PCM’s Mailing List 1) Chief Engineer (LD), MSETCL, Kalwa. Fax-27601769/65 2) Chief Engr. (Trans O&M), MSETCL, Bandra. Fax No. 022 - 26590808/26598587. 3) CE (W), MSEGCL, 3rd floor, Prakash gad, Mumbai. 4) S.E. (T&C), MSETCL, Aurangabad Fax-0240-2234220 /2346290 5) S.E (T&C), MSETCL, Pune. Fax-9520-2617532/2612342 6) Dy. CE (T&C), MSETCL, Koradi, Nagpur. Fax- 07109 - 262162 7) S.E.(T&C), MSETCL, Vashi Fax- 022-27656039 8) S.E.(Testing), Bhusawal, Dist: Jalgaon Fax-02582-250379 9) S.E. (Task Force), MSPGCL, Nagpur Fax- 0712-2591717. 10) S.E.(TCC), MSETCL, Karad. Fax.No. 02164 255118 11) Chief Engineer (Gen), GSECL, H.O. Baroda. Fax-0265-5512129/2344537 12) S.E. (Testing), GETCO, Baroda. Fax-0265-2351218 13) Chief Engineer (LD), MPPTCL, Jabalpur, Fax - 0761- 2664343 / 2970119. 14) E.D. (T&C), MPPTCL, Jabalpur. Fax-0761-2702710 15) ED (Engg.) MPPGCL, Jabalpur Fax- 0761-2660063 16) Chief Engineer (LD), CSPTCL, Raipur. Fax-0771 - 2574174 17) C.E. (T&C), CSPTCL, Raipur.Fax-0771-2574749 18) EE (T), CSPGCL- Fax.No. 07789-226227 19) S.E. (T&C), CSPTCL, Bhilai. Fax.No. 0788 - 2281561 20) S.E. (T&C), CSPTCL, Raipur. Fax No.0771 - 2574749. 21) EE, Division VIII (MRT), Elect. Dept; Goa Fax 0832-2735124. 22) SE, Electricity Dept., DNH, Silvasa. Fax : 0260-2642338 23) Executive Engr., Electricity Dept. DD. Fax: 0260-2250889 24) D.G.M. (O.S. ),N.T.P.C., Mumbai, Fax- 28216692 25) DGM, NTPC WR – II, Raipur, Fax: 0771 - 2544550 26) D.G.M. (EM), KSTPS, NTPC, Korba Fax 07759-233088 (Tele fax: 232440) 27) DGM (EMD), VSTPS, NTPC, Vindhyachal Fax-07805-247713 28) DGM (EM-I), NTPC, SIPAT Fax-07752-246506 (Tele fax: 246691) 29) AGM (O&M), KGPP, Adityanagar, Surat Fax 0261-2861428/2861433 30) Sr.Supdt. (EM), Gandhar, NTPC Fax-02642-87402 / 87450 31) DGM (O.S.), WRLDC, Mumbai Fax-28235434 32) DGM, WRTS-I, POWERGRID, Nagpur, Fax- 0712- 2631051 / 641366 33) AGM, WRTS-II, POWERGRID, Baroda Fax-0265-2480952 (Tele fax: 2487542) 34) SME (E), TAPS-3&4,Tarapur Fax 02525-282001/282073 35) Maintenance Superintendant, TAPS –1 & 2, Tarapur.Fax- 02525-282121 36) SME(E), NPCIL , Kakrapara Fax 02626-234266 37) GM (Maint.). TORRENT Power., Ahmedabad.Fax-079-27506679 38) AGM (QAIT), TPC, Trombay. Fax –022-66687088 39) Asst. VP, Dahanu TPS Fax- 952528-222576 / 222039 40) GM (O & M), Reliance Infrastructure Limited, Mumbai Fax-30094488 41) GM (Electrical), JPL, Raigarh, Fax. No. 7767-281995, 281993. 42) AGM (OS), NSPCL, New Delhi . Fax.No.011 26717381/26717363/26717366 43) Vice President, APL, Ahmedabad 079-25557176 44) GM, RGPPL, Anjanwel, Guhagar, Ratnagiri, Fax.No. 02359 241071 45) GM, JSW Energy Ltd., Jindal Mansion, Mumbai- Fax.No.022 23526400 46) GM, CGPL, Mundra Fax.No. 02838 661188 47) Director (G M Division), CEA, New Delhi. Fax.No.011-26109750 Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014 1.0 Introduction: Two separate events occurred at about 1910 and 1921 hrs on 12.03.2014 at 400 kV Chorania s/s. During the latter event there was tripping of all the CGPL running units. The grid also experienced a large drop in frequency. Special meetings were held on 19.03.2014 and 21.03.2014 at WRLDC, Mumbai and CGPL Mundra respectively to discuss and analyze the occurrence of 12.03.2014 in the GETCO/CGPL system. Based on the discussion and data submitted for analysis, the following report is prepared. The list of participants is enclosed at Annexure-I. 2.0 Antecedent Conditions The antecedent conditions at about 1900 hrs of 12.03.2014 were as below: System Frequency: 49.95 Hz ALL INDIA PARTICULARS Region WESTERN REGION PARTICULARS Demand met (MW) State Demand met (MW) NR 32,453 Maharastra 15,129 WR 36,033 Gujarat 10,551 SR 35,103 Madhya Pradesh 6,213 ER 15,537 Chattishgarh 2,854 NER 1,874 Dadra & Nagar Haveli ALL INDIA 625 1,21,005 Daman & Diu 244 Goa 340 Following transmission lines in the vicinity were under forced outage in the antecedent conditions 400 kV Bachau –Ranchodpura (Vadavi)-II since 13:38 hrs of 12.03.2014. 220 KV Bachau-Halvad D/C since 22:50 hrs of 16.02.2014 (due to tower collapse) The injection at CGPL was around 3750 MW and the loading of transmission lines from CGPL Mundra was as follows: 400 kV Mundra – Bachhau D/C 400 kV Mundra – Chorania (Limbdi) D/C : 1510 MW (755 MW /ckt) 400 kV Mundra- Jetpur D/C : 1110 MW (555 MW /ckt) : 1144 MW (572 MW/ckt) 400 kV Kosamba-Chorania-1 line was under construction and kept in charged from Chorania end. Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 1 3.0 EVENT DESCRIPTION 3.1 : Event-1 at 19:10:43:273 hrs on 12.03.2014 at 400 kV Chorania s/s: Following two tripping took place at 400 kV Chorania s/s: (i) At 19:10:43:273 hrs of 12.03.2014, 400 kV Chorania-Kosamba-1 at Chorania end (ii) 400 kV CGPL-Chorania-I tripped at both ends. It was reported that B-ph bushing of the Line reactor of 400 kV Chorania-Kosamba-1 at Chorania end failed and caught fire. The fire was extinguished by the fire tender already parked in the substation. Line tripped on reactor differential and distance protection. It was also reported that the NGR LA of the Line reactor of 400 kV CGPL-Chorania-1 at Chorania end failed resulting in tripping of 400 kV CGPL-Chorania-I on operation of Reactor REF protection. There was a direct trip command sent to remote end. However reasons for failure of the NGR LA of this line only, was not clear as other lines have also seen the same stress and LA did not fail. Impact of Event 1: Consequent to the loss of 400 kV CGPL-Chorania-1, the power flow on 2nd circuit of CGPL Mundra-Chorania increased from 752 MW to 980 MW. The power flow on 400 kV CGPL-Jetpur D/C lines increased from 572 to 704 MW each circuit, while the power flow on CGPLBachau D/C lines increased from 561 MW to 692 MW on each circuit. Considering the high loading on the 2nd ckt from CGPL to Chorania and depletion of the network, generation reduction at CGPL Mundra was considered necessary by operators at WRLDC, SLDC-Gujarat, NLDC and CGPL Mundra. WRLDC in consultation with SLDC-Gujarat and CGPL Mundra was exploring the possibility of restoring the 400 kV CGPL-Chorania-1 without Line reactor at Chorania end. Meanwhile another event took place at the same substation, and is as given below. 3.2 : Event-2 at 19:21 hrs at 400 kV Chorania s/s: LBB Operation of Bus-2: While the above actions were being taken up, the following lines connected to Bus 2 of 400 kV Chornia tripped at 19:21:57.273 Hrs on operation of LBB protection of bus-2 at Chorania having Double Main and Transfer Switching Scheme. Following lines tripped due to operation of LBB. a. 400 kV Chorania-Asoj b. 400 kV Chorania-Ranchodpura (Vadavi)-2 Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 2 c. 400 kV Chorania-CGPL-2 d. 400/220 kV ICT-2 at Chorania e. 400 kV Chorania-Amreli S/C The analysis of the protections and operation of LBB is discussed in detail in Annex-2. The outcome of the analysis for operation of LBB and trippings on power swing is as follows: During the fire on the “B” phase of the line reactor of this line, it is suspected that the fire might have spread to control cables and the CT wiring of Main-I or the Bushing CT wires of the reactor and A.C. Auxiliary supply cables might have got damaged. Due to this the A.C supply might have leaked into the CT cables of either Main-II DPS or the reactor bushing CTs (used for line current compensation) and this leakage current of magnitude more than 200mA was extended to the Main-II DPS relay. The master trip relay after the earlier tripping of the line breaker was not resetted. This resulted in satisfying the conditions for stuck breaker condition and operation of LBB relay of this line. Tripping on Power Swing: Subsequently the following additional lines tripped at 19:21:58.150 hrs in Zone-1, on Power Swing a. 400 kV Bachau-CGPL-1 at Bhachau end in Z-1. b. 400 kV Bachau-CGPL-2 at Bhachau end in Z-1. c. 400 kV Jetpur-CGPL-1 at Jetpur end in Z-1. d. 400 kV Jetpur-CGPL-2 at Jetpur end in Z-1. e. 400 kV Bachau-Ranchodpura-1 tripped at Bhachau end in Z-1. f. 220kV Bhachau-Lalpar & Bhachau-Morbi lines at Bhachau end in Z-1. WRLDC have observed that angular separation between CGPL bus with respect to Bhadrawati was seen to sharply increase from 17° (during steady state) to 180° followed by loss of synchronism. However the subtle points to note on the above observation and the Zone-1 power swing seen by the Distance Protection Scheme (DPS) relays on lines at the adjacent buses connected to CGPL, are as follows: (i) A DPS relay would sense Zone-1 fault during a power swing only if the electrical centre of the two buses connected through a line moves into the line section. This is only possible if the angular separation between these two adjacent buses connected through the line moves towards 180°. Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 3 (ii) Since the lines emanating from CGPL have tripped in Zone-1 power swing it implies that the angular separation between the CGPL bus and the adjacent buses was approaching 180° and due to this the electrical centre between these buses and CGPL was moving within these line sections. Hence the lines tripped on Z-1 power swing in about 1 second after event 2. (iii) The observation of angular difference between CGPL and Bhadravati at the point when these lines tripped in Z-1 power swing is estimated to around 72° after one second (the oscillations of the order of 0.2hz was observed between the CGPL & Bhadravati PMU plot) and would reach to 180° after about 2.5 seconds. However this angular separation between far way buses is of no signification in the transient analysis. 3.3 : This led to non availability of evacuation from CGPL leading all units at CGPL to run on house load, except Unit#40 which tripped on SPS operation. After 5-6 mins of operation of Unit#10, Unit#20, Unit#30 & Unit#50 on house load, all these units were hand tripped, except Unit#10 which tripped on HP exhaust hood temp very high. The frequency of the islanded system of CGPL Mundra touched to 52.885 Hz (at 19:21:59:200) and the governor action immediately controlled the frequency. The house load operation could continue only for about six minutes after which there was a blackout at CGPL. With this CGPL was completely out of the grid and collapsed. 3.4 : Impact of event-2 and Actions taken by WRLDC/SLDC: The frequency in the grid rapidly declined and touched 49.285 Hz within 3 minutes due to sudden deficit of 4050 MW. Following actions were immediately by WRLDC taken for system security: a. Koyna hydro, SSP hydro and thermal stations of NTPC (Kawas/Gandhar/Korba/Vindhyachal/Sipat), DGEN (infirm injection) were directed to maximize generation at all the units on bar. One additional units of SSP hydro was also synchronized. b. Power order on HVDC Mundra Mahendragarh Bipole was reduced from 2000 MW to 1500 MW to control the critical loading on 400 kV SSP-Kasor, SSP-Asoj and IndoreAsoj. Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 4 c. Power flow on HVDC Chandrapur-Padghe Bipole reduced from 900 MW to 600 MW to control critical loading on 400 kV Boisar-Vapi line The frequency was brought above 49.8 Hz within 10 minutes of the incident and it was brought within the IEGC band in the next 25 minutes. 3.5 : Restoration of CGPL: Power supply to CGPL Mundra was extended from 400 kV Jetpur line at 19:37 hrs 3.6 : Load Relief during Event-2: The reported load shedding due to operation of d/dt relay as reported by the respective utilities is as under: 4.0 : SUMMARY AND RECOMMENDATIONS : The analysis of the occurrence has revealed several issues that need to be addressed for preventing reoccurrence of such events and for enhancing system security. The summary along with recommendations is as under: i) Failure of reactor of 400kV Chorania-Kosamba line: Failure of “B” phase reactor of 400kV Chorania-Kosamba line No. 1 to be taken up with the manufacturer by GETCO and the report of the OEM to be shared in the next PCM of WRPC. ii) Failure of NGR LA of 400kV CGPL-Chorania line 1 : Regarding the matter of failure of NGR LA of CGL make, POWERGRID shall take up the same with OEM and share the report in the PCM. Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 5 iii) Operation of LBB of 400kV Chorania-Kosamba line No. 1: It is recommended that during fire, all the control wiring fuses of the control panel of the affected element/bay should be removed immediately so as to avoid leakages in damaged cable cores. The immediate resetting of the tripped relays is not possible under such circumstances, since the S/S officials are generally busy controlling the fire. iv) Load Relief Related: It was observed that the rate of fall of frequency at different locations in the grid depends on the stiffness of the point w.r.t. to the point of disturbance in the grid (where generation loss had occurred). Therefore the rate of fall of frequency in MP, Chattisgarh which are electrically far away from Mundra would be lesser than in Gujarat or Maharashtra. It was therefore recommended that since UMPPs and large generating stations are located in Gujarat and Chattisgarh States more quantum of load shedding should be wired up through df/dt relays in Gujarat and Chattisgarh State. Further the rate of df/dt in Gujarat system for the first stage is set at 0.2Hz/sec, therefore Gujarat should explore to set the first stage at 0.1Hz/sec. These may be discussed in the next PCM. v) Governor response of generators in NEW Grid : The loss of 4000 MW at 19:22 hrs during the evening peak hours led to drop in frequency of 0.67 Hz. Considering the load loss of 1100 MW, the system inertia comes out to be around 4300 MW/Hz without considering the frequency dependence of load and governor response. Thus the automatic response through FGMO/RGMO from rest of the generators on bar in the grid was inadequate. It was recommended that all generating units mandated for RGMO/FGMO in Western Region should furnish plots of Active power vs frequency available/recorded during the period 1920 to 1930 hrs of 12.03.2014 at the generating stations to WRLDC and WRPC by 22.04.2014. Necessary co-ordination may be done by WRLDC for getting the above data and a white paper on the same shall be published by WRLDC. Also Utilities shall submit complete details of governor setting of the generating units mandated for RGMO/FGMO to WRLDC. WRLDC shall compile this data for ascertaining the frequency response of the generators during either the frequency rise or frequency fall cases. vi) Tripping of lines in Z-1 power swing: After the operation of LBB protection the evacuation from CGPL got depleted and resulted in setting up of power swings in the system. The lines connected to CGPL Mundra subsequently tripped in Z-1 due to the power swing, before the generators at CGPL Mundra fell out of synchronism (even Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 6 before the first pole slip) with the rest of the grid generators. As per the existing protection philosophy power swings entering in Z-2 & Z-3 are blocked and power swings entering in Z-1 of DPS are allowed to trip the line due to the severe nature of power swings entering in the Zone-1. Therefore Z-1 philosophy adopted for tripping the lines in Z-1, connected to the generating stations and lines nearby the vicinity of generating stations which are supposed to power swings needs to be discussed in the PCM. Under such circumstances the possibility of using out of step protection relay as an alternative to tripping a line in Z-1 power swing requires to be deliberated in the PCM. This incidentally has also been raised by the Hon’ble commission CERC in its order on the grid disturbances of 30th & 31st July 2012. vii) Dynamic Compensation: There is a need to simulate the events and run transient stability studies to see the anticipated governor response, df/dt enhancement and also suggest measures to improve the dynamic stability. For this the event-2 data of the grid requires to be collected, simulated and examined from transient stability point of view. It is proposed that this may be studied by academic consultant like IIT-B. Also it is desirable that WR Study Committee members avail academic training to be able to conduct such special studies frequently. For the WR part, WRLDC shall collect the governor response and submit white paper as mentioned above. However since the entire grid is now synchronous, the governor response in other regions also desires to be studied. For which WRLDC may take up with NLDC. Hence WRLDC may also collect the snapshots of outside WR (by co-ordinating with NLDC) of the system conditions. The incident data of PMUs and SCADA data, and other relevant data like all India data along with governor response can then be taken up for simulation. viii) GPS Synchronization: The time stampings on the DRs generated during the above occurrence did not coincide and there was quite a large time drift. GPS time synchronization of the relays shall be carried out. The methodology/procedure for carrying out the synchronization may be discussed in the next PCM. ix) Restoration of 400kV Bhachau (PG)-Ranchodpura line No.2: This being important line, efforts should have been made to restore the same at the earliest. It was informed by POWERGRID that permission was not given by WRLDC for test charging the line after it tripped on transient fault. WRLDC informed that since the line tripped on R-B (line to line) fault, therefore permission for second attempt of charging the line was not granted. It was observed that the line rarely trips for permanent nature of phase to phase involving R & B phases (R & B phase lines are Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 7 physically located at the either side of the tower). While the concern of WRLDC was noted, system operator should accept the fact that the declaration of healthiness of the transmission element is the prerogative of the utility responsible for maintaining that element. Hence priority should be given to charging the line, and not insist on getting DR etc. DR and other analysis are post-facto in nature, if the past record/experience of the utility is satisfactory. This would help earlier restoration of the element, since the utility is the best judge of real conditions existing in the field. x) 400kV Chorania-Kosamba line No. 1 line charging: The line was kept in charged condition, without informing WRLDC resulting in confusion regarding failure of reactor, as it took some time to ascertain that the line reactor of this line had failed. Simultaneously, 400kV CGPL-Chorania line 1 also tripped on reactor REF resulting in confusion as to which line reactor has caught fire. Charging any element which has bearing on the regional system shall be informed to WRLDC before charging the element. xi) PMU Wiring up at CGPL: The PMU data was not sufficient to analyze the occurrence. Instead of wiring the current input of Unit#40 of the CGPL, line currents of Bhachau lines would have been more useful. xii) Proposed Changes in SPS at CGPL Mundra : Following changes at Sr.No.1 in the approved SPS table (enclosed at Annexure-III) were recommended for immediate implementation, after due deliberations and were agreeable to all the concerned. As regards to revision in the existing SPS at CGPL, after detail deliberations, following modifications in the existing SPS were suggested; The existing SPS may be replaced by Option-A : i) If line loading on any line exceeds 900MW back down generation at CGPL. ii) If line loading on any line exceeds 1200MW trip one unit at CGPL. Option-B : i) For loss of any two lines trip one unit at CGPL. ii) For further loss of any two lines trip another unit at CGPL. Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 8 CGPL representative requested that they are in agreement for modification of the conditions in view of the threat to grid and also this would help survival of their units. However, the scheme should be validated through studies and tripping of units unnecessarily should be avoided, since tripping of large units not only impacts the grid but also the units are stressed. Also the utilities responsible for maintaining the transmission system for evacuation should maintain the transmission lines, so that such that multiple tripping of lines do not occur. CGPL further proposed that generation backing down would be carried out to the tune of 800MW, if any one line out of the six outlet lines trips, further generation backing down of 800MW would be carried out if second line tripes subsequently. WRLDC was of the view that backing down is a slow process and under the circumstances quick actions are required and therefore option-A & option-B are the most appropriate options to deal with the situation. SLDC GETCO also expressed similar views. It was therefore recommended that CGPL would review the above options and send their comments at the earliest for implementation of Option-A or Option-B as given above. xiii) Interim Scheme for immediate implementation: PGCIL to extend signals of MW or tripping, preferably MW, to CGPL, so that the existing scheme may be modified as per enclosed Annexure-3. ************** Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 9 Annexure-I Participants list for Special meeting (CGPL) held on19.03.14 at WRLDC, Mumbai Sl.No. Name 1 Shri S.D. Taksande 2 Shri Satyanarayan S. 3 Shri M.M. Dhakate 4 Shri P.D. Lone 5 Shri L.K.S. Rathore 6 Shri Shiva Suman 7 Shri B.B. Mehta 8 Shri J.N. Pancholi 9 Shri P. Mukhopadhyay 10 Shri V.K. Shrivastav 11 Shri Abhimanyu Gartia 12 Shri Anand Dubey 13 Smt. Pushpa S. 14 Shri Vivek Pandey 15 Shri Awani Rai 16 Shri Aditya P.Das 17 Shri N. Nallarasan 18 Shri R.M. Sankhe 19 Shri Vipul Raval 20 Shri K.N. Athavale Designation M.S. S E (Comml.) S.E.(Opn.) E E (Comml.) EE(Opn.) A D (Comml.) C. E. O.S.D. G.M. AGM D.G.M. CM CM C.M. Engineer Dy. Mgr. D.G.M. G.M. Group Head Head Ele. Organisation WRPC WRPC WRPC WRPC WRPC WRPC SLDC, GETCO GETCO WRLDC WRLDC WRLDC POWERGRID WRLDC WRLDC WRLDC WRLDC NLDC TATA POWER CGPL CGPL E-mail [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] Mobile No. 9820878384 9223399938 8108787778 9867622823 9833371844 9869910968 9879200736 9978936145 9869438073 9869450221 9869088058 9428504065 9869404482 9869404673 9869414293 9869404569 8527077022 9099006541 7738373722 9227295358 List of participants for the Meeting held on 21 Mar 2014 at CGPL Mundra Sr. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Name Shri K K Sharma Shri S K Negi Shri S Baijal Shri Pancholi Shri SA Patel Shri P D Lone Shri Vivek Pandey Shri Anand Dubey Shri Soni Shri K N Athavale Shri R M Sankhe Shri K V Ghate Shri B M Shah Shri Alok Uppal Shri Jagmit Siddhu Shri Naveen Yadav Shri Sagnik Kundu Shri Sahoo Shri Avinash Kumar Shri Raman Bharmuria Shri Pryank Shah Designation ED & CEO M D Head‐O&M OSD EE EE Chief Manager Chief Manager Manager Head‐EMD Head‐Operations Head‐IMD EE Group Head‐ EMD Group Head‐ EMD Group Head‐ EMD Shift Charge Engineer Shift Charge Engineer Shift Charge Engineer Shift Charge Engineer Commercial Controller Organisation CGPL G ETCO CGPL GETCO G ETCO WRPC WRLDC PGClL PGClL CGPL CGPL CGPL GETCO CGPL CGPL CGPL CGPL CGPL CGPL CGPL CGPL ANNEXURE-II DETAILED ANALYSIS AND SEQUENCE OF EVENTS CO-RELATION SEQUENCE OF EVENTS Reports of the event along with DR/EL were forwarded by GETCO, POWERGRID and CGPL Mundra to WRLDC and WRPC. The DR/EL was discussed in the meetings and detailed analysis of the event was carried out based on the above reports and data from synchrophasors & SCADA and was discussed in the meetings. The Sequence of Events as inferred from the SOE in WRLDC SCADA and PMU data is as under: t = -11 min 13 sec 400 kV Chorania-CGPL-1 t = -11 min 13.993s 400 kV Chorania-Kosamba-1 t = 0ms 400 kV Chorania-Asoj t = 0ms 400 kV Chorania-Vadavi-2 t = 3ms 400 kV Chorania-CGPL-2 (both ends) {19:10:43.276} {19:21:57.273} {19:21:57.276} SPS-2 triggered for runback at CGPL units t = 32ms 400/220 kV ICT-2 at Chorania t = 80ms 400 kV Chorania-Amreli t = 721ms 400 kV Bachau-CGPL-2 (from Bachau end) t = 868ms 400 kV Bachau-CGPL-1 (from Bachau end) {19:21:58.141} SPS-1 triggered for tripping of 1 unit at CGPL (unit#40 was pre-selected) t = 1.315 sec 400 kV Jetpur-CGPL-1 (from Jetpur end) t = 1.315 sec 400 kV Jetpur-CGPL-2 (from Jetpur end) Loss of all Evacuating lines from CGPL. Station islanded and survived t = 1.385 sec 400 kV Bachau-Ranchodpura-1 Loss of power supply at 400 kV bus of Bachau as 220 kV lines to Lalpar and Morbi tripped while D/C to Halvad already under breakdown. t= 1.397 sec: 400 kV CGPL Mundra-Bachau 1 on O/V (from CGPL end) Annexure-II to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 1 t= 1.429 sec: 400 kV CGPL Mundra-Bachau-2 on Z1 distance (from CGPL end) t= 1.431 sec: 400 kV CGPL Mundra-Jetpur-2 on O/V (from CGPL end) t= 1.443 sec: 400 kV CGPL Mundra-Jetpur-1 on O/V (from CGPL end) t= 2.733 sec: Unit # 40 tripped (on SPS) t= 2.787 sec: Unit # 50 hand tripped t= 14.107 sec: Unit # 20 hand tripped t= 3 min, 46.430 sec: Unit # 30 hand tripped t= 6 min, 42.273sec: Unit # 10 tripped on exhaust hood temperature high CGPL power station Blackout t = 15 minutes Start up supply extended to 400 kV CGPL Mundra from 400 kV Jetpur Analysis of DR / EL reports and operation of protection systems : None of the DR/EL were seen to be time synchronized with GPS. However the inferences drawn from the reports are as under: a) Event 1: 400kV Chorania-Kosamba line No.1 : From Chorania end D.R it was observed that there was operation of reactor differential protection and line distance protection for 400kV Chorania-Kosamba line at Chorania end on failure of “B”phase reactor of the line. Both the protections sensed the fault correctly and tripped the breaker at Chorania end and also direct trip command was sent to Kosamba end. b) Event 1: 400kV Mundra-Chorania line-1 : From Chorania end D.R it was observed that there was operation of REF protection of reactor and fault current in neutral was 0.24 A. The operation of REF protection had tripped the breaker at Chorania end and also sent direct trip command to Mundra end. The operation of the REF protection at Chorania end on failure of NGR LA of the line reactor is in order. Reason for failure of NGR LA is being studied by PGCIL. c) Event 2: 400kV Chorania-Vadavi line-2, 400kV Chorania-Amreli line, 400kV ChoraniaMundra-2 line : Annexure-II to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 2 From D.R of Chorania end it was observed that the breakers of above lines tripped and the triggering event was bus bar protection relay. However no fault in system was observed through the disturbance record. d) 400kV Chorania S/S Bus-II LBB operation : The Master trip relay of 400kV ChoraniaKosamba line No. 1, was not resetted during the tripping of the line due to “B” phase line reactor failure. As per the DR of the event current of sufficient magnitude (>200mA) was seen flowing in the “B” phase of the Main-II relay. Therefore for operation of LBB of this line, both the conditions of stuck breaker protection i.e. Master trip operated and line current more than 200mA got satisfied and the relay operated correctly. Following elements connected to Bus-2 tripped 400/220kV, 500MVA ICT-2, 400kV Ranchodpura2, 400kV Asoj line No.2, 400kV, 50MVAR Bus reactor & 400kV Amreli. During the fire on the “B” phase of the line reactor of this line, it is suspected that the fire might have spread to control cables and the CT wiring of Main-I or the Bushing CT wires of the reactor and A.C. Auxiliary supply cables might have got damaged. Due to this the A.C supply might have leaked into the CT cables of either Main-II DPS or the reactor bushing CTs (used for line current compensation) and this leakage current of magnitude more than 200mA was extended to the Main-II DPS relay. The master trip relay after the earlier tripping of the line breaker was not resetted. This resulted in satisfying the conditions for stuck breaker condition and operation of LBB relay of this line. e) 400kV Mundra-Jetpur line-1 & 2 : From Jetpur end D.R it was observed that the lines tripped due to operation of DPS in Z1 and power swing detection from Jetpur end. The gradual fall of voltage and increase of current seen by the relay suggests that the power swing has entered in Z-1. f) 400kV Mundra-Bachau line-1&2 : From Bachau end D.R it was observed that breakers tripped due to operation of DPS in Z1 and power swing detection from Bachau end. The gradual fall of voltage and increase of current seen by the relay suggests that the power swing has entered in Z-1. g) 220kV Bhachau-Lalpar & Bhachau-Morbi lines: Annexure-II to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 3 Both these 220kV lines tripped in Z1 and power swing detection from Bhachau end. The gradual fall of voltage and increase of current seen by the relay suggests that the power swing has entered in Z-1. From the DRs of lines at e), f) & g), as above, it was observed that there was a gradual fall in voltage from 1 pu to around 0.40-0.50 pu and a gradual increase in current, clearly indicating a severe power swing between the CGPL generators and other generators in the grid. Further all these lines tripped on entering of power swing in Z1 of the respective lines from opposite end of CGPL. Therefore tripping of lines at e), f) & g), as above in Z-1 and power swing detection were in order. The offline simulation studies carried out by WRLDC for the above event also suggests that the power swing had entered in Z1 settings of DPS of the above lines. The DRs and the ELs are enclosed at Annexure-IV. Analysis of PMU data : The PMU plots are enclosed at Annexure-V a. The angular separation between CGPL bus with respect to Bhadrawati is seen to sharply increase from 17 degrees to 180 degrees followed by loss of synchronism. b. There was around 30 % voltage drop at CGPL Mundra within 1 sec 320 ms of loss of both circuits of CGPL Mundra-Chorania followed by sudden rise in voltage. Reactive power of CGPL generating units changed from -42 MVAR (lead) to 550 MVAR (lag) indicating fast AVR action c. Generation at CGPL Mundra is observed to reduce by around 100 MW after loss of both circuits of 400 kV CGPL Mundra-Chorania D/C d. The frequency of the 400 kV CGPL bus (islanded) touched 52.885 Hz after loss of synchronism with the grid within 2 seconds. The second peak of frequency occurring after 7.400 seconds was within 50.5 Hz, possibly due to fast governor action. Annexure-II to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 4 Annexure-III SPS for CGPL Bhachau-1 Bhachau-2 Or Or BhachauBhachauRanchodpura Ranchodpura Jetpur-1 & 2 line CGPL Gen 1 or 2 Line Loading in MW in MW Chorania-1 Chorania-2 1 or 2 Line Action at CGPL 1 >3100 X X >1500 2 >3100 X X >1500 3 >3100 4 5 6 7 X >3100 >3100 >3100 >3100 X X X X X >1500 X >1500 X >1500 >1500 >1200 X- indicates tripping of the line. Trip mills this will reduce generation by @500MW, except for condition 2 where unit would trip Alarm for reduction in generation so that the Jetpur lines loadings are maintained around 1200MW Annexure-IV 400KV CHORANIA / 400KV / 400KV KOSAMBA-1 87R 7UT612 V4.612-Mar-14 Var / 7:17:30 PM.779 t in ms Cursor 1: Measuring Signal Instantaneous 28.5 IDiff-L3 R.M.S. 221.66 mI/InO Trigger 12-Mar-14 7:17:30 PM.779 iL1-M1/ A 20 0 -20 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 t/s -40 iL2-M1/ A 20 0 -20 t/s -40 iL3-M1/ A 20 0 -20 t/s -40 3i0-M1/ A 20 0 -20 t/s -40 iL1-M2/ A 0 -10 t/s iL2-M2/ A 0.025 -0.000 -0.025 -0.050 t/s iL3-M2/ A 0.025 -0.000 -0.025 -0.050 15-Mar-14 / 7:56:25 AM SIGRA 4.51 t/s C:\USERS\ABC\DESKTOP\CHO. OCC. 12032014\400KV CHORANIA SS 12.3.14\BUS - 2\400KV KOSAMBA-1\87\550 400KV CHORANIA / 400KV / 400KV KOSAMBA-1 87R 7UT612 V4.612-Mar-14 Var / 7:17:30 PM.779 3i0-M2/ A 0 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 -10 t/s IDiff-L1/ I/InO 0.20 0.10 t/s 0.00 IDiff-L2/ I/InO 0.20 0.10 t/s 0.00 IDiff-L3/ I/InO 0.20 0.10 t/s 0.00 IRest-L1/ I/InO 0.20 0.10 t/s 0.00 IRest-L2/ I/InO 0.20 0.10 t/s 0.00 IRest-L3/ I/InO 0.20 0.10 t/s 0.00 Flag Lost >Trig.Wave.Cap. FltRecSta Relay TRIP Relay PICKUP Diff picked up Diff> TRIP Diff>> TRIP 64R FAULTY 15-Mar-14 / 7:56:25 AM SIGRA 4.51 t/s C:\USERS\ABC\DESKTOP\CHO. OCC. 12032014\400KV CHORANIA SS 12.3.14\BUS - 2\400KV KOSAMBA-1\87\550 400KV CHORANIA / 400KV / 400KV KOSAMBA-1 MAIN-2 DPS 7SA612 12-Mar-14 V4.7 Var / 7:19:31 PM.699 t in ms Cursor 1: Measuring Signal Instantaneous 0.0 iL3 R.M.S. 0.4931 kA 0.3798 kA Trigger 12-Mar-14 7:19:31 PM.699 iL1/ A 500 0 -500 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -1000 t/s iL2/ A 500 0 -500 -1000 t/s iL3/ A 500 0 -500 -1000 t/s iE/ A 500 0 -500 -1000 t/s uL1/ V 10000 0 -10000 -20000 t/s uL2/ V 10000 0 -10000 -20000 t/s uL3/ V 10000 0 -10000 -20000 t/s 15-Mar-14 / 7:31:01 AM C:\USERS\ABC\DESKTOP\CHO. OCC. 12032014\400KV CHORANIA SS 12.3.14\BUS - 2\400KV KOSAMBA-1\MAIN-2\1460 SIGRA 4.51 400KV CHORANIA / 400KV / 400KV KOSAMBA-1 MAIN-2 DPS 7SA612 12-Mar-14 V4.7 Var / 7:19:31 PM.699 uSYN2/ V 10000 0 -10000 -20000 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 t/s >Trig.Wave.Cap. Flag Lost SOF O/CtripL123 O/C PICKUP Power Swing Pow. Swing TRIP Dis.Pickup L1 Dis.Pickup L2 Dis.Pickup L3 Dis.Pickup E Dis. forward Dis. reverse Dis.Gen. Trip Dis.Trip 1pL1 Dis.Trip 1pL2 Dis.Trip 1pL3 Dis.Trip 3p Dis.TripZ1/1p Dis.TripZ1B1p Dis.TripZ2/1p Dis.TripZ2/3p Dis.TripZ3/T3 Dis.TRIP 3p. Z4 >CB1 Pole L1 >CB1 Pole L2 >CB1 Pole L3 >CB1 Ready Relay PICKUP Relay PICKUP L1 Relay PICKUP L2 Relay PICKUP L3 Relay PICKUP E t/s 15-Mar-14 / 7:31:01 AM C:\USERS\ABC\DESKTOP\CHO. OCC. 12032014\400KV CHORANIA SS 12.3.14\BUS - 2\400KV KOSAMBA-1\MAIN-2\1460 SIGRA 4.51 400KV CHORANIA / 400KV / 400KV KOSAMBA-1 MAIN-2 DPS 7SA612 12-Mar-14 V4.7 Var / 7:19:31 PM.699 Relay TRIP L1 Relay TRIP L2 Relay TRIP L3 Relay TRIP >Manual Close FltRecSta DisTRIP3p. Z1sf DisTRIP3p. Z1mf DisTRIP3p.Z1Bsf DisTRIP3p Z1Bmf AR CLOSE Cmd. AR Close1.Cyc1p BF T1-TRIP L123 AR Close1.Cyc3p Uph-e>(>) TRIP Uphph>(>) TRIP Line closure 1pole open L1 1pole open L2 1pole open L3 SF6 GAS LO M1 OPTD O/V M1 OPT COX CH2 COX CH1 CB L/O LBB&BBoptd 3PH TRIPop DTS CH-2 TC2unhealt DT RCV CH2 M2 OPTD -0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 t/s 15-Mar-14 / 7:31:01 AM C:\USERS\ABC\DESKTOP\CHO. OCC. 12032014\400KV CHORANIA SS 12.3.14\BUS - 2\400KV KOSAMBA-1\MAIN-2\1460 SIGRA 4.51 Limbdi 120314 SIGRA 4.4 Mundra 2 7SA522 V4.6 Var 7:21:56 PM.040 Trigger 3/12/2014 7:21:56 PM.040 iL1/kA 1.0 0.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 t/s 0.0 iL2/kA 1.0 0.5 t/s 0.0 iL3/kA 1.0 0.5 t/s 0.0 uL1/kV 200 100 t/s 0 uL2/kV 200 100 t/s 0 uL3/kV 200 100 0 - 2 - t/s Limbdi 120314 SIGRA 4.4 Mundra 2 7SA522 V4.6 Var 7:21:56 PM.040 L CB R opn L CB Y opn L CB B opn M1carr rec M1 Trip A/R oprtd OV stg1&2 STUB oprtd DT recev M2 optd BB oprtd LBB oprtd TBC R opn TBC Y opn TBC B opn A/R unscs Diff optd REF optd BUimpd opt M2carr rec Z1 trip Z1B trip Z2 trip Z3 trip Z5 trip SOTF trip Power swn E/F trip 0.5 1.0 1.5 2.0 - 3 - 2.5 3.0 3.5 4.0 4.5 t/s Bhachau 400-220 13072013 / 400kV SIGRA 4.4 BAY 407 Ranchodpura L 1 B407 21 7:21:56 PM.449 Trigger 3/12/2014 7:21:56 PM.449 iL1/kA 2 1 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 t/s 0 iL2/kA 3 2 1 t/s 0 iL3/kA 2 1 t/s 0 uL1/kV 200 100 t/s 0 uL2/kV 200 100 t/s 0 uL3/kV 200 100 t/s 0 iEp/A 75 50 25 0 - 2 - t/s SIGRA 4.4 Bhachau 400-220 13072013 / 400kV BAY 407 Ranchodpura L 1 B407 21 7:21:56 PM.449 DT Send M Rph Open M Yph Open M Bph Open M1 CR M1 Trip A/R Optd O/V Optd STUB trip DT recieve M2 Trip BB Trip LBB optd TieRph Opn TieYph Opn TieBph Opn Z1B Trip Z1 strt Z2 Strt Z3 Strt Z4 Strt Z5 Strt SOTF Trip Z1 trip Z2 trip Z3 trip Z4 trip Z5 trip PSD M A/R Blk T A/R Blk DT Send 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 t/s M A/R Unsu T A/R Unsu 86A Trip 86B Trip DEF Trip Car Out TieLBBOptd M2 CR - 3 - t/s Limbdi 120314 SIGRA 4.4 Vadavi 2 7SA522 V4.6 Var 7:21:55 PM.740 Trigger 3/12/2014 7:21:55 PM.740 K1:iL1/A 200 100 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 t/s 0 K1:iL2/A 200 100 t/s 0 K1:iL3/A 200 100 t/s 0 K1:uL1/kV 100 t/s 0 K1:uL2/kV 100 t/s 0 K1:uL3/kV 100 t/s 0 K2:iEp/A 200 100 0 - 2 - t/s Limbdi 120314 SIGRA 4.4 Vadavi 2 7SA522 V4.6 Var 7:21:55 PM.740 M CB R opn M CB Y opn M CB B opn M1 Car Rec M1 trip A/R op O/V optd Teed Op DT rec M2 carr re M2DistOpt B.B trip M/T LBB op TBC R opn TBC Y opn TBC B opn 0.25 0.50 0.75 1.00 - 3 - 1.25 1.50 1.75 t/s Bhachau 400-220 13072013 / 400kV SIGRA 4.4 BAY 404 Mundra Line 1 B404 21 7:21:56 PM.765 Trigger 3/12/2014 7:21:56 PM.765 K1:iL1/kA 3 2 1 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 t/s 0 K1:iL2/kA 3 2 1 t/s 0 K1:iL3/kA 3 2 1 t/s 0 K1:uL1/kV 300 200 100 t/s 0 K1:uL2/kV 300 200 100 t/s 0 K1:uL3/kV 300 200 100 t/s 0 K2:iEp/kA 3 2 1 0 - 2 - t/s SIGRA 4.4 Bhachau 400-220 13072013 / 400kV BAY 404 Mundra Line 1 B404 21 7:21:56 PM.765 M Rph Open M Yph Open M Bph Open M1 CR M1 Trip A/R Optd O/V Optd STUB trip DT recieve M2 Trip BB Trip LBB optd TieRph Opn TieYph Opn TieBph Opn Z1B Trip Z1 strt Z2 Strt Z3 Strt Z4 Strt Z5 Strt SOTF Trip Fuse Fail Z1 trip Z2 trip Z3 trip Z4 trip Z5 trip PSD M A/R Blk T A/R Blk DT Send 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 t/s M A/R Unsu T A/R Unsu 86A Trip 86B Trip DEF Trip Car Out TieLBBOprd M2 CR - 3 - t/s JETPUR S/S SIGRA 4.4 7:21:04 PM.833 Trigger 3/12/2014 7:21:05 PM.334 LINE_A_IL1/kA 1.5 1.0 0.5 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 t/s 0.0 LINE_A_IL2/kA 1.5 1.0 0.5 t/s 0.0 LINE_A_IL3/kA 1.5 1.0 0.5 t/s 0.0 LINE_A_IN/kA 1.5 1.0 0.5 t/s 0.0 LINE_UL1/kV 200 100 t/s 0 LINE_UL2/kV 200 100 t/s 0 LINE_UL3/kV 200 100 0 - 6 - t/s JETPUR S/S SIGRA 4.4 7:21:04 PM.833 MAIN CB R OPN MAIN CB Y OPN MAIN CB B OPN M2 CARR RECVD AR_CLOSE TOV1-TRIP TBC CB R OPEN TBC CB Y OPEN TBC CB B OPEN ZM01-TRIP ZM02-TRIP ZM03-TRIP ZM04-TRIP SOTF-TRIP ZCOM-TRIP DT_SEND PHS-STFWL1 PHS-STFWL2 PHS-STFWL3 PHS-STFWPE PSB-OPTD VTS TOV1-TRIP TOV2-TRIP TOV START-1/2 CARRIER_REC MAIN CB R OPN MAIN CB Y OPN MAIN CB B OPN SOTF INI TBC CB R OPEN TBC CB Y OPEN 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 t/s TBC CB B OPEN REACTR TROUBE M2 CARR RECVD TR_R_MAIN_CB TR_Y_MAIN_CB TR_B_MAIN_CB CARR_SEND TR_R_TBC_CB TR_Y_TBC_CB TR_B_TBC_CB TRIP_3P_MAIN TRIP_3P_TBC - 7 - t/s Limbdi 120314 SIGRA 4.4 Mundra 1 7SA522 V4.6 Var 7:10:41 PM.692 Trigger 3/12/2014 7:10:41 PM.692 K1:iL1/kA 1.5 1.0 0.5 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 0.25 0.50 0.75 1.00 1.25 1.50 1.75 t/s 0.0 K1:iL2/kA 1.5 1.0 0.5 t/s 0.0 K1:iL3/kA 1.5 1.0 0.5 t/s 0.0 K1:uL1/kV 200 100 t/s 0 K1:uL2/kV 200 100 t/s 0 K1:uL3/kV 200 100 t/s 0 K2:iEp/kA 1.5 1.0 0.5 0.0 - 2 - t/s Limbdi 120314 SIGRA 4.4 Mundra 1 7SA522 V4.6 Var 7:10:41 PM.692 L CB R opn L CB Y opn L CB B opn M1carr rec M1 Trip A/R oprtd OV stg1&2 STUB oprtd DT recev M2 optd BB oprtd LBB oprtd TBC R opn TBC Y opn TBC B opn A/R unscs Diff optd REF optd BUimpd opt M2carr rec Z1 trip Z1B trip Z2 trip Z3 trip Z5 trip SOTF trip Power swn E/F trip 0.25 0.50 0.75 1.00 - 3 - 1.25 1.50 1.75 t/s Annexure-V PMU Plots Annexure-V to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 1 Annexure-V to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 2
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