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Agenda for the 67th Meeting of PCSC scheduled to be held on 20th September, 2017 Page 1

SOUTHERN REGIONAL POWER COMMITTEE

BENGALURU

Agenda for the 67th Meeting of Protection Coordination

Sub-Committee of SRPC to be held on 20th September, 2017

1. Introduction

2. Confirmation of Minutes of last PCSC meeting

Confirmation of minutes of 66th

Protection Coordination Sub-Committee meeting held

on 17.08.2017.

3. Grid Occurrences

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

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

period July - August, 2017 given at Annexure-I would be discussed in the PCSC

meeting.

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

above grid occurrences to have fruitful discussions.

(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/ furnish full particulars of the tripping

events pertaining to their system.

3.2 In compliance of Regulations 5.2 (r) of IEGC, the Constituents are required to

furnish the following information in respect of Grid Occurrences within 24 hrs of

occurrence of the same to SRLDC/ SRPC:

(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 (FIR/DR/EL/TR) for the period 01.15.2017 –

15.07.2017 had been brought to Constituents’ notice vide letters (i) No. SRPC/

SE-III/ PCSC/ 2017/4681 - 85 dated 22.06.2017, (ii) No. SRPC/ SE-III/ PCSC/ 2017/

3892 - 96 dated 07.07.2017, and No. SRPC/ SE-III/ PCSC/ 2017/ 4837 - 41 dated

18.08.2017. Non-compliance in this regard would be discussed in the meeting.

4. Submission of Reports/Compliance by Constituents

4.1 Status of implementation of pending Protection Coordination

Sub-Committee (PCSC) Recommendations

Status of implementation of pending PCSC recommendations (up to 66th

PCSC

meeting) given at Annexure-II may please be sent latest by 15.09.2017.


4.2 Remedial measures for "Transmission Elements under Forced Outage"

· The Constituents are requested to furnish the remedial measures/ action

taken by them for the tripping events as circulated vide our emails.

(Annexure-III)

· The tripping 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 have been requested to submit the

certificate on healthiness of batteries on monthly basis (i.e. status for a

month shall be sent by the 7th

day of the following month) to SRPC

Secretariat.

· The sought status for the month of August, 2017 is awaited from the

following SR-Constituents:

TSGENCO (Hydro), TANGEDCO, TANTRANSCO, PED, PGCIL (SR-I),

NPCIL (MAPS), NTECL, UPCL, JSWEL & NTPL

5. Revised Over Voltage Relay (OVR) Gradings for certain 400 kV & 765 kV lines

After issuance of new OVR gradings for 400 kV and 765 kV transmission lines of

southern region in April, 2017 (issued vide SRPC letter no: SRPC/ SE-III/ OVR/ 2017/

2023-53 dated 17.04.2017), certain reconfigurations took place (i) in the 400 kV system

belonging to APTRANSCO, TSTRANSCO and PGCIL (SR-I), and (ii) 765 kV system of

PGCIL (SR-I) in the past few months, which necessitated revising OVR gradings for the

transmission lines emanating from corresponding stations.

In this regard, necessary studies (Annexure-IV) have been carried out to arrive at

proper OVR gradings for these lines. Accordingly, APTRANSCO, TSTRANSCO and

PGCIL (SR-I) are directed to implement the new/ revised OVR gradings given at

Annexure-V pertaining to their respective systems with immediate effect.

6. Implementation of Protection Suite / Protection Management System (PMS)

for Southern Region

To familiarize SR-Constituents about the modus operandi of subject project execution,

kick-off meetings with M/s PRDC Pvt. Ltd. (Executing Agency) have been arranged as per

the following schedule (Letters in this regard have already been addressed to all

concerned vide our letter no: SRPC/ SE-III/ PMS/ 2017/ 4884 – 978 dated 24.08.2017):


Date & Time Venue Constituent Utilities

21.09.2017

from 10:00 hrs

Conference Hall of

SRPC Secretariat,

Bengaluru

Kerala, CPSUs and IPPs as indicated in

above referred letter

22.09.2017

from 10:00 hrs

Conference Hall of

SRPC Secretariat,

Bengaluru

Andhra Pradesh, Telangana, Karnataka,

TamilNadu, and Puducherry as

indicated in above referred letter

In the said meetings, the following would be presented by the Executing Agency:

· Introduction on the project

· Scope of the work: Different works and deliverables involved in the project will be

presented.

· Methodology: In this section clear methodology will be presented on how to go

about different works and complete them in stipulated time. Methodology for

following will be explained:

Ø Data collection and Database updating for SCADA validation, Geographical

diagram for the Southern states, plan for data collection, relay data extraction

from substations and Bus breaker model for all the substations.

· Case Study of data collection and database modelling, bus-breaker modelling

conducted for few substations in Bengaluru.

· Expectations from SR Constituents

· Time-lines and Deliverables of the project

· PRDC project team

· Discussions

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

8. 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.

9. Date of next PCSC meeting

It is informed that the 68th

meeting of PCSC will be held on 26th

October, 2017

(Thursday) from 10:30 hrs onwards in the Conference Hall of SRPC Secretariat,

Bengaluru.

*****

Grid Occurrences to be discussed in the 67th Meeting of PCSC scheduled to be held on 20th September, 2017 1/5

Grid Occurrences - 67

For all tripping events involving failure of substation equipment, Constituents are requested to

kindly furnish the SLD or equivalent pictorial representation showing (i) Location of the fault,

and (ii) Bus-bar arrangement/ Configuration of feeders and other connected equipment with

proper CB positions (OPEN/ CLOSE) at the time of occurrence of the fault.

I. Details of Grid Disturbances:

Sl. No.

Details of Event Date & Time Reason Remarks Category

1

Complete outage of

230kV Mettur

substation of Tamil

Nadu

13-07-2017

at 10:33 hrs

Flashover occurred during

transferring Unit-I (GT-I)

from main breaker to

transfer breaker

Gen loss

570 MW GD-1

2

Complete outage of

230kV Karamadai

substation

01-08-2017

at 3:40 hrs

Triggering incident was B-

phase PT failure in 230kV

Bus at Karamadi. Bus bar

protection operated

resulting in tripping of all

the connected elements

------ GD-1

3

Complete Outage of

230kV Tharamani

Subsation of

TANTRANSCO

02-08-2017

at 11:55 hrs

Jumper cut between bus

isolator and CT on Y-phase

of 230kV Tharamani –

Sholinganallur feeder

leading to operation of bus

bar protection.

Load loss

236MW GD-1

4

Complete Outage of

400kV Coastal energen

power Station

09-08-2017

at 17:54 hrs

400kV Coastal Energen -

Tuticorin PS Ckt-1 & 2

tripped due direct trip

receive in PLCC Channel-2.

Running units of Coastal

Energen also tripped due to

tripping of the evacuating

lines.

Gen loss

554 MW GD-1

5

Complete Outage of

220kV Nagjheri Power

House.

11-08-2017

at 19:51 hrs

while desynchronizing Unit-

3, R-phase of Generator

Circuit Breaker did not open

due to mechanical problem.

LBB of Unit-3 CB and this

tripped all the six lines

Gen loss

440 MW GD-1

6

Complete Outage of

400kV Coastal energen

power Station

19-08-2017

at 11:09 hrs

400kV Coastal Energen -

Tuticorin PS ckt-1&2 got

tripped due direct trip

receive in PLCC Channel-2.

Running units of Coastal

Energen also tripped due to

tripping of the evacuating

lines. There was no tripping

of breakers at Tuticorin PS

end.

Gen loss

325 MW GD-1


II. Details of Grid Incidents:

Sl. No. Details of Event Date & Time Reason Category

1 Tripping of 400 kV

RTPP-Chitoor line-2

2-07-2017

2017 at

00:27 & 1:08

hrs

line tripped on operation of over-voltage

stage-1 protection at RTPP and direct trip

received at Chittoor

GI-2

2

Tripping of 765/400kV

ICT-2 at Vemagiri

substation

03-07-2017

at 10:34 hrs

ICT-2 at Vemagiri GIS tripped on

maloperation of PRV-2 of Spare

transformer unit

GI-2

3

Tripping of 400/220kV

ICT-1 at Uruvakonda

substation

04-07-2017

at 2:01 hrs

ICT-1 tripped o mal-operation of Tie LBB

protection GI-2

4 Tripping of 765/400kV

ICT-2 at Kurnool

04-07-2017

at 15:06 hrs

765/400kV ICT-2 tripped due to mal-

operation of 86B trip relay GI-2

5 Tripping of HVDC

Bhadravati Pole-1

07-07-2017

at 10:59 hrs

Pole-1 tripped due to PC1 INTERNAL

MINOR ALARM WEST - ALARM. Pole

protection extended trip without any

protection operation.

6 Tripping of HVDC

Bhadravati Pole-1

09-07-2017

at 14:43 hrs

Pole protection initiated trip without any

protection operation

7 Tripping of 400kV

JSWEL - Guttur line

09-07-2017

at 18:02 hrs

& at 02:05

hrs on 24-07-

2017


stage-1 protection at Guttur end and

direct trip was received at JSW.

GI-2

8 Tripping of 400/220kV

ICT-1 at SVChatram

14-07-2017

at 19:03 hrs

400/220kV ICT-1 at S.V.Chatram tripped

on operation of Low impedance REF

protection during R phase to earth fault

in 400kV Alamathy-SVChatram line-2

GI-2

9 Tripping of HVDC

Talcher Kolar Pole-1&2

23-07-2017

at 17:07 hrs

Auxilliary supply failure at Talcher end led

to tripping of valve cooling pumps of

HVDC which in-turn led to tripping of

HVDC pole-1&2 at Talcher and emergency

switch off signal (ESOF) was sent to Kolar

end. Load relief in SR due to SPS

operation was 564 MW.

10 Tripping of 400/110KV

Alamathy ICT-2

24-07-2017

at 9:13 hrs

ICT-2 tripped due to suspected mal-

operation of high impedance REF

Protection

GI-2

11

Tripping of 400kV

Vijayawada TPS –

Malkaram and

Vijayawada TPS –

Suryapet

29-07-2017

at 19:33 hrs

Triggering incident was failure of Y-phase

CT occurred in 400kV VTPS-Malkaram

feeder at VTPS end.

GI-2


12 Tripping of HVDC

Gazuwaka Pole-1

03-08-2017

at 12:16 Hrs

Gazuwaka Pole-1 tripped due tomal-

operation of power supply card leading to

the stalling of the valve base electronics

13

Tripping of 400 kV

NCTPS – Vallur-2 and

NCTPS-Manali

04-08-2017

at 02:01 hrs

R-phase to ground fault occurred in

400kV NCTPS – Manali line. bus bar

protection of Bus-1 got operated at

NCTPS

GI-2


Kaiga-Kadra line

11-08-2017

at 14:29 hrs

line tripped on B-phase to earth fault in

zone-1 from Kadra GI-1

15

Tripping of 400/220 kV

ICT-3 at N’Sagar

substation

13-08-2017

at 20:51 hrs

Mal-operation of ICT differential

protection GI-2

16 Tripping of 400/220 kV

ICT -3 at Nagarjunsagar

22-08-2017

at 10:21 hrs Mal-operation of 86B trip relay GI-2


Kolar-Thiruvalam line

26-08-2017

at 1:58 hrs

hrs & 2: hrs

on 27-08-

2017

line tripped due to operation of

overvoltage protection at Kolar and direct

trip was received at Thiruvelam end.

considerable difference between R, Y and

B phase voltages

GI-2

18

Tripping of 400kV

Maheshwaram-

Narnoor line

30-08-2017

at 10:11 hrs

86B relay mal-operation at

Maheshwaram caused tripping of line and

direct trip was received at Narnoor

GI-2

19 Tripping of 400/220 kV

ICT-2 at Nellore

31-08-2017

at 05:05 hrs

ICT-2 tripped due to mal-operation of

differential relay. GI-2

III. Details of Trippings due to Failure or Non-operation of Auto-Reclose:

Sl. No. Element Date & Time Reason

Category

1

Tripping of 400kV

Gajwel - Bhoopalapalli

line

22-07-2017

at 13:13 hrs

line tripped on B-Phase to earth fault.

Auto-reclose was successful at

Bhoopalapally end and breaker tripped at

Gajwel.

GI-2

2 Tripping of 400kV

Neyveli-Salem line

06-08-2017

at 17:04 hrs

Y-phase to earth fault. Auto reclose was

successful at Salem end

GI-2

3

Tripping of 400kV

N’sagar- Cudappah

line-1

07-08-2017

at 12:20 hrs

R-phase to earth fault. Auto-reclose was

not attempted.

GI-2

4

Tripping of 400kV

Khammam-Asupaka

09-08-2017

at 19:43 hrs

B-phase to earth fault. Line did not

attempt auto-reclose at Khammam end

due to direct trip receive from Asupaka

end.

GI-2

5 Tripping of 400kV 15-08-2017 B-phase to earth fault. Direct trip was


Somanahalli-Bidadi

line-2

at 03:16 hrs sent from Bidadi to Somanahalli during

auto-reclose dead time

GI-2

6

Tripping of 400kV

N'Sagar-Cudappa line-1

19-08-2017

at 3:48 hrs

Y-phase to earth fault. Auto-reclose was

successful at N’sagar and breaker at

tripped at Cudappa end

GI-2

7

Tripping of 400kV

Tirunelveli-Kanarpatti

line

31-08-2017

at 21:58 hrs

R-phase to earth fault had occurred in

line. Breakers got tripped at Tirunelveli

and did not attempt auto-reclose.

GI-2

IV. Details of Trippings due to PLCC mal-operation:

For the following events, concerned Constituents are requested to furnish the remedial action

taken to resolve the issue involved to [email protected] latest by 16.09.2017

Sl. No. Element Date & Time Reason

Category

1

Tripping of 400 kV

Ghanapur-Mamidapalli

line

01-07-2017

at 15:49 hrs

Line tripped at Mamidapalli end only on

direct trip receive. Line was in service

from Ghanapur end.

GI-2

2

Tripping of 400kV

Khammam-Kalpakka

line-2

03-07-2017

at 9:24 hrs

Line tripped on direct trip receive at

Kalpaka end and line was in service from

Khammam

GI-2

3

Tripping of 400kV

Nellore-Thiruvelam

line-2

03-07-2017

at 14:20 hrs

line tripped on DT receipt at Thiruvallam

end only and was in service from Nellore

end

GI-2

4

Tripping of 400kV

Khammam-Kalpakka

line-2

07-07-2017

at 12:03 hrs

line tripped at Kalpakka end only on

direct trip receive and was in service from

Khammam

GI-2

5 Tripping of 400kV

Guttur-Hiryur line-2

22-07-2017

at 15:03 hrs

line tripped at Guttur end only and was in

service from Hiryur. I

GI-2

6

Tripping of 400kV

Ghanapur-Mamidapalli

line

24-07-2017

at 19:35 hrs

&

25-07-2017

at 16:24 hrs

line tripped at Mamidapalli end only on

direct trip receive and line was in service

from Ghanapur.

GI-2

7 Tripping of 400kV

Kaiga-Guttur line-2

25-07-2017

at 5:24 hrs

line tripped at Guttur end only on direct

trip receive and line was in service from

Kaiga.

GI-2

8

Tripping of 400kV

Khammam-

Mamidapalli line-2

31-07-2017

at 13:55 hrs

line tripped at Mamidapalli end on direct

trip receive and was holding from

Khammam

GI-2

9

Tripping of 400kV

Malkaram-Hyderabad

line

31-07-2017

at 15:44 hrs

line tripped at Malkaram end on direct

trip receive and was holding from

Hyderabad

GI-2

10

Tripping of 400kV

Mamidapalli-Dindi line-

2

31-07-2017

at 14:03 hrs

line tripped at Dindi end on direct trip

receive and was holding from

Mamidapalli.

GI-2

11 Tripping of 400kV

Ghani-Narnoor line-1

07-08-2017

at 11:05 hrs

line tripped at Narnoor end only on direct

trip receive and line was in service from

Ghani.

GI-2


Nizamabad-Dichipally

07-08-2017

at 17:12 hrs

line tripped on DT receipt at Dichipally

and was in service from Nizamabad

GI-2


13

Tripping of 400kV

Kalpakka-Gazuwaka

line-1&2

16-08-2017

at 14:40 hrs

line tripped at Kalpaka end only due to

Direct trip receipt at Kalpaka

GI-2


Cudappa-Chitoor line

19-08-2017

at 3:49 hrs

Line tripped at Cudappa end on direct trip

receive & was in service from Chittoor

end

GI-2

15

Tripping of 400kV

Ramagundam-

Ghanapur line-4

20-08-2017

at 1:47 hrs


stg-1 protection at Ghanapur end . Line

was holding from Ramagundam as no

direct trip was received from Ghanapur

GI-2

V. Forced outage of lines due to Over Voltage:

(i) Tripping of 400kV Uravakonda-Jamalamadugu line-2

It was noted that the line had frequently tripped (as given below) on operation of Over

Voltage Protection at Uravakonda in the past two months. Further, Direct Trip was also not

received at Jamalamadugu end, and line was hand tripped in all cases.

Sl. No. Date & Time of tripping Reason

1 24-07-2017 at 2:01 hrs Over Voltage Stg-1 at Uravakonda








à APTRANSCO is requested to present reasons for frequent tripping of the line on

OVR, Stage-I protection, and corrective action taken to sort out the issues involved.

(ii) Tripping of Maheswaram-Narnoor line:

It was noted that the line had frequently tripped (as given below) on operation of Over

Voltage Protection at Narnoor in the past two months. Direct trip was received at

Maheswaram end. However, operation of OVR, Stage-I protection could not be validated

with the submitted DR of Narnoor station.

Sl. No. Date & Time of tripping Reason

1 06-08-2017 at 08:02 hrs Over Voltage Stg-1 at Narnoor







à APTRANSCO is requested to present reasons for frequent tripping of the line on

OVR, Stage-I protection, and corrective action taken to sort out the issues involved.

*****

Meeting No /

Index

Details of Event Date & Time Reason PCSC Recommendations Utility responsible for

Implementation

Status of Recommendations

as on 06.09.2017

Remarks

Pending Implementation of PCSC Recommendations (up to 66th Meeting)

Complete outage of 220kV Yerraguntla

substation and tripping of running Units

at Rayalaseema TPS

52/I/2 (GD) PendingMail received on 27-07-2016:

1.The drop out relays of reducer oil pumps time setting was increased for

all mills.So there will not be any trip under transient low voltage condition.-

---Complied

2.The recommendation regarding 2 sec time delay will be implemented

during unit shut down and will be intimated immediately after

implementation.------Pending

APGENCO 1. APGENCO to check associated logic for lube oil pump for correct

operation under transient low voltage conditions at Rayalaseema TPS,

Unit-1.

2. APGENCO to keep appropriate time delay/ fault ride through

delay (typically 2 sec) in VFD speed sensor relay at all its generating

Units including Rayalaseema TPS Units.

HV B-Ph Current transformer of 100MVA Power

Transformer -1 failed resulting into a bus fault on

220KV Bus-1. Unit-1 and Unit-5 at RYTPS tripped

during the fault at Yerraguntla substation

21-02-2016 at

10:39 hrs

Andhra Pradesh

APGENCO to furnish a report on the remedial action implemented

w.r.t. overreaching of Krishnapatnam end distance relays during the

tripping of 400 kV Nellore (PG) - NPS line-1

APGENCO Yet to be informed Pending57/II/9 Tripping of 400 kV Nellore (PG) - NPS

line-1, 400 kV Krishnapatnam-Nellore

(AP) lines -1&2 and 400kV NPS -

MEPL line

18-07-2016 at

19:05 hrs

Triggering incident was snapping of Y phase

conductor in 400kV Nellore (PG) - NPS line-1.

Distance relay at Krishnapatnam end over-reached in

Zone-1, and resulted in tripping of 400kV

Krishnapatnam – Nellore (AP) lines - 1&2 from

Krishnapatnam end. Distance relay at MEPL over-

reached and resulted in tripping of MEPL-NPS line

from MEPL end.

Yet to be informed Pending

APTRANSCO mail dated on 31-08-2016:

To avoid the unwanted malopeartions due to the external LBB trip

initiation from PGCIL, Vide letter Dt: 04-08-2016, APTRANSCO has

requsted the PGCIL to arrange the Master trip relay and breaker contacts

of ICT-1 &2 LV side to enable the internal LBB feature in the Busbar

protection scheme at 220kV Gooty Switching station. Waiting for the

PGCIL response.


To avoid the unwanted maloperations due to the external LBB trip

initiation from PGCIL, vide letter Dt: 04-08-2016, ARTRANSCO has

requested the PGCIL to arrange the Master trip relay and breaker contacts

of ICT-1&2 LV side to enable the internal LBB feature in the Busbar

protection scheme at 220kV Gooty Switching station. Waiting for the

PGCIL response.


Waiting for the PGCIL response.

APTRANSCO mail dated 04.03.2017 & 24.05.2017.

SRPC is requested to coordinate with PGCIL in takind necessary action.

Pending

Tripping of 400kV Krishnapatnam-

Nellore line-1

Line tripped on B-phase to earth fault and auto-

reclose was successful at Nellore(AP) end and un-

successful at Krishnapatnam end

APGENCO

56/II/13 Tripping at 220kV Gooty Substation of

APTRANSCO

24-06-2016 at

16:04 hrs

LBB protection got operated for 400/220kV ICT-2

breaker which had resulted in tripping of 220kV Bus-

2 at 220kV Gooty Substation

1. APGENCO/ SDSTPS to correct logic and ensure healthiness of A/R

scheme employed for transmission lines emanating from SDSTPS,

and furnish an action taken report to PCSC forum.

2. APGENCO/ SDSTPS to configure DR’s of line protection relays

for a post triggering period of 2 sec to capture complete A/R

operation at their SDSTPS.

Yet to be informed Pending63/III.1 28-02-2017 at

05:16 hrs

1. APGENCO/ SDSTPS to correct logic and ensure healthiness of A/R

scheme employed for transmission lines emanating from SDSTPS,

and furnish an action taken report to PCSC forum.

2. APGENCO/ SDSTPS to configure DR’s of line protection relays


operation at their SDSTPS.


Nellore line-2

R-phase to earth fault had occurred in line. Auto

reclose was successful at Nellore, however

protection at Krishnapatnam end issued a 3 phase

trip

APGENCO63/III.3 02-03-2017 at

4:55 hrs

1.APTRANSCO to check the healthiness of the connecting cable

between Gooty (PGCIL) and Gooty (APTRANSCO), and replace it,

if required.

2.APTRANSCO to ensure that the distributed architecture employed

in implementing busbar protection at their Gooty 220 kV SS does not

introduce any unwarranted delays in transmitting the triggering

signals to the Central Unit.

APTRANSCO

Annexure-II

Page 1 of 33

63/II.2 Tripping of 400 kV K.V. Kota-Suryapet

line

01-03-2017 at

20.05 hrs

Line tripped on operation of over-voltage protection

at K.V Kota and Direct Trip was received at Suryapet

1. APTRANSCO to furnish (i) FIR & TR for tripping events as

per SRLDC provided formats; and (ii) DR & EL within 24-hrs of

occurrence of tripping event in line with IEGC Regulation 5.2

(r).

2. APTRANSCO to adopt new OVR gradings for KV Kota

feeders, and confirm the same.

APTRANSCO Status vide APTRANSCO mail dated on 28-06-2017:

1. FIR furnished & DR configured

Pending

63/II.16 Multiple Trippings at 220kV Vizag

Switching Station (VSS) of APTRANSCO

27-03-2017 at

10:16 hrs

Bus-2 bus bar protection operated at 220kV VSS

end, resulting in the tripping of all the elements

connected to bus-2

1. APTRANSCO to furnish a detailed report on the reasons for LBB/

BBP operation at 220 kV VSS for a fault on 220 kV Gangavaram

feeder and remedial action taken to prevent recurrence of such

events.

APTRANSCO Yet to be informed Pending

64/II/1 Tripping of 400/220KV 315MVA ICT-

1and 230kV elements at 400kV Vemagiri

substation of APTRANSCO

09-04-2017

at 12:31 hrs

Suspected mal-operation of Busbar protection had

caused tripping of 220kV Bus-1 at Vemagiri.

APTRANSCO to furnish a report on the remedial action taken along

with single line diagram of 400/220 kV Vemagiri SS indicating fault

location and CB's involved and protections operated.

APTRANSCO Yet to be informed Pending

64/II/2 Tripping of 400/220 kV ICT’s – 2 & 3 at

400 kV Ghani substation of APTRANSCO

10-04-2017

at 17:29 hrs

ICT’s – 2 & 3 got tripped due to operation of 220 kV

Bus-2 busbar protection at 400/220KV Ghani

substation.

APTRANSCO to furnish single line diagram of 400/ 220 kV Ghani SS

clearly indicating (i) bus-configuration, (ii) location of fault, (iii)

breakers involved and type of protections operated.


Single line diagram sent vide mail dated : 27.06.2017.

Pending

64/III/1 Tripping of 400 kV Uravakonda-

Jammalamadugu line-1

02-04-2017 at

17:58 hrs

R-phase to earth fault and line did not auto-reclose.

Fault clearing time - 500ms

For the line under consideration, APTRANSCO to check & ensure

healthiness of carrier protection and make Auto-Reclosure

functional.


Carrier aided protection scheme has been tested end to end and rectified the

problem.

Pending

64/III/5 Tripping of 400kV Krishnapatnam-

Nellore line-2

11-04-2017 at

2:41 hrs

Line tripped on Y-phase earth fault. Line auto-

reclosed at Krishnapatnam and did not auto-reclose

at Nellore-AP (Manubolu).

For the line under consideration, APTRANSCO to look into reasons

for A/R failure at Nellore-AP (Manubolu) end, and furnish a report

on the remedial action taken.


The ABB make REL 670 type main-2 distance relay seen the fault as R-

Y phase to phase fault. Hence A/R is not operated. For the similar incident

on 07.06.2017, the operation of A/R is successful.

Pending

64/III/6 Tripping of 400kV Krishnapatnam-

Nellore line-1

12-04-2017 at

2:51 hrs

Line tripped on Y-phase earth fault. Line auto-

reclosed at Krishnapatnam and did not auto-reclose

at Nellore-AP (Manubolu).



on the remedial action taken





Pending

64/III/10 Tripping of 400kV Krishnapatnam –

Nellore_AP line-1

13-04-2017 at

4:38hrs

Y-phase to earth fault. Line auto-reclosed from

Krishnapatnam end and did not auto-reclose from

Nellore-AP end



on the remedial action taken.





Pending

Tripping of 400 kV Khammam - KTPS

line-2

The issue was discussed in PCSC-58 meeting held on 18.10.2016, when

PCSC forum agreed to de-link the implementation of the Item from the

scope of Protection Audit Recommendations (PAR), and pursue it as part

of PCSC Recommendations.

TSGENCO mail dated 30-05-2017

Procurement of Differential Protection relays is under process and the

work will be completed by the end of November 2017.

TSGENCOProvision of line differential protection for Jurala line 1 & 2 (line length-1.45 KM) feeders at 220 kV Jurala HPS [Carry-Over from Protection Audit Recommendations]58 Pending

24-12-2016 at

10:52 hrs

Line tripped on B-phase to earth fault. First fault was

persistent for 380 ms. Auto-reclose was successful at

Khammam end during 1st fault. 2nd fault occurred

during re-claim time of breaker hence Khammam end

breakers also got tripped.

1. TSGENCO to implement the SRPC agreed philosophy for Power

Swing Blocking in all distance relays on the feeders emanating from

KTPS.

2. For the line under consideration, TSGENCO to consult relays

OEM to migrate to new versions of Firmware (from to 4.72.01) and

Pset (to 4.70.02).

line tripped on direct trip receive at Gajwel and was

holding from Hyderabad

06-10-2016 at

12:16 hrs

Pending

Telangana

TSGENCO TSGENCO mail dated 30.03.2017:

1. According to SRPC phylosphy power swing block settings are changed

to ALL ZONES BLOCK EXCEPT ZONE1.

---------- Completed

2. M/s. Siemens is requested to depute the service Engineer to update the

firm ware of existing SIPROTEC relays in 400KV switch yard. This work

will be completed on or before 15.04.2017. -------------- Pending

Pending61/III/5

63/III.2 02-03-2017 at

1:57 hrs

1. APTRANSCO to check and ensure correctness of A/R operation

for the lines emanating from their Nellore-AP (Manubolu) SS.

2. APTRANSCO to configure DR’s of line protection relays for a

post triggering period of 2 sec to capture complete A/R operation at

their Nellore-AP (Manubolu) SS.


1.The ABB make REL 670 type main-2 distance relay seen the fault as Y-

B phase to phase fault. Hence A/R is not operated. For the similar incident


Pending

Tripping of 400 kV Gaiwel-Hyderabad

line

59/IV/3 TSTRANSCO mail dated on 21-12-2016:

(i) Letter is been given to field for conducting end to end testing of 400kV

Gajwel-Ghanapur line.

(ii) Healthiness of PLCC system components will be checked while

conducting end to end testing.

TSTRANSCO


Nellore line-1

Line tripped on B-phase to earth fault and line auto-

reclosed from Krishnapatnam end but did not auto-

reclose from Nellore-AP end.

For the line under consideration, the following shall be carried out by

TSTRANSCO in coordination with PGCIL (SR-I):

(i) End-to-end communication for DT/ permissive & other signals

may be ensured by testing at both the ends.

(ii) Healthiness of PLCC system components (hardware and software)

at both ends shall be checked and faulty components shall be repaired/

replaced.

Annexure-II

Page 2 of 33

65/II/8 Tripping of 400/220 kV Hyderabad ICT-

4 and 220 kV lines at Hyderabad

substation

10-05-2017 at

2:39 hrs

Operation of busbar protection due to fault in 220 kV

Bus at 220kV Hyderabad Substation

TSTRANSCO to investigate the reasons for BBP operation for 220

kV Bus-2, and furnish a report on the remedial measures taken.

TSTRANSCO Yet to be informed Pending

PendingFor the line under consideration, TSTRANSCO to carry out the

following in coordination with TSGENCO:

(i) Healthiness of PLCC system components (hardware and software)


replaced.

(ii) End-to-end communication for DT/ permissive & other signals


(iii) Frequency bandwidth tuning of PLCC link for faithful

transmission of signals shall be carried out.

62/IV/5 Tripping of 400 kV Gajwel-

Bhoopalapalli line-1

16-02-2017

at 15:00 hrs

TSGENCO /

TSTRANSCO

TSTRANSCO mail dated on 31-05-2017:

1. Letter is been given to field for conducting end to end testing of 400kV

Gajwel-Bhoopalpalli-1 line.

Line tripped at Bhoopalapally on DT receive and was

holding from Gajwel.

TSTRANSCO mail dated on 31-05-2017:

1. Letter is been given to field for conducting end to end testing of 400kV

Gajwel-Ghanapur line.

replaced.

Annexure-II

Page 3 of 33

Karnataka

Annexure-II

Page 4 of 33

KPCL

38/GD/3.5 Pending

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.

Mail received on 07-07-2015 , 21-10-2015 and 23-11-2015:

1. Completed.

2. Completed.

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

reviewed.

Status received vide KPCL mail dated 14.06.2017:

1. Completed.

2. Completed.

3. Providing 2 separate DC sources is under process

Pending

Mail recieved on 28-05-2015:

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.


NIT floated on 5.5.15 through e-portal. Bid evaluation completed.

Obtaining of Administration approval to place P.O is in progress.

However, as per therecommendationsof PSAG-10, Relays

weretemporarilyrearranged.Testing & commissioning completed with the

assistanceofKPTCL.


NIT floated on 5.5.15 through e-portal. Bid evaluation completed. LOA's

issued to M/s Schneider Electric Infrastructure Ltd. on 08.10.2015.


LOA's issued to M/s Schneider Electric Infrastructure Ltd. on 08.10.2015.

Engineering work is in progress.

Status informed during Special Meeting held on 03.06.2016:

LOA’s issued to M/s Schneider on 08.10.2015. Inspection of relays

completed and received at site. DI issued for all balance materials except

furnitures.


Numerical Distance Protection relays commissioned on 12.04.2017

for all 4 lines at Kadra PH.

Installation, Testing and commissioning of Numerical Distance Protection

Relays for all the 4 outgoing lines is completed in all respect at Kodasalli

power house.

KPCL1. 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.

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

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.

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.

GD-1 at Kadra and Kodasalli hydro

power station

16-02-2015 at

12:56 hrs

GD-1 at 220kV Kadra power Station of

KPCL

41/I/1

Annexure-II

Page 5 of 33

49/II/15

54/II/4 Tripping of 400 kV Raichur TPS-

Mahboobnagar line

05-04-2016 at

10:23 hrs

Line tripped on operation of Backup impedance

protection of line reactor. Direct trip was received at

Mahboobnagar end.

KPCL to keep the functioning of the concerned electro-mechanical

back-up impedance protection relay under observation, and replace it

with a spare at the earliest.

KPCL Status received vide KPCL mail dated 10.07.2017:

The electro-mechanical back-up impedance protection relay is in service.

However, Budgetary offer obtained for the retrofitting of Line reactor

protection with Numerical relay and is under process

Pending

54/II/9

Pending

PendingStatus informed during Special Meeting held on 03.06.2016:

1. Hot line washing was done previously.tender process is on for silicon

coating of insulators.

Status received vide mail dated 10-07-2017:

1. Off line water washing is being carried out whenever the Unit or Line is

under shutdown. Silicon coating for Unit#8 main & tie breakers carried

out in Sep'16 and same is under observation. Till today in order and good

condition. For remaining breakers, since it is big order, approval for the

same is under process.

2. Static / Electromechanical relays are existing in all 1 to 7 units. Breaker

flash over protection feature will be enabled (if available) in the numerical

relays which will be retrofitted in phased manner during R&M works.

KPCL1. KPCL to carry out hot-line washing of RTPS-connected lines

regularly to avoid trippings due to fog and dust.

2. KPCL may see the feasibility of providing breaker flashover

protection at RTPS, and implement the same if possible.

54/I/4 220 kV Nagjheri - Bidnal line tripped on B-E fault at

12:28 Hrs. At the same time, five running generating

units (1, 2, 3, 4 & 6) at Nagjheri tripped on operation

of Generator Transformer’s back-up Over Current &

Earth Fault protection.

Pending

1. KPCL to revise the settings of GT’s back-up O/C and E/F

protections considering their individual contribution to solid bus fault

at 220 kV bus of Nagjheri PH.

2. KPCL to upload/ make available various tripping files

(FIR/DR/EL/TR) for all tripping involving their stations in

compliance of IEGC Regulation 5.2 (r).

14-04-2016 at

12:29 hrs

Tripping of Nagjheri Generators Pending

Trippings at 220kV Raichur TPS

KPCL

Running Unit-4, 5 and Unit-8 and 400kV RTPS-

Yeramaras TPS feeder got tripped due to de-

energization of both 400kV Bus-1&2 at Raichur TPS

12-11-2015 at

00:30 hrs

Y-ph Pole of Tie-breaker of Unit-4 at RTPS failed.

Unit-4 got tripped on operation of Generator

Differential, Reverse power & LBB protection.

Operation of LBB protection led to tripping of BUS-2

at RTPS

46/II/21


1. i) Silicon coating for Unit#8 main & tie breakers carried out in Sep'16

and same is under observation. Till today in order and good condition. For

remaining breakers, since it is big order, approval for the same is under

process. ii) Hot line

water washing stopped and off line water washing is carried out whenever

the 400 KV Unit or line is under tripped condition / Shutdown condition.

2. Static / Electromechanical relays are existing in all 1 to 7 units. Breaker

flash over protection feature will be enabled (if available) in the numerical

relays which will be retrofitted in phased manner during R&M works.

KPCL13-04-2016 at

21:12 hrs

1.KPCL to undertake the following remedial measures to avoid

breaker flashovers:

(i) Replacing all porcelain insulators with composite insulators

(ii) Carrying out hot-line water washing of all insulators on regular

basis.

(iii) Applying Room Temperature Vulcanizing (RTV) Silicone high

voltage insulator coatings to all bus-connected ceramic insulators of

equipment like CT, PT, CB, Isolators etc.

2.KPCL to take steps to provide dedicated breaker flashover

protection to all breakers at Raichur TPS at the earliest.

Tripping of 400kV Raichur TPS Bus-2


1) Anti-pumping contactors of all the nine 220KV Lines are in circuit and

tested periodically during AOH works of lines along with other protections.

2) Completed.

3) Possibility to use both the 220kV buses as main bus under normal

operation is under review.


1) Completed

3) Two bus operation for 220kV buses : In place of existing CT switching

relays, High speed manual heavy duty change over switch of sufficient

current capacity will be retrofitted to all feeders at 220kV station and same

will be operated manually during changeover of feeder by one bus to the

other and this arrangement may facilitate to put both buses in service. Time

required for this retrofit is around 90days . However, this work will be

taken up only after retrofitting of electromagnetic relays with numerical

relays for Main-2 protection of all 220kV lines, for which work is in

progress.


1) Completed.

2) Completed.

3) Two Bus operation for 220kV bus is being carried out whenever

required. However scheme for tripping of one bus during LBB/fault and

maintaining the other bus intact by tripping B/C breaker will be taken up in

R&M works.

KPCL1. KPCL to check the operation of anti-pumping relay on 220 kV side

and keep it in healthy condition.

2. KPCL to provide manual reset to the 220 kV side master trip relay.

3. KPCL to use both the 220 kV buses as main buses under normal

operation, and should go for single bus operation only during

emergencies.

07-06-2015 at

01:35 hrs

Trippings at Raichur TPS


1. GT backup overcurrent & earth fault settings are revised as per the

recommendations of our head office CEED,Bangalore, copy of letter

enclosed.

2. FIR/DR/EL/TR are being uploaded in the recent incidences as all the

main-2 relays are replaced with new numerical relays

Annexure-II

Page 6 of 33

55/II/1

56/I/2 Complete outage of 220kV Sedam

Substation of KPTCL.

19-06-2016 at

15:27hrs

220kV Sedam-Humnabad-2 tripped at Sedam on

Distance protection, Zone-2. Sedam-RTPS-1 &2 lines

tripped at RTPS end only. 220kV Tandoor inter-state

line was hand tripped due to incoming supply failure

KPCL to disable GFC protection on all lines emanating from their

generating stations.


As per the reccomndations of KPTCL in Feb'16 the settings are done with

a time delay of 2 secs.

Pending

57/II/3 Tripping of 400/220 kV ICT-2 at Raichur

TPS

07-07-2016 at

3:32 hrs

ICT-2 tripped on operation 400/220KV ICT-2 was

tripped on operation of 220KV side Instantaneous

over current protection during B-phase to earth fault

in 220kV RTPS-Sedam-II line.

KPCL to review appropriately the high-set of ICT’s back-up O/C

protection at their 220 kV RTPS so that they do not operate for a

normal through fault.


The settings will be reviewed in co-ordination with KPTCL & OEM.

Pending


1. On 09.09.2016 at STRP,Two units were running(Unit-3 & Unit-4.It is to

clarify that, Station tripped due to spurious operation.LBB relay in Unit-4

and not due to operation of Unit-3 LBB as indicated in PCSC

recommendations .Unit-3 which was in service tripped as a consequence of

LBB Protection.How ever, following actions performed in both Units.

a) Trip coil-1 and Trip coil-2 circuit (including cable from protection panel

KPCL

Pending06-09-2016

at 14:40 hrs

31-05-2016 at

17:21 hrs

Direct Trip was sent from YTPS to RTPS and BTPS

01-05-2016 at

21:44 Hrs

LBB of 220kV Kodasalli breaker at Kadra end got

operated which resulted in tripping of Bus at Kadra

and in turn led to tripping of all elements


1) Zero-sequence compensation feature is already enabled in all the

differential relays of transformers. ---Completed

2) Referred to OEM for the tripping of line on SOTF protection.

3) Action has been taken to retrofit the protection relays of tie bays of

Mahbubnagar and Munirabad line to enable Auto-reclosure function.

(i) KPCL to check settings of LBB protection in all relays from which

it was implemented, and ensure that their configuration, logic, and

timing are in order at their 220 kV Kadra PH.

(ii) KPCL to furnish details regarding the existing LT auxiliary

supply arrangement at their 220 kV Kadra PH, and take steps to

provide a suitable Auto-Main-Fail (AMF) panel for DG set to effect

its auto-starting in case of failure of LT supply.

(iii) KPCL to ensure time-sync of all relays (DR’s & EL’s) with GPS

at their 220 kV Kadra PH.

(iv) KPCL to provide stand-alone Event Logger at their 220 kV

Nagjheri PH.

KPCL

Pending


1. All logics checked and found normal. LBB timing checked and found

200msec as per KPTCL MRT recommendation. - Completed

2. Work Under Progress

3. New GPS System commissioned along with new numerical and

synchronised with GPS system - Complied

4. Work Under Progress


1. DEF settings in lines are made as per recommendations of CE(RT) &

R&D, KPTCL, Bangalore & EE(RT), KPTCL Hubli.

High set operation of DEF relays is disabled at Kodasalli end.

2. All these guidelines are incorporated by KPTCL during the replacement

of line protection relays.

3. New stand alone event logger is to be procured since spares for old stand

alone event logger are obsolete.

KPCL (i) KPCL to disable high-set operation of DEF relays

(ii) KPCL to block DEF relays whenever corresponding distance

protection relays pick up at Kodasally end on Nagjheri – Kodasalli

lines, and

(iii)KPCL to provide stand-alone Event Logger at their 220 kV

Nagjheri PH.

Bus dead occurred at 220kV Nagjheri PH due to

tripping of evacuating lines.

Pending

Tripping of 400kV Bellary TPS-

Yeramarus TPS line and

400kVYeramarus TPS - Raichur TPS

line

PendingYet to be informed55/II/19

Pending

31-08-2016 at

12:47hrs

(i) KPCL to ensure the integrity of the connecting cable/ conductor

from Generating Unit-3 to its corresponding GT breaker at their STR

PH.

(ii) KPCL to ensure the healthiness of Manual Current Regulator

(MCR) of Unit-3’s AVR at their STR PH.

(iii) KPCL to ensure the healthiness of AVR’s of all Units of STR

PH.

Spurious operation of LBB protection of line feeder

had led to tripping of 220 kV bus at Sharavathy Tail

Race power house.

9-09-2016 at

11:19 hrs

Complete outage of 220 kV Sharavathy

Tail Race PH

Pending

15-04-2016 at

15:36 hrs

KPCLDuring testing of retrofitted distance protection in

400kV Raichur-2 feeder, LBB protection trip DC got

extended to Bus trip. This resulted in tripping of

220kV bus at RTPS and all connected 220 kV

elements. Unit-4 which is connected to 400 kV Bus

got tripped due to tripping of Station Utility

Transformer that is connected 220 kV bus

1.KPCL to properly configure the distance relays at YTPS end on

both YTPS – BTPS line and YTPS-RTPS line with specific focus on

reaches and timings of Zone-2, Zone-3, and Zone-4 (reverse).

2.KPCL to ensure the healthiness of Direct Trip circuits and relay

coils at YTPS.

3.KPCL to ensure time sync of DR’s and EL’s at YTPS with GPS.

Triggering incident was failure of R-phase CT of

400/220kV ICT-1. 400kV YTPS-RTPS line got

tripped from YTPS end. 400kV RTPS-

Mehaboobnagar line tripped on a B-phase to earth

fault.

Complete outage of 220 kV Nagjheri PH

of KPCL.

Multiple tripping at 400 kV Raichur TPS

Station


Two Bus operation for 220kV bus is being carried out whenever required.

However scheme for tripping of one bus during LBB/fault and maintaining

the other bus intact by tripping B/C breaker will be taken up in R&M

works.

54/II/13

58/I/2 (GD)

58/I/5 (GD)

Complete outage of 220 kV Kadra power

station of KPCL

1.KPCL to enable zero-sequence compensation feature, if not already

done, in all differential relays of transformers at RTPS.

2.KPCL to examine in detail the reasons for SOTF operation at RTPS

end for the fault on RTPS-Veltoor line, and if required relay

(configuration) settings at RTPS end may be suitably got revised with

the help of their OEM.

3.KPCL to take steps to enable auto-reclose for the Tie-CB’s in the

dias containing Munirabad and Veltoor (Mehboobnagar) at RTPS.

58/I/3 (GD)

Tripping of Units at Raichur TPS In view of the availability of two buses along with healthy bus-

coupler at 220 kV RTPS, KPCL is recommended to put in service the

double-bus operation at 220 kV RTPS by suitably distributing loads

within 15 days.

Annexure-II

Page 7 of 33

a) Trip coil-1 and Trip coil-2 circuit (including cable from protection panel

to GCB Marshaling Box)of GT Breakers of Unit 03 and 04 checked found

ok.

b) Integrity of Connecting cable/conductor from Generating unit no.3 and

also to its corresponding GT Breakers inspected and found ok.

c) Regarding Spurious operation of Unit No.04 LBB relay and its

timer.Checked the operation of the LBB overcurrent relay with its external

Timer for repeated correct operations, it was found that LBB Timer was

giving correct timing operation for 1 in 3 operations only i.e. for one of the

operation it was operating within 40ms compare to set value(200ms) hence

declared as faulty and the same has been replaced with new one later

operation of the new Timer checked and found ok.operating for >200mse

only. With this cause for spurious operation of LBB and resulting in

complete outage of STRP has been identified and solved -----

Completed

2. In Unit -3,MCR is working satisfactorily.it is to clarify that problem was

existing in Unit No.4 AVR manual channel reference value of Generator

.The Same has been replaced with spare one. Manual channel AVR is

found to be Ok. ------Completed

3. All the units AVR's Healthyness checked and found Ok. -

-----

Completed

4. Presently at GPH,no stand alone Event logger exists. Since the subject

requirement pertains to all the Generating units and in view of

Standardization of the complete system, Networking of numerical relays

carried out and events are availble in networking system..

(i) KPCL to check and correct configuration settings of LBB

protection in all relays from which it was implemented, at their 220

kV Varahi PH.

(ii) KPCL to provide stand-alone Event Logger at their 220 kV STR

PH.

KPCLLBB protection operated and caused bus shut down at

Varahi PH

Pending

21-01-2017

at 00:38 hrs

12-09-2016 at

14:47 hrs

KPCL

Partial disturbance occurred in central Kerala grid due

to overloading and tripping of 220 kV lines. Loss of in-

feed to 220 kV Kalamassery, 220 kV Brahmapuram,

220 kV Ambalamugal, 220 Pallom & 220 kV Kochi

occurred. Generation at Neriamangalam, Panniar,

Chengulam and Pallivasal also got affected during the

incident.

(i) SLDC, KSEB to put in place proper mechanism to ensure adequate

load-generation balance is maintained in their control area at all

times, and due vigilance is exercised in operating an already depleted

transmission network.

(ii) KSEB to put UFR in service at New Pallom end on 220 kV New

Pallom – Amabalamugal line as part of Kudankulam Regional

Islanding Scheme.

KPCL

Status received vide mail dated 10.07.2017:

1. Furnishing FIR & TR of the tripping events as per the formats provided

by SRLDC.

4. Refered to OEM for the tripping of Tie CB of Munirabad line on SOTF

protection.

Pending


LBB Protection system is in Bus bar Protection Panel.The Configuration

settings are checked.They are as follows.

Minimum operating primary current is 160A

Stage I:Issue of Retrip to the feeder is 100ms after the action of main

distance protection Relay/initiation of LBB.

Stage II:Bus bar LBB Trip -200ms.

Total time of LBB trip is 300ms from the time of occurrence of Line Fault.

Disturbance in Kerala system Yet to be informed Pending

(i) KPCL to adopt the following VT fuse-fail logic for all 220 kV

lines emanating from NPH:

“Under VT fuse fail condition, distance protection shall normally be

kept blocked. However, upon detection of a fault (sensed by negative

sequence component), blocking of distance protection shall give rise

to operation of its inherent Over-Current protection set with a definite

time delay of 500 msec”.

(ii) KPTCL/ KPCL to revise Zone-2, Zone-3 and Zone-4 (reverse)

timings of DPR of all 220 kV lines emanating from Nagjheri PH in

line with Ramakrishna Committee guidelines.

Triggering event was the fault on 220 kV Nagjheri

–Kodasalli line-2. Both buses of 220 kV Nagjeri

power station of KPCL got

de-energized.

62/I/1 KPCL Status received vide mail dated 14.06.2017:

1. Already settings are discussed with EE(RT), Hubli and soon relays will

be tested for VT fuse fail condition.

2. Timings of Zones were set as per the recommendations of CE(RT) &

R&D, KPTCL, Bangalore & EE(RT), KPTCL, Hubli.Regarding revision

of timings will be carried out in coordination with EE(RT), KPTCL,

Hubli.

Pending

16- 03-2017 at

01:18 hrs

Bus-2 B-Ph differential bus bar protection operated

at 400 kV RTPS end, tripping all the main breakers

connected to Bus-2

1. KPCL to start furnishing FIR and TR of their tripping events as

per the formats provided by SRLDC.

2. KPCL to check earth-mat resistance for 400 kV switchyard and

ensure that it is within prescribed limits.

3. KPCL to set right operation of SER in C&I Control Room of Unit-

4.

4. KPCL to furnish action taken w.r.t. tripping of Tie-CB of

Munirabad line on SOTF protection. OEM report, in this regsrd, may

be furnished.

PH.

(iv) KPCL to provide stand-alone Event Logger at their 220 kV STR

PH.

15-09-2016 at

14:06 hrs

63/II.10 Multiple trippings at 400 kV RTPS

substation of KPCL

58/I/7 (GD) Complete outage at Varahi Hydro Power

Station

58/I/6 (GD)

Complete outage of 220 kV Nagjheri

substation of KPCL

Annexure-II

Page 8 of 33

65/II/9 Tripping of 400/220 kV ICT-1 at BTPS 13-05-2017 at

19:41 hrs

ICT-1 got tripped on operation of LV side earth fault

protection during R-phase to earth fault in 220 kV

BTPS-Lingapur line

1. KPCL to review the need for providing separate non-directional

sensitive earth fault protection for ICT’s at their BTPS station, and

take steps to disable the same.

2. For 220 kV BTPS –Lingapura line, KPCL to resolve issues relating

to PLCC carrier communication, and put A/R into service.

KPCL Yet to be informed Pending

65/III/2 Tripping of 400 kV Hiryur-BTPS line-1 06-05-2017

at 14:01 hrs

Y-phase to earth fault had occurred in line. Direct

trip was sent from BTPS to Hiryur end.

KPCL to introduce suitable delay (say, 3 sec) for UVR tripping, and

disable sending of DT to the other end on UVR operation at their

BTPS station.

KPCL Yet to be informed Pending

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.

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.

PendingMail 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.

2. Completed.

3. Completed.

KPTCL Mail recieved on 23-01-2016:

1. Existing back up relays will be replaced by Main-2 protection. LOI

issued M/s Alstom for taking up the works.

KPTCL Mail Recieved dated 25-05-2016:

Under the Scope of R&U. The work will be taken up by M/s Alstom

shortly.


1. ALSTOM make P442 type Numerical relays are supplied to the site,

replacement of M-1 relays(OPTIMHO) by new relays will be taken up

shortly

KPTCL25-10-201438/GD/3.1 GD-1 at Mahalingapura Substation of

KPTCL

66/ III/ 1 For the line under consideration, KPCL to carry out the following:





replaced.

R-phase to earth fault had occurred in line. Line did

not auto-reclose from both ends.

05-06-2017 at

19:48 hrs

Tripping of 400 kV BTPS-YTPS line KPCL Yet to be informed Pending

Annexure-II

Page 9 of 33

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

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

R&M works.

2. O&M personnel are instructed to take sufficient care in order to avoid

unwarrented trippings. --- Completed.

KPTCL mail received on 23-01-2016:

1. New C&R panels(with numerical relays) erected for 500MVA ICT-1

&2 under R&M work, which will be commissioned shortly.


1. New C&R panels(with numerical relays) erected for 500MVA ICT-1

&2 under R&M work, which will be commissioned shortly.


1. New CRPs mounted in bay KIOSK commissioned under R&M works.

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.

40/I/1

220kV Sedam-

Tandur line

Line tripped on Yphase to earth fault from both the

ends

20-12-2014

at 22:20 hrs

Pending

KPTCL Pending

39/I/5 Tripping of 400/220kV

ICT-2 at Hoody

substation of KPTCL

Suspected mal-operation of 220kV side Rphase

over current relay

01-12-2014

40/IV/1 Pending

KPTCL1. 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.

1. 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.

22-12-2014 at

21:22 hrs


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.

---- Completed


1. 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.

KPTCL mail recieved on 23-01-2016:

1. Bus-II PTs yet to be commissioned.Planned to complete before end of

April-2016.


1. Yet to be attended

GD-1 at 220kV Ambewadi Station of

KPTCL

KPTCL was requested to explore the possibility of providing A/R

feature to this line and submit the remedial measures to the PCSC

forum.


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

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


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

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


SEE,SCADA to update the latest status


Action is being taken to restore carrier protection.AR will be enabled once

carrier signal is restored.

KPTCL

Annexure-II

Page 10 of 33

Pending

PendingKPTCL

Complete outage of 220kV Ambewadi

substation of KPTCL

42/I/2 (GD)

27-09-2015 at

4:23:17 hrs

Fault in 220kV Ambewadi-Nagjheri line-2

KPTCL

KPTCL

48/I/2 (GD) All connected 220kV lines and transformers were

taken on 220kV North bus as South bus was under

shut down for conversion of strung bus to rigid bus

and isolator replacement under R&M works. Failure

of HV side Y phase CT of 150MVA Transformer-3

occurred at Peenya Substation which resulted in

operation of Differential and HV REF protection. The

failure of CT also resulted in a 220kV bus fault in

North Bus.

42/I/1 (GD)

41/I/4

Complete outage of 220kV Sedam

substation of KPTCL

15-02-2015 at

14:24 hrs

Complete outage of 220kV Peenya

Substation in Karnataka

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.

KPTCL


1. Bus Bar protection will be provded under R&U.

2. A/R yet to be enabled.


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.

KPTCL to revise distance relay settings at Nelamangala end for 220

kV Nelamangala – Hebbal - Peenya line – 1 for the effective line

length of 17 km. These new settings can be appropriately reviewed as

and when the tie-arrangement at Hebbal is done away with.

1. 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.


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


Tandoor line. AR will be enabled.



stage.




1. Bus bar protection panels pocured and erected at Sedam. Wiring ,

testing ,commissioning is being taken up.Planned to complete by April

2016.



Pending


Presentl 220kV Nelamangala -Hoody(i.e. nelamangala-Peenya-Hebbal -

Hoody line is made LIILO at Yelahanka sub station and breaker at

Peenya is kept open, necessary modification in distance relay settings

adopted for new configuration.

Pending

PendingKPTCL mail received on 23-01-2016:

Will be complied in a months time.

30-09-2015 at

10:41 hrs

Outage of 220kV Ambewadi station in

Karnataka

12-03-2015 at

7:51 hrs

Fault occurred in 220kV Sedam-Shahpur line

48/I/3 (GD) KPTCL to fast-track providing A/R on all 220 kV lines emanating

from Ambewadi SS to prevent Station shut-down on temporary faults.

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.

KPTCL to activate non-directional Over Current protection with a

time delay of 600-800 msec for Fuse

failure condition at Lingasugur.

KPTCL Status received vide KPCL mail dated 10.07.2017:

LV earth fault relay had an additional default E/f setting having a definite

time which resulted in tripping of ICT-2 and the same was rectified and

already complied.

Pending

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.

Tripping of Unit-1&2

along with 400/220kV

ICT-2 at Raichur TPS

Complete outage at 220kV Sedam

Substation of KPTCL (GD-1)

220kV Ambewadi-Nagjheri line-2 tripped on B-phase

to earth fault. This resulted in loss of supply to 220kV

Ambewadi bus. 220kV Ambewadi-Ponda line-1&2

were hand tripped after deenergization of bus at

Ambewadi.

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.

27-01-2015 at

8.00 hrs



stage.



47/II/13

Annexure-II

Page 11 of 33

52/I/3 (GD) Complete outage of 220kV Shimoga

substation

22-02-2016 at

15:03 hrs

220kV Bus Bar protection operated during failure of

R phase CT in DVG-2 line bay.

KPTCL to operate 220 kV Shimoga on multi-bus operation under

normal conditions, put it on single-bus operation only under

emergency conditions.

KPTCL KPTCL Mail received dated 25-04-2017:

Replacement of existing BBP by new BBP with 4 zone protection is being

taken up under R&U.

Pending

56/II/6 Tripping of 220kV Ambewadi-Ponda

(Xeldam) line-1

10-06-2016 at

13:33 hrs

Line tripped on Y-E faut due to DPR, Z1 operation KPTCL to keep A/R for Ambewadi – Ponda (Xeldam) line-1 in

service with immediate effect.

KPTCL Yet to be informed Pending

59/II/13 Tripping of 220 kV Bidadi (PG) - Bidadi

lines - 1&2

02-10-2016 at

10:32 hrs

Line-2 tripped in DPR, Zone-2 and Line-1 tripped on

operation of E/F protection from Bidadi end.

KPTCL to resolve PLCC carrier communication issues on 220 kV

Bidadi – Bidadi-PG D/C lines, and subsequently restore Zone-2

timing to normal values.


53/I/1

1.KPTCL to take steps to provide busbar protection at their 220 kV

Chikkodi inter-regional substation, and furnish a time-line for the

same.

2.KPTCL to review distance protection settings for 220 kV Chikkodi

– Kudachi line.

3.KPTCL to furnish equipment failure report of the current incident to

PSE&TD Division of CEA with a copy marked to SRPC.

Yet to be informedKPTCL

KPTCL Mail received dated 25-05-2016:

SEE, RTC, Bangalore to update the status


Providing numerical bus bar protection to 400kV buses and GPS time

synchronising equipment at Guttur is considered under R&U. Work is

awarded to M/s Alstom, execution will be taken up shortly.


GPS and accessories will be supplied during May 2017, expected to

complete the work within a month after supply of materials


KPTCL in coordination with

PGCIL (SR-II):





replaced.

KPTCL

KPTCL

Yet to be informed

KPTCL

Line tripped at Hiryur end due to direct trip receive

and was holding from Guttur


SEE, RTC, Bangalore to update the status

Multiple tripping at 400kV Guttur sub-

station

17-01-2016 at

18:53 hrs

49/I/1.3 (GD) 1. KPCL to provide A/R on all 220 kV lines emanating from Nagjheri

PH.

2. KPTCL to provide A/R on all 220 kV lines emanating from

Ambewadi SS.

Failure of Lightning Arrestor of Y-phase Line Reactor

of 400kV Guttur-Hiriyur line-1 and line tripped on

distance protection Zone-1. Bus-bar protection of

400kV Bus-2 at Guttur substation also got operated

during the event sensing this through fault. 400/220

kV ICT-1 & 2 at Guttur, 400kV Kaiga-Guttur-2,

400kV

Guttur-Narendra-2, 400kV Guttur-Hiriyur-2 and

400kV Guttur-Munirabad which are on 400kV Bus-2

got tripped during the incident. 400kV Guttur-

Narendra-1 which was on Bus-1 also tripped at the

same time.

220kV Peenya-Nelamangala-3 tripped on B-E fault at

both ends. At the same time, 220kV Peenya-

Nelamangala-4 tripped on R-Y fault only at

Nelamangala end, and was in service from Peenya

end. Due to tripping of these two lines, 220kV Peenya-

Nelamangala-2 tripped on overcurrent protection.

KPTCL to furnish a report on the tripping of 220 kV Peenya-

Nelamangala line-4 Nelamangala detailing the remedial measures

taken including the settings adopted for Z1B (Zone extension) and

Power Swing Block.

Pending220kV Nagjheri-Ambewadi line-1 tripped at 13:33

hrs due to B phase to earth fault. Ambewadi was

radially fed from Nagjheri power station through

220kV Nagjheri-Ambewadi line-2. Tripping of this

line caused 220kV Bus shut down at Ambewadi and

remaining lines and transformers were hand tripped

Pending

Pending

Pending 1. KPTCL to configure all DR’s and EL’s at 400 kV Guttur SS so

that they will also get triggered for BBP operation.

2. KPTCL to ensure time-synchronization of all DR’s and EL’s with

GPS at their 400 kV Guttur SS.

KPTCL

Triggering incident was failure of B-ph PT of 220kV

Bus-2 (western bus) at 220KV Chikkodi substation.

220KV Chikodi- Belgaum-I line tripped on DEFR

(Inst), 220KV Chikkodi-Kudachi line tripped on

Distance protection and also 100MVA transformer-2

tripped on E/F protection.

Tripping of 400 kV Guttur-Hiryur line-1 10-10-2016 at

3:15 hrs


Substation of KPTCL

29.10.2015 at

14:34 hrs

Complete outage of 220kV Peenya

Substation of KPTCL

01-07-2016 at

03:03 hrs

Tripping of 220 kV Chikkodi-Mudshingi

and 220 kV Chikkodi-Talandage lines

51/II/21

16-03-2016 at

11:39 Hrs

57/II/1

59/IV/4 Yet to be informed Pending

Annexure-II

Page 12 of 33

62/II/3 Tripping of 220 kV Bus 2 and connected

elements (220kV HAL #1 and 2, 400/220

kV ICT- 1, 2 and 220/66 kV ICT-2) at

400/220 kV Hoody substation of KPTCL

(Load loss : 590 MW)

09-01-2017 at

23:06 hrs

Failure of R-phase CT of 220/ 66 kV transformer-2 at

220kV Hoody end resulted in a bus fault in 220kV

Bus-2. Fault was cleared by backup protection of

ICT's (220kV lines were being radially operated) due

to absence of busbar protection

1. KPTCL to provide Busbar protection at their 220 kV Hoody SS at

the earliest.

2. KPTCL to furnish an Equipment Failure Report on CT failure to

CEA with a copy marked to SRPC.

KPTCL KPTCL mail received dated 25.04.2017:

Numerical BBP is being provided under R&M works

Pending

64/II/9 Tripping of 400/ 220 kV ICT-2 and 3 at

Hoody substation of KPTCL

26-04-2017 at

15:40 hrs

ICT-2 tripped on suspected mal-operation Oil surge

relay of B-phase Transformer. ICT-3 tripped due to

overloading.

KPTCL to put in place a suitable SPS at their 400/ 220 kV Hoody SS

that takes care of over-loading of the other ICT when one ICT out of

ICT’s – 2 & 3 trips at the earliest, and furnish the details of

implemented SPS to PCSC forum.


65/II/17 Tripping of 400/220 kV ICT - 1 & 3 at

Hoody substation of KPTCL

(Load Loss: 750 MW)

26-05-2017 at

12:30 hrs

R phase limb of ICT-1 bank pre-close supervision

contact of trip coil -2 had arc over. ICT-3 got tripped

on over-loading

KPTCL to furnish compliance report on the recommendations given

in PSAG-18 meeting to PCSC forum.



station of KPTCL and 220kV Nagjheri

of KPCL

Complete outage of 220kV Nagjheri

power station and 220kV Ambewadi

substation of KPTCL

51/I/3

KPCL/KPTCL

KPTCL Pending

ICT-3 tripped due to operation of back-up earth fault

protection during fault in 220kV RTPS-Raichur line-

1.

KPCL/ KPTCL to check the ICT’s back-up (high-set) protection

settings, and ensure that they operate with a time delay of 100 msec.

KPCL/ KPTCL

Yet to be informed

Ambewadi Narendra line-2 tripped on fault and

220kV ambewadi Narendra line-1 tripped due to over-

loading. Running Units at Nagjheri also tripped during

the event due to tripping of evacuating lines

PendingStatus informed during Special Meeting held on 03.06.2016:

1. KPTCL informed that the matter had been taken up with concerned Line

Operation and Maintenance wing to carry out corridor clearance and

maintenance as per schedule to avoid frequent line faults in this corridor. A

letter had also been addressed to Chief Engineer, Bhagalkot zone, to ensure

lines in & around Kali complex are maintained in healthy condition. ---

Completed

2. KPTCL assurd that the final modified SPS would be implemented at

Nagjheri PH at the earliest. ------ Pending

3. KPCL informed that Nagjhari- Kodasalli Lines 1 & 2 had been kept in

service since 23.05.2016 @ 08.06hrs. ---- Completed


Modifications to be carried in Nagzari SPS logic is submitted to

SRLDC/SRPC for verification and approval


1. Will be reviewed in consultation with EE(RT), KPTCL, Hubli.

2. Both the lines are in charged condition.

KPTCL mail received dated 25.04.2017:

Numerical BBP is being provided under R&M works

KPTCL to provide numerical Busbar Protection at their 220 kV

Somanahalli SS at the earliest.

Tripping of 400 kV Neelamangala-

Hoody line-1

KPTCL to carry out the following for the line under consideration:

(i) Healthiness of PLCC system components (hardware and software)


replaced.

(ii) End-to-end communication for DT/ permissive & other signals


PendingTripping of 220 kV South Bus and

connected elements (220kV HSR, 220kV

Nagnathpura, 220 kV Harohalli, 220 kV

Subramanyapura, 220 kV Tataguni, 220

kV Mallur and 400/220kV ICT-2 and 3)

at 400/220kV Somanhalli substation of

KPTCL

(Load loss: 850 MW)

20-01-2017 at

14:34 hrs

Triggering incident was fault in 66 kV Somanahalli -

Bannerghatta line and fault was cleared by operation

of Back-up OCR at Somanahalli end.

15-02-2017

at 13:44 hrs

Line tripped at Hoody end on direct trip receive and

was holding from Neelamangala end.

Tripping of ICT-3 at Raichur Substation Pending

1. KPCL to furnish a report on the reasons for Unit-6 tripping at

Nagjheri PH.

2. KPCL/ KPTCL to modify suitably the SPS at Nagjheri Power

House such that it would also factor in the over loading of Ambewadi-

Narendra lines.

3. KPCL to put 220 kV Kodasalli - Nagjheri D/C lines into service if

more than 200 MW generation from Kali Complex (with Nagheri

Contribution not less than 50 MW) is ensured on sustained basis.

Pending

15-03-2016 at

12:28 hrs


Modifications to be carried in Nagzari SPS logic is submitted to

SRLDC/SRPC for verification and approval


1. Tripped since there was evacuation problem and there were only two

lines NA-1 and NA-2

2. Will be reviewed in consultation with EE(RT), KPTCL, Hubli.

3. Both the lines are in charged condition.


SEE,SCADA to update the status of healthiness of carrier protection of

220kV RTPS-Raichur 1 &2 lines


Details sought from KPCL for review of ICT's back up (high set) proection

settings as suggested. KPCL is yet to furnish the details required to give

53/I/3 (GD)

62/IV/4

62/II/5

18-03-2016 at

14:40 hrs

22-02-2016 at

12:36 hrs

KPCL/ KPTCL 1. To avoid tripping of transmission lines on transient faults, KPCL/

KPTCL 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).

2. KPCL/ KPTCL to review operation of SPS at NPH for

functionality (reduction of generation with tripping of evacuating

lines) and healthiness.

3. KPCL to put 220 kV Kodasalli - Nagjheri D/C lines into service if

more than 200 MW generation from Kali Complex (with Nagheri

Contribution not less than 50 MW) is ensured on sustained basis.

220kV lines from Nagjheri power house started

tripping from 11:00 hrs due to fault in lines. The

sequence of tripping is shown in SOE list. At 12:33

hrs, 220kV Narendra-Ambewadi lines-1&2 got

tripped which resulted in loss of evacuation path to

Nagjheri station resulting in tripping of running Units

and complete outage at Nagjhheri power station.

220kV Ambewadi station also got de-energized due to

tripping of source feeders i.e. 220kV Narendra-

Ambewadi-1&2 and 220kV Nagjheri-Ambewadi-

1&2.

53/II/1

KPTCL

Annexure-II

Page 13 of 33

56/I/3 Complete outage of 220kV Ambewadi


24-06-2016 at

20:57hrs

B phase to earth fault had occurred in 220 kV

Ambewadi-Ponda line-2. Fault was cleared by

tripping of feeders from remote end

1.KPCL & KPTCL to furnish an action taken report on the

recommendations given by PSAG-16 to PCSC forum.

2.KPTCL to keep A/R for Ambewadi – Ponda line-2 in non-auto

mode (i.e., only 3-ph trip should get extended on occurrence of a fault)

till the line is closed from Ponda end.

KPCL/KPTCL Yet to be informed Pending

TANTRANSCO mail dated 12.04.2017:

1. The recommendation will be ensured. AR logic will be configured in

Distance Protection relay itself instead of BCU. OEM has been addressed.

2. Post triggering period of 2 sec. to cover AR operation in DR time scale

will be provided.

TANTRANSCO mail dated 01.06.2017 & 15.06.2017:



Main-1 & 2 relays will be replaced for the requirement of more output

contacts for AR logic implementation.


is being provided.

TANTRANSCO mail dated 04.08.2017:



Main-1 & 2 relays will be replaced for the requirement of more output

contacts for AR logic implementation.


is provided. ----- Completed

TANGEDCO1. TANGEDCO to take properly configure A/R logic at NCTPS-II in

that in case of unsuccessful auto-reclsoure, three-phase trip shall be

given along with A/R block.

2. TANGEDCO to configure all protection relays DR’s time scale at

NCTPS-II for a post-triggering period of 2 sec to capture events such

as complete A/R operation.

R-phase to earth fault due to de-capping of insulator.

Auto-reclose attempt was unsuccessful.

22-02-2017 at

06:16 hrs

Tripping of 400 kV NCTPS-S.V.Chatram

line-2

62/V/3

Pending

Pending

Tripping of running Units & 230kV

feeders at Tuticorin TPS of TANGEDCO

(Gen Loss: 640 MW)

62/II/7 TANGEDCO

TANTRANSCO TANTRANSCO vide their mail dated 24.06.15 informed that different

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

Mail recieved on 24-07-2015 ,19-02-2016 and 24-03-2016:

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


TANTRANSCO: Not feasible in the existing SAS sub stations. Hence,

exemption may be given for these sub stations.

Mail received on 20-05-2016 ,16-06-2016,25-07-2016 & 24-09-2016 :

As discussed in the 52nd PCSC meeting, Swapping of Relays between two

stations is not feasible in the existing SAS sub stations. Hence, exemption

may be given for these sub stations.

Status received vide mails received on 10-11-2016 & 20.12.2016 &

12.04.2017 & 01.06.2017 & 15.06.2017 & 04.08.2017:

Different make Relays will be ensured for Main-I & II relays at Alamathy

TANGEDCO mail dated 15.04.2017:

1) New Relay is tested and ready for replacement.Now all 5 units are in

service.The relay will be replaced when lesser units are in service. ---

Pending

2.a)Steps are taken to renovate & mordernization of all the control panel

into Numerical based control panels. --- Pending

2.b) Since 230 KV indoor switchyard has no spare space providing dual

CT`s is not fessible. -- Completed

3) Procurement of EL & DR is under progress. --- Pending

TANGEDCO mail dated 26.04.2017:

1) Check zone New Relay is replaced on 17.04.2017 -- Completed.

2. Pending

3. Pending

settings as suggested. KPCL is yet to furnish the details required to give

the revised settings.


As requested by EEE (protection), CEERT, KPTCL, the details were sent

to through e-mail dtd. 08.08.2016. After receipt of reply from KPTCL will

be implemented accordingly.

Tamil Nadu

1. TANGEDCO to replace existing Check-Zone relay with a new one

possessing required performance.

2. TANGEDCO to take steps to provide numerical busbar protection

at their 220 kV Tuticorin TPS. TANGEDCO may also explore

providing dual CT’s (on either side) for all B/S breaakers at the time

of commissioning of numerical BBP, if there were no space

constraints.

3. TANGEDCO to take steps to provide for standalone Event Logger

(EL) and standalone Disturbance Recorder (DR) with automatic

downloading facility to a centralized server.

Failure of Bus Section-I Y-ph CT resulted in

operation of bus-bar protection for Bus Sections -I &

II. Running Units#1, 4 and 5, 230 kV Kayathar,

230kV Kudankulam, 230kV Sterlite, Station

Transformer-1, 2 & 3 got tripped during the incident.

Unit – 2 & 3 were not in service.

25-01-2017 at

22:36 hrs

Pending

29-03-2015 at

15:29 hrs

43/II/5 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.

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.

Tripping of 400kV

Alamathy-

SVChatram line-1&2

and 400/230kV ICT

at S.V.Chatram

Annexure-II

Page 14 of 33

05-09-2015 at

14:04 hrs

TANTRANSCO to take suitable measures like installing more stub-

towers along 230 kV OK Mandapam – Myvady line to avoid

excessive sag due to over-loading.

TANTRANSCO48/I/1 (GD) PendingComplete outage of 230kV Palladam, 230 kV

Othakalmandapam S/s, 230 kV Coimbatore S/s, 230

kV Thudialur and 230 kV Sadayapalayam S/s

Disturbance in 220kV Tamilnadu system

Different make Relays will be ensured for Main-I & II relays at Alamathy

end.

TANTRANSCO Mail received on 19-02-2016, 24-03-2016 and 27-04-

2016:

230kV Othakalmandapam - Myvadi feeder will be made LILO at Kongal

Nagar. Line restringing will be carried out along with the above proposal.

Mail Received on 20-05-2016 ,16-06-2016,25-07-2016 & 24-09-2016:




12.04.2017 & 01.06.2017 & 15-06-2017 & 04.08.2017:



Annexure-II

Page 15 of 33

51/I/1 (GD)

12-05-2016 at

12:15 hrs

55/I/1 (GD)

TANTRANSCO mail received on 24-03-2016:

CMR relay for extending LBB protection was released and LBB extended

from Distance Protection relay directly. CT is not available in the Bus

Coupler bay for zone segregation. However, during commissioning of third

ICT, Bus section Breaker will be provided for zone segregation. Numerical

BBP relay will be provided.

Status received vide mails recieved on 27-04-2016 and 20-05-2016 ,16-

06-2016, 25-07-2016, 24-09-2016,10-11-2016 & 20.12.2016 &

12.04.2017 & 01.06.2017 & 15-06-2017:

CT is not available in the Bus Coupler bay for zone segregation. However,

during commissioning of third ICT, Bus section Breaker will be provided

for zone segregation. Numerical BBP relay will be provided.


Contract awarded for providing third ICT & Bus modification works to

accomodate bus coupler bay. Numerical BBP relay has been provided and

tesing under progress.

Pending

TANTRANSCO

TANTRANSCODifferent type and Make of distance protection relays to be provided for Main-I & Main-II protection for 230kV feeders at 400 kV Sunguvarchathiram & 230 kV Sunguvarchathiram

Substation [Carry-Over from Protection Audit Recommendations]

Mail recieved on 25-07-2016 & 24-09-2016:

TANTRANSCO: Auto Transformer-2 HV side Bus isolator 'C'-phase

support insulator of 230kV Southern Bus was replaced and Bus Bar

Protection scheme was restored on 12.05.2016.


12.04.2017 & 01.06.2017 & 15-06-2017 & 04.08.2017:

CT is not available in the Bus Coupler bay for zone segregation. CT latch

relay is to be provided for all bays for zone segregation.

Complete outage of 230kV Madurai S/s

(Chekanaurani) of TANTRANSCO

Pending

TANTRANSCO 1. TANTRANSCO to provide split-bus operation with bus

sectionalizer CB for their 230 kV Madurai (Chekanurani) SS.

2. TANTRANSCO to provide two main-zone operation for the

numerical BBP that is being commissioned.

3. TANTRANSCO to examine the feasibility of providing Re-Trip

feature for the LBB protection, and accordingly take steps for

implementing the same.

Fault had occurred in 230kV Madurai-Sembatty line.

Trip from distance relay was not extended to breaker

due to protection DC fail. LBB protection got

operated resulting in a busbar trip at 230kV Madurai

substation. All elements got tripped as there is a

single bus operation at 230kV Madurai S/s

19-01-2016 at

11:56 hrs

Complete outage of 230 kV

Gummidipoondi Station of

TANTRANSCO

Flashover of Auto Transformer- 2 HV

B-phase Isolator supporting insulator of 230kV

Southern Bus occurred at Gummidipoondi station. At

the time of fault, Bus bar protection relay was not in

service for pre-commissioning testing of Auto

Transformer-2. All feeders got tripped due to

operation of zone-2 protection from remote ends.

The issue was discussed in PCSC-58 meeting held on 18.10.2016, when

PCSC forum agreed to de-link the implementation of the Item from the

scope of Protection Audit Recommendations (PAR), and pursue it as part

of PCSC Recommendations.

Status received vide mails dated 10.01.2017 & 12.04.2017 &

01.06.2017 &15-06-2017 & 04.08.2017:

Different make Relays will be provided for Main-I & II relays at

Sunguvarchatram end in a phased manner.

TANTRANSCO

58

TANTRANSCO Mail received on 19-02-2016 and 24-03-2016:

Revision of Bus Bar Protection setting was carried out. The stabilizing

voltage setting was raised from 410 to 450 volts. After completing the

necessary test, the bus bar protection put in to service on 29.12.2015.

Mail Received on 27-04-2016 ,16-06-2016,25-07-2016 & 24-09-2016:

Revision of Bus Bar Protection setting was carried out. After completing

the necessary test, the bus bar protection put in to service on 29.12.2015.

Mail received on 10-11-2016 & 20.12.2016:

Provision of Bus Coupler bay arrangement was included in the

Upgradation works proposed and the same was sanctioned by MoP through

PSDF.

Numerical relay allotted and being commissioned.


Numerical BBP relay was commissioned on 02.02.2017

Status received vide mail dated 12.04.2017 & 01.06.2017 & 15-06-

2017:

Numerical BBP relay was commissioned on 02.02.2017.

Provision of Bus Coupler bay arrangement was included in the

Upgradation works proposed and the same was sanctioned by MoP through

PSDF.


Numerical BBP relay was commissioned on 02.02.2017.

Provision of CT in Bus Coupler bay is arranged and zone segregation will

be provided.

Pending

Pending

TANTRANSCO to take steps to provide double-bus operation at

their 230 kV Gummidipoondi SS.

1. TANTRANSCO to examine the feasibility of providing two main-

zone operation for bus bar protection by exploring various alternatives

like replacing existing bus-coupler CB with a hybrid bus-coupler CB

that comes with inbuilt CT, replacing existing BBP relay with another

suitable relay that supports two main-zone operation, and implement

the same.

Busbar protection got operated for a fault in 230kV

Mywadi-Anaikadavu line

21-12-2015 at

6:28 hrs

Complete outage of 230kV Mywadi

station of TANTRANSCO

50/I/3 (GD)

Annexure-II

Page 16 of 33

14-09-2016 at

11:13Hrs

Bus Bar Protection (Zone-2) of 230 kV Bus-B got

operated at Alamathy Station during fault in 230 kV

Alamathy-Korattur feeder.

58/II/17 Mail received on 10-11-2016 & 20.12.2016:

1. The Bus Bar Protection scheme will be tested for healthiness including

the CT circuits.

2. High impedance BBP relay will be replaced by Numerical relay.

Status received vide mails dated 10.01.2017 & 12.04.2017 &

01.06.2017 & 15-06-2017:

1. The Bus Bar Protection scheme was tested for healthiness including the

CT circuits. AREVA make CTs in Alamathy SS are having different

kneepoint voltage for the cores. CT cores of higher knee point voltage has

been choosen for BBP in 230kV Korattur, 230kV OPG-1 & 230kV OPG-2

feeders on 29.11.2016. ---- Completed.

2. High impedance BBP relay will be replaced by Numerical relay. ---

TANTRANSCO Pending1. TANTRANSCO to check the healthiness of BBP relay by

conducting stability test, and take appropriate remedial action like

increasing voltage settings, ensuring the healthiness of CT’s, using

CT’s with similar characteristics (equal saturation effects & equal

winding resistances) etc. at their 230 kV Alamathy SS.

2. TANTRANSCO to replace the existing high-impedance BBP relay

with its low-impedance/ numerical variant so as to accommodate

variation in CT characteristics at their 230 kV Alamathy SS.

Bus Bar Protection (Zone1) of 230kV Bus-A got

operated at Alamathy Station during fault in 230 kV

Alamathy-OPG-1 feeder.

15-09-2016 at

22:14 hrs

Multiple tripping at 230 kV Alamathy

Station

Annexure-II

Page 17 of 33

64/1/4 Complete outage of North Chennai TPS

STG-1

26-03-2017

at 23:14hrs

Tripping of evacuating lines due to fault led to

tripping of running Unit at NCTPS Stg-1

1. TANTRANSCO to take steps to complete insulator replacement

works on the 230 kV lines owned by them in NCTPS area within 6

months.

2. TANTRANSCO to take steps to implement A/R on all 230 kV lines

emanating from NCTPS-I at the earliest.

TANTRANSCO Status received vide mails dated 04.08.2017:

1. All the Porcelain insulators were replaced with Polymer insulators in

230kV NCTPS-I - Tondiarpet feeders - 1 & 2.

2. AR will be implemented on all 230kV lines emanating from NCTPS-I.

Pending

65/II/1 Tripping of 220 kV Idukki –Udumalpet

line

05-05-2017 at

17.02 hrs

Line tripped due to B-N and R-N fault in line 1. TANTANSCO to correctly configure A/R logic at Udumalpet so

that in the event of 3-ph trip being given during A/R dead-time, the

relay will not try for auto-reclosure.

2. TANTRANSCO to keep A/R dead-time as 1 sec for all 220 kV &

above transmission lines.

TANTRANSCO Status received vide mails dated 04.08.2017:

1. AR logic configuration will be checked for correct operation.

2. In all the 400kV feeders, AR dead time is kept at 1 sec. The same will

be implemented in all 230kV feeders.

Pending

2. High impedance BBP relay will be replaced by Numerical relay. ---

Pending,

Status received vide mails dated 04.08.2017

1. Completed

2. High impedance BBP relay will be replaced by Numerical relay.

66/I/1 Complete outage of 230 kV Kadaperi

Substation of TANTRANSCO.

21-06-2017 at

17:43 hrs

230kV Kadaperi –Sriperumpudur Line-1, 230 kV

Kadaperi – Kalivanthupattu tripped due to Y-N and B-

N fault. 230kV ICT - 1, 2 & 3 and other 230kV feeders

were hand tripped.

44/I/1 (GD) Complete outage of Idukki Hydro Power

Station (GD-1)

28-04-2015 at

12:30 Hrs


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. ---------Pending

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.


1. Purchase procedures is still in progress.

2. Replaced.

3. PLCC equipment Tested and found OK.


1. Even though repeated plans to have a joint inspection with M/s.ABB

who is the OEM of the relay panel for replacing the relays with numerical

ones, the same could not become successful. Finally, the inspection has

been fixed on 15.03.2016. It has been planned to replace existing REF

protection with low impedance ones after retrofitting the numerical ones of

OEM.


1.Generation wing is planning ti provide low impedance REF protection by

retrofitting numerical ABB make transformer management relay in the

existing panel. ---- Pending.

2.Faulty breaker of Unit3 has been replaced. ---- Completed.

1. TANTRANSCO to restore cut communication link on 230 kV

Kadaperi – KV Pattu line in a week’s time.

2. TANTRANSCO to review Zone-2 time settings on 230 kV Kadaperi

– SP Budur lines 1 & 2 in line with Ramakrishna Committee

recommendations.

3. TANTRANSCO to correct A/R logic such that in the event of

another fault during A/R dead-time, A/R 3-ph trip with A/R block

shall be attempted. Further, if the carrier communication medium

becomes not available, A/R shall be blocked and 3-ph trip shall be

attempted.

TANTRANSCO Yet to be informed Pending

220 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.

1. 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.

Kerala

Pending

(Recommendat

ion No.1)

KSEB

66/ III/ 2 Tripping of 400 kV Alamathy-

SV.Chatram line-1

06-06-2017 at

22:03 hrs

R-phase to earth fault had occurred in line. Auto-

reclose was successful at Alamathy and breaker got

tripped at S.V.Chatram

1. TANTRANSCO to take up firmware issue of D60 relays with their

OEM, and get them upgraded appropriately.

2. TANTRANSCO to check the resistive reach settings of SV Chatram

end relays for the line under consideration.

TANTRANSCO Yet to be informed Pending

Annexure-II

Page 18 of 33

Pending

66/I/3 Complete outage of 220 kV Pothencode

substation of KSEB

11-07-2017 at

9:40 hrs

220 kV Buses – 1 & 2 got tripped due to operation of

busbar protection due to bus fault.

To ensure similar kind of events do not recur, KSEBL is

recommended to carry out the following:

1. Alignment issues w.r.t. the dedicator 89C isolator between Bus-1 &

Bus-3 and 89C isolator of Trivendrum-2 feeder between Bus-2 and

Bus-3 shall be immediately attended to.

2. Bus-Coupler CB between Bus-1 & Bus-2 shall be brought into

service at the earliest. Till this is done, Bus-Tie Isolator between Bus-

1 & Bus-2 shall be made use of as an additional parallel path to effect

changeover of Bus-1 connected elements on to Bus-2 or vice versa.

The respective connected source elements (transformers) can also be

de-energized before effecting required bus-changeover operations.

3. Since the required no. of breakers have not been provided to

smoothly effect various bus change-over operations, thermo-vision

cameras shall be used periodically to detect issues w.r.t. isolators &

breakers so as to take appropriate corrective action in time.

KSEB Yet to be informed Pending

23-08-2016

at 11:20 hrs

Triggering incident was conductor snapping in 110 kV

Kalamassery- Kaloor feeder

KSEB to take steps to provide the following at their 220/ 110 kV

Kalamassery SS:

1. Busbar protection at 110 kV level

2. Connecting 220 kV and 110 kV sides on to a common earthmat

3. Redundant DC supply for both protection (220 V) and

communication (48 V) applications

4. Stand-alone Event Logger

KSEB KSEB Mail received vide dated 17.01.2017:

1. 110 kV bus bar protection progressing ----Pending

2. Connection of 220kV earth mat and 110 kV plate earthing system

completed.---- Completed

3. Redundancy of 110V DC system in progress. Complete independent

redundancy is not practical for the time being. 48 V DC redundancy was

already there. ----Pending

4. Instead of stand alone event logger, SCADA system of 110 kV feeder is

expected to be completed by the end of 2017. SCADA system of 220kV

side will be taken up after that ----Pending

58/I/1 (GD) Complete outage of 220 kV Kalamassery

Substation

2.Faulty breaker of Unit3 has been replaced. ---- Completed.

3.PLCC equipments in the feeder were checked and found OK. ------

Completed.

Annexure-II

Page 19 of 33

08-05-2016at 4:57

hrs

Tripping of 400kV Hyderabad - N’sagar

line

55/II/5 Line tripped on operation of over-voltage protection at

Hyderabad end and Direct Trip was received at

N’sagar. Over-voltage, Stg-2 operation was observed

in EL of Hyderabad station.

1.PGCIL (SR-I) to properly configure EL’s at Hyderabad station

with time-scale resolution up to msec; further, DR’s should also be

configured for showing both Analog and Digital data with properly

defined X-axis and Y-axis scales.

2.PGCIL (SR-I) to follow the FILE Naming Nomenclature provided

by SRPC in naming various tripping files (FIR/DR/EL/TR) being

uploaded in SRLDC’s Tripping Monitor System (TMS) portal.

Yet to be informedPGCIL (SR-I)

PGCIL (SR-I & SR-II)

Pending

Annexure-II

Page 20 of 33

55/II/9 Tripping of HVDC Gazuwaka pole-2 19-05-2016 at

11:41 hrs

Pole tripped on operation of differential current

protection of east side of Pole-2

PGCIL (SR-I) to take up the issue of differential protection operation

of converter transformer on low voltage fluctuations with their OEM,

and submit a detailed report on it.

PGCIL (SR-I) Yet to be informed Pending

56/II/11 Tripping of HVDC GazuwakaPole-2 19-06-2016 at

5:20 Hrs

HVDC Pole-2 got tripped on operation of Bus

differential protection

PGCIL (SR-I) to get the tripping of HVDC Pole-2 tripping on Win-

Bus differential protection thoroughly investigated for correctness of

operation, and submit a report thereon.


56/III/7 Tripping of 400 kV Khammam-N’sagar

line-1

05-06-2016 at

22:41 hrs

Line tripped on B-phase to earth fault. Line auto-

reclosed successfully at N’sagar and failed to auto-

reclose at Khammam

1.PGCIL (SR-I) to configure DR & EL at N’sagar (Tallapalli) end so

that full operation of A/R is captured.

2.PGCIL (SR-I) to investigate the reasons for non-operation of A/R of

Tie-CB at N’Sagar end, and resolve them suitably.


58/II/13 (GI) Tripping of 400 kV Raichur-Gooty line-1

and 400 kV Gooty-Tumkur line-2

01-09-2016 at

5:17 hrs

400kV Gooty-Raichur line tripped at Gooty end only

and was holding from Raichur. 400kV Gooty-Tumkur

line-2 tripped on over voltage.

PGCIL (SR-I) to check the operation of OVR relays at their Gooty

SS, and properly configure lines’ DRs & ELs so that events pertaining

to OVR (Stage-I & Stage-II) operation (START & TRIP) get

explicitly recorded.


58/II/14 (GI) Tripping of 400 kV Gooty-Tumkur line-2 02-09-2016 at

21:56 hrs

Line tripped on operation of over-voltage protection at

Gooty end and Direct Trip was received at Tumkur

PGCIL (SR-I) to check the operation of OVR relays at their Gooty

SS, and properly configure lines’ DRs & ELs so that events pertaining

to OVR (Stage-I & Stage-II) operation (START & TRIP) get

explicitly recorded.


61/II/4 Tripping of HVDC Gazuwaka Pole-2 05-12-2016

at 15:03 hrs

Pole-2 tripped due to tripping of AC filter banks

which was due to voltage disturbance in eastern bus at

Gazuwaka.

PGCIL (SR-I) to refer the instant trippings to their OEM to ensure

that the settings adopted for pole trippings for low-voltage, power

swing, and ferro-resonance phenomena are in order and have been set

properly. A copy of the OEM’s reply in this regard shall be furnished

to PCSC forum.


62/II/4 Tripping of 400 kV Gazuwaka-Vemagiri

(PG) line and 400kV Vemagiri(PG)-

Nunna line

18-01-2017 at

22:03 hrs

400 kV Gazuwaka - Vemagiri (PG) line and 400 kV

Vemagiri (PG) - Nunna line got tripped due to Direct

Trip receive at Gazuwaka and Vijayawada

respectively

PGCIL (SR-I) to configure triggering of DR & EL for SF6 gas

compartment Zone trip with suitable legend.


63/II.11 Tripping of 765 kV Vemagiri-Srikakulam

line-1 and 765/400kV ICT-1 at Vemagiri-

PG SS

16-03-2017 at

10:23 hrs

Line-1 and ICT-1 which are in the same diameter got

tripped due to operation of Tie bay gas

compartment trip

1. Since tripping of elements on Gas Compartment Trip has been

observed frequently in the past few months at 765/ 400 kV

Vemagiri SS, PGCIL (SR-I) shall furnish a comprehensive report

detailing the remedial measures taken including OEM’s suggestions

to prevent their occurrence.


Tripping of 400 kV Ramagundam-

Warangal line

PGCIL (SR-I)

64/II/14

12-09-2016 at

12:03 hrs

Line tripped on Direct Trip receipt at Ramagundam

end and line was holding from Warangal end.

Yet to be informed

Yet to be informed

For the line under consideration, the following shall be carried out

by PGCIL (SR-I) in coordination with NTPC-Ramagundam:

I)End-to-end communication for DT/ permissive & other signals may

be ensured by testing at both the ends.

II)Healthiness of PLCC system components (hardware and software)

at both ends shall be checked and faulty components shall be

repaired/ replaced.

PGCIL (SR-I) Pending62/II/1

Pole-1 got tripped due to failure of auxiliary supply

changeover. 400kV Jeypore-Gazuwaka line-2 got

tripped on operation of over-voltage protection.

Pole-2 east shunt reactor got failed and this in turn

resulted in tripping of HVDC pole-2 due to Pole-2 Y

block activation. 400kV Jeypore-Gazuwaka line -1

also got tripped during the incident.

28-Apr-17 Pole-1

at 8:44 hrs and

Pole-2 at 9:07 hrs

Tripping of HVDC Gajuwaka Pole-1&2

and 400 kV Jeypore-Gazuwaka line-1&2

PGCIL (SR-I) Yet to be informed Pending1. PGCIL (SR-I) to provide fully automatic supply-changeover

scheme for Pole-1 auxiliaries at the earliest.

2.PGCIL (SR-I) to furnish a detailed report on the reasons for East

Shunt Reactor failure including remedial action taken. OEM report in

this regard also shall be shared.

05-01-2017

at 13:05 hrs

Tripping of 400kV Gazuwaka - Vemagiri

(PG) line and 400 kV Vemagiri (PG ) -

Nunna line

1. PGCIL (SR-I) to ensure time-sync of all protections relays at their

Vemagiri, Gajuwaka, and Vijayawada substations.

2. PGCIL (SR-I) to check OVR settings for correctness of operation

along with proper drop-off to pick-up ratio (> 0.97), and configure

OVR_START event in the corresponding Relay/ BCU Event Logger for

all 400 kV lines emanating from their Vemagiri (PG) SS.

Pending58/IV/1

400 kV Gazuwaka-Vemagiri (PG) line tripped on Y-E

fault. However, for 400 kV Gazuwaka-Vemagiri (PG)

line, Direct Trip was received at Gazuwaka after

250ms of occurrence of fault and fault was

persistent for 250ms. Then, Over-Voltage, Stage-1

protection operated from Vemagiri (PG) end in 400

kV Vemagiri (PG) - Nunna line and tripped it

Annexure-II

Page 21 of 33

64/III/16 Tripping of 76 5kV Kurnool-Nellore PS

line-2

27-04-2017 at

22:22 hrs

R-phase to earth fault had occurred in line. Auto-

reclose was successful at Kurnool end and breaker at

Nellore PS end tripped and did not attempt for auto-

reclose.

For the line under consideration, PGCIL (SR-I) to Configure Event

Logger (EL) to record events at msec level.


65/II/15 Tripping of HVDC Gazuwaka Pole-1&2 25-05-2017 at

09:45 hrs

HVDC pole-1 got tripped due to operation of South

filter inter zone protection and HVDC pole-2 got

tripped due to operation of differential protection

PGCIL (SR-I) to furnish detailed report on the events that led to

tripping of HVDC Poles – 1 & 2 including remedial measures taken

to PCSC forum. Further, the OEM report w.r.t. tripping of HVDC Pole-

2 shall also be furnished.


65/III/5 Tripping of 765 kV Raichur-Solapur line-

2

07-05-2017

at 19:18 hrs

Y-phase to earth fault. Auto-reclose was successful

at Solapur and breakers at Raichur end got tripped

PGCIL (SR-I) to configure Event Logger’s time-resolution up to

millisec level in all protection relays at their 765/ 400 kV Raichur SS.


55/II/7 Tripping of 400kV Kudgi PG (Narendra

New) - Narendra-PG line-2

18-05-2016 at

16:25 hrs

line tripped on B-phase to earth fault and line auto-

reclosed successfully from Narendra end. Line tripped

from Kudgi-PG due to operation of over-voltage stage-

1

PGCIL (SR-II) to properly configure dead-time of A/R (typically 1

sec) on all lines emanating from Narendra (PG) substation.

PGCIL (SR-II) Yet to be informed Pending

54/II/3 Tripping of 400kV Sriperambudur -

SV.Chartam and 400kV Nellore-

Sriperambudur line-1

05-04-2016 at

00:11 hrs

400kV Nellore-Sriperambudur line-1 tripped on a R-

phase to earth fault. 400kV Sriperambudur-

S.V.Chatram line tripped at Sriperambudur end only

on operation of over current protection

PGCIL (SR-II) to check and revise Pole Discrepancy Relay (PDR)

time setting appropriately based on the type of A/R scheme being

implemented at their 400 kV Sriperambudur SS.


54/III/3 Tripping of 400 kV Kalvindapattu-Vallur

line

10-04-2016 at

14:59 hrs

R-phase to earth fault had occurred in line. Auto

reclose attempt is unsuccessful/ auto-reclose could not

be established from provided DR/ EL.

PGCIL (SR-II) to furnish a report on the tripping event detailing the

reasons for unsuccessful A/R operation at Kalvindapattu end, and the

remedial action taken to restore A/R to normalcy.


55/II/17 Tripping of HVDC Talcher-Kolar pole-1 30-05-2016 at

09:49 Hrs.

Failure of main CT of AC filter (20C08A) occurred

and it in turn caused the operation of filter bank

differential protection. HVDC Pole-1 got tripped on

group Differential protection operation

PGCIL (SR-II) to take up the issue of Pole-1 tripping on Group

Differential Protection (Stage-II) due to multiple commutation failures

with their OEM, and furnish a report on it.


56/II/8 Tripping of HVDC Talcher-Kolar Pole-1 17-06-2016 at

16:35 Hrs

Talcher-Kolar HVDC Pole-1 got tripped on line fault

and Pole-2 went to ground return mode with 150MW

PGCIL (SR-II) to address & resolve DTPC and fibre-optic link

related issues raised by KSEB at Thrissur/ Madakathara substations,

and conduct a mock-test in coordination with KSEB to verify integrity

of signal transmission from Kolar to Thrissur/ Makadathara.


57/II/2 Tripping of 400 kV Mywady-Salem line-1

and 400 kV Mywady-Madurai line

PGCIL (SR-II) to furnish a report on the remedial action taken after

ascertaining the reasons for (i) non-opening of Main-CB of Mywady

– Madurai line at Mywady end on Tie-CB LBB operation, and (ii)

delay in sending DT to the remote ends after Tie-CB LBB operation.

65/III/10

03-07-2016 at

03:06 hrs

400kV Mywady- Madurai line tripped on a Y-phase

to earth fault due to agriculture fire. Tie-CB LBB

relay got operated at Mywady end and resulted in

tripping of Main breakers of 400kV Mywady-

Madurai and 400kV Mywady-Salem line-1 which are

in the same diameter.

PGCIL (SR-I) to sort out issues relating to A/R functionality/

operation for both Main-CB and Tie-CB at both Vemagiri and

Gajuwaka substations.


by PGCIL (SR-I):

! End-to-end communication for DT/ permissive & other signals


! Healthiness of PLCC system components (hardware and software)


repaired/ replaced.

Y-phase to earth fault. Auto-reclose was not

successful due to persistent fault. Vemagiri end had

sent a Direct Trip after un-successful Auto-reclose.

A/R attempt was observed in Gazuwaka end DR

after 3 phase trip

14-05-2017

at 16:54 hrs

Tripping of 400 kV Vemagiri - Gazuwaka

line

PGCIL (SR-I)

also got tripped during the incident.3.PGCIL (SR-I) to provide redundant AC auxiliary supply to both

Pole-1 & Pole-2 either by making use of tertiary of ICT-1 or from

external dedicated feeder


PendingPGCIL (SR-II) Yet to be informed

Annexure-II

Page 22 of 33

58/II/3 (GI) Tripping of 400 kV Sriperambudur-

SV.Chatram line

14-08-2016 at

13:49 hrs

Line tripped at Sriperambudur end only on

operation of directional earth fault protection

(i) PGCIL (SR-II) to disable high-set of line DEFR’s, and

(ii) PGCIL (SR-II) to block line DEFR operation when DPR is in active

condition (has picked up) at their Sriperambudur SS.


58/II/5 (GI) Tripping of 400 kV Neyveli TS2-Pugalur

line and 400 kV Neyveli TS2-Neyveli TS2

EXP line

21-08-2016 at

10:35 hrs

Failure of Y-Ph tension insulator of tie feeder bay at

Neyveli TS2. Neyveli-Pugalur line tripped due to over

voltage at Neyveli TS2 and direct trip was received

at Pugalur.

PGCIL (SR-II) to check the operation of the DPR relays at Pugalur

end NLC TS2 - Pugalur line by trans-playing the event on another

healthy relay, and take suitable action including replacement of the

relay accordingly.


58/II/19 (GI) Tripping of 400 kV Madurai-Karaikudi

line

15-09-2016 at

03:02hrs

Line tripped on operation of OVR, Stage-I protection

at Karaikudi and Direct Trip was received at Madurai

PGCIL (SR-II) to check the operation of OVR relays at their 400 kV

Karaikudi SS, and properly configure lines’ DRs & ELs so that events

pertaining to OVR (Stage-I & Stage-II) protection operation (START

& TRIP) get explicitly recorded.


59/II/20 (GI) Tripping of HVDC Talcher-Kolar pole-1 10-10-2016 at

16:35 hrs

Pole-1 of HVDC Talcher-Kolar tripped due to receipt

of ‘’Pole block command from Talcher end due to

tripping Pole-1 DC filter at Talchar end. Pole 2 went

into metallic return mode after tripping of pole-1

PGCIL (SR-II) to check the correctness of non-operation of SPS

(Talcher –Kolar Trip Signal-1) in the instant case by comparing it

with the incident of tripping of HVDC Talcher-Kolar pole-1 on

05.10.2016, and furnish a report on it to PCSC forum.


59/II/24 (GI) Tripping of 400/220kV ICT-2 at

Somanahalli SS

24-10-2016 at

3:54 hrs

ICT-2 tripped on operation of Buchholz relay PGCIL (SR-II) to properly configure ICT protection relay DR so that

digital signals are recorded with proper names at their 400/220 kV

Somanahalli SS.


59/III/4 Tripping of 400 kV Salem -Udumalpet

line-2

13-10-2016 at

03:06 hrs

Line tripped on R-phase to earth fault. Line auto-

reclosed at Udumalpet end and did not reclose at

Salem

PGCIL (SR-II) to configure protection relay DR & EL for 400 kV

Salem -Udumalpet line-2 at Udumalpet end for proper time-scale

and A/R operation related events.


62/III/5 Tripping of 400 kV Tumkur – Bidadi line 17-02-2017

at 10:44 hrs

B-E fault. Line did not auto-reclose 1. PGCIL (SR-II) to properly configure A/R logic operation at Bidadi

end, and ensure it’s correct operation for a fault during reclaim

time.

2. PGCIL (SR-II) to ensure time-sync of protection relays with GPS at

both Tumkur and Bidadi substations.


62/III/6 Tripping of 400 kV Tumkur – Bidadi line 18-02-2017

at 10:36 hrs

B-E fault. Line did not auto-reclose PGCIL (SR-II) to properly configure A/R logic operation at Bidadi

end, and ensure it’s correct operation for a fault during reclaim

time.


62/V/1 Tripping of 400kV Vallur-Kalivandapattu

line-2

22-02-2017 at

4:55 hrs

Line tripped due to failure of R phase jumper. Two

faults observed from DR. 2nd fault cleared in 500ms

from Kalavindapattu end.

PGCIL (SR-II) to enable Trip on Reclose (TOR) at Kalavindapattu end

on all 400 kV lines emanating from it.


65/II/2 Tripping of 400 kV Kudgi (PG) - Tumkur

line-2 and Kudgi (PG) – Kudgi (NTPC) line-

1

06-05-2017 Kudgi (NTPC) feeder tripped at Kudgi (PG) end on

operation of distance protection R-N, Zone-1.

Tumkur feeder tripped at Kudgi(PG) end on

operation of NGR buchholtz relay.

1. PGCIL (SR-II) to sort out A/R related issues at Kudgi (PG) end on

400 kV Kudgi (PG) – Kudgi (NTPC) lines, and put A/R into service.

2. PGCIL (SR-II) investigate reasons for NGR Buccholtz trip on 400

kV Kudgi (PG) – Tumkur line-2, and furnish action taken report w.r.t.

rectifying the same.


58/II/16 (GI) Multiple tripping at 400 kV Kalpaka SS 06-09-2016 at

16:43 Hrs

Y-Pole breaker of Bus reactor-3 got failed during its

charging. This resulted in a bus fault in 400kV bus-1

resulting in tripping of 400kV elements connected to

Bus-1

PGCIL (SR-I) & PGCIL (SR-II) to review their Reverse Zone settings of

distance relays so as to bring them in line with Ramakrishna

Committee guidelines at all their substations in the southern region.

PGCIL (SR-I) & PGCIL

(SR-II)


62/II/6 Tripping of 400 kV Trichy-Karaikudi line 21-01-2017

at 21:45 hrs

Line tripped on operation of over voltage protection

at Karaikudi end and direct trip was received at

Trichy. Voltage recorded in DR in antecedent

conditions were 245.4 kV, 243.2 kV, 253.6 kV

respectively

1. PGCIL (SR-II) to ensure OVR settings adopted for 400 kV lines at

Karaikudi SS are as per SRPC provided settings with a drop-off to

pick-up ratio > 0.97.

2. PGCIL (SR-II) to configure OVR_START event in the corresponding

Relay/ BCU Event Logger for all 400 kV lines emanating from their

Karaikudi SS.


Annexure-II

Page 23 of 33

NTECL400kV Vallur-Alamathy Line-2 got tripped from

Vallur end during failure of Y-phase LA in 400kV

Alamathy-Tiruvalam line. Protection at Vallur end

tried for an auto-reclose and gave a 3 phase trip.

NTECL, Vallur to furnish a report detailing the reasons for mal-

operation of Vallur end relays for a fault on Alamathy-Tiruvalam line-

1, and remedial measures taken to PCSC forum. In the report, their

preparedness for implementing line differential protection on Vallur-

Alamathy lines may also be indicated.

Tripping of 400kV Alamathy-Tiruvalam

line-1 and 400kV Alamathy-Vallur line-2

51/II/4 TANTRANSCO mail received on 24-03-2016:

3Ф Trip at 400kV Alamathy end due to DT received from vallur end for

BФ LAS bursted in Alamathy -Thiruvalam - 1 # at Alamathy end.

Mail received on 27-04-2016 and 20-05-2016:

3Ф Trip at 400kV Alamathy end due to DT received from vallur end for

BФ LAS bursted in Alamathy -Thiruvalam - Line-1 at Alamathy end.

Pending13-12-2015 at

22:42 hrs

Others

Annexure-II

Page 24 of 33

56/III/5 Tripping of 400 kV Neyveli TS-2-

Pugalur line

04-06-2016 at

16:36 hrs

B phase to earth fault occurred in line. Auto-reclose

had not operated at NLC TS-2 and DT was sent to

Pugalur end resulting in a 3 phase trip

NLC to review the necessity of providing Relay Definitive Trip, and

accordingly take steps to disable it on all lines emanating from their

generating stations.

NLC Direct trip triggering of DR wii be carried out at TS2 end during the next

planned shutdown of the Pugalur Ts2 feeder


Direct trip triggering of DR carried out at TS2 end for the TS2-Pugalur

feeder on 25-01-17

Pending

56/II/16 Tripping of 400 kV Gajwel-Singareni

line-2

30.06.2016 at

23:43 hrs

Tripped on 3-phase Trip at Gajwel end SCCL to configure Jaipur end relay’s EL properly so that the time-

stamp resolution is extended downwards up to milli-second level.

SCCL Yet to be informed Pending

62/III/2 Tripping of 400 kV Kaiga-Guttur line-1 06-02-2017

at 05:01 hrs

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

Kaiga end.

1. KGS to properly configure all relays DR’s time scale for a post-

triggering period of 2 sec to capture events such as complete A/R

operation.

2. KGS to ensure time-synchronization of all protection relays with

GPS in their 400 kV switchyard.

NPCIL (KGS) Yet to be informed Pending

Line tripped on B-phase to earth fault. Line auto

reclosed at Chandrapur end and did not reclose at

Ramagundam

57/II/4 1.Singareni TPS to furnish single line diagram of their switchyard

along with the Over Voltage Relay settings adopted for various

transmission lines, and to ensure that they are in line with the SRPC

provided gradings.

2.Singareni TPS to upload various tripping files (FIR/DR/EL/TR)

pertaining to a tripping event involving their station in SRLDC web-

portal within 24-hrs of occurrence of that event in compliance of

IEGC Regulation 5.2(r).

59/III/3

57/II/8 NTPC (Ramagundam)

10-07-2016 at

1:56 hrs

Line tripped at Ramagundam end on operation of over-

voltage protection. Dichipally end tripped due to

receipt of Direct Trip signal.

1.NTPC-Ramagundam to ensure correctness of operation of Over

Voltage relays by taking remedial measures like maintaining

healthiness of concerned CVT’s, setting drop-off to pick-up ratio at

0.97 & above, etc.

2.NTPC-Ramagundam to ensure time sync of their station’s DR & EL

with GPS.

3.NTPC-Ramagundam to sort out analog values indication &

overlapping issue of time-stamp in their station DR’s.

4.NTPC-Ramagundam to properly configure their EL’s so that events

are recorded with msec. resolution.

Tripping of 400 kV Ramagundam -

Chandrapur line -2

1.NTPC-Ramagundam to furnish remedial measures taken w.r.t. A/R

non-operation and unwarranted DT sending to other end.

2.NTPC-Ramagundam to configure protection relays DR’s such that

events get recorded for at leas

2000 msec post-triggering so as to cover complete A/R operation.


Dichipally line

16-07-2016 at

4:38 hrs

1.MAPS to furnish a detailed report on the tripping of SP Koil –

MAPS lines 1 & 2 at MAPS end with focus on the correctness of the

settings of Main-I & Main-II relays (for primary & back-up

protections) on both the lines.

2.MAPS to take steps to provide down-loading facility for DR & EL

from Main-I & Main-II relays on all 230 kV lines emanating from

MAPS.

3.MAPS, in co-ordination with SP Koil, to carry out PLCC end-to-

end testing, on SP Koil – MAPS lines 1 & 2, and ensure healthiness

of PLCC communication & carrier-aided protection.

4.MAPS to put in service Auto-Reclosure feature on all four 230 kV

lines emanating from MAPS by June, 2016.

PendingLine tripped on operation of Over-Voltage

protection at Singareni and Direct Trip was received

at Gajwel. DR & EL of Singareni was not furnished

Pending

Tripping of 400 kV Gajwel-Singareni line-

2

02-04-2016 at

17:08 hrs

NTPC-Ramagundam mail dated 09.03.2017:

1. Main-II relay replaced, Over voltage relays pickup to reset ratio is 0.98.

--- Completed

2. DR and EL are time synchronized with GPS clock.

-------- Completed

3.DR alalog overlaping issue is sloved. ---- Completed

4. ----- Pending

Yet to be informed

Pending

54/I/1 Complete outage of 230 kV S.P.Koil

Station of TANTRANSCO

B-phase CT failure occurred in 230 kV S.P.Koil -

MAPS line-1. Busbar protection got operated at

SP.Koil station. All elements except 230kV

Oragadam and 230kV Kalivandapattu got tripped at

230kV S.P.Koil station. ‘Y’ phase CT and support

insulators also got damaged.

27-09-2016 at

01:01 hrs

NPCIL (MAPS)

SCCL

PendingNTPC NTPC-Ramagundam mail dated 09.03.2017:

1. The relay will be checked in next opportunity, if required it will be

changed with new one.------------- Pending

2.DR time recording increased to 2 sec --------- Completed

Status revided vide MAPS mail dated 06.12.2016;

1. The settings given by M/s TANTRANSCO were adopted for Main –I &

Main- II relays for both the lines. The same settings were verified to be

same. Subsequently calibrated was done and no drift was observed.

--- Complied

2. From May 2016 onwards, the DR, EL and trip report are being sent by

mail to SRLDC, Bengaluru by MAPS.

--- Complied

3. Monthly maintenance of PLCC equipments is being done by M/s

TANTRANSCO. At present PLCC telephone is not working, it is being

followed up.

--- Complied

4. CVTs are planned to be procured from M/s TANTRANSCO by the end

of February 2017 and A/R will be implemented for all the lines emanating

from MAPS by July-2017 as discussed in the current SRPC meeting on

25/11/2016.

--- Pending

Annexure-II

Page 25 of 33

63/III.4 Tripping of 400 kV Gajwel-Singareni line-

2

07-03-2017 at

16:52 hrs

Line tripped on B-phase to earth fault. Line did not

auto-reclose.

1. SCCL to properly configure LBB logic for all line relays,

where A/R has been put into service, for 1-ph initiation based

on phase segregation (i.e., for the faulted phase) at their

Singareni TPS.

SCCL Yet to be informed Pending

64/II/8 Tripping of 400 kV Tirunelveli-

Kudankulam line-3

23-04-2017 at

05:56hrs

R-phase to earth fault had occurred in Tirunelveli -

Udumalpet line-2. During the incident, Tie-CB LBB

got operated at Tirunelveli end due to sluggish

operation, and tripped 400 kV Tirunelveli -

Kudankulam line-3

NPCIL (KKNPP) to configure DR’s & EL’s of protection relays at their

station for recording DT receipt event at their Kudankulam NPP.

NPCIL(KKNPP) Yet to be informed Pending

66/ II/ 17 Tripping of 400 kV Kudankulam-

Tirunelveli line-2

25-06-2017

at14:48 hrs

Line tripped on operation of overvoltage protection

at Kudankulam

66/ II/ 18 Tripping of 400 kV Kudankulam-Madurai

line

25-06-2017 at

15:02 hrs

Line tripped on operation of overvoltage protection

at Kudankulam

66/ II/ 20 Tripping of 400 kV Tirunelveli-

Kudankulam line-2

26-06-2017 at

1:38 hrs

Line tripped on operation of Over Voltage protection

at Kudankulam and Direct Trip was received at

Tirunelveli

Yet to be informedTripping of 400kV Kaiga-Guttur line-2 Line tripped on Y-phase to earth fault. Line auto-

reclosed from Guttur end and failed to re-close from

Kaiga end

1. NPCIL (KGS) to furnish an action taken report on the

reasons for A/R lock-out, and remedial action taken to rectify

the same.

2. NPCIL (KGS) to configure DR’s of line protection relays


operation at their Kaiga GS.

3.NPCIL (KGS) to furnish FIR & TR for tripping events as

per SRLDC provided formats.

27-03-2017 at

7:06 hrs

63/III.8 NPCIL (KGS) Pending

1. KKNPP to disable external electromagnetic type OV relays

provided in their 400 kV lines, and provide the same from the

corresponding main protection relays.

2. KKNPP to check the healthiness of line CVT’s in view of sensing of

very high voltages by them even though the grid voltage is normal

around the tripping event.

NPCIL(KKNPP) Yet to be informed Pending

Annexure-II

Page 26 of 33

34/I/6

01-01-2015 at

13:38 hrs

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.

As reported directional over current relay of ICT’s

operated due to snapping of line jumper in 220kV

Lingapur line.

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.

16-07-2014 Pending

(with KPTCL)

Tripping of 400

kV TALAGUPPA

– HASSAN line

40/II/3

Multiple tripping at Raichur TPS of

KPCL

42/II/18

400/220 kV ICT-1 & 2 at

MUNIRABAD

09-03-2015 at

06:36 hrs

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.

Multi-Utilities

Pending (with

KPCL)

KPCL/

TSTRANSCO/

PGCIL (SR-I)

PGCIL (SR-II)/ KPTCL

KPTCL/

PGCIL (SR-I)


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 discrepancy in the relay operation is to be checked jointly.

Mail recieved on 02-09-2015 from PGCIL (SR-II):

Problem is in identification of phases at Talguppa end. To be rectified by

M/s KPTCL.

Mail recieved on 28-06-2016 from KPTCL:

The matter is reffered to the concerned Operation and maintance wing to

set right the mismatch of phases in 400kV Talaguppa-Nelamangala and

Talaguppa-Shantigrma lines at Talaguppa in cordination with PGCIL .

1. Yet to be informed by KPCL. ---- Pending

2. 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. -- Complied with

3.

PGCIL mail recieved on 27-04-2016:

End to end PLCC tunning carried out.

PGCIL (SR-I) RVMD 14.07.2016:

Relay settings of all the stations in SRTS-1 were derived as per

Ramakrishna Commettee recomendations and implemented. - Complied

with.

Pending

(with 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

KPTCL Mail recieved on 23-01-2016:

Detailed estimate prepared for taking up the work. CEE, Transmission

Zone, Gulbarga will take up necessary procurement and further execution.

----------------------------------------------------------------------

1. Pending from KPTCL side.

2. Complied with as per PGCIL (SR-I) RVMD 14.07.2016, which stated

that "Relay settings of all the stations in SRTS-1 were derived as per

Ramakrishna Commettee recomendations and implemented."

3. Pending from KPTCL side.

Annexure-II

Page 27 of 33

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

Krishnapatnam

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.

Complete outage of Krishnapatnam TPS

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/

APGENCO/ TNEB

Pending (with

KPCL)

APGENCO letter dated 18.03.2016:

1.SOE and SLD are attached. The DR of 405 CB is not generated during

the incident. Now the problem is identified and rectified.

--------- Completed

2.All the 3 lines i.e CHTR-2, MNBL-I & II tripped in zone

protection. The fault was in Blind zone i.e P2 side of CT, where it was

covered under Bus fault by the time fault moved on to P1 side when the

fault comes under STUB/TEED zone after 330msec all the feeders expect

CHTR-1 tripped in Zone-II and total fault persisted for 500msec before the

405 TIE CB opens and clear the fault. As a remedial the STUB protection

operation also checked and found OK.-------Completed

3.The Time Sync was missed on the day and found there was problem with

LAN Timer same was rectified. Now found OK.

-----------Completed

4.Now the DR Time scale changed to 1 sec for Pre fault and 3 sec for Post

fault and STATE of events are corrected wherever found wrong/or

misguiding during analysis.---------Completed.

5.

PGCIL-SR1 RVMD 27-04-2016:

Procurement of differential protection for 400kV NPS-NLR D/C and

400kV RCR-RTPS-D/C is under tendering.

PGCIL-SR1 RVMD 14-07-2016:

The proposal for procurement of Line differential Protections for 400kV

Raichur - RTPS-1 & 2 and 400kV Nellore - NPS - 1 & 2 lines has been

approved and tender is under technical evaluation

Pending with

PGCIL (SR-I)

08-09-2015 at

18:20 hrs

As per FIR submitted, CT damage observed in

Chitoor-Main bay (404). Main breakers connected to

bus-1 (401, 404, 407, 410) got tripped on operation of

bus bar protection. Unit-1 tripped on operation of

MFT. Unit-2 was not in service

44/I/3

47/I/2 1. APGENCO to furnish to PCSC forum (i) A3-size Single Line

Diagram of SDSTPS, and (ii) the sequence of events with time stamp

showing the protection that opened Tie-CB (405) at SDSTPS.

2. APGENCO to review STUB/TEED protection in all dias at

SDSTPS and ensure that they are configured for instantaneous

operation.

3. APGENCO to properly configure the STATE of the tripping events

so that they get recorded appropriately like TRIP/ OPERATED in

their corresponding Event Loggers.

4. APGENCO to ensure time sync of all DR’s and EL’s at SDSTPS.

5. PGCIL (SR-I) to provide line differential protection for 400 kV

NPS –Nellore-PG lines 1 & 2.

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.

MEPL vide their mail dated 14.09.2015 informed that they had

implemented 2 seconds delay for under voltage tripping of all Drag Chain

Feeder Conveyors. And this has been done for both the Units.

APGENCO letter dated 18.03.2016:

The unit not tripped on Generator protection but tripped on Economiser

inlet flow protection consequent to tripping of TDBFP on lube oil pressure

low.Before tripping , dip in voltage was observed in the LT system which

caused tripping od lube oil pumps.After the incident,Changeover scheme on

under voltage of LT System was reduced from 80% with 2 sec delay to

40% with 200msec delay

APGENCO/

PGCIL (SR-I)

Annexure-II

Page 28 of 33

PGCIL (SR-I) / KPTCL 1. For Gooty –Nelamangala line, PGCIL (SR-I) and KPTCL to

provide 3-ph trip logic at their respective ends upon detection of

PLCC link failure during dead-time of A/R operation.

2. PGCIL (SR-I) to make GPS functional at Gooty SS, and ensure

time-sync of various DR’s and EL’s with it (GPS).

3. PGCIL (SR-I) /KPTCL to furnish reason for the operation of

Backup impedance protection of the line reactor at Nelamangala end

and the remedial measures taken to PCSC forum.

1.PGCIL (SR-I) to furnish Action Taken Report on the findings of

OEM on relay mal-operation at NPS end on 400 kV NPS – NCCK

line to PCSC forum.

2. PGCIL (SR-I) to appropriately configure Station Event Logger at

NPS to record events at msec interval.

3. PGCIL (SR-I) to carry out PLCC end-to-end testing in coordination

with TPCIL for 400 kV NPS –TPCIL line.

4.PGCIL (SR-I), MEPL, SEL, TPCIL & NCC to take steps to provide

line differential protection at their respective ends on all 400 kV lines

(except Gooty line) emanating from Nellore Pooling Station, and

furnish an action plan to implement the same.

Pending

PGCIL (SR-I) mail received on 27-04-2016:

1. The firmware of REL670 is being upgraded. ------- Completed.

2. The recording of events in msec interval is being taken up with OEM.

Henceforth, for analysis purpose, we will provide larm list which has msec

time stamp. -------- Completed.

3. End to end testing of PLCC code transmision and tuning of channels

carried out. ------- Completed.

4. Procurement of differential protection for 400kV NPS-NLR D/C and

400kV RCR-RTPS-D/C is under tendering. The legends modified in

Event/alarm list. Provision of diff. rel;ay for all short lines emanating from

NPS is being taken up with our corporate. -------- Pending.

PGCIL(SR-I) RVMD 14-07-2016:

The proposal for procurement of Line differential Protections for 400kV

Raichur - RTPS-1 & 2 and 400kV Nellore - NPS - 1 & 2 lines has been

approved and tender is under technical evaluation

1.

PGCIL RVMD 27.04.2016:

A/R blocked due to failure of PLCC link. The defective PLCCcards

replaced at Neelamgala end.


A/R blocked due to failure of PLCC link. The defective PLCCcards

replaced at Neelamgala end. End to end testing of PLCC carried out and

PLCC link is healthy. ------ Pending

2. Gooty end Time syc unit is replaced with new one and commissioned. ----

---- Completed.

3. Yet to be informed by KPTCL. --- Pending

Running units at Thermal Powertech power Station

tripped due to tripping of 400kV Nellore pooling

station (NPS)-TPCIL line and 400kV Nellore pooling

station (NPS)-ECC line

30-12-2015 at

06:02hrs

R-phase to earth fault had occurred in Line. Line did

not auto-reclose from both ends. It was mentioned that

Y&B pole breakers at Neelamangala tripped on

operation of pole discrepancy and backup impedence

protection for line reactor got operated.

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 protection.

12-11-2015 at

00:20 hrs

Complete outage of TPCIL power station 50/I/2

50/II/8

47/II/7 Tripping of 220kV Kadra-Karwar lines -

1&2 and 220kV Kaiga-Kadra line

Tripping of 400kV Gooty-Nelamangala

line

1. KPTCL/ KPCL to see the possibility of implementing Weak Infeed

logic with Echo feature enabled by Under

Voltage (27) element on Kadra-Karwar lines 1 &2, and implement the

same if feasible.

2. NPCIL to time-coordinate Kaiga’s DEFR settings with (i) Zone-2

settings at Kaiga, and (ii) primary protections of the lines emanating

from Kadra and Kodasalli.

3. KPCL to ensure time-sync of EL’s, and healthiness of the Fault

Locators at Kadra.

PendingPGCIL (SR-I),

MEPL, SEL, TPCIL,

NCC

KPTCL/ KPCL/ NPCIL

(KAPS)

1.

Mail recieved on 25-05-2016 from KPTCL:

Availability of week end infeed with eco feature to be confirmed by

SEE,RTC,Hubli --- Pending.

2.

Mail recieved on 03-12-2016 from NPCIL(KGS):

The 200 ms Definite time DEFR element in both Kaiga Kadra and Kaiga

Kodasally lines were disabled. IDMT DEFR is retained. The 200 ms

Definite time back up o/c element in both Kaiga Kadra and Kaiga

Kodasally lines were disabled. IDMT is retained.

------ Completed.

3. Yet to be informed by KPCL


1. Since PT blasted (B phase) at Karwar end, resistive over reach occurred.

hence Backup protecion operated at Kadra end (zone-2 not sensed) ---

Pending.

3.Newly commissioned micom P444 relay time synchronised with GPS

------ Completed.

Pending (with

KPTCL)

Annexure-II

Page 29 of 33

52/I/8 Complete outage of 400kV NTPL station

and CEPL Stations

14-03-2016 at

01:36 hrs

Running Units at NTPL and Coastal Energen power

station got tripped due to tripping of evacuating lines.

NTPL and PGCIL (SR-II) to furnish compliance report of the

recommendations given by PSAG-15 Committee that held its meeting

on 12-13 April, 2016 at NTPL, Tuticorin.

PGCIL (SR-II)/

NTPL

NTPL mail received on 19.05.2016:

All General Recommendations will be done in the second week of June

2016 ---------- Complied by NTPL.

Yet to be informed by PGCIL (SR-II)

Pending

[with PGCIL

(SR-II)]

56/III/4 Tripping of 220 kV Sedam-Tandur line 03-06-2016 at

21:52 hrs

Line tripped on B-phase to earth fault. Auto-reclose is

not enabled for line.

KPTCL and TSTRANSCO to fast-track providing A/R on 220 kV

Sedam – Tandur line, and furnish an action plan of providing the same

by next PCSC meeting (PCSC-57).

KPTCL/

TSTRANSCO



TSTRANSCO and PGCL (SR-I) in co-ordination:

i.End-to-end communication for DT/ permissive & other signals may


ii.Healthiness of PLCC system components (hardware and software)


replaced.

PGCIL (SR-I)/

TSTRANSCO

Yet to be informed

Pending

1.TSTRANSCO and SCCL to check drop-off to pick-up ratio of OV

relay and ensure that it is kept at 0.97 & above.

2.TSTRANSCO and SCCL to configure respective end ‘s DR & EL

so that they get triggered on OVR protection, and record relevant

events.

3.SCCL to configure Jaipur end relay’s EL properly so that the time-

stamp resolution is extended downwards up to milli-second level.

TSTRANSCO/

SCCL

Yet to be informed

PGCIL mail received on 27-04-2016:

Being pursued with APTRANSCO


AS maintenance being carrired out by PGCIL(SR-1), the required relay

replacement (wiring/programming) may also be carried out by PGCIL(SR-

1).


1. The CB problem has been attended by POWERGRID by using OEM

M/s BHEL services & POWERGRID's O&M spares.

------ Completed.

2. Being pursued with APTRANSCO to replace the faulty Event Logger at

Vijayawada (Nunna) SS. -------- Pending

APTRANSCO mail dated on 31-08-2016 & 04.03.2017 & 24.05.2017:

As maintenance being carrired out by PGCIL(SR-1), the required relay

replacement (wiring/programming) may also be carried out by PGCIL(SR-

1).

Yet to be informed

PGCIL (SR-I)/

APTRANSCO

1. PGCIL (SR-I), in co-ordination with APTRANSCO, to address the

problem with CB at the earliest opportune time.

2. APTRANSCO to take steps to replace the faulty Event Logger at

Vijayawada (Nunna) SS.

Pending

Line tripped due to operation of over voltage

protection at Vijayawada end and Direct Trip was

received at Sattenapalli end

25-12-2015 at

3:01 hrs

Tripped on 3-phase Trip at Gajwel end30.06.2016 at

23:43 hrs

19-06-2016 at

15:27hrs

220kV Sedam-Humnabad-2 tripped at Sedam on

Distance protection, Zone-2. Sedam-RTPS-1 &2 lines

tripped at RTPS end only. 220kV Tandoor inter-state

line was hand tripped due to incoming supply failure

Tripping of 400kV Sattenapalli-

Vijayawada line

56/I/2

51/II/6

Complete outage of 220kV Sedam


54/IV/2 Tripping of 400kV Ghanapur-

Mamidapalli line

56/II/16 Tripping of 400 kV Gajwel-Singareni

line-2

Line tripped at Mamidipally end only on Direct Trip

receipt from Ghanapur end

30-04-2016 at

16:40 hrs

KPTCL and TSTRANSCO to take steps to provide A/R feature on

220 kV Sedam – Tandur inter-state line at their respective ends at the

earliest.

KPTCL/

TSTRANSCO

Pending

Pending

Annexure-II

Page 30 of 33

R-phase to earth had occurred in 400kV BTPS-JSWEL

line and protection issued a 3 phase trip

64/I/1 Complete outage of North Chennai TPS

STG-2

24-04-2017

at 21:02hrs


tripping of Units

Pending


STG-2

25-04-2017

at 18:27hrs


tripping of Unit


STG-2

26-03-2017

at 21:09 hrs


tripping of running Unit at NCTPS Stg-2

64/III/2 Tripping of 400 kV Ghanapur-

Mamidapalli line

04-04-2017 at

19:01hrs

B-phase to earth fault. Line auto-reclosed from

Mamidapalli end and tripped from Ghanapur

For the line under consideration, PGCIL (SR-I)/ TSTRANSCO to (i)

rectify issues w.r.t. PLCC channels, (ii) restore PLCC carrier

communication, and (iii) put A/R into service at the earliest.

PGCIL (SR-I)/

TSTRANSCO


Triggering incident was failure of CT in 110 kV

Villianur-Kurumbapet at Villianur substation. 230KV

Villianur – NLC2 and 230 kV Villianur - Pondy lines

got tripped from Pondy end (on operation of DEF)

and NLC end (on operation of Zone-3) respectively

resulting in loss of supply to 230 kV Villianur

substation

19-05-2017 at

12.35 hrs

Complete outage of 230 kV Villianur

Substation of Pondicherry

65/I/1 PED/ PGCIL (SR-II)/

NLCIL

1. PED to furnish an action taken report w.r.t. complying with the

protection audit recommendations.

2. PGCIL (SR-II) to review Zone-3 and DEF protection setting at

Pondicherry end 230 kV Pondicherry – Villianur and 230 kV

Pondicherry – Bahour line, and set them appropriately to achieve

required time-coordination with O/C protections of ICT’s at Villianur

SS.

3. NLCIL to keep DEF protection in blocked condition as long as

Distance Protection is active, and configure it to become active only

when distance protection does not pickup to avoid time-

coordination issues.

Yet to be informed

Pending

PendingYet to be informed

57/II/9 Tripping of 400 kV Nellore (PG) - NPS

line-1, 400 kV Krishnapatnam-Nellore

(AP) lines -1&2 and 400kV NPS -

MEPL line

18-07-2016 at

19:05 hrs

Triggering incident was snapping of Y phase

conductor in 400kV Nellore (PG) - NPS line-1.

Distance relay at Krishnapatnam end over-reached in

Zone-1, and resulted in tripping of 400kV

Krishnapatnam – Nellore (AP) lines - 1&2 from

Krishnapatnam end. Distance relay at MEPL over-

reached and resulted in tripping of MEPL-NPS line

from MEPL end.

PGCIL (SR-I), TPCIL, MEPL, SEL, SGPL, APTRANSCO,

APGENCO and SDSTPS to implement line differential protection on

all 400 kV transmission lines (of length less than 50 km) emanating

from Nellore PS, Nellore (PG) SS, and Nellore (AP) SS. [It may be

noted here that the cut-off length of 50 km has been specified with a

view to exclude only long transmission lines].

APGENCO/ PGCIL(SR-

I)/ TPCIL/MEPL/

SEL/SGPL/

APTRANSCO

56/IV/2 Tripping of 400 kV VTPS-Suryapet line Direct Trip was received at VTPS and line was

holding from Suryapet end

13-06-2016 at

16:55 hrs

APGENCO/

TSTRANSCO

1. TANTRANSCO and PGCIL (SR-II) to take steps to complete

insulator replacement works on the 400 kV lines owned by them in

Chennai area within 3 months.

1. JSWEL to follow file naming terminology provided by SRPC

for various tripping files uploaded in SRLDC’s TMS portal.

2.JSWEL to furnish reasons for AR-BLOCK observed during

the instant tripping and remedial action taken by them to

keep A/R in service.

3. KPCL to configure DR & EL properly to record OVR Stage-I

& Stage-II protections at their BTPS station.

14-03-2017 at

19:11 hrs

Tripping of 400 kV YTPS-BTPS line and

400 kV BTPS-JSWEL line

KPCL/JSWEL Yet to be informed Pending


APGENCO in coordination with TSTRANSCO:

1.End-to-end communication for DT/ permissive & other signals may


2.Healthiness of PLCC system components (hardware and software)


replaced.

Status received vide TANTRANSCO mail dated 15-06-2017 &

04.08.2017:

1. All the Porcelain insulators of 400kV NCTPS-II - Vallur feeders-1&2

were replaced with Polymer insulators by 20.05.2017.

2. Existing Porcelain insulators of all other 400kV feeders are being

replaced with Polymer insulators in a phased manner.

TANTRANSCO/

PGCIL(SR-II)

Pending

63/II.9

57/I/1 Complete outage of 220 kV Karwar

Substation of KPTCL

KPTCL/ KPCL/ NPCIL

(KAPS)

NPCIL(KGS) mail dated on 03-12-2016:

A.The 200 ms Definite time DEFR element in both Kaiga Kadra and

Kaiga Kodasally lines were disabled. IDMT DEFR is retained .

B. The 200 ms Definite time back up o/c element in both Kaiga Kadra and

Kaiga Kodasally lines were disabled. IDMT is retained.

------Completed


Issue was addressed to the concerned for necessary action.


Meeting was conducted and the relays procurement for all the locations is

under progress.

Pending

12-07-2017 at

11:36 hrs

Triggering incident was failure of R phase PT in Bus-

1 at 220kV Karwar substation. 220kV Kaiga-

Kodasalli tripped during the incident. Also bus shut

down occurred at Kadra and Kodasally stations.

1.NPCIL (KAPS) to disable DefiniteTime O/C relay, and put in its

place by IDMT O/C relay for backup protection on both 220 kV

Kaiga – Kadra line and 220 kV Kaiga – Kodasalli line at Kaiga end.

2.KPTCL to put bus bar protection in service at their 220 kV Karwar

SS at the earliest.

3.KPCL/ KPTCL to implement Weak In-feed Logic with Echo feature

enabled by Under Voltage (27) element on Kadra – Karwar lines 1 &

2.

4.KPTCL to furnish equipment failure report of the current incident to

PSE&TD Division of CEA with a copy marked to SRPC.

Annexure-II

Page 31 of 33

65/II/5 Tripping of 400 kV Ghanapur-

Mamidapalli line

08-05-2017 at

19:15 hrs

Line tripped at Ghanapur end only and was holding

from Mamidapalli. Ghanapur end protection had

sensed R-phase to earth fault


by TSTRANSCO in coordination with PGCIL (SR-I):

1. End-to-end communication for DT/ permissive & other signals


2. Healthiness of PLCC system components (hardware and

software) at both ends shall be checked and faulty components

shall be repaired/ replaced.

TSTRANSCO/ PGCIL

(SR-I)


65/III/12 Tripping of 400 kV Srisailam-Dindi line-2 24-05-2017

at 15:02 hrs

R-phase to earth fault. Auto-reclose was successful

at Dindi and Zone - 1, 3-phase trip at Srisailam

Since all 400 kV lnies emanating from Srisailam LB are composite

feeders, APTRANSCO/ TSTRANSCO can keep A/R functionality

disabled at respective remote end stations under their control.

APTRANSCO/ TSTRANSCO Yet to be informed Pending

66/ II/ 5 Tripping of 400 kV Ramagundam -

Dichipally line, 400kV Nizamabad -

Dichipally line-1 and 400/220 kV ICT-1

05-06-2017 at

19:15 hrs

Triggering incident was fault in 400kV Nizamabad

GIS

1. TSTRANSCO/ NTPC to adopt proper Zone-2 time settings (say,

Ramagundam end � 500 msec; Dichipally end � 350 msec in line

with Ramakrishna Committee recommendations) on 400 kV

Ramagundam – Dichipally line and 400 kV Dichipally - Nizamabad

lines respectively.

2. For the 400 kV Dichipally - Nizamabad D/C line, TSTRANSCO, in

coordination with PGCIL (SR-I), to carry out the following:



(ii) Healthiness of PLCC system components (hardware and



NTPC-Ramagundam/

TSTRANSCO/ PGCIL (SR-I)


66/ II/ 8 Tripping of 400 kV Khammam – KTPS

lines – 1 & 2

08-06-2017 at

18:32 hrs

Lines – 1 & 2 tripped on B-phase to earth faults 1. TSGENCO to keep uniform A/R dead-time of 1 sec on the lines

emanating from their KPTS station.

2. PGCIL (SR-I) to enable Trip-on-Reclose (TOR) functionality for

Zone-2 faults for Khammam – KTPS lines at Khammam end, if such a

feature is available in the concerned relay, and to configure it for

sending Direct Trip (DT) Command to KTPS end.

TSGENCO/

PGCIL (SR-I)


65/I/2 Complete outage of 400kV Uravakonda

and Jammalamadugu Substations

31-05-2017 at

17.44 hrs

Triggering incident was tripping of 400 kV Kurnool-

PG - Narnoor line - 1 & 2 and 400 kV Narnoor-

Jamalamadugu line-2 which led to loss of supply to

400kV Uravakonda and Jamalamadugu. 400kV Gooty-

Narnoor, 400kV Narnoor-Jamalamadugu-1, 400kV

Srisailam-Narnoor, 400kV Uruvakonda-

Mahboobnagar-1&2 were out of service in

antecedent condition.

1. For 400 kV Ghani –Narnoor line, the following shall be carried out

by APTRANSCO:






2. PGCIL (SR-II) to take appropriate action w.r.t disabling non-

directional instantaneous I>4 protection that operates without

checking existence of stub. If required, the issue may be referred to

relays OEM for appropriate solution or the present relays may be

replaced with other relays with different styles that don’t have the

issue observed.

APTRANSCO/ PGCIL

(SR-II)


Y-phase to earth fault. Neyveli TS2 end relay issued a

3-phase trip 220ms after issue of Y phase trip. Direct

Trip was sent to Pugalur end preventing auto-

reclose.

07-05-2017

at 19:55 hrs

PGCIL (SR-II)/ NLCIL Yet to be informed Pending

65/II/16 Tripping of 400 kV Kayathar-Karaikudi

line

25-05-2017 at

15:52 hrs

R-phase to earth fault had occurred in line. There

was Zone-2, 3 phase trip operation at Kayathar end

and Zone-1, 3 phase trip at Karaikudi end


by TANTRANSCO in coordination with PGCIL (SR-II):



2. Healthiness of PLCC system components (hardware and software)


repaired/ replaced.

PGCIL (SR-II)/

TANTRANSCO

Status received vide TANTRANSCO mail dated 04-08-

2017:

1. End to end communication for DT & other signals will be carried out in

coordination with PGCIL (SR-II).

2. PLCC system components at Kayathar end will be checked for

healthiness.

Pending


by TSTRANSCO in coordination with NTPC-Ramagundam:





repaired/ replaced.

Over Voltage Stage-1 had operated at Gajwel end.

Ramagundam end did not trip as Direct Trip was not

received from Gajwel end.

29-05-2017

at 00:07 hrs


Gajwel line

65/II/19 TSTRANSCO/ NTPC

(Ramagundam)


Tripping of 400 kV Neyveli TS2-Pugalur

line

65/III/6 For the line under consideration, the following shall be carried out

by NLCIL in coordination with PGCIL (SR-II):





repaired/ replaced.

Annexure-II

Page 32 of 33

66/ II/ 10 Tripping of 400/ 220 kV ICT’s – 3 & 4 at

Ramagundam STPS

11-06-2017

at 19:46hrs

Triggering incident was failure of 220 kV

B-phase LA in ICT-3 LV extension feeder (220KV line-

2) at Malayalapalli substation

1. NTPC to disable high-set of DEFR on the 220 kV lines emanating

from their Ramagundam STPS.

2. NTPC/ TSTRANSCO to provide Line Differential Protection (with or

without pilot) on 220 kV Ramagundam – Malayalapalli lines – 1 & 2

& 3.

NTPC-Ramagundam/

TSTRANSCO


66/ IV/ 1 Tripping of 400 kV Vijayawada-Vemagiri

line-2

03-06-2017

at 16:09 hrs

Breakers at Vemagiri end tripped due to receipt of

Direct Trip and line was holding from Vijayawada

end.

PGCIL (SR-I)/ APTRANSCO to rectify DC leakage issues for the

APTRANSCO bays at Vijayawada SS, and ensure that PLCC carrier

communication is maintained healthy.

PGCIL (SR-I)/

APTRANSCO


sending Direct Trip (DT) Command to KTPS end.

3. PGCIL (SR-I) to set right time-sync issues w.r.t. Khammam end

Event Loggers on Khammam – KTPS lines.

4. For 400 kV Khammam – KTPS line-1, PGCIL (SR-I), in coordination

with TSGENCO, shall carry out the following:






66/ IV/ 3 Tripping of 400 kV Vijayawada-VTPS line 07-06-2017

at 23:55 hrs

Line was holding from VTPS end and breaker at

Vijayawada end tripped on Direct Trip receipt.

For the line under consideration, APTRANSCO/ APGENCO, in

coordination with PGCIL (SR-I) to carry out the following:






APGENCO/ APTRANSCO/

PGCIL (SR-I)


Annexure-II

Page 33 of 33

Sl.No. Element NameOutage

date/time

Revival

date/timeReason for Outage Sender/ Receiver Remedial Measures/ Actions taken

1 400 kV KAIGA - GUTTUR 1 06-02-2017/05:01:00 POLE DISCREPANCY NPCIL/ KPTCL

KGS:

The line tripped due to unsuccessful A/R and operation

of PDR at KGS end. The line was taken into service vide

CPCC-CP-02/110 and SRLDC-CR-02/154 codes.

2 400 kV KAIGA - GUTTUR 1 27-03-2017/15:38:00 27-03-2017/16:48:00 RELAY MALOPERATION NPCIL (KGS)/ KPTCL

KPTCL:

At Guttur end DPR operated in Z1, R phase, AR

unsucessful due to persistant fault. At Kaiga end DPR

operated in Zone-1, RN fault,145km; AR attempt is

observed from Kaiga end.

Reason: Transient fault. Stood OK after test charging.

KGS:

3 400 kV KHAMMAM - MAMIDIPALLY 2 08-05-2017/16:06:00 08-05-2017/17:49:00 R PHASE TO GROUND FAULTPGCIL (SR-I)/ TSTRANSCO/

APTRANSCO

PGCIL(SR-I):Tripped on operation of distance

protection. Line belongs to APTRANSCO.

TSTRANSCO: Tripped at both ends. Tripped on R-phase

to ground, Zone-1 indications, A/R acted and was

unsucessful at Mamidipally end.

APTRANSCO:

4 400 Kv VTPS - MALKARAM 1 22-05-2017/14:52:00 22-05-2017/18:58:00 B phase fault APGENCO/ TSTRANSCO

TSTRANSCO:

Trippedat both ends. Tripped on B-Phase to ground

and Zone-1 indications, A/R acted and was unsucessful

at Malkaram end.

5HVDC TALCHER - KOLAR POLE 1 AT

TALCHER01-06-2017/23:22:00 02-06-2017/00:11:00

DC DIFFERENTIAL PROTECTION

OPERATEDPGCIL (SR-II)/ PGCIL (ER-I)

PGCIL(SR-II):

Due to DC filter Diff relay operation at Talcher end

6 400 kV KOLAR - HOODY 2 06-06-2017/20:08:00 DUE TO HEAVY WIND PGCIL (SR-II)/ KPTCL

PGCIL (SR-2):

Hand Tripped due to Isolator problem at Hoody End

7400 kV PUGALUR -

KALAIVANTHAPATTU14-06-2017/12:37:00 14-06-2017/18:45:00 TRIPPED ON Y-N FAULT PGCIL(SR-II)

To-be-discussed

8 400 kV KAIGA - NARENDRA 2 07-07-2017/07:50:00 07-07-2017/09:08:00 TRIPPED ON R-Y Ph FAULT NPCIL / KPTCLTo-be-discussed

9 220 kV AMBEWADI - PONDA 1 16-07-2017/11:38:00 16-07-2017/12:08:00 DISTANCE PROTECTION KPTCL / GEDTo-be-discussed

Pending Remedial Measures/ Actions taken

for the Critical Tripping Incidents (as on 06.09.2017)

Annexure-III

Page 1 of 4

10 220 kV AMBEWADI - PONDA 2 20-07-2017/01:36:00 LINE FAULT KPTCL/ GEDTo-be-discussed

11 HVDC BHADRAVATHI POLE 1 21-07-2017/22:48:00 21-07-2017/23:53:00 INTERNAL MINOR ALARM PGCIL (SR-I)/ PGCIL (WR-I)To-be-discussed

12 400 KV GOOTY - TUMKUR - 1 22-07-2017/15:07:00 22-07-2017/15:45:00TRIPPED DURING OPGW

WORKSPGCIL (SR-I)/ PGCIL (SR-II)

To-be-discussed

13 400 Kv GAJWEL - BHOOPALAPALLY 2 22-07-2017/13:13:00 22-07-2017/13:36:00 B PHASE FAULT TSTRANSCO/ TSGENCO

TSTRANSCO: T

ripped at Both ends. Tripped on B-Phase to Ground and

Zone-1 indication at Gajwel end. Bhoopalapally end

auto reclosure acted and reclosed. Auto reclosure did

not act at Gajwel end. Non operation of Auto reclosure

at Gajwel end will be checked duly taking Line

Clearance on the feeder.

14 400 kV GUTTUR - HIRIYUR 2 22-07-2017/15:03:00 22-07-2017/15:53:00TRIPPED DUE TO RELAY MAL

OPERATIONKPTCL/ PGCIL (SR-II)

To-be-discussed

15 400 kV HASSAN - NEELAMANGALA 1 27-07-2017/17:00:00 TRIPPED DUE TO Y-N FAULT PGCIL(SR-II)/ KPTCLTo-be-discussed

16 400 kV KAIGA - GUTTUR 1 29-07-2017/13:21:00 29-07-2017/18:52:00TRIPPED DUE TO DISTANCE

RELAY MALOPERATIONNPCIL (KGS)/ KPTCL

To-be-discussed

17 400kV VTPS -MALKARAM 29-07-2017/19:33:00BUS BAR PROTECTION ACTED

DUE TO CT BLAST AT VTPSAPGENCO/ TSTRANSCO

TSTRANSCO: Tripped at both ends. Tripped on Direct

trip received indications at Malkaram end as Bus bar

acted at VTPS end due to blasting of Y Phase CT of

Malkaram feeder.

APGENCO:

18 400KV VTPS-SURYAPET 29-07-2017/19:33:00

BUS BAR PROTECTION

OPERATED DUE TO CT BLAST

AT VTPS

APGENCO/ TSTRANSCO

TSTRANSCO: Tripped at VTPS end only on Over Voltage

due to blasting of Y Phase CT of Malkaram feeder

(which is in same dia of Suryapet feeder). But as Direct

Trip was not received from VTPS end line did not trip at

Suryapet end.

APGENCO:

19 HVDC GAJUWAKA POLE 1 03-08-2017/12:16:00 03-08-2017/13:08:00 VALVE FAILURE PGCIL (SR-I)To-be-discussed

20 400 kV NEYVELI TS 2- SALEM 1 06-08-2017/17:04:00 06-08-2017/17:25:00 TRIPPED ON Y-N fault NLCIL / PGCIL (SR-II)To-be-discussed

21 400 kV CUDDAPAH - N P KUNTA 07-08-2017/12:20:00 07-08-2017/13:33:00 TRIPPED DUE TO R-N FAULT PGCIL (SR-I)To-be-discussed

22 400 KV NIZAMABAD- DICHPALLY-2 07-08-2017/17:12:00 07-08-2017/18:03:00 DT received at Dchipally end PGCIL (SR-I) / TSTRANSCO

TSTRANSCO: Tripped at Dichpally end only as Direct Trip

was received from Nizamabad end and there is counter

increment in PLCC Panel.

PGCIL(SR-I):

Annexure-III

Page 2 of 4

23 400 kV N'SAGAR - CUDDAPPA 1 07-08-2017/12:20:00 07-08-2017/13:31:00 TRIPPED DUE TO R-N FAULT PGCIL(SR-I)To-be-discussed

24765 KV NIZAMABAD -

MAHESHWARAM - 207-08-2017/00:16:00 07-08-2017/15:56:00 R-N FAULT PGCIL (SR-I)

To-be-discussed

25765 KV NIZAMABAD -

MAHESHWARAM - 207-08-2017/00:16:00 R-N FAULT PGCIL (SR-I)

To-be-discussed

26 400 Kv COASTAL - TTRNPS 09-08-2017/17:54:00 09-08-2017/18:11:00 RELAY MALOPERATION CEPL/ TANGEDCOTo-be-discussed

27 400 kV COASTAL - TTRNPS 2 09-08-2017/17:54:00 09-08-2017/18:40:00 RELAY MALOPERATION CEPL/ TANGEDCOTo-be-discussed

28 400 KV KUDGI PG - TUMKUR - 2 09-08-2017/14:13:00 09-08-2017/14:23:00 RELAY MALOPERATION PGCIL (SR-II)To-be-discussed

29 220 kV YERANDAHALLY - HOSUR 14-08-2017/11:35:00 14-08-2017/12:00:00TRIPPED DUE TO JUMPER AT

TOWER OPENEDKPTCL/ TANTRANSCO

TANTRANSCO: Temporary fault

30 220 kV PALAKKAD - KANJIKODE 2 14-08-2017/10:58:00 14-08-2017/14:24:00HOTSPOT IN CT TERMINAL

WORKKSEB

To-be-discussed

31 400 Kv BANGALORE - BIDADI 2 15-08-2017/03:15:00 15-08-2017/03:54:00 B-N FAULT PGCIL(SR-II)To-be-discussed

32 400 kV KALPAKKA - GAZUWAKA 2 16-08-2017/14:40:00 16-08-2017/14:53:00 DISTANCE PROTECTION APTRANSCO/ PGCIL(SR-I)To-be-discussed

33 400 kV KALPAKKA - GAZUWAKA 1 16-08-2017/14:40:00 16-08-2017/14:53:00 DISTANCE PROTECTION APTRANSCO/ PGCIL(SR-I)To-be-discussed

34 400/220 kV ICT-3 AT N'SAGAR 22-08-2017/10:21:00 22-08-2017/10:28:00TRIIPEED DUE TO RELAY

MALOPERATIONPGCIL(SR-I)

To-be-discussed

35 220 kV AMBEWADI - PONDA 2 22-08-2017/13:09:00 22-08-2017/14:02:00 EARTH FAULT relay operated KPTCL/ GED (WR)To-be-discussed

36 400 KV GOOTY - TUMKUR - 1 23-08-2017/11:44:00 23-08-2017/13:00:00 PHASE TO PHASE FAULT PGCIL(SR-II)To-be-discussed

37 400 kV MAHESHWARAM - NARNOOR 30-08-2017/10:11:00 30-08-2017/10:25:00 RELAY MALOPERATION PGCIL (SR-I)/ APTRANSCOTo-be-discussed

38 400/220 kV ICT-2 AT NELLORE 31-08-2017/05:05:00 31-08-2017/17:06:00 MOLOPERATION APTRANSCOTo-be-discussed

39 400kV KANARPETTY-TIRUNELVELI 31-08-2017/21:58:00 31-08-2017/23:03:00 TRIPPED ON R-N FAULT TANTRANSCO/ PGCIL (SR-II)To-be-discussed

40 400 kV MYSORE - KOZHIKODE 1 01-09-2017/16:28:00 01-09-2017/16:43:00 TRIPPED ON Transient fault PGCIL (SR-II)To-be-discussed

41 220 kV AMBEWADI - PONDA 1 01-09-2017/13:25:00 01-09-2017/13:54:00 DISTANCE PROTECTION KPTCL/ GEDTo-be-discussed

Annexure-III

Page 3 of 4

42 400 Kv NCTPS - SVCTM-II 01-09-2017/06:46:00 01-09-2017/17:09:00 B-N FAULT TANGEDCO/ TANTRANSCOTo-be-discussed

43 400/110 kV ICT 2 AT ALAMATHY 02-09-2017/16:04:00 02-09-2017/17:36:00 DIFFERENTIAL PROTECTION TANTRANSCOTo-be-discussed

44 400 Kv NELLORE - SPDR-1 03-09-2017/18:29:00TRIPPED ON B PHASE TO

GROUND FAULTPGCIL (SR-I)/ PGCIL (SR-II)

To-be-discussed

45 400kV KHAMAM - WARANGAL 03-09-2017/09:49:00 03-09-2017/11:52:00TRIPPED ON PRD MAL

OPERATIONPGCIL (SR-I)

To-be-discussed

46 220 kV AMBEWADI - PONDA 1 03-09-2017/12:53:00 03-09-2017/13:06:00 B-n fault KPTCL/ GEDTo-be-discussed

Annexure-III

Page 4 of 4

From Bus

NumberFrom Bus Name

To Bus

NumberTo Bus Name Ckt Id

Length,

km

Charging

'B' (pu)

Q' from

Line (B/2)

[= Q1]

Q' from Line

Reactor

[= Q2]

Net 'Q' from

Line

[= Q1 + Q2]

Power

Flow, MW

Order as

per

Criticality

New OVR

Grading (at

FROM BUS

end)

414010 KURNOOL 400.00 414001 GOOTY 400.00 1 84.19 0.4695 0.23475 0 0.23475 445.1 9 A

414010 KURNOOL 400.00 414031 KURNOOL-PG 400.00 1 9.88 0.07243 0.036215 0 0.036215 303.9 10 A

414010 KURNOOL 400.00 414031 KURNOOL-PG 400.00 2 9.88 0.07243 0.036215 0 0.036215 303.9 7 C

414010 KURNOOL 400.00 414036 JAMALAMADUGU400.00 1 100.86 0.73929 0.369645 0 0.369645 -35.9 5 E

414010 KURNOOL 400.00 414036 JAMALAMADUGU400.00 2 100.86 0.73929 0.369645 0 0.369645 -35.9 1 I

414010 KURNOOL 400.00 414041 GHANI 400.00 1 16.26 0.11919 0.059595 0 0.059595 -273.9 8 B

414010 KURNOOL 400.00 414041 GHANI 400.00 2 16.26 0.11919 0.059595 0 0.059595 -273.9 4 F

414010 KURNOOL 400.00 424003 GHANAPUR 400.00 1 226.5 1.2571 0.62855 0 0.62855 -163.7 2 H

414010 KURNOOL 400.00 424005 SRISAILAMLB 400.00 1 104.9 0.5749 0.28745 0 0.28745 -306.9 6 D

414010 KURNOOL 400.00 424021 MHSWRM-PG 400.00 1 175.01 0.97131 0.485655 0 0.485655 -331 3 G

414011 KALPAKKA 400.00 414009 GAZUWAKA 400.00 1 3.39 0.02061 0.010305 0 0.010305 -328.1 9 B

414011 KALPAKKA 400.00 414009 GAZUWAKA 400.00 2 3.39 0.02061 0.010305 0 0.010305 -328.1 6 D

414011 KALPAKKA 400.00 414012 SIMHADRI-I 400.00 1 3.72 0.02256 0.01128 0 0.01128 -345.4 12 A

414011 KALPAKKA 400.00 414012 SIMHADRI-I 400.00 2 3.72 0.02256 0.01128 0 0.01128 -345.4 10 B

414011 KALPAKKA 400.00 414012 SIMHADRI-I 400.00 3 3.72 0.02256 0.01128 0 0.01128 -345.4 7 D

Revised OVR Grading Studies for certain 400 kV Transmission Lines of Southern Region

1. Voltage - Time (OVR) Grading Matrix:

2. Study Results:

Annexure-IV (OVR-Studies)

Page 1 of 4

414011 KALPAKKA 400.00 414012 SIMHADRI-I 400.00 4 3.72 0.02256 0.01128 0 0.01128 -345.4 3 G

414011 KALPAKKA 400.00 414014 VEMAGIRI 400.00 1 166.93 1.0124 0.5062 0 0.5062 281.7 11 A

414011 KALPAKKA 400.00 414014 VEMAGIRI 400.00 2 166.93 1.0124 0.5062 0 0.5062 281.7 2 H

414011 KALPAKKA 400.00 414027 HINDUJA 400.00 1 7.35 0.04425 0.022125 0 0.022125 211.8 8 C

414011 KALPAKKA 400.00 414027 HINDUJA 400.00 2 7.35 0.04425 0.022125 0 0.022125 211.8 5 E

414011 KALPAKKA 400.00 424004 KHAMMAM 400.00 1 364 2.2076 1.1038 -0.5714 0.5324 152.3 1 I

414011 KALPAKKA 400.00 424020 ASUPAKA 400.00 1 131.07 1.60744 0.80372 -0.5714 0.23232 138.4 4 F

414042 K V KOTA 400.00 414027 HINDUJA 400.00 1 246 1.48092 0.74046 0 0.74046 -211.7 3 B

414042 K V KOTA 400.00 414027 HINDUJA 400.00 2 246 1.48092 0.74046 0 0.74046 -211.7 1 G

414042 K V KOTA 400.00 424016 SURYAPET 400.00 1 174.54 1.27938 0.63969 0 0.63969 122.6 4 A

414042 K V KOTA 400.00 424016 SURYAPET 400.00 2 174.54 1.27938 0.63969 0 0.63969 122.6 2 D

424003 GHANAPUR 400.00 414007 TALLAPALLI 400.00 1 155.26 0.86172 0.43086 0 0.43086 65.9 2 G

424003 GHANAPUR 400.00 414010 KURNOOL 400.00 1 226.5 1.2571 0.62855 0 0.62855 163.7 1 H

424003 GHANAPUR 400.00 424002 RSTPS NTPC 400.00 1 201.25 1.11694 0.55847 0 0.55847 -353.6 6 B

424003 GHANAPUR 400.00 424002 RSTPS NTPC 400.00 2 201.25 1.11694 0.55847 0 0.55847 -353.6 3 E

424003 GHANAPUR 400.00 424006 MAMIDIPALLI 400.00 1 46 0.2769 0.13845 0 0.13845 292.9 4 D

424003 GHANAPUR 400.00 424008 GAJWEL 400.00 1 72.95 0.4392 0.2196 -0.45351 -0.23391 -493.8 8 A

424003 GHANAPUR 400.00 424011 MALKARAM 400.00 1 54.9 0.3254 0.1627 -0.4535 -0.2908 134.6 7 A

424003 GHANAPUR 400.00 424021 MHSWRM-PG 400.00 1 56.15 0.31166 0.15583 0 0.15583 -361.1 5 C

424004 KHAMMAM 400.00 414007 TALLAPALLI 400.00 1 144.58 0.80242 0.40121 0 0.40121 160.8 8 C

424004 KHAMMAM 400.00 414007 TALLAPALLI 400.00 2 144.58 0.86938 0.43469 0 0.43469 173.5 4 F

424004 KHAMMAM 400.00 414007 TALLAPALLI 400.00 3 144.58 0.86938 0.43469 0 0.43469 173.5 2 H

424004 KHAMMAM 400.00 414008 NUNNA 400.00 1 114.78 0.637 0.3185 0 0.3185 170.2 5 E

424004 KHAMMAM 400.00 414011 KALPAKKA 400.00 1 364 2.2076 1.1038 -0.5714 0.5324 -152.3 3 G

424004 KHAMMAM 400.00 424006 MAMIDIPALLI 400.00 1 198 1.192 0.596 0 0.596 147.9 7 D

424004 KHAMMAM 400.00 424006 MAMIDIPALLI 400.00 2 198 1.192 0.596 0 0.596 147.9 1 I

424004 KHAMMAM 400.00 424010 WARANGAL 400.00 1 117.09 0.64985 0.324925 -0.4535 -0.128575 -280.4 10 A

424004 KHAMMAM 400.00 424012 KTPS-VI 400.00 1 67.76 0.4079 0.20395 0 0.20395 -281.3 9 B

424004 KHAMMAM 400.00 424012 KTPS-VI 400.00 2 67.76 0.4079 0.20395 0 0.20395 -281.3 6 D

424004 KHAMMAM 400.00 424020 ASUPAKA 400.00 1 131.07 0.78872 0.39436 -0.5714 -0.17704 -136.9 11 A

424006 MAMIDIPALLI 400.00 424003 GHANAPUR 400.00 1 46 0.2769 0.13845 0 0.13845 -292.9 5 A

424006 MAMIDIPALLI 400.00 424004 KHAMMAM 400.00 1 198 1.192 0.596 0 0.596 -147.9 3 D

424006 MAMIDIPALLI 400.00 424004 KHAMMAM 400.00 2 198 1.192 0.596 0 0.596 -147.9 1 G

424006 MAMIDIPALLI 400.00 424019 DINDI 400.00 1 74.91 0.41576 0.20788 0 0.20788 -49.8 4 B

424006 MAMIDIPALLI 400.00 424019 DINDI 400.00 2 74.91 0.41576 0.20788 0 0.20788 -49.8 2 E

424013 SHANKARPALLI400.00 424008 GAJWEL 400.00 1 105 0.58275 0.291375 0 0.291375 -280.1 4 D


Page 2 of 4

424013 SHANKARPALLI400.00 424016 SURYAPET 400.00 1 231 1.39062 0.69531 0 0.69531 32.8 3 E

424013 SHANKARPALLI400.00 424016 SURYAPET 400.00 2 231 1.39062 0.69531 0 0.69531 32.8 1 H

424013 SHANKARPALLI400.00 424017 NARSARPUR 400.00 1 60.92 0.33811 0.169055 0 0.169055 -265 6 A

424013 SHANKARPALLI400.00 424022 MAHES-TS 400.00 1 83.99 0.5056 0.2528 0 0.2528 -178.3 5 B

424013 SHANKARPALLI400.00 424022 MAHES-TS 400.00 2 83.99 0.5056 0.2528 0 0.2528 -178.3 2 G

424016 SURYAPET 400.00 414013 VTS-IV 400.00 2 130.95 0.72645 0.363225 0 0.363225 37.9 5 B

424016 SURYAPET 400.00 414042 K V KOTA 400.00 1 174.54 1.27938 0.63969 0 0.63969 -122.6 6 A

424016 SURYAPET 400.00 414042 K V KOTA 400.00 2 174.54 1.27938 0.63969 0 0.63969 -122.6 2 G

424016 SURYAPET 400.00 424011 MALKARAM 400.00 1 135.56 0.8157 0.40785 0 0.40785 51.9 3 E

424016 SURYAPET 400.00 424013 SHANKARPALLI400.00 1 231 1.39062 0.69531 0 0.69531 -32.8 4 D

424016 SURYAPET 400.00 424013 SHANKARPALLI400.00 2 231 1.39062 0.69531 0 0.69531 -32.8 1 H

424019 DINDI 400.00 424005 SRISAILAMLB 400.00 1 73.02 0.40527 0.202635 0 0.202635 -50 4 A

424019 DINDI 400.00 424005 SRISAILAMLB 400.00 2 73.02 0.40527 0.202635 0 0.202635 -50 2 D

424019 DINDI 400.00 424006 MAMIDIPALLI 400.00 1 74.91 0.41576 0.20788 0 0.20788 49.8 3 B

424019 DINDI 400.00 424006 MAMIDIPALLI 400.00 2 74.91 0.41576 0.20788 0 0.20788 49.8 1 G

424020 ASUPAKA 400.00 414011 KALPAKKA 400.00 1 131.07 1.60744 0.80372 0 0.80372 -138.4 1 D

424020 ASUPAKA 400.00 424004 KHAMMAM 400.00 1 131.07 0.78872 0.39436 0 0.39436 136.9 2 A

424021 MHSWRM-PG 400.00 414010 KURNOOL 400.00 1 175.01 0.97131 0.485655 0 0.485655 331 1 F

424021 MHSWRM-PG 400.00 424003 GHANAPUR 400.00 1 56.15 0.31166 0.15583 0 0.15583 361.1 2 D

424021 MHSWRM-PG 400.00 424022 MAHES-TS 400.00 1 1.55 0.01132 0.00566 0 0.00566 410.8 3 B

424021 MHSWRM-PG 400.00 424022 MAHES-TS 400.00 2 1.55 0.01099 0.005495 0 0.005495 423.1 4 A

424022 MAHES-TS 400.00 424013 SHANKARPALLI400.00 1 83.99 0.5056 0.2528 0 0.2528 178.3 3 B

424022 MAHES-TS 400.00 424013 SHANKARPALLI400.00 2 83.99 0.5056 0.2528 0 0.2528 178.3 1 F

424022 MAHES-TS 400.00 424021 MHSWRM-PG 400.00 1 1.55 0.01132 0.00566 0 0.00566 -410.8 4 A

424022 MAHES-TS 400.00 424021 MHSWRM-PG 400.00 2 1.55 0.01099 0.005495 0 0.005495 -423.1 2 D


Page 3 of 4

From Bus

NumberFrom Bus Name

To Bus

NumberTo Bus Name Ckt Id

Length,

km

Charging 'B'

(pu)

Q' from

Line (B/2)

[= Q1]

Q' from

Line

Reactor

[= Q2]

Net 'Q'

from Line

[= Q1 +

Q2]

Power

Flow, MW

Order as

per

Criticality

New OVR

Grading (at

FROM BUS

end)

337003 WARDHA-PG 765.00 427001 NIZAMABAD 765.00 1 291.2 7.74592 3.87296 -2.4 1.47296 755.32 A

337003 WARDHA-PG 765.00 427001 NIZAMABAD 765.00 2 291.2 7.74592 3.87296 -2.4 1.47296 755.31 E

427001 NIZAMABAD 765.00 337003 WARDHA-PG 765.00 1 291.2 7.74592 3.87296 -2.4 1.47296 -755.33 B

427001 NIZAMABAD 765.00 337003 WARDHA-PG 765.00 2 291.2 7.74592 3.87296 -2.4 1.47296 -755.31 E

427001 NIZAMABAD 765.00 427002 MHSWRM 765.00 1 240 6.4651 3.23255 -2.4 0.83255 635.82 C

427001 NIZAMABAD 765.00 427002 MHSWRM 765.00 2 240 0.01099 0.005495 -2.4 -2.394505 635.84 A

427002 MHSWRM 765.00 427001 NIZAMABAD 765.00 1 240 6.4651 3.23255 -2.4 0.83255 -635.82 A

427002 MHSWRM 765.00 427001 NIZAMABAD 765.00 2 240 0.01099 0.005495 -2.4 -2.394505 -635.81 E

Revised OVR Grading Studies for certain 765 kV Transmission Lines of Southern Region


2. Study Results:


Page 4 of 4

From Bus

NumberFrom Bus Name

To Bus

NumberTo Bus Name Ckt Id Length, km

Line Reactor VARS

at FROM BUS End

(pu)

New OVR Grading

(at FROM BUS end)

414010 KURNOOL 400.00 414001 GOOTY 400.00 1 84.19 0A

414010 KURNOOL 400.00 414031 KURNOOL-PG 400.00 1 9.88 0A

414010 KURNOOL 400.00 414031 KURNOOL-PG 400.00 2 9.88 0C

414010 KURNOOL 400.00 414036 JAMALAMADUGU400.00 1 100.86 0E

414010 KURNOOL 400.00 414036 JAMALAMADUGU400.00 2 100.86 0I

414010 KURNOOL 400.00 414041 GHANI 400.00 1 16.26 0B


2. Over Voltage Relay Gradings:

Revised OVR Gradings for certain 400 kV Transmission Lines of Southern Region

Annexure-V (OVR-Gradings)

Page 1 of 5

414010 KURNOOL 400.00 414041 GHANI 400.00 2 16.26 0F

414010 KURNOOL 400.00 424003 GHANAPUR 400.00 1 226.5 0H

414010 KURNOOL 400.00 424005 SRISAILAMLB 400.00 1 104.9 0D

414010 KURNOOL 400.00 424021 MHSWRM-PG 400.00 1 175.01 0G

414011 KALPAKKA 400.00 414009 GAZUWAKA 400.00 1 3.39 0B

414011 KALPAKKA 400.00 414009 GAZUWAKA 400.00 2 3.39 0D

414011 KALPAKKA 400.00 414012 SIMHADRI-I 400.00 1 3.72 0A

414011 KALPAKKA 400.00 414012 SIMHADRI-I 400.00 2 3.72 0B

414011 KALPAKKA 400.00 414012 SIMHADRI-I 400.00 3 3.72 0D

414011 KALPAKKA 400.00 414012 SIMHADRI-I 400.00 4 3.72 0G

414011 KALPAKKA 400.00 414014 VEMAGIRI 400.00 1 166.93 0A

414011 KALPAKKA 400.00 414014 VEMAGIRI 400.00 2 166.93 0H

414011 KALPAKKA 400.00 414027 HINDUJA 400.00 1 7.35 0C

414011 KALPAKKA 400.00 414027 HINDUJA 400.00 2 7.35 0E

414011 KALPAKKA 400.00 424004 KHAMMAM 400.00 1 364 -0.5714I

414011 KALPAKKA 400.00 424020 ASUPAKA 400.00 1 131.07 -0.5714F

414042 K V KOTA 400.00 414027 HINDUJA 400.00 1 246 0B

414042 K V KOTA 400.00 414027 HINDUJA 400.00 2 246 0G

414042 K V KOTA 400.00 424016 SURYAPET 400.00 1 174.54 0A

414042 K V KOTA 400.00 424016 SURYAPET 400.00 2 174.54 0D

424003 GHANAPUR 400.00 414007 TALLAPALLI 400.00 1 155.26 0G

424003 GHANAPUR 400.00 414010 KURNOOL 400.00 1 226.5 0H

424003 GHANAPUR 400.00 424002 RSTPS NTPC 400.00 1 201.25 0B

424003 GHANAPUR 400.00 424002 RSTPS NTPC 400.00 2 201.25 0E

424003 GHANAPUR 400.00 424006 MAMIDIPALLI 400.00 1 46 0D

424003 GHANAPUR 400.00 424008 GAJWEL 400.00 1 72.95 -0.45351A


Page 2 of 5

424003 GHANAPUR 400.00 424011 MALKARAM 400.00 1 54.9 -0.4535A

424003 GHANAPUR 400.00 424021 MHSWRM-PG 400.00 1 56.15 0C

424004 KHAMMAM 400.00 414007 TALLAPALLI 400.00 1 144.58 0C

424004 KHAMMAM 400.00 414007 TALLAPALLI 400.00 2 144.58 0F

424004 KHAMMAM 400.00 414007 TALLAPALLI 400.00 3 144.58 0H

424004 KHAMMAM 400.00 414008 NUNNA 400.00 1 114.78 0E

424004 KHAMMAM 400.00 414011 KALPAKKA 400.00 1 364 -0.5714G

424004 KHAMMAM 400.00 424006 MAMIDIPALLI 400.00 1 198 0D

424004 KHAMMAM 400.00 424006 MAMIDIPALLI 400.00 2 198 0I

424004 KHAMMAM 400.00 424010 WARANGAL 400.00 1 117.09 -0.4535A

424004 KHAMMAM 400.00 424012 KTPS-VI 400.00 1 67.76 0B

424004 KHAMMAM 400.00 424012 KTPS-VI 400.00 2 67.76 0D

424004 KHAMMAM 400.00 424020 ASUPAKA 400.00 1 131.07 -0.5714A

424006 MAMIDIPALLI 400.00 424003 GHANAPUR 400.00 1 46 0A

424006 MAMIDIPALLI 400.00 424004 KHAMMAM 400.00 1 198 0D

424006 MAMIDIPALLI 400.00 424004 KHAMMAM 400.00 2 198 0G

424006 MAMIDIPALLI 400.00 424019 DINDI 400.00 1 74.91 0B

424006 MAMIDIPALLI 400.00 424019 DINDI 400.00 2 74.91 0E

424013 SHANKARPALLI400.00 424008 GAJWEL 400.00 1 105 0D

424013 SHANKARPALLI400.00 424016 SURYAPET 400.00 1 231 0E

424013 SHANKARPALLI400.00 424016 SURYAPET 400.00 2 231 0H

424013 SHANKARPALLI400.00 424017 NARSARPUR 400.00 1 60.92 0A

424013 SHANKARPALLI400.00 424022 MAHES-TS 400.00 1 83.99 0B

424013 SHANKARPALLI400.00 424022 MAHES-TS 400.00 2 83.99 0G

424016 SURYAPET 400.00 414013 VTS-IV 400.00 2 130.95 0B

424016 SURYAPET 400.00 414042 K V KOTA 400.00 1 174.54 0A


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424016 SURYAPET 400.00 414042 K V KOTA 400.00 2 174.54 0G

424016 SURYAPET 400.00 424011 MALKARAM 400.00 1 135.56 0E

424016 SURYAPET 400.00 424013 SHANKARPALLI400.00 1 231 0D

424016 SURYAPET 400.00 424013 SHANKARPALLI400.00 2 231 0H

424019 DINDI 400.00 424005 SRISAILAMLB 400.00 1 73.02 0A

424019 DINDI 400.00 424005 SRISAILAMLB 400.00 2 73.02 0D

424019 DINDI 400.00 424006 MAMIDIPALLI 400.00 1 74.91 0B

424019 DINDI 400.00 424006 MAMIDIPALLI 400.00 2 74.91 0G

424020 ASUPAKA 400.00 414011 KALPAKKA 400.00 1 131.07 0D

424020 ASUPAKA 400.00 424004 KHAMMAM 400.00 1 131.07 0A

424021 MHSWRM-PG 400.00 414010 KURNOOL 400.00 1 175.01 0F

424021 MHSWRM-PG 400.00 424003 GHANAPUR 400.00 1 56.15 0D

424021 MHSWRM-PG 400.00 424022 MAHES-TS 400.00 1 1.55 0B

424021 MHSWRM-PG 400.00 424022 MAHES-TS 400.00 2 1.55 0A

424022 MAHES-TS 400.00 424013 SHANKARPALLI400.00 1 83.99 0B

424022 MAHES-TS 400.00 424013 SHANKARPALLI400.00 2 83.99 0F

424022 MAHES-TS 400.00 424021 MHSWRM-PG 400.00 1 1.55 0A

424022 MAHES-TS 400.00 424021 MHSWRM-PG 400.00 2 1.55 0D


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From Bus

NumberFrom Bus Name

To Bus

NumberTo Bus Name Ckt Id Length, km

Line Reactor VARS

at FROM BUS End

(pu)

New OVR Grading (at

FROM BUS end)

337003 WARDHA-PG 765.00 427001 NIZAMABAD 765.00 1 291.2 -2.4A

337003 WARDHA-PG 765.00 427001 NIZAMABAD 765.00 2 291.2 -2.4E

427001 NIZAMABAD 765.00 337003 WARDHA-PG 765.00 1 291.2 -2.4B

427001 NIZAMABAD 765.00 337003 WARDHA-PG 765.00 2 291.2 -2.4E

427001 NIZAMABAD 765.00 427002 MHSWRM 765.00 1 240 -2.4C

427001 NIZAMABAD 765.00 427002 MHSWRM 765.00 2 240 -2.4A

427002 MHSWRM 765.00 427001 NIZAMABAD 765.00 1 240 -2.4A

427002 MHSWRM 765.00 427001 NIZAMABAD 765.00 2 240 -2.4E


2. Over Voltage Relay Gradings:

Revised OVR Gradings for certain 765 kV Transmission Lines of Southern Region


Page 5 of 5

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