SOUTHERN REGIONAL POWER COMMITTEE BENGALURU

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4 SOUTHERN REGIONAL POWER COMMITTEE BENGALURU Agenda for the 72 nd Meeting of Protection Coordination Sub-Committee of SRPC to be held on 15 th March, Introduction 2. Confirmation of Minutes of last PCSC meeting Confirmation of minutes of 71 st Protection Coordination Sub-Committee meeting held on Grid Occurrences 3.1 Grid Disturbances (GD), Grid Incidences (GI), and trippings due to failure of Autoreclosing (A/R), and mal-operation of PLCC equipment that occurred during the period January February, 2018 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. (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/ furnish 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 within 24 of occurrence of the same to SRLDC/ SRPC: (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 letters (i) No. SRPC/ SE-III/ PCSC/ 2018/ dated , (ii) No. SRPC/ SE-III/ PCSC/ 2018/ dated , and (iii) N. SRPC/ SE-III/ PCSC/ 2018/ dated Non-compliance in this regard would be discussed in the meeting. 4. Submission of Reports/Compliance by Constituents 4.1 Status of implementation of pending Protection Coordination Sub-Committee (PCSC) Recommendations The status of implementation of pending PCSC recommendations (up to 71 st PCSC meeting) is given at Annexure-II. The latest status on the same may please be sent latest by Agenda for the 71 st Meeting of PCSC scheduled to be held on 31 st January, 2018 Page 1

5 4.2 Remedial measures for "Transmission Elements under Forced Outage" The Constituents are requested to furnish the remedial measures/ action taken by them for the tripping events as circulated vide our s. (Annexure-III) The tripping events are based on the daily reports at SRLDC website 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 Secretariat. The sought status for the months of January, 2018 is awaited from the following SR-Constituents: KPTCL, TANGEDCO, TANTRANSCO, KSEBL, PED, PGCIL (SR-I) & TPCIL 5. TSTRANSCO s SPS proposals at 220kV Sivarampally and 220kV Gachibowli substations TSTRANSCO vide their letter dated (Annexure-IV) has proposed for implementation of SPS schemes at 220kV Sivarampally and 220kV Gachibowli substations to avoid cascade tripping of the following lines during contingency: kV HIAL Sivarampally kV Mamidipally Sivarampally kV Shankarpally Gachibowli feeders kV Shankarpally Gachibowli feeders-2 The effectiveness & appropriateness of the schemes will be discussed during the meeting. TSTRANSCO and SRLDC are requested to present their case so that a call can be taken w.r.t. their implementation. 6. PMS: Protocol on using PDMS You are kindly aware that Protection Management System (PMS) under implementation for Southern Region consists of two parts, viz., (i) Web-based Protection Data Management System (PDMS), and (ii) Desktop-based Protection Setting Calculation Tool (PSCT). While PSCT is the Calculation software for carrying out various studies (load-flow, short-circuit, transient stability, protection settings coordination), PDMS is an Asset Management Tool for maintaining information on relay attributes and settings. PDMS is a workflow driven webbased system with role-based access control. In the meeting, protocol on using PDMS will be presented. Agenda for the 71 st Meeting of PCSC scheduled to be held on 31 st January, 2018 Page 2

6 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 It is informed that the 73 rd meeting of PCSC will be held on 26 th April, 2018 (Thursday) from 10:30 onwards in the Conference Hall of SRPC Secretariat, Bengaluru. ***** Agenda for the 71 st Meeting of PCSC scheduled to be held on 31 st January, 2018 Page 3

7 Grid Occurrences - 72 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 Complete outage of 230kV Mywadi SS of TANTRANSCO Complete outage of 400kV UV Konda Substation of APTRANSCO Complete outage of 220kV TK Halli, Kadakola, Chamarajanagara and Maduvinahally substation of KPTCL Complete outage of 220kV Sedam, Shahapur, Shahabad, Kapanoor, Humnabad and Halabarga Stations of KPTCL at 2: at 4: at 12: at 17:46 Bus tripping got extended to 230kV Bus at 230kV Mywadi substation due to actuation of LBB protection during a Y-phase to earth faultin 230kV Mywadi- Kadamparai-2 feeder. All 230 feeders (10 Nos) and 400/230kV ICT LV s-1, 2 & 3 got tripped during the incident. 400kV UV Konda- Jammalmadugu line-1 tripped at 4:48 due to Y- phase to ground fault at both the ends. 400kV UV Konda Jammalmadugu line-2, Mahabubnagar line-1 and 2 were in open condition due to high voltage. After the tripping of 400kV UV Konda- Jammalmadugu line-1, 400/220kV ICT #1,2,3 and 4 at 400kV UV Konda were hand tripped due to loss of evacuating lines. Snapping of B phase Jumper in 220kV Bastipura-Kadakola line-1 resulted in tripping of the line. 220kV Bastipura-Kadakola line-2 also got tripped during fault in line-1. Due to tripping of above lines bus shutdownoccured at TK Halli, Madhuvanahally, Chamarajanagara and Kadakola stations due to overloading of connected lines. High resistance fault occurred in 110kV SedamChittapur line near Sedam end. Line DEF operated and backup OC protection of 100MVA transformer operated at Sedam end. But line breaker and transformer HV breaker didn t open due to problem in trip circuit. This resulted in cascade tripping of upstream feeders and power supply was lost to six 220kV stations of KPTCL GD-1 Gen Loss: 180MW Load Loss: 450MW Load Loss: 410MW GD-1 GD-1 GD-1 Grid Occurrences to be discussed in the 72 nd Meeting of PCSC scheduled to be held on 15 th March, /4

8 Annexure-I 5 Complete outage of 230kV Hosur SS of TANTRANSCO at 01:41 Triggering incident was failure of Y phase HV CT in 100 MVA Auto Transformer 3. Bus Bar Protection operated and all the 230kV feeders &Auto Transformers connected in 230kV Bus got tripped. Load Loss: 174 MW GD-1 II. Details of Grid Incidents: Sl. No. Details of Event Date &Time Reason Category Multiple Tripping at 400kV Raichur TPS. Tripping of HVDC Talcher-Kolar pole- 1. Tripping of 400kV Srisailam-Narnoor line Tripping of 400/220kV Hoody ICT-3 and 400 kv Kolar-Hoody ckt at 17: at 19: at 07: at 02: at 01: at 17:42 400kV Raichur TPS Munirabad line tripped on operation of Zone-1 protection due to Y-N fault. 400kV RTPS- Raichur PG-1&2 tripped at RTPS end only on operation of stub protection On , pole-1 tripped due to burning of one of the Series Reactor in R- Phase of Pole-1. ESOF signal was received at Kolar. On Pole-1 tripped due to operation of Valve Cooling Differential Protection at Talcher end. Emergency switch off (ESOF) was received at Kolar. Tripped on operation of over-voltage protection at Srisailam and direct trip was received at Narnoor Triggering incident was failure of Y-phase lightning arrestor of 400kV Hoody-Kolar ckt-2 at Hoody end. and 400kV Kolar Hoody Circuit-2 tripped on operation of distance protection. At the same time 400/220kV, 500MVA ICT-3 at Hoody also tripped on earth fault protection. 5 6 Tripping of 400kV Neyveli TS2-Neyveli TS2 Exp-1 and 400kV Neyveli TS2-Pugalur line Tripping of 400/220 kv Vemagiri ICT at 03: at 07:00 Triggering incident was B-phase to earth fault in 400kV Neyveli TS2-Neyveli TS2 Exp line-1 due to failure of insulator near tower no.1 at NLC TS2-Exp end. The line has a differential protection which resulted in 3 phase trip at both ends. At the same time over-voltage protection got operated in 400kv Neyveli TS2- Pugalur line-1 at NLC TS-2 end and direct trip was received at Pugalur Tripped due to mal operation of B phase instantaneous over current relay. 400kV Vijayawada-Vemagiri also tripped due to B-phase to earth fault Grid Occurrences to be discussed in the 72 nd Meeting of PCSC scheduled to be held on 15 th March, /4

9 Annexure-I Tripping of 400kV KTPS VI-Khammam line-2 765/400kV ICT#1 and ICT#2 at Vemagiri. Tripping of HVDC Gazuwaka pole at 12: at 18: at 18: at 11: at 06:38 On both the days line got tripped at KTPS end and was holding from Khammam. At KTPS end breakers got tripped due to operation of 96 B lockout relay Tripped due to mal-operation of Group A&B relays due to DC earth fault while carrying out testing of new 400kV CB timings Due to fault in 220kV line, ICT-1 at Gazuwaka got tripped due to directional OC high set. Since tertiary of ICT-1 was feeding the auxiliary supply to pole-1, tripping of ICT-1 led to the tripping of pole-1 due to loss of auxiliary supply 11 Tripping of HVDC Gazuwaka pole at 00:23 Pole 2 tripped due to the activation of WA2 Ferro Resonance Detected" in East side Multiple Tripping at 220kV Gajwel substation Tripping at 400kV Raichur PG -Raichur TPS line 1 and 2 Tripping of FSC of Both circuits of Jeypore - Gazuwaka due to Ferroresonance at 16: at 17: at 16:02 B phase to earth fault due to earth rod not removed after maintenance work, 220kV Busbar-1 protection acted. All elements connected to Bus-1 tripped. 220/132kV, 160MVA ICT-2 connected to Bus-2 also tripped due to Over Load. While carrying out bus bar scheme checking, RTPS-Raichur PG 1 and RTPS- Raichur PG 2 lines tripped at Raichur PG end. Direct Trip (DT) was received at RTPS end. Bus-1 was under shutdown. FSC of both circuits of 400kV Jeypore- Gazuwaka got bypassed due to ferroresonance kV Gooty NPS Ckt at 16:30 Line tripped due to Tie CB LBB relay maloperation. Grid Occurrences to be discussed in the 72 nd Meeting of PCSC scheduled to be held on 15 th March, /4

10 III. Details of Trippings due to Failure or Non-operation of Auto-Reclose: Annexure-I Sl. No. Element Date & Time Reason 1 Tripping of 400kV YTPS- BTPS line at 6:17 Line tripped on B-ph to earth fault. Line did not autoreclose Tripping of 400kV Vemagiri-Simhadiri line-1 Tripping of 400kV Sriperambadur-Chitoor line-1 Tripping of 400kV Cudappah-Chitoor line at 05: at 01: at 16:03 B-phase to earth fault had occurred in line. At Simhadri end relay sensed fault in Zone-2 in B phase and tripped in zone-2 time due to non-receipt of carrier from Vemagiri. At Vemagiri, auto-reclose was attempted and same was un-successful. B-phase to earth fault had occurred in line. Autoreclose was successful at Sriperambadur and autoreclose did not operate at Chittoor end leading to all breaker poles opening at Chittoor B-phase to earth fault had occurred in line. Autoreclose was successful at Chittor end & breakers at Cudappah end got tripped. After auto-reclose line was holding from Chittoor end 5 Tripping of 400kV HNPCL-K.V.Kota line at 11:46 Tripped due to R-phase to ground fault. Line did not reclose at HNPCL 6 Tripping of 400kV Hassan-Nelamangala line at 15:21 Tripped due to B-phase to earth fault. Auto-reclose attempt was un-successful at Hassan and protection at Nelamangala did not attempt auto-reclose 7 Tripping of 400kV Srisailam-Dindi ckt at 07:11 Tripped on Y-Phase to Ground fault. Auto-reclose was disabled. 8 Tripping of 400kV Nelamangala-Hassan line at 14:22 Tripped on B-phase to ground fault. Auto-reclose unsuccessful IV. Details of Trippings due to PLCC mal-operation: Sl. No. Element Date & Time Reason 1 Tripping of 400kV Mamidapalli-Dindi line at 11:29 Line tripped on Direct Trip receipt at Mamidipally end and line was in service from Dindi. 2 3 Tripping of 400kV Mamidapalli-Dindi line-2 Tripping of 400kv Dichipally Nizamabad line at 14: at 12:25 Tripped at Dindi end only on Direct Trip received indications. DT was sent from Mamidipally end Line tripped at Dichipally end only due to spurious DT received at Dichipally. No counter increment was observed at Nizamabad end. Line was holding from Nizamabad end. ***** Grid Occurrences to be discussed in the 72 nd Meeting of PCSC scheduled to be held on 15 th March, /4

11 Status of Implementation of PCSC Recommendations as on (up to 71st Meeting) Meeting No / Index Details of Event Date & Time Reason PCSC Recommendations Utility responsible for Implementation Status of Implementation of PCSC Recommendations Remarks Multi-Utilities 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 KPTCL). 2. Settings for main distance protection & Overcurrent protection shall be examined and reviewed. 3. Time synchronization of the Substation shall be ensured. KPTCL/ PGCIL (SR-I) KPTCL Mail dated : 1. KPTCL has taken action to provide bus bar protection to 220kV buses Over current relay Settings of ICTs to be reviewed by PGCIL KPTCL Mail dated : 1. Initial Tendering stage (with KPTCL) KPTCL Mail dated on : 1. Detailed estimate prepared for taking up the work. CEE, Transmission Zone, Gulbarga will take up necessary procurement and further execution with PGCIL (SR-I) PGCIL (SR-I) Mail dated : 2. Relay settings of all the stations in SRTS-1 were derived as per Ramakrishna Commettee recomendations and implemented" --- Completed. KPTCL Mail dated : 1) & 3). DPR is approved. Tender is to be called by CEE,TZ Kalaburgi KPTCL informed that Tenders for providing BBP would be called in Jan-Feb, 2018; Supply of the same is targeted by September, 2018; Erection & Commissioning is targeted by January, PGCIL (SR-I) informed that time-synchronization of 220 kv side is in place. --- Completed. 40/II/3 Tripping of 400 kv TALAGUPPA HASSAN line at 13:38 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 KPTCL to ascertain the reason for the phase discrepancy in the relay PGCIL (SR-II)/ KPTCL Mail recieved on : operation and take suitable remedial measures. 2. KPTCL to check the PLCC operation at Talaguppa end and submit the report to the PCSC forum End to end testing of PLCC has been done and problem in the PLCC is atttended. --- Completed Mail received on (KPTCL) & : 1. Phase discrepancy in the relay operation is to be checked jointly End to end testing of PLCC has been done and problem in the PLCC is atttended. --- Completed Mail recieved on from PGCIL (SR-II): 1. Problem is in identification of phases at Talguppa end. To be rectified by M/s KPTCL Mail recieved on from KPTCL: 1. 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. --- KPTCL Mail dated : 1. Shut downs have be planned.pgcil coordination is required KPTCL informed that the required work in proposed to be carried out on HV (400 kv) side. Tedners for the same would be called by February, 2018, and the work is targeted to be completed by August, Page 1 of 34

12 47/I/2 Complete outage of Krishnapatnam TPS at 18:20 As per FIR submitted, CT damage observed in Chitoor- Main bay (404). 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 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 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. 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 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. PGCIL-SR1 RVMD : 5. Procurement of differential protection for 400kV NPS-NLR D/C and 400kV RCR-RTPS-D/C is under tendering. [with PGCIL (SR-I)] PGCIL-SR1 RVMD : 5. 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 PGCIL (SR-I) Mail dated : PGCIL: On LDP relays commissioned in place of Main-1 distance relay in 400kV NPS-Nellore line-2 & In line-1 installation of LDP relay is planned in Dec-2017/Jan PGCIL (SR-I) informed that LDP commissioning on both lines would be completed by February, In this regard, PCSC made it clear that the recommendation pertains to providing LDP as both Main-I & Main-II on both the lines, and asked PGCIL (SR-I) to ensure & comply with the same. Page 2 of 34

13 47/II/7 Tripping of 220 kv Kadra-Karwar lines - 1&2 and 220kV Kaiga-Kadra line at 11:44 220kV Kadra-Karwar lines-1&2 tripped 1. KPTCL/ 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. KPTCL/ KPCL/ NPCIL (KAPS) KPTCL Mail recieved on : 1. Availability of week end infeed with eco feature to be confirmed by SEE,RTC,Hubli ---. on earth fault in B-phase in zone-2. Kaiga-Kadra line tripped at Kaiga end only on operation of directional eath fault protection. 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. 3. KPCL to ensure time-sync of EL s, and healthiness of the Fault Locators at Kadra. NPCIL (KGA) Mail recieved on : 2. The 200 ms Definite time DEFR element in both Kaiga Kadra and Kaiga Kodasally lines were disabled. IDMT DEFR is retained. The 200 ms Definite time back up o/c element in both Kaiga Kadra and Kaiga Kodasally lines were disabled. IDMT is retained. --- Completed. Status received vide KPCL mail dated & : 1. Since PT blasted (B phase) at Karwar end, resistive over reach occurred. hence Backup protecion operated at Kadra end (zone-2 not sensed) Completed 3.Newly commissioned micom P444 relay time synchronised with GPS Completed. KPTCL Mail dated : 1. Week end infeed logic will be enabled in the new numerical relays supplied to Karwar under R&U during retrofitting works KPTCL informed that since the line is a double circuit, there may not be need for implementing Weak Infeed logic with Echo feature at Karwar end. However, the same would be looked into w.r.t. the newly commissioned NR's at Karwar, and final action taken would be informed by March, [with KPTCL] 50/I/2 Complete outage of TPCIL power station at 06:02 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)- NCC line 1.PGCIL (SR-I) to furnish Action Taken Report on the findings of OEM on relay maloperation at NPS end on 400 kv NPS NCC 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. 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. relay for all short lines emanating from NPS is being taken up with our corporate 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) RVMD : 4. 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 --- PGCIL (SR-I) Mail dated : 4. LDP relays procurement is under process. Procurement will be completed by Feb TPCIL has to give written confirmation for LDP relay procurement. For want of written confirmation from TPCIL, PGCIL approving authority has withheld the LDP proposal. 4. PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL to complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit written confirmation to PGCIL (SR-I) by PGCIL (SR-I) assured that with receipt of above confirmation from TPCIL by Dec, 2017, they would be able to complete the work by FEbruary, APTRANSCO informed that they would be able to implement LDP from their & APGENCO side by April, In this regard, PCSC forum made it clear that the recommendation is about providing LDP as both Main-I & Main-II relays on all stated lines in Nellore Complex, ans asked all stakeholders to ensure & comply with the same. Page 3 of 34

14 51/II/6 Tripping of 400kV Sattenapalli-Vijayawada at 3:01 Line tripped due to operation of over voltage protection line at Vijayawada end and Direct Trip was received at Sattenapalli end 1. PGCIL (SR-I), in co-ordination with APTRANSCO, to address the problem with CB at the earliest opportune time. 2. APTRANSCO to take steps to replace the faulty Event Logger at Vijayawada (Nunna) SS. PGCIL (SR-I)/ APTRANSCO PGCIL mail received on : Being pursued with APTRANSCO [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). 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 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). APTRANSCO mail dated : May be coordinated with PGCIL APTRANSCO mail dated : PGCIL may be requested to take necessary action APTRANSCO mail dated : 2. EL procured and drawn. Configuration to be done by Alstorm company engineer. Will be configured in four weeks. --- PGCIL (SR-I) Mail dated : 2. APTRANSCO is to replace the faulty/outdated relays & POWERGRID has to maintain the relays after retrofitting. 2. APTRANSCO informed that the recommended works would be completed in one-month period. APTRANSCO Mail dated As per the requirement of PGCIL.Event logger(bcu) with data base is configured and handed over to PGCIL/Nunna on 27 th dec 17.PGCIL is requested to take action for taking event logger (BCU) into service. 56/I/2 Complete outage of 220kV Sedam Substation of KPTCL at 15:27 220kV Sedam-Humnabad-2 tripped at Sedam on KPTCL and TSTRANSCO to take steps to provide A/R feature on 220 kv Sedam Distance protection, Zone-2. Sedam-RTPS-1 &2 lines Tandur inter-state line at their respective ends at the earliest. tripped at RTPS end only. 220kV Tandoor inter-state line was hand tripped due to incoming supply failure KPTCL/ TSTRANSCO KPTCL Mail dated : Carrier protection is to be restored. B/U OC and EF relay is to be replaced by M-II distance relay. Required materials like wave trap, [with KPTCL] M-II distance relay are already supplied. The work will be taken up on top priority through GE Ltd. --- TSTRANSCO informed that they have kept A/R in service from Tandur end. KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into service by February, Page 4 of 34

15 56/II/13 Tripping at 220 kv Gooty Substation of APTRANSCO at 16:04 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 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/ PGCIL (SR-I) 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. APTRANSCO mail dated & SRPC is requested to coordinate with PGCIL in takind necessary action. APTRANSCO mail dated & PGCIL may be requested to take necessary action APTRANSCO maild ated : 1. Cable healthiness checked and found ok. But it is proposed to replace the cable with armored cable. --Completed 2. After replacing the cable contactors will be removed so as to avoid unwarrented delays in transmitting trigging signal to the central unit. --- APTRANSCO informed that replacement of the existing cable with armoured cable and subsequent removal of cable contactors would be completed by In this regard, PGCIL (SR-I) also assured that they would render all required help from their side to complete the stated works in time. APTRANSCO Mail Dated : New armoured cable is laid from 220 kv Gooty (AP) to 400/220 kv Gooty (PGCIL) for replacing the existing cable connected to ICT- 2.PGCIL is requested to provide spare contacts from trip relays of 315 mva LV-1 and LV-2 for providing internal CB failure in busbar protection scheme. 56/III/4 Tripping of 220 kv Sedam-Tandur line at 21:52 Line tripped on B-phase to earth fault. Auto-reclose is not enabled for line. KPTCL and TSTRANSCO to fast-track providing A/R on 220 kv Sedam Tandur line, and furnish an action plan of providing the same by next PCSC meeting (PCSC-57). KPTCL/ TSTRANSCO KPTCL Mail dated : Carrier protection is to be restored. B/U OC and EF relay is to be replaced by M-II distance relay. Required materials like wave trap, M-II distance relay are already supplied. The work will be taken up on top priority through GE Ltd. TSTRANSCO informed that they have kept A/R in service from Tandur end. KPTCL informed that the works relating to put A/R in service are gonig on at their Sedam SS, and assured that it would be put into service by February, TSTRANSCO MAIL DATED : As discussed in the review meeting on , A/R is kept in service from Tandur(TSTRANSCO) end /I/1 Complete outage of 220 kv Karwar Substation of KPTCL at 11:36 Triggering incident was failure of R phase PT in Bus-1 at 1.NPCIL (KAPS) to disable DefiniteTime O/C relay, and put in its place by IDMT 220kV Karwar substation. 220kV Kaiga-Kodasalli tripped O/C relay for backup protection on both 220 kv Kaiga Kadra line and 220 kv during the incident. Also bus shut down occurred at Kaiga Kodasalli line at Kaiga end. Kadra and Kodasally stations. 2.KPTCL to put bus bar protection in service at their 220 kv Karwar SS at the earliest. 3.KPCL/ KPTCL to implement Weak In-feed Logic with Echo feature enabled by Under Voltage (27) element on Kadra Karwar lines 1 & 2. 4.KPTCL to furnish equipment failure report of the current incident to PSE&TD Division of CEA with a copy marked to SRPC. KPTCL/ KPCL/ NPCIL (KAPS) NPCIL(KGS) mail dated on & : 1.The 200 ms Definite time DEFR element in both Kaiga Kadra and Kaiga Kodasally lines were disabled. IDMT DEFR is retained. --- Completed KPTCL Mail dated : 2) Bus-bar protection panel is supplied under R&U. Replacement work will be taken up after priority Sub stations ] Weak end Infeed logic available in new relays supplied; Will be enabled During R&U works ] Equipement failure reports are being sent to CEA regularly. --- Completed [with KPCL & KPTCL] 2. KPTCL informed that the works relating to providing BBP are targeted to be completed by March, KPTCL informed that since the line is a double circuit, there may not be need for implementing Weak Infeed logic with Echo feature at Karwar end. However, the same would be looked into w.r.t. the newly commissioned NR's at Karwar, and final action taken would be informed by March, Page 5 of 34

16 57/II/9 Tripping of 400 kv Nellore (PG) - NPS line , 400 kv Krishnapatnam-Nellore (AP) at 19:05 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 over-reached 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. PGCIL (SR-I), TPCIL, MEPL, SEL, SGPL, APTRANSCO, APGENCO and SDSTPS to APGENCO/ implement line differential protection on all 400 kv transmission lines (of length PGCIL(SR-I)/ less than 50 km) emanating from Nellore PS, Nellore (PG) SS, and Nellore (AP) SS. TPCIL/MEPL/SEL/ [It may be noted here that the cut-off length of 50 km has been specified with a SGPL/ APTRANSCO view to exclude only long transmission lines]. APTRANSCO mail dated on : Issue was addressed to the concerned for necessary action. APTRANSCO mail dated on : Meeting was conducted and the relays procurement for all the loctions is under progress. APTRANSCO mail dated on & : Relays procurement for all the locations is under progress. APTRANSCO Mail dated : Technical bids opened. PQ evaluation under progress. Price bids expected to open in next week. PGCIL (SR-I) Mail dated : LDP relays procurement is under process. Procurement will be completed by Feb TPCIL has to give written confirmation for LDP relay procurement. For want of written confirmation from TPCIL, PGCIL approving authority has withheld the LDP proposal. PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL to complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit written confirmation to PGCIL (SR-I) by PGCIL (SR-I) assured that with receipt of above confirmation from TPCIL by Dec, 2017, they would be able to complete the work by FEbruary, APTRANSCO informed that they would be able to implement LDP from their & APGENCO side by April, In this regard, PCSC forum made it clear that the recommendation is about providing LDP as both Main-I & Main-II relays on all stated lines in Nellore Complex, ans asked all stakeholders to ensure & comply with the same. APTRANSCO MAIL DATED Technical & financial bids are opened. Tenders will be awarded shortly. Page 6 of 34

17 64/I/1 Complete outage of North Chennai TPS STG at 21:02 Tripping of evacuating lines due to fault led to tripping of Units TANTRANSCO and PGCIL (SR-II) to take steps to complete insulator replacement works on the 400 kv lines owned by them in Chennai area within 3 months. TANTRANSCO/ PGCIL(SR-II) Status received vide TANTRANSCO mail dated & & & : 1. All the Porcelain insulators of 400kV NCTPS-II - Vallur feeders-1&2 were replaced with Polymer insulators by Completed 2. Existing Porcelain insulators of all other 400kV feeders are being replaced with Polymer insulators in a phased manner. --- [with TANTRANSCO] PGCIL (SR-II) Mail dated : Pertaining to POWERGRID all the porceleing insulators in the polluted streches has been completed. - Completed. TANTRANSCO informed that a total of 597 insulators ahd alreeady been replaced, and the total replacement would take another 9- month period. 64/I/2 Complete outage of North Chennai TPS STG at 18:27 Tripping of evacuating lines due to fault led to tripping of Unit In this regard, TANTRANSCO was asked to furnish detailed plan of action regarding replacement of insulators on all 400 kv lines owned by them in Chennai area. TANTRANSCO MAIL DATED : Existing Porcelain insulators of all other 400kV feeders are being replaced with Polymer insulators in a phased manner. Timeline: Sep Detailed plan of action will be submitted. 64/I/3 Complete outage of North Chennai TPS STG at 21:09 Tripping of evacuating lines due to fault led to tripping of running Unit at NCTPS Stg-2 66/ II/ 5 Tripping of 400 kv Ramagundam - Dichipally line, 400kV Nizamabad - Dichipally line-1 and 400/220 kv ICT at 19:15 Triggering incident was fault in 400kV Nizamabad GIS 1. TSTRANSCO/ NTPC to adopt proper Zone-2 time settings (say, Ramagundam NTPCend --> 500 msec; Dichipally end --> 350 msec in line with Ramakrishna Ramagundam/ Committee recommendations) on 400 kv Ramagundam Dichipally line and 400 TSTRANSCO/ kv Dichipally - Nizamabad lines respectively. PGCIL (SR-I) 2. For the 400 kv Dichipally - Nizamabad D/C line, TSTRANSCO, in coordination with PGCIL (SR-I), to carry out the following: (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) Mail dated : 1. In 400kV Nizamabad-Dichpally lines Zone-2 trip time delay of 0.35 sec was already implemented at Nizamabad end. 2. For 400kV NZB-Dichpally D/C lines PLCC commissioned with LDP relays & Line-1 tested on & Line-2 tested on found ok. --- Completed 1. It was agreed that TSTRANSCO would provide revised settings to NTPC-Ramagundam for implementation in one-week time. In this regard, PCSC forum also asked TSTRANSCO to revise their Zone-2 settings of their 220 kv & 400 kv lines in line with Ramakrishna Committee guidelines. To this, TSTRANSCO replied in affirmative and assured that they would comply with the same by January, TSTRANSCO MAIL DATED : 1. Revised relay settings for Dichpally-Ramagundam line is given as per the Lr.No.CE/PS/SE/PS/SP-1/111/Relays 400kV Dichpally/Vol- 2/D.No. 11/18, Dt: As per the Ramakrishna Committee guidelines and same will be adopted in field in coordination with NTPC/PGCIL and based on Line Clearance availability. 2. Instructions for revising Zone-2 settings for 220kV and 400kV lines will be issued to the concerned field officials shortly. --- NTPC Ramagundam MAIL DATED : Zone -2 timing implemented at NTPC end is 0.4 Sec. Same has been communicated to TSTRANSCO on 30/01/2018. Page 7 of 34

18 66/ II/ 8 Tripping of 400 kv Khammam KTPS lines at 18:32 Lines 1 & 2 tripped on B-phase to earth faults 1 & 2 1. TSGENCO to keep uniform A/R dead-time of 1 sec on the lines emanating from TSGENCO/ their KPTS station. PGCIL (SR-I) 2. PGCIL (SR-I) to enable Trip-on-Reclose (TOR) functionality for Zone-2 faults for Khammam KTPS lines at Khammam end, if such a feature is available in the concerned relay, and to configure it for sending Direct Trip (DT) Command to KTPS end. 3. PGCIL (SR-I) to set right time-sync issues w.r.t. Khammam end Event Loggers on Khammam KTPS lines. 4. For 400 kv Khammam KTPS line-1, PGCIL (SR-I), in coordination with TSGENCO, shall carry out the following: (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 with TSGENCO PGCIL (SR-I) Mail dated : 2). TOR feature in MiCOM P444 relay enabled for 400kV KMM-KTPS lines at Khammam end. DT send on TOR trip is not as per protection philosopy. However if SRPC/SRLDC gives separate instructions exclusively for this line, the same shall be imoplemented after getting our CC approval ). At Khammam SS all DR & ELs are time synched. --- Completed. 4). --- TSGENCO Mail dated : 1). If the auto reclose function dead time kept same at both ends as 1 sec uniformly. In case of persistent fault, it leads to feed the fault from both ends and cause the generator breaker switching on to high fault current and chances of pole slip. To avoid this time differentiated A/R scheme to be implemented. In KTPS 400KV Line I & II at KTPS end dead time is 1.2sec and at KMM end it is 1sec. In our relay 7SA522 does not have the adaptive dead time function A/R. Hence, it is requested to send DT in case of on 3-phase trip and A/R unsuccessful at KMM end to avoid reclose attempt from KTPS end after dead time (1.2Sec) for persistent faults. [with PGCIL (SR-I)] We communicated to M/s Siemens to upgrade the firmware version regarding adaptive dead time. Hence, it is requested to review these settings to reduce the stress on Generating Station --- Completed 2. It was made clear to PGCIL (SR-I) that this is a specific case of those 400 kv lines where one one of the ends is a generating station, and the other end is grid-connected substation having TOR feature in line protection relays. The said recommendation of enabling TOR along with sending DT to the other end is basically to ensure safety of Generating Units at the other end. Accordingly, PGCIL (SR-I) was asked to take steps to ensure the same PGCIL (SR-I) informed that shutdown was availed by TSGENCO on , and all issues relating to PLCC including end-to-end testing were carried out. --- Completed Page 8 of 34

19 66/ II/ 10 Tripping of 400/ 220 kv ICT s 3 & 4 at Ramagundam STPS at 19:46 Triggering incident was failure of 220 kv 1. NTPC to disable high-set of DEFR on the 220 kv lines emanating from their B-phase LA in ICT-3 LV extension feeder (220KV line-2) at Ramagundam STPS. Malayalapalli substation 2. NTPC/ TSTRANSCO to provide Line Differential Protection (with or without pilot) on 220 kv Ramagundam Malayalapalli lines 1 & 2 & 3. NTPC- Ramagundam/ TSTRANSCO NTPC mail dated : 1. High set DEFR on 220 KV lines is disabled ----Completed TSTRANSCO informed that the works are under progress, and are targeted to be completed in 3 months time. TSTRANSCO MAIL DATED : Line Differential Protection will be provided within 3 months i.e., by end of March, /I/2 Complete outage of 220 kv Kadra Power Station of KPCL at 11:41 Triggering incident was tripping of 220 kv Kadra-Kodasalli and 220 kv Kadra-Kaiga line. There was no generation at Kadra in antecedent condition. 1. KPCL to investigate the reasons for non-tripping of 220 kv Kadra Kodasalli line from Kadra end by any of the Main protection relays, and opening of only B- ph pole at Kodasalli end, and furnish an action taken report on the same. 2.KPCL to sort out issues relating to downloading of DR s & EL s at Kadra PH at the earliest. KPCL/ NPCIL (KGS) Status received vide NPCIL mail dated : 4. The event logger(escada) has inherent time resolution of 10 millisecond for digital inputs. In future higesht resultion event logger history will be extratced for submission to grid authorities..--npcil-kaiga ----Completed 3. KPCL to use both the 220 kv buses as main buses under normal operation, and to go for single bus operation only during emergencies at their Kadra PH. 4. NPCIL (KGS) to configure time resolution of Event Loggers to milli seconds at their Kaiga GS. 1). Kadra-kaiga 220KV line tripped on both end in Zone-1 distance protection. Fault distance is 0.9KM from kadra end. Kodasalli-Kadra 220KV tripped at Kodasalli end only in Zone-1 fault. Reason for tripping is the both Kadra-kodasalli, kadra-kaiga line are in same tower, hence same fault reflected adjuscent line. Because of no Bus source, Kadra end relay stopped to detect, hence Kadra end breaker was intact Completed 2). Issue relating to downloading of DRs & Els at Kadra PH rectified. --- Completed 3). KPCL informed that they have planned to take up providing double-bus operation at their 220 kv Kadra PH, 220 kv Gersoppa PH, and 220 kv Raichur TPS through PSDF funding, and DPR for the same is under preparation. After obtaining approval of the same from their management, other activities inluding tenders floating, approaching PSDF would be taken up. All these activites are targeted to be completed within 2 years. --- Page 9 of 34

20 69/I/2 Complete outage of 400kV TPCIL station at 21:37 400kV TPCIL - Nellore line-1 got tripped at TPCIL end during failure of LA of Station Transformer-2 at TPCIL. Running Units at TPCIL got tripped due to loss of evacuating line. 400kV TPCIL - Nellore PS line-2 was under emergency shutdown 1. TPCIL to configure DEF protection such that it remains in blocked condition as long as Distance Protection is active, and becomes active only when distance protection does not pickup. 2.PGCIL (SR-I) to ensure healthiness of Carrier communication, and the set PUP mode of carrier aided scheme operates reliably on TPCIL lines 1 & 2. TPCIL/ PGCIL (SR-I) PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL to complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit written confirmation to PGCIL (SR-I) by PGCIL (SR-I) assured that with receipt of above confirmation from TPCIL by Dec, 2017, they would be able to complete the work by February, APTRANSCO informed that they would be able to implement LDP from their & APGENCO side by April, In this regard, PCSC forum made it clear that the recommendation is about providing LDP as both Main-I & Main-II relays on all stated lines in Nellore Complex, ans asked all stakeholders to ensure & comply with the same. 69/II/10 Tripping of 400 kv Hassan-UPCL line-1& at 16:11 R-Y phase to earth fault in line-1 and R-phase to earth For the line trippings under consideration, PGCIL (SR-II) and UPCL to furnish fault had occurred simultaneously in Line-1 & line-2 relevant COMTRADE (.cfg &.dat) files to PCSC forum so that the same could be respectively. Line-1 got tripped due to LLG fault. In Line-2, analysed using PSCT software by PRDC for correct operation of the relays auto-reclose was successful at Hassan and 3-phase trip at involved. UPCL. PGCIL (SR-II)/ UPCL Yet to be informed 69/III/3 Tripping of 400 kv Kurnool(PG) Kurnool(AP) line at 02:03 Line tripped on B-ph to ground fault. A/R was 1) PGCIL (SR-I) and APTRANSCO to provide for Line Differential Protection as both unsuccessful at both Kurnool (AP) and Kurnool (PG) ends. the Main protections on 400 kv Kurnool (AP) Kurnool (PG) lines 1 & 2 lines. APTRANSCO/ PGCIL (SR-I) APTRANSCO maild ated : A/R scheme on 400kV Kurnool (PGCIL) feeder-2 will be checked after getting LC. 2) APTRANSCO to furnish an action taken report w.r.t. resolving A/R nonoperation at Kurnool-AP end for the subject trippings and configure EL for capturing PDR operation at their 400 kv Kurnool-AP SS. 69/III/7 Tripping of 220 kv Ragulapadu Alipura line at 01:30 Line tripped on B-Ph to earth fault. A/R was successful at KPTCL and APTRANSCO to sort out issues relating to incongruence in denoting R, APTRANSCO/ Regulapadu and breakers at Alipura end got tripped. Y, B phases of the electric supply on their respective sides. KPTCL APTRANSCO maild ated : APTRANSCO would extend support and requirements if any,for the rectification proposed by KPTCL. It was noted that the original Gooty - Lingapur line got LILOed at BTPS, Alipura, and Ragulapadu. It was also noted that Phase Discrepancy is being observed in Ragulapadu - Alipira section only. When enquired about the same, KPTCL informed that they would examine the issue in detail, and would inform the action lan proposed by next PCSC-71 meeting. On this, APTRANSCO was also asked to render all help required from their side to KPTCL. APTRANSCO maild ated : APTransco world extend required support. 71/III/2 Tripping of 400 kv Suryapet-VTPS line at 14:39 Line tripped on Y-phase to earth fault. Zone-2 operated at VTPS due to non-receipt of carrier 1. APGENCO and TSTRANSCO to put A/R into service from their respective ends on 400 VTPS Suryapet line. 2. For the line under consideration, the following shall be carried out by APGENCO, in coordination with TSTRANSCO: (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. APGENCO/ TSTRANSCO Yet to be informed Andhra Pradesh 52/I/2 (GD) Complete outage of 220 kv Yerraguntla substation and tripping of running Units at Rayalaseema TPS at 10:39 HV B-Ph Current transformer of 100MVA Power 1. APGENCO to check associated logic for lube oil pump for correct operation Transformer -1 failed resulting into a bus fault on 220KV under transient low voltage conditions at Rayalaseema TPS, Unit-1. Bus-1. Unit-1 and Unit-5 at RYTPS tripped during the fault at Yerraguntla substation 2. 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 It was noted that no APGENCO representative had come to attend the meeting. Page 10 of 34

21 57/II/9 Tripping of 400 kv Nellore (PG) - NPS line- 1, 400 kv Krishnapatnam-Nellore (AP) lines -1&2 and 400kV NPS - MEPL line at 19:05 Triggering incident was snapping of Y phase conductor in APGENCO to furnish a report on the remedial action implemented w.r.t. APGENCO 400kV Nellore (PG) - NPS line-1. Distance relay at overreaching of Krishnapatnam end distance relays during the tripping of 400 kv It was noted that no APGENCO representative had come to attend the meeting. Krishnapatnam end over-reached in Zone-1, and resulted Nellore (PG) - NPS line-1 in tripping of 400kV Krishnapatnam Nellore (AP) lines - 1&2 from Krishnapatnam end. Distance relay at MEPL APGENCO Mail dated : Procurement of relays is under progress over-reached and resulted in tripping of MEPL-NPS line from MEPL end. 69/II/1 Multiple trippings at Tripping at 220 kv Srisailam Right Bank power station at 14:39 220kV Srisailam RB Markapuram S/C line and 220 kv Srisailam Podili S/C line tripped on operation of distance protection. Srisailam Units - 3, 4, 6 and 7 got tripped during the incident. 1.APGENCO to furnish compliance report on the recommendations given by PSAG-9 team that had visited Srisailam RB PH on October, APGENCO to carry out the following: (i)removal of DC earth leakage in station switchyard on priority basis (latest by ) (ii)integration of Station earth-mat and Switchyard earth-mat. APGENCO Yet to be informed 68/III/9 Tripping of 400 kv Kalpaka Asupaka line at 10:48 Y-phase to earth fault. Auto reclose was stated to be successful at Kalpaka end. At Asupaka end Auto-reclose had not operated due to problem in configuration settings. For the subject line relay at Kalpaka end, APTRANSCO to configure DR for a posttriggering period of 2 sec and EL for all required protection (analog & digital) events APTRANSCO APTRANSCO Mail dated : Post triggering period of 2 see for DR is configured. Wiring under the scope of retrofitting works is being carryout by EMC. EL will be configured on completion to wiring works. APTRANSCO informed that the recommedned works would be completed by APTRANSCO maild ated : Informed to EMC to complete retrofitting work on top priority 69/II/7 Tripping of 400 kv Uravakonda Jamalamadugu line at 10:22 Line tripped on overvoltage at Uravakonda end and Direct Trip received at Jamalamadugu end. DR & EL of Uravakonda end not furnished. APTRANSCO to complete configuration of DR s & EL s for all protections relays at APTRANSCO APTRANSCO Mail dated & their 400 kv Uravakonda SS, and render them suitable for Instructions were issued for taking necessary action. extraction/downloading of relevant tripping records/ events within a month s time. APTRANSCO maild ated : Configuration of DR & EL s in the relays completed configuration of DR & EL at SAS is to be verified. Page 11 of 34

22 61/III/5 Tripping of 400 kv Khammam - KTPS line at 10:52 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. Telangana 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 (from to ). TSGENCO TSGENCO mail dated : 1. According to SRPC phylosphy power swing block settings are changed to ALL ZONES BLOCK EXCEPT ZONE Completed 2. M/s. Siemens is requested to depute the service Engineer to update the firm ware of existing SIPROTEC relays in 400KV switch yard. This work will be completed on or before TSGENCO mail dated : Completed 2. As this KTPS line-ii is being LILOed at KTPS, Stage-VII, those relays would be replaced with line diff relays. --- As recommeded, TSGENCO was asked to migrate to new versions of firmware in consultation with relays OEM /II/2 Tripping of 400kV Kurnool-Srisailam line at 23: at 21:57 Line tripped on operation of Over-Voltage protection at Srisailam and Direct Trip was received at Kurnool. Considerable voltage difference was observed between R, Y & B phases. TSGENCO to adopt stipulated OVR, Stage-I gradings for the 400 kv lines emanating from their 400 kv Srisailam LB RH, and furnish an action taken report w.r.t. mitigating observed voltage difference among R & Y & B phases TSGENCO Yet to be informed at 20: at 21:19 70/II/3 Tripping of 400 kv Satenapalli-Srisailam line at 22: at 23:09 Line tripped on operation of over-voltage protection at Srisailam and Direct Trip was received at Sattenapalli. Considerable voltage difference was observed between R, Y & B phases at Srisailam end. TSGENCO to adopt stipulated OVR, Stage-I gradings for the 400 kv lines emanating from their 400 kv Srisailam LB RH, and furnish an action taken report w.r.t. mitigating observed voltage difference among R & Y & B phases. TSGENCO Yet to be informed at 18:46 71/II/7 Tripping of 400 kv Narnoor Srisailam LB line at 18:49 Line tripped due to operation of over voltage protection at Srisailam LB end. Considerable phase difference was observed between phases at Srisailam end 1. TSGENCO to take steps to replace the existing faulty CVT s at Srisalam end on 400 kv Srisailam Narnoor line at the earliest. 2. TSGENCO to adopt stipulated OVR, Stage-I gradings on all 400 kv transmission lines emanating from Srisaliam LB. TSGENCO Yet to be informed at 19:10 67/III/1 Tripping of 400 kv Gajwel - Bhoopalapalli line at 13:13 Line tripped on B-ph to earth fault. Auto-reclose was successful at Bhoopalapally end and breaker tripped at Gajwel. 1. For the line under consideration, TSTRANSCO to sort-out A/R related issues at Gajwel end. 2. For the line under consideration, TSTRANSCO to configure EL at Gajwel such that PDR operation is also captured in it. 3. TSTRANSCO to configure DR s of protection relays at their Gajwel SS for a posttriggering period of 2 sec so as to capture complete A/R operation. TSTRANSCO 1) & 2) & 3) TSTRANSCO informed that given reocmmendations would be complied with by TSTRANSCO MAIL DATED ON : Line Clearance could not be availed on as company engineer could not come as per Schedule. It is proposed to carry out End to end testing on by availing Line clearance. 69/III/1 Tripping of 400 kv Gajwel - Narsarpur line at 03:55 Tripped on B-phase to earth fault. Auto-reclose attempt could not be validated with submitted DR of both ends and from PMU data plot. TSTRANSCO to configure DR s and EL s of Protection relays at their 400 kv Gajwel TSTRANSCO TSTRANSCO MAIL DATED ON : SS and 400 kv Narsapur SS for proper time-scales and for recording all required Line Clearance could not be availed on as company engineer could not come as per Schedule. It is proposed to check Auto protection events. reclosure function testing on by availing Line clearance. Page 12 of 34

23 PAR/ PCSC-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/ TSTRANSCO 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. TSGENCO mail dated Procurement of Differential Protection relays is under process and the work will be completed by the end of November TSGENCO mail dated Procurement of Line Differential Protection Relays is under process and the work will be completed by the end of January TSGENCO informed that they are in constant touch with TSTRANSCO in this regard, and hope to implement LDP by February, TSTRANSCO informed that procurement of LDP relays is under progress, and assured that LDP would be implemented in 3-months time. TSTRANSCO MAIL DATED ON : The matter is being coordinated with TSGENCO. 62/IV/5 Tripping of 400 kv Gajwel-Bhoopalapalli line at 15:00 Line tripped at Bhoopalapally on DT receive and was holding from Gajwel. For the line under consideration, TSTRANSCO to carry out the following in TSGENCO / coordination with TSGENCO: TSTRANSCO (i) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. (ii) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. (iii) Frequency bandwidth tuning of PLCC link for faithful transmission of signals shall be carried out. TSTRANSCO mail dated on : 1. Letter is been given to field for conducting end to end testing of 400kV Gajwel-Bhoopalpalli-1 line --- TSGENCO mail dated & : TSGENCO/KTPP will make all the necessary arrangements for checking the end to end protection through communication system prior to intimation by TSTRANSCO --- TSTRANSCO informed that PLCC end-to-end testing would be carried out as recommended by TSTRANSCO MAIL DATED ON : Line Clearance could not be availed on as company engineer could not come as per Schedule. It is proposed to carry out End to end testing on by availing Line clearance. Page 13 of 34

24 Karnataka 41/I/1 GD-1 at 220kV Kadra power Station of KPCL at 12:56 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. 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 : Completed Completed. 3. Possibility of DC-1 & DC-2 arrangement and splitting of DC will be reviewed --- Status received vide KPCL mail dated : 3. Providing 2 separate DC sources is under process --- Status received vide KPCL mail dated : 3. Work under implementation stage KPCL informed that for providing 2 separate DC sources with new battery charger, LOA & Work order were placed on M/s Eltek Power system. The works would be completed in March, /II/21 Trippings at 220kV Raichur TPS at 01:35 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. Status received vide mail dated : 1) --- Completed. 2) --- Completed. 3) Two Bus operation for 220kV bus is being carried out whenever required. However scheme for tripping of one bus during LBB/fault and maintaining the other bus intact by tripping B/C breaker will be taken up in R&M works. --- Status received vide KPCL mail dated : 3) DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is placed for funds from PSDF. After the approval of the DPR, the work is proposed to be taken up. 3) KPCL informed that DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is placed for funds from PSDF. After the approval of the DPR, the work is proposed to be taken up. Time frame requested for is 2 yrs. Page 14 of 34

25 54/II/4 Tripping of 400 kv Raichur TPS- Mahboobnagar line at 10:23 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 KPCL Status received vide KPCL mail dated : impedance protection relay under observation, and replace it with a spare at the The electro-mechanical back-up impedance protection relay is in service. However, Budgetary offer obtained for the retrofitting of earliest. Line reactor protection with Numerical relay and is under process Status received vide KPCL mail dated : Tendering under process KPCL informed that the new numerical relay for backup impedance protection of Line Reactor would be provided by June, KPCL Mail dated : E-tender for the retrofitting work of Line Reactor protections will be invited shortly. 54/II/9 Tripping of 400kV Raichur TPS Bus at 21:12 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. 2.KPCL to take steps to provide dedicated breaker flashover protection to all breakers at Raichur TPS at the earliest. KPCL Status received vide KPCL mail dated : 1. (ii) Hot line water washing stopped and off line water washing is carried out whenever the 400 KV Unit or line is under tripped condition / Shutdown condition. --- Completed 1. (iii) Silicon coating for Unit#8 main & tie breakers carried out in Sep'16 and same is under observation. Till today in order and good condition. For remaining breakers, since it is big order, approval for the same is under process Static / Electromechanical relays are existing in all 1 to 7 units. Breaker flash over protection feature will be enabled (if available) in the numerical relays which will be retrofitted in phased manner during R&M works. Status received vide KPCL mail dated : 1.(i) (ii) Hot line water washing stopped and off line water washing is carried out whenever the 400 KV Unit or line is under tripped condition / Shutdown condition. --- Completed 1. (iii) Silicon coating for Unit#8 main & tie breakers carried out in Sep'16 and same is under observation. Till today in order and good condition. For remaining breakers, since it is big order, approval for the same is under process Static / Electromechanical relays are existing in all 1 to 7 units. Breaker flash over protection feature will be enabled (if available) in the numerical relays which will be retrofitted in phased manner during R&M works (iii) As upgradation of 400kV switchyard equip's to be taken under PSDF funds, Silicon rubber coating for breakers is deffered till then Replacement by Num relay for Units - 5,6 & 7 completed in the month of Oct Main-I is Seimens make and Main-II is ABB make. --- KPCL mail dated : 2. Replacement of Numerical relays for Units-5, 6 & 7 have been completed. Referred to OEM for providing the Breaker flashover protection for all the breakers. 54/II/13 Tripping of Units at 220 kv Raichur TPS at 15:36 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 bus-coupler at 220 kv KPCL Status received vide KPCL mail dated & : RTPS, KPCL is recommended to put in service the double-bus operation at 220 kv Two Bus operation for 220kV bus is being carried out whenever required. However scheme for tripping of one bus during LBB/fault RTPS by suitably distributing loads within 15 days. and maintaining the other bus intact by tripping B/C breaker will be taken up in R&M works. 3) KPCL informed that DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is placed for funds from PSDF. After the approval of the DPR, the work is proposed to be taken up. Time frame requested is 2 yrs. 58/I/3 (GD) Complete outage of 220 kv Kadra power station of KPCL at 14:40 LBB of 220kV Kodasalli breaker at Kadra end got 1) KPCL to check settings of LBB protection in all relays from which it was operated which resulted in tripping of Bus at Kadra and in implemented, and ensure that their configuration, logic, and timing are in order turn led to tripping of all elements at their 220 kv Kadra PH. 2) 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. 3) KPCL to ensure time-sync of all relays (DR s & EL s) with GPS at their 220 kv Kadra PH. 4) KPCL to provide stand-alone Event Logger at their 220 kv Nagjheri PH. KPCL Status received vide KPCL mail dated : 1. All logics checked and found normal. LBB timing checked and found 200msec as per KPTCL MRT recommendation. - Completed 2. Work Under Progress New GPS System commissioned along with new numerical and synchronised with GPS system - Complied 4. Work Under Progress ---- Status received vide mail dated : 1),3),4) Completed 2. Auto Start of DG set is taken up KPCL informed that for AMF of DG, Scheme prepared & material procurement under process. The AMF scheme will be implemented in January The GPS system commissioned on Nov 2016 & all the numarical relay time synchronised with GPS ---- Completed Page 15 of 34

26 62/I/1 Complete outage of 220 kv Nagjheri substation of KPCL at 00:38 Triggering event was the fault on 220 kv Nagjheri Kodasalli line-2. Both buses of 220 kv Nagjeri power station of KPCL got de-energized. 1. KPCL to adopt the following VT fuse-fail logic for all 220 kv lines emanating from NPH: Under VT fuse fail condition, distance protection shall normally be kept blocked. However, upon detection of a fault (sensed by negative sequence component), blocking of distance protection shall give rise to operation of its inherent Over- Current protection set with a definite time delay of 500 msec. 2. KPTCL/ KPCL to revise Zone-2, Zone-3 and Zone-4 (reverse) timings of DPR of all 220 kv lines emanating from Nagjheri PH in line with Ramakrishna Committee guidelines. KPCL Status received vide mail dated : 1. Already settings are discussed with EE(RT), Hubli and soon relays will be tested for VT fuse fail condition. 2. Timings of Zones were set as per the recommendations of CE(RT) & R&D, KPTCL, Bangalore & EE(RT), KPTCL, Hubli.Regarding revision of timings will be carried out in co- ordination with EE(RT), KPTCL, Hubli. Status received vide mail dated : 1. As per the recommendations of SRPC and SRLDC, in the event of VT fuse fail, non directional over current and earth fault feature is enabled in the distance relay with a definite time lag of 600msec on pick up and the same is tested by KPTCL Hubli(RT) and KPCL jointly on Completed KPCL informed that Zone settings of distance relays of all 220 kv lines emanating from Magjheri SS had been revised in line with Ramakrishna Committee guidelines Completed. 69/II/8 Tripping of 220 kv Kaiga- Kadra line at 22:22 While de-synchronising of Unit-2, B-phase pole of GCB did not open and pole descrepancy relay operated. Hence all 220KV lines CB hand tripped. KPCL to take steps to replace the existing static protection relays for Generator Units and Generating Transformers (GT s) with suitable Numerical relays at their 220 kv Kadra PH. KPCL Yet to be informed 40/I/1 GD-1 at 220kV Ambewadi Station of KPTCL at 21:22 Triggering incident was B-phase to earth fault in 220kV Ambewadi- Nagzari line-1. B-pole of breaker did not open at Ambewadi end. LBB protection not available at Ambewadi end. All elements tripped on Zone-2 from remote ends. 1. Till the completion of R&M works for bus bar and LBB protection, KPTCL shall explore the possibility of having split bus operation at Ambewadi and submit the details of the same to PCSC forum. 2. KPTCL shall provide the details of the tripping of Supa hydro station connected downstream from 110 kv bus. KPTCL Mail received on : 1. In view of operating 220kV Ambewadi SS in split bus mode, action is being taken up by KPTCL. 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 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 KPTCL 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. KPTCL mail recieved on : 1. Bus-II PTs yet to be commissioned.planned to complete before end of April KPTCL mail recieved on & : 1. Yet to be attended --- KPTCL Mail dated & 1. Recommended works at Ambewadi have not been taken up due to various problems faced due to poor response from the turn key agency M/s ERL. A site meeting is planned during this month to discuss about further plan of action for attending SRPC recommendations pertaining to the Sub station. The issue was discussed in the review meeting. Considering the importance of the substation and delay in executing the works, it was decided to escalate all pending issues relating to Ambewadi SS to KPTCL top Management for early completion. Page 16 of 34

27 40/IV/1 220kV Sedam- Tandur line at 22:20 Line tripped on Yphase to earth fault from both the ends KPTCL was requested to explore the possibility of providing A/R feature to this line and submit the remedial measures to the PCSC forum. KPTCL 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. KPTCL 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. KPTCL mail recieved on : SEE,SCADA to update the latest status KPTCL mail recieved on : Action is being taken to restore carrier protection.ar will be enabled once carrier signal is restored. KPTCL Mail Recieved dated : The Wave traps required are supplied under R&U project and the same is to be commisioned at Sedam end for restoration of PLCC. Also,M-II distance relays have already been supplied by GE Ltd. KPTCL Mail dated : Carrier protection is to be restored. B/U OC and EF relay is to be replaced by M-II distance relay. Required materials like wave trap, M-II distance relay are already supplied. The work will be taken up on top priority through GE Ltd. KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into service by February, /I/4 Complete outage at 220kV Sedam Substation of KPTCL (GD-1) at 8.00 R-Phase to ground fault occurred on 220kV Sedam- Shahpur line. Fault not cleared from Sedam end due to stuck-breaker 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. KPTCL to provide Bus bar and LBB protections for 220 kv bus at Sedam S/s. 2. KPTCL to implement A/R feature on 220 kv Sedam-Tandur inter-state line. KPTCL 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. KPTCL 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. KPTCL Mail recieved dated : 1 & 2). Bus Bar Protection panel and required Wave traps are supplied under R&U. Wave trap to be commisioned in Tandoor line and PLCC to be restored.once PLCC is restored AR will be enabled. The Wave traps required are supplied under R&U project and the same is to be commisioned at Sedam end for restoration of PLCC. KPTCL Mail dated : 1 & 2) Replacement of Bus Bar Protection is included under R&U project. Awarded to M/s GE Ltd. Panels have alredy been supplied by the Agency. The work will be taken up on top priority. KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into service by February, Page 17 of 34

28 42/I/1 Complete outage of 220kV Sedam substation of KPTCL at 14:24 Fault occurred in 220kV Sedam-Shahpur line 1. KPTCL to provide Bus Bar protection and LBB protection at Sedam S/s and furnish the status of their implementation to PCSC forum. 2. KPTCL to implement A/R feature on 220 kv Sedam-Tandur inter-state line. KPTCL 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. KPTCL Mail Recieved dated : Bus Bar Protection panel and required Wave traps are supplied under R&U. Wave trap to be commisioned in Tandoor line and PLCC to be restored.once PLCC is restored AR will be enabled. KPTCL Mail dated : 1. Replacement of Bus Bar Protection is included under R&U project. Awarded to M/s GE Ltd. Panels have alredy been supplied by the Agency. The work will be taken up on top priority. 2. AR feature will be enabled during retrofitting of Main-2 relays. 1 & 2) KPTCL informed that the works are under progress and are targeted to be completed by February, /I/2 (GD) Complete outage of 220 kv Ambewadi substation of KPTCL at 7:51 Fault in 220kV Ambewadi-Nagjheri line-2 1. KPTCL 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, KPTCL shall explore the possibility of having split bus operation at Ambewadi and submit the details of the same to PCSC forum. KPTCL 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. KPTCL Mail Recieved dated & : 1.Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial lines, it was decided that enabling AR is not required. To clear the faults in the abovelines early, the timings of the Zone 2 was reduced to 150mS and the Back Up EFR timings have been reducedto 150mS. --- Completed 2.The planned works as per R&M could not be taken up due to the problem with the vendor and could not be taken up under R&U project due to administrative reasons The issue was discussed. Considering the importance of the substation and delay in executing the works, it was decided to escalate all pending issues relating to Ambewadi SS to KPTCL top Management for early completion. 48/I/2 Complete outage of 220kV Peenya Substation in Karnataka at 4:23:17 All connected 220kV lines and transformers were taken KPTCL to revise distance relay settings at Nelamangala end for 220 kv on 220kV North bus as South bus was under shut down Nelamangala Hebbal - Peenya line 1 for the effective line length of 17 km. for conversion of strung bus to rigid bus and isolator These new settings can be appropriately reviewed as and when the tiearrangement at Hebbal is done away with. replacement under R&M works. Failure of HV side Y 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. KPTCL KPTCL 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. KPTCL Mail Recieved dated : Since usage of this line as an Incoming line at Peenya is required for emrgency purposes, the settings of this line at Nelamangala end will be reduced to 17KMs and as a special case, to cover the rest of the length of the line, Zone 2 timing will be reduced to 150 ms. KPTCL Mail dated : The revised settings to be adpopted for this line considering reduced protected line length( 17KMs) is issued as a special case which will be implemened and tested during scheduled outage. KPTCL informed that the revised setting would be implemented by December, Page 18 of 34

29 48/I/3 Outage of 220kV Ambewadi station in Karnataka at 10:41 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. KPTCL to fast-track providing A/R on all 220 kv lines emanating from Ambewadi SS to prevent Station shut-down on temporary faults. KPTCL KPTCL mail received on : Will be complied in a months time. KPTCL Mail Recieved dated : Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial lines, it was decided that enabling AR is not required. To clear the faults in the abovelines early, the timings of the Zone 2 was reduced to 150mS and the Back Up EFR timings have been reducedto 150mS. KPTCL Mail dated : Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial lines, it was decided that enabling AR is not required. To clear the faults in the abovelines early, the timings of the Zone 2 was reduced to 150mS and the Back Up EFR timings have been reduced to 150mS. In view of the above, it is requested to drop the issue from this list. KPTCL informed that AR would be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of Back Up protection by Distance protection relay at Ambewadi. Considering the importance of the substation and delay in executing various works, it was decided to escalate all pending issues relating to Ambewadi SS to KPTCL top Management for early completion. 51/II/21 Multiple tripping at 400kV Guttur SS at 18:53 Failure of Lightning Arrestor of Y-phase Line Reactor of 1. KPTCL to configure all DR s and EL s at 400 kv Guttur SS so that they will also 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. get triggered for BBP operation. 2. KPTCL to ensure time-synchronization of all DR s and EL s with GPS at their 400 kv Guttur SS. KPTCL KPTCL Mail received dated : SEE, RTC, Bangalore to update the status KPTCL 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. KPTCL Mail received dated : GPS and accessories will be supplied during May 2017, expected to complete the work within a month after supply of materials. KPTCL Mail Recieved dated : As discussed during the earlier PCSC meetings, current limit of 12.5KA has been added in the logic of AR at Guttur end to prevent reclosing during failure of LA or any other very close faults. Replacement of existing static BBP by new numerical BBP with Main 1&2 will be taken up at Guttur for which the panels are already supplied. Presently, replacement of 220KV side Bus bar protection is under progress. DI for delivery of GPS receiver has already been issued, but there is a delay in dispatch of the same by M/s GE Ltd due to GST issues, which is also addressed recently. KPTCL Mail dated : 1). The work of replacing static type 400kV Bus Bar Protection scheme by numerical BBP is under progress at Guttur ). GPS time syncronising device is expected to be supplied before end of December ) & 2) KPTCL informed that the works are under progress, and are targeted to br completed by February, Page 19 of 34

30 52/I/3 Complete outage of 220 kv Shimoga substation at 15:03 220kV Bus Bar protection operated during failure of R phase CT in DVG-2 line bay. KPTCL to operate 220 kv Shimoga on multi-bus operation under normal conditions, and put it on single-bus operation only under emergency conditions. KPTCL KPTCL Mail received dated : Replacement of existing BBP by new BBP with 4 zone protection is being taken up under R&U. KPTCL Mail Recieved dated : GE Ltd has already supplied the necessary Bus Bar protection panels for replacement of the existing static type BBP by new numerical BBP with 4 zone protection under R&U project. The work of commissioning the same will be taken up shortly. KPTCL Mail dated : Due to operational constraints two/ multi bus operation is not being implemented. It was noted that Shimoga SS is having required configuration for providing double-bus operation. However, due to large no. of feeders (15 in no) with variable gneration at certain remote ends like Varahi, the flows on these lines are bound to vary. As such it is necessary to zero in on appropriate arrangement of feeders on different buses so that bus-isolators of the feeders are not overloaded. The issue was discussed. KPTCL was asked to try out multi-bus operation on trial basis to arrive at suitable arrangement of feeders. 53/I/1 Complete outage of 220kV Peenya Substation of KPTCL at 11:39 220kV Peenya-Nelamangala-3 tripped on B-E fault at KPTCL to furnish a report on the tripping of 220 kv Peenya-Nelamangala line-4 Hrs both ends. At the same time, 220kV Peenya-Nelamangala- Nelamangala detailing the remedial measures taken including the settings 4 tripped on R-Y fault only at Nelamangala end, and was adopted for Z1B (Zone extension) and Power Swing Block. in service from Peenya end. Due to tripping of these two lines, 220kV Peenya-Nelamangala-2 tripped on overcurrent protection. KPTCL KPTCL Mail received dated : SEE, RTC, Bangalore to update the status KPTCL Mail Recieved dated : Since usage of this line as an Incoming line at Peenya is required for emrgency purposes, the settings of this line at Nelamangala end will be reduced to 17KMs and as a special case, to cover the rest of the length of the line, Zone 2 timing will be reduced to 150 ms. KPTCL Mail dated : Considering it as special case, revised settings to be adpopted for this line considering reduced protected line length( 17KMs) is issued which will be implemened and tested during next scheduled outage. KPTCL informed that the revised settings would be implemented by December, /II/1 Tripping of 220 kv Chikkodi-Mudshingi and 220 kv Chikkodi-Talandage lines at 03:03 Triggering incident was failure of B-ph PT of 220kV Bus-2 (western bus) at 220KV Chikkodi substation. 220KV Chikodi- Belgaum-I line tripped on DEFR (Inst), 220KV Chikkodi-Kudachi line tripped on Distance protection and also 100MVA transformer-2 tripped on E/F protection. 1.KPTCL to take steps to provide busbar protection at their 220 kv Chikkodi interregional substation, and furnish a time-line for the same. 2.KPTCL to review distance protection settings for 220 kv Chikkodi Kudachi line. 3.KPTCL to furnish equipment failure report of the current incident to PSE&TD Division of CEA with a copy marked to SRPC. KPTCL KPTCL Mail Recieved dated : 1. The necessary Bus Bar protection panels are already supplied to Chikkodi under R&U project. Presently R&U works at sub stations subjected to audit are taken up. After completion of PAR works, the baove works are planned KPTCL mail dated : 1.The necessary Bus Bar protection panels are already supplied to Chikkodi under R&U project. Control cables have to be supplied. Presently R&U works at sub stations subjected to audit are taken up. After completion of PAR works at 26 Sub stations, remaining works will be taken up through M/s GE KPTCL informed that BBP would be provided by April, KPTCL informed that DPR settings had been reviewed Completed 3. EFR on failure of B-ph PT of 220 kv Bus-2 had been furnished to CEA Completed Page 20 of 34

31 62/II/3 Tripping of 220 kv Bus 2 and connected elements (220kV HAL #1 and 2, 400/220 kv ICT- 1, 2 and 220/66 kv ICT-2) at 400/220 kv Hoody substation of KPTCL (Load loss : 590 MW) at 23:06 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 busbar protection 1. KPTCL to provide Busbar protection at their 220 kv Hoody SS at the earliest. 2. KPTCL to furnish an Equipment Failure Report on CT failure to CEA with a copy marked to SRPC. KPTCL KPTCL mail received dated : Numerical BBP is being provided under R&M works. KPTCL Mail Recieved dated : 1. Numerical Bus Bar protection panels have already been supplied as a part of R&M works awarded to GE Ltd. Due to issue regarding the sectionaliser CTs, the work had stopped. Now the same is resolved and the the above work will be taken up after supply of sectionaliser CTs KPTCL Mail dated : 1. Numerical Bus Bar protection panels have already been supplied as a part of R&M works awarded to GE Ltd. Due to issue regarding the sectionaliser CTs, the work had stopped. Now the same is resolved and the the above work will be taken up after supply of sectionaliser CTs KPTCL informed that BBP at 220 kv Hoody would be provided by March, EFR on failure of R-ph CT of 220/ 66 kv Transformer-2 had been furnished to CEA Completed 62/II/5 Tripping of 220 kv 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-2 and 3) at 400/220kV Somanhalli substation of KPTCL (Load loss: 850 MW) at 14:34 Triggering incident was fault in 66 kv Somanahalli - Bannerghatta line and fault was cleared by operation of Back-up OCR at Somanahalli end. KPTCL to provide numerical Busbar Protection at their 220 kv Somanahalli SS at the earliest. KPTCL KPTCL mail received dated : Numerical BBP is being provided under R&M works KPTCL Mail Recieved dated : Tesing & Commissioning of numerical BBP at Somanahalli is under progress. There was some technical issue wth BBP scheme supplied to Somanahally which is being finalised in consultation with OEM SIFANG. Numerical BBP will be commissioned at Somanahally within a month's time. KPTCL Mail dated : Numerical Bus Bar protection Scheme will be commissioned at Somanahally before end of December /III/5 Tripping of 220 kv Sedam-Tandur line at 00:50 & at 17:27 Tripped on Y-Phase to ground fault due to distance protection operation. Auto reclosure could not be validated from the submitted DR/EL. KPTCL to enable and put A/R into service from Sedam end on 220 kv Sedam Tandur S/C line. KPTCL KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into service by February, Page 21 of 34

32 49/I/3 Complete outage of 220kV Ambewadi Substation of KPTCL at 14:34 220kV Nagjheri-Ambewadi line-1 tripped at 13:33 due 1. KPCL to provide A/R on all 220 kv lines emanating from Nagjheri PH. to B phase to earth fault. Ambewadi was radially fed from Nagjheri power station through 220kV Nagjheri- 2. KPTCL to provide A/R on all 220 kv lines emanating from Ambewadi SS. Ambewadi line-2. Tripping of this line caused 220kV Bus shut down at Ambewadi and remaining lines and transformers were hand tripped KPCL/ KPTCL KPTCL Mail Recieved dated : 1. coordination of KPCL has been requested for enabling AR lines terminated to Nagajari. 2. AR will be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of Back Up protection by Distance protection relay at Ambewadi. KPTCL Mail dadted & 1. KPTCL informed that Coordination of KPCL has been requested for enabling AR lines terminated to Nagajari KPTCL informed that AR would be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of Back Up protection by Distance protection relay at Ambewadi /I/3 Complete outage of 220 kv Nagjheri power station and 220 kv Ambewadi substation of KPTCL at 12:36 220kV lines from Nagjheri power house started tripping from 11:00 due to fault in lines. The sequence of tripping is shown in SOE list. At 12:33, 220kV Narendra-Ambewadi lines-1&2 got tripped which resulted in loss of evacuation path to Nagjheri station resulting in tripping of running Units and complete outage at Nagjhheri power station. 220kV Ambewadi station also got de-energized due to tripping of source feeders i.e. 220kV Narendra-Ambewadi-1&2 and 220kV Nagjheri-Ambewadi-1&2. 1. To avoid tripping of transmission lines on transient faults, KPCL/ KPTCL 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 Patrolling Protocol / Guidelines for Southern Region" on SRPC website). 2. KPCL/ KPTCL to review operation of SPS at NPH for functionality (reduction of generation with tripping of evacuating lines) and healthiness. 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. KPCL/ KPTCL Status informed during Special Meeting held on : 1. KPTCL 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 2. KPTCL 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 Completed KPTCL Mail received dated : 2. Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC for verification and approval Status received vide KPCL mail dated : 1. Will be reviewed in consultation with EE(RT), KPTCL, Hubli. 3. Both the lines are in charged condition. KPTCL Mail Recieved dated : 1) & 3) --- Completed 2). Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., Yet to be discussed and approved by the SRPC forum. --- KPTCL Mail dated : 1) & 3). --- Completed. 2). Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., yet to be discussed and approved by the SRPC forum The SPS proposed by KPTCL was discussed and the PCSC forum suggested certain changes for suitable incorporation. KPTCL agreed to look into the same and assured that the modified SPS would be furnished by January, Page 22 of 34

33 53/I/3 Complete outage of 220kV Ambewadi station of KPTCL and 220kV Nagjheri of KPCL at 14:40 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/ KPTCL to modify suitably the SPS at Nagjheri Power House such that it would also factor in the over loading of Ambewadi-Narendra lines. 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. KPCL/ KPTCL KPTCL Mail received dated : Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC for verification and approval Status received vide KPCL mail dated : 1. Tripped since there was evacuation problem and there were only two lines NA-1 and NA Completed 2. Will be reviewed in consultation with EE(RT), KPTCL, Hubli Both the lines are in charged condition. --- Completed. KPTCL Mail Recieved dated : 2. Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., yet to be discussed and approved by the SRPC forum. --- KPTCL Mail dated : 1) & 3). --- Completed. 2). Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., yet to be discussed and approved by the SRPC forum The SPS proposed by KPTCL was discussed and the PCSC forum suggested certain changes for suitable incorporation. KPTCL agreed to look into the same and assured that the modified SPS would be furnished by January, Tamil Nadu 62/II/7 Tripping of running Units & 230kV feeders at 22:36 at Tuticorin TPS of TANGEDCO (Gen Loss: 640 MW) Failure of Bus Section-I Y-ph CT resulted in operation of bus-bar protection for Bus Sections -I & II. Running Units#1, 4 and 5, 230 kv Kayathar, 230kV Kudankulam, 230kV Sterlite, Station Transformer-1, 2 & 3 got tripped during the incident. Unit 2 & 3 were not in service. 1. TANGEDCO to replace existing Check-Zone relay with a new one possessing required performance. 2. TANGEDCO to take steps to provide numerical busbar protection at their 220 kv Tuticorin TPS. TANGEDCO may also explore providing dual CT s (on either side) for all B/S breaakers at the time of commissioning of numerical BBP, if there were no space constraints. 3. TANGEDCO to take steps to provide for standalone Event Logger (EL) and standalone Disturbance Recorder (DR) with automatic downloading facility to a centralized server. TANGEDCO TANGEDCO mail dated : 1) New Relay is tested and ready for replacement.now all 5 units are in service.the relay will be replaced when lesser units are in service a)Steps are taken to renovate & mordernization of all the control panel into Numerical based control panels b) Since 230 KV indoor switchyard has no spare space providing dual CT`s is not fessible. -- Completed 3) Procurement of EL & DR is under progress. --- TANGEDCO mail dated : 1) Check zone New Relay is replaced on Completed TANGEDCO mail dated : 2).P & C wing gives clearance to TTPS to procure the Bus bar protection relays and protection relays and SER / DR system vide Lr.CE/P&C/SE/D/EEPC4/AEE3/F.TECH/D.27/17 Dated: To get administrative approval budgetary offer has bar protection relay from various companies ). SRPC vide Lr: SRPC/SE- III/CEA/2017/6450/DT: gives features of SER/DR. Budgetary offer will be called for SER / DR having above features. ---Penidng 2) & 3) The issue was discussed and TANGEDCO was asked to provide time-line for implementing the recommendations. Mail dated : Procurement work is under progress and will be completed by December /II/5 Tripping of 400kV Alamathy- SVChatram line-1&2 and 400/230kV ICT at S.V.Chatram at 15:29 Line-2 tripped on R-phase to earth fault. Line autoreclosed at SVChatram end 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 was requested to swap the relays between two stations, so that Main-1 and Main-2 will be of different make at each station. 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. Status received vide mails received on & & & & & : Different make Relays will be ensured for Main-I & II relays at Alamathy end. TANTRANSCO Mail received on & Different make Relays will be ensured for Main-I & II relays at Alamathy end. Page 23 of 34

34 TANTRANSCO Mail dated : Different make Relays will be ensured for Main-I & II relays at Alamathy end. Tender floated for relay procurement. TANTRANSCO informed that the recommendation would be complied with by June, TANTRANSCO Mail dated : Different make Relays will be ensured for Main-I & II relays at Alamathy end. Tender floated for relay procurement. Timeline: June Page 24 of 34

35 48/I/1 Disturbance in 220kV Tamilnadu system at 14:04 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 stub-towers along 230 kv OK Mandapam Myvady line to avoid excessive sag due to over-loading. TANTRANSCO 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. Status received vide mails received on & & & & & : 230kV Othakalmandapam - Myvadi feeder will be made LILO at Kongal Nagar. Line restringing will be carried out along with the above proposal. TANTRANSCO mail dated & : Othakalmandapam - Myvadi feeder will be made LILO at Kongal Nagar. Line restringing will be carried out along with the above proposal. Status received vid dated : Othakalmandapam - Myvadi feeder replacement of kundha conductor with Zebra and tower replacement work has been sanctioned. Work will be taken up. TANTRANSCO informed that 230 kv OK Mandapam - Myvady feeer was LILOed at Anaikadavu on Further replacement of the existing Kundah condductor with Zebra has also been taken up, and is targeted to be completed by June, /I/3 Complete outage of 230kV Mywadi at 6:28 station of TANTRANSCO Busbar protection got operated for a fault in 230kV Mywadi-Anaikadavu line TANTRANSCO to examine the feasibility of providing two main-zone operation TANTRANSCO for bus bar protection by exploring various alternatives like replacing existing buscoupler CB with a hybrid bus-coupler CB that comes with inbuilt CT, replacing existing BBP relay with another suitable relay that supports two main-zone operation, and implement the same. TANTRANSCO mail dated : 230kV Othakalmandapam - Myvadi feeder replacement of kundha conductor with Zebra and tower replacement work has been sanctioned. Work will be taken up. Timeline: June 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 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 Mail received on & : Provision of Bus Coupler bay arrangement was included in the Upgradation works proposed and the same was sanctioned by MoP through PSDF. Numerical relay allotted and being commissioned. Mail received on : Numerical BBP relay was commissioned on Status received vide mail dated & & : Numerical BBP relay was commissioned on Provision of Bus Coupler bay arrangement was included in the Upgradation works proposed and the same was sanctioned by MoP through PSDF. Status received vide mail dated : Numerical BBP relay was commissioned on Provision of CT in Bus Coupler bay is arranged and zone segregation will be provided. Status received vide mail dated & : Numerical BBP relay was commissioned on Provision of CT in Bus Coupler bay is arranged and zone segregation will be provided. Status received vid dated : Numerical BBP relay was commissioned on Provision of CT in Bus Coupler bay has been allotted. Zone segregation will be provided after commissioning of CT. TANTRANSCO informed that the recommendation would be complied with by March, TANTRANSCO Mail received on : Provision of CT in Bus Coupler bay is arranged and zone segregation will be provided. Timeline: March Page 25 of 34

36 51/I/1 (GD) Complete outage of 230kV Madurai S/s (Chekanaurani) of TANTRANSCO at 11:56 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. Status received vide mails recieved on and , , , , & & & & : 1 & 2) 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. Status received vide mail dated : 1 & 2) Contract awarded for providing third ICT & Bus modification works to accomodate bus coupler bay. Numerical BBP relay has been provided and tesing under progress. Status received vide mail dated : 1 & 2) Contract awarded for providing third ICT & Bus modification works to accomodate bus coupler bay. Numerical BBP relay has been provided and tesing under progress. Status received vide mail dated : 1 & 2) Contract awarded for providing third ICT & Bus modification works to accomodate bus coupler bay. Numerical BBP relay was commissioned onj Status received vid dated : 1 & 2) Numerical BBP relay was commissioned on Contract awarded for providing third ICT & Bus modification works to accomodate bus coupler bay ) --- 1&2) TANTRANSCO informed that multi-bus operation with Numerical BBP would be provided by June, 2018 for which the works are under progress ) TANTRANSCO informed that they would revert on providing Re-Trip feature fro LBB. --- TANTRANSCO mail received on : 1) Commissioning of Bus Coupler CT, Extended Bus with Additional Bus Coupler is under progress. Timeline: June ) Numerical BBP commissioned on to enable Bus seggregation. 3) Providing Re-Trip feature for LBB will be studied. 55/I/1 (GD) Complete outage of 230 kv Gummidipoondi Station of TANTRANSCO at 12:15 Flashover of Auto Transformer- 2 HV TANTRANSCO to take steps to provide double-bus operation at their 230 kv B-phase Isolator supporting insulator of 230kV Southern Gummidipoondi SS. Bus occurred at Gummidipoondi station. At the time of fault, Bus bar protection relay was not in service for precommissioning testing of Auto Transformer-2. All feeders got tripped due to operation of zone-2 protection from remote ends. TANTRANSCO Mail recieved on & : TANTRANSCO: Auto Transformer-2 HV side Bus isolator 'C'-phase support insulator of 230kV Southern Bus was replaced and Bus Bar Protection scheme was restored on Status received vide mails received on & & & & & & : CT is not available in the Bus Coupler bay for zone segregation. CT latch relay is to be provided for all bays for zone segregation. Status received vide mails received on & : Numerical Bus bar protection panel allotted and will be commissioned with zone segregation.. TANTRANSCO informed that Numerical BBP would be commissioned by March, TANTRANSCO mail received on : Commissioning of Numerical Bus bar protection is under progress. Zone segregation will be ensured. Timeline: March Page 26 of 34

37 58 Different type and Make of distance protection relays to be provided for Main-I & Main-II protection for 230kV feeders at 400 kv Sunguvarchathiram & 230 kv Sunguvarchathiram Substation [Carry-Over TANTRANSCO The issue was discussed in PCSC-58 meeting held on , when PCSC forum agreed to de-link the implementation of the Item from Protection Audit Recommendations] from the scope of Protection Audit Recommendations (PAR), and pursue it as part of PCSC Recommendations. Status received vide mails dated & & & & & & & : Different make Relays will be provided for Main-I & II relays at Sunguvarchatram end in a phased manner. TANTRANSCO informed that the recommended works of providing different make Relays for Main-I & Main-II are targeted to be completed by September, TANTRANSCO mail received on : Different make Relays will be provided for Main-I & II relays at Sunguvarchatram end in a phased manner. Timeline: September /II/17 Multiple tripping at 230 kv Alamathy Station at 11:13Hrs Bus Bar Protection (Zone-2) of 230 kv Bus-B got operated at Alamathy Station during fault in 230 kv Alamathy- Korattur feeder. 1. TANTRANSCO to check the healthiness of BBP relay by conducting stability test, and take appropriate remedial action like increasing voltage settings, ensuring the healthiness of CT s, using CT s with similar characteristics (equal saturation effects & equal winding resistances) etc. at their 230 kv Alamathy SS. 2. TANTRANSCO to replace the existing high-impedance BBP relay with its lowimpedance/ numerical variant so as to accommodate variation in CT characteristics at their 230 kv Alamathy SS. TANTRANSCO Mail received on & : 1. The Bus Bar Protection scheme will be tested for healthiness including the CT circuits. 2. High impedance BBP relay will be replaced by Numerical relay. Status received vide mails dated & & & : 1. The Bus Bar Protection scheme was tested for healthiness including the CT circuits. AREVA make CTs in Alamathy SS are having different kneepoint voltage for the cores. CT cores of higher knee point voltage has been choosen for BBP in 230kV Korattur, 230kV OPG-1 & 230kV OPG-2 feeders on Completed. 2. High impedance BBP relay will be replaced by Numerical relay. ---, at 22:14 Bus Bar Protection (Zone1) of 230kV Bus-A got operated at Alamathy Station during fault in 230 kv Alamathy-OPG- 1 feeder. Status received vide mails dated & & & Completed 2. High impedance BBP relay will be replaced by Numerical relay ) TANTRANSCO informed that Numerical BBP would be provided by April, TANTRANSCO mail received on : 1. Complied. 2. High impedance BBP relay will be replaced by Numerical relay. Timeline: April Page 27 of 34

38 64/1/4 Complete outage of North Chennai TPS STG at 23:14 Tripping of evacuating lines due to fault led to tripping of running Unit at NCTPS Stg-1 1. TANTRANSCO to take steps to complete insulator replacement works on the 230 kv lines owned by them in NCTPS area within 6 months. 2. TANTRANSCO to take steps to implement A/R on all 230 kv lines emanating from NCTPS-I at the earliest. TANTRANSCO Status received vide mails dated & & : 1. All the Porcelain insulators were replaced with Polymer insulators in 230kV NCTPS-I - Tondiarpet feeders - 1 & Completed 2. AR will be implemented on all 230kV lines emanating from NCTPS-I. --- Status received vid dated : 1. Completed 2. The scheme needs modification to enable AR, since AR was not envisaged for this station during commissioning. AR will be implemented on all 230kV lines emanating from NCTPS-I within six months ) TANTRANSCO informed that A/R would be implemented on all 230 kv lines emanating from NCTPS-I by June, TANTRANSCO mail received on : 1. Complied. 2. The scheme needs modification to enable AR, since AR was not envisaged for this station during commissioning. AR will be implemented on all 230kV lines emanating from NCTPS-I within six months. Timeline:June Page 28 of 34

39 Kerala 44/I/1 Complete outage of Idukki Hydro Power Station (GD-1) at 12: kv breaker of unit-3 at Idukki Power Hrs 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 Pallom 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 PH: - Generation wing is planning to purchase new transformer 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 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 Replaced. --- Completed. 3. PLCC equipment Tested and found OK --- Completed. 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. --- KSEB Mail dated : 1.Generation wing is planning ti provide low impedance REF protection by retrofitting numerical ABB make transformer management relay in the existing panel. --- KSEB Mail dated : 1. On consultation with OEM, it was understood that the retrofitting of numerical ABB make transformer management relay in the existing panel is not possible. Generation wing is planning to change the panels as part of RMU and is scheduled to start from January'18 beginning. --- Page 29 of 34

40 58/I/1 (GD) Complete outage of 220 kv Kalamassery Substation at 11:20 Triggering incident was conductor snapping in 110 kv Kalamassery- Kaloor feeder KSEB to take steps to provide the following at their 220/ 110 kv Kalamassery SS: 1. Busbar protection at 110 kv level 2. Connecting 220 kv and 110 kv sides on to a common earthmat 3. Redundant DC supply for both protection (220 V) and communication (48 V) applications KSEB KSEB Mail received vide dated : kv bus bar protection progressing Connection of 220kV earth mat and 110 kv plate earthing system completed.---- Completed 3. Redundancy of 110V DC system in progress. Complete independent redundancy is not practical for the time being. 48 V DC redundancy was already there Instead of stand alone event logger, SCADA system of 110 kv feeder is expected to be completed by the end of SCADA system of 220kV side will be taken up after that Stand-alone Event Logger KSEB Mail received vide dated : kv bus bar protection is under progress Completed 3. Redundacny of DC supply for both 110kV and 48v. Provided separate DC source (Redundant) for protection of 220kV feeders and transformers. 48V DC redundacy is already there. --- Completed 4. Stand-alone 'event logger:- Numerical relays with time synchronization is available at 220kV substation Kalamassery and DRand El is downloaded from these relays. KSEBl is not following Stand-alone event logger for substation. --- Completed Status received vide mail dated : 1. Detailed engineering of the scheme has been completed. Material procurement is in progress , Completed 4. The SOE and DR are available with time stamping from the numerical relays. Hence stand alone event logger is not necessary Completed 71/II/6 Multiple trippings at 220 kv Madakkathara at 14: kv Madakkathara-Malaparamba feeder tripped at Madakkathara end due to Y-phase to ground fault. LBB protection trip acted and resulted in tripping of 220kV Bus-1 KSEBL to furnish LBB scheme drawing showing various interconnections, and KSEB Yet to be informed confirm if resetting of LBB relay is implemented through self-resetting contacts of the distance relay. 55/II/9 Tripping of HVDC Gazuwaka pole at 11:41 Pole tripped on operation of differential current protection of east side of Pole-2 PGCIL (SR-I) & PGCIL (SR-II) PGCIL (SR-I) to take up the issue of differential protection operation of converter transformer on low voltage fluctuations with their OEM, and submit a detailed report on it. PGCIL (SR-I) PGCIL-SR1 Mail dated & Review Meeting dated : Issue taken up with OEM and still under study. Till now the OEM could not explain the reason for the said operation of protection. All data has been shared with OEM and further perused to identify the cause of the same and remedial action. 56/II/11 Tripping of HVDC GazuwakaPole at 5:20 Hrs HVDC Pole-2 got tripped on operation of Bus differential protection PGCIL (SR-I) to get the tripping of HVDC Pole-2 tripping on Win-Bus differential protection thoroughly investigated for correctness of operation, and submit a report thereon. PGCIL (SR-I) PGCIL-SR1 Mail dated & Issue taken up with OEM and still under study. Till now the OEM could not explain the reason for the said operation of protection. All data has been shared with OEM and further perused to identify the cause of the same and remedial action. 65/II/15 Tripping of HVDC Gazuwaka Pole-1& at 09:45 HVDC pole-1 got tripped due to operation of South filter inter zone protection and HVDC pole-2 got tripped due to operation of differential protection PGCIL (SR-I) to furnish detailed report on the events that led to tripping of HVDC Poles 1 & 2 including remedial measures taken to PCSC forum. Further, the OEM report w.r.t. tripping of HVDC Pole-2 shall also be furnished. PGCIL (SR-I) PGCIL (SR-I) Mail dated & Issue taken up with OEM and still under study. Till now the OEM could not explain the reason for the said operation of protection for Pole 2. All data has been shared with OEM and further perused to identify the cause of the same and remedial action thereof if any. 67/II/5 Tripping of HVDC Bhadravati Pole at 10:59 Pole-1 tripped due to PC1 INTERNAL MINOR ALARM WEST - ALARM. Pole protection extended trip without any protection operation PGCIL (SR-I) in coordination with PGCIL (WR-I) to take up the issue with its OEM, and furnish the reasons for Pole-1 tripping along with remedial measures taken. PGCIL (SR-I) PGCIL (SR-I) was asked to take up the sissue with PGCIL (WR-I) and furnish action taken report by /II/6 Tripping of HVDC Bhadravati Pole at 14:43 Pole-1 tripped due to PC1 INTERNAL MINOR ALARM WEST - ALARM. Pole protection extended trip without any protection operation PGCIL (SR-I) in coordination with PGCIL (WR-I) to take up the issue with its OEM, and furnish the reasons for Pole-1 tripping along with remedial measures taken. PGCIL (SR-I) PGCIL (SR-I) was asked to take up the sissue with PGCIL (WR-I) and furnish action taken report by Page 30 of 34

41 68/II/8 Tripping of HVDC Gazuwaka Pole-1 & Pole at 17:30 HVDC Poles 1 & 2 got tripped due to Auxilliary supply failure PGCIL (SR-I) to study the solution proposed by ABB in their paper on Mitigation of Ferro-resonance in Line Commutated HVDC Converter Interconnected with Series Compensated Overhead Line Transmission System presented in 2016 IEEE Electrical Power and Energy Conference (EPEC) for implementation feasibility, and furnish an Action Taken Report w.r.t. the same. PGCIL (SR-I) PGCIL-SR1 Mail dated : Ferro resonance is being observed at GWK for any disturbance at Jepore end. ABB have suggested to keep FSC in service at Jeypore end when powerflow is more than 250MW per line. At low powers FSC is generating resonanting frequencies & causing ferro resonance. If SRPC advises, the FSC shall be kept out for powerflow below 500 MW as a mitigation measure to avoid ferro-resonance. PGCIL (SR-I) was requested to refer the solution propsoed to their Corporate for implementation feasibility. It was also made clear to PGCIL (SR-I) that any issue relating to revision of FSC settings can be directly taken up with NLDC. 68/II/12 Tripping of 400 kv NPS Nellore-PG D/C line at 18:58 Lines tripped during a fault on 400 kv Nellore-PG Vijayawada line-2 1. For the 400 kv Nellore-PG Vijayawada line, PGCIL (SR-I) to investigate the reasons for 3-ph tripping of Main-CB upon detection of the fault without trying for A/R and operation of Stub/ Tee protection at the time of Tie-CB A/R attempt at Vijayawada end during instant trippings, and furnish remedial measures taken to address the issues involved. PGCIL (SR-I) PGCIL-SR1 Mail dated & Due to CSD contractor problem CB Y-pole reclosed & defective contactors replaced & wiring problem in CSD rectified on next day -- - Completed. 2. PGCIL (SR-I) to test the recently commissioned CSD s at their 400 kv Nellore- PG SS at the earliest and ensure their correct operation. 3. NPS end DR & EL configured as suggested. --- Completed. 3. PGCIL (SR-I) to configure DR s and EL s of Distance Protection Relays at Nellore- PG with suitable LEGENDs for indicating operation of type of protections (like Zone-1, Zone-2, Zone-3, DEFR, OVR-I, OVR-II, etc.). 70/II/6 Tripping of 400 kv Nellore-PG - NPS line Line tripped due to mal-operation of differential relay at at 13:06 NPS end and was in service from Nellore. For the subject line, PGCIL (SR-I) to configure DR s & EL s of Line Differential Relays for recording all requisite protection operations at their Nellore PS. PGCIL (SR-I) Yet to be Informed at 14:26 70/III/4 Tripping of 400 kv Ramagundam- Chandrapur line at 13:17 R-phase to earth fault had occurred in line. line autoreclosed at Ramagundam end PGCIL (SR-I) to furnish an action taken report on the reasons for A/R nonoperation PGCIL (SR-I) Yet to be Informed at Chandrapur end including remedial measures taken to PCSC forum. 71/II/3 Tripping of HVDC Gazuwaka Pole at 19:29 Pole-2 got tripped due to failure of Valve Cooling system VFD (Variable Freq Drive control) PGCIL (SR-I) to furnish reasons for VFD-1 failure in the instant tripping, and share PGCIL(SR-I) Yet to be Informed OEM s observations w.r.t. the same, along with remedial measures proposed. Page 31 of 34

42 Others 54/I/1 Complete outage of 230 kv S.P.Koil at 17:08 B-phase CT failure occurred in 230 kv S.P.Koil - MAPS line- 1.MAPS to furnish a detailed report on the tripping of SP Koil MAPS lines 1 & 2 NPCIL (MAPS) Station of TANTRANSCO 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. 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. 3.MAPS, in co-ordination with SP Koil, to carry out PLCC end-to-end testing, on SP Koil MAPS lines 1 & 2, and ensure healthiness of PLCC communication & carrieraided protection. 4.MAPS to put in service Auto-Reclosure feature on all four 230 kv lines emanating from MAPS by June, Status revided vide MAPS mail dated ; 1. The settings given by M/s TANTRANSCO were adopted for Main I & Main- II relays for both the lines. The same settings were verified to be same. Subsequently calibrated was done and no drift was observed. --- Completed 2. From May 2016 onwards, the DR, EL and trip report are being sent by mail to SRLDC, Bengaluru by MAPS. --- Completed 3. Monthly maintenance of PLCC equipments is being done by M/s TANTRANSCO. At present PLCC telephone is not working, it is being followed up. --- Completed 4. CVTs are planned to be procured from M/s TANTRANSCO by the end of February 2017 and A/R will be implemented for all the lines emanating from MAPS by July-2017 as discussed in the current SRPC meeting on 25/11/ Status received vide MAPS mail dated & Review Meeting dated ; The CVTs procurement is in progress and the scheme (A/R) would be implemented before Page 32 of 34

43 62/III/2 Tripping of 400 kv Kaiga-Guttur line at 05:01 B-phase to earth fault. Line did not auto-reclose at Kaiga end. 1. KGS to properly configure all relays DR s time scale for a post-triggering period of 2 sec to capture events such as complete A/R operation. 2. KGS to ensure time-synchronization of all protection relays with GPS in their 400 kv switchyard. NPCIL (KGS) Status received vide mail dated & 1. All 400kv transmisisonlines relays DR time scale for a post-triggering period of 2 sec is implemented. ----Completed 2.Time-synchronization for all lines protection relays (M1 &M2) with GPS in their 400 kv switchyard is being implemeneted. Scheme design is in process. ECD-April /II/7 Tripping of 400kV JSWEL - Guttur line at 18:02 & at 02:05 Line tripped on operation of Over Voltage, Stage-1 protection at Guttur end and Direct Trip was received at JSWEL. JSWEL to configure their end DR s and EL s for DT receipt/ send event for 400 kv JSWEL Status received vide mail dated JSWEL Guttur line. JSWEL will configure DR s & event lists for DT send/ Receipt for 400kV JSWEL-Guttur Line during next opportunity / outage in concurrence with Guttur end. It was noted that no JSWEL representative had come to the meeting. The issue was discussed, and it was decided that JSWEL would complete the recommended work by the end of December, /II/11 Tripping of 400 kv K V KOTA - HNPCL lines 1 & at 22:36 Line-1 tripped on R-E Zone-1 fault, and the Line-2 tripped on Direct Trip receipt at KV Kota end 1. HNPCL to ensure time sync of all of their protection relays with GPS, and to configure corresponding DR s for post triggering time of 2 sec.hnpcl to configure DEF operation only when Distance relay does not sense the fault. 2.HNPCL to ensure healthiness of A/R scheme implemented on all 400 kv lines at their station. HNPCL HNPCL Mail dated : 1. Time synchronization of protection relays and BCU's with GPS completed. As per APTRANSCO recommendations DEF has been switched off in line protection relays HNPCL to provide priority A/R scheme for 400 kv Tie-CB s with s suitable deadtime of say 2 sec. 4.HNPCL to revise PDR timing as 1.5 sec till implementation of A/R for Tie-CB s after which it shall be further revised to 2.5 sec. 3. Line Tie CBs Priority closing has been implemented for all the lines Completed 5.HNPCL to implement following OVR-I gradings for the 400 kv lines emanating from their station: Kalpaka Line A 111%, 10 sec Kalpaka Line D 110%, 8 sec KV Kota Line B 111%, 9 sec KV Kota Line G 109%, 6 sec 69/I/1 Complete outage of 400kV TPCIL station at 19: kv TPCIL-Nellore PS line-1 got tripped from TPCIL end during fault in 400kV Nellore-Nellore PS line-2. Running units at TPCIL got tripped due to loss of evacuating line. 400kV Nellore PG - Nellore PS line-2 and 400kV TPCIL - Nellore PS line-1 were under shutdown. TPCIL to configure DEF protection such that it remains in blocked condition as TPCIL Yet to be informed long as Distance Protection is active, and becomes active only when distance protection does not pickup. Page 33 of 34

44 69/II/9 Tripping of 400 kv Neyvelli TS2 Pugalur and 400 kv Neyvelli TS2 (exp) Pugalur line at 23:54 Protection at NLCTS-2 & NLCTS-2 Exp has sensed as R-Y-E fault and given a 3 phase trip. At Pugalur end protection has sensed fault as Y-N and B-N fault in 400kV Neyveli TS2-Pugalur line & 400kV Neyveli TS2 EXP-Pugalur line respectively. Breaker at Pugalur got tripped due to Direct Trip receipt. 1.For the tripping of 400 kv NLC TS2 Pugalur line, NLCIL to investigate the reasons for sending of DT to Pugalur end, and furnish an action taken report including remedial action taken and setting right various LEGEND issues in DR & EL of protection relays to PCSC forum. 2. For the tripping of 400 kv NLC TS2Exp Pugalur line, NLCIL to investigate the reasons for 3-ph tripping (detection of the fault as Y-B-E) of the line from NLC TS2Exp end including verifying pertinent settings of P437 relay (reference may be made to explanation given by TPCIL in GD - I.1/ GD - I.2), and furnish an action taken report including remedial action taken and setting right various LEGEND issues in DR & EL of protection relays to PCSC forum. NLCIL NLCIL Mail dated : 1. Shut down was taken on 400kV Neyveli TS-II to Pugalur feeder on to check the end-to-end communication for DT/ permissive & other signals by testing at both the ends and to check the healthiness of the PLCC system components. The system was thoroughly checked and the missing loops in the relay circuit (Carrier send in Main1 relay and Carrier receive in Main2 relay) were provided. Omicron test kit was used to create single phase faults and Auto reclose of breaker was checked for both Main1 & Main2 relays. Direct trip command was initiated from both Main1 & Main 2 relays for over voltage.carrier send and received at both Pugalur and Neyveli Ts-II end was found to be proper for both permissive and direct trip commands. Similarly permissive and direct trip commands were simulated from Pugalur end and the same was found to be normal at both Pugalur and Neyveli TS-II end. The level measurement was measured and found to be normal ---- Completed /III/1 Tripping of 400 kv HNPCL- KV Kota line at 12:34 R-phase to earth fault had occurred in line. Breakers at HNPCL to furnish a report detailing the reasons for A/R non-operation in the HNPCL Yet to be informed HNPCL got tripped due to auto-reclose lockout and autoreclose was successful at KV Kota instant tripping, and remedial measures taken to set right them. end. Page 34 of 34

45 I Remedial Measures/ Actions taken for the Critical Tripping Incidents (as on ) Sl.No. Element Name Outage date/time Revival date/time Reason for Outage Sender/ Receiver Remedial Measures/ Actions taken 400 Kv NTPL - TTRNPS /12:01:00 TRIPPED ON R-B-N FAULT NTPL/ PGCIL (SR-II) PGCIL (SR-II): Line Auto Reclosed and tripped due to persisiting Fault. It was gathered that problem at NTPL Switch Yard. 1 PGCIL(SR-II): Line Auto Reclosed and tripped due to persisiting Fault. It was gathered that problem at NTPL Switch Yard (In B-ph Gas Insulated Bus Duct IR value observed to be zero and Sf 6 leakage observed at NTPL GIS.) NTPL: kV VTPS -MALKARAM /10:45: /11:51:00 DT RECEIVED APGENCO/ TSTRANSCO TSTRANSCO: Tripped at Both ends. Tripped on Direct Trip received indications at Malkaram end. Other end tripped on Over Voltage. 400KV/220KV DICHPALLY-ICT /10:23: /14:58:00 To take IR values TSTRANSCO TSTRANSCO: Line Clearance was taken on ICT-3 and IR testing of windings, CTs Tan delta testing was done as part of periodical maintenance KV-MALKARAM-VTPS_IV /14:39: /15:42:00 MAL-OPERATION TSTRANSCO/ APGENCO TSTRANSCO: Line is in service at Malkaram end. APGENCO: 5 400KV-LKPPL_STG2-VIJAYAWADA /10:53:00 swapping. LANCO/ PGCIL (SR-I) To-be-discussed 400KV-MAMIDAPALLI-DINDI /11:29: /11:52:00 RELAY MALOPERATION TSTRANSCO TSTRANSCO: Direct trip was sent from Dindi to Mamidipally SS while maintenance officials were checking the panels 6 at Dindi end. Instructions were given to be careful while checking the panels of in service feeders. 400KV-BTPS-YTPS /06:17: /07:11:00 TRIPPED ON B-N FAULT KPCL KPCL: line tripped on operation of Zone-1 Protection due to C-Phase to ground fault. Line had auto reclosed 7 immediately but auto reclose locked out due to persistent fault KV/220KV VEMAGIRI_AP-ICT /06:58: /08:32:00 TRIPPED DUE TO B-N LINE APTRANSCO APTRANSCO: Back up O/L and E/L protection shall be tested for ensuring healthiness of the relays. 400KV/220KV HOODY-ICT /17:42: /18:34:00 OVER FLUX PROTECTION KPTCL To-be-discussed 400KV-KTPS_VI-KHAMMAM /12:14: /12:47:00 MAL-OPERATION TSGENCO/ PGCIL (SR-I) To-be-discussed 400KV-KOLAR_AC-HOODY /17:42: /02:32:00 LIGHTENING ARESTER PGCIL (SR-II)/ KPTCL To-be-discussed Page 1 of 3

46 I KV CHITTOOR-SRIPERUMBADUR /01:02:00 TRIPPED ON B-N FAULT APTRANSCO/ PGCIL (SR-II) APTRANSCO: Retrofitting of relays done recently KV-HOODY-NELAMANGALA-1 400KV AC L /18:35:00 R-PHASE LIGHTNING KPTCL To-be-discussed ARRESTER NELAMANGALA END KV/230KV NEYVELI_TS_II-ICT /21:36:00 TRIPPED ON SPARK IN NLCIL To-be-discussed BUSHING KV-AMBEWADI-PONDA-2 220KV /10:41: /11:07:00 TRIPPED ON A PHASE TO KPTCL/GED To-be-discussed GND FAULT KV/220KV GAJWEL-ICT /16:13: /16:49: KV BUS BAR TSTRANSCO To-be-discussed PROTECTION OPERATED KV-GAJWEL-RAMAGUNDAM /01:13:00 D/T RECEIVED AT GAJWEL TSTRANSCO/ NTPC- To-be-discussed END RAMAGUNDAM KV-KOCHI-TRICHUR /18:01: /18:33:00 TRIPPED ON B-N FAULT PGCIL(SR-II) To-be-discussed KV-MAMIDAPALLI-KHAMMAM /15:26: /16:11:00 TRIPPED ON B-N FAULT TSTRANSCO/ PGCIL (SR-I) PGCIL(SR-1): Line tripped on B-N fault. Fault distance: 75.42kms, FC: 4.180kA from KMM end. Distance: 173.2kms, FC: 1.464kA from Mpally end. Main CB & Tie CB A/R attempted 1st time & successful at KMM end. For fault during reclaim time, line tripped. Line belongs to TSTRANSCO. TSTRANSCO: KV-SULURPET-GUMMIDIPOONDI /13:50: /14:20:00 TRIPPED ON R-N FAULT APTRANSCO/ TANTRANSCO TANTRANSCO: Feeder was charged at Gummidipoondi end at 14:20. on KV-SULURPET-GUMMIDIPOONDI /14:30: /14:40:00 POLE DESCRIPENCY APTRANSCO/ TANTRANSCO TANTRANSCO: Feeder was charged at Gummidipoondi end at 14:20. on KV-NELAMANGALA-HASSAN /16:02:00 TRIPPED ON R-N FAULT KPTCL/ PGCIL (SR-II) To-be-discussed KV/220KV PAVAGADA-ICT /15:09: /18:06:00 HAND TRIPPED AFTER IDLE CHARGE PGCIL (SR-II) To-be-discussed KV-NELAMANGALA-HASSAN /14:22:00 TRIPPED ON B-N FAULT KPTCL/ PGCIL (SR-II) To-be-discussed 400KV-SRISAILAM_LEFT_BANK-DINDI /07:08:00 TRIPPED ON Y-N FAULT TSGENCO/ TSTRANSCO To-be-discussed KV/220KV DINDI-ICT /15:48: /19:56:00 Winding Resistance measurement TSTRANSCO To-be-discussed KV-GOOTY-NPS /16:30: /16:45:00 TRIPPED ON LBB OPERATION PGCIL (SR-I) To-be-discussed 400KV-VALLUR-ALAMATHY /17:31: /19:30:00 Bph LA Failure at Almaty end NTECL/ TANTRANSCO To-be-discussed 400KV-NELAMANGALA-HASSAN /15:21:00 B PHASE TO GROUND KPTCL/ PGCIL (SR-II) To-be-discussed KV-KTPS_VII-KHAMMAM /13:04: /13:27:00 Tripped at KTPS end on B-N Fault TSGENCO/ PGCIL (SR-I) To-be-discussed KV-TIRUNELVELI-EDAMON-1 220KV /14:58: /18:58:00 LA FAILURE AT EDAMON END PGCIL (SR-I)/ KSEBL To-be-discussed Page 2 of 3

47 I KV-KAIGA-GUTTUR-1 400KV /17:30: /19:44:00 TO ATTEND FAULT IN LINE 2 NPCIL (KGS)/ KPTCL To-be-discussed 220KV-YERRAANDAHALLI-HOSUR_TN-1 220KV /01:41: /02:53:00 BUSBAR PROTECTION OPERATED AT HOSUR END KPTCL/ TANTRANSCO To-be-discussed 400KV/220KV DINDI-ICT /14:45: /17:25:00 OIL LEAKAGE TSTRANSCO To-be-discussed 400KV-NAGARJUNASAGAR_PG- MEHBOOBNAGAR-1 400KV /00:28: /01:05:00 AUTO RE-CLOSURE OPERATIONAL PGCIL (SR-I)/ TSTRANSCO To-be-discussed 400KV-MUNIRABAD-RTPS /10:17: /11:26:00 BREAKER LOCKOUT PGCIL (SR-I) To-be-discussed 400KV-NELAMANGALA-TALGUPPA /16:04: /18:16:00 TRIPPED ON R-N FAULT KPTCL To-be-discussed 400KV-NELLORE_PG-VIJAYAWADA /01:37: /03:13:00 TRIPPED ON R-Y FAULT PGCIL (SR-I) To-be-discussed 400KV-KAIGA-GUTTUR /17:23: /18:42:00 DT RECEIVED AT KAIGA END NPCIL (KGS)/ KPTCL To-be-discussed 400KV-GOOTY-NARNOOR /07:20: /08:46:00 TRIPPED ON Y-N FAULT PGCIL (SR-I)/ APTRANSCO To-be-discussed 400KV-GHANAPUR-MAMIDAPALLI /12:23:00 LOAD MANAGEMENT PGCIL (SR-II)/ TSTRANSCO To-be-discussed KV-KTPS_VI-KTPS_VII /18:11: /02:05:00 H/T due to heavy spark near Bus2 TSTRANSCO To-be-discussed KV-AMBEWADI-PONDA /13:51: /14:12:00 DISTANCE PROTECTION KPTCL/ GED To-be-discussed Page 3 of 3

48 Annexure-IV TRANSMISSION CORPORATION OF TELANGANA LIMITED From To The Chief Engineer The Member Secretary, Power Systems SRPC, TSTRANSCO, 29, Race Course Road Vidyuth Soudha, Hyderabad. Bangalore Lr.No.CE/PS/SEPS/SP2/211/Relays C /Vol- 208/D.No.33/18, Dt: Sir, Sub:- TSTRANSCO- Implementation of SPS on 220kV HIAL Sivarampally, 220kV Mamidipally Sivarampally and 220kV Shankarpally Gachibowli feeders-1&2 Submission of SPS scheme proposals at 220kV Sivarampally and 220kV Gachibowli substations to SRPC Approval Requested-Reg. *** The following 220 kv feeders are getting overloaded during (N-1) contingency kV HIAL Sivarampally kV Mamidipally Sivarampally kV Shankarpally Gachibowli feeders kV Shankarpally Gachibowli feeders-2 In view of safety of grid and to avoid cascade tripping of above lines during contingency, TSTRANSCO has proposed for implementation of SPS scheme at 220kV Sivarampally and 220kV Gachibowli substations. The SPS scheme is formulated duly conducting the load flow studies with an anticipated Telangana grid demand of 10,000MW and with the identified loads and elements to be tripped when the line loadings are exceeding the limits as mentioned below at 220kV Sivarampally and 220kV Gachibowli substations and are enclosed in ANNEXURE-I and ANNEXURE-II respectively to bring the line loadings below the emergency loading limits. The sequence of events and load flows on various elements in and around 220kV Sivarampally and 220kV Gachibowli substations due to operation of SPS scheme during (N-1) contingencies are tabulated in the enclosed ANNEXURE-III. The details of proposed SPS schemes are as follows. Whenever the load on subject feeders exceeds the 97%, 98% and 100% of emergency thermal loading limit of Zebra conductor (i.e., 616A as per CEA planning criteria Jan 2013) the identified loads/elements shall trip in STAGE-I, STAGE-II and STAGE-III with respective stage wise time delays duly utilizing the following. Contd::2:: Page 1 of 9