central electricity authority piscama xao~iya ivavut ...wrpc.gov.in/pcm/106pcm_minute.pdf · please...

Baart sarkar Government of India kond`Iya ivaVut p`aiQakrNa

Central Electricity Authority piScama xao~Iya ivaVut saimait

Western Regional Power Committee ef -3, emaAayaDIsaI xao~, AMQaorI (pUva-), mauMba[- - 400 093

F-3, MIDC Area, Andheri (East), Mumbai - 400 093

Aa[- esa Aao : 9001-2000 ISO : 9001-2000

dUrBaaYa Phone: 022- 28221681; 28200194/195/196; fO@sa Fax : 022 – 28370193 Website : www.wrpc.nic.in E-mail : [email protected]

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Please find enclosed herewith the minutes of 106th Protection sub-Committee Meeting of Western Regional Power Committee Mumbai, held on 01st & 02nd September 2009 at WRPC Mumbai for your information and necessary action.

¤¸¾“ˆÅ ˆÅ¸ ˆÅ¸¡¸Ä¨¸¼î¸ œ¸® ½̧¢¨¸ ¬¸¢Ÿ¸¢÷¸ ˆÅú ¨¸½¤¸¬¸¸ƒ’ www.wrpc.nic.in œ¸£ ž¸ú „œ¸¥¸¤š¸ í¾ — Minutes are also available at WRP Committee website www.wrpc.nic.in

š¸›¡¸¨¸¸™ /Thanking you

ž¸¨¸™ú¡¸/Yours faithfully,

sd/ (‡ma.Aar.isMah /M.R. Singh)

‚š¸ú. ‚¹ž¸.(£.)/Suptdg. Engr.(P.) ¬¸¿¥¸Š›¸ /Encl. :- „œ¸£¸½Æ÷¸¸›¸º¬¸¸£ /As above

MINUTES OF THE 106th PROTECTION COMMITTEE MEETING

The 106th Protection Committee Meeting of WRPC was held on 1st and 2nd September

2009 at WRPC Mumbai. The list of participants is placed at Annex -I.

Shri Manjit Singh, Member Secretary, WRPC, welcomed all the members and

invitees to the 106th Protection Committee Meeting. He stated that the protection related

matters are discussed in a very good technical spirit and since this forum is an open group

forum all suggestions and good inputs finally result in secure operation of the WR grid. The

members of this forum may always make continuous effort to arrive at improvement in the

protection system. Briefing the members on the issue he stated that, a follow up discussion

on the pilot project proposed by PGCIL would be taken up and the PCM forum may

deliberate on the feasibility of technical aspects of the project. He hoped that various

protections related issues would be resolved during this two day meet at WRPC Mumbai.

He then requested Shri S. Satyanarayan, Executive Engineer (Protection), WRPC to

take up Agenda items for discussion.

Item No.1: Confirmation of Minutes of 105th Protection Committee Meeting.

Executive Engineer (Protection), WRPC, stated that the Minutes of 105th PCM, held on

18th June 2009 at WRPC Mumbai, were circulated vide WRPC letter no. Prot./105

PCM/2009/WRPC-6994 dated 06th July 2009. Comments received from WRTS-II, PGCIL

regarding compliance of Annex.-4, were discussed. The Column III, Row iii (D) of Annex.-4

was modified as under,

“POWERGRID informed that they have implemented Analogue Triggering of DR

in all the Substations (O/C and O/V)”

With these modifications the Minutes of 105th PCM circulated vide above referred letter, were

confirmed.

Item No.2: System disturbances

2.01: System disturbances in GETCO/GSECL system

(i) System disturbance at 220 kV Tapper S/S in GETCO system on 02-05-2009.

GETCO representative informed that, on 02-05-2009 at 10:05 hrs., the 220

KV Tappar- Nanikhakhar-1, 220 KV Tappar- Sivlakha- 1, 200 KV Tappar- Sivlakha-

2 feeders tripped on Zone 2, B phase to earth from remote ends.

The 220 KV Tapper- Nanikhakhar-2 was under planned shut down for

maintenance work. During measurements of the breaker timings through the breaker

timing kit, the isolator was made ON to defeat the interlock by ignorance/human error

of the working Engineers/ staff. The bus isolator was not fully closed. The kit got

charged through breaker timing kit wires. It created fault of high resistive nature

burning the kit & wires. The ABB make RADSS Bus Bar protection scheme did not

operate. All the lines connected to Tappar S/S tripped from remote ends in zone-2,

resulting in no power at 220 KV Tapper S/S from 10.05 to10.20 hrs.

GETCO representative further told that the Bus Bar protection was tested and

the results were in order.

All the tripped lines were restored by 10:20hrs of 02.05.2009.

Committee observed that the fault was sensed and cleared by the remote

end relays of the lines connected to the Bus in zone-2, suggesting that the fault was

fed for the zone 2 timings. Further though the fault was of highly resistive in

nature (which would have been confirmed if the fault currents recorded by the

DRs of the remote relays would have been made available), the insensitivity of the

ABB make RADSS Bus Bar Protection scheme to such type of faults needs to be

taken up with the manufacturer.

The Committee further observed that while documenting standard

operating procedures, which are in process, the education of operating staff

should be included so as to avoid such man made mistakes.

(ii) System disturbance at 220 kV Wagra S/S in GETCO system on 31-05-2009.

GETCO representative informed that, on 31.05.2009 at 06:35hrs., 220 KV

Wagra-Haldarwa line tripped along with 220 KV Dahej, 220/66 KV 50 MVA T/F and

220 KV Bus Coupler on operation of the Areva make numerical Bus Bar protection

scheme at 220kV Wagra S/S.

There was a transient fault on the 220kV Wagra-Haldarwa line and the same

was sensed by the DPS in Z-1 at 220kV Wagra S/S. The fault was 1.73km away from

Wagra end. The Bus Bar Protection scheme at this newly commissioned Wagra S/S

operated simultaneously for this through fault. All the feeders were connected to Bus

A and Bus B was charged through Bus Coupler with out any feeder connected to it.

He further told that the CT connected to the Bus Bar scheme were wired with

wrong polarity resulting in operation of the Bus bar protection scheme for a through

fault of transient nature.

All the feeders were restored by 07:20hrs, except 220 kV Wagra-Haldarwa

feeder which was restored by 11:10hrs.

Committee felt that wirings should be checked at the time of initial

commissioning/testing of the Bus Bar protection scheme to avoid such avoidable

failures.

(iii) System disturbance at 220kV Vav S/S in GETCO system on 23-06-2009.

GETCO representative informed that, on 23.06.09 at 09:40hrs, all the feeders

connected to 220 KV Bus A and B/C breaker tripped while charging the 220/66 KV

100 MVA T/F -1 on 96 relay due to operation of LBB of the T/F-1 at 220kV Vav S/S.

The 100 MVA 220/66 KV transformer was under planned shut down. The

transformer tripped on Earth Fault due to high inrush current, during charging. The

LBB of this feeder operated due to delayed tripping of R phase pole of the

transformer breaker. The PDR also operated. After detailed investigation of breaker, it

was found that the delayed tripping of R-Ph pole of transformer was due to

weak/faulty Trip Coil-1.

He further told that the E/F relay provided for the transformer backup

protection is of ER make Argus-2 numerical relay having IDMT characteristics. The

LBB settings were 0.2Amps with a time delay of 200msec and the pole Discrepancy

relay timer settings were 500msec. The transformer was tested and the results were

found in order.

All the tripped feeders were restored by 10:48 hrs, except T/F-1 which was

restored at 19:50hrs after replacing the R Phase TC-1 of 100 MVA T/F No-1 breaker.

Committee felt that the inrush current sustaining for 10cycles is not a good

sign from the point of view of healthiness of the transformer as per the records of

the DR recorded by the relay. Further it was also felt that the transformer

Breaker should have tripped through the TC-2, in the event of failure of the TC-1.

(iv) System disturbance at Gandhinagar TPS in GSECL system on 07-05-2009.

GSECL representative informed that, on 07.05.2009 at 03:50hrs, B-phase PT of

220kV Bus-II stage-I got burst and fire broke out at Gandhinagar TPS. The Bus Bar

protection of Bus-II operated, due to which all the lines, T/F’s and Generators

connected to Bus-II tripped.

During yard inspection the post insulator (PT side) of B phase isolator was

found damaged and fell down along with the isolator contact arm.

He further told that the failed PT was of Hivoltrans Electrical Pvt. Ltd. make

and was commissioned on 09/01/2008. The failure of PT just after around 16 months of

commissioning was referred to the OEM of the PT. However no specific reason for

failure of the PT was given by the OEM.

All the tripped elements were restored by 09:50hrs of 07.05.2009.

Committee observed that the above tripping was in order. However the PT

should not have failed within 16 months of commissioning. The matter may be

taken up with the manufacturer.

(v) System disturbance at Sikka TPS in GSECL system on 04-06-2009.

GSECL representative informed that, on 04.06.2009 at 15:00hrs, a sound of

flashover was heard and simultaneously Bus Bar differential protection of 132 kV Bus

A operated, thereby tripping all the lines, T/F’s and generators connected to Bus A at

Sikka TPS.

132kV Dhrol and 132kV Naghedi lines connected to Bus-B, tripped from

remote ends on distance protection. Inspection of 132kV switch yard was done and also

PID of 132kV Bus and Bus Coupler tension string was carried out. However no

abnormality was observed.

He further told that a piece of armour wire or conductor might have fallen on

the Bus resulting in a transient Bus fault. The Bus Bar protection scheme is of high

impedance, UV make scheme. As regard to trippings 132kV Dhrol and 132kV Naghedi

lines connected to Bus-B, the Bus Coupler timings were checked and were found in

order.

Normalcy was restored by 17:05hrs..

Committee observed that the tripping of feeders connected to Bus-A on

operation of the Bus Bar protection is in order. However tripping of 132kV Dhrol

and 132kV Naghedi lines connected to Bus-B from remote ends in Zone 3 timing is

highly undesirable for a Bus fault of transient nature and in view of the normal

test results of the Bus Coupler breaker timings. It was also pointed out that if

PMU data comes into the system such failures could be precisely detected and

rectified.

2.02: System disturbance in MPPTCL/MPPGCL system

(i) System disturbance at 400 KV S/S Nagda in MPPTCL system on 23-05-2009.

MPPTCL representative informed that, on 13.05.2009 at 22:45hrs, B phase CT of

SCT make bearing Sr.No.2005/376 of 220kV Nagda-Ratlam-I feeder failed at 400kV

Nagda S/S. 220 KV Ratlam-I feeder was connected on Bus-I. Due to failure of this CT the

ER make 220 KV Main-I Bus-bar protection scheme CSC-150 operated thereby tripping all

the feeders connected to Main-bus-I and isolated the fault in 52msecs.

He further told that the CT was commissioned in October 2007 and the test results

of the CT at the time of commissioning were in order.

Normalcy was restored by 07:55hrs.

Committee observed that the operation of the Bus Bar protection is in

order. However the non-tripping of 220kV Nagda-Ratlam-I feeder at local end

and tripping of this feeder from remote end in Zone 2 is incorrect. The Circuit

Breaker control circuit of this feeder at Nagda end needs to be thoroughly

checked.

2.03: System disturbance in MSETCL/MSEGCL system

(i) System disturbance at 220kV GTPS Uran S/S in MSETCL system on 19-04-

2009.

MSETCL representative informed that, on 19.04.2009 at 22:45hrs, the B-ph

line PT of 220kV Uran-Apta feeder got busted at 220kV Uran S/S. The 220kV Bus

bar Zone-2 operated and tripped all the connected feeders to Bus-II except 220kV Bus

Coupler.

The line PT & CTs are installed very near in line bay between line & transfer

bus isolator. The bursting of the PT created a bus fault. However the Bus Coupler did

not trip, since at same time the bus interconnection operated, due to tripping of DC

supply MCB of GT units 5, 6, 7, and 8, isolator contact logic thereby clubbing the

Zone-1 and Zone-2 and disabling the Bus Coupler trip. The LBB protection of the

Bus Coupler operated resulting in tripping of all the feeders connected to 220kV Main

Bus-I. 220kV Uran-Apta-II tripped from remote end in Zone 2. There was a loss of

generation of around 360MW at GTPS Uran.

He further informed that the PT was commissioned on 18.04.2009. The Bus

Bar Protection is of Siemens make static Bus Bar scheme. The 220kV Uran- Apta-II

line CB was tested for breaker timings and the results were in order.

Normalcy was restored by 09:06hrs of 20.04.09, except Unit#7, which was

restored at 01:17hrs of 21.04.09.

Committee observed that with the operation of the Bus Inter-connector and

Bus Zone-2 protection, all the 220kV feeders connected to the Bus –I should have

also tripped (due to clubbing of Bus Zone-I & II), thereby isolating the fault being

fed from remote end sources and local sources connected to Bus-I. Due to failure

of DC supply meant for isolator logic of GT unit 5,6,7 & 8 and in view of the Bus

Inter-connecter operated (thereby blocking the Bus Coupler trip), the fault was

being fed by these generators from Bus-I and from Bus-II through the Bus

Coupler till the backup protection of the GTs cleared the fault. However the

tripping of 220kV Uran-Apta-II in Zone 2 at Apta end is undesirable. The trip

control circuit of this feeder at Uran end should be checked thoroughly in view of

the CB timing test results of the CB were in order. Also the control circuit of

extension of Bus Bar trip command to all the feeders needs to be checked.

(ii) System disturbance at 400kV Karad S/S in MSETCL system on 19-05-

2009.

MSETCL representative informed that, on 19.05.2009 at 12:03hrs, the B phase

jumper of 220kV Bus Coupler bay snapped from isolator end (Bus-II isolator) and fell

on ground creating a Bus fault. The fault was fed by Bus-1, but it was out of Bus-1

Zone fault. The fault was not fed by Bus-2 since the jumper got opened from Bus-2

isolator end. The ABB make RADSS Bus Bar protection scheme did not operate for

this fault and the fault was cleared by tripping of 400 kV New Koyna Ckt. II (Zone

3), 400 kV Lamboti (Zone 2), 400 kV Lonikand (Zone 2), 220 kV Pophali (Zone 3),

220 kV Pedambe, 220 kV Malharpeth (Zone 2), 220 KV Kolhapur ckt. IV (Zone 2)

lines from remote end and 400/220 kV ICT III. The ICT-I and ICT-II did not trip

during the occurrence. There was a loss of load of the order of 825MW in the

Kolhapur region of Maharashtra and Goa states.

He further informed that the Bus Coupler is not provided with any protection

also directional Back up protection is not provided for ICT-I. The Bus Bar Protection

scheme was tested on 29th & 30th May 2009 and the scheme was found working

correctly. ABB will carry out detailed investigation in Sept 09 and submit its report.

Thermo vision scanning of the S/S was carried out after the incidence. It has also

been decided that the 220kV Bus Coupler will be provided with IDMT over current

and earth fault protection relays with high set feature.

All the 400kV lines and ICT’s were restored by 13:30hrs.

The presentation given by MSETCL is enclosed at Annex- 2.03 (ii).

Committee observed that though the fault was out of zone fault for Bus

Zone-1, the fault would have been sensed in the Bus zone-II by the Bus Bar

protection scheme. The matter may be taken up with M/s ABB for not sensing the

fault, in view of the fault contribution recorded by the remote end DRs. Also had

the earth fault protection been provided to the Bus Coupler, the fault would have

got isolated. Committee also felt that tripping of 400kV lines and 220kV lines from

remote ends in Zone 2 is undesirable and ICTs should be provided with

directional back up protection on HV and LV sides.

2.04: System disturbance in NPCIL system

(i) System disturbance at 2x220MW KAPS ATPS in NPCIL system on 02-04-

2009.

NPCIL representative informed that, on 02.04.2009 at 13:26hrs, all the 220kV

feeders connected to Bus Bar-1 tripped, on Bus Bar differential protection at KAPS

ATPS.

During yard inspection a section of Y-phase Bus bar was found bent at the

extreme end of the 220kV Main Bus-I. A section of the Y-phase Bus Bar was found

bent. Lower stack of extreme end Bus post insulator was found in snapped condition

near its third skirt from to whereas its remaining part was still intact on structure. Upper

stack of this extreme end Bus post insulator remained connected. Bus support clamp of

third last Bus post insulator consisting of Bus joint also found cracked from its base.

Some of the post insulators were found broken with slight soot on the surface of Main

Bus Bar tube and Bus support clamps. The R-phase Bay Bus of Bay No.13 (Haldarwa

No.1 feeder) was also found bent with Bus support insulator clamp broken and Circuit

Breaker end support clamp deformed.

He further informed that two sets of 220kV Y phase Bus-1, Bus post insulators

replaced and R phase Bus support clamps and CB connection clamps of 220kV

Haldarwa -1 were replaced. All other Bus post insulators of Bus-1 were thoroughly

inspected for damage/crack.

The 220kV KAPS-Vapi#1 and KAPS-Vav#1 charged on 02.04.09, 220kV

KAPS-Haldarwa#1 & 2 charged on 04.04.09 and 220kV Bus Bar#1 normalized on

06.04.09.

Committee felt that the clamping arrangement of Bus post insulator as

described by NPCIL representative is as per the standard practice. The Bus post

insulators might have failed due to mechanical stress and aging of the insulators

hence special attention to condition monitoring of the older equipment needs to be

done. Also, NPCIL may examine the need of increase in number of supports.

2.05: System disturbance in PGCIL system

(i) System disturbance at 400kV Jabalpur S/S in PGCIL system on 12-05-

2009.

PGCIL representative informed that, on 12.05.09 at 14:06hrs, the B phase to

Earth fault appeared on 400kV Vindhyachal-Jabalpur#1 line, but due to persisting fault,

it led to 3-ph tripping of the line. Simultaneously the Y-ph grading capacitor (line side)

of the Tie bay breaker of the 400kV Vindhyachal Jabalpur #1 line failed at Jabalpur

S/S.

During tripping of 400kV Vindhyachal-Jabalpur#1 line, the Y-ph grading

capacitor of the tie bay of 400kV Vindhyachal-Jabalpur#1 line (line side) got blasted.

Initially, this fault was outside the zone of Busbar protection, but the arcing spread to

Tie CT included in Busbar zone (in around 300ms) resulting in operation of Bus-bar

protection of Bus-2. This led to tripping of all the breakers connected to bus-2, which

would have cleared the fault. However, till that time the fault was sensed by other

feeders also, namely 400kV Vindhyachal-Jabalpur#2, 400kV Jabalpur-Itarsi#1&2 and

tripped on operation of Main-I/Main-II protection. The 400kV Vindhyachal-Jabalpur #

3 & 4 and Jabalpur-Itarsi #3 & 4 tripped on operation of over voltage stage-I protection.

He further told that the BHEL make Grading Capacitor was more than 20yrs old

and was last tested in 2007 and its tan delta value was within limits (0.0039). As a

preventive measure, all the non numerical static type of relays are being replaced with

latest numerical relays.

All the lines were restored by 17:55hrs of 12.05.09.

Committee observed that the operation of Bus Bar protection scheme is in

order. However the trippings of 400kV Vindhyachal-Jabalpur#2, 400kV

Jabalpur-Itarsi#1&2 on operation of Main-I/Main-II protection and sensing the

fault in reverse direction is incorrect. Also operation of over voltage stage –I

protection of 400kV Vindhyachal-Jabalpur # 3 & 4 and Jabalpur-Itarsi #3 & 4

lines is undesirable in view of increase in loading on these feeders due to tripping

of other evacuating circuits.

(ii) System disturbance at 400kV Rajgarh S/S in PGCIL system on 17-06-2009.

PGCIL representative informed that, on 17.06.09 at 07:14hrs, 400kV Rajgarh-

SSP # 1 tripped on R ph to Earth fault due to snapping of R-phase conductor. After

approximately 1 sec., Auto Reclosure attempt took place, but the fault was persisting

since the snapped R Phase conductor fell down on B –phase creating phase to phase

fault, resulting in 3-phase tripping of the line. The Bus Bar protection of Bus-I also

operated at the same time, leading to tripping of 400kV Rajgarh-Nagda # 2 line on D/T.

Other lines connected on this Bus were already out of service due to system constraints.

He further told that, due to scheme problems, three phase tripping of Rajgarh-

SSP-1 feeder took place and it Auto-reclosed. The scheme wiring problem was

attended. The Bus-bar protection mal-operated for through fault and also DT was also

sent to other end for Rajgarh-Nagda-2 feeder connected on this Bus. The mal-operation

of Bus-bar protection for through fault has been taken up with manufacturer and it is

being resolved. Rajgarh S/S is an automated S/S having distributed Bus-bar protection,

where, the Bay Module of Bus- bar protection is also used for LBB protection. The Bus

Bar protection scheme is REB 500 of ABB make.

All the lines were restored by 11:00hrs of 17.06.09.

Committee observed that necessary corrective actions have already been

taken to avoid the undesirable tripping. However PGCIL may take up the matter

with the manufacturer for necessary corrections in the Bus Bar differential

scheme.

ITEM NO. 3: Tripping of lines / ICTs:

The incidences of tripping of lines and ICTs during the period 01-04-2009 to 30-06-

2009 were discussed during the meeting.

Observations of the committee are enclosed at Annexure –3.

ITEM NO. 4: Protection related recommendations on Grid Disturbances in Western

Regional Grid on 25.2.2007 at 1634 hours and 28.2.2007 at 13:11 hours:

Protection related recommendations of the Enquiry Committee on Grid

Disturbances in Western Regional Grid on 25.2.2007 at 1634 hours and 28.2.2007 at 13:11

hours were reviewed during the meeting and the present status regarding implementation of

recommendations is placed at Annexure-4.

ITEM NO. 5: Other points:

5.01: Configuration of direct trip PLCC protection scheme for 220kV lines

emanating from PGCIL S/Ss to utilities.

PGCIL vide their letter No WRTS/O&M/R/141/526 Dt.06.05.09 have informed that the

commissioning of direct trip PLCC scheme is still pending from CSEB end on the 220kV

Urla, 220kV Bhilai, 220kV Bhatapara, 220kV Khedamara, 220kV Surkhi and 220kV Suhela

lines emanating from Raipur and Bhatapara S/S of Powergrid.

Executive Engineer (P) WRPC stated that matter has been taken up with

CSPTCL.

5.02: Testing rectification of the protection schemes at 220kV Ponda S/S:

PGCIL vide their letter No WRTS/O&M/R/141/526 Dt.06.05.09 have informed

that on 31.01.09, 03.03.09 and 10.04.09 tripping occurred on 220kV Mapusa-Ponda line-2.

On all the occasions the fault was beyond the line and the respective protection schemes at

Ponda S/S did not clear the fault. The fault was sensed by protection at Mapusa S/S of

POWERGRID in zone-2/zone-3 timings and the fault current was fed from Mapusa S/S for

that much duration.

During the 105th meeting Goa Electricity Department representative told that

necessary corrective actions would be taken at their end and the compliance would be

communicated by the next PCM

Executive Engineer (P) WRPC stated that the representative of Goa Electricity

Department is not present for this meeting and hence the matter may be taken up in the

next PCM for discussion.

5.03: Revision of settings of df/dt UFLS relays in WR grid

In continuation with the discussion in the 104th meeting, it was decided that the data

received regarding mal operation of the df/dt relays would be analyzed by WRPC.

The details of the mal-operations of df/dt relays from GETCO and MSETCL were

received by WRPC. Other constituents may also please submit the data regarding mal

operation of the df/dt relays.

Committee observed that due to reconfiguration of the algorithm for detection of

fall of df/dt by the relay manufactures as discussed during earlier PCM meetings, there

has been considerable reduction in the mal operation of these relays. As such this issue

may now be closed and in case mal operation starts increasingly, it can be again taken up

PCM.

5.04: Non-availability of Event Logger at 400kV state owned sub-stations at Nagda,

Indore, Bina Padghe, Kolhapur, Koradi, Chandrapur, Dhule and Bhilai.

During 104th PCM, PGCIL had informed that Event Loggers at some of the 400kV

state owned Sub stations, namely Nagda, Indore, Bina of MPPTCL, Padghe, Dhule,

Kolhapur, Koradi, Chandrapur of MSETCL and Bhilai of CSPTCL are not provided. PGCIL

have requested for early installation of Event Loggers at these stations.

MPPTCL representative in earlier meetings had informed that event loggers for

Nagda, Indore and Bina S/S were under procurement process. However the representative

present for 105th PC meeting told that there is no plan of procurement of event loggers for the

above S/S’s.

MPPTCL representative clarified that event loggers available in the numerical

relays as a built in feature, and GPS synchronized clock are being used for logging the events

at all the above S/S’s, hence they are not initiating the procurement process for separate

event loggers for the above S/Ss.

Members of the committee felt that the numerical relays with event loggers as a

build in feature have limited inputs and it can record the events associated with the respective

feeders/elements only and it would not record the external events occurring in the S/S which

are required to be recorded for post fault anaysis of occurrences. Hence a separate event

logger is required to be installed so that all the events occurring required for post fault

analysis of an occurrence in the S/S can be recorded.

MSETCL representative informed that event logger for Padghe and Kolhapur and

Dhule has been commissioned. Further the event loggers at Koradi, Chandrapur and

Khaparkheda have been provided, but unit outages from the generating stations is awaited for

incorporating the events of generating units. MSETCL and MSPGCL representatives agreed

to co ordinate for the same.

5.05: Pending SOE connections and erroneous data in SCADA.

The matter was first discussed in the 102nd PCM, with reference to the pending

SOE connections it was opined that the constituents should confirm the availability of

hardware at RTU’s for incorporating the extension of MTR contacts to the SOE inputs of the

RTU, in addition to the CB contacts which are also required to be transmitted.

During 105th PCM, committee felt that, WRLDC may circulate the list of those

locations from where erroneous data is received and the locations where SOE connections are

yet to be established at the earliest so that corrective actions could be taken up by constituents

and the progress of the same could be monitored.

WRLDC representative told that the list had already been circulated to the respective

state LDCs. However it was appropriate to give this data to the PCM members for necessary

action. He further told that in view of MTR contacts being used by some of the constituents

as inputs for the SOE connections, all the constituents may incorporate MTR contacts only

for SOE connections.

Committee agreed for making MTR contacts to be input for SOE connections to

maintain uniformity and also to correct SOE connections accordingly.

5.06: Review on the existing protection manuals and creating uniformity in the

settings of the modern protection relays.

It was decided in the 103rd PCM that the protection manual prepared by WREB and

referred by the protection engineers is around 10 years old and needs to be reviewed in line

with the present relaying technology. A copy of the WREB protection manual was circulated

amongst the members of the PCM vide letter No.Prot./Prot.Manl/2009/WRPC-3829 Dtd.

21.04.09 so that the same can be taken up for discussions, in this meeting.

Committee discussed the comments forwarded by MSETCL and PGCIL WRTS-

II on Chapter-I “Transmission Line Protection” of the WREB protection manual and

general approach that needs to be formulated/addressed. It was decided that detailed

discussion on this matter would be taken up in the next PCM.

5.07: Problem in Bus bar protection scheme at Korba (W) CSPTCL S/S.

NTPC vide their letter KS/EM/ETL/2405/615109/285 Dtd.05.05.09 have informed that

NTPC Korba and CSPTCL Korba(W) substations are connected with a 400kV line of line

length 14Km. On 04.05.09 at 02:51hrs bus fault occurred (one of the CT of inter connecting

transformer blasted) at CSPTCL end. The NTPC Korba- CSPTCL Korba (W) line tripped in

Zone-2 from NTPC Korba end, thus feeding the fault current of around 14KA for the timing of

Zone-2. Inter trip or direct trip signal was also not received from Korba (W) S/S. Similar fault

had occurred at CSPTCL Korba (W) S/S on 09.09.08 at 11:48 hrs also and was fed for Zone-2

timing from NTPC Korba S/S.

Executive Engineer (P) WRPC stated that matter has been taken up with

CSPTCL.

5.08: Proposal of replacement of ISTS equipment in second phase under R & M by

WRTS-I POWERGRID

POWERGRID vide their letter WRTS-1/O&M/R/142/767 Dtd.19/06/2009, have

proposed to replace following equipments;

(i) Old PLCC panels Type ETI, NSD60-30nos at an estimated cost of Rs.1.5 Crore,

(ii) Replacement of Battery bank at Raipur-4nos, Bhadravati both AC and DC-10nos,

Mapusa-4nos., Boisar-4nos., at an estimated cost of 2Crore.

(iii) Replacement of switchyard equipment (CT’s & CVT’s) due to higher fault level

near Bhilai S/S at an estimated cost of 1.2Crore.

(iv) Replacement of Transformer oil of 13 nos. of converter transformer at HVDC

Bhadravati at an estimated cost of Rs.6Crore

(v) Procurement of long term HVDC spares at an approximate cost of 10Crores

(vi) Procurement of Insulator Washing Equipments with vehicle at an approximate cost

of Rs.1Crore

The details of item at (i) received from PGCIL WRTS-I is enclosed at Annex-5.08.

Committee technically recommended that all utilities including PGCIL may

replace the old PLCC panels (Make ABB Type ETI, NSD60) since a number of mal

operations are reported due to poor performance of these panels installed between 1985

and 1990 and also ABB is not giving service support for these panels. Committee

requested that the details such as sub station wise equipment wise cost breakup, date of

manufacturing and commissioning of the equipment proposed for R & M, location of

installation and the present condition may be submitted by PGCIL WRTS-I so that sub-

Committee may be able to identify the need for R & M of equipment proposed at Sr. nos.

(ii), (iii), (iv), (v) and (vi) above.

Accordingly PCM however recommended that Item at Sr. no.(i) may be taken up

for replacement by PGCIL and the same be put up before the TC sub-Committee/WR

Power Committee for approval.

5.09: Line reactor at Sugen:

NTPC have informed that a 400kV Jhanor-Padghe line of 290km length was having 50

MVAR reactors installed at both ends. Subsequently the line was made LILO at Vapi, without

line reactor at Vapi end and the 400kV Jhanor-Vapi line length reduced to 167km. Further the

400kV Jhanor –Vapi line was made LILO at Sugen (near Surat) without line reactor at Sugen

end. The line length of 400kV Jhanor-Sugen line further reduced to 65km.

Committee felt that though the line length has reduced, the rectors would be

handy in case of a black start condition. Also the present voltage profile in the region is

good so that the reactor can be kept in service. Hence the reactor at Jhanor should be

kept in service in spite of the line length of 65km and no reactor at remote end.

ITEM NO. 6: System disturbance at 400 kV VSTPS Vindhyachal S/S in NTPC

system on 22-07-2008

As discussed during 102nd PCM, a study group comprising of members from WRPC,

WRLDC, VSTPS, Powergrid, GSECL and MSETCL was formed by Member Secretary,

WRPC to look into the matter in detail and analyze the incidence and come up with remedial

measures to avoid such occurrences.

The Study Group has submitted its report and the same was circulated vide letter

No. WRPC/Prot./Vindya/2008-09/5891 Dtd.03.06.09.

Committee discussed the recommendations of the Study Group and felt that the

recommendations needs to be complied by the constituents.

ITEM NO. 7: Date and Venue of the next meeting.

It was decided that the next Protection sub-Committee meeting (107th) will be hosted

by TATA POWER, in November 2009, wherein system disturbances for the period

01/07/2009 to 30/09/2009 will be discussed. Exact date and venue will be communicated

separately.

ITEM SA-8 : Wide Area Measurement System (WAMS) in Western Region.

In the 10th WRPC meeting POWERGRID proposed to take up a project of WAMS for

the Western Regional Grid and it was decided that the matter should be discussed in technical

forum of WRPC.

Accordingly the matter was discussed in the 105th PCM, wherein Prof. S.A.Soman

gave a detailed presentation on the WAMS technology and POWERGRID gave a

presentation on the smart grid project using WAMS technology proposed to be funded by

CSIR and having TCS, IIT Mumbai, TATA POWER and POWERGRID as partners.

It was also proposed that the cost of Rs 8.67 Crores be shared by the constituents.

In the 105th PCM, the sub-Committee had observed the following: -

(i) It was generally felt that there was not adequate clarity regarding the project

such as details of breakup of cost, role and responsibilities of the partners,

technical details etc.

(ii) Some time is required to go through and assimilate the presentations so that

they would come up with their comments.

Subsequently Member (PS), CEA took a meeting on 21.07.2009 with CSIR, CPRI and

PGCIL to sort out the issue of duplication of R&D efforts by different entities in the Power

Sector on implementation of the WAMS project. A copy of the minutes was circulated

amongst the WRPC members vide Letter No. WRPC/Comml.-I/4/Corr./2009-1005 Dtd. 20th

August 2009.

Committee discussed the matter and commented as follows,

1. The PCM appreciated the need to take up the WAMS project on regional basis

initially as Pilot Project.

2. MSETCL along with rest of WR constituents might participate in the

implementation process of WAMS project to be implemented initially as

Regional Pilot project (funded by CSIR with participation by PGCIL, TCS, TPC

and IIT-Bombay) as proposed in the 10th WRPC meeting.

3. MSETCL informed that MSETCL had already taken up WAMS project in

MSETCL grid on pilot basis in association with CPRI-Banglore and IIT-Kanpur

and have installed PMUs at some selected locations. It was intimated that PMU

data from 400kV Padghe, Bableshwar, Kalwa and 220kV Trombay station is

being acquired at SLDC-Kalwa and that MSETCL would, however, implement

the above Pilot project initiated by them in their State on independent basis.

A presentation on the present status of the WAMS project in the Maharashtra

State was given by MSETCL representative. The copy of the presentation is

enclosed at Annex SA-8

4. As informed by PGCIL that a similar Pilot project for implementation of WAMs

has been agreed in Northern Region, the sub-Committee requested that PGCIL

may provide WRPC the details, their experience and present status on

implementation of the same.

5. The sub-Committee members felt that the scheme may require certain

modifications so that the PMU data is available to the constituents of WR, which

is presently not envisaged in the scope of proposed regional pilot project. This

might therefore necessitate certain alterations in the data routing and inclusion

of new PDCs due to reconfiguration of the route / components with additional

cost involvement.

As the function-wise cost-break up for the given total estimated cost of Rs 16.75

Crores for the project (out of which estimated cost of Rs 8.76 Crores is to be

shared by WR constituents) and information related to data routing, extent of

data sharing by the participating agencies, technical capability covered under

existing scope of the proposed Pilot project could not be provided by PGCIL on

the day of 106th PCM meeting, PGCIL agreed to furnish the same to WRPC

shortly as requested by the sub-Committee along with total cost estimate

inclusive of additional cost involved, if any, on account of reconfiguration of the

route / components to make PMU data available to the constituents of WR .

6. PGCIL would furnish replies to the queries raised by Madhya Pradesh and

Gujarat in the meeting raised vide their letters Nos 1257 dated 4.8.2009 and 1043

dated 12.8.2009 as included in the supplementary agenda notes of the 106th PCM.

7. The locations identified for providing the envisaged 25-30 PMUs under the Pilot

Project in the Western Region in the scheme under the proposed Pilot Project,

would be intimated by PGCIL.

8. Protection Sub-Committee of WRPC recommended that a Special Protection

Group may be formed with suitable representation from WR constituents to

discuss the above issues and the out come of the same will be put up to TCC/WR

Power Committee for further consideration of the matter by the Committee.

ANNEX-I LIST OF PARTICIPANTS

106th Protection Committee Meeting held on 1st & 2nd September 2009 at W.R.P.C. Mumbai.

GSECL (Gujarat State Electricity Corporation Limited)

Shri U.D. Adharyu Superintending Engineer (Testing) Vadodara

GETCO (Gujarat Energy Transmission Corporation Limited)

Shri J.N. Pancholi Executive Engineer (Testing) Vadodara

IIT Mumbai

Dr. S.A.Soman Professor - Special invitee Shri Gopal Gaijzr

MAHAGENCO (Maharashtra State Power Generation Company Limited)

Shri A.K.Patil Superintending Engineer (T/F)

MSETCL (Maharashtra State Electricity Transmission Company Limited)

Shri V.M.Latey Chief Engineer (Special Project)-Special Invitee Shri S.G.Kelkar Chief Engineer (Load Dispatch-Special Invitee Shri B.A.Sawle Superintending Engineer (TCC), Aurangabad Shri D.J.Kolhe Dy. Executive Engineer, Load Dispatch Kalwa Shri S.S.Rajurkar Dy. Executive Engineer, H.O. Bandra Shri D.P.Nandanwar Dy.Executive Engineer (Testing), Vashi. Shri A.R. Kulkarni Assistant Engineer, H.O. Bandra

MPPTCL (Madhya Pradesh Power Transmission Corporation Limited)

Shri A.K.Shrivastava Executive Engineer (TCC), Indore

NPCIL (Nuclear Power Corporation of India Limited)

Shri V.M. Daptardar SME (E) TAPS Shri A.K.Singh MS TAPS Shri A.N. Thakur Scientiffic Officer TAPS-3&4

NTPC

Shri Jitendra Tewari D.G.M. (EMD) Vindhyachal

PGCIL (Power Grid Corporation of India Limited)

Dr.Sunita Chauhan Chief Manager , LD & C. Gurgaon -Special invitee

Shri Anand Dubey Manager WRTS-II, Vadodara Shri R. A. Wadyalkar Dy. Manager WRTS-I, Nagpur

REL (Reliance Infra Ltd.)

Shri S.S.Joshi Manager (E), TPS Dahanu Shri M. R. Waingankar Manager (Trans), Mumbai.

TPC (Tata Power Company)

Shri J.D.Shrotri Deputy G.M.(Engg) Shri T. Murali Krishna Chief Manager, Trombay, Mumbai Shri M.V. Kini Assistant General Manager

WRLDC (Western Regional Load Dispatch Centre)

Shri M.G. Raoot Executive Director (WRLDC) Shri P. Pentayya AGM (WRLDC) Shri P.Biswas Manager, WRLDC Mumbai

WRPC (Western Regional Power Committee)

Shri Manjit Singh Member Secretary Shri M.R.Singh Superintending Engineer (P) Shri S.G.Tenpe Superintending Engineer © Shri O.P.Singh Superintending Engineer (O) Shri Satyanarayan S. Executive Engineer (P) Shri P.D.Lone Assist.Dir.-I(P)

ANNEXURE-3

TRIPPINGS OF LINES / ICTS

Sr. No. NAME OF S/S Name of line/ICT SYSTEM /Provision

of A/R (Yes/No)

Tripping Restoration REASON

Date Time Date Time 3.01 400kV Jabalpur 400kV Jabalpur-

Itarsi#3 PGCIL (Y) 01.04.09 0:37 01.04.09 0:37

A/R successful on Y-N transient fault.

3.02 400kV Padghe 400kV Padghe-Bableshwar-I

MSETCL (Y) 01.04.09 4:09 01.04.09 5:09

R-E, Zone-1 fault. Patrolling done no fault found Line tripped from both end. Transient nature of fault. Problem in A/R

3.03 400kV Nagda 400kV Nagda-Dehgam#1 PGCIL

(Y) 01.04.09 19:23 01.04.09 20:48 Mal operation of PRD at Dehgam due to high oil level inReactor.

3.04 400 KV Korba 400 KV Korba-Bhilai # 1 PGCIL

(Y) 04.04.09 11:42 04.04.09 11:49 Line tripped from Korba end. Wiring problem, during new main breaker commissioning

3.05 400kV Padghe 400kV Padghe-Lonikand MSETCL

(Y) 06.04.09 9:01 06.04.09 10:04 Bus fault at Lonikand end. Linetripped at Padghe end on receiptof D/T.

3.06 400kV C'pur 400kV C'pur-Parli#1 MSETCL (Y) 06.04.09 12:04 06.04.09 12:04

Transient Y-N fault. A/R successful at both ends.

3.07 400kV Indore 400kV Indore-Asoj#1 PGCIL

(Y) 06.04.09 13:11 06.04.09 14:00 Transient R-N fault.

3.08 400kV Koradi 400kV Koradi-Akola MSETCL

(Y) 06.04.09 16:29 06.04.09 18:51 Transient B-N fault. A/R & L/O at Asoj end.

3.09 400 KV Boisar 400 KV Boisar-Padghe PGCIL

(Y) 08.04.09 17:50 08.04.09 18:06 Line tripped due to Direct Trip received from Padghe end due to DC earth leakage at Padghe.

3.10 400 KV Raipur 400 KV Raipur-Sipat # 1 PGCIL

(Y) 08.04.09 20:26 08.04.09 21:09 Line tripped on Y-E fault. F.L=71. 5 Km from Raipur. A/Rattempted but failed.

3.11 400kV Khadwa 400kV Khadwa-Rajgarh PGCIL

(Y) 09.04.09 6:33 09.04.09 6:38 O/V stage-I operated at Rajgarh S/S.


(Y) 09.04.09 00:16 09.04.09 01:51 Line tripped on Y-E fault. F.L=76 Km from Raipur. A/R attempted but failed.


(Y) 09.04.09 01:51 09.04.09 02:01 Line tripped on Y-E fault. F.L=76 Km from Raipur. A/R attempted but failed.

3.14 400 KV Raipur 400 KV Raipur-Bhatapara

PGCIL (Y) 09.04.09 01:51 09.04.09 02:46

Line tripped during the chargingof 400kV Raipur-Sipat # 1 due to maloperation of Tie LBB relay. LBB contact problem. Replaced the relay.

3.15 400 KV Raipur 400 KV Raipur -Raigarh # 1 PGCIL

(Y) 09.04.09 04:18 09.04.09 04:18 Line Auto Reclosed on R-phase, 31.5 Km from Raipur.



3.17 400kV Gandhar 400kV Gandhar-Dehgam#2 PGCIL

(Y) 11.04.09 15:21 11.04.09 15:56 Persisting R-N fault. A/R attempted but failed.

3.18 220 KV Korba(E)

220 KV Korba(E) - Budhipadar # 3 PGCIL

(Y) 12.04.09 06:48 12.04.09 07:52 Line tripped on C-Ph to Earth fault.

3.19 220 KV Korba(E)

220 KV Korba(E) - Budhipadar # 3 PGCIL

(Y) 12.04.09 21:34 13.04.09 01:25 Line tripped on C-Ph to Earth fault.

3.20 400 KV Kasor 400 KV Kasor-Chorania GETCO

(Y) 13.04.09 15:44 13.04.09 15:50 B-Ph. CVT failed at Chorania S/s end.Replaced the same.

3.21 400 KV Kolhapur

400 KV Kolhapur - Mapusa # 1 PGCIL

(Y) 13.04.09 16:38 13.04.09 16:48 Line tripped on Rph - Earth fault at 79.26 kM from Mapusa.A/R attempted but failed.

3.22 400 KV Kasor 400 KV Kasor -Gpec GETCO

(Y) 15.04.09 10:25 15.04.09 10:40 Mal operation of PLCC at GPEC end.

3.23 400kV Jabalpur 315MVA ICT#1 PGCIL

(Y) 15.04.09 14:07 15.04.09 15:12 Backup protn (O/C LV side)optd at 220kV MPPTCL S/S

3.24 400kV Itarsi 400kV Itarsi-Indore#1 PGCIL

(Y) 19.04.09 13:40 19.04.09 15:12 Bus Bar Protection mal operatedat MPPTCL Indore S/S.

3.25 400 KV Korba 400 KV Korba-Vindhyachal # 1

PGCIL (Y) 21.04.09 13:02 21.04.09 18:26

Line tripped on R-Phase to earthfault due to burning of farm fields near NTPC,Vindhyachal S/S boundary.

3.26 400 KV Asoj 400 KV Asoj-Indore 2 GETCO

(Y) 23.04.09 17:35 23.04.09 18:02

Line reactor differential trip at indore S/s. For a line fault of transient nature the diff protn. Mal operated.

3.27 400kV Itarsi 400kV Itarsi-Indore#2 PGCIL (Y) 24.04.09 12:36 24.04.09 12:52

Persisting Y-N fault.A/R L/O.

3.28 400 KV Boiser 400 KV Boiser - Vapi PGCIL

(Y) 24.04.09 11:33 24.04.09 11:33 Line auto reclosed sucessfullyon B - Phase to earth fault. F/L=61.1km from Boiser end.




(Y) 26.04.09 9:45 26.04.09 9:45 Transient R-N fault. A/R successful at both ends.

3.31 400kV Koradi 400kV Koradi-Akola

MSETCL (Y) 27.04.09 6:02 27.04.09 7:06

L/O trip on receipt of DT signalat Koradi end. The line tripped on O/V stage-I (setting 110% 5sec.) at Akola end & DT was sent to Koradi

3.32 400kV Satpura 400kV/220kV ICT

MPPTCL 30.04.09 20:30 02.05.09 20:04

ICT tripped from 400kV & 220kV sides on B/U instantaneous Y phase, due to failure of Y ph. CVT of 220kV Sarni-Pandhurna line.

3.33 400 KV Korba 400 KV Korba - Bhilai # 2 PGCIL

(Y) 30.04.09 10:10 30.04.09 10:36 Line tripped at Bhilai end without any indiacation. DC leakage suspected.

3.34 400kV Satna 400kV Satna-V'chal#1 PGCIL

(Y) 03.05.09 5:36 03.05.09 20:37 O/V stage-I optd., at VSTPP end.

3.35 400kV Itarsi 400kV Itarsi-Indore#2 PGCIL (Y) 04.05.09 16:47 04.05.09 17:14

Persisting B-N fault.

3.36 400kV Padghe 315MVA, 400/220kV ICT-2 MSETCL

(Y) 04.05.09 16:54 04.05.09 17:43 Diff protection operated. On inspection 33kV cable of tertiary wdg. found damaged.

3.37 400 KV Korba 400 KV Korba - Korba (W)

PGCIL (Y) 04.05.09 02:51 04.05.09 04:50

Line tripped at Korba end on B/B protection operated at Korba (W),due to failure of 400kV Rph CT of ICT at Korba (W).

3.38 400 KV Bhilai 400 KV Bhilai-Korba # 1 PGCIL

(Y) 05.05.09 10:01 05.05.09 10:25 Line tripped due to receive of Direct Trip command from Korba end.PLCC maloperation

3.39 400 KV Bhilai 400 KV Bhilai-Koradi

PGCIL (Y) 05.05.09 10:01 05.05.09 10:25

Line Tripped due to Direct Tripreceived from Korba end, as Korba-1 & Koradi line are terminated in the same dia at Bhilai.Main Bkr. of Koradi linewas out at Bhilai. PLCC maloperation

3.40 400kV Kharghar

315MVA, 400/220kV ICT-1 MSETCL

(Y) 06.05.09 15:55 06.05.09 18:48 ICT tripped on the operation of PRV. On inspection PRV microswitch found faulty

3.41 400 KV Wardha 400 KV Wardha - Akola #1 PGCIL

(Y) 07.05.09 07:04 07.05.09 10.14 Line tripped on over voltage stage-I.

3.42 765 KV Seoni 765 KV Seoni - Wardha # 1 PGCIL

(Y) 07.05.09 07:04 07.05.09 08:30 Line tripped on Over Voltage Protection Stage - 1.

3.43 400 KV Korba 400 KV Korba - Bhilai # 1 PGCIL

(Y) 07.05.09 16:26 07.05.09 16:45

Line Tripped only at Bhilai end on receipt of Direct trip signal from Korba end. PLCC mal opeartion

3.44 400 KV Ranchi 400 KV Ranchi - Sipat # 1

PGCIL (Y) 08.05.09 18:00 08.05.09 18:40

Line successfully auto-reclosed from Ranchi end on R - E transient fault at 115 Km from Ranchi, but tripped at Sipat endonly

3.45 400kV Kalwa 400kV Kalwa-Padghe-1

MSETCL (Y) 09.05.09 14:05 09.05.09 14:58

Y-E, Zone-2 fault. While carrying out hot line washing, Y-ph conductor snapped the insulator resulting the flashover of Y-ph conductorat 51.1KM from Kalwa end

3.46 400 KV Raipur 400 KV Raipur-Bhilai # 1 PGCIL

(Y) 10.05.09 04:09 10.05.09 05:05 Line triped on Overvoltege stage-1 protection. CVT problem

3.47 400kV Seoni ICT # 1 (400/220KV) at Seoni

PGCIL (Y) 11.05.09 22:00 12.05.09 00:27

ICT tripped on earth fault protection along with tripping o220KV Seoni - Seoni # 1&2 lines (MPSEB) on line fault as fault was not cleared in 220KV lines.

3.48 400kV Nagothane

400kV Nagothane-Padghe-2 MSETCL

(Y) 12.05.09 4:40 12.05.09 12:33 R-E, Zone-2 fault. Earthwire found broken at 116KM from Nagothane end.

3.49 400 KV Wardha 400 KV Wardha - Akola # 1 PGCIL

(Y) 12.05.09 13:13 12.05.09 13:35

Line tripped at Wardha end only, on receipt of Direct trip command due to PLCC maloperation.


(Y) 12.05.09 15:24 12.05.09 16:07

Line tripped at Wardha end only, on receipt of Direct trip command due to PLCC maloperation.


(Y) 13.05.09 17:59 13.05.09 18:24 Transient B-N fault.



3.53 400kV Jabalpur 400kV Jabalpur-Itarsi#2 PGCIL

(Y) 14.05.09 15:03 14.05.09 15:21 Persisting R-N fault.


(Y) 14.05.09 15:03 19.07.09 20:17 18 Towers collapsed.


(Y) 14.05.09 15:03 30.05.09 19:58 18 Towers collapsed.


MSETCL (Y) 14.05.09 19:16 15.05.09 1:30

Transient B-N fault. Line was recharged at 21:57 & 22:27hrs. From Koradi end but tripped onreceipt of DT signal from Akolaend because of O/V protn optd. at Akola.


(Y) 14.05.09 07:06 --- --- Line tripped on over voltage. Kept out due to system constraints.


(Y) 14.05.09 07:06 14.05.09 08:00 Line tripped on over voltage


(Y) 14.05.09 19:16 15.05.09 12:12

Line tripped on DT receive at Wardha end. PLCC maloperation




(Y) 15.05.09 16:45 15.05.09 16:56 Persisting B-N fault.

3.62 400kV Bina 400kV Bina-Nagda#2 PGCIL (Y) 15.05.09 17:49 15.05.09 18:06

Persisting R-N fault.

3.63 400 KV Raipur 400 KV Raipur-Bhilai # 2 PGCIL

(Y) 15.05.09 18:23 15.05.09 18:23 Line A/R successfully on R-E

fault.F.L=14Km from Raipur



3.65 400kV V'chal 400kV V'chal-Jabalpur#1 PGCIL

(Y) 17.05.09 3:57 17.05.09 5:05 Maloperation of Reactor Backuprelay (RAKZB) at VSTPP end.



3.67 400kV Koradi 400kV Koradi-Bhusawal MSETCL

(Y) 17.05.09 18:04 17.05.09 18:04 Transient Y-N fault. A/R successful at both ends.

3.68 400kV Chandrapur

400kV C'pur-Parli#2

MSETCL (Y) 17.05.09 18:22 17.05.09 20:21

Transient B-N fault. Trip ckt faulty indication appeared after tripping at Koradi end. Problemwas located in the Gas Pressure Switch. The line charged through TBC 1.

3.69 400 KV Raigarh 400 KV Raigarh-Rourkela # 2 PGCIL

(Y) 17.05.09 16:07 17.05.09 19:54

Line tripped on earth fault. F/L = 284 km from Raigarh.TEE diff. prot. Optd at Rourkela end

3.70 400kV Padghe 400kV Padghe-Nagothane-1 MSETCL

(Y) 18.05.09 13:47 18.05.09 17:55

B-E, Zone-1. B-ph decapping observed at loc.No.5

3.71 400kV Padghe 400kV Padghe-Bableshwar-1 MSETCL

(Y) 19.05.09 16:12 20.05.09 3;46

YB, Zone-1. Patrolling done no fault found, Transient nature of fault

3.72 400 KV Raipur 400 KV Raipur-B'wati # 2 PGCIL

(Y) 19.05.09 15:30 19.05.09 15:58 Line tripped on B-E Fault at 265.6 Km from Bhadrawati.A/Rsuccessful at Raipur end



3.74 400kV Padghe 400kV Padghe-PGCIL (Boisar) MSETCL

(Y) 21.05.09 8:22 21.05.09 10:40

B-E, Zone-1. Patrolling done, no fault found Transient nature of fault.

3.75 400 KV Boisar 400 KV Boisar-PadghePGCIL

(Y) 21.05.09 09:24 21.05.09 09:41 Line Tripped on B-E fault . Fault in Z2 from Boisar, and nocarr. Received at Boisar




(Y) 22.05.09 17:20 22.05.09 17:20 Transient B-N fault. A/R successful at both ends.



3.79 400 KV Chorania

400 KV Chorania-Amreli GETCO

(Y) 24.05.09 0:30 25.05.09 0:57 Due to problem in R - ph CVT -WS Make replaced.


(Y) 24.05.09 12:30 02.06.09 22:10 3 Nos Tower collapsed.


(Y) 24.05.09 12:30 02.06.09 22:36 3 Nos Tower collapsed.


Persisting B-N fault.

3.83 400 KV Raipur 400 KV Raipur - Sipat # 2 PGCIL

(Y) 24.05.09 16:51 24.05.09 17:25

Line A/R successfully at Raipurend but tripped at Sipat end on Y-G fault at 136.3 kM from Raipur.





3.86 400 KV Wardha 400 KV Wardha-Akola # 2 PGCIL

(Y) 25.05.09 15:56 25.05.09 17:38 Line tripped on DT received at Wardha end. PLCC maloperation.

3.87 400 KV B'wati 400 KV B'wati-C'pur # 4 PGCIL

(Y) 26.05.09 17:27 26.05.09 17:56

Line tripped at Chandrapur end on B-E fault at 2.8 KM from B'wati end.Auto reclosure successfull at B'wati end.



3.89 400kV Raipur 400kV Raipur-B'wati # 2 PGCIL

(Y) 30.05.09 17:30 30.05.09 17:30 Line A/R successfully on Y-E fault.F.L=26.53 Km from Bhadrawati

3.90 400kV Raipur 400kV Raipur-B'wati # 3 PGCIL

(Y) 30.05.09 17:30 30.05.09 17:30 Line A/R successfully on R-E fault.F.L=29.9 Km from Bhadrawati


Transient R-N fault.

3.92 400 kV B'wati 400 kV B'wati - C'pur # 4 PGCIL

(Y) 31.05.09 16:28 31.05.09 18:02 Line tripped on persistant B - Efault at 2.9 kM from Bhadrawatafter attending A/R at both ends

3.93 400 kV B'wati 400 kV B'wati - C'pur # 3 PGCIL

(Y) 31.05.09 16:28 31.05.09 18:12 Line tripped on persistant B - Efault at 2.9 kM from Bhadrawatafter attending A/R at both ends


(Y) 01.06.09 6:42 01.06.09 7:00 Phase to Phase (Y-B) fault.

3.95 400kV Bhilai 400kV Bhilai-Korba (W) CSPTCL

(Y) 01.06.09 18:31 01.06.09 18:56 Tripped from both end on BN fault. A/R L/O.

3.96 400 KV Raipur 400 KV Raipur - Sipat # 3

PGCIL (Y) 03.06.09 03:45 03.06.09 11:54

Line successfully auto reclosed at both ends on R - E fault at 108 km from Raipur end. Line again tripped on receipt of DT signal due to overvoltage protection operated at Sipat end

3.97 400kvC'pur 400kvC'pur-Koradi MSETCL (Y) 04.06.09 18:28 04.06.09 18:28

Transient B-N fault. A/R successful at both ends.



3.99 400 KV Raipur 400 KV Raipur - Sipat # 1

PGCIL (Y) 04.06.09 00:24 04.06.09 01:53

Line tripped on Y - E fault at 70.7 kM from Raipur. A/R operated successfully, but line tripped due to persistent fault inline.

3.100 400 KV Raipur 400 KV Raipur - Bhilai # 1 PGCIL

(Y) 04.06.09 08:48 04.06.09 10:21

Line tripped with external flash over occurred on B - Phase CT of Main Bay at Bhilai end Bus fault at Bhilai S/S


(Y) 04.06.09 08:48 04.06.09 09:28 Line tripped only at Raipur end in zone-2 for CT external flashover at Bhilai

3.102 400 KV Bhilai 400 KV Bhilai - Korba # 1 PGCIL

(Y) 04.06.09 08:48 04.06.09 09:39 Line tripped only at Korba in zone -2 for CT external flashover at Bhilai

3.103 400 KV Bhilai 400 KV Bhilai - Korba # 2 PGCIL

(Y) 04.06.09 08:48 04.06.09 09:29 Line tripped only at Korba end in zone-2 for CT external flashover at Bhilai


(Y) 04.06.09 15:18 04.06.09 15:18 Line successfully auto reclosedat both ends on B - E fault at 7.89 km from Raipur





3.107 400 KV Raipur 400 KV Raipur-B'wati # 1 PGCIL

(Y) 05.06.09 02:46 05.06.09 02:46 Line successfully auto reclosedat both ends on Y - E fault at 190 km from Raipur


(Y) 05.06.09 14:48 05.06.09 14:48 Line successfully Auto Reclosed at both ends on Y - Efault at 82 kM from Raipur.


(Y) 05.06.09 14:50 05.06.09 14:50 Line successfully Auto Reclosed at both ends on Y - E fault at 82 kM from Raipur



3.111 400 KV Korba 400 KV Korba - Korba (W) PGCIL

(Y) 05.06.09 18:52 05.06.09 19:26

Line tripped because of relay maloperation at Korba end, due to tower collapase of 400KV Bhilai-Korba(W) # 1.

3.112 400kV Padghe 400kV Padghe-Lonikand MSETCL

(Y) 06.06.09 1:54 06.06.09 16:11 Y-E, Zone-1 Y-ph decapping observed at locNo.19

3.113 400kV Nagothane

400kV Nagothane-Padghe-2 MSETCL

(Y) 06.06.09 5:33 06.06.09 6:16 O/V stage-1 Over Voltage = 416KV at Nagothane end




(Y) 06.06.09 08:31 06.06.09 08:31 Auto Reclosure on R-E fault aFault location 133 KM from Bhilai


(Y) 06.06.09 15:33 06.06.09 15:52 Line tripped on Bph to Earth fault at Fault location 199Km from Bhilai.

3.117 400 KV Korba 400 KV Korba-Bhilai # 1

PGCIL (Y) 06.06.09 15:33 17.06.09 21:41

Line tripped due to 3 Towers collapsed at location 88, 89, 90 because of heavy rain and windFault location 159.5 KM from Bhilai.

3.118 400 KV Raigarh 400 KV Raigarh-Rourkela #2 PGCIL

(Y) 06.06.09 17:25 06.06.09 17:25 Auto reclose successful on Y-Efault at Fault location 66 KM from Raigarh.

3.119 765 KV Seoni 765 KV Seoni-Wardha # 1 PGCIL

(Y) 06.06.09 19:03 06.06.09 19:29 Line tripped on over voltage stage-I protection.

3.120 400 KV Wardha 400 KV Wardha-Akola #2 PGCIL

(Y) 06.06.09 19:03 06.06.09 19:44 Line tripped on over voltage stage-I protection

3.121 400 KV Asoj 400 KV Asoj-Chorania-1 GETCO

(Y) 07.06.09 9:05 07.06.09 9:33 Over voltage stage -1 at asoj end.

3.122 400 KV Bhilai 400 KV Bhilai-Koradi line

PGCIL (Y) 08.06.09 11:35 08.06.09 11:49

Line tripped on Y - E fault at 40.2 Km from Bhilai. and , Line successfully A/R at Bhilai end but tripped at Koradi end Main 2 protn found optd on DEF causing L/O. Opn. Of DEFneeds to be discussed.

3.123 400 KV B'wati 400 KV B'wati-C'pur # 4 PGCIL

(Y) 08.06.09 17:14 08.06.09 17:14 Line successfully Autoreclosedat both the ends on B-E fault a7.37 KM from Bhadrawati end.

3.124 400 KV Raigarh 400 KV Raigarh - Rorkela # 1

PGCIL (Y) 10.06.09 20:30 10.06.09 21:31

Line tripped on B - E fault at 243 Km from Raigarh, successfully auto reclosed at Raigarh end,auto reclose unsuccessfull at Rourkela end.


(Y) 12.06.09 15:09 12.06.09 16:24 Prsisting Y-N fault.


(Y) 12.06.09 19:02 12.06.09 19:15 Line tripped on Over Voltage



3.128 400 KV Ranchi 400 KV Ranchi - Sipat # 1 PGCIL

(Y) 13.06.09 18:32 --- ---

Line tripped at Sipat end for Reactor fault at Ranchi. Line kept out due to system constraints.



3.130 400kV Vapi 400kV Vapi-Sugen PGCIL (Y) 15.06.09 4:28 15.06.09 14:20

Prsisting B-N fault.

3.131 400kV C'pur 3x105MVA,400/220kV ICT 2

MSETCL (Y) 16.06.09 9:49 16.06.09 10:02

Spurious tripping due to unknown cause. Investigation done in detail by taking outage, nothing abnormal found. ICT kept under observation.



3.133 400/220kV Raipur

400/220KV ICT#2 PGCIL (Y) 17.06.09 23:08 18.06.09 00:14 ICT tripped on over fluxing.



3.135 400kV Sarni 400kV Sarni-Indira Sagar MPPGCL 18.06.09 17:07 18.06.09 17:40

Line tripped from both end ontransient Y-N fault.

3.136 400 KV Kasor 400 KV Kasor -Gpec GETCO

(Y) 19.06.09 9:18 19.06.09 9:43 After patroling no cause found.

3.137 400kV Khandwa

400kV Khandwa-Dhule#1 PGCIL

(Y) 19.06.09 16:26 16.07.09 21:39 5 nos. Towers collapsed.

3.138 400kV Khandwa

400kV Khandwa-Dhule#2 PGCIL

(Y) 19.06.09 16:26 29.08.09 18:45 5 nos. Towers collapsed.



3.140 400kV Itarsi 400kV Itarsi-Satpura PGCIL (Y) 21.06.09 16:35 21.06.09 18:56

Persisting Y-N fault.

3.141 400kV Sarni 400kV Sarni-Itarsi

MPPGCL 21.06.09 16:40 21.06.09 18:56

Line tripped from both ends on Y-N fault. A/R L/O. Line test charged but tripped on pole discripancy.


Transient Y-N fault.


(Y) 22.06.09 19:20 22.06.09 19:58 Line tripped at Koradi end on receipt of DT on operation of O/V stage-I at Akola.

3.144 400kV Khandwa

400kV Khandwa-Seoni#1 PGCIL



A/R successful on transient YN fault.

3.146 400 KV Vapi 400 KV Vapi-Boisar

PGCIL (Y) 22.06.09 17:33 23.06.09 11:32

Line tripped on B-E fault due toinsulator string failure.F/L= 90.KM from Boisar end.Reclosing attempted but tripped on persistant fault.



3.148 400 KV Wardha 400 KV Wardha-Akola #1 PGCIL



Transient R-N fault. A/R successful at both ends.


Transient B-N fault. A/R successful at both ends.




(Y) 23.06.09 19:05 23.06.09 19:15 Transient Y-N fault.

3.153 400kV Raipur 400/220KV ICT # 1 PGCIL (Y) 24.06.09 05:16 24.06.09 20:01 ICT tripped on over fluxing.







Persisting R-N fault.

3.158 400 KV Korba 400 KV Korba - Korba (W) PGCIL

(Y) 25.06.09 02:35 26.06.09 21:46 Line tripped due to failure of 'Rphase CT at Korba (W)CSEB end.


3.160 400 KV Bhilai 400 KV Bhilai - Seoni PGCIL

(Y) 25.06.09 15:38 25.06.09 18:35 Line tripped due to operation ofReactor Protection at Bhilai end

3.161 400 KV Bhilai 400 KV Bhilai - B'watiPGCIL

(Y) 25.06.09 18:32 25.06.09 18:32

Line successfully Auto reclosed at both ends on R - E fault at 142.2 kM from Bhadrawati end.

3.162 765KV Seoni 765KV Seoni - Wardha # 1 PGCIL



Persisting Y-N fault.

3.164 765KV Seoni 765KV Seoni - Wardha # 1 PGCIL



(Y) 26.06.09 19:05 --- --- Line tripped on over voltage. Line kept out due to system constraints.


(Y) 28.06.09 17:00 28.06.09 17:00 A/R successful on transient B-N fault.


MSETCL (Y) 29.06.09 3:14 29.06.09 6:00

Line tripped at Koradi end on receipt of DT on operation of O/V stage-I at Akola. The O/V occurred after tripping of AkolaBhusawal line due to fault in wave trap.


(Y) 29.06.09 03:13 --- --- Line tripped on over voltage. Line kept out due to system constraints.


(Y) 30.06.09 19:20 30.06.09 20:10

Line tripped on R - Earth Fault at 5.135 kM from Bhilai. A/R unsuccessful due to maloperation of REL 531 relay.

Annexure –4 Present status on recommendations pertaining to Protection of Inquiry Committee on grid disturbances of 25.02.2007 and 28.02.2007 Sr no

Recommendations

I

Decisions and Suggestions of PC for implementing the recommendations

II

Status

III

i) Both Main- I and Main –II protection on 400 kV Padghe- Nagothane Ckt-I is provided by ABB make REL 521 relays with same characteristic and settings thereby defeating the purpose of providing selectivity and discrimination of the fault. In line with Section 2 of CBIP Publication 274 of November 1999, Main-I and Main-II protection should be of different types and not necessarily of different make.

It was decided in the 99th and 100th PCM that as a first step all constituents shall identify and intimate such feeders where both Main-I and Main-II protections having similar characteristics are provided. Also wherever possible constituents shall swap the relays and achieve the objective of providing Main-I and Main-II protections having different characteristics of operation. Committee will review the progress made by constituents with regards to these identified feeders. It was decided in the 104th PCM that constituents would furnish details of Main-I & Main-II relays for all 400kV lines to WRPC which will then be discussed in next PCM.

MSETCL intimated that on 400 kV Padghe – Nagothane ckt-I, Main-I and Main-II protections have been provided with different characteristic and settings at Nagothane and Padghe end. REL 521 Main-I relays provided at Padghe end replaced with Siemens make relay on 13th Sept 08. In pursuant of the decision of the PC, MSETCL had submitted the information regarding the feeders having similar Main-I and Main-II characteristics, in respect of all Circles and agreed to explore the possibility of swapping relays to implement this recommendation. MPPTCL representative informed that they have implemented this recommendation. PGCIL have implemented the recommendation except on 400kV Indore-Asoj line which will be done by Sept.09 and they have submitted the details of Main-I & II relays. GETCO have implemented the recommendation except two fdrs. Viz. 400kV Chornia-Hadala & Chornia-Jetpur.

ii) The Committee observed that distance relay REL 521 does not have the feature of recording switching off of auxiliary DC supply to the relay as an internal event among recording of other related relay supervision parameters. For the grid disturbance of 25.2.2007, the time of switching off of DC auxiliary supply was very crucial information, which was not available. The possibility of incorporating the time of switching off of DC auxiliary supply as an internal event recording may be taken up with the manufacturer.

a) As agreed in 98th PCM MSETCL took up the matter of incorporating the time of DC supply off to relay as an internal event with M/S ABB.

b) For future procurement this requirement may be added in the specification of relays itself.

c) Committee in its 100th PCM suggested that as an alternative watch dog contacts available on fascia can wired up to log as an event on SER provided in sub -stations.

d) In 101st PCM the Committee suggested

A) ABB have intimated that whenever DC supply is switched off, relay can not function and hence event can not be stored “DC off “ as an internal event in a memory, so suggestion made by enquiry committee can not be implemented. Committee felt that reply of M/s ABB was satisfactory and recommended that suggestions made in 100th and 101st PCM’s to overcome the problem may be implemented.

In 104th PCM MSETCL informed that at Koradi, Padghe, New Koyna & Aurangabad S/S this feature has been implemented through SMS. At Dhule, Lonikand, Parli & Chandrapur

that in case SER is not provided in the S/s it is suggested that, wherever possible DC supply OFF contacts of Main-I & Main-II relays can be wired to Main-II & Main-I relays respectively, thus DC supply OFF event of both the protection schemes is stored in either of the relay.

S/S’s it will be implemented by Dec 09. In 104th PCM PGCIL informed that the feature have been incorporated in the event logger (stand alone) with GPS stamping. GSECL informed that this feature is incorporated in SER’s In 104th PCM GETCO informed that this feature has been incorporated in SER’s. In 104th PCM MPPTCL informed that the feature will be incorporated in event loggers and it is under procurement stage. The information regarding the compliance of this recommendation has been submitted by Nashik and Vashi Circles of MSETCL, PGCIL and NPCIL

iii) The triggering of disturbance recorders at Padghe substation gets initiated only with the relay operation. Therefore, disturbance recording would not take place if the relay has not operated. The Committee recommends that the DRs should also have analog triggering signal from voltage/current/frequency threshold to ensure generation of DR data.

Committee discussed and recommended the following threshold values for current and voltages to trigger DRs during 100th PCM

a) High Voltages:-150 % 0f nominal voltage.

b) Low Voltages:- 70% of nominal voltage without any intentional time delay.

c) Over Current:-150% of rated

secondary current with time delay of 1 sec can be given for triggering DRs.

A) In 101st PCM MSETCL Nasik and Vashi informed that they have implemented the decisions in most of S/Ss, and constituents were requested to follow the suite.

B) Till the SMS is implemented in MSETCL, MSETCL Nagpur Circle may adopt a time delay of 100msec for high and low voltage triggering of DRs.

C) In 105th PCM GETCO informed that they have implemented the decisions except 400kV Asoj-Indore 1 & 2 lines.

D) In 105th PCM PGCIL informed that they have implemented the decisions in all the S/S. However during 106th PCM the representative told that due to overflow of data the Under Voltage triggering have been disabled.

E) In 104th PCM MPPTCL has informed that they have implemented. The settings will be confirmed.

Nasik and Vashi circles of MSETCL, NPCIL and WRTS-2 have submitted data regarding this recommendation.

iv) The Committee expresses its concern that 400kV Padghe substation does not have compatible device to download the disturbance data recorded

Protection Committee stressed the importance of compatible data download facility and requested constituents

MSETCL informed that data down loading facility from numerical relays has been included in their Substation Monitoring

from the memory of the numerical distance relays installed on 400kV lines. The Committee recommends that every sub-station having numerical relays be provided with compatible data downloading device to facilitate analysis of the vital information.

to arrange for same expediously.

Schemes (SMS) and would be made available. All Circles of MSETCL had provided laptops at all the S/s for downloading the data. GETCO has confirmed that data down loading facility has been made available at all the S/s. PowerGrid has confirmed that data downloading facility is available at all the S/s.

All other constituents were requested to follow suite and intimate the progress.

CSEB informed that this recommendation is in process of implementation and will be complied. MPPTCL informed that this facility has been included in ERPC (Enterprising Resource Planning Scheme), which is under tendering process. In 104th PCM MPPTCL informed that manual downloading facility is made available at S/S’s. The status of this recommendation has been submitted by Nasik & Vashi Circles of MSETCL, WRTS-2 and NPCIL.

v) The simulation studies indicate that the distance protection scheme provided on some lines are under-reaching due to in-feed effect. Protection Committee of WRPC may look into this aspect and review the settings of 400 kV lines considering in-feed.

In 98th PCM it was agreed that Zone –III settings considering in-feed effect is to be arrived after due study and on case to case basis. It was suggested that each state should initiate studies starting with any one station in their system results of the study may be put up to Committee for further discussions. During 104th PCM Constituents were requested to carryout study for one of the 400kV S/S in their system and put up to committee for further review. MSETCL was requested to pursue with the protection review group to take up the issue for Padghe S/S.

MSETCL informed that protection review group has been formed and the group will take up this issue as a part of their study activity.

vi) Since the 400 kV Chandrapur-Parli T/c is a very important corridor for power flow, the relays on this line should be replaced at the earliest by latest type of numerical relays. Meanwhile the feature of lenticular characteristics available in micromho relay may be used as an interim measure instead of circular characteristics

MSETCL has confirmed that all the three feeders of 400 kV Chandrapur – Parli are fitted with numerical Areva make Micom- P 44 2 relays at both ends as main-I and main-II protection and the recommendation has been complied.

feature being presently used.

vii) With the tripping of ± 500 kV Chandrapur-Padghe HVDC link, large quantum of power gets suddenly diverted to other alternative A.C. networks and usually results in tripping of a number of lines on power swings. The Committee recommends that with the tripping of the both poles of HVDC link, generation level at Chandrapur thermal power station of MSPGCL may be brought down automatically to prevent spread of the disturbance. WRPC may work out a suitable scheme in consultation with MSETCL

MAHAGENCO & MAHATRANSCO were requested to expedite action to formulate the scheme.

105th PCM MAHAGENCO representative informed that the matter has been taken up with MAHATRANSCO. MAHATRANSCO representative told that a study group has been formed at HO level to study the matter and come up with draft scheme, which would then be taken up for discussions in the PCM. During 106th PCM MSETCL representative informed that the Study Group has commenced the studies and they would submit their report.

viii) In the grid disturbance of 25th February, 2007, the ER-NR inter tie got tripped resulting in disconnection of NR grid from ER grid. Subsequently, some more inter-regional links between ER/NR and NR/WR have been added which may help in reducing the impact of a disturbance in a Region on other Regions operating in parallel. However, the committee is of the view that special protection scheme be worked out on priority and implemented between the various Regions operating in interconnected mode so as to minimize the impact of a disturbance in a region on other regions.

Matter regarding formulation of special protection scheme to avoid disturbance due to occurrence in other region has been referred to CEA New Delhi for further action. WRLDC informed that they are in process of carrying out studies in order to devise special protection schemes in the event of tripping of regional links. As NR, WR, ER and NER are interconnected with many 400kV and 220kV links, a composite study is required to arrive at SPS in connection with regional links. The results of the studies carried out by WRLDC will be put up to the Protection Committee for further action.

Annex. 5.08 COST OF PLCC PANEL : As per Latest LOA placed for Sipat Substation : Sr. No. Item

Description Make Unit Qty Unit

price ( Rs)

1 Terminal type ETL-41

ABB Nos. 1 375500

2 Protection Signalling Equipment type NSD -50 suitable for 4 commands

ABB Nos. 1 123600

Total 499100 Total

Amount 30 14973000

Replacement of Old PLCC( ETI, NSD60 ) for the following lines in WR-1 SR. No. Name of Sub-station Feeder Name Panel to be replaced

1 Bhadrawati 400 kV Bhilai 1 400 kV Raipur 2 400 kV Chandrapur - I 2 400 kV Chandrapur - II 2

2 Raipur 400 kV Korba - I 2 400 kV Bhilai - I 2 400 kV Bhadrawati 2

3 Bhilai 400 kV Korba - I 2 400 kV Korba - II 2 400 kV Koradi 1 400 kV Raipur - I 2 400 kV Raipur - II 2 400 kV Bhadrawaati 1

4 Koradi 400 kV Bhilai 1 400 kV Satpura 2

5 Chandrapur 400 kV B'wati - I 2 400 kV B'wati - II 2 TOTAL 30

central electricity authority piscama xao~iya ivavut ...wrpc.gov.in/pcm/106pcm_minute.pdf · please...

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