Agenda

for

79th PCC Meeting

Date: 21.05.2019

Eastern Regional Power Committee

14, Golf Club Road, Tollygunge

Kolkata: 700 033

EASTERN REGIONAL POWER COMMITTEE

AGENDA FOR 79TH PROTECTION SUB-COMMITTEE MEETING TO BE HELD AT ERPC, KOLKATA ON 21.05.2019 (TUESDAY) AT 11:00 HOURS

PART – A

ITEM NO. A.1: Confirmation of minutes of 78th Protection sub-Committee Meeting held on 22nd April, 2019 at ERPC, Kolkata.

The minutes of 78th Protection Sub-Committee meeting held on 22.04.19 circulated vide letter dated 08.05.19. Members may confirm the minutes of 78th PCC meeting.

PART – B

ANALYSIS & DISCUSSION ON GRID INCIDENCES OCCURRED IN APRIL, 2019 ITEM NO. B.1: Total Power Failure at major Hydro Power Stations in Sikkim.

1. On 12.04.2019 at 23:55 Hrs

At 23:55 Hrs, 400 kV Teesta 3-Kishanganj circuit tripped due to phase to phase fault in R & Y phase. This led to shifting of entire power to 400 kV Rangpo-Kishanganj single circuit. Subsequently backup over current protection for 400 kV Rangpo-Kishanganj line at Kishanganj end operated causing its tripping. As 400 kV Rangpo-Binaguri circuits were under planned outage for HTLS Reconductoring work, due to loss of major evacuation path the hydro generators in Sikkim got isolated and subsequently tripped on account of large load generation unbalance. Complete blackout occurred in the following substations:

I. 400/220/132 kV Rangpo S/s II. 400 kV Teesta V S/s

III. 400 kV Teesta-III S/s IV. 400/132 kV Dikchu S/s V. 220 kV Jorethang S/s VI. 220 kV Tashiding S/s

VII. 132 kV Chujachen S/s VIII. 132 kV Gangtok S/s Detailed report of the disturbance is enclosed at Annexure B1. Generation Loss: 1908 MW Load Loss: 17 MW Members may discuss.

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PCC Agenda

2. On 16.04.2019 at 23:30 Hrs

At 23:32 Hrs, Resistive fault occurred in the Y phase on 400 kV Rangpo-Kishanganj circuit which led to tripping of the circuit on Directional E/F porotection from Kishanganj end. During this fault, 400/132 kV ICT at Dikchu got tripped on Backup O/C protection and Unit#2 of Jorethang also got tripped on neutral O/C protection. Subsequently due to overloading of 400 kV Teesta-III- Kishanganj line the SPS operated at Teesta-III and tripped its Unit#1. Further Unit 2,3,4 & 6 of Teesta-III tripped on minimal impedance stage 2 protection. Generation Loss: 1118 MW (Teesta-III-982MW, Dikchu-100 MW, Jorethang-36 MW) Load Loss: Nil Members may discuss. ITEM NO. B.2: Total Power Failure at 220 kV Tenughat S/s on 17.04.19 at 10:16 Hrs.

220 kV Ranchi – Hatia D/C was out of service. At 10:16 hrs, 220 kV Biharshariff-Tenughat S/C tripped on R-N fault resulting into islanding of Hatia load with two running units of Tenughat and one unit of CPP Inland power. Island could not survive due to generation load unbalance leading to the load loss of around 150 MW in Jharkhand system and loss of two running units of Tenughat and 1 running unit of CPP Inland. 315 MVA ICT-I & II of Biharshariff also tripped sensing the fault of 220 kV Biharshariff-Tenughat S/C. As per PMU data, fault was cleared within 200 ms. Generation Loss: 390 MW Load Loss: 150 MW TVNL, JUSNL BSPTCL may explain. ITEM NO. B.3: Disturbance at 220 kV Patratu S/s on 29.04.19 at 12:37 Hrs At 12:37 hrs all lines emanating from Patratu tripped resulting total power failure at 220 kV Patratu S/s. As per PMU data, fault was cleared within 400 ms. Load Loss: 65 MW JUSNL may explain. ITEM NO. B.4: Total Power Failure at 220 kV Santaldih TPS S/s on 05.04.19 at 15:03 Hrs. Prior to the event, 220 kV Santaldih Bus-II was under planned shutdown and all the elements were in Bus-I. During the shifting of ST-3 from Bus-I to Bus-II, the 220 kV Bus-II side Y phase isolator did not close properly. When the isolator was tried to open, heavy arching occurred and all the elements got tripped at Santaldih. Generation Loss: 480 MW

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Load Loss: 40 MW WBPDCL may explain. ITEM NO. B.5: Total Power Failure at 220 kV Khagul S/s on 27.04.19 at 12:47 Hrs 220 kV Arrah-Khagul D/C were out of service for reducing the loading of 220 kV Patna-Sipara T/C. in addition, 220 kV Khagul-Sipara S/C was also under breakdown prior to the incident. At 12:47 hrs, 220 kV Patna-Khagul S/C tripped on B-N fault resulting total power failure at 220/132 kV Khagul S/s. As per PMU data, delayed fault clearance has been observed for this circuit for more than 300 ms. Load Loss: 147 MW BSPTCL and Powergrid may explain. ITEM NO. B.6: Disturbance at 765 kV Angul S/s on 30.04.19 at 02:15 Hrs. At 2:15hrs, 765 KV Bus-I at Angul tripped on Bus bar protection due to bursting of B-phase CT associated with Tie bay of 765 KV Angul Jharsuguda-IV. At the same time, 1500 MVA 765/400 KV ICT IV also tripped on back up O/C protection. As per PMU data, fault was cleared around 350 ms.

Load Loss: Nil Powergrid may explain. ITEM NO. B.7: Disturbance at Talcher HVDC Station on 11.04.19 at 13:39 Hrs. On 11-04-19 at 13:01 hrs +/-500 KV Talcher Kolar HVDC Pole 1 got blocked due to Emergency switch off signal receipt from Kolar end resulting reduction of power flow from 2000 MW to 1000 MW. Pole 2 was operated in metallic return mode after the incident. Due to event generation back down occurred at GMR and at JITPL. Generation Loss: 190 MW Powergrid may explain. ITEM NO. B.8: Tripping Incidences in the month of April, 2019. Other tripping incidences occurred in the month of April 2019 which needs explanation from constituents of either of the end is given in Annexure-B8. 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.

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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.

In 78th PCC 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. PCC advised BSPTCL to carry out the line patrolling in 220 kV Kanti TPS -Gopalganj line-II immediately and resolve the clearance issues, if any. PCC also advised BSPTCL and Powergrid to check the healthiness of PLCC system in coordination with Kanti TPS. Members may discuss.

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. In 78th PCC Meeting it was decided that,

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 also decided to submit the draft settings to NHPC and WBSETCL. The settings would be finalised in next PCC Meeting. Draft settings have been sent to NHPC and WBSETCL. NHPC and WBSETCL may update.

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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. 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. In 78th PCC, JUSNL, BSPTCL and Sikkim were advised to submit the details at the earliest. JUSNL, BSPTCL and Sikkim may update.

ITEM NO. C.5: 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)”. 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.

In 78th PCC Meeting, Powergrid was advised to carryout PID testing of the insulators as well as to measure the tower footing resistance of 400 kV Barh-Patna-I. Powergrid may update.

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PCC Agenda

ITEM NO. C.6: FOLLOW-UP OF DECISIONS OF THE PREVIOUS PROTECTION SUB-COMMITTEE MEETING(S)

The decisions of previous PCC Meetings are given at Annexure-C6. 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. ITEM NO. C.7: 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

In 78th PCC, 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. Members may update. ITEM NO. C.8: 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. 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-C8. In 78th PCC, West Bengal informed that they have sent the updated settings by mail. Members may update.

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ITEM NO. C.9: 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. In 78th PCC, BSPTCL was advised to submit the details of the compliance report. BSPTCL may explain. ITEM NO. C.10: 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.

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

In last PCC, 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. Members may update. 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

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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 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

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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. ITEM NO. C.12: 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

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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 78th 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-C12. Members may update.

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

Report on GD-1 Event of Blackout at Sikkim Hydro Complex on

12th April 2019 at 23:55 Hrs Event Category: GD-1

Date and Time: 12th April 2019 23:55 Hrs

Summary of the Event:

400 kV Rangpo-Binaguri circuits were under planned outage for HTLS Reconductoring work. At 23:55

Hrs, R-Y phase to phase fault occurred on 400 kV Teesta 3-Kishanganj circuit resulting in its tripping.

This led to evacuation of entire Sikkim hydro complex power through 400 kV Rangpo-Kishanganj

single circuit. However, backup over current protection which was kept enabled for this circuit at

Kishanganj end operated causing its tripping. This led to Isolation of Sikkim Hydro complex (1908

MW) with Gangtok Load (17 MW) and the island collapsed due to large load generation imbalance

causing total blackout of 400/220/132 kV Rangpo, 400 kV Teesta V, 400 kV Teesta 3, 400/132 kV

Dikchu, 220 kV Jorethang, 220 kV Tashiding, 132 kV Chujachen and 132 kV Gangtok substations. The

large generation loss led to frequency drop by 0.15 Hz in the Indian grid (50.029 Hz to 49.859 Hz).

Pre -Incident Condition at 23:54 Hrs on 12th April 2019:

Generating Station Generation (MW)

Teesta V 528

Teesta 3 1214

Jorethang 38

Tashiding 32

Chujachen 0

Dikchu 96

Transmission Line Line Flow (MW)

400 kV Teesta 3-Kishanganj 940

400 kV Rangpo-Kishanganj 943

400 kV Rangpo-Binaguri D/C Out

400 kV Teesta 3-Dikchu 270

400 kV Dikchu-Rangpo 368

400 kV Teesta V-Rangpo D/C 528

Figure 1: SCADA Snapshot of Sikkim Hydro Complex at 23:54 Hrs on 12th

April 2019

Annexure-B1

Event Overview:

Prior to the event, 400 kV Rangpo-Binaguri circuit was under planned outage for HTLS

Reconductoring work. The Sikkim Hydro complex was generating 1908 MW with 17 MW load of

Gangtok connected at 132 kV level. The surplus power of the complex was evacuated via 400 kV

Teesta3-Kishanganj and 400 kV Rangpo-Kishanganj Quad Moose ckts. The whole complex got

blackout due to the event whose chronology is given below along with SCADA snapshot in figure 2:

Time Events

23:55:11.420 R-Y Phase to Phase fault occurred on 400 kV Teesta3-Kishanganj due to conductor

snapping at 95 km from Kishanganj end.

Kishanganj End Relay: IR: 5.1 kA, IY: 6.37 kA, Zone 1, Zone 1 trip, Fault Loc : 64 km

Teesta 3 End Relay: IR: 4.33 kA, IY:3.16 kA, Zone 1, Zone 1 trip, Fault Loc: 120 km

23:55:11:489 400 kV Teesta3-Kishanganj tripped from Teesta 3 End as well as Kishanganj end in

Zone 1.

23:55:11:748 DMT O/C Stage 1 picked up in Siemens Relay 7SA522 at Kishanganj end for 400 kV

Rangpo-Kishanganj ckt. Power swing also detected in REL 670 relay at Kishanganj

in this circuit. IR=3.0 kA, IY=3.01 kA, IB=3 kA.

23:55:12:226 400/132 kV ICT at Dikchu Tripped on backup Over current protection operation

thus isolating Dikchu unit 1 and 2 from grid.

23:55:12.248 DMT O/C Stage 1 operated at Kishanganj end for 400 kV Rangpo-Kishanganj ckt.

IR=3.97 kA, IY=3.92 kA, IB=3.89 kA

23:55:12.290 Y phase opened at Kishanganj end for 400 kV Rangpo-Kishanganj ckt.

23:55:12.300 R and B phase opened at Kishanganj end for 400 kV Rangpo-Kishanganj ckt.

Islanding of Sikkim Hydro complex along with Gangtok load from the grid.

23:55:12:304 R and B phase current become zero at Rangpo end for 400 kV Rangpo-Kishanganj

ckt. Y phase current become 5.13 kA at Rangpo and Zone 1 pickup for 400 kV

Rangpo-Kishanganj ckt at Rangpo end. Y phase pole tripped at Rangpo end along

with initiation of A/R cycle. This can be due to initiation of another fault in the

ckt.

23:55:13.498 400 kV Rangpo-Kishanganj circuit Y phase pole A/R successful. Circuit already

tripped from Kishanganj End.

23:55:13.526 Teesta 3 Unit 6 tripped on Over Frequency Protection.

23:55:13.879 Teesta 3 Unit 1, 2 and 4 tripped on Over Frequency Protection.

23:55:13.880 Teesta 3 Unit 3 tripped on Over Frequency Protection.

23:55:13.882 Teesta 3 Unit 5 tripped on Over Frequency Protection.

23:55:16:511 Teesta 5 Unit 3 tripped on Over Frequency Protection

23:55:16:512 Teesta 5 Unit 1 tripped on Over Frequency Protection

23:55:16:513 Teesta 5 Unit 2 tripped on Over Frequency Protection

23:55:16:718 Jorethang Unit 2 Tripped on Low Forward Power

23:55:16:769 Tashiding Unit 1 Tripped on Unit overvoltage Protection

23:55:16.840 Sikkim Hydro complex island collapsed and Rangpo bus voltage become zero.

*Event Chronology is from DR except the Island collapse time which is from PMU.

Figure 2: SCADA Snapshot of Sikkim Hydro Complex at 23:56 Hrs on 12

th April 2019

Relay Indication:

Transmission line/ Unit

Time End 1 Relay Indication End 2 Relay Indication

400 kV Teesta3-Kishanganj

23:55:11:489 IR: 4.33 kA, IY:3.16 kA, Zone 1, Zone 1 trip, Fault Loc: 120 km

IR: 5.1 kA, IY: 6.37 kA, Zone

1, Zone 1 trip, Fault Loc : 64

km

400 kV Rangpo-Kishanganj

23:55:12.300 Zone 1, IY: 5.13 kA, Y phase to E/F, Zone 1, A/R successful after 1 second.

DMT O/C Stage 1 and 2 pickup, PSB Detected, PSB Block, After 500 ms DMT O/C stage 1 optd.

400/132 kV ICT Dikchu

23:55:12:226 Backup Overcurrent protection

Dikchu Unit 1 23:55:12:226 Isolated as 400/132 kV ICT tripped on Overcurrent stage 1 operation

Dikchu Unit 2 23:55:12:226 Isolated as 400/132 kV ICT tripped on Overcurrent stage 1 operation

Teesta 3 Unit 1 23:55:13.879 Generator Over Frequency Relay stage 2 optd followed by Turbine shutdown relay

Teesta 3 Unit 2 23:55:13.879 Generator Over Frequency Relay stage 2 optd followed by Turbine shutdown relay

Teesta 3 Unit 3 23:55:13.880 Generator Over Frequency Relay stage 2 optd followed by Turbine shutdown relay

Teesta 3 Unit 4 23:55:13.879 Generator Over Frequency Relay stage 2 optd followed by Turbine shutdown relay

Teesta 3 Unit 5 23:55:13.882 Generator Over Frequency Relay stage 2 optd followed by Turbine shutdown relay

Teesta 3 Unit 6 23:55:13.526 Generator Over Frequency Relay stage 2 optd followed by Turbine shutdown relay

Teesta 5 Unit 1 23:55:16:512 Generator Over Frequency Relay optd followed by Turbine over speed protection

Teesta 5 Unit 2 23:55:16:513 Generator Over Frequency Relay optd followed by Turbine over speed protection

Teesta 5 Unit 3 23:55:16:511 Generator Over Frequency Relay optd followed by Turbine over speed protection

Jorethang Unit 2 23:55:16:718 Low Forward Power Trip. Over frequency stage 1/2 pickup.

Tashiding Unit 23:55:16:769 Unit overvoltage Protection

Islanded System

Load/Generation Loss and Frequency Drop:

The blackout of Sikkim Hydro complex along with Gangtok load led to loss of 1908 MW of generation

and 17 MW of Load. This has led to frequency drop by 0.15 Hz in the Indian grid (50.029 Hz to 49.859

Hz) as shown in figure 3.

Figure 3: Frequency Drop during the event.

Area/substation affected:

The event has led to blackout of 400/220/132 kV Rangpo, 400 kV Teesta V, 400 kV Teesta 3, 400/132

kV Dikchu, 220 kV Jorethang, 220 kV Tashiding, 132 kV Chujachen and 132 kV Gangtok substations.

Restoration:

At 00.51 hrs on 13-04-19 132 kV Bus sectionalizer at was Rangpo closed and power was extended to

Gangtok and Chujachen by availing power from Rangit/Melli section. At 00:58 hrs, 400 KV Rangpo-

Kishenganj S/C was normalized and starting power extended to Teesta-III, Teesta 5, Dikchu, Tashding

and Jorethang.

One attempt to charge the 400 kV Teesta3-Kishanganj circuit was taken at 01:15 Hrs from Teesta 3

however the fault persisted in R phase (2.86 kA) and led to zone 2 tripping. After confirmation from

TVPTL through mail (02:47 Hrs and 07:09 Hrs) that they have patrolled the 400 kV Teesta3-

Kishanganj circuit and found healthy, charging attempt were again taken at 03:40 Hrs and 08:01 Hrs.

On both occasions, R phase to earth fault reappeared and cleared in zone 2 time where fault current

was 2.97kA. After this circuit was declared breakdown and TVTPL was instructed to utilise off line

fault locator for finding the exact location of fault and rectify. Later, it was informed by TVPTL that

one conductor of 400 kV Teesta-III-Kishanganj has fallen at a location around 95 km from Kishanganj

end. In the meantime, PGCIL ERTS-2 has returned the 400 kV Rangpo-Binaguri circuit 2 at 16:07 Hrs

on 13th April 2019.

In order to rectify the issue on the faulty line, 400 kV Rangpo-Kishanganj circuit was also taken under

shutdown by TVPTL on 13th April 2019 at 16:07 Hrs however shutdown was returned at 18:51 Hrs

due to rain at the site. On 14 April 2019 at 16:56 Hrs, 400 kV Teesta3-Kishenganj circuit was

normalised after rectification of the snapped conductor.

Analysis of PMU data:

The Rangpo and Kishanganj Substation PMU data were available with ERLDC and the same has been

analysed and the associated plots are given below.

1. Bus Voltage: Figure 4 which indicate the Positive Sequence bus voltages of 400 kV Rangpo and

Kishanganj substation during the event shows that due to the fault followed by line tripping has

led to power swing on the 400 kV Rangpo-Kishanganj circuit causing voltage to drop below 0.8

p.u. (at Rangpo). After the islanding of Sikkim hydro complex, the voltage of Rangpo bus first

became high (1.17 p.u.) due to load throw off which started reducing with field forcing of

generator excitation response and reduced to 0.3 p.u. It is observed that the voltage then

recovered back to 1 p.u. and then the Rangpo bus became dead. Thus, the islanded system

survived for around 4.54 Seconds.

Figure 4: Positive Sequence voltage of 400 kV Rangpo and Kishanganj Substation

2. Frequency: PMU has a reasonability limit for reporting of frequency (50 +/- 5 Hz). The frequency

data of Kishanganj and Rangpo bus is plotted in figure 5. It can be observed that frequency of

islanded system (Rangpo Frequency) has reached more than 55 Hz within 1.68 Seconds of the

islanding from grid indicating the huge difference between generation and load. After 55 Hz, the

value has ceased indicating that PMU is considering data as suspect.

Figure 5: Frequency of 400 kV Rangpo and Kishanganj Substation

3. Angular Separation between Rangpo and Kishanganj: Angular separation between Rangpo and

Kishanganj Bus has been plotted in figure 6. It shows that prior to the event the angular

separation was around 18 degrees which increased to 59 degrees after fault associated with

tripping of 400 kV Teesta 3-Kishanganj circuit. This high angular separation after contingency is

a cause of concern as it is more than the stability limit.

Figure 6: Angular Separation between of 400 kV Rangpo and Kishanganj Substation

4. Line Current and Line voltage for 400 kV Teesta3-Kishanganj from Kishanganj End: The line

current and line voltage as shown in in figure 7 for this line indicate R-Y phase to phase fault and

its immediate clearance within 100 ms.

Figure 7: 400 kV Teesta 3- Kishanganj circuit line current and voltage from Kishanganj End during the fault.

5. Line Current and Line voltage for 400 kV Rangpo-Kishanganj from Kishanganj End: The line

current and voltage of 400 kV Rangpo-Kishenganj circuit from Kishanganj are given inf figure 8

and 9 respectively. Line current indicate that, after tripping of 400 kV Teesta3-Kishenganj circuit,

whole power got diverted on this circuit leading to around 4.2 kA in each phase. While at the

same time voltage has also dropped indicating power swing in the system. It can be observed

from current plot that the line has tripped at 23:55:12.240 Hrs however voltage on line is

persisting indicating remote end is still not dead.

Figure 8: 400 kV Rangpo- Kishanganj circuit line current from Kishanganj End during the event.

The voltage plot shows that, as the line has tripped from Kishanganj end however there was a Y

phase A/R operation at Rangpo end. It can further be observed that as the line got tripped from

Kishanganj end, the voltage on the line became more than 270 kV which is reflective of islanded

condition of the system. The voltage then later reduced to 70 kV due to excitation system

response of generating unit in the island after the load throw off.

Figure 9: 400 kV Rangpo- Kishanganj circuit line voltage from Kishanganj

End during the event.

6. Line Current and Line voltage for 400 kV Rangpo-Kishanganj from Rangpo End: The Rangpo end

Line current and Line voltage shown in figure 10 and 11 respectively. The Line current confirms

the A/R event at Rangpo end just after the tripping of line from Kishanganj end. The line voltage

from Rangpo confirms the islanding, subsequent A/R and island survival for around 4.54

seconds. The Active power plot given in figure 12 indicates that flow on the line has increased to

2184 MW prior to tripping of circuit.

Figure 10: 400 kV Rangpo- Kishanganj circuit line current from Rangpo End during the event.

Figure 11: 400 kV Rangpo- Kishanganj circuit line voltage from Rangpo End during the event.

Figure 12: 400 kV Rangpo- Kishanganj circuit Active Power from Rangpo End during the event.

Analysis of Disturbance Recorder and event logger file:

The DR from the various ends were analysed the observation are as follows:

1. The relay has correctly operated for 400 kV Teesta3-Kishanganj in zone 1 from both ends after

the faults and cleared within 100 ms.

2. The digital status in the DR at Kishanganj end for both the lines was not properly configured.

From the event logger it is understood that the Definite meantime Overcurrent stage 1 has

operated at Kishanganj end for 400 kV Rangpo-Kishanganj end. The pickup value was 3 kA with

time delay of 500ms. The above protection should not have been enabled in the relay until VT

fuse failure issue is there.

3. When the Y phase Pole of 400 kV Rangpo-Kishanganj end tripped at Kishanganj end, the current

in Y phase pole did not ceased at Rangpo end and persisted with higher value indicating a fault in

the circuit. This High current in Y phase followed by voltage drop was seen as a Fault at Rangpo

end Relay causing single phase tripped and A/R operation.

4. The operation of backup overcurrent protection for 400/132 kV ICT at Dikchu during fault on the

400 kV Teesta3-Kishanganj circuit is not correct. This similar issue of ICT tripping on backup

overcurrent was later also observed for 400 kV Rangpo-Kishanganj tripping on directional earth

fault 16-04-19 at 23:32 Hrs.

5. During the three-trial charging of lines from Teesta 3 end, it is observed that Main 1 relay has

picked the fault in Zone 1 while Main 2 in Zone 2 however Main 2 has only given the tripping

command. SOTF has also not operated at Teesta 3 end which led to delayed tripping of circuit on

all three occasions.

Analysis of Non-Operation of SPS at Rangpo and Teesta III end:

The present interim SPS Scheme at Rangpo was implemented on 26th March 2019. The scheme

at Rangpo is as following:

Condition 1: Tripping of 400 kV Rangpo-Kishanganj S/C when its pre-tripping flow is >

650 MW (SPS Test 1) with 900 ms delay

Condition 2: Power Flow of 400 kV Rangpo-Kishanganj S/C crosses 1700 MW (SPS Test 2)

with 900ms Delay

Action: Tripping of One unit at Teesta 3, Teesta 5, Chujachen, Jorethang, Tashiding and

Dikchu

Analysis for This SPS: It is observed that the SPS condition 2 has to operate for over loading on the

400 kV Rangpo-Kishanganj after N-1 of 400 kV Teesta3-Kishanganj circuit. However, this circuit got

tripped within 0.815 seconds due to which the SPS has not operated as has a delay of 900 ms.

The Scheme implemented at Teesta 3 for Cable overloading

Two units (including the one unit identified for SPS operation from Rangpo) will

trip at Teesta III end if flow of 400 kV Teesta-III-Kishanganj exceeds 2000 Amps (1385 MW). The SPS

should have operated and given a relief by tripping of one unit immediately after cable overload

however it has also not operated. Teesta 3 intimated that they have given 1.5 second delay in this

scheme due to which this also has not operated.

Analysis of System FRC Response during the event:

Operation Issues Observed:

1. Conductor Snapping of 400 kV Teesta3-Kishanganj circuit: The Event initiated due to one

conductor snapping in the newly constructed line of TVPTL causing phase to phase fault in the

system. The Reason for conductor snapping and other details along with Patrolling report has

yet not been submitted by TVPTL to ERLDC/ERPC.

2. Intimation of Healthiness of Circuit to ERLDC by TVPTL: TVPTL has informed in the early

morning (02:47 Hrs and 07:09 Hrs) that Line is healthy and it is ready to charge as abnormality

observed during patrolling. On all the three occasions trial charging was attempted from

Teesta3 end by ERLDC and fault persisted.

3. Issue of Non-Availability of Offline fault locator at Teesta 3 and Kishanganj substation: The

non-availability of off line fault locator at both ends resulted in delay in finding the exact location

of conductor snapping which has led to delay in the restoration activities.

4. Issue of Large angular separation and Power swing in Sikkim Hydro Complex: Based on the

analysis of event, it is observed that in case of only 400 kV Teesta3-Kishanganj and Rangpo-

Kishanganj and N-1 of other circuit will result in power swing on the other circuit. In present case

the angular separation has increased to more than 59 degrees between Rangpo-Kishanganj

circuit and survival of the system under such condition would be difficult and system may go

under transient instability. The same need to be analysed in detail with simulation.

Protection Issues Observed:

1. Backup Overcurrent Protection at Kishanganj for 400 kV Rangpo-Kishanganj circuit: This

protection should have been in disabled condition in the circuit and line should not have tripped.

2. SPS Non-Operation at Rangpo End: The SPS at Rangpo end did not operate as the time delay has

ben set as 900 msec however the system got islanded due to tripping from Kishanganj prior to

that.

3. SPS Non-Operation at Teesta 3 End: At Teesta 3 end Cable Overload protection-based Unit

tripping is implemented which trip one unit after 1.5 second delay. However, no additional

scheme is implemented if the Cable overloading persisted for large duration of time even after

one-unit tripping at Teesta 3. This can be the situation if any of the SPS at other end did not

operate successfully. This issue was observed on the 16-04-19 at 23:32 Hrs where the 400 kV

Rangpo-Kishanganj circuit tripped on Direction earth fault and SPS did not operate at Rangpo

end. During this situation, whole Sikkim hydro has evacuated through 400 kV Teesta3-Kishanganj

circuit which led to cable overloading. During this event, voltage at Teesta 3 dropped to 360 kV

and after five minutes, 4 Units at Teesta3 tripped on Minimal impedance stage -2 protection

operation and thus reducing the cable loading below 2000 Amp.

4. A/R operation at Rangpo end on 400 kV Rangpo-Kishanganj circuit: It is observed that the

current persisted in the Y phase pole at Rangpo end even though the Y phase Pole at Kishanganj

end has opened indicating development of fault in the circuit.

5. SOTF non-Operation at Teesta3 end during Trial attempt: SOTF was not operating at Teesta3

circuit while trial charging of 400 kV Teesta 3-Kishanganj end as the fault current during trial

charging was around 2.8-2.9 kA and SOTF setting is at 3 kA. In addition, Main 1 relay at Teesta 3

has picked the fault in zone 1 while main 2 in zone 2 and only main 2 relay has given the tripping

command which was not desirable.

6. Tripping of 400/132 kV ICT at Dikchu during Fault: 400/132 kV ICT at Dikchu end is tripping on

backup overcurrent protection instantaneously which was not desirable.

7. Over-frequency setting for Sikkim Hydro Complex: The over frequency setting for all the Hydro

generation in Sikkim is having varied setting which may be kept uniform in case of unintentional

islanding. The setting for all the six hydro generators is given below:

Generator Over frequency trip ROCOF Under Frequency Trip

Dikchu 51.8 Hz -20 sec. 65 Hz -100 ms

Nil 48.30 Hz -10 sec. 47.3 Hz -1 sec

Chujachen 52.6 Hz -40 sec. 68 Hz -20 ms

Nil 48.30 Hz -10 sec. 47.3 Hz -1 sec

Teesta 5 52 Hz- 5 Sec 55 Hz-3 sec

Tashiding 51.8 Hz -20 sec. 65 Hz -100 ms

Nil 48.30 Hz -10 sec. 47.3 Hz -1 sec

Teesta 3 51.5 Hz-3 Sec 52.5 Hz-1 Sec

48.5 Hz- 3 sec 47.4 -1 sec

Jorethang 51.8 Hz -20 sec. 65 Hz -100 ms

8. DR Configuration at Kishanganj end: The DR shared from Kishanganj end were not having

adequate digital status configured for the circuit. This is highly undesirable and make it difficult

to analyse the event and finding the root cause of tripping.

Suggested Course of Action for Improvement of System Reliability

1. Checking of Protection setting and Logic at Kishanganj Substation and Carrying out a joint third-

party Protection Audit. (PGCIL ERTS 1)

2. There is a need to analyse the issue of A/R operation at Rangpo end during this event as it seems

that one more fault has developed in the Rangpo-Kishanganj circuit. This can be due to clearance

or sag issue due to high current flowing through circuit after tripping of another circuit. (PGCIL

ERTS 2)

3. Ensuring the availability of Offline Fault Locator at all substations and with all ISTS licensee to

find the exact location of the fault (TVPTL at Kishanganj and Teesta3 end)

4. Proper maintenance of the Newly constructed Quad Circuit by TVPTL: One conductor snapping

event on 400 kV Teesta3-Kishanganj circuit (12-04-19) and two Fault events on 400 kV Rangpo-

Kishanganj circuit (14-04-19 and 16-04-19) has already occurred on the lines of TVTPL. Patrolling

at regular interval in addition to clearance of RoW needs to be done at regular interval specially

with onset of high hydro in Sikkim hydro complex. (TVPTL)

5. Proper information dissemination and Patrolling as three charging attempts taken on the faulty

line and all have failed even after confirmation of healthiness of line from ISTS licensee is not

desirable in view of grid security and restored system. (TVPTL).

6. Dikchu ICT tripping is not correct for through fault in the system. Dikchu is advised toc heck the

relay setting. (Dikchu)

7. As the Sikkim Hydro complex would be evacuating through only four circuits (400 kV Rangpo-

Kishanganj & 400 kV Teesta3-Kishanganj Quad Moose and 400 kV Rangpo-Binaguri (Twin moose

circuit. The thermal overload limitation for quad moose circuit are 1385 MVA (Due to Cable

section rated at 2000 Amp) and Twin moose circuit are 874 MVA. In addition, the issue of high

resistance fault on these circuits due to hilly terrain followed by N-2 contingency issues being

double circuit tower poses as a challenge to the system reliability and security. The N-2

contingency on Quad Moose circuits with limitation of Angular stability in existing network

configuration and voltage drop due to long haulage of high amount of power also is a cause of

concern. Thus, it is advisable that for the upcoming hydro season a suitable SPS scheme need to

be implemented to ensure the system reliability with various contingencies.

8. There is a need to coordinate for over frequency stage 1 and 2 setting for Sikkim hydro so that in

case of system islanding, the chances of survival of units can be enhanced.

DR Analysis: Kishanganj End

1. 400 kV Teesta 3- Kishanganj DR (Main 2 REL 670)

Trigger12-04-2019

23:55:11.435

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

LINE_A_IL1/kA

0

2

4

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

LINE_A_IL2/kA

0

2

4

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

LINE_A_IL3/kA

0

2

4

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

LINE_A_IN/kA

0

2

4

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

LINE_UL1/kV

0

50

100

150

200

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

LINE_UL2/kV

0

50

100

150

200

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

LINE_UL3/kV

0

50

100

150

200

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

LINE_UN/kV

0

50

100

150

200

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

//LINE M CTN/kA

0

2

4

t/s-0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

FLT_LOOP_BphFLT_LOOP_YphFLT_LOOP_Rph

TRIP_TRIPM1_PTN_OPTD

DTR_CH-1&CH-2TIE_CB_BPH_OPTIE_CB_YPH_OPTIE_CB_RPH_OP

M2 CSBI_ZCOM-CR

ENABLE STUBM2 BB UNIT FA

CB OPEN BCB OPEN YCB OPEN R

AR_OPTDGR-B DC FAIL

CF CH-1CR CH-2CR CH-1

TIECB_TR L3TIECB_TR L2TIECB_TR L1

TIECB_GEN_TRFUSE_FAIL

BI_BB_OPTDGEN_TRIP

TOV2_STARTTOV2_TRIP

TOC2_STARTTOC2_TRIP

TEST_MODE_ONSTUB_TRIP

TOV1_STARTTOV1_STG2TOV1_STG1

TEF1_STARTTEF1_TRIP

TIE_86_OPTDZCOM_CS

ZCOM_TRIPPHS-STFWPEPHS-STFWL3PHS-STFWL2PHS-STFWL1

PSB_OPTDSOTF_TRIP

ZM05-STARTZM05-TRIP

ZM04-STARTZM04-TRIP

ZM03-STARTZM03-TRIP

ZM02-STARTZM02-TRIP

ZM01-STARTZM01-TRIP

MAINCB_TR L3MAINCB_TR L2MAINCB_TR L1

MAINCB_GEN_TR

2. 400 kV Rangpo- Kishanganj DR (Main 2 REL 670)

Trigger12-04-2019

23:55:11.733

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

LINE_A_IL1/kA

0

1

2

3

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

LINE_A_IL2/kA

0

1

2

3

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

LINE_A_IL3/kA

0

1

2

3

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

LINE_A_IN/kA

0

1

2

3

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

LINE_UL1/kV

0

100

200

300

400

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

LINE_UL2/kV

0

100

200

300

400

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

LINE_UL3/kV

0

100

200

300

400

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

LINE_UN/kV

0

100

200

300

400

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

//LINE M CTN/kA

0

1

2

3

t/s0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

FSD1-BLKUDTR_CH-1&CH-2TIE_CB_BPH_OPTIE_CB_YPH_OPTIE_CB_RPH_OP

BI_ZCOM-CRG_TIE_86_TRIPG_MAIN_86_TRI

ENABLE STUBDTR_CH-1

DT SEND CH-1CB OPEN BCB OPEN YCB OPEN R

AR_OPTDCF CH-1CR CH-2CR CH-1

FUSE_FAILBI_BB_OPTD

GEN_TRIPTOV2_START

TOV2_TRIPTOC2_START

TOC2_TRIPSTUB_TRIP

TOV1_STARTTOV1_STG2TOV1_STG1

TEF1_STARTTEF1_TRIP

TIE_86_OPTDZCOM_CS

ZCOM_TRIPPHS-STFWPEPHS-STFWL3PHS-STFWL2PHS-STFWL1

PSB_OPTDSOTF_TRIP

ZM05-STARTZM05-TRIP

ZM04-STARTZM04-TRIP

ZM03-STARTZM03-TRIP

ZM02-STARTZM02-TRIP

ZM01-STARTZM01-TRIP

MAINCB_TR L3MAINCB_TR L2MAINCB_TR L1

MAINCB_GEN_TR

DR Analysis: Rangpo End

1. 400 kV Teesta 3- Kishanganj DR

Trigger12-04-2019

23:55:12.318

t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

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 3.5

VB/kV

50

100

150

200

t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

VC/kV

50

100

150

200

t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

VN/kV

0

100

200

t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

IA/kA

0

1

2

3

t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

IB/kA

0

1

2

3

4

t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

IC/kA

0

1

2

3

t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

IN/kA

0

1

2

3

4

t/s-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

IN>1 TripPower Swing

DIST Trip CDIST Trip B

DIST Start CDIST Start BDIST Start A

Relay 9Relay 15

Relay 2DEF Fwd

SOTF/TOR TripZ4Z3Z2Z1

LBB OPTDBB OPTD

Power SwingV>2 TripV>1 Trip

Virtual Input 1GR-A RLY OPTD

DT RECVD-2DT RECVD-1

M-2 CARR RECVDCARR RECVD-1

M-2 RLY HEALTHYAny Trip

M CB B OPENM CB Y OPENM CB R OPEN

DR Analysis: Teesta 3 End

1. 400 kV Teesta 3- Kishanganj DR (tripping 23:55 hrs on 12-04-19)

2. 400 kV Teesta 3- Kishanganj DR (Trial Charging 01:15 hrs on 13-04-19)

Trigger12-04-2019

23:55:11.439

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VA/kV

0

50

100

150

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VB/kV

0

50

100

150

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VC/kV

50

100

150

200

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VN/kV

0

100

200

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IA/kA

0

1

2

3

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IB/kA

0

1

2

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IC/kA

0.00

0.25

0.50

0.75

1.00

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IN/kA

0

1

2

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

Z1CB Close B Ph.CB Close Y PhCB Close R Ph

CB OpenDIST Sig. Send

DIST Trip CDIST Trip BDIST Trip ADIST. COS

Trigger13-04-2019

01:15:03.743

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VA/kV

0

50

100

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VB/kV

0

100

200

300

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VC/kV

0

50

100

150

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VN/kV

0

200

400

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IA/kA

0

1

2

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IB/A

0

50

100

150

200

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IC/A

0

100

200

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IN/kA

0

1

2

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

Z1

CB Close B Ph.

CB Close Y Ph

CB Close R Ph

CB Open

DIST Sig. Send

DIST. COS

3. 400 kV Teesta 3- Kishanganj DR (Trial Charging 03:40 hrs on 13-04-19)

Trigger13-04-2019

03:40:56.017

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VA/kV

0

50

100

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VB/kV

0

50

100

150

200

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VC/kV

0

50

100

150

200

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

VN/kV

0

25

50

75

100

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IA/kA

0

1

2

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IB/A

0

200

400

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IC/A

0

100

200

300

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

IN/kA

0

1

2

t/s-1.5 -1.0 -0.5 -0.0 0.5 1.0 1.5

Z1

CB Close B Ph.

CB Close Y Ph

CB Close R Ph

CB Open

DIST Sig. Send

DIST. COS

DR Analysis: Dikchu

1. 400/132 kV ICT

Trigger12-04-2019

23:55:12.226

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

VA/kV

20

40

60

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

VB/kV

20

40

60

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

VC/kV

20

40

60

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

IA/A

0

200

400

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

IB/A

0

200

400

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

IC/A

0

200

400

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

IN/A

0

100

200

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

IN Sensitive/mA

50

100

150

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

Frequency/Hz

10

20

30

40

t/s-0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

UnusedUnusedUnusedUnusedUnusedUnusedUnusedUnusedUnusedUnusedUnusedUnused

Trip Command InIN1>2 TripIN1>1 Trip

I>2 TripI>1 TripInput L8Input L7Input L6Input L5Input L4Input L3

LINE CHARGINGInput L1

50BF TO BBOutput R6Output R5

TCS WAY2TO 86L2 MT

67N TO CONTR.67 TO CONTROLLER

Event Logger: Kishanganj

Event Logger: Jorethang (Unit 2)

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

400KV BINAGURI-TALA-I 01-04-2019 0:23 DT received at Binaguri DT received at Binaguri -- No Fault observed in PMU

220KV PUSAULI-DEHRI-SC 03-04-2019 13:55 03-04-2019 14:29 Z-1 C-N,50.08 km, Ia 277.5 A, Ib 315.5 A Ic 2.138 kA

-- No Fault observed in PMU

400KV GORAKHPUR-MOTIHARI-I 06-04-2019 21:45 07-04-2019 10:17B -N,127.2 KM ,2.9 KA FROM

GORAKHPUR AND MAIN 2 RELAY 171.4 KM AND 2.5 KA

B-N,4.87 KA FROM MOTIHARI; ATTEMPTED AT 22:35 HRS B-N 5.96 KA 18.44 KM IN MAIN 2 FROM MOTIHARI

B-N Fault -- No Fault observed in PMU

400KV NEW PPSP-NEW RANCHI-I 08-04-2019 9:43 08-04-2019 9:58 Not tripped DT received DT received -- No Fault observed in PMU

220KV ARRAH-NADHOKHAR-SC 17-04-2019 8:07 18-04-2019 7:11 TRIPPED FROM NADOKAR END ONLY

TRIPPED FROM NADOKAR END ONLY

-- No Fault observed in PMU

220KV TENUGHAT-BIHARSARIFF-SC 04-04-2019 12:45 29-04-2019 17:10 Z1 R-N,97,86 KM,1.357 KA 90 KM FROM BSF, ATTEMPTED FROM

13:27 HRS AND TRIPPED IMMEDIATELYR-N Fault < 100 msec No A/R operation

400KV KISHANGANJ-NEW PURNEA-II 06-04-2019 16:45 06-04-2019 17:01 Y-n, 19.17 km, 7.963 kA A/R: Y-n, 74.2 km, 5.54 kA Y-N Fault < 100 msec No A/R operation

220KV BARIPADA-BALASORE-II 08-04-2019 6:56 08-04-2019 7:36 B-N,Z-1, FD 51.86 Kms, FC :- 3.079 K

B-N,Z-1, FD 12.03 KMs, FC :- 4.49 KA B-N Fault < 100 msec No A/R operation

400KV MOTIHARI-GORAKHPUR-1 08-04-2019 11:12 08-04-2019 11:38 B-N,5.19KA,17.89 KM NO TRIPPING AT GORAKHPUR END B-N Fault < 100 msec No A/R operation400KV DURGAPUR-SAGARDIGHI-I 09-04-2019 15:04 09-04-2019 16:00 B-N 4.128 KA, 1.101 KM DP Z-1,B-N,12.68km,13.98 KA B-N Fault < 100 msec No A/R operation

220KV PUSAULI-SAHUPURI-SC 12-04-2019 11:57 12-04-2019 13:33 Z-1,B-N,2.974 KA ,52 KM FROM PUSAULI

B-N Fault < 100 msec No A/R operation

400KV KHARAGPUR-KOLAGHAT-I 15-04-2019 12:42 15-04-2019 13:01 KGP end:- B Ph, Z-2, 86 Km, 3.14 KA

KTPP:- B Ph , Z-1 , 7.km, 14.12KA B-N Fault < 100 msec No A/R operation

400KV ANGUL-JITPL-II 18-04-2019 21:25 18-04-2019 22:07 R-N,47.52 KM FC 7.54KA R-N,27.3KM,FC R-N Fault < 100 msec No A/R operation

220KV CHANDIL-RAMCHANDRAPUR-SC 19-04-2019 1:27 19-04-2019 2:32 Chandil: BN, 4.928 KA, Z1, 12.06 KM

B-N Fault < 100 msec No A/R operation

220KV STPS(WBSEB)-CHANDIL-SC 19-04-2019 1:27 Tripped from Chandil end only B-N Fault (as per PMU) < 100 msec No A/R operation

400KV PUSAULI(PG)-VARANASI-SC 22-04-2019 11:57 22-04-2019 13:02 Y-N, 143KM, 2.29KA Y-N Fault < 100 msec No A/R operation

400KV DARBHANGA (DMTCL)-KISHANGANJ(PG)-II 23-04-2019 7:07 23-04-2019 7:43 73 km from kishanganj b-n from darbhanga,119.1 km,2.8 ka B-N Fault < 100 msec No A/R operation

765KV JHARSUGUDA-ANGUL-IV 24-04-2019 14:29 24-04-2019 18:45 B-N, Z-1, 1KM FROM ANGUL , F/C-18KA

B-N, Z-1, 220KM FROM JHARSUGUDA, F/C-18KA

B-N Fault < 100 msec No A/R operation

220KV PUSAULI-SAHUPURI-SC 25-04-2019 12:03 25-04-2019 13:14 B-N, 7.9 KA, 9.02 km from Pusauli

B-N Fault < 100 msec No A/R operation

220KV PUSAULI-SAHUPURI-SC 25-04-2019 14:02 25-04-2019 15:42 B-N.7.9 KA,9.01 KM Z-1FROM SASARAM

B-N Fault < 100 msec No A/R operation

400KV DARBHANGA (DMTCL)-KISHANGANJ-I 25-04-2019 22:12 25-04-2019 22:30 A/R successful at kinshanganj B-N Fault (as per PMU) < 100 msec No A/R operation

220KV NEW PURNEA-MADHEPURA-DC 25-04-2019 22:12 25-04-2019 23:00 TRIPPED FROM MADHEPURA END ONLY

B-N Fault (as per PMU) < 100 msec No A/R operation

400KV KISHANGANJ-RANGPO-I 26-04-2019 14:31 26-04-2019 15:05 CB REMAIN CLOSED AT RANGPO IR 0.22 KA IY 0.65 KA IB =0.34 KA AT KISHANGANJ

B-N Fault (as per PMU) < 100 msec No A/R operation

220KV BUDHIPADAR-RAIGARH-SC 27-04-2019 12:25 27-04-2019 14:11 11.9 KM ,Z1,2.93 KA B-N, 68 KM FROM RAIGRAH, 1.3 KA. B-N Fault 500 msec No A/R operation

400KV RENGALI-KEONJHOR-SC 28-04-2019 11:19 B-N,45.14 KM,2.187 KAB-N,65.2 KM 1.82 KA ;ATTEMPTED AT 12:03 HRS CUD NOT HOLD,Z1 B-N,2.19

KA Z1B-N Fault < 100 msec A/R unsuccessful,Multiple

A/R attempt

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 April 2019 where violation of protection standard has been observed

Annexure-B8

Sl No.

Name of the incidence PCC Recommendation Latest status

78th PCC Meeting

1. Disturbance at 400 kV Lapanga(OPTCL) S/s on 14.03.2019 at 13:39 Hrs

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.

2. Disturbance at 400 kV Lapanga(OPTCL) S/s on 15.03.2019 at 11:59 Hrs

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.

77th PCC Meeting

3. 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.

4. 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.

5. 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

6. 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

ANNEXURE-C6

to analyze the reasons behind failure of the islanding scheme during this disturbance

7. 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.

8. 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

9. 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

74th PCC Meeting

10. 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

11. 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

12. 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.

13. 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

NTPC informed that the carrier

Kahalgaon and non-operation of Autorecloser.

healthiness will be checked at next

available shutdown.

68th PCC Meeting 14. 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.

15. 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.

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-C8

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

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)

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-C12

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