SOUTHERN REGIONAL POWER COMMITTEE - SRPC, … · SOUTHERN REGIONAL POWER COMMITTEE BANGALORE ... operation of busbar protection of ... DR report of 400KV simhadri vemagiri line-2

SOUTHERN REGIONAL POWER COMMITTEE

BANGALORE

Agenda for the 40th Meeting of

Protection Coordination Sub-Committee

of SRPC to be held on 29.01.2015 (Thursday)

1. Introduction

2. Confirmation of Minutes of last PCSC meeting

Confirmation of minutes of 39th

Protection Coordination Sub-Committee meeting

held on 30.12.2014.

3. Grid Occurrences (w.r.t. SRLDC and NTPC letters)

Grid Disturbance (GD), Grid Incidences (GI), failure of Auto-reclosing (A/R), and

Over-Voltage (O/V) trippings that occurred during the last one month period (Dec, 2014 – Jan, 2015) would be discussed in the PCSC meeting. [Annexure-I]

4. Submission of reports/compliance by Constituents

4.1. Details for Grid Occurrences (to be submitted by 23.1.2015)

The Constituents are requested to send the following information in respect of

Grid Occurrences as given in Sl. no. 3 (also indicated as squared items in Annexure-II) to have fruitful discussions in the PCSC forum.

(a) First Information Report (FIR)

(b) Event Logger (EL) output

(c) Disturbance Recorder (DR) output

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

system conditions)

(e) Single line diagram of the station with switching devices,

CT, PT and relay details

(f) Relay settings adopted

(g) Remedial measures taken/suggested by the

Substation/Utility/SLDC/ SRLDC

4.2 Status of pending PCSC recommendations

Status of the pending protection recommendations (from 30th

PCSC to 37th

PCSC) as circulated vides email dt 01.12.2014 (Annexure-III) may please be

sent latest by 23.01.2015.

4.3 Remedial measures for tripping events of "TL under Forced Outage"

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

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

Agenda for the 40th Protection Coordination Sub Committee Meeting to be held on 29.01.2015 Page 2

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

Forced Outage")

4.4 Certificate for Healthiness of Batteries

Ref: Recommendations of Enquiry Committee

(NEW grid disturbance on 30th

& 31st July, 2012)

With reference to the above constituents are required to submit 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).

The certificate is being communicated to CEA/MoP.

The constituents are requested to submit the healthiness of batteries certificate

on monthly basis (i.e. on 7th

day of the month).

The following constituents are requested to send the report regularly:

TSGENCO (Hydro), KPTCL, NPCIL(MAPS)

4.5 Compliance measures for orders of Hon’ble CERC

Ref: Petition No. 146/MP/2013 with I.A. 36/2013 Order Dt. 20.02.2014

The constituents are requested to update the implementation status for Phase-I

& Phase-II activities.

The issue would be discussed in the meeting.

4.6 Completed dynamic study data

In the earlier meetings of PCSC, the forum had decided to collect the Dynamic

study data from the utilities to study the Southern Region system. The

dynamic study format was circulated to the constituents to send the Generator,

Excitation system, Governor, HVDC parameters. The forum opined that the

dynamic study details of the IPPs also are necessary to conduct the study of

SR system.

All the SLDCs were requested to direct the embedded IPPs connected at 220

KV and above voltage level to send the completed dynamic study format to

SRPC, Secretariat.

It was requested that the dynamic study data in the stipulated format may be

sent to SRPC at the earliest by email.

4.7 Configuration change details

It was agreed in the PCSC forum that if any change in the system

configuration ( i.e. addition of Generating Units, Capacitors, Reactors, LILO

etc) are to be highlighted and brought to attention of PCSC forum during the

PCSC Meetings.

This would enable utilities to review their protection settings if any change in

the adjoining utilities to have better protection coordination in the Southern

Region.

All the constituents are requested to send the change in the configuration in

their system if any to the PCSC forum on monthly basis.

http://srldc.in/DailyReport.aspx

Agenda for the 40th Protection Coordination Sub Committee Meeting to be held on 29.01.2015 Page 3

5. Other Protection Issues

5.1 Non-Submission of Tripping Reports

Non-furnishing of Tripping details including Disturbance Recorder/Sequential

Event logger output in compliance of Regulations 5.2 (r) of IEGC – as per the

provisions under clause 1.5 of IEGC 2010 would be discussed in the PCSC meeting. Annexure-V

5.2 Quantum of df/dt relief in SR

The issue would be discussed in the meeting.

5.3 Protection Logic checking of Critical Substations

Logic checking of following Critical Substations in the Southern Region had

been approved in the SRPC meeting held on 18.05.2013 at Bangalore.

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

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

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

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

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

6. Sending Agenda items for the PCSC meetings

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

meetings on a 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.

7. Review Meeting to discuss the status of Phase-I & II of DPR

The Status of implementation of Phase-I and II Protection Audit recommendation will

be discussed during the afternoon section of the meeting.

8. Date of next PCSC meeting

The 41st PCSC meeting would be conducted on 26.02.2015 (Thursday) at SRPC,

Bangalore.

*******

ANNEXURE- I

एस.आर. .स 40 –स एए Agenda Points for 40thmeeting of Protection Sub-Committee of SRPC

1. स / स र - Details of Grid Disturbances:

Sr. No.

.स . र /

Details of Event

र / Date &

स य /Time र / Reason

/Remarks

/ Category

1

Complete outage of 220kV Ambewadi station of KPTCL

22-12-2014 at 21:22 hrs

Triggering incident was B-phase to earth fault in 220kV Ambewadi-Nagjheri line-1. B-pole of breake did not open at Ambewadi end. LBB protection not available at Ambewadi end. All elements tripped on Zone-2 from remote ends.

GD-1

2. स / स र - Details of Grid incidents:

Sr. No.

.

स .

र / Details

of Event

र / Date

&

स य /Time

र / Reason /Remarks

/ Category

1

Tripping of 400kV Vijayawada-Gajuwaka line

18-12-2014 at 18:33 hrs

Line tripped due to operation of TEED protection at Gajuwaka end due to opening of jumper of Y phase CT

--

2

Tripping of HVDC Bhadrawati pole-1

22-12-2014 at 15:49 hrs

Mal-operation of the Bucholz relay in Converter Transformer had caused the tripping of Pole-1

GI-2

3

Complete outage of 110kV bus and connected elements at 220/110kV Kalamashery Station of KSEB

30-12-2014 at 10:11 hrs

All connected elements and 220/110kV ICT’s tripped.

GI-1

4

Tripping of 400 kV TALAGUPPA – HASSAN line

01-01-2015 at 13:38 hrs

Line tripped on R-phase to earth fault at hassan end on operation of distance Zone-2 due to non-receipt of carrier. From D.R of Talaguppa end it is observed that fault had occurred in Y-phase.

5

Tripping of 400kV Kayathar-Karaikudi line-2 at ICT-1,2&3 at kayathar

07-01-2015 at 23:25 hrs

B Ph CT of ICT-2 failed resulting in operation of busbar protection of Bus-2 and differential protection of ICT-2

GI-2

6

Tripping of HVDC BHADRAVATHI POLE-2

08-01-2015 at 9:57 hrs

Pole tripped with non valid tap code alarm

GI-2

ANNEXURE- I

7

Tripping of ICT-2 at Vemagiri, 400kV Vemagiri-Konaseema-1 & 400kV Vemagiri-Gautami line-1

09-01-2015 at 11:54 hrs

Tripped on Direct trip receive GI-2

3. Lines tripping due to PLCC mal-operation

Sr. No.

.

स .

र /

Details of Event

र / Date

&

स य /Time

र / Reason /Remarks

/ Category

1

Tripping of 400kV Ghanapur-Mamidapalli line

22-12-2014 at 10:52 hrs And on 24-12-2014 at 11:38hrs & 16:16hrs

Line tripped at Mamidipally end only due to direct trip received from 400kV Ghanapur Substation. Suspected PLCC maloperation had caused tripping of line

--

2

Tripping of 400kV Ramagundam-Ghanapur line-4

31-12-2014 at 15:36 hrs

Line tripped due to suspected PLCC mal-operation at Hyderabad end. Ramagundam end tripped on direct tripreceive

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

Sr. No.

Element Date & Time

Reason

1 220kV Sedam-Tandur line 20-12-2014 at

22:20 hrs Line tripped on Y-phase to earth fault from both the ends

2

400 kV HYDERABAD - KURNOOL 07-01-2015 at 6:17 hrs

Line tripped on R-phase to earth fault. a/R lock out observed in E.L of Hyderabad end

3 220kV Neyveli-Bahoor line 11-01-2015 at

15:42 hrs R-phase to earth fault. Line did not auto reclose

5. NTPC Letter

Sub: DR report of 400KV simhadri vemagiri line-2 Auto reclosure -reg

Dear sir

Please find attached the List of DR reports triggered on 29.12.2014 at 13:19:06

hrs and 13:24:51 hrs due to Auto reclosing of Simihadri/vemagiri Line-2

respectively. Due to this disturbance critical drives of Simhadri station got

affected & voltages gone down to 62.3KV from 230KV (P-N)& fault current gone

upto to 16.1KA from 400A. This is for your information and necessary action at

your end for avoiding the disturbances to happen in future.

With Regards

C MALAKONDAIAH AGM I/C

ELECTRICAL MAINTENANCE DEPT, NTPC SIMHADRI

ANNEXURE- I

6. 230/110 kV Villianur Auto Sub-station Interruption.

ANNEXURE -II

ANNEXURE -II

Meeting No /

Index

Meeting

Sl.NO

Details of

Event

Date Reason PCSC Recommendations Utility Responsible

to implement*

Status of Recommendation Remarks

36/I/9 6 220kV

Srisailam

right bank

station

03-09-2014 It was reported

that trip wire to

circuit breaker of

220kV Dindi-2

was open which

resulted in

operation of LBB

protection and

tripping of all

elements

connected to

220kV Bus-2.

Deliberation &

Recommendation:

a. The issue was discussed

in the Protection System

Analysis Group (PSAG-9)

meeting held at Srisailam

Right Bank Power House

(SRBPH) on 14 &

15.10.2014

b. APGENCO was

requested to inform the steps

/action taken to implement

the PSAG-9 meeting

recommendations during

the next PCSC.

APGENCO Pointwise compliance on PSAG-

9 MOM is furnished to SRPC

partially

completed and

partly

Pending

36/I/10 7 220kV

Srisailam

right bank

station

03-09-2014 Mal-operation of

LBB relay which

resulted in tripping

of all elements

connected to

220kV Bus-1

Deliberation &

Recommendation:

a. The issue was discussed

in the Protection System

Analysis Group (PSAG-9)

held at Srisailam Right Bank

Power House (SRBPH) on

14& 15.10.2014 .

b. APGENCO was

requested to inform the steps

APGENCO Pointwise compliance on PSAG-

9 MOM is furnished to SRPC

partially

completed and

partly

Pending

ANNEXURE - III

35/II/1 4 400 kV

KURNOOL

-

SRISAILAM

29-07-2014 Y-phase to earth

fault. Line did not

auto reclose.

• Old static relay would be

replaced by numerical

relay.

• APTRANSCO informed

the forum that the static

relay would be replaced

with the Numerical realy

with in 3 month’s time.

APTRANCO APTRANSCO informed that

one number of Numerical

distance relay was allotted to

replace the static relay on

Srisailam feeder at Kurnool

Substation as an inteirm

measure.

Rely yet to be commissioned.

Pending

Meeting No /

Index

Meeting S.NO Details of

Event

Date Reason PCSC Recommendations Utility Responsible to

implement*


30/I/A 1 RTPS

Tripping

incidents and

the Spl

meeting held

at RTPS on

13th and 14th

March 2014

Mar-14 Spl meeting held

at RTPS on 13th

and 14th

March

2014

The PCSC forum recommended for

replacement of existing

electromechanical relays with

Numerical relays.

KPCL (1) e- Tender folated for the retrofit of

existing static relays with Numerical

version for lines M.nagar,M.bad,ICT-

1 & 2 -Technical Bid opened & price

bid yet to be opened.

(2) Retrofit of existing bus bar (CAG-

34) with numerical version -

Budgetetory offers obtained and is

under process.

Pending

33/II/3 9 400kV

Hiriyur-BTPS

line-2

22-05-14 &

23/05/2014

B phase to

ground fault had

occurred in line

and line auto

reclosed at

Hiriyur end but

failed to reclose

at BTPS end.

• KPCL: A/R is not yet enabled at

Raichur plant.

Recommendation:

The PCSC forum requested KPCL to

enable the A/R feature at RTPS end

before next PCSC meeting (i.e. 31st

July, 2014.

KPCL A/R at BTPS end will be enabled

during November 2014 end and needs

LC.

Pending

34/III/1 8 400kV

Raichur-BTPS

line

26-06-2014 Transient fault in

R-phase.

Line did not auto

reclose

Recommendation:

A/R at BTPS end to be made

operational within one month

KPCL A/R at BTPS end will be danbled

during November, 2014End and

needs LC

Pending

ANNEXURE - III

Meeting No /

Index


Event


implement*


ANNEXURE - III

35/I/2 1 220 kV

KAIGA –

KODASALL

Y an 220kV

Kodasalli -

Nagjheri line

19-07-2014 220kV Kaiga-

Kodasalli line

tripped on

operation of over

current

protection.

It was also

reported that 220

kV Kodasalli-

Nagjheri line had

tripped due to

fault.

From D.R of

KAIGA station it

was observed

that the fault

persisted for

around 340 ms.

Recommendations:

a) KPCL was requested to send the

detailed tripping analysis report to

SRLDC and SRPC.

b) The utilities are requested to send

the single Line Diagram / Lay out

plan of the affected Substation/

System.

c) KPTCL /KPCL to review the SOTF

settings for Kodasalli – Nagjheri lines.

d) Resistive reach of the distance

relay shall be reviewed to take care of

the high resistance fault.

KPCL (i) As per the proceeds of the PSAG-

10 relays will be replaced.

Temporarily aranged.

(ii) SOTF setting already reviewed.

(iii) Resistive reach is calculated and

will be uploaded in the seond week of

Dec.2014.

Pending

34/I/6 2 400/220 kV

ICT-1 & 2 at

MUNIRABA

D

16-07-2014 As reported

directional over

current relay of

ICT’s operated

due to snapping

of line jumper

in 220kV

Lingapur line.

Recommendations:

Bus bar protection shall be

provided by asset owner ( i.e KPTCL)

.

Settings for main distance

protection & Overcurrent protection

shall be examined and reviewed.

Time synchronization of the

Substation shall be ensured.

SRLDC for trip analysis.

KPTCL Management approval is obtained for

taking up the work of providing bus

bar protection to 220kV buses at

Guddadahally (Munirabad) Sub

Station along with replacement of 3

core/age old CTs of 220kV bays

belong to KPTCL.

Finalization of scheme/specification is

under process.

Pending

Meeting No /

Index


Event


implement*


ANNEXURE - III

36/I/5 2 ICT -1 & 2 at

Guttur

Substation

26-08-2014 ICT’s tripped

on operation of

Earth fault

relay.

Triggering

incident was

failure of

Jumper in

220kV Guttur-

Neelagunda line.

Recommendations:

a. Protection System Analysis Group

(PSAG-8) was held on 25 &

26.09.2014 at Guttur (400 KV,

KPTCL SS ) to discuss the frequent

tripping of 400KV Kaiga-Guttur lines

on account of over-voltage and

transient faults.

The Minutes of the PSAG-8 Meeting is

enclosed herewith as Annexure – V.

b. KPTCL was requested to send the

steps/action taken to implement the

recommendations of the PSAG-8

meeting held at Guttur on

25&26.09.2014 to the PCSC.

KPTCL Pointwise compliance on PSAG-8

MOM is furnished to SRPC

partially

completed and

partly Pending.

36/I/8 5 Multiple

Tripping at

400 kV

Guttur station

12-09-2014 400kV Kaiga-I,

Hiryur-I,

Narendra-I &

ICT-I tripped at

Guttur station

due to operation

of bus bar

protection of

400kV Bus-1 at

Guttur.

It was reported

that the LBB

protection acted

due to wrong

configuration of

distance relay.

Recommendations:

a. Protection System Analysis Group

(PSAG-8) was held on 25&

26.09.2014 at Guttur (400 KV,

KPTCL SS ) to discuss the frequent

tripping of 400KV Kaiga-Guttur lines

on account of over-voltage and

transient faults.

The Minutes of the PSAG-8 Meeting is

enclosed herewith as Annexure – V.

b. KPTCL was requested to

steps/action taken to implement the

recommendations of the PSAG-8

meeting held at Guttur on

25&26.09.2014 to the PCSC.

KPTCL Pointwise compliance on PSAG-8

MOM is furnished to SRPC

partially

completed and

partly Pending

Meeting No /

Index


Event


implement*


ANNEXURE - III

37/I/5 5 220kV

Ambewadi-

Ponda line

25-09-2014 As per FIR line

was hand tripped

due to

220/110kV Bus

dead.

Reason for bus

de-energization

may be

furnished to

PSC.

Recommendations:

a. A trip analysis report shall be with

the corrective actions for the following

issues shall be sent to PCSC forum.

b. Measures for preventing

Ambewadi – Nagjheri line -1 opening

in case of fault on the Ambewadi –

Nagjheri line -2 and vice versa.

KPTCL Yet to be informed Pending

Meeting No / Index Meeting S.NO Details of

Event


implement*

Status of

Recommendation

Remarks

34/I/3 1 Tripping of

HVDC

Bhadravati

Pole-1 & 2

09-07-2014 As reported pole-1&2 tripped

due to auxiliary supply

failure.

Recommendations:

SRTS-I take up the issue with WRTS to submit

the report as per IEGC guidelines.

requested to send a letter to

WRLDC to submit the reports to SR also.

SRPC would take it up with WR and PGCIL if

the issue is not getting resolved.

Complete analysis of the faults and

rectification/remedial action taken to avert

similar occurrence in the HVDC Back to Back

station shall be submitted.

PGCIL Yet to be informed Pending

34/I/7 3 HVDC

BHADRAVA

THI POLE 2

18-07-2014 As reported pole-2 tripped

due on 5th harmonic alarm.

Recommendation :

Complete analysis of the faults and

rectification/remedial action taken to avert

similar occurrence in the HVDC Back to Back

station shall be submitted.

The PCSC forum recommended PGCIL, SRTS-I

take up the issue with WRTS to submit the

report as per IEGC guidelines.

SRLDC is also requested to send a letter to

WRLDC to submit the reports to SR also.

Based on the SRTS/SRLDC correspondences,

SRPC would take it up with WR and PGCIL if

the issue is not getting resolved.


ANNEXURE - III


Event


implement*

Status of

Recommendation

Remarks

ANNEXURE - III

36/II/5 11 400kV

Ramagundam-

Chandrapur

line – 1

25-08-2014 Line tripped on B-phase to

earth fault.

As per FIR of chandrapur

station, line did not auto

reclose as auto reclose is kept

out of service.

Recommendation:

PGCIL to take up the issue with OEM in this

regard.


Meeting

No /

Index

Meeting

S.NO

Details of Event Date Reason PCSC

Recommendations

Utility Responsible

to implement*

Status of

Recommendation

Remarks

30/II/8 4 Tripping of

NCTPS-Alamathy-

1 & NCTPS-

S.V.Chatram-1

26-02-2014 TANTRANSCO

informed that tripping

occurred when the

Almatti CB was charged

at NCTPS end after the

maintenance.

SRLDC enquired about

the commissioning of

DR and EL at NCTPS.

TANTRANSCO

informed that only

standalone DR and EL

are not yet installed, but

relays have built in

DR/EL features.

TANTRANSCO

informed that issue was

taken up with the OEM.

TANTRANSCO TANTRASNCO informed

that DR and EL yet to be

commissioned

Pending

36/II/9 14 400kV Arasur-

Mettur Line I

29-09-2014 Recommendation:

Mettur S/s to Enable

A/R Scheme.

TANTRANSCO During the 38th PCSC

meeting, TANTRANSCO

informed that the Auto

Reclosing facility would

be enabled within 15 days.

Pending

ANNEXURE - III

Meeting

No /

Index

Meeting

S.NO


Recommendations

Utility Responsible

to implement*

Status of

Recommendation

Remarks

ANNEXURE - III

37/II/3 13 400kV Mettur-

Arasur line-1

29-09-2014 Line tripped

due to Y-

Phase to earth

fault.

Line did not

auto reclose as

Auto reclose

scheme is kept

in non-auto

mode.

A/R is not in

service.

TANTRANSCO Yet to be informed Pending

Meeting

No / Index

Meeting S.NO Details of Event Date Reason PCSC Recommendations Utility Responsible

to implement*

Status of

Recommen

dation

Remarks

30/II/1 2 Tripping of 400kV

Srisailam-

Satenapalli line-1&2

17-02-2014 Tripped due to

PLCC mal-

operation.

Status of D.R/ EL

at Satenapalli

TSGENCO informed that the

line tripped at Satenapalli end

due to receipt of continuous

direct trip signal from

Srisailam.

TSGENCO also informed that

the issue has been rectified on

subsequent day and no issues

were observed.

The new relay would be in

place within 1 1/2 months.

TSGENCO Yet to be

informed

Pending

33/II/5 10 400kV VTPS –

Malkaram-1

26-05-2014 400kV VTPS-

Malkaram line-1

tripped on a y-

Phase to ground

fault.

Line auto-reclosed

at Malkaram end.

Recommendation

PCSC forum requested SLDC

of Andhra Pradesh /

Telangana to take up the issue

with the generator ( VTPS) for

attending/ correcting the

problem.

TSGENCO Yet to be

informed

Pending

34/I/5 6 400kV Srisailam-

Mamidapalli line-2

10-07-2014 D.R/ E.L of Srisailam station

were not furnished.

Deliberation:

Discussed in S.No. 4

TSGENCO Yet to be

informed

Pending.

ANNEXURE - III

Meeting

No / Index

Meeting S.NO Details of Event Date Reason PCSC Recommendations Utility Responsible

to implement*

Status of

Recommen

dation

Remarks

ANNEXURE - III

37/III/2 15 400kV Srisailam-

Satenapalli-2

19-09-2014 D.R of Srisailam end not

submitted

TSGENCO Yet to be

informed

Pending.

Meeting

No / Index

Meeting

S.NO


Recommendations

Utility Responsible

to implement*

Status of

Recommendation

Remarks

37/II/5 14 400 kV

NEYVELI TS 2

(EXP) -

PUGALUR

05-10-2014 Y-phase to earth fault

had occurred in line.

Line did not auto

reclose.

DT was received from

Neyveli TS2(EXP)

end

Have to submit

remedial measures.

NLC Yet to be informed Pending


400/220kV ICT-

1&2 at UPCL

04-10-2014 ICT-1&2 tripped

during transient fault

in R-phase in 400kV

Hassan-UPCL line-1

Recommendations:

To avoid tripping of

ICTs for line fault,

UPCL is requested to

review the settings of

ICT’s SEF relay and

consider IDMT

setting instead of

existing Definite Time

setting.

UPCL Yet to be informed Pending

ANNEXURE - III


Event


implement*


36/II/3 10 400kV

JSW-Guttur

line

21-08-2014 R-phase to earth

fault.

Line did not auto

reclose.

• Decapping of insulator resulted in persisting fault that led to

the tripping of the line.

JSW /

KPTCL

Yet to be informed Pending


400kV NPS-

MEPL line

08-10-2014 Line tripped due to

DT receive from

MEPL

Recommendations:

a. The exact reason for receipt of DT signal at NPS end from

MEPL end has to be found out and corrective measures need to

be taken up by both MEPL and NPS to avoid its recurrence.

b. The forum decided to invite MEPL and SEPL whenever there

is a tripping involving their power stations.

MEPL /

PGCIL


(MEPL)

33/II/2 8 400kV

Ramagundam-

Hyderabad

line-4

19-05-2014 Transient fault had

occurred in R-phase.

Line auto reclosed at

Ramagundam and

failed to reclose at

Hyderabad due to

direct trip receive.

• NTPC: no PLCC counter has gone up (incremented) at

Ramagundam

• PGCIL: DT was received from Ramagundam, and hence the

tripping of the line.

Recommendation

joint checking of PLCC

system by NTPC and SRTS I, PGCIL .

The report to be sent to PCSC forum at the earliest.

NTPC,

PGCIL

Yet to be informed. Pending.

33/II/10 12 400 kV

RAMAGUN

DAM -

WARANGA

L

13-06-14 B-phase to ground

fault had occurred.

Line failed to

reclose from

Ramagundam end.

NTPC:

Main-I distance protection relay sensed single phase fault and

Main-II relay (RAZFE-ABB) sensed R-Y (line to line) fault

which got priority over single phase fault and the line was given

3-phase tripping.

NTPC,

PGCIL,

APTRANSCO


ANNEXURE - III


Event


implement*


ANNEXURE - III

32/II/6 6 400kV

Ramagundam-

Chandrapur

line – 1

28-04-2014 R-phase to earth

fault had occurred in

line. Line did not

auto reclose

NTPC:

•Auto reclose feature is not in service on Ramagundam –

Chandrapur line due HVDC back-to-back link at Chandrapur. It

was informed that HVDC link faces problem if there is auto-

reclose feature.

•It was informed that nowhere in the country, 3-phase auto

reclose is implemented for the lines at generating station.

•NTPC informed that sending DT for the earth fault at

Chandrapur end is not a correct operation.

PGCIL:

•Problematic protection coupler is to be replaced for the line.

•3-phase auto reclose feature is implemented on the Gazuwaka-

Jeypore which is having HVDC back-to-back at Gazuwaka.

Synchro check is done and 1-phase auto reclose is converted into

3-phase auto reclose.

SRLDC:

•3-phase auto reclose feature implemented on Gazuwaka-Jeypore

line is not known to SRLDC and it is not clear under what

conditions it was approved. However, SRLDC recommends 1-

phase auto reclose.

MS i/c:

•PGCIL should come back with a plan for implementing auto

reclose feature on Ramagundam – Chandrapur line.

PGCIL /

NTPC

Yet to be informed. Pending


400kV

Nellore

pooling station-

MEPL line

23-05-2014 Line tripped at

Nellore pooling end

only due to direct

trip receive from

MEPL end.

FIR:

At NPS end, line tripped after receiving DT.

At MEPL end, there was DC earth fault.

Deliberations:

The issue was noted.

PGCIL /MEPL Yet to be informed. Pending

(MEPL)

36/II/2 9 400kV

Madurai-

Costal

Energy

21-08-2014 B-phase to earth

fault.

Line did not auto

reclose at Coastal

Energy end.

SRLDC:

There was an earth fault on B-phase and subsequently A/R

scheme has been rectified.

TANTRANSCO /

PGCIL /

Coastal Energy

Yet to be informed Pending(Coas

tal Energy),

(TANTRANS

CO)


Event


implement*


ANNEXURE - III


400KV

Hassan-

UPCL line-2

25-09-2014 High resistance fault

as the fault ampere

was very less i.e.,

0.6kA at Hassan end

and nearly 0.9kA at

UPCL end.

Back up earth fault

protection had

operated at Hassan.

At UPCL end the

high resistance fault

got converted into a

R ph-B-ph fault

which resulted in

operation of

distance protection

Zone-1.

The reason for non-

picking up of Back

up earth fault at

UPCL needs

investigation.

Recommendations:

a. At UPCL end, unused zones of distance protection (probably

zone 5 to 8) shall be disabled.

b. At UPCL end, time synchronization between main-1 and

main-2 relays shall be ensured.

c. UPCL shall ensure time synchronization with Hassan

substation.

d. Reasons for non operation of back up protection at UPCL

for high resistance fault is to be submitted.

e. Reasons for not sending DT to UPCL by Hassan end is to be

submitted.

f. Settings of UPCL are to be reviewed and informed to PCSC

forum.

UPCL /

KPTCL /

Yet to be informed Pending(UPC

L).


Event


implement*


ANNEXURE - III

31/I/5 2 400 kV

HASSAN -

UPCL 2

28-Mar-14 From D.R of UPCL

end it is observed

that earth fault

protection of line

got operated which

resulted in tripping

of line.

·It was noted that Hassan – UPCL lines tripped on account of

back up earth fault protection.

UPCL said that more line trippings (usually between 12.00 and

3.00 PM) are due to bamboo/ rubber trees on the right of way.

UPCL said that relays would be tested by M/s Alstom shortly.

Effective patrolling of the line would be carried out as decided

in the meeting held by concerned utility officials.

PGCIL suggested that as many trips are attributed to high

resistance fault, carrier aided directional scheme is required.

UPCL to adopt IDMT characteristics for back up earth fault

protection.

UPCL/

KPTCL /

PGCIL

Yet to be informed. Pending

ANNEXURE- IV

Remedial Measure for the Critical Tripping Incidents

SN Element Name Outage

date/time

Revival

date/time

Reason for Outage Remedial Measure

1 400 Kv HASSAN - UPCL 2 17-07-2014/

16:58:00

17-07-2014/

17:38:00

TRIPPED ON R-N FAULT

2 400 Kv MADURAI - COSTAL

ENERGY

21-08-2014/

14:30:00

21-08-2014/

15:03:00

TRIPPED WHILE

CHECCKING A/R CKT

3 400 Kv MADURAI - NTPL 04-10-2014/

13:41:00

04-10-2014/

14:12:00

R-N FAULT

4 400/220 kV ICT-1 AT TRICHUR 09-11-2014/

19:21:00

09-11-2014/

20:56:00

TRIPPED

5 220 kV YERANDAHALLY - HOSUR 10-11-2014/

11:06:00

10-11-2014/

11:52:00

TRIPPED ON D.E.F.R

INDICATION

6 400 Kv ALM - SVCTM-I 17-11-2014/

16:17:00

17-11-2014/

18:08:00

TRIPPED AT ALM END.

7 400/230 Kv ICT 3AT ALAMATHY 28-11-2014/

14:04:00

28-11-2014/

18:23:00

DC LEAK

8 400/220 kV ICT-1 AT

NEELAMANGALA

30-11-2014/

15:25:00

30-11-2014/

15:52:00

TO ATTEND HOTSPOT &

COMBINATION CHANE

9 220 Kv CHIKKODI - MUDUSHINGI 01-12-2014/

16:17:00

TRIPPED DUE TO FAULT

AT 48KM FROM CHIKKODI

10 220 Kv CHIKKODI - TALANDGE 01-12-2014/

16:17:00

02-12-2014/

03:12:00

TRIPPED DUE TO FAULT

AT 48KM FROM CHIKKODI

11 400/110 kV ICT 1AT ALAMATHY 09-12-2014/

13:24:00

09-12-2014/

17:14:00

TRIPPED DUE FALSE

WINDING TEMP HIGH

ALARM (IDLE CHARGED)

12 HVDC BHADRAVATHI POLE 1 11-12-2014/

08:05:00

11-12-2014/

17:57:00

TRIPPED DUE TO VBE

GATE UNIT FAULTY @

SOUTHSIDE

13 400 Kv KURNOOL - THIRUVALLAM

2

12-12-2014/

01:58:00

12-12-2014/

YB FAULT

14 400 kV NELAMANGALA - HOODY 1 13-12-2014/

09:45:00

13-12-2014/

10:50:00

BUS BAR PROTECTION

OPERATED

15 400 kV NELAMANGALA - HOODY 2 13-12-2014/ 13-12-2014/ BUS BAR PROTECTION

ANNEXURE- IV

09:45:00 10:51:00 OPERATED

16 400/220 kV ICT-2 AT HOODY 13-12-2014/

09:43:00

13-12-2014/

10:54:00

BUS PROTECTION

OPERATED

17 400 Kv NELLORE - TVLLM-1 14-12-2014/

10:55:00

14-12-2014/

11:28:00

SUSPECTED PLCC MAL

OPERATION


1

15-12-2014/

09:15:00

15-12-2014/

10:02:00

REASON AWAITED

19 400 kV VIJAYAWADA - GAZUWAKA

1

18-12-2014/

18:33:00

18-12-2014/

21:09:00

JUMPER CUT AT

GAJUWAKA END

20 400 kV PUGALUR -

KALAIVANTHAPATTU 2

18-12-2014/

18:44:00

DT RECEIVED AT

PUGALUR END

21 220 kV HOSUR - SOOLAGIRI 1 19-12-2014/

17:26:00

RY FAULT

22 400/230 kV ICT-2 AT PUGALUR 20-12-2014/

16:51:00

20-12-2014/

19:29:00

BUCHOLZ RELAY

OPERATED

23 400 kV GHANAPUR - MAMIDIPALLY 22-12-2014/

10:52:00

22-12-2014/

11:11:00

PLCC MALOPERATION

TRIPPED AT MDPLI END


15:49:00

22-12-2014/

16:17:00

BUCHHOLZ RELAY

OPERATION IN POLE 1

WEST Y PHASE


11:38:00

24-12-2014/

11:54:00

DT RECEIVED AT MMDPLY


16:16:00

24-12-2014/

16:24:00

MAL OPERATION DT

RECIEVED AT MDPLY

27 400 kV RAMAGUNDAM -

HYDERABAD 4

31-12-2014/

15:36:00

31-12-2014/

16:16:00

PLCC MALOPERATION

28 400 kV TALAGUPPA - HASSAN 01-01-2015/

13:38:00

01-01-2015/

14:38:00

TRIPPED ON R-N FAULT

29 400 kV KAIGA - GUTTUR 2 02-01-2015/

05:14:00

TRIPPED ON B-N FAULT


2

02-01-2015/

17:28:00

02-01-2015/

22:19:00

TRIPPED DUE TO L/R DIFF.

PROTECTION OPERATED

31 220 kV AMBEWADI - PONDA 1 06-01-2015/

12:01:00

06-01-2015/

12:20:00

TRIPPED ON EARTH

FAULT

32 400/110 Kv ICT 1 AT KAYATHAR 07-01-2015/

23:35:00

08-01-2015/

02:52:00

ICT-2 B-PH CT FLASH

OVER AT KAYATHAR.


23:35:00

ICT-2 B-PH CT FLASH

OVER AT KAYATHAR.

ANNEXURE- IV

34 400 kV KAIGA - GUTTUR 1 07-01-2015/

14:35:00

B - N FAULT

35 400 Kv KAYATHAR - KARAIKUDI 1 07-01-2015/

23:35:00

08-01-2015/

02:44:00

ICT-2 B-PH CT FLASH

OVER AT KAYATHAR.


23:35:00

ICT-2 B-PH CT FLASH

OVER AT KAYATHAR.


09:57:00

08-01-2015/

10:16:00

NON VALID TAP CODE

38 400 Kv KUDAMKULAM - MADURAI 08-01-2015/

10:20:00

H/T@KKNP DUE TO

SMOKE FOUND FROM B-

PH VT CUBICLE

39 220 Kv UPPERSILURERU -

BALIMELA

08-01-2015/

16:40:00

B - N FAULT

40 400 kV KAIGA - GUTTUR 1 09-01-2015/

10:47:00

09-01-2015/

13:48:00

R - N FAULT

41 400 kV VEMAGIRI - GOUTHAMI

CCCP 1

09-01-2015/

11:54:00

09-01-2015/

13:24:00

DT RECEIVED

42 400 kV VIJAYAWADA - VEMAGIRI 1 09-01-2015/

11:17:00

09-01-2015/

11:38:00

Y - N FAULT

43 400 kV VEMAGIRI - KONASEEMA 1 09-01-2015/

11:44:00

DT RECEIVED

44 220 kV NEYVLI - BAHOOR 11-01-2015/

15:42:00

11-01-2015/

17:26:00

R-N FAULT

45 400 Kv NELLORE - THIRUVALLAM 2 13-01-2015/

12:01:00

13-01-2015/

12:37:00

TRIPPED DUE TO R-N

FAULT

ANNEXURE I

एस.आर.पी.सी40वेंप्रोटेक्शनउप–समितिकीबैठककेमऱएएजेंडे Additional Agenda Points for 40thmeeting of Protection Sub-Committee of

SRPC

1. ग्रिडडडस्टबबन्स / ग्रिडइन्सडन्टकावववरण - Details of Grid incidents:

Sr. No.

क्र.

सं.

घटनाकावववरण / Details

of Event

िारीख/ Date

&

सिय /Time

कारण / Reason टटप्पणी /Remarks

शे्रणी/ Category

1

Tripping of Unit-1 at Kudankulam

14-01-2014 at 19:20 hrs

Y-phase Differential protection of Generating transformer of Unit-1 got operated which resulted in tripping of Unit-1

--

2

Tripping of 400kV Cudappah-Chitoor line

14-01-2014 at 10:03hrs

Line tripped at Cudappah end only

3

Tripping of 220kV Sabarigiri-Theni line

15-01-2015 at hrs

LBB protection got operated at Sabarigiri end.

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

Sr. No.

Element Date & Time

Reason

1

400kV Raichur-Munirabad line 18-01-2015 at 1:39 hrs

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

ANNEXURE II

Page 1 of 2

1. Agenda Items from the Record Notes of the Special Meeting regarding

the issues pertaining to Karnataka System and BMRCL- 16-01-2015

ANNEXURE II

Page 2 of 2

2. PGCIL SR-1 Agenda Items

Sub: Over Voltage grading of newly commissioned lines in SR

This is in reference to the minutes of the 39th PCSC meeting forwarded. As

recorded in the minutes, the Grading of Over Voltage settings need to be revised and

recommended after the addition of newly added elements in Southern Region.

Presently the settings recommended by PGCIL (SR-1) CC Engg group forwarded at

the time of commissioning is implemented and put into service.

Subsequent to the receipt of the settings recommended by SRLDC / SRPC /

PCC groups, the same shall be adopted on all the feeders.

ANNEXURE III

ANNEXURE III

1

ANNEXURE III

2

ANNEXURE III

3

ANNEXURE III

4

Suggestions for providing settings for High set of Earth fault relay on HV side of Generator Transformer (with Star connection on HV side and Delta connection on LV side): Jayarajan.C.N, Executive Engineer, Protection and Monitoring Division, Kerala State Electricity Board, Kerala, India It may be noted that the high set unit of Earth fault relay on HV side of Generator Transformer may un necessarily operate for external fault even though the primary relay corresponding to that fault had operated if the relay relay has not been set properly. For explaining this let us take a bus fault for analysis. A simple diagram is given below. Hope this will suffice for calculations.

See the figure above. Here S represents the Fault MVA source, T is the Generator Transformer and G is the Generator. And let us take a line to ground fault occurs on one phase of 220KV bus. Now, we can assume the following values: Fault MVA source S: Here, 5000MVA has been taken as maximum fault level for calculation. MVA = 5000, Positive Sequence impedance (p.u) Xs1 = 1 Negative Sequence impedance(p.u) Xs2 =1 Zero sequence impedance (p.u) Xs0= 1 Per Unit values are based on 5000 MVA. Resistance values are neglected. Generator Transformer T: MVA = 100 220KV (Star)/ 11KV(Delta)

ANNEXURE-IV

1

p.u reactance = 0.15 Solidly earthed. Generator G: MVA = 100 Positive Sequence Impedance(p.u.) Xg1 = 0.15 Negative Sequence Impedance(p.u) Xg2 = 0.15 Zero sequence Impedance (p.u) Xg0 = 0.05 Resistance earthed with resistance value = R. It may be noted that zero sequence impedance and resistance R will not come into calculations as the same will become clear from following diagrams. Base MVA can be taken as 100MVA, with this p.u. impedances of Fault MVA source can be rewritten as: Positive Sequence impedance (p.u) Xs1 = 1*100/5000 = 0.02 Negative Sequence impedance(p.u) Xs2 =1*100/5000 = 0.02 Zero sequence impedance (p.u) Xs0= 1*100/5000 = 0.02 Positive Sequence Network:

POSTIVE SEQUENCE NETWORK

The above diagram can be simplified using Thevenin's theorem: Equivalent resistance = 0.02*(0.14+0.15)/(0.02+0.14+0.15) = 0.0187 The positive sequence network becomes:

F1

N1

1 p.u. 0.15

0.14 0.02

1 p.u.

ANNEXURE-IV

2

Similarly negative sequence networks becomes:

ZERO SEQUENCE NETWORK

0.02 Fo

No

0.14

0.05

3R

0.0187 F2

N2

0.0187 F1 N1

1 p.u

ANNEXURE-IV

3

For zero sequence network, equivalent resistance = 0.02*0.14/(0.02+0.14) = 0.0175 Zero sequence network becomes:

The total circuit is shown as below:

I1 = I2 = I0 = 1/ (0.0187+0.0187+0.0175) = 18.215 Out of this sequence currents, one portion flows through the GT neutral as shown below:

0.0187 F1

1p.u.

N1

F2

N2

F0 No

0.0187

0.0175

No

0.0175

.

ANNEXURE-IV

4

The per phase sequence current flowing through GT neutral = 18.215 * 0.02/(0.02+0.14) = 2.277 p.u. Total zero sequence current flowing through the transformer = 3*2.277 = 6.831p.u .................(1) Now we can imagine that the generator is out of service but GT is in service as shown in the figure below:

Positive, negative and zero sequence networks are shown below:

POSTIVE SEQUENCE NETWORK

S S

220 kV T

G

R

18.215 p.u.

0.02 0.14

No

Fo

ANNEXURE-IV

5

NEGATIVE SEQUENCE NETWORK


0.02 F2

N2

0.14

0.15

0.02 F1

N

1 p.u

0.14

1 p.u

0.15

ANNEXURE-IV

6

And its simplified forms are as given below:

POSITIVE SEQUENCE NETWOK


0.02

1 p.u

0.02 Fo

No

0.14

0.05

3R

ANNEXURE-IV

7


TOTAL CIRCUIT

0.0175 F0

N0

0.02 F2

N2

ANNEXURE-IV

8

Per phase sequence current = 1 / (0.02+0.02+0.0175) = 17.39 p.u. The total zero sequence current through GT neutral = 3*17.39*0.02/(0.02+0.14) = 6.52 p.u. ....(2) It may be noted that the current flowing through GT neutral is almost same even though the generator is in service or not. Now let us see what happens when there is no source and 220KV bus is charged from generator (dead bus charging):

S S

T

G

R F

0.02

1p.u.

0.02

0.0175

ANNEXURE-IV

9

Its positive, negative and zero sequence networks are as shown below: POSITIVE SEQUENCE NETWORK


ZERO SEQUENCE NETWORKS

0.05 0.14

No

Fo

3R

N2

0.14 0.15 F2

N1

0.14 0.15 F1

1 p.u.

ANNEXURE-IV

10

which can be simplified and connected to get total network as shown below:

Therefore, per phase sequence current = 1/(0.29+0.29+0.14) = 1.39 p.u . Total zero sequence current through GT neutral = 3*1.39 = 4.16 p.u .................................(3) Conclusion:

1. While comparing the total fault current contributions through Generator Transformer neutral vide equations (1), (2) and (3), it can be seen that the condition (1), i.e., the situation where system, GT and generator are in service, give maximum current. Maximum fault current through GT neutral = 6.831 p.u It may be noted that it is very difficult to get exact sequence network picture. Besides, it offset due to X/R due to actual system conditions to be considered while providing setting. Therefore, minimum setting shall be = 1.3*6.831 p.u = 8.88 p.u. = 9 p.u

Please note that the above value may sometimes be changed to higher value for stability if instantaneous delay is provided for the highest relay operation, if necessary.

However this value can be selected which may suffice for most of applications with 5 cycles delay.

0.29 F1

1p.u.

N1

F2

N2

F0 No

0.29

0.14

ANNEXURE-IV

11

2. In the absence of exact system configuration for analysis, settings have to be provided carefully. For avoiding maloperations due to DC offset in CTs, X/R in systems etc. 100 ms (5 cycles) may be given as delay. This delay is acceptable for the following reasons: a. The protection area of high set unit of earth fault relay is between CTs on HV side of GT

and (including) transformer HV winding. b. This area is normally covered by Restricted Earth Fault protection and Transformer

differential protection which are more sensitive than high set unit earth fault relay. c. For the above reasons in (a) and (b), the function of high set unit of earth fault relay in

HV side of Generator transformer is to act as ‘back up’ of HV side REF and transformer differential relay for faults on HV side of transformer.

3. Please note that this high set protection is effective only when the earth fault relay is located in the residual connection of HV side phase CTs and not on the neutral CT of the transformer.

ANNEXURE-IV

12

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