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TRANSCRIPT
Minutes
of
78th PCC Meeting
Date: 08.05.2019
Eastern Regional Power Committee
14, Golf Club Road, Tollygunge
Kolkata: 700 033
EASTERN REGIONAL POWER COMMITTEE
MINUTES OF 78TH PROTECTION SUB-COMMITTEE MEETING HELD AT ERPC, KOLKATA ON 22.04.2019 (MONDAY) AT 11:00 HOURS
List of participants is enclosed at Annexure-A.
PART – A
ITEM NO. A.1: Confirmation of minutes of 77th Protection sub-Committee Meeting held on 26th March, 2019 at ERPC, Kolkata.
The minutes of 77th Protection Sub-Committee meeting held on 26.03.19 circulated vide letter dated 10.04.19. Members may confirm the minutes of 77th PCC meeting. Deliberation in the meeting ERLDC vide mail dated 22nd April 2019 has requested for addendum in the deliberation of item B1. “ERLDC informed that puncturing of insulator from bottom side i.e. back flash over generally occurs during high tower footage resistance. Similar phenomenon had been observed during the disturbance at Koderma on 30th January 2018 at 10:46 hrs where voltage rise had been occurred in the healthy phases for a single phase to ground fault. ERLDC added that protection audit may be conducted at Koderma, BTPS, CTPS and Ramgarh to check these issues.” Members confirmed the minutes of 77th PCC with above addendum.
PART – B
ANALYSIS & DISCUSSION ON GRID INCIDENCES OCCURRED IN MARCH, 2019 ITEM NO. B.1: Disturbance at 400 kV Lapanga(OPTCL) S/s
1. On 14.03.2019 at 13:39 Hrs
At 13:39 hrs, 400 kV Lapanga – OPGC D/C tripped from Lapanga end due to R-Y phase to phase fault in circuit-II. At the same time, B/B protection operated for 400 kV bus-I at Lapanga resulting tripping of main CB of 400 kV Lapanga – Meramundali – II, 400 kV Lapanga – SEL – I and tie CB of 400/220 kV ICT – I. 400 kV SEL Jharsuguda D/C tripped from Jharsuguda end due to DT receipt. Detail report is attached in Annexure-B1.1. As per PMU data, there were faults in R & Y phases and fault clearing time is more than 100 ms. Relay indications are as follows:
Name of the elements End 1 Relay Indication End 2 Relay Indication
400 kV Lapanga – OPGC D/C
Circuit I: Z-III, 42.5 km, 13.5 kA, 12.84 kA, 0.09kA
Yet to be received
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Circuit II: Z-I, 0.9 km 36.166 kA, 31. 166 kA, 0.04 kA (fault clearing > 100 ms)
400 kV SEL – Jharsuguda D/C
Yet to be received
DT received
Load Loss: Nil OPTCL may explain. Deliberation in the meeting OPTCL explained the disturbance with a presentation. The presentation is enclosed at Annexure B.1.1. OPTCL explained that there was a L-L fault in 400 kV Lapanga – OPGC-II which got cleared from Lapanga end on zone-I distance protection. At the same time, busbar protection operated for main bus-I at Lapanga end leading to tripping of all the elements connected to bus-I. OPTCL informed that during the thorough inspection it was found that the logic of LBB relay was wrongly configured which leads to mal operation of the relay and initiation of busbar protection relay. OPTCL added that they had referred the issue to OEM for further consultation. PCC could not conclude the disturbance and advised OPTCL to submit the DR of LBB relay to ERPC and ERLDC for further analysis. PCC also advised OPTCL to submit the OEM recommendation on this issue. PCC advised SLDC, Odisha to collect and submit the details of tripping at SEL & OPGC end to ERLDC/ERPC at the earliest. Regarding tripping of 400 kV Lapanga – OPGC-I, OPTCL informed that the circuit got tripped on STUB protection. They added that the tripping was due to the wrong configuration of PSL logic. They have rectified the logic after this incident.
2. On 15.03.2019 at 11:59 Hrs
At 11:59 hrs 400 kV Lapanga-Meramundali D/C tripped from both ends on Y-N fault due to heavy sparking of line isolator of 400 kV Lapanga Meramundali - II. At the same time B/B protection of Bus II operated resulted tripping of feeders connected to Bus-II.(As Bus I was not in service, 400 kV level got completely black out).
Relay indications are as follows:
Name of the elements End 1 Relay Indication End 2 Relay Indication
400 kV Lapanga – Meramundali D/C
Circuit I: Y-N, Z-I, 16 kA
CKT I: Y-N, Z-2, DTT TRIPPED, Iy- 1.73 KA, DIST- 286.1 KM CKT II: Yph-N, ZONE-2 , 214.1KM, Fault Current= 2.36KA
400 kV Lapanga – SEL D/C 400 kV Lapanga – OPGC D/C 400/220 kV ICT – I at Lapanga
B/B protection at Lapanga
Yet to be received
Load Loss: Nil
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OPTCL may explain. Deliberation in the meeting OPTCL explained that due to heavy lightening in the switchyard the line isolator contacts of 400 kV Lapanga-Meramundali – II got burned resulting into a fault. The distance protection of both the end operated correctly and cleared the fault as per their zone settings. Lapanga-Meramundalicircuit-I also got tripped from Meramundali end in zone-II of distance protection. At the same time, the busbar differential relay operated for Bus-II at Lapanga and tripped all the elements connected to it. Since Bus-I was not in service due to previous disturbance on 14.03.2019, total black out occurred at 400 kV Lapanga. OPTCL informed that during checking of the relay it was found that the settings of busbar differential relay was quiet low (100 mA). They have changed the settings to 200 mA and referred the issue to OEM for review of the settings. PCC opined that the damage of equipment insulators within the switchyard due to lightning is not desirable and advised OPTCL to check the lightning mast coverage area and earthing of the substation properly. Regarding maloperation of Busbar protection, PCC advised OPTCL to check for the CT polarity connections in the busbar relay and advised to review the busbar settings in consultation with OEM. PCC also advised OPTCL to configure the DR settings properly. ITEM NO. B.2: Disturbance at 400 kV Binaguri S/s on 27.03.2019 at 12:42 Hrs. During charging attempt of 400 kV Binaguri – Alipurduar – II from Binaguri end, it got tripped on B-N fault after one second. At the same time, LBB relay of main bay of 400 kV New Purnea – I (connected to main bus-I at Binaguri end ) operated resulting tripping of all breakers connected to 400 kV main bus-I. Load Loss: Nil Powergrid may explain. Deliberation in the meeting Powergrid explained the disturbance with a presentation. The presentation is enclosed at Annexure-B3. Powergrid informed that during the charging of 400 kV Binaguri – Alipurduar – II from Binaguri end, LBB relay operated for the main bay of 400 kV Binaguri-New Purnea – I and tripped all the elements connected to 400 kV main bus-I. Powergrid added that, after one second of charging the 400 kV Binaguri – Alipurduar – II, it got tripped on B-N fault in zone-I of distance protection from Binaguri end. Powergrid further informed that during inspection it was found that the hardware configuration was wrongly done for the LBB relay which caused mal operation of the relay. They have corrected the hardware configuration after the disturbance thereafter the relay was tested and put into operation. ITEM NO. B.3: Disturbance at 400 kV Berhampur S/s on 31.03.2019 at 15:21 Hrs.
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At 15:21 Hrs, 400 kV Berhampur – Bheramera D/C tripped due to B-N fault followed by blocking of both poles at Bheramera back to back HVDC converter station. Due to loss of supply of 850 MW through HVDC Bheramara Bipole, the Bangladesh grid frequency dropped to 48.87 Hz from 50.8 Hz. Detail report is attached at Annexure-B3. In PMU data, fault has been observed in B phase along with unsuccessful A/R attempt.
Powergrid may explain. Deliberation in the meeting Powergrid informed that there were multiple faults occurred in 400 kV Berhampur – Bheramera D/C line during the disturbance. Initially there was an L-G fault in B-phase of both the lines of 400 kV Berhampur – Bheramera D/C line. The Autorecloser for both the circuits was attempted from Berhampur end. The autorecloser for 400 kV Berhampur – Bheramera line-I was unsuccessful due to persistent fault in B-phase and the line got tripped subsequently. 400 kV Berhampur – Bheramera line-II got tripped due to a second fault (R-Y-G) during the reclaim time. ITEM NO. B.4: Repeated tripping of 400 kV Ranchi-RTPS –II in the month of March, 2019.
400 KV Ranchi-RTPS-II tripped seven times on single line to ground fault in the month of March, 2019. The list is shown below.
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S.NO LINE NAMETRIP
DATE
TRIP
TIME
RESTORATI
ON DATE
RESTORA
TION
TIME
Reason
Fault
Clearance
time in msec
Auto Recloser status
1 400KV RANCHI-RAGHUNATHPUR-II 11-03-19 0:41 11-03-19 1:14 Y-N Fault < 100 msecA/R successful from
Ranchi only
2 400KV RANCHI-RAGHUNATHPUR-II 14-03-19 16:21 14-03-19 17:29 R-N Fault < 100 msecA/R attempted but
unsuccessful
3 400KV RANCHI-RAGHUNATHPUR-II 15-03-19 16:56 15-03-19 19:12 R-N Fault < 100 msecA/R attempted but
unsuccessful
4 400KV RANCHI-RAGHUNATHPUR-II 22-03-19 14:22 22-03-19 15:14 R-N Fault < 100 msecA/R successful, tripped
in reclaim time
5 400KV RANCHI-RAGHUNATHPUR-II 25-03-19 21:02 25-03-19 21:45 Y-N Fault < 100 msecSeems A/R successful
from one end only
6 400KV RANCHI-RAGHUNATHPUR-II 26-03-19 11:08 26-03-19 18:14 R-N Fault < 100 msecA/R successful, tripped
in reclaim time
7 400KV RANCHI-RAGHUNATHPUR-II 31-03-19 16:29 31-03-19 17:18 R-N Fault < 100 msecA/R successful, tripped
in reclaim time DVC and Powergrid may explain. Deliberation in the meeting DVC informed that the repeated trippings were occurred due to the clearance issue between the earth wire and R-phase conductor of 400 KV Ranchi-RTPS-II line. They added that the location was identified and the clearance issue was rectified on 13th April, 2019. After that no such tripping were reported in the line. ITEM NO. B.5: Repeated tripping of 220 kV Farakka-Lalmatia S/C in the month of March,
2019. 220 KV Farakka-Lalmatia-S/C tripped six times in the month of March, 2019.
S.NO LINE NAME TRIP DATETRIP
TIME
RESTORATION
DATE
RESTOR
ATION
TIME
Relay Indication
LOCAL END
Relay
Indication
REMOTE
END
Reason
1 220KV FSTPP-LALMATIA-SC 09-03-19 10:49 09-03-19 18:40 B-N, 2.2 kA, 63 km B-N Fault
2 220KV FSTPP-LALMATIA-SC 11-03-19 10:38 11-03-19 18:54 B-N, 64 KMS DID NOT TRIP
at LalmatiaB-N Fault
3 220KV FSTPP-LALMATIA-SC 12-03-19 9:58 13-03-19 17:21 B_N, 2.154 kA, 64 KM
4 220KV FSTPP-LALMATIA-SC 14-03-19 11:55 14-03-19 17:31 LBB operated
LBB
operated at
Lalmatia
5 220KV FSTPP-LALMATIA-SC 15-03-19 19:05 15-03-19 20:35 O/C E/F O/C E/F
6220KV FSTPP-LALMATIA-SC
28-03-1913:05
28-03-19 14:50B_N Fault, 61.25 KM,
0.38 kA B-N Fault
NTPC & JUSNL may explain. Deliberation in the meeting JUSNL informed that the above trippings were due to the clearance issue of 11 kV line below the 220 kV Farakka-Lalmatia line. They informed that the 11 kV line has been shifted to other location on 13th April 2019. After that no trippings have been reported.
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ITEM NO. B.6: Tripping Incidences in the month of March, 2019. Other tripping incidences occurred in the month of March 2019 which needs explanation from constituents of either of the end is given in Annexure-B6. 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. In 74th PCC, all the constituents were requested to submit the disturbance report along with DR through the new version of on-line portal which was implemented from 01st Jan. 2019. Members may discuss. Deliberation in the meeting Members explained the tripping incidences. Updated status is enclosed at Annexure-B6. PCC advised all the concern constituents to take necessary corrective actions to resolve the issues.
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PART- C:: OTHER ITEMS
ITEM NO. C.1: Islanding Scheme at Kanti TPS- KBUNL In 68th PCC Meeting, it was decided that the islanding of Kanti TPS would be implemented with the following scheme:
1. Stage II units (2x195 MW) of Kanti TPS will be islanded with station load of 40 MW and
radial load of 150 MW (approx.) of 220kV Kanti TPS-Gopalganj D/C line.
2. Once the grid frequency falls to 48.2 Hz, the PLC at Kanti TPS would initiate the islanding
process with 500 ms time delay.
Members may discuss.
Deliberation in the meeting
NTPC suggested that a step wise islanding scheme may be planned considering different grid
conditions and unit availability at Kanti TPS.
PCC advised NTPC to prepare a draft plan and submit to ERPC and ERLDC for detailed
discussion in next PCC Meeting.
NTPC informed that construction of bays of 220kV Bus Sectionalizer at 220kV Kanti TPS is in
progress and it would be completed within six months.
NTPC informed that multiple trippings due to Y-N and B-N faults are being noticed in recent past in 220 kV Kanti TPS -Gopalganj line-II which caused frequent jerks in the MTPS units. PCC advised BSPTCL to carry out the line patrolling immediately and resolve the clearance issues, if any. NTPC added that healthiness of PLCC system of all the 220kV lines at 220kV Kanti TPS needs to be checked. PCC advised BSPTCL and Powergrid to check the healthiness of PLCC system in coordination with Kanti TPS.
ITEM NO. C.2: Total Power failure at TLDP-III S/s on 27.10.18 at 10:24 hrs.
There was a Y-B fault in TLDP III – NJP – S/C near to TLDP-III S/s which was cleared from both the end in zone-I of distance protection. Before tripping of the above circuit two units of TLDP-IV got tripped due to operation of GT neutral O/C protection. It was also seen from disturbance recorder that there was a high neutral current(i.e. 40 A) flowing in TLDP III – NJP – S/C for about 1 sec before the tripping of the circuit in Y-B fault. In 73rd PCC, WBSETCL and NHPC were advised to review the DEF settings for proper protection coordination between the transmission lines and generating station. In 74th PCC, PRDC was advised to coordinate the settings with reference to the GT of TLDP end. NHPC, WBSETCL & PRDC may update.
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Deliberation in the meeting PRDC explained the disturbance with a presentation. PCC opined that the DEF settings of Generator Transformers at TLDP end need to be set to higher value for proper coordination between the transmission line and the generating units. After detailed deliberation, PCC decided the following:
1. ERPC and PRDC would determine the DEF settings for proper coordination with line protection and Generator Protection.
2. First the DEF setting for the transmission line connected to TLDP end would be determined.
3. After that, DEF setting of GT shall be calculated for worst possible scenario i.e. one unit of TLDP in operation.
4. The calculated DEF setting for the GT will be the reference settings for all the other GTs. PCC decided to submit the draft settings to NHPC and WBSETCL. The settings would be finalised in next PCC Meeting. ITEM NO. C.3: Implementation of differential protection for short distance lines in different
substations connected to Powergrid ER-II. The Lines where line differential protection are to be implemented are as follows:
Sl. No.
Substation name
Name of the Line Line length in km
Line owned by
1 Siliguri
132KV SLG (PG) - NJP (WBSETCL) Ckt. 10 WBSETCL
2 132KV SLG (PG) - NBU (WBSETCL) Ckt. 10 WBSETCL
In 40th ERPC & TCC Meeting, West Bengal requested to review the implementation of differential protection for the above lines in lower forums of ERPC.
Members may discuss. Deliberation in the meeting PCC decided to discuss the issue in next PCC meeting. ITEM NO. C.4: Protection Audit and checking of relay settings in transmission
system/distribution system within States. CERC vide its order dated 26th March, 2018 in petition no. 09/SM/2015 directed RPCs to take up the issue of protection audit and relay settings in transmission system/distribution system within states. In 77th PCC meeting, DVC,OPTCL and West Bengal informed that healthiness of the protection system including the relay settings in the intrastate sub-transmission system/distribution system is being carried out once in a year during the annual maintenance. PCC advised all the other constituents to submit their practice of carrying out protection audit and checking of relay settings in transmission system/distribution system to ERPC. JUSNL, BSPTCL and Sikkim may update.
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Deliberation in the meeting PCC advised JUSNL, BSPTCL and Sikkim to submit the details at the earliest. ITEM NO. C.5: Protection Coordination for New Lines/ICTs Prior to First Time Charging-
ERLDC Several new elements are being added in the Eastern region System in every month. The addition of new elements changes the network configuration and thus impact the protection setting of existing elements in the grid. It has been observed on various occasion that when a new element is added (like Transmission line/ICT) which directly impact the Remote end Protection setting of transmission lines connected from that substation, the protection coordination is not being done. In view of the above, it is desired to adopt the following philosophy for ensuring the protection coordination w.r.t New Transmission Lines/ICT/Elements:
Prior to Charging of New Elements:
The Utility will first take a confirmation from the utilities from where its transmission element is directly connected through email.
In addition, the utility whose element is being charged will also take a confirmation from all remote ends substations through email that protection setting for the lines which are directly connected with substations where the new element is being integrated has been completed.
In order to achieve so, the Utility may provide the information regarding new elements to all remote end substations prior to 30 days of charging to provide adequate time for remote end utilities for calculation and keeping the setting ready as group setting in case it is required to be changed.
Remote end utilities will confirm the substation within 7 days of receipt of the email.
ERLDC will intimate all the associated station regarding charging of the new elements.
After Charging of New Elements:
The Owner utility will also intimate the remote end substation regarding charging of the element and confirm ERLDC.
Members may discuss.
S/S A S/S B
S/S C
S/S D
S/S E
S/S F
S/S G
New Element
Remote end Substations for New Transmission
line between A-B here are Substation C,
D,E,F,G
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Deliberation in the meeting After detailed discussion PCC decided that:
1. The utility which is going to charge any new elements shall inform the remote end utility in advance of 30 days regarding the details of element and relevant parameters along with the charging date.
2. If addition of new element is an ICT or a line whose length is more than the existing longest line or less than the existing shortest line from the substation, remote end confirmation is mandatory before charging of the line.
3. The remote end utility should review their settings and confirm the main utility within 15 days of the receiving the details.
ITEM NO. C.6: Protection coordination w.r.t. Bus Split Arrangement at Maithon, Durgapur
and Kahalgaon Substation-ERLDC To control the fault level in Eastern Region, CEA and CTU have conducted the study based on which Bus split scheme has to be implemented at Maithon, Durgapur, Bihar Sharif and Kahalgaon substation. Bus splitting is operational at presently Maithon and is ready at Durgapur and Kahalgaon. It is known that with splitting of bus, the short lines/long lines will change for the lines connected at these substations and will require change in protection setting at remote ends for the transmission elements connected with these substations. In addition to these, depending on operational scenario, there may a requirement that bus split has to be made close and accordingly there is requirement of Group setting. In view of the above there is need of deciding which lines protection setting will be changed and based on that ERLDC can issue Reliability circular to ensure the proper protection setting during various operational scenario. The list of substations along with the new bus confirmation is given and remote end utilities may kindly confirm for which lines protection setting need to be changed and requirement of group setting.
(i). Maithon
Section Name of Line
Length and Conductor
Type
Group 1 setting from the Remote
end
(Bus Split Mode)
Group 2 setting from the
remote end
(Bus Close Mode)
Maithon A
(Bus 1 & 2)
400 kV Maithon Gaya 1
277 km,
Quad Moose
400 kV Maithon Gaya 2
277 km,
Quad Moose
400 kV Maithon-Kahalgaon 2
172 km,
Twin Moose
400 kV Maithon-Jamshedpur
153 km,
Twin Moose
400 kV Maithon-Mejia 1
60 km,
Twin Moose
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400 kV Maithon-Mejia 2
60 km,
Twin Moose
400/220 kV ICT 1
400/220 kV ICT 2
Maithon B
(Bus 3 & 4)
400 kV Maithon-Kahalgaon 1
172 km,
Twin Moose
400 kV Maithon-MPL 1
31.5 km,
Twin Moose
400 kV Maithon MPL 2
31.5 km,
Twin Moose
400 kVMaithaon-Ranchi
199.8 km, Twin Moose
400 kVMaithaon-RTPS
44 km,
Twin Moose
400 kV Maithaon-Durgapur 1
70.77 km, Twin Moose
400 kV Maithaon-Durgapur 2
70.77 km, Twin Moose
400 kV Maithon-Mejia 3
83.7 km,
Twin Moose
(ii). Kahalgaon
Section Name of Line Length and Conductor
Type
Group 1 setting from the
Remote end
(Bus Split Mode)
Group 2 setting from the remote
end
(Bus Close Mode)
Kahalgaon A
(Bus 1 & 2)
400 kV Kahalgaon-Lakhisarai 1
145 km,
Twin Moose
400 kV Kahalgaon-Lakhisarai 2
145 km,
Twin Moose
400 kV Kahalgaon A- Maithon B
172 km,
Twin Moose
400 kV Kahalgaon-Farakka 3
95 km,
Twin Moose
400 kV Kahalgaon-Farakka 4
95 km,
Twin Moose
400/132 kV ICT 1
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400/132 kV ICT 1
Kahalgaon B
(Bus 3 & 4)
400 kV Kahalgaon-Banka 1
47.7 km,
Twin Moose
400 kV Kahalgaon-Banka 2
47.7 km,
Twin Moose
400 kV Kahalgaon-Barh 1
217.2 km,
Quad Moose
400 kV Kahalgaon-Barh 2
217.2 km,
Quad Moose
400 kV Kahalgaon B- Maithon A
172 km,
Twin Moose
400 kV Kahalgaon-Farakka 1
95 km,
Twin Moose
400 kV Kahalgaon-Farakka 2
95 km,
Twin Moose
(iii). Durgapur
Section Name of Line Length and Conductor
Type
Group 1 setting from the Remote
end
(Bus Split Mode)
Group 2 setting from the
remote end
(Bus Close Mode)
Durgapur A
(Bus 1 & 2)
400 kV Durgapur-Farakka 1
146 km,
Twin Moose
400 kV Durgapur-Bidhan Nagar 1
11 km,
Twin Moose
400 kV Durgapur-Bidhan Nagar 2
11 km,
Twin Moose
400 kV Durgapur-Jamshedpur
177 km,
Twin Moose
400 kV Durgapur-Sagardighi 1
127 km,
Twin moose
400 kV Durgapur-Sagardighi 1
127 km,
Twin moose
400/220 kV ICT 1
Durgapur B
(Bus 3 & 4)
400 kV Durgapur Maithon 1
70.77 km.
Twin Moose
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400 kV Durgapur Maithon 2
70.77 km.
Twin Moose
400 kV Durgapur-Farakka 2
150 km,
Twin Moose
400/220 kV ICT 2
(*Conductor Length and Type is based on information provided by utilities for PSS/E base Case preparation)
Members may discuss. Deliberation in the meeting PCC advised concerned constituent to implement the relay settings for different bus configuration and enable the group settings accordingly. ITEM NO. C.7: Protection coordination w.r.t. Angul Bypass Arrangement-ERLDC PGCIL has intimated that Angul Bypass Scheme will be completed by end of April 2019. The bypass will result in the Breaker Bypass of 400 kV Angul substation for 400 kV Angul-Talcher/400 kV Angul-Meramundali one ckt and 400 kV Angul-Bolangir/400 kV Angul-Meramundali one ckt. This will create 400 kV Meramundali-Angul and 400 kV Meramundali-Bolangir dicer circuit. However, to ensure proper protection coordination following details are desired.
1. Protection philosophy and logic for the bypassed circuits at remote ends
2. Requirement of protection coordination for GMR/JITPL circuits at Angul
3. Requirement of protection coordination for remote end of Talcher/Meramundali and
Bolangir due to these lines.
4. Charging philosophy for these lines if tripped on fault or made out during planned/forced
outage.
Members may discuss. Deliberation in the meeting PCC advised OPTCL and NTPC to review their protection settings on account of the above bypass arrangement at 400 kV Anugul S/s.
ITEM NO. C.8: Tripping of 400 kV Barh-Patna-I on 27/01/19 at 06:47 Hrs-ERLDC
It is observed from Barh end DR that during the Y phase to earth fault on 27.01.19 at 06:47 hrs, high neutral displacement took place and healthy B phase voltage has become more than 351 kV, which is more than stage 2 overvoltage setting. From the DR submitted by Barh, only “Any trip” is there and 3 phase tripping command has been issued. However, which protection has operated from Barh end is not clear during for this event. It is suspected that tripping command may have been issued by over voltage stage 2 trip. It is important to mention here that similar incident took place on 19/12/18 on the same circuit. Further, similar instances of such events has been observed in the recent past in ER system which has been brought to the notice of PCC forum where neutral displacement during fault has led to overvoltage stage 2 tripping of 400 kV lines.
It may kindly be noted that as per CEA (Technical Standards for Connectivity to the
Grid) Regulations, 2007- PART II 1.3 “earth fault factor of Generating station must be less than
1.4 , but as we found in this case earth fault factor is coming as more than 1.5 (350 kV/231 kV)”.
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In the above tripping of the line, this clause is not complied in view of which there is a need to
form a joint expert committee for root cause analysis and suggesting corrective action.
Members may discuss.
Deliberation in the meeting PCC advised Powergrid to carryout PID testing of the insulators as well as to measure the tower footing resistance of 400 kV Barh-Patna-I. ITEM NO. C.9: FOLLOW-UP OF DECISIONS OF THE PREVIOUS PROTECTION SUB-
COMMITTEE MEETING(S)
The decisions of previous PCC Meetings are given at Annexure-C9. In 73rd PCC, it was observed that latest status on the implementation of the previous PCC recommendations were not updated by the constituents regularly. All the constituents were advised to update the latest status of the recommendations as per the list given in Annexure. Members may update the latest status. Deliberation in the meeting The updated status was given in Annexure-C9. ITEM NO. C.10: Schedule of training program to be conducted by PRDC PRDC, as per the AMC, is going to conduct 2nd training programme on PDMS and PSCT in state utility premises of Eastern Region. The tentative schedule is given below:
Sl no. State Location Date Training
1. West Bengal NJP 04.02.2019-05.02.2019
on PDMS
Durgapur 07.02.2019-08.02.2019
2. Bihar North Bihar 08.04.2019-09.04.2019
South Bihar 11.04.2019-12.04.2019
3. Sikkim - 03.06.2019-04.06.2019
4. Odisha - 08.07.2019-09.07.2019
5. Jharkhand - 05.08.2019-06.08.2019
6. For All States ERPC 02.09.2019-06.09.2019 on PSCT
Members may update. Deliberation in the meeting PRDC informed that the training programmes at West Bengal and Bihar has already been conducted as per the above schedule. BSPTCL requested to conduct one more training programme for their personnel. PCC advised BSPTCL to coordinate with PRDC for arranging one more training at Bihar. ITEM NO. C.11: Zone 3 settings of ISTS lines Based on the data available in PDMS, the zone 3 settings of all ISTS lines in Eastern Region were verified and compared with the corresponding resistive reach of the line thermal loading. Zone 3 settings were also checked with the agreed protection philosophy of ER. The discrepancies observed in the settings will be presented in the meeting.
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In 67th PCC, PRDC presented the list of ISTS lines where they observed the discrepancy in zone-3 setting. In 73rd PCC, It was informed that Powergrid ER-I had verified the settings. Powergrid ER-II and Powergrid odisha will verify the settings at the earliest. In 74th PCC, Powergrid & DVC informed that they will submit the details at the earliest. DVC has submitted the zone settings data vide mail dated 16.01.19. In 77th PCC, it was informed that the zone 3 relay reach settings were compared with the thermal rating of the conductor and verified with the agreed protection philosophy. The updated settings received from the constituents are enclosed at Annexure-C11. Members may update. Deliberation in the meeting West Bengal informed that they have sent the updated settings by mail. ITEM NO. C.12: Status of 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 49 72.06
Odisha 59 42 71.19
JUSNL 34 25 73.53
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). In 77th PCC, BSPTCL has submitted the updated status. BSPTCL may explain. Deliberation in the meeting PCC advised BSPTCL to submit the details of the compliance report. ITEM NO. C.13: Schedule for 2nd Third Party Protection Audit The third party protection Audit for the following substations in Odisha are planned to be carried out in the month of May, 2019.
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1. 400 kV Talcher HVDC- Powergrid 2. 400 kV Rengali S/s- Powergrid 3. 400 kV Meramundali S/s- OPTCL 4. 400 kV JSPL S/s-CPP 5. 220 kV TTPS- NTPC 6. 220 kV Rengali S/s- OPTCL 7. 220 kV NALCO-CPP 8. 220 kV BSSL-CPP
Members may note. Deliberation in the meeting It was decided that the third party protection Audit will be conducted in the last week of May, 2019. PCC advised ERLDC, OPTCL, NTPC and Powergrid to nominate one representative for the above audit programme. ITEM NO. C.14: 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
13 220KV BUDIPADAR-KORBA-II
23.06.16 Y-N FAULT OPTCL CSEB PLCC available
will be activated in consultation with Korba
17 220 KV TSTPP-RENGALI 17.07.16 EARTH FAULT
NTPC OPTCL
by March 2018
18 220KV BUDIPADAR-RAIGARH
21.07.16 EARTH FAULT
OPTCL PGCIL PLCC defective
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
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PCC Minutes
procurement.
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 protection coupler by Jan 17
27 220 KV BIHARSARIF-TENUGHAT
07.09.16 B-N FAULT BSPTCL
TVNL
33 220KV Jamshedpur-Jindal-SC
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. OPTCL:
1. 220kV Rengali(PG)-Rengali S/Y (Proposal for Commn. in OPGW is pending): PSDF appraisal committee accepted the proposal
2. 220kV Indravati(PG)-Indravati(PH) (Proposal for Commn. in OPGW pending): PSDF appraisal committee accepted the proposal
3. 132kV Baripada(PG)-Baripada ( Tendering in Progress for OPGW): Contract awarded 4. 132kV Baripada(PG)-Rairangpur (Tendering in Progress for OPGW): Contract awarded
BSPTCL:
Sl No. Lines Status
1 220 kV Purnea(PG)-Madhepura Protection through PLCC is working properly
2 220 kV Biharsharif-BTPS new Commissioning of PLCC is under progress.
3 220 kV BTPS new- Begusarai Commissioning of PLCC is under progress.
4 220 kV Biharshariff-Bodhgaya line LILO at Khizersarai
OPGW is present. Protection is done through DPC.
5 220kV MTPS-Motiari line OPGW is installed.
6 220KV Madhepura-New Purnea D/C Protection through PLCC is working properly
7 220KV Muzaffarpur-Hajipur D/C line Protection through PLCC is working properly
8 220KV Patna-Khagaul-SC PLCC Panel working properly.
In 77th PCC meeting, respective constituents were advised to take the necessary action to implement PLCC. Members may update. Deliberation in the meeting Members noted.
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ITEM NO. C.15: Disturbance monitoring equipment(DME) standardization The power system is routinely subjected to faults or disturbances which can range from transient
faults on transmission lines to system-wide disturbances involving multiple control areas, states
and even countries. Investigation of each incident is critical in optimizing the performance of
protection systems with the goal of preventing future incidents from becoming wide-area
disturbances. The tools required to perform post-incident analyses include DME which can
capture pre-event, event, and post-event conditions with a high degree of accuracy.
Recorders can be classified into two categories:
• FR (Fault Recorder) • Sequence of events Recorder (SER) For FR (Fault Recorder) following points may be standardized:
a. Deployment b. Record Length c. Triggers d. Sampling Rates
For Sequence of events Recorder following points may be standardized:
a. SER Capability b. Point Assignments c. Use of RTUs for SER
Common issues:
a. Data format b. Power Supply c. Monitoring
Reference documents for this:
1. NERC Standard PRC-002-2 Disturbance Monitoring and Reporting Requirements 2. NPCC Regional Reliability Reference Directory # 11 Disturbance Monitoring Equipment
Criteria In 74th PCC, all the constituents were advised to submit their comments/observations relating to
the draft standard.
PCC also decided similar kind of standard would be prepared for Transformer Protection and
Busbar Protection.
In 75th PCC, PRDC presented the draft standard for Transformer Protection and Busbar
Protection.
In 77th PCC, all the constituents were advised to submit their comments on draft standard to ERLDC and ERPC by next PCC meeting. The draft standard is attached at Annexure-C15. Members may update.
Deliberation in the meeting
PCC advised all the constituents to submit their comments at the earliest.
***************
Disturbance occurred at 400/220/132/33 KV Lapanga GSS on 14.03.2019.
Date 14.03.2019 ,Time- 13.39 Hrs.Station : Lapanga 400/220/132/33kV GSS
1. 400KV LAPANGA-IB CIRCUIT -II (Both Main CB and Tie CB got tripped).D/P RELAY:- DIST FWD , Z1,DIST-0.9KM ,
IL1-36.116 KA , IL2-31.166 KA , IL3-44.200A. 2. 400KV LAPANGA-IB CIRCUIT -I( Both Main CB and Tie CB got
tripped)D/P RELAY:- DIST FWD, Z3 Pick Up, DIST-42.5KM
IL1-13.591 KA , IL2-12.845 KA , IL3-93.925A & I>4(STUB)
3. Bus bar protection (Zone-I) for 400KV Main Bus-I operated due to which all Breakers Connected to Bus 1 tripped.
4. There was no interruption in Load flow from Sterlite end to Meramundali end through Lapanga.
ANNEXURE-B1.1
BUS 1400 KV
BUS 2400 KV
ICT 1FUTURE BAY
FUTURE BAY
FUTURE BAY
FUTURE BAY
403402401
407 408
409
410 411 412
413 414 415
416 417418
FUTURE CT
FUTURE CT
FUTURE CT
FUTURE CT
FUTURE CTFUTURE CT
FUTURE CT
OPGC CKT 1 MM CKT 1
OPGC CKT 2
MM CKT 2 STRLT CKT 2
STRLT CKT 1
PRE-FAULT CONDITION ON 14.03.19
404 405 406
FUTURE CT
NOT CHARGED YET
ICT 2
Load Flow Condition at 13.00 HrsBay No.
Name of the Feeder
Time Stamp Load in MW Load in MVar
402 Tie 1 13.00 Hrs. 15.4 0.2403 ICT 1 13.00 Hrs. -126.9 24.8408 TIE 3 13.00 Hrs. -1.4 -1.3409 OPGC CKT 2 13.00 Hrs. 0.2 -17.5410 OPGC CKT 1 13.00 Hrs. -0.3 -17.2411 Tie 4 13.00 Hrs. -1.3 -5412 Meramundali CKT 1 13.00 Hrs. -29 49.8413 Meramundali CKT 2 13.00 Hrs. -29.1 -29.2414 TIE 5 13.00 Hrs. -12.4 -5.8415 STERLITE CKT 2 13.00 Hrs. 85.5 3.5416 STERLITE CKT 1 13.00 Hrs. 89.1 14.5
417TIE 6 13.00 Hrs.
5.3 0.3
BUS 1400 KV
BUS 2400 KV
ICT 1FUTURE BAY
FUTURE BAY
FUTURE BAY
FUTURE BAY
403402401
407 408
409
410 411412
413 414 415
416 417418
FUTURE CT
FUTURE CT
FUTURE CT
FUTURE CT
FUTURE CTFUTURE CT
FUTURE CT
OPGC CKT 1 MM CKT 1
OPGC CKT 2
MM CKT 2 STRLT CKT 2
STRLT CKT 1
FAULT CONDITION ON 14.03.19
404 405 406
FUTURE CT
NOT CHARGED YET
ICT 2
Post Fault Status of 400 KV feeders
DIA No. Bay Name. Breaker Status Connected BUS Remarks
01402 TIE CB TRIPPED
BUS 1 ICT 1 WAS IN CHARGED CONDITION THROUGH 403 MAIN CBICT 1 403 MAIN CB CHARGED
BUS 2
02408 TIE CB TRIPPED
BUS 1 IB CKT 2 TRIPPED.IB CKT 2 409 MAIN CB TRIPPED
BUS 2
03
IB CKT 1 410 MAIN CB TRIPPED BUS 1
IB CKT 1 TRIPPED.MERAMUNDALI CKT 1 WAS IN CHARGED CONDITION
THROUGH 412 MAIN CB.411 TIE CB TRIPPED ------
MERAMUNDALI CKT 1 412 MAIN CB CHARGED
BUS 2
04
MERAMUNDALI CKT 2 413 MAIN CB TRIPPED
BUS1MERAMUNDALI CKT 2 WAS IN
CHARGED CONDITION THROUGH 414 TIE CB.STRELITE CKT 2 CHARGED
THROUGH 415 MAIN CB.414 TIE CB CHARGED
---------
STERLITE 2 415 MAIN CB CHARGED
BUS 2
05
STERLITE 1 416 MAIN CB TRIPPED BUS 1
STERLITE CKT 1 WAS CHARGED THROUGH 417 TIE CB.
417 TIE CB CHARGEDBUS 2
Analysis of Fault1. Line Fault Occurred at OPGC CKT 2 For which connected
Main Breaker and Tie Breaker Tripped and cleared the fault in Zone-1 operation.(408 & 409 CB)
2. 408 Tie CB initiated the BUS BAR tripping which Tripped the Bus-1. While checking LBB relay it is found that configuration for Breaker fail condition was taken a status of Breaker open along with current profile.
3. OPGC CKT-1 tripped with STUB protection. While its PSL file checked the Isolator Status was found missing.
4. Due to Bus Bar Operation all Bus -1 connected CBs were Tripped. But there was no interruption of power flow between Sterlite to Meramundali.
Remedial Actions Taken
1. The configuration in LBB relay for breaker Status was removed from 408 Tie LBB. The same is checked for all the Tie LBB relays.
2. Regarding STUB protection Operation , it is rectified by adding its isolator STATUS to PSL file . The same has been checked in other relays and found OK.
Incident No. 310319/1 Dtd: 07-04-19 Report on the incident in Eastern Region involving ISTS system
1) Date / Time of disturbance: 31-03-19, 15:21 hrs.
2) Category : - GI -II
3) Systems/ Subsystems affected: Berhampur
4) Quantum of load/generation loss: No load or generation loss was reported in Indian part due to thisincident. But there was around 850 MW loss of power transfer to Bangladesh due to whichBangladesh grid frequency dropped to 48.87 Hz from 50.8 Hz.
5) Major elements tripped:
400 kV Berhampur – Bheramera D/C6) Network across affected area
Figure 1: Network across affected area
Annexure-B3
7) Sequence of events & Detailed Analysis:
400 kV Berhampur – Bheramera D/C tripped at 15:21 hrs due to B-N fault followed by blocking of both
poles at Bheramera back to back HVDC converter station. Unsuccessful attempt of Auto-reclose
operation has been observed in one circuit (Circuit No is not mentioned in DR files). In another circuit,
A/R operation started in B phase in case of MCB (main circuit breaker) and in Y phase in case of TCB (tie
circuit breaker). Reason for A/R operation in different phases in MCB of TCB may be investigated (F/C
3.74 kA and 9.34 kA in Y & B phases respectively; Voltage 233 kV and 197 kV in Y & B phases
respectively). After 40 ms, all three phases tripped in case of both MCB & TCB. As per verbal information,
fault initially was in B phase. Later current in Y phase increased resulting three phase tripping. In PMU
data, fault has been observed in B phase along with unsuccessful A/R attempt. As per report received,
fault was in line I at very close to Berhampur end.
As per verbal information from ER-II, A/R operation in different phases in case of MCB & TCB is due to
wrong recording in DR output.
8) PMU observation:
Figure 2: Three phase voltage captured at the time of the event
9) Restoration:
Pole 1 deblocked at 16:14 hrs. and pole -2 at 16:32 hrs. 10) Discrepancies observed:
During uploading of DR output at PDMS or sending of DR output through mail, line name, circuit No and
location of DR may be properly mentioned. POWERGRID ER-II may confirm about the rectification of tag
name of MCB/TCB in DR output.
11) Status of Reporting:
Detail report along with DR/EL are received from ER-II.
Annexure I: DR recorded at Berhampur end (Circuit no not mentioned)
Trigger31-03-2019
15:20:28.803
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
LINE_A_IL1/mA
-0
200
400
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
LINE_A_IL2/A
0.00
0.25
0.50
0.75
1.00
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
LINE_A_IL3/A
0
1
2
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
LINE_A_IN/A
0.0
0.5
1.0
1.5
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
LINE_UL1/V
10
20
30
40
50
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
LINE_UL2/V
0
25
50
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
LINE_UL3/V
20
40
60
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
PUA_HEALTHYSTUB_RELEASE
L1 FUSE FAILBFR-TRIP2
AR_UNSUCBFR-OPTD
CTSU_FAILPSB-OPTD
PHS-STFWPEPHS-STFWL3PHS-STFWL2PHS-STFWL1
ZCAL_IREVBLZCAL-TRWEI
ZCOM-TRIPTESTEDM/T_LBBBB_OPD
STF_OPDOVST1/2DTRC1/2
DEF_OPDM1/2_CR
M/T_CBARM2_TRIPM1_TRIP
T_CB_BOT_CB_YOT_CB_ROM_CB_BOM_CB_YOM_CB_RO
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
CARR_SENDTR_B_MAIN_CBTR_Y_MAIN_CBTR_R_MAIN_CBDRB05-INPUT80DRB05-INPUT79DRB05-INPUT78DRB05-INPUT77DRB05-INPUT76
TIE-LBB OPTDBB OPTD
TCB BPH OPENTCB YPH OPENTCB RPH OPEN
M1 DT RECM1 TRIP
M1 CAR RECMCB BPH OPENMCB YPH OPENMCB RPH OPEN
TUV1-TRIPZ1/ZCOM TRIP
TEF_TRIPCARR_CH_FAILCARRIER_REC
STUB_TRIPSOTF_INI
86B_SUPVN86B_OPTD
M1-HEALTHYBCU_HEALTHYPUB_HEALTHY
t/s-0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
TEF1-TRIPTOC1-TRIP
TRIP_3P_TBCTRIP_3P_MAIN
AR_CLOSE_TBCAR_CLOSE_MAIN
TR_B_TBC_CBTR_Y_TBC_CBTR_R_TBC_CB
Annexure II: DR recorded at Berhampur end (Circuit no not mentioned)
Trigger31-03-2019
15:20:28.803
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
VA/kV
0
50
100
150
200
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
VB/kV
0
50
100
150
200
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
VC/kV
0
50
100
150
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
VN/kV
0
50
100
150
200
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
IA/A
0
250
500
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
IB/kA
0.0
0.5
1.0
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
IC/kA
0.0
2.5
5.0
7.5
10.0
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
IN/kA
0.0
2.5
5.0
7.5
t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
CARR_AID_TRIPDIR_TR_SEND
M1/2_CARR_SENDDEF_OPD
M1/2_SOTF_OPDMAIN1_ZR_OPTDMAIN1_Z3_OPTD
MAIN1_Z3_STARTMAIN1_Z2_OPTD
MAIN1_Z2_STARTMAIN1_Z1_OPTD
M/T_LBB_OPTDBUSBAR_OPTD
STUB_OPTDPS_BLK_OPTD
O/V_STG2_OPTDO/V_STG1_OPTD
3PH_GR_A/B_OPTDDT_REC_CH1/2
MAIN1/2_CARR_RECTIE_CB_A/R_LO
TIE_CB_A/R_OPTDMAIN_CB_AR_LO
MAIN_CB_A/R_OPTDMAIN2_TRIPMAIN1_TRIP
TIE_CB_B_OPENTIE_CB_Y_OPENTIE_CB_R_OPEN
MAIN_CB_B_OPENMAIN_CB_Y_OPENMAIN_CB_R_OPEN
HVDC Bheramara Bipole tripping on 31st March 2019
Antecedent Condition (at 15:19 hrs): -
All India Demand: 151390 MW
Indian grid frequency: 49.94 Hz
Bangladesh frequency: 51.00 Hz
Flow on HVDC Bheramara Bipole: 425 MW/each pole
Snapshot of Bheramara region prior to incident is given below: -
Incident Summary: -
On 31st March 2019, at 15:21 hrs 400 kV Berhampur-Bheramara D/C tripped due to B-N fault
as reported by ERLDC. In the event both poles of HVDC Bheramara got blocked due to non-
availability of incoming AC feeders. Due to loss of supply 850 MW through HVDC Bheramara
Bipole, the Bangladesh frequency dipped to 50.17 Hz from 51.00 Hz. 400 kV Berhampur-
Bheramara-I & II normalised at 16:10 & 15:51 hrs. Also HVDC Bheramara Pole-I& II deblocked
at 16:14 & 16:32 hrs respectively.
Sequence of events (as per SCADA data): -
15:21-> 400 kV Berhampur-Bheramara-I (tripped from both ends).
15:21-> 400 kV Berhampur-Bheramara-II (tripped from Berhampur end only).
15:21-> Both poles of HVDC Bheramara got blocked.
15:48->400 kV Berhampur-Bheramara-II charged from Berhampur end.
15:51->400 kV Berhampur-Bheramara-II charged from Bheramara end.
16:07->400 kV Berhampur-Bheramara-I charged from Berhampur end.
16:10->400 kV Berhampur-Bheramara-II charged from Bheramara end.
16:14-> HVDC Bheramara pole-I delocked.
16:32-> HVDC Bheramara pole-II delocked.
Analysis based on DR
DR of 400 kV Berhampur-Bheramara-I at Berhampur end
From Main-I DR, it appears that at Berhampur end fault is detected in B-phase under
Zone-I at 15:20:28.800 and it has tripped after taking unsuccessful auto reclosure at
15:20:29.960. The fault current detected in B-Phase was 12.864 kA. The snapshot of
DR of aforesaid Circuit-I at the time of unsuccessful auto reclosure is given below.
Fig 2: - DR of 400 kV Berhampur-Bheramara-I at Berhampur end
B-Phase
already
opened
B-Phase A/R attempt
All phases tripped. Due
to persistent fault in
B-Phase.
DR of 400 kV Berhampur-Bheramara-II at Berhampur end
From Main-I DR, it appears that Zone 3 had taken start at 15:20:28.817. At
18:20:28.884, 3-phase trip command was initiated but which relay had initiated it is
not clear from DR (fig 3). It is the same time instant in which B-phase of ckt-I was
opened. As shown in fig 3, after 15:20:28.817 R & Y phase voltage is still there and B-
phase voltage is less in compared to other phases as B-phase of ckt-I was already in
opened condition. This is only possible when ckt-II won’t trip from Bheramara end.
Also in post incident, CB status of Berhampur ckt-II at Bheramara end is found to be in
closed condition in SLD of Bheramara substation. The SLD of Bheramara substation is
given below in fig 5.
Fig 3: - DR of 400 kV Berhampur-Bheramara-II at Berhampur end
The snapshot of DR in which voltage value of phases (ckt-II) becomes zero is given below in
fig 4. The time instant (15:20:29.960) at which all voltage values are zero is the same time
at which ckt-I had tripped (refer to fig 2). Thus after this there would be no infeed power to
HVDC Bheramara Bipole and it got blocked.
All phase tripped at
15:20:28.800.
3-phase trip command
given but which relay
initiated it is not clear.
R & Y phase voltage is still
available as ckt-II didn’t
trip from Bheramara end.
Fig 4: - DR of 400 kV Berhampur-Bheramara-II at Berhampur end
Fig 5: - SLD of Bheramara (at 15:22 hrs)
Voltage is zero
in all phases
CB in closed
condition
Analysis based on PMU
At NLDC, the nearest available PMU is of Subashgaram sub-station. In PMU, unsuccessful auto
reclosure has been captured due to persistent fault in B-Phase and fault clearing time is 80
ms. The 3-phase voltage and current PMU of Subashgaram is given below: -
Fig 6: -3-Phase Voltage PMU of Subashgaram
Fig 7: -3-Phase Current PMU of Subashgaram-Jeerat
The tripping of Bipole resulted in excess power of 850 MW in INDIAN grid and absorption of
excess power by generators in INDIAN system led to frequency rise to 50.095 Hz from 50.021
Hz. After this due to primary response by generators, frequency settled down to a lower value
of 50.07 Hz. The INDIAN grid frequency is given below in fig 8. In this event All India FRC comes
out to be 17346 MW/Hz (850/.047).
Fig 8: - INDIAN Grid Frequency
Analysis based on SCADA data
Before the incident, each block of Bheramara Bipole was carrying 425 MW towards
Bangladesh side. Individual block wise power flow is suspected in the incident at NLDC SCADA.
HVDC Bheramara is connected to India through two 400 kV lines i.e. 400 kV Bheramara-
Berhampur. The flow on 400 kV lines is given below: -
Fig 9: - Flow on 400 kV Bheramara- Berhampur D/C
In the event ckt-I had tripped from both ends, but ckt-II tripped from Berhampur end only.
In post incident, both 400 kV bus at Bheramara would became dead due to non-availability of
any incoming feeder. Line MVAR of both ends on aforesaid lines is given below: -
Fig 10: - Line MVAR of 400 kV Bheramara- Berhampur D/C
Sensitivity of tripping of Bipole in nearby 400 kV lines is given below: -
Fig 11: - Sensitivity on 400 kV lines
ElementsAt 15:20 Hrs
(before the event)
At 15:22 Hrs
(after the event)Delta P Sensitivity
HVDC Bheramara bipole 850 0 out out
400 kV Farakka-Sagardighi D/C 376 190 -186 -22%
400 Kv Sagardighi-Berhampur D/C 404 -120 -524 -62%
400 Kv Sagardighi-Subashgram 286 335 49 6%
400 Kv Sagardighi-Durgapur D/C 183 382 199 23%
400 kV Sagardighi-Jeerat 375 436 61 7%
400 kV Farakka-Berhampur D/C 456 125 -331 -39%
400 kV Farakka-Malda D/C 206 364 158 19%
400 kV Farakka-Khelgaon Q/C 84 390 306 36%
400 kV Farakka-Durgapur D/C 295 396 101 12%
400 kV Farakka-Gokarna D/C 392 366 -26 -3%
With the loss of 850 MW power to Bangladesh, their(Bangladesh) grid frequency dipped to
50.17 Hz from 51.00 Hz. By 15:25 hrs, their grid frequency jumped to 50.61 Hz in steps.
Bangladesh have their SPS scheme at their end with the tripping of Bipole, but we yet to
receive SPS document from NLDC Bangladesh. Indian and Bangladesh Grid Frequency is given
below: -
Fig 12: - Indian and Bangladesh Grid Frequency
To evacuate the power from HVDC Bheramara, there are total six nos of 220 kV lines from it.
Four 220 kV lines connected to Ishurdi s/s and rest two lines connected to Khulna south.
Before the event, flow on 220 kV Bheramara-Khulna south d/c was 115 MW each ckt and in
post incident power flow dipped to 56 MW each ckt. Flow on 220 kV Bheramara-Khulna south
d/c is given below. From plot it appears that some load shedding has been done in Khulna
south region after the incident.
Fig 13: - Flow on 220 kV Bheramara-Khulna south d/c
In pre incident flow on each ckt of 220 kV Bheramara-Ishurdi-Q/C was 107 MW and in post
incident, flow in Q/C was 40 MW in direction from Ishurdi to Bheramara end. Flow on 220 kV
Bheramara-Ishurdi-Q/C is given below: -
Fig 14: - Flow on 220 kV Bheramara-Ishurdi-Q/C
As per Bangladesh NLDC PSP report for dated 31st March 2019, Bangladesh demand was 7500
MW and out of it power being taken from India through HVDC Bheramara was approximately
11 %. The energy curve from Bangladesh PSP report is given below: -
Fig 15: - Energy curve of Bangladesh
Annexure 1 - Snapshot after the Incident (at 15:22 hrs)
Annexure-B6
LINE NAME TRIP DATE TRIP TIME
RESTORATION DATE
RESTORATION TIME
Relay Indication LOCAL END
Relay Indication REMOTE END
Reason Fault Clearance time in msec
Remarks As discussed in PCC meeting
400KV MEERAMUNDALI-GMR-SC 01-03-2019 16:43 01-03-2019 17:16 DT Received from GMR End
END DT Received from GMR E -- No Fault observed in PMU Rectified
220KV BARIPADA-BALASORE-II 02-03-2019 5:23 02-03-2019 15:57 O/C, B Ph E/F O/C B-Ph E/F -- No Fault observed in PMUDT received in Baripada end; OPTCL to share Balasore end DR.
400KV RAJARHAT-JEERAT-SC 04-03-2019 19:23 04-03-2019 19:52 DT Received DT Received at Jeerat -- No Fault observed in PMU Gas pressure problem at Rajarhat end
400KV KHARAGPUR-CHAIBASA-II 07-03-2019 10:32 07-03-2019 11:13 DT Received DT Received DT received -- No Fault observed in PMU Human error at Chaibasa end
220KV MAITHON-DUMKA-II 23-03-2019 12:36 23-03-2019 13:33 DT Receipt DT Receipt at Maithon -- No Fault observed in PMU JUSNL to share Dumka end DR.
220KV BUDHIPADAR-RAIGARH-SC30-03-2019
12:1430-03-2019 13:15
Z1,15.2 KM,4.39KA B-N,2 KA ,21 KM B-N Fault1000 msec PGCIL Orissa to collect details from PGCIL WR-1 and
intimate the details to ERLDC/ERPC
400KV BIHARSARIFF(PG)-MUZAFFARPUR(PG)-I 01-03-2019 10:20 01-03-2019 10:25 Y-N , A/R Successful Y-N Fault 500 msec No A/R operation ERTS-1 to share the details of tripping and DR
400KV NEW PURNEA-BIHARSARIFF(PG)-I 02-03-2019 0:08 02-03-2019 12:08 YN, 8.38 KA, 35.6 KM Y-N Fault < 100 msec No A/R operationLine is presently idle charge dur to tower collpase so A/R is off
220KV FSTPP-LALMATIA-SC 09-03-2019 10:49 09-03-2019 18:40 B-N, 2.2 kA, 63 km from FSTPP B-N Fault < 100 msec No A/R operation NTPC to update on the above issue .
400KV RANCHI-RAGHUNATHPUR-III11-03-2019 0:41 11-03-2019 1:15 Y-N ,Z-1,f/d-17km , f/c-10ka,
A/R successful Y-N Fault < 100 msec No A/R operation
400KV RANCHI-RAGHUNATHPUR-II11-03-2019 0:41 11-03-2019 1:14 Y-N ,Z-1,f/d-17km , f/c-10ka,
A/R successful Y-N Fault < 100 msec No A/R operation
220KV FSTPP-LALMATIA-SC11-03-2019
10:3811-03-2019 18:54
B-N, 64 KM DID NOT TRIP at JSEB end B-N Fault< 100 msec
No A/R operation NTPC to update on the above issue .
400KV KHARAGPUR-CHAIBASA-II 12-03-2019 12:39 12-03-2019 12:47 B_N, 162 KM, 2.47 kA, A/R successful B-N Fault
< 100 msecNo A/R operation
400KV ARAMBAGH-BAKRESWAR-SC 13-03-2019 12:14 13-03-2019 12:17 Y-N, 82KM,3.97KA Y-N Fault No A/R operation Fault has occurred during reclaim time that’s why A/R did not occurred
220KV RAJARHAT-JEERAT-I 17-03-2019 18:50 18-03-2019 17:50
R-PHASE, Z1, DIST=29Km, FC=5.2KA, charged at 20:10 did not hold;B-N,SOTF TOR TRIP, A/ L/O SORT 27.79K.M Z-2,5.729KA. at 20:09
R-N Fault < 100 msec No A/R operation
220KV MADHEPURA-NEW PURNEA-I22-03-2019 13:11 22-03-2019 13:35 BN, 2.76 KA, 20.3 KM
BN, Z1, 1.47 KA, 90.4 KM, A/R Successful
B-N Fault < 100 msec No A/R operation BSPTCL to update on the issue and action taken for ensuring A/R
400KV JEERAT-NEW CHANDITALA-SC 22-03-2019 17:00 22-03-2019 17:42 Y-N, Z2, 77 km, 4.08 kA Y-N, Z1, 300m, 11.75 kA Y-N Fault < 100 msec No A/R operation
220KV DEHRI -GAYA-II24-03-2019
12:3924-03-2019 19:17 B-N , Z-1 , F/D-42KM, F/C-
1.4KA B-N FaultNo A/R operation BSPTCL to update on the issue and action taken for
ensuring A/R
400KV RANCHI-RAGHUNATHPUR-II25-03-2019
21:0225-03-2019 21:45
YN, 10.8 KA, 17.4 KM YN, 155.5 KM, 2.79 KA Y-N Fault< 100 msec No A/R operation Event has occurred due to earth wire clearance issue of
underpassing line which has been rectifed on 12-13 April 2019.
400KV KHARAGPUR-CHAIBASA-II26-03-2019
12:5926-03-2019 13:28 Z1 19.27 , fc 5.26 kA. A/R
SuccesfulBN fault, 140.1 km FC : 1.078 kA. B-N Fault
500 msec No A/R operation
220KV DEHRI-GAYA-I 27-03-2019 13:08 27-03-2019 13:23 B-n , 15.8 km,7.91 ka, A/R successful B-N Fault
< 100 msec No A/R operation BSPTCL to update on the issue and action taken for ensuring A/R
400KV SAGARDIGHI-FSTPP-II 30-03-2019 11:44 30-03-2019 12:30 Z1,R-N,52.19KM,4.82KA R-N,Z1,FD 21KM,FC 14 KA R-N Fault < 100 msec No A/R operation
220KV KISHANGANJ(PG)-KISHANGANJ(BSPTCL)-II 31-03-2019 22:18R-N Fault(As per PMU),Tripped from BSPTCL end only
R-N Fault(As per PMU),Tripped from BSPTCL end only
< 100 msec No A/R operationBSPTCL to update on the issue and action taken for ensuring A/R
Autoreclose related issues
Miscellaneous: High Fault clearing time, Tripping on DT, No Fault observed in PMU
List of Intra Regional line tripping in the month of March 2019 where violation of protection standard has been observed
Event has occurred due to earth wire clearance issue of underpassing line which has been rectifed on 12-13 April 2019.
Sl No.
Name of the incidence PCC Recommendation Latest status
77th PCC Meeting
1. Disturbance at 400 kV Koderma(DVC) S/s on 25.02.2019 at 21:32 Hrs.
PCC advised DVC to carry out detailed earthing audit and insulation coordination of the switchyard.
PCC advised NTPC to submit the details of earthing audit carried out in Dadri station to ERPC/ERLDC.
DVC informed that the work has been initiated and the
earthing audit will be completed within two
months.
2. Disturbance at 400kV Meramundali(OPTCL) S/S on 26-02-19 at 17:50 hrs.
PCC opined that only bus side CT should be considered for configuring the busbar differential relay and advised OPTCL to modify the busbar relay configuration.
3. Tripping of 400 kV New Ranchi-Patratu-II on 22.03.19 at 22:42 Hrs-ERLDC
Powergrid informed that they would look into the issue.
76th PCC Meeting
4. Disturbance at 220 kV Katapalli S/s on 07.01.2019 at 15:40 hrs.
PCC advised OPTCL to send the details of Hindalco islanding scheme to analyze the reasons behind failure of the islanding scheme during this disturbance
5. Disturbance at 400kV Gaya(PG), 220kV Gaya and Bodhgaya on 05-01-19 at 11:20 hrs
PCC advised BSPTCL to review the Khijasarai end relay settings to avoid unwanted tripping at Khijasarai end and submit the relay settings to ERPC for inclusion in PDMS.
BSPTCL informed that they will send
the relay settings at the earliest.
6. Islanding of CESC on 19.01.19 at 1845 Hrs
PCC advised CESC to review the backup overcurrent settings at Howrah(WBSETCL) in consultation with WBSETCL
7. Mutual effect 400kV Andal-Jamshedpur-II on 400 kV Adhunik-Jamshedpur D/C
PCC advised Adhunik and POWERGRID to analyze the event in detail to find the root cause in consultation with the ERPC and ERLDC. PCC also advised Adhunik to submit the details of PSS tuning to ERLDC/ERPC
ANNEXURE-C9
74th PCC Meeting
8. Multiple tripping incident at Darbhanga at 13:33 hrs on 06-11-18 and at 15:23 hrs on 06-11-18
PCC suggested to keep the highset setting more than 7 and advised DMTCL to review the settings.
72nd PCC Meeting
9. HVDC TFR triggering standardization and reporting requirements.
PCC advised POWERGRID to submit TFR triggering criteria and TFR signal list for all HVDC station of Eastern region to ERLDC
71st PCC Meeting
10. Disturbance at 220/132 kV Motipur(BSPTCL) S/s on 15.08.18 at 13:00 hrs.
PCC advised BSPTCL to check the disturbance recorders of all the lines in 220 kV Motipur S/s and communicate the findings to ERPC/ERLDC at the earliest.
BSPTCL informed that DR of 15.08.18 is not available in the relay. They added that OEM will visit the station within next month for reconfiguration of relay.
11. Disturbance at 400 kV Farakka S/s on 19.08.18 at 15:26 hrs.
PCC advised to check the reason for not sending carrier from Farakka to Kahalgaon and non-operation of Autorecloser.
NTPC informed that the carrier
healthiness will be checked at next
available shutdown.
68th PCC Meeting 12. Issues related with
Generation Backing down during Talcher-Kolar SPS operation on 16th May 2018.
PCC advised Powergrid to explore for inclusion of pole block with ground return mode signal in the SPS logic. PCC advised NTPC also to explore for inclusion of pole block with ground return mode signal in the SPS logic.
PCC advised Powergrid and NTPC to coordinate and implement pole block with ground return mode signal in SPS.
13. Issue of Protection Coordination Observed during Blackout of Tala on 23rd May 2018.
PCC advised Bhutan representatives to submit a detailed report on the above disturbance to ERPC and ERLDC at the earliest.
R Reach
PPRelay
ModelZone3 R3-PP R3-PG
MTPS MAITHON PG
113.55 62.45 65.24 REL670 113.15
MTPS JAMSHEDPUR
139.94 76.96 65.24 REL670 139.94
105.95 29.14 32.62 P442
RTPS RANCHI PG (DC)
208.67 114.77 32.60 REL670 209
RTPS MAITHON PG (SC)
100.08 55.04 65.24 REL670 100.76
DHANBAD MAITHON PG
55.32 22.13 58.90 REL670 49.46
WARIA BIDHANNAGAR WBSETCL
28.31 11.32 58.90 REL670 68
400 kV
RTPS
DHANBAD
WARIA
MTPS
JAMSHEDPUR
RTPS
2
1MTPS
3
4
1
2
220 KV
Main - 1SL NO.
Line Details Calculated UPDATED RELAY DETAILS
From Bus Name To Bus Name Z3 Ohms (Primary)Z3 Ohms
(Secondary)
PP PNRelay
ModelZone3 R3-PP R3-PG
Relay
ModelZone3 R3-PP R3-PG
GANGTOK RANGPO
40.29 10.07 25.51 34.01 SEL 311C 11.85 - 35.5
36.62 12.21 34.01 45.34 P444 12.34 50 64.01
MELLI SILLIGURI
60.96 0.00 0.00 0.00
61.31 20.44 34.01 45.34 7SA522 20.44 12.5 30.43 - - - -
GANGTOK RANGPO
39.32 9.83 25.51 34.01 SEL 311C 7 - 6.6
37.49 12.50 34.01 45.34 P444 12.34 50 64.01
BIRPARA CHUKHA 1
68.05 27.22 44.17 58.90 P442 27.17 30 35.49 REL670 66.9 75 125
72.80 29.12 44.17 58.90 P442
BIRPARA CHUKHA 2
68.05 27.22 44.17 58.90 P442 27.17 30 35.49 REL670 73.59 82.7 137.5
72.80 29.12 44.17 58.90
BINAGURI SILIGURI 1
55.40 22.16 44.17 58.90 P444 22.15 40 61 54.5
41.68 16.67 44.17 58.90 P442 16.68 35.49 30 REL670 41 75 125
BINAGURI SILIGURI 2
55.40 22.16 44.17 58.90 P444 22.15 40 61 54.5
41.68 16.67 44.17 58.90 P442 16.68 35.49 30 REL670 41 75 125
MALDA DALKHOLI 1
112.45 44.98 44.17 58.90 P442 45 30 38.19 REL670 111 75 125
112.45 0.00 0.00 0.00
MALDA DALKHOLI 2
112.45 44.98 44.17 58.90 P442 45 30 38.19 REL670 111 75 125
112.45 0.00 0.00 0.00
RANGPO NEW MILLI
18.18 14.54 88.35 117.80 P442 17.76 32.27 32.27
24.72 19.78 88.35 117.80 P444 26.99 80 122.44 REL670 12.46 100 102
RANGPO JORTHANG
17.69 14.15 88.35 117.80 P442 17.87 80 122.4
24.72 4.94 22.09 29.45 P442 17.76 32.27 32.27
NEW MILLI JORTHANG
9.69 7.76 88.35 117.80 P444 7.78 80 122.44 REL670 9.5 100 102
17.45 3.49 22.09 29.45 P442 10 80 122
Annexure-C11
12 NEW MILLI
JORTHANG
10 RANGPO
NEW MILLI
11 RANGPO
JORTHANG
8 MALDA
DALKHOLI 1
9 MALDA
DALKHOLI 2
6 BINAGURI
SILIGURI 1
7 BINAGURI
SILIGURI 2
4 BIRPARA
CHUKHA 1
5 BIRPARA
CHUKHA 2
3 GANGTOK
RANGPO
2 MELLI
SILLIGURI
Main - 1
132 kv
SL NO.Main - 2
1 GANGTOK
RANGPO
Z3 Ohms
(Primary)
Z3 Ohms
(Secondary)
R Reach (secondary)
UPDATED RELAY DETAILS
From Bus Name To Bus Name
Calculated SettingsLine Details
SILIGURI DALKHOLI 1/Kisanganj
104.69 41.88 44.17 58.90 P442 41 30 35.52 REL670 103 75 125
104.69 0.00 0.00 0.00
SILIGURI DALKHOLI 2/Kisanganj
104.69 41.88 44.17 58.90 P442 41 30 35.52 REL670 103 75 125
104.69 0.00 0.00 0.00
BINAGURI BONGAIGAON 1
178.57 49.11 24.47 32.62 REL670 176 75 125 P442 48 20.64 20.6
173.60 0.00 0.00 0.00
BINAGURI BONGAIGAON 2
178.57 49.11 24.47 32.62 REL670 176 75 125 P442 48 20.64 20.6
173.60 0.00 0.00 0.00
BAHAARAMPUR BEHRAMARA 1
80.80 22.22 24.47 32.62 P444 20.55 20.63 20.64 REL670 74.51 75 125
80.80 0.00 0.00 0.00
BAHAARAMPUR BEHRAMARA 2
80.80 22.22 24.47 32.62 P444 20.55 20.63 20.64 REL670 74.51 75 125
80.80 0.00 0.00 0.00
BAHAARAMPUR FARAKKA
91.60 50.38 48.93 65.24 P444 46.6 20.63 41.44 REL670 94.57 75 125
69.60 38.28 48.93 65.24 P444 41 25.4 33.87
BAHAARAMPUR SAGARDIGHI 1
112.80 62.04 48.93 65.24 P444 55.45 29 37 P546 59.6 - -
50.80 27.94 48.93 65.24 P444 32.75 55 84 P546 32.78 88 74
BAHAARAMPUR SAGARDIGHI 2
112.80 62.04 48.93 65.24 P444 55.45 29 37 P546 59.6 - -
50.80 27.94 48.93 65.24 P444 32.75 55 84 P546 32.78 88 74
JEERAT SUBHASGRAM
130.40 35.86 24.47 32.62 P442 35.4 29.6 20.6 REL670 128.4 75 125
106.88 29.39 24.47 32.62 P444 29.03 29.6 20.6 7SA522 28.92 10.31 13.87
MALDA FARAKKA 1
76.00 41.80 48.93 65.24 P442 40 37.15 23.68 REL670 72.24 75 125
82.80 45.54 48.93 65.24 P442 41.4 25.4 33.87
MALDA FARAKKA 2
76.00 41.80 48.93 65.24 P442 40 37.15 23.68 REL670 72.24 75 125
82.80 0.00 0.00 0.00 P442 41.4 25.4 33.87
MALDA PURNEA 1
137.30 37.76 24.47 32.62 P442 36.4 20.63 20.69 REL670 132 100 102
133.60 36.74 24.47 32.62 P442 36.74 20.63 20.69 7SA522 36.59 10.31 13.87
MALDA PURNEA 2
137.30 37.76 24.47 32.62 P442 36.4 20.63 20.69 REL670 132 75 125
25 MALDA
PURNEA 1
26 MALDA
23 MALDA
FARAKKA 1
24 MALDA
FARAKKA 2
21 BAHAARAMPUR
SAGARDIGHI
22 JEERAT
SUBHASGRAM
20 BAHAARAMPUR
SAGARDIGHI
19 BAHAARAMPUR
FARAKKA
17 BAHAARAMPUR
BEHRAMARA 1
18 BAHAARAMPUR
BEHRAMARA 2
15 BINAGURI
BONGAIGAON 1
16 BINAGURI
BONGAIGAON 2
SILIGURI
DALKHOLI 2
13 SILIGURI
DALKHOLI 1
400 KV
14
133.60 36.74 24.47 32.62 P442 36.74 20.63 20.69 7SA522 36.59 10.31 13.87
RANGPO BINAGURI 1
130.80 71.94 48.93 65.24 P444 71.5 20.63 41.29 129
119.60 65.78 48.93 65.24 P444 64.9 41.25 41.29 REL670 101.5 75 125
RANGPO BINAGURI 2
130.80 71.94 48.93 65.24 P444 71.5 20.63 41.29 129
119.60 65.78 48.93 65.24 P444 64.9 41.25 41.29 REL670 101.5 75 125
RANGPO TEESTA 1
9.86 5.42 48.93 65.24 P442 5.35 37.5 68.75
64.13 0.00 0.00 0.00 11
RANGPO TEESTA 2
9.86 5.42 48.93 65.24 P442 5.35 37.5 68.75
64.13 0.00 0.00 0.00 6.85 25.4 33.87
SAGARDIGHI SUBHASGRAM
134.40 73.92 48.93 65.24 RCS-902D 93.98 - - RCS-902D 93.98 - -
177.28 48.75 24.47 32.62 P442 49.3 20.63 20.69 7SA522 49.3 10.31 13.87
TALA BINAGURI 3
126.00 0.00 0.00 0.00
85.20 23.43 24.47 32.62 P442 30.3 20.63 20.64 REL670 55.33 75 125
27 RANGPO
BINAGURI 1
28 RANGPO
BINAGURI 2
32 TALA
BINAGURI 3
31 SAGARDIGHI
SUBHASGRAM
29 RANGPO
TEESTA 1
30 RANGPO
TEESTA 2
26
PURNEA 2
ERPC Proposed Guide Lines
Triggering criteria for DR : Any Start
Internal protection trip signals, external trigger input, analog triggering (any phase current exceeding 1.5 pu of CT secondary current or any phase voltage below 0.8pu, neutral/residual overcurrent greater than 0.25pu of CT secondary current).
DR time window : minimum 3 seconds. minimum 2 seconds.Pre-fault time window (S): 0.5 -Post fault time window (S): 2.5 0.3Minimum sampling frequency: 1000 Hz 64 Samples Per CycleAnalog signals as per priorityA. Mandatory signals:
1. Three phase voltage 1. Three phase-to-neutral voltages2. Neutral voltage 2. Three phase currents and neutral currents.3. Three phase current 3. Neutral Currents4. Neutral current 4. Frequency
B. Optional signals:1. Mutual current 1. Polarizing currents and voltages, if used.2. Check Sync 2. Real and reactive power
3. Open Delta
The Minimum parameters to be monitored in the Fault record shall be specified by therespective RPC.
Digital signals as per priorityA. Mandatory signals:
1. Any Start2. Any trip3. Z1, Z2, Z3, Z4 pick up4. Over current and Earth fault pick up5. Over voltage stage I & II pick up6. DT send & reverse7. Carrier send & Receive8. Main three phase CB open signal9. Tie three phase CB open signal (where applicable)10. Power Swing11. SOTF/TOR12. LBB13. A/R L/O14. Main-1/2 operated15. Bus Bar trip16. VT failure17. Distance Forward & Reverse18. T1, T2, T3, T419. Broken conductor20. 86A & 86B21. A/R 1P In Prog22. A/R Fail23. STUB/TEED (where applicable)
B. Optional signals:1. Any External input2. Any Binary Input
Annexure-C15
ERPC Proposed Guide Lines
Triggering criteria for DR : Any Start
Internal protection trip signals, external trigger input, analog triggering (any phase current exceeding 1.5 pu of CT secondary current or any phase voltage below 0.8pu, neutral/residual overcurrent greater than 0.25pu of CT secondary current).
DR time window : minimum 3 seconds. minimum 2 seconds.Pre-fault time window (S): 0.5 -Post fault time window (S): 2.5 0.3Minimum sampling frequency: 3200Hz 64 Samples Per CycleAnalog signals as per priorityA. Mandatory signals:
1. Three Phase Currents & Neutral Currents of HV2. Three Phase Currents & Neutral Currents of LV3. Three Phase Currents & Neutral Currents of MV4. I_REF HV5. I_REF LV6. I_REF MV7. Voltages8. Frequency9. Differential Currents10. Restraining Currents11. Low Impedence REF-DIFF - of all windings12. Low Impedence REF-Restraining - of all windings
Digital signals as per priority1. Any Start2. Any trip3. Differential Trip3. REF Trip HV, MV & LV4. Over-current Trip5. Earth Fault Trip6. Over Flux7. Over Voltage8. Under Voltage9. 2nd Harmonic10. 5th Harmonic11. Frequency Protection12. External Trip Signals
ERPC Proposed Guide Lines
Triggering criteria for DR : Any Start
Internal protection trip signals, external trigger input, analog triggering (any phase current exceeding 1.5 pu of CT secondary current or any phase voltage below 0.8pu, neutral/residual overcurrent greater than 0.25pu of CT secondary current).
DR time window : minimum 3 seconds. minimum 2 seconds.Pre-fault time window (S): 0.5 -Post fault time window (S): 2.5 0.3Minimum sampling frequency: 3200Hz 64 Samples Per CycleAnalog signals as per priorityA. Mandatory signals: 1. 3Phase Diff Current
2. 3Phase Bias Current3. Neutral Differential Current4. Neutral Bias Current
B. Optional Signals: 1. Individual Feeder Currenrts if available2. Zone wise Differential and Bias Currents
Digital signals as per priority1. Any Start2. Any trip3. R-Phase Fault4. Y-Phase Fault5. B-Phase Fault6. Earth Fault7. Check Zone Operated8. Zone 1 BB Fault9. Zone 2 BB Fault10. Trip Bus bar Zone 1 11. Trip Bus bar Zone 212. Trip Breaker Failure Zone 113. Trip Breaker Failure Zone 214. Bus bar Differential Blocked