· pdf fileconstituents are requested to bring/ give full particulars for the tripping ......

SOUTHERN REGIONAL POWER COMMITTEE

BENGALURU

Agenda for the 47

th Meeting of Protection Coordination Sub-Committee of

SRPC to be held on 15.09.2015 (Tuesday)

1. Introduction

2. Confirmation of Minutes of last PCSC meeting

Confirmation of minutes of 46th

Protection Coordination Sub-Committee meeting

held on 30.07.2015.

3. Grid Occurrences (w.r.t. SRLDC)

3.1 Grid Disturbance (GD), Grid Incidences (GI), and trippings due to failure of Auto-

reclosing (A/R), and Mal-operation of PLCC equipment that occurred during the

last one-month period (July - August, 2015) would be discussed in the PCSC meeting [Annexure-I].

Constituents are requested to furnish the following information in respect of the

above grid occurrences to have fruitful discussions in the PCSC forum.

(a) Single line diagram of the station with switching devices, CT, PT and relay

details

(b) Cause of the tripping & Remedial Action taken

(c) Relay setting details

Constituents are requested to bring/ give full particulars for the tripping events

incident to their system.

3.2 In compliance of Regulations 5.2 (r) of IEGC – as per the provisions under clause

1.5 of IEGC 2010, the Constituents are requested to furnish the following information in respect of Grid Occurrences (Annexure-II) latest by 10.09.2015:

(a) First Information Report (FIR)

(b) Event Logger (EL) output

(c) Disturbance Recorder (DR) output

(d) Trip event analysis report (with pre and post fault system conditions)

Non-furnishing of Tripping details including Disturbance Recorder/Sequential

Event logger output would be discussed in the meeting.

4. Submission of reports/compliance by Constituents

4.1 Status of pending Protection Coordination Sub-Committee (PCSC)

Recommendations

Status of the pending PCSC recommendations (from 30th

PCSC to 45th

PCSC) given at Annexure-III may please be sent latest by 10.09.2015.

4.2 Remedial measures for "Transmission Line under Forced Outage"

The constituents are requested to send the remedial measures/ actions taken by them for the tripping events as circulated vide our emails. (Annexure-IV)

Agenda for the 47th Protection Coordination Sub Committee Meeting to be held on 15-09-2015 Page 2

The trip events are based on the daily reports at SRLDC website

http://srldc.in/DailyReport.aspx under the menu: Reports->Daily-> "TL under

Forced Outage")

4.3 Certificate for Healthiness of Batteries

As per the MoP direction given in pursuant to recommendations of the

Enquiry Committee (NEW grid disturbance on 30th

& 31st July, 2012), RPC’s

are required to obtain from their respective Constituents the monthly

certificate for healthiness of batteries, installed at 220 KV and above voltage

level Substations (for power supply to Relays, RTUs and PLCC equipment)

and furnish the same to CEA/ MoP.

With reference to above, the Constituents are requested to submit the

certificate on healthiness of batteries on monthly basis (i.e. on 7th

day of the

month) to SRPC.

The sought status for the month of July, 2015 is still awaited from the

following SR-Constituents:

APGENCO (Thermal), APTRANSCO, TSGENCO (Hydro), KPTCL,

TANGEDCO, KSEB, PGCIL (SR-I&II), NTPC (Ramagundam,

Kayamkulam), NPCIL (Kudankulam), NTPL, CEL, CEPL & TPCIL.

5. Reviewing of Zone-3 Philosophy of transmission lines protection

The general philosophy to be followed for Zone-3 settings in SR had been discussed in

the Sub Group meeting of PCSC held on 20-11-2013 and finalized during PCSC-26 held on 21.11.2013 (Annexure-V). However, as it was noticed that there exist minor

differences in the Impedance settings adopted for Zone-3 by the SR –Constituents vis-à-

vis the Rama Krishna Committee’s (Task Force on the Power System Analysis under

Contingencies) guidelines w.r.t. Zone-3, it is proposed to hold a discussion in this regard

to elicit the views of SR-Constituents.

Relevant extracts from the Appendix - 9.1 of Report of the Task Force on Power System

Analysis under Contingencies brought out in August, 2013 (available at

http://www.cea.nic.in/reports/articles/god/report_power_system_analysis.pdf): 3. ZONE-3 REACH SETTING

Zone-3 distance protection can offer time-delayed remote back-up protection for an adjacent transmission circuit. To achieve this, Zone-3 distance elements must be set according to the following criteria where possible. Zone-3 should overreach the remote terminal of the longest adjacent line by an acceptable margin (typically 20% of highest impedance seen) for all fault conditions. Set KN as (Z0 – Z1) / 3Z1.

However, in such case where Zone-3 reach is set to enter into next lower voltage level, Zone-3 timing shall be coordinated with the back-up protection (Directional over current and earth fault relay) of power transformer. Where such coordination cannot be realized, it is recommended to carry out simulation studies for relay reach & time coordination and suitable solution may be devised. Some of the typical solution can be like application of back up distance protection for power transformer, duplicated protection for downstream 220kV feeders or special protection scheme logic. Similar issues, if encountered for Zone-2 reach setting, should also be addressed in the above manner.”

http://srldc.in/DailyReport.aspx


6. ZONE-3 TIMER SETTING Zone-3 timer should be set so as to provide discrimination with the operating time of relays provided in subsequent sections with which Zone-3 reach of relay being set, overlaps. Typical recommended Zone-3 time is 0.8 to 1.0 second. For Special cases, where co-ordination between long and short lines is required, following formula would be the basis for determining the minimum acceptable Zone-3 time setting:

tZ3 > tMA + tCB + tZ3reset + tS

Where: tZ3 = Required Zone-3 time delay tMA = Operating time of slowest adjacent circuit local back-up protection tCB = Associated adjacent circuit breaker clearance time tZ3reset = Resetting time of Zone-3 impedance element with load current present tS = Safety margin for tolerance (e.g. 50 to 100milliseconds)

7. LOAD IMPEDANCE ENCROACHMENT With the extended Zone-3 reach settings, that may be required to address the many under reaching factors already considered, load impedance encroachment is a significant risk to long lines of an interconnected power system. Not only the minimum load impedance under expected modes of system operation be considered in risk assessment, but also the minimum impedance that might be sustained for seconds or minutes during abnormal or emergency system conditions. Failure to do so could jeopardize power system security. Ideal solution to tackle load encroachment may be based on the use of blinders or by suitably setting the resistive reach of specially shaped impedance elements or by use of polygon type impedance elements. It is recommended that all the distance relays should have quadrilateral / polygon characteristic. For relays having Mho characteristics, it is desirable to have load encroachment prevention characteristics or a blinder. In the absence of credible data regarding minimum voltage and maximum load expected for a feeder during emergency system condition, following criteria may be considered for deciding resistive reach / blinder setting to prevent load point encroachment:

Maximum load current (Imax) may be considered as 1.5 times the thermal rating of the line or 1.5 times the associated bay equipment current rating ( the minimum of the bay equipment individual rating) whichever is lower. (Caution: The rating considered is approximately 15 minutes rating of the transmission facility).

Minimum voltage (Vmin) to be considered as 0.85pu (85%).

For setting angle for load blinder, a value of 30 degree may be adequate in most cases.

For high resistive earth fault where impedance locus lies in the Blinder zone, fault clearance shall be provided by the back-up directional earth fault relay.

6. Grid Study Committee (GSC): Data Inputs for Task-2

For facilitating the audit-check of the 15 Stations in SR by the Consultant under Task-2,

respective Constituents have been provided with (i) a Check-list for Data Collection

(CHECK-LIST), and (ii) Details pertaining to Bus Bar protection and Breaker Failure

Protection (BBP-BFP), and requested to kindly furnish the duly filled CHECK-LIST and

BBP-BFP details for the Stations under their control area latest by 31.08.2015 to SRPC


([email protected]) so that the same can be forwarded to the Consultant. As

the data in this regard is yet to be received from majority of the concerned Constituents,

they are requested to expedite the same.

7. Network Configuration changes

As per the information furnished by SR-Constituents to the OCC forum in their 109th

Meeting held on 08.07.2015 (Minutes circulated on 27.07.2015), the following network

configuration changes (additions/ deletions/ modifications of transmission elements) took

place in the southern grid during the month of June-July, 2015.

COD of NTPL U-I (500 MW) had been declared from 18th June 2015.

COD of NLC II Expn U- I (250MW) had been declared from 05th July 2015.

400kV Karaikudi - Pugalur D/C line was charged first time on 06th July 2015 by

TANTRANSCO

11.35 MW Wind Generation capacity was added in Tamil Nadu during the month of

June, 2015.

10 MW Solar Generation capacity at Sivasamudram was added in Karnataka by

KPCL on 16.06.2015.

8. Protection Logic checking of Critical Substations

Logic checking of following Critical Substations in the Southern Region had been

approved in the SRPC meeting held on 18.05.2013 at Bangalore.

(i) 400 kV Guttur (vi) 400 kV Kurnool

(ii) 400 kV Ramagundam (vii) 400 kV Almatti

(iii) 400 kV Kalpaka (viii) 220 kV Edamon

(iv) 400 kV Nelamangala (ix) 400 kV VTS

(v) 400 kV Hoody (x) 400 kV Vemagiri

9. Compliance of Hon’ble CERC Orders.

9.1 Petition No. 146/MP/2013 with I.A. 36/2013: Order dated 20.02.2014

Compliance of Regulations 5.2 (r) of the Grid Code: Issue regarding non-

furnishing of FIR / Trip Analysis Report, EL, DR, etc. was also

highlighted. It is pointed out that the above reports are to be submitted /

uploaded on SRLDC web application within 24 hours as mandated under

IEGC / CEA Regulations.

Implementation of Phase-I and Phase-II of Protection Audit

Recommendations: All the constituents are requested to 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.

Compliance of Regulations 5.2 (e) & 5.2 (l) of the Grid Code and Regulation

3(1)(e) of CEA Grid Standards: The constituents are requested to strictly

comply with these provisions by ensuring standard protections systems having

the reliability, selectivity, speed and sensitivity to isolate the faulty equipment

and protect all components from any type of faults, within the specified fault

clearance time and providing protection coordination

Ensuring proper maintenance of transmission lines and adopting best O&M

practices: The constituents are requested to conduct line patrolling regularly

mailto:[email protected]


as per the SRPC transmission line patrolling guidelines (available under the

menu item "All Uploads Operation Miscellaneous Transmission Line

Patrolling Protocol / Guidelines for Southern Region" on SRPC website).

(http://www.srpc.kar.nic.in/website/2014/operation/patrolling.pdf).

9.2 Petition No. 167/Suo- Motu/2012: Order dated 22.02.2014

The Constituents are requested to follow approved protection philosophy

ISTS licensees are requested to submit details of updated distance protection relay

setting of all inter-regional lines to POSOCO & RPCs.

All SLDCs are requested to install/activate sound recording system in their control

rooms within three months from the date of issue of this order.

The Constituents are requested to submit the progress of implementation to

SRPC and SRLDC as specified in the Hon'ble CERC Order.

9.3 Petition No. 263/MP/2012: Order dated 19.12.2013

Constituents are requested to implement the quantum of relief by AUFR and df/dt

relays by identifying additional feeders and keep them functional within one month

of issuing this order.

SLDCs are also requested to map these relays on their respective SCADA

system within three months of issuance of this order.

The Constituents are requested to submit the progress of implementation to

SRPC and SRLDC as specified in the Hon'ble CERC Order.

9.4 APTRANSCO’s Petition No.95/MP/2015: Date of hearing 09-04-2015

It was noted in the Analysis and Decision part of the Order that:

“8. Noting the submissions of the petitioner, SRPC and SRLDC and activities

initiated by the petitioner for procurement of materials required for

implementation of the remarks of protecting audit, we allow time to the

petitioner till 31.12.2015 for completion of our directions in Order dated

19.12.2013 in Petition No. 146/MP/2013.”

“9. SRPC is directed to monitor the status of completion of works relating to

protection audit remarks in respect of 7 nos 400 kV sub-stations and 11 nos

220 kV sub-stations of APTRANSCO, protection audit remarks in Protection

Coordination Sub-Committee (PCSC) meetings and coordinate the periodic

protection audit to be carried out in Southern Region after deliberation in

SRPC and submit bi-monthly report to the Commission.”

9.5 TSTRANSCO’s Petition No.83/MP/2015: Order dated 14-05-2015

It was noted in the Order that:

“12. Noting the submission of the petitioner, SRLDC and SRPC and

considering the actions already initiated by the petitioner for implementation

of works relating to protection audit, we allow time till 31.10.2015 and

31.8.2016 for implementation of Phase-I and Phase -II works respectively.

The petitioner is directed to submit affidavit confirming the completion of

Phase I of protection audit remarks by 31.10.2015 and Phase-II of protection

audit remarks by 31.8.2016.

13. SRPC is directed to monitor the status of completion of remarks in these

substations vis-à-vis protection audit remarks in Protection Coordination Sub

Committee (PCSC) meetings. SRPC is further directed to coordinate the

http://www.srpc.kar.nic.in/website/2014/operation/patrolling.pdf


periodic protection audit to be carried out in Southern Region after

deliberation in SRPC.”

9.6 Order in Petition No. 86/MP/2014 and 374/MP/2014: Order dated 18-08-2015

A copy of the above Order dated 18.08.2015 is given at Annexure-VI. The time-

lines given to the various SR-Constituents for completion of Phase-I and Phase-II

activities of Protection Audit Recommendations are given below:

(A) KSEBL:

18. Noting the submission of KSEBL, SRLDC and SRPC and considering the actions

already initiated by KSEBL for implementation of remarks of protection audit, we

allow time till 31.12.2015 and 31.3.2016 for implementation of Phase-II works

and R&M works at Idduki HEP respectively.

(B) TANTRANSCO: 21. After considering the submissions of TANTRANSCO, SRLDC and SRPC, it is noted

that TANTRANSCO`s request for time till 31.5.2015 for implementation of Phase–I

activities of providing numerical relays for feeder protection and Auto transformer

protection is already over. We allow time till 30.6.2016 for other Phase-I activities

such as provision of line VT, 5 core CT, Time synchronizing with GPS, Disturbance

recorder & event logger and Phase-II activities. According to SRLDC, total

implementation period is 15 to 16 months for items which involve major

procurement, design changes with major site modification/civil activities.

Accordingly, we allow 16 months time i.e up to 30.11.2016, for Renovation and

Modernization of Singarpet, Singaperumalkoil, Salem and Tondiarpet 230 kV sub-

stations from the issue of the order.

(C) NLC:

22. NLC has sought time upto 31.12.2014 and 31.3.2015 for completion of Phase-I work

of Numerical Relay Retrofitting and for Phase-II works of providing second battery

bank of PLCC respectively. It is noted that the completion dates for Phase-I and

Phase-II of protection audit remarks as requested by NLC are already over.

Therefore, no direction is required in this regard. However, we direct NLC to file a

confirmation report regarding completion of protection audit works for Phase-I and

Phase-II.

(D) KPTCL:

23. …

…

Considering the submission of KPTCL and SRLDC, we allow time to KPTCL time till

15.01.2016 for completion of Phase-I and Phase-II of protection audit remarks. No

further extension shall be granted in this regard.

(E) KPCL:

24. …

… Considering the submission of KPCL and SRLDC, we allow time to KPCL till

31.10.2015 and 31.12.2015 for completion of Phase-I for Phase-II of protection

audit remarks respectively. No further extension shall be granted in this regard.

26. We direct SRPC to (a) submit status of protection audit remarks in respect of

APGENCO, NTPC (SR), Talcher, Puducherry, PGCIL (SRTS I & II), MAPS and


TANGEDCO, (b) monitor the status of completion of remarks of protection audit in

respect of all constituents of Southern Region in Protection Coordination Sub-

Committee (PCSC) meetings, and (c) to coordinate periodic protection audit to be

carried out in Southern Region after deliberation in SRPC. All the constituents of

Southern Region are directed to file their status with SRPC on regular basis to

facilitate proper monitoring in PCSC meetings. SRPC is directed to submit bi-

annually status report to the Commission confirming the completion of Phase-I,

Phase-II and R&M works of protection audit remarks of the constituents of Southern

Region.

In compliance of above Order, APGENCO, NTPC (SR), Talcher, Puducherry,

PGCIL (SRTS-I)& PGCIL (SRTS-II), MAPS and TANGEDCO are requested to

furnish the recent status of protection audit remarks (both Phase-I & Phase-II) by

15.09.2015 for submitting a proper reply to the Hon’ble Commission.

10. Other Protection Issues, if any, with the permission of the Chair

11. Sending Agenda items for the PCSC meetings

As per the Guidelines of CEA/MOP, it has been decided to conduct the PCSC

meetings on monthly basis. It is requested that Agenda Items for the PCSC meetings,

if any, may please be sent latest by 5th

working day of the month to SRPC Secretariat

to compile and circulate the same so as to have fruitful discussions in the PCSC

meetings.

12. Date of next PCSC meeting

The 48th

PCSC meeting would be conducted on 29.10.2015 (Thursday) at SRPC,

Bangalore.

*******

Annexure- I

Page 1 of 5

Grid Occurences

1. ग्रिडडडस्टर्बन्स / ग्रिडइन्सडन्टकावििरण - Details of Grid Disturbances:

Sr. No.

क्र.सं. घटनाकावििरण /

Details of Event

तारीख/ Date &

समय /Time कारण / Reason

टटप्पणी /Remarks

शे्रणी/ Category

1

Tripping at

Srisailam left bank

power station

18-08-2015

at 15:25 hrs

400kV Srisailam-Mamidapalli

line-2, 400kV Srisailam-

Satenapalli line-2 and 400 kV

Srisailam-Kurnool line tripped

during multiple tripping at

Srisailam power station. 400kV

Srisailam-Mamidapalli-1 and

400kv Srisailam-Satenapalli-1

was kept out of service due over-

voltage conditions. There was no

generation at Srisailam left bank

power station. Triggering

incident was failure of CT in

400kV Srisailam-Satenapalli

line-2 at Srisailam end.

GD-1

Annexure- I

Page 2 of 5

2. ग्रिडडडस्टर्बन्स / ग्रिडइन्सडन्टकावििरण - Details of Grid incidents:

Sr. No.

क्र.

सं.

घटनाकावििरण / Details

of Event





1

Tripping of HVDC Bhadrawati pole-1& 2

14-017-2015 at 11:01 hrs

HVDC pole -1&2 tripped due to failure of auxiliary supply

GI-2

2

Tripping of 400kV

Gajwel-Hyderabad

line at 18-07-2015

at 2:16 hrs

Line tripped ay Hyderabad end on

mal-operation of reactor

protection at Hyderanbad end and

direct trip was sent to Gajwel.

However line was holding from

Gajwelend .

3

Tripping of 400/220kV ICT-5 at Ramagundam

22-05-2015 at 1:30 hrs ICT-5 tripped on PRD operation.

4

Tripping of 400kV

Udumalpet-

Tirunelveli line-2 28-07-2015

at 16:48 hrs

B-phase to earth fault had

occurred in line. It was observed

that 270ms aftr occurrence of

fault, over voltage stage-2

operated at Trirunelveli and

udumalpet ends which resulted in

tripping of line.

5 Tripping of 400kV

Guttur-Hiryur line-1 29-07-2015

at 11:08 hrs

line tripped at Guttur end due to

PT fuse failure during PT supply

change over. Direct trip was

received at Hiryur end. Similar

tripping had occurred at 17:54 hrs

on 18-05-2015.

6

Tripping of 400kV

Khammam-KTPS

line-2

30-07-2015

at 6:08 hrs

Y-phase to earth fault had

occurred in line. From Khammam

end DR it was observed that the

relay after dead time tried for

auto-reclose. The fault was

persisting and relay gave a single

phase trip instead of a 3 phase trip

after 1.25 sec. R& B pole voltage

dip after 2 sec possibly due to

operation of pole discrepancy.

Auto-reclose close command

observed after 2.5 seconds and all

poles got closed.

7

Tripping of 220kV

Kadra-Karwar line-

1&2 and 220kV

Kaiga-Kadra line

31-07-2015

at 11:44 hrs

220kV KAdra-Karwar lines-1&2

tripped on earth fault in B-phase

in zone-2. Kaiga-Kadra line

tripped at Kaiga end only on

operation of directional eath fault

Annexure- I

Page 3 of 5

protection.

8

Tripping of HVDC

Bhadrawati Pole-2

03-08-2015

at 02:01 hrs

Pole-2 tripped on “VCC2.MAIN

CIRCUIT FULL FLOW - V-

LOW” alarm. Heavy leakage of

Demineralised (DM) water

occurred in the Valve Cooling

System.

9

Tripping of 400kV

Coastal-NTPL line

and running units at

NTPL

03-08-2015

at 15:43 hrs

R-phase to earth fault had

occurred in 400kV Coastal NTPL

line. Line auto-reclosed at NTPL

end and failed to reclose at Coatal

end. Auto reclose block was

persisting due to PLCC channel

fail. Also running Units-1&2 at

NTPL tripped on operation of GT

differential protection.

10

Tripping of 400/220

kV ICT-2 at

Gazuwaka

(Vishakapatnam)

04-08-2015

at 12:49 hrs

ICT-2 tripped on operation of

220kV Bus bar protection of

220kV Bus bar-2 at 220kV VSS

station of APTRANSCO.

11

Tripping of HVDC

Bhadrawati Pole-1

05-08-2015

at 10:53 hrs

Main pump-2 of valve cooling got

tripped during dip in 33kV

auxiliary bus voltage. Valve

cooling flow got reduced due to

tripping of pump and resulting in

tripping of pole-1

12

Tripping of 400kV

VTPS-Satenapalli

line-1

05-08-2015

at 23:48 hrs

Line tripped on direct trip receive

at Satenapalli end.

13

Tripping of Unit-

1&2 along with

400/220kV ICT-2 at

Raichur TPS

06-08-2015

at 4:51 hrs

220kV RTPS-Lingasugur line-2

tripped at TPS end on operation of

distance protection zone-1.

400/220kV ICT-2 got tripped on

operation of earth fault protection.

220kV RTPS-Lingasugur line-

1&3 tripped on distance

protection zone-2 and zone-3

respectively. Due to tripping of

ICT-2, the running units got

overloaded and it was mentioned

that under frequency occurred as

units are on load control. The

Units got tripped on under

frequency. D

14

Tripping of 400kV

Talaguppa-

Neelamangala line

13-08-2015

at 12:57 hrs

and 19-08-

2015 at 19:30

hrs

Reason for tripping needs to be

furnished. FIR, DR/ EL not

provided

Annexure- I

Page 4 of 5

15

Tripping of 400kV

Hassan-UPCL line-2

17 Aug 2015

at 22:53 hrs

and

16thAugust

2015 at 3:01

and 23:59 hrs

Line tripped on operation of over-

voltage protection at UPCL end

on both days. However D.R / EL

of Hassan station was not

furnished to validate the same.

16

Tripping of 765kV

Kurnool-NPS line-1

19-08-2015

at 13:43 hrs

line tripped on operation of line

reactor R –phase WTI at Kurnool

end and direct trip was received at

NPS end.

3. Failure or non-operation of Auto reclose during transient fault

Sr. No.

Element Date & Time

Reason

1

Tripping of 400kV Khammam-

Kalpakka line-1

13-07-2015 at

12:12 hrs

Y-phase to earth fault occurred in

line. Line auto-reclosed at

Kalpakka end and failed to auto-

reclose at Khammam end

2

Tripping of 400kV Vemagiri-

GVK line-2 16-07-2015 at

17:02 hrs R-phase to earth fault had

occurred in line. Line auto

reclosed at Vemagiri end and

failed to reclose at GVK end

Tripping of 220kV Chikodi-

Mudshingi line

17-07-2015 at 5:01

hrs

line tripped on a R-phase to earth

fault and line tripped from both

ends. line did not auto-reclose

3

Tripping of 400kV Chikodi-

Talandage line 21-07-2015 at

17:15 hrs line tripped on R-phase to earth

fault and line tripped at both ends.

line did not auto-reclose

4 Tripping of 220kV Sedam-

Tandur line

23-07-2015 at 11:30 hrs

Line tripped on earth fault. Line

did not auto-reclose

5

Tripping of 400kV Pugalur-

Karaikudi line

at 18:40 hrs on 23-

07-2015

Line tripped on a B-phase to earth

fault. Line tripped due 2nd fault

in B-phase within reclaim time.

At karaikudi Main CB did not

reclose during 1st fault and tripped

on PD.

6

Tripping of 400kV Kayatahr-

Karaikudi line

26-07-2015 at

18:26 hrs

Y-phase to earth fault had

occurred in line. Line auto-

reclosed at Karaikudi end and did

not reclose at Kayathar .

7

Tripping of 220kV Ambewadi-

Ponda line-2

02-08-2015 at

13:20 hrs

Line tripped on a transient fault in

B-phase. There is no provision

for auto reclose.

8

Tripping of 400kV Kaiga-

Guttur line-1

07-08-2015 at

11:19 hrs


fault. Line tripped as there is no

provision for auto-reclose

9 Tripping of 220kV Ambewadi-

Ponda line-1

08-08-2015 at

10:51 hrs and 09-


fault. Line tripped as there is no

Annexure- I

Page 5 of 5

08-2015 at 11:15

hrs

provision for auto-reclose

10

Tripping of 400kV

Vijayawada-Nellore(AP) line-3

15-08-2015 at

14:04hrs and 15:40

hrs


fault. Line did not attempt for

auto-reclose at Vijayawada

11

Tripping of 220kV Ambewadi-

Ponda line-1

17-08-2015 at

13:20 hrs

Line tripped on a transient fault .

There is no provision for auto

reclose.

12

Tripping of 400kV

Vijayawada-Nellore line-2

20-08-2015 at

20:53 hrs


fault. Line auto-reclosed at

Vijayawada end and line did not

reclose at Nellore end.

13

Tripping of 220kV Sabarigi-

Theni line

16-08-2015 at

12:15 hrs and 17-

08-2015 at

10:02hrs

Line tripped o earth faults.

Attempt for Auto reclose could

not be established

4. Lines tripping due to tripping at one end/PLCC mal-operation

Sr. No.

क्र.

सं.

घटनाकावििरण / Details

of Event





1

Tripping of 400kV

Kayathar-Karaikudi

line-2 26-07-2015

at 23:03 hrs

Line tripped on operation of

overvoltage protection at

Karaikudi end. Over voltage

protection was found to be in

order. However voltage was

continuously observed in D.R of

Karaikudi station.

2 Tripping of 400kV

RTPS-YTPS line

20-08-2015

at 00:14 hrs

Line tripped at RTPS end only

Annexure- II

1 / 18

Annexure- II

2 / 18

Annexure- II

3 / 18

Annexure- II

4 / 18

Annexure- II

5 / 18

Annexure- II

6 / 18

Annexure- II

7 / 18

Annexure- II

8 / 18

Annexure- II

9 / 18

Annexure- II

10 / 18

Annexure- II

11 / 18

Annexure- II

12 / 18

Annexure- II

13 / 18

Annexure- II

14 / 18

Annexure- II

15 / 18

Annexure- II

16 / 18

Annexure- II

17 / 18

Annexure- II

18 / 18

Meeting

No /

Index

Details of

Event

Date Reason PCSC Recommendations Utility

Responsib

le for

implemen

tation

Status of Recommendations

as on 04.08.2015

Remarks

45/II/14 Tripping

of

400/220

kV ICT-

1&2 at

Gooty

substation

31-05-2015at

06:37 hrs

As per FIR, ICT-1&2

tripped on operation of

directional overcurrent

and earth fault

protection. It was

reported that there was

fault in 220kV

APTRANSCO system

1. APTRANSCO to check resistive reach of the

distance relays on 220 kV Gooty SS – Gooty RS

line

2. APTRANSCO to check time coordination of

distance relay on Gooty SS – Gooty RS line at

Gooty SS with Gooty ICT’s (1 & 2) back-up

protection.

APTRAN

SCO

Yet to be informed Pending

44/III/2 Tripping

of 400kV

Ghanapur-

Mamidap

alli

line

15-04-2015

at 2:03 hrs

Line tripped at

Mamidapalli end only

and was holding at

Ghanapur. Overvoltage

protection had operated

at Mamidapalli

TSTRANSCO to make DR

functional at Mamidipalli

TSTRAN

SCO

TSTRANSCO informed vide their mail dated 24.06.15 that the

existing relays would be replaced with numerical relays in DPR

works.

Pending

Pending Implementation of PCSC Recommendations (30th to 45th)

Andhra Pradesh

Telangana

Karnataka

42/II/3 Outage at

Regulapa

du

station of

APTRAN

SCO

21-02-2015

at

00:49 hrs

Y-Ph Metering PT

failed at 220KV

Ragulapadu Substation.

Fault got cleared

by tripping of lines from

remote ends.

APTRANSCO to furnish the remedial

measures taken in consequent to the tripping

incident along with the status of bus bar

protection and bus coupler at Regulapadu S/s.

A/R feature to be enabled on Regulapadu –

Alipuira 220 kV inter-state line.

APTRAN

SCO

Mail received on 27-05-2015:

1)Failed metering PT was replaced with new PT.

2) 220kV Ragulapadu is a single bus system. Hence there is no

provision for bus coupler at Ragulapadu SS.


APTRANSCO Vide Ltr. Dt. 23/06/2015, requested KPTCL to

furnish the details of available tele protection equipments and

details of the equipments going to be procure for enabling the

carrier aided protection on 220KV Ragulapadu-Alipura line. Based

on the KPTCL information we will take further necessary action.

Mail recieved on 22-08-2015:

APTRANSCOhas planned to commission ABB make ETL-41 type

PLCC terminal along with NSD-50 type protection coupler at

Ragulapadu end towards Alipura. vide our Ltr Dt 23-07-2015, it is

requested KPTCL to arrange ABB make ETL-41 cabinet with

NSD-50 type protection coupler for establishing PLC

communication between Alipura- Ragulapadu.

Pending

Annexure- III

1 / 20

A fault had occurred in

220 kV Kadra and

Kodasalli. As A result,

de-energization of

220kV bus occurred at

Kadra and

Kodasalli.

13-11-2014

at 19:31hrs

GD-1 at

Kadra and

Kodasalli

hydro

power

station

38/GD/3

.5

1. A/R for 220kV lines enabled already.

2. Shut down of lines availed to commission the auto reclosing

schme for 400 kV line at BTPS.


P.O. placed for procurement of timers for A/R function. Work

shall be completed by July 2015.


P.O. placed for procurement of timers for A/R function. Work

shall be completed by August 2015.

A/R at BTPS end to be made operational

within one month

KPCLTransient fault in R-

phase.

Line did not auto

reclose

26-06-2014 Pending400kV

Raichur-

BTPS line

34/III/1


1) e-NIT floated on 28.07.2014 for procurement of Numerical

distance relays & GPS. As there is change in scope of work and

quantity of relays by more than 25%, which is not permitted as per

KTPP act. Hence, tender cancelled and refloated on 05.05.2015

with revised scope of work and revised PQR.

2. However, as per the recommendations of PSAG, Relays

were temporarily rearranged, replaced and wired up. testing &

commissioning shall be completed with the assistance of KPTCL.


1. Cover -1 of the bid is scheduled for open eing on 25.06.2015.

2. As per the recommendations of PSAG, Relays were temporarily

rearranged. testing & commissioning completed with the assistance

of KPTCL.

PendingKPCL1. The PCSC forum requested KPCL to speed

up the installation of Numerical Distance

Protection relay in Kadra –Kaiga and

Kodasalli –Kaiga.

2. The PCSC forum requested KPCL to submit

the implementation status of PSAG-10

recommendations within a week’s time.


1. e- Tender folated for the retrofit of existing static relays with

Numerical version for lines M.nagar,M.bad,ICT-1 & 2 -Technical

Bid & Price bid opened . Bid evaluation and approval to place

P.O. is in progress.

2. Retrofit of existing bus bar (CAG-34) with numerical version -

Budgetetory offers obtained and is in process.

3. Order placed on M/s Siemens to replace relays. The work will

be Completed by May - 2015.


1. Retrofit of existing static relays with Numerical version for lines

M.nagar, M.bad and ICT- 1 & 2 -- Inspection of the Numerical

relays at M/s Siemens works completed on 11-06-2015 and

Dispatch clearance has been issued. Materials received.

2. Retrofit of existing bus bar (CAG-34) with numerical version –

Budgetary offers obtained and is under process.

KPCLThe PCSC forum recommended for

replacement of existing electromechanical

relays with Numerical relays.

Spl meeting held at

RTPS on 13th

and 14th

March 2014

Mar-14RTPS

Tripping

incidents

and the

Spl

meeting

held at

RTPS on

13th and

14th

March

2014

30/I/A Pending

Annexure- III

2 / 20

Circuit breaker of

400kV Guttur-Hiriyur

line-1 failed at Guttur

end while availing

shutdown for

replacement of CVT.

The

failure of breaker

caused bus fault at

Guttur.

KPTCL was requested to expedite the early

implementation of pending recommendations

of:

1. Protection Audit (Phase-I & Phase-II)

2. PSAG-4, PSAG-5, and PSAG-8

KPTCL Mail received on 27-05-2015 & 29-07-2015:

Latest satus of implementatin of Phase-1 &2 recommendations,

PSAG 4,5 and 8 is being obtained from field. The Status will be

updated witin a weeks time.

Pending05-11-2014

at 11:42 hrs

GD-1 at

Guttur

Substation

of KPTCL

38/GD/3

.2

38/GD/3

.1

GD-1 at

Mahaling

apura

Substation

of KPTCL

25-10-2014 Fault had occurred in

220kV

Mahalingapura-

Narendra line-2. Due to

the

failure of relay

operation at

Mahalingapura,

breakers at remote end

tripped which

resulted in bus dead

condition.

1. PCSC forum recommended KPTCL to

replace the old static distance protection

relays with numerical relays.

2. PCSC forum also requested KPTCL to

provide a broken conductor alarm indication in

Control Room.

3. Standing instruction needed to be given to the

all substation personnel for not changing the

relay settings without approval of RT/MRT

wing.

KPTCL Mail received on 27-05-2015 (KPTCL) & 29-07-2015:

1.Existing Back up relays will be replaced by numerical type

distance relays.Procurement is in tendering stage. Remaining

observations were attended.

Pending

34/I/6 400/220

kV ICT-1

& 2 at

MUNIR

ABAD

16-07-2014 As reported directional

over current relay of

ICT’s operated due to

snapping of line

jumper in 220kV

Lingapur line.

1. Bus bar protection shall be provided by

asset owner ( i.e KPTCL).

2. Settings for main distance protection &

Overcurrent protection shall be examined and

reviewed.

3. Time synchronization of the Substation

shall be ensured.

4. Correct DR shall be submitted to the SRLDC

for trip analysis.

KPTCL Mail recieved on 27-05-2015 (KPTCL):

1. KPTCL has taken action to provide bus bar protection to 220kV

buses.

2. Over current relay Settings of ICTs to be reviewed by PGCIL.

Mail received on 29-07-2015 (KPTCL):

Initial Tendering stage

A fault had occurred in

220 kV Kadra and

Kodasalli. As A result,

de-energization of

220kV bus occurred at

Kadra and

Kodasalli.

13-11-2014

at 19:31hrs

GD-1 at

Kadra and

Kodasalli

hydro

power

station

38/GD/3

.5

Pending


1) e-NIT floated on 28.07.2014 for procurement of Numerical

distance relays & GPS. As there is change in scope of work and

quantity of relays by more than 25%, which is not permitted as per

KTPP act. Hence, tender cancelled and refloated on 05.05.2015

with revised scope of work and revised PQR.

2. However, as per the recommendations of PSAG, Relays

were temporarily rearranged, replaced and wired up. testing &

commissioning shall be completed with the assistance of KPTCL.


1. Cover -1 of the bid is scheduled for open eing on 25.06.2015.

2. As per the recommendations of PSAG, Relays were temporarily

rearranged. testing & commissioning completed with the assistance

of KPTCL.

PendingKPCL1. The PCSC forum requested KPCL to speed

up the installation of Numerical Distance

Protection relay in Kadra –Kaiga and

Kodasalli –Kaiga.

2. The PCSC forum requested KPCL to submit

the implementation status of PSAG-10

recommendations within a week’s time.Annexure- III

3 / 20

39/I/5 Tripping

of

400/220k

V

ICT-2 at

Hoody

substation

of KPTCL

01-12-2014 Suspected mal-

operation of 220kV side

Rphase

over current relay

1. PCSC forum recommended KPTCL to

replace the relay with a different make.

2. KPTCL was also requested to train the O&M

personnel adequately before performing any

maintenance works to avoid such unwanted

trippings.

KPTCL Mail received on 27-05-2015 & 29-07-2015:

C&R panels of 500MVA ICT 1&2 will be replaced under

scheduled R&M works. O&M personnel are instructed to take

sufficient care in order to avoid unwarrented trippings.

Pending

40/IV/1 220kV

Sedam-

Tandur

line

20-12-2014

at 22:20 hrs

Line tripped on Yphase

to earth fault from both

the ends

KPTCL was requested to explore the possibility

of providing A/R feature to this line and

submit the remedial measures to the PCSC

forum.

KPTCL Mail recieved on 29-07-2015:

Carrier protection is being restored for 220kV Sedam-Tandoor line

at Sedam end. After restoring the carrier protection , AR will be

enabled.

Pending

41/I/1 GD-1 at

220kV

Kadra

power

Station of

KPCL

16-02-2015

at 12:56 hrs

Triggering incident was

B-phase to earth fault

had occurred in 220kV

Kadra-Kodasalli line.

Line tripped from

Kodasalli end only.

220kV Kaiga-Kadra

tripped in Zone-3 from

Kaiga end. Tripping of

evacuating lines caused

bus shut down at Kadra

hydro station.

1. KPCL to make functional the Main2

(EPAC) relay with the help of KPTCL at the

earliest.

2. KPCL to investigate the reason for DC

fuse fail during transient fault in 220kV Kadra-

Kodasalli line including the testing/ checking of

DC supply cables, breaker control cables, and

trip coils.

3. KPCL to ensure supply for Main-1& Main-

2 protections, Trip Coils (TC1, TC2) from

separate battery banks.

KPCL Mail received on 28-05-2015:

1. Main-2 relays already installed and commissioned.

2. DC fuses are intact. Till date no such incidence occurred.

3. Possibility of DC-1 & DC-2 arrangement and splitting of DC

will be reviewed.


1. Completed.

2. Completed.

3. Possibility of DC-1 & DC-2 arrangement and splitting of DC

will be reviewed.


1. In view of operating 220kV Ambewadi SS in split bus mode,

action is being taken up by KPTCL . Problem in the 220kV bus

coupler breaker is attended and isolator overhauling work is

under progress. Spilt bus operation at Ambewadi will be made

possible at the earliest.

2. ICT protection system at Ambewadi and trippings occured at

Supa GS during the instance is checked up and remedial measures

already furnished in this regard.


Action is being taken by KPTCL for operating Ambewadi in split

bus mode. Problem in bus coupler breaker is attended.Isolator

overhaulling work is completed.PTs are already provided to

220kV Bus-II. After commissioning of Bus-II PTs, Ambewadi

can be operated in split bus mode. Pending works will be

completed within a months time.

KPTCL1. Till the completion of R&M works for bus

bar and LBB protection, KPTCL shall explore

the possibility of having split bus operation

at Ambewadi and submit the details of the

same to PCSC forum.

2. KPTCL shall provide the details of the

tripping of Supa hydro station connected

downstream from 110 kV bus.

Triggering incident was

B-phase to earth fault in

220kV Ambewadi-

Nagzari line-1. B-pole

of breaker did not open

at Ambewadi end. LBB

protection not available

at Ambewadi end. All

elements tripped on

Zone-2 from remote

ends.

22-12-2014

at 21:22 hrs

GD-1 at

220kV

Ambewad

i Station

of KPTCL

40/I/1 Pending

Pending

Annexure- III

4 / 20

42/I/2

(GD)

Complete

outage of

220kV

Ambewad

i

substation

of KPTCL

12-03-2015

at 7:51 hrs

Fault in 220kV

Ambewadi-Nagjheri

line-2

1. KPTCL shall provide A/R feature on

Ambewadi – Ponda 220 kV D/C inter-state line.

2. Till the completion of R&M works for bus

bar and LBB protection, KPTCL shall explore

the possibility of having split bus operation at

Ambewadi and submit the details of the

same to PCSC forum.

KPTCL Mail received on 29-07-2015:

1. Procurement of Bus bar and LBB protection is in the final

tendering stage.

2. Action is being taken to restore the carrier protection for 220kV

Sedam-Tandoor line. AR will be enabled after restoration of

PLCC.

Pending

Mail received on 27-05-2015: 1. Bus Bar protection will be

provded under R&U.

2. A/R yet to be enabled.



tendering stage.

2. Action is being taken to restore the carrier protection for 220kV

Sedam-Tandoor line. AR will be enabled after restoration of

PLCC.

KPTCL1. KPTCL to provide Bus Bar protection and

LBB protection at Sedam S/s and furnish

the status of their implementation to PCSC

forum.

2. KPTCL to implement A/R feature on 220 kV

Sedam-Tandur inter-state line.

Fault occurred in 220kV

Sedam-Shahpur line

15-02-2015

at 14:24 hrs

Complete

outage of

220kV

Sedam

substation

of KPTCL

42/I/1

(GD)

Pending



tendering stage. 2. Action is being taken to restore the carrier

protection for 220kV Sedam-Tandoor line. AR will be enabled.



tendering stage.

2. Action is being taken to restore the carrier protection for

220kV Sedam-Tandoor line. AR will be enabled after

restoration of PLCC.

KPTCL 1. KPTCL to provide Bus bar and LBB

protections for 220 kV bus at Sedam S/s.

2. KPTCL to implement A/R feature on 220

kV Sedam-Tandur inter-state line.

R-Phase to ground fault

occurred on 220kV

Sedam-Shahpur line.

Fault not cleared from

Sedam end due to stuck-

breaker condition.

While the Sedam-

Sahapur line tripped

from Shahapur end in

Zone-1, the other 220

kv lines from Sedam

tripped at remote ends

in Zone-2. This caused

complete outage of

220kV Sedam

substation.

27-01-2015

at 8.00 hrs

Complete

outage at

220kV

Sedam

Substation

of KPTCL

(GD-1)

41/I/4 Pending


Carrier protection is put in to service. AR will be enabled at the

earliest.


Action is taken for enabling AR for Mudashinge and Talandage

lines. Work is scheduled during first week of August 2015.

KPTCL1. KPTCL to provide A/R feature on the 220

kV Chikkodi – Talandage, and 220 kV

Chikkodi –Mudashinge inter-state lines.

2. KPTCL to carry out E/F relay coordination

for Chikkodi - Talandage and Chikkodi –

Mudashinge lines in coordination with

Maharashtra.

Lines tripped during test

charging 220kV

Chikodi-Belgaum line-2

from Chikodi

end.

20-02-2015

at

06:40 hrs

Tripping

of 220kV

Chikodi-

Talandage

and

220kV

Chikodi-

Mudshing

i line

42/II/2 Pending

Annexure- III

5 / 20

43/II/14 Tripping

of

400/220k

V ICT-1

at

BTPS

14-01-2015

at 1:09

hrs

ICT tripped due to

operation of Over

current and Earth fault

relay

KPCL to check the possibility of providing line

differential protection between RTPS and

Yermarus stations.

KPCL KPCL vide their mail dated 07.07.2015 informed that revised relay

settings would be incorporated in co-ordination with KPTCL.

Pending

44/II/10 Tripping

of 400kV

Raichur-

RTPS line-

2

26-04-2015

at 18:01

hrs

Line tripped on

operation of overvoltage

protection at RTPS.

Line was

holding from Raichur

(PG)

KPCL to check the drop off to pick up ratio of

the OV relay at RTPS end.

KPCL Mail received on 07.07.2015:

Same will be checked during next shutdown.

Pending

220kV Kodasalli-

Nagjheri line-1 tripped

from Kodasalli end on

operation of

distance protection,

zone-2.

220kV Kodasalli-

Nagjheri line-1&2 is

kept opened from

Nagjheri end, hence

fault

could not be cleared

with carrier aided

protection. Backup

earth fault relay at

Kaiga end got operated

during the event and

resulted in tripping of

220kV Kaiga-

Kodasalli line from

Kaiga end.

22-04-2015

at

20:28 hrs

Tripping

of 220kV

Kaiga-

Kodasalli

and

220kV

Kodasalli-

Nagjheri

line- 1

44/II/3 1. KPCL to check the possibility of

implementing Permissive Over Reach (POR)

with Echo feature at Kodasally end.

2. If the above is not possible, KPCL shall

check the possibility of keeping the 220kV

Kodasalli-Nagjheri lines OPEN at Kodasalli

end and idle-charged at Nagjheri end, and

implement the same.

KPCL Mail received on 07.07.2015:

The matter had been discussed with KPTCL. KPTCL

recommended to keep Zone-2 time lever to zero. If this is

acceptable, then the same shall be incorporated immediately.

Pending

Annexure- III

6 / 20

45/II/13 Tripping

of

400/220k

V ICT-2

Raichur

TPS

30-05-2015at

21:59 hrs

ICT-2 tripped due to

operation of group-2

master trip relay.

KPCL to wire/ connect a spare contact of static

relay to DR unit to capture operation of Group-

2 master trip relay as a temporary arrangement.

KPCL Yet to be informed Pending

45/III/12 Tripping

of 400kV

Raichur-

BTPS line

01-06-2015

at 01:02 hrs

line tripped on R-phase

to earth fault. Line did

not auto-reclose

KPCL to make A/R operational on 400 kV

RTPS – BTPS S/C line at both ends.

KPCL Yet to be informed Pending

Tamil Nadu

44/I/3

(GD)

Outage of

Tiruvalam

substation

24-05-2015

at 19:13 hrs

Failure of Y-phase CT 1. TANTRANSCO to remove the intentional

time delay of 200ms given for STUB protection

as

it is an instantaneous protection.

2. TANTRANSCO to carry out Dissolved Gas

Analysis (DGA) to monitor the healthiness of

all CT’s of similar make.

3. TANTRANSCO to submit the CT failure

report to CEA with a copy to SRPC.

TANTRA

NSCO

TANTRANSCO vide their mail dated 24.06.15 informed that Oil

samples collected and test results awaited. CT failure report sent to

CEA on 20.06.2015.

Mail received on 14.07.2015:

1. STUB protection settings will be revised to 2 In / Inst.

2. DGA test conducted in similar make CTs and the test results are

found normal. (Completed).

3. Completed.


1. STUB protection settings will be revised to 2 In / Inst.

2. DGA test conducted in similar make CTs and the test results are

found normal.

Line-2 tripped on R-

phase to earth fault.

Line autoreclosed at

SVChatram end and

failed to reclose at

Alamathy end. Bphase

to earth fault in line-1.

Line tried for A/r but

due to permanent fault

line did not reclose. ICT

tripped on operation of

over flux protection.

29-03-2015

at

15:29 hrs

Tripping

of 400kV

Alamathy-

SVChatra

m line-

1&2

and

400/230k

V ICT

at

S.V.Chatr

am

43/II/5 TANTRANSCO was requested to swap the

relays between two stations, so that

Main-1 and Main-2 will be of different make at

each station.

TANTRA

NSCO

TANTRANSCO vide their mail dated 24.06.15 informed that

different relays in Main-I & Main-II would be ensured at the

earliest.


Different relays in Main-I & Main-II will be ensured.

Pending

Pending

Annexure- III

7 / 20

Mail received on dated 24.06.15:

2. Zero sequence compensation enabled in the relay on 19.06.2015.

(Completed)

Mail received on dated 14.07.15:

1.No other Feeder / ICT trippings recorded at the time of tripping

of ICT at Thiruvalam.

2. Completed.


No other Feeder / ICT trippings recorded at the time of tripping of

ICT at Thiruvalam. Zero sequence filter enabled in the relay on

19.06.2015.

TANTRA

NSCO

1. TANTRANSCO to take up with OEM for

ensuring stability of the differential relay for

thorough fault and other non-transformer fault

conditions.

2. TANTRANSCO to enable zero sequence

compensation for both the ICTs to avoid

tripping for through fault condition.

ICT-1 tripped on

operation

of differential

protection.

17-04-2015

at

20:15 hrs

Tripping

of

400/230k

V ICT-1

at

Tiruvalam

Substation

44/II/1 Pending

Kerala220 kV breaker of unit-

3 at Idukki Power

house flashed and bus

differential protection

acted. All Generators

(6Nos.) along with all

220 kV feeders tripped

during the incident.

28-04-2015

at 12:30 Hrs

Complete

outage of

Idukki

Hydro

Power

Station

(GD-1)

44/I/1

(GD)

Pending

As per FIR, failure of R-

phase CT of 230kV

Alamathy-Manali feeder

occurred at Alamathy

end. Hence 230KV Bus

bar protection Zone 1 &

2 Operated at Alamathy

substation. All the

230KV feeders, 230KV

Bus Coupler, ICT-3, 4

& 5 LV breakers got

tripped.

TANTRANSCO to furnish a detailed tripping

report including reasons for delayed clearance

of fault at Almathy.

TANTRA

NSCO

Yet to be informed Pending25-05-2015at

09:08hrs

Multiple

tripping at

400/230k

V

Alamathy

substation

45/II/12


1. Reducing the sensitivity of REF protection of Unit # 4, 5, 6 at

Idukki PH: - Generation wing is planning to purchase new

transformer management relays with low impedance REF

protection. Purchase procedures initiated.

2. The replacement/ repair of faulty breakers are under the

consideration of Generation wing. Breakers will be replaced /

repaired in a phased manner. Unit #3 breaker was replaced with

available breaker from the 220kV IDMD feeder. The 220kV CBs

of unit #2 and unit #3 will be replaced with in two months.

3. No abnormalities were noticed in the PLCC equipment at New

Pallom station. It is kept under observation.

KSEB1. KSEB to reduce sensitivity of REF protection

appropriately at Idukki PH.

2. KSEB to replace/ repair the faulty breaker.

3. KSEB to check the PLCC equipment at New

Pallam and inform the remedial measures taken

to PCSC forum.

Annexure- III

8 / 20

41/II/6 Tripping

of 400kV

Coastal

Energen

(CEPL)---

NTPL line

07-02-2015

at 01:07 hrs

and at

00:08hrs on

08-02-2015


had occurred in Line

during both instants. As

seen from D.R of

Coastal Energen

distance relay sensed

fault in zone-2 and earth

fault protection had

operated.

PGCIL to carry out hot-line washing

regularly as NTPL is in highly polluted

location.

PGCIL Yet to be informed Pending

41/II/8 Tripping

of HVDC

Talcher-

Kolar pole-

2

10-02-2015

at 7:37 hrs

Pole-2 tripped due to

ESOF from Talcher end

PGCIL to test the pumps at Talcher HVDC

during pole shut-down and submit the report

to PCSC forum.


PGCIL34/I/7 HVDC

BHADR

AVATHI

POLE 2

18-07-2014 As reported pole-2

tripped due on 5th

harmonic alarm.

1. Complete analysis of the faults and

rectification/remedial action taken to avert

similar occurrence in the HVDC Back to Back

station shall be submitted.

2. The PCSC forum recommended PGCIL,

SRTS-I take up the issue with WRTS to submit

the report as per IEGC guidelines.

3. SRLDC is also requested to send a letter to

WRLDC to submit the reports to SR also.

4. Based on the SRTS/SRLDC

correspondences, SRPC would take it up with

WR and PGCIL if the issue is not getting

resolved.

PGCIL Reply received during 46th PCSC meeting:

Being pursued with POWERGRID, WR-1

Pending


1. All quadramo relays in Madakkathara is working in good

condition. Replacement of the same with numerical one will be

carried out in a phased manner.

2. The SPS settings were revised after this disturbance and the

revised logic is already forwarded to that office vide reference (2)

above. Copy of the same is attached

KSEB1. KSEB to replace Quadramo relay (static)

with numerical one at Madakkathara station.

2. After finalizing the SPS, KSEB shall share

the details of the revised SPS logic for the

North Kerala system to PCSC forum.

Blackout had occurred

in North kerala i.e.,

Complete outage of

220kV Mylatty, 220kV

Taliparamba, 220kV

Kanhirode, 220kV

Vadakara and Shoranur

substations occurred

due

to tripping of 220kV

Thrissur-Areacode and

220kV Thrissur-

Shoranur feeders.

09-05-2015

at 11:18hrs

Disturban

ce in

North

Kerala

system

(GD-1)

44/I/2

(GD)

Pending

Annexure- III

9 / 20

41/II/16 Tripping

of 400 kV

NEYVEL

I TS 2 -

PUGALU

R

15-02-2015

at 18:38 hrs

Line tripped at pugalur

end due to direct trip

receive

PGCIL to check the protection coupler of

PLCC system at Pugalur end.


41/III/2 Tripping

of 400kV

Udumalpe

t-Palakad

line-1&

400

Udumalpe

t-Arasur

line-2

09-02-2015

at 9:50hrs

PLCC of Udumalpet-

Arasur-2 mal-operated

• PGCIL to furnish remedial measures taken.

• PGCIL to properly tune PLCC panels.


42/II/8 Tripping

of HVDC

Talcher-

Kolar pole-

1

23-02-2015

at 15:37

hrs

Pole 1 of Talcher-Kolar

HVDC

Transmission system

tripped on receipt

of ESOF (Emergency

Switch-off) from

Talcher

PGCIL (SR-II) to submit a report on the reasons

for operation of filter protection at

Talcher, and subsequent receipt of ESOF at

Kolar.


Tripping

of 400kV

Jeypore-

Gazuwaka

line-

1&2 and

tripping

of

HVDC

back to

back pole-

1&2 at

Gazuwaka

23-02-2015

at

13:34 hrs

HVDC pole-1 got

tripped due to failure

of 4 no. power supply

card. HVDC

pole-2 tripped on DC

low voltage trip.

400kV Jeypore-

Gazuwaka line-1&2

tripped due to

operation of Over

voltage

protection at Gazuwaka

end.

PGCIL (SR-II) to submit the report of M/s

ABB’s on preventing supply card failures.

PGCIL Yet to be informed Pending42/II/7

Annexure- III

10 / 20

42/II/13 Tripping

of 400kV

Neelaman

gala-

Mysore

Line-1

02-03-2015

at 23:30

hrs

Line tripped on

operation of over

voltage protection at

Neelamangala end.

PGCIL (SR-II) to check OVR operation at

Nelamangala.


42/II/23 Tripping

of HVDC

Bhadravat

hi Pole-1

18-03-2015

at

13:55 hrs

Pole tripped due to

failure of auxiliary

supply

PGCIL (SR-I) to submit the compliance report

on PSAG-11 recommendations to PCSC

forum.

PGCIL Reply received during 46th PCSC meeting:

Tertiary Transformer charged and auxiliary power for HVDC is

being availed from tertiary widings of ICT.

Pending

43/II/2 PGCIL (SR-II) to check the possibility of

providing re-trip feature in LBB relay.


Pending

230kV Bus-2 at Hosur

(PG) got

tripped as spurious

initiation got

extended to LBB relay

of 230kV

Hosur-Hosur(PG) line

at Hosur(PG)

end due to shorting of

contacts in

lockout relay.

400/230kV ICT-2, ICT-

3, 230kV Hosur-

Vinnamangalam,

230kV Hosur(PG)-

Hosur which were

connected to Bus-2 got

tripped along

with bus coupler

breaker

26-03-2015

at 15:40 hrs

Multiple

tripping

at

400/230k

V

Hosur

substation

of

Powergrid

Reply received during 46th PCSC meeting:

Operation is in-order as per OEM manual (ABB HVDC)

42/II/22 Tripping

of

HVDC

pole-1&2

at

Gazuwaka

and

400kV

400kV

Jeypore

Gajuwaka

line -1

14-03-2015

at

17:12 hrs

HVDC Pole-1 at

Gazuwaka tripped due

to

tripping of filter banks

and Pole-2 tripped

due to operation of

differential protection.

400kV Jeypore-

Gazuwaka line-1

tripped

on over-voltage from

Gazuwaka end.

PGCIL (SR-I) to furnish the reasons for

Converter Transformer differential protection

operation for Pole-2 along with the remedial

measures taken.

PGCIL

Annexure- III

11 / 20

44/I/3

(GD)

HVDC

Talcher-

Kolar pole

1 & 2 at

Kolar

24-05-2015

at 19:18 hrs

Due to valve cooling

problem

PGCIL to check the possibility of providing

manual reset of the valve cooling panels of both

the poles in the control room at Talcher and

Kolar end, and implement the same.


44/I/3

(GD)

765 kV

Raichur-

Sholapur

line 1 &

2 tripped

24-05-2015

at 19:19 hrs

Tripped on Overload. 1. PGCIL to provide the status of healthiness of

SPS contact logic in SRLDC’s SCADA.

2. PGCIL to furnish the details of the

implemented SPS-7 scheme including logic

diagram to PCSC forum.


400kV Vemagiri-

Vijayawada line-1&3,

400kV Vemagiri-

Goutami line-2, 400kV

Vemagiri-Konaseema

line-2 and 400/220kV

ICT-2 at Vemagiri

tripped


Triggering incident

was failure of B-phase

L.A in 400kV

Vijayawada-Vemagiri

line-1 at

Vemagiri end.

25-04-2015

at 10:04

hrs

Multiple

tripping at

Vemagiri

substation

of

APTRAN

SCO

44/II/6 1. PGCIL (SR-I) to enable Auto reclosure

feature at Vijayawada end.

2. PGCIL (SR-I) to check distance relay settings

for Vijayawada – Vemagiri line 3, and

furnish a compliance report to PCSC forum.


43/II/2 PGCIL (SR-II) to check the possibility of

providing re-trip feature in LBB relay.


Tripping

of 400kV

Ramagun

dam-

Hyderaba

d line-3,

400kV

Hyderaba

d-

Malkaram

line-1 and

400kV

Bus-1

at

Hyderaba

d

23-04-2015

at

15:11 hrs

400kV Ramagundam-

Hyderabad line-3 at

ramagundam end only

due to DT receive.

400kV Hyderabad-

Malkaram line-1

tripped at Hyderbad end

only and was

holding from Malkaram

end. 400kV Bus-1 at

Hyderabad due to

operation of bus

bar protection.

PGCIL (SR-I) to check healthiness of PLCC

panels at Hyderabad SS, and repair/ replace

them, if necessary.

PGCIL Yet to be informed Pending44/II/4

230kV Bus-2 at Hosur

(PG) got

tripped as spurious

initiation got

extended to LBB relay

of 230kV

Hosur-Hosur(PG) line

at Hosur(PG)

end due to shorting of

contacts in

lockout relay.

400/230kV ICT-2, ICT-

3, 230kV Hosur-

Vinnamangalam,

230kV Hosur(PG)-

Hosur which were

connected to Bus-2 got

tripped along

with bus coupler

breaker

26-03-2015

at 15:40 hrs

Multiple

tripping

at

400/230k

V

Hosur

substation

of

Powergrid

Annexure- III

12 / 20

44/II/7 Tripping

of 765kV

Kurnool-

Tiruvalam

line-1

and

765kV

Kurnool-

NPS-1

25-04-2015

at

18:10 hrs

REF protection of Line

reactor of

Nellore-1&2 and

Tiruvalam line-1

maloperated

due to DC earth fault

1. PGCIL (SR-I) to submit the action taken

report on the measures suggested by their OEM.

2. PGCIL (SR-I) to check for the availability of

Chatter Disable feature in P141 and

configure it appropriately to block operation of

REF protection on DC fluctuations.


44/II/8 Tripping

of 400kV

Gooty-

NPS line-

2

26-04-2015

at 13:16

hrs

R-phase to earth fault

had occurred in

line. Lines auto-reclosed

at gooty end

and later tripped due to

DT receive from

NPS end.

PGCIL (SR-I) to coordinate STUB protection

settings with the distance protection time

settings at NPS.


45/II/21 Tripping

of

400/220k

V ICT-1

at Gooty

Substation

03-06-2015

at 12:30 hrs

ICT tripped due to mal-

operation of differential

relay

1. PGCIL to follow IS and CEA regulations

while carrying out maintenance work.

2. PGCIL to furnish a report on what caused

the ICT-1 tripping including remedial measures.


400kV Vemagiri-

Vijayawada line-1&3,

400kV Vemagiri-

Goutami line-2, 400kV

Vemagiri-Konaseema

line-2 and 400/220kV

ICT-2 at Vemagiri

tripped


Triggering incident

was failure of B-phase

L.A in 400kV

Vijayawada-Vemagiri

line-1 at

Vemagiri end.

25-04-2015

at 10:04

hrs

Multiple

tripping at

Vemagiri

substation

of

APTRAN

SCO

44/II/6 1. PGCIL (SR-I) to enable Auto reclosure

feature at Vijayawada end.

2. PGCIL (SR-I) to check distance relay settings

for Vijayawada – Vemagiri line 3, and

furnish a compliance report to PCSC forum.


To avoid tripping of transmission lines on

transient faults, PGCIL is recommended to carry

out periodic patrolling of lines, and ensure their

proper maintenance by carrying out jungle/

bushing clearance and trimming of tree

branches within the RoW of transmission lines

as per the SRPC transmission line patrolling

guidelines (available under the menu item "All

Uploads Operation Miscellaneous

Transmission Line Patrolling Protocol /

Guidelines for Southern Region" on SRPC

website).

Lines tripped on

transient fault. Auto

reclose was un-

successful. SR &NEW

grid separated due to

tripping of 765kV lines

03-05-2015

at 4:13 hrs

Tripping

of 765kV

Raichur-

Solapur

line-1&2

45/II/15 PGCIL Yet to be informed Pending

Annexure- III

13 / 20

41/II/10 Tripping

of Hassan-

UPCL

line-2

12-02-2015

at 15:57 hrs

Line tripped due to high

resistance fault in B-

phase. DEF picked up at

hassan end and DT was

sent to UPCL. DEF

protection did not pick

up at UPCL

UPCL to revise their DEF relay settings. UPCL Mail recieved on 28-04-2015: Revised settings issued to

UPCL on 27-04-2015 for implementation.

Mail received on 27-05-2015: Revised settings have to be

implemented by UPCL

Pending

with

UPCL

41/II/12 Tripping

of 400KV

Coastal-

NTPL line

13-02-2015

at 22:54 hrs

Line tripped B-phase to

earth fault and later

tripped on R-Y phase

fault. From Coastal end

D.R, Y & B poles of

breaker opened first and

R-pole appears to be

opened on Pole

discrepancy.

CEPL to check A/R scheme at their end. CEPL Yet to be informed Pending

To avoid tripping due to transient faults, PGCIL

(SR-I) is recommended to carry out periodic

patrolling of lines, and ensure proper

maintenance of transmission lines by carrying

out jungle/ bushing clearance and trimming of

tree branches within the RoW of transmission

lines as per the ‘SRPC transmission line

patrolling guidelines’ (available under the menu

item "All Uploads Operation Miscellaneous

Transmission Line Patrolling Protocol /

Guidelines for Southern Region" on SRPC

website).

DC line fault26-05-2015

at 17.55 hrs

Tripping

of HVDC

Talcher-

Kolar

Pole-2.

45/II/29 PGCIL Yet to be informed Pending

Others37/I/9 Tripping

of

400/220k

V ICT-

1&2 at

UPCL

04-10-2014 ICT-1&2 tripped during

transient fault in R-

phase in 400kV Hassan-

UPCL line-1

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.

UPCL It has been reported by UPCL that, the work of review of relay

coordination and setings for the entire plant is given to M//s

Alstom for entire plant. UPCL has furnished the settings given by

M/s Alstom for verification. Revised settings will be issued this

week for implementation

Mail recieved on 28-04-2015: Revised settings issued to

UPCL on 27-04-2015 for implementation.

Mail received on 27-05-2015: Revised settings have to be

implemented by UPCL

Pending

with

UPCL

Annexure- III

14 / 20

41/IV/2 400kV

Tuticorin

PS-NTPL

line

09-02-2015

at 03:17 hrs

Y-phase to earth fault

had occurred in line.

Line auto reclosed at

Tuticorin PS end and


NTPL end.

NTPL to check A/R scheme at their end. NTPL Yet to be informed Pending

42/II/16 Tripping

of UNIT-

3

& 5 at

Jindal

power

station

08-03-2015

19:41hrs

Units tripped due to

tripping of SUT.

JSWEL to enable DEF feature in the numerical

relay for the 220 kV Jindal – Lingapur lines

at Jindal end.

JSWEL Mail received on 27-05-2015(KPTCL): Settings issued to M/s

Jindal for implementation.

Pending

with

JSWEL.

44/III/4 Tripping

of 400kV

Coastal

(CEPL)-

Tuticorin

pooling

station

20-04-2015

at 12:35 hrs

Line tripped at Coastal

energen end only and

was holding from

TTRNPS

CEPL to furnish a detailed report on this trip

event to PCSC forum.

CEPL Yet to be informed Pending

44/IV/8 Tripping

of 400kV

Hassan-

UPCL

line-2

06-05-2015

at

15:37 hrs

Y-phase to earth fault in

line. Line auto reclosed

at

Hassan end and did not

reclose at UPCL

UPCL to check A/R relay operation at their end. UPCL Yet to be informed Pending

36/II/8 400kV

Raichur-

Muniraba

d line

07-09-2014 B-phase to earth fault

had occurred in line.

Line auto reclosed at

Munirabad end and


Raichur end.

KPTCL:

PD (pole discrepancy) time delay would be

changed.

PGCIL /

KPTCL


Miscellaneous

Annexure- III

15 / 20

38/II/5 400kV

Ramagun

dam-

Hyderaba

d line-4

27-10-2014 Line tripped on

Bphase

to earth fault.

Line did not auto

reclose at Hyderabad

end due to

PLCCmal-operation.

Planned to replace the PLCC system within a

week's time at both the ends during the

shutdown.

NTPC/

PGCIL

Yet to be informed. Pending

Pending

with

UPCL.

39/I/2 Tripping

of

400Kv

Ghanapur-

Mamidipa

lly

line

22-12-14

at 10:52 hrs,

24-12-14 at

11:32

hrs,

24-12-14 at

16:16 hrs

Due to PLCC Mal-

operation at HYD S/S

end, DT received at

MMPLY end and line

got tripped.

PGCIL is requested check up with the

manufacturer to resolve the issue and submit

remedial measures to PCSC forum.

PGCIL/

TSTRAN

SCO

Mail received on 26-05-2015 from TSTRANSCO:

On 27-12-2014 PGCIL requested to arrange services of

OEM(Manufacturer)for identifying the problem. TSTRANSCO

arranged the same on 06-01-2015 and the manufacturer testing and

concluded that the problem in not in the newly erected digital

protection coupler at both ends and the issue is related to relay

panel at Ghanapur. [OEM minutes enclosed]

Pending

37/I/6 Tripping

of 400KV

Hassan-

UPCL

line-2

25-09-2014 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.

1. At UPCL end, unused zones of distance

protection (probably zone 5 to 8) shall be

disabled.

2. At UPCL end, time synchronization

between main-1 and main-2 relays shall be

ensured.

3. UPCL shall ensure time synchronization

with Hassan substation.

4. Reasons for non operation of back up

protection at UPCL for high resistance fault

is to be submitted.

5. Reasons for not sending DT to UPCL by

Hassan end is to be submitted.

6. Settings of UPCL are to be reviewed and

informed to PCSC forum.

UPCL /

KPTCL

It has been reported by UPCL that, the work of review of relay

coordination and setings for the entire plant is given to M//s

Alstom for entire plant. UPCL has furnished the settings given by

M/s Alstom for verification. Revised settings will be issued this

week for implementation.


Revised settings issued to UPCL on 27-04-2015 for

implementation.

Mail received on 27-05-2015 (KPTCL):

Revised settings have to be implemented by UPCL

Annexure- III

16 / 20

Tripping

of 400kV

NTPL-

Tuticorin

pooling

station

13-02-2015

at 23:12 hrs

Line tripped on R-phase

to earth fault at 22:53

hrs. Line auto reclosed

at Tuticorin pooling end

and holding. At 23:12

line tripped on B-phase

to earth fault in zone-2

time.

Tripping

of 400kV

NTPL-

Tuticorin

pooling

station

14-02-2014

at 1:41 hrs


had occurred and line

auto reclosed at 01.09

Hrs and holding from

Tuticorin PS end and

line was and up hand

tripping at 01.44.

1. PED to investigate the cause of non-

operation of ICT’s protection system

(differential protection, back-up protection)

and review the relay settings suitably.

2. PGCIL to check the settings of distance

relay and back-up relays for correctness of

operation.

Bus fault occurred in

110kV bus at

230/110kV Bahoor

substation due to failure

of Y-phase main bus

strain insulator. 220kV

lines connected to

Bahoor (viz., Bahoor-

NLC TPS II and Bahoor

– Pondy) tripped from

remote end on operation

of back up protection.

15-02-2015

at 11:20 hrs

Complete

outage at

220kV

Bahoor

Substation

of

Pondicher

ry (GD-1)

41/I/2 PED/PGC

IL


41/II/13,

41/II/14,

41/II/15



location.

NTPL to review A/R scheme at their end.

PGCIL/N

TPL


On account of R-phase

to earth fault, line

tripped at Hassan end

due to operation of

distance Zone-2 and non-

receipt of

carrier. From D.R of

Talaguppa end it is

observed that fault had

occurred in Yphase.

1. PGCIL and KPTCL to ascertain the reason

for the phase discrepancy in the relay

operation and take suitable remedial measures.

2. KPTCL to check the PLCC operation at

Talaguppa end and submit the report to the

PCSC forum.

PGCIL/

KPTCL

Mail recieved on 28-04-2015: End to end testing of PLCC

has been done and problem in the PLCC is atttended.

Mail received on 27-05-2015 (KPTCL) & 29-07-2015:

End to end testing of PLCC has been done and problem in the

PLCC is atttended. Phase

discripancy in the relay operation is to be checked jointly.

Pending01-01-2015

at

13:38 hrs

Tripping

of 400

kV

TALAGU

PPA

–

HASSAN

line

40/II/3

Annexure- III

17 / 20

Tripping

of 400kV

NTPL-

Tuticorin

pooling

station

14-02-2014

at 6:55 hrs

Line tripped on B-phase

to earth fault. Line did

not reclose at NTPL end

Line tripped at Coastal

end only

due to suspected PLCC

maloperation

and was holding from

Tuticorin PS end.

Running Unit at

Coastal energen also got

tripped

during the event.

PLCC end-to-end testing shall be carried out by

CEPL and Tuticorin PS (PGCIL-SR II) by

06.04.2015.

CEPL/

PGCIL(SR-

II)

Yet to be informed Pending19-02-2015

at

16:37 hrs

Tripping

of 400kV

Coastal-

Tuticorin

PS line

42/II/1

Mail received on 26-05-2015 from TSTRANSCO:

It is found that the main-2 ABB make REL316 type distance

relay was defective and same was replaced with MICOM P444 by

M/s.PGCIL on 23.04-2015. After replacement of main-II, DR can

be extracted from this relay. For EL in to service, some field

winding is pending which is being taken up in this month.

Pending42/II/18 Multiple

tripping at

Raichur

thermal

power

station of

KPCL

09-03-2015

at

06:36 hrs

400kV Raichur TPS-

Raichur(PG) line-

1&2, 400kV Raichur-

Mahboobnagar,

Unit#7 and ICT-2 at

RTPS tripped

during the incident. B

phase to earth

fault had occurred in

400kV Raichur

TPS-Raichur line-1

1. KPCL to review REF setting (DMT or

IDMTL) for unit-7 by first week of April, 2015

and

inform the same to PCSC forum.

2. TSTRANSCO to furnish Mehaboobnagar’s

DR and EL and the reasons for distance relay

operation at their end within a week’s time.

3. PGCIL (SR-I) to rectify the issues relating to

A/R operation, relay reach (Z2), reverse reach

(Z4) and SOTF auxiliary contacts within a

week’s time, and submit the actions taken to

PCSC forum.

KPCL/TS

TRANSC

O/PGCIL

(SR-I)

400kV Raichur(PG)-

Gooty line-2,

400kV Raichur TPS-

Raichur(PG)

line-1&2, 400kV

Raichur-

Mahboobnagar, Unit#5

at RTPS

tripped during the

incident

KPCL, KPTCL and PGCIL (SR-I) to furnish the

action taken report on the

recommendations given by PSAG members held

at Raichur on 22-04-2015 and

23-04-2015.

KPCL/KP

TCL/

PGCIL(SR-

I)

Yet to be informed Pending11-04-2015at

18:04 hrs

Multiple

tripping at

400kV

Raichur(P

G)

and

Raichur

thermal

power

station of

KPCL

43/II/12

41/II/13,

41/II/14,

41/II/15



location.

NTPL to review A/R scheme at their end.

PGCIL/N

TPL


Annexure- III

18 / 20

43/III/1 400kV

Guttur-

Narendra

line-1

11-03-2015

at 17:16 hrs

Line tripped at

Narendra end only

on direct trip receive

and line was holding

from Guttur

End to end testing shall be

conducted on 6.5.2015.

KPTCL/

PGCIL(SR-

II)


End to end testing is yet to be conducted

Pending

Tripping

of Unit 1

at NCTPS

24-05-2015

at 19:13 hrs

ID Fan trip

Tripping

of Unit 1

at MEPL

24-05-2015

at 19:13 hrs

Coal Mill tripped

Tripping

of Unit 1

at

Krishnapa

tnam

24-05-2015

at 19:17 hrs

Generator Protection

operated

Tripping

of Unit-8

at RTPS

24-05-2015

at 19:19 hrs

Tripped on Overvoltage.

1. MEPL to ensure healthiness of all CT’s by

carrying out Tan Delta and DGA tests wherever

necessary.

2. MEPL to take suitable action to correct the

operation of tie-CB Bay Control Unit that

caused LBB/ BBP operation.

3. PGCIL (SR-1) to carry out end-to-end

PLCC testing in coordination with MEPL and

ensure that carrier-aided protection on MEPL –

NPS line is in healthy condition.

4. SEL to properly time-coordinate their Over

Current phase and Earth fault relays in

consultation with MEPL.

Y phase CT failure at

MEPL led to tripping of

400kV NPS-MEPL,

400kV SEPL-MEPL

line and Unit-2 at

MEPL. Uni-1 was not in

service at the time of

tripping

20-05-2015

at 20:38 hrs

Complete

outage of

MEPL

power

station

45/I/2

(GD)

MEPL/

PGCIL(SR-

I)/ SEL


44/I/3

(GD)

1. All Tripped units, viz., Krishnapatinam,

MEPL, Raichur, NCTPS to submit a detailed

report on this event including the remedial

measures taken to PCSC forum.

2. KPCL to check the excitation system of Unit

8 of RTPS, and submit the remedial measures

taken to PCSC forum.

KPCL/

MEPL/

APGENC

O/ TNEB

TANGEDCO vide their mail dated 07.07.2015 informed that as

per the discussion and recommendation of 44th meeting of PCSC

held on 28.05.2015, a time delay of 2 Sec had been introduced for

the above tripping for all the ID fans at NCTPS-II.

Pending

Annexure- III

19 / 20

1. MEPL to ensure healthiness of all CT’s by

carrying out Tan Delta and DGA tests wherever

necessary.

2. MEPL to take suitable action to correct the

operation of tie-CB Bay Control Unit that

caused LBB/ BBP operation.

3. PGCIL (SR-1) to carry out end-to-end

PLCC testing in coordination with MEPL and

ensure that carrier-aided protection on MEPL –

NPS line is in healthy condition.

4. SEL to properly time-coordinate their Over

Current phase and Earth fault relays in

consultation with MEPL.

Y phase CT failure at

MEPL led to tripping of

400kV NPS-MEPL,

400kV SEPL-MEPL

line and Unit-2 at

MEPL. Uni-1 was not in

service at the time of

tripping

20-05-2015

at 20:38 hrs

Complete

outage of

MEPL

power

station

45/I/2

(GD)

MEPL/

PGCIL(SR-

I)/ SEL


Annexure- III

20 / 20

Sl.No. Element NameOutage

date/time

Revival

date/time

Reason for

OutageSender/ Receiver

Remedial Measures/ Actions

taken

1 220 kV AMBEWADI - PONDA 123-06-

2015/11:39:00

EARTH

FAULT

RELAY

OPERATED

KPTCL/ GOA To-be-discussed

2400 kV KHAMMAM - KALPAKKA

1

13-07-

2015/12:12:00

13-07-

2015/12:22:00Y - N FAULT PGCIL(SR-I)/ APTRANSCO

APTRANSCO: Auto reclose

attempted and successful for Y-

N, Zone-1 momentary fault.

Hence Line is in service from

Kalpaka End.

PGCIL(SR-II):

3 400 Kv NAGAPATNAM-TIRCHY14-07-

2015/10:57:00

14-07-

2015/11:01:00

DT

RECEIVED

AT TRICHY

PGCIL(SR-II) To-be-discussed

4 220 Kv CHIKKODI - MUDUSHINGI17-07-

2015/05:01:00

17-07-

2015/05:33:00

TRANSIENT

FAULTKPTCL To-be-discussed

5 400 kV GAJWEL - HYDERABAD18-07-

2015/02:16:00

18-07-

2015/03:28:00

MALOPERAT

ION OF

REACTOR

PROTN

TSTRANSCO/ PGCIL(SR-I) To-be-discussed

Pending Remedial Measures/ Actions taken

for the Critical Tripping Incidents (as on 01.09.2015)

Annexure-IV

1

6400 Kv KRISHNAPATNAM -

NELLORE

20-07-

2015/11:27:00

20-07-

2015/12:00:00

BUS -1

TRIPPED :

REASON

AWAITED

APGENCO/ APTRANSCO

APGENCO: BUS-1 was tripped

at Power Grid Sub-

Station(PGCIL), Nellore during

the operation of the Isolators,

which is not pertaining to

APGENCO.

APTRANSCO: Line tripped at

Krishnapatnam end only.Line is

in service from Nellore-AP.

PGCIL (SR-I):

7 220 Kv CHIKKODI - TALANDGE21-07-

2015/17:15:00

21-07-

2015/20:16:00

R-PHASE TO

GROUND

FAULT

KPTCL To-be-discussed

8 400/220 kV ICT-5 AT RSTPS22-07-

2015/01:30:00

PRD

OPERATEDNTPC To-be-discussed

9 220 kV SEDAM - TANDUR23-07-

2015/11:30:00

23-07-

2015/12:11:00

EARTH

FAULTKPTCL/ TSTRANSCO To-be-discussed

10 400 Kv PUGALUR - KARAIKUDI 223-07-

2015/18:40:00

23-07-

2015/19:30:00

TRIPPED ON

B-PH FAULTPGCIL(SR-II) To-be-discussed

11400 Kv KAYATHAR - KARAIKUDI

1

26-07-

2015/18:26:00

26-07-

2015/19:31:00Y - N FAULT

TANTRANSCO/ PGCIL(SR-

II)

TANTRANSCO: Temporary

fault. Feeder normalised at

19:33 hrs. Voltage continuously

observed in D.R at Kayathar

was due to the presence of Line

Reactor.

12 400 kV VIJAYAWADA - VTPS IV 126-07-

2015/00:05:00

TRIPPED

DUE TO B-

PHASE CT

BLAST

PGCIL(SR-I)/ APGENCO

APGENCO: This issue pertains

to PGCIL.

PGCIL(SR-I):

Annexure-IV

2

13 400 Kv KLVDPT - VALLUR 227-07-

2015/16:56:00

27-07-

2015/18:00:00Y - N FAULT PGCIL (SR-II)/ NTECL

NTECL: Kalivanthapattu Line 2

Y phase tripped on Y phase

earth fault at

16:56:15:688 hrs. Line got auto-

reclosed succesfully at

16:56:16:711 hrs. Then, the

line tripped again on Y to B

phase fault at 16:56:19:516.

The fault occurred due to arcing

in the newly replaced composite

long rod polymer insulator in

PGCIL tower during strong

wind. No remedial action

required at NTECL end.

14 400 Kv HASSAN - UPCL 128-07-

2015/15:35:00

28-07-

2015/16:05:00

DPR

OPERATEDPGCIL (SR-II)/ UPCL To-be-discussed

15400 kV UDUMALPET -

TIRUNELVELI 2

28-07-

2015/16:48:00

28-07-

2015/17:10:00B-N FAULT PGCIL (SR-II) To-be-discussed

16400 kV HASSAN -

NEELAMANGALA 1

29-07-

2015/19:09:00B-N FAULT PGCIL (SR-II)/ KPTCL To-be-discussed

17 400 kV GUTTUR - HIRIYUR 129-07-

2015/11:08:00

29-07-

2015/11:33:00

DT

RECEIVED

AT HYR END

KPTCL/ PGCIL (SR-II) To-be-discussed

18 400 kV KHAMMAM - KTPS 230-07-

2015/06:08:00

30-07-

2015/06:58:00

TRIPPED ON

B-PH FAULTPGCIL (SR-I)/ APGENCO To-be-discussed

19 400 kV KAIGA - NARENDRA 230-07-

2015/03:50:00

30-07-

2015/04:41:00

TRIPPED

WHILE GT

ISOLATION

AT KAIGA

END

KAPS/ PGCIL(SR-II) To-be-discussed

Annexure-IV

3

20 400 Kv HASSAN - UPCL 201-08-

2015/09:18:00

01-08-

2015/10:02:00Y-N FAULT PGCIL (SR-II)/ UPCL To-be-discussed

21 400 Kv HASSAN - UPCL 201-08-

2015/15:20:00

01-08-

2015/15:41:00

TRIPPED ON

B-PH FAULTPGCIL (SR-II)/ UPCL To-be-discussed

22 400 Kv HASSAN - UPCL 201-08-

2015/22:32:00

01-08-

2015/23:13:00

DISTANCE

PROTECTIO

N

OPERATED

PGCIL (SR-II)/ UPCL To-be-discussed

23 GOOTY-NELAMANGALA02-08-

2015/09:18:00

02-08-

2015/10:57:00

TRIPPED AT

SHOLAPUR

END ONLY.



2015/13:20:00

02-08-

2015/18:48:00

TRIPPED ON

B-PH FAULTKPTCL/ GOA To-be-discussed

25 HVDC BHADRAVATHI POLE 203-08-

2015/02:01:00

BLOCKED

DUE TO VCC-

2 MAIN CKT

FULL FLOW

VERY LOW

PGCIL (SR- I) To-be-discussed

26 400 Kv COASTAL - NTPL03-08-

2015/15:43:00

03-08-

2015/16:11:00R - N FAULT CEPL/ NTPL To-be-discussed

27400/220 kV ICT-2 AT

VISAKHAPATNAM

04-08-

2015/12:49:00

04-08-

2015/13:31:00

DUE TO BUS

BAR

PROTECTIO

N ACTED ON

220KV SIDE


Annexure-IV

4

28 400/220 kV ICT-1 AT KAIGA04-08-

2015/21:56:00

Y-PH LA

FAILUREKAPS To-be-discussed

29 HVDC BHADRAVATHI POLE 105-08-

2015/10:53:00

05-08-

2015/11:23:00

AUX.

SUPPLY

FAILURE


30 400/220 kV ICT-2 AT RAICHUR06-08-

2015/04:52:00

REASON

AWAITEDKPTCL To-be-discussed

31 400 kV KAIGA - GUTTUR 107-08-

2015/11:19:00

07-08-

2015/12:33:00

DISTANCE

PROTECTIO

N

KAPS/ KPTCL To-be-discussed


2015/10:51:00

08-08-

2015/11:19:00

DISTANCE

PROTECTIO

N



2015/11:15:00

09-08-

2015/11:37:00R G FAULT KPTCL/ GOA To-be-discussed


2015/09:27:00

13-08-

2015/10:10:00B - N FAULT KAPS / KPTCL To-be-discussed

35400 Kv VIJAYAWADA - NELLORE

- AP - 3

15-08-

2015/14:04:00

15-08-

2015/14:52:00B-N FAULT PGCIL (SR-I) / APTRANSCO To-be-discussed

36400 Kv VIJAYAWADA - NELLORE

- AP - 3

15-08-

2015/15:40:00

15-08-

2015/20:40:00B-N FAULT PGCIL (SR-I) / APTRANSCO To-be-discussed

37 220 kV SABARGIRI - THENI16-08-

2015/12:15:00

16-08-

2015/12:45:00

SINGLE

PHASE

FAULT

KSEB / TNEB To-be-discussed

38 400 Kv NCTPS - SVCTM-II16-08-

2015/00:46:00

TRIPPED ON

B-N FAULTTNEB To-be-discussed

Annexure-IV

5

39 220 kV SABARGIRI - THENI17-08-

2015/10:02:00

17-08-

2015/15:42:00Y-N FAULT KSEB / TNEB To-be-discussed

40220 kV YERANDAHALLY -

HOSUR

17-08-

2015/12:50:00B-N FAULT KPTCL / TNEB To-be-discussed


2015/13:20:00

17-08-

2015/15:28:00

DECLARED

FAULTYKPTCL / GOA To-be-discussed

42220 kV KUNDRA -

KAYAMKULAM

18-08-

2015/16:32:00

TRIPPED ON

Y-PH FAULTKSEB / NTPC To-be-discussed

43400 Kv SATTENAPALLI -

SRISAILAM 2

18-08-

2015/15:25:00

BUS BAR

ACTED ON B-

PH FAULT

APTRANSCO / TSGENCO To-be-discussed

44400 kV SRISAILAM-

MAMIDIPALLI 2

18-08-

2015/15:25:00

BUS BAR

ACTED ON B-

PH FAULT

TSGENCO / TSTRANSCO To-be-discussed

45 220 kV EDAMON - EDAPPON18-08-

2015/16:32:00

18-08-

2015/17:01:00

TRIPPED ON

Y-PH FAULTKSEB To-be-discussed

46 765 KV KURNOOL - NPS 119-08-

2015/13:43:00

19-08-

2015/15:45:00

TRIPPED

DUE TO

LINE

REACTOR W

T I HIGH

PGCIL (SR-I) To-be-discussed

47 400 Kv BTPS - YTPS20-08-

2015/00:14:00

20-08-

2015/01:05:00

RELAY MAL

OPERATIONKPCL To-be-discussed


2015/10:28:00

21-08-

2015/11:06:00B - N FAULT KAPS/ KPTCL To-be-discussed

Annexure-IV

6


2015/12:32:00

21-08-



2015/13:00:00

21-08-

2015/13:10:00B - N FAULT KPTCL/ GOA To-be-discussed


2015/15:02:00

22-08-

2015/15:58:00B-N FAULT KAPS/ KPTCL To-be-discussed

52 400 kV GUTTUR - HIRIYUR 123-08-

2015/10:01:00

23-08-

2015/13:12:00

BUS BAR

CONNECTIO

N

KPTCL/ PGCIL(SR-II) To-be-discussed


2015/11:35:00

25-08-



2015/12:37:00

25-08-


55 400 kV NEYVELI TS 2 - PUGALUR25-08-

2015/16:09:00

25-08-

2015/17:50:00

TRIPPED

DUE TO

ARCHING

ON BUS-1

ISOLATOR

AT NLC

NLC/ PGCIL(SR-II) To-be-discussed

56 220 Kv CHIKKODI - MUDUSHINGI26-08-

2015/10:15:00

26-08-

2015/14:19:00

DISTANCE

PROTECTIO

N ACTED


57400 kV SRISAILAM-

MAMIDIPALLI 2

26-08-

2015/15:40:00

26-08-

2015/18:40:00JUMPER CUT TSGENCO/ TSTRANSCO To-be-discussed

Annexure-IV

7

58 400/110 kV ICT-4 AT S'PUDUR26-08-

2015/15:26:00

26-08-

2015/18:18:00

TRIPPED

DUE TO

BREAKER

OIL

LEAKAGE

TNEB To-be-discussed


2015/21:44:00

EARTH

FAULTKPTCL/ GOA To-be-discussed


2015/15:17:00

28-08-



2015/15:54:00

29-08-

2015/16:30:00

DISTANCE

PROTECTIO

N


62 400/230 kV ICT-2 AT SALEM30-08-

2015/03:49:00

30-08-

2015/04:34:00

BUS BAR

ACTED ON

220KV SIDE

DUE TO CT

BLAST

PGCIL (SR-II) To-be-discussed

63 400/230 kV ICT-1 AT SALEM30-08-

2015/03:49:00

30-08-

2015/04:18:00

BUS BAR

ACTED ON

220KV SIDE

DUE TO CT

BLAST

TNEB To-be-discussed

Annexure-IV

8

of 1

Annexure-V (Zone-3 philosophy)

The general philosophy to be followed for Zone-3 settings in SR had been discussed in the Sub

Group meeting of PCSC held on 20-11-2013 and finalized during PCSC-26 held on 21.11.2013.

These are as given below:

1. Load encroachment feature would be enabled on all 400 kV lines and also on 220/230 KV lines

where Numerical relays are installed.

2. Load angle shall be kept below 30 degree and if possible it should be set at 26 degree. Resistive

reach of the relay should be more than sum of line resistance, Arc resistance and Tower foot

resistance.

3. Resistive reach of the relay should be less than minimum load resistance of the system ideally, and if

possible should be kept at 60% of minimum Load resistance. This percentage is only an indicative

figure, places where high resistance fault have occurred should analysis previous fault data for setting

resistive reach.

4. Out of Step Settings to be enabled in Critical lines after due analysis of PMU data.

5. Timing for Zone-3 action is as follows:

a. 400 kV lines – 1 sec.

b. Interstate lines – 1 sec

c. For Zone 4/5/Rev Zone : Zone 3 time + 100 msec

------------------------------------------------------------------------------------------------------------------------------------ Order in Petition Nos. 86/MP/2014 and 374/MP/2014 Page 1 of 18

CENTRAL ELECTRICITY REGULATORY COMMISSION NEW DELHI

Coram: Shri Gireesh B. Pradhan, Chairperson

Shri A.K Singhal, Member Shri A.S.Bakshi, Member

Date of Order : 18.8.2015

Petition No. 86/MP/2014 In the matter of

Petition under Section 94 (f) of the Electricity Act, 2003 seeking time extension for implementing the Commission‟s order dated 20.2.2014 in Petition No. 146/MP/2013 with I.A. 36/2013, in the matter of providing protection systems having reliability, selectivity, speed and sensitivity and keeping them functional in terms of Regulation 5.2 (i) of the Central Electricity Regulatory Commission (Indian Electricity Grid Code) (First Amendment) Regulations, 2012 read along with Regulation 3 (e) of Central Electricity Authority (Grid Standards) Regulations, 2010 and following best practice of O&M of transmission elements for ensuring security of the Southern Regional grid as well as the inter-connected Indian grid.

And In the matter of Kerala State Electricity Board Limited Vyduthi Bhavanam, Pattom, Thiruvananthapuram-695 004 ….. Petitioner

Vs.

1. Southern Regional Load Despatch Centre 29, Race Course Cross Road, Bangalore-110 016. 2. Southern Regional Power Committee 29, Race Course Cross Road, Bangalore-110 016 ....Respondents

Annexure- VI

1 / 18


Petition No. 374/MP/2014

In the matter of

Petition under Section 94 (f) of the Electricity Act, 2003 seeking extension of time in implementing the Commission‟s order dated 20.2.2014 in Petition No. 146/MP/2013 and I.A. 36/2013 of SRLDC for providing protection systems having reliability, selectivity, speed and sensitivity and keeping them functional in terms of Regulation 5.2 (i) of the Central Electricity Regulatory Commission (Indian Electricity Grid Code) (First Amendment),Regulations, 2012 read along with Regulation 3 (e) of Central Electricity Authority (Grid Standards) Regulations, 2010 and following best practices of O&M of transmission elements for ensuring security of the Southern Regional grid as well as the interconnected Indian Grid. And In the matter of Tamil Nadu Transmission Corporation Limited (TANTRANSCO) Protection and Communication, 1st Floor, 5B Block, 144, Anna Salai, Chennai-600 002 Petitioner Vs

Southern Regional Load Despatch Centre 29, Race Course Cross Road, Bangalore-110 016. Respondent Following were present: Shri George V.James, KSEB Shri S. Vallinayagam, Advocate, TANTRANSCO Shri J. Rexline Terse, TANTRANSCO Shri V.Suresh, SRLDC Ms. Jyoti Prasad, POSOCO Ms. Abilla Zaidi, POSOCO Ms. Jayantika Singh, SRPC and SRLDC

ORDER The petitioners, Kerala State Electricity Board Limited and Tamil Nadu

Transmission Corporation Limited, have filed the present petitions for seeking

Annexure- VI

2 / 18


extension of time to comply with the Commission`s direction dated 20.2.2014 in

Petition No. 146/MP/2013.

Background of the case:

2. As per the recommendations in Enquiry Committee report, a third party

protection audit in Southern Region was carried out and all constituents of Southern

Region (SR) agreed in-principle for implementation of the recommendations of the

Committee. Since a number of recommended items were not implemented by the

constituents of Southern Region, Southern Regional Load Despatch filed Petition No.

146/MP/2013 seeking directions to the constituents of SR to ensure timely

implementation of recommendations of Protection Audit. The Commission, after

hearing all the constituents of SR and SRLDC, by order dated 20.2.2014 issued the

following directions:

“27. We agree to the petitioner's contention that the linking implementation of protection audit/PCC recommendations with funding modality has resulted into implementing schedule becoming uncertain which is undesirable as the matter involves grid security. The petitioner has proposed to segregate the works of implementation in two Phases, namely Phase-I requiring immediate attention and Phase-II requiring timely implementation. Phase-I involves minor works such as revision of settings, replacement of numerical relays, implementation of bus-bar protection in critical 220 kV sub-stations etc. and Phase-II involves activities such as replacement of old breakers etc. which may require some time. Accordingly, we direct the respondents to implement the works as mentioned in Phase-I and Phase-II by 1.5.2014 and 1.9.2014 respectively. SRPC is directed to coordinate the protection setting issue and submit a report regarding implementation of Phase-I activities by 1.6.2014. SRPC is further directed to submit bimonthly status report for works mentioned in Phase-II to the Commission.

29. The petitioner has submitted that number of respondents are not complying with the provisions of Regulation 5.2 (r) of the Grid Code and the directions of the Commission. We administer a strong warning to the respondents to take all possible measures permissible under the Act and the Grid Code to provide

Annexure- VI

3 / 18


data /information to RLDC and RPC for maintaining reliability and security of the grid. We also make it clear that failure in this regard will amount to non-compliance of the directions of this Commission and render the constituent liable for proceedings under Section 142 of the Electricity Act, 2003 and other relevant provisions. We also direct the petitioner and SRPC to coordinate and monitor the progress and compliance of Commission's directions and ensure compliance of Regulations 5.2 (r) of the Grid Code and report instances of non-compliance to the Commission.”

Petition No. 86/MP/2014 filed by Kerala State Electricity Board Limited

3. Kerala State Electricity Board Limited (KSEBL) has filed this petition for seeking

extension of time for implementation of the Commission‟s order dated 20.2.2014 in

Petition No. 146/MP/2013. KSEBL has submitted that it is working under the

Government of Kerala and all major works, procurement, etc. are governed and

guided by the rules and regulations of Government of Kerala.

4. KSEBL has submitted that it has to comply with all the tender formalities such

as administrative sanction for procurement/work, finalization of the specifications,

inviting tenders with wide publicity, evaluation of technical tender documents, review

of pre-qualification committees, financial bid evaluation, issue of LOI, etc. The said

formalities require a minimum of six months before issuing purchase order for a

particular item. If the same is re-tendered, additional period of four months also would

be required for the whole process. In case of 220 kV Pothencode sub-station, certain

works in Phase-II can only be completed with double bus arrangement which is

included in Phase-I. KSEBL has submitted the status of phase-wise details of

protection audit remarks, action taken so far and proposed road map with time line for

implementation of remaining protection audit remarks works along with PERT chart.

Annexure- VI

4 / 18


5. In view of the above, KSEBL has made the following prayers:

“Considering the above submissions made by KSEB Ltd. and the difficulties faced by

KSEB Ltd. regarding the timely implementation of the Hon`ble CERC order dated 19.12.2013, in the matter of completion of Phase-I & II works of Protection Audit, it is prayed before the Hon`ble Commission that

(a) Time extension may kindly be granted for Phase-I works till 31.12.2014 and 220 kV

Pothencode sub-station date of completion of phase-I works by 31.3.2015.

(b) Time extension may kindly be granted for Phase-II works till 31.5.2016.”

6. The matter was heard on 15.7.2014. During the course of the hearing, the

representative of KSEBL submitted that Phase-I requires minor works to be completed

such as revision of settings, replacement of numerical relays, implementation of bus

bar protection in critical 220 kV sub-stations, etc. and phase-II involves activities such

as procurement of circuit breakers and current transformers. The representative of

KSEBL further submitted that certain sub-stations of KSEBL are very old and require

different equipment. At certain sub-stations, there are space constraints. The

representative of KSEBL submitted that considering all these limitations, KSEBL is

seeking time for implementation of works in Phase-I and Phase-II of the Protection

Audit till 31.12.2014 and 31.5.2016 respectively and for completion of Phase-I works

of 220 kV Pothencode sub-station till 31.3.2015.

7. The Commission directed Southern Regional Load Despatch Centre (SRLDC)

to file (i) reasonableness of time sought by KSEBL for Phase-II, (ii) position of other

constituents in regard to implementation of the Commission`s order dated 20.2.2014

in Petition No. 146/MP/2013 and (iii) status report regarding visibility of protection

system of Southern Region constituents in the SCADA system of SLDC.

Annexure- VI

5 / 18


8. SRLDC, vide its affidavit dated 1.9.2014, has submitted as under:

(a) As far as time scale for attending protection audit remarks is concerned,

the maximum time required for any item which requires procurement action

would be about 10 months as under:

Activity Months

Finalization of Specification 0.5

Estimate preparation 0.5

Initiating proposal 0.5

Approval of Proposal 1

Calling tender 0.5

Processing Tenders 2

Discussion &Issue of LoA 1

Supply of Materials 3

Erection,Testing &Commissioning 1

Total Period 10

(b) For CT/CVT circuit breakers, the supply and erection period may be 8 to

10 months in place of 3 to 4 months shown in table above. Thus, maximum time

schedule for any item even if it is commenced only now, shall be 15 to 16 months.

During the special meeting on 19.8.2014, SRPC also opined that time scale

computed above is practical and reasonable.

(c) The rational time schedule of individual milestone for implementation of

all the recommendations could be as under:

S.No Major Milestone Description Practically possible time schedule

1 Technical and Administrative approval including finalization, finance concurrence, start-up of tendering process.

2 to 3 months for all the items as multiple proposals are to be processed

2 Tendering process including calling of tenders, pre/post bid

3 to 4 months for all the items as multiple proposals are to be

Annexure- VI

6 / 18


discussion, placement of LOA processed

3 Supply of materials including FAT etc.

8 to 10 months for items like CT,CVT, Breaker etc., while about 3 months for other items

4 Installation, testing and commissioning including SAT, etc.

3 to 4 months for all the items as the construction activities like foundation, structural erection etc,. could be done as a parallel activity during supply period.

5 Total implementation period 3 months for items that involves relays/meter and minor procurement.

12 months for items that involve major procurement, design changes with major site modification/civil activities.

(d) According to KSEBL, works such as arrangement for earth resistance

measurement, etc. mentioned at Iddukki HEP would be done as a part of

Renovation and Modernization (R & M). In the 220/230 kV sub-stations, major

changes and multiple works are required for implementation of the

recommendations of protection audit due to space constraints in the very hilly

terrain old sub-station. Iddukki HEP is critical generating station of KSEBL and

number of times partial grid disturbances had occurred in the generating station.

The works at Idukki HEP requires special attention of KSEBL and shall not be

treated as regular R&M works. Considering the same, KSEBL is required to make

all possible efforts to complete the entire work recommended at Iddukki HEP by

December 2015/March 2016.

(e) During deliberation at SRPC on 19.8.2014, KSEBL confirmed that „it would be

completing all the Phase-I items by December 2014, Bus-bar protection works

identified for Kanaiyampetta sub-station by March 2015 and all other items of the

Annexure- VI

7 / 18


Phase-II activities by December 2015 except at Iddukki HEP, which is clubbed with

R&M proposal,. This appears practically reasonable considering the fact that

actions were effectively commenced by KSEBL in the recent past. However, the

R&M proposals need to be expedited‟.

9. Neyveli Lignite Corporate Limited (NLC), which is not a party in the present

petition, vide its affidavit dated 11.9.2014 has filed status of implementation of

protection audit remarks. NLC has further submitted that during the hearing of the

petition, the Commission, vide RoP dated 15.7.2014, directed SRLDC to file the status

of the constituents of Southern Region in regard to the implementation of the

Commission‟s order dated 20.2.2014. Accordingly, SRPC requested the constituents

of Southern Region to submit affidavit directly to the Commission as per the decision

of the Protection Coordination Sub-Committee (PCSC) meeting held on 31.7.2014.

NLC has submitted that based on the direction of SRPC, it has filed the present

affidavit containing the status of compliance of the recommendations of protection

audit with respect to NLC generating stations. NLC has submitted that SRPC has

issued 25 guidelines for NLC generating stations. Out of these, 7 guidelines are to be

completed in Phase-I and the remaining 18 are to be completed in Phase-II. NLC has

stated that 22 guidelines are complied with and only 3 guidelines, namely replacement

of existing micro mho distant protection (main-I) relays in TPS-I expansion with

numerical relay (Phase-I), providing 2nd bank of 48 V battery for PLCC in TPS-I

Expansion and TPS-II Expansion (Phase-II) are to be complied with by NLC which

would be completed by 31.12.2014 and 31.3.2015 respectively.

Annexure- VI

8 / 18


Petition No. 374/MP/2014 filed by Tamil Nadu Transmission Corporation Limited (TANTRANSCO) 10. Tamil Nadu Transmission Corporation Limited has filed this petition for seeking

extension of time for implementation of remarks of protection audit. TANTRASCO has

submitted as under:

(a) Protection Audit for the 33 nos. of sub-stations of TANTRANSCO has

been completed. Minor issues recommended by the Audit Team under Phase- I

and Phase-II activities have been resolved and in this regard, report and

pending activities with regard to Phase-I and Phase-II works have already been

submitted to SRPC. Procurement action for materials is being carried out in

phased manner which involves a minimum time frame of 6 months for

processing the tender.

(b) All possible steps are being taken by TANTRANSCO, namely purchase

orders have been placed for supply of distance relays for feeder protection,

differential relays for auto transformer protection and carrier sets with coupler

for providing carrier inter-trip and redundant channels to comply with the

directions of the Commission. However, despite sincere efforts made by

TANTRANSCO, the works of Phase- I and Phase- II activities could not be

completed within the prescribed time specified in the order dated 20.2.2014 in

146/MP/2013.

Annexure- VI

9 / 18


(c) As per the recommendations of SRPC, different make of relays for Main

1 and Main 2 protection as well as separate DC source for different protection

schemes are being adopted in the new sub-stations to ensure grid security.

The new stations are equipped with sub-station Automation System which

involves GPS, Disturbance Recorder and Event Logger.

(d) In the existing generating stations, for synchronization of all relays with

GPS could be enabled only after replacing the static relays with numerical

relays. This process involves procurement of new relays and replacing them in

place of old ones.

(e) Provision of bus section breaker for sectionalizing the bus to avert total

sub-station outage involves procurement of breaker, erection and modification

of bus bar Protection Scheme and the requirement is covered in DPR. This

process involves space constraints in some places, bay shifting works and

procurement through tender which requires considerable time.

(f) The existing protection scheme in TANTRANSCO ensures stable

operation. TANTRANSCO is taking all steps to prevent/minimize system

outage. During July 2014 to February 2015, total 583 trippings have occurred in

Southern Region. Out of this, 28 trippings occurred in TANTRANSCO which is

4.80% of total trippings in Southern Region. From this, it is evident that the

trippings are not due to failure of protection schemes. Trippings are always

reviewed by SRLDC and SRPC. The recommendations of Protection Co-

Annexure- VI

10 / 18


ordination Sub-Committee of SRPC are being complied with by

TANTRANSCO.

11. In view of the above, TANTRANSCO has made the following prayers:

“(a) Time extension upto 31.3.2015 for completing the Phase-I activities of providing numerical relays for feeder protection and auto transformer protection;

(b) Time extension upto 30.6.2016 for other Phase-I activities such as provision of line VT, 5 core CT, Time synchronizing with GPS, DR and EL and Phase-II activities;

(c) Time extension upto 30.6.2017 for Renovation & Modernization of Singarpet, Singaperumalkoil and Tondiarpoet 230 KV Substations; and (d) Such other order or orders as this Hon`ble Commission may deem fit and proper in the facts and circumstances of the case.”

12. The matter was heard on 15.1.2015. During the course of hearing, learned

counsel for TANTRANSCO submitted that due to financial and time constraints,

TANTRANSCO could not implement the recommendations of protection audit.

Learned counsel further submitted that there are 6 to 7, 230 kV sub-stations which are

very old and require additional land and entire civil work has to be done for installation

of new equipment. The representative of SRPC and SRLDC submitted that SRPC and

SRLDC convened a meeting of all the constituents of Southern Region wherein

detailed inputs were given to each constituent regarding improvement of the State

system. The representative of SRLDC submitted that SRPC and SRLDC have made

efforts on their own to take feedback on the status of implementation from the

individual constituents of the Southern Region. The Commission directed the other

constituents of the Southern Region to submit the status of implementation of

protection system in their respective States.

Annexure- VI

11 / 18


13. TANTRANSCO, vide its affidavit dated 28.3.2015, has submitted that in

compliance with the Commission`s directions, purchase orders have already been

placed for supply of distance relays for feeder protection, differential relays for auto

transformer protection and carriers sets with coupler for providing carrier inter-trip and

redundant channels. TANTRANSCO has further submitted that availing „Line Clear‟ is

one of the major difficulties due to operational constraints. TANTRANSCO has

submitted the details of remedial measures for the trippings in its affidavit dated

28.3.2015.

14. Karnataka Power Transmission Corporation Limited (KPTCL) vide its affidavit

dated 31.3.2015 has submitted that all the constituents of Southern Region were

directed vide order dated 20.2.2014 to complete the implementation of activities

covered under Phase-I and Phase-II of protection audit observations by 1.5.2014 and

1.9.2014 respectively. Since implementation of Phase-I and Phase-II works involve

tendering, procurement and execution of works based on availability of shutdowns,

the Commission`s directions dated 20.2.2014 could not be timely complied with.

Accordingly, KPTCL vide its affidavit dated 27.8.2014 (filed on 1.9.2014) requested

the Commission to grant time upto 15.1.2016 for completion of protection audit

remarks. KPTCL has submitted that tender was floated for the subject work, however,

considering the different variety of works involved at various sub-stations spread

across vast geographical area, the bidders requested time extension for preparing

their offers and up-loading their bid documents. The technical bid was opened on

20.2.2015. Since the amount put to tender is ` 77.46 crore, the same was required to

Annexure- VI

12 / 18


be placed before the Board of Director`s meeting. KPTCL has submitted that after

resolution in the Board, LoI would be issued. However, successful bidder would be

given a month`s time to accept LOI and entered into an agreement with KPTCL.

KPTCL has requested to grant extension of time by 15.1.2016 for completion of

Phase-I and Phase-II activities.

15. Karnataka Power Corporation Limited (KPCL) in its affidavit dated 28.3.2015 has

submitted that KPCL, vide its affidavit dated 25.8.2014 had requested for grant of

additional time to comply with the directions in order dated 20.2.2014 in Petition No.

146/MP/2013. KPCL has filed the status of implementation of recommendations of

Third Party Protection Audit Committee pursuant to the Commission`s direction dated

15.1.2015. KPCL has stated that out of 33 observations of Third Party Protection Audit

in Phase-I activities, 13 observations have been complied with and out of 21

observations for Phase-2 activities, 6 observations have been complied with.

However, the remaining activities could not be complied with till date due to (a) delay

in obtaining approvals from technical committee before issuing tender notification, (b)

clarifying the bid queries from the bidders, (c) evaluation of technical bid, (d) obtaining

approvals from Contract Management Group of KPCL, (e) opening of price bid, the

process of evaluation and (f) obtaining financial opinion from the Finance Department

of Govt. of Karnataka. KPCL has submitted that though the erection works involve

obtaining prior line clearance from the Load Despatch Centre, dismantling of existing

equipment, laying new foundation, curing time of 25 days, erection of new equipment

and commissioning, KPCL is insisting on the contractors to take up the erection works

simultaneously at different project locations and to complete the same at the earliest.

Annexure- VI

13 / 18


KPCL has requested to extend the date of completion of Phase-I and Phase-II works

till 31.10.2015 and 31.12.2015 respectively.

Analysis and Decision:

(A) Case of KSEBL:

16. KSEBL has initiated action to implement the suggestions of protection audit.

However, KSEBL has sought extension of time for completion of Phase-I activities till

31.12.2014, 220 kV Pothencode sub-station till 31.3.2015 and Phase-II till 31.5.2016.

The Commission vide Record of Proceedings dated 1.8.2014 had allowed time to

KSEBL till 31.12.2014 for completion of works in Phase-I of the protection audit.

17. SRLDC, vide its affidavit dated 25.8.2014, has submitted that action like

administrative approval, finalization of specification, tendering process, etc. has

already commenced in case of KSEBL and with consistent effort, it would be possible

to complete all Phase-II items by 12 months. i.e by September,2015. KSEBL has

further submitted that KSEPBL`s request for time till December, 2015 on account of

such reasons as design changes in old sub-stations, modification of bus arrangement,

simultaneous execution of multiple works, etc. appear to be reasonable. According to

SRLDC, works at Iddukki HEP should not be treated as regular R&M works as the

sub-station is very important and critical and the entire works recommended for the

sub-station should be completed by December, 2015/March, 2016. It is noted that the

KSEBL has already initiated actions to attend the protection audit remarks covered

under Phase-I and Phase-II. KSEBL has also submitted detailed time-line for

implementation of the audit remarks. It is pertinent to mention that time for completion

Annexure- VI

14 / 18


of Phase–I of protection audit remarks and for 220 kV Pothencode sub-station of

KSEBL is already over.

18. Noting the submission of KSEBL, SRLDC and SRPC and considering the

actions already initiated by KSEBL for implementation of remarks of protection audit,

we allow time till 31.12.2015 and 31.3.2016 for implementation of Phase-II works and

R&M works at Idduki HEP respectively.

(B) Case of TANTRANSCO:

19. TANTRANSCO has sought time (a) upto 31.5.2015 for completion of Phase-I

activities of providing numerical relays for feeder protection and auto transformer

protection; (b) up to 30.6.2016 for other Phase-I activities such as provision of line

VT, 5 core CT, Time synchronizing with GPS, Distrubance Recorder, Event Logger

and Phase II activities; and (c) up to 30.6.2017 for Renovation and Modernization of

Singarpet, Singaperumalkoil and Tondiarpet 230 kV sub-stations under Phase-III

activities.

20. TANTRANSCO has submitted that due to financial and time constraints, it

could not implement the recommendations of Protection Audit. TANTRANSCO has

further submitted that 6 to 7 Nos. of 230 kV sub-stations are very old and require

additional land and entire civil work has to be done for installation of new equipment. It

is noted that TANTRANSCO has already initiated action for attending the issues

brought in Phase-I and Phase-II of protection audit and due to certain difficulties

projected by TANTRANSCO, it could not implement the remarks of protection audit.

Annexure- VI

15 / 18


21. After considering the submissions of TANTRANSCO, SRLDC and SRPC, it is

noted that TANTRANSCO`s request for time till 31.5.2015 for implementation of

Phase–I activities of providing numerical relays for feeder protection and Auto

transformer protection is already over. We allow time till 30.6.2016 for other Phase-I

activities such as provision of line VT, 5 core CT, Time synchronizing with GPS,

Disturbance recorder & event logger and Phase-II activities. According to SRLDC,

total implementation period is 15 to 16 months for items which involve major

procurement, design changes with major site modification/civil activities. Accordingly,

we allow 16 months time i.e up to 30.11.2016, for Renovation and Modernization of

Singarpet, Singaperumalkoil, Salem and Tondiarpet 230 kV sub-stations from the

issue of the order.

(C) Case of NLC:

22. NLC has sought time upto 31.12.2014 and 31.3.2015 for completion of Phase-

I work of Numerical Relay Retrofitting and for Phase-II works of providing second

battery bank of PLCC respectively. It is noted that the completion dates for Phase-I

and Phase-II of protection audit remarks as requested by NLC are already over.

Therefore, no direction is required in this regard. However, we direct NLC to file a

confirmation report regarding completion of protection audit works for Phase-I and

Phase-II.

(D) Case of KPTCL

23. SRLDC has stated that KPTCL has already completed protection audit

recommendations where there are no additional financial implications. SRLDC has

Annexure- VI

16 / 18


further submitted that on 16.9.2014, KPTCL invited tenders for the completion of

works and LOA is under process. As per the time line given in the tender documents,

the schedule for completion of entire works of Phase-I and Phase-II is January 2016.

SRLDC has stated that to facilitate timely completion, the tender has been processed

by making four geographical packages such that different agencies may

simultaneously work at different areas of the distribution companies of Karnataka.

Considering the submission of KPTCL and SRLDC, we allow time to KPTCL time till

15.1.2016 for completion of Phase-I and Phase-II of protection audit remarks. No

further extension shall be granted in this regard.

(E) Case of KPCL

24. SRLDC has submitted that KPCL is yet to implement number of items of the

Phase-I which do not involve procurement action. However, KPCL vide its affidavit

dated 6.4.2015 has submitted that it has obtained administrative approval for

procurement of material required for protection audit remarks. KPCL has further stated

that it has already completed certain Phase-I as well as Phase-II works. KPCL has

prayed to extend the date of completion for Phase-I and Phase-II works upto

31.10.2015 and 31.12.2015 respectively. Considering the submission of KPCL and

SRLDC, we allow time to KPCL till 31.10.2015 and 31.12.2015 for completion of

Phase-I for Phase-II of protection audit remarks respectively. No further extension

shall be granted in this regard.

25. SRLDC has submitted list of items discussed in special meeting of PCSC

wherein it was proposed that PCSC forum would send the proposal for dropping

Annexure- VI

17 / 18


certain items under protection audit recommendations. In this regard, we are of the

view that the items to be included/excluded while monitoring implementation of

protection audit should be finalized at RPC level in the interest of grid security.

26. We direct SRPC to (a) submit status of protection audit remarks in respect of

APGENCO, NTPC (SR), Talcher, Puducherry, PGCIL (SRTS I & II), MAPS and

TANGEDCO, (b) monitor the status of completion of remarks of protection audit in

respect of all constituents of Southern Region in Protection Coordination Sub-

Committee (PCSC) meetings, and (c) to coordinate periodic protection audit to be

carried out in Southern Region after deliberation in SRPC. All the constituents of

Southern Region are directed to file their status with SRPC on regular basis to

facilitate proper monitoring in PCSC meetings. SRPC is directed to submit bi-annually

status report to the Commission confirming the completion of Phase-I, Phase-II and

R&M works of protection audit remarks of the constituents of Southern Region.

27. The Petition Nos. 86/MP/2014 and 374/MP/2014 are disposed of in terms of

the above.

Sd/- sd/- sd/- (A.S.Bakshi) (A. K. Singhal) (Gireesh B. Pradhan) Member Member Chairperson

Annexure- VI

18 / 18

Additional Agenda for 47th PCSC meeting Page 1

SOUTHERN REGIONAL POWER COMMITTEE

BENGALURU

Additional Agenda for the 47th

meeting of Protection Coordination Sub-Committee

(PCSC-47) of SRPC to be held on 15.09.2015

1. Grid Occurrences

The additional Grid Occurrences to be discussed in the meeting are given below.

Sr.

No.

क्र.स.ं

घटना का वििरण /

Details of Event

तारीख/ Date

& समय

/Time

कारण / Reason शे्रणी/ Category

1 230 kV Bus dead

at Salem

substation

03:50 Hrs at

30-08-15

Link1 feeder Y phase CT failed and all the

feeders & ICT 1, ICT 2 and 230kV breakers

got tripped at the same time.

2 765 kV

RAICHUR -

SHOLAPUR 1

and 2

04-09-2015

at 19:25 hrs

Sholapur -1 and 2 Feeder got tripped at

Raichur end on operation of over current

protection in Main-1 distance relay and

holding from Solapur end on 04.09.2015 at

19:24:42 Hrs

3 765 KV

RAICHUR –

KURNOOL 2

04-09-2015

at 19:25 hrs

Kurnool -II Feeder got tripped on B-N fault

and holding from Kurnool end (successfully

auto-reclosed at Kurnool end) subsequently

tripped at other end on operation of Over

Voltage stg-1 protection at Raichur end on

04.09.2015 at 19:24 Hrs

2. Review of implementation of certain Protection Audit Recommendations of SR-Constituents

Based on the status updates received from APGENCO, APTRANSCO, TANGEDCO, TANTRANSCO &

PGCIL (SR-II) w.r.t. implementation of protection audit recommendations of their stations, certain recommendations, as brought out in Annexure-VII, are proposed to be reviewed for implementation.

3. Non- furnishing of Tripping Details

The members were intimated about non- furnishing of tripping details for the grid incidents that

occurred during the period 16th

- 31st Aug, 2015 vide SRPC letter dated 08.09.2015 (Annexure-

VIII). The issue would be discussed in the meeting.

4. Revision in Special Protection Scheme

Based on SRPC’s requests to review various SPS’s that have bearing on SR in view of the changed and

anticipated grid conditions, NLDC has carried out extensive load-flow studies for secure operation of All

India Grid considering the anticipated commissioning of 765 kV Kolhapur-Narendra D/C and 765 kV

Additional Agenda for 47th PCSC meeting Page 2

Aurangabad – Sholapur D/C, and suggested for certain modifications in the existing SPS’s along with

installing some new SPS’s on a few transmission lines. These modifications & suggestions given at Annexure-IX are proposed to be deliberated in the meeting to ascertain the views of SR-Constituents.

*****

1220 KV- Dr. NTTPS, Stage-I, 220

KV Switch yard. VTS (Phase-II)

Only 220 V DC Source with one battery set is

available for entire 220 kV SS.It is recommended

to have redundant DC source.

Redundant 220 kV DC supply is available from station

Battery Bank.

2 220KV Bommur Substation REF is not used in APTRANSCO for 220KV

Substations

Differential protection is used for Transformers in

220KV Substations.

Latest Update as on 26-08-2015:

At present differential protection is used as main

problem and O/C and E/F protection as a back up

protection for Transformers in 220KV Substations.

Requested to drop the audit vide lr. no.273 dt.5-5-2015

3 220KV Chittor SubstationAuto reclosure to be made functional for 220 kV

feeders.

On 220KV feeders Auto recloser function not used in

APTRANSCO system.

4 220KV Renigunta sub stationAuto reclosure to be made functional for 220 kV

feeders.


APTRANSCO system.

5 220kV Sullurpet Substation Enabling of Auto recloser in all 220kV feeders.


APTRANSCO system.

Latest Status Updated (as on 10-04-2015):


APTRANSCO system and will be taken as per the

instructions of System Protection Wing.

6 400KV Chittor substationAuto reclosure to be made functional for 220 kV

feeders.


APTRANSCO system.

7 230 kV Basin Bridge SubstationNo Earth fault protection on HV & LV side of

transformer. Same to be provided

E/F settings for AUTOs not being adopted in

TANTRANSCO.

8 230 kV Ennore (ETPS)

Earth fault relay to be provided on HV & LV sides of

Auto t/p # 1, 2 and TO # 3 t/f. Over fluxing relayto be

provided.

E/F settings for AUTOs not being adopted in Tantransco.

9 230 kV Korattur SubstationNo E/L relay protection on ATR 1, 2 & 3 HVs. Same to

be providedE/F settings for AUTOs not being adopted in Tantransco.

10 230 kV Mylapore SubstationNo Earth fault protection on HV & LV side. Same to be

reviewed and providedE/F settings for AUTOs not being adopted in Tantransco.

11 230 kV Tondiarpet Substation

100 MVA, 230/110 kV transformer # 1 &2, back up

O/C relays setting need review. Earth fault relays to be

provided on both HV & LV side of ICT's

Uniform setting adopted for O/C. E/F settings for AUTOs not

being adopted in Tantransco

12

400 kV Kochi SS220V Battery bank-1&2 for protection system to be

replaced with lead acid batteriesVRLA batteries are inline with the standard guidelines

Review of implementation of certain Protection Audit Recommendations of SR-Constituents

PGCIL-SRII (Phase-II)

APTRANSCO (Phase-I)

APGENCO (Phase-II)

TANGEDCO (Phase-I)

TANGEDCO (Phase-I)

Annexure-VII (PAR-Review)

Annexure- VIII

1

Annexure- VIII

2

Annexure- VIII

3

Annexure- VIII

4

Annexure- VIII

5

Annexure- VIII

6

Annexure- VIII

7

Annexure- VIII

8

Annexure- VIII

9

CIN No.: U40105DL2009GOI188682Annexure- IX (SPS-Revisions)

1 / 18

Copy for kind information to:

1) Member (GO & D), CEA, Sewa Bhawan, R. K. Puram, New Delhi-110 066

2) Chief Operating Officer, CTU-Planning, POWERGRID, Gurgaon

3) Executive Director, SRLDC, Bangalore

4) General Manager ERLDC, Kolkata

5) General Manager, WRLDC, Mumbai

Annexure- IX (SPS-Revisions)

2 / 18

1

Power System Operation Corporation Limited National Load Despatch Centre

New Delhi

07th Sep 2015

A. Assessment of WR-SR Transfer Capability considering 765kV Aurangabad-Sholapur D/C and the likely flow pattern

Assumptions in Base-case load flow study are as follows:

765kV Aurangabad-Sholapur D/C is considered.

765kV Kolhapur – Narendra (to be initially charge at 400kV) is not considered.

Power flow on Bhadrawati BTB HVDC: 1000 MW.

Power flow on Talcher-Kolar Bipole HVDC: 2000 MW.

Power flow on Gazuwaka BTB HVDC: 500 MW.

Maximum permissible loading considered for 765kV lines is 2500 MW under (n-1)

contingency.

Maximum permissible loading considered for 400 kV lines under (n-1) contingency is

thermal limit.

Thermal limit of 400kV Kolar-Hosur line is considered as 1100 MVA based on the

certification given by POWERGRID.

Based on the above assumptions, the load flow studies has been carried out and it has been

observed that WR-SR transfer capability would be in the 3500-4000 MW and the limiting

constraint would vary depending on Load-generation and network topology. The table below

gives the WR-SR corridor transfer capability with different conditions:

S. No.

Condition TTC (MW) ATC (MW) Limiting constraint

1 Assuming 765kV line limit as 2500 MW

3500 2750 (n-1) contingency of 765kV Raichur-Sholapur leads to 2500MW on other

circuit

2 If RTPS generation is full ~3600 2850 (n-1) contingency of 765kV Raichur-Kurnool leads to 874 MVA on 400kV

RTPS-Mahaboobnagar S/C

3 If RTPS generation is generating around 1100 MW

~4000 3250 (n-1) contingency of 765kV Raichur-

Kurnool leads to overloading of 2*1500 MVA ICTs at Raichur Substation

Note: TTC/ATC figures may vary depending on the network topology and Load-Generation Balance and the above figures are only representative.


3 / 18

2

With the above TTC/ATC figures, the flow on 2*765kV Raichur-Sholapur S/C would be in the

range of 2500 MW to 3000 MW and flow on 765kV Aurangabad-Sholapur D/C would be in the

range of 3000 MW to 3500 MW. Considering the above power flows on 765kV lines, certain

modifications have to be carried out in existing SPS and new special protection schemes needs

to be installed on 765kV Aurangabad-Sholapur D/C. The table given below shows the angular

difference between 400 kV Jindal (Chhattisgarh) and 400kV Cochin (Kerala) for different

conditions:

S. No. Condition Ang. diff (deg)

1 Base case with 2500 MW limit on 2*765kV Raichur-Sholapur S/C 95.54

2 Outage of one circuit of 765kV Aurangabad-Sholapur D/C 102.14

3 Outage of one circuit of 765kV Raichur-Kurnool S/C 110.56

Single Line Diagram of the relevant portion of the All India grid indicating the power flows and voltage is enclosed at Annexe. Accordingly, the revised SPS settings are indicated in the Table below at B. No change is proposed in respect of Talcher-Kolar SPS.


4 / 18

3

B. Modifications Suggested in the Special Protection Schemes (SPS) – NEW-SR Corridor

S.

No

SPS

Name

Triggering criteria for SPS (implemented) Proposed revision in SPS Remarks

1 SPS-1

(Both

lines in

service)

765kV Sholapur-Raichur flow > 1500 MW:

Total flow on 2*765 kV Sholapur-Raichur S/C lines

crossing a pre-set value of 1500 MW in Sholapur to

Raichur direction and remains above 1500 MW for 2.5

seconds.

SPS Actions:

800MW Gen Back down in WR: JPL-150 MW, JPL extn –

150 MW, KSK – 100 MW, LANCO – 100MW, DB Power –

100 MW, KWPCL – 100 MW, BALCO – 50 MW, NSPCL –

50 MW

500 MW Load shedding in SR: TN – 146 MW, Kerala –

125 MW, Karnataka – 104 MW, AP – 125 MW

Note: Loads identified for shedding in SR for this SPS

action is same as the Loads identified for shedding in SR

for Trip Signal-3 of Talcher-Kolar.

Suggestion: SPS should trigger when total flow on 2*765 kV Sholapur-Raichur S/C line crosses 3500 MW and remains above 3500 MW for 5 seconds. SPS Actions:

In addition to the SPS actions already implemented, the following actions may also be taken: - Loads identified for shedding in SR

for this SPS action is same as the Loads identified for shedding in SR for Talcher-Kolar Trip Signal-3.

- Different set of loads (500 MW) shall be identified and the trip command should be given to these new identified loads only.

- Additional loads to the tune of 500–1000 MW shall be identified for load shedding in Southern Region.

Rationale: WR-SR TTC would be in the range of 3500 MW to 4000 MW, the total flow on both the circuits of 765 kV Raichur-Sholapur would be in the range of 2500-3000 MW. Higher value of line flow for SPS action (i.e., 3500 MW) is chosen so as to avoid frequent operation of SPS. This would also ensure that in the event of tripping of Bhadrawathi HVDC or Gazuwaka HVDC or Talcher-Kolar HVDC or Kudankulam Unit-1, the SPS-1 would get activated and keep the system secure.


5 / 18

4

S.

No

SPS

Name


- So in total there would be a total of 1000-1500 MW load shedding in Southern Region for this SPS.

2 SPS-1

(Both

lines in

service)

765kV Sholapur-Raichur flow > 1500 MW:

Total flow on 2*765 kV Sholapur-Raichur S/C lines

crossing a pre-set value of 2000 MW in Sholapur to

Raichur direction sensed both at Sholapur and Raichur --

- Instantaneous triggering.

SPS Actions:




50 MW



Suggestion: SPS should trigger when the total flow on 765 kV Sholapur-Raichur 2*S/C crosses 4000 MW and remains above 4000 MW for 2.5 seconds.

SPS Actions:

In addition to the SPS actions already implemented, the following actions may be taken: - Loads identified for shedding in SR

for this SPS action is same as the Loads identified for shedding in SR for Talcher-Kolar Trip Signal-3.

- Different set of loads (500 MW) shall be identified and the trip command should be given to these new

Rationale: As compared to proposed SPS setting at S.No-1, additional 500 MW margin has been taken for activating the SPS. Further, the time delay has been reduced to control the line loading immediately. Additional 1000 MW loads has to be identified for further load shedding.


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5

S.

No

SPS

Name





identified loads only. - Additional loads to the tune of 500–

1000 MW shall be identified for load shedding in Southern Region.


3 SPS-1

(Only

One

line in

service)

765kV Sholapur-Raichur S/C flow > 1000 MW:

Total flow on 765 kV Sholapur-Raichur S/C lines crossing

a pre-set value of 1000 MW in Sholapur to Raichur and

remains above 1000 MW for 2.5 seconds.

SPS Actions:




50 MW





Suggestion: SPS should trigger when one of the two ckts of 765 kV Raichur-Sholapur is out and the flow on other 765 kV Sholapur-Raichur S/C line crosses 2000 MW and remains above 2000 MW for 2.5 seconds (i.e. SPS should act in case of outage / tripping of one circuit and flow on the other circuit greater than 2000 MW). SPS Actions:

In addition to the SPS actions already implemented, the following actions may be taken: - Loads identified for shedding in SR

for this SPS action is same as the

Rationale: Tripping of one 765kV circuit would lead to heavy flow on second circuit. Consider both Raichur-Sholapur ckts are carrying 2900 MW. Tripping of one circuit would lead to 2900 MW on second circuit. Many a times in the past, it was observed that both Raichur-Sholapur ckts have tripped leading to NEW-SR separation. Considering FRC of SR in the tune of 1500-2000MW, tripping of both Raichur-Sholapur ckts at this level of flow might lead to frequency dip of 0.7–1.2 Hz in SR. Considering frequency of 50 Hz, there will be high probability of 49.2 Hz UFR operation in SR. This means that the load shedding for SPS-1 should be such that it should not consist of loads, which are for UFR operation.


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6

S.

No

SPS

Name


for Trip Signal-3 of Talcher-Kolar. Loads identified for shedding in SR for Talcher-Kolar Trip Signal-3.

- Different set of loads (500 MW) shall be identified and the trip command should be given to these new identified loads only.

- Additional loads to the tune of 500–1000 MW shall be identified for load shedding in Southern Region.


Further, 765kV Kolhapur (New)-Narendra (New) D/C (to be initially charged at 400kV) is likely to be commissioned in the same period. Load flow studies indicate that tripping of both Raichur-Sholapur circuits carrying more than 1500 MW would cause voltages at 400kV Kolhapur, 400kV Mapusa, 400kV Narendra sub-stations to go below 370kV. This might cause grid disturbance in Kolhapur area, Goa and also in SR. In case of planned outage of one of the 765 kV Sholapur-Raichur S/C, TTC on WR-SR would reduce drastically by 2000-2500 MW; so actual flows would be much lower and this SPS would ordinarily not be required to operate unless there is a large contingency in SR.


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7

S.

No

SPS

Name


4 SPS-1

(Only

One

line in

service)

765kV Sholapur-Raichur S/C flow > 1500 MW:


a pre-set value of 1500 MW in Sholapur to Raichur ---

Instantaneous triggering

SPS Actions:




50 MW






Suggestion: This may be blocked

S no 3 above should be ok.


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8

S.

No

SPS

Name


5 SPS-3 Loss of 765kV Sholapur-Raichur lines carrying 800 MW

towards SR:

Loss of import of SR on 765kV Sholapur-Raichur section

by more than 800 MW due to tripping of these lines.

SPS Actions:



Suggestion: SPS should trigger when loss of import of SR on 765kV Sholapur-Raichur section due to tripping of these lines is more than 1500 MW.

SPS Actions:

Loads identified for shedding in SR for

this SPS action is same as the Loads

identified for shedding in SR for

Talcher-Kolar Trip Signal-3.

Different set of loads (500 MW) shall be

identified and the trip command should

be given to these new identified loads

only.

Additional loads to the tune of 500–

1000 MW shall be identified for load

shedding in Southern Region.

So in total there would be a total of 1000-1500 MW load shedding in

Rationale: From the past data, it is observed that SR FRC is in the range of 1500 MW – 2500 MW. Hence, 1500 MW has been selected for SPS action. In SR, to arrest a sharp frequency fall, additional load shedding to the tune of 1000–1500 MW through SPS shall be identified.


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9

S.

No

SPS

Name


Southern Region for this SPS.

6 SPS-4 400kV Raipur – Wardha D/C:

Flow on either circuit of 400 kV Raipur – Wardha D/C

crossing 850 MW and remaining above this value for 2.5

seconds

Or

Tripping of any one circuit of 400 kV Raipur – Wardha

D/C carrying 700 MW or above

SPS Actions:




50 MW



Suggestion: SPS settings may be retained.

SPS Actions:




Kudankulam Unit tripping.

Hence, different set of loads (500 MW) shall be identified for tripping and should be different from the loads identified from Kudankulam Unit tripping.

Loads to the tune of 200-300 shall also

be identified for tripping in Western

Rationale:

This would not be an issue after

commissioning of 765kV Raipur-Wardha

Ckt-3 & 4 which are expected by next 3-4

months.

WRPC may kindly ensure load shedding

of 200-300 MW in Western

Maharashtra.


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10

S.

No

SPS

Name


Maharashtra for shedding.

7 SPS-5 400kV Wardha - Parli D/C:

Flow on either circuit of 400 kV Wardha - Parli D/C


seconds

Or

Tripping of any one circuit of 400 kV Wardha - Parli D/C

carrying 750 MW or above

SPS Actions:




50 MW



Suggestion: SPS settings may be retained as it would help in case of tripping of 765kV Aurangabad-Sholapur D/C. SPS Actions:





Hence, different set of loads (500 MW) shall be identified for tripping and should be different from the loads identified from Kudankulam Unit

WRPC may kindly ensure load shedding

of 200-300 MW in Western

Maharashtra.


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11

S.

No

SPS

Name


tripping. Loads to the tune of 200-300 shall be

identified in Western Maharashtra for

shedding.

8 SPS-6 400kV Parli – Sholapur D/C:

Flow on either circuit of 400 kV Parli – Sholapur D/C


seconds

Or

Tripping of any one circuit of 400 kV Parli – Sholapur

D/C carrying 700 MW or above

SPS Actions:




50 MW



Suggestion: SPS settings may be retained as it would help in case of tripping of 765kV Aurangabad-Sholapur D/C.

SPS Actions:





Hence, different set of loads (500 MW) shall be identified for tripping and should be different from the loads identified from Kudankulam Unit tripping.

Rationale:

This SPS would act as back-up in case of failure of 765kV Aurangabad-Sholapur D/C tripping SPS. WRPC may kindly ensure load shedding of 200-300 MW in Western Maharashtra.


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12

S.

No

SPS

Name


Loads to the tune of 200-300 shall be

identified in Western Maharashtra for

shedding.

9 SPS-7

(Only

One

line in

service)

765kV Raichur-Sholapur line current exceeding 800

Amp (1000 MW on either direction):


a pre-set value of 1000 MW (800 Amps) in Sholapur to

Raichur and remains above 1000MW for 10 seconds ---

Trips the line

Suggestion: Line tripping to be blocked

Rationale: Tripping of line would lead to unnecessary separation of NEW grid and SR grid. Hence, tripping of line through SPS should be blocked.


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13

A. Proposed Special Protection Schemes (SPS)

S.

No

SPS Name Proposed Triggering criteria for SPS (implemented) SPS action required Remarks

1 SPS-8

(Both lines

in service)

765kV Aurangabad-Sholapur D/C flow > 2000 MW

Tripping of 765kV Aurangabad-Sholapur D/C carrying a pre-set value of 2000 MW

in Aurangabad to Sholapur direction.

Load shedding in SR: Quantum of load shedding for each case is indicated in the Table-1. Generation Back-down in WR: Approximately 500 - 1000 MW generation may be backed down from generators in W3 area.

Rationale:

SR load is having 80% sensitivity on 765kV Aurangabad-Sholapur line loading. In case of Outage of one circuit of 765kV Aurangabad-Sholapur D/C, the angle between 400kV Jindal and 400kV Cochin goes above 100 degrees. D/C loss should be properly detected by the SPS.

2 SPS-8

(Both lines

in service)




3 SPS-8

(Both lines

in service)




4 SPS-9 765kV Raichur - Kurnool S/C flow > 2000 MW

Tripping of 765kV Raichur - Kurnool S/C carrying a pre-set value of 2000 MW in

Raichur to Kurnool direction.

Load shedding in SR: 500 MW -1000 MW

Tripping of 765kV Raichur-Kurnool line above 2000MW would lead to overloading of 2*1500 MVA ICTs at Raichur. Hence, it would be better to


15 / 18

14

S.

No

SPS Name Proposed Triggering criteria for SPS (implemented) SPS action required Remarks

shed the load to the tune of 500-1000 MW, so that system remains intact and secure.

Table-1: Load shedding requirement in SR and Maharashtra due to tripping of 765kV Aurangabad-Sholapur D/C

S. No.

Condition Flow on both

Circuits (A)

Flow on Sholapur-Raichur (B=

A*0.8)

Maximum Allowable flow on Sholapur-Raichur D/C without 765kV Aurangabad-Sholapur D/C

Load shedding required in SR

1 Tripping of 765kV Aurangabad-Sholapur D/C 2000 1600 1300 300





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15

Load Groups identified for SPS actions (Presently Implemented): S. No.

SPS Name Load Group – 875 MW

Load Group – 780 MW



1

Talcher-Kolar HVDC Trip Signal-1 - Loss of power flow on HVDC greater than 500 MW but less than 1000

MW (OR) - Tripping of one pole and HVDC flow prior tripping greater than 1000

MW but less than 1500 MW

√ (Kar-250, AP-230,

TN -395) - - -

2

Talcher-Kolar HVDC Trip Signal-2 - Loss of power flow on HVDC greater than 1000 MW (OR) - Tripping of one pole and HVDC flow prior tripping greater than 1500

MW

- √ (Kar-200, AP-240, TN -170, Kerala-170)

- -

3

Talcher-Kolar HVDC Trip Signal-3 - Loss of power flow on HVDC greater than 2000 MW (OR) - Tripping of one pole and HVDC flow prior tripping greater than 2000

MW

- - √ (Kar-104, AP-125, TN -146, Kerala-125)

-

4 Kudankulam Unit Tripping

- -

-

√ (Kar-193, AP-230, TN -290, Kerala-135)

5 SPS-1 (765kV Sholapur-Raichur flow > 1500 MW) - - √ -

6 SPS-3 (Loss of 765kV Sholapur-Raichur lines carrying 800 MW towards SR) - - √ -

7 SPS-4 (400kV Raipur – Wardha D/C flow > 850 MW/ckt) - - - √

8 SPS-5 (400kV Wardha - Parli D/C flow > 850 MW/ckt) - - - √

9 SPS-6 (400kV Parli – Sholapur D/C flow > 800 MW/ckt) - - - √

10 SPS-7 (765kV Raichur-Sholapur line current exceeding 800 Amp (1000 MW on either direction)

- - √ -

1. Loads identified for shedding in SR for SPS-1 & SPS-3 are same as the loads identified for load shedding in SR for Trip Signal-3 of Talcher-

Kolar HVDC. 2. Loads identified for shedding in SR for SPS-4, SPS-5 & SPS-6 are same as the loads identified for load shedding in SR for Kudankulam

unit tripping.


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16

Observations based on load groups identified for SPS actions:

1. Loads identified for SPS-1, 3, 4, 5 & 6 shall be different from Talcher-Kolar HVDC SPS loads and Kudankulam SPS loads.

2. With the commissioning of 765kV Aurangabad-Sholapur D/C, 765kV and 400kV lines loadings are likely to increase drastically with

operationalization of LTA. Loads identified for SPS shall be different from the loads identified for UFR.

3. In the event of tripping of single circuit or both circuits of 765kV Raichur-Sholapur, a signal may be sent to Talcher-Kolar HVDC for

ramping up the HVDC set-point to 2500MW. This would reduce the overloading of AC lines in WR-SR corridor.

Notwithstanding the above revisions suggested, the following are also important.

Improving reliability of SPS through redundant measurements, logic and communication path and end terminals.

Use of metering core of CTs and PTs for analog measurements used in the SPS logic, particularly where the same is based on steady

state flows crossing a particular value.

Need to cover more generators in the NEW grid so that adequate relief is available as in many instances, the antecedent generation in

many of the generators selected is already very low.

Wiring of each SPS operation to the local substation Event Logger.

Triggering of each SPS action and the receipt of signal at each point to be recorded in SLDC/RLDC/NLDC SCADA

Prompt submission of data to RLDCs regarding SPS action in the prescribed format.

Each instance of inadequate relief through SPS to be thoroughly analysed and remedial actions taken so as to have increased

confidence on the SPS reliability.


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· pdf fileconstituents are requested to bring/ give full particulars for the tripping ......

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