a step-down transformer) need isolation and locking out via Master Trip Relays. Currently there is a tendency towards running these circuits closed and fitting them with feeder differential relays between distribution substations. Where this is done, it may become possible for a feeder to supply the board (from a remote substation) when the transformer incomers only are isolated. Each feeder needs therefore now fitted with a MTR that will trip the feeder and lock it out. The MTR’s of feeders are operated by the Arc Master Relays as indicated in figures 16.1 and 16.2. The remote (supply) side of the feeders also need to be isolated via the feeder differential relays. The Arc Master Relays (AMR’s) could use the DC supply of the panel where the AMR is installed, to operate the MTR’s in other panels in order to save on bus wiring. However, the MTR in the high voltage panel associated with the panel where the AMR sits, should be operated by voltage free contact. See drawings. 16.5 Legend for Drawings 16.1 and 16.2 C = CT chamber light sensor U = Upper busbar light sensor L = Lower bb light sensor (double busbar board) or busbar light sensor (single

busbar board) MTR = Master Trip Relay RR = Repeat Relay

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LEFT BLANK

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RR

C

B

Trfr Incomer 2

U

L

ARC SLAVE

L

B

-DC

ARC MASTER+DC

B

B

LL

C

Feeder 1

B

ARC SLAVE

+DC

AM

L

C

BRR

CC

Trfr Incomer 1

Feeder 2 RR

Fig 16.1 - AC, DC & Sensor inputs (single busbar)

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RR

-DC

+DC

Trfr Incomer 2

MTR

MTR

-DC

AM

+DC

MTRMTR

HV Panel 1

MTR

Remote Substation

Fdr Diff Relay

MTR

Feeder 1

-

+DC

AM

RR

Fig 16.1

MTR

+DC

-DC

+DC

-DC

Feeder 2

Trfr Incomer 1

BF BFBU-P BU-P

Bus wired to all MTR’s in the same zone.

Note 1 Cross tripping only applies where there is one zone only.

Note 1

Note 1

BF BFBU-P BU-P

HV Panel 2 Note 2 The ideal would have been to wire voltage free contacts from the AM to other panels. However, due tothe limited number of contacts available and also to limit the number of buswires, this scheme is neatest.

Note 3 The Bus Section should not get DC supplies from 2 different panels in parallel. Hence the need for voltage free contacts to the BS.

Note 2Note 3

Bus Section

Fig. 16.2 - The arc protection tripping scheme combined with BF inputs. (Single busbar)

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MTR

MTR

MTR

HV Panel

Feeder 2

-DC

MTR

+DC

C

B

UU

L

C

B

Trfr Incomer 1

+DC

ARC MASTER

RR

Remote Substation

MTR

U

L

B

C

ARC SLAVE

U

L

B

ARC SLAVE

Fig. 16.2

RR

L

Feeder 1

C

Cross tripping from other arc Master

Cross tripping from other arc Master

Fig. 16.3 – Arc protection scheme for double busbar

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LEFT BLANK

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82

17. Buszone Protection See figure 17.1 below. Each zone shall have a separate high impedance numerical differential relay. The scheme shall have “CT Open Circuit” detection. The scheme philosophy shall include a check zone. Each circuit shall have main and check zone CT test blocks. Busstrip / Breaker fail functionality shall be included on the buszone panel. Each zone of the scheme shall be provided with a switch with the following functions: normal operation, busstrip protection off, buszone protection off, busstrip and buszone protection switched off. The buszone scheme shall trip both the Master Trip Relay and the back trip coil (directly) of the individual bays. The following luminous indicating lamps shall be provided on the bus zone panels: Main Zone BZ on – Red Main Zone BF on – Red Main Zone CT faulty – Red Reserve Zone BZ on – Red Reserve Zone BF on – Red Reserve Zone CT faulty – Red Check Zone CT faulty – Red

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59

87

Fdr 3 connected to main BB ? (Use BB isolator aux contact to decide)

Feeder 2 connected to The Main BB ?

Fdr 1 connected tothe Main BB ?

CPU

87

59

CPU

87

59

Fdr 3 connected tothe Reserve BB ?

Fdr 2 connected to the Reserve BB ?

Fdr 1 connected tothe Reserve BB?

Note 1

M-1 M-2 M-3

Main BB

Reserve BB

R-1 R-2 R-3

M-4

R-4

1234

1 = off 2 = normal3 = BF off4 = BZ off

+DC Supply

Note 1 Type G auxiliary contacts (Main and Reserve). It would also be acceptable to arrange the G contacts as inputs into the relays with AND logic to the trip contacts to create BF:

High Impedance Relay

To rest of the logic circuit

Protection Relay (BF)

G aux contact

Note 2 :These contacts shall be 2 x type N contacts series, i.e. 1 x from Main and 1 x from Res BB. The earth sits in YMK.

Note 2

Note 3

Note 3 :Type G contacts. In case the isolator cam close from 2 directions, e.g. PASS units, type G shall apply in both directions, i.e. the aux contact shall close prior to the main contact in either direction. The contact indicated shall comprise 2 contacts in parallel.

Note 4: These contacts should latch if there is no Check Zone MTR. And if they latch, you need a reset input.

Note 4

Note 5

Note 5 : Should the Main and Reserve High Impedance Relays have sufficient number of contacts, the MTR could be done away with. As the panels these contacts go to, would already have MTR’s.

Note 6: G type contacts. See note 3 for detail.

High Impedance Relay Reserve Zone

High Impedance Relay Main Zone

- DC Supply

Fdr 3 connected to main BB ? (Use BB iso aux contacts to decide)

MTR or Tripping Main

Fdr 3 connected to Res BB?

MTR or Tripping Res

Trip contacts to Fdr 3 (ditto for other fdrs). Each feeder must have 2x “sets” of contacts. One trips MTR of the feeder. One trips back-up trip coil of feeder directly.

High Impedance Relay Check Zone

Fig. 17.1

Trip Contacts

Protection Relay(s)

Note 6

Breaker Fail

Check Zone Operated

Reset

Reset

Bus Zone Panel(s)

Reset

TB

TB TB

TB

TB

TB

TB

TB

TB TBTB

TB

TB

TB

TB

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18. Remote Tap Change Control Panels 18.1 Basic The following is to clarify the design and layout of remote tap change control panels. Two schemes are used by the NMMM at present, i.e. the Master/Follower scheme and the circulating current scheme. All new schemes are specified as circulating current schemes. Figure 18.1 shows the basic layout of the control panel for a circulating current scheme. Figure 18.2 shows a conceptual schematic diagram for a circulating current scheme. Figure 18.3 shows a conceptual schematic diagram of the manual/auto control circuit and supervisory control circuit. Figure 18.4 depicts the alarm annunciator and the applicable alarms. Figure 18.1

Supervisory ON/OFF

Alarm Annunciator

Manual / Auto Raise / Lower

Tap Change In progress

Drive Mech In local

Manual Auto

Lamp Test Pushbutton

Voltmeter Tap Position Indicator

Voltage Regulating Relay

VT Test Block

AC Supply Isolator

CT Test Block

Reset Pushbutton

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Figure 18.2

Drive Mech

Remote Local

Supervisory Raise

Supervisory Lower


Raise

Lower

Raise Lower

Raise Aux

Lower Aux

Manual / Auto Electrical Set/Reset Relay

Supervisory Selector Switch

On Off

Raise / Lower Selector Switch

Raise Aux

Lower Aux

Tap Change Not Commenced Relay

Tap Change Not Commenced Timer

Drive Mech

Note: If the Voltage Regulating Relay has a Local/Remote function on the fascia, it must be disabled and defaulted to remote.

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Figure 18.3 Figure 18.4

Manual / Auto Electrical Set/Reset Relay

Manual / Auto Selector Switch

Manual Auto N

M

A

Supervisory Selector Switch

On Off

RTU

Supervisory Auto Select

Supervisory Manual Select

AC Supply Fail

VT Supply Fail

Tap Change Not Commenced

Parallel Operation Error

Voltage Regulating Relay Fail

High Circulating Current

W3

W12

W13

Supervisory Tap Position Lower

Supervisory Tap Position Raise

W10

W11

Supervisory Raise

Supervisory Lower

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18.2 Alarm annunciator The following alarms shall be marshalled to the alarm annunciator: AC supply fail VT supply fail

Tap change not commenced Parallel operation error Voltage regulating relay fail High circulating current 18.3 Lamp indications The following statuses shall be marshalled to lamp indicators: Tap change in progress - white Drive mech in local - amber Manual – white Auto – white 18.4 SCADA alarms The following shall be commoned as a Transformer “B” Alarm (X600,X701): Parallel operation error

Taps not complete VT supply fail

Tap change not commenced AC supply fail MCB trip Voltage regulating relay fail See PEE 101 for the SCADA interface requirements. 18.5 SCADA statuses The following SCADA statuses shall be included: Supervisory selector ON (X29,X40) Supervisory selector OFF (X29,X41) Manual (X29,X42) Auto (X29,X43)

Local Transformer Drive Mech (X29,X34) Remote Transformer Drive Mech (X29,X37)

See PEE 101 for the SCADA interface requirements.

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18.6 SCADA controls The following SCADA controls shall be included: Auto Select (W3,W12) Manual Select (W3,W13) Tap position raise (W3,W10) Tap position lower (W3,W11) See PEE 101 for the SCADA interface requirements. 18.7 AC supply Each Remote Tap Change Control Panel shall have a separate AC supply from the AC Distribution Board. See NMMM drawing YA000072 for complete details. See figure 18.5 for a typical AC supply layout. Figure 18.5

AC Distribution Board

Isolator

AC Supply Fail Relay

MCB MCB

MCB

Tap Change Drive Mechanism

Remote Tap Change Control Panel

Control Supply

Heater

Transformer Marshalling Kiosk

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18.8 VT supply See figure 18.6 for a typical VT supply layout. Figure 18.6 18.9 Tap Position Indicator In the event of the voltage regulating relay having tap position indication, the discrete tap position indicator can be omitted from the panel layout. 18.10 VT input The VT input to the voltage regulating relay shall be connected across the white and blue phases of the VT. 18.11 CT input The CT input to the voltage regulating relay shall be connected to the white phase CT. 18.12 Breaker Statuses When the voltage regulation relay needs breaker statuses e.g. the a-eberle relay, only the LV breaker statuses need to be wired in. All the transformer LV incomers, LV bussections and LV buscouplers shall be wired in. This allows the voltage regulation relay to decide which transformers are in parallel. In the case of the A-eberle relay a background program must be loaded which disallows the relay algorithm to use a transformers parameters when the current through the

Transformer Relay Chamber

MCB

VT Supply Fail Relay

Remote Tap Change Control Panel


MCB

PK2 Test Block

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transformer falls below a preset value e.g. when the HV breaker is open while the LV breaker is still closed.

Rev 10 – 15 Sep 2010

92

Modifications: Rev 6: Added CT information – Pg 13&14 Added Annexure A Rev 7: Paragraph 1.2 and fig. 1.1 changed to reflect the DC supply jumpered externally from panel to panel as oppose to being bus-wired as previously. Paragraph 1.14 add first sentence. Paragraph 16 changed. Figures 16.1 and 16.2 added. Paragraph 17 changed. Figure 17.1 added. Rev 8: Various sentences added to paragraph 14.1. Various minor changes to Fig. 17.1 Luminous indicators added to paragraph 17. Add the second paragraph to clause 1.8. Rev 9: Fig 17.1 changed to reflect CT test blocks. Par 1.14 p16 changed to also include breaker fail or breaker fail initiate. Fig 1.2 changed to reflect jumpered AC supply as opposed to bus wired AC supply. 2 x F contacts added to clause 1.24 as apparently this is the contact to be used for voltage selection. 1 CT circuit was added under Fig. 1.11 – 3150 A feeder 2 CT circuits were added under Fig. 1.12 Changes being considered. CT terminals: Should they be changed to Entrelec M10/10RS?? Was recommended by Frik Smit of ABB. Rev 10 – 15 Sep 2010 The AC and DC distribution drawings changed to reflect separate supply (AC and DC) cables from the DB boards for each panel in a HV control board. For MV boards, only a

Rev 10 – 15 Sep 2010

93

single cable is still run from the DB boards. The AC and DC supplies are then looped at the rear of the panel. Fig 1.6 (Rev 9) changed. Fig 1.8 (Rev 9) changed. New clause 1.25. New Fig. 1.23. Par 1.2 changed. Par. 2.9 (Breaker fail) changed to ask breaker fail to reside in the back-up protection relay. Par. 4.11 changed. Par 10.1 changed. Figures 16.1 and 16.2 (Rev 9) changed to Figures 16.1, 16.2 and 16.3.

Rev 10 – 15 Sep 2010

94

Annexure A CT arrangement for ABB PASS Unit Buscoupler / Bussection C1,5 – 1200/1 Class TPS C2,4 – 1600/1200/1000/600/400/200/1 Class TPS C3 – 1600/1200/1000/600/400/200/1 Class 10P10 15VA Feeder C1,2 – 1200/1 Class TPS C3,5 – 1600/1200/1000/600/400/200/1 Class TPS C4 – 1600/1200/1000/600/400/200/1 Class 10P10 15VA

C1 C2 C3 C4 C5

C1 C2 C3 C4 C5

Line Side Busbar Side

1 of 1.6 (Section 1)

REV – DRAFT 4 1 MARCH 2002PEE CODE OF PRACTICE NO : 10.1

COMMON RULES FILED-F:\DATA\STANDARDS\COP_GEN\SECT 10 – GENERAL\COP 10.1 – COMMON RULES\Sect 1.doc

SECTION 1

APPLICABLE STANDARDS

The following is a list of some of the more commonly used Statutes, Standards and Codes of Practice for the main topics with regard to the planning, design and operation of electricity networks. 1.1 GENERAL OHS Act : Occupational Health and Safety Act (85 of 1993)

NRS 012 : Cable Terminations and Live Conductors within Air Insulated Enclosures

NRS 034 – 1 : Guidelines for the Provision of Electrical Distribution Networks

NRS 060 : Code of Practice for Clearances for the Safety of Persons

SABS ISO 1461 : Hot Dip Galvanised Coatings on Fabricated Iron and Steel Articles –

Specifications and Test Methods

SABS EN 10240 : Internal and / or external protective coatings for Steel Tubes – Specification for Hot Dip Galvanised Coatings applied in Automatic Plants

SABS 763* : Hot-dip Zinc-coatings (galvanising) * Withdrawn; superseded by SABS ISO 1461 and SABS EN 10240 as above

SABS 1019 : Standard Voltages, Currents and Insulation Levels for Electricity Supply

SABS IEC 60694 : Common Specifications for High Voltage Switchgear and Control Gear Standards

IEC 60071 : Insulation Co-ordination Part 1: Terms, Definitions, Principles and Rules Part 2: Application Guide Part 3: Phase-to-Phase co-ordination Application Guide

IEC 60644 : Insulation Co-ordination for Equipment within Low Voltage Systems

IEC 60865 : Short Circuit Currents – Calculation of Effects

ISO 3 : Preferred Numbers

BS 7354 : Code of Practice for the Design of High Voltage Open-Terminal Stations

SABS 0280 : Overhead Line Design

Section 1




1.2 BUILDING, STRUCTURAL AND CIVIL SABS 0100 : The Structural use of Concrete

Part 1: Design Part 2: Materials and Execution of Work

SABS 0160 : The General Procedures and Loadings to be adopted in the Design of Buildings

SABS 0161 : The Design of Foundations for Buildings

SABS 0162 : The Structural Use of Steel Part 1: Limit states Design of Hot-rolled Steelwork Part 2: Limit states Design of Cold-formed Steelwork Part 3: Allowable Stress Design for Steelwork

SABS 0163 : The Structural Use of Timber Part 1: Limit states Design Part 2: Allowable Stress Design

SABS 0164 : The Structural Use of Masonry Part 1: Un-reinforced Masonry Walling Part 2: Structural Design and Requirements for reinforced and prestressed Masonry

SABS 0249 : Masonry Walling

SABS 0252 : Water Supply and Drainage Installations for Buildings Part 1: Water supply Part 2: Drainage

SABS 0400 : Application of the National Building Regulations

SABS 1200 : Standardised Specifications for Civil Engineering Construction

Part A Part AA Part AB Part AD Part AH Part C Part D Part DA Part DB Part DE Part DK Part DM Part DN Part F Part G Part GA Part GB

: : : : : : : : : : : : : : : : :

General General (Small Works) Engineer’s Office General (Small Dams) General (Structure) Site Clearance Earthworks Earthworks (Small Works) Earthworks (Pipe Trenches) Small Earth Dams Gabions and Pitching Earthworks (Road, Subgrade) Earthworks (Railway Sidings) Piling Concrete (Structural) Concrete (Small Works) Concrete (Ordinary Buildings)

Section 1




Part GE Part GF Part H Part HA Part HB Part HC Part HE Part L Part LB Part LC Part LD Part LE Part LF Part LG Part M Part ME Part MF Part MG Part MH Part MJ Part MK Part MM Part NB

: : : : : : : : : : : : : : : : : : : : : : :

Precast Concrete (Structural) Prestressed Concrete Structural Steelwork Structural Steelwork (Sundry Items) Cladding and Sheeting Corrosion Protection of Structural Steelwork Structural Aluminium Work Medium-Pressure Pipe Lines Bedding (Pipes) Cable Ducts Sewers Stormwater Drainage Erf Connections (Water) Pipe Jacking Road (General) Sub base Base Bituminous Surface Treatment Asphalt Base and Surfacing Segmented Paving Kerbing and Channelling Ancillary Roadworks Railway Slidings (Trackwork)

1.3 EARTHING SABS 0198 : Electric Cables

Part 3 Part 12

SABS 0199 : The Design and Installation of an Earth Electrode

SABS 0200 : Neutral Earthing in Medium Voltage Industrial Power Systems

SABS 0292 : Earthing of Low Voltage Distribution Systems

BS 7430 : Code of Practice for Earthing

IEEE 80 : Guide for Safety in AC Substation Grounding 1.4 TRANSFORMERS NRS 054 : Specification for Large Power Transformers

SABS IEC 60076 : Power Transformers

Part 1: General Part 2: Temperature Rise Requirements Part 3: Insulation Levels and Dielectric Tests Part 4: Tappings and Connections Part 5: Ability to withstand short circuit Part 8: Application Guide

Section 1




IEC 214 : On-load Tap-changers

IEC 542 : Application Guide for On-load Tap-changers

BS 2562 : Cable boxes for Transformers 1.5 CIRCUIT BREAKERS SABS IEC 60056 : High Voltage Alternating current circuit breakers

Part 1: General and Definitions Part 2: Rating Part 3: Design and Construction Part 4: Type Tests and Routine Tests Part 5: Rules for Selection Part 6: Information to be given with enquiries

1.6 DISCONNECTORS NRS 031 : Alternating Current Disconnectors and Earthing Switches for AC Voltages

above 1000 V

SABS IEC 60129 : Alternating Current Disconnectors and Earthing Switches

BS 5253 : AC Disconnectors (isolators) and Earthing Switches of Rated Voltage above 1kV

1.7 BUSHINGS SABS 1036

: Hollow Insulators for use in High Voltage Electrical Equipment

SABS 1037

: High Voltage Electrical Equipment – Standard Transformer Bushings

SABS 1371

: Ceramic Hollow Insulators for Standard Transformer Bushings

SABS IEC 60137

: Insulated Bushings for AC Voltages above 1000V

SABS IEC 60233 : Tests on Hollow Insulators for use in Electrical Equipment 1.8 INSULATORS SABS IEC 60273

: Characteristics of Indoor and Outdoor Post Insulators for Systems with Nominal Voltages greater than 1000V

SABS IEC 61109

: Composite Insulators for AC Overhead Lines with a Nominal Voltage greater than 1000V – Definitions, Test Methods and Acceptable Criteria

IEC 60168

: Tests on Indoor and Outdoor Post Insulators for Systems with Nominal Voltages greater than 1000V

Section 1




1.9 SURGE ARRESTORS NRS 039 : Guide for the Application of Gapless Metal-Oxide Surge Arrestors in

Distribution Systems Part 1: Guide Part 2: Specification

SABS IEC 60099

: Surge Arrestors Part 1: Non-linear Resistor type Gapped Surge Arrestors for AC Systems Part 4: Metal-oxide Surge Arrestors without Gaps for AC Systems

1.10 LIGHTNING PROTECTION SABS 03 : The Protection of Structures against Lightning

SABS IEC 61024 : Protection of Structures against Lightning (all parts)

SABS IEC 61662 : Assessment of the risk of damage due to Lightning 1.11 PROTECTION OF ELECTRICAL EQUIPMENT AGAINST DAMAGING TRANSIENTS NRS 042 : Guide for the Protection of Electronic Equipment against Damaging

Transients

SABS 0123

: The Control of Undesirable Static Electricity

SABS IEC 61312 : Protection against Lightning Electro-magnetic Impulse (all parts) 1.12 HIGH VOLTAGE TESTING SABS IEC 60060

: High Voltage Test Techniques (all four parts)

IEC 60270 : Partial Discharge Measurement 1.13 SECURITY INSTALLATIONS SABS 0222 : Electrical Security Installations

Part 1 Part 2

Section 1




1.14 INSTRUMENT TRANSFORMERS 1.14.1 Current Transformers NRS 029 : Outdoor Type Current Transformers

SABS IEC 60044 : Instrument Transformers

Part 1: Current Transformers

IEC 60044 – 6 : Instrument Transformers Part 6: Requirements for Protective Current Transformers for transient performance (New Class ‘TPS’ replaces old Class ‘X’)

SABS IEC 60185*

: Current Transformers (replaces BS 3938) * withdrawn; superseded by SABS IEC 60044 as above

1.14.2 Voltage Transformers SABS IEC 60044 : Instrument Transformers

Part 2: Inductive Voltage Transformers Part 7: Electronic Voltage Transformer

NRS 030 : Electro-magnetic Voltage Transformers

SABS IEC 60186 : Voltage Transformers (Used for Capacitive Vt’s only) 1.15 BATTERIES SABS 1632

: Part 1: General Information – Definition, Abbreviations and Symbols Part 2: Vented type Stationary Lead Acid Cells and Batteries Part 3: Vented type Prismatic Nichel Cadium Cells and Batteries Part 4: Valve Regulated Type Stationary Lead Acid Cells and Batteries

SABS IEC 896 : Stationary Lead Acid Batteries: General Requirements and Methods of test Part 1: Vented Types Part 2: Valve Regulated Types

Section 1




SECTION 2

CLIMATIC, ATMOSPHERIC AND ENVIRONMENTAL CONDITIONS

References: SABS 1035 : Insulated Bushings

SABS 03 : The Protection of Structures against Lightning

SABS 0160 : The General Procedures and Loadings to be adopted in the Design of

Buildings 2.1 Pollution Level The atmosphere is harsh and corrosive being salt-laden at the sea coast. The pollution level is classified as extreme, as defined by SABS 1035. 2.2 Altitude Altitude : 1000m. 2.3 Temperature Minimum temperature : -5oC Maximum temperature : 40oC Daily Average Temperature : 35oC 2.4 Humidity Minimum : 10% Maximum : 90% 2.5 Wind The regional basic wind speed shall be taken as 40 m/s as listed in SABS 0160. The design wind pressure shall be calculated using the values given in Tables 9.1(a) and 9.1(b) of Section 9. 2.6 Lightning The ground flash density (isokeraunic level) in the area of installation is 0,7 / km2/ year as listed in SABS 03.

Section 2




Although this is a low density for South Africa, severe lightning storms do occur and where applicable, allowance shall be made to protect equipment against lightning damage. 2.7 Ice No provision needs to be made for ice loadings. 2.8 Terrain For design purposes the terrain shall be classified, in terms of SABS 0160, in the categories as set out in Tables 9.1(a) and 9.1(b) of Section 9.

Section 2




SECTION 3

SYSTEM NEUTRAL EARTHING PHILOSOPHY

(NMBM Practice / Requirements)

For further detail on System Neutral Earthing Policy / Practice, see PEE Code of Practice Number 10.3. 3.1 Transformer Transmission Windings (Non Source, Primary Windings) The neutral point for all star connected windings on the higher voltage side (primary) of any transformer will be treated as follows: - Primary operating at any voltage greater than 66kV : Neutral to be solidly earthed (see Note 2)

Primary operating at any voltage up to and including 66kV

: Neutral shall not be earthed

Notes: -

1) The star point of an auto-transformer, operating at 132kV on the higher voltage (primary) side, shall also be solidly earthed.

2) On the NMBM system the neutral points of all 132kV primary (star) windings must be solidly

earthed because these are manufactured with graded insulation. This means that the 132kV circuits all have multiple earthing because they are also earthed at the Eskom feeding end.

3) Only 132kV windings shall have graded insulation. All other windings are to be fully insulated.

This is because 132kV star windings are the only star windings on the NMBM system where the neutral point will always be solidly earthed without exception. The reason for using graded insulation on 132kV windings is purely economic. For windings from about 132kV upwards, a saving of up to approximately 12½% can be realised on the total cost of the transformer by fully grading the insulation.

3.2 Transformer Distribution Windings (Source, Secondary Windings) The neutral point of the lower voltage side (secondary) of all transformer star connected “source” windings on each system will be earthed as follows: -

The neutral point of a 66kV system will be solidly earthed (see also Note 1 under clause 3.1).

The neutral point of a 22kV system will be earthed through a 6,0 ohm resistor (see Note 5).

The neutral point of a 11kV system will be earthed through a 3,2 ohm resistor.

The neutral point of a 6,6kV system will be earthed through a 1,9 ohm resistor.

The neutral point of a 400 volt system will be solidly earthed (see NMBM CoP 2.1).

Section 3




Notes: -

1) A single resistor is used to earth the common coupling point of the neutrals for all of the source transformers feeding any one system.

2) The neutral earthing resistors are set at the ohmic values given above in order to limit earth

fault currents to 2000 amperes.

3) The neutral point of an 11kV / 6,6kV auto transformer shall not be connected to earth. These neutrals must not be earthed because: -

i) solid earthing is unacceptable due to the fact that fault current will not be limited

to a low enough level, and

ii) resistance earthing is not practical due to the fact that neither an 11kV nor a 6,6kV neutral earthing resistor is correctly rated as the auto transformer can feed earth fault current in either direction.

4) The system neutral points above 22kV are solidly earthed because above 22kV the cost of a

neutral earthing resistor becomes uneconomical (see also Notes 2 and 3 under clauses 3.1).

5) An oil-filled NER was installed during 2000 at Perl Road Substation. This was done for economic reasons, as this was the only really cost effective type of resistor available. However, this limits the current to 630 A and has a value of approximately 20,2.

i.e. R = 3

22000 630 20,2 ohm

6) There are no 132 / 66kV star/star or 132 / 22kV star/star transformers on the NMBM system. These are only included in Figure 3.1 for the sake of completeness (see Table 10.1 under clause 10 for a full list of NMBM Standard Transformer Winding Arrangements).

Section 3




FIGURE 3.1

NMBM POWER SYSTEM NEUTRAL EARTHING PHILOSOPHY (Grounding Point Locations)

Section 3




BLANK PAGE

Section 3

NER

Sketch 20




SECTION 4

SHORT-TIME WITHSTAND CURRENT RATINGS AND DURATIONS FOR

ELECTRICAL EQUIPMENT

TABLE 4.1 : MINIMUM NMBM REQUIREMENTS FOR SHORT-TIME RATINGS FOR ELECTRICAL EQUIPMENT

SYSTEM

NOMINAL r.m.s. VOLTAGE, Un

(kV r.m.s)

RATED SHORT-TIME

WITHSTAND CURRENT

(kA)

RATED DURATION

(SECONDS) 6,6 25 3 11 25 3 22 25 3 66 25 3 132 31,5 3 REFERENCE : NRS 031 : 1998 – 2ND EDITION (TABLE 1, PAGE 10)

Notes: -

1) The rated peak withstand current shall be taken as 2,5 times the rated short-time withstand current.

2) Usual NMBM MV design fault levels for switchgear are: -

6.6kV - 250 MVA (21 kA) 11kV - 350 MVA (20 kA)

3) The ultimate design fault level for Chatty Substation is 5 000 MVA.

4) A time duration of 3 seconds has been taken as the minimum NMBM requirement because 3

seconds is specified as the preferred duration for voltages up to and including 132kV in the IEC circuit breaker and disconnector standards.

5) The short-time withstand current ratings have been chosen to allow for system growth and

also so that the various items of equipment will be interchangeable throughout the network for strategic reasons.

6) Regardless of the preferred ratings given in Table 4.1 above, the final responsibility, for

ensuring that equipment ratings are adequate for the fault level at any given point on the system, rests with the individual Project Manager / Engineer.

Section 4




TABLE 4.2: IEC RECOMMENDED CO-ORDINATION OF RATED VALUES FOR RATED VOLTAGES

System Nominal

r.m.s. voltage, Un

(kV)

Rated Short-time withstand Current (r.m.s.)

(kA)

Rated peak withstand

current

(kA)

Rated normal current (r.m.s.)

(A)

6,6

8 12,5

16 25 40

20 32 40 63

100

400 400

- - -

- 630 630 630

-

- - - - -

- 1 250 1 250 1 250 1 250

- -

1 600 1 600 1 600

- - - - -

- - -

2 500 2 500

- - - -

4 000

11

8 12,5

16 25 40 50

20 32 40 63

100 125

400 400

- - - -

- 630 630 630

- -

- - - - - -

- 1 250 1 250 1 250 1 250 1 250

- -

1 600 1 600 1 600 1 600

- - - - - -

- - -

2 500 2 500 2 500

- - - -

4 000 4 000

22

8 12,5

16 25 40

20 32 40 63

100

400 - - - -

630 630 630

- -

- - - - -

1 250 1 250 1 250 1 250

-

- - -

1 600 1 600

- - - - -

- - -

2 500 2 500

- - - -

4 000

66

12,5 16 20

31,5

32 40 50 80

- - - -

- - - -

800 800

- -

1 250 1 250 1 250 1 250

- -

1 600 1 600

- -

2 000 2 000

- - - -

- - - -

132

12,5 20 25

31,5 40 50

32 50 63 80

100 125

800 - - - - -

1 250 1 250 1 250 1 250

- -

- 1 600 1 600 1 600 1 600

-

- 2 000 2 000 2 000 2 000 2 000

- - -

3 150 3 150 3 150

- - - - - -

- - - - - -

- - - - - -

Note: - The co-ordination table is intended to be used as a guide for preferred values and is not mandatory. Therefore, a disconnector or earthing switch with another combination of the rated values is not outside this specification. A reduction of the number of preferred combinations of rated values shown in the table is under consideration.

REFERENCE: SABS IEC 129 : 1984 (TABLES IV AND VI) Notes: - 1) Table 4.2 is only included for convenience and as a rough guide.

Section 4



SECTION 5

CLEARANCES (BASIC ELECTRICAL, WORKING AND SAFETY)

TABLE 5.1 REQUIREMENTS FOR OUTDOOR INSTALLATION CLEARANCES APPLICABLE TO EXPOSED ELECTRICAL EQUIPMENT AND POWER LINES*

(50Oc AND A WIND PRESSURE OF 700Pa) 1 2 3 4 5 6 7 8 9 10

System Nominal

r.m.s Voltage

Un

(kV)

Highest system r.m.s

Voltage

Um

(kV)

Minimum safety

clearance for persons (statutory)

see Note 1

(mm)

Minimum phase-to-

earth operational installation clearance for design see Note 1

(mm)

Minimum phase-to-

phase operational installation clearance for design

(mm)

Minimum Clearances in metres (m) Above ground outside

townships

Above ground in townships

Above roads in

townships, proclaimed

roads outside

townships, railways & tramways

To communication

lines, other power lines or between power lines & cradles

To buildings, poles &

structures not forming

part of power lines

1 1,1 or less - - - 4,9 5,5 6,1 0,6 3,0 6,6 7,2 150 150 200 5,0 5,5 6,2 0,7 3,0 11 12 200 200 270 5,1 5,5 6,3 0,8 3,0 22 24 320 320 430 5,2 5,5 6,4 0,9 3,0 66 72 770 770 1050 5,7 5,7 6,9 1,4 3,2 132 145 1450 1200 1650 6,3 6,3 7,5 2,0 3,8

References: 1. Table 3 of the EMR Regulations of the Occupational Health and Safety Act (85 of 1993) with columns 4 and 5 being taken from Section 4.7.1 of Part 7, Section 1 (Industrial Substations) of Eskom’s distribution Standard.

2. Also see NRS 060 – Code of Practice for Clearances for the Safety of Persons.

* - The clearances in this table are only compulsory for non-insulated conductors, i.e. the minimum clearances do not apply to LV and MV bundle conductor (i.e. because this is insulated).

Section 5

Page 5.1 of 5.12

(Section 5)

PTO - Notes




Notes: -

1) Column 4 gives a minimum phase-to-earth installation clearance. This is the minimum distance to be used for design/construction/operational purposes. There is also a minimum safe approach distance for persons for each system voltage, which is referred to in Table 5.1 of the EMR Regulations as a minimum safety clearance. This is given in column 3 above and is the minimum distance to an energised conductor/terminal that a person may approach with reasonable safety. There is an acceptable safety margin built into these distances to ensure that there will be a low probability of breakdown of the air between the conductor and a person at this distance. In columns 3 and 4 the safety clearances and installation clearances for each of the different voltage levels have the same value except for 132kV, which has a greater safety clearance. It should be noted that the safety clearances are a statutory requirement while the installation clearances (design values) are a matter for each engineer/organisation to decide on. It is merely coincidence that all of these values, except for 132kV, are numerically the same.

2) Regulation ‘15’ of the EMR Regulations of the OHS Act is only concerned with the safety of

persons by placing live conductors out of reach. It is not concerned with equipment or performance of the system. It is concerned with the clearances between a live conductor and another circuit’s conductor or other places that a person may occupy. It does not apply to conductors of the same power line. It does not apply for clearances to insulated systems such as LV ABC, insulated services or MV cables.

3) It is generally accepted that protection of persons from direct contact with energised

conductors may be achieved by one of the following methods: -

Insulation as in the case of a cable

Barriers or enclosures as in the case of indoor switchgear

Obstacles as in the case of substation fencing

Placing out of reach

4) The determination of clearances for specific cases is based on the consideration of an ‘object’ space, which is added to the minimum safety clearance. As an example the clearances given in column 6, minimum clearance to a power line above ground outside townships, is based on an object space of 4,9m. The object in this case is the largest vehicle that will normally pass under the power line. This 4,9m object clearance is added to the minimum safety clearance of 0,3m at 22kV to give the 5,2m clearance for a 22kV power line.

5) Clearances may need to be increased to allow for overhead lines approaching open

transformer bushings (see Table 5.6 and Figure 5.3).

Section 5




TABLE 5.2 (see Dimensions ‘A’ and ‘B’ of Figure 5.1) INSTALLATION CLEARANCES BETWEEN LIVE METAL OF DIFFERENT PHASES AND

BETWEEN LIVE METAL AND EARTH FOR ENCLOSED TERMINATIONS IN AIR (ie CABLE BOXES)

System Nominal

r.m.s. Voltage [Un]

(kV)

System Highest r.m.s.

Voltage [Um]

(kV)

Lightning Impulse

Withstand Voltage

(kVp)

Short Duration Power

Frequency Withstand Voltage

(kV)

Minimum Allowable Installation Clearances

(A) (B)

Phase-Earth (mm)

Phase-phase (mm)

6,6

7,2

60

20

90

90

11

12

75

28

120

120

22

24

125

50

220

220

33

36

170

70

320

320

66

72.5

325

140

630

630

REFERENCE: ABB Instruction Number TPR 2682 2220-1 which is based on the requirements of IEC 76-3-1 and NRS 008.

TABLE 5.3 (see Dimensions ‘A’ and ‘B’ of Figure 5.1) INSTALLATION CLEARANCES BETWEEN LIVE METAL OF DIFFERENT PHASES AND

BETWEEN LIVE METAL AND EARTH FOR ENCLOSED TERMINATIONS IN COMPOUND OR OIL (ie CABLE BOXES)

1 2 3 4 System Nominal

r.m.s. Voltage [Un]

(kV)

Insulating Medium in which

Clearances in Columns 3 and 4 apply

Clearance between Live Metal and Earth

[A]

(mm)

Clearance between Live Metal of

Different Phases

[B]

(mm)

11 Compound 32 45 22 Compound or oil 75 100 33 Compound or oil 100 125

REFERENCE : BS 2562 / 1979 – Cable boxes for transformers

Note: - See NRS 012; Cable Terminations and live conductors within air insulated enclosures; for more detail on Tables 5.2 and 5.3.

Section 5




FIGURE 5.1 INSTALLATION CLEARANCES AND MINIMUM CABLE BENDING RADII FOR

CABLE BOXES (See Tables 5.2, 5.3 and 5.4)

Section 5




TABLE 5.4 MINIMUM CABLE END BOX SIZES TO ALLOW FOR MINIMUM BENDING RADII OF VARIOUS

CABLES. System Nominal Voltage

(kV)

Installation Clearances (mm) (Centre line of terminals to gland plate – see Dimension ‘c’ of Figure 5.1)

Single core cables

(All sizes)

Three core cables up to 95mm² 120 – 185mm² 240 – 400mm²

6,6

350

550

600

650

11

400

600

650

700

22

500

700

750

800

33

650

800

900

950

Reference: ABB Instruction Number TPR 2682 0220-1 which is based on the requirements of IEC 76:3 and NRS 008.

Section 5



TABLE 5.5 (see Figure 5.2 )

SAFE APPROACH DISTANCES FOR AUTHORISED PERSONS AND VERTICAL / HORIZONTAL CLEARANCES BETWEEN OBJECTS AND LIVE SECTIONS OF THE SYSTEM WITHIN PROTECTED AREAS. (I.E. FENCED IN SUSBSTATIONS)

1 2 3 4 5 Nominal r.m.s

system voltage

(kV)

Minimum phase-to-earth operational installation

clearance/safe approach distance for persons

(see Dimension ‘A’ – Fig. 5.2) (mm)

Vertical safety working clearances

(i.e. between live and ground level – see Dimension ‘x’ – Fig.

5.2)

(m)

Horizontal safety working clearances

(see Dimension ‘y’ – Fig.5.2)

(m)

Insulation height (pedestrian access)

see note 1

(m)

6,6

150

2,9

2,3

2,4

11

200

2,9

2,3

2,4

22

320

2,9

2,3

2,4

66

770

3,1

2,5

2,4

132

1 200 (1 450)

3,5

2,9

2,4

Reference: BS 7354: 1990 – Code of Practice for design of high-voltage open-terminal stations.

- See Note 1 of Table 5.2

Notes: -

1) The lowest part of any high voltage insulation should not be less than 2,4m above ground level to provide for pedestrian access, eg. Pedestal insulator base (see BS 7354 – Table 4).

2) Also see NRS 060 – Code of Practice for Clearances for the Safety of Persons.

Section 5

Page 5.6 of 5.12

(Section 5)




FIGURE 5.2 SAFE APPROACH DISTANCES FOR AUTHORISED PERSONS AND VERTICAL /

HORIZONTAL CLEARANCES BETWEEN OBJECTS AND LIVE SECTIONS OF THE SYSTEM WITHIN PROTECTED AREAS i.e. FENCED IN SUBSTATIONS (See Table 5.5)

Section 5




TABLE 5.6 (TO BE READ WITH FIG.5.3)

TYPICAL CLEARANCES FOR LINES AND ELECTRICAL EQUIPMENT AROUND A POWER TRANSFORMER IN ACCORDANCE WITH THE FOREGOING TABLES.

Nominal system r.m.s. voltage; Un

(kV)

Minimum phase-to-earth

operational installation

clearance / safe approach distance

for persons (L in mm)

Minimum vertical working clearance from ground level

to live metal

(see note 2) (mm)

‘X’-Dimension (Horizontal)

(2,5 x L ; but with

a minimum of 3000mm)

(mm)

‘Y’-Dimension (Vertical)

(L + 3000)

(mm)

6,6

150

2 650

3 000

3 150

11

200

2 700

3 000

3 200

22

320

2 820

3 000

3 320

66

770

3 270

3 000

3 770

132

1 200(1 450)

3 700

3 000

4 200

1) Dimension not applicable to standard bushings per se. 2) The minimum distance from the transformer base or ground level to the flange base of a bushing (or

surge arrester) shall be 2 500 mm.

Reference: Eskom Distribution Specification : Large Power Transformers

SCSSCAAD 3 (Table 5, P21) * - Also see Note 1 of Table 5.1

Section 5




FIGURE 5.3

TYPICAL CLEARANCES FROM LINES OF APPROACH FOR EXTERNAL CONNECTIONS TO POWER TRANSFORMERS

Section 5




TABLE 5.7 (See also figure 5.4) GROUND INSTALLATION CLEARANCES FOR LIVE TERMINALS IN AREAS ACCESSIBLE BY UNAUTHORISED PERSONS. (OTHER THAN LINES WHICH ARE COVERED BY TABLE 4.1)

Minimum clearance in meters1 2 3

Maximum rated phase-to-phase r.m.s. voltage; Um.

(kV)

System Nominal r.m.s. Voltage; Un

(kv)

Above ground for equipment on structures

[See Dimension “x” in figure 5] (m)

1.1 or less

1

3,6

7,2

6,6

3,7

12

11

3,9

24

22

4,0

REFERENCE : ESKOM TECHNICAL BULLETIN 99TB - 010

Notes: - 1) While the height of the actual power line itself is specified in the EMR Regulations of the OHS

Act, the case of electrical equipment mounted on power line structures is not. The ‘object space’ for this type of situation and the subsequent overall ground clearances were agreed to as per Table 5.7 between Eskom and the Department of Labour.

2) The clearances given in Table 5.7 are the clearance between the live terminals of the

structure mounted equipment and ground level.

3) Also see NRS 060 – Code of Practice for Clearances for the Safety of Persons.

Section 5




FIGURE 5.4 GROUND INSTALLATION CLEARANCES FOR LIVE TERMINALS IN AREAS

ACCESSIBLE BY UNAUTHORISED PERSONS (See Table 5.7)

Section 5




BLANK PAGE

REV – DRAFT 4 1 MARCH 2002PEE CODE OF PRACTICE NO: 10.1


SECTION 6

STANDARD VOLTAGES AND INSULATION CO-ORDINATION

TABLE 6.1 STANDARD VOLTAGES AND INSULATION CO-ORDINATION FOR NMBM

Highest phase-to-phase voltage for

equipment (r.m.s Value)

Um

(Ref: 1)

(kV)

Nominal phase-to-

phase system rated voltage (r.m.s Value)

Un

(Ref: 1)

(kV)

Rated Lightning Peak Impulse

Withstand Voltage (1,2 / 50 s Wave)

Rated 60 Second Power Frequency

Withstand Voltage (wet and dry) (r.m.s Value)

Minimum Nominal Specific Phase-to-

Earth Creepage Distance

(25mm / kV of Um To Earth, between phases and across

the open circuit breaker contacts

(Ref: 1) (kV)

Across the open

disconnector contacts

(kV)

To Earth, between phases and across

the open circuit breaker contacts

(Ref: 1) (kV)

Across the open

disconnector contacts

(kV)

(Ref: 3 and Notes:

1 and 2)

7,2 6,6 75 86 22 25 180 12 11 95 110 28 32 300 24 22 150 172 50 60 600

72,5 66 350 402 140 160 1800 145* 132* 550 632 230 265 3600

References: 1. SABS 1019: 1985 – Standard Voltages, Currents and Insulation Levels for Electricity Supply. 2. SABS IEC 273: 1990 – Characteristics of Indoor and Outdoor Post Insulators. 3. NRS 031: 1998 – Alternating Current Disconnectors and Earthing Switches for AC Voltages above 1 000V.

Related Standards:

1. SABS IEC 694: 1980 – Common Clauses for High Voltage Switchgear and Control Gear Standards. 2. BS 3297: Part 1 – High Voltage Post Insulators. 3. IEC 71: Part 1 – Insulation Co-ordination – Terms, Definitions, Principles and Rules. 4. IEC 71: Part 2 – Insulation Co-ordination – Application Guide.

* - See Note 3

Section 6

Page 6.1 of 6.2

(Section 6)




Notes: -

1. Creepage Distance Definition: the shortest distance along the surface of an insulator between two conductive parts. Note: - the surface of cement or of any other non-insulating jointing material is not considered as forming part of the creepage distance. If a high resistance coating is applied to parts of the insulating part of an insulator such parts are considered to be effective insulating surfaces and the distance over them is included in the creepage distance. (Ref: IEC Dictionary).

2. 25mm / kV is equivalent to a pollution level rating of EXTREME as per SABS 1035.

3. The reference standards give two insulation level options for the nominal system rated

voltage of 132kV. Namely, 550kV or 650kV for the rated lightning impulse withstand voltage and 230kV or 275kV respectively for the 60 second power frequency rated withstand voltage.

IEC publication 71-1 (Insulation co-ordination) states as follows in Clause 45, “When more than one insulation level is given, the highest level is appropriate for equipment located in systems where the earth fault factor* is higher than 1.4 (see clause 17)”. * - Earth fault factor At a selected location of a three-phase system (generally the point of installation of an equipment) and for a given system configuration, the ratio of the highest r.m.s phase-to-earth power frequency voltage on a sound phase during a fault to earth (affecting one or more phases at any point) to the r.m.s phase-to-earth power frequency voltage, which would be obtained at the selected location without the fault. (Ref: IEC 71-1). Note 3 in clause 17 reads, “If, for all credible system configurations, the zero-sequence reactance is less than three times the positive-sequence reactance and if the zero-sequence resistance does not exceed the positive-sequence reactance, the earth fault factor should not exceed 1.4”. Impedances obtained from Eskom for the Chatty 132kV busbar are as follows: - R X Positive-sequence

2,45678

9,06048

Negative-sequence

2,45678 9,07268

Zero-sequence 0,97574 7,16126 From the values of these impedances it can be seen in terms of clause 17, Note 3 above that the earth fault factor will not exceed 1.4. The lower values of insulation level for the 132kV system voltage have therefore been selected for use as the NMBM standard.

Section 6




SECTION 7

PHASE SEQUENCE

The Port Elizabeth electrical phase sequence is non-standard i.e. R-B-Y-R. Special care must be taken to ensure that instruments which are sensitive to the phase sequence, such as those based on the turning disc principle found in certain meters and relays, are correctly wired for this sequence.

NB! Note: - Although the electrical sequence is R-B-Y-R, the physical order is still always R-Y-B.

Section 7




BLANK PAGE

Section 7




SECTION 8

LEGISLATION COVERING DESIGN AND LAYOUT

The design and layout of equipment installations shall be such that in the operating condition all Regulations of the Occupational Health and Safety Act (85 of 1993), as amended, are fully complied with. The following is an extract from the act: - General duties of employers and self employed persons to persons other than their employees: 9.(1) Every employer shall conduct his undertaking in such a manner as to ensure, as far as is

reasonably practicable, that persons other than those in his employment who may be directly affected by his activities are not thereby exposed to hazards to their health or safety.

9.(2) Every self-employed person shall conduct his undertaking in such a manner as to ensure, as far as reasonably practicable, that he and other persons who may be directly affected by his activities are not thereby exposed to hazards to their health or safety.

General duties of manufacturers and others regarding articles and substances for use at work: 10.(1) Any person who designs, manufactures, imports, sells or supplies any article for use at work

shall ensure, as far as is reasonably practicable, that the article is safe and without risks to health when properly used and that it complies with all prescribed requirements.

10.(2) Any person who erects or installs any article for use at work on or in any premises shall ensure, as far as is reasonably practicable, that nothing about the manner in which it is erected or installed makes it unsafe or creates a risk to health when properly used.

10.(3) Any person who manufactures, imports, sells or supplies any substance for use at work shall:

a) Ensure, as far as is reasonably practicable, that the substance is safe and without risks to health when properly used.

b) Take such steps as may be necessary to ensure that information is available with

regard to the use of the substance at work, the risks to health and safety associated with such substance, the conditions necessary to ensure that the substance will be safe and without risks to health when properly used and the procedures to be followed in the case of an accident involving such substance.

10.(4) Where a person designs, manufactures, imports, sells or supplies an article or substance for

or to another person and that other person undertakes in writing to take specified steps sufficient to ensure, as far as is reasonably practicable, that the article or substance will comply with all prescribed requirements and will be safe and without risks to health when properly used, the undertaking shall have the effect of relieving the first mentioned person from the duty imposed upon him by this section to such an extent as may be reasonable having regard to the terms of the undertaking.

Section 8




BLANK PAGE

Section 8




SECTION 9

SAFETY FACTORS AND OTHER PRINCIPLES APPLICABLE TO THE

STRUCTURAL STRENGTH CALCULATIONS FOR OUTDOOR ELECTRICAL EQUIPMENT AND ASSOCIATED SUPPORT STRUCTURES AND

FOUNDATIONS

References: - Act 85 of 1993 : Occupational Health and Safety Act

SABS 1431 : Weldable Structural Steels

SABS 0160 : The General Procedures and Loadings to be adopted in the Design of

Buildings

SABS 0162 : The Structural Use of Steel (all relevant parts)

SABS 0225 : The Design and Construction of Lighting Masts

SABS 0280 : Code of Practice for Overhead Power Lines for Conditions prevailing in South Africa

BS 5950 (Parts 1-9) : Structural use of Steelwork in Building (parts as applicable to the design in question e.g. specification for materials, rolled and welded sections, design of cold formed thin gauge sections etc.)

BS 7354 : Code of Practice for the design of High Voltage Open Terminal Stations

IEC 865 : Short Circuit Currents – Calculation of Effects 9.1 Atmospheric Conditions The atmospheric conditions described in Section 2 shall apply. 9.2 Maximum Working Load for a Support Structure The assumed maximum working load shall be the combined simultaneous loading due to short-circuit current, wind loading, dead weight and conductor tension. 9.3 Short-Circuit Forces Short-circuit forces shall be determined in accordance with the latest revision of IEC 865. 9.4 Wind Forces The wind pressure and force coefficients shall be calculated using Tables 9.1(a) and 9.1(b) on pages 9.3 and 9.4.

Section 9




9.5 Dead Weight for a Support Structure / Foundation The dead weight shall be the vertical loading of the conductors, insulators and equipment supported by the structures and the structures themselves. 9.6 Conductor Tension Loading on Substation Yard Structures The tensioning load of both substation yard conductors and incoming line conductors shall be considered. The reference temperature to be used for maximum tension conditions is –5oC. In the absence of detail on the incoming lines (between the termination tower and the landing gantry), the every day temperature (15oC) tension of each incoming conductor (including earth wire) shall be assumed as 4 500 Newtons. Landing gantries shall be able to accommodate a variation in approach angle of up to 30o laterally and 20o vertically. 9.7 Safety Factors As a minimum requirement, the safety factors prescribed by the Electrical Machinery Regulations, of the OHS – Act, shall be used, as shown in Table 9.2 on page 9.5. Where it is considered appropriate to use design conditions set out in any other Codes, which are at variance with the OHS Act, a relaxation of the OHS Act design conditions will have to be obtained from the Chief Inspector of Machinery. Alternative design conditions might provide less stringent design criteria, but will also result in a reduction of the associated safety margins. Whether the reduction is significant, requires a professional judgement by a competent person, as defined in the OHS Act. The clamps / connectors shall be able to withstand all design forces with a safety factor of 2,5. No slipping shall occur at this force. 9.8 General The design of the structures shall be such that under the assumed maximum working loads, the deflection in the structures will not exceed the limits as specified by SABS 0160 and SABS 0162, nor shall this deflection disturb the alignment of the apparatus supported. The ratio of unsupported length of compression members to their least radius of gyration shall not exceed 120 for main members or 200 for bracing members. The calculated tension / compression stress of any member of the completed structure resulting from the assumed maximum working load shall not exceed 40% of the elastic limit / crippling strength of that member (i.e. safety factor of 2,5).

Section 9



TABLE 9.1(a) – SUMMARY OF MINIMUM ALLOWABLE WIND LOADING PARAMETERS FOR ELECTRICAL STRUCTURES IN NMBM AREA

Structure

Type

Type of Structure

(Description)

*RBWS

(V) m/s

Mean Return

Period (yrs)

Mean Return

Factor (kr)

Terrain

Category

Structure

Class

Altitude Factor

(kp)

Windspeed Multiplier

(kz)

Free Stream

Velocity Pressure (qz) in

N/m2

Velocity Pressure

values in N/m2 (Pa) to be used

(qz) 1

Single Storey Building up to 5m high (Substations)

40

50

1

2

A and B

0.6kp0.56

0.92

kp x (kz x V x kr)2

791.7 / 758.37

2

Boundary walls not exceeding 2.7m above ground level

40

50

1

2

B

0.6kp0.56

0.92

kp x (kz x V x kr)2

758.37

3

Lattice Steel support structures inside substation yards up to 5m high

40

50

1

2

B

0.6kp0.56

0.92

kp x (kz x V x kr)2

758.37

4

I & H beam support structures inside substation yards up to 5m high

40

50

1

2

B

0.6kp0.56

0.92

kp x (kz x V x kr)2

758.37

5

Round, hexagonal and octahedral single pole towers for transmission lines up to 50m high

40

50

1

2

A

0.6kp0.56

1.16

kp x (kz x V x kr)2

1205.65

6

Lattice steel towers for transmission lines up to 50m high

40

100

1.05

1

B

0.6kp0.56

1.21

kp x (kz x V x kr)2

1446.29

7

Lightning masts inside substation yard up to 15m high (lattice structure)

40

50

1

2

B

0.6kp0.56

1.02

kp x (kz x V x kr)2

932.19

8

Security Lighting masts up to 50m high

40

50

1

2

A

0.6kp0.56

1.16

kp x (kz x V x kr)2

1205.65

9

Conductor Spans 2 – 250m

32

n/a

n/a

n/a

n/a

n/a

n/a

1170Pa @ 15oC

0 Pa @ -5oC * RBWS = Regional basic wind speed

Section 9

Page 9.3 of 9.6

(Section 9)



TABLE 9.1(b) – SUMMARY (cont.) OF MINIMUM ALLOWABLE WIND LOADING PARAMETERS FOR ELECTRICAL STRUCTURES IN NMBM AREA

Structure

Type

Type of Structure

(Description)

Applicable Standard

Pressure

Coefficient Cpe

Internal

Pressure Coefficient

Cpi

Force

Coefficient Cf

Gust

Coefficient Cg

Force

(N)

1

Single storey building up to 5m high

SABS 0160 – Tables 6 & 7

-0.7/+0.7

+0.2/+0,02

Cpe – Cpi

Inclusive in kz by virtue of structure class

Cf x qz x Ae

2

Boundary wall not exceeding 2,7m above ground level

SABS 0160 – Table 16

n/a

n/a

1.4

Inclusive in kz by virtue of structure class

Cf x qz x Ae

3

Lattice steel supports inside substation yards up to 5m high

SABS 0160 – Tables 19, 20

& 21

n/a

n/a

Lattice towers-flat members Cf = 2,7 (square plan) and

equilateral = 2. Square towers, rounded members

Cf = 1,7. Equilateral triangular towers rounded

members Cf = 1,1

Inclusive in kz by virtue of

structure class

Cf x qz x Ae

4

I & H beam supports inside substation yards up to 5m high


n/a

n/a

Single frames-flat members Cf = 1,9 and Circular

members Cf = 0,5


structure class

Cf x qz x Ae

5

Round, Hexagonal and Octahedral supports for transmission lines up to 50m high


Table 14 SABS 0160 h = height and

d = diameter of structure

n/a

Cpe – Cpi


structure class

(qz x (sum of Cpex) x Aex from 0 to 180o)

6

Lattice steel supports for transmission lines up to 50m high


n/a

n/a

Lattice square tower-flat

member Cf = 3,4


structure class

Cf x qz x Ae

7

Lightning masts inside substation yard up to 15m high (lattice structure)


n/a

n/a

Lattice tower-flat members Square plan Cf = 2,8 Equilateral Cf = 2,1


structure class

Cf x qz x Ae

8

Security lighting masts up to 50m high


n/a

n/a

Cfz = 1

Cg = 4,36

Cf x qz x Ae x Cg

9

Conductor Spans 2 – 250m

SABS 0280 & OHS Act n/a n/a 0,6 Cg = 0,6 DWP x d x L1 x K x Cg**

** DWP is the design wind pressure, d is the diameter of wire, L1 is the wind span, K is the shape factor = 0,6

Section 9

Page 9.4 of 9.6

(Section 9)



TABLE 9.2 – SUMMARY OF FACTORS OF SAFETY (FoS)

Structure Type

Reference is made to Table 15

Type of Structure

Applicable Code of

Practice

Material Characteristics

Partial Load

Factor of

Safety (FoS)

FoS

% Diff of Partial Load FoS

on OSH Act FoS

Type / Grade

Characteristic Strength Mpa

Ultimate Tensile

Strength (UTS) Mpa

Allowable Mpa

OSH ACT

Type

Tested

UTS

Tension

Bending

Type

Tested

UTS

A – B B x 100

A – C C x 100

A B C 3,4 and 6 Steel Lattice Structures SABS 0162 – 1: 1993 43 (t – 40mm) fy = 250 430 155 165 2.77 2.5 2.5 10.8 10.8

300W (t – 40mm) fy = 300 450/620 185 195 2.43/3.35 2.5 2.5 2.43/3.35 2.43/3.35 5 and 8 Solid Dawn Steel Poles SABS 0162 – 1: 1993 43 (t – 40mm) fy = 250 430 155 165 2.77 2 2.5 38.5 10.8

7 Welded Poles SABS 0162 – 1: 1993 43 (t – 40mm) fy = 250 430 155 165 2.77 2.2 2.5 25.9 10.8

1 and 2

Steel Reinforcement

SABS 0100 – 1: 1992 Mild Steel – Hot

Rolled up to 10mm (t)

fy = 250

430

165

n/a

2.6

2.5

2.5

4

4

High Yield – Hot Rolled up to 10 to

40mm (t)

fy = 450

542

247.5

n/a

2.2

2.5

2.5

-12

-12

9

Stay Wires

SABS 0100 – 1: 1992

Hard drawn steel wire 0 – 12mm (t)

fy = 485

1400/1700

636

n/a

2.2/2.67

2.5

2.5

-12.43/6.8

-12.43/6.8

1 and 2

Reinforced Concrete Spun Poles

SABS 0100 – 1: 1992

Fcu = 30 Mpa*

13.4

30

n/a

n/a

2.24

2.4

3.5

-6.67

-36

1 and 2 Mechanical Reinforced Concrete Structures

SABS 0100 – 1: 1992

Fcu = 30 Mpa*

13.4

30

n/a

n/a

2.24

2.5

3.5

-10.4

-36

1 and 2 Other Concrete Structures

SABS 0100 – 1: 1992

Fcu = 30 Mpa*

13.4

30

n/a

n/a

2.24

2.75

3.75

-18.54

-40.3

9 Wooden Members not continuous loaded

SABS 0163 – 1

Grade 6**

n/a

13.87

3.8

6

3.65

3.5

4.4

4.29

-17.05

9 Wooden continuous Loading***

SABS 0163 - 1

Grade 6**

n/a

13.87

2.55

4

5.48

5.5

6.75

-0.36

-18.87

* Used Fcu as 30 Mpa as an example ** Grade 6 timber used as an example *** Post disaster stability assumed to be 1.5 times acceptable daily risk

Section 9

Page 9.5 of 9.6

(Section 9)




BLANK PAGE

Section 9




SECTION 10

STANDARD TRANSFORMERS

10.1 Matching with Existing Units Unless to be used in parallel with an existing transformer, in which case the new unit shall match the existing unit, all new transformers shall be supplied in accordance with the table given in clause 10.2. 10.2 NMBM Standard Distribution and Transmission Transformer Ratings and Parameters

Section 10



TABLE 10.1 (See Also Figure 10.1)

NMBM STANDARD DISTRIBUTION AND TRANSMISSION TRANSFORMER RATINGS AND PARAMETERS

No.

MVA Rating Nominal Voltages Impedance Vector Group

Taps (See Figure 7)

Losses

Main

Tertiary

Primary kV

SecondarykV

Tertiary kV

Min %

Nominal %

Max %

(e.g. YnaOd1 HV / MV

auto-connected,

Delta tertiary)

No. of Tap

positions

No. of steps

Principal Tap no. (0% Tap position

i.e. Nominal Voltage)

Step value

No. Load (kW)

Load

(kW)

1

150

132

66

15

16,5

YnaO

17

16

5

1¼ %

2

120

132

66

15

16,5

YNaO

17

16

5

1¼ %

3

80

132

66

15

16,5

YNaO

17

16

5

1¼ %

4

63

132

22

15

16

YNynO

17

16

5

1¼ %

5

31,5

132

11

15

16

YNynO

17

16

5

1¼ %

6

40

66

22

10

15

YNynO

17

16

5

1¼ %

7

20

66

11

12

15

YNynO

17

16

5

1¼ %

8

15

66

6,6

12

15

YNynO

17

16

5

1¼ %

9

10

22

11

9

10

YNynO

17

16

5

1¼ %

10

10

22

6,6

9

11

YNynO

17

16

5

1¼ %

11

6

11

6,6

2,5

3,5

YNaO

5

4

Off load 3

2½ %

Section 1

0

Page 10.2 of 10.4

(Section 10)




FIGURE 10.1 STANDARD NMBM TRANSFORMER TAPPING RANGE

SHOWN FOR INCOMING WINDING OF A STEP DOWN TRANSFORMER (See also Table 10.1)

Section 10




BLANK PAGE

Section 10




SECTION 11

SUBSTATION DC SYSTEMS

11.1 Voltage In substations where inter-tripping is used or is likely in the future (including all 132kV and major 66kV substations), the battery voltage should be 110V. In other substations, the voltage shall be 30V. 11.2 Ratings for Batteries The capacity shall be sufficient to maintain the substation standing load such as electronic relays, etc., for a minimum of 12 hours. Example: - For a standing load of 2 amps, the battery shall be of at least 2 * 12 = 24 ampere hour rating. (Can we put in an allowance for each type of panel for the standing load due to electronic relays and other items, or will each case have to be considered separately?) 11.3 Battery Chargers All new battery chargers shall be of the constant voltage type. Where electronic relays are fitted to substations with existing trickle chargers, the chargers shall be replaced with a CVC unit. The charger shall have a current rating such that it can carry the full standing load at the substation and at the same time recharge the batteries in nor more than eight hours. Example: - For a standing load due to electronic relays, etc., of 2 amps, with a battery of 24 ampere hour rating, the current rating of the charger shall be: - Standing Load 2 Recharging load 24/8 = 3 5 amps.

Section 11




BLANK PAGE

Section 11




SECTION 12

PREFERRED NUMBERS / STANDARD SIZES (R.10 Series)

This system of standard sizes was introduced by a French Engineer, Charles Renard, and is variously referred to as theoretical numbers, preferred numbers or Renard numbers. Publication ISO 3 (preferred numbers) sets out a basic series of numbers, which are used throughout all IEC standards as the basis for standard sizes / ratings. (Also see BS 2045). This sequence of numbers is known as the R.10 series, which occurs as follows: - 1,00; 1,25; 1,60; 2,00; 2,50; 3,15; 4,00; 5,00; 6,30; 8,00; 10,00. Any multiple (order of magnitude) to a power of ten, can be assigned to each of these numbers. ISO 3 gives five basic series, of which the R10 is the preferred one, as follows: -

R5 R10 R20 R40 (R80) (Exceptional)

1,00 1,25 1,60 2,00 2,50 3,15 4,00 5,00 6,30 8,00 10,00

5 10

10 10

20 10

40 10

80 10

Theoretical Values

5 10 N 10 10 N etc.

Where N = 0,1,2,3,4,5,6,7, etc.

Section 12




BLANK PAGE

Section 12




SECTION 13

SELECTION OF LIGHTNING ARRESTORS

Introduction Note: - see also NRS 039 Parts 1 and 2, as well as SABS IEC 99-1. Selecting a surge arrestor is based on three factors: -

1. It should discharge minimum current under normal system conditions and under temporary power frequency over-voltage conditions (long duration faults).

2. It should discharge sufficient current under surge conditions (e.g. lightning) to clip the over-

voltage resulting from the surge, to values below the lightning impulse withstand voltage of the equipment protected.

3. The housing (creepage, material, etc.)

Selecting a surge arrestor based on (1) means finding an arrestor with a maximum continuous operating voltage (MCOV) temporary over-voltages (TOV) of the system, should the fault causing the over-voltage last forever. However, power frequency over-voltages are cleared within a pre-defined time. It is therefore not essential for MCOV to be higher than the power frequency over-voltage (TOV), as long as the clearing time of the fault is such to prevent permanent damage to the arrestor. In other words, TOV may exceed MCOV for short time durations. Selection Procedure The following steps should be taken to select the correct surge arrestor for an application: - Step 1 Determine the system’s temporary power frequency over-voltage (TOV)

TOV = (Un x 1,1) / 3 x EFF Note: Um = Un x 1,1. Where

Un = System Line-to-line nominal voltage (e.g. 11, 22, 66, 132kV)

3 = Conversion factor from line voltage to phase voltage

EFF = Earth fault factor

= Assume 1,4 as worst case, for effectively earthed systems (Directly connected System Neutral)

= Assume 1,73 as worst case, for non-effectively earthed systems (Resistance earthed System Neutral)

Section 13




Note on System Earthing Under phase-to-ground fault conditions the voltage on the healthy phases will rise with respect to earth. The voltage to which the healthy phases will rise depends mainly on the impedance of the system neutral earthing (the higher the earth impedance, the higher the voltage rise). A system can be classified as either effectively earthed or non-effectively earthed as per SABS 0200:1985. In the case of an effectively earthed system, the phase-to-ground voltages of the healthy phases will not rise to more than 80% of the rated line-to-line voltage under earth fault conditions. Thus: - Effectively Earthed : U x 0.8 x Un

Non-effectively Earthed : U x 0.8 x Un Where Ux Phase-to-ground voltage on the healthy phases under earth fault conditions

Un Line-to-line voltage under normal conditions

Note: See also Cop 10.3 Neutral Earthing Philosophy. Step 2 If the above (worst scenario) fault is not cleared, the arrestor should have a maximum continuous operating voltage (MCOV) TOV. However, as previously mentioned, the fault is cleared within a pre-defined time and the arrestor could therefore have an MCOV of less than TOV, depending on the fault clearing time. Therefore, MCOV : TOV x 0,8

MCOV : The voltage an arrestor can withstand on a continuous basis with little discharge The value of 0,8 relates to a fault clearing time of 10 seconds. The rated voltage (Ur) of an arrestor defines its capability of withstanding voltages larger than MCOV and is time related. It is also related to MCOV with a factor determined by the material used. Ur : MCOV / 0,8

Ur : Rated Voltage

: A voltage higher than MCOV that the arrestor can withstand (with little discharge) for

short durations Here 0,8 is a value recommended by IEEE C62.11 – 1993. It depends on the design of the arrestor and the materials used in construction. The fact that the above factors are both 0,8 is coincidence. The following should be avoided: - Ur = TOV !

Section 13




Step 3 Determine the TOV withstand capability, Kt (in some text referred to as the TOV strength factor) as follows: - Kt = TOV / Ur From the supplier’s data curve, determine the arrestor survival time in seconds and decide whether the arrestor fulfils our needs in respect of clearing time. Step 4 Providing the result of Step 3 is positive, we have now found an arrestor that will operate satisfactorily under normal or power frequency fault conditions. The next step is to determine the arrestor’s operation under surge conditions. The equipment to be protected will have a lightning impulse withstand voltage referred to as the basic impulse level (BIL) of the equipment. This is the voltage at which equipment will normally be tested in the factory (e.g. 350kV for 66kV systems and 550kV for 132kV systems). The arrestors should be so designed to prevent the voltage on the system from exceeding the BIL of the equipment. The residual voltage of an arrestor (Ures) indicates the remaining voltage on the arrestor in case of a discharge. This voltage is normally defined at the nominal discharge current (In) of the arrestor where it is referred to as the protection level (Upl). This, in turn, has been determined by statistical approach for conditions prevailing in the Republic of South Africa. In = f (lightning density in strikes/km2/year, length of line) In will be taken as 10kA for the NMBM’s transmission network. Ures Ur x 3,3 @ 10kA = Upl. Round this value off up or down to the nearest 5kV. The safety margin (PM) now needs to be determined. PM = ((BIL/Ures) – 1) x 100 And must be at least 20%. It is important to remember that the discharge current could be higher than In. Ures will accordingly be higher (than Upl) when this happens. It is therefore important that the PM should be as big as possible to allow for this scenario. However, there is a definite relationship between Ures (and by implication the safety margin) and Ur. The bigger the safety margin, the lower Ures and the lower Ur. Ur, in turn, should be high enough to fulfil the requirements for arrestor survival time. Safety margins between 50% and 100% are ideal, but not always obtainable. Selecting the correct surge arrestor may therefore need more than one trial as it is a trade-off between operation under normal conditions and operation under surge conditions. Note: - Surge arrestors are installed between phases and earth and are therefore subject to phase voltages and not line voltages.

Vphase = Vline / 3

Section 13




Protection Distances Surge arrestor protection distances depend on the speed of the travelling (surge) wave and can be estimated as follows: - L V/(2 x S) x ((BIL/1,25) – Ures) Where L

= Protection distance in metres including the length of the conductor to the arrestor.

V

= 300m / s (Propagation Velocity).

1,25

= Safety factor between the lightning impulse withstand voltage of the equipment at distance L from arrestor and the surge (lightning) over-voltage.

S = Rate of rise of surge in kV / s.

= 1 550 for wooden pole lines.

= 800 for earthed cross-arm lines. We shall normally use 800kV / s. Ures = residual voltage of arrestor during discharge and is determined as outlined above. EXAMPLE Find a suitable arrestor for a 22kV system. The neutral earthing is non-solid. TOV = ((Un x 1,1) / 3 ) x EFF

= ((22 x 1,1) / 3 x 1,73

= 24kV

MCOV = TOV x 0,8

= 24 x 0,8

= 19,2kV

Ur = MCOV / 0,8

= 19,2 / 0,8

= 24kV

Kt = TOV / Ur

= 24 / 24

= 1

Section 13




Now use the supplier’s curve to determine the survival time (ST) of the arrestor. ST 700 seconds, which is far more than adequate

Now try: - MCOV = TOV x 0,7

= 24 x 0,7

= 18,6kV

Ur = MCOV / 0,8

= 16,8 / 0,8

= 21kV

Kt = TOV / Ur

= 24 / 21

= 1,14

From the supplier’s curve: - ST 0,3 seconds, which is inadequate

Hence choose Ur = 24kV Ures Ur x 3,3 @ 10kA = Upl (Protection Level)

= 24 x 3,3

= 79,2kV

= 80kV @ 10kA

PM = (BIL / Ures – 1) x 100

= ((150 / 80) – 1) x 100

= 87,5% which is OK

L = V / (2 x S) x (BIL / 1,2) – Ures

= 300 / (2 x 800) x ((150 / 1,25) – 80)

= 7 metres providing the cross-arms are earthed

If not then: - L = 3 metres

Section 13




Notes to Designer

The supplier’s curve is not always necessarily available at the time of the tender.

The best will be to assume a value of Kt (probably that of the most often supplied arrestors) and state this clearly in the specification.

This is part of the reason why it is so critical to confirm that the arrestor offered indeed

satisfies our needs.

Section 13




SECTION 14

CABLE LAYING DEPTHS AND TRENCHING DETAILS

FIGURE 14.1 – CABLE TRENCHING TERMINOLOGY

Section 14




FIGURE 14.2 – LV MAINS CABLES UP TO 600 VOLTS

Section 14




FIGURE 14.3 – MV CABLES (6,6 kV, 11 kV and 22 kV)

Section 14




FIGURE 14.4 – HV CABLES (66 kV and 132 kV)

Section 14




FIGURE 14.5 – SERVICE CABLES LAYED IN EXISTING ESTABLISHED ROAD RESERVE (Paved / Tarred)

Section 14




FIGURE 14.6 – SERVICE CABLES LAYED IN EXISTING ESTABLISHED ROAD RESERVE (Gravel / Untarred)

Section 14




FIGURE 14.7 – SERVICE CABLES LAYED IN NEW DEVELOPMENT (Unmade Road)

Section 14




BLANK PAGE

Section 14

of 1 (Amendment Section)

REV – DRAFT 3 15 APRIL 2001PEE CODE OF PRACTICE NUMBER 10.1 – COMMON RULES

FILED-F: \DATA\STANDARDS\COP_GEN\SECT 10 – GENERAL\COP 10.1 – COMMON RULES\Amendment.doc

NELSON MANDELA BAY MUNICIPALITY

ELECTRICITY AND ENERGY DIRECTORATE

PEE CODE OF PRACTICE: NUMBER 10.1

AMENDMENT SHEET [LAST NUMBERED PAGE(S) OF CODE OF PRACTICE]

REV NO

DETAILS

AUTHOR

DATE OF REVISION / ISSUE

Draft 2

Various amendments

BCF

5 July 2000

Draft 3 Split up document

i.e. each section in an individual file

BCF

15 April 2001

Draft 4 General update with detailed corrections to Sections 2,3 and 9

BCF

PG

1 March 2002

COMMON RULES

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REV – DRAFT 1 AUGUST 2013PEE CODE OF PRACTICE NO: 9.1

THE SMALL WIRING OF TRANSMISSION EQUIPMENT AND INSTALLATIONS FILED-F:\DATA\STANDARDS\COP_GEN\SECT 6 – PROTECTION\COP 6.2 – PROTECTION CURVES AND SETTINGS\COP 6.2.doc


DRAFT PEE CODE OF

PRACTICE NUMBER: 9.1

________________

THE SMALL WIRING OF TRANSMISSION EQUIPMENT AND INSTALLATIONS

____________________________

REV – DRAFT 1 AUGUST 2013

of 10



BLANK PAGE

of 10





INDEX TO PEE CODE OF PRACTICE NUMBER 9.1


TABLE OF CONTENTS

PAGE

1. SCOPE 5

2. REFERENCES

3. DEFINITIONS 5

4. DC DISTRIBUTION 6

5. AC DISTRIBUTION 6

6. OUTDOOR YARDS AND MARSHALLING KIOSKS 6

7. MULTI RATIO OUTDOOR CT’s – CONNECTIONS AND NAMEPLATES 6

8. MULTI-CORE CABLE NUMBERING 6

9. TRUNKING 7

10. TERMINAL BLOCKS AND LUGS 7

11. CORE SIZES 8

12. WIRE COLOURS 8

13. CORE NUMBERS OF MULTI-CORE CABLES 8

14. SPARE CORES IN MULTI-CORE CABLES 8

15. NO YARD WIRING ALLOWED 8 16. NO BUS WIRING ALLOWED 8 17. AC AND DC WIRES NOT TO BE MIXED IN SINGLE CABLE 9

18. WIRE MESH SUPPORT FOR OUTDOOR MULTI-CORE CABLES 9

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LIST OF DRAWINGS FORMING PART OF THIS CODE OF PRACTICE Reference is made to drawings in Protection Design Guidelines Rev 10.

AMENDMENTS An Amendment Sheet, giving a record of changes / updates to this Code of Practice, is included as the

last numbered page(s).

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PEE CODE OF PRACTICE NUMBER 9.1


1. SCOPE

This standard covers the following items: The small wiring of ALL electrical equipment used on Transmission Projects. These

include, but is not limited to:

Power Transformer Driving Mechanism; Power Transformer Marshalling Kiosk; Yard Marshalling Kiosk; Remote Tap Change Control Panels; Metal-clad Switchgear; Relay / control panels; The trip/close mechanism compartment of outdoor switchgear;

The distribution of DC supplies from the substation DC distribution board to indoor

equipment and associated outdoor equipment; The distribution of AC supplies from the substation AC distribution board to indoor

equipment and associated outdoor equipment; The use of multi-core cabling between outdoor and indoor equipment, between various

pieces of outdoor equipment and various pieces of indoor equipment; Lugs; Terminal Blocks; The cabling of multi ratio outdoor CT’s to the substation building;

2. REFERENCES

(Future) PEE CoP 6.3 Rev 10 Date unknown

Protection Design Guidelines and References

3. DEFINITIONS

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Small wiring shall include: All DC wiring; All 400 V, 3 phase and 230V, 1 phase AC wiring; All voltage free wiring such as the wiring of a voltage free contact from 1 location to

another; All CT secondary circuits; All indication, control and wiring circuits All trip and close circuits

4. DC DISTRIBUTION

Protection Design Guidelines Rev 10 Fig 1.2 (HV Relay / Control Panels) and Fig 1.1 (Metal-clad Switchgear Board) indicate the principle of the DC distribution at the substation. The key principal is that there will be no yard DC available. The DC supply to outdoor equipment is done from the building’s distribution board via its associated indoor equipment, to outdoors. Double pole MCB’s are used to protect DC circuits and each separate application is protected by its own MCB.

5. AC DISTRIBUTION

Protection Design Guidelines Rev 10 Fig 1.3 indicates the principle of the AC distribution at the substation. The key principal is that there will be no “yard AC” available. The AC supply to outdoor equipment is done from the building’s distribution board via its associated indoor equipment to outdoors.

Double pole MCB’s are used to protect AC circuits and each separate application is protected by its own MCB.

6. OUTDOOR BAYS AND MARSHALLING KIOSKS

Each outdoor bay shall be equipped with its own yard marshalling kiosk. All yard equipment shall be wired to the marshalling kiosk, from where it shall be wired to control equipment in the substation building, i.e. CT’s, disconnector switches, earth switches, circuit breakers and any other equipment that may form part of an outdoor HV bay from time to time. The only exception to the above is the small wiring from outdoor power transformers to its associated indoor equipment. The same shall be directed via the transformer marshalling kiosk as opposed to the yard marshalling kiosk.

7. OUTDOOR CT’S – RATIO’S, CONNECTIONS AND NAMEPLATES

The ratio selection on multi-ratio outdoor CT’s shall be done on the CT’s itself. Hence, from each CT core, only 4 wires shall be wired to the yard marshalling kiosk. In addition to the nameplate on the CT’s, yard marshalling kiosks shall contain weatherproofed nameplates of all CT’s and CT cores wired to it. Bus zone protection CT’s shall be wired directly from the yard marshalling box to the bus-zone protection panel. All other CT’s shall be wired to its own indoor relay panel from where it shall be directed elsewhere if applicable. Unless called for in the Contract Specification, outdoor CT’s shall be self-contained loose standing units. They shall not be installed in other outdoor equipment such as transformers or circuit breakers. The only outdoor CT types that could be installed in other equipment are CT’s for Line Drop Compensation purposes and;

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Circulating Current purposes.

The secondary wiring of these CT’s go to the transformer marshalling kiosk and from there directly to the Tap Change Control Panel and not via the yard marshalling kiosk.

8. MULTI-CORE CABLE NUMBERING

Cables shall be labeled with copper plates punched with the appropriate numbers. The plates shall be attached to the cables with copper wire. The following abbreviations shall be used: BZ = Bus zone protection panel RP = Relay / control panel RTU = SCADA Remote Terminal Unit RTCCP = Remote Tap Change Control Panel YMK = Yard Marshalling Box DM = Outdoor Transformer Driving Mechanism TMK = Outdoor Transformer Marshalling Kiosk The above abbreviations shall be used to indicate the destination of a cable. The number of the cable shall be a unique (unique for that substation) 3-digit number. E.g. a 3rd cable running from the yard marshalling box to the relay panel of a specific bay could have a label running from RP001 to RP999 (e.g. RP153) at the marshalling box. The same cable shall be labeled YMK153 at the relay panel. No other cable in the same substation shall have the number 153. Although, as a general rule, it would not be allowed, a cable running from the marshalling kiosk in one outdoor bay to the relay panel controlling another bay, should also reflect the name of the bay on either side. The name could be abbreviated but should be a clear indication of the real name. E.g. a cable running from the marshalling kiosk of the Grassridge No 1 bay to the Ditchling (indoor) No 1 relay panel at Chatty substation could have the following labeling: At marshalling kiosk: RP001 Ditch01 At relay panel: YMK001 Grass01 The name of the indoor control panel or the outdoor bay shall be punched on the cable label as a second line as indicated above. The omission of a name would mean the cable runs to equipment of the same bay.

9. TRUNKING

The small wiring of any equipment shall be done using suitable sized trunking. Trunking shall never be more than 80% filled. The only wiring that would be allowed outside trunking is wiring going to equipment fitted on a door such as the relays on the door of the relay chamber of metal-clad switchgear. In such cases, the wires shall be neatly bounded together using plastic spring wrap-around. Cloths or cable-ties shall not be allowed.

11. TERMINAL BLOCKS AND LUGS

Wires shall be lugged using hook blade lugs for all terminations. No more than 2 wires shall be terminated on a single termination. Where this is done, the hook blade lugs shall be placed back to back.

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Only the following terminal blocks shall be used: CT circuits: Entrelec M 6/8 RS fitted with centerpiece test plugs Transducer circuits : Klippon SAKT 2 SCADA cables : Entrelec M 6/8 RS All other terminations: Entrelec M 6/8 RS Earth wires: Entrelec D6/8-ST-RS (with drop links)

11. CORE SIZES

CT circuits shall have a minimum size of 2.5 mm². All other same panel wiring shall be minimum 1.5 mm² in size. Where the design (volt drop, continuous or short-time current) demands bigger size cores, the design must obviously take preference. The sizes of cables/wires linking different panels or apparatus (indoor and outdoor) shall be designed to suit the requirements, but shall not be less than 2.5 mm² in size.

12. WIRE COLOURS

Wires shall have the following colors: DC: Grey AC: Black CT’s: Color coded, i.e. red, white and blue

13. CORE NUMBERS OF MULTI-CORE CABLES The following core numbers shall be used as a standard: 4 core 7 core 14 core Cables with a larger core number shall only be considered if the design demands a much larger core number between 2 points. The sole discretion for the approval / rejection of such a request lies with the NMMM Project Manager.

14. SPARE CORES IN MULTI-CORE CABLES A minimum of 4 spare cores shall be allowed between each unique start and end combination except 10 pair cables to SCADA RTU’s.

15. NO YARD WIRING ALLOWED No wiring shall be allowed between the yard marshalling kiosks of 2 different bays. Where such wiring is required, the wiring in respect of each bay shall be done from the yard marshalling kiosk to the relay / control panel of that bay. The necessary wiring shall then be affected between the 2 relay / control panels. Where wiring is required between same outdoor bay equipment, e.g. if a protection design requires the auxiliary switches from 2x busbar disconnectors and a line disconnector of the same bay to be wired in series into the protection scheme, the 3x switches could be connected in series inside the yard marshalling kiosk.

16. BUS WIRING NOT ALLOWED

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Bus wiring between indoor equipment such as metal-clad switchgear or relay / control panels shall be limited as far as possible. Only the following wires shall be bus wired unless prior approval has been obtained from the Employer: DC supplies AC supplies Standby earth fault trips Spring discharged SCADA alarm Arc detection protection wiring

17. AC AND DC WIRES NOT TO BE MIXED IN SINGLE CABLE AC and DC circuits shall not be mixed in a single multi-core cable.

18. WIRE MESH SUPPORT FOR OUTDOOR MULTI-CORE CABLES The exposed section of all multi-core cables in outdoor yards between ground level and entry into gland plates, shall be supported by hot-dipped galvanized wire mesh supports.

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PEE CODE OF PRACTICE : NUMBER 9.1


AMENDMENT SHEET [LAST NUMBERED PAGE(S) OF STANDARD]

REV NO.

DETAILS

AUTHOR


Draft 0

PG 26 April 2005

Draft 1

Aesthetic changes on the first few pages, e.g. the municipal emblem and reference to Directorate instead of Business Unit. Drawings YA000072, YA000073, YA000074, YA000075 deleted and replaced by referencing Fig 1.1, Fig 1.2 and Fig 1.3 of the Protection Design Guidelines and References Rev 10. New paragraph 2 (references) inserted and paragraph numbers following this have changed as a result.

PG August 2013

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REV – DRAFT 8 1 MARCH 2010PEE STANDARD NO: 003

METAL-CLAD SWITCHGEAR UP TO 24kV C:\Users\za00177\Box Sync\My Box (za00177)\MD3719 - BAIC Bulk Supply\Technical_Data\_Received\_NMBM_STD\Std 003 (01-03-2010) Draft Copy.doc


PEE STANDARD NUMBER: 003

________________

MV SWITCHGEAR UP TO 24kV

____________________________

REV – DRAFT 8 1 MARCH 2010

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BLANK PAGE

of 10





INDEX TO PEE STANDARD NUMBER 003

METAL-CLAD SWITCHGEAR UP TO 24kV

TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5 2.1 Standards 2.2 Statutory Requirements

3. VARIATIONS FROM AND ADDITIONS TO THE NRS 003 SERIES AND NRS 006 SPECIFICATIONS 6 3.1 Circuit Breaker Operating Mechanism 3.2 Small Wiring and Terminations 3.3 Power Cable Terminations 3.4 Voltage Transformer Burdens 3.5 Short-time Current Ratings 3.6 Test Prods (Probes) 3.7 Insulating Medium 3.8 Integral Earthing 3.9 Relays 3.10 SCADA

4. QUALITY 8 4.1 General 4.2 Quality Assurance Provisions

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PAGE 5. DRAWINGS 8 5.1 General 5.2 Final Copies

AMENDMENTS An Amendment Sheet, giving a record of changes / updates to this Standard, is included as the last numbered page(s).

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PEE STANDARD NUMBER 003


1. SCOPE This Standard provides for the design, manufacture, works testing, supply, delivery and off-loading of indoor distribution switchgear of the types and ratings as detailed in the particular Contract Specification. 2. REFERENCES 2.1 Standards Switchgear and any ancillary equipment supplied in terms of this Standard shall be designed, manufactured and tested in accordance with the relevant provisions of the following NRS and the Nelson Mandela Metropolitan Electrical Standards: - NRS 003-1 (Int) : 2000

- Metal-clad Switchgear – General

NRS 003-2 : 1993 (Amdt 1 – 8/96 - Metal-clad Switchgear – Std Panels

NRS 006 : 1991 - Metal – encl. Ring Main Units

NRS012(Int):1999 - Cable Terminations PEE Standard No: 100 - Protection and Auxiliary Relays

PEE Standard No: 101 - Scada Interface Requirements PEE Code of Practice 9.1 - Small Wiring Protection Design Guidelines and References – Rev 9 (As listed under PEE Codes of Practice)

2.2 Statutory Requirements All equipment offered against this Standard shall comply with the relevant requirements of the Occupational Health and Safety Act (Act 85 of 1993) as amended.

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3. VARIATIONS FROM & ADDITIONS TO THE NRS 003 SERIES AND NRS 006 SPECIFICATIONS 3.1 Circuit Breaker Operating Mechanism When the Contract Specification calls for electrical closing, the following shall apply: - 3.1.1 If closing is by means of an electrically wound spring, emergency hand-charging facilities

shall be provided. 3.1.2 Solenoid closing shall not be allowed. 3.2 Small Wiring and Terminations Small wiring and its terminations shall be done to PEE CoP 9.1 and Protection Design Guidelines and References (PDG). In case of discrepancies between the two documents, the latter (PDG) shall take preference. 3.3 Power Cable Terminations 3.3.1 All medium voltage cables to be used with the switchgear shall be of the paper-insulated lead-

armoured type. 3.3.2 Standard cable sub-types and sizes

11 kV Primary Switchgear Feeders are generally belted and unscreened 3 core cables to a maximum size of 300 mm². Cables between power transformers and its associated switchgear are normally screened single core cables to a maximum size of 630 mm². 22 kV Primary Switchgear Feeders are generally screened 3 core cables to a maximum size of 300 mm². Cables between power transformers and its associated switchgear are normally screened single core cables to a maximum size of 630 mm². 11 kV Secondary Switchgear Feeders are generally belted and unscreened 3 core cables to a maximum size of 300 mm². 22 kV Secondary Switchgear Feeders are generally screened 3 core cables to a maximum size of 300 mm².

3.3.3 Cables trenches in substations where the switchgear will be installed, shall have the following depths:

Primary switchgear : 900 mm deep; Secondary Switchgear : 600 mm deep.

3.3.4 Cable terminations shall be one of the following two types:

Air insulated termination type 1 to NRS012 (no cable glands are required, but constant spring terminals shall be provided for clamping the earth strap to the lead armour) or;

Where the normal current rating of the switchgear allows, type C or D bushings (bolted slide-on) good for RCAB or equivalent ends on 11 kV and RICS or equivalent ends on 22 kV.

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3.3.5 With all of items 3.3.1 to 3.3.4 taken into consideration, the switchgear shall allow for cable

terminations without “lifting” the gear from the substation ground level by way of platforms or similar, and without exceeding the bending radii of the cables.

3.3.6 The phase sequence shall be stamped on the outside of each cable termination compartment

(CT chamber). 3.4 Voltage Transformer Burdens All voltage transformers shall be supplied complete with a Burden Box, that is suitably and safely installed and which shall be capable of continuously loading the voltage transformer secondary at twenty five percent of the rated output. The burden shall be supplied on a separately fused and dedicated circuit. 3.5 Short-time Current Ratings The rated short-time withstand r.m.s current shall be minimum 25kA for 3 seconds in respect of both 11kV and 22kV switchgear. Higher fault ratings may be specified in the Contract Specification. 3.6 Test Prods (Probes) All switchgear shall be supplied with either separate test prods or an integral arrangement, either of which must allow both primary injection testing and cable fault location to be carried out. 3.7 Insulating Medium For 11kV isolators (switch-disconnectors) and switch-fuse combination units, only air or SF6 insulation shall be considered. Preference may be given to SF6 insulation. 3.8 Integral Earthing 3.8.1 Withdrawable Circuit Breaker Panels Both the circuit earthing and the busbar earthing shall be of the integral type where the circuit breaker is used to close the earthing circuit. Should the panel not offer this requirement for the busbar earthing, a separate free-standing panel equipped with its own circuit breaker shall be used to facilitate this requirement. In the case of single busbar circuit breaker panels, bus sections may be used to facilitate busbar earthing, provided that it is done via the main circuit breaker. 3.8.2 Non-withdrawable (fixed or modular) type circuit breaker Panels Circuit earthing shall be done via a built-in isolator / earth switch combination, where the earth switch cannot be closed prior to the opening of the isolator. Busbar earthing may be required in the form of a separate free-standing panel. 3.9 Relays Where relays are specified, these shall comply with PEE Std 100. 3.10SCADA All SCADA functionality (analogues, statuses, alarms, controls) shall be provided in accordance with PEE Standard 101, unless specifically NOT called for in the Project Specification. Where relays are

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specified as IEC61850 compliant in the Project Specification, the SCADA functionality shall be provided in IEC61850 format. 4. QUALITY 4.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen/women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 4.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 5. DRAWINGS 5.1 General

All drawings shall be to scale and fully detailed.

All important dimensions shall be given.

Drawings submitted for approval shall be in triplicate and the contractor shall supply any further copies upon request.

The original drawings shall be prepared in such a manner that they comply fully with the

requirements of SABS 0111 : Part 1 : Engineering Drawing – General Principles. 5.2 Final Copies The supplier / contractor shall provide copies of the final “as-built” drawings at the end of the contract.

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PEE STANDARD : NUMBER 003



REV NO.

DETAILS

AUTHOR


1

Added Clauses: - 3.3.1 3.3.2 3.3.3 3.3.4

MTO

11 December 1995

2

Amended Clauses: - 2.1 2.2 4.1 4.2 Deleted Clauses: - 3.3.2 3.3.3 3.3.4 These Clauses now covered in NRS 003 Series)

BCF

4 August 1998

3

Removed previous 3.1: - The relays do not have sufficient contacts to support protection functions, this alarm and the requirements of the SCADA 101 Standard. In future switchgear will be purchased equipped for SCADA. If there is no RTU at the substation and there is a pilot pair available then the trip on protection alarm will be provided by bus-wiring the contact provided for SCADA indication

MTO

5 August 1999

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REV NO.

DETAILS

AUTHOR


4

Removed 1.2 under scope Updated applicable Standards in 2.1 Removed any mention that equipment will be installed by the purchaser Added Section 3.4 – Requirement for Voltage Transformer burdens Updated Section 4.2 Under Section 3.2.1 included Entrelec Terminals as an alternative Added Section 5.2 : Requirement for “as-built” drawings

BCF

SDM

MTO

28 November 2000

5

Amended Clause 3.4 to read better

BCF SDM

15 February 2001

6

Added Clauses 3.5, 3.6 and 3.7

BCF

10 May 2001

7

PEE Code of Practice 9.1 added under clause 2 References; Changes to clauses

3.1.2 3.2 3.3 including sub-clauses 3.5 3.7

New clauses 3.8 3.9

PG

6 June 2007

8 Changes to clauses 1 2.1 – New reference listed 3.2 3.3 3.5

New clauses 3.10

PG / MB 1 March 2010

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REV – DRAFT 4 28 APRIL 2004PEE STANDARD NO: 013

UNDERGROUND CABLES UP TO 22kV FILED-F:\DATA\STANDARDS\PEE_STD\STD 013 – UNDERGROUND CABLES UP TO 22kV\Std 013.doc

NELSON MANDELA METROPOLITAN MUNICIPALITY

ELECTRICITY AND ENERGY BUSINESS UNIT

PEE STANDARD

NUMBER:013

________________

UNDERGROUND CABLES UP TO 22kV

____________________________

REV – DRAFT 4 28 APRIL 2004

of 12



BLANK PAGE

of 12







TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5 2.1 Conditions of Contract 2.2 Standards

3. DEFINITIONS 6

4. MV CABLES 6 4.1 Departures from NRS 013 4.2 Purchaser’s Specific Requirements

5. LV CABLES 6 5.1 Paper Insulated Cables 5.2 PVC Insulated Cables 5.2.1 Conductors 5.2.2 Insulation 5.2.3 Bedding Under Armour 5.2.4 Outer Sheath 5.2.5 Earth Continuity Conductor

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PAGE 5.3 XLPE Insulated Cables 5.3.1 Materials 5.3.1.1 Conductor 5.3.1.2 Insulation 5.3.1.3 Bedding 5.3.1.4 Outer Sheath 5.3.2 Multicore Cables with Concentric CNE Conductor 5.3.3 Single Core with Split Concentric Neutral and Earth Conductor 5.3.4 Stranded Aluminium Cored Concentric Earth Cable

6. PILOT CABLES 9 6.1 Purchaser’s Specific Requirements

7. CABLE DRUMS 9

8. TESTS 9

9. MATERIAL PRICE VARIATIONS 10

10. DOCUMENTATION 10 10.1 Technical Information


12. SERVICE CONDITIONS 11 12.1 Installation of Cables


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1. SCOPE This Standard sets out the Electricity and Energy Business Unit’s requirements for the manufacture, testing, supply and delivery of the following types of underground cables: -

Multicore pilot cables

Low voltage (600 / 1000 V) cables with paper, PVC and XLPE insulation for both CNE and SNE systems

Medium voltage (11 and 22kV) cables with paper insulation

2. REFERENCES 2.1 Conditions of Contract The materials covered by this specification shall be supplied in accordance with the PEE General Conditions of Contract. 2.2 Standards The electric cables shall be manufactured, tested and supplied in accordance with the specifications listed hereunder, unless otherwise specified herein: - NRS 013 - Medium Voltage Cables

NRS 011 - Pilot Cables

SABS 1507 - Electric Cables with Extruded Solid Dielectric Insulation for Fixed

Installations

SABS ISO 9000 : 2000 - Quality Management Systems

SABS 0198 - The Selection, Handling and Installation of Electric Power Cables not exceeding 33kV

BS 6480 - Impregnated Paper Insulated Cables for Electricity Supply (600/1000V)

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3. DEFINITIONS CNE - Combined Neutral and Earth – a system where the neutral conductor is

also used to provide a path for earth continuity.

Split Concentric Cable - A cable having two conductors in a single layer concentric to the central live conductor, and separated from each other by insulating material.

PECTC - Impregnated, paper insulation, lead alloy E sheath, PVC bedding, galvanised double steel tape armour and PVC serving.

4. MV CABLES MV cables shall be in accordance with NRS 013. 4.1 Departures from NRS 013 Additional conductor sizes will be required. The cable shall be mass impregnated with a non-draining compound. 4.2 Purchaser’s Specific Requirements (This is equivalent to Schedule A of NRS 013). 22kV CABLE 11kV CABLE

4.2.1 Cable operating voltage - 12,7 / 22kV 6,35 / 11 or 3,8 / 6,6kV

4.2.2 Fault level for 1 second - 20kA 20kA

4.2.3 System earth via resistor of - 6,4 ohms 3,2 or 1,9 ohms

4.2.4 Material of: -

Conductor

-

Plain annealed stranded copper wire or ¾ hard wire for aluminium conductors

Serving - PVC PVC

4.2.5 Type of Cable - Screened Belted

4.2.6 The number of cores and size and material of the conductors will be given in each individual tender.

5. LV CABLES 5.1 Paper Insulated Cables Paper insulated cables shall be of the non-draining type in accordance with BS 6480 where applicable. 5.1.1 Cable operating voltage - 600 / 1000 V

5.1.2 Type of cable - Belted

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5.1.3 Material of: - Conductor

-

Plain annealed stranded copper or ¾ hard aluminium wire

Insulation Sheath Bedding Armouring Serving

- - - - -

Paper Lead Alloy E PVC Galvanised Double Steel Tape Armoured PVC

5.2 PVC Insulated Cables PVC insulated cables shall be manufactured in accordance with SABS 1057. 5.2.1 Conductors (A) Stranded conductors shall comply with the requirements of Class 2 conductors of SABS 1411

– Part 1. They shall be of plain annealed stranded copper wire or ¾ hard aluminium wire. (B) Where called for, solid conductors shall comply with the requirements of Class 1 conductors

of SABS 1411 – Part 1. They shall be of solid aluminium. 5.2.2 Insulation Insulation shall be PVC Type D2 to SABS 1411 – Part 2. 5.2.3 Bedding Under Armour The bedding under armour shall be extruded bedding Type B to SABS 1411 – Part 2. 5.2.4 Outer Sheath The outer sheath shall be extruded PVC Type S2 to SABS 1411 – Part 2. 5.2.5 Earth Continuity Conductor When specified an earth continuity conductor shall be incorporated in the wire armour in accordance with SABS 1411 – Part 1 and Table 15 of SABS 1507. 5.3 XLPE Insulated Cables 5.3.1 Materials 5.3.1.1 Conductor Conductors shall comply with the requirements of Class 2 conductors of SABS 1411 – Part 1. They shall be of plain annealed stranded copper wire or ¾ hard aluminium wire, with sizes as specified in the individual enquiry. 5.3.1.2 Insulation Insulation shall be XLPE Type B to SABS 1411 – Part 4.

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5.3.1.3 Bedding The bedding shall be extruded bedding Type B to SABS 1411 – Part 2. 5.3.1.4 Outer Sheath The outer sheath shall be extruded PVC Type S2 to SABS 1411 – Part 2. 5.3.2 Multicore Cables with Concentric CNE Conductor The three phase conductors shall be either copper or aluminium as specified in the individual tender. The insulation colours of the phases shall be red, yellow and blue respectively. The concentric neutral and earth conductor shall be stranded copper, laid on extruded PVC bedding. If the individual strands do not effectively touch each other, an adequate size copper equalising tape shall be applied over them. Tenderers shall provide full details of their cable construction. 5.3.3 Single Core with Split Concentric Neutral and Earth Conductor The phase conductor shall be copper or aluminium as specified in the individual tender, insulated with red XLPE. The neutral conductor shall be of copper with a cross sectional area electrically equivalent to the phase conductors. The individual neutral strands shall be covered with a thin layer of black insulation. The earth continuity conductor shall be as per Table 4 of SABS 1507 : 2001. 5.3.4 Stranded Aluminium Cored Concentric Earth Cable The four conductors shall be of stranded aluminium insulated with XLPE, the colours being red, yellow, blue and black. A concentric copper earth conductor shall be laid on PVC bedding, with a maximum gap of 4mm between the copper strands. The earth conductor shall be bound with an open spiral copper equalising tape. An overall extruded PVC sheath shall be applied. The conductor areas shall be as per the table below. The cable shall be to SABS 1507 as far as possible.

Phase Conductors

mm2

Neutral Conductor

(black) mm2

Earth Conductor (Conc./SWA/ECC)

mm2

95

95

35

120

120

35

150

150

50

185

185

70

240

240

70

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6. PILOT CABLES 6.1 Purchaser’s Specific Requirements (This is equivalent to Schedule A of NRS 011). 6.1.1 Type of cable required: Number of pairs: 19 Armouring: Aluminium wire Expected induced voltage: 5 Vi 15kV 6.1.2 The length of cable required will be given in each individual tender. 6.1.3 Nominal conductor diameter: 1,13mm2 6.1.4 Conductive coating to outer sheath: required 6.1.5 Type tests: all required 7. CABLE DRUMS 7.1 Cables are to be supplied in lengths not exceeding 300m wound on separate drums. The drums

are to be within the size ranges given in the table below and they are to be used as follows: - 7.1.1 LV cables up to 16mm2, 4 core, are each to be on small drums. Other cables may be on

either small or large drums. 7.1.2 Cables too large to suit the above limitations may be supplied in shorter lengths. The

Engineer must first approve any reduction in length below 200m.

TABLE 1 – LIMITS OF CABLE DRUM SIZE

Mass and Dimensions

Small Drums

Large Drums

Maximum mass of drum with cable

2 350 kg

4 500kg

Maximum width over bolts (and cable end if this protrudes)

1,07 m

1,14 m

Maximum diameter over battens

1,55 m

2,24 m

7.2 Steel plates with a spindle hole of 90mm diameter shall be securely bolted to each drum of

diameter 1 450mm and more. 8. TESTS 8.1 The successful tenderer will be required to submit certified copies of routine inspection and test

certificates showing the following tests in accordance with the relevant standards in duplicate for approval before the cables are despatched.

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Conductor resistance at 20oC Voltage withstand Insulation resistance Tangent of dielectric loss angle (22kV cables only).

8.2 The supplier may also be required to provide samples for testing to show that the quality and all

dimensions are correct and that the cables will withstand the bending test and subsequent applied voltage test.

8.3 The test results shall comply with the guarantees stated in the tender. 9. MATERIAL PRICE VARIATIONS 9.1 In order that tenderers will all quote on the same basis, tender prices are to be based on the

market prices of copper, aluminium, lead, PVC, steel and XLPE prevailing at the date of preparation of the tender. These will be given with each individual tender.

9.2 Any invoices submitted by the successful tenderer are to show the nett purchase price per 1 000

kg of the metals. These metals are to be purchased at the first available morning market after the order is received and, if necessary, the cable prices will be adjusted to such nett market prices by utilising the variation rates that are to be quoted in the tender. An order acknowledgement is then to be submitted by return of post giving the firm price at which the order has been booked. Documentary proof must also be included to show the nett purchase price of 1 000 kg of each metal. If the order has to be submitted by the tenderer to his principals, it is to be forwarded without delay by telefax for immediate attention.

10. DOCUMENTATION 10.1 Technical Information Tenderers are required to supply technical data, drawings and a brief description of the cables offered. 11. QUALITY 11.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 11.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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12. SERVICE CONDITIONS 12.1 Installation of Cables The cables will be laid direct in the ground to a depth of up to 1m in all types of soil, including sand, shale and clay, which may be wet or dry, according to weather conditions.

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REV NO.

DETAILS

AUTHOR


0

31 October 1993

1

Textual corrections and PESTS Cable now to have PVC bedding and PVC serving (PECTC)

MB

12 March 1999

2

Minor amendments to Standards list in Section 2.2

MB

8 February 2001

3

Amended Section 5.2.1 to allow for solid conductors. Various minor corrections plus put into new document format.

MB KD

30 March 2004

4

Amended 5.2.1 (A) and (B)

MB

28 April 2004

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REV – DRAFT 5 15 FEBRUARY 2002PEE STANDARD NO: 100

PROTECTION AND AUXILIARY RELAYS FILED-F:\DATA\STANDARDS\PEE_STD\STD 100 – PROTECTION AND AUX RELAYS\Std 100.doc




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PROTECTION AND AUXILIARY RELAYS

____________________________

REV – DRAFT 5 15 FEBRUARY 2002

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BLANK PAGE

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TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. APPLICABLE STANDARDS 5

3. REQUIREMENTS FOR ALL RELAYS 5 3.1 Relay Housing and Mounting 3.2 Relay Indication and Resetting 3.3 Relay Contacts 3.4 Labelling 3.5 Test Facilities 3.6 Micro-Processor Based Relays 3.7 Protection Relay Fail 3.8 Protection Trip Alarm 3.9 Live Alteration of Relay Settings 3.10 Standard Models 3.11 Software and Interface Equipment

4. OVER-CURRENT AND EARTH FAULT RELAYS 6

5. NEUTRAL CURRENT RELAYS 7

6. TRANSFORMER DIFFERENTIAL RELAYS 7

7. HIGH IMPEDANCE REF RELAYS 7

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PAGE 8. FEEDER DIFFERENTIAL RELAYS 7

9. AUXILIARY RELAYS 8

10. SUPERVISORY CONTROL RELAYS 8

11. AUTO RECLOSE RELAYS 8

12. INTERTRIP SEND / RECEIVE RELAYS 8 12.1 Intertrip Receive Relays – 500V and 5kV 12.2 Intertrip Send Relays


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1. SCOPE This Standard provides for the manufacture, testing, supply and delivery of relays used in protection and control schemes. 2. APPLICABLE STANDARDS The relays and the materials and accessories used in their construction shall, unless otherwise specified, be manufactured and tested in accordance with the relevant requirements of the Standards listed hereunder: - SABS 1222 - Enclosures for Electrical Equipment Classification by IP Code

IEC 60255 - Electrical Relays

IEC 60068 - Environment Testing

IEC 60529 - Degrees of Protection provided by enclosures (IP Code) 3. REQUIREMENTS FOR ALL RELAYS 3.1 Relay Housing and Mounting All relays mounted on the front of the panel shall be flush-mounted and, except for relays used for control purposes, shall be housed in withdrawable rear-connected cases having inspection windows. The relay enclosures shall be protected against the ingress of dust to at least protection degree IP 50. 3.2 Relay Indication and Resetting Protection and auxiliary relays shall have suitable coloured flags or LED’s to indicate which element of the relay has operated. It shall be possible to reset the relay without opening the case. It shall not be possible to manually trip the relay without opening the case.

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3.3 Relay Contacts All relays shall be capable of making the maximum current which can occur in the circuits they control. Except where the circuit is broken by an auxiliary switch, relays shall also break the current in the circuit without deterioration of the contacts. 3.4 Labelling All relays shall be labelled to identify their function. The labels shall be fastened to the panel front by means of screws. 3.5 Test Facilities Current transformer operated relays shall incorporate facilities for secondary injection testing and trip circuit isolation. These facilities shall either form an integral part of the relay and its case or be provided by means of a separate test block and removable test plug. Tenderers shall itemise separately the prices for test plugs suitable for each type of test facility offered. 3.6 Micro-Processor Based Relays Relays of the solid state micro-processor based type shall be suitable for operation on the specified DC supply. Details of the relay standing load in the quiescent and operated condition must be provided. 3.7 Protection Relay Fail Relays having operational status monitored shall have a potential free pair of normally open contacts wired out to the terminal block for remote supervisory indication. The wire ferrule numbers shall be in accordance with PEE Standard No. 101 – SCADA Interface Requirements. 3.8 Protection Trip Alarm A potential free pair of normally open contacts wired out to the terminal block is to be provided for remote supervisory indication of protection tripping of the circuit breaker. The wire ferrule numbers shall be in accordance with PEE Standard No: 101 – SCADA Interface Requirements. 3.9 Live Alteration of Relay Settings It must be possible to modify relay settings and the relay characteristic curve while the equipment protected is in service and on load. If an interim state is entered during a setting change, the relay must remain stable during this state. It is acceptable for the interim state to be the maximum setting of the parameter being changed. For example, the removal of a plug from the bridge on an electromechanical relay sets the relay to the maximum plug setting while it is removed. 3.10 Standard Models Relays offered must be from the manufacturer’s standard range. Relays that require custom hardware or software modifications to be made to become suitable for the particular application are not acceptable. 3.11 Software and Interface Equipment Details and prices of the required software, the software licensing requirements and any special interface cables shall be provided for relays having facilities for programming settings and/or recording and retrieval of fault data by means of a lap top computer.

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4. OVER-CURRENT AND EARTH FAULT RELAYS Relays of the inverse definite minimum time lag type are to have current-time characteristics complying with IEC 60255. At least the standard inverse and extremely inverse curves are to be provided. Modification of the current-time characteristic curve is to be applied by means of a time multiplier setting, which is to have an adjustable range of at least 0,05 to 1 in steps of not greater than 0,05. Relays where settings are applied by the entering of the relay trip time at a multiple of current setting are not acceptable. Phase fault elements are to have a current setting range adjustable from at least 50% to 200%. Earth fault elements are to have a current setting range adjustable from at least 20% to 80% of the normal rated current, in at least seven steps. High set over-current relays shall be of the transient free type. The current setting range shall be adjustable from at least 400% to 2 000% in steps of 1 times the setting of the associated IDMTL relay. The relays shall incorporate a time delay adjustable up to at least 0,1 second. Sensitive earth fault relays are to have a setting range of at least 1% to 50%. The operation is to be time delayed with a setting range from 1 second to 10 seconds. The relay is to incorporate second and third harmonic rejection. When auto-reclosing of the circuit breaker is specified, a trip initiated by sensitive earth fault shall not initiate auto-reclosing. 5. NEUTRAL CURRENT RELAYS Neutral current relays are to be of the self-resetting instantaneous type with settings adjustable from 15% to 90%. The relays are to be provided with a hand-reset indicator flag. A clean pair of contacts shall be wired out to the circuit breaker multi-core terminal box to initiate a neutral alarm. The relay shall incorporate an adjustable self-resetting time with a setting range from 1 second to 8 seconds, initiated by an instantaneous earth fault element, for standby earth fault tripping. The relay shall be wired to trip all circuit breakers feeding in fault current. The relay shall be rated for at least 5 times n for 10 seconds. 6. TRANSFORMER DIFFERENTIAL RELAYS High speed relays for transformer differential protection shall be biased to provide stability on through faults. The relay shall incorporate second harmonic restraint features to prevent operation on magnetising in-rush. Offers for relays, which provide a total transformer protection and indication scheme will be considered. 7. HIGH IMPEDANCE RELAYS Restricted earth fault relays shall be of the instantaneous high impedance type with a voltage setting range of 15 – 170 V, adjustable in steps of not more than 5 V. The operating current shall not be more than 20mA. 8. FEEDER DIFFERENTIAL RELAYS Balanced feeder protection relays are to provide phase and earth fault protection. The relays at each end of the feeder are to be suitable for linking by a single pair of unscreened pilot wires with a loop resistance of up to 1 000 ohms and a maximum capacitance between cores of 2,5 micro-farad.

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In addition to the requirements of Clause 3.5, relays not having trip circuit isolation facilities as an integral part of the relay and its case shall have the trip circuits wired via removable isolation links. The relays to be supplied must, unless otherwise specified, be functionally compatible with Reyrolle Solkor ‘R’ protection. 9. AUXILIARY RELAYS Buchholz, explosion diaphragm, master trip, winding and oil temperature auxiliary relays are to have mechanically latching hand-reset contacts. When the flags drop, the contacts are to disconnect the relay coils and also close the output contacts. 10. SUPERVISORY CONTROL RELAYS Supervisory trip and close relays shall be of the self-resetting type. 11. AUTO-RECLOSE RELAYS Auto-reclose relays shall be adjustable from one to four reclosures to lock-out. The dead time is to be adjustable from 1 to 10 seconds and the reclaim time from 1 to 60 seconds. Indication of lock-out shall be by means of a flag indicator. The relay shall incorporate an anti-pumping feature and provide contacts for blocking instantaneous protection. A cumulative operation counter is to be incorporated on the relay or circuit breaker panel. 12. INTERTRIP SEND / RECEIVE RELAYS Intertrip send / receive systems shall be of the type utilising a single pilot pair. 12.1 Intertrip Receive Relays – 500 V and 5kV 500 V intertrip receive relays shall remain stable with induced pilot voltages of up to 500 V, 50 Hz across their terminals. The relay coil circuit / contacts shall be insulated for 5kV rms AC. 5kV intertrip receive relays shall remain stable with induced pilot voltages of up to 5kV, 50 Hz across their terminals. The relay coil circuit / contacts shall be insulated for 5kV rms AC. It must be possible to operate the relay by hand with the front cover removed. The relay shall be suitable for operation in conjunction with the pilot cables and nominal sending end voltage specified. The relay shall have a minimum pick-up voltage of 50% of the normal receiving end voltage. 12.2 Intertrip Send Relays Intertrip send relays are to have mechanically latching hand-reset contacts. When the flag drops, the contacts are to disconnect the relay coil and the intertrip receive relay coil, if applicable.

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REV NO.

DETAILS

AUTHOR


2

Added Section 3.7: Protection Fail Indication Added Section 3.8: Protection Tripping Contacts

MTO

28 March 1996

3

Provision for relays to be battery powered removed

MTO

1 October 1997

4

Added Clauses 3.9 and 3.10 Modified Sections 4 and 8 Changed 10 seconds to 8 seconds in Section 5

SDM MTO

22 November 1999

5

Modified Table of Contents Modified Section 2 – updated Applicable Standards Modified Clauses 3.7; 3.8; 3.10 and Added Clause 3.11 Modified Section 4

MTO

15 February 2002

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REV – 22 1 MARCH 2010PEE STANDARD NO: 101

SCADA INTERFACE REQUIREMENTS FILED-F:\DATA\STANDARDS\PEE_STD\STD 101 – SCADA INTERFACE REQUIREMENTS\Std 101.doc



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SCADA INTERFACE REQUIREMENTS

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REV – 22 1 MARCH 2010

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BLANK PAGE

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TABLE OF CONTENTS

PAGE 1. SCOPE 6

2. APPLICABLE STANDARDS 6

3. REQUIREMENTS 6 3.1 Transducers 3.1.1 Requirements for All Transducers 3.1.2 Current Transducers 3.1.3 Voltage Transducers 3.1.4 Tap Position Transducers 3.2 Status Indication 3.2.1 Circuit Breaker Status 3.2.2 Isolator Status 3.3 Control 3.3.1 General Requirements for Supervisory Control Relays 3.3.2 Supervisory Selector 3.3.3 Trip/Close 3.3.4 ARC ON/OFF 3.3.5 Sensitive Earthfault ON/OFF 3.3.6 Tap Change Control

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PAGE 3.4 Alarms 3.4.1 Supervisory Selector Switch Off 3.4.2 Closing Spring Discharged 3.4.3 MCB Off 3.4.4 Low Gas/Air Pressure 3.4.5 Neutral Current Detected 3.4.6 ARC Off 3.4.7 Sensitive Earthfault Switched Off 3.4.8 Protection Fail 3.4.9 Protection Operated 3.4.10 Transformer Fault 3.4.10.1 Type “A” Urgent Alarm 3.4.10.2 Type “B” Non-Urgent Alarm 3.4.11 VT Supply Fail 3.5 Wiring 3.5.1 Wiring Out of Circuits 3.5.2 Contacts 3.5.3 Circuit Protection 3.6 Wiring Ferrule Numbers 3.6.1 Method of Implementation 3.6.2 Current and Voltage Indication 3.6.3 Tap Changer Status 3.6.4 Circuit Breaker Status 3.6.5 Isolator Status 3.6.6 Controls 3.6.7 Alarms

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PAGE LIST OF FIGURES

FIGURE 1 SAKT2 Current Transducer Terminal Assembly 15

FIGURE 2 Drawing No. YS 000017 – Rev 2 Arrangement for Supervisory/Local Control of CB, ARC and SEF Functions

16

FIGURE 3 Drawing No. YS 000018 – Rev 0

Typical Local Indication and SCADA Alarm Arrangements

17


ANNEX(ES) ANNEX A Supervisory Functions – Ferrule Numbers

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1. SCOPE This Standard covers the requirements for the interface to the Council’s existing supervisory control and data acquisition equipment. It details the interface equipment to be provided, the wiring ferrule numbers and method of implementation, which shall be used by the manufacturer. 2. APPLICABLE STANDARDS The equipment shall, unless otherwise specified, be manufactured and tested in accordance with the relevant requirements of the latest versions of the Standards listed hereunder: - IEC 51 : Direct Acting Indicating Analogue Electrical Measuring Instruments

SABS 1222 : Enclosures for Electrical Equipment (Classification According to the Degree of

Protection that the Enclosure Provides) 3. REQUIREMENTS 3.1 Transducers 3.1.1 Requirements for All Transducers The transducer shall have an output of 0 – 20 mA DC into a loop impedance of at least 750 ohms. The basic accuracy class of the transducer shall be Class 1.0 to IEC 51. The transducer must withstand an impulse voltage of 5kV, 1,2/50 micro-second impulse in accordance with the IEC Standard. The transducer must also withstand a test voltage of 2kV, 50 Hz for one minute, between all circuits strapped together and the case earth. The transducer enclosure and the terminals must have degrees of protection of at least IP 40 and IP 20 respectively. 3.1.2 Current Transducers A current transducer is to be fitted on each panel that is equipped with over-current / earth fault protection.

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The transducer shall be connected in the yellow phase over-current CT circuit using the terminal assembly shown in the attached drawing Figure 1 – SAKT2: Current Transducer Terminal Assembly. The transducer shall be of the passive type, not requiring an auxiliary supply. The transducer shall give full output for an input current equal to the rated CT secondary current and withstand transformed over-currents up to the short-time rating of the switchgear. The input burden of the transducer at rated current shall not be greater than 1,5 VA. 3.1.3 Voltage Transducers A voltage transducer shall be fitted on each panel where the circuit has a voltage transformer. The transducer shall be connected to the yellow and blue phases of the VT circuit. The transducer shall of the active type, with auxiliary supply being derived from the VT. The nominal input of the transducer shall be 110V AC, but the transducer shall be scaled for a voltage range of 80 to 130V, with 0 mA at 80V and 20 mA at 130V. The input burden of the transducer shall be not greater than 2,5 VA. 3.1.4 Tap Position Transducers A tap position transducer shall be fitted on each tap change control panel to provide local and SCADA indication of tap position. 3.2 Status Indication Auxiliary switches shall be provided to give indication of statuses listed below. When the status is true, it shall be indicated by closure of a contact. 3.2.1 Circuit Breaker Status The status indications are to apply to circuit breakers and also to any earthing panels. Closed Open Busbar selected Feeder earth selected Busbar earth selected 3.2.2 Isolator Status Busbar isolator closed Line isolator closed Line earthing switch closed 3.3 Control 3.3.1 General Requirements for Supervisory Control Relays Interposing relays used for supervisory control purposes may be of the plug in type adequately rated for the duty to be performed

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The relays will be switched via a contact in the supervisory outstation, the power being derived from the associated panel’s DC supply. The duration of the supervisory contact closure is 1 second. Electrically set/reset relays shall be provided for control functions, which require a continuous control signal. 3.3.2 Supervisory Selector A selector switch shall be provided on all panels having supervisory control functions. Selection of the switch to the “ON” position shall inhibit local manual operation of all control functions. 3.3.3 Trip/Close Interposing relays shall be provided to trip and close the circuit breaker by supervisory control. 3.3.4 ARC ON/OFF Circuit breaker panels fitted with auto-reclose relays shall be provided with interposing relays to turn the ARC function on or off by supervisory control. Supervisory selection of ARC in or out of service shall override local manual selection of the ARC mode. The panel shall be fitted with a white LED indicator lamp to provide visual indication of ARC in service. 3.3.5 Sensitive Earthfault ON/OFF Circuit breaker panels fitted with sensitive earthfault (SEF) protection shall be equipped with interposing relays to turn SEF ‘ON’ or ‘OFF’. Supervisory control of SEF protection shall override manual ON/OFF selection of SEF. The panel shall be fitted with a white LED indicator lamp to provide visual indication of SEF in service. 3.3.6 Tap Change Control If called for in the specification, tap change control panels shall be provided with interposing relays to allow supervisory take-over of tap change control and the raising and lowering of tap position. 3.4 Alarms Relays, auxiliary switches, etc. shall be fitted to provide remote supervisory indication of the following conditions: - 3.4.1 Supervisory Selector Switch Off 3.4.2 Closing Spring Discharged Circuit breakers with motor-wound spring mechanisms are to be provided with a potential free contact, which closes when the spring is discharged. The contacts shall be connected to a common bus wire and operate a delay timer fitted within a suitable panel (a bus section or bus coupler if available). The timer shall close a pair of contacts if the spring does not charge within the designed charging time period. 3.4.3 MCB Off Each MCB or ganged set of MCB’s is to be provided with one auxiliary switch contact, which is to close when the MCB is open.

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All such contacts within a panel are to be connected in parallel. 3.4.4 Low Gas / Air Pressure Gas insulated / air pressure operated switchgear shall be provided with low pressure detection relays, which shall close a contact on loss of pressure. 3.4.5 Neutral Current Detected On panels fitted with standby earthfault, an alarm is to be initiated by operation of the instantaneous neutral current sensing relay. 3.4.6 ARC Off Panels equipped with auto-reclose relays are to provide indication if auto-reclosing is switched out of service, either manually or by means of supervisory control. 3.4.7 Sensitive Earthfault Switched Off Panels equipped with sensitive earthfault protection are to provide indication if sensitive earthfault is switched out of service, either manually or by means of supervisory control. 3.4.8 Protection Fail Indication is to be provided from relays equipped with output contacts, which monitor the state of the relay. 3.4.9 Protection Operated A potential free pair of normally open contacts wired out to the terminal block is to be provided for indication of protection tripping of the circuit breaker. Contacts are to be grouped into one of the categories given below ferruled in accordance with Section 3.6.7: - Sensitive earthfault operated Transformer protection operated Feeder protection operated Intertrip operated 3.4.10 Transformer Fault Operation of the protection or functions listed below are to close contacts in the tap change panel. Type “A” alarm contacts on each tap change panel are to be connected in parallel to give a single output. Type “B” alarm contacts are to be similarly connected. 3.4.10.1 Type “A” Urgent Alarm Buchholz main task Winding temperature Low oil Buchholz tap changer Oil temperature Pressure relief device

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3.4.10.2 Type “B” Non-Urgent Alarm Out of step Taps not complete VT supply fail Taps not commenced AC supply fail Cooler supply fail 3.4.11 VT Supply Fail When fitted, voltage monitoring relays are to close a contact on loss of normal voltage supply. 3.5 Wiring 3.5.1 Wiring Out of Circuits All transducer, status, control and alarm circuits shall be wired to a separate group of terminals that will connect the circuits to the RTU. The terminals shall be of the disconnect test type, Klippon WTR 2.5 or Entrelec M/6SN. Suitable provision is to be made for the glanding off and connection of a multicore cable to be provided by the purchaser. 3.5.2 Contacts Status indication and alarms shall be provided by means of potential free contracts. The contacts shall have a minimum rating of 30V DC, 1 A. 3.5.3 Circuit Protection Circuits shall be suitably protected so that a fault on the wiring or relays will not cause a loss of DC supply to the trip circuit of the main circuit breaker. 3.6 Wiring Ferrule Numbers 3.6.1 Method of Implementation Application of the wiring ferrule numbers for supervisory functions as given in the following clauses and incorporation of these into the circuitry shall be as set out on the latest revisions of Drawing Numbers YS 000017 and YS 000018. The supervisory functions with wiring ferrule numbers for the typical types of circuit breaker panels are set out in Annex A. No terminal allocation shall be made for functions that are not used. Where marshalling within a single cabinet necessitates duplication of ferrule numbers, the purchaser shall provide suitable suffixes.

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3.6.2 Current and Voltage Indication Current Transducer X7

X8 Voltage Transducer X11 X12 Tap Position Transducer X15 X16

3.6.3 Tap Changer Status M/F = Master / Follower principle CI = Circulating current principle B = Both

Common B X29 Follower M/F X30 Master M/F X31 Auto/Supervisory M/F X32 Local/Manual M/F X33 Local Transformer Drive Mech B X34 Supervisory Control On M/F X35 AVR Control On M/F X36 Remote Transformer Drive Mech B X37 Supervisory Selector On CI X40 Supervisory Selector Off CI X41 Manual CI X42 Auto CI X43

3.6.4 Circuit Breaker Status Closed X101

Open X102 Common X103 Top/Front Busbar Selected X104 Bottom/Back Busbar Selected X105 Feeder Earth Selected X106 Top/Front Busbar Earth Selected (Normally Earth panel only) X107 Bottom/Back Busbar Earth Selected (Normally Earth panel only) X108 ARC Out Of Service X109 SEF Out Of Service X110 Service Position (Bus coupler & single BB) X111 CB Line Earth (GIS Switchgear Only) X112 CB Busbar Earth (GIS Switchgear Only) X113 Busbar Earth Selected (Single Busbar Switchgear) X114

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3.6.5 Isolator Status Common X131

Main 1 / East Busbar X132 Busbar Isolator A for Bus Sections X134 Busbar Isolator B for Bus Sections X136 Main 2 / West Busbar X142 Reserve 1 / East Busbar X152 Reserve 2 / West Busbar X162 Line / Transformer Isolator X182 Line Earth Switch A X192 Line / Trfr Isolator CB ES X196 Busbar Isolator A CB ES X193 Busbar Isolator B CB ES X195 Transformer Earth Switch A X194

Line Earth Switch B X197 Transformer Earth Switch B X198 Reserve BB CB ES X199

Notes on using the above numbers: If only one BB is in use, use the terminology for the Main BB and not for BB Isolators A & B. For Bus Couplers on double BB arrangements, use Main & Reserve status and not Bus Section.

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3.6.6 Controls Circuit Breaker Trip W1

Circuit Breaker Close W2 Common

W3

ARC Facility Switched On W4 ARC Facility Switched Off W5 Sensitive EF Switched On W6 Sensitive EF Switched Off W7 Supervisory Control M/F W8 AVR Control M/F W9 Tap Position Raise B W10 Tap Position Lower B W11 Auto Select CI W12 Manual Select CI W13 (Main) BB Iso 1 open (Iso A in case of Bus Section) W14 (Main) BB Iso 1 close W15 (Res) BB Iso 2 open (Iso B in case of Bus Section) W16 (Res) BB Iso 2 close W17 Line / Trfr Iso open W18 Line / Trfr Iso close W19 Main BB Iso CB ES open (CB ES A in case of bus section) W20 Main BB Iso CB ES close W21 Res BB Iso CB ES open (CB ES B in case of bus section) W22 Res BB Iso CB ES close W23 Line / Trfr ES A open W24 Line / Trfr ES A close W25 Line / Trfr ES B open W26 Line / Trfr ES B close W27 Line / Trfr Iso CB ES open W28 Line / Trfr Iso CB ES close W29

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3.6.7 Alarms Bus Zone Trip X252

Bus Zone Switched Off X253 Neutral Alarm X272 General Earth Fault Operated X273 Common X281 MCB Trip X282 VT MCB Trip X283 DC Fail X285 VT Supply Fail X292 Trip Supply/Battery Fail X302 Closing Supply/Battery Fail X303 Supervisory Selector Off X312 Auto-Reclose Switched Off X332 Protection Fail X352 Protection Pilot/Fibre Fail X353 Feeder Protection Operated X362 Standby Earth Fault Operated X363 Transformer Protection Operated X365 Intertrip Operated X369 Trip Circuit Supervision X375 Closing Spring Discharged Delay Timer X382 Low Gas/Air Pressure X386 SF6 Gas Lockout X388 Cable Low Oil Pressure X392 Sensitive Earthfault Operated X464 Sensitive Earthfault Switched Off X466 Transformer Alarm Common X600 Transformer “A” Alarm X601 Transformer “B” Alarm X701

CI principle type B alarms Voltage regulating Relay Fail Parallel Operational Error High Circulating Current Taps Not complete VT supply fail AC supply fail

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FIGURE 1 – SAKT2 – CURRENT TRANSDUCER TERMINAL ASSEMBLY

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FIGURE 2 ARRANGEMENT FOR SUPERVISORY/LOCAL CONTROL OF CB, ARC & SEF FUNCTIONS

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FIGURE 3

TYPICAL LOCAL INDICATON & SCADA ALARM ARRANGEMENTS

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PEE STANDARD: NUMBER 101



REV NO.

DETAILS

AUTHOR


15

Section 3.4.9 modified Section 3.6.7 – Added X 369

GSA 13 November 2001

16 Annex A updated and modified

GSA 4 June 2002

17

Section 3.6.5 – Additions Section 3.6.7 – Additions Annex A – Addition

GSA 13 November 2002

18

Section 3.6.4 – Additions Section 3.6.7 – Additions Annex A – Additions

GSA 4 September 2004

19

Section 3.6.5 added Provisional Numbers X136 and X195

PG 11 March 2005

20

Section 3.4.10.2 – Type “B” Non-Urgent Alarms removed; Faulty Mechanism, Fire Sprinklers Operated, Taps Faulty.

PG 03 May 2005

21 Numbers added to clauses 3.6.2 to 3.6.7 PG 5 November 2009

22

ARC lamp colour changed from red to white in section 3.3.4. SEF lamp colour changed from red to white in section 3.3.5.

PG 1 March 2010

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REV – DRAFT 9 29 April 2005PEE STANDARD NO: 102 POWER TRANSFORMERS

FILED-F:\DATA\STANDARDS\PEE_STD\STD 102 – POWER TRANSFORMERS\Std 102.doc




________________

POWER TRANSFORMERS

____________________________

REV – DRAFT 9 29 April 2005

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BLANK PAGE

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POWER TRANSFORMERS

TABLE OF CONTENTS

PAGE 1. SCOPE 6

2. REFERENCES 6

3. PRICING AND PERFORMANCE PENALTIES 7 3.1 Tender Prices 3.2 Capitalisation Formula 3.3 Performance Penalties 3.4 Rejection of Transformer

4. REQUIREMENTS 8 4.1 Ratings 4.2 Core 4.3 Windings 4.4 Insulating Oil 4.5 Tank and Accessories 4.6 Oil Conservator and Accessories 4.7 Valves 4.8 Cooling Arrangements 4.9 Cable Sealing Boxes 4.10 Bushings

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PAGE 4.11 On-Load Tap-Changing Equipment 4.12 Current Transformers 4.13 Voltage Transformers 4.14 Internal Small Wiring 4.15 Secondary Wiring Terminals 4.16 Multi-core Cables 4.17 Auxiliary Supply Voltages 4.18 Neutral Earthing Conditions 4.19 Fabrication Materials, Construction, Finish, Painting and Galvanising

(Anti-Corrosion Treatment)

4.20 Transport and Erection 4.21 Labels 4.22 Gasket Material 4.23 Vibration and Noise 4.24 Spares and Special Tools 4.25 Insurance


6. DRAWINGS 35 6.1 General 6.2 Drawings to be submitted with Tender 6.3 Drawings to be submitted within three months of placing the order 6.4 Drawings to be supplied before manufacture is commenced 6.5 Maintenance Manuals

7. TESTS 36 7.1 Test Certificates 7.2 Internal Pressure and Vacuum Tests

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PAGE Tables Table 1 Power Transformer Alarm and Indication Requirements. 26 Table 2 Maximum Permanent Deflection of Steel Tank Panels. 40 Drawings

A4/451 Schematic for Supervisory Tap-Changer Interface. 41


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POWER TRANSFORMERS

1. SCOPE This Standard covers the design, manufacture, supply, testing before delivery, off-loading, erection, filling with oil and pre-commission site testing of power transformers. 2. REFERENCES The transformer shall be designed, constructed and tested in accordance with the latest editions of the PEE Standards / COP’s, SABS, IEC, British and any other standards listed hereunder, where applicable, unless otherwise specified in the Tender Contract Documents for a particular tender invitation. PEE STD 100 - Protection Relays

NRS 039 - Surge Arrestors

SABS 150 - PVC Insulated Electric Cables

SABS 555 - Insulating Oil for Transformers

SABS 679 - Zinc-Chromate Primers for Steel

SABS 763 - Hot-Dip Zinc-Coatings

SABS 0111 - Engineering Drawing

SABS 1035 - Insulated Bushings

SABS 1037 - Standard Transformer Bushings

SABS 1091 - National Colour Standards for Paint

IEC 99-4 - Metal-Oxide Arrestors without Gaps for AC systems

IEC 76 - Power Transformers

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IEC 85 - Method for Determining the Thermal Classification of Electrical Insulation

IEC 137 - Bushings for Alternating Voltages above 1 000 Volts

IEC 185 - Current Transformers

IEC 186 - Voltage Transformers

IEC 354 - Loading Guide for Oil-Immersed Transformers

IEC 551 - Measurement of Transformer and Reactor Sound Levels

BS 162 - Electric Power Switchgear

BS 223 - Bushings for Alternating Voltages above 1 000 Volts

BS 308 - Engineering Drawings Practice

BS 1872 - Specification for Electro-Plated Coatings of Tin

BS 2562 - Cable Boxes

BS 3042 - Standard Test Fingers

BS 4360 - Weldable Structural Steels

BS 4504 - Flanges and Bolting for Pipes, Valves and Fittings

BS 4571 - On-Load Tap Changers

BS 5000 - (Part 11) – Electric Motors

NB! PEE STD – DENOTES AN ELECTRICAL STANDARD ISSUED BY THE NMMM ELECTRICITY AND ENERGY BUSINESS UNIT MANAGER

3. PRICING AND PERFORMANCE PENALTIES 3.1 Tender Prices In order that tenderers will all quote on the same basis if the price is not firm, tender prices are to be based on the applicable SEIFSA contract price adjustment formula and base prices for the month prior to tender closing date. All base prices for materials and labour shall be stated, together with the adjustment formula. The price quoted is to include all delivery charges and other costs or dues that may become payable whilst the transformer is in transit from the place of manufacture to its position on a concrete plinth at the site as defined. The distance from the Port Elizabeth harbour to the substation will be given in the individual tender. 3.2 Capitalisation Formula The basic tender price of the transformer will be adjusted by the capitalised cost of the tendered losses for tender adjudication purposes. In comparing the prices of various tenders, the capitalised tender price will be calculated as follows: - C = P + A *Wfe + B *Wcu

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where: - C = capitalised cost of one transformer (Rands) P = actual tender price including installation Wfe = full load iron loss (kW) Wcu = full load copper loss (kW) A = capitalised cost per kW of iron losses (Rands/kW) B = capitalised cost per kW of copper losses (Rands/kW) Act = actual tnd = tendered A and B are based on current maximum demand and energy costs, the load factor and the net discount rate over the life of the transformer. The constants A and B will be given in the individual Tender Invitation Contract Specification. 3.3 Performance Penalties In the event of the capitalised cost based on the measured losses being greater than that based on the tendered losses the Council will impose a penalty. This will be calculated as follows: - Penalty (Rands) = A *Wfe (act) – Wfe (tnd) + B Wcu (act) – Wcu (tnd) Where the symbols are those used in the calculation of the capitalised tender price. Note that, in calculating the penalty, no allowance will be made for any tolerances permitted by IEC 76. 3.4 Rejection of Transformer In the event of the measure losses being greater than the tendered figures by an amount in excess of the tolerance allowed in IEC 76, Table III, the Council will have the right, at its sole discretion, to reject the transformer. 4. REQUIREMENTS 4.1 Ratings 4.1.1 Rated Power Where a transformer with forced air and / or forced oil cooling is offered, the naturally cooled rating of each of the main windings shall be at least 50% of the forced cooled rating of these windings. 4.1.2 Impedance Voltage The impedance voltage of the transformer shall be as defined in IEC 76, related to a reference temperature of 75oC. The zero sequence impedance, when viewed from the primary or secondary terminals, shall not exceed 20 times the primary to secondary impedance.

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4.1.3 Temperature Rise and Overloads The transformer is to be capable of giving its full rated MVA output continuously on any tapping with a maximum temperature rise of the top oil not exceeding 60oC, and a mean winding temperature rise not exceeding 65oC under the normal service conditions of IEC 76-1. Under emergency conditions, the transformer shall be capable of delivering the overload ratings recommended in IEC 354 when supplying a load having a load factor of 60%. 4.2 Core 4.2.1 Insulation The insulation between the core and the clamping structure shall withstand a test voltage of either 2kV r.m.s or 3kV DC for 60 seconds. 4.2.2 Earthing The core shall be earthed at one point only by means of a bushing with externally mounted link, which is suitably protected against damage by ladders, etc. The top and bottom core clamping structures shall be earthed to the tank, but individual core laminations and the core bolts and their individual clamping plates shall not be earthed. 4.3 Windings 4.3.1 Insulation Levels Unless otherwise specified in the particular Contract Specification, the transformer windings are to be capable of withstanding the following 1,2 / 50 micro-second impulse voltage waves when tested in accordance with the standard impulse testing procedure in accordance with IEC 76: - 550 kV for 132 kV windings 350 kV for 66 kV windings 150 kV for 22 kV windings 95 kV for 11 kV windings 75 kV for 6,6 kV windings Only 132 kV windings shall have graded insulation. All other windings are to be fully insulated. 4.3.2 Bracing of Windings The windings are to be fully pre-shrunk at the maker’s works and are to be of rigid construction amply clamped to prevent noise, movement or vibration in service. Current carrying parts of the winding connections are to be assembled either by brazing, where possible, or by the use of steel bolts. 4.3.3 Ability to Withstand Short Circuit Notwithstanding the over-current limits tabulated in IEC 76-5, the transformer shall be capable of withstanding without damage the short circuit stresses and thermal effects caused by the passage of fault currents on any terminals assuming fault levels as specified in the Contract Specification.

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4.3.4 Tertiary Winding A tertiary winding shall not be provided unless called for in the Contract Specification. 4.4 Insulating Oil 4.4.1 Quality Sufficient insulating oil complying with SABS 555 shall be supplied for the first filling of the transformer. 4.4.2 Filling The transformer shall be filled under vacuum. All oil shall be tested on site to show compliance with SABS 555. 4.4.3 PCB Content For all transformers the oil sample drawn from any part of the transformer at the time of handing over of the transformer shall not contain any detectable PCB’s. Formal certification to this effect is required and shall be included in the manual. 4.5 Tank and Accessories 4.5.1 Tank 4.5.1.1 General Unless otherwise approved, structural steel plate and sections shall comply with BS 4360. The construction of the tank shall make provision for all specified accessories including accommodation of the CT’s specified hereunder for control of the OLTC gear and for operation of protection circuits under separate contract. 4.5.1.2 Strength and Oil-Tightness The tank of each transformer shall be complete with all accessories and shall have adequate mechanical strength and rigidity to allow the complete transformer, filled with oil, to be lifted by crane or jacks, transported by road, rail or water without over-straining joints and without causing subsequent leakage of oil. The tank shall withstand the tests specified in Clause 7.2. The tank shall be constructed of continuously welded steel plate, and the bottom shall have a minimum thickness of 12,5mm. Tank stiffeners continuously welded to the tank are to be provided. Stiffeners shall not cover welded seams. 4.5.1.3 Underbase The base of the tank shall be provided with a flat base-plate under-frame of sufficient strength so that it shall be possible to move the complete transformer in any direction without injury when using rollers, plates or rails. 4.5.1.4 Shape The shape of the tank and fittings shall be such that there are no pockets outside where water can collect and internally the design shall eliminate pockets where gas can collect. Any such internal pockets that are unavoidable shall be provided with: -

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(a) Vent pipes to exhaust gas emanating from the windings to a gas and oil-activated type relay

(Buchholz Relay).

(b) Air Release Plugs (see 4.5.4). 4.5.2 Lifting and Haulage Facilities The tank shall be provided with the following: - 4.5.2.1 Lifting Lugs Four symmetrically placed lifting lugs suitable for lifting the transformer complete with oil without structural damage to any part of the transformer. 4.5.2.2 Jacking Pads Not less than four jacking pads arranged at a minimum height of 400mm above the base or as agreed to in writing with the Purchaser. 4.5.2.3 Hauling Lugs Horizontal hauling lugs with 50mm diameter draw holes shall be placed near the four corners of the tank (excluding the rounded portion of any tank). At least 150mm working space shall be allowed above and below each draw hole. The draw holes are to be placed so that the tank may be hauled or slewed in any direction. 4.5.3 Tank Cover 4.5.3.1 Construction The main tank cover shall be domed or sloping to permit free venting of gas through the Buchholz relay to the conservator. The cover shall be of adequate strength and shall not distort when the tank complete with the transformer and oil is lifted. 4.5.3.2 Access Openings and Covers Inspection openings shall be provided where necessary to give easy access to the under-oil portion of the bushings and internal current transformer connections. An inspection cover must be provided for access to the internal earthing connections of the core-earthing bushing. Each inspection opening shall be of approved ample size for its purpose. Lifting eyes shall be provided for each inspection cover and for the main tank cover. 4.5.3.3 Thermometer Pockets Thermometer pockets shall be provided in the tank cover for the bulbs of the temperature indicators specified in Clause 4.8.6. An additional thermometer pocket shall also be provided for checking purposes. The pockets are to be placed to suit the requirements of the respective instruments and shall be provided with captive caps to prevent ingress of moisture. It shall be possible to remove the bulbs or thermostat without lowering the oil level in the tank. 4.5.4 Air-Release Plugs

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Flanged type air-release plugs are to be provided where necessary to ensure rapid filling of the transformer. 4.5.5 Explosion Vent An explosion vent of the spring-loaded pressure relief type shall be mounted in the most effective position directly on the side wall of the tank. The device must be provided with at least one pair of electrical contacts, which close as the device operates and a manual reset mechanical indicator visible from ground level. The device shall be capable of preventing rupture of the tank under internal fault conditions. 4.5.6 Earthing of Main Tank Two earthing terminals capable of carrying 20 kA for one second shall be fitted diametrically opposite on the HV and LV side of the tank near any of the corners of the under-base. 4.5.7 Marshalling Kiosk The marshalling kiosk shall be of sufficient size to allow easy access for termination of multi-core cables and testing of equipment. Access to the instruments and terminal blocks shall be by means of a hinged door or slip-on cover incorporating an adequate weatherproofing seal. 4.6 Oil Conservator and Accessories 4.6.1 Construction The structural requirements of the tank, where relevant, apply equally to the conservator provided for the transformer. The conservator shall be designed, constructed and tested to comply with Clause 7.2. 4.6.2 Arrangement A single conservator having two separate oil and gas-tight compartments shall be provided to maintain the oil level in the tank and the tap change compartment respectively. Each section of the conservator shall have its own separate dehydrating breather, oil level indicator and gas and oil-operated relay. Both ends of the conservator shall be removable for cleaning purposes. A sump shall be formed by extending the main feed-pipe from the tank into the tank oil conservator, the extension of which shall be not less than 75mm. The cold oil level at –5oC shall not be less than 13mm above the top of this extension pipe. The main feed-pipe shall be brought out from the highest point on the tank cover. This pipe shall rise toward the oil conservator through the gas and oil operated relay. All gas-venting pipes shall be connected into this pipe between the transformer and the gas relay. 4.6.3 Mounting The conservator shall be mounted on the transformer tank independently from the tank cover and its bolts. 4.6.4 Capacity

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The capacity of each compartment of the conservator shall be such that when the transformer is in service with all radiators and / or coolers in use, the oil level shall be visible over the range from the maximum temperature when the transformer is hot to the minimum cold temperature. 4.6.5 Accessories 4.6.5.1 Drain Valve on Tap Change Conservator A 25mm diameter drain valve with plug shall be fitted to the tap change conservator and arranged so that when opened, the conservator will be completely drained. This valve shall be mounted on an extension pipe 1,5m above ground level. 4.6.5.2 Drain Valve on Tank Conservator A 50mm double-flanged valve shall be provided to fully drain the tank conservator. This valve shall be mounted on an extension pipe 1,5m above ground level. 4.6.5.3 Filler Plugs Flanged type filling apertures fitted with an air-tight gasket cover shall be provided on both conservators. 4.6.5.4 Oil Gauges The conservators shall be fitted with dial type oil gauges, which shall be of the magnetically operated type in which breaking of the glass will not release any oil. The oil gauges shall incorporate a set of contacts for the initiation of the alarms called for in Clause 4.11.6. 4.6.5.5 Gas and Oil-Operated Relays Two gas and oil-operated actuated type relays of ample capacity to meet the requirements shall be mounted in accordance with the maker’s recommendations, in the main feed-pipeline from tank to the tank conservator and from the tap change compartment to the tap change conservator respectively. The pipes are to be set out at the correct angle and of sufficient length to ensure correct operation of the “gas” and “surge” contacts. Sampling pipes not less than 5mm ID shall be provided and connected to gas release cocks mounted approximately 1,2m above ground level. The wiring to the trip and alarm contacts is to be brought out to a multi-core cable box for the operating of a relay supplied under separate contract that will be mounted on the remote control panel of the LV switchboard. 4.6.5.6 Isolating Valves Isolating valves of adequate size are to be provided between the conservators and their respective gas and oil-actuated relays. 4.6.5.7 Dehydrating Breathers Large capacity silica-gel dehydrating breathers of the type with an oil seal to prevent contact with the outside air except when the transformer is breathing, are to be mounted approximately 1,2m above ground level. The breathers are to have windows through which the condition of the tinted silica-gel crystals are visible.

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4.7 Valves 4.7.1 General All valves shall be of non-corrodible metal. The valves are to be of the full-way type with internal screw and shall open when turned counter-clockwise facing the hand-wheel. Every valve shall have an indicator to show the position of the valve clearly and also shall have a means of locking the handle securely in the desired position. All valves shall be attached by bolted on flanges and shall not be welded to the tank. All valves left exposed during transit shall be fitted with blanking plates. 4.7.2 Filtering and Other Valves The following valves shall be provided: - 4.7.2.1 Drain valves of adequate size arranged to ensure that the main tank and tap changer can be

drained as far as is practicable. The drain valve on the main tank shall be positioned diagonally opposite to the filtering valve.

4.7.2.2 Filtering and sampling valves mounted at the top and bottom of the tank respectively at

opposite ends. Each valve is to be provided with a blanking plate having a screwed plug for sampling purposes.

4.7.2.3 Valves for the conservators to comply with Clause 4.6.5. 4.7.2.4 Valves for the cooling apparatus to comply with Clause 4.8.2. 4.8 Cooling Arrangements 4.8.1 Constructional Details The structural requirements of the tank, where relevant, including materials, mechanical and vacuum strength, etc. apply equally to the cooling apparatus provided for the transformer. Radiators and coolers shall be designed and constructed so that all painted surfaces can be thoroughly cleaned by hand and subsequently painted in site by special brushes or sprays. Radiators and coolers shall be so designed and constructed as to avoid pockets in which moisture can collect and shall withstand the pressure test specified in Clause 7.2. The radiators and coolers shall be finished to comply with Clause 4.19. The cooling surfaces shall be made of a suitable metal and shall be either seamless tubes or of dished construction that avoids the use of a continuous spot-welding process, which leaves the edges, unfused. The cooling provided by radiator banks shall be such that the failure of one bank of radiators shall not reduce the total cooling capacity by more than 50%. The radiators and associated pipe work shall be arranged to permit free access to oil conservators, tap changer and any other items requiring inspection or maintenance in service. 4.8.2 Detachable Radiators

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Radiators connected directly to the tank shall be detachable and adequate arrangements should be made for all joints to be oil-tight. Brass flanged plugs of not less than 25mm diameter in size shall be provided at the top and bottom of each radiator for filling and draining respectively. Alternatively, tapered plugs may be provided. Detachable radiators shall be provided with lifting lugs. It shall be possible to remove a single radiator without disturbing adjacent radiators. Flanged and bolted isolating valves shall be provided on the tank at each point of connection to the radiator. 4.8.3 Oil Piping and Flanges All oil piping shall be provided to connect the radiators and the tank. The piping shall be of approved material with machined flanged joints complying with BS 4504. Cast-iron shall not be used. Blanking plates are to be provided and fitted on all flanges that would be open during transit to site. 4.8.4 Separately Mounted Cooler-Banks The use of separately mounted cooler-banks, their arrangement and pipe work, shall be to the approval of the City Electrical Engineer. 4.8.5 Forced Cooling 4.8.5.1 Control Forced cooling equipment shall be designed for automatic operation by means of winding temperature thermometer contacts set at pre-determined temperatures recommended by the contractor. 4.8.5.2 Cooler Control Equipment All the necessary automatic control, isolating switches, motor contactors, protective devices and switches for the forced cooling equipment shall be assembled in the marshalling kiosk. 4.8.5.3 Fans All fans shall be provided with hot-dip galvanised wire-mesh guards complying with the requirements of BS 3042, Test Fingers 11 and 111. Fan blades and ducting shall be of aluminium alloy and shall be designed to keep noise and vibration to a minimum. (Refer to Clause 7.1.2). 4.8.5.4 Fan Motors Fan motors shall be of the totally enclosed weatherproof type suitable for direct-on-line starting and continuous running from the supply voltage specified in the tender enquiry. All motors shall comply with BS 5000, Part 11 or Part 99, as applicable. Each motor shall be equipped with a terminal box to accommodate the incoming cable from the marshalling kiosk. Motors shall be provided with starters, overload protection and, in the case of three phase motors, single phasing protection.

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4.8.6 Temperature Indicators and Controls 4.8.6.1 General The alarm contacts on the temperature indicators shall be adjustable to close between 50oC and 100oC and to re-open when the temperature has fallen by any desired amount between 15oC and 30oC. All contacts shall be adjustable to a scale and shall be accessible on removal of the cover. Alarm and trip circuit contacts shall be suitable for making or breaking 150 VA between the limits of 30 Volts and 230 Volts AC or DC. The working parts of the instruments shall be visible by the provision of cut-away dials and glass-fronted covers, and provision shall be made for moving the pointers by hand to check the operation of the equipment. The capillary tubing must be protected by a flexible stainless steel armouring and PVC sleeve to the Purchaser’s requirements. Protection from physical damage between the kiosk and the pockets must also be provided. The instruments shall be provided with anti-vibration mountings unless mounted in a separate free-standing kiosk. 4.8.6.2 Oil Temperature Indicator One dial type thermometer of approved type, which shall operate from a bulb placed in the pocket specified in Clause 4.5.3.3 to register the “top oil” temperature. The indicator shall be fitted with adjustable alarm and trip contacts, which shall be of the mercury switch type and which can be set to close at a pre-determined temperature. 4.8.6.3 Winding Temperature Indicator The winding temperature indicator shall be of the dial type, compensated for changes in ambient temperature and shall have a load temperature characteristic approximately the same as the hottest part of the windings. The current transformer for operating this indicator shall be built into the transformer tank. (Refer to Clauses 4.12 and 7.13). The winding temperature indicator shall be supplied with adjustable alarm, trip and cooler control contacts. 4.9 Cable Sealing Boxes 4.9.1 General When cable sealing boxes are called for in the Contract Specification, the Purchaser will provide underground cables for connecting to the terminals of the transformer. The tenderer will therefore satisfy himself that the cable sealing boxes offered will be suitable for the size and type of cable stated in the Contract Specification. The cable sealing box is to be supplied complete with bushings, lugs and glands suitable for connecting the abovementioned cables to the terminals of the transformer. For connecting the cables to the LV and HV bushing terminals, flexible connectors must be provided to allow for expansion of the cable conductors. Cable boxes shall be suitable for terminating cable approaching vertically from below. 4.9.2 Cable Sealing Boxes up to 22 kV

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Cable sealing boxes are to be of heavy construction complying with BS 2562, Parts 1 and 2 and shall be mounted on the side of the transformer. The cable boxes shall be suitable for filling with a semi-fluid grade of compound. Fill and drain plugs are to be provided. The filler plug is to conform with Figure 12 of BS 2562, Part 2, except that it is to be mounted on a domed or sloping surface, which will not collect water. Each cable box is to have a loose bottom plate carrying the cable gland so that the cable does not have to be threaded through the gland while it is attached to the box. Tapered brass plumbing glands are to be insulated lightly from the gland-plate. Gland-plates must be made of material that will not heat up when full load current is passed through the cable continuously. Cable sealing boxes are to be extended to give an expansion chamber of 8% of the cable box volume. The expansion chamber is to be mounted directly above each cable box. The level of compound shall be such that all gaskets will be covered by a head of compound at least 150mm high. The cable boxes must be supplied with a detachable cover for access and cleaning purposes. Each cable box shall be fitted with a vent pipe to avoid any differential pressure in the box. A silica gel breather shall be provided to prevent moisture being introduced into the cable box through the vent pipe. 4.9.3 Cable Sealing Boxes 66 kV and above The cable boxes shall be suitable for filling with transformer oil supplied from the conservator through an isolating valve. The box must be provided with a drain plug. The cable sealing box shall be suitable for accommodating the high voltage cable sealing ends and suitable cover-plates shall be provided for inspection purposes. 4.9.4 Mounting The HV and LV cable sealing boxes, where specified, shall be symmetrically mounted on opposite sides of the transformer major axis. Supports and clamps, at intervals of not more than 1m on the side of the transformer, must be provided for rigidly supporting the LV and HV cables between the cable boxes and ground. 4.9.5 Disconnecting Chambers For all windings of 6,6 kV and above, disconnecting chambers shall be provided between each box and the transformer tank for isolating the cable from the transformer windings when necessary. Cover-plates are to be provided to give easy access to under-oil removable links. The oil in the disconnecting chamber shall be sealed from the main tank oil and the cable box compound. The box shall be connected via an isolating valve to the main feed pipe between the tank and the tank conservator. A drain valve shall be provided at the lowest point to drain the oil in the disconnecting chamber. Porcelain bushings are to be provided for the connections in the oil-immersed disconnecting chamber and each bushing is to be of the type with an oil-tight stem and a clamping flange, preferably arranged for tightening from the inside of the disconnecting chamber.

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4.10 Bushings 4.10.1 Outdoor Bushings When outdoor bushings are called for in the Contract Specification, they are to comply with SABS 1035 for extremely polluted atmospheres, and are to be porcelain shedded bushings of the bolted/clamped flange type. It shall be possible to tighten the bushing from the outside of the tank and a hand-hole cover-plate (refer to Clause 4.5.3.2) shall be conveniently positioned for easy access to the internal part of the bushing and internal connection. Bushings rated at 66 kV and above are to be of the oil-filled condenser type with oil-tight sight glass clearly visible from ground level. 4.10.1.1 Terminals Unless otherwise specified, air-side bushing terminals shall be solid copper or copper alloy. They shall be electrotinned to BS 1872, Classification Cu/z/Sn/10/b without subsequent heat treatment or machining. The terminals shall be either 26mm diameter or 38mm diameter to suit the rated current. The length shall be 125mm.

(a) Rated Current

Bushing conductors shall be capable of carrying the design current without the temperature rise of the hottest spot of the conductor or central tube of the bushing exceeding the temperature rise limits specified in IEC 137.

(b) Rated Short-Time Current

Bushing conductors shall be capable of carrying, for 3 seconds, the short-circuit currents resulting from faults related to the fault levels stipulated in the Contract Specification.

4.10.1.2 Bushing Types

(a) Outdoor Immersed Bushings

Unless otherwise called for in the Contract Specification, all open bushings shall be outdoor immersed bushings.

(b) Completely Immersed Bushings

Connections from winding leads into cable boxes or oil filled disconnecting chambers shall be effected by means of completely immersed bushings.

(c) Capacitance Graded Bushings

For all applications where system nominal voltages of 66 kV and above apply, only capacitance graded bushings shall be supplied.

(d) Tertiary Bushings

For autotransformers with tertiary windings, the low voltage (tertiary) bushings shall have a minimum insulation level corresponding to a nominal system voltage of 33 kV.

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(e) Liquid Filled Bushings

Liquid filled capacitance graded bushings shall be provided with liquid level gauges, preferably of the direct-reading prismatic type or the magnetic type. Other types of liquid level gauges will only be accepted if specifically approved.

(f) Non-fluid Filled Bushings

Non-fluid filled capacitance graded bushings will not be accepted unless specifically approved.

4.10.1.3 Test Tappings Test tappings of approved design and materials shall be provided on all capacitance graded bushings. 4.10.1.4 Screw Plugs on Bushings Filling screw plugs on bushings shall be located below the oil level so that any leak will be visible as an oil leak. Plugs shall be of a type requiring special tools for opening, filling and pressurising of the bushing. (The position of the filling screw plug will show if the plug is sealing properly). 4.10.1.5 Surge Arresters Outdoor bushings are to be supplied complete with Metal-Oxide Gapless Surge Arresters. The arresters are to be fitted to the transformer tank as close as possible to the bushings. Arresters shall be fitted to both the HV and LV and, where appropriate, to tertiary winding bushings. The connections between bushings and arresters shall be included. The arresters shall be of the 10KA Substation Class Classification – Table 1 of NRS 039. The surge arresters shall, unless otherwise specified, be manufactured and tested in accordance with, and comply in all respects with the relevant requirements of SABS IEC 99-4; Part 4. Only arresters having an external housing manufactured from a Silicone Polymer or Porcelain will be acceptable. EPDM or Cycloaliphatic materials will not be considered. (Experience shows that these insulating materials do not stand up to the severe corrosive atmospheric conditions prevailing in Port Elizabeth). 4.10.2 Insulation Levels and Creepage Distances The minimum dry lightning impulse withstand voltages and the power frequency withstand voltages applicable to the transformer windings shall also apply to the bushings. (Refer to Clause 4.3.1). Unless otherwise approved in writing, the bushings are to have a creepage distance of not less than 25mm/kV of system highest voltage. 4.10.3 Neutral Bushings 4.10.3.1 LV Side The neutral end of the LV winding shall be brought out to a shedded porcelain bushing of approved type with the same voltage rating as the transformer LV windings, and creepage distance as that specified above for LV phase bushings. Neutral bushings with lower voltage ratings will only be considered on transformers with graded insulation.

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4.10.3.2 HV Side When the neutral point on the higher voltage side is brought out to a bushing, the latter shall have the same voltage rating as the transformer HV windings and creepage distance as that specified above. Neutral bushings with lower voltage ratings will only be considered on windings with graded insulation. If a neutral bushing is not called for in the Contract Specification, the neutral point of the HV windings should be brought out to an under-oil terminal, which is accessible via a bolted on inspection blanking plate. (This will provide a test point if ever needed). 4.10.4 Alternative Bushings Alternative bushings with lower characteristics will not be considered. 4.10.5 Electrical Clearances Electrical clearances for open bushings shall be in accordance with BS 162, Tables 8 and 10. 4.11 On-Load Tap-Changing Equipment 4.11.1 General 4.11.1.1 Type On-load tap-changing equipment complying with BS 4571 shall be provided for the windings and range of tappings as called for in the Contract Specification. Each transformer is to be supplied with fully automatic on-load high speed resistance type tap-changing equipment arranged for local control and for remote electrical operation with automatic control by relays in the substation control room. 4.11.1.2 Insulation Tap-changing equipment shall be capable of withstanding the impulse and dielectric tests of the associated windings. 4.11.1.3 Rating Tap-changing equipment shall be capable of carrying the same load currents and currents due to external short circuits as the transformer windings. 4.11.2 Switch Compartment (Design of the Tap Changer) All tap-changers must be easily accessible for internal maintenance and repair. It must be possible to inspect and service the tap-change diverter switches without opening the main transformer tank or having to drain oil from the latter. The tap-change motors must have sufficient inertia to ensure completion of any tap-change operation in the event of failure of the auxiliary power supply at any time after the sequence is initiated. In addition, the diverter switches shall be operated on a toggle principle to ensure rapid changeover. The tap-change equipment shall be so designed that it will not be possible for the main transformer winding to be open circuited or for a portion thereof to be short-circuited, except through a transition impedance.

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(a) Diverter Switches and Selector Switches

The current breaking contacts of diverter and selector switches shall be easily replaceable.

(b) Diverter Switch and Selector Switch Compartments

Drop-down tanks, which necessitate the provision of pits in the foundations, are unacceptable. Each diverter and selector switch compartment shall be provided with an oil drain valve or plug. Care shall be taken, if applicable, to close all valves or plugs, which are fitted to any interconnecting pipe work between the transformer main tank and the tap changer diverter switch compartment, prior to operating the tap changers on load in the factory or after installation. Failure to do so will require full reprocessing of the oil in the transformer. Current breaking switches (e.g. diverter and selector switches as distinct from tap selectors and changeover selectors) shall not operate in the insulating oil of the main transformer. The insulating oil for these switches shall be completely segregated in a separate oil and gas-tight compartment from that in the main transformer tank. The oil conservator for maintaining the oil level in the compartments containing such switches shall be separated from the main transformer oil conservator. Where a common conservator tank construction is employed to serve both the main tank and the tap changer switching compartment, the two bodies of oil shall be segregated by an oil and gas tight steel partition. Each body shall have its own separate dehydrating breather and oil level indicator, which shall be clearly labelled to relate it to the corresponding oil body.

(c) Protective Devices for Diverter Switch and Selector Switch Compartments

Except in the case of those compartments, which are bushing mounted and operate at line or tapping potential, the protective functions to be provided for diverter switch and selector switch compartments shall effect tripping of the circuit breakers controlling the transformer in the case of: -

1. low-oil level (may be omitted if a surge relay, which fulfils this function is provided); 2. a surge of oil produced by a fault inside the compartment, or a rise in pressure or

temperature resulting from such a fault; whichever one of these three is most appropriate to the design of the apparatus.

Where a pressure sensitive device is provided, its contact shall close under steady increase of pressure, at a value not less than 100 kPa, or as recommended by the manufacturer, taking the head of oil into consideration. In addition to the above, the oil in such compartments shall only communicate with the atmosphere via a dehydrating breather containing a silica gel charge of at least 2 kg.

(d) Tap Selector and Changeover Selector Oil-filled Compartments

Where tap selectors and changeover selectors are contained in compartments separate from current breaking switches, these compartments shall be covered by the protection afforded by the Buchholz relay serving the main transformer tank, unless separate oil surge and low-oil level relays are provided. Provision shall be made for filtering and draining the oil in such compartments.

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(e) Alarm and Tripping Contacts for Protective Devices

The alarm and tripping contacts shall, comply with the requirements of PEE Standard Number 100: Protection Relays.

(f) Strength of Tap Changer Compartments and Insulating Barriers

Tap changer compartments and insulating barriers shall have adequate strength to resist the forces resulting from the application of a full internal vacuum at sea level without suffering significant permanent distortion or damage of any sort. In the case of insulating barriers, the vacuum is unequalised (i.e. applied from one side only, against atmospheric and oil pressure on the other side), and applied internally from either side, with the following provisions: - 1. In the case of tap changers energised at voltages below 66 kV, the vacuum requirements

applicable to the tap changer compartment will be limited to that which produces a pressure differential between the tap changer compartment and the atmosphere of not more than 65 kPa.

2. Where such insulating barriers serve tap changers mounted wholly within the transformer

tank, (e.g. diverter switch cylinder) the application of a vacuum or pressure may be equalised on both sides of a diverter switch compartment by interconnecting the two conservators.

(g) Sealing of Tap Changer Parts for Transport

Where it is necessary to remove parts or the whole of the on-load tap changer for transport purposes, it shall be possible to complete erection on site with the transformer windings covered with oil.

4.11.3 Driving Mechanism 4.11.3.1 Enclosure The driving mechanism shall be enclosed in a waterproof cubicle and shall be so arranged that it will not be possible for insulating oil to leak into compartments containing the electrical driving apparatus. All oil seals shall be effective and easily renewable and the design shall prevent dust or dirt entering the mechanism. 4.11.3.2 Local Electrical Control and Indicating Equipment The local control panel shall be equipped with the following facilities: - (a) Limit switches or other approved devices are to be included to prevent the mechanism over-

running under any condition;

(b) Raise / lower voltage control switch or push-buttons;

(c) Local / remote control change-over switch;

(d) A mechanical tap position indicator is to be provided and arranged to indicate the tap number in circuit through an inspection window in the case. This indicator is to be linked with the device, which operates the out-of-step control circuits and a remote electrical tap position indicator. The smallest tap number shall correspond with the highest number of HV turns (i.e. the plus percent position), and the largest tap number, the smallest number of HV turns (i.e. the minus percent position);

(e) The motor of each driving mechanism shall comply with BS 5000, Part 11 or 99 as applicable,

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and is to be suitably protected against over-heating, burning out, over-current, and in the case of three phase motors, single phasing;

(f) A cyclometer counter easily visible through an inspection window is to be included to count the number of tap change positions;

(g) Thermostatically-controlled metal-clad heaters shall be provided to prevent condensation in the mechanism boxes;

(h) A permanently legible lubrication chart shall be fitted within the driving mechanism chamber;

(i) All wiring and cabling shall comply with Clauses 4.14, 4.15, 4.16 and 4.17. 4.11.3.3 Manual Operation A hand-operated device is to be provided with the transformer to enable a tap-change to be made by hand when desired. The device shall be interlocked to prevent simultaneous electrical operation. 4.11.4 Tap-Change Remote Control Panel 4.11.4.1 Construction Each transformer shall be provided with a tap-change remote control panel of the indoor type for manual and auto control of the tap-changer from the substation building. The panel is to be of the sheet-steel fully-enclosed type, finished as specified in Clause 4.19. Hinged rear access doors with locking handles are to be provided on the panel. A 230 volt cubicle illuminating light controlled by a rear door switch is to be included together with all labels, wiring, terminal blocks and cable entries as specified herein. All relays and instruments shall be flush-mounted on the panel. 4.11.4.2 Remote Electrical Operation and Control Functions The transformer and associated equipment shall be capable of the following functions and the remote control panel shall be equipped with the following facilities: - (a) Raise / lower voltage control switch or push-buttons;

(b) Automatic control by means of a voltage regulating relay;

(c) Control switch for either auto / supervisory operation or manual operation;

(d) Control switch for Master / Follower / Solo control if the Master / Follower concept is used;

(e) The following indicating lamps shall be provided:

Tap-changer “Supply Failure” lamp; “Tap-change in Progress” lamp; A “local” lamp indicating “local” selection in the outdoor transformer driving mechanism; A “Supervisory Control On” lamp energised from the supervisory take-over relay;

(f) A supervisory take-over relay (see clause 4.11.5, bullet 3). The relay must also accommodate

hand (manual) change over from auto (re-set) to supervisory (set) selection;

(g) Tap position remote indicator; (h) Line drop compensation controls;

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(i) Multi-element indicator relay (refer to Clause 4.11.6);

(j) Three phase, 10 kA, miniature circuit breakers for the overall protection of the complete control unit. These MCB’s are to include one normally closed contact that shall be wired to “make” the alarm circuits in the substation when any of the MCB’s have been tripped;

(k) Supervisory “raise / lower” auxiliary relays.

4.11.4.3 Parallel Operation When called for in the Contract Specification, the transformer is to operate in parallel with existing transformers at the substation site. Parallel operation shall be controlled by the master / follower method. Where transformers are required to operate in parallel, the tap-change scheme shall include the following functions: - (a) A tap-change once initiated, shall be completed automatically and the circuits shall not reset to

permit the signalling of a further tap-change until the mechanism has completed its operating cycle.

(b) Out-of-step relays shall be fitted to ensure that when the transformers are in parallel, no tap-changer can operate automatically to permit any transformer becoming more than one tap out of step.

(c) Immediately a failure occurs in the coupling system, an alarm circuit shall be made and further tap-changes on any unit shall be prevented. This alarm circuit is to incorporate a delay of five minutes to ensure that the alarm signal is not sent during normal operation, and must operate the “out-of-step” alarm indicator and provide terminals for further extension of the alarm circuit by the Purchaser.

(d) A timing relay shall be provided and wired to the voltage regulating relay in such a manner that the relay will operate an alarm at 30 minutes after the regulating relay contacts make in order to cover the condition where the master tap-changer fails to respond to the voltage regulating relay. This timing relay shall also be initiated immediately when “raise” or “lower” signals are sent form the master to the follower (or from one follower to another) in order to cover the condition where the follower to which the signal is sent fails to respond to the signal.

(e) The time delay relay must operate the “Tap-Change not Commenced” alarm indicator and the Purchaser must provide terminals for further extension of this alarm circuit.

4.11.5 Remote Supervisory Control Each transformer tap-change control panel shall be fitted with facilities for interfacing with the department’s supervisory control system for remote control and indication of alarms and status. The following facilities shall be provided with the interface as shown on Diagram No A4/451 included as Page 41: -

A selector switch in the remote tap change control panel for selection between manual and auto / supervisory control;

Supervisory indication of manual selection (X29, X33) or auto / supervisory selection (X29,

X32) of the above switch;

Supervisory selection of either auto (voltage regulating relay) control (W3, W9 in accordance with PEE Std 101) or supervisory operation (W3, W8). Supervisory operation shall override auto tap-change control selection;

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Supervisory indication of the status of the above selection, (X29, X35) for supervisory control on and (X29, X36) for auto control on.

Supervisory raising (W3, W10) and lowering (W3, W10) of transformer taps. If the Master /

Follower concept is used, operation of the master tap-changer by supervisory when the follower is on local control must cause the follower to change in sympathy;

Supervisory indication of the tap position of each transformer (X15, X16);

Supervisory indication of remote (X29, X37) / local (X29, X34) selection in the outdoor

transformer driving mechanism;

If the Master / Follower concept is used, supervisory indication of whether the tap-changer is master (X29, X31) or follower (X29, X30);

The interface with the supervisory control system will be as follows: -

The SCADA controls for

Supervisory Control selection

Auto control selection

Tap Position Raise and

Tap Position Lower

Shall be provided from the RTU panel as voltage free contacts suitable for 110V DC, 1A, and giving a 100 m.s. closing time;

Status indication must be by a single pole voltage free contact in the tap-change panel all commoned to a single wire (X29).

Tap position indication must be by means of an isolated 0 – 20 mA nominal output transducer

with 1mA corresponding to the numerically lowest tap. There shall be a linear change of current with tap number.

4.11.6 Alarms Table 1 below lists all substation building alarms, substation building trip indications and SCADA alarms required for power transformers. Note that some of the alarms should come from the Relay Panel whilst others should come from the Tap Change Control Panel.

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* - Table 1 is continued overleaf. To facilitate reading follow the column numbers. (i.e. Columns 1 to 9 on Page 26 and columns 10 to 19 on Page 27).

TABLE 1 * – POWER TRANSFORMER ALARM AND INDICATION REQUIREMENTS

What?

One or two

stage element?

Does this function effect a

trip?

Should the alarm contacts be self re-setting or locking out?

Substation Alarms

1 2 3 4 5 6 7 8 9

Required? How? Where? Does the alarm reflect a trip or stage before the

trip?

Should the flag be self re-setting or

must it be manually re-set?

Low oil level main tank 1 No Self Re-setting Yes Annunciater Relay Panel N/A Manual Low oil level TC tank 1 No Self Re-setting Yes Annunciater Relay Panel N/A Manual Main tank Pressure Relief Operated

1 Yes Self Re-setting

Buchholz Main Tank 2 Yes Self Re-setting Yes Annunciater Relay Panel Before Manual

Oil temperature 3 Yes Self Re-setting Yes Annunciater Relay Panel Before Manual

Winding temperature 3 Yes Self Re-setting Yes Annunciater Relay Panel Before Manual

Buchholz (surge only) tap changer OR

1 Yes Self Re-setting No

Tap Changer Pressure control

1 Yes Self Re-setting No

Tap-change not commenced 1 No Self Re-setting Yes Annunciater RTCCP Neither Manual Tap-change out of step 1 No Self Re-setting Yes Annunciater RTCCP Neither Manual Taps not complete 1 No Self Re-setting No Faulty mechanism 1 No Self Re-setting No

VT supply fail 1 No Self Re-setting Yes Annunciater RTCCP Neither Manual

Fire sprinklers operated No Taps faulty No

AC Supply fail 1 No Self Re-setting Yes Annunciater RTCCP None Manual

Cooler supply fail 1 No No

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TABLE 1 (continued) – POWER TRANSFORMER ALARM AND INDICATION REQUIREMENTS

Substation Trip Indications SCADA

10 11 12 13 14 15 16 17 18 19

Yes/No How? Where?

Does the alarm reflect a trip or

stage before the trip?

Should the flag be self re-setting or must it be

manually re-set?

Required? How? SCADA from

where?

Should the contacts for SCADA be self re-setting or must it be manually re-set?

Does the alarm reflect a trip or

stage before the trip?

Low oil level main tank Yes X600, X601 Relay Panel Self Re-setting Neither Low oil level TC tank Yes X600, X601 Relay Panel Self Re-setting Neither

Main tank Pressure Relief Operated

Yes Annunciater or flagged

repeat relay Relay Panel Trip Manual Yes X600, X601 Relay Panel Self Re-setting Trip

Buchholz Main Tank Yes Annunciater or flagged

repeat relay Relay Panel Trip Manual Yes X600, X601 Relay Panel Self Re-setting Before

Oil temperature Yes Annunciater or flagged


Winding temperature Yes Annunciater or flagged


Buchholz (surge only) tap changer OR



Tap Changer Pressure control



Tap-change not commenced Yes X600, X701 RTCCP Self Re-setting Neither Tap-change out of step Yes X600, X701 RTCCP Self Re-setting Neither Taps not complete No Yes X600, X701 RTCCP Self Re-setting Neither Faulty mechanism No No

VT supply fail No Yes X600, X701 RTCCP Self Re-setting Neither

Fire sprinklers operated No No Taps faulty No No

AC Supply fail No Yes X600, X701 RTCCP Self Re-setting

Cooler supply fail No Yes X600, X701 RTCCP Self Re-setting

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4.11.7 Relays and Lamps Flush-mounting withdrawable pattern rear-connected relays will be preferred. Instruments shall be flush-mounted and rear-connected. Incandescent indicating lamps are to be wired in series with a resistor that will reduce the lamp voltage to approximately half the rated voltage of the respective lamp. Multi-element LED type lamps or displays are to be sufficiently bright to enable easy viewing under normal daylight conditions. 4.11.8 Alarm, Control and Tripping Contacts 4.11.8.1 General Alarm and tripping contacts shall be provided with electrically independent and unearthed circuits and shall be insensitive to vibration and earth tremors. This insensitivity shall not depend on the method of mounting, but shall be an inherent feature of the contact assembly. Auxiliary relays shall not be used. 4.12 Current Transformers 4.12.1 Standard The current transformers shall comply with the requirements of IEC 185. (Refer to Clause 7.1.3). 4.12.2 Location Current transformers (other than CT’s for the HV and LV neutral connections) are to be accommodated within the transformer tank either by fitting them over the internal under-oil portion of the bushing or by locating them above the core and winding assembly. 4.13.3 LV Winding The following CT’s shall be fitted on the LV winding; - 4.12.3.1 Current transformer required for operation of the tap-change control apparatus; 4.12.3.2 Current transformer required for operation of a hot spot device operating the winding

temperature indicator; 4.12.3.3 Protection and indication current transformers, if called for in the Contract Specification, shall

be suitable in all respects for the type of protection they are required to operate, in conjunction with any other existing CT’s in the same protection scheme.

4.12.4 HV Winding One CT is required for operation of a hot spot device driving the winding temperature indicator. 4.12.5 HV and LV Neutral Connections The neutral CT’s shall be externally mounted on the transformer tank adjacent to the respective neutral bushing. The CT’s shall be mounted in an oil-filled chamber with a bushing entry or, alternatively, cast resin CT’s may be supplied. The enclosure must be waterproof and the primary connections shall be suitable for connection to the copper conductors.

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If neutral CT’s are not called for in the Contract Specification, suitable brackets for mounting an external neutral CT are to be fitted to the transformer tank adjacent to the LV neutral bushing. Transformers with 132 kV windings are also to be provided with a bracket adjacent to the HV neutral bushing for mounting an external neutral CT. 4.12.6 Wiring All current transformer secondary connections must be wired to terminals in the marshalling kiosk. All secondary connection leads of any one winding must be routed through the same trunking or conduit. 4.13 Voltage Transformers The voltage transformers, where called for in the Contract Specification, shall comply with the requirements of IEC 186: 1975. Outdoor voltage transformers shall be suitable for operation under the atmospheric conditions as specified in the General Conditions of Contract or Contract Specification. 4.14 Internal Small Wiring 4.14.1 Insulation Under-oil small wiring shall be carried out in stranded copper wire thoroughly insulated with a material that will retain its insulating properties indefinitely under oil. The thermal characteristics of the wiring shall be equal to Class A of IEC 85. 4.14.2 Type of Conductor The small wiring of the driving mechanism cubicles, remote tap-change control panel and marshalling kiosk shall be in 250 volt, Grade PVC, insulated wire of not less than 2,5mm2 stranded copper conductor to SABS 150 and shall be clearly labelled to identify the respective circuits. 4.14.3 Fixing and Marking of Wiring The wiring is to be supported clear of metal work in a neat orderly fashion. Numbered ferrules corresponding with the wiring diagrams are to be provided at each end of each wire. Unless otherwise approved, the ferrules shall be white with black figures. Wires are to be terminated with compression lugs where not more than two wires shall be connected to any one terminal. The wiring shall be fixed to terminals with washers, nuts and lock-nuts or spring-washers and lock-nuts. 4.14.4 Terminal Boards Under-oil terminal boards are to be engraved for easy identification of the respective circuits. Terminal boards shall be mounted to give easy access to the terminals and numbered ferrules and they shall also be placed close to the corresponding externally mounted multi-core terminal boxes. (Refer to Clause 4.16).

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4.14.5 Terminal Boxes Terminal boxes are to be provided with detachable weatherproof covers and shall be provided with appropriate gland plates and sufficient space for incoming and outgoing cables. 4.14.6 MCB Protection Miniature circuit breakers bearing the SABS mark shall be provided for sub-circuit protection. The MCB’s shall have a short circuit rating of 10 kA. 4.15 Secondary Wiring Terminals The terminals shall be of the spring-load type, similar or equal to Klippon Type RSF1. Covers marked “Danger” are to be provided over any terminals operating at or above 400 volts. 4.16 Multi-Core Cables The Purchaser will supply multi-core cables and appropriate glands for cable runs between the marshalling kiosk and remote tap-change control panel. The contractor is to provide facilities for securing the terminating glands and multi-core cables for all small wiring inter-connections. Multi-core cables will be to SABS 150 in 2,5mm2, 7 core or 14 core sizes insulated with 600 volt Grade PVC unless otherwise agreed with the successful tenderer. Multi-core cables supplied by the contractor shall be supported clear of any metal work on the transformer. 4.17 Auxiliary Supply Voltages 4.17.1 Auxiliary AC Supply Voltages 400 V, 3 phase, 50 Hz (4 wire) or 230 V, single phase. 4.17.2 Auxiliary DC Supply Voltages The equipment offered in accordance with this Standard shall be suitable for the auxiliary DC supply voltages given in the tender contract specification. In order to reduce battery drain, all DC voltages are reserved for circuit breaker tripping and in this Standard; the DC will only be taken to alarm indicating relays on the tap-change panels. 4.18 Neutral Earthing Conditions 4.18.1 System Neutral Earthing The transformer will be operated in a built-up area for stepping down a three phase high voltage supply in order to supply a three phase distribution network. The system voltages at which the transformer must operate shall be given in the Contract Specification. Earthing details of the present system are as follows: -

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The neutral points of the 132 and 66 kV systems are solidly earthed.

The neutral point of the 22 kV system is earthed through a 6 ohm resistor.

The neutral point of the 11 kV system is earthed through a 3 ohm resistor.

The neutral point of the 6,6 kV system is earthed through a 1,9 ohm resistor. 4.18.2 Transformer HV and LV Neutral Earthing The HV neutral point of the transformer up to and including 66 kV will not be earthed. The HV neutral point of all star connected windings operating at voltages greater than 66 kV will be solidly earthed. The LV neutral point of the transformer will be earthed as stated in the previous paragraph. Note that a common resistor is used to earth all transformers feeding they system supplied by the LV winding. 4.19 Fabrication Materials, Construction, Finish, Painting and Galvanising (Anti-Corrosion Treatment) 4.19.1 Power Transformer Tanks 4.19.1.1 Fabrication Material The steel used shall be as called for in Clause 4.5.1.1. 4.19.1.2 Pre-Treatment Rust and millscale on internal and external plates, surfaces and sections shall be removed prior to fabrication by means of sand or shot-blasting. Tubular sections are to be cleaned by acid pickling. Post fabrication treatment must embrace grinding, deburring and polishing, followed by an internal and external high pressure degreasing iron phosphate wash of the entire tank assembly. 4.19.1.3 Painting (Externally) The complete tank, covers, core clamps and all mechanical accessories shall be given one coat of high-build polyurethane primer. Exterior surfaces must then be painted with intermediate and finishing coats of Polyurethane Acrylic Gloss-Enamel applied in alternate coats of contrasting colours until the required thickness of paint is obtained. (Contrasting colours will ensure complete coverage). Required thickness – Coastal finish = 125m (total). A coastal finish is imperative as the transformers are to be installed in areas subject to severe coastal corrosive pollution. Standard Final Colour: - Dark Admiralty Grey – SABS 1091: 1975 (Ref No. G12). 4.19.1.4 Painting (Internally) The inside of the entire tank assembly shall be treated with one application of white coloured “Intergard” EB Series/EBA 962 HB Epoxy Primer or an approved equivalent. (This will protect the metal surfaces until such time as the unit is filled with oil).

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4.19.1.5 Bolts, Nuts and Washers All nuts, bolts and washers on the tank and associated equipment are to be hot dip galvanised to SABS 763. NOTE: Galvanised bolts must not be used on bare stainless steel or 3CR12; in such cases stainless steel bolts, nuts and washers are to be fitted. (Electrolytic corrosion possibility). 4.19.2 Oil Conservator 4.19.2.1 Fabrication Material The steel used shall be as called for in Clause 4.5.1.1. 4.19.2.2 Painting (Externally) The conservator external surfaces and inter-connecting pipe work, after pre-treatment, as per 4.19.1.2, shall be treated and given the same external paint finish as the transformer tank. Final colour shall be Cloud White – SABS 1091: 1975 (Ref No. G80). NOTE: The white colour reduces atmospheric heat gain to the conservator. 4.19.2.3 Painting (Internally) The conservator and inter-connecting pipe work internal surfaces, after pre-treatment as per 4.19.1.2, shall be treated as required in Section 4.19.1.4. 4.19.3 Radiators and Cooler Banks 4.19.3.1 Fabrication Material The steel used shall be as called for in Clause 4.5.1.1. 4.19.3.2 Galvanising (Externally) Radiators and coolers are to be thoroughly cleaned by sand or shot-blasting or acid pickling, as applicable, internally and externally. All radiators shall be externally heavy duty galvanised to SABS 763. 4.19.3.3 Painting (Externally) Radiators and cooler banks are to be externally painted at the factory directly after galvanising as recommended by “The Hot-Dip Galvaniser’s Association of Southern Africa” and described below. The following procedure shall be followed: -

Galvanised coatings must not be passivated by the galvaniser after galvanising.

Clean all steel with a galvanised iron cleaner to a water break free surface.

Rinse off all traces of cleaning chemical by means of a high pressure hose (tap pressure).

Apply one coat (40 to 50m) of Plascon Gehopen GW5 epoxy primer or approved equivalent e.g. Dulux Sigmacover primer.

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Apply two coats Plascon polyurethane CPC series or equivalent (total thickness 60m). Note: paint application by flow coating is acceptable.

Material should preferably be painted at the galvanising works immediately after application of

the galvanising.

After erection, all galvanised fasteners must be over coated with paint to ensure equal protection to that applied to the rest of the assembly.

Standard final colour: Dark Admiralty Grey – SABS 1091: 1975 (Ref No. G12).

4.19.3.4 Painting (Internally) The internal surfaces of all radiators and cooler bank assemblies, after pre-treatment as per clause 4.19.1.2, shall be coated with a red oxide primer. (This will protect the metal surface until such time as the unit is filled with oil). 4.19.4 Hot Oil-Tightness Test The entire transformer tank and radiator assembly and cooler banks, if any, are to be fully tested for hot oil-tightness under pressure before finishing. 4.19.5 Mounting Brackets/Angles/Clamps/Fixing Pieces etc. (External) All steel fixings for the mounting of any accessory components on the transformer tank structure and cooler assembly shall be heavy duty galvanised to SABS 763 and then painted as per Clause 4.19.3.3 to the final applicable colour. 4.19.6 Outdoor Panels, Cubicles, Marshalling Boxes, Junction Boxes and Kiosks etc. (Including the Tap-Change Control Panel/Motor Drive Housing on the Transformer) 4.19.6.1 Construction Cubicle housings etc. shall be of sufficient gauge to ensure rigidity and the final product shall be of neat and attractive appearance. The cubicles are to be adequately weatherproof and must be fully vermin proof. 4.19.6.2 Fabrication Material All outdoor cubicles etc. shall be manufactured from either stainless steel or 3CR12; if 3CR12 is used the manufacturing process shall be strictly in accordance with the requirements laid down in “The Columbus Stainless 3CR12 User Manual”, whilst for stainless steel the requirements of the steel manufacturer/supplier shall be adhered to. 4.19.6.3 Bolts, Nuts and Washers All nuts, bolts and washers used on outdoor panels, brackets, clamps, etc. shall be of stainless steel. 4.19.6.4 Finish All outdoor cubicles etc. shall be either electrostatic-powder painted or conventially painted strictly in accordance with the requirements / recommendations laid down in “The Columbus Stainless 3CR12 User Manual”.

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If stainless steel is used, the paint process shall be in accordance with the requirements / recommendations of the steel manufacture / supplier. Standard external final colour: Dark Admiralty Grey – SABS 1091: 1975 (Ref No. G12). Standard internal final colour: Light colour having anti-condensation properties. 4.19.7 Indoor Panels, Cubicles and Junction Box Equipment etc. (Including Tap-Change Control Panel) 4.19.7.1 Construction Panel housings shall be of sufficient gauge to ensure rigidity and the final product shall be of neat and attractive appearance. The panels are to be fully vermin-proof. (See Clause 4.11.4.1). 4.19.7.2 Fabrication Material Mild steel (see Clause 4.11.4.1). 4.19.7.3 Pre-Treatment All components should be acid pickled and zinc phosphated after fabrication. 4.19.7.4 Painting Components are to be electrostatic-powder painted according to Table 2 of SABS 1274: 1979, requirements for type 2 coating for interior use. Standard external final colour: Light Grey – SABS 1091: 1975 (Ref No. G29). Standard internal final colour: Light colour having anti-condensation properties. 4.19.8 Alternative Painting Methods Alternative paint specifications will be considered and their use is subject to prior approval. 4.19.9 Damage to Paintwork The contractor shall make good any damage to paintwork on the transformer and its associated outdoor apparatus after erection on site using paint supplied in unopened tins. The repair work shall be done in such a manner as to give protection to the factory finish. 4.19.10 Anti-Corrosion Guarantee In addition to any other guarantees offered, implied or called for, the manufacturer of the transformer shall guarantee to maintain, repair or replace, at his own cost, within 90 days of written notification, any components of the transformer or associated equipment supplied as part of the unit, which may, by reasonable standards, be regarded as showing signs of corrosion within a period of three (3) years from date of hand-over / acceptance of the transformer. Any components repaired or replaced in terms of this clause are also to be guaranteed for a period of three (3) years commencing from the date of completion of the repair or replacement.

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Should the manufacturer / supplier of the equipment fail to satisfactorily honour the obligations under this clause in the event of being called upon to do so, then the Council shall arrange for any necessary remedial work to be carried out, and shall invoice the manufacturer accordingly for all costs incurred, including administration and personnel costs. 4.20 Transport and Erection 4.20.1 The tenderer will be responsible for co-ordinating the arrangements for all stages of the

transport of the transformer from the manufacturer’s works to site. 4.20.2 The transformer is to be transported to site with a small positive pressure of dry nitrogen in

the tanks. A gauge must be fitted to indicate the pressure. 4.20.3 Erection shall include off-loading, lifting, handling, filling with oil, positioning on foundations

prepared by the Purchaser and pre-commission site testing of the transformer. 4.20.4 The successful tenderer must supply and install two layers of 5 ply bituminous felt under the

transformer. 4.20.5 A 400 volt, 3 phase, 4 wire, 50 Hz supply will be available on site for commissioning

purposes. The contractor shall provide his own wiring from the point of supply. 4.21 Labels 4.21.1 General All apparatus is to be clearly and indelibly labelled to ensure correct operation and safety both to the plant and to the operators. Labels shall be provided for all apparatus such as relays, switches, fuses, and etc. contained in a cubicle, kiosk or panel. Labels not exposed to the weather shall be of engraved laminated Traffolyte or equal approved black material having white lettering or, in the case of danger notices, it shall have red lettering on a white background. Labels exposed to the weather, including the transformer rating and diagram plates, shall be of stainless steel or equivalent with all information permanently applied by etching, engraving or stamping. All lettering shall be of ample size and clearly legible and all labels shall be attached by means of screws, bolts and nuts or pop rivets. Labels and diagram plates should be offset from the apparatus to which they are fixed so that water may not collect between the two surfaces. 4.21.2 Rating and Diagram Plates Rating and diagram plates complying with Clause 4.21.1 shall be fitted at approximately 1,50m (to the centre line) above ground level by means of straps fixed clear of the tank or to the tank stiffeners. The rating plate shall include all the relevant data specified in IEC 76 as well as the percentage zero sequence impedance.

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The diagram plate shall include the vector diagram and winding diagram of the transformer with terminals lettered and / or numbered to correspond, also the tap sequence list with voltages and position numbers and other relevant information. Where current transformers are built into the transformer, details of their location, polarity and secondary terminal markings shall be stamped on the diagram plate. 4.22 Gasket Material 4.22.1 All gaskets shall be of approved material to make oil-tight joints and a spare set shall be

provided where necessary for use in the assembly of the transformer on site. 4.22.2 Oil-resisting synthetic rubber shall not be used except as a bonding medium for cork or similar

material. 4.23 Vibration and Noise The transformer and all auxiliary plants shall be designed and manufactured such that, when operating at any load on any tapping with either the nominal or higher than nominal voltages applied in accordance with this specification, the sound level emitted shall not exceed 76 dBthe in accordance with the NEMA Publication No. TR 1-00-06. (Refer to Clause 7.1.2). 4.24 Spares and Special Tools Tenderers are to quote for any spares and special tools, which are considered necessary for maintaining the equipment in service. If bolts or nuts are so placed as to be inaccessible with ordinary spanners, suitable special spanners shall be supplied. 4.25 Insurance 4.25.1 Insurance Provided by the Council Insurance in respect of the work will be arranged in accordance with the Council’s General Conditions of Contract, the Supplementary Conditions of Contract and the Council’s Insurance Policy, a copy or further details of which are available from Price Forbes Federale Volkskas (Eastern Cape) (Pty) Ltd, PFV House, Greyville Road, Greenacres, Port Elizabeth. The Council will arrange riot Insurance equal to the Contract Value. The tenderer is requested not to make provision for these insurances except to the extent that he considers it necessary to effect supplementary cover. Full details of and reasons for any such supplementary cover must be given in the tender Schedule of Particulars and Guarantees. 4.25.2 Insurance Provided by the Contractor Insurances to be provided by the contractor and / or sub-contractors in terms of the General and / or Special Conditions of Contract before commencing work include, but are not limited to, Professional Indemnity Insurance. The contractor shall guarantee that the entire works will perform in accordance with the specification, which guarantee shall be supported and underwritten by an insurer approved by Council. The liability provided by the contractor’s insurer should remain indefinitely.

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The minimum indemnity limit provided by the contractor’s insurance policy shall be R5 000 000 per event. The contractor’s liability is not, however, limited by this insurance. 5. QUALITY 5.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 5.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 6. DRAWINGS 6.1 General All drawings shall be to scale and fully detailed. All important dimensions shall be given. Drawings for approval shall be submitted in triplicate and the contractor shall supply any further copies upon request. The original drawings shall be prepared in such a manner that they comply fully with the requirements of SABS 0111 and in order that acceptable microfilm versions can be made there from. 6.2 Drawings to be submitted with Tender The following is a list of the drawings for each type of transformer, which must be submitted with the tender: - 6.2.1 A preliminary outline drawing showing side and end elevations (both higher and lower voltage

sides) and plan of the tank including main terminals and cooling equipment. Parts to be removed for transport shall be indicated.

6.2.2 Drawings giving typical mechanical and electrical details of the on-load tap-changer voltage

control, including a detailed description of the voltage control operation of the tap-changer. 6.2.3 Diagrams of connection showing the method of cooler control. 6.3 Drawings to be supplied within Three Months of the Date of Order The following drawings are to be supplied by the contractor within three months of the date of order: - 6.3.1 Outline and general arrangement drawing including details of the masses and loadings. 6.3.2 Details of the underbase and jacking points.

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6.4 Drawings to be supplied before Manufacture is Commenced The following drawings are to be supplied by the contractor before manufacture is commenced: - 6.4.1 Details and diagram of connections of the temperature control, alarm and trip circuits and

devices. 6.4.2 Diagrams of connections of transformer and tap-change voltage control apparatus showing

exact ratios and BS Vector Group. 6.4.3 Details of bushings, cable boxes and fittings, including current transformers and the provision

made for them. 6.4.4 General arrangement of the remote tap-change control panel. 6.4.5 Detail drawings of the cooling plant. 6.4.6 Drawing(s) of any special features likely to need any special attention during inspection,

testing, maintenance or repair. 6.4.7 Cable schedules indicating cable sizes, wire numbers, spare cores, etc. 6.5 Maintenance Manuals Four copies of maintenance and operating instruction booklets for the transformer and associated equipment are to be submitted before delivery of the transformer. 7. TESTS 7.1 Test Certificates 7.1.1 Routine Tests The transformer is to be routine tested in accordance with IEC 76 unless otherwise specified. Certificates showing the test results are to be submitted for approval. Test results shall be in agreement with the figures guaranteed in the tender. Attention is drawn, however, to Clauses 3.3 and 3.4 covering penalties and rejection of the transformer. 7.1.1.1 Measurement of Load Losses and Impedance The load losses and impedance shall be measured in accordance with IEC 76 on each transformer. The measurement shall be performed on the principal tapping position and the two extreme tapping positions at the rated current of the respective tapping. The following details shall be recorded under the heading of Load Losses on the test certificate: -

(a) Voltage measured across the phases.

(b) Currents measured in each phase.

(c) Total losses measured

(d) Total losses corrected to 75oC.

(e) Top and bottom oil temperature.

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7.1.1.2 Measurement of No-Load Losses and Current The no-load losses and the no-load current of each transformer shall be measured as specified in IEC 76. The guaranteed value of the no-load losses, as completed in the tender Schedule of Particulars and Guarantees, shall be that incurred by the application of rated voltage. In each case, the measurements shall be made at 90%, 100% and 110% of rated voltage. The following details shall be recorded under the heading of no-load losses on the test certificate: -

(a) The terminal markings of the terminals supplied with power.

(b) The voltmeter readings taken on each voltmeter on each phase.

(c) The mode of response and scaling of the voltmeters.

(d) The current readings taken on each phase.

(e) The power readings taken on each phase.

(f) The frequency reading.

(g) The instrument constants and corrections.

(h) Corrections made to power and current results due to non-sinusoidal wave forms of voltage and current.

(i) The magnetisation curve of the transformer.

7.1.2 Type and Special Tests Copies of up to date certified Type and Special Test Certificates shall be submitted with the tender, showing that transformers of identical construction have undergone a temperature rise test within the guarantees and that transformers of identical core and coil construction have successfully withstood the specified impulse withstand voltage tests. The sound level produced by the transformer and forced air-cooling apparatus, where applicable, shall be measured in accordance with IEC Publication No. 551 and / or NEMA Publication No. TR1. Full details of the arrangements and conditions of the tests shall be recorded on the test certificates. The zero sequence impedance test shall be in accordance with IEC 76. Certificates showing the test results are to be submitted for approval. If such Type and Special Test Certificates are not available, the cost of such testing is to be included in the Contract Price. 7.1.2.1 Temperature Rise Measurement The temperature rise tests shall be carried out in accordance with IEC 76 except that the losses supplied to the transformer during the tests shall be not less than 95% of the losses measured in terms of Clause 7.1.1.1 on the principal tap and Clause 7.1.1.2. 7.1.3 Current and Voltage Transformers Current and voltage transformers are to be tested for accuracy in accordance with IEC 185 and IEC 186 respectively. Test Certificates must be supplied in duplicate and must indicate the errors obtained at the particular test burden and current.

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7.1.4 Testing of Associated Equipment Bushings shall be tested in accordance with the recommendations of BS 223, SABS 1035 and IEC 137. On-load tap-changers shall successfully sustain the type and routine tests as specified in BS 4571. The gas and oil-actuated relays and devices with alarm and tripping contacts shall be tested to confirm their accuracy in accordance with the manufacturer’s recommendations. 7.1.5 Calibration of Test Instruments The tenderer shall detail in writing the frequency of calibration of the test instruments used for the measurement of load and no-load losses. The tenderer must also state which authority performed the calibration. Such certificates must be available for inspection by Council if required. 7.2 Internal Pressure and Vacuum Tests 7.2.1 Pressure Tests The tank, conservator and associated cooling apparatus shall be capable of withstanding an internal hydraulic pressure of 70 kPa or the maximum operating pressure plus 35 kPa, whichever is the greater, without suffering permanent deflection measured after a first application in excess of the amounts specified in Table 2 below. The complete transformer shall be tested for hot oil leaks. 7.2.2 Vacuum Test It must be possible to draw a vacuum of 500mm of mercury (i.e. 70 kPa less than atmospheric pressure) on the transformer tank when filling with oil, after erection on site. Any reasonable temporary reinforcement of the tap-change terminal board or explosion vent during this process will be agreed with the contractor.

TABLE 2 – MAXIMUM PERMANENT DEFLECTION OF STEEL TANK PANELS

Minor Dimension of Panel between Stiffeners

mm

Maximum Permanent Deflection

mm

Exceeding 3 000 Exceeding 2 700 but not exceeding 3 000 Exceeding 2 300 but not exceeding 2 700 Exceeding 2 000 but not exceeding 2 300 Exceeding 1 650 but not exceeding 2 000 Exceeding 1 300 but not exceeding 1 650 Exceeding 950 but not exceeding 1 300 Exceeding 750 but not exceeding 950 Exceeding 600 but not exceeding 750 Exceeding 450 but not exceeding 600 Below 450

16 14 12 10 8 6 4 3 2 1 0

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POWER TRANSFORMERS


REV NO.

DETAILS

AUTHOR


5

Format changed to PEM Standard and renumbered Amendments to: - References now use IEC Stds in preference to BS Secondary Terminals Routine Test Tolerances Minor Textual Corrections

MB

September 1994

6

Section 4.9.2 – Cable Sealing Boxes up to 22 kV Added paragraph – Cable Boxes to be fitted with vent pipes

DMM

30 August 1995

7

Section 4.9.5 – Disconnecting Chambers Now required for all windings of 6,6 kV and above (was 22 kV and above) Added Clause 4.4.3 PCB content in oil Clause 4.10.1 Removed requirement for “Arcing Horns” on bushings Added Clause 4.10.1.1 Surge Arresters now called for

BAZ

22 January 1996

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8

Clause 4.10 (General Comment) Slightly more detail regarding this Department’s particular requirements for bushings has been added Clause 4.10.3 The requirement that the neutral bushing on the HV side be interchangeable with the phase bushings removed

BCF

19 August 1997

4.10.3.2 The need to make provision for fitting a neutral bushing at a later date has been removed Clause 4.11.2 Switch compartment (design of the tap-changer) This entire section has been replaced. It now more clearly sets out this Department’s requirements Clause 4.11.8 Alarm, Control and Tripping Contacts This has been added as extra information for tenderers Clause 4.19 Fabrication and Finish This entire section has been replaced. It now more clearly sets out this Department’s requirements An “Anti-corrosion” guarantee has been included (4.19.10)

9

Amended following Sections: 4.11.4.2 4.11.5 4.11.6 Added Table 1, renumbered old Table 1 as Table 2

PG 29 April 2005

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OUTDOOR TYPE CURRENT TRANSFORMERS FILED-F:\DATA\STANDARDS\PEE_STD\STD 105 – OUTDOOR TYPE CURRENT TRANSFORMERS\Std 105.doc




________________

OUTDOOR TYPE CURRENT TRANSFORMERS

____________________________

REV – DRAFT 2 12 FEBRUARY 2001

of 8



BLANK PAGE

of 8







TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5 2.1 Standards

3. VARIATIONS FROM AND ADDITIONAL TO NRS 029 SPECIFICATION 5 3.1 Service Conditions 3.2 Basic Insulation Level 3.3 Capacitive Taps 3.4 Metal Finish 3.5 Multi-Ratio Current Transformers 3.6 Core Steel Details 3.7 Nominal Short-Duration Primary Current 3.8 Conductor Attachment Clamps 3.9 Rating and Diagram Plates 3.10 Tests and Test Results

4. PARTICULARS OF THE DISTRIBUTION SYSTEM 6

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PAGE 5. QUALITY 7 5.1 General 5.2 Quality Assurance Provisions

6. DRAWINGS 7

7. LITERATURE 7

8. SPARES AND SPECIAL TOOLS 7

9. INSTALLED USER BASE 7


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1. SCOPE This Standard provides for the design, manufacture and works testing of outdoor type current transformers. The purchaser will install the current transformers and will supply and install all cables to interconnect with remote equipment. 2. REFERENCES 2.1 Standards The current transformers shall, unless otherwise specified, be manufactured and tested in accordance with the relevant requirements of the Standards listed hereunder: - NRS 029: 1993 : Outdoor Type Current Transformers

SABS 0111 : Part 1 – Engineering Drawing – General Principles

SABS 763 : Hot-dip (Galvanised) zinc coatings (other than on continuously zinc-coated

sheet and wire)

SABS ISO 9000 : Quality Systems

BS 3938 : Current Transformers 3. VARIATIONS FROM AND ADDITIONS TO NRS 029 3.1 Service Conditions The current transformers shall be suitable for use under conditions of heavy coastal salt pollution. (See Council’s General Conditions of Contract). The minimum specific creepage distance between phase and earth shall be 25mm per kV of Um.

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3.2 Basic Insulation Levels See the NMMM departmental Code of Practice Number 3.3. 3.3 Capacitive Taps Capacitive taps for dielectric loss factor (tangent delta) testing are not required. 3.4 Metal Finish All ferrous parts associated with the current transformers shall be hot-dip galvanised in accordance with SABS 763. 3.5 Multi-Ratio Current Transformers Multi-ratio current transformers shall provide ratios as called for in the Schedule of Particulars and Guarantees. Rated burden and accuracy class shall apply to the lowest specified ratio. 3.6 Core Steel Characteristics for Measuring Current Transformers The characteristics of core steels used for measuring transformers shall be such that an Instrument Security Factor of less than eight will be achieved; i.e. the current transformer must saturate at a primary current of less than eight times the specified value of primary full load current. 3.7 Nominal Short-Duration Primary Current These values shall be as called for in Item D4 of the Schedule of Particulars and Guarantees. 3.8 Conductor Attachment Clamps Clamps are not required. 3.9 Rating and Diagram Plates The nameplate details for Class “x” current transformers shall be as specified in BS 3938. 3.10 Tests and Test Results 3.10.1 Certified copies of test certificates, showing the results of type tests performed on equipment

similar to that offered are to be included in the tender. 3.10.2 Routine tests are to include measurement of dielectric loss factor (tangent delta). 3.10.3 No special tests or HV tests on site are required. 4. PARTICULARS OF THE DISTRIBUTION SYSTEM The current transformers will be installed on a three phase, three wire, 50 Hz system with an effectively earthed neutral. The phase sequence is non-standard, i.e. R-B-Y-R.

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5. QUALITY 5.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal internationally accepted industry expertise is expected throughout. 5.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 6. DRAWINGS The original drawings shall be prepared in such a manner that they comply with the requirements of SABS 0111, in order that acceptable microfilm versions can be made from them. 7. LITERATURE Descriptive literature and drawings showing dimensions must accompany the tender offer. 8. SPARES AND SPECIAL TOOLS Tenderers shall quote for any spares, which are recommended and any special tools necessary for replacing any part that may become defective. The tenderer must indicate what repair facilities are available in South Africa. 9. INSTALLED USER BASE Tenderers must state how long the equipment offered has been in production, along with the names and addresses of at least two South African users who can be contacted for comment on the equipment.

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REV NO.

DETAILS

AUTHOR


1

Original First Draft Issue

MTO BCF

December 1994

2

Put into standard Word Format

KP

12 February 2001

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REV – 2 24 MAY 2002PEE STANDARD NO: 106

6,6/11kV OIL COOLED OUTDOOR NEUTRAL EARTHING RESISTORS FILED-F:\DATA\STANDARDS\PEE_STD\STD 106 – NER’s (OIL COOLED)\Std 106.doc




________________

MV METALLIC, OIL COOLED OUTDOOR

NEUTRAL EARTHING RESISTORS (6,6kV, 11kV and 22kV)

____________________________

REV – 2 24 MAY 2002

of 13



BLANK PAGE

of 13






MV METALLIC, OIL COOLED OUTDOOR NEUTRAL EARTHING RESISTORS

(6,6kV, 11kV and 22kV)

TABLE OF CONTENTS

PAGE 1. SCOPE 6

2. REFERENCES 6 2.1 General Conditions of Contract 2.2 Standards

3. REQUIREMENTS 7 3.1 Service Conditions 3.2 Insulation Levels 3.3 Physical Arrangement 3.4 Breather 3.5 Buchholz Relay 3.6 Insulating and Cooling Liquid 3.7 Liquid Level Gauge 3.8 Drain Valve 3.9 Liquid Filling Pipe 3.10 Lifting Lugs 3.11 Bushings 3.12 Main Terminals

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PAGE 3.13 Conductor Connections 3.14 Mounting 3.15 Corrosion Proofing and Finishing

4. OTHER FITTINGS 8 4.1 Temperature Indication 4.2 Pressure Relief Device

5. TERMINAL BOX 9

6. CURRENT TRANSFORMER 9

7. RATING PLATE 9

8. DESIGN DETAILS 10 8.1 Ratings 8.2 Insulation Levels 8.3 Temperature Rise Limits 8.4 Temperature Co-efficient of the Resistor Material 8.5 Short-Time Current

9. TESTS 10 9.1 Resistance Test 9.2 Applied Voltage Test 9.3 Temperature Rise Test 9.4 Test Certificates


11. DRAWINGS 11

12. LITERATURE 11



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MV METALLIC, OIL COOLED OUTDOOR NEUTRAL EARTHING RESISTORS

(6,6kV, 11kV and 22kV)

1. SCOPE This Standard provides for the design, manufacture and testing before despatch of metallic, oil cooled neutral earthing resistors (NER’s), for outdoor use on the 6,6kV, 11kV and 22kV distribution systems. The purchaser will install the NER’s and will supply and install all cables to interconnect with remote equipment. 2. REFERENCES 2.1 Conditions of Contract The equipment and materials covered by this Standard shall be supplied in accordance with the Council’s General Conditions of Contract attached hereto. 2.2 Standards Unless otherwise specified herein, the NER’s shall be manufactured and tested in accordance with the following Standards: - SABS 555 : Mineral Insulating Oil for Transformers and Switchgear (Uninhibited)

SABS 780 : Distribution Transformers

SABS 1035 : Insulated Buildings

SABS 1037 : Standard Transformer Bushings

SABS 1091 : National Colour Standards for Paint

IEC 156 : Method for the Determination of the Electric Strength of Insulating Oils

IEC 296 : Specification for Unused Mineral Insulating Oils for Transformers and Switchgear

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3. REQUIREMENTS 3.1 Service Conditions The NER’s shall be suitable for use under conditions of heavy coastal salt pollution. The minimum specific creepage distance between phase and earth shall be 25mm per kV of Um. 3.2 Insulation Levels

STANDARD VOLTAGES AND INSULATION LEVELS

Highest rms voltage for

equipment

Um (kV)

Nominal system rms

voltage

Un (kV)

Rated lightning impulse peak withstand voltage

(kV)

Rated short-duration (60 second) power

frequency rms withstand voltage

(kV)

7,2 12 24

6,6 11 22

75 95 150

22 28 50

3.3 Physical Arrangement The resistor shall be immersed in transformer oil contained in a free-breathing steel tank equipped with a conservator of adequate capacity. Both electrical end connections of the resistor element shall be brought out to external terminals via open bushings. 3.4 Breather A suitably sized silica gel breather shall be provided and fitted to the conservator tank. 3.5 Buchholz Relay An appropriate Buchholz relay shall be provided and suitably mounted in the pipe between the main tank and the conservator tank. 3.6 Insulating and Cooling Liquid The resistor tank and conservator shall be delivered filled to the normal level with unused dry transformer oil, which shall comply in all respects with the requirements for Class 1 oil contained in IEC 296 and shall contain no additives. 3.7 Liquid Level Gauge A direct reading liquid level gauge, as specified in SABS 780, shall be provided on the conservator. 3.8 Drain Valve A drain / sampling valve shall be provided at the base of the main tank.

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3.9 Liquid Filling Pipe A liquid filling pipe and cap shall be provided (see SABS 780). 3.10 Lifting Lugs Lifting lugs shall be provided on the tank, for lifting the complete unit, and on the cover plate for lifting the cover only. 3.11 Bushings Unless otherwise approved, bushings shall comply with the requirements of SABS 1035 and SABS 1037. 3.12 Main Terminals The incoming terminal shall be a solid plain copper cylinder 26mm in diameter and not less than 100mm in length. The terminal connected to the earthwards end of the resistor shall be provided with clamps suitable for undrilled 50mm by 3mm flat copper strap. 3.13 Conductor Connections Conductor connections shall be made by bolting, welding, brazing or crimping and shall be thermally stable and mechanically secure at all operating temperatures. 3.14 Mounting The resistor may be mounted on a steel structure to provide the necessary safety clearance from ground level; mounting holes shall therefore be provided as specified in SABS 780. The supply of the steel structure does not form part of this Standard. 3.15 Corrosion Proofing and Finishing The tank and cover plate shall have a corrosion resistant treatment and finish as specified in SABS 780, but the final colour shall be dark admiralty grey according to SABS 1091 / G12. 4. OTHER FITTINGS 4.1 Temperature Indication The top liquid temperature shall be indicated by means of an approved dial type thermometer, which must have a range of not less than 30oC to 150oC and provided with alarm and tripping contacts. The thermometer shall be mounted on the outside of the resistor tank wall at a safe height above the tank base. 4.2 Pressure Relief Device The unit shall be equipped with an approved spring operated pressure relief valve designed to minimise the possibility of rupture of the tank in the case of the period of flow of fault current through the resistor exceeding the rated short time, or any internal fault resulting in a dangerous pressure increase in the tank. This device shall be fitted with trip and alarm contacts and a visual operation indicator arranged for manual resetting.

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5. TERMINAL BOX A weatherproof terminal box with an adequately sized gland plate shall be provided and mounted on the outside of the resistor tank wall at a safe height above the tank base. The alarm and trip contacts on the following items shall be wired back to this terminal box: -

Buchholz Relay

Thermometer

Pressure Relief Device 6. CURRENT TRANSFORMER A standard current transformer shall be built into the resistor tank and connected between the earthwards end of the resistor and the insulated earth terminal. The current transformer shall have the rating specified in the Schedule of General Particulars and Guarantees. A dedicated weatherproof terminal box with an adequately sized gland plate shall be provided and mounted on the outside of the resistor tank wall at a safe height above the tank base. The current transformer secondary connections shall be wired back to this terminal box. 7. RATING PLATE The rating plate shall be of stainless steel and shall have engraved, embossed or stamped on it the various ratings and data as follows: -

CURRENT LIMITING RESISTOR

System nominal voltage (Un) Nominal voltage (Un / 1,73) Resistance at 100oC Nominal short time current (10 s) Maximum continuous current Nominal frequency Insulation levels (impulse / power frequency) Volume of oil

kVrms

kVrms

ohm

A

A

Hz

KVpk / kVrms

litre

Connection diagram (which shall show the neutral current transformer terminal markings and the resistor terminal markings as follows: - “N” for the terminal to be connected to the system neutral and “E”, together with the earthing symbol, for the terminal to be earthed).

A separate rating plate as per BS 3938 shall be provided to give the details of the current transformer.

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8. DESIGN DETAILS 8.1 Ratings The resistors shall have the various ratings specified in the Schedule of Particulars and Guarantees. 8.2 Insulation Levels The resistors shall be fully insulated throughout to withstand the test voltage specified in Clause 9.2. 8.3 Temperature Rise Limits 8.3.1 The temperature rise of the top liquid, resulting from the losses due to the passage of

maximum continuous current, shall not exceed 55oC. 8.3.2 The temperature rise of the resistor element, due to the passage of maximum continuous

current, shall not exceed 60oC. (Full load rated continuous current). 8.3.3 The temperature rise of the resistor element, after passing the nominal short-time current for

10 seconds from an initial temperature of 100oC (40oC ambient + 60oC rise from 8.3.2), shall not exceed 350oC, i.e. final maximum allowable temperature of 450oC.

8.4 Temperature Coefficient of the Resistor Material The temperature coefficient of the resistor material, with a temperature rise not exceeding the value specified under conditions described in Clause 8.3.3, shall ensure that the final resistance value of the metallic resistor will not be more than 106% of its initial value (at 100oC). 8.5 Short-Time Current The nominal short-time current of the neutral earthing resistor will be as specified in the Schedule of Particulars and Guarantees. The maximum value of the short-time current will, however, depend on the system voltage at the time of the fault (maximum value, Um, is 1,1 x Un) and on the actual impedances of the supply transformer and also on the actual initial temperature of the resistor. The maximum value of the short-time current to be expected in service may thus exceed the nominal short-time current by 15% of its value. The purchaser will accept this increased short-time current over a correspondingly reduced time. 9. TESTS 9.1 Resistance Test (Routine) The overall resistance between the neutral connected terminal and the earthed terminal of the resistor shall be measured and corrected to a reference temperature of 100oC. The measured value of the resistance shall have a tolerance of not more than 5% of the designed value. 9.2 Applied Voltage Test (Routine) A sinusoidal alternating voltage having a value equivalent to 225% of the nominal voltage (Un/1,73) plus 2kV shall be applied for a period of 60 seconds between the terminals of the resistor and the tank and frame, all connected together and to earth.

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9.3 Temperature Rise Tests (Type) Tests shall be performed to verify that the requirements of Clauses 8.3.1, 8.3.2 and 8.3.3 have been met. A record of the maximum temperature rise of the top liquid shall be taken after the passage of the 10 second nominal short-time current. 9.4 Test Certificates Copies of test certificates giving all relevant details and results (including oscillograms) of the tests specified, shall be supplied to the purchaser prior to the despatch of the resistor from the manufacturer’s works. 10. QUALITY 10.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal internationally accepted industry expertise is expected throughout. 10.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 11. DRAWINGS The original drawings shall be prepared in such a manner that they comply fully with the requirements of SABS 011 and BS 308 in order that acceptable microfilm versions can be made from them. Where the supplier uses a CAD drawing system, he shall provide copies of the drawings on an AutoCAD compatible file. 12. LITERATURE Descriptive literature and drawings showing dimensions must accompany the offer. 13. SPARES AND SPECIAL TOOLS Tenderers shall quote for any spares, which are recommended, and any special tools necessary for replacing any part that may become defective. The tenderer must indicate what repair facilities are available in South Africa.

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14. INSTALLED USER BASE Tenderers must state how long the equipment offered has been in production, along with the names and addresses of at least two South African users who can be contacted for comment on the equipment.

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6,6 AND 11kV OIL COOLED OUTDOOR NEUTRAL EARTHING RESISTORS


REV NO.

DETAILS

AUTHOR


0

First Issue

BCF

October 1994

1

Put into Standard Word Format

KP

12 February 2001

2

General Editing

BCF

24 May 2002

of 2

REV – DRAFT 1 12 FEBRUARY 2001PEE STANDARD NO 106 – 6.6/11kV OIL COOLED OUTDOOR NER’s

FILED: F\DATA\STANDARDS\PEE_STD\STD 106 – NER’s (OIL COOLED)\STD 106 – Sched Guarantee.doc

NEUTRAL EARTHING RESISTOR FOR ..... SUBSTATION PEM SPECIFICATION NO ... SCHEDULE OF GENERAL PARTICULARS AND GUARANTEES

Required Offered

System Details: Nominal Voltage - Un (kV) Frequency (Hz)

22 50

xxxxx xxxxx

Details of N.E.R.: Nominal Voltage Nominal Short Time Current (A) Nominal Short Time (S) Nominal Resistance at 100�C (�)

Un/1,73 630 10 20

xxxxx xxxxx xxxxx xxxxx

Manufacturer Xxxxx

Type Designation Xxxxx

Material and Grade of Resistor Elements Xxxxx

Oil quantity (l) Xxxxx

Total mass of unit (kg) Xxxxx

Guaranteed Performance Data 1. Resistance (see clauses 8.4 and 9.2) - minimum value at 100�C ohms - maximum value at 100�C ohms - maximum value at 350�C ohms - tolerances applicable at guaranteed values % 2. Nominal voltage of resistor (rms) kV 3. Maximum continuous current on which temperature rise is based (see clause A 8.3.2 of PEM Standard No 106) 4. Short time current (for 10 seconds) on which temperature rise is based (see clause A 8.3.3 of PEM Standard No 106) 5. Temperature coefficient of resistor, above 100�C. �/�C 6. Specific heat of resistor material J/kg.K 7. Temperature range within which items 5 and 6 apply �C

Xxxxx Xxxxx Xxxxx Xxxxx Xxxxx Xxxxx Xxxxx Xxxxx Xxxxx Xxxxx

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REV – DRAFT 1 12 FEBRUARY 2001PEE STANDARD NO 106 – 6.6/11kV OIL COOLED OUTDOOR NER’s

FILED: F\DATA\STANDARDS\PEE_STD\STD 106 – NER’s (OIL COOLED)\STD 106 – Sched Guarantee.doc

NEUTRAL EARTHING RESISTOR FOR ..... SUBSTATION PEM SPECIFICATION NO ... SCHEDULE OF GENERAL PARTICULARS AND GUARANTEES

Required Offered

8. Temperature Rise of: 8.1 the top liquid - due to the passage of the maximum continuous current �C - due to the conditions specified in clause 8.3.3 of PEM Standard No 106 �C 8.2 the metallic resistor - due to the passage of the maximum continuous current �C - due to the conditions specified in clause 8.3.3 of PEM Standard No 106 �C

< 55 xxxxx < 60 < 350

BUSHINGS: Manufacturer

Xxxxx

Type designation Xxxxx

Nominal voltage (kV) Xxxxx

Nominal current (A) Xxxxx

Impulse withstand test voltage (1,2/50 micro-second full wave) (kVpk)

Xxxxx

Sixty second power frequency wet withstand test voltage (kV)rms

Xxxxx

Total creepage distance mm/kV 25

Protected creepage distance (90� rain) mm/kV Xxxxx

CURRENT TRANSFORMER: a) Accuracy Class to BS 3938 b) Accuracy Limit Factor c) Ratio d) Rated Burden (VA) e) Maximum Total Secondary Winding Resistance (�) f) Drawing No: of Magnetisation Curve

10P 10 500/1 15 xxxxx xxxxx

xxxxx xxxxx xxxxx xxxxx

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REV – DRAFT 1 4 JANUARY 2001PEE STANDARD NO: 110

132 kV and 66 kV OVERHEAD POWER LINES FILED-F:\DATA\STANDARDS\PEE_STD\STD 110 – OVERHEAD LINES (132 kV and 66 kV)\Std 110.doc




________________

132 kV and 66 kV OVERHEAD POWER LINES

____________________________

REV – DRAFT 1 4 JANUARY 2001

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BLANK PAGE

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TABLE OF CONTENTS

PAGE 1. SCOPE 6

2. REFERENCES 6 2.1 Standards 2.2 NMMM Standards and Codes of Practice 2.3 Statutory Requirements

3. SERVICE CONDITIONS 7

4. CONTRACTOR’S CODE OF CONDUCT IN RESPECT OF THE ENVIRONMENT 7


6. TECHNICAL REQUIREMENTS 8 6.1 General 6.2 Tower Foundations 6.3 Tower Earthing 6.3.1 Tests to be carried out prior to Excavation for Foundations 6.3.2 Earthing Materials 6.3.3 Tower Ground Resistance

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PAGE 6.3.4 Galvanic Corrosion 6.3.4.1 Shielding Wire Insulation 6.3.4.2 Substation Terminal Tower 6.3.5 Earthing Method 6.3.6 Earth Conductor Connections 6.3.7 Tests to be performed at Completion of Each Tower 6.4 Steel Structures 6.5 Hillside Extension Leg Requirements 6.6 Galvanising 6.7 Painting 6.8 Standardisation and Marking of Structural Components 6.9 Bolts and Nuts 6.10 Conductor 6.10.1 All Aluminium Alloy Conductor 6.10.2 Greasing 6.11 Shield Wire / OPGW Protection Angle 6.12 Line and Earth Conductor Fittings 6.13 Insulators 6.14 Anti-Climbing Devices, Tower Leg Steps

7. INTERFERENCE WITH PROPERTY 13

8. COMPLETION OF WORK 14

9. CONTRACT PRICING 14 9.1 Tender Prices

10. DRAWINGS 14 10.1 General

11. MARKING, LABELLING AND SIGNS 15 11.1 Labels 11.2 Signs

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PAGE 11.3 Tower Numbering 11.3.1 CFP Numbering 11.3.2 Serial Numbers

12. DATA SHEETS 16

13. TEST CERTIFICATES 16

14. LITERATURE / DOCUMENTATION 16


16. TECHNICAL BACK-UP 16



ANNEX 1 Painting of New Galvanised Steel Transmission Towers

ANNEX 2 Sealing of Bare Galvanised Steel Transmission Tower Structural Joints with Bitumen

during Erection

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1. SCOPE This Standard provides for the design, manufacture, erection and commissioning of 132 kV and 66 kV overhead power lines. 2. REFERENCES 2.1 Standards The overhead line and all components shall, unless otherwise specified, conform with the relevant Standards / Codes of Practice listed hereunder: - SABS 0160: 1989 : Code of Practice for General Procedures and Loadings to be adopted in

the design of buildings

SABS 044 : Welding

SABS 0100: 1992 : Structural Use of Concrete

SABS 0111 : Engineering Drawing – General Principles

SABS 0199: 1985 : The Design and Installation of an Earth Electrode

SABS 763: 1988 : Hot-Dip (galvanised) Zinc-Coatings (other than on continuously zinc-coated sheet and wire)

SABS CKS592: 1984 : Barbed Tape; Concertina

SABS 135 : Bolts and Nuts

SABS 0280 (NRS 041)

:

Code of Practice for Overhead Lines for Conditions Prevailing in South Africa (First Revision 1966)

IEC 493/1974 : Guide for Statistical Analysis of Ageing Tests Data

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BS 3242: 1970 : Aluminium Alloy Stranded Conductors for Overhead Power Transmission 2.2 NMMM Standards and Codes of Practice COP 10.1 : Common Rules

STD 134 : Composite String Insulators – 22 to 132 kV

STD 111 : Composite Overhead Ground Wire with Protective Optical Fibres

(OPGW) 2.3 Statutory Requirements All equipment, materials, methods of working and completed work offered against this Standard shall conform to the relevant requirements of the Occupational Health and Safety Act (Act 85 of 1993) as amended, and / or the Regulations framed under this Act. 3. SERVICE CONDITIONS The nominal system voltage is either 66 kV or 132 kV as stated in the Project Specification. The climatic, power system, insulation co-ordination and earthing detail shall be as outlined in PEE Code of Practice 10.1. 4. CONTRACTOR’S CODE OF CONDUCT IN RESPECT OF THE ENVIRONMENT Great care shall be taken during site and access preparation to ensure absolute minimum disturbance and damage to the vegetation. The following minimum steps shall be taken: -

The size of the work area shall be restricted to the minimum required for efficient and effective work;

A firm route shall be identified for access and clearly marked to avoid deviation there from.

Where vegetation is too big, it shall be chipped, but the soil, grass and smaller vegetation in the same area shall not be disturbed;

The work shall be properly planned in order to avoid unnecessary access to the place of

work;

No vegetation shall be removed other than the bare minimum required where foundation holes will be excavated;

Removed plant material shall be retained for later use in the re-vegetation and landscaping

of the areas;

All construction equipment shall be in good working order, especially with respect to oil, fuel, hydraulic and similar leaks;

No treatment of contaminated soils (e.g. bio-remediation) shall be allowed prior to obtaining

approval from the regional conservation authority;

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Excavated material shall be placed such as to have minimum impact on vegetation. Plan for worst case, i.e. heavy rainfall and run-off events or high winds;

Use separate storage for top and subsoil horizons, replacing them in the same order after

planting the tower feet where practically possible;

Spoil shall be removed from the site as soon as it is practically possible and disposed of at a registered waste disposal site;

All disturbed sites shall be re-vegetated and rehabilitated immediately after construction to

limit the exposure of the disturbed areas to wind and water erosion;

Protect exposed soils with coarse granular materials, mulches or straw where the above is not possible;

All litter shall be removed from the site at completion.

5. QUALITY 5.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 5.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 6. TECHNICAL REQUIREMENTS 6.1 General SABS 0160, SABS 0280, the Occupational Health and Safety Act (OHS Act) and PEE Code of Practice 10.1 (Clauses 1 and 8), all contain design parameters, which are in conflict with each other. For the purpose of this contract the most severe of the parameters referred to by these three documents shall apply. The Project Manager will not seek exemption from OHS Act in terms of SABS 0280 and the design shall meet all requirements of the Act. 6.2 Tower Foundations For quotation purposes, tower foundations shall be designed assuming the soil bearing pressure listed in the Project Specification.

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The successful tenderer must satisfy himself/herself regarding ground conditions at each tower position before finalising the design. He might require the service of a Geo-technical Engineer to carry out a soils investigation. Additional payment shall be allowed for soil conditions varying from the conditions stated in the Project Specification, providing that details of the tender design and the new design be made available to the Project Manager. Tenderers must submit all foundation and reinforcement details and concrete mix as part of the tender submission. All concrete, materials and workmanship shall be in accordance with SABS 0100-2: 1992 – Structural Use of Concrete. If part of the are where the line should be constructed is subject to periodic tidal flooding and / or has a high water table, the salinity of the water must be established to determine the concrete class and if protection of the reinforcement is required (refer to Clause 4.3.2). The portion of the tower legs to a height of not less than 300mm above finished ground level must be embedded in concrete. The top of the concrete shall have a slight taper (foundations shall be capped) for draining purposes. A UV resistant bitumen base sealer to be approved by the Employer shall seal off the tower leg entries into the concrete. Bond between the galvanised stub anchors and the concrete shall not solely be relied upon to transmit loads to the foundations. In addition, a mechanical bond shall be employed, viz. welding on a cleat or bar to the embedded end of the stub anchor. 6.3 Tower Earthing 6.3.1 Tests to be carried out prior to Excavation for Foundations A soil resistivity survey shall be carried out at each tower position before excavation for the foundations start. 6.3.2 Earthing Materials The earthing conductor shall be a 50mm x 6mm galvanised steel strip. Where earth rods will be used, these shall be designed and installed to SABS 0199. Stranded 70mm2 Cu conductor shall be used to connect earth rods together and to the tower. 6.3.3 Tower Ground Resistance The ground resistance of any tower shall be less than 10. 6.3.4 Galvanic Corrosion 6.3.4.1 Shielding Wire Insulation To prevent galvanic corrosion, the shield wires shall be insulated from the towers in the following scenarios: -

The last five towers on the substation end of the line including the termination tower;

Where the transmission line runs parallel to underground ferrous pipelines and / or railway tracks, inclusive of a distance of 800m from the point of deviation from the parallel run;

For 800m on either side of a railway track or a ferrous pipeline crossing.

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6.3.4.2 Substation Terminal Tower The two legs of the termination tower nearest to the substation shall be connected to the main substation earth mat using 70mm2 stranded copper conductor. Each tower leg shall have its own earth conductor. 6.3.5 Earthing Method 6.3.5.1 After foundations have been cast, a 50 x 6mm galvanised steel strap shall be taken down

each tower leg along the outside corner of each foundation. At the bottom of the foundation, the strap shall be wrapped around the foundation once and brought up the same route to the starting point.

6.3.5.2 Should the earth resistance obtained by 6.3.5.1 be higher than required, trench earths shall

be run out from two of the tower’s legs, which are diagonally across from each other. The depths and lengths shall depend on the soil resistivity survey to be done prior to excavating for the foundations.

6.3.5.3 Quotations (provisional) for 6.3.5.2 shall be based on a trench depth of 800mm and a length

of 15m each. 6.3.5.4 Further trench earths should be run from the remaining two legs, should the ground

resistance be too high following implementation of 6.3.5.3. 6.3.5.5 Should the soil resistivity survey display conditions more suitable for earth rods, suitable

earth rods could replace the trench earths in 6.3.5.2 and 6.3.5.4. Quotations should allow for 3 x 1,8m rods coupled to each other and driven to 500mm below natural ground level at two of the tower’s legs.

6.3.5.6 The tender price shall only allow for earthing in terms of 6.3.5.1. Should further earthing be

required, additional payment in accordance with the provisional amounts shall be allowed. 6.3.6 Earth Conductor Connections The earthing conductors shall be bolted to the tower legs. Where stranded copper is used, it shall be crimped in suitable bi-metal lugs and bolted to the tower legs. The copper conductor shall be CADWELDED to earth rods and to main substation earth mats where applicable. 6.3.7 Tests to be performed at Completion of Each Tower The following tests shall be done by contractors/sub-contractors with sufficient previous experience of similar tests: -

A ground resistance test in accordance with SABS 0199;

The step and touch voltages in accordance with IEEE 81.2: 1991. Tenderers shall quote in their tender submissions: -

The name of the sub-contractor who will carry out after-installation earthing tests;

The IEEE 81.2 method / instrumentation proposed to use for the step and touch voltage measurements.

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6.4 Steel Structures All steel used in the manufacture of the towers and tee-off arrangements shall conform to SABS 0162 Structural Use of Steel (all three sections). The grade of steel used shall be clearly indicated on the tender drawings. Rolled steel sections must have a minimum thickness of 5mm unless otherwise specified in the Project Specification. All steel used shall be free of blisters, scales, lamination and other defects. Tenderers’ attention is drawn to Clause 5.12.3, which would require a tower design capable of carrying suspended shielding conductor and OPGW. Overlapping steel sections shall be sealed off at bolt down positions by a UV resistant bitumen base sealer to be approved by the Employer. 6.5 Hillside Extension Leg Requirements Where towers on slopes need hillside extension legs, tenderers shall include prices for these with the tender. 6.6 Galvanising All the mild steel tower and line components including nuts, bolts and washers shall be hot-dip galvanised (heavy-duty requirements) in accordance with SABS 763. Galvanising shall be carried out in a professional way and sharp points where wrap-around wire has been used or as a result of dripping are unacceptable. The cost of re-galvanising any component, which does not comply with the requirements of the above Code of Practice shall be for the contractor’s account. 6.7 Painting Steel structures shall not be painted. 6.8 Standardisation and Marking of Structural Components All nominally identical structural members shall be interchangeable. All parts shall be carefully cut and holes accurately located so that when the members are in position, the holes will be truly opposite each other before being bolted up. Drifting of holes will not be allowed. No bolt hole shall be more than 2,0mm larger than the corresponding bolt diameter. Before leaving the manufacturer’s works, all members shall be stamped or marked in approved positions with distinguishing numbers and / or letters on approved drawings or material lists to be submitted by the successful tenderer. The erection marks shall be stamped before galvanising and shall be clearly legible after galvanising. 6.9 Bolts and Nuts Bolts and nuts shall be manufactured and supplied to SABS 135. All bolts must be supplied complete with washers, nuts and lock nuts.

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Bolts such as those for attaching the plates and brackets that support insulator strain sets shall have either self-locking nuts or lock nuts. In order to prevent theft of individual structural members, all nuts must be tack-welded to the bolt threads up to the height of the lowest cross-arm. Stainless steel welding rods must be used for this purpose. Welding positions shall be treated generously with cold galvanising. Final tightening of the nuts shall be done by torque wrench. 6.10 Conductor Unless otherwise specified in the Project Specification, phase conductors and earth wires shall be of all aluminium alloy conductor. Where OPGW is specified in the Project Specification, it will be supplied and installed to PEE Standard No 111. Tenderers must note that the conductor is to be used in a harsh coastal environment close to the sea. It is imperative that every effort be made to reduce corrosion in service to a minimum. 6.10.1 All Aluminium Alloy Conductor The conductor shall be in accordance with BS 3242. The conductor strands shall be drawn from solution treated (high temperature heat-soaked and quenched) redraw wire. The drawn conductor shall be artificially aged by annealing for several hours at a suitable low temperature to improve the corrosion resistance and increase conductivity as recommended by the suppliers of the redraw wire. 6.10.2 Greasing The conductors shall be greased using a process, which ensures that all layers are greased and all interstices filled. The grease shall have suitable properties of pseudoplasticity, thixotropy and syneresis. The grease shall be CABLE GUARD or approved equal. 6.11 Shield Wire / OPGW Protection Angle The earth wire / OPGW protection angle shall comply with SABS 003. 6.12 Line and Earth Conductor Fittings The tension and suspension insulator long rod units for the line conductors are to be secured to the cross-arms by means of galvanised tower shackles. All phase conductor insulator suspension attachment clamping arrangements shall be of the neoprene insert “Armour-Grip” suspension unit type with preformed aluminium alloy armour rods with “parrot bill” ends suitable for the line size as made by Preformed Line Products SA (Pty) Ltd or approved equal. The shielding wire(s) shall be suspended by means of suspension attachment units. Insulators shall be used where called for by Clause 5.3.4. All phase conductors and shielding wires (excluding OPGW) shall be made off at strainer and terminal towers by means of compression dead-end make-off assemblies as offered by ABB Feralin or CCL Bi-Metal Connector Manufacturers or approved equal.

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Composite long rod insulators shall not be fitted with arcing horns, except where called for by Clause 5.11.9. A sag adjuster shall be fitted between the insulator string and tower on all phase conductors at all strain and termination points. This shall be one of the Quadrant Plate Type as made by ABB Feralin or approved equal. Any shackles, pins or other line fittings, etc, not specifically mentioned shall be allowed for in the tender. Vibration dampers shall be of the solid polyvinyl chloride preformed spiral type and there shall be one fitted at both ends of each phase conductor span and earth wire span. The vibration dampers shall be as made by Preformed Line Products SA (Pty) Ltd or approved equal. To comply with the Electrical Machinery Regulations of OHS Act, Clause 20(e), the combination of Armour-Grip Suspension units and galvanised mild steel arcing horns shall be used. The arcing horns shall be double-point at suspension locations and single-point at strainer locations. Notwithstanding what is called for in PEE Standard No. 133, tongue-tongue end will be acceptable where arcing horns are installed. 6.13 Insulators 6.13.1 Phase Insulators Insulators shall be supplied in accordance with PEE Standard No. 133. 6.13.2 Earth Wire OPGW Insulators The purpose of the insulators is to prevent galvanic corrosion. The insulators shall be fitted with arcing horns. Tenderers shall submit information on both suspension and strain insulators including detail on insulation voltage, arcing horn gaps, fittings, material, etc. The successful tenderer shall submit samples for approval. 6.14 Anti-Climbing Devices, Tower Leg Steps All structures shall be fitted with barbed-tape anti-climbing devices at a height of not less than 3m from ground level. The barbed-tape shall be manufactured in accordance with SABS CKS592 of 1984. The barbed-tape shall be of the “concertina” coil form as offered by Cape Gate or approved equal. The coil diameter on the inside of the tower shall be 730mm while the outside coil shall be 980mm diameter. The barbed-tape and dovetail clips shall be heavy-duty galvanised to SABS 763. Tower leg steps shall be fitted up two opposite sides of the tower. The lowest steps shall be 3m above ground level. 7. INTERFERENCE WITH PROPERTY The tenderer shall conduct his work such that it will minimise interference with traffic and essential services and shall provide for and comply with any relevant ordinance. He shall liase with all relevant authorities before interfering with any traffic or other services.

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The contractor shall indemnify the Council against all actions and damage or proceedings, which may be brought or taken against the Council in respect of damage caused to any highway, road or street, or any person or property thereon, due to the conveyance, whether by ordinary or extraordinary traffic, by the contractor of any plant, materials, tools or tackle required for the works to, or from, the site during the period of contract. The contractor or his sub-contractor, representative, servants or workmen shall not in any way encroach on or interfere with private property, or property of the Council, or with any existing transmission lines, except with written approval. Where the power line servitude traverses private property, the contractor shall cause minimum possible disturbance to property and shall use his best endeavours to avoid friction with the property owners. Access routes will be pointed out to the contractor’s local agent and the contractor shall obtain access to the line route by means of these routes only. Funds required for the construction of additional access roads should be included in the tendered price. As each of the contract works is completed, the contractor shall, at his own expense, remove all rubbish, surplus excavated materials and debris, unused materials, temporary erections and plant. The contractor shall execute such works so as to ensure that the site of the contract works and the adjoining ground shall be left clear, all subject to approval. All litter and debris produced by the tenderer shall be collected and taken back to the construction camp for disposal at the end of each day’s work. 8. COMPLETION OF WORK As each part of the contract work is carried out, the City Electrical Engineer or his representative shall approve it and all work will be carried out to his satisfaction. 9. CONTRACT PRICING 9.1 Tender Prices In order that tenderers will all quote on the same basis if the price is not firm, tender prices are to be based on the applicable SEIFSA contract price adjustment formula and base prices for the month prior to tender closing date. All base prices for materials and labour shall be stated, together with the adjustment formula. The price quoted is to include all delivery charges and other costs or dues that may become payable whilst the equipment is in transit from the place of manufacture to its position at the site as defined. 10. DRAWINGS 10.1 General Drawings shall be done in AutoCAD Version 14 or later and shall be supplied in both software and hardware format. All drawings shall be to scale and fully detailed. All important dimensions shall be given. Drawings submitted for approval shall be in triplicate and the contractor shall supply any further copies upon request. The original drawings shall be prepared in such a manner that they comply fully with the requirements of SABS 0111 Part 1: Engineering Drawing – General Principles, in order that acceptable microfilm versions can be made from them.

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11. MARKING, LABELLING AND SIGNS 11.1 Labels All apparatus, where necessary / required, is to be clearly and indelibly labelled to ensure correct operation and safety both to the plant and to the operators. Labels not exposed to the weather shall be of engraved laminated Traffolyte or equal approved black material having white lettering or, in the case of danger notices, it shall have red lettering on a white background. Labels and diagram plates exposed to the weather shall be of stainless steel or equivalent with all information permanently applied by etching, engraving or stamping. All lettering shall be of ample size and clearly legible and all labels shall be attached by means of either screws, bolts and nuts or pop rivets. Labels and diagram plates should be offset from the apparatus to which they are fixed so that water may not collect between the two surfaces. 11.2 Signs Durable, heavy-duty, corrosion-resistant danger signs in English, Afrikaans and Xhosa are to be provided on each tower and gantry. These signs are to comply with the requirements of the Occupational Health and Safety Act, No 85 of 1993, as amended, and / or the Regulations framed there under. 11.3 Tower Numbering All towers and gantries are to be numbered by the contractor. Two types of numbers shall number towers, i.e. tower serial numbers and circuit fixing point (CFP) numbers. 11.3.1 CFP Numbering CFP numbering must be applied to all four legs, at approximately 2 metres above ground level, below the anti-climbing guard. Each circuit of the double line will have its own numbering systems. Each tower will therefore have two groups of 2 numbers, the numbers in each group being identical. Letters and numerals must be 80mm in height. After thorough de-greasing of the number positions, a background colour of Canary Yellow shall be painted using approved enamel paint to SABS Specification 630. The paint thickness shall be to the paint manufacturer’s specification. Letters and numerals shall be done in black enamel paint complying with SABS Specification 630. Characters shall be straight and evenly spaced. The paint thickness shall be to the paint manufacturer’s specification. Each number could consist of a maximum of 25 characters. The average number of characters per CFP number shall be 16. 11.3.2 Serial Numbers Serial numbers shall be supplied complete to the contractor who shall install the same at a height of approximately 1.8 metres above ground level.

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12. DATA SHEETS The contractor will be required to complete data sheets identical to the one included in Annex F in respect of each tower. Blank data sheets will be provided to the contractor. 13. TEST CERTIFICATES Two certified copies of test certificates must be submitted with the tender to show that the towers offered have passed tower tests in accordance with the relevant South African, IEC and British Standards specified and to verify that the design is satisfactory for the specified duty. A “Letter of Compliance” shall be obtained from the galvanising firm(s) stating that all hot-dip zinc coatings comply with the requirements of SABS 763 (Heavy-Duty). Two certified copies of test certificates shall be submitted to the City Electrical Engineer for each length of conductor, as manufactured. Any tests proving that the conductor parameters fall outside the specified limits shall result in rejection of the whole manufactured length. A “Letter of Compliance” shall be obtained from the AAAC conductor manufacturer(s) stating that all conductors supplied has been greased in accordance with Clause 4.10.2 of this Standard. The costs of all tests, certificates and “Letters of Compliance” required must be included in the tendered price and detailed in the tenderer’s covering letter. 14. LITERATURE / DOCUMENTATION The tender offer must be accompanied by descriptive literature and drawings showing dimensions. 15. SPARES AND SPECIAL TOOLS Tenderers are to quote for any spares and special tools, which are considered necessary for maintaining the equipment in service. If bolts or nuts are so placed as to be inaccessible with ordinary spanners, suitable special spanners shall be supplied. 16. TECHNICAL BACK-UP Details of the technical back-up / repair facilities available in South Africa are to be provided. 17. INSTALLED USER BASE Tenderers must state how long each type of tower offered has been in service, along with the names and addresses of at least two South African users who can be contacted for comment on the performance.

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REV NO.

DETAILS

AUTHOR


of 9

REV – DRAFT 6 15 MAY 2001PEE STANDARD NO: 113

INDOOR CONTROL PANELS FILED-F:\DATA\STANDARDS\PEE_STD\STD 113 – INDOOR CONTROL PANELS\Std 113.doc




________________

INDOOR CONTROL PANELS

(66 kV and 132 kV)

____________________________

REV – DRAFT 6 15 MAY 2001

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INDOOR CONTROL PANELS (66 kV and 132 kV)

TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5 2.1 Standards

3. REQUIREMENTS 5 3.1 Particulars of the Distribution System 3.2 Auxiliary and Trip Supplies 3.3 Construction of Panel 3.4 General Requirements 3.5 Instruments 3.6 Wiring


5. DRAWINGS AND INSTRUCTION MANUALS 8 5.1 Supplied by all Tenderers 5.2 Documents supplied by Successful Tenderer

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1. SCOPE This Standard provides for the design, manufacture, works testing and supply and delivery of indoor control panels for 66 kV and 132 kV equipment. The control panels shall be complete with relays as called for in the particular Contract Specification. 2. REFERENCES 2.1 Standards The indoor control panels shall, unless otherwise specified, be manufactured and tested in accordance with the relevant requirements of the latest versions of the Standards listed hereunder: - SABS 0111 : Part 1: Engineering Drawing – General Principles


SABS 1091 : National Colour Standards for Paint

PEE Std No: 100 : Protection and Auxiliary Relays

PEE Std No: 101 : SCADA Interface Requirements 3. REQUIREMENTS 3.1 Particulars of the Distribution System 3.1.1 The nominal voltage of the system is 132 kV and 66 kV, 3 phase, 50 Hz and the source

neutral points are solidly earthed. 3.1.2 The phase sequence is non-standard i.e. R-B-Y-R. Care must be taken to ensure that any

meter and relay circuits are correctly connected for this reverse rotation.

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3.2 Auxiliary and Trip Supplies 3.2.1 The equipment offered shall be suitable for use at the following voltage levels: -

Tripping circuit - 110 V DC Indicating lights and alarms - 110 V DC Panel interior lighting - 230 V single phase AC

3.3 Construction of Panel 3.3.1 The control panels shall be constructed of mild steel and shall be of the free standing floor-

mounted type suitable for indoor use. The panels are to be assembled together to form a row.

3.3.2 The panels shall be of robust construction, each of approximate dimensions 2 000mm high x

610mm deep and shall be provided with a hinged rear door access. Designs incorporating hinged front door access will be to the approval of the City Electrical Engineer.

3.3.3 The primed exterior surface of the control panel shall be covered by one under coat and

finished with two coats of polyurethane acrylic gloss enamel, Colour No. G29, to SABS 1091 Light Grey. The dry film thickness of each coat shall be not less than 25 micro-metres.

3.3.4 The interior surface of the control panel shall receive a primed under coat and two finishing

coats of paint applied to the thoroughly cleaned metal surface. The final coat on the interior surface shall be white. Any interior backing boards shall also be finished in white.

3.3.5 The panel shall be adequately ventilated to prevent over-heating of the internal equipment. 3.3.6 Suitable gland-plates shall be provided in all panels for terminating multi-core cables. 3.3.7 The panels shall be equipped with a copper earth bar with a minimum cross-sectional are of

150mm2 and of sufficient length to allow for the termination of all incoming and outgoing earth conductors.

3.4 General Requirements 3.4.1 The control panels are to be provided with relays as listed in the Schedule of Particulars and

Guarantees, all in accordance with PEE Standard No. 100. 3.4.2 Engraved labels securely fixed by screws or rivets are to be provided to show the function of

each relay, MCB or link. 3.4.3 All relays are to be flush-mounted on panel fronts suitably stiffened to reduce vibration to a

minimum. 3.4.4 Miniature circuit breakers of appropriate ratings are to be provided on the back of the relay

panels in order to provide “sub-circuit protection” to the various circuits. Such MCB’s shall be fitted with an “OFF” alarm contact wired in accordance with the relevant clauses of PEE Standard 101.

3.4.5 Trip circuits to equipment external to the panel shall be wired via withdrawable links mounted

externally on the front of the control panel.

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3.4.6 All DC circuits shall be protected by MCB’s / fuses of appropriate rating, fitted in the positive leg, with withdrawable links fitted in the negative leg.

3.4.7 High intensity LED’s for appropriate indication shall be mounted on the front of the panel and

labelled. The LED’s shall be coloured as indicated below: -

Red - Closed Green - Open White - Healthy Trips Amber - Spring Discharged

3.5 Instruments 3.5.1 Indicating ammeters shall have a 144mm x 144mm faceplate and shall comply with the

relevant parts of IEC 51 for instruments. The ammeter shall be of the moving-iron spring-controlled type having a minimum scale length of 150mm.

3.5.2 Ammeter scale plates marked with the current transformer ratio shall be provided to suit all of

the current transformer ratios specified. It shall be possible to replace the scale plate without removing the instrument from the switchboard.

3.5.3 Ammeter scales shall allow for 120% of the primary rating of the current transformer. All

current operated instruments shall be protected against over-current up to 120% of normal value or high current surges up to the fault rating of the circuit breaker. The current transformer ratio shall be clearly marked on the face of the ammeter.

3.5.4 Ammeters associated with multi-tap current transformers shall be provided with a scale plate

for each ratio. The switchgear panel shall be supplied with the scale specified in the Schedule of Particulars and Guarantees fitted and, unless the scales are reversible, the other scale plates shall be placed in a transparent envelope permanently fixed behind the relay chamber door.

3.5.5 When specified, voltmeter scales shall have an indicating range of 80% to 120% of normal

system voltage. Where voltmeters that have a normal range from zero to 120% are required, this will be specified.

3.6 Wiring 3.6.1 All relays and associated equipment shall be conveniently housed on the panel and all

internal wiring shall be laced or run in wiring channels. 3.6.2 The small wiring of the control panel shall be in 250 V grade PVC insulated wire of not less

than 2,5mm2 stranded copper conductor to SABS 150. 3.6.3 Numbered ferrules corresponding with the wiring diagrams are to be provided at each end of

each wire. Unless otherwise approved, the ferrules shall be white with black figures. 3.6.4 Wires are to be terminated with compression lugs suitable for the type of terminal used. Not

more than two wires shall be connected to any one terminal. 3.6.5 The terminals for current transformer circuits shall be of the Klippon type, ST5 or equivalent.

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3.6.6 Inter-panel wiring, where applicable, shall not interfere with the front and rear panel access. 4. QUALITY 4.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 4.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 5. DRAWINGS AND INSTRUCTION MANUALS 5.1 Supplied by all Tenderers 5.1.1 Tenders must be accompanied by descriptive literature providing full technical details of the

equipment to be supplied. Drawings indicating the overall dimensions of the control panels shall be supplied.

5.1.2 Tenderers must submit with their tender, the names of installations in the Republic of South

Africa where the equipment offered is in service, together with the name of the contact person.

5.2 Documents supplied by Successful Tenderer 5.2.1 The successful tenderer will be required to submit drawings in duplicate for approval before

manufacture is commenced. In any event, the drawings must be supplied within two months of the date of receipt of Council’s Letter of Acceptance.

The following drawings are required: - 5.2.2.1 General Arrangement; 5.2.2.2 Schematics

5.2.2 The successful tenderer will be required to supply, before despatch of equipment, three

copies of “as built” drawings and manufacturer’s pamphlets for all relays. 5.2.3 The original drawings shall be prepared in such a manner that they comply fully with the

requirements of SABS 0111 and BS 308 in order that acceptable microfilm versions can be made.

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REV NO.

DETAILS

AUTHOR


4

Change on page 3 in 3.4.1 – The control panels are to be provided with relays as listed in the Schedule of Particulars and Guarantees, all in accordance with PEE Standard 100

MTO

3 May 1996

5

Clause 3.3.4 – Removed requirement for anti-condensation paint finish. Clause 4 amended to include subsection on General Quality Requirements

MTO/ BCF

12 July 2000

6

Minor textual corrections Clause 3.5.1 amended to call for 144mm x 144mm face plates

MTO/ BCF

15 May 2001

Rev – Draft 4 3 May 1996PEE STANDARD NO 113 : INDOOR CONTROL PANELS

FILED : F:\DATA\STANDARDS\PEE_STD\04 SECT 3 – SUBSTATIONS\STD 04-113 INDOOR CONTROL PANELS\SCHEDULE-GUARANTEES

- D1 -

CONTRACT TITLE SCHEDULE OF GENERAL PARTICULARS AND GUARANTEES SPECIFICATION FOR CONTRACT NO. PEE ………. ......................(DATE)

1 2 3 4

Item Description Required Offered

General Size: a) Overall height b) Overall width c) Overall depth Paint Finish: a) Outside b) Inside Terminal Blocks: CT Circuits: a) Manufacturer b) Type c) Size d) Maximum voltage V e) Maximum continuous current rating A f) Withstand voltage kV Others: a) Manufacturer b) Type c) Size d) Maximum voltage V e) Maximum continuous current rating A f) Withstand voltage kV Control and Indication Equipment: Supervisory ON/OFF switch Ammeter Ammeter selector switch Circuit breaker trip/close switches Trip circuit healthy lamp and push buttons Are lifting eyes provident? Size of copper earth bar.

2 000 mm 610 mm 610 mm

Light Grey White

xxxxx Klippon ST5

Yes Yes Yes Yes

Yes

150mm²

NAME OF TENDERER: ............................................................................................... SIGNATURE: ............................................................................ DATE: ....................

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OUTDOOR TYPE SURGE ARRESTERS FILED-F:\DATA\STANDARDS\PEE_STD\STD 114 – OUTDOOR TYPE SURGE ARRESTERS\Std 114.doc




________________

OUTDOOR TYPE SURGE ARRESTERS

____________________________


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TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. APPLICABLE REFERENCES 5

3. SERVICE CONDITIONS 5 3.1 Particulars of the Distribution System 3.2 Connection to System 3.3 Basic Insulation Level

4. REQUIREMENTS 5 4.1 Arrester Voltage Rating 4.2 Deviations from Normal Service Conditions 4.3 Housing 4.4 Mounting 4.5 Metal Finish 4.6 Cantilever Strength

5. TESTS AND TEST RESULTS 6

6. DRAWINGS 6

7. QUALITY 6 7.1 General

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7.2 Quality Assurance Provisions


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1. SCOPE This Standard provides for the design, manufacture and testing of outdoor type metal-oxide surge arresters without gaps. 2. APPLICABLE STANDARDS Except where otherwise specified, all equipment supplied in terms of this tender shall comply with the relevant requirements of SABS IEC 99-4: 1991. 3. SERVICE CONDITIONS 3.1 Particulars of the Distribution System The surge arrester will be installed on a 3 phase, 50 Hz system with an effectively earthed neutral. 3.2 Connection to System The surge arresters will be connected phase to earth. 3.3 Basic Insulation Level The insulation level of the equipment to be protected will be as follows: - Nominal system voltage: 66 kV 132 kV Lightning impulse withstand voltage: 350 kV 550 kV 4. REQUIREMENTS 4.1 Arrester Voltage Rating The arrester voltage rating shall be 60 kV or 120 kV for systems having nominal voltages of 66 kV or 132 kV respectively.

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4.2 Deviations from Normal Service Conditions The equipment will be subject to heavy coastal salt pollution. 4.3 Housing The surge arrester blocks shall be contained in a porcelain housing. The minimum specific creepage distance between phase and earth shall be 25mm per kV of Um. 4.4 Mounting Surge arresters shall be suitable for pedestal mounting. 4.5 Metal Finish All external ferrous parts associated with the surge arresters shall be hot-dip galvanised to SABS 736. 4.6 Cantilever Strength The surge arresters must withstand a horizontal force of 1 250 N applied at the line terminal. 5. TEST AND TEST RESULTS 5.1 Certified copies of test certificates, showing results of type tests (design tests) performed in

accordance with SABS IEC 99-4: 1991 (Section 7) on equipment similar to that being offered are to be included with the tender.

5.2 Duplicate copies of test certificates, showing results of routine tests performed in accordance

with SABS IEC 99-4: 1991 (Section 8) are to be supplied prior to delivery of the equipment. 6. DRAWINGS The tenderer must supply within four weeks, copies in triplicate of fully dimensioned drawings of the surge arresters, which shall include detail of the mounting and line termination arrangements. The original drawings shall be prepared in such a manner that they comply fully with the requirements of SABS 0111 and BS 308 in order that an acceptable microfilm version can be made therefrom. 7. QUALITY 7.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout.

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7.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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REV NO.

DETAILS

AUTHOR


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OUTDOOR DISCONNECTORS (66kV and 132kV) FILED-F:\DATA\STANDARDS\PEE_STD\STD 122 – OUTDOOR DISCONNECTORS (66kV and 132kV)\Std 122.doc




________________

OUTDOOR DISCONNECTORS

66kV and 132kV

____________________________

REV – DRAFT 2 10 MAY 2001

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OUTDOOR DISCONNECTORS 66kV and 132kV

TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5

3. VARIATIONS FROM AND ADDITIONS TO NRS 031 5 3.1 Phase Clearances 3.2 Particulars of the Distribution System 3.3 Interlocks 3.4 Conductor Attachment Clamps 3.5 Spares and Special Tools 3.6 Marking / Labelling / Documentation 3.7 Drawings 3.8 Tests and Test Certificates 3.9 Instruction Maintenance Manuals 3.10 Greasing of Main Contacts 3.11 Auxiliary Switches for Buszone CT Selection


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1. SCOPE This Standard provides for the design, manufacture, testing, supply and delivery of 66kV and 132kV outdoor disconnectors and earthing switches. 2. REFERENCES The disconnectors shall be manufactured and tested in accordance with the relevant requirements of the standards listed hereunder: - NRS 031: 1993: Alternating Current Disconnectors and Earthing Switches SABS 0111: Part 1: Engineering Drawing – General Principles SABS ISO 9000: Quality Systems 3. VARIATIONS FROM AND ADDITIONS TO NRS 031 3.1 Phase Clearances The centre to centre phase clearances shall be as follows: - 66kV 2 000mm 132kV 2 500mm 3.2 Particulars of the Distribution System 3.2.1 The disconnectors will be installed on a 3 phase basis, 50 Hz system with an effectively

earthed neutral. 3.2.2 The phase sequence, being R-B-Y-R, is non-standard.

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3.3 Interlocks Fortress interlocks are required for safety operation of the substation. All locks shall be provided with stainless steel protective caps and “O” ring seals. The principle features of the interlocks shall be: -

To disable the operation (open or close) of the main contacts of the disconnectors on load;

To disable the operation of the earthing switches when the main contact is closed. One spare set of keys shall be provided in a suitable box. The box shall have a front glass window and shall be fitted with a lock. 3.4 Conductor Attachment Clamps Preference will be given to palm type clamps. 3.5 Spares and Special Tools Tenderers shall quote separately for any spares that are recommended and any special tools required for the installation and maintenance of the equipment. 3.6 Marking / Labelling / Documentation The language used for labels, drawings, certificates and manuals, shall be in English. 3.7 Drawings The original drawings shall be prepared in such a manner that they comply fully with the requirements of SABS 0111 and BS 308 in order that acceptable microfilm versions can be made from them. Drawings in CAD format are preferred. Where CAD drawings are available, the successful tenderer shall submit drawings in electronic form when called upon to do so. 3.8 Tests and Test Certificates Certified copies of test certificates, showing the results of type tests, shall be included with the tender. The results of routine tests shall be submitted for approval prior to delivery of the equipment. 3.9 Instruction / Maintenance Manuals Triplicate copies of installation, operation and maintenance manuals for the equipment are to be submitted before delivery. 3.10 Greasing of Main Contacts Main contacts of both disconnectors and earthing switches shall be greased using CONTREP or an approved equivalent. 3.11 Auxiliary Switches for Buszone CT Selection When type G and N contacts as per IEC 947-3 are specified, in addition to the requirement for no overlap, there must be a margin between opening of the G contact and closing of the N contact of at least 20% of main contact travel.

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The successful tenderer must supply test results for the auxiliary switches to prove compliance with this requirement. 4. QUALITY 4.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 4.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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REV NO.

DETAILS

AUTHOR


0

New Draft

PG

5 November 1999

1

Put into Standard Word Format

KP

8 January 2001

2

Minor textual corrections and added in Clause 3.11

MTO / BCF

10 May 2001

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SUPPORT STRUCTURES (HV YARDS) FILED-F:\DATA\STANDARDS\PEE_STD\STD 123 – SUPPORT STRUCTURES (HV YARDS)\Std 123.doc




________________

SUPPORT STRUCTURES IN HIGH VOLTAGE

OUTDOOR SUBSTATION YARDS DESIGN, CONSTRUCTION & INSTALLATION

____________________________


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SUPPORT STRUCTURES IN HV OUTDOOR SUBSTATION YARDS

DESIGN, CONSTRUCTION & INSTALLATION

TABLE OF CONTENTS

PAGE 1. SCOPE 4

2. REFERENCES 4

3. STRUCTURAL DESIGN 5

4. CLEARANCES 6

5. MANUFACTURE AND ERECTION OF STRUCTURES 6

6. HEIGHT OF STRUCTURES 6



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1. SCOPE This Standard provides for the design, construction and erection of structures to support the busbars, isolating switches, earthing switches, instrument transformers, surge diverters, etc. to be erected in medium and high voltage outdoor substation yards. 2. REFERENCES PEE Standard No. 120 : Atmospheric and Environmental Conditions

PEE Standard No. 121 : Safety Factors and Other Principles applicable to the Mechanical

Strength Calculations of Outdoor Electrical Equipment, their Support Structures and Foundations

SABS 0120 : Corrosion Protection of Structural Steelwork

SABS 0160 : The General Procedures and Loadings to be adopted in the design of Buildings

SABS 0280 : Code of Practice for Overhead Power Lines for conditions prevailing in South Africa

SABS 1431 : Weldable Structural Steels

BS 5950 (parts 1 – 9) : Structural use of Steelwork in Building (parts as applicable to the design in question e.g. specification for materials, rolled and welded sections, design of cold formed thin gauge sections etc.)

BS 7354 : Code of Practice for the Design of High Voltage Open Terminal Stations

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BS 7613 : Specification for Hot Rolled Quenched and Tempered Weldable Structural Steel Plates

BS 7668 : Specification for Weldable Structural Steels. Hot finished structural hollow sections in weather resistant steels

BS EN 10029 : Specification for tolerances on dimensions, shape and mass for hot rolled steel plates 3mm thick or above

BS EN 10113 (parts 1-3) : Hot-rolled products in Weldable Fine Grain Structural Steel

BS EN 10155 : Structural steels with Improved Atmospheric Corrosion Resistance Technical Delivery Conditions

BS EN 10210 – 1 : Technical Delivery Requirements 3. STRUCTURAL DESIGN The atmospheric and environmental conditions outlined in PEE Code of Practice 10.1 Section 2, shall be considered. The safety factors and other principles outlined by PEE Code of Practice 10.1 Section 9, shall apply. Drawings of supporting structures shall clearly indicate the maximum forces and turning over moments (in all directions) for which they have been designed, together with the safety factors used and other assumptions made. All structural steel shall be mild steel to the requirements of BS 7613, BS 7668, BS EN 10029, BS EN 10113 Parts 1 to 3, BS EN 10155 and BS 10210-1 as applicable. The design of the structures should preferably allow for the use of easily available standard steel sections. The height of structures shall be such that all busbars can be perfectly horizontally mounted. All structural steel shall be in accordance with the relevant requirements of the reference documents as previously listed. Due to the temperature variations experienced by a structure that is erected outdoors, it is necessary that due care be taken during the design of the structure to ensure that expansion and contraction will not damage either the structure or its foundations. Provision is to be made for the installation of the electrical equipment that is to be mounted on the structure, taking due care to ensure that all features required for the installation of the said equipment are available. This has specific reference to the location of any holes that are to be provided or brackets that are to be mounted on the structure. Where sections of the structure are to be bolted together, specific torque requirements are to be specified for the tightening of these bolts. Cognisance is to be taken of the fact that wind causes vibration of steel structures, which vibration could loosen bolts that are not correctly tightened. All items required for the attaching of steel sections to one another e.g. bolts, nuts and washers are to be specified as well as the sequence in which they are to be used to connect the sections of steel.

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Structures shall be designed and the associated drawings signed by an ECSA registered professional civil or structural engineer with at least 2 year’s relevant experience after registration as a professional engineer. 4. CLEARANCES The support structures, complete with busbars and droppers, shall be designed such that under the wide range of atmospheric and environmental conditions covered by the Code of Practice 10.1 Section 2 and all conditions of loading as covered by the Code of Practice 10.1 Section 9, the electrical and safety clearances shall be equal to or greater than those specified below. The temperature variation of busbars (tubular and flexible conductor type), shall be considered –5oC to 75oC. Electrical and safety clearances shall be in accordance with the Code of Practice 10.1 Section 5. 5. MANUFACTURE AND ERECTION OF STRUCTURES All structural steelwork shall be hot-dip galvanised. Care shall be taken that the galvanised surfaces are not damaged during storage, transport or erection. All members of the structure shall be manufactured with care. Jigs shall be used for the cutting and drilling of the material such that when erected on site, all members shall fit neatly together and all holes shall be truly aligned. No cutting, drilling, punching, etc. of galvanised steel will be permitted. Bolt hole clearances shall not exceed 2mm for bolts of up to M15 and shall not exceed 3mm for larger sizes. Holes shall not be elongated unless otherwise approved. Each fabricated member shall be stamped (before galvanising) with an erection mark corresponding to the markings shown on the final approved structural arrangement drawings. The design of the structure and the procedure for erection shall ensure that no members are strained or damaged during erection of the structures or the erection and tensioning of conductors. 6. HEIGHT OF STRUCTURES To be such that busbars are 100% horizontal. 7. QUALITY 7.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout.

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7.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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REV NO.

DETAILS

AUTHOR


0

New Draft

PG

5 November 1999

1

PG

7 January 2002

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REV – DRAFT 2 8 AUGUST 2001PEE CODE OF PRACTICE NO: 124

TUBULAR ALUMINIUM BUSBARS AND CLAMPS FILED-F:\DATA\STANDARDS\PEE_STD\STD 124 – TUBULAR ALUMINIUM BUSBARS\Std 124.doc




________________

TUBULAR ALUMINIUM BUSBARS AND

CLAMPS

____________________________

REV – DRAFT 2 8 AUGUST 2001

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TUBULAR ALUMINIUM BUSBARS AND CLAMPS

TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5

3. MATERIAL 5 3.1 Busbars 3.2 Clamps / Connections

4. CURRENT RATING 6

5. BUSBAR MANUFACTURING 6

6. CLAMPS AND CONNECTORS 6

7. LOADING DETAIL AND FACTORS OF SAFETY 6

8. SELECTION OF BUSBARS 6 8.1 Mechanical Strength to Suit the Loading Conditions of Either 8.2 Current Carrying Capacity, both Normal and Short-Time

9. MAXIMUM LENGTHS 7

10. CORROSION 7

11. INSTALLATION 7 11.1 Application Principles

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PAGE 11.2 Dissimilar Metals 11.3 Welding 11.4 Jointing Compound 11.5 Joints – Compliance with ESI Standard 41 – 11 11.6 Bending



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1. SCOPE This Standard provides for the design, manufacture, testing, supply and delivery of tubular aluminium busbars and associated clamps in accordance with the specification below. Where called for in the Project Specification, the busbars shall also be installed in accordance with this specification. 2. REFERENCES ISO 6362 Parts 1 to 5 : Wrought Aluminium and Aluminium Alloy extruded rods / bars,

tubes and profiles

AWS D1.2 : Welded Fabrication Code (AFSA Supplement covering locally available alloys and weld wires)

ESI Standard 41 – 11 (Feb ’82) : Tubular Aluminium Busbars, Connections and Terminal Fittings for 132kV Outdoor Substations

PEE COP 10.1 Section 9 : Safety Factors and other Principles applicable to the Mechanical Strength Calculations of Outdoor Electrical Equipment, their Support Structures and Foundations

HV CONNECTOR CLAMPS manufactured by McWade Productions (Pty) Ltd. 3. MATERIAL 3.1 Busbars Busbars shall be of tubular construction using aluminium 1350. Should this alloy prove to be unpractical due to its mechanical limitations, alloy 6063–T6 shall be used. Where the mechanical strength properties of this alloy are insufficient due to long lengths or other similar factors, alloy 6061–T6 shall be used.

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3.2 Clamps / Connections Clamps shall be of the same aluminium alloy as busbars. Clamps shall be supplied pre-grease specification. All 132kV primary equipment terminals shall conform to ESI Standard 41-11, i.e. 4 x M16 fixings on a 127 PCD. For voltage 66kV and below the terminals shall be 4 x M12 fixings on a 76 PCD. 4. CURRENT RATING The current rating of the busbars and connections / clamps shall be suitable for the maximum current and fault current ratings specified in the Project Specification. The conducting area of bolted clamps shall be considered as 2% of the total contact surface and with this taken into account, the current density of the connection shall not be more than that in the busbar and clamp. 5. BUSBAR MANUFACTURING Busbars shall be manufactured to ISO 6362. To minimise corona, surfaces shall be free from weld spatter, marks and indentations. Contact faces shall be smooth, flat and free from burrs, indentations, weld spatter, etc. Contact surfaces shall be protected during transit and storage. 6. CLAMPS AND CONNECTORS All clamps and connectors shall have a current carrying capacity and short circuit withstand capability of not less than the conductors joined thereby. All clamps shall be specifically designed for the particular application to avoid deformation of the conductors. Rigid busbars shall be clamped at one end only and have flexible connections at the other end to allow for expansion and contraction. Strain clamps for use with insulator strings shall be made of certified iron and steel and the minimum ultimate strength shall suit the loading details and factors of safety specified in PEE CoP 10.1. 7. LOADING DETAIL AND FACTORS OF SAFETY The loading details and factors of safety for all busbars and connections shall be at least that specified in PEE Standard Number 121. 8. SELECTION OF BUSBARS Busbars shall be selected on the basis of the following.

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8.1 Mechanical Strength to suit the Loading Conditions of either: -

The maximum span length as stated in the Project Specification, or

The maximum span according to the HV yard layout, where the contractor is responsible for the design of the substation.

All loading factors outlined in PEE Standard Number 121 shall be considered. 8.2 Current Carrying Capacity, both Normal and Short Time 9. MAXIMUM LENGTHS The two limiting factors for tube lengths are: -

Wind vibration;

Stress in the tube material. Damping methods for wind vibration will be allowed but the contractor shall take both these factors into account to determine maximum lengths for tubes. 10. CORROSION All ferrous parts shall be hot-dip galvanised. 11. INSTALLATION Where installation is called for in the Project Specification, the assembly instructions (page 2) in HV Connector Clamps (McWade Productions (Pty) Ltd), supported by the following requirements, shall be followed: - 11.1 Application Principles The application principles in paragraph 7 ESI Standard 41-11 shall be adhered to. 11.2 Dissimilar Metals Dissimilar metals shall not be used in contact with each other. Bi-metal connectors / connections shall be used in such cases. 11.3 Welding Busbars shall not be weld unless the written approval of the Engineer has been obtained in which case welding shall be done in accordance with AWS D1.2. The weld wire shall be 4043. 11.4 Jointing Compound A jointing compound such as the DSC80 / DSC100 dielectric silicone compound (available from Contact Engineering in Boksburg), shall be used on clamped joints.

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11.5 Joints – Compliance with ESI Standard 41-11 Jointing shall be carried out to ESI 41-11 (Paragraph 10, pages 15, 16 and 17), except that the torque wrench settings shall be replaced by the recommended values of the clamp suppliers. The testing of joints (paragraph 10.3) is of particular relevance. Although the use of a torque wrench is only recommended by ESI 41-11, the use shall be compulsory for this project. 11.6 Bending Bent tubes should be avoided. Where this is not practical, the Engineer’s permission in writing shall be obtained and the bends shall be achieved by cold bending. 12. QUALITY 12.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 12.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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REV NO.

DETAILS

AUTHOR


0

New Draft

PG

5 November 1999

1

Amended Draft

PG

8 January 2001

2

Amended Draft

PG

8 August 2001

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EARTHING OF MAJOR SUBSTATIONS DONE BY TURN-KEY FILED-F:\DATA\STANDARDS\PEE_STD\STD 125 – MAJOR SUBSTATION EARTHING (TURN-KEY)\Std 125.doc




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EARTHING OF MAJOR SUBSTATIONS DONE

BY TURN-KEY

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EARTHING OF MAJOR SUBSTATIONS DONE BY TURN-KEY

TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5

3. EARTHING GRID DESIGN PROCEDURE 5

4. SOIL SURVEY AND CALCULATIONS 6

5. DESIGN CRITERIA 6 5.1 Depth of Earthing Grid 5.2 Resistance of the Earthing Grid 5.3 Overhead Line Earth Wires 5.4 Type and Size of Main Earth Conductor 5.5 Fault Duration

6. GENERAL CONSTRUCTION DETAIL 6

7. EARTHING OF OUTDOOR TYPE EQUIPMENT 6 7.1 Apparatus to be connected to the Earthing Grid 7.2 Conductor Type for connecting apparatus to Earthing Grid 7.3 Conductor Size necessary for connecting apparatus to the Earthing Grid 7.4 Connections 7.5 Portable Earths

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PAGE 7.6 Inspection by the Engineer 7.7 Perimeter Fence

8. EARTHING OF INDOOR TYPE EQUIPMENT 7 8.1 Apparatus to be connected to the Earthing Grid 8.2 Conductor Type and Size for the Main Indoor Loop 8.3 Conductor Size necessary for connecting apparatus to the Earthing Grid

9. EARTHING OF LIGHTNING MASTS AND ARRESTORS 8

10. EARTH RODS 8

11. TESTS 8

12. INFORMATION TO BE SUPPLIED BY THE CONTRACTOR 8 12.1 Within Two Months after Appointment 12.2 Within Two Weeks after Testing



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1. SCOPE This Standard provides for the design, supply, installation, connection, jointing and testing of the substation earthing system in turn-key projects. The quotation shall allow for all necessary excavation, laying, jointing and reinstatement. The contractor shall supply all major and minor equipment and material. 2. REFERENCES The design shall be done in accordance with the following Standard: - IEE Std 80 – 1986 : Guide for Safety in AC Substation Grounding Implementation shall be done in accordance with the following Standard: - British Standard Code of Practice CP 1013 : 1965 The following Standards are only of relevance where referred to in the text below: - BS 7354 P 1990 : CP for Design of High-Voltage Open-Terminal Stations SABS 1063 : Earth Rods, Couplers and Clamps SABS 0199 : The Design and Installation SABS 806 : Grade A Tough Pitch Copper 3. EARTHING GRID DESIGN PROCEDURE The Design Procedure Block Diagram (Figure 26, page 111) of IEEE Std 80 shall be used to design the earthing system.

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4. SOIL SURVEY AND CALCULATIONS A soil survey has been carried out. The results of the survey are attached to this Invitation to Tender. The measured earth resistivity shall be corrected to that of the worst case by taking the moisture content of the soil at the time of resistivity measurement into consideration. 5. DESIGN CRITERIA 5.1 Depth of Earthing Grid The earthing grid should be installed at such a depth as to allow a minimum ground covering of 600mm. Where this depth is not practical as a result of increasing resistivity with depth, a proposed depth shall be submitted to the Engineer for approval before installation of the grid. 5.2 Resistance of the Earthing Grid The earth resistance of the grid shall not exceed 1 ohm. (This value becomes critical with two voltage systems connected to the same earthing grid). 5.3 Overhead Line Earth Wires The overhead line earth wires, where applicable, shall be connected to the substation earthing grid in accordance with BS CP 1013. 5.4 Type and Size of Main Earth Conductor The main earth shall be of 70mm2 stranded copper conductor and shall form a closed ring around the substation yard. 5.5 Fault Duration Assume fault duration of 5 seconds. 6. GENERAL CONSTRUCTION DETAIL Earthing points shall be provided on all equipment subject to earthing in accordance with BS COP 1013. Unless otherwise specified, joints are to be made using a “Cadweld” technique. 7. EARTHING OF OUTDOOR TYPE EQUIPMENT 7.1 Apparatus to be connected to the Earthing Grid All items listed for earthing in BS CP 1013 shall be duly connected to the earthing grid. 7.2 Conductor Type for connecting apparatus to the Earthing Grid All exposed copper shall be copper bar (tape), painted green except where designated as an approved position for applying a portable earth. The exposed copper for earthing the NER shall be painted black.

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7.3 Conductor Size necessary for connecting apparatus to the Earthing Grid All items subject to earthing in terms of BS CP 1013 shall be connected to the main earth by two separate subsidiary earth conductors, each of minimum cross-section 150mm2. If practical, these shall be connected to different sections of the main earth conductor mesh. The bonding bar of the three phases of each earth switch shall be earthed at the two extremes (outer phases). Mechanism boxes and kiosks shall be earthed independently of the associated device or steel structure on which they are supported, but in this case, branch connections of 80mm2 section copper (minimum) may be used providing it is laid and connected directly to a main or subsidiary earth conductor. 7.4 Connections Earth connections of equipment shall be made above ground level and all copper connection surfaces shall be tinned. The connecting face of the steelwork shall be clean and protected against electrolytic corrosion. This connection shall be on a vertical face. Foundation bolts shall not be used for earth connections. Surface exposed copper work may be bolted after the busbar connection points have been tinned and shall be to the satisfaction of the Engineer. Copper bolts, nuts and washers shall be used. 7.5 Portable Earths All equipment shall be provided with loop places to fix portable earths. See BS 7354, Clause 7.3.11. 7.6 Inspection by the Engineer After the earthing grid has been installed, welded and connected, the Engineer shall be notified for an inspection prior to backfilling. 7.7 Perimeter Fence Where a perimeter fence is applicable, the same shall be earthed separately from the main substation earthing grid. The fence is to be earthed by means of tails securely bonded to the fence poles at each side of each gate or removable panel, at corners, at each overhead line crossing and not less than 20m intervals. Fence gates are to be bonded to the earthed fence posts with flexible earthing straps. 8. EARTHING OF INDOOR TYPE EQUIPMENT 8.1 Apparatus to be connected to the Earthing Grid All items listed for earthing in BS CP 1013 shall be duly connected to the earthing grid. 8.2 Conductor Type and Size for the Main Indoor Loop A 6 x 40mm copper bar is to be fixed to the inner wall of the control room’s cable trench. This earth bar is to be mounted onto the P2000 trunking above the cable tray, using 6mm spring nuts. The bar is to be continuous around the entire inner wall of the trench. It is to be bonded to the station earth mat at the four corners of the room by means of stranded copper conductor with a cross-sectional area of at least 70mm2. All joints are to be made using “Copperflow”.

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8.3 Conductor Size necessary for connecting apparatus to the Earthing Grid Indoor equipment shall be bonded to the copper earth bar by means of stranded copper conductor or copper bar with a cross-sectional area of at least 70mm2. 9. EARTHING OF LIGHTNING MASTS AND ARRESTORS The earthing of surge arrestors and lightning masts shall be done in accordance with the relevant clauses of PEE Standard Number 130. 10. EARTH RODS Earth rods, couplers and clamps shall be supplied and installed in accordance with SABS 1063 – 1985, and SABS 0199. The copper of the rod shall be a hard-drawn copper having a composition that complies with SABS 806. If more than one earth electrode is required per group, these shall be spaced at least 5m apart and bonded with copper connections of not less than 150mm2 cross-sectional area. Each group of electrodes shall be connected to the main earth copper through a disconnecting link. The disconnecting link shall be a bolted copper strap and the faces shall be tinned. The link shall be housed in a concrete box (unless otherwise approved), which shall be fixed in position with box lid at 150mm above the unstoned ground level. Earthing electrodes shall be of the extendible rod type. If rods need to be extended, the external couplers shall be made from zinc-free phosphor bronze. The threads for the connector couplings shall be rolled and not machined. The top of earth rods shall be at the same depth as the earthing grid. 11. TESTS The Engineer shall be given at least one week’s written notice of the contractor’s intention to carry out tests on the earthing system. The following tests shall be carried out: -

Grid resistance

Step voltage

Touch voltage 12. INFORMATION TO BE SUPPLIED BY THE CONTRACTOR 12.1 Within Two Months after Appointment Assumptions made in designing the earthing grid. All calculated values of the final (and accepted) trial in accordance with Figure 26 of IEEE Std 80.

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12.2 Within Two Weeks after Testing Test Certificates. 13. QUALITY 13.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 13.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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REV NO.

DETAILS

AUTHOR


0

New Draft

PG

5 November 1999

1

Minor Amendments

PG

8 January 2001

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REV – DRAFT 1 13 DECEMBER 2001PEE STANDARD NO: 126

TRENCHING AND FOUNDATIONS (OUTDOOR EQUIPMENT) FILED-F:\DATA\STANDARDS\PEE_STD\STD 126 – TRENCHING AND FOUNDATIONS (OUTDOOR EQUIPMENT)\Std 126.doc




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TRENCHING, BACKFILLING & FOUNDATIONS FOR OUTDOOR ELECTRICAL EQUIPMENT IN

MAIN SUBSTATIONS

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REV – DRAFT 1 13 DECEMBER 2001

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TRENCHING, BACKFILLING AND FOUNDATIONS FOR OUTDOOR

ELECTRICAL EQUIPMENT IN MAIN SUBSTATIONS

TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5

3. DESIGN 6

4. EARTH WORKS 6 4.1 Site Preparation 4.2 Marking Out 4.3 Excavations (Foundations / Footings / Plinths) 4.4 Excavations (Cable Trenches) 4.5 Deep Excavations 4.6 Classes of Excavations 4.7 Dealing with Water 4.8 Backfilling (Cable Trenches) 4.8.1 The as-built data for the exact positions of buried services shall be

taken before backfilling starts

4.8.2 Bedding

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PAGE 4.8.3 Bedding Material 4.8.4 Bricks over MV Cable 4.8.5 Backfilling Material 4.8.6 Shortfall of Bedding and Backfill Material 4.8.7 Compaction

5. CONCRETE WORKS FOR FOOTINGS / FOUNDATIONS / PLINTHS FOR THE ERECTION OF OUTDOOR ELECTRICAL EQUIPMENT

8

5.1 Height above Ground Level 5.2 Strength Concrete 5.3 Reinforcing 5.4 Placing and Finishing

6. MEASUREMENT FOR PAYMENT 10



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1. SCOPE This Standard provides for the following substations: -

The excavation of cable trenches for the earthing grid, transformer MV power cables and auxiliary cables and backfilling and compaction of the same;

The design, excavation for and casting of footings / foundations / plinths for the erection of

outdoor electrical equipment. 2. REFERENCES The following standards are referred to in the text below and shall apply where quoted: - SABS 471 : Portland Cement (ordinary, rapid-hardening and

sulphate-resisting)

SABS 718 : Aggregates for Concrete

SABS 920 : Steel Bars for Concrete Reinforcement

SABS ENV 196 (Parts 2, 4, 6, 7, 21) : Methods of Testing Cement

SABS ENV 197 (Parts 1 and 2) : Composition, Specification and Conformity Criteria for Cements

SABS ENV 413 (Parts 1 and 2) : Masonry Cement

COP 10.1 (Section 2) : Climatic, Atmospheric and Environmental Conditions

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COP 10.1 (Section 9) : Safety Factors and other principles applicable to the Mechanical Strength Calculations of Outdoor Electrical Equipment, their Support Structures and Foundations

Act 85 of 1993 : Occupational Health and Safety Act 3. DESIGN The contractor shall be responsible for the design of the footings / foundations / plinths covered by the Project Specification and shall take cognisance of the following in the design thereof: -

The climatic, atmospheric and environmental conditions outlined in the Code of Practice Number 10.1 – Section 2 shall be considered.

The Safety and other principles outlined in the Code of Practice Number 10.1 – Section 9

shall apply.

Foundations shall be designed and the associated drawings signed by an ECSA registered Professional Engineer with at least 2 year’s relevant experience after registration as a Professional Engineer.

Drawings of footings / foundations / plinths shall clearly indicate the maximum forces and

turning over moments (in all directions) for which they have been designed, together with the safety factors used and other assumptions made, e.g. bearing pressure of the ground.

Footings / foundations / plinths for outdoor electrical equipment, whether mounted directly

(e.g. power transformers) or onto support structures, shall be cast with a minimum concrete strength of 20 Mpa.

Foundations shall be case in situ.

4. EARTH WORKS 4.1 Site Preparation The site where the foundations are to be cast is to be cleared of all shrubs and vegetation and disposed of to designated sites by the contractor. 4.2 Marking Out The foundations are to be clearly marked out on the ground to the dimensions shown on the drawings. Should the contractor excavate to dimensions in excess of those stipulated or permitted, he shall fill in the excess at his own expense in the manner specified or approved by the Employer. 4.3 Excavations (Footings / Foundations / Plinths) The excavations shall be dug to the neat lines marked out to the depths indicated on the drawing or to such greater depths as may be ordered or approved to ensure satisfactory founding. Except where otherwise specified or ordered, the excavation shall be carried out and trimmed to the outline of the concrete work shown on the drawings. The excavated surfaces will act as forms for the concrete work. Prior to the casting of any concrete, the bottom of the excavation shall be cleared of all loose material or soft material.

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4.4 Excavations (Cable Trenches) Trenches shall be marked out and dug in line and at right angles to the geographic layout of the outdoor switch bays and / or control room. Diagonal trenches are not acceptable. Trenches shall be sufficiently deep to allow the following minimum coverings from the top of cables: -

Medium Voltage Cable : 600mm

Low Voltage and Auxiliary Cables : 600mm Refer to PEE Standard Number 125 for detail on earthing conductor. 4.5 Deep Excavations The contractor’s attention is drawn to the relevant clauses in OHS – Act relating to excavation deeper than 1,5m. Where excavations are not adequately shored and supported and the sides collapse, no extra payment will be considered and the contractor shall remove the collapsed soil and replace and compact the soil after the foundations have been cast. The same applies where excavations have been damaged by storm water. 4.6 Classes of Excavations Excavations shall be classified and paid for as follows: -

Soft Excavations Material that can be loosened and removed by using hand tools and / or the bucket only of a back-acting excavator.

Intermediate Excavations

Material that, in the opinion of the Engineer, cannot be economically loosened without the assistance of pneumatic tools other than the bucket of a back-acting excavator.

Rock

Material that, in the opinion of the Engineer cannot be economically fragmented and loosened, except by drilling and blasting or the use of rock-breaking equipment other than what can be operated by hand.

4.7 Dealing with Water Excavations must be kept dry and free of water as far as possible. No cables are to be laid in water. Payment for dealing with water shall be based on dayworks rates. 4.8 Backfilling (Cable Trenches) 4.8.1 The as-built data for the exact positions of buried services shall be taken before back-

filling starts 4.8.2 Bedding Cables shall be bedded below and above as follows: -

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Medium voltage cable : 100mm

Low voltage and auxiliary cables: 50mm 4.8.3 Bedding Material Material for bedding electricity supply and auxiliary cables shall be a selected soil of granular (sandy) nature, free of clay, vegetation, foreign matter, lumps and stones exceeding 15mm in size. Bedding material shall preferably be selected from the excavations on site and shall be sifted. Where insufficient quantities of suitable bedding material exist on site, it shall be imported. 4.8.4 Bricks over MV Cable One layer of clinker brinks (to be supplied by the contractor) shall be placed directly on top of the bedding in respect of MV cables to indicate the position thereof. Approximately 4.5 bricks shall be placed per meter of cable. 4.8.5 Backfilling Material Backfilling other than bedding, shall contain little or no vegetable matter. It shall also exclude stone of average dimension exceeding 150mm. It shall not contain rubble or debris in order that it can be placed without significant voids and so compacted as to avoid significant settlement. 4.8.6 Shortfall of Bedding and Backfill Material Where there is a shortfall of suitable bedding or backfill material, material shall be imported from a recognised source. 4.8.7 Compaction The backfill material shall be at optimum moisture content. Each layer of backfill shall be placed to a thickness (after compaction) of 150mm. The bedding blanket shall only be lightly compacted to avoid damage to the cables. Backfill material other than bedding shall be compacted to 98% of Proctor density using hand stampers. 5. CONCRETE WORKS FOR FOOTINGS / FOUNDATIONS / PLINTHS FOR THE ERECTION OF

OUTDOOR ELECTRICAL EQUIPMENT 5.1 Height above Ground Level The finished cast level of all footings / foundations / plinths shall be at least 150mm above final ground level. The finished height of the power transformer plinths shall be determined in co-operation with the manufacturer of the transformers, but shall in any event be not less than 150mm above final ground level. The tops of all foundations shall be horizontal and level.

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5.2 Concrete Strength The concrete used in the footings / foundations / plinths shall be of a strength of at least 25 MPa. Either concrete mixed on site or ready-mixed concrete is acceptable as long as it meets the required specifications. The contractor could be called upon to take sample cubes and have them tested to ensure that the required concrete strength is achieved. The concrete shall be mixed without excessive water. The materials used in the strength concrete shall meet the following criteria: -

Cement Cement used shall be ordinary Portland Cement or when required, rapid-hardening cement in accordance with SABS 471.

Cement that is stored on site shall be kept under cover that provides proper protection against

moisture and other factors that may promote deterioration. Contaminated or spoiled cement may not be used and must be removed from site.

Aggregates

All aggregates for concrete shall comply with the requirements of SABS 1083.

Water Water shall be clean and free from injurious amounts of acids, alkalis, organic matter and other substances that may impair the strength or durability of concrete.

5.3 Reinforcing

Design Where reinforcing is required in terms of the design, the concrete shall be suitably reinforced with steel to withstand the maximum loadings to which it could be subjected.

Material

The reinforcing of bars shall comply with the relevant requirements of SABS 920. Welded steel fabric shall comply with the relevant requirements of SABS 1024.

Storage

Steel shall be stacked off the ground as to prevent distortion, and shall be prohibited from aggressive environments of contamination. The steel must be clean from oil, paint or loose rust.

Lapping and Tying

All joints are to be lapped by at least 25 times the bar diameter and tied with 1.6mm annealed steel wire.

Bending and Working

All bending of steel must be done cold.

Cover Reinforcing is to be held securely in place during casting and is to have a minimum cover of at least 75mm.

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5.4 Placing and Finishing The Engineer shall be given at least 2 (two) days’ written notice of the contractor’s intention to cast footings / foundations / plinths. The Engineer may want to inspect excavations before placing of the concrete. The bottom of excavations shall be damp to optimum moisture content and compacted to 98% of Proctor density before any concrete is cast. Shuttering must be sturdy, square and level. Properly supported joints in shuttering shall be sealed to prevent seepage of cement from the concrete. Concrete shall be cast without interruption. In cases where it is not practical to do so, the written approval of the Engineer shall be obtained in which case approved jointing methods shall be employed. Vacuum system shall be applied during and after placing to ensure removal of trapped air / air voids in the concrete. Concrete shall not be cast when the temperature is below 4oC. Concrete shall be protected against frost or any other weather conditions, which may influence the setting and curing of the concrete. No loads may be applied to any concrete before it has been properly cured. Foundations shall have no sharp corners or edges. Corners and edges shall be levelled at 45o with a width of 50mm. Immediately after the structures have been installed and finally aligned, all the base plates shall be grouted-in, using a non-shrink type of grouting, strictly in accordance with the supplier’s instructions. The grouting shall be finished off where it protrudes beyond the base plates such that a run-off for water is provided. 6. MEASUREMENT FOR PAYMENT Tenders shall be submitted with detail regarding the expected quantities for the following items. Payment shall be based on actual quantities encountered on site up to a maximum of the tendered quantities. The tendered quantities should therefore constitute maximum quantities. 6.1 Excavation for footings / foundations / plinths and trenches m3

6.2 Backfilling of trenches m3

6.3 Laying of earth conductor and auxiliary cables m3

6.4 Concrete for footings / foundations / plinths m3

6.5 Importing bedding and backfill material (the price includes transport within a radius of

15km) m3

6.6 Disposal of soil (the price includes transport within a radius of 15km) m3

6.7 Steel for reinforcing m3

6.8 Transport beyond a radius of 15km (only applicable to 6.5 and 6.6) m3

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7. QUALITY 7.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 7.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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REV NO.

DETAILS

AUTHOR


0

New Draft

PG

5 November 1999

1

PG

13 December 2001

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OUTDOOR CIRCUIT BREAKERS FILED-F:\DATA\STANDARDS\PEE_STD\STD 128 – OUTDOOR CIRCUIT BREAKERS\Std 128.doc




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OUTDOOR CIRCUIT BREAKERS

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BLANK PAGE

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TABLE OF CONTENTS

PAGE 1. SCOPE 6

2. REFERENCES 6

3. PARTICULARS OF THE DISTRIBUTION SYSTEM 7 3.1 Voltage and Frequency 3.2 Non-standard Phase Sequence 3.3 Neutral Earthing

4. REQUIREMENTS FOR THE OUTDOOR CIRCUIT BREAKER 7 4.1 General 4.2 Operating Mechanism 4.2.1 General 4.2.2 Motor Wound Spring 4.2.3 Housing 4.2.3.1 Degree of Protection 4.2.3.2 Anti-Condensation Heater 4.2.3.3 Cabinet Light 4.2.3.4 External Appliances 4.2.4 Electrical Operations 4.2.5 Low Voltage Fuses

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PAGE 4.2.6 Mechanical Operation 4.2.7 Indicators and Counter 4.2.8 Secondary Terminals 4.2.9 Terminal Strips and Gland-Plates 4.2.10 Wiring, Termination and Identification 4.2.11 Closing and Trip Coils 4.2.12 Auxiliary Switches 4.2.13 Key Interlocks 4.2.14 Metal Finish 4.2.15 Earthing 4.2.16 Ratings 4.2.17 Insulators 4.2.18 SF6 Gas as Insulation and ARC Quenching Medium 4.2.18.1 Control and Monitoring 4.2.18.2 First Filling 4.2.19 Steel Support Structure 4.2.20 Spares and Special Tools 4.2.21 Marking / Labelling / Documentation 4.2.21.1 Rating Plates 4.2.21.2 Labels 4.2.21.3 Drawings 4.2.21.3.1 General 4.2.21.3.2 Convention 4.2.21.4 Test and Test Certificates 4.2.21.5 Instruction / Maintenance Manuals


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ANNEXES

ANNEX A Outdoor Circuit Breakers


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1. SCOPE This specification provides for the design, manufacture, testing, supply and delivery of outdoor type circuit breakers. 2. REFERENCES The circuit breakers shall, where applicable, be manufactured and tested in accordance with the relevant requirements of the Standards listed below: - PEE Standard Number 100 : Protection and Auxiliary Relays

PEE Standard Number 101 : SCADA Interface Requirements

PEE Standard Number 113 : Indoor Control Panels

NRS 003 : Metal-Clad Switchgear

SABS 1507 : Electric Cables with Extruded Solid Dielectric Insulation for Fixed

Installations (300/500 V to 1900/3300 V)


IEC 56 : High Voltage AC Circuit Breakers The following Standards are referred to in the text below and are only applicable as specifically called for in this specification: - SABS 763 : Hot-Dip (Galvanised) Zinc Coatings (Other than on Continuously

Zinc-coated sheet and wire)

SABS 0111 : Part 1: Engineering Drawing – General Principles

SABS 1222 : Enclosures for Electrical Equipment (Classified according to the Degree of Protection that the Enclosure provides)

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IEC 168 : Tests on Indoor and Outdoor Post Insulators of Ceramic Material or Glass for Systems with Nominal Voltage greater than 1000 V

IEC 269 – 1 : Low Voltage Fuses: Part 1 – General Requirements

IEC 269 – 2 : Low Voltage Fuses: Part 2 – Supplementary Requirements for Fuses for use by Authorised Persons (Fuses mainly for Industrial Application)

3. PARTICULARS OF THE DISTRIBUTION SYSTEM 3.1 Voltage and Frequency The equipment will be installed on a 3 phase, 3 wire, 50 Hz system, operating at a nominal and highest voltage as stated in the Project Specification and / or the General Particulars and Guarantees. 3.2 Non-Standard Phase Sequence The phase sequence is non-standard (R-B-Y-R) and care must be taken to ensure meter and relay circuits that are phase rotation sensitive, are correctly wired for this rotation. 3.3 Neutral Earthing The neutral points are effectively earthed. 4. REQUIREMENTS FOR THE OUTDOOR CIRCUIT BREAKER The circuit breaker shall comply with the requirements of IEC 56, where these requirements are modified by the following text: - 4.1 General The circuit breaker shall be of the 3-pole type, suitable for auto reclosing. The poles shall be mechanically linked together (ganged) in such a way that they can all only be opened and closed together. The preferred insulating and arc-quenching medium is SF6 (sulphur hexafluoride) gas. 4.2 Operating Mechanism 4.2.1 General The preferred operating mechanism is a mechanical system in which energy is stored in a spring that is charged by an electric motor. Alternative types of operating mechanism may be submitted for approval. 4.2.2 Motor Wound Spring The motor shall be supplied complete with thermal and overload protection and a suitable means of isolating the supply to the motor. The motor shall charge the spring automatically after each closing operation.

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Provision shall also be made for manually charging the closing spring with the aid of a crank to be supplied with each circuit breaker. The crank handle shall be stowed in a convenient position inside the cubicle housing the operating mechanism. 4.2.3 Housing 4.2.3.1 Degree of Protection The operating mechanism housing shall preferably take the form of a cabinet fitted with at least one hinged door. Doors shall be equipped with padlocking facilities with a 12mm diameter hole to accommodate the padlock shank. The cabinet shall have a degree of protection of at least IP55 in accordance with SABS 1222. Where such items are provided with ventilation or drain holes and it is intended that the equipment is to be operated with the holes open, the items shall have a degree of protection of at least IP55 in accordance with SABS 1222. All hinges, fasteners, handles, etc. shall be made of corrosion-resistant material. Gaskets shall be of neoprene or heavy-duty foam plastics. Felt or rubber gaskets shall not be used. 4.2.3.2 Anti-Condensation Heater As an aid to preventing condensation, suitably rated heaters shall be fitted in mechanism cabinets. The AC supply for these heaters will be 230 V. Single heaters shall be permanently connected. Where two-stage heaters are provided, one stage shall be permanently connected. Individual fusing of the heaters is required in each cabinet. The heater shall be fused separately from other circuits. A fuse shall be provided in the live side of the heater circuit and a solid withdrawable link in the neutral. No heater-isolating switch shall be provided. All terminals for the incoming AC supply to the fuses and the fuse live terminals shall be shrouded. 4.2.3.3 Cabinet Light A light with suitable switch shall be fitted in the cabinet. 4.2.3.4 External Appliances A 230 V, 15 A socket shall be provided in the cabinet for the use of a portable lamp and electrical hand-tools. An earth leakage circuit breaker shall not be fitted. 4.2.4 Electrical Operations It shall be possible to electrically operate the circuit breaker either from a remote control or locally at the circuit breaker. The following switches shall be mounted in the operating mechanism cabinet: -

An OPEN/CLOSE switch for electrical opening and closing of the circuit breaker;

A two-way selector switch labelled REMOTE/LOCAL. When in the REMOTE position, it shall disable the local OPEN/CLOSE switch. When in the LOCAL position, it shall disable the OPEN/CLOSE switch in the remote control panel.

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4.2.5 Low Voltage Fuses All fuses shall be cartridge type and in accordance with the requirements of IEC 269-1 and IEC 269-2. Carriers for fuse links shall be black and those for solid links, white. Fuses and links on the same sub-circuit shall be mounted adjacent to one another. 4.2.6 Mechanical Operation A suitable switch labelled OPEN/CLOSE, for mechanical opening and closing of the circuit breaker, shall be provided inside the operating mechanism housing. 4.2.7 Indicators and Counter The circuit breaker shall have definite mechanical indication; clearly visible to personnel standing on the ground with the cabinet door closed, to show the following: -

Circuit breaker open/close;

Stored energy device charged or discharged;

An operation counter mounted on the operating mechanism shall be clearly visible to personnel standing on the ground.

4.2.8 Secondary Terminals All terminals for connection to external circuits shall be of the spring-load type. Not more than two conductors shall be connected to any side of a terminal. 4.2.9 Terminal Strips and Gland-Plates All auxiliary switches, internal wiring and other equipment requiring connection to external apparatus shall be wired to suitable terminal strips in the enclosure. Unless otherwise approved, each terminal strip shall be provided with at least 10% spare terminals, with a minimum of two. The arrangement of the terminal strips in the equipment shall facilitate the entry of the incoming control cables. Any control cabling will be multi-core, PVC-insulated, single-wired armoured, PVC-sheathed, complete with mechanical type glands, for which a removable brass or other approved gland-plate of the minimum size specified in the Schedule of General Particulars and Guarantees shall be provided adjacent to the terminal board. To facilitate cable entry and connection, the distance between the bottom of the terminal strip and the gland-plate shall be at least 120mm unless otherwise approved. 4.2.10 Wiring, Termination and Identification All secondary wiring shall consist of multi-stranded copper conductors suitably braced, clipped or laced to prevent vibration.

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All connections shall be terminated in compression type or crimped type lugs compatible with the device to be connected. Connections to equipment on swing doors shall be arranged vertically over the hinge so as to give a twisting motion and not a bending motion to the conductors. All terminals, labels, etc. shall be completely accessible after the wiring and cabling have been completed. All auxiliary wiring shall be insulated in accordance with SABS 1507 to withstand 2kV to earth for one minute. All internal secondary wiring connecting onto terminal strips for external connections shall be numbered at both ends with an approved type of marking device, the numbering being permanently marked with black letters impressed on a white background. Interlocking type ferrules are preferred and shall match the size of the wire onto which they will be fitted. The wiring shall be numbered in accordance with Annex A of NRS 003: 1991. The wiring between the auxiliary contacts and the secondary terminal strip shall have a cross-sectional area of at least 2,5mm2. 4.2.11 Closing and Trip Coils One closing coil and two independent trip coils shall be provided. The coils shall be rated for the voltage specified in the Schedule of General Particulars and Guarantees. 4.2.12 Auxiliary Switches Auxiliary switches shall be provided to energise the circuit breaker open lamp, closed lamp and spring-charged lamp located on the remote control panel. The circuit breaker shall be provided with at least four spare normally open and four spare normally closed auxiliary contacts. 4.2.13 Key Interlocks An interlock and key shall be provided on the circuit breaker, which shall not permit the key to be released unless the circuit breaker is in the open position. Compatible locks and keys shall also be provided for the disconnectors. Spare keys to operate these locks shall be provided. 4.2.14 Metal Finish All ferrous parts associated with the circuit breaker and its support structure shall be hot-dip galvanised in accordance with SABS 763. All parts other than ferrous parts shall be made of corrosion-resistant material and shall be finished to the approval of the purchaser. Should any galvanising be damaged during transit or erection, this shall be rectified using an approved method.

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4.2.15 Earthing All metal parts not carrying current will be earthed to the main substation yard earthing system. Suitable earthing terminals shall be provided. 4.2.16 Ratings The required circuit breaker ratings are specified in the Schedule of General Particulars and Guarantees. 4.2.17 Insulators All insulators shall be of the outdoor type, suitable for high-pressure water washing live circuit conditions and shall comply, where relevant, with IEC 168. Details of the insulators offered shall be stated in the Schedule of General Particulars and Guarantees. The minimum creepage distance required between phase and earth, in mm per kV of the highest r.m.s. phase-to-phase voltage is specified in the Schedule of General Particulars and Guarantees. The creepage distance of the break chamber shall not be less than that of the support insulators. 4.2.18 SF6 Gas as Insulation and ARC Quenching Medium 4.2.18.1 Control and Monitoring A temperature compensated pressure gauge shall be provided and shall be so positioned that it can easily be read by personnel standing on the ground, assuming the circuit breaker is mounted on the structure specified in Clause 2.3.18. Associated with this pressure gauge, low gas pressure detection relays shall be provided in the control panel that initiates an alarm when the pressure falls below a specified threshold and initiates an operation lock-out of the circuit breaker when the pressure falls below an even lower threshold. 4.2.18.2 First Filling The first filling of SF6 gas is to be provided. 4.2.19 Steel Support Structure The circuit breaker is to be supplied complete with a steel support structure suitable for mounting on a concrete plinth. Suitable galvanised steel bolts for securing the circuit breaker to the support structure shall also be supplied. The mounting height of the circuit breaker shall be such that the minimum distance between the bottom of the support insulators and ground shall be as specified in the Schedule of General Particulars and Guarantees. 4.2.20 Spares and Special Tools Details, including itemised prices, of any recommended spare parts to cater for anticipated or possible maintenance of the equipment shall be stated in a covering letter.

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Details, including itemised prices, of any special tools required for the installation and maintenance of the equipment, shall also be stated in the covering letter. 4.2.21 Marking / Labelling / Documentation The language used for rating plates, labels, drawings, certificates and manuals shall be English. 4.2.21.1 Rating Plates Rating plates shall be engraved, stamped or embossed on intrinsically corrosion-resistant material and shall be externally mounted. The information to be displayed shall be as specified in IEC 56. Anodised aluminium shall not be used for externally fitted rating plates except for rating plates of necessity fitted inside the mechanism cabinet. 4.2.21.2 Labels Labels shall be securely fixed with screws or pop rivets. The material of the labels and fixings shall be of intrinsically corrosion-resistant material. Labels shall be so positioned that personnel standing on the ground can easily read them. The successful tenderer shall be forwarded a list with the labels’ wording. 4.2.21.3 Drawings 4.2.21.3.1 General The original drawings shall be prepared in such a manner that they comply fully with the requirements of SABS 0111 in order that acceptable microfilm versions can be made from them. Where the supplier uses a CAD drawing system, he shall provide copies of the drawings on an Auto-CAD compatible file. The following drawings are required for approval within eight weeks of receipt of the Council’s letter of acceptance: -

(a) Outline and general arrangement;

(b) Foundation details showing position and size of holding-down bolts;

(c) Schematics;

(d) Wiring diagram. 4.2.21.3.2 Convention Schematic wiring diagrams to be submitted to the purchaser for approval shall adopt the following convention: -

Main contacts are in the fully open position;

Relay coils, push buttons, etc. are inactive.

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4.2.21.4 Test and Test Certificates Certified copies of test certificates showing the results of type tests shall be included with the tender. The results of routine tests in accordance with IEC 56 shall be submitted for approval prior to delivery of the equipment. If the equipment on offer is effectively identical to equipment previously supplied, then type test certificates are not required. In this case, the supplier is to state the PEE contract number of the previously supplied equipment. 4.2.21.5 Instruction / Maintenance Manuals Triplicate copies of installation, operation and maintenance manuals for the equipment are to be submitted before delivery. 5. QUALITY 5.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 5.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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9 January 2001

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OUTDOOR CIRCUIT BREAKERS FILED-F:\DATA\STANDARDS\PEE_STD\STD 128 – OUTDOOR CIRCUIT BREAKERS\Std 128 – Annex A.doc

ANNEX A


Item Parameter Unit Requirement Offer

Service Conditions To PEE Std ______ Details of circuit breaker

a) Manufacturer b) Class (Indoor / Outdoor) c) Number of Poles d) Interrupter insulating medium (p) e) Arc-quenching medium

- Details of coupling required for filling - Maintenance of non-return valve

xxx xxx

Outdoor 3

SF6 SF6 xxx xxx

Rating a) Rated nominal voltage b) Rated insulation level

- Impulse withstand voltage (peak) - Power frequency withstand voltage (rms)

c) Rated frequency d) Rated normal current e) Rated short circuit breaking current f) Short circuit duration g) Rated short circuit making current h) Rated line-charging breaking current i) Rated cable charging breaking current j) Rated small inductive breaking current k) Rated out-of-phase breaking current l) First pole to clear factor m) Rated transient recovery voltage for terminal

faults n) Rated characteristics for short-line faults o) Rated operating sequence p) Circuit breaker suitable for gang-operation

rapid auto-reclosing q) Opening time r) Break time s) Number of breaks in series per pole t) Closing time

kV

kV

kV Hz A kA S kA A A A A

V s s s

xxx

Operating Mechanism a) Type of mechanism b) Trip free or Fixed trip c) Lock out preventing closing (anti-pumping

relay fitted) d) If spring operated: -

- Spring charging motor - Rated supply voltage - Max. power consumption - Max. charging time - Manual charging possible - Spring charged indicator

e) Trip Coil - Number - Rated voltage - Power consumption

f) Closing Coil - Number - Rated voltage - Power Consumption

of 2 (Annex A)

(Annex A)


OUTDOOR CIRCUIT BREAKERS FILED-F:\DATA\STANDARDS\PEE_STD\STD 128 – OUTDOOR CIRCUIT BREAKERS\Std 128 – Annex A.doc

Auxiliary Switches a) Number of auxiliary switches

- Normally open - Normally closed

b) Rating - Normal - Fault conditions for 1 sec.

c) Secondary terminals - Make - Type

Dimension, Weight and other Particularsa) For oil circuit breakers

- Mass complete circuit breaker without oil - Mass of oil - Oil quality - Number of tanks

b) Gas circuit breakers - Insulating medium (Vacuum, SF6) - Total weight - Normal gas pressure - Min. gas pressure for normal operation - Max. gas pressure for normal operation - Volume of gas per pole at N/cm2 - Leakage of gas per year

xxx

Drawing indicating all dimensions such as height, depth, width, support structure dimensions, details required for the design of the foundation

Secondary Terminals

Local Control Enclosure

Metal Finish

Insulator Data

Clearances a) Min. clearances in air

- Between poles - To earth

b) Lowest part of insulator above ground level

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OUTDOOR MARSHALLING KIOSKS FILED-F:\DATA\STANDARDS\PEE_STD\STD 129 – OUTDOOR MARSHALLING KIOSKS\Std 129.doc




________________

OUTDOOR MARSHALLING KIOSKS

____________________________

REV – DRAFT 2 27 MARCH 2007

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BLANK PAGE

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TABLE OF CONTENTS

PAGE 1. SCOPE 4

2. MATERIAL 4

3. DESIGN 4 3.1 Size 3.2 Terminals 3.3 Door and Protection 3.4 Cable Entry 3.5 Heaters and other 230 V accessories 3.6 Earth Bar



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1. SCOPE This Standard provides for the supply and, where called for in the Project Specification, the installation of outdoor type marshalling boxes. A kiosk will be used per HV switch bay. The cabling from other outdoor equipment shall be marshalled in the kiosk and then cabled to the indoor control cubicles. 2. MATERIAL Unless otherwise approved, the marshalling kiosks shall be fabricated from 3CR12. Full details of the fabrication shall be submitted to the Engineer for his specific approval before manufacture commences. 3. DESIGN Where kiosks are ordered as part of a supply and installation contract involving most part of the HV bay, the kiosks shall preferably be free-standing. Kiosks mounted on other support structures will be considered by the Employer, provided that details are submitted by the Contractor for approval in good time and; No drilling post galvanising will be done on any structures – not for the kiosk and also not for

the auxiliary cable trays up into the kiosk.

3.1 Size Where kiosks are ordered as part of a supply and installation contract involving most part of the HV bay, the kiosks shall be of adequate size to suit the particular requirements. The cubicle interior shall be at least 800mm wide, 300mm deep and 800mm from the gland plate to the top. 3.2 Terminals 3.2.1 Size Terminals shall be sized as per Code of Practice 9.1. 3.2.2 Number For quotation purposes, Tenderers shall allow for 90 terminals arranged in 3 rows of 30 each.

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3.3 Door and Protection Two (2) lockable hinged doors shall provide access. The top of the kiosk shall be sloped to prevent accumulation of water, and the base, while vermin-proofed, shall be well ventilated. No ventilation openings will be allowed on the sides. Doors shall be provided with door stops that will prevent doors from being opened too far. Once opened, the door stops shall lock the doors in the open position to prevent wind damage. 3.4 Cable Entry Ideally, cables should enter the box from vertically below. Boxes should therefore be placed over cables trenches. Where the number of cable entries is specified in the Project Specification or in the case of a turn-key project, spare terminals shall be provided and these shall number at least 10% of the known terminal connector requirements. The cable gland plate shall be at least 1 200mm above ground level and shall be made up of several separately removable gland plates for ease of drilling. The glanding area shall be suitable for all known cables as well as a minimum of 20% free space for the glanding of future cables. 3.5 Heaters and other 230 V accessories Marshalling kiosks shall be fitted with anti-condensating heaters, a light that will be switched by opening the door and a socket outlet. The 230 V supply shall be channelled via the indoor relay panel associated with the same bay. 3.6 Earth bar A 20 x 5 mm copper earth bar shall be provided on stuts on the bottom gland plate of the box. 4. QUALITY 4.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 4.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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PG

5 November 1999

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Minor updates

PG

9 January 2001

2 Change design & add more detail PG 27 March 2007

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LIGHTNING MASTS AND ASSOCIATED LIGHTING FILED-F:\DATA\STANDARDS\PEE_STD\STD 130 – LIGHTNING MASTS AND ASSOCIATED LIGHTING\Std 130.doc




________________

LIGHTNING MASTS AND ASSOCIATED

LIGHTING

____________________________


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BLANK PAGE

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LIGHTNING MASTS AND ASSOCIATED LIGHTING

TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5

3. DEVIATIONS FROM SABS 0225 AND SABS 03 AND / OR SPECIFIC REQUIREMENTS

5

3.1 Wind Pressure, Terrain and Gusts 3.2 Safety Factor 3.3 Length 3.4 Material 3.5 Galvanising 3.6 Welds 3.7 Condensate 3.8 Earthing

4. REQUIREMENTS FOR LIGHTS 6 4.1 Cross Arms 4.2 Lamps 4.3 Access Hole

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PAGE 5. QUALITY 7 5.1 General 5.2 Quality Assurance Provisions


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1. SCOPE This Standard provides for the design, manufacture, testing, supply and delivery of lightning masts for the protection of all outdoor electrical equipment in main substation yards. 2. REFERENCES The lightning masts shall be designed, manufactured and tested in accordance with the relevant requirements of the latest versions of the following standards: - SABS 0225 – Code of Practice for The Design and Construction of Lightning Masts SABS 03 – Code of Practice for The Protection of Structures against Lightning The following standards are referred to in the text below and are only applicable as specifically called for in this specification: - SABS 0199 – The Design and Installation of an Earth Electrode PEE Standard Number 120 – Atmospheric and Environmental Conditions 3. DEVIATIONS FROM SABS 0225 AND SABS 03 AND / OR SPECIFIC REQUIREMENTS 3.1 Wind Pressure, Terrain and Gusts The provisions of PEE Standard Number 120 shall apply. 3.2 Safety Factor A minimum safety factor of 2.5 shall apply. 3.3 Length The masts shall be at least 18m in length (spike excluded) and shall be erected on properly designed plinths with suitable size bolts.

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The spike shall be 1m in length and shall be sharpened to a point. 3.4 Material The masts shall be manufactured from high tensile steel to SAE/AISI 950X. The minimum tensile strength of the steel shall be 500 MPa. 3.5 Galvanising Each completed section shall be hot-dipped galvanised. 3.6 Welds Only seam welds will be accepted. 3.7 Condensate Possible condensation on the inside of the pole shall be adequately drained at the base. No pockets allowing water accumulation will be allowed. 3.8 Earthing An earth bracket shall be welded at the base of the mast using 50mm x 2,8mm mild steel as per attached drawing number YJ 000114. Where installation is called for in the Project Specification, a crow type earthing system in accordance with SABS 0199 shall be installed for each lightning mast. This system shall be connected to the main earthing grid with a minimum 70mm2 copper conductor. Bends in the earthing connector shall not exceed 35o. 4. REQUIREMENTS FOR LIGHTS 4.1 Cross Arms The masts must be supplied with cross-arms/half clamps and 4 x 2-way brackets for supporting high-pressure sodium fittings as specified. The cross-arms shall be fitted at a height from the base of approximately 14m. 4.2 Lamps Each of the 4 x 2-way brackets shall be fitted with 2 lamps fulfilling the following criteria per lamp: -

TYPE HIGH PRESSURE SODIUM

Voltage (V)

230

Power (W)

250

4.3 Access Hole An access opening 100mm x 100mm is required near the base of the pole for the fixing of lightning control gear and cables located on the side of the pole.

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It shall not be located on the same side as the earthing terminals. The opening shall be adequately reinforced such that the strength of the pole is not decreased at this point. 5. QUALITY 5.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 5.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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REV NO.

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AUTHOR


0

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PG

5 November 1999

1

Minor updates

PG

9 January 2001

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REV – DRAFT 3 1 AUGUST 2010 PEE Standard 138 : Construction of High Voltage Substations

By Period Contract



________________

CONSTRUCTION OF HIGH VOLTAGE

SUBSTATIONS BY PERIOD CONTRACT

____________________________

REV – Draft 3 1 August 2010

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By Period Contract

BLANK PAGE

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By Period Contract




CONSTRUCTION OF HIGH VOLTAGE SUBSTATIONS BY PERIOD CONTRACT

TABLE OF CONTENTS

INTRODUCTION PAGE

1. INTRODUCTION 9

2. DEFINITIONS 9

3. REFERENCES 10 3.1 Conditions of Contract 3.2 Standards and Codes of Practice CONTRACTUAL

4. APPOINTMENT SEQUENCE 10

5. TIME FOR COMPLETION 11

6. VARIATION OF CONTRACT PRICE 11 6.1 TRENCHING AND BACKFILLING OF CABLE TRENCHES 6.2 BACKFILLING EXCAVATIONS / IMPORTED MATERIAL

7. CONTRACT PRICE ADJUSTMENT 11

8. RATES OF EXCHANGE 12

9. CPA AND ROE NOT SUBJECT TO RETENTION 12

10. SCHEDULE OF RATES (PART C2.2) 12 10.1 Supply Rate 10.2 Termination of auxiliary cables 10.3 Time related P&G’s

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By Period Contract

10.4 Steel Support Structures - Item No 9 10.5 Compact outdoor switchgear – CT (Item 13.14) 10.6 Impact of Primary Equipment (Part C2.2 – Items 24.2 to 24.5) 10.7 Breaker Fail - Item 24.20

11. EMPLOYER'S SPECIFIC REQUIREMENTS IN THE ANNEXURES OF PART T2 OF INVITATION TO TENDER FORMS PART OF THIS SPECIFICATION

13

12. APPOINTMENT TO COVER ALL WORK 13

GENERAL DESIGN CRITERIA

13. PARTICULARS OF DISTRIBUTION SYSTEM 14

14. MINIMUM REQUIREMENTS 14

15. DESIGN AND LAYOUT OF EQUIPMENT TO TAKE LEGISLATION INTO

ACCOUNT

14

16. PHASE SEPARATION AND EQUIPMENT SPACING 14

17. ATMOSPHERIC AND ENVIRONMENTAL CONDITIONS 14

18. SAFETY FACTORS AND OTHER PRINCIPLES APPLICABLE TO MECHANICAL

STRENGTH CALCULATIONS

15

19. DESIGN TEAM AND PROJECT MANAGER 15

20. DIMENSIONS ON EMPLOYER’S DRAWINGS TO BE VERIFIED 15

21. DRAWINGS 15

21.1 Submission of First Set Of Drawings for Comment

22. SELECTION OF SURGE ARRESTERS 15

23. SOIL TYPE 15

24. EARTH MAT 16

25. PROTECTION AND CONTROL 16

26. IEC61850 SUBSTATION BUS 16 26.1 Introduction 26.2 Speed 26.3 Communication Medium

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By Period Contract

26.4.1 HMI 26.4.2 Gateway & Configuration Tool 26..4.3 Switches 26.5 Firmware and Software 26.6 Engineering access to the IEC61850 Substation Bus

27. DESIGN CALCULATIONS TO BE MADE AVAILABLE UPON REQUEST 18

28. PROGRESS REPORTS 18 EQUIPMENT TO BE DESIGNED,

MANUFACTURED AND SUPPLIED TO PEE STANDARDS

29. FOUNDATIONS 18

30. SUPPORTING STRUCTURES 18

31. OUTDOOR TYPE DISCONNECTOR 19

32. CIRCUIT BREAKER 19

33. INTERLOCKING 19

34. OUTDOOR TYPE CURRENT TRANSFORMERS 19

35. SURGE ARRESTERS 19

36. HV BUSBARS 19

37. POWER TRANSFORMERS 20 37.1 Neutral Links

38. EARTHING 20

39. CONTROL PANELS 20 39.1 Panel Wiring

40. RELAYS 21

41. AUXILIARY CABLES 21

42. OUTDOOR MARSHALLING BOXES 21

43. POWER CABLES (12 & 24 kV) 21

44. MV INDOOR METAL-CLAD SWITCHGEAR BOARD 21

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By Period Contract

45. BATTERY TRIPPING UNIT 22

46. NEUTRAL EARTHING RESISTOR 22

SUPPLIED BY OTHERS

47. EQUIPMENT POSSIBLY SUPPLIED BY OTHERS 22

BASE MATERIAL STANDARDS

48. ALUMINIUM AND ALUMINIUM ALLOYS 22

49. DISSIMILAR METALS 23

MISCELLANEOUS

50. BOLTS AND NUTS 23

EQUIPMENT FINISHING

51. GALVANISING 23

52. PAINTING 23

53. LABELS 23

FILLINGS AND ACCESSORIES

54. OIL 24

55. SF6 GAS 24

56. SPARES 24

57. SPECIAL TOOLS 24

CONSTRUCTION

58. DRAWINGS TO BE SIGNED AND APPROVED BEFORE ANY CONSTRUCTION

STARTS

24

59. LIVE SUBSTATION 24

59.1 Application for a shut down

60. LINE, LEVEL, SQUARENESS, PLUMB 25

61. SITE MEETINGS 25

62. SITE CONDITIONS 25

63. TRENCHING, CABLE LAYING AND BACKFILLING 25 63.1 Outdoor Auxiliary Cables to be laid in ducts

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By Period Contract

64. MEDIUM VOLTAGE CABLE ENDS AND JOINTS 26

65. LEGISLATION AND OBLIGATIONS OF THE CONTRACTOR 26

TESTING AND COMMISSIONING

66. TESTS 29

66.1 General 66.2 Type Tests 66.3 Circuit Breakers 66.4 Routine and Sample Tests 66.5 Site Testing

67. FINAL COMMISSIONING 30 MAINTENANCE PERIOD

68. FAULTS DURING MAINTENANCE 30

ANNEXURE A - Tables

Table 1 Basic Panel Table 2 Impact of additional equipment on basic panel Table 3 Impact of additional relays on basic panel Table 4 Standard Relay Panel 1 Table 5 Standard Relay Panel 2 Table 6 Standard Relay Panel 3 Table 7 Standard Relay Panel 4 Table 8 Standard Relay Panel 5 Table 9 Standard Relay Panel 6 Table 10 Standard Relay Panel 7 Table 11 Standard Relay Panel 8 Table 12 Standard Relay Panel 9 Table 15 Standard Relay Panel 12 Table 16 Standard Relay Panel 13 Table 17 Standard Relay Panel 14 ANNEXURE B - Sketches

Sketch 1

Relay Panels – Primary Equipment Impact - Disconnector

Sketch 2

Relay Panels – Primary Equipment Impact - Outdoor Circuit Breaker

Sketch 3

Relay Panels – Primary Equipment Impact - Earth Switch

Sketch 4

Relay Panels – Primary Equipment Impact - Power Transformer

Sketch 5

Tap Change Control Panel – Primary Equipment Impact - Transformer

Sketch 6

Relay Panels – Equipment/Functions - Auto Reclose Function

Sketch 7 IEC61850 Substation Bus Sketch 8 Panel 1, Table 4 Front Panel Layout

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By Period Contract

Sketch 9 Panel 2, Table 5 Front Panel Layout Sketch 10 Panel 3, Table 6 Front Panel Layout Sketch 11 Panel 4, Table 7 Front Panel Layout Sketch 12 Panel 5, Table 8 Front Panel Layout Sketch 13 Panel 6, Table 9 Front Panel Layout Sketch 14 Panel 7, Table 10 Front Panel Layout Sketch 15 Panel 8, Table 11 Front Panel Layout Sketch 16 Panel 9, Table 12 Front Panel Layout Sketch 17 Panel 12, Table 15 Front Panel Layout Sketch 18 Panel 13, Table 16 Front Panel Layout Sketch 19 Panel 14, Table 17 Front Panel Layout Sketch 20 Earthing Link Structure

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REF – Draft 3 1 August 2010 PEE STANDARD NO : PEE138

CONSTRUCTION OF HIGH VOLTAGE SUBSTATION BY PERIOD CONTRACT




CONSTRUCTION OF HIGH VOLTAGE SUBSTATIONS BY PERIOD CONTRACT

INTRODUCTION 1. INTRODUCTION

This specification covers the design, manufacture, factory testing, supply, delivery, off-loading, installation, after-installation testing and possibly commissioning of outdoor high voltage substation (132 kV or 66 kV) bays. The outdoor bay(s) is associated with indoor protection and control equipment (supply and install) and MV switchgear (install only) forming part of the Contract. The Contractor shall be responsible for the complete substation or extension, including incorporation into the Municipality’s SCADA system, to the point where it could be safely energised. Drawings The contract also covers the preparation and supply of all drawings required for the effective and complete maintenance of the new works by the Employer’s staff. The drawings shall, inter alia, include foundation and support structure drawings, earth mat layout, yard layout, exact position of all installed cables (power and other) and all schematic and control drawings. IEC61850 substation bus and SCADA Electrical equipment (indoor and outdoor) shall be fitted for remote indication and control purposes (SCADA). The successful tenderer shall provide and install an IEC61850 substation bus. All equipment required to serve information to this bus or subscribed to information on the bus, shall be connected to the bus by the Contractor. The Contractor shall supply and install all hardware, firmware and software required to enable this.

2. DEFINITIONS

Major faults: Faults discovered during the commissioning process carried out by a third party (the commissioning contractor) which fall into one of the following categories: Faults falling outside the field of expertise of the commissioning contractor; Faults that will take in excess of four man hours to rectify. Minor faults: Faults not falling into the category of major faults.

3. REFERENCES

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3.1 Conditions of Contract

SAACE General Conditions of Contract PEE Special Conditions of Contract associated with the SAACE Conditions

3.2 Standards and Codes of Practice

Title Std CoP Rev. Rev. Date Laying of single core cables – trefoil 2.2 0 1 July 1991

Cable Stripping Instruction 2.5 1 12 Jan 2001

Joint Instruction Plumbing Method 2.23 1 12 Jan 2001

Departmental Standard Jointing Instructions 11 kV End Box

2.18 1 18 Jan 2001

MV Liquid neutral Earthing Resistors 3.6 0 13 Sep 2001

Burdens for MV Electromagnetic VT’s 3.7 3 16 Oct 2003

The small wiring of Transmission Equipment and Installations

9.1 D0 26 Apr 2005

Common Rules 10.1 3 15 Apr 2001

Protection Design Guidelines by E. Van Straten / P. Gerber (called PDG in rest of text)

9

Protection and Auxiliary Relays 100 6 5 Nov 2009

SCADA Interface Requirements 101 21 5 Nov 2009

Power Transformers 102 8 1 Sep 1997

Outdoor-Type Current Transformers 105 2 12 Feb 2001

Indoor Control Panels 113 7 5 Nov 2009

Outdoor-type Surge Arrestors 114 1 24 Jan 2001

Outdoor Disconnectors 122 D3 5 Nov 2009

Support Structures in High Voltage Outdoor Substation Yards

123

D2 5 Nov 2009

Tubular Aluminium Busbars 124 D2 8 Aug 2001

Earthing of Major Substations Built as Turnkey Projects

125

D1 8 Jan 2001

Trenching, Backfilling and Foundations for Outdoor Electrical Equipment

126

D1 13 Dec 2001

SCADA: Contractor’s Responsibilities on Turnkey Projects

127

D1 8 Jan 2001

Outdoor Circuit Breakers 128 D1 9 Jan 2001

Outdoor-Type Marshalling Boxes 129 D2 27 Mar 2007

Battery Tripping Unit 131 D1 4 Jan 2001

Bolts and Nuts SABS 135 Galvanising SABS 763 Structural Steel SANS 1431

CONTRACTUAL 4. APPOINTMENT SEQUENCE

Once a Contractor has been selected as the preferred Contractor for the next 3 years, appointments for individual Projects will be handled in the following way: The Employer shall identify and define the scope of a new project/appointment; The Employer shall develop a Single Line Diagram and a Protection Block

Diagram for the work to be done; The Employer shall inform the Contractor of his intention to launch a new Project;

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A meeting (will be referred to as the Launching Meeting) shall be scheduled between the Employer and the Contractor at which the scope of the project shall be communicated to the Contractor, both on site and by referring to previously prepared drawings.

The Contractor shall compile a preliminary cost estimate of the work and confirms that he understands the definition of the Project. (Preliminary because the final trenching lengths, cable quantities, etc. will not be available at this stage.) It shall be the Contractor’s responsibility to verify that rates exist for all work to be carried out under the specific Project.

Rates shall be negotiated (between the Contractor and the Employer) in respect of work not covered by the rates in Part C2.2.

The Employer shall appoint the Contractor in writing for the Project. The Contractor shall provide the Employer with the required surety amount in

respect of the applicable appointment. Should the Contractor require further information during the design stage, he shall deal directly with the Business Unit’s drawings office for such detail. It might be possible that certain information is not available, in which case the Contractor shall visit the site to obtain the required information. This “meeting” shall be referred to as the “Design Meeting”. There could be more than 1 Design Meeting per Project.

The Contractor shall design the project and submit drawings to the Employer for approval.

A Drawing Meeting shall be held to discuss the design drawings. The Contractor shall affect the required changes and the Employer shall approve

the drawings. 5. TIME FOR COMPLETION

A Time for Completion shall be negotiated with the Contractor prior to each appointment for new work. The surety bond, retention and maintenance period will be handled independently for each separate appointment or Project.

6. VARIATION OF CONTRACT PRICE

This clause does not deal with Rate of Exchange or “CPA based on SEIFSA indices” variations. It deals with price variations based on final quantities. The general principle is that the Contractor shall be paid for final quantities used or installed. 6.1 TRENCHING AND BACKFILLING OF CABLE TRENCHES

Stock bricks shall be placed over all MV cables laid directly into the ground. (Hence the rate for stock bricks under backfilling.)

6.2 BACKFILLING EXCAVATIONS / IMPORTED MATERIAL The price of backfilling shall cover backfilling by using local excavated material or imported material. It excludes the cost of the imported material itself which shall be made in accordance with Item 7.3.

7. CONTRACT PRICE ADJUSTMENT (CPA)

Only changes underwritten or covered by SEIFSA will be allowed. These need not necessarily be only those covered by the standard SEIFSA publication, so long as SEIFSA “supports” the relevant changes.

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All rates in Part C2.2 shall be subject to escalation formula to allow for the use of those prices for a period of 3 years. In the necessary columns in this Part, tenderers shall state, by using numbers, which escalation formula will apply for each rate. Tenderers shall, as part of their offer, submit all escalation formula in table format. The formula shall be numbered to allow easier reference to the rates in Part C2.2. The base prices for tender purposes shall be that listed by SEIFSA for the month published in the Project Specification.

8. RATES OF EXCHANGE (ROE)

Tenderers are to use the median of the rate of exchange on the date stated in the Project Specification as supplied by Standard Bank to determine price submissions related to imported equipment. Goods imported from European Community Countries shall be priced on the Euro currency and not in the currency of the individual country.

9. CPA AND ROE NOT SUBJECT TO RETENTION

Claims for Contract Price Adjustment and Rate of Exchange shall not be subject to retention.

10. SCHEDULE OF RATES (PART C2.2) The intention is that the list of rates in Part C2.2 be sufficiently complete to cover most scenario’s of HV substation and related (protection and control) work. Tenderers shall not be allowed to add items to the list in Part C2.2. Relay/control panels have been broken down into a basic panel (see table 1, PEE Std 138) plus additional items. The additional items have been listed under 3 categories:

The impact of primary equipment (See sketches 1 to 4 of PEE Std 138); The impact of additional equipment/functions (Table 2 of PEE Std 138) and; The impact of additional relays (Table 3 of PEE Std 138)

The basic panel + certain combinations of additional items were subsequently grouped into the most often used scenario’s (for standard relay panels 1 to 14 (panels 10 & 11 do not exist), see tables 4 to 17 (tables 13 & 14 do not exist) of PEE Std 138). Sketches 15 to 26 of PEE Std 138 covers the panel front layout of standard panels 1 to 14. It is important to ensure that the cost of the additional items used (building blocks) in the grouping are added to obtain the price of the group item. E.g. if transformer relay panel type x is made up of 10 building blocks, the cost of the panel should be the sum of the rates of the 10 building blocks. The cost of all work associated with a building block, shall be inclusive in the cost of that building block. E.g. the cost of an Auto Reclose (ARC) function shall also include the cost of the associated panel wiring and all other related equipment.

10.1 Supply Rate

The “SUPPLY RATE”-column is used by default for items that cannot be split into supply and install categories. Where the install column has been blanked out, please ignore the word “SUPPLY” in the rates column;

10.2 Termination of auxiliary cables

The “termination” of auxiliary cables include the following tasks: The termination of the multi-core cable onto the gland plate of equipment

(including cables glands and possible other miscelaneous equipment AND;

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Routing of individual cores via wiring trunking provided for that purpose plus termination of the cores onto terminals;

10.3 Time related P&G’s

This daily amount shall only be payable for the actual days worked up to “Time of Completion” of the works tendered or up to “Taking over”, whichever comes first.

10.4 Steel Support Structures - Item No 9 Based on experience gained on previous contracts, Contractors requested that steel support structures be split in the 3 categories indicated. Although the steel price (in tonnes) should remain the same for the 3 categories, Contractors will likely need cranes to assist with the erection of items 9.2 and 9.3. It is similarly unlikely that only a crane truck could be used for the erection of item 9.3.

10.5 Compact outdoor switchgear – CT (Item 13.14) The CT shall have 5 cores – 2 x class TPS 3200/2400/2000/1200/800/400/1 Vkp =

1600V 2 x class TPS 1200/1 Vkp = 1200V 1 x 15 VA 10P10 3200/2400/2000/1200/800/400/1

10.6 Impact of Primary Equipment (Part C2.2 – Items 24.2 to 24.5) All cost associated with cabling from the yard to the control panel will be paid for under other items. The cost here only needs to cover the installation of hardware, e.g. the circuit breaker control switch and then channelling of the loose wires from where a multi-core cable has been terminated on the control panel, via trunking, to the IED or other equipment. It also need to cover the wiring required (where applicable) between equipment in the control panel, e.g. from the output contact of a Master Trip Relay to the binary input of an IED.

10.7 Breaker Fail - Item 24.20 This functionality will reside in one of the existing relays on the panel. The cost here should only be that of the link and the associated wiring.

11. EMPLOYER'S SPECIFIC REQUIREMENTS IN THE ANNEXURES OF PART T2 OF INVITATION TO TENDER FORMS PART OF THIS SPECIFICATION

The detail listed under "Requirement" in the Annexures of Part T2 of this Invitation to Tender, form part of the Contract Specification and shall in all respects be interpreted as such. For example, where the Conditions of Contract refer to the Contract Specification, the "Requirements" columns in Part T2 shall be understood to be part of the Contract Specification.

12. APPOINTMENT TO COVER ALL WORK

When the scope of a new project is communicated to the Contractor at the Launching Meeting (see clause 4), it shall always be understood by the Contractor that the appointment shall cover all work required for the successful operation and integration of the extension or the new Project. Should work be required that involves rates (for either equipment or labour) not covered by Part C2.2, it does not mean that such equipment does not have to be supplied and installed under the appointment. New rates shall be negotiated for such items.

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The end result of every appointment shall always be a complete project, (including SCADA ) that would be ready for energising.

GENERAL DESIGN CRITERIA 13. PARTICULARS OF DISTRIBUTION SYSTEM

The nominal system voltages are

HV : 132kV and, occasionally, 66 kV MV: Mostly 11 kV, but sometimes 22 kV.

See PEE Code of Practice No. 10.1 for other details such as phase sequence, earthing and fault levels.

14. MINIMUM REQUIREMENTS

Specifications in this Invitation to Tender are meant to specify minimum acceptable standards for situations where it may be possible to have less stringent specifications. The contractor’s design team shall take full professional responsibility for the design of the extension. It is therefore important that they verify specifications before final designs and where these are in their view, insufficient, inform the Engineer accordingly and decide on acceptable design criteria.

15. DESIGN AND LAYOUT OF EQUIPMENT TO TAKE LEGISLATION INTO ACCOUNT

The contractor shall ensure that the design and layout of the equipment to be supplied and / or installed under this contract is such that, in all conditions, it complies fully with the Regulations promulgated in terms of the Occupational Health and Safety Act of 1994 and the latest amendments. Where equipment installed under this contract is to be positioned in the proximity of existing equipment, structures or plant, the contractor shall establish beyond any doubt that the said Regulations shall not be contravened by virtue of this proximity during the erection and testing periods and in the final operating conditions. Any queries in this regard must be submitted, in writing, to the Engineer.

16. PHASE SEPARATION AND EQUIPMENT SPACING

In the case of an extension to an existing substation, the space between phases in the outdoor yard shall be determined by the existing busbars, (unless these do not meet PEE Code of Practice 10.1). The new busbars shall have identical phase spacing. Equipment shall be spaced to match the layout of the existing bays. In the case of a new substation, the phase spacing shall be determined by the disconnectors as outlined in PEE Standard No 122.

17. ATMOSPHERIC AND ENVIRONMENTAL CONDITIONS

The entire installation and every component thereof shall be designed, manufactured and installed for long and trouble-free operation under the atmospheric and environmental conditions outlined in PEE Code of Practice 10.1. Specific attention must be given to the wind speed / pressure.

18. SAFETY FACTORS AND OTHER PRINCIPLES APPLICABLE TO MECHANICAL

STRENGTH CALCULATIONS

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Outdoor electrical equipment, its support structures and foundations shall, as a minimum standard, be designed based on the safety and other factors outlined in PEE Code of Practice 10.1.

19. DESIGN TEAM AND PROJECT MANAGER

Designs, drawings, etc, shall be checked, approved and signed by ECSA registered professional engineers with at least two years relevant experience following registration. The Employer's minimum requirements for professional staff shall include:

A Professional Engineer in electrical engineering (heavy current); A Professional Engineer in structural engineering. The project manager assigned to this project shall be approved by the employer.

20. DIMENSIONS ON EMPLOYER’S DRAWINGS TO BE VERIFIED

The Contractor shall verify dimensions on PEM drawings issued by the Client’s Drawing Office BEFORE designing support structures and foundations.

21. DRAWINGS The drawings referred to in the scope of this specification shall be prepared and approved by the Employer prior to manufacture and construction. Drawings shall be categorised as follows with the categories and revisions clearly indicated on drawings: Draft (There could be multiple draft revisions); Construction (When a draft has been approved for construction); As-built; As-commissioned. 21.1 Submission of First Set Of Drawings for Comment

The successful tenderer shall not submit any drawings whatsoever, before a complete set of drawings for all equipment to be supplied and relevant existing equipment has been produced, checked and cross-referenced. He shall make sure that ALL circuits, page referrals, cross references, item numbers (according to the item list), drawing numbers, page numbers, revision numbers and ferrule numbers are correct. The successful tenderer’s project manager shall be responsible for the above. Once he is satisfied that all the above has been checked in fine detail, the drawings shall be submitted to the Employer for comment. Tenderers shall allow in their submission for at least one visit to Port Elizabeth for the purpose of discussing drawings.

22. SELECTION OF SURGE ARRESTERS

Surge arresters shall be selected in accordance with Draft PEE Code of Practice No. 10.1.

23. SOIL TYPE

For quotation purposes, the soil shall be considered hand-pickable and allowing a bearing pressure of 150 kPa. The slope is to be considered 1% in all directions. The Contractor, as the designer, shall verify the above on site before final designs are conducted.

24. EARTH MAT

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Where an earth mat exists, the Contractor shall extend the mat if relevant and add outdoor earth connections to the earth mat in accordance with PEE Standard 125. The Contractor shall verify the following criteria theoretically for the new extended mat , i.e. the existing mat + the new section using the actual earth resistivity values he obtained from site: Earth resistance; Step Voltage and; Touch Voltage.

Should any of the above criteria not comply with IEEE80 (See PEE Standard 125), the mat shall be extended until the criteria is met. In the case of a new substation, the Contractor shall design the new earth mat to meet IEEE80 criteria. The following design criteria shall be used as scenario 1 for verifying the above: Earth fault current : 20 kA Fault clearance time : 1 sec Step : 1 m Weight of operator : 70 kg Scenorio 2+ Reduce the above one by one in the sequence below to the minimum values indicated: Earth fault current : 15 kA Fault clearance time : 150 ms Step : 0.75 m Weight of operator : 70 kg

25. PROTECTION AND CONTROL

The protection philosophy shall be made available to the Contractor prior to each appointment. Designs shall reflect the requirements of CoP 9.1 and the Protection Design Guidelines.

26. IEC61850 SUBSTATION BUS

26.1 Introduction

See Sketch 7 attached to this standard, for the basic concept.

26.2 Date Stamping

Events shall be date stamped. A substation installed GPS system for time synchronising is considered unnecessary at this stage. However, the bus shall be used to synchronise the time of all equipment connected to the bus.

26.2 Speed

The speed of the bus and all related and /or associated equipment shall be minimum 100 Mbits / second. Preference may be given to equipment offering significantly improved (more than specified above) speed.

26.3 Communication medium

Optical fibre shall be used. The Contractor shall select a fibre type to compliment his design best.

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26.4 Hardware

The following hardware shall be supplied by the Contractor: 26.4.1 HMI

The human-man interface shall be in the form of a touch screen industrial grade computer suitable for the robust environment it will be used in. The HMI shall be housed in a cabinet also to be supplied by the Contractor. The height of the HMI shall be such that it could be operated by an individual sitting on a chair in front of the HMI. The display of the substation network on the HMI screen shall be in the form of a live mimic allowing the operator to see the entire substation network. It shall be possible to zoom into portions of the network as required. The mimic shall

Indicate the status of all movable primary substation equipment

(e.g. circuit breakers, isolators, earth switches). Have control blocks for switching / changing the status of primary

equipment; Reflect the value of relevant analogue inputs (current, voltage and

tap positions);

Indicate a warning should there be any alarms. (All alarms associated with a bay could be paralleled to a single warning for that bay.)

26.4.2 Gateway + Configuration Tool

It is possible that some live substations, that need to be extended by a bay or more under this contract, might have been equipped already with an ABB RTU 560C. It may not be cost efficient to replace an existing RTU with a new gateway, should one be able to reasonably easy modify it (e.g. by installing new cards) to suit the revised needs. Tenderers shall therefore allow for dealings with ABB, in case the above situation arises. It is also assumed that the configuration tool will be that supplied by ABB for use with this RTU/Gateway – hence the reason for items 25.13 to 25.19 in the Bill (Part C2.2). Tenders will be evaluated using items 25.20 to 25.26. However, tenderers not providing reasonable prices against items 25.13 to 25.19. may be disqualified on this basis. For new projects, Contractors will likely be allowed to use their own gateway, providing communication between such gateway and the master station in the Control Centre, is accommodated by the Master Station and non-proprietary protocol is used.

26.4.3 Switches It is assumed that 19 –port switches will be used (16 IED’s + 3 backbone). However, should tenderers decide to use a different size

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switch as standard, it shall not be seen as a deviation to specification provided that the “new standard size” is clearly communicated in the tender submission. Switches shall be installed in cabinets also to be supplied and installed by the Contractor. At this stage it is not regarded necessary to connect switches in a ring. However, with reference to Sketch 7 each “outer” switch shall have one spare port.

26.5 Firmware and software The Contractor shall supply and install or firmware and software to make the substation bus fully functional. Where licences are applicable, the cost of that shall be included in Part C2.2.

26.6 Engineering Access via the IEC61850 Substation Bus

Each substation has communication to the remote control centre by either telephone lines, copper pilots or optical fibre (single mode). Tenderers shall make a proposal in their submission of how to establish remote engineering access to IED’s.

27. DESIGN CALCULATIONS TO BE MADE AVAILABLE UPON REQUEST

Design calculations shall be available to back-up the supply of any supporting structures and foundations. Although the designs need not be unique for this specific application, they shall prove that the structures/foundations are of sufficient strength to carry the maximum expected load for this application. The calculations shall be made available at the request of the Engineer.

28. PROGRESS REPORTS

For the time period between the appointment of the successful tenderer and commencement of erection on site, monthly progress reports shall be submitted to update the Employer on progress. The reports shall be submitted by the working day nearest to the 15 of each month and shall cover progress up to the end of the preceding month.

EQUIPMENT TO BE DESIGNED, MANUFACTURED AND SUPPLIED TO PEE STANDARDS 29. FOUNDATIONS

Foundations/footings/plinths shall be designed and installed for all equipment to be erected outside, whether via supporting structures (e.g. CTs) or direct (e.g. power transformers). Design and construction shall be to Draft PEE Standard No. 126.

30. SUPPORTING STRUCTURES

The design, construction and erection of supporting structures shall be done to Draft PEE Standard No 123.

31. OUTDOOR TYPE DISCONNECTOR

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Outdoor disconnectors shall comply in all respects with Draft PEE Standard No 122. Detailed requirements and other deviations from Standard 122 are also listed in Schedule 7, pages Sch7.b1 – Sch7.b8. All disconnectors and earth switches shall be motorised using DC supply from the Relay/Control panel controlling that bay.

32. CIRCUIT BREAKER

Three-phase gang-operated outdoor circuit breakers shall comply in all respects with PEE Standard No 128. Detailed requirements and other deviations from Standard 128 are listed in Schedule 7, pages Sch7.a1 – Sch7.a8. The design shall allow for manual operation of the mechanism. I.e. – slow opening and closing.

33. INTERLOCKING The required interlocking principles are displayed in sketches 1 to 11 of PEE Standard 122. Although these drawings reflect interlocking based on mechanical methods, the principle prevails. Interlocking between circuit breakers, disconnectors and earth switches shall be created in 2 ways: By electrical interlocking; By magnetic pin. Should disconnectors and earth switches be operated in the “normal” way by motor, method 2 above shall automatically be by-passed or de-activated. Should the disconnectors and earth switches be operated by hand, a micro switch operated by the handle shall activate interlocking method 2 above.

34. OUTDOOR TYPE CURRENT TRANSFORMERS

CT’s shall be supplied in accordance with PEE Standard No 105. Clauses 1.2, 3,7 and 3.8 of this Standard are not applicable to this contract. The winding ratios and other specific detail shall be as listed in Schedule 7, pages Sch7.c1 - Sch7.c14.

35. SURGE ARRESTERS

If lightning arrestors are required, the arresters selected in accordance with Clause 22 above, shall be supplied in accordance with PEE Standard No 114 with the following exceptions: Clause 4.1 is not applicable; Clause 4.3: Housing in Silicon Rubber Detailed requirements and other deviations from Standard 114 are listed in Schedule 7 (pink), pages Sch7.g1 – Sch7.g8.

36. HV BUSBARS

Straight busbar runs with no change in phase spacing shall be built using tubular bars. Flexible bars (conductor) shall be used in all other positions. Where flexible bars are used, only Bull or Centipede conductor shall be used.

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Where tubular bars are proposed, busbars shall be designed and installed in accordance with Draft PEE Standard No 124. In the case of flexible bars, Standard No 124 shall be applicable where relevant. Post insulators, complete with support structures and foundations, shall be used to support the busbars where bars are too long for self-support.

37. POWER TRANSFORMERS

Power Transformers shall be purchased under a separate Contract. Its associated Remote Tap Change Control Panels (RTCCP’s) shall be supplied under this contract. The supplier of the transformers shall deliver the transformers to site, mount them onto the previously prepared plinths (done under this Contract) and fully assemble them including filling them with oil. This contract allows for the supply, installation and commissioning of all control, auxiliary and secondary cabling required between the transformer and the control room and to individual equipment in the control room (e.g. Relay/Control Panel and RTCCP).

The install rate of the transformers (items 16.1 and 17.1) shall only apply where it may be necessary to move a used transformer from one substation to the other. This will seldomly (if ever) be required. In such case the cranes and low bed trucks shall be paid for under miscellaneous items. 37.1 Neutral Links

A link structure in line with that indicated within the dotted line of Sketch 20 (as attached) shall be supplied and installed under this Contract. The bare copper busbar and links shall be mounted via insulators on a galvanised steel framework. The size of the busbar shall be based on either earth fault current (short time) when the NER is out of service (see earth mat design for detail.) or with the NER in service (2000 A for 30 seconds), whichever scenario is worse. The insulators shall be designed for maximum voltage conditions, i.e. either 2000A x (Earth mat resistance + NER resistance) for 30 seconds, or maximum earth fault current without the NER (see earth mat design) x Earth mate resistance for short time. The links shall be knife or similar that can be operated by link stick and that would be similar to those found on MV bare overhead distribution systems.

38. EARTHING

The mat designed under clause 24 shall be installed in accordance with Draft PEE Standard No 125.

39. CONTROL PANELS (EXCLUDING REMOTE TAP CHANGE CONTROL PANEL WHICH IS

COVERED BY THE POWER TRANSFORMER SPECIFICATION)

Where control panels are called for, the panel(s) shall be manufactured and equipped in accordance with PEE Standard No 113 and installed by the contractor. Clauses 1(b) and 3.4.7 are not relevant to this contract. Specific requirements are listed in Schedule 7 (pink), pages Sch7.d1 – Sch7.d2. 39.1 Panel Wiring

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Panels shall be wired to Code of Practice 9.1. AC and DC supplies shall be to PDG Rev 9. 40. RELAYS

This clause shall be read in conjunction with clause 26 (IEC61850 Substation Bus). Details of the relays, which are to be supplied in accordance with PEE Standard No 100, are listed in Schedule 7 (pink), pages Sch7.e1 – Sch7.e8. Only numerical relays shall be supplied. Electro-mechanical relays shall only be considered if a numeric equivalent is either not available or does not make sense. Single relays with integrated relay functions are not acceptable. Each relay function shall be provided by a separate loose standing module. The only exceptions to this guideline would be Overcurrent and earth fault functionalities plus the various types of these

functionalties, e..g instantaneous overcurrent, sensitive earth fault, IDMTL earth fault could be combined into 1 relay;

Transformer differential protection plus restricted earth fault for the 2 windings could

be incorporated into one relay. At least one relay on each panel shall be capable of pre- and post fault recordings.

41. AUXILIARY CABLES

A minimum of 2 spare cores shall be allowed between each unique start and end combination. Four (4) spare cores shall be allowed between the yard marshalling kiosk and the relay panel;

Auxiliary cables shall be supplied by the successful tenderer. CT cabling between the outdoor yard and the control room shall allow for 4 wires in

respect of each core on each set of CT ‘s. I.e. ratio selection and the formation of the star point shall be done in the outdoor marshalling kiosk.

42. OUTDOOR MARSHALLING BOXES

If outdoor marshalling boxes are called for, the same shall be designed and installed in accordance with Draft PEE Standard No 129.

43. POWER CABLES (12 & 24 kV)

The successful tenderer shall trench and lay all single core power cables between the power transformer and the MV incomer panel in the control room in accordance with PEE Std No 126 and PEE Code of Practice 2.2. Tenderers shall quote provisional prices* for: The termination of the cables on the transformer (compound boxes) and the switchgear; The supply of the cable.

* Provisional in the sense that the Employer may opt to do these task(s) using its own material and / or labour.

44. MV INDOOR METAL-CLAD SWITCHGEAR

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MV switchgear shall be purchased under a separate contract. Tenderers shall supply rates for the installation of the most often used panels as listed in Part C2.2. The Contractor (under this Contract) shall be responsible for adding all IED’s supplied under the switchgear Contract to the IEC61850 substation bus.

45. BATTERY TRIPPING UNIT

If a battery tripping unit is called for, the same shall be supplied to PEE Standard No 131. Detailed requirements shall be as listed in Part T2.2. The BTU shall be wired up with a DC distribution board in the control room. If a BTU is not required, the existing BTU shall be used. The existing BTU has been cabled to a DC Distribution Board on the control room’s wall, from where the Contractor shall cable all required DC supply. All connections, cabling, etc, required between the DB and the tap-changer panel, the 132 kV control panel, etc, are to be supplied and installed by the contractor. All such material shall be supplied in accordance with the relevant SABS standards and Codes of Practice.

46. NEUTRAL EARTHING RESISTOR

If a neutral earthing resistor is called for, the same shall be supplied as specified in PEE Code of Practice 3.6. Regardless of the supplier of the NER, the successful tenderer shall Install a single 1 core 630mm2 Cu conductor between the transformer’s MV neutral

bushing and the existing NER. This entire link shall be insulated at the maximum voltage that will develop during fault conditions;

Terminate the above cable on both the MV transformer bushing as well as on the

NER’s link structure using Raychem or approved similar outdoor termination kits;

SUPPLIED BY OTHERS 47. EQUIPMENT SUPPLIED BY OTHERS

The Employer shall have the right to supply certain items for a Project via other channels of his choice. Should this happen, the equipment supplied by others shall clearly be communicated with the Contractor at the Launching meeting. Equipment that would, as a general rule, be supplied by others, include Power Transformers, MV switchgear and the SCADA RTU/Gateway. Should no reference be made to material supplied by others at the Launching Meeting, the Contractor shall assume that all material be supplied, installed and commissioned under this Contract.

BASE MATERIAL STANDARDS 48. ALUMINIUM AND ALUMINIUM ALLOYS

Aluminium shall be of the highest purity commercially obtainable. Aluminium and aluminium alloy castings shall be free from porosity.

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49. DISSIMILAR METALS

Dissimilar metals shall not be used in contact with each other. Bi-metal lugs or alternative methods approved by the Engineer shall be used to avoid contact of dissimilar metals.

MISCELLANEOUS 50. BOLTS AND NUTS

Bolts and nuts shall comply in all respects with the current edition of SABS 135. The bolts, nuts and washers used on outdoor galvanised steelwork shall be hot-dip galvanised. All bolts or studs shall project through the nuts but this projection shall not exceed 10 mm.

EQUIPMENT FINISHING 51. GALVANISING

All ferrous material shall be galvanised to SABS 763. A minimum thickness of 0,063 mm of zinc is required.

52. PAINTING

52.1 General

The material shall be completely shaped, cut, drilled, counter-sunk, welded, etc, before any paintwork commences.

52.2 Painting of Non-Galvanised Steelwork

Cubicles which contain wiring and other apparatus and are assembled in the works shall receive the external-finishing coat of paint in the works. Before painting, the parts shall be thoroughly cleaned by sand or shot-blasting or metal brushes and acid bathed to remove all traces of rust, scale or grease.

Immediately after cleaning, all rough surfaces shall be smoothed. The paint finish shall be powder coat at a minimum thickness of 80 microns. White chassis plates shall be supplied.

53. LABELS

All equipment to be supplied under this contract shall be provided with clear and concise descriptive labelling describing the function and the circuit number of the apparatus concerned. The labels shall be securely fixed to the equipment with screws or pop-rivets. In the case of open busbars, phase identification discs shall be fitted where practical, e.g. for strung busbars on the gantry beam below every string insulator set and for solid busbars on post insulator support pedestals. The discs shall be 150 mm in diameter and shall be coloured red, yellow or blue according to the applicable phase. The discs shall be easily readable from ground level. The indoor equipment, such as control cubicles, shall be labelled at the back and front, indicating the circuits controlled.

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Each fuse, link, protection relay, switch, control handle, control relay and indicator lamp shall be labelled to indicate its function. Complete particulars of instrument transformers and lightning arresters must be engraved or stamped on permanent weatherproof labels.

The manufacturer's details of switchgear, such as rating, type, serial number, etc, shall be engraved or stamped on a permanent weatherproof label.

FILLINGS AND ACCESSORIES 54. OIL

New oil shall be supplied on this contract for all equipment required to be oil-filled. Re-refined oil will not be accepted. Insulating oil shall comply with the current editions of SABS 555 and shall be passed through a filter before use. Lubricating oil shall comply with the current edition of SABS 053.

55. SF6 GAS

New sulphur hexafluoride (SF6) gas shall be supplied in all equipment designed for the use of SF6.

SF6 gas shall comply with the recommendations of IEC Publication No 376.

56. SPARES

All spare parts or materials containing electrical insulation shall be delivered in approved cases suitable for storing such parts over a considerable period of time without deterioration due to climatic conditions or other causes.

57. SPECIAL TOOLS

Where special tools (including computer software) are required for effecting adjustments, for dismantling purposes, for testing or for maintenance, a full kit of such tools shall be provided.

The cost of the special tools shall be deemed to have been included in the price of the device for which they are required, unless specially listed. These tools are not to be used during erection.

CONSTRUCTION 58. DRAWINGS TO BE SIGNED AND APPROVED BEFORE ANY CONSTRUCTION STARTS

The Engineer shall be furnished with three complete sets of all drawings required for the successful construction of the substation at least 25 working days before any construction starts. The drawings, which shall have been previously approved by the Engineer, shall be signed by the professional team covered in Clause 18.

59. LIVE SUBSTATION

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It is estimated that at least 50% of work shall be carried out in existing live substations. For projects where this would be the case, the supply to existing consumers shall be maintained at minimum risk to failure. The current network is such that, for any single fault on the system, supply to all consumers could be maintained. Although it may not be practical to maintain status quo during the construction phase, the work shall be so scheduled to reduce risk of failure to a minimum. It may also be necessary to erect temporary wood pole structures in the yard to allow easy and quick restore of supply where the risk has increased. Contractors shall be compensated for such work under contingencies (that is do not allow for the cost of labour and material in the contract price) if deemed necessary to do by the Employer, BUT the Contractor must be prepared for such work in terms of the availability of labour, wood poles, conductor, clamps and insulators. 59.1 Application for a shut down

Should the Contractor need to work on a live section of the network, he shall apply in writing for a shut down to the System Operations Engineer at least 1 week in advance.

60. LINE, LEVEL, SQUARENESS, PLUMB

The centre lines of all equipment to be erected shall be in line, level, perpendicular and plumb as applicable. Special attention shall be given to high items such as the lightning masts.

The top of all foundations/footings/plinths shall be at the same level unless a slope in the site surface is such that this is impractical. In such cases, as few as possible changes in level shall apply and the Engineer's approval in writing shall be obtained before implementation. The height of supporting structures shall be so designed that the centre line of the tubular busbars is level.

61. SITE MEETINGS

Consult the cover page of this Invitation to Tender to see whether the pre-tender site is compulsory or not. In case of a non-compulsary site meeting, tenderers are welcome to attend the pre tender site meeting if they wish. Tenderers shall build the cost of the following meetings into their prices: A compulsory site meeting shall be held fortnightly once construction has started. The

successful tenderers’ project manager shall attend at least, every second meeting.

The contractor shall be penalised with the cost of two site visits as tendered in Part C2.2, for each site visit he fails to attend. Penalties shall be deducted from payments due to the contractor.

62. SITE CONDITIONS

Water and a 230VAC supply should be available at most sites. 63. TRENCHING, CABLE LAYING AND BACKFILLING

Trenching, cable laying and backfilling shall be done in accordance with the relevant sections of Draft PEE Standard No 126.

of 31



All auxiliary and power cables shall be installed such that no bend is visible above ground, excavations shall be of such a depth to accommodate the bend beneath ground level. The cables shall be perfectly vertical between the equipment and ground. Auxiliary cables shall be supported by suitably sized galvanised cable tray between all outdoor equipment and ground.

64. MEDIUM VOLTAGE CABLE ENDS AND JOINTS

Medium voltage cable ends and joints shall be done in accordance with PEE Code of Practice No 2.18. The first joint and first end shall be witnessed and approved by the Engineer, after which he shall give permission in writing that the contractor can proceed with further ends/joints.

65. LEGISLATION AND OBLIGATIONS OF THE CONTRACTOR

65.1 Statutory Requirements

65.1.1 Occupational Health and Safety Act (OHS Act)

Any equipment, where applicable, offered against this Contract Specification and all work carried out shall conform to and comply with the relevant and applicable requirements of the OCCCUPATIONAL HEALTH AND SAFETY ACT (Act 85 of 1993) as amended, and/or the regulations framed there under, as amended. NB! See also Section 61.2 and 61.3.

65.1.1.1 Construction Regulations, 2003

Tenderers shall submit Health & Safety Plans with their tender and allow for all costs, which they might incur in setting-up, carrying out and administering a fully documented Health and Safety Plan. This Health & Safety Plan must be based on the risk associated with the work as detailed in this tender. The successful Tenderer (Contractor) will be required to set-up this Health and Safety Plan, using the Construction Regulations, 2003 of the Occupational Health and Safety Act as the Health and Safety Specification.

The Health and Safety Plan must include the preventative measures and systems, which will reduce the risk associated with personal injury as well as exposure to hazardous substances. This will include: a) Personal protection against falling objects. b) Personal protection against dust inhalation c) Personal protection due to damage of underground services d) Personal protection against electrical shock although the contractors will not be allowed to work on or in close proximity of live electrical apparatus e) Protection against noise f) Protection against vehicle movement g) Protection of hands and feet of working employees h) Other risks at the workplace

of 31



i) The provision of a fall protection plan when working in elevated position.

The tenders must indicate the following: 1. Training programs for employees including certification of such training on the specific risks. 2. The monetary provision made in the tender for:- a) Risks identification b) Health and Safety Training c) Personal protection equipment In addition the tenderers must indicate in detail their competency to carry out such work as specified in the tender in terms of the OHS Act including all previous personal experience associated with such work. Tenderers who do not comply with this requirement will not be considered. In addition tenderers with insufficient competencies in terms of the requirements of the Contractors Regulators of 2003 will also not be considered.

65.1.2 Compensation for Occupational Injuries and Diseases Act (COID

Act)

The contractor will be expected to familiarise himself/herself with and comply with all the relevant provisions of the COMPENSATION FOR OCCUPATIONAL INJURIES AND DISEASES ACT (Act 130 of 1993), as amended, and/or the regulations framed there under, Compensation Commissioner Registration Number (or that of any agents or sub-contractors) on an Acceptance of Appointment Form, which they will be obliged to sign on behalf of their business undertaking, before commencing work.

65.1.3 Unemployment Insurance Act (UIF)

The contractor will be expected to familiarise himself/herself with and comply with all the relevant provisions of the UNEMPLOYMENT INSURANCE ACT (Act 30 of 1996), as amended, and/or the regulations framed there under, as amended.

65.1.4 Labour Relations Act (LRA)

The contractor will be expected to familiarise himself/herself with the content of the LABOUR RELATIONS ACT (Act 66 of 1995), as amended, and/or regulations framed there under, as amended, and shall adhere to the Act and regulations in all respects.

65.1.5 Basic Conditions of Employment Act

The contractor will be expected to familiarise himself/herself with the content of the BASIC CONDITIONS OF EMPLOYMENT ACT (Act 75 of 1997), as amended, and/or the regulations framed there under, as amended, and shall comply with and adhere to the Act and regulations in all respects.

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NOTE : All costs which might be necessary to comply with these or any other statutory requirements not specifically mentioned, in any way, including the provision of any necessary / suitable equipment / materials shall be allowed for in the tender price and shall be at the cost and for the full account of the successful tenderer (contractor).

65.1.6 REGIONAL SERVICES COUNSIL (RSC) LEVIES.

All Contractors operating within the boundaries of the NMMM are liable to register with the Nelson Mandela Metro for the payment of RSC levies. Once registered the contractor will receive a registration certificate and a 900-account number. Depending on the scale of operation the Contractor will be liable to pay levies either monthly or annually to the Council, which will be specified on the registration certificate. The Contractor will receive a declaration form, which he/she is required to return with his/her payment to the Council. Non-registration will lead to Contractor payments being withheld till such registration is received by the NMMM. If RSC levies or consolidated billing account (water, rates, electricity) are in arrears payment will also be withheld till such accounts are up to date. This may result in a 4-day delay in payment.

65.2 EXTENT OF CONTRACTOR’S OBLIGATIONS

The Municipality and the Contractor agree, in terms of the provisions of Section 37(2) of the OCCUPATIONAL HEALTH AND SAFETY ACT, 1993 (Act 85 of 1993), herein after referred to as “the Act”, that the following arrangements and procedures shall apply between them to ensure compliance by the Contractor with the provisions of the Act, namely:- The contractor undertakes that the appropriate officials and employees of the Contractor will fully acquaint themselves with all relevant provisions of the Act and the regulations promulgated in terms of the Act. The Contractor undertakes that all relevant duties, obligations and prohibitions imposed in terms of the Act and regulations will be fully compiled with. The Contractor hereby accepts sole liability for such due compliance with the relevant duties, obligations and prohibitions imposed by the Act and regulations, and expressly absolves the Municipality from itself being obliged to comply with any of the aforesaid duties, obligations and prohibitions.

The Contractor agrees that any duly authorised officials of the Municipality shall be entitled (although not obliged) to take such steps as may be necessary to ensure that the Contractor has complied with his undertakings as set out more fully in paragraph (a) and (b) above, which steps may include, but will not be limited to, the right to inspect any appropriate site or premises occupied by the Contractor, or to inspect any appropriate records held by the Contractor. The Contractor shall be obliged to report to the Municipality any investigation, complaint or criminal charge, which may arise as a consequence of the provision of the Act and regulations, pursuant to work performed in terms of this Contract, and shall, on written demand, provide full details in writing, of such investigation, complaint or criminal charge.

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65.3 SAFETY CONDITIONS

65.3.1 General

All work undertaken by the Contractor and any agents or sub-contractors by him/her in terms of this Contract shall strictly comply with any relevant safety requirements called for in any Statutory requirements laid out in Clause 29.1 above. It is the responsibility of the Contractor to acquaint himself/herself with such requirements and to ensure that his/her work force are also aware of these requirements and comply with them at all times.

All statutory safety equipment that may be required shall be supplied by the Contractor and it shall be used by his/her workers who must be instructed in its proper use. The Contractor and any agents or sub-contractors shall not carry out any operating or work on Council plant or the electrical infrastructure.

65.3.2 Scaffolding/Lifting Equipment

The Contractor shall be responsible for the mechanical safety of ALL lifting equipment/ladders and scaffolding used in carrying out this Contract.

65.3.3 Competent Persons

The Contractor shall be required to ensure that all persons involved with lifting operations or working from elevated positions are registered with the Department of Labour as competent persons for the particular scope of work required of them. Any deviations from this requirement shall be reported to and discussed with the Project Manager/Engineer.

TESTING AND COMMISSIONING 66. TESTS

66.1 General

All testing shall be arranged to represent the working conditions as closely as possible.

The Council reserves the right to appoint a representative to inspect the equipment at any stage of the manufacture and to be present at any of the tests required. Such inspection shall not relieve the contractor of his responsibility for meeting all the requirements of the specification and it shall not prevent subsequent rejection if such material or equipment is later found to be defective. The contractor shall give at least one week's notice of the date on which the equipment will be ready for testing/factory inspection, in order that the Engineer may arrange for the presence of a witness, if deemed necessary. Copies of test certificates (in English) showing the results of all routine and type tests performed shall be supplied to the Council.

66.2 Type Tests

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The equipment shall be type tested in accordance with the latest edition of the relevant SABS Specification, BS Specification or IEC Recommendation with which it is required to comply.

66.3 Circuit Breakers

The operating characteristics of circuit breakers, which are dependent on the pressure/density of a gas for operation and/or insulation, shall be tested at the pressure/density that would normally cause a lockout.

66.4 Routine and Sample Tests

The equipment shall be tested as routine or by a sampling method in accordance with the latest edition of the relevant SABS Specification, BS Specification, or IEC Recommendation with which it is required to comply.

66.5 Site Testing

Site testing to ensure correct operation of the entire works shall be carried out. 67. FINAL COMMISSIONING

The Contractor will likely commission all projects. However, the Employer shall have the right to appoint a third party to commission a Project, in which case the following shall apply: The commissioning shall be witnessed by the Contractor. The contractor’s witness

shall be suitably qualified to witness and confirm all tests and commissioning that needs to be carried out.

The contractor shall make personnel available for the rectification of all major faults

discovered during this period.

The Contractor shall decide when the Works are fit for energising and shall take full responsibility for the decision.

MAINTENANCE PERIOD 68. FAULTS DURING MAINTENANCE

The nature of the service rendered by the Employer often makes it impractical to call the contractor out for repairs during the maintenance period. Where repairs are to be carried out immediately in order to restore the supply to consumers, the Employer will be doing the repairs and the related costs will be set off against the retention fees. Wherever practical, evidence shall be kept to prove such repairs.

Where faults do not affect supply to consumers, the contractor shall be called out for repairs. Failure to report to the Engineer by the end of the second working day following the fault will result in repairs being carried out by the Employer and costs being set off against retention fees.

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UPDATES

Rev Draft 3 Sections were changed to read Parts in line with

the new CIDB format of the Tender Suite. E.g. the old Section E (Prices) is Part C2.2 of the new tender suite.

ANNEXURE A

TABLE 1 Basic Panel

Equipment PEE

Standard/CoPDrwg and / or table Reference

Front access cabinet Std 113 AC supply PDG 9 Fig 1.2 DC Supply PDG 9 Fig. 1.1 Control & Indication Equipment

Instruments Ammeter Std 138 Table 2, F.1

Supervisory on/off control switch Std 138 Table 2, F.5 Protection

Relays IDMTL OCEF + Highset OCEF (24 binary inputs / 24 binary outputs)

Std 138 Table 3, R.4

Trip Isolating links x 3 1 x for HV main 1 x for HV back-up 1 x for Breaker fail

TABLE 2 IMPACT OF ADDITIONAL EQUIPMENT / FUNCTIONS ON BASIC PANEL

Equipment/

function Associated Equipment Hardware

other than panel wiring Served to IEC61850 bus via

bay controller Subscribed from IEC61850 bus

Further associated with primary equipment in sketches 1 to 6?

F.1 Ammeter Ammeter Selector Switch; Current Transducer

Current indication None No

F.2 Voltmeter

Voltmeter Selector Switch; Fuses (outdoor); MCB(in panel); Voltage Transducer; VT supply healthy relay;

Indication Voltage Indication; Alarms (binary) VT MCB Trip; VT supply Fail

None No

F.3 AC supply Double pole MCB’s; MCB trip alarm None No F.4 DC supply Double pole MCB’s; MCB trip alarm None No

F.5 Supervisory on/off switch

None Supervisory selector off alarm

None No

F.6 CB trip/N/close control Yes, sketch 2

F.7 Isolator open/close control

Yes, sketch 1

F.8 Earth Switch open / close control

Yes, sketch 3

F.9 ARC on/neutral/off control

On/off latching relay; ARC “on” lamp

ARC off alarm; ARC off status

None No

F.10 Summation CT (1+1 / 1) None None None No

TABLE 3 IMPACT OF ADDITIONAL RELAYS ON BASIC PANEL

Function CT Inputs Associated Equipment Served to IEC61850 bus Binary Inputs Binary Outputs

R.1

Transformer protection (Incl. HV REF, MV REF, Tx Diff + at least 5 Tx trips such as Buchholz, temp, etc.)

Primary phases (4 wires) Secondary phases (4 wires) Primary neutral (2 wires) Secondary neutral (2 wires)

PK 2 Test blocks: 2 x six way or 2 x four ways and 2 x two ways Isolating Links (over & above those contained in the standard panel 2 x for a second HV breaker (main & back-up) 4 x for 2 MV breakers (main & bu)

AlarmsProtection fail; Transformer protection operated

24 24

R.2

High Impedance Busbar Protection

Input 1 from associated bay (4 wires); Input 2 from another bay (4 wires); Input 3 from yet another bay (4 wires).

PK2 Test blocks: 3 x four way (2 for CT’s from external bays) External resistors Metrosil Isolating Links Nil (Assumed to always sit on the same panel as R.1 above)

AlarmsProtection fail; Busbar protection operated

6 6

R.3 Master trip Relay None MTR reset push button MTR operated (for close

interlocking) N/A 12

R.4

IDMTL OCEF & highset OCEF

4 wires from 10P10 CT PK2 Test blocks: 1 x 4 way Isolating Links 2 x for 1 HV breaker (main & bu) 1 x for breaker fail

AlarmsProtection operated; Protection failed

24 24

R.5 a

Feeder Diff Protection (fibre)

4 wires from CLX CT PK2 Test blocks: 1 x 4 way Other Relay for checking fibres Isolating Links 1 x for fdr diff protection (see PDG)

AlarmsProtection fail; Feeder protection operated; Protection fibre fail.

24 24

R.5 b

Feeder Diff Protection (copper)

4 wires from CLX CT PK2 Test blocks: 1 x 4 way Other Relay for checking pilots

AlarmsProtection fail ???; Feeder protection operated; Protection pilot fail.

6 6

Isolating Links1 x for fdr diff protection (see PDG)

R.6 Auxiliary Relay for multiplying contacts

None None None N/A 6

R.7 Inter-trip Receive Relay

AlarmsInterTrip Operated; Protection fail.

N/A 6

R.8 Inter-Trip Send Relay None Isolating Links1 pairs

N/A 6

R.9 Breaker Fail None Isolating Links1 pairs

None

TABLE 4 – STANDARD RELAY PANEL 1 Transformer Panel Type 1a (DBB) (See Protection Design guidelines and References Rev 9, Fig 2.2, P. 34) PEE Std 138

Table or Sketch No

Impact of primary equipment 2 x Isolators Sketch 1 2 x BB Isolators 2 x Earth Switches Sketch 3 1 x BB ES

1 x Tx ES 1 x Circuit Breaker Sketch 2 1 x Transformer Sketches 4 & 5

Relays 1 x R.1 Table 3 Transformer Protection 1 x R.3 Table 3 MTR

Equipment/Functions 1 x F.6 Table 2 CB Trip / Close control 2 x F.7 Table 2 Disconnector open / close control 2 x F.8 Table 2 Earth switch open / close control

+ Basic Panel!

TABLE 5 – STANDARD RELAY PANEL 2 Transformer Panel Type 1b (SBB) (See Protection Design guidelines and References Rev 9 Fig 2.2, p.34) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Isolator Sketch 1 1 x Earth Switch Sketch 3 1 x CB Sketch 2 1 x Transformer Sketch 4 Relays 1 x R.1 Table 3 Transformer Protection 1 R.3 Table 3 MTR Equipment/Functions 1 x F.6 Table 2 CB Trip / Close control 1 x F.7 Table 2 Disconnector open / close control 1 x F.8 Table 2 Earth switch open / close control

+ Basic Panel!

TABLE 6 – STANDARD RELAY PANEL 3

Transformer Panel Type 2a (SBB) (See Protection Design guidelines and References Rev 9 Fig 3.1, p.39) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Isolator Sketch 1 1 x Earth Switch Sketch 3 Relays 1 x R.1 Table 3 Transformer Protection 1 x R.2 Table 3 High Impedance Busbar Protection 1 x R.3 Table 3 MTR Equipment/Functions 1 x F.7 Table 2 Disconnector open / close control 1 x F.8 Table 2 Earth switch open / close control + Basic Panel!

TABLE 7 – STANDARD RELAY PANEL 4 Transformer Feeder Panel Type 1 (See Protection Design guidelines and References Rev 9 Fig 4.1, p.46) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Isolator Sketch 1 2 x Earth Switch Sketch 3 Relays 1 x R.1 Table 3 Trfr Protection 1 x R.3 Table 3 MTR 1 x R.5 Table 3 Feeder Diff 1 x R.7 Table 3 Inter-Trip Receive 1 x R.8 Table 3 Inter-Trip Send Other Functions 1 x F.7 Table 2 Iso open/close control 2 x F.8 Table 2 ES open / close control 1 x F.9 Table 2 ARC NB! Remove OCEF & Highset OCEF Relay from Std Panel. + Basic Panel!

TABLE 8 – STANDARD RELAY PANEL 5 Transformer Feeder Panel Type 2 (See Protection Design guidelines and References Rev 9 Fig 5.1, p.51) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Isolator Sketch 1 2 x Earth Switch Sketch 3 Relays 1 x R.1 Table 3 Trfr Protection 1 x R.3 Table 3 MTR 1 x R.5 Table 3 Feeder Diff 1 x R.8 Table 3 Inter-Trip Send Other Functions 1 x F.7 Table 2 Iso open/close control 2 x F.8 Table 2 ES open / close control 1 x F.9 Table 2 ARC 1 x F.10 Table 2 Summation CT + Basic Panel!

TABLE 9 – STANDARD RELAY PANEL 6 Feeder Protection Panel Type 1e(i) (DBB) (See Protection Design guidelines and References Rev 9 Fig 10.1, p.61) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Circuit Breaker Sketch 2 3 x Isolator Sketch 1 3 x Earth Switch Sketch 3 Relays 1 x R.3 Table 3 MTR 1 x R.5 Table 3 Feeder Diff 1 x R.9 Table 3 Breaker Fail Other Functions 1 x F.6 Table 2 CB trip / close control 3 x F.7 Table 2 Iso open/close control 2 x F.8 Table 2 ES open / close control 1 x F.9 Table 2 ARC

+ Basic Panel!

TABLE 10 – STANDARD RELAY PANEL 7 Feeder Protection Panel Type 1e(ii) (SBB) (See Protection Design guidelines and References Rev 9 Fig 10.1, p.61) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Circuit Breaker Sketch 2 2 x Isolator Sketch 1 3 x Earth Switch Sketch 3 Relays 1 x R.5 Table 3 Feeder Diff Other Functions 1 x F.6 Table 2 CB trip / close control 2 x F.7 Table 2 Iso open/close control 2 x F.8 Table 2 ES open / close control 1 x F.9 Table 2 ARC + Basic Panel!

Although Fig 10.1 also indicate a MTR and breaker fail functionality, it is assumed that single busbar substations would normally be associated with bus sections and therefore no full-on bus zone protection. As a result also no MTR and breaker fail functionality.

TABLE 11 – STANDARD RELAY PANEL 8 Feeder Protection Panel Type 1e(ii) (DBB) (See Protection Design guidelines and References Rev 9 Fig 4.1, p.46) End Remote from the Transformer PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Circuit Breaker Sketch 2 3 x Isolator Sketch 1 3 x Earth Switch Sketch 3 Relays 1 x R.3 Table 3 MTR 1 x R.5 Table 3 Feeder Diff 1 x R.7 Table 3 Inter-Trip Receive 1 x R.8 Table 3 Inter-trip Send Other Functions 1 x F.6 Table 2 CB trip / close control 3 x F.7 Table 2 Iso open/close control 3 x F.8 Table 2 ES open / close control

+ Basic Panel!

TABLE 12 – STANDARD RELAY PANEL 9

Feeder Protection Panel Type 1e(ii) (SBB) (See Protection Design guidelines and References Rev 9 Fig 4.1, p.46) Remote End from the Transformer PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Circuit Breaker Sketch 2 2 x Isolator Sketch 1 3 x Earth Switch Sketch 3 Relays 1 x R.3 Table 3 MTR 1 x R.5 Table 3 Feeder Diff 1 x R.7 Table 3 Inter-Trip Receive 1 x R.8 Table 3 Inter-Trip Send Other Functions 1 x F.6 Table 2 CB trip / close control 2 x F.7 Table 2 Iso open/close control 3 x F.8 Table 2 ES open / close control + Basic Panel! It is assumed that there would not be full bus zone protection on single busbar substations. As a result, no breaker fail functionality is available. No ARC because its transformer feeder protection (??? This statement may need some debate)

TABLE 15 – STANDARD RELAY PANEL 12 Feeder Protection Panel Type 3 (SBB) (See Protection Design guidelines and References Rev 9 Fig 12.1, p.61) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Circuit Breaker Sketch 2 2 x Isolator Sketch 1 3 x Earth Switch Sketch 3 Relays 1 x R.3 Table 3 MTR 1 x R.5 Table 3 Feeder Diff Other Functions 1 x F.6 Table 2 CB trip / close control 2 x F.7 Table 2 Iso open/close control 3 x F.8 Table 2 ES open / close control 1 x F.9 Table 2 ARC + Basic Panel! The MTR is suppose to be operated by the Busbar (Not Buszone) protection. PDG rev 4 indicates this. However, the busbar protection relay would normally sits on a transformer control panel with its own MTR and therefore a MTR on this feeder panel would normally not be required. If you remove the MTR from here, the panel becomes identical to earlier feeder panels. I decided to leave it in for the time being.

TABLE 16 – STANDARD RELAY PANEL 13 Bus Coupler / Bus Section Protection Panel Type 1a (See Protection Design guidelines and References Rev 9, Fig 13.1, p.67) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Circuit Breaker Sketch 2 2 x Isolator Sketch 1 2 x Earth Switch Sketch 3 Relays 1 x R.3 Table 3 MTR Other Functions 1 x F.6 Table 2 CB trip / close control 2 x F.7 Table 2 Iso open/close control 2 x F.8 Table 2 ES open / close control Typically used where full buszone protection is present. + Basic Panel!

TABLE 17 – STANDARD RELAY PANEL 14 Bus Coupler / Bus Section Protection Panel Type 1a (See Protection Design guidelines and References Rev 9, Fig 13.1, p.67) PEE Std 138

Table or Sketch No

Impact of Primary Equipment 1 x Circuit Breaker Sketch 2 2 x Isolator Sketch 1 2 x Earth Switch Sketch 3 Other Functions 1 x F.6 Table 2 CB trip / close control 2 x F.7 Table 2 Iso open/close control 2 x F.8 Table 2 ES open / close control Typically used where there is not full bus zone protection. + Basic Panel!

ANNEXURE B

Iso open status

Iso close status

CB from 1 other bay openIso open command

Iso close command

RELAY PANELS - PRIMARY EQUIPMENT IMPACTDISCONNECTOR

SKETCH 1

IED

Eth

erne

t

Associated equipment / functions (see table 1 - Relay /Control panel building blocks - Equipment / Functions):

1. F.7 - Isolator open/close control

IEC61850 Bus

Open

Open

Close

Close

M

Open / Close control

Open

OutdoorRelay/control Panel

SKETCH 2

OUTDOOR CIRCUIT BREAKERRELAY PANELS - PRIMARY EQUIPMENT IMPACT

Eth

ern

et

IED

Spring Discharged

CB Open

CB Close

SF6 Low

SF6 Lock-out

CB Open status

CB Close status

SF6 Low alarm

SF6 Lock-out alarm

TSpring Discharged alarm

CB Open Control

CB Close Control

TCS-M

TCS-BU

CB in "LOCAL" position

CB in "LOCAL" position

TCS -M Healthy

TCS - BU Healthy

Associated equipment / functions (see table 1 - Relay /Control panel building blocks - Equipment / Functions):

1. F6 - CB trip/close control

IEC61850 BusOutdoor Relay/Control Panel

External Bay1 MTR operated

External Bay2 MTR operated

Trip Circuit Supervision

MTR

CB closing allowed

MTR operated

ES open status

ES close status

Iso from 1 other bay openES open command

ES close command

SKETCH 3RELAY PANELS - PRIMARY EQUIPMENT IMPACT

EARTH SWITCH

Open

OpenIED Back-up Protection

Close

Close

M

Open / Close control Eth

erne

t

OpenAssociated equipment / functions (see table 1 - Relay /Control panel building blocks - Equipment / Functions):

1. F.8 - ES open/close control

Relay Panel

Outdoor

TAP CHANGE CONTROL PANEL - PRIMARY EQUIPMENT IMPACTPOWER TRANSFORMER

SKETCH 4

POWER TRANSFORMERRELAY PANEL PRIMARY EQUIPMENT IMPACT

SKETCH 5

Eth

ern

et

IED

Eth

ern

et

IED

Trips

Winding Temp Trip

Oil temp Trip

Buchholz Trip

Over Pressure Trip

Buchholz TC Trip

Parallel operational error

Voltage Regulating Relay Fail

High Circulating Current

Taps Not Complete

VT Supply Fail

AC Supply Fail

Taps Not Commenced

Alarms

Winding temp alarm

Oil Temp alarm

Tx Oil Level Alarm

TC Oil Level Alarm

Tx Buch Alarm

TC Buch/Pressure Alarm

Trip Annunciater

Alarm Annunciater

Auto Select

Manual Select

Tap RaiseTap Lower

Cooler Supply fail

Manual

Auto

Local (Tx Drive Mech)

Remote (Tx Drive Mech)

Supervisory Selector On

Supervisory Selector Off

Alarm Annunciater

IEC61850 BUS

Relay Panel

Outdoor

OutdoorRemote Tap Change Control Panel (RTCCP)

IEC61850 BUS

Tx "A" alarm

TC Drive Mech in "Local" position

Tx "B" alarm

Tap Position (via transducer)

SKETCH 6RELAY PANEL - EQUIPMENT / FUNCTIONS

AUTO RECLOSE (ARC)

Eth

erne

t

IED

NOnOff

ARC off alarm

ARC Off Status

ARC off control

ARC On Control

Control

ARC "on" lamp

On/off Relay

IEC61850 BUS

RELAY PANEL

Also see Table 2

SKETCH 7 - IEC61850 SUBSTATION BUS

Switch

Spare

HMIGateway

To ABB Master Station

Spare

IED IED IED

Switch

To next switch

Spare

Connection for remote engineering access

IED IED IED IED

Fed from SubstationA @ voltage x kV

12

34

5

6

78

Key exchange

1/3

Key exchange

5/7CaptiveCaptive CaptiveCaptive

CaptiveCaptive

9 10 11CaptiveCaptiveCaptive

12

18

14

1513

1916 17

Captive

CaptiveCaptiveCaptiveCaptive

Captive

Captive

Captive

Scenario Displayed:All CB's & isolators in closed position

Captive

Key exchange

4/6

Medium Voltage busbars

Sketch 8

Sketch 9


12

34

5

6

78

Key exchange

1/3

Key exchange

5/7 CaptiveCaptiveNon-captive Non-captive

Non-captiveNon-captive

9 10 11

Non-captive Non-captive Non-captive

12

13

16 17 18 19 15

14

Scenario Displayed:Just after all CB's have been opened

Captive

Captive

CaptiveCaptiveCaptive

Captive

Captive Captive

Captive

Key exchange

4/6


Sketch 9

Sketch 10


2

4 6

8

Key exchange

1/3

1

3

Key exchange

5/7

5

7

Captive in TransitCaptive in Transit (CiT)

9

1011

12

16

17 18

19

14

15

C

13

C

C

CC

C

C

C

C

C

Scenario Displayed:Key movement from CB's to isolators

C

CiTCiT

NC NC

NC

NC

NC

Key exchange

4/6


Sketch 10

Sketch 11


2

4 6

8

Key exchange

1/3

1

3

Key exchange

5/7

5

7

Captive in TransitCaptive in Transit

910 11

12NC

13

C

NC16

C17

C18

NC19

NC14

C15

Scenario displayed:First isolators opened;Once opened, their keys (which are captive while the isolatorsare closed) become free.

C

CC

CiTCiT

C

CC

CNC

Key exchange

4/6


Sketch 11

Sketch 12


4 6

Key exchange

1/3

1

3

Key exchange

5/7

5

7

Captive in TransitCaptive in Transit8 Captive in Transit

2 Captive in Transit

910 11

13

C

C15C

17C

18

NC1412

NC

NC16

NC19

Scenario Displayed:The Captive-in-Transit (CiT) keys are now moved to the second isolators associated with each CB.

C

CC

C NCC

C

C

Key exchange

4/6


Sketch 12

Sketch 13


4 6

Key exchange

1/3

1

3

Key exchange

5/7

5

7

Captive in TransitCaptive in Transit8 Captive in Transit2 Captive in Transit

910 11

13

NC

12NC

NC1617

15NC

14NC

NCNC

18NC19

Key exchange

4/6C C

C

C NC

C

Scenario displayed:The second isolator associated with each CB has now been opened;Opening of the isolators release keys required to close earth switchesnot directly mechanically linked to it.These (isolator) keys are moved to the earth switches.

C

C


Sketch 13

Sketch 14


Key exchange

1/3

1

3

Key exchange

5/7

5

7

8 Captive in Transit2 Captive in Transit

910 11

13C

12C

17C

16C

14C

15C

19C

18C

Key exchange

4

6

4/6

C

C

C

C

C

CiT

NCC

C

Scenario displayed:The earth switches are closed;Trfr No 2 isolator now ready to be opened.


Sketch 14

Substation Name Convention


SubstationA x kV Line Earth Switch

SubstationA x kV Line Isolator

Substation A x kV Circuit Breaker

Substation A x kV BB Isolator

Substation A x kV BB isolatorCB Earth Switch

Transformer No 3

Trfr No 3 x kV Busbar Isolator

Trfr No 3 x kV BB IsolatorTx ES

Transformer No 1

1

23

4

5

6

1

2

3

8

10

11

12

13

Substation A x kV Line Isolator CB Earth Switch

4

5

6

7

8

12 Bus Section 1 x kV BB Isolator ACB ES

Bus Section 1 x kV BB Isolator A

11 Bus Section 1 x kV CB

10 Bus Section 1 x kV BB Isolator BCB ES

9 Bus Section 1 x kV BB Isolator B


9

13

7

14

14

14 Bus Section 1 x kV BB Isolator ABB ES