no. nrpc/opr/107/1/2014/ dated: 03.02.2015 fax message

भारत सरकार उ र क्षतेर्ीय िव तु सिमित

18-ए, श.जीत िसह मागर्, कटवािरया सराय, नई िदल्ली- 110016

Government of India Northern Regional Power Committee

18-A, S. Jeet Singh Marg, Katwaria Sarai, New Delhi-110016

No. NRPC/OPR/107/1/2014/ Dated: 03.02.2015

FAX MESSAGE From : Superintending Engineer (O), NRPC. To : Members of Protection Sub-Committee (As per List) Sub : Sub:-Minutes of 28th Protection sub Committee Meeting. The 28th meeting of Protection Sub-Committee was held on 19.12.2014 at Ludhiana, Punjab. The minutes of the meeting are available on NRPC website at http://www.nrpc.gov.in Sd/-

(Ajay Talegaonkar) SE (Operations) & Member Convener PSC

फोन -26511211 , 26868681 फेक्स Fax : 26865206 ई मेल e- mail: [email protected] वेबसाईट Website : www.nrpc.gov.in

List of Members of Protection Sub-Committee

1. Director (P&C)/BBMB, Chandigarh, Fax-0172-2652054 2. General Manager (SLDC), Fax No 011-23236462 3. GM (O&M), Delhi Transco Limited, New Delhi, Fax-011-23236462 4. GM (T), Common Services IPGCL, New Delhi, Fax-23370247 5. Chief Engineer (TS), HVPNL, Panchkula, Fax-0172-2591244 6. SE (M&P), HVPNL, Dhulkote , Haryana, Fax-0172-2540014 7. SE (SO & SLDC), HVPNL: 0181-2664440 Fax-0172-2560622 8. SE (SLDC),PTCUL Fax- 0135-2451160, 0135-2763570 9. Chief Engineer (SLDC),UPPTCL, Fax- 0522-2287880, 2288736 10. SE (Tech).,HPGCL,Fax-0172-5022436,SE(O&M-VI),Panipat Fax:0180-2566768. 11. Chief Engineer (Transmission), HPSEB, Hamirpur, Fax-01972-223435 12. Chief Engineer (Comml. & Survey Wing) PDD, Jammu, Fax-0191-2474233 13. Chief Engineer (SLDC), Fax – 0175-2365340 14. Chief Engineer (P&M), PSTCL, Ludhiana, Fax-0161-2741280, 2451491 15. CE (M&P), RRVPNL, Jaipur, Fax-0141-2291891 16. SE (Electrical), RRVUNL, Suratgarh, (Rajasthan), Fax-01509-245299 17. Chief Engineer (LD); SE (SO&LD) – Fax- 0141-2740920 18. Superintending Engineer (T&C), UPPCL, Meerut (U.P.), Fax-0121-2666062 19. Chief Engineer, (L-2), UPRVUNL Lucknow, Fax-0522-2287822, 2287880 20. DGM (T&C), PTCUL, Dehradun, Fax-0135-2760331 21. Chief Engineer (O&M), NHPC, Faridabad, Fax-0129-2272413

22. NPCIL (i) Maintenance Superintendent, NAPS, Narora, Fax- 05734-222167 (ii) Maintenance Superintendent, RAPS, Rawatbhata, Fax- 01475-242060 23. GM (O&M) NR – I, PGCIL, New Delhi, Fax-011-26601079 24. GM (O&M), NR-II, PGCIL, Jammu, Fax-01951-237186 25. Chief Manager (TS), N.R.L.D.C, New Delhi, Fax- 011-26852747 26. GM(OS-NR), NTPC, Lucknow, Fax No. 0522-2305848 27. GM (OS) NTPC Ltd., Noida, Fax-0120-2410082, 2410068 28. DGM (Maintenance), SJVNL, New Shimla, Fax- 0177-2673283 29. DGM (O&M), THDC India Ltd., Tehri Garhwal, Fax No 01376-236305 30. Director (GM division), CEA, New Delhi, Fax-011-26109750 31. General Manager, APCLP, Fax No. 01251-266326

32. Director JPPVL, Fax- 0120-4516201/4609464/4609496 33. Assistant Vice President, BRPL, Fax- 39996055, 39999765 34. GM (Production), Jhajjar Power Ltd., Fax- 01251-270155 35. Managing Director, APL, Fax No. 0124-2555342

Summary record of discussions held in the 28th Protection Sub-Committee

meeting held on on 19.12.2014 at 10:00 hrs. at Ludhiana, Punjab

The list of participants is enclosed at Annexure-I.

Sh. R.K.Sharma, CE, PSTCL welcomed the participants to the 28th meeting of Protection Sub

Committee (PSC) and stated that it was their privilege to host the meeting. Citing the

importance of Protection Sub-Committee, he stated that it serves the platform for experience

sharing and discussing the issues for stabile and secure operation of the power system.

Welcoming the participants Smt. Shashi Prabha, Director (Tech.), PSTCL emphasized the need

to expedite rectification deficiencies observed during protection audit. She further added that

PSTCL was in the process of implementation of the islanding scheme and a stability study for

the same was being done by CPRI. She informed that PSTCL was replacing conventional

insulators with polymer insulators to avoid fog related tripping during winters. She requested the

participants to analyse the incidents in details and come out with remedial measures to enhance

the reliability of the grid.

Welcoming participants Sh. P.S. Mhaske, Member Secretary, NRPC stated that the inadequacy

and unhealthy protection systems continues to be an area of concern. He added that in

accordance with recommendations of the Enquiry Committee to analyse the causes of the grid

disturbances in July, 2012, third party protection audit was carried out by POWERGRID in

association with CPRI. However, progress of rectification of the discrepancies observed in the

protection audit was slow. He requested all the utilities to expedite activities on this front.

Similarly, the third part protection audit of intrastate transmission as per decision of NRPC also

need to be expedited.

He stated that as a follow up of one of the recommendations of Enquiry Committee on grid

disturbances that took place in July 2012, Ministry of Power had constituted a ‘Task Force on

Power System Analysis under Contingencies’ in December 2012. This task force had made

some important recommendations which inter-alia include relay settings & protection co-

ordination and creating & maintaining data base of relay settings. He requested all utilities to

formulate a time bound action plan for implementation of recommendations of this Task Force.

He stated that large numbers of trippings have occurred in Northern Region during the past

four months. Many of these trippings were in U.P. particularly at Agra, Sarnath, Anpara,

Gorakpur areas. He suggested that UPPTCL should review the protection in these areas to

avoid the tripping.

He further added that there was lot of delay in submission of reports of trippings with the results

that by the time they are analyzed they lose their relevance. There is a need for timely analysis

of the various trippings and corrective steps should be taken to minimize trippings.

He expressed concern at the non-availability of Bus bar protection in large number of

substations. The position is worse in Haryana, Rajasthan, UP and Punjab. He requested the

utilities to expedite the installation of BUS bar protection. In the end, he thanked Smt. Shashi

Prabha, Director (Tech.), PSTCL and team of officers from PSTCL for hosting this meeting and

for making the excellent arrangements.

A.1 Confirmation of minutes of 27th Protection Sub-committee The sub-committee confirmed the minutes of 27th meeting of Protection Sub- committee, held on 26th August, 2014 issued vide letter no. NRPC/OPR/107/01/2014 dated 02.12.2014. A.2 Follow up action on outstanding issues from previous meetings

A.2.1 Protection related issues at 400 kV switchyard of Mahatma Gandhi TPS

SE (O), NRPC stated that it was decided in 25th PSC that HVPNL and JPL would hold a separate meeting within a week to resolve the protection coordination relates issues. Further, they were requested to intimate gist of discussions to NRPC secretariat with a copy to NRLDC. Since the meeting was not held till 26th PSC meeting, it was decided that HVPNL will convene the meeting within a week with JPL and private transmission licensee operating the sub-station adjacent to Mahatma Gandhi TPS. No representative from JPL attended the meeting. It was decided that henceforth this agenda would be dropped.

A.2.2 Non-functional carrier-inter-trip feature

SE(O), NRPC stated that in the 23rd PSC meeting, BBMB had intimated that carrier-inter-trip feature (Carrier aided protection of transmission line) of following lines was not enabled due to faulty PLCC channels (at PSTCL and HVPNL ends). Status as updated in 27th PSC is as under:

Sr.No Transmission Line (220 KV)

This end Other end

Status as updated in 27th PSC

1 Jamalpur-Dhandari-I&II

BBMB PSTCL PLCC has been tested and found functional for 220 kV Jamalpur-Dhandari-I. For ckt-II material has been allocated and it would be completed by 31.01.2015.

2 Jalandhar-Butari

BBMB PSTCL PLCC has been tested and is functional.

3 Jalandhar-Jamsher-I&II

BBMB PSTCL PLCC has been tested and is functional.

4 Barnala–Lehra-Mohabbat

BBMB PSPCL Material has been allocated by PSTCL and it would be functional by 31.01.2015

5 Samaypur-Badshahpur BBMB HVPNL HVPNL informed that it would be functional by 31.03.2015

6 Samaypur-Palwal-I&II

BBMB HVPNL HVPNL informed that it would be functional by 30.06.2015

A.2.3 Non- availability/ defective PLCC link of STU Lines terminated at POWERGRID (NR-2) substations

POWERGIRD had submitted a list of sub-station in 22nd PSC meeting where PLCC was non-functional at other side. The list as updated in 28th PSC meeting is enclosed as Annex-II. It was noted that PLCC was still non-functional for links owned by PDD J&K and HVPNL. It was agreed that entities concerned would expedite restoration of PLCC links mentioned above.

A.2.4 Islanding scheme for Rajasthan and Haryana

A.2.4.1 SE (O), NRPC stated that in the 27th PSC meeting, RRVPNL was requested to reconsider its stand on inclusion of Mahi HEP in the islanding scheme. It was decided that RVPNL would carry out dynamic simulation studies with the help of CPRI and if simulation reveals that islanding would function well even with inclusion of Mahi HEP, RVPNL can go ahead with their proposal. RVPNL has agreed to carry out the dynamic simulation studies and submit the study report. Representative of RRVPNL informed that studies were yet to be carried out. SE (O), NRPC stated that there was already an islanding scheme meant for RAPP-A and RAPP-B and whether it was possible to operationalize the revised scheme excluding Mahi HEP in shortest possible time. Latter can be included in the scheme, if study results support the same. Representative of RVPNL informed that there had been a change the system configuration around RAPP area. SE(O), NRPC suggested that the issue could be discussed in a separate meeting to review the existing functional islanding scheme scheduled on 30.12.2014

A.2.4.2 SE(O), NRPC informed that HVPNL had submitted islanding scheme for the state. The

issue was discussed in the 26th meeting of PSC, wherein it was observed that difference in the estimated available generation and load in the island was too small and therefore the island, if formed, might not survive. Further it was requested that HVPNL might discuss the scheme with NTPC as their Faridabad gas station was part of the proposed islanding scheme. HVPNL had agreed to review the scheme. He added that it was agreed in 27th PSC meeting certain suggestions were made for proposed islanding scheme. He sought to know the progress in the matter. Representative of HVPNL informed that changes suggested by PSC were under consideration. SE(O), NRPC requested HVPNL to expedite the same so that scheme could be approved in the next NRPC meeting. SE(O), NRPC informed that a meeting was held on 27th November, 2014 at NRPC Sectt., New Delhi to review the islanding schemes for Punjab. It was decided that PSTCL will implement the scheme envisaged for Lehra Mohhabat and Bhatinda TPS at first instance. Based on the experience of the above, the islanding scheme meant for Ropar TPS could be implemented later.

7 Samaypur-Palli-I&II

BBMB HVPNL It has been tested and found ok.

8 Bhiwani-Bapora-I&II

BBMB HVPNL Radial feeders. Not required.

PSTCL informed that stability study for the scheme was being carried out by CPRI and report of the same would be available by 31.12.2014. Thereafter, procurement would start. PSTCL informed that scheme would be completed by 31.03.2015

A.3 Progress of rectification of deficiencies observed/improvements suggested in

Basic Protection Audit.

The status of rectification of rectification of deficiencies observed in basic protection audit carried out by POWERGRID & CPRI is to be submitted on monthly basis. The status of progress of rectification of deficiencies was given in Annex-II of the agenda. The abstract in regard to expected completion time of rectification of protection related deficiencies by utilities is under:

S.No. Utility No. of sub-stations

covered under BPAExpected Completion Remarks

1 UPPTCL 21 March, 2015 2 UPRVUNL 4 November, 2014 3 RRVPNL 8 May, 2015

4 RRVUNL 2 Suratgarh – Rectification work completed. except time synchronization of newly retrofitted relays. Kota -March 2015

5 HVPNL 1 Completed. Completed.

6 HPGCL 3 March, 2015 7 PSTCL 3 March, 2015 8 PSPCL 1 December, 2014

PSPCL needs to submit latest status of rectification observed during BPA with target completion.

9 DTL 1 December, 2014 10 HPSEB Ltd. 1 November, 2014 11 PTCUL 2 November, 2014 12 UJVNL 1 No target completion

indicated. Status of deficiencies observed during BPA is submitted on 15.10.2014 but target of completion not given.

13 PDD, J&K 3 Status of progress is not submitted. Target completion not known.

Status not known.

14 BBMB 7 March, 2015 15 POWERGRID 46 POWERGRID (NR-I) &

(NR-II) completed though some PLCC issues are yet to be resolved at remote end with other utilities.

POWERGRID is pursuing with the concerned utilities.

16 NTPC 10 Other by December, 2014 except Singrauli STPS (June, ’15)

Vindhyachal STPP & 400/220 kV Dadri Sub-station- Completed.

17 NHPC 8 Tanakpur- December, 2014; Chamera-I-Feb.2015; Dulhasti–October, 2015.

Uri-I, Salal, Chamera-II, Chamera-III & Dhauliganga –Completed. However, observations of BPA needs to comply.

18 SJVNL 1 December, 2014. 19 THDC 1 Completed. 20 NPCIL 1 October, 2014.

The corrective actions for smooth operation of PLCC system were required to be taken by POWERGRID, UPPTCL and RRVPNL. The status was enclosed as Annex-III of the agenda.

SE(O), NRPC requested utilities to expedite the rectification of deficiencies related to PLCC.

A.4 Third Party Protection Audit by the Protection Experts for intra-state system/ balance system not covered in Basic Protection Audit.

Based on information submitted by representatives of various utilities, the status in this regard is summarised status was enclosed as Annex-IV of the agenda.

It may be seen that

Some of the Utilities like RRVPNL, PSTCL, Rosa Power Ltd., PSPCL UPPTCL, and UPRVUNL & THDCIL have placed order for protection audit to CPRI and work is already underway. These utilities were requested to share draft/final report with Protection sub-committee, as and when available. Some other Utilities like UJVNL have also shown inclination to award this work to CPRI. Utilities are requested to update the status of work by CPRI.

UPPTCL and PSTCL informed that the report of TPPA is expected by 31.12.2014. Action has already been initiated for the rectifications of the deficiencies.

Protection Audit of sub-station identified by HVPNL, DTL, HPSEB, PTCUL, NHPC, APCPL, HPGCL, and NPCIL has been carried out by the teams of protection experts constituted by NRPC. The summary of findings/shortcomings was enclosed as Annex-V of the agenda. Utilities were requested to update the status of rectification of shortcomings observed.

RVPNL and BBMB have submitted the report of protection audit carried out by CPRI. Their executive summary with suggestions was enclosed as Annex-VI of the agenda.

UT Chandigarh had requested for constitution of team of experts amongst the pool of protection expert for the TPPA of their 220 kV sub-station and team for the same had been constituted.

PDD J&K had submitted list of 02 nos. of sub-station for TPPA.

RRVPNL informed that one of the recommendations of CPRI was that in place of VRLA batteries, conventional lead acid batteries should be preferred as VRLA are very sensitive to temperature and batteries fails when air conditioning is not proper. After deliberations, it was decided that the above mentioned recommendation should be treated as suggestion and not mandatory requirement. Utilities should procure batteries on the basis of their own experience and requirement. However, the utilities should ensure that batteries should be reliable. BBMB informed that CPRI has suggested for dedicated EL facility for each sub-station. However, they were having EL facility in the numerical relays also. SE(O), NRPC opined that as per CEA regulation, EL facility at sub-station should be available and functional. It was agreed that event logging through Numerical Relays meets the requirement of CEA regulations. On the issue of provision of Bus Bar protection , BBMB also informed that there are certain conditions where Bus Bar Protection is not required like if nos. of feeders are less than five or there is only one bay. These conditions were prevailing in some of their our sub-stations, because of which they were not installing the Bus Bar Protection.

SE(O), NRPC stated that as per CEA grid connectivity standard, there should be Bus Bar Protection for all sub-station of 220 kV and above. If there is really a technical ground for not having Bus Bar Protection for the above mentioned conditions then BBMB should bring an agenda note in the next protection sub-committee meeting. After due deliberation if PSC agrees on the issue then the matter would be referred to CEA requesting the amendments in the regulations.

A.5 Status of Bus Bar protection

During earlier PSC meetings, utilities were requested to update the status of Bus Bar Protection available with NRPC secretariat. Updated status enclosed as Annex-II. Utilities were requested to expedite the implementation of Bus Bar Protection and submit the information. NRLDC has submitted a list of 765 kV, 400 kV and 220 kV sub-stations along with the information required about the details of bus bar protection. The format having the name of the sub-stations is enclosed as Annex-VIII of the agenda. Utilities were requested to submit the information to NRLDC with a copy to NRPC secretariat.

A.6 Setting of out of step protection RVPNL informed that it has been observed that one of the relay on the Chhabra-Bhilwara line at Bhilwara end had mal operated. The relay detected the power swing and should have issued trip command after 2000 msec but command was issued just after 250 msec. Setting of out of step and stable setting is available in the range of 1 to 255 steps in MICOM Distance protection relays. Normally settings adopted as “1” for both features which need to be revised to avoid undesired operation. RVPNL suggested that out of step setting & stable swing setting may be adopted as 2 & 8 respectively to avoid unnecessary tripping. This setting is based on the experience of RVPNL. SE(O), NRPC requested RVPNL to share the setting and trip file with POWERGRID. POWERGRID was requested to study the same and give their opinion in the next PSC meeting.

A.7 Implementation of Recommendations of the Task Force

SE(O), NRPC informed that as a follow up of one of the recommendations of Enquiry Committee headed by Chairperson, CEA on grid disturbances that took place on 30th and 31st July 2012, Ministry of Power had constituted a ‘Task Force on Power System Analysis under Contingencies’ in December 2012. The Task Force had submitted its report in August 2013. In a meeting taken by Secretary (Power), GoI on 11.03.2014, it was decide that the report be given wide circulation and its recommendations be implemented in a time bound manner. The report of the Task Force as also Guidelines for Protection settings recommended by the Task force have been uploaded on NRPC website (links http://www.nrpc.gov.in/reports/other/taskforce_analysis.pdf and http://www.nrpc.gov.in /reports/other/ps_guidelines.pdf ). Member Secretary, NRPC vide letter dated 31st July 2014 (copy enclosed as Annex-VI of the agenda) had requested members of NRPC to initiate action for implementation of recommendations of the Task Force. Further, it was also agreed in the above mentioned meeting taken by Secretary (Power), GoI that data regarding settings of relays shall be compiled by the CTU and

STUs in their respective network and furnished to RLDC and SLDC respectively with a copy to RPC for maintaining the database. The database shall be kept updated and verified during the audit. SE(O), NRPC informed that it was agreed in 27th PSC meeting that CTU would design a format to collect the database and this format may also be forwarded to the SLDCs so as to bring the uniformity as far as possible. He further added that RVPNL has submitted the information about relay setting in a excel based format. It was decided to forward the same format to POWERGRID and based on the inputs of POWERGRID a format would be designed to preparing a database of protection relays.

A.8 Protection relay setting guidelines for 765 kV, 400 kV and 220 kV transmission

lines SE(O), NRPC informed that the sub-committee constituted by above mentioned Task Force for examining philosophy of relay and protection coordination has also given the Protection relay setting guidelines for 765 kV, 400 kV and 220 kV transmission lines. He added that it was decided in 27th PSC meeting that to review the uniform philosophy agreed by NRPC in the light of report of the subcommittee constituted by task force a group has been constituted by PSC. Accordingly a group has been constituted. Details of the same were enclosed as Annex-VIII of Agenda.

Members noted the status.

A.9 Data regarding blast/failure of CTs and replacement plan for older CTs Information regarding CT blast/failures during last five years (i.e. on or after 01.04.2009) and details of existing CTs was sought vide letter dated 15.07.2014 from all STUs and GENCOs utilities. The information was to be submitted in the prescribed format. BBMB, DTL, JPL. IPGCL/PPCL, PTCUL, HPGCL, UJVNL, NHPC, NTPC, Lanco Anpara Power Ltd., APL, RRVPNL, UPPTCL and Rajwest Pvt. Ltd., have submitted the requisite information. All other utilities were requested to submit the information by 15th Dec 2014.

A.9 PLCC and protection issues related to DTL

POWERGRID informed that following issues were pending with DTL: S.

No. Name of Line Details of PLCC

A. Ballabhgarh S/s

1. 400kV Ballabhgarh-Bamnauli-I

Some portion of overhead transmission line had been replaced with underground cable at Bamnauli end. Attenuation of PLCC signal was very high due to cable. PLCC was frequently failing in B’Garh-B’nauli line. Necessary measures needed to be taken up for rectification of same.

2. 400kV Ballabhgarh-Bamnauli-II

The Protection related issues are as follows:

S. No.

Name of Line Details of distance protection relay

A. Ballabhgarh S/s

1. 400kV Ballabhgarh-Bamnauli-I REL521 – Both Main-1 & Main-2 relay were of same make/algorithm

2. 400kV Ballabhgarh-Bamnauli-II REL521 – Both Main-1 & Main-2 relay were of same make/algorithm

B. Mandola S/s3. 220kV Mandola - Narela-I QUADRAMHO – Static relay needs to

be retrofitted with numerical relay 4. 220kV Mandola - Narela-II QUADRAMHO - Static relay needs to

be retrofitted with numerical relay

Representative of DTL informed that LoA for the relay meant for 400kV Ballabhgarh-Bamnauli-I had been placed and same was expected by 31.03.2015. DTL was requested to submit the action plan for all these works within 15 days.

A.11 Auto Re-closure issues related to NTPC, Unchahar

Representative of POWERGRID stated that Auto-Reclosure scheme was not functional at NTPC, Unchahar end for 220kV Lines connected to Rai Bareilly & Kanpur Sub Station.

S. No.

Name of Line Details of Auto Re-closure

A. Rai Bareilly S/s 1. 220kV Rai Bareilly-Unchahar-I Auto re-closure scheme was not

functional at Unchahar end. 2. 220kV Rai Bareilly-Unchahar-II 3. 220kV Rai Bareilly-Unchahar-III B. Kanpur S/s 1. 220kV Kanpur-Unchahar-I Auto re-closure scheme was not

functional at Unchahar end. 2. 220kV Kanpur-Unchahar-II 3. 220kV Kanpur-Unchahar-III 4. 220kV Kanpur-Unchahar-IV

Representative of NTPC informed that action had already been initiated and same would be completed by June, 2015.

A.12 PLCC and Auto Re-closure issues related to UPPTCL Representative of POWERGRID stated that there were various lines of UPPTCL wherein PLCC panels and auto re-closure schemes were not in working condition due to which frequent tripping of lines on transient faults were taking place. Status and problem of PLCC and Auto re-closure is detailed below:

S. No.

Name of Line Details of

PLCC Details of Auto

Re-closure

Status submitted during the meeting

A. Allahabad S/s 1. 220kV Allahabad-Rewa Road-I

PLCC link is through but fail frequently due to not availability of wave trap at Rewa Road end , UPPCL is to be installed Wave trap

A/R is not functional Wave Trap was being procured and scheme would be functional by March, 2015

2. 220kV Allahabad-Rewa Road-II

A/R is not functional

B. Kanpur S/s 1. 220kV Kanpur-Mainpuri PLCC panels are

not available A/R is not functional

2. 220kV Kanpur-Naubasta A/R is not functional 3. 220kV Kanpur-Panki-I A/R is not functional 4. 220kV Kanpur-Panki-II A/R is not functional 5. 220kV Kanpur-Orai A/R is not functional

C. Mainpuri S/s 1. 220kV Mainpuri-Etah PLCC panels are

not available A/R is not functional

2. 220kV Mainpuri-Mainpuri(UP)-I A/R is not functional 3. 220kV Mainpuri-Mainpuri(UP)-I A/R is not functional 4. 220kV Mainpuri-Ferozabad A/R is not functional

D. 400/220kV Lucknow S/s 1. 220kV Lucknow-Sitapur A/R is not functional PLCC available but

tele-protection and auto reclosing was not working as features not available in the relay

2. 220kV Lucknow-Chinhat PLCC is not functional

A/R is not functional PLCC and A/R was functional. Testing was required.

D. Gorakhpur S/s 1. 220kV Gorakhpur-Barhua PLCC is not

functional A/R is not functional

2. 220kV Gorakhpur-Basti PLCC panels are not available

A/R is not functional

E. Merrut S/s 1. 220kV Merrut-Modipuram-I A/R is not functional 2. 220kV Merrut-Nara A/R is not functional PLCC and A/R was

functional. Testing was required.

3. 220kV Merrut-Modipuram-II A/R is not functional New Relay was being arranged for making it functional.

4. 220kV Merrut-Simbhawali A/R is not functional PLCC and A/R was functional. Testing was required.

5. 220kV Merrut-Shatabadi Nagar A/R is not functional By 31.12.2014 it would be made functional.

6. 220kV Merrut-Gajraula PLCC is not functional

A/R is not functional Within 15 days it would be functional

7. 220kV Merrut-Nehtaur A/R is not functional Within 15 days it would be functional

F. Rai Bareilly S/s 1. 220kV Rai Bareilly-Chinhat PLCC is not

functional A/R is not functional PLCC and A/R was

functional. Testing was required.

2. 220kV Rai Bareilly-Sitapur PLCC panels are not available

A/R is not functional Protection panels had been arranged for 220kV Rai Bareilly-Sarojininagar line, which was being installed.

PSC requested members to expedite the works to make PLCC and A/R functional.

A.13 Maintenance of PLCC in case of LILO of Line

Representative of POWERGRID emphasized on the need to formulate a policy regarding maintenance of PLL in case of LILO. He stated that for technical suitability, the PLCC panel of one station has to be shifted to the station where LILO of line has been done.

As a typical case, both ends of above line belong to different utilities. Ownership of

PLCC panels at each end belong to respective utility therefore major/minor maintenance are being taken care by respective utility. In case of LILO of line by some other utility, the PLCC panels at one end, suppose End-A has been shifted to End-C for technical suitability. Utility at End-C is supposed to provide new PLCC panels for Line A-C at End-A.

Under such circumstance, the Panels of End-A has been shifted to End-C and new PLCC panels has been supplied at End-A by Utility at End-C. POWERGRID proposed that after successful commissioning of PLCC panels in Line A-C and Line B-C, the PLCC panels will be maintained by utility at their respective end. However if existing PLCC panels are very old & obsolete and OEM (Original Equipment Manufacturer) is not providing any spare/service support, old panel needs to be replaced with new panels before LILO of line and after up-gradation of old panels, subsequent maintenance & up-keeping of spares will be taken care by utility end where PLCC panels are installed. After, deliberations following decisions were taken by PSC: 1. In case of shifting of the PLCC from one sub-station to other, the utility executing the

LILO work would ensure that the panel is not older or obsolete and if it is so then new panel would be installed at the sub-station.

2. Regular and day-to-day maintenance of the PLCC panels would be carried by the

organization which owns the substation. It was also agreed that these guidelines would be followed by all utilities in the Northern Region after the approval of NRPC.

A.14 Rectification of faulty Direct Trip schemes at NTPC, Dadri DTL informed that 400 kV Harsh Vihar substation of DTL was energized through 400kV Dadri-Harsh Vihar Ckt 1&2. Since its commissioning, there have been problems in the protection schemes. Unwanted trippings have taken place on these circuits on several occasions. Some of the incidents are detailed below:- A. Tripping on 14-09-2014 and 8-10-2014 There was fault on Harsh Vihar-Dadri Ckt-2, but Ckt-1 relay from Dadri sent wrong Direct trip command resulting in wrong tripping of Ckt-1 at Harsh Vihar. Subsequently, the faulty relay at Dadri end was replaced by NTPC. B. Tripping on 16-11-2014 at 21:39 Hrs

Though there was no fault in the line but a Direct trip command was received on Ckt -1 at Harsh Vihar through Channel-2 resulting in unwanted tripping of the line. C. Direct trip command received on Ckt-1 ON 17-11-2014 at 00:34 Hrs Circuit-1 was OFF due the above incident, but Direct trip command was received again on the circuit. This happened repeatedly and the counter progressed by 34 counts. As

the DT command was being received continuously, so Channel-2 was made OFF and the Circuit was charged at 00:54 Hrs on 17-11-2014. The matter was taken up with M/s ABB. DTL representative had visited Dadri along with ABB Engineer on 27-11-2014 and the reason of Direct Trip send was investigated jointly by DTL, NTPC and ABB Engineers. It was observed that there was problem in the control wiring circuit of 400kV Circuit Breaker (Manual trip circuit). The problem was required to be rectified by NTPC Dadri but till that day they had not confirmed about the action taken by them to rectify the problem. NTPC informed that problem had been rectified and testing had also been carried out.

A.15 SPS testing of 765 kV Agra-Gwalior line: SE(O), NRPC informed that it has been decided to carry out mock testing of SPS for 765 kV Agra-Gwalior for automatic load shedding action in Northern Region on 24th December, 2014. Information in this regard to the concerned utilities had been forwarded vide letter No. NRPC / OPR /107/03 / 2014 dated 10.12.2014. Copy of the letter was enclosed as Annex-IX of the agenda. It was requested that SLDCs/Control Centres of Rajasthan, Haryana, Uttar Pradesh, Punjab and BBMB should forward the name and contact details (including mobile, e-mail ID etc.) of the officers coordinating the testing at sub-station. Members agreed for the same.

B. Tripping events

PSC-28/T/1: Multiple Elements tripping at 400kV Anpara-B TPS on 10th Aug 2014 at 10:02hrs

Event category: GD-1 Generation loss: 370 MW Loss of load: Nil Data Summary received to NRLDC:

Description Utilities Present Status Remarks

Availability of Digital Data (SCADA Data) Not Available

DR/ EL UP Not Received Flag Details only

Preliminary Report UP Received After 24hrs

Detailed Report UP Received After 24hrs

Description Fault Info Remarks

Fault Clearance Time 120ms As per PMU data

Phase of the Fault Red‐Phase As per PMU data

Description Clauses Utility Remarks

Violation of Clauses IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; UP

CEA Grid Standard 15.3; 43.4.D of CEA Technical Standard for Construction of Electrical Plants and

Electric Lines; CEA Grid Standard 15.4

UP

Based on above information NRLDC representative briefed the house about the event:

1. At Anpara TPS, generating unit no-4 was running at about 370 MW with all the

parameters normal. Load was low on account of poor and wet coal. 2. At 10:02 hrs, 400kV Bus-Bar differential Protection of Anpara-B TPS Bus-I operated

which resulted in tripping of generating unit no.4, 400kV Anpara-B TPS Bus Coupler, 400kV Anpara-B TPS Bus Section-I and 400kV Anpara-Sarnath line (L-5).

3. On investigation, it was found that R-phase unit of generator transformer of unit no. 4 was damaged. Following are the list of tripped elements:

• 500MW Generating unit number 4 • 400kV Bus Sectionalizer between Anapara-A TPS & Anpara-B TPS • 400kV Anpara-Sarnath ckt • 400kV Bus Coupler

4. Connectivity Diagram:

5. Max dip in R-phase. Time of fault was 10:02:36.280hrs & fault duration was ~120ms. 6. Details of the tripping received from UP is given below:

Remedial Action to be taken (As per UP Report): At Anpara TPS, the reason of damage of R-phase of generator transformer to be investigated in detail and remedial action be taken so as to prevent/avoid such incidences in future

No representative from UPRVUNL attended the meeting. It was informed by U.P. SLDC that internal enquiry committee was set up for outage of GT(Generator Transformer) at Anpara-B TPS. PSC Conclusion:

1. There was fault in Generator Transformer of unit number 4 at Anpara-B TPS. Fault clearance time was ~100ms which corroborated that In this case Bus Bar differential protection may have wrongly operated at Anpara-B TPS.

2. Preliminary & Detailed reports had been received. It was mentioned in the report that “Printouts of disturbance recorder/event logger are not available”.

PSC Recommendations: 1. Bus Bar Protection at Anpara-B TPS needs to be checked & corrected. (Action:

UPRVUNL; Time Frame: 15 days) 2. Timing of LBB protection (100ms instead of 200ms) & operation of LBB

protection at Anpara-B TPS needs to be checked & corrected. (Action: UPRVUNL; Time Frame: 15 days)

3. GT protection operation needs to be looked into. (Action: UPRVUNL; Time Frame: 15 days)

4. Availability of digital signal also needs to be ensured. (Action: UPRVUNL; Time Frame: 15 days)

5. UPRVUNL representative(s) should attend the meeting in future so that event could be discussed properly. SLDC-UP may write a letter to UPRVUNL for attending the PSC meeting in future.They should also send the remedial action report of the incident within 15 days.

6. Software for extraction of DR/EL to be made available at each sub-station. (Action: UPPTCL, Time Frame: 1 month)

PSC-28/T/2: Tripping of all the running units of 400kV Rampur HEP on 12th Aug 2014 at 16:28hrs




DR/ EL SJVNL Not received

Preliminary Report SJVNL Not received

Detailed Report SJVNL Not received


Fault Clearance Time Not Applicable As per PMU data

Phase of the Fault No fault As per PMU data


Violation of Clauses IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; SJVNL

CEA Grid Standard 15.3; 43.4.D of CEA Technical Standard for

Construction of Electrical Plants and Electric Lines;

CEA Grid Standard 15.4

SJVNL


1. Rampur has connectivity of D/C with Nathpa Jhakri & Nallagarh. It’s have 6number of units of 68.67MW. Total generating capacity is 412MW. 1500MW Nathpa Jhakri HEP is in upstream of Rampur HEP. Water is available to Rampur HEP via tunnel at tail race of Natjpa Jhakri HEP.

2. It was reported that Tandem Operation Signal received at Rampur HEP and all the running units of Rampur HEP tripped.

3. Tandem Operation Signal has wrongly operated. As per PMU data there was no fault in the system.

4. Digital data of 400kV Rampur HEP station is not available at NRLDC. No representative from SJVNL attended the meeting.

PSC Conclusions:

1. Preliminary Report, DR/EL & detailed report was awaited from SJVNL. 2. SJVN Ltd was requested to attend the meeting in future so that event could be discussed

properly. SJVN Ltd was also requested to submit the detailed report of the incident within 15 days

3. Availability of digital data of Rampur HEP needs to be looked into. 4. Wrong operation of Tandem operation scheme needs to be looked into.

PSC Recommendations:

SJVN Ltd to check the Tandem operation scheme and submit their findings to NRPC with copy to NRLDC. PSC-28/T/3Multiple Element tripping at Agra(UP):

Details of multiple element tripping at Agra(UP) station is given below:

Sr. No.

Date of Event

Time of Event Tripped Element

Fault Clearing Time

Event Category Loss

1 20.08.2014 11:10hrs

315MVA ICT‐3220kV Agra‐Samsabad220kV Agra‐Sikandra D/C220kV Agra‐Gokul220/132kV 160MVA ICT‐2220kV Bus Coupler

NA (No fault in the system) GD‐1

Load Loss:437MW

2 28.08.2014 13:34hrs

400 KV Agra (UP)‐Agra (PG) D/C400/220 KV, 315 MVA‐I at Agra 400/220 KV, 315 MVA‐II at Agra400/220 KV, 500 MVA at Agra400 KV Agra‐Unnao line400 KV Agra‐Muradnagar line220 KV Agra‐Gokul220 KV Agra‐Hathras220 KV Agra‐Shamsabad220 KV Agra‐Sikandra D/C220 KV Sikandra‐Bharatpur220kV Sikandra‐Auraiya D/C 400ms GD‐1

Load Loss: 754MW

3 12.09.2014 11:55hrs

400 KV Agra (UP)‐Agra (PG) D/C400kV Agra‐Unnao400kV Agra‐Muradnagar400/220kV 315MVA ICT‐1&3400/22‐kV 500MVA ICT 80ms GD‐1

Load Loss: 469MW

4 18.09.2014 17:56hrs 400/220kV 315MVA ICT‐1&3400/22‐kV 500MVA ICT 2200ms GD‐1

Load Loss: 1137MW

5 11.11.2014 11:43hrs

400 KV Agra (UP)‐Agra (PG) D/C400/220 KV, 315 MVA‐I at Agra 400/220 KV, 315 MVA‐II at Agra400/220 KV, 500 MVA at Agra400 KV Agra‐Unnao line400 KV Agra‐Muradnagar line

NA (No fault in the system) GD‐1 581MW

NRPC had constituted a group for analysis of the incidents at Agra. The group has submitted its report, which is available on NRPC website (www.nrpc.gov.in/reports/other/Agra-UPPTCL.pdf.)

PSC-28/T/4Multiple element tripping at 400kV Kashipur HEP on 20th Aug 2014 at 13:41hrs

Event category: GD-1 Generation loss: Nil Loss of load: 330 MW Data Summary received to NRLDC:



DR/ EL

Uttrakhand Received At the time of meeting

UP Received (only flag

details) Partial

Preliminary Report Uttrakhand Received At the time of meeting

Detailed Report Uttrakhand Not received



Phase of the Fault Max dip in Y‐

phase As per PMU data


Violation of Clauses

IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3;

Uttrakhand, UP 1. DR/EL, Preliminary report didn’t provide

within 24hrs


Electric Lines; CEA Grid Standard 15.4 CEA Grid Standard 3.1.e

Uttrakhand, UP 2. Fault Clearance time more than 100ms for

400kV system


1. Kashipur is connected with 400kV Moradbad & Rishikesh line. It is also connected with 220kV Pantnagar and also connected with Uttrakhand system at 132kV level.

2. Phase to phase fault occurred in 400kV Kashipur-Rishikesh line. 400kV Kashipur-Rishikesh line along with Kashipur-Moradabad line tripped.

3. Fault clearance time as per PMU data was ~1000ms. Max dip in Y-phase. 4. 400kV Kashipur-Moradabad line tripped in zone-3 from Moradabad end. 5. 400kV Kashipur-Rishikesh line tripped with time delay. As per DR details of Rishikesh

end, line tripped from Rishikesh end in 1000ms. Kashipur end relay also sense fault in zone-2 & 3 but didn’t send the trip command to breaker at Kashipur end.

6. Digital data status was not available at NRLDC.

Representative from PTCUL has informed that fault was in 400kV Kashipur-Rishikesh line and Kashipur end also tripped. Delayed clearance of fault may be due to static nature of Main-2 Protection. Same has been replaced in November. Flag details from 400/220kV Moradabad station is given below:

PSC Conclusions: 1. Phase to phase fault occurred in 400kV Kashipur-Rishikesh line. 400kV Kashipur-

Rishikesh line didn’t trip from Kashipur end. Rishikesh end breaker also tripped in zone-

3. Due to continuous feeding of fault from Moradbad end, 400kV Moradbad-Kashipr line also tripped in zone-3.

2. Fault Clearance time was ~1000ms. It was due to non-operation of protection at kashipur end & delayed operation at rishikesh end.

3. DR has been submitted by Uttrakhand & Uttar Pradesh but detailed report from Uttrakhand was awaited.


1. Distance Protection of Kashipur end & Moradbad to be checked & corrected. (Action: PTCUL; Time Frame: 15 days)

2. Detailed Report from Uttrakhand to be submitted within 15days 3. Availability of digital data to be ensured. (Action: PTCUL; Time Frame: 15days)

On 1st Sep 2014 at 14:35hrs, 400kV Kashipur-Rishikesh & Kashipur-Moradabad again tripped on fault. Fault Clearance time was ~2000ms & maximum dip was in Blue-phase. Representative from PTCUL informed that on 1st of Sep 2014, fault was in 220kV section at Kashipur station. 220kV end breaker couldn’t open, Protection at 400/220kV ICT’s also couldn’t respond. It might have resulted into tripping of 400kV lines from remote end in zone-3.

Multiple Element tripping at 220kV Samaypur station on 27th Aug 2014 at 23:22hrs Event category: GD-1 Generation loss: Nil Loss of load: 350 MW Data Summary received to NRLDC:



DR/ EL BBMB Not received

Haryana Not received

Preliminary Report BBMB Received After 24hrs


Detailed Report BBMB Not received




Phase of the Fault Red‐phase As per PMU data


Violation of Clauses IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; Haryana, BBMB



Haryana, BBMB

Based on above information NRLDC representative briefed the house about the event::

1. In antecedent condition 220kV Samaypur-Charkhi Dadri ckt connected on Bus-I at 220kV samaypur station. Antecedent connectivity of elements is mentioned below:

2. Y-phase CT of 220kV Samaypur-Charkhi Dadri line at 220kV Samaypur station bursted &

caught fire. It resulted into operation of Bus Bar Protection for Bus-I and all the elements connected to Bus-I of 220kV samaypur station tripped. List of the tripping elements is given below:

3. Fault time: 23:22:53.840hrs, fault is observed in Y-phase with voltage dip~32kV. Fault

duration was ~80ms. 4. As per NR SoE, it seems all the feeders tripped almost at the same time except charkhi

dadri end of 220kV Samaypur-Charkhi Dadri ckt. This ckt tripped at 23:22:54.033hrs from Charkhi dadri end i.e. slight voltage dip shown in PMU data.

5. As per SoE, 220kV Samaypur-Ballabgarh ckt-3 also tripped. In antecedent condition this ckt didn’t connect to Bus-I. Sequence of events available at NRLDC is given below:

PSC Conclusions: 1. Y-phase CT of 220kV Samaypur-Charkhi Dadri line at 220kV Samaypur station burst &

caught fire. It resulted into operation of Bus Bar Protection for Bus-I and all the elements connected to Bus-I of 220kV Samaypur station tripped.

2. Operation of Bus Bar Protection was correct operation but fault clearance time of 660ms needs more clarity.

PSC Recommendations: 1. Tripping of 220kV Ballabgarh-Samaypur ckt-3 was observed in SoE but same was not

connected at Bus-1 and also not reported by BBMB. BBMB may investigate this aspect and report. (Action: BBMB; Time Frame: 15days)

2. Delayed Clearance of fault needs to be looked into and rectified. (Action: BBMB; Time Frame: 15 days)

3. Delayed clearance of fault from Charkhi Dadri end needs to be looked into and rectified. (Action: BBMB; Time Frame: 15days)

PSC-28/T/5Tripping of 220kV Auraiya-Malanpur & Auraiya-Mehgaon ckt on 28th Aug 2014 at 01:37hrs

Event category: GD-1 Generation loss: Nil Loss of load: 350MW in WR region Data Summary received to NRLDC:



DR/ EL NTPC Received After 24hrs

Preliminary Report NTPC Received After 24hrs

Detailed Report NTPC Received After 24hrs






IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; NTPC



CEA Grid Standard 15.4 CEA Grid Standard 3.1.e

NTPC


1. 220kV Auraiya-Malanpur & 220kV Auraiya-Mehgaon tripped on R-phase to earth fault. 2. Max dip in Red phase and fault persisted for 6000ms (01:37:01.600hrs to

01:37:07.600hrs). 3. Delayed clearance of fault from Auraiya, Malanpur & Mehagaon end. 4. It seems from PMU data that some load loss has been occurred in the system. Rise in

frequency of ~0.05Hz observed, indicating load loss~250MW in the grid. 5. Sequence of Event didn’t capture in NR SoE. 6. As per WRLDC report At 01:37hrs, R-phase to earth fault occurred in 220kV Auraiya-

Malanpur line due to R-phase disc flash over at location no. 300. The line has tripped from Auraiya end, but due to problem in Malanpur end breaker, fault was continuously fed to other ckts. As LBB protection was not available at Malanpur station, It resulted into multiple elements tripping in WR along with tripping of 220kV Auraiya-Malanpur & Auraiya-Mehgaon line. 220kV Auraiya-Mehgaon line tripped from Auraiya end on back up earth fault protection. This event has resulted in blackout at Malanpur & Mehgaon S/s and radial connected load centers causing 350MW load loss in WR. Sequence of Event is given below:

Representative from NTPC informed the details of the tripping as below-

1. Fault was in 220kV Auraiya-Malanpur line at 55kM from Auraiya end. This line tripped in zone-1 from Auraiya end. Line didn’t auto-reclosed as auto-recloser in the line was not functional. A joint meeting is scheduled to be held on 22nd Dec 2014.

2. As fault was not cleared from Malanpur end, 220kV Auraiya_Mehgaon line tripped from Auraiya end on backup earth fault protection.

3. Delayed Clearance of fault was due to non-clearance of fault at Malanpur end

PSC Conclusion: 1. It was concluded from the discussion that fault was in R-phase of Auraiya-Malanpur line.

Line tripped from Auraiya end but due to non-opening of breaker at Malanpur end, fault was continuously fed through 220 kV Auraiya-Mehgaon lien & this line tripped from Auraiya end on back earth fault protection.

2. Delayed fault clearance at inter-regional boundary is a serious threat to the grid security.

3. The protection coordination observed during the tripping is not adequate which is observed with fault clearance time exceeding 6 seconds.

4. Fault clearance time was ~6000ms. Load loss was in Western Region. 5. Auto-recloser in 220kV Auraiya-Malanpur & Auraiya-Mehgaon line was not operational. 6. DR timing of Auraiya end of 220kV Auraiya-Malanpur & Auraiya-Mehgaon line was not

time synchronized. 7. NTPC to make sure availability of the digital SCADA data to the NRLDC.

Protection Committee Recommendations-

1. Availability of digital data to NRLDC needs to be ensured by NTPC (Action: NTPC; Time Frame: 7 days)

2. Time synchronization of DR of 220kV Auraiya-Malanpur & Auraiya-Mehgaon line to be checked & corrected (Action: NTPC; Time Frame: 7 days)

3. Auto-recloser in 220kV Auraiya-Malanpur & Auraiya-Mehgaon line to be checked & corrected. NTPC may also furnish the outcome of the joint meeting with MPPCL. (Action: NTPC, MPPTCL; Time Frame: 7days)

4. Protection coordination needs to be checked & corrected. (Action: NTPC, MPPTCL; Time Frame: 7days)

It was requested to the utilities to submit .dat & .cfg file for proper analysis of the events.

PSC-28/T/6Multiple Element tripping at 400/220kV Sarnath station on 30th Aug 2014 at 09:43hrs Event category: GD-1 Generation loss: Nil Loss of load: 228MW Data Summary received to NRLDC:



DR/ EL UP Not received Only Flag Details

Preliminary Report UP Received Yes

Detailed Report UP Received Yes


Fault Clearance Time No Fault As per PMU data

Phase of the Fault Not Applicable As per PMU data



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; UP

CEA Grid Standard 15.3; 43.4.D of CEA Technical Standard for Construction of Electrical

Plants and Electric Lines; CEA Grid Standard 15.4

UP


It was informed by UPPTCL site, that at 400kV Sarnath UP S/S, 400/220kV 315MVA ICT-III tripped on over current protection and ICT-1 tripped on resultant over loading.

It was informed that over current setting for electromechanical relay is 500A however for numerical relay it was ~ 455A or 300MW (full load current).

No fault observed through PMU data. Rise in the frequency was ~0.08Hz As per CBIP manual on protection of ICT, over load protection is for alarm only not for

tripping. Tripping would be on winding temperature high. Flag details is given below:

Remedial Action taken by UP:

At 400 KV S/S Sarnath, the reason of tripping of 315 MVA, ICT-III on over current protection investigated in details and it was found that sensitive setting of over current resulted into tripping of ICT’s. Same has been replaced as given above. One 400/220kV, 500MVA ICT is in commissioning stage at 400/22-kV Sarnath station. It

would be come into system till Jan 2015. After that over load problem may not be persisted at Sarnath station.

PSC Conclusion: 1. At 400kV Sarnath UP S/S, 400/220kV 315MVA ICT-III tripped on over current protection

due to sensitive over current setting of ICT-3. ICT-1 tripped on resultant over loading. There was no fault in the system.

2. Tripping of 315MVA ICT-1 on over load protection (100% loading) was also due to sensitive setting. Same has been changed.

3. Sarnath ICT’s were not N-1 compliant. SPS for Sarnath ICTs needs to be expedited.

PSC Recommendations- 1. Availability of DR/EL needs to be ensured by UP. (Action: UP; Time Frame: 1 month) 2. Tripping on over load protection of ICT’s needs to be disabled. (Action: UPPTCL; Time

Frame: 7 days) 3. Availability of Software for extraction of DR/EL to be ensured. (Action: UPPTCL; Time

Frame: 1 month) 4. Digital data of Sarnath ICT needs to be ensured. (Action: UP; Time Frame: 7 days)

Similar kind of incident was also observed on 7th, 8th & 28th Sep 2014. ICT-1 & 3 at 400/220kV Sarnath station tripped on over load protection. 7 events of multiple elements tripping occurred at 400kV Sarnath station occurred in year-2014 (till 30th Sep 2014). List of the tripping is given below:

S. No. Date

Time

Station Tripped Elements

Generation Loss (in MW)

Load Loss (in MW)

Category

1

30‐Mar‐14

12:35 hrs

400kV Sarnath(UP)

400kV Sarnath(UP)‐Sasaram(PG) 400kV Sarnath(UP)‐Azamgarh 400kV Sarnath(UP)‐Allahabad(PG) 400kV Sarnath(UP)‐Anpara D/C 400kV Azamgarh‐Gorakhpur

Nil Nil GI‐2

2

14‐Apr‐14

09:02hrs

400kV Sarnath(UP)

400 kV Sarnath‐Anpara (L‐5) 400kV Anpara‐Mau (L‐6) 400kVSarnath‐Anpara(L‐3) 400kV Sarnath‐Allahbad(PG) 400kV Sarnath‐Sasram 400kV Sarnath‐Azamgarh 220kV Sarnath‐ Ghazipur 220kV Sarnath‐Gajokhar 220kV Sarnath‐Sahupuri

Nil 422 GD‐1

3 05‐May‐14

09:03hrs

400kV Sarnath(UP)

315 MVA 400/220kV ICT‐1 315 MVA 400/220kV ICT‐2

Nil 179MW

GD‐1

4 30‐Aug‐14

09:43hrs

400kV Sarnath(UP)


Nil 228 GD‐1

5 07‐Sep‐14

17:35hrs

400kV Sarnath(UP)


Nil 457 GD‐1

6 08‐Sep‐14

11:25hrs

400kV Sarnath(UP)


Nil 423 GD‐1

7 28‐Sep‐14

00:18hrs

400kV Sarnath(UP)


Nil 500 GD‐1

PSC expressed concern on large number of tripping at 400/220kV Sarnath station and also requested UPPTCL to implement the recommendations of each event at the earliest possible.

PSC-28/T/7Multiple Element tripping at 220kV Dhauliganga station on 11th Sep 2014 at 08:46hrs




DR/ EL

NHPC Received After 24hrs

POWERGRID Not Received

UP Not Received

Preliminary Report NHPC Received After 24hrs

Detailed Report NHPC Received After 24hrs






IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3;

NHPC, POWERGRID, UP

CEA Grid Standard 15.3; NHPC, POWERGRID, UP


1. Dhuliganga station have connected with rest of the grid via two number of 220kV (400kV charged at 220kV) lines. One from Bareilly (CB ganj) and other from Pithoragarh. Dhauliganga station have four number of 70MW units.

2. On 11th Sep 2014 at 08:46hrs, unit-3 at Dhauliganga station was going to synchronize. At the same time Bus Bar Protection auxiliary MCB tripped due to DC earth fault. Tripping elements & Restoration time of the elements given below:

S.No. Name of feeder/Unit/System

Date & Time Of Break Down

Date & Time Of Restoration

Total outage Hr:min

Causes of Breakdown

1 Unit # 2 11/09/14 08:46:00

11/09/14 09:40:00

00:54 During Synchronization of Unit #3 ,Busbar Protection auxiliary MCB tripped due to DC earth fault

2 Unit # 3 11/09/14 01:30:00

11/09/14 17:43:00

16:13 Unit Fault

3 Unit # 4 11/09/14 08:46:00

11/09/14 09:30:00


4 Line # 1 (Pithoragarh ckt)

11/09/14 08:46:00

11/09/14 09:20:00


5 Line # 2 (CB ganj ckt)

10/09/14 21:18:00

11/09/14 07:20:00

10:02 Distance protection Zone1 operated (Earth Fault at Distance 5.551Km)

6 11/09/14 08:46:00

11/09/14 09:40:00


3. As per PMU data there was no fault in the system. 4. Probable SoE (Sequence of Events) of the event is given below:

5. SoE data didn’t time synchronize. 6. All the elements connected at 220kV Dhauliganga station tripped.

Representative from NHPC informed the details of the tripping as below:

1. In antecedent condition only one Bus at Dhauliganga station was in service and SCADA & Protective relays at Dhauliganga station was not time synchronized.

2. Start command given from CR ,machine goes to SNLU and upto SNLE step but couldn't get synchronized even though the breaker gets close command from synchronizing panel.

3. Unit-3 Circuit breaker puts into Maintenance mode from GIS LCC panel and close operation of breaker was checked and it was found that command is present in trip circuit -2 of CB.

4. Trip circuit - 2 of CB was checked and found the presence of DC earth fault in circuit. 5. In order to trace the DC earth fault ,all the conditions( Main 1 protection relay 87G1 ,Main

2 protection relay 87G2,Overall differential protection relay 870A,Cable differential protection relay 87C ,Bus bar protection relay and CMR tripping relay) which activates the trip circuit -2 were checked and found that an earth fault is present from CMR tripping relay side which was giving a negative to ground voltage (quite enough to operate the trip circuit -2). Remaining relays also checked and found OK. Faulty section was removed.

6. Close-Open Command from GIS LCC panel was given and CB operated normally. 7. CB puts into Normal Mode from GIS LCC panel 8. Unit-3 Synchronized at 17:43 hrs. 9. GPS synchronization of protective relay & SCADA has been completed in November.

PSC Conclusions:

1. Unit-3 at 220kV Dhauliganga station was in the process of getting synchronized. At the same time Bus Bar Protection auxiliary MCB tripped due to DC earth fault. It resulted into operation of Bus Bar Protection for one Bus. As all the elements were connected on one bus only, it resulted into tripping of all the elements.

2. Due to non-synchronization of SCADA & protective relay, timing of the elements tripping couldn’t get accurately. GPS synchronization of protective relay & SCADA has been completed in November.

3. In current situation both buses are in healthy condition & bus coupler is also in healthy condition.

4. Remedial action report was still from NHPC. Same needs to be submitted within 7 days.

PSC Recommendations

1. There is a need to rectify the DC earth fault existing in the System(Action: NHPC; Time Frame: 01 month) 2. All the elements in the switchyard/sub-station should not be on the same bus

PSC-28/T/8:Multiple Element tripping at 400kV Parichha station on 15th Sep 2014 at 11:26hrs Event category: GD-1 Generation loss: 485MW Loss of load: Nil Data Summary received to NRLDC:



DR/ EL UP Not Received Flag Details only




Fault Clearance Time No Fault observed As per PMU data




IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; UP

CEA Grid Standard 15.3; 43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines; CEA Grid Standard 15.4

UP


1. 400/220kV Parichha TPS station have 2*210MW+2*210MW (at 220kV level) & 2*250MW (at 400kV level). Paricha TPS was connected with rest of the grid via two 400kV lines Mainpuri-Paricha. Three 220kV lines to Orai, one to Bhartna, one to Jhusi & one to Dorana.

2. In antecedent condition 400kV Parichha-Mainpuri-I & II lines were under shutdown due to tower collapsed in the line.

3. It has been reported by Parichha TPS site that 400kV side, Y-pole of circuit breaker of 315MVA ICT-II bursted. It resulted in tripping of ICT-II on standby earth fault protection.

4. 315 MVA ICT-I also tripped on over current protection. 5. As 400kV Parichha-Mainpuri D/C was already under S/D (shut down) & Both the ICTs

also tripped during fault. Further evacuation system for units was not available; it resulted into tripping of Parichha generating units no V & VI.

6. Units no V & VI tripped on over frequency. 7. As per PMU data no fault observed in the system.

8. Report & flag details has been received from UP. It was mentioned in the report that “Printouts of disturbance recorder/event logger are not available”

No representative from UPRVUNL attended the meeting.

PSC Conclusions: 1. It has been reported by Parichha TPS site that 400kV side, Y-pole of circuit breaker of

315MVA ICT-II had burst. It resulted in tripping of ICT-II on standby earth fault protection. 315 MVA ICT-I also tripped on over current protection. Units no V & VI tripped on over frequency due to evacuation problem.

2. Over frequency setting of Units no V & VI needs to be checked. 3. Over current setting of ICT’s needs to be checked. 4. Availability of digital data needs to be looked into. 5. RPC requested all the utility to attend the meeting so that event could be discussed in

details. 6. Operational issue of non-availability of 400kV Parichha-Mainpuri lines from 31st May

2014 needs to be looked into. PSC Recommendations:

1. 400kV Parichha-Mainpuri D/C line needs to be available at the earliest possible. (Action: UPPTCL, time frame: 1 month)

2. Over current setting of ICT’s needs to be checked and corrected, if so required. (Action: UPRVUNL; Time Frame: 15 days)

3. Non-survival of units on house load needs to be investigated and corrective action be taken. (Action: UPRVUNL; Time Frame: 15 days).

4. Over frequency setting of Units no V & VI needs to be checked and corrected, if so required.. (Action: UPRVUNL; Time Frame: 15 days).

5. Availability of digital data needs to be ensured. (Action: UPRVUNL; Time Frame: 7 days).

6. Detailed Report from UP to be submitted. (Action: UPRVUNL; Time Frame: 7 days). PSC-28/T/9Multiple Element tripping at Unnao station on 16th Sep 2014 at 05:03hrs

Event category: GD-1 Generation loss: Nil Loss of load: 680MW Data Summary received to NRLDC:


Availability of Digital Data (SCADA Data)

Available (Partially)

ICT tripping didn’t capture in SoE

DR/ EL UP Received (Partially)

After 24hrs (DR didn’t receive for 400kV Agra‐Unnao line)





Phase of the Fault Red phase As per PMU data



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; UP




UP


1. 765/400kV Unnao station have 765kV Anpara-C to Unnao line, 765/400kV 1000MVA two ICT’s, 400kV Unnao-Bareilly D/C line, 400kV Agra-Unnao S/C, 400kV Unnao-Panki S/C, 400kV Unnao-Lucknow(PG) D/C, Unnao-Lucknow(UP) S/C & 400/220kV 315MVA two ICT’s.

2. R-phase to earth fault took place on 400kV Unnao-Panki line. At Panki S/S circuit breaker tripped but at Unnao S/S, circuit breaker auto reclosed (with time taken upto 150 msec. due to non-receipt of carrier signal).

3. Due to this, at Unnao S/S, 1000 MVA ICT-I & II tripped from 400kV side on overcurrent & earth fault protection. Delayed tripping of Panki line caused operation of 2nd stage E/F relay (In>2) configured in CB overcurrent and earth fault relays (50/51N) provided on 400kV side of 1000 MVA ICTs. This resulted tripping of both 765/400kV ICTs from 400kV side

4. 400kV Unnao-Agra line tripped from Agra end in zone-1. 5. All 3-phase of the Agra end of 400kV Agra-Unnao line & Panki end of 400kV Panki-

Unnao line finally tripped due to PD (Pole Discrepency) operation in Y&B phase of the line.

6. Connectivity Diagram is given below:

7. Flag Details is mentioned below:

8. Fault record obtained from Siprotec relay shows that R ph earth fault occurred on 400 kV

Unnao line at a distance of 1.6 km from Unnao. Because of presence of series compensation on 400kV Unnao-Bareilly lines, both Main I and Main II relays on Panki line are configured to trip in 1st zone only on receipt of permissive carrier commands from other end. However, carrier counter readings show that permissive commands were issued by both relays of Unnao and Panki ends but no command was received at Unnao end and only one command received at Panki end (probably due to high fault level on R Ph which is one of the phase of phase to phase carrier coupling). This resulted delayed tripping by main II relay (Siprotec) as the fault was cleared by Z1 element instead of Z1B. Main I relay (Micom) only provided start indication (it is configured in permissive Z1 mode) due to failure of carrier command

9. Fault clearance time was 200ms. Max dip in Red phase 10. As per NR SoE, 400kV Agra-Unnao line tripped from Agra end immediately after

occurrence of fault in 400kV Unnao-Panki line

PSC Conclusions:

1. R-phase to earth fault took place on 400kV Unnao-Panki line. At Panki S/S circuit breaker tripped but at Unnao S/S, circuit breaker auto reclosed (with time taken upto 150 msec. due to non-receipt of carrier signal).

2. Delayed clearance of fault in 400kV Unnao-Panki line was due to non-receipt of carrier command from Panki end. However link was checked by UPPTCL on next day and no problem was found.

3. 400kV Agra-Unnao line tripped from Agra end due to overreaching of distance element. 4. 765/400kV ICTs at Unnao station tripped on Over current stage-2 protection. Setting is

900mA with 100ms time delay. Over current setting was very sensitive. 5. Carrier inter-tripping scheme in 400kV Unnao-Panki line to be looked into. 6. At 400 KV S/S Panki and Agra, the reason of CB pole discrepancy should be checked

and remedial action be taken.

PSC Recommendations: 1. Complete Protection review is required at 765/400kV Unnao stations. (Action: UPPTCL;

Time Frame: 30 days) 2. Stage-2 setting of earth fault/over current protection of 1000MVA ICT’s at Unnao station

to be corrected. (Action: UPPTCL; Time Frame: 15 days) 3. Carrier inter-tripping scheme in 400kV Unnao-Panki line to be checked. (Action:

UPPTCL; Time Frame: 15 days) 4. Distance protection setting of 400kV Agra-Unnao line to be checked & corrected. (Action:

UPPTCL; Time Frame: 15 days)

5. At 400 KV S/S Panki and Agra, the reason of CB pole discrepancy should be checked and remedial action be taken. (Action: UPPTCL; Time Frame: 15days)

6. Availability of software for extraction of DR/EL to be ensured. (Action: UPPTCL; Time Frame: 1 month)

PSC-28/T/10:Multiple Element tripping at 400kV Daultabad station on 19th Sep 2014 at 12:29hrs



Availability of Digital Data (SCADA Data) Available (Partially)

DR/ EL Haryana Not Received

POWERGRID Received After 24hrs

Preliminary Report Haryana Received After 24hrs


Detailed Report Haryana Received After 24hrs




Phase of the Fault Max dip Red phase As per PMU data



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; Haryana

IEGC 5.2.r; CEA Grid Standard 15.3

POWERGRID



Haryana


1. During replacement of CT of Jharli ckt-1 at Daultabad station. Crane came into induction zone of the bay, it converted into bus fault for Bus-1 at Daultabad station. Connectivity Diagram is given below:

2. Detailed report received from POWERGRID is given below:

3. Flag details of tripping is given below:

4. Detailed report received from Haryana is given below:

5. Action to be taken (As per Haryana Report):

PSC Conclusions: 1. The exact location of fault need to be relooked. (Fault b/w CB & CT of line side or Bus

side). 2. Daultabad-Gurgaon ckt-2 tripped from Gurgaon end in zone-2 instead of DT receipt (as

per Haryana report). Daultabad-Gurgaon Ckt-1 tripped on DT receipt and successfully auto reclosed.

3. The persistence of fault for 400 ms to be investigated. (Which element(s) kept feeding the fault for such a long duration?)

4. Whether Bus Bar Protection was operated? 5. The tripping of Tie CB (414) of ICT-3 & Sec-72 ckt-2 at Daulatabad end on DT received

from remote end to be looked into. 6. Sending of carrier signal from Gurgaon end needs to be looked into. 7. Availability of DR/EL needs to be ensured by Haryana.


1. Haryana should investigate the issues like non-operation of Bus Bar Protection, Sending of carrier signal from Gurgaon end and submit point wise reply to all the points raised by PSC. (Action: Haryana; Time Frame: 15 days)

2. The Bus Bar Scheme at Daulatabad to be reviewed with following recommendations: a. Practice of sending DT at remote end may be discontinued (in case of line

charged via both main & tie CB) as for 1½ Breaker Scheme all the feeders are to be remained charged through the Tie CBs.

b. The tripping of Tie CBs may not be included in case of Bus Bar protection operation as it may not render the tripped Bus feeders charged.

c. When tie CB is under off condition then DT would be sent to remote end of that breaker.

(Action: HVPNL; Time Frame: 15 days)

PSC-28/T/11:Multiple Element tripping at 400kV Rampur HEP station on 20th Sep 2014 at 14:15hrs

Event category: GD-1 Generation loss: 180MW Loss of load: Nil Data Summary received to NRLDC:



Available Time Synchronization Problem

DR/ EL SJVNL Not Received

Preliminary Report SJVNL Not Received

Detailed Report SJVNL Not Received



Phase of the Fault Red phase As per PMU data



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; SJVNL



SJVNL


1. At 14:15hrs, 400kV Jhakri-Rampur ckt-1 tripped on R-phase to earth fault. At the same time running unit -1, 4 & 5 of Rampur HEP also tripped. Reason of tripping yet to be confirmed by SJVNL.

2. As per PMU data it seems line auto reclosed after 1000ms & due to persistent fault line finally tripped. Fault clearing time was ~100ms & max dip was in Red-phase.

3. Slight oscillations in Karcham frequency also observed through PMU data.

PSC Recommendations: 1. Reasons for tripping of running generation units at Rampur HEP needs to be investigated

and reportd. (Action: SJVN Ltd; Time Frame: days) 2. Time synchronization of the digital data to be ensured (Action: SJVN Ltd; Time Frame: 15

days) 3. Oscillations in Karcham HEP frequency to be investigated (Action: JVL, Time frame: 1

month) 4. Preliminary report, DR/EL & detailed report was awaited from SJVN Ltd. The report

should be submitted on priority. (Action: SJVN Ltd; Time Frame: 7 days)

PSC-28/T/12:Multiple Element tripping at Dadri Station on 23rd Sep 2014 at 08:46hrs Event category: GD-1 Generation loss: 165 MW Loss of load: Nil Data Summary received to NRLDC:



Available Time synchronization problem

DR/ EL NTPC Not Received


Preliminary Report NTPC Not Received


Detailed Report NTPC Received After 24hrs



Fault Clearance Time 200ms As per PMU & DR data

Phase of the Fault R‐Y phase to phase fault As per PMU & DR data



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; NTPC, POWERGRID


POWERGRID



NTPC


1. On 23-Sep-14 at 08:46 Hrs, 400kV Dadri-Mandola Ckt-II tripped on R-Y phase to phase fault.

2. The setting at Mandola for Distance protection is: a. REL 670 Relay: Zone-1 will be tripped only in case of carrier receipt b. MiCOM Relay: Zone-1 is time delayed by 100msec and time will be bypass in

case of carrier receipt. 3. As carrier was not received from Dadri end, the fault was isolated from Mandola end after

time elapsing of 100msec.It was confirmed from NTPC Dadri end that carrier was sent from Dadri end but was not received at Mandola end. Please note that wave traps are installed in “R” & “Y” phase and fault was taken placed in “R” & “Y” phase therefore tripping signal might lost.

4. Maximum Dip observed in R & Y phase (~115kV). 5. Fault clearing time ~200ms. 6. Tripping of line from both ends seems to be delayed by ~100ms. 7. As per NR SoE, ST-1 tripped at 08:46:43.962hrs i.e. around 350ms after the clearance of

fault. 8. As per NTPC report, Dadri Mandola ckt-2 tripped on phase to phase fault which led to trip

Gas Station unit#1 tripped on "IMPEDANCE PROTECTION SHORT TIME ". Dadri-Mandola line is connected with " FACT "( Flexible AC transmission compensation) which provides 100msec time delay for Zone-1 distance protection. Short time Impedance protection setting for unit-1 is also 100 msec. Therefore Dadri Gas station Unit#1 tripped & Steam turbine tripped because of only running unit#1 tripped

9. There is no FACTS compensation in Dadri-Mandola or any line emanating from Mandola. This may kindly be looked into.

10. If 100 ms time delay is required, then delay for generator may please be accordingly coordinated or else every time during phase to phase or 3 ph fault near Dadri, units could trip

POWERGRID representative briefed the house about the event:

1. Initially when FSC came into picture in Panki-Muradnagar line & at Ballabgarh station, it was decided that all the outgoing lines from Dadri station would have time delay of 100ms in case of non-receipt of carrier from remote end.

NTPC representative briefed the house about the event: 1. Dadri Mandola ckt-2 tripped on phase to phase fault. 2. Reason of tripping of GT on backup impedance protection couldn’t be finalized. 3. "IMPEDANCE PROTECTION SHORT TIME" setting has been revised from existing

100ms to 600ms.

PSC Conclusions: 1. R-Y phase to phase fault occurred in 400kV Dadri-Mandola line. Line have POR scheme

due to availability of FSC in 400kV Panki-Muradnagar line(390kM) with 40% compensation.

2. GT (Gas Turbine) at Dadri station tripped on “backup impedance protection short time”. ST (Steam Turbine) tripped due to tripping of GT.

3. "IMPEDANCE PROTECTION SHORT TIME" setting has been revised from existing 100ms to 600ms.

4. Digital Data reporting to be looked into. PSC Recommendations:

1. Time delay at Mandola and Dadrri end to be same(100 msec.) because of FSC compensation in 400kV Panki-Muradnagar line. (Action: POWERGRID, NTPC; Time Frame: 7 days)

2. Reason of tripping of ST within 350ms of tripping of GT needs to be investigated and corrective action be taken. (Action: NTPC; Time Frame: 15days)

PSC-28/T/13: Multiple Elements tripping at 400kV Chamera-II HEP station on 24th Sep 2014 at 20:41hrs

Event category: GD-1 Generation loss: 280MW Loss of load: Nil Data Summary received to NRLDC:


Availability of Digital Data (SCADA Data) Available Time synchronization problem

DR/ EL NHPC Received After 24hrs


Detailed Report NHPC Received After 24hrs


Violation of Clauses IEGC 5.2.r & CEA Grid Standard 15.3 NHPC


1. Chamera-1 HEP is connected with single ckt Chamera-II, Chamba(Pooling) & Kishenpur station. Chamera-I HEP have three units of 100MW.

2. BFV PLC fault occurred due to failure of UPS causing closure of BFV & further reverse power protection started and unit tripped by emergency push button.

3. On inspection it was found that fuse of battery bank of UPS was burnt out due to which UPS failed.

4. The fuse of UPS replaced after checking the healthiness of UPS and BFV was opened.

5. After normalizing the preconditions of unit, it was started and synchronized with the grid. 6. As per PMU data no fault observed in the system. 7. Details received from NHPC is given below:

PSC Conclusions: 1. BFV PLC fault occurred due to failure of UPS causing closure of BFV & further reverse

power protection started and unit was tripped by emergency push button. 2. Fuse of battery bank of UPS had burnt due to which UPS failed. 3. Reason of fault, location of fault & nature of fault to be investigated by NHPC in detail. 4. Time synchronization of digital data has been completed by 12th Dec 2014. 5. Earlier there was shortcoming in protection also. In case of tripping of BFV machine

should also be tripped but same had not occurred in this tripping. It has been rectified. Now in case of tripping of BFV valve automatic tripping command would be sent to machine also.

PSC Recommendations: 1. Procurement of new redundant UPS system. It is reported to be in the process. (Action:

NHPC, Time Frame : 3 months) 2. NHPC to furnish the complete details of tripping covering Reason of fault, location of

fault & nature of fault and findings. (Action: NHPC; Time Frame: 7 days)

PSC-28/T/14:Multiple Element tripping at 220kV Nuna majra station on 24th Sep 2014 at 20:26hrs Event category: GD-1 Generation loss: Nil Loss of load: 150MW Data Summary received to NRLDC:



DR/ EL Haryana Not Received

Preliminary Report Haryana Not Received

Detailed Report Haryana Not Received



Phase of the Fault Max dip Red phase As per PMU data



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; Haryana




Haryana


1. On 24th September 2014 at 20:26hrs, 220kV Nunamajra-Rohtak D/C, 220kV Bahadurgarh(PG)-Nunamajra(HVPNL) D/C, 220kV Daultabad(HVPNL)-Nunamajra(HVPNL) D/C tripped due to R-phase to earth fault at Bus of 220kV Nunamajra S/s.

2. It is inferred from PMU data max dip was in R phase and got cleared in 480ms. 3. Delayed clearance of fault has observed through PMU data. 4. Digital data of Nuna majra station is not available at NR SoE

Representative from Haryana informed the details of the tripping as below:

1. Red-phase jumper snapped from Bus Isolator resulted into Bus Fault for 220kV Bus-1 at Nuna majra end.

2. Bus Bar scheme at 220kV Nuna majra station is not installed. 3. Due to absence of bus bar protection all the 220kV lines tripped from remote end. It

resulted into delayed clearance of fault. 4. All the relays at Nuna majra station is either static or electro mechanical relay.

SE, NRPC stated that many of the decisions taken by NRPC were still pending at utility end. For example it was earlier discussed in 25th PSC meeting that in case of unavailability of Bus Bar Protection, utility would change the zone-3R setting to 160ms & trip the bus coupler within 100ms on over current/earthfault protection. Extract of the 25th PSC MoM is given below:

He requested that utilities should consider implementation of the above decision.

PSC Conclusions: 1. There was a Bus fault at 220kV Nuna majra station. Due to unavailability of bus bar

protection at 220kV Nuna majra station, all the lines tripped from remote end in zone-2 timing. It resulted into delayed clearance of fault.

2. Sequence of event coudn’t be finalised due to unavailability of EL or numerical relays. 3. In case of unavailability of Bus Bar scheme at Nuna majra, scheme suggested by RVPNL

(as discussed in previous event) should be opted by station so that elements connected to other bus wouldn’t trip.

4. Preliminary Report, Detailed report and DR/EL from Haryana yet to be received. 5. There is continuous violation the IEGC clause 5.2.r & CEA Grid Standard 5.3 as Detailed

report, DR/EL were not being received from HVPNL in past also. 6. Every station should have submitted the DR/EL, Preliminary report to RPC/RLDC within

24hrs. Sub-station/power station incharge should be advised to furnish the details of tripping to RPC/RLDC within 24hrs.


7. In case of unavailability of Bus Bar scheme at Nuna majra, scheme suggested by RVPNL and agreed in the 25th PSC meeting should be opted by station so that elements connected to other bus wouldn’t trip. (Action: HVPNL; Time Frame: 7 days)

8. Haryana should submit the detailed report of the event. (Time Frame: 7days) 9. Bus Bar Protection to be installed at 220kV Nuna majra station. (Action: HVPNL; Time

Frame: 3 months) 10. Numerical relay to be installed at 220kV Nuna majra station. (Action: HVPNL; Time

Frame: 3 months)

Representative from NRLDC stated that one common google group ([email protected]) has also been formulated since last one year to share the information related to tripping. Till now no utility is using that facility to share the information.

PSC-28/T/15:Multiple element tripping at 220kV Obra TPS on 24th Sep 2014 at 12:50hrs Event category: GD-1 Generation loss: 483 MW Loss of load: Nil Data Summary received to NRLDC:



DR/ EL UP Not Received Only flag details





Phase of the Fault Max dip Blue phase As per PMU data



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; UP




UP


1. In antecedent condition, following were the elements under shut down: At Obra TPS, generating units nos. 9 & 11 220 kV Obra-Sahupuri Ckt-I & II 220 kV Obra-Rewa Road (Allahabad) Ckt-II At Obra TPS, 220/132 KV, 100 MVA ICT-III (Pipri)

2. It has been reported by UPRVUNL site that analysing the flags/protection appeared/operated at different 220kV elements at ATPS, Obra end and 132kV Obra Hydel Switchyard, it appears that earth fault occurred at 132kV system and it was sensed by Obra Hydel units. It was cleared by 220kV Breaker of ICT-Ist & ICT-IInd at Obra ATPS. As these breakers are very old and sluggish, this fault was also sensed by other connected elements of 220kV Bus like Generator Unit No.1 & Generator Unit No.2, 240 MVA (220/400 KV) ICT-Ist & IInd, BTPS, It was also sensed and cleared by 220kV Obra-Allahabad circuit-III at Allahabad end in Zone-III. Thus the fault was cleared by the connected elements of 220kV Bus, isolating the Bus of ATPS, Obra. Name of the tripping elements is tabulated below:

3. Connectivity diagrams given below:

4. Flag details is given below:

5. Digital data of 220kV Obra TPS is not available at NR SoE


1. SLDC should constitutes an internal committee for analyzing the tripping at Obra TPS and submit the detailed report within 1month to RPC/RLDC, covering following aspects:

Delayed Clearance of fault needs to be investigated. Exact sequence of event yet to

be ascertained due to non-availability of DR/EL from the stations. Availability of DR/EL should be ensured.

Tripping of Obra (hydel) unit-1 on differential protection operation needs to be investigated and corrective action be taken.

Non tripping of 220kV Onra-Allahabad ckt3 from obra end needs to be investigated and corrective action be taken.

At Obra TPS, the tripping/opening time of all the 220kV circuit breakers be checked and set right.

At Obra TPS, the protection setting of all the 220kV side elements be checked and set right.

Protection coordination of different elements at Obra TPS needs to be reviewed. 132kV level fault getting cleared from 400kV stations is cause for concern and need

to be investigated. (Action: UPRVUNL, Time frame: 01 month)

2. Healthiness of bus bar protection/ Local breaker backup needs to be ensured.

(Action:UPRVUNL, Time frame: 03 months) 3. At Obra TPS, over hauling/replacement of sluggish circuit breakers to be done.

(Action:UPRVUNL, Time frame: 01 months) 4. At Obra TPS, all the defective distance protection relays and transformer relays be

replaced. (Action:UPRVUNL, Time frame: 02 months) 5. Availability of digital data needs to be ensured(Action: UPRVUNL, Time frame: 01

months)

Similar kind of incident also occurred on 30th Sep 2014 at 10:15hrs. Members may like to discuss the tripping in addition to the above stated points.

Remedial Action to be Taken (As per UP Report) :-

1. At Obra TPS, the tripping/opening time of all the 220 KV circuit breakers be checked and set right. (Action UPRVUNL)

2. At Obra TPS, the protection setting of all the 220 KV side elements be checked and set right. (Action UPRVUNL)

3. AT Obra TPS, over hauling/replacement of sluggish circuit breakers be done. (Action UPRVUNL)

4. AT Obra TPS, all the defective distance protection relays and transformer relays be replaced. (Action UPRVUNL)

Detailed report & Flag details has been received from UP. It was mentioned in the report that

“Printouts of disturbance recorder/event logger are not available”. No representative from UPRVUNL attended the meeting.

PSC-28/T/16:Collapse of Kashmir Valley on 7th Oct 2014 at 21:31hrs

Data Summary received to NRLDC:


Availability of Digital Data (SCADA Data) Partial Available

DR/ EL

Wagoora (NR‐2) Received Received after 24hrs

Uri‐I (NHPC) Received Received after 24hrs

Uri‐II (NHPC) Received Received after 24hrs

Dulhasti (NHPC) Received Received after 24hrs

J&K Not received

Preliminary Report

Wagoora (NR‐2) Received Received after 24hrs

NHPC Received Received after 24hrs

J&K Not received

Detailed Report

J&K Not Received

POWERGRID‐ NR2 Received

NHPC Received


Violation of Clauses IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3

J&K, NHPC, POWERGRID-NR2

IEGC 4.6.3; 43.4.D of CEA Technical

Standard for Construction of Electrical Plants and Electric

Lines; CEA Grid Standard 15.4

J&K

43.4.E of CEA Technical Standard for Construction of Electrical Plants and Electric

Lines

J&K, NHPC, POWERGRID-NR2


1. On 7th Oct 2014, windstorm has occurred in J&K. In the meantime many lines & generating unit in that area tripped. After tripping of 220kV Mirbazar-Pampore D/C island created & island of valley collapsed due to load generation imbalance. Following are the list of tripped elements:

• 400kV Kishenpur-Dulhasti D/C • 400kV Kishenpur-Baglihar ckt • 400kV Kishenpur-New Wanpoh D/C • All running unit of 400kV Uri-II HEP (4*60MW) • All running unit of 400kV Uri-I HEP • 220kV Wagoora-Zainakote ckt 1 • 220kV Wagoora-Budgam-Zainakote ckt2 • 220kV Wagoora-Pampore D/C • 220kV Pampore-Mirbazar D/C • Running unit at Pampore GT

2. Probable SoE (Sequence of Events) of the event is given below:

Name of Line/ICT Outage Date/Time Details of tripping Remarks

400KV Kishenpur‐Wanpoh Line‐2

21:43:43.475hrs R‐ Phase to Earth Fault, Z1,F/L= 6.182 KM, F/C=10.65KA, A/R OPTD but it was unsuccessful

As per DR of Kishenpur end & PMU data


21:43:45.515hrs Line finally tripped due to unsuccessfully auto reclosing



21:47:39.820hrs Y‐Phase to Earth Fault, Z1, F/L=8.688 KM, F/C=10.24 KA, A/R OPTD & it was successful



21:47:41.820hrs Y‐Phase to Earth Fault, Z1, F/L=8.688 KM, F/C=10.24 KA, A/R OPTD & it was successful



21:47:49.400hrs

Again Y‐Phase to Earth Fault, Z1, F/C~10KA, & Line finally tripped due to again occurrence of fault in breaker reclaim time(25second)


400KV Kishenpur‐ Baglihar Line‐1

21:46:50.080hrs

R‐ Phase to Earth Fault, Z1, F/L= 12.19 KM, F/C=9.365 KA, A/R not operated & line finally tripped on PD (Pole Discrepency)


400 KV Kishenpur‐Baglihar Line‐2

21:49:34.320hrs Y‐ Phase to Earth Fault, Z1, F/L= 1.925 KM, F/C=11.02 KA, A/R OPTD & it was successful


400 KV Kishenpur‐Baglihar Line‐2

21:49:40.420hrs

Y‐ Phase to Earth Fault, Z1, F/L= 1.925 KM, F/C=11.02 KA, & Line finally tripped due to again occurrence of fault in breaker reclaim time(25second)


400kV Kishenpur‐Dulhasti ckt

21:54:09hrs Blue‐phase fault. Line opened from Kishenpur end only

As per Kishenpur & Dulhasti end DR. PMU data. Earth Wire Snapped (Location No.:338‐339 )

400kV Kishenpur‐Dulhasti ckt

21:54:09.420hrs

3‐phase fault. All 3‐phase opened from Dulhasti end & Remaining R&Y‐phase opened from Kishenpur end.

As per Kishenpur & Dulhasti end DR. PMU data

220kV Pampore‐Mirbazar Double ckt

22:20:55hrs

One of the line of Mirbazar‐Pampore tripped. At the same time slight oscillation observed in PMU data. It may be due to overloading of parallel ckt. Timing of tripping inferred from PMU data.

As per PMU data & telephonic conversation with Mirbazar station

Uri‐I unit‐3 22:20:59.535hrs Unit over speed As per Uri‐I detailed report

Uri‐I unit‐1 22:20:59.648hrs Mechanical over speed As per Uri‐I detailed report

Uri‐I unit‐2 22:21:02.577hrs Over Frequency Protection Tripped

As per Uri‐I detailed report

Uri‐I unit‐4 22:21:02.588hrs Over Frequency Protection Tripped

As per Uri‐I detailed report

Unit‐2,3&4 of Uri‐II HEP 22:21:04.495hrs Under Frequency Protection operated

As per Uri‐II DR details & NR SoE. Unit‐I has already tripped at 21:48hrs due to some internal fault.

Valley Collapsed 22:21hrs

Valley collapsed. It may be due to load generation imbalance in the island. 700MW generation complex of Uri HEP also tripped. Pampore GT also tripped.

Timing of tripping of Pampore GT was not available. It may be tripped at the time of high frequency in the island.

3. Sub-events of Kashmir valley collapse are listed below: a. Tripping of 400kV Kishenpur-Baghlihar ckts & generation loss of Baghlihar units b. Tripping of 400kV Kishenpur-New Wanpoh ckts c. Tripping of Kishenpur-Dulhasti ckt & generation loss of Dulhasti units d. Collapse of Kashmir Valley

a. Tripping details of Kishenpur-Baghlihar ckts: Event Category: GD-1 Generation Loss ~450MW Load Loss: Nil

Over all Analysis based on PMU, DR/EL from station:

As per DR details of Kishenpur end, R-phase to ground fault occurred in 400kV Kishenpur-Baghlihar ckt1 at 21:46:50.080hrs. Single phase of Kishenpur-Baghlihar ckt1 successfully tripped. After 160ms of tripping of R-phase of the line, current in other two phase (Y&B) became very low for 740ms and again revived. It seems 3-phase tripping occurred at Baghlihar end and again 3-phase auto reclosing occurred. After 1000ms of opening of R-phase breaker, breaker of Kishenpur end didn’t auto-reclose. It resulted into tripping of other two phases (Y & B-phase) on PD (Pole Discrepency) after 2.5second.

Y-phase to ground fault occurred in 400kV Kishenpur-Baghlihar ckt2 at 21:49:34.320hrs. Line auto reclosed successfully after 1000ms. Fault again occurred at 21:49:40.420hrs within breaker reclaim time in same phase and all 3-phase of the line tripped.

Baghlihar units tripped before tripping of remaining ckt-2. DR/EL from Baghlihar end not received

PSC Conclusions & Recommendations:

1) Non auto-reclosing of Kishenpur end of 400kV Kishenpur-Baghlihar ckt1 after 1000ms should be checked at the time of line shutdown. (Action: POWERGRID; Time Frame: 1 months)

2) Reason of 3-phase tripping of Baghlihar end of 400kV Kishenpur-Baghlihar ckt1 to be checked 7 corrected. (Action: J&K; Time Frame: 1months)

3) Reason of tripping of units of Baghlihar before tripping of ckt2 needs to be looked into. (Action: J&K; Time Frame: 1months)

b. Tripping details of Kishenpur-New Wanpoh ckts: Event Category: GI-2 Generation Loss ~Nil Load Loss: Nil

Over all Analysis based on PMU, DR/EL from station: As per DR details of Kishenpur end, R-phase to ground fault occurred in 400kV

Kishenpur-New Wanpoh ckt2 at 21:46:43.475hrs. Single-phase tripping occurred from both end. Line auto reclosed unsuccessfully after 1000ms. All 3-phase of the line tripped.

Y-phase to ground fault occurred in 400kV Kishenpur-New Wanpoh ckt 1 at 21:47:39.820hrs. Single-phase tripping occurred from both end. Both main & tie breaker of the line auto reclosed after 1000ms. Fault again occurred in breaker reclaim time in same phase at 21:47:49.400hrs and all 3-phase of the line tripped.

Reason of rise in frequency in case of tripping of needs to be looked into. As per NR SoE it was seen that breaker of New Wanpoh end reclosed in 1000ms

however in DR data reclose time was clearly shown as 2000ms

PSC Conclusions & Recommendations: 4) Discrepancy between DR time gap & NR SoE needs to be checked.(Action:

POWERGRID; Time Frame: 7days)

c. Tripping details of Kishenpur-Dulhasti ckt: Event Category: GD-1 Generation Loss ~370MW Load Loss: Nil

Over all Analysis based on PMU, DR/EL from station: Two incident of fault, First fault was in blue-phase of 400kV Kishnepur-Dulhasti line

at 21:54:09hrs (PMU timing & Kishenpur end DR timing). B-phase tripped in zone-1 timing from Kishenpur end but didn’t clear from dulhasti end as dulhasti end was not captured it in any zone.

B-phase fault was feeding through Dulhasti end till 400ms

After 420ms of first incident, 3-phase fault occurred in the line. All 3-phase of dulhasti end tripped in zone-1 & remaining two phase of Kishenpur end also tripped.

PSC Conclusions: Kishenpur end send the carrier signal but due to problem in PLCC signal

couldn’t receive at Dulhasti end. End to end testing also done on 15th Dec 2014.

Carrier was not received at Dulhasti end and line finally tripped from Dulhasti end in zone-2 timing.

Dulhasti end GPS is now time synchronized. New GPS to be commissioned within 4 months.

Y-phase open signal was wrongly initiated in DR of Kishenpur end of 400kV Kishenpur-Dulhasti line. This problem was due to digital signal wiring and has been rectified by POWERGRID.

PSC Recommendations

5) Speech signal of 400kV Kishenpur-Dulhasti ckt to be rectified. (Action: POWERGRID; Time Frame: 1month)

d. Collapse of Kashmir Valley: Event Category: GD-1 Generation Loss ~750MW Load Loss: 450MW

Over all Analysis based on PMU, DR/EL & telephonic conversation from station: After tripping of both the ckt of 400kV Kishenpur-New Wanpoh. Valley is connected

with rest of the grid by two lines. 220kV Kishenpur-Mirbazar & Kishenpur-Ramban-Mirbazar. Further Mirbazar connected with Pampore by D/C.

It seems that at 22:20:55hrs one ckt of 220kV Pampore-Mirbazar tripped. As per PMU data slight oscillations observed in the frequency & voltage plot. It may be due to overloading of other ckt. As per SCADA data other ckt of Pampore-Mirbazar also tripped.

In antecedent condition valley was exporting 280MW power to rest of the grid. After tripping of Pampore-Mirbazar D/C valley became surplus in generation & it resulted into tripping of m/c at Uri-I on mechanical overspeed, over frequency protection etc.

Frequency of Wagoora shot up because of generation load mismatch in the valley. Machine at Uri-II tripped on under frequency.

PSC Conclusions & Recommendations:

6.) Tripping of all the units at Uri-I & Uri-II HEP could be prevented in case of staggering in the over frequency setting in generators at Uri-I & Uri-II HEP. NHPC may look into the matter & take corrective measures. (Action: NHPC; Time Frame: 1 month)

7.) Reason of tripping of machine at Uri-II on under frequency is still not clear. It couldn’t be concluded because of fire incident in Uri-II HEP. NHPC may furnish the complete details of tripping of machine at Uri-II HEP. (Action: NHPC; Time Frame: 1 month)

8.) PDD< J&K to expedite & intimate the current status of the System Protection Scheme (SPS) that was planned to be built after the collapse of Kashmir valley on 06-07 Jan-2012 as per the report issued by CEA (Action: J&K; Time Frame: 6 month)

PSC-28/T/17Multiple Element tripping at 400kV Harsh Vihar on 8th Oct 2014 at 07:53hrs & 14th Sep 2014 at 17:50hrs

Event category: GD-1 Generation loss: Nil Loss of load: 100 MW Data Summary received to NRLDC:



Partial Available Available only for NTPC end

DR/ EL NTPC Received Received after 24hrs

DTL Received Received after 24hrs

Preliminary Report NTPC Received Received after 24hrs

DTL Received Received after 24hrs

Detailed Report

NTPC Received Submitted in PSC

DTL Partially Received Remedial action report not received


Fault Clearance Time 1250ms As per PMU data & DR details

Phase of the Fault Red‐Phase As per PMU data & DR details



IEGC 5.2.r; CEA Grid Standard 15.3; CEA Grid Standard 3.1.e

DTL

IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; CEA Grid Standard 3.1.e

NTPC


1. On 8th Oct 2014 at 07:53hrs, Red-phase to ground fault occurred in 400kV Dadri-Harsh Vihar ckt2. Red phase breaker of the line tripped from Dadri end but Harsh Vihar end relay didn’t trip.

2. 400kV Dadri-Harsh Vihar ckt-1 tripped from Dadri end immediately after fault & Harsh Vihar end relay also tripped due to DT received from remote end. 400kV Dadri-Harsh Vihar ckt-1 may be tripped due to overreaching of distance protection. Fault was continuously feeding through other two phase(Y&B-phase) of ckt-2 as R-phase of the line didn’t trip from Harsh Vihar end.

3. 220/66kV 160MVA ICT-1 tripped on backup earth fault protection. 4. 220/66kV 160MVA ICT-3 tripped on backup over current, e/f protection. 5. 400kV Bus Coupler also tripped on backup over current & earth fault protection. 6. 210MW unit-4 also tripped. But as per NR SoE unit tripped before the fault occurrence

time. 7. Probable SoE (Sequence of Events) of the event is given below:

Similar kind of tripping also occurred on 14th Sep 2014 at 17:50hrs. Fault clearance time was ~1350ms.

Representative from DTL informed the details as below-

1. 400kV Dadri-Harsh Vihar ckt-1 was healthy, DT should not be sent from Dadri end. This is mal-operation of relay at Dadri.

2. Harsh Vihar end of 400kV Dadri-Harsh Vihar ckt-2 didn’t sense the fault in any zone. The fault current/Voltage recorded is 1298A/51.23kV which indicates very high impedance about 39ohms. Exact reason couldn’t be finalized. The CT shorting links may be the probable reason.

3. The relays of Harsh Vihar end of both 400kV Dadri-Harsh Vihar lines has tested & found satisfactory as advised by NTPC Dadri. The CT shorting links were connected properly after testing. After that one incident of fault in 400kV Dadri-Harsh Vihar ckt2 also took place & relays of this line operating properly during line fault.

4. The ICT-1 & 3 tripped on backup earth fault protection due to zero sequence current which was fed to the fault from transformers due to presence of tertiary winding.

5. There is no back feeding/ interconnections at Harsh Vihar station. 6. The zero sequence current was absent due to delta connected load (66/11kV Pr. Tr.) at

66kV side I/C shall not trip under this condition. 7. Time synchronization of DR to be attended at DTL end.

Representative from NTPC informed the details of the tripping as below- 1. M/s ABB, NTPC & DTL has jointly visited NTPC-Dadri on 27.11.2014 for attending the

problem of PLCC panel. During checking it was found that PLCC panel of both ends are healthy & DT(Direct Trip) was sending from Dadri end to Harsh Vihar end due to wiring problem of 400kV CB (manual trip close circuit). This problem has been rectified now.

2. 210MW unit-4 tripped on overall generator differential protection. 220kV ICT Y-phase CT secondary ckt was faulty (wire got earthed).

3. Time synchronization of DR to be attended at NTPC end. 4.

PSC Conclusions:

1. Red-phase to ground fault occurred in 400kV Dadri-Harsh Vihar ckt2. Red phase breaker

of the line tripped from Dadri end but Harsh Vihar end relay didn’t trip. 400kV Dadri-Harsh Vihar ckt-1 tripped from Dadri end immediately after fault & Harsh Vihar end relay also tripped due to DT received from remote end. 400kV Dadri-Harsh Vihar ckt-1 might

have tripped due to overreaching of distance protection. Fault was continuously feeding through other two phase(Y&B-phase) of ckt-2 as R-phase of the line didn’t trip from Harsh Vihar end. 220/66kV ICT-1 & 3 tripped on backup earth fault protection due to zero sequence current which was fed to the fault from transformers due to presence of tertiary winding.

2. 210 MW unit-4 tripped on overall generator differential protection. 220kV ICT Y-phase CT secondary ckt was faulty (wire got earthed).

3. Harsh Vihar end of 400kV Dadri-Harsh Vihar ckt-2 didn’t sense the fault in any zone. The fault current/Voltage recorded is 1298A/51.23kV which indicates very high impedance about 39ohms. Exact reason couldn’t be concluded. The CT shorting links may be the probable reason. Same has been rectified at Harsh Vihar end.

4. PLCC panel of both ends of 400kV Dadri-Harsh Vihar ckt1 are healthy & DT (Direct Trip) was sent from Dadri end to Harsh Vihar end due to wiring problem of 400kV CB (manual trip close circuit). This problem has been rectified now.

5. There is no back feeding/ interconnections at Harsh Vihar station. 6. DR of Dadri & Harsh Vihar end was not time synchronized.


1. DR of Dadri & Harsh Vihar end needs to be time synchronized. (Action: DTL & NTPC;

Time Frame: 7days) 2. Availability of digital data to be ensured. (Action: DTL & NTPC; Time Frame: 7 days)

PSC-28/T/18:Multiple Element tripping at 400/220kV Muzaffarnagar(UP) station on 9th Oct 2014 at 13:10hrs





Preliminary Report UP Not received

Detailed Report UP Not Received


Fault Clearance Time 960ms As per Pmu data

Phase of the fault Yellow‐phase As per Pmu data



IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; 43.4.C(4) & 43.4.D of CEA Technical Standard for



UP

1. DR/EL, Preliminary report didn’t provide within 24hrs

2. Fault Clearance time more than 160ms for 220kV system

3. Non availability of Bus Bar Protection at 220kV

Muzaffarnagar


1. 220kV Bus Bar differential protection not commissioned at 400/220kV Muzaffarnagar(UP) station.


3. As reported Y-phase Jumper between Bus isolator & circuit breaker of 220kV Muzaffarnagar-Shamli snapped at 220kV Muzzafarnagar s/s. It was bus fault for 220kV Bus of 400/220kV Muzaffarnagar station.

4. Flag details of the tripping is given below:

5. Due to non-availability of bus bar protection all the 220kV elements tripped from remote

end & 400/220kV ICT’s at Muzaffarnagar station tripped on backup over current protection.

6. ICT’s at Muzaffaranagar station tripped on backup over current & earth fault protection due to delayed clearance of fault.

Representative from UP informed the details of the tripping as below-

1. Bus Bar Protection at 400/220kV Muzaffarnagar station has been ordered & would be commissioned by Feb-2015.

2. Implementations of numerical relays are also under process. After implementation DR/EL would be reported to RLDC.

3. Flag details of 220kV Muzaffarnagar-Nara & Muzaffarnagar-Nanauta line may be wrongly noted by station person.

PSC Conclusions: 1. Y-phase Jumper between Bus isolator & circuit breaker of 220kV Muzaffarnagar-Shamli

snapped at 220kV Muzzafarnagar s/s. It was bus fault for 220kV Bus of 400/220kV Muzaffarnagar station. Due to non-availability of bus bar protection, all the 220kV elements tripped from remote end & 400/220kV ICT’s at Muzaffarnagar station tripped on backup over current protection.

2. Delayed Clearance of fault was due to unavailability of bus bar protection at 220kV side of 400/220kV Muzaffarnagar station.

3. Flag details have been received from UP. Preliminary & detailed report along with DR/EL were awaited from UP.

4. Digital data was not available at NRLDC.

PSC Recommendations: 1. Bus Bar Protection at 400/220kV Muzaffarnagar station to be commissioned. (Action:

UPPTCL; Time Frame: 3 months) 2. Implementations of numerical relays & extraction software for numerical relays to be

made available. The activity was reportedly under progress. (Action: UPPTCL; Time Frame: 6 months)

3. Availability of Digital data needs to be ensured. (Action: UPPTCL; Time Frame: 15 days)

PSC-28/T/19Multiple Element tripping at 400kV Chabra station on 10th Oct 2014 at 10:08hrs Event category: GD-1 Generation loss: 480 MW Loss of load: 50 MW Data Summary received to NRLDC:



DR/ EL (From Rajasthan‐Chabra) Rajasthan Not received

Preliminary Report (From Rajasthan‐Chabra) Rajasthan Not received


Fault Clearance Time Not Applicable No fault observed through PMU data

Phase of the Fault Not Applicable No fault observed through PMU data


Detailed Report (From Rajasthan‐Chabra)

Rajasthan Not Received


IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3;

43.4.D of CEA Technical Standard for Construction of Electrical Plants and


Rajasthan


1. Chabra TPS have 3*250MW unit & one unit of 250MW is under construction. 400kV Chabra-Hindaun, Bhilwara & Kawai ckt. Two 220kV lines Chabra-Kawai & Chabra-Jalawar ckt.

2. It was reported telephonically that on 10th Oct 2014 at 10:08hrs, Red-phase jumper of 220kV Chabra-Kawai line snapped and touched to the ground. Distance protection

operated at 220kV Chabra & Kawai end. Due to dip in the voltage auxillary supply to the units also failed. It resulted into tripping of unit-1&2 of Chabra TPS.

3. Fault has not been observed in PMU plot. 4. Digital data of 400kV Chabra, Bhilwara & Kawai station is not available at NRLDC.

Representative from RRVUNL informed the details of the tripping as below-

1. On dated 10 oct 2014 at 10:02 Hrs., R-phase jumper of 220kV Chhabra-Kawai line opened at its wavetrap at Chhabra end and touched to the ground. This line tripped on distance protection and at the same time unit #1 &2 CTPP tripped on loss of their auxiliaries due to dip on voltage at 6.6kV voltage level. No other feeder got tripped due to this event. The setting of under voltage relay of Bus PT is 80% at all 6.6kV auxiliary buses. (PT Ratio 6.9kV/110v).

2. Event log details have been forwarded by Chabra TPS. 3. Some Auxiliary contactor dropped immediately at the time of under voltage (0.8pu). 4. Setting of changeover from UAT to ST (Station Transformer) supply is 4second.

PSC Conclusions:

1. Red-phase jumper of 220kV Chabra-Kawai line snapped and touched to the ground.

Distance protection operated at 220kV Chabra & Kawai end. 2. Due to dip in the voltage auxillary supply to the units also failed. It resulted into tripping of

unit-1&2 of Chabra TPS. 3. As per event log details, relay sent the trip command to the line in 105 ms of sensing the

fault. 4. DR of 220kV Chabra-Kawai line would be helpful to conclude whether fault persisted for

5 seconds or tripping was due to sensitive under voltage setting for auxiliary supply of units at Chabra TPS.

5. Preliminary report, DR/EL & detailed report were awaited from Rajasthan/ Kawai. 6. Availability of digital data needs to be looked into by Rajasthan.

Protection Committee Recommendations:

1. Auxiliary supply might have tripped due to sensitive under voltage setting. It should be

checked & corrected. (Action: RRVUNL; Time Frame: 7 days) 2. Availability of digital data needs to be ensured. (Action: RRVPNL; Time Frame: 15 days) 3. Detailed analysis report of the event & remedial action report to be submitted. (Action:

RRVPNL; Time Frame: 15 days)

PSC-28/T/20:Multiple Element tripping at 400kV Kawai station on 13th Oct 2014 at 16:29hrs Event category: GD-1 Generation loss: 1200MW Loss of load: Nil Data Summary received to NRLDC:



DR/ EL Kawai Received After 24hrs

Rajasthan Received After 24hrs

Preliminary Report Kawai Received After 24hrs

Rajasthan Received After 24hrs

Detailed Report Kawai Not Received

Rajasthan Not Received







43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines;


Rajasthan/ Kawai


1. It was reported that on 13th Oct 2014 at 16:29hrs, there was fault in 400kV Chabra-Bhilwara line. Further it was also reported that DT received to both Chabra & Bhilwara end.

2. Binary Output of Numerical Relay (7SA52 & 7SA6), at Chabra end which is used to Operate SPS operation was assign only for Distance Protection and over voltage Protection since No over Voltage at Chabra end and no Distance Protection Operate hence this binary output (BO) not become high on DT receive as a result of it SPS Scheme didn’t operate & unit-1 of CTPP didn’t trip. All the running unit became in running condition.

3. After tripping of 400kV Chabra-Bhilwara ckt, SPS for over power protection of 400kV Kawai-Bassi line operated. It tripped unit number-2 at Kawai station

4. After tripping of one line from Chabra, line flow on 400kV Kawai-Chabra line reversed. It became Chabra to Kawai & there was old logic on the line that if power flow becomes less than 10MW on this line then SPS would be operated for under power protection & trip the machine automatically.

5. Fault has not been observed in PMU plot. 6. Digital data of 400kV Chabra, Bhilwara & Kawai station is not available at NRLDC. 7. Extract of SPS related recommendation in RPC committee report for multiple element

tripping in Chabra/ Kawai/ Kalisindh Complex is mentioned below:

SE (O)-NRPC stated that one committee was formed to analyse the multiple element tripping in Kawai-Chabra-Kalisindh complex. Recommendations has also issued on behalf of discussion in the committee meeting. Implementation of those recommendations by RRVUNL/RRVPNL is still awaited. RRVPNL representative informed that now connectivity has been changed & SPS of Chabra/Kawai complex needs to be reviewed.

PSC Conclusions:

1. There was fault in 400kV Chabra-Bhilwara line. SPS logic at Chabra end trips the unit in

case of operation of DPR, LBB protection at Chabra end. As in this tripping, DT was received at Chabra TPS but it didn’t trip unit-1. After tripping of 400kV Chabra-Bhilwara

ckt, SPS for over power protection of 400kV Kawai-Bassi line operated. It tripped unit number-2 at Kawai station

2. After tripping of one line from Chabra, line flow on 400kV Kawai-Chabra line reversed. It became from Chabra to Kawai & there was old logic on the line that if power flow becomes less than 10 MW on this line then SPS would be operated for under power protection & trip the machine automatically.

3. Digital data of Kawai/Chabra was not available at NRLDC. 4. Kawai has informed telephonically that PLCC would be implemented in 400kV Chabra-

Kawai line till Dec-2014. 5. Preliminary report, DR/EL had been received from Rajasthan/ Kawai but detailed report

was awaited from Rajasthan/ Kawai


1. With change in the network configuration in the area there is a need to review the SPS scheme. RRVPNL would review the SPS meant for Kawai-Chhabra complex and submit the same to NRPC for approval.(Action: RRVPNL, Time Frame: 01 month

2. SPS logic of under power protection for 400kV Chabra-Kawai line at Kawai end needs to be checked & corrected. (Action: APL; Time Frame: 7days)

3. SPS logic at Chabra end needs to take care all type of tripping of line for example any protection operation, DT, hand tripped, Bus bar & LBB. (Action: RRVUNL, RRVPNL; Time Frame: 7 days)

4. Availability of digital data needs to be checked & made available at NRLDC. (Action: RRVUNL, APL, RRVPNL; Time Frame: 7 days)

PSC-28/T/21:Multiple Element tripping at 400kV Gorakhpur(UP) station on 14th Oct 2014 at 08:19hrs Event category: GD-1 Generation loss: 87MW Loss of load: 170MW Data Summary received to NRLDC:


Availability of Digital Data (SCADA Data) Partial Available Error in SoE


NTPC Received At the time of meeting



Detailed Report

UP Received Partial Report




Phase of the Fault R‐phase then in Y‐phase As per PMU data




43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric

Lines; CEA Grid Standard 15.4 CEA Grid Standard 3.1.e

UP, NTPC

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Fault clearance time more

than 160ms


1. In antecedent condition at 400/220kV Gorakhpur (UP) station, Bus-Bar differential protection is out of service and all the 400kV elements are on Bus-II and Bus-I is under shutdown due to commissioning of new 315 MVA transformers.


3. It has been reported by UPPTCL site that at 08:19 hrs on 14.10.2014, a fault took place simultaneously on both 220 KV Tanda-Sultanpur and Tanda-Gorakhpur lines (lines are on same towers) & fault was at some distance from Tanda TPS.

4. At 220 KV S/S Sultanpur, CB tripped on fault. At 220kV S/S Gorakhpur, delayed tripping occurred. 220kV Gorakhpur4- Gorakhpur2 ckt- I & II did not trip and therefore the fault was reflected on 400/220kV Gorakhpur (UP) Bus.

5. This resulted in tripping of all the 400kV elements at 400kV S/S Gorakhpur due to operation of 96 relay (Bus Bar/ LBB Protection).

6. However, 400kV Gorakhpur-Gorakhpur (PG)-II line did not trip on Bus Bar/ LBB protection operation at 400kV Gorokahpur(UP).

7. At Tanda T.P.S., Generating unit no. I (110 MW) also tripped during this fault. 8. Flag details of the tripping is mentioned below:

Points for discussion in the meeting: 1. Delayed clearance of fault needs to be looked into. 2. Non-operation of main & back up protection in 220kV side of 400/220kV Gorakhpur(UP)

needs to be looked into. 3. Non-operation of main & back up protection at 220kV Tanda TPS needs to be looked

into. 4. Operation of Bus Bar Protection at 400kV Gorakhpur (UP) station needs to be looked

into. 5. Non-tripping of 400kV Gorakhpur(UP) to Gorakhpur(PG) ckt 2 on Bus Bar Protection

needs to be looked into. 6. Breaker opening time at 220kV Gorakhpur (Barhua) end of 220kV Gorakhpur-Tanda line

needs to be checked & corrected. 7. Bus Bar/ LBB scheme needs to be checked & corrected. 8. Availability of digital data needs to be ensured. 9. Tripping of generating unit at Tanda(TPS) needs to be looked into. Which protection

operated for the unit? 10. Availability of Numerical relay to be ensured by UPPTCL/ NTPC. 11. Availability of two main & backup protection at 220kV level needs to be ensured by

UPPTCL/NTPC. 12. Availability of DR/EL needs to be ensured by UPPTCL/ NTPC

Representative from UPPTCL informed the details of the tripping as below:

1. Delayed clearance of fault was due to delayed opening of breaker at 220kV Gorakhpur (Barhua) station.

2. Protection of 220kV Barhua-Tanda line checked. Service engineer of firm of circuit breaker has been called for overhauling.

3. Protection of 220kV Gorakhpur-Barhua ckt-I & II have been checked & corrected. 4. Bus Bar Protection had mal-operated at 400kV Gorakhpur(UP) i.e. Bus Bar Protection at

Gorakhpur(UP) was out of service in antecedent condition. Bus Bar Protection would be replaced.

5. Bus Bar protection tendering & allotement has been completed for eight 400kV sub-station in UP. Name of the stations are: 400kV Muradngar, Muzaffarnagar, Greater Noida, Gorakhpur, Sultanpur, Sarnath & Azamgarh station.

6. Bus Bar Protection at 400kV Gorakhpur(UP) would be implemented within 6 month.

7. Availability of digital data at 220kV Gorakhpur-Barhua and 400kV Gorakhpur checked & found ok.

8. Requirements of balance Numerical relays send to Head quarter and procurement is in process.

9. One main & backup protection is installed at 220kV levels. Head Quarter is requested for providing another one main & backup protection.

10. Requirement of DR/EL has been sent to Head Quarter and the same will be commissioned after delivery & installation.

11. Operation of Bus Bar Protection at 400kV Gorakhpur (UP) station needs to be looked into.

Representative from NTPC informed the details of the tripping as below:

1. Tanda TPS Unit was running at 87MW. Due to disturbance in 220kV system, Sultanpur-1 & Gorakhpur line tripped. Due to sudden jerk in the system, Unit#l tripped on "Axial Shift Hi" protection, along with many drives in off-site areas. Prior to tripping all turbine parameters were normal.

2. After tripping of Unit, on checking of SOE it was found that all the three channels of turbine axial shift high logged. In the alarm log of FSSS DDC all the three channels of turbine trip appeared and subsequently boiler tripped on turbine trip. The print out of the SOE and axial shift trend could not be taken as there was power supply failure for the HMI due to supply interruption In UPS.

3. On checking it was found that all the incomers to UPS had failed and battery backup did not provide any backup. These batteries are due for replacement.

4. Flag details of the Tanda-Sultanpur line & Tanda-Gorakhpur(Barhua) line is given below:

Remedial action to be taken (As per UP Report):

1. At 400 KV S/S Gorakhpur, Bus Bar protection needs to be put in service immediately. (Action UPPTCL)

2. At 400 KV S/S Gorakhpur, Line Distance Protection Relay of 220 KV Gorakhpur (400)-Gorakhpur (220)- I & II needs to be checked. (Action UPPTCL)

3. At 220 KV S/S Gorakhpur (Barahua), circuit breaker (of Tanda line) needs to be checked. (Action UPPTCL)

PSC Conclusion:

1. It was concluded from available information that a fault took place simultaneously on both 220 KV Tanda-Sultanpur and Tanda-Gorakhpur(Barhua) lines (lines are on same towers) & fault was at some distance from Tanda TPS. At 220 KV S/S Sultanpur, CB tripped on fault. At 220kV S/S Gorakhpur, delayed tripping occurred. 220kV Gorakhpur4- Gorakhpur2 ckt- I & II did not trip and therefore the fault was reflected on 400/220kV Gorakhpur (UP) Bus.

2. Delayed clearance of fault was due to delayed opening of breaker at 220kV Gorakhpur (Barhua) station. Service engineer of firm of circuit breaker had been called for overhauling

3. Bus Bar Protection at 400kV Gorakhpur(UP) was out of service because of earlier mis-operation of bus bar protection. It would be implemented within 6 months.

4. Only One main & backup protection was installed at 220kV Gorakhour(Barhua), Sultanpur, 220kV side of 400/220kV Gorakhpur(UP) station instead of two main & backup protection.

5. Tanda TPS unit tripped on Axial Shift High. At the same time all the incomers to UPS had failed and battery backup did not provide any backup.

6. Fault was observed in Y&B-phase of both Tanda-Gorakhpur line & Tanda-Sultanpur line & all three phase of the line tripped.

7. 220kV lines of UP have electro-mechanical relays instead of numerical relays. 8. Sequence of Event couldn’t be finalized due to non-availability of NR SoE, DR/EL data

from the site 9. Preliminary Report, Flag details & Detailed report had been received from UP. It was

reported in detailed report that printout of DR/EL details was not available


1. Bus Bar Protection to be corrected at 400kV Gorakhpur(UP) station. (Action: UPPTCL; Time Frame: 3 month)

2. Electromechanical relay of 220kV lines to be replaced by Numerical relay. (Action: UPPTCL; Time Frame: 6 month)

3. Breaker of 220kV Tanda-Gorakhpur(Barhua) line to be overhauled. (Action: UPPTCL; Time Frame: 2 month)

4. Two main & back up protection to be implemented in 220kV lines from 220kV Sultanpur, Gorakhpur (400/220kV) & 220kV Gorakhpur(Barhua) station.

5. Availability of digital data at NRLDC to be ensured (Action: UPPTCL; Time Frame:15 days)

6. Battery bank at 220kV Tanda TPS to be replaced. (Action: NTPC; time Frame: 1 month) 7. Availability of DR/EL & Downloading Software for extraction of DR/EL to be ensured.

(Action: UPPTCL; Time Frame: 1 month)

PSC-28/T/22:Multiple Element tripping at 400kV Gorakhpur(PG) station on 14th Oct 2014 at 09:20hrs Event category: GI-2 Generation loss: Nil Loss of load: Nil Data Summary received to NRLDC:


Availability of Digital Data (SCADA Data) Available

DR/ EL POWERGRID Received After 24hrs

Preliminary Report POWERGRID Received After 24hrs

Detailed Report POWERGRID Not Received



Phase of the Fault Y‐B & R‐Y phase to phase fault As per PMU data



IEGC 5.2.r & 5.9.6.c (VI);

CEA Grid Standard 15.3;


CEA Grid Standard 3.1.e

POWERGRID 1. DR/EL, Preliminary report didn’t

provide within 24hrs 2. Fault clearance time more than 100ms


1. In antecedent condition there was heavy rainfall and storm in that area. 2. 400kV Gorakhpur(PG)-Muzaffarpur(PG) D/C tripped due to phase to phase fault. 3. As per DR/EL of 400kV Gorakhpur(PG) end 400kV Gorakhpur(PG)-Muzaffarpur ckt-1

tripped on Y-B phase to phase fault. 400kV Gorakhpur(PG)-Muzaffarpur ckt-2 tripped on R-Y phase to phase fault. As fault was phase to phase, it resulted into tripping of all 3-phase of the line in zone-1 timing. Both lines tripped from Muzaffarpur end on carrier received from Gorakhpur(PG) end.

4. 400kV Gorakhpur(PG)-Muzzafarpur ckt-1: a. fault current Ia= 2.32kA, Ib= 8.93kA, Ic=8.16kA

5. 400kV Gorakhpur(PG)-Muzzafarpur ckt-2: a. fault current Ia= 8.64kA, Ib= 12.78kA, Ic=2.93kA

6. Inferences on behalf of details available with NRLDC: As per PMU data & DR/EL it seems that command has sent by the distance

protection immediately but breaker may be opened with some time delay. As some voltage & current is showing in the DR.

POWERGRID representative informed the house about the event: 1. Earth wire snapped and fall on both the tower of line & both t 400kV Gorakhpur-

Muzaffarpur line tripped on phase to phase fault. 2. Fault has cleared from both the end within 100ms as per DR. Slight voltage may be

persisted due to resonance phenomena. Representative from NRLDC stated that Resonance or transient phenomena couldn’t result into dip in the voltage for 500ms at Balia, Dadri & Agra PMU voltages. PSC Conclusions:

1. Earth wire snapped and fall on both the tower of line & both t 400kV Gorakhpur-Muzaffarpur line tripped on phase to phase fault. Line distance protection got clear the fault within 100ms.

2. Reason of dip in the phase voltages of Balia PMU for 560ms couldn’t be finalised. PSC Recommendations: Breaker opening time at Gorakhpur(PG) & Muzaffarpur(PG) end needs to be checked. (Action: POWERGRID; Time Frame: 15 days)

PSC-28/T/23:Tripping of Balia-Bhiwadi Bipole on 16th Oct 2014 at 02:00hrs Event category: GI-2

Generation loss: Nil Loss of load: NIl Data Summary received to NRLDC:



Not Available



Detailed Report POWERGRID Received





Violation of Clauses IEGC 5.2.r ;

CEA Grid Standard 15.3; POWERGRID



1. On 16 Oct 2014 early in the morning at 02:00hrs, bipole was running at minimal power flow i.e.250MW.

2. 400kV Moga-Bhiwadi ckt-2 was opened for voltage regulation from other end that sent DT signal at Bhiwadi end for intended opening of the line. However, one of the phases of the tie breaker got stuck which caused LBB protection of the tie breaker and both main breaker on that bay also opened. Consequently, AC filter-2 bank of HVDC got tripped. Other available filters could not be switched on because of overvoltage filter switching inhibit from pole control.

3. Hence the minimum filter requirement of HVDC could not be fulfilled causing HVDC bipole to trip from station control

4. SoE of Bipole tripping & opening of breaker of Moga & Bhiwadi end of 400kV Moga-Bhiwadi ckt2 was not captured.

5. DR/EL for 400kV Moga- Bhiwadi ckt2 & Event logger data of 400kV Bhiwadi AC station are required for further analysis.

POWERGRID representative informed the house about corrective action: 1. Instruction has sent to Moga & Bhiwadi station that in case of manual opening, it would

be done from Bhiwadi end & DT would be sent to Moga end. 2. In case of opening of 400kV Moga-Bhiwadi ckt on high voltage, POWERGRID would

preferably open ckt-1 because this line has lower over voltage setting compare to ckt-2. 3. Modification in Overvoltage filter switching inhibit scheme was discussed with ABB &

Siemens. They are not agreed on this purposal & it couldn’t be changed. PSC Conclusions:

1. 400kV Moga-Bhiwadi ckt-2 was opened for voltage regulation from other end that sent DT signal at Bhiwadi end for intended opening of the line. However, one of the phases of the tie breaker got stuck which caused operation of LBB protection of the tie breaker and both main breakers on that bay also got opened. Consequently, AC filter-2 bank of HVDC got tripped. Other available filters could not be switched on because of ‘overvoltage filter switching inhibit’ from pole control.

2. Hence the minimum filter requirement of HVDC could not be fulfilled causing HVDC bipole to trip from station control.

3. In case of manual opening or high voltage opening, it is preferred that 400kV Moga-Bhiwadi ckt-1 to be opened first & that too from Bhiwadi end.

4. Overvoltage filter switching inhibit scheme cannot be modified in the opinion of Siemens. PSC-28/T/24:Complete outage of Kota TPS on 16th Oct 2014 at 16:30hrs Event category: GD-1 Generation loss: 640 MW Loss of load: Nil Data Summary received to NRLDC:



DR/ EL Rajasthan Not Received

Preliminary Report Rajasthan Received After 24hrs

Detailed Report Rajasthan Received






CEA Grid Standard 15.3; Rajasthan


Extract of Detailed report received from KTPS is mentioned below:

Representative from RRVUNL stated corrective action on time grading between various 6.6 kV feeders and tie arrangements for 6.6 kV stations Buses had already been taken at Kota TPS. This is for the information of the members.

PSC-28/T/25:Multiple Element tripping at 220kV Salal HEP station on 18th Oct 2014 at 07:40hrs Event category: GD-1 Generation loss: 100MW Loss of load: 50MW

Data Summary received to NRLDC:



DR/ EL NHPC Received After 24hrs


Detailed Report NHPC Not Received

Description Fault info Remarks

Fault Clearance Time Not Available

Phase of the Fault Not Available



CEA Grid Standard 15.3; NHPC



IEGC 5.2.r ; CEA Grid Standard 15.3; 43.4.D of CEA Technical


Lines; CEA Grid Standard 15.4

J&K 1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Healthiness of DR/EL


1. Unit-3, 4 & 5 were running at 07:00hrs on 18th Oct 2014. Due to schedule & less inflow unit 5 was planned to stop, subsequently stop command was given from the Salal control room at ~07:50hrs for stopping of unit-5.

2. B-phase pole of unit-5 CB didn’t open, resulting in the operation of the LBB relay & isolation of Bus-B.

3. All feeders and Generator (Unit-3, Unit-4, Unit-5, Salal Kishenpur-I & II and Salal-Jammu ckt1) connected with Bus B tripped due to LBB operation.

4. Details received from NHPC is given below:

NHPC representative informed the house about corrective action: 1. Control valve assembly of SF6 CB was faulty. Same has been replaced at the time of

tripping. SF6 breaker of unit-5 is ten year old & over hauling of the breaker would be done in annual maintenance.

2. Incident occurred at Salal HEP on 25th Sep 2014, at that time there was problem in MOCB of unit-2. It would be replaced with SF6 breaker in Annual maintenance till Jan-2015. All the other breaker at Salal HEP are SF6 breaker.

PSC Conclusions:

1. Unit-3, 4 & 5 were running at 07:00hrs on 18th Oct 2014. Due to schedule & less inflow, unit 5 was planned to be stopped. Subsequently stop command was given from the Salal control room at ~07:50hrs for stopping of unit-5. B-phase pole of unit-5 CB didn’t open, resulting in the operation of the LBB relay & isolation of Bus-B. All feeders and Generator (Unit-3, Unit-4, Unit-5, Salal Kishenpur-I & II and Salal-Jammu ckt1) connected with Bus B tripped due to LBB operation.


1. Over hauling of SF6 breaker of unit-5 need to be done. (Action: NHPC; Time Frame:1 month)

2. MOCB of unit-5 to be replaced with SF-6 breaker. (Action: NHPC; Time Frame: Till Jan-2015)

PSC-28/T/26: Multiple Element tripping at 400/220kV Muradnagar station on 21st Oct 2014 at 15:51hrs Event category: GD-1 Generation loss: Nil Loss of load: 570MW Data Summary received to NRLDC:



Not Available



Detailed Report UP Received



Phase of the fault Blue‐phase As per PMU data



IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; 43.4.D of CEA Technical


Lines; CEA Grid Standard 15.4 CEA Grid Standard 3.1.e

UP

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Fault Clearance time is

more than 160ms


1. In antecedent condition 315MVA ICT-2 was under shut down. 2. It has been reported by UPPTCL site that at 220kV S/S Muradnagar, B-phase lightening

arrestor of 220 KV Muradnagar(400)-Muradnagar (220) inter connector damaged, which resulted in tripping of the above line at both the ends.

3. Simultaneously 400/220kV, 315 MVA, ICT-I & III tripped at 400kV S/S Muradnagar. 4. Delayed clearance of fault has observed through PMU data. 5. Digital data of muradnagar station is not available at NR SoE

UPPTCL representative briefed the house about the event:

1. As 220 KV Muradnagar(400)-Muradnagar (220) inter connector is radial feeder thatswhy zone-2 setting has changed to zero instead of 0.4second & backup earth fault setting has changed to 0.2 instead of 0.3

2. 400/220kV ICT-1&3 tripped on backup earth fault/over current protection. 3. Tripping of 220kV Sahibabad-Muradnagar in Zone-4(As per flag details) is under

investigation.

PSC Conclusions: 1. At 220kV S/S Muradnagar, B-phase lightening arrestor of 220kV Muradnagar(400)-

Muradnagar (220) inter connector got damaged, which resulted in tripping of the above line from both the ends.

2. Distance protection setting & backup earth fault protection setting was delayed. 3. As 220 KV Muradnagar(400)-Muradnagar (220) inter connector is radial feeder thats why

zone-2 setting has been changed to zero instead of 0.4second & TMS of backup earth fault setting has been changed to 0.2 instead of 0.3.

4. 400/220kV, 315 MVA, ICT-I & III of Muradnagar station had tripped on backup earth fault/ over current protection.

5. Delayed clearance of fault was due to failure of main & backup protection in 220kV Muradnagar(400)-Muradnagar (220) inter connector line.

6. Exact SoE couldn’t be finalized due to non-availability of DR/EL. Numerical relays would be helpful in analyzing the event.

7. Data of disturbance recorder & Event recorder was not available at UPPTCL. 8. Tripping of 220kV Sahibabad-Muradnagar in Zone-4(As per flag details) was wrong

operation. 9. At 400kV S/S Muradnagar, the time setting co-ordination was not proper between line

Distance Protection of 220 KV Muradnagar (400)-Muradnagar (220) line and 315 MVA, ICTs.


1. Electromechanical relay of ICT’s & 220kV lines should be replaced with Numerical relay. (Action: UPPTCL; Time Frame: 3 month)

2. Downloading Software for extraction of DR/EL to be ensured. (Action: UPPTCL; Time Frame: 1 month)

3. Tripping of 220kV Sahibabad-Muradnagar in Zone-4(As per flag details) need to be checked & corrected. (Action: UPPTCL; Time Frame: 1 month)

4. Availability of digital data of Muradnagar station needs to be ensured. (Action: UPPTCL; Time Frame: 15 days)

5. At 400kV S/S Muradnagar, the time setting co-ordination between line Distance Protection of 220 KV Muradnagar (400)-Muradnagar (220) line and 315 MVA, ICTs needs to be checked and attended. (Action: UPPTCL; Time Frame: 1 month)

B2. Multiple elements tripping in Uttar Pradesh:

Large number of tripping occurred in UP system. In 2013 total multiple element tripping was 47 & 51 is in 2014(till 18th Nov 2014). The major problem area in UP is tabulated below:

Name of the station Nos of times multiple element

tripping (Year-2014)

400kV Muradnagar 8

400kV Agra(UP) 8

400kV Azamgarh 5

400kV Sarnath 5

400kV Paricha 4

400kV Gorakhpur(UP) 3

400kV Anpara 3

400kV Unnao 3

400kV Muzaffarnagar 2

400kV Lucknow(UP) 2

Such tripping are reflection of inadequacy/unresponsiveness of protection and other safety measures in the UP state system. Following reasons are the major contributor for large number of tripping:

Delayed Clearance of Fault. Bus Bar Protection at 400kV & 220kV is either not available or unhealthy. Local Breaker Back-up Protection at 400kV & 220kV is either not available or unhealthy Non-availability of Main-II protection at 220kV lines Non-availability of DR/EL either due to electro-mechanical relays or extraction tool is not

available at many places. Protection coordination Problem at a station. Lacking of skilled Man power O&M Practices Improper load management Human Error

Representative of UPPTCL agreed to take necessary steps to avoid these tripping.

B.3. Multiple element tripping at 400/220kV Sarnath Station:

A total of 11 nos. of multiple trippings had occurred up to 07th December, 2014 in and around 400 kV Sarnath sub-station of UPPTCL. Further there had been instances of trippings in December, 2014 with 02 trippings on 06th Dec, one on 7th and one on 08th Dec. The summarised details were enclosed as Annex-XI of the agenda

UPPTCL was requested to explain the reasons of so many tripping in Sarnath sub-stations in December, 2014. Representative of UPPTCL informed that there were problems with the Back Up protection and same had been rectified. UPPTCL was requested to submit the details of action taken to avoid the recurrences of these types of incidents.

B.4. Violation of protection standard in case of tripping of Inter Regional Lines of voltage class 220 kV and above level network of Northern Region

It has been observed that many of the lines trip on single phase to earth fault without attempting auto-reclosure. According to CEA Technical standard for construction of electric plants and electric lines —Clause 43(4) (c), transmission lines of 220 kV and above should be having single phase auto-reclosing facility for improving the availability of the lines. However, from the tripping details, it is evident that many 220 kV lines including Inter-regional lines do not have auto-reclosure facility at present either at one end or at both ends. Representative of NRLDC stated that they have repeatedly requested for implementation of Auto Reclosure facility in these lines & for providing the DR/EL of the tripping within 24 hours of the events as per IEGC clause 5.2.r and CEA grid standard 15.3.

S. No.Name of Transmission Element

TrippedOwner/ Utility Date Time Brief Reason/Relay Indication

Fault Clearance Time(>100 ms for

400 kV and 160 ms for 220 kV)

FIR Furnished

(Y/N)

DR/EL

provided in

24 hrs

Remarks

1 220 kV BADOD‐MODAK Rajasthan 8‐May‐14 11:33 B Phase to Earth Fault No Yes No No A/R Facility

2 220 kV AURAIYA‐MALANPUR NTPC 12‐May‐14 17:20 Bus fault at Auraiya No Yes No

3 220 kV AURAIYA‐MAHEGAON NTPC 12‐May‐14 17:20 Bus fault at Auraiya No Yes No

4 220 kV BADOD‐KOTA Rajasthan 18‐May‐14 15:54 Y‐B Phase Fault No Yes No No A/R Facility

5 220 kV BADOD‐KOTA Rajasthan 19‐May‐14 13:23 B Phase to Earth Fault No Yes No No A/R Facility

6 220 kV AURAIYA‐MAHEGAON NTPC 9‐Jun‐14 4:40Overcurrent , Earth Fault protection operated at

MehgaonNo Yes No

7 220 kV AURAIYA‐MALANPUR NTPC 12‐Jun‐14 17:01 R Phase to Earth Fault No Yes No No A/R facility



10 220 kV AURAIYA‐MALANPUR NTPC 3‐Jul‐14 10:05 Tripped from Malanpur No Yes No No A/R facility

11 220 kV AURAIYA‐MALANPUR NTPC 10‐Jul‐14 21:13 R Phase to Earth Fault No Yes No No A/R facility

12 220 kV BADOD‐KOTA Rajasthan 11‐Jul‐14 15:48 R Phase to Earth Fault No Yes No No A/R facility

13 220 kV AURAIYA‐MALANPUR NTPC 25‐Jul‐14 11:53 Fault in Zone 3 , Delayed Fault in NR Yes Yes No Fault in NR with delayed Fault clearance

14 220 kV AURAIYA‐MAHEGAON NTPC 25‐Jul‐14 11:53 Fault in Zone 3 , Delayed Fault in NR Yes Yes No Fault in NR with delayed Fault clearance

15 220 kV AURAIYA‐MALANPUR NTPC 12‐Aug‐14 3:57 R Phase to Earth Fault No No No

16 220 kV AURAIYA‐MAHEGAON NTPC 15‐Aug‐14 22:14 R Phase to Earth Fault No No No

17 220 kV AURAIYA‐MAHEGAON NTPC 16‐Aug‐14 2:32 R Phase to Earth Fault No No No

18 220 kV AURAIYA‐MALANPUR NTPC 17‐Aug‐14 3:40 R Phase to Earth Fault No No No

19 220 kV AURAIYA‐MALANPUR NTPC 26‐Aug‐14 18:50 Tripped from Auraiya end No No No

20 220 kV AURAIYA‐MALANPUR NTPC 28‐Aug‐14 1:35 R Phase to E/F, Breaker stuck Yes No No

21 220 kV AURAIYA‐MAHEGAON NTPC 28‐Aug‐14 1:35R Phase to earth fault due to delayed fault clarance

at MalanpurYes No No

22 220 kV BADOD‐KOTA Rajasthan 30‐Aug‐14 13:22 R Phase to Earth Fault No No No

23 220 kV BADOD MODAK Rajasthan 10‐Sep‐14 19:42BADOD END ‐Z3, RYB, 114KM AND MODAK END ‐

RYB ,Z1,32.5KMYes Yes No

Rajasthan end has isolated the line from modak bus

resulting it in a longer line . This has caused the fault on

line in zone 3 from Badod end.

24 220 kV BADOD‐KOTA Rajasthan 29‐Sep‐14 11:50 B PHASE TO EARTH FAULT ‐ Yes No No Autoreclosure facility on Line at Kota End

25 220 kV BADOD‐KOTA Rajasthan 29‐Sep‐14 14:58 B PHASE TO EARTH FAULT ‐ Yes No No Autoreclosure facility on Line at Kota End

5 220 kV BADOD MODAK Rajasthan 21‐Oct‐14 22:24 Tripped at Modak. NO No No

26 220 kV AURAIYA‐MALANPUR NTPC 11‐Nov‐14 3:43 R Phase to earth Fault No yes No A/R installed at both end and is in service.

27 220 kV AURAIYA‐MALANPUR NTPC 23‐Nov‐14 23:38 B Phase to earth Fault No yes No

28 220 kV BADOD‐MODAK Rajasthan 23‐Nov‐14 5:12 Tripped on modak end ‐ yes No A/R to be installed at Modak end

S. No. Name of the line tripped No. of tripping Utility

1 220 kV AURAIYA‐MALANPUR 13

2 220 kV AURAIYA‐MAHEGAON 6

3 220 kV BADOD‐KOTA 6

4 220 kV BADOD‐MODAK 4

NTPC

Rajasthan As seen from the above table, there had been frequent instances of tripping of 220kV Modak-Badod, 220kV Kota-Badod, 220kV Auraiya-Malanpur and 220kV Auraiya-Mehgaon in recent past. It was mentioned during discussion on the tripping of 11th Nov 2014 that auto-reclosure of both end of

Auraiya & Malanpur, Mehgaon has been operationalized but in the tripping of 5th Dec 2014, it seemed that line didn’t autoreclose. PMU of the tripping is given below for reference:

NTPC representative informed that there was problem in auto recloser of 220kV Auraiya-Malanpur & Auraiya-Mehgaon line. One joint meeting of NTPC & MPPTCL was scheduled on 22nd Dec 2014. He assured that gist of the discussions would be informed to NRPC and NRLDC. The status of Auto-recloser of Badod-Kota & Modak-Badod was to be updated by RVPNL Representative from NRLDC stated that in case of single inter-regional element tripping, constituents should have submitted DR/EL & detailed report of the tripping. These tripping & violations are continuously monitored by CERC. NLDC is submitting monthly report of violation in case of inter-regional tripping to CERC and CEA.

Additional Agenda:

Following are the Grid Incidents from August to October, 2014 in Northern Region. Tripping without load loss mentioned in Additional Agenda. Utilities were requested to submit detailed report/action taken to avoid recurrences of these incidents

a. Multiple Element tripping at 400kV Makhu station on 11th Aug 2014 at 12:08hrs

Event category: GI-2 Generation loss: Nil Loss of load: Nil Data Summary received to NRLDC:



DR/ EL Punjab Not received

Preliminary Report Punjab Not received

Detailed Report Punjab Not received



Phase of the Fault Blue‐Phase As per PMU data



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; Punjab



Punjab

Based on above information description of the events is:

1. It was reported that internal short ckt has occurred in Blue phase CT. Bus Bar differential protection operated at 400kV Makhu station. 400kV Rajpura-Makhu ckt tripped due to operation of bus bar protection. At the same time 400kV Makhu-Nakodar ckt also tripped.

2. Fault Clearance time was ~320ms & max dip in Blue-phase. 3. 400kV Makhu station have one an half breaker scheme..

Points for Discussion:

1. In case of one an half breaker scheme, line may not be tripped in case of operation of bus bar protection until tie CB is not available in the bay.

2. Reason of delayed clearance of fault needs to be looked into. (Bus bar Protection may clear the fault within 200ms).

3. Tripping of 400kV Makhu-Nakodar ckt needs to be looked into. 4. It was discussed in 28th June tripping at Makhu in 27th PSC that bus bar scheme of

400kV Makhu station had some error. Same had been rectified. 5. Reason of delayed clearance of fault needs to be looked into. (Bus bar Protection may

clear the fault within 200ms). 6. Availability of digital data needs to be looked into

Preliminary Report, DR/EL & Detailed Report from Punjab was to be received. PSTCL was advised to elaborate the incident & submit the detailed report covering the “points for Discussion” above and also indicating corrective actions already taken/being taken (within time line) to avoid such events

b. Multiple Element tripping at 400/220kV Panchkula(PG) station on 22nd Aug 2014 at 10:36hrs








Detailed Report POWERGRID Received (Partially) After 24hrs



Fault Clearance Time

Not observed As per PMU data

Phase of the Fault

Not observed As per PMU data; However as reported R‐phase conductor

snapped



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; POWERGRID, Haryana

CEA Grid Standard 15.3 POWERGRID,



Haryana


1. It was informed telephonically, that at 400kV Panchkula S/S, R-phase jumper of 220kV Panchkula-Raiwali ckt-1 (202bay) snapped from wave trap end at 400/220kV Panchkula station, Later on fire catched by wave trap. 400kV ICT-1&2 tripped from 220kV side of ICT’s on earth fault protection.

2. 220kV line jumper of R-phase form wave trap opened, broken conductor condition, No earth fault occurred, Due to heavy load in line ~550A in Y & B phase and no current in R-phase, unbalance current created ICT-1 & 2 Neutral current. The CT ratio in ICT-2 MV B/U EF relay was wrongly entered as 2000/1 instead of 800/1 due to which it sensed EF current of ~420A (instead of actual 180A) and tripped in 4.17 sec. After this ICT-1 sensed earth fault current ~300A and tripped after ~15 sec.

3. No fault observed in PMU data. NR SoE is given below:

4. Probable Sequence of tripping is mentioned below:

5. As per NR SoE & DR, 400/220kV ICT-2 was tripped on direct earth fault from both sides

simultaneously at 10:36:53.307hrs. But 400/220kV ICT-1 was tripped after~15 sec. i.e.at 10:37:08.520hrs.

6. As per DR/EL 220kV Panchkula-Raiwali ckt-2 tripped at 10:52:08.681hrs.


1. Tripping of 315MVA ICT-1 need to be relooked into. 2. Delayed tripping of ICT-1 needs to looked into. 3. As per DR/EL of 220kV Panchkula-Raiwali line, at 10:36:54.455hrs R-phase current

raised. It needs to be looked into. 4. As per DR/EL of 220kV Panchkula-Raiwali line, the neutaral current is high. It is

~419amp but earth fault protection did not operate. It needs to be looked into. 5. Statement in the report “The CT ratio in ICT-2 MV B/U EF relay was wrongly entered as

2000/1 instead of 800/1 due to which it sensed EF current of ~420A (instead of actual 180A) and tripped in 4.17 sec” to be relooked.

6. Reason of shifting of neutral current in Red-phase for 220kV Raiwlali feeders & 400/220kV ICT’s needs to be looked into.

Preliminary report, DR/EL had been received from POWERGRID but detailed report was awaited. DR/EL & Report was awaited from Haryana. POWERGRID and HVPNL were advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events.

c. Tripping of 220kV Auraiya-Malanpur & Auraiya-Mehgaon ckt on 28th Aug 2014 at 01:37hrs Event category: GD-1 or GI-1 Generation loss: Nil Loss of load: Nil (UP may confirm) Data Summary received to NRLDC:



DR/ EL NTPC Not received

Preliminary Report NTPC Not received

Detailed Report NTPC Not received






IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; NTPC




NTPC


1. 220kV Auraiya-Malanpur & 220kV Auraiya-Mehgaon tripped on R-phase to earth fault. 2. Max dip in Red phase and fault persisted for 6000ms (01:37:01.600hrs to

01:37:07.600hrs). 3. Delayed clearance of fault from Auraiya, Malanpur & Mehagaon end. 4. It seems from PMU data that some load loss has been occurred in the system. Rise in

frequency of ~0.05Hz observed, indicating load loss~250MW in the grid. 5. Sequence of Event didn’t capture in NR SoE.


1. Delayed clearance of fault to be looked into. 2. Availability of Digital data needs to be looked into.

A letter dated 29th Aug 2014 had also written to NTPC-Auraiya by NRLDC but details of the tripping were to be received. DR/EL, Preliminary along with Detailed report from NTPC was to be received. NTPC was advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events.

d. Tripping of 400kV Jhajjar-Mundka D/C on 29st Aug 2014 at 21:01hrs




DR/ EL APCPL Not received

Delhi Not received

Preliminary Report APCPL Not received

Delhi Not received

Detailed Report APCPL Not received

Delhi Not received






IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; APCPL, Delhi



APCPL, Delhi


1. 400kV Jhajjar-Mundka D/C tripped from Mundka station due to DC supply failure at 400kV Mundka station.

2. No fault observed from PMU data. 3. Event was due to mal-operation of protection system.

DR/EL, Preliminary along with Detailed report from Delhi/ APCPL was to be received. DTL and UPPTCL were advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events.

e. Multiple Element tripping at 400/220kV Agra (PG) station on 13th Sep 2014 at 03:57hrs Event category: GI-2 Generation loss: Nil Loss of load: Nil Data Summary received to NRLDC:



Not Available

DR/ EL POWERGRID Not Received After 24hrs

UP Not Received


UP

Detailed Report POWERGRID Received After 24hrs

UP


Fault Clearance Time No Fault (Over Voltage tripping) As per PMU data




IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; POWERGRID, UP



UP



1. In the morning hours at 03:57hrs multiple element tripping occurred at 400kV Agra(PG) station due to over voltage protection operation. Name of the tripping elements are given below:

400kV Agra(PG)-Agra(UP) D/C (Double Ckt) Agra(PG)-Bhiwadi ckt-1 Agra(PG)-Bassi ckt

2. As per PMU data voltage touched to 440kV in Y-phase. There was rise in the voltage just before stage-1 pickup. Reason of the same couldn’t confirm.

3. NR SoE details of the tripping is given below:

Points for Discussion: 1. Multiple elements tripping on over voltage protection needs to be looked into. 2. Reason of rise in the voltage needs to be looked into. 3. Voltage Grading in over voltage protection needs to be looked into at Agra (PG) station.

As 400kV Agra (PG)-Agra (UP) D/C tripped. 4. Settings of over voltage protection of both end of 400kV Agra (PG)-Agra (UP) D/C is

different-different. It should be coordinated. Agra (UP) end settings are on lower side, it may be revised as per settings at PG end.

. DR/EL & Detailed Report from POWERGRID/ UP was awaited. POWERGRID and UPPTCL were advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events

f. Multiple Element tripping at 400/220kV Agra(PG) station on 14th Sep 2014 at 17:08hrs Event category: GI-2 Generation loss: Nil Loss of load: Nil Data Summary received to NRLDC:



Not Available


UP Not Received


UP Not Received

Detailed Report POWERGRID Not Received After 24hrs

UP Not Received


Fault Clearance Time No Fault (Over Voltage tripping) As per PMU data




IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3;

POWERGRID, UP

CEA Grid Standard 15.3; 43.4.D of CEA Technical Standard

for Construction of Electrical Plants and Electric Lines; CEA Grid Standard 15.4

UP


Based on above information description of the events is: 1. At 17:08hrs many of the lines from Agra (PG) tripped on over voltage protection

operation. There was ~8kV rise in the voltage in antecedent condition. It may be due to reactor switching or opening of line from one end. Name of the tripping elements are given below:

765kV Agra(PG)-Meerut ckt 400kV Agra(PG)-Sikar ckt1 400kV Agra(PG)-Agra(UP) D/C 400kV Agra(PG)-Bhiwadi ckt-1 400kV Agra(PG)-Bassi ckt

2. As per PMU data, there was rise in the voltage of ~8kV at 17:08:40.240hrs. After ~5 second, blue phase voltage dip by 100kV. However fault current was not showing in any DR.

3. 400kV Agra-Sikar ckt 1 tripped on distance protection operation. 4. 400kV Agra-Bassi line tripped only from Agra (PG) end. 5. 400kV Agra-Agra (UP) ckt1: Over voltage trip signal at 17:10:38.350hrs after ~58second

of O/V start signal. Line didn’t trip from Agra (UP) end. 6. 400kV Agra-Agra (UP) ckt2: Line didn’t trip from Agra (UP) end. 7. Probable Sequence of Event as per DR data:

8. NR SoE details of the tripping is given below:

Points for Discussion: 1. Voltage Grading at Agra (PG) end needs to be looked into. 2. Reason of tripping of 400kV Agra-Sikar line 1 on main2 distance protection needs to be

looked into. 3. Time Synchronization of DR/EL at Agra (PG) end needs to be checked & corrected. 4. Difference of ~6kV in the phase voltage of the DR needs to be looked into. 5. Synchronization of digital data needs to be looked into

DR, Preliminary report from POWERGRID had been received but detailed report & event logger data was awaited. DR/EL & Report from UP was awaited POWERGRID and UPPTCL were advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events.

g. Multiple element tripping at Jessore station on 21st Sep 2014 at 15:47hrs Event category: GI-1 Generation loss: Nil Loss of load: NIl Data Summary received to NRLDC:



DR/ EL

HP Not Received

BBMB Not Received

NHPC Not Received

Preliminary Report

HP Not Received

BBMB Not Received

NHPC Not Received

Detailed Report HP Not Received

BBMB Not Received

NHPC Not Received


Fault Clearance Time 80ms & 320ms As per PMU data

Phase of the Fault



IEGC 5.2.r & 5.9.6.c (VI); IEGC 4.6.3; HP, BBMB,

NHPC



HP, BBMB, NHPC


1. At 15:47hrs, CT blasted at 200kV Jassor S/S resulted into tripping of 220kV Baira-suil(NHPC)-Jassore(HP) & 220kV Jassor(HP)-Pong(BBMB).

2. First fault got cleared in ~80ms & other in ~320ms. 3. No SoE, related to tripping, reported at NRLDC.


1. Sequence of event & reason of multiple element tripping needs to be looked into. 2. Exact location & reason of fault to be ascertained. 3. Delayed Clearance of fault needs to be looked into. 4. Digital Data reporting to be looked into.

Preliminary Report, DR/EL & Detailed Report from HP, NHPC & BBMB had not been received. HPSEBL, NHPC and BBMB were advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events.

h. Multiple Element tripping at 400kV Gorakhpur(PG) station on 14th Oct 2014 at 09:20hrs Event category: GI-2 Generation loss: Nil Loss of load: Nil Data Summary received to NRLDC:


Availability of Digital Data (SCADA Data) Available



Detailed Report POWERGRID Not Received



Phase of the Fault Y‐B & R‐Y phase to phase fault As per PMU data



IEGC 5.2.r & 5.9.6.c (VI);

CEA Grid Standard 15.3;


CEA Grid Standard 3.1.e

POWERGRID 1. DR/EL, Preliminary report didn’t

provide within 24hrs 2. Fault clearance time more than 100ms


1. In antecedent condition there was heavy rainfall and storm in that area. 2. 400kV Gorakhpur(PG)-Muzaffarpur(PG) D/C tripped due to phase to phase fault. 3. As per DR/EL of 400kV Gorakhpur(PG) end 400kV Gorakhpur(PG)-Muzaffarpur ckt-1

tripped on Y-B phase to phase fault. 400kV Gorakhpur(PG)-Muzaffarpur ckt-2 tripped on R-Y phase to phase fault. As fault was phase to phase, it resulted into tripping of all 3-phase of the line in zone-1 timing. Both lines tripped from Muzaffarpur end on carrier received from Gorakhpur(PG) end.

4. 400kV Gorakhpur(PG)-Muzzafarpur ckt-1: a. fault current Ia= 2.32kA, Ib= 8.93kA, Ic=8.16kA 5. 400kV Gorakhpur(PG)-Muzzafarpur ckt-2: a. fault current Ia= 8.64kA, Ib= 12.78kA, Ic=2.93kA 6. Inferences on behalf of details available with NRLDC:

As per PMU data & DR/EL it seems that command has sent by the distance protection immediately but breaker may be opened with some time delay. As some voltage & current is showing in the DR.


1. Delayed Clearance of fault needs to be looked into. 2. Breaker opening time at Gorakhpur(PG) & Muzaffarpur(PG) end needs to be checked.

Preliminary report, DR/EL had been received from POWERGRID but detailed report was awaited. POWERGRID was advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events.

i. Tripping of Balia-Bhiwadi Bipole on 16th Oct 2014 at 02:00hrs Event category: GI-2 Generation loss: Nil Loss of load: NIl Data Summary received to NRLDC:



Not Available



Detailed Report POWERGRID Received








Based on above information description of the events is: 1. On 16 Oct 2014 early in the morning at 02:00hrs, bipole was running at minimal power

flow i.e.250MW. 2. 400kV Moga-Bhiwadi ckt-2 was opened for voltage regulation from other end that sent

DT signal at Bhiwadi end for intended opening of the line. However, one of the phases of the tie breaker got stuck which caused LBB protection of the tie breaker and both main breaker on that bay also opened. Consequently, AC filter-2 bank of HVDC got tripped. Other available filters could not be switched on because of overvoltage filter switching inhibit from pole control.

3. Hence the minimum filter requirement of HVDC could not be fulfilled causing HVDC bipole to trip from station control

4. SoE of Bipole tripping & opening of breaker of Moga & Bhiwadi end of 400kV Moga-Bhiwadi ckt2 was not captured.

5. DR/EL for 400kV Moga- Bhiwadi ckt2 & Event logger data of 400kV Bhiwadi AC station are required for further analysis.

Point for Discussion: Provision for Overvoltage filter switching inhibit be modified to bring in the AC filter in case of any AC filter tripping during minimum filter operation of Bipole needs to be looked into.

Preliminary Report, Event logger data of HVDC Bhiwad & detailed report had been received from POWERGRID. Event logger data of 400kV Bhiwadi AC station was awaited. POWERGRID was advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events.

j. Tripping of Unnao-Agra & Unnao-Panki Line on 25st Oct 2014 at 19:38hrs Event category: GI-2 Generation loss: Nil Loss of load: Nil Data Summary received to NRLDC:




Preliminary Report UP Not received After 24hrs

Detailed Report UP Not received



Phase of the fault Red‐phase As per PMU data



IEGC 5.2.r & 5.9.6.c (VI);CEA Grid Standard 15.3;

43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines;


UP 1. DR/EL, Preliminary report didn’t provide

within 24hrs


R-phase to ground fault (transient type) occurred in 400kV Unnao-Panki line. R-phase opened from both end due to DPT. Line auto reclosed from Unnao end but didn’t auto reclose from Panki end. Finally other phase breaker at Panki station tripped on PD(Pole Discrepancy).

At the same time 400kV Agra-Unnao line also tripped from Agra end. Single phase tripping occurred. Line didn’t auto reclose & finally all 3-phase tripped on PD(Pole Discrepancy).

Tripping of 400kV Agra-Unnao line from Agra end may be due to over reach of distance protection from Agra end.

Digital data of muradnagar station is not available at NR SoE Flag details is given below:


1. Auto recloser of 400kV Unnao-Panki line needs to be looked into. 2. Distance scheme for 400kV Agra-Unnao line needs to be checked. (It may be carrier

added POR scheme due to availability of FSC at Unnao end. 3. Auto recloser of 400kV Agra-Unnao line needs to be looked into. 4. Pole Discrepency protection setting at Agra & Panki to be looked into.

Flag details had been received from UP. Detailed report along with flag details was to be received. UPPTCL was advised to elaborate the incident and submit the detailed report covering “Points for Discussion” above and also inform about corrective actions already taken/being taken (within time line) to avoid such events.

28th Protection Sub-Committee meeting'of NRPC at Ludhiana on L9-L2'2OL4List of Participants

Sr No. lName Designation Utilitv Mobile Number Email lD lsienatu re

7 D.r-f),'n w.qh N &rrePncnr m 71toSt4qta3 Aqi a*9 @7"t"0, ,T,EhJ

2 <rGq" hqore- (;{r str sdv hrq.l-s(. 1g+r sen3 eff$db'60@tlr'"tt.(a 1."=n r'-\IaTf-)A >41t<e) aaaTfuiar l"f 'S9}*-D: 9s&"s::uzs+ Xada.vtr&n*qpaf 6rn m;

z M, s. Ha-le Meuogo^, fourtt(4( tt q6,soJTT7f i mshqdlsr @ltaJ,p FSu Sn tu 5r. e1.,;y<tt f au€Rtt ptg Ita/4JIoQs/ ; "t

lt ; f kt L6; g)"*,-0 e>, I'L6 A, K" s Ae,ap *t Wa-crq.fz- pra.4a\ 49ttoLoT sa"aftta-kOg^\ * .i<

Amrn /\7r7- 5f? Ltet, tJt Ptcv 4 bfo'lo'ltn arriin- azir@Iot-n* l'tTl..

Norr ^ A'u+rre C€ (rect $( ?r-t 4Q t{ztt"3i sn +.*QAQffnJ r* fr,LAl ,tt"" fr.i shns gf;(taq fYtaA

wTrcut"lt, r 1\tz)W lJ lal-n.ntLf4u La"q "Yt"'

1C Wvtutt, E*4r)Y144. M.rv15lr rElTw t

VPPTT.L-'r]r- D .'1 thtz)\38t \ ee]â*rvL2,qtwp;;

(. Cta4 E}

u2_

'?

I

77 Jahsx\ai;a/

Suh BI€lh& qQQvu l4s8o466olv

sn-hc@ wux!.,ttt<- {'bedz72 H"t*L Ct"an NytrTP"a Dru 4144{ssfr bI'grl*@i A "!*rt..t'

13 ?.r.. d*u ior\tr)SLDc\ \ -i--L tlrlsrscz ps+pvrr ve Qt'p e".C/*,. I

t4 UPaxlt{rr,.q- Mt rp{*t" )-rL ffifi 53366: '/"bYt't".w*+ , d,.#@ qiartL{" t tPlrl

H4n4&

15 8-L^Ya2ou /)€kt N 7724- ?(9a 113ov\, 6t U^>.--€ a pz.t ;- dl-

t6l4s'AK^ 7; ftCr^4 /VTPC etq ssasst rnah.(zi*@ntpe co,ta fl

77g'w go ril(affi.-l FTRLD L 1{6't4"9ry q"$ttquOf"to^ $4I

18 & t< I -Eazlop €t. JK PDD QQnw>7 kl*'d"t"PaEPa

t9 F " P' Rnlori h, kert' ,TH DCI L.TEF.A I eq rntLsvt vTjcnderpo,tb/A* '/. r,- (fr*/.

20 Lr S ChCI.u-l'.a"t nq''G"*| f&bc iNNrAlJb ,

31'71 aoo 3fz drneshch.at^k Xsr@ 4Yna.i.{^ Cbcn (d{""0

2t Vit"r- tfuv*rt' T,tt- i\e*5* G) NhPG Li-L lr7tgq gK$ --/^'nvK{ lq6Ll @' 7*";-u'6 \A*(

22g'?^9,*qn c"Jrl hJMPC 11tt&(3sg ,folb-0t"r"bcf4 vt*

23 K.. x-s \+eq'.rw4+V

?-FQrvr KRVUftL. 3qt hosz. r X e-s.t".v&,t-f-e O *.n* $qrc-e.44 (

24 A. n' T/vvpgl^\.

e'E'm fttrvrxu 1gt,to &V ry Ce nlPsAtvtut.,"o

25 l'?'h , 9/.n1*1 /y'-M) tUlNL )Vl)u 0bu, ue.^-p-t:[*V 6---26 Llaxi <.L KL..*"mc, S "IQ

NA IS^J

AROR.A9 +tr75g3z1 ha*'\lrgh'rns@"

rnbc r'!"(o,M \&s""4

27 M K. BLi vatAJ S.,iE N h?9N?Lt t- 4Ltr>1&BL7l r-rrU1;l'rô--Xi

3,^- gb-"f28

(a.tl^,+ ltÂurl/rrvJScievrt S^ca J(lcev I f'

KRtr.s-3rlNp czr- dq q,3J 16$ r$"crylr,lu@*fo)l'. tiltilr,tk

tlh * *r"t * t"li 4$ r't''r '* fl ''r:-r.t ' - i"

/

28th Protection Sub-Committee meeting of NRPC at Ludhiana on L9-L2-2OL4

{>1

I

List of ParticipantsSr No. Name Desienation Jtilitv Mobile Number Email lD iienaturd)

29 P;"-1, (t+, A E(fuT) HPS<SL 1\s(g8ttgl )- p** rAbn"{t "{}. L>'>t,

3C 12 lc r/u ^^ SE mpP h W{\f 93/tlBt3e &r*u**@l+ /---

31 ,As!,-t. G*t, lr t"?.*tPGcc 4zxl1er v> ducn'-lA \zl.

./att,f t.}t-

32 A K' c hao"leo d idannSe'Ct) warrlo*, q1v69u8l U^ U -UaXut"c.yk>g rntul com #"e33 KAanrr (tv{ -14 S'7fl'e- ( Tcu-t- i4l>;lnp; Mp!-ib €-

34'/a"rr-rlns;h; n+aM 9T fCL qull/t/s, a*:lfK" -4a/- I^/

35("-e. ( ur"i- As+] r* I sTrL 4Kqa*/tLrl .rr*ou-;y*:l{l I

36 P,r!;^l'-Qouv'w t;lf?y tt rct- $t t, tt- ttc,+1 fu),P, @Vo*u" a7, fr^37 E- ,R'-l.r I-l'.-- hq,^c alek ke-t** Tlqlit *tI t't fi ,l ru l,r'. a st E1 ualr,r, 1 " "4,

38

./

* L",;LV-+),,s"u Ct1leP P s<c_t_ 4Lqq tz 8., :-g

-qr il-tcq, gQ'/nJ..^ c' ; N.1

39 trf . k, (/r.iu'r r. fl, lpeo {)l'rc L- Flr,tttRzx'z- (G..L*'6' tts'ltf ,trI ,rto

40 c. oa. ^rt,-' Qt^Vt f-x ru I i-c. 0.- ", > I L4 LL*an:?3 D.t e -? eol (E flcvu aLa K

41 Fl.lo htr ANAND 9Fl p Lba 0S:7z.cprDu f;lilanant uaq(P*l gw*

42 Vrvrr. ,l-4/*^^ Nsd:rE/ k/"n -ra ? totzsqnj ,l)<< nhkh,/A-n^, ,-,u lt'-'

43 C.!,inohJ tst,v!#,+ 0Brng 9q6 g\q s t9 ilJ"f,'" a frLLwti; .ln

44 $onhrp bti. ^otg

Lt<r^

ne [ncP htvPruu Q3lssw &natrr?, XmA,&tinfrn Lq*';l.a

4!

I U

A, <-)-D^,1 latI

>u c-t2 fu Dr ot- Q,/*,+- n A 7-W) C-\,;^'> (A?-*" ()r.' 6

46t ) ,1,-nD'>-LS ttr f t7 o'- \teqti Lgoof

r.V*e-h*-:)l Q I's+or'1 lqa

47 r, A K. s-^-iL \^-' "f w?A Fsr ci a t\t\ \E{.; Ae -vn \- u *F F'u "-t-'Fl *

48 t?q-" t.v,).,,u Mdt s& ? g-rcL leuq z!4qb1 In>tr.t"t^Lo^tJ o 0"

49 Lil . I,,s, Srni lvdtW pe,r.r q b\(ttt?,e,I qawil'co' A Lf-ot-i z&, Aou^ ,t l,ll/,r

5C [:; ft r, i t..l 'i. {;t dr rsit\Ud"

,:' 9 ( r:.' t", t (A ' ,*l ., ,' 9.

51 t1.- ?-3- f\V!\'r.r- n4g NRP C

t/ {/ t-,/ , (_..

Se-o -"'trkr- Q *ir. \

52 S\.fM":1 T..\2^-.. a^ 9€ 61RP c-)o -

s3 s* Nal"%L, k'}" EE tl r

54 qL. PaI.,'\ KA AEB l1 t,l

55

Annex-II

Non- Availability/ Defective PLCC Link of STU Lines terminated at POWERGRID NR-2 substations

PLCC issues with J&K PDD

S.No Name of

Substation Name of Line Availability of PLCC Status

1 Wagoora

220 KV Zainakot-I Not Available

2 220 KV Zainakot-II Not Available

3

Kishenpur

220 kV Barn-I Not Available

4 220 kV Barn-II Not Available 5 220 kV Mirbazar Pending for

commissioning by PDD after LILO of 220 kV Kishenpur-pampore Ckts.

6 220 kV Ramban

PLCC issues with HVPNL 1 Panchkula 220 kV Raiwali-I Available/Not working As per HVPNL

PLCC has been made functional. There is need for testing

2 220 kV Raiwali-II Available/ Not working

3 Abdullapur 220 kV Railway-I Not Available Not Required

4 220 kV Railway-II Not Available Not Required

5 Kaithal 220 KV Cheeka-I Available / not working As per HVPNL PLCC has been made functional. There is need for testing

6 220 KV Cheeka-II Available / not working 7 220 KV Kaithal-I Available / not working

8 220 KV Kaithal-II Available / not working

9 Bahadurgarh

220 kV Noonamajra-I Panels available, Pending for commissioning

As per HVPNL PLCC has been made functional. There is need for testing

10 220 kV Noonamajra-II Panels available, Pending for commissioning

As per HVPNL PLCC has been made functional. There is need for testing

PLCC issues with PSTCL

01 Ludhiana 220kV Pakhowal Installed but not working As per PSTCL PLCC is working

02 Amritsar 220kV Verpal -I Not Installed As per PSTCL PLCC is working

03 220kV Khasa -II Not Installed As per PSTCL PLCC is working

04 220kV Verpal- II Installed but not working Working

05 220kV Khasa-I Installed but not working Working

Annexure-II

Status of Bus bar Protection for Northern Region Constituents

State/Constituent TRANSCO/GENCO

Total No. of Sub Stations/Switchyards (220 kV and above)

No. of substations/ switchyards where

Bus bar protection is functioning

Remarks Action Plan

Delhi DTL 37 34 At 220 kV s/stns namely Lodhi Road, Gopalpur and Kanjhawala it is being planned.

25 nos. new BBP is being procured. Under Approval Stage

Haryana HVPNL 61 30 On 21 it is defective, for 06 nos date is yet to be decided and for 05 nos. of sub‐stations it is not required.

.

20 nos would be commission progressively by 30.06.2016

HPGCL 03 03

Rajasthan RVPNL 95 23 81 nos. not provided. 06 nos under procurement RVUNL 05 05

Himachal Pradesh

HPSEB 07 03 For 1 sub‐station, it was defective and at remaining 03 sub‐station, installation of BBP was not feasible due to space constraint.

02 more would be installed by Nov. 2014 and 02 nos. in next one year

Punjab PSTCL 88 27 10 nos. commissioning in progress

PSPCL 03 03 J&K PDD 06 - Uttarakhand PTCUL 10 09

UJVNL - - BBMB BBMB 23 17 - -Not required at Dhulkote and Jagadhari as

there is no Bus Bar. - For Sangrur Process is initiated. Commission by March 2015 -For Barnala it is to be provided by PSTCL as agreed in PSC-PSTCL will commission it by 31.03.2015 - As per BBMB not required for Sangrur, Kurukshetra and Delhi as no. of feeders is less than five- But PSC decided that it need to be installed

Uttar Pradesh UPPTCL 82 10 21 nos. for 220 kV are under procurement stage. UVUNL 05 -

POWERGRID PGCIL 55 55 Central generating Stations

NTPC 11 11 NHPC 09 09 NPCIL 02 02

THDC 02 02 SJVNL 02 02

no. nrpc/opr/107/1/2014/ dated: 03.02.2015 fax message

Documents