presentation slide on the requirement of kt or ks as in-house workshop

8/8/2019 Presentation Slide on the Requirement of KT or KS as in-House Workshop

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Purpose of KT/KS

This is really a value added program for sharing knowledgebetween all participants of different segments mainly like EHV,MV (Switch-yard & sub-stn with Automation), EPC ,Electrical, HVAC, DG . If possible manufacturing/plant (DG,HT & LT panel) people from Production unit may also

participate for sharing their knowledge and exp mainly.


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As Sterling & Wilson Ltd is mainly started their business fromMEP segment and continuing to expand their business in differentsegment mainly like Manufacturing, EPC (Trunkey job for Processplant, Switch-yard & Sub-stn job of different voltage levelwith/without Automation) as of now and in future may enter intonew area like BOP, GIS also . So we should be ready to takechallenge for the same. For which new system like KT/KS willreally help us for achieving the target very easily and with greatconfidence.


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The values you value mostmay be those that are least visible

What makes the difference?

Know-how is based on learning and learning is based oncooperation ,communication and interaction within a teamand beyond.

Although our cultures values, and visions may differ, but thecustomers regard as an honest, thoughtful partner, one whois easy to cooperate with and always available whenever andwherever needed.


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Ask ourcustomers...

...customers who trust us. They know that wealways do our best and never give up,

whether our solutions are best ,based on ourprevious track-record and knowledge


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A simple solutionto a complex problem


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Financing Infrastructure

When you examine long-term earnings andsavings, you can see that investment and life-cyclecosts are two sides of the same coin.

An equally far-reaching question is whether the

investment will accomplish what you really need or merely what you ask for? Do we know yourneeds better than you do yourself? Are we thatpresumptuous? Far from it.

But we have the skill and know-how to ask in-

depth questions about your needs andrequirements.

What youreally need ?


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The reason we ask these questions is simply because we care.

Your most successful and competitive power system solutionwill be based on functional specifications, derived from mutualunderstanding and easy interaction with each other rathermaking a gap .


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The best solution at the lowest price is onlypossible if we all can work together right fromtender stage(BOQ preparation) to the final executionstage with close cooperation with customer

throughout the entire project, from the initialanalysis to energizing of the substation in everyrespective levels.Preparation of BOQ after reading the tender docthoroughly .

If any customer specific BOQ supplied, then plcompare with the prepared BOQ and the suppliedone.

A solution based onclose cooperation


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Preparation of BOQ after reading the tender doc thoroughly .

If any customer specific BOQ supplied, then pl compare withthe prepared BOQ and the supplied one.

Entire technical spec should study properly specially requiredsystem data, equipment/product data with supplied DRWG

mainly SLD, Section, GA & Plan layout.

Prepare a list of queries based on the observation done fromTS,BOQ and DRWG.


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Incoming lines in a switching station


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Transmission line


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SF6 Circuit Breaker


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Switch-yard

.


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Trafo bay with ACSR conductor connection bet equip


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Transformer bay with Al tube connection bet equip

to equip


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Control Room with Control & Relay panel


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Tendering stage requirement

To study the detail system data required for the specificproject e.g.

Fault current with duration

System voltage

Site location, geographical data including climate condition

Creepage distance reqd by the customer based on pollutionlevel

Bus-bar details spec

Equip spec details

Earthing spec

Battery voltage with required AH

Lightning and Lighting spec


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Bus Bar Scheme design

There are fourpossibilities for to selectbus-bar scheme, ifcustomer are not

specified. Single Bus system

Main & Transfer Bussystem

Double Bus system


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Sub- Stations (33/11 kV, 33/22kV and22/11kV

System ParametersParameter 33 kV 22kV 11kV

Nominal

System

Voltage

33 kV 22 kV 11 kV

Highest

system

voltage

36 kV 24 kV 12 kV

Frequency 50 Hz 50 Hz 50 Hz

Lightning

impulse

withstand

voltage

170 kV (Peak) 125 kV 75 kV

Power

frequency

withstandvoltage

75 kV (r.m.s) 50 kV 28 kV

System

Earthing

Solidly earth

system

Solidly earth

system

Solidly earth

system


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General Consideration for 33/11 kV, 33/22 kVand 22/11 kV Sub-stations and SwitchingStations

The sub-station shall be designed and constructed complyingwith the requirements mentioned in these standards,applicable Indian Standards (IS) as well as other rules andregulations as per latest amendments. The design andconstruction of the sub-stations shall be such that they

perform their intended functions. In case of conflict the morestringent provisions shall prevail.

The sub-station shall be indoor/ outdoor or underground typedepending upon the site requirement. The sub-station shall beeither air insulated (AIS) or gas insulated (GIS), as the casemay be.

The sub-stations in urban areas shall be provided withSupervisory Control and Data Acquisition (SCADA) System formonitoring and control.

General Consideration for 33/11 kV


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General Consideration for 33/11 kV,33/22 kV and 22/11 kV Sub-stationsand Switching Stations

The sub-station shall be designed and constructed complyingwith the requirements mentioned in these standardsapplicable Indian Standards (IS) as well as other rules andregulations as per latest amendments. The design andconstruction of the sub-stations shall be such that they

perform their intended functions. In case of conflict the morestringent provisions shall prevail.

The sub-station shall be indoor/ outdoor or underground typedepending upon the site requirement. The sub-station shall beeither air insulated (AIS) or gas insulated (GIS), as the casemay be.

The sub-stations in urban areas shall be provided withSupervisory Control and Data Acquisition (SCADA) System formonitoring and control.


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Sub-station Layout

The layout of the Sub-station shall be such that:

The incoming and outgoing feeders are easilytaken to and from the sub-station structures.

Equipment maintenance shall be possible without

interrupting the entire supply.

The layout shall be economical and shall nothinder future expans ion.


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Switching Arrangements

Switching arrangements shall ensure operational flexibility,system safety and reliability.

Single bus, single bus with bus sectionalizer, main andtransfer bus, double bus or mesh arrangement shall beadopted as per requirement.


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System Configuration

The system configuration shall be radial, ring orcombination of both as per requirements. Theradial configuration s hall be minimized toimprove reliability. In densely loaded city centers,

and for essential services and installations, thesystem shall be of ring configuration.


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Sub-Station Construction andMain Equipment Selection

The control room building can be single storey or doublestorey or underground depending upon availability of space.

Concrete padding of appropriate thickness depending uponthe weight of the structures shall be provided in theswitchyard.

While selecting equipment for the sub-station, de-rating dueto increase in altitude and for cables due to depth of burial inthe ground shall be given due consideration as per thealtitude/depth of burial at the site.


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Power Transformers

The transformers and fittings and accessories shall complywith the relevant IS.

The 33/11 kV or 33/22 kV or 22/11 kV transformers shallhave delta star or delta-zigzag winding connection. At existingsub-stations, the percentage impedance, vector groups, on

load tap changer connection and range etc. of the newtransformer shall match with that of the existing transformer.

The preferred ratings for 33/11 kV or 33/22 kV or 22/11 kVtransformers shall be 6.3, 8, 10, 16 and 20 MVA for urbanareas and 1, 1.6, 3.15, 5 and 6.3 MVA for rural areas.

The transformers shall be three-phase type.


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The transformer can be oil filled, gas filled epoxy cast dry typeor ventilated dry type depending on whether it is installedindoor or outdoor. Outdoor dry-type transformer may be non-ventilated type.

Transformers shall withstand, without injurious heating,combined voltage and frequency fluctuations which produce

the over fluxing conditions as : 125% for 1 minute and 140% for 5 seconds.

The maximum temperature rise of oil and winding shall be 35

C and 40C respectively over an ambient temperature of 50C

Each transformer shall be provided with gas and oil actuated

Bucholtz relay fitted with alarm (local and remote) and tripcontacts, if applicable.


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A transformer with off-circuit tap changer shall have tapsranging from (+) 2.5% to (-) 10% in steps of 2.5% each onthe higher voltage winding for variation in the voltage. Thetap changing switch shall be located in a convenient positionso that it can be operated from ground level. The switch

handle will be provided with a locking arrangement along-with tap position indication, for locking the switch.

On load tap changing device shall be provided withtransformers of 3.15

MVA and higher rating for better voltage control by manualand automatic means.

A transformer with on-load tap changer shall have tapsranging from (+) 5% to (-) 15% in steps of 2.5% each on 33kV or 22 kV winding for voltage variation.


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Assembly of fittings and accessories shall be carried out asper the manufacturers instructions.

Adequate electrical clearances shall be provided from variouslive points on the transformer to earthed parts.

Transformers shall be separated from one another and from

all walls and partitions to permit free circulation of aircomplying with requirements of relevant IS.

33 kV voltage rating transformers shall be separated from oneanother by a fire wall.

Space shall be provided in front and rear sides of the

transformer conforming to Central Electricity Authority(Measures relating to Safety and Electricity Supply)Regulations as and when these are notified by the Authority.

(17)


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For indoor installation, the room shall be well ventilated forescape of heated air. Air inlets shall be provided near the floorand outlets near the ceiling.

A transformer shall be physically checked and tested for itselectrical and mechanical performance characteristics before

commissioning. A transformer shall be provided with two separate body

earthing terminals which in turn shall be connected to twoseparate earth points, besides neutral earthing terminal.


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Circuit Breakers

Circuit Breakers (CBs) shall comply with the provisions ofrelevant IS. The circuit breakers shall be SF or vacuum type.Normally vacuum type circuit breakers shall be used forvoltage levels of 33 kV and below. The rated voltage for thecircuit breakers shall be 36 kV, 24kV and 12 kV for 33 kV

22kV and 11 kV systems respectively.Rated short time current rating of 33 kV CBs shall not be lessthan 25 kA for 1 second and for 22 kV or 11 kV CBs shall notbe less than 16 kA for 1 second. In case of rural areas for 11kV CBs, this shall not be less than 12.5 kA for 1 second.

The operating mechanism shall be motor operated spring

charged type, anti pumping and trip free.


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The 33 kV, 22kV and 11 kV switchgears can be locatedoutdoor or indoor.

The indoor switchgears shall be metal clad, either fixed typeor draw out type.

A circuit breaker shall be mounted on individual structure in a

fixed position in such a way that adequate sectionalclearances are always available from its live parts.

The rated rupturing capacity of the circuit breaker to beinstalled at any new sub-station shall be at least 25% higherthan the calculated maximum fault level at the bus to takecare of the increase in short circuit levels as the systemgrows.

33 kV and 11 kV Isolators and


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33 kV and 11 kV Isolators andEarthing Switches

The isolators shall comply with relevant IS. The rated currentshall be at least 630 A at 36 kV and 24 kV. For 11 kV system,isolating switches of 400 Amps at 12 kV shall be used. Theisolators shall be gang operated type.

The frame of each isolator switch shall be provided with a

separate earthing terminal for each phase for connection toan earthing conductor.

The operating mechanism for the isolators and the controllingcircuit breaker shall be interlocked so that the isolators cannotbe opened unless the corresponding breakers are in openposition.

Earthing switches shall be provided at various locations tofacilitate maintenance. Main blades and earth blades shall beinterlocked, both electrically and mechanically.


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Insulators

Adequate insulation is of prime importance for ensuringreliability of supply, safety of personnel and equipment, etc.The station design shall be such that number of insulators isminimum but at the same time reliability of supply is ensured.

The insulators shall be porcelain or polymer type.

Suitable means shall be provided to accommodate conductorexpansion and contraction and there shall not be any unduestress on any part or equipment due to temperature change.

The minimum creepage distances for different pollution levelsshall be as per


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Post Insulators

The post insulators shall be of pedestal type and shall conformto relevant IS.

In the areas where problem of insulator pollution is expected(such as near sea or thermal power station, railway station,industrial area, etc.) special insulators viz. semi conducting

glazed porcelain or polymer insulators with higher leakageresistance and creepage distance shall be used.

Control and Relay


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Control and RelayPanels

The control and relay panels shall contain control andmetering equipment, relays and annunciation systems forincoming feeders, outgoing feeders, bus bars, switch-gearswherever indoors, instrument transformers and capacitors.

The control and relay panel shall consist of separate cubicle

with side covers made of sheet steel and shall be completewith internal wiring, terminals, ferrules and illuminationoperated with door off and on switch.

The panel shall be suitable for floor mounting and shall becompletely dust and vermin proof.


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The panel shall be provided with:

Suitable over current and earth fault relays to protect theequipment and system against short circuit current and earthfault current. The relays shall conform to relevant IS. Allrelays used shall be suitable for operation with CTs of

secondary rated for 1 Amp or 5 Amps.Measuring instruments such as ammeter, voltmeter andenergy meter for 33 kV, 22 kV and 11 kV systems.

Mimic diagrams.

Annunciation, alarms and trip facilities.

Panels shall have degree of protection conforming to relevantIS

33 kV and 11 kV Lightning


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33 kV and 11 kV LightningProtection

The surge arrester (SA) which responds to over-voltageswithout any time delay shall be installed for protection of 33kV switchgear, transformers, associated equipment and 33 kVlines.

Station class, heavy duty, gapless metal oxide (ZnO) type

surge arresters in general shall be provided on the buses,high voltage and low voltage sides of


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The rated voltage, continuous operating voltage, energyhandling capability, nominal discharge current and othercharacteristics of surge arresters shall be chosen inaccordance with system requirements.

Surge arresters shall be single-phase units suitable for

outdoor duty. These arresters shall draw negligible current atoperating voltage and at the same time offer least resistanceduring the flow of surge current.

The rated voltage of surge arresters shall be 30 kV for use on33 kV systems and with nominal discharge current rating of10 kA. For system voltage of 22kV, the rated voltage shall be

20 kV with nominal discharge current rating of 7.5 kA.


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The rated voltage of surge arresters shall be 9 kV (rms) forsolidly earthed 11 kV system (co-efficient of earth notexceeding 80 per cent as per relevant IS) with all thetransformer neutrals directly earthed. The nominal discharge

current rating shall be 5 kA.

Surge arresters for transformers shall be mounted as near thetransformers as possible and the star point shall be connectedto the independent earthing point.

Surge arresters shall be connected to two independentearthing connections.

The earthing lead for surge arrester shall not pass throughany iron or steel pipe, and shall be taken as directly aspossible from the surge arrester to a separate earth electrodeor junction of the earth mat already provided for the sub-station. Bends shall be avoided

I t t T f (C t d


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Instrument Transformers (Current andVoltage Transformers)

Current transformers (CTs) Current transformers shall comply with relevant IS.

The rated currents and ratio, the number of secondary cores(protection/metering), accuracy class, burden, secondarywinding resistance, knee point voltage, instrument security

factor and excitation current shall be as per the requirementsof the protection and metering system.

The primary side rating shall depend on the rating of thepower transformer of the sub-station. Current transformerswith secondary side rating of 1 Amps or 5 Amps shall beprovided. Where the distance between the primary equipmentand relay panel is large, CT of 1 Amp secondary current maybe used to avoid large VA burden on the CT.


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The CT may be oil filled or resin type for outdoor use and shallnormally be cast resin type for indoor use.

The accuracy class for metering core shall be equal to orbetter than the accuracy class of the meter specified in theCentral Electricity Authority (Installation and Operation of

Meters) Regulations, 2006.

Voltage transformers (VTs)


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Voltage transformers (VTs)

Voltage transformers shall conform to relevant IS. The number of secondary cores (protection/metering),

accuracy class and burden shall be as per the requirements ofthe protection system.

Voltage transformers shall be of electromagnetic type.

The voltage transformers shall be oil filled or cast resin typefor outdoor use. The indoor voltage transformers shallnormally be cast resin type.

The neutral point of star connected secondary windings ofvoltage transformers shall be earthed. Multiple earthing ofvoltage transformers shall be avoided under anycircumstances.

The accuracy class for metering core shall be equal to orbetter than the accuracy class of the meter specified in theCentral Electricity Authority

Earthing


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EarthingArrangement

Earthing shall be provided for: (a) Safety of personnel.

(b) Preventing and minimizing damage to the equipment as aresult of flow of heavy fault currents.

(c) Improving reliability of power supply.

Earthing shall be carried out in accordance with relevant ISand Central Electricity Authority (Measures relating to Safetyand Electricity Supply)Regulations as and when these arenotified by the Authority.

The step and touch potentials shall be within safe limits.

Control


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ControlRoom

Control room shall be provided to house the control and relaypanels and all other indoor equipment, and measuring andrecording instruments required for control and operation ofthe sub-station.

Adequate space shall be provided for the operation and

maintenance staff. Provision of space for future expansion shall also be kept


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Reactive Power Compensation

Shunt capacitors shall be connected on secondary side of33/11 kV, 33/22 kV or 22/11kV transformers.

Capacitors and the residual voltage transformer shall be asper relevant IS.

The capacitors shall be of automatic switched type for sub-

stations of 5 MVA and higher capacity. Where un-switched (fixed) capacitors are provided, the rating

shall be chosen so as to prevent over compensation during offpeak periods.

Each capacitor unit shall be provided with a built-in dischargeresistor of adequate rating to discharge the residual voltageas per relevant IS.

The capacitors shall be fixed firmly to the supporting structureto make them immovable.


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The capacitors shall be earthed appropriately to avoidaccidental leakage of charge.

Where the sub-station is feeding loads which have highharmonic levels ,suitable harmonic filters shall be installed.

In cases of sub-stations loaded with highly fluctuating loads

like arc furnaces etc., flickers and voltage regulation problemsshall be overcome by installation of static var compensators(SVC).


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Cables

Power and control cables of adequate current carryingcapacity and voltage rating shall be provided.

Power cables shall be XLPE insulated, PVC sheathed typeconforming to relevant IS. Cables shall be flame retardant lowsmoke (FRLS) type. Cables shall be de-rated for the sites

ambient and ground temperature, grouping and soil resistivityas per IS. Proper attention shall be given to ventilation/heatdissipation aspects particularly in case of HV cables.

The control cables shall be of copper and conform to relevantIS.

Cables shall not be laid directly on the trench floor.


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The cables shall be segregated by running in separatetrenches or on separate racks, with the highest voltage classcables laid at the highest racks/tiers.

The cable trenches shall be properly sloped so as to drainfreely any water which may enter.

Care shall be taken in sub-station design to permit easy entryof cables into switchgear and convenience of handlingafterwards.

Segregation of AC and DC control cables and power cablesshall be done.

Separate control cables shall be used for each CT and VT.

Sufficient extra length of cable shall be provided for repair offaults in terminations inside the switch gear.


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Cable laying shall be done as per manufacturersrecommendation. The relevant drawings of cable sizes,routes and the termination details of control cables in thepanels shall be available at work site and shall be preservedfor future use and reference in the sub-station.

All cable ends shall be suitably labeled to facilitate easyidentification.

Ferrules used on ends of control cables shall match with thedetails shown in the relevant termination drawings.

Adequate number of spare cores shall be included in allcontrol cables.

Telecommunication


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System

The telecommunication system shall be reliable. A dedicated telecommunication system i.e. radio, mobile

telephone, satellite or a combination of these shall beprovided, besides usual public communication and local PublicAddress (PA) system.

The radio communication network shall be in the VHF/UHFfrequencies.


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Automation System

State-of-art systems such as supervisory control and dataacquisition system (SCADA) and data acquisition system(DAS) shall preferably be provided in the 33 kV or 22 kV sub-stations, associated feeders and distribution transformers forimproving the operational flexibility, minimizing restoration

time of power supply and preventing overloading of lines andtransformers in real time mode.


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Sub-station Support Facilities

DC supply arrangement The battery charger, battery and load shall be connected in

parallel and work as a system.Battery

(a) The 24V/ 30V/ 48V DC batteries shall be stationary leadacid or nickel cadmium type. The capacity and discharge rateshall be as per the load requirement.

(b) The batteries shall conform to relevant IS


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Battery charger The battery chargers shall be of static type. The battery

charger shall be capable of continuous operation at the ratedload in float charging mode. The charger in boost chargingmode shall be capable of boost charging the associated DCbattery at the desired rate.

Auxiliary power supply transformer

An auxiliary power supply transformer of adequate capacityconnected to the 33 kV or 22 kV or 11 kV bus shall beprovided to meet the auxiliary and lighting loads of the sub-station.


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Oil and SF6 evacuating, filtering, testing and fillingapparatus

Oil and SF6 filling, evacuation, filtering and testing plants withadequate storage facilities shall be provided for a cluster ofsub- stations as per requirement.


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Lighting System

Energy efficient lighting system shall be provided at the sub-station. The lighting system shall comprise of the following:

AC normal lighting

AC lights shall be connected to AC lighting panels. All thelights connected to the AC lighting system in different areas

shall be connected to the main lighting distributionboard(LDBs).

DC emergency lighting

Emergency lighting operated on the DC system shall beprovided in strategic locations viz. control room, batteryroom, passages etc


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Fire Fighting System

Proper attention shall be given to isolation, limiting andextinguishing of fire so as to prevent damage to costlyequipments, reduce chances of serious interruption of powersupply and ensure safety of personnel. The layout of the sub-station itself shall be such that the fire shall not spread fromone to other equipment and areas as far as possible.

Fire hydrant, carbon dioxide (CO2) type fire extinguisher ordry chemical powder type fire extinguisher conforming torelevant IS shall be provided as per site requirement.

presentation slide on the requirement of kt or ks as in-house workshop

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