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

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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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Vindhyachal Super Thermal Power Station, Vindhyanagar. Ÿ¸−¸½™¡¸ / Sir,

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Please find enclosed herewith the minutes of 104th Protection Committee Meeting of Western Regional Power Committee, Mumbai held on 26th & 27th March 2009 at NTPC Vindhyachal Super Thermal Power Station, Vindhyanagar for your information and necessary action.

¤¸¾“ˆÅ ˆÅ¸ ˆÅ¸¡¸Ä¨¸¼î¸ œ¸®¸½¢¨¸ ¬¸¢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,

(‡ma.Aar.isMah /M.R. Singh)

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

http://www.wrpc.nic.in/

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MINUTES OF THE 104th PROTECTION COMMITTEE MEETING

The 104th Protection Committee Meeting of WRPC was held on 26th &

27th March 2009 at NTPC Vindhyachal STPS. The list of participants is placed at

Annex -I.

Shri S.C.Pandey, ED(V), NTPC Vindhyachal welcomed the members &

participants to the 104th Protection Committee Meeting. He stated that, through

continuous efforts and best maintenance practices NTPC Vindhyachal is

minimizing the break downs in their plant at Vindhyachal STPS. He hoped that

this forum would bring out solutions and remedial measures for the issues to be

discussed during the 104th Protection Committee Meeting.

Shri P.Patel, Member Secretary, WRPC, welcomed all the members and

invitees on behalf of WRPC to the 104th Protection Committee Meeting. He

thanked NTPC, for having willingly consented to host this meeting at NTPC

Vindhyachal, and also for making excellent arrangements and comfortable stay of

the participants of the meeting. He stated that this forum is an open group forum

and all suggestions and good inputs are always welcomed and appreciated. A

continuous effort is required to arrive at improvement in the protection system.

He hoped that various protections related issues would be resolved during this two

days meet at NTPC Vindhyachal.

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

WRPC to take up Agenda items for discussion.

Item No.1: Confirmation of Minutes of 103rd Protection Committee Meeting.

Executive Engineer (Protection), WRPC, stated that Minutes of 103rd PCM held on

12th & 13th Dec.2008 at Kanha (M.P.), were circulated vide WRPC letter no. Prot./103-

PCM/2008/WRPC/130451 dated 26th December 2008. Comments received from GSECL

vide their letter no. CEG/TESTING/318/308 Dtd.17.01.2009, regarding Item No.2.03 of

Minutes of 104th WRPC PCM

the minutes was discussed. The committee agreed to modify 5th and 6th Para of Item

No.2.03 as under,

“Committee recommended for replacement of existing porcelain type suspension

and tension insulators with silicon rubber insulators, regular hot washing and

improvement in the steady state system voltage profile in the region, since this would

minimize such occurrences.

GSECL representative informed that to control the over voltages 25 MVAR bus

reactors have been installed and are in service at 220kV Anjar, 220kV Khakhar and

220kV Nakhatrana S/S’s and installation & commissioning of 25 MVAR bus reactor

is in progress at KLTPS.”

With these modifications the Minutes of 103rd PCM were confirmed.

Item No.2: System disturbances

2.01: System disturbance at 220 kV Talangpore S/S in GETCO system on 16-10-

2008

GETCO representative informed that on 16.10.08 at 11:15hrs, blasting noise was

heard at 220kV Talangpore S/S and all the 220kV lines tripped from remote end on DPS

zone-2 resulting in zero power at the S/S. During yard inspection the 220kV Bus-A, B-ph

PT isolator’s insulator towards PT side was found damaged. Also metallic yarn of

conducting nature was found on 220kV gantry of the PT isolator. All the transformers were

hand tripped. The ABB make RADSS Bus Bar protection scheme did not operate at the

S/S.

All the 220kV lines and transformers were restored by 04:00hrs of 17.10.08.

GETCO representative further told that the slope setting of Bus Bar scheme is 0.8Amps.

The scheme was tested for A.C. and D.C. logic after the occurrence and the results were

found satisfactory. The auxiliary CT’s were tested for knee point voltage and the results

were found satisfactory.

The details of occurrence is enclosed at Annex-2.01

Committee opined that the faults due to metallic yarn of conducting nature

are generally of highly resistive nature. The non operation of the ABB make RADSS


Bus Bar protection scheme under such circumstances has been a matter of concern.

Hence past data regarding non operation of ABB make RADSS Bus Bar protection

scheme may be collected and the matter may be taken up. CT Saturation due to high

DC current component flowing during the fault initiation results in non operation of

bus bar and is another area of concern.

Committee also felt that with increasing fault levels at S/S’s, the slope settings

of Bus Bar schemes may be reviewed by the constituents in consultation with ABB.

2.02: System disturbance at 400 kV Asoj S/S in GETCO system on 28-10-2008

GETCO representative informed that on 28.10.08 at 17:14hrs, the 220/132kV

150MVA Transformer-1 tripped from 132kV side on B-ph Over Current (O/C) protection,

220/132kV 150MVA Transformer-2 tripped from 220kV side on B-ph Earth Fault (E/F)

and all the 132kV feeders tripped from remote end on B-ph Zone-2 DPS and Directional

E/F, except the radially connected feeders 132kV Manjusar-1 & 2 and Railway-1 & 2

which were hand tripped at 400kV Asoj S/S.

During yard inspection monkey was found electrocuted on 132kV side B-ph

isolator of 220/132kV 150MVA Transformer-2.

All the 132kV lines and Transformers were restored by 18:36hrs.


Committee observed that the tripping of Transformer’s and 132kV lines is in order.

2.03: System disturbance at 400 kV Khedamara S/S in CSEB system on 11-11-2008

Executive Engineer (Protection) WRPC informed that CSEB representative is not

present for this meeting, and as per the report received, on 11.11.08 at 04:58hrs, the DPS

Main-I & Main-II of 400kV Koradi feeder operated at 400kV Khedamara S/S and tripped

on Main-II DPS from remote end, due to fault on line. Simultaneous to the tripping, the R

pole of the Bus-II main breaker of 400kV Koradi line developed hunting problem at

400kV Khedamara S/S. All the feeders connected to Bus-II tripped on LBB/Bus bar

protection. The 400kV Seoni feeder connected to Bus-II, tripped at Seoni end only. The

400kV Koradi feeder was declared faulty, due to snapping of conductor.


The Bus-II was charged at 11:25hrs after replacement of moving and fixed contacts of B

phase pentagraph of 400kV Korba West Bank Bus-II, and all equipments were taken into

service by 14:28hrs of 11.11.08, except 400kV Seoni Bus-II breaker kept out for attending

heavy air leakage and 400kV Koradi Bus-II breaker for attending hunting problem in R

pole.

PGCIL, WRTS-I representative told that soil was rocky at the fault location. He

further informed that the ABB make ABCB hunted for around 10 times during the above

fault clearance and the Circuit Breaker was replaced.

Executive Engineer (Protection) informed that on 14.10.2000 there was a similar incidence

of pneumatic hunting of ABCB breaker at the same station, which is given in detail in the

report of the enquiry Committee headed by Shri A.Velayutham, MS, WREB. Further the

problem of pneumatic hunting of ABCB were also taken during an earlier PCM with ABB

representatives. These breakers are being replaced by modern SF6 breakers.


Committee observed that the operation of LBB protection is in order. The trip

circuit of 400kV Seoni feeder CB at Khedamara S/S should be thoroughly checked

since the Circuit Breaker did not trip on operation of LBB protection.

2.04: System disturbance at 220 kV Acchalia S/S in GETCO system on 27-11-2008

GETCO representative informed that on 27.11.08 at 05:50hrs, the DP relay of

220kV Ukai Hydro-2 line operated in zone-I, however the associated breaker did not trip.

“Breaker low air pressure” alarm appeared on the Facia, however there was no “trip circuit

faulty” indication. Its LBB operated thereby tripping all the 220kV breakers connected to

Bus-B and the Bus Coupler on operation of 96 Relay. The R-ph insulator string of 220kV

Acchaila- Ukai Hydro-2 line was found flash over at Location No. 285(S). The circuit

breaker on 220kV Acchaila- Ukai Hydro-2 line is of ABB make ABCB.

All the 220kV lines and transformers were restored by 10:35hrs, except 220kV

Ukai Hydro line which was restored at 18:55hrs on 29.11.08.


He further told that the DP relay provided on the line is ABB make REL 511 and

the LBB protection scheme is of Essen Reyrolle make ARGUS 2. Both the trip coils and

resistors of 220kV Acchaila- Ukai Hydro-2 line were found burnt. The CB was completely

overhauled and all the tripping and closing coils were replaced. The CB timings were

measured after the overhaul and the results were satisfactory.


Committee observed that the operation of LBB protection is in order.

2.05: System disturbance at Ukai TPS in GSECL system on 27-11-2008

GSECL representative informed that on 27.11.08 at 19:18hrs, Local Breaker Back

up (LBB) protection of GT-5 operated due to fault in AVR thyristor block 1.2.3.4,

resulting in tripping of all the lines, transformers and generators connected to Bus B on

Bus Bar tripping relay 96 at Ukai TPS. The LBB protection operated due to delayed

opening of Y pole of the breaker of GT-5 upon receiving class A trip due to short circuit in

the excitation panel of GT-5.

He further told that the circuit breaker operating mechanism was cleaned and

lubricated. The circuit breaker timings were checked and the results were satisfactory.

The 220 kV Bus B was charged at 19:25 Hrs. & 220 kV Lines, Transformers and

Generators were taken in service by 20:42hrs of 27.11.08, except 220/400kV ICT which

was taken into service at 18:46 hrs on 28.11.08 and Generator 5 which was taken into

service at 20:09 hrs on 29.11.08


Committee observed that the operation of LBB protection is in order.

2.06: System disturbance at 220 kV Savarkundla S/S in GETCO system on 30-11-

2008

GETCO representative informed that on 30.11.08 at 02:45hrs, the 220kV lines and

transformers connected to 220kV Bus-I tripped, along with the Bus coupler on Bus bar

protection trip, due to failure of B-ph CT of 220kV Bus coupler bay at 220kV Savarkundla


S/S. Along with the Bus bar tripping, the 220kV Amreli line-1 tripped on Distance relay

zone-1, 220kV Dhokalva line tripped on ARLO and the 220kV Amreli line-2 & 220kV

Sagapara lines tripped on Distance relay zone-3, which were connected to Bus-II. The

other lines and transformer connected to Bus-II were hand tripped.

He further informed that the failed 220kV CT installed on 01.09.2008, was of

TELK make dead tank type and the year of manufacture was 1995. The Bus coupler CT’s

are installed towards Bus-1 side. The failed CT was replaced by new Areva make CT on

01.12.2008 and Bus coupler was taken into service. The Tan-Delta value measured on

15.07.2008 with Doble kit was 0.56%, capacitance was 190.2 pF and IR with 5kV megger

was 22000M ohms.

All the 220kV lines and ‘transformers were restored by 05:15hrs on 01.12.08.


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

order. Committee felt that measurement of tan-delta alone couldn’t diagnose the

condition of the CT’s, since the tan-delta measurement depends on the atmospheric

conditions (i.e. temperature, humidity etc.). However under similar atmospheric

conditions 0.1% rate of rise of tan-delta value on annualized basis and significant

difference in the capacitance value compared with the same make CT’s would be an

indication towards the deteriorating CT condition.

2.07: System disturbance at 400 kV Kalwa S/S in MSETCL system on 12-12-2008.

MSETCL representative informed that on 12.12.2008 at 10:48hrs, the B-ph IPS

tube between 400kV main Bus-I & (i.e. 29LA & 29LB) isolator of 400kV Kalwa-

Lonikand line bay fell on ground from main bus-I isolator side, creating bus fault at 400kV

Kalwa S/S. This resulted in tripping of all the equipments connected to 400kV main bus-I

at Kalwa S/S.

He further told that 400kV Padghe Lonikand line was under outage for routine

maintenance work, hence load on 400kV Kalwa-Lonikand line increased from 250A to

600A. Due to increase in load on 400kV Kalwa-Lonikand line, the isolator clamp got

melted and the B phase IPs tube of 400kV Kalwa-Lonikand bay fell down thus creating a


Bus fault at 400kV Kalwa S/S. The CAG type EE make zone-1 Bus Bar protection

operated. Thermography is being carried out quarterly at 400kV Kalwa S/S. The last

thermography was done in October 2008, but hot spot was not detected at that time.

All the affected lines and equipments were restored by 14:42hrs on 12.12.2008.


Committee felt that the load of 600A on 400kV Kalwa-Lonikand line is not a

over load condition and under these loading the clamp should not have melted.

However the clamp might have melted due to improper tightening of the clamp

resulting in a sustained hot spot. Regular and rigorous thermo vision monitoring of

EHV S/S’s should be done to avoid such occurrences.

ITEM NO. 3: Tripping of lines / ICTs:

The incidences of tripping of lines and ICTs during the period 01-10-2008 to31-12-

2008 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: Follow up points:

5.01: Procurement of new Busbar protection scheme at 400 KV Nagda MPPTCL S/S:

PowerGrid had requested for early commissioning of Bus Bar Protection Scheme

at 400kV Nagda S/S in view of importance of the 400kV Nagda S/S in the WR grid.

During 103rd PCM, MPPTCL representative informed that Bus Bar protection panel of

Eassun Reyrolle make for 220kV side and REB 670 ABB make for 400kV side had

arrived at site. However due to failure of 315MVA transformer at Nagda S/S, the

commissioning of new busbar protection scheme was deferred and was expected to be

commissioned by first week of January 2009.

MPPTCL representative intimated that the new bus bar protection scheme

for 400kV and 220kV bus at 400kV Nagda has been commissioned in January 2009.

ITEM NO. 6: Other grid points:

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

emanating from PGCIL S/Ss to utilities.

(i) PGCIL representative informed that the PLCC scheme provided on feeders

connected to PGCIL at 220kV Pithampur and Rajgarh S/S’s had been

tested and put into service.

(ii) GETCO representative informed that the direct trip PLCC for 220kV

Bhilad-Vapi feeder has been commissioned.

(iii) MSETCL vide their letter No. SE/TCC/Vashi/297 dated 12 May 2008 had

informed that direct trip PLCC protection scheme for 220kV Boisar –

Boisar I & II feeders had been taken into service on 07.12.2007 and

09.05.2008 respectively at 220kV Boisar (MSETCL) S/S. He further

informed that the direct trip PLCC protection scheme in respect of

220kV Boisar (PGCIL) – Padghe feeder has been taken into service on

22.08.08.

(iv) PGCIL vide their letter No WRTS/O&M/R/141/175 Dt.14.01.09 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

Committee noted (i), (ii) & (iii). Since CSEB representative was not present, it

is requested that CSEB may intimate the present status of PLCC protection schemes

at (iv) to WRPC for needful.

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

In continuation with the discussion in the 101st, 102nd and 103rd meeting, the

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

WRPC.

It was decided that the data received regarding mal operation of the df/dt

relays would be analyzed by WRPC.

6.03: Non-availability of Event Logger at 400kV state owned sub-stations at

Nagda, Indore, Bina Padghe, Kolhapur, Koradi, Chandrapur, Dhule and

Bhilai.

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 CSEB are not provided. PGCIL have requested for

early installation of Event Loggers at these stations.

MPPTCL representative had informed that event loggers for Nagda, Indore and

Bina S/S are under procurement process.

MSETCL representative informed that event logger for Dhule, Kolhapur, Koradi

Padghe and Chandrapur S/S’s is covered under SMS program. The work of installation of

event loggers is in progress and the same will be completed within six months.

Committee requested the constituents for early action in this matter.


6.04: Pending SOE connections and erroneous data in SCADA.

The matter was first discussed in the 102nd PCM, the details of which are given in

the minutes of the meeting.

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.

Committee requested WRLDC to circulate the list of the locations from

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

to be established so that further action can be taken up.

6.05: Voltage dip on 220kV Bus at KAPS due to faults on remote lines.

NPCIL vide their letter No KAPS/EMU/BMS/2009/06 Dtd. 02.02.2009 have

informed that on 28.09.2008 a severe dip in voltage i.e. upto 138kV for 2 cycles was

recorded at KAPS 220kV Buses, due to tripping of Vav-Ichhalpur line. The 220kV KAPS-

Vav- 1 & 2 lines recorded a current of 2.35kA. Similar severe dip in volatage of upto 95kV

for 50msec was recorded on 31.01.2009 at KAPS for fault on Vadodara-Gotri Ckt.

No representative form NPCIL – KAPP was present during the meeting. GETCO

representative stated that fault was close to Vav substation on the feeder. Executive

Engineer (Protection) , WRPC stated that as per the short circuit studies for a 1PSG bus

fault at Vav s/s, the KAPP voltage dropped in simulation to 58%. The present drop was

around 63% which is in line with the expected results.

6.06: Review of 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 prepaired 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.


Executive Engineer (Protection) suggested that the WRPC protection manual

would be circulated among the members for review and their comments may be sent to

WRPC.

Committee agreed and opined that the comments may be discussed in the

forthcoming PCM.

ITEM NO. 7: 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 has been 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.

Member Secretary WRPC told that the 1st Study Group Meeting was held at

WRPC Mumbai on 11.11.08 and the 2nd Meeting was held on 3rd March 2009. The

draft report on the disturbance is in the finalization process and the report will be put

up in the Protection Committee Meeting.

ITEM NO. 8: Any other issues:

PGCIL vide their letter No.WRLDC/GrMgt Dtd.06.03.2009 have informed that the

network system in eastern part of the grid around Korba/Raipur areas is continuously

critically loaded and during planned outage of lines is causing severe over loadings on the

400kV and 220kV lines. Till the system strengthening is done in this area a Special

Protection Scheme (SPS) may be devised and implemented in this area.

Committee requested WRLDC to submit a draft scheme that may be discussed

in the next PCM meeting.


ITEM NO. 9: Date and Venue of the next meeting.

It was decided that the next protection committee meeting (105th) will be held at

WRPC Mumbai in May 2009, wherein system disturbances for the period

01/01/2009 to 31/03/2009 will be discussed. The exact date will be communicated

separately.


ANNEX-I

LIST OF PARTICIPANTS

104th Protection Committee Meeting held on 26th & 27th March, 2009 at NTPC Vindhyachal

MSETCL (Maharashtra State Electricity Transmission Company Limited)

Shri D.P. Nandanwar Dy. Executive Engineer (TCC), Vashi

MAHAGENCO (Maharashtra State Power Generation Company Limited)

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

MPPTCL (Madhya Pradesh Power Transmission Corporation Limited)

Shri B.K. Tripathi Addl. Superintending Engineer (Testing)

MPPGCL (Madhya Pradesh Power Generation Corporation Limited)

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

GETCO (Gujarat Energy Transmission Corporation Limited)

Shri R.D. Naik Addl. Chief Engineer (Testing), Baroda

Shri J.N. Pancholi Ex.Engr.(T)

GSECL (Gujarat State Electricity Corporation Limited)

Shri U.D. Adhvaryu Superintending Engineer (Testing), Baroda

NTPC

Shri Jitendra Tiwari DGM (EM)-I/c, VSTPS, Vindhyachal

Shri Anil Shrivastav DGM (EM), VSTPS, Vindhyachal

Shri K.S. Singh Srenior Superintendent, VSTPS, Vindhyachal


NPCIL (Nuclear Power Corporation of India Limited)

Shri Vivek M. Daptardar SME(E), TAPS, NPCIL

PGCIL (Power Grid Corporation of India Limited)

Shri P.Biswas Manager, WRLDC Mumbai

Shri Anand Dubey Manager, WRTS-II, Vadodara

Shri Ravi Wadyalkar Dy.Manager, WRTS-I, Nagpur

TPC (Tata Power Company)

Shri M.V.Kini Assist. Gen. Manager(ET &A), Trombay, Mumbai

Torrent PowerShri Shailesh K. Bhatt Manager(Transmission), Ahmedabad.

WRPC (Western Regional Power Committee) Shri P. Patel Member Secretary

Shri S. Satyanarayan Executive Engineer (P)

Shri P.D.Lone Assist.Dir.-I(P)


ANNEXURE-3

TRIPPINGS OF LINES / ICTS

Tripping Restoration Sr. No.

Name of S/S

Name of line/ICT

SYSTEM /Provision

of A/R (Yes/No)

Date Time Date Time REASON

3.01

400kV Kasor

400kV Kasor-GPEC

GETCO (Y) 01.10.08 5:49 01.10.08 5:56

Tripped from both ends on T-Ph Zone-1. A/R successful at GPEC end. A/R unsuccessful at Kasor endTransient tripping

3.02

400kV Bina

400kV Bina-Nagda 2

PGCIL (Y) 02.10.08 16:20 02.10.08 16:35

Main & Tie breaker tripped at Bina end, due to spurious direct trip command received from Nagada end, however line remained charged from Nagda end.

3.03

400kV Asoj

400kV Asoj-Amreli GETCO

(Y) 04.10.08 13:58 04.10.08 14:02

Tripped from both ends on R-Ph Zone-1. A/R successful at Amreli end. A/R L/O at Asoj end.Transient tripping

3.04

400kV Jabalpur

400kV Vindhyachal-Jabalpur 4

PGCIL (Y) 04.10.08 15:04 04.10.08 21:27

A/T from ends on receipt of direct trip from NTPC V'chal, due to operation of NGR OTI trip at VSTPP end. A/R was kept in Non-Auto mode at both ends for PID testing. OTI of NGR replaced with spare one.

3.05

400kV Indore

400kV Indore-Asoj 2

PGCIL (Y) 04.10.08 16:35 04.10.08 18:49

Tripped from both ends on transient fault. A/R unsuccessful due to low air pressure L/O of ABCB.

3.06 220kV KAPS

220kV KAPS-Vapi-1

NPCIL (N) 05.10.08 14:04 05.10.08 14:59

Tripped at local end on Zone-1, A-Ph , carrier Aided trip & remote end Zone-1

3.07

400kV Bhilai

400kV Bhilai-Seoni

CSEB (Y) 06.10.08 9:32 07.10.08 13:25

Line tripped on Main-I&II Z-1(B-N) operation..F/L-71.04km from Bhilai end. A/R L/O. Also 86Y(Type VAJ) was found burnt due to sticking up of Yph Micom relay (M-1) trip contact.

3.08

400kV Satna

400kV Vindhyachal-Satna 3

PGCIL (Y) 06.10.08 10:13 06.10.08 12:10

A/R at Satna end and after 3sec DT received from V'chal (NTPC) end, hence 3 ph tripped operated and main & tie CB tripped F/L 148km from Satna end. Transient Y-ph to E fault. A/R problem at V'chal end due to hydraulic pump pressure problem


3.09

400kV Bhilai

400kV Bhilai-Koradi

PGCIL (Y) 07.10.08 0:27 07.10.08 4:56

Line tripped on 186A,186B,30C,85 LO at Bhilai end and 186A,186B,27RZ, VAJ-30BR & LO trip at Koradi end, due to shorting of reactor WTI trip terminals at TB due to carbonisation at Koradi end, the trip command through carrier was extended to Bhilai end.

3.10

400KV SGTPS, Substation, Birsinghpur

SGTPS-Damoh Line MPPTCL

Y 07.10.08 12.2 07.10.08 15.19

500 MW Unit tripped on Stand by GT, E/F protection. SGTPS-damoh line conductor broken.

3.11 400kV Nagda

400kV Bina-Nagda 1

PGCIL (Y) 07.10.08 13:21 07.10.08 13:21

A/R successful at both ends on transient B-ph fault.

3.12 400kV Chandrapur

400kV C'pur-Parli Ckt-1

MSETCL Y 07.10.08 15:53 07.10.08 22:20

L/O trip at C'pur end on receipt of DT signal due to Bus fault because of falling of IPS tube at Girvasi S/S

3.13 400kV Chornia

400kV Chornia-Asoj GETCO

(Y) 08.10.08 0:55 08.10.08 1:21 O/V stage-II optd., at 400kV Asoj end.

3.14 400kV Jabalpur


PGCIL (Y) 08.10.08 11:04 08.10.08 11:25

A/T at VSTPP end only due to receipt of D/T from Jabalpur end due to DC earth leakage.

3.15 400 KV Bhatapara

400 KV Bhatapara-Korba

PGCIL (Y) 08.10.08 12:48 08.10.08 14:02

Line tripped due to PLCC mal-operation at Bhatapara.

3.16

400kV Bhilai

400kV Bhilai-Korba(W)

CSEB Y 08.10.08 15:31 08.10.08 16:19

Line tripped on Main-I&II Z-1(C-N) operation..F/L-113.8km from Bhilai end. A/R L/O. Transient fault.

3.17 400kV Nagda

400kV Nagda-Indore

MPPTCL Y 09.10.08 2:15 09.10.08 19:35

Main-I&II protn.optd., ANZ-2, A/R L/O.

3.18 400 KV Raigarh

400 KV Raigarh - Rourkela # 1

PGCIL (Y) 10.10.08 06:30 10.10.08 08:23

Line tripped due to operation of Buchholz protection at Rourkela end.

3.19

400kV Bhilai

400kV Bhilai-Seoni CSEB

Y 11.10.08 11:53 11.10.08 12:41

Line tripped on Main-I&II Z-1(B-N) operation..F/L-71.18km from Bhilai end. A/R L/O. Transient fault.


400 KV Bhatapara-Korba

PGCIL (Y) 11.10.08 15:43 11.10.08 16:39

Line tripped due to PLCC mal-operation at Bhatapara.

3.21

400kV Indore

400kV Indore-Asoj 1

PGCIL (Y) 13.10.08 11:26 13.10.08 12:34

Line tripped from both ends on transient fault. A/R unsuccessful due to low air pressure.

3.22 400kV Asoj

400kV Asoj-Ukai GETCO

(Y) 13.10.08 11:48 13.10.08 12:03 Tripped from both sides on Y-Ph-N Zone-1 from both ends.Transient tripping


3.23 400kV Asoj

400kV Asoj-Ukai GETCO

(Y) 13.10.08 13:08 13.10.08 20:45 Tripped from both ends on B ph-N Zone-1.Nothing abnormal found during patrolling.

3.24 400 KV Boisar

400 KV Boisar-Vapi

PGCIL (Y) 13.10.08 13:18 13.10.08 13:43

Line tripped on B - N Fault at 16 km from Boisar.

3.25 400kV Rajgarh

400/220kV ICT 1 PGCIL

(Y) 13.10.08 19:35 13.10.08 21:17 ICT tripped due to thermal overload. Approx. Load on ICT before tripping 234MW

3.26 400kV Rajgarh

400kV Rajgarh-Khandwa 2

PGCIL (Y) 14.10.08 15:28 14.10.08 16:17

Line tripped due to persisting Y ph-E fault. A/R L/O.

3.27

400kV Bhilai


Y 19.10.08 9:04 19.10.08 10:11


3.28

400kV Bhilai


Y 19.10.08 12:32 19.10.08 13:14


3.29 400 KV Boisar

400 KV Boisar - Padghe

PGCIL (Y) 19.10.08 14:04 19.10.08 14:04

Line successfully Auto-reclosed on Y - N fault.

3.30 400kV Bhilai

400kV Bhilai-NTPC-1

CSEB Y 20.10.08 11:33 20.10.08 11:57

Line tripped on opening of 186A,186B, 85LO.

3.31

400kV Satna

400kV Satna-Bina 4

PGCIL (Y) 20.10.08 12:29 20.10.08 19:19

A/T due to Ph-Ph (R-Y-E) fault Fault Loc.-52Km from Satna end.Tie CT of Y-ph blasted. First Y ph fault appeared & after 1sec R ph-E fault appeared. A/R unsuccessful.

3.32

400kV Nagda

400kV Nagda-Rajgarh ckt-II

MPPTCL Y 23.10.08 9:47 ??? ???

Y-ph pentagrph fell on 400kV Bus-II at Nagda S/S


400 KV Bhatapara - Korba

PGCIL (Y) 23.10.08 10:23 23.10.08 10:39

Line tripped due to PLCC maloperation at Bhatapara end



PGCIL (Y) 23.10.08 11:18 23.10.08 11:57

Line tripped due to PLCC maloperation at Bhatapara end

3.35 400kV Nagda

400kV Nagda-Rajgarh ckt-I

MPPTCL Y 24.10.08 12:25 24.10.08 14:24

Main-II protn.optd, A/R L/O.



PGCIL (Y) 25.10.08 13:15 25.10.08 13:25

Line tripped due to Wiring problem of Phase auto reclosure relay in the panel.

3.37

400kV Khandwa


PGCIL (Y) 28.10.08 14:04 30.10.08 10:15

DT received due to over voltage protection optd., at Rajgarh end. Voltage before tripping 429kV at Khandwa end.


3.38

400kV Chandrapur

400kV C'pur-Parli Ckt-1

MSETCL Y 31.10.08 5:27 31.10.08 16:38

Line A/R but went into L/O due to persistant fault (B-N). No abnormality found during patrolling.

3.39 400kV Asoj

400kV Asoj-Wanakbori GETCO

(Y) 05.11.08 3:47 05.11.08 4:59 Tripped from both ends on Ph-Ph fault. No abnormality found during patrolling.

3.40 400kV Asoj

400kV Asoj-Chorania

GETCO (Y) 05.11.08 15:22 05.11.08 15:22

Tripped on R Ph-E Zone-1. A/R operated successfully.

3.41 400kV Khandwa

400kV Itarsi-Khandwa 2 PGCIL

(Y) 14.11.08 6:04 14.11.08 6:27 O/V protection optd., at Khandwa end. Voltage before tripping 438kV at Khandwa end.

3.42 400kV Kasor

400kV Kasor-SSP

GETCO (Y) 14.11.08 6:05 14.11.08 6:30

Over voltage at 400kV SSP end (435kV)

3.43 400kV Kasor

400kV Kasor-SSP

GETCO (Y) 18.11.08 4:43 18.11.08 5:12

Over voltage at 400kV SSP end.

3.44

400KV Satpura Sub-Station (Sarni)

400kV Sarni-Indira Sagar Line

MPPGCL (Y) 18.11.08 9.43 18.11.08 9.58

Gr.A/B Lock-out relay operated Indication – Direct trip received from remote end Remote end indication -Gr.A/B trip relay operated Zone-1/II Bus Bar protection operated at Indira Sagar end.

3.45 400kV Jabalpur


PGCIL (Y) 21.11.08 2:14 21.11.08 2:50

RAZFE relay mal-operated due to module damaged at V'chal end. CR at Jabalpur end.

3.46 400kV Jabalpur

400kV Jabalpur-Itarsi 4

PGCIL (Y) 26.11.08 17:54 26.11.08 18:27

A/T due to receipt of DT because of blasting of Y-ph of CSR at Itarsi end.

3.47 220kV Boisar

220kV Boisar-Tarapur

PGCIL (Y) 27.11.08 06:02 27.11.08 07:54

Line tripped on transient fault.

3.48

400 KV Kolhapur

400 KV Kolhapur-Mapusa # 1 PGCIL

(Y) 28.11.08 10:38 28.11.08 11:11

Line CB tripped only at Kolhapur end due to DC Earth Leakage during SMS work at Kolhapur. Line remained in charged condition from Mapusa.

3.49 400kV Khandwa


PGCIL (Y) 29.11.08 10:07 29.11.08 10:04

O/V protection optd., at Rajgarh end. Voltage before tripping 423kV at Khandwa end.

3.50 400kV Nagda

400kV Nagda-Rajgarh ckt-I

MPPTCL Y 07.12.08 10:18 07.12.08 11:18

O/V protn. Optd.

3.51 400kV Jabalpur


PGCIL (Y) 07.12.08 17:44 07.12.08 20:52

A/T at both ends on R & Y ph-ph fault. F/L=67% from J'pur end.

3.52

400kV Jabalpur

400kV Vindhyachal-Jabalpur 1 PGCIL

(Y) 08.12.08 11:05 09.12.08 17:43

A/T at both ends on R & Y ph-ph fault. Test trial taken at 14:55hrs but tripped again on SOTF. At Loc.No.367 Yph top jumper was found broken and hanging on middle (Rph).


3.53 400kV Kasor

400kV Kasor-SSP

GETCO (Y) 10.12.08 5:06 10.12.08 7:31

Over voltage at 400kV SSP end (433kV)

3.54

400 KV Tarapur

400 KV Tarapur - Padghe # 1 PGCIL

(Y) 12.12.08 18:52 12.12.08 21:21

Line tripped due to direct trip command sent to Tarapur end, due to problem in the new SCADA system installed at Padghe end.

3.55

400 KV Tarapur

400 KV Tarapur - Padghe # 2 PGCIL

(Y) 12.12.08 18:52 12.12.08 20:13

Line tripped due to direct trip command sent to Tarapur end, due to problem in the new SCADA system installed at Padghe end.

3.56

220kV TAPS

220kV TAPS-Boisar

NPCIL 14.12.08 16:30 14.12.08 18:26

Tripped on R,Y,B Ph Zone-2 indication. Flashover of R,Y,B LA's of 150MVA T/F at Boisar(MSETCL) S/S.

3.57 400kV Satna

400kV Satna-Bina 4

PGCIL (Y) 26.12.08 3:36 26.12.08 3:36

A/R successful at both ends on transient B-ph to E fault.

3.58 Deleted


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.

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 Nagpur, Nasik and Vashi Circles. PGCIL have implemented the recommendation except on 400kV Indore-Asoj line which will be done within 2 months.


GETCO have implemented the recommendation except two fdrs. Viz. 400kV Choradia-Hadalia & Choradia-Jetpur. It was decided 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.

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 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

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


schemes is stored in either of the relay.

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 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.

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 104th PCM GETCO informed that it will implement within one month

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

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.

MSETCL informed

that data down

loading facility from

numerical relays has

been included in their

Substation Monitoring

Schemes (SMS) and

would be made

available. Vashi,

Nasik and Nagpur

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.

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.

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

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 feature being presently used.

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.

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

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

Representative of MAHAGENCO informed that the matter is still in discussion stage at H.O. Mumbai and MAHAGENCO will inform the committee about any development. Protection Committee requested MAHAGENCO to expedite the action.


disturbance. WRPC may work out a suitable scheme in consultation with MSETCL

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.


f-3, midc area, andheri (east), mumbai - 400 093 … · committee observed that the operation of...

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