Minutes of

59th PCC meeting

Date: 22.09.2017 Eastern Regional Power Committee

14, Golf Club Road, Tollygunge Kolkata: 700 033

EASTERN REGIONAL POWER COMMITTEE

MINUTES OF 59TH PROTECTION SUB-COMMITTEE MEETING HELD AT ERPC,

KOLKATA ON 20.09.2017 (WEDNESDAY) AT 11:00 HOURS

List of participants is enclosed at Annexure-A.

PART – A

ITEM NO. A.1: Confirmation of minutes of 58th Protection sub-Committee Meeting held on 29th August, 2017 at ERPC, Kolkata.

The minutes of 58th Protection Sub-Committee meeting held on 29.08.17 circulated vide letter dated 11.09.17. Members may confirm the minutes of 58th PCC meeting. Deliberation in the meeting Members confirmed the minutes of 58th PCC meeting.

PART – B

ANALYSIS & DISCUSSION ON GRID INCIDENCES OCCURRED IN AUGUST, 2017 ITEM NO. B.1: Disturbance at 220 kV CTPS B S/s on 28-08-17 at 13:25 hrs Due to bursting of R phase CT of U # VIII GT at CTPS B, bus differential relay at 220kV CTPS B operated and tripped the following elements connected to Bus-I:

220 KV CTPS B-CTPS A-I, 220 KV CTPS B- Dhanbad-II, 220 KV CTPS B-Bokaro B-I CTPS B unit # 8.

Unit # 7 Tripped due to loss of all fuel. HT Board 7CA tripped at the time of disturbance through Board U/V relay. Consequently, 400/220 kV ICT at Bokaro A loading became more than 299 MW. After opening of 220 kV Bokaro B - Jamshedpur D/C and 220 kV Dhanbad - Giridih D/C at 13:30 hrs, ICT loading got reduced to 255 MW. Further at 15:15 hrs, 132 kV Bokaro - Konar S/C and 132 kV Bokaro - Bari S/C were opened to reduce 400/220 kV ICT loading. DVC may explain. Deliberation in the meeting DVC explained that bus differential relay at 220kV CTPS B was operated due to bursting of R phase CT of U # VIII GT and tripped all the elements connected to Bus-I. PCC felt that the tripping was in order except Unit # 7 Tripping on loss of fuel. PCC advised DVC to investigate the Unit # 7 Tripping and submit the details to ERPC and ERLDC.

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ITEM NO. B.2: Disturbance at 220/132 kV Waria S/s on 27-08-17 at 07:36 hrs Due to massive fire hazard at 132/33/3.3 kV station transformer # III at Waria, all 220 kV and 132 kV feeders are hand tripped resulting in total power failure at surrounding area. Analysis:

1. Although the ST # 3 at Waria Differential relay operated, the breaker did not open. This caused tripping of all lines from remote end and all ATRs through LV O/C relay to isolate the fault.

2. DTPS Jamuria Line should have tripped from Jamuria end through Zone 2. But it did not trip. Instead Jamuria CTPS Line tripped from CTPS end through Distance Zone 3. DR of DTPS Jamuria Line at Jamuria Line showed that the fault had moved out of Zone 2 boundary before Z2 trip time.

3. This was because the fault resistance had varied during the fault. As Jamuria DTPS line has SEL 311C relay with MHO characteristics the high impedance fault was undetected by this relay. Instead the relay of next section saw the fault within Z3 and tripped earlier as it had Quad Characteristics.

Relay indications:

In Durgapur PMU data, delayed clearance (700 ms) of Y-B phase fault (15 kV voltage dip) has been observed at 07:35 hrs. DVC may explain. Deliberation in the meeting DVC explained that there was a massive fire hazard at 132/33/3.3 kV station transformer # III at Waria due to insulation failure. The transformer differential protection has operated but the breaker failed to open. Since the LBB protection of 132KV Waria S/s is not in service, the fault was isolated from ATRs through LV O/C relay and remote end of the transmission line.

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DVC added that all 132kV lines tripped from remote end on zone 2 except 132kV Waria-Jamuria line. DR of Jamuria end showed that the fault had moved out of Zone 2 boundary before zone 2 trip time because of high fault resistance. SEL 311C relay with MHO characteristics is available at Jamuria end of 132kV Waria-Jamuria line and the relay failed to detect the high resistance fault. The fault got cleared after tripping of the adjacent line (132kV Jamuria-CTPS Line) from CTPS end on Zone 3. The zone 3 time setting is 600 ms. PCC advised DVC to operationalize the LBB protection at 132kV Waria S/s.

BURDWAN KALIPAHARI

ASP

L#76

L#75

L#20

L#

21

L#51

L#52

ST#3

Z#2 Z#2 Z#2 Z#2

Z#2Z#2

Ramkanali

L#10

0L#

60

CTPS

DTPS 132KV

Jamuria

L#61

L#90

Z#2

Z#3

No trip

ITEM NO. B.3: Disturbance at 220 kV Bakreswar S/s on 11-08-17 at 16:05 hrs At 16:05 hrs all elements connected to Bakreswar 220 kV bus - I along with unit #III & #IV tripped due to operation of bus bar protection (96A) and Bus bar differential (87C, Check zone). At the same time R-N fault has been reported at 0.5 km from Bakreswar in 220 kV Bakreswar - Sadaipur - II. In PMU data, no fault has been captured at 16:05 hrs. However a 23 kV voltage dip in R phase has been observed at 16:01 hrs, which was cleared within 80 ms. 220kV Bus configuration at 220kV Bakreswar: BUS A: 1) 220 kV BkTPP-Sadaipur Ckt # 2, 2) 220 kV BkTPP- Satgachia Ckt # 1, 3) 220 kV BkTPP-Bidhannagar Ckt # 1, 4) 220 kV side Tie Trf. # 2, 5) GT # 3, 6) GT # 4, 7) ST # 4, 8) New PASS bay. BUS B: 1) 220 kV BkTPP-Sadaipur Ckt # 1, 2) 220 kV BkTPP- Satgachia Ckt # 2, 3) 220 kV BkTPP-Bidhannagar Ckt # 2, 4) 220 kV side Tie Trf. # 1, 5) GT # 5, 6) ST # 5, 7) ST#3

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WBPDCL may explain. Deliberation in the meeting WBPDCL explained that there was a R-N fault in 220 kV Bakreswar - Sadaipur – II near to Bakreswar due to severe lightening strike. The bus bar protection of 220kV Bus-I at Bakreswar operated and tripped all the elements connected to Bus-I. WBPDCL added that old EM type bus bar protection is available at 220kV Bakreswar and they are suspecting that the bus bar protection operated due to CT saturation. PCC advised WBPDCL to check the respective CT core of 220 kV Bakreswar - Sadaipur – II at Bakreswar for saturation and also to replace the old EM type bus bar protection with numerical relay. WBPDCL informed they have already applied for PSDF to upgrade the bus bar protection. ITEM NO. B.4: Disturbance at 400/220 kV Sasaram S/s on 12-08-17 at 14:51 hrs While availing emergency s/d of 220 kV bus I (East side) at Sasaram, HVDC Sasaram B/B, along with 765/400 kV 1500 MVA ICT - I and 400/220 kV ICT - I & II tripped resulting tripping of all 220 kV feeders eliminating from Sasaram followed by total supply of failure at 220 kV switchyard at Sasaram. While transferring all elements to 220 KV Bus II from 220 kV bus I, flashover occurred in 220 kV Bus - I side isolator of 400/220 kV ICT-II. At the time of opening of Bus Coupler, connection of different fdrs to BUS-1 & 2 was as follows: Bus-1 1. 315 MVA ICT-2 2. Shahupuri fdr 3. Ara fdr Bus-2 1. 500 MVA ICT-1 2. Nadokhar fdr 3. Dehri fdr Fault clearing time as per PMU data: 1700 ms

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Analysis: After closing of Isolator 389A, 500MVA ICT-I also get connection with Bus-1, which was initially feeded only bus-2 and hence flow of power may have increased in the isolator 389B for supplying of power to Shahupuri and Ara. Due to the mentioned reasons flashing started appearing in R & B contact of the mentioned isolator 389A of ICT-2 bay. It grow very rapidly and flame/ flash was observed between corona disc of male and female contacts.. When Main Bus-1 isolator of ICT-1 was only path for supplying power of ICT-1 &2 to Shaupuri and Ara. Due to high resistance hot spot occurred which further developed into flames causing melting of corona discs. This has resulted into tripping of ICT-1 on Over current protection. Pitting of conductor between 220 KV LA of ICT-1 and suspension insulator from the gantry has also been observed. This may be due to flashover between conductor and gantry. This may be the reason of differential protection of ICT-2. Powergrid may explain. Deliberation in the meeting Powergrid explained the disturbance with detailed presentation. Presentation is enclosed at Annexure-B4. Powergrid explained that

Flashover occurred at 220 kV Bus - I side isolator of 400/220 kV ICT-II, while transferring 220 KV Bus II elements to 220 kV bus I.

During closing of Main Bus-2 isolator 389B, the main bus-1 isolator 389 A may have experienced jerk due to mechanically coupling with IPS tube, resulting into losing of isolator female contact spring tip.

After closing of Isolator 389B, 400/220 kV, 500MVA ICT-I also get connected with Bus-1, which was initially feeding only through bus-2 and hence flow of current might have increased in the isolator 389A for supplying of power to Shahupuri and Ara

Flashover grew very rapidly and flame was observed between corona disc of male and female contacts

400/220 kV , ICT-2 tripped on B-ph differential protection and 400/220 kV, ICT-1 tripped on B-Ph over current protection. 220kV bus became dead.

765/400 kV 1500 MVA ICT – I also tripped on neutral over current protection BSPTCL informed that 220kV Sasaram-Dehri line tripped from Dehri end on zone 2. Powergrid added that damaged isolator arms and contacts have replaced. PCC felt that tripping of 765/400 kV 1500 MVA ICT – I on neutral over current protection is not justified. PCC advised Powergrid to investigate the tripping and submit the details to ERPC and ERLDC. ITEM NO. B.5: Disturbance at 220 kV Purnea and Madhepura S/s on 14-08-17 at 08:55 hrs 220/132/33 KV Madhepura GSS was availing power from 220/132 KV Purnea(PG). There was a transient fault(Y,B fault) at 8:55 hrs at distance 77.5 Km from GSS Madhepura in Circuit 1 of 220 KV Purnea(PG)-Madhepura D/C. Due to this fault, Circuit 1 tripped from Purnea(PG) end. After this, fault current continued to feed from Purnea(PG) end through Circuit 2 ,220 KV Madhepura GSS Main Bus and Circuit 1 resulting in tripping of Circuit 1 at Madhepura GSS end and trripping of Circuit 2 at Purnea(PG) end.

132 kV Supaul - Phoolparas D/C, 132 kV Kataiya - Duhabi S/C and 132 kV Kataiya - Forbisgunj T/C were under breakdown due to flood condition. BSPTCL and Powergrid may explain.

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Deliberation in the meeting BSPTCL informed that there was a Y-B-N fault in 220 KV Purnea(PG)-Madhepura line –I and the line tripped from both ends on zone 1. Powergrid informed that 220 KV Purnea(PG)-Madhepura line –II also tripped from Purnea(PG) end on zone 3. ERLDC informed that as per PMU data the fault clearing time was within 80 ms. PCC felt that 220 KV Purnea(PG)-Madhepura line –II should not trip for a fault in line –I. PCC analyzed the both end DRs of 220 KV Purnea(PG)-Madhepura line –I and it was observed that Purnea(PG) end has issued the trip command immediately without any time delay after the fault pickup in zone 3. Madhepura end distance relay has seen the fault in reverse zone for 150 ms. PCC advised Powergrid to check the relay of 220 KV Purnea(PG)-Madhepura line –I at Purnea(PG) end. PCC advised BSPTCL to check the healthiness of CB of 220 KV Purnea(PG)-Madhepura line –I at madhepura end. ITEM NO. B.6: Repeated disturbances at 132 kV Rangit, Kurseong, Melli and Rangpo on 30-

08-17 at 05:15 hrs and 31-08-17 at 00:39 hrs 30-08-17 at 05:15 hrs: At 5:15 hrs. 132 KV Siliguri-Kurseong S/C, 132 KV Siliguri Melli S/C and 132 KV Rangit-Rangpo S/C tripped on R-B-N fault. As a result, all running units of Rangit(3 x 20 MW) tripped on over frequency and subsequently,132 KV Rangit-Kurseong S/C and 132 KV Rangit-Sagbari S/C were hand tripped. 31-08-17 at 00:39 hrs At 00:39 hrs. 132 KV Siliguri-Kurseong S/C, 132 KV Siliguri Melli S/C and 132 KV Rangit-Rangpo S/C tripped on R-B-N fault. As a result, all running units of Rangit(3 x 20 MW) tripped on over

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frequency and subsequently,132 KV Rangit-Kurseong S/C and 132 KV Rangit-Sagbari S/C were hand tripped. Powergird and NHPC may explain. Deliberation in the meeting Powergrid informed that fault was in both 132 KV Siliguri-Kurseong S/C and 132 KV Siliguri-Melli S/C lines due to lightening strike as both the lines are in same tower. Both the lines tripped from Siliguri end on zone 1. NHPC informed that Rangit units tripped on over frequency due to non availability of evacuation path. PCC advised Powergrid to send the complete details along with sequence of tripping and DR to ERPC and ERLDC for further analysis. ITEM NO. B.7: Disturbance at 400/132 kV Banka S/s on 21-08-17 at 13:50 hrs At 13:04 Hrs, 132 KV Banka-Sultanganj D/C tripped due to B-N fault (FAULT LOCATION=8.4KM, FAULT CURRENT= 6.45KA). While attempting charging of Ckt II at 13:30 Hrs from Banka, CB of the line stucked. LBB operated and tripped all the elements connected to 132kV main bus along with both 400/132 KV ICTs. Relay indications:

After patrolling it was found that at location no-27 of Banka-Sultanganj overhead line crossing 132KV D/C Banka-PG Sabour line between location no 112-113, at that location it was found that the earth wire of Banka(PG)-Sabour line was having clearance of less than a foot from B-ph of Banka(PG)-Sultanganj line of both circuits.This happend due to ongoing stringing works of OPGW of Banka PG -Sabour line as they were working at location no-112. After attaining required clearance by lowering of earth wire the Banka PG-Sultanganj line ckt1 was charged at 20:05 Hrs and ckt2 at 20:30 hrs. BSPTCL and Powergrid may explain. Deliberation in the meeting BSPTCL informed that B-N fault occurred in 132 KV Banka-Sultanganj D/C line at loc. No. 112 during OPGW stringing work of 132kV Banka(PG)-Sabour line. During investigation they found that the clearance between the ground wire of 132kV Banka(PG)-Sabour line and B-ph of 132 KV Banka-Sultanganj D/C line is less at location no. 112.

59th PCC Minutes 8

BSPTCL explained that 132kV Banka-Sultanganj D/C line tripped from both ends on zone 1. Thereafter, the CB at Banka got stuck due to SF6 gas lock out while Powergrid was trying to charge 132 KV Banka-Sultanganj line II from Banka end. LBB operated at Banka and tripped all the elements connected to 132kV bus at Banka. Banka end CB of 132 KV Banka-Sultanganj line II operated successfully during LBB operation. Powergrid informed that CB is the property of BSPTCL. BSPTCL informed that required clearance has been between provided for 132 KV Banka-Sultanganj D/C line and 132kV Banka(PG)-Sabour line. PCC advised BSPTCL to check the healthiness of CB of 132 KV Banka-Sultanganj line II at Banka end. ITEM NO. B.8: Disturbance at 400 kV Teesta and Dikchu on 04-08-17 at 13:46 hrs

400 KV Teesta III-Dikchu S/C tripped at 13:46 Hrs due to operation of directional O/c relay at Teesta III end. The line did not trip from Dikchu end. In PMU data, no voltage dip has been observed. As per Teesta III end DR of 400 kV Teesta III-Dikchu S/C line, Dir. O/C picked up at 13:46:27.677 hrs, B phase current was 1.3 kA. As per Teesta III end DR of Teesta III Rangpo Cable, B/up O/C and B/up E/F picked up at 13:46:27.462 hrs. Siemens relay Backup overcurrent IDMT characteristics operated at 2345 ms. Teesta Urja Ltd. and Dikchu may explain. Deliberation in the meeting Teesta Urja Ltd. explained the tripping with a presentation. Presentation is enclosed at Annexure-B8. Teesta Urja Ltd. explained that 400kV Teesta III – Dikchu line tripped on backup Earth fault O/C protection of cable from Teesta III end and earth fault pickup observed in other relays. Fault current was very less 1.3 kA (approx). Siemens relay Backup overcurrent operated at 2345 ms as per the settings of IDMT characteristics. ITEM NO. B.9: Disturbance at 400kV Teesta-III, Dikchu and Rangpo S/s on 16-08-17 at 12:18

hrs At 12:18 Hrs, 400 KV RANGPO - TEESTA-3 S/C tripped on B-N fault (Rangpo end: B-N, Z-II, F/C 4.49 kA, 54.7 km and Teesta III end: B-N, Z-I) due to conductor snapping at tower no 23 resulting in outage of units # I, II, III, IV, V & VI (879 MW) at Teesta - III and unit I & II at Dikchu (100 MW) due to loss of evacuation path. Attempt was taken to charge the line from Rangpo end at 12:41 hrs but it immediately tripped in SOTF.

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Teesta III end of 400 KV RANGPO - TEESTA-3 S/C line tripped without any attempt of auto-reclose. Teesta Urja Ltd. may explain. Deliberation in the meeting Teesta Urja Ltd. explained the tripping with a presentation. Presentation is enclosed at Annexure-B9. Teesta Urja Ltd. explained that auto reclose scheme for 400 KV RANGPO - TEESTA-3 S/C line is not yet implemented at Teesta III end because of some cable portion. Powergrid informed that auto reclose scheme is in service at Rangpo end and auto reclose attempted on 16-08-17. On enquiry, Teesta Urja Ltd. Informed that auto reclose scheme can be implemented at Teesta III end. PCC advised Powergrid and Teesta III to coordinate and implement the auto reclose scheme at both ends. ITEM NO. B.10: Disturbance at 220kV Hatia on 03-08-17 at 11:45 hrs 220 kV Ranchi - Hatia D/C and 220 kV Patratu - Hatia D/C along with all 220/132 kV ATR at Hatia end tripped due to DC failure of Hatia S/S. JUSNL may explain. Deliberation in the meeting JUSNL explained that short circuit occurred while replacing the batteries of 220 V DC system. Hence capacitor tripping device operated and tripped all the lines connected to 220kV main bus at Hatia. ITEM NO. B.11: Disturbance at 220 kV Meramundali S/s on 01-08-17 at 13:32 hrs. At 13:07 hrs, one mentally challenged person entered into the substation and tried to climb the switchyard tower. To avoid unwanted accident all the emanating lines / ICTs from 220KV Meramundali were hand tripped. OPTCL may explain. Deliberation in the meeting OPTCL explained that one mentally challenged person entered into the substation and tried to climb the switchyard tower. On enquiry, OPTCL informed that boundary wall of the switch yard is broken at few places. PCC advised OPTCL to repair the boundary wall and take appropriate action to avoid such incidences. OPTCL informed that they are repairing the boundary wall and increased the security personals in the switchyard. ITEM NO. B.12: Format of First Hand Trip report for any tripping incident--ERLDC As per IEGC section 5.9.6 (a), users, STU, CTU, SLDC are to give written report along with oral information for tripping of any regional grid element and protection failure on any element of ISTS,

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and on any item on the “agreed list” of the intra-State systems. Format for written first hand trip report for the above mentioned events is attached in Annexure-B12. Users, STU, CTU and SLDCs in Eastern Region have to submit first hand report to ERLDC as per the format, failing which it will be considered as non-submission first-hand information. Members may note and comply. Deliberation in the meeting PCC advised all the constituents to submit the tripping incident report as per the format given in Annexure. ITEM NO. B.13: Standardizing DR digital channel name--ERLDC Standardized naming convention may be followed for digital channel names of disturbance recorder (DR) output to ease the correct analysis of any tripping incident. In some cases, “virtual input” is used as digital channel names of DR output, which may be substituted with standardized names. If any digital channel name cannot be standardized, meaning of all digital channel names of DR output may be uploaded in PDMS. Members may note and comply. Deliberation in the meeting It was informed that ERPC and ERLDC is facing problem while analyzing the DRs because of improper digital channel names. PCC advised all the constituents to configure the disturbance recorder in numerical relay properly with standard channel names.

PART- C:: OTHER ITEMS

FOLLOW-UP OF DECISIONS OF THE PREVIOUS PROTECTION SUB-COMMITTEE MEETING(S)

(The status on the follow up actions is to be furnished by respective constituents) ITEM NO. C.1: Repeated disturbances at 400kV Teesta-III, Dikchu and Rangpo on at 00:30

hrs on 16-07-2017, 15:56 hrs & 19:11 hrs on 24-07-2017 and 10:08 hrs on 27-07-2017

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At 00:30 hrs on 16-07-2017: 400 kV Teesta III - Dikchu S/C (tripped only from Teesta III end) and Unit #I at Dikchu tripped due to operation of cable differential protection (B phase current 1.1 kA at Teesta III) resulting generation loss at Unit # II at Dikchu due to loss of evacuation path. At 15:56 hrs on 24-07-2017: 400 kV B/C at Teesta III tripped on receipt of SPS signal resulting in tripping of unit I, II & IV. However both circuits of 400 kV Rangpo - Binaguri D/C were in service. Flow in 400 kV Rangpo - Binaguri D/C was around 800 MW/Ckt. Rangpo personnel verbally confirmed non increment of TX counter dedicated for transmitting SPS signal. At 19:11 hrs on 24-07-2017: Due to Rotor Earth Fault in Unit #5 of Teesta III there was a dip in DC Voltage during Unit 5 Start-up (DC Field Flushing) leading other synchronized units to No Load Operation. At 10:08 hrs on 27-07-2017: At 10:08 hrs 400 kV Rangpo – Binaguri – II tripped due to B-N fault. (DEF, F/C at Rangpo and DT received at Binaguri). After tripping of circuit – II, power flow in 400 kV Rangpo – Binaguri – I became more than 850 MW (1700 MW approx.) and SPS – I (generation reduction at Teesta III, Dikchu, JLHEP and Chujachen.) got activated resulting tripping of one unit at each power plant at Chujachen, JLHEP and Dikchu. Due to non-tripping of any unit at Teesta III, power flow in 400 kV Rangpo – Binaguri – I remained more than 850 MW for more than 500 ms and SPS – II got activated resulting tripping of 400 kV Teesta III – Rangpo S/C followed by tripping of remaining units at Teesta III and Dikchu due to loss of evacuation path. In 58th PCC, it was informed that only Teesta III station has received SPS trip signal at 15:56 hrs on 24-07-2017 but Rangpo end confirm non-transmission of SPS signal. Hence it may be a spurious tripping. In other instance at 10:08 hrs on 27-07-2017, Teesta-III did not provide generation relief when 400 kV Rangpo – Binaguri – II tripped and SPS operated at Rangpo. PCC felt that this kind of inadvertent SPS operations of Teesta-III may endanger the grid security and advised Teesta-III to check and review the SPS at their end. PCC opined that in view of repeated unsatisfactory SPS operations during last few months, the threshold limit on power flow through 400 kV Rangpo – Binaguri D/C line needs to be reviewed. In last few OCC meetings, Teesta-III, Jorethang, Dikchu, Chuzachen & Powergrid were not submitting the healthiness certificate for Rangpo SPS as per the decision of special meeting of 21.06.2017. The issue was referred to TCC. In 36th TCC, Teesta-III explained that on 24-07-2017 at 15:56 hrs the tripping was initiated at Teesta III because of PLCC maloperation due to fault in DC system during DC field flushing. Teesta-III informed that now they are following to AC field flushing in order to avoid the DC voltage dip. Teesta-III explained that on 27-07-2017 at 10:08 hrs, they have not received the SPS signal due to some problem in PLCC panel. The same has been rectified and successfully operated on 19th August 2017.

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Further Teesta-III suggested that second PLCC channel may also be used for transferring the signal from Rangpo to Teesta III to improve the reliability. Teesta III added that spare channel is already available. Teesta Urja Ltd. may update. Deliberation in the meeting Teesta Urja Ltd. explained the trippings with detailed presentation. Presentation is enclosed at Annexure-C1. Teesta Urja Ltd. informed that second PLCC channel can be used for transferring the signal from Rangpo to Teesta III to improve the reliability. They are ready to implement at their end. Powergrid informed that this was planned much earlier but they need a decoder at Rangpo end to implement. Purchasing of decoder is in process and Teesta Urja Ltd. has to born the cost for implementing the second PLCC channel. ITEM NO. C.2: Disturbance at 220 kV Lalmatia S/s(JUSNL) on 21-05-17 at 16:39 hrs. At 16:39 hrs 220 kV Farakka Lalmatia S/C line tripped from Farakka end on O/C E/F protection F/C 4.68 kA in B phase at Farakka. 132 KV Kahalgaon(BSPTCL) - Lalmatia S/C & 132 KV Kahalgaon(NTPC)-Lalmatia S/C were also tripped resulting total loss of power supply at Lalmatia & Sahebgunj. Load at Dumka got survived as it was radially fed from Maithon.

JUSNL and NTPC may explain the following:

Location of fault Tripping of 220 kV Farakka Lalmatia S/C line Tripping of 132 KV Kahalgaon(BSPTCL) - Lalmatia S/C & 132 KV Kahalgaon(NTPC)-

Lalmatia S/C In 56th PCC, NTPC informed that 220kV Farakka-Lalmatia line tripped from Farakka end on B-N fault, the fault distance was 59 km. 132 KV Lalmatia- Kahalgaon line didn't trip from Kahalgaon end. However DR recorded in relay of this line indicates that aforesaid line tripped at Lalmatia end. PCC advised NTPC to collect tripping details of 220kV Farakka-Lalmatia line at Lalmatia end and submit to ERLDC and ERPC. In 58th PCC, NTPC informed that submitted the DR of Farakka end for 220kV Farakka-Lalmatia line tripping. PCC advised NTPC to collect tripping details of 220kV Farakka-Lalmatia line at Lalmatia end also and submit to ERLDC and ERPC. JUSNL and NTPC may update. Deliberation in the meeting NTPC informed that 220kV lalmatia-farakka line tripped from Lalmatia end on distance protection fault distance 30km from Lalmatia end. At the same time, 132kV Lalmatia-kahalgaon line tripped form Lalmatia end only on O/C, E/f protection. PCC felt that 132 KV Lalmatia- Kahalgaon line should not trip from Lalmatia end and advised JUSNL to check the Lalmatia end relay.

59th PCC Minutes 13

ITEM NO. C.3: Multiple elements tripping at 220/132 kV Lalmatia (JUSNL) S/s on 06-02-17 at 16:40 Hrs.

At 16:40hrs, blasting of 132 kV Y & B phase CTs of 132 kV bus sectionalizer at 220/132kV Lalmatia S/s resulted in following events:

132 kV Lalmatia - Kahalgaon and 132 kV Lalmatia - Dumka – II tripped from Lalmatia end on zone IV protection.

132 kV Lalmatia -Dumka – I feeder tripped from both end. Farakka end of 220 kV Farakka Lalmatia line, remain picked up the fault in zone 1 for 880

ms but no line breaker was tripped.

The relay Indications are as follows:

Time Name of the element Relay at Lalmatia Relay at remote end 16:40 hrs

220 kV Lalmatia - Farakka feeder

Did not trip R-Y-B phase Z-I started, B phase relay picked at 16:40:28.504 hrs, Y phase relay picked at 16:40:28.664 hrs, R phase relay picked at 16:40:28.905 hrs, F/C 1.5 kA in all three phases. All the relay were in picked condition till the end of time frame captured by NTPC end DR (DR is attached)

132 kV Lalmatia -KhSTPP feeder

B-N, Z-IV, O/C, IA 0.7kA, IB – 0.9 kA, IC – 3kA, Fault duration 183.8 ms.

Did not trip

132 kV Lalmatia Dumka – I

E/F D/P

132 kV Lalmatia Dumka – II

E/F, Z-IV Did not trip

220/132 KV ATR, 132/33 KV ATR – I & II at Lalmatia

E/F protection at Lalmatia

Analysis of PMU plots:

At 16:40 hrs, 4 kV voltage dip observed in all three phases. Fault clearance time is 700 ms. Though the voltage fully recovered to pre-fault value after

600 ms of the fault. In 53rd PCC, NTPC informed that 132 kV Y & B phase CTs of 132 kV bus sectionalizer were busted at 220/132kV Lalmatia S/s and Bus bar protection was failed to operate. One 220/132kV ATR at Lalmatia (under NTPC control area) tripped on backup E/F protection other ATR which is under JUSNL control area was failed to clear the fault. As a result, 220kV Lalmatia-Farakka line tripped from Farakka end on directional E/F protection. JUSNL informed that 132kV Lalmatia-Dumka D/C line and 132kV Lalmatia-Khahalgaon S/C line tripped from Lalmatia end on non directional over current protection. The 220/132kV ATR at Lalmatia under their control area also tripped on over current E/F protection. PCC observed that 220kV Lalmatia-Farakka line tripped from Farakka end after 6 sec which is not acceptable and tripping of 220/132kV ATRs is not clear. PCC advised the following:

NTPC should check the reason for non-operation of busbar protection at 132kV Lalmatia S/s.

NTPC and JUSNL should jointly test the healthiness of the busbar protection at 132kV Lalmatia S/s

NTPC and JUSNL should place the details of ATR tripping along the relevant DR.

59th PCC Minutes 14

JUSNL should disable the non-directional over current protection feature in all 132kV lines and enable directional over current protection with proper relay coordination.

PCC advised JUSNL and NTPC to submit the action taken report to ERPC and ERLDC within a week. In 54th PCC, NTPC and JUSNL informed that they will test the healthiness of the busbar protection at 132kV Lalmatia S/s in May 2017. JUSNL informed they have not yet disabled the non-directional over current protection feature in all 132kV lines. In 58th PCC, JUSNL informed that they have disabled the non-directional over current protection feature in all 132kV lines and enabled directional over current protection on 30th July 2017. PCC advised JUSNL and NTPC to comply the other observations and submit the action taken report to ERPC and ERLDC. NTPC and JUSNL may update. Deliberation in the meeting PCC advised JUSNL and NTPC to comply the other observations and submit the action taken report to ERPC and ERLDC. ITEM NO. C.4: Disturbance at 765 kV Dharmajaygarh S/s on 15-06-17 at 14:23 hrs. At 14:23:12.417, distance protection of Dharamjaigarh-Jabalpur Ckt-3 issued trip command on R-Y fault at both ends. At Dharamjaigarh end, main CB tripped, however, none of the poles of Tie CB tripped, thus all the connected lines tripped on Zone-3 from remote end. LBB did not operate at Dharamjaigarh due to failure in DC supply. Fault was cleared after tripping of 765kV Dharamjaigarh-Ranchi - II after 4 minutes from the fault. In 57th PCC, Powergrid explained that R-Y fault occurred in 765kV Dharamjaigarh-Jabalpur Ckt-3, main CB at Dharamjaigarh end tripped, but none of the poles of Tie CB tripped. LBB at 765kV Dharamjaigarh also not operated due to some problem in DC supply. As a result, all the connected lines of 765kV Dharamjaigarh tripped from remote end on Zone-3. But Ranchi end of 765kV Dharamjaigarh-Ranchi line- II tripped after 4 minutes. Powergrid informed that Ranchi end relay observed power swing hence the power swing blocking was initiated and blocked the relay to trip the line. PCC felt that fault in 765kV network was cleared after 4 minutes is not acceptable. Moreover Powergrid did not send any report to ERPC and ERLDC in this regard. PCC advised Powergrid to analyze the tripping and submit a detailed report to ERPC and ERLDC. Powergrid vide mail dated 30th Aug 2017 informed that during investigation of delayed tripping, the zone 3 reach setting was found slightly less than the calculated zone 3 reach value. This might caused delay in pickup and drop of zone 3. The zone 3 reach setting has been corrected. In 36th TCC, ERLDC informed that though they have sent the DR, the relevant DR containing the tripping instant is missing. ERLDC asked that how 765kV Dharamjaigarh-Ranchi line- II only observed the power swing when parallel line (765kV Dharamjaigarh-Ranchi line- I) had successfully cleared the fault in time.

59th PCC Minutes 15

Powergrid informed that line length of both the ckts are different and the zone 3 setting of 765kV Dharamjaigarh-Ranchi line- II at Ranchi end was slightly less than the calculated zone 3 reach value. TCC felt that delayed fault clearance of fault in 765 kV level may be resulted to serious threat for grid security. TCC advised Powergrid to take the issue seriously and present detail analysis on delayed tripping of 765kV Dharamjaigarh-Ranchi line- II form Ranchi end with all the explanation in forthcoming PCC meeting scheduled to be held on 20th September 2017. Powergrid may explain. Deliberation in the meeting Powergrid explained the disturbance with detailed presentation. Presentation is enclosed at Annexure-C4. Powergrid explained that

765kV Dharamjaigarh-Ranchi line- I at Ranchi has picked up the fault in zone 3 on the boundary and initiated the tripping after 1 sec. correctly.

Although 765kV Dharamjaigarh-Ranchi line- I at Ranchi end picked up the fault just on the boundary of Zone-3, 765kV Dharamjaigarh-Ranchi line- II at Ranchi end observed the fault in zone 3 the fault remained in Zone-3 for 100-500ms duration in 4 instances due to lower zone 3 setting.

Hence the distance relay of 765kV Dharamjaigarh-Ranchi line- II at Ranchi end not initiated trip command for first 3 minutes.

After approx 3 minutes, the fault re-appeared in Zone-3 of 765kV Dharamjaigarh-Ranchi line- II at Ranchi end and persisted for 1 second, resulting in the tripping of the Ranchi-Dharamjaigarh Circuit-2.

Powergrid added that the zone 3 reach setting of 765kV Dharamjaigarh-Ranchi line- II at Ranchi end has been corrected. ITEM NO. C.5: Station blackouts at 220kV MTPS Station Blackout being faced at MTPS due to tripping of 220KV MTPS-Kaffen Ckt-1 & 2 on various reasons. It may be noted that above lines are connected to the grid, while remaining lines emanating from MTPS remain connected in radial mode. Though 220KV MTPS-Motipur Ckt-1 and 220KV MTPS-Ujiayarpur Ckt-2 has grid connectivity, but these two lines are also most of the times kept on radial mode by SLDC, Patna due to power flow constraints. Following three incidents Kaffen Ckt-1 & 2 trippings resulted in Station Blackout at KBUNL. This causes not only heavy loss to KBUNL but heavy stress on machines due to sudden power failure. North Bihar area which is connected with the MTPS with 6 Nos. 220KV & 7 Nos. 132KV lines also goes in dark during above period. 1. TRIPPING OF 220KV MTPS-KAFFEN CKT-1 & 2 FROM KAFFEN END ON 20.06.2017, 08:42

HRS RESULTING IN UNIT-2 TRIPPING AND THUS STATION BLACKOUT.

2. TRIPPING OF 220KV MTPS-KAFFEN CKT-1 & 2 DUE TO PLCC MALFUNCTION ON 07.05.2017, 14:41 HRS RESULTING IN UNIT-1 TRIPPING AND THUS STATION BLACKOUT.

3. TRIPPING OF 220KV MTPS-KAFFEN CKT-1 & 2 DUE TO PLCC MALFUNCTION ON 18.04.2017, 22:55 HRS RESULTING IN STATION BLACKOUT.

In 57th PCC, Powergrid informed that the relays of 220KV MTPS-Kaffen Ckt-1 & 2 at Kaffen(PG) were not functioning properly. The relays have been replaced with new relays.

59th PCC Minutes 16

Regarding malfunction of PLCC system of 220KV MTPS-Kaffen Ckt-1 & 2, Powergrid informed that BPL make PLCC system has been rectified and now it is in order. Regarding installation of PLCC system in other 220kV lines, BSPTCL informed that they have given consultancy to Powergrid for installing of OPGW in three 220kV lines. PCC advised BSPTCL to place their action plan for installation of PLCC system in other transmission lines. In 58th PCC, BSPTCL informed that PLCC system for 220kV MTPS-Motiari line is available at site. Clearance from MTPS end is awaited for installation of PLCC system. BSPTCL may update. Deliberation in the meeting PCC advised BSPTCL to submit their action plan to restore the PLCC system. ITEM NO. C.6: Concerned members may update the latest status.

1. Disturbance at 220 kV Hatia, Biharsharif and Fatua S/s on 05-06-17 at 20:27 hrs. In 57th PCC, PCC recommended the following:

PCC felt that 220/132kV ATRs at 220kV Hatia S/s should not trip for a fault in 220 kV Ranchi – Hatia line-I and advised JUSNL to check the relays of 220/132kV ATRs at 220kV Hatia S/s

220 kV TVNL – Biharshariff S/C line should not trip from TVNL end on zone 2 in this case. PCC advised TVNL to review the zone 2 settings of 220 kV TVNL – Biharshariff S/C line at TVNL end.

JUSNL and TVNL may update. Deliberation in the meeting PCC advised JUSNL and TVNL to comply the observations at the earliest.

2. Disturbance at 220 kV Fatua S/s (BSPTCL) on 15-06-17 at 06:23 hrs. In 57th PCC, BSPTCL was advised to take the following corrective actions:

CB of 220 kV Sipara - Fatuah S/C line at Fatuah end should be tested. Non directional over current feature should be disabled for 220 kV Biharshariff - Fatuah – I at

Fatua end and backup directional over current protection should be properly coordinated with distance protection.

In 58th PCC, BSPTCL informed the following:

They are planning to test CB of 220 kV Sipara - Fatuah S/C line at Fatuah end and submit the report after testing.

Non directional over current feature has been disabled for 220 kV Biharshariff - Fatuah – I at Fatua end and backup directional over current protection was properly coordinated with distance protection.

CB of 220 kV Biharshariff - Fatuah – II at Fatua end has been tested and found that opening time is higher and they are planning to replace the breaker.

BSPTCL may update.

59th PCC Minutes 17

Deliberation in the meeting BSPTCL informed that work is in progress.

3. Disturbance at 220 kV Hazipur (BSPTCL) on 11-06-17 at 11:39hrs. In 57th PCC, members felt that zone 2 time settings of 220 KV Muzaffarpur-Hazipur-D/C line at Muzaffarpur (PG) end should be verified as the PMU fault clearing time was 100 ms. PCC advised Powergrid to review the zone 2 time setting of 220 KV Muzaffarpur-Hazipur-D/C line at Muzaffarpur (PG) end. PCC advised BSPTCL to collect the details of 220 KV Hazipur -Amnour line- I at Amnour end and send it to ERPC and ERLDC. Powergrid and BSPTCL may update. Deliberation in the meeting Powergrid informed that the zone 2 time setting of 220 KV Muzaffarpur-Hazipur-D/C line at Muzaffarpur (PG) end has been changed to 300 ms. ITEM NO. C.7: Repeated pole blocking at HVDC Sasaram

S. No.

Tripping Date

Tripping Time

Brief Reason/Relay Indication

Restoration Date

Restoration Time

Duration

1 17-07-17 5:41 System failure alarm 17-07-17 6:38 0:57 2 17-07-17 16:35 System failure alarm 17-07-17 17:34 1:00:00 3 20-07-17 8:29 System failure alarm 20-07-17 9:25 0:56 4 31-07-17 18:34 System failure alarm 31-07-17 19:45 1:11:00 5 29-05-17 00:15 System failure alarm 29-05-17 01:24 1:09:00 6 25‐04‐17 06:03 Auxiliary supply

failure 25‐04‐17 07:14 1:11:00

7 01‐04‐17 09:15 Tripped due to Valve cooling system problem

01‐04‐17 12:56 3:41:00

8 11‐04‐17 23:32 System failure alarm 12‐04‐17 00:17 0:45:00 9 30‐04‐17 03:24 Due to tripping of

filters on eastern side 30‐04‐17 16:13 12:49:00

10 12‐01‐17 13:36 Blocked due to unbalanced auxiliary system

12‐01‐17 15:06 1:30:00

11 14‐01‐17 05:03 Tripped due to system failure alarm

14‐01‐17 08:57 3:54:00

12 10‐01‐17 13:23 Filter problem at Sasaram

12‐01‐17 11:24 46:01:00

13 03‐01‐17 11:00 To take pole in service in HVDC mode

10‐01‐17 07:42 164:42:00

14 03‐12‐16 12:15 Converter control protection operated

03‐12‐16 13:22 1:07:00

15 06‐12‐16 19:12 Tripped due to CCP east side M1, M2 major alarm and observed sys

06‐12‐16 20:55 1:43:00

59th PCC Minutes 18

fail in East side

16 19‐12‐16 12:43 Due to tripping of 400 kv Biharshariff‐Sasaram‐II

19‐12‐16 13:35 0:52:00

17 05‐11‐16 04:51 System fail alarm 05‐11‐16 06:57 2:06:00 18 22‐11‐16 12:12 CCP Main‐2 major

alarm 22‐11‐16 13:35 1:23:00

19 26‐11‐16 09:36 CB filter bank burst 27‐11‐16 11:31 25:55:00 Regarding pole block on 25-05-17, there is back up in the station in the following form: 132/33 KV Pusauli

315 MVA ICT-2 tertiary

01 No. DG set of 1500 KVA

Battery available for valve cooling system only. It can provide auxiliary supply for at max 2 minutes.

In 56th PCC, Powergrid was advised to submit the details to ERLDC and ERPC. In 36th TCC, Powergrid informed that pole blocking at HVDC Sasaram system is being initiated on system failure alarm. They have contacted OEM and OEM is also failing to conclude and rectify the issue. Powergrid added that since the HVDC control system is quite old and it is not operating satisfactorily the HVDC control system at Sasaram needs to be upgraded. Powergrid requested TCC to consider. TCC felt that Powergrid has not placed any report in the PCC meeting and advised Powergrid to take the issue seriously. TCC opined that system upgradation needs detailed discussion in lower forums and advised Powergrid to place the details in forthcoming PCC meeting scheduled to be held on 20th September 2017. Powergrid may update. Deliberation in the meeting Powergrid informed that the issue has been referred to their corporate office and they will submit the report soon. ITEM NO. C.8: Implementation of on-line tripping incident reporting system in Protection

Database Management System. On-line tripping incident reporting system has been implemented in Protection Database Management System (PDMS). As decided in 53rd & 54th PCC Meetings, details of the tripping incident along with the DR, EL events and other reports can be uploaded through this online portal. The tripping incident reporting page can be accessed in PDMS through the ERPC protection database website: www.erpc-protectiondb.in:8185. The link is also available in ERPC website on right side bar. Training on PDMS including on-line tripping incident reporting was given to all the constituents from 22.05.17 to 24.05.17. Subsequently, login ID and password for access of PDMS has been issued to the respective members as nominated by the authorities. ERPC vide letter dated 12th July 2017 informed all the constituents to submit the tripping incident report along with DR (comtrade files), EL and other relevant files through this on-line portal with immediate effect.

59th PCC Minutes 19

In 57th PCC, all the constituents were advised to submit the tripping incident report along with DR (comtrade files), EL and other relevant files through this on-line portal. PCC decided to consider both hard copy and details uploaded in the on-line portal for the month of August, 2017. PCC decided to consider only the on-line tripping incident report as received in PDMS from 1st September, 2017. In 58th PCC, all the constituents were advised to send their queries to mserpc-power@nic.in & eeop.erpc@gov.in if they are facing any problem in uploading the tripping details. In 36th TCC, TCC advised all the constituents to upload the tripping details of a month in networks under respective control area along with DR (comtrade files), EL and other relevant files in PDMS on-line portal, otherwise it will be considered as violation of compliance of clause 5.2(r) & 5.9 of IEGC. The status of online-tripping reporting in PDMS for the disturbances of August, 2017 as follows:

Sl No

UTILITY NAME TRIPPING INCIDENT

OCCURRENCE DATE

UPLOAD STATUS IN PDMS

1 OPTCL 220kV MERAMUNDALI-BSL 1 Tripping 01-08-2017 YES

2 JUSNL 220kV HATIA-RANCHI and 220kV HATIA-PTPS Tripping 03-08-2017 YES, Details not uploaded

3 TEESTA-3 (TUL) 400kV TEESTA-3 to Dikchu Line Tripping 04-08-2017 YES

4 WBPDCL Disturbance at Bakreswar TPP 11-08-2017 YES

5 PGCIL-ER1 Disturbance at Sasaram 12-08-2017 YES

6 BSPTCL Tripping of 220kV Purnea-Madhepura D/C 14-08-2017 YES, Relay indications not uploaded

7 TEESTA-3 (TUL) 400kV TEESTA-3 to RANGPO Line Tripping 16-08-2017 YES

8 BSPTCL Tripping of 132kV BANKA-SULTANGANJ D/C and ICTs at BANKA

21-08-2017 YES

9 DVC Disturbance at Waria S/S 27-08-2017 YES

10 DVC Multiple tripping at CTPS-B and Bokaro A 28-08-2017 YES

11 NHPC Power Failure at Rangit Station 30-08-2017

Rangit end details uploaded. Other line tripping details not uploaded.

12 NHPC Power Failure at Rangit Station 31-08-2017

Rangit end details uploaded. Other line tripping details not uploaded.

59th PCC Minutes 20

Members may comply. Deliberation in the meeting ERPC updated the status as mentioned in above table. PCC advised JUSNL, Powergrid and BSPTCL to upload the pending tripping details in PDMS on-line portal. Constituents informed that they are facing problems in selecting the line and relay in PDMS while uploading the tripping details. PCC advised all the constituents to send their queries to mserpc-power@nic.in & eeop.erpc@gov.in if they are facing any problem in uploading the tripping details. ITEM NO. C.9: Third Party Protection Audit 1. Status of 1st Third Party Protection Audit:

The compliance status of 1st Third Party Protection Audit observations is as follows:

Name of Constituents Total Observations Complied % of

Compliance Powergrid 54* 46 85.19 NTPC 16 14 87.50 NHPC 1 1 100.00 DVC 40 26 65.00 WB 68 27 39.71 Odisha 59 38 64.41 JUSNL 34 16 47.06 BSPTCL 16 5 31.25 IPP (GMR, Sterlite and MPL) 5 5 100.00

* Pending observations of Powergrid are related to PLCC problems at other end. The substation wise status of compliance are available at ERPC website (Observations include PLCC rectification/activation which needs a comprehensive plan).

Members may update. Deliberation in the meeting PCC advised all the constituents to comply the observations at the earliest. 2. Schedule for 2nd Third Party Protection Audit:

The latest status of 2nd Third Party Protection audit is as follows:

1) Jeerat (PG) Completed on 15th July 2015 2) Subashgram (PG) Completed on 16th July 2015 3) Kolaghat TPS (WBPDCL)- Completed on 7th August 2015 4) Kharagpur (WBSETCL) 400/220kV - Completed on 7th August 2015 5) Bidhannagar (WBSETCL) 400 &220kV Completed on 8th September, 2015 6) Durgapur (PG) 400kV S/s Completed on 10th September, 2015 7) DSTPS(DVC) 400/220kV Completed on 9th September, 2015 8) Mejia (DVC) TPS 400/220kV Completed on 11th September, 2015

59th PCC Minutes 21

9) 400/220/132kV Mendhasal (OPTCL) Completed on 2nd November, 2015 10) 400/220kV Talcher STPS (NTPC) Completed on 3rd November, 2015 11) 765/400kV Angul (PG) Completed on 4th November, 2015 12) 400kV JITPL Completed on 5th November, 2015 13) 400kV GMR Completed on 5th November, 2015 14) 400kV Malda (PG) Completed on 23rd February, 2016 15) 400kV Farakka (NTPC) Completed on 24th February, 2016 16) 400kV Behrampur(PG) Completed on 25th February, 2016 17) 400kV Sagardighi (WBPDCL) Completed on 25th February, 2016 18) 400kV Bakreswar (WBPDCL) Completed on 26th February, 2016 19) 765kV Gaya(PG) Completed on 1st November, 2016 20) 400kV Biharshariff(PG) Completed on 3rd November, 2016 21) 220kV Biharshariff(BSPTCL) Completed on 3rd November, 2016 22) 400kV Maithon (PG) Completed on 18th May, 2017 23) 132kV Gola (DVC) Completed on 17th May, 2017 24) 132kV Barhi (DVC) Completed on 18th May, 2017 25) 132kV Koderma (DVC) Completed on 18th May, 2017 26) 132kV Kumardhubi (DVC) Completed on 19th May, 2017 27) 132kV Ramkanali (DVC) Completed on 19th May, 2017 28) 220kV Ramchandrapur Completed on 1st June, 2017 29) 400kV Jamshedpur (PG) Completed on 1st June, 2017 30) 132kV Patherdih (DVC) Completed on 31st May, 2017 31) 132kV Kalipahari (DVC) Completed on 30th May, 2017 32) 132kV Putki (DVC) Completed on 31st May, 2017 33) 132kV ASP (DVC) Completed on 30th May, 2017 34) 132kV Mosabani (DVC) Completed on 2nd June, 2017 35) 132kV Purulia (DVC) Completed on 1st June, 2017

It was informed that the third party protection audit observations are available in the ERPC website in important documents. PCC advised all the constituents to comply the observations at the earliest. Members may update. Deliberation in the meeting PCC advised all the constituents to comply the observations at the earliest. ITEM NO. C.10: Implementation of Protection Database Management System Project. ERPC proposal for “Creation & Maintenance of web based protection database management system and desktop based protection calculation tool for Eastern Regional Grid” has been approved by the Ministry of Power for funding from Power System Development Fund (PSDF) vide No-10/1/2014-OM dated 07.03.2016. In 49th PCC, PRDC informed that data collection for West Bengal is in progress and it will be completed by December, 2016. In 50th PCC, It was informed that Software Acceptance Tests are in progress. In 51st PCC, PRDC informed that data collection of Odisha and Jharkhand has been completed. Data collection in West Bengal and Bihar is in progress. Data collection of Eastern Region will be completed by 15th February 2017. PRDC added that software acceptance trails of PSCT phase-I have been completed and phase-II will be done from 19th to 21st January 2017. Software acceptance trails of web based PDMS system have been completed and observations will be implemented at the earliest.

59th PCC Minutes 22

It was informed that a format for on-line reporting of tripping incidence has been prepared in PDMS and PRDC will present details in next PCC meeting. In 52nd PCC, PRDC explained the format for on-line reporting of tripping incidence. PCC suggested PRDC to include details of the elements under shutdown before the disturbance. In 53rd PCC, PRDC informed that data survey and modeling has been completed and PDMS will be operational by 31st March 2017. The login id will be provided soon. PRDC presented the format for on-line reporting of tripping incidence. PCC in principle agreed with the format and advised PRDC to include a summery sheet for the each tripping incidence. In 54th PCC, PRDC informed that summery sheet for on-line tripping incidence reporting has been prepared. The PDMS is operational and constituents can access the data. Login credentials were given to all the constituents. It was decided that a separate meeting will be convened in May 2017 to finalize the procedure for on-line reporting and data updation. In 55th PCC, PRDC informed that collection of relay settings 97 out of 112 substations were completed in Bihar. Rest are in progress. Pending relay setting file collection of JUSNL substations are in progress. Relay setting file collection of Sikkim substations are pending. In 56th PCC, PRDC informed that relay setting file collection of BSPTCL and Sikkim substations are in progress. In 58th PCC, It was informed that a special meeting will be held on 7th September 2017 at ERPC, Kolkata for validation of substation/relay data available at PDMS. PCC advised all the constituents to send their representative with all the relevant details. In 36th TCC, ERPC Secretariat informed that some relay setting data for protection database is still pending from constituents. The latest status as updated in special meeting on 7th September 2017 is given below: 1. Odisha: 92.77% 2. Jharkhand: 91.34% 3. West Bengal: 92.152% 4. Bihar: 70.617% (Powergrid ER-I data is pending) 5. Sikkim: 92.408% TCC felt that Ministry of Power is funding the project and it would be a gross negligence of ER constituents, if complete relay setting data were not provided for implementation of the project. TCC advised all the constituents to send the pending relay setting data to ERPC and also to check & verify their respective Substation data (relay data/SLD/CT/PT etc) as available in PDMS regularly and submit their observations as per the decision of 07.09.17. PRDC may update. Deliberation in the meeting Powergrid ER-I informed that they will send the data within a week.

59th PCC Minutes 23

ITEM NO. C.11: Non-commissioning of PLCC / OPGW and non-implementation of carrier

aided tripping in 220kV and above lines. According to CEA technical standard for construction of electric plants and electric lines -Clause 43(4) (c), transmission line of 220 KV and above should have single-phase auto-reclosing facility for improving the availability of the lines. However, from the tripping details attached June-August, 2016 it is evident that the some of 220kV above Inter & Intra-Regional lines do not having auto-reclose facility either at one end or at both ends. Out of these for some of the lines even PLCC/OPGW is not yet installed and carrier aided protection including Autorecloser facility is not yet implemented. Based on the trippings of June- August, 2016 and PMU analysis a list of such lines has been prepared and as given below:

List of line where auto reclose facility is not available(Information based on PMU data analysis)

S. No Transmission Lines name

Date of Tripping

Reason of Tripping

Owner Detail Present Status

End-1 End-2 OPGW/PLCC Link available

AR facility functional

10 400KV PATNA-BALIA-II 21.06.16 B-N FAULT PGCIL PGCIL

12 400KV PATNA-BALIA-I 21.06.16 R-N FAULT PGCIL PGCIL PLCC available

13 220KV BUDIPADAR-KORBA-II 23.06.16 Y-N FAULT OPTCL CSEB

PLCC available

will be activated in consultation with Korba

14 400 KV ARAMBAGH - BIDHANNAGAR 02.07.16 Y-N FAULT

WBSETCL

WBSETCL

PLCC available

AR in service but some problem in y-ph pole

16 400 KV NEW RANCHI - CHANDWA - I 13.07.16 B-N FAULT PGCIL PGCIL

PLCC available

17 220 KV TSTPP-RENGALI 17.07.16 EARTH FAULT NTPC OPTCL

18 220KV BUDIPADAR-RAIGARH 21.07.16

EARTH FAULT OPTCL PGCIL

PLCC defective

19 400 KV KOLAGHAT-KHARAGPUR 03.08.16 Y-N FAULT

WBPDCL

WBSETCL

20 220 KV FARAKKA-LALMATIA 03.08.16 B-N FAULT . NTPC JUNSL

Yes Old Relay and not functional. 7-8 months required for auto re-close relay procurement.

21 400 KV PURNEA-MUZAFARPUR-I 03.08.16 R-N FAULT PGCIL PGCIL

PLCC available

23 220 KV MUZAFFARPUR - HAZIPUR - II 10.08.16 B-N FAULT PGCIL BSPTCL

Voice established. For carrier required shutdown

24 220 KV ROURKELA - TARKERA-II 11.08.16 B-N FAULT PGCIL OPTCL

OPGW available

Expected to install

59th PCC Minutes 24

protection coupler by Jan 17

25 220 KV CHANDIL-SANTALDIH 25.08.16 R-N FAULT JUSNL

WBPDCL

not available

26 400 KV MPL-RANCHI-II 02.09.16 R-N FAULT MPL PGCIL PLCC available

27 220 KV BIHARSARIF-TENUGHAT 07.09.16 B-N FAULT

BSPTCL TVNL

29 220 KV RAMCHANDRAPUR - CHANDIL

22.09.16 B-N FAULT JUSNL JUNSL

31 400 KV KOLAGHAT - CHAIBASA 28.09.16 B-N FAULT

WBPDCL PGCIL

PLCC available

34th TCC advised all the respective members to update the above list along with the last tripping status in next PCC meeting. TCC further advised all the constituents to give the latest status of PLCC of other 220kV and above lines under respective control area. TCC advised to review the status of above in lower forums report back in next TCC. Members may update the status. Deliberation in the meeting Members noted. ITEM NO. C.12: Non-commissioning / non-functional status of bus-bar protection at

important 220 kV Sub-stations. It has been observed that at many 220 kV substations particularly that of STU, bus-bar protection is either not commissioned or non-functional. The non-availability / non-functionality of bus bar protection, results in delayed, multiple and uncoordinated tripping, in the event of a bus fault.This in turn not only results in partial local black out but also jeopardises the security of interconnected national grid as a whole. The matter was also pointed out during the third party protection audit which is being carried out regularly. Constituents are required to meet the audit compliance and commission or made bus –bar protection functional where ever it is not available. A list of such important 220 kV sub-stations as per the first third party audit is placed in the meeting. In 34th TCC, members updated the status as follows:

Bus Bar Protection not available (record as per third party protection audit)

Bihar Sl No Name of Substation

Bus Bar protection status

Date of audit Present Status

1 220 kV Bodhgaya Not available 28-Dec-12

Single bus and there is no space available for busbar protection

Jharkhand 1 220 kV Chandil Not available 29-Jan-13 LBB available 2 220 kV Tenughat Not available 12-Apr-13

59th PCC Minutes 25

DVC

1 220 kV Jamsedpur Not available 10-Apr-13

Single bus. Bus bar will be commissioned under PSDF.

West Bengal

1 220 kV Arambah Not available 24-Jan-13

Available in alarm mode. Planning to replace with numerical relay

2 220 kV Jeerat Not available 20-Dec-12

Relays have been received at site. Installation is in progress.

TCC further advised all the constituents to give the latest status of Bus Bar protection of other 220KV S/S under respective control area. TCC advised to review the status of above in lower forums report back in next TCC. 58th PCC advised DVC to install numerical bus bar protection at 220kV Bokaro, Kalyaneswari, Chandrapura and Durgapur S/s to improve the reliability. In 36th TCC, DVC informed that they have already covered the upgradation of busbar protection for 220kV Kalyaneswari and Durgapur in PSDF proposal. They will place their action plan for 220kV Bokaro and Chandrapura in upcoming PCC meeting. Members may update. Deliberation in the meeting Members noted.

PART- D

Item No D.1 Tripping incidences in the month of August, 2017 Other tripping incidences occurred in the month of August 2017 which needs explanation from constituents of either of the end is given at Annexure- D1. In 58th PCC, ERLDC informed that most of the constituents are not submitting the DR and EL data for single line trippings. PCC advised all the constituents to upload the details along with DR and EL in PDMS on-line portal and referred the issue to TCC for further guidance. In 36th TCC, all the constituents were advised to use the PDMS on-line portal for uploading the single line tripping details along with DR (comtrade files), EL and other relevant files for all trippings of August 2017 onwards. Otherwise, it will be considered as violation of compliance of clause 5.2(r) & 5.9 of IEGC. Members may discuss. Deliberation in the meeting Members explained the tripping incidences. Updated status is enclosed at Annexure-D1. PCC advised all the constituents to upload the details along with DR and EL in PDMS on-line portal

59th PCC Minutes 26

Item No D.2 Any other issues. 1. Preparation of reliability standards for protection system for Indian Power System--NPC CEA vide letter dated 12th September 2017 informed that CERC in its Order dated 05.08.2015 wrt Petition No. 009/SM/2015 in the matter of following up actions on the recommendations of CAC Sub-Committee on Congestion in Transmission, directed National Reliability Council for Electricity (NRCE) to prepare Standards for Protection System. NRCE in its 6th meeting held on 17th March 2016 had formed a Subgroup for Preparation of the Reliability Standards for Protection system and Communication system for Indian Power System. Five meetings were held by the Subgroup. A draft of Reliability Standards for Protection System for Indian Power System has been prepared. It is requested to furnish the comments from Eastern Region constituents for finalizing the standard. Deliberation in the meeting It was informed that draft copy of Reliability Standards for Protection System for Indian Power System is enclosed at Annexure-D2 and also available at ERPC website. PCC advised all the constituents go through the draft and send their comments to erpcprotection@gmail.com with a copy to mserpc-power@nic.in.

Meeting ended with vote of thanks to the chair.

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

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Tripping Analysis on disturbance at Sasaram 220 KV

12th August’17

Annexure-B4

Pre fault condition• 220 KV Bus coupler was in open condition for

overhauling of pneumatic drive of its CGL make CircuitBreaker as air leakage observed in safety valve.

• At the time of opening of Bus Coupler, the feederwas connected as per following arrangement:

220 kv Main Bus-11. 315 MVA ICT-22. Shahupuri3. Ara

220 kv Main Bus-21. 500 MVA ICT-12. Nadokhar3. Dehri

SLD OF 220 KV PUSAULI

Fault Incident description

• S/D of 220 kV Bus-1 approved for attending problem of Bus-1isolators of both ICTs.

• As bus coupler was already under S/D, for isolation of 220 kVBus-1, it was planned that all the Main Bus-2 isolators ofShahupuri, Ara, ICT-2 (connected with Bus-1) will beclosed first and then their Bus-1 isolators will be openedone by one.

• First of all ICT-2 Main Bus-2 isolator (389B) was closed.This was a silent closing. However after closing of the saidisolator, which is mechanical coupled (on same IPS tube)with already closed isolator (389A), Flash started appearing inR & B contact of the mentioned isolator 389A.

Fault Incident description

• It grew very rapidly and flame/ flash was observedbetween corona disc of male and female contacts

• 220 KV CB of ICT-2 was opened at 14:49:09 Hrs butflash/ flame continues

• At 14:50:30 Hrs ICT-2 & at 14:50:31 ICT-1 tripped. ICT-1 tripped on over current protection in B-Ph and ICT-2tripped on Differential protection in same phase andflashover stopped.

Analysis of tripping event• During closing of Main Bus-2 isolator 389B, the main bus-

1 isolator 389 A may have experienced jerk due tomechanically coupling with IPS tube, resulting into losingof isolator female contact spring tip.

• After closing of Iso 389B, 500MVA ICT-I also getconnection with Bus-1, which was initially feeded onlybus-2 and hence flow of current might have increased inthe isolator 389A for supplying of power to Shahupuri andAra

• Due to the mentioned reasons flashing started appearingin R & B contact of the mentioned isolator 389A of ICT-2bay.

Analysis of tripping event

• It grow very rapidly and flame/ flash was observedbetween corona disc of male and female contacts.

• Due to this heavy flash, Pitting of conductor between220 KV LA of ICT-2 and suspension insulator from thegantry has also been observed (which is nearby the389A Isolator), which caused tripping of ICT-2 ondifferential protection.

• Further ICT-1 tripped on O/C protection in B-phaseand flash in isolators stopped.

Corrective measures taken

• Damaged Isolator arms / finger contacts replaced.

• Feeder connectivity rearranged as 500MVA ICT-1, Sahupuri & Ara on Bus-1 and 315MVA ICT-2, Dehri & Nadokhar on Bus-2.

LINE

Teesta Rangpo Binaguri

37.5 115

12

Teesta V

- III

6x200MW

DIKCHU

47.5 KM7 115 KM7

16.3 KM

2x50MW

12 KM7

Annexure-B8

TRIPPING ANALYSIS REPORT (PCC-59:B.8)DATE & TIME : 04/08/2017 , 13:46:27 HRS FEEDER / UNIT : 400kV Teesta III – Dikchu Line(Line-2)Preconditions –1) Line-1 and Line-2 in charged condition and Plant running at 890MW

Tripping -1) Teesta III – Dikchu Ckt (Line-2) line tripped on Earth fault IDMT protection operated by the cable relayObservation –Teesta III – Dikchu Ckt (Line-2):

Cable Relay (7SD610) : Backup Earth OC IDMT trip, Faulted phase BN , Current observed IR- 10A , IY- 70A, IB- 1600A, Trip time- 2345ms

Main1 backup directional relay (7SJ621) : Directional time OC Earth IDMT pickup, Faulted phase BN, Current observed IR- 20A, IY- 70A, IB- 1600A, pickup time-2156ms

P442 Relay (Main-2 distance relay): Earth fault IN-1 pickup, Faulted phase BN ,Current observed IR- 07A , IY- 71A,IB- 1623A , IN- 1550A , Voltage observed VRN-237kV, VYN- 242kV, VBN- 234kV, VN- 232KV

Setting : In all the relays Earth OC IDMT setting –I > 0.1A

TMS -0.7

Teesta III- Dikchu backup cable relay(7SD610, Non-directional relay)

Cable relay tripping time (13:46:27.491+ 2345ms) –

13:46:29.836 Hrs

Action taken-1) As the fault current was very less, so one attempt taken to charge the line

and line charged successfully.

Analysis –LINE 2- As per DR & ER of Teesta III – Dikchu line, backup Earth OC tripping initiated by Cable relay and in other relays earth fault pickup observed.

In the cable relay : fault started at 13:46:27.491 Hrs and continuous fault current observed for 2345ms, resulting tripping.

In the main1 backup directional relay(7SJ621) : Fault started at 13:46:27.676 Hrs(after 185 ms of cable relay initiated), and resetted after 2156ms (as line tripped)

In the main2 distance relay : Earth fault pickup ON and OFF two times observed

As the fault current is very less and very less dip of fault voltage, so distance tripping not Initiated.

The fault may be due to trees closer to B-phase

This tripping is similar to tripping on 16/07/2017

TRIPPING ANALYSIS REPORT DATE & TIME : 16/08/2017 , 12:18:17 HRS FEEDER / UNIT : 400kV Teesta III – Rangpo Line(Line-1)Preconditions –1) Line-1 and Line-2 in charged condition

Tripping -1) Teesta III – Rangpo line tripped on Zone-1 protection

Observation –Teesta III – Rangpoo Ckt (Line-1):

Main-1 Relay : Faulted phase BN, carrier send, Carrier Receive, Z1, IR- 1.8kA,IY-0.11kA, IB-6.2kA

Main-2 Relay : Faulted phase BN, Z1, Carrier send, Carrier Receive, Fault location 18.41km, IR-1819A, IY- 238A, IB- 6766A, IN- 8444A

Cable Relay (7SD610) : Backup Earth OC pickup, Faulted phase BN

Main1 backup directional relay(7SJ621) : Directional time OC Earth pickup , Faulted phase BN

Setting Zone 1 : Impedance - 80% of protected lineTime - Instantaneous

Annexure-B9

Action taken-1) Problem attended by transmission team. Teesta-III Rangpo line charged at

11:34Hrs, dated 18.08.2017

Analysis –Teesta-III Rangpoo Ckt (LINE 1): As transmission team, one conductor of B-phase out of four conductors of Teesta III- Rangpo line snapped at near tower no-23

Action to be taken-1) Auto-reclose will be implemented from Teesta-III end by sept.2017 end

Annexure-B12

FIRST HAND TRIP REPORT Name of the S/S: A Trip Report No:

Date & Time: 19.04.15 Time: 17: 00 hrs 1. Name of the Tripped Line/ICT/Reactor/Bus : 400KV S/C (A- B) line 2 Tripping date & time : 19.04.2015 at 14:13 hrs 3. Status of Auto-reclosure (In case of Single phase to ground fault of transient nature) : A/R successful but fault persists 4 Reason for non-operation/Unsuccessful : N.A Auto-reclosure .

5 System condition prior to tripping : 14: 00 hrs Voltage (KV) Frequency (Hz) Load of the tripped line in MW/MVAR

412 50.16 1. 400KV S/C (A- B) line -377/+35

6. Relay flags:

Local End Remote end 1. 400KV A - B line Relay Flag: MICOM P442 (Main-I), Z1 Trip REL 670 (Main-II), 86C (C-Phase) ,Dist.: C-E, 82.24KM

1. Main-I & Main-II

7. Sequence of Normalization : (Date & Time to be mentioned) a. 19.04.15 14:53 hrs A-B line extended from B end.

b. 19.04.15 14:54 hrs A-B line synchronized at A end

8. Cause of Tripping: Earth Fault (C-Phase to E) in system 9. Remedial action taken / required: Line patrolling is going on. Signature: Shift-In-Charge

22/09/2017

1

TRIPPING ANALYSIS REPORTDATE & TIME : 16/07/2017 , 00:29:55 HRS FEEDER / UNIT : 400kV Teesta III – Dikchu Line (Line-2)Preconditions –1) Line-1 and Line-2 in charged condition

Tripping -1) Teesta III – Dikchu line tripped on Earth fault IDMT protection operated by the cable protection relayObservation –Line-2: Cable Relay (7SD610) : Backup E/F OC IDMT trip, Faulted phase BN , Current observed IR- 10A , IY- 60A,IB- 1100A, trip time- 2850ms

Main1 backup directional relay (7SJ621) : Directional time OC Earth IDMT pickup , Faulted phase BN , Current observed IR- 30A , IY- 50A, IB- 1500A, pickup time-1337ms

P442 Relay (Main2 distance relay): Earth fault IN 1 pickup, Faulted phase BN ,Current observed IR- 10A , IY- 55A,IB- 1100A , IN- 1058A , Voltage observed VRN-235kV, VYN- 238kV, VBN- 232kV, VN- 163KV

Setting : In all the relays Earth OC IDMT setting –I > 0.1A

TMS -0.7

Annexure-C1

Teesta III- Dikchu backup cable relay(7SD610, Non-directional relay)

Cable relay tripping time (00:29:53.142 + 2850ms) –

00:29:55.992 Hrs

22/09/2017

2

Action taken-1) As the fault current was very less , so one attempt taken to charge the line

and line charged successfully.

Analysis –LINE 2- As per DR & ER of Teesta III – Dikchu line, backup Earth OC tripping initiated by Cable relay and in other relays earth fault pickup observed.

In the cable relay : fault started at 00:29:53.142 Hrs and continuous fault current observed for 2.85sec, resulting tripping.

In the main1 backup directional relay (7SJ621) : Fault started at 00:29:54.609 Hrs(after 1467 ms of cable relay initiated) , and resettled after 1377ms (as line tripped)

In the main2 distance relay : Earth fault pickup ON and OFF three times observed

Due to high resistance fault the fault current was not very high and very less dip in fault voltage found, so distance tripping not Initiated.

The fault may be due to trees closer to B-phase.

TRIPPING ANALYSIS REPORTDATE & TIME : 24/07/2017 , 15:56 Hrs & 19:11 HrsFEEDER / UNIT : Unit – 1,2,3 &4Preconditions –1) Line-1 and Line-2 in charged condition2) Unit-1, 2, 4 was on Bus-II and Unit-3 was on Bus-I3) Unit-5 was under shutdown due to Rotor Earth fault

Tripping -1) Unit-1, 2 & 4 gone to No-load operation and 50MW load reduced in Unit-3, due

to SPS Code-2

Observation –At 15:56 Hrs : Unit-5 was under shutdown due to Rotor Earth fault checking. So after proper cleaning of Rotor slipring and taking IR value of Rotor, we started Unit-5.At the time Unit-5 Field flashing, Unit-5 tripped on Rotor EF and other units gone to No-load operation, due to SPS code-2 activation signal at SCADA.

After informing ERLDC , we synchronized the units again.At 19:11 hrs : We started unit-5 again and at the time of initial field flashing ON command, the above signal again appeared ie SPS code-2 signal high and units tripped.

22/09/2017

3

Action taken-

1) We checked and found that there was week insulation in LT Bus trunking,which is connected to Excitation transformer to Excitation panel. Now wedisconnected to this Bus-Trunking and connected by cables and alsoswitched OFF the DC field flashing.

2) Now Unit-5 is being started only on AC field flashing, which assure that thisproblem will not trip the system again.

3) Soft logic of previous SPS-2 signal removed.

Analysis:The previously configuration for SPS code-2 was as follows:The units connected to 400kV Bus-2 will go to no-load operation and 50MW loadshould reduce on the unit connected to Bus-1.As per the logic above automatic action activated on activation of SPS-2 signal.

At present configuration given by ERLDC, SPS code-2 is not in circuit at Teesta-IIIend and the hardwire connection was already removed between PLCC & trippingcircuit, but in soft logic (SCADA) it was present, which cause the tripping of Units.

Previously field flashing was done by DC field flashing, it was observed that at thetime of field flashing ON command in Unit-5, there was dip of DC voltage in DCDB,due to which low DC voltage occurs, resulting in activation of SPS code-2 signal.

SPS SCHEME

X-303

13

14

Line-1 PLCCSpeech+Prot -1

X-303

13

14

Line-1 PLCCSpeech+Prot -2

X01

342

343

SPS - 1

SPS - 2

+ve

+ve

Line-1 Protection

Panel

BC Bay Controlle

r

K116 Relay

JOINT CONTROL

BOARD

SCADA

CB TRIP

Modified Scheme

K117 RelayDis-connected

Connected

SCADA for soft logic

22/09/2017

4

TRIPPING ANALYSIS REPORTDATE & TIME : 27/07/2017 , 10:08 HrsFEEDER / UNIT : 400kV Teesta III – Rangpo Ckt (Line-1)Preconditions –1) Line-1 and Line-2 in charged condition

Tripping -1) 400kV Teesta III – Rangpo Ckt (Line-1) tripped due to SPS code-2 (Rangpoo end)

Observation –At 10:08 Hrs : 400kV Rangpo-Binagudi Ckt-2 tripped due to BN fault. After tripping of line, power flow in 400kV Rangpo-Binagudi ckt-1 became more than 850 MW, resulting initiation of SPS code-1.At Teesta-III . SPS code-1 received upto PLCC (Rx increased). But it missed between the PLCC panel to Bus-coupler panel. Resulting Units didn’t trip.

As per present SPS code-2 scheme activated at Rangpoo end and trip the Teesta III- Rangpo circuit breaker at Rangpo end.

Action taken-1) The PLCC cards checked and properly cleaned.2) During checking at PLCC panel we found at X303-14 +Ve voltage

missing, we rectify the problem.3) SPS mock test done successfully by shorting the terminal X303- 13

& 14 from PLCC panel, after rectifying the problem as above.

Analysis –At PLCC panel there was some problem so SPS code-1 signal was not transferred from PLCC panel to Bus-coupler tripping circuit and in SCADA. Therefore line tripped on SPS code-2 activation at Rangpoo s/s (after 500ms delay), as per present scheme.

After this incident two times SPS code-1 received and Bus coupler operated successfully as follows:

1. 19/08/2017 at 12:46hrs 2. 19/08/2017 at 13:10hrs

Action to be taken-Two channels may be used for transmission of SPS signal from Rangpoo to Teesta-III

22/09/2017

5

SPS SCHEME

X-303

13

14

Line-1 PLCCSpeech+Prot -1

X-303

13

14

Line-1 PLCCSpeech+Prot -2

X01

342

343

SPS - 1

SPS - 1

+ve

+ve

Line-1 Protection

Panel

BC Bay Controlle

r

K116 Relay

JOINT CONTROL

BOARD

SCADA

CB TRIP

Modified scheme

K117 RelayDis-connected

Connected

SCADA for soft logic

Proposed scheme

D

D

SPS SCHEME

X-303

13

14

Line-1 PLCCSpeech+Prot -1

X-303

13

14

Line-1 PLCCSpeech+Prot -2

X01

342

343

SPS - 1

SPS - 1

+ve

+ve

Line-1 Protection

Panel

BC Bay Controlle

r

K116 Relay

JOINT CONTROL

BOARD

SCADA

CB TRIP

Proposed scheme

D

D

Master Trip Relay of BC

CB

R-ph trip ckt 1 &2Y-ph trip ckt 1 & 2

B-ph trip ckt 1 & 2

22/09/2017

6

SPS-1:On 19/08/2017 at 12:46 Hrs & 13:10Hrs SPS-1 signal received and Load reduced accordingly by tripping of Bus-coupler breaker & Units

ITEM NO. C.1:

Repeated disturbances at 400kV Teesta-III, Dikchu and Rangpo on at 00:30 hrs on 16-07-2017, 15:56 hrs & 19:11 hrs on 24-07-2017 and 10:08 hrs on 27- 07-2017

In addition to above Teesta-III to Dikchu Ckt tripped on 13:46hrs on 04-08-2017 and again on 11:54Hrs & 12:27Hrs on 28thAug.2017 and found some trees creating fault during windy weather.

Finally trees trimmed by Transmission Team at near Tower No-23 and line charged at 16:46hrs on 28th Aug.2017

Tripping Analysis of 765kV Dharamjaigarh-Ranchi II

15th June’17

Annexure-C4

Fault Incident description• 765kV Dharamjaigarh-Jabalpur Ckt-3 issued trip command on

R-Y fault.

• The Main CB tripped, however, none of the poles of Tie CB tripped, thus all the connected lines tripped on Zone-3 from remote end.

• TC-1, TC-2 and LBB relay faulty alarms had appeared.

• The Close indication lamp in the breaker MB had failed(burnt)which had caused a short circuit. The fault resulted in the DC fusefailure for CB TC-1. The DC changeover relay routed DC-2 supply tothe Changeover DC thereby feeding the faulty indication lamp andled to failure of DC-2 as well.

• The Tie LBB relay was also fed through the same DC-2 fuse, thus,the failure of this fuse also resulted in the powering off of the tieLBB relay.

Tripping of Ranchi-Dharamjaygarh Ckt-II after approx 3 minutes

• For Circuit-1 the fault impedance was just on theboundary of Zone-3. The tripping occurred after 1sec ofstart of Z3 element. Thus the tripping was found correct.

• The Circuit-1 is 301km and Circuit-2 is 353km. Althoughthe fault was just on the boundary of Zone-3 for Circuit-1,it was out of Zone-3 for Circuit-2 due to lower Z-3 setting.

• The Circuit-2 remained connected and was feeding the 9nos 110 MVAr reactor banks at Dharmjaigarh. Thisreduced the balanced line voltage to approx. 500kV (Ph-Ph), in all three phases at Ranchi end. The line wasfeeding approx 2000A balanced current in all the threephases.

Tripping of Ranchi-DharamjaygarhCkt-II after approx 3 minutes

• Thus it can be seen that the fault was not present forcomplete duration of 3 minutes but was intermittent innature.

• Intermittently the fault appeared in the Zone-3 of thedistance relay at 4 instances. However, the fault remainedin Zone-3 for 100-500ms duration in all the 4 instances,due to which the Zone-3 did not trip.

• After approx 3 minutes, the fault re-appeared in Zone-3and persisted for 1 second, resulting in the tripping of theRanchi-Dharamjaigarh Circuit-2.

Corrective measures at New Ranchi

• Zone-3 settings of NRNC-DMJ-2 line has been modified

LINE NAME From End UtilityTO End

UtilityTRIP DATE TRIP TIME

RESTORATION

DATE

RESTORA

TION

TIME

Relay Indication

LOCAL END

Relay Indication

REMOTE ENDReason

Fault Clearance

time in msec Auto Recloser status

DR/EL RECEIVED

FROM LOCAL

END

DR/EL

RECEIVED

FROM

REMOTE END

Remarks

220KV PUSAULI-DEHRI-I PG BSPTCL 05-08-2017 11:27 05-08-2017 12:26 Tripped from PUSAULI end only E/F, Ir=560 A 300 msecNo autoreclose operation

observed in PMU dataYes

back up protection

operated at Dehri

132KV MUZAFFARPUR-DHALKEBAR-

IPG Nepal 11-08-2017 3:41 11-08-2017 4:13 Y_N, Z2, 1.288KA, 155.1 KM From Muzaffarpur Y-N FAULT 150 msec As per PMU Y-B fault

132KV MUZAFFARPUR-DHALKEBAR-I PG Nepal 11-08-2017 4:16 11-08-2017 4:37 Y_N, Z2, 1.288KA, 155.1KM From Muzaffarpur Y-N FAULT 1100 msec As per PMU Y-B fault

400KV TEESTA-III-RANGPO-I Teesta-III PG 16-08-2017 12:18 16-08-2017 12:41Tripped on b_n fault - charging attempted at

12:41 hrs failed on SOTFB-N FAULT 480 msec Unsuccessful Yes

220KV TARKERA-ROURKELA-I OPTCL PG 07-08-2017 12:36 07-08-2017 12:49 Z1, RN, 9.9KM From Tarkera, 8.29 KA R-N FAULT 240 msecNo autoreclose operation

observed in PMU data

400KV BINAGURI-ALIPURDUAR-II PG PG 21-08-2017 10:55 21-08-2017 11:51Alipurduar: B_N fault, F.D.:

93.5 KM, F.C.: 4.507 kAB-N FAULT 700 msec

No autoreclose operation

observed in PMU data

220KV STPS(WBSEB)-CHANDIL-I WB JUSNL 21-08-2017 13:46 21-08-2017 13:58 R_N Fault, Zone IISuccessful A/R from

Chandil endR_N Fault 600 msec

No autoreclose operation

observed in PMU dataYes

A/R not working

properly and Zone 2

time 600 ms at STPS,

WBPDCL was advised

to review.

220KV STPS(WBSEB)-CHANDIL-I WBSETCL JUSNL 23-08-2017 10:54 23-08-2017 15:35 Z2, BN, 97.24KM From STPS, 1.30KA ZI, BN B_N Fault 525 msecNo autoreclose operation

observed in PMU dataYes

Multiple tripping at

the same time

220KV CHANDIL-RAMCHANDRAPUR-SC JUSNL JUSNL 23-08-2017 10:54 23-08-2017 11:12 Tripped from Ramchandrapur onlyZ2, BN, 64.76KM From

Ramchandrapur, 2.087KAB_N Fault 525 msec

No autoreclose operation

observed in PMU dataYes

Multiple tripping at

the same time

220KV PUSAULI-DEHRI-I PG BSPTCL 24-08-2017 14:37 24-08-2017 15:23 R-N , 178 KM, 1.1 KA,Z3 R_N Fault 800 msecNo autoreclose operation

observed in PMU dataFault in down stream

400KV BINAGURI-MALBASE-III PG Bhutan 26-08-2017 1:36 26-08-2017 2:10B-N/109.7KM FRM BINAGURI, Fault current

3.16 kaB-N FAULT 600 msec

No autoreclose operation

observed in PMU data

A/R not available at

Malbase

400KV NEW PURNEA-BIHARSARIFF-II PG PG 02-08-2017 14:05 02-08-2017 14:28 A/R unsuccessful at new purnea

B_N;201.2 km from

biharshariff,2.37 KA.A/R

successful at BSF

B-N FAULT < 100No autoreclose operation

observed in PMU data

A/R under off

condition. Now in

service

400KV KOLAGHAT-KHARAGPUR-II WB WB 04-08-2017 11:36 04-08-2017 12:01 Kgp: Z1, B-ph,Dist=55.2km, Ifault=3.415KA,

Ktpp: Z1, B-

ph,Dist=26.69km, I fault=

7.255KA

B-N FAULT < 100No autoreclose operation

observed in PMU data

PLCC problem. The

problem has been

rectified.

400KV NEW PPSP-ARAMBAGH-I WB WB 04-08-2017 19:06 04-08-2017 19:30AT ARAMBAG:R-N

FAULT,32.9 KM.R-N FAULT < 100

No autoreclose operation

observed in PMU data

220KV PUSAULI-SAHUPURI(UP)-I PG NR 05-08-2017 11:02 05-08-2017 12:27 RN, 18.09KM From PUSAULI, 5.539KA R-N FAULT < 100No autoreclose operation

observed in PMU data

765KV JHARSUGUDA-DARLIPALI-II PG NTPC 14-08-2017 14:43 14-08-2017 15:45 YN,21KM From Jharsuguda, Iy=11.7KA Y-N FAULT

400KV BAHARAMPUR-BHERAMARA-I PG Bangladesh 01-08-2017 14:58 02-08-2017 19:51Y_B fault;Iy=1.3 KA,Ib=5.57 KA,60.67 km from

behrampur;tripped on reattempting at 15:48

cONDUCTOR SNAP AT LOC

79 IN BORDER AREA

Y-B FAULT,

CONDUCTOR SNAP< 100 Unsuccessful Yes

As per PMU B_N

Fault

220KV NEW MELLI-JORETHANG-I PG Jorthang 01-08-2017 19:40 01-08-2017 19:56 tripped at jorethang end only --

400KV BINAGURI-NEW PURNEA-II PG PG 02-08-2017 23:59 03-08-2017 3:16 OVER VOLTAGE AT STAGE-I OVER VOLTAGE -- --

220KV MAITHON-DUMKA-I PG JUSNL 04-08-2017 11:39 04-08-2017 12:23DT RECEIVED AT MAITHON.NO FAULR IN PMU

SEEN

CKT REMAINED CLOSED AT

DUMKA--

400KV ANGUL-JITPL-II PG JITPL 04-08-2017 19:17 05-08-2017 11:19 DT RECEIVED AT ANGULDT RECEIVED AT

ANGUL--

400KV BINAGURI-KISHANGANJ-I PG PG 05-08-2017 10:34 05-08-2017 10:42 DT Recieved at BinaguriTripped from Binaguri end

only

DT Recieved at

Binaguri--

400KV BINAGURI-KISHANGANJ-I PG PG 05-08-2017 11:11 05-08-2017 11:28 DT Recieved at BinaguriTripped from Binaguri end

only

DT Recieved at

Binaguri--

400KV NEW PURNEA-BIHARSARIFF-II PG P