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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

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12) S.E. (Testing), GETCO, Baroda. Fax-0265-2351218

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22) SE, Electricity Dept., DNH, Silvasa. Fax : 0260-2642338

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24) D.G.M. (O.S. ),N.T.P.C., Mumbai, Fax- 28216692

25) DGM, NTPC WR – II, Raipur, Fax: 0771 - 2544550

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31) DGM (O.S.), WRLDC, Mumbai Fax-28235434

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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

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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. Page 1

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 WESTERN REGION PARTICULARS

Region 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 625

ALL INDIA 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 : 1110 MW (555 MW /ckt)

400 kV Mundra – Chorania (Limbdi) D/C : 1510 MW (755 MW /ckt)

400 kV Mundra- Jetpur D/C : 1144 MW (572 MW/ckt)

400 kV Kosamba-Chorania-1 line was under construction and kept in charged from Chorania end.


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 CGPL-

Bachau 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


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°.


(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 Indore-

Asoj.


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.


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


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


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.


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.

**************

Sl.No. Name Designation Organisation E-mail Mobile No. 1 Shri S.D. Taksande M.S. WRPC [email protected] 98208783842 Shri Satyanarayan S. S E (Comml.) WRPC [email protected] 92233999383 Shri M.M. Dhakate S.E.(Opn.) WRPC [email protected] 81087877784 Shri P.D. Lone E E (Comml.) WRPC [email protected] 98676228235 Shri L.K.S. Rathore EE(Opn.) WRPC [email protected] 98333718446 Shri Shiva Suman A D (Comml.) WRPC [email protected] 98699109687 Shri B.B. Mehta C. E. SLDC, GETCO [email protected] 98792007368 Shri J.N. Pancholi O.S.D. GETCO [email protected] 99789361459 Shri P. Mukhopadhyay G.M. WRLDC [email protected] 986943807310 Shri V.K. Shrivastav A G M WRLDC [email protected] 986945022111 Shri Abhimanyu Gartia D.G.M. WRLDC [email protected] 986908805812 Shri Anand Dubey CM POWERGRID [email protected] 942850406513 Smt. Pushpa S. C M WRLDC [email protected] 986940448214 Shri Vivek Pandey C.M. WRLDC [email protected] 986940467315 Shri Awani Rai Engineer WRLDC [email protected] 986941429316 Shri Aditya P.Das Dy. Mgr. WRLDC [email protected] 986940456917 Shri N. Nallarasan D.G.M. NLDC [email protected] 852707702218 Shri R.M. Sankhe G.M. TATA POWER [email protected] 909900654119 Shri Vipul Raval Group Head CGPL [email protected] 773837372220 Shri K.N. Athavale Head Ele. CGPL [email protected] 9227295358

Participants list for Special meeting (CGPL) held on19.03.14 at WRLDC, Mumbai

Annexure-I

Sr. No. Name Designation Organisation1 Shri K K Sharma ED & CEO CGPL2 Shri S K Negi M D G ETCO3 Shri S Baijal Head‐O&M CGPL4 Shri Pancholi OSD GETCO5 Shri SA Patel EE G ETCO6 Shri P D Lone EE WRPC7 Shri Vivek Pandey Chief Manager WRLDC8 Shri Anand Dubey Chief Manager PGClL9 Shri Soni Manager PGClL10 Shri K N Athavale Head‐EMD CGPL11 Shri R M Sankhe Head‐Operations CGPL12 Shri K V Ghate Head‐IMD CGPL13 Shri B M Shah EE GETCO14 Shri Alok Uppal Group Head‐ EMD CGPL15 Shri Jagmit Siddhu Group Head‐ EMD CGPL16 Shri Naveen Yadav Group Head‐ EMD CGPL17 Shri Sagnik Kundu Shift Charge Engineer CGPL18 Shri Sahoo Shift Charge Engineer CGPL19 Shri Avinash Kumar Shift Charge Engineer CGPL20 Shri Raman Bharmuria Shift Charge Engineer CGPL21 Shri Pryank Shah Commercial Controller CGPL

List of participants for the Meeting held on 21 Mar 2014 at CGPL Mundra

Annexure-II to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 1

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 {19:10:43.276}

t = -11 min 13.993s 400 kV Chorania-Kosamba-1

t = 0ms 400 kV Chorania-Asoj {19:21:57.273}

t = 0ms 400 kV Chorania-Vadavi-2

t = 3ms 400 kV Chorania-CGPL-2 (both ends) {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)


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 Chorania-

Mundra-2 line :


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 Chorania-

Kosamba 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 Ranchodpura-

2, 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:


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-III

SPS for CGPL

CGPL Gen in MW Chorania-1 Chorania-2

Bhachau-1 Or

Bhachau- Ranchodpura

1 or 2 Line

Bhachau-2 Or

Bhachau- Ranchodpura

1 or 2 Line Jetpur-1 & 2 line Loading in MW Action at CGPL

1

>3100 X X

>1500

Trip mills this will reduce generation by @500MW, except for condition 2 where unit would

trip

2 >3100

X X >1500

3 >3100 X

X

>1500

4 >3100

X

X >1500

5 >3100 X

X >1500

6 >3100

X X

>1500

7 >3100

>1200 Alarm for reduction in generation so that the Jetpur lines loadings are

maintained around 1200MW

X- indicates tripping of the line.

400KV CHORANIA / 400KV / 400KV KOSAMBA-1 87R 7UT612 V4.6 Var12-Mar-14 / 7:17:30 PM.779

15-Mar-14 / 7:56:25 AM

SIGRA 4.51

C:\USERS\ABC\DESKTOP\CHO. OCC. 12032014\400KV CHORANIA SS 12.3.14\BUS - 2\400KV KOSAMBA-1\87\550

t in ms Measuring Signal Instantaneous R.M.S.

Cursor 1: 28.5 IDiff-L3 221.66 mI/InO

Trigger12-Mar-14

7:17:30 PM.779

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

iL1-M1/ A

-40

-20

0

20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

iL2-M1/ A

-40

-20

0

20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

iL3-M1/ A

-40

-20

0

20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

3i0-M1/ A

-40

-20

0

20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

iL1-M2/ A

-10

0

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

iL2-M2/ A

-0.050

-0.025

-0.000

0.025

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

iL3-M2/ A

-0.050

-0.025

-0.000

0.025

400KV CHORANIA / 400KV / 400KV KOSAMBA-1 87R 7UT612 V4.6 Var12-Mar-14 / 7:17:30 PM.779

15-Mar-14 / 7:56:25 AM

SIGRA 4.51

C:\USERS\ABC\DESKTOP\CHO. OCC. 12032014\400KV CHORANIA SS 12.3.14\BUS - 2\400KV KOSAMBA-1\87\550

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

3i0-M2/ A

-10

0

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

IDiff-L1/ I/InO

0.00

0.10

0.20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

IDiff-L2/ I/InO

0.00

0.10

0.20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

IDiff-L3/ I/InO

0.00

0.10

0.20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

IRest-L1/ I/InO

0.00

0.10

0.20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

IRest-L2/ I/InO

0.00

0.10

0.20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

IRest-L3/ I/InO

0.00

0.10

0.20

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2

64R FAULTYDiff>> TRIP

Diff> TRIPDiff picked up

Relay PICKUPRelay TRIP

FltRecSta>Trig.Wave.Cap.

Flag Lost

400KV CHORANIA / 400KV / 400KV KOSAMBA-1 MAIN-2 DPS 7SA612 V4.7 Var12-Mar-14 / 7:19:31 PM.699

15-Mar-14 / 7:31:01 AM

SIGRA 4.51

C:\USERS\ABC\DESKTOP\CHO. OCC. 12032014\400KV CHORANIA SS 12.3.14\BUS - 2\400KV KOSAMBA-1\MAIN-2\1460

t in ms Measuring Signal Instantaneous R.M.S.

Cursor 1: 0.0 iL3 0.4931 kA 0.3798 kA

Trigger12-Mar-14

7:19:31 PM.699

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

iL1/ A

-1000

-500

0

500

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

iL2/ A

-1000

-500

0

500

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

iL3/ A

-1000

-500

0

500

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

iE/ A

-1000

-500

0

500

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

uL1/ V

-20000

-10000

0

10000

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

uL2/ V

-20000

-10000

0

10000

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

uL3/ V

-20000

-10000

0

10000


15-Mar-14 / 7:31:01 AM

SIGRA 4.51


t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

uSYN2/ V

-20000

-10000

0

10000

t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

Relay PICKUP ERelay PICKUP L3Relay PICKUP L2Relay PICKUP L1

Relay PICKUP>CB1 Ready

>CB1 Pole L3>CB1 Pole L2>CB1 Pole L1

Dis.TRIP 3p. Z4Dis.TripZ3/T3Dis.TripZ2/3pDis.TripZ2/1p

Dis.TripZ1B1pDis.TripZ1/1p

Dis.Trip 3pDis.Trip 1pL3Dis.Trip 1pL2Dis.Trip 1pL1Dis.Gen. Trip

Dis. reverseDis. forward

Dis.Pickup EDis.Pickup L3Dis.Pickup L2Dis.Pickup L1

Pow. Swing TRIPPower SwingO/C PICKUP

SOF O/CtripL123Flag Lost

>Trig.Wave.Cap.


15-Mar-14 / 7:31:01 AM

SIGRA 4.51


t/s-0.4 -0.2 -0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

M2 OPTDDT RCV CH2

TC2unhealtDTS CH-2

3PH TRIPopLBB&BBoptd

CB L/OCOX CH1COX CH2

O/V M1 OPTM1 OPTD

SF6 GAS LO1pole open L31pole open L21pole open L1

Line closureUphph>(>) TRIPUph-e>(>) TRIP

AR Close1.Cyc3pBF T1-TRIP L123AR Close1.Cyc1pAR CLOSE Cmd.

DisTRIP3p Z1BmfDisTRIP3p.Z1BsfDisTRIP3p. Z1mfDisTRIP3p. Z1sf

FltRecSta>Manual Close

Relay TRIPRelay TRIP L3Relay TRIP L2Relay TRIP L1

SIGRA 4.4 Limbdi 120314 Mundra 2 7SA522 V4.6 Var 7:21:56 PM.040

- 2 -

Trigger3/12/2014

7:21:56 PM.040

t/s0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

iL1/kA

0.0

0.5

1.0

t/s0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

iL2/kA

0.0

0.5

1.0

t/s0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

iL3/kA

0.0

0.5

1.0

t/s0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

uL1/kV

0

100

200

t/s0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

uL2/kV

0

100

200

t/s0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

uL3/kV

0

100

200


- 3 -

t/s0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

E/F tripPower swnSOTF trip

Z5 tripZ3 tripZ2 trip

Z1B tripZ1 trip

M2carr recBUimpd opt

REF optdDiff optd

A/R unscsTBC B opnTBC Y opnTBC R opnLBB oprtd

BB oprtdM2 optd

DT recevSTUB oprtdOV stg1&2

A/R oprtdM1 Trip

M1carr recL CB B opnL CB Y opnL CB R opn

SIGRA 4.4 Bhachau 400-220 13072013 / 400kV BAY 407 Ranchodpura L 1 B407 21 7:21:56 PM.449

- 2 -

Trigger3/12/2014

7:21:56 PM.449

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

iL1/kA

0

1

2

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

iL2/kA

0

1

2

3

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

iL3/kA

0

1

2

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

uL1/kV

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

uL2/kV

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

uL3/kV

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

iEp/A

0

25

50

75

SIGRA 4.4 Bhachau 400-220 13072013 / 400kV BAY 407 Ranchodpura L 1 B407 21 7:21:56 PM.449

- 3 -

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

DT SendT A/R BlkM A/R Blk

PSDZ5 tripZ4 tripZ3 tripZ2 tripZ1 trip

SOTF TripZ5 StrtZ4 StrtZ3 StrtZ2 StrtZ1 strt

Z1B TripTieBph OpnTieYph OpnTieRph Opn

LBB optdBB TripM2 Trip

DT recieveSTUB tripO/V OptdA/R Optd

M1 TripM1 CR

M Bph OpenM Yph OpenM Rph Open

DT Send

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

M2 CRTieLBBOptd

Car OutDEF Trip86B Trip86A Trip

T A/R UnsuM A/R Unsu

SIGRA 4.4 Limbdi 120314 Vadavi 2 7SA522 V4.6 Var 7:21:55 PM.740

- 2 -

Trigger3/12/2014

7:21:55 PM.740

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:iL1/A

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:iL2/A

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:iL3/A

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:uL1/kV

0

100

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:uL2/kV

0

100

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:uL3/kV

0

100

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K2:iEp/A

0

100

200

SIGRA 4.4 Limbdi 120314 Vadavi 2 7SA522 V4.6 Var 7:21:55 PM.740

- 3 -

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

TBC B opnTBC Y opnTBC R opn

M/T LBB opB.B trip

M2DistOptM2 carr re

DT recTeed OpO/V optd

A/R opM1 trip

M1 Car RecM CB B opnM CB Y opnM CB R opn

SIGRA 4.4 Bhachau 400-220 13072013 / 400kV BAY 404 Mundra Line 1 B404 21 7:21:56 PM.765

- 2 -

Trigger3/12/2014

7:21:56 PM.765

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

K1:iL1/kA

0

1

2

3

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

K1:iL2/kA

0

1

2

3

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

K1:iL3/kA

0

1

2

3

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

K1:uL1/kV

0

100

200

300

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

K1:uL2/kV

0

100

200

300

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

K1:uL3/kV

0

100

200

300

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

K2:iEp/kA

0

1

2

3

SIGRA 4.4 Bhachau 400-220 13072013 / 400kV BAY 404 Mundra Line 1 B404 21 7:21:56 PM.765

- 3 -

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

DT SendT A/R BlkM A/R Blk

PSDZ5 tripZ4 tripZ3 tripZ2 tripZ1 trip

Fuse FailSOTF Trip

Z5 StrtZ4 StrtZ3 StrtZ2 StrtZ1 strt

Z1B TripTieBph OpnTieYph OpnTieRph Opn

LBB optdBB TripM2 Trip

DT recieveSTUB tripO/V OptdA/R Optd

M1 TripM1 CR

M Bph OpenM Yph OpenM Rph Open

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75

M2 CRTieLBBOprd

Car OutDEF Trip86B Trip86A Trip

T A/R UnsuM A/R Unsu

SIGRA 4.4 JETPUR S/S 7:21:04 PM.833

- 6 -

Trigger3/12/2014

7:21:05 PM.334

t/s0.0 0.5 1.0 1.5 2.0 2.5

LINE_A_IL1/kA

0.0

0.5

1.0

1.5

t/s0.0 0.5 1.0 1.5 2.0 2.5

LINE_A_IL2/kA

0.0

0.5

1.0

1.5

t/s0.0 0.5 1.0 1.5 2.0 2.5

LINE_A_IL3/kA

0.0

0.5

1.0

1.5

t/s0.0 0.5 1.0 1.5 2.0 2.5

LINE_A_IN/kA

0.0

0.5

1.0

1.5

t/s0.0 0.5 1.0 1.5 2.0 2.5

LINE_UL1/kV

0

100

200

t/s0.0 0.5 1.0 1.5 2.0 2.5

LINE_UL2/kV

0

100

200

t/s0.0 0.5 1.0 1.5 2.0 2.5

LINE_UL3/kV

0

100

200

SIGRA 4.4 JETPUR S/S 7:21:04 PM.833

- 7 -

t/s0.0 0.5 1.0 1.5 2.0 2.5

TBC CB Y OPENTBC CB R OPEN

SOTF INIMAIN CB B OPNMAIN CB Y OPNMAIN CB R OPNCARRIER_RECTOV START-1/2

TOV2-TRIPTOV1-TRIP

VTSPSB-OPTD

PHS-STFWPEPHS-STFWL3PHS-STFWL2PHS-STFWL1

DT_SENDZCOM-TRIPSOTF-TRIPZM04-TRIPZM03-TRIPZM02-TRIPZM01-TRIP

TBC CB B OPENTBC CB Y OPENTBC CB R OPEN

TOV1-TRIPAR_CLOSE

M2 CARR RECVDMAIN CB B OPNMAIN CB Y OPNMAIN CB R OPN

t/s0.0 0.5 1.0 1.5 2.0 2.5

TRIP_3P_TBCTRIP_3P_MAINTR_B_TBC_CBTR_Y_TBC_CBTR_R_TBC_CB

CARR_SENDTR_B_MAIN_CBTR_Y_MAIN_CBTR_R_MAIN_CB

M2 CARR RECVDREACTR TROUBE

TBC CB B OPEN


- 2 -

Trigger3/12/2014

7:10:41 PM.692

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:iL1/kA

0.0

0.5

1.0

1.5

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:iL2/kA

0.0

0.5

1.0

1.5

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:iL3/kA

0.0

0.5

1.0

1.5

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:uL1/kV

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:uL2/kV

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K1:uL3/kV

0

100

200

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

K2:iEp/kA

0.0

0.5

1.0

1.5


- 3 -

t/s0.25 0.50 0.75 1.00 1.25 1.50 1.75

E/F tripPower swnSOTF trip

Z5 tripZ3 tripZ2 trip

Z1B tripZ1 trip

M2carr recBUimpd opt

REF optdDiff optd

A/R unscsTBC B opnTBC Y opnTBC R opnLBB oprtd

BB oprtdM2 optd

DT recevSTUB oprtdOV stg1&2

A/R oprtdM1 Trip

M1carr recL CB B opnL CB Y opnL CB R opn

Annexure-V to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 1

Annexure-V

PMU Plots

Annexure-V to the Report on Blackout at CGPL Mundra (UMPP) at 19:22 hrs, 12-March-2014. Page 2

pcm’s mailing list - wrpcwrpc.gov.in/pcm/cgpl_report.pdf · report on blackout at cgpl mundra...

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