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SOUTHERN REGIONAL POWER COMMITTEE BANGALORE

Minutes of the 37thMeeting of

Protection Coordination Sub-Committee Of SRPC held on 30.10.2014

1 Introduction The 37th Meeting of Protection Coordination Sub-Committee (PCSC) was held on 30thOctober

2014 in the Conference Hall of Southern Regional Power Committee, Bangalore. The list of

participants in the PCSC meeting is enclosed as Annexure-I.

Shri S. R.Bhat, Member Secretary (MS), SRPC welcomed the Members and participants to the Meeting. The following points were highlighted by MS, SRPC.

Number of transmission lines had tripped during Hudhud cyclone in the coastal districts Visakhapatnam, Sirkakulam, and Vizianagaram of Andhra Pradesh. The analysis in this regard was to be made.

PSAG-9 was conducted at Srisailam Right Bank Power House on 14th and 15th of October, 2014 to address the grid disturbances at SRBPH.

o PSAG-9 and APGENCO participation and contribution was placed on record. o Follow up actions as recommended need to be carried out in a timely manner.

Segregation of Feeders for SPS schemes between Andhra Pradesh and Telangana state need to be completed.

Most of the utilities had submitted DPR to NLDC for PSDF funding. They had also submitted affidavit to CERC in respect of phase-I & II activities seeking extension of time to carry out protection audit recommendations.

Protection System Analysis Group (PSAG) visit to Kadra, Kodasalli and Kaiga was planned on 12th and 13th November 2014 to discuss the grid incidents happened there.

2 Confirmation of the Minutes of the 36th PCSC Meeting held on 30-09-2014

Minutes of the 36th PCSC meeting were confirmed since no comments had been received from the constituents.

3 Grid Disturbances (GD) in the Southern Region 3.1 GD-1 at Kadra and Kodasalli hydro power station (i) Date and Time of Event 26-09-2014 at 15:50 hrs

(ii) Location Kadra and Kodasalli, Karnataka

(iii) Plant and/or Equipment directly involved

Kadra and Kodasalli hydro power stations of KPCL.

(iv) Reported Disturbance / Fault

De-energization of 220kV bus occurred at Kadra and Kodasalli hydro power station due to tripping of 220kV lines. B-Phase to earth fault had occurred in 220kV Kadra-Kodasalli line. Distance protection at Kadra

Minutes of the 37th Protection Coordination Sub Committee Meeting held on 30.10.2014 Page 2

end had sensed the fault in Zone-1 and cleared the fault from Kadra end. At Kodasalli end, back up earth fault and over current had operated

(v) Generation Loss 38 MW (at Kodasalli)

(vi) Category GD-1

Deliberations: PCSC forum decided to investigate the disturbance further. It was agreed that Protection System Analysis Group (PSAG-10) would visit Kadra , Kodasalli and Kaiga Power Houses .

3.2 GD-1 at Kadra and Kodasalli hydro power station

(i) Date and Time of Event 05-10-2014 at 17:22 hrs

(ii) Location Kadra and Kodasalli , Karnataka


Kadra and Kodasalli hydro power stations of KPCL.


De-energization of 220kV bus occurred at Kadra and Kodasalli hydro power station due to tripping of 220kV lines. Zone-2, B-phase had operated at Kaiga end for 220kV Kaiga-Kodasalli and 220kV Kaiga-Kadra lines


(vi) Category GD-1

Deliberations: PCSC forum decided to investigate the disturbance further. It was agreed that Protection System Analysis Group (PSAG-10) would visit Kadra , Kodasalli and Kaiga Power Houses on 12th and 13th November , 2014.

3.3 GD-1 at Kadra and Kodasalli hydro power station

(i) Date and Time of Event 14-10-2014 at 15:18 hrs

(ii) Location Kodasalli , Karnataka


Kodasalli hydro power station of KPCL.


De-energization of 220kV bus occurred at Kodasalli hydro power station due to tripping of 220kV lines. Generation loss was 74 MW. Two running units tripped.


(vi) Category GD-1


Deliberations: PCSC forum decided to investigate the disturbance further. It was agreed that Protection System Analysis Group (PSAG-10) would visit Kadra, Kodasalli and Kaiga Power Houses on 12th and 13thNovember, 2014.

Recommendations and follow up: Subsequently the Meeting of the Protection System Analysis Group (PSAG-10) was held at Kadra, Kodasalli (KPCL) and Kaiga (NPCIL) Powerhouses and the switch yard on 12th and 13th November, 2014.The recommendations are attached with the Minutes as Annexure.

4 Grid Incidences (GI) in the Southern Region

The Grid Incidences that had occurred during the period of September – October, 2014 were discussed in the PCSC meeting. Details (deliberations and recommendations) of the Meeting are enclosed herewith as Annexure-II.

5 Islanding Schemes in the Southern Region

Deliberations:

Complete Islanding Scheme as approved by PCSC is enclosed as Annexure-III.

NLDC had found out that during September -2014, due to Opening of ER-SR Interconnector, Talcher Stage –II had formed an island with HVDC connection of Talcher-Kolar Link.

NTPC had informed that no Sub Synchronous Resonance was noticed during Islanding.

NTPC was requested to revert back on this issue and possible Islanding Scheme for Talcher Stage-II in the next Meeting of PCSC.

6 Compliance Measures with regard to orders of Hon’ble CERC

6.1 Petition No. 146/MP/2013 with I.A. 36/2013 Order dated 20.02.2014 Deliberations & Follow up:

In the PCSC meeting, timely compliance of the above orders was highlighted. Periodicity of Reporting was also discussed and the constituents were requested to kindly submit the progress of implementation to SRPC and SRLDC as specified in the Order dated 20th February, 2014 of Hon'ble CERC.

Issue regarding non-furnishing of FIR / Trip Analysis Report, EL, DR, etc. was also highlighted. SRPC vide letters dated 8thOctober and 20thOctober 2014 had taken up the issue under Clause 1.5 of IEGC. It was pointed out that the above reports are to be submitted / uploaded on SRLDC web application within 24 hours as mandated under IEGC / CEA Regulations.

Recommendations

a. All the constituents were requested to kindly submit the updated status of the compliance (those who have not completed recommendations mentioned in the Phase I and Phase II) to SRPC Secretariat at the earliest .


b. The following constituents are to submit the updated status of filing of

petition/affidavit to SRPC Secretariat at the earliest: (i) APTRANSCO (ii) TSGENCO (Hydro & Thermal)

6.2 Petition No. 167/Suo- Motu/2012

Petition No. Order/ROP Date

Order Description Report to be submitted by respondents.

Periodicity of Reporting to CERC

167/Suo-Motu/2012 O : 22.02.2014

RPCs shall ensure that the approved philosophy is adopted by all users.

SR Constituents As and when

167/Suo-Motu/2012 O : 22.02.2014

We direct ISTS licensees to submit details of updated distance protection relay setting of all inter-regional lines with POSOCO & RPCs.

PGCIL & ISTS Licensee latest by 04.04.2014

To be collected

167/Suo-Motu/2012 O : 22.02.2014

The Commission directs all SLDCs to install/activate sound recording system in their control rooms within three months from the date of issue of this order.

SLDCs To be followed

Deliberations:

In the PCSC meeting, timely compliance of the above order was highlighted.

Periodicity of reporting was discussed and the constituents were requested to submit the progress of implementation to SRPC and SRLDC as specified in the Hon'ble CERC Order dated 22.02.2014.

6.3 Petition No. 263/MP/2012

Petition No. Order/ROP Date

Order Description Report to be submitted by respondents.

Periodicity of Reporting to CERC

263/MP/2012 O : 19.12.2013

SRLDC and SRPC of implementation of quantum of relief by AUFR as per table above and proper functioning of df/dt relays within one month of issuing this order.

Certified copy sent to SR constituents

-

263/MP/2012 O : 19.12.2013

SLDCs are directed to map these relays on the SCADA system within three months of issuance of this order. SRPC/SRLDC shall submit a compliance report in this regard

CERC Before 19.04.2014


within four months of issuing this order.

Deliberations:

In the PCSC meeting, timely compliance of the above order was highlighted.

Periodicity of Reporting was discussed and the constituents were requested to submit the progress of implementation to SRPC and SRLDC as specified in the Hon'ble CERC Order dated 19.12.2013.

7 Implementing / Reviewing the Special Protection Schemes (SPS)

I. Kolar HVDC run back SPS

PGCIL: In view of additional line coming up in S1-S2 region, the SPS may become redundant in

next six month.

SRPC /SRLDC: The load demand in S2 region will also go up. There may not be any reduction in power flow in 400 KV Kolar- Hosur D/C since

purchases by S2 constituents may also go up with Economical Despatching. In the past it has been seen that More than one Element trips on fault which may lead to

worst possible contingency, and at that time SPS may play an important role. Recommendation

PCSC forum requested PGCIL, SRTS II to implement the proposed SPS scheme at the earliest.

II. Review of Nagjheri SPS. Deliberations:

KPTCL: The details of the revised scheme as submitted by KPTCL are enclosed herewith as

Annexure-IV. Recommendation

SRPC, Secretariat in consultation with SRLDC will review the proposal.

8 The issue of quantum of df/dt relief in SR

TANTRANSCO vide letter No. CE/O/CNI/SE/LD &GO/EE/F/D/526/14 dt20.08.2014 had requested to continue with the existing df/dt settings and the settings may be reviewed after taking a final decision on uniform settings.

Deliberations: Member Secretary, SRPC informed that the issue had been put up to National Power Committee (NPC) and the SR settings would be reviewed after the decision is taken at NPC level.


9 Status of Pending Protection issues Pending protection issues were discussed in the Meeting. The constituents were requested

to send /update the recommendations of the previous PCSC meetings on or before the next PCSC.

It was decided in the meeting that the previous recommendations would be circulated to then constituents and they would update the compliance status.

The follow up issues would be discussed before taking up the other agenda items.

Recommendation& Follow up PCSC recommendations from 30th PCSC to 36th PCSC were circulated to the

constituents vide SRPC e–mail dt 30.10.2014. Constituents were requested to send the status of compliance latest by 25.11.2014.

10 Submission of completed dynamic study data

All SLDCs were requested to direct the embedded IPPs connected at 220 kV and above voltage level to submit completed dynamic study format to SRPC, Secretariat.

Deliberations Constituents were requested to submit the Dynamic study data at the earliest.

11 Informing configuration changes to PCSC forum

It had been agreed in the PCSC forum that any change in the system configuration ( i.e. addition of Generating Units, Capacitors, Reactors, LILO etc) would be highlighted and brought to attention of the forum during PCSC Meetings .

This would enable utilities to review their protection settings and to have better protection coordination in the Southern Region.

All constituents were requested to submit the change in the configuration in their system if any to the PCSC forum on a monthly basis.

12 Special / Sub Group Meetings of PCSC held in the month of November 2014.

PSAG-10 was held on 12th and 13thNovember, 2014 at Kadra , Kodasalli(KPCL) and Kaiga (NPCIL ) Power Houses / 220 KV Switch Yards,to discuss the Grid Disturbances that occurred during September – October 2014 in the Kadra, Kodasalli Power Houses.The Minutes of the PSAG-10 Meeting is enclosed herewith as Annexure–V.

Recommendations KPCL and KPTCL were requested to kindly update the steps/action taken to implement the PSAG-10 recommendation (to avoid the similar Grid disturbances) on or before the next PCSC.

13 Data as requested by NLDC/SRLDC

The constituents were requested to submit the details as requested as per Annexure-VI in all 220 KV and above Substations /Transmission elements at the earliest.


14 Follow up actions of Previous PCSC recommendations

The Follow up discussion of Previous PCSC recommendation is enclosed herewith as Annexure-VII.

15 Date & Venue of the next Meeting

39th PCSC meeting would be conducted on 30.12.2014 (Tuesday) in SRPC, Bangalore.

*****

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ANNEXURE I (1/5)

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ANNEXURE I (2/5)

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ANNEXURE I (3/5)

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ANNEXURE I (4/5)

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ANNEXURE I (5/5)

ANNEXURE - II

1

The following tripping on account of various faults, over voltage condition, and non-operation of auto-reclose scheme were discussed in the 37th PCSC:

I. GRID INCIDENTS (GI)

S. No.

Details of Events

Date and Time

Reason Category

1 Tripping of 400/220kV ICT-1 & ICT-2 at 400kV Warangal substation

18-09-2014on 21:01 hrs

ICT’s tripped due to operation of Directional Earth Fault relays on 400 KV side of ICT 1 &2. It was informed that fault had occurred in downstream 220kV system. From D.R of ICT’s fault ampere of 2kA and 2.7kA in R phase was observed for ICT-1&2 respectively. The tripping need further analysis as the fault current was not high to operate the High set of earth fault relay and there was no delayed clearance of fault in 220kV system.

GI- 2

KHAMMAM400kV BUS I

400 kV BUS

ICT I ICT II

220 kV BUS I

220 kV BUS

TRANSFER BUS

NGRM I II

RMG

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(1/16)

ANNEXURE - II

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Deliberations: SRLDC:

High set instantaneous protection operated for ICT. Fault was on downstream 220 kV side near the station bus close to Ngrm.

line. Earlier electro mechanical relay meant for high set operation used to operate

instantly and now numerical relay is set with 100ms delay. Recommendations:

PGCIL is requested to send trip analysis indicating the cause of high set operation despite not very high fault current.

2 Tripping of 400kV Bus-1 and 400kV Ramagundam-Nagarjunasagar line

19-09-2014 at 12:44 hrs

LBB protection of 400kV Ramagundam-N’sagar line had mal-operated due to spurious initiation from 86 trip relay which caused tripping of 400kV Ramagundam-N’sagar line and direct trip to remote end. Along with this LBB initiated 400kV Bus-1 trip which resulted in tripping of all the breakers connected to Bus-1 at Ramagundam station. Remedial actions taken may be furnished to PSC

GI-2

Deliberations: NTPC:

At Ramagundam end, the 86 relay (VAA) contacts meant for LBB relay (CTIG) of Nagarjunasagar line became bridged and initiated LBB. This

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ANNEXURE - II

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resulted in opening of all main CBs connected to Bus-1 and some tie-CBs of the dia (i.e. at Ramagundam, the 400 kV bus is with one and half CB scheme).

A DT signal was sent to Nagarjunasagar remote end and the CB was opened there.

The contacts of 86 relay became bridged due to ageing factor. The LBB scheme is a single stage, and there is no retrip before LBB

initiation. The faulty contacts have been replaced now.

Recommendations:

NTPC is requested to explore the possibility of including re-trip feature in the LBB relay before actual LBB initiation.

3 Tripping of 400kV Raichur-Mahboobnagar line

20-09-2014 at 22:34 hrs

line tripped at Raichur end only due to operation of carrier lock out relay

GI-2

Deliberations:

It is noted that carrier lock out is due to inadequate battery power for the PLCC systems.

KPCL: Battery system procurement is under way.

Recommendations:

KPCL is requested to expedite the process of installing adequate DC batteries for PLCC system.

Rajan

(3/16)

ANNEXURE - II

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4 765/400 kV ICT-3 at NPS

22-09-14 at 7:48 hrs

FIR, D.R, E.L not submitted. As per verbal information L.A failure had caused tripping of ICT

GI-2

Deliberations: Pre-fault conditions:

Two ICTs (765/400 kV) were in operation. Gooty (2 lines), Nellore (2 lines), TPCIL (2 lines), SEPL (1 line), and

MEPL (1 line) lines were in operation. Bus reactors were in operation on both 765 (2x245 MVAR) 739 kV and 405

kV sides. PGCIL:

Differential protection of ICT-3 operated due to the failure of 400 kV B-phase lightning arrester (LA) whose location is covered by the differential zone of the ICT.

The LA is not old and new one and the LA got split due to the fault. Though DR has been commissioned, DR data could not be recovered.

Recommendations: a. As despite normal voltage at 400 kV bus, new LA and bus reactors in

service, the failure of LA shall be investigated by PGCIL and a report shall be sent to the PCSC forum.

b. Efforts shall be made to retrieve the DR data pertaining to the differential operation and the retrieved data shall be sent to PCSC forum.

c. Equipment failure report for 400 kV LA shall be sent to SETD division of CEA, New Delhi.

Gooty

Nellore

TPCIL

SEPL

MEPL

765 kV 400 kV

ICT-3 3x500 MVA

LA

245 MVAR

245 MVAR

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ANNEXURE - II

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5 220kV Ambewadi-Ponda line

25-09-2014 at 12:54 hrs

As per FIR line was hand tripped due to 220/110kV Bus dead. Reason for bus de-energization may be furnished to PSC

GI-1


As Ambewadi - Narendra (D/C) line was under maintenance and CBs at both end were open, Ambewadi was fed in radial from Nagjheri.

There was no distance protection at Ambewadi end. KPTCL:

25 km from Nagjheri, there was a fault on 220 kV Ambewadi line-2 At Nagjheri end, Ambewadi line-2 CB was tripped on zone-1protection, and

Ambewadi line-1 CB was tripped on zone-2 protection. At Ambewadi end, Nagjhari-2 line CB was tripped by backup E/F

protection. As the feed was only from Nagjheri, the Ambewadi bus became dead.

Subsequently the Ponda-1 line was hand-tripped at Ambewadi. Earlier, on Ambewadi – Ponda line, once transient fault and once insulator

failure have occurred. Corrective actions taken :

o At Ambewadi, the faulty distance relays of NPH-1 & 2 lines are replaced bynew distance relays.

o DEFR time setting of NPH-1 & 2 lines are revised (from 0.18 to 0.1 sec).

Narendara Ponda Ambewadi

Xeldom

Goa Karnataka

Nagjhari

1 2

Z1 trip

b/u trip

Z2 trip

ANNEXURE - II

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Recommendations:

a. A trip analysis report shall be with the corrective actions for the following issues shall be sent to PCSC forum.

b. Measures for preventing Ambewadi – Nagjheri line -1 opening in case of fault on the Ambewadi – Nagjheri line -2 and vice versa.

6 Tripping of 400KV Hassan-UPCL line-2

25-09-2014 at 16:16 hrs

High resistance fault as the fault ampere was very less i.e., 0.6kA at Hassan end and nearly 0.9kA at UPCL end. Back up earth fault protection had operated at Hassan. At UPCL end the high resistance fault got converted into a R ph-B-ph fault which resulted in operation of distance protection Zone-1. The reason for non-picking up of Back up earth fault at UPCL needs investigation.

GI-2

Observations from FIR and EL output:

In UPCIL’s event logger output of Main-2 (P437) the following was noticed:

“A 25/09/2014 16:16:15.030000 449-DIST : Zone 1 starting A 25/09/2014 16:16:15.030000 450-DIST : Zone 2 starting A 25/09/2014 16:16:15.030000 451-DIST : Zone 3 starting A 25/09/2014 16:16:15.030000 452-DIST : Zone 4 starting A 25/09/2014 16:16:15.030000 453-DIST : Zone 5 starting A 25/09/2014 16:16:15.030000 454-DIST : Zone 6 starting A 25/09/2014 16:16:15.030000 455-DIST : Zone 7 starting A 25/09/2014 16:16:15.030000 456-DIST : Zone 8 starting”

It is not clear what are the zones in use.

It appears that there is a mismatch of event logger timings of Main-1 and Main-2 relays at

ANNEXURE - II

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UPCL end.

Main-1 E/L: First line: A 25/09/2014 16:16:40.817697 13-Any Start .... trip events Last line: N 25/09/2014 16:16:41.322641 5-APH AR/LBB-2 INI Main-2 E/L: First line: A 25/09/2014 16:16:14.744000 127-PSB : IN> triggered .... trip events Last line: A 25/09/2014 16:16:15.182000 332-V<> : Fault V< 3-pole

From FIR, it was noticed that there is a mismatch of timings of trip command at UPCL

and PGCIL ends: o FIR: UPCL (Main-1)

At 16:16:41.195hrs 2-Phase fault sensed for A & C-ph in Zone-1 at 71.83Kms At 16:16:41.215hrs relay issued trip command to Main(4-952) & Tie(4-852)

breakers. o FIR: PGCIL (Main-2)

E/F Start time-16:16:10:393 hrs E/F Trip time-16:16:14:695 hrs

That is zone-1 trip time (16:16:41.215hrs) of UPCL is later to the backup trip time (16:16:14:695 hrs) of PGCIL. The difference is around 23 seconds.

From the E/L outputs, it was noticed that UPCIL end sent the carrier at 16:16:15.043 hrs and it was received by PGCIL end at 16:16:15.047 and it appears to be in order.

PGCIL (E/L): U25/09/2014 16:16:15.047 HSN\400kV\407\REL_407 Carrier Receive RAISED 10035919 spontaneous UPCL (E/L Main-2): A 25/09/2014 16:16:15.043000 67-MAIN : Send transfer trip A A 25/09/2014 16:16:15.043000 68-MAIN : Send transfer trip B A 25/09/2014 16:16:15.043000 69-MAIN : Send transfer trip C

Deliberations: UPCL: There was a (R & B or A & C) fault on Hassan – UPCL line -2. As it was phase to phase fault, auto reclose did not operate. At UPCL, both main-1 (P442) and main-2 (P437) relays picked up the fault and it was

cleared by zone-1 protection. The fault was persisting for 5 seconds. Carrier was sent to Hassan end. The settings were given by KPTCL earlier. The work of reviving all settings has been given to OEM (M/s Alstom).

ANNEXURE - II

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KPTCL: At UPCL, E/F DMT settings are 0.3 A (CT: 2000/1) with 1.5 sec delay trip and then send

DT to Hassan. PGCIL:

At Hassan end,setting is 0.3 A (i.e. 3000/1 CT). At UPCL end, the settings could be 0.1 A secondary.

SRLDC:

UPCL end should have picked up the high resistance fault in back up protection before it evolved into phase-to-phase fault.

Hassan end should have sent DT to UPCL end. Recommendations:

a. At UPCL end, unused zones of distance protection (probably zone 5 to 8) shall be disabled.

b. At UPCL end, time synchronization between main-1 and main-2 relays shall be ensured.

c. UPCL shall ensure time synchronization with Hassan substation. d. Reasons for non operation of back up protection at UPCL for high resistance

fault is to be submitted. e. Reasons for not sending DT to UPCL by Hassan end is to be submitted. f. Settings of UPCL are to be reviewed and informed to PCSC forum.

7 Tripping of 400/220 kV

ICT-1 AT BTPS 27-09-2014 at 16:22hrs FIR, D.R, E.L not submitted. As

per verbal information due to problem in 220kVside

GI-2

ANNEXURE - II

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220 kV line CB at Lingapur was open. KPCL:

Lingapur line was not in service and while enabling A/R, the fault happened. During the test charging of the Lingapur line from BTPS end, zone-3 picked up and ICT

got tripped. SRLDC:

Delayed clearance of 220 kV and 400 kV lines would affect inter regional Raichur-Sholapur 765 lines and it would lead to NLDC giving notice to SRLDC and approaching CERC for remedy.

KSEB:

While charging a new radial line all settings (including earth fault current and time delay) have to be low and SOTF is to be in service.

PGCIL: At PGCIL, off-line fault locator line test for new lines is being carried out.

Recommendations:

KPCL is requested to collect DL, EL and trip analysis and submit to PCSC forum.

8 Tripping of 220kV Puducherry-Villianur and 220kV Neyveli-Villianur line

2-10-2014 at 04:25 hrs

220kV Puducherry-Villianur line -1 tripped at from Puducherry end on zone-2 and on directional O/c and E/f at Villianur 220kV Neyveli-Villianur tripped at Villianur end only on operation of directional O/C and E/f

GI-1

ANNEXURE - II

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Deliberations: PED (Puducherry Electricity Department):

No fault was there on the line. Relays were already tested by TANTRANSCO and it would be recalibrated within two

weeks time. PLCC panels also would be tested. High set relay at Villianur is set at 400% current with 0.3 sec delay.

PGCIL: At PGCIL’s 400 kV Puducherry substation, 220 kV PLCC panels are owned by PED. At Puducherry PGCIL substation, zone-2 time delay is with 0.3 sec. The fault distance

shown by the relay was 23.9 km almost at the end of the Villianur line and indicating a possible bus zone fault.

KSEB: High set relay protection is mostly used for radial feeders. High set relay settings shall include a minimum time delay of 100ms so that zone-1 of

distance protection (21) will operate first. APTRANSCO:

High set is not to be used for lines. SRDLC (ED):

As on going monsoon is there, Puducherry (PED) has to expedite the relay testing.

Recommendations: a. From Villianur substation the following shall be submitted to PCSC forum:

i. DR and EL of the event. ii. the reason for tripping of NLC TS2 line for the fault on Puducherry line.

iii. the reason for tripping the Puducherry and NLC TS2 line CBs by DEF relay. b. At Villianur substation, PED has to carry out testing of the concerned relays and review of

settings. A report in this regard shall be sent to PCSC forum.

ANNEXURE - II

11

9 Tripping of 400/220kV

ICT-1&2 at UPCL 4-10-2014 at 12:16 hrs

ICT-1&2 tripped during transient fault in R-phase in 400kV Hassan-UPCL line-1

GI-2

Deliberation: Pre-fault conditions: Unit-1 and Hassan line-2 were not in service.

UPCL: The ICTs are star-star two winding transformers with HV and LV neutrals solidly earthed. Sensitive earth fault (SEF) relay with definite time settings of 0.2A and 1 sec delay is fed

by HV neutral CT (1000/1A). There was an R-phase earth fault on Hassan line-1 and A/R picked up. During the reclaim

time of 1.0 sec of A/R scheme, ICT’s SEF on HV side picked up and both ICTs were tripped.

KPTCL:

Each ICT was drawing around 400A current prior to tripping. Recommendations:

To avoid tripping of ICTs for line fault, UPCL is requested to review the settings of ICT’s SEF relay and consider IDMT setting instead of existing Definite Time setting.

ANNEXURE - II

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10 Tripping of 400kV NPS-MEPL line

08-10-2014 at 7:04 hrs

Line tripped due to DT receive from MEPL

GI-2

Deliberation: At PGCIL/NPS: From DR output, voltage dips (Vb and Vc) and current spikes (Ib and Ic) were noticed on

phases prior to fault triggering. Phase and neutral voltages did not completely become zero even after 2 seconds of triggering.

From EL output, at 7:04:32.55 am hrs DT was received on channel-1 and channel-2. At MEPL: On DR output, voltage dips and current spikes were noticed on Line-2 and Line-3 phases

prior to fault triggering. On EL output, DT (carrier) send message could not be found. FIR details:

o Line 86A and 86B operated without any indication; o L2 & L3 phase detection elements started in Main-I relay but trip indication. o Value of fault current was 1100 A.

PGCIL: At NPS end, MEPL line CBs (main and tie) were opened after receiving DT signal from

MEPL end. At NPS end, there were no other fault indications in relation to DT receipt.

Recommendations:

a. The exact reason for receipt of DT signal at NPS end from MEPL end has to be found out and corrective measures need to be taken up by both MEPL and NPS to avoid its recurrence.

b. The forum decided to invite MEPL and SEPL whenever there is a tripping involving their power stations.

11 Tripping of 400 kV NPS

- TPCIL 2 08-10-2014 at 7:04 hrs

Line tripped at NPS end only. As per FIR, R-B phase fault had occurred in 400kV NPS-TPCIL line-1

GI-2

Deliberation: 1. From FIRs of TPCIL and NPS, the following were observed:

TPCIL and NPS are connected by two lines. There was a Y-B fault on the first line near TPCIL end (1.093 km). At TPCIL end:

o NPS line-1 CB tripped in zone-1 and sent DT to NPS remote end. o NPS line-2 CB was not opened as it sensed the fault in zone-4 (reverse).

ANNEXURE - II

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At NPS end: o TPCIL line-1 CB tripped after receipt of DT; fault distance = 30.2 km;

relay indications: z2/z3/CR. o TPCIL line-2 CB tripped in zone-2; fault distance = 32.59 km; relay

indications: z2/z3 (according to FIR of TPCL, at NPS end the fault was sensed through TPCIL remote end CBs of line-2, bus coupler and line-1).

2. From EL outputs, vast time difference (of about 1.5 minutes) was noticed between carrier

sent and carrier receive signal timings: TPCL end (line-1): carrier sent at 7:02:52.630 hrs NPS end (401_P444_21M1): carrier received at: 7:04:32.26 hrs

PGCIL: High pollution level could be reason for causing the fault. Efforts such as deployment of polymer insulator, fine tuning relay settings were carried

out. Recommendations:

a. At NPS end, corrective measures shall be taken to avoid tripping of line-2 CB for the fault on line-1 and vice versa.

b. Both NPS and TPCL shall ensure time synchronization with each other. c. Status of recommendations of PSAG-1 meeting held at NPS (on 24th July, 2013 ) shall be

submitted.

12 Tripping of 400/220 kV

ICT-1 AT TALAGUPPA 9-10-2014 at 4:58 hrs

As per FIR ICT tripped due to operation of back up protection

GI-1

Deliberation: KPTCL:

At Talaguppa, ICT-1 tripped on operation of R phase back up OCR (400 kV side).

The tripping was due to suspected mal operation of the R phase OCR (400 kV side).

Corrective action: back up OCRs and EFR of ICT-1 were tested and RAPDK static type OCR of R phase was replaced by spare relay existing in the station.

13 Tripping of 400kV

Raichur-Munirabad line 9-10-2014 at 14:03 hrs

line tripped due to operation of carrier lock out relay

GI-1

Deliberation:

It is noted that carrier lock out is due to inadequate battery power for the PLCC systems.

ANNEXURE - II

14

KPCL: Battery system procurement is under way. Recommendations:

KPCL is requested to expedite the process of installing adequate DC batteries for PLCC system.

II. AUTO-RECLOSE (A/R) FAILURE/ NON-OPERATION DURING

TRANSIENT FAULT The following tripping incidents, due to non-operation of Auto-Reclose function, were discussed in the 37th Meeting of PCSC.

S.No Element Date &

Time Reason PCSC Deliberations

1 400kV VTPS-Malkaram-1

18-09-2014 at 16:54

Line tripped on R-phase to earth fault. Line did not auto reclose

-

2 Tripping of 400kV Thrissur-Kochi line-1 & 2

28-09-2014 at 2:44hrs

Line tripped on R-phase to earth fault. Line did not auto reclose

Thrissur end: It was 3-phase trip. PLCC is healthy. Carrier received. Line-2 is on weak

load. Issue has been

referred to OEM (M/s Siemens).

Kochi end: Main-2 relay is not

sensing. Main-1 relay is with

DR. Main-2 relay is with

V & I signals. If relay operates only triggering would be there.

3 400kV Mettur-Arasur

line-1 29-09-2014 at 21:10 hrs

line tripped due to Y-Phase to earth fault. Line

A/R is not in service.

Rajan

(14/16)

ANNEXURE - II

15

did not auto reclose as Auto reclose scheme is kept in non-auto mode.

4 400 kV MADURAI - NTPL 04-10-2014 at 13:41

R-phase to earth fault. Line did not auto reclose at NTPL end

Now A/R is working.

The day prior to the PCSC meeting day, it operated correctly.

5 400 kV NEYVELI TS 2

(EXP) - PUGALUR 05-10-2014 at 21:47hrs

Y-phase to earth fault had occurred in line. Line did not auto reclose. DT was received from Neyveli TS2(EXP) end

Have to submit remedial measures

6 400 kV NELLORE - CHITTUR

06-10-2014 at 15:39 hrs

B-phase to earth fault. Line did not auto reclose at Nellore end.

After testing it was not in A/R mode.

Now it has been put into A/R mode.

7 400 kV HASSAN - UPCL

2 07-10-2014 at 16:09 hrs

Y-phase to earth fault. Line did not reclose at Hassan end due to DT receive from UPCL end. As per UPCL FIR Suspected PLCC mal-operation had caused DT send.

Now rectified.

III. OVER VOLTAGE TRIPPING

The following over voltage tripping incidents were discussed in the 37th Meeting of PCSC .

S. No. Element Date & Time

Reason / PCSC Deliberations

1 400kV VTPS-Satenapalli-2

19-09-2014 at 02:08 As reported line tripped on operation of over voltage.

FIR, D.R/ E.L of VTPS end not submitted

2 400kV Srisailam-Satenapalli-2

19-09-2014 at 20:53 hrs

As reported line tripped on operation of over voltage.

D.R of Srisailam end not submitted

Rajan

(15/16)

ANNEXURE - II

16

-

3 400 kV Chitoor - Thiruvalam & 400 kV Chitoor - Sriperumbudur

October, 2014 PGCIL: Positive error at Thiruvalam has been corrected. If same phase is causing tripping on different

occasions, then it could be a CVT problem. SRLDC: APTRANSCO has to check up grading of the

line (in voltage and time) and ensure DO/PU ratio is above 98%.

APTRANSCO: Everyday O/V tripping is there at night. M1 and M2 relays have sensed the O/V. As two phases (Y & B) are showing O/V, it

could not be a CVT problem. Recommendations: a. APTRANSCO is requested to check the drop

off to pick up ratio of over voltage relay and CVTs at Chitoor.

b. APTRANSCO is also requested to check the over voltage grading of all other 400 kV lines at Chitoor substation.

*****

Rajan

(16/16)

Islanding Scheme Implemented in Southern Region as On 01-10-2014

Islanding Scheme-Southern Region SRPC,Secretariat

Rajan

ANNEXURE III (1/18)

Islanding Scheme-Southern Region

As on October 2014 Page 1

Contents 1. Basic Islanding Philosophy ............................................................................................................... 2

a) Feeder Tripping Frequency: 47.9 Hz ............................................................................................. 2

b) What is islanding? ........................................................................................................................ 2

c) Guidelines used for identifying Islands in Southern Region ........................................................... 3

2. Hyderabad Islanding Scheme ........................................................................................................... 4

d) Anticipated Load Generation: 2500 MW ...................................................................................... 4

e) Generators Participating .............................................................................................................. 4

f) Load Participating ........................................................................................................................ 4

g) Feeders Tripping .......................................................................................................................... 6

h) Schematic Diagram ...................................................................................................................... 7

3. Chennai Islanding Scheme ............................................................................................................... 9

i) Anticipated Load Generation: 3000 MW ...................................................................................... 9

j) Generators Participating .............................................................................................................. 9

k) Load Participating ........................................................................................................................ 9

l) Feeders Tripping ........................................................................................................................ 10

m) Schematic Diagram ................................................................................................................ 11

4. Neyveli Islanding Scheme ............................................................................................................... 12

n) Anticipated Load Generation: 3600 MW .................................................................................... 12

o) Generators Participating ............................................................................................................ 12

p) Load Participating ...................................................................................................................... 12

q) Feeders Tripping ........................................................................................................................ 13

r) Schematic Diagram .................................................................................................................... 14

5. Koodankulam Islanding Scheme ..................................................................................................... 15

s) Anticipated Load Generation: 2100 MW .................................................................................... 15

t) Generators Participating ............................................................................................................ 15

u) Load Participating ...................................................................................................................... 15

v) Feeders Tripping ........................................................................................................................ 16

w) Schematic Diagram ................................................................................................................ 17

Rajan

ANNEXURE III (2/18)



1. Basic Islanding Philosophy

a) Feeder Tripping Frequency: 47.9 Hz

b) What is islanding? As the frequency starts drooping beyond a stage where is can be a threat to the Grid Security Automatic Frequency based Load Shedding is carried out to arrest the frequency with in the permissible level. If even with obtaining entire Load Shedding frequency is not arrested to a stable desirable value then it becomes prudent to separate some load with generation so that small electrical Islands are formed with proper load generation balance to ensure that frequency remains within the stable region. Such formed electrical islands help to extend power to some important load centre and helps in faster restoration of the system which has collapsed.

Islanding is a defense mechanism of splitting the larger power system in distress into smaller systems with relatively balanced load / generation in each of the split systems when power system may occasionally land in a situation of acute load / generation unbalance when its frequency nose dives. This may happen in un-intended system splitting or even by sudden loss of large source. Such events would be characterized by high rate of decline of frequency, compounded by the tripping out of generating units on under-frequency or on process protection when the frequency falls to such low values when auxiliary services fail to meet the plant process requirements. The usual and desirable defense mechanism against such a situation is obviously to resort to emergency load disconnection by appropriate under-frequency and/or rate of frequency decline (df/dt) relays but with even with this if frequency does not get arrested then it is prudent in splitting the larger power system in distress into smaller systems with relatively balanced load / generation in each of the split systems. This action should be able to arrest the frequency decline to acceptable minimum failing which the system may spiral into a collapse. The negative about such an arrangement is that this will accelerate the collapse of the remaining part of the system and force-close any chance the larger system had to survive. If a generating station (or stations) is islanded with a group of proximate load bus bars, the same has to be triggered only below this frequency. Otherwise the islanding scheme will race with the load disconnection scheme and prevent the possibility of survival parent system. In other words, islanding should happen only if the frequency decline continues even after the expected load disconnection has happened.

Due to the inertia of the islanded system, whose frequency has been declining at the indicated rate, the recovery of frequency would happen only after some more time when the frequency decline rate falls and eventually reverses. How quickly this reversal happens will also be dependent on the load/generation mismatch of the islanded system, which will also have an impact on the post islanding survival. The higher frequency at which the island if formed the better its chance of survival. If the df/dt reversal does not happen up to 47.0Hz, there is likelihood of the generating units tripping out and triggering a collapse of the newly formed island. Use of a df/dt triggering at a much higher threshold frequency could be useful in this regard.

Rajan

ANNEXURE III (3/18)



It is desirable to have Generation capacity significantly in excess of the load in the island. But such an option puts the demand of isolating a large generation capacity and comparatively less load in the island from the parent system.

Frequency stability of the island will be poor as it is a very small system with poor system governing and survival for any significant length of time will depend on enabling Governor Control.

Systems having Hydro, Diesel or Combustion Turbine Generators are better in this regard as its output change is direct and does not depend on indirect process of a steam unit.

While considering the islanding scheme, the high risk of failure / collapse of the island must be recognized and survival should only be viewed as a bonus. However, survival chance increases if the island can become significantly larger to include a few hydro and GT stations which are more amenable to control. In the long term significantly larger islands with fair load generation balance needs to be considered.

c) Guidelines used for identifying Islands in Southern Region

Approved Islanding Scheme in Southern Region is non-adaptive in nature; Islands are formed with anticipated Load Generation balance and with tripping of pre decided feeders.

Islanding should be of 1500 MW or above.

Islanding frequency shall be below minimum frequency at which Grid has sustained.

The islanded electrical system should have 20% more generation than Load.

Generators should be on FGMO/RGMO.

Islanding Area should not have long lines.

Load Flow study to be carried out for the islanded.

No UFR should be in the Islanding feeders.

Island should be formed by tripping minimum lines.

Preferably Islanding scheme should have Good Hydro-Thermal – Gas Mix.

Wind generating Feeders shall not form part of Islanding Scheme hence incoming wind feeder to the substation to be tripped at Islanding Frequency.

All Generation shall go to House Load if Island fails especially Nuclear Stations.

High Frequency time graded tripping of generators if frequency rises above 52 Hz even after FGMO/RGMO operation on non-availability of anticipated loads at the time of separation.



2. Hyderabad Islanding Scheme

d) Anticipated Load Generation: 2500 MW

e) Generators Participating S/No Generator Entity Anticipated MW Supplying 1 Ramagundam NTPC Stage I : 3X200 MW

Stage II : 3X500 MW Stage III : 1X500 MW= 2600 MW

2 KTPP Bopalapally TSGENCO 1X500 MW =500 MW

f) Load Participating Load Entity MW Remarks

220KV Bellampally feeder TSTRANSCO 40

132KV Kesoram Cements feeder TSTRANSCO 2

132 kV Railways feeder-1 TSTRANSCO 0

132KV Railways feeder-2 TSTRANSCO 6

132KV Manchiryal feeder TSTRANSCO 34

132KV Yellampally feeder TSTRANSCO 33

132KV Durshed feeder-2 TSTRANSCO 28

132KV Durshed feeder-3 TSTRANSCO 28

132KV Sultanabad feeder TSTRANSCO 30

220KV Siddipet feeder-1 TSTRANSCO 36 Included in AUFR scheme in stage-4

220KV Siddipet feeder-2 TSTRANSCO 36

220/132KV 100MVA ICT-1 TSTRANSCO 38



220KV Sadasivapet feeder-1 TSTRANSCO 29

220KV Sadasivapet feeder-2 TSTRANSCO 29

132kV Medchal feeder-1 TSTRANSCO 0

Idle charged/ stand by source

132kV Medchal feeder-2 TSTRANSCO 0 132kV Bhungir feeder TSTRANSCO 0 132kV Moulali feeder TSTRANSCO 0

132 kV Gunrock feeder TSTRANSCO 0 132kV SRT feeder TSTRANSCO 0

132 kV HMT & IDPL feeder TSTRANSCO 0

132KV Bolaram feeder TSTRANSCO 94

132 kV RCPuram feeder TSTRANSCO 0 Idle charged/ stand

by source



132/33KV 80MVA PTR-4 TSTRANSCO 61













132KV Imlibun feeder TSTRANSCO 44

132KV Bandlaguda feeder TSTRANSCO 43

132 kV Shivarampally TSTRANSCO 0 Idle charged/ stand

by source 132KV Jublee Hills feeder-1 TSTRANSCO 63

132KV Jublee Hills feeder-2 TSTRANSCO 63

132 kV Shamshabad feeder TSTRANSCO 0 Idle charged/ stand

by source 132KV Midhani feeder TSTRANSCO 6

132KV RCI feeder TSTRANSCO 5









220KV Gunrock feeder-1 TSTRANSCO 60

220KV Gunrock feeder-2 TSTRANSCO 61

220KV Moulali feeder-1 TSTRANSCO 115

220KV Moulali feeder-2 TSTRANSCO 114








Total Load 2634

Loads Under AUFR Scheme 200

Net Load 2434

g) Feeders Tripping S.No Voltage Level From Bus Entity To Bus Entity 1 400 D/C Bhadrawati PGCIL Ramgundam NTPC 2 400 S/C Dichipally TSTRANSCO Ramgundam NTPC 3 400 S/C Warangal PGCIL Khammam PGCIL 4 400 D/C Ramgundam NTPC Nagarjunasagar PGCIL 5 400 D/C Malkaram TSTRANSCO VTPS-IV APTRANSCO 6 400 D/C Mamidappaly TSTRANSCO Srisailam TSTRANSCO 7 400 D/C Mamidappaly TSTRANSCO Khammam PGCIL 8 400 S/C Ghanapur PGCIL Kurnool PGCIL 9 400 S/C Ghanapur PGCIL Nagarjunasagar PGCIL 10 220 S/C Mamidappaly TSTRANSCO Shadnr TSTRANSCO 11 220 S/C Mamidappaly TSTRANSCO Shamshabad TSTRANSCO 12 220 D/C Chandrayangutta TSTRANSCO Dindi TSTRANSCO 13 220 D/C Gajwel TSTRANSCO Minpur TSTRANSCO 14 220 S/C Gajwel TSTRANSCO Kamareddy TSTRANSCO 15 220 S/C Shankrapally TSTRANSCO Tandur TSTRANSCO 16 220 S/C Shankrapally TSTRANSCO Shadnr TSTRANSCO 17 220 S/C Shankrapally TSTRANSCO Yeduramarayil TSTRANSCO 18 220 S/C Malkaram TSTRANSCO Bhongir TSTRANSCO 19 220 S/C Malkaram TSTRANSCO NRKPY TSTRANSCO 20 220 S/C Shapoornagar TSTRANSCO KTPS TSGENCO 21 220 S/C RSS TSTRANSCO MDRM TSTRANSCO 22 220 S/C RSS TSTRANSCO BMG TSTRANSCO 23 220 S/C RSS TSTRANSCO VMNR TSTRANSCO 24 220 S/C RSS TSTRANSCO JGT TSTRANSCO 25 220 D/C Durshed TSTRANSCO Siddepet TSTRANSCO 26 220 D/C RSS TSTRANSCO NAGARAM TSTRANSCO 27 220 D/C Warangal TSTRANSCO NAGARAM TSTRANSCO 28 132 S/C Shapoornagar TSTRANSCO Naraspur TSTRANSCO 29 132 S/C Shapoornagar TSTRANSCO Gumadidala TSTRANSCO 30 132 S/C Chandrayangutta TSTRANSCO Turkayamjal TSTRANSCO 31 132 D/C Malayalapally TSTRANSCO RTS-B TSTRANSCO 32 132 S/C Malayalapally TSTRANSCO JGT TSTRANSCO 33 132 S/C Malayalapally TSTRANSCO Pochampad TSTRANSCO 34 132 S/C Malyalapally TSTRANSCO OCM TSTRANSCO



35 132 S/C Malayalapally TSTRANSCO Chityal TSTRANSCO 36 132 S/C Malayalapally TSTRANSCO Dhamaram TSTRANSCO

h) Schematic Diagram

B

W

R

D

G

H

M

N

V

M

K

S

B

K

K

M

S S

G

M K

C

D

S

T Y

N

B

M

K

S

B

J

V

M B

S

D

N



3. Chennai Islanding Scheme

i) Anticipated Load Generation: 3000 MW

j) Generators Participating S/No Generator Entity Anticipated MW

Supplying 1 Ennore TPS TANGEDCO 100 2 North Chennai TPS Stage-1 TANGEDCO 630 3 NTECL Vallur NTECL 1500 4 GMR GMR 80 5 MAPS NPCIL 440 6 North Chennai TPS Stage-2 TANGEDCO 1000

k) Load Participating LOAD ENTITY MW ETPS TANGEDCO 140MW

Tondiarpet 230kV SS TANGEDCO 170 MW Manali 230kV SS TANGEDCO 100 MW

Alamathy 400kV SS TANGEDCO 80 MW Korattur 230kV SS TANGEDCO 140 MW

Basin Bridge 230kV SS TANGEDCO 120 MW Mylapore 230kV SS TANGEDCO 100 MW

Gummidipoondi 230kV SS TANGEDCO 200 MW Sriperumpudur 400kV SS TANGEDCO 300 MW

Kilpauk 230kV SS TANGEDCO 100 MW Koyembedu 230kV SS TANGEDCO 225 MW Tharamani 230kV SS TANGEDCO 300 MW

SPKoil 230kV SS TANGEDCO 170 MW Kadaperi 230kV SS TANGEDCO 150 MW Siruseri230kV SS TANGEDCO 100 MW KITS 230kV SS TANGEDCO 90 MW

Veerapuram230kV SS TANGEDCO 75 MW Oragadam230kV SS TANGEDCO 100 MW

Nokia 230kV SS TANGEDCO 20 MW SIPCOT TANGEDCO 50 MW Hyundai TANGEDCO 20 MW

Acharapakkam 230kV SS TANGEDCO 130 MW Hosur 230kV SS TANGEDCO 200 MW

Arani TANGEDCO 150 MW



Mosur TANGEDCO 230 MW Thiruvalam TANGEDCO 180 MW

Total TANGEDCO 3640 MW UF relief TANGEDCO 620 MW

Effective load TANGEDCO 3020 MW

l) Feeders Tripping S.No Voltage Level From Bus Entity To Bus Entity 1 400 S/C ALMATHY TANTRANSCO NELLORE PGCIL 2 400 S/C SRIPEUMBADUR PGCIL NELLORE PGCIL 3 400 S/C SRIPEUMBADUR PGCIL KOLAR PGCIL 4 400 S/C SRIPEUMBADUR PGCIL CHITTOR PGCIL 5 400 D/C KALIVENDAPETTU PGCIL PUGULLUR PGCIL 6 400 D/C CHITTOR PGCIL THIRUVALAM PGCIL 7 400 S/C SV CHATRAM TANTRANSCO PONDICHERRY PGCIL 8 230 S/C SINGAREPET TANTRANSCO THIRUVALAM TANTRANSCO 9 230 S/C SINGAREPET TANTRANSCO ARNI TANTRANSCO 10 230 S/C VILIPURAM TANTRANSCO ACHARAPAKKAM TANTRANSCO



m) Schematic Diagram



4. Neyveli Islanding Scheme

n) Anticipated Load Generation: 3600 MW

o) Generators Participating S/No Generator Entity Anticipated MW

Supplying 1 Neyveli TS1 NLC 475 MW 2 Neyveli TS2 NLC 1470 MW 3 Neyveli TS1 Expn NLC 400 MW 4 STCMS STCMS 250 MW 5 MTPS TANGEDCO 1070 MW 6 Hydro TANGEDCO 500 MW 7 GTS TANGEDCO 500 MW 8 SPCL TANGEDCO 100 MW

p) Load Participating LOAD ENTITY MW

Thudialur TANGEDCO 280 O.K Mandapam TANGEDCO 200 Palladam TANGEDCO 200 Udumalpet TANGEDCO 300 Anaikadavu TANGEDCO 10 Pykara TANGEDCO 10 Arasur TANGEDCO 300 Ingur TANGEDCO 300 Gobi TANGEDCO 300 Salem TANGEDCO 280 Mettur TANGEDCO 100 Deviakurichi TANGEDCO 200 KR’Thoppur TANGEDCO 350 Unjanai TANGEDCO 140 Alundur TANGEDCO 130 Trichy TANGEDCO 210 Thiruvarur TANGEDCO 210 Kadalangudi TANGEDCO 80 Samayapuram TANGEDCO 70 Eachangadu TANGEDCO 40



Perambalur TANGEDCO 185 Thanjavur TANGEDCO 130 Singarapet TANGEDCO 150 Arani TANGEDCO 150 TVMalai TANGEDCO 128 Vinnamangalam TANGEDCO 60 Kariamangalam TANGEDCO 200 Villupuram TANGEDCO 146 Cuddalore TANGEDCO 120 Thiruvalam TANGEDCO 180 Mosur TANGEDCO 228 Pondy TANGEDCO 170 Palakkad TANGEDCO 250 Total 5807 UF Relief 2000 Sustained load 3800

q) Feeders Tripping S.No Voltage Level From Bus Entity To Bus Entity

1 400 D/C Hosur PGCIL Salem PGCIL 2 400 D/C Palakkad PGCIL Trichur PGCIL 3 220 D/C Palakkad KSEB Trichur KSEB 4 400 D/C Myvadi PGCIL Abisekapatty PGCIL 5 400 S/C Myvadi PGCIL Chekkanoorani PGCIL 6 400 S/C Alundur PGCIL Chekkanoorani PGCIL 7 400 S/C Alundur PGCIL Karaikudi PGCIL 8 400 S/C Neyveli NLC Pugalur PGCIL 9 400 S/C Neyveli Expn NLC Pugalur PGCIL

10 230 S/C Alundur TANTRANSCO Alagarkoil TANTRANSCO 11 230 S/C Pudukottai TANTRANSCO Alundur TANTRANSCO 12 230 S/C Alundur TANTRANSCO Pugalur TANTRANSCO 13 230 S/C Thiruvarur TANTRANSCO Karambium TANTRANSCO 14 230 S/C Pugalur TANTRANSCO Myvadi TANTRANSCO 15 230 S/C Pudansandai TANTRANSCO Unjanai TANTRANSCO 16 230 S/C Pudansandai TANTRANSCO Deviakurichi TANTRANSCO 17 230 S/C Udumalpet TANTRANSCO Idukki TANTRANSCO 18 230 S/C Udumalpet TANTRANSCO Sembatti TANTRANSCO 19 230 S/C Metur Auto TANTRANSCO Karimangalam TANTRANSCO 20 230 S/C Metur Auto TANTRANSCO Hosur TANTRANSCO 21 230 S/C Singarpet TANTRANSCO TV Malai TANTRANSCO



22 230 S/C Singarpet TANTRANSCO MTPS TANTRANSCO 23 230 S/C Singarpet TANTRANSCO Salem TANTRANSCO

r) Schematic Diagram



5. Koodankulam Islanding Scheme

s) Anticipated Load Generation: 2100 MW

t) Generators Participating

S/No Generator Entity Anticipated MW Supplying

1 TTPS TANGEDCO 1050 2 Koodankulam NPCIL 1000 3 Hydro TANGEDCO 200 4 GTS TANGEDCO 160 5 IPP&CPP TANGEDCO 800 6 RGCCP NTPC 270 7 Sabarigiri KSEB 150 Total 3630

u) Load Participating LOAD ENTITY MW

Kayathar TANGEDCO 200 Anupankumam TANGEDCO 160

Kodikurichi TANGEDCO 90 S.R.Pudur TANGEDCO 160 Sanganeri TANGEDCO 45

Udhayathur TANGEDCO 10 TTN Auto ss TANGEDCO 90 Melavittan TANGEDCO 150 Pasumalai TANGEDCO 142

Theni TANGEDCO 150 Sembatty TANGEDCO 110

Pudhansandai TANGEDCO 240 Pugalur TANGEDCO 130

KaraiKudi TANGEDCO 105 Azhagarkovil TANGEDCO 180

Kavanoor TANGEDCO 88 Karambium TANGEDCO 60 Pudukottai TANGEDCO 160

R,Nathapuram TANGEDCO 128 Amuthapuram TANGEDCO 10

Veeranam TANGEDCO 10

Rajan

ANNEXURE III (16/18)



Pothenkode KSEB 254 Edamon KSEB 44 Kudhara KSEB 103 Edapon KSEB 89

Sabarigiri KSEB 17 Palom KSEB 168

UF Relief 800 Sustained load 2160

v) Feeders Tripping S.No Voltage Level From Bus Entity To Bus Entity

1 220S/C Idukki KSEB Palom KSEB 2 220S/C Ambalmukam KSEB Sabirigiri KSEB 3 220S/C Ambalmukam KSEB New Palom KSEB

Rajan




w) Schematic Diagram

Rajan


ANNEXURE IV

Proposed Modifications in logic of Nagjhari SPS (KPTCL)

Slno Conditions as per the present logics Modification suggested 1 With all the lines in service and any one of

the line flow is >590A for a duration of 1

sec will lead to tripping of Generating Unit

3 OR Unit 6 @ Nagjhari directly.

No change required

2 In case of outage of any one line and flow

on any one of the other lines in service is

>590A forduration of 1 sec and the total

generation is >900MW will lead to

tripping of Generating unit 3 0r Unit 6 @

Nagjhari.

The condition that the

generation should be

>900MW is not required

since overloading of any

line is independent of MW

availability at Nagjhari

bus.

3 In case of tripping of 220KV Sirsi 1&2

lines at Hubli OR tripping of 220KV

Harthi 1&2 lines at Bidnal and the

generation is >900MW will lead to

tripping of Generating unit 3 0r Unit 6 @

Nagjhari.

1. Tripping of Saudatti line

at Bidnal end may be

added to Harthi 1&2

lines with an additional

AND gate.

2. The total MW available

at Nagajhari bus may be

revised to 700MW from

900MW.

Rajan

(1/1)

Rajan

ANNEXURE V (1/72)

1

Record Notes of discussions (of PSAG-10) held at Kadra, Kodasalli (KPCL) Power House, Switch Yard on 12.11.2014 & Kaiga Power House

on 13.11.14 to discuss the Grid Disturbances that occurred in Kadra, Kodasalli during the months of September-October 2014

The Protection System Analysis Group (PASG-10) meeting was held on 12th November at Kadra, Kodasalli Power Houses. Shri N.P.Gajakosh , Superintending Engineer (E),In charge Kadra/Kodasalli Power House welcomed the members and participants . The List of Participants is enclosed herewith as Annexure I. KPCL personnel briefed the Group regarding the Grid disturbances that occurred during the 26th September 2014,5th and 14th October 2014.

The Protection System Analysis Group (PASG-10) meeting was held on 13th November at Kaiga (NPCIL) Nuclear Power Plant. Shri M.P.Hansara , Site Director, Kaiga Power House and Shri M.Srinivas , Chief Superintendent, Kaiga Power House welcomed the PSAG members and participants. NPCIL, Kaiga personnel briefed the members about the Kaiga, Nuclear Power plant and its performance highlights (through power point presentation). Kaiga, NPCIL also briefed the members about the Grid Disturbances that occurred in Kadra-Kodasalli Power houses during the months of September –October 2014.The List of Participants is enclosed herewith as Annexure II.

The details as submitted by KPCL to PSAG query regarding the 26th September 2014, 5th and 14th October 2014 Grid Disturbances is enclosed herewith as Annexure III & IV (respectively for Kadra & Kodasalli Stations) . The detail as submitted by Kaiga, NPCIL is enclosed herewith as Annexure V.

The PSAG-10 members reviewed the status of implementation of Protection Audit (conducted during November – December, 2012 ) recommendation and status of implementation of the previous Sub Group /Special meeting of PCSC conducted in the Kali –Complex Power Stations. The status of implementation as submitted by KPCL substations is enclosed herewith as Annexure VI. The status of implementation as submitted by Kaiga, NPCIL is enclosed herewith as Annexure VII (w.r.t. Protection Audit and PSAG-8).

Rajan

ANNEXURE V (2/72)

2

I. Discussion and deliberations of the Group:

a. Tripping at 26-09-2014 at 15:50 hrs 1. It was informed by KPCL representative that that B-phase to earth fault had occurred

in 220kV Kadra-Kodasalli line. Main-2 distance relay (PZ1000) had sensed the fault in zone-2, but backup e/f relay operated at Kodsalli end. The fault in B-phase was initially a high resistance fault as the voltage dip was very less and fault current was around 1.2kA. The fault current was observed to be gradually increasing. This was verified with the relay event log. The issue of trip command from Mian-1 relay could not be confirmed from the relay event log. Main-1 relay (Quadramho) is faulty at Kodasalli end.

2. At Kadra end it was told that the Main-2 relay (PZ1000) had sensed the fault in zone-1. However it was observed from the relay event log that the gradually increasing fault current was persisting for around 380 ms. Time at which distance relay picked up and issued trip could not be verified as D.R was not available.

3. 220kV Kaiga-Kadra line and 220kV Kaiga-Kodasalli line tripped from Kaiga end at 328ms and 400 ms respectively.

4. The 220kV Nagjheri-Kodasalli lines were kept in open condition from Nagjheri end. 5. The running unit at Kodasalli tripped due to tripping of evacuating lines. Hence bus

dead condition occurred at Kodasalli and Kadra. 6. The Prefault and Post fault conditions were depicted as below.

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ANNEXURE V (3/72)

3

b. Tripping at 05-10-2014 at 17:22 hrs

1. B-phase to earth fault had occurred in 220kV Kadra-Kodasalli line. This was a gradually developing high resistance fault. Zone-2 had picked up at Kadra and Kodasalli but did not trip. 220kV Kaiga-Kadra and 220kV Kaiga-Kodasalli lines tripped from Kaiga end on distance protection zone-2 in 300ms and 400ms respectively.

2. The 220kV Nagjheri-Kodasalli lines were kept in open condition from Nagjheri end. 3. The running unit at Kodasalli tripped due to tripping of evacuating lines. Hence bus

dead condition occurred at Kodasalli and Kadra. 4. The Prefault and Post fault conditions were depicted as below.

4

c.Tripping at 14-10-2014 at 15:18 hrs 1. As informed by KPCL representative that distance protection zone-2, B-phase had

operated at Kodasalli end. Fault was cleared from Kadra end. The time of zone-2 pickup and trip could not be verified due to the absence of D.R. Back up earth fault operated at Kadra end.

2. Two units were in operation at Kodasalli. 3. 220kV Kaiga-Kodasalli tripped from Kaiga end on operation of distance protection

Zone-3, B-phase at Kaiga. Fault was observed to be persistent for 560 milli seconds. 4. The running Unit at 220kV Kodasalli power house tripped as 220kV lines connected

from Kodasalli to Kadra and Kaiga tripped and 220kV Nagjheri line-1&2 were kept out of service. This resulted in de-energization of 220kV bus at Kodasalli power house. Generation loss was 74 MW.

5. The Prefault and Post fault conditions were depicted as below.

5

II. Recommendations of PSAG-10 & Follow up for Kadra and Kodasalli Generating Stations (KPCL).

S.NO Recommendation To be implemented by

Implementation

Schedule 1 The PSAG-10 members recommended to replace the

Main I (Q21 static Quadramho relay -SHPM 101) distance protection relays with Numerical relays having DR and EL features.

KPCL in coordination with KPTCL

Latest by December, 2014.

2 The PSAG group also advised KPCL to test the Main II Relay (PZ1000 numerical relay) at the earliest .


Latest by December, 2014.

3 The PSAG group recommended to have a uniform Zone II time settings as agreed in the Tripartite meeting of KPCL, KPTCL and Kaiga (NPCIL) held during 11th& 12th of December, 2013) in the Kaiga –Kali Complex. KPCL informed that they had revised their Zone II time settings from 350 ms to 300 ms in all the lines connected to Kadra, Kodasalli and Kaiga Power House.


Completed on 12.11.2014.

4 The Resistive reach of distance protection relay of Kadra – Kodasalli (both ends), Kadra – Karwar I, Kadra – Karwar II (Kadra end), Kodasalli – Nagjheri I, Kodasalli – Nagjheri II (both ends) lines to be increased so as to operate on high resistance faults within the permissible limits . Since the present settings are prone to under reach and initiating unwanted tripping at the other locations, PSAG has recommended to suitably increase the resistive reach of all the lines. PSAG advised KPCL to revise the settings at the earliest.


Latest by 21.11.2014

5 PSAG recommended to make the carrier aided protection functional for 220kV Kadra-Kodasalli, 220kV Kadra-Kaiga and 220kV Kodasalli-Kaiga lines. In addition, since most of the faults are seen as high resistance fault, PSAG suggested to revise the existing PUR to POR scheme for all the lines at Kali complex.


Latest by December, 2014

6 The PSAG group noted that most of the faults were in the ‘B’ Phase (of RYB) to ground faults. The group observed that it may be due to thick vegetation below Kadra – Kodasalli, Kadra – Kaiga, Kodasalli - Kaiga line. Hence the PSAG group members advised to have regular thorough line patrolling and clearing the corridor (i.e. Right Of Way).

By KPTCL Regularly / As and when needed.

6

7 PSAG had recommended to have a uniform setting for the backup earth fault protection (67N) provided through distance relay (i.e PZ1000) and separate back up earth fault relay (CDD21 of English Electric, electro mechanical) immediately.



8 The PSAG group advised to disable the phase over current protection in distance relays (i.e PZ1000 of CSPC make) immediately.



9 KPCL informed that installation of GPS for time synchronization of all relays and other protection devices is under process. KPCL is requested to expedite the same.

KPCL As reported earlier.

10 It is suggested to check timings (opening and closing) on Kadra line CB test at Kodasalli station periodically and the record of checking to be maintained in the substation.

KPCL Periodically

11 It was observed that Kodasalli – Nagjheri I & II lines were kept open at Nagjheri end on 26.09.2014, 5.10.2014 & 14.10.2014 during bus dead conditions at Kodasalli station. KPTCL (SLDC) is requested to clarify /review the issue.

KPTCL / SLDC Latest by 21.11.2014

12 The DR and EL data of the line/unit tripping shall be made available for analysis at station level / SLDC /SRLDC/SRPC level.

KPCL/KPTCL/NPCIL

As per the IEGC (i.e. within 24 Hours)

The action/steps taken by KPCL/KPTCL in implementing the recommendation / review of protection coordination settings as suggested by PSAG-10 to avoid the similar Grid Disturbance may please be reported to SRPC Secretariat on or before the 38th PCSC meeting (scheduled on 27.11.2014) through e-mail / fax latest by 25.11.2014.

X---------------------------X----------------------------X--------------------------X---------------------X

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ANNEXURE - I (1/2)

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ANNEXURE - I (2/2)

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ANNEXURE - II (1/2)

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ANNEXURE - II (2/2)

Rajan

ANNEXURE V (1/7)

GEC ALSTHOMMADRAS

admin

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ANNEXURE V (2/7)

��

1

2

4

6

7

8

9

10

11

12

13

14 Setting = 28.0 Sec

2/47T Timer(0.1-1.0SEC) VTT-11ZG8152B(M)

2/29

Setting = GT#1-0.250 Sec & GT#2-0.5 Sec

SETTI VTT-11ZG8157B(M)

*

Timer(0.1-1.0SEC) VTT-11ZG8152B(M)

AUX.RELAY.

AUX.RELAY.

AUX.RELAY.

Winding temp.high Alarm

Winding temp.high Trip

Oil temp.high Alarm

WTI Set 100 degree C trip

OTI Set 70 degree C Alarm

OTI Set 90 degree C Alarm

*

*

Setting = 0.1 A, SR=185 Ohms

PSM=0.4, TMS=0.6

Setting = 1.0 Sec

WTI Set 80 degree C alarm

30DG

30LG

Oil temp.high Trip

30BG/AG Bucholz relay Alarm & Trip.

AUX.RELAY.

Fire protection trip AUX.RELAY.

Pres. Relief valve operated. AUX.RELAY.

AUX.RELAY.

64GT

51NGT

G.T. H.V. REF

G.T. B/U E/F Protn.

30FG

30EG

30HG

2/51NGT

30GG

PSM=1.0, TMS=0.7, Inst = 8 Amps (800%)

2/50Z

GT Breaker L.B.B. Protn.

UNIT AUXILIARY TRANSFORMER#1&2 PROTECTION

CAG-14AF12A

CDG-11AF005SA5

Timer(0.1-1.0SEC)

Setting = 5% of 1 A (50 mAmps)

Setting = 250 mSec3

50Z

��

CTIG-39BF8012A(M)

VTT-11ZG8152B(M)

GENERATOR TRANSFORMER#1&2 PROTECTION as on 28-01-.2012

50/51GT-ABC Back-up O/C HV side CDG63EG8172Z

��

87GTABC.(O/H Diff.) Over all Differential Prot. MICOM-P633 Setting= Id=0.2 A,m1=0.2,m2=0.8,Ir=1.5.

��

admin

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ANNEXURE V (3/7)

Nuclear Power Corporation of India Limited

Kaiga Generating Station Electrical Maintenance Unit -1&2 Relay Testing Laboratory SETTING SHEET FOR 220KV SWYD. RALAYS As on 08/05/2014

1

1) Main protection Distance relay settings for lines (SHPM101)

Description Line-01 (#) Line-02 (#) Remarks Length of Line in KM 13 16

CT RATIO 800/1 A 800/1 A 1a) Distance Relay SHPM101 SHPM101

Relay character QUAD QUAD K1 1 1 (#) Red color fonts

indicates the setting changes done on Dated; 08/05/2014.

K2 0.4 0.4 K3 32 32 K4 0 0 K5 0.9 0.9 K6 0.08 0.08 K11 1 1 K12 0.2 0.4 K13 0.02 0.08

K14/24 1 1 K15 1 1 K21 3 3 K22 0.2 0.6 K31 4 5 K32 0.9 0.6 K33 1 1 K35 1 1 K36 0.2 0.5 K37 0.25 0.25 A/b N/A N/A

Z-2 TIME(m sec) 300 300

Z-3 TIME (m sec) 600 600 Tp ALL LEFT ALL LEFT Td ALL LEFT ALL LEFT

SW-1 RIGHT RIGHT SW-2 LEFT LEFT SW-3 RIGHT RIGHT SW-4 RIGHT RIGHT SW-5 RIGHT RIGHT SW-6 RIGHT RIGHT SW-7 LEFT LEFT SW-8 LEFT LEFT SW-9 RIGHT RIGHT Z-1 LEFT LEFT Z-2 LEFT LEFT Z-3 RIGHT RIGHT

ANGLE (Ph -Ph) 80 80 ANGLE (Ph -N) 80 80 TEST OPTION 01 01

LINE Zones Set Impedance In Ohms PRI / SEC

Set Impedance In Ohms PRI / SEC

Relay set distance in KM

Line-1 Line-2

Zone-01 4.27 / 1.708 5.18 / 2.072 10.47 (80.54%)

12.70 (79.38%)

Zone-02 11.2 / 4.48 12.6 / 5.04 27.45 ( 211.15%)

30.88 ( 193%)

Zone-03F 17.15 / 6.86 19.6 / 7.84 42.03 ( 323.31%)

48.04 ( 300.25%)

Zone-03R 0.8925/ 0.357 1.313 / 0.525 2.19 (16.85%)

3.22 (20.13%)

Rajan

ANNEXURE V (4/7)



2

2) Switch yard Line#1&2 and ICT#1&2 back up protection relays settings:

3) MICOM-P127_32 ICT#1 and 32 ICT#2 Relays: Under/Overpower protection(32ICT) for Tripping of

220kV Kaiga-Kadra(L1) and Kaiga-Kodasalli (L2) lines during non availability of One ICT and Overloading of other ICT in service as per FCN through 86B and through 32 ICTX aux. Relay and S/Y WAN as “ ICT-1/2 O/L” and SCADA alarm as “220kV L1/L2 Trip on ICT-1/2 O/L” provided ON dated: 31/11/2009.

Sl N

Micom P-127

I.C.T-1&2 Power

setting AT 0.9pF

Corresponding MVA

Action

ICT HV Current with pf

of 0.9 (% over load)

Actual relay setting

O/P of relay configured

Stage Setting Relay LED

1. 5MWe (Under power

5.55MVA

To sense non

availability of

one ICT

--

Stage-1.U/P PSM P>

6.4 MWe .

----

Alarm LED

Timer for stage-1 tp> 0sec

RL-2 reverse

p/u LED-5

2. 500MWe (Alarm)

555.55MVA

Over load

alarm

801.87 A (110%)

Stage-1.O/L PSM I>

≥ 0.91A (499.31Mw

e)

-----

Alarm LED

Timer for stage-1 t >

DMT 5.0sec. RL-4

LED-7

3. 550 MWe

(Over Power)

611.11MVA

Line 1&2 trip with a time

delay of 2 sec.

882 A (122%)

Stage-2.U/P PSM P>>

550.4 MWe

-----

Alarm LED

Timer for Stage-2 : tp>>

2.0Sec. RL-3 -----

NOTE: OUTPUT RELAY NO.2 WILL BE REMAIN IN DROPOUT CONDITION WHEN I.C.T POWER ≥6.4Mwe with LED.5 GLOWING CONDITION. RL-2 INVERSED TO P/U WHEN THE I.C.T POWER BELOW <6.4Mwe LOAD OR OTHER I.C.T TRIP CONDITION.

Relay Description LINE-01 LINE-02 ICT#1 ICT#2 Remarks CT RATIO Pri. / Sec. Pri. / Sec. Pri. / Sec. Pri. / Sec. 2a) Dir. Phase O/C. 67ABC (CDD41) 600/1 A 600/1 A 1600/1A 1600/1A PSM (IDMT) 900/1.5 900/1.5 1600/1A 1600/1A TMS 0.24 0.24 0.2 0.2 High set. Disabled Disabled 16000/10A 16000/10A 2b) Dir. E/F 67N (CDD41) 600/1 A 600/1 A 1600/1A 1600/1A PSM 180/0.3A 180/0.3A 320/0.2 A 320/0.2 A TMS 0.24 0.24 0.46 0.46 High set Disabled Disabled 12800/8A 12800/8A 2c) LBB Protection. 50Z (CTIG39) 600/1 A 600/1 A 1600/1 A 1600/1 A PSM 120/0.2A 120/0.2A 320/0.2A 320/0.2A Potential meter knob 1 1 1 1

2/50Z (External timer set value) 0.25 sec 0.25 sec 0.2 sec 0.2 sec 2d) Pole discrepancy timer. 2/47T 0.1 sec 0.1 sec 0.2 sec 0.2 sec 2e) Isolator parallel timer.29 25 sec 25 sec 25 sec 25 sec

Rajan

ANNEXURE V (5/7)



3

4) Swyd. Bus coupler protection relays setting:

5) 67L1/ 67L2 (MICOM-P127) Relays are provided for forward dir. Phase O/C & E/F protection to

trip L-1, 2 through 86B, 86Bx and through 67XA aux. relay SWYD.C/R WAN provided & addition to this, provided a Equation-A logic circuit (B/C with under current <150A) alarm in Swyd. C/R WAN for Lines-1&2 relays. Description 67L1 67L2 Operation Out put MICOM- P127 Set Values Pri. / Sec. Pri. / Sec. CT Ratio 600 / 1 A 600 / 1 A 4a) Dir. Phase O/C protection. 67ABC Pri. / Sec. Pri. / Sec. Stage-1.O/C (IDMT) I> PSM 800 / 1.33A 800 / 1.33 A TMS (IEC-SI Curve) 0.25 0.25 O/P-Led-5 & RL-2 Stage-2 O/C (Inst.) I >> PSM Disabled Disabled Timer for stage -2 tI>> Disabled Disabled O/P-Led-5 & RL-3 Stage-3 O/C (Inst.) I>>> PSM 3000 / 5A 3000 / 5A Timer for stage -3 tI>>> 0.2 sec. 0.2 sec. O/P-Led-5 & RL-4 4b) Dir. Phase O/C E/F protection. 67N Pri. / Sec. Pri. / Sec. Stage-1. E/F O/C (IDMT) Ie > PSM 160 / 0.27A 160 / 0.27A TMS (IEC-SI Curve) 0.25 0.25 O/P-Led-6 & RL-5 Stage-2 E/F O/C (Inst.) Ie >> PSM 2400 / 4A 2400 / 4A Timer for s tage-2 tIe >> 0.2 sec. 0.2 sec. O/P-Led-6 & RL-6 Stage-3 E/F O/C (Inst.) Ie >>> PSM Disabled Disabled Timer for stage -3 tIe >>> Disabled Disabled O/P-Led-6 & RL-7 4c) Broken conductor prtn. With Undercurrent [(B/C+ tBC) & (I< + tI<)] Through AND LOGIC Equation-A.

30% 30% Logic Equation ‘A’ to

P/U RL-1 to give Window alarm in swyd C/R .No trip

wired in this protection.

Broken conductor protection timer (tBC) 3.0 Sec. 3.0 Sec.

Under current protection (I<) 150/0.25A 150/0.25A Under current protectio n time delay (tI<) 0.0 Sec. 0.0 Sec.

Description Relay Setting Remarks

3a) LBB Protection.50Z 800/1A PSM 0.2A KNOB 1.0 Timer for 2/50Z 0.25 Sec. 3b) LBB Protection.50ZB 800/1A PSM 0.2A KNOB 1.0 Timer for 2/50Z 0.25 Sec. 3c) Over voltage Protection.59B1 PT Ratio: 220KV/110V Over voltage in % 110 % of 110V(Vn)+ time

o sec.

External timer.2/59B1 0.5 Sec. 3d) Over voltage Protection.59B2 PT Ratio: 220KV/110V Over voltage in % 110 % of 110V(Vn)+ time

o sec.

External timer.2/59B2 0.5 Sec. 3e) Pole discrepancy timer. 2/47T 0.1 sec. 3f) Synch. Check relay 25 PT Ratio: 220KV/110V Set under voltage block 85% 0F 110V Time delay for operation 3.0 sec.

Rajan

ANNEXURE V (6/7)



4

B/C+U/C EQUATION-A TIME DELAY TO OPERATE. 0.0 Sec. 0.0 Sec

B/C+U/C EQUATION-A TIME DELAY TO RESET. 0.0 Sec 0.0 Sec

6) MICOM-P127 Relay (67L1S / 67L2S) Reverse dir. Phase O/C Stage-2 & 3 protection (TOWARDS

SWYD.) and Equation-“A” logic circuit (Broken Conductor and stage-1 Ph. O/C >150A) to trip Line-1 or 2 through 86B, 86BX and through 67Bx relay line trip Swyd. C/R WAN. appears.

Description LINE-1 LINE-2 Remarks Protection relay (MICOM -P127) 67L1S 67L2S 5a) Dir. Phase O/C relay (67S -ABC) Pri. / Sec. Pri. / Sec. CTR Same as 67L1 &

67L2 Stage.1.O/C (Non dir. type) I> PSM 150 / 0.25A 150 / 0.25A Timer setting for stage -2 (tI>>) D.M.T. INST. INST. Stage.2 (Dir.) I>> PSM [Torque angle set at 225 °°°°]

800 / 1.33A

800 / 1.33A

O/P-Led-5 & RL-2

Timer setting for stage -2 (tI>>) 1.0SEC 1.0 sec. Stage.3 (Dir.) I>>> PSM [Torque angle set at 225 °°°°]

900/1.5A 900/1.5A O/P-Led-5 & RL-3

Timer setting for stage -3 (tI>>>) 0.2sec. 0.2sec. 5b) Broken conductor protection with non-directional over current.) [(B/C+ tBC & (I> + tI>)] through AND LOGIC Equation-A.

45% 45% Logic Equation ‘A’ to P/U RL-1 to give Window alarm in

swyd C/R & Trip wired through o/p relay No.RL-3

Broken conductor prtn timer (tBC) 4.0 Sec. 4.0 Sec.

Non Directional O/C stage -1 set (I>) 150/0.25A 150/0.25A B/C+O/C Equ. -A time delay to operate. 0.0 Sec. 0.0 Sec B/C+O/C Equation -A time delay to reset. 0.0 Sec 0.0 Sec

Remarks :(#) L-1 & 2 distance and back up protection relay settings revised on 08-05-2014 as per Technical unit approved copy dated: 06/05/2014 with revised settings details.(Annexure-1, 2 and 3)

Compiled by Checked by Reviewed by

Hanumantharayappa.K.R

Date: 08/05/2014

Ravikumar.S

Date: 08/05/2014

Jagadeesha

Date: 08/05/2014

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ANNEXURE V (7/7)

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ANNEXURE VI (1/18)

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ANNEXURE VI (2/18)

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ANNEXURE VI (3/18)

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ANNEXURE VI (4/18)

KPCL Phase I details Phase -I

Sl No. Name of Substation Details of workRemarks

Dead earth fault in 220V DC set 1 & 2 Already rectifiedRelays not synchronised with GPS Synchronising with all protection relays is

under progressA/R scheme for 220KV lines not available for lines Will be resolved at the earliest

2 220KV Gerusoppa Dam Power House

Different type of Numerical Distance protection is to beprovided as Main-II in place of Static Over current & earthfault protection.

Preparation of tender specification &Obtaining administrative approval is underprogress.

Carrier protection is out of service for Karwar 1 & 2 feeders Normalised & real time tests carried out

Main - 1 Distance Protection (SHPM101) is not in servicedue to power supply module problem for Karwar - 1 & 2feeders.

Procurement action is intiated shall be Completed On or before - 30.12.2014

Double Earthing of all supporting structures/elements is to Space problem was observed. However, it

1 220KV BTPS

220KV Kadra (Gen)3

1

Double Earthing of all supporting structures/elements is tobe ensured.

Space problem was observed. However, it will be solved.

Neutrals of Generating Transformers and LA's are to beexclusively earthed.

Space problem was observed. However, it will be solved.

4220KV Kodsalli S/S (Gen)

Carrier protection is not in service for all feeders (the realtime testing is pending)

Carrier Protection Real Time testing done.

5220KV Nagjhari power house

The LBB relay time & current are set at 1.5 sec & 0.2A forall feeders and generating transformers

Already done & LBB timing set at 0.4sec

220V DC earth fault persisting negative dead ground Will be rectified Old Electro-magnetic Relays to be replaced. Procurement action is intiated.LBB relay RAICA RXKL1 setting for ICT-II is kept at 50mA Will be re-setted at the earliest

The LBB relay timing is Observed to be 0.7 sec which is High. Can be reduced to 250 to 300 milli sec in co-ordination with pole discrepency relay of breaker.

Complied, all the lines & units LBB timing is set to 0.4 sec

Feeders with same Make & Type relay as Main -1 & Main -2 should be changed with differrent Make/Type relays for Main -1 & Main -2.

Carrier protection Is provided for all the feeders. SS-1 & SS-2 lines wave trap were not available during auit. The same has been normalized by KPTCL.

Feeders having O/C and E/F relays as Main -2 to bereplaced with distance relays for good protection co-

NIT issued & will be Complied on or before - 30.12.2014.

6 220KV RTPS

7220KV sharavathy SS (Gen)

replaced with distance relays for good protection co-ordination on 220 KV Grid.

30.12.2014.

Carrier protection should be kept in service for the feedershaving no Carrier protection.

Will be Tested & Put into Service.

DC earth leakage should be arrested on top priority to avoid spurious trippings due to DC earth leakage.

NIT issued for replacement of DC earth fault relay by SE(E)S office. Replacement of MOM boxes at ODY will be completed within may 2014.

220 KV line feeders. Different type of Numerical distancerelays should be replaced in place of electromechanicalrelays

Preparation of tender specification &Obtaining administrative approval is underprogress.

Time synchronisation of the distance relays with GPS mayplease be reviewed.

Will be carried out

8 220KV Varahi (VUGPH Hosangadi) (gen)

1

Rajan

ANNEXURE VI (15/18)

High setting for the Bus bar differential protection i.e.,325V

Will be re-setted at the earliest

A/R Selection switch is kept in non auto mode for all 400KVlines

Will be resolved at the earliest

Dead 220VDC earth fault for both sets i.e., Positive to earth235V

Attended and there is no DC Earth Fault at Present.

GPS time synchronisation for all the relays & DR notcarried.

Will be carried out (OEM has already visited Twice).

Pole discrepancy relay setting kept 0.1 sec for all lines. Will be re-setted at the earliest

220VDC earth fault persisting with leakage current of15mA

Will be rectified at the earliest

PD settings for Munirabad, BTPS & Mehaboobnagar kept at0.1sec.

Already resolved

RTPS-Munirabad line Zone-II setting (26.880 Ohm) is morethan Zone-III (26.44Ohm)

Already resolved

No fault locator working for Munirabad & Mehaboobnagar Already resolved400KV RTPS10

9 400KV BTPS

2

than Zone-III (26.44Ohm)No fault locator working for Munirabad & Mehaboobnagarlines.

Already resolved

Disturbance Recorder communication is not working forMunirabad and Mehboobnagar lines.

Will be complied

DG Set is not extended to 400 KV Sub-Station. Will be complied Old Electro-magnetic relays can be replaced with Numerical relays. Will be complied

400KV RTPS10

2

Rajan

ANNEXURE VI (16/18)

KPCL Status of Phase II activities Annexure - IBSl No. Name of Substation Details of work Remarks

1 220KV BTPS 220KV Bus coupler not commissioned Will be commissioned

2 220kV Gerusoppa Dam PHCVT's to be provided for each phase of the transmission lines

Procurement action is under progress

Karwar 1 & 2 feeders having only R Ph CVT available (Y& B Ph CVT's are not available).


For Kaiga & Kodsalli feeders have only R&B CVT'savailable (Y Ph CVT not available)


Bus coupler & transfer bus are out of service, Buscoupler module on busbar protection panel is kept out ofservice.

Will be rectified

Double earthing of all the supportingstructures/elements is to be ensured & neutral of GT's &LA's should be exclusively earthed.

Free space is not available,howeverproblem will be solved

Bus coupler & transfer bus are out of service, Buscoupler module on busbar protection panle is kept out ofservice.

Will be rectified

i) Nagjhari Kodsalli line-I having only R-Ph CVT (Y & B PhCVT's are not available . ii) Nagjhari Kodsalli line-II CVT'sare not available. iii) Kodsalli-Kadra line having only R &B Ph CVt's (CVT's are not available). iv) Kodsalli-kaiga linehaving only R & B Ph CVT's (Y Ph CVT's are not available).


220KV Nagjhari-Ambevadi 1 & 2 lines does not haveCVT's on the line. Carrier tripping was not available forthese lines.


Remaining six 220KV lines have only one R-phase CVT &Y&B Ph CVT's are not available.


Synchronising of 220KV lines feeders is not being donewith synchronoscope, only generator transformer unitsare being synchronised.

Synchronization of line feeders is not beingdone with synchronoscope, as the same isnot required. It is true that, only generatortransformer units are being synchronized atNPH.

The Neutrals of generator transformers are not earthedexclusively and all LA's also not found to be earthedexclusively.

It is true that, neutrals of transformers andLA's at NPH are not exclusively earthed.Further, at this stage, it is not possible toprovide separate earthing as it is alreadyembeded.

The mulsifier system nozzles are not directed towardsPower transformer body in the middle.

Noted and the mulsifire nozzle are directedtowards power transformer body in themiddle.

5

220KV Nagjhari Power House

3

220KV Kadra (Gen)

4

Kodsalli s/s(Gen)

1

Rajan

ANNEXURE VI (17/18)

3 Core CT's to be replaced with 5 core CT's to keep theBus bar protection in full shape with both Main & CheckZone.


3 CVT's to be provided on all 220KV feeders so as to keepthe Main-II protections on Bus PT or CVT which increasesthe reliability of the protection system.


Bus bar protection panels to be replaced with newpanels of numerical relay type to have the bus barprotection in full shape with all features (Check Zone, CTfail, iso fail etc. features) as the existing scheme is nothaving check zone facility. Certain CT's with 3 coresshould also be changed to have 5 cores for bus barprotection.

Pre-commissioning tests are alreadycompleted. LC already awailed &commissioning of new Bus bar protectionpanel is under progress.

Feeders having same core for Main-I & Main-II should beseparated to individual core, i.e., Main-I & II should beon different CT cores.

Procurement of 245kV 5 core CT's is underprogress. The matter will be resolved afterErection & commissioning of 245kV CT'shaving 5 cores.

The battery bank-II to be replaced with VRLA(maintenance free) type batteries to increase therelaibility of DC system, as the existing both banks are oflead acid type are under complete deteriorationcondition.

Already solved by replacing with VRLA type1000Ah batteries on 06.01.2013 & 500Ahbatteries on 24.06.2013

All generator transformers OTI & WTI shall be brought tocontrol room for better monitoring of the transformerperformance.

The 4-20 mA temperature signals of GT1,3,5 & 8 have been provided to controlroom recorder for monitoring.Procurement of new guages withtemperatures for GT 2, 6 & 7 is in progress.GT 9 & 10 are being replaced & themonitoring facility will be extended afterreplacement.

New SF6 type circuit breakers may be replaced withoutdoor type CT's on either side of the breaker in place ofexisting BOCB as sectionaliser breakers are very vitalwhile clearing the very high level bus faults.

Already NIT No. LOT/CEED/SGS/245kVHybrid Bkr./4310 dtd:20.02.2014 issuedthrough e-portal & will be retrofitted at theearliest

6 220KV Sharavathy SS (Gen)

2

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ANNEXURE VI (18/18)

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ANNEXURE VII (1/9)

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ANNEXURE VII (2/9)

Anil

Typewritten Text

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ANNEXURE VII (3/9)

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ANNEXURE VII (7/9)

Anil

Typewritten Text

Annexure-B

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ANNEXURE VII (8/9)

Compliance of points pertaining to Kaiga as per PSAG-8 Recommendation Kaiga-34 response

To review direct trip send circuit at Kaiga end to prevent receiving of DT command continuously at Guttur end during over voltage tripping’s.

Direct trip signal from Kaiga end is extended to remote substation during LBB, over voltage and 86M1A and 86M2A relay operation. 86M1A and 86M2A relay also operates whenever direct trip is received from remote substation. To prevent continuous direct trip signal from Kaiga to remote substation, logic modification in trip lockout relay circuit will have to be made, this will result in bypassing of some of the line protections. Hence it is not possible to make any modification in existing scheme.

To trigger DR in case of over voltage start in their relays.

Presently KGS end DTR triggering is enabled whenever direct trip command is received from other station. KGS DTR has been made to trigger to record pre fault data for 500 mSec and post fault data for 1000 mSec. This data is being given in LONG WITH TRIP details.

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ANNEXURE VII (9/9)

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ANNEXURE V (72/72)

ANNEXURE VI

The constituents are requested to submit the following details for all 220 KV and above Substations / Transmission elements at the earliest.

I. Sub Station Protection Availability S. No.

State/ Utility

GENCO/ TRANSCO

Voltage level

Total no. of substations

Bus bar protection LBB protection Remarks

not available

available not available

available

in service

not in service

in service

not in service

II. Line Protection Availability S.No Name of Line Main 1 protn

(Yes/ No)

Main 2 protn (Yes/ No)

Single phase A/R facility (Yes/ No)

Carrier scheme (Yes/No)

Back up protn (Yes/No)

Over voltage protn (Yes/No)

Remarks

1 From end To end

2 From end To end

III. Loss of Load /Generation The Loss of Load /Generation in Million Units / MW affected due to Grid Disturbance /Grid Incidence.

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ANNEXURE VII

1

Follow up discussions (36th PCSC) - Annexure-II

I. GRID INCIDENTS (GI) S. No. Details of

Events Date and Time

Reason Category

1 400 kV Neyveli TS1 EXP- Trichy

14-08-2014 at 18:09 hrs

Both ends reported receipt of direct trip. The reason for direct trip needs to be furnished.

DT over NLC lines

NLC: o The problem could not be figured out; cable healthiness and wiring have been

checked; during the next shutdown it could be checked again. o All PLCC panels are old and PGCIL (Pondicherry) has given the letter to NLC for

changing the PLCC panels at their end. o Relays could be procured by PGCIL at a lesser price due to the high volume of

purchase from OEM and the cost would be shared by NLC. o On 5.11.2014 there would be shutdown on Bhaoor line for checking some wiring and

A/R issues. o For fixing the relays it would take another 3 months time.

SRLDC: o During transient fault over Trichy line, auto reclose could not be carried out at Trichy

due to receipt of DT from NLC end. o It has to be found out whether DT was sent by the relay or PLCC. o NLC shall decide whether to change the relay or PLCC. o The issue is not yet closed and NLC shall submit the remedial measures taken by next

PCSC meeting. o SR-II shall write a letter to NLC for changing the panels (relay). o NLC can also write a letter to PGCIL for changing their relay/PLCC panels. o PLCC at Salem, Pugalur, Pondicherry and Trichy line that have connection with NLC

have to be changed. o On Bahoor and Villianur lines from NLC TS-2 are without A/R feature.

KSEB:

o DT can be conditioned on another channel to avoid false tripping. PGCIL:

o 3-phase trip by distance protection shall not give DT to other end. SRPC :

o As PGCIL is asking for deemed availability, it has to take the concurrence of NLC for changing the relays.

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ANNEXURE VII

2

3 400 kV Khammam-Kalpakka line- 1

23-08-2014 on 18:24 hrs

Line tripped at Khammam end only on operation of distance Protection and was holding from Kalpaka end. The reason for operation of distance protection needs to be furnished

GI-2

PGCIL: o As the issue has been referred to OEM, further analysis could not be carried out. o Now it has been instructed to protection personnel not to remove neutral fuse while

checking the fuse failure conditions. o All numerical relays have fuse failure detection logic. o It is better to switch over to phase to phase voltage mode, to avoid nuisance tripping.

KSEB: o If capacitor C1 of CVT is damaged, the voltage reading would be erroneous. o In phase to neutral voltage mode, when neutral fuse is blown out/removed, an

artificial neutral is formed; then based on the capacitance between phase and earth, the voltage is disturbed.

SRLDC: o Either +ve or –ve sequence could be used in fuse failure detection logic.

KPCL: o Battery bank and battery charger have to be replaced. o In another 8 days it would be done.

5 ICT -1 & 2 at Guttur Substation

26-08-2014 at 13:44 hrs

ICT’s tripped on operation of Earth fault relay. Triggering incident was failure of Jumper in 220kV Guttur-Neelagunda line.

GI-2

8 Multiple Tripping at 400 kV Guttur station

12-09-2014 at 12:22 hrs

400kV Kaiga-I, Hiryur-I, Narendra-I & ICT-I tripped at Guttur station due to operation of bus bar protection of 400kV Bus-1 at Guttur. It was reported that the LBB protection acted due to wrong configuration of distance relay

GI-2

4 400kV Raichur-Mahboobnagar

25-08-2014 at 10:33hrs and 31-08-2014 at 19:44 hrs

Line tripped on operation of carrier lock out relay at Raichurand line was holding from Mahboobnagar end. The reason for operation of carrier lockout relay needs to be furnished

GI-2

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ANNEXURE VII

3

KPTCL: o P142 over voltage relay has been installed on Kaiga line-1 and line-2. The relay is

with higher DO/PU ratio and no undue over voltage tripping since replacement. o Two days back there was actual over voltage condition and the relays operated. o Oscillations are still there on 400 kV side at Guttur end of lines. o On 220 kV side oscillations are not there as it was checked by triggering 220kV side

DR by 400 kV O/V start condition. o GPS is not yet there at Guttur station. o PID (Puncture Insulator Detector) work tendering is going on for 400 kV Kaiga lines. o Jindal and Kaiga end could not observer any spikes on 400 kV voltags. Hiriyur is yet

to study the voltage pike phenomenon. SRLDC:

o On Kaiga-Guttur lines, O/V trippings have come down. o Voltage oscillations are not found at Narendra. o One of PGCIL’s spare PMU could be put up temporarily at Guttur for one month

for studying the oscillations. SRPC:

o Within 10 days, point-wise reply to protection audit points shall be submitted by KPTCL.

o Some mechanisms have to be in place to keep track of protection recommendations proposed by the forum in various meetings.

9 220kV Srisailam

right bank station 3-09-2014at 10:41 hrs

It was reported that trip wire to circuit breaker of 220kV Dindi-2 was open which resulted in operation of LBB protection and tripping of all elements connected to 220kV Bus-2.

GI-1

10 220kV Srisailam right bank station

3-09-2014 at 16:09

Mal-operation of LBB relay which resulted in tripping of all elements connected to 220kV Bus-1

GI-1

APGENCO: o CT has been replaced on unit-4 feeder. o GPS work is under progress. o High set O/C and E/F settings of GT have been revised.

KSEB: o High set is for protecting the transformer. o High set settings have to consider bus voltage, source impedance and half of

transformer impedance for calculating the fault current. o As the burning of unit-4 CT would have caused contamination in its vicinity,

neighboring CTs and other equipment have to be cleaned and subjected to tan delta checking before putting into service.

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ANNEXURE VII

4

NTPC: o If settings are not high enough, then far end faults also would be sensed and resulting

in tripping of transformer. SRLDC:

o At other stations of APGENCO /TSGENCO also, review of high set settings could be undertaken.

II. AUTO-RECLOSE (A/R) FAILURE/ NON-OPERATION DURING TRANSIENT FAULT

9 400kV

Arasur-Mettur Line I

29-09-2014 at 21:10 hrs

SRLDC: The line tripped two times and without A/R operating.

PGCIL: The bay belongs to

TANTRANSCO . A/R is on non-auto mode at

Arasur end following the settings at Mettur end which is also in non-auto mode.

Recommendation: Mettur S/s to Enable A/R Scheme.

o Before next meeting A/R feature has to be enabled on the line.

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