SOUTHERN REGIONAL POWER COMMITTEE - Kar · • The Grid Disturbance Report as submitted byAPTRANSCO...

SOUTHERN REGIONAL POWER COMMITTEE BANGALORE

Minutes of the 25th Meeting of

Protection Coordination Sub-Committee of SRPC held on 22.10.2013

1. Introduction

1.1 The 25th Meeting of Protection Coordination Sub-Committee (PCSC) was

held on 22nd October 2013 in the Conference Hall of Southern Regional

Power Committee, Bangalore. The list of participants for the PCSC meeting

is enclosed as Annexure-I.

1.2 Shri S. R. Bhat, Member Secretary i/c, SRPC welcomed the Members and

Participants to the 25th Meeting of the Protection Coordination Sub-

Committee.

1.3 MS i/c, SRPC informed the forum that the issue regarding high voltage

trippings had been discussed in the recent meeting of OCC and PCSC and

few recommendations had been suggested for implementation. Though the

constituents were requested to revert back in case of specific issues, no

feedback had been received from any of the constituents. He also informed

the forum that swapping of voltage settings on 400 KV Kaiga- Guttur lines

had been carried out as suggested in the last PCSC meeting.

1.4 MS i/c stated that there needed to be a proper mechanism to follow up on

the recommendations made in earlier Meetings. The endeavor should be to

have logical conclusion for every critical tripping incident. This would

happen only when the identified measures are implemented in a time bound

manner.

1.5 MS i/c informed that Unit 1 of Kudankulam Nuclear Power Plant had now

been synchronized and hence the proposed SPS needed to be finalized.

SRLDC had already furnished the study results to NPCIL but the response

was awaited .He also stated that the fortnightly reports on implementation of

measures as submitted by the constituents were being perused by higher

level bodies. Hence the recommendations as suggested by the protection

coordination committee and the other subcommittee needed to be given

Minutes of the 24th Protection Coordination Sub Committee Meeting held on 26.09.2013 Page 2

more focus and carried out on priority basis. He also noted that as per

earlier decision, TANTRANSCO was to complete the islanding scheme by

October-2013.

1.6 MS i/c SRPC requested the constituents to furnish the status of

implementation of pending issues and accordingly the same was taken up

for discussion.

2. Confirmation of the Minutes of the 24th Protection Coordination Sub-Committee meeting held on 26th September, 2013 The Minutes of the 24thPCSC meeting were confirmed, since no comments were

received from the constituents.

3. Grid Disturbances in Southern Region 3.1. Generation loss & tripping of 220kV lines at Kothagudam

TPS and Tripping of ICT’s at Khammam substation (i) Date and Time of event 25.09.2013 at 11.45 Hrs

(ii) Location Kothagudam TPS ,Khammam ICTs, Andra Pradesh

(iii) Plant and/or Equipment directly involved

Kothagudam TPS, Khammam ICTs

(iv) Reported Disturbance / Fault

• Triggering incident was a fault in 220kV KTPS-Managuru line-1.

• Running Units # 1, 2,3,4,5,6,8,9&10 tripped. 220kV lines connected to KTPS tripped on Zone-2 from remote ends. ICT’s at Khammam tripped on overload.

• Frequency dropped from 50.11 Hz to 49.71Hz

(v) Generation Loss 1100 MW (vi) Duration of interruption 30 Minutes to 6 Hrs 15 Minutes

(vii) Category GD 1

• The Grid Disturbance analysis as submitted by SRLDC is enclosed as

Annexure-II.

• The Grid Disturbance Report as submitted by APTRANSCO is enclosed as Annexure-III.

Deliberations

• SRLDC informed the forum that data pertaining to this incident had not


been posted by APGENCO and APTRANCO for detailed analysis of the Grid Disturbance.

• APGENCO informed that at Kothagudam TPS one unit was under planned shutdown and another unit tripped on Generator overload.

• APGENCO informed that a jumper got cut on the terminal tower at Kothagudam Thermal Power Station (KTPS) end resulting in arcing followed by phase to ground earth fault.

• It was informed that 3 to 4 jumpers of CVT and other equipment got cut after jumper cut on terminal tower. The CB however did not trip since there was a contact problem with master trip relay. The faulty relay had been replaced with new one. At the same time at remote end, one pole opened while the other poles did not open leading to LBB/BB operation.

• It was noted that LBB had not initiated at KTPS end though the relay was faulty.

• It was informed that 132kV system at KTPS got tripped due to low vacuum in the CB.

• APGENCO said that GT-4 at generator end tripped on O/L and GT-3 tripped on back up O/C.

• SRLDC pointed out that it was a case of relay mal-operation.

• NTPC stated that the load was thrown off due to line tripping. AVR had to take care of the voltage issues of the Generator so that generator did not trip on over voltage.

• SRLDC enquired about the setting of IDMT characteristics for ICTs in SRTS-I of PGCIL.

• PGCIL informed that adjoining utilities should also follow CBIP guidelines. It was noted from PGCIL that the existing setting of 380 ms for DTOC would be increased to 500 ms pending instructions from their management regarding adoption of IDMT settings for ICT.

• KPTCL requested POWERGRID to share its Protection settings with the adjoining utilities for better protection coordination of the SR System. They were also ready to share their settings with the adjoining utilities.

• SRTS I, PGCIL was requested to adopt only IDMT settings for ICTs in all its substations. The DTOC settings could be removed latest by 21.11.2013 and information submitted to SRPC Secretariat.


Recommendations

a) APTRANSCO and APGENCO were requested to send the detailed analysis report of the above incident at the earliest.

b) PCSC forum also requested all the constituents to submit grid disturbance report at the earliest to analyze the Disturbance / Incident to avoid similar occur rence.

c) PCSC forum requested the utilities to share their protection settings with the adjoining utilities also for better protection coordination and to avoid in spurious trippings.

d) Due to lack of proper incident report , Protection coordination Sub Committee decided to send the Protection Expert Group (5 Members) to visit KTPS substation in November 2013 after analyzing the Grid disturbance report to be sent by APGENCO.

e) SRTS I, PGCIL to adopt only IDMT settings for ICTs in all its substations.

3.2 Generation loss and multiple tripping at Vijayawada TPS (i) Date and Time of event 04.10.2013 at 14:55 hrs (ii) Location Vijayawada TPS ,APGENCO ,AP

(iii) Plant and/or Equipment directly involved Vijayawada TPS


• As reported that triggering incident was B Phase CT failure in 220kV VTPS-Narasarapeta line.

• Running Units # 2,3,4,5 &6 and all 220kV feeders connected to Vijayawada TPS tripped on operation of Bus bar protection.

• Frequency dropped from 49.87 Hz to 49.62Hz

(v) Generation loss 900 MW (vi) Duration of interruption (vii) Category GD1

• The Grid Disturbance analysis as submitted by SRLDC is enclosed as Annexure-IV.

• The Grid Disturbance Report as submitted by APTRANSCO isenclosed as Annexure-V.

Deliberations

• SRLDC informed that the tripping analysis report had not been received by them to analyze the Grid Disturbance.

• APTRANSCO informed that 'B' Phase CT had failed in the VTPS-Narasarapeta line.


Recommendations

a) APTRANSCO and APGENCO were requested to send the detailed analysis report of the above incident at the earliest.

b) The Disturbance would be discussed in the 26th PCSC.

4. Grid Incidences

4.1 Tripping of Unit#1 at North Chennai TPS ST2

(i) Date and Time of event 01.10.2013 at 14:50 Hrs

(ii) Location North Chennai TPS ST2,TN

(iii) Plant and/or Equipment directly involved North Chennai TPS


As reported Unit#1 tripped due to operation of differential protection of Unit#1.

(v) Generation loss 600 MW (vi) Duration of interruption (vii) Category GI2

Deliberations

• TANTRANSCO informed that since the plant had not yet been formally handed over to them, it was difficult to get the report from the plant.

• It was noted that there was a CB problem and M/s Areva had attended the same.

• TANTRANSCO informed that the plant was still under outage and its COD too was not yet declared.

• SRLDC stated that the relevant tripping details should be made available to it, as per Regulations.

Recommendations

a) TANTRANSCO was requested to send the detailed analysis report of the above incident at the earliest.

b) The Grid Incidence would be discussed in the 26th PCSC.

4.2 Tripping of HVDC Badrawathi Pole - 1 & 2 (i) Date and Time of event 01.10.2013 at 16:26 Hrs (ii) Location HVDC Badrawathi, PGCIL,AP

(iii) Plant and/or Equipment directly involved

HVDC Badrawathi


• As reported tripping occurred due to auxiliary supply failure.

• Frequency dropped from 49.83 Hz to


49.28Hz (v) Generation loss 1000MW (vi) Duration of interruption 17 Minutes

(vii) Category GI2

Deliberations

• It was informed that failure of auxiliary power supply to HVDC station was the cause of tripping.

• Concerns were raised over the absence of redundancy of auxiliary supply.

• SRLDC queried about status of ins tallation of 315 MVA ICT.

• ED, SRLDC stated that system operator should get the complete tripping reports as per IEGC guidelines. He also informed that SRLDC may not be in a position to certify the availability certification for the interregional links for the above said period with out getting the complete tripping reports.

Recommendations

a) PGCIL was requested to send the detailed analysis report of the above incident at the earliest.

b) The Grid incidence would be discussed in the 26th PCSC.

4.3 Tripping of Unit#7 at Raichur TPS & 400kV BTPS-Raichur line

(i) Date and Time of event 04.10.2013 at 05:49 hrs (ii) Location Raichur TPS, KPCL, Karnataka

(iii) Plant and/or Equipment directly involved Raichur TPS


• As reported fault had occurred in Generator transformer of Unit#7 at Raichur.

• The tripping of 400kV BTPS-Raichur line on Zone-2 from BTPS end needs to be further investigated

(v) Generation loss 210 MW (vi) Duration of interruption (vii) Category GI2

Deliberations

• It was noted that a fault indication was sensed on RTPS- BTPS line. At RTPS end fault indication was in zone 1 while at BTPS end it was in Zone 2 for RTPS Unit 7 GT Failure.

• SRLDC pointed out that line protection should not operate for GT fault. It was reported that GT has failed and no D/R was sent within the stipulated time.


Recommendations

a) KPCL was requested to send the detailed analysis report of the above incident at the earliest.

b) The Grid incidence would be discussed in the 26th PCSC.

5. Status of Pending Protection issues The following pending protection issues were discussed in the 25th PCSC meeting.

SN Recommendation The meeting in which the issue was Discussed

Anticipated date of completion

Agency Status 25th PCSC Deliberations

1 The Main I and Main II Protection of Different make-Sharavathy

21st PCSC held on 25.06.2013

Dec-13 KPCL Pending KPCL informed that the protection issue would be sorted within the agreed time.

2 Replacement of OLD CBs at Sharavathy



3 COMPLIANACE OF 3RD PARTY AUDIT REPORT-Sharavathy

17th PCSC -25th PCSC (26.02.2013 to 22.10.2013)


4 BUSBAR PROTECTION AT KAYATAR 110KV SUBSTATION


Dec-13 TANTRANSCO

Pending TANTRANSCO informed that the protection issue would be sorted within the agreed time.

5 Thermo vision Scanning of Jumpers

22nd PCSC held on 31.07.2013

Dec-13 TANTRANSCO

Pending TANTRANSCO informed that it is an operational issue and requested PCSC forum to put it in the operational agenda.The forum agreed for the same.

6 PROVIDING DR AND EL-MAMIDAPALY

23rd PCSC held on 27.08.2013

Dec-13 APTRANSCO

Pending APTRANSCO informed that the protection issue would be sorted within the agreed time.


7 EARTH PITS at EDAMON

17th PCSC (26.02.2013 )

Mar-14 KSEB Pending KSEB informed that the protection issue would be sorted within the agreed time.

8 DG SET NOT AVAILABLE-EDAMON

17th PCSC (26.02.2013 )

Nov-13 KSEB Pending KSEB informed that the protection issue would be sorted within the agreed time.

9 48 V DC SUPPLY REDUNDANCY NOT AVAILABLE-EDAMON

17th PCSC (26.02.2013 )

Dec-13 KSEB Pending KSEB informed that the protection issue would be sorted within the agreed time.

10 ONLY ONE BUS IS AVAILABLE, TRANSFER BUS SHALL BE PROVIDED -EDAMON

17th PCSC (26.02.2013 )

Mar-14 KSEB Pending KSEB informed that the protection issue would be sorted within the agreed time.

11 CARRIER INTERTRIPPING IS NOT AVAILABLE FOR SBEM 1,2,3 FEEDERS-EDAMON

17th PCSC (26.02.2013 )


12 MAIN2 DISTANCEPROTECTION FOR EMPC#1 FEEDER NOT AVAILABLE-EDAMON

17th PCSC (26.02.2013 )


13 LBB NOT IN SERVICE FOR SBEM 2,3 AND EMPC#1-EDAON

17th PCSC (26.02.2013 )


14 IDMT characteristics for Earth Fault Relay of the GTs in UPCL

24th PCSC 26.09.2013 )

Nov-13 UPCL Pending UPCL and KPTCL were requested to coordinate and change the relay settings.

15 UPCL -Kemar Line Protection would be coordinated by KPTCL and UPCL

24th PCSC 26.09.2013 )

Oct-13 KPTCL/UPCL

Attended KPTCL and UPCL checked the relay settings to avoid trippings like 18.09.2013 incident.


16 Reviewing of Distance Protection relay settings at Hassan by PGCIL SR II

24th PCSC (26.09.2013 )

Oct-13 SR II, PGCIL

Attended Distance Protection relay settings at Hassan was coordinated by PGCIL SR II

17 NPCIL and KPTCL in coordination to review the protection settings at Kaiga

24th PCSC (26.09.2013 )

Nov-13 KPTCL Pending Kaiga,NPCIL and KPTCL were requested to coordinate and change the relay settings.

18 Modification of the present breaker tripping scheme of Haveri line-2 so that the trip coils are activated through two different DC sources

24th PCSC (26.09.2013 )

Dec-13 KPTCL Pending KPTCL informed that the protection issue would be sorted within the agreed time.

19 The non availability of 220 KV and 400 KV bus coupler is affecting the reliability of 400/220 KV Guttur Substation

24th PCSC (26.09.2013 )

Oct-13 KPTCL Pending KPTCL informed that the protection issue would be sorted within the agreed time.

20 Relay/CVT error in 400 KV Kaiga-2 Line

24th PCSC 26.09.2013 )

Oct-13 KPTCL Attended KPTCL informed that the protection issue was sorted out.

21 The non tripping of breaker at Pondy SS would be checked for NLC tripping

23rd PCSC held on 27.08.2013

Oct-13 NLC Attended NLC informed that the protection issue was sorted out.

Deliberations

• The PCSC forum requested the constituents to implement the above protection committee recommendations on priority basis.

6. SPS for Kudankulam Nuclear Power Station SRLDC brought to the notice of the PCSC forum that therehad been re-orientation recently in respect of 400 KV lines emanating from Kudankulam. Three 400kV lines were now from Kudankulam to Thirunelveli while remaining one line is from Kudankulam to Madurai. Hence the following logic was proposed for SPS at Kudankulam on account of the change in the configuration:


Contingency Action

Tripping of all three lines from Kudankulam to Thirunelveli and two units in running condition at Kudankulam.

One unit at Kudankulam to go on house load and the second unit generation would be evacuated through 400kV Kudankulam-Madurai line.

25th PCSC Deliberations

• The PCSC forum requested KKNPP, NPCIL to send the detailed analysis report about the SPS and modifications if any in the SPS as suggested by SRLDC latest by 11.11.2013.

7. Review of Power swing block settings of Distance protection relay

Deliberations

• PCSC forum decided that the issue would be discussed in detail by the Sub Group Meeting to be held on 20.11.2013 (Wednesday) preceding the PCSC meeting.

• Issues relating to Over voltage and staggered tripping and any other Protection relay setting issues may please be sent to the SRPC Secretariat latest by 11.11.2013 to have fruitful discussions in the Sub Group meeting of PCSC.

8. Compliance status of Protection Audit conducted in the Substations of Southern Region Deliberations

• PGCIL informed that regarding Munirabad SS the issue was taken up with KPTCL.

• KPTCL informed that that Main-1 and Main-2 relays have been included in the DPR but however for the same tender has also been called for.

9. Tripping Incidents in the Southern Region

The trippingdetails that had occurred in the Southern Region during the month of September - October 2013 is attached herewith as Annexure-VI. Constituents were requested to update the details in the SRLDC Website at the earliest to analyze the incidents and suggest remedial measures if any.


10. SPS for 400 KV Kolar - Hosur line SRTS II, PGCIL informed that the Original Equipment Manufacturer (OEM, i.e. Siemens) had advised against having too many Logics (in this instance- runback) in the HVDC system.

Deliberations

It was agreed that the SPS for 400 KV Kolar-Hosur Line would be discussed in a Special Meeting to be convened at Kolar SS.

11. Status of implementation: SPS in Southern Region

SN

Name of the Scheme Details of the scheme

Implementing

Agency


PCSC Recommendations

1 Proposed Modification in the SPS at Kolar SS

In the 16th PCSC the forum proposed an additional trip logic (dp/dt )to the Kolar SPS during contingencies similar to New Grid disturbance on 31.07.2012

PGCIL PGCIL informed that the SPS is under Process. Would be completed by end October 2013.

The forum requested PGCIl to complete the modification within the agreed time.

2 Kudankulam SPS

In case of tripping one or two units at Kudankulam nuclear power plant, trip signal-1 or Trip signal-1&2 will be generated depending on number of units tripping. Trip signal-1:793 MW and Trip Signal-2:710 MW

PGCIL Second Mock Exercise was conducted on 29th August 2013.

3 Modification in NTPC Talcher SPS

SPS would be modified to back down all the generating units instead of tripping the units

NTPC New Scheme with SPS 1000 may be kept in service under normal Operating conditions

The PCSC forum requested NLDC/SRLDC to convey the decision at the earliest.

12. Status of implementation: SPS in Andhra Pradesh

SN


Implementing

Agency



1 Vijayawada-Nellore SPS

if one of 400kV Vijayawada-Nellore D/C line trips and before tripping flow each circuit is >550 MW then back down generation or trip one generating unit each at GMR Vemagiri, Gouthami, Konaseema, Jegurupadu-II and Lanco. Total generation back down of 430 MW. Proposed in 9th PCSC (9.07.2010)

PGCIL ./ APTRANSCO/IPPs

PGCIL informed that the SPS would be completed by 10th

November 2013.

The PCSC forum decided to conduct mock exercise on 30th November 2013.


2 Nellore-Almatti SPS

If one of 400kV Nellore-Almatti DC line trips and before tripping flow each circuit is >520 MW then trip one generating unit each at SEPL and MEPL. Total generation back down of 300 MW. Proposed in 15th PCSC (18.07.2012)

PGCIL MEPL sent the confirmation.

The PCSC forum decided to conduct mock exercise on 15th November 2013 at 12:00 Hrs. APTRANSCO was requested to coordinate the Mock exercise with IPPs.

13. Status of implementation: SPS in Karnataka

SN


Implementing

Agency



1 Somanahally& Bangalore water supply

a) To trip all 220kV lines & 220 / 66kV trfs except 220 kV Harohalli & Tataguni lines at Somanahally and to trip Vrishabhavathi line at Tataguni when ICTs at Somanahally trip. b) To trip 220 kV Vajamangala and Madhuvanahally-1 & 2 lines at TK Hally when ICTs at Mysore trip.

KPTCL

KPTCL informed that the Substation feeding configuration. KPTCL is modifying the logic as per the latest configuration.

The PCSC forum requested KPTCL to submit the SPS Logic to the SRPC Secretariat.

14. Status of implementation: SPS in TamilNadu

SN


Implementing

Agency


PCSC Recommendation

s 1 Thirunelveli

SPS To avoid overloading of Thirunelveli ICTs in the contingency of tripping of Thirunelveli-Edamon lines.

TANTRANSCO

TANTRANSCO informed that the scheme was implemented on 20.10.2013.

The forum requested PGCIL / TANTRANSCO to send the scheme details (Logic and SLD) to SRPC Secretariat latest by 11.11.2013.

2 Madurai SPS To avoid overloading of Madurai ICTs.

TANTRANSCO

TANTRANSCO informed that the scheme would be ready by end of October 2013.

The forum requested TANTRANSCO to implement the scheme within the agreed time .

15. Implementation of Islanding schemes in SR Deliberations

The PCSC forum requested TANTRANSCOto implement the remaining part of Stage II of the Islanding Scheme latest by end of October 2013 since other utilities had completed their part.. TANTRANSCO agreed to complete their part by the agreed time line.


16. The issue of AUFR stages and implementation in SR

• In the second NPC Meeting, ithad been agreed that there would be four stages for AUFLS starting with 49.2 Hz. The various stages for AUFLS operation are 49.2 Hz, 49 Hz, 48.8 Hz and 48.6 Hz.

Deliberations

It was noted that all the stages had been implemented except portion of the last stage of 48.6 Hz in TN.

17. Submission of completed dynamic study data

Deliberations

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

• NPCIL, MAPS was requested to submit the dynamic study data of their system.

18. Synchronizing facility for Black start restoration The PCSC forum requested KPTCL to provide synchronizing facility in Hubli S/S within the agreed time (i.e. by August 2014 ).

19. Requirement of Under Voltage Relays (UVR) for SR

The PCSC forum had proposed for the provision of under voltage relays in various low voltage pockets to ensure reliable power supply and grid safety

Ø Constituents were requested to install the UVR at least in a phased manner in the SRLDC specified nodes. Progress in this regard may be reported to the PCSC forum at the earliest.

20. Implementation of recommendations of Grid Disturbance enquiry committee

Deliberations: Healthiness of Batteries: All the constituents were requested to send the status of healthiness of

Batteries to the SRPC Secretariat on monthly basis (i.e by 7th of every month)..

21. Detailed Project Report (DPR)

Deliberations

• KPTCL informed that the implementation of 765 kV system in SR would increase the fault level which may require replacing the existing CBs with new high capacity CBs. KPTCL also informed the forum that in the DPR as sent by the many of the constituents did not include high capacity CBs.


• Hence KPTCL requested for revision in the DPR to include high capacity CB's due to configuration changes in the SR system.

• MS (I/c) suggested that this issue be discussed in the ensuing SRPC Meeting.

22. Remedial measures taken for the critical tripping events in the Southern Region. The constituents were requested to submit the remedial measures taken by them for the critical tripping events sent by SRPC secretariat by filing the remedial measure column of the word file at the earliest to SRPC secretariat.

It was also requested that the complete tripping analysis report with (DR, EL) for the tripping incidents may please uploaded in the SRLDC website.

23. 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 was requested that Agenda Items for the PCSC meetings, if any, may please be sent latest by 5th working day of every month to SRPC Secretariat to compile and circulate the sameso as to have fruitful discussions in the PCSC meetings.

24. Agenda for the Sub Group meeting of PCSC. The following issues would be discussed in the Sub Group meeting the same was communicated vide SRPC Lr. Dated 29.10.2013.

a) Power Swing Blocking Setting of Distance Relays b) Philosophy of Zone 3 Settings (POWERGRID to furnish details) c) Time delays in df/dt Relays d) Changes in over voltage setting if any, for 400 kV lines. (Changes in the

present settings, if any, may please be sent to SRPC Secretariat latest by 11th November 2013).

25. Date & Venue of the next Meeting The 26th PCSC meeting would be conducted on 21.11.2013 (Thursday) preceded by the Sub Group meeting on 20.11.2013.

Member Secretary i/c thanked all the Members &participants for their active contribution in the Meeting.

*****

Rajan1

ANNEXURE I (1/5)

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ANNEXURE I (2/5)

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ANNEXURE I (3/5)

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ANNEXURE I (4/5)

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ANNEXURE I (5/5)

Tripping of Khammam ICT-1&2 at 11:45 hrs on 25th September 2013

SRLDC observations:

FIR reported that ICT’s had tripped on operation of overload protection. It was reported that the

triggering incident was a fault in 220kV KTPS-Manuguru line-1. All the 220kV lines at KTPS tripped

from remote ends on Zone-2 protection.

Figure 1 : SLD of 220kV Khammam switchyard

Rajan1

ANNEXURE II (1/2)

Figure 2 : Gooty 400kV bus voltage from PMU

From Gooty PMU voltage it is observed that fault started at 11:45:05.920 hrs and cleared at

11:45:06.480 hrs i.e., in 560 milli seconds (approx). From D.R of ICT-2 the current in neutral starts

from 11:45:06.155 hrs.

From D.R of ICT-2 it is observed that the current was 1.069 A in Secondary i.e. 1069 Amps (CT Ratio =

1000/1A) and tripped in 450ms. In ICT-1 the maximum current observed was 1.8 A in secondary R

and Y phase i.e. 1800A (CT ratio=1000/1A).

Recommendation and further actions required:

1) It appears that the ICT’s at Khammam have tripped before tripping of 220kV Khammam-

KTPS line-1&2 which was not desired. 220kV Khammam-KTPS line-1&2 should have tripped

in distance Zone-2 protection or on Directional earth fault (for high resistance fault) before

tripping of the ICT’s. The ICT protection needs to be coordinated with 220kV line protection

at 400/220kV Khammam substation.

2) It is to be ensured that the ICT’s have an IDMT characteristics for directional over current

and earth fault and DMT characteristic’s for high set of directional over current and earth

fault.

3) The D.R of ICT-1 is not time synchronized with GPS and same needs to be rectified.

Rajan1

ANNEXURE II (2/2)

TRANSMISSION CORPORATION OF ANDHRA PRADESH LIMITED

FAX MASSAGE DATED 25.09.2013

From To The Chief Engineer/ 1) The Member Secretary, Power Systems, SRPC, APTRANSCO, 29, Race Course Road Vidyut Soudha, Hyderabad. Bangalore-560009.

2) The Executive Director, SRLDC, 29, Race Course Road Bangalore-560009.

Lr.No.CPS/SP/111 /SRPC-FAX/Vol.3/D.No. 569/13, Dt: 26.09.2013 Sir,

Sub: Grid breaker tripping at 11:46 Hrs on 25.09.2013 at KTPS - Reg.

>>*<<

INCIDENT: It is reported that at 11:46 Hrs on 25.09.2013, a heavy fault occurred on 220 KV KTS-Manuguru –I

feeder and the conductors snapped at the following locations:

1. Yph conductor snapped between Tower locations 1 and 2.

2. Rph CVT jumper got cut.

3. Yph conductor got cut after the line isolator.

4. Bph jumper at the wave trap.

5. Rph jumper between line-in isolator and breaker.

Due to the above incidents the following units and feeders got tripped:

At KTS(O&M):

• The 220KV Nunna, Miryalaguda, Manuguru-1&2 and Lower sileru feeders from KTS(O&M)

tripped on Zone-2 at remote ends.

• Also, the busbar protection operated, tripping all the 220 KV feeders and Units 2-8 at

KTS(O&M)

At KTS-V Stage:

• The 220KV Budidampadu-1&2, Seetharampatnam-1&2 and Lowersileru feeders from KTS-V

stage tripped at other ends on Zone-2. Also, the units 9 and 10 are tripped at KTS-V

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ANNEXURE III (1/2)

RESTORATION:

• By 12:15 Hrs the 220 KV KTS-V - Lower sileru and KTS-V – Budidampadu 1&2 were taken in to

service

• By 12:15 Hrs the 220 KV Shapurnagar, Lower sileru and Miryalaguda feeders from KTS(O&M) were

taken into service.

• At 14:05 Hrs Unit-2 was synchronized at KTS(O&M)

• At 14:05 Hrs the 220 KV KTS-Manuguru – II feeder was taken into service.

• At 14:18 Hrs the Unit-10 was synchronized at KTS-V.

• At 14:30 Hrs the Unit-4 was synchronized at KTS(O&M).

• At 14:37 Hrs, the Unit-8 was synchronized at KTS(O&M).

• At 14:53 Hrs, the Unit-9 was synchronized at KTS-V




This is for the favour of information please.

CHIEF ENGINEER POWER SYSTEMSt

Rajan1

ANNEXURE III (2/2)

Tripping of running units at Vijayawada TPS

at 14:55 hrs on 4-10-2013

Running units-2,3,4,5&6 at Vijayawada TPS (connected at 220kV) tripped at 14:55 hrs on

4-10-2013 (Unit#1 was under shutdown).

The generation loss was 900MW and change in frequency was 0.25 Hz

Rajan1

ANNEXURE IV (1/2)

Analysis of the incident:

From synchrophasor data of Ramagundam it can be observed that two faults had occurred,

1st in B-Phase which was immediately followed by a fault in R-Phase. Both the faults were

timely cleared.

As per FIR of APTRANSCO the triggering incident was failure of triggering incident was B

phase CT failure in 220kV VTPS-Narsaraopeta line at VTPS end. During discussion of the

tripping in 25th protection sub-committee meeting of SRPC on 22-10-2013, it was informed

by APTRANSCO representative that CT failure had also occurred in 220kV VTPS-Podili line at

VTPS end. The 220kV Nasaraopeta line is connected to 220kV bus-2 and 220kV Podili line to

220kV Bus-1 at VTPS. Bus-bar protection of both the buses got acted due to failure of above

CT’s .

D.R, E.L and final trip report not furnished by APTRANSCO/ APGENCO.

Rajan1

ANNEXURE IV (2/2)

TRANSMISSION CORPORATION OF ANDHRA PRADESH LIMITED

FAX MASSAGE DATED 05.10.2013

From To The Chief Engineer/ 1) The Member Secretary, Power Systems, SRPC, APTRANSCO, 29, Race Course Road Vidyut Soudha, Hyderabad. Bangalore-560009.

2) The Executive Director, SRLDC, 29, Race Course Road Bangalore-560009.

Lr.No.CPS/SP/111 /SRPC-FAX/Vol.26/D.No. 590/13, Dt:05.10.2013 Sir,

Sub: Grid breaker trippings on 04.10.2013 - Reg.

>>*<<

Sl. No.

Tripping Element

Type

Element

Remarks

Normalisation

Date Time (Hrs:mm) Date

Time (Hrs:mm)

1. 04.10.2013 14:56 220kV Line

220kV VTS- Narasaraopeta feeder

The B-Phase CT on 220kV VTS- Narasaraopeta feeder got blasted at VTS end. The fault got cleared by the operation of Busbar protection, tripped all the 220kV feeders and units connected to Bus-1 & Bus-2.

Failed CT to be replaced

CHIEF ENGINEER POWER SYSTEMSt

Rajan1

ANNEXURE V (1/1)

Pending Tripping Details for Month of SEP-OCT 2013 ANNEXURE VI

SN ELEMENT NAME TRIPPING DATE

TRIPPING TIME

FIR (S) DR (S) EL (S) FIR (R) DR (R) EL (R) DETAILS

1 400 kV VIJAYAWADA - VEMAGIRI 1 22-Oct-13 2:59

2400 kV RAMAGUNDAM -

HYDERABAD 4 22-Oct-13 2:58

3400 kV VEMAGIRI - GOUTHAMI

CCCP 1 22-Oct-13 2:29

4 400 kV MYSORE - HASAN 2 21-Oct-13 23:58

5 400 kV NELLORE - ALAMATHI 21-Oct-13 2:59

6400 kV TIRUNELVELI -

KUDAMKULAM 4 21-Oct-13 2:58

7 400 Kv KOLAR - SPDR 20-Oct-13 23:03


9400 Kv GAJWEL - BHOOPALAPALLY

1 20-Oct-13 2:45

10400 kV WARANGAL - BOOPALPPALLI

2 20-Oct-13 2:45


12 400 Kv GOOTY - NPS 2 19-Oct-13 16:03

13 220 kV SEDAM - TANDUR 17-Oct-13 13:01

14 400 kV HYDERABAD - N'SAGAR 17-Oct-13 12:32

15 400 kV KAIGA - GUTTUR 2 17-Oct-13 3:49


17 400 kV MADURAI - PUGALUR 1 16-Oct-13 21:04

18 400 kV MADURAI - TIRUNELVELI 16-Oct-13 21:04

19 220 kV KANIAMPET - KADAKOLA 16-Oct-13 12:48


21 220 kV AMBEWADI - PONDA 2 16-Oct-13 11:34

22 400 Kv KLVDPT - VALLUR 1 13-Oct-13 19:03

23HVDC TALCHER - KOLAR POLE 1 AT

TALCHER 13-Oct-13 1:19






27 220 kV EDAMON - EDAPPON 11-Oct-13 12:57

28 400 Kv NCTPS - VALLUR 2 10-Oct-13 16:05

29 400/220 kV ICT-1 AT CHITTOOR 9-Oct-13 13:48

30 400/220 kV ICT-1 AT CUDDAPAH 9-Oct-13 12:00


32 400 kV KURNOOL - SRISAILAM 8-Oct-13 15:53

33 400 kV SRISAILAM-MAMIDIPALLI 2 8-Oct-13 15:51

34 400 Kv TRICHUR - KOCHI 1 8-Oct-13 13:31



37 400/220 kV ICT-1 AT N'SAGAR 7-Oct-13 23:57

38 400 kV KALPAKKA - VEMAGIRI 1 7-Oct-13 17:57

39 400 kV VTPS IV - SRISAILAM 2 7-Oct-13 17:57



42 400 kV KALPAKKA - VEMAGIRI 1 7-Oct-13 14:03


44 400/220 kV ICT-2 AT GOOTY 6-Oct-13 12:56

: File Avilable and Received Within 24 Hrs.: File Avilable and Received after 24 Hrs.

(S): SENDER END

: File Not Avilable.

(R): RECEIVER END

1

Rajan1

ANNEXURE VI (1/4)



46 220 kV KANIAMPET - KADAKOLA 6-Oct-13 11:52

47 400 kV TALAGUPPA - HASSAN 5-Oct-13 22:50

48 VIJAYAWADA TPS-UNIT 2 4-Oct-13 14:56





53400 kV MAHABOOB NAGAR -

RAICHUR 4-Oct-13 10:25

54400 Kv GAJWEL - BHOOPALAPALLY

2 3-Oct-13 16:13

55400 kV VEMAGIRI - GOUTHAMI

CCCP 2 3-Oct-13 15:18

56400/230 Kv ICT-1 AT SUNGUVARCHATRAM 3-Oct-13 15:02


58 400 kV VIJAYAWADA - VTPS IV 2 3-Oct-13 6:49

59 GOOTY-SOMANAHALLI AT GOOTY 3-Oct-13 3:43

60400 kV NEYVELI TS 2-

PONDICHERY 2-Oct-13 23:48

61400 Kv PONDICHERY -

SPCHATRAM 2-Oct-13 23:48


63220 kV GUMMUDIPUNDI -

SULLURPET 2-Oct-13 14:00

64 HVDC BHADRAVATHI POLE 1 1-Oct-13 16:28

65 HVDC BHADRAVATHI POLE 2 1-Oct-13 16:28





68 220 kV AMBEWADI - PONDA 1 29-Sep-13 21:47:00

69 220 kV KAIGA - KODASALLY 29-Sep-13 21:47:00

70 400 kV MYSORE - HASAN 2 29-Sep-13 17:59:00

71 400 kV KAIGA - GUTTUR 2 29-Sep-13 15:12:00

72400 kV KHAMMAM - MAMIDIPALLY

1 28-Sep-13 19:44:00


74 220 kV KANIAMPET - KADAKOLA 28-Sep-13 12:08:00

75 220 kV IDUKKI - UDUMALPET 27-Sep-13 13:07:00


KUDAMKULAM 3 27-Sep-13 12:41:00

77 400/220 kV ICT-1 AT KHAMMAM 25-Sep-13 11:45:00

78 400/220 kV ICT-2 AT KHAMMAM 25-Sep-13 11:45:00

79 400 kV TALAGUPPA - HASSAN 24-Sep-13 22:17:00

80 400/230 kV ICT-1 AT NEYVELI 24-Sep-13 14:06:00


82 400 Kv HASSAN - UPCL 2 23-Sep-13 23:44:00

83 400 Kv GOOTY - NPS 1 22-Sep-13 3:02:00

84 400 kV RAMAGUNDAM - GAJWEL 20-Sep-13 17:09:00

85 220 kV SEDAM - TANDUR 20-Sep-13 7:23:00

86 400 kV VTPS IV - SRISAILAM 2 19-Sep-13 10:05:00

87 400 Kv VTPS - MALKARAM 2 19-Sep-13 9:54:00



90 400 kV KAIGA - NARENDRA 1 18-Sep-13 23:20:00



93 400 kV RAMAGUNDAM - N'SAGAR 1 18-Sep-13 3:23:00

94 400 kV MADURAI - PUGALUR 1 17-Sep-13 15:01:00

2

Rajan1

ANNEXURE VI (2/4)


95 400 Kv HIRIYUR-BTPS 1 17-Sep-13 4:33:00


97 400 kV GOOTY - NELAMANGALA 16-Sep-13 23:16:00

98 400/220 kV ICT-2 AT CUDDAPAH 16-Sep-13 4:14:00

99 400/220 kV ICT-1 AT CUDDAPAH 16-Sep-13 4:14:00

100 400 kV GUTTUR - HIRIYUR 1 16-Sep-13 1:56:00

101 400 Kv GOOTY - NPS 1 16-Sep-13 0:01:00


103 220 kV CHITTOR - THIRUVALEM 15-Sep-13 22:45:00

104 400 kV GUTTUR - NARENDRA 1 15-Sep-13 0:01:00

105 400 kV KAIGA - NARENDRA 1 15-Sep-13 0:01:00


107400/230 kV ICT 1 AT

PONDYCHERRY 13-Sep-13 12:52:00

108 400 kV HASSAN - NEELAMANGALA 1 13-Sep-13 3:02:00



111 400 Kv GOOTY - NPS 2 12-Sep-13 2:55:00

112 400/220 kV ICT-1 AT HOODY 12-Sep-13 0:04:00



115 400 kV VIJAYAWADA - NELLORE 1 10-Sep-13 3:04:00

116400 Kv KRISHNAPATNAM -

NELLORE 1 10-Sep-13 3:04:00

117 400 Kv NPS - NELLORE -2 10-Sep-13 3:04:00


119 400 Kv GOOTY - NPS 2 10-Sep-13 3:04:00

120 400 kV KURNOOL - GOOTY 10-Sep-13 3:04:00

121 400 kV NELLORE - ALAMATHI 10-Sep-13 3:04:00

122 400 Kv NELLORE - SPDR 10-Sep-13 3:04:00







NELLORE 2 9-Sep-13 1:34:00

129 400 kV NELLORE - ALAMATHI 9-Sep-13 1:34:00







136 400/220 kV ICT-2 AT N'SAGAR 7-Sep-13 17:16:00

137 400 kV RAMAGUNDAM - N'SAGAR 1 7-Sep-13 17:16:00

138 220 kV SEDAM - TANDUR 7-Sep-13 0:13:00


140 220 kV PONDYCHERRY- VILLIANUR 5-Sep-13 18:51:00

141 400 Kv GOOTY - NPS 2 4-Sep-13 0:24:00


143 400 Kv KOLAR - SPDR 3-Sep-13 23:58:00



146 400/220 kV ICT-1 AT HYDERABAD 3-Sep-13 18:15:00

147 220 kV KANIAMPET - KADAKOLA 3-Sep-13 12:57:00


149 400 kV TALAGUPPA - HASSAN 1 2-Sep-13 22:42:00

3

Rajan1

ANNEXURE VI (3/4)


150 400 Kv HIRIYUR-BTPS 2 2-Sep-13 22:36:00


152 400/220 kV ICT-1 AT GUTTUR 2-Sep-13 11:41:00

153 400/220 kV ICT-2 AT GUTTUR 2-Sep-13 11:41:00

154400 kV UDUMALPET - TIRUNELVELI

1 1-Sep-13 17:59:00



NELLORE 1 1-Sep-13 2:13:00




4

Rajan1

ANNEXURE VI (4/4)

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