baart sarkar government of india kond`iya ivavut p ... · agenda of 103rd wrpc pcm 2.02: 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- 28200194, 28200195; 28200196; fO@sa Fax : 022 – 28370193 Website : www.wrpc.gov.in E-mail : [email protected]

¬¸¿.:œ¸®¸½¢¨¸¬¸/£®¸μ¸/£®¸μ¸ ¬¸.ˆÅú 103¨¸ì ¤¸¾“ˆÅ /2008/ ¢™›¸¸¿ˆÅ: No.: WRPC/Prot./ 103rd PCM/2008/11765-804 Date:21.11.2008 ¢¨¸«¸¡¸ : œ¸® ½̧¢¨¸¬¸¢Ÿ¸¢÷¸ ˆÅú £®¸μ¸ ¬¸¢Ÿ¸¢÷¸ ˆÅú 103 ¨¸ì ¤ ¾̧“ˆÅ ˆÅ¸¡ Ä̧¬ »̧�¸ú— Sub. : Agenda of 103rd WRPC, Protection Committee Meeting.

ƒ¬¸ œ¸°¸ ½̂Å ¬¸¸˜¸ œ¸® ½̧¢¨¸¬¸¢Ÿ¸¢÷¸ ˆÅú 103 ¨¸ì £®¸μ¸ ¬¸¢Ÿ¸¢÷¸ ˆÅú ¤ ¾̧“ˆÅ, �¸ ½̧ ¢ˆÅ ¢™›¸ ¿̧̂ Å 12 ‡¨ ¿̧ 13 ¢™¬¸Ÿ¤¸£ 2008 ˆÅ ½̧ 10.30 ¤¸� ½̧ ’»¥¸ú ’¸ƒŠ¸£ ¢£¬¸ Á̧’Ä, ˆÅ¸›í¸ ›¸½©¸›¸¥¸ œ¸¸ˆÄÅ (›¸¸Š¸œ¸º£ ¬¸½ 250 ¢ˆÅ.Ÿ¸ú. ™»£) œ¸¸¨¸£¢ŠÏ” ×¸£¸ ‚¸¡¸ ½̧¢�¸÷¸ ˆÅú �¸¸› ½̧ ¨¸¸¥¸ú í¾, ˆÅú ˆÅ¸¡¸Ä¬¸»�¸ú ¬¸¿¥¸Š›¸ í¾ — £®¸μ¸ ¬¸¢Ÿ¸¢÷¸ ˆÅú 103 ¨¸ì ¤ ¾̧“ˆÅ ˆÅú ˆÅ¸¡ Ä̧¬ »̧�¸ú œ¸® ½̧¢¨¸¬¸ ˆÅú ¨ ¾̧¤¸¬¸¸ƒ’ Ÿ ½̧¿ ž¸ú „œ¸¥¸¤š¸ í¾ — œ¸¸¨¸£¢ŠÏ” ×¸£¸ ¢™›¸¸¿ˆÅ 11.12.2008 ˆÅ¸½ ™¸½œ¸í£ 1.30 ¤¸�¸½ ›¸¸Š¸œ¸º£ ¬¸½ ˆÅ¸›í¸ ˆ½Å ¢¥¸‡ œ¸¢£¨¸í›¸ ˆÅú ¨¡¸¨¸¬˜¸¸ ˆÅú Š¸ƒÄ í¾ —

ˆ¼Åœ¸¡¸¸ ¤¸¾“ˆÅ Ÿ¸½¿ ž¸¸Š¸ ¥¸½¿ — Please find enclosed herewith Agenda of 103rd Protection Committee Meeting of WRPC, to be held on

12th & 13th December 2008 at Tuli Tiger Resort, Kanha National Park (250 K.M. away from Nagpur) hosted by POWERGRID. The contact details of the co-ordinating officers for arrangements (transport /accommodation etc.), is as follows: Name Designation Mobile No. Phone No. e-mail address Sh.S. Suresh Dy. Manager 09423762519 0712-2641478 [email protected] Sh. Ravi Wadyalkar

Dy. Manager 09423762547 0712-2641479 [email protected]

In case of any difficulty in co-ordination, Shri S.K. Mishra, Dy. General Manager (O & M), Mob.No.:09422811660 may please be contacted. Transport arrangement from Nagpur is made on 11.12.2008 at around 01.30 pm by POWERGRID.

Agenda of 103rd PCM is also available on WRPC website (i.e.www.wrpc.gov.in).

Kindly make it convenient to attend the meeting.

ž¸¨¸™ú¡¸ / Yours faithfully, ‚›¸º¥¸Š›¸ˆÅ : ¡¸˜¸¸½œ¸¢£ Encl: As above (‡¬¸.”ú.’¸ˆÅ¬¸¸¿”½/S.D. Taksande) ‚š¸ú®¸μ¸ ‚¢ž¸¡¸¿÷¸¸ (£.) / Superintending Engineer (P.)

Agenda of 103rd WRPC PCM

AGENDA FOR THE 103rd PROTECTION COMMITTEE MEETING

Item No.1: Confirmation of Minutes of 102nd Protection Committee Meeting.

Minutes of 102nd PCM held on 17th & 18th Sept.2008 at Ahmedabad, were circulated vide

WRPC letter no. Prot./102-PCM/2008/WRPC/10008 dated 06th October 2008. Comments

have been received from NPCIL vide their letter no. NPCIL/Trans./2008/M/134 Dt

23.10.08 and PowerGrid vide their letter No. WRTS/O&M/R/141/860 Dt.27.10.08,

regarding Item No.6.03 of the minutes.

Copies of these letters are placed at Annex. 1A & 1B.

Committee may discuss.

Item No.2: System disturbances

2.01: System disturbance at Gandhinagar TPS in GSECL system on 03-07-2008

On 03-07-2008 at 14:50 hrs, while taking planned shut down of Unit No.5 (connected to

Bus A) for AOH , at Gandhinagar TPS, Local Breaker back-up (LBB) protection of GT-5

operated and consequently Bus Bar protection operated for Bus A, due to which all the

220kV Lines, Transformers, Generators connected to Bus A and Bus Coupler tripped on

operation of bus bar tripping relays 96.

Their was a delayed opening of Y pole of the Unit No.5 Circuit Breaker. CGL engineer

was called for attending the problem. Measurement of the Circuit Breaker timings was

carried out and timings were found same for all the three phases.

The LBB relay and subsequent operation of Bus bar protection of Bus A needs to be

investigated.

220 kV Bus A was charged at 15:15 Hrs. & 220 kV Lines, Transformers and Generators

were taken in service by 19:12hrs of 03.07.08, except Generator 5(under AOH) which

was taken into service at 01:50hrs on 22.07.08

Report received from GSECL is enclosed at Annex- 2.01.



2.02: System disturbance at 220 KV Haldarwa S/S in GETCO system on 10-07-2008

On dated 10.07.2008 at 15.55 hrs .there was a heavy noise on 132kV side of switchyard

in 220kV Haldarwa S/S resulting in tripping of 220kV lines and transformers.

Bus Bar Protection (EE make, PBDCB type) blocked LED indication appeared on the

Bus Bar Protection Panel. All the feeders connected to Haldarwa S/S tripped from remote

ends.

During yard inspection the C.T cable from J.B to M.K box of 220kV GPEC -1 Line was

found grounded (i.e. between cores and core to ground), this might have resulted in

blocking of bus bar scheme. Also there was a transient fault on the 220kV GPEC -1 Line,

which was not cleared from Haldarwa end due to shorting of C.T cable of 220kV GPEC-

1 Line. It was cleared from GPEC end.

All the feeders connected (Bus-1 and Bus-2) to Haldarwa S/S fed the fault, since the bus

coupler breaker was in service. Though the fault was on Bus section 1 at 220 KV

Haldarwa S/s, the Bus Bar Protection scheme could not clear the fault since it was in

blocked condition.

From the DR data of Kawas-1 it is evident that the fault was on 220 kV Bus (reverse

zone) and it has taken 391.7 m sec to clear the fault. The fault might have been highly

resistive.

IR values of R & B ph LA of 100MVA 220/132kV EMCO make T/F. No.1, were found

low (i.e.250 M ohm) also IR value of R ph LA of 100MVA 220/132kV EMCO make T/F

No.2, was found low (i.e. 250 M ohm). The LA’s were replaced.

The fault level at Haldarwa S/S is 43.52 kA and the maximum setting available with the

Bus Bar Protection scheme is less than the corresponding fault current of 30kA.

All the tripped Lines and transformers were restored by 19:05hrs. on 10.0708, except T/F

No 2, which was restored at 20:40hrs on 11.07.08

Report received from GETCO is enclosed at Annex- 2.02.



2.03 System disturbance at Kutch Lignite Thermal Power Station (KLTPS) in GSECL system on 25-07-2008 On 25-07-2008 at 06:55 Hrs. Bus I Differential protection operated (with indication R,U),

due to which all the 220kV lines, transformers and generators connected to Bus I, tripped

on operation of bus bar tripping relays 96, at KLTPS

The R phase insulator of 89A isolator of Akrimota line – 1 was flashed. The weather was

cloudy and huge chattering was observed during above tripping.

220 kV Bus I Charged at 07:20 Hrs, and all the equipments were restored by 09:20hrs,

except 220kV Akrimota line – 1 which was restored at 18:45hrs on 25.07.08, after

replacing the defective insulator.



2.04: System disturbance at Sikka Thermal Power Station in GSECL system on 27-07-2008

On 27.07.2008 at 05:40Hrs, sound of flashover was heard and simultaneously the Bus Bar

Differential protection of Bus B operated resulting in tripping of all lines, transformer,

generators and Bus Coupler connected to Bus B at 132kV Sikka TPS

During yard inspection it was found that the flexible jumper of 89 C Bus side isolator of

132kV Bhatia line was melted and was found disconnected. This disconnected jumper

might have touched to ground resulting in a Bus B fault.

The flexible jumper was replaced and all such jumpers were tightened.

All the tripped feeders and equipments were restored by 08:53Hrs of 27.07.08.




2.05: System disturbance at 220kV Morbi S/S in GETCO system on 28-07-2008

On 28-7-2008 at 3:40 hrs, 220 kV Dhangdhra - Morbi and 220 kV Hadvad – Morbi

lines, emanating from 220kV Morbi S/S developed line faults simultaneously. There

was a Y and B Ph fault (Disc insulator failure at @ 6 Km from Morbi) on 220kV

Dhangadhra line and R & B Ph. Fault (disc insulator failure at @ 13 Km from Morbi) on

220 kV Halvad line.

220 kV Morbi Halvad line tripped from both ends correctly. 220 kV Morbi- Dhangadhra

scheme operated in zone 1 from Morbi end, and on carrier trip at Dhangadhra end, but all

the three poles of breaker did not open simultaneously at Morbi S/S. The B –Ph pole

opened after a delay of 268 m sec, as seen from the DR data of 400kV Hadala S/S. The

pole discrepancy timer setting is 500 m sec and LBB operation time setting is 200 m sec.

Before the breaker could trip on pole discrepancy, LBB operated and tripped all the lines

connected to Morbi S/s, resulting complete failure of supply.

Since there is single bus arrangement at 220 kV Morbi S/S, LBB scheme has been put in

service to clear the bus fault faster.

GETCO may please furnish the restoration details.

Report received from GETCO is enclosed at Annex- 2.05.


2.06: System disturbance at 400 kV Nagda S/S in MPPTCL system on 29-07-2008

On 29.07.2008 at 03:28Hrs, BHEL make 400/220kV, 315MVA transformer commissioned

at 400kV Nagda S/S on 28.05.1992, tripped from both sides. At the time of tripping no

other tripping occurred at 400kV Nagda S/S or remote S/S’s. Simultaneously the

transformer bushing caught fire causing complete damage to the T/F. To avoid damage to

the protection-relaying panel, the control panel D.C supply was switched OFF. The breaker

control cables of 220kV breaker, which were laid in the same trench used for this ICT got

burnt due to the fire. The data downloaded from the AREVA make. P633 Numerical

Differential Relay, indicated that the T/F tripped on Differential protection in 79 msecs.

During routine maintenance in the month of April 2008, the T/F was tested and the test


results were satisfactory.

Replacement of the faulty T/F is in progress and will be commissioned by the end of

December 2008.

Report received from MPPTCL is enclosed at Annex- 2.06.


2.07 : System disturbance at 220kV Gavasad S/S in GETCO system on 09-08-2008.

On 09.08.2008 at 4.15 hrs, 220kV feeders on Bus A and Bus coupler breaker tripped at

220kV Gavasad S/S. There was no zone indication on Bus bar panel. The trip signal was

persistent and was not getting resetted.

There was no actual bus fault. The relay modules were removed for inspection. Lot of

waste of mice & lizard was found in measuring and tripping modules of zone –A of

RADSS scheme. The terminals meant for final tripping of zone-A were found shorted.

The modules of Zone –A bus bar were thoroughly cleaned. Also the bus bar protection

relay panels were cleaned thoroughly. Proper vermin proofing is also done

The scheme was tested for Zone A operation by injecting current. The scheme was put

under observation on 09/08/08.

All the feeders were transferred on Bus B to attend the isolator operating and alignment

problems. On completion of Isolator problems by 25/8/08 the feeders will be transferred

on Bus A.

Report received from MPPTCL is enclosed at Annex- 2.07.


2.08: System disturbance at 220 kV Khaparkheda S/S in MSETCL system on 10-08-2008

On 10.08.2008 at 01:25Hrs, the Y Phase CT (ABB make, Year of Manufacture 1999,

Commissioned on 16.02.2006), caught fire and got burst, at 220kV Khaparkheda S/S. All

the feeders, Gen Unit 2, Gen Unit 3, Station T/F 2(40MVA) and Station T/F 3 (40MVA)


connected to 220kV Bus-I, including bus coupler, tripped at Khaperkheda S/S, on

operation of Zone-I, bus bar protection. 250MVA GT1 which was connected to 220kV

Bus-II, also tripped due to failure of auxiliary A.C. supply of this GT. The auxiliary supply

to GT1 was fed through T/F 2, since its own station T/F (T/F-1) was under outage for

maintenance. The 220kV Khaperkheda-Kalmeshwar feeder tripped on DPS Zone-I from

Kalmeshwar end. Due to bursting of Y phase CT mechanical damage to R,Y, and B phase

CVT’s and R and B phase CT’s was observed. All damaged CVT’s and CT’s were

replaced.

Normalcy of all the feeders and Generating units was restored at 08:04hrs on 10.08.2008,

except 220kV Kalmeshwar bay, which was restored at 23:06hrs on 12.08.2008.

Report received from MSETCL is enclosed at Annex- 2.08.


2.09: System disturbance at 220 kV TAPS S/S in NPCIL system on 05-09-2008.

On 05.09.2008 at 07:07hrs, the R-Phase tension/suspension insulator string flashed over at

low level gantry just before take off tower of 220kV TAPS-Bhilad Line at TAPS 1&2

swichyard. 220kV Zone-1 Bus Differential relay operated for the nearby through fault on

220kV TAPS-Bhilad feeder. The DPS at TAPS end had operated in Zone-1 and Dir E/F

and DPS Zone-2 at other end, however all the lines and Gen.Unit-2 tripped at TAPS.

The 220kV Bus Bar Differential relays are 40 years old.

It was raining and lightening at the time of occurrence.

Restoration details may please be furnished by TAPS.

Report received from TAPS is enclosed at Annex- 2.09.



2.10: System disturbance at 400 kV Padghe S/S in MSETCL system on 23-09-2008.

On 23.09.2008 at 00:49hrs, the 400kV side Y phase CT of 3x105MVA, 400/220/33kV ICT

No.1, connected to Main Bus-II failed at 400kV Padghe S/S. ICT No.-1 tripped on

operation of Differential protection, simultaneously the 400kV Main Bus-II bus bar

protection operated resulting in tripping of all the equipments connected to Main Bus-II.

Tan delta results of the 400kV BHEL make(YOM:1998, repaired and commissioned on

22.03.07) Y phase CT were satisfactory.

The 400kV Padghe-Tarapur-I line which was connected to 400kV Main Bus-I also tripped

on mal operation of distance protection relay (THR-ER make) on “LC-line check (SOTF)

feature” at Padghe end. The 400kV Padghe-Boisar (PGCIL) which was connected to Main

Bus-II, did not trip at Boisar end on DT signal due to operation of busbar protection at

Padghe S/S.

All the affected lines and equipments were restored by 11:42hrs on 23.09.2008.

Report received from MSETCL is enclosed at Annex- 2.10.


2.11: System disturbance at 400 kV Korba (W) S/S in Chatiagarh system on 29-09-2008

On 29.09.2008 at 12:59 hrs 220kV Korba (W)-Mopka S/C tripped on R-phase fault. The

line was carrying about 220MW just before the tripping. The 400/220kV, 500MVA ICT at

Korba (W) was loaded to about 350MW (from 220kV to 400kV) just before the above

tripping. The above ICT got critically loaded to 566MW consequent to tripping of 220kV

Korba (W)-Mopka Ckt, and tripped on overload leading to tripping of 220kV lines

connected to it.

The above trippings resulted in islanding of Korba (E)-Raigarh-Mopka-Banari-Bemetara-

Kotmikla areas of Chattisgarh system with a generation of 1100MW and a load of about

450MW. The island frequency rose to 51.99 Hz due to excess generation of around

650MW and the frequency of the N-E-W grid dipped to 49.15 Hz from 49.36Hz (prior to

islanding) and then to 48.8Hz due to loss of around 650MW of import from the island.

Due to the tripping of all the evacuating lines from IBTPS, both the IB units tripped. Due


to high frequency in the island, the units K(E) Ext-1 (250MW) generating around 180MW,

K(E) Ext-2 (250MW) generating around 180 MW, K(E)-6 (120MW) generating around

80MW and Jindal-4 (250MW) generating around 200MW totaling to around 640MW

tripped on over frequency. With the tripping of these units, the generation in the island was

in the order of 500MW and the island survived.

The 400/220kV Korba (W) ICT was synchronized at 13:05hrs and the above island was

brought back into main grid.

Flash report received from PowerGrid is enclosed at Annex- 2.11.

CSEB is requested to furnish a detail report.


ITEM NO. 3: Tripping of lines / ICTs:

The incidences of tripping of lines and ICTs during the period 01-07-2008 to30-09-2008

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

discussed during the 102nd WRPC PCM held at Ahmedabad. The status as reported in

102nd PCM regarding implementation of the recommendations are placed at Annexure-4.

Committee may discuss and constituents may intimate the present status regarding

implementation of recommendations.


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 102nd 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 T/F

at Nagda S/S, the commissioning of new busbar protection scheme was deferred

and was expected to be commissioned by mid of December 2008.

MPPTCL may intimate the present status on commissioning of new busbar

protection scheme at Nagda.

5.02: Implementation of Revised Mumbai Islanding Scheme:

MSETCL vide their letter No.SE/TCC/Vashi/642 Dt. 04.11.2008 and Reliance

Energy vide their letter Dt. 05.09.08, have intimated that the revised Mumbai

Islanding Scheme, as recommended by the Enquiry Committee on Grid

Disturbance of 25th & 28th February, 2007, has been commissioned, tested and

taken into service at 220kV Boisar (MSETCL) S/S, on 19.10.2008.

The final scheme is placed at Annex.5.02

Committee may please note.

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) During the discussions in the 102nd PCM, MPPTCL representative had

informed that the PLCC scheme provided on feeders connected to PGCIL at

220kV Pithampur and Rajgarh S/S’s were suitable to transmit and receive


direct trip as well as permissive trip command. This had been tested while

charging the feeders and PGCIL had been communicated to test the scheme

and take into service, at their end.

(ii) GETCO representative informed that D.T. is not available for 220kV

Bhilad–Vapi feeders and the same will be provided by September 2008 end.

(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. Regarding direct

trip PLCC protection scheme in respect of 220kV Boisar(PGCIL) – Padghe

feeder, proposal had been sent to their Corporate Office and approval was

expected to be received by the end of September 2008, after due study at

their Corporate Office Mumbai.

Present status of above PLCC protection schemes may please be intimated.

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

The WRP Committee in its 7th meeting held on 3rd May 2008, had approved

revision of df/dt relay settings to be implemented w.e.f. 1st July 2008. In the 101st

PCM, members were requested to implement the following revised settings

approved by the WRP Committee, for which all the committee members had

agreed.

Stage Settings

(Hz)/(Hz/

Sec)

Total

Load

Relief in

Region

(MW)

Load shedding (MW) to be effected by

GETCO MPPTCL MSETCL CSEB TPC

Stage I 49.9/0.1 2000 1006 361 546 27 60

Stage II 49.9/0.2 2000 905 355 621 37 82

Stage III 49.9/0.4 2472 1001 392 686 120 273

Total 6472 2912 1108 1853 184 415


Matter was discussed in 102nd PCM and representatives of GETCO, MPPTCL,

CSEB and TATA power informed that the revised settings of df/dt ULFS relays

have been implemented. MSETCL representative informed in OCC meeting of

WRPC that the revised settings have been implemented in their region as well. But

constituents have intimated that these relays are prone to maloperation.

Committee may note the same and discuss about experience of maloperation

of these relays.

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

Nagda, Indore, Bina and Dhule.

PGCIL had informed that Event Loggers at some of the 400kV state owned Sub

stations, namely Nagda, Indore, Bina and Dhule 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 S/S is covered under

SMS program.

Present status of installation of Event Loggers at above S/S, may be intimated.

6.04: Pending SOE connections and erroneous data in SCADA. During the 102nd PCM Add.G.M WRLDC stated that, in the existing ULDC

scheme (SCADA/EMS system), at some of the locations in WR, the CB contacts

are extended to the SOE inputs of the RTU, while at many other locations the SOE

connections are yet to be established. In order to have the correct analog and status

data through the SCADA/EMS system it is advantageous to configure the MTR

contacts to the SOE inputs of the RTU. The MTR contacts extended to the SOE

inputs of the RTUs, will help in the analysis of grid disturbance and the time

logging will be independent of the CB operation timings in cases where the


SOE input to the RTU is taken from CB contacts.

Also the critical data both analog and status acquired from some of the locations is

found to be erroneous, due to which the results of power network analysis module

are not of very good quality.

Member Secretary WRPC, in 102nd PCM, stressed the importance of receiving,

correct time logging of tripping elements, correct status of elements and correct

analog data, through SCADA. He further requested constituents to take corrective

actions immediately and convey the compliance.

Committee may discuss for present status corrective actions taken in compliance

of the above.

6.05 : Current setting for LBB relay’s of 400kV Lines

Power Grid vide their letter No. WRTS/O&M Dt.14.11.08, have informed that on

11.11.08 Main-I & II of 400kV Koradi-Bhilai Line operated at Bhilai end, however

due to failure of the pneumatic system of the breaker the fault was not cleared for

around 3 minutes due to non operation of LBB relay within 200msec, since the fault

was of high resistance nature. Non operation of LBB relay in time is mainly due to

higher current setting of 1.2 Amps(corresponding to 1200Amps on Primary side),

adopted at Bhilai S/S

PowerGrid have suggested to change the LBB relay current settings from 1.2 Amps to

0.2Amps.

Letter received from PGCIL is enclosed at Annex.6.05

Committee may discuss the settings suggested by PowerGrid vis-à-vis practices

adopted by constituents and recommendations as given in C.B.I.P. manual.


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.

The 1st Study Group Meeting was held at WRPC Mumbai on 11.11.08. The outcome of the

1st Study Group Meeting would be discussed and finalized in the 2nd Meeting to be held in

the month of December 2008, as certain more information was sought from NTPC

Vindhyachal. The final report will be put up in the Protection committee Meeting,

thereafter for its approval.

ITEM NO. 8: Any other issues:

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


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

3.01 400 KV Kasor 400 KV Kasor-GPEC

GETCO Y 01.07.08 2:27 04.07.08 19:30

At Loc No.228(S) Y-Ph, Loc.No.209(S)R Ph & loc No.231(S) B-Ph disc insulator flash over..

3.02 400 KV Amreli

400 KV Amreli-Jetpur

GETCO Y 01.07.08 4:25 01.07.08 15:46 At Loc No.615(S)-B ph string

insulator flash over.

3.03 400 KV Kasor 400 KV Kasor-SSP

GETCO Y 02.07.08 3:06 02.07.08 21:55 At loc.no.117(S) R-Ph disc

insulator flashover.

3.04 400kV Nagda 400kV Nagda-Bina II

MPPTCL Y 02.07.08 3:21 02.07.08 10:05 Trip ckt. Sup., Gr. A&B of

REL Optd.

3.05 400kV Indore 400kV Indore-Asoj Ckt.-II

PowerGrid Y 02.07.08 5:37 03.07.08 18:13

Line tripped from Asoj end only, due to insulator flashover at Loc.No.758A.

3.06 400kV Indore 400kV Indore-Asoj Ckt.-I

PowerGrid Y 02.07.08 6:38 02.07.08 18:15 Line tripped from Asoj end

only, due to transient fault.

3.07 400kV Indore 400kV Indore-Asoj Ckt.-I

PowerGrid Y 04.07.08 4:17 04.07.08 9:15 Line tripped from both ends,

due to transient fault.

3.08 400kV Bhilai 400kV Bhilai-Koradi

PowerGrid Y 05.07.08 5:06 05.07.08 5:06 A/R successful at both

ends on R-N fault.

3.09 400kV Vindhyachal

400kV V'chal-Jabalpur Ckt.IV

PowerGrid Y 06.07.08 23:31 07.07.08 0:46

A/R successful at Jabalpur end but A/T due to receipt of D/T from VSTPP. B-E fault. Patrolling carried out no abnormality observed.

3.10 400 KV Asoj 400 KV Asoj-Indore-2

GETCO Y 10.07.08 4:20 10.07.08 4:50 A/R successful. Transient

tripping.

3.11 400kV Nagda

400kV Nagda-Dehgam Ckt.I

PowerGrid Y 10.07.08 13:01 11.07.08 15:07

A/T at both ends on R & Y ph-ph fault. Decapping of top(Yph) insilator string at Loc. No.324.

3.12 400kV Raipur 400kV Raipur-Sipat 3

PowerGrid Y 12.07.08 12:12 12.07.08 13:06

Line tripped at Raipur end on receipt of DT signal from Sipat end. Line tripping at Sipat end was on DPS. CVT problem at Sipat end.


3.13 400kV Bhilai 220kV Bhilai-PGCIL

CSEB 17.07.08 13:06 04.05.08 19:27

Line tripped on operation of DPR as well as LBB. Conductor snapped at Loc.No. 5 DA-0

3.14 400kV Nagda 400kV Nagda-ISP

MPPTCL Y 21.07.08 13:27 21.07.08 14:28 A/R L/O M-2 protn. Optd. On

Rph fault.


GETCO Y 24.07.08 13:38 24.07.08 21:35

A/R lock out at Kasor end. Nothing found abnormal after patroling. Test charge taken and line stood O.K


GETCO Y 26.07.08 5:05 26.07.08 5:40 Over voltage stage II trip at

SSP end.

3.17 400kV Koradi 400kV Koradi-Sarni

PowerGrid Y 30.07.08 6:52 30.07.08 6:52 A/R successful at both end

on R-N fault


400kV V'chal-Jabalpur Ckt.III

PowerGrid Y 30.07.08 11:43 30.07.08 19:17

A/T from both ends on B-E fault. A/R unsuccessful due to failure of B ph V outer string at Loc.No.1000.

3.19 400kV Raipur 400kV Raipur-Bhatapara

PowerGrid Y 03.08.08 0:16 03.08.08 0:33 Line tripped on O/V

3.20 400kV Satna 400kV Satna-Bina Ckt.I

PowerGrid Y 03.08.08 17:51 03.08.08 18:33

Tripped at Satna end and A/T at Bina end, due to B-E fault. Main-I & II protn. Optd. Due to frequent Opn. Of Main II, A/R unsuccessful (F/L-35.4% from Satna end)

3.21 400kV Raipur

400kV Raipur-Bhadrawati 1

PowerGrid Y 04.08.08 5:44 04.08.08 5:44

A/R successful at both ends on B-N fault. (F/L 10km from Bhadrawati)

3.22 400kV Chandrapur

400kV C'pur-Parli Ckt. 3

MSETCL Y 04.08.08 9:40 04.08.08 11:21

Line tripped on Y-N fault due to snapping of earth conductor between Loc.No.320 & 321


400kV V'chal-Korba 1

PowerGrid Y 04.08.08 12:51 04.08.08 14:40

Line tripped due to operation of NGR PRV at Korba end. Line taken into service without shunt reactor as per WRLDC instruction.

3.24 400kV Nagda 400kV Nagda-Dehgam II

MPPTCL Y 04.08.08 23:27 04.08.08 9:04 ???

3.25 400kV Raipur 400kV Raipur-Bhatapara

PowerGrid Y 05.08.08 6:06 05.08.08 14:32 Line tripped on Y ph O/V

stage-1 at Raipur end.


3.26 220kV KAPS 220kV KAPS-Vapi-1

NPCIL Y 06.08.08 19:30 08.08.08 17:30

Line tripped on pole discrepancy protection while taking outage for maintenance. The trip lever assembly and trip lever latch in trip control valve was faulty replaced the same.



PowerGrid Y 06.08.08 22:59 06.08.08 23:23

A/T from both ends on R-E fault (F/L 82.5% from Jabalpur)



PowerGrid Y 07.08.08 14:14 07.08.08 16:24

A/R from Jabalpur end only on transient Y-E fault(F/L 72.6% from V'chal). A/R was N/A mode at V'chal end. Thereafter line immidiately tripped on receipt pf Direct trip from V'chal end due to O/V at V'chal end.

3.29 220kV Korba

220kV Korba-Budhipadar 3

PowerGrid Y 07.08.08 17:00 07.08.08 18:12 Line tripped due to opn. Of

B/B protn. At Budhipadar.

3.30 400kV Raipur


PowerGrid Y 11.08.08 16:15 11.08.08 17:09 Line tripped due to operation

of Teed protn. At Raipur S/S

3.31 400kV Dehgam

400/220kV ICT-I

PowerGrid Y 15.08.08 7:52 16.08.08 14:14 400/220kV ICT-I, tripped on

T/F diff, O/C & E/F.

3.32 400kV Kolhapur

400kV Kolhapur-Mapusa 1

PowerGrid Y 21.08.08 13:15 21.08.08 13:46 Line tripped on DC earth

leakage at Kolhapur end.

3.33 400kV Raipur


PowerGrid Y 22.08.08 8:51 22.08.08 9:33

Line tripped due to maloperation of reactor back up protection relay at Raipur end.

3.34 220kV Korba

220kV Korba-Budhipadar 3

PowerGrid Y 22.08.08 13:25 22.08.08 14:24 Line tripped on R-E fault. (F/L

1.85km from Korba)

3.35 400kV Gwalior

400kV Gwalior -Agra

PowerGrid Y 23.08.08 3:31 23.08.08 4:04

400kV Main and Tie CB at Gwalior end tripped, due to operation of M-II relay and line remain charged from Agra end. Line charged from Gwalior end at 03:48hrs however line tripped from Agra end only. Relay might have mal operated

3.36 220kV KAPS 220kV KAPS-Vapi-2

NPCIL Y 24.08.08 12:12 24.08.08 13:40 Line tripped on DPS Zone-1

Phase C , carrier aided trip.

3.37 400kV Sipat 400kV Sipat-Patadhi

PowerGrid Y 25.08.08 11:40 25.08.08 12:02 Line tripped at Patadhi end

due to relay maloperation.


3.38 400 KV Chorania

400 KV Chorania-Asoj


Asoj end.

3.39 400kV Satna 400kV Satna-Bina Ckt.II

PowerGrid Y 25.08.08 13:58 25.08.08 14:55

A/R successful from both ends at 13:58hrs on B-E fault, however due to persisting B-E fault (98.4km from Bina end) generated 3ph trip. Patrolling report awaited.




Asoj end.

3.41 400 KV Asoj 400 KV Asoj-Amreli

GETCO Y 25.08.08 19:41 25.08.08 19:50 Transient tripping.



GETCO Y 25.08.08 23:34 25.08.08 23:43 A/R lockout at both end.

T/T



PowerGrid Y 26.08.08 4:10 26.08.08 5:32

A/R from Jabalpur end only on transient R-E fault (F/L 388kms from V'chal). A/T from V'chal end Line was on transfer breaker at V'chal and CB air pressure was low.

3.44 400kV Koradi 400kV Koradi-Satpura

PowerGrid Y 26.08.08 11:55 26.08.08 11:55 A/R successful on R-N fault

(F/L 10.9% from Koradi)


400kV Korba-V'cha 2

PowerGrid Y 30.08.08 10:38 30.08.08 11:07 Line tripped on Bph fault.(F/L

319.2km from Korba)


400kV V'chal-Satna Ckt.III

PowerGrid Y 01.09.08 18:49 ??? ???

A/R successful from both ends at 18:49hrs, however after 3sec DT recd. From V'chal end and line tripped again.(94.6% from Satna end) Jumper broken and fell on B ph line isolator.

3.47 400kV Raipur


PowerGrid Y 02.09.08 10:01 02.09.08 10:31 Line tripped on Ph-Ph fault

(F/L 149km from Raipur)

3.48 400kV Khandwa

400kV Khandwa-Dhule Ckt.I

PowerGrid Y 03.09.08 11:42 03.09.08 11:58 Line tripped due to persisting

B-E fault


PowerGrid Y 03.09.08 13:26 03.09.08 13:45

A/R successful from both ends at 13:26hrs on B-E fault, however due to persisting B-E fault (56.1% from Satna end) generated 3ph trip. Patrolling report awaited.

3.50 400kV Tarapur

400kV Tarapur -Padghe 2

PowerGrid Y 03.09.08 16:42 03.09.08 18:02 Line tripped on R-E fault (F/L

16.4km from Padghe)


3.51 400kV Tarapur


PowerGrid Y 04.09.08 15:26 04.09.08 16:14 Line tripped on R-E fault (F/L

40.5km from Tarapur)


PowerGrid Y 05.09.08 11:03 05.09.08 11:21

A/R successful from both ends at 11:03hrs on B-E fault, however due to persisting B-E fault (56.7% from Satna end) generated 3ph trip. Patrolling report awaited.


PowerGrid Y 05.09.08 13:11 05.09.08 13:36

A/R successful from both ends at 13:11hrs on B-E fault, however due to persisting B-E fault (57.3% from Satna end)generated 3ph trip. Patrolling report awaited.

3.54 400V Raigarh 400V Raigarh-Rourkela 1

PowerGrid Y 06.09.08 16:07 06.09.08 16:37 Line tripped on Y-E fault. (F/L

11.7km from Rourkela)

3.55 400kV Bina 400kV Bina-Nagda Ckt.II

PowerGrid Y 07.09.08 13:37 07.09.08 14:22

A/R successful at 13:37hrs on B-E fault, but again tripped due to persisting B-E fault at 119.8km from Bina.


PowerGrid Y 07.09.08 18:58 07.09.08 18:58

A/R successful at both ends on Y-N fault (F/L 166.5km from Raigarh)

3.57 4000kV Korba 400kV Korba-Korba(W)

PowerGrid Y 09.09.08 11:40 09.09.08 19:55

Line tripped due to snapping of Y phase conductor on Bus bar at Korba(W) CSEB bay, due to hot spot.



PowerGrid Y 09.09.08 15:57 ??? ???

A/T at both ends on R-ph to E/F. Line test charged at 16:14hrs but again A/T from both ends. R-ph V-string fail at Loc.No.165

3.59 400kV Tarapur


PowerGrid Y 09.09.08 16:51 09.09.08 18:02 Line tripped on Y-N fault. (F/L

74.9km from Tarapur)

3.60 765kV Sipat 765kV Sipat-Seoni-1

PowerGrid Y 09.09.08 18:59 09.09.08 21:10 Line tripped due to DT recd.

At Seoni.


GETCO 09.09.08 23:15 09.09.08 23:40 Transient tripping.

3.62 400kV Itarsi 400kV Itarsi-Indore Ckt.I

PowerGrid Y 11.09.08 11:46 11.09.08 12:23

A/T from Indore end, due to direct trip channel-2 send command wire at B-pole of tie CB in switchyard earth lekage.

3.63 400kV Raipur 400kV Raipur-Sipat 2

PowerGrid Y 12.09.08 11:29 12.09.08 11:55

Line tripped due to wiring mistake while working in Tamnar-2 main CB relay panel at raipur S/S



PowerGrid Y 12.09.08 13:34 12.09.08 14:02 Line tripped on Y-N fault at

45.53km from Rourkela

3.65 400kV Indore 400kV Indore-Asoj Ckt.II

PowerGrid Y 12.09.08 23:35 Bus Bar protn. Optd. At Asoj

end.


GETCO Y 14.09.08 12:33 14.09.08 14:20 Over -voltage stage II at 400

KV SSP end 435 KV.

3.67 4000kV Korba 4000kV Korba-Bhatapara

PowerGrid Y 17.09.08 12:08 17.09.08 13:40 Line tripped on O/V stage 1

at Korba

3.68 4000kV Korba 400kV Korba-V'cha 2

PowerGrid Y 20.09.08 11:24 20.09.08 14:05

Line tripped due to relay maloperation at V'chal(NTPC)

3.69 4000kV Korba (E)

4000kV Korba(E)-Budhipadar 3

PowerGrid Y 20.09.08 13:45 20.09.08 16:20 Line tripped due to

overloading

3.70 400 KV Asoj 400 KV Asoj-Ukai

GETCO Y 20.09.08 21:37 20.09.08 22:47

Bus bar protection operated at Asoj due to D.C control cable found faulty .

3.71 400 KV Asoj 400 KV Asoj-Wanakbori

GETCO Y 20.09.08 21:37 20.09.08 23:07

Bus bar protection operated at Asoj due to D.C control cable found faulty .

3.72 400kV Satna

400kV V'chal-Satna Ckt.III

PowerGrid Y 21.09.08 11:47 21.09.08 15:26

A/R at Satna end at 11:47hrs & after 5.87sec DT recd from V'chal end. Transient Y-ph-Earth fault.

3.73 4000kV Korba (E)

4000kV Korba(E)-Budhipadar 3

PowerGrid Y 22.09.08 14:07 22.09.08 15:50 Line tripped on Y-N fault at

99km from Korba


GETCO Y 28.09.08 6:03 28.09.08 6:36 Over -voltage stage II at 400

KV SSP end 433 KV.

3.75 400kV Bhilai 400kV Bhilai-Seoni CSEB 28.09.08 12:24 28.09.08 13:48 Line tripped on DPS Main-I

&II. A/R Lockout.

3.76 400kV Bhilai 400kV Bhilai-Seoni CSEB 28.09.08 12:24 28.09.08 13:48 Line tripped on DPS Main-I

&II. A/R Lockout.


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. It was once again stressed upon constituents that this recommendation is to be implemented expediously, and report compliance of the decisions of previous meetings.


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 schemes is stored in either of the relay.

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

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

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


generation of DR data.

delay of 1 sec can be given for triggering DRs.

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.

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 by Nov.08

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 by Dec.08. MPPTCL informed that this facility has been included in ERPC (Enterprising Resource Planning Scheme), which is under tendering process.

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 MSETCL has


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.

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

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.

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

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.


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.

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.

baart sarkar government of india kond`iya ivavut p ... · agenda of 103rd wrpc pcm 2.02: system...

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