~~ qovernment of india - wrpcwrpc.gov.in/pcm/124_pcm_agenda.pdf · 2015-04-10 · agenda of 124....

~~qovernment of India~~~

Central Electricity Authority~~~~

Western Regional Power Committee~ -3, Q;ll'~ ~ 3fuft (~), ~ - 400 093

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

~ Phone: 022- 28209506, 28200195; 28200 196; ~ Fax: 022 - 28370193Website: www.wrpc.gov.in E-mail: [email protected]@gmail.com

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IS/ISO: 9001-2008

No.: WRPClProtection/124 PCMl2015/ Date: 10.04.2015

To

As per list,

Sub. : Agenda of 124th Protection Committee Meeting, WRPC - Reg.

Dear Sir / Madam,

Please find enclosed herewith Agenda of 124th Protection Committee Meeting of WRPC, to be held at

10:30 Hrs on 21.04.2015 at WRPC, Mumbai.

Agenda of 124th 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 constituents may come prepared (along with

presentation) for those major occurrences/disturbances under Item No.2.

Kindly make it convenient to attend the meeting.

Encl: As aboveY~tbfullY'

Satyanarayan. S,

Superintending Engineer (Protection)

HCL

Typewritten text

3353

Mailing list1 Chief Engineer (LD), MSETCL, Kalwa. Fax-27601769/652 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 /23462905 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 CE, SLDC, GETCO, Gotri, Vadodara

11 Chief Engineer (Gen), GSECL, H.O. Baroda. Fax-0265-5512129/2344537

12 S.E. (Testing), GETCO, Baroda. Fax-0265-2351218

13 Chief Engineer (LD), MPPTCL, Jabalpur, Fax - 0761- 2664343 / 2970119.

14 E.D. (T&C), MPPTCL, Jabalpur. Fax-0761-2702710

15 ED (Engg.) MPPGCL, Jabalpur Fax- 0761-2660063

16 Chief Engineer (LD), CSPTCL, Raipur. Fax-0771 - 2574174

17 C.E. (T&C), CSPTCL, Raipur.Fax-0771-2574749

18 EE (T), CSPGCL- Fax.No. 07789-226227

19 S.E. (T&C), CSPTCL, Bhilai. Fax.No. 0788 - 2281561

20 S.E. (T&C), CSPTCL, Raipur. Fax No.0771 – 2574749 / 2574458.

21 EE, Division VIII (MRT),Elect. Dept; Goa Fax 0832-2735124.

22 Supdt.Engr., Electricity Dept., DNH, Silvasa. Fax : 0260-2642338

23 Executive Engr., Electricity Dept. DD. Fax: 0260-2250889

24 D.G.M. (O.S. ),N.T.P.C., Mumbai, Fax- 28216692

25 DGM, NTPC WR – II, Raipur, Fax: 0771 - 2544550

26 D.G.M. (EM), KSTPS, NTPC, Korba Fax 07759-233088 (Tele fax: 232440) /237462

27 DGM (EMD), VSTPS, NTPC, Vindhyachal Fax-07805-247713 /247711

28 DGM (EM-I), NTPC, SIPAT Fax-07752-246506 (Tele fax: 246691)

29 AGM (O&M), KGPP, Adityanagar, Surat Fax 0261-2861428/2861433

30 Sr. Supdt. (EM), Gandhar, NTPC Fax-02642-87402 / 87450

31 DGM (O.S.), WRLDC, Mumbai Fax-28235434

32 DGM, WRTS-I, PGCIL, Nagpur, Fax- 0712- 2631051 / 641366

33 AGM, WRTS-II, PGCIL, Baroda Fax-0265-2480952 (Tele fax: 2487542)

34 AGM, O&M, WRTS – III, PGCIL, Raipur. Fax: 0771 - 2970450

35 SME (E), TAPS-3&4,Tarapur Fax 02525-282001/282073

36 Maintenance Superintendant, TAPS –1 & 2, Tarapur.Fax- 02525-282121

37 SME(E), NPCIL , Kakrapara Fax 02626-234266

38 GM (Maint.). TORRENT Power., Ahmedabad.Fax-079-27506679

39 AGM (QAIT), TPC, Trombay. Fax –022-66687088

40 Asst. VP, Dahanu TPS Fax- 952528-222576 / 222039

41 GM (O & M), Reliance Infrastructure Limited, Mumbai Fax-30094488

42 GM (Electrical), JPL, Raigarh, Fax. No. 7767-281995, 281993.

43 AGM (OS), NSPCL, New Delhi . Fax.No.011 26717381/26717363/26717366

44 Vice President, APL, Ahmedabad 079-25557176

45 GM, RGPPL, Anjanwel, Guhagar, Ratnagiri, Fax.No. 02359 241071

46 GM, JSW Energy Ltd., Jindal Mansion, Mumbai- Fax.No.022 23526400

47 GM, CGPL, Mundra Fax.No. 02838 661188

48 VP, EPTCL, Hazira, Surat, Gujarat Fax: 0261 - 6682747

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Agenda of 124th PCM to be held on 21st April, 2015

AGENDA FOR THE 124th PROTECTION COMMITTEE MEETING OF WRPC TO BE

HELD ON 21.04.2015 AT WRPC MUMBAI

ITEM NO.1: CONFIRMATION OF MINUTES OF 123rd PROTECTION COMMITTEE

MEETING

Minutes of 123rd PCM, held on 20.01.2015 & 21.01.2015 WRPC, Mumbai were circulated vide WRPC

letter No. WRPC/Protection/123 PCM/2015/2263 dated 27.02.2015.

1.A Comments were received from GETCO vide letter GujSLDC/CE/MIS/WRPC-123rd PCM-

MoM/110315 dated 11.03.2015. It proposed amendment in item no. 13.1 as follows.

1st line of Item 13.1, ‘13.01.2014’ to be read as ‘13.01.2015’ and in 3 / 4 & 10th lines ‘400 kV

Bhachau – Vadavi D/C’ to be read as ‘400 kV Bhachau – Versana D/C’

1.B Comments were received from GSECL vide email dated 26.03.2015 and proposed amendment in

item no. 2.5.a

Item 2.5.a in 1st line ‘MPPTCL representative’ to be read as ‘GSECL representative’

1.C Detailed comments were received from WRLDC vide letter WRLDC/MO-III/1658/2015/262 dated

26.03.2015 (enclosed at annexure – 1.C).

Committee may like to discuss and confirm the minutes of 123rd PCM.

ITEM No. 2: SYSTEM DISTURBANCES

2.1 Occurrence on 17.11.2014 at 220 kV Pedambe S/s: MSETCL intimated that on 17.11.2014 at 220

kV Pedambe S/s, while taking out the Generating unit – 10 was being backed down, when the

generation was about 4 MWs open command was given CB of unit – 10. Y ph pole of the CB failed to

open (due to jam in plunger of trip coil), LBB of the same has operated 19:45 Hrs. All elements

connected to that bus got tripped. The report received from MSETCL is enclosed at annexure – 2.1.

Committee may like to discuss.

2.2 Occurrence on 02.12.2014 at 220 kV Kanhan S/s: MSETCL intimated that on 02.12.2014 at 220

kV Kanhan S/s, while restoring 132 kV Kanhan – Upplawadi ckt, B ph isolator of Bus – I didn’t get

close properly. At 13:40 Hrs a manual attempt was made to close it with discharge rod, it create 132 kV

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bus fault at 220 kV Kanhan S/s. As the busbar protection was in blocking mode, all elements tripped

from remote end. The report received from MSETCL is enclosed at annexure – 2.2.


2.3 Occurrence on 06.12.2014 at 220 kV SWPC S/s: MSETCL intimated that on 06.12.2014 at 220

kV SWPC (Sai Wardha Power Company) S/s, while restoring SWPC – Warora – II, at 17:48 Hrs flash

over occurred on Y ph isolator of the same line. All elements connected to bus – II of SWPC S/s tripped.

The report received from MSETCL is enclosed at annexure – 2.3.


2.4 Occurrence on 08.12.2014 at 220 kV Wani S/s, Maharashtra: MSETCL intimated that on

08.12.2014 at 04:20 Hrs, B ph PT (SCT make) of 220 kV bus – I got burst and caught fire at 220 kV

Wani S/s. The busbar protection of bus – I has operated and led to selective tripping of feeders

connected to bus – I along with bus coupler.

Further it was intimated that it was suspected that failure of PT was due to insulation failure.

As the PT doesn’t have tanδ point, measurement of C and tanδ carried out through GST mode but the

results were too high and inconsistent. During this incidence total loss of load was 7.2 MWs for 20

mins. All elements were restored by 06:45 Hrs. The report received from MSETCL is enclosed at

annexure – 2.4.



kV Kanhan S/s, at 00:27 Hrs, R ph PT of 220 kV bus section – I failed and created bus fault. The

delayed busbar protection operation led to tripping of all connected elements on back up protection /

from remote end. The report received from MSETCL is enclosed at annexure – 2.5.


2.6 Occurrence on 18.12.2014 at 765/400 kV Aurangabad (PG) S/s: WRLDC intimated that 765/400

kV Aurangabad (PG) S/s has one and half breaker bus system. On 18.12.2014 at 765/400 kV

Aurangabad (PG) S/s, main breaker of 765 kV Aurangabad – Wardha was hand tripped for DGA of CT.

After 2 minutes B ph pole of tie breaker got burst and damaged Y ph pole. The tie CB was partially

closed and carrying full load current, led to its failure. It created bus fault on 765 kV bus – I and all

breakers connected to this bus tripped. During this 765 kV Aurangabad – Wardha – I, 765 kV

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Aurangabad – Dhule and line reactor of 765 kV Aurangabad – Padghe –II (it is connected as bus

reactor) tripped. The report received from WRLDC is enclosed at annexure – 2.6.

PGCIL may give the status of tie breaker availability and its healthiness for 765 kV

Aurangabad – Dhule & L/R of 765 kV Aurangabad – Padghe – II.


2.7 Occurrence on 24.12.2014 at 220 kV Paras S/s, Maharashtra: MSETCL intimated that on

24.12.2014 at 01:28 Hrs, Y ph PT (SCT make) of 16.5/220 kV, 315 MVA GT – II got burst and caught

fire at 220 kV Paras S/s. The GT – II tripped.

Further it was intimated that failure of PT might be due to insulation failure. As the PT

doesn’t have tanδ point, measurement of C and tanδ carried out through GST mode but the results were

too high and inconsistent. No conclusions were drawn. During this incidence total loss of generation

was 180 MWs. The report received from MSETCL is enclosed at annexure – 2.7.


2.8 Occurrence on 31.12.2014 at 400 kV Pithampura S/s: MPPTCL intimated that on 31.12.2014 at

10:03:16 Hrs at 400 kV Pithampura S/s, C Ph disc insulator of 400 kV Pithampura – Shinghaji (SSTPS)

– II got failed and the line tripped from both ends. Simultaneously 400 kV Pithampura – SSTPS – I also

tripped.

Further it was intimated that the fault was cleared in Zone –I from Pithampura end in 47.5

msec and no signal received at other end. The fault was cleared in Zone – III from SSTPS end in 781.4

msec. Due to delay in fault clearance from SSTPS end, the fault was fed through 400 kV Pithampura –

SSTPS – I and the line tripped from Pithampura end in Zone – III i.e. in 829.4 msec. During this

occurrence there was no loss of load or generation. Both lines were restored by 12:02 Hrs. The report

received from MPPTCL is enclosed at annexure – 2.8.

MPPTCL may explain the reason for non-receipt of DT at SSTPS end on 220 kV Pitampur –

SSTPS – II and reason for non-sensing of above fault in Zone – II at SSTPS end. It may also give the

status of A/R on Pithampura – SSTPS – I & II lines.


2.9 Insecure operation of gird on 31.12.2014 & 01.01.2015: WRLDC intimated that during night

hours of 31.12.2014 & early morning hours of 01.01.2015 it was raining in central Madhya Pradesh &

Vidarbha area of Maharashtra. 5000 MWs load crash occurred in WR. During this, Madhya Pradesh &

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Maharashtra each were under drawing around 500 MWs. Heavy voltage, high frequency & critical

loading on inter regional lines was observed.

It was also intimated that during this, frequency was more than 50.2 Hz for most of the time

and even touched 50.55 Hz. The high voltage was observed at many nodes in spite of taking reactors

into service & opening of EHV lines. During this incidence, several lines tripped on O/V and reduced

reliability of supply. The flow on 765 kV Gwalior – Agra D/C touched 1170 MWs/ckt. The report

received from WRLDC is enclosed at annexure – 2.9.


2.10 Occurrence on 01.01.2015 at 765/400 kV Sipat S/s: WRLDC intimated that on 01.01.2015 at

08:49 Hrs unit 4 (660 MWs) was synchronized with grid. At 09:13:58.993 Hrs, 765 kV Sipat – Bilaspur

– I was taken out and at that time generation on unit – 4 was 98 MWs. After this 7-8 kV voltage drop

was observed at Sipat & Bilaspur S/s. It was followed by fluctuation in generation of unit – 4 from 15 to

270 MWs and 10- 20 MWs fluctuation in other units of Sipat generating station. As the hunting was

growing in nature, an attempt was made to bring the turbine on hydraulic mode but meanwhile the unit

tripped on low forward power protection. After this, oscillations diminished. The report received from

WRLDC is enclosed at annexure – 2.10.


2.11 Occurrence on 06.01.2015 at 400 kV JPL Stage – II S/s: WRLDC intimated that on 06.01.2015

at 13:16 Hrs, at 400 kV JPL stage – II S/s, while isolating section B of 400 kV Bus – I, R ph flashover

was observed at sectionalizer and bus fault occurred on 400 kV bus I. As the busbar protection of Bus –

I failed to operate, fault was seen by remote ends. The 400 kV JPL – JPL Stage – II I/C tripped in 200

msec on U/V protection and 400 kV JPL Stage II – Tamnar (PG) – I & II tripped from remote end on R

ph E/F in Zone – II. It was also intimated that during this event, the line flows of 400 kV JPL – Raipur –

I & II increased. All elements were restored by 14:30 Hrs. The report received from WRLDC is

enclosed at annexure – 2.11.

M/s JPL may give the status of healthiness of busbar protection at JPL Satge – II and may

also give status of implementation of revised SPS.


2.12 Occurrence on 13.01.2015 at 220/132 kV Ponda S/s: WRLDC intimated that on 13.01.2015,

prior to the occurrence, Goa was meeting 285 MWs from WR and 100 MWs from SR (source feeders

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are 220 kV Mapusa – Ponda S/C & 220 kV Amona – Ponda T/C). At 16:10 Hrs, 220 kV Mapusa –

Ponda tripped on R Ph E/F. Simultaneously 220 kV Amona – Ponda T/C tripped on directional E/F and

220/132 kV Ponda S/s isolated from the grid & collapsed. The total loss of load during this event was

140 MWs. The 220 kV Amona – Ponda T/C restored by 18:10 Hrs of 13.01.2015 and 220 kV Mapusa –

Ponda restored by 13:28 Hrs of 14.01.2015. The report received from WRLDC is enclosed at annexure

– 2.12.

Goa Electricity Board (GEB) may give the details of tripping of 220 kV Amona–Ponda T/C.


2.13 Occurrence on 21.01.2015 at 220 kV Wanakbori S/s: GSECL intimated that on 21.01.2015

maintenance of 220 kV bus – II along with few feeders was planned. All the auxiliaries of bus – II were

transferred to 220 kV bus – I and bus – II was made dead. While the outage of 220 kV WTPS –

Dhansura – I was under progress, at 12:54 Hrs, earth rod of 220 kV WTPS – Dhansura – I was moved

by working personnel for providing earthing but it came into induction zone of live part of bus isolator.

A heavy sparking & big sphere of arc occurred. As the busbar protection was kept OFF during the

transfer of auxiliaries, all elements connected to bus – I tripped on back up protection along with unit 2,

3 & 7. During this event, 400/220 kV, 500 MVA ICT at WTPS tripped on OLTC Bucholtz relay

indication.

Further it was intimated that unit 7 was connected to 400 kV bus but due to maintenance of its

auxiliary transformer, its auxiliaries were fed through 220/6.6 kV ST – 4, which was tripped during

above occurrence. The turbine of unit – 7 tripped and resulted in unit – 7 tripping on reverse power

protection. The total loss of generation during this event was 567 MWs. All elements except ICT were

restored by 20:56 Hrs of 22.01.2015 and the ICT was restored by 17:19 Hrs of 23.01.2015 after oil

filtration & testing. The report received from GSECL/GETCO is enclosed at annexure – 2.13.


2.14 Occurrence on 23.01.2015 at 220/132 kV Damoh S/s, MP: WRLDC intimated that on

23.01.2015 at 220/132 kV Damoh S/s, at 11:27 Hrs R Ph CT (SCT make) of 220 kV Damoh – Katni got

burst at Damoh end and created 220 kV bus fault at Damoh S/s. Busbar protection operated and all

elements connected to this bus tripped. During this total loss of load was 14 MWs for 21 minutes. All

elements except 220 kV Damoh – Katni were restored by 12:15 Hrs and 220 kV Damoh – Katni

restored at 15:30 Hrs of 25.01.2015.

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It was also intimated that from EL it was observed that R Ph E/F occurred o 220 kV Damoh –

Katni at 0.02 Kms and A/R operated. It was followed by bursting of above CT. The report received from

WRLDC is enclosed at annexure – 2.14.


2.15 Occurrence on 27.01.2015 at 220 kV Ghatodi S/s: MSETCL intimated that on 27.01.2015 at

09:16 Hrs, at 220 kV Ghatodi S/s, CB of 220 kV Ghatodi – Pusad line was hand tripped, isolator was

opened and earth switch closed due to human error. The 220 kV Ghatodi – Pusad line tripped from

Pusad end on 3 Ph E/f. Simultaneously 220 kV Pusad – Yavatmal & 220 kV Pusad – Bhugaon lines

tripped from remote end on distance protection. Due to loss of 220 kV source feeders, 132 kV Patur load

was shifted to 132 kV Washim – Jambazar – Patur. 132 kV Washim was fed through 132 kV Chikali –

Mehkar – Malegaon – Washim & 132 kV Paras – Patur – Malegaon – Washim. The 132 kV Chikali –

Mehkar & 132 kV Patur – Malegaon tripped on back up & O/C protection respectively. During this

occurrence total loss of load was 225 MWs. All elements were restored by 12:47 hrs. The report

received from MSETCL is enclosed at annexure – 2.15.


2.16 Occurrence on 31.01.2015 at 220 kV Ghatodi S/s: MSETCL intimated that on 31.01.2015 at

11:31 Hrs, 220 kV Ghatodi – Pusad line tripped on R ph transient fault. A/R was successfully operated

at 220 kV Pusad end (in Zone - I) but line tripped from 220 kV Ghatodi end (in Zone - II).

Simultaneously 220 kV Ghatodi – Nanded line tripped from Nanded end in Zone – II.

It was also intimated that due to fault in DC – CPU the line didn’t auto reclose at Ghatod end

and got tripped. Further it was intimated that the 220 kV Ghatodi – Nanded line is a long line followed

by short line, its distance relay might have over reached. During this occurrence total loss of load was 44

MWs for 39 mins. All elements were restored by 12:10 hrs. The report received from MSETCL is



2.17 Occurrence on 08.02.2015 at 400 kV JP Nigrie S/s: WRLDC intimated that on 08.02.2015

at 18:31:55.759 Hrs 400 kV JP Nigrie – Satna D/C tripped on Y – B Ph – Ph fault. With the loss of

evacuation lines, the generating unit – I also tripped. During this event total loss of generation was 608

MWs. All elements were restored by 13:05 Hrs of 09.02.2015. The report received from WRLDC is


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2.18 Occurrence on 11.02.2015 at 400 kV Satpura S/s: MPPGCL intimated that on 11.02.2015 heavy

rains observed at 400 kV Satpura S/s. At 00:20 Hrs, B-phase CT of unit – 8 got damaged. The unit – 8

tripped on class ‘A’ protection with E/F, O/A differential protection & REF protection indications.

During this event, the total loss of generation was 5665.7 MWHs. The unit was synchronized at 09:05

Hrs on 12.02.2015 after replacing the faulty CT. The report received from MPPGCL is enclosed at

annexure – 2.18.


2.19 Occurrence on 13.02.2015 at 400 kV GMR EMCO S/s: GMR EMCO intimated that on

13.02.2015 at 16:32 Hrs, GMR EMCO line II tripped on B ph to E/F in Zone - I. During this GMR

EMCO unit – II also tripped due to turbine trip. The total loss of generation during this event was 0.98

MUs. The line was restored at 19:13 Hrs. The report received from GMR – EMCO is enclosed at

annexure – 2.19.

M/s GMR may provide complete details of the event.



kV Kanhan S/s, at 05:30 Hrs, B ph CT of 220 kV Kanhan – Suryalaxmi feeder got burst due to

insulation failure and created bus fault. All elements connected to this bus tripped on busbar protection

operation. The report received from MSETCL is enclosed at annexure – 2.20.


2.21 Occurrence on 23.02.2015 at 220 kV GCR Eklahare S/s: MSETCL intimated that on 23.02.2015

at 220 kV GCR Eklahare S/s at 18:15 Hrs, B ph CT of 220 kV bus section I got burst due to thermal run

away of insulation (tanδ results found to be in order) and caused bus fault in 220 kV busbar Zone -A.

Busbar protection of Zone – A operated and tripped all elements connected in this zone along with

generating unit - 3. During this, due to failure of auxiliary supply, unit – 5 also tripped. The total loss of

generation during this incident was 290 MWs. The report received from MSETCL is enclosed at

annexure – 2.21.


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ITEM NO. 3: Tripping of lines / ICTs: The minor incidences of tripping of lines and ICTs during the

period 01-12-2014 to 28-02-2015 are enclosed at Annexure–3.

In the 121st, 122nd & 123rd PCMs, Committee suggested that the utilities may indicate whether

A/R is provided on the lines and whether the A/R operation was successful for transient faults and

locked out for permanent faults, for the lines in their system. Constituents are requested to provide A/R

availability/status for each line.


ITEM No. 4: Any other item

ITEM NO. 5: Date and Venue of the next meeting

Sub-Committee may decide the tentative date and venue for the next (125th) PCM.

******

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HCL

Typewritten text

Annexure - 1.C

Comments from WRLDC on 123rd PCM minutes

1. 2.2 Occurrence on 04.09.2014 at 220/66 kV Magarwada S/s, DD: “Committee observed thatthe above tripping was in order. However PGCIL was requested to give details of trippings /DRs for such incidents in future.”

Comments:

Here PGCIL as well as DD both have not submitted the DR files. So may include nameof both agency.

In addition, the mandatory provision of Auto-reclosure on 220 kV lines as per CEATechnical standards for construction of electric plants and electric lines –Clause43(4) (c) has been missed which was quoted during the discussion. It was observedthat A/R has not occurred on 220 kV Vapi (PG)-Magarwada 1 circuit.

2. 2.4 Occurrence on 05 & 06.09.2014 at 400 kV APL, Mundra S/s: “It was intimated that theinference of observation of SSR phenomena by WRLDC needs to be confirmed after detailedinspection of data acquired during the above occurrences since the SSR can’t be fullycaptured through PMU data.”

Comments:The SSR phenomenon frequency range is 10-40 Hz. The PMU data can not exactly give thesefrequencies as per NY quest criteria. It is well established that when any oscillatoryfrequency whose frequency is more than NY quest frequency of the reporting/samplingdevice, it will be appear as wrapped frequency. The details for the above phenomenonobserved from PMU were also shared in the 30 May 2014 report of SSR at APL Mundra,which may be relooked. Further, the inferences were not only driven from the PMU data butalso from the SSR damping controller activation SOE at HVDC Mundra, which has beenattached in the report.

3. 2.5.b Occurrence on 10.09.2014 at 400 kV Indore S/s:

Comments:

This incident was serious in the view that SCADA data to WRLDC for MPPTCL andISGS station in the area along with PMU data of Vindhyachal, Bina (MP), and Itarsiwas lost. MPPTCL /MP SLDC have not yet submitted the report for the failure andreason for failure of SCADA data.

4. 2.8 Occurrence on 17.09.2014 at 400 kV JP Nigrie S/s:Comments:

JP Nigrie is an IPP of Western Region and it comes directly under WRLDC ControlArea. The Name of MPPTCL has been quoted for coordination, which may kindly beremoved.

Further WRLDC has already requested for taking A/R of these lines in service. Thesame has been mentioned in WRLDC Report. As protection come under the RPC asper the regulations, so WRPC is kindly requested to take up the matter with JPNigrie.

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5. 2.11 Voltage fluctuations in WR on 21.09.2014: “Committee observed that the MVArabsorption fluctuations in the range of 8 to 55 MVAr at Mauda station may not have such animpact on bus voltages of Bhadrawati since the fault level of Bhadrawati is quite high.Therefore committee requested WRLDC to reexamine the reason for the fluctuations inVoltage and share the same with PCM”

Comments:

The analysis of any event can only be completed after the utility (NTPC) hassubmitted the complete information’s to WRLDC/WRPC. In the above event, NTPCwas requested several times to submit the information regarding the Mouda unitsfrom Generating Station DAS/SCADA in high-resolution format (1-second data) alongwith the event logger, which was not submitted. The Phenomenon was a dynamicphenomenon and SCADA send data at 4-15 second interval, which has given thedetails that MVAR variation in unit was around 50 MVAr, which may be quite largeas observed in various oscillation phenomenon from the PMU data and alreadyshared with the PCM committee. In view of this NTPC may be asked to share therequired data for analysis of the event.

Further, a similar incidence has been reported globally which has been given inWRLDC report on the event shared with the WRPC. The incidence has very highsimilarity with the above incidence and may be relooked.

6. 2.13 Occurrence on 26.09.2014 at 400 kV Waluj (Aurangabad) S/s:Comments:

In the above incidence, the primary reason behind the tripping was the non-compliance of CEA Grid standard 2010 that states that system should be within safeoperating margin with loss of one elements.

Committee also discussed regarding the poor distribution system in theMaharashtra system causing unsafe operation in real time. The need ofstrengthening of 220 kV distribution system may kindly be mentioned in theminute as it is missing.

7. 2.13.b Occurrence on 27.09.2014 at 220 kV Khaperkheda S/s:Comments:

In the above incidence, the primary reason behind the tripping was the non-compliance of CEA Grid standard 2010 that states that system should be within safeoperating margin with loss of one elements.

Committee also discussed regarding the poor distribution system in the Maharashtrasystem causing unsafe operation in real time. The need of strengthening of 220 kVdistribution system may kindly be mentioned in the minutes, which is not included.

This N-1 stability criteria non-compliance in 220 kV system of Maharashtra needsto be highlighted in the minutes, which helps in taking up the issues with MSETCL.It may be noted that on 7th May 2014, one 220 kV line tripping led to cascadedtripping in Pune ring main and its blackout. May include these in the minute.

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8. 2.15 Occurrence on 01.10.2014 at 400/220 kV Padghe S/s:Comments:

One of the important issue which was flagged in the meeting was impact of three-phase fault near to load centre that has been missed in the committee discussion. Itmay be noted that three-phase fault near to a load center is very severe in natureand this results in lots of operational challenge. Significant amount of research arebeing carried out at international level on the subject matter as such faults results inlarge loss of load at distribution level due to sever voltage dip and also it may resultin fault induced delayed voltage recovery (FIDVR) which operator in real time arenot able to comprehend. NERC has prepared a good white paper on the subjectmatter.http:// www.nerc.com/docs/pc/tis/FIDVR_Tech_Ref%20V1-2_PC_Approved.pdf

It may brought to the notice that load loss due to any event does not only meanthe load which are lost due to loss of a sub-station causing blackout , loss of radialline, load trimming scheme , SPS operation etc. It is accessed as the loss of load thatthat may be at transmission or distribution level or staggered. The above case is aspecial case of load loss that needs proper justification. The severity of three-phasefault seen by the fact that it results in such large dip in voltage causing loss ofvarious induction motor load at distribution level. This results in tripping of loads atdistribution level and was observed once again on a three phase fault on 220 kVKalwa-Colorchem circuit on 29th November 2014 where also similar load loss wasobserved.

The load loss accessed by WRLDC is based on the three facts:

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1. SCADA data of Maharashtra Demand: After the event Maharashtra demandreduced by a quantum of 1050 MW. (Figure given above and was given in theWRLDC Report on the above tripping)

2. SCADA data of Maharashtra Deviation from ISTS points : Maharashtra drawalfrom the grid reduced by 1039 MW. (Figure given above and was given in theWRLDC Report on the above tripping)

3. Frequency of Indian grid: Frequency rose just after the three-phase fault 0.167Hz. While taking a power number of 6000 MW/Hz for Indian grid, (This has beencomputed on several events reported earlier) gives a load loss of 1000 MW.(time duration of rise in frequency took 16 second)

Therefore, it may be seen that the loss of load was not only computed just on thefact of power number or Maharashtra demand or ICTs loading but also on theMaharashtra drawal from ISTS point that is used for operational purpose.

Here the basis of large load loss if based on time synchronized PMU data fromseveral number of PMU in Western region that clearly illustrate that frequencystarted rising just after the Three phase fault only which is the second event (Therewere 5 events during this grid incidence). As per Maharashtra report, loss of loadhas occurred during event 4, which occurred after few seconds of event 2 of three-phase fault and does not deal with the rising frequency just after the event 2. Forthis event in Indian grid was checked and only major event during the period was atPadghe. (For same WRLDC report may be once again reviewed which is preparedafter a thorough analysis of details provided by MSETCL)

Further the above issues on three phase fault at load centre sub-stations has beenprovided to CEA and CTU vide NLDC operational feedback on transmissionconstraints January 2015 available at POSOCO Website.

Further, even after communication Maharashtra SLDC has not provided the detailson the Load loss after clarifying the cause of load loss during this event and oneother event at Kalwa on 29th November 2014.

So accordingly, comment on load loss computation methodology may be modified.The WRLDC representative in the meeting also has highlighted the issue of three-phase fault and its impact on the grid, which may also be included for benefit ofmembers.

9. 2.20 Occurrence on 12.10.2014 at 400/220 kV Kalwa S/s:Comments:

In this case, second fault could have been prevented in the system if the 220 kVLines from major stations Kalwa is having provision of direct trip sending toremote end after Bus bar protection operation.

10. 2.21 Occurrence on 13.10.2014 at 765/400 kV Raipur Pooling Station:Comments:

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Instead of Raipur PS (Durg), the Raipur station need split bus arrangement forreduction in fault level.

11. 4.1: Compliance Status observations made in Protection Audit (Petition No. 220/MP/2012) WRLDC was requested to collect the details from ISGS, Goa, DD and DNH and in view

of that WRLDC has communicated to NTPC, NPCIL, NSPCL, NCA, Goa, DD and DNHfor submission of details on three occasions. In the comment sheet, ISTS datacollection responsibility has also been mentioned under WRLDC, which may be atyping error, and the same may kindly be omitted.

12. Item No 6: Commissioning of new system protection schemes in connection withsynchronization of SR and NEW grid

“Lanco-Amarkantak” may be replaced with “LANCO-Pathadi”

13. Item No. 11: Report of the Task Force on Power System Analysis Under Contingencies: It is mentioned that WRLDC should submit the details of PSS data of Generator ISGS

and IPP in enclosed format. The format is missing from the minutes and agenda. Thesame kindly be forwarded.

14. 13.1 Review of SPS at CGPL :Mundra, UMPP: In the meeting, WRLDC, GETCO and CGPL all were requested to convene ameeting among themselves for the revision of SPS. Inadvertently WRLDC and CGPL name hasbeen missed.

15. In annexure: On page 129 where SPS details in WR are given, Inadvertently in WR-SR SPS 5 ,it is mentioned that “800 MW Backing of Generation in WR ( JPL, JPL Extension, KSK, DBPower, LANCO, KWPCL, BALCO, NSPCL) and 500 MW load Shedding in SR Grid” which maybe replaced with “800 MW Backing of Generation in WR (Tiroda-200MW,Mauda-100MW,Koradi-70MW,Khaperkhada-150MW,Chandrapur-250MW Indiabulls-30MW) and500 MW load Shedding in SR Grid “. The corrected copy of SPS details send by WRLDCearlier is also attached for kind reference.

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Outage was availed on 132kV Kanhan-Uppalwadi ckt. During restoration of the ckt after outage , Bus-I isolator B ph Uppalwadi feeder did not closed properly; an attempt was made to close it manually/ forcefully with discharged rod, which created a busfault. ABB make RADSS Busbar scheme failed to operate, resulting in tripping of remote end. On investigation Bus bar scheme found in Block mode.

Trip Z2

Railway TSS-I Pench Mouda Uppalwadiunder outage

TSS-II Pardi (Nagpur-II)

Bhandara Mansar

200MVA,220/132KVICT-I

200MVA,220/132KVICT-II

132KV Bus-I

132KV Bus-II

Bus couplerHigh SETTRIP

Breaker ON

Breaker OFF

132/33KVT/F - I 132/33KV

T/F - II132/11 KV T/F- I

132/11 KV T/F- II

220KV Bus

Isolator closedT/F parallel

33KV Bus

Trip LV B/Up

Open Trip Z2

Fault 29A

HV B/Up

Occurence at 220KV Kanhan S/Stn on dtd. 02.12.2014

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On dtd. 06.12.2014, outage was availed on 220KV Warora line-II, during restoration work at 17:48 Hrs, flashover occurred on ‘Y’ ph isolator of 220KVwarora line-II, resulting in tripping of feeders connected to Bus-II at M/s SWPL end.

Bus I

Bus II

GT-1 GT-2 ST-1 Line 1

Bus Coupler

BreakerON

BreakerOff

SLD for Bus fault at SWPL

Line 2 ST-2 GT-3 GT-418

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MAHARASHTRA STATE ELECTRICITY TRANSMISSION COMPANY LIMITED

Ref. No.: - MSETCL/SE/T&C/Circle/AKL/Tech/ 0355 Date: 08.12.2014

Sub: - Occurrence dated 08.12.2014 at 220 KV Wani substation – Analysis thereof.

Ref: - EE/EHV/O&M/Dn./Amt/Tech/3872 Date: 8.12.2014

A) Occurrence: -

The B phase PT of 220 KV Bus-I at 220 KV Wani substation burst and caught fire on08.12.2014. at 04:20 hrs. The bus bar protection operated and selective tripping of all the 220 KVfeeders connected to Bus-I occurred. The details of the occurrence are shown in the table below:

Slno.

Name ofthe

substation

Name of thebay tripped

due tooperation ofbus bar relay

Date andtime of the

tripping

Date andtime of

restoration

Relayindications

Remark

1.

220 KVWaniS/stn

220kV Bus barpanel08.12.2014– 04:20hrs

08.12.14–06:15 hrs

REB 500Bus BarPanel87BBBus BaroperatedBussection Ioperated

Tripped onoperation ofbus barprotection relay(REB 500) dueto failure ofB-phase PT-Iof 220 KV BusSection I.Area fed by 3nos of 33 KVfeedersaffected for 20min.(load affected7.20 MW)

2.220kV Wani-ChandrapurLine

08.12.2014– 04:20hrs

08.12.14–06:45 hrs

96- BusBar relayoperatedREC 670 –Start(Zone-4)3. 220/33kV25MVA T/F-I 08.12.2014

– 04:20hrs08.12.14–06:25 hrs

96- BusBar relayoperatedThe single line diagram showing details of the occurrence is enclosed herewith.

B) Investigation/Analysis:1. The PT is suspected to have failed due to insulation failure.2. Due to failure of B ph PT I of 220 KV Bus Section I at 220KV Wani S/Stn., it causes the busfault on section I of 220 KV Bus. The operation of Bus bar is in order. As 220 KV Wani -

From,Office of The Superintending Engineer,Testing & Communication Circle,3rd Floor, Vidyut Bhawan,Ratanlal Plot, Akola.Tele : 0724-2426870Fax : 0724-2421660Email : [email protected]

[email protected]

To,The Chief Engineer,EHV CC O&M ZoneMSETCL, Amravati.

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Annexure - 2.4

Chandrapur line and 220/33 KV TF I are on same bus section, the tripping of the said line & TFis correct and in order. Also the tripping of Bus sectionalizer on BB is in order as it saved theother half Bus Section.3. This PT does not have the tan delta point. The measurement of C and tan delta on GST modewas carried out but the test results obtained were erratic, means the results were too high andinconsistent. The results, therefore, were not conclusive.4. Details of failed PT: Make – S.C.T. Gaziabad, Rated voltage- 245kV, Sr. No. - 2286/08, Yr ofMfg.- 2008, Commissioning date – 10.06.2010.

C) Area affected:Area fed from 33 KV feeders connected to the LV of TF I are affected for 20 min. Load

Before trip 7.2 MW.

D) Remedial measures:1) 33 KV side feeders are restored at 4:40 hrs by shifting load on 220/33 KV,50 MVA TF II.2) After extinguishing fire & isolating burst PT. The PT supply of Bus-2 PT is extended to

affected feeders and the supply is restored.3) The faulty PT has being replaced shortly by new PT.4) The failure of PT in short span is not desirable. Hence matter should be referred to themanufacturer. The SCT make PT’s are not having Tan Delta point and gives erratic Tan Deltaresults in GST mode. Also the pre-commissioning Tan Delta results are not available. Hence thehealthiness 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 beexplored, so that testing can be carried out to ensure the healthiness of PT.

Submitted please.

Encl: Single line diagram

Sd/-SUPERINTENDING ENGINEER

TESTING & COMMUNICATION CIRCLEMSETCL, AKOLA

Copy s.w.r.to:1) The Chief Engineer, Trans (O&M), C.O., MSETCL, Mumbai.2) The Chief Engineer, SLDC, Kalwa.

Copy f.w.c.to:1) The Superintending Engineer, Trans O&M Circle, Amravati.2) The Superintending Engineer, LD Centre, Ambazari.

Copy to:1) The Executive Engineer, Testing Division, MSETCL, Yavatmal.

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B Phase PT-I ofbus section failed

Occurrence of Busbar on dated 08.12.2014 at 220 KV Wani S/Stn.SSubstation.

220 KV Warora Line220 KV MainBus Section I

220/33 KV. 50 MVA, T/F-II220/33 KV. 25 MVA, T/F-I33 KV Bus

CB OpenCB TrippedCB (Not Tripped)

CB Open

PT-I220 KV Chandrapur Line

220 KV Bussectionalizer C.B.

33 KVRPL Urja 33 KVKolarPimpri 33 KVRajur 33 KVLalgadiFeeders affected for 20 Min(Load 7.2 MW)

33 KVLalguda I 33 KVCottonMarket 33 KVShindola

220 KV MainBus Section II

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220kV R ph Bus PT of bus section-I failed, resulting in delayed operation of ABB make RADSS Bus bar scheme, leading to tripping of all feeders connected to Bus-I alongwith with some feeders from remote end

220 KV Kanhan Bus

132KV Kanhan Bus

132KVmauda

220KV Virangana

220KVSuryalaxmi

220KVKhaperkheda

220KVUmred

132KV Pardi132KVUppalwadi





220KV Bhandara

Breaker ON

Breaker Trip

SLD for Bus fault at 220KV Kanhan S/Stn on dtd. 17.12.2014

Fault

132KV BhandaraBus

220 KV Kanhan Bus

132KV Kanhan Bus

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Grid Incidence at 765/400 kV Aurangabad (PG) Sub-station on 18th December 2014

Event Category: GI-2

Event Date and Time: 18th December 2014, 17:19 Hrs

Event Summary: At 17:19 Hrs , B Phase pole of Tie Breaker of 765 kV Wardha-Aurangabad 1 line atAurangabad sub-station burst leading to Bus fault on 765 kV Bus 1 at Aurangabad. This led to Bus barprotection operation and all breakers connected to Bus 1 tripped. During the event 765 KVAurangabad-Wardha-1, 765 kV Aurangabad-Dhule and L/R of Aurangabad-Padhge 2 (Connected asBus reactor) have also tripped from Aurangabad.

Figure 1 : Geographical Map

Event Overview: Prior to the event , 765 kv Auranagabad-Wardha 1 line Main bay maintenance work was

being done at 765/400/220 kV Aurangabad sub-station. For taking CT oil DGA of Main-bay of this line, Main breaker was hand tripped and bus side

isolators were opened. After 2 minutes of opening of main breaker, tie breaker B-Pole(Master pole) blasted. This has also caused chipping of 3-4 petticoats of column &interrupter of Y-Pole. The failed circuit breaker is of Siemens make. On investigation, it was foundthat the locking pin between operating rod and drive rod is missing in this pole. This had resultedin partial closing of the breaker contact, which with the opening of main breakerexperienced total load current causing its failure.

The fault has led to Bus Fault on 765 kV Bus 1 of Aurangabad as the Main bay for Bus 1 in the samediameter has not been commissioned. This led to Bus bar protection operation for Bus1 and all main breakers connected with Bus 2 tripped.

It was observed that with the opening of all main breakers of 765 kV Bus 1, 765 kV Wardha-Auranagabad 1, 765 kV Aurangabad-Dhule and L/R of Aurangabad-Padhge 2 (Connected as Busreactor) have tripped.

The tripping of 765 kV Aurangabad-Dhule and L/R of Aurangabad-Padhge 2 indicates that thetie circuit breaker for these elements has not been commissioned or was kept open. WRLDC hasnot issues any code for opening of these breakers, which indicate that these have so far notbeen commissioned.

Table 1 : Sequence of events

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Elements TrippingTime

Relay Indication atEnd 1

Relay indication atEnd 2

RestorationTime

765 kV Bus 1 Aurangabad 17:18:59.800Bus Bar protectionoperated -

765 kV Wardha-Aurangabad 1 17:18:59.800 Bus Bar protection

operated Not available

L/R of Aurangabad-Padhge 2 ( Charged as Busreactor)

17:18:59.800Bus Bar protectionoperated -

765 kV Aurangabad-Dhule 17:18:59.800Bus Bar protectionoperated Not available

* Based on WRLDC SCADA SOE/PMU

Protection and Operation Related Issues:

The multiple tripping in the 765 kV one and half breaker scheme is of serious concern. This is anon-compliance of regulations of CEA, which are CEA Technical Standard forConstruction of Electrical Plants and Electric Lines: 43.4 .A and CEA (Technical standards forconnectivity to the Grid) Regulation, 2007: Schedule Part 1. (6.1, 6.2, 6.3).

The one and half breaker scheme purpose is to restrict one element tripping in case of mainbreaker/main bay CT failure and two elements tripping in case of tie breaker/Tie bay CT failure.While in above case apart from the element that should have tripped during the fault as per thefault and associated protection operation, other elements have also tripped.

This is indicative that either the protection scheme is wrong or the Tie CB of the of 765 kVAurangabad-Dhule and L/R of Aurangabad-Padhge 2 are not commissioned (incomplete diameter)or these circuit breakers are kept open without any intimation to WRLDC.

There have been few cases earlier where the new elements are being commissioned withoutcompletion of the diameter resulting in inadequate reliability pertaining to these elements. Evenduring few emergency outage of main bay it was found that element(Line/ICT) will also trip afterallowing the outage as the corresponding Tie bay/CB is not yet commissioned. Such incompletediameter act as a surprise to WRLDC/NLDC system operator as it is thought that element shouldnot have tripped but in actuality, it has tripped. This result in lots of challenge during realtime system operation.

In view of this, all the new elements should come in service with both main as well as tie baycompletion (Tie bay should either be connected directly to other bus if the other main bay is notin service in the dia or through the main bay of other element).

The same has been given as a feedback to CEA and CTU in the Operational Feedback onTransmission constraint January 2015 on page 66: “It has been observed that in many of the newsub-station, the tie breakers in one-half scheme of new elements are not yet commissioned whichhas resulted in various constraint as tripping/outage of main breaker results in outage of theelements. In few cases, it has been observed that after a long delay also the Tie CB are notcommissioned which has resulted in real time constraint as in case of Bus bar protection or LBBprotection operation, these elements get tripped. Therefore, any elements, which should becommissioned in future, should come with Main and Tie CB simultaneously or the tie CBshould be commissioned within one months of the Main CB and associated Transmission elementcommissioning on priority basis.”

Further it was observed that after bus bar protection operation, the voltage was stillobserved in the 765 kV Wardha-Auranagabad 1 DR (Figure 2) from Aurangabad end in R and YPhase which indicate that Line has tripped in Single phase to earth fault from the remote endrather than on direct trip after the Bus bar protection operation for the 765 kV circuit and 765kV Main Bus 1. The other two phases have tripped from remote end (Wardha) after around 1.2seconds as seen in below figure.

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Figure 2: Voltage plot from DR of 765 kV Wardha-Aurangabad 1 from Aurangabad end.

Further it can be seen from voltage plot of Bhadrawati PMU(figure 3) that two faults hasbeen observed, where the first one coincide with time of fault as per SOE of Aurangabad whilethe next fault has occurred after 1.28 second after it. This suggest that 765 kV Wardha–Aurangabad 1 has attempted autoreclosure from Wardha end which can also be seen from thedeveloping voltage in B Phase as shown in figure 2 .

Figure 3: Voltage plot from Bhadarwati PMU indicating two faults in an interval of around 1.280second indicating a possibility of auto reclosure.

This give evidence that the bus bar protection at Aurangabad end has not yet beenfully commissioned which is very serious in view of grid operation.

Further it may be noted that, the 765/400 kV ICTs at Aurangabad were onlyconnected with their Main CB only due to absence of Tie CB which has endangeredthe grid security.

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Ref. No.: - MSETCL/SE/T&C/Circle/AKL/Tech/ 0374 Date: 24.12.2014

Sub: - Occurrence dated 24.12.2014 at 220 KV Paras substation – Analysis thereof.A) Occurrence details: The HV side Y phase metering PT of 16.5/220 KV, 315 MVA GT-2 at 220 KV

Paras substation burst and caught fire on 24.12.2014. at 01.28 hrs. The 220 KV CBs of GT-2 tripped. The details ofthe occurrence are shown in the table below:

Slno.

Name ofthe

substation

Name of thebay tripped

Date andtime of the

tripping

Window & Relay indications Remark

1.220 KV

ParasS/stn

16.5/220 KV,315 MVA

GT-2

24.12.2014– 01:28hrs

At 220KV Paras end :W/I – Master trip relay.At Genco end :W/I --1) Generation protectionrelay operated.2) Generation Ckt trip relayoperated.3) US,2C,2D,2A,2B,undervoltage.4) Generation protectionelectrical operated.5) Generation protectionelectrical Trip.R/I: - 186A,186A1X,286A,286A1X operated

GT-2 Trippedon failure ofY-phasemetering PT

B) Investigation/Analysis:1. The PT is suspected to have failed due to insulation failure.2. This PT does not have the tan delta point. The measurement of C and tan delta on GST mode wascarried out but the test results obtained were erratic, means the results were too high and inconsistent.The results, therefore, were not conclusive.3. Details of failed PT: Make – S.C.T. Gaziabad, Rated voltage- 245kV, Sr.No. - 44/09,Year of Mfg. 2009, Commissioning date – 17.11.2009.C) Area affected: - Area affected – Nil.D) Generation affected: - GT-2 - 180 MW

. E) Remedial measures:1) The faulty PT has being replaced shortly by new PT.2) The failure of PT in short span is not desirable. Hence matter should be referred to themanufacturer. The SCT make PT’s are not having Tan Delta point and gives erratic Tan Delta resultsin GST mode. Hence the healthiness of PT cannot be ascertained due to unavailability of testingresults. It is suggested that while procuring PT, the availability of Tan Delta point may please beexplored, so that testing can be carried out to ensure the healthiness of PT.




[email protected]


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Single Line Diagram of 220 KV Paras S/Stn. (Ref-Occurrence dated 24.12.2014 )

CB Not TrippedCB TrippedCB Already Open

TransferBus

Main bus-II

Main bus-IGen.T/F-2

Gen. T/F-1 StationT/F-2Chikhali-2Akola-2 Balapur-3 Balapur-2

Y Phase PT(Metering)failedAkola-1 Chikhali-1 Balapur-1 Balapur-4

Bus Coupler

StationT/F 1

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Pre-Fault ConditionOn dated 31.12.14 at around 10:00 Hrs. MP System was normal and frequency of National Grid was

49.84 HZ.

At 400 S/s Pithampur all 400 KV & 220 KV feeders were in charged codition and normally loaded.

Feeder arrangement at 400 KV S/s Pithampur prior to fault was (‘+ive’ export & ‘-ive’ import):-

S.No. On 400 KV Main Bus – IMWLoading S.No. On 220 KV Main Bus – II

MWLoading

1. 400 KV Pithampur – SSTPS Ckt – I 101 1. 400 KV Pithampur – SSTPS Ckt – II 101

2.400 KV Pithampur – Indore (PGCIL)Ckt – I

-291 2.400 KV Pithampur – Indore (PGCIL)Ckt – II

-291

3. 400/220 KV, 315 MVA X’mer – I 188 3. 400/220 KV, 315 MVA X’mer – II 188

Occurrence

At 10:03:16 Hrs. ‘C’-Phase Disk Insulators at location No – 6 of 400 KV Pithampur – SSTPS Ckt – IIfailed resulting in tripping of the circuit from both ends. Simultaneously 400 KV Pithampur – SSTPS Ckt – Ialso tripped from both ends. The relay indications of both end were as follows:-

S.No. Name of Feeder/transformer Tripping EndTrippingTime (as perSOE)

Indication

1.400 KV Pithampur – SSTPSCkt – II

Both End10:03:14.322Hrs.

Pithampur end:- DPRoptd., Zone-I, Phase-B,NG, Dist-2.31 Km.SSTPS end:- Zone-III,Phase-B, Dist-119 Km.

2.400 KV Pithampur – SSTPSCkt – I

Both End10:03:15.094Hrs.

Pithampur end:- DPRoptd., Zone-III, Dist-221.7 Km, O/V, STG –I optd, Phase-B, NG.SSTPS end:- DTreceive & breaker trip

The report & relay indications provided by CE(T&C) is enclosed as Annexure - IRemedial Measures

400 KV Pithampur – SSTPS Ckt – I was charged from 400 KV S/s Pithampur end at 11:50 Hrs. andsynchronized at 12:02 Hrs. at SSTPS end.

400 KV Pithampur – SSTPS Ckt – II was charged and synchronized at 13:20 Hrs. on 02.01.2015 afterreplacement of Flashover Disc Insulator at location no-6.

Conclusion

The tripping occurred due to failure of ‘C’-Phase Disk Insulators at location No – 6 of 400 KVPithampur – SSTPS Ckt – II.

It is informed by CE(T&C), MPPTCL that auto reclosing of both (i.e., 400 KV Pithampur – SSTPS Ckt– I & II) 400 KV Ckt is kept blocked at SSTPS end. However it is proposed to keep the auto reclosure inservice for both 400 KV feeders at SSTPS end and Pithampur end to ensure reclose of feeders for phase toearth faults.

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Following information can be gathered from DR Files:- Fault current in 400 KV Pithampur – SSTPS Ckt – II was about 3.91KAmp. Circuit Breaker of 400 KV Pithampur – SSTPS Ckt – II at Pithampur end cleared the fault in 47.5msec

(Zone –I) which is found to be in order as fault was located near to 400 KV S/s Pithampur, at locationno-6. Carrier signal was generated & sent by protection relay at pithampur end but could not betransferred & received at other end through carrier channel. Hence ‘end to end testing’ of carrierprotection trip signal is being arranged.

Circuit Breaker of 400 KV Pithampur – SSTPS Ckt – II at SSTPS end, cleared the fault in 781.4msec(in Zone-III). The fault should have been cleared in 300-400msec in Zone-II hence relay setting of400 KV Pithampur – SSTPS Ckt – II shall be reviewed and tested at SSTPS end.

Due to delayed fault clearance of 400 KV Pithampur – SSTPS Ckt – II at SSTPS end or non-clearing ofZone-2 fault in time from SSTPS end, the fault persisted and was fed through 400 KV Pithampur –SSTPS Ckt – I (fault current in 400 KV Pithampur – SSTPS Ckt – I was about 1.39KAmp).Consequently 400 KV Pithampur – SSTPS Ckt – I tripped from Pithampur end and cleared the fault in829.4msec.(in Zone-III) which is found to be in order and Carrier signal was received at SSTPS end.

Generation Loss:- NIL

Load Loss:- NIL

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P a g e 1 | 6

Report on Oscillation at Sipat Power Plant on 1st January 2015

Event Summary: On 1st January 2015, Severe oscillations were observed in voltages of all most all

PMUs from 9:13 to 9:16 Hrs. The Oscillation severity was more observable in Western Grid. The 765

kV Solapur-Raichur D/C Power was oscillating with higher magnitude. Operators at NLDC were in

coordination with all RLDCs were analyzing the event in real time. It was reported by WRLDC that

during the period Sipat Unit 4 has tripped while desynchronizing. In the MVAR and MW plot of Sipat

Unit 4 the wide fluctuation was observed. NTPC also informed that Unit 4 active and reactive power

was fluctuating. After this a detailed analysis of the event was carried out which is presented here.

Event Description and Analysis: NTPC Sipat is a 765/400 kV generating station with one and half

breaking scheme with 5 generating units ( 2 X500 + 3 X 660 MW ) connected on 765 kV Bus. Its

evacuation is through 765 kV Sipat-Bilaspur-Seoni D/C and 765/400 kV 1000 MVA ICT 1 & 2.

Connectivity of Sipat sub-station is shown in figure 1.

Figure 1: WR Power Map showing 765 and 400 Kv lines along with major 220 kV lines.

On 1st January 205 Sipat Unit 4 was synchronized with the grid at 08:49 Hrs. The unit was generating

98 MW and was on speed control mode. At the time 09:13:58.993 Hrs as per WRLDC SOE, 7-8 kV as

shown in the voltage plot took out 765 kV Sipat-Bilaspur 1 circuit with its line reactor, which has

reduced the Sipat and Bilaspur Bus voltage by 7-8 kV as shown in figure 2 . During the period, Unit 4

at Sipat was being change over from speed control mode to load control mode of the turbine (Refer

Annexure). Due to the voltage dip during the line outage, there was a change in load feedback. This

has resulted in toggling of turbine control between speed control to load control, which resulted in

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Annexure - 2.10

P a g e 2 | 6

hunting from 15 MW to 270 MW in Unit 4. The hunting in Unit 4 can be observed in Active & Reactive

power as shown in figure 3. The other Units at Sipat have also observed active power fluctuation in

range of 10-20 MW as shown in appendix.

Figure 2: 765 kV Sipat and Bilaspur Bus voltage from WRLDC SCADA indicating voltage dip during opening of 765 kV Bilaspur-Seoni 1

Figure 3: MW and MVAR of Sipat Unit 4 from generator SCADA.

Apart from this, the oscillation was also observed in entire grid in frequency, voltages, active and

reactive power as measured from PMU located across the grid. The low frequency oscillation was

having frequency 0.2 Hz and was negatively damped. The same can be observed in the growing nature

of oscillation as shown in frequency, Voltage, and Power flow in figure 4, 5 and 6.

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P a g e 3 | 6

Figure 4: Frequency of various nodes in Western region from PMUs

Figure 5 : Positive Sequence Voltage of various nodes in Western region from PMUs

Figure 6 : Active Power flow of various feeders from PMUs

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P a g e 4 | 6

As it can be observed from the figure 5 that oscillation has triggered after the voltage dip due to

opening of 765 kV Bilaspur-Seoni 1 circuit. The hunting in the Sipat unit 4 was growing in nature.

Aattempt was made by Generating control room operator to take the turbine on hydraulic control but

unit tripped in the meantime on low forward power protection. After Unit tripping, the oscillation has

subsided in the grid.

Remedial Actions and Lessons learnt:

Whether the turbine controls system, malfunctioning was desired with change in system/bus

voltage? NTPC is requested to kindly look into the matter and discuss with the Generator

Manufacture.

Every time while a large Unit is just synchronised with the grid, such switching activities causing

change in voltage near to generating station has to be avoided in future. This will be ensured at

WRLDC and SLDC level.

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P a g e 5 | 6

Annexure

Figure 7: Sipat Unit 1 Generation from Generator SCADA



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P a g e 6 | 6


The turbine prime mover control system usually has three modes of operation:

1. Speed Control Mode

2. Load Control Mode

3. Pressure Control Mode

In the start-up phase, when generator circuit breaker is open, prime mover is controlled in speed

control mode. Adjusting the control valves, changes the total amount of steam flow entering steam

turbine, which is directly proportional to speed of rotation. Once generator is synchronized to the grid,

control system is in either load or pressure mode. In the load control mode, control error that

represents input to the controller is formed as a difference between set point and actual load.

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Annexure - 2.11

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Annexure - 2.12

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132kV Gotri Sub Station Campus, Opp. Kalpvrux Building,Near T.B. Hospital, Gotri Road, Vadodara – 390 021.

No. SLDC/MIS/GD/WTPS/160215 Date: 16/02/15

Sub: Report on grid disturbance occurred in Gujarat system on 21.01.15 at 12:54 Hrs.On 21.01.15 at 12:54 Hrs, grid disturbance occurred in Gujarat Power System. It led togeneration loss of around 570 MW at Wanakbori Thermal Power Station (WTPS).1. Date and Time of event : 21.01.15 at 12:54 Hrs.2. Location : Wanakbori TPS.3. Plant / Equipment directly

involved: 220 KV Bus - 1 tripping.

4. Description and cause of event :On date 21.01.2015, the position at 220 KV and 400 KV Switchyard was as under:

Unit – 1 – Under COH 220 KV Godhra – Under Outage

Unit – 2 – On bar 220 KV Asoj – 1 – On load

Unit – 3 – On bar 220 KV Asoj – 2 – On load

Unit – 4 – On bar 220 KV Kapadvanj – 1 – On load

Unit – 5 – Under RSD 220 KV Kapadvanj – 2 – On load

Unit – 6 – Under RSD 220 KV Dhansura – 1 – On load

Unit – 7 – On bar 220 KV Dhansura – 2 – On load

ST-1 – On load 220 KV Bus coupler - OFF

ST-2 – On load 400 KV Asoj - On load

ST-3 – On load 400 KV Dehgam – On load

ST-4 – On load 400 KV Soja – On load

220 KV side of ICT – On load 400 KV side of ICT – On load

On 400 KV side:1. 400 KV WTPS – Asoj line2. 400 KV S/C WTPS – Soja line3. 400 KV S/C WTPS – Dehgam (PG) line4. 400/220 KV, 500 MVA ICT5. Generator Transformer 250 MVA (15.75 KV / 400 KV) for Unit No. 4, 5, 6 and 7.

On 220 KV side:1. 220 KV D/C WTPS – Dhansura line.2. 220 KV D/C WTPS – Kapadvanj line3. 220 KV D/C WTPS – Asoj line4. 220 KV S/C WTPS – Godhra line5. Generator Transformer 250 MVA (15.75 KV / 220 KV) for Unit No. 1, 2 and 3.6. Station Transformer – 4 Nos. (220 / 7 KV)

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Annexure - 2.13

132kV Gotri Sub Station Campus, Opp. Kalpvrux Building,Near T.B. Hospital, Gotri Road, Vadodara – 390 021.

Prior to disturbance, WTPS Unit No. 2 & 3 (on 220 KV Bus) and 4 & 7 (on 400 KV Bus) were on bar.The unit auxiliary transformer ‘B’ of Unit No. 7 was under forced outage. Hence, the auxiliaries of UnitNo. 7 were on 6.6 KV station bus through 220 / 6.6 KV Station transformers. The outage of 220 KVS/C WTPS – Godhra line along with 220 KV Bus - 2 was availed from 10:06 Hrs for attending hotpoint of bus isolator clamp. All remaining 220 KV feeders were on 220 KV Bus - 1. So, one part of Bus- 2 isolators of all feeder bays (except 220 KV WTPS – Godhra line) were in live condition.Also, there was a planned work of attending hot point on 89 B isolator (Bus - 2) towards bus side of

220 KV WTPS – Dhansura line No. 1. The line outage of Dhansura-1 was asked by switchyard

maintenance engineer but was in process with SLDC for issuance.

Meanwhile lineman, who came from the switchyard electrical maintenance store after some work, has

clamped the free end of earth wire with structure earthing strip and moved up the earthing rod for

providing the earthing towards the R– phase of Bus–2 side isolator-89B of Dhansura-1 Line but has

moved towards live part of isolator and as soon it came in induction zone, a heavy spark and big sphere

of arc was occurred which has resulted in incident at 12.54 Hrs. All auxiliaries connected to Bus-1 i. e.

Unit no. 2, 3 and 7, all 220 KV Lines, ST-1, 2, 3, 4 and ICT tripped. There was a generation loss of 567

MW. The 400/220 KV, 500 MVA ICT at WTPS tripped on OLTC buchholz relay. Hence, after oil

filtration and testing, the ICT was taken into service on 23.01.15 at 17:19 Hrs.

As Busbar Protection Scheme was made OFF during the transfer of auxiliaries from Bus-2 to Bus-1,

Busbar protection did not operated and the 220 KV Lines tripped from opposite end. All Power

Stations are instructed to keep Busbar Protection Scheme in service during transfer of auxiliaries.

Unit no. 7, which was connected with 400 KV Bus, tripped on Reverse Power Protection as turbinetripped due to tripping of ST-4. UAT-7B was out also.

5. Remedial measures to be taken to avoid recurrence:Whenever there is a bus outage at any substation, adequate care is required to be taken for transportation oftools and tackles. A meeting may be conducted prior to carrying out any job so that all the precautionarymeasures to be adopted are to be clearly explained to all the persons involved in the work and the scope ofwork for each person is to be well defined.Thanking you,

Annexure: 1Sr.No.

Elements Duration Reason

1 WTPS Unit No. 2 21-Jan-15 12:54 22-Jan-15 00:59 12:05:00 Class "A" protection (98G-Pole slip relay)2 WTPS Unit No. 3 21-Jan-15 12:54 22-Jan-15 20:56 32:02:00 Class "A" protection (51 NGT, Genrator Impedance backup)3 WTPS Unit No. 7 21-Jan-15 12:54 21-Jan-15 17:36 4:42:00 Class "B" protection - Aixillary supply failed4 400/220 KV 500 MVA ICT at WTPS 21-Jan-15 12:54 23-Jan-15 17:19 52:25:00 LV side: 50 RYB,67 RYB, HV side: 50 RYB5 220 KV WTPS – Dhansura line No. 1 21-Jan-15 12:54 22-Jan-15 01:02 12:08:00 WTPS end: No relay, Dhansura end: Z 2 R-ph to E & Y-ph to E6 220 KV WTPS – Dhansura line No. 2 21-Jan-15 12:54 22-Jan-15 1:05 12:11:00 WTPS end: No relay, Dhansura end: Z 2 R-ph to E & Y-ph to E7 220 KV WTPS – Asoj line No. 1 21-Jan-15 12:54 21-Jan-15 13:22 0:28:00 WTPS end: Bkr tripped No relay, Asoj end: Z 2 R-ph to E & Y-ph to E8

220 KV WTPS – Asoj line No. 221-Jan-15 12:54 22-Jan-15 18:21 29:27:00 WTPS end: General trip, Z1 R-ph, carrier sent

Asoj end: Z 2 R-ph to E & Y-ph to E9 220 KV WTPS – Kapadvanj line No. 1 21-Jan-15 12:54 21-Jan-15 13:41 0:47:00 WTPS end: No relay, Kapadvanj end: Z 2 R-ph to E & Y-ph to E10 220 KV WTPS – Kapadvanj line No. 2 21-Jan-15 12:54 21-Jan-15 14:09 1:15:00 WTPS end: No relay, Kapadvanj end: Z 2 R-ph to E & Y-ph to E11 220 KV WTPS – Godhra line 21-Jan-15 12:54 21-Jan-15 22:57 10:03:00 Under shut down12 220 KV Bus - 1 21-Jan-15 12:54 21-Jan-15 13:22 0:28:00 LBB operated13 220 KV Bus - 2 21-Jan-15 12:54 21-Jan-15 22:57 10:03:00 Under shut down

Out Date In Date

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WANAKBORI TPS OCCURRENCE: 21-01-2015 AT 12:54 HRS.

220 KV Lines 400 KV Lines

GODHRA ASOJ KAPADVANJ DHANSURAZ2,R,Y

Z2, R,Y ASOJ DEHGAM SOJA

400/220 kV ICT 400 kV Bus - I1 2 1 2 1 2 315 MVA

LA

220KV BUS-I

F220KV BUS-II

B/C 400 kV Bus - II

ST-1 ST-2 ST-4 ST-3

----------------------------------------------------------------------------

Breaker Tripped Isolator Closed

Breaker Not Tripped Isolator Open

Breaker OFF (Under Outage/RSD)

G6 G7G5G4

G3G2G1

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WRLDC, Mumbai Page | 1

Detailed report on the Grid Incidence at 220/132 kV Damoh (MP) S/s on 23rd January 20151. Event Category : GI-12. Event Date and Time : 23rd January 2015, 11:28 hrs3. Event Summary : At 11:28 Hrs, R Phase CT of 220 kV Damoh-Katni 1 burst at Damoh (MP) Sub- stationwhich resulted in bus fault at 220 kV Damoh (MP). With this bus bar protection operated causing trippingof all 220 kV lines and 220/132 kV ICTs. With this, there was a load loss of around 14 MW of traction.5. Event Overview:Prior to incident all 220 kV lines and ICTs were either in service or ideal charge from 220/132 kV DamohSub-station. At 11:27 Hrs, R Phase CT failed for 220 kV Damoh-Katni feeder at Damoh end (SCT,Manufacture: 1995, Installation: 2000) resulting in R phase Bust fault on 220 kV bus of220/132 kV Damoh Sub-station. This led to Bus bar operation at 220 kV Damoh resulting intripping of all ICTs and lines. 132 kV System at Damoh S/s remain intact with the system.

Table 1 : The sequence of tripping and restorationSl

No.Name of the transmission

element/ UnitTime ofTripping

Relayindication End 1

RelayIndication End 2

Time ofrestoration

1 220 kV Damoh-Katni ( 400 kVfeeder charged at 220 kV)

11:28

R Phase toearth fault,

Zone 1, 0.02km. A/R

attempt butfault persist

- 15:3025-01-15

2 220 kV Damoh-Damoh(PG) 1 11:28Bus bar

protection - 12:15

3 220 kV Damoh-Damoh(PG) 2 11:28Bus bar

protection -

4 220 kV Damoh-Sagar 11:28Bus bar

protection - 11:55

5 220 kV Damoh-Traction 1 11:28Bua bar

protection - 11:56

6 220 kV Damoh-Traction 2 11:28Bua bar

protection - 12:05

7220/132 kV 160 MVA ICT(BHEL) 11:28

Bua barprotection - 12:15

8220/132 kV 160 MVA ICT(AREVA) 11:28

Bua barprotection - 12:15

9 220/132 kV 120 MVA ICT (TELK) 11:28Bua bar

protection - 12:15Load / Generation affected: Traction load of 14 MW got affected for 21 minutes during the tripping. Theenergy not served was 4.9 MWHr.Frequency Change : Frequency did not change during the event as load loss was insgnificant in quantum.Restoration: 220 kV Supply at 220/132 kV Damoh S/s was resumed by charging 220 kV Damoh

– Sagar line at 11:55 Hrs. Subsequently rest of the feeders were taken back in service one by one as perthe above table.

7. Analysis: So the fault was a result of bursting of R phase CT of 220 kV Damoh-Katni at Damoh end.From the event log of Damoh sub-station it was observed that initially the R phase fault hasoccurred on the 220 kV Damoh-Katni line at 0.02 km and during the auto reclosure after 879 ms , the Rphase CT of the circuit at Damoh end has burst resulting in the Bus fault at 220 kV Damoh S/s. This is thereason in figure 2 Itarsi voltage is having double dip at an interval of 840 ms. The net fault current wasaround 11.3 kA, which was being fed from the Damoh end as circuit was in open condition from Katni end.

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WRLDC, Mumbai Page | 2

-1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.7t/s

5

-1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.7t/s

5

-1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.7t/s

5

CARRIER RX On86 RELAY On

TRIP 3 POLE OnA R INIT On

AR FORCE 3P TRIPAR LO

6. Graphical plot:

Figure 2 : Itarsi PMU voltage indicating two faults in the system.Trigger

23-01-201511:28:56.731

F1-IA A/kA

7.5

5.0

2.5

0.0

F2-IB B/A

403020

10 -1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75t/s

F3-IC C/A

40302010 -1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

0

t/s

F4-IG G/A

2.0

1.5

1.0

0.5

-1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75t/s

F5-VA A/kV

100

7550

25

0

F6-VB B/kV

100

7550

25

0

F7-VC C/kV

100

75

50

25-1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

t/s

F8-VN N/V

75

50

25 -1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75t/s

OSC TRG OnCB-A PH OnCB-B PH OnCB-C PH On

-1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.7

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Ref. No.: - MSETCL/SE/T&C/Circle/AKL/Tech/I-2/ 0040 Date: 02.02.2015

Sub: - Occurrence dated 27.01.2015 at 220 KV Ghatodi substation – Analysis thereof.

A) Occurrence details:On Dt. 27.01.2015 at 9.16 Hrs, 220 KV Ghatodi - Pusad Line tripped at 220 KV Pusad S/stn. due to

the wrong operation carried out at 220 KV Ghatodi end. Simultaneously tripping occurred on 220 KVPusad-Yavatmal line at 220 KV Yavatmal S/stn., 220 KV Pusad-Bhugaon line at 220 KV BhugaonS/stn., 132 KV Mehkar line at 220 KV Chikhali S/stn and 132 KV Malegaon line at 132 KV PaturS/stn. The details of the trippings are as given below:

Slno.

Name ofthe

substation

Name of theline/ bay.

Date andtime of thetripping &restoration.

Relay indications Remark

1.220 KVGhatodi

S/stn

220 KVPusad Line

27.01.20159.16 Hrs to12.47 Hrs

Dur. 3.31Hrs.

Dist: R Y B pick up.

No tripping, asPusad line CB wasalready hand trippedand Bus & lineisolator were open.

2.220 KVPusadS/stn

220 KVGhatodi Line

27.01.20159.16 Hrs to12.47 Hrs

Dur. 3.31Hrs.

W.I :- (i) Distance prot. Opt.(ii) Back up Prot. Optd.(iii) A/R LockoutR.I.:-i)Distance Prot. Opt. R-ph, Y-ph,B-ph trip, earth, Zone-2 , Distance 19.4 KM,(ii)3 ph trip relay(iii) Back up Relay:trip,AF,BF,CFCB Tripped on fault inZone-II at Pusad end.

3.220 KV

YavatmalS/stn

220 KVPusad Line

27.01.20159.16 Hrs to

9.54 Hrs Dur.38Min.

W.I. : Distance Protectionoperated, Auto Reclose Lockout operated, Carrier FailR.I. : 3 phase tripping Relay,Distance Protection relay:Rph trip, Yph Trip, Bph trip,Earth trip, Zone 2, Distance =128.8 kMCB tripped at

Yavatmal end inZone-II.

No tripping at Pusadend.

4.220 KVBhugaon

S/stn

220 KVPusad Line

27.01.20159.16 Hrs to

9.5 Hrs Dur.34Min.

W.I. : Distance Protectionoperated, Auto Reclose Lockout operated, Carrier failR. I. : Distance Protectionrelay : Rph Pick up, Yph Pickup, Bph Pick up, Earth, Zone2,Distance = 206 KmCB tripped at

Bhugaon end inZone-II

. No tripping atPusad end.


[email protected]


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Annexure - 2.15

5.220 KVChikhali

S/stn

132 KVMehkar Line

27.01.20159.16 Hrs to

9.43 Hrs Dur.27min.

At Chikhali endW/I- Back up ProtectionOperatedR/I -Master trip86, B/U O/Crelay132 KV Mehkar Linetripped on overload at

Chikhali end.Tripping is in order

6.132 KV

PaturS/stn

132 KVMalegaon

Line

27.01.20159.16 Hrs to

9.23 Hrs Dur.7Min.

At Patur endW/I- OC Operated , Trip R-Y-BPhR/I -Master trip86132 KV Malegaon

Line tripped onoverload at Patur end.Tripping is in order

B) Investigation/Analysis:

At 220 KV Pusad S/stn. 132 KV Pusad – Ghatodi line and 220 KV Pusad- Hingoli line were

already hand-tripped at Pusad end only as per LDs instruction due to System Constraint. The outage

was proposed by Pusad for 132 KV Pusad-Ghatodi line for measurement of C & Tan-Delta of CT,

CRM & Timing of CB. As this ckt was already out, the outage was approved by LD. The staff at

Pusad S/Stn. has carried out the operation of 132KV Pusad – Ghatodi line and informed accordingly

to Ghatodi S/Stn to carry out operation at their end. However the staff at Ghatodi S/Stn carried out the

operation of 220 KV Ghatodi- Pusad line instead of 132 KV Ghatodi- Pusad line. Finally they closed

the earth isolator of 220 KV Ghatodi- Pusad line at Ghatodi S/stn. and tripping as stated above took

place.

The analysis of these trippings is as follows,

At 220 KV Ghatodi S/Stn, breaker of 220 KV Ghatodi – Pusad line was Hand tripped, Bus &

line isolator were opened. As soon as the E/S was closed at Ghatodi end for 220 KV Pusad – Ghatodi

line, 3Ph. to E/F occurred and the 220 KV Ghatodi – Pusad line tripped at Pusad end in Zone II. The

tripping of this line is in order.

Simultaneously, the 220 KV Pusad – Yavatmal Ckt tripped at Yavatmal end and 220 KV

Pusad – Bhugaon Ckt tripped at Bhugaon end on Distance protection in Zone II. As the fault was of

arching type the Distance Protection scheme sensed the fault in Zone II at both Bhugaon & Yavatmal

end. Both these lines are of long distance followed by short distance and due to the arching type of

fault, have over reached and tripped in zone-II. The time setting adopted for Zone-II is 350 ms.

Simultaneously, at the same instance the 132 KV Mehkar line at Chikhali and 132 KV

Malegaon line at 132 KV Patur S/stn got overloaded and tripped on over current. Due to tripping of

both source lines i. e. 220 KV Yavatmal – Pusad & 220 KV Bhugaon – Pusad at Pusad, the total load

of 132 KV Bus at Pusad shifted on 132 KV Pusad – Jambazar line. The Jambazar is fed through 132

KV Jambazar –Washim – Malegaon – Mehkar – Chikhali and 132 KV Jambazar –Washim –

Malegaon – Patur – Paras. The over current setting of 132 KV Mehkar line at Chikhali is 70% with

the connected CT ratio of 800/1 i.e. 560 Amp. and 132 KV Malegaon line at Patur is kept 120 % with

the connected CT ratio of 400/1 i.e. for 480 Amp, as the conductor is of 0.15. The current recorded at

Chikhali & Patur were 599 Amp & 536 Amp respectively. Hence the tripping of 132 KV Mehkar at

Chikhali and 132 KV Malegaon at Patur on over load is in order.

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As such, the total area of Pusad, Jambazar, Umarkhed, Gunj, Washim, Mangrulpir, Karanja,Malegaon & Mehkar S/Stns. were affected.

C) Area affected: -

Total load affected was around 225 MW at following S/Stns.

220 KV Pusad S/Stn. – 34 MW for 12 Min.

132 KV Gunj S/Stn. – 25 MW for 23 Min.

132 KV Umarkhed S/Stn. – 25.2 MW for 23 Min.

132 KV Jambazar S/Stn. – 8.7 MW for 07 Min.

66 KV Digras S/Stn. – 5.5 MW for 12 Min.

132 KV Karanja S/Stn. – 20 MW for 07 Min.

132 KV Mangrulpir S/Stn. – 14.6 MW for 07 Min.

132 KV Malegaon S/Stn. – 33 MW for 07 Min.

132132 KV Washim S/Stn. – 21.8 MW for 07 Min.

132 KV Mehkar S/Stn. – 40 MW for 07 Min.

D) Remedial Measures: -

1. The operating staff on duty/ shift incharge should be cautious and vigil while carrying out –operation during outages and trippings at S/Stn. so that such type of manual error should

not take place and cascade tripping / supply failure in the EHV Network will be avoided.

2. Delay in charging of ckt should be avoided.

3. WRPC in their MOM Dt. 08.01.2015 of the special meeting held on 18.12.2014, on page

no. 8 stated that the time setting recommended & adopted for Zone-II at present is 350

msec. However for long line followed by short line the Zone-II time setting of 500 msec. is

recommended to be adopted. The copy of the page no. 8 of the above MOM is enclosed

h/w for your ready reference

Submitted please.

Encl: Single line diagram & MOM.Sd-

SUPERINTENDING ENGINEERTESTING & COMMUNICATION CIRCLE

MSETCL, AKOLACopy s.w.r.to:

1) The Chief Engineer, Trans (O&M), C.O., MSETCL, Mumbai.-------It is requested to issue necessary guidelines for zone-II time setting when long line is

followed with the short line as suggested by WRPC mentioned under remedial action 3.2) The Chief Engineer, SLDC, Kalwa.

Copy f.w.c.to:1) The Superintending Engineer, Trans O&M Circle, Amravati.2) The Superintending Engineer, LD Centre, Ambazari.

Copy to:1) The Executive Engineer, Testing Division, MSETCL, Yavatmal.

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Single Line Diagram of Occurrence at 220 KV Ghatodi S/Stn. on Dt. 27.01.2015.

: - CB Tripped

: - Already H/T as per LD

: - CB Not Tripped (In ONCondition as per Normal)

: - CB H/T- wrong operation

132 KV Mangrulpir

132 KVKaranja

132 KVParas

132 KV Malkapur132 KV W. Bakal132 KV Akot

132 KVPatur

132 KV

132 KVMalegaon

220 KVChikhali

132 KV

132 KV J.Bazar

132 KV Gunj

132 KV Umarkhed

Hingoli

220 Bhugaon

Yavatmal

220 KVGhatodi

220 KVNanded

E/S Closed

132 KV

220 KV Pusad S/Stn.

220 KV 132 KV

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Ref. No.: - MSETCL/SE/T&C/Circle/AKL/Tech/ I-2/ 0041 Date: 02.02.2015

Sub: - Occurrence dated 31.01.2015 at 220 KV Ghatodi substation – Analysis thereof.

A) Occurrence details:On Dt. 31.01.2015 at 11.31 Hrs, 220 KV Ghatodi - Pusad Line tripped on transient fault. The line

Auto-reclosed at 220 KV Pusad end but tripped at 220 KV Ghatodi end. Simultaneously 220 KVGhatodi- Nanded line tripped at Nanded end. The details of the trippings are as given below:

Slno.

Name ofthe

substation

Name of theline/ bay.

Date andtime of thetripping &restoration.

Relay indications Remark

1.220 KVGhatodi

S/stn

220 KV PusadLine

31.01.201511.31 Hrs to

12.10 HrsDur. 39 Min

SCADA Indications. : Zone2, R Ph Pick up,86 A relay OperatedR.I. :1) 86 A Trip2) Distance relay: I Rph=1.392 KA, Dist. = 18.16 kM

Pusad line CBTripped.

2.220 KVPusadS/stn

220 KVGhatodi Line

31.01.201511.31 Hrs to

11.31 HrsDur.

0.00Hrs.

W/I:-1. Distance protectionoperated2. Autoreclose operatedR/I:-1) Tripping relay VAJ2 ) R phase trip, Earth, Zone-I, General Trip, I Rph = 3.80KA.

Line Auto-reclosed atPusad end.

3.220 KVNanded

S/stn

220 KVGhatodi Line

31.01.201511.31 Hrs to

12.08 HrsDur. 37Min.

W/I: 1)Distance protectionoperatedR/I: 1)Distance relay R-Y,earth, Zone-2 ,Distance 149.26 KMfault current I Rph-1078.62amp

CB tripped atNanded end

only.


[email protected]


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Annexure - 2.16

Investigation / Analysis: -

1. The 220 KV Pusad – Ghatodi line tripped on Rph Transient fault. The line was auto-reclosed successfully

at Pusad end in Zone I. The operation of protection at Pusad end is in order.

2. However the line tripped at 220 KV Ghatodi end in Zone-II. As the fault was in Zone II for Ghatodi, it

should have auto-reclosed in Zone I extension through carrier (PLCC). But the line was not auto-reclosed

and tripped in Zone II. Immediately testing and telecom staff rushed to Ghatodi & Pusad S/Stn to identify

the cause of non auto-reclosing. It was observed that carrier command is sent from Pusad end, send

counters advanced i. e. from 27 to 28, but the command was not received at 220KV Ghatodi end, counter

not advanced at Ghatodi end. After detail testing of PLCC and protection coupler it is observed that DC-

CPU has gone faulty. The same was replaced. The carrier inter-trip trails taken and found normal.

3. The tripping of 220 KV Ghatodi – Nanded at Nanded end is in Zone II. Line is of long distance followed

by short distance and has over reached and tripped in zone-II. The time setting adopted for Zone-II is 350

ms.

Area Affected: -

132 KV Darwha & Digras affected total – 44 MW for 39 min.

Remedial Measure: -1. This office has already instructed Testing &Telecom staff to carry out cold trials on monthly basis for

ensuring the healthiness of PLCC, protection coupler & to submit report on monthly basis.

2. The duration of restoration of line could have been curtailed hence operation staff should have instructed

for early restoration.

3. WRPC in their MOM Dt. 08.01.2015 of the special meeting held on 18.12.2014, on page no. 8 stated that

the time setting recommended & adopted for Zone-II at present is 350 msec. However for long line

followed by short line the Zone-II time setting of 500 msec. is recommended to be adopted. The copy of

the page no. 8 of the above MOM is enclosed h/w for your ready reference.

Submitted please.Encl: Single line diagram & MOM.



Copy s.w.r.to:1) The Chief Engineer, Trans (O&M), C.O., MSETCL, Mumbai.

------It is requested to issue necessary guidelines for zone-II time setting when long line isfollowed with the short line as suggested by WRPC mentioned under remedial action 3.

2) The Chief Engineer, SLDC, Kalwa.Copy f.w.c.to:

1) The Superintending Engineer, Trans O&M Circle, Amravati.2) The Superintending Engineer, LD Centre, Ambazari.

Copy to:1) The Executive Engineer, Testing Division, MSETCL, Yavatmal.2) The Executive Engineer, Telecom Division, MSETCL, Amravati.

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Sinle Line Diagram of Occurance at 220 KV Ghatodi S/Stn. on Dt. 31.01.2015.

: - CB Tripped

: - CB A/R

: - CB Not Tripped (In ONCondition as per Normal)

: - H/T already as per LD

132 KVBus

220 KVBus

132 KV Ghatodi - Pusad

220 KVNanded

220 KV Ghatodi S/Stn.

220 KV Bus Ghatodi

132 KV Bus

132 KVDigras

132 KVDarwha

TransientFault

220 KV Pusad S/Stn.

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Annexure - 2.17

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REPORTING OF OPERATION EVENT / ACCIDENT 11th-FEB-2015

AS PER IEGC 2010i Time & Date of event AT 00:20 Hrs & DT. 11/02/2015ii Location 400KV SATPURA SUB STATION,PH-III: SARNIiii Plant and/or equpment directly involved Generator No. 8

iv Description and cause of event

AT around 00:20 Hrs, Gen #8 of PH-III tripped on class -Aprotection. The relays HV Earth fault, O/A Diff. Prot. , REF Prot.appeared.During this it was raining and lightining. After checkingin 400KV SWYD, B-phase CT found damaged & CT oil drained out.

v Antecedent conditions of load and MW : 173 MWGeneratiopn,including frequency,Voltage Voltage: 16.30 KVand flow in the affected area at the time Frequency : 50.12 Hz.of tripping including Weather condition Weather : Heavy Rainprior to the event

vi Damage to equipment, if any The 400KV B-phase CT failed.vii Supply interrupted (MW & MWH) and

duration, if applicable …………………..viii Amount of Generation lost (MW & MWH) MW MWH Duration

if applicable 173MW 5665.75 MWH 32 Hrs.& 45 minutesix Possibility of alternate supply arrangment …………………..x Estimate of time to return service

…………………..xi All relevant system data including copies DR Enclosed

of record of all recording instrumentsincluding DR,ER,DAS etc.

xii Sequence of tripping with time Yesxiii Details of relay flags 86G1 Trip, O/A Diff. Trip, HV REF Trip, 86T Trip, HV E/F Tripivx Remedial measure

xv Recommendations for future NILimprovement/repeat incident

xvi Any other information After clearance unit light up and synchronised at 09:05 HRS on12/02/2015.

SUPERINTENDING ENGINEER. STPS : M.P.P.G.C.L.: SARNI

The 400KV damaged CT replaced by spare CT. Testing of GT#8, R-ph & Y-ph CTs carried out. The replaced CTs of B-ph was also testedand found ok.

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Annexure - 2.18

Flash Report : SLDC/STU/Users/Transmission agency/Generators

Agency GMR EMCO ENERGY LTD/Month-Year/GD or GI- NumberName of Incident: GMR EMCO Energy Line -2 tripped on B phase E/F on 13 feb at 16:32 Hrs.1. Date and Time: 13/02/2015 and 16.32 Hrs2. Antecedent Conditions

I. Frequency of NEW Grid/SR Grid

Event Frequency Time(hh:mm)Pre incident 50.00 16.31Post Incident 50.18 16.32

II. Demand Met State Generation State Load

3. Event Description: Event and Likely cause as reported by SLDC and as observed.The Event recorded in relay is as per the following:System Frequency – 50.18 HzFault Duration: - 74.73msFault location: - 25.05 KmIA- 758. 0AIB- 463.4 AIC- 4401 AVAN-240.6 kVVBN-233.1 kVVCN-95.51 kVFault Resistance – 16.05 OhmFault Zone- Z1

4. Lines/ICT/Units tripped and Restoration

Lines/ICT/Unit Tripped Restoration TimeLINE-2 Tripped on B Phase Earth Fault ( Z-1 ) 2 Hr.41 Mins

5. Areas Affected By Disturbance :1) Line-2 sensed B phase Earth fault and tripped on Zone-1 ( 52-410 Line &52-411 Tie)2) GMR EMCO unit-2 tripped due to turbine trip.

6. Load Loss /Generation LossGen Loss- 0.98 MU

7. Actions Taken: Restoration /Extension of supply power/self-starting of generating unitThe fault recorded at 25 km away from GMR EMCO station. Accordingly the line patrolling carried outacross the suspected towers i.e from 65 to 77 no tower which were at distance of 20 to 26 KM fromGMR EMCO station and no abnormality found. Subsequently the line was charged at 19.13 Hrs. fromGMR EMCO breakers and immediately after taken into load.(Shift Charge Manager)

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Annexure - 2.19

At 220KV Kanhan S/Stn on dtd. 16.02.2015 at 05:30Hrs, 220KV ‘B’ Ph CT of 220KV Suryalaxmi feeder failed, resulted in tripping of 220KV Bus (ABB make RADSS scheme) alongwith connectedfeeders . Cause of CT failure seems to be failure of insulation.

220 KV Kanhan Bus

132KV Kanhan Bus

220KV Suryalaxmi

220KV Khaperkheda220KV Umred



220KV Bhandara

SLD for Bus fault at 220KV Kanhan S/Stn on dtd. 16.02.2015

Fault

220 KV Kanhan Bus

132KV Kanhan Bus

Breaker ON

Breaker Trip

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Annexure - 2.20

Maharashtra State Electricity Transmission Co. Ltd.

MAHARASHTRA STATE ELECTRICITY TRANSMISSION CO.LTD.From:Name of Office: Superintending Engineer TCC

Office address: Block No.12 MSETCL AdminBldg. Racca Plot, Old SaykhedaRoad, Jail Road, Nashik (422101)

Contact No: 2403181Email Id: [email protected]

To,The Chief Engineer,Trans O&M, MSETCL, C.O.Mumbai.

Ref. No. SE/TCC/NSK/T/No. 087 Date: 16/03/15

Sub: Occurrence report of busbar operation at 220kV GCR Eklahare S/S due bursting of bus section-ICT on dt. 23.02.2015

Ref: No. EE/TD/NSK/TECH/T-4/52 Date: - 25.02.2015

On dated 23.02.2015 at 18.15 Hrs, 220 kV Bus section 1’s GCR Side ‘B’ Ph CT Burst, causingoperation of 220kV Zone-A Bus bar protection at 220 kV GCR Eklahare SS and resulted tripping of all220kV lines and ICT’s, station T/F & Gen. Unit connected to Zone-A,on following indications.

SN Name of Bay W.I R.I1 220 kV Bus Section 1 Nil Nil2 200 MVA ICT 6 Nil 86 (HV & LV)3 200 MVA ICT 1 Nil 86 (HV & LV)4 150 MVA ICT 2 Nil 86 (HV & LV)5 220 kV Kalwa line Nil 86 (TR221)6 220 kV BBLR 1 Line Nil 86 (TR221)7 Generation Unit 3 Nil Nil8 Station TF 3 Nil Nil9 220 kV Bus Section 2 Nil Nil10 220 kV TBC (220 KV

BBLR 2 Line was on TBC)Nil Nil

11 220 kV Bus Bar Panel Zone A Optd, Bus bar Tripping Relays (96)1) 220 kv Bus Section 12)200 MVA ICT-63)200 MVA ICT-14)150 MVA ICT-25)220 KV Kalwa line6)220 KV BBLR-1 Line7) GEN Unit-38) Station T/F-39) 220 kv Bus Section-210) 220 KV TBC

Analysis:

On date 23.02.15, the 220 kV B/S 1’s GCR side Bph CT burst due to thermal run away ofinsulation (even though tandelta results were in order) and caused a bus fault in 220kV Bus bar Zone-A.Hence operation of Zone-A Bus bar protection took place at 220 kV GCR Eklahare SS and resulted intripping of 220 kV lines, 220/132 kV ICTs, GEN T/F-3, Station T/F-3, 220 kV TBC, 220 KV BusSection 1&2 correctly. Bus bar protection operated correctly.

Details of Failed CT:

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Annexure - 2.21

1 Make Victrans2 Ratio 2400-1200/1-1-1-1-1.3 Sr. No. VE/C -187102174 Date of Comm. 22.02.2011.C & tan d results of failed CT

Date of Testing Capacitance 10 kV Tan d 10 kV1 12.01.2011 C= 389.7 PF Tan δ= 0.123%2 13.07.2013 C= 391.9 PF Tan δ= 0.364%3 18.09.2013 C= 390.57 PF Tan δ= 0.372%4 28.05.2014 C= 386.51 PF Tan δ= 0.26%

Details of New Installed CT:1 Make MEHRU2 Ratio 2400-1200/1-1-1-1-13 Sr. No. OC 5586/1/9/154 Date of Comm. 23.02.2015 .5 C & tan d results C= 520.67PF Tan δ= 0.27%

Damages: Support insulator of Bus section 1’s GCR side isolator broken and fallen on ground.Area affected: NilGenration Loss: Gen Unit 3 -145 MW & Gen Unit 5 – 145 MW Tripped later may be due to Auxilorysupply failure.

Restoration:

Sr. no Name of Bay Restoration Date/Time1 220 kV Bus Section 1 03.13 Hrs 24.02.20152 200 MVA ICT 6 19.21 Hrs 23.02.20153 200 MVA ICT 1 19.19 Hrs 23.02.20154 150 MVA ICT 2 19.20 Hrs 23.02.20155 220 kV Kalwa line 19.32 Hrs 23.02.20156 220 kV BBLR 1 Line 19.33 Hrs 23.02.20157 220 kV Bus Section 2 19.16 Hrs 23.02.20158 Generation Unit 3 21.54 Hrs 23.02.20159 Generation Unit 5 22.00 Hrs 23.02.201510 220 KV TBC ( BBLR-2 LINE) 19.34 Hrs 23.02.201511 Station TF 3 19.30 Hrs 23.02.2015

Remidial Measures:

1) The C.O. has procured 21 No new CTs (out of 09 No of ratio 2400-1200/1-1-1-1-1 and 12No1200-600/1-1-1-1-1 ) and received at ss for replacement of bus section CT at Eklahare ss.Thetotal 07No CT of ratio 2400-1200/1-1-1-1-1 were replaced i.e. for BS-2 06 Nos and 01 No forBS-1 and remaining CT will be replaced on priority.

Encls: SLDSuperintending Engineer (TCC),

MSETCL, Nashik

Copy s.w.rs.to :1) The Chief Engineer, EHV CC O&M Zone, MSETCL,Nashik.2) The Chief Engineer, SLDC, MSETCL,Kalwa.Copy f.w.cs.to :1) The S.E., EHV O &M, Circle, MSETCL, Nashik.2) The S.E., ALDC, MSETCL, Ambazari.Copy to:1) The E.E., Testing Dn., MSETCL, Nashik.2) The E.E., EHV O&M Dn., MSETCL, Nashik.

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schematic diagram showing Occurrence on dated 23.02.2015 at 18:15 hrs at220 kV GCR Eklahare S.S.

CB Tripped CB not Tripped CB already OFF

B/S -1 B/S -2 B/S -3

G-3 G-4

Station TF 3 Station TF 4

200 MVA,ICT 6

200 MVA,ICT 1

200 MVA,ICT 2

BBLR 1 Kalawa Ghatghar

BBLR 2

ZONE A

ZONE B

ZONE C

ToOCR

220 kV Bussection 1’sGCR Side ‘B’Ph CT burst

G-5

TBC

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Annexure - 3

Date Time Date Time

1 765 Sasan - Satna - II 12.02.2015 13:16 DT received at Sasan end

2 765 Sasan - Satna - II 14.02.2015 10:10 DT received at Sasan end

3 400 New Koyna-Stage 4-Ckt-2 3:22 7:30 DT carrier recieved,Definite trip A/R Lock out

4 400 New Koyna-Karad-Ckt-1 3:24 O/V trip ,Definite trip A/R Lock out

5 400 New Koyna-Stage 4-Ckt-1 3:24 9:18 DT carrier recieved,Definite trip A/R Lock out

6 400 New Koyna-Jaigad-Ckt-1 3:24 7:43 DT carrier recieved,A/R Lock out

7 400 New Koyna-Jaigad-Ckt-2 3:24 9:33 O/V trip ,Definite trip A/R Lock out

8 400 New Koyna-Karad-Ckt-2 3:33 8:22 O/V trip ,Definite trip A/R Lock out

9 400 New Koyna-Dabhol-Ckt-2 3:24 7:53Line trippped at Dabhol end but did not trip at NK hence handtripped at NK at03:54 hrs

10 400 125 MVAr bus reactor at Warora 17.12.2014 17:57 17.12.2014 18:18 While charging it tripped on differential protection

11 400 SSP - Rajgarh 14.01.2015 11:22 14.01.2015 18:22 Line tripped on distance protection

12 400 Khaparkheda - Chandrapur 25.01.2015 13:14 25.01.2015 13:14 Yes A/R operated successfully at both ends

13 400 BRS-KATNI-II 04.02.2015 13.36 04.02.2015 14:11 Yes Line tripped due to Earth fault,DT received from other end. 86 Relay operated

14 400 SSP - Dhule 08.02.2015 13:01 Yes Line tripped on distance protection

15 400 Sarni - Koradi 11.02.2015 01:53 11.02.2015 03:18 YesLine Tripped on R-Phase fault, main-1 and main-2 protection operated on R-phase to ground fault ,RN= 46.2 %

16 400 Koradi - Sarni 11.02.2015 01:54 11.02.2015 03:18 Yes A/R successfully operated at Koradi end & tripped at Sarni end.

17 400 Warora - Chandrapur 11.02.2015 06:06 11.02.2015 06:06 Yes A/R operated successfully at both ends

18 400 Koyna Stage IV - Lonikhand 21.02.2015 21:54 21.02.2015 22:36 Line tripped on Distance Protection (B Ph - N: B Ph string decapped)

19 400 125 MVAr bus reactor at Warora 28.02.2015 01:54 28.02.2015 21:13 Tripped on differentail protection

20 220 TAPS-Bhilad 22.12.2014 12:07 22.12.2014 15:40 Line tripped on transient fault. Ph R & Y trip.

21 220 TAPS-Vapi 26.12.2014 10:29 26.12.2014 10:57 Line tripped on transient fault. C Ph picked up.

22 220 Birsingpur - Satna 11.01.2015 01:40 11.01.2015 01:59 Yes Line tripped on R Ph E/F in Zone - I

23 220 Sarni - Itarsi - II 15.01.2015 11:11 15.01.2015 11:34 No Line tripped in Zone - I

24 220 Amarkantak - Annupur - II 31.01.2015 11:20 31.01.2015 11:31 Yes Line tripped on R Ph E/F in Zone - I

25 220 TAPS-Vapi 31.01.2015 11:58 31.01.2015 17:29 Line tripped on transient fault. C Ph picked up.

26 220 AMK-BRS -III Feeder 01.02.2015 6:37 01.02.2015 12.24 Yes Line trpped due to À` phase fault, Zone-1

27 220 BRS-SATNA 08.02.2015 17.39 08.02.2015 18.19 Yes Line trpped due to À` phase fault, Zone-1, Dist. 157 Km from Brs end

28 220 Amk-Panagar Feeder 09.02.2015 6:20 09.02.2015 6:45 Yes Line tripped due to `B` phase fault, Z-1

29 220 BRS-SHUKHA 09.02.2015 12.39 09.02.2015 13.25 Yes Line tripped due to `C` phase fault, Z-II

30 220 TAPS-Bhilad 13.02.2015 11:42 13.02.2015 12:39 Line tripped on transient fault Ph C to E/F

31 220 BRS SATNA 20.02.2015 21:30 20.02.2015 21.41 Yes Line tripped due to Phase À` fault, DPR optd., Dist. 154 Km. from BRS end.

32 220 TAPS-Bhilad 22.02.2015 12:29 22.02.2015 12:58 Line tripped on transient fault. Ph B DPS, DPT picked up.

33 220 AMK-Jabalpur - I 26.02.2015 3:30 26.02.2015 3:40 Yes Line tripped due to `B-N` phase fault, Z-1

Single line trippings from 01.12.2014 to 28.02.2015

kVS.

No.Reason

A/RStatus

Trip RestoredElement

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