116 pcm agenda mail list - wrpcwrpc.gov.in/pcm/116pcm_agenda.pdf · 116 pcm agenda mail list 1)...

116 PCM AGENDA MAIL LIST

1) Chief Engineer (LD), MSETCL, Kalwa. 2) Chief Engr. (Trans O&M), MSETCL, Bandra. 3) S.E. (T&C), MSETCL, Aurangabad. 4) S.E (T&C), MSETCL, Pune. 5) S.E. (T&C), MSETCL, Nagpur. 6) S.E.(T&C), MSETCL, Nasik Road. 7) S.E.(T&C), MSETCL, Vashi. 8) S.E.(Gen.Tstg), MSPGCL,Eklahre, Nasik. 9) S.E. (Task Force), MSPGCL, Nagpur. 10) S.E.(TCC), MSETCL, Karad. 11) Chief Engineer (Gen), GSECL, H.O. Baroda. 12) Addl. C.E.(Testing), GETCO, Baroda. 13) Chief Engineer(LD), MPPTCL, Jabalpur. 14) E.D. (T&C),MPPTCL, Jabalpur. 15) Addl.C.E., MPPGCL, Jabalpur. 16) Chief Engineer (LD), CSPTCL, Bhilai. 17) C.E. (T&C), CSEB, Raipur. 18) EE (T) , CSPGCL,Raipur. 19) S.E.(T&C), CSPTCL, Bhilai. 20) S.E.(T&C), CSPTCL, Raipur. 21) E.E.(T&C), CSPTCL, Bhilai. 22) EE, Division VIII(MRT),Elect. Dept; Goa. 23) Supdt.Engr., Electricity Dept., DNH, Silvasa. 24) Executive Engr., Electricity Dept. DD. Daman. 25) D.G.M.(O.S. ),N.T.P.C., Mumbai, 26) D.G.M.(EM), KSTPS, NTPC, Korba. 27) DGM (EMD), VSTPS, NTPC, Vindhyachal. 28) DGM (EM-I), NTPC, SIPAT . 29) AGM(O&M), KGPP, Adityanagar, Surat. 30) Sr.Supdt. (EM), Gandhar, NTPC. 31) DGM (O.S.), WRLDC, Mumbai. 32) DGM, WRTS-I, POWERGRID, Nagpur. 33) Addl General Manager, WRTS-II, POWERGRID, Baroda. 34) SME (E), TAPS-3&4,Tarapur. 35) Maintenance Superintendant, TAPS –1 & 2,Tarapur. 36) SME(E), NPCIL , Kakrapara. 37) GM(Maint.). TORRENT Power., Ahmedabad. 38) AGM (ET&A),TPC, Trombay. 39) Dy.Gen. Manager, Dahanu TPS,Dahanu. 40) Vice President, Reliance Energy, Mumbai. 41) GM (Electrical), JPL, Raigarh. 42) AGM(OS), NSPCL, New Delhi . 43) Vice President(O&M), APL, Ahmedabad. 44) GM, RGPPL, Anjanwel, Guhagar, Ratnagiri, 45) GM, JSW Energy Ltd., Jindal Mansion, Mumbai. 46) GM, CGPL, Mundra. 47) Director (G M Division), CEA, New Delhi.

1 Agenda for 116th Protection Committee of WRPC

AGENDA FOR THE 116th PROTECTION COMMITTEE MEETING OF WRPC TO

BE HELD ON 28/29.01.2013 AT NAGPUR

ITEM NO.1: CONFIRMATION OF MINUTES OF 115TH PROTECTION

COMMITTEE MEETING.

Minutes of 115th PCM, held on 6/7.09.2012 at Pune, were circulated vide WRPC letter No.

Prot./115 PCM/2012/WRPC-9458 dated 26th September 2012.

No comments have been received.

Committee may confirm the minutes of 115th PCM.

ITEM NO.2: SYSTEM DISTURBANCES

2.1: System disturbances in CSPTCL/CSPGCL system.

2.1 (i) Occurrence at Sipat STPS on 14.09.2012

At 1852 hrs of 14.09.12 all the running units at Sipat tripped, resulting into a loss of around 2000 MW

generation alongwith lines emanating from Sipat. Frequency dipped by 0.814 Hz( i.e. from 49.911 hz

to 49.097 Hz). The df/dt rate reported from Raipur PMU was - 0.15 Hz/sec. There was no loss of load

but such huge quantum of generation loss and tripping of 765 kV lines would have resulted in a

catastrophic failure. In order to avoid such occurrence at Sipat, it was felt necessary to analyze this

occurrence in detail and come out with recommendations. Accordingly, a meeting was held on

21.09.2012 at NTPC office, Mumbai. The occurrence was discussed thread bare and following

recommendations were evolved. The complete record notes of discussion have already been

circulated to all and are available on website of WRPC.

• Committee recommended that in the event of using line reactor as bus reactor PLCC should

be switched off at both ends.

• Committee however felt that had CSR been used, the stresses on the breaker could have been

minimised and saved the occurrence. Also, in the event of non-availability of CSR, frequent

switching of reactor as bus reactor should be minimised to reduce stress on breaker.

• Committee opined that the non-operation of LBB is in order.

• Committee recommended that the characteristics and timing of the back up E/F protection

should be changed to IDMT on both sides of ICTs.


• Committee recommended that the timing delay of the 11 kV should be revised to 2-3 seconds

after necessary studies by NTPC.

Other issues & Recommendations (as suggested by GM, WRLDC)

1. Over voltage trip setting at Seoni end can be increased to 110%.

2. Manual control of backing down generation at JPL, Lanco etc.

3. Raise generation in Maharashtra in Koyna area

4. Proposal for one additional line from Sipat to Korba pooling station

5. Automatic control through new SPS

Further, CE(LD), MPPTCL vide letter dated 18.09.2012 addressed to Executive Director

(O&M:Gen.), M.P. Power Generating Co. Ltd., Jabalpur have intimated that disturbance occurred

at Sipat STPS on 14.09.2012 which caused tripping of 400 KV lines at 765 KV sub-station, Seoni.

The 400 KV STP-Seoni line tripped from Seoni end only and after about 15 minutes, the breaker

was hand tripped at Sarni end as the same was not tripped at STPS. In the past also this line was

tripped at Seoni end only.

In view of the above, CE(LD) requested to MPPGCL take following actions :-

(i) The testing and calibration of Bus Bar Differential Protection Scheme may be carried out.

(ii) Numerical Based DPRs should be installed on the 220 KV feeders and new Numerical

Based Bus Bar Differential Protection Scheme may be provided.

(iii) The remedial measure may be taken so that in the event of any fault, non-operation of

breaker tripping at Satpura end could be avoided.

(iv) The power station officials may be instructed for strict observance / compliance of

IEGC/MPEGC.

NTPC/MPPGCL/WRLDC may indicate the status. Committee may like to discuss.

2.1 (ii) Occurrence at Korba(E) and Korba(Extn) on10.09.12

At 17:34 Hrs, due to heavy flashover in R –Phase LA of the 220 kV Korba (E)-Korba(W) I/C

III while charging which led to collapsing of wave trap of same phase of the feeder and

snapping of the Jumper of 1P & 2P Bus of 220 kV Korba(E)-Korba(W) I/C I leading to

ground fault. The ground fault was sensed by all the generating unit and lines on Bus 1P and

2P as well as same was sensed by at 132 kV Korba(E) and Bango S/S. This led to tripping of


all the lines and feeders at 220 kV Korba (E), 220 kV Korba (E)-Extn,132 kV Korba (E) and

132 kV Bango S/S.

With the loss of generation of 560 MW, frequency dipped by 0.30 Hz( i.e. from 49.98 Hz to

49.68Hz). The df/dt rate reported from B’wati PMU was - 0.053 Hz/sec.

At 17:55 Hrs partial station supply was restored from 33 kV feeders .After that 220 kV 2P

Bus was charged from 220 kV Korba-Raigarh line and full station supply was restored. 220

kV 1P Bus was charged through 160 MVA Auto transformer I. With full restoration of 220

kV Bus at Korba (E), 220 kV Korba (E)-Balco-I & II wascharged and Balco-CPP1-GT-4 got

connected with grid. At 19:52 hours Korba (E) Unit 4 was synchronized with the grid. Then

after Unit 1 and 5 was synchronized. During the restoration work, at 22:58 132 kV Champa-

Banari I & II lines tripped on Over current protection from Champa end which led to

insufficient evacuation path from Korba(E). Due to this Korba(E) system became unstable

and wide fluctuation of frequency was observed(50 to 54 Hz). This led to tripping of all the

feeders and 220 kV on Bus 1P of Korba(E). Again the restoration work started in the same

manner. The tripping details from Korba(E) is still awaited as DR/EL files were unavailable.

Report received from WRLDC is enclosed at Annexure-2.1(ii).

Committee may like to discuss.

2.1 (iii) Occurrence at Korba, NTPC on 11.09.12

At 00:05 Hrs, due to operation of LBB protection of Bus-III at Korba Generating station, all

the elements connected with the bus become dead. This lead to tripping of Unit-5 and 7 at

Korba NTPC and Unit 1 and 2 at BALCO. 400 kV Korba- Raipur IV line tripped on earth

fault in R-phase On Zone-1 distance protection, The fault was temporary in nature and auto

reclosure operated successfully. But due to LBB-2 relay mal-operation occurred leading to

LBB protection operation on Bus-III. With the LBB protection operation (A of Bus-III at

Korba, all the connecting elements on this bus tripped. With the loss of generation of 1100

MW, frequency dipped by 0.547 Hz (i.e. from 49.749 Hz to 49.202 Hz). The df/dt rate

observed from Bhadrawati PMU was 0.0592 Hz/sec.

Report received from WRLDC is enclosed at Annexure-2.1(iii).



2.1 (iv) Occurrence at Bhilai on 30.10.12

At 12:23 Hrs on 30th Oct’12, due to failure of CVT/CB/LA of 220KV BSP-feeder I at

400/220KV Bhilai (Khedamara) Sub-station, 220 kV main bus tripped on bus bar protection.

Due to this, all 220 kV feeders emanating from Bhilai (Khedamara) tripped along with

400/220 kV ICT I, II and III. 400 kV Bhilai – Seoni S/C and 400 KV Bhilai – Bhadrawati

S/C also tripped simultaneously. 220 kV S/s Bhilai, Thelkadih, Gurur, Barsoor and 132 kV

S/s of Bhilai, Ruabandha, Kurud, Rajnandgaon, Dongorgaon, Gunderdhehi, Balod,

Dallirajhara, Kanker, Jagdalpur and Dongargarh were affected due to the occurrence.

Report received from WRLDC is enclosed at Annexure-2.1(iv).


2.1 (v) Occurrence at Jindal on 14.09.12

JPL have intimated that on 14th Sept’ 12 at 19:15 Hrs both 400KV JPL (Tamnar) – Raipur

Line 1&2 tripped on Direct trip command received from Raipur end. Which lead to tripping

of all running 03 Units of 250MW (one unit no. 2 was under AOH). The tripping of all units

and lines resulted in Black-out in O.P. Jindal Thermal Power Plant. In detailed analysis, it is

found that direct trip command received at JPL due to hand trip operation at Raipur end for

both the lines and message was received from POSOCO vide fax no. LD/9/1176 dtd.

14.09.2012 that opening of 400 KV JPL – Raipur lines from Raipur end due to an occurrence

at Sipat Generating Station. The other details and restoration time as below.

The generation loss due to tripping of JPL Unit was 756 MW Report received from JPL is enclosed at Annexure-2.1(v).


2.2: System disturbances in GETCO/GSECL system.

2.2(i) Occurrences at CGPL in July 2012 and September 2012

CGPL :2.07.2012

At 05:53 hrs on 2nd July, 2012 there was an occurrence at 440 kV CGPL-Mundra S/S due to

earth fault which resulted in operation of Bus-Bar protection. Prior to the incident, Main Bus-


1 & 2 along with GT-10, GT-30, Limbdi circuit-I & II, Bhachau circuit- I & II along with

line reactor (Limbdi-1, Limbdi-2 and Jetpur-2) and bus reactor on CGPL-Mundra 400 kV S/S

were in service. The weather condition on the day was foggy. At 04:19 Hrs, 400 kV

Mundra-Limbdi II got tripped on earth fault in phase B. Later at 04:29 Hrs main Bus-II at

400kV tripped on bus-bar protection due to bus support insulator failure located in Y phase.

Main Bus I voltage dipped from 236 kV to 5.54 kV in Y phase. After that 400 kV Mundra-

Limbdi II was charged with main bus-I at 05:00 Hrs. It again tripped due to earth fault in Y

phase at 05:37 Hrs. Around 05:50 Hrs, 400 kV Mundra-Limbdi I also tripped on earth fault

in Y phase. At 05:53 Hrs, Main Bus - I of CGPL Mundra 400 kV S/S tripped on Bus-Bar

Protection due to blasting of CB in R Phase. This led to the tripping of all the lines from the

400 kV bus and Unit-10 which was generating 685 MW at the time of incident went out of

service on protection.

CGPL : 30.07.2012

At 06:06 Hrs, due to tripping of 400 kV CGPL- Limbdi-II on Y-B Phase fault, 220 kV

Network from Bhachau also got tripped on over current which led to separation of CGPL

Units along with Bhachau load from the rest of the grid. Earlier to the event, 400 kV CGPL-

Limbdi-I was out due to R Phase to earth fault and 400 kV Bhachau - Ranchorpura I & II

tripped at 06:04 hrs on Y phase to earth fault. With separation of CGPL from the grid, Unit

20 immediately tripped while unit 10 operated with Bhachau loads for 50 Min. 400kV

Bhachau-Ranchorpura II was charged at 06:57 Hrs but it tripped on Y phase to earth fault at

06:58 Hrs causing power swing and led to tripping of Unit 10.

400 kV CGPL-Limbdi I and II were continuously tripping due to line to ground fault which

was reasoned out to be due to flashover of insulators. At 05:26 Hrs 400 kV CGPL-Limbdi I

got tripped again on R-Phase to ground fault nad was not taken in service due to persisting

fault. At 05:45 Hrs 400 kV CGPL-Limbdi II got tripped on B-Phase to ground fault and was

taken in service at 06:02 Hrs. At 06:04 Hrs 400 kV Bhachau-Ranchorpura I & II tripped on

Y Phase to ground fault and the generation at CGPL was reduced to supply Bhachau ICT and

400 kV Limbdi line II.

At 06:08 Hrs 400 kV CGPL-Limbdi II got tripped due to Y-B Phase fault. This led to

tripping of 220 kV lines from Bhachau due to over loading and Unit 20 got tripped while

Unit 10 came on Bachhau Load. Frequency Change :Grid frequency dropped from 49.97 Hz


to 49.09 Hz due to sepeartion of CGPL units from the rest of the grid leading to generation

loss of 1491 MW. Raipur df/dt observed during the incident was -0.08 hz/sec .

Restoration : Restoration was started by 06:57 Hrs by charging 400 kV Bhachau-

Ranchorpora II line from Bhachau end .The line got tripped on yphase to ground fault and

the Unit 10 observed power swing leading to its tripping on reverse power protection .This

led to loss of Swicthyard supply at CGPL. At 07:10 Hrs switchgears were charged via 220

kV Nanikhakar supply and at 10:13 Hrs 400 kV switchyard was charged. Around 19:10 Hrs

unit were ready in rolling condition but due to higher eccentricity of shaft it was shutdown

for further investigation.

This incidence was discussed in 115th PCM. Report received from WRLDC is enclosed at

Annexure-2.2(i).

CGPL : 31.07.2012

At 04:32 Hrs, due to tripping of 400kV Bhachau S/S last tie breaker (only 400 kV Mundra-

Bhachau 1 & 2 was in service with only tie breaker at Bhachau end in service,400 kV

Bhachau-Vadavi 1 & 2 and CGPL-Limbdi 1 & 2 were not available), Unit -20 of CGPL

resulted in islanding mode operation with 57 MW Bachau load. Unit was then manually

tripped after 39 minutes of low load operation.

At 00:45 Hrs:CGPL Unit -10 was out of service and Unit -20 was running at 325 MW load.

Main bus 1 & 2 ,GT # 1 ,GT#20,400 kV CGPL-Bhachau 1 & 2 , 400 kV Bhachau-Limbdi 2

along with its L/R were in service.400 kV Bhachau-Limbdi 2 was out due to breaker

problem. At 00:47 Hrs:Bhachau-Limbdi 2 line tripped on zone 1 protectionin R-Phase fault.

This line was charged again at 01:09 Hrs but again it tripped at 01:28 Hrs .Further it was

once again charged at 03:02 Hrs but this time it trippedon zone 1 Protection in Y phase fault

at 03:54 Hrs. At: 04:32 Hrs: With only 400 kV CGPL- Bhachau 1 & 2 in service with only

one tie breaker at Bhachau (out of 4 Tie-breaker, 2 Nos. oftie were out due to problem in CT

and 3 breaker opened during 400 kV Bhachau-Vadavi 2Tripping), the tie breaker tripped

resulting in islanding of 400 kV Main Bus 1 of Bhachau islanded from the grid. This lead to

load throw off of 268 MW and Unit-20 came on 57 MW Bachau load.

With the loss of generation, frequency dipped by 0.243 Hz ( i.e. from 49.953 hz to 49.710

Hz).


GM, POSOCO, WRLDC vide letter dated 9.10.2012 referring to Item No. 4.2 of the 115th

PCM have quoted as below:

“GM, WRLDC stated that there was communication problem between operators of

CGPL and WRLDC as house loading intimated by CGPL was not understood by

WRLDC as islanding of the station of house loading has a different connotation.

After receiving the code from WRLDC, the line Bachhau-Ranchodpura-II was

successfully synchronized at Ranchodpura through synchroscope at 06:58 hrs of

30.07.2012 and after one minute i.e. 06:59 hrs, the line tripped on Y-ph fault

indication. Probably the fault on this line might have caused instability on CGPL

unit.

Further, the codes are issued by WRLDC only after concerned agencies are ready

after inturn confirming the same from their respective substations. On 30.07.2012,

the data of Bachhau was not available and code was issued only after readiness of

CPCC(Jabalpur) and GETCO. The Ranchodpura S/s and Bachhau S/s had to

communicate regarding synchronizing conditions and Ranchodpura S/s was well

aware of synchronizing parameters as it was carrying out synchronization through

synchroscope. Also, as said earlier, the line was successfully charged for one minute.

CGPL : 18.09.2012

At 14:38 Hrs, due to spurious trip signal generatedfrom the system turbine protection scheme

of Unit-10 at CGPL tripped. At 14:38:09 Hrs due to spurious trip signal from turbine

protection scheme, generator circuit breaker opened and lockout relay operated, leading to

tripping of Unit-1o of CGPL.

With the loss of generation ,frequency dipped by 0.53 Hz ( i.e. from 49.77 hz to 49.24

Hz).The df/dt reported from Raipur PMU was - 0.035 Hz/sec. The tripping was initiated by

the malfunctioning of turbine protection scheme.

CGPL : 22.09.2012

At 17:04 Hrs, due to tripping of major auxiliaries on under-voltage, leading to boiler tripping

on low furnace pressure. This lead to tripping of CGPLUnit-10. At 17:04:52 Hrs due to

Under Voltage relay operation of FD Fan auxiliary of CGPL Unit-10, other major auxiliary


tripped which led to tripping of boiler on low furnace pressure.Unit-10 turbine got tripped on

boiler protection eventually leadingto lockout relay operation of Unit-10.

With the loss of generation ,frequency dipped by 0.363 Hz ( i.e. from 50.228 Hz to 49.865

Hz).The df/dt reported from Raipur PMU was - 0.033 Hz/sec.

It was found that the micro scada has generated the signal to open the the 11 kV bus breaker

which was supplying the 6.6 kV Bus. As the 11 kV bus became dead leading to under

voltage protection operation of auxilaries connected on 6.6 kV. So the mal-operation of

communication system of Micro SCADA for auxilary supply of Unit-10 led to tripping of

Unit-10.

Reports received from WRLDC is enclosed at Annexure-2.2(i).


2.2(ii) Occurrence at Kakrapar APS on 12.06.12

NPCIL vide letter dated 13.8.12 have intimated that on 12.06.12 at 19:47 hrs 220 kV bus

bar#2 tripped on bus bar differential protection. Switchyard survey was carried out just after

the incident. At the extreme end (13th bay) of the main Bus-II a section of R phase busbar

was found bent. Bus post insulator was found in snapped condition near R phase bus post

insulator structure and its base part was still intact on structure. Some of the broken insulator

pieces were found lying on the ground near support structure and on visual examination these

were giving the impression of freshly broken porcelain. Further, visual examination of

sheared BPI base indicated that 40 % area appear to be fresh one and remaining area having

dull appearance giving impression of existence of internal crack since long period.

On analysis, it was found that internal crack might be existed in insulator base area which

could not be detected during routine inspections and probably due to heavy wind force it has

caused insulator shearing off from its base.

Detailed report received from NPCIL is enclosed at Annexure-2.2(ii).



2.2(iii) Occurrence at APL Mundra in June 2012

APL Mundra :29.06.2012

At 4:52 hrs on 29.06.2012 Sami-Adani circuit I & II tripped on zone –I distance protection ,

SPS stage-II at Adani operated leading to tripping of Unit-5. This led to voltage dip which

caused the tripping of coal feeders of Unit-3 & 4 on under voltage. With the tripping of coal

feeders, critical flame loss was occurred and subsequently MFT acted which led to tripping

of APL Unit-3 & 4. Undervoltage was sensed in the system for more than 300 ms.

Frequency change was observed from 49.58 to 48.98 Hz.

APL Mundra :30.06.2012

At 01:22 hrs on 30.06.2012 due to tripping of APL-Sami-Dehgam-1 on zone-1 distance

protection, stage-II of SPS at adani operated leading to tripping of Unit-4. This led to

overloading of APL-Sami-Dehgam-II which resulted in tripping of Unit-5 due to operation of

Stage-III of SPS at Adani. Frequency change was observed from 49.52 to 49.10 Hz.

Report received from WRLDC is enclosed at Annexure-2.2(iii).


2.3: System disturbances in MPPTCL/MPPGCL system.

2.3(i) Occurrence at Amarkantak TPS 28.06.2012.

At 23:32 Hrs on 28.06.2012 there was an occurrence at Amarkantak TPS generating station

and 220/132 kV S/s due to CVT burst in R phase of the traction feeder no. 1. Due to bursting

of CVT, its flame directly created the bus fault. Due to this the 220 kV bus and 132 kV bus at

Amarkantak S/s became dead. This led to tripping of all the lines from these buses except

131 kV Amarkantak-shadol and Amarkantak-Rajmilan-II. With the tripping of evacuation

lines from Amarkantak S/s ATPS unit 3, 4 and 5 tripped.

Detailed report received from WRLDC is enclosed at Annexure-2.3(i).



2.3(ii) Occurence at Omkareshwar on 28.08.2012

On dtd. 28.08.2012 at 13.05 Hrs, MP System was running with NEW grid at frequency 50.17

Hz with available thermal generation 1252 MW and Hydel generation 1747 MW. MP was

drawing 733 MW against ISGS schedule of 815 MW. Generation at OSP was 364 MW. At

around 13.10 Hrs, it was observed that all seven running M/Cs at Omkareshwar got tripped

simultaneously. Further it was reported by OSP that 220 KV Omkareshwar-Khandwa line

tripped from both end on Y-phase to E/F indication on Zone-I. A tripping report of this

occurrence was received from OSP. In their report as indicated in DR/SER prints huge fault

current was fed by OSP generators and Khandwa (PG) ICTs. As per SER timings 220 KV

OSP-Khandwa line appears have been tripped at 13:10:05 Hrs, hence fault get cleared,

however running units started tripping from 13:11:45 Hrs except unit No.2. MPPTCL have

intimated that on 5.04.2012 at 00:30 hrs at Satpura TPS, 220 kV main Bus-I PT ‘B’ phase

(SCT make) got burst. Consequently busbar differential zone-I(R&B) phase and zone –II(R

phase) operated resulting into tripping of all lines and generators connected on Bus-I and

Bus-II. Generation loss of 470 MW has been reported. To avoid such recurrence the location

of existing PTs of 220 kV Bus-I have been shifted.

Detailed report received from WRLDC/MPPTCL is enclosed at Annexure-2.3(ii).


2.3(iii) Occurrence at Sarni STPS on 5.09.2012

At 10.00 hrs, MP System was running with NEW grid at frequency 49.97 Hz. MP was

catering demand of 3441 MW with available thermal generation 1163 MW, Hydel generation

1215 MW AND 1030 MW drawl from Central Sector against schedule of 1085 MW.

At around 10.13 Hrs, STPS 1, 2, & 3 got tripped. 220 KV Bus-I tripped on Zone-I on R & Y

and indication due to inrush of currents while charging 500 MVA ICT. Due to tripping of

Bus-I unit No.l, 2 & 3 and feeders connected with Bus-I, also tripped. Further after few

seconds, units & 220 KV feeders connected with Bus No. 2 also tripped. During

investigation, reason of tripping of bus No.2 could not be found by MPPGCL officials. Thus

both 220 KV bus became dead. It has been reported by MPPGCL that there was heavy rain

fall with dusty atmosphere and dense water particles were suspended in atmosphere in

switchyard.


Detailed report received from WRLDC/MPPTCL is enclosed at Annexure-2.3(iii).


2.3(iv) Occurrence at Tons HPS on 7.10.2012

MPPTCL have informed that on dated 07.10.2012 at 21.35 Hrs, MP System was running at

frequency 50.15 Hz NEW grid. At Tons HPS three machines were running on full load. At

around 21.40 Hrs, it was observed that all running machines got tripped and all outgoing 220

KV lines also tripped. Further it was informed by Tons HPS that B-Phase jumper between

breaker and line isolator of 220 KV Tons-Rewa Ckt. No.l snapped at Tons end. Fault on 220

KV Tons-Rewa I line has taken 8 ms to clear the fault on Zone-4 and 220 KV Tons-Satna &

220 KV Tons-Kotar also tripped on Zone-4 at Tons end. 220 KV Tons-Satna & Tons-Kotar

lines did not trip from remote end to clear the fault. Hence all three lines tripped from Tons

end and supply failed on 220 KV bus. Thereafter all three running machines tripped on over-

speed. Line protections settings at Tons, Satna, Rewa & Kotar needs to be checked to avoid

such type of unwanted trippings.

Detailed report received from MPPTCL is enclosed at Annexure-2.3(iv).


2.3(v) Occurrence at 220kV Burwaha S/s on 17.10.2012

MPPTCL have intimated that on 17.10.2012, MP System was running normal with NEW

grid at frequency 49.94 Hz. At 220 KV Burwaha S/s, shut down was given on 3x40 MVA for

maintenance work and 160 MVA X-mer was on load. Loading on all 220 KV lines

emanating from Burwaha sub-station was normal. At around 12.54 Hrs, B-phase tension

string towards 160 MVA X-mer has failed and this has created bus fault on 220 KV Main

bus. All 220 KV lines emanating from Burwana 220 KV sub-station tripped from remote end

on Zone-II and total supply failed on 220 KV Bus. Load from 132 KV bus was managed and

there was no any interruption in the adjoining sub-station.

Detailed report received from MPPTCL is enclosed at Annexure-2.3(v).



2.3(vi) Trippings in MP system due to WRLDC action on 27.10.2012

MPPTCL have informed that on 27.10.2012, at around 21:27 Hrs. on dated 27.10.2012 MP

system was running at frequency 50.07 Hz with the system parameters as given below:

Thermal Generation :1757 MW (ex-bus) Hyde! Generation :1687 MW Central Sector Schedule: 3610 MW Central Sector Drawal :4029 MW Overdrawal :419 MW

WRLDC has given a fax message at 21:30 Hrs. to curtail overdrawal without indicating the

system frequency and any constraint. Though there was no violation of IEGC / Ul

Regulations, the fax message received from WRLDC was forwarded to all DISCOMs to take

adequate load shedding to curtail overdrawal. All the three DISCOMs have taken load

shedding and its effect was observed in decreasing trend of overdrawal. It was also informed

telephonically to Shift Incharge WRLDC that overdrawal is in decreasing trend and hence

they may not open any EHV line.

It may be seen from the system over-view that by 21:50 Hrs. MP overdrawal was reduced

from 419 to 332 MW i.e. 87 MW and was in decreasing trend, however, WRLDC has

unilaterally and without intimating MP-SLDC opened 220 kV Damoh (PG) – Tikamgarh

(MP) line without intimating to SLDC even without exchange of code.

Trippings : As soon as 220 kV Damoh (PG) - Tikamgarh (MP) line was opened by WRLDC,

load of 160 MVA transformer at 220 kV Tikamgarh Sub-station shifted to 220 kV

Chhatarpur Sub-station. Load on 160 MVA X'mer at 220kV Chhatarpur Sub-station reached

beyond 150 MW and it got tripped from 132 kV side. Subsequently, total load shifted on 132

kV Damoh-Hatta link which also tripped on overload.

Interruption : On account of trippings that took place as mentioned above, there was a load

loss of about 160 MW for 10 to 15 minutes and total interruption occurred to following 220

kV and 132 kV Sub-stations given below:

1) 220 kV S/s Tikamgarh 2) 220 kV S/s Chhatarpur 3) 132 kV S/s Tikamgarh 4) 132 kVS/s Prithvipur


5) 132 kV S/s Jatara 6) 132 kVS/s Khajuraho 7) 132 kVS/s Bijawar 8) 132kVS/sHatta 9) 132 kV S/s Narsinghgarh

MPPTCL have concluded that the situation would have been prevented if WRLDC operating

staff had acted in compliance with lEGC, Ul regulations and operating procedures which

clearly state that Type A,B & C messages need to be given if there is overdrawal below

frequency 49.8 Hz. WRLDC has stopped giving Type A, B & C message and a simple

message without indicating frequency and nature of threat in the Grid.

Detailed report received from MPPTCL is enclosed at Annexure-2.3(vi).


2.3(vii) Occurrence at Birsinghpur on 8.11.2012

MPPTCL have informed that on 08.11.2012 at around 13.53 Hrs, at SGTPS, bus-bar

protection operated at 400KV bus-II. This has resulted into tripping of 500MW unit No.5 and

400KV Birsinghpur-Damoh I &II, 400KV Birsinghpur-Balco feeder. As reported by SGTPS

officials, bus-bar protection on bus-II mal-operated and kept off for testing and checking of

protection.

Detailed report received from MPPTCL is enclosed at Annexure-2.3(vii).


2.3(viii) Occurrence at Birsinghpur on 10.11.2012

MPPTCL have informed that on at around 05.30 Hrs, flashover observed in B-phase Bus-II

isolator of 400 KV Birsinghpur-Damoh- I PGCIL feeder at Birsinghpur. Subsequently all

400 KV feeders along with 500 MVA ICT (400/220KV) & 210 MW running units No.2, 3, 4

& 500 MV unit No.5 also tripped. Faulty section was isolated and system was normalized in

due course of time.

WRLDC in their report have intimated that at 05:31 Hrs on 10th Nov’12, as the bus bar

protection of Birsinghpur was kept out of service , the flashover in B-Phase Bus II isolator


of 400 kV Birsingpur-Damoh -I line led to feeding of the fault to all the feeders connected in

Bus-II. This resulted in tripping of all the feeders from Bus-II and the delay in tripping of

400/220 kV ICT led to sensing of these fault by 220 kV side generators and their tripping.

During that time 400 kV Damoh-B’pur ckt-I was undergoing LILO work at Katni which was

completed by 9th Nov’12 and the line is at present 400 kV Damoh-Katni I and Katni-B’pur I.

The system was restored immediately by taking out Bus Bar protection for inspection.

The 400 kV B’pur –Damoh -II was hand tripped by station operator by mistake instead of

faulty line 400 kV B’pur-Damoh I. On analysing the event, it was found that the protection

scheme being used at 400kV Birsinghpur is of non-numerical in nature. The delayed tripping

of 400/220 kV ICT which led to feeding of fault to 220 kV side eventually resulted in

tripping of units is also an issue which need to be investigated. Also operating the system

without any bus-bar protection was very undesirable and made the whole system vulnerable.

Such practices may be avoided.

Further, ED(Engg), MPPGCL vide letter dated 3.12.2012(enclosed at Annexure-2.3(viii-a))

have raised concern due to failure of equipment on PGCIL feeder at early spans which are

offering threat to operation of thermal units by which MPPGCL will suffer heavy financial

losses and create major system disturbance.

Detailed report received from WRLDC/MPPTCL is enclosed at Annexure-2.3(viii-b).


2.4: System disturbances in MSETCL/MSPGCL system.

2.4(i) Occurrence at 400 KV Girwali S/S on 9.07.2012

MSETCL have intimated that on 9th July 2012 at 16:02hrs, 400 kV Bus bar protection of

MainBus-2 at 400KV Girwali Substation operated.

Analysis : The busbar protection has operated for a bus zone 2 fault as operating current for

A phase exceeded 80% of restraining for that phase. The busbar protection disturbance record

shows presence of AC fault throughout the fault duration. All the line and ICT at Girwali end

fault records also show presence of AC fault in reverse direction (i.e. towards bus) except the

PowerGrid circuit 2. The PowerGrid circuit 2 has extended Zone 1 tripping at both ends.

The PowerGrid circuit 2 & busbar protection records indicate presence of a fault involving


bus and line (A phase of bus and C phase of line). The fault current recorded is @ 12000A.

From the PowerGrid circuit I & 2 records some problems with respect to instrument

transformer secondary grounding were also suspected.

MSETCL have further intimated that on switchyard inspection; it is observed that in

PowerGrid ckt 2 bay; the clearance between A phase of main bus 2 and C phase of stub bus

(line in effect) is less compared to other phases. A fault at this location can produce current

distribution as seen in the disturbance records. The PowerGrid Engineers informed that the

tripping of both PowerGrid circuits at their end in Zone 1 was due to Zone 1 reach being set

to 120% wrongly. The same is now corrected by them. . It was observed that the instrument

transformer grounding in Powergrid bays was carried on relay panel side. Further tracing

revealed that these panel side earthing strips get connected to cable trays in the cable gallery

and not to the earth mesh directly. The connection point at cable trays shows some black

markings. . This kind of earthing can create problems in relay measurement. In PGCIL Ckt I

& II the distance protections are connected to the CT cores with Knee Point voltage 1000V

and Bus bar protec;ion is connected to 4000V. This is not matching with the approved

drawings.

Report received from MSETCL is enclosed at Annexure-2.4 (i)


2.4(ii) Occurrence at 220 KV S/S Mudshingi on 10.07.2012

On 10.07.12 at 22:20 hrs, 220 KV Talandge- Mudshingi- I line tripped on distance protection.

’R’ Phase Pilot insulator string flashover took place at location number 8 (12.51 KM from

Mudshingi) on 220 KV Mudshingi-Talandge ckt.- 1. 220 KV Mudshingi- Talandge - 1 CB

tripped from Mudshingi end in Zone - 1. From Talandge end the fault was sensed by the

relay in Zone - 2 correctly and the trip was initiated by both Distance and Earth fault relays.

Circuit Breaker ’Y’ and ‘B’ pole opened but due to mechanical problem, ‘R’ ph. Pole

failed to open at Talandge. This is not sensed by LBB protection, since LBB element of

this feeder found faulty. Due to mechanical problem in CB of 220 KV Talandge- Mudshingi

Ckt- I, delayed operation of PDR & also problem in LBB, the remote end tripping of source

feeders occurred.

MSETCL have further intimated that after analysis PDR time lag found 500ms (AREVA

Make) and ‘R’ phase LBB element of 220 KV Talandge – Mudshingi Ckt- I was found


faulty. The timing of PDR was kept 150ms & faulty LBB element was replaced.

Report received from MSETCL is enclosed at Annexure-2.4 (ii).


2.4(iii) Occurrence at 220 KV S/S Wardha on 15/16.08.2012

On 15.08.2012, 220 KV Wardha-Khaparkheda line (107 KM) tripped at @ 23:18 Hrs on

distance protection from both ends. The Ckt auto-reclosed at Khaparkheda end successfully.

At 220 KV Wardha S/S, B-ph trip command issued by the distance relay (Make: Siemens

Type:7SA611)of 220 KV Khaparkheda feeder and fault was isolated; A/R close command

was issued to breaker but since B-pole closing coil was burnt, breaker did not close and

finally tripped on PDR. A/R close command output contact of relay binary output damaged.

At 23:40 Hrs, trial taken by AE, shift incharge to charge the line through main breaker in

local mode from yard but breaker did not close and again tripped on pole discrepancy. Line

was in charged condition from Khaparkheda end and charging current was about 40A which

was normal. Hence it was decided to charge ckt through TBC. At 00:45 Hrs on 16.08.2012,

after carrying out necessary operation to shift 220 KV Khaparkheda ckt on TBC, TBC

breaker closed. But immediately tripped with distance protection on B-ph, Z-1,General trip

indication with distance 7.6 KM, IL3=10.51 KA, B-ph O/C relay, 86B, the operation of

internal LBB feature of 220 KV Busbar protection (Make: NR electric, Type: RCS915). Due

to operation of LBB protection of 220 KV Khaparkheda feeder at Wardha S/S, all feeders

connected to 220 KV bus including 220 KV Khaparkheda ckt tripped and 220 KV bus

became dead. Load @ 270 MW was affected due to above trippings. At about 01:05 Hrs on

dt.16.08.2012, 220 KV bus at 220 KV Wardha S/S charged from 220 KV Warora S/S and

stood Ok. Normalcy of rest of the feeders and T/Fs except 220 KV Khaparkheda ckt

restored one by one latest by 01:43 Hrs. At about 06:04 Hrs, after replacement of closing coil

of main breaker of 220 KV Khaparkheda Ckt and after taking trip-close trials of breaker,

second trial of breaker with auto reclose OUT was taken but again tripped on distance

protection on B-ph, Zone-1, General trip indication with distance=7.4 KM, IL3=10.32 KA

and 3-ph trip relay 186. Breakdown was declared on line.

In line patrolling at location no.315 cut point, insulator string found burst and conductor

found snapped. After attending line breakdown, the line charged on dt.16.08.2012 at 19:58

Hrs and stood OK.


MSETCL further intimated that at 220 KV Wardha S/S, Single bus system (1 M+1 A bus

arrangement) is provided for 220 KV bus. On patrolling of line on dt.16.08.2012 at location

no. 315 at cut point, B-ph string insulator found burst and conductor found snapped which

created fault. Hence tripping of line on distance protection at both end is in order. Due to

opening of conductor, fault was created towards wardha end. The line auto-reclosed at 220

KV Khaparkheda S/S successfully. At Wardha S/S due to burning of closing coil of B-ph

pole of 220 KV Khaparkheda feeder breaker, the line did not reclosed though the A/R

command was initiated by distance relay and line tripped on PDR. At about 00:44 Hrs, the

line charged through TBC due to problem in main breaker. Due to persistent fault, distance

protection and back up protection were operated but TBC breaker did not trip. Hence LBB

protection of 220 KV Khaparkheda feeder operated (Internal feature of Busbar scheme).

From the distance relay event log, it was observed that auto reclose was not disabled. Auto

reclose gets disabled when N/T switch is shifted to ‘T’ position. This indicates that N/T

switch was not shifted to ’T’ position before closing of the TBC breaker. As the N/T switch

was not shifted to ‘T’ position, protection of Khaparkheda ckt was not transferred on TBC

breaker, Hence trip command due to operation of distance protection and back up O/C relay

was not extended to TBC breaker. Due to external LBB initiation through distance and back

up protection to bus bar protection relay, re-trip command issued after 100 msec to

Khaparkheda breaker from bus bar relay which was not extended to TBC breaker. Hence

fault current was persisting. Thus internal LBB function of bus bar relay operated after 200

msec which issued final trip command to all breakers including TBC. About 10.77KA current

in B_ph was recorded by busbar protection relay (Type:RCS915). Thus the operation of LBB

protection is IN ORDER though undesired.

MSETCL have suggested following remedial actions :

1. It is essential to wire up the closing interlock of N/T switch contact in remote closing of TBC breaker where-ever it is not available. In the present case, it is not available in the scheme. Instructions have been issued to make necessary modification in the scheme.

2. Aux relay should be used in A/R reclose ckt where it is not available. Reclosing command is to be routed through contact of aux. relay.

Report received from MSETCL is enclosed at Annexure-2.4(iii).



2.4(iv) Occurrence at 220 kV Khaparkheda on 22.08.2012

At 09:40 Hrs on 22.08.12, due to Y phase CT blast of 40 MVA station transformer-III there

was smokes and fumes leading to conductive medium formation. This led to bus fault on

220kV Main Bus-I and initiate the tripping of all elements connected on Bus-I. This resulted

in tripping of Khaparkheda Unit 1 and 3. Also at the same time due to flame failure

Khaparkheda Unit 2 also tripped leading to a total generation loss of 397 MW.

40 MVA Station Transformer-III was connected to 200 kV Main Bus-I on differential and

backup protection. Y-Phase CT bursting of this T/F led to smokes and fumes which created

conductive media and resulted in 220 kV Main Bus-I fault. This led to operation of bus bar

protection of Main Bus-I which caused the tripping of all connected feeder as well as the bus

coupler. Unit 1 and 3 tripped due to operation of bus bas protection. Due to flow of zero

sequence current through the 220 kV side CTs of 400/220/33kV 500 MVA ICT-2 at 400 kV

Khaparkheda S/S, ICT-2 tripped on Y & B Phase differential protection. This was due to the

dual side earthing of 220 kV CTs which provided the conducting path to zero sequence

current. Unit-2 which was on Main bus-2 is has tripped during the occurrence due to flame

failure and not due to operation of any electrical protection.

Report received from WRLDC is enclosed at Annexure-2.4(iv).

MAHAGENCO/MSETCL is requested to furnish complete details. Committee may

like to discuss.

2.4(v) Occurrence at 400 kV Wardha S/s on 8.10.2012

SLDC, MSETCL reported that 400 kV Wardha-Mouda-1, Akola-1 and Warora-1 lines

tripped on overvoltage while charging 765 kV Wardha-Seoni-II at 9:54 hrs on 8.10.2012.

Also, 765 kV Wardha-Seoni-II tripped simultaneously. As AMPL at Tiroda was evacuating

power on 400 kV Tiroda-Warora-Wardha on single circuit, due to tripping Wardha-Warora

line, AMPL Unit-1 lost due to no evacuation affecting 375 MW short term open power

schedule to MSEDCL. SLDC control room was not intimated prior about any charging.



2.5 Occurrences at Goa

North Goa : 8.10.2012

At 04:04 Hrs, 400 kV Kolhapur-Karad I, Kolhapur-Mapusa-I, Karad –New Koyna-I and

Karad -Jaigad I lines tripped on over voltage. This led to loss of feed to Goa from WR Grid

as the other 400 kV and 220 kV Lines from Kolhapur were already out to control H/V. The

complete Goa load except Vasco tripped and led to 250 MW load loss.

400 kV Kolhapur-Mapusa II and Karad-Kolhapur II were already out on high Voltage. 220

kV Mapusa-Ponda I LILOed at Amona and Kolhapur-Ponda and Tillari-Ponda are LILOed at

Amona. These circuits are named as Amona-Ponda-I (Mapusa Line), Amona-Ponda-II

(Kolhapur Line) and Amona-Ponda-III (Tillari Line). Amona-Ponda-II and Amona-Pond III

were opened fromPonda end at Gantry at 23:40 Hrs on 7th Oct, 12 by Ponda to control High

Voltages on lowerKV levels. At 04:04 Hrs, 400 kV Kolhapur-Karad I, Kolhapur-Mapusa-I,

Karad –New Koyna-I and Karad -Jaigad I lines tripped on High Voltage. This led to loss of

feed to Goa from WR Grid leading to load loss of 250 MW. Vasco Load (15 MW) got

transferred to REL in island mode. Restoration:Initially after the occurrence the alternate

power of 110 MW was availed from SR grid to meet the VIP/Domestic loads. Vasco load got

transferred to REL in island mode. The Old MSEB Circuits from Amona were restored at

06:25 Hrsand 400 kV Kolhapur-Mapusa D/ C at 06:35 Hrs. System was successfully

normalized by 07:00 hrs.


Goa : 24.10.2012

At 17:10 Hrs, due to failure of jumper 220 kV Kolhapur-Ponda I tripped which led to total

loss of supply to Goa. Prior to the event others lines werenot available to Goa due to tripping

of 400 kV Kolhapur-Mapusa II on over voltage and 220 kV Tillari-Amona and 220 kV

Mahalaxmi-Amona on DPR operation. This led to complete loss of Goa load i.e. 244 MW.

At 16:33 Hrs, 400 kV Karad-Kolhapur I Tripped on Over-voltage ( Ckt II was already out to

control H/V). At 17:05 Hrs: 400 kV Kolhapur-Mapusa II tripped on Over-voltage ( Ckt I was

already out to due H/V). Now Goa was connected with WR region from220 kV Kolhapur-

Ponda I (Ckt II was out for retrofitting work ). At 17:09 Hrs: 220 kV Tillari-Amona and


Mahalaxmi-Amona tripped due to DPR operation. Now the Goa supply was fed through 220

kV Kolhapur-Ponda I whose jumper melt due to overloading at 17:10 Hrs due to high

loading leading to complete loss of supply to Goa.

Restoration:Initially the Power from SR was taken to supply power to VIP and Domestic

load. The restoration started with taking 220 kV Tillari-Amona at 17:38 Hrs and 220 kV

Kolhapur-Ponda II at 17:45 Hrs. Then After 220 kV Mahalaxmi-Ponda was taken back at

17:48 hrs. 400 kV Kolhapur-Mapusa II line was taken in service at 17:56 Hrs.

It was seen that after the tripping of 400 kV Kolhapur-Mapusa II, the loads at Tivim were

also fed from Ponda from only one available 220 kV Amona-Ponda line of Kolhapur side. As

total load of 250 MW fed from this line (made of Locust conductor) jumper at Ponda Gantry

got melted due to over-current/overload and resulted in loss of supply to Goa. However as

intimated by WRLDC via. Msg.No: WRLDC/MO-II/2012/7372 if the bus coupler at Amona

would have been in closed this situation could have been averted.

Goa : 13.11.2012

At 16:35 Hrs, due to tripping of 400 kV Kolhapur-Mapusa II Goa lost its supply from

Western region leading to a load loss of 200 MW. Earlier tothis event and 220 kV Amona-

Ponda I & II tripped on over voltage at 16:05 Hrs. At 16:05 Hrs: 220 kV Amona-Ponda I &

II tripped on over voltage and the same was not informed to RLDC. Also the Amona Bus

coupler was not closed. At 16:35 Hrs: The only available circuit to Goa i.e. 400 kV

Kolhapur-Mapusa II tripped on over voltage. This led to loss of supply to Goa from Western

region leading to complete loss of load of Goa which was being catered through WR system.

3 repeated attempts of restoration of 400 kV linesand 220 kV Lines got failed due to

continued Overvoltage in view of dropping demandon Diwali. Initially the power to domestic

load/VIP load were catered through SR grid from 17:10 Hrs. 220kv Amona-Ponda I & II got

restored at 18:10 hrs and 400kv Kolhapur - Mapusa Iat 18.15 hrs thus normalizing the full

WR network of the Goa by 18.20 hrs.

It was found that the 220 kV Amona-Ponda I & II tripped at 16:05 hrs but the same was not

intimated to SLDC. Also the bus coupler of Amona which should have been closed as per

Msg.No.WRLDC/MO-II/2012/7372 but same was not followed. If the Amona Bus Coupler

would have been closed after tripping of 220 kV lines the situation could have been averted.


The disturbance in Goa due to persisting high voltage problem has to be resolved as earliest

as possible. This incident being the third occurrence in the Goa leading to loss of supply to

Goa from Western region due to persisting high voltage problem at Karad, Kolhapur,

Sholapur and Mapusa in the recent months. There is a need to develop inter-tripping scheme

in Goa and also providing VAr support at these substation along with Ponda S/s.


ITEM NO. 3: Tripping of lines / ICTs:

The incidences of tripping of lines and ICTs during the period 01-07-2012 to 30-11-2012 are

enclosed at Annexure–3.

Committee may like to note/discuss.

ITEM NO. 4: Status of implementation in WR on Recommendations of Report on Grid disturbance on 30th and 31st July 2012

The Status of implementation in WR on Recommendations of Report on Grid disturbance on

30th and 31st July 2012 as on 31.12.2012 is given at Annexure-4.

ITEM NO. 5: Any other item

ITEM NO. 6: Date and Venue of the next meeting.

Detailed report on the occurrence on 10th Sept, 2012 at Korba East and Korba East Extension power station, Chhattisgarh: At 17:34 Hrs, due to heavy flashover in R –Phase LA of the 220 kV Korba (E)-Korba(W) I/C III while charging it through by-pass ,collapsing of wave trap of same phase of the feeder and snapping of the Jumper of 1P & 2P Bus of 220 kV Korba(E)-Korba(W) I/C I led to ground fault. The ground fault was sensed by all the generating unit and lines on Bus 1P and 2P as well as same was sensed by at 132 kV Korba(E) and Bango S/S. This led to tripping of all the lines and feeders at 220 kV Korba (E), 220 kV Korba (E)-Extn, 132 kV Korba (E) and 132 kV Bango S/S. The antecedent conditions (at 17:32 Hrs) to the incident are given under:- 1. NEW Grid Frequency: 50.010 Hz. 2. WR Demand Catered: 27209 (Approximately.) 3. Net Inter Regional Export: 2562 MW Constituent-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 17:32 Hrs:

WR Constituents

Demand(in MW)

Generation(in MW)

Thermal & Gas

Hydro Nuclear Wind Solar

Gujarat 7958 5231 407 - 828 77

Maharashtra 11969 6304 525 - N/A N/A

Madhya Pradesh

3896 1235 1260 - - -

Chhattisgarh 2246 1788 40 - - -

Goa 262 0 0 - - - DD 258 0 0 - - - DNH 620 0 0 - - - ISGS -- 9686 1234 1227 - -

Total 27209 24244 3466 1227 828 77

*As per WRLDC SCADA data. Power flow on major lines/ICT in the area (prior to the incident) at 17:32 Hrs: Sl. No. Name of the line/ICT Power Flow(in MW)*

1 220 kV Korba(E)-Siltara 125

2 220 kV Korba(E)-Korba(W) Interconnector I 40

3 220 kV Korba(E)-Korba(W) Interconnector III By-pass

4 220 kV Korba(E)- Raigarh 187

5 220 kV Korba(E)- Budhipadar III 82

6 220 kV Korba(E)- Budhipadar II Not in service

7 220 kV Korba(E)-DSPM -137

8 220 kV Korba(E)-Balco I -32

9 220 kV Korba(E)- Balco II -30

Annexure-2.1(ii)

10 20 MVA 220/66 kV Station X-mer I 0

11 20 MVA 220/66 kV Station X-mer II 0

12 160 MVA 220/132 kV Auto X-mer I 73

13 160 MVA 220/132 kV Auto X-mer II 80

14 132 kV Korba(E)-Jamanpalli 31

15 132 kV Korba(E)-Champa I 12

16 132 kV Korba(E)-Champa II 29

17 132 kV Korba(E)-Mopka I 7

18 132 kV Korba(E)-Mopka II 0

*As per WRLDC SCADA data. Generating Units’ status(prior to the incident) at 17:32 Hrs:

Sl. No. Name of the Generating Unit Installed

Capacity(MW) Actual Generation (in

MW) *

1 Korba (E) Unit-1 50 45






7 Balco CPP1-GT-3 67.5 0

8 Balco CPP1-GT-4 67.5 36.7

9 DSPM Unit-1 250 Out

10 DSPM Unit-2 250 145

11 Bango Unit-1 40 10



*As per WRLDC SCADA data. Event Overview: At 17:34Hrs The sequence of tripping and restoration at Korba (E) is given under as per the data retrieved from WRLDC SCADA and CSPTCL.

Sl No.

Name of the transmission element/ Unit Time of Tripping (hh:mm)

Relay indication

1 220 kV Korba(E)-Siltara 17:34 R-Phase Ground Fault , Zone-3

2 220 kV Korba(E)-Korba(W) Interconnector I 17:34

3 220 kV Korba(E)-Korba(W) Interconnector III 17:34

4 220 kV Korba(E)- Raigarh 17:34 Tripped from Raigarh end on O/C , E/F protection

5 220 kV Korba(E)- Budhipadar III 17:34 Tripped from Budhipadar end on

Zone II

6 220 kV Korba(E)-DSPM 17:34 Tripped from DSPM end on Zone 1

7 20 MVA 220/66 kV Station X-mer I 17:34 Transient Ground Fault

8 20 MVA 220/66 kV Station X-mer II 17:34 Hand tripped

9 160 MVA 220/132 kV Auto X-mer I 17:34 High Set Ground Fault

10 160 MVA 220/132 kV Auto X-mer II 17:34 No tripping

11 Korba (E) Unit-1 17:34 Generating Tr.Ground Fault,ULO

12 Korba (E) Unit-2 17:34 AVR Trip


14 Korba (E) Unit-4 17:34 AVR Trip



17 DSPM Unit-2 17:34 N/A

18 Bango Unit-1 17:34 N/A



21 132 kV Korba(E)-Jamanpalli 17:34 N/A

22 132 kV Korba(E)-Champa I 17:34 N/A

23 132 kV Korba(E)-Champa II 17:34 N/A

24 132 kV Korba(E)-Mopka I 17:34 N/A

25 132 kV Korba(E)-Mopka II 17:24 N/A

26 220 kV Korba(E)-Balco I 17:37 Tripped from Balco end on U/V,Directional O/C

27 220 kV Korba(E)- Balco II 17:37 Tripped from Balco end on U/V,Directional O/C

28 Balco CPP1-GT-4 17:37 Tripped on Islanding scheme obn U/V O/C stage II

*As per WRLDC SCADA and CSPTCL Load / Generation affected: The generation loss due to tripping Units was 560.7 MW (*As per WRLDC SCADA, CSPTCL and BALCO). Frequency Change : With the loss of generation ,frequency dipped by 0.30 Hz( i.e. from 49.98 Hz to 49.68Hz).The df/dt reported from B’wati PMU was - 0.053 Hz/sec. Restoration: At 17:55 Hrs partial station supply was restored from 33 kV feeders .After that 220 kV 2P Bus was charged from 220 kV Korba-Raigarh line and full station supply was restored. 220 kV 1P Bus was charged through 160 MVA Auto transformer I. With full restoration of 220 kV Bus at Korba (E), 220 kV Korba (E)-Balco-I & II was charged and Balco-CPP1-GT-4 got connected with grid. At 19:52 hours Korba (E) Unit 4 was synchronized with the grid. Then after Unit 1 and 5 was synchronized. During the restoration work, at 22:58 132 kV Champa-Banari I & II lines tripped on Over current protection from Champa end which led to insufficient evacuation path from Korba(E).Due to this Korba(E) system became unstable and wide fluctuation of frequency was observed(50 to 54 Hz).This led to tripping of all the feeders and 220 kV on Bus 1P of Korba(E).Again the restoration work started in the same manner. Analysis : The tripping details from korba(E) is still awaited as DR/EL files were unavailable.During the first time restoration tripping of 132 kV system on over current is clearly

due to generation and load mismatch.Thsi led to delayed restoration of the system.This may be due to lack of co-ordination between generators,transmission licensee and SLDC. Graphical plot:

Fig1 .Frequency and df/dt change during the disturbance

Fig2 . Change in Chattisgarh Demand During Occurrence

Fig3 . Change in Western Region demand During Occurrence Schematic Network Diagram:

Remarks: As per the IEGC Clause 5.2(r), SLDC CSPTCL should send information/data including disturbance recorder/sequential event recorder output to WRLDC within one week for purpose of analysis of any grid disturbance/event .The information received from SLDC CSPTCL is not in the format as well it is not complete which lead to delay in preparation of detailed analaysis. SLDC CSPTCL is requested to submit the detailed tripping report along with DR/EL output files for complete analysis of the any disturbance hence forward.

Also the restoration work should be carried out in a fashion to meet the demand and supply. Proper co-ordination between generators, transmission licensee, Discom and SLDC is necessary for restoration work. CSPTCL is also requested to send the list of coordinators from their side who are responsible for the disturbance analysis as this will help the WRLDC team for grid analysis.

Yours faithfully,

(Abhimanyu Gartia)

Dy. General Manager (MO-I & LO-I)

Detailed report on the occurrence on 11th September, 2012 at Korba-NTPC: At 00:05 Hrs, due to operation of LBB protection of Bus-III at Korba Generating station, all the elements connected with the bus become dead. This lead to tripping of Unit-5 and 7 at Korba NTPC and Unit 1 and 2 at BALCO. The antecedent conditions (at 00:00 Hrs) to the incident are given under:- 1. NEW Grid Frequency: 49.999 Hz. 2. WR Demand Catered: 26114 (Approximately.) 3. Net Inter Regional Export: 2383 MW Constituent-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 00:03 Hrs:

WR Constituents

Demand(in MW)

Generation(in MW)

Thermal & Gas


Gujarat 7195 5041 405 - 349 0


Madhya Pradesh

4540 1389 1629 - - -

Chhattisgarh 1942 1327 0 - - -

Goa 268 0 0 - - - DD 231 0 0 - - - DNH 605 0 0 - - - ISGS -- 9826 1225 1297 - -

Total 26114 23216 3635 1297 349 0


1 400 kV Korba-Vindhyachal II 242

2 400 kV Korba-Mahan-Vindhyachal 264

3 400 kV Korba-Bhilai I 376

4 400 kV Korba-Bhilai II 378

5 400 kV Korba-Korba(W) 30

6 400 kV Korba-Pathadi-Raipur -14

7 400 kV Korba-ACB-Bhatpara-Bhilai 409

8 400 kV Korba Balco -99

9 400 kV Korba-Raipur III 365

10 400 kV Korba Raipur IV 364

*As per WRLDC SCADA data.

Annexure-2.1(iii)

Generating Units’ status(prior to the incident) at 00:00 Hrs:



MW) *

1 Korba -1 200 210

2 Korba- 2 200 213

3 Korba -3 200 AOH

4 Korba -4 500 514

5 Korba- 5 500 512

6 Korba -6 500 515

7 Korba -7 500 496

8 Balco -1 67.5 50

9 Balco -2 67.5 49

*As per WRLDC SCADA and NTPC data. Event Overview: At 00:05 Hrs

• On Zone-1 distance protection, 400 kV Korba- Raipur IV line tripped on earth fault in R- phase. The fault was temporary in nature and auto reclosure operated successfully. But due to LBB-2 relay mal-operation occurred leading to LBB protection operation on Bus-III.

• With the LBB protection operation (A of Bus-III at Korba, all the connecting elements on this bus tripped.

The sequence of tripping and restoration at Korba-NTPC and BALCO is given under as per the data retrieved from WRLDC SCADA.

Sl No.

Name of the transmission element/ Unit

Time of Tripping

Time of Restoration (hh:mm)

Relay indication at Sending end

1 400 kV Korba Bus III 00:04:56:362 02:30 Bus Bar protection 2 400 kV Korba Raipur IV 00:04:56:383 Remains out Bus Bar protection

3 400 kV Korba-Bhatpara-Bhilai

00:04:56:861 04:31

Bus Bar protection

4 400 kV Korba Balco 00:04:56.313 03:07 Bus Bar protection

5 Tie Transformer II 00:04:55.434 N/A Bus Bar protection

6 Korba Unit-5 00:04:55:896 04:15 Bus Bar protection

7 Korba Unit-7 00:04:56.372 03:20 Bus Bar protection

8 Balco-1 00:04:56.400 07:15 Over-frequency 9 Balco-2 00:04:56.414 04:34 Over-frequency

*As per WRLDC SCADA ,NTPC DR/EL and BALCO Load / Generation affected: The generation loss due to tripping of Korba Unit 5 & 7 and BALCO Unit 1 & 2 was 1107 MW (*As per WRLDC SCADA). Frequency Change : With the loss of generation ,frequency dipped by 0.547 Hz (i.e. from 49.749 Hz to 49.202 Hz).The df/dt observed from Bhadrawti PMU was 0.0592 Hz/sec.

Frequency Response Characteristic :Western region FRC for the event is 751 MW/Hz and for NEW grid it is 1831 MW/Hz.(As per NLDC). Restoration: First the Bus-III at Korba was charged with the closing of Bus coupler-2 at 02:30 Hrs. After this 400kV Korba-Balco line was taken into service at 03:05 hrs and with that Balco unit 2 was synchronized with the grid at 04:34 Hrs. After that Korba unit 5 and Korba unit 7 synchronized with the grid. Balco unit 1 was synchronized with the grid at 07:15 Hrs. Analysis : The maloperation of LBB Numerical realy(Areva make,Model 821) led to the tripping of elements connected with the Bus-III. Graphical plot:

Fig1 .Frequency and df/dt change during the disturbance

Fig2 . Change in Western Region demand with Korba and BALCO Tripping

Schematic Network Diagram:

Remarks: The mal-operation of protection instrument is a serious threat when reliability of the system is considered. The operation of LBB at any generating station poses a serious threat to the security of the grid operation. So, there is a need to review the protection at all generating station which are having 500 MW and above generation capacity. The quality inspection of protection instrument and their upgradation is required by the generating station. (Abhimanyu Gartia)

Dy. General Manager (LO-I and MO-I)

Detailed report on the occurrence on 30th Oct, 2012 at 400kV Bhilai S/S, Chhattisgarh: At 12:23 Hrs on 30th Oct’12, due to failure of CVT/CB/LA of 220KV BSP-feeder I at 400/220KV Bhilai (Khedamara) Sub-station, 220 kV main bus tripped on bus bar protection. Due to this, all 220 kV feeders emanating from Bhilai (Khedamara) tripped along with 400/220 kV ICT I, II and III. 400 kV Bhilai – Seoni S/C and 400 KV Bhilai – Bhadrawati S/C also tripped simultaneously. 220 kV S/s Bhilai, Thelkadih, Gurur ,Barsoor and 132 kV S/s of Bhilai, Ruabandha, Kurud, Rajnandgaon, Dongorgaon, Gunderdhehi, Balod, Dallirajhara, kanker, Jagdalpur and Dongorgarh were affected due to the occurrence. The antecedent conditions (at 12:20 Hrs) to the incident are given under:- 1. NEW Grid Frequency: 49.971 Hz. 2. WR Demand Catered: 33695 MW (Approximately.) 3. Net Inter Regional Export: 1727MW Constituent-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 12:20 Hrs:

WR Constituents

Demand(in MW)

Generation(in MW)

Thermal & Gas


Gujarat 10960 8502 203 - 230 447


Madhya Pradesh

5304 1823 580 - - -

Chhattisgarh 2226 1917 40 - - -

Goa 344 0 0 - - - DD 252 0 0 - - - DNH 580 0 0 - - - ISGS -- 11519 245 1459 - -

Total 33695 31299 1987 1459 230 447 *As per WRLDC SCADA data. Power flow on major lines/ICT in the area (prior to the incident) at 12:20 Hrs: Sl. No. Name of the line/ICT Power Flow(in MW)*

1 400 kV Bhilai-Raipur -445

2 400 kV Bhilai-Bhadrawati 467

3 400 kV Bhilai-Koradi 541

4 400 kV Bhilai-Seoni 432

5 400 kV Bhilai-Bhatapara -235

6 400 kV Bhilai-Korba- I -361

7 400 kV Bhilai-korba- II -362

8 400 kV Bhilai-Korba(W) -357

9 400/220 kV Bhilai ICT- I 95

Annexure-2.1(iv)

10 400/220 kV Bhilai ICT- II 95

11 400/220 kV Bhilai ICT- III 97

12 220 kV Bhilai-BSP I (Khedamara ) -2

13 220 kV Bhilai –BSP II (Khedamara ) -2

14 220 kV Bhilai-Raipur (Khedamara ) -74

15 220 kV Bhilai-Urla (Khedamara ) 23

16 220 kV-Bhilai-Bemetara (Khedamara ) -44

17 220 kV Bhilai- Thelkadih (Khedamara ) 95

18 220 kV Bhilai-BRSS-I (Khedamara ) 133

19 220 kV Bhilai-BRSS-II (Khedamara ) 137

20 220 kV Bhilai-Raipur (Bhilai) -122

21 220 kV Bhilai-Siltara (Bhilai) -29

22 220 kV Bhilai-Gurur I (Bhilai) 68

23 220 kV Bhilai-Gurur II (Bhilai) 66

*As per WRLDC SCADA data. (export +ve ,import -ve) Event Overview: Due to CVT Blast of 220 kV BSP-Bhilai II Bus-Bar protection operated at 220 kV Bhilai (Khedamara) S/s. This resulted in tripping of all the 220 kV feeders from Bhilai (Khedamara) S/s. The sequence of tripping and restoration at Korba (E) is given under as per the data retrieved from WRLDC SCADA and CSPTCL-SLDC:

Sl No

Name of the Transmission

Element

Time of Tripping (hh:mm)

Time of Restoration

(hh:mm)

Indication Remark

Local End Remote End

1 220 KV Bhilai (Khedamara) - BSP 1

12.23 15.58 hrs on

03/11/12 Zone-1 Trip Zone-2

Failure of c-ph CVTof BSP-1.A-pole tripped in 2.5 cycle. B-pole tripped in 10-cycle. C-pole tripped in 6 cycle after 6 cycle -fault in CB was created

2 220 KV Bhilai (Khedamara)- Raipur

12.23 17.09 Zone-1 Trip Zone-1 Trip Also Tripped

3 220 KV Bhilai (Khedamara)-Bemetara

12.23 13.10 Zone-4 Zone-2 Trip Also Tripped

4 400 KV ICT- I At Bhilai(Khedamara)

12.23 13.14 O/C - Also Tripped from 400KV side on bus bar Protn.

5 400 KV ICT- II At Bhilai(Khedamara)

12.23 13.18 O/C -

6 220 KV Bhilai (Khedamara)-Thelkadih

12.23 13.11 Zone-4 Zone-2 Trip Also Tripped

7 220 KV Bhilai (Khedamara) -BRSS -1

12.23 13.17 Busbar

Prot.Optd. Zone-2 Trip

Fault was correctly cleared from Bhilai end in zone-2operation of the relay

8 220 KV Bhilai(Khedamara)-Urla

12.23 13.25 Busbar

Prot.Optd Zone-2 Trip

Busbar prot.opration on S,U indication .

9 220 KV Bhilai (Khedamara)-BSP-2

12.23 15.54 Busbar


Load / Generation affected: The load loss due to tripping distribution lines was 508 MW (*As per CSPTCL-SLDC). The energy loss was 0.59 MU during the occurrence. Frequency Change : With the loss of load as above, frequency increased by 0.234 ( i.e. from 49.999 Hz to 50.233 Hz). Restoration: Restoration work started with taking 220 kV Bhilai-Raipur in service and Bhilai bus was charged. Then 220/132 kV ICT-II was taken in to service at 12:59 Hrs and 132 kV Bhilai Bus was charged. Then one by one other lines were taken in to service and loads were restored.

10 220 kV Bhilai (Khedamara)-BRSS-2

12.23 14.13 Busbar


Fault was correctly cleared from Bhilai end in zone-2 operation of the relay

11 400 kV ICT- III At Bhilai(Khedamara)

12.23 13.42 hrs on

05/11/12 Busbar

Prot.Optd -

Tripped from both Ends on Busbar protn.

12 400 kV Bhilai(Khedamara)- Seoni

12.23 16.07 O/V Trip - Over voltage trip

13 220 kV Bhilai - Bhilai(Khedamara) 1

12.23 13.17 Zone-2 Trip Busbar Prot.Optd

Fault was correctly cleared from bhilai end in zone-2 operation of the relay

14 220 kV Bhilai - Bhilai(Khedamara) 2

12.23 14.15 Zone-2 Trip Busbar Prot.Optd

15 220 kV Bhilai - Raipur 12.23 12.57 - Zone 2/3/e-Fault Trip,B- phase

Hand trip

16 220 kV Bhilai - Siltara 12.23 12:36 hrs on

31/10/12 Zone-1 Trip , O/C

Zone -1 Trip Failure of BSP CVT (Total interruption)

17 220 kV ICT-1 At Bhilai 12.23 13.19

Since all sources Siltara, Raipur, Khedamara 1 &2 were tripped by 12.23 then high voltage supply to Gurur & Barsoor S/s automatically interrupted. Later on all feeder/Xmers were Hand trip

18 220 kV ICT-2 At Bhilai 12.23 12.59

19 220 kV ICT-3 At Bhilai 12.23 13.39

20 220 kV ICT-4 At Bhilai 12.23 13.41

21 220 kV ICT-5 At Bhilai 12.23 17:40 hrs on

03/11/12

22 220 kV Bhilai - Gurur 1

12.23 13.02

23 221 kV Bhilai - Gurur 2

12.23 13.49

24 132 kV Bhilai - Rajnandgaon

12.23 13.18

Interruptions occurred to all 132 KV feeder

25 132 kV Bhilai - Raipur 12.23 13.43

26 132 kV Bhilai-Dhamdha

12.23 14.27

27 132 kV Bhilai - Raipur 12.23 13.43

28 132 KV Bhilai - Acc 12.23 15.01

29 132 KV Bhilai -Simga 12.23 14.46

30 132 KV Bhilai-Sector C 12.23 13.51

Graphical plot:

Fig1 .Frequency and df/dt change during the disturbance (several spike in df/dt reveal tripping

of several lines in Chattisgarh system) Schematic Network Diagram:

(Source: CSPTCL-SLDC)

Remarks: The bus fault is very severe to the system and may lead to cascade tripping. So, the practice should be to carry out the diagnostic test of equipments regularly and maintenance schedule may be followed strictly.

Yours faithfully,

(Abhimanyu Gartia)


Annexure‐2.1(v)

Detailed Report on the occurrence dtd 14th Sep’ 12 at Jindal Power Ltd. Tamnar, Raigarh

On dated 14th Sept’ 12 at 19:15 Hrs both 400KV JPL (Tamnar) – Raipur Line 1&2 tripped on Direct trip command received from Raipur end. Which lead to tripping of all running 03 Units of 250MW (one unit no. 2 was under AOH). The tripping of all units and lines resulted in Black‐out in O.P. Jindal Thermal Power Plant. In detailed analysis, it is found that direct trip command received at JPL due to hand trip operation at Raipur end for both the lines and message was received from POSOCO vide fax no. LD/9/1176 dtd. 14.09.2012 that opening of 400 KV JPL – Raipur lines from Raipur end due to an occurrence at Sipat Generating Station. The other details and restoration time as below.

Load on Generator and Lines prior to the incident at 19:00 hrs

Sl. No. Name of Line/ICT Load flow 1 400KV Raipur Tamnar Line ‐1 344 MW 2 400KV Raipur Tamnar Line ‐2 343 MW 3 250 MW Unit‐1 252 MW 4 250 MW Unit‐3 248 MW 5 250 MW Unit‐4 256 MW 6 250 MW Unit‐2 Under Annual Overhauling

The sequence of tripping and restoration at JPL, Tamnar is given under as per the data.

Sl.No. Name of transmission element/Units

Time of tripping(hh:mm:ss)

Time of Restoration(hh:mm:ss)

Relay indicating

1 400KV Raipur‐Tamnar Line 1

19:15 19:40 Direct trip received

2 400KV Raipur‐Tamnar Line‐2

19:15 02:45 Direct trip received

3 Unit 1 19:15 00:25 Over frequency due to Load throw ‐off

4 Unit 3 19:15 22:32 5 Unit 4 19:15 02:35

Load / Generation affected: ‐ The generation loss due to tripping of JPL Unit was 756 MW

Restoration: 400KV Raipur Tamnar line ‐1 was charged at 19:40 hrs. After that at 22:32 hrs Unit 3 was synchronised, at 00:25 hrs unit ‐1 was synchronised and at 02:35 hrs Unit ‐4 was synchronised. In last after getting charging code from WRLDC, 400KV Raipur Tamnar Line‐2 was charged at 02:45 hrs.

R K Shrivastava Naresh Punjabi

AGM(Swyd) Sr GM(Electrical)

Detailed report on the occurrence on 3oth July, 2012 at CGPL Mundra power station Guiarat: At 06:06 Hrs, due to tripping of 400 kV CGPL- Limbdi-ll on Y-B Phase fault, 220 kV Network from Bhachau also got tri(lped on over current which led to separation of CGPL Units alorlg with Bhachau load from the rest of the grid. Earlier to the event, 400 kV CGPL-Limbdi-l was oct due to R Phase to earth fault and 400 kV Bhachau - Ranchorpura I & II tripped at 06:04 hrs on Y phase to earth fault . With separation of CGPL from the grid, Unit 20 immediately tripped wh~le unit 10 operated with Bhachau loads for 50 Min. 400 kV Bhachau-Ranchorpura II was charged at 06:57 HI-s but it tripped on Y phase to earth fault at 06:58 Hrs causing power swing and ed to tripping of 'Jnit 10.

The antecedent condition:; (at 06:06 Hrs) to the incident are given under:-

1. NEW Grid Frequency: 50.1 67 Hz. 2. WR Demand Catered: 27546 MW (Approximately.) 3. Net Inter Regional Export: 1817 MW

Constituer~t-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 06:06 Hts:

- - - ~ -- -- ~ ~ - - - Generation(in MW)

WR Demand(in ' ~- ~ -~ - ~

Constituents M\N) ; Gas Hydro Nuclear I Wind Solar I Thermal &

-- ~-~ ~ ~~ -~~ - - - -~ -- - - -~ ~ u k r z t 10331 6655 1 5 5 1590~ 0 -, ~- - ~~~ ~~ ~~- -~

Maharashtra 10536 i 6032

Pradesh I I

-- ~ ~~. ~- ~ -- ~ .- ~- ~-. - -~ -- -

Chhattisgarh , 2446 1994 ! 0 - ~ ~ ~~. -~ - ~.~ ~ -~ ~ -- -. - -~

Goa 223 ! 0 I 0 ~- -- ~ ~ -~ -- ~~~ -- -~ .- -- - .- --

DD 22'2 0 0 - ~~ --- - -- ~ -- - --

DNH 57 5 I 0 1 0 I -- ~~ -~ - -~ - ~ - -~ - . -~~ - - ~- -~ ~.-. - -

ISGS 1 9361 : 32 1302 ~ -- -~ ~~ ~~- ~ ~ ~ ~ - ~ . ~

- ~ -

Total -- ~- - ~

27546 25603 868 1302 159f~ 5 - -~ ~ - ~-~ ~ -~ --- ~ ~ - ~~ ~- - - -- -- - - -.

-;a lp; ',l\'E icic .sC,b.131,* dzta ,

~- - - - - , - - _ - ~ -.__---__ _ - -~ ~

- - -- , . .- . . A - - s :.!- - ..,. & rr -- . - . . , I. r - 7 . I ..

- , . .... , .L.i..~." . d b . I S - b ! l h l 7 ' l \ - , ! ~ " ~ L G L i L U ~ L , , ~ , u + # > b

- -~ -~ -- --- -- .- -- ~- -~ ~~~- - -- - -- - A - , ,, -. <;, I.;'.,! c4.t--;;! - ' i.--i- -:. - ,- .

, . I , ~ , ,

. , . _ - . - - 1 , , , , . .%. 1 1 ,z,z, iL2 ;; ;; ;:;,&51; LC) (;;lI;UI-," lUUl, ~ -~

, - --

,J

- - - , - ~ ; 3 9 I;',! CG?L- Lin?bC:j i ! i~ q7? L

-- - -

4 L L L ~ k\! (CIG?i- 3 h ~ ~ h z ~ : I! I I

44.4 - - ~~ -- . -- - -- -

As per VV'RLDC SCAUA d3tz and CGPL. 1

Annexure-2.2(i)

Generating Units' status(prior t o the incident) at 06:06 Hrs:

SI. No. Name of the Generating Unit Installed Actual Generation ( in 1 Capacity(MW) MW) *

- -- ~ -- ~- -- -. -- - -- -

1 ) CG3L Unit-1 0 800 1 614 (NC) i I

~ --.----.ppppp----p -- --- -

2 CG3L Unit-20 800 614 (NC) - - -- - - - - -- - -- - - 1 - - 1 . - - - : *As per WFILDC SCADA data and CGPL. Units were running at 1228 MW.

Event Overview and Res.toration: 40C kV CGPL-Lim2di I and I1 were continuously tripping due to line to ground fault \vhich was reasoned out to be due to flashover of insulators. At 05:26 Hrs 400 kV CGPL-Limbdi I got tripped again on R-Phase to ground fault nad was not taken in stmice due to persisting fault. At 05:45 Hrs 400 kV CGPL-Limbdi li got tripped on B-Phase to ground fault ana was taken in service at 06:02 Hrs.

0 At 06:04 Hrs 400 kV Bhachau-Ranchorpura I & I I tripped on Y Phase to ground fault and the generation at C:GPL was reduced to supply Bhachau ICT and 400 kV L~mbdi line I I .

At 06:08 Hrs: 400 kV CGPL-Lim13d1 II got tripped due to Y-B Phase fault. This led to tripping of 2;!0 kV lines from Bhacha-r due to over loading and Unit 20 got tripped wh~le U n ~ t 10 came on Bhzchau Load.

The sequence of tripping and restoration at CGPL is given under as per the data i-eti-ieved from WRLDC - - SCADA. - - - - -

Si. ( Name of the tr:.nsmission Time of Tripping ) element/ Unit I Ihh:rnrn) I Relay Indication

No. / .~ I - - _-

I 1 400 kV Bhachau-Rarichorpura I 8 I I ) 06:04 1 -- Y Phase-Ground Fault - - -- -

2 I 400 kV ~ ~ ~ ~ r n b d i I I .- - . - -- 06:08 1 - Y-B Phase Fault -- - --- 3 I Unit 20 . - . . - --.~- Reverse Power Protection 4 1 Unit 10 06:58 Reverse Power Protection 1

4 *As per WRLDC SCADA and CGPL

Load ! Ger:erstion affected: The generation loss d ~ ! e to tripping of CGPL Ynit 10 znd 2C \:\:ss .I 22g c\/ylri ( . n . ~ per v ~ ? . L D ( ; ~r..r."!

- . - , . . . . A - - 8 - -- r - I I . -- ,,- - L I - , , , . - ,L ,L , - , , . z L ; - , , ! ,,, c 2 i7 - , .!!; ,-!m?.y,! ,-,!-s r,.,, - b ~ - - ~ ; m - - , , - , , - , , , , - ,/ ,-.., - 1 7 ' , , , r'i---L--,, , - , , - . , > , , L t , E...- . , . - , , , - I - . , , t w , , , - , . , . < - - - - - - - . I- - - j ! 1rno rrnm Gh-,l--*. - - - I . , , ,, , , ,,, , ,, ,,,, ,Gu G , bc! .Ths i i i-,;~ 501 il-inrni 3 1 d t J - 5 / 3hase io ~ r ~ t i n d fault ~ i - 1 ~ : 7 l - l ~ " 1-1 1 - ' L I I ! ' I 1-1

- . -,.., - - .. ^ I - - - - ,uvvGI ~ G ~ ; ~ I ~ I c c d i i - ~ ~ ;i, /is ii-lppii-19 on reverse power proiecrion .This leci to loss of - $ * , , - ? m \ , - . & - , . - - 3 . , -J. - - f - l ;.vl,Ll,,a,u Jurrl:, . 3 ~ be!-L. .&.i G7:% Firs swiicngears were chsrged via 220 k'J ldznikt-iakar ~u~:,~:,~)I 2pld ~t < o , ? 3 \+rs 4129 k\L; ~ ~ ~ < ~ ~ ~ ! : ~ ~ ~ ~ <,,;z; c>,zrs~$, p,i-~di-~d qs:qQ kiis ul- l i i ,:,,el-s ready in ,-allin3 c c ~ c i t i ~ i i biit dcie i~ higher eccentricity o i shait it was sliutdo\vn for iuriher icvestig 8 t' 1'3n.

Graphical plot:

I--

.L r . -

F r e q ~ ~ e n r y d r o p p e d f r o m 4 5 . 9 7 t o A - - - . - 49.09 d u e t u s e p a t e a t i o n o: C3PL

ft o n l i e s t of t h t g r i d .

2: 3 -.

Fig1 .Frequency and dfldt during the disturbance

Schematic Network Diagram: 7 -

- - -- Lerd3 Schematic Network Diagram

I -- . - - - . --

C? I-, a 7-1 . . LEG E N D

7 : . , - .-~, , , + . " ST:

';~fic~qy vjlqy &T.T~+?J~ GmtRlW~nf i~

~ $ S ~ T T fclfi~2.3 Kakrapar Atomic Power Station rn wfrr~n mm, f a1 f h 3'34651

[ ~ i ' a i i ' T G V T @J 3 ~ s ) PO AIUUUALA DISI S u r t * PI? 1.926::

1 C2626-2111233. 234i.:4 1 ,'31233 h: E f l <3-' O k e 92626.251221 NUCLEAR POWER CORPORATION ,,,? OhER

OF INDIA LIMITED ki F ~ X '12626-23.266 2 3 2 6 s

( A G o v e r n n1c17t o f 1 1 7 ~ i i u E n t e r p r i s e )

No.KAI'S/BMS/EMU/ 73 Date: 1 3-08-2Cl 12

To

f 4 , y ) Shri S. D. Taksande,Meinber Secretary q. b. *. lp,mC

L%'I<PC. F - 3. MIIIC Area, (. ', / - q ~ / \ n w n d ~ Q ' / 1 0, Marol. Andheri (E,) _ )

?L %F / ~ ~ t @ ' 7 I < / ' ? ( , MLIMAAI - 400093

> ' Sir.

1 . 'Vame of statior,: 2 x 220MW Kakrapar Atomic Power Station.

2. Yame of feeder / equipment: 2 20 KV Bus bar # 2

3. Date and time clf occ~lrrence: 12.06.2012 at 19.47 hrs

4. Date and time clf restoration: 16.06.20 12 at 16.10 hrs

5 . Pripping at local end with XTF reading, if any. No change in reading

trip and lock out (.4N -- 624) - - - -- - -- .

trip and loch out (AN - 61 7) VAPI # 2)

-- i lock out ( A N - h I ? ) 1

\/ A.V # 3) -- - - - - -- .- - - - - -

loch OLH ( A N - 602) 1

HAL # 2) 1

Circuit Details --

220 KV Bus bar # 2

6. l'ripping at reir otc cnds with XTF reading, No change i l l reading

Wiildow in dicatioil 1 . Bus bar differential protectioil operated (AN - 636) 2. Bus differential chcck o~era ted (AN - 6371

7. Tripping detail:;: On 12/06/213 12 at 19.47 hrs. 220 KV bus bar # 2 tripped on bus bar differential protection. Switchyard survey was carried out just after the incident. At the extreme end (1 3'" Bay) of the 220 KV main Bus-11, a section of the R - phase Bus

Annexure-2.2(ii)

bar was found bent. Bus post insulator was found in snapped condilion ne3r R. phase Bus post insulator structure and its base part was still intact on structurc. Some of the broken insulator pieces were found lying on the ground near support structure, and on visual examinations these were giving the itnpression of freshl) broken porcelain. Further visual examinations of sheared BPI base indicated that 40 '4 area was appears to be fresh one and remaining 60% aiea having dull appearance giving impression of existence of internal crack since long period.

8. Analysis of occurrence:

Internal crack night be existed in insulator base area which could not be detected during routine inspections and probably due to heavy wind fi~rce it has causcd insulator shearing off froin its base

9. Restoration of supply :

1 ) 5 14- Line - 3 (KAPS- VAPI # 2) charge on 12/06/20 12 2) 5 14- Line - 5 (KAPS- VAV # 2) charge on 12/06/2012 3) 5 14- Line - 7 (KAPS- HAD # 2) charge on 14/06/2012 4) 521 - SUT - 1 norinalization on 12/06/2012 5 ) 220K\' E3cs bar i? 2 n=:-ma!izatisn or, ! 5.05.2012 at ! 5. ! 0 hrs

Regards

Sincere11 yours,

Detailed report on the occurrence on 3oth June, 2012 at APL, Mundra - Guiarat:

At 01:22 Hrs, due to tripping of APL-Sami-Degham circuit-l on Zone 1 distance protection, Stage II of SPS at Adani operated leading to tripping of Unit 4.The tripping of one line led to overloading of APL-Sarni-Degham II which resulted in tripping of Unit -5 due to operation of Stage Ill of SPS at Adani.

The antecedent conditions (at 01:20 Hrs) to the incident are given under:-

1. NEW Grid Frequency: 49.457Hz. 2. WR Demand Catered: 30290 (Approximately.) 3. Net Inter Regional Export: 3357 MW

Constituent-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 01:20 IHrs:

i I WR

Generation(in MW) ' Dernand(in I

- --r ----: 1 Constituents 1 MW) r ~ z ~ r y ~ ~ Wind Solar i

I Pradesh b ~ h h ~ ~ ~ h t p 2386 - 1

L---- A-----

Total 7 3 0 2 9 0 7 3 0 4 3 7 7 --L--- 1322 ~ 3 3 8 r 5 5 6 1 0 i - -- ---A

* A s p e r ~ m ~m, data.

Power flow on major Ii~nesllCT in the area (prior to the incident) at 01:20 Hrs:

m 6 ( Name of the IinellCT Power Flow(in MW)* -1 - - - s a m i - Degham I

400 kV APL-Sami- Degham II F P ~ k - ~arsana

1 4001220 kV ICT Ill 1 0

465 7 463 - 426 I

400 kV APL- Hadala

-- 4001220 kV ICT I 4001220 kV ICT II

*As per VJRLDC SCADP, data.

- 386 I -7 60

60 4

Annexure-2.2(iii)

Generating Units' status(prior to the incident) at 01:20 Hrs:

Installed F N c F h e Generating Unit Capacity(MW) Actual Generation (in MW) *

.4PL Unit 4

Event Overview:

L 3 1 APL unit 5

At 01:22 Hrs On Zone-I distance protection, 400 kV APL-Sami-Degham I lines tripped. VVith the tripping of this line, the 400 kV APL-Sami l l get overloaded (806 MW). Due to overloading of 400 kV APL-Sami-Degham-ll, stage II and Ill of SPS at Adani operated. With the operation of stage II of SPS at Adani, Unit-4 (which was on selection) tripped. Similarly with operation of stage Ill of SPS, Unit-5 tripped.

330

330

The sequence of trippir~g and restoration at APL is given under as per the data retrieved from WRLDC SCADA.

306

208

--

*As WWRLDC SCAD14 data. I 660 488

Name of the tri~nsmission element/ Unit

I

APL Unit 5 1 01:22:10 1 12:53 SPS p~

*As per APL

1

Load I Generation affected: The generation loss due to tripping of APL Unit 4 and 5 was 696 MW (*As per WRLDC SCADA).

Time of Tripping

Frequency Change : With the loss of generation ,frequency dipped by 0.41 Hz( i.e. frorn 49.52 hz to 49.10 Hz).The dfldt reported from Raipur PMU was - 0.038 Hdsec.

(hh:mm:ss) 01 :22: 10 01:22:10

Time of Restoration

FSC was taken into :;ervie at 02:28 Hrs. With the restoration of both lines ,Unit-5 was synchronized at 12:53 tirs and Unit-4 at 14:16 Hrs.

Relay indication at end

(hh:mm) 02: 12 14:16

Restoration:

Analysis : As informed due to the foggy weather there are continuous tripping in the coastal area of gujrat due to flashover creating faults.These lines tripped several times on the same day within few hours as shown in the above table is very serious as per grid reliability is concerend.The tripping of units has lead to dfldt of -0.038 Hdsec which pose as a threat and

Zone-I distance SPS

Name of the t~ransmission element

400 kV APL-Sami- Degham I 400 kV APL-Sami- Degham I

Charged

02:12 Already in

Service

Tripped

03:58 04:49

Charged

05:57 06:05

Tripped

06:22 06:23

Charged 1 -- 08:36 08:17 1

frequency drop of 0.41 Iiz.The availability of these lines is of prime concern as the tripping of units are affecting the whole grid as can be seen from the demand curve of WR. Graphical plot:

J .- - 3 6

3 ::

29 5

3 : 2 Frequency dropped by 0.41 Hz(Frorn 49.52 t o 49.10Hz)

3 : -

Fig1 .Frequency change during the disturbance

5 3 : 3 5 3 3

- 3 6 I 3 i 3 3

4 9 . 6

29 2

- 2 1" :333; E. 2 :: E Y Gujrat demand dropped

G r 3 from 9967 MW to 9680 M W i -

-Frequency 2 5 6

-Gujrat Demand

- 5 . 5

2 s -

2 s 1 ... 5'33

~ ~ U ? s 6 8 8 3 8 $ S 8 8 8 8 $ 8 8 8 8 8 8 S : 8 8 8 g ~ 8 8 8 8 8 8 8 8 E 8 ~ 8 8 e ~ % S 8 8 X ~ ! = @ m 8 S ~ ~ R ~ ~ ! F . ! % " , @ ~ ~ ~ ~ ~ ~ ~ ~ ~ $ ~ ~ 8 ~ 8 i ; 8 " c C 8

8 S 8 S E 8 g g g : 3 g 8 ~ 6 6 6 S 6 ~ i ; ~ 6 S 6 ~ o ~ o O c o o c o o ~ 6 ~ g ~ ~ ~

Fig2 . Change in Gujrat demand with APL Units tripping

F r e q u e n c y

- W R D m m a n d

\ WR demand dropped f rom 30170 MW t o 2 9 7 0 7 MW

- - - - - - - - - - -

Fig3 . Change in Western Region demand with APL Units tripping


APL400 kV Switchyard I

330 M W Unit 3 400/220 kV ICT I t

330 M W Uni t4

660 M W Unit5

660 MVI, Unit 6

Sectionalizer

Detailed report on the occurrence on 2gth June, 20?2 a t Amarkantak TPS - liliadhya Praciesh:

At 25 32 t>rs on 28'' June, 2012 ihere was an occurrer~ce at Amat-kantak TPS gerlerating station and 220,'132 kV Amarka~tak S/S due to CVT i3urst in R Phase of :ne Traction feecer no 1 D u g to b~: rs t i t i t~ of CVT . its f ia~ne ciirectly created the bus fault. Due to this the 220 I :V bus a i d 122 k V bus at Aniarkantak Si/s became dezd This led to tripping of all the lines froin these buses With the tripping of e v a x a t ~ o n lines froin Ainarkantak SiS. HTPS unit 3(1201dLr\i) 4(11/Ot14V~l) and 5(27 0fdiW) got tripped.

- 1

I ne antzcecient conciitio:is (at 23.30 hrs) to the incident are given under:-

1 NEVLI (;rid Frequency. 48.97 Hz. 2 Wl? Ds.rnand Cat2red 31 298 MW (App:oximately.) 3 Net Inisr Fiegionsl Ex i~or t : 2764 MW

Constituent-wise generation and demand detaiis prior to the event (As per \fi,fRLDC SCADA cizta) at 23:30 hrs:

- -- ~-~ . -- -- - - ~ . --- - .- . ~ . !

WR ..... .......... Generation(in MVd)

............ ............. Demand(in - -

Consti t ~ e n t s IEW) Hydro Nuclear Wind Sofar I Thennal & ! Gas

... ~- -. .... .......... . .. . ... ..-....

75 -

Su.'arzt 10343 , 9152 -- 55 0 ~ ~ ~ ~- -~ -- - ~-~ - ~~ .

ld/laharai;i-~tra 13085 7349 726 - - l JiA !'.J ,/A .........-.. ........ .-.............. . . ........... .... - .. . . . . . . .

Madhya 5099 21 32 81 1 - - -- -- Pradesi-I ~- .

..-........ .......-..................... . . . ........... ..-... T ~ - - -

Chnatiisgarh 267 2 1885 1 0 - - - - -- ...........- - ... ......... .... -- . .............. ..... -~ ...-.... ..

223 Goa 0 0 -- -- - - . . . . ....... -...... . ................................

DD 243 0 0 - - -- -- .. -~ .......... . . . ......... -----,- ........ ............. -- . ..........

CrdH 523 0 - - - - - - I 0 ..... ...... . .. . ... . ...........-. -~ ........ ..........

ISGS --- 12598 : 4 2 ; dai3 -- -- 5 ",= ...-... ... . . . . ...... --p--p-,---..---. ......... .... ..

-I-,.> - ' .?"? , " - c --,.,- i J .Z / ;, I ~ Y O 3377 6 i 654 1.330 6 5 3

...................... .-.. .-. ... ... . . - ...... - ......

Annexure-2.3(i)

~ - - -- - -~ - - -.

i 1 22iii6.E ic\/ ICT I N ~ ~ - C u r ~ e n t - ~ ........... ..

22016.5 kV ICT I 2201132 kV ICT I -24

. . . . . . - . . . . ----- ~- ...... . . ..- - . ...... -- --

14 I 2201: 32 kV ICT 1 I -31 . ..... ..... . ... . -~ . . . . . . . -

15 132 k'J Arnzrkantak Shahdol 34 ........ ................ - - . . . ........ L . - . . - -- - - .

1 E 132 k\/ Amxkantak K o i n ~ a 2 1 - ... .... ...... . ..... .... ......-..... -- ~

17 I 132 k\f Arnarka~tak R2jmilar-i I 1 0 ...... . . . ...-. ... . ........... ...... ~- ~ ~ ~-

18 132 kV Arnarkantak Raimilan l l , -35

'As per- iYR iDC SCADt4 dara

Gerieiai:ng Units' s t a t ~ s j ~ ; i o r to the i~c iden t ) zit 23:30 h r s :

1 lnstslled Actual Generatio2~ (in S1. Pic. Neme of the Generatjfig Unit

i Capaciwlb\l) v .. . L.2 . ' .--...-... ....................... .- ---

I 120 1 ~ i4TPS Unii-3 i : Ei 1 ~- ... . . ....... . .... .......... . ......

2 1 ATPS U ~ i t - 4 ~ 120 13 3 ..... . . . . .. ....... - ................... .................

3 1 , i i P S U~nit-5 21 0 163 ...... ~- ------.-p----...--..----.-. ......... ..... -................. - - . ............

'As aer 'NRLDC SCAD 4 data

A: 23:32 Hrs P D i ~ e to bur;ting o";-Pilase CVT of 220 kV Amsr-kantsk-Tractior I at -ir:ia:kar-iral.. S/s

r x r e W ~ S fii.2 \JI~ICSE fianie directly created the bus facl t T h ~ s led 10 k i p ~ i n g of aIi the 223 i c ' J Sus gcd s / \ ti;? \,i-,zs cn 132 ,:\/ LL; i , c ~ ~ c ~ . ~ I-.,--.-' 1 7 7 1 4 - < \ ; l ,y,a,- i ;~--- ' 2 ) : L - : I ~

. . :S.;-ial-,dc;l a,:d c ? , i ~ ; ~ r k a ! : t a k - E ~ j ~ ~ ~ I ~ n - I I j .

7 . ;31c!l- I, , I I ; r & - ~ ? ~ ~ : ~ ~ ~ s:(jt;y;or; .. ............ . . . . -~ ~ .. - . . - . -~

,- -. c; :dl',,! A,r?) -<I !.!(~ 2 r: :;? i/. - 7 .. ::,I I GG.35 ; +;?;>(j t < l p ; ~ ~ : : - 73 - ni5:;l~c? 3 1 i l i h ~ I > . _ a , , . .L.

r t v p , : :-;,r n I ,-, - \ d, \ , i : - ' a . ........ ~p ----- . . . .. ...... -- .. .. .

c 2213' %V T-acticr I ?:..? i ?:.;1 ! - . . 3 - t DPR Optd

...-......- - - - .....-.-- - . -. ...... - .......... -............ ~ .- ---- ...---

8 22Ci6.6 iCT I " 7 -- .JL T 2 3 : 5 6 U/V pro';scti~n . . . . ............ ~ ......... ~ . * - - ...-...--. ~ - I T - 7 5 Z2OIE 6 ICT I I - 3 : . 1~ 23.56 ! UrfV Protection

.- ....

' 3 - S, 1' 05:IO MFT

I 1 I

. . I operated - - - - - - - - -- . . - - - - -- - - .

1 1 P,TPS Unit-4 1 I ? 1 08:17 UIV Prot5ction ~ ~

~

12 ;ATPS unit-3 1 3;:32 t

1 9 2 2 i UiV Proiecton , .. -...... ..... ........ . +.- .. .............

1 3 I 2 2 k\J Amarkaniak 33.40 1 00:21 i ': blotma I

I

. . . - - . . . . I I

--. .

14 ,I C'2 i < ~ h,mar.kaniak- 1 33:4!'1 1

i _ ' +

16 1 :,2!33 k\/ ICT l l 4 1 00:17 1 . - -.... _ . 1 ....................... _ - ..... ,

17 132133 k\JICT Ill 2?:4o 1 00:36 -

18 2;iO k\/ Trac:ion II : 2 I i > ? . < - ; ,...- i Hend Tripped No trlF~r.!r,g - - - - - -- - - ---- -. -- --- - -- -- - - -- - - - -- - - .

,- F 19 -,.O k'J Ama-kan.sA- I 3 . 4 r 0 0 1 9 1 Z ' Z2 dis~ance I Ziislngpur I protect cn

1 1 I 1 . . cperatsd

20 2;1C k'J Arnaiksn ah- 1 3 . 1 0017 Z1 D~stanc? blo ping 7 sirs~napl-ir li

, I - _--J_ --

i I ~rotectron - ~d .- - - - . 2; 220 k V Amarkan.sk- -[-- - 2: .42 00 08 Z2 D~s:zrce

'As ~ a . !VRIDC SCADri data

F r e q u e n c y - -. ,

1 :

0 37 Hz c t r o p 1 8 - i r c r , a a e n c . r b s ' z r v e d from th- f r c y u e r r c ~ , plot

Scht:.msiic i ' i t \~or :< Diagram: I-- 1 1 ,~ ;" \J~A~I(ANTA:.( 23,0/132 Sjc- Plctrvcrlt

Diagran-i

1

.... . . . . . .

:. , L p :: . .

. , .-., ... - . . . , i ; ........

- 7 . , ? . . - .... ... , . . . , - >-,'

:::.:.:I . .~ r I.:;,,. , -..; 5 ; ..A........ . . - -

..~ ?.

. . . / :.-:.. *-.s. .;.. - + ;

- . - , + ? - - - . . , . . . .

1 : - - j , , < ? , ? , . Z ?: -:? . , - > - . -, ~.

.. . . . . . . . . . . . , - . . . . . . . . . . . . . . . . . .... -.. .- -- --.,- . . . .

I;_ .- , 3 - : - ........... . . . . . . . . . . . . - . - . . . . . .

. ,

Detailed report on the occurrence on Omkareshwar Hydel Power Station, Madhya Pradesh: At 13:10 Hrs on 28th Aug ’12 tripping of 220 kV Khnadwa-Chegaon and Omkareshwar-Khandwa line on zone 1, Y phase earth fault which was also sensed by the hydel generators at Omkareshwar leading to their tripping. The antecedent conditions (at 13:08 Hrs) to the incident are given under:- 1. NEW Grid Frequency: 50.174 Hz. 2. WR Demand Catered: 28991 MW (Approximately.) 3. Net Inter Regional Export: 2902 MW Constituent-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 13:08 Hrs:

WR Constituents

Demand(in MW)

Generation(in MW)

Thermal & Gas


Gujarat 9637 6694 470 - 277 274


Madhya Pradesh

3617 1254 1623 - - -

Chhattisgarh 2205 2060 80 - - -

Goa 361 0 0 - - - DD 245 0 0 - - - DNH 586 0 0 - - - ISGS - 9787 945 1245 277 274


1 220 kV Om’kr-Khandwa 30

2 220 kV Om’kr-Chhegaon-Khandwa 58

3 220 kV Om’kr-Julwania 40

4 220 kV Om’kr-Barwaha 112

5 220 kV Om’kr-Nimrani 123



Capacity(MW) Actual Generation (in MW) *

1 Om’kr Unit-1 65 51 2 Om’kr Unit-2 65 53

Annexure-2.3(ii)

3 Om’kr Unit-3 65 52



6 Om’kr Unit-6 65 52 7 Om’kr Unit-7 65 Out 8 Om’kr Unit-8 65 53

*As per WRLDC SCADA data. Event Overview: The sequence of tripping and restoration at Omkareshwar is given under as per the data retrieved from MPPTCL:

Sl. No.


Time of Tripping

(hh:mm:ss)

Time of Restoration

(hh:mm)


1 220 kV Khandwa-Chegaon 13:11.45.766 13:31.33.267 N/A

2 220 kV Om’kr-Khandwa 13:11:46.115 29.08-12 09:36 Hrs

Y Phase E/F Zone 1 protection

3 Om’kr Unit-1 13:11:46.052 13:25:28.188 Gen Lockout ,Class C trip



6 Om’kr Unit-4 13:11:45.977 13.34.56.796 Gen Lockout ,Class C trip


8 Om’kr Unit-6 13:11:45.828 13:58.11.368 Gen Lockout ,Class C trip

9 Om’kr Unit-8 13:11:46.105 N/A Gen Lockout ,Class C trip

*As per WRLDC SCADA SOE Load / Generation affected: The generation loss due to tripping of Omkareshwar Hydel Units was 364 MW (*As per WRLDC SCADA and MSETCL). No load loss was reported by MPPTCL. Frequency Change : With the loss of generation ,frequency dipped by 0.179 Hz (i.e. from 50.164 Hz to 49.985 Hz). Restoration: The restoration work started with taking units in service one by one immediately after the tripping. Later on 220 kV Khandawa-Chegaon line was taken in service. Analysis : The analysis shows that the fault on the line was cleared still the unit stsrted tripping one by one.The reason for the same has to be reasoned out to take proactive action for increasing the reliability of the grid.

Graphical plot:


Fig2 . Change in Madhya Pradesh with Omkareshwar Units tripping

49.6

49.7

49.8

49.9

50

50.1

50.2

50.3

50.4

50.5

50.6

12:3

0:00

12:3

1:54

12:3

3:48

12:3

5:42

12:3

7:36

12:3

9:30

12:4

1:24

12:4

3:18

12:4

5:12

12:4

7:06

12:4

9:00

12:5

0:54

12:5

2:48

12:5

4:42

12:5

6:36

12:5

8:30

13:0

0:24

13:0

2:18

13:0

4:12

13:0

6:06

13:0

8:00

13:0

9:54

13:1

1:48

13:1

3:42

13:1

5:36

13:1

7:30

13:1

9:24

13:2

1:18

13:2

3:12

13:2

5:06

13:2

7:00

13:2

8:54

13:3

0:48

13:3

2:42

13:3

4:36

13:3

6:30

13:3

8:24

13:4

0:18

13:4

2:12

13:4

4:06

13:4

6:00

13:4

7:54

13:4

9:48

13:5

1:42

13:5

3:36

13:5

5:30

13:5

7:24

13:5

9:18

Freq

uenc

y (H

z)

Frequency

Frequency dropped from

50.146 Hz to 49.985 Hz

3400

3450

3500

3550

3600

3650

3700

3750

3800

3850

49

49.2

49.4

49.6

49.8

50

50.2

50.4

50.6

12

:30

:00

12

:33

:00

12

:36

:00

12

:39

:00

12

:42

:00

12

:45

:00

12

:48

:00

12

:51

:00

12

:54

:00

12

:57

:00

13

:00

:00

13

:03

:00

13

:06

:00

13

:09

:00

13

:12

:00

13

:15

:00

13

:18

:00

13

:21

:00

13

:24

:00

13

:27

:00

13

:30

:00

13

:33

:00

13

:36

:00

13

:39

:00

13

:42

:00

13

:45

:00

13

:48

:00

13

:51

:00

13

:54

:00

13

:57

:00

Frequency MP Demand

MP demand dropped from

3684 MW to 3466 MW

Fig3 . Change in Western Region demand with Omkareshwar Units tripping Schematic Network Diagram:

28400

28600

28800

29000

29200

29400

29600

29800

49.2

49.4

49.6

49.8

50

50.2

50.4

50.6

12:3

0:00

12:3

2:00

12:3

4:00

12:3

6:00

12:3

8:00

12:4

0:00

12:4

2:00

12:4

4:00

12:4

6:00

12:4

8:00

12:5

0:00

12:5

2:00

12:5

4:00

12:5

6:00

12:5

8:00

13:0

0:00

13:0

2:00

13:0

4:00

13:0

6:00

13:0

8:00

13:1

0:00

13:1

2:00

13:1

4:00

13:1

6:00

13:1

8:00

13:2

0:00

13:2

2:00

13:2

4:00

13:2

6:00

13:2

8:00

13:3

0:00

13:3

2:00

13:3

4:00

13:3

6:00

13:3

8:00

13:4

0:00

13:4

2:00

13:4

4:00

13:4

6:00

13:4

8:00

13:5

0:00

13:5

2:00

13:5

4:00

13:5

6:00

13:5

8:00

WR

Dem

and (MW

) Fr

eque

ncy

Frequency WR Demand

WR demand dropped from

29044 MW to 28707 MW

Detailed report on the occurrence on Satpura thermal power station, Madhya Pradesh: At 10:13 Hrs on 5th Sept’12, there was an occurrence at Satpura TPS which led to tripping of all the units at STPS generating station. While charging the ICT, due to inrush current flow, R and Y Phase of 220 kV Main Bus-I tripped on Bus bar differential protection scheme. While at the same time due to mal-operation of protection of Bus-II, all the feeders connected to it also tripped. The antecedent conditions (at 10:10 Hrs) to the incident are given under:- 1. NEW Grid Frequency: 50.121 Hz. 2. WR Demand Catered: 27024 MW (Approximately.) 3. Net Inter Regional Export: 829 MW Constituent-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 10:10 Hrs:

WR Constituents

Demand(in MW)

Generation(in MW)

Thermal & Gas


Gujarat 7999 5869 457 - 28 135


Madhya Pradesh

3373 1176 1162 - - -

Chhattisgarh 2018 1591 80 - - -

Goa 309 0 0 - - - DD 258 0 0 - - - DNH 572 0 0 - - - ISGS -- 8365 1123 1173 - -

Total 27024 23524 3275 1173 28 135


1 220 kV Satpura - Itarsi-1(Handiya) 44

2 220 kV Satpura - Itarsi-2 48

3 220 kV Satpura - Itarsi-3 47

4 220 kV Satpura - Itarsi-4 Charged from Itarsi end only

5 220 kV Satpura - Sarni 2

6 220 kV Satpura - Pandhurna 108

7 Res transformers-( III,IV) 2,2

Res transformers –(I,II) 7,4

8 400/220 kV Satpura ICT Was charged


Annexure-2.3(iii)

Generating Units’ status(prior to the incident) at 10:10 Hrs:


Capacity(MW) Actual Generation (in MW) *

1 Satpura -1 62.5 34 2 Satpura - 2 62.5 46 3 Satpura - 3 62.5 38

4 Satpura - 4 62.5 37

5 Satpura - 5 62.5 Out due to low demand

6 Satpura - 6 200 141 7 Satpura - 7 210 Out due to high furnace pressure

*As per WRLDC SCADA data. Event Overview:

• At 10:13 Hrs. due to flow of inrush current while charging 400/220 kV ICT at Satpura S/S, R and Y phase of 220 kV Main –bus-I tripped due to Bus-bar differential protection scheme. This led to tripping of Unit-1, 2, 3 and 220 kV Satpura-Pandhurna, 220 kV Satpura-Itarsi-II and Station transformer III connected on Bus-I.

• While at the same time due to mal-operation of bus bar differential protection scheme of 220 kV Main-Bus-II, all feeder connected with this also tripped.

The sequence of tripping and restoration at STPS is given under as per the data retrieved from MPPTCL:

Sl. No.


Time of Tripping

(hh:mm:ss)

Time of Restoration

(hh:mm)


1 400/220KV Satpura ICT 10:13 N/A Inrush Current

2 220KV Satpura-Handia 10:13 11:00 Breaker Tripped

3 220KV Satpura-Itarsi-III 10:13 12:35 Charged from Itarsi End

4 220KV Satpura-Pandhurna 10:13 12:50 No Indication

5 220KV Satpura-Itarsi II 10:13 12:10 Breaker Tripped

6 220KV Satpura-Itarsi IV 10:13 12:35 Breaker Tripped

7 Satpura U-1 10:13 N/A Gen-Lockout Operated

8 Satpura U-2 10:13 13:21 Gen-Lockout Operated



11 Satpura U-6 10:13 22:05 Hand Tripped

12 220 kV S/S Feeder 10:13 11:05 PAR,PE

13 Res. X-mer I 10:13 11:07 Breaker Tripped

14 Res. X-mer II 10:13 11:07 Breaker Tripped

15 Res. X-mer III 10:13 11:25 Breaker Tripped

16 Res. X-mer IV 10:13 11:05 Breaker Tripped

*As per MPPTCL

Load / Generation affected: The generation loss due to tripping of STPS Units was 296 MW (*As per WRLDC SCADA). No load loss was reported by MPPTCL. Frequency Change : With the loss of generation ,frequency dipped by 0.121 Hz( i.e. from 50.058 Hz to 49.937 Hz). Restoration: Around 11:00 hrs. 220 kV Main Bus II was charged by taking 220 kV Satpura-Handiya line. After that station transformer-IV, 220 kV Satpura-Itarsi II and 220 kV Satpura-Pandhurna were taken in service. At 13:21 Unit 2 was synchronized with the grid and later on Unit-3, 4 and 6 were taken for full restoration. Analysis : The high inrush current flow while charging of 400/220 kV ICT led to the tripping of feeders on Bus bar differential protection scheme.Also the mal-operation of bus bar differential protection scheme of 220 kV Main Bus-II was not desirable.MPPTCL have called ABB engineers for the through testing and calibration of the protection scheme Graphical plot:


49.6

49.7

49.8

49.9

50

50.1

50.2

50.3

50.4

09

:30

:00

09

:31

:58

09

:33

:56

09

:35

:54

09

:37

:52

09

:39

:50

09

:41

:48

09

:43

:46

09

:45

:44

09

:47

:42

09

:49

:40

09

:51

:38

09

:53

:36

09

:55

:34

09

:57

:32

09

:59

:30

10

:01

:28

10

:03

:26

10

:05

:24

10

:07

:22

10

:09

:20

10

:11

:18

10

:13

:16

10

:15

:14

10

:17

:12

10

:19

:10

10

:21

:08

10

:23

:06

10

:25

:04

10

:27

:02

10

:29

:00

10

:30

:58

10

:32

:56

10

:34

:54

10

:36

:52

10

:38

:50

10

:40

:48

10

:42

:46

10

:44

:44

10

:46

:42

10

:48

:40

10

:50

:38

10

:52

:36

10

:54

:34

10

:56

:32

10

:58

:30

Fre

qu

en

cy

Frequency

Frequency Dropped with Unit

tripping at Satpura thermal

power station

Fig2 . Change in Madhya Pradesh with STPS Units tripping

Fig3 . Change in Western Region demand with STPS Units tripping

3100

3150

3200

3250

3300

3350

3400

3450

49.6

49.8

50

50.2

50.4

50.6

50.8

51

09:3

0:00

09:3

3:00

09:3

6:00

09:3

9:00

09:4

2:00

09:4

5:00

09:4

8:00

09:5

1:00

09:5

4:00

09:5

7:00

10:0

0:00

10:0

3:00

10:0

6:00

10:0

9:00

10:1

2:00

10:1

5:00

10:1

8:00

10:2

1:00

10:2

4:00

10:2

7:00

10:3

0:00

10:3

3:00

10:3

6:00

10:3

9:00

10:4

2:00

10:4

5:00

10:4

8:00

10:5

1:00

10:5

4:00

10:5

7:00

MP D

eman

d (MW

)Fr

equ

ency

Frequency Madhya Pradesh Demand

Madhya Pradesh emand dropped

from 3393 Mw to 3216 MW

25000

25500

26000

26500

27000

27500

28000

49.6

49.8

50

50.2

50.4

50.6

50.8

51

09:

30:

00

09:

32:

00

09:

34:

00

09:

36:

00

09:

38:

00

09:

40:

00

09:

42:

00

09:

44:

00

09:

46:

00

09:

48:

00

09:

50:

00

09:

52:

00

09:

54:

00

09:

56:

00

09:

58:

00

10:

00:

00

10:

02:

00

10:

04:

00

10:

06:

00

10:

08:

00

10:

10:

00

10:

12:

00

10:

14:

00

10:

16:

00

10:

18:

00

10:

20:

00

10:

22:

00

10:

24:

00

10:

26:

00

10:

28:

00

10:

30:

00

10:

32:

00

10:

34:

00

10:

36:

00

10:

38:

00

10:

40:

00

10:

42:

00

10:

44:

00

10:

46:

00

10:

48:

00

10:

50:

00

10:

52:

00

10:

54:

00

10:

56:

00

10:

58:

00

WR

DEM

AN

DFreq

ue

ncy

Frequency WR Demand

WR Demand dropped from

27001 MW to 26760 MW


Remarks:

1. The Net generation capacity of Satpura STPS (Connected to 220 kV Bus) is 722.5 MW. The protection scheme employed there is of non-numerical type. This is of grave concern from the system security and reliability point of view. The immediate need is to employ the upgraded protection scheme based on numerical type relay.

2. Also immediately the DR/EL should also be installed at the generating station.

Yours faithfully,

(Abhimanyu Gartia)


FORMAT

MADHYA PRADESH POWER GENERATING COMPANY LIMITED

mlent tripping report of 3x105 MW Tons PH-I

1 0 1 T i m e & Dt. Of E.vent 1 0711 0120 12 at 2 1 :40 Hrs -1 k + a n

I 1 220 KV Rewa I Feeder i

at 100 MW load (Along with three 220 KV Feeders & 20 MVA Transformer)

line isolator to I breaker conductor found snapped

i w + h t e c e d e n t conditions of load and ' All three units running at 100 MW load --i 1 1 generation including frequency , I 1 I ) voltage and flovi in the affected I 1

i I

1 event I I

area at the time of tripping kc- 'Weather condition prior to the I

W T ~ a m a ~ e to equipment if any I

/ No 1 Clear weather --

' w t S u p p l y intermp Led 220 KV Rewa I, Stana , Kotar Feeder and all 1 the three units tripped

.4mount of generation lost (MW 220 KV Rewa I, Stana, Kotar Feeder and all ;md MWH). Po:ssibility of the three units tripped

Estimate of time to return in Satna after 00:45 Hrs, Kotar after 0050 Hrs, Charged. Unit#3 after 02:OO Hrs, Unit#l after 02: 10 Hrs synchronized on 0711 0120 12.

-

I 1 I are installed in unit control panels . So all

copies of record of all recording instruments including DR, ER,

Sequence of tripping with time

I I I units and feeders tripped almost

200 KV Feeders. (System Data of feeders enclosed ). No Such recording instruments are

Time stamping is not provided in Numerical DPR relays. And Electro mechanical Relays

DAS I available in Unit control panels .

1 speed and Governor fail . F' 1 Remedial Measure 1 Snapped Conductor replaced and Two other

Details of Relay Flags

conductors replaced and all nut bolts , clamps ( tightened Recommendations For future 1 220 KV switchyard equipment thermo vision

instantaneously Distance protection relay Operated in all 22.3- KV Feeders . Units Tripped in 11 5 % Over

I 1 improvement1 Repeat incident ( & Maintenance program is under taken as per I I

k---d I A n x r n t h ~ r ; n f r k r m ~ t ; n n

shutdown availablelfeasible. ----

N i l

Annexure-2.3(iv)

irmour TONS , MPPGCL, S' Superintending Engineer (O&M) Ge

Data Taken From Nunrerical Distance Protection Relays of 220 KV Feeders

p-1 particulars 220 KV 220 KV Rewa I Satna Feeder feeder:^

( Feeder

Active Group I 1 !

Tripped Phase k t - ABC ABC ABC Start Elements Distance Distance

( Distance Trip 1 z4

0 5 0 v e r ; n t start

Fault Alarm NO NO

/ System Frequency

I> 1

/ Fault Duration

p- / Fault Lociiti~n I 9 Mt;. I 1 XY-61.06 / XY- !.762?11tr. I

I> 1

Mtr. I I

I> 1 I

1 Van ) 122.7 KV 1 139.1 KV / 122.'7 KV

/ l 7 1 Vbn 1136.5KV 1111.5KV 1136.5KV 1

I I I

Zone 4 Zone 4 1 Zone 4 ___1

I

4.053 ohm XY - 13-13 F~hrnl ohm

COMMENTS OF SLDC

Prefault Condim:

On dated 07.10.2012 at 21.35 Hrs, MP System was rur~ning at frequency 50.15 Hz

with NEW grid. IV Tons HPS three machines were runr~ing on full load.

Qccurrencel Restoration:

At around 21.40 Hrs, it was observed that all running machines got tripped and all

cutgoiny 220 K'V lines also tripped. Further i t was informed by Tons HPS that B-Phase

jumper between breaker and line isolator of 220 KV Tons-Rewa Ckt. No.1 snapped at Tons

end.

I n the report furnished by MPPGCL, fault on 220 KV Tons-Rewa r line has taken

375.8 ms to cle'3r the fault on Zone-4 and 220 KV Tons-Satna & 220 KV Tons-Kotar also

tripped on Zone-4 at Tons end.

220 KV Tons-Satna & Tons-Kotar lines did not trip from reniote end to clear the

fi~ult. Hence all three lines tripped from Tons end and supply failed on 220 KV bus.

Thereafter all three rur~ning machines tripped on over-speed.

Line proi:ections settings at Tons, Satna, Rewa & Kotar needs to be checked to

avoid such type of unwanted trippings.

Generation Lois:

There was a generation loss of about 16.00 LU due to this tripping.

Annexure-2.3(v)

COMMENTS OF SLDC

Prefault Condim: -

On dated 17.10.2012, PIP System was running normal with NEW grid at frequency

49.94 Hz.

At 220 KV Burwaha S/s, a shut down was given on 3x40 MVA for maintenance work

and 160 MVA X-mer was on load. Loading on all 220 KV lines emanating from Burwaha

sub-station was normal.

Occurrence:

At around 12.54 Hrs, it was reported that B-phase tension string toward!; 160 MVA

X-mer has failecl and this has created bus fault on 220 KV Main bus.

All 220 t<V lines emanating from Burwana 220 KV sub-station tripped from remote

end on Zone-I1 and total supply failed on 220 KV Bus. Load from 132 KV bus was managed

and there was r1o any interruption in the adjoining sub-station.

Conclusion

Tripping took place .at Burwaha sub-station was found to be correct.

Load Loss

There was no load loss due to this tripping.

OFFI[CE OF THE ASSISTANT ENGINEER , 220 KV SIS M.P.P.T.C.L., BARWAHA

1 Location 1220 KV S/S MPPTCL Barwaha I

Time & Date of Event

Plant and/or equipement directly involved

1254 Hrs. on Dt. 17.10.12

220 KV main bus Disc insulator tention string

Description and cause of event

Failure of 220 KV main bus "B" phase tension string towards 160 MVA X-Mer side. Due to this triping of all 220 KV feeders from other end & only 220 KV Handia feeder triped from Barwaha end also.

Antecedent conditions of load and generation,including frequency, voltage and flow in the affected aree. at the time of tripping including weather condition prior to the event.

All relevant sysqtem data including copies of record of all recrding instruments including DR ER,

Loading of Feeedrs at the time of tripping (12:OO Hrs.) Voltage :- 23 1KV/ 49.9 Hz (01) 220 KV Barwaha-Handiya:- 105 MW, 280 Amp., 12 MVAR (02) 220 KV Barwaha -1tarsi:- 80 MW, 230 Amp.,O5 MVAR (03) 220 KV Barwaha -1ndore-1:- 06 MW, 50 Amp.,20 MVAR (04) 220 KV Barwaha -Indore-11:- 06 MW, 50 Amp.,20 MVAR (05) 220 KV Nimrani Tap-0mkareshwar:- 68 MW, 220 Amp.,-53 MVAR (06) 220 KV Barwaha-0mkareshwar:- 12 MW,105 Amp.,39 MVAR (07) 3x40 MVA X-mer:- OFF(Under Shut-Down) (08) 160 MVA X-mer :- 110 MW, 285 Amp., 28 W A R

Duration of interruption and demanii and/or generation (in MW and MWH) inte~rupted.

Interruption of 220 KV main bus only from 12.54 Hrs.to 18.15 HIS. No interruption to any area due to this tripping.

DAS etc.

Sequence of tripping with time i 1254 Hrs. All 220 KV Feeders Tripped on other S/S and 220 kv Handia feeder also tripp !?om Barwaha end , 132 kv sanawad feeder tripped from sanawad end,

1 132 kv Chhoti khargone feeder tripped from chhoti khargone end only,

letails of relily flags

Lemedial measure

101) 220 KV Itarsi- :- CN Phase Zone-II, 178.0 Km.at Itarsi end , At barwaha end no indication no tripping

:02) 220 KV Handiya:- CN Phase Zone-I1,O.O Km.at Handia end, At Barwaha s/s end inclication Earth Fault tripping

:03) 220 KV Indore-1:- C Phase Tripped Zone-11, 58.6 Km at Indore end At barwaha s/s end no indication no tripping

[04) 220 KV Indore-11:- B phase, Zone-I1 !i6.82 Km.at Indore 11 end At barwaha end no indication no tripping

(05) 220 KV 0mkareshwar:- B phase , Zone-I1 31.7 Km.at Omkareshwar end

At barwaha s/s end no indication no tripping (06) 220 KV Nimrani Tap 0mkareshwar:-

(A) At Barwaha S/S:- At barwaha e n j no indication no tripping (R) At Nimrani S/S:- F! Phase, Zone-11, 70 KM (C) At 0mkareshwar:-B Phase, Zone-lI,31.7 KM

(07) 132 KV Chhoti khargone S/S:- Earth Fault, CN Phase, Zone-111 At Chhotikhargone end, At barwahii s/s end no indication no tripping

(08) 132 KV Sanawad S/S:- Earth Faut, C Phase, Zone -I at Sanawad end At barwaha s/s end no indication no tripping

Replacement of failure disc insulater done

ASSISTANT ENGINEER 220 K V S B M.P.P.T.C. L., BARWAHA

A single lint: diagram indicating tripping and affected area is also enclosed herewith.

Load loss : --

There was a load loss of about 160 MW for 10 to 15 minutes.

Conclusion :

The situation would have been prevented if WRLDC operating staff had acted in conipliance with IEGC, UI regulations and operating procedures which clearly state that Type A,B & C messages need to be given if there is overdrawal below frequency 49.8 Hz. WRLDC has sto~tped giving Type A, B & C message and a simple message without indicating frequen':~ and nature of threat &the Grid. The actions of WRLDC are totally in violation of IEGC I UI Regulations and the decision taken in special OCC meeting of WRIPC. If such aci:ions continue the same may lead to serious threat to MP systeri.

Encl. 1. A copy of :system over-view on 27.10.1:Z at 21:27 Hrs.

2. A copy of system over-view on 27.10.1:2 at 21:50 Hrs.

3. Fax-messa~ge given by WRLDC

4. A single line diagram

Annexure-2.3(vi)

COMMENTS OF SLDC

PI-efault Condition: -

On dated 08.11.2012 at around 13.50 Hrs, MP System was running at frequency 49.8 Hz with IVELV grid. Other parameters related with PIP are given below-

Thermal Generation 2194 MW Hydel Generation 951 MW Central S12ctor schedule 3071 MW Central S12ctor drawal 3295 MW M.P. Derrand 6420 MW

Occurrence:

As around 13.53 Hrs, it has been reported that at SGTPS, bus-bar protection operated at 400 KV bus-11. This has resulted into tripping of 500 MW unit No.5 a r ~ d 400 KV Zrsingripur-Damoh 1 & Ii, 400 KV Girsinghpur-Baico feeder.

Relay indications appeared in the various transmission elements and restoration are given as under:-

SN Name o f Trippin 1 1 feeder b l a t e ' ( Time

operated

e on Bu! (Hrs) 1 Trippi

I ng

i) 37G1/32R Class-B Trip ~ I

iii)96X1, Bus-bar protn. I

(Main-11) Optd. GRP2:-

I I I

I i)Class-B trip I

I I ii)186B1186BX I

1 GRP3:- I

i)37G/32R Class-B trip I ~

!- ! I I 1 I - 1 I

I 2 . Brs.- 1 08.11.121 13.53 2 . 4 4 4 SOOKV 996, BYS-bar xo tn . (?.laiii- I Damoh-I I G8' i"1~ 1 Bus-I1 11) Optd. I 1 B a y - 4 0 g I I

t_ I

1 2 , Brs.- ; 08.11.12' 13.53 0 8 . 1 1 . 1 ~ 21.47 -382 400Kq 1096, Bus-bar protn,

Generation Lo=

There was a generation loss of around 30 LU.

Conclusion

It has been reported by SGTPS officials that bus-bar protection on bus-I1 ma1 operated and kept off for testing and checking of protection.

annexure-2.3(vii)

OFFICE OF THE SUPERINTENDING ENGINEER (ET&I) - I11 SGTPS. MPPGCL. 6IRSINGHP.JR DISTT. - UMARIA ( M P. i Fax No, 07655-262232 Ph. No. 07655-260214

-, !...' Ernail: - s ~ ~ ~ ~ . ~ ~ ~ @ ~ ~ - a i l , c o [ r ! .

\Letter No / ti1 1-1 8ODISGTPSIT&C-Ill/ / 366 BRS. Dtd. 4'1- 12- 12

TPi! S E iSLnC) bJ P P T.C I - . J a b a l p ~ r E-marl sldcrnpseb@ yahoo. corn

S u b . Tripping analysis repot of 400KV switchyard on dtd 08,. 11.12 $24.1 1 2

Please f i ~ , d enclose here with t he trippicg report of 400Kb feeders and urits a s desired

d

I Tripping/lZestc?~aing Report of [)ate-08/11 /12 - . _ *_. . . . . . . . . . . . . . _ __-_ _ ---.- .r - T

- - - . , . - . . ~

Tr! J ~ I I I ~ l<esrminy S. h n m t c:' --T,;;-- - r i n w 1 Dare ] 'I 'imr liefi) Clonuected I Rcliiy (>l:~r.ttt'.i V F1:cilc.l- , 1 ( ~ y s . ! i 1.e 011 HLij i il-1i.s.1 I

10. , ! i T'ril- 1

I I I ping i I !

-------. ~

i \ f \AJ + . -- -~ GRP:-1

I I 4,OC)KV 1 :~.(IoM:A; ; i)37(ii ?ZR ( ' . ; i s - B I rip 1 i Qcllcia~or 1 ,]$!l I 2 I 3:53 I 1 10:36 485 B!~s-l l , . . . i i j l 36,k.l S 6 A L

I I I 1 :\;I?-! I I 1 11: I 96x1. 3~1s - i :~ r ;I! i.tr ( l l a ~ n - I I 1

! 1

I I O ~ T ~ I .

I I I GRP.-2

I :)('li::.s-i? L I - , ~ I I I

1 I i 1i)lSbB.1 R6RS

i I

CiRP.-3

i ! i ) 5iCli:!2!< (.:l.1,<-[3 t i j j ~ ? , I ,,-- I ! .--_ . -.

f - - i - - _!_-_ . . _.

i .- _- -. - - - - ._ "~

I H f i - 2 . f ~ ~ j I)-,\ , j ; - ! ' O f : Y l \ ~ l 2 i 1 1 4OCKV

' 1 [jkl,!.-L; c(,! 1 5 3 OR!] i 1 11 :47 464 / tins-ll [)~C>.BUS-I>,~I. ,7t 'i!!:7,( y(!i;i t7- [ I ) Optd

' 1 ; L-. .r- . -i-- - - ._ t 1

--- A - -

3. ' ,Bias.- H ~ ! c ~ I i -t(!OKV / 1096. 5 ~ ) s - b a r pro:\-I, i \qalnll l) B ; I ~ - J : O 1 2 1 5 1 2 i : 3 7 ' -382 ; Bcr-I1

i . . . . . . . . . . . . .. . -, . .- . . . . . I .......... i I

,- -, 1 J-- I . -

C

.::,s ( I & ( . ' ) - I l l

OP 'OO

@A. .isL'. '@$ .

90. -ct 2. .fl, '8

2. "., cs

00. ($

@, . ., ;9s

L'

Qp. .$, L

a 'q' 2, ."@, 1.

0 ;"s p. .c, '+ "

8,. .,, '+ ' 90. .,,

'c' A-

+.st@]/ 'L"

"a. +$> 'O$ '-

00. *?[ '0 qi,

MADHYLi PRADESH POWER TRANSMISSION COMPANY LIMITED '@ -Q STATE LOAD DESPATCH CENTRE a-m -

NAYAGAON, JABALPUR a* p~ a 9001 2108 Telephone (0761) 2702740/2660240 Fax (0761) 2664343 e-mall sldcnipseb@vahoo corn s3 a001 2008

No.07-05/RPC-511 9 , ~ CT '1 Jabalpur, dtd: 15- , \ 2 ,L

$''/13 - .. The Deputy General Manager (GM), Power System Cperation Corporation Ltd., 7 17/ /k / /~ , Western Regional Load Despatch Centre, F-3, MIDC Area, Marol, Andheri (East), Mumbai - 4000113. Fax: 022-28202630

Sub: Tripping report of the occurrence on 10.11.2012 at SGTPS, Birsinghpur.

. . . Dear Sir,

Please find enclosed herewith the tripping report furnished by MPPGCL in the

prescribed format alongwith DR prints of the occurrence on 10.11.2012 at Sanjay Gandhi '

Thermal Power Station, Birsinghpur with comments of SLDC.

Yours faithfully,

Encl: as above,

SLDC, IY PPTCL, Ja balpur.

Copy to :- .,,- 1. The Member Secretz~ry, WRPC, F-3, MIDC Area, IYarol, Andheri (East), Mumbai : 400093. 2. The Executive Direct or (O&M:Gen.), MPPGCL, Jabalpur.

COMMENTS OF SLDC Prefault C o n d i m : -

On dated 10.11.2012 at around 05.25 Hrs, MP System was running at frequency 49.96 Hz with NEW grid. Other system parameters related with PIP are given below-

Thermal Generation 1784 MW Hydel Generation 874 MW Central Sector schedule 4267 IYW Central Sector drawal 4594 IYW M.P. Dernand 7245 MW

Occurrence: At around 05.30 Hrs, i t was reported by SGTPS, Birsinghpur that flashover observed

i l l B-phase Bus-[I isolator of 400 KV Birsinghpur-Damoh I PGCIL feeder.

Subsequently all 400 KV feeders along with 500 MVA ICT (400/220KV) & 210 MW running units N3.2, 3, 4 & 500 MV unit No.5 also tripped. Faulty section was isolated and zystem was normalized in due course of time.

Relay intjications appeared in the various transmission elements and restoration are <liven as under: -

:1. 500 MW 10.11.12 05.31 i Generator 1 I

-Load Date Time befor

7

cted

I) 37G1/32R Class-B Trip

1i1)186A, 186PX GPR2:-

I i)Class-B trip li)186B1186BX GPR1:- I

i)32G2/32R Class-B t r ~ p ~i;Over vdtaqe 1i1)21/50 DGM T r ~ p I i)286A, 286AX

I

GPR4:- I

1 1)286B, 286 l3X

( H r s )

- - . - - - -- +

displacement relay)

I 400KV ,

e Trippi n g MW

1 ~ y - 4 0 a I I

3 ~ r s 7 ~ a t n 1 10.11.12 05.31 - - - - 10.11: l~ 18.06 --

L- 2 3 2 - 4 0 0 DPR 2 m r d m a n d 8 6 -- - -- - - -.

annexure-2.3(viiia)

1 Bay-406

Damoh-I1

10.11.12

Brs.- Bay-

(210 MW), I

GT Stand by Earth Fault I

~

? ~ N ~ 1 0 . 1 1 . 1 2 i (210 MW) ~ ~ I

Conclusion i) I t w;~s gathered that 400'KV bus-bar protection was kept out by site officials. 1f

bushar protection had been in service this tripping could be minimized.

05.32

05.31

05-31

05.31

ii) 500 MVA ICT (4001220 KV) could not trip timely during this occurrence, IF TRIF'PED other tripping of unit IVo.2, 3, & 4 would have been avoided.

05.31 ' 1 0 1 1 1 2 !

iii) The p romt ion settings of all the equipments / transmission elenlent needs checking.

11.11.12

10.11.12

1 0 , l l . l

10.11.1

Generation LC- There was a generation loss of around 141.50 LU.

07.53

Frequency Chanqe The frequency dipped to about 0.12 Hz on disturbance. A graph indicating change

08.01

06.43

06.43

8.14

of frequency is enclosed.

154

404

406

-476

133

/ BUS- 1

I 1 220

1 BUS- ,

KV

GT Stand by Earth

(over voltage, DEF Trip, Z

KV 1

Bus-I 4 Reverse -- Zone) 400 Hand tripped.

1 KV BUS- I 1 400 DPR 21.1 ancl 21.2 and 8

(Over voltagt?, D.E.F.Trip

Bus- 2-4 Reverse iione) I

I 1 i 220 i GT Stand by Earth Fault I

KV 1 I

CPliF1Cb; OF 'THE SUl'El<TNTICNt)INC; ICNG1NEER (Lrr&I)-111 SG-IPS MPPGC'L, 13lRSINGkIl'~ jl<, DlS'r'17. - L!A4*4 RIA (b!.l'.) - 1

FAX No. 07655-362232 Lxmail: seeti3(L$gmail.com

'I>L). l'he S.Ji.(SLDC') kl .I> . \'.'S.C. L.. Jabalpur (M.1')

Sub: I ric)pi!lg analysis report of 400KV Switchyard on Dated 10. I I . 12

With rcI'crcncc to above, detailcd tripping report \.viLh DK!li\:cnL loggcr pri~ltoil~s is subrlii~ted hcsevith Sor f'urthcr analysis anti guidelines.

:\s PC- thc 11.i.uJs ;.\\~ail:ihlc. all t111: connc.clccl fccdcrs in 40Ot;i' S13.1 PS. fSirsing11pur inc!udii~g 1CI' were rrippcd and S:iult clcarccl within 1 second alicr tllc tiashover iniiiaiion in [%-phase 1311s-I l Isolatol. of 400KV 13RS- Damoh-1 (llai\. No.410). Protection opet.ateci IIII difkrcrlt fccders are mcntioriccl below:-

. - -- DPR 21.1 and 11.2 and Y O (Overvol~agt.. r1.F.F Trip)

No. I ~ - ---- - . , .. . . . ! 1 scttir~gs -t7--, - 7 ! 0 1 i iOOi<? . I3RS-Da~noh-l ( 05:; l 1 lrs , ' DPR 2 1.1 :u~il ? i 2 ~ ) O \ c r \.olti~pe-

I i 1 (13q :\.0.40~1) i ' and 86

I I 1 10'!.0 \f , i th iscc ! ! I i (0vcrvclltrtgc. time .Ic!cty

i , L 1 I i . i . '['rip. DPR ii) Ilcvcrsr. %orici%-

blain-Il trill } 4) t in~c .;ettirlg i:, i

. . .. .. .... - . -- . . . 15941 ~ L ~ r ~ d . I see. i- 02. 1 400KV BRS-lli~n~oh-11 03:3 1 1 lrsj I h n d ~rippcd I

'

1 5% ,u~cl 1 sec I -. - - - - -1 i)Ovcr '~sl tagc-

I 1 (Ha\ Xo.408) . . .- -. - - F . . ~ . -

( 0;. ' JOOKT< RRS-Ralro

1 1 o".:, w'III 5scc time clel:~y i i ) Kcvcrsc Zone 1 (%-4)limc setting 15

I i 1 .. . . .- .~ 1 .~ t- -~ - . - 1 O S : ? O I1rs 1 1)1'1< 21.1 ant1 21.2 ; i)Ovrr'~. ~ o l t a g c -

I 1 i i ( S ! i ~ j h!0.4! 0 ) ) arid 80 I I 0%; n it11 ise: I

1 i ( o \ ~ e r v o l ~ ~ i g ~ > I 1

' t i ~ r ~ c ilcl:~!,

1 L),L,.b'. ' 1 rir.7,-4 i

! i i ) ficvc1-bi. /o~-c' 1 I / lic\lcrsc ~ o ~ i e ) ! (%-4) time scttirlg is I I

........................... , . . . - . . . . . . - i . -

07. : i i n i t i<c.1.2 (?l[~h..l~i.') 0 5 : 3 1 I Irs , ( ; I ' s(ancl hy l m t h

f - .+. r- ........ 1 ti1~1Il

......... ............................................

1 friull

I 08. ; I Y 3 2 1 O 5 : 3 1 Hrs ' 1 s i n t : I I

1 -..----p.---7-.--..-.--. --- -. .

Irs ?-'C;'l- stand by t:arth ! 1 fault . . . . . . . . . . . - L .- -

.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...- ~- .--.- .... - -~

51-!1W~~~;ener .dor 0 5 : j l H r s i i31JKI:- ; i j 00% xtalor liar111 I 7 2 I - ; iBdt :- 1 OC', 3sec j

I j 13 trip I seco11il;iry. i iij0O1:/o slator l<atl11 1 1 ) ()vervoItage :- i I I

i I ikult a . I21\ / . 5 sec I i

Ko~c:i) I<c.vcssc %one (%-4) ~ i m c sc~ting Ibs tJ(;CIL t'ccdct.s is I i?/;~ a~icl I scc. i i ) Kc\ ,rsi: tc>rlc (%-4) tilllc scttilig fifr h;fI)P.t-c.'I, IICLI~I-'s is 1 O1?.b ancl 800111s

I i !

Itchy scirin~s of'G1' stand by t:a~-th f<t \ i l t in rcspccl oi'I'~iir. Uc1.2,3 ant1 4 Iriay plc.:ise l ~ c . ob~aincil I'ron-t their end.

! j i i ) IX613: I X O i3X secor1tlar.y.

1 ! G I ' l X l :- i i i ) I+icL u p i I

I i I / i)::7Ci?..'ilR ('lass- ( i i l~pc ' ia~~cc -: /on;-

; H trip 1 2 ccttings 2.1 oh111

I I I ii)O\~er voltage ( Lsec. I I i I i i i ) 21 ; 5 0 llCiJ,l

I i I 1 I 6 I I i

! 1 CiP1i-I:- i ! I : i)28613 , 286 13X

i

i i i ) 1 X(i:2. 180 A X I

sciolidary. b. 154V GP112:-

i) CI;ISS-ii trip insl;inia~o~.lc

t ic

....

Name: b~rs~lighpurl DAMOIi-4 7SA522 V4 6 Var

Filename:

F ~3OCUME-1\~OWNER\C;ESKTOP\BIRSIN~2iP7DI\G~ST\00G00008\SAMPLES\FAULT\FR000007

Fault start: 7 0 l i 2012 05 31 05 330

Scann~ng frequency:1!100 I i z

C u r s x 1: 352 ;ns

Cursor 2: 927 MS

Representation: sicoricary

I-S? UB TF(IF Power Sw ng

Dis T Carr rec - .

DIS T SEND Dis Pickup L1 Dls Plckup L2 DIS PICKUP L J DIS Pickup E

DIS Plckup 22 DIS Plckup 23 01s Plckup 25 Dls T r ~ p Z l i l p

131s Tr!pZI E l p - Dls Tr1pZ2i3p Dis TrrpZ31T3

DIS TRIP 3p Z5 FF P I C ~ I J ~

Relay PICKUP Relay TRIP L: Reay TRIP L% Relay TRIP L3

Relay TPlP FltRecSta

Upn-e> Pickup Uph-e>(>) TRIP

EIF Trlp 3p Line c l o s ~ r k

LIUCBR-PHO . . - - .

- - - .- - . . - .- , --- LNCBY-PHO -

- - - -- -- -- -.

LYCBB-PtIO - . - --

TCBR-PI10 - * -

TCBY-PtIO

0 0 1. 2 0 '1 0 6 L 8 1 9 1 : 1 C 1;s

CCBR-P!-,:j fLiii1n2UlSC;P

o/v-2 Op MA!TUCLOEC! 813 i'f?07- CiP

AR C' iJ AK Unsu

DTRecl12

SI( iR:\ 4.4 hiistnglip!ir? K C R G A ~ I iSk.CJ?? V4 6 '!a1

. . . . - . . .

Name: airslnghpcrrl KOREA-I 7SA522 V4.6 Var

Filename:

F \[~OCIJME-~\OVVNEF~\DESKTC)P\BIRSIN~~\P~D~\GV\ST\OOOOOOO~\SAMPLES\FAU LT \FF?00300 3

Faiilt start: :14.11.2012 11:17.11.776

Scanning frequency: l OGG Hz

Cursor 1: 285 ms

Cursor 2: ;'59 m s

Representation: r econdary

>Trig.Wave Cap Flag Lost

501-1s TRlP 0At3'3 50-STUB TRIP

ti8 Power Swing OET Pswing TRIP

21 TRI' 21 TRlP 3p 22 21 TRlP 3p. 23 21 TRlP 3p. 24 Relay PICKUP iRelay TRlP 0 1 4 Relay TRlP 0 B lielay TRlP 0C

Relay TRiP FltFiecSta

59-Vpg TRlP 50Nl51 N Tlip 3p

L~ne closurt: -NCBR-PHOP LNCBY-Pt-IOP LNCBB-PHOP TBCCBR-PHC

TBCY-PHOP TBCB-PHOP MN-20PTD ON-2OPTD

LBBOPTD I3BPROTN.OF.

AlROPTD AiRUNSUCCE

RECDIFF.OP

K t F 'JP TG C;:c,rylP OP r A12 START

'JairilCR Main2CR

UTRecl 12 KZCTAUXPPT

NGRAUXOPTD

Tripping/Rcstclring Report n f Date-I Oil 1/12 - -. . - - - , , . . - - . - . . . . - . . - - - - - - - - -. . . - - - - - - - . . - - - - - -. -- -.-r. .. - -. - . - . ~ - - - - -

I -1 1.1ppi11g 1 Rehtor ing I..na~i 1

1 S . ' ',"\nls ~ l f h ~ f . 1 1 C~):I\:~LI:?, 1 , I l imz X:li[), C!I.L~~:I::J ! h' kche: ' (H1.5.j I I s '" I

l o l I ! Tril?

I I I _ tTlj-,<.7 5 j i !

I .--- 1- . , :\.1v,.' I I -- - - - - - - - , . - - , I ! CiRP.-I : 1 . ' 5 >!)\.I \\, I I I 4[l<jK\j :) :TI.; 1 TI.!] . : r: : ~ < . y .!< i rj :

I _ I , ! I I 2 0 . 1 I !;.I :'17.4? ls(j5 I ~ ~ I s - [ ] i i j +Oi4,51;: I , , c;~YI:>, !ALI . :

I Hs!,- 1 i I

I I ; iiir ; Kh;\ i ' C.\S 1 1 I 1 (;UP:-?

I i 1 i ) C l a s : ~ . l \ :, 1 1 ) I I I i;) I SO15. I Sfl3:~: I i I , G K P : - I j I - - 1 I I i 1 >/C":! l< C ' ,ass-R r~. ,p

I i i / : . l \ \cr \ 8 ~ ~ : ~ ~ ~ ~ i I I

I ! I i:i) 21, 501 )(i'\,i [rip I I I

! L ) 130;\ :1i,(5,,\.) I

I GRP:- I 1 i 1 i '1 I~ :!s(~ I-: i

I I i i !

w - -- --L -.- L ' - - - - . . . . - - - . - . .

I I

I i - ? , I ( ' I ' I .IOC\K\' ! I 0 , ' ; 1 10/11,13' 0 i - 8 s

I . 4 - h\rcl~tl.a! \i! pi ~ u , . ~ . . c ; i -L,l.i>

1 1 Q,!\-41!2 I ,..--.. . .. . I - 1 1 1 ~- . - . . -

3 . i$ys . 33i1KV DPR 2 I , : L ~ ~ l L l 2 ! .: . i l j K O (,[I,, <I

I I : 1 : 1 2 I 1 i O i : i l ! > j l f i : O t , ' 2 2 2 Bus-[ ~ o l r a g e . 15~11 -406 1 1 1 I -~ --.- . -- -- - - - - ~ - .~ ---- -- ' . E F rl,ki_ -, ~ . p~ - - - -.

I I

i 1 4 !:I: s - I i 400K\/ , 1 - 1 1 I , 1 I I I : 1 I il 1 ' 1 2 i ( .)S:Ol 1 404 ' EJo,-l I 1 H~I-,c! [ ' r ip I,::\

1 ' j32!..4;!8 1 i I . .. . , . . . . -. 8 - , . . ._ . - - _ I - , - - - . - - _ -

1 3 , DPX 2 : . I , l , I C : i : ,ll?.l PI'> I

Detailed report on the occurrence on 10th Nov, 2012 at Birsinghpur, Madhya Pradesh: At 05:31 Hrs on 10th Nov’12, as the bus bar protection of Birsinghpur was kept out of service ,the flashover in B-Phase Bus II isolator of 400 kV Birsingpur-Damoh I line led to feeding of the fault to all the feeders connected in Bus-II. These resulted in tripping of all the feeders from Bus-II and the delay in tripping of 400/220 kV ICT led to sensing of these fault by 220 kV side generators and their tripping. The antecedent conditions (at 05:20 Hrs) to the incident are given under:- 1. NEW Grid Frequency: 49.958 Hz. 2. WR Demand Catered: 32735 MW (Approximately.) 3. Net Inter Regional Export: 1469 MW Constituent-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 05:20Hrs:

WR Constituents

Demand(in MW)

Generation(in MW)

Thermal & Gas


Gujarat 9978 8096 0 - 186 0


Madhya Pradesh

6563 1812 340 - - -

Chhattisgarh 1997 1647 0 - - -

Goa 282 0 0 - - - DD 219 0 0 - - - DNH 569 0 0 - - - ISGS/IPPs -- 12156 67 1477 - -


1 400 kV B’pur-Damoh I 419

2 400 kV B’pur-Damoh II 408

3 400 kV B’pur-Balco -462

4 400 kV B’pur-Katni I Idle Charge

5 400 kV B’pur Katni II 223

6 400 kv B’pur-Vandana Out to control H/V

7 400/220 kV ICT -102

8 500 MW Unit -5 503

9 210 MW Unit-1 Out on BTL

10 210 MW Unit-2 132

11 210 MW Unit-3 157

12 210 MW Unit-3 166


Annexure-2.3(viiib)

Event Overview:

• On 8th Nov-12 at 13:52 Hrs, bus bar operated at Birsinghpur due to unknown reason leading to tripping of units and line on Bus-II. During that time 400 kV Damoh-B’pur ckt-I was undergoing LILO work at Katni which was completed by 9th Nov’12 and the line is at present 400 kV Damoh-Katni I and Katni-B’pur I. The system was restored immediately by taking out Bus Bar protection for inspection.

• The bus bar protection of both the buses was kept out of service for inspection on 10th Nov-12.

• On 10th Nov-12 at 05:31 Hrs, flashover occurred in B-Phase isolator of B’pur-Damoh II line which fed the fault to Bus-II leading to tripping of all the elements connected with it. The fault was also sensed by the 220 kV generators leading to their tripping.

• The 400 kV B’pur –Damoh II was hand tripped by station operator by mistake instead of faulty line 400 kV B’pur-Damoh I.

The sequence of tripping and restoration at Korba (E) is given under as per the data retrieved from WRLDC SCADA and MPPTCL.

Sl No.

Name of the transmission element/

Unit


Relay indication Time of restoration

(hh:mm)

1 400 kV B’pur-Damoh II 05:30 Hand Tripped 08.01

11-11-12 2 400 kV B’pur-Damoh I 05:31 DPR,O/V,DEF operated 06.43

3 400 kV B’pur-Balco 05:31 DPR,O/V,DEF,Z-4(reverse zone)

operated 06.43

4 400 kV B’pur Katni II 05:31 DPR,O/V,DEF Operated 18.06 5 400/220 kV ICT 05:31 Neutral Displacement relay 06.50

6 500 MW Unit -5 05:31 Class B trip, O/V 07.42

11-11-12 7 210 MW Unit-2 05:31 GT Standby earth fault operated 08.14 8 210 MW Unit-3 05:31 GT Standby earth fault operated 07.53

9 210 MW Unit-3 05:31 GT Standby earth fault operated 07.57

*As per WRLDC SCADA and MPPTCL Load / Generation affected: The generation loss due to tripping of Units was 958 MW (*As per WRLDC SCADA). Frequency Change : With the loss of generation ,frequency dipped by 0.34 Hz( i.e. from 50.128 Hz to 49.788 Hz).The energy loss was 141.50 LU(As per MPPTCL-SLDC) Restoration: Faulty system was isolated and restoration work started with taking the 400 kV Balco-Birsinghpur and Birsinghpur-Damoh-I lines into service. After that 400/220 kV ICT was charged and taken back into service. Then 210 Units were taken into service one by one to restore the system. Analysis : On analysing the event, it was found that the protection scheme being used at 400kV Birsinghpur is of non-numerical in nature. The delayed tripping of 400/220 kV ICT which led to feeding of fault to 220 kV side eventually resulted in tripping of units is also an issue which need to be investigated. Also operating the system without any bus-bar protection was very undesirable and made the whole system vulnerable .Such practices may be avoided.

Graphical plot:



49.4

49.5

49.6

49.7

49.8

49.9

50

50.1

50.2

50.3

50.4

2:59:00

3:06:22

3:13:44

3:21:06

3:28:28

3:35:50

3:43:12

3:50:34

3:57:56

4:05:18

4:12:40

4:20:02

4:27:24

4:34:46

4:42:08

4:49:30

4:56:52

5:04:14

5:11:36

5:18:58

5:26:20

5:33:42

5:41:04

5:48:26

5:55:48

6:03:10

6:10:32

6:17:54

6:25:16

6:32:38

6:40:00

6:47:22

6:54:44

7:02:06

7:09:28

7:16:50

7:24:12

7:31:34

7:38:56

7:46:18

7:53:40

Frequency(Hz)

Frequency

Frequency dipped by 0.34 Hz due

to loss of generation

Remarks: The outage of bus-bar protection without informing the SLDC is not desired as it will affect the reliability and pose as a threat to grid security. Such communication gap and indiscipline has led to tripping of units and lines and should be taken as a hard lesson. The protection system at all thermal power station should be upgraded to numerical scheme. The same recommendation has been given in the previous report when the disturbance took place at Satpura TPS on 5th September, 12. At present there is a need to review the protection system at the sub-station so that further occurrence could be avoided.

Yours faithfully,

(Abhimanyu Gartia)


Maharashtra State Electricity Transmission Co. Ltd.Testing & Communication Circle, Aurangabad

Dr. Babasaheb Ambedkar Road,Old Power House Compound, Jublee Park, Aurangabad.

MAHA KANbvU Phone:0240-2363317 E-mail: [email protected] harashtraStateEWicftyTransmssionCo.LW, Fax: 0240-2355370 [email protected]

RIGHT TO

INFORMATION

No. SE/TCC/ABD/TS//)-5/ 3 3 Date: 7-/2

To,

The Chief Engineer,MSETCL, Trans O&M,Corporate Office, Mumbai.

Sub: Operation of 400kV Main Bus-2 at 400 KV S/S Girwali on Dt: 09-07-12

On date 09 July 2012 at 16:02 hrs, 400kV Bus bar protection of Main Bus-2 at 400 KV Girwalisubstation operated, details are as under:

Details of Protection: Bus bar scheme maks ER CSC-150

Date of Commissioning: 09 May 2012

Bus Connection status of all Lines / Equipments prior to Fault:

Sr. No Feeder/ Equipment Position

1.

400 KV PRL-CHD-I MAIN -1 BUS

2.

400 KV PRL-CHD-ll MAIN-II BUS

3.

400 KV PRL-CHD-III MAIN-I BUS

4.

400 KV PRL-LKD-I MAIN-I BUS

5.

400 KV PRL-LKD-II MAIN -II BUS

6.

400 KV PRL-SLPR MAIN-I BUS

7.

400/220KV ICT-I MAIN -I BUS

8.

400/220KV ICT-II MAIN-II BUS

9.

400/220KV ICT-II1 MAIN-II BUS

10. 400 KV PGCIL-I MAIN -1 BUS

11. 400 KV PGCIL-II MAIN-II BUS

12. 400/220KV SPARE ICT MAIN-II BUS

13. 400 KV TBC MAIN -I BUS (FOR SPARE REACTOR)

The sequence of tripping of equipment & lines affected during occurrence are as below:

Sr.

No.

Time Sequence of Tripping LBT MW Remark

1.

l6:02Hrs 400 KV PRL-CHD-ll 330 MW

2.

16:02Hrs 400 KV PRL-LKD-II 537 MW

3.

16:02Hrs 400/220KV ICT-U 28 MW

4.

I6:02Hrs 400/220KV ict-:;ii 36 MW

5.

l6:02Hrs 400 KV PGCIL-II 159 MW

6.

l6:02Hrs 400 KV BUSCOLPLER 80 Amp7

.16:02Hrs 400/220KV SPARE ICT

8.

16:02Hrs 400 KV PGCIL-I 158 MW Tripped at PGCIL end only.

Annexure-2.4(i)

MAHATRANSCOMhmMa Stale EiecthcHv Transmsion Co, LW



Phone: 0240-2363317 E-mail: setccabd 1 (ajgmail.com.Fax: 0240-2355370 se2500(a).mahatransco.in

RIGHT TO

,NFORMAT,ON

No. SE/TCC/ABD/TS/ -S/ Date:

Relay & Window indications at 400 kV Ginvali End:

Bus Bar Protection:

Sr. No. W.I R.I Remarks

1 l)Z-2Trip. Diff. Optd.BZ-2, A phase

96 operated for all baysconnected to Main Bus-II

Lines / Equipment Protection:

Sr.

No.

Name of Line /

Equipment

W. I. R. I. Remark

1.

400 KV PRL-CHD-II 1) A/R lockout, CBlock out, M-2

protection operated,Low air pressure

86A, 86B, 86C- 3 flagoptdI86A, I86B. Main-I A/R

lock out

2.

400 KV PRL-LKD-II l)M-2 Carrier fail,direct carrier fail

96X,

3.

400/220KV ICT-II 1) Cooler control Acfails. (220kV side)

Bus bar trip relay 96, StartAC, I>4, IA=923amp,IB=100.9amp,IC=960.3amp, 86A &86B

4.

400/220KV ICT-III Master trip Group AOptd.(400kVside CP)Master trip relayoptd.(220kVside CP)

Main trip relay 86A-2 FlagMain trip relay 86B-2 Flag

5.

400 KV PGC1L-II Parli line-2 Main-1/2

operated, yar\\ line-2main-1/2 carrier

received,

A/R unsuccessful

Main-1:21.IXR.21.1XY.

21.1XB- 1 flag each, 86A,21.1, Rph trip, Yphtrip,Bph trip, Z-l trip, Z-1Btrip, CMR 30K- 1 flag,86AX - 1 flae.Main-2:

21.2 XB-1 flag,86B-2flag, 30F2, 21.2, Bph trip,Z-l trip, Zcom trip, 130K-1 flag, 86 BX-lflag. Directtrip send 30S1/30S2

6.

400 KV

BUSCOUPLER

l)Zone II Trip 196 (on Bus Bar Protectionpanel)

MAHATRANSCOf.<ah3f3 tf3 Stale Electnoty Tfan$mssien Co, LW


Dr. Babasaheb Ambedkar Road,Old Power House Compound, Jublee Park, Aurangabad.Phone: 0240-2363317 E-mail: setccabdKajgmail.com.

Fax: 0240-2355370 [email protected]

RIGHT TO

,NFORMAT,ON

No. SE/TCC/ABD/TS/fl-S/ Date:

Relay & Window indications at Remote End:

Sr.

No.

Name of Line /

Equipment

W.I

.R

. L Remark

1.400 KV PRL-CHD-II L/O Trip for remote

fault, Main-I optd.Main-2 op:d. DirectCarrier fai ure

85 L/O -5 Flags

2.

400 KV PRL-LKD-11 CB Open, 3 pole trip,Carrier received

Breaker 409-186 & 286

Breaker 410-186,286,186X,286X

3.

400 KV PGC1L-I1 Main-1 Zone optd. Zone-1 optd. Distance-3.59km, Parli-2 Direct trip reedthrough Ch-1,CB open

4.

400 KV PGC1L-1 Zone-1 Trip Zone-1 R Y B trip,Distance-4.55 km

Tripped atPGCIL end

only.

PLCC Counter readings:

Direct Protection

Sr. Name of Line Local End Remote end

No. Before After Before After

I.

400 kV Parli- TX 1 42 43 43 43

Chandrapur RX 1 86 86 23 24

Ckt-2 TX 2 41 42 70 70

RX 2 67 67 38 39

2.

400 kV Parli- TX 1 05 06 08 08

Lonikand Ckt-2 RX 1 08 08 05 06

TX 2 04 05 08 08

RX 2 07 07 05 06

3.

400 kV Parli- TX 1 04 05 00 00

PGCIL Ckt-2 RX 1 00 00 04 05

TX 2 04 05 00 00

RX 2 00 00 04 05


Dr. Babaseheb Ambedkar Road,

f\r\s\ Old Power House Compound, Jublee Park, Aurangabad.IfflAHA KANbOU Phone:0240-2363317 E-mail: setccabdlfatimail.com.MaharayitraStaleEtecSnotyTranmsionCo.Ltd Fax: 0240-2355370 se2500(fl).mahatransco.in

RIGHT TO

INFORMATION

No. SE/TCC/ABD/TS//)- Date:

Sr.No. Name of Line Permissive

1.

400 kV Parli- Main-1 Main-2

PGCIL Ckt-2 Before After Before After

TX 1 0 1 0 1

A At Parli End RX 1 0 1 0 1

TX 2 0 1 0 1

RX 2 0 i 0 1

Sr.No. Name of Line Permissive

1.400 kV Parli- Channel-1 Channel-2

PGCIL Ckt-2 Before After Before After

Code TX 1 1 1 0 1

At -1 RX 1 1 1 0 1

B PGCIL Code TX 1 0 1 0 1

End -2 RX 1 0 1 0 1

Sequence of Restoration of 400 kV Bus-II:

Sr.

No.

Date Time Sequence of Restoration Remark

1.

09.07.2012 17:52 Hrs 400 KV PRL-LKD-II Shifted on Main Bus-I

2.

09.07.2012 19:28Hrs 400 KV PGCIL-1 Main Bus-11 charged throughPGCIL-I ckt.

3.

09.07.2012 19:40Hrs 400 KV BUSCOUPLER

4.

09.07.2012 20:42 Hrs 400/220KV ICT-II Charged from 220kV side buttripped on PDR. Charged on dt.

10.7.12 at 05:30hrs

5.

09.07.2012 20:53 Hrs 400/220KV ICT-I11

6.

09.07.2012 21:03Hrs 400 KV PRL-CHD-ll

7.

10.07.2012 08:43Hrs 400/220KV SPARE ICT

8.

13.07.2012 08:29Hrs 400 KV PGCIL-II Kept off due to systemconstraint.

Single Line Diagram :

Single line diagram of400 kV Bus at 400 kV Sub-station Girwali is attached herewith separately.

MAHATRAl ahafashlra State Eiectoty Transmission Co. Ltd,


Dr. Babasaheb Ambedkar Road,

Old Power House Compound, Jublee Park, Aurangabad.,vO Phone:0240-2363317 E-mail: [email protected].

Fax: 0240-2355370 [email protected]

No. SErrCC/ABD/TS/«-5/ Date;

RIGHT TO

'NFORMAT'ON

Analysis of Disturbance Records:Disturbance records from following relaying locations were available for analysis :1

. Busbar protection relay CSC-1502

. 400 kV Chandrapur circuit 1,2 & 33

.400 kV Lonikand ckt.2

4.

400/220/33 kV ICT 2 & 3

5. Powergrid circuit 1,2 -from both ends

Analysis of Disturbance Records has revealed following:

1. The busbar protection has operated for a bus zone 2 fault as operating current for A phase

exceeded 80% of restraining for that phase.2

. The busbar protection disturbance record shows presence of AC fault throughout the faultduration .

3. All the line and ICT at Girwali end fault records also show presence of AC fault in reverse

direction (i.e. towards bus) except the PowerGrid circuit 2.4

. The PowerGrid circuit 2 has extended Zone 1 tripping at both ends.5

. The PowerGrid circuit 2 &busbar protection records indicate presence of a fault involving busand line (A phase of bus and C phase of line).

6. The fault current recorded is @ 12000A

7. From the PowerGrid circuit I & 2 records some problems with respect to instrument

transformer secondary grounding were also suspected.8

. The disturbance records are also forwarded to ER for th|eir analysis and comments.

Onsite observations:

In view of this undersigned visited 400 kV Girwali. The onsite observations and informationreceived is as below:

1. On switchyard inspection; it is observed that in PowerGrid ckt 2 bay; the clearance between A

phase of main bus 2 and C phase of stub bus (line in effect) is less compared to other phases.A fault at this location can produce current distribution as seen in the disturbance records.

2. The PowerGrid engineers informed that the tripping of both PowerGrid circuits at their end in

Zone 1 was due to Zone 1 reach being set to 120% wrongly. The same is now corrected bythem.

3. It was observed that the instrument transformer grounding in Powergrid bays was carried on

relay panel side. Further tracing revealed that these panel side earthing strips get connected tocable trays in the cable gallery and not to the earth mesh directly. The connection point atcable trays shows some black markings.

4. This kind of earthing can create problems in relay measurement.

5. In PGCIL Ckt I & II the distance protections are connected to the CT cores with Knee Point

voltage 1000V and Bus bar protec;ion is connected to 4000V. This is not matching with theapproved drawings.

Conclusion:

The MSETCL protection operation is in order.

MAHATRANSCO(Maharashtra State Electncty Transmission Co. LW,



Phone: 0240-2363317 E-mail: setccabd 1 @gmail.com.Fax: 0240-2355370 se2500(a).mahatransco.in

RIGHT TO

,NFORMAT,ON

No. SErrCC/ABD/TS//i*7 Date:

Suspected Fault Location Diagram:

MAIN BUS 1

MAIN BUS 2/

I

AUX BUS

P 1

CB

O

(p o <b

LA

CVT

Cph

Bph

Aph

Cph

Bph

Aph

.Less clearance pointat

'

A'

ph of mam bus 2and '

C ph of stub bus

Cph

Bph

Aph

PGCIL 2 bay

P2

MAHATRANSCOl-lahsfashtra Stale Etectncty Tf3n$mi$$ioft Co. IM


Dr. Babasaheb Ambedkar Road,Old Power House Compound, Jublee Park, Aurangabad.Phone: 0240-2363317 E-mail: setccabd 1 (g!email.com.Fax: 0240-2355370 se2500@,mahatransco.in

RIGHT TO

,NFORMAT,ON

No. SE/TCC/ABD/TS/fl-5/ Date:

Corrective actions suggested:

1. Clearance measurement and applying necessary corrective action at the suspected fault

location.

2. The instrument transformer earthing n Power grid bays needs to be carried at instrument

transformer MBs as is the practice for all bays at this station.3

. The old panel earthing arrangement needs to be reviewed and properly connected.

Superintending Engineer,MSETCL, T&C Circle,

Aurangabad.O

Copy s.w.rs. to,1) The Chief Engineer, EHV CC O&M Zone, Aurangabad.

Copy f.w.cs. to,1) The Superintending Engineer, EHV O&M Circle, Parli-V.

Copy to,1) The Executive Engineer, Testing Div. Latur.

laharashtra Jtate Electricity Transmission Co. Ltd.Tesiinb . Communication Circle, Aurangabad 0

Jr. Babasaheb Ambedkar Road,Old Power, iouse Compound, Jublee Park, Aurangabad.Phone: 02 ,>)-2363317 E-mail: [email protected]: 0240 2355370 [email protected]

RIGHT TO

INFORMATION

BD/TS/A-5/35j Date: 18/07/12

,Ml

* t

i

W"'

C» Bii

in

EP If*

14-

EX

.t.

LL.f_SB »l "

SB ClW

>J4f-

11

i S i-Ts

D/TCC12/Occ.RT./400kV/400kVNK.2.02.12at 14:47

MAHARASHTRA STATE ELECTRICITY TRANSMISSION COMPANY LIMITED, Office of the Superintending Engineer, TCC, Karad.

PHONE: (O) 02164 - 255211 Testing & Communication Circle, (P) 02164 - 255155 Administrative Bldg, Ground Floor, FAX : (O) 02164 - 255118 At-Vijaynagar, Post - Supane. E-Mail:[email protected] Tal-Karad, Dist: Satara.– 415 114. Ref. No. : SE/TCC/KRD/T-93/297 Date: 21.07.2012 To, The Chief Engineer, TR (O&M), C.O. Prakashganga, Mumbai.

Sub: Occurrence Analysis Report for 220KV Mudshingi-I on dtd. 10.07.2012. In connection with above please find below the details of occurrence on 220KV Mudshingi-I on dtd. 10.07.2012

Name of the line :- 220 KV Mudshingi- I Date / Time of occurrence :- 10/07/2012 22:20 Hrs. Restoration Date & Time :- 11/07/2012 02:55 Hrs.

Window Indication

This End Remote End

Distance protection optd. Backup O/C-E/F prot. Optd, A/R blocked.

Distance protection optd. Backup O/C-E/F prot. Optd

Relay Indication

This End Remote End

186 A, 186B,186B. Micom P442:- Started phase AN, Ia=5.158KA,Ib=79.56A, Ic=53.63A, Fault in Zone= Zone 2, Fault location=12.51 Km.

R Ph Pickup Fault in zone= Zone 1, Fault location=3.3 KM.

Related Interruption:

1) 220 KV Talandge – Mudshingi II CB tripped from Mudshingi end on Zone 3 distance protection . 2) 220 KV Talandge – Tilwani -I CB tripped from Ichalkaranji end on Zone 3 distance protection. 3) 220 KV Talandge – Tilwani -II CB tripped from Ichlkaranji end on Zone 3 distance protection. 4) 220 KV Talandge – Sawantwadi CB tripped from Sawantwadi end on B/U Earth Fault.

5) 220 KV Tilwani – Miraj CB tripped from Miraj end on B/U Earth Fault.

Occurance Details: Due to mechanical problem in CB of 220 KV Talandge- Mudshingi Ckt- I, delayed operation of PDR & also problem in LBB, the remote end tripping of source feeders occurred.

Annexure-2.4(ii)

D/TCC12/Occ.RT./400kV/400kVNK.2.02.12at 14:47

Occurrence Analysis:

During testing on 13.07.2012 the following are the observations. PDR time lag found 500ms (AREVA Make) ‘R’ phase LBB element of 220 KV Talandge – Mudshingi Ckt- I was found faulty.

The timing of PDR is now kept 150ms & faulty LBB element is replaced. Encl.: SLD. Superintending Engineer Testing & Commn.Circle, Karad.

Copy S.W.Rs. to: 1) The Chief Engineer, EHV CC (O&M) Zone, Karad. Copy F.W.Cs. to: 1) The Superintending Engineer, EHV (O&M) Circle, Kolhapur. Copy to: 1) The Executive Engineer, Testing Division, Kolhapur. 2) The Executive Engineer, 400 KV R.S. Dn., Talandge.

M/F(T)

No. SE/T&C/NGP/Tech/ J1/423 Date: 22.08.2012 E-mail To The Chief Engineer Trans (O&M) C.O, MSETCL, Mumbai Sub:- Occurrence at 220 KV S/S Wardha on date 16.08.2012 ….. Analysis thereof

1. Name of the Substation : 220 KV S/S Wardha 2. Name of the Feeder / Equipment : 220 KV Khaparkheda

( 220 KV LBB protection operated) 3. Date & time of occurrence : 16.08.2012 at 00:45 Hrs 4. Date & time of restoration : 16.08.2012 at 01:43 Hrs 5 (A). Details of trippings at Local end : Name of feeder Time LED

indications Fault data Trip relays Window

indications Busbar protection relay type: RCS915)

00:45hrs BFP trip BB01, All lockout relays LEDs

1)Khaparkheda line 3ph LBB initiation. 2)Retrip to khaparkheda breaker at 100ms and final trip at 200ms. 3) Fault current = 10.77kA in Bph of khaparkheda line

96-lockout relays type CJX of all 13 -bays operated.

LBB protection optd.

220kV Khaparkheda line: Distance relay (7SA611 make: Siemens)

00:45hrs 1) Bph pickup, E pickup, Zone-1, Gen trip, Definitive trip. Carrier send 2) Bph OC CDD flag

Distance = 7.4km, Bph fault current=10.51kA

86B,186 Faulty annunciation scheme.

220kV Warora line

Nil Nil 186 Nil

220kV Bhugaon line

Nil Nil 186 Nil

220kV Abhijeet-1 line

Nil Nil 186 Nil

220kV Abhijeet-2 line

Nil Nil 186 Nil

220kV Yavatmal line

Nil Nil 186 Nil

50MVA 220/66KV ICT-1

Nil Nil 86 Nil

50MVA 220/66KV ICT-2

Nil Nil 86 Nil

220KV TSS-1 Nil Nil 86 Nil 220KV TSS-2 Nil Nil 86 Nil 220KV PGCIL deoli line

Nil Nil 186 Nil

220KV Dhamangaon line

Nil Nil 186 Nil

….2….

Annexure-2.4(iii)

….2….

6. Details of occurrence :

1. On dt.15.08.2012, 220 KV Wardha-Khaparkheda line (107 KM) tripped at @ 23:18 Hrs on distance protection from both end on following relay indications:

At Wardha end: At Khaparkheda end: Distance relay Make: Siemens Type:7SA611 Distance relay Type:7SA522 B pick up, E/F pick up B-ph, E/F, carrier receive Zone-1, General trip, A/R optd, Aided trip, A/R success Distance 85.5 KM, IL3=1.82 KA Distance -377 KM, IL3=9.93 KA B-ph trip relay 86B 2. The Ckt auto-reclosed at Khaparkheda end successfully. 3. At 220 KV Wardha S/S, B-ph trip command issued by the distance relay

(Make: Siemens Type:7SA611)of 220 KV Khaparkheda feeder and fault was isolated; A/R close command was issued to breaker but since B-pole closing coil was burnt, breaker did not close and finally tripped on PDR. A/R close command output contact of relay binary output damaged.

4. At 23:40 Hrs, trial taken by AE, shift incharge to charge the line through main breaker in local mode from yard but breaker did not close and again tripped on pole discrepancy.

5. Line was in charged condition from Khaparkheda end and charging current was about 40A which was normal. Hence it was decided to charge ckt through TBC.

6. At 00:45 Hrs, after carrying out necessary operation to shift 220 KV Khaparkheda ckt on TBC, TBC breaker closed. But immediately tripped with distance protection on B-ph,Z-1,General trip indication with distance 7.6 KM, IL3=10.51 KA, B-ph O/C relay, 86B, the operation of internal LBB feature of 220 KV Busbar protection (Make: NR electric, Type: RCS915) on indications as indicated under item (5) above.

7. Due to operation of LBB protection of 220 KV Khaparkheda feeder at Wardha S/S, all feeders connected to 220 KV bus including 220 KV Khaparkheda ckt tripped and 220 KV bus became dead.

8. Load @ 270 MW was affected due to above trippings. 9. At about 01:05 Hrs on dt.16.08.2012, 220 KV bus at 220 KV Wardha S/S charged from

220 KV Warora S/S and stood Ok. Normalcy of rest of the feeders and T/Fs except 220 KV Khaparkheda ckt restored one by one latest by 01:43 Hrs.

10. At about 06:04 Hrs, after replacement of closing coil of main breaker of 220 KV Khaparkheda Ckt and after taking trip-close trials of breaker, second trial of breaker with auto reclose OUT was taken but again tripped on distance protection on B-ph, Zone-1, General trip indication with distance=7.4 KM, IL3=10.32 KA and 3-ph trip relay 186. Breakdown was declared on line.

11. In line patrolling at location no.315 cut point, insulator string found burst and conductor found snapped. After attending line breakdown, the line charged on dt.16.08.2012 at 19:58 Hrs and stood OK.

Contd….

…3….. 12. Restoration of supply was done as given below:-

S. No.

Name of Sub-Station

Name of Feeder Time of restoration

Duration of Interruption

LBT (MW)

1 220 KV Wardha

220 KV Warora Ckt. 01:05Hrs 0:20 Hrs 131

2 220/66 KV,50 MVA T/F-I 1:35 Hrs 0:50 Hrs 15 3 220/66 KV,50 MVA T/F-II 01:39 Hrs 0:54 Hrs 17 4 220 KV Bhugaon Ckt 1:25 Hrs 0:40 Hrs 20 5 220 KV Abhijeet-I Ckt 01:20 Hrs 0:35 Hrs 32 6 220 KV Abhijeet-II Ckt 01:30 Hrs 0:45 Hrs 34 6 220 KV New Dhamangaon Ckt 01:34 Hrs 0:49 Hrs 61 7 220 KV PGCIL-Deoli Ckt 01:33 Hrs 0:48 Hrs 58 8 220 KV Khaperkheda Ckt 19:58 Hrs on

dt.16.08.2012 20:39 Hrs 29.79

9 220 KV TSS-II Ckt(on No Load) 01:15 Hrs 0:30 Hrs - 10 220 KV TSS-I Ckt 01:10 Hrs 0:25 Hrs 1.6 11 220 KV Yeotmal Ckt 1:32 Hrs 0:47 Hrs 175 12 66 KV Nagpur-I 1:40 Hrs 0:55 Hrs 0.96 13 66 KV Nagpur-II 1:41 Hrs 0:56 Hrs 5.05 14 66 KV Hinganghat-I 1:42 Hrs 0:57 Hrs 5.6 15 66 KV Hinganghat-II 1:43 Hrs 0:58 Hrs 6 16 66/11 KV 10 MVA T/F-I 1:36 Hrs 0:51 Hrs 2.7 17 66/11 KV 10 MVA T/F-II 1:37 Hrs 0:52 Hrs 4.4 18 66/11 KV 10 MVA T/F-III 1:38 Hrs 0:53 Hrs 3.2 13. Single line diagram showing the details of tripping is enclosed herewith for reference. 7. Analysis of occurrence : :

7. At 220 KV Wardha S/S, Single bus system (1 M+1 A bus arrangement) is provided for 220 KV bus.

8. On patrolling of line on dt.16.08.2012 at location no. 315 at cut point, B-ph string insulator found burst and conductor found snapped which created fault. Hence tripping of line on distance protection at both end is IN ORDER. Due to opening of conductor, fault was created towards wardha end.

9. The line auto-reclosed at 220 KV Khaparkheda S/S successfully. 10. At Wardha S/S due to burning of closing coil of B-ph pole of 220 KV Khaparkheda

feeder breaker, the line did not reclosed though the A/R command was initiated by distance relay and line tripped on PDR.

11. At about 00:44 Hrs, the line charged through TBC due to problem in main breaker. Due to persistent fault, distance protection and back up protection were operated but TBC breaker did not trip. Hence LBB protection of 220 KV Khaparkheda feeder operated (Internal feature of Busbar scheme).

Contd….

….4….

From the distance relay event log, it is observed that auto reclose was not disabled. Auto reclose gets disabled when N/T switch is shifted to ‘T’ position. This indicates that N/T switch was not shifted to ’T’ position before closing of the TBC breaker. As the N/T switch was not shifted to ‘T’ position, protection of Khaparkheda ckt was not transferred on TBC breaker, Hence trip command due to operation of distance protection and back up O/C relay was not extended to TBC breaker. Due to external LBB initiation through distance and back up protection to bus bar protection relay, re-trip command issued after 100 msec to Khaparkheda breaker from bus bar relay which was not extended to TBC breaker. Hence fault current was persisting. Thus internal LBB function of bus bar relay operated after 200 msec which issued final trip command to all breakers including TBC. About 10.77KA current in B_ph was recorded by busbar protection relay (Type:RCS915). Thus the operation of LBB protection is IN ORDER though undesired.

6. After replacement of closing coil, @ 06:04 Hrs line charged from wardha end but again tripped on distance protection B-ph, E/F,Z-1, distance=7.4 KM fault current 10.32 KA is correct as there was persistent fault on line.

8. Conclusion :

1) In first tripping line auto-reclosed from wardha end. Khaparkheda breaker Bph pole closing coil found burnt. Hence on auto reclose command B ph pole did not reclosed and breaker tripped on pole discrepancy. 2) While taking on TBC the NT switch was not got shifted properly to T position hence the tripping command at 00:44:27:642hrs was not extended to TBC breaker. 3) As the fault was persistent, which was eventually cleared by LBB protection.

9. Remedial Measures : 1. It is essential to wire up the closing interlock of N/T switch contact in remote closing of

TBC breaker where-ever it is not available. In the present case, it is not available in the scheme. Instructions have been issued to make necessary modification in the scheme.

2. Aux relay should be used in A/R reclose ckt where it is not available. Reclosing command is to be routed through contact of aux. relay.

Encl :-As above

Superintending Engineer

T& C Circle, MSETCL, NAGPUR.

T & C Circle, MSETCL, Nagpur

Details of occurrence at 220 KV Wardha S/S on dt 16.08.2012 at 00:45 Hrs

50 MVA220/66 KV

50 MVA220/66 KV

86 86,

220 KV TSS 1 220 KV TSS 2No load

86 86

220 KV PGCILDeoli

186

186,186,186

220 KVDhamangaon

186

220 KV Yavatmal

186,Distance 7.4 KM Z-1,B-ph, E/F,, If=10.51 KAB-ph O/C+LBB

186

Breaker TrippedBreaker did not trip

Note: Only relevant details shown

TF 1 TF 2

220 KV Abhijeet-II

220 KVAbhijeet-I

220 KVBhugaon

220 KVKhaparkhedaS/S

220 KVWarora

p O/C

Dist. 85.5 KM,B-N,A/R optd,IL3=1.82 KA

Detailed report on the occurrence on 22nd August 2012 at Khaparkheda - Maharshtra: At 09:40 Hrs, due to Y phase CT blast of 40 MVA station transformer-III there was smokes and fumes leading to conductive medium formation. This led to bus fault on 220kV Main Bus-I and initiate the tripping of all elements connected on Bus-I. This resulted in tripping of Khaparkheda Unit 1 and 3. Also at the same time due to flame failure Khaparkheda Unit 2 also tripped leading to a total generation loss of 397 MW. The antecedent conditions (at 09:39 Hrs) to the incident are given under:- 1. NEW Grid Frequency: 50.076 Hz. 2. WR Demand Catered: 29642 (Approximately.) 3. Net Inter Regional Export: 2599 MW Constituent-wise generation and demand details prior to the event (As per WRLDC SCADA data) at 09:39 Hrs:

WR Constituents

Demand(in MW)

Generation (MW)

Thermal and Gas


Gujarat 10041 6781 469 - 675 117

Maharashtra 12895 5409 1952 - N/A N/A Madhya Pradesh

3490 794 1285 - - -

Chhattisgarh 2180 1464 120 - - - Goa 239 0 0 - - - DD 198 0 0 - - - DNH 599 0 0 - - - ISGS -- 10671 1269 1235 - -

Total 29642 25119 5095 1235 675 117


1 220 kV Khaparkheda- Ambazari- I 92

2 220 kV Khaparkheda- Ambaazri- II 64

3 220 kV Khaparkheda- Kanhan-I N/A

4 220 kV Khaparkheda- Kanhan- II 73

5 220kV Khaparkheda-Koradi 67

6 220 kV Khaparkheda- Kalmeshwar N/A

7 220 kV Khaparkheda- Wardha N/A

8 220 kV Khaparkheda –Khaparkheda New –I 30

9 220 kV Khaparkheda- Khaparkheda New -II N/A

10 220 kV Khaparkheda- Kaulewada- I 31

11 220 kV Khapakheda - Kaulewada - II 31

12 40 MVA Station T/F I 6

Annexure-2.4(iv)

13 40 MVA Station T/F Iii 8




MW) *

1 Unit 1 210 139

2 Unit 2 210 112

3 Unit 3 210 138

4 Unit 4 210 162

*As per WRLDC SCADA data. Event Overview: At 09:42 Hrs

• 40 MVA Station Transformer-III was connected to 200 kV Main Bus-I on differential and backup protection.

• Y-Phase CT bursting of this T/F led to smokes and fumes which created conductive media and resulted in 220 kV Main Bus-I fault .This led to operation of bus bar protection of Main Bus-I which caused the tripping of all connected feeder as well as the bus coupler.

• Unit 1 and 3 tripped due to operation of bus bas protection.

• Due to flow of zero sequence current through the 220 kV side CTs of 400/220/33kV 500 MVA ICT-2 at 400 kV Khaparkheda S/S, ICT-2 tripped on Y & B Phase differential protection. This was due to the dual side earthing of 220 kV CTs which provided the conducting path to zero sequence current.

• Unit-2 which was on Main bus-2 is has tripped during the occurrence due to flame failure and not due to operation of any electrical protection.

The sequence of tripping and restoration at Khaparkheda is given under as per the data retrieved from WRLDC SCADA and MSETCL.

Sl No.



Time of Restoration

(hh:mm)


1 220 kV Main Bus-1 9:40:35.398 10:36 Bus Bar Protection 2 40 MVA Station T/F 3 9:40:35.416 21:22 E/F Operated,MTR 3 220 kV Khaparkheda-Koradi 9:40:35.421 11:04 Bus Bar Protection 4 220 kV Khaparkheda-Kanhan II 9:40:35.432 14:35 Bus Bar Protection 5 Khaparkheda Unit 1 9:40:35.436 14:29 6 220 kV Khaparkheda-

Kalmeshwar 9:40:35.438 13:52 Bus Bar Protection

7 Khaparkheda Unit 3 9:40:35.450 20:30 8 220 kV Khaparkheda-New

Khaparkheda-I 9:40:35:458 10:55 Bus Bar Protection

9 40 MVA Station T/F 1 9:40:35.472 10:42 MTR Operated 10 220 kV Khaparkheda- 9:40:36.492 16:20 Bus Bar Protection

Kaulewada-I 11 220 kV Khaparkheda-Ambazari-I 9:40:37:170 14:46 Bus Bar Protection 12 Khaparkheda Unit 2 9:40:44.928 12:36 MTR Operated 13 400/220/33 kV 500 MVA ICT-II 09:40 Out MTR Operated

*As per MSETCL Load / Generation affected: The generation loss due to tripping of Khaparkheda unit 1, 2 and 3 was 397 MW (*As per MSETCL). No load loss occurred during the event as the loads (362 MW) were thrown on other S/Ss. Frequency Change : With the loss of generation ,frequency dipped by 0.162 Hz ( i.e. from 50.042hz to 49.880 Hz). Restoration: Restoration work started with charging Bus-I by closing Bus coupler from Bus-II. After that lines and units were taken in service one by one. Complete restoration took 11 hours and practice should be to reduce this time. Analysis : The tripping of Unit-2 was not desired and MAHAGENCO should investigate in this matter.Also the tripping of 500 MVA 400/220/33 kV ICT-2 due to was not desirable.So,in future it should be taken care when ICTs are out ,the earthing switch is to remain open. Graphical plot:


Fig2 . Change in Maharashtra demand with units tripping

Fig3 . Change in Western Region demand with units tripping


Remarks: The bus fault is very severe to the system and may lead to cascade tripping. So, the practice should be to carry out the diagnostic test of equipments regularly and maintenance schedule should be followed strictly.

(Abhimanyu Gartia)

Dy. General Manager (OS & SS)

116PCM ANNEXURE-3

1 400kV Khaparkheda 400kV Kh,kheda-Ch,pur and KoradiLines

MSETCL (Y)

01-08-2012 23:10 03-08-2012 17:30 i) Due to bursting of 400kV r-Ph CT of 400kV Ch,pur. ii) The 400kV Koradi-II bay is adjacent to 400kV Ch,pur bay . Effect of flashover and smoke created fault and damage to B-Ph tie CT of Koradi-II bay between Tie CT and 86B Isolator,Hence teed 2 protection for Koradi-Ii operated..

2 400kV Chandrapur 400kV Ch,pur-Parli-3 MSETCL (Y)

02-08-2012 09:42 02-08-2012 11:50 Line tripprd at Parli end and L/O trip for remote faultat Ch,pur end on receipt of DT signal.

3 400kV Khaparkheda 400kV Kh,kheda-Koradi Lines

MSETCL (Y)

06-08-2012 02:42 06-08-2012 11:23 At 400kV k,kheda S/S, 400kV Koradi ckt tripped due to receipt of DT signal from Koradi.

4 400kV Koradi 400kV Koradi-Akola MSETCL (Y)

13-08-2012 17:40 13-08-2012 18:09 Ckt tripped at Koradi end on receipt of DT signal from suspected problem in PLCC panel at 400KV Akola S/S under Amravati Zone.

5 400kV Chandrapur 400kV Ch,pur-PGCILCkt-1

MSETCL (Y)

22-08-2012 11:20 30-08-2012 12:34 O/V stage -1 operated at GCR end.Y-Ph CVT suspected giving higher O/V at GCR end, replaced by availing outage and line recharged at 12:34 Hrs on 30.08.12(Line maintained by PGCIL)


24-08-2012 16:18 24-08-2012 16:25 Ckt tripped at Koradi end on receipt of DT signal from Akola end.suspected problem in PLCC panel at 400KV Akola S/S under Amravati Zone.

7 400kV Koradi 400kV Koradi-Sarani MSETCL (Y)

25-08-2012 23:10 25-08-2012 23:34 Ckt tripped at Koradi end on receipt of DT signal Sarani end.


05-09-2012 00:27 06-09-2012 07:21 O/V stage 1 operated at Akola end .L/O trip for remote end fault at Koradi end on receipt of DT signal.

9 400kV Koradi 400kV Koradi-K,khedaCkt-1

MSETCL (Y)

05-09-2012 07:30 06-09-2012 06:51 O/V stage 1 operated at Koradi end .L/O trip for remote end fault at K,kheda end on receipt of DT signal.

10 400kV Koradi 400kV Koradi-K,khedaCkt-2

MSETCL (Y)

05-09-2012 07:30 06-09-2012 06:14 O/V stage 1 operated at Koradi end .L/O trip for remote end fault at K,kheda end on receipt of DT signal.

11 400kV Koradi 400kV Koradi-Bhilai MSETCL (Y)

05-09-2012 04:18 05-09-2012 10:53 Inetially line tripped on reactor winding Temp high due to shorting/damage of TB.By passing above feature line recharged but tripped on O/V at both ends.The faulty replaced . Winding Temp high received due to shorting of TB on MB. There was no actual rise in Windg temp.(Bay/lines maintained by PGCIL)

12 400kV Khaparkheda 400kV Kh,kheda-Ch,pur

MSETCL (Y)

06-09-2012 02:35 06-09-2012 06:29 O/V stage 1 operated at K,kheda end .L/O trip for remote end fault at Ch.pur end on receipt of DT signal.

13 400kV Chandrapur 400kV Ch,pur-Parli-2 MSETCL (Y)

09-09-2012 17:31 10-09-2012 07:07 Transient R-N fault . It is reported that lightening stroke observed between Loc No.35-36 during tripping.


11-09-2012 03:36 11-09-2012 05:15 O/V stage 1 operated at Koradi end .L/O trip for remote end fault at Sarani end on receipt of DT signal.

15 400kV Koradi 400kV Koradi-IndiaBulls

MSETCL (Y)

04-10-2012 16:50 04-10-2012 17:19 Ckt tripped at Koradi end due to L/O trip for remote end fault on the receipt of DT signal from remote end.(Newly commissioned Line)


26-10-2012 13:55 26-10-2012 14:18 Transient Y-n fault .line A/R successfully at Koradi end and tripped at sarani end.(PGCIL Line)

17 400kV Bhilai 400KV Bhilai-Koradi

CSPTCL (Y)

05-09-2012 04:18 05-09-2012 10:56 Line tripped from both ends due to problem in Reactor at Koradi end.

18 400kV Bhilai 400KV Bhilai-Korba(W) Bank

CSPTCL (Y)

09-09-2012 12:15 09-09-2012 12:44 Line tripped from both ends due to normal tripping.

19 400kV Bhilai 400KV Bhilai- Ch,pur CSPTCL (Y)

29-09-2012 23:08 30-09-2012 10:17 Line tripped from both ends due to Over Voltage.

20 400kV Satpura S/S 400kV Sarani-Itarsi MPPGCL (Y)

02-08-2012 13:42 02-08-2012 18:28 Line tripped from both ends due to Over Voltage.

21 400kV Satpura S/S 400kV Sarani-Seoni MPPGCL (Y)

04-08-2012 22:45 04-08-2012 23:42 Line tripped on Bus Bar Diff zone-2, due to Sarni ISP Line C.B failure.

22 400kV Satpura S/S 400/220kV ICT MPPGCL (Y)

06-08-2012 04:52 06-08-2012 12:00 ICT tripped from both sides, due to fault at 220kV side B-Phof GT unit-3

23 400kV Satpura S/S 400kV Sarani-Koradi MPPGCL (Y)

07-08-2012 13:05 07-08-2012 14:20 Sarani end C.B tripped due to receipt of false DT code-3 from Sarani end carrier Panel.


07-08-2012 13:55 07-08-2012 19:07 Line tripped on C.B. pole discripency at Sarani end .Seoni end C.B. hand tripped . On checking Y-Ph C.B. Grp-A trip Ckt cable found faulty and short.The same was replaced.


25-08-2012 23:10 25-08-2012 23:34 Koradi end C.B tripped due to receipt of false DT code-3 from Sarani end carrier Panel.


11-09-2012 03:35 11-09-2012 05:15 Line tripped on receipt of DT from remote end,due to Koradi end O/V protection operated.


14-09-2012 18:59 14-09-2012 20:25 Only Seoni end C.B. tripped on O/V protection due to system disturbance at Sipat S/S.However Sarani end C.B. did not trip due to non reciept of DT code-1,owing to PLCC panel probleb.at Seoni end. Sarani end C.B. hand tripped.

28 400 KV Birsinghpur 400KV Bir-Katni MPPGCL (Y)

19-11-2012 19:33 _ _ The Line tripped at DEF on Y-Ph fault at 16.71 Kms from BRS end.

29 220kV TAPS 220kV TAPS-Vapi NPCIL (Y)

02-07-2012 13:05 02-07-2012 21:04 Transient Fault.

30 220kV TAPS 220kV TAPS-Borivali NPCIL (Y)

25-08-2012 12:51 25-08-2012 13:28 Transient Fault.

31 220kV TAPS 220kV TAPS-Bhilad NPCIL (Y)

30-08-2012 12:29 30-08-2012 13:10 Transient Fault.

32 220kV TAPS 220kV TAPS-Borivali NPCIL (Y)

02-10-2012 03:14 02-10-2012 14:08 Transient Fault.

Page1

(1) TRIPPINGS OF LINES / ICTS of MSETCL,CSPTCL,MPPGCL & NPCIL

33 400kV Mundra 400kV Mumndra-Limbdi#2

PGCILL (Y)

02-07-2012 04:20 02-07-2012 05:00 A/T on B‐N fault (foggy conditions in the salty area of Rann of Kutch)


PGCILL (Y)

02-07-2012 05:50 02-07-2012 05:53 A/T on Y‐N fault (foggy conditions in the salty area of Rann of Kutch)

35 400kV Mundra 400kV Mumndra-Bachau#1

PGCILL (Y)

02-07-2012 05:53 04-07-2012 01:24 A/T due to Bus Bar Protection Operation at Mundra end.

36 400kV Shujalpur 400kV Shujalpur-Nagda#1

PGCILL (Y)

03-07-2012 14:36 03-07-2012 14:36 A/R on R‐N fault.

37 400kV Damoh 400kV Damoh-Birsinghpur#2

PGCILL (Y)

03-07-2012 15:09 04-07-2012 16:21 A/T on Failure of B‐ph LA at Birsingpur (MPPTCL S/S).

38 400kV Gandhar 400kV Gandhar-Dehgam#1

PGCILL (Y)

03-07-2012 22:56 03-07-2012 22:56 A/R on B‐N fault.


PGCILL (Y)

03-07-2012 23:13 04-07-2012 18:00 A/T on Y‐N fault(Insulator string failure)

40 400kV Mundra 400kV Mundra-Bachau#1

PGCILL (Y)

04-07-2012 01:42 06-07-2012 12:44 A/T due to Bus Bar Protection Operation at Mundra CGPL.

41 400kV Mundra 400kV Mundra-Limbdi#1

PGCILL (Y)


42 400kV Bhachau 220kV Bachau-Ranch,pura#1

PGCILL (Y)


43 400kV Vindhyachal 400kV Vindhyachal-Jabalpur#2

PGCILL (Y)

05-07-2012 05:08 05-07-2012 05:08 A/R on Y‐N fault.


PGCILL (Y)

07-07-2012 07:46 07-07-2012 08:48 A/T on R‐N fault (foggy conditions in the salty area of Rann of Kutch)

45 400kV Indore 40kV Indore-Asoj#2 PGCILL (Y)

07-07-2012 16:37 08-07-2012 10:22 A/T on R‐N fault (Insulator Flashover)

46 400kV Khandwa 400kV Khandwa-Dhule#1

PGCILL (Y)

13-07-2012 05:12 13-07-2012 05:12 A/R on Y‐N fault.

47 400/220kV ICT BinaS/S

400/220kV ICT-1 PGCILL (Y)

13-07-2012 16:06 06-08-2012 22:38 A/T on operation of Bucholz & PRV

48 400kV Satna 40kV Satna-Bina PGCILL (Y)

23-07-2012 12:27 23-07-2012 12:27 A/R on Y‐N fault


PGCILL (Y)

24-07-2012 03:23 24-07-2012 08:24 A/T on Y‐B‐N fault (foggy conditions in the salty area of Rann of Kutch)


PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)

27-07-2012 06:23 27-07-2012 08:57 A/T on R‐Y‐B fault (foggy conditions in the salty area of Rann of Kutch)


PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)


61 400kV Itarsi 400kV Itarsi-Indore#2 PGCILL (Y)

29-07-2012 13:43 29-07-2012 19:44 A/T on R‐N fault (failure of E/W mid span Joint)


PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)

31-07-2012 02:33 31-07-2012 08:19 A/T on R‐Y‐N fault (foggy conditions in the salty area of Rann of Kutch)


PGCILL (Y)



PGCILL (Y)


70 400kV Bachau 400kV Bachau-Ranchodpura#1

PGCILL (Y)



PGCILL (Y)


Page2

(2) TRIPPINGS OF LINES / ICTS of PGCIL

72 400kV Baghau 400kV Bachau-Ranchodpura#1

PGCILL (Y)



04-08-2012 19:31 05-08-2012 12:26 A/T on R‐N fault (Insulator flash over).


PGCILL (Y)

05-08-2012 04:09 05-08-2012 12:27 A/T on receipt of DT from Mundra end


PGCILL (Y)



PGCILL (Y)



PGCILL (Y)



PGCILL (Y)

06-08-2012 05:42 06-08-2012 05:42 A/R on B‐N fault.


PGCILL (Y)



PGCILL (Y)


81 400kV Khandwa 40kV Khandwa-Dhule#2

PGCILL (Y)

07-08-2012 05:57 07-08-2012 05:57 A/R on Y‐N fault.


PGCILL (Y)

08-08-2012 04:15 08-08-2012 22:33 A/T on R‐Y fault (foggy conditions in the salty area of Rann of Kutch)


PGCILL (Y)

08-08-2012 04:15 08-08-2012 09:28 A/T on B‐R fault (foggy conditions in the salty area of Rann of Kutch)

84 400kV Satna 40kV Satna-Bina#2 PGCILL (Y)

08-08-2012 10:14 09-08-2012 10:14 A/T on B‐N fault (Insulator string failure)


08-08-2012 23:13 09-08-2012 13:53 A/T on B‐N fault (Insulator string failure)


PGCILL (Y)



PGCILL (Y)



PGCILL (Y)

10-08-2012 04:07 10-08-2012 08:38 A/T on Y‐B‐N fault (foggy conditions in the salty area of Rann of Kutch)


PGCILL (Y)



PGCILL (Y)


91 400/220kV ICT BinaS/S

400/220kV ICT-1 PGCILL (Y)

20-08-2012 14:30 21-08-2012 02:13 ICT A/T on operation on differential protection due to failure of 33kV Y‐ph LA.


21-08-2012 14:29 22-08-2012 09:40 A/T on B‐N fault. (B‐ph inner string failure)


PGCILL (Y)

22-08-2012 16:47 22-08-2012 21:00 A/T on R‐B fault


PGCILL (Y)

23-08-2012 09:19 23-08-2012 14:07 A/T on R‐B fault (Jumper snapping)


29-08-2012 08:50 29-08-2012 17:40 A/T on Y‐N fault.(Persisting fault)


PGCILL (Y)

07-09-2012 11:05 07-09-2012 15:09 A/T on R‐Y fault (Jumper failure)


PGCILL (Y)

11-09-2012 19:05 11-09-2012 19:44 A/T on R‐B fault.

98 400kV Bina 400kV Bina-Sujalpur#2 PGCILL (Y)

16-09-2012 04:40 16-09-2012 05:00 A/T at Bina end only on D/T received due to BPL PLCC mal operation.


22-09-2012 17:51 22-09-2012 10:55 A/T on Y‐N fault (Insulator String failure)


PGCILL (Y)

23-09-2012 17:59 23-09-2012 02:13 A/T on DT receipt due to reactor protection optd at V'chal end.


PGCILL (Y)

24-09-2012 12:01 24-09-2012 18:32 A/T due to failure of B‐Ph LA at JBP end.


26-09-2012 10:51 26-09-2012 21:56 A/T on B‐N fault (Insulator falshover)

103 400kV Bina 400kV Bina-Sujalpur#1 PGCILL (Y)

01-10-2012 22:55 01-10-2012 23:05 A/T due to operation of Reactor Protection at Sujalpur S/S.

104 400kV Satna 400kV satna-Bina#2 PGCILL (Y)

11-10-2012 17:51 11-10-2012 10:24 A/T on B‐N fault (Insulator flashover)

105 400kV Vindhyachal 400kV Vindhyachal-Satna#3

PGCILL (Y)

14-10-2012 12:57 14-10-2012 13:51 A/T on B‐N fault.(Persisting fault)

106 400kV Jabalpur 400kV Jab,pur-Itarsi#3 PGCILL (Y)

20-10-2012 03:02 20-10-2012 03:02 A/R on R‐N fault.

107 400kV Bachau 400kV Bachau-Ran,pura#1

PGCILL (Y)

29-10-2012 13:42 29-10-2012 13:42 A/R on B‐N fault


09-11-2012 04:00 09-11-2012 04:15 A/T on Y‐N fault.(Persisting fault)

109 400kV Mundra 400kV Mundra-Bachau#1

PGCILL (Y)

10-11-2012 12:00 10-11-2012 12:22 A/T on receipt of Direct Trip signal from CGPL Mundra end (BPL PLCC mal operation).

110 400kV Gandhar 400kV Gandhar-Navsari#1

PGCILL (Y)

19-11-2012 12:02 19-11-2012 12:40 A/T on R‐N fault (Sugarcane Burning)

111 400kV Gandhar 400kV Gandhar-Navsari#2

PGCILL (Y)

19-11-2012 12:02 19-11-2012 12:49 A/T on B‐N fault (Sugarcane Burning)

112 400kV Vindhyachal 400kV Vindhyachal-Satna#4

PGCILL (Y)

30-11-2012 00:32 30-11-2012 01:57 A/T on operation of Reactor Protection at Satna S/S.

Page3

Status of implementation in WR on Recommendations of Report on Grid disturbance on 30th and 31st July as on 9.01.2013 No. Time Subject/Description Action taken

Frame 9.1.1 1 Year There is a need to review protection schemes. This

Committee concurs with recommendation of previous enquiry committees that a thorough third partyprotection audit need to be carried out in time boundmanner. This exercise should be repeated periodically and monitored by RPCs.

RPCs, CTU, STUsGETCO: Completed all 400 kV s/s in 2010 through M/s Voltech Engg.-9 s/s MSETCL : Through CPTI, PRDC or other agency; in process for around 15 s/s in Jan-13 NTPC : Completed MPPTCL : Group formed PGCIL : 1 s/s at Bina completed CSPTCL : To be taken up shortly WRPC : letter sent to all STUs asking for nominations for forming revolving group; to be discussed in 116th PCM in January-2013.

9.1.2 Immediate Till protection audit is taken up, there is need to take immediate review of zone-3 philosophy in particular. Techniques are available to modify characteristics of the relay so that it can distinguish between load encroachment and faults. These techniques and other alternatives should be explored immediately.

RPCs, CTU, STUsPower Swing MSETCL : All zones blocked for 2 Sec NTPC : All zones blocked for 2 Sec GETCO :zone-3 blocked as per CBIP 274 manual Load Encroachment Approach (i) Distinguishing between load and line angle (ii) Distinguishing between fault by sensing zero sequence

component WRPC : After detailed deliberation, it was observed that utilities have different make numerical relays therefore option were given to STUs to adopt any of above methodologies and intimate the action/status of the same

9.1.3 1 year The application of synchrophasor measurements fromPMUs should be explored for protection systems. There is also an urgent need to deploy Special Protection System (SPS) in critical transmission elements. Also there is need to make already approved SPS operational.

RPCs, CTUPMUs under pilot project installed at Raipur, Bhadravati, Jabalpur, Itarsi. PMUs at KSTPS, VSTPS and SSTPS is planned to be installed by WRLDC as discussed in the meeting held on 21.09.12. In Maharashtra 17 PMUs have been installed. URTDSM is being implemented by PGCIL. It is decided to procure 30% of PMU through indigenous sources as agreed in 35th SCM of WR.

9.1.4 1 Month A complete independent audit of time synchronization ofDRs, ELs and PMUs should be carried out

Generators, CTU, STUs Status of time synchronization awaited from STUs

9.2.1 1 Month Frequency band needs to be further tightened andbrought close to 50 Hz. POSOCO may file an urgency application in Supreme Court for early resolution of the issue in view of the recent grid disturbances.

POSOCO

9.2.2 3 months A review of UI mechanism should be carried out in viewof its impact on recent grid disturbances. Frequency control through UI may be phased out in a time bound manner and Generation reserves/Ancillary services may be used for frequency control. Appropriate regulatory mechanism needs to be put in place for this purpose.POSOCO should take up the matter with CERC

POSOCO

9.3 Immediate All STUs should immediately enable under frequencyand df/dt based load shedding schemes. Central Commission should explore ways and means for implementation of various regulations issued under theElectricity Act, 2003. Any violation of these regulations can prove to be costly as has been the case this time.RPCs need to take up the matter for compliance. In case non-compliance persists, POSOCO should approach Central Commission.

STUs, RPCs, POSOCORevised UFR and df/dt scheme implemented by all utilities. In case of WR getting isolated from rest of NEW grid to arrest high frequency operation and unplanned unit tripping few units have been identified for planned tripping at 51.5 Hz.

9.4 3 months All out efforts should be made to implement provisionsof IEGC with regard to governor action. Central Commission needs to look into ways and means to hasten implementation of provisions of IEGC including that on governor action. POSOCO need to take up thematter with Central Commission

POSOCO191-No. of units eligible for RGMO 73- No. of units confirmed 13- No. of units exemption applied 109- No. of units in various utilities are yet to be made to participate in the RGMO

9.5.1 1 month POSOCO should take up with Central Commission theissue of inconsistency between Congestion regulation and the detailed procedure framed there under so thatcongestion due to forced outages and UnscheduledInterchange (UI) can be handled effectively

POSOCO

9.5.2 6 months NLDC and each RLDC should have one real-timesecurity desk in all the shifts to be manned by engineer capable of carrying out TTC calculations. To facilitatethis, manpower at NLDC and RLDCs need to beenhanced with regulatory support to take care of financial aspects. Till this arrangement can be firmed up, various scenarios of outages could be built, which then can be used by despatcher in real time. Faster algorithm for calculation of TTC may be adopted by the load despatchers to update it in real time under outage

conditions.

POSOCO

9.6 Immediate Outage planning of inter-State and inter-regionaltransmission elements should be carried out in a coordinated manner at RPC fora (say Operation Co- ordination sub-committee of RPCs) in accordance with regulation 5 of Central Electricity Authority (Grid Standards) Regulation, 2010 and Section 5.7.1 of Indian Electricity Grid Code. In case need for emergency maintenance arises in between two meeting of Operation Co-ordination sub-committee, NLDC and RLDCs should allow such maintenance after carefully looking at prevailing system conditions under intimation to RPC

Secretariat

RPCs Already discussed and agreed in OCC of WRPC. 1. Interstate lines are coordinated by RPC/RLDC in monthly OCCs 2. Interregional lines are coordinated by NLDC in consultation with RPCs/RLDCs This is implemented and being regularly monitored in OCCs of WRPC.

9.7 6 months In order to avoid frequent outages/opening of lines underover voltages and also providing voltage support under steady state and dynamic conditions, installation of adequate static and dynamic reactive power compensators should be planned.

CEA, CTU, STUs10+17 reactors in various locations planned in WR and under various stages of implementation by PGCIL/GETCO/MSETCL. In 35th SCM, SATCOM which is modern technique for compensation of reactive power approved at six locations in WR.

9.8 6 months The powers of Load Despatch Centres and Regulatory Commissions related to non-compliance of statutory/regulatory provisions including that for non- compliance of directions and non-payment of UI charges, need review. Appropriate amendments need to be carried out in the Electricity Act, 2003 after such review.

Ministry of Power, Govt. of India

9.9.1 Immediate The regulatory provisions regarding absorption ofreactive power by generating units needs to be implemented

POSOCO

9.9.2 6 months An audit of devices such as HVDC, TCSC, SVC andPSS should be done immediately to ensure that their stability features are enabled. Further, exercise of PSStuning should be planned and implemented. Settings of these dynamic stabilizing devices should be reviewed at appropriate intervals

CTU, STUs, Generators23 generators PSS tuning completed. Telemetry data from TCSC/FSC not available to RLDC.

9.9.3 Immediate Functioning of existing PMUs and availability of theiroutput to RLDCs and accuracy of time synchronization should be monitored on daily basis and, if required, corrective actions should be taken on priority basis

CTU, POSOCOAll PMUs are working. Time synchronization issue.

9.10.1 1 year The synchrophasor based WAMS employing PMUsoffer a wide applications for real time monitoring andcontrol of the system, specially under the dynamic conditions. Adequate number of PMUs should be installed to improve the visibility and real time monitoring of the system. Further the applications related to the synchrophasor based wide area monitoring, protection and control should be embedded in the system

CTU PMUs on pilot project installed at Raipur, Bhadravati, Jabalpur, Itarsi. PMUs at KSTPS, VSTPS and SSTPS is planned to be installed by WRLDC as discussed in the meeting held on 21.09.12 to discuss occurrence at Sipat on 14.09.12. URTDSM is being implemented by CEA.

9.10.2 1 year Possibility of voltage collapse prediction, sensing globalpower system conditions derived from local measurements may be explored

RPCs A-eberle Relay installed at 400 kV Boisar (PG) s/s. In 110th PCM proposed at Jetpur, Bhilai, Aurangabad, Indore and Ponda s/s

9.11 6 months In order to assess the system security in real time andassess the vulnerability condition of the system, dynamic security assessment need to be periodically carried out at the control centers. A proper review and upgradation of the state estimation procedure is required to improve the visibility and situational awareness of the system

POSOCO

9.12 Efforts should be made to design islanding scheme basedon frequency sensing relays so that in case of imminent grid failure, electrical islands can be formed. These electrical islands can not only help in maintaining supply to essential services but would also help in fasterrestoration of grid

CEA, RPCs, POWERGRID, STUs, SLDCs andGenerators 1.Mumbai, Ahmedabad , GTPS uran islanding schemes functional at present 2. Scheme for Bhopal city/ Bina Traction/JP Bina Power stn is under development. 3. All CPPs are planned for islanding at a lower frequency

than 48.8 hz i.e. final stage of UFR setting so that these stations are available for startup power.

4. APL-SPS, LANCO-SPS is already there. SPS for Agra- Gwalior, Zerda-Kankroli, Badod-Modak is planned. Units to be backed down in WR have been identified.

9.13.1 1 year As National Grid is on the horizon, homogenization of Govt. of India, State Govts system operation philosophy is need of the hour. The present organizational set up of Load Despatch Centres need to be reviewed. System operation needs to be entrusted to Independent System Operator (ISO). In addition, SLDCs should be reinforced and ring fenced for ensuring functional autonomy 9.13.2 3 months Training and certification of system operators need to be Govt. of India, State Govts

given focused attention. Sufficient financial incentives need to be given to certified system operators so that system operation gets recognized as specialized activity

9.14 2 years Intra-State transmission system needs to be planned andstrengthened in a better way to avoid problems of frequent congestion

STUs

9.15.1 6 months Appropriate amendments should be carried out in Grid CEA Connectivity Standards to restrain connectivity of a generating station or a transmission element without required communication and telemetry facilities. 9.15.2 1 year The Communication network should be strengthened by

putting fibre optic communication system. Further, theCommunication network should be maintained properly to ensure reliability of data at Load Despatch Cenres

CTU and STUsApprovals by WRPC

• Addl. 2672 Kms of OPGW, 14kms of OFC along with wideband communication equipment of adequate capacity for setting up of back-up SLDC at Govindpura, Bhopal, connectivity of Sub-LDC Gandhinagar and Sub-LDC Jetpur to SLDC Vadodara (Gotri) on OFC with suitable end equipments.

• Existing communication equipments (SDH 37nos. & PDH 72nos.) to be replaced at the cost of 3.89 crores

• Installation of PABX System at SLDCs of Western Regions, WRLDC and NLDC

9.15.3 3 months RTUs and communication equipments should have CTU and STUs

uninterrupted power supply with proper battery backup so that in case of total power failure, supervisory control and data acquisition channels do not fail 9.15.4 6 months In case of existing generating stations or transmission RPCs, POSOCO

elements without telemetry facility, the same should be New stations are mandated for data transmission through put in place at the earliest. If prolonged operation telemetry before commissioning. without telemetry continues, POSOCO should approach Central Commission

9.16 1 year Large variations are observed in time taken for initiationof unit start up (Boiler light up) by the stations afteravailability of start-up power and also for start ups/light up of subsequent units. While subsequent start-ups were very fast (10-20 minutes) in some of the units, in other cases they took considerably longer time – several hours. Reasons for the delays in attempting first start-up andsubsequent start-ups may be examined by the utilities in consultation with CEA. A standard procedure for preparatory activities and sequence of start up may beput in place by the stations to restore units as early aspossible particularly in contingencies.

CEA, Generating Utilities and RLDCs

9.17 3 months At inter-State level, the entire landscape has changed CEA over past few years. With de-licensing of generation and provision of open access in Electricity Act, 2003 and development of organized electricity markets, lot of generation is coming in the form of merchant generation. Four out of the five regions have been integrated and formation of National Grid is on the horizon. Under such scenario, there is need review the Transmission Planning criteria. 9.18 1 year There is need to reinforce system study groups in power

sector organisations to analyse the system behaviour under different network status/ tripping of lines/outageof generators. Where these do not exist, these should be created

CEA, CTU and STU

9.19 1 month It was felt that a separate task force may be formed,involving experts from academics, power utilities and system operators, to carry out a detailed analysis of the present grid conditions and anticipated scenarios which might lead to any such disturbances in future. The committee may identify medium and long term corrective measures as well as technological solutions to improve the health of the grid

MOP, CEA

9.20 1 year For smooth operation of grid systems, it is absolutelyimportant that all the power generating and distributing stations are connected on a very reliable telecom network. (i) A proper network may be built up preferably using MPLS(multy protocol label switching) which is simple, cost effective and reliable. In remote place where connectivity is a problem, the stations can use dedicated fibre cable from the nearest node (ii) Since POWERGRID has its own fibre optic cables, practically covering all major nodes and power stations, a proper communication/IT network may be built using dedicated fibres to avoid any cyber attach on the power system.

CTUs, STUs

116 pcm agenda mail list - wrpcwrpc.gov.in/pcm/116pcm_agenda.pdf · 116 pcm agenda mail list 1)...

Documents