northern regional electricity board

भारत सरकार िव�ुत मं�ालय

उ�र क्�ेय िव�ुत सिमित 18- ए, श.जेत �सह मागर ,कटवा�रया सराय,

नई �दलले -110016 Government of India,

Ministry of Power Northern Regional Power Committee

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

No. NRPC/OPR/107/1/2015/ Dated: 29.04.2016

Uफैकस संद्श / FAX MESSAGE �्षक From : Superintending Engineer (O), NRPC. सव्ा म� To : Members of Protection Sub-Committee (As per List) िवषय Sub : संरक् उ -सिमित क� 30वीं बैठक का कायरवव� Minutes of 30th Protection Sub-Committee Meeting. संरक् उ -सिमित क� 30वीं बैठक 21.09.2015 को उ.क्.िव.स., नई �दलले म� योिजत क� गई उउ बैठक का कायरवव� उ.क्.िव.स. क� वैब-साइट Uhttp://www.nrpc.gov.in U र उ लब् है The 30th meeting of Protection Sub-Committee was held on 21.09.2015 at NRPC, New Delhi. The minutes of the meeting are available on NRPC website at Uhttp://www.nrpc.gov.in U.

Sd/- (अजय तळेगावकर)/(Ajay Talegaonkar)

अधी�ण अ�भयंता (प्ाचा) एवं सयोजक सदसय, संर�ण उप स�म�त SE (operations) & Member Convener, Protection Sub-Committee

फोन- 26513265 फेक् Fax :26865206 ई मेल e- mail: [email protected] वेब्ाईट Website : www.nrpc.gov.in

http://www.nrpc.gov.in/�


List of Members of Protection Sub-Committee

1. Director (P&C)/BBMB, Chandigarh, Fax-0172-2652054 2. General Manager (SLDC), DTL, 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. SE(T&C), PTCUL, Fax No 0135-2451826 10. Chief Engineer (SLDC), UPPTCL, Fax- 0522-2287880, 2288736 11. SE (Tech). HPGCL, Fax-0172-5022436,SE(O&M-VI),Panipat Fax:0180-2566768. 12. Chief Engineer (Transmission), HPSEB, Hamirpur, Fax-01972-223435 13. SE (PR& ALDC), HPSEB Ltd., Fax-0177-2837143 14. Chief Engineer (Comml. & Survey Wing) PDD, Jammu, Fax-0191-2474233 15. Chief Engineer (SLDC), PSTCL, Fax – 0175-2365340 16. Chief Engineer (P&M), PSTCL, Ludhiana, Fax-0161-2741280, 2451491 17. CE (M&P), RRVPNL, Jaipur, Fax-0141-2291891 18. SE (Electrical), RRVUNL, Suratgarh, (Rajasthan), Fax-01509-245299 19. Chief Engineer (LD); RRVPNL, SE (SO&LD) – Fax- 0141-2740920 20. Superintending Engineer (T&C), UPPCL, Meerut (U.P.), Fax-0121-2666062 21. Chief Engineer, (L-2), UPRVUNL Lucknow, Fax-0522-2287822, 2287880 22. DGM (T&C), PTCUL, Dehradun, Fax-0135-2760331 23. Chief Engineer (O&M), NHPC, Faridabad, Fax-0129-2272413 24. NPCIL

(i) Maintenance Superintendent, NAPS, Narora, Fax- 05734-222167 (ii) Maintenance Superintendent, RAPS, Rawatbhata, Fax- 01475-242060

25. GM (O&M) NR – I, PGCIL, New Delhi, Fax-011-26601079 26. GM (O&M), NR-II, PGCIL, Jammu, Fax-01951-237186 27. Chief Manager (TS), N.R.L.D.C, New Delhi, Fax- 011-26852747 28. GM(OS-NR), NTPC, Lucknow, Fax No. 0522-2305848 29. GM (OS) NTPC Ltd., Noida, Fax-0120-2410082, 2410068 30. DGM (Maintenance), SJVNL, New Shimla, Fax- 0177-2673283 31. DGM (O&M), THDC India Ltd., Tehri Garhwal, Fax No 01376-236305 32. Director (GM division), CEA, New Delhi, Fax-011-26109750 33. General Manager, APCLP, Fax No. 01251-266326 34. Director JPPVL, Fax- 0120-4516201/4609464/4609496 35. Assistant Vice President, BRPL, Fax- 39996055, 39999765 36. GM (Production), Jhajjar Power Ltd., Fax- 01251-270155 37. GM(P&M), APL, Fax No. 07925557176

The Sub-committee confirmed the minutes of 29th meeting of Protection Sub-committee, held on 09.02.2015 at NRPC Secretariat, New Delhi issued vide letter no. NRPC/OPR/107/01/2014 dated 14.08.2015. The Minutes are available on NRPC’s website at

Summary record of discussions held in the 30th Protection Sub-Committee meeting held on 21.09.2015 at 10:30 hrs. at NRPC Secretariat, New Delhi

The list of participants is enclosed at Annexure-I.

A.1 Confirmation of minutes of 29th meeting of protection sub-committee

http://www.nrpc.gov.in. A.2 Follow up action on outstanding issues from previous meetings

A.2.1 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 disabled due to faulty PLCC channels (at PSTCL and HVPNL ends). Status as updated in 30th PSC is as under: Sr.No

Transmission Line (220 KV)

Other end

Status as updated in 30th PSC

1 Jamalpur-Dhandari-I&II

PSTCL PLCC has been tested and found functional for 220 kV Jamalpur-Dhandari-I. For ckt-II both the ends are ready and end to end testing has also been carried out. However, PSTCL stated that work to be done by BBMB related to DTPCC is still pending.

2 Jalandhar-Butari

PSTCL PLCC has been tested and is functional.

3 Jalandhar-Jamsher-I&II

PSTCL PLCC has been tested and is functional.

4 Barnala–Lehra-Mohabbat

PSPCL PSTCL stated that ownership of this line belongs to BBMB and so the equipments at both ends. He further claimed that BBMB has to initiate the action to complete the PLCC at both ends. Howerver, BBMB


In thi

In this PSC meeting, SE (O), NRPC expressed concern for the delayed/non-completion of PLCC work for the last several PSC meetings. It was requested to HVPNL, PSTCL and BBMB to resolve all the pending issues related to PLCC as highlighted in 30th PSC meeting.

A.2.2 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 30th PSC meeting is enclosed as Annex-II. In the 29th PSC meeting, it was decided that even if PLCC is non-functional, auto-reclosure should be kept operational. Further, 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.2.3 PLCC and protection issues related to DTL

The updated status of the PLCC/ protection issues pertaining to DTL as intimated in 30th PSC meeting is as follows: Station/Line Issue Status as

updated by DTL in 30th PSC meeting

Ballabhgarh S/s 400kV Ballabhgarh-Bamnauli-I

REL521 – Both Main-1 & Main-2 relay were of same make/algorithm

It was clarified that it is not a regulatory requirement to have Main-I and Main-II of different

400kV Ballabhgarh-Bamnauli-II

countered his view. SE(O) requested both the parties to resove the issue bilaterally.

5 Samaypur-Badshahpur HVPNL In the 30th PSC meeting, HVPNL informed that it would be functional by 31.03.2016.

6 Samaypur-Palwal-I&II

HVPNL In the 30th PSC meeting, HVPNL informed that it would be functional by 31.03.2016.

7 Samaypur-Palli-I&II

HVPNL It has been tested and found ok.

8 Bhiwani-Bapora-I&II

HVPNL Radial feeders. Not required.

make/algorithm. This is only recommendatory in nature. DTL had stated that the issue has been resolved.

Mandola S/s 220kV Mandola - Narela-I

QUADRAMHO – Static relay needs to be retrofitted with numerical relay

Completed

220kV Mandola - Narela-II In this PSC meeting, representative of DTL stated that all the issues related to DTL as mentioned above have been resolved.

A.2.4 Auto Re-closure issues related to NTPC- Unchahar The updated status is as follows:

Station/Line Issue Status as updated by NTPC

Rai Bareilly S/s 220kV Rai Bareilly-Unchahar-I

Auto re-closure scheme was not functional at Unchahar end.

Scheme has been made functional. 220kV Rai Bareilly-

Unchahar-II 220kV Rai Bareilly-Unchahar-III Kanpur S/s 220kV Kanpur-Unchahar-I Auto re-closure scheme was not

functional at Unchahar end. Would be set right by Dec.,2015 along with the installation of numerical relays.

220kV Kanpur-Unchahar-II 220kV Kanpur-Unchahar-III 220kV Kanpur-Unchahar-IV

A.2.5 PLCC and Auto Re-closure issues related to UPPTCL

In 28th PSC meeting, POWERGRID had informed 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.

The status as updated in the 30th PSC meeting is as below:

S. No. Name of Line Details of PLCC

Details of Auto Re-closure

Status submitted

during the 30th meeting of

PSC 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. In earlier meeting, it was informed that Wave Trap was being procured and scheme would be functional by March, 2015. In this meeting, no update was given

A/R is not functional

Wave trap not arrived at s/s. Expected by October, 2015. SE (O), NRPC requested to expedited action for the same as the matter is being monitored by CERC. Further, POWERGRID also expressed concern for non-fuctioning of the A/R.

2. 220kV Allahabad-Rewa Road-II


B. Kanpur S/s 1. 220kV Kanpur-

Mainpuri PLCC panels are not available


The representatives of UP presented in the meeting could not provide the updated status.

2. 220kV Kanpur-Naubasta


3. 220kV Kanpur-Panki-I A/R is not functional

4. 220kV Kanpur-Panki-II


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


3. 220kV Mainpuri-Mainpuri(UP)-I


4. 220kV Mainpuri-Ferozabad


D. 400/220kV Lucknow S/s

1. 220kV Lucknow-Sitapur

In earlier meeting, it was informed that PLCC available but tele-protection and auto reclosing features were not available in the relay.


It is being LILO at Bakshi Ka Talab. PLCC panel is ready for commissioning and will be commissioned in the next shut down of the s/s.

2. 220kV Lucknow-Chinhat

In earlier meeting, it was informed that PLCC and A/R was functional and testing was required.


It is functional as stated by UPPTCL. POWERGRID would confirm the same within one month.

D. Gorakhpur S/s 1. 220kV Gorakhpur-

Barhua PLCC is not functional


PLCC panel is expected by Nov.’15. 2. 220kV Gorakhpur-

Basti PLCC panels are not available


E. Merrut S/s 1. 220kV Merrut-

Modipuram-I A/R is not

functional Some PLCC cards are defective. POWERGRID would replace the faulty cards.

2. 220kV Merrut-Nara In earlier meeting, it was informed that PLCC and A/R was functional. Testing was required.


It is functional as claimed by UPPTCL. POWERGRID would confirm the same within one month.

3. 220kV Merrut-Modipuram-II


Relay Changed. PLCC panel to be replaced by POWERGRID.

4. 220kV Merrut-Simbhawali

In earlier meeting, it was informed that PLCC and A/R was functional. Testing was required.


Issue is expected to be resolved within a week.

5. 220kV Merrut-Shatabadi Nagar


Scheme is functional.

6. 220kV Merrut-Gajraula

PLCC is not functional


New PLCC panel Main I&II Expected by Oct.’15.

7. 220kV Merrut-Nehtaur A/R is not functional

F. Rai Bareilly S/s 1. 220kV Rai Bareilly-

Chinhat In earlier meeting, it was informed that PLCC and A/R was functional. Testing was required.


It has been tested and found to be functional.

2. 220kV Rai Bareilly-Sarojini Nagar

In earlier meeting, it was informed that Protection panels had been arranged for 220kV Rai Bareilly-Sarojininagar line, which was being installed.


It would be functional by Oct.,’15.

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

A.2.6 Islanding scheme for Rajasthan, Haryana and Punjab

A.2.6.1 SE (O), NRPC stated that in the 29th PSC meeting, it was decided that RVPNL would operationalize the existing islanding scheme meant for RAPP-A and RAPP-B excluding Mahi HPS till the results of dynamic simulation studies are received from CPRI. If simulation reveals that islanding would function well with inclusion of Mahi HEP, RVPNL can go ahead with their proposal of including Mahi HEP in the scheme.

In this meeting, representative of RVPNL stated that existing islanding scheme meant for RAPP-A and RAPP-B will change entirely if Mahi HPS is excluded from the scheme. Also, result of dynamic simulation studies has not yet been received from CPRI. SE(O), NRPC requested RVPNL to implement the scheme provisionally & necessary actions for procurement of relays etc. may be initiated with completion target of one year. RRVPNL agreed for the same.

A.2.6.2 SE (O), NRPC stated that islanding scheme for the state of Haryana 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. A request was made to HVPNL to discuss the scheme with NTPC as their Faridabad gas station was part of the proposed islanding scheme. HVPNL had agreed to

review the scheme. In the 27th PSC meeting, certain suggestions were made for proposed islanding scheme. In 28th PSC meeting, HVPNL had informed that changes suggested by PSC were under consideration.

In this PSC meeting, HVPNL again stated that changes suggested by PSC are under consideration and they will submit the concrete result by the next PSC meeting.

A.2.6.3 A meeting was held on 27th November, 2014 at NRPC Secretariat to review the islanding schemes for Punjab. In this meeting, it was decided that PSTCL would implement the scheme envisaged for Lehra Mohhabat TPS and Bhatinda TPS at first instance. Thereafter, based on the experience of such scheme, the islanding scheme meant for Ropar TPS would be implemented. PSTCL had 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. In the last PSC meeting, PSTCL had informed that report was awaited from CPRI. The report was expected by February 2015. It was expected that the scheme would get implemented by September 2015.

In this PSC meeting, PSTCL informed that CPRI has submitted the dynamic study for islanding scheme for Bhantida TPS and PSTCL is under process of implementing the scheme. Procurement process is underway and the scheme will get implemented by 30.11.2015. PSTCL was requested to share the approved scheme with NRPC Sectt. and NRLDC. PSTCL agreed for the same.

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 abstract in regard to expected completion time of rectification of protection related deficiencies as informed by utilities is under

S.No. Utility No. of sub-stations covered under BPA

Expected Completion

Remarks

1 UPPTCL 21 March, 2016 220 kV Chinhat & 400 kV Agra completed Rest by March, 2016

2 UPRVUNL 4 April, 2016 except PLCC at Obra’ A’ & Harduaganj-Feb., 2016

Obra’B’ – completed. Anpara – Completed. Obra’A’ – June, 2016 (including rectification of Time synchronization & BBP, PLCC (to be installed by UPPTCL). Harduaganj– BBP & PLCC work shall be expected to be completed by Feb.2016.

3 RRVPNL 8 November, 2016 Rectification of seven sub-stns completed. 400 kV Ratangarh S/s is expected to be completed by November, 2016. In 36th NRPC meeting Rajasthan agreed to complete it by March, 2016.

4 RRVUNL 2 Suratgarh & Kota– Completed (September, 2015).

Suratgarh & Kota – Completed.

5 HVPNL 1 Completed (20.09.2013)

Completed.

6 HPGCL 3 Completed (July, 2015)

(i) PTPS-I & PTPS-II (Unit 5, 6, 7 and 8) completed. RGTPP, Khedar-No deficiency observed during BPA.

7 PSTCL 3 Completed Rectification work of three sub-stns. have been Completed. Further, the defects at 220 kV Sarna-Udhampur line observed, pertains to PDD, J&K which is not yet completed by PDD, J&K. PDD, J&K needs to rectify the defects of PLCC system of 220 kV Sarna-Udhampur line.

8 PSPCL 1 Completed (Ropar TPS)

The expected completion as per report is November, 2015.

9 DTL 1 June, 2015 Completed on 14.06.2015 10 HPSEB Ltd. 1 March, 2016 Out of 12 deficiencies observed, 8

items stand already rectified. The rectification of defects of remaining 4 No. items will be completed by the end of March 2016.

11 PTCUL 2 June, 2016 Rishikesh-Completed. 132 kV Kashipur S/s. –June, 2016

12 UJVNL 1 30-06-2016 Breaker for 220 kV Khodri-I &II needs to be replaced.

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

As informed during 33rd NRPC meeting that deficiencies where procurement was not involved had been rectified and other works where procurement is involved are yet to be taken up. PDD J&K informed that they have submitted the proposal for PSDF funding and deficiencies will be rectified when fund will be disbursed from PSDF.

14 BBMB 7 Completed Completed 15 POWERGR

ID 46 Completed by

POWERGRID (16.10.2014) (except restoration of PLCC system at remote end connected with other utilities).

POWERGRID informed that PLCC panel has been planned with LILO at Varanasi. Will be replaced by 31.01.2016

16 NTPC 10 June, 2016 Completed except Rihand: June’16.& Unchahar: March,’16.

17 NHPC 8 Chamera-II – March, 2016

Salal, Uri-I, Dhauliganga, Chamera-III, Tanakpur, Dulhasti, Chamera-I –Completed. Chamera-II –March, 2016

18 SJVNL 1 Completed

19 THDC 1 Completed. 20 NPCIL 1 Completed

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.

The summarised status of TPPA as available with NRPC is enclosed as Annex-III. Utilties were requested to update the status and submit the time bound action plan for rectifications of deficiencies. In this meeting representative of NHPC informed about the frequent trippings of POWERGRID’s 220 kV Sarna-Heeranagar line. POWERGRID stated that this is happening due to lack of protective equipments at J & K PDD end that has to be installed by PDD. SE (O), NRPC suggested to form a group to identify the causes for this tripping and also the issues that has to be taken up with J & K PDD. Accordingly, group comprising of Shri. Sushil, POWERGRID and Shri I P Ranjan, NHPC was constituted. The Group shall submit the joint report to PSC within a month highlighting the seriousness of the issues including trippings occurred during the last six months, financial loss incurred due to the same etc. Further, POWERGRID stated that situation is expected to improve after the LILO of Sarna-Heeranagar line at Samba.

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 was enclosed as Annex-IV. Utilities were requested to expedite the implementation of Bus Bar Protection schemes and submit the information. Utilities were requested to expedite the implementation of Bus Bar Protection and submit the information to NRPC Sectt.

A.6 Setting of out of step protection RVPNL had informed that one of the relay on the Chhabra-Bhilwara line at Bhilwara end had mal operated. The relay had 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. In 28th PSC meeting it was decided that RVPNL will share the setting and trip file with POWERGRID. Representative of RVPNL informed that he had shared the setting and trip file with POWERGRID, which was under study by POWERGRID. POWERGRID was requested to study the same and give their opinion in the next PSC meeting. In this PSC meeting, consensus could not be arrived on this issue. PSC decided to drop this agenda point.

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 had 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 had requested members of NRPC to initiate action for implementation of recommendations of the Task Force. Some of the issues arising out of recommendations of the Task Force were as under:

A.7.1 Database of protection settings

SE(O), NRPC informed that 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. 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 STUs so as to bring the uniformity as far as possible. In 28th PSC meeting, RVPNL had submitted the information about relay setting in a Excel format, which was forward to POWERGRID for preparing the database format. In the 29th PSC meeting, POWERGRID suggested a format which was acceptable to all the constitutes. Further certain changes were suggested in the format after which POWERGRID was supposed to forward the formats to NRPC Sectt. for circulation to all the constitutens for preparing a database of protection relays.

http://www.nrpc.gov.in/reports/other/taskforce_analysis.pdf�

In this PSC meeting, representative of POWERGRID presented the format to PSC which was agreeable to the members. SE(O), NRPC suggested to begin with the data may be uploaded in pdf for viewing purpose only and also for the system of 400 kV and above. It was also stated that if any change is taking place at any location, it shall be updated by uploading the new file. This format shall be available in excel file at NRPC website that will be available as template for filling the data.

A.7.2 Zone-III settings

During the interaction (10-14 August 2015) with the consultants appointed by the CTU to review the status of implementation of Enquiry Committee recommendations, while POWERGRID had confirmed that they have reviewed the Zone-III settings in line with recommendations of the Task Force, generating companies like NTPC and NHPC had informed that POWERGRID had not advised them about revision in settings, if any, in their switchyard. Considering that the issue is directly linked with the safety and security of the grid, POWERGRID vide letter no.-NRPC/OPR/105/11/2015/1051-55 dated 02.09.2015 was requested to coordinate with entities at other end of their transmission lines for Zone-III settings (copy was enclosed as Annex-V of the agenda). In the aforesaid letter, POWERGRID was also requested to confirm about implementation of all the recommendations of the Task Force to the NRPC Sectt.

In this PSC meeting, representative of POWERGRID agreed to provide all the infeed data of their lines to the concerned generating companies so as to review the Zone-III settings in line with recommendations of the Task Force. The generating companies were requested to carry out the calculations for the revised settings for their switchyard and get it reviewed/reconciled by POWERGRID. However, on the issue of the latter, representative of POWERGRID stated that they will take up this matter with their higher management and revert back to NRPC Sectt.

Further, POWERGRID vide letter no. NR-1/NRPC/Zone-3/6824 dated 01.10.2015 reported that POWERGRID has reviewed Zone-3 settings of all feeders emanating from its stations in 2012 after twin grid failure of July, 2012. As per recommendation of “Sub Committee on Relay/Protection under Task force for Power System Analysis under Contigencies”, POWERGRID has reviewed and implemented the relay setting of all lines emanating from its stations. For setting of Back-up zones & Back-up protection of Line & Transformer,POWERGRID has obtained the data from remote and stations(i.e. shortest/longest line emanating from remote, no. of transformers along with % impedance etc.) for setting coordination. Reviewing/Modification of Relay settings is not one time exercise and needs regular check whenever any new transmission element is commissioned.It is to mention that guidelines are already available as per above referred Task Force Recommendations in Public domain.The review of Zone-III sttings of lines emanating from POWERGRID sub-stations and terminating in to the bays owned by other utilities,such utilities may be advised to implement the zone-III sttings as per above referred Task Force Recommendations at their end. POWERGRID may provide necessary input parameters/fault data for settings calculations by such utilities as per their request.

A.7.3 Protection relay setting guidelines for 765 kV, 400 kV and 220 kV transmission

lines A sub-committee constituted by above mentioned Task Force for examining philosophy of relay and protection coordination had also given the Protection relay setting guidelines for 765 kV, 400 kV and 220 kV transmission lines. As decided in 27th PSC meeting, to review the uniform philosophy agreed by NRPC in the light of report of the subcommittee constituted by task force, a group was constituted. In this PSC meeting, it was informed that the metting of the said group had already been taken place and report for the same shall be submitted soon.

A.8 Fresh nominations for Protection sub-committee

Nominations for PSC were received long back and since then many changes would have taken place in the organizational structure of the member utilities. Therefore Constituents were requested to submit fresh nominations to the Protection sub-committee (PSC). It may be noted that as per the Northern Regional Power Committee (Conduct of Business) Rules, 2006 (Sl no. 21.2.1)- “The nominated representative shall be at the level of Chief Engineers or equivalent level and concerns with power system protection / testing in the region.”. All the constituents were requested to submit the nominations at the earliest.

A.9 Protection Audit of BBMB S/s and POWER Houses by CPRI (Agenda by

BBMB) Representative of BBMB sated that during Protection Audit of all the BBMB sub-

stations and Power Houses /Switchyards by CPRI certain recommendations of

CPRI need to be addressed at common platform of NRPC and all the State Utilities

, hence the same have been incorporated as point(s) of are as under :

1. GPS Stamping

2.

: It has been observed that numerical relays of some of the inter-

state Transmission lines are not time stamped as per GPS. The matter needs to

be addressed and uniform instructions to all State Utilities need to be imparted.

End to end Testing of Transmission lines: As per CPRI recommendations in

Protection audit, end to end testing of Transmission lines are to be carried out

periodically. Uniform instructions regarding the procedure (such as with time

stamping), periodicity and priority (or all the 220kV400 kV Transmission lines)

may be imparted to all the state Utilities.

3. On-line monitoring of 400 kV Transmission line Breakers

4.

: CPRI has

recommended the On-line monitoring of 400 kV Transmission line Breakers in its

Protection Audit report. At present prevailing maintenance and diagnostic test

protocol is being followed meticulously hence it may be discussed on a common

platform of state utilities that matter may be taken up at discretion of department

or mandated to all the state power utilities.

Relay Test procedure

5.

: CPRI has recommended in its report that periodicity of

testing numerical Relays should be 4 years and that for electromechanical/static

relays should be 1 year whereas at present it is 2 years for numerical and 1

year for electromechanical/static relays ,hence it may be discussed on a

common platform of state utilities that matter may be taken up at discretion of

department or mandated to all the state power utilities in respect of uniform

procedure and test periodicity of thenumerical as well as Elecromechanical/static

Relays .

Uniform Policy for CT monitoring

6.

: CPRI in its protection audit report has

recommended that keeping in view the very old CTs in sub-stations, the same

may be tested in terms of the integrity i.e. accuracy limit factor, saturation and

burden parameter for which two methods have been suggested, one is to

rotationally changing CTs and testing thereof and other is to get them tested

from CPRI Mobile Instrument transformer test facility for CTs at respective sub-

station. It is felt that matter need to be deliberated on commom front of all the

power state utilities.

Relay setting Validation:

In this PSC meeting, utilities took note of the above recommendations.

A.10 Providing Bus Bar Protection in mesh arrangement (Agenda by BBMB)

CPRI in its protection audit report has recommended

that for Relay settings of critical transmission lines and Corridors, the Relay

settings calulations be validated simulataneously on Real time Digital simulator

(RTDS). It is felt that matter is required to be discussed at commom front of all

the power state utilities and based upon the inputs and experience of all the

Utilities, necessary action is required to be taken accordingly.

Representative of BBMB stated that as discussed in various Protection sub

committee(s) of NRPC, Bus Bar arrangement is to be provided in all sub-

stations irrespective of no. of bays. In this regard it is intimated that 2 no. sub-

stations of BBMB ( 220 kV sub-station Dhulkote & 220 kV Sub-station Jagadhari

) have mesh type Bus arrangement and this office is of the view that since Bus

Bar protection in not required for these sub-stations since the protections

provided for individual circuits connected to the bus include the bus (and also

the circuit breakers) as well within their zone of protection.Further the issue was

also elaborated during Conference on “ Advances & Innovations in Sub-

stations “ in CBIP Conference Hall, New Delhi (by Sh. N.S. Sodha, Former

executive Director, Load Dispatch and Communication , PGCIL during the

conference from 25-26 June -2105 in his presentation on EHV sub-stations in

Indian Power system –The Journey Continues ) that No Bus Bar Protection is

required to be provided in Ring Bus Scheme.

PSC was of the view that the bus bar protection may not be required in the aforesaid sub-stations as the protections provided for individual circuits connected to the bus include the bus (and also the circuit breakers) as well within their zone of protection.

A.11 Failure of FSCs installed at Unnao and Meerut Substation (Agenda by NRLDC)

Representative of NRLDC reported that the FSC installed at Unnao- Bareilly(UP) Ckt-1 at Unnao failed on 19/04/2015. On 16/07/2015, FSC installed at Meerut –Koteshwar Circuit-2 also failed. Both the FSCs are still out of service. Failure of two FSCs in a gap of three months needs to be analyzed to avoid recurrence of such events. As per Para 27 of the CEA Grid Standards, the entity is required to analyze such equipment failures to avoid recurrence and such reports may be submitted to the Regional Power Committee. In this PSC meeting, representative of POWERGRID agreed to submit the detailed report in the next PSC meeting by analyzing the causes of failure of the equipments along with the action taken on the same so as to avoid such recurrence in future. Further, on the issue of evacuation of power (approx. 1500 MW) in such condition, SE(O), NRPC requested NRLDC to write a letter to THDC for the SPS for backing down of generation. NRLDC agreed for the same.

A.12 Standardization of Disturbance Records and Event Logger Inputs (Agenda by

NRLDC)

Representative of NRLDC stated that Disturbance Recorders on Transmission elements are necessary for post disturbance analysis, and identification & rectification of any protection mal-operation. As per CBIP’s manual on Protection of

Generators, GT, Transformers and Networks, it is recommended to have minimum 8(eight) analog signals and 16(sixteen) binary signals per bay or circuit. Also, it should have a minimum of 5 sec of total recording time, minimum pre-fault recording time of 100 msec and minimum post-fault recording time of 1000 msec. A list of typical signals (Analog / Binary) that are required to facilitate post-event analysis, may be finalized after discussion among constituents of NR. It is also felt necessary to finalize the nomenclature being used for Analog / Binary channels in order to enable easy comprehension Event Logger prove to be instrumental in analyzing the tripping incidents, particularly those of multiple tripping. However it is felt that the list of signals to be wired for event logger needs to be standardized to ensure availability of all necessary signals and remove any un-necessary inputs. It is understood that the exact list of inputs shall vary with the type of bus scheme, type of bay (line, transformer and reactor). Thus an indicative list of inputs to be configured for a 400kV substation ( 1 line bay, 1 transformer bay, 1 reactor bay) needs to be finalized after discussion among the constituents of NR. In this PSC meeting, SE(O) requested POWERGRID to submit a format in the next PSC meeting which shall cover the aforesaid issues. POWERGRID agreed for the smae.

B.1 Tripping events

A. Multiple Element tripping at 765kV Anta Station on 3rd Feb 2015 at 10:52hrs:

Event category: GI-2 Generation loss:600MW (Planned SPS operation) Loss of load: Nil

Description

Data Summary received at NRLDC: Fault Info Remarks

Fault Clearance Time 80ms As per PMU data

Phase of the fault R-Y phase to phase to ground fault

As per PMU data

Description Utilities

Present Status

Remarks

Availability of Digital Data (SCADA Data) Available

Time Synchronization is not okay

DR/ EL Rajasthan Not received

Printout of DR/EL not available

APL Not received

Preliminary Report Rajasthan Not received After 24hrs

APL Not received

Detailed Report Rajasthan Received

Description Clauses Utility Remarks

Violation of Clauses

1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 3. CEA (Technical standards for connectivity to the Grid) Regulation, 2007-6. 4.d

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

IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; 43.4.A & 43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines; CEA Grid standard 2010 -3.e CEA Transmission Planning Criteria

Rajasthan

1. DR/EL, Preliminary report didn’t provide within 24hrs, 2. Availability of DR/EL at station 3. Healthiness of Bus Bar Protection

1. 765/400kV Anta station has connectivity with Phagi D/C at 765 level, three 765/400kV 1500MVA ICTs, at 400kV level D/C Kawai. At anta station one bus was under charged condition, other bus is under commissioning.

Based on above information description of the events is:

2. At 10:52hrs of 3rd Feb 2015, during charging of newly commissioned 400kV Anta-Kawai-2, line disk of 400kV Chabra-2 got punctured & Bus bar protection operated resulting in tripping of 765/400kV ICT-1,2 & 3 at 765kV Anta(RVPN), 400kV Anta-Kawai ckt1. Unit #2 at Kawai(Adani) TPS also tripped on SPS.

3. From PMU Plots it is inferred that fault got cleared in time(~80ms) and fault was in R & Y Phase as voltage dip is highest in those phases.

4. Due to the tripping of units frequency fell by 0.07 Hz in the event. 5. From the frequency plot it is observed that frequency observed oscillations after the tripping of

Unit-II & 400 kV Anta-Kawai-I, this may have happened because of hunting of Unit-I caused by change of load. Total generation of Unit-I was getting evacuated via 400 kV Kawai-Chhabra.

6. The oscillations were also observed in power flow of 400 kV Agra-Bassi 7. PMU plots are given below:

8. SCADA Data plot:

9. The generation of Kawai plant(two units of 660 MW each) was 1200 MW at the time of incident. 10. The loading of 400 kV Anta-Kawai-I was approx. 940 MW before the tripping and rest generation

of Kawai was getting evacuated via 400 kV Kawai-Chhabra.

11. Zone-2 started in 400kV Kawai-Anta ckt-2 from Kawai end. Line didn’t open as fault get clear from remote end. Kawai unit tripped on account SPS operation due to power flow in the line less than 10MW.

12. NR SoE:

13. Extract of Disturbance report from Rajasthan:

Member of Rajasthan informed that in antecedent condition one bus was operational and other bus didn’t commissioned. Bus Bar Protection was of ABB make REB-500 relay. Close in fault occurred on newly commissioning 400kV Anta-Chhabra ckt-2. Location of fault was in the bay of Anta sub-station. At the same time ABB make REB-500 bus bar protection relay mal-operated. After this tripping, tripping on bus bar protection has disconnected and put under observation. After the incident many times fault observed into the system and relay sense the fault but didn’t operate. Issue has been raised to ABBIndia, they didn’t find any problem in the algorithm of the relay.

1. While charging 400kV ANTA-KAWAI circuit #1 from ANTA end for the first time the suspension string of 400kV CHHABRA line Bay failed & that caused a Line fault within the diameter of ANTA-KAWAI circuit 1.As the Line Breaker of KAWAI Line was not available it was being charged through tie breaker & Bus breaker for CHHABRA # 2 Line as both the lines are in same diameter at ANTA. The Bus bar protection (Main 1) on 400 kV systems at ANTA tripped supply on 400 kV side of Grid substation wrongly even when the fault was not in the jurisdiction of that protection system. The fault may be was within the yard but on the Line side of CHHABRA bay. M/S ABB supplier of the REB 500 relay at ANTA has still not answered on the issue & the Relay is in disabled state.

Protection Committee Conclusion:

2. All the elements connected to 400kV Anta station tripped due to only one bus is under operation in antecedent condition.

3. Fault clearance time was ~80ms. 4. Multiple element tripping due to wrong operation of bus bar protection. 5. DR/EL of the tripping didn’t provide by the RVPNL. 6. Digital data didn’t available from 400kV Kawai & Anta station. 7. Preliminary Report has been received from Rajasthan. DR/EL & report from Kawai also received.

1. Healthiness of ABB make REB-500 Bus Bar Protection to be ensured. (Action: Rajasthan; Time Frame: 15days)

Protection Committee Recommendations:

2. Availability of DR/EL of Anta station & digital data at 764/400kV Anta station to be ensured. (Action:Rajasthan; Time Frame: 1 months)

3. Availability of digital data of 400kV Kawai station to be ensured. (Action: APL-Kawai; Time Frame: 1 months)

B. Multiple Element tripping at 400/220kV Daultabad station on 14th Feb 2015 at 17:15hrs Event category: GD-1 Generation loss:Nil Loss of load: 120MW

Description



Phase of the fault Y-phase to ground fault

As per PMU data


Present Status

Remarks



DR/ EL Haryana Not received Printout of DR/EL not available

Preliminary Report Haryana Not received After 24hrs

Detailed Report Haryana 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

Haryana

1. DR/EL, Preliminary report didn’t provide within 24hrs, 2. Availability of DR/EL at station 3. Delayed clearance of

Electric Lines; CEA Grid standard 2010 -3.e CEA Transmission Planning Criteria

Fault

1. Connectivity Diagram: Based on above information description of the events is:

2. In antecedent condition bus bar protection at 220kV Daultabad station was under outage

due to replacement work of the same. ABB make static bus bar was being replaced with ER make numerical relay.

3. R-phase CT of Daultabad-Nunamajra ckt1busted. It resulted into falling of jack bus on main bus. At the same time all 3 no. of 400/220kV ICTs at Daulatabad(HVPN) also tripped due to earth fault protection.

4. As per SCADA SoE: Tie CB of 400kV Daulatabad-Dhanonda-2 tripped. Tripping of ICT #1 didn’t report in SoE, whereas in analog data flow becomes zero. As per SoE, Tie CB of 400kV Daulatabad-Dhanonda-2 & 400/220kV ICT #3 from 220kV

side tripped before the fault observed from PMU whereas 400/220kV ICT #2 tripped after the clearance of fault. It may be the issue of digital data synchronization.

5. ICTs Flow:

6. As per PMU data:

Max dip observed in Y-phase voltage. Fault clearing time ~ 2760ms.

7. PMU data of phase voltages:

8. SoE is given below:

Representative of Haryana informed that DR/EL was not available due to limited storage of DR in the relay. NLDC representative informed that this issue of DR/EL availability may be solved after implementation of automatic downloading facility of DR/EL in the sub-station.

1. In antecedent condition bus bar protection at 220kV Daultabad station was under outage due to replacement work of the same. ABB make static bus bar was being replaced with


ER make numerical relay.R-phase CT of Daultabad-Nunamajra ckt1 busted. It resulted into falling of jack bus on main bus. At the same time all 3 no. of 400/220kV ICTs at Daultabad (HVPN) also tripped due to earth fault protection.

2. Non availability of bus bar protection and clearance of fault after tripping of all three ICTs on earth fault protection resulted into delayed clearance of fault.

3. Bus Bar Protection has put into service from 11.03.2015. 4. Multiple element tripping due to operation ofback up protection of ICTs as bus bar

protection of 220kV bus didn’t operate. 5. DR/EL of the tripping didn’t provide by the Haryana. 6. Digital data didn’t available from 400/220kV Daultabad station.

1. Healthiness of Bus Bar Protection to be ensured. (Action: Haryana; Time Frame: 15 days)


2. Reason of tripping of tie CB of 400kV Daulatabad-Dhanonda-2 needs to be looked into. (Action: Haryana; Time Frame: 15 days)

3. Availability of DR/EL of Daultabad station to be ensured. (Action:Haryana; Time Frame: 1 months)

4. Availability of digital data of 400/220kV Daultabad station to be ensured. (Action: Haryana; Time Frame: 1 months)

5. Availability of standalone automatic downloading facility of DR/EL in the sub-station to be ensured. (Action: All the NR Constituent; Time Frame: 3months)

6. Haryana is continuously violating the IEGC clause 5.2.r & CEA Grid Standard 5.3 as Detailed report, DR/EL has not been received from Haryana in past also.

C. Multiple Element tripping at 400/220kV Ratangarh station on 16thFeb 2015 at 15:23hrs

Event category: GD-1 Generation loss:250MW (Rajasthan may confirm) Loss of load: Nil

Description




As per PMU data


Present Status

Remarks

Availability of Digital Data (SCADA Data) Partial

Available

DR/ EL Rajasthan Not Received Preliminary Report Rajasthan Not Received Detailed Report Rajasthan Not Received



IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; 43.4.A & 43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines; CEA (Technical standards for connectivity to the Grid) Regulation, 2007 Schedule Part-I.6 Protection Co-ordination CEA Grid standard 2010 -3.e CEA Transmission Planning Criteria

Rajasthan

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Availability of DR/EL 3. Availability of Bus Bar Protection 4. Protection Co-ordination


2. As reported string broken at Tower 171 for 400kV Ratangarh-Suratgarh-1. The aforesaid element

tripped along with 400kV Ratangrah-Merta & Unit #5(250MW) at Suratgarh TPS. 3. As per NR SoE, it seems along with aforesaid element all three 315MVA 400/220kV ICTs of

Ratangarh station also tripped at the same time. NR SoE is given below:

4. It seems digital data status of 400kV Suratgarh-Ratangarh ck-1&2 swapped to each other. 5. As per PMU data Fault in Y-phase with clearing time ~ 80ms

6. It is inferred from PMU & SoE data that fault was in 400kV Ratangarh-Suratgarh ckt1. At the same

time, 400kV Ratangarh-Merta, unit-5(250MW) of Suratgarh & ICTs at Ratangarh tripped. It seems bus bar protection operated at 400kV Ratangarh station.

7. As per Rajasthan Report:

8. Interim arrangement at Ratangarh Station:

1. In antecedent condition bus bar protection at 400kVRatangarh station was unstable& 400kV Suratgarh-Ratangarh ckt-2 was under outage. As reported string broken at Tower 171 for 400kV Ratangarh-Suratgarh-1. Due to interim arrangement, 400/220kV ICT-2 at Ratangarh station tripped. Planned SPS operation for tripping of 400kV Suratgarh-Ratangarh ckt-1 resulted into tripping of the unit-5 at 400kV Suratgarh station. 400kV Ratangarh-Merta ckt tripped due on over voltage protection & remaining ICT also tripped due to interim arrangement.


2. 400kV Bus Bar Protection at Ratangarh station retrofitted with Ratangarh-Sikar line. 3. Digital data status of 400kV Suratgarh-Ratangarh ckt-1&2 swapped to each other. 4. DR/EL of the tripping didn’t provide by the Rajasthan due to limited memory space in

numerical relay.

1. Interim arrangement of tripping of ICTs with the 400kV lines tripping to be reviewed and changed. (Action: Rajasthan; Time Frame: 7 days)


RemarksTrippi Closing One end/HV Other end/LV

400 KV Ratngarh-

STPS-I

16.02.15

15:2318:58 on

dt 17.02.15

Distance Protection Opreted ,Zone-I ,Phase C ,D=79.7KM ,Ia=0.37In ,Ib=.11In ,Ic=1.75In

,Va=1.04Vn ,Vb=0.84Vn ,Vc=0.66Vn ,R=1.65Ohms Trip ABC ,F=49.9Hz, Main-

II IL1=.76KA ,IL2=0.24KA ,IL3=0.66KA ,Rs=3.24Ohms ,Xs=14.4Ohms

,Rp=5.89Ohms ,Xp=26.25Ohms ,D=79.11KM ,d%=54.81% Phase-c, Auto

recloser Lockout 186A 186B , carrier recived

Distance Protection Opreted, Zone-I, Phase C, D=54KM,

Ia=0.79In, Ib=.33In, Ic=4.35In, Va=0.98Vn, Vb=0.98Vn,

Vc=.60Vn, F=49.9, R=.56Ohms, Trip ABC, Distance Protection Opreted M-II D=52.46KM, Z-I,

Phase-C Trip ABC

Disk Puncture

400 KV Ratangarh -Merta Line

16.02.15 15:23 16:37 O/V Protection opreted ,genral trip, Group-A

trip 86A ,Group-B 86

400 KV Ratangarh- Merta Line

16.02.15 20:53 22:37 O/V Protection opreted ,genral trip, Group-A

trip 86A ,Group-B 86

Relay IndicationsSr. No.

Name of G.S.S.

Name of Line/ Transformer

Time in hrs.Date of

400 KV GSS

Ratangarh1

Due to defective CVT ratio,.

2. CVT of 400kV Ratangarh-Merta line at Ratangarh end may be borrowed from POWERGRID & to be replaced. (Action: Rajasthan; Time Frame: 1 months)

3. Availability of DR/EL of Ratangarh station to be ensured. (Action: Rajasthan; Time Frame: 1 months)

4. Availability of digital data of 400/220kV Ratangarh, Suratgarh station to be ensured. (Action: Rajasthan; Time Frame: 1 months)

5. Rajasthan may submit the detailed report along with action taken report within 15days. 6. Availability of standalone automatic downloading facility of DR/EL in the sub-station to be

ensured. (Action: All the NR Constituent; Time Frame: 3months)

D. Tripping of HVDC Balia-Bhiwadi Bipole on 18th& 19thFeb 2015 at 10:51hrs& 12:11hrs respectively.

Event category: GI-2 Generation loss:Nil Loss of load: Nil (State utilities may confirm about the load loss)

Description Data Summary received at NRLDC:

Fault Info Remarks Fault Clearance Time No fault As per PMU data Phase of the fault NA As per PMU data


Present Status

Remarks

Availability of Digital Data (SCADA Data) Not Available

DR/ EL POWERGRID Received After 24hrs Preliminary Report POWERGRID Received After 24hrs Detailed Report POWERGRID 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 Electric Lines; CEA Grid standard 2010 -3.e CEA Transmission Planning Criteria

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

1. At 10:51hrs ±500kV HVDC Balia-Bhiwadi Bipole tripped due to false signal of valve cooling problem.


2. Report from POWERGRID:

3. No tripping observed in NR SoE. 4. As per PMU data no fault observed into the system. PMU plot of frequency& phase voltage given

below:

5. Reason of rise in the voltages yet to be unexplained. 6. On 19 Feb 2015 at 12:10 Hrs. Bi-pole was running 250 MW power (minimal Power) and electrode

line was unavailable at Bhiwadi due to line theft and ground was provided with station ground. Due to disturbance in Optical link dedicated to inter-station communication; frequency Limit control function activated in station mode and modulated power at both terminals, first at Ballia terminal which was followed by Bhiwadi to control the unbalance. This power Modulation caused unbalanced load which made this unbalance current flow through station ground. The station ground overcurrent protection actuated (setting of overcurrent is 37.5 A) because of this unbalanced current and this caused tripping of the Bi-pole one by one.

7. On 1st March 2015, at 19:43:11.0008hrs, Pole-2 blocked on DC overvoltage (V>1.024pu for 1sec) from Balia end. 19:43:13.811hrs, Pole-1 blocked from Bhiwadi end due to unavailability of earth electrode. Extract of tripping report is given below:

1. POWERGRID may brief about the “constraint in electrode line at Bhiwadi end”. Points for Discussion:

2. Reason of rise in the PMU plot of Balia voltage yet to be unexplained. 3. POWERGRID may implement the preventive measure for tripping ofHVDC Balia-Bhiwadi bipole. 4. Status of rectification of measuring of voltage on higher side. 5. Over voltage setting needs to be reviewed. 6. Availabilityof digital data to be looked into.

1. On 18.02.2015, Prior to Tripping of the pole Maintenance works were being carried out by the AMC engineer for attending the False Alarm of Low Battery voltage in UPS-1 of valve cooling system of Pole-1.


2. The UPS-1 was made off at time 10:44:51hrs (dt.18.02.2015) for checking the alarm ckt for battery voltage low (Battery voltage Low alarm was coming in SER though in UPS display panel Battery voltage was normal and in healthy condition 100%) and the UPS-2 was in service with Battery Voltage within Limits, bypass line within limits.

3. The Pole-1 VCS system was running on UPS-2 only. At time 10:51:10hrs the inverter of the UPS-2 gone Faulty and inverter gone Off. The automatic switching ON of the Static bypass hasn’t happened consequent to inverter gone faulty in the UPS-2 resulted failure

of power supply to the Pump and the Pole -l Tripped. Due to constraint of Electrode line at Bhiwadi end the Pole-2 tripped due to no GR path.

4. Automatic changeover scheme of the UPS supply has been changed. 5. In case of tripping on 19th Feb 2015, NRLDC raised the issue of simultaneous failure of both the

communication channel. 6. On 19th Feb 2015, exact reason of tripping couldn’t be explained by POWERGRID. 7. On 1st Mar 2015, there was a problem in convertor card resulted into tripping of pole-2 on over

voltage protection. Actual system voltage was in the normal range. It is a mal-functioning of control card. Card has been replaced at Balia end.

1. POWERGRID may furnish the complete scheme & modification in the scheme for UPS changeover. (Action: POWERGRID; Time Frame: 7 days)


2. POWERGRID may furnish the detailed investigation report in case of tripping on 19th Feb 2015, considering the simultaneous failure of both communication channels. (Action: POWERGRID; Time Frame: 7days)

3. Availability of digital data of HVDC Balia-Bhiwadi Bipole station to be ensured. (Action: POWERGRID; Time Frame: 1 months)

E. Multiple element tripping at 400/220kV Panipat(BBMB) on 1st Mar 2015 at 08:41hrs Event category: GD-1 Generation loss: Nil Loss of load: 100MW

Description


Fault Clearance Time 80ms, As per PMU data

Phase of the fault R-phase to ground fault

As per PMU data

Description Utilities Present Status Remarks


DR/ EL BBMB Received After 24hrs

Haryana Not Received

Preliminary Report BBMB Received After 24hrs


Detailed Report BBMB Received After 24hrs



Violation of Clauses 1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3

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

1. Connectivity Diagram:


2. In antecedent condition:

3. Fault on R-phase CT of Bus Coupler-2 at the area covered by overlapping by Zone-1 & Zone-3

resulted in surface tracking occurred between the CT primary terminal and the dead tank i.e. earth during raining. 220 KV Bus-1 (Z-1) & Bus-2RHS(Z-3) tripped and the feeders running on 220 KV Bus-1 & Bus-2RHS tripped off, the remote ends of these feeders remained charged as the fault was cleared instantly by the Bus Bar at BBMB Panipat end. Name of the tripped elements are given below:

4. 400 KV Dadri -2 tripped on Overvoltage as the 400KV voltage rose after sudden through off load

with the tripping of the220 KV Bus-Bar Protection. 5. As per PMU data:

From PMU, max. dip observed in R-phase. Fault occurred at 08:41:23.120hrs & cleared in 40msDip in the Freq: 0.023Hz

a. Fault occurred at 08:41:23.120hrs & cleared in 40msDip in the Freq: 0.023Hz As per PMU data fault clearance time was ~1540ms

6. PMU plot of phase voltages & frequency:

7. As per NR SoE:

a. As per SoE, CBs of feeders startedopening at 08:41:23.095hrs & opened within 50ms. b. 400kV Panipat-Dadri opened at 08:41:27.186hrs from Panipat end, around 4sec after the

fault. From PMU a slight rise in voltage observed at 08:41:27.280hrs.

8. NR SoE is given below:

1. Only one CT used across the bus coupler. Fault was on R-phase CT of Bus Coupler-2 at the area covered by overlapping by Zone-1 & Zone-3 resulted in tripping of 220 KV Bus-1 (Z-1) & Bus-2RHS(Z-3) and the feeders running on 220 KV Bus-1 & Bus-2RHS tripped off, the remote ends of these feeders remained charged as the fault was cleared instantly by the Bus Bar at BBMB Panipat end.

Protection Committee Outcome:

2. Tripping of 400kV Dadri-Panipat-2 in ~4sec of the fault on overvoltage. Setting of overvoltage may be shared.

1. Panipat (BBMB) revised the bus bar scheme with two CT across the bus coupler. (Action: BBMB; Time Frame: 3months)


2. Over voltage setting of different outgoing elements from Dadri to be revisedas per given below: a. 400kV Dadri-Mandaula ckt-1: 110% with 5second time delay b. 400kV Dadri-Mandaula ckt-2: 112% with 6second time delay c. 400kV Dadri-Panipat ckt-1: 110% with 5second time delay d. 400kV Dadri-Panipat ckt-2: 110% with 6second time delay

3. Availability of DR/EL & time synchronized digital data to be ensured. (Action: BBMB, Haryana; Time Frame: 3months)

F. Kashmir Valley Collapse on 2nd Mar 2015 at 05:20hrs & 06:50hrs Event category: GD-1

Generation loss: 1510MW Loss of load: 300MW

Description


Fault Clearance Time B-phase As per PMU data

Phase of the fault 300ms As per PMU data


Present Status

Remarks



DR/ EL

POWERGRID Partial Received

After 24hrs

NHPC Received After 24hrs

Punjab Not received J&K Not received

Preliminary Report

POWERGRID Not Received NHPC Received After 24hrs

Punjab Not received J&K Not received

Detailed Report POWERGRID Not received NHPC Received



1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 3. CEA (Technical standards for connectivity to the Grid) Regulation, 2007-6. 4.d 4. CEA (Technical standards for connectivity to the Grid) Regulation, 2007 Schedule Part-I.6 Protection Co-ordination

POWERGRID, NHPC

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Protection Co-ordination

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;

J&K

1. DR/EL, Preliminary report didn’t provide within 24hrs, 2. Availability of DR/EL at station

1. In antecedent condition weather was stormy. Load crash occurred in entire Northern Region. Around thirty 400kV lines tripped/manually opened due to high voltage into the system.


2. Kashmir valley is connected to the rest of the grid by following links : 400kV Kishenpur-New Wanpoh-Wagoora D/C 220kV Kishenpur-Mirbazar-Pampore-ckt-1 200kV Kishenpur-Ramban-Mirbazar-Pampore-ckt-2

3. Connectivity Diagram:

4. In antecedent condition 400kV Kishenpur-New Wanpoh ckt-2 tripped at 04:08hrs.In antecedent

condition power flow was from 400kV Wagoora-New Wanpoh-Kishenpur direction. (~180MW) 5. R-phase to Ground fault observed in Z-2 from Kishenpur end of 400kV Kishenpur-New Wanpoh

ckt-1. Carrier received from New Wanpoh end. Line tripped in Z-1 within 80ms. After 1000ms line auto reclosed but tripped due to permanent nature of fault. (05:20:28.768hrs).Immediately after tripping of the 400kV link, at 05:20:36.078hrs all the running unit of Uri HEP reportedly tripped on over frequency protection.

6. At 06:22hrs, charging attempt took for 400kV Kishenpur-New Wanpoh ckt-2. Line again tripped due to SOTF signal.

7. 220kV Salal-Jammu ckt-1 & 2 was already under tripped condition on earth fault protection. 8. At 06:50hrs, 400/220kV Kishenpur station became dead. (As per SCADA data).At the same time

Uri-I HEP, Dhauliganga, Baghlihar, Chamera-I, Chamera-II, Chamera-III HEP generation tripped. Kashmir valley collapsed at that time.

9. As per PMU data: Fault observed at 05:20:28.768hrs. Fault Clearance time was ~80ms. Maximum dip in R-

phase. At 06:50hrs, very high voltage observed at Kishenpur end.

At 06:50hrs, the dip in frequency was also observed indicating Loss of Generation>Loss of Load. Net rise in frequency was 0.02Hz

10. SCADA SoE data was not time synchronized 11. As per DR details:

Sarna-Kishenpur ckt1: Blue-phase to ground fault, Carrier received from Sarna. Blue phase tripped from both the end. B-phase auto reclosed from Kishenpur end but didn’t auto reclosed from Sarna end. From Sarna end line finally tripped in Z-3R at 06:49:44.076hrs. (Fault was in 220kV sarna-Kishenpur ckt1)

Sarna-Kishenpur ckt2: Fault current of the magnitude of 300A flowing through neutral. Line tripped from Sarna end after 1000ms in reverse zone or Z-3R because after that current die down and only charging MVAR was flowing. Line charged from Kishenpur end.

12. Extract of NHPC report is:

13. NR SoE is tabulated below:

14. On 17.03.2015, 400kV Kishenpur-New Wanpoh-Wagoora ckt1 was already under tripped

condition. Kashmir valley is importing power from rest of the NR grid. 400kV Kishenpur-New Wanpoh-Wagoora ckt2 tripped. At the same time 220kV Kishenpur-Ramban-Mirbazar-Pampore & Kishenppur-Mirbazar-Pampore section on over current protection. After isolation of valley from

rest of the grid. Uri-I HEP tripped due to under speed protection. All the elements connected to Wagoora station also tripped. Details from POWERGRID are still awaited. 480MW generation loss & 600MW load loss occurred in J&K area during the incident. Extract of NHPC report:

1. In antecedent condition, there was snowfall in valley area due to snowfall, valley load become very low and it resulted into widespread over voltage in that area. For controlling the voltage, 400kV Kishenpur-Moga ckt-1 manually opened at 00:12hrs, 400kV Kishenpur-Dulhasti manually opened at 00:47hrs & Kishenpur-Chamera2 manually opened at 03:02hrs.After opening/tripping of many 400kV lines in that area, 400kV Kishenpur station is loosely connected with the grid. At 06:50hrs, B-phase to ground fault occurred in 220kV Kishenpur-Sarna ckt-1& ckt-1 tripped in zone-1 time. At the same time 220kv Kishenpur-Sarna ckt-2 also tripped due to resistive reach setting problem. After tripping of both 220kV Kishenpur-Sarna ckts, Kishenpur is connected with one ckt of Moga (ckt-2). Power flow rose upto 2500Amp on 400kV Kishenpur-Moga ckt-2. This line tripped in zone-1 due to resistive reach setting problem in Micom relay.


2. Resistive reach setting in has been changed according to Ramakrishna committee report. 3. Reason of tripping of Chamera-II HEP units as 400kV Chamera-II Chamba ckt already under

charged condition: Chamba didn’t connect with rest of the grid. As 400kV Chamera2-Chamba ckt under charged condition without any power flow.

4. Report submitted by NHPC in the meeting:

5. On 17th Mar 2015, Kishnepur-New Wanpoh ckt-1&2 tripped due to snowfall. At the same time

remaining 220kV connectivity of Valley also tripped on overloading of 220kV lines.

1. Non-auto reclosing of 220kV Sarna-Kishenpur ckt-1 from Kishenpur end to be checked & corrected. (Action: POWERGRID; Time Frame: 7days)


2. Setting of reverse zone at 220kV Sarna end of 220kV Sarna-Kishenpur D/C needs to be reviewed. (Action: POWERGRID; Time Frame: 7days)

3. NHPC may review the staggering in over frequency setting of Uri-I HEP units. (Action: NHPC; Time Frame: 7days)

4. PDD-J&K may review the staggering in over frequency setting of Uri-I HEP units. (Action: PDD-J&K; Time Frame: 15days)

5. Planned SPS for Kashmir valley to be expedited. (Action: PDD-J&K) 6. Installation of UFR & df/dt relays to be expedited.(Action: PDD-J&K)

G. Multiple Element tripping at 400/220kV Bassi(PG) station on 5th Mar 2015 at 11:15hrs Event category: GD-1 Generation loss: Nil Loss of load: 550MW

Description



Phase of the fault B-phase to ground fault

As per PMU data


Availability of Digital Data (SCADA Data) Available Partially Available

DR/ EL POWERGRID Received After 24hrs

Rajasthan Not Received

Preliminary Report POWERGRID Received After 24hrs

Rajasthan Received After 24hrs

Detailed Report POWERGRID Received Rajasthan Not Received



1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 3. CEA Grid standard 2010 -3.e 4. CEA Transmission Planning Criteria

POWERGRID, Rajasthan

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Delayed Clearance of fault

1. 400/220kV Bassi station is connected with D/C Jaipur(S), D/C Heerapura, D/C Phagi, S/C Kotputli, S/C Bhiwadi and S/C Agra. It has two ICTs of 315MVA and one ICT of 500MVA at 400/220kV level. At 220kV side, connected with D/C Dausa, S/C Kukas, S/C Kunda ki Dhani, S/C IG Nagar/Jagatpura, S/C Bagru. Single Line Diagram:


2. Main CB of 220kV Dausa-2 was under S/D, line was in service through Transfer CB 3. Due to problem in Aux. switch of Bus-II isolator of Dausa-2, “CT switching incomplete” alarm was

persisting and same was being rectified. During rectification, Bus-2 isolator closed inadvertently which converted into bus fault. In antecedent condition, bus bar protection was bypassed.

4. As reported remaining 220kV lines was tripped from remote end in Zone-2. 5. ICT-1,2 tripped at Back-up protection from HV side & ICT-3 tripped on PRD protection. 6. As per PMU & SCADA Data:

From PMU, max. dip observed in R-phase voltage magnitude. Fault occurred at 11:15:09.840hrs& cleared in 1120ms.

As per SoE, ICT #2 tripped at 11:15:12,743hrs 7. PMU data plot:

8. It seems from the DR of ICTs that fault occurred at 11:15:09:850hrs& ICT #1 & #2 tripped at

11:15:10:930hrs. 9. NR SoE:

1. Due to problem in Aux. switch of Bus-II isolator of Dausa-2, “CT switching incomplete” alarm was persisting and same was being rectified. During rectification, Bus-2 isolator closed inadvertently which converted into bus fault. In antecedent condition, bus bar protection was bypassed. Fault was on 220kV bust, all the elements tripped from remote end in zone-2 or zone-3 due to bypassing of bus bar protection.

Protection Committee Outcomes:

2. Delayed clearance of fault persisted due to non-availability of bus bar protection in antecedent condition.

3. Bus bar protection was okay, it was manually bypassed for working on the isolator. Same has been put into the system after completion of the work.

4. PRD (Pressure Relief Device) 400/220kV ICT #3 of Bassi (PG) mal-operated.

1. PRD mal-operation of 400/220kV ICT-3 at Bassi (PG) end to be checked & corrected. (Action: POWERGRID; Time Frame: 1month)


2. Availability of time synchronized digital data to be ensured. (Action: POWERGRID; Time Frame: 1month)

H. Multiple Element tripping at 400kV Obra (TPS) on 11th Mar 2015 at 06:04hrs

Event category: GD-1 Generation loss: 257MW (UP may confirm) Loss of load: Nil (UP may confirm)

Description


Fault Clearance Time No fault observed

As per PMU data

Phase of the fault NA As per PMU data




DR/ EL UP Not Received Preliminary Report UP Not Received

Detailed Report UP Not Received



IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; 43.4.A & 43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines; CEA (Technical standards for connectivity to the Grid) Regulation, 2007 Schedule Part-I.6 CEA Grid standard 2010 -3.e CEA Transmission Planning Criteria

UP

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Availability of DR/EL 3. Availability of Bus Bar Protection 4. Protection Co-ordination

1. Connectivity Diagram is given below: Based on above information description of the events is:

2. 400kV Obra-B TPS connected with S/C Anpara, S/C Bara, S/C Sultanpur. It has five units of

200MW. 3. In antecedent condition unit-9, 12 & 13 was under running condition. 4. At 06:04hrs Busbar (A Bus) protection operated at Obra-B TPS, this caused tripping of all three

feeders 400 kV Obra-Bara, Obra-Sultanpur, Obra-Anpara along with Unit No 9 &12 the running on that Bus.

5. 400 kV Bara-Obra & Bara Panki also tripped from Bara end. 6. Generation loss of 120(12number)+137(9number)=257 MW(then generating before tripping) 7. Unit No13 (125 MW) & ICT-1 &2 (50MW each) at Obra was charged and meeting the load (not

tripped). 8. As per PMU data, Slight voltage dip at 06:04:12.880hrs 9. PMU plot of phase voltages & frequency given below:

10. SCADA SoE:

11. Probable SoE:

1. No Person from UPRVUNL attended the meeting. It has been observed in the past also that no person from Uttar Pradesh Rajya Vidyut Utapadan Nigam limited attended the meeting. SLDC kindly ensure the presence of UPRVUNL in the meeting.


2. UPRVUNL submit the detailed report within 7days considering the following point: a. Location of fault & Reason of fault. b. Healthiness of bus bar protection to be looked into. c. Reason of tripping of all the transmission elements at the same time. d. Connectivity of the tripped elements. e. Reason of tripping of 400kV Bara-Panki line.

3. Availability of Bus Bar Protection to be ensured. (Action: UPRVUNL; Time Frame: 2months) 4. Availability of time synchronized digital data to be ensured. (Action: UPRVUNL; Time Frame:

30days) 5. Availability of time synchronized DR/EL to be ensured. (Action: UPRVUNL; Time Frame: 30days)

I. Multiple Element tripping at 765kV Anta(Raj) at 18:13hrs of 14th Mar 2015 Event category: GD-1 Generation loss: 280MW Loss of load: Nil

Description




As per PMU data


Availability of Digital Data (SCADA Data) Partial Available


DR/ EL Rajasthan Not Received Preliminary Report Rajasthan Received After 24hrs

Detailed Report Rajasthan Not Received After 24hrs



1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 3. CEA (Technical standards for connectivity to the Grid) Regulation, 2007-6. 4.d 4. CEA (Technical standards for connectivity to the Grid) Regulation, 2007 Schedule Part-I.6 Protection Co-ordination

Rajasthan

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Protection Co-ordination

1. 765/400kV Anta(Raj) station connectivity diagram is given below: Based on above information description of the events is:

2. 765/400kV Anta station has three 765/400kV 1500MVA ICTs & D/C Phagi line. At 400kV level, connected with D/C Kalisindh, D/C Kawai. Its have one an half breaker scheme.

3. In antecedent condition 400kV Anta- Kalisindh-2 was out since 18-02-2015, to reduce loading on 315 MVA ICT at Kalisindh.

4. Tripped Elements: 765kV Anta-Phagi D/C 400kV Anta-Kawai(Adani) D/C 400kV Anta- Kalisindh-1 400kV Chhabra-Kawai(Adani) One unit of Chabra TPS One unit of Kalisindh.

5. As per PMU data, Maximum dip observed in Y-phase. 6. Fault started at 18:13:27.440hrs & cleared in ~ 80ms. Fault again observed after ~ 1sec at

18:13:28.520hrs & cleared in ~ 80ms 7. As per NR SoE:

8. 765kV Phagi-Anta-1, 400kV Kalisindh-Anta-1 & 765/400kV ICT #2 at Phagi tripped. 9. PMU plot of phase voltage & frequency:

10. Probable SoE:

1. In antecedent condition one bus was operational at 765kV Anta end. 765kV Anta-Phagi ckt-1 was charged through tie CB & 765/400kV ICT-1 was charged through main breaker. Similarly 765kV Anta-Phagi ckt-2 charged through tie CB & main CN of ICT-2. 765/400kV ICT-2 was under commissioning stage.


2. At 18:13 hours on March 14, 2015 under heavy storm conditions, there was Y-phase to ground fault in 765kV Anta-Phagi circuit 1, line finally tripped after unsuccessful auto reclosing. Relays showing fault Location at 56.48kM from Anta end. 765kV Anta-Phagi circuit 2 tripped at 765kV Anta on Differential Relay connected to Bus breaker of the Line as the CB is common for ICT 2

which has not been commissioned but relay status was enabled (Main CT & tie CT ratio was different, at the time of fault in the line differential current observed & differential relay operated).Tie CT has been changed to same CT ratio.

3. One unit of Kawai also tripped on planned SPS operation. 4. 400kV Anta-Kawai ckt#2 tripped on DT signal received from APRL Kawai end as their plant had

tripped. 400kV Anta-Kawai circuit #1 tripped on O/V relay. 5. 400kV Anta-Kalisindh ckt-1 also tripped on over voltage protection. 6. After investigation tower damage found in the 765kV Anta-Phagi circuit-1. 7. 400kV Anta-Kawai ckt#2 tripped on DT signal received from APRL Kawai end as their plant had

tripped. 400kV Anta-Kawai circuit #1 tripped on O/V relay. 8. After discussion in various OCC meeting about furnishing the DR/EL within 24hrs of the event by

the utilities to RLDC/RPS however after ~6month details are still awaited from Rajasthan. Details are still awaited from Rajasthan in most of the cases. Rajasthan is continuously violating the grid clause IEGC 5.2.r.

1. Rajasthan may kindly furnish the details (DR/EL & Preliminary Report) of the tripping within 24hrs of the event and also furnish the detailed report within 15days of the event.


2. DR of 765kV Anta-Phagi ckt-1 to be time synchronized. (Action: Rajasthan; Time Frame: 7days) 3. Over voltage setting of 400kV Anta-Kalisindh ckt-1 to be checked & corrected. (Action: Rajasthan;

Time Frame: 7days)

J. Complete Outage of 400kV Bareilly(UP) station on 21st Mar 2015 at 08:59hrs

Event category: GD-1 Generation loss: Nil Loss of load: 225MW

Description




As per PMU data


Availability of Digital Data (SCADA Data) Available Partially Available

DR/ EL UP Not Received POWERGRID Received After 24hrs

Preliminary Report UP Received At the time of meeting

POWERGRID Received After 24hrs

Detailed Report UP Not Received POWERGRID Received



1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 3. CEA Grid standard 2010 -3.e 4. CEA Transmission Planning Criteria

POWERGRID

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Delayed Clearance of fault 3. Protection Co-ordination


1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 3. CEA Grid standard 2010 -3.e 4. CEA Transmission Planning Criteria 5. CEA (Technical standards for connectivity to the Grid) Regulation, 2007 Schedule Part-I.6 Protection Co-ordination

UP

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Delayed Clearance of fault 3. Protection Co-ordination

1. Connectivity Diagram of BareillyUP) : Based on above information description of the events is:

2. At 08:59hrs, due to Flashover in corona ring of transfer bus at Bareilly s/s, Busbar protection

operated and following elements tripped. 400kV Bareilly(UP)-Unnao-D/C 400kV Bareilly(UP)-Bareilly-D/C 315MVA, 400/220kV ICT-I and II at Bareilly(UP)

3. From PMU it was observed that fault was in Y-Phase because maximum dip was observed in Y-Phase of Meerut PMU.

4. Fault clearance time was 1120ms milliseconds which lead to multiple tripping at Bareilly(UP) S/s. 5. Load loss of 270MW occurred which can be confirmed by the frequency rise of 0.017Hz. 6. Supply to Nepal was also disturbed in this disturbance which resumed at 09:40hrs 7. PMU plot:

8. NR SoE:

9. As per NR SoE, it seems all the elements tripped at different time. Bus Bar Protection didn’t

operate at 400kV Bareilly(UP) station. 10. 400kV Bareilly(PG)-Bareilly(UP) D/C tripped from Bareilly(PG) end in Zone-2 after ~400ms.

However as per SoE 400kV Bareilly(UP)-Bareilly(PG) D/C tripped from Bareilly(UP) first. 11. As per NR SoE 400kV Bareilly(UP)-Unnao ckt tripped at 08:58:50.482hrs from Unnao end

1. In antecedent condition, bus bar protection was under outage due to commissioning of new 400/220kV ICT-3 at Bareilly (UP). Although this ICT was charged through transfer breaker. Outage of bus bar protection didn’t require for charging of third ICT.

Protection Committee Conclusions:

2. Y-phase to earth fault occurred on the main bus-1 due to falling of stell wire used for kite flying. As bus bar protection was not available, this bus fault resulted into tripping of all the 400kV lines from remote end in zone-2 or zone-3 and 400/220kV 315MVA ICTs tripped on backup earth fault/ over current protection.

3. Delayed clearance of fault was due to non-availability of bus bar protection at 400/220kV Bareilly (UP) station.

4. DR/EL couldn’t be extracted due to occurrence of many tripping after the incident and relay have limited memory.

5. Action taken by UPPTCL: a. M/s ABB have been assigned the work to supply necessary hardware and commissioning

of busbar wiring of ICT-3. b. Relays of Unnao end of 400kV Bareilly-Unnao line has been checked & tested during

routine testing and found normal. c. M/S ABB has inspected old RDSS bus bar protection at the site and process has been

initiated for work of recommissioning of busbar protection by them. d. All relays except of 220kV Dhauliganga & Pithoragarh have been time synchronized with

GPS clock. e. Reverse zone timing has been reduced to 160ms with reach of 2kM in reverse direction. f. Event logger commissioned on Unnao-1,2 line & ICTs.

g. Bus coupler breaker didn’t open during the incident. Same has been replaced on 21.09.2015

6. Time synchronization of digital data to be looked into.

1. Availability of new numerical bus bar protection to be ensured. (Action: UPPTCL; Time Frame: 2months)


2. Distance zones setting of 400kV Bareilly-Unnao line to be reviewed according to Ramakrishna committee task force recommendations. (Action: UPPTCL; Time Frame: 7days)

3. Availability of time synchronized digital data to be ensured. (Action: UPPTCL; Time Frame: 7days) 4. Availability of DR (Disturbance recorder)/EL (Event logger) to all the 400&220kV element at

400/220kV Bareilly(UP) station to be ensured. (Action: UPPTCL; Time Frame:45days) 5. Availability of automatic download facility of DR & standalone EL to be ensured. (Action: UPPTCL;

Time Frame:45days)

K. Complete Outage of 400/220kV Sultanpur Station on 1st Apr 2015 at 22:22hrs:

Event category: GD-1 Generation loss: Nil Loss of load: 180MW (As per UP Report)

Description



Phase of the fault Y-phase to ground fault As per PMU data


Availability of Digital Data (SCADA Data) Available Time Synchronization is not

okay

DR/ EL UP Not received Printout of DR/EL not

available

POWERGRID Not received

Preliminary Report UP Received After 24hrs

POWERGRID Not received

Detailed Report UP Received




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

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; CEA Grid standard 2010 -3.e CEA Transmission Planning Criteria

UP

1. DR/EL, Preliminary report didn’t provide within 24hrs, 2. Availability of DR/EL at station 3. Delayed Fault Clearance

1. 400kV Sultanpur station have three 400kV circuits; 400kV Obra-Sultanpur, Sultanpur-Lucknow(PG) & Sultanpur-Azmgarh circuit. Also have two 400/220kV 240MVA ICTs.


2. SLD of 400/220kV Sultanpur Station is given below:

3. In antecedent condition,400kV Sultanpur-Lucknow (PG) charged through transfer bus coupler as

main CB of this line was under S/D for replacement with new SF6 type CB&Power Flow on both the ICTs was ~90MW each.

4. An internal phase to earth fault occurred on Y-phase CT installed on 400kV transfer bay through which 400kV Sultanpur-Lucknow (PG) line was running (main CB was under S/D for replacement with new SF6 type CB).

5. As this CT is between transfer bus CB and transfer bus isolator of this bay, and since this TBC CB was charged through 400kV Bus B. It resulted into bus fault for Bus B (Y phase to earth bus fault). Bus Bar Differential Protection operated to isolate Bus-B along with Bus coupler, but all the elements of Bus-A also tripped. This resulted in complete 400kV supply failure at Sultanpur S/S.

6. 240 MVA, 400/220 kV ICT-I has isolator auxiliary contact problem leading to chattering of VAJC relay of this bay and hence was made permanently picked up for 400kV Bus A through which ICT-I was running earlier.

7. Recently ICT-I was charged through 400kV Bus-B. So, Bus Bar Protection which should have tripped CB of 400kV Bus coupler, 400kV Lucknow, 400kV Obra and 400kV ICT-I, it tripped all the 400kV circuit breakers treating the Bus A and Bus B as single bus because interconnector relay was picked up for both bus isolators of 400kV ICT-I and CB of 400kV PGCIL Lucknow (TBC), Azamgarh, Obra, Bus coupler and ICT-II tripped.

8. 400kV Lucknow (PGCIL) continued feeding fault current for 412ms till the line CB tripped in Zone 2 from Lucknow PGCIL end.

9. PLCC cabinets (BPL made) both main-I and main-II installed on 400kV Lucknow(PG) line are lying defective for past few months and PGCIL have been informed.

10. Direct trip command was issued to 400kV Azamgarh and Obra ends leading to tripping at those ends.

11. Probable SoE is tabulated below (on behalf of all sources):

12. Consolidated Flag details are given below:

13. Restoration time:

14. Remedial action to be taken (As per UP Report)

• Event logger to be commissioned on priority for timely and correct fault tripping analysis. (Action UPPTCL)

:

• Auxiliary contacts of 400kV Bus-A isolator of 400/220 KV ICT-I to be replaced. (Action UPPTCL)

• PLCC cabinets (main-I and main-II) of 400kV Lucknow (PGCIL) line to be set right by M/S PGCIL for correct carrier inter tripping. (Action PGCIL)

• Bus Bar Protection Relay (English electric type CAG-34) to be replaced by new bus bar protection relay panel. (Action UPPTCL)

• Tripping scheme/circuit of 400/220 KV 240 MVA ICT-I be checked. (Action UPPTCL)

1. Availability & Healthiness of bus bar protection scheme at 400kV Sultanpur station to be ensured. (Action: UPPTCL; Time Frame: 1months)


2. Reason of delayed clearance of fault couldn’t conclude due to non-availability of complete DR/EL & time synchronized digital data.

3. Availability of time synchronized digital data to be ensured. (Action: UPPTCL; Time Frame: 7days) 4. Availability of DR (Disturbance recorder)/EL (Event logger) to all the 400&220kV element at

400/220kV Sultanpur (UP) station to be ensured. (Action: UPPTCL; Time Frame:45days) 5. Availability of automatic download facility of DR & standalone EL at 400kV Sultanpur (UP) to be

ensured. (Action: UPPTCL; Time Frame:45days)

L. Complete outage of 400/220kV Muradnagar(UP) station on 8th Apr 2015 at 05:36hrs

Event category: GD-1 Generation loss: Nil Loss of load: 500MW

Description


Fault Clearance Time ~6second As per PMU, DR & SCADA SoE data



Availability of Digital Data (SCADA Data) Available Partial. Time Synchronization

is not okay

DR/ EL UP Received Partial Available. After 24hrs

NTPC Not received

Preliminary Report UP Received

NTPC Not received





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

Violation of Clauses 1. CEA Grid standard 2010 -3.e 2. CEA Transmission Planning Criteria 3. CEA Technical Standard for Construction of Electrical Plants and Electric Lines: 43.4 .A. 4. CEA (Technical standards for connectivity to the Grid) Regulation, 2007: Schedule Part 1. ( 6.1, 6.2, 6.3)

UP

1. Delayed Fault Clearacne Time 2. LBB/Bus Bar Protection Operation 3. Every element of the power system shall be protected by a standard protection system having the required reliability, selectivity, speed, discrimination and sensitivity

1. Single Line Diagram of 400/220kV Muradnagar Station is:


2. It has been reported by UPPTCL site that at 400kV S/S Muradnagar, Y-phase pole of CB of 400kV

Agra-Muradnagar line bursted. It resulted into bus bar protection/LBB operation at 400kV Muradnagar station. Isolators at Muradnagar station have been recently changed. It is suspected by UPPTCL that VAJC relay for automatic CT selection may not have correctly selected the bus bar & has send the trip command to both the buses. All 400kV elements except 400/220kV ICT-3(already under Shut down) tripped due to bus bar protection operation.

3. Antecedent Connectivity:

4. Max dip in Y-phase was observed. Time of fault was 05:36:49.120hrs& fault duration was ~80ms. 5. Fault was in 400kV Agra-Muradnagar line. Y-phase pole of CB of 400kV Agra-Muradnagar line

bursted at Muradnagar end. 6. As per PMU it seems, ICTs tripped after ~6seconds of the fault. It resulted into rise in the

frequency. 7. Flag details:

8. As per DR details

Y-phase CB of 400kV Agra-Muradnagar line didn’t open from Muradnagar end at 05:36:49.160hrs

400kV Muradnagar-Dadri tripped at 05:36:52.760hrs 400kV Muradnagar-Panki tripped at 05:36:55.648hrs

9. NR SoE:

10. As per SCADA SoE, 400kV Agra-Muradnagar line opened at the time of fault, first from Agra end

then from Muradnagar end at 05:36:49.144hrs. At ~05:36:54hrs Dadri-Muradnagar & Muzaffarnagar-Muradnagar line tripped from remote end. At ~05:36:55hrs ICT-3 tripped

11. Complete digital data of Muradnagar station is not available in NR SoE. 12. Restoration Time:

13. Maximum dip in blue phase & fault clearance time was 80ms

1. UPPTCL reported that standalone event logger facility would be available at 400/220kV Muradnagar end by the end of October-2015.

Protection Committee outcome & Recommendations:

2. Reason ofdelayed clearance of fault in case of busbar protection couldn’t conclude due to non-availability of time synchronized digital data, DR/EL details.

3. Healthiness of bus bar protection at 400/220kV Muradnagar end to be checked & corrected. (Action: UPPTCL; Time Frame: 15months)

4. Manual checking of VAJC relay (isolator selection switch) in case of isolator operation to be properly monitored. (Action: UPPTCL; Time Frame: 15months)

5. Availability of all digital data of Muradnagar sub-station in NR SCADA & its time synchronization needs to be ensured. (Action: UPPTCL; Time Frame: 15months)

M. Complete Outage of 220kV Raebareilly(PG) on 10th Apr 2015 at 13:53hrs Event category: GD-1 Generation loss: 400MW Loss of load: 250MW

Description


Fault Clearance Time 480ms As per PMU, DR & SCADA SoE data




DR/ EL

POWERGRID Not Received

UP Not received

NTPC Not received

Preliminary Report


UP Not received

NTPC Not received

Detailed Report POWERGRID Received



1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 3. 43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines; 4. CEA Grid standard 2010 -3.e 5. CEA Transmission Planning Criteria

NTPC, POWERGRID

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Availability of DR/EL facility at the station 3. Fault Clearance time more than 160ms


1. CEA Grid standard 2010 -3.e 2. CEA Transmission Planning Criteria 3. CEA Technical Standard for Construction of Electrical Plants and Electric Lines: 43.4 .A.

UP

1. Delayed Fault Clearacne Time 2. LBB/Bus Bar Protection Operation

1. 220kV Raebareilly(PG) station have five 220kV ckts: one ckt to Chinhat, one ckt to Lucknow(UP) & three ckt to Unchahar TPS. It has DMT (Double main transfer) scheme


2. On 10-April-15, a wire was found hanging from top of gantry to insulator string Y-phase of bus coupler & it is reaching up to 7th insulator disk causing flashes whenever wind blows.

3. Shutdown of 220KV Bus-2 was requested for removal of wire which may cause bus fault in future

if left unremoved. 4. At that time ICT-2, Chinhat & Unchahar-2 circuits on Bus -2. 5. To avail Bus Shutdown, ICT-2, Chinhat & Unchahar-2 needs to be transferred to Bus -1 for

removal of wire from Bus Coupler Gantry. 6. At first, ICT-2 was shifted to Bus-1. During transfer of Unchahar Line-2, after closing of Bus-1

Isolator, tripping incident took place during opening of Bus-2 Isolator. 7. During transferring the feeders from Bus-2 to Bus-1, Bus Coupler was inadvertently remained

open. As both isolators for Unchahar Line-2 was in closed condition, Bus Bar protection (RABH relay) was remain in blocked condition and all feeders tripped form remote end in Backup zones.

8. As per PMU data fault clearance time: ~480ms and voltage dip in all three phases 9. Only Lucknow(UP) ckt tripping observed in NR SoE. Extract of NR SoE:

1. Tripping was basically due to manual error during isolator switching. Measures should be taken to ensure that such events do not get repeated. These events may provide fatal to the operator.

Portection Committee Outcome & Recommendations:

2. Fault cleared with time delay due to blocking of bus bar protection in 220kV Raeareilly (PG) station and finally all the 220kV lines tripped from remote end in zone-2 timing.

3. Blocking of the bus bar protection during shifting of the isolator is not a healthy practice. Bus bar protection scheme to be reviewed

4. Unchahar unit tripped due to drop in the contractor of auxiliary supply of LT side of the unit.

5. Healthiness & setting of 220kV bus bar protection scheme at 220kv raebareilly (PG) to be reviewed. (Action: POWERGRID; Time Frame: 15days)

6. Senstitve setting of auxiliary contractor of unchahar units to be corrected. It may be coordinated with zone-3 setting of line protection. (Action: NTPC; Time Frame: 15days).

7. Availability of digital data to be ensured. (Action: POWERGRID, NTPC; Time Frame: 15days)

N. Complete outage of Harduaganj station and one unit tripping at NAPS at 11:15hrs of 16th Apr 2015 Event category: GD-1 Generation loss: 460MW Loss of load: 470MW

Description





Availability of Digital Data (SCADA Data) Available Partial Available

DR/ EL UP Not Received Only Flag details

NAPS Not received Only Flag details

Preliminary Report UP Received

NAPS Received


NAPS Received



1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 3. 43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines; 4. CEA Grid standard 2010 -3.e 5. CEA Transmission Planning Criteria

UP

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Availability of DR/EL facility at the station 3. Fault Clearance time more than 160ms

Violation of Clauses 1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 NAPS 1. DR/EL, Preliminary report

didn’t provide within 24hrs

1. 220kV Harduganj station connectivity diagram is given below: Based on above information description of the events is:

2. In antecedent condition, 220kV bus bar protection at Harduaganj station was out of service. Unit

number-5&8 was already under shutdown. 3. Both the units of NAPS were operating and generating about 215 MW (e) & 223 MW (e)

respectively. Prior to incident all five power evacuation lines were in service. 4. It has been reported by UPRVUNL site that at 11:15hrs, Y-phase CT of 220kV Harduaganj-

Jahangirabad ckt2 bursted at 220kV Harduaganj station. It resulted into bus fault for 220kV Harduaganj station but bus bar protection was not in service. It resulted into tripping of all the elements from remote end. Onlu running unit-9 of Harduaganj station also tripped due to non-clearance of fault. Therefore complete 220kV supply failed at Harduaganj TPS & adjoining areas. Also at NAPS, unit no. I tripped at the same time.

5. NAPS-Atrauli tripped at NAPS end through E/F protection as fault was not cleared at Atrauli end protection.

6. NAPS-Khurja-1&2 tripped at NAPS end through ABC, Z3 fault protection as fault was not cleared in time at Khurja end. However at same time BFR relay for NAPS-Khurja line-2 also got operated which led to tripping of GT-1, SUT-2 NAPS-Simbholi line, NAPS- Atrauli line (already tripped on E/F)

7. Tripping of GT-1 on BFR of NAPS-Khurja line-2 resulted in over speeding and changes in process parameters and caused tripping of Turbine Generator-1 and subsequently reactor trip.

8. Flag details of Harduaganj end:

9. Flag details of Khurja end:

10. Details of NAPS end:

11. NAPS-Simbholi line was remained energized from Simbholi end, CB at NAPS end was closed

after consultation with NRLDC and Officials Simbholi as only NAPS –Sambhal line left in service. 12. NAPS-Khurja line-1 was charged from NAPS as per NRLDC code at 12:08 hours. 13. NAPS-Atrauli line was charged from Atrauli end and line was taken in service at NAPS end as per

NRLDC code at 13:21 hours. 14. NAPS-Khurja line-2: BFR scheme was checked and its timer set at 300 ms was found defective

and its set time was observed to be 14 ms against required 300ms. Defective time relay for BFR was replaced

15. Reasons for turbine-1 trip BFR timer failure are being further investigated. 16. As per PMU data fault clearance time was ~3200ms. 17. Restoration time of the different elements:

1. Delayed Clearance of fault needs to be looked into: Due to non-availability of bus bar protection and lines finally tripped from remote end in zone-2 & zone-3.

Point wise reply by the constituents:

2. Zone-3 setting of every outgoing feeders of NAPS line was ~800ms. Same has been changed to 1000ms.

3. Non-operation of distance protection at Harduaganj end of 220kV Harduaganj-Jahangirabad ckt-2 to be looked into: Relay has been found healthy, put under observation by UPPTCL.

4. Availability of bus bar protection at 220kV Harduaganj station: Not available now. 5. Reason of non-operation of main and backup protection at Khurja & Atrauli: Khurja & Atrauli end

zone-3 protection operated. 6. Delayed tripping of 220kV Harduaganj-Khair & 220kV Harduaganj-Etah line from remote end.

(More than Zone-3R timing at Harduaganj end) 7. Non-operation of zone-2 at remote end of Harduaganj station as fault was at Harduaganj S/S. 8. Reason of tripping of 220kV Khurja-Dadri, Jahangirabad & Sikandrabad: These feeders are

connected on under voltage protection, these lines tripped on under voltage protection. 9. Backup earth fault settings in NAPP outgoing lines are: 10% with definite time delay of 1.5second. 10. LBB protection setting timer was 0ms instead of 200ms. This time delay has been changed to

200ms. 11. Reason of poisoning out of nuclear reactor as power supply was available at the sub-station: After

isolating the bus, GT-1 tripping resulted into over speeding in the generator and changes in the process parameter of turbine. Turbine finally tripped on boiler level high, after tripping of turbine partial supply failure occurred and it resulted into auxiliary supply failure of the reactor and reactor finally tripped. Poisoning of the reactor depends on the reactivity available in the nuclear reactor & control road position.

12. Availability of digital data: To be checked by UPPTCL, NAPS & UPRVUNL 13. Availability of DR/EL facility at the 220kV Harduganj, Khurja, Mainpuri, Atrauli, Jahagirabad, Khair,

Etah etc: Not available now

14. No Person from UPRVUNL attended the meeting. It has been observed in the past also that no person from Uttar Pradesh Rajya Vidyut Utapadan Nigam limited attended the meeting

1. NAPP may look into the issue of poisoning of nuclear reactor. Further improvement to be expedited. (Action: NPCIL; Time Frame: 2months)

Protection Committee Recommendation:

2. Availability of time synchronized digital data to be ensured. (Action: NPCIL, UPRVUNL; Time Frame: 1months)

3. Availability of DR/EL facility at the 220kV Harduganj, Khurja, Mainpuri, Atrauli, Jahagirabad, Khair, Etah etc to ensured. (Action: UPPTCL,UPRVUNL; Time Frame: 3months)

4. Availability of bus bar protection at 220kV Harduaganj station to be expedited. (Action: UPRVUNL; Time Frame: 1months)

5. Overall protection system of 220kV Harduaganj & nearby area needs to be checked & corrected& Protection co-ordination also needs to be reviewed. (Action: UPRVUNL; Time Frame: 1months)

6. Zone-2 & 3 settings are the associated line from Harduaganj to be checked & corrected.(Action: UPRVUNL; Time Frame: 1months)

7. Independent third party Protection Audit for 220kV Harduaganj station to be done. (Action: UPRVUNL; Time Frame: 2months)

Q. Multiple Element tripping at 400/220kV Bhiwadi(PG) and 500kV Balia-Bhiwadi Bipole on 29th Apr

2015 at 16:42hrs Event category: GD-1 Generation loss: Nil Loss of load: 350MW

Description



Phase of the fault B-phase to ground fault As per PMU data



DR/ EL Rajasthan Not Received


Preliminary Report Rajasthan Not Received


Detailed Report Rajasthan Not Received



Violation of Clauses 1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 Rajasthan 1. DR/EL, Preliminary report


3. 43.4.D of CEA Technical Standard for Construction of Electrical Plants and Electric Lines; 4. CEA Grid standard 2010 -3.e 5. CEA Transmission Planning Criteria

2. Availability of DR/EL facility at the station 3. Fault Clearance time more than 160ms

Violation of Clauses 1. IEGC 5.2.r & 5.9.6.c (VI) 2. CEA grid Standard 15.3 POWERGRID 1. DR/EL, Preliminary report



2. Due to B-ph CT failure of 220 kV Bhiwadi-Rewari ckt, 220kV Bhiwadi(PG)-Kushkhera(RVPNL)

D/C, 220kV Bhiwadi(PG)-Rewa SPL(HVPNL) & 500kV Balia-Bhiwadi bipole tripped. 3. NR SoE:

4. Maximum dip observed in B-phase voltage and fault clearance time ~1320ms 5. Digital data of Balia-Bhiwadi bipole tripping didn’t capture in NRLDC SoE.

1. Operator working on 220kV Bhiwadi-Rewari line for attending the fuse failure, because one distance relay was blocked due to fuse failure. Operator opened the other fuse of the relay resulted into blocking of main-II distance protection and simultaneously fault occurred into the system. All the 220kV lines tripped from remote end in zone-2 & zone-3 timing.

Points for Discussion:

2. HVDC Balia-Bhiwadi bipole tripped on negative sequence over current protection. 3. Delayed clearance of fault was due to blocking of distance protection in the line and lines finally

tripped from remote end. 4. Digital data availability needs to be ensured. (Action: POWERGRID, Rajasthan; Time Frame:

15days) 5. Sensitive setting of Negative sequence over current protection setting for Bipole to be checked &

corrected. (Action: POWERGRID, Rajasthan; Time Frame: 15days)

O. Multiple element tripping at 400kV Akal & Wind generation on 22nd May 2015 at 09:00hrs Event category: GD-1 Generation loss: 600MW Loss of load: Nil

Description


Fault Clearance Time No Fault observed

As per PMU data

Phase of the fault Open conductor fault

As per details available with Rajasthan


Present Status

Remarks


DR/ EL Rajasthan Partial Received

After 24hrs

Preliminary Report Rajasthan Received After 24hrs

Detailed Report Rajasthan Not Received



IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; CEA (Technical standards for connectivity to the Grid) Regulation, 2007 Schedule Part-I.6 Protection Co-ordination CEA Grid standard 2010 -3.e CEA Transmission Planning Criteria

Rajasthan

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Protection Co-ordination 3. Delayed Clearacne of fault


2. The disturbance was occurred due to opening of Y-phase jumper at Loc. No. 231 of 400 kV Akal-

Barmer Line which was charged at 08:54hrs after erection of towers. Due to this unbalance currents flow in 400 kV Akal-Jodhpur Line, Rajwest unit and 500 MVA ICT 4 which tripped on E/F indication. After that the jumper touched the tower body due to heavy wind causing tripping of 400 kV Akal-Barmer Line on Zone 1 indication at Barmer end. Due to opening of breaker at Barmer end, the over voltage relay operated (443 kV) at Akal end and causing opening of breaker at Akal end. At that time only two Nos. 220 kV Lines remained available for evacuation of the generation. To avoid collapsing of the complete system about 150 MW generation of 220 kV Jajiya Line was immediately disconnected and it was requested to all wind power developers to cut down the wind generation immediately. It was also intimated by M/s Rajwest Power telephonically that one No. unit of 135 MW was also tripped at that time. Name of the tripped elements:

400kV Akal-Barmer Line 400kV Akal-Jodhpur Line 135MW unit-2 at 220kV Rajwest running at 70MW generation 500MVA ICT at Akal Station Wind Generation of Rajasthan Area

3. Due to disturbance between Akal Barmer 400KV line(open conductor) persist for long duration, unbalance in voltage occurs ,thus the negative sequence current increases at motor end & due to this the motor got tripped on unbalancing. Unbalance trip found on MV motors relays & turbine trip received on Generator protection relay. Unit-2 generating 70MW generation tripped. Station EL of the tripping of unit-2 is given below:

4. As per PMU data:

Frequency dip ~ 0.11Hz observed, indicating Generation loss-load loss ~ 600MW. No fault observed. However, voltage at Agra dipped after the tripping

5. Remedial action taken by Rajasthan: The broken jumper of the 400 kV Barmer Line was repaired and the line was charged at

11.21 Hrs. on 23-05-15 and running satisfactory. The carrier protection was also found unhealthy at the time of tripping and was attended and now it is working perfectly.

6. As per NR SoE:

7. PMU Plot & SCADA Plot:

8. Preliminary Report, DR/EL has been received from Rajasthan.

1. The disturbance was occurred due to opening of Y-phase jumper at Loc. No. 231 of 400 kV Akal-Barmer Line which was charged at 08:54hrs after erection of towers. Due to this unbalance currents flow in 400 kV Akal-Jodhpur Line tripped immediately due to setting problem (in case of VT fuse failure distance protection automatically blocked and protection shifted to definite time(time delay: 250ms) non directional over current protection but non directional earth fault protection enabled by mistake in the line, It resulted into tripping of line on unbalance current within 250ms).

Protection Committee Outcome & Recommendations:

2. Rajwest unit tripped after certain time duration due to tripping of auxiliaries of the units. 3. 500 MVA 400/220kV ICT 4 of Akal station tripped on E/F indication. After that the jumper touched

the tower body due to heavy wind causing tripping of 400 kV Akal-Barmer Line on Zone 1 indication at Barmer end. Due to opening of breaker at Barmer end, the over voltage relay operated (443 kV) at Akal end and causing opening of breaker at Akal end.

4. During the fault, wind generation of that area tripped immediately due to absence of Fault Ride Through (FRT) or Low Voltage Ride Through (LVRT) in the wind turbine. Wind generation revived within5minutes of the tripping.After tripping of ICT-4 & two 400kV lines from Akal sqeeze network available for the wind generation. Two Nos. 220 kV Lines remained available for evacuation of the generation. To avoid collapsing of the complete system again, about 150 MW generation of 220 kV Jajiya Line was immediately disconnected and it was requested to all wind power developers to cut down the wind generation immediately.

5. Protection setting of 400kV Akal-Jodhpur line has been changed. (Now, in case of VT fuse failure distance protection automatically blocked and protection shifted to definite time(time delay: 250ms) non directional over current protection)

6. Availability of time synchronized digital data to be ensured. (Action: Rajasthan; Time Frame: 15days)

7. W.r.t. the wind generation tripping of 24.06.2014, the aspect of tripping of wind generation from angle of the absence Fault Ride Through (FRT) or Low Voltage Ride Through (LVRT) has asked

from Rajasthan. No information in this regard received at RLDC. (Action: Rajasthan; Time Frame: 15days)

8. Time Synchronization of DR/EL needs to be looked into. (Action: Rajasthan; Time Frame: 15days)

9. Availability of standalone automatic downloading facility of DR/EL in the sub-station to be ensured. (Action: All the NR Constituent; Time Frame: 3months)

P. Multiple Element tripping at 220kV Salal station on 1st Jun 2015 from 21:52hrs to 23:15hrs

Event category: GD-1 Generation loss: 730MW Loss of load: 150MW

Description



Phase of the fault Y-B phase to phase fault

As per PMU data


Present Status

Remarks

Availability of Digital Data (SCADA Data) Partial

Available

DR/ EL NHPC Received After 24hrs

POWERGRID Not Received J&K Not Received

Preliminary Report NHPC Received After 24hrs

POWERGRID Not Received J&K Not Received

Detailed Report

NHPC Received POWERGRID Not Received J&K Not Received



IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; CEA (Technical standards for connectivity to the Grid) Regulation, 2007 Schedule Part-I.6 Protection Co-ordination CEA Grid standard 2010 -3.e CEA Transmission Planning Criteria

J&K

1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Protection Co-ordination 3. Delayed Fault Clearance


IEGC 5.2.r & 5.9.6.c (VI); CEA Grid Standard 15.3; CEA (Technical standards for connectivity to the Grid) Regulation, 2007 Schedule Part-I.6 Protection Co-ordination

NHPC 1. DR/EL, Preliminary report didn’t provide within 24hrs 2. Protection Co-ordination

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

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

1. Single Line Diagram of 220kV Salal station: Based on above information description of the events is:

2. In antecedent condition weather was stormy. 3. At 21:52hrs there was fault in 132kV system downward to 220kV Jammu station. Fault didn’t get

clear from Jammu end. 220kV Salal-Jammu ckt-1 & 2 tripped at the same time. At the same time unit-2&3 of Salal HEP also tripped on backup impedance protection. Fault clearance time was ~2000ms.

4. At 22:47hrs, Salal-Kishenpur ckt-3 tripped. At the same time unit-1 & 6 of Salal HEP also tripped on generator inadvertentenergization (dead machine charging) protection trip.

5. At 23:15hrs, unit-4&5 of Salal HEP tripped. At the same time 220kV Salal-Kishenpur ckt-1,2&4 also manually opened

6. Name of the tripped elements: • 220kV unit-1 to 6 of Salal HEP (115MW) • 220 KV Salal-Jammu ckt-1 & 2 • 220kV Salal-Kishenpur ckt-1,2,3&4

7. As per NHPC Report:

8. Overall SoE on behalf of details available with NRLDC:

9. After the tripping corrective action taken by NHPC:

S. No. Time (in hrs) Difference Reason Source

Power Flow in antecedent condition (in MW) Remarks

1 22:49:43.572Inadvert.Energ.prot.TRIP operated

EL of Unit-1 0

00:00:01.020

22:49:44.592Backup Impedance Protection operated

EL of Unit-1

2 21:52:08.710 EL of Unit-3 103.8200:00:00.600


EL of Unit-3

3 21:52:43.273 EL of Unit-200:00:00.637


EL of Unit-2 102.16

421:52:54.576

Tripping of 220kV Salal-Jammu ckt2

Inferred from DR details of 220kV Salal-Jammu ckt2

521:52:54.995

Tripping of 220kV Salal-Jammu ckt2

DR details from Salal end

621:57:06.092

220kV Salal-Jammu ckt1 already tripped

DR details from Salal end 0

822:47:01.478

220kV Salal-Kishenpur ckt3 tripped


922:49:12.539 220kV Salal unit-1


10 22:50:05.571 Inadvert.Energ.prot.TRIP EL of Unit-6 0

1. Point wise reply of Salal station is given below: Protection Committee Outcome & Recommendations:

2. New Siemens make relays has been installed for backup impedance protection of the unit-

1,2,3&6. Unit-4&5 have electromechanical relays. Salal unit-2&3 due to sensitive backup impedance protection. (time delay of 500ms has been changed to 1.5second) Z-1 of the backup impedance protection should be restricted upto GT(Generator Transformer) & Z-2 of the backup impedance protection should be restricted upto longest outgoing line from the plant. Time delay for

both the zone to be changed to 1.5second. Backup impedance protection started in unit-1& 6 also but didn’t trip the unit. Setting of backup impedance protection of unit-1& 6 also to be checked & corrected. (Action: NHPC; Time Frame: 7days). Unit-

3. After tripping of unit-2 & 3, manual switchover to other UAT couldn’t be possible. Station supply backup was already under off condition. All the station DC supply came on battery backup. These batteries were also very old, resulted into quick discharging and station dc supply failed. Just before the dc supply failure again fault occurred into the system voltage dip observed into the system and unit-1&6 tripped on dead machine charging protection due to immediate tripping on voltage level less than 50% of the system voltage. During tripping of unit-1&6 one pole of unit-6 didn’t open. This pole opens manually by the operator.

4. At 23:15hrs, 220kV Salal-Kishenpur ckt-1,2&4 & unit-4&5 opened manually by the shift operator due to DC supply failure in the station.

5. In second incident Setting of generator inadvertent energization protection in unit-1&6 to be changed, time delay of 2-3 second should be incorporated in case of voltage go below 50% of the system voltage. (Action: NHPC; Time Frame: 7days)

6. Old battery bank has been replaced with new lead acid battery bank. 7. Capacity test of the battery bank of maintenance free battery to be done in one year. (Action: All

the NR constituents) 8. Automatic changeover of AC supply in the sub-station to be planned & implemented. (Action:

NHPC; Time Frame: 45days) 9. DR/EL time synchronization to be looked into by NHPC.(Action: NHPC; Time Frame: 15days)

B.2 Utilities were requested to take remedial action/submit the report of the event with following link www.nrpc.gov.in/PCC/PCC30/PCC30_Event.pdf

1. Sewa –II Power Station (Agenda by NHPC)

Additional Agenda-I

Representative of NHPC stated that Third party protection audit of Heeranagar Sub Station (JKPDD) has been carried out in the month of March 2015. PDD J&K has installed numerical relays with feature of O/C & E/F only. Distance protection relays are yet to be installed. This needs to be expedited. Further implementation of observations / suggestion of protection audit team may also be expedited, so that tripping of Sewa –II power station may be reduced. In this meeting, PSC recommended to form a group comprising of members from NHPC and PDD J&K and group will submit the joint report after resolving all the above mentioned issues by 31.12.2015 to NRPC Sectt. with a copy to NRLDC.

2. Uri-II Power Station (Agenda by NHPC) Representative of NHPC stated PLCC system of Uri-Uri-II line is not commissioned and requested PGCIL to commission the system at the earliest. In this PSC meeting, POWERGRID agreed to commission the same by 31.12.2015.

Representative of NPCIL reported that Ministry of Power constituted a Task Force

Additional Agenda-II

Revision In 220 kV And 400 kV Line Relay Settings (Agenda by NPCIL)

http://www.nrpc.gov.in/PCC/PCC30/PCC30_Event.pdf�

on Power System Analysis under Contingencies as per the recommendations of CEA Enquiry Committee on grid disturbance that took place in NEW grid on 30th& 31st July, 2012. The recommendations of the above task force in respect of distance protection relay settings have subsequently been discussed in WRPC, CEA and accepted them with minor modifications.

Sr. No.

Distance Protection – Setting Parameter

Present Setting

Revised Setting Remarks

1. Zone-2 Time Delay 300 – 400 msec

350 msec 500-600 msec for a long line followed by short line

2. Zone-3 Time Delay 800-1000 msec 1000 msec 3. Zone-4 Time Delay 800-1000 msec 450 msec 4. Directional Earth

Fault Element i. Characteristic ii. Current Setting iii. Time Delay

--

DT 10 % 1500 msec

This protection is built in distance protection numerical relay.

2.0 220 kV relay settings are proposed to be revised as indicated in the table below.

Sr. No.

Setting Parameter Revised Setting

Remarks

1. Zone-2 time delay of RAPS-C - ANTA line at ANTA end.

600 msec. This is in line with CEA Task Force recommendation indicated in Clause 1.0 above.

2. Back up Directional Over current protection (67) at RAPS-C end i. Characteristic ii. Current Setting iii. Time Delay

DT 5In 450 msec

Time delay is proposed so as to coordinate with Zone-2 timings of all lines emanating from RAPS-B and also to provide margin between Zone-2 tripping time of ANTA line at Anta end

3. Back up Directional Over current protection (67N) at RAPS-C end i. Characteristic ii. Current Setting iii. Time Delay

DT 0.2In 450 msec

4. Back up Directional Over current protection (67) at RAPS-B end i. Characteristic

DT 5In 550 msec

Time delay is proposed so as to coordinate with Zone-2 timing of ANTA line at RAPS-C end.

ii. Current Setting iii. Time Delay

5. Back up Directional

Over current protection (67N) at RAPS-B end i. Characteristic ii. Current Setting iii. Time Delay

DT 0.2In 550 msec

In this meeting, PSC suggested to revise the above settings in line with the recommendations of Ramakrishna Committee (Task Force on Power System Analysis under Contingencies constituted by Ministry of Power, GoI).

Table Agenda Presentation to suggest measures for bringing improvement in the field of Power System Protection A group has been constituted to suggest measures for bringing improvement in the field of Power System Protection among the utilities in Northern Region. A presentation in this regard was made by NRPC Sectt. and the same is enclosed as Annex-V. PSC has given in-principle approval of the recommendations of the group for further approval by TCC/NRPC.

Annex-I

Name

List of Participants for the Protection Sub-Committee meeting held on 21.09.2015 at NRPC Secretariat, New Delhi

Designation Organization Phone/Mobile e-mail ID Nitin Yadav Sr. Engr NRLDC 9560050257 [email protected] Narender Sharma

S.E/NPCC HVPNL 09354194827 [email protected]

Ramanand Mishra

XEN/HVPNL HVPNL 9312712754 [email protected]

A Pathak SO/F,NAPS NPCIL

NAPS NPCIL 9412768294 [email protected]

Harish Sharma SO/C,NAPS NPCIL

NAPS NPCIL 9412768329 [email protected]

Sandeep Gupta SME(E) RAPS-C NPCIL 9413356564 [email protected] Parvesh Kumar AM(E), NHPC

Ltd. NHPC 9419912801 [email protected]

Mahesh Bajaj Manager(E) Salal power station NHPC

9419169932 [email protected]

I.P.Ranjan Sr. Mgr NHPC 9805073456 [email protected] Vijay Kumar Joshi

Mgr NHPC 9971998358 [email protected]

G.A.Babu Manager(E) NHPC 7840054755 Gugu&[email protected]

Kavindra Singh Tech. Advisor UPPTCL 94127-49803 [email protected] Amin Aziz SE(T&C) MRT UPPTCL 9412749817 [email protected] G.M.Agrawal EE (T&C) UPPTCL 8130599662 [email protected] A.K.Chander Mgr(T)

Protection IPGCL/PPCL 9717698181 [email protected]

N.C.Sharma DGM(T)Protection

IPGCL/PPCL 9717694930 [email protected]

I. S. Bajwa Addl SE/BBMB BBMB 9463998154 inderjeetbajwa Rajbir Singh ASE PSTCL 9646118223 [email protected] Ashwini Kumar

E.E(T&C) PTCUL 9412087882 [email protected]

Asim Baig AE(T&C) PTCUL 9412087885 [email protected] B.L.Yadav AGM NTPC 9650993044 [email protected] Somes Bandyopadhyay

AGM NTPC, Delhi 9650992413 [email protected]

Paritosh Joshi Manager(T) DTL 9999533933 [email protected]

Er.S.P.Janwal Sr.EE(Prot) HPSEBL 9418122067 [email protected] Hitesh Kumar Mgr(Prot) DTL 9999533669 [email protected] B.L.Gujar Mgr(Prot) I DTL 9999533985 [email protected] Noman Ahmad S.E.(T&C)Addl. UPPTCL 9415311083 [email protected] Pankaj Malviya SE(T&C)

lucknow UPPTCL 9450909474 [email protected]

P. Dhariwal XEN(Prot) RRVUNL 9414049718 [email protected]

mailto:[email protected]�







mailto:Gugu&[email protected]�

mailto:Gugu&[email protected]�










ICTPS RRVUNL

Mukesh Singhal

SE ISP,RVPNL RRVUNL 9414061406 [email protected]

M.S.Hada Manager POWERGRID


Sushil Uday Trivedi APL 9099055054 [email protected] Brijendra B.Singh

Sr. Engr. NLDC,POSOCO


Rajiv Porwal Chf Mgr NRLDC 9871581133 [email protected] Ankit Gupta Engr NRLDC 9560270520 [email protected] Sandeep Sarwate

ACE NPCIL 9809441271 [email protected]

V.H.Manohar CE(E) NPCIL 9969113084 [email protected] Sanjeev Kumar AM(T),SO Delhi SLDC 9999533917 [email protected]

m Ramneet Chanana

AM(T)Prot DTL 9999533730 [email protected]

Ajay Talegaonkar

S.E. (O) NRPC

Naresh Kumar EE(O) NRPC B.S.Meena EE(O) NRPC Ratnesh Kumar AEE(O) NRPC








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 POWERGRID is working. Likely to be completed progressively by 31.03.2016.

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 earlier

status HVPNL had made the PLCC functional. POWERGRID will confirm the same within a month to NRPC Sectt.

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 earlier

status HVPNL had made the PLCC functional. POWERGRID to confirm the same within a month.

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

-do-

10 220 kV Noonamajra-II Panels available, Pending for commissioning

-do-

PLCC issues with PSTCL

01 Ludhiana 220kV Pakhowal Installed but not working As per PSTCL PLCC is working. End to end joint testing is completed for Ludhiana but pending for Amritsar. PSPCL stated that end to end joint testing for Amritsar to be

02 Amritsar 220kV Verpal -I Not Installed 03 220kV Khasa -II Not Installed 04 220kV Verpal- II Installed but not working 05 220kV Khasa-I Installed but not working

postponed till the completion of work related to new lines for Naraingarh that will originate from Amritsar.

Annex-III

Status of Third Party Protection Audit carried out by NRPC Team of experts

Utility Third party protection audit carried out by

No. of sub-stations covered/ expected to be covered

Status of Audit

Status of Report

Status of submission of action Plan for rectification of deficiencies

RRVPNL, RRVUNL

CPRI RRVPNL-39 RRVUNL-5

Completed Submitted RRVPNL-Action initiated but Action Plan not submitted. RRVUNL- Action Plan submitted. Expected completion by December, 2015.

BBMB -do- 20 -do- Submitted Action Plan not submitted but action initiated.

PSTCL, PSPCL

-do- PSTCL-22 PSPCL-3

-do- Not submitted Action Plan not submitted.

UPRVUNL -do- 2 -do- Not submitted to NRPC though UPRVUNL received the Report.

Action Plan not submitted but rectification of defects initiated.

UPPTCL -do- 41 Yet to be completed

Shall be submitted after receipt and examination of Report, same.

Action Plan will be submitted after submission of report by CPRI.

THDCIL (Koteshwar HEP)

-do- 1 Completed Submitted Rectification of observed defects completed.

Rosa Power -do- 1 Completed Submitted Action Plan not submitted but rectification is underway.

HVPNL NRPC Team 4 Completed Submitted Action Plan for two sub-stations namely 220 kV Tepla & Bastara not submitted.

UJVNL -do- 2 Completed Submitted Action Plan not submitted.

PDD J&K -do- 3 Completed Submitted Action Plan for Heeranagar and Amargarh not submitted.

DTL -do- 4 Completed Submitted Action Plan for two sub-stations namely 220 kV Mehrauli and Rohini-I S/s not submitted.

JPL -do- 1 Completed Submitted Rectification of observation complied.

PTCUL -do- 4 Completed Submitted Action Plan for two sub-stations namely

Utility Third party protection audit carried out by

No. of sub-stations covered/ expected to be covered

Status of Audit

Status of Report

Status of submission of action Plan for rectification of deficiencies

220 kV Pantnagar (SIDCUL) & 132 kV Kashipur not yet submitted.

HPSEB Ltd., -do- 6 Completed Submitted Action Plan for 4 sub-stations namely 220 kV Giri, Uprela Nangal, Kangoo & Kotla not yet submitted. Rectification of observation partly complied.

HPGCL -do- 1 Completed Submitted Rectified of observation complied.

NPCIL -do- 1 Completed Submitted Action Completed. NHPC -do- 1 Completed Submitted By December, 2015 APCPL -do- 1 Completed Submitted Completed. UT Chandigarh

-do- 1 Completed Submitted Not submitted.

Budhil Power -do- 1 Completed Submitted Not submitted.

Annex –IV Status of Bus bar Protection for Northern Region Constituents

State/Constituent

TRANSCO/GENCO

Total No. of S/S/Switchyards(220 kV and above)

No. of substations/ switchyards where Bus bar protection is functioning

Remarks Action Plan

Delhi DTL 37 34 For 220 kV s/stns namely , Gopalpur and Kanjhawala is being planned.(Lddi Road is GSS)

25 nos. new BBP is being procured. Under Approval Stage. Tender will be floated for 08 no. by 31.10.2015.

Haryana HVPNL 61 30 On 20 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 commissioned progressively by 31.12.2016

HPGCL 03 03 Rajasthan RVPNL 95 23+(6defectiv

e) 80 nos under procurement.10

received commissioned by 31.12.2015

RVUNL 05 05 Himachal Pradesh

HPSEB 08 05 At one s/s it is working, 2 sub-station it is defective.

02 no will be commissioned by this year end and rest by March, 2016.

Punjab PSTCL 89+(4 no 400 kV s/s)

39+(4 no 400 kV s/s)

For 07 nos. Commissioning is in progress, will be completed by December, 2015. For remaining tendering process underway.

PSPCL 03 03 J&K PDD 06 - Uttarakhand PTCUL 10 09

UJVNL - - BBMB BBMB 23 20 Not required at

Dhulkote and Jagadhari. also for Sangrur, Kurukshetra and Delhi as no. of feeders is less than five. PSC decided that it needs to be installed.BBMB will come up with agenda to deliberate

For Sangrur Process is initiated. Commission by December, 2015.For Barnala it is to be provided by PSTCL as agreed in PSC.PSTCL will commission it by 31.12..2016

this issue.

Uttar Pradesh UPPTCL 82 10 21 nos. received and commissioning is in progress, will be completed by June 2015f procurement stage.

For the remaining stationed procurement action has been initiated.

UVUNL 05 - POWERGRID PGCIL 55 55 Central Generating Stations

NTPC 11 11 NHPC 09 09 NPCIL 02 02 THDC 02 02 SJVNL 02 02

northern regional electricity board

Documents