SOUTHERN REGIONAL POWER COMMITTEE BENGALURU

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4 SOUTHERN REGIONAL POWER COMMITTEE BENGALURU Agenda for the 62 nd Meeting of Protection Coordination Sub-Committee of SRPC to be held on 15 th March, 2017 (Wednesday) 1. Introduction 2. Confirmation of Minutes of last PCSC meeting Confirmation of minutes of 61 st Protection Coordination Sub-Committee meeting held on Grid Occurrences 3.1 Grid Disturbance (GD), Grid Incidences (GI), and trippings due to failure of Auto-reclosing (A/R), and mal-operation of PLCC equipment that occurred during the period January - February, 2017 given at Annexure-I would be discussed in the PCSC meeting. Constituents are requested to furnish the following information in respect of the above grid occurrences to have fruitful discussions in the PCSC forum. (a) Single line diagram of the station with switching devices, CT, PT and relay details. (b) Cause of the tripping & Remedial Action taken (c) Relay setting details Constituents are requested to bring/ give full particulars of the tripping events pertaining to their system. 3.2 In compliance of Regulations 5.2 (r) of IEGC, the Constituents are required to furnish the following information in respect of Grid Occurrences that occurred during December, 2016: (a) First Information Report (FIR) (b) Event Logger (EL) output (c) Disturbance Recorder (DR) output (d) Trip event analysis report (with pre and post fault system conditions) Non-furnishing of tripping details (FIR/DR/EL/TR) for the period had been brought to Constituents notice vide SRPC letters (i) No. SRPC/ SE-III/ PCSC-61/ 2017/ dated and (ii) No. SRPC/ SE-III/ PCSC-62/ 2017/ dated and (iii) No. SRPC/ SE-III/ PCSC-62/ 2017/ dated Non-compliance in this regard would be discussed in the meeting. 4. Submission of Reports/Compliance by Constituents 4.1 Status of pending Protection Coordination Sub-Committee (PCSC) Recommendations Status of the pending PCSC recommendations (up to 61 st PCSC meeting) given at may please be sent latest by Agenda for the 62 nd Meeting of PCSC scheduled to be held on 15 th March, 2017 Page 1

5 4.2 Remedial measures for "Transmission Elements under Forced Outage" The Constituents are requested to send the remedial measures/ action taken by them for the tripping events as circulated vide our s. (I) The trip events are based on the daily reports at SRLDC website DailyReport.aspx under the menu: Reports->Daily-> "TL under Forced Outage") 4.3 Certificate for Healthiness of Batteries As per the MoP direction given in pursuant to recommendations of the Enquiry Committee (NEW grid disturbance on 30 th & 31 st July, 2012), RPC s are required to obtain from their respective Constituents the monthly certificate for healthiness of batteries, installed at 220 KV and above voltage level Substations (for power supply to Relays, RTUs and PLCC equipment) and furnish the same to CEA/ MoP. With reference to above, the Constituents have been requested to submit the certificate on healthiness of batteries on monthly basis (i.e. status for a month shall be sent by the 7 th day of the following month) to SRPC. The sought status for the month of January, 2017 is awaited from the following SR-Constituents: TSGENCO (Hydro), KPTCL, TANGEDCO, PED, NTPC (Ramagundam) & NLCIL 5. Auto-Reclosure Implementation on all 220 kv & above transmission lines of Southern Region Majority of the faults that occur on transmission lines are of transient nature; hence provision of Auto-Reclosure certainly helps not only in preventing forced outage of the subject transmission line, but also in averting cascade trippings, in some cases, of adjacent transmission lines due to consequent over-loading. The provision for Auto-Reclosure is also mandated by Regulation 43 (4) (c) of CEA Technical Standards for Construction of Electrical Plants and Electric Lines, 2010, which has force of law. Therefore, it is in the interest of grid security that all Constituents implement auto-reclosure feature on all 220 kv & above transmission lines in their respective control areas. Any exceptions to this needed to be properly justified. The issue was discussed in previous PCSC meetings where logics to be used for implementing A/R were clarified as follows: Normal single-shot, single-ph A/R scheme (with simultaneous opening at both ends of feeder with a dead-time of 1 sec and reclaim-time of 25 sec) Time-Differentiated A/R scheme [suitable for stations having concerns on closing on to un-cleared fault, esp. Generators (Coal/ Gas/ Nuclear/ Hydro)]: In this, after a line has been opened from both ends (generator end & grid end) on A/R operation, the grid end will be auto-reclosed as usual after the elapse of its dead-time (say, 1 sec). However, the generator end relay will check for the line voltage after elapse of an elongated dead time (say 1.3 or 1.5 sec; here the additional 0.3 or 0.5 sec has been included as a safety time margin; and this time shall be less than PDR time delay). If the line voltage so sensed is healthy & normal (which implies that the fault has already been cleared), then generator end will be auto-reclosed; else 3-ph trip will be given at generator end to open the other two phase poles. Agenda for the 62 nd Meeting of PCSC scheduled to be held on 15 th March, 2017 Page 2

6 It was also clarified that A/R implementation on lines connecting two generating stations is optional. In this regard, the status of implementation of A/R (excluding Radial feeders & Cables) as furnished by SR-Constituents is as follows: Sl. No. Name of the Constituent 220 kv 400 kv 765 kv Total no. of lines No. of lines where A/R is in service Total no. of lines No. of lines where A/R is in service Total no. of lines No. of lines where A/R is in service 1 APGENCO 44 Nil Auto-Reclose scheme for all 220 kv feeders of RTPP, Lower Sileru, Upper Sileru, Donkarayi & Srisailam RBPH of APGENCO are available but not commissioned since inception. Dr. NTTPS (VTPS) 220 KV -- Auto-Reclose scheme for 9 feeders out of 15 feeders are available, but not commissioned since inception. For remaining 6 feeders, Static relays have to be replaced with Numerical relays to facilitate Auto-Reclose. 2 APTRANSCO Details are being collected Implemented in all existing 400 kv lines (Details not provided) 3 TSGENCO (Hydro) Nil 5 Nil TSGENCO 16 Nil (Thermal) 4 TSTRANSCO A/R is implemented in 1 no. of 220 kv Tandur Sedam line. For remaining lines, data is being collected Implemented in all existing 400 kv lines (Details not provided) 5 KPCL KPTCL TANGEDCO & TANTRANSCO 8 KSEB PED PGCIL (SR-I) PGCIL (SR-II) NTPC NTPC-Simhadri NTPC-Kudgi NTPC- Ramagundam 4 Nil (only for main breakers) NTPC Agenda for the 62 nd Meeting of PCSC scheduled to be held on 15 th March, 2017 Page 3

7 13 NPCIL Kayamkulam MAPS 4 Nil KGS 2 Nil A/R on 220 kv lines has not been kept in service as the remote ends are connected to hydro power stations. KKNPP 2 Nil BHAVINI 4 Nil NLC JSWEL 2 Nil UPCL 2 Nil NTECL-Vallur * Even though A/R has been implemented in all the six 400 kv lines, due to fibre optic cable related issues between Vallur and NCTPS-II, A/R is effectively in service for 4 lines. 18 TPCIL CEPL HNPCL IL&FS Lanco KPL 2 Nil As the distance between Kondapally and VTPS Stage IV is only one span (350 mtrs), A/R has been kept blocked from both the ends. 23 NTPL MEPL As the tie-line, 400 kv MEPL SEL line, is a short line, A/R has not been kept in service on this line. 25 SEL Action plan furnished by SR-Constituents for implementing A/R on the transmission lines, where it is presently not in service. Sl. No. Constituent Action plan for implementing A/R 1 APTRANSCO A/R scheme is implemented in all 400 kv network, and also for the latest & upcoming future 220 kv & above lines in APTRANSCO. The status of availability and functioning of A/R scheme on the existing 220 kv network is being obtained from the field. 2 TSTRANSCO For all the upcoming 220 kv & above feeders, the concerned wings have been requested to ensure A/R function and its implementation in the field. With regard to implementation of A/R function for intra-state 220 kv feeders, the field data is being sought regarding its feasibility for its implementation. After receipt of complete field information, the same will be compiled and decision will be Agenda for the 62 nd Meeting of PCSC scheduled to be held on 15 th March, 2017 Page 4

8 taken by the Management. 3 KPCL In Sharavathy Generating Station, Auto re-close feature will be enabled after heightening the Towers of ST- 3 and S - 2 Line. In Raichur Thermal Power Station, for 220kV lines, auto reclose feature is kept ready but disabled as per KPTCL guidelines. In Nagjhari, Carrier aided protection wiring is in progress. The Auto re-close function will be enabled after completion of the Carrier aided protection wiring in consultation with KPTCL, RT Division. In Kadra, Auto re-close feature is Kept ready. However, the same is enabled in consultation with KPTCL, RT Division. In Kodasalli, Auto re-close feature is Kept ready. However, the same is disabled, since Lines are running between Power Houses. 4 KPTCL W.r.t. existing 400 kv lines, A/R has been implemented on all lines. W.r.t. existing 220 kv lines, retrofitting of Main-2 distance scheme in place of back up OC and EF relays in protection of 220kV lines is being taken up under R&U project, and awarded to M/s GE T&D India Limited. Along with Main-2 retrofitting works, Auto Reclosure scheme implementation will also be carried out for existing 220 kv lines. Works at 26 No.s of audited sub stations are taken up on top priority and planned to complete before Further, A/R will be implemented in all future 400 kv & 220 kv lines. 5 TANGEDCO & TANTRANSCO Details of 230kV Feeders in which A/R not enabled: 1. A/R not enabled in the following feeders for the reasons stated: Generation connected 76 feeders Radial feeders 4 Cable feeders 6 Total A/R to be provided in the following feeders: Breaker problem Communication network to be provided Total 15 4 Breaker procurement is under progress and will be replaced with in one year. 11 due to non availability of Communication network and will be completed within 6 months. Agenda for the 62 nd Meeting of PCSC scheduled to be held on 15 th March, 2017 Page 5

9 6 KSEB Details of 220 kv feeders where A/R was not implemented are as follows: Sl. Feeder Name Status of A/R Remarks No. facility kv Kozhikode-PG Short lines; so not provided Areacode line kv Kozhikode-PG Areacode line kv Kozhikode-PG Areacode line kv Shornur Areakode NIL Communication link not available between Shornur and Areakode kv Idukki Lower Periyar 3-phase Now switched-off, and kept line 1 under observation. Will be implemented at the end of January 2 nd Week kv Idukki Kalamassery line kv Idukki Kalamassery line-2 1-phase Not enabled A/R relay at Idukki end faulty. Planning to change 3-ph at both ends at the end of Feb, kv Brahmapuram Not enabled Due to dangerous condition of Cochin line-1 multi-ckt tower auto-reclosing kv Brahmapuram Not enabled facility was kept in switched off 10 Cochin line kv Cochin Kalamassery Not enabled condition. Will be enabled after completing the rectification work. line kv Cochin Kalamassery line-2 Not enabled kv New Pallom Pallom line 7 NPCIL (Kudankulam NPP) Very short line; Pilot wire protection implemented, auto-reclosing facility not provided. As agreed in SRPC meetings, A/R has not been kept in service from KKNPP end on 400 kv KKNPP Madurai line. Presently, A/R has not been kept in service on the TTPS bound 230 kv line as TTPS is a generating station. The matter of providing A/R on SRPudur bound 230 kv line has been taken up taken up with NPCIL Management, and the action plan for implementing the same will be furnished in PCSC-62 meeting scheduled to be held on NPCIL (MAPS) A/R on all four 230 kv lines would be put into service by July, UPCL The AR in 220 kv Lines at UPCL end are already configured and scheme is ready. On completion of AR readiness at opposite end (Kemar) the AR can be put in service. 9 JSWEL Though A/R functionality is available at JSWE on both 220 kv JSWEL Lingapur lines, the same has not been kept in service due to (i) nonprovision of the same from Lingapur end, and (ii) carrier protection issues. Agenda for the 62 nd Meeting of PCSC scheduled to be held on 15 th March, 2017 Page 6

10 The following Constituents have not furnished the Action Plan for implementing Auto- Reclosure in their 220 kv & above voltage level transmission lines: APGENCO, APTRANSCO, TSGENCO, TSTRANSCO, NLCIL, NTPC-Ramagundam, BHAVINI The issue was also discussed in TCC-30 & SRPC-31 meetings held on February, 2017, and all above Constituents agreed to furnish the detailed Action Plan for implementing A/R in their 220 kv & above voltage level transmission lines by next PCSC-62 meeting scheduled to be held on It was noted that issues relating to philosophical changes, PLCC communication, and breakers supportability as the main reasons for non-implementing A/R. In this regard, all SR-Constituents who have not implemented A/R owing to the stated reasons are requested to kindly address them favorably, and take steps to implement A/R in their respective networks in phased manner at the earliest. 6. Non-operation of SPS for Kudankulam NPP (KKNPP) Unit-2 on The following SPS, finalized in the 56 th meeting of PCSC held on , has been put into service by NPCIL to deal with the contingency of tripping of Units at KKNPP: SPS for the Contingency of Tripping of Units at Kudankulam NPP Contingency Action Case-1: Unit-I Trips & Trip Signal-1 to be sent via Kolar to shed loads in Tamilnadu, Karnataka, Kerala, AP & Telangana. Generation loss (P) > 500 MW Case-2: Unit-II Trips & Generation loss (P) > 500 MW Trip Signals - 2 to be sent via Kolar to shed loads in Tamilnadu, Karnataka, Kerala, AP, Telangana & Puducherry. However, it was observed that the SPS had not operated during ramping down of Unit-II on When enquired, KKNPP vide their dated informed that the conditions for SPS operation had not been satisfied during the said event as the generation loss/ drop from 975 MW to 586 MW took almost 2 minutes, and generation loss/ drop from 598 MW to 97 MW took almost 8 sec. Agenda for the 62 nd Meeting of PCSC scheduled to be held on 15 th March, 2017 Page 7

11 In this regard, it is proposed to deliberate on the sufficiency of the time-window adopted for calculating generation loss with focus on power flows/ line loadings on SR-WR and SR-ER transmission links. NPCIL (KKNPP) is requested to present their views on the issue. 7. Other Protection Issues, if any, with the permission of the Chair 8. Sending Agenda items for the PCSC meetings As per the Guidelines of CEA/MOP, it has been decided to conduct the PCSC meetings on monthly basis. It is requested that Agenda Items for the PCSC meetings, if any, may please be sent latest by 5 th working day of the month to SRPC Secretariat to compile and circulate the same so as to have fruitful discussions in the PCSC meetings. 9. Date of next PCSC meeting The 63 rd PCSC meeting would be conducted on (Wednesday) from 10:30 hrs in the Conference Hall of SRPC Secretariat, Bengaluru. ***** Agenda for the 62 nd Meeting of PCSC scheduled to be held on 15 th March, 2017 Page 8

12 Grid Occurrences Annexure-I For all tripping events involving failure of substation equipment, Constituents are requested to kindly furnish the SLD or equivalent pictorial representation showing (i) Location of the fault, and (ii) Bus-bar arrangement/ Configuration of feeders and other connected equipment with proper CB positions (OPEN/ CLOSE) at the time of occurrence of the fault. I. Details of Grid Disturbances: Sl.No. Details of Event Date & Time Reason Remarks Category 1 Complete outage of 220kV Nagjheri substation of KPCL at 00:38 hrs Both buses of 220kV Nagjeri power station of KPCL got deenergized GD-1 2 Complete outage of 400/230kV Karamadai substation of TANTRANSCO at 2:17 hrs Triggering incident wad failure of B-phase CT of 230 kv Karamadai PUSHEP line GD-1 II. Details of Grid Incidents: Sl.No. Details of Event Date & Time Reason Category 1 Tripping of 400kV Gazuwaka-Vemagiri (PG) line and 400kV Vemagiri(PG)-Nunna line at 13:05 hrs For 400 kv Gazuwaka-Vemagiri (PG) line, direct trip was received at Gazuwaka after 250ms of occurrence of fault and fault was persistent for 250ms. Over-voltage stage-1 instantaneously operated in 400kV Vemagiri(PG)-Nunna line during fault in 400 kv Vemagiri(PG) - Gazuwaka line. 2 Tripping of 400 kv Madurai-Karaikudi line at 1:55 hrs Line got tripped on operation of overvoltage stage-1 protection. R, Y & B-phase voltages recorded in DR were 247kV, 240kV & 254kV (Phase to earth). The B-phase voltage was found to have 14KkV & 7KV difference when compared to Y and R phases. 3 Tripping of 220kV Bus 2 and connected elements (220kV HAL #1 and 2, 400/220kV ICT- 1, 2 and 220/66kV ICT-2) at 400/220kV Hoody substation of KPTCL (Load loss : 590 MW) at 23:06 hrs Failure of R-phase CT of 220/ 66 kv transformer-2 at 220kV Hoody end resulted in a bus fault in 220kV Bus-2. Fault was cleared by backup protection of ICT's (220kV lines were being radially operated) due to absence of/ faulty busbar protection. GI-1 Page 1 of 4

13 Annexure-I 4 Tripping of 400 kv Gazuwaka-Vemagiri (PG) line and 400kV Vemagiri(PG)-Nunna line at 22:03 hrs 400 kv Gazuwaka-Vemagiri (PG) line and 400 kv Vemagiri(PG)-Nunna line got tripped due to direct trip receive at Gazuwaka and Vijayawada respectively 5 Tripping of 220kV South Bus and connected elements (220kV HSR, 220kV Nagnathpura, 220 kv Harohalli, 220 kv Subramanyapura, 220 kv Tataguni, 220 kv Mallur and 400/220kV ICT-1, 2 and 3) at 400/220kV Somanhalli substation of KPTCL (Load loss : 1000 MW) at 14:34 hrs Triggering incident was fault in in 66kV Somanahalli Bannerghatta line and fault was cleared by operation of Back-up OCR at Somanahalli end. GI-1 6 Tripping of 400kV Trichy- Karaikudi line at 21:45 hrs line tripped on operation of over voltage protection at Karaikudi end and direct trip was received at Trichy. Voltage recorded in DR in antecedent conditions were kv, kv, kv respectively 7 8 Tripping of running Units & 230kV feeders at Tuticorin TPS of TANGEDCO (Gen Loss: 640 MW) Tripping of 400/220 kv Guttur ICT at 22:36 hrs at 13:26 hrs Failure of Bus section-i Y phase CT resulted in operation of bus-bar protection. Running Units#1, 4 and 5, 230kV Kayathay, 230kV Kudankulam, 230kV Sterlite, Station transformer-1, 2&3 got tripped during the incident. Unit-2&3 were not in service. ICT got tripped during fault in 400kV Kaiga Guttur line-1 GI-1 9 Tripping of 400kV Kaiga- Guttur line-1 & 400/220 kv ICT-1 at Kaiga at 7:29 hrs Spurious operation of LBB protection at Kaiga end 10 Tripping of 400 kv Guttur- Hiryur line at 8:36 hrs line tripped due to operation of reactor Buchholz trip at Guttur end 11 Tripping of 400 kv Guttur- JSW line at 13:40 hrs Line tripped on R-B-N, zone-1 at Guttur end and Zone-3 at JSW end. Fault current observed for 800ms in DR of JSW 12 Tripping of 400 kv Narendra-Guttur line at 18:00 hrs Line tripped on operation of over voltage stage-1 protection at Guttur. DR and EL not furnished to validate the tripping. 13 Tripping of 220 kv Regulapadu - Alipura line at 12:17 hrs 220kV Regulapadu-Alipura feeder Tripped at Alipura and was holding from Regulapadu 14 Tripping of 765 kv Angul- Srikakulam line-1& at 15:30 hrs Line-1 tripped on B-N fault. Line did not auto-reclose and CB tripped on Polediscrepancy. Line-2 also got tripped on Zone-1 trip. Page 2 of 4

14 Annexure-I 15 Tripping of 400 kv Bus-2 at 765kV Srikakulam (PG) at 12:17 hrs Suspected mal-operation of LBB operation resulted in tripping of Bus-2 III. Details of Trippings due to failure or non-operation of Auto-Reclosure Sl. No. Element Date & Time Reason Category 1 Tripping of 400 kv Vijayawada-Nellore line at 13:13 hrs Line tripped on B-phase to earth fault. At Nellore end, auto reclose attempted but unsuccessful due to persistent fault. At Vijayawada auto-reclose attempt could not be verified with the submitted DR. 2 Tripping of 400 kv Kaiga- Guttur line at 05:01 hrs B-phase to earth fault. Line did not autreclose at Kaiga end. 3 Tripping of 400 kv Kaiga- Guttur line at 12:15 hrs B-phase to earth fault. Line did not autoreclose. Delayed clearance of fault observed i.e. in 350ms. 4 Tripping of 400 kv Satenapalli-Srisailam line at 06:48 hrs R-ph to earth fault. Line did not autoreclose at Srisailam end. IV. Details of Trippings due to PLCC mal-operation Sl.No. Element Date & Time Reason Category 1 Tripping of 400 kv Malkaram - Hyderabad line at 10:07 hrs Line tripped at Malkaram end and only and was holding from Hyderabad. Direct trip was received at Malkaram 2 Tripping of 400 kv Kaiga- Guttur line at 4:05 hrs Line tripped on Direct Trip receive at Kaiga end. 3 Tripping of 400 kv Tirunelveli-Kudankulam line at 14:26 hrs Line tripped at Kudankulam end only. 4 Tripping of 400 kv Neelamangala-Hoody line at 13:44 hrs Line tripped at Hoody end on direct trip receive and was holding from Neelamangala end. 5 Tripping of 400 kv Gajwel- Bhoopalapalli line at 15:00 hrs Line tripped at Bhoopalapally on DT receive and was holding from Gajwel 6 Tripping of 400 kv Gazuwaka-Vemagiri(PG) line at 11:51 hrs Line tripped at Vemagiri(PG) end on operation of gas compartment protection trip. Line was holding from Gajuwaka. 7 Tripping of 400 kv Cudappah-Chitoor and 400 kv Krishnapatnam- Chitoor line at 16:47 hrs Page 3 of 4 Both lines got tripped due to Direct Trip receive from Chitoor end. Both lines were holding from Cudappah and Krishnapatnam.

15 Annexure-I 8 Tripping of 400 kv Vijayawada-Vemagiri line at 17:25 hrs Line tripped at Vemagiri end only and was holding from Vijayawada kv Kudgi(PG) - Kudgi(NTPC) at 18:35 hrs Direct trip received at Kudgi(PG) end. 10 Tripping of 400 kv Neelamangala-Hoody line at 5:33 hrs Line tripped at Hoody end on direct trip receive and was holding from Neelamangala end. 11 Tripping of 765 kv Kurnool- NPS line at 15:58 hrs Line tripped at Kurnool end only and was holding from NPS V. Tripping of 400 kv lines in North Chennai/ Vallur TPS complex Sl.No. Element Date & Time Reason Category 1 2 Tripping of 400kV Vallur- Kalivandapattu line-2 Tripping of 400kV NCTPS- Vallur line at 4:55 hrs Line tripped due to failure of R phase jumper. Two faults observed from DR. 2 nd fault cleared in 500ms from Kalivandapattu end at 06:01 hrs R-phase to earth fault. Zone-1 trip 3 4 Tripping of 400kV NCTPS- S.V.Chatram line-2 Tripping of 400kV NCTPS- Alamathy line at 06:16 hrs at 6:38 hrs R-phase to earth fault due to de-capping of insulator. Auto-reclose attempt was unsuccessful. R-phase to earth fault occurred in line. Auto-reclose attempt was unsuccessful. 5 Tripping of 400kV NCTPS- SVChatram line at 6:53 hrs B-phase to earth fault occurred in line. Auto-reclose attempt was unsuccessful. TANTRANSCO and PGCIL (SR-II) are requested to furnish the status of Insulators replacement for the above lines. ***** Page 4 of 4

16 Implementation of PCSC Recommendations (up to 61st Meeting) Meeting No / Index Details of Event Date & Time Reason PCSC Recommendations Utility responsible for Implementation Status of Recommendations as on Remarks Andhra Pradesh 52/I/2 (GD) Complete outage of 220kV Yerraguntla substation and tripping of running Units at Rayalaseema TPS at 10:39 hrs HV B-Ph Current transformer of 100MVA Power Transformer -1 failed resulting into a bus fault on 220KV Bus-1. Unit-1 and Unit-5 at RYTPS tripped during the fault at Yerraguntla substation 1. APGENCO to check associated logic for lube oil pump for correct operation under transient low voltage conditions at Rayalaseema TPS, Unit APGENCO to keep appropriate time delay/ fault ride through delay (typically 2 sec) in VFD speed sensor relay at all its generating Units including Rayalaseema TPS Units. APGENCO Mail received on : 1.The drop out relays of reducer oil pumps time setting was increased for all mills.so there will not be any trip under transient low voltage condition.-- --Complied 2.The recommendation regarding 2 sec time delay will be implemented during unit shut down and will be intimated immediately after implementation /II/9 Tripping of 400 kv Nellore (PG) at NPS line-1, 400 kv 19:05 hrs Krishnapatnam-Nellore (AP) lines -1&2 and 400kV NPS - MEPL line Triggering incident was snapping of Y phase conductor in 400kV Nellore (PG) - NPS line-1. Distance relay at Krishnapatnam end overreached in Zone-1, and resulted in tripping of 400kV Krishnapatnam Nellore (AP) lines - 1&2 from Krishnapatnam end. Distance relay at MEPL over-reached and resulted in tripping of MEPL-NPS line from MEPL end. APGENCO to furnish a report on the remedial action implemented w.r.t. overreaching of Krishnapatnam end distance relays during the tripping of 400 kv Nellore (PG) - NPS line-1 APGENCO Yet to be informed 42/II/3 Outage at Regulapadu station of APTRANSCO at 00:49 hrs Y-Ph Metering PT failed at 220KV Ragulapadu Substation. Fault got cleared by tripping of lines from remote ends. 1. APTRANSCO to furnish the remedial measures taken in consequent to the tripping incident along with the status of bus bar protection and bus coupler at Regulapadu S/s. 2. A/R feature to be enabled on Regulapadu Alipuira 220 kv interstate line. APTRANSCO Mail received on : 1)Failed metering PT was replaced with new PT. 2) 220kV Ragulapadu is a single bus system. Hence there is no provision for bus coupler at Ragulapadu SS. Mail received on : APTRANSCO Vide Ltr. Dt. 23/06/2015, requested KPTCL to furnish the details of available tele protection equipments and details of the equipments going to be procure for enabling the carrier aided protection on 220KV Ragulapadu-Alipura line. Based on the KPTCL information we will take further necessary action. Mail recieved on : APTRANSCOhas planned to commission ABB make ETL-41 type PLCC terminal along with NSD-50 type protection coupler at Ragulapadu end towards Alipura. vide our Ltr Dt , it is requested KPTCL to arrange ABB make ETL-41 cabinet with NSD-50 type protection coupler for establishing PLC communication between Alipura- Ragulapadu. KPTCL Mail recieved on : KPTCL is ready with ETL-41 cabinet with NSD-50 type protection coupler at Alipur end. APTRANSCO mail received on : Protection coupler equipment is ready at Ragulapadu end. Wave trap errection is pending at Ragulapadu end. To maintain the ground clearenace structural modification works are going on for errection of wave trap. APTRANSCO mail dated on : Protection coupler equipment is ready at Ragulapadu end. Wave trap errection works are going on. APTRANSCO mail dated on : Work is under progress. A/R feature will be enabled soon. APTRANSCO mail dated on : AR feature will be enabled without AR feature as wavetrap erection is under progress. Page 1 of 31

17 56/II/13 Tripping at 220kV Gooty Substation of APTRANSCO at 16:04 hrs LBB protection got operated for 400/220kV ICT-2 breaker which had resulted in tripping of 220kV Bus-2 at 220kV Gooty Substation 1.APTRANSCO to check the healthiness of the connecting cable APTRANSCO between Gooty (PGCIL) and Gooty (APTRANSCO), and replace it, if required. 2.APTRANSCO to ensure that the distributed architecture employed in implementing busbar protection at their Gooty 220 kv SS does not introduce any unwarranted delays in transmitting the triggering signals to the Central Unit. APTRANSCO mail dated on : To avoid the unwanted malopeartions due to the external LBB trip initiation from PGCIL, Vide letter Dt: , APTRANSCO has requsted the PGCIL to arrange the Master trip relay and breaker contacts of ICT-1 &2 LV side to enable the internal LBB feature in the Busbar protection scheme at 220kV Gooty Switching station. Waiting for the PGCIL response. APTRANSCO mail dated on : To avoid the unwanted maloperations due to the external LBB trip initiation from PGCIL, vide letter Dt: , ARTRANSCO has requested the PGCIL to arrange the Master trip relay and breaker contacts of ICT-1&2 LV side to enable the internal LBB feature in the Busbar protection scheme at 220kV Gooty Switching station. Waiting for the PGCIL response. APTRANSCO mail dated on : Waiting for the PGCIL response. 58/I/8 (GD) Tripping of 220 kv lines and ICT s at 220kV Chinkampalli substation of APTRANSCO at 3:15 hrs Failure of B-phase CT had occurred in 220 kv Chinakampalli - Kalikiri feeder at Chinakampalli end. (i) APTRANSCO to furnish Equipment failure Report on the CT failure to PSE&TD division of CEA with a copy marked to SRPC. (ii) APTRANSCO to provide GPS time synchronization facility at their 220/ 132 kv Chinakampally SS. APTRANSCO APTRANSCO mail dated on : 1. Equipment failure report was furnished to CEA by CE/Transmission/APTRANSCO vide letter no: 662, Dt: Completed 2. GPS panels are drawn. The associated equipment is under procurement APTRANSCO mail dated on : Associated equipment Procured.Work under progress 61/IV/3 Tripping of 400 kv Vijayawada- Vemagiri line at 21:52 hrs & at 10:52 hrs Line tripped on operation of over-voltage protection at Vemagiri end and Direct Trip was received at Vijayawada. APTRANSCO to make DR & EL functional from Vijayawada end for the line 400 kv Vijayawada Vemagiri. APTRANSCO Yet to be informed 55/II/21 Multiple tripping at Vijayawada TPS (Gen Loss : 750 MW) at 00:41 hrs Triggering incident was R-phase to earth fault in 220 kv Vijayawada TPS - Podili line. Breaker at Vijayawada TPS end was under lockout and this resulted in operation of LBB protection and further leading to tripping of 220 kv Bus-1 at Vijayawada TPS 1.APGENCO to ensure full-fledged redundancy of supply to the auxiliaries of all Units in the to-be-reviewed LT arrangement by (i) ensuring that each Unit s auxiliaries are fed from two Station Transformers connected to different buses, or (ii) any other better design. 2.APGENCO to keep LBB time setting as 200 msec at their Vijayawada TPS. 3.APTRANSCO to take steps to provide PLCC carrier communication & Auto-reclosure facility between VTPS and Podili SS. APGENCO/ APTRANSCO APTRANSCO mail dated on & : PLCC carrier aided protection wasprovided.----completed A/R feature ---- APTRANSCO mail dated on : At Podili on VTS feeder the old CGL make penumatic operated breaker is to be replaced with new one. Telangana 58 Provision of line differential protection for Jurala line 1 & 2 (line length-1.45 KM) feeders at 220 kv Jurala HPS [Carry-Over from Protection Audit Recommendations] TSGENCO The issue was discussed in PCSC-58 meeting held on , when PCSC forum agreed to de-link the implementation of the Item from the scope of Protection Audit Recommendations (PAR), and pursue it as part of PCSC Recommendations. Page 2 of 31

18 61/III/5 Tripping of 400 kv Khammam - KTPS line at 10:52 hrs Line tripped on B-phase to earth fault. First fault was persistent for 380 ms. Auto-reclose was successful at Khammam end during 1st fault. 2nd fault occurred during re-claim time of breaker hence Khammam end breakers also got tripped. 1. TSGENCO to implement the SRPC agreed philosophy for Power Swing Blocking in all distance relays on the feeders emanating from KTPS. 2. For the line under consideration, TSGENCO to consult relays OEM to migrate to new versions of Firmware (from to ) and Pset (to ). TSGENCO Yet to be informed Page 3 of 31

19 48/II/5 Tripping of 400kV Nagarjunsagar at Mahboobnagar line 2:58 hrs Line tripped on operation of over-voltage protection at Mahboobnagar and direct trip received at N sagar station. DT receive was observed in DR and EL of N sagar station. D.R/EL of Mahboobnagar was not furnished to validate the overvoltage tripping TSTRANSCO to furnish a detailed report on the tripping event along with remedial measures taken to PCSC forum. TSTRANSCO TSTRANSCO mail dated on : Due to employee bifurcation process and consequent relieving of engineers, the data could not be given. However the data for the subsequent disturbances are being communicated regularly. 59/II/3 Multiple trippings at 220 kv at 220 kv feeders and ICT s connected to Bus-1 1.TSTRANSCO make DR s & EL s functional on all feeders distance TSTRANSCO TSTRANSCO mail dated on : Ghanapur substation 19:10 hrs at 220 kv Ghanapur Station tripped on operation of Bus-bar protection during fault in 220 kv Ghanapur - Chandrayangutta lines 1&2 protection and busbar protection at their 220 kv Ghanapur SS. 2.TSTRANSCO to modify A/R Block logic such it gets blocked not on account of mere Z2/ Z3 pick-up, but only when Z2/ Z3 protection issues trip command at their 400 kv Mamidipalli SS for all feeders. 3.TSTRANSCO to spare one potential-free contact to PGCIL (SR-II) for triggering DR/EL of 400/ 220 kv ICT s at their 400 kv Ghanapur SS. 1. DRs and ELs are already functional and also submitted in the 59th PCSC Meeting. 2. A/R Block logic is been modified /IV/3 Tripping of 400 kv Gaiwel- Hyderabad line at 12:16 hrs line tripped on direct trip receive at Gajwel and was holding from Hyderabad For the line under consideration, the following shall be carried out by TSTRANSCO in coordination with PGCIL (SR-I): (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. TSTRANSCO TSTRANSCO mail dated on : (i) Letter is been given to field for conducting end to end testing of 400kV Gajwel-Ghanapur line. (ii) Healthiness of PLCC system components will be checked while conducting end to end testing. Page 4 of 31

20 Karnataka 30/I/A RTPS Tripping incidents and the Mar-14 Spl meeting held at RTPS on 13th and 14th March 2014 Spl meeting held at RTPS on 13 th and 14 th March 2014 The PCSC forum recommended for replacement of existing electromechanical relays with Numerical relays. KPCL Mail recieved on : 1. e- Tender folated for the retrofit of existing static relays with Numerical version for lines M.nagar,M.bad,ICT-1 & 2 -Technical Bid & Price bid opened. Bid evaluation and approval to place P.O. is in progress. 2. Retrofit of existing bus bar (CAG-34) with numerical version - Budgetetory offers obtained and is in process. 3. Order placed on M/s Siemens to replace relays. The work will be completed by May Mail recieved on : 1. Retrofit of existing static relays with Numerical version for lines M.nagar, M.bad and ICT- 1 & 2 -- Inspection of the Numerical relays at M/s Siemens works completed on and Dispatch clearance has been issued. Materials received. 2. Retrofit of existing bus bar (CAG-34) with numerical version Budgetary offers obtained and is under process. Mail recieved on : 1. Replacement of Old electromagnetic relays with Numerical relays has been completed for RTPS-BTPS line & commissioned on Raichur-PG1 & Raichur-PG2 lines have already retrofitted with numerical relays. The retrofitting of electromechanical relays with Numerical version for ICT- 1, ICT-2 and Munirabad line has been completed. Retrofitting work for Mehaboobnagar line is pending. Awaiting for line shutdown. 2. Job order placed on on M/s Alstom T&D India Ltd. Chennai for retrofitting of relays for all 220kV lines at RTPS. 3. Retrofit of existing bus bar(cag-34) with numerical version Budgetary offers obtained and is under process. Mail recieved on and : 1) Replacement of Old electromagnetic relays with Numerical relays has been completed for RTPS-BTPS line & commissioned on Raichur-PG1 & Raichur-PG2 lines have already retrofitted with numerical relays. The retrofitting of electromechanical relays with Numerical version for the following lines/icts have been completed/commissioned as follows: a) ICT-2 Commissioned on b) ICT-1 ---Commissioned on c) Munirabad line--- Commissioned on d) Mehaboobnagar line-- Commissioned on Job order placed on on M/s Alstom T&D India Ltd. Chennai for retrofitting of relays for all 220kV lines at RTPS. 3. Retrofit of existing bus bar(cag-34) with numerical version Budgetary offers obtained and is under process. Page 5 of 31

21 38/GD/3.5 GD-1 at Kadra and Kodasalli hydro power station at 19:31hrs A fault had occurred in 220 kv Kadra and Kodasalli. As A result, de-energization of 220kV bus occurred at Kadra and Kodasalli. 1. The PCSC forum requested KPCL to speed up the installation of Numerical Distance Protection relay in Kadra Kaiga and Kodasalli Kaiga. 2. The PCSC forum requested KPCL to submit the implementation status of PSAG-10 recommendations within a week s time. KPCL Mail recieved on : 1) e-nit floated on for procurement of Numerical distance relays & GPS. As there is change in scope of work and quantity of relays by more than 25%, which is not permitted as per KTPP act. Hence, tender cancelled and refloated on with revised scope of work and revised PQR. 2. However, as per the recommendations of PSAG, Relays were temporarily rearranged, replaced and wired up. testing & commissioning shall be completed with the assistance of KPTCL. Mail recieved on : 1. Cover -1 of the bid is scheduled for open eing on As per the recommendations of PSAG, Relays were temporarily rearranged. testing & commissioning completed with the assistance of KPTCL. Mail recieved on : NIT floated on through e-portal. Bid evaluation completed. Obtaining of Administration approval to place P.O is in progress. However, as per therecommendationsof PSAG-10, Relays weretemporarilyrearranged.testing & commissioning completed with the assistanceofkptcl. Mail recieved on : NIT floated on through e-portal. Bid evaluation completed. LOA's issued to M/s Schneider Electric Infrastructure Ltd. on Mail recieved on : LOA's issued to M/s Schneider Electric Infrastructure Ltd. on Engineering work is in progress. Status informed during Special Meeting held on : LOA s issued to M/s Schneider on Inspection of relays completed and received at site. DI issued for all balance materials except furnitures. 41/I/1 GD-1 at 220kV Kadra power Station of KPCL at 12:56 hrs Triggering incident was B-phase to earth fault had occurred in 220kV Kadra-Kodasalli line. Line tripped from Kodasalli end only. 220kV Kaiga-Kadra tripped in Zone-3 from Kaiga end. Tripping of evacuating lines caused bus shut down at Kadra hydro station. 1. KPCL to make functional the Main2 (EPAC) relay with the help of KPTCL at the earliest. 2. KPCL to investigate the reason for DC fuse fail during transient fault in 220kV Kadra-Kodasalli line including the testing/ checking of DC supply cables, breaker control cables, and trip coils. KPCL Mail received on : 1. Main-2 relays already installed and commissioned. 2. DC fuses are intact. Till date no such incidence occurred. 3. Possibility of DC-1 & DC-2 arrangement and splitting of DC will be reviewed. 3. KPCL to ensure supply for Main-1& Main-2 protections, Trip Coils (TC1, TC2) from separate battery banks. Mail received on , and : 1. Completed. 2. Completed. 3. Possibility of DC-1 & DC-2 arrangement and splitting of DC will be reviewed. 43/II/14 Tripping of 400/220kV ICT-1 at BTPS at 1:09 hrs ICT tripped due to operation of Over current and Earth fault relay KPCL to check the possibility of providing line differential protection between RTPS and Yermarus stations. KPCL KPCL vide their mail dated informed that revised relay settings would be incorporated in co-ordination with KPTCL. Mail received on , and : Revised relay settings are awaited from KPTCL. Revised relay settings furnished by KPTCL will be incorporated in coordination with KPTCL shortly. Page 6 of 31

22 46/II/21 Trippings at 220kV Raichur TPS at 01:35 hrs 1. KPCL to check the operation of anti-pumping relay on 220 kv side and keep it in healthy condition. 2. KPCL to provide manual reset to the 220 kv side master trip relay. 3. KPCL to use both the 220 kv buses as main buses under normal operation, and should go for single bus operation only during emergencies. KPCL Mail received on : 1) Anti-pumping contactors of all the nine 220KV Lines are in circuit and tested periodically during AOH works of lines along with other protections. 2) Completed. 3) Possibility to use both the 220kV buses as main bus under normal operation is under review. Mail recieved on : 1) Completed 3) Two bus operation for 220kV buses : In place of existing CT switching relays, High speed manual heavy duty change over switch of sufficient current capacity will be retrofitted to all feeders at 220kV station and same will be operated manually during changeover of feeder by one bus to the other and this arrangement may facilitate to put both buses in service. Time required for this retrofit is around 90days. However, this work will be taken up only after retrofitting of electromagnetic relays with numerical relays for Main-2 protection of all 220kV lines, for which work is in progress. 49/II/15 Trippings at Raichur TPS at 00:30 hrs Running Unit-4, 5 and Unit-8 and 400kV RTPS- Yeramaras TPS feeder got tripped due to deenergization of both 400kV Bus-1&2 at Raichur TPS 1. KPCL to carry out hot-line washing of RTPS-connected lines regularly to avoid trippings due to fog and dust. 2. KPCL may see the feasibility of providing breaker flashover protection at RTPS, and implement the same if possible. KPCL Status informed during Special Meeting held on : 1. Hot line washing was done previously.tender process is on for silicon coating of insulators. 54/I/4 Tripping of Nagjheri Generators at 12:29 hrs 220 kv Nagjheri - Bidnal line tripped on B-E fault at 12:28 Hrs. At the same time, five running generating units (1, 2, 3, 4 & 6) at Nagjheri tripped on operation of Generator Transformer s back-up Over Current & Earth Fault protection. 1. KPCL to revise the settings of GT s back-up O/C and E/F protections considering their individual contribution to solid bus fault at 220 kv bus of Nagjheri PH. 2. KPCL to upload/ make available various tripping files (FIR/DR/EL/TR) for all tripping involving their stations in compliance of IEGC Regulation 5.2 (r). KPCL Yet to be informed 54/II/4 Tripping of 400 kv Raichur TPS- Mahboobnagar line at 10:23 hrs Line tripped on operation of Backup impedance protection of line reactor. Direct trip was received at Mahboobnagar end. KPCL to keep the functioning of the concerned electro-mechanical back-up impedance protection relay under observation, and replace it with a spare at the earliest. KPCL Yet to be informed 54/II/9 Tripping of 400kV Raichur TPS Bus at 21:12 hrs Y-ph Pole of Tie-breaker of Unit-4 at RTPS failed. Unit-4 got tripped on operation of Generator Differential, Reverse power & LBB protection. Operation of LBB protection led to tripping of BUS-2 at RTPS 1.KPCL to undertake the following remedial measures to avoid breaker flashovers: (i) Replacing all porcelain insulators with composite insulators (ii) Carrying out hot-line water washing of all insulators on regular basis. (iii) Applying Room Temperature Vulcanizing (RTV) Silicone high voltage insulator coatings to all bus-connected ceramic insulators of equipment like CT, PT, CB, Isolators etc. KPCL Yet to be informed 2.KPCL to take steps to provide dedicated breaker flashover protection to all breakers at Raichur TPS at the earliest. Page 7 of 31

23 54/II/13 Tripping of Units at Raichur TPS at 15:36 hrs During testing of retrofitted distance protection In view of the availability of two buses along with healthy buscoupler at 220 kv RTPS, KPCL is recommended to put in service the in 400kV Raichur-2 feeder, LBB protection trip DC got extended to Bus trip. This resulted in double-bus operation at 220 kv RTPS by suitably distributing loads tripping of 220kV bus at RTPS and all within 15 days. connected 220 kv elements. Unit-4 which is connected to 400 kv Bus got tripped due to tripping of Station Utility Transformer that is connected 220 kv bus KPCL Yet to be informed 55/II/1 Multiple tripping at 400 kv Raichur TPS Station at 21:44 Hrs Triggering incident was failure of R-phase CT of 400/220kV ICT kV YTPS-RTPS line got tripped from YTPS end. 400kV RTPS- Mehaboobnagar line tripped on a B-phase to earth fault. 1.KPCL to enable zero-sequence compensation feature, if not already done, in all differential relays of transformers at RTPS. 2.KPCL to examine in detail the reasons for SOTF operation at RTPS end for the fault on RTPS-Veltoor line, and if required relay (configuration) settings at RTPS end may be suitably got revised with the help of their OEM. KPCL Yet to be informed 3.KPCL to take steps to enable auto-reclose for the Tie-CB s in the dias containing Munirabad and Veltoor (Mehboobnagar) at RTPS. 55/II/19 Tripping of 400kV Bellary TPS- Yeramarus TPS line and 400kVYeramarus TPS - Raichur TPS line at 17:21 hrs Direct Trip was sent from YTPS to RTPS and BTPS 1.KPCL to properly configure the distance relays at YTPS end on both YTPS BTPS line and YTPS-RTPS line with specific focus on reaches and timings of Zone-2, Zone-3, and Zone-4 (reverse). 2.KPCL to ensure the healthiness of Direct Trip circuits and relay coils at YTPS. KPCL Yet to be informed 3.KPCL to ensure time sync of DR s and EL s at YTPS with GPS. 56/I/2 Complete outage of 220kV Sedam Substation of KPTCL at 15:27hrs 220kV Sedam-Humnabad-2 tripped at Sedam KPCL to disable GFC protection on all lines emanating from their on Distance protection, Zone-2. Sedam-RTPS-1 generating stations. &2 lines tripped at RTPS end only. 220kV Tandoor inter-state line was hand tripped due to incoming supply failure KPCL Yet to be informed 57/II/3 Tripping of 400/220 kv ICT-2 at Raichur TPS at 3:32 hrs ICT-2 tripped on operation 400/220KV ICT-2 was tripped on operation of 220KV side Instantaneous over current protection during B- phase to earth fault in 220kV RTPS-Sedam-II line. KPCL to review appropriately the high-set of ICT s back-up O/C protection at their 220 kv RTPS so that they do not operate for a normal through fault. KPCL Yet to be informed 58/I/2 (GD) Complete outage of 220 kv Nagjheri PH of KPCL at 12:47hrs Bus dead occurred at 220kV Nagjheri PH due to tripping of evacuating lines. (i) KPCL to disable high-set operation of DEF relays (ii) KPCL to block DEF relays whenever corresponding distance protection relays pick up at Kodasally end on Nagjheri Kodasalli lines, and (iii)kpcl to provide stand-alone Event Logger at their 220 kv Nagjheri PH. KPCL Yet to be informed 58/I/3 (GD) Complete outage of 220 kv Kadra power station of KPCL at 14:40 hrs LBB of 220kV Kodasalli breaker at Kadra end (i) KPCL to check settings of LBB protection in all relays from which KPCL Yet to be informed got operated which resulted in tripping of Bus at it was implemented, and ensure that their configuration, logic, and Kadra and in turn led to tripping of all elements timing are in order at their 220 kv Kadra PH. (ii) KPCL to furnish details regarding the existing LT auxiliary supply arrangement at their 220 kv Kadra PH, and take steps to provide a suitable Auto-Main-Fail (AMF) panel for DG set to effect its auto-starting in case of failure of LT supply. Page 8 of 31

24 (iii) KPCL to ensure time-sync of all relays (DR s & EL s) with GPS at their 220 kv Kadra PH. (iv) KPCL to provide stand-alone Event Logger at their 220 kv Nagjheri PH. 58/I/5 (GD) Complete outage of 220 kv Sharavathy Tail Race PH at 11:19 hrs Spurious operation of LBB protection of line feeder had led to tripping of 220 kv bus at Sharavathy Tail Race power house. (i) KPCL to ensure the integrity of the connecting cable/ conductor from Generating Unit-3 to its corresponding GT breaker at their STR PH. (ii) KPCL to ensure the healthiness of Manual Current Regulator (MCR) of Unit-3 s AVR at their STR PH. (iii) KPCL to ensure the healthiness of AVR s of all Units of STR PH. (iv) KPCL to provide stand-alone Event Logger at their 220 kv STR PH. KPCL Yet to be informed 58/I/6 (GD) Disturbance in Kerala system at Partial disturbance occurred in central Kerala (i) SLDC, KSEB to put in place proper mechanism to ensure KPCL Yet to be informed 14:47 hrs grid due to overloading and tripping of 220 kv lines. Loss of in-feed to 220 kv Kalamassery, 220 kv Brahmapuram, 220 kv Ambalamugal, 220 Pallom & 220 kv Kochi occurred. Generation at Neriamangalam, Panniar, Chengulam and Pallivasal also got affected during the incident. adequate load-generation balance is maintained in their control area at all times, and due vigilance is exercised in operating an already depleted transmission network. (ii) KSEB to put UFR in service at New Pallom end on 220 kv New Pallom Amabalamugal line as part of Kudankulam Regional Islanding Scheme. 58/I/7 (GD) Complete outage at Varahi Hydro Power Station at 14:06 hrs LBB protection operated and caused bus shut down at Varahi PH (i) KPCL to check and correct configuration settings of LBB protection in all relays from which it was implemented, at their 220 kv Varahi PH. KPCL Yet to be informed (ii) KPCL to provide stand-alone Event Logger at their 220 kv STR PH. 38/GD/3.1 GD-1 at Mahalingapura Substation of KPTCL Fault had occurred in 220kV Mahalingapura-Narendra line-2. Due to the failure of relay operation at Mahalingapura, 1. PCSC forum recommended KPTCL to replace the old static distance protection relays with numerical relays. KPTCL breakers at remote end tripped which resulted in 2. PCSC forum also requested KPTCL to provide a broken conductor bus dead condition. alarm indication in Control Room. 3. Standing instruction needed to be given to the all substation personnel for not changing the relay settings without approval of RT/MRT wing. Mail received on (KPTCL) & : 1.Existing Back up relays will be replaced by numerical type distance relays.procurement is in tendering stage. 2. Completed. 3. Completed. KPTCL Mail recieved on : 1. Existing back up relays will be replaced by Main-2 protection. LOI issued M/s Alstom for taking up the works. KPTCL Mail Recieved dated : Under the Scope of R&U. The work will be taken up by M/s Alstom shortly. Page 9 of 31