LIST - wrpc · The list of participants is placed at Annexure -1. ... (11)220KV J’buva-1...

LIST 1) Chief Engineer (LD), MSETCL, Kalwa.Fax-27601769/65 2) Chief Engr. (Trans O&M), MSETCL, Bandra. Fax No. 022 26598587. 3) S.E. (T&C), MSETCL, Aurangabad Fax-0240-2234220 /2346290 4) S.E (T&C), MSETCL, Pune. Fax-9520-2617532/2612342 5) S.E. (T&C), MSETCL, Nagpur. Fax-95712-2234220 6) S.E.(T&C), MSETCL, Nasik Road Fax-0253-2462422 7) S.E.(T&C), MSETCL, Vashi Fax--022-27662055 8) S.E.(Gen.Tstg), MSPGCL,Eklahre, Nasik Fax-95253-2810496/2810499 9) S.E. (Task Force), MSPGCL, Nagpur Fax- 0712-2591717. 10) Chief Engineer (Gen), GSECL, H.O. Baroda. Fax-0265-5512129/2344537 11) Addl. C.E.(Testing), GETCO, Baroda. Fax-0265-2351218 12) Chief Engineer(LD), MPPTCL, Jabalpur. Fax-0761- 2664343 /2282632. 13) E.D. (T&C),MPPTCL, Jabalpur. Fax-0761-2661696 14) Addl.C.E., MPPGCL, Jabalpur Fax- 0761-2660063/2665805 15) E.E. (SLDC), MPPTCL, Indore Fax-0731-2874515 16) Chief Engineer (LD), CSPTCL, Bhilai. Fax-0788-2282632/0788-383633 17) C.E. (T&C), CSEB, Raipur.Fax-0771-4066988/07759-226227 18) EE (T) , CSPGCL- Fax.No. 07789-226227 19) S.E.(T&C), CSPTCL, Bhilai. Fax.No.- 20) S.E.(T&C), CSPTCL, Raipur. Fax No.0771-4066988. 21) E.E.(T&C), CSPTCL, Bhilai. Fax No. -0788 2281561 22) EE, Division VIII(MRT),Elect. Dept; Goa Fax 0832-2735124. 23) Supdt.Engr., Electricity Dept., DNH, Silvasa. Fax : 0260-2642338 24) Executive Engr., Electricity Dept. DD. Fax : 0260-2250889 25) D.G.M.(O.S. ),N.T.P.C., Mumbai, Fax- 28216692 26) D.G.M.(EM), KSTPS,NTPC,KorbaFax 07759-233088/ 232440 27) DGM (EMD), VSTPS, NTPC, Vindhyachal Fax-07805-247713 28) DGM (EM-I),NTPC, SIPAT Fax-07752-246506/246691. 29) AGM(O&M), KGPP,Adityanagar, Surat Fax 0261-2861428/2861433 30) Sr.Supdt. (EM),Gandhar, NTPC Fax-02642-87402 / 87450 31) DGM (O.S.), WRLDC, Mumbai Fax-28235434 32) DGM, WRTS-I POWERGRID,Nagpur.Fax-95712-641366/2641496 33) Addl General Manager, WRTS-II,POWERGRID,Baroda Fax-0265-2480952 34) SME (E), TAPS-3&4,Tarapur Fax 02525-282001/282073 35) Maintenance Superintendant,TAPS –1 & 2,Tarapur.Fax- 02525-282121 36) SME(E), NPCIL ,Kakrapara Fax 02626-234266 37) GM(Maint.). T.Power., Ahmedabad.Fax-079-27506679 38) AGM (ET&A),TPC, Trombay. Fax –022-66687088 39) Dy.Gen. Manager,Dahanu TPS Fax- 952528-222576 40) Vice President, Reliance Energy, Mumbai Fax-30094488 41) GM (Electrical), JPL, Raigarh. Fax.No.7767-281995,281993. 42) Director (G M Division), CEA, New Delhi. Fax.No.011-26109750 43) AGM(OS), NSPCL, New Delhi . Fax.No.011 26717363/26717366 44) GM, KSK Mahanadi Power Co Ltd., Hyderabad- Fax.No.04023559930 45) Director (Tech & Projects), JSW Energy( Ratnagiri) Ltd., Fax.No. 022 67848393 46) GM, RGPPL,Anjanwel,Guhagar,Ratnagiri. Fax.No. 02359 241071

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MINUTES OF THE 114th PROTECTION COMMITTEE MEETING OF WRPC

HELD ON 11/12.06.2012 AT WRPC OFFICE, MUMBAI

The 114th Protection Committee Meeting of WRPC was held on 11/12.06.2012 at WRPC

Mumbai. The list of participants is placed at Annexure -1.

Shri S. D. Taksande, Member Secretary (I/C), WRPC, welcomed all the members and the

participants of the 114th Protection sub-Committee Meeting. He stated that occurrences

during September 2011 to February 2012 are mainly included in this agenda. However, due

to non-availability of relevant data some of the major occurrences could not be discussed

during last meeting the same have been included in this agenda. As regards to the PSDF fund,

he further intimated that staff paper has been circulated by CERC amongst all the constituents

for comments. In the staff paper it is proposed that the PSDF fund accumulated would be

reversed to respective Region. Hence the item of current differential protection on short lines

using OPGW will be discussed here separately without linking it with PSDF.

He further intimated that Shri Jawalikar, SE(Protection), MSETCL is retiring on 30th June

2012. He has contributed immensely in the protection forum since 2005 and his guidance,

suggestions, knowledge have enriched the forum and helped the committee to take proper

decisions during past.

Shri Jawalikar stated that it is probably his last meeting and hoped that his successor would

also contribute similarly in future.

Member Secretary (I/C) then requested Shri M. M. Dhakate, SE(Protection), WRPC to take

the agenda items for discussion in seriatim.

SE(Protection), WRPC welcomed all participants attending 114th meeting of Protection sub-

Committee. He stated that additional agenda for disturbances in Gujarat State have been

circulated to all. Also, during last meeting, Reliance Infra was requested to make a

presentation on islanding scheme at Mumbai and requested Reliance Infra representative to

present the same.

Reliance Infra representative made a presentation on Mumbai islanding scheme the details of

which are included in Item No. 6.3.

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ITEM NO.1: CONFIRMATION OF MINUTES OF 113TH PROTECTION

COMMITTEE MEETING.

SE(Protection), WRPC stated that the minutes of 113th PCM, held on 6th March 2012 at

WRPC Mumbai, were circulated vide WRPC letter No. Prot./113 PCM/2012/WRPC-2815

dated 26th March 2012 and no comments have been received on the minutes.

Committee confirmed the minutes of 113th Protection sub-Committee without any

modification.

ITEM NO.2: SYSTEM DISTURBANCES

2.1: System disturbances in CSPTCL/CSPGCL system.

2.1 (i) System disturbance at 400 kV Korba system in CSPTCL system on 19-04-11.

CSPGCL representative explained the disturbance as below:

On 19.04.2011 at 19:53hrs., 220kV Korba(W)-Kotmikala-I line tripped from both ends on

operation of Main-I at Korba(W) end, at 19:54hrs 400/220kV Korba(W) ICT tripped on PRV

with several alarms like oil temperature, Buccholz etc. It was heavy rains that day and the

moisture entry into control panel of ICT have caused this mal-operation. At around 20:00 hrs,

220kV Korba(W)-Kotmikala-I was synchronized. At around 20:12 220kV Korba(E)-

Korba(W)-I and III lines at K(E) end on R-E zone-1 fault and Korba(W)-Kormikala lines 1

& 2 tripped from Kotmikala end tripped. 220 kV KW-Mopka feeder tripped on overload

resulting into islanding condition at Korba(W) s/s resulting into tripping of unit 1 &2 at

Korba(E) on over speed protection.

At the same time, at Korba (E) Raigarh, Budhipadar 2 & 3, Mopka(Siltara), BALCO 1&2,

DSPM feeder tripped on Directional overcurrent at remote end resulting into islanding

conditions at Korba (E) which resulted into tripping of all units at Korba(E) on overspeed.

At DSPM TPS 220 kV Banari and Suhela feeders tripped on zone-I protection at both ends.

All these conditions cumulative resulting into heavy system disturbance and sudden load-

throw-off condition created unstable situation in the grid and both 250 MW units at DSPM

tripped.

It was concluded by committee that due to heavy thunder storm, lightening, heavy rains

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DSPM to Banari and Suhela feeders tripped on transients faults resulting into loads of both

the 250 MW generators flowing towards Korba(E) and Korba(W) feeders which were

already load starved resulting into large power swing in the remaining system and tripping of

all the units.

MS intimated that a Special protection scheme was already proposed in the past to arrest the

cascade tripping due overloading of elements in the area around Korba(E), Korba(W) and

DSPM system, due to tripping of 220kV lines. WRLDC intimated that the earlier proposed

scheme would not be helpful now, since new lines and generators have been added in the

area. MS suggested meanwhile O/C settings could be reviewed.

CSPGCL representative informed that the existing over current settings adopted for the lines

are 100%. Committee recommended that in the absence of SPS, the over current setting

of the lines in the area can be raised to 150% so that sufficient time margin would be

available to take corrective actions in the event of loss of line in the area thereby

avoiding overloading the other lines by cutting-off the load or backing down the

generation. Committee further suggested that WRLDC would device SPS in

consultation with CSPGCL/CSPTCL on urgent basis.

2.2: System disturbances in GETCO/GSECL system.

2.2(i) Occurrence at 220 KV Karamsad s/s on 26.10.2011 at 15.40Hrs

ACE(Trans), GETCO explained the disturbance as below :

On 26/10/11 at 15:40Hrs monkey was electrocuted at B ph of Main BUS-A (Pipe Bus) during

climbing on gantry structure nearby Ranasan 1 feeder Bay resulting into 220 KV Bus A fault

at 220kV Karamsad S/S. Bus B saved due to tripping of Bus coupler. ABB make RADSS

type Bus bar protection scheme did not operated, hence the feeders tripped from opposite

end.

Sequence of occurrence: , • Asoj 1&2 tripped on Reverse zone at Karamsad end. • GPEC-1 tripped on DT Rec. at Karamsad end , • Feeders connected to BUS-A (Jambuva-1,Salejada,Ranasan-2, Kasor-1)

tripped from opposite end • 100 MVA Transformer-1 Tripped from LV only on E/F. • Bus coupler tripped on Over current. • Feeders connected to Bus-B(Jambuva-2, Vartej, Kasor 3) tripped from opposite

end

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Relay indication:

Feeder (1)220KV B/C (2)220KV Kasor-1 (3)220KV Kasor-2 (4)220KV Kasor-3 (5)220KV R’nasan-1 (6)220KV R’nasan-2 (7)220KV Asoj-1 (8)220KV Asoj-2 (9)220KV GPEC-1 (10)220KV GPEC-2 (11)220KV J’buva-1 (12)220KV J’buva-2 (13)220KV VERTEJ (14)220KV Salejda (15)220/132KV Tr-1HV (16)220/132KV Tr-2HV (17)220/132KV Tr-2A HV (18)132KV ODE

This end relay indication O/C Trip No Trip No Trip No Trip No Trip Z4,Bph to E,-956.8M Z4,Bph to E,-1.298KM Z1,Bph to E, DT Rec. No Trip No Trip No Trip. No Trip No Trip No Trip No Trip No Trip No Trip

Opposite end relay indication Z1,Z2,Z3,Rph to E,CR Z2,Bph to E No Trip Z2,Bph to E,64.74KM No Trip No Trip Z2,Z3,Bph to E,118.5KM No Trip Bph to E, Bph to E, Z1,Bph to E,131.7KM Z1,Bph toE,56.97KM LV side Trip ----- ----- E/F Trip

Committee observed that tripping of lines from opposite end in Zone 2, from local end

on reverse Zone & 220kV B/C tripping on O/C trip indicates that the fault was of

permanent nature and the BB protection should have operated. Committee

recommended that through testing of BB protection be carried out including CTs, CT

wiring from Bay to Panel, test for saturation of CTs and leakage in CT wirings.

2.2(ii) Bus bar operation at 400 KV Chorania S/s on 30-01-12

ACE(Trans), GETCO explained the occrence as below :

Bus bar operation took place on dated 30/1/12 at 8.30 hrs at 400 kV Chorania s/s. 400 KV

Chorania –Asoj line no.1 was under shut down on 27.01.12 for PM work at Chorania end.

The earth switch alignment work completed on same day and line kept under H.V. off

condition. During charging of Chorania –Asoj line no.1 on dated 30.01.12 at 8.30 hrs, line

tripped on bus bar protection and simultaneously all feeders connected to Bus-II tripped on

bus bar protection.

GETCO reprentative further informed that the earthing on B-Ph. of 400 KV Asoj –Chorania

line no.1 between CT & breaker was not removed after completion of work.

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400 KV Chorania-Vadavi line no.2 which was commissioned around 15 days before,

tripped(mal operation) on bus bar protection at Chorania end although Auto reclose scheme

operated at Vadavi end. It was due to wrong configuration and PLCC wiring, thus direct

command was not received at Vadavi end for Auto reclose lock out. PGCIL have corrected

and checked logic of the scheme. Scheme is kept under observation.

Committee observed that the operation of busbar protection was in order. However

before taking into service the staff would have ensured that all the earthings were

removed on the shutdown line thereby avoiding the occurrence.

2.2(iii) Occurrence at 220kV Navsari s/s on 26.02.12

ACE(Trans), GETCO explained the occurence as below :

GETCO have intimated that at 11.55 hrs, all 220kV Breakers tripped from far end except 220

kV Navsari-Vav line. Due to reflected fault of 220kV Navsari- Talangpore line Bkr not

tripped so all 220kV lines tripped from far end except 220kV Vav line. During line patrolling

loc no 528(S)- 529(S) sugar cane burnt found & conductor found damage, same has been

attended on 27.02.12 at 14.00hrs. At Chorania S/S it is single bus configuration without

sectionaliser and busbar protection scheme.

Committee recommended that in the absense of busbar protection scheme, remote end

zone-2 timings can be reduced to 200 ms. Further wherever available the reverse zone

setting of the lines be adopted such that it coveres the busbar zone and trips the line

instantaneously.

2.2(iv) Occurrence at 220kV Ukai TPS on 22.12.11

GSECL representative explained the occurrence as below : First occurrence :For - 500 MW Unit No. 6 power evacuation is at 400 KV, as there was

no space available for new Panel in old Control Room so all the old and new panels were

shifted to new 400 KV Control room. On 22.12.2011 at UTPS

220 KVBUS-I 220 KVBUS-II

315 MVA ICT feeder GT#1,2,3,4 & 5. 220 KV Th.-Hy. Tie #2 line ST# 1,2 &3. 220 KV Achhalia line# 1,2 &3 220 KV Mota line#1 & 2

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At 14.02 Hrs 315 MVA ICT charged from 220 KV side on bus - I successfully. After

successfully charging of ICT 220 KV Bus coupler breaker was made “ON”. As everything

stood OK, Next procedure for normalising of bay’s on both the buses was taken on hand and

started with shifting of Mota line-I from Bus-II to Bus-I. Bus-I isolator of Mota-I was closed

to parrallel with Bus-II . But while opening of Bus-II isolator, heavy spark observed on B-ph

jumper (29A) of Bus Coupler bay and one conductor from twin conductor snapped and

earthed causing Bus A Busbar protection operation and following trippings occurred.

1. 220 KV Hydro Tie line-II 2. 220 KV Mota I line-I 3. 220 KV ICT 4. 220 KV Bus Coupler 5. 220 KV Achhalia line-II All trippings except Achhalia Line are correct. Achhalia line tripping should not have

happened, on investigation backup overcurrent CT polarity was found reverse in distance

protection core. This mistake has happened while replacing of 220KV CT previously hence

same has been corrected.

Second occurrence : Due to above tripping Mota Line-I and Hydro tie line-II was to be

shifted back to Bus-II So Both Bus isolator of Bus coupler were opened. Mota line-I. Bus-I

isolator opened and then Bus-II isolator closed and CB was made ON successfully. While

changing over of Hydro tie line-II from Bus-I to Bus-II, operational staff Closed Bus-II

isolator prior to opening of Bus-I isolator. This resulted into extended Bus-fault as Bus-I was

in unhealthy condition And all GT’s were tripped and all lines tripped from opposite end

hence zero power occurred at Switchyard, Ukai TPS. Simultaneously, Bus-II B-ph jumper

of Hydro Tie line-II conductor snapped and earthed at 14:42 Hrs.

Analysis :1.Normal Load on the Mota line-I is 500 Amp. to 600 Amp., this has passed

through Bus coupler CB and resulting into snapping of one conductor from twin conductor

causing Bus-I Bus bar differential protection operated and resulted into tripping of line and

Transformer (ICT) connected with Bus-I and Achhalia line-II on Bus-II.

2. Because of wrong operation of isolator i.e. closing of Bus-II isolator prior to opening of

Bus-I isolator resulting in to zero power at Ukai TPS.

On query, GSECL representative intimated that earlier scheme of CAG relay is old but the

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CT was changed. Just two months before this occurrence the Achalia feeder was tripped on

backup overcurrent and the matter is under investigation.

Committee observed that the incidence occurred due to human error and trippings are in

order. Committee recommended that all bolted clamps of isolators should be changed to

boltless clamps.

2.3: System disturbances in MPPTCL/MPPGCL system.

2.3(i) Occurrence at 132 KV S/S AT Gandhisagar on 24.08.2011 at 19:15 Hrs.

The incidence was discussed in the last protection sub-Committee meeting wherein it was

noted that :

On 24.08.2011 at 19:15 Hrs, due to heavy rains and lightening at Gandhisagar following

tripping occurred.

1. 132 kV Garoth-Gandhisagar line tripped at Garoth end and handtripped at Gandhi sagar end.

2. 132 kV Suwasra-Gandhisagar line tripped from Gandhisagar end in zone-I and from Suwasra end in zone-II.

3. 132 kV Manasa-Gandhisagar line tripped from Gandhisagar end 4. 132 kV Gandhisagar-RPS-II hand tripped after Gandhisagar bus got dead

It was intimated by MPPTCL that 132 KV Garoth line breaker at Gandhisagar end did not

trip due to some problem in protection relay setting which caused other outgoing feeders also

sensed the fault and tripped. Also, 132 kV Gandhisagar-RPS-II breaker did not trip at

Gandhisagar end. Detailed investigation report from MPPGCL is awaited.

Committee during last meeting had observed that the tripping of 132kV Suwasra-

Gandhisagar at Suwasra end in Z-II is undesired and should have tripped in Z-1. Also,

tripping of 132kV Garoth-Gandhisagar from Garoth end is undesirable, since the fault was

isolated due to tripping of 132kV Suwasra-Gandhisagar line. Also the DPS of 132kV

Gandhisagar-Manasa line at Gandhisagar end sensed the fault on 132kV Suwasra-

Gandhisagar line in reverse direction which is undesirable.

Committee observed that the settings of DPS at 132kV Gandhisagar end and remote end may

be checked/reviewed. Also testing of the DPS be carried out to check the above mal-

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operations.

MPPGCL vide letter No. 07-02/Protec./480 dated 2.03.2012 (enclosed at Annexure-2.3(i))

have intimated that :

1. Testing of Distance Protection Relays (DPR) of all 132 kV outgoing feeders of

Gandhisagar was carried out on 14.09.2011 and were found functioning satisfactorily except

some sluggishness in indication flag of DPR of 132 kV Gandhisagar-Suwasra and

Gandhisagar-RPs feeder No.1 which have been rectified.

2. General servicing and maintenance of 132 kV breaker of 132 kV Garoth Ckt. at

Gandhisagar has been carried out and ON/OFF operation has been checked.

3. DPR relays of 132 kV Gandhisagar-Garoth at Gandhisagar was found satisfactorily,

however to ensure more reliable operation of protection system and security of 132 kV grid,

old conventional EE make relay has been replaced by new numerical relay and tested

satisfactorily on 16.09.2011.

Committee noted and appreciated the submission of action taken and reporting by

MPPTCL.

2.3(ii) Occurrence at 400 kV Nagda S/s on 21.12.2011

MPPTCL representative explained the occurrence as below:

On dt. 21.12.11 at 05:05 hrs all three ICTs tripped due to operation of 400 KV Bus Bar

Protection ( ABB make, Type REB 670) for 400 KV main bus I, however, 315 MVA

Transformer III was remain charged through Tie CB and tripped on Over Load Protection

after 5 seconds of main event.

Prior to this, about 645 MW load was shared by all ICTs and after ICT- I & II, entire load

was shifted to ICT III and 220 KV lines connected to 400 KV S/s Indore, and to save further

trippings, load dropping scheme stage-I also operated and provided a load relief of about 100

MW by 220 KV Kota feeder from 220 KV S/s Badod.

On investigating the occurrences, it was found that though trippings occurred through 400

KV Bus Bar scheme, but No event or disturbance recorded in the bus bar scheme REB-670,

however its trip bus is common for Bus Bar Protection as well as for LBB protection of 400

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KV elements. But on checking of events and LBB schemes of all the 400 KV elements

contributing the 400 KV Main Bus I, No event or signal detected regarding LBB operation or

any fault condition. Oscillography recorded by T-60 Differential Relay of ICT III, also

confirms that, the currents before and after this event were normal. There were no fault

current or fault situation detected before and after this event. Therefore, it is suspected that

the ABB make type REB 670 bus bar protection scheme has mal-operated and caused this

trippings. Scheme thoroughly checked & found normal. Bus bar protection scheme is just

three month old to occurrence date.

Committee opined that busbar scheme operated due to malfunction or unknown reasons and

suggested that matter may be referred to original manufacturers. Committee recommended to

modify load dropping scheme on the three ICTs.

2.3(iii) Occurrence at 400 kV Indore S/s on 22.02.2012


On dt 22-02-12 at 10:39 Hrs, tripping occurred on 220 KV South Zone I feeder at 400 KV

Substation Indore. This feeder tripped from 220 KV South Zone substation Indore on “C”Ph

Zone I indication at South Zone substation, but did not tripped from 400KV Substation

Indore. Simultaneously 220KV Bus Bar protection for Bus II also operated & all the feeders

connected on Bus II were tripped. After yard inspection & ensuring that there is no fault on

220 KV Bus, same was charged from 220 KV Barwaha Substation at 11:45 Hrs through 220

KV Barwaha II feeder & there after system normalized by charging the feeders in sequence.

On analysis of tripping data from 220 KV Bus Bar Protection scheme of GE make type B90,

it was found that for busbar protection, fault on 220 KV South Zone feeder would be through

fault but the bus bar protection operated. Data reveals that the difference of current to the

tune of 10000Amps recorded by bus bar protection resulting into operation of bus bar relay.

Current waveform of south Zone I feeder was also found deformed. It was suspected that

tripping occurred due to some discrepancy in220KV CT (SCT make) which has caused

unbalance of current.

Remedial Action:- Detailed inspection of 220KV SCT make CT carried out & an additional

interposing CT found connected in primary of the CT, which gives erratic results on higher

current & causing unwanted tripping. This CT (2008 lot) replaced by available spare CT and

feeder normalized. Complete lot of 2008 SCT make CTs were changed.

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Committee discussed the occurrence and noted that in RADSS busbar scheme do not

operate due to CT saturation. But here in B-90 GE make bus bar scheme operated due

to CT saturation. Committee recommended that an interposing CT should not be used

in busbar scheme.

2.3(iv) Occurrence at 220 kV Bhopal S/s on 31.01.2012


Routine shut down on 220 kV Bus-2 was availed on 31.01.2012 for attending Bus-2 IBM

jumpers in section 5 so that all 220 kV feeders and I/c 2 were shifted to Bus-I . In the

process of normalizing the S/D while tranformer I/C 2 was being shifted from Bus-I to Bus-

2, Main Zone A, Main zone C and check zone operated tripping all the 220 kV feeders and

transformer I/Cs. Busbar scheme is PBDCB of EE make.

Simulation of changeover of transformer 2 from Bus-1 to Bus-2 was carried out and on

investigation it was found that CT switching relay of Bus-2 did not operate which created

dissimilarity between Yard status and CT switching relay. The unbalance current in Main

Zone A, Main zone C was found to be 150 mA 160 mA. Spill current of 8.8 mA to 9.4 mA

was also observed in check zone. In two main and transfer scheme whenever a feeder on one

Bus is shifted to another bus, unbalance of current in Main zone A and C us inevitable and

depending on the magnitude of the unbalance current these zone may operate. The security

of bus bar scheme is ensured through the check zone where CT switching does not take place.

All the three zones are equipped with CT supervision relays which operate and short the CTs

if the spill current is more than set value (3.5 to 4 mA which is maximum setting). The

operation of CT supervision relay blocks the Main zone A & C while it bypass the check

zone.

In the above incidence Main zones operated during changeover and check zone was

bypassed due to operation of CT supervision relay. Defective CT switching relay has been

replaced and changeover scheme checked and operated successfully. MPPTCL has propesed

to replace the existing scheme by scheme based on numerical philosophy.

Committee discussed the occurrence and opined that there seems to be some problem in

logic of the scheme. Also spill current of 20 mA should be allowed to flow without any

operation. Committee advised to recheck the whole scheme.

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2.4: System disturbances in MSETCL/MSPGCL system.

2.4(i) Occurrence at 220 kV GTPS Uran on 7.06.2011 at 23.11 Hrs

MSETCL representative explained the occurrence as below:

On 7.06.2011 at 23.11 Hrs the 220 kV Bus bar Protection of Main bus-I Siemens make

operated due to failure (bursting) of Y-Pole of 220 kV CGL make SF6 breaker of Uran GT

U-5 which resulted into tripping of all equipments/feeders connected to Main Bus-I including

B/C at 220 kV Uran S/s. MSETCL representative intimated that the overcurrent setting for

B/C is 100 ms definite timedelay with 80 % current. MSETCL intimated that B/C tripped

on Y-E/F indications and the fault was cleared in 70 ms and fault current recorded is 14 KA.

The reverse zone of DPS of some of the 220 kV feeders also picked up and indicated the

clearance of fault in 70-80 ms. MSETCL further intimated that BB1 differential protection

and overall differential protection is found to be delayed resetted . GT U-5 continued to feed

the bus fault till generation came to zero, since GT U-5 protections did not operate since it

was through fault for GT U-5 protection.

MSETCL further intimated that GT U-8 tripped on TF differential/backup/PRV/REF

protection. GT U-5 was restored at 15:40 hrs on 7.06.11 through TBC and shifted on own

breaker after replacement of pole and carrying out all pre-commissioning test. GT U-8 kept

out for inspection.

Committee discussed the occurrence and recommended that overcurrent setting of B/C

should be definite time (not IDMT) with time setting less than the zone 2 timings(i.e.

100ms.)

2.4(ii) Multiple tripping of 400 KV lines at 400 kV JSWEL, Jaigad (Ratnagiri) sub-

station on 17.03.2011

JSWEL representative explained the disturbance as below :

Time Events 3:06 Line -3 (Jigad-Karad ckt-1) tripped on R-phase distance protection,

distance-10.34KM from Jaigad end. 3:08 Line-4 (Jaigad-Karad ckt-2) tripped on B-phase distance protection,

distance-1.69KM from Jaigad end. 3:28 Line-4(Jaigad-Karad ckt-2) charged. 3:35 Line-3(Jaigad-Karad ckt1) charged. 3:37 Line-2(Jaigad-New Koyna ckt-2) tripped on B-phase distance protection,

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distance-11.55KM from Jaigad end. 3:42 Line-4(Jaigad-Karad ckt-2) tripped on B-phase distance protection,

distance-1.8KM from Jaigad end. 3:46 Line-3 (Jaigad-Karad ckt-1) tripped on Y-phase distance protection,

distance-11KM from Jaigad end. 3:50 Line-3 (Jaigad-Karad ckt-1) charged. 3:58 Line-2(Jaigad-New Koyna ckt-2) charged. 4:02 Line-3(Jaigad-Karad ckt-1) tripped on R-phase distance protection,

distance-10.59 KM from Jaigad end. 4:03 Line-2(Jaigad-New Koyna ckt-2) tripped on Y-phase distance protection,

distance-16.49 KM from Jaigad end. 4:13 Line-1(Jaigad-New Koyna ckt-1) tripped on R-phase Distance protection;

distance 15.28 KM from Jaigad end. 4:13 All four units tripped due to AC failure(Black out) JSWEL representative explained the reasons for excessive tripping of JPTL Lines as below : Corona effect on the JPTL line is much higher than when compared with similar coastal areas. This is due to following reasons:-

• The relative humidity in Ratnagiri during this season some times reaches above 90% during night times.

• The transmission lines pass a long distance in vicinity of seawater which also causes deposition of salt laden dust over the insulator.

• Further to this it was found that the excessive corona in transmission lines in Ratnagiri region is due to “Malter Effect”that whenever oxides of aluminum (AL2O3) Zinc, Magnesium etc. are subjected to electrical stress they release secondary electrons. The soil is Laterite which contains high proportion of Al2O3 which actually escalate the corona process.

• The laterite laden dust over insulators of 400 kV insulators when subjected to foggy weather results into a deadly combination resulting into excessive line tripping’s of 400 kV JPTL lines .This problem is further aggravated due to higher voltage prevailing in 400 kV network .(the present voltage is around 420 kV during night time)

Following remedial measures to prevent Multiple Tripping were adopted by JSWEL

• Coldline washing – As per preventive maintenance schedule, Based on Night patrolling observations. Extensive coldline washing has been done as per patrolling observations.

• Application of Silicon Grease – This measure did not yield intended result. Heavy corona & Noise observed and insulator carbonized even after application of Silicon Grease. (Refer Photos)

• Insulator Replacement – Replacement of Antifog Porcelain Disc Insulators with Polymer Long Rods at identified critical Locations.

• Installation of creep Extenders over insulator is being studied.

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Insulator replacement works carried out by JSWEL • Antifog Porcelain Disc Insulator strings of 6 cut point towers ( majority near plant

area) of three circuits of both the transmission lines has been replaced with Polymer Long Rods.

• All porcelain pilot strings of one circuit of both transmission lines in the identified trouble area (Tower No 1 to 52) has been replaced with Polymer Long Rods.

• All porcelain suspension strings of one circuit of both transmission lines in the identified trouble area (Tower No 1 to 52) has been replaced with Polymer Long Rods.

System improvement in the long run • Behavior of the replaced insulator strings are to be observed for this season. • Based on the success rate of the replacement works other circuits can also be

protected. • Emerging trouble areas have been identified for future course of action.

Committee discussed the occurrence and constituents shared their experiences on line

tripping in coastal area due to salt /deposits on the insulators. Constituents informed

that even after replacing porcelain insulators with polymer insulators the problem of

insulators failure can only be minimised. However regular and frequent hot line

washing is the only effective way to prevent insulators failures.

2.4(iii) Bursting of station transformer No.4 lightening arrestor at Chandrapur STPS

on 29.08.2011

MAHAGENCO representative explained the occurrence as below :

On 29.08.2011 at 17:35 Hrs B phase lightening arrestor of station transformer No.4 was

suddenly burst due to ageing (1989 YoM) resulting into failure of station supply.

Annunciation for Bus-bar protection operation was observed on the panel but in fact there

was no operation of bus-bar protection. Units 5, 6 & 7 tripped on drum level low because of

failure of supply to MDBFP. Operation of 400 kV bus bar differential relay is not justified.

Station transformer -5 also tripped due to malfunction of LV REF protection relay.

MSETCL representative informed that there was no operation on BB protection.

However due to wiring problem the annunciation of BB protection operated, appeared

on the GCR annunciation window and there was no tripping on BB protection.

Committee observed that false annunciation on the GCR annunciation window might

have appeared due to loose control wirings and the same should be checked thoroughly.

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2.4(iv) Occurrence at Koradi TPS on 29.07.2011 and 26.09.2011

A. Occurrence of 220 kV busbar scheme at Koradi TPS on 29.07.2011

MSETCL representative explained the occurrence as below :

On 29.07.2011 at 16:28 Hrs 220 kV(2 Main + 1 Auxiliary bus) ABB make RADSS Bus bar

protection operated tripping 315 MVA ICT-III, Ambazari line, Khaparkheda line, station

transformer No.4 and Unit#6 at Koradi TPS tripped due to loss of auxiliaries. As the fault

was cleared locally by fast operation of Bus bar scheme, there were no trippings at remote

end. Also 400 KV & 220 KV grid remained stable.

The work of shifting of control of existing 220 KV bays to new 220 KV BCU SCADA was

under taken at 400 KV Sub-Station Koradi w.e.f. 28.06.2011. The work of shifting of

control of 4 line bays & TBC was completed by 25.07.2011 and the work of shifting of

control of 220 KV Bus coupler was in progress. The 220 KV Bus coupler bay was therefore

under outage w.e.f. 25.07.2011 and 29A & 29B isolators of the bus coupler bay were kept

OFF however one end of these isolators towards respective bus was live. The work of

alignment of auxiliary contacts of 29B isolator was undertaken on 29.07.2011 at @ 15:45

hrs by substation maintenance staff for which the section of the 220 KV bus coupler bay

between bus coupler breaker & 29B isolator was kept earthed with discharge rod.

However during the process of alignment of the auxiliary contact drum, the arms of the live

& earthed pole of the 29B isolator, which were earlier well apart, abruptly moved and came

close to each other in the arcing zone. Heavy arcing was noticed particularly between

contacts ‘B’ phase of isolator.

Committee discuseed the occurrence and recommended that the work could have been

better done by making entire 220 KV Bus 2 dead.

B. Occurrence of 400 kV busbar scheme at Koradi TPS on 26.09.2011


Outage was to be availed on 400 KV Bus2 at 400 KV S/S Koradi on date 26.09.2011 for

erection of Isolator for 400 KV Khaparkheda new circuit. For availing this outage, 400 KV

Bus2 was to be made FREE. There were total 5 bays that were connected to Bus2 and were

required to be shifted to Bus1 for this purpose. The process of shifting of Bus2 bays to Bus1

started by the operating staff of Koradi S/S w.e.f 00:00 hrs on date 26.09.11. By @05:45 hrs

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4 no of bays (Viz: Bhusaval, Bhilai, Sarni & ICT2) were successfully shifted from Bus2 to

Bus1 and thereafter, the process of shifting of last bay (i.e. GT6) was undertaken.

Following sequence of operations were already completed by @06:00 hrs: a. 29C isolator of GT6 bay was CLOSED. b. TBC breaker was CLOSED with its 29B & 29C isolators CLOSED (i.e. TBC was on

Bus2) c. Own breaker of GT6 bay was OPENED with its 29A isolator CLOSED while 29B

isolator OPEN. Transfer operation of GT6 bay form Bus-2 to Bus-1 was therefore half-way through with the status that the bay was on TBC with its own breaker OFF. Following sequence of operations were yet to be performed: a. CLOSING of own breaker of GT6 b. TRIPPING of TBC breaker c. oPENIG of 29C Isolator of GT6 bay d. Switching of NT switch of GT6 bay to ‘N’ (i.e. Normal) position.

At @06:00 hrs, the B pole of 29C PG isolator of the GT6 bay, which was carrying a load of

@164 MW, was INADVERTENTLY opened apparently due to some human error. Instantly

after partial opening of the main contact of the said PG isolator, heavy ARC occurred across

the PG isolator jaws and overhead line termination. This resulted into bus fault at 400 kV and

all the breakers connected to 400 KV bus-I tripped. The 220 KV bus at Koradi S/S remained

unaffected in-spite of tripping of both the ICTs at Koradi.

The arc fault across 29C PG isolator was being fed through Bus-2 via TBC breaker.

Busbar protection, however, did not operate selectively as the Bus-Interconnection of busbar

scheme was already persisting due to different isolator positions of GT6 & TBC attained

during the process of shifting. This bus interconnection of busbar scheme further caused Bus-

1 scheme to become Master. Under such situations, the Busbar scheme loses the selectivity

and permits to operate the busbar scheme in Zone1 irrespective of the section of the bus in

which the fault has occurred. Thus operation of the busbar scheme in Zone1 and subsequent

tripping of breakers connected to all busbar sections is IN ORDER.

For this bus fault of arcing nature, all the source 400 KV lines tripped at their respective end

on distance Zone2, B-N (Zone2 time delay: 300 ms) prior to the operation of busbar

protection. The ICT2 also tripped at local end on LV B/U O/C B phase (estimated time of

operation 350 ms) prior to busbar operation. The delay (400ms) in operation of the busbar

scheme is attributed to the fact that the built up of appreciable fault current for operation of

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busbar scheme for arcing faults of resistive nature is rather slow. However distance relays

remain unaffected as they operate on reactance measuring principle. Hence tripping of all

lines on distance Zone2 B-N for bus fault at Koradi is IN ORDER

Tripping of 400 KV Chandrapur – Khaparkheda line at Chandrapur S/S for bus fault at

Koradi is however undesirable. Zone2 reach setting of this line is very critical due to typical

line configuration (long line followed by very short line). The protected line is 150 KM while

Khaparkheda – Koradi line is just 6KM. Further the line configuration towards Khaparkheda

end is hybrid (i.e. AAAC & ACSR). Under such critical conditions over-reaching is possible.

As there is no scope for revision of reach setting of this line, the desired discrimination can be

achieved by revision of Zone2 time delay setting of the line at Chandrapur from existing 300

ms to 350 ms).

Remedial measures :

• Proper understanding of sequence of operations, proper coordination among the

operating staff and proper supervision by the concerned authority

• Mechanical and electrical Interlocks to avoid prohibit incorrect operations were

provided at the time of commissioning of the bay but found to be bypassed during

service of equipment. Proper interlocks could have averted the incidence

• Outages involving tedious operations for longer duration should preferably be availed

during day hours to avoid any fatigue for operating staff.

• Due to critical line configuration of 400 KV Chandrapur – Khaparkheda line the

Zone-2 time setting is now revised from 300 ms to 350 ms.

PGCIL representative intimated that 1.75 KA fault was fed from Bhilai and for this level of

fault busbar scheme should have been operated quickly.

Committee felt that tripping of the ICT2 from LV side on O/C B-phase before operation

of BB protection indicates that the fault was persisting in nature and was not arcing

fault. Committee discussed the occurrence and found that operation of the busbar

scheme BB RADSS is delayed and not justified and only TBC could have cleared the

fault and such non-clearance of such fault by TBC could be referred to ABB by

MSETCL. Committee further recommended that it shall be ensured that Electrical &

Mechanical interlocks are not removed /bypassed and are always be kept in service so

that in correct operation by line staff can be avoided.

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2.4(v) Occurrence at Bhusawal TPS on 13.02.2012 and 19.02.2012

MAHAGENCO representative explained the occurrence as below :

On 13.02.2012 at 15:53 Hrs station transformer No.II tripped on Y-ph differential protection.

Also, Generator transformer No.I tripped on R-Y-B phase differential protection and station

4B incomer OCB (6.6 kV) tripped on undervoltage protection at 16:25 hrs on same day.

This has resulted into tripping of unit-2. Similar incidence recurred on 19.02.2012 at 13:56

hrs wherein station transformer No.II has tripped. Both the times thorough checking was

carried out by station personnel but no fault had been observed by them.

Committee observed that the tripping of GTs on through fault should be viewed

seriously and the differential protection of the GTs be checked thoroughly for

saturation of the main/Aux. CTs. MSETCL representative informed that the GT on both

occasions tripped on Diff Protection for a Through fault.

2.4(vi) Occurrence at Padghe on 13.12.2011


On 13.12.11 at 20:12 Hrs at 220kV Padghe s/s 220kV R-phase stub bus conductor between

breaker to main bus isolator – I / II ahead of T-clamp in respect of 315MVA, 400/220KV

ICT-III broken ahead of T-clamp and fell on 220KV Main Bus-2 & gantry which grounded

and fell on underneath all the three phases of 220KV main bus-2, created the bus fault on

220KV Main Bus – 2 which is successfully cleared by ABB RADSS Bus bar protection.

Since 315MVA, 400/220KV ICT-III 220kV side was connected to 220kV Main Bus-I, also

created bus fault on Main Bus-1 for which RADSS operated successfully. This led to

tripping of all the 220kV feeders /ICT’s, transformers connected to Main- Bus-I and main

bus-II as shown in SLD placed at Annexure-2.4(vi).

Last thermo scanning done on 16.11.2011 temperature at T- clamp of stub bus noted to be

100°C which was attended on 25.11.2011 by replacing nut bolt during outage for

maintenance. The condition of stub bus conductor reported to be normal.

On analysis, it was found that the breaking of stub bus conductor may be due to old age

(substation was commissioned in 1995-96) & overheating being single conductor due to

continues carrying of full load ICT current and sustained through fault current over period of

time since commissioning.

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Remedial measures

The 220KV Bus is found to be very lengthy due to large number of bays of lines, ICTs

and TFs which are connected in grid and feeding the supply to major EHV s/s around. Due to

configuration of 3 bus system the stub bus in each bay is also there . As such outage and

maintenance of main & stub bus are difficult. To avoid the recurrence, above problems and to

improve the reliability of supply :

• bus sectionalizer are proposed for main bus I & II considering the importance of

Padghe s/s in western grid.

• existing BB protection ABB make, type RADSS to is proposed for replacement by

multi-zone Numerical bus bar.

• All stub buses of ICTs are of single conductor which is carrying almost full load

continuously & therefore needs to be strengthened with twin conductor. Meanwhile

all stub buses to be checked thoroughly to avoid the recurrences.

• The commissioning of fourth ICT (400/220 kV) to be expedited on priority

considering the load demand to avoid over loading of existing ICTs.

• To avoid overloading on ICTs, it is suggested that Nalasopara s/s to be fed from on

Padghe PGCIL Tap line PGCIL with in service at Padghe end also keeping Padghe –

Nalasopara feeder out.

Committee discussed the occurrence and remedial measures suggested by MSETCL.

Keeping in view the importance of Padghe s/s in the grid suggested that remedial

measures suggested by MSETCL above to be expedited to avoid such grid disturbance.

2.4(vii) Occurrence at 400 kV Karad on 22.10.2011


At 400KV R.S Karad, the 400 kV Zone 1 Bus bar protection operated due to bursting of

400KV Solapur (PGCIL) circuit breaker (Y-ph pole) at 17:05 Hrs and following breakers

connected to Bus-I tripped.

1) 400KV ICT-I 2) 400KV ICT-II 3) 400KV Lonikand 4) 400KV Kolhapur-I 5) 400KV New Koyana Ckt II

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The 400 kV Bus II Status: - 1) The 400KV Kolhapur –II kept off for over voltage. 2) 400KV ICT-III tripped due to over load. 3) 400KV Koyana-I remained in service. 4) 400KV Jaigad-II remained in service. Due to sudden load throw off & power swing 220 KV generating feeder’s i.e. 220KV

Pedambe, 220KV Pophali & 220KV Malharpeth tripped at remote end. The 220KV Bus

coupler tripped on backup O/C protection. So there was no power flow on 220KV Bus.

Committee observed that Bus Bar protection operated correctly.

2.4(viii) Occurrence at 400 kV New Koyna on 2.02.2012


On 02nd Feb 2012 at 14.47 hrs., there was heavy whirl wind (fem) due to which the plastic

paper of long length, might be along with conducting material got entangled with 400 kV

Karad -II gantry to main Bus - 1 Jumper of ‘B’ Phase resulting into operation of Busbar

protection (Zone-1) B phase & all the lines & ICT connected to Bus-1 tripped at the same

time. The operation of Bus Bar Protection Scheme (RADSS) Zone-I is in order & all the

feeders connected to Bus-I along with Bus coupler are tripped correctly. The Area affected in

this occurrence is NIL, as Bus II was in service.

Committee noted the same.

2.4(ix) Occurrence at 220 kV Chakan S/s on 24.02.2012


On 24.02.12 at 00:12 Hrs there was closer earth fault on 220 kV Chakan –Chinchwad line

and at the same time R-phase CT of 220 kV 3x105 MVA , 400/220 kV ICT-I bursted which

resulted into tripping of B/c , all transformers, feeders on 220 kV Bus-A. At the same time all

transformers, feeders on 220 kV bus-B also tripped. Chakan-Chinchwad line tripped on

distance protection zone 1 for which distance measured by the relay was 5 Kms from

Chakan. These trippings are normal but the tripping of other lines and transformer

connected on Bus-B are abnormal.

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On investigation the trip bus wiring, it was found that there was wrong shorting of X6.6 to

X6.8 instead of X6.5 to X6.7 as shown in fig.1 placed at

Annexure-2.4(ix). Correction shown in Fig.2 in the wiring modification in 220 kV TBC

relay panel is suggested by MSETCL.

Committee noted the incidence as above.

2.5 : Grid Incidences and Grid Disturbances classification as per the Grid Standards

notified by CEA.

POSOCO, WRLDC vide their letter No. WRLDC/OS/1658/2012 dated 23.05.2012 have

categorized the Grid Incidents and Grid Disturbance for the period Sep 2011 to Feb 2012

which are as below. Detailed reports in respect of following trippings have not been received

hence members of the PCM are requested to send the detailed reports so that the same can be

discussed and remedial measure can be suggested in next PCM :

TRIPPINGS IN SEP 2011

1. On 07/09/11 due to Bus fault at Chorania Bus 1 at 22:30Hrs, 400 x220 kV ICT-1 and

400 kV Asoj-Ckt I tripped. No load lost, no Generation loss.

2. On 11/09/11 at 20:41 hrs, due bus fault on 220 kV APL(Mundra) Bus-2, 220 kV

lines to Nanikhakhar (1,2) ;Tappar(1,2); ICT-2 and Unit-2 tripped. Gen loss was 310 MW

and no load Loss. All lines restored by 22:49 hrs. (GD-1)On 15/10/11 at 06:48Hrs, in

Maharashtra at Bhusawal (Khadka S/S), 400/132kV, 200MVA, ICT-I tripped due to

Buchholz relay operation leading to tripping of ICT-II and 400/220kV, 315MVA ICT on

over current. 220kV and 132kV bus become dead affecting load to the extent of 732MW

and Unit-3 generation of 167MW (GD-I).

3. On 24/09/11 at 14:42hrs due to bus fault at 400 kV Bhusawal Bus-I, 400/220 kV

ICT, 400/132 kV ICT, 400kV lines to Aurangabad and Koradi tripped, leading to no supply

at 400 kV. Bhusawal. Unit 3 hand tripped at 14:45 Hrs due to dip in frequency. Generation

loss was 145 MW and load loss was 300 MW. All feeders restored by 16:20Hrs. (GD-1)

4. On 29/09/11 at 05:27 Hrs., 220 kV Trombay (M)-ONGC tripped along with 220 kV

lines to TFPIL, Mulund,Kalwa,220kV Bus section III &IV at Trombay (T), separating

220kV Bus at Trombau with TATA Unit 5 &8, ICT 4 & 5 on one side and Unit 6&7 along

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with 220 kV Trombay(T) to Dharavi, Salset,carnac lines on other side.

At 05:44 Hrs. 110 kV Trombay Dharavi-1, Parel-Mankhurd and Khopoli-Lodhivali tripped

on over load forming Island of Units5 &8 with Trombay station A, Parel, Mahalaxmi, Grant

Road, Carnac, Chembur. Unit 5 & 8 tripped in the Island due to wide Frequency variation at

5:55 and 5:45 Hrs.. Load affected around 350 MW in TATA system. (GD-1)

TRIPPINGS IN OCT 2011

1. On 15/10/11 at 06:48Hrs, in Maharashtra at Bhusawal (Khadka S/S), 400/132kV,

200MVA, ICT-I tripped due to Buchholz relay operation leading to tripping of ICT-II and

400/220kV, 315MVA ICT on over current. 220kV and 132kV bus become dead affecting

load to the extent of 732MW and Unit-3 generation of 167MW (GD-I).

2 On 16/10/11 at 04:37Hrs, 110kV in TPC-Backbay (BEST) cable-II fire affecting

supply to south Mumbai of the order of 100MW up to 10:30Hrs. The complete network was

normalized by 19:30Hrs of 17/10/11(GD-I).

3 At 06:16:04 hrs on 31.10.2011 there was a bus fault at 220 kV Badod substation

leading to tripping of all feeders connected on 220 kV bus. No generation loss was reported

during the event. No significant change in frequency was observed during the event. This

incident would fall in the category-GI-1 as per CEA Regulation (Grid standards)-2010.

TRIPPINGS IN NOV 2011

1. At 16:59 hrs on 30th November, 2011 there was an occurrence at 400/220 kV Dhule

S/S due to bursting of B-phase pole of the circuit breaker of 400 kV Dhule – SSP-I feeder at

Dhule end that caused operation of bus bar protection at 400 kV Dhule bus-I and led to

tripping of all feeders on that bus and both ICTs at Dhule. Load loss of 500 MW

(approximately) was reported due to tripping of both the 400/220 kV ICTs at Dhule. 78 MW

generation loss occurred at SSP due to tripping of two running units at Canal head power

house (CHPH). This incident would fall in the category GD-1 as per CEA Regulation (Grid

standards)-2010.

TRIPPINGS IN DEC 2011

1. On 05/12/11 at 18:27 hrs K(W)-KSTPS S/C AND KSTPS-BALCO tripped, CT burst

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at KSTPS, KSTPS#5,7 tripped. Generation loss of 1000MW observed.(GD-I)

2. On 31/12/11 at 21:02 hrs JSPL-Raigarh-I, JSPL-Raigarh-II, CSPTCL Raigarh-PG

Raigarh-I, CSPTCL Raigarh-PG Raigarh-II and Raigarh-K(E) tripped and restored by 22:18

hrs.

TRIPPINGS IN JAN 2012

1. On 15/01/2012, Due to kite flying, 220 kV Vapi-Magarwada D/C tripped at 15:46 hrs

( ph-ph fault); 140 MW load of DD was affected in Varkund, Ringanwada and Kachigam.(

GD-I)

2. On 25/01/2012, all lines at Indirasagar HEP tripped at 22:27 hrs on O/V when 400

kV ISP-Nagda was being opened for high voltage. Gen loss 122 MW.(GD-I)

3. On 27/01/2012, all lines from 220 kV Khandwa tripped one by one from at 04:48 hrs

to 07:08 hrs; reportedly due to fog; No load loss.

TRIPPINGS IN FEB 2012

1. On 02/02/12, 220 kV Ichchapur Bus-I Bus bar protection operated at 19:05 hrs

tripping Kawas and Vav lines.

2. On 09/02/12 at 11:21 hrs, tripping of lines at Bhadrawati ( Raipur#3, Parli#1 and

Bhilai along with Chandrpur#7 )due to PLCC mal-operation. Gen loss of 400 MW(GD-1)

3. On 13/02/12, at 220 kV WPCL, Warora , at 08:18 hrs; line1 y-ph bus PT blast. All

units and other line tripped. Gen loss was 435 MW (GD-1)

4. On 26/02/12, 400/220 kV Dhule ICT#1 tripped at 15:06 hrs due to prv operation.

ICTs#2,3 tripped on overload. Load loss of 450 MW affected for 25 Minutes.(GD-1)

SE(Protection), WRPC stated that in respect of the incidences reported above for which

the details/reports are not available, respective constituents/members were requested to

submit the details (SLD of S/S along with relay indications and tripping details/reports

etc.) for discussion in the next PCM.

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ITEM NO. 3: Tripping of lines / ICTs:

The incidences of tripping of lines and ICTs during the period 01-09-2011 to 29-02-2012

were discussed and finalized . The same are enclosed at Annexure-3, 3A&3B.

Committee noted.

ITEM NO. 5: Other points:

5.1: Non-availability of Event Logger at 400kV state owned sub-stations at Nagda, Indore, Bina, Padghe, Kolhapur, Koradi, Chandrapur, Dhule and Bhilai.

Superintending Engineer(Protection), WRPC intimated that in the 104th PCM, PGCIL had

informed that Event Loggers at some of the 400 kV 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. In the 106th PCM, MPPTCL representative clarified that event

loggers available in the numerical relays as a built in feature, and GPS synchronized clock are

being used for logging the events at all the above S/S’s, hence they are not initiating the

procurement process for separate event loggers for the above S/Ss. 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. As desired by

MPPTCL the list of events that are required to be logged were enclosed at Annex. 5.3 of the

107th PCM minutes. The status of Event loggers as furnished by State Utilities during the last

PCM is as below:

MSETCL : Completed

MPPTCL: Tender invited but contract not awarded ; Estimated time required - 4months

CSPTCL : CSPTCL intimated that at Bhilai all lines except one, belong to PGCIL hence Event Logger may be installed by PGCIL.

MPPTCL , CSPTCL & PGCIL may update the status. PGCIL representative intimated that it is a standard practice to procure and install the

event loggers by respective owner of the sub-station and not by the ownership of feeders

and therefore claim made by CSPTCL during last meeting was not in the line with

followed procedure.

Committee noted as above.

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5.2: Problem in Bus bar protection scheme at Korba (W) CSPGCL 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 400kVKorba- 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 400kV 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 since the Bus bar protection is not available, the fault

was fed for longer time.

Earlier in the 107th PCM, 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 400kV

Korba (W) S/S and have initiated the process for procurement of the new same. Committee felt

that the commissioning of Bus Bar protection scheme at the above S/S may be expedited.

In the 108th PCM, CSPGCL representative informed that the Bus Bar protection scheme for

400kV Korba (W) has been included in their business proposal submitted to the Chhattisgarh

State Electricity Regulation Committee (CSERC) and after approval from CSERC the scheme

process for procurement of the scheme would be taken up. However Committee felt that in

view of the criticality of the matter and importance of the 400kV Korba (W) S/S from the WR

system protection point of view, the Bus Bar protection scheme at 400kV Korba (W) S/S,

might be taken up as a special case to CSERC and necessary approval may be obtained on

priority.

Follow up was made by WRPC vide letter No WRPC/Prot./PCM/2010-11/1013Dtd. 13th Aug

2010. Also the matter was put up before the 14th WRPC Board Meeting and CSPGCL was

requested to expedite the matter.

In 110th PCM, CSPGCL representative informed that the earlier proposal of BB protection

scheme was for 8 bays and in view of commissioning of 6 new bays at this S/S, the proposal

has been modified for 14bays. It is expected that approval of CSERC would be received in one

month and the procurement process would be initiated immediately. During the 111th PCM,

representative from CSPGCL was not present.

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CSPGCL intimate that CSERC have approved the scheme and procurement of the

same is under process and scheme will be completed within one year. On query by

SE(Protection), WRPC, CSPGCL representative intimated that the RADSS bus bar

protection scheme was out since 2007 and procurement of new scheme is under process.

5.3 Auto reclosure scheme on 400 kV Nagothane-Dabhol-I & II at Nagothane

MSETCL vide letter No. SE/TCC/VSH/Tech/0126 dated 15.03.2012 have intimated that they

have requested RGPPL to take 1 ph auto reclose scheme in service for 400 kV Nagothane-

Dabhol line I & II but reply from RGPPL is awaited. MSETCL have also intimated that auto

reclosure for 400 kV Padghe –Tarapur line I & II and 400 kV Padghe –Boisar (PGCIL) line

have been taken into service at their end.

RGPPL representative was not present in the meeting. WRPC Secretariat would

followup the matter with RGPPL.

5.4 Heavy disturbance of 400 kV lines and effect on Turbo generator at Chandrapur

STPS on 17.09.2011

CSTPS, MHAGENCO intimated that on 17.09.2011 at 7:45 Hrs heavy disturbance/variations

in generator parameters such as NPS current, MW of units 5,6, & 7 was observed

continuously till 08:20 Hrs which are detrimental to the turbo generator due to torsional

impact and may lead to tripping of units. MAHAGENCO further intimated that similar

incidence also occurred on 7.04.2011 and that time the problem in HVDC pole was reported

by SLDC, Kalwa.

MSPGCL representative stated that DR reports are not available for this incidence.

Committee opined that these oscillations are dangerous and can trigger the power

swing in the grid and therefore needs to be studied. It was informed by WRLDC that

PMV at Bhadrawati and Raipur Stn. with PDC at WRLDC have been commissioned.

Therefore MSPGCL were requested to intimate any future recurrence immediately to

SLDC and WRLDC so that the same can be studies in depth through PMU

data/SCADA data. MSPGCL representative agreed for the same.

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5.5 : Current Differential protection implementation using OPGW instead of Earth

wire for recommending to the PSDF Group.

WRLDC had proposed that replacement of old distance protection schemes with state of art

current differential protection scheme using OPGW instead of PLCC can be taken up under

PSDF. The PSDF group discussed the issue in its second meeting held on 19.10.2010 at

WRPC Mumbai and suggested that the same may be discussed in PCM and the decisions of

the PCM on this issue appraised to PSDF group of WRPC.

Protection sub-Committee felt that members from State Transmission Utilities would identify

at least two important lines having OPGW, in their system and accordingly, the lines

identified by utilities are as follows;

(i) GETCO

• 220kV Asoj-Chandrapura line - 25 Kms

• 220kV Nyara-Kangashiyali. - 25 Kms

(ii) MPPTCL

• 220kV Bina – Bina(PG) IC#1 - 8 Kms

• 220kV Bina – Bina(PG) IC#2 - 8 Kms

(iii) PGCIL WR-II

• Bina(PG) –Bina(MPPTCL) #1 - 750 Meter

• Bina(PG) - Bina(MPPTCL) #2 - 750 Meter

(iv) CSTPCL

• Khedamara-Bhilai #1 - 7 Kms

• Khedamara-Bhilai #2 - 7 Kms

(v) MSETCL

MSETCL vide letter dated 9.4.2012 have requested to consider following lines

• 220 kV Kalwa-Mulund - 7 Kms

• 220 kV Kalwa-Colorchem - 15 Kms

It was agreed during last PCM that as per agreed methodology, WRLDC shall work out the

cost estimate of the project and submit the same to WRPC in next meeting and then take up the

matter with PSDF body.

Member Secretary(I/C), WRPC intimated that a staff paper on management of PSDF

has been issued by CERC amongst all the constituents seeking the comments. It is

mentioned in the staff paper that PSDF accumulated is to be reversed to respective

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Region. Hence the above scheme can be implemented by some constituents or all the

above constituents till the decision regarding utilization of PSDF is finalized.

Committee noted the same.

5.6 : Review of 220kV Line setting at 2x220MW KAPS 1&2.

NPCIL have intimated that main(EE make SHPM-100 Static DPS) and backup( EE make

CDD-41 electromechanical directional O/C & E/F) protection is provided on seven nos of

220kV feeders. The relay settings adopted during the commissioning i.e. in the year 1990,

have not been reviewed/revised so far.

In view of changes in the grid and increase in fault levels, the existing relay settings needs

review. NPCIL representative made a presentation during the meeting and requested for

certain details for change in line configurations such as LILO, shortest line length etc. from

GETCO/PGCIL. GETCO/GSECL/PGCIL representative agreed to furnish the details

required by NPCIL.

Member Secretary(I/C), WRPC requested NPCIL representative to visit GETCO and

PGCIL, WRTS-II office at Vadodara and seek the details. He further requested

NPCIL to develop the scheme and place the same before Protection sub-Committee for

review.

NPCIL agreed for the same.

ITEM NO. 6.1: Repetition of PLCC frequency for various 400 kV lines under WRSS-II

& Mundra UMP scheme

ACE(Transmission), GETCO during the meeting intimated that PLCC frequencies already in

use on 400 kV at GETCO s/s are repeatedly used byPGCIL for 400 kV D/c

Ranchodpura(Vadavi)-Limbdi(Chorania), 400 kV D/c Ranchodpura-Zerda(Kansari), 400 kV

Ranchodpura-Bachau and 400 kVLimbdi(chorania)-Mundra commissioned under WRSS-II

and Mundra UMPP scheme without any concurrence fromGETCO. He further stated that as

per technical report, CE1, IEC 663:1980 clause No. 4.1.2.C, “The same frequency maybe

used for two different PLCC stubs working on lines forming common system if two are

separated by at least two line sections with intermediate sub stations.”

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He further stated that PGCIL has used frequencies already used in service for GETCO

without any concurrences from GETCO for other stations and warned that the practice of

utilizing repeated frequencies for PLCC may cause mal operation of system further causing

instability in the grid. He further intimated that 8 KHz band is used for every link.

PGCIL / WRLDC representative intimated that PGCIL might have used repeated

frequencies due to non-availability of the bandwidth. They intimated that elsewhere

four KHz band is used safely in the system and the problem of non-availability of

bandwidth can be resolved if 4 KHz band is used in GETCO. However, PGCIL would

confirm the same after consultation with WR-II. PGCIL/WRLDC to followup the

matter with WRTS-II, PGCIL.

ITEM NO. 6.2: Report of Fire Incident at BEST Backbay 110 kV RSS on 16.10.2011

MSETCL have forwarded the information regarding fire incidence received electronically

from BEST which is reproduced below :

On 16.10.2011, early morning, a fire incident at the incoming cable from Tata Power 220 kV

station at BEST Backbay 110 kV RSS occurred. This station supplies electricity to the

nearby areas of Navy Nagar, Colaba, Nariman Point, Churchgate, Hutatma Chowk and

Ballard Pier. The report of the incident is given below:

At about 4.37 am, supply of two of the three 110 kV incomers i.e. TBB2 (BAY- A2) and

TBB3 (BAY-AI) (BEST nomenclature) failed. These two incomers were switched out

Immediately and 110 kV Bus Coupler (BAY - E) which had supply from TBB-1 was

switched in and supply was restored. At about 4.45 a.m. there was an alarm on Fire

Protection Panel indicating problem at Battery Room and Cable Room in the basement. On

inspection of the Battery Room by shif-in-charge, everything was found normal. When he

tried to inspect the cable room he observed heavy smoke in the GIS room and could not go in

further. The fire brigade was alerted and they arrived soon. As such fire brigade insisted to

switch off supply before they enter the building for fire extinguishing operation. TBB-1

(BAY-A3) incoming 110 kV was switched out from TPC backbay RSS and fire was put out

in a short time.

Even though the fire was completely extinguished, no inspection of either the GIS room or

the cable room could be done as it was filled with smoke and it was extremely hot. Later on

the GIS Room was inspected and following were observed:

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Cable Termination on Circuit Breaker i.e. Cable No. TBB2 (BA Y-A2) was completely burnt

exposing the bare conductor. The adjacent 110 kV cable TBB3 (BAY-AI) was externally

affected. All the GIS circuit breakers were completely covered with black soot. The

incoming cable TBBI (BAY-A3) appeared to be not damaged. All the control cables of this

110 kV switchgear BAY were burnt resulting in loss of control and protection to the 110 kV

equipments. At the basement, cable TBB2 (BA Y -A2) has burnt and adjacent oil reservoir

which is used for maintaining the oil pressure in this oil filled cable also was found burnt.

Being a Sunday and naturally a low load period, supply had been restored using the alternate

feeds to the affected 33 kV RSS having normal feed from Backbay 110 kV RSS. However,

for Colaba and Navy Nagar being at the geographical dead end alternate feed was not

available and hence initially total shut down resulted. BEST pressed into service 55

generators and by connecting them to the affected distribution substation progressively

supply was restored to most of the affected locality of Colaba and Navy Nagar and marine

drive areas.

Simultaneously, necessary cleaning and testing of the right hand side bus section, which

appeared to be not damaged, was taken up including the checking of SF6 Gas condition and

Dew point and insulation values. It was ascertained that this circuit breakers could be taken

into service and accordingly the action was initiated. In the meantime, TPC confirmed that

the incoming cable TBB-1 (BAY -A3) was healthy and could be charged. By completing all

necessary actions the 100 MVA transformer, 110 kV/33 kV i.e, BAY C2 was taken into

service and the entire 33 kV Bus Section which is on a different floor at Bacbay 110 kV RSS

was taken into service by about 19.00 hrs. Necessary clearance of Electrical Inspector was

also obtained for taking into service these equipments.

Simultaneously one of the 33 kV cables, one feeding Navy Nagar DSS and another feeding

the Colaba DSS (F 1 and F2) was taken up for diversion to the adjacent 220 kV station at

Tata Power in order to avoid non-availability of alternate feed incase of any eventuality.

On 17.10.2011, the work of taking into service incoming 110 kV cable TBB-3 also started.

Simultaneously, TPC attended the damage to cable TBB3 and made it ready for charging.

With all these efforts, by 16.00 hrs TBB3 was charged along with Transformer BAY CI. The

110 kV feeder no.52 in the line diagram (BAY-B4) feeding to Nariman Point 110 kV

substation was also taken into service. The diversion of the cable for Navy Nagar and Colaba

was also completed at the same time and by 19.30 hrs. network was normalized and supply

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was restored to all.

As an interim measure, the protection system at nearby TPC station from which the cables

are emanating is being used as protection system for our backbay receiving station. The work

of providing protection to our system by laying necessary control cables is takenup on war

footing.

There were no casualties or injuries to any person in this fire incident.

Committee noted as above.

ITEM NO. 6.3: Revised islanding scheme in R-infra Mumbai transmission network.

In view of LILO of MSETCL Boisar-Borivali line at R-infra Ghodbunder EHV s/s and LILO

of Aarey-TPC Borivali Line-2 at R-infra Borivali EHV s/s following islanding scheme have

been implemented by R-infra :

47.9 Hz

R-infra end breaker opening at Versova for 220 kV Versova-Boisar line

R-infra end breaker opening at DTPS for 220 kV Dahanu-Boisar line

R-infra end breaker (sectionaliser-1&2) opening for Ghodbunder-Boisar and

Ghodbunder-Borivali lines keeping MSETCL-Boisar-Borivali line in service through

GIS Buscoupler at R-infra Ghodbunder EHV s/s.

Diagram enclosed at Annexure-6.3(i).

47.9 Hz + Reverse Power (power flow from R-infra to MSETCL)

MSETCL end breaker opening at Boisar for 220 kV Versova-Boisar line

MSETCL end breaker opening at Boisar for 220 kV Dahanu-Boisar line

Diagram enclosed at Annexure-6.3(ii).

47.7 Hz + Reverse Power (power flow from TPC to R-infra)

TPC end breaker opening at Borivali for 220 kV Aarey line

TPC end breaker opening at Borivali for 220 kV R-infra – Borivali line

Diagram enclosed at Annexure-6.3(iii).

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47.6 Hz

R-infra end breaker opening at Aarey for 220 kV TPC-Borivali line

R-infra end breaker opening at Borivali for 220 kV TPC– Borivali line

Diagram enclosed at Annexure-6.3(iv).

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

Superintending Engineer (Protection) requested MSETCL to host next meeting in mid

September-2012. MSETCL representative will revert back after consulting

management. Date and venue of the next meeting will be intimated afterwards.

Annexure-1

1 Shri J.N.Pancholi Addl. Chief Engineer (Testing)

2 Shri A K Kaul Addl. Chief Engineer(Gen.), Ukai

3 Smt. A V Pawar Superintending Engineer (FQAD)

4 Shri S.A. Jaolikar Superintending Engineer (Testing) Vashi5 Shri A M Kondawar Superintending Engineer (TCE), Nagpur6 Shri J G Nandapurkar EE (Trans-I), Mumbai7 Shri A D Karale Dy.EE, SLDC, Kalwa8 Shri D.P.Nandanwar Dy.EE(T) Vashi9 Shri A K Dhapare EE(Testing), Karad

10 Shri C L Bharamgunde Dy. EE(Testing), Karad11 Shri K F Rathod EE(Testing), Dhule

12 Shri M K Kanade Executive Engineer (T), Indore

13 Shri M Z Rehman Superintending Engineer , Bhilai

14 Shri N K Bizora Superintending Engineer , Korba

15 Shri Rajendra S Kachhia Dy. Engineer, ED, Silvassa

16 Shri K P Singh ACE(Trans.), NPCIL,Mumbai17 Shri D V Kodge SO/D(EMU), TAPS 1&218 Shri Nayan Shah SO/D(EMU), TAPS 3&419 Shri P Barik SE(EM), KAPS, Kakrapara

MSETCL (Maharashtra State Electricity Transmission Company Limited)

MPPTCL (Madhya Pradesh Power Transmission Corporation Limited)

MPPGCL (Madhya Pradesh State Power Generation Co. Ltd.)

CSPTCL (Chattisgarh State Power Transmission Co. Ltd.)

CSPGCL (Chattisgarh State Power Generation Co. Ltd.)

Electricity Department, DNH, Silvassa.

LIST OF PARTICIPANTS

114th Protection Committee Meeting held on 11th &12th June 2012 at WRPC Mumbai.

GETCO (Gujarat Energy Transmission Corporation Limited)

MAHAGENCO (Maharashtra State Power Generation Company Limited)

NPCIL (Nuclear Power Corporation of India Limited)

GESCL

20 Shri Oswald Menezes Sr. Mgr., NTPC,WR-I,Mumbai21 Shri Jitendra Tewari DGM (EMD-I/c) Vindhyachal STPS22 Shri R K Aash DGM(Elect.), NTPC, Kawas.23 Shri Prasun Chakraborty DGM(Elect.), NTPC, Sipat.

24 Shri Ravi A. Wadyalkar Manager ID, WRTS-I, Nagpur

25 Shri Vikas C. Jain Enggr., NSPCL, Bhilai

26 Shri J Srinivasa Rao Asst. Manager

27 Shri Girish Jawale Manager, Mumbai

28 Shri Hiren D Lakhani Manager, Ahmedabad.

29 Shri Dilip M Devasthale GM, R-Infra,Mumbai30 Shri M. R. Waigankar Sr. Manager (T&P), R-Infra, Mumbai31 Shri Javed M Patel Sr. Manager, Dahanu TPS.

32 Shri Aditya Agarwal GM (Tech.)33 Shri Kartikeya R Misra DGM (Elect.)

34 Shri P Pentayya GM, POSOCO, Mumbai35 Shri Abhimanyu Gartia DGM (OS/SS)36 Smt. Pushpa Seshadri Manager (OS)

37 Shri S D Taksande Member Secretary I/C38 Shri M M Dhakate Superintending Engineer (P)39 Shri O P Singh Superintending Engineer (C)40 Shri Satyanarayan S. Superintending Engineer (O&S)41 Shri D P Singh EE(Prot.)42 Shri L K S Rathore EE(Opn.)43 Shri P D Lone EE(Comml)

REL (Reliance Infra Ltd.)

KSK Mahanadi Power Co Ltd.,

TPC (Tata Power Company)

Torrent Power Ahmedabad

JSW Energy Ltd.

POSOCO WRLDC (Western Regional Load Dispatch Centre)

WRPC (Western Regional Power Committee)

PGCIL (Power Grid Corporation of India Limited)

NSPCL

NTPC Ltd. (National Thermal Power Corporation Limited)

ANNEXURE-3

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

of A/R (Yes/No)

REASON

Date Time Date Time1 400kV Korba 400kV Korba-Raipur

Ckt-3PGCIL

(Y)15-07-2011 01:23 15-07-2011 05:04 Line tripped on recpt of DT from Korba NTPC end

due to operation of Bus Bar protection while charging the Line.

2 400kV Korba 400kV Korba-RaipurCkt-4

PGCIL (Y)

15-07-2011 01:23 15-07-2011 04:50 Line tripped on recpt of DT from Korba NTPC end due to operation of Bus Bar protection while charging the Line.

3 400kV NTPC Korba (CG)

400kV Kor-Raipur Ckt-3

NTPC (Y)

01-09-2011 16:07 01-09-2011 16:07 Single Pole tripping occurred due to fault in L3 Ph at a distance 98.8 km from Korba end. A/R was successful.


400kV Kor-Bhilai Ckt-2

NTPC (Y)

04-09-2011 18:11 04-09-2011 19:09 At Bhilai end Line tripped on reactor protection(Mal operation, Bucholz relay contact replaced).Line is still charged from Korba end. Line Syn at 19.09 Hrs.

5 400kV STPS Sarnii S/S

400KV Sarni-Indra Sagar Line

MPPGCL (Y)

04-09-2011 08:40 04-09-2011 10:04 Sarni End- Main I/II prot. Optd. O/V Bus-I,YB , R-N Fault, Zone-1 Trip, RYB-Ph Remote End-N.A.


400kV Kor-Vin,chal Ckt-1

NTPC (Y)

08-09-2011 09:45 08-09-2011 10:02 Single Pole tripping at Korba due to fault in L2 Ph at a distance 72% from Korba.A/R was successful. 3 Ph tripping at Vin,chal end. Line Syn at 10.02 Hrs.

7 220kV ATPS Chachai S/S

220 kV AMK- Jab Ckt-1

MPPGCL (Y)

09-09-2011 20:17 09-09-2011 20:26 ATPS End- CN, Z-I, 86X Remote End- CN, Z-I.


220 kV AMK- Sukha Line

MPPGCL (Y)

10-09-2011 17:27 10-09-2011 17:44 ATPS End- A-Ph , Z-I, Bkr tripped, 186A,186B, 86A,86B, 86C. Remote End- Trip Ph ABC, Z-II, FTI, DPR Optd.



MPPGCL (Y)

13-09-2011 19:10 13-09-2011 19:30 ATPS End- A-Ph , Z-I, 86X, Lockout DPR Optd. Remote End- AN, Z-I, A/R , DPR Optd.


220 kV AMK- Kotmikala Ckt-2

MPPGCL (Y)

13-09-2011 19:30 13-09-2011 20:05 ATPS End- A-Ph , Z-II, 186A, 186B. Remote End- NIL


220 kV AMK- Sidhi Line

MPPGCL (Y)

13-09-2011 23:12 13-09-2011 23:51 ATPS End- A-Ph , Z-I, C/S, C/R, O/C, 86 M1A, 86M2A. Remote End- AN-Ph, Trip ABC, Z-I.



MPPGCL (Y)

13-09-2011 19:30 13-09-2011 20:20 ATPS End- A-Ph , Z-II, 186A, 186B. Remote End- 21XR, 21XY, 21XB.

13 220kV STPS Birsinghpur S/S

220KV BRS- Satna MPPGCL (N)

13-09-2011 14:18 13-09-2011 14:50 BRS End- tripped due to Ph-C, Z-III, DPR,186A, 186B. Satna End - Ph C N,ABC, Z-I Fault locator 68.3 Km.

14 400kV STPS Sarni S/S


MPPGCL (Y)

13-09-2011 06:10 13-09-2011 06:40 Sarni End- Main I/II prot. Optd. Trip Z-2 , B-Ph trip A/R. Remote End- Main -I, Main -II.


400kV Kor-Vin,chal Ckt-1

NTPC (Y)

15-09-2011 16:40 15-09-2011 16:40 Single Pole tripping occurred due to fault in L2 Ph at a dist 61% from Korba end.A/R was Successful.



MPPGCL (Y)

17-09-2011 12:05 17-09-2011 12:55 Sarni End- Main I/II prot. Optd. Z-I on B-Ph Trip, A/R fault locator 39.7% Remote End- Main -I, Main -II. Fault locator 62.9%

17 400KV Waluj 400KV Bhusawal-Waluj

MSETCL (Y)

18-09-2011 09:39 18-09-2011 14:06 R-Ph LA Burst at 400kV Bhusawal S/S,same got replaced and Line is OK.

18 400kV Girwali 400kV PRL-CHD Ckt-3

MSETCL (Y)

22-09-2011 23:07 23-09-2011 06:28 Line tripped due Transient fault at Ch,pur end.



MPPGCL (Y)

24-09-2011 11:20 24-09-2011 11:31 Sarni End- Main I/II prot. Optd. Z-I on B-Ph Trip, A/R fault locator 40.8% Remote End- Main -I, Main -II. Zone-I, Fault locator 61%



MPPGCL (Y)

25-09-2011 18:43 25-09-2011 18:57 ATPS End- A- Ph, Z-I, 86X, DPR Optd. Remote End- Trip ABC, Z-II, FTI, DPR Optd.


400KV Sarni- Koradi Line

MPPGCL (Y)

26-09-2011 06:01 26-09-2011 07:52 Sarni End- Main I prot.Trip. RYB Ph, Trip Zone-II, Fault locator 144.8Km, Main-II: B-Ph trip. Zone-II, fault locator 143.8 Km, Carrier recd. Lock out. Remote End- A/R , 186 A,186B.


220KV BRS- Pali Interconnector-I

MPPGCL (N)

29-09-2011 13:36 29-09-2011 14:07 BRS End- DPR, 186A,186B Pali End - RYB High Speed Relay.



MPPGCL (N)

29-09-2011 15:17 29-09-2011 19:07 BRS End- Earth fault relay Pali End - RYB High Speed Relay.


220 kV Sarni- Pandurna Line

MPPGCL (N)

01-10-2011 13:00 02-10-2011 18:26 Sarni End- PD, PAT,PE,PTaw,PSW. Remote End- N.A.


220KV BRS- Sukha MPPGCL (N)

02-10-2011 03:20 02-10-2011 03:44 BRS End- DPR, B-Ph,Z-I, 186A,86B,69.9 Km. Sukha End - DPR, C-Ph trip ABC,Z-I,81.85 Km.

26 400 KV Birsinghpur

400KV Bir-Damoh Ckt-1

MPPGCL (Y)

02-10-2011 14:17 02-10-2011 15:03 Line tripped due to A-ph E/F. fault location 112.7 Km from Brs end.Line was Syn at 15.03 Hrs from Damoh end.



MPPGCL (Y)

02-10-2011 15:17 02-10-2011 23:58 Line tripped due to R-ph E/F. fault location 131.2 Km from Brs end.Line was Syn at 23.58 Hrs from Damoh end.



02-10-2011 03:20 02-10-2011 03:44 BRS End- DPR, B-Ph,Z-I, 186A,86B,69.9 Km. Sukha End - DPR, C-Ph trip ABC,Z-I,81.85 Km.



03-10-2011 12:49 03-10-2011 13:09 BRS End- R-Ph N ,Z-Ifault ,L1-N,141 Km. Sukha End - DPR, AN, Z-I, 32.8 Km.



MPPGCL (Y)

03-10-2011 10:20 03-10-2011 15:41 Line tripped due to A-ph E/F. fault location 112.9 Km from Brs end.Line was Syn at 15.41 Hrs from Damoh end.


220KV BRS- Pali Interconnector-2

MPPGCL (N)

06-10-2011 14:13 08-10-2011 14:12 BRS End- DPR, C-Ph,Z-I,186A,186B. Pali End -OP trip, B signal trip failure high speed, LBB high speed,RYB B-Ph high speed relay.



MPPGCL (N)

06-10-2011 14:38 08-10-2011 14:58 BRS End- DPR, C-Ph,Z-I,186A,186B. Pali End - Charged ( Healthy)

TRIPPINGS OF LINES / ICTS

Tripping Restoration


400kV Kor- Balco NTPC (Y)

06-10-2011 11:02 06-10-2011 19:14 Line tripped due to single Ph fault in L2. 3 Pole tripping occurred just after A/R command fault reappeared in all Phases. Fault distance was 10.54 km from korba end.



06-10-2011 19:34 13-10-2011 19:09 Line was in charged condition from Korba.During Syn. Breaker trip command was given at Balco to reset Alarm and susequently direct trip code received at Korba and Line tripped.



MPPGCL (Y)

09-10-2011 20:37 09-10-2011 20:43 ATPS End- A- Ph, Z-I, 67X. Remote End- AN, Z-I.


220 kV AMK- Sukha Line

MPPGCL (Y)

10-10-2011 04:18 10-10-2011 04:50 ATPS End- C-Ph , 186A,186B, 86A,86B, 86C. DPR Optd. Remote End- CN-Ph, ABC Z-I., DPR Optd, FTI.



MPPGCL (Y)

10-10-2011 16:05 10-10-2011 16:50 Sarni End- Main I prot.optd. GT Trip Gr. A/B L/O Optd.direct Trip ,O/V Ist Stage optd. Remote End- N.A.


220KV BRS- AMK Ckt-III

MPPGCL (N)

10-10-2011 00:25 10-10-2011 01:15 BRS End- DPR, A-Ph, Z-I,ARR, 186A,186B. AMK End - DPR, A-Ph, Z-I, 37 Km.



12-10-2011 11:21 12-10-2011 17:59 BRS End- DPR, Z-I, L1-N,R-Ph, 19.6Km, 186A, 186B. S kh E d GTR t d Ph AN Z I 8640 400kV STPS

Sarni S/S400KV Sarni-Indra Sagar Line

MPPGCL (Y)

13-10-2011 13:32 13-10-2011 13:35 Sarni End- Main I : GT trip, RYB Ph trip, Zine-I, fault locator 40.1%., Main-II: TN &U, A/R relay, UD. Remote End- Main-I-GT, trip B-Ph, trip Zone-I,Fault locator 59.5%, Main-II prot.-D&T



MPPGCL (Y)

13-10-2011 12:00 13-10-2011 13:35 Sarni End- Main I : Prot. :GT trip RYB, Zone-I, fault locator 39.9%., Main-II: TN &U, A/R relay, UD. Remote End- Main-I-GT, trip B-Ph, trip Zone-I,Fault locator 58.7%, Main-II prot.-D&T



MPPGCL (Y)

25-10-2011 11:55 25-10-2011 12:04 ATPS End- C- Ph, Z-II, 67X. Remote End- C-Ph, Z-I, FTI.



MPPGCL (Y)

31-10-2011 07:09 31-10-2011 09:19 ATPS End- A B-Ph , 186A, 186B. Remote End- RY- Ph, Z-I, Lockout.



MPPGCL (Y)

31-10-2011 07:09 31-10-2011 10:08 ATPS End- B-Ph , 186A, 186B. Bkr Trip. Remote End- Z-I, Lockout.


220KV BRS- Pali Interconnector-2

MPPGCL (N)

09-11-2011 15:22 09-11-2011 15:56 BRS End- N.A. Pali End - Relay LDB high speed,RYB ,DPR opted, Z-I, 5.5 Km.


220KV BRS- AMK Ckt-II

MPPGCL (N)

09-11-2011 15:22 10-11-2011 07:29 BRS End- DPR, C-Ph, Z-I,186A,186B. AMK End - DPR, C-Ph,Z-I,186A,186B



MPPGCL (Y)

09-11-2011 13:28 09-11-2011 13:43 ATPS End- C-Ph , 186A, 186B. Remote End- 21XR, 21XY, 21XB, , B/U, O/C, DPR Optd.



MPPGCL (Y)

09-11-2011 15:18 10-11-2011 07:28 ATPS End- C-Ph , 186A, 186B. 86B, 86C DPR Optd.

Remote End- C-ph, Z-I, 186A, 186B. 49 220kV ATPS

Chachai S/S220 kV AMK- Jab Ckt-1

MPPGCL (Y)

13-11-2011 23:55 13-11-2011 24:00 ATPS End- C-Ph, Z-II, 86X, DPR Optd., Bkr Lockout. Remote End- CN-Ph, Z-I, FTAR, DPR Optd., A/R Optd.



15-11-2011 04:58 15-11-2011 05:15 BRS End- Tripped due to Z-I, A-Ph,186A,186B Satna End - Ph-AN, tripped A, Z-I,191.7 Km, 66%.


400KV Bir-Katni MPPGCL (Y)

24-11-2011 15:42 26-11-2011 15:28 BRS End-O/V tripping Katni End- O/V tripping, Distance Prot.


220 kV AMK- Sidhi Line

MPPGCL (Y)

25-11-2011 12:34 25-11-2011 12:55 ATPS End- CN, 86A, 86B, O/C & E/F. Remote End- CN-Ph, Z-I, FTI, trip ABC.

53 400kV Girwali 400kV GRL-CHD Ckt-2

MSETCL (Y)

27-11-2011 16:45 28-11-2011 07:36 Line tripped due to O/V in R-Ph, R-Ph CVT Replaced.



05-12-2011 18:26 05-12-2011 21:31 This line is connected to Bus-3, on the same Bus U-7 is also conneted.CT of U-7 failed subsequently B/B protection generated trip command to this line.


220 kV AMK- BRS Ckt-2

MPPGCL (Y)

05-12-2011 16:50 05-12-2011 17:09 ATPS End- DPR Trip, Bkr Lockout, C-Ph, Z-I, 1896A, 186B. Remote End- C-Ph, Z-I, Trip 186A, 186B.


220KV BRS- AMK Ckt-III

MPPGCL (N)

10-12-2011 17:07 10-12-2011 17:19 BRS End- A-Ph, Z-I,186A,186B. AMK End - A-Ph,Z-I, 186A,186B ,38.3 Km.



13-12-2011 16:36 13-12-2011 16:58 BRS End- Tripped due to Z-I, C-Ph,186A,186B Satna End - Healthy

58 400 KV Bhilai 400KV Bhi- Koradi CSPTCL (Y)

20-12-2011 00:45 20-12-2011 00:45 Line tripped due to Normal transient Fault and auto reclosed from both ends.

59 400kV Koradi S/S 400kV Koradi- Bhilai MSETCL (Y)

20-12-2011 00:45 20-12-2011 00:45 Transient Y-N fault, A/R at both ends successful. It is understood that Tie- breaker did not A/R at Bhilai end(PGCIL Line)



26-12-2011 19:50 26-12-2011 20:31 Line tripped on DT code received . At Balco end B/B protection operated due to fault in one of the ICTs connected to Bus.



MPPGCL (Y)

26-12-2011 22:10 26-12-2011 22:14 ATPS End- C-Ph, Z-I, DPR Optd., Bkr Lockout. Remote End- N.A.



MPPGCL (Y)

27-12-2011 02:18 27-12-2011 02:24 ATPS End- A-Ph, Z-I,DPR Optd, Bkr Lockout, 86X, Remote End- AN-Ph, Z-I, FTI.

63 400 KV Bhilai 400KV Bhi- Ch,pur CSPTCL (Y)

28-12-2011 09:10 28-12-2011 09:41 Line tripped from Bhilai end only.

64 400 KV Bhilai 400KV Bhi- Koradi CSPTCL (Y)

31-12-2011 21:04 31-12-2011 21:47 Line tripped due to Normal transient Fault and auto reclosed at Bhilai end only.

65 400kV Koradi S/S 400kV Koradi- Bhilai MSETCL (Y)

31-12-2011 00:21 31-12-2011 21:47 Line A/R at Bhilai end but went into L/O at Koradi end due to Y-N Zone-2 fault.A/R was not successful at Koradi end .line was syn from Koradi end at 21.47 Hrs.(PGCIL Line)

ANNEXURE-3A

1 400kV Raipur 400kV Raipur-Korba,Ckt-3

PGCILL (Y)

01-09-2011 15:44 01-09-2011 15:44 B-Ph to E/F, A/R successful at both ends.Fault location at 111 Km from Raipur End.

2 400kV Vapi 400kV Vapi- Boisar,Ckt-3

PGCILL (Y)

03-09-2011 18:15 03-09-2011 18:15 B-Ph to E/F, A/R successful at both ends.Fault location at 90 Km from Boisar End.

3 220kV Korba(E) 220kV Korba(E)-Buddipadar, Ckt-3

PGCILL (Y)

04-09-2011 18:10 04-09-2011 18:44 Line tripped due to over loading.

4 400kV Bhadrawati 400kV Bha,wati-Ch,Pur Ckt-1

PGCILL (Y)

06-09-2011 10:34 06-09-2011 11:03 Line tripped at MSEB,Ch,pur end due to PLCC maloperation.

5 400kV Raipur 400kV Raipur- RaigarhCkt-3

PGCILL (Y)

08-09-2011 15:06 08-09-2011 15:11 Line tripped due to O/V at Raigarh end..

6 400kV Raigarh 400kV Raipur-SEL(LILO of R,kela#2at SEL)

PGCILL (Y)

09-09-2011 04:06 09-09-2011 04:11 Line tripped due to O/V at Raigarh end..

11 400kV Soja 400kV Soja-WanakboriLine

GSPGCL (Y)

11-09-2011 05:02 11-09-2011 10:22 Line tripped due to O/V, A/R at both ends.


GSPGCL (Y)


7 400kV Raipur 400kV Raipur- SipatCkt-3

PGCILL (Y)

14-09-2011 22:04 14-09-2011 22:14 Line tripped due to O/V at NTPC Sipat end.

8 400kV Raigarh 400kV Raigarh-Rourkela Ckt-1

PGCILL (Y)

17-09-2011 18:15 17-09-2011 18:15 Y-Ph to E/F, A/R successful at both ends.Fault location at 165.2 Km from Raigarh End.

9 400kV Raipur 400kV Raipur-Bh,wati, Ckt-3

PGCILL (Y)

23-09-2011 12:06 23-09-2011 12:06 Y-Ph to E/F, A/R successful at both ends.FL at 151.4 Km from Raipur & 168 Km from Bha,wati end.

10 400kV Koradi 400kV Koradi- Bhilai PGCILL (Y)

26-09-2011 06:03 26-09-2011 07:07 Line tripped due to Busbar fault at Koradi (MSETCL) end.

14 400kV Korba 400kV Korba-Balco,Ckt-2

PGCILL (Y)

06-10-2011 11:02 06-10-2011 19:15 Line tripped on Y-Ph, E/F from Korba end at 10.54 Km.

15 220kV Korba 220kV Korba-Buddipadar,Ckt-3

PGCILL (Y)

07-10-2011 12:53 08-10-2011 16:27 Line tripped on R-Ph, E/F from Korba end due to smoke & fire to nearby tree and grasses.

16 400kV Bhadrawati

400kV Bha,wati-Parli,Ckt-1

PGCILL (Y)

08-10-2011 19:54 08-10-2011 20:31 R-Ph to E/F, A/R successful at both ends.FL at 218.75 Km from Bha,wati end.

17 400kV Ranchi 400kV Ranchi-Sipat,Ckt-2

PGCILL (Y)

09-10-2011 14:17 09-10-2011 14:17 Transient fault, A/R successful at both ends.FL at 317 Km from Ranchi & 88Km from Sipat.

18 400kV Seoni 400kV Seoni- Bhiali(LILO portion)

PGCILL (Y)

18-10-2011 14:55 18-10-2011 14:55 R-Ph E/F, A/R successful at both ends.FL at 165.6Km from Seoni.(fault in CSEB Portion )

19 400kV Kolhapur 400kV Kolhapur-Mapusa, Ckt-2

PGCILL (Y)

19-10-2011 18:58 19-10-2011 18:58 R-Ph E/F, A/R successful at both ends.FL at 106.7 km from Mapusa end.


GSPGCL (Y)


20 400kV Koradi 400kV Koradi- Satpura PGCILL (Y)

06-11-2011 04:03 06-11-2011 05:23 Y-Ph E/F, A/R successful at Satpura end at F/L 33 Km from Koradi , but A/R switch at Koradi was kept in Non Auto mode line tripped at Koradi end only.

21 400kV Bhadrawati


PGCILL (Y)

08-11-2011 10:32 08-11-2011 19:00 Line tripped on B-Ph E/F , FL at 107.5 Km from Bha,wati.

22 400kV Tarapur 400kV Tarapur-Padghe,Ckt-1

PGCILL (Y)

14-11-2011 16:31 14-11-2011 16:51 Line tripped at Padghe end only due to receipt of DT from Tarapur while testing of PLCC at Tarapur(NPCIL).

23 400kV Kansari 400kV Kansari-VadaviLine-2

GSPGCL (Y)

17-11-2011 10:31 21-11-2011 18:08 Disc String flash over at Loc No.131(s)

24 400kV Bhadrawati


PGCILL (Y)

19-11-2011 10:18 19-11-2011 10:23 Line tripped on O/V stage-1 at Bhadrawati end.


GSPGCL (Y)

21-11-2011 21:03 21-12-2011 14:41 Due to R-Ph CT fire of 400 kV Kansari-Vadavi Line-1

26 400kV Raigarh 400kV Raigarh-Rourkela,Ckt-3

PGCILL (Y)

24-11-2011 17:39 24-11-2011 17:49 Line tripped due to O/V at Rourkela end.

27 400kV Akola 400kV Akola-Aurangabad,Ckt-1

PGCILL (Y)

25-11-2011 14:40 25-11-2011 14:56 Line tripped at Aurangabad end only, due to DT receipt from Akola end.


PGCILL (Y)

27-11-2011 09:50 27-11-2011 10:00 Line tripped O/V at Rourkela.

29 PENCH HPS PENCH Unit-1(80MW)

MPPGCL 05-12-2011 23:14 05-12-2011 23:27 Unit tripped due to Neutral O/C relay operated.


MPPGCL 05-12-2011 23:14 05-12-2011 23:25 Unit tripped due to Over all Differential Protection operated.


GSPGCL (Y)


32 400kV Mahan(ESSAR)

400kV Mahan-Vin,chal,Ckt-1

PGCILL (Y)

16-12-2011 23:19 17-12-2011 00:41 Line tripped due to DT Received at Vin,chal end.


PGCILL (Y)

17-12-2011 19:17 17-12-2011 20:46 Line tripped due to O/V at Rourkela end.& DT received at Raigarh.

34 400kV Kasor 400kV Kasor-ChoraniaLine-1

GSPGCL (Y)

17-12-2011 17:33 17-12-2011 17:47 Over Voltage Condition

35 400kV Korba 400kV Korba-Mahan(ESSAR)

PGCILL (Y)

18-12-2011 00:25 18-12-2011 00:52 Line tripped at Mahan end only on receipt of D/T from Korba.

36 400kV Korba 400kV Korba-Mahan(ESSAR)

PGCILL (Y)

18-12-2011 14:33 18-12-2011 14:59 Line tripped on receipt of D/T from Korba due to relay mal oprn at Mahan(ESSAR).

37 400kV Mahan(ESSAR)

400kV Mahan-Vin,chal,Ckt-1

PGCILL (Y)

21-12-2011 12:57 21-12-2011 13:37 Line tripped due to DT Received at Vin,chal end.

38 400kV Kasor 400kV Kasor-ChoraniaLine-1

GSPGCL (Y)


39 400kV Raigarh 400kV Raigarh-SEL(LILO of Raigarh -Rourkela#2)

PGCILL (Y)

25-12-2011 22:10 25-12-2011 22:15 Line tripped due to O/V at Raigarh.


MPPGCL 27-12-2011 21:46 27-12-2011 22:15 Unit tripped on GT Neutral O/C.


31-12-2011 21:04 31-12-2011 21:19 Line tripped only at Koradi(MSETCL) end on B-Ph E/F. Fault Location 251.6 Km from Koradi.


ANNEXURE-3B

1 400kV Hadala 400kV Hadala-MundraLine

GETCO (Y)

01-01-2012 14:35 01-01-2012 16:09 No cause found

2 400kV Soja 400kV Soja-WancoboriLine

GETCO (Y)


3 400kV Korba 400kV Korba-Balco(LILO Line)

PGCILL (Y)

03-01-2012 06:24 03-01-2012 16:25 Line tripped on R-Ph E/F , fault location 10Km from NTPC Korba, Fault in Balco Section.


GETCO (Y)


5 400kV Kasor 400kV Kasor-SSP Line GETCO (Y)

16-01-2012 14:06 16-01-2012 18:29 No cause found


PGCILL (Y)

16-01-2012 15:12 16-01-2012 15:22 Line tripped due to O/V at both ends.


GETCO (Y)

20-01-2012 15:27 20-01-2012 17:36 Nothing found abnormal

8 400kV Bhilai 400kV Bhilai-Bhatapara PGCILL (Y)

21-01-2012 20:34 21-01-2012 21:05 Line tripped at Bhilai CSPTCL end only,due to PLCC maloperation.


26-01-2012 19:16 26-01-2012 19:16 Y-Ph E/F at both ends at a distance 42.78Km from Bhilai end., A/R successful.

10 400kV Kasor 400kV Kasor-SSP Line GETCO (Y)

01-02-2012 21:57 01-02-2012 22:17 Transient tripping, Test charge taken and line stood OK.

11 400kV Kasor 400kV Kasor-GPECLine

GETCO (Y)

08-02-2012 00:05 08-02-2012 00:25 Transient tripping, A/R operated successfully at both ends.

12 400kV Ranchi 400kV Ranchi-Sipat,Ckt-1

PGCILL (Y)

09-02-2012 01:15 09-02-2012 01:20 Line tripped due to O/V at Ranchi end.


PGCILL (Y)

17-02-2012 02:58 17-02-2012 03:08 Line tripped due to O/V at Rourkela end.

14 400kV Parli 400kV Parli-Parli,Ckt-2 PGCILL (Y)

23-02-2012 18:00 23-02-2012 19:17 Line tripped on O/V function operation of Relay.

15 400kV Bhadrawati 400kV Bhadrawati-Bhilai

PGCILL (Y)

27-02-2012 15:26 27-02-2012 15:26 R-Ph E/F at a distance 206.8 Km from Bhadrawati end., A/R successful at both ends.

16 400kV Chorania 400kV Chorania-HadalaLine

GETCO (Y)

29-02-2012 09:58 29-02-2012 16:12 No cause found abnormal


LIST - wrpc · The list of participants is placed at Annexure -1. ... (11)220KV J’buva-1...

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Transcript of LIST - wrpc · The list of participants is placed at Annexure -1. ... (11)220KV J’buva-1...