Agenda 123 PCM PDF
Agenda 123 PCM PDF
Agenda 123 PCM PDF
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government of India
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Central Electricity Authority
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Western Regional Power Committee IS/ISO: 9001-2008
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F-3, MIDC Area, Andheri (East), Mumbai - 400 093
~ Phone: 022- 28209506, 28200195; 28200 196; ~ Fax: 022 - 28370193
Website: www.wrpc.gov.in E-mail: prc-wrpc@nic.in.protectionwrpc@gmail.com
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Please find enclosed herewith Agenda of 123rd Protection Committee Meeting of WRPC, to be held at
11:00 Hrs on zo" & 21 st
January, 2015 at WRPC, Mumbai.
rd
Agenda of 123 PCM is also available on WRPC website (i.e.www.wrpc.gov.in) and the same may
please be downloaded. It is kindly requested that officers participating may come along with presentations
for major occurrences/disturbances under Item No.2 in their system.
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XSuperintending Engineer (Protection)
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Mailing list
1) Chief Engineer (LD), MSETCL, Kalwa. Fax-27601769/65
2) Chief Engr. (Trans O&M), MSETCL, Bandra. Fax No. 022 - 26590808/26598587.
3) CE (W), MSEGCL, 3rd floor, Prakash gad, Mumbai.
4) S.E. (T&C), MSETCL, Aurangabad Fax-0240-2234220 /2346290
5) S.E (T&C), MSETCL, Pune. Fax-9520-2617532/2612342
6) Dy. CE (Testing), MSETCL, Koradi, Nagpur. Fax- 07109 - 262162
7) S.E.(T&C), MSETCL, Vashi Fax- 022-27656039 /27653463
8) S.E.(Testing), Bhusawal, Dist: Jalgaon Fax-02582-250379
9) S.E.(TCC), MSETCL, Karad. Fax.No. 02164 255118
10) Chief Engineer (Gen), GSECL, H.O. Baroda. Fax-0265-5512129/2344537
11) S.E. (Testing), GETCO, Baroda. Fax-0265-2351218
12) Chief Engineer (LD), MPPTCL, Jabalpur, Fax - 0761- 2664343 / 2970119.
13) E.D. (T&C), MPPTCL, Jabalpur. Fax-0761-2702710
14) ED (Engg.) MPPGCL, Jabalpur Fax- 0761-2660063
15) Chief Engineer (LD), CSPTCL, Raipur. Fax-0771 - 2574174
16) C.E. (T&C), CSPTCL, Raipur.Fax-0771-2574749
17) EE (T), CSPGCL- Fax.No. 07789-226227
18) S.E. (T&C), CSPTCL, Bhilai. Fax.No. 0788 - 2281561
19) S.E. (T&C), CSPTCL, Raipur. Fax No.0771 – 2574749 / 2574458.
20) EE, Division VIII (MRT),Elect. Dept; Goa Fax 0832-2735124.
21) Supdt.Engr., Electricity Dept., DNH, Silvasa. Fax : 0260-2642338
22) Executive Engr., Electricity Dept. DD. Fax: 0260-2250889
23) D.G.M. (O.S. ),N.T.P.C., Mumbai, Fax- 28216692
24) DGM, NTPC WR – II, Raipur, Fax: 0771 - 2544550
25) D.G.M. (EM), KSTPS, NTPC, Korba Fax 07759-233088 (Tele fax: 232440) /237462
26) DGM (EMD), VSTPS, NTPC, Vindhyachal Fax-07805-247713 /247711
27) DGM (EM-I), NTPC, SIPAT Fax-07752-246506 (Tele fax: 246691)
28) AGM (O&M), KGPP, Adityanagar, Surat Fax 0261-2861428/2861433
29) Sr. Supdt. (EM), Gandhar, NTPC Fax-02642-87402 / 87450
30) DGM (O.S.), WRLDC, Mumbai Fax-28235434
31) DGM, WRTS-I, PGCIL, Nagpur, Fax- 0712- 2631051 / 641366
32) AGM, WRTS-II, PGCIL, Baroda Fax-0265-2480952 (Tele fax: 2487542)
33) AGM, O&M, WRTS – III, PGCIL, Raipur. Fax: 0771 - 2970450
34) SME (E), TAPS-3&4,Tarapur Fax 02525-282001/282073
35) Maintenance Superintendant, TAPS –1 & 2, Tarapur.Fax- 02525-282121
36) SME(E), NPCIL , Kakrapara Fax 02626-234266
37) GM (Maint.). TORRENT Power., Ahmedabad.Fax-079-27506679
38) AGM (QAIT), TPC, Trombay. Fax –022-66687088
39) Asst. VP, Dahanu TPS Fax- 952528-222576 / 222039
40) GM (O & M), Reliance Infrastructure Limited, Mumbai Fax-30094488
41) GM (Electrical), JPL, Raigarh, Fax. No. 7767-281995, 281993.
42) AGM (OS), NSPCL, New Delhi . Fax.No.011 26717381/26717363/26717366
43) Vice President, APL, Ahmedabad 079-25557176
44) GM, RGPPL, Anjanwel, Guhagar, Ratnagiri, Fax.No. 02359 241071
45) GM, JSW Energy Ltd., Jindal Mansion, Mumbai- Fax.No.022 23526400
46) GM, CGPL, Mundra Fax.No. 02838 661188
47) VP, EPTCL, Hazira, Surat, Gujarat Fax: 0261 - 6682747
48) Director (G M Division), CEA, New Delhi. Fax.No.011-26109750
49) CE, SLDC, GETCO, Gotri, Vadodara
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2.1 Occurrence on 01.09.2014 at 400 kV Jetpur S/s, Gujarat: GETCO intimated that on 01.09.2014
at 13:24 Hrs, severe hot glows observed on fixed contact of ‘B’ ph pantograph isolator of CGPL Mundra
– Jetpur # 2 (connected to bus – I) at 400 kV Jetpur S/s. Process of line isolation was initiated but at the
same time, all elements connected to bus – I tripped on LBB operation.
Prior to occurrence, the busbar arrangement at Jetpur S/s was as follows:
400 KV Bus - 1: 400 kV Jetpur – Mundra (CGPL) # 2, 400/220 kV, 315 MVA ICT No. 3 & 400/220
kV, 500 MVA ICT No. 4
400 KV Bus - 2: 400 kV Jetpur – Mundra (CGPL) # 1 (HV off), 400 KV Jetpur - Amreli # 2
(HV off), 400/220 kV, 315 MVA ICT No. 1 & 2
400 KV TBC: 400 kV Jetpur - Amreli line No. 1
During the incident, there was no loss of load/generation. All elements were restored by 08:19 Hrs of
02.09.2014. Details are given at annexure – 2.1.
Committee may like to discuss in detail.
2.2 Occurrence on 04.09.2014 at 220/66 kV Magarwada S/s, DD: WRLDC intimated that on
04.09.2014 at 12:44 Hrs, 220 kV Vapi (PG) – Magarwada # 1 tripped on R ph E/F at 220/66 kV
Magarwada S/s. 220 kV Vapi – Magarwada # 2 was already tripped on Y – B ph to E/F at 10:03 Hrs.
This has resulted in loss of supply to DD. The total loss of load during this incident was 174 MWs. Both
lines restored by 13:26 Hrs. Details of the event enclosed at annexure – 2.2.
Committee may like to discuss in detail.
2.3 Occurrence on 04.09.2014 at 400 kV Paras S/s: MSETCL intimated that station transformer – I
(ST - I) was under outage from 02.09.2014 for maintenance work. On 04.09.2014 at 18:52 Hrs, while
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charging of above transformer through bus – I, O/C, LBB & E/F of the ST - I were operated, thus
resulted in tripping of all elements connected to this bus. The total loss of generation during this event
was 167 MWs. All elements, except station TF – I, were restored by by 20:00 Hrs and station
transformer was restored by 19:45 Hrs of 06.09.2014. Details of the event enclosed at annexure – 2.3.
Further it was intimated that, thorough testing of CB was carried out and results found to be
correct and no conclusion was drawn from DR. On inspection it was found that trip relay 86 ST and its
CMR 86 STX were malfunctioned. These relays have been replaced.
Committee may like to discuss in detail.
2.4 Occurrence on 05 & 06.09.2014 at 400 kV APL, Mundra S/s: WRLDC intimated that SSR was
observed on 05.09.2014 & 06.09.2014 at 400 kV APL, Mundra. On 05.09.2014 SSR was observed for 3
times (10:53 Hrs – 13:00 Hrs; 13:30 Hrs – 16:00 Hrs & 19:20 Hrs – 19:42 Hrs) & on 06.09.2014 for 2
times (09:20 Hrs – 09:40 Hrs & 15:45 Hrs – 16:07 Hrs).
On 05.09.2014, at 10:48 Hrs, 400 kV APL – Sami # 1 was hand tripped to regulate/control the
voltage. This was followed by activation of SSR damping controller (tuned for 660 MWs units) & SSR
oscillations were observed at APL, Mundra, which resulted in fluctuation in voltage (3 – 4 kV variation
in 400 kV & 220 kV) & currents. It was also intimated that SSR was diminished on 05.09.2014 at 19:42
Hrs & on 06.09.2014 at 09:40 Hrs with switching off of filter 10CF32 and on 06.09.2014 at 15:55 Hrs
with ramping of HVDC power (decrease in firing angle - Alpha). So, the SSR might be associated with
synchronous torsional interaction of HVDC. Details of the event enclosed at annexure – 2.4.
The studies may be performed, to review and revise the settings of the SSR damping
controller with inclusion of 330 MW units also. Previously, SSR was observed at APL, Mundra on
30.05.2014, the same was discussed in 122nd PCM at item no. 2.35.
Committee may like to discuss in detail.
2.5.a Occurrence on 09.09.2014 at 400 kV SSP S/s: WRLDC intimated that on 09.09.2014 at 400 kV
SSP S/s, at 17:25:18 Hrs B Ph to E/F occurred on 400 kV SSP – Rajgarh # I (connected to bus - I). The
line got reclosed after 1 second in zone – I carrier aided protection. After 2 seconds, at 17:25:20 Hrs,
400/220 kV ICT opened and its R & B phases got opened while Y ph got stuck at 400 kV side. This led
to stuck breaker condition, led to LBB operation, thus all elements connected to 400 kV bus – I. During
this event, loss of generation was 590 MWs. All elements were restored by 16:25 Hrs. The details of the
event enclosed at annexure – 2.5.a.
Committee may like to discuss this in detail.
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2.5.b Occurrence on 10.09.2014 at 400 kV Indore S/s: MPPTCL intimated that on 10.09.2014 at
00:20 Hrs, at 400 kV Indore S/s, earth wire of 220 kV Indore – Indore South Zone – I (connected to 220
kV bus - I) snapped and resulted in ‘B’- ph E/F. The line tripped from 220 kV S/s South Zone end only,
at Indore end CB got stuck due to burning of breaker coil of Y ph pole of CB (resulted in flashover &
arcing). Hence, LBB protection of 220 kV Indore – South Zone Ckt – I operated and resulting in
trippings of all elements connected to bus – I. Along with these, 220 kV Indore – Indore SZ # II
(connected to bus – II) tripped form Indore end & 132 kV Rau Khedi – MSP line tripped from MSP end
on B ph O/C. Further, MPPTCL intimated that, 220 kV Indore – Indore SZ – II could have tripped as it
was under the flash over zone of 220 kV Indore – Indore SZ – I. During this occurrence, the total loss of
load was 187.4 MWs for 30 minutes and power supply was interrupted to nearby areas. All elements
were restored by 01:08 Hrs. The details are enclosed at annexure – 2.5.b.
Committee may like to discuss in detail.
2.6 Occurrence on 15.09.2014 at 220 kV Vapi S/s: GETCO intimated that 15.09.2014 at 12:44 Hrs, at
220 kV Vapi S/s, 11 kV bus fault occurred, simultaneously all elements connected to 220 kV bus – I
were tripped. During this, total loss of load was 12 MWs. All elements were restored by 14:05 Hrs. The
details of the event enclosed at annexure – 2.6.
It further intimated that as the activation of busbar protection scheme of 220 kV bus – I in
reflection of 11 KV bus fault was not desirable, thorough checking of protection scheme was carried out
on 17.09.14. It was found that the CT core of TF – II, utilized for busbar protection scheme was
damaged and same was replaced.
Committee may like to discuss in detail.
2.7 Occurrence on 16.09.2014 at 220 kV Uran S/s: WRLDC intimated that on 16.09.2014 at 05:37
Hrs, all running units of Uran (unit 5, 6, 7, A0 & B0) tripped due to problem in gas skidding system
(This system is used to filter out liquid & solid contaminants from gas and adjusts temperature of the gas
to be injected into combustion chamber). The total loss of generation was approximately 273 MWs. All
units were restored by 20:24 Hrs. The details of the event enclosed at annexure – 2.7.
Committee may like to discuss in detail.
2.8 Occurrence on 17.09.2014 at 400 kV JP Nigrie S/s: WRLDC intimated that on 17.09.2014 at
19:47 Hrs, at 400 kV JP Nigrie S/s, 400 kV Satna – JP Nigrie - # II tripped on B ph E/F (Gen Capacity
is 2 X 660 MWs, but only one unit was declared for COD). Simultaneously unit at JP Nigrie got tripped
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due to relay coordination problem. Thus bus I & II got isolated and bus – I lost supply. The total loss of
generation during this event was 335 MWs. 400 kV JP Nigrie – Satna – II & JP Nigrie unit – I were
restored by 00:45 Hrs & 06:18 Hrs of 18.09.2014 respectively. The details of the event enclosed at
annexure – 2.8.
Committee may like to discuss in detail.
2.9 Occurrence on 19.09.2014 at 400 kV Korba (W) S/s: CSPTCL intimated that on 19/09/2014
weather was cloudy, thundering and frequent lightening was taking place in nearby vicinity of Korba
(W) S/s. Bus – I was under maintenance and was charged at 12:44 Hrs, while transferring feeders from
bus – II to bus I, at 12:55:49 Hrs, one tension string of ‘B’ phase of 400 kV bus – I between bay – II &
III was found shattered and fallen down, other parallel tension string of same location was also damaged
badly and hanging. Thus bus fault occurred on bus – I and as busbar protection at Korba (W) was out
since 2007, all lines tripped form remote end and generators & ICTs tripped on backup protection. Thus
units 3, 4 & 5 were tripped and resulted in total generation loss of 703 MWs. Hence 400 kV bus – I & II
of Korba (W) become dead. All elements were restored by 19:42 Hrs except 400 kV Korba – Korba (W)
line & Korba (W) unit – 5. 400 Korba – Korba (W) line was restored on 20.09.2014. During this event,
turbine of Korba (W) – unit – 5 got damaged, hence is under outage. 400 kV bus – I was charged on
29.09.2014 after rectifying the damaged portion. The details of the event enclosed at annexure – 2.9.
Committee may like to discuss in detail.
2.10 Occurrence on 21.09.2014 at 220 kV Wani S/s: MSETCL intimated that on 21.09.2014 at 10:12
Hrs, B-phase PT (SCT make) of 220 kV bus section – II got burst due to insulation failure, resulted in
bus fault and led to busbar operation and elements connected to bus section – II along with bus
sectionalizer got tripped.
Elements on bus section – I: 220 kV Wani – Chandrapur, 220/33 kV 25 MVA ICT – I
Elements on bus section – II: 220 kV Wani – Warora, 220/33 kV 50 MVA ICT – II
During this event 9.3 MWs load was affected on 33 kV feeders for 29 mins. 220 kV Wani –
Warora restored at 10:36 Hrs and 50 MVA ICT – II restored at 10:41 Hrs. The failed PT replaced with
new PT (SCT make) on 24.09.2014. The details of the event enclosed at annexure – 2.10.
Committee may like to discuss this in detail.
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fluctuations were dominant around Bhadravati PMU. Initially it was suspected that this might be related
to HVDC converter terminal of Bhadravati or Chandrapur, hence, the power flow through HVDC
Bhadravati reduced by 300 MWs. Later it was found that at 13:47 Hrs Mauda unit – II was hand tripped
on ETW pump failure. It was followed by decrease in reactive power absorption (30 MVAr to 8 MVAr)
& increase in active power (350 MWs to 450 MWs) of unit – I. After 14:07 Hrs, it was observed that
reactive power absorption was increased suddenly (from 8 MVAr to 55 MVAr). Details are enclosed at
annexure – 2.11.
Committee may like to discuss this in detail.
2.12 Occurrence on 23.09.2014 at 220 kV Chinchdwar S/s: MPPTCL intimated that on 23.09.2014 at
13:55 Hrs at 220 kV Chinchdwara S/s, Y ph PT of main bus – I got burst, led to busbar operation
resulted in tripping of all elements (220 kV Chhindwara-Pandhurna Ckt, 220 kV Chhindwara-Betul Ckt,
220 kV Chhindwara-Seoni(PGCIL) Ckt- I&II and 220/132 kV, 160 MVA X’mer at 220 kV S/s
Chhindwara tripped) connected to bus – I. During this occurrence there was no loss of load or
generation. All elements were restored by 15:16 Hrs. Details are enclosed at annexure – 2.12.
Committee may like to discuss this in detail.
2.13 Occurrence on 26.09.2014 at 400 kV Waluj (Aurangabad) S/s: MSETCL intimated that on
26.09.2014 at 400 kV Waluj S/s at 07:12 Hrs, B ph CT (make – Universal Magnoflux) of 220 kV Waluj
– Bhenda ckt (connected to 220 kV main bus - I) got burst, caught fire and fell down and led to 220 kV
bus fault, resulted in tripping of all elements connected to 220 kV main bus – I at 400 kV Waluj S/s.
Due to tripping of 220 kV Waluj – Padegaon line, load trimming scheme operated at Padegaon S/s
(tripped 132 kV Padegaon – Pishor & other 33 kV feeders). MSETCL also reported that that A/R
operation at Bhenda end is unsuccessful. All elements (at Waluj & Bableswar S/s) were restored by
21:34 Hrs. Details are enclosed at annexure – 2.13.
Further it (MSETCL) intimated that the CT failure matter was taken up with manufacturer
M/s Universal Magnoflux. WRLDC intimated that due to above busbar operation, load at Bhenda was
shifted to Bableswar and resulted in over loading of ICTs led to tripping these. Further it led to over
loading of incoming feeders at Bableswar resulted in tripping of these feeders tripped from remote end
on O/C. Thus 220 kV bus at Bableswar S/s became dead. This led to 520 MWs load loss at
Ahmednagar. Thus during this occurrence total loss of load was 790 MWs.
Committee may like to discuss this in detail.
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2.13.b Occurrence on 27.09.2014 at 220 kV Khaparkheda S/s: MSETCL – Nagpur intimated that on
27.09.2014 due to the tripping of Paras unit- 3 (250 MVA) at 13:26 hrs, at 220 kV Khaparkheda S/s at
15:26 hrs the VKM system got overloaded resulting in tripping of 220 KV Khaperkheda to 400 KV
Khaperkheda circuit I & II and overloading of ICTs at old Koradi sub-station. The details are enclosed
at annexure – 2.13.b.
2.14 Occurrence on 30.09.2014 at 220 kV Pitampur S/s: MPPTCL intimated that on 30.09.2014 at
17:33 Hrs B ph CT of 220/132 kV 160 MVA transformer (connected to 220 kV main bus - II) got burst
at 220 kV Pitampura S/s, created bus fault and led to operation of busbar protection of 220 kV main bus
- II. Thus all elements connected to this bus got tripped along with these 220 kV interconnector – II
(connected to 220 kV main bus – I) also tripped from 400 kV Pitampura S/s on B ph in zone – II
indication due to jerk. Thus load of ICT – II shifted to ICT – I and led to operation of load trimming
scheme. During this occurrence power supply was interrupted to 132 kV Jamli, 132 kV Betma & 132
kV Badgi S/ss. The total loss of load during this event was 68 MWhrs. All elements (except ICT - II)
were restored by 18:52 Hrs and the ICT – II was restored on 10.09.2014. The details are enclosed at
annexure – 2.14.
Committee may like to discuss this in detail.
2.15 Occurrence on 01.10.2014 at 400/220 kV Padghe S/s: MSETCL intimated that on 01.10.2014, at
10:22 Hrs, 220 kV Y ph CT (SCT make) of 3 X 200 MVA ICT – IV (connected to 220 kV main bus - I)
got burst and caught fire at 400 kV Padghe S/s. It also damaged CTs of R & B phases of ICT – IV and
the ICT tripped on differential protection. Due to fumes & flames of burnt CT, R ph E/F created on 220
kV Padghe – Jindal line (on 220 kV main bus – I and is adjacent to burnt CT), the A/R operated at both
ends but tripped immediately at Jindal end on SOTF, thus line is connected from Padghe end. All
elements connected to bus – I tripped on backup protection. Subsequently 315 MVA, 400/220 kV ICT 1
&2 and 220 kV Padghe – Temghar also tripped, which were on 220 kV main bus – II at 400 kV Padghe
S/s. Hence load of Padghe shifted to 315 MVA, 400/220 kV ICT – I & II, inspite of operation load
trimming scheme these ICTs tripped on backup O/C. During this the voltage at 220 kV Padghe dropped
to 185 kV and remained almost for 30 minutes i.e. till the restoration of 400 kV ICTs. All elements
were restored by 20:06 Hrs. The details are enclosed at annexure – 2.15.
Further WRLDC intimated that during this event, TAPS unit – III tripped as its auxiliaries
tripped on low voltage. The total loss of load during this incidence was 1500 MWs and loss of
generation was 540 MWs.
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MSETCL may give the reason for non-operation of busbar protection of 220 kV main bus – I.
Committee may like to discuss this in detail.
2.16 Occurrence on 01.10.2014 at 400 kV JP Nigrie S/s: WRLDC intimated that on 01.10.2014 at
10:34 Hrs 10:34 Hrs, 400 kV JP Nigrie – satna – II tripped on R Ph E/F, at the same time 400/220 kV
ICT – I at 400 kV Satna S/s got tripped on O/C protection. During this event there was no loss of load or
generation. The tripped line restored at 04:20 Hrs on 02.10.2014. The details of event enclosed at
annexure – 2.16.
The tripping of 400/220 kV ICT – I at Satna S/s on O/C is not clear, PGCIL may give the
reason for the same.
Committee may like to discuss this in detail.
2.17 Occurrence on 03.10.2014 at 220 kV Pophali (New Koyna) S/s: WRLDC intimated that on
03.10.2014 220 kV Pophali – Kandalgaon line was taken on TBC to carry out conductor replacement of
bus isolator. At 19:10 Hrs, R ph to E/F occurred on this line, A/R is operated at Kandalgaon end and
distance protection operated at Pophali end, but TBC CB didn’t trip. It led to operation of LBB at 220
kV Pophali S/s, thus all elements connected to this bus were tripped. The load loss of load during this
event was 20 MWs.
It was also intimated that the trip wire of TBC CB was loose and it was rectified and all
elements were restored by 00:37 Hrs of 04.10.2014. The details are enclosed at annexure – 2.17.
Committee may like to discuss this in detail.
2.18 Occurrence on 06.10.2014 at 220 kV Badod S/s: MPPTCL intimated that on 06.10.2014 at 19:09
Hrs, Y ph of 220 kV Badod – Kota (connected to 200 kV main bus - II) got burst at 220 kV Badod S/s
and created bus fault, resulted in busbar operation thus all elements connected to 220 kV main bus – II.
During this event, there was no loss of load or generation. The PT was replaced and all elements were
restored by 18:42 Hrs of 08.10.2014. The details of the occurrence are enclosed at annexure – 2.18.
Committee may like to discuss this in detail.
2.19 Occurrence on 09.10.2014 at 400 kV R. S. New Koyna S/s: MSETCL intimated that on
09.10.2014, online shifting of New Koyna – Karad – II from bus – II to bus – I was planned at 400 kV R
S New Koyna S/s. While shifting this, NTC (Neutral Trip and Close) was changed to T (trip) position,
immediately all elements connected to bus – I along with bus coupler were tripped.
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Further it was intimated that conditions of occurrence were simulate and found that the
positive was getting extended to busbar trip. The suspected 96 TBC Y ph relay was replaced and all
elements were restored by 13:05 Hrs. The details of the occurrence enclosed at annexure – 2.19.
Committee may like to discuss this in detail.
2.19.b Occurrence on 19.10.2014 at 400 kV Khaparkheda S/s: MSETCL – Nagpur intimated that on
19.10.2014, at 400KV Khaperkheda S/s at 19:57 Hrs, B ph CT of 500 MVA, 400/220KV ICT-II failed,
resulting in tripping of 220KV Bus-II thus ICT-II tripped along with bus coupler. The details are
enclosed at annexure – 2.13.b.
2.20 Occurrence on 12.10.2014 at 400/220 kV Kalwa S/s: WRLDC intimated that on 12.10.2014 at
400/220 kV Kalwa S/s, at 04:56 Hrs 220 kV B ph CT (ITC make) of 3 x 167 MVA ICT - III (connected
to 220 kV main bus – II) got burst and caught fire at 400/220 kV Kalwa S/s, the differential protection
of ICT – III but simultaneously 220 kV busbar zone – II protection also operated, resulted in tripping all
elements connected to 220 kV main bus – II. Due to fumes and fire, R ph to E/F created on adjacent 220
kV Kalwa – Mulund ckt – II, the fault was cleared from Kalwa end on BB operation and on backup O/C
protection from 220 kV Mulund end. Along with these, 220 kV Kalwa – Borivali line (connected to 220
kV main bus – I) also tripped from Borivali end on distance protection for B ph E/F in Zone – I from
Borivali end. The total loss of load during the event was 160 MWs. All elements were restored by 19:44
Hrs. Details of the occurrence are enclosed at annexure – 2.20.
Committee may like to discuss this in detail.
2.22 Occurrence on 16.10.2014 at 765/400 kV Solapur (PG) S/s: WRLDC intimated that on
16.10.2014 at 13:14 Hrs, due to human error, both 765/400 kV ICTs I & II were hand tripped by
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operator instead of tripping of ICT – II. This has resulted in loss of synchronism between NEW & SR.
The system was restored by 15:44:23 Hrs. The details of the event enclosed at annexure – 2.22.
Committee may like to discuss this in detail.
2.23 Occurrence on 19.10.2014 at 220 kV SLPP S/s, GETCO: GETCO intimated that on 19.10.2014
at 21:03 Hrs,R ph EMVT of 220 kV bus ‘A’ of stage I failed, resulted in operation of bus under voltage
& busbar differential relays. As the busbar protection relay failed isolate the faulty system, all elements
connected to the bus were tripped on back up protection. The total loss of generation during this event
was 475 MWs. The details of the event enclosed at annexure – 2.23.
Committee may like to discuss this event in detail.
2.24 Occurrence on 23.10.2014 at 400 kV Uran S/s: WRLDC intimated that on 23.10.2014 at 400 kV
Uran S/s, at 08:35:40 Hrs B Ph pole of 22 kV side CB of 220/22 kV, 50 MVA ICT – II got burst &
caught fire along with flashover underneath of local control cubicle of CB at 220 kV Uran S/s. It
damaged all control cables of HV system. The bursting of CB pole created bus fault on 22 kV system
side, though it was through fault for the ICT, the fault was not sensed at 220 kV level due to damage of
control cables. But simultaneously, 220 kV Uran – Kharghar – I, 220 kV Uran Apta – I, III & IV tripped
from Uran end only due to DC grounding/leakage developed in Dc source. As the fault was not cleared,
it led to internal fault in ICT, but it was not cleared due to failure of operation of protection. This led to
high fault current on HV side of ICT, thus led to tripping of Uran – Apta – I & 220 kV Uran – Khargar –
II from remote end along with these, Uran units 6, 7, 8, A0 & B0 also tripped. Thus complete power
supply was lost to Uran S/s. During this event, loss of generation was 458 MWs & load loss was 34
MWs. All elements were restored by 25.10.2014. The details of the event enclosed at annexure – 2.24.
Committee may like to discuss this in detail.
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2.26 Occurrence on 30.10.2014 at 220 kV Mudshingi S/s: MSETCL intimated that on 30.10.2014 at
20:45 Hrs R ph CT (Areva make) of 220 kV Mudshingi – Walthar got burnt & burst at 220 kV
Mudshingi S/s, and resulted in operation of busbar protection. During this incidence, the loss of load
was 104 MWs at Kolhapur. All element were restored by 21:41 Hrs. The details of this event are
enclosed at annexure – 2.26.
Committee may like to discuss.
2.27 Occurrence on 30.10.2014 at 220 kV Rewa S/s: MPPTCL intimated that on 30.10.2014 at 17: 25
Hrs, at 220 kV Rewa S/s, suspension disc between CB of 220 kV Rewa – Sidhi line & isolator of 220
kV main bus failed, led to bus fault and resulted in busbar operation at 220 kV Rewa S/s. Thus all
feeders connected to this bus tripped. During this, the cable for supply to breaker oil of Y ph of 220 kV
Rewa – Sidhi was also got damaged. Total loss of load during this event was 141 MWHrs for 94 mins.
All elements except 220 kV Rewa – Sidhi were restored by 19:47 Hrs and 220 kV Rewa – Sidhi
restored at 09:40 Hrs on 01.11.2014. The details of the event enclosed at annexure – 2.27.
Committee may like to discuss.
2.28 Occurrence on 10.11.2014 at 220 kV Pophali S/s & 220 kV Pedambe: MSETCL intimated that
on 10.11.2014 at 15:42 Hrs at 220 kV Pedamba S/s, jumper between bus isolator & CB of 220 kV
Pedamba – Pophali # I (on bus section – I of Pedambe S/s) was snapped and fell on CB mechanic box.
As busbar protection failed to operate, thus Generator unit – 10 tripped at 220 kV Pedambe S/s, 220 kV
Pedambe – Mahad & 220 kV Pedambe – Now Koyna lines tripped from remote end on distance &
backup protection respectively.
The fault was in Zone – II at Pophali S/s, as there was problem in CB of the faulty line at
Pophali S/s, LBB of this line operated, thus all elements (Generator – I, II, III & IV) connected to this
bus were tripped along with bus sectionalizer. At the same time, heavy sparking was observed on R ph
jumper of bus isolator of 220 kV Pophali – New Koyna line at Pophali S/s. This line was immediately
hand tripped from Pophali end, meanwhile 220 Kv Pophali – Pedambe # II tripped at Pedambe end.
Thus only one evacuation line i.e. 220 kV Pophali – Nerle – Karad was available for generation (Unit –
5, 6, 7, & 8) at Pophali S/s and got over loaded. The 220 kV Nerle – Karad tripped on O/C at Nerel end.
Hence, all generators (Unit -5, 6, 7 & 8) tripped, thus 220 kV bus at Pophali S/s got dead. During this
occurrence the total loss of generation was 640 MWs. All elements were restored by 22:11 Hrs. The
details of the event are enclosed at annexure – 2.28.
Committee may like to discuss this in detail.
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2.29 Occurrence on 11.11.2014 at 220 kV OSP S/s: MPPTCL intimated that on 11.11.2014 at 20:56
Hrs all lines emanating from OSP HPS were tripped on O/V. Thus due to loss of evacuation line, all
generators tripped at 220 kV OSP HPS. All elements were restored by 23:21 Hrs. Further it intimated
that the reason for high voltage in system was due to sudden load/demand crash in western MP due to
rains. The details of the tripping enclosed at annexure – 2.29.
Committee may like to discuss this in detail.
2.30 Occurrence on 13.11.2014 at 400 kV SGTPS, Birsinghpur S/s: MPPTCL intimated that on
13.10.2014 at 400 kV SGTPS, Birsinghpur S/s, light up of unit – II (210 MWs) was in progress.
Immediately after giving close command to generator breaker (to 220 kV bus – II at 400 kV SGTPS
S/s), at 12:46:07.212 Hrs, its 220 kV R ph pole burst and created bus fault on 220 kV side. As there was
busbar protection for 220 kV was not available, all elements connected this bus tripped on back up
protection. All elements were restored by 10:35 Hrs of 15.11.2104. The details of the event enclosed at
annexure – 2.30.
It was also intimated that during the CB closing, R ph pole insulator got shattered, thus SF6
gas leaked and exposed to air, led to ionization of surrounding air and created arching earth fault, thus
trip command issued to generator breaker. This arc further ionized surrounding air and created bus side
arching earth fault.
Committee may like to discuss this in detail.
2.30.b Occurrence on 18.11.2014 at 220 kV Butibori –III S/s: MSETCL – Nagpur intimated that on
18.11.2014, at 220 kV Butibori – III at 19:37 Hrs, due to bursting of ‘B’ph CT of 220KV Butibori-III –
Butibori-I circuit, busbar protection scheme of Bus-I operated, resulted in tripping of all feeders
connected to Bus-I & Bus coupler. At the same time, ‘B’ ph wave trap of 220KV Butibori-I- Butibori-
III circuit burst, resulting in tripping & successful A/R of 220KV Butibori-I – Khaperkheda & 220KV
Butibori-I – Abhijeet circuit. The details are enclosed at annexure – 2.13.b.
2.31 Occurrence on 29.11.2014 at 220 kV South Solapur S/s: MSETCL intimated that on 29.11.2014
at 00:40 Hrs, B ph PT (Mehru make) of section – II of 132 kV bus was failed at 220 kV Soth Solapur
S/s, led to operation of 132 kV busbar protection and selective tripping elements connected to it.
Simultaneously, distance protection of 220 kV PGCIL – Solapur # II also operated at PGCIL end and
issued DT to remote end. The details of the event are enclosed at annexure – 2.31.
Committee may like to discuss this in detail.
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ITEM NO. 3: Tripping of lines / ICTs: The minor incidences of tripping of lines and ICTs during the
period 01-09-2014 to 30-11-2014 are enclosed at Annexure–3.
In the 121st & 122nd PCMs, Committee suggested that the utilities may indicate as to whether
A/R is provided on the lines and whether the A/R for transient fault was successful or the A/R locked
out for permanent faults, in their line/element trippings. Constituents are requested to provide A/R
availability/status for each line.
Committee may like to discuss.
ITEM NO. 4: Hon’ble CERCs orders on the Grid disturbance of 30.07.2012 & 30.07.2012.
4.1: Status of compliance of the Protection Audit observations (Petition No. 220/MP/2012).
4.1.1: Back ground: CERC’s vide order dated 21.02.2014 in petition No. 220/MP/2012 filed by
POWERGRID have observed that “since the protection system is a vital requirement for the safe
and secure operation of the grid, we have decided that in order to implement the
recommendations of the Protection Audit, a compliance mechanism with definite time line needs
to be put in place”.
CTU and SLDCs shall submit quarterly report to the respective RPC latest by 15th day of the first
month of next quarter and RPCs shall submit the report to the Commission latest by 15th day of the
second month of next quarter. The Member Secretaries, Regional Power Committees shall continue
monitoring the protection related issues and bring to the notice of the Commission any instance of non-
compliance of the Regulation 1.5 of the Grid Code in respect of the protection related issues considered
in the instant petition.
In view of the above directions of Hon’ble Commission, SLDCs were requested to collect and
compile the data of respective STU’s and WRLDC was requested to collect and compile the data of all
the ISGS, Goa, DD & DNH in the format given at Annexure 4.1, by WRPC vide letters dated
05.10.2013 & subsequent email dated 04.12.2013 and 26.03.2014 . The time lines for compliance of the
above directives and submission of data to WRPC is as follows.
The time lines for compliance of the above directives and submission of data to WRPC is as follows
Updated Data up to Date by which SLDC/WRLDC/ Compliance of the Protection Audit
CTU shall submit the data to deficiencies
WRPC Category-A Category-B
Up to Feb.14 30th Mar 2014
Qtr-1 (Jan 14 to Mar 14) 25th April 2014
Qtr-1 (Apr 14 to Jun 14) 15th July 2014 21st April 2014 21st August 2014
Qtr-1 (Jul 14 to Sep 14) 15th October 2014
Qtr-1 (Oct 14 to Dec 14) 15th Jan 2015
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4.1.2: Follow up: In the 121st & 122nd PCM, it was reiterated that delay in submission of the above data
may attract non-compliance of the Hon’ble Commissions order.
The status of compliance of observations of protection audit of WR utilities was
reviewed in the special meeting held on 18.12.2014 & the status is as follows. The data received
from MSETCL as on November - 2014, CSPTCL as on June - 2014, MP as on August – 2014,
GETCO as on March – 2014, NTPC as on November - 2014 and PGCIL – WR – II as on March –
2014. The data is received from PGCIL – WR – I. The data pertaining to ISGS, ISTS, Goa, DD &
DNH is not received by WRLDC. The updated list of deficiencies in respect of constituents
(MSETCL, CSPTCL, GETCO, MPPTCL & PGCIL – WR - II) is enclosed at annexure 4.1.2.
In the special meeting held on 18.12.2014 the group observed that few deficiencies mentioned in
the list are not deficiencies in respect to protection relaying system but are of system
improvement. Hence, related observations were requested to update the deficiencies into category
A, Category B & system improvement related observations be shown seperately. Constituents
agreed for the same.
Committee may like to discuss
4.2: Grid Disturbance on 30.07.2012 & 31.07.2012 (Petition No. 167/Suo-Motu/2012).
4.2.1: Back ground: Hon’ble CERC’s vide order dated 22.02.2014 in the matter of grid disturbance that
took place on 30.07.2012 & 31.07.2012 in petition No. 167/Suo-Motu/2012, have made certain
observations and issued directions.
All the RPCs have been directed to maintain the relay settings data of all the ISTS lines and
lines emanating from interface S/Ss of Utilities to ISTS and therefore utilities are requested to submit
the data of their system. In the 121st PCM, constituents were requested to submit the relay setting data to
WRPC/WRLDC.
4.2.2: The status was discussed in the special meeting held on 18.12.2014 and the group suggested
that data is received from MPPTCL only. Other constituents may also submit the data at the
earliest. The sample format for data submission is enclosed at Annexure - 4.2. WRLDC/SLDCs
may co-ordinate for the data.
Committee may like to note/discuss.
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The updated status of implementation of various recommendations of the grid disturbance enquiry
committee as on 1st & 15th of each month is required to be forwarded to CEA by RPCs by 3rd & 17th of
every month regularly.
The nodal officers identified & responsible for submission of data are as follows;
1. WRLDC: GM WRLDC
2. PGCIL-I: DGM(OS)
3. PGCIL-II: DGM(OS)
4. NTPC WR-II: AGM(OS) & DGM(OS)
5. GETCO STU: SE (Testing).
6. GETCO SLDC: CE SLDC.
7. MSETCL STU: SE, MSETCL
8. MSETCL SLDC: CE, SLDC
9. MPPTCL STU: CE, (T&C)
10. MPPTCL SLDC: CE, SLDC
11. CSPTCL STU: SE(T&C)
12. CSPTCL SLDC: CE, SLDC.
In the 120th PCM, it was decided that utilities would submit data to nodal agency/officer and
nodal agency, after compiling the data may submit it to the WRPC for timely submission of the same to
CEA/MoP. In 121st & 122nd PCM, nodal officers responsible for compilation of the data were requested
to forward the data at the earliest for onward submission of the same to CEA/MoP. Any change in
nodal officer may be intimated to WRPC.
Constituents (except MP) are requested to submit the data regularly.
In the special meeting held on 18.12.2014, it was decided that the status shall be
submitted separately for protection audit carried out during the financial year (i.e. FY 2012-13,
2013-14 and quarterly for April 14 on wards) in the formats enclosed. And it was also decided that
a detailed status of all 132kV, 220kV, 400kV and 765kV Substations in the enclosed format
(Annexure 5.1.2) would be submitted within 10 days of issue of the MoM by all the utilities, as the
same was not available with WRPC. It was also agreed that SLDC and WRLDC would coordinate
to get the details of the statistics for the formats. The information in Annexure – 5.1.2 would
enable to identify the remaining S/s of WR where Protection Audit is required to be carried out
and the same can be communicated to grid study committee as desired in the meeting held on
25.07.2014 at CEA, New Delhi.
Constituents are requested to submit the same.
Committee may like to discuss this.
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test signals were received at KSTPS, VSTPS and CGPL and report from NLDC/NRLDC is yet to be
received.
PGCIL/WRLDC may update the status.
Committee may like to discuss this.
8.1.2) SPS at 400kV Vapi ICT overloading: The SPS was discussed in the special meeting held on
03.09.2013 at TAPS 3 & 4 and further finalized in the meeting held on11.04.14 at GETCO SLDC with
DD & DNH representative regarding SPS to restrict loading on 3 X 315 MVA 400/220 KV ICTs
at Vapi (PG). The SPS was discussed in the OCCM and it was felt that due to commissioning of 400 kV
Kala S/s, the ICT overloading at Vapi is not so critical.
DNH vide letter No-11(739)/ELE/2013/3382 dated 30.09.2014 have requested that the
conditions earlier envisaged (ICT overloading at Vapi) for SPS may be modified such that load
shedding shall take place in DD & DNH system by sensing the overloading/tripping of 220kV Vapi -
Kharadpada D/C lines. The estimated cost has been deposited to GETCO by DD & DNH.
Status: In 122nd PCM it was decided that GETCO, DD, & DNH to formulate suitable preliminary
scheme for the 220 kV Vapi – Kharadpada D/C line instead of ICT O/L and inform the same to
WRPC & WRLDC.
GETCO, DD & DNH may update the status of the same.
Committee may like to discuss.
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Stage-V 47.5Hz Island freq (0.8 sec time delay) Station load transfer to UT & TG CB trip for putting
the island unit under house load.
Status: KAPS representative informed that main under frequency relay (MICOM-P-941 numerical
relay) would be purchased by KAPS for Vapi Sub-station, since the existing FCX relay is defective.
GETCO agreed for procurement of other auxiliary relays and wiring of the same. GETCO representative
stated that they have planned for PLC based islanding scheme and in near future the same would be
incorporated in the Islanding scheme.
GETCO vide letter no. CE(TR)/ACE(Testing)/OCC/45/ dated /10/2014, has intimated that
the UFR is not received at 220 kV Vapi S/s. In 122nd PCM, committee requested KAPS to expedite this.
GETCO & KAPS may update the status of the same.
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a) TAPS 3 & 4 one unit to island with Boisar load and other unit to island with house load.
b) WRLDC would prepare the details of the islanding scheme in consultation with GETCO, MSETCL
& TAPS.
c) The details of the settings would be worked out by WRLDC in consultation with GETCO, MSETCL
& TAPS.
Status: In 122nd PCM, WRLDC representative stated that they would shortly convene a meeting
as suggested above.
WRLDC and TAPS 3&4 may update the status of the same.
Committee may discuss this.
8.3.4) Sugen Islanding: The formulation of islanding scheme for Sugen TPP was discussed in the
special meeting held on 03.09.2013 at TAPS 3 & 4.
The group suggested following:
a) Isolation of feed from 220 kV Kim – Sugen may be opened at higher frequency 48.2 Hz as a
preparation to islanding.
b) PLC based load trimming to be implemented to match generation at Sugen, exact settings can be
decided later.
Status: GETCO vide letter no. SLDC/CE/MIS/WRPC/Sugen Islanding scheme/3437 03.12.2014
intimated that the above scheme has been finalized. The same is enclosed at annexure – 8.3.4
Committee may like to discuss.
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All the constituents were requested to give the list of the feeders with UFRs in a soft copy
(excel sheet) within 15 days along with other details like peak load (MWs), average load (MWs), kV,
substation etc., It was also requested utilities to furnish the details of df/dt relays to WRPC in soft copy.
MSETCL, GETCO, MP & Chhattisgarh have submitted the data for UFR relays. UFR data from DD,
DNH & Goa is still not received. None of the utilities have submitted data for df/dt relays.
In 122nd PCM, representative of DNH intimated that the AUFLS will be implemented by
Dec, 2014. DD & Goa should implement the AUFLS targets at the earliest and the details of UFR
feeders, as above shall be forwarded by constituents to WRPC/WRLDC for compilation and
ready reference.
The above data may be submitted/updated at the earliest.
Committee may like to discuss.
9.2: Status of Bus Coupler and Bus Bar protections at S/s
Back Ground: In the 118th PCM, Chairman TCC stated that the Bus Bar protection schemes should be
provided by the respective utility at the earliest, without expecting funding under R&U from MoP, GoI.
In the 121st PCM it was informed that BB protection at 7 Nos of 220kV S/Ss (Single Bus S/Ss) in
GETCO system, 3 Nos of 220kV S/Ss in MSPGCL system, 7 Nos of 220kV S/Ss in MPPTCL system
& 5 Nos of 220kV S/Ss in CSPTCL system was pending.
Constituents are requested to update the status of following substations.
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1) Non Availability of Bus Bar protection at 220/132 kV Bhatapara S/s. CSPTCL may give the present.
2) Status of Bus Bar protection Scheme at 220/66 kV Magarwada S/s. DD may give the present status.
3) Bus Bar protection at 400/220 kV Korba West S/s. CSPGCL may appraise the status of LBB/Bus
Bar protection at 400/220 kV Korba West, 200/132 kV Korba East and 220 kV Korba East Extension.
Committee may like to discuss/note.
9.3: Time synchronization, non-working of DR & Main-2 of Ranchodpura line-2 at Dehgam S/s:
Back Ground: PGCIL vide letter WRTS II/O&M/273/AV/1211 dated 30.03.2013 &
WRTS/DEH/SS/385/113 dtd. 28.01.2012, have intimated that the pending protection issues related with
GETCO bays at Dehgam S/S have not been attended so far and requested GETCO for configuration of
DR for Main-1/Main-2 protection along with wiring of digital inputs & GPS time synchronization.
GETCO vide letter no. CE(TR)/ACE(testing)/OCC/45/ dated .10.2014 intimated that
disturbance recorder data is available in the numerical relay i.e. ABB makes REL 670. For time
synchronization of the same relay with GPS, GETCO has done wiring and tried to synchronize the relay
using PPM output but the output port (PPM) of GPS unit is not working and spare ports including like
IRIG-B (TTL) are not available in the GPS unit. The issue will resolved after attending port problem of
GPS unit.
GETCO may update the status.
Committee may like to note/discuss.
9.4: Auto reclosure facility at 220kV Kota and Modak ends of the 220kV Badod-Kota & Badod-
Modak lines:
MPPTCL vide their letter No.07-05/RPC-17/3495 dated 14.10.2014 have informed that The PLC
cabinets along with Protection Couplers have been checked commissioned and ready for use at 220kV
Badod S/S (MP) end. However the scheme could not be put to use due to non-availability of carrier
equipments with Protection Couplers for these inter-regional lines at 220kV Kota (Rajasthan) & 220kV
Modak S/S(Rajasthan). WRLDC have made several correspondences with MPPTCL regarding frequent
tripping of these lines on single-phase to earth fault and suggested to provide A/R.
MPPTCL representative informed that panels have been installed at NR end. Testing
would be carried out by 2nd week of Nov, 2014 & would be taken into service by the end of Nov,
2014. He also requested to take up the matter with NRLDC/NLDC, for installation of PC at Kota
end.
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Item No. 11: Report of the Task Force on Power System Analysis Under Contingencies: As a
follow up of one of the recommendations of Enquiry Committee headed by Chairman, CEA on grid
disturbances that took place in Indian grid on 30th and 31st July 2012, Ministry of Power constituted a
‘Task Force on Power System Analysis under Contingencies’ in December 2012. The Terms of
reference of Task Force broadly cover analysis of the network behavior under normal conditions and
contingencies, review of the philosophy of operation of protection relays, review of islanding schemes
and technological options to improve the performance of the grid.
The matter was in brief discussed in 122nd PCM and subsequently discussed elaborately in a
special meeting held on 18.12.2014, the MoM of the same is enclosed at annexure – 11.
The brief of suggestions given by the group is as follows.
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Suggestions: In built DEF protection of the DPS can be set for clearing the high resistance faults,
however this requires that the Z-3 time setting to be set between 1.0 - 1.5 sec. PGCIL representative
stated that the in built DEF can also clear highly resistive phase to Phase faults, since it measures both
Zero & negative sequence. It was suggested that Impedance relays on ICT can address this issue in a
more appropriate manner.
b) ZONE-1 POWER SWING BLOCKING: MSETCL representative stated that they are blocking all
the three Zones for 2 secs and the DPS is unblocked after 2 secs, if power swing is detected. Therefore if
the swing exists for more than 2 secs, the relay is allowed to trip. SE (P), WRPC pointed out that the
power swing entering in Z-1 of DPS is a serious system condition and the system would definitely fall
out of synchronism under such condition. Therefore tripping in Z-1 on power swing should be
immediate.
It was pointed out that if immediate tripping is allowed under power swing in Z-1, the system
is allowed to separate nearly at 180 degrees apart. This would endanger the breakers opening under such
conditions, since the breakers may not be designed for opening a system which is out of step. Therefore
it would be appropriate to allow a time delay since it would at least ensure that either the swing is
recoverable or the delay would avert opening the breaker when the swing is well past 180 degrees.
c) Protection Audit:
Suggestions: The Task Force on Power System Analysis under Contingencies (TFPSAC) suggested
relay setting guidelines, proposer & validator system to ensure settings are implemented correctly and
protection audits to be carried out under the guidelines suggested by the committee. The group discussed
the issues and suggested following to be put to the PCM.
i) First party audit: Every S/s of 100 kV & above shall audit the settings in line with
recommendations of the above task force by the I/c of concerned S/s. Any issues pertaining to settings
shall be discussed in the utilities internal PCM or control relay management group of utility and sorted
out. Unsorted issues can be taken up in WRPC PCM if any. The frequency of audit of first party shall be
yearly once. Also any change in settings, this procedure of audit shall be followed.
ii) Third party audit: Considering expertise available in all utilities, it was decided to form a
permanent panel of testing experts of all utilities of WR. Any utility seeking third party audit shall form
team of 3 members for audit, with two members (not belonging to to utility but from above panel).
Utility is also free to choose full third party from other agencies like CPRI. Guidelines for frequency of
3rd party audit needs to be decided by PCM.
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(i) Different Z-3 time settings adopted by PGCIL & MPPTCL: MPPTCL intimated that zone – 3
time settings adopted by MPPTCL & PGCIL are different. To minimize the fault clearing time in 3rd
Zone, which is rare, the time setting adopted in MP is 700 ms and the backup O/C, E/F setting kept
beyond 700 ms - 1000 ms for other end bus fault where bus protection is not provided whereas settings
adopted by PGCIL are not consistent with that of MPPTCL. Fault clearing time for both the ends should
be same for reliable system operation.
Committee may like to discuss.
(ii) Alternative scheme to put Auto Reclosure (A/R) in service on the EHV lines connecting to
Generating Stations - A/R on EHV lines connecting to Generating Stations kept out of service, to
avoid charging of faulty lines from Generating Stations. Many times tripping of these loaded lines on
transient faults create emergencies regarding power evacuation, power swings and system stability. That
further resulted in to backing down of generation or other operations to save the system. But all these
exercise may take considerable time.
In general, most of the transient faults occurred are of single phase to ground in nature and
A/R of the line is the best option to maintain the reliability and stability of the system. But a possibility
of auto reclose attempt on a faulty line and its anticipated impacts always discourage generating stations
to put A/R in service, as they always prefer to synchronize a healthy and charged line.
Therefore from generating station’s point of view, an auto reclose scheme can be developed to reclose
the line from generating station with some time lag (i.e. about 400 msec) after successful reclosing of
line from the remote end and also on confirmation of healthy voltages on line CVT at generating station
end. Therefore problems related to switching on faulty line from generating station can be overcome and
system availability and stability could be maintained in better way.
The logic for this alternative scheme to put A/R in service on the EHV lines at Generating Stations
may be developed as following;
1 Keep dead time setting of A/R 900 ms at remote end from generating station.
2 Keep dead time setting of A/R 1300 ms at generating station and make AND logic of reclose
command with the line CVT voltages.
The committee may like to discuss this.
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Annexure - 2.1
Sub: Report on grid incident occurred in Gujarat system on 01.09.14 at 13:24 Hrs.
On 01/09/14 at 13:24 Hrs, grid incident occurred in Gujarat Power System. There was no load or
generation loss.
400 KV Bus - 1: 400 KV Jetpur - CGPL line No. 2, 400/220 KV, 315 MVA ICT No. 3, 400/220
KV, 500 MVA ICT No. 4
400 KV Bus - 2: 400 KV Jetpur - CGPL line No. 1 (HV off), 400 KV Jetpur - Amreli line No. 2
(HV off), 400/220 KV, 315 MVA ICT No. 1 & 2
There was severe hot glow on fixed contact of B Ph, Bus – I Pantograph isolator of 400 KV
CGPL Mundra - Jetpur line No. 2. The process of line isolation was initiated. At the same
time, all elements / lines connected to 400 KV Bus-1 tripped on LBB protection. 400 KV Bus –
2 remained under charged condition through ICT on step up mode.
Immediately, 400 KV Amreli - Jetpur line No. 2 was taken in service on 400 KV Bus II at 13:45
Hrs and 400 KV Jetpur - CGPL line No. 1 on 400 KV Bus - II at 13:52 Hrs.
After yard observation, 400 KV Bus coupler and Bus - 1 was charged at 14:05 Hrs and 500
MVA ICT was taken in service at 14:08 Hrs.
Page 1 of 3
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The details of tripping of lines, ICTs along with duration of interruption and relay operation are
shown below:
Sr. Name of line/ Equipment Tripping Time Relay Indications
No. Hrs.
From To
08:19 CGPL end: DT receive, Jetpur end: Z1 Y-
1 400 KV CGPL - Jetpur Line No. 2 13:24
(02.09.14) B, Bus bar Z1 optd
Amreli end: Z1 L2-L3, Jetpur end: Bus bar
2 400 KV Amreli – Jetpur Line No. 1 13:24 15:12
Z1 optd
400/220 KV 315 MVA ICT – 3 at
3 13:24 15:05 HV side: Y-B fault. LV SIDE : 86 Operated
Jetpur S/S
400/220 KV 500 MVA ICT – 4at
4 13:24 14:08 HV side: Y-B fault. LV SIDE : 86 Operated
Jetpur S/S
7. Sequence of restoration:
400 KV Amreli – Jetpur line No. 2 was taken in service on 400 KV Bus-2 at 13:45 Hrs.
400 KV CGPL – Jetpur line No. 1 was taken in service on 400 KV Bus-2 at 13:52 Hrs.
After ensuring healthiness of 400 KV Bus-1, 400 KV bus coupler was charged at 14:05 Hrs.
400/220 KV, 500 MVA ICT was charged at 14:08 Hrs.
400/220 KV, 315 MVA ICT was charged at 15:05 Hrs.
Prior to incident, both the 400 KV EHV lines of Main bus – 2 were out under HV off. At least,
one 400 KV EHV line on each 400 KV bus shall be in service.
Thanking you,
Yours faithfully,
Sd/-
(B. B. Mehta)
Chief Engineer (SLDC)
Page 2 of 3
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Annexure – 2.2
Detailed report on the grid disturbance at 220 kV Magarwada S/s, DD on 4 September 2014.
th
1. Event Summary : At 12:44 Hrs, 220 kV Vapi(PG)-Magarwada circuit 1 tripped on R Phase to earth
fault which resulted in loss of power supply to DD. 220 kV Vapi(PG)-Magarwada 2 circuit was already
out due to tripping on Y-B phase to phase fault at 10:03 Hrs. This has resulted in loss of DD loss in tune
to 174 MW.
Figure 2 : 400 kV Bus of 400/220 kV Vapi (PG) Sub-station SLD at 12:40 Hrs
Figure 3 : 220 kV Bus of 400/220 kV Vapi (PG) Sub-station SLD at 12:40 Hrs
3. Event Overview:
Prior to the event of 12:44 Hrs, 220 kV Vapi (PG)-Magarwada circuit 2 was already out
since 10:03 hrs in the morning due to tripping on Y-B Phase to Phase fault. The line was
under patrolling.
At 12:44 Hrs, the Vapi (PG)-Magarwada circuit 1, which was carrying a load of around
180 MW tripped on B Phase to earth fault. This has led to loss of incoming power to
220/66 kV Magarawada S/s causing total disruption of power supply at DD.
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Load / Generation affected: Load loss of around 174 MW occurred during the event.
Frequency Change : Freqiency has rose by 0.03 Hz i.e. from 50.00 to 50.03 Hz during teh event. Power
number comes out to be 5800 MW/Hz. Energy not served was around 78 MWhr during the event.
Restoration: 220 kV Vapi (PG) –Magarwada 1 was restored at 13:13 Hrs and 220 kV Vapi (PG) –
Magarwada 2 was restored at 13:26 Hrs.
5. Analysis: So it can be observed that loss of evacuation line has resulted in loss of DD load from the
grid and blackout in the Area. The DR and Event logger were not provided also preliminary report
has not come from the utility. PGCIL may specify the reason of line tripping of fault.
Remarks: Establishment of 400/220 kV Magarwada GIS sub-station will improve the contingency
situation and strengthen the system at DD.
Yours truly,
Abhimanyu Gartia
Dy. General Manager (MO-II & III & SL)
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Annexure - 2.3
Sub: - Operation of LBB protection at 220 KV Paras substation on 04.09.2014 – Analysis thereof.
Ref: - 1) No. EE/Testing/Ytl/Tech/G-12/461 Dt. 06.09.2014
2) E-mail from GENCO Paras. Dt. 06.09.2014
1. Occurrence details:
The station TF-1 at 220 KV Paras substation was under outage from 02.09.2014 for maintenance
works. While charging the said TF on date 04.09.2014 at 18:52 hrs, the O/C, EF and the LBB relay of this bay
operated at GENCO end and the 220 KV CBs of all the bays connected to Bus-1 tripped. The details of the
CBs tripped and the relay indications are shown in the table below:
The single line diagram showing the details of CB tripped is enclosed herewith for reference.
2. Investigation/Analysis:
1. The 220 KV CB of the Station TF-1 is checked, immediately after the occurrence in the presence of
GENCO authorities, for proper opening operation and found to have opened correctly.
2. The DCRM of CB is carried out & CB operation timings are measured in the presence of GENCO
authorities and found satisfactory. The results are as below:
Measurement R pole Y pole B pole
Closing time 144.4 m sec 144.9 m sec 144.6 m sec
Tripping time 22.1 m sec 21.3 m sec 22.7 m sec
CO time 178.7 m sec 177.4 m sec 179.1 m sec
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3. The DR (disturbance record) of the bus bar relay and that of the O/C EF + LBB relay of Station
TF-1 at GENCO end is retrieved. The DRs are enclosed herewith for ready reference. The following observations
are made from the above DRs.
i) The b/u relay of the Station TF-1 is under the control of MSPGCL Paras. The DR of this relay is
retrieved in coordination with GENCO authorities. This DR indicates the values of TF inrush current 100 msec
pre pickup and 100 msec post pickup of back-up relay operation. No output relay is seen to have picked up
during this 200msec. The instant of operation of any of the relay, the O/C, the EF or the LBB, is not indicated
by this DR. Further the instant of operation of the 86 relay is also not available.
ii) The DRs of the bus bar relay for all affected bays reveal that- the CBs of all the bays, other than the
Station TF-1 bay, have tripped after the operation of the 96 relay of the concerned bay. But the CB of the Station
TF-1 bay had tripped before the operation of its 96 relay. This indicates that the other protections (i.e. O/C, EF or the
LBB) had operated prior to the operation of 96 relay. The exact instant of the receipt of trip command is not
indicated by the b/u relay. The fact, that the CB trips correctly within the specified time and that there is no
problem with mechanism for CB operation, has been established by measurement of trip time of the CB. That the CB
at the time of occurrence has correctly opened is also established by immediate inspection of the CB. There is no
reason to believe that the tripping of the CB is delayed as much as to initiate LBB relay.
iii) The DR of the b/u relay of this TF is not conclusive and does not indicate whether the trip is issued by
the O/C relay, EF relay or the LBB relay. Since the CB has tripped well within the specified trip time, there is
no reason why the LBB relay should operate even after the correct tripping operation of the CB.
iv) It was also informed that the b/u relay (i.e. the O/C, EF + LBB) was not getting reset even after the
tripping of the breaker and the current through that relay had ceased to zero. This further substantiates the claim that
there is some problem at GENCO end.
It is later confirmed from the email of the GENCO authorities that the trip relay 86 ST and its CMR 86
STX were found malfunctioning & these relays have been replaced. The Station T/F-I charged on 06.09.2014 at
19:45 Hrs.
Area affected: -
Area affected – Nil.
GT-2 affected- 167 MW
Remedial measures:
i) DR of Back-up relay of Stn T/F-I (at generation side) is not indicative as the length of DR is
set for total 200 msec i.e. 100 msec pre pickup & 100 msec post pickup and hence the occurrence
cannot be properly analysed.
In order to analyze the occurrence the DR time setting should be reviewed by GENCO
Authorities.
ii) It is noticed that this particular TF trips on EF relay while charging and it generally takes
more than one attempt to charge it successfully. This needs to be investigated by GENCO authorities.
The b/u relay of this TF needs to be tested for accuracy of operation of all its enabled features. It is
also felt that relay settings of EF relay are too sensitive and need to be reviewed and revised.
Encl: 1 The DR of the Bus bar relay for all the affected bays.
2. The DR of the b/u protection relay of the Station TF-1
(obtained from GENCO Paras)
3. Single line diagram.
SD/-
SUPERINTENDING ENGINEER
TESTING & COMMUNICATION CIRCLE
MSETCL, AKOLA
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Single Line Diagram of 220 KV Paras S/Stn. (Ref-Occurrence dated 04.09.2014 )
OC/EF + LBB
Operated
Station Gen.
Akola-1 T/F-1 Chikhali-1 T/F-2 Balapur-1 Balapur-4
Main bus-I
Bus Coupler
Main bus-II
Transfer
Bus
CB Not Tripped
CB Tripped
CB Already Open
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Annexure - 2.4
Report on SSR phenomenon at APL Mundra on 5th and 6th September 2014
Event: SSR phenomena at APL Mundra on 5th and 6th September 2014.
Time: 10:53 Hrs- 13:00 Hrs, 13:30 Hrs-16:00 Hrs, 19:20 Hrs-19:42 Hrs on 5th sept and 09:20 Hrs-9:40 Hrs. 15:45-16:07 Hrs on
6th September 2014
Antecedent Condition: At APL Mundra only one 330 MW unit was in service. All the lines and ICTs from Mundra were in
service. The HVDC power order was being regulated between 1000-1200 MW. The FSC on 400 kV APL-Sami lines were kept
out.
Event Summary:
At 10:48 Hrs on 5th September 2014, 400 kV APL-Sami 1 line was hand tripped to regulate high voltage scenario. This was
followed by sub-synchronous oscillation at AML Mundra resulting in oscillation in 400/220 kV voltages. The Voltage plots of
APL Mundra Bus is given which indicate the various duration during which SSR was observed at Mundra.
It was found that only slight voltage variation were observed at CGPL Mundra from the PMU during the period. It
indicates that the phenomenon was local to APL Mundra.
Voltage variation in the range of 3-4 kV was observed in each phase of APL Mundra in all the durations. Current of the 400
kV APL-Sami 2 and APL-Hadala were also oscillating with higher range i.e. 74 Amp and 25 Amp respectively.
The frequency of oscillation is more than 12.5 Hz therefore could not be measured with the synchrophasor data having
reporting rate of 25 Hz.
The voltage and current observed are in opposite phase with each other as per the data from PMU. Even though the
oscillation frequency could not be determined as aliasing will occur (if frequency exceed the half of the sampling rate resulting
in superimposition over same signal), the phase difference can be observed. The DR from site is required for further validation
as such scenario may result in power swing scenario. Here the voltage fluctuation was comparatively low , so possibility of
power swing will not be present.
The oscillations have prevailed for longer duration of time on 5th September 2014.
Even on the 6th September SSR were observed for shorter duration.
Analysis:
The SOE obtained from Mundra for 5th September indicate that SSR Damping control activated at 10:48:04 Hrs and it is
observed that oscillation also started at the same time. Whether the damping controller was responsible for oscillation to
aggravate need to be further investigated. If the damping controller was acting to damp the oscillation then it is clearly
understood that it need further tuning as oscillation has even persisted for longer duration.
As per SSR Damping Controller Event Log:
At 19:43 Hrs, Filter 10CF32 switched off in auto mode as per RPC (Reactive Power Control) requirement due to HVDC
power ramp after which SSR was not observed.
On 06-09-14 at 09:41 Hrs, Filter 10CF22 switched off in auto mode as per RPC (Reactive Power Control) requirement due
to HVDC power ramp after which SSR was not observed.
On 06-09-14 at 15:55 hrs , HVDC power ramp has resulted in diminishing the SSR
So it was confirmed that SSR activity was going at APL Mundra sub-station. As the FSC on 400 kV APL Sami Circuits
were out, so the phenomenon was associated with the Sub-synchronous torsional interaction (SSTI) of HVDC. Also the HVDC
SSR damping controller has acted. It was observed that with change of the alpha i.e. with change of HVDC power order, the
SSR was getting damped out which also specifies the nature of SSR.
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PMU Plots
Figure 1 : Voltage of APL Mundra Bus between 10:30-11:30 Hrs on 5th September 2014
Figure 2 : Voltage of APL Mundra Bus between 09:10-09:50 Hrs on 6th September 2014
Remarks:
It was observed that SSR due to HVDC controller is present at the APL Mundra sub-station.
This is the second case of SSR phenomena, earlier it was observed on 30th May 2014 when SSR protection resulted in
blocking of both HVDC pole and tripping of Unit 7 and 9.
It was mentioned in the report shared by APL Mundra for Sub-synchronous damping controller that only 660 MW units
were considered for studies. There is a need to review the controller setting which should include 330 MW units along with
660 MW Units. APL Mundra is requested to kindly look into the matter and take remedial measures.
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Annexure - 2.5.a
Grid Incidence at SSP on 9th September 2014
Event: At 14:25:20 Hrs, LBB of 400/220 kV ICT 1 at SSP operated which has resulted in Bus Bar
protection operation for 400 kV Bus 1 at SSP. This led to tripping of all elements connected at 400 kV
Bus 1 at SSP. The ICT tripping has caused the tripping of 220 kV Bus 1 at SSP as the Bus coupler at
220 kV is kept in open condition. The event has resulted in tripping of Unit 1 ,3 5 on 400 kV side (
River bed power house, RBPH) and Unit 1, 3 on 220 kV side (Canal head Power House, CHPH)
resulting in loss of total generation loss of around 590 MW.
Antecedent Condition:
400 kV and 220 kV Bus at SSP is having Double Bus single breaker Scheme (Figure 2).
At 13:39 Hrs: 400 kV SSP-Dhule 1 was hand tripped to control the high voltage.
At 14:23 Hrs : 400 kV SSP-Rajgarh 1 was taken in service .
At 400 kV SSP (River bed power house, RBPH) All Units were in service.
At 220 kV SSP (Canal head Power House, CHPH) All unit in service except Unit 3.
Event Analysis:
At 17:25:18 Hrs: B phase to earth fault occurred on 400 kV SSP-Rajgarh 1. Line got reclosed
after 1 second in zone 1 carrier aided protection.
At 17:25:20 Hrs: 400/220 kV ICT opened and its R and B Phase got opened while Y phase got
~1~
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stuck on 400 kV Side. This has resulted in stuck breaker condition causing LBB operation for
circuit and subsequently Bus Bar protection for 400 kV Bus 1.
With this all connected elements on 400 kV Bus 1 tripped.
Table 1 : Sequence of events
DR Analysis
Even after communication and instruction, SSP and PGCIL WR-2 has not send the DR
associated with the event. Only DR received from the SSP was for the 400 Rajgarh 1 circuit
trip where also the duration is only for the fault time and not for the reclosure time.
DR from SSP end for the SSP-Rajgarh 1 indicate that fault has occurred in B phase of the line
at 14:25:18.770 and fault location was around 111 km. Therefore, it was observed in zone 1
and carrier was sent and received for the tripping.
It was found from the PMU plot of frequency and voltage that the line tripping and ICT
opening causing breaker issue were two different events with a gap of 2 seconds.
It is also observed from PMU that after the fault on 400 kV SSP-Rajgarh 1, the line got closed.
So the reason for opening of ICT breaker from HV side is still not known which has resulted
in LBB operation as it Y phase could not opened. This resulted in initiation of Bus Bar
protection for 400 kV Bus 1 at SSP.
SSP/NCA need to take immediate action for the assuring the reliable and selective protection
system at SSP sub-station.
In addition, it was found that, SCADA data of 220 kV is not available at WRLDC, which further
needs to be relooked.
During analysis it was found that, there is no protection scheme installed for the lines
connecting the 220 kV outlet of ICT at RBPH to 220 kV Bus of CHPH. This is very endangering
situation. Proper protection scheme need to be installed so that fault of 220 kV should not
propagate to 400 kV levels. SSP/NCA need to take immediate action
Remarks:
SSP/NCA should send the detailed analysis of cause of opening of ICT breaker, which has
resulted in LBB and Bus Bar protection operation due to stuck breaker condition.
MPPTCL should take immediate action for the patrolling of the 400 kV SSP-Rajgarh D/C and
assure its healthiness. In addition, they are advised to submit the report on the vary cause of
the line tripping which may be either vegetation or insulator failure.
SSP/NCA and PGCIL WR-2 are advised to send the DR and event logger of the lines whenever
they trip within 24 hours of the incident. The DR and Event logger must be in comtrade
format so that analysis could be done easily.
~2~
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Annexure - 2.5.b
Pre-Fault Condition
On dated 10.09.2014 at around 00:15 Hrs MP System was normal and frequency of
National Grid was 49.68 HZ. At 400 KV S/s Indore, all 400 KV & 220 KV feeders were in
charged condition and normally loaded.
For load management following feeders are kept open:-
1. 220 KV Indore – South Zone Ckt – III (Tap from 220 KV Indore – Jetpura Ckt – I) was
open from 220 KV S/s South Zone.
2. 132 KV WZ Indore – Pithampur Ckt. was open from 132 KV S/s Pithampur end.
3. 132 KV Pithampur – Rau(tap STI) Ckt. was open from 132 KV S/s Pithampur end.
4. 132 KV Chambal – NZ Indore Ckt. – I & II was open from 132 KV S/s Chambal end.
5. 132 KV Simrol – Barwaha Ckt. was open from 132 KV S/s Simrol end.
6. 132 KV South Zone – Barwaha Ckt was open from 220 KV S/s South Zone end.
7. 132 KV Ghata Billod – Dhar was open from 132 KV S/s Dhar.
From the above information it can be gathered that load of 132 KV S/s Simrol, Rau, STI,
CAT, West Zone, Ghata Billod, Chambal, Satya Sai & Manglia was on 132 KV S/s SZ.
Feeder arrangement at 400 KV S/s Indore prior to fault
S.No. On 400 KV Main Bus – I S.No. On 400 KV Main Bus – II
1. 400/220 KV, 315 MVA, ICT – I & III. 1. 400/220 KV, 315 MVA, ICT – II & IV.
2. 400 KV Indore – Asoj (Gujarat) Ckt – III. 2. 400 KV Indore – Indore(PG) Ckt – II.
3. 400 KV Indore – Itarsi Ckt – I. 3. 400 KV Indore – Itarsi Ckt – II.
4. 400 KV Indore – ISP Ckt – I. 4. 400 KV Indore – ISP Ckt – II.
5. 400 KV Indore – Asoj Ckt – II. 5. 400 KV Indore – Asoj Ckt – I.
6. 400 KV Indore – Nagda Ckt.
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Remedial Measures
Supply at 132 KV S/s Chambal was resumed by charging 132 KV Chambal – North
Zone Ckt – I & II at 00:28 Hrs. Thereafter supply was extended to 132 KV S/s Satya Sai & 132
KV S/s Electronic Complex through following links:-
Time in Hrs.
S.No. Name Of Feeder/Transformer
Tripping Charging
1. 132 KV Chambal – Satya Sai Ckt 00:20 00:28
2. 132 KV Chambal – Electronic Complex 00:20 00:28
Supply at 220 KV S/s South Zone was resumed by charging 132 KV Barwaha – South
Zone Ckt at 00:29 Hrs. and simultaneously following feeders were charged:-
Time in Hrs.
S.No. Name Of Feeder/Transformer
Tripping Charging
1. 132/33 KV, 40 MVA X’mer – IV at 220 KV S/s SZ. 00:20 00:30
2. 132 KV South Zone – CAT Ckt – I & II. 00:20 00:30
3. 132/33 KV, 40 MVA X’mer – III at 220 KV S/s SZ 00:20 00:31
4. 132 KV South Zone – Rau Ckt. 00:20 00:32
5. All 33 KV feeders at 220 KV S/s South Zone. 00:20 00:33
220 KV supply at 220 KV S/s South Zone was resumed by
6. 00:20 00:37
charging 220 KV Jetpura (Indore II) – South Zone Ckt.
7. 220/132 KV, 160 MVA X’mer – III at 220 KV S/s SZ. 00:20 00:39
8. 220/132 KV, 160 MVA X’mer – IV at 220 KV S/s SZ. 00:20 00:41
9. 132/33 KV, 40 MVA X’mer – I at 220 KV S/s SZ. 00:20 00:42
10 132/33 KV, 40 MVA X’mer – II at 220 KV S/s SZ 00:20 00:43
11. 132 KV South Zone – Simrol Ckt. 00:20 00:47
12. 220/132 KV, 3X40 MVA X’mer – I at 220 KV S/s SZ. 00:20 00:48
13. 132 KV Rau Khedi – MSP Ckt. 00:20 00:48
14. 132 KV South Zone – Rau Khedi Ckt (Tap Manglia) 00:20 00:48
15. 220/132 KV, 3X40 MVA X’mer – II at 220 KV S/s SZ. 00:20 00:50
Supply at 132 KV S/s West Zone was resumed by
16. 00:20 00:50
charging 132 KV West Zone – Pithampur Ckt.
Supply at 132 KV S/s Ghata Billod was resumed by
17. 00:20 01:00
charging 132 KV Ghata Billod – Dhar Ckt.
At 400 KV S/s Indore, 220 KV Main Bus – I was charged by charging 220 KV Indore – Barwaha
Ckt – II at 00:58 Hrs. Subsequently following feeders/transformers were charged:-
1. 220 KV Bus Coupler Breaker at 01:02 Hrs.
2. 220 KV Dewas – Indore East Ckt – at 01:03 Hrs.
3. 400/220 KV, 315 MVA, ICT – I & II at 400 KV S/s Indore – at 01:04 Hrs.
4. 220 KV Indore – Indore II (Jetpura) Ckt – I from 400 KV S/s Indore – at 01:07 Hrs.
5. 220 KV Indore – South Zone Ckt – II – at 01:08 Hrs.
Conclusion
The tripping occurrence as Earth Wire of 220 KV Indore – South Zone Ckt – I snapped and
simultaneously coil of ‘Y’ – Phase pole of circuit breaker burnt at 400 KV S/s Indore which
resulted in operation of LBB protection.
The operation of LBB of 220 KV Indore – South Zone Ckt – I which initiated the operation
of Bus Bar Protection is found to be in order.
‘Y’ – Phase breaker coil of 220 KV KV Indore – South Zone Ckt – I replaced and feeder
charged at 15:42 Hrs. on 10.09.2014.
The cause of burning of ‘Y’ – Phase coil of Main CB needs to be investigated. Hence
correspondence with M/s Alstom is under process.
Load Loss
There was a Load Loss of approximate 187.4 MW, 53.95 MWH for approx. 30 Min
during the above tripping.
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Annexure - 2.6
Sub: Report on grid disturbance occurred in Gujarat system on 15.09.14 at 12:44 Hrs.
On 15/09/14 at 12:44 Hrs, grid disturbance occurred in Gujarat Power System. It led to load loss of around 190 MW at 220
KV Vapi S/S.
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Annexure - 2.7
Event Summary: At 05:37 Hrs, All the running units from Uran tripped due to problem with the Gas
skid system. This has resulted in tripping of Uran Unit 5, 6, 7, A and B.
The Uran Units tripping event was analyzed based on available information at WRLDC end only and
Maharashtra SLDC daily report. It was reported that 05:37 Hrs Uran Unit 5, 6, 7, A0 and B0 have
tripped on gas skid problem. The frequency dropped due to tripping of generation by 0.0455 Hz
which indicate a loss 273 MW generation (calculated from 6000 MW/Hz power number).
A Gas Conditioning Skid is designed to pre-treat natural gas and other combustible gasses prior to
injecting into a critical process or a Gas Turbine Generator. The skid performs two functions; remove
all liquid droplets and solid contaminants from the gas, and adjust the gas temperature to the
injection requirements. If the above system has any issue, the supply of gas will not be there to the
combustion chamber causing tripping of turbines.
Remarks: Such multiple tripping of generating units falls under GI-1 category and complete details of
the event need to be shared with the SLDC/WRLDC/WRPC. Such events are also need to be analyzed
to reduce the number of such events in future. MSEGCL is requested to kindly send the detailed
report of the above incident and any occurrence in future also
~1~
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Annexure - 2.8
Detailed report on the blackout at 400 kV JP NIGRIE Sub-station on 17th September 2014
5. Event Overview:
JP-Nigrie is an IPP in Western region grid having a capacity of 660X2 MW. As of now one unit has
been COD at the JP Nigrie. Prior to the event, JP Nigrie was connected with WR Grid through
LILO arrangement of 400 kV Vindhyachal-Satna circuit 4.
Planned lines of JP-Nigrie were from 765 /400 kV Satna Station. Prior to the event, both lines
from Satna Sub-station were commissioned and in service and LILO arrangement were removed.
The single line diagram of the station is shown in figure 1 prior to the event. The Bus Reactor Dia
tie CB was kept in open condition during the event. Also the Tie CB of Stana Circuits Dia was not
complete and Tie CB was not commissioned as informed by JP Nigrie.
At 19:47 Hrs, B Phase to earth fault occurred on 400 kV JP-Nigrie-Satna 2 circuit and it tripped
from both end immediately without auto-reclosing of the circuit. At the same time due to relay
coordination issue, Generator Main and Tie CB also has tripped. This resulted in isolation of Bus
1 and Bus 2 as the Tie CB of Unit 1 GT was connecting these two buses.
The supply to 400 kV Bus 1 got tripped due to isolation while supply to Bus 2 remained as 400 kv
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Load / Generation affected Due to tripping of JP Nigrie Unit 1, around 335 MW generation was lost
from the grid.
Restoration: Restoration started by closing the Bus reactor Bay and supplying power to ST-1. After that
Line 2 was taken back in service at 00:45 Hrs on 18th September 2014 and Unit was synchronised at
06:18 Hrs.
7. Analysis: Here root cause of the tripping can be summarised as following :
1. Incomplete Dia in one and half breaker scheme.
2. Keeping Tie circuit breaker open in the one and half breaker scheme.
3. Not keeping auto-reclosure in service for single-phase fault.
4. Issue with relay coordination resulting in tripping of generating unit.
9. Remarks:
The event has taught many lessons which any entity should adhere out of which the
important one is to keep all breakers in service in one and half scheme to improve the system
redundancy.
JP Nigrie and PGCIL are requested to send the DR/EL in the timeline specified by the IEGC and CEA grid
standard for accelerated analysis of the event.
Yours truly,
Abhimanyu Gartia
Dy. General Manager (MO-II & III & SL)
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Annexure - 2.9
Sub.:- Details of Tripping at 400 KV Korba West station on 19/09/2014 at 12:55:49 Hrs.
1. Event Summary:
On 19.09.2014 at 12:55:49 hrs, running units at HTPS 400 KV system i.e. Unit#3(210 MW), Unit #4 (210
MW) & Unit#5 (500 MW) and 400 KV HTPS-KSTPS, 400 HTPS-Khedamara 1 and 2,500 MVA 400/220
KV ICT tripped with heavy jerk. As reported by the station, one tension string of ‘B’ phase Bus no.-I near
bay no.-II was found shattered and fell down, also damaging other parallel tension string of same location.
Marks of flash over was observed on discs of tension string. It seems that the incident of failure of tension
string has taken place due to lightening because weather was cloudy and thundering and frequent lightening
was taking place during that time.
The incident comes under GD -5 category as per CEA regulation on grid Standard 2010 as there was loss of
generation for more than 40% of antecedent generation in CG system.
2. Event Overview:
Prior to this tripping, the generating unit no. 3, 4&5 and 400 KV HTPS-KSTPS, 400 HTPS-Khedamara 1
and 2 and 500 MVA 400/220 KV ICT were on Main Bus No.2 and Main Bus no. 1 and 400 KV HTPS-Raita
line were under permit for replacement of R & Y phase isolators. After cancellation of permit, charging code
no. 1836 was issued to ECR at 12:06 hrs for charging of the same. Main Bus-1 was charged at 12:44 hrs.
The sequence of Tripping and restoration time with indication as per data from SLDC SCADA is as follows:
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1
Load / Generation affected: During the incident, running units at HTPS No #3(210 MW), Unit #4
(210 MW) & Unit#5 (500 MW) tripped resulting generation loss of about 749 MW. Demand before
tripping was 2699MW which increased by to 2877 MW.CG OD increased from 87 to 772 MW which
was controlled immediately by raising the generation at DSPM by about 100 MW and enforcing
Load shedding to the tune of about 600 MW. The OD was gradually contained to 200 MW by 13:30
hrs and 100 MW by 13:45 hrs.
Total Interruption Time at 400 KV system at HTPS : 06Hr & 29 Min.
3. Restoration Sequence:
19:25
Main Bus-II charged through ICT
19:33
400 KV HTPS-Raita charged from Korba end
19:34
400 KV HTPS-Raita charged from Raita end
19:42
Unit no.4 Synchronized with the system
20:00
Station Transformer No. 5A Charged
20:05
Station Transformer No. 5B Charged
23:58
Unit no.3 Synchronized with the system
20.09.2014
10:55
400 KV HTPS-KSTPS charged from Korba end
11:06
400 KV HTPS-KSTPS charged from KSTPS end
11:15
400 HTPS-Khedamara 1 charged at Korba end
11:18
400 HTPS-Khedamara 1 charged at Khedamara end
11:29
400 HTPS-Khedamara 2 charged at Korba end
11:32
400 HTPS-Khedamara 1 charged at Khedamara end
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KWB 400KV
G DSPMTPS
2x210 MW
G G
2 x 250 MW
G
PATHADI
SIPAT
PGCIL BHATAPARA
RAITA
RAIPUR
PGCIL BHILAI (KHEDAMARA) 400 KV
Analysis:
As reported by SE (ET &I-II), CSPGCL, Korba West, the failed and existing tension/suspension
isolators are more than 30 years old hence the possibility of weakening of its insulation properties
may be the cause of failure.
It was also proposed by the site that existing insulator strings will be tested and replaced in phased
manner in the future.
The diagram of HTPS switchyard and failed string along with DR &EL of numeric relays of 400
KV HTPS-KSTPS feeder As received from Korba West are also enclosed.
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Annexure - 2.10
Sl Name of Name of the bay Date and Date and Area Remark
no. the tripped due to time of the time of affected
substation operation of bus tripping restoration
bar relay
220 KV Warora 21.09.2014 21.09.2014 NIL Tripped on
1. feeder – 1012 hrs –1036 hrs operation of
bus bar
220/33 KV 50 MVA 21.09.2014 21.09.2014 Area fed protection
TF-2 – 1012 hrs –1041 hrs by 4 nos
2. 220 KV of 33 KV
relay (REB
Wani S/stn feeders 500) due to
220 KV Bus section 21.09.2014 21.09.2014 NIL failure of
CB – 1012 hrs -- 1035 hrs B-phase PT-II
3. of 220 KV Bus
Section II
B) Investigation/Analysis:
1. The PT is suspected to have failed due to insulation failure.
2. Due to failure of B ph PT II of 220 KV Bus Section II at 220KV Wani S/Stn., it causes the bus fault on section
II of 220 KV Bus. The operation of Bus bar is in order. As 220 KV Wani Warora line and 220/33 KV TF II are on
same bus section, the tripping of the said line & TF is correct and in order. Also the tripping of Bus sectionalizer on
BB is in order as it saved the other half Bus Section.
3. This PT does not have the tan delta point. The measurement of C and tan delta on GST mode was carried out but
the test results obtained were erratic, means the results were too high and inconsistent. The results, therefore, were
not conclusive.
4. Details of failed PT: Make – S.C.T. Gaziabad, Rated voltage- 245kV, Sr. No. - 2289/08, Yr of
Mfg.- 2008, Commissioning date – 10.06.2010.
C) Area affected:
Area fed from 33 KV feeders connected to the LV of TF II are affected for 29 min. Load Before trip 9.3 MW.
D) Remedial measures:
1. The PT supply of Bus-1 PT is extended to affected feeders and the supply is restored.
2. The PT has been replaced by new PT on Dt. 24.09.2014. Make : SCT Gaziabad. Sr. No.
118/2010. YOM-2010.
3. The failure of PT in short span is not desirable. Hence matter should be referred to the manufacturer. The
SCT make PT’s are not having Tan Delta point and gives erratic Tan Delta results in GST mode. Also the pre-
commissioning Tan Delta results are not available. Hence the healthiness of PT cannot be ascertained due to
unavailability of testing results.
It is suggested that while procuring PT, the availability of Tan Delta point may please be explored, so
that testing can be carried out to ensure the healthiness of PT.
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B Phase PT-II of
PT -I bus section failed
220 KV Bus
sectionalizer C.B.
33 KV Bus
CB Open
33 KV 33 KV 33 KV 33 KV 33 KV 33 KV 33 KV
Lalguda I Cotton Shindola RPL Urja Kolar Rajur Lalgadi
Market Pimpri
CB Open
47
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Annexure - 2.11
Report on Voltage Fluctuation observed throughout the Western Grid
Event: Voltage fluctuation observation throughout the Western Grid.
Time: 13:47 Hrs- 14:04 Hrs 21-09-2014
Event Summary: Voltage fluctuation at a regular fixed interval at 11 seconds was observed in Western
region. These fluctuations were dominant around Bhadrawati PMU. After looking at the aspect, the HVDC
Bhadrawati Power flow was reduced by 300 MW in real time to look whether the event is due to HVDC
bhadrawati. The fluctuations were observed at regular interval of 11 seconds as seen in the voltage plot. In
addition, the small fluctuations were observed in Current and Active Power flow.
Analysis of the Event: As initially, none of the units have reported any problem to WRLDC control room.
The phenomenon was more observable around 400 kV Bhadarwati Sub-station. Therefore, the problem
was thought to be related to Convertor terminal of HVDC Bhadrawati or HVDC Chandrapur- Padghe.
However, on enquiry no abnormality was found at that instant at both these stations. It was found that
Mauda Unit 2 was hand tripped at the 13:47 Hrs on ETW Pump Failure. After that Unit 1, reactive power
absorption (30 MVAr to 8 MVAr) started reducing and its active power was increased (350 MW to 450
MW).
It was also found that after 14:07 Hrs, the reactive power absorption was suddenly increased from
8 MVAr to 55 MVAr. It seems that there is issue with the reactive power controller of the Mauda Unit, which
has resulted in the voltage fluctuation across the grid. NTPC has yet to give their analysis on the event.
Remarks: In view of the above NTPC is requested to analyze the event in detail and send a report to
WRLDC/WRPC regarding the issue. Such event should be analyzed in detail. The data received from
Mouda end was of low resolution and no analysis could be done that. Station may have the data for
at least 1-second resolution as observed in all the new commissioned station SCADA, which could give
a better overview. In addition, the event loggers for the Units were also not received.
49
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Annexure - 2.12
On dated 23.09.2014 at around 13:50Hrs. M.P System was normal and frequency of
National Grid was 49.83Hz.
At 220 KV S/s Chhindwara all 220 KV and 132 KV feeders were in charged condition
and normally loaded.
Due to the above tripping there was no consumer load loss and 132KV supply was
available as 132KV System at 220KV S/s Chhindwara was intact. There was no generation
loss and System was normalized in due course of time (Relay indication and Charging time
of ICT & feeders enclosed).
50
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1
PGCIL-II 3KM
Kalmeshwar 64KM 132KV S/S Borgaon
160Mva CGL
220KV Bus
132KV Bus
132KV S/S Bichhua
160Mva AREVA
51
1
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Annexure - 2.13
52
1
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53
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54
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55
1
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Annexure - 2.14
Pre-Fault Condition
On dated 30.09.14 at around 17:30 Hrs. MP System was normal and frequency of National Grid was 49.84 HZ.
At 220 KV S/s Pithampur, 132 KV Pithampur – Mid India Ckt (Industrial Feeder) was open and 132 KV Pithampur –
Bhanu Steel (Industrial Feeder) was not in service. Remaining all 220 KV & 132 KV feeders were in charged condition and normally
loaded. At 220 KV S/s Pithampur Double Main Transfer (DMT) Bus scheme exists and all 220 KV feeders & X’mers were charged
through their main breaker i.e., 220 KV Bus Tie at 220 KV S/s Pithampur was available.
Feeder arrangement at 220 KV S/s Pithampur prior to fault was (‘+ive’ export & ‘-ive’ import):-
MW MW
S.No. On 220 KV Main Bus – I S.No. On 220 KV Main Bus – II
Loading Loading
1. 220 KV Interconnector – II -105 1. 220 KV Interconnector – I -105
3. 220/132 KV,160 MVA X’mer – I. 114 3. 220/132 KV,160 MVA X’mer – II 114
Occurrence
At 17:33 Hrs. ‘B’-Phase CT of 220/132 KV, 160 MVA X’mer – II at 220 KV S/s Pithampur burst creating the 220 KV bus
fault , resulting in operation of Bus Bar Protection of 220 KV Main Bus - II. Consequently following feeders and X’mers (connected
to 220 KV Main Bus – II) tripped:-
1. 220/132 KV, 160 MVA X’mer at 220 KV S/s Pithampur.
2. 220 KV Pithampur – Rajgarh(PGCIL) Ckt – II.
3. 220 KV Interconnector – I & II.
220 KV Interconnector – II which was on 220 KV Main Bus – I at 220 KV S/s Pithampur tripped from 400 KV S/s
Pithampur end on ‘B’-Phase, Zone-II, Dist-26.8 km indication due to jerk.
Due to the tripping of 220/132 KV 160 MVA X’mer – II, its complete load shifted on 220/132 KV, 160 MVA X’mer – I
resulting in overloading of X’mer – I and in operation of its Load Drop scheme. Consequently 132 KV Jamli, 132 KV Betma, 132
KV Bagdi, 33 KV Metal Man – I&II and 33 KV Novino feeders tripped under operation of Load Drop Scheme at 220 KV S/s
Pithampur.
Due to the above tripping interruption occurred at 132 KV S/s Jamli, 132 KV S/s Betma & 132 S/s Bagdi as these sub-
stations are radially connected to 220 KV S/s Pithampur.
The relay indications appeared in various transmission elements provided by the Executive Engineer Testing Division - II,
MPPTCL, Indore is enclosed as annexure – I. The DR file provided is not in proper format hence cannot be accessed.
Remedial Measures
After reducing the load of 220 KV S/s Pithampur (to avoid overloading of 220/132 KV, 160 MVA X’mer – I) by diverting
the load of 132 KV S/s Pithampur on 220 KV S/s South Zone Indore and taking back 33 KV feed supply for 132 KV S/s Jamli, 132
KV S/s Bagdi and 132 KV S/s Betma following 220 KV & 132 KV feeders were charged:-
1. 220 KV Interconnector – II – at 18:25 Hrs.
2. 33 KV Metal Man – I & II (Industrial feeder) at 220 KV S/s Pithampur – at 18:40 Hrs.
3. 33 KV Novina Ckt. (Industrial feeder) at 220 KV S/s Pithampur – at 18:40 Hrs.
4. 132 KV Pithampur – Jamli (Radial feeder) – at 18:45 Hrs.
5. 132 KV Pithampur – Betma (Radial feeder) – at 18:45 Hrs.
6. 132 KV Pithampur – Bagdi (Radial feeder) – at 18:45 Hrs.
7. 220 KV Interconnector – I – at 18:52 Hrs.
8. 220/132 KV, 160 MVA X’mer – II at 220 KV S/s Pithampur was charged after replacement of ‘B’-Phase burst CT at
09:00 Hrs. on 10.09.2014.
Conclusion
The above tripping occurred as ‘B’-Phase CT of 220/132 KV, 160 MVA X’mer – II burst at 220 KV S/s Pithampur.
220/132 KV, 160 MVA X’mer – II at 220 KV S/s Pithampur was charged after replacement of ‘B’-Phase burst CT at 09:00
Hrs. on 10.09.2014.
Details of Failed CT:-
Make:- W.S. Industries.
Year of Manufacturing:- 1991.
Year of Installation at site:- 2007
Load Loss
Total Load Loss was approx. 68 MWH duration of outage was approx. 45 Minutes.
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Annexure - 2.15
On 01.10.2014 at 10:22Hrs, 220kV Y-ph CT of SCT make of 3 x 200MVA, 400/220kV ICT-4 burst
& Caught fire at 400kV Padghe s/s & ICT tripped on Differential Protection. The ICT-4 is connected to
220kV Main bus-1. The bursting of CT also damages the R & B ph CT of ICT-4. Due to fumes & flame of burnt CT,
it has created R –ph fault in the system at adjacent 220kV Jindal bay, due to which all
220kV lines & ICTs/TFs connected to 220kV Main bus-1 tripped. Subsequently it was observed that
the 315MVA, 400/220kV ICT-1 & 2 and 220kV Temghar line connected to 220kV Main bus-2 also tripped at 400kV
Padghe s/s. The remaining all 220kV lines & 200MVA ICTs/TFs connected to 220kV Main bus-2 are in service at
400kV Padghe s/s. Also 100kV lines & TFs are in service at 100kV Padghe s/s except tripping of 100kV Bhiwandi -1 &
2 which tripped on operation of load trimming schemes. The total load loss of 238 MW (excluding load shedding )
occurred for about 40-50 minutes.
Observations & Analysis: ( Pl refer the enclosed SLD , DR & Event List ):
Fault 1:-
On 01.10.2014, the 220kV Y-ph CT (make: SCT, Sr. No.2010/1063, YOM 2010, DOC 23.04.13) in respect of
3 x 200MVA, 400/220/33kV ICT-4 burst & caught fire. The ICT-4 is connected to 220kV Main bus-1 at
Padghe s/s.
The 220kV SCT make CT is commissioned on 23.04.13& given the service life of about 1 ½ Years. The
Capacitance & tan-d measurement of said CT is taken on dtd.29.06.2014 & the test result are as below.
Sr. No. Phase Capacitance (PF) Tan-d (%) Voltage (KV)
1 220kV _ R (SCT make) 285.13 0.28 10
2 220kV _ Y (SCT make) 265.85 0.47 10
3 220kV _ B (ITC make) 422.82 0.22 10
Further, it was observed that the CT Porcelain insulator found completely damaged and scattered which
damages the adjacent R & B phases CT. The CT top Dom remains suspended. The failure of CT is due to
Primary insulation failure.
This has created three phase fault in the system. This fault is in TF differential zoneof ICT 4
& cleared by differential protectionhowever, lately by about 300msec due to second harmonic blocking
condition on initiation of fault.
Here, anun-restrain High set of differential protection also fail to operate instantly (Areva, Micom P643) which
is being checked during outage.
Due to this delayed clearance of fault, simultaneously, the 220kV bus coupler also tripped on operation of
Back Up definite timeOC function (270 msec).
As such, the CT fault is isolated.
Fault 2 :-
After about 2 seconds, due to the fumes & flames, R –ph line fault is created on adjacent
220kV Jindal line bay which is cleared instantly from both ends with single R pole tripping. The 220kV
Jindal is connected to 220kV Main bus-1.
Fault 3 :-
After dead time of 1 sec, theA/R is operated for above fault at both Padghe & Jindal s/s, but line tripped
immediately on SOTF at Jindal end.
However, the CB of Jindal line remains closed at Padghe end. The DR shows that this time, no protection is
picked up at Padghe end & no current is seen by the CT confirming that the fault was remained before CT
between CB and CT i. e. Main Bus 1 Bus fault.
However, the BB protection (ABB RADSS) of 220KV Main Bus I found to be not operated for this nature of
fault which is being checked.
Then, the above R –ph system fault is sensed by distance relay of 220kV Temghar-1, Kamba,
Jambhul-1 in reverse zone (Zone-4) and HV B/U relay of 315MVA, 400/220kV ICT-3, LV B/U relay of
200MVA, 220/100kV ICT – 1 & 3.
Subsequently 220kV Temghar-1, Kambha lines tripped on R-E, Zone-4 at Padghe s/s and
220kV Jambhul-1 at remote end on B/U _ EF.
Also the 315MVA, 400/220kV ICT-3 & 200MVA, 220/100kV ICT – 1 & 3 tripped on B/U_OC
at Padghe end.
Thus, the fault in 220KV Main Bus – I is isolated.
The 220kV Temghar -2 connected on healthy bus – II also found to be tripped at Padghe end on B/U OC
which is simultaneously with the tripping of 220KV Temghar – I as it has act as bus section between Main Bus
I & II in event of tripping of Bus coupler at Padghe.
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Fault 4:-
With this, the complete load of Padghe s/s (radial load of about 885 MW) is shifted on 2 no. of 315MVA,
400/22kV ICT – 1 & 2 with support of 220KV Vasai (PGCIL) and 220KV Nasik feeders being source lines.
The 100KV line from Vasai and Kharbao- Kolshet are also remains connected with 100KV Padghe bus.
Then, load trimming scheme is operated at Padghe s/s due to sustained over loading on
400 kV ICT – I &II.
The load trimming scheme adopted at Padghe is as below.
1. Alarm is set at 90% of full load capacity of ICTs.
2. Stage-I is set to 100% with time delay of 1 sec to trip 100kV Bhiwandi – I & II at 100kV Padghe s/s.
3. Stage –II is set with time delay of 1 sec to trip 22kV feeders at 100kV Padghe s/s.
The quantum of Load relief obtained due to operation of load trimming is about 130MW.
Even after operation of load trimming scheme, the both 315MVA, 400/220kV ICT – 1 & 2 tripped on B/U _
OC as the over load is not sustained further.
Fault 5:-
Subsequent to the tripping of 400 kV ICT 1 & 2 , the total radial load of Padghe bus ( 755 MW ) was shifted on
remaining 220 kV source lines viz Vasai ( PGCIL) &Nashik with support from 100 kV Vasai &Kolshet bus on
100 KV Padghe bus.
However, this has resulted in to collapse of 220 kV Padghe Bus voltage to about
185 kV which remains for about 30 minutes till restoration of 400 kV ICTs. Under
such condition, the load relief is also resorted.
Restoration:
220 kV Main Bus I charged through bus coupler at 10:43 hrs. & Normalcy restored one by one as below:
Sr. Name of Bays Tripping Restoration
No. Date/Time Date/Time
1 220 KV Bus-Coupler 10:22 Hrs 10:43 Hrs
2 315MVA, 400/220/33kV ICT-3 10:22 Hrs 10:49 Hrs
3 3x200 MVA, 400/220/33 KV ICT-4 10:22 Hrs 20:00 Hrs
4 200 MVA 220/100 KV ICT-3 10:22 Hrs 11:04 Hrs
5 200 MVA 220/100 KV ICT-1 10:22 Hrs 11:08 Hrs
6 50 MVA, 220/22 KV T&R T/F 10:22 Hrs 10:43 Hrs
7 220 KV Jambhul 1 ckt 10:22 Hrs 11:25 Hrs
8 220 KV Jindal 10:22 Hrs 11:18 Hrs
9 220 KV KAMBA 10:22 Hrs 11:05 Hrs
10 220 KV Temghar-1 10:22 Hrs 20:06 Hrs
11 220 KV Nalasopara 10:22 Hrs 11:00 Hrs
12 315MVA, 400/220/33kV ICT-1 10:30 Hrs 10:48 Hrs
13 315MVA, 400/220/33kV ICT-2 10:30 Hrs 10:53 Hrs
14 400 KV Boisar 10:22 Hrs 11:17 Hrs
15 220 KV Temghar-2 10:22 Hrs 20:06 Hrs
Remedial Measures to be taken:
1. The all damaged 3nos of CTs of ICT – 4 is replaced by available SCT make CTs & ICT is taken back into service
at 20:00hrs.
2. The 220 kV Bus Bar Protection (ABB, RADSS) being checked for its performance.
3. The Transformer differential Protection (AREVA MICOM P 643) is being checked for its behavior during
occurrence.
4. The high content (51%) of second harmonic current during the fault conditions being studied.
5. The additional quantum of load is required to be incorporated in existing load trimming scheme to meet such
contingencies.
6. The old 220 kV Kalwa Nashik 3 &4 which was made LILO at Padghe earlier & then
removed from Padghe bus may please be explored to restored back for having availability of additional source
under such condition.
7. The manual load shedding should have been resorted at Padghe end by EHV line tripping immediately to maintain
the 400 kV ICT load under control & to prevent the prevailing low voltage condition of 220 kV Padghe bus.
8. The 220 kV Hybrid PASS Bus Sectionalizer is to be commissioned on priority.
9. The further observations/ study & checking follows.
Encl: As Above. The Chief Engineer (Tr. O&M), C.O.,
MSETCL, Mumbai. Kalwa.
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Annexure - 2.16
st
Grid Incidence at JP Nigrie and Satna on 1 October 2014
400 kV JP Nigrie station is connected with the Grid with 400 kV JP Nigrie-Satna D/C lines.
Previously on 17th September 2014 , It was observed that 400 kV JP Nigrie –Satna circuit 2 has
tripped on B Phase to earth fault causing tripping of its generating unit which was due to isolation of
JP Nigrie from the grid.
On 1st October 2014, At 10:34 Hrs 400 kV JP Nigrie-Satna 2 circuit develops transient R Phase to
earth fault due to vegetation which has resulted in three phase tripping of the line as Auto
Reclosure for the line was not in service. The fault current from Satna end was around 21 kA.
At the same time 400/220 kV ICT 1 from Satna tripped on IDMT overcurrent protection as
informed by CPCC Jabalpur. The tripping of the above ICT on through fault is still not understood.
Table 1 : Sequence of events
Event Analysis: 400 kV JP Nigrie - Satna 2 line has tripped on various instances which include 17th
September (B Phase to E/F), 30th September, 1st October and 14th October 2014 (R Phase to E/F). On
all these occasions fault was single phase fault due to vegetation issue in the ROW. JP Nigrie was
suggested for maintaining the proper clearances with the vegetation in ROW and adopting single
phase auto reclosure on the evacuation lines for better availability. In view of that outage has also
been given for vegetation clearance and A/R work in November. Now the Lines are not tripping and
it was confirmed by JP Nigrie that single phase A/R has also been taken in service for both circuits.
The tripping of 400/220 kV ICT 1 at Satna on IDMT O/C protection need to be checked by PGCIL for
its setting. If the fault current was too large then both ICTs should have tripped. PGCIL is requested
to kindly review the relay setting of ICTs at Satna.
Remarks:It can be observed that the root cause for the event were ROW Vegetation Management,
Non-availability of auto-reclosure and setting of ICT 1. PGCIL is requested to kindly check the setting
of ICT 1 at Satna.
~1~
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Annexure - 2.17
220 KV Pophali – Kandalgaon line was on TBC for maintenance work. At 19.10 Hrs. ‘R’ Ph. to Ground fault
occurred on above line and Distance protection operated at 220 KV Pophali end but due to non-tripping of TBC CB, LBB
protection operated. As a result all the lines and units connected to Bus section-I were tripped.
The details of Window & Relay indication at the time of occurrence is as given below:
Tripping Restoration
Sr. Window Generation
Name of feeder /TF Relay Indication Date & Date &
No. Indication Affected
Time Time
L. End- On Micom :P442
Active Group 1
Tripped Phase ABC
L. End-
Dist.. Trip Zone 1
1) Distance
Carrier received.
Prot. Optd.
220 KV Pophali - Dist: 74.8 Km. 03.10.2014 04.10.2014
1 2) LBB
220 KV Kandalgaon R. End- 19.10 00.37
operated.
Distance Protection Optd.
R. End-
Start Phase R-N
A/R Operated.
Zone 1, Carrier Received
Carrier Send
Distance 51.3 Km
03.10.2014 03.10.2014 20 MW
2 220 KV Bus Section 1 LBB operated
19.10 20.35
03.10.2014 03.10.2014
3 220 KV Pedambe 1 LBB operated
19.10 20.50
03.10.2014 03.10.2014
4 220 KV KDPH LBB operated
19.10 21.00
LBB operated 03.10.2014 03.10.2014
5 220 KV Unit 1 LBB operated
19.10 21.35
03.10.2014 03.10.2014
6 220 KV Unit 2 LBB operated
19.10 20.45
03.10.2014 03.10.2014
7 220 KV Unit 3 LBB operated
19.10 20.55
03.10.2014 03.10.2014
8 220 KV Unit 4 LBB operated
19.10 21.40
Analysis: At 220 KV Pophali S/Stn., 220 KV Kandalgaon Line was taken on TBC for carrying out the conductor
replacement work of Bus Isolator. At 19.10 hrs R Phase-Ground fault occur on this line so A/R operated at Kandalgaon end
and at 220 KV Pophali end distance protection operated. But TBC CB did not tripped so LBB protection operated at Pophali
S/Stn. So 220 KV Pedambe 1, KDPH, and Unit 1,2,3,4 was tripped on LBB protection. After checking the CB terminal box
of TBC, it was found that, tripping wire of TBC CB was loose. As A/R operated successfully at 220 KV Kandalgaon &
CB was in closed condition until it was H/T at 19.50 hrs.
Remedial Action: The Problem of TBC tripping ckt was rectified and line restored.
My Comp./E/TCC14/ Letters-14./Nov-14
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Occurrence of LBB protection operated at 220 KV Pophali S/Stn. on 03.10.2014 at 19.10 Hrs.
G1 G2 G3 G4 G5 G6 G7 0
G8
220 KV Pophali
Bus Section -I Bus Section -II
TBC
LBB operated
1Φ to E.Fault
220 KV KDPH
220 KV Pedambe I
Successful
A/R operation
220 KV Kandalgaon
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Annexure -2.18
To,
The Superintending Engineer (T&C)
MPPTCL Ujjain
63
Gmail
1 - Fwd: PT failure details at 220 KV S/s Badod
1 https://mail.google.com/mail/u/0/?ui=2&ik=b3d635e8bd&view=pt&q=chandan&qs=true&s...
ON 06.10.2014 AT 19:09 Hrs. Y-phase PT of 220 KV Badod Kota Ckt. burst at 220 KV S/s Badod creating bus fault and further resulting in
operation of Bus Bar Protection of 220 KV Main Bus - II at 220 KV S/s Badod. Consequently 220 KV Bus TIE and following 220 KV feeders/
transformers connected to 220 KV Main Bus - II tripped:-
due to above tripping there was no interruption in any area. DR & EL Files is enclosed.
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2 attachments
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Annexure - 2.19
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At 04:56 Hrs, the 220 kV B Phase CT (ITC make, COD: 18.05.2012) of 3 x 167 MVA, 400/220 kV ICT 3 burst and
caught fire at 400/220 kV Kalwa Sub-station. The differential protection of said ICT operated correctly and tripped the HV
and LV side circuit breakers. The CT failure has created the Bus fault on 220 kV Bus 2 on which the ICT-3 was connected.
The 220KV Bus bar Main Zone 2 protection (Type REB 670, ABB make) operated simultaneously at Kalwa sub-
station. This has resulted into the tripping of all 220 kV lines / ICTs connected to 220 kV Main bus 2 along with 220 kV
Bus Coupler and the Interconnector CB. The 3x167MVA, 400/220KV ICT – 3 is connected to 220KV Main Bus – II at
Kalwa s/s. The operation of bus bar protection was in order.
Further it was observed that the CT porcelain was completely damaged and scattered which damaged the Line and
Transfer Bus isolator support insulators. In addition, the CT cables of R, Y, and B phases were found burned and damaged.
The failure of CT is due to primary insulation failure.
Due to the fumes and fire, R phase fault got created on adjacent 220 kV Kalwa-Mulund 2 bay which was cleared from
Mulund end on backup O/C protection operation. However, at Kalwa end, the CB has already tripped on Bus bar protection
operation.
The 220 kV Borivali line which was connected 220 kV Main Bus 1 at Kalwa station also tripped during the event on
operation of distance protection for B Phase to earth fault in Zone 1 from 220 kV Borivali end.
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Event Analysis:
The event was analysed based on the available PMUs data and MSETCL report.
It can be observed in the Voltage plot of Kalwa PMUs from figure 3 that Initial fault, which developed, has resulted in
R-B Phase dip. Later a second fault occurred in the system after 2 seconds of the first fault.
To classify the fault type, the PMUs plot of Kalwa-Padghe 2 and Kalwa –Khargar line current from PMUs shown in
figure 4 and 5 respectively were used. It can be observed that First fault has fault current in B Phase only indicating B
phase fault. While second fault has maximum fault current in R phase indicating the nature of fault to be in R Phase. The
same has been confirmed based on the MSETCL report.
It can be observed the Bus fault due to B Phase CT burst has got cleared within the 100 ms. However, at the same
time The 220 kV Borivali line which was connected 220 kV Main Bus 1 at Kalwa station also tripped on distance
protection in Zone 1 from 220 kV Borivali end. The distance relay is seems to be overreach for CT failure fault at Kalwa.
MSETCL is requested to look into the setting of the relay and need for any change.
Due to the fumes and fire, second fault that is R phase fault got created on adjacent 220 kV Kalwa-Mulund 2 bay
which was cleared from Mulund end on backup O/C protection operation. The time duration for clearance of this fault is
around 360 ms. Such faults could not have been fed to the system if the direct trip would have gone to the remote end
station after the bus bar protection operation. MSETCL is requested to check for facilitating the direct trip command
as done for 400 kV and above system. This will help in containing the fault during the CT/PT burst.
The change in frequency during the event was 0.0269 Hz indicating a load loss in tune of 160 MW. MSETCL report
did not indicate any load loss. Maharashtra SLDC is requested to have a look into all such events and confirm the
Load/generation loss along with Energy unserved during such events.
Remarks: MSETCL is requested to have a look into the increasing number of CT failure in the system. In addition, it is
advised to test all the CT/PT after any bus fault at the station or nearby station. It may be observed that on 1st October 2014
a severe three phase bus fault occurred at Padghe which may be a probable reason for CT failure in this case.
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96T BC
220KV Main Bus - II 52A 52C
T ,87,
96T 96T 96T 96T 96T 96T 96T
400KV 220KV
B ph CT Kalwa -I Kalwa -II
burst
&
4 6 3
caught fire
3x167MVA
400/220KV 3x167MVA 3x200MVA
ICT - 3 400/220KV
2 1 400/220KV ICT - 2
ICT - 1
T, 87,
96T
96T 220KV
Salsette
220KV
Bapgaon T, B/U ,
O/C
220KV
R ph 220KV 220KV Tifil Colourchem
Siemens
220KV
Mulund
T, B-E,
Z1
220KV
220KV Padghe
Nasik
Figure 2 : SLD of the Sub-Station indicating the fault and operation of various Relay (Source: MSETCL Report)
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Annexure - 2.21
Grid Incidence at 765/400 kV Raipur Pooling (Durg) Sub-Station on 13th October 2014
Event Summary: At 11:37 Hrs, R-Y phase-to-phase fault occurred on the 400 kV Raipur-Raipur (PS) circuit 2.
The distance protection of line operated at both end and line got isolated from Raipur while due to stuck
breaker problem of Main Circuit breaker of line at Raipur (PS) , it LBB operated. This has resulted in tripping
of all main and tie CB of 400 kV Bus 1 at 765/400 kV Raipur Polling station.
Event Overview: Prior to the event, all the lines and elements from 400 kV Raipur Pooling station were in
service. The Hud Hud cyclone has moved to the Chhattisgarh area and warning notice from WRLDC/NLDC
have already been issued to the constituents by NLDC. Operator at every control center were in alert
mode and very keen monitoring of system was underway at each control center so that any event in the
system can be detection as early as possible faster restoration can be done based on accelerated analysis of
the event. Rains and heavy wind were prevailing near Raipur area.
At 11:37 Hrs : WRLDC/NLDC operator have observed the dip in the Bus voltage measured from the
Raipur PMU. Along with that, high df/dt was also observed at Raipur and Bhadrawati PMUs in the
display at WRLDC/NLDC. WRLDC operators after analyzing the SCADA display observed that 400 kV
Raipur-Raipur (PS) line 2 breakers has opened and simultaneously 400 kV Bus 1 voltage of Raipur PS (Durg)
sub-station was zero.
Based on the voltage observed from the PMU as shown in figure 2, it was observed that R-Y Phase to
Phase fault has occurred in the system and it took around 560 ms to clear the fault.
WRLDC had then called CPCC Nagpur for the incident but CPCC was not aware about the event. It
took a lot of time from CPCC to confirm the event from Raipur and Raipur Pooling station. CPCC then
informed only about the tripping of 400 kV Raipur-Raipur (PS) circuit 2 while the 400 kV Bus 1 tripping was
not informed to them from sub-station. In addition, it was informed that fault location from Raipur end
was 1 km.
Further analysis was done at WRLDC Operators based on available input from PMU and site and it was
concluded that R-Y Phase to phase fault has occurred on the 400 kV Raipur-Raipur
(PS) circuit 2 and it was in zone 1 from Raipur while in Zone 2 from Raipur Pooling station. Raipur end has
correctly tripped the line in Zone 1 within 100 ms while Raipur PS has tripped in zone after 300ms. It was
thought that due to PLCC problem, the fault from Raipur PS might not have been cleared in zone 2.
When the breaker got tripping command from relay at Raipur PS, the tie CB got opened while the Main CB
got stuck which initiated the LBB protection for the Main CB of the circuit. So, after 200 ms (LBB Operation
time) all main and Tie CB of 400 kV Bus 1 at Raipur PS tripped to isolate the fault.
So fault clearance time based on protections setting: 300 ms (for zone 2 operation at Raipur PS + 200 ms
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LBB operation at Raipur = 500ms. The same has matched with the PMU data and SCADA CB opening status
and SOE.
WRLDC Informed CPCC about the above analysis and informed them to open the isolator at Raipur for
the fault breaker and isolate the faulty breaker from system and ask for charging code for 400 kV Bus 1 so
that system can be strengthen.
Looking at Phase to phase fault, CPCC Nagpur was asked to patrol the line.
It was observed that even after the situational awareness at NLDC/WRLDC/CPCC, operator at Raipur
pooling station has charged the 400 kV Bus 1 at 12:33 Hrs without any intimation to WRLDC and has not
taken any code.
Later on patrolling of the line, it was found that at Location no. 59, Y phase (Middle) Jumper has
snapped which has created the fault. Fault rectification work of said line could not be completed due to
heavy rainfall on 13th October and was done on the next day. The line was restored after completion of
work at 13:25 Hrs on 14th October 2014.
Table 1 : Sequence of events
Elements Tripping Relay Indication at Relay indication Restoration
Time End 1 at End 2 Time
Zone 2, DPR
Zone 1, DPR operated, R-Y
operated, R-Y phase- Phase to phase
to-phase fault, fault, Carrier
13:25 Hrs
400 kV Raipur-Raipur(PS) 2 11:37 Carrier send to not received.
14-10-2014
remote end. Carrier LBB operated
not received. for R-Y Phase
for Main CB
400 kV bus 1 at Raipur PS 11:37 LBB Operated, R-Y Phase 12:33
* Based on WRLDC SCADA SOE/PMU
Event Analysis
DR of the circuit from Raipur and Raipur PS were analyzed and their summary is given below:
Raipur End: it is observed that fault has initiated at 11:37:50.757 (in PMU 11:37:50.720)
and Zone 1 protection operated at Raipur end. Fault fed from Raipur for the fault through the circuit was
as following IR= 40.8 kA, IY=40.8 kA, IB= 0.35 kA. In the next 72 second fault got cleared from the Raipur
end. Carrier was send from the Raipur PS but no carrier has been received from remote end.
Raipur Pooling station (Durg): Fault was in zone 2 from Raipur PS and no carrier was
received from Raipur end so zone 1 carrier aided protection did not operate and DPR operated as per zone
2. Initially fault current were IR=4.39 kA, IY= 4.39 kA, IB=0.31 kA. After around 70 ms, when fault was
cleared from remote end (Raipur end), fault current from Raipur PS has increased to IR=13.1 kA, IY=13 kA,
IB=0.02 kA. After 384 ms zone 2 protection operated. It was observed that Tie CB has opened while Main
CB R-Y has not opened. It was also found that now the ground current has also started to flow through
the neutral, which is due to arcing in the circuit breaker IR= 13 kA, IY=12.7 kA, IB=0.016 KA, In=9.8 kA.
The LBB operated in the next 189 ms. The total fault time observed was around 581 ms (from PMU 560
ms).
The LBB for main CB has operated causing tripping of 400 kV Main Bus 1 and all associated
breakers at Raipur PS.
Remarks: WR-1 and Chhattisgarh Project RHQ of PGCIL is requested to kindly coordinate in the
integrated operation of the grid and provide all possible information in real time for reliable
operation of the grid.
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Annexure - 2.22
Grid Incidence at 765/400 kV Solapur (PG) Sub-station resulting in loss of Synchronization between
NEW and SR Grid on 16th October 2014
Event Summary: Due to Human Error, both 765/400 kV ICTs at 765/400 kV were hand tripped by the
operator at Solapur Sub-station while availing outage on one of the ICT. This has resulted in loss of
synchronization between NEW and SR grid.
Event Overview:
Emergency Outage was approved for the 765/400 kV ICT 2 by the NLDC/WRLDC
for attending diverter switch problem in OLTS as winding resistance tap position 18, 20 and 22 were found to
be in open condition. WRLDC issued the code for the outage of the ICT 2 to CPCC Nagpur and it was
conveyed to Operator at Solapur Sub-station for initiating the work.
Immediately Solapur Control room was enquired about the operation and it was confirmed
that the human error has resulted into the issue.
Table 1 : Breaker status during loss of synchronisation
Breaker Time Status
703 13:12:49.513 Open
423 13:13:04.017 Open
422 13:13:04.020 Open
703 13:13:25.667 Closed
706 13:14:00.469 Open
428 13:14:47.342 Open
705 13:14:47.377 Open
Restoration: After analyzing the event from various data (SCADA, PMU and information from Sub-
station), It was confirmed that there was no fault in the system and tripping has occurred due to Human
Error, Immediately restoration activity were started.
The single line diagram after the tripping is shown in figure 3.
Looking at the scenario of breaker at 400 kV and 765 kV level, It was thought to first
synchronize the NEW and SR grid across the 400 kV Breakers i.e. 422 or 423. This was not agreed by the
Solpaur Control room without providing any reason.
So it was planned to synchronize the grid at 765 kV level so, the breaker of ICT 1 at 765 kV
level need to be opened (CB No 702 and 703) and 400 kV breaker to be closed first and synchronize the grid
across either 702 or 703 breaker of ICT 1. This was also not agreed by the sub-station as there were two
problems at that time :
1. The Breaker 704 was having CSD issue as explained earlier so was not opening. (This was not informed
to WRLDC/NLDC during real time)
2. Specific parameters were not entered for auto synchronizing facility across these
breakers at in the station, which is having Substation automation system (Here there is no conventional
synchro check trolley for closing the breakers because the SAS system has auto synchronization facility at the
Bay control unit (BCU). Operator at sub-station control room to look into the synchronization from the auto
synch features at any SAS uses digital synchrocheck relay display). The sub-station operator was
reluctant for configuring the parameters in these breakers.
Then it was informed that the auto synchronizing facility to synchronize the NEW and SR grid is only
avavaible across the breaker of 765 kV Solapur-Raichur 1 and 2 circuit which 713, 714, 715 and 716.
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Then it was decided to isolate the 765 kV Bus 1 and Bus 2 by opening of the all the Tie CBs thus
isolating CUT 1 on one bus and 765 kV Solapur-Raichur 1 & 2 on other Bus. After this synchronizing the grid by
taking ICT 1 by charging its 400 kV side breakers and then closing the Tie CB of either of the 765 kV Raichur-
Solapur circuit ( i.e. CB 714 or 716 ). But it was also not agreed in view of the following :
1. The Breaker 704 was having CSD issue as explained earlier so was not opening. (This was not known to
WRLDC/NLDC during real time)
2. Synchronization of grid through tie bay should have resulted in total power flow through tiebreaker,
which may result in unintentional protection operation. Although this should not have been a problem
as during synchronisation, power flow is less across the line.
After this operator at NLDC and WRLDC along with CPCC Nagpur and Solapur S/s discussed the
issue and it was observed that operator at Solapur was not ready for synchronization across other breaker by
inputting the synchronization parameters. In view of this it was thought to synchronize the system using the
process as followed earlier on various synchronization i.e. to open the 765 kV lines from Solapur end and then
close the ICT 1 from 400 kV end followed by closing of 765 kV Line breaker.
The above sequence started by opening the 765 kV Solapur-Raichur lines Breakers (Main and Tie) at
Solapur end. This was done first by blocking the direct trip from Solapur end to ensure line should not trip
from remote end on DT command. This resulted in dead 765 kV Buses at Solapur. After this 400 kV Circuit
breaker of ICT 1 were closed and 765 kV Bus 2 was charged. The synchronization was then done after closing
of the Tie CB 716 through 765 kV Solapur-Raichur 1 circuit. The restoration of various circuit breaker is shown
in table 2.
Table 2 : Restoration sequence of Breaker
Breaker Time Status
713 14:56:15.256 Open
714 14:56:25.492 Open
716 14:56:46.209 Open
717 14:56:54.773 Open
422 15:02:40.831 Closed
423 15:02:49.154 Closed
716 15:38:16.413 Closed
717 15:39:00.974 Closed
713 15:44:23.236 Closed
714 15:44:57.565 Closed
Table 3 : Sequence of events
Elements Tripping Relay Indication Relay indication Restoration
Time at End 1 at End 2 Time
Tie Breaker
765/400 kV 1500 MVA Solapur ICT 1 13:13:04.017 Intertrip 15:02:49.154
remained closed
765/400 kV 1500 MVA Solapur ICT 2 13:14:47.342 Hand Tripped Intertrip
Remained
765 kV Solapur Raichur 1 14:56:54.773 Hand tripped 15:38:16.413
Charged
Remained
765 kV Solapur Raichur 2 14:56:25.492 Hand tripped 15:44:23.236
Charged
Event Analysis and various lessons learnt during the event
The incident was a result of human error and lessons need to be drawn so that in future such event could be
prevented. These lessons can be summarized as following:
765/400/220 kV Solapur Sub-station is one of the very important sub-station in view that the NEW
and SR grid are synchrosed through the 765 kV Solapur Raichur D/C. So skilled manpower is the very
essentiality for this sub-station.
The event could have been avoided if the operator would have:
1. Seen the SAS display indicating only reactive power in the ICT 1 as 400 kV side breaker were in open
position.
2. Seen the 400 kV Breaker of ICT 1 on the SAS display
3. Seen the Event logger in the sub-station SCADA indicating the breaker status of ICT
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4. Seen that no real power flow has started through ICT even after closing of the 703
5. Consulted other person in the shift and informed the CPCC Nagpur or WRLDC about the incident when
human error has occurred.
This suggest that manpower at such station should be very skilled and trained so that during such error he could
avoid further oversight into the event and take a corrective action after informing others.
One most important issues that was observed during the event was Sub-station operator confidence
in synchronizing the grid through other breakers by configuring the auto synch feature of the breaker. Enough
trained manpower need to be present in such important sub- station from where NEW and SR grid are
synchronized and has a significant impact on the whole Indian grid during any event. The non-availability of
trained operator in SAS operation of Solapur has resulted in delay in restoration of the system because of operator
inability to configure the parameters in auto synch relay. The issue was further analyzed and points are presented
as following :
1. In a Manual control station without having SAS, the synchronization will be done through conventional
synchrocheck relay trolley. Hence, synchronization can be done across any breaker where VT output is
available in the control room. In such relay operator don't have to put the value of various criteria for measured
values as its in manual mode and operator by just looking at various dials or seven segment LED display close
the breaker.
2. While in case of SAS sub-station like Solapur, the setting has to be kept save across the planned breaker
for which operator have to do the synchronization in the system. So for synchronising across other breaker,
Operator have to put the various parameter prescribed for synchronisation and for that operator need to trained.
This will be a major challenge during emergency condition like blackout as in such time for faster restoration
of system; RLDCs/NLDC Operator will desire to have synchronization across any breaker, which is first
available. For the same operator at the sub-station has to input the parameters prescribed for successful closing of
two islands and for that operator need to be well prepared in advance.
Another observation during the event was found that auto synchronisation display through digital
synchrochek relay is not available at operator desk in the Sub-station for all the breakers. It is avavaible only for
the selected breaker for which planned synchronisation is being done. For any other breaker, its non-availability
will reduce the operator confidence while synchronising the islands across that breaker.
The non-opening of Tie Breaker due to CSD problem need to be further analysed in details as
this may have caused a damage to the ICT in case of any fire as operator would not have
been able to isolate the ICT without tripping of the 765 kV Bus 1. PGCIL WR-1 is requested to prepare a
report on the same and submit to WRLDC/WRPC.
Remarks:
Therefore, the above incident has provided many inputs and lessons to all the operators in the Indian grid.
These lessons will help in training of the operator for handling such emergencies effectively. It provides the input
that operator at sub-station should be very well versed with the situational awareness tool provided and should not
act in hurry during any human error.
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Annexure - 2.23
Sub: Report on grid disturbance occurred in Gujarat system on 19.10.14 at 21:03 Hrs.
On 19/1014 at 21:03 Hrs, grid disturbance occurred in Gujarat Power System. It led to generation
loss of around 475 MW at SLPP.
Page 1 of 4
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At 21:03 Hrs, R phase EMVT of 220 KV bus-A of Stage – 1 failed. As a result, bus-A (R-Y phase)
under voltage and bus-bar differential check-zone relay operated; but, at the same time, main
zone – A differential relay failed to operate resulting into tripping of GT-1, GT-2, ST-1, ST-2, Bus
coupler, interconnection breaker-A on back up earth fault relay operation and tripping of GT - 3 &
GT -4 on back up impedance fault. At the same time, 220 KV Gavasad – SLPP line No. 1 tripped
on Z-1 protection. 220 KV Gavasad – SLPP line No. 2 & 4 tripped from Gavasad end on Z-2
protection. The 220 KV SLPP – Zaghadia line No, 1 & 2 tripped from Zaghadia end on Z-3
protection. The 220 KV SLPP - Karjan line breaker at Karjan end did not trip; but, the bus coupler
breaker of Karjan substation tripped on LLB protection.
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7. Sequence of restoration:
During thorough checking, the Phase-1 220 KV Bus-A, R-phase PT was found damaged.
After isolating 220 KV Bus-A of phase – 1, the rest of system was normalized.
At 21:25 Hrs, 220 KV SLPP – Karjan line was charged from Karjan end and it was
taken on 220 KV Bus - B of Stage-1 at SLPP on 21:56 Hrs.
At 21:40 Hrs, 220 KV SLPP – Gavasad line No. 2 was taken into service and Stage – 2
switchyard was charged.
At 22:03 Hrs, 220 KV SLPP – Zaghadia line No. 1 was taken in service on 220 KV Bus
– B of Stage – 1 at SLPP.
Both the station transformers at SLPP were charged at 22:11 Hrs.
On 20.10.14 at 01:05 Hrs, 220 KV SLPP - Gavasad line No. 1 was taken into service.
On 20.10.14 at 02:22 Hrs, 220 KV SLPP - Zaghadia line No. 2 was taken into service.
8. Remedial measures to be taken to avoid recurrence:
Thanking you,
Yours faithfully,
Sd/-
(B. B. Mehta)
Chief Engineer (SLDC)
Page 3 of 4
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Annexure - 2.24
Detailed report on the occurrence at 220 kV Uran Gas Power S/s in Maharashtra on 23rd October 2014
5. Event Overview:
Prior to event, system was in normal operating condition. All 220 kV lines were in service from Uran sub-
station.
At 08:35:40 Hrs : B Phase Pole of 22 kV side circuit breaker (Siemens VCB make) of 220/22 kV 50 MVA ICT
2 burst and caught fire along with flashover/fire underneath the Local control cubicle of circuit breaker at 220 kV
Uran station.
This has initially created bus fault (B phase earth) on 22 kV side which is subsequently converted into three
phase to earth fault. This fault was a through fault for the ICT which should have been cleared by the H/V side
backup protection which did operate.
The 22 kV side 3 phase through fault of ICT with fault current of magnitude of about 8000 Ampere was
sustained by Transformer for prolonged period as this 22 kV LV side ICT fault has not been sensed by any 220 kV
lines from their remote end protection scheme and generating Unit of Uran by their protection scheme connected on
220 kV Bus.
However simultaneously (After about 39 msec after 22 kV CB fault), the 220 kV Uran-Kharghar 1 and 220 kV
Uran-Apta -1, 3, 4 lines circuit breaker were found to be tripped from Uran end only due to DC grounding/leakage
developed due to problem in DC source.
The 22 kV ICT LV side three phase fault has not created any major disturbance on 220 kV system so that it can
be sensed by protection scheme except some minor distributed unbalance in voltage and current on 220 kV side.
Therefore long duration hanging three phase through fault on ICT LV side has led to development of internal fault
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inside the ICT. This internal fault was also not detected and cleared instantly due to failure of associated switchgear
and unit protection scheme of the ICT resulting failure and fire in the ICT.
This has led to high fault current from H/V side of the ICT being fed to internal fault of ICT which was sensed by the
220 kV GT protection and line protection. The two source feeder which were remaining (four lines already tripped o
n DC leakage) i.e. 220 kV Uran-Apta 1 and 220 kV Uran-Khargar 2 tripped from remote end. While the Units at Ur
an have tripped on various protection scheme.
This led to complete loss of supply at 220/22 kV Uran sub-station.
Table 1 : The details of tripping and restoration
Time of
Name of the transmission Time of TrippingRelay indication
Sl No. Relay Indication End restoration
2
element / Unit (hh:mm) End 1
(hh:mm)
1 220 kV Uran-HOC-Apta 1 08:35:46.652 Nil Nil 11.38
DPR Optd,
R, Y, B, Zone-1, Fault
location = 19.64 km
2 220 kV Uran-Apta 2 09:36:41.201 Nil Fault Current IR = 1.475
11.24
kA
IY = 6.863 kA
IB = 2.105 kA
3 220 kV Uran -Apta 3 08:35:46.652 Nil Nil 19.20
10.43
08:35:46.652
4 220 kV Uran-Apta 4 Nil Nil (220 kV Bus 1
Charged)
5 220 kV Uran-Khargar 1 08:35:46.652 Nil Nil 10.50
B/U O/C
R, Y trip 14.31 (220
Dist Prot. Relay, Fault Current kV Bus 2
6 220 kV Uran-Khargar 2 08:36:41.440
R, Y Phase IR = 7.040 kA Charged)
IY= 7.520 kA
IB= 2.880 kA
7 220 kV Uran-ONGC 08:37 Hand Tripped Nil 11.02
8 220 kV Uran-JNPT 08:37 Hand Tripped Nil 10.55
9 220/22 kV 50 MVA ICT 1 08:37 Hand Tripped Nil 12.50
10 220/22 kV 50 MVA ICT 2 08:37 Hand Tripped Nil -
11 GT Unit -6 08:37:44.018 Boiler protection optd. Turbine trip 17.00
25-10-14
12 GT Unit -7 08:37:11.300 Turbine trip
15:43
13 GT Unit -8 08:37:36.880 Imped. protection trip 13.04
14 GT WHRO Unit –A0 08:37:38.340 Over frequency trip 20.16
15 GT WHRO Unit –B0 08:37:39.940 Over frequency trip 24-10-14 14.33
16 220 kV Bus- Coupler 08:38 Hand Tripped 14.51
17 GT Unit 5 Out - 14.17
*As per data provided in MSETCL Report, time alignment of Event logger data of Uran using Khargar 2 relay and
PMU data.
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Time Event
08:35:45.307 Normal load current in ICT-2
22 kV B Phase pole of 220/22 kV 50 MVA ICT-2 burst and caught fire.
First Fault
08:35:45.412
1. B Phase fault started and current in other two phases i.e. R & Y were normal load Current.
2. DC grounding & TF protection failed to operate.
08:35:45.435 Bus Bar relay gave the Zone 1 alarm in the through fault.
ICT -2 R, Y & B phase currents increases to about 800 Amp on H/V side as the single phase on 22
08:35:46.652
kV side has got converted to three phase fault..
220 kV Uran-Kharghar 1 and 220 kV Uran-Apta -1, 3, 4 lines circuit breaker tripped from Uran
08:36:26.862
end due to DC grounding
Second Fault
08:36:41.100
ICT-2 R and Y Phase current increased abruptly on 220 kV side indicating HV Fault.
09:36:41.201 220 kV Uran-Apta 2 tripped in Zone-1 at Apta end.
08:36:41.440 220 kV Uran-Kharghar 2 tripped at both end on line protection.
08:37:11.300 GT -7 tripped.
08:37:36.880 GT – 8 tripped.
08:37:38.340 GT – A0 tripped.
08:37:39.940 GT – B0 tripped.
08:37:44.018 GT – 6 tripped.
*As per data provided in MSETCL Report, time alignment of Event logger data of Uran using Khargar 2 relay and
PMU data. Timing prior to second fault is not perfectly time synchronized w.r.t. PMU data.
Load / Generation affected: Total generation loss was around 458 MW while load loss was 34 MW.
Restoration: System restoration started after isolating the faulty equipment from system and ensuring remaining
equipment were healthy. The 220 kV Main Bus 1 charged through 220 kV Uran-Apta 4 at 10.43 Hrs. After this
other lines and local loads were restored one by one. Unit 8 was taken at 13:04 Hrs and Unit 5 which was out was
taken in service at 14:17 Hrs. Subsequently other units were taken back in service as per the schedule.
6. Event Analysis: So it can be observed from the overview of the event at Uran, that a series of failures of
equipment and protection were involved. The analysis presented here are the extract of MSETCL report combined
with the PMU/DR/EL data.
Fault at Uran 220 kV can be visualised as two separate faults i.e. First Fault and Second fault
First Fault i.e. LV side Breaker pole failure : At 08:35:40 Hrs, B Phase Pole of 22 kV side circuit breaker
(Siemens VCB make) of 220/22 kV 50 MVA ICT 2 burst and caught fire along with flashover/fire underneath the
Local control cubicle of circuit breaker at 220 kV Uran station. This can be visualized in the PMU voltage of Kalwa
where small fluctuation were observed. The exact time could not be matched with the event logger of MSETCL.
This has initially created bus fault (B phase to earth fault) on 22 kV side which has subsequently converted into three
Phase to Earth fault. This fault was a through fault for ICT 2 and should be cleared by H/v side backup overcurrent
protection. However the fault was not cleared due to non-operation of the protection. MSETCL has analyzed the
reasons and extract from report are given below :
The flashover, bursting and burning of LV breaker galloped the underneath operating cubicle which burnt &
damaged all the control cables so badly as if the High Voltage is entered into Control DC/AC supply .
Due to such abnormal High Voltage phenomenon ,
Power card of HV B/U CSC Relay got badly damaged
Power card and IP/OP Card of Numerical Differential ER make Duo Bias relay was badly damaged. It was
also observed that some Transformer Aux. B/I has also picked up which was due to damage of IP/OP card.
WRLDC, Mumbai Page | 3
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Annexure - 2.25
Grid Incidence at 400/220 kV Chandrapur TPS in Maharashtra on 23rd October 2014.
Event Category: GI-2
Event Date and Time: 23rd October 2014, 02:39 Hrs
Event Summary: At 02:39 Hrs, Bus bar protection of 400 kV Bus 2 operated at Chandrapur station which has
resulted in tripping of lines/ICT/Unit connected from the bus along with the Bus coupler. The Incident has
resulted in loss of 564 MW generation at Chandrapur TPS.
Event Overview:
Prior to the event, all 400 kV Elements from Chandrapur station were in service.
At 02:39 Hrs, Due to fire in the HP/LP control of Unit 2 on the GCR side, DC control cables caught fire
which resulted in the shorting of LBB wires. This has led to the operation of LBB protection for Unit 2
resulting in tripping of all elements connected on 400 kV Bus 2 at Chandrapur station.
This has led to tripping of Unit 4 and 6 along with Unit 2 at Chandrapur resulting in loss of 564 MW
generation.
Frequency has dropped by 0.093 Hz due to loss of generation. The calculated power number of Indian
grid during the tripping was 6064 MW/Hz.
Table 1 : Sequence of events
Elements Tripping Relay Indication at Relay indication at Restoration
Time End 1 End 2 Time
400 kV Bus Coupler 02:39 LBB operation N/A
GT 2 02:39 LBB operation - N/A
GT 4 02:39 LBB operation - 08:13
GT 6 02:39 LBB operation - 07:06
400 kV Station T/F 3 02:39 LBB operation N/A
400 kV Station T/F 5 02:39 LBB operation N/A
400 kV Chandrapur- 02:39
LBB operation DT 04:18
Chandrapur2 2
400 kV Chandrapur-Parli 02:39 LBB operation DT 04:11
400 kV Chandrapur 02:39
LBB operation DT 04:56
Bhadrawati 2
400 kV Chandrapur 02:39
LBB operation DT 04:51
Bhadrawati 4
400 kV HVDC I/C 1 02:39 LBB operation - 04:07
400/220 kV 315 MVA ICT 1 02:39 LBB operation 04:29
* Based on MSETCL Report
Figure 1 : 400 kV SLD of Chandrapur Station after the event ( Source : MSETCL)
~1~
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Annexure - 2.26
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Annexure - 2.27
Pre-Fault Condition: On dated 30.10.14 at around 17:45 Hrs MP System was normal and
frequency of National Grid was 49.75 Hz.
220 KV Rewa – Tons Ckt – I & II were under shut down since 28.10.2014 for increasing the height
of tower for crossing over of Highway. At 220 KV S/s Rewa, remaining 220 KV & 132 KV feeders
were in charged condition and normally loaded. At 220 KV S/s Rewa Single Main Transfer (SMT)
Bus scheme exists.
Occurrence: At 17:52 Hrs, suspension disc between Circuit Breaker 220 KV Rewa – Sidhi line
and 220 KV Main Bus Isolator at 220 KV Rewa failed, causing the bus fault at 220 KV S/s Rewa and
resulted in operation of 220 KV Bus Bar Protection at 220 KV S/s Rewa. Consequently following
feeders and X’mer tripped:-
1. 220 KV Rewa – Sidhi Ckt.
2. 220 KV Rewa- Satna Ckt.
3. 220/132 KV, 160 MVA X’mer – I & II at 220 KV S/s Rewa.
4. 132 KV Sidhi – Rewa Ckt.
5. 132 KV Satna – Rampur Baghelan Ckt. (from 220 KV S/s Satna due to over loading).
6. 132 Rewa II(Sagra) – Sidhi Ckt. (from 220 KV S/s Sidhi due to over loading).
7. 132 KV Maihar – Amarpatan Ckt. (due to over loading).
Remaining 132kV feeders & 132/33 kV X’mers at 220 KV S/s Rewa were hand tripped at 17:55 Hrs.
Remedial Measures
Supply at 132 KV S/s Rampur Baghelan was resumed by charging 132 KV Satna – Rampur
Baghelan Ckt at 18:10 Hrs. Further 132 KV supply was extended to 132 KV S/s Rewa by charging
132 KV Rampur Baghelan – Rewa Ckt at 18:10 Hrs. Supply at 132 KV S/s Rewa II (Sagra) was
resumed at 18:27 Hrs. by charging 132 KV Rewa II (Sagra) – Sidhi Ckt.
132 KV supply at 220 KV S/s Rewa was resumed by charging 132 KV Interconnector – I at 18:36
Hrs. subsequently following feeders and transformers were charged:-
Time in Hrs.
S.No. Name Of Feeder/Transformer
Tripping Charging
1. 132/33 KV, 40 MVA (NGEF) X’mer – I at 220 KV S/s Rewa. 17:52 18:42
2. 132 KV Rewa – Rewa II (Sagra) Ckt. 17:52 18:46
3. 220 KV Rewa – Satna Ckt. 17:52 19:22
4. 220/132 kV,160 MVA(CGL) X’mer–I at 220 kV S/s Rewa 17:52 19:25
5. 220/132 kV,160 MVA(BHEL) X’mer–II at220 kV S/s Rewa. 17:52 19:28
6. 132 KV Rewa – Mangawan Ckt. 17:52 19:35
7. 132 KV Katra – Mangawan Ckt. 17:52 19:35
8. 132 KV Rewa – Silpara Ckt – I 17:52 19:36
9. 132 KV Rewa – Rampur Niken Ckt. 17:52 19:38
10 132 KV Beohari – Rampur Niken Ckt. 17:52 19:38
11. 132/33 KV, 40 MVA (EMCO) X’mer – II 17:52 19:40
12. 132 KV Rewa – Jhinna Ckt. 17:52 19:41
13. 132 KV Rewa – Silpara Ckt – II. 17:52 19:42
14. 132 KV Rewa – JP Cement (Baghawar) Ckt. 17:52 19:43
15. 132 KV Interconnector – II. 17:52 19:47
Conclusion: The tripping occurred due to failure of suspension disc between circuit breaker 220
KV Rewa – Sidhi line and 220 KV Main Bus Isolator at 220 KV S/s Rewa.
220 KV Rewa – Sidhi Ckt was charged at 20:11 Hrs. through Bus Coupler breaker. Its ‘Y’-Phase
cable for supply to breaker coil was also found damaged in addition to suspension disc failure at 220
KV S/s Rewa. On 01.11.2014 after replacing the ‘Y’-Phase cable for breaker supply and the
suspension disc between 220 KV Rewa – Sidhi line Circuit Breaker and 220 KV Main Bus Isolator at
220 KV S/s Rewa, 220 KV Rewa – Sidhi Ckt was charged through its main breaker at 09:40 Hrs.
Load Loss:Total Load Loss was approx. 141 MWH & for approx. 1Hour 34 Minutes.
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Annexure - 2.28
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Annexure - 2.29
COMMENTS OF SLDC
Pre-Fault Condition: On dated 11.11.2014 at around 20:50 Hrs. M.P system was normal and frequency was 50.12 Hz.
At Omkareshwar HPS, all feeders were in charged condition and normally loaded and at Omkareshwar Power Station
(OSP) all Units were in OFF condition.
Occurrence: On dt. 11.11.2014, at 20:56 Hrs. all lines emanating from OSP HPS i.e., 220 KV Omkareshwar – Nimrani (Tap
Barwaha), 220 KV Omkareshwar – Barwaha, 220 KV Omkareshwar – Julwania, 220 KV Omkareshwar – Chhegaon and 220 KV
Omkareshwar – Khandwa tripped tripped on over voltage resulting in interruption at OSP HPS.
Tripping Details including the relay indications furnished by Senior Manager(E) Omkareshwar Power Station is also enclosed
as annexure – I to XII.
Remedial Measures
Auxiliary/Station supply at Omkareshwar HPS was resumed by charging 220 KV Omkareshwar – Barwaha Ckt. at 21:38
Hrs. Subsequently following feeders were charged and units were synchronized:-
1. 220 KV Omkareshwar – Nimrani (Tap Barwaha) Ckt. – at 21:53 Hrs.
2. 220 KV Omkareshwar – Chhegaon Ckt. – at 22:03 Hrs.
3. 220 KV Omkareshwar – Julwaniya Ckt. – at 22:21 Hrs.
4. Unit No: # 4 – at 22:35 Hrs.
5. 220 KV Omkareshwar – Khandwa Ckt. – at 23:18 Hrs.
6. Unit No: # 5 – at 23:21 Hrs.
Conclusion: The above tripping occurred due to high voltage at OSP HPS. The high voltage in the system was observed as there
was sudden crash in M.P. demand due to rains in Western part of the state.
Generation loss:- NIL
Load Loss: There was no load loss during the occurrence at OSP HPS.
Ckt - II
220 KV S/s
Chhegaon
Khandwa
Omkareshwar Power
Station
(220 KV Bus - I)
132 KV S/s C.
220 KV S/s
Khargone
Nimrani
132 KV S/s
Sanawad
GEN - 7 GEN - 5 GEN - 3 GEN - 1
220 KV S/s
Chhegaon
Omkareshwar Power (132 KV Bus)
Station
(220 KV Bus - II) - Breaker Close
- Breaker Open
220 KV S/s
Julwania
- Breaker Tripped
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Annexure - 2.30
COMMENTS OF SLDC
Pre-Fault Condition : On dated 13.11.14 at around 12:40 Hrs. MP system was normal and frequency was 49.85 Hz.
Prior to the fault 400 KV SGTPS Birsinghpur – Katni Ckt – I was open from both ends due to over voltage.
Remaining 440 KV & 220 KV feeders at SGTPS, Birsinghpur were in charged condition and normally loaded. At
SGTPS Unit No. – 3, 4 & 5 were on bar and Unit No. – 2 was light up at 11:04 Hrs.
The 400 KV Bus Bar Protection is installed and is in working condition whereas 220 KV Bus Bar Protection is
not commissioned so far.
The Bus configuration at 400 KV and 220 KV is of DMT Bus scheme. The feeder arrangement and their
loading prior to fault were as follows:-
400 KV MAIN BUS – I 400 KV MAIN BUS – II
Loading Loading
S.No. Name of Feeders/X’mers S.No. Name of Feeders/X’mers
in MW in MW
1. 400/220 KV, 3X167 MVA ICT 51 1. Unit No. – 5 495
2. 400 KV SGTPS Birsinghpur – Katni – II 399 2. 400 KV SGTPS Birsinghpur – Katni – I 0
3. 400 KV SGTPS Birsinghpur– Balco Ckt. -317 3. 400 KV SGTPS Birsinghpur – Damoh – I 340
4. 400 KV SGTPS Birsinghpur – Vandana Ckt. -354 4. 400 KV SGTPS Birsinghpur – Damoh – II 340
220 KV feeder arrangement and their loading prior to fault were as follows:-
220 KV MAIN BUS – I 220 KV MAIN BUS – II
Loading Loading
S.No. Name of Feeders/X’mers S.No. Name of Feeders/X’mers
in MW in MW
1. Unit No. – 1 (210 MW) 0 1. Unit No. – 2 (210 MW) 0
2. Unit No. – 3 (210 MW) 172 2. Unit No. – 4 (210 MW) 181
3. 220 KV Interconnector - I 95 3. 220 KV Interconnector - II 89
4. 220 KV Interconnector - IV 36 4. 220 KV Interconnector - III 36
5. 220 KV SGTPS Birsinghpur – Sukha Ckt 91 5. 220 KV SGTPS Birsinghpur – Satna Ckt 62
6. 220 kV SGTPS Birsinghpur – Amarkantak III -25 6. 220 kV SGTPS Birsinghpur – Amarkantak II -34
7. 220/6.6 KV, 40 MVA Station X’mer - I 7 7. 220/6.6 KV, 40 MVA Station X’mer - II 9
8. 400/220 KV, 3X167 MVA ICT -51
Occurrence: On Dated 13.11.2014, SGTPS Unit No. – 2 was Light up at 11:04 Hrs. For synchronizing Unit No – 2
(210 MW), “Close” command was manually given to generator breaker. But immediately after giving the “Close”
command to generator breaker at 12:46:07.212 Hrs. its 220 KV ‘R’-Phase pole burst (producing two no. heavy blast
sounds) creating the 220 KV Bus Fault and following feeders, units and X’mers tripped:-
Tripping Time
S.No. Name of Feeder/transformer Tripping End Indication
(as per SOE)
DPR optd., Zone – II at
1. 220 KV SGTPS – Sukha Ckt 220 KV S/s Sukha 12:46:11.854
remote end.
2. 220 KV SGTPS – Amarkantak – II SGTPS 12:46:14.285 DPR optd., Zone – I.
3. SGTPS Unit No. – 3 (210 MW) SGTPS Birsinghpur 12:46:14.736 REF
4. SGTPS Unit No. – 4 (210 MW) SGTPS Birsinghpur 12:46:14.759 REF
DPR optd., Zone – I at
5. 220 Interconnector – I. SGTPS Birsinghpur 12:46:14.762
remote end.
220 KV S/s DPR optd., Zone – I at
6. 220 Interconnector – IV. 12:46:14.055
Birsinghpur Pali remote end.
DPR optd., Zone – II at
7. 220 KV SGTPS – Satna Ckt. 220 KV S/s Satna 12:46:15.302
remote end.
SGTPS End:- General trip,
DT receive, DPR operate.
8. 400 KV SGTPS – Damoh Ckt-I. Both End 12:46:16.066
Damoh End:- DT receive,
DPR operate.
SGTPS End:- General trip,
DT receive, DPR operate.
9. 400 KV SGTPS – Damoh Ckt-II. Both End 12:46:16.069
Damoh End:- DT receive,
DPR operate.
220 KV S/s DPR optd., Zone – I at
10. 220 Interconnector – II. 12:46:14.069
Birsinghpur Pali remote end.
SGTPS End:- General trip,
11. 400 KV SGTPS – Vandana Ckt. Both End 12:46:16.070
DT receive, DPR operate.
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Due to the above tripping there was total interruption at SGTPS Birsinghpur for about 55min.
The 48VDC supply to PLCC and telemetry interrupted due to poor condition of battery. Thus the telemetry and
PLCC communication was out during disturbance.
The field report on the basis of during & post fault observation & discussion with OEM suggests probability of
fault as given below:-
“The breaker got closed after getting check synchronizing relay permissive and closing command thereafter.
During closing procedure, the ‘R’-Phase pole insulator got shattered. As a result, SF6 gas escaped to
atmosphere and it got exposed to air and ionization of surrounding air caused arching earth fault and
tripping command to Generator Breaker initiated. But as no quenching medium was available for ‘R’-Phase
Pole, this pole got heated and its moving metallic contact was found in stretched/bend/molten/broken in
elastic condition. Pole got pulled downwards and upper portion along with line side conductor dropped on
ground. Due to arching, a heavy blanketing of ionized air surround the lower portion of breaker, causing
Bus side arching earth fault. The two blast sounds supposed to be of following:-
1. First one of shattering of upper breaker portion.
2. Second one was dropping of upper portion of breaker on ground and forming blanket of heavy arch by
ionization of air.
Picture of damaged breaker in soft & hard copy enclosed.”
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220 KV S/s
PGCIL
MPPTCL
Anuppur
220 KV S/s
Sidhi
Vandana
400 KV
220 KV S/s
Balco
400 KV
GEN - 5
Satna
220/6.9 KV, 40 MVA
{
220/6.6 KV, 40 MVA
{
{
Stn. X'mer
Stn. X'mer
GT-5
220 KV
Amarkantak TPS
400 KV S/s
Birsinghpur (SGTPS)
(440 KV BUS)
Ckt - III
Ckt - II
400/220 KV,
Ckt - II
3X167MVA
ICT
400 KV S/s
Birsinghpur (SGTPS)
(220 KV BUS-I)
Coupler
Bus
GT - 4 GT - 1 Interconnector - IV
250MVA 400 KV S/s
Interconnector - I
250MVA
Birsinghpur
(SGTPS)
Interconnector - III
Interconnector - II
(220 KV BUS-II)
GT - 2 GT - 3
250MVA 250MVA
GEN - 4 GEN - 1
220 KV S/s
Birsinghpur GEN - 2 GEN - 3
Pali 400 KV S/s
Jabalpur (Sukha)
- Breaker Close
(220 KV Bus)
- Breaker Open
- Breaker Tripped
220 KV Railw ay
220 KV Railw ay
Traction - II
Traction - I
Birsinghpur HPS
(220 KV BUS) 220 KV S/s
Jabalpur
}
220 KV S/s
Narsinghpur
Remedial Measures:- Supply at SGTPS Birsinghpur was resumed by charging 220 KV Interconnector – I at 13:30Hrs.
subsequently following feeders and transformers were charged:-
S.No. Name of Feeders & X’’mer Charging Time (in Hrs.)
1. 220/6.6 KV, 160 MVA Stn. X’mer – I & II at SGTPS. 13:40
2. 220 KV SGTPS – Amarkantak Ckt – II. 13:50
3. 220 KV Interconnector – II 13:55
4. 400 KV SGTPS – Vandana Ckt. 15:14
5. 400 KV SGTPS – Katni Ckt - II 15:32
6. 400 KV SGTPS – Damoh – I 15:37
7. 400 KV SGTPS – Balco Ckt. 15:47
8. 400/220 KV, 3X167 MVA ICT at SGTPS 16:21
9. 220 KV SGTPS – Sukha Ckt. 17:06
10. 220 KV Interconnector - III 17:09
11. 220 KV Interconnector - IV 17:21
12. SGTPS Unit No. – 3 (210 MW) 18:40
13. SGTPS Unit No. – 4 (210 MW) 00:20 Dtd. 14.11.2014
14. 400 KV SGTPS – Damoh Ckt – II 10:14 Dtd. 14.11.2014
15. 220 KV SGTPS – Satna Ckt 11:24 Dtd. 14.11.2014
16. SGTPS Unit No. – 5 (500 MW) 12:46 Dtd. 14.11.2014
17. 220 KV SGTPS – Amarkantak – III 10:35 Dtd. 15.11.2014
18. SGTPS Unit No. – 2 13:44 Dtd. 17.11.14
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Due to above tripping there was sudden generation loss which led to overloading of 400/220 KV, 315 MVA ICT
– I & II at 400 KV S/s Satna (PGCIL). The loading details of ICT’s are as below:-
S.No. Time in Hrs. Loading(MW)
400/220 KV, 315 MVA ICT – I at 400/220 KV, 315 MVA ICT – II at
400 KV S/s Satna (PGCIL) 400 KV S/s Satna (PGCIL)
1. 12:45:00 (Prior to fault) 243.129 221.100
2. 12:46:00 243.129 221.100
3. 12:47:00 (After the fault) 364.094 328.916
4. 12:48:00 367.095 332.041
To avoid over loading and tripping of Satna ICT instructions were issued to East Discom to take load shedding
of about 105 MW from 13:05 Hrs. to 15:35 Hrs. and further following measure were taken:-
1. 220 KV Katni – Damoh Ckt was opened at 12:57 Hrs. as power was flowing from 400 KV S/s Katni to
220 KV S/s Damoh.
2. 132 KV Satna – Panna Ckt (Radial feeder) was Hand Tripped at 13:05:43 Hrs. (26 MW load.)
3. 132 KV Satna – Pawai Ckt (Radial feeder) was Hand Tripped at 13:05:51 Hrs. (41 MW load.)
4. 132 KV Satna – Majhgawan Ckt (Radial feeder) was Hand Tripped at 13:06:25 Hrs. (5MW load.)
5. Tons Unit No. – 1 was synchronized at 13:20 Hrs.
6. Tons Unit No. – 2 was synchronized at 13:30 Hrs.
To compensate generation loss machines at Tons HPS, ISP HPS and OSP HPS were synchronized
Conclusion
On Date 13.11.2014, the tripping occurred as 220 KV ‘R’-Phase Pole of Generator Breaker of SGTPS Unit
No.-2 burst and creating the 220 KV Bus fault.
The 220 KV ‘R’-Phase Pole of Generator Breaker burst at 12:46:07.212 Hrs. creating the Bus Fault and all 220
KV feeders tripped from either end with considerable delay.
The tripping of 400/220 KV, 3X167 MVA ICT occurred at 12:47:48 Hrs.(as per DR) with considerable delay,
which should have tripped immediately after the fault. There was a delayed fault clearance of about 1min
41sec. due to which fault was fed through 400 KV system and resulted in tripping of all connected 400 KV
feeders. Consequently Unit No. – 5 (500 MW) tripped due to over speeding and on Back-up impedance
protection.
There was a delayed fault clearance hence settings of relays of 400/220 KV, 3X167 MVA ICT and all
connected 220 KV & 400 KV feeders and Generator protection need immediate review as per CBIP & CEA
standards not only at SGTPS Birsinghpur but also at other power stations owned by MPPGCL.
The 220 KV Bus Bar protection is not commissioned at SGTPS & also at other MPPGCL switchyards. The Bus
Bar & LBB protection at 220 KV & 400 KV switchyard is mandatory requirement and should be installed on
top priority confirming to CBIP & CEA standards. It is the responsibility of individual switchyard owner to
ensure its all-time healthiness.
Till 220 KV Bus Bar protection is commissioned, the relay settings of 220 KV Bus Coupler may be adjusted
such that the Bus Coupler Breaker trips isolating the Buses. This will clear the fault before spreading to other
elements.
MPPGCL should avail services of OEM M/s CGL for detailed analysis of this failure and submit its report. The
Circuit Breaker (CGL make, mfg. yr-1991) has completed 21yrs of service useful life & may be considered for
replacement.
The static relays, if installed on any feeder/transformer at all power station having 400 KV and 220KV
switchyard should be replaced with numeric type relays as per CBIP & CEA recommendations. Similarly if
Bus Bar protection is of static relay then the same should be replace with numeric relay.
It is gathered that relay time synchronization is not available through GPS and hence the trigger time
discrepancies in DR printout is in seconds. This needs corrective measure immediately.
DC leakage at SGTPS switchyard may be checked and if found, corrective measures may be taken.
48 Volt DC battery set is in very poor condition and needs immediate replacement.
Load Loss:- 180 MW from 13:05 Hrs. to 15:35 Hrs. (450 MWH) due to load shedding.
Generation Loss:- 847 MW.
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Annexure - 2.31
Sub: Occurrence analysis of Occurrence on dated 29/11/2014 at 220kV South Solapur s/s.
On dated 29.11.2014 at 00:40 Hrs 132 kV ‘B’ phase PT of M/s. Mehru make of Section II was
failed at 220 kV South Solapur substation which causes selective operation of 132kV Bus bar
protection (M/s. AREVA make P742) resulted into failure of supply at 220kV South Solapur S/S.
Relay & Window Indications are as below:
Window indication: 132kV Bus bar protection operated
Relay Indication:
A) 132 kV Bus bar panel Bus bar relay (Make AREVA, Type P742)
1) Zone 1 trip 2) B phase fault.
B) 132 kV Akkalkot panel 1) 96 relay
C) 132 kV Bus Sectionalizer 1) 196 relay
D) 220/132 kV, 100 MVA ICT no. II 1) LV 96 relay
E) All 132 kV Bays on Bus bar PU: Zone I and B phase LED indication
F) 220 kV South Solapur – PGCIL line no. II 1) Direct trip received. 2) 86 Tripping relay
Analysis:
132 kV Bus bar protection operated correctly. Simultaneously in distance relay directional E/F
was operated of 220kV PGCIL – Solapur circuit no. II at PGCIL substation which gave direct trip
command to 220kV South Solapur end. The operation of Dir.E/F protection at PGCIL end after
operation of selective 132kV Bus bar protection at 220kV South Solapur substation is not desirable.
At PGCIL end for 220kV PGCIL – South Solapur lines Main I & Main II distance protection are
provided. Bus fault of 220kV South Solapur substation should be covered in Zone-II distance
protection of 220kV PGCIL – South Solapur lines . However line trips on Dir.E/F protection which is
questionable. Matter referred with PGCIL.
Failed 132kV PT Details: Make: M/s. Mehru , Sr.no. OP 3071/3/1/10, Year of Manufacturing- 2010
Remedial Action: Matter needs to be taken with M/s. Mehru regarding the cause of PT within a very
short period.
Sd/-
Superintending Enineer, TCC, Pune
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S. Trip Restored A/R
Element Reason
No. Date Time Date Time Status
1 400 kV Birsingpur - Katni - II 04.09.2014 3:35 05.09.2014 22:29 Line tripped due to O/V at Katni end
2 400 kV Birsingpur - Katni - II 06.09.2014 13:16 06.09.2014 18:49 Line tripped on E/F
3 400 kV Birsingpur - Katni - II 07.09.2014 13:01 07.09.2014 19:01 Line tripped due to O/V at Katni end
125 MVAR reactor at 400 kV Bus reactor charged from SCADA and tripped on B & C ph differential
4 08.11.2014 17:57
Warora S/s protection .
5 400 kV Birsingpur - Katni - I 10.09.2014 12:09 22.09.2014 14:52 Line tripped due to O/V at Katni end
6 400 kV Birsingpur - Katni - II 13.11.2014 12:46 13.11.2014 15:46 Line tripped due to heavy jerk on SGTPS sattion
7 440/220 kV ICT at Sarni S/s STPS 15.09.2014 9:58 15.09.2014 13:25 Line tripped due to O/V at Katni end
400 kV JPL - Stg - I - Stg - II
8 15.102.104 14:44 17:49 Interconeector tripped due to Y ph fault
interconnector
9 220 kV TAPS - Boisar 16.10.2014 12:10 23.09.2014 13:35 Line tripped on C ph fault
10 Sipat - Raipur # III 16.11.2014 06:08 Line tripped on receiving DT
11 Sipat - Raipur # III 16.11.2014 13:29 Line tripped on receiving DT
12 Sami Dehgam 17.11.2013 03:41 17.11.2014 04:15 Line tripped on distnce protection
13 220 kV TAPS - Borivali 23.09.2014 6:56 23.09.2014 16:21 Line tripped on backup O/C
14 220 kV TAPS - Vapi 24.09.2014 11:13 24.09.2014 11:52 Line tripped on zone - II distance protection
15 400 kV Birsingpur - Katni - I 30.09.2014 17:46 30.09.2014 19:45 Line tripped due to O/V at Katni end
96
1
1
97
1
1
98
1
1
99
1
1
Annexure - 4.1.2
Present Status of Protection Audit Deficiencies (A & B type) in MSETCL for the year 2012-13 as on 19/12/2014
1 2 3 4 5 6 7 8 9 10 11
Deficiencies that can be
Deficiencies involving
corrected without
Name of S/s S/s procurement (Category-B)
Sr. procurement (Category-A) Present Status as on
identified for voltage Observations of protection Audit
No. Whether If not Whether 30/09/2014
Protection Audit (kV) Yes/ Yes/ If no, expected
attended attended, attended
No No date to attend
Yes/No reason Yes/No
Faulty Annuciators shall be replaced Replaced on dt.
1 Wardha 220 Yes Yes 31.08.14
immediately 15.09.2014
The annunciator of 220kV TSS-I &
Replaced on dt.
2 Hinganghat 220 Warora are out of service which need to Yes Yes 30.09.14
09.08.2014
be replaced immediately.
The Differntial relay of 220/33kV 50MVA Replaced on dt.
3 Warora 220 Yes Yes 31.08.14
T/F-II shall be replaced 16.09.2013
Replaced on dtd.
4 Khaperkheda 400 The NDR relay shall be replaced Yes Yes 31.08.14
07.06.2014
Replaced on dtd.
5 Koradi 400 The NDR relay shall be replaced Yes Yes 31.07.14
11.06.2014
6 Deepnagar GCR 220 LBB scheme is not in service Yes No 31.12.14 work is in progress
100
1
1
Present Status of other issues identified during Protection Audit for system improvement in MSETCL for the year 2012-13
as on 19/12/2014
Name of S/s S/s
Sr. Expected date to
identified for voltage Observations of protection Audit Present Status as on 30/09/2014
No. attend
Protection Audit (kV)
The ABB make SCADA is in service with standby PC not in
1 VASAI 220 working condition. The GPS & SCADA timing is not ABB representative visited site on 23/07/2014 &
matching due to problem in GPS clock & system. Dec.-2014 in co-ordination with M/s ABB work will be
TF LV side data is not available at SCADA due to completed by Dec.-2014.
2 VASAI 220
communication failure problems.
Work is in progress.
3 VASAI 220 The 100kV Busbar protection scheme is not in service. Mar-15
However 220kV Busbar scheme is in service.
Commissioning of 2 Nosof 220kV Hybrid PASS (GIS Bus-
Within 1 Year (After
sectionalizer) at Padghe alongwith additional 220kV TBC,
4 PADGHE 400 receipt of material work is in progress.
2 sets of PTs & shifting of 220kV side bay of ICT3 &
at site)
strenthening of 400kV & 220kV Bus
Within 1 Year (After Existing schemes are in service. However,
Replacement of 220kV & 100kV static Busbar schemes by
5 PADGHE 400 receipt of material replacement by Numerical scheme is planned.
Numerical Busbar schemes.
at site) Pl. ref. **
Existing scheme is in service. However,
Replacement of 132kV Busbar protection schemes by
6 BOISAR 220 replacement by Numerical scheme is planned.
Numerical Busbar schemes.
Pl. ref. **
Existing scheme is in service. However,
Replacement of 400kV Static Busbar protection schemes
7 KALWA 400 replacement by Numerical scheme is planned.
by Numerical Busbar schemes
Pl. ref. **
Shifting of 500 MVA, 400/220kV ICT 1 from 400kV Kalwa II
8 KALWA 400 Completed.
ss to 220kV Kalwa I ss
The Control panels are very old & need
replacement. The scheme is being prepared by
9 URAN 220 All 220kV Control panels needs to be replaced. field office. However, as existing panels are in
service, there is no urgency & will be replaced
in a phased manner.
Existing scheme is in service. However,
Replacement of 100kV Busbar protection schemes by
10 APTA 220 replacement by Numerical scheme is planned.
Numerical Busbar schemes.
Pl. ref. **
The C & R panels are very old & need
replacement. The scheme is being prepared by
The C & R panels needs replacement with new Control
11 APTA 220 field office. However, as existing panels are in
Room.
service, there is no urgency & will be replaced
in a phased manner.
101
1
1
The work of shifting of 220kV C & R panels from old CR to Order is placed & work will be completed by
17 TROMBAY 220 Mar-15
newly constructed CR by REL is to be taken on priority. March 2015.
Internal module problems in the exisitng Busbar scheme Existing scheme is in service. However,
18 Kaulewada 220 (ALSTOM-PBLSB). The scheme is maloperated in the past replacement by Numerical scheme is planned.
hence needs to be replaced. Pl. ref. **
The exisitng Busbar scheme (ABB-RADSS) has Existing scheme is in service. However,
19 Bhandara 220 maloperated in the past due to RQDA module problem replacement by Numerical scheme is planned.
and hence needs to be replaced. Pl. ref. **
Replacement planed. However, in the mean
20 Kanhan 220 48V DC battery set must be replaced immediately 30.09.14 time set reconditioned between 25.03.2014 to
31.03.2014
21 Ambazari 220 The deffective 220V DC battery sets shall be replaced 31.12.14
48V DC set no:-1 efficiency observed as 60%. Battery set
22 Ambazari 220 31.12.14
needs replacement.
The exisitng Busbar scheme (ABB-RADSS) has Existing scheme is in service. However,
23 Ambazari 220 maloperated in the past due to RQDA module problem replacement by Numerical scheme is planned.
and hence needs to be replaced. Pl. ref. **
The exisitng Busbar scheme (ABB-RADSS) has Existing scheme is in service. However,
24 Khaperkheda 220 maloperated in the past due to RQDA module problem replacement by Numerical scheme is planned.
and hence needs to be replaced. Pl. ref. **
102
1
1
29 Waghala 220 Line B/U electromechanical relays - 10 31.03.15 Order for retrofit of Back up relays is issued.
Note: ** Tender has been finalizaed for procurement of 76 Nos. of Busbar protection schemes at various EHV substations in MSETCL. Busbar Protection
schemes will be tentatively receved at site by 31/03/2015 & commissioning works will be taken up thereafter.
103
1
1
104
1
1
106
1
1
3) Non availability of B/B differential & Bus Bar protection panel has been
Yes No 31.10.2014
LBB protection received
4)GPS is available however no relay is Relays have been synchronised
Yes No 31.05.2014
Korba West synchronised with it. with new GPS.
400
TPS 5) Replacement of ABCB with SF6 breakers Replacement of ABCB with SF6
& commissioning of isolator sequential breakers is included in the scope of
Yes No 31.03.2016
operation with ABCB opening. work of R&M of station proposed
in year 2015-16
1) Second DC system is recommended . Yes No 31.03.2015 In R&M
2) To renovate/retrofit Main-I & Main-II 05 no. Numeric Relays have been
Protection with numeric relays in all out retrofitted as MainI/II protection in
going feeders. the following feeders: KW-Churi I
Yes No 30.09.2014
& II,KW-DSPM, KW-KE I & II .
Rest will be fitted after the receipt
of ordered material.
3) Carrier Protection is not in service. 02 no. have
been
commission for other 4 feeders procurement is
Yes No 31.03.2016
ed in KEB- required
KWB inter
connectors
Korba West Bay control panels for SCADA
220 4) Disturbance Recoder and SER s are not
TPS system have been received .M/s
available.
Yes No 31.09.2014 ABB is being persuaded to
commission the same as early as
possible.
5) Non availability of Auto reclose scheme. After the commissioning of the
Yes No 30.09.2014 numeris relays will be put in
service
6) Non availability of B/B differential Old scheme to be replaced by new
Yes No 31.03.2015 one.Estimate is being sent for
approval.
8)GPS is available however no relay is After commissioning of SCADA
synchronised with it. panel, Relays will be
Yes No 31.03.2015
synchronised.GPS facility is
available in SCADA.
107
1
1
MfP'T"'c.,L-
~.--
MP Annexure - I
Name of
Deficiencies that can be
Sl. Sub-S tation S/S
corrected without
identified for Voltage Observation of Protection Audit Deficiencies involving procurement (Category-B) Remark
No. procurement (Category-
Protection kV
A)
Audit
108
1
1
Name of
Deficiencies that can be
Sub-Station . S/S
SL corrected without
identified for Voltage Observation of Protection Audit Deficiencies involving procurement (Category-B) Remark
No. procurement (Category-
Protection kV
A)
Audit
r
:,1
,.
109
1
1
w
..r .,.
~
I-<Y\·S~)
110 •
1
1
••
-lARDING IMPLEMENTING PROTECTION AUDIT RECOMMENDATIONS AND CERC - Reg https://mail.googlc.com/mail/u/Ol?ui=2&ik=b3d635c8bd&vicw=pt&cat=fortnight data grid dis
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This has reference to your message dated 31-07·14 on the above subject. The point and extract of the romarks from our consultant MIS TCE forwarded to you long ago arc given below once again. However initial data compilation and studies by MIS CPRI ,Bangalore for
the protection co ordination by third party as per recommendation from grid failure committee has already been conducted in the 4th week ofjuly 2014 and there draft report will be available by 2 months. Discussion regarding all these point will be held at that time and a
conscious decision will be taken at that time
'Iame of
SiS Defideccies that can be
SL Sub-Station Df!icienaes ervclving
Voltage Observational Prctec ton .A,udlt corrected without Remark
No. ~idertifi ed for prccuren eu (C"'~'Orr3)
kV prccuremera (CategiXy-A)
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IUJCOIttntendsdfOt' G~ItiUa1Dr'mO'8 tJuz.n.l00 .MVA. rovid8d on.ly whtlt! SpedFLCallj" consuuant: )1:S I
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Regards.
S.K. Chakraborty
111
iii.
1
1
Part-1
Logic Check (Protection Audit Report) during year 2008-09-10
No. of No. of No. of defects No. of
Sr. Year of No. of SS
Particular Defects defects Pending Defects Category Defects
No. Audit Audited
observed attended A Category B
112
1 Logic check of 220/132 KV class substations 2008-09 (132 KV -48 2652 2652 nil 2652 Nil
220 KV-64 )
2 Logic check of 400 KV class substations 2009-10 9 1129 1129 nil 1129 Nil
Remark:- Audit was conducted during period 2008 to 2010 . All the defects have been successfully resolved.
Part-2
Logic Check (Protection Audit Report) during year 2013-14
121
1 Logic check of 220/132 KV class substations 2012-13 (132 KV -47 1191 1191 nil 1191 Nil
220 KV-74 )
2 Logic check of 400 KV class substations 2013-14 11 611 377 234 611 Nil
Remark:-(1) Audit of 121 nos. of 220/132 KV class substations is completed. All pending defects are atttended which falls in category A.
(2) Audit of 11 nos. of 400 KV substations is completed. Following nos. of bays are pending at SS.
(i) 400 KV Asoj- 10 nos.
(ii) 400 KV Kosamba:- 3 nos.
(III) 400 KV Vadavi- 1 nos.
112
1
1
116
1
1
117
1
1
Annexure - 4.2
TRANSFORMER PROTECTION DETAILS (Differential Relay Settings)
Any other
5th
over over protection
NAME OF Break second harmo
Relay Relay High High fluxing fluxing over load DTOC element
S No. FEEDER / S.NO. pick up slope 1 slope 2 point of harmonic nic DTOC 1 REF REMARK
MAKE Type set 1 set 2 stage 1 stage 2 Alarm 2 enabled
XMER slope 1 blocking blocki
Alarm Trip for trip or
ng
alarm
Line
Positive Sequence Impedance
Zero Sequence Impedance
LINE PROTECTION RELAY SETTING DETAILS LBB Settings BUS BAR PROTECTION DETAILS
NAME OF LBB Setting
S Relay Relay 400/220K Relay Relay Relay Bus Bar
FEEDER / S.NO. Length of line Time Remarks S. No. Remarks
No. MAKE Type PS V BUS Make Type Sr.No. Setting
XMER Delay
118
1
1
Annexure - 5.1.1
FORMAT -1 (PROTECTION AUDIT)
Recommendation 9.1.1: There is a need to review protection schemes. This Committee concurs with recommendation of previous enquiry committee that a throrough third party protection audit need to be carried out in time bound manner.
Agency
This exercise should be repeated periodically and monitored by RPC's. Action : RPCs, CTU, STUs.
(D)Target date for (E ) No. of S/S where
State (A) Total No. of S/S in region. (B) No. of S/S identified for audit. ( C) No. of S/S yet to be audited completion of audit. deficiencies detected.
132 kV 220 kV 400 kV 765 kV HVDC Total 132 kV 220 kV 400 kV 765 kV HVDC Total 132 kV 220 kV 400 kV 765 kV HVDC Total
Maha 119 119 0 NA NA
Guj 47 81 11 47 81 11 0 0 0 NA 139 (47+81+11)
CG
MP gen 9 4 2 15 9 4 2 0 4 2 6 01/11/2014 NA
1. RPCs Trans+JP 54 8+1 54 8+1 54 0+0 31/12/2014
(State OSP 1 1 1 30/09/2013 Tendered
wise) ISP 1 1 1 30/09/2013 Under Tendering
WR-I (PG) 0 0 8 3 1 0 0 8 3 1 0 0 0 0 0 0 NA NA
WR-II (PG) 11 3 11 3 4
2. CTU WR-I (NTPC)
(Region WR-II (NTPC)
wise) Total
(I) Reason/remarks for
(F) Action plan (on observation of third party (G) Detail of S/S where no procuremnet is required for
(H) Detail of S/S where procurement is required. No. of SS rectification of deficiencies (J) Cost estimates for
protection audit) finalization date/Target date for removal of deficiencies. No. of S/S
Target date of removal of deficiencies. requiring period of more removal of deficiencies.
finalizing plan Target date for removal of deficiencies
than one year.
132 kV 220 kV 400 kV 765 kV HVDC Total 132 kV 220 kV 400 kV 765 kV HVDC Total 132 kV 220 kV 400 kV 765 kV HVDC Total
Maha NA NA NA NA NA
Guj
CG
MP
WR-I (PG) NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
WR-II (PG) 2 3
WR-I (NTPC)
WR-II (NTPC)
119
1
1
120
1
1
Format -3
Details of existing PMUs Additional PMUs planned to be insatlled Total No. of
S No. Constituent No. of PMUs No. of PMUs functional and Target date for making Target date for PMUs in the
Locations No. of PMUs Locations
installed time syndchronised defective PMU functional commissioning State
Maha 15 35 50
Guj 0 25 25
CG
MP 2 2
WR-I (PG)
WR-II (PG) 8 8
WR-I (NTPC)
WR-II (NTPC)
Maharastra
No. of units Target date to
S. NO. WR II No. of PMUs Location functional & Time Make defective
Voltage (kV) PMU Location Synchronised PMUs functional
1 400 Chandrapur 1 1 Satna 1 Under Operation
2 400 Bhusawal 2 3 Itarsi 3 Under Operation
3 400 New Koyna 3 2 Jabalpur 2 Under Operation
4 400 Padghe 4 1 Dehgam 1 Under Operation
5 400 Dhule 5 1 Vapi 1 Under Operation
6 400 Kalwa
7 400 Kolapur
8 400 Aurangabad
9 400 Lamboti
10 400 Lonikand
11 400 Girwali
12 220 Trombay
13 220 Eklahare
14 220 Boisar
121
1
1
S. Name of
Aim Description Commissioned on Agency
No. the SPS
Stage-1:-700 A, 5 Minutes.
Ukai - To restrict overloading Stage-2 : 750 A, Instantaneous
1
Mota D/C on 220 KV Ukai-Mota- D/C lines (It will cut off load of 66 kV System at 220
KV Mota and Ambheta S/s)
Stage-1:-660 A,5 Minutes.
Amreli - To restrict overloading
Stage-690 A, Instantaneous
2 Savarkindla on 220 KV Amreli-Savarkundla
(It will cut off load of 66 kV System at 220
D/C D/C lines
KV Savarkundla S/s)
To restrict the loading on 150
Setting HV current :- 360 A
MVA, 220/132 KV ICT at 400
Rated HV Current: 394 A
3 Asoj ICT KV Asoj S/s in case of the 23/07/2013
(It will trip 132 KV Asoj-Manjusar line no.
sudden loss of GIPCL generation
1 &2.
.
Setting HV current :- 231 A
To restrict the loading on
Rated HV Current: 262 A
220/132 KV transformers at 220
4 Jambhuva (It will trip 132 KV Karjan, Tilakwada. 66
KV Jambuva S/s in case of the
KV Dabhoi, 66KV Tarsali 1 &2)
sudden loss of GIPCL generation
Commissioned on 29/7/13
Stage-1:- 500 MW, 10 Sec - Alarm
APL - Sami To restrict overloading of 400 Stage-2:- 650 MW, 03 Sec - Tripping of
APL, Mundra
5 - Dehgam KV D/C APL-Sami-Dehgam APL Unit No. 3 or 4
(W/O FSC)
(W/O FSC) lines without FSC. Stage-3:- 750 MW, 01 Sec - Tripping of
one 660 MW Unit.
Stage-1:- 500 MW, 10 Sec - Alarm
APL - Sami To restrict overloading of 400 Stage-2:- 750 MW, 03 Sec - Tripping of
6 - Dehgam KV D/C APL-Sami-Dehgam APL Unit No. 3 or 4
(With FSC) lines with FSC. Stage-3:- 800 MW, 01 Sec - Tripping of
one 660 MW Unit.
Stage-1:- 500 MW, 10 Sec - Alarm
APL -
To restrict overloading of 400 Stage-2:- 750 MW, 03 Sec - Tripping of
Hadala &
7 KV APL-Varsana & 400 KV APL Unit No. 3 or 4 APL, Mundra
APL -
APL-Hadala lines Stage-3:- 850 MW, 01 Sec - Tripping of
Varsana
one 660 MW Unit.
Stage-1:- 500 A, 05 Sec - Alarm
APL -
To restrict overloading of 220 Stage-2:- 550 A, 02 Sec - Tripping of any
Nanikhakka
8 KV D/C APL-Nanikhakhar & one 400/220 KV, 315 MVA ICT at APL APL, Mundra
r & APL -
220 KV D/C APL-Tappar lines Stage-3:- 605 A, 05 Sec - Generation
Tappar
backing down.
Gwalior S/S - 765kV Gwalior-
Agra -
9 Agra ckt.1 & 2 - For Load WR II
Gwalior
Shedding in Northern Region
Gwalior S/S - 220kV
Gwalior
Gwalior(PG)-Gwalior(MP) &
(PG) -
10 Malanpur-For Tripping of 220 WR II
Gwalior
kV lines at Gwalior (PG) S/s in
(MP)
case of tripping of 765kV lines
When 400kV Pathadi-Raipur
LANCO-
11 trips, I unit of 300MW of Aug-10 M/s LANCO
Pathadi
LANCO has to be tripped.
122
1
1
123
1
1
Guj NA 10 TBD
145 145 0
CG
MP+JP 33+2 33+2 0 1 Dec-14
OSP 0 0 0
ISP 12 12 0
WR-I (PG)
WR-II (PG)
WR-I (NTPC)
WR-II (NTPC)
124
1
1
POSOCO
(Petition No. and details of petitions filed with CERC for non-compliance Brief of petitionfiled in CERC Status of Petition
wise) of various regulations, issued under the act, by the states
WRLDC 22 22
Maha
Guj
CG
MP
WR-I (PG)
WR-II (PG)
WR-I (NTPC)
WR-II (NTPC)
125
1
1
In detail
S. Presently
Petition No. Petitioner Respondent Allegation Present Status
No. case is with
1. PTC India Ltd., 2.
HPGCL 3. Chhattisgarh Application to fix/approve tariff for sale and
State Power Trading Co. purchase of power for the dispute period from
HERC/PRO-01 Lanco Amarkantak Pending. Supreme Court stayed the proceedings at
1 Ltd. 4. Western Regional HERC Unit-2 of Lanco Amarkantak Power Ltd. to PTC
of 2012 Power Ltd. HERC
Load Dispatch Centre 5. as per Hon’ble Supreme Court Order dated
Central Electricity 16.12.2011. Currently stay by Supreme Court
Regulatory Commission
1.Haryana Electricity
Civil Regulatory Commision
Lanco Amarkantak Supreme Dispute over termination of PPA/revision of
2 Appeal.No.1032 2.WRLDC 3.CSPTCL Pending
Power Ltd. Court of India tariff/APTEL order
9/2011 4.Union of India,Ministry
of Law
Pending - PGCIL,POSOCO&WRLDC Respondent
N0 1,2,& 3 had filed an Appeal (Appeal.No.233/2013
& IA.No.318/2013) at APTEL against the jurisdiction
CSPDCL has filed a petition at CSERC against of CSERC in the present petition. Hearing held on
WRLDC& PGCIL on allowing generators within 23/05/13 & 16/07/13 & 03/05/2014. Last hearing at
PGCIL, POSOCO,
3 Pet.19/2013(M) CSPDCL CSERC geographical area of Chhattisgarh state to draw APTEL on 28.04.2014 (matter clubbed with another
WRLDC
power for startup and commissioning activities in appeal - 86/2014, wherein EMCO & WRLDC have
line with CERC Regulation been impleaded as parties. ) APTEL had stayed the
proceedings at CSERC till further order from
APTEL. CSERC had scheduled the matter on
09.10.2014 to observe the latest position.
Pending. The appeal has been clubbed with appeal no.
Appeal.No.233/2 PGCIL,POSOCO&WRLDC Respondent N0 86/2014, whenein WRLDC and EMCO have been
4 013 & WRLDC/PGCIL CSPDCL APTEL 1,2,& 3 had filed an Appeal challenging the impleaded as parties. Last date of hearing was
IA.No.318/2013 jurisdiction of CSERC in pet no. 19/2013 02.09.2014. The proceedings have concluded and the
case is reserved for orders.
WRLDC along with EMCO has been impleaded as
13 respondents including: An appeal has been filed by CSPDCL against a parties in the said appeal. Detailed arguments were
Appeal
5 CSPDCL PGCIL, POSOCO & APTEL combined order of CERC dt. 18/09/2013 (In heard on 21/8/2014.Last date of hearing was
No.86/2014
WRLDC petition no. 27/RP/2012 and 259/MP/2012). 02.09.2014. The proceedings have concluded and the
case is reserved for orders.
As per thr order a report was to be submitted to CERC
by 08.08.2014 in consultataion with CEA. A letter
SASAN, IE, 14
Declaration of CoD by SASAN UMPP at a along with detailed report has been sent to CEA
6 Pet.No.85/MP/2012
WRLDC beneficiaries of SASAN CERC
derated capacity requesting them to convene a meeting to discuss and
UMPP
finalise the report to be submitted to the Hon'ble
Commission.
126
1
1
MPPMCL has filed the petition at High Court,
Jabalpur, challenging Regulation 7 DSM reg
2014 with a prayer to declare the
Ministry of Power, CEA, M P High
Regulation/clause 7 as ultra-vires and not Pending. Last heard on 20/03/14. Reply has been
7 Pet.No.3125/2014 MPPMCL CERC, WRLDC, WRPC, Court
enforceable on the petitioner, any other suitable filed by us. Case is yet to be listed for final hearing.
SLDC(MP) (Jabalpur )
relief in favour of petitioner and to stay the
operation and effect of Reg 7 of DSM Regulation
2014.
A petition has been filed on behalf of the
APDISCOMS: KSK Mahanadi, SRLDC,
APDISCOMS for directions on illegal claim of WRLDC & SRLDC are not direct parties to the
APCPDCL, WRLDC, AP SLDC,
APERC, Rs. 66.31 Crores towards transmission charges petition and have pleaded to be removed from the list
8 Pet.No.14/2014 APEPDCL, M/S. Shading Electric
Hyderabad and capacity charges, including late surcharge fee of parties. Last heard on 26/04/2014. case is listed for
APNPDCL, Power Construction
by illegal invoking of the Letter Of Credit by M/S hearing on 20.09.2014.
APSPDCL, APPCC Company
KSK Mahanadi Power Company Ltd.
JPL had challenged the Open Access Regulation
Pending. Appeal was admitted on 10/3/2014 . Reply
Appeal.No.58/20 CERC,PGCIL,NLDC,WR 2009 stating that against an LTA of 500MW JPL
9 Jindal Power Ltd. APTEL has been filed by WRLDC & NLDC.Scheduled for
14 LDC is not getting any prefernce in STOA applicatons
hearing on 13.10.2014.
by JPL.
case over. The order in pet. 211/MP/2011 was upheld
Petition No. Steel Authority of SAIL had filed a review petition of the order
10 WRLDC CERC by the commission, thus dismissing the review
2/RP/2014 India Ltd. dated 20.11.2013 in petition no. 211/MP/2011.
petition.
Last ROP dated 10.7.2014. Appeal has been admitted
Appeal no. An appeal has been preferred by SAIL against the
11 SAIL/BSP CERC & WRLDC APTEL and case is scheduled for hearing on 17.10.2014. We
41/2014 order dated 20.11.2013 in pet no 211/MP/2011
are yet to file our reply.
Last date of hearing was 5.09.2014 wherein the case
CERC,MP Power
Appeal No. An appeal has been filed against CERC order in got adjourned. The reply has been filed by us and the
12 CSPDCL Management Co., WRPC APTEL
95/2014 petition no. 193/MP/2012 (order dt. 20/02/2014). the case has now been listed for hearing on
& WRLDC
13.10.2014.
Pending. Admission hearing over, two replies have
been submitted by WRLDC 1.) reply to the pet 2.)
Dispute between NTPC & WR beneficiaries on
WRPC,WRLDC all Reply in response to the replies of GUVNL &
Pet.No.114/MP/2 scheduling under fuel shortage conditions and
13 NTPC beneficiaries of NTPC in CERC MSEDCL. A detailed hearing took place on
013 interpretation of clause 21.4 of TCT Regulation
WR 30.09.2014 wherin GUVNL has submitted additional
2009-14
affidavits and NTPC filed a counter reply. Next date
of hearing is awaited.
EMCO has filed a petition against DNH Corp. for
DNH Power Distribution recovery of capacity charges arising due to non- WRLDC is an indirect party to the petition and has
Petition no.
14 EMCO Corporation ltd., Power CERC scheduling of Power as per tye terms of the PPA been impleaded as a party only at the direction of
53/MP/2014
Grid, GETCO & WRLDC executed between EMCO & electricity CERC. Listed for hearing on 31.10.2014.
department of DNH
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128
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1
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( C) Audit of SVC
Action plan with timeline to
Audit status (completed on
Location of SVC Observations of the aduit and the name of audit agency
remove deficiencies as per
dd/mm/yyyy)
audit.
Maha
Guj
CG
MP
WR-I (PG) NA NA NA NA
WR-II (PG)
WR-I (NTPC)
WR-II (NTPC)
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131
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MSETCL
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Yashwantrao Mohite Krishna SSK
IPP Ltd., Not Integrated Yet Internet Leased Line (ILL)
MSETCL A A Energy, IPP Not Integrated Yet Internet Leased Line (ILL)
Baramati Agro Ltd, IPP Not Integrated Yet Internet Leased Line (ILL)
Daund Sugar Ltd., IPP Not Integrated Yet Internet Leased Line (ILL) Maharastra have informed that
JSW Steel Ltd., IPP Not Integrated Yet Internet Leased Line (ILL) they are taking up with IPP for
Shree Sidhbali Ispat Ltd, IPP Not Integrated Yet Internet Leased Line (ILL) integration
RPL Urja IPP Not Integrated Yet Internet Leased Line (ILL)
Lloyds Metal & Engineers Ltd.IPP Not Integrated Yet Internet Leased Line (ILL)
Siddhanath Sugar Mills Pvt. Ltd.,
IPP Not Integrated Yet Internet Leased Line (ILL)
M/s ISMT Ltd. IPP Not Integrated Yet Internet Leased Line (ILL)
M/s Shri Dudhganga VedgangaIPP Sahakari sakhar karkhana (SSK)Yet
Not Integrated Ltd. Internet Leased Line (ILL)
M/s Vasantrao Dada Patil Sahakari
IPP Sakhar Karkhana (SSK) Ltd.Yet
Not Integrated Internet Leased Line (ILL)
DATA INTERMITTENT
JAIGAD GS Data Intermittent
PARASEXTN GS Data Intermittent
TROMBAY GS Data Intermittent
DEEPNAGAR GCR GS Data Intermittent
BABLESHWAR2 400KV Data Intermittent
DEEPNAGAR 400KV Data Intermittent
DHULE 400KV Data Intermittent
KHAPARKHEDA 400KV Data Intermittent
KOLHAPUR3 400KV Data Intermittent
SOLAPUR3 400KV Data Intermittent
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Format-09
STATUS OF OPERATION OF POWER STATIONS UNDER FGMO/RGMO
Name of Region: Western Region
Remarks
Units
Units Units
Units required operating in Units
Total No. Units Total No. of Exempted applied to
co operate FGMO with operating Units whose
units/statio operating units under from CERC for especially
Description under manual with status is not
ns in the under FGMO/RG FGMO/ exemptio regarding
RGMO/FGMO intervention locked available
region RGMO MO (4+5) RGMO by n/ entries, if any, in
as per IEGC to archive governors
CERC extension column (9) or
RGMO
(10)
1 2 3 4 5 6 7 8 9 10 11
No of units (CS) 51 39 24 0 24 5 No info
No of units (SS) 255 139 44 23 67 8 No info
No of units (Pvt Sector) 114 87 35 8 43 0 No info
No. of stations (CS) 17 11 10 0 10 -- -- No info
No. of stations (SS) 84 41 16 9 25 -- 2 No info
No. of stations (Pvt Sector) 46 40 19 3 22 -- -- No info
Installed capacity CS (MW) 18210.67 12630 9320 0 9320 250 No info
Installed capacity SS (MW) 29943 22845 6870 850 7720 540 No info
Installed capacity PS (MW) 34573 28352 12537 4186 16723 0 No info
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Annexure-5.1.2
Protection Audit
Name of the utility: FY:
Whether Deficiencies No. of Deficiencies not yet
No. of Deficiencies No. of Deficiencies attended
identified for PA If identified for PA observed attended
Sr.
Name of the S/s kV PA if not done,
No. Category Category Category Category Category Category
Yes No conducted Target Date Yes No Total Total Total
A B A B A B
on date for PA
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Annexure - 6.1
Revised SPS of SR - NEW synchronization
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Annexure - 11
A meeting of group to review status of Protection Audit observations and discuss the recommendations of
the Task Force report was held on 18.12.2014. The list of participants is enclosed at Annex-I.
Shri S.D. Taksande, Member Secretary, WRPC welcomed the participants of the meeting. He
informed that in the 27th WRPC meeting the report & recommendations of the Task Force on Power
System Analysis under Contingencies (TFPSAC) headed by Shri V. Ramakrishna Ex. Member, CEA
were discussed summarily. The TFPSAC have recommended review of protection practices, system
studies for improvement of grid security and defined the scope of Protection Audit & Model setting
calculations for relay settings.
Since the recommendations are very exhaustive, WRPC decided that a separate group would be
formed to study the implementation of the recommendations of TFPSAC. Therefore this group would
review the existing protection relay setting practices, suggest as to how to go about carrying out system
studies to implement coordination of relay settings, PSS tuning activity and review the protection audit
observation status. The timelines for compliance of protection audit observations for Category- A and
Category-B as per the CERC order dated21.02.2014 have already over, the pending observations needs to
be rectified at the earliest. He hoped that the group would discuss all the recommendations and come out
with well-defined action plan for implementation of the same.
He requested Shri. Satyanarayan SE (P) WRPC to take up the agenda for discussion.
A-1) Status of compliance of the Protection Audit observations (Petition No. 220/MP/2012)
A-1.1. Background: CERC vide order dated 21.02.2014 in petition No. 220/MP/2012 filed by
POWERGRID have observed that “since the protection system is a vital requirement for the safe and
secure operation of the grid, we have decided that in order to implement the recommendations of the
Protection Audit, a compliance mechanism with definite time line needs to be put in place”.
Each SLDC shall be responsible to monitor the action taken by STU. If any deficiency in the
STU system in regard to the Category-A deficiencies is not corrected after 3 months of issue of this order,
the concerned SLDC may approach the respective State Commission for appropriate action against
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defaulting State entity in accordance with State Grid Code. The Office-in-Charge of the concerned SLDC
shall be responsible for monitoring and ensuring compliance of the action plan and filing of the petition as
directed herein.
RPCs at the end of each quarter shall prepare a report on the protection deficiencies and their
rectification which shall be sent to this Commission with a copy to CTU not later than 45 days of expiry
of the quarter. The Member Secretaries, Regional Power Committees shall continue monitoring the
protection related issues and bring to the notice of the Commission any instance of non-compliance of the
Regulation 1.5 of the Grid Code in respect of the protection related issues considered in the instant
petition.
The time lines for compliance of the above directives and submission of data to WRPC is as follows
The status as received from MSETCL as on Aug14, CSPTCL Aug 14, MP as on March 14 &
GETCO(All attended) as on March 14, has been filed with Hon’ble CERC vide letter Dtd. 26.09.2014
(Copy of which is available on WRPC web site). The data pertaining to ISGS, ISTS, Goa, DD & DNH is
not furnished by utilities to WRLDC and hence the same could not be filed with Hon’ble CERC.
A-1.2 : SE(P) stated that it is observed that the noncompliance of protection audit observations
submitted by Utilities enclosed at Annex.-A-1 were having certain recommendations of the
Protection Audit team which falls under the system improvement category and do not necessarily
pertain to protection deficiencies considered for audit. Hence this type of observations need not be
shown under the protection audit observations/recommendations (and needs to be removed from
the status to be filed with CERC). However these can be shown under the system improvement
recommendations category separately.
Constituents agreed to send the updated status by 31.12.2014. MSETCL have submitted the
updated status as above.
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PGCIL, GETCO and NTPC agreed to give the details of the Protection Audit observations as
above, though the observations have been attended by them.
It was also suggested that SLDCs shall monitor & submit the data for States and WRLDC shall
monitor & submit the data for central sector gen., IPPs and Powergrid.
In the 120th PCM, it was decided that utilities would submit data to nodal agency/officer and nodal
agency, after compiling the data may submit it to the WRPC for timely submission of the same to
CEA/MoP.
MP is regularly submitting the data. Other constituents were requested to submit the data
regularly.
It was decided that the status shall be submitted separately for protection audit carried out during
the financial year (i.e. FY 2012-13, 2013-14 and quarterly for April 14 on wards) in the formats
enclosed.
It was decided that a detailed status of all 132kV, 220kV, 400kV and 765kV Substations in the
enclosed format (detailed information of format 1 of annexure A-2.1) would be submitted within 10
days of issue of the MoM by all the utilities, as the same was not available with WRPC. The format
is enclosed at annexure – A.2.2.
It was agreed that SLDC and WRLDC would coordinate for the details of the statistics for the
formats.
CERC vide order dated 22.02.2014 in petition No. 167/Suo-Motu/2012, have directed to maintain the
relay settings data of all the ISTS lines and lines emanating from interface S/Ss of Utilities to ISTS. The
formats were enclosed at annexure – A.3 of the 122nd PCM Agenda. Data from MPPTCL is received.
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All the utilities agreed to submit the data in the enclosed format in fortnights time from issue of this
MoM.
First meeting of Grid Study Committee was held on 25.07.2014, wherein it was decided to carry out
protection audit at the S/Ss (other than already audited S/Ss) to be identified by the RPCs and submit
report to address gaps with reference to the recommendations of the task force.
It was decided that since utilities have agreed for submission of list of all S/Ss where protection
audit has been carried out and S/Ss where protection audit has not been carried out as discussed at
A-2. Based on this data the above can be validated in the ensuing PCM.
In 122nd PCM the report along with its recommendations were discussed. Also the issue pertaining to
oscillations observed in the grid under real time conditions was discussed following action plan was
recommended by PCM in line with the Ramakrishna Committee.
Various issues on the following recommendations were discussed during the meeting and the issues
involved and suggestions given are as follows;
a) ZONE-3 SETTING:
Back ground: The PCM reviewed the philosophy of protection and observed that the WR protection
settings are mostly in line with the recommendations. However issues pertaining to Zone-3 relay settings
& its coordination with the Lower voltage level protections would arise if the Ramakrishna Committee
recommendations (time grading & no compromise on the reach) are to be implemented. PCM felt that the
issue is of very complex nature, requiring tricky coordination and case to case consideration and requires
specialized study possibly involving consultants. However PCM observed that the existing Zone-3
settings in WR with DEF backup is found to operate satisfactorily since protection is not sacrificed.
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Hence switch over to the new philosophy (time grading & no compromise on the reach) may be done
only after adequate studies.
Suggestions: In built DEF protection of the DPS can be set for clearing the high resistance faults,
however this requires that the Z-3 time setting to be set between 1 sec to 1.5 sec. PGCIL
representative stated that the in built DEF can also clear highly resistive phase to Phase faults, since
it measures both Zero & negative sequence. It was suggested that Impedance relays on ICT can
address this issue in a more appropriate manner.
It was decided that this would be put up before the PCM for vetting/discussion.
b) ZONE-1 POWER SWING BLOCKING :Utilities in WR are following different practices in setting
the power swing blocking as follows;
(i) Blocking power swing for all zones for 2 secs and allow tripping in thereafter if swing remains in any
of the 3 zones.
(ii) Blocking of power swing in Z-2 & Z-3 and allow immediate tripping, if power swing enters in Z-1
characteristics of the relay.
(iii) Allow tripping in Z-3, Z-2 & Z-1 under power swing.
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the relay is allowed to trip. SE (P), WRPC pointed out that the power swing entering in Z-1 of DPS
is a serious system condition and the system would definitely fall out of synchronism under such
condition. Therefore tripping in Z-1 on power swing should be immediate.
It was pointed out that if immediate tripping is allowed under power swing in Z-1, the
system is allowed to separate nearly at 180 degrees apart. This would endanger the breakers
opening under such conditions, since the breakers may not be designed for opening a system which
is out of step. Therefore it would be appropriate to allow a time delay since it would at least ensure
that either the swing is recoverable or the delay would avert opening the breaker when the swing is
well past 180 degrees.
c) The PCM recommended that the protection audits in future shall be carried out as per the guidelines
and formats as given in the recommendations.
Suggestions:
The Task Force on Power System Analysis under Contingencies (TFPSAC) suggested relay setting
guidelines, proposer & validator system to ensure settings are implemented correctly and
protection audits to be carried out under the guidelines suggested by the committee. The group
discussed the issues and suggested following to be put to the PCM.
i) First party audit: Every S/s of 100 kV & above shall audit the settings in line with
recommendations of the above task force by the I/c of concerned S/s. Any issues pertaining to
settings shall be discussed in the utilities internal PCM or control relay management group of
utility and sorted out. Unsorted issues can be taken up in WRPC PCM if any. The frequency of
audit of first party shall be yearly once. Also any change in settings, this procedure of audit shall be
followed.
ii) Third party audit: Considering expertise available in all utilities, it was decided to form a
permanent panel of testing experts of all utilities of WR. Any utility seeking third party audit shall
form team of 3 members for audit, with two members (not belonging to to utility but from above
panel). Utility is also free to choose full third party from other agencies like CPRI. Guidelines for
frequency of 3rd party audit needs to be decided by PCM.
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2) Formulation of Special groups for studies and protection coordination: The above report mentions
the need to form specialized groups to carry out the system studies, protection, control and stability,
identification and training of man power, etc. PCM recommended that the existing study group and
protection groups would interact and come up with suggestions to implement the recommendation. PCM
recommended that a small group would assess the requirements in various areas and suggestions would
be examined in a special meeting.
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5) Following additional issues were raised by members as regards to recommendations of the Task
Force :
a) Zone-2 timings: The time setting adopted at present is 300 to 400msec. The Z-2 time setting
recommended is 350 msec, however for a long line followed by a short line higher setting of typically
600msec is recommended. The group suggested that in such cases the time setting to be adopted shall be
500msec, since 600msec time setting is too high.
b) Reverse Zone (z-4) S/S Local Backup Protection setting: The Task Force recommended that the Z-4
time delay would only need to coordinate with the BB main protection fault clearance and with Z-1 fault
clearance for lines out of the same S/S. For this reason this can be set according to the Z-2 time setting
guidelines. The group suggested that the time delay for Z-4 be set equal to Z-2 time+ 100msec, for proper
coordination with Z-2, instead of Z-2 time settings.
As regards to resistive reach for Z-4 the Task force recommended to keep it identical to Z-3 resistive
reach setting. The group suggested that the specific R/X ratio is required to be maintained in certain
relays, therefore while deciding the setting for these relays the R/X ratio should be maintained.
c) Main-I & Main-II DPS for 220kV Lines: For proper coordination the Main-I & Main-II relays on
220kV lines should be Distance relays in the new S/Ss and wherever the backup O/C E/F is used as Main-
II in the existing S/Ss shall be replaced with DPS in a phase manner.
SE (P), WRPC stated that outcome of deliberations shall be put to PCM, which will be scheduled in
January 2015. However other suggestions and recommendations of today’s meeting shall be followed by
constituents. .
*******************************************************
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Annexure - 12
1. DPR SETTING GUIDELINES FOR 400 KV LINES – DPR settings adopted by MPPTCL and PGCIL
400 kV transmission lines as well as settings recommended by CBIP, CEA and WRLDC are given below:-
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:2:
To minimize the fault clearing time in 3rd Zone, which is rare, the time setting adopted in MP
is 700 ms and the backup O/C, E/F setting kept beyond 700 ms - 1000 ms for other end bus
fault where bus protection is not provided whereas settings adopted by PGCIL are not consistent
with that of MPPTCL. Fault clearing time for both the ends should be same for reliable system
operation.
The matter was discussed in 466th OCC meeting and it was decided that the matter will be
discussed in the PCM for uniform standardization of time setting.
Report of the Task Force on Power System Analysis under contingencies headed by Shri V.
Ramakrishna regarding Zone-3 setting recommendation has been given.
Matter of inconsistency in Zone-3 time settings as above and recommendation given by Shri V.
Ramakrishna Committee and adopted by MPPTCL and PGCIL are different. Hence the issue may
please be discussed in next 123rd PCM meeting of WRPC to arrive at common consensus with
regard to DPR settings adopted by various transmission utilities of Western Region.
2. Alternative scheme to put Auto Reclosure (A/R) in service on the EHV lines
connecting to Generating Stations-
In most of the cases Auto Reclosure (A/R) on EHV lines connecting to Generating Stations
are kept out of service, to avoid charging of faulty lines from Generating Stations. Many times
tripping of these loaded lines on transient faults create emergencies regarding power evacuation,
power swings and system stability. That further resulted in to backing down of generation or other
operations to save the system. But all these exercise may take considerable time.
In general, most of the transient faults occurred are of single phase to ground in nature
and auto reclose of the line is the best option to maintain the reliability and stability of the system.
But a possibility of auto reclose attempt on a faulty line and its anticipated impacts always
discourage generating stations to put A/R in service, as they always prefer to synchronize a
healthy and charged line.
Therefore from generating station’s point of view, an auto reclose scheme can be
developed to reclose the line from generating station with some time lag i.e. about 400 msec. after
successful reclosing of line from the remote end and also on confirmation of healthy voltages on
line CVT at generating station end. This way problems related to switching on faulty line from
generating station can be overcome and system availability and stability could be maintained in
better way.
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:3:
The logic for this alternative scheme to put Auto Reclosure (A/R) in service on the EHV lines at
Generating Stations may be developed as following;
1 Keep dead time setting of A/R 900 ms at remote end from generating station.
2 Keep dead time setting of A/R 1300 ms at generating station and make AND logic of
reclose command with the line CVT voltages.
PGCIL has not provided Auto Reclosure facility at their end whereas State utility has
provided the same. Hence PGCIL may be advised to provide Auto Reclosure facility.
The matter is required to be discussed in PCM of WRPC to revise guidelines for providing
Auto Reclosure facility on EHV lines connecting Generating Stations and providing this facility by
PGCIL.
Thanking you,
Yours faithfully,
Encl: as above.
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