SOUTHERN REGIONAL POWER COMMITTEE BENGALURU

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4 SOUTHERN REGIONAL POWER COMMITTEE BENGALURU Agenda for the 56 th Meeting of Protection Coordination Sub- Committee of SRPC to be held on 28 th July, 2016 (Thursday) 1. Introduction 2. Confirmation of Minutes of last PCSC meeting Confirmation of minutes of 55 th Protection Coordination Sub-Committee meeting held on Grid Occurrences 3.1 Grid Disturbance (GD), Grid Incidences (GI), and trippings due to failure of Autoreclosing (A/R), and Mal-operation of PLCC equipment that occurred during the period June, 2016 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: (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 June, 2016 has been brought to Constituents notice vide SRPC letter No. SRPC/ SE-III/ PCSC- 56/ 2016/ dated The 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 54 th PCSC) given at Annexure-II may please be sent latest by Remedial measures for "Transmission Elements under Forced Outage" The Constituents are requested to send the remedial measures/ actions taken by them for the tripping events as circulated vide our s. (Annexure-III) The trip events are based on the daily reports at SRLDC website DailyReport.aspx under the menu: Reports->Daily-> "TL under Forced Outage")

5 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 June, 2016 is still awaited from the following SR-Constituents: APGENCO (Hydro), APTRANSCO, TSGENCO (Hydro), TSTRANSCO,, TANGEDCO, PGCIL (SR-I), NTPC (Ramagundam), NPCIL (MAPS) & CEPL 5. Protection Audit Time-lines and Furnishing the Status of Protection Audit Remarks by SR-Constituents As you are kindly aware, consequent to grid disturbances in July, 2012, Third Party Protection Audit (TPPA) has been carried out for certain Stations in the Southern region. Based on their assessment of the protection systems in place, the visiting TPPA had given certain recommendations for implementation. SRPC has been entrusted with monitoring the implementation of these protection audit recommendations (PAR) vide CERC Order dated in respect of Petition No. 146/MP/2013 with I.A. 36/2013. Further, as per CERC Order dated in respect of Petition Nos. 86/MP/2014 and 374/MP/2014, SRPC is to submit a bi-annual report on the status of implementation of PAR to CERC. In this regard, SRPC vide their letter no: SRPC/SE-III/PAR/2016/ dated (copy enclosed at Annexure-IV) requested the addressed SR- Constituents to furnish the following: The action taken by them in terms of obtaining further time-extensions (kindly mention CERC Petition & Order No.) and the measures taken to implement their respective PAR. The latest status of implementation of pending remarks (pertinent to their Stations). As requested therein, all addressed SR-Constituents are requested to kindly provide the above details latest by for filing a consolidated reply before Hon ble CERC. A soft copy of the same (in Excel format) may also please be ed to srpc.protection@gmail.com 6. Other Protection Issues, if any, with the permission of the Chair 7. 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. 8. Date of next PCSC meeting The 57 th PCSC meeting would be conducted on (Wednesday) at 10:30 hrs in the Conference Hall of SRPC, Bengaluru. ***** Agenda for the 56 th Meeting of PCSC to be held on 28 th July, 2016 Page 2

6 Annexure-I I. Details of Grid Disturbances: Grid Occurrences - 56 Sl. No. Details of Event Date &Time Reason Remarks Category 1 Complete outage of 400/220kV Hoody substation of at 4:56 hrs Bushing of R-phase ICT -2 got failed at Hoody station at 3:09 hrs. ICT-1&3 and 400kV lines at Hoody substation were hand tripped at 4:56 hrs for fire extinguishing. Load loss : 700MW GD Complete outage of 220kV Sedam Substation of. Complete outage of 220kVAmbewadi Station of at 15:27hrs at 20:57hrs 220kV Sedam-Humnabad-2 tripped at Sedam on Distance protection, Zone-2. Sedam- RTPS-1 &2 lines tripped at RTPS end only. 220kV Tandoor interstate line was hand tripped due to incoming supply failure B phase to earth fault had occurred in 220kV Ambewadi- Ponda line-2. Fault was cleared by tripping of feeders from remote end Load loss : 123MW Load loss : 70MW GD-1 GD-1 II. Details of Grid Incidents: Sl. No Details of Event Date & Time Reason Remarks Category Bellary TPS-JSW line Report on tripping of 400/230 kv Neyveli TS-2 ICT-1 Report on tripping of 400/230 kv Neyveli TS-2 ICT-1 and 2 Tripping of HVDC Bhadrawati pole-1 Vallur- Kalivandapattu line at 3:00 hrs at 07:51 Hrs at 07:58 Hrs at 5:56 hrs at 23:15 hrs As per verbal information line tripped on operation of overvoltage. ICT-1 tripped on operation of 400kV side over current protection ICT-1&2 were tripped on over loading As per verbal information HVDC pole-1 tripped Valve cooling problem Line tripped on Y-phase to earth fault. AtKalavindapattu end Zone1 Fault and Power swing detection was sensed by distance relay and caused 3- phase tripping. Direct trip was sent to Vallur TPS Page 1 of 3

7 Annexure-I Tripping of 220kV Ambewadi-Ponda line-1&2 Udumalpet- Tirunelveli line-2 Tripping of HVDC Talcher-Kolar Pole-1 Guttur-Narendra line-1 Tripping of HVDC Gazuwaka Pole-1 Tripping of HVDC GazuwakaPole-2 Tripping of HVDC Talcher-Kolar Pole at 11:20hrs at 18:56 hrs at 16:35 Hrs at 21:08 hrs at 5:20Hrs at 5:20 Hrs at 5:28Hrs FIR was not submitted for the tripping line tripped at Tirunelveli end and was holding from Udumalpet. Tirunelveli - Udumalpet Line 2 tripped on operation Zone-4 of Distance protection Main-2 relay Talcher-Kolar HVDC Pole-1 got tripped on line fault and Pole-2 went to ground return mode with 150MW line tripped at Guttur end and was holding from Narendra due to CB low air pressure Pole-1 tripped due to operation of south filter inter zone filter protection which was due to failure of south side B-phase CT (CWD-30). Hvdc Pole-2 got tripped on operation of Bus differential protection Blocked on Y-phase PRD operation Tripping at 220kV GootySubstaiton of APTRANSCO Cudappah-Chitoor line Multiple tripping at 400/220kV Gutur substation of Tripping of 400KV Gajwel-Singareni line-2 400KV Veltoor - Raichur Line at 16:04 hrs at 23:54 hrs at 11:27 hrs at 23:43 hrs at 22:01hrs LBB protection got operated for 400/220kV ICT-2 breaker which had resulted in tripping of 220kV Bus-2 at 220kV Gooty Substation line tripped on operation of overvoltage stg-1 protection at Chitoor and Direct trip was received at Cudappah bus bar protection relay of 220kV Bus-1 got operated during the fault in the 220kV GutturJogihally IPP line Tripped on 3 phase trip atgajwel end Tripped on operation of over voltage protection at Raichur and direct trip received at Veltoor. III. Trippings due to failure or non-operation of Auto reclose Sl. No. 1 Element Date & Time Reason Ramagundam-N Sagar line at 19:24 hrs line tripped on B-phase to earth fault. Auto-reclose was successful at Ramagundam TPS end and auto- Page 2 of 3

8 Annexure-I Khammam- Mamidapalli line-2 Shankarapalli-Mamidapalli line-2 Tripping of 220kV Sedam- Tandur line Neyveli TS- 2-Pugalur line Warangal- Bhoopalapalli Khammam- N sagar line-1 Hassan- UPCL line-2 NCTPS- S.V.Chatram line-1 NCTPS- S.V.Chatram line at 20:18 hrs at 20:58 hrs at 21:52 hrs at 16:36 hrs at 20:45 hrs at 22:41 hrs at 12:16 hrs at 15:47 hrs at 18:21 hrs reclose did not operated at N sagar end line tripped on R-phase to earth fault. Auto-reclose was successful at Mamidapalli end, however breakers got tripped on receipt of direct trip at Mamidapalli line tripped on R-phase to earth fault. Line did not auto-reclose line tripped on B-phase to earth fault. Auto-reclose is not enabled for line. B phase to earth fault had occurred in line. Auto-reclose did not operate at NLC TS-2 and DT was sent to Pugalur end resulting in a 3 phase trip Line tripped on a R-phase to earth fault. Auto-reclose was successful at Bhoopalapalli and unsuccessful at Warangal Line tripped on B-phase to earth fault. Line auto-reclosed successfully at N sagar and failed to reclose at Khammam Line tripped on a Y-phase to earth fault. Auto-reclose was successful at UPCL end and Hassan end did not reclose and tripped in zone-2 time Line tripped on R-phase to earth fault. Auto reclosure locked out at both end due absence of carrier protection line tripped on Y-N fault. A/R is not in service due to absence of carrier protection IV. Tripping of lines on one end/ PLCC mal-operations Sl. No. 1 2 Element Date & Time Reason Raichur(PG)- Gooty line-1 VTPS- Suryapet line at 3:24 hrs at 16:55 hrs at 14:18 hrs Line tripped on operation of overvoltage protection at Gooty end. Line did not trip from Raichur(PG) as direct trip was not received direct trip was received at VTPS and line was holding from Suryapet end line tripped at VTPS and did not trip at Suryapet Page 3 of 3

9 Implementation of PCSC Recommendations (up to 54th Meeting) Meeting No / Index Details of Event Date & Time Reason PCSC Recommendations Utility responsible for Implementation Status of Recommendations as on Remarks Andhra Pradesh 49/II/13 Tripping of running Units 1 & 3 at at 03:30 hrs Rayalaseema TPS of APGENCO While synchronizing Unit-5 with grid, Bus bar protection of 220kV Bus-1 operated which resulted in deenergization of 220kV Bus-1. This resulted in tripping of running Unit- 1&Unit-3, 220kV lines Pulivedula-1, Yeralaguntla-1, Chinakampalli-1, Timmapura In view of the availability of 25AX, APGENCO shall keep synchronizing facility in auto-mode after getting it s operation verified by its OEM, M/s BHEL. APGENCO Yet to be informed 52/I/2 (GD) Complete outage of kV Yerraguntla at 10:39 hrs substation and tripping of running Units at Rayalaseema TPS 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 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 inter-state 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 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 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 to arrange ABB make ETL-41 cabinet with NSD-50 type protection coupler for establishing PLC communication between Alipura- Ragulapadu. Mail recieved on : 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. Page 1 of 21

10 50/II/14 Tripping of 220kV Chittoor-Tiruvalam at 11:20 hrs During testing of DC earth leakage, DC 1. APTRANSCO to furnish SLD of 220/132 kv Chittoor SS, got extended to bus bar protection relay. Hence bus bar protection operated and 2. APTRANSCO to confirm whether 220 kv side is on singlebus operation with only one main-zone. If so, APTRANSCO shall tripped the 220KV BUS connected transformers and feeders. examine the feasibility of providing split-bus operation or multiple main-zones for bus bar protection, and take necessary steps to implement it. APTRANSCO 1. SLD furnished vide APTRANSCO mail dated Completed. 2. APTRANSCO vide their mail dated that 220KV chittoor substation is a old 220KV substation with single bus operation. Bus bar protection has both main & checkzone are in service /II/1 Tripping of 400 kv Chittoor- at 9:55 hrs Sriperambadur line line tripped on operation of line reactor APTRANCO to take steps to ensure that DR and EL are protection at Sriperambadur end and configured for recording DT receipt event at their direct trip was sent to Chitoor. Buchholz 400 kv Chittoor substation. relay of line reactor of 400kV Chitoor- Sriperambadur got operated at Sriperabadur end. APTRANSCO APTRANSCO mail dated on : The compliance report will be furnished after completion of configuration. Telangana 47/II/6 Khammam-KTPS line at 6:08 hrs Y-phase to earth fault had occurred in line. From Khammam end DR it was observed that the relay after dead time tried for auto-reclose. The fault was persisting and relay gave a single phase trip instead of a 3 phase trip after 1.25sec. R& B pole voltage dip after 2 sec possibly due to operation of pole discrepancy. Auto-reclose close command observed after 2.5 seconds and all poles got closed. 1. TSGENCO to check the reclaim time of A/R and set it at 25 sec at KTPS. 2. TSGENCO to carry out PLCC end-to-end testing in coordination with PGCIL (SR-I) for KTPS Khammam line-2; retrofitting of Protection Coupler may be carried out based on the test results. TSGENCO Yet to be informed 54/II/16 Sattenapalli- Srisailam line at 1:40 hrs Line tripped on Direct Trip receipt at Sattenapalli end TSGENCO to resolve configuration problems associated with the newly commissioned relays at 400 kv Srisailam LB latest by so that unwarranted DT sending to remote end substations of APTRANSCO is addressed. TSGENCO Yet to be informed Sattenapalli- Srisailam line at 13:40 hrs R-Ph to earth fault had occurred in line. Direct Trip receipt was observed in DR of Sattenapalli and Srisailam. 44/III/2 Ghanapur- Mamidapalli line at 2:03 hrs Line tripped at Mamidapalli end only and was holding at Ghanapur. Overvoltage protection had operated at Mamidapalli TSTRANSCO to make DR functional at Mamidipalli TSTRANSCO TSTRANSCO informed vide their mail dated that the existing relays would be replaced with numerical relays in DPR works. 48/II/ Nagarjunsagar- at 2:58 hrs Mahboobnagar line Line tripped on operation of overvoltage protection at Mahboobnagar and along with remedial measures taken to PCSC forum. TSTRANSCO to furnish a detailed report on the tripping event 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 Yet to be informed Page 2 of 21

11 validate the overvoltage tripping 48/III/4 Tripping of 220kV Gajwel- Shankarapally line at 2:24 hrs line tripped at Gajwel end on R-Phase to ground fault. Reason for non-auto reclose could be established as DR and EL of both ends were not furnished TSTRANSCO to furnish a detailed report on the tripping event along with remedial measures taken to PCSC forum. TSTRANSCO Yet to be informed 51/IV/1 Gajwel-Hyderabad at 6:11 hrs and 7:11 hrs Line tripped at Gajwel end only due to suspected PLCC mal-operation at Gajwel end TSTRANSCO to check the integrity of all DR s and EL s, and sort out communication related issues at 400 kv Gajwel SS. TSTRANSCO Yet to be informed 52/I/6 54/II/2 Complete outage of 220kV Malyalapalli station of TSTRANSCO Shankarapalli - Mamidapalli line at 18:41 Hrs at 00:03 hrs CT failure occurred in 220kV Ramagundam-Malyalapalli line-1 at Malyalapalli end. The CT failure resulted into a Bus fault. All 220kV lines and transformers at Malyalapalli station tripped during the incident. Y-Phase CT failure had occurred in 400kV Shankarapalli-Mamidapalli line at Mamidipally end. TSTRANSCO to furnish the Equipment Failure Report for the R- ph CT blast to Power System Engg & Technolgy Divison (PSETD) of Central Electricity Authority with a copy marked to SRPC. 1.TSTRANSCO to revise A/R dead-time on 400 kv Shankarapalli Mamidipalli to 1 sec at both ends. 2.TSTRANSCO to furnish Equipment Failure Report of Y-ph CT blast to CEA with a copy marked to SRPC. TSTRANSCO Yet to be informed TSTRANSCO Yet to be informed Karnataka Page 3 of 21

12 30/I/A RTPS Tripping incidents and the Spl meeting held at RTPS on 13th and 14th March 2014 Mar-14 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. 38/GD/3.5 GD-1 at Kadra and A fault had occurred in 220 kv Kadra 1. The PCSC forum requested KPCL to speed up the KPCL Mail recieved on : Kodasalli hydro at 19:31hrs installation of Numerical Distance Protection relay in Kadra power station Kaiga and Kodasalli Kaiga. and Kodasalli. As A result, deenergization of 220kV bus occurred at Kadra and Kodasalli. 2. The PCSC forum requested KPCL to submit the implementation status of PSAG-10 recommendations within a week s time. 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 Page 4 of 21

13 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. 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. 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 assistanceof. 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. Annexure-II 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 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. 3. KPCL to ensure supply for Main-1& Main-2 protections, Trip Coils (TC1, TC2) from separate battery banks. 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. 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. Mail received on , and : Revised relay settings are awaited from. Revised relay settings furnished by will be incorporated in coordination with shortly. Page 5 of 21

14 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 de-energization 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- at 10:23 hrs Mahboobnagar line 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 electromechanical back-up impedance protection relay under observation, and replace it with a spare at the earliest. KPCL Yet to be informed 54/II/ Raichur TPS Bus-2 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 6 of 21

15 54/II/13 Tripping of Units at Raichur TPS at 15:36 hrs During testing of retrofitted distance protection in 400kV Raichur-2 feeder, LBB protection trip DC got extended to Bus trip. This resulted in tripping of 220kV bus at RTPS and all 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 In view of the availability of two buses along with healthy buscoupler at 220 kv RTPS, KPCL is recommended to put in service KPCL the double-bus operation at 220 kv RTPS by suitably distributing loads within 15 days. Yet to be informed 38/GD/3.1 GD-1 at Mahalingapura Substation of Fault had occurred in 220kV Mahalingapura-Narendra line-2. Due to the 1. PCSC forum recommended to replace the old static distance protection relays with numerical relays. Mail received on () & : 1.Existing Back up relays will be replaced by numerical type distance relays.procurement is in tendering stage. failure of relay operation at Mahalingapura, 2. PCSC forum also requested to provide a broken conductor alarm indication in Control Room. 2. Completed. 3. Completed. breakers at remote end tripped which resulted in bus dead condition. 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 recieved on : 1. Existing back up relays will be replaced by Main-2 protection. LOI issued M/s Alstom for taking up the works. Mail Recieved dated : Under the Scope of R&U. The work will be taken up by M/s Alstom shortly. 39/I/5 Tripping of 400/220kV ICT-2 at Hoody substation of Suspected mal-operation of 220kV side Rphase over current relay 1. PCSC forum recommended to replace the relay with a different make. 2. was also requested to train the O&M personnel adequately before performing any maintenance works to avoid such unwanted trippings. Mail received on & : 1. C&R panels of 500MVA ICT 1&2 will be replaced under scheduled R&M works. 2. O&M personnel are instructed to take sufficient care in order to avoid unwarrented trippings. --- Completed. mail received on : New C&R panels(with numerical relays) erected for 500MVA ICT-1 &2 under R&M work, which will be commissioned shortly. mail received on : New C&R panels(with numerical relays) erected for 500MVA ICT-1 &2 under R&M work, which will be commissioned shortly. 40/I/1 GD-1 at 220kV Ambewadi Station of at 21:22 hrs Triggering incident was B-phase to earth 1. Till the completion of R&M works for bus bar and LBB fault in 220kV Ambewadi- Nagzari line- protection, shall explore the possibility of having split 1. B-pole of breaker did not open at bus operation at Ambewadi and submit the details of the same to Ambewadi end. LBB protection not PCSC forum. available at Ambewadi end. All elements tripped on Zone-2 from remote ends. 2. shall provide the details of the tripping of Supa hydro station connected downstream from 110 kv bus. Mail received on : 1. In view of operating 220kV Ambewadi SS in split bus mode, action is being taken up by. Problem in the 220kV bus coupler breaker is attended and isolator overhauling work is under progress. Spilt bus operation at Ambewadi will be made possible at the earliest. Page 7 of 21

16 2. ICT protection system at Ambewadi and trippings occured at Supa GS during the instance is checked up and remedial measures already furnished in this regard Completed Mail recieved on : 1. Action is being taken by for operating Ambewadi in split bus mode. Problem in bus coupler breaker is attended.isolator overhaulling work is completed.pts are already provided to 220kV Bus-II. After commissioning of Bus-II PTs, Ambewadi can be operated in split bus mode. works will be completed within a months time. mail recieved on : Bus-II PTs yet to be commissioned.planned to complete before end of April /IV/1 220kV Sedam- Tandur line at 22:20 hrs Line tripped on Yphase to earth fault from both the ends was requested to explore the possibility of providing A/R feature to this line and submit the remedial measures to the PCSC forum. Mail recieved on : Carrier protection is being restored for 220kV Sedam-Tandoor line at Sedam end. After restoring the carrier protection, AR will be enabled. mail recieved on : Carrier protection is being restored for 220kV Sedam-Tandoor line at Sedam end. After restoring the carrier protection, AR will be enabled. mail recieved on : SEE,SCADA to update the latest status mail recieved on : Action is being taken to restore carrier protection.ar will be enabled once carrier signal is restored. 41/I/4 Complete outage at kV Sedam at 8.00 hrs Substation of (GD-1) R-Phase to ground fault occurred on 220kV Sedam-Shahpur line. Fault not cleared from Sedam end due to stuckbreaker condition. While the Sedam- Sahapur line tripped from Shahapur end in Zone-1, the other 220 kv lines from Sedam tripped at remote ends in Zone-2. This caused complete outage of 220kV Sedam substation. 1. to provide Bus bar and LBB protections for 220 kv bus at Sedam S/s. 2. to implement A/R feature on 220 kv Sedam-Tandur inter-state line. Mail received on : Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR will be enabled. Mail received on : 1. Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection for 220kV Sedam- Tandoor line. AR will be enabled after restoration of PLCC. mail received on : 1. Bus bar protection panels pocured and erected at Sedam. Wiring, testing,commissioning is being taken up.planned to complete by April Action is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR will be enabled after restoration of PLCC. Page 8 of 21

17 42/I/1 (GD) Complete outage of kV Sedam at 14:24 hrs substation of Fault occurred in 220kV Sedam-Shahpur line 1. to provide Bus Bar protection and LBB protection at Sedam S/s and furnish the status of their implementation to PCSC forum. 2. to implement A/R feature on 220 kv Sedam-Tandur inter-state line. Mail received on : 1. Bus Bar protection will be provded under R&U. 2. A/R yet to be enabled. Mail received on : 1. Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection for 220kV Sedam- Tandoor line. AR will be enabled after restoration of PLCC. 42/I/2 (GD) Complete outage of kV Ambewadi at 7:51 hrs substation of Fault in 220kV Ambewadi-Nagjheri line shall provide A/R feature on Ambewadi Ponda 220 kv D/C inter-state line. 2. Till the completion of R&M works for bus bar and LBB protection, shall explore the possibility of having split bus operation at Ambewadi and submit the details of the same to PCSC forum. Mail received on : 1. Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection for 220kV Sedam- Tandoor line. AR will be enabled after restoration of PLCC. 47/II/13 Tripping of Unit- 1&2 along with 400/220kV ICT-2 at Raichur TPS at 4:51 hrs 220kV RTPS-Lingasugur line-2 tripped to activate non-directional Over Current protection with a at TPS end on operation of distance time delay of msec for Fuse protection zone /220kV ICT-2 got failure condition at Lingasugur. tripped on operation of earth fault protection. 220kV RTPS-Lingasugur line-1&3 tripped on distance protection zone-2 and zone-3 respectively. Due to tripping of ICT-2, the running units got overloaded and it was mentioned that under frequency occurred as units are on load control. The Units got tripped on under frequency. Yet to be informed 47/III/8 Tripping of 220kV Ambewadi-Ponda line at 13:20 hrs Line tripped on a transient fault in B- phase. There is no provision for auto reclose. Till A/R is put into service on Ambewadi-Ponda line-1, to reduce Zone-2 time setting to zero sec. at Ambewadi end. Yet to be informed 47/III/10 47/III/12 Tripping of 220kV Ambewadi-Ponda line-1 Tripping of 220kV Ambewadi-Ponda line at 10:51 hrs and at at 13:20 hrs Line tripped on a B-phase to earth fault. Line tripped as there is no provision for auto-reclose Line tripped on a transient fault. There is no provision for Auto reclose. 48/I/2 (GD) Complete outage of 220kV Peenya Substation in Karnataka at 4:23:17 hrs All connected 220kV lines and transformers were taken on 220kV North bus as South bus was under shut down for conversion of strung bus to rigid bus and isolator replacement under R&M works. Failure of HV side Y phase CT of 150MVA Transformer-3 to revise distance relay settings at Nelamangala end for 220 kv Nelamangala Hebbal - Peenya line 1 for the effective line length of 17 km. These new settings can be appropriately reviewed as and when the tie-arrangement at Hebbal is done away with. mail received on : Presentl 220kV Nelamangala -Hoody(i.e. nelamangala-peenya-hebbal - Hoody line is made LIILO at Yelahanka sub station and breaker at Peenya is kept open, necessary modification in distance relay settings adopted for new configuration. Page 9 of 21

18 phase CT of 150MVA Transformer-3 occurred at Peenya Substation which resulted in operation of Differential and HV REF protection. The failure of CT also resulted in a 220kV bus fault in North Bus. 48/I/3 (GD) Outage of 220kV Ambewadi station in Karnataka at 10:41 hrs 220kV Ambewadi-Nagjheri line-2 tripped on B-phase to earth fault. This resulted in loss of supply to 220kV Ambewadi bus. 220kV Ambewadi- Ponda line-1&2 were hand tripped after deenergization of bus at Ambewadi. to fast-track providing A/R on all 220 kv lines emanating from Ambewadi SS to prevent Station shut-down on temporary faults. mail received on : Will be complied in a months time. Page 10 of 21

19 48/I/4 (GD) Complete outage of 220 kv HSR substation of Karnataka at 16:32 hrs All connected 220kV lines at 220kV to review distance relay settings at Naganathpura SS in HSR substation i.e. Somanahalli, EPIP, view of LILO arrangement at HSR Lay-out. Hoody and Nagnathapura tripped during the incident. Triggering incident was fault in 220kV HSR-EPIP line mail received on : ABB make REL 670 type distance relays provided to Somanahalli and hoody lines. Planned to commission within 10 days. Mail recieved dated : New REL 670 relays erected in the panel. Testing and commissionng will be done within a month's time. 49/I/1.3 (GD) Complete outage of 220kV Ambewadi Substation of at 14:34 hrs 220kV Nagjheri-Ambewadi line-1 tripped at 13:33 hrs due to B phase to earth fault. Ambewadi was radially fed from Nagjheri power station through 220kV Nagjheri-Ambewadi line-2. Tripping of this line caused 220kV Bus shut down at Ambewadi and remaining lines and transformers were hand tripped 1. KPCL to provide A/R on all 220 kv lines emanating from Nagjheri PH. 2. to provide A/R on all 220 kv lines emanating from Ambewadi SS. Yet to be informed 51/II/21 Multiple tripping at 400kV Guttur substation at 18:53 hrs Failure of Lightning Arrestor of Y-phase Line Reactor of 400kV Guttur-Hiriyur line-1 and line tripped on distance protection Zone-1. Bus-bar protection of 400kV Bus-2 at Guttur substation also got operated during the event sensing this through fault. 400/220 kv ICT-1 & 2 at Guttur, 400kV Kaiga-Guttur-2, 400kV Guttur-Narendra-2, 400kV Guttur- Hiriyur-2 and 400kV Guttur-Munirabad which are on 400kV Bus-2 got tripped during the incident. 400kV Guttur- Narendra-1 which was on Bus-1 also tripped at the same time. 1. to configure all DR s and EL s at 400 kv Guttur SS so that they will also get triggered for BBP operation. 2. to ensure time-synchronization of all DR s and EL s with GPS at their 400 kv Guttur SS. Mail received dated : SEE, RTC, Bangalore to update the status Mail received dated : Providing numerical bus bar protection to 400kV buses and GPS time synchronising equipment at Guttur is considered under R&U. Work is awarded to M/s Alstom, execution will be taken up shortly 52/I/3 (GD) Complete outage of 220kV Shimoga substation at 15:03 hrs 220kV Bus Bar protection operated during failure of R phase CT in DVG-2 line bay. to operate 220 kv Shimoga on multi-bus operation under normal conditions, put it on single-bus operation only under emergency conditions. Yet to be informed 53/I/1 Complete outage of 220kV Peenya Substation of at 11:39 Hrs 220kV Peenya-Nelamangala-3 tripped on B-E fault at both ends. At the same time, 220kV Peenya-Nelamangala-4 tripped on R-Y fault only at Nelamangala end, and was in service from Peenya end. Due to tripping of these two lines, 220kV Peenya- Nelamangala-2 tripped on overcurrent protection. to furnish a report on the tripping of 220 kv Peenya- Nelamangala line-4 Nelamangala detailing the remedial measures taken including the settings adopted for Z1B (Zone extension) and Power Swing Block. Mail received dated : SEE, RTC, Bangalore to update the status 51/I/3 Complete outage of kV Nagjheri at 12:36 hrs power station and 220kV Ambewadi substation of 220kV lines from Nagjheri power house started tripping from 11:00 hrs due to fault in lines. The sequence of tripping is shown in SOE list. At 12:33 hrs, 220kV Narendra-Ambewadi lines-1&2 got tripped which resulted in loss of evacuation path to Nagjheri station 1. To avoid tripping of transmission lines on transient faults, KPCL/ is recommended to carry out periodic patrolling of lines, and ensure their proper maintenance by carrying out jungle/ bushing clearance and trimming of tree branches within the RoW of transmission lines as per the SRPC transmission line patrolling guidelines (available under the menu item "All Uploads Operation Miscellaneous Transmission Line KPCL/ Status informed during Special Meeting held on : 1. informed that the matter had been taken up with concerned Line Operation and Maintenance wing to carry out corridor clearance and maintenance as per schedule to avoid frequent line faults in this corridor. A letter had also been addressed to Chief Engineer, Bhagalkot zone, to ensure lines in & around Kali complex are maintained in healthy condition. --- Completed Page 11 of 21

20 evacuation path to Nagjheri station Uploads resulting in tripping of running Units Patrolling Protocol / Guidelines for Southern Region" on SRPC and complete outage at Nagjhheri power website). station. 220kV Ambewadi station also 2. KPCL/ to review operation of SPS at NPH for got de-energized due to tripping of functionality (reduction of generation with tripping of evacuating source feeders i.e. 220kV Narendra- lines) and healthiness. Ambewadi-1&2 and 220kV Nagjheri- 3. KPCL to put 220 kv Kodasalli - Nagjheri D/C lines into Ambewadi-1&2. service if more than 200 MW generation from Kali Complex (with Nagheri Contribution not less than 50 MW) is ensured on sustained basis. condition. --- Completed 2. assurd that the final modified SPS would be implemented at Nagjheri PH at the earliest KPCL informed that Nagjhari- Kodasalli Lines 1 & 2 had been kept in service since 08.06hrs Completed Mail received dated : Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC for verification and approval 53/I/3 (GD) Complete outage of 220kV Ambewadi station of and 220kV Nagjheri of KPCL at 14:40 hrs Ambewadi Narendra line-2 tripped on fault and 220kV ambewadi Narendra line-1 tripped due to over-loading. Running Units at Nagjheri also tripped during the event due to tripping of evacuating lines 1. KPCL to furnish a report on the reasons for Unit-6 tripping at Nagjheri PH. 2. KPCL/ to modify suitably the SPS at Nagjheri Power House such that it would also factor in the over loading of Ambewadi-Narendra lines. KPCL/ Mail received dated : Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC for verification and approval 3. KPCL to put 220 kv Kodasalli - Nagjheri D/C lines into service if more than 200 MW generation from Kali Complex (with Nagheri Contribution not less than 50 MW) is ensured on sustained basis. 53/II/1 Tripping of ICT-3 at Raichur Substation at 12:28 hrs ICT-3 tripped due to operation of backup earth fault protection during fault in 220kV RTPS-Raichur line-1. KPCL/ to check the ICT s back-up (high-set) protection settings, and ensure that they operate with a time delay of 100 msec. KPCL/ Mail Recieved dated : SEE,SCADA to update the status of healthiness of carrier protection of 220kV RTPS-Raichur 1 &2 lines Mail Recieved dated : Details sought from KPCL for review of ICT's back up (high set) proection settings as suggested. KPCL is yet to furnish the details required to give the revised settings. Tamil Nadu 43/II/5 Alamathy- SVChatram line- 1&2 and 400/230kV ICT at S.V.Chatram at 15:29 hrs Line-2 tripped on R-phase to earth fault. TANTRANSCO was requested to swap the relays between two stations, so that Line autoreclosed at SVChatram end Main-1 and Main-2 will be of different make at each station. and failed to reclose at Alamathy end. Bphase to earth fault in line-1. Line tried for A/r but due to permanent fault line did not reclose. ICT tripped on operation of over flux protection. TANTRANSCO TANTRANSCO vide their mail dated informed that different relays in Main-I & Main-II would be ensured at the earliest. Mail recieved on , and : Different relays in Main-I & Main-II will be ensured. Mail received on : TANTRANSCO: Not feasible in the existing SAS sub stations. Hence, exemption may be given for these sub stations. Mail received on & : As discussed in the 52nd PCSC meeting, Swapping of Relays between two stations is not feasible in the existing SAS sub stations. Hence, exemption may be given for these sub stations. 48/I/1 (GD) Disturbance in 220kV Tamilnadu system at 14:04 hrs Complete outage of 230kV Palladam, 230 kv Othakalmandapam S/s, 230 kv Coimbatore S/s, 230 kv Thudialur and 230 kv Sadayapalayam S/s TANTRANSCO to take suitable measures like installing more TANTRANSCO stub-towers along 230 kv OK Mandapam Myvady line to avoid excessive sag due to over-loading. TANTRANSCO Mail received on , and : 230kV Othakalmandapam - Myvadi feeder will be made LILO at Kongal Nagar. Line restringing will be carried out along with the above proposal. Mail Received on & : 230kV Othakalmandapam - Myvadi feeder will be made LILO at Kongal Nagar. Line restringing will be carried out along with the above proposal. Page 12 of 21

21 50/I/3 (GD) Complete outage of 230kV Mywadi station of TANTRANSCO at 6:28 hrs Busbar protection got operated for a 1. TANTRANSCO to examine the feasibility of providing two fault in 230kV Mywadi-Anaikadavu line main-zone operation for bus bar protection by exploring various alternatives like replacing existing bus-coupler CB with a hybrid bus-coupler CB that comes with inbuilt CT, replacing existing BBP relay with another suitable relay that supports two mainzone operation, and implement the same. TANTRANSCO TANTRANSCO Mail received on and : Revision of Bus Bar Protection setting was carried out. The stabilizing voltage setting was raised from 410 to 450 volts. After completing the necessary test, the bus bar protection put in to service on Mail recieved on & : Revision of Bus Bar Protection setting was carried out. After completing the necessary test, the bus bar protection put in to service on /II/17 Tripping of /230kV Myvadi at 17:26 hrs ICT-3 400/230kV Myvadi ICT-3 tripped due to the operation of 230 kv CB LBB protection at 230 KV bus (TNEB) of Myvadi station. TANTRANSCO to check the LBB scheme for LV side CB of ICT-TANTRANSCO TANTRANSCO Mail received on , and , and furnish the remedial measures taken to PCSC forum. 2016: LBB scheme will be tested while availing Line Clear. Mail Received on & : Revision of Bus Bar Protection setting was carried out. After completing the necessary test, the bus bar protection put in to service on /I/1 (GD) Complete outage of kV Madurai S/s at 11:56 hrs (Chekanaurani) of TANTRANSCO Fault had occurred in 230kV Madurai- Sembatty line. Trip from distance relay was not extended to breaker due to protection DC fail. LBB protection got operated resulting in a busbar trip at 230kV Madurai substation. All elements got tripped as there is a single bus operation at 230kV Madurai S/s 1. TANTRANSCO to provide split-bus operation with bus sectionalizer CB for their 230 kv Madurai (Chekanurani) SS. 2. TANTRANSCO to provide two main-zone operation for the numerical BBP that is being commissioned. 3. TANTRANSCO to examine the feasibility of providing Re- Trip feature for the LBB protection, and accordingly take steps for implementing the same. TANTRANSCO TANTRANSCO mail received on : CMR relay for extending LBB protection was released and LBB extended from Distance Protection relay directly. CT is not available in the Bus Coupler bay for zone segregation. However, during commissioning of third ICT, Bus section Breaker will be provided for zone segregation. Numerical BBP relay will be provided. Mail recieved on and & : CT is not available in the Bus Coupler bay for zone segregation. However, during commissioning of third ICT, Bus section Breaker will be provided for zone segregation. Numerical BBP relay will be provided. Page 13 of 21

22 Kerala 44/I/1 (GD) Complete outage of Idukki Hydro Power Station (GD- 1) at 12:30 Hrs 220 kv breaker of unit-3 at Idukki Power house flashed and bus differential protection acted. All Generators (6Nos.) along with all 220 kv feeders tripped during the incident. 1. KSEB to reduce sensitivity of REF protection appropriately at Idukki PH. 2. KSEB to replace/ repair the faulty breaker. 3. KSEB to check the PLCC equipment at New Pallam and inform the remedial measures taken to PCSC forum. KSEB Mail received on : 1. Reducing the sensitivity of REF protection of Unit # 4, 5, 6 at Idukki (Recommendat PH: - Generation wing is planning to purchase new transformer ion No.1) management relays with low impedance REF protection. Purchase procedures initiated The replacement/ repair of faulty breakers are under the consideration of Generation wing. Breakers will be replaced / repaired in a phased manner. Unit #3 breaker was replaced with available breaker from the 220kV IDMD feeder. The 220kV CBs of unit #2 and unit #3 will be replaced with in two months. 3. No abnormalities were noticed in the PLCC equipment at New Pallom station. It is kept under observation. Mail recieved on : 1. Purchase procedures is still in progress. 2. Replaced. 3. PLCC equipment Tested and found OK. Mail recieved on : 1. Even though repeated plans to have a joint inspection with M/s.ABB who is the OEM of the relay panel for replacing the relays with numerical ones, the same could not become successful. Finally, the inspection has been fixed on It has been planned to replace existing REF protection with low impedance ones after retrofitting the numerical ones of OEM. Mail recieved on : 1.Generation wing is planning ti provide low impedance REF protection by retrofitting numerical ABB make transformer management relay in the existing panel Faulty breaker of Unit3 has been replaced Completed. 3.PLCC equipments in the feeder were checked and found OK Completed. 54/II/ Sriperambudur - at 00:11 hrs SV.Chartam and 400kV Nellore- Sriperambudur line- 1 PGCIL (SR-I & SR-II) 400kV Nellore-Sriperambudur line-1 PGCIL (SR-II) to check and revise Pole Discrepancy Relay tripped on a R-phase to earth fault. (PDR) time setting appropriately based on the type of A/R 400kV Sriperambudur-S.V.Chatram line scheme being implemented at their 400 kv Sriperambudur SS. tripped at Sriperambudur end only on operation of over current protection PGCIL (SR-II) Yet to be informed 54/III/3 Tripping of 400 kv Kalvindapattu- Vallur line at 14:59 hrs R-phase to earth fault had occurred in line. Auto reclose attempt is unsuccessful/ auto-reclose could not be established from provided DR/ EL. PGCIL (SR-II) to furnish a report on the tripping event detailing the reasons for unsuccessful A/R operation at Kalvindapattu end, and the remedial action taken to restore A/R to normalcy. PGCIL (SR-II) Yet to be informed Others Page 14 of 21

23 51/II/ kV Vallur-Alamathy Line-2 got NTECL, Vallur to furnish a report detailing the reasons for maloperation NTECL TANTRANSCO mail received on : Alamathy- at 22:42 hrs of Vallur end relays for a fault on Alamathy-Tiruvalam tripped from Vallur end during failure of Tiruvalam line-1 Y-phase LA in 400kV Alamathy- line-1, and remedial measures taken to PCSC forum. In the report, and 400kV Tiruvalam line. Protection at Vallur end their preparedness for implementing line differential protection on Alamathy-Vallur line-2 tried for an auto-reclose and gave a 3 phase trip. Vallur-Alamathy lines may also be indicated. 3Ф Trip at 400kV Alamathy end due to DT received from vallur end for BФ LAS bursted in Alamathy -Thiruvalam - 1 # at Alamathy end. Mail received on and : 3Ф Trip at 400kV Alamathy end due to DT received from vallur end for BФ LAS bursted in Alamathy -Thiruvalam - Line-1 at Alamathy end. 53/III/11 Ramagundam- Chandrapur line at 22:06 hrs Line tripped on Y- phase to earth fault. Line did not auto-reclose. NTPC Ramagundam to provide Auto-reclose feature for Tie- CB s also In addition to the Main-CB s. NTPC Yet to be informed 54/I/1 Complete outage of kv S.P.Koil at 17:08 hrs Station of TANTRANSCO B-phase CT failure occurred in 230 kv S.P.Koil - MAPS line-1. Busbar protection got operated at SP.Koil station. All elements except 230kV Oragadam and 230kV Kalivandapattu got tripped at 230kV S.P.Koil station. Y phase CT and support insulators also got damaged. 1.MAPS to furnish a detailed report on the tripping of SP Koil MAPS lines 1 & 2 at MAPS end with focus on the correctness of the settings of Main-I & Main-II relays (for primary & back-up protections) on both the lines. 2.MAPS to take steps to provide down-loading facility for DR & EL from Main-I & Main-II relays on all 230 kv lines emanating from MAPS. NPCIL (MAPS) Yet to be informed 3.MAPS, in co-ordination with SP Koil, to carry out PLCC end-toend testing, on SP Koil MAPS lines 1 & 2, and ensure healthiness of PLCC communication & carrier-aided protection. 4.MAPS to put in service Auto-Reclosure feature on all four 230 kv lines emanating from MAPS by June, /II/20 Tripping of 400 kv Ramagundam Chandrapur lines 1 & 2 and HVDC Poles 1 & 2. Line-1 on at 19:16 hrs & Line-2 on at 19:26 hrs Line-1 tripped at 19:16:01 hrs on B-E fault, but auto-reclosed only at Chandrapur end. Line-2 tripped at both ends on B-E fault at 19:26 hrs. HVDC Poles 1 & 2 were tripped at 19:26 hrs due to AC under-voltage on South-Bus. NTPC-Ramagundam to properly configure A/R functionality at NTPC RSTPS end as per the agreed logic for the faults on 400 kv (Ramagundam) RSTPS Chandrapur D/C line, and furnish an action taken report to PCSC forum on the correctness of its operation. Yet to be informed Miscellaneous 34/I/6 400/220 kv ICT-1 & 2 at MUNIRABAD As reported directional over current relay of ICT s operated due to snapping of line jumper in 220kV Lingapur line. 1. Bus bar protection shall be provided by asset owner ( i.e ). 2. Settings for main distance protection & Overcurrent protection shall be examined and reviewed. 3. Time synchronization of the Substation shall be ensured. / PGCIL (SR-I) Mail recieved on (): 1. has taken action to provide bus bar protection to 220kV buses. 2. Over current relay Settings of ICTs to be reviewed by PGCIL. Mail received on (): Initial Tendering stage Mail recieved on : Detailed estimate prepared for taking up the work. CEE, Transmission Zone, Gulbarga will take up necessary procurement and further execution from side. 2. Complied with as per PGCIL (SR-I) RVMD , which stated (with ) Page 15 of 21

24 2. Complied with as per PGCIL (SR-I) RVMD , which stated that "Relay settings of all the stations in SRTS-1 were derived as per Ramakrishna Commettee recomendations and implemented." 3. from side. 40/II/3 Tripping of 400 kv TALAGUPPA HASSAN line at 13:38 hrs On account of R-phase to earth fault, line tripped at Hassan end due to operation of distance Zone-2 and nonreceipt of carrier. From D.R of Talaguppa end it is observed that fault had occurred in Yphase. 1. PGCIL and to ascertain the reason for the phase discrepancy in the relay operation and take suitable remedial measures. 2. to check the PLCC operation at Talaguppa end and submit the report to the PCSC forum. PGCIL (SR-II)/ Mail recieved on : End to end testing of PLCC has been done and problem in the PLCC is atttended. Mail received on () & : End to end testing of PLCC has been done and problem in the PLCC is atttended. Phase discrepancy in the relay operation is to be checked jointly. (with ) Mail recieved on from PGCIL (SR-II): Problem is in identification of phases at Talguppa end. To be rectified by M/s. Mail recieved on from : The matter is reffered to the concerned Operation and maintance wing to set right the mismatch of phases in 400kV Talaguppa-Nelamangala and Talaguppa-Shantigrma lines at Talaguppa in cordination with PGCIL. 42/II/18 Multiple tripping at Raichur TPS of KPCL at 06:36 hrs 400kV Raichur TPS-Raichur(PG) line- 1&2, 400kV Raichur-Mahboobnagar, Unit#7 and ICT-2 at RTPS tripped during the incident. B phase to earth fault had occurred in 400kV Raichur TPS-Raichur line-1 1. KPCL to review REF setting (DMT or IDMTL) for unit-7 by first week of April, 2015 and inform the same to PCSC forum. 2. TSTRANSCO to furnish Mehaboobnagar s DR and EL and the reasons for distance relay operation at their end within a week s time. 3. PGCIL (SR-I) to rectify the issues relating to A/R operation, relay reach (Z2), reverse reach (Z4) and SOTF auxiliary contacts within a week s time, and submit the actions taken to PCSC forum. KPCL/ TSTRANSCO/ PGCIL (SR-I) 1. Yet to be informed by KPCL Mail received on from TSTRANSCO: It is found that the main-2 ABB make REL316 type distance relay was defective and same was replaced with MICOM P444 by M/s.PGCIL on After replacement of main-ii, DR can be extracted from this relay. For EL in to service, some field winding is pending which is being taken up in this month. -- Complied with 3. PGCIL mail recieved on : End to end PLCC tunning carried out. (with KPCL) PGCIL (SR-I) RVMD : Relay settings of all the stations in SRTS-1 were derived as per Ramakrishna Commettee recomendations and implemented. - Complied with. Page 16 of 21

25 44/I/3 Tripping of Unit 1 at NCTPS Tripping of Unit 1 at MEPL Tripping of Unit 1 at Krishnapatnam at 19:13 hrs at 19:13 hrs at 19:17 hrs ID Fan trip Coal Mill tripped Generator Protection operated 1. All Tripped units, viz., Krishnapatinam, MEPL, Raichur, NCTPS to submit a detailed report on this event including the remedial measures taken to PCSC forum. 2. KPCL to check the excitation system of Unit 8 of RTPS, and submit the remedial measures taken to PCSC forum. KPCL/ MEPL/ APGENCO/ TNEB TANGEDCO vide their mail dated informed that as per the discussion and recommendation of 44th meeting of PCSC held on , a time delay of 2 Sec had been introduced for the above tripping for all the ID fans at NCTPS-II. MEPL vide their mail dated informed that they had implemented 2 seconds delay for under voltage tripping of all Drag Chain Feeder Conveyors. And this has been done for both the Units. APGENCO letter dated : The unit not tripped on Generator protection but tripped on Economiser inlet flow protection consequent to tripping of TDBFP on lube oil pressure low.before tripping, dip in voltage was observed in the LT system which caused tripping od lube oil pumps.after the incident,changeover scheme on under voltage of LT System was reduced from 80% with 2 sec delay to 40% with 200msec delay (with KPCL, APGENCO) Tripping of Unit-8 at RTPS at 19:19 hrs Tripped on Overvoltage. 44/II/6 Multiple tripping at Vemagiri substation of APTRANSCO at 10:04 hrs 400kV Vemagiri-Vijayawada lines - 1&3, 400kV Vemagiri-Gautami line-2, 400kV Vemagiri-Konaseema line-2 and 400/220kV ICT-2 at Vemagiri tripped during the incident. Triggering incident was failure of B-phase L.A in 400kV Vijayawada-Vemagiri line-1 at Vemagiri end. 1. PGCIL (SR-I) to enable Auto reclosure feature at Vijayawada end. 2. PGCIL (SR-I) to check distance relay settings for Vijayawada Vemagiri line-3, and furnish a compliance report to PCSC forum. PGCIL/ APTRANSCO PGCIL Mail received on : 1. For Vijayawada - Vemagiri - 3 feeder A/R at Vijayawada end is in service and relay settings were revised and implemented as per Ramakrishna committee recommendations. 2. For Vijayawada - Vemagiri - 1 feeder (Asset belongs to APTRANSCO), A/R relay is not envisaged. APTRANSCO has to carryout the wiring/programming in Main-1 protection OR to provide seperate A/R Relay. (with APTRANSCO ) APTRANSCO mail dated on : AS maintenance being carrired out by PGCIL(SR-1), the required relay replacement (wiring/programming) may also be carried out by PGCIL(SR-1). 45/I/2 Complete outage of MEPL power at 20:38 hrs station Y phase CT failure at MEPL led to tripping of 400kV NPS-MEPL, 400kV SEPL-MEPL line and Unit-2 at MEPL. Uni-1 was not in service at the time of tripping 1. MEPL to ensure healthiness of all CT s by carrying out Tan Delta and DGA tests wherever necessary. 2. MEPL to take suitable action to correct the operation of tie- CB Bay Control Unit that caused LBB/ BBP operation. 3. PGCIL (SR-1) to carry out end-to-end PLCC testing in coordination with MEPL and ensure that carrier-aided protection on MEPL NPS line is in healthy condition. 4. SEL to properly time-coordinate their Over Current phase and Earth fault relays in consultation with MEPL. MEPL/ PGCIL (SR- I)/ SEL MEPL vide their mail dated : informed the following 1. Tan Delta Testing of winding and DGA of Insulating Oil for all CTs was carried out and found to be normal. -- Completed 2. Could not find any problem during internal checks hence we are in touch with ABB for rectification work. Will be done by the end of 15th Oct' Completed 3. End to end testing of Carrier signals was carried out and found them healthy Completed 4. Yet to be informed by SEL ---- (with SEL) 47/I/2 Complete outage of Krishnapatnam TPS at 18:20 hrs As per FIR submitted, CT damage observed in Chitoor-Main bay (404). Main breakers connected to bus-1 (401, 1. APGENCO to furnish to PCSC forum (i) A3-size Single Line Diagram of SDSTPS, and (ii) the sequence of events with time stamp showing the protection that opened Tie-CB (405) at APGENCO/ PGCIL (SR-I) APGENCO letter dated : 1.SOE and SLD are attached. The DR of 405 CB is not generated during the incident. Now the problem is identified and rectified. with PGCIL(SR-I) Page 17 of 21

26 TPS Main breakers connected to bus-1 (401, 404, 407, 410) got tripped on operation of bus bar protection. Unit-1 tripped on operation of MFT. Unit-2 was not in service stamp showing the protection that opened Tie-CB (405) at SDSTPS. 2. APGENCO to review STUB/TEED protection in all dias at SDSTPS and ensure that they are configured for instantaneous operation. 3. APGENCO to properly configure the STATE of the tripping events so that they get recorded appropriately like TRIP/ OPERATED in their corresponding Event Loggers. 4. APGENCO to ensure time sync of all DR s and EL s at SDSTPS. 5. PGCIL (SR-I) to provide line differential protection for 400 kv NPS Nellore-PG lines 1 & 2. the incident. Now the problem is identified and rectified Completed 2.All the 3 lines i.e CHTR-2, MNBL-I & II tripped in zone protection. The fault was in Blind zone i.e P2 side of CT, where it was covered under Bus fault by the time fault moved on to P1 side when the fault comes under STUB/TEED zone after 330msec all the feeders expect CHTR-1 tripped in Zone-II and total fault persisted for 500msec before the 405 TIE CB opens and clear the fault. As a remedial the STUB protection operation also checked and found OK Completed 3.The Time Sync was missed on the day and found there was problem with LAN Timer same was rectified. Now found OK Completed 4.Now the DR Time scale changed to 1 sec for Pre fault and 3 sec for Post fault and STATE of events are corrected wherever found wrong/or misguiding during analysis completed. 5. PGCIL-SR1 RVMD : Procurement of differential protection for 400kV NPS-NLR D/C and 400kV RCR-RTPS-D/C is under tendering. PGCIL-SR1 RVMD : The proposal for procurement of Line differential Protections for 400kV Raichur - RTPS-1 & 2 and 400kV Nellore - NPS - 1 & 2 lines has been approved and tender is under technical evaluation 47/II/7 Tripping of 220kV Kadra-Karwar lines at - 1&2 and 220kV 11:44 hrs Kaiga-Kadra line 220kV Kadra-Karwar lines-1&2 tripped on earth fault in B-phase in zone-2. Kaiga-Kadra line tripped at Kaiga end only on operation of directional eath fault protection. 1. / KPCL to see the possibility of implementing Weak Infeed logic with Echo feature enabled by Under Voltage (27) element on Kadra-Karwar lines 1 &2, and implement the same if feasible. 2. NPCIL to time-coordinate Kaiga s DEFR settings with (i) Zone- 2 settings at Kaiga, and (ii) primary protections of the lines emanating from Kadra and Kodasalli. / KPCL/ NPCIL (KAPS) Mail recieved on from : Availability of week end infeed with eco feature to be confirmed by SEE,RTC,Hubli 3. KPCL to ensure time-sync of EL s, and healthiness of the Fault Locators at Kadra. 49/II/11 Tripping of 400/220 kv ICT-2 at Kurnool Substation and 400kV Kurnool- Srisailam line at 14:31 hrs 400kV Kurnool-Srisailam line - distance protection zone-2 had operated at Srisailam end. However from DR, R- phase to earth fault and zone-2 start were observed. Breakers at Kurnool end tripped on direct trip receive from Srisailam end. 1.TSGENCO in coordination with APTRANSCO to carry out endto-end testing of PLCC channels by on 400 kv Srisailam Kurnool S/C line and 400 kv Srisailam Sattenapalli D/C line. 2. TSGENCO and APTRANSCO to make A/R functional on 400 kv Srisailam Kurnool line. ICT-2 Main-CB tripped due to 3. TSGENCO to resolve configuration problems with the newly operation of bus bar protection, and Tie- commissioned relays at Srisailam LB so that unwarranted DT CB tripped due to DT receipt from sending to remote ends is addressed. Srisailam TSGENCO/ APTRANSCO TSGENCO mail received on : 1. TSGENCO in coordination with APTRANSCO, PLCC end to end testing completed for Srisailam- Kurnool S/C line and DT Send/ Receive & Carrier Send/ Receive Signals are found normal Completed. 2. Auto- reclose was disabled at Srisailam end for SSLM- KNL feeder (As per the settings given by Systems Protection/ TSTRANSCO). The feeder contains XLPE cable & GIS Completed. 3. TSGENCO intimated to M/s ABB India Ltd. Service Engineer will come and resolve the configuration problems APTRANSCO mail received on : 1. In coordination with the TSGENCO end to end PLCC Channels and carrier aided protection schemes testing was carried out and found (with TSGENCO) Page 18 of 21

27 satisfactory Completed. 50/I/2 Complete outage of TPCIL power station at 06:02hrs Running units at Thermal Powertech power Station tripped due to tripping of 400kV Nellore pooling station (NPS)- TPCIL line and 400kV Nellore pooling station (NPS)-ECC line 1.PGCIL (SR-I) to furnish Action Taken Report on the findings of OEM on relay mal-operation at NPS end on 400 kv NPS NCCK line to PCSC forum. 2. PGCIL (SR-I) to appropriately configure Station Event Logger at NPS to record events at msec interval. 3. PGCIL (SR-I) to carry out PLCC end-to-end testing in coordination with TPCIL for 400 kv NPS TPCIL line. 4.PGCIL (SR-I), MEPL, SEL, TPCIL & NCC to take steps to provide line differential protection at their respective ends on all 400 kv lines (except Gooty line) emanating from Nellore Pooling Station, and furnish an action plan to implement the same. PGCIL (SR-I), MEPL, SEL, TPCIL, NCC PGCIL (SR-I) mail received on : 1. The firmware of REL670 is being upgraded Completed. 2. The recording of events in msec interval is being taken up with OEM. Henceforth, for analysis purpose, we will provide larm list which has msec time stamp Completed. 3. End to end testing of PLCC code transmision and tuning of channels carried out Completed. 4. Procurement of differential protection for 400kV NPS-NLR D/C and 400kV RCR-RTPS-D/C is under tendering. The legends modified in Event/alarm list. Provision of diff. rel;ay for all short lines emanating from NPS is being taken up with our corporate PGCIL-SR1 RVMD : The proposal for procurement of Line differential Protections for 400kV Raichur - RTPS-1 & 2 and 400kV Nellore - NPS - 1 & 2 lines has been approved and tender is under technical evaluation 50/II/8 Gooty- Nelamangala line at 00:20 hrs R-phase to earth fault had occurred in Line. Line did not auto-reclose from both ends. It was mentioned that Y&B pole breakers at Neelamangala tripped on operation of pole discrepancy and backup impedence protection for line reactor got operated. 1. For Gooty Nelamangala line, PGCIL (SR-I) and to provide 3-ph trip logic at their respective ends upon detection of PLCC link failure during dead-time of A/R operation. 2. PGCIL (SR-I) to make GPS functional at Gooty SS, and ensure time-sync of various DR s and EL s with it (GPS). 3. PGCIL (SR-I) / to furnish reason for the operation of Backup impedance protection of the line reactor at Nelamangala end and the remedial measures taken to PCSC forum. PGCIL (SR-I) / 1. PGCIL RVMD : A/R blocked due to failure of PLCC link. The defective PLCCcards replaced at Neelamgala end. PGCIL RVMD : A/R blocked due to failure of PLCC link. The defective PLCCcards replaced at Neelamgala end. End to end testing of PLCC carried out and PLCC link is healthy Gooty end Time syc unit is replaced with new one and commissioned Completed. 3. Yet to be informed by /II/11 Neyveli TS2- Pugalur line at 4:01 hrs Line tripped on operation of over voltage protection at Pugalur end. However from DR it was observed that the voltages were below the O/v stg-1 threshold limits 1. NLC to configure DT receipt event from Pugalur for triggering DR and EL at NLC TPS II. 2. PGCIL (SR-II) to check drop-off to pick-up ratio of OVR relay at Pugalur and configure its operation as per SRPC provided OVR gradings. PGCIL (SR-II)/ NLC NLC mail received on and : Recommended configuration of DR/EL will be done during shut down of feeder NLC mail dated on : Scheduled to take up the activity on /II/6 Sattenapalli- Vijayawada line at 3:01 hrs Line tripped due to operation of over voltage protection at Vijayawada end and Direct Trip was received at Sattenapalli end 1. PGCIL (SR-I), in co-ordination with APTRANSCO, to address PGCIL (SR-I)/ the problem with CB at the earliest opportune time. APTRANSCO 2. APTRANSCO to take steps to replace the faulty Event Logger at Vijayawada (Nunna) SS. PGCIL mail received on : Being pursued with APTRANSCO APTRANSCO mail dated on : AS maintenance being carrired out by PGCIL(SR-1), the required relay replacement (wiring/programming) may also be carried out by PGCIL(SR-1). Page 19 of 21

28 PGCIL RVMD : 1. The CB problem has been attended by POWERGRID by using OEM M/s BHEL services & POWERGRID's O&M spares Completed. 2. Being pursued with APTRANSCO to replace the faulty Event Logger at Vijayawada (Nunna) SS /I/8 Complete outage of 400kV NTPL station and CEPL Stations at 01:36 hrs Running Units at NTPL and Coastal NTPL and PGCIL (SR-II) to furnish compliance report of the Energen power station got tripped due to recommendations given by PSAG-15 Committee that held its tripping of evacuating lines. meeting on April, 2016 at NTPL, Tuticorin. PGCIL (SR-II)/ NTPL NTPL mail received on : All General Recommendations will be done in the second week of June Complied by NTPL. Yet to be informed by PGCIL (SR-II) [with PGCIL (SR-II)] 53/I/5 Complete outage of kV Hoody at 12:42 hrs substation of 400kV Hoody-Nelamangala line-1&2, 1. to configure the Auto-Reclosure (A/R) scheme at / 400kV Hoody-Kolar line-1&2, 400/220kV ICT-2 at Hoody tripped Hoody end for all lines emanating from Hoody end in such a way PGCIL (SR-II) that in the event of occurrence of faults during A/R dead-time, (i) during the incident. ICT-1&3 were hand it should immediately give a 3-ph trip, and (ii) A/R should go into tripped after the incident. lock-out state, i.e., it must not reclose after the elapse of deadtime of A/R. 2. As regards over-reaching of Kolar and Nelamangala end relays for the fault on 400 kv Hoody Kolar line-2, and PGCIL (SR-II) are recommended to modify the Z1B settings of the relays used (7SA522) suitably so that they operate with a Zone-2 time delay. 3. to check the ICT s back-up (high-set) protection settings, and ensure that they operate with a time delay of 100 msec. 4. to take steps to replace the solid state relays at Hoody end on Hoody-Nelamangala lines 1 & 2 with numerical relays at the earliest. Mail recieved dated : 1. Incorporated. --- Completed. 2. Yet to be informed. 3. With the existing electromechanical relays, it's not possible to add time delay of 100 msec. However, ongoing R&M works of Hoody included complete ICT1 and ICT2 panel replacement having Numerical relays. 4.The solid state relays of Nelamangala-1 and Nelamangala-2 lines will be replaced by numerical relays for which relays have been identified,will be attended in a month's time. Mail recieved dated : 2. Clarification sought from OEM regarding Z1B settings,psb settings to be adopted in Seimens make distance relays. 3. ICT back up (high set settings are verified and found to be in order. --- Completed. 4.At Hoody, Solid state relays of 400kV Nelamangala 1 &2 lines are replaced by numerical relays. Now 400kV Nelamangala 1& 2 lines are provided with ABB, REL 670 and Micom P442 relays. --- Completed. only point 2 54/IV/2 Ghanapur- Mamidapalli line at 16:40 hrs Line tripped at Mamidipally end only on For the line under consideration, the following shall be carried out Direct Trip receipt from Ghanapur end by TSTRANSCO and PGCL (SR-I) in co-ordination: 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. PGCIL (SR-I)/ TSTRANSCO Yet to be informed Page 20 of 21

29 Page 21 of 21 Annexure-II

30 I Sl.No. Element Name 1 400/220 kv ICT-3 AT RSTPS Kv SATTENAPALLI - SRISAILAM Kv RAICHUR PG - GOOTY 1 Outage date/time /17:45: /17:55: /00:25: kv MAHABOOB NAGAR - RAICHUR /02:41: kv AMBEWADI - PONDA kv AMBEWADI - PONDA /220 kv ICT-2 AT HOODY kv RAMAGUNDAM - N'SAGAR 2 Remedial Measures/ Actions taken for the Critical Tripping Incidents (as on ) Revival date/time /21:30: /01:38: /22:53: /04:34: /03:09: /19:24: /23:06: /05:01: /19:37:00 Reason for Outage LV SIDE TRIPPED DUE TO LINE TRIPPED ON B-N FAULT DISTANCE PROTECTION TRIPPED ON R-PH FAULT TRIPPED ON BREAKER RCR DISTANCE PROTECTION DISTANCE PROTECTION BUSHING FLASHOVER Sender/ Receiver NTPC-Ramagundam APTRANSCO/TSGENCO PGCIL(SR-I) TSTRANSCO/ /GOA(SR) /GOA(SR) Remedial Measures/ Actions taken APTRANSCO:Momentary Fault. B -N FAULT NTPC/PGCIL(SR-I) kv TALAGUPPA - HASSAN /16:52:00 B - N FAULT /PGCIL(SR-II) Portion of the line in which fault occured owned and maintained by M/s. May be clarified from M/s 10 GOOTY-NELAMANGALA /16:06: /16:59:00 TRIPPED DUE TO TEMP. HIGH PROTECTION PGCIL (SR-I)/ Page 1 of 4

31 I Kv SHANKARPALLY- MAMIDIPALLY /20:58:00 R-N FAULT TSTRANSCO kv YERANDAHALLY - HOSUR /21:16: /23:05:00 B-N FAULT / TANTRANSCO TANTRANSCO: AR successful at Hosur end. After 12 secs., feeder tripped with same indications. AR lockout since fault detected within reclaim time. : 13 GOOTY-SOMANAHALLI KV RAICHUR - SHOLAPUR kv SEDAM - TANDUR kv AMBEWADI - PONDA KV RAICHUR - SHOLAPUR kv JSW TORANAGALLU-GUTTUR /23:12: /16:08: /21:52: /03:00: /22:28: /13:57: /23:40: /19:05: /00:36: /23:03: /14:14:00 TRIPPED PGCIL (SR-I) Y - B FAULT PGCIL (SR-I)/ PGCIL (WR-I) B-N FAULT / TSTRANSCO B-N FAULT / GOA TRIPPED ON B-PH FAULT PGCIL (SR-I)/ PGCIL (WR-I) MASTERTRIP JSWEL/ kv NELAMANGALA - HOODY /11:31: /11:45:00 TRIPPED AT HOODY END ONLY kv WARANGAL - BOOPALPPALLI kv KHAMMAM - N'SAGAR /20:45: /22:41: /22:01: /22:54:00 TRIPPED ON R-PH FAULT TRIPPED ON B-PH FAULT PGCIL (SR-I)/ TSGENCO PGCIL (SR-I) kv KAIGA - GUTTUR /14:18:00 TRIPPED ON R-PH FAULT KAPS/ Portion of the line in which fault occured owned and maintained by M/s. May be clarified from M/s Page 2 of 4

32 I Kv HASSAN - UPCL /12:16: /12:19:00 TRIPPED AT HSN END ONLY PGCIL (SR-II)/ / UPCL UPCL:During the tripping, at UPCL end line tripped on operation of Zone-1-Y Phase, whereas at Hassan end tripped on operation of Main-2 Zone-2 with time delay due to non-receipt of carrier signal. it is necessary to check carrier scheme for Main-1 and Main-2 at Hassan end : PGCIL(SR-II):Tripped as the relay operated for fault in Zone-2 and carrier not received from other end kv AMBEWADI - PONDA kv AMBEWADI - PONDA kv AMBEWADI - PONDA Kv VTPS - SURYAPET kv NEYVELI TS 2- SALEM kv UDUMALPET - TIRUNELVELI 2 30 HVDC TALCHER - KOLAR POLE 1 AT KOLAR kv GUTTUR - NARENDRA /21:08: /13:33: /11:20: /11:20: /16:53: /12:24: /18:56: /16:35: /18:05: /11:48: /11:49: /17:56: /15:19: /19:05: /17:53: /21:48:00 B - N FAULT / GED BUS AMDI END BUS AMDI END DT RECEIVED / GED / GED DUE TO JUMPER CUT TRIPPED AT UDUMALPET END DUE TO DC LINE PGCIL(SR-II) FAULT LOW AUR PRESSURE IN CB AT /PGCIL(SR-I) GTR END Page 3 of 4

33 I 32 HVDC TALCHER - KOLAR LINE 1 33 HVDC TALCHER - KOLAR LINE Kv PALLAKAD - TRICHUR kv SEDAM - TANDUR /220 kv ICT-2 AT GOOTY kv NEYVELI TS2- NEYVELI TS-I /230 Kv ICT-1 AT ARASUR kv AMBEWADI - PONDA Kv NCTPS - SVCTM-II /220 kv ICT-1 AT GUTTUR kv SALEM - UDUMALPET kv MADURAI - UDUMALPET /02:18: /15:27: /16:04: /14:49: /09:08: /12:07: /12:07: /16:35: /16:35: /17:53: /17:53: /16:42: /17:02: /19:53: /14:54: /15:02: /18:21: /11:27: /19:25: /19:20: /11:45: /12:41: /12:43:00 DUE TO DC LINE PGCIL(SR-II) FAULT DUE TO DC LINE PGCIL(SR-II) FAULT TRIPPED ON B-N FAULT DECLARED PGCIL(SR-II) FAULTY 220KV SDM BUS / TSTRANSCO DEAD BUS BAR ACTED AT PGCIL(SR-II) 220KV SIDE TO ATTEND HOT NLC SPOT FOR ARRESTING OILLEAK IN THE Y PGCIL (SR-II) PHASE BUSHING TO ATTEND FAULT /GED Y-N FAULT TANGEDCO/ TANTRANSCO TRIPPED ON Y-N FAULT DT RECEIVED FROM UDUMALPET END DT RECEIVED FROM UDUMALPET END PGCIL (SR-II) PGCIL (SR-II) Page 4 of 4

34 Page 1 of 4 Annexure-IV