check list for protection audit (1)

7/29/2019 Check List for Protection Audit (1)

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Check List for Transmission Line

Name/Details:

Sl. No Protection Scheme Status ** Remarks

1. Main I-Distance Protection Yes/No

2. Main II-Distance Protection of directionalcomparison protection or phase segregated

line differential protection

Yes/No

3. Directional instantaneous definite

minimum time (IDMT) type earth fault

relay

Yes/No

4. Directional IDMT over current and earth

fault back up protection

Yes/No

5. Two stage over voltage protection Yes/No

6. Auto Reclosing Yes/No

7. Carrier aided inter-tripping/blocking

feature

Yes/No

8. Are Power Line Carrier Communication

(PLCC) equipment with Protection

Coupler complete for speech transmission,

line protection and data channels

provided?

Yes/No

Yes/No

Yes/No

9. Are 100% back up Communication

Channels provided for transmission line &

line compensating equipment?

Yes/No

10. Disturbance Recorder Yes/No

11. Distance to Fault Locator Yes/No

12. Event Logger:i) Stand Alone

ii) Part of S/S or switchyard

automation system

13. Are Time Synchronizing Equipment (TSE)

complete with antenna, all cables,

processing equipments etc. provided to

receive synchronizing pulse through Global

Yes/No


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Positioning System (GPS) compatible for

synchronization of event logger,

disturbance recorder and

SCADA/automation system ?

14. Are all protection employed Numerical

type?

Yes/No

15. Are two protection channels in addition to

one speech plus data channel provided for

each direction?

Yes/No

16. Local Breaker Backup Protection (LBB) Yes/No

17. Any other Protection

** Check the availability & functional healthiness.

Note:

a) Sl No.2 is optional at voltage level 220KV & not required at voltage level 132KV;

b) Sl No.3 is required at 220 KV if both Main-I & Main-II are distance protections,

otherwise not required. At 132 KV level it is not required;

c) Sl No.4 is required at 220 KV level if Main-II is not provided, otherwise not.

d) Sl No.14 is required at 220KV and above;


3/14

Check List for Transformer

Name/Details:


1. Differential Protection Yes/No

2. Over Fluxing Yes/No

3. Restricted Earth Fault Yes/No

4. Backup directional over current and earth

fault protection (HV & LV side) or

impedance protection

Yes/No

5. Buchholz Yes/No

6. Winding Temperature Indicator (WTI) Yes/No

7. Oil Temperature Indicator (OTI) Yes/No

8. Magnetic Oil Gauge (MOG) with low oil

level alarm

Yes/No

9. Oil Surge Relay (OSR) for On Load Tap

Changer (OLTC)

Yes/No

10. Pressure Relieve Device (PRD) Yes/No

11. Surge Arrester (SA) on both primary and

secondary sides of transformers located

outdoors and connected to over head lines

Yes/No

12. Tertiary winding protection Yes/No

13. Over load alarm Yes/No

14. Cooling

15. Any other protection


Note:

a) Sl No.6 is required at voltage level 220KV for 100MVA & above rating ;

b) OTI is required for 1 MVA and above;


4/14

Check List for Reactor

Name/Details:


1. Differential Yes/No

2. Restricted Earth Fault (REF) Yes/No

3. Reactor backup protection (impedance

type or definite time over current (O/C)

and earth fault (E/F) protection)

Yes/No

4. Buchholz Yes/No5. Winding Temperature Indicator (WTI) Yes/No

6. Magnetic Oil Gauge (MOG) Yes/No


8. Surge Arrestor (SA) Yes/No

9. Cooling




5/14

Check List for Sub-Station/Switchyard

Name/Details:


1. Local Breaker Backup (LBB) Yes/No

2. Event Logger (EL) Yes/No

3. Synchronizing Facility Yes/No

4. Are Synchro Check Relay provided with requisite

settings? Yes/No

5. DC supply:i) 48V

ii) 110V

iii) 220V

Yes/No

Yes/No

Yes/No

6. DG set Yes/No

7. Auxiliary Supply Yes/No

8. Special Protection Scheme (SPS) Yes/No

9. Under Frequency Relay(UFR):

i) Stage I

ii) Stage II

iii) Stage III

Yes/No

Yes/No

Yes/No

10. Has the Fault level Increased since connected togrid? Yes/No

11. If status at Sl.No 1 isYes, then whether

Sectionalisation of the bus/ Series Reactor on the

line or bus provided to limit the fault level? Yes/No

12. Has the size and number of ICT in the S/S been

planned in a way that the outage of any single unit

does not overload the remaining ICTs or the

underlying transmission system

Yes/No

13. SCADA:i) Voice

ii) Data

Yes/No

Yes/No

14. Switching Schemes Yes/No

15. Are Circuit Breakers suitable for single-phase and

three-phase auto reclosing? Yes/No


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16. Are Circuit Breakers provided with two trip coils? Yes/No

17. Are Circuit Breakers provided with Pre Insertion

Resistors?

Yes/No

18. Are Earthing Switches provided at appropriate

locations to facilitate earthing of outgoingtransmission lines to enable maintenance?

Yes/No

19. Are all main protection relays of numerical type? Yes/No

20. Are protection functions subdivided into two

independent groups & capable of providing

uninterrupted protection even in the event of one

protection groups failing?

Yes/No

21. Are two sets of DC sources available? Yes/No

22. If status to Sl.No 21 is Yes, then whether relays are

electrically and physically segregated into two

groups to obtain redundancy and to take

protection systems out for maintenance while theequipment remains in service?

Yes/No

23. If status to Sl.No 21 is No, then whether relays are

electrically and physically segregated into two

groups by giving DC supplies through separate

fuses?

Yes/No

24. Bus Bar Protection Yes/No

25. Bus Bar Protection scheme has provision for future

expansion Yes/No



Note:

a) Requirements for Sl No.14 are:

Switching Scheme Voltage level

Main & Transfer Bus or Double bus 66KV & 132 KV

Double Main & Transfer Bus or Double bus 220KV

Breaker & a half or Double Main and

Transfer bus

400KV


7/14

Check List for Generator

Name/Details:


1. Is Power System Stabiliser (PSS)

provided in AVR for the generator? Yes/No

2. Is it possible to use the Generator

Transformer to provide start up power

from the grid?

Yes/No

3. Cooling of GT , UAT & ST Yes/No

4. Neutral Earthing

5. Are protection systems for Generator,

Generator Transformers, Unit

Auxiliary Transformers connected to

two independent channels/groups?

Yes/No

6. Generator Differential Yes/No

7. 100% Stator Earth Fault Yes/No

8. 95% Stator Earth Fault Yes/No

9. Standby Stator Earth Fault Yes/No10. Interturn Fault Protection Yes/No

11. Loss of field Yes/No

12. Negative phase sequence Yes/No

13. Low Forward power & Reverse power

interlock for steam turbine generator

Yes/No

14. Rotor Earth Fault Yes/No

15. Definite Time overvoltage Yes/No

16. Generator Under Frequency Yes/No

17. Over Fluxing for generator Yes/No

18. Overload Yes/No

19. Back up Impedance Yes/No20. Overheating (winding and/or bearing) Yes/No


8/14


9/14

Check List for Generator Transformer

Name/Details:


1. Overall Differential Yes/No

2. Rstricted Earth Fault Yes/No3. Overhead line connection Differential Yes/No

4. Back up Earth Fault on GT HV Neutral Yes/No


6. Back up non directional over current in

all phases of on HV side of GT Yes/No

7. Oil Temperature Indicator (OTI) trip Yes/No

8. Winding Temperature Indicator (WTI)

trip

Yes/No

9. Buchholz Yes/No

10. Pressure Relief Valve Yes/No

11. Pole Discrepancy of GT breaker Yes/No12. Breaker failure of GT breaker Yes/No

13. Start-up Earth fault of LV and HV

winding of GT and UAT Yes/No




10/14

Check List for Unit Auxiliary Transformer

Name/Details:

Sl. No Protection Scheme Status ** Remarks1. Differential Yes/No

2. LV back up Earth Fault Yes/No

3. LV Restricted Earth Fault Yes/No

4. Back up Over current Yes/No

5. Oil Temperature Indicator (OTI) trip Yes/No

6. Winding Temperature Indicator (WTI)

trip

Yes/No

7. Buchholz Yes/No

8. Pressure Relief Valve Yes/No

9. Any other Protection Yes/No



11/14

Check List for Station Transformer

Name/Details:


1. Differential current Yes/No

2. Restricted Earth Fault for LV winding Yes/No3. Restricted Earth Fault for HV winding Yes/No

4. Back up over current on HV side Yes/No

5. Back up Earth Fault Yes/No



8. Winding Temperature Indicator (WTI) Yes/No

9. Buchholz Yes/No

10. Pressure Relief Valve trip Yes/No

11. Breaker failure of GT breaker Yes/No




12/14

Check List for HVDC

Name/Details:


1. Are DC Converter Terminals-

i) Manned by Operator

ii) Controlled by Remote Operation of

SCADA system

Yes/No

Yes/No

2. Is control system hierarchy followed? Yes/No

3. Has HVDC Bipole the needed control

features as given in note (b) Yes/No

4. Are modules for pole control, converter

control and valve control provided?

Yes/No

5. Does AC side protection function cover the

zone for converter transformer, AC filters,

shunt capacitors, shunt reactors and bus

bars?

Yes/No

6. Does AC protection follow the same

philosophy as in a typical substation i.e.

detection of fault by relay and tripping of

circuit breaker?

Yes/No

7. Does DC side protection function cover thezones consisting of valve hall, DC

switchyard including smoothing reactor &

DC filters, DC line, electrode line and

ground electrode?

Yes/No

8. Do AC & DC protection system each have

two identical independent electrical and

mechanical systems with following

protections----

i) Converter differential

ii) DC over current

iii) DC differentialiv) AC conductor ground fault

v) Commutation failure

vi) DC filter protection

vii)DC smoothing reactor

viii) DC line ground fault

ix) DC line differential

x) DC under voltage

Yes/No

Yes/No

Yes/NoYes/No

Yes/No

Yes/No

Yes/No

Yes/No

Yes/No

Yes/No


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xi) DC overvoltage

xii)Electrode line monitoring &

protection

Yes/No

Yes/No

9. For requirements of reliability and fast

controllability of the HVDC system isprotection provided by numerical relays?

Yes/No

10. Are HVDC terminals provided with

reliable communication system?

i) Through Optical fibers

ii) Through PLCC

iii) Through PLCC & Optical fiber

both

Yes/No

Yes/No

Yes/No


Note:

a) The control system hierarchy in Sl. No. 2 shall be as follows:

(A)Bipole Control;

(B) Pole Control;

(C)Converter Control;

(D)Valve Control;

(E) VDCOL;

b) The HVDC Bipole shall have control features including but not limited to the

following:

(A)Reactive Power Controller;


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(B) Current & Power Controller;

(C)Frequency Controller;

(D)Power Modulator, Pole Power Compensation;

(E) Sub-Synchronous Resonance Damping Controller;

(F) Load Frequency Controller;

(G)Current Margin Controller;

(H)Excessive reactive power consumption Controller;

(I) AC system stability function, such as power swing damping function;

(J) NGH damping;

c) Sl No.8(vi) not required for back to back schemes;

check list for protection audit (1)

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