central electricity authority piscama xao~iya ivavut ... · intimated that tpc islanding system...

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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�¸¾“ˆÅ ˆÅ¸ ˆÅ¸¡¸Ä¨¸¼î¸— Sub :- Minutes of 107th Protection sub-Committee Meeting held on 19th & 20th November 2009 at

Lonawala. Ÿ¸− ½̧™¡¸ / Sir,

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Please find enclosed herewith the minutes of 107th Protection sub-Committee Meeting of Western Regional Power Committee Mumbai, held on 19th & 20th November 2009 at Lonawala 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 107th PROTECTION COMMITTEE MEETING

The 107th Protection Committee Meeting of WRPC was held on 19th and 20th November 2009 at

Lonawala. The list of participants is placed at Annex -I.

Shri S.G.Patki GM TPC welcomed all the members to the 107th PCM and expressed great privilege and

thanked WRPC for giving an opportunity to TPC to host this meeting. He further expressed that the PCM is a

knowledge sharing platform gained by experts of different utilities in the field and hoped that the WR would

always gain from the discussion and experience of utilities on integration of relays in an automated system and

review of concepts, that are changing with the changing trends in the modern protective relaying system. He

intimated that TPC islanding system presently in operation has worked well in the past during major grid

disturbances and saved Mumbai system. He said that with the envisaged 400kV interconnections to be

established with Maharashtra STU in the near future, the existing islanding scheme might require review

considering the above aspect. He further intimated that the performance indices/reliability indices in respect of

TPC system for the year 2008-09 have shown improvement over the past years.

Shri Manjit Singh, Member Secretary, WRPC, welcomed all the members and invitees to the 107th

Protection sub-Committee Meeting. He expressed thanks to TPC for hosting the meeting at this venue and for

making excellent arrangements made by them for the meeting and comfortable stay of the members here. He

stated that the WR grid strengthening is taking place with stronger inter regional interconnections, which has

resulted in more stable operation of the interconnected grid. The disturbances have got minimized due to

adherence by the WR constituents to the continually improved operation and adopting improved protection

practices in the region. The protection related matters are discussed with high technical spirit and the forum

receives useful suggestions/inputs in improving the operation of the WR grid in secured manner. It is expected

that the forum shall always continue to make efforts towards improvements in the regional protection system

by periodically reviewing the existing protection systems in the WR. He hoped that various protection related

issues included in the agenda of this meeting would be resolved during the two day meetings at Lonawala.

He then requested Shri S. Satyanarayan, Executive Engineer (P&S), WRPC to take up Agenda items

for discussion.

Item No.1: Confirmation of Minutes of 106th Protection Committee Meeting.

Executive Engineer (Protection), WRPC, stated that Minutes of 106th PCM, held on 01st and 02nd

September 2009 at WRPC Mumbai, were circulated vide WRPC letter no. Prot./106 PCM/2009/WRPC-10162

dated 18th September 2009. No comments were received from any of the members and the minutes of 106th PCM

circulated vide above referred letter were confirmed.

Item No.2: System disturbances

2.1: System disturbances in GETCO/GSECL system

(i) System disturbance at Dhuvaran CPP in GSECL system on 04-07-2009.

GSECL representative informed that on 04-07-2009 at 05.51 hrs, Bus Bar Protection of

132kV Bus-I operated with ‘C’ Phase indications on Bus Bar Panel (Alstom make PBLSB), due to

which all lines, transformers and generators connected to Bus I tripped on operation of bus bar

tripping relays 96 at Dhuvaran CPP.

On detailed checking, the arcing horn of bypass isolator contact of 132 kV Limdi Line

No.1 was found on ground with arcing spots. The arcing spots were also observed on disc insulator

and on the structure of bypass isolator.

He further informed that the isolator was commissioned in 2001 and is used under

emergency only. Preventive maintenance and thermography is being carried out regularly due to

corrosive atmosphere (coastal area). He intimated that the periodicity for carrying out thermography

would be increased as a remedial measure.

132 kV Bus I was charged at 09:40 Hrs and all the elements were restored by 10:22hrs.

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

(ii) System disturbance at Wanakbori TPS in GSECL system on 18-07-2009.

GSECL representative informed that on 18-07-2009 at 15:50 hrs., LBB protection of

Generator Transformer Unit # 2 operated and all 220 kV lines , station transformers and Units

connected to 220 kV Bus – II tripped on operation of ‘96’ relay at Wanakbori TPS.

He further informed that on detailed checking it was found that the K-177 core of the

control cable from switch yard C/R to main C/R – GRP, used for extension of DC, after operation of

master trip relay 86G1 & 86G2 (from GRP TB No. GP-3/15 to SCP TB No. 2TB-11), was found

earthed and also there was a persisting DC system +ve grounding, due to which DC +ve got extended

to 50LBB relay. The O/C is set at 50mAmps.

220 kV Bus – II charged at 16:31 Hrs. and other 220 kV Lines, Transformers and

Generators were taken in service by 18:58hrs.

Members deliberated on the issue and suggested that,

1) The element whose LBB protection has operated should be tripped

instantaneously and other elements of the bus section with the time delay so

that the effect of mal operation of LBB and or leakages in control wirings

would be minimized.

2) An additional 86 relay contact may be wired in the –ve DC extension to the

LBB relay, so as to ensure the correct operation of the LBB protection.

3) The LBB O/C element settings may be reviewed and be raised to normal load

current carried by the element.

Reservations were expressed by some of the members on the above suggestions due to

following reasons,

1) Highly resistive faults will not be detected by the LBB relay in a real stuck breaker

condition and the evolving faults may not be isolated for suggestion at 3.

2) In case of suggestion 2 there will not be a firm connection of –ve DC to the trip coil and

may result in corrosion of the connections of the trip coil. Though the additional

interlock would ensure redundancy of the correct sensing of the fault by the LBB,

however may result in further complications in the control wiring.

Committee in general felt that the suggestions needs to be looked at depth and

may be taken up while reviewing the protection manual. However the control circuit needs

to be checked during the routine testing of these relays.

2.2: System disturbance in MPPTCL/MPPGCL system

(i) System disturbance at 400 KV S/S Indore in MPPTCL system on 19-04-2009.

(The occurrence is for the quarter April 09 to June 09 (would have been covered in 106th PCM).

However the tripping of some elements due to this occurrence were reflected in Annex. 3 of the 106th

PCM and the occurrence could not be discussed for want of more details in the 106th PCM.)

MPPTCL representative informed that on 19-04-09 at 13:14 Hrs, 400 KV Indore - Nagda

feeder tripped on Main I & Main II, Z1 indication at Indore end and on Main I & Main II, Z2 at

Nagda end. Simultaneously LBB Relay of 400kV Indore-Nagda Feeder at 400kV Indore S/S

operated and tripped the 400kV Bus – Coupler and feeders connected to 400 KV Main Bus – I

All the relays of 400kV Indore-Nagda feeder were checked and the results were satisfactory.

LBB relay of this feeder was connected in two over- current and one earth fault mode. The same has

now been changed to all over current relay with Current setting 0.8x1.4=1.12 and Time setting 200

ms.

He further informed that on detailed inspection, the relays at both the ends operated

correctly. It was suspected that breaker at 400kV Indore end operated with a delay, resulting into

initiation of LBB Relay. However on checking the breaker timings, the CB was found working

correctly. The EE make timer of the LBB was picking up at a time delay of 130msec for a set time

delay of 200msec. The faulty timer was replaced.

After yard inspection all the feeders were normalized one by one by 17:23hrs.

Committee felt that the operation of LBB is undesirable. Sensing the fault at

Nagda end (400kV Indore-Nagda feeder) by the distance protection in Zone-2 indicates

that the D/T was not sent from Indore end and/or not received at Nagda end. Committee

further recommended for draining of moisture regularly for pneumatic breakers, since

this leads to corrosion of the operating mechanism resulting in delayed operation/clearing

of fault. Committee also felt that due to non availability of the SOE and DR records it is

very difficult to arrive at any conclusion and suggest remedial measures and insisted that

utilities should make available such records along with the disturbance reports.

(ii) System disturbance at 400kV Satpura S/S in MPPGCL system on 27-08-2009.

MPPGCL representative informed that on 27.08.2009 at 16:15hrs., the 400kV Bus-Bar

differential (Zone 1, Y-ph) protection operated and all the elements connected to Bus-I tripped

at 400kV Satpura S/S. Simultaneously 400/220kV ICT also tripped on instantaneous O/C (B-

ph) protection.

During yard inspection, the Y-phase conductor of 400kV Main Bus-I was found

snapped and broken about 8 inches from PG clamp connector near the Bus Transfer bay and B-

phase CT of Bus Coupler bay (Main Bus-I) was found damaged (Oil splashed from the top of

the CT).

All the feeders/Generators were immediately shifted to Bus II and were restored by

17:34hrs. The Bus-I Y-phase conductor fault was attended on 27.08.09 and the B-phase CT was

replaced on 28.08.09.

Committee observed that the operation of Bus Bar differential protection was in order.

However tripping of 400/220kV ICT on instantaneous O/C is undesirable. The need for

providing/enabling the instantaneous/High set feature of O/C, E/F (backup protection) may be

reviewed during the protection manual review.

2.3: System disturbance in NTPC system

(i) System disturbance at Korba STPS in Chhattisgarh system on 13-09-

2009.

CSPGCL representative informed that on 13.09.2009 at 14:54hrs, the Y phase ‘Drop Jumper’ of

wave trap of 400kV Bhatapara line got snapped and came in arcing zone with R-ph of Bus-3 at Korba

(NTPC) STPS resulting in a bus fault.

The 400kV Lanco, VSTPS-2 and Bhatapara lines along with U#6, connected to Bus-3 tripped at

Korba(NTPC) STPS on operation of the Bus Bar Protection Scheme. The 400kV KSTPS-Bhilai#2

tripped on Z-2 carrier received (permissive code not transmitted from Korba end) from Bhilai end and

eventually tripped on stage-1 O/V at Korba end, due to spurious signal received at Bhilai end (The PLCC

panel is of BPL make NSD-60). The 400kV Korba(W)-Bhilai lines tripped from Bhilai end. Due to this

only 3 no. of lines viz. Korba(W), Bhilai#1 and VSTPS#1 were available for evacuation with generation

of around 1400MW. The 220kV Chattisgarh system was critically loaded. Korba STPS backed down

generation by 400MW and Chattisgarh backed down generation by about 300MW. U.I. to SR was

reduced by 550MW. At 15:11hrs Korba(NTPC)-VSTPS#1 tripped on B ph-E single phase tripping.

However A/R was not initiated at Korba end and 3 ph tripping took place due to pole discrepancy Trip

(flow on this line just prior to tripping was @1189MW). At 15:12Hrs. Korba (NTPC)-VSTPS#1 tripped

on R-Y ph-ph fault at VSTPS end only and O/V at Korba STPS. At 15:31hrs Korba (NTPC)-Korba(W)

was tripped manually from Korba (NTPC) end. All the running units (U#2, U#3, U#4, U#5) at Korba

STPS tripped.

The 220kV Korba(E)-Suhela and Korba(E) -Bhilai, 220kV Korba(W)-Mopka-Bhatapara,

Korba(E)-Banari and Kotmikla-Amarkantak#1&2 got severely loaded and tripped. Generation at

Korba(E), Korba(E) extn., Korba(W), Balco got islanded and tripped along with loads of Manendragarh,

Vishrambaug and Korba(E) due to tripping of the above lines. Also due to critical loading of 220kV

system of Chattisgarh, Korba(E)-Budipadar#2&3 were hand tripped by Chattisgarh.

A generation of 3700MW and a load of 250MW in Chattisgarh system was affected. There were

no other trippings in the rest of region and the grid survived.

Start up power was extended to Korba STPS at 15:38hrs, by charging Korba STPS-VSTPS#1.

Korba STPS Unit#3 was lit up at 18:15hrs. All the affected elements were restored by 20:28hrs except

Korba(W)-Bhilai (due to PLCC problem), Korba STPS-Bhatapara and Bus-3 (due to fault), and korba

STPS-VSTPS#2 (due to isolator problem)

Committee observed that the operation of the Bus Bar protection was in order, however

due to tripping of 400kV KSTPS-Bhilai#2 from Bhilai end on receipt of spurious PLCC signal,

aggravated the situation. Committee felt that a statistical data of mal operation of PLCC schemes

of various manufacturers needs to be compiled at the RPC level and requested constituents to

submit the data of PLCC (along with make, type & date & time of operation) mal operations for

the last one year to WRPC.

Also Committee felt that the periodicity of thermovision scanning be raised and this

activity be closely monitored at important S/S’s particularly at the Generating Stations.

ITEM NO. 3: Tripping of lines / ICTs:

The incidences of tripping of lines and ICTs during the period 01-07-2009 to 30-09-2009 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:

5.1: 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.

CSPTCL representative informed that there is no provision of D/T in the existing PLCC system

and also spares are not available. However the carrier inter-trip has been provided at the above S/S’s.

Committee felt that CSPTCL may explore the possibility of making provision of D/T in the

existing panels.

5.2: 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&S) WRPC stated that the representative of Goa Electricity

Department is not present for this meeting due to certain administrative reasons at their end. The sub-

committee suggested that the presence of concerned representative from each of the constituent member

utilities in protection forum is important from the point of view of arriving at consensus decision in the

interest of improved regional system operation. Executive Engineer (P&S) WRPC would take up the

matter with Goa Electricity Department accordingly.

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

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

Executive Engineer (P&S) informed that 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.

During the 106th PCM, MPPTCL representative clarified that event loggers were available in the

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

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. However members of PCM felt that 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.

MPPTCL representative requested for a list of events that are required to be logged in a event logger. The list

of events that are required to be logged as a standard practice in PGCIL S/S’s is enclosed at

Annex.-5.3.

During the 106th PCM, 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, and for incorporating the events logging for generating units, the same shall be taken up during

unit outages. MSETCL and MSPGCL representatives agreed to co ordinate the same.

5.4: Pending SOE connections and erroneous data in SCADA.

Executive Engineer (P&S) informed that 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.

WRLDC representative said that the list had already been circulated to the respective state

LDCs. However it was felt that this data would be circulated 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.

During the 106th PCM members agreed for making MTR contacts to be input for SOE connections to

maintain uniformity and also to correct SOE connections accordingly.

The list of locations from where erroneous data is received and the locations where SOE

connections are yet to be established is enclosed at Annex.-5.4.

Committee felt that corrective actions may be expedited by the constituents.

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

settings of the modern protection relays.

Executive Engineer (P&S) informed that it was decided in the 103rd PCM that the protection manual

prepared by the then WREB (now WRPC) 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.

During the 106th PCM 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.

Shri P.Pentayya AGM WRLDC opined that the review of the protection manual may be done keeing in

view present facilities of analytical studies. There should be co-ordination between the results of the Short

Circuit/transient studies and be considered and validated through observations of information (switching swings)

during operation of reactors/ DR data etc.

Shri S.G.Patki GM TPC opined that during the review of the protection manual guidelines on R&M of

relays may be incorporated.

Committee felt that a small group should be formed for formulation of the draft report that would

then be put up in the PCM for its approval.

The members for the Protection Manual Group were nominated and are as follows,

WRPC - 1) Shri Satyanarayan S., E.E.(P&S).

2) Shri P.D.Lone, A.D.-I (P&S).

WRLDC – Shri P.Pentayya AGM.

PGCIL - 1) Shri Anand Dubey

2) One representative from WRTS-I

MSETCL – 1) Shri Shashank Jewalikar, Dy.E.E.,400kV Parli S/S.

2) Shri S.S.Rajurkar, Dy.E.E. Corporate Office Bandra.

3) Shri Amit Kulkarni, A.E. Corporate Office Bandra.

GETCO – Shri J.N.Pancholi, S.E.(T), Vadodara

MPPTCL – Shri A.K.Shrivastava, E.E.(T), Indore

CSPTCL - Shri P.M. Jog, S.E.(T)

TPC - Shri G.T.Jawale, Asst. Manager.

Reliance Infra - Shri D.M.Devasthale, Sr.Manager.

NTPC, NPCIL & Torrent Power representatives informed that they would interact through email.

Shri Satyanarayan S. Executive Engineer (P&S) WRPC informed that as per last PCM discussions an

informal email group on protection is formed. Members of PCM were requested to join the group at

http://tech.groups.yahoo.com/group/wrpc_protection_group.

5.6: 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.

CSPTCL representative informed that the Bus Bar scheme is out of service since last one year, due

to faulty Bus Bar scheme and burnt control cables at Korba (W) S/S and have initiated the process for

procurement of the same.

Committee felt that the commissioning of Bus Bar protection scheme at the above S/S may be

expedited.

5.7: Delayed trippings of 220kV Vapi-Kharadpada#1&2 and Vapi-Magarwada#1&2

lines

PGCIL vide their letter WR-II/VDR/O&M/RL/270/1580 Dtd.10th September 2009 and WR-

II/VDR/O&M/252/RL Dtd.29th October 2009 have informed that,

(i) The faults on Vapi-Karadpada#1 on 04.09.2009 at 03:15 hrs and 05.09.2009, were cleared with a delay

from Kharadpada end, though the faults were in Zone-I for both the ends and was cleared from Vapi end

instantaneously. This has resulted in tripping of Vapi-Kharadpada#2 in Zone-II from Vapi end.

(ii) Similarly for a B Ph to ground fault on Vapi-Magarwada #2 (Zone-I fault for both ends) line on 08.08.09

at 09:53hrs., Vapi-Magarwada#1 tripped in Zone-II from Vapi end, due to delayed clearence of the fault

from Magarwada end.

Executive Engineer (P&S) informed that since representative from Electricity Department

Daman is not present for this meeting, the issue would be taken up with Electricity Department Daman

separately.

5.8: Protection related problems at Indore S/S.

MPPTCL vide their letter No 742/5000/S-1 Dtd nil have informed that DC leakage was found in the

400kV Asoj-II and Itarsi-I feeder’s line and NGR reactors terminal connectors of the marshaling box causing

unwanted trippings and damages to the relay. The defective connectors of Asoj-II feeder were replaced by

MPPTCL, however The defective connectors of Itarsi-I feeder are yet to be attended. MPPTCL have requested an

early action in this regard from PGCIL.

Main-I protection (RALZB) of Itarsi feeder is defective since 17th June 09 and the feeder has healthy

Main-II protection. Also MPPTCL have requested for an early replacement of the existing non numerical relays

provided on PGCIL feeders at 400kV Indore S/S by numerical relays and the defective Main-I protection of Itarsi

feeder.

PGCIL vide their letter No. WRTS-II/VDR/O&M/RL/272/139/2539 Dtd 17/20th July 2009 have

informed that the relays are in procurement stage and would be installed in due course.

PGCIL representative informed that the terminals have been replaced and the Main-I protection

for Itarsi feeder is under procurement and would be installed shortly.

5.9: Testing of Distance Protection Schemes for lines emanating from Kawas to

GETCO.

GETCO vide their letter No. CE(TR)/ACE (Testing)/WRPC/11/56 Dtd.05.09.2009 have intimated that

the testing of the Distance Protection Schemes along with the PLCC feature for the lines emanating from Kawas

S/S to GETCO system is pending since 2006.

PGCIL representative informed that the issue could be resolved by having a meeting and testing

the Distance protecting scheme jointly with GETCO. Since the PLCC panels are imported and the spares

are not available, the same are required to be replaced.

ITEM -6 : Wide Area Measurement System (WAMS) in Western Region.

Executive Engineer (P&S) informed that in continuation to the discussions held in the 105th &

106th PCM on the WAMS project proposed by POWERGRID for Western Region, a special meeting to

discuss the technical details of the proposed WAMS project was held on 17.09.2009.

The outcome of this meeting was put up in the 11th TCC/WRPC meetings held on 24th & 25th

Sept. 2009.

The WR Power Committee approved the implementation of WAMS project in WR proposed by

POWERGRID with consortium partners TCS, IIT Bombay & TATA POWER Company Ltd., and

recommended that repayment of loan from CSIR may be made through UI cap fund, for which WRLDC shall

approach CERC for necessary approval and suggested that in case of non-approval from CERC, the matter

shall be placed before WRP Committee for further direction. The WR Power Committee also approved

formation of the Task force and PMU group to facilitate implementation of WAMS project in the region.

The Protection sub-Committee noted as above. Accordingly the Protection sub-Committee

suggested to constitute Task force and PMU group as follows :-

1) Task force shall comprise CE (LD)’s of all the State Utilities including members from WRPC,

WRLDC PGCIL and TPC. However CE(LD)’s of each State Utility may nominate additional

member for Task force, if required.

2) The PMU Group shall comprise one member each from the field of Protection, SCADA, and

System Studies. Provision for suitable alternate members for PMU group may also be kept. The

concerned CE(LD) of the Task Force of the utility may nominate members for PMU group from

Generation and Transmission utilities from that State.

All constituents were requested to send the nominations for the above Task force members/ PMU

group members.

ITEM NO.7: Other Issues

7.1 : Dynamic Power System Stability Monitoring System :

Executive Engineer (P&S) informed that during the 105th PCM held on 18th June 09 at WRPC Mumbai,

M/s A-Eberle System gave a presentation on Dynamic Power System Stability Monitoring System (DPSSMS)

comprising of Collapse Prediction Relay (CPR), which interprets system states on the basis of several

independent processes of non-linear signal analysis and determines indicators relevant for the state of the system

and dynamics of grid. The documentation was enclosed as Annex-8A of the minutes of the 105th PCM circulated

vide WRPC letter No. Prot./105 PCM/2009/WRPC-6994 Dtd. 06th July 2009. WRLDC vide their letter

WRLDC/OS/1501/09 Dtd. 11th November 2009 had requested for response/comments from the constituents on

the above system.

The letter received from WRLDC was circulated to the members of the Protection sub-Committee vide fax

dtd.16.11.09.

Committee felt that more understanding of the DPSSMS is required and since CPR has already

been installed in the REL system by M/s A-eberle, out come of the experience may be shared amongst the

members so as to enable them to give their view on DPSSMS.

7.2 :System disturbances at 400 kV VSTPS Vindhyachal S/S in NTPC system on 03.10.2009 and

04.10.2009.

Member Secretary WRPC informed that there were two major disturbances at NTPC Vindhyachal STPS

on 03.10.09 and 04.10.09. Though the period of these occurrences falls in the purview of the next PCM, any

disturbance leading to loss of generation at this generating station endangers the stability of the WR grid and

hence needs to be discussed in this forum due to severity of the trippings.

NTPC representative informed that on 03.10.09 at 03:26hrs, the 400kV Bus-2 tripped on operation of

the Bus Bar protection of Bus Coupler 1 (between Bus-1 & Bus-2) due to shorting of the corona ring and IPS

tubes of 400 kV side HVDC-2 R and Y phase because of intense water vapour from cooling towers (because of

high humidity). All the elements connected to Bus-2 along with the Bus Sectionalizer-2 tripped. Simultaneously

Unit#7 (connected to Bus-4) and Unit 8 (connected to Bus-3) tripped on Generator Differential Protection -87G1

On investigation it was found that the tripping was due to mal-operation of ABB-RADHA (High impedance

scheme) make relay for a through fault. The operation of relay for such transient fault is being investigated by

internal committee (NTPC).

NTPC representative further stated that on 04.10.09 at 12:04hrs, after the bus bar protection operation on

03/10/2009, Bus-2 was charged through bus coupler-1 & Bus Section -2 and was kept floating overnight. On

04/10/2009 VJ-4 was under the process of transfer from Bus-1 to Bus-2. As soon as open command was given to

the Bus-1 isolator of VJ-4, Bus-1&2 tripped. On investigation it was observed that the LBB trip protection relay

K96 of Bus Coupler-1 operated on 03/10/2009 was not resetted /got stuck. While transferring VJ-4 from Bus-1

to Bus-2 on 04/10/09, the load current of VJ-4 feeder through Bus Coupler caused the operation of LBB relay.

Committee felt that the operation of protection scheme on 03.10.09 was in order. However necessary

steps are required to be taken to avoid accumulation of water vapors on the S/S yard equipments from the near by

cooling towers so that such incidences could be avoided in future. Also the recommendations of the report of the

“Study Group on the disturbance of 22.07.08 at Vindhyachal STPS”, circulated vide letter No.

WRPC/Prot./Vindya/2008-09/5891 Dtd.03.06.09 be followed and the compliance of the same may be submitted at

the earliest. NTPC representative intimated that recommendations at paras (ii),(iii),(iv) &(v) of the report of the

“Study Group on the disturbance of 22.07.08 at Vindhyachal STPS”, have been implemented and the

recommendation at (vi) would be complied soon. Committee suggested that the recommendations of the above

report may be fully implemented by all the concerned generating utilities and compliance of the same or other

wise may be intimated in the next PCM. Regarding the recommendation at para (i), namely to bring out best

practices of S/S equipment maintenance can be formulated after organizing a workshop on best practices of S/S

equipment maintenance. It was suggested that the workshop might be arranged in May/June 2010.

Committee further felt that the occurrence of 04.10.09 due to operation of LBB protection seems to

be logically in correct, since taking the feeders into service connected to the Bus section without resetting

the LBB relay (which was operated on 03.10.09), is impossible. Hence the matter may be further

investigated along with additional observations/data pertaining to the incidence by NTPC and discussed in

the next PCM.

ITEM NO. 8: Date and Venue of the next meeting.

It was decided that the next Protection sub-Committee meeting (108th) will be hosted by MAHAGENCO

(MSPGCL), in February 2010, wherein system disturbances for the period 01/10/2009 to 31/12/2009 will be

discussed. Exact date and venue will be communicated separately.

ANNEX-I LIST OF PARTICIPANTS

107th Protection Committee Meeting held on 19th & 20th November 2009 at Lonawala.

GSECL (Gujarat State Electricity Corporation Limited)

Shri U.D. Adharyu Add. Chief Engineer (GT) Vadodara

GETCO (Gujarat Energy Transmission Corporation Limited)

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

MAHAGENCO (Maharashtra State Power Generation Company Limited)

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

MSETCL (Maharashtra State Electricity Transmission Company Limited)

Shri S.G.Kelkar Chief Engineer (Load Dispatch) Shri B.L.Pasarate Executive Engineer (T), Washi 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 P.A.R. Bhende Superintending Engineer (SLDC) Jabalpur Shri A.K.Shrivastava Executive Engineer (TCC), Indore

MPPGCL (Madhya Pradesh Power Generation Corporation Limited)

Shri P.C.Soni Executive Engineer (Thermal Design), Jabalpur

CSPTCL (Chattisgarh State Power Transmission Corporation Limited)

Shri P.M.Jog Superintending Engineer (T&C), Bhilai

CSPGCL (Chattisgarh State Power Generation Corporation Limited)

Shri M.K.Sharma Executive Engineer (T), Korba(W) Shri G.P.Rai Executive Engineer (T), Korba(W)

NPCIL (Nuclear Power Corporation of India Limited)

Shri V.M. Daptardar SME (E) TAPS-1&2, Tarapur Shri A.N. Thakur SME (E) TAPS-3&4, Tarapur

NTPC

Shri Jitendra Tewari D.G.M. (EMD) Vindhyachal STPS Shri N.P.Dewangan Dy.Supdt. NTPC Korba Shri A. Jaya prakash Sr.Engineer NTPC Sipat

PGCIL (Power Grid Corporation of India Limited)

Shri Anand Dubey Manager WRTS-II, Vadodara

REL (Reliance Infra Ltd.)

Shri M. R. Waingankar Manager (Trans), Mumbai.

TPC (Tata Power Company)

Shri S.G.Patki G.M.(Engg) Shri J.D.Shrotri Deputy G.M.(Engg) Shri S.C.Tiwari A.G.M.(ETA) Shri A.Mukharji Chief Manager(ETA) Shri T. Murali Krishna Chief Manager, Trombay, Mumbai Shri M.V. Kini Assistant General Manager Shri G.T.Jawale Assistant Manager, Trombay

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 S.G.Tenpe Superintending Engineer © Shri Satyanarayan S. Executive Engineer (P&S) 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

3.01 400 KV Wardha

400 KV Wardha - Akola # 2

PGCIL (Y) 01.07.09 09:12 02.07.09 00:00

Line tripped on Y-Earth fault, Y phase conductor snapped at 118.1km from Wardha.A/R attempted.

3.02 400 KV Raigarh

400 KV Raigarh - Rourkela # 2

PGCIL (Y) 01.07.09 13:58 01.07.09 13:58

Line successfully Auto reclosed at both ends on R phase to Earth fault at 51.37km from Raigarh end.

3.03 400kV Khandwa

400kV Khandwa-Rajgarh#2

PGCIL (Y) 01.07.09 1:49 01.07.09 2:24

A/T at Khanwa end only due to PLCC Mal-operation at Rajgarh end. BPL Panel

3.04 400kV Khandwa

400kV Khandwa-Seoni#1

PGCIL (Y) 01.07.09 11:39 01.07.09 11:39 A/R on transient R-N fault

3.05 400 KV Korba

400 KV Korba - Vindhyachal # 1

PGCIL (Y) 02.07.09 15:42 02.07.09 19:37 Line A/T on Reactor Protection

(Buchholz Trip) at Korba end.

3.06 400kV Khandwa


PGCIL (Y) 02.07.09 11:24 02.07.09 11:42

A/T at Khanwa end only due to PLCC Mal-operation at Rajgarh end. BPL Panel

3.07 400 KV Seoni

400 KV Seoni- Bhilai (LILO portion)

PGCIL (Y) 03.07.09 10:19 03.07.09 11:12

Line tripped due to receive of Direct trip signal from Bhilai (CSEB) S/S.

3.08 400KV Bhadrawati

400KV Bhadrawati-Chandrapur # 4

PGCIL (Y) 03.07.09 19:39 03.07.09 19:39

Line successfully A/R at both ends on R-E fault.F/L=7.61 KM from Bhadrawati end.

3.09 400kV Jabalpur

400kV Jabalpur-Itarsi#4

PGCIL (Y) 03.07.09 4:33 03.07.09 4:52 A/T on Ph-Ph(Y-B) fault

3.10 400kV Jabalpur


PGCIL (Y) 04.07.09 6:11 04.07.09 6:30 A/T on Ph-Ph(Y-B) fault

3.11 400kV Indore

400kV Indore-Asoj#1

PGCIL (Y) 04.07.09 20:41 04.07.09 21:02 A/T on Y-N transient fault.

3.12 400 KV Raipur

400 KV Raipur - Sipat # 1

PGCIL (Y) 05.07.09 16:16 05.07.09 16:16

Line autoreclosed successfully at both ends on Y-E fault 48.6km from Raipur end.

3.13 400kV Indore

400kV Indore-Asoj#1

PGCIL (Y) 08.07.09 1:20 08.07.09 13:20

A/T on transient (R-N) fault also REF protection of Line Reactor optd. for a nearby fault. Setting revised.

3.14 400kV Bina 400kV Bina-Nagda#1

PGCIL (Y) 08.07.09 15:01 08.07.09 15:01 A/R on transient B-N fault.

3.15 400kV Jabalpur


PGCIL (Y) 08.07.09 20:21 08.07.09 20:31 A/T on Ph-Ph (Y-B) fault.

3.16 400kV C'pur 400kV C'pur-Parli#2

MSETCL (Y) 09.07.09 16:48 10.07.09 14:49

Transient R-N fault. A/R was in non-auto mode due to breaker problem at Giravali end. The same is taken in service on 10.07.09 14:49hrs.

3.17 765 KV Seoni

765 KV Seoni-Wardha # 1

PGCIL (Y) 09.07.09 06:02 09.07.09 24:00 Line tripped on over voltage.

3.18 400 KV Seoni


PGCIL (Y) 09.07.09 11:34 09.07.09 12:03

Line tripped due to receive of Direct trip signal from Bhilai (CSEB) S/S. BPL Panel

3.19 400 kV Soja 400 kV Soja-Kansari

GETCO (Y) 09.07.09 23:32 09.07.09 22:32

Auto Reclose operation succefully. Transient tripping.After patroling no cause found.

3.20 400 KV Raipur

400 KV Raipur - Raigarh # 1

PGCIL (Y) 10.07.09 23:46 11.07.09 00:42 Line tripped on Over Voltage

protection.

3.21 400 KV Seoni


PGCIL (Y) 11.07.09 12:21 11.07.09 12:48

Line tripped due to receive of Direct trip signal from Bhilai (CSEB) S/S. BPL Panel

3.22 400 KV Seoni


PGCIL (Y) 11.07.09 13:33 11.07.09 14:21

Line tripped due to receive of Direct trip from Bhilai (CSEB) S/S.

3.23 400 KV Raipur

400 KV Raipur - Sipat # 1

PGCIL (Y) 11.07.09 14:13 11.07.09 14:13

Line A/R successfully at both ends on B-E fault . F/L=109.7 Km from Raipur end.

3.24 400 kV Soja 400 kV Soja-Wanakbori

GETCO (Y) 11.07.09 0:41 11.07.09 1:41

(1) At Wanakbori end Auto reclose operated (2) At soja end breaker tripped due to it was on TBC . After patroling no cause found.

3.25 400kV Jabalpur


PGCIL (Y) 12.07.09 22:24 12.07.09 22:33 A/T on pPh-Ph (Y-B) fault.

3.26 400kV V'chal

400kV V'chal-Satna#1


3.27 400kV Khandwa


PGCIL (Y) 17.07.09 23:21 17.07.09 23:41 A/T due to OV Operated at

Rajgarh S/S.

3.28 400 kV Kansari

400 kV Kansari-Kankroli 1

GETCO (Y) 17.07.09 1:36 17.07.09 2:40

Mal operation of NGR PRD at Kankroli due to moisure inrush in PRD.

3.29 400 KV Tarapur

400 KV Tarapur - Padghe # 2

PGCIL (Y) 18.07.09 05:11 18.07.09 10:21 Line tripped on over voltage .

3.30 400 KV Boisar

400 KV Boisar - Padghe

PGCIL (Y) 18.07.09 06:49 18.07.09 09:33

Line tripped due to receive of Direct trip signal from Padghe end.

3.31 220 KV Korba(East)

220 KV Korba(East)-Budhipadar -III

PGCIL (Y) 20.07.09 18:20 20.07.09 18:48 Line tripped due to B-E fault.

F/L=129 Km from Korba(E).

3.32 400 KV Raipur

400 KV Raipur - Bhilai# 2

PGCIL (Y) 21.07.09 02:06 21.07.09 20:25

Line tripped on over voltage.CVT problem (CGL make) replaced the same.

3.33 400 KV Raipur

400 KV Raipur - Bhilai# 2

PGCIL (Y) 21.07.09 22:36 21.07.09 23:04

Line tripped on Over Voltage Protection Stage - 1 at Raipur end.CVT problem (CGL make) replaced the same.

3.34 400 kV Kasor

400 kV Kasor -SSP

GETCO (Y) 21.07.09 12:30 21.07.09 12:55 Due to over voltage 441 KV at

SSP end.

3.35 400kV C'pur 400kV C'pur-Koradi

MSETCL (Y) 23.07.09 1:26 23.07.09 9:22

O/V Stage-I tripping at C'pur (110%-5sec.) & on receipt of DT at Koradi end. Line charging delayed due to O/V condition in system

3.36 400kV C'pur 400kV C'pur-Koradi

MSETCL (Y) 23.07.09 13:00 23.07.09 15:29

O/V Stage-I tripping at C'pur (110%-5sec.) & on receipt of DT at Koradi end. Line charging delayed due to O/V condition in system

3.37 400kV Koradi

400kV Koradi-Akola

MSETCL (Y) 24.07.09 1:31 24.07.09 6:21

O/V Stage-I tripping at Akola end (110%-5sec.) & on receipt of DT at Koradi end. Line recharged at 05:50hrs but tripped on O/V.

3.38 400 kV Kansari


GETCO (Y) 24.07.09 17:57 24.07.09 18:47

Mal operation of bay control unit of main bay at Kankroli end.

3.39 400 kV Kasor

400 kV Kasor -SSP

GETCO (Y) 25.07.09 22:45 25.07.09 22:53

Auto Reclose operation succeful at SSP end. Transient tripping.After patroling no cause found.

3.40 400 KV Kolhapur

400 KV Kolhapur - Mapusa # 2

PGCIL (Y) 26.07.09 20:05 26.07.09 22:13

Line tripped on Y- Earth fault at 4.27 km from Mapusa; A/R unsuccessful due to drift in Dead-timer and found operating at 2.5 Sec. Faulty timer replaced.

3.41 400 KV Raigarh

400 KV Raigarh - Rourkela # 1

PGCIL (Y) 27.07.09 18:31 27.07.09 18:31

Line A/R successfully at both ends on R -Earth fault. F/L=202 km from Raigarh

3.42 400 KV Raipur

400 KV Raipur - Bhatapara

PGCIL (Y) 28.07.09 23:29 29.07.09 11:27 Line tripped on over

voltage.CVT problem at Raipur

3.43 400 kV Kansari


GETCO (Y) 05.08.09 8:05 05.08.09 9:55 B-Ph E ,fault in Northern

Region..

3.44 400kV Indore

400kV Indore-Asoj#1

PGCIL (Y) 06.08.09 15:24 06.08.09 15:55 A/T on transient B-N fault.

3.45 400 KV Raigarh

400 KV Raigarh-Rourkela #1

PGCIL (Y) 08.08.09 15:32 08.08.09 15:32

Line A/R successfully at both ends on B-E fault at 222 Km from Raigarh end and 20.92 Km from Rourkela end.

3.46 400 KV Raigarh

400 KV Raigarh-Rourkela #1

PGCIL (Y) 08.08.09 15:34 08.08.09 15:34

Line auto reclosed successfully at both ends on Y-E fault at 238KM from Raigarh end and 25.03 KM from Rourkela end.

3.47 400kV Vapi 400kV Vapi-Sugen


3.48 400 KV Korba

400 KV Korba - Vindyachal # 1

PGCIL (Y) 11.08.09 08:36 11.08.09 08:36

Line A/R successfully at both ends on Y - Earth fault at 29% from Vindhyachal end.

3.49 400kV C'pur 400kV C'pur-PGCIL#4

PGCIL (Y) 12.08.09 20:19 12.08.09 22:46

O/V stage-I operated at C'pur end. Problem of B ph CVT showing higher voltage by @4-5kV. Faulty B-ph CVT replaced by PGCIL on 13.08.09 by PGCIL.

3.50 400 KV Bhadrawati

400 KV Bhadrawati-Chandrapur # 4

PGCIL (Y) 12.08.09 07:10 12.08.09 08:35

Line tripped on Over Voltage protection operated at Chandrapur end.CVT problem (CGL make), replaced the same.

3.51 400 KV Bhadrawati

400 KV Bhadrawati-Chandrapur # 4

PGCIL (Y) 12.08.09 20:20 12.08.09 22:46

Line tripped on Over Voltage protection operated at Chandrapur end.CVT problem

3.52 400kV Indore

400kV Indore-Asoj#2


3.53 400kV Indore

400kV Indore-Asoj#1

PGCIL (Y) 17.08.09 15:06 17.08.09 15:45 A/T on transient R-N fault.

3.54 400kV C'pur 400kV C'pur-Parli#2

MSETCL (Y) 19.08.09 16:42 20.08.09 12:45 B ph insulator string decapped

at Loc.No.311.

3.55 400kV Koradi

400kV Koradi-Sarni

PGCIL (Y) 19.08.09 12:59 19.08.09 12:59 Transient R-N fault. A/R

successful at both ends.

3.56 400KV Bhilai

400KV Bhilai-Bhadrawati

PGCIL (Y) 19.08.09 17:58 19.08.09 17:58

Line A/R successfully at both ends on R - Earth fault at 70.17 Km from Bhadrawati end.

3.57 400 kV Chorania

400 kV Chorania-Amreli line

GETCO (Y) 19.08.09 5:34 19.08.09 18:04

fault found on Loc No 97(S) R- Ph string flash over under Amreli Juridiction and same was replaced by new one.

3.58 220kV Vapi 220kV Vapi-Kharadpada#2


3.59 220kV TAPS

220kV TAPS-Bhilad NPCIL 24.08.09 10:46 24.08.09 17:04

Tripped from both ends in Z-I. r Ph insulator flashover at Loc No.856.

3.60 220kV KAPS

220kV KAPS-Vapi

PGCIL (Y) 26.08.09 14:31 26.08.09 15:07 Tripped in Z-I R-N transient

fault.

3.61 400 KV Seoni

400 KV Seoni-Wardha # 1

PGCIL (Y) 27.08.09 11:55 27.08.09 13:20 Line tripped on over voltage.

(765kV Line charged at 400kV)

3.62 765 KV Sipat

765 KV Sipat - Seoni # 2

PGCIL (Y) 28.08.09 08:51 28.08.09 10:54 Line tripped on over voltage

3.63 400 kV Kasor

400 kV Kasor -GPEC

GETCO (Y) 28.08.09 5:15 28.08.09 17:32 Loc. 153 Y-ph st. flash over.

3.64 400 kV Kasor

400 kV Kasor -GPEC

GETCO (Y) 29.08.09 5:45 29.08.09 5:45 Transient tripping, After

patroling no cause found.

3.65 400 kV Kasor

400 kV Kasor -GPEC

GETCO (Y) 29.08.09 6:45 29.08.09 19:25 Loc. No. 195 Y-ph & 196 R-ph

st. flash over

3.66

400KV SGTPS, Substation, Birsinghpur

BRS-DAMOH Feeder

MPPGCL (Y) 01.09.09 22:50 02.09.09 13:10

BRS end – Main-II, Y Phase IA=556.5A, IB=2.1171kA IC= 325.2A, VBN=160KV. Y-phase insulator failure.

3.67 400 KV Bhilai

400 KV Bhilai - Seoni (Lilo portion)

PGCIL (Y) 01.09.09 16:07 01.09.09 16:27

Line tripped due to PLCC maloperation at Bhilai end. BPL Panel

3.68 220kV TAPS

220kV TAPS-Vapi NPCIL 03.09.09 8:55 03.09.09 17:49

Tripped in Z-I from both ends. B ph suspension insulator at Loc No.903 flashover.

3.69 765 KV Sipat

765 KV Sipat - Seoni # 1

PGCIL (Y) 03.09.09 15:47 03.09.09 21:05

Line tripped on B-Phase to Earth fault at 129 KM from Seoni end.

3.70 400kV V'chal


PGCIL (Y) 03.09.09 20:43

03.09.09 20:43 A/R successful from Satna end but A/T from Vindhyachal end.A/R problem rectified.

3.71 220kV TAPS

220kV TAPS-Vapi NPCIL 04.09.09 5:49 04.09.09 17:18

Tripped from both ends in Z-I. C Ph conductor detached from suspension insulator at Loc.No.931.





3.74 220kV Vapi 220kV Vapi-Magarwada#2

PGCIL (Y) 08.09.09 9:53

08.09.09 10:10 A/T on transient B-N fault.

3.75 220kV Vapi 220kV Vapi-Magarwada#1

PGCIL (Y) 08.09.09 9:53

08.09.09 10:08 A/T on B-N fault.due to delayed clearing of fault from Magarwada end.

3.76 400kV Satpura

400/220kV ICT

MPPGCL (Y) 09.09.09 13:45 09.09.09 14:55

220kV side Backup O/C Y-phase Optd. 220kV side Y ph LA of GT#3 failed.

3.77 400kV V'chal

400kV V'chal-Jabalpur#4

PGCIL (Y) 12.09.09 13:42 13.09.09 19:00 A/T due to DT receipt from

VSTPP end.

3.78 220kV TAPS

220kV TAPS-Vapi NPCIL 17.09.09 9:40 17.09.09 14:17 Tripped in Z-I from both ends.

No fault found.

3.79 220kV KAPS

220kV KAPS-Vapi #2

NPCIL 19.09.09 12:42 19.09.09 13:03 Tripped in Z-I from both ends. No fault found.

3.80 220kV KAPS

220kV KAPS-Vapi #2

NPCIL 19.09.09 13:33 19.09.09 14:47 Tripped in Z-I from both ends. No fault found.

3.81 220kV Vapi 315MVA ICT#2 PGCIL 19.09.09 14:27 20.09.09 6:46

A/T due to mal-operation of Buchhloz relay during sudden overloading because of system disturbance. (CGL T/F). Buccolz relay replaced.

3.82 220kV Vapi 315MVA ICT#1 PGCIL 19.09.09 14:44 16.10.09 19:00

A/T due to mal-operation of Buchhloz relay during sudden overloading because of system disturbance. (CGL T/F). Buccolz relay replaced.

3.83 400 KV Ranchi

400 KV Ranchi - Sipat # 2

PGCIL (Y) 21.09.09 21:57 21.09.09 22:56

Line tripped on B - E fault at 191.8 Km from Ranchi; A/R successful and then tripped on DT Receipt.

3.84 220kV TAPS

220kV TAPS-Borivali NPCIL 22.09.09 18:10 22.09.09 23:50 R ph insulator flashover at

Loc.No.856.

3.85 400kV V'chal



3.86 400kV Khandwa

400kV Khandwa-Seoni#1

PGCIL (Y) 29.09.09 14:00 29.09.09 14:33 A/T on R-N transient fault.

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.

1) MSETCL intimated that on 400 kV Padghe – Nagothane ckt-I, Siemens make relay as Main-I and REL 521 relay as Main-II provided at Padghe end on 13th Sept 08.- Implemented. 2) The possibility of

swapping relays was taken up and wherever possible swapping has been done so as to have different type of Main-I & Main-II relays.

3) In future in all new procurements the recommendation will be ensured by constituents- with this the recommendation is implemented.

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)

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.

B) 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 and 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.

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.

Implemented.

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

Protection Committee stressed the importance of compatible data download facility and requested constituents to arrange for same expediously.

Implemented

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.

Since PGCIL & MSETCL lines have multi-feed problem, a group from PGCIL, WRLDC & WRPC will study the problem & suggest solution in the next PCM.

vi) Since the 400 kV Chandrapur-Parli T/c is a very important

MSETCL has confirmed that all the three feeders of 400 kV

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 feature being presently used.

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.

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.

WRPC & MSETCL would carry analytical studies & report the out come in the next PCM.

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.

At present SPS for ER-SR exists. SPS for Chandrapur-Padghe HVDC is under formulation.

central electricity authority piscama xao~iya ivavut ... · intimated that tpc islanding system...

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