SOUTHERN REGIONAL POWER COMMITTEE - Karnataka · held on 31st July 2013 in the Conference Hall of Southern Regional Power Committee, Bangalore. The list of participants for the PCSC

SOUTHERN REGIONAL POWER COMMITTEE BANGALORE

Minutes of the 22nd Meeting of Protection Coordination Sub- Committee

of SRPC held on 31.07.2013 (Wednesday)

1. Introduction

1.1 The 22nd meeting of Protection Coordination Sub-Committee (PCSC) was

held on 31st July 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 all the members

and participants to the 22nd meeting of the Protection Coordination Sub-

Committee.

1.3 Member Secretary (I/c), SRPC informed the forum that instances of

trippings were also being monitored by higher bodies. He briefed the forum

about three grid incidents that had occurred in Nellore Pooling Station

(NPS), Somanahalli 220 KV S/S and Raichur on 15.07.2013, 18.07.2013

and 26.07.2013 respectively. He added that in accordance with CEA

guidelines for operating the grid in a secure manner during summer season,

Protection Expert Committee Members had visited NPS and Somanahalli

SS. The recommendations of the Expert Committee had been forwarded to

the respective utilities for needful and necessary compliance.

1.4 MS (I/c), SRPC stated that the Somanahalli substation incident that had

occurred on 15.07.2013 during which commutation failures at HVDC Kolar

had also taken place needed further deliberations. Further, the issue

regarding Definite Time over Current (DTOC) Settings in respect of 400 KV

Somanahalli ICTs also needed discussions.

1.5 MS (I/c), SRPC also appraised the forum about the decision taken in the

second meeting of the National Power Committee (NPC) regarding UFRs

settings. NPC forum had recommended four stages of settings of UFR

Minutes of the 22nd Protection Coordination Sub Committee Meeting held on 31.07.2013 Page 2

relays at 49.2 Hz, 49.0 Hz, 48.8 Hz and 48.6 Hz so as to have uniformity in

all grids.

1.6 MS (I/c) added that regarding formation of Expert Committee to analyze

major trippings in Southern Region, except APGENCO ,all other

constituents had communicated their nominations to the same. He

requested APGENCO also to kindly intimate their nominations to the Expert

Committee. He also stated that data pertaining to line loadings etc, in the

formats already circulated needed to be validated by the constituents. Data

relating to Zone-3 settings or over-current settings interfering with line

loadability had to be validated and submitted.

1.7 MS (I/c) said that as the forum was kindly aware, Logic Analysis / complete

checking of Substation Protection Logic in respect of 10 critical substations

in the region (i.e. critical audit of protection system) had been approved in

the 22nd SRPC meeting held at Bangalore on 18.05.2013. Works in this

regard would need to be taken up at the earliest.

2. Confirmation of the Minutes of the 21st Protection Coordination Sub-Committee meeting held on 25th June, 2013

The following additional information submitted by NTPC regarding the grid

incident that had occurred on 07.06.2013 at Simhadri was noted by the PCSC

forum:

(a) NTPC Simhadri Unit#2 TG tripped on 07.06.2013 at 10:48 Hrs on

"Turbine exhaust hood temperature hi-hi protection".

(b) Unit#2 Boiler was hand tripped at 10:48 Hrs since the LP by-pass did

not opened after turbine tripping.

Deliberations

• ED, SRLDC stated that in the 21st PCSC Meeting, the forum had

requested NTPC, Simhadri to submit the OEM (BHEL Report) report

along with the complete tripping analysis report.

Recommendations

Ø The PCSC forum requested NTPC to submit the OEM's report with

respect to 07.06.2013 incident at the earliest.


3. Status of recommendations of earlier Meetings Status of implementation of PCSC recommendation with regard to earlier trippings is enclosed in Annexure – I A . Annexure IB gives the trippings that have occurred from 8th July 2013. The constituents may please give the remedial measures urgently.

Deliberations

• It had been decided in the 22nd PCSC that all constituents would submit the

status of implementation/update of the recommendations of previous

meetings to SRPC/SRLDC during the forthcoming PCSC.

Recommendations

Ø The PCSC forum recommended that all constituents to submit updates of

Status of implementation to the Protection Coordination Sub Committee by

letter / mail well before the forthcoming Protection Coordination Sub

committee.

4. Status of recommendations of the Working Group / 21st PCSC meetings

The status of implementation of the following recommendations was discussed

in the PCSC meeting.

Deliberations

• Directional Earth Fault (DEF) relay: All 400 KV lines should have IDMT characteristics with a time delay of zone-3 time + 200 ms. DEF would operate within 1.7 sec delay if earth fault current exceeds 20 times the normal value. DEF to be blocked if distance protection picks up. Back up Earth fault of ICTs should have IDMT characteristics - All Constituents.

• Implementation of IDMT settings for Back up Over current relays of ICTs in PGCIL, SRTS-I Sub stations: PGCIL had informed in the 21st PCSC that they would implement the IDMT settings in a week's time – SRTS I,PGCL vide Lr No 14.08.2013 (Annexure IC) requested adjoining utilities to confirm the p rovision of 220 KV Bus bar Protection scheme and carrier aided protection scheme in the downstream for implementing the IDMT settings in the their ICTs .

• Uniform philosophy in respect of Zone 3 protection: Decision to be taken as per recommendations of Task Force.

• All instances of over voltage protection operation to be examined in detail. Pick up to drop ratio of over voltage protection to be kept as close to one


as possible - All constituents to check over voltage settings and implement voltage and time staggering as specified by OCC/PCSC.

Recommendations

Ø The PCSC forum requested all constituents to implement the above recommendations and submit the compliance report latest by 23.08.2013 to the PCSC forum.

5. Status of the recommendations of Special Meeting held on 07.06.2013 Deliberations

• TANTRANSCO informed that Abishekapatty (Tirunelveli S/S) SPS and Madurai SPS were under implementation.

• PCSC requested TANTRANSCO to implement wind blocking from Viranam, Udayathur, Sankari and Kayathar 230 KV S/S if logic of Thirunelveli SPS is met to obtain wind injection blocking of about 300-350 MW towards Tirunelveli S/S. TANTRANSCO informed that Codes from Tirunelveli would be taken and extended to radial feeders available in these 230 KV S/S for wind blocking. TANTRANSCO informed that the work would be completed by Aug 31st 2013.

• The forum requested TANTRANSCO to inform status of the following recommendations latest by 23.08.2013:

o Status Regarding LVRT settings for wind turbines.

o Reactive power compensation with Wind Generators in Udumalpet area. Action plan/progress to be furnished to PCC/OCC.

o SPS to be planned keeping in view the Kudankulam generation, open condition of Kudankulam 400/230 kV ICT and also high wind injection conditions. Results of the study would be conveyed within one month. In the interim period, pre-identified contingency plan with manual action would be finalized and implemented to avert any incident, since each of the 4 TANTRANSCO 230 kV lines is heavily overloaded. Contingency plan with post-Kudankulam injection scenario would also be finalized in line with deliberations in TCC/SRPC meeting .

o Preventive maintenance of lines and substations in the high wind injection area.

o Preventive action to curtail any operation below 380 kV. This would include shedding of pre-identified high reactive loads.

o Furnishing the progress of the wind evacuation system under implementation.


o Examination of df/dt & UFR since some UFR operation had been reported, though the frequency had only touched 49.18 Hz (1st stage UFR 49 Hz) .

Recommendations

Ø In the PCSC meeting it was decided to conduct a Special Meeting on wind generation protection with representatives of Wind Mill Manufacturers, Wind Generators etc. The date of that meeting would be communicated in due course.

6. Status of recommendations regarding Grid Disturbance on 13.06.2013 at Sharavathy generating station-S/S

Deliberations

• KPCL informed the status with respect to the following recommendations.

o Main-I and Main-II Protection to be of Different make - R&M of Sharavathy S/S had been included in DPR.

o Periodic testing of all relays/protection equipment in Sharavathy 220 KV substation - Carried out.

o DEF feature to be enabled for the parallel lines emanating from Sharavathy 220 KV S/S – To be enabled.

o Distance protection settings to be reviewed with respect to line loadability - Reviewed.

o Enabling the Watch dog feature in the protection relay - Enabled.

o Existing old BOCBs to be replaced with hybrid breakers, since sectionalizer breakers are very vital while clearing very high level bus faults - Included in the DPR.

• KPCL informed that provision of different kind of relays for Main I and Main II was posing problem to them in the tendering process.

• APTRANSCO informed that they had also faced similar issue, which had been sorted out through management approval. MS (I/c) requested APTRANSCO to forward copy of the same to SRPC for circulation among the constituents so as to similarly obtain their management's approval for providing Main I and Main II relays of different make.

• The letter forwarded by APTRANSCO (Annexure II) is enclosed for the concerned utilities to obtain their management's approval for provision of Main I & Main II protection schemes of different makes.

• KPCL informed the forum that the Directional Earth Fault (DEF) for parallel lines would be provided within a month's time.


Recommendations

Ø Member Secretary informed the forum that in the NPC meeting it had been informed that in respect of the consolidated DPR submitted to MOP, funding from PSDF had been proposed at 20% , keeping in view the portion of the amount parked in the PSDF that could be utilized for R&M works. It had also been decided that the states would immediately take up renovation and upgradation of protection systems as mentioned in the respective DPRs without waiting for funds from the centre.

Ø Constituents were requested to carry out Protection R&M and Upgradation related works on priority basis as decided in the NPC Meeting.

7. Status of recommendations regarding Grid Disturbance on 17.06.2013 at Kodasalli Generating Station S/S

Deliberations

KPCL informed that constraints in providing bus coupler at Kodasalli 220 KV S/S to avoid similar Occurrences like 17.06.2013 would be presented in the 23rd PCSC meeting.

Recommendations

Ø The forum requested KPCL to present the studies and facts in the forth coming PCSC meeting.

8. Status of recommendations regarding Grid Incidence on

07.06.2013 at 230/110 KV Kayathar substation and multiple tripping incidences in SR.

Deliberations

• TANTRANSCO had agreed to provide Bus bar protection at Kayathar S/S within six months' time - By the end of Dec 2013.

• NTPC, Simhadri which had been requested to submit the complete tripping analysis report (with BHEL report) within a month's time – had submitted its report but was yet to submit the OEM report.

• PCSC forum recommended for thermo vision scanning of jumpers etc in all the substations at the start of the wind generation season. TANTRANSCO informed that the issue was taken up by them to procure three numbers of thermo vision camera for usage in Chennai, Madurai and Erode areas.


Recommendations

Ø The forum requested TANTRANSCO to please provide the Bus Bar protection scheme at Kayathar within the agreed time.

Ø The forum requested NTPC, Simhadri to submit the OEM's (BHEL) report at the earliest in respect of the 07.06.2013 incident at NTPC, Simhadri.

9. Status of recommendations regarding Grid Incidence on 17.06.2013 at 400 KV Kurnool substation

Deliberations

Working of Disturbance recorder and event logger at Kurnool Substation -

APTRANSCO informed that the provision of DR had been included in the

DPR.

10. Status of recommendations regarding Grid Incidence on 18.06.2013 at Ghanapur 400 KV Substation

Deliberations

Checking healthiness of PLCC at 400 kV Ghanapur & Mamidipally

Substations- APTRANSCO and PGCIL informed that they had checked the

same and reported healthy. PGCIL SR-II informed that the Faulty Logic card

of channel one has been replaced by APTRANSCO but channel two Logic

card had been found faulty.

APTRANSCO informed that they would revert back regarding channel two

faulty logic card.

Recommendations

Ø The forum requested APTRANSCO to present the facts in the forth coming PCSC meeting.

11. Status of recommendations regarding Grid Incidence on 21.06.2013 at 400 KV Raichur – Gooty - I line

Deliberations Inspection Compliance Report of circuit breaker at Raichur end

- PGCIL, SRTS I informed that there was relay setting problem in the Line &

not with the Circuit Breaker.

• ED, SRLDC informed that testing of relays was to be taken up urgently and requested to test the relay latest by 01.08.2013.

• ED, SRLDC also informed the forum that, in future for the sake of


secure operation of the grid, SRLDC would keep any such element out, until the relay settings of the element etc was rectified.

Recommendations

The PCSC forum requested SRTS-I, PGCIL to test the relay settings

and the protection equipments at the earliest and submit the

compliance report at the earliest.

12. Details of Grid Disturbances & Incidences

• It had been brought to notice that many of the utilities were not yet

submitting complete tripping reports for the trippings in their system

and the DR/EL printouts.

• SRLDC had earlier informed the forum that unless SRLDC received the complete tripping reports as stipulated in the IEGC i.e. within 24 hours they would not be in a position to certify the Transmission Availability data in future.

• It was also informed in the Meeting that all Tripping details received by the SRLDC would be posted in their Website and the compliance or otherwise would be displayed as Green or Red in the website.

• A snapshot of the SRLDC Website Display is given below for ready reference.

• All major tripping events and the remedial action taken for the

tripping were being monitored by higher bodies regularly.

• SRLDC requested the constituents to submit the First Information Report of the Grid Occurrence immediately and also submit the DR, EL and other details as stipulated in the IEGC(i.e. within 24 Hours).


Recommendations

Ø The constituents were once again requested to submit the detailed Report/Analysis of the Grid disturbances/Major Grid occurrences in the format within 24 hours of the occurrence (by Mail/Fax in the format - Annexure III) with DR, EL, SLD print outs.

13. Grid Disturbances in the southern region

13.1 Grid Disturbance on 15.07.2013 at Nellore Pooling Station

(i) Date and Time of event 15.07.2013 at 21:47 Hrs (ii) Location Nellore, Andhra Pradesh

(iii) Plant and/or Equipment directly involved 400 KV PGCIL Pooling Substation

(iv) Reported Disturbance / Fault:

(a) 400kV Nellore PS - Nellore ckt-1 & 2 (b) 400kV Nellore PS – Gooty-1 was not in service. (kept opened due to voltage regulation) (c) 400kV Nellore PS - Gooty-2 line (d) 400kV Nellore PS - SEPL line (e) Running units at SEPL & MEPL

(v) Generation Loss (a) MEPL : 139 MW (b) SEPL : 260 MW Total : 399 MW

(vi) Duration of interruption 1 Hours 10 Minutes to 9 Hr 30 Minutes (vii) Category GD 1

• The Grid Disturbance analysis as submitted by SRLDC is enclosed

herewith as Annexure IV.

• The recommendations of the Protection Expert committee Meeting held on

24.06.2013 at NPS is enclosed herewith as Annexure V.

• The Compliance Report submitted by SRTS-I, PGCIL is enclosed herewith

as Annexure VI.

Deliberations

• The Nellore Polling Station (NPS), Outage was briefed by SRLDC

• It was noted that the utilities (i.e. SRTS I/PGCIL, SEPL and MEPL) had

not revised their protection settings after the commissioning of NPS during

the month of April 2013.

• MEPL informed that they received DT from NPS on O/V protection which

SEPL did not receive.

• PGCIL SR-I informed that Auto reclosure lockout breaker signal was not


received by NPS. On enquiry of PCSC forum about auto reclosure failure

on R phase from Nellore end, PGCIL SR-I said they would revert back.

• PCSC forum requested the above constituents to revise protection

settings as per the modified system configuration and also intimate the

same to the adjoining utilities so as to have proper protection coordination.

• The PCSC forum was also of the opinion that for 400 KV Lines of less

than 10 Km and 220/230 KV line of less than 3 KM, line differential

protection scheme would be used and in event of communication channel

failure, distance protection will be used as back up.

• APTRANSCO informed that the cable capacitance will restrict the length

of pilot communication between two stations.

• ED, SRLDC suggested that Optical Ground Wire (OPGW) would address

these constraints.

Recommendations

Ø 400 KV Lines of length less than 10 Km and 220/230 KV line with less

than 3 KM would have Line Differential Protection Scheme which would be

taken over by Distance protection on communication link failure. .

Ø PCSC forum requested SRTS I/PGCIL, SEPL and MEPL to implement the

above recommendations and also the protection experts committee

meeting's recommendations. The compliance report may please be sent

to SRLDC/SRPC latest by 23.08.2013.

Ø PGCIL to submit report on failure of auto reclosure from both end of NPS-

Nellore 400 KV Line.

Ø SEPL end LBB had configuration error which needed to be rectified. In

addition, they had to review their GT-2 51 NGT relay settings.

Ø PGCIL SR-I, MEPL and SEPL has to correct distance protection settings

in line with network configuration change.

Ø PGCIL SR-I to check O/V Protection at NPS Station.

Ø ALL DR/EL to be GPS synchronized.


13.2 Grid Disturbance at Somanahalli 220 KV SS on 18.07.2013

(i) Date and Time of event 18.07.2013 at 13:34 Hrs (ii) Location Bangalore, Karnataka

(iii) Plant and/or Equipment directly involved Somanahalli SS Become Dead


On load opening of an isolator in 220 kV switchyard during 220 KV bus change over caused a phase to phase fault. The 400/220 kV ICT’s and 220kV lines tripped on operation of back up protection.

(v) Load Loss 529 MW (vi) Duration of interruption 20 Minutes to 1 Hour 20 Minutes (vii) Category GD 1 • The Grid Disturbance analysis as submitted by SRLDC is enclosed

herewith as Annexure VII.

• The recommendations of the Protection Expert committee meeting held on

26.06.2013 at Somanahalli SS is enclosed as Annexure VIII.

Deliberations

• KPTCL informed that 220kV Bus Bar Protection had been kept out of

service during 220 kV bus changeover process, as per OEM suggestions.

• When they attempted to open North bus GOS of ICT-2 bay, isolator arced

over due to opening of 30 MW of load which was fed from North bus

radially and caused tripping of ICT-1 and ICT-2.

• It was informed that ICT-1 and ICT-2 were feeding approximately 500 MW

of load during the above instance.

• KPTCL informed that at 13.42 Hrs 220 kV TK Hally line was charged at

Somanahally and supply was taken to the bus.

• At 13.57 Hrs PGCIL charged the 500 MVA ICT-1 & 2 one after the other.

• SRTS-II, PGCIL informed that due to the Somanahalli tripping four

instances of Commutation failure had occurred in the HVDC Kolar link on

that day. They have also informed that if the commutation failures had

occurred few more time, it could have led to tripping of the HVDC Link.

• In view of the above facts SRTS II, PGCIL requested for enabling Definite

Time Over Current (DTOC) settings in the Somanahalli, 400 KV ICTs until

the R&M works at Somanahalli is fully completed.


• KPTCL informed the forum that KPTCL and PGCIL would have one to one

meeting and decide about enabling the DTOC or IDMT settings with Bus

Bar Protection etc and inform the outcome of the meeting to the PCSC

forum.

• KPTCL informed that they would take the matter to keep the bus bar

protection in service during bus change over under OEM procedure.

• KSEB informed that High impedance contact relay be used in Bus bar

protection.

• Superintending Engineer (P), SRPC informed the forum that as per

provisions of IS:9921 (Part I), disconnector (isolator) for 420 KV rating

could make or break only if there is a negligible current flow (i.e. less than

0.5 A).

• The Constituents informed the forum that it was the normal practice of the

utilities to keep both the bus isolators briefly ON during the bus

changeover and open the other isolator. This would not create any arc as

only one of the parallel current carrying paths broken and the other path to

supply the load current.

• Superintending Engineer (P), SRPC also highlighted that the as per IE

Rules (now CEA's Measures relating to Safety and Electricity supply-

Regulations, 2010) suitable interlock had to be provided between isolator

and corresponding circuit breaker to prevent isolator opening on load.

• The forum opined that the relevant Safety Regulations and established

procedures needed to be followed to avoid such outages.

• MS (I/c) said that the recommendations of the expert group meeting held

on 26.07.2013 at Somanahalli should be implemented at the earliest.

Recommendations

Ø The PCSC forum requested KPTCL to carry out the recommendations of

the expert group meeting and submit the compliance report latest by

23.08.2013 to the PCSC forum.

Ø The outcome of the KPTCL /PGCIL meeting regarding enabling of DTOC

settings at Somanahalli SS would be informed to PCSC forum with the

agreed time.


Ø All constituents to use interlocks in isolators.

13.3 Multiple trippings occurred in SR on 18.07.2013

(i) Date and Time of event 18.07.2013 at 13:34 Hrs (ii) Location Bangalore, Karnataka

(iii) Plant and/or Equipment directly involved Somanahalli SS Become Dead


1. 400/220kV ICT-1&2 at Somanahalli SS 2. 400kv Hiriyur-Nelamangala-1 3. 400kV Hassan-UPCL-1 4. 400kV Raichur-Gooty-1 5. 400kV Raichur- Mehaboob nagar 6. 400kV Guttur-Hiriyur-1 7. 400kV Mehaboob nagar-Nagarjunasagar

(v) Load Loss - (vi) Duration of interruption 20 Minutes to 1 Hour 20 Minutes (vii) Category GD 1 • The preliminary Grid Disturbance analysis as submitted by SRLDC is

enclosed herewith as Annexure IX.

Recommendations

• The PCSC forum requested KPTCL, SRTS I &II/PGCIL, to submit the

detailed tripping analysis report to SRLDC/SRPC for analysis.

13.4 Grid Disturbance at RTPS on 26.07.2013

(i) Date and Time of event 26.07.2013 at 11:35 Hrs (ii) Location Raichur , Karnataka

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


Fault had occurred during 220kV bus changeover at Raichur TPS. Unit#3, 400/220kV ICT’s and 220kV lines tripped on operation of back up protection.

(v) Generation Loss 150 MW (vi) Duration of interruption 7 Hrs to 96 Hrs (vii) Category GD 1

• The Grid Disturbance analysis as submitted by SRLDC is enclosed

herewith as Annexure X.

• The Grid Disturbance analysis as submitted by KPCL is enclosed

herewith as Annexure XI.


Deliberations

• KPCL informed that while transferring of loads from 220kV bus -1 to

220kV Bus-2, a fault had occurred at 11:35 hrs while closing of

bus-2 isolator of 220kV Lingasugar line-3 which in turn had resulted in

multiple outages at Raichur Thermal power station.

• The bus changeover was being done to carry out R&M works. The

220kV lines, ICT-1&2 and Unit #3 at Raichur had tripped on operation

of backup protection.

• 220kV Shahapur line-1, Sedam line-1&2, Raichur line-1&2 had been

hand tripped at Raichur end.

• KPCL also reported that there was outage of 220kV bus at Sedam &

Raichur sub stations.

• The forum requested KPCL to submit the Disturbance recorder/ Event

logger print of respective station to SRLDC/SRPC for further analysis.

• The Status of Bus-bar protection for 220 kV bus at Raichur TPS, the

Protections operated in 220kV Shahapur line-1, 220kV Sedam line-

1&2, 220kV Raichur line- 1&2 and the Reason for 220kV bus outage

at 220kV Sedam and Raichur substation may be sent latest by

19.07.2013.

Recommendations

Ø The forum requested KPCL to send the complete tripping analysis

report with the data requested above with the remedial measures

taken by them to prevent such outage/tripping of unit.

14. Logic checking of Critical Substations in the Southern Region approved in the SRPC meeting

• 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

ii. 400 kV Ramagundam

iii. 400 kV Kalpaka

iv. 400 kV Nelamangala

v. 400 kV Hoody


vi. 400 kV Kurnool

vii. 400 kV Almatti

viii. 220 kV Edamon

ix. 400 kV VTS

x. 400 kV Vemagiri

• It had been brought to the notice of the forum that Minimum 2 days required to completely check the Protection logic of the Substation and would be coordinated with the outage of lines / Station and would be coordinated with the OCC forum.

Deliberations

Member Secretary informed the forum that Central Power Research Institute

(CPRI), Bangalore had kindly agreed to carry out the Protection logic

checking of Substation for demonstration purpose.

• KPTCL suggested that 400 KV Nelamangala Substation be analyzed for this purpose.

15. Protection Audit of Substations in the Southern Region

It is informed that the Protection Audit of the following Substations had been carried out on 9 th and 10th July 2013.

(i) HVDC Kolar SS

(ii) HVDC Gazuwaka Back to Back SS

(iii) 400 KV Munirabad SS

(iv) 400 KV Kochi SS

(v) 400 KV Dichipally SS

Deliberations

• Member Secretary (I/c), SRPC requested SRTS I& II/PGCIL, APTRANSCO to address the observations /recommendations noticed during the protection Audit of the above substations.

Recommendations

The PCSC forum recommended PGCIL and APTRANSCO to inform the

forum in the 23rd PCSC regarding the remedial measures taken by them to

address the protection Audit Observation/Recommendations' noticed during

the protection audit.


16. Minor Trippings

The Minor trippings that had occurred in the Southern Region during the

months of June and July 2013 as submitted by SRLDC, POSOCO is attached

herewith as ANNEXURE XII.

17. Non-submission of Nomination for Protection Tripping Analysis team to be formed by SRPC in case of major tripping incidence in the southern region

• It is informed that as on 19.07.2013, the following utilities had not communicated the Grid Disturbance Analysis Expert team member (Main Member and Alternative Member) Nominations.

(i) APGENCO,

• APGENCO was requested to please communicate the Name and Mobile Numbers or the representative Team Members of the Protection System Expert Group to be formed at the earliest.

18. SPS FOR 400 KV KOLAR - HOSUR LINE • SRLDC proposed for SPS at 400 KV D/C Kolar Hosur Line.

• Tripping loads at Salem in the contingency of tripping of one line of 400

KV Bangalore-Salem or Hosur-Salem has already been commissioned

and is in service.

• If the Talcher-Kolar flow is more than 2000 MW and the S2 schedules

are more than 4500 MW, then the flows on the Kolar-Hosur lines are

around 560 MW each.

• In this particular scenario, in case of a contingency of KLR-HSR any

one of the circuit tripping the flow on the other circuit was likely to go

beyond 850 MW.

• Talcher-Kolar HVDC has an additional facility of run-back, wherein

power could be reduced to a new set-point with fast ramp.

• This feature could be used for addressing this particular contingency.

During N-1 condition the other circuit carried 982 MW.

• A study had been conducted by SRLDC to address this particular

contingency. As per the study results, a run-down of 500 MW in

Talcher-Kolar HVDC and initiating Trip Signal 2 only of Talcher-Kolar

SPS for S2 Constituents alone (445 MW load shedding in S2 area (TN


AND KL) the line flow on the remaining circuit could be restricted to

824 MW. The study result as furnished by SRLDC is attached as

Annexure XIII.

Deliberations

• SRLDC also informed that the schedules to states may not get affected

on account of the proposed SPS operation and the Commercial

settlement due to SPS operation would be settled under UI

Mechanism.

• APTRANSCO informed that the SPS proposal would be agreed

subject to commercial issues as approved by their Head Quarters.

• After discussions, the forum in principle agreed for the SPS for 400 KV

Kolar Hosur Line.

Recommendations

The PCSC forum recommended for the implementation of the proposed SPS

at the earliest.

19. Status of implementation of various SPS proposed in the southern region

Sl. No.

Name of the Scheme Details of the scheme

Implementing

Agency

22nd PCSC Deliberations Remarks

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 Under Process. Would be completed by 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 planned on 7th August 2013.

Postponed as per the request of APTRANSCO and TANTRANSCO

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

Status to be updated.


20. Status of implementation of various SPS proposed in the Andhra Pradesh periphery

Sl.No

Name of the Scheme

Details of the scheme Implementin

g Agency 22nd PCSC

Deliberations Remarks

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 Rest of the Scheme would be completed at the earliest.

Status -APTRANSCO/SRTS I , PGCIL

2 Chittur-Tiruvalum SPS

Tripping of 220kV Chittur-Tiruvalum S/C line in case of over loading of upstream lines of Andhra Pradesh Network. Proposed in 15th PCSC (18.07.2012)

APTRANSCO APTRANSCO informed the Scheme would be ready within July 2013.

APTRANSCO informed that implemented w.e.f 27/07/13

3 Sullurpet-Gummidipoondi SPS

Tripping of 220kV Sullurpet-Gummidipoondi S/C lines in case over loading of upstream transmission line of Andhra Pradesh Network. Proposed in 15th PCSC (18.07.2012).

APTRANSCO APTRANSCO informed the Scheme would be ready within July 2013.

APTRANSCO informed that implemented w.e.f 29/07/13

4 Nellore-Alma tti 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 SRTS I, PGCIL informe d the forum that the SPS scheme was Implemented w.e.f 23.05.2013

MEPL sent the confirmation.

21. Status of implementation of various SPS proposed in the Karnataka periphery

S.No

Name of the Scheme

Details of the scheme Implementing Agency

22nd PCSC Deliberations

Remarks

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

220 kV line CVTs are being replaced under R&M work. Once the PLCC equipments are restored the SPS will be implemented.

KPTCL was requested to submit the SPS Logic to the SRPC Secretariat. SPS would be implemented at any time –pending due to R&M works in the Somanahalli SS.


22. Status of implementation of various SPS proposed in the Tamilnadu periphery

S.No

Name of the Scheme

Details of the scheme Implementing

Agency 22nd PCSC

Deliberations Remarks

1 Thirunelveli SPS

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

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

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

2 Madurai SPS To avoid overloading of Madurai ICTs. TANTRANSCO TANTRANSCO informed that the scheme would be ready by end of August 2013.

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

23. Protection aspects of Renewables

SRLDC emphasized the importance of protection aspects for Wind Mills Generators. With increasing penetration of Renewables, such incidents involving large scale cascading outages of wind farms could become frequent. The brief of the protection aspects of Wind turbines as furnished by SRLDC is enclosed as Annexure XIV.

Deliberations

• SRLDC informed that the wind generators have a wide range of protection systems designed for making them more compatible with large grids. The Low Voltage Ride-Through (LVRT) capability is one amongst them.

• On 07-06-2013 at 10:47 hrs, there was an incident involving loss of about 1,300 MW of wind generation in Tamilnadu due to outage of 230/110kV Kayathar substation of TANTRANSCO.

• The loss of wind generation had led to sudden dip in regional grid frequency from 50.05 to 48.83 Hz.

• Dip in frequency had also led to operation of under frequency load shedding scheme in Southern Region.

• SRPC informed the forum that it was learnt that very few of the existing 6000-8000 MW wind turbines in TamilNadu were equipped with LVRT Technology.

• Forum also noted that the capacitor banks were not being switched off even after wind season, resulting in high voltage in the vicinity of Thirunelveli.

• ED, SRLDC also proposed a meeting with wind generators and SLDCs for addressing the Wind Generator Protection issues.


Recommendations

Ø The PCSC forum recommended for the special meeting of Wind

Generators and SLDCs for discussing the protection aspects of Wind

Generators.

24. Implementation of Islanding schemes proposed in the southern region

• The enquiry committee report of the Grid Disturbances in NEW Grid on 30th & 31st July 2012, in its recommendation had directed CEA, RPCs, POWERGRID, STUs, SLDCs & Generators to design islanding schemes based on frequency sensing relays.

• Ministry of Power vide Order dated 13.12.2012 had constituted a Task Force on Power System Analysis under Contingencies. The Task force meetings were held to discuss the various Protection aspects of Indian Power System. The Task Force had given guidelines on formation of Islanding Schemes in the Southern Region. All the islanding scheme (existing / proposed) in the Southern Region thus needed to be reviewed according to the Task Force guidelines.

• The following Islanding Schemes had been proposed in the Southern Region:

1) Modified S1-S2 Islanding Scheme.

2) Ramagundam – Hyderabad Islanding Scheme.

3) Chennai Islanding Scheme-Vallur NTECL, NCTPS, GMR, MAPS

4) Kudankulam, Tuticorin, Sabarigiri, Trivandrum Islanding Scheme.

5) Kundah, Coimbatore, Erode, Neyveli, Mettur Islanding Scheme.

• The Islanding Schemes/settings would be modified in future according to the system requirements, if any, including addition of new units etc.

• The Procurement /installation of UFRs for the islanding schemes would be carried out at their end.

• The Communication regarding this was addressed to the Constituents vide SRPC letter dated 20.05.2013 and the details of Feeders involved in Islanding scheme was circulated in the 21st PCSC Minutes.

• APTRANSCO, NTPC and PGCIL had sent the confirmation regarding revision of Ramagundam Hyderabad Islanding Scheme frequency to 47.9 Hz w.e.f 12:00 Hrs of 1st July 2013.


Deliberations

• The Stage I of the Islanding scheme as agreed had to be implemented by end of August 2013.

• Member Secretary (I/c) requested all the constituents to be ready with the Under Frequency Relays for implementation of the Islanding Schemes in the Southern Region.

• TANTRANSCO informed that they had floated the tenders for the procurement of relays for implementation of the scheme.

Recommendations

Ø All the constituents were requested to update the progress made in

the implementation of the islanding schemes latest by 23.08.2013.

TANTRANSCO Vide Lr No CE/ P&C / SE /D / EPC Iv/ AEE3/

F.SRPC/ D.72/ 13 dt 07.08.2013 (Annexure XV) has informed that

a total of 9 relays were required for implementing the Islanding

Scheme.

Ø TANTRANSCO informed that they were gearing up to implement

the Modified S1-S2 (Stage-I) islanding scheme by the end of

August 2013.

Ø PGCIL, SRT-II was requested to install the requisite UFRs from

their end to implement the Stage-I (modified S1-S2) Islanding

scheme by end of August 2013.

25. Status of provision of Carrier aided tripping protection and provision of Single phase Auto-reclosing in 220 kV and above lines in SR

• In the earlier PCSC meetings, it was agreed to have Single Phase Auto-Reclosing scheme on all lines emanating from all major generating stations including nuclear stations and on all 220 kV and above rated lines. The PCSC forum recommended that all the constituents to have carrier aided tripping for all the 220 KV and above rated lines. The forum also recommended that all the constituents to have an independent Bus Bar protection scheme to protect their transmission system elements.

• The following utilities were requested to submit the data in the prescribed format

(1) APGENCO (2) NPCIL-MAPS (3) Puducherry


26. Status of provision of Bus Bar protection and LBB protection in 220 kV and above substations of SR

• In 16th PCC meeting, it had been requested to send the updated status of provision of implementation of Bus Bar Protection and LBB Protection in 220 KV and above Substations of SR.

• The following utilities were requested to submit the data in the requisite format.

(1) APGENCO (2) NPCIL-MAPS (3) Puducherry

27. The issue of increasing AUFR relief & implementation of df/dt settings in SR The Quantum of Relief for AUFR relay settings in the region as follows.

(Figures in MW) df/dt settings in SR

Group-1: 49.3 Hz 0.3 Hz/sec fall of frequency

Group-2: 49.5 Hz 0.2 Hz/sec

• All the states agreed in principle to have three stages of UFR settings at 49.2 Hz, 49.0 Hz and 48.8 Hz .The existing quantum to be retained.

• The stages would be revised as per the above revised settings, when the SR grid is synchronized with NEW Grid.

• Overlapping Constraints were highlighted by the constituents. However SRPC and SRLDC brought to kind attention that the grouping of loads and segregation etc was regulatory requirement.

• Inadequate relief and load generation imbalance during the 7th June incident would be investigated by each of the states. Report would be furnished and adequate steps would be taken to ensure that desired relief is obtained in future.

Constituents AP KAR KER TN PUDU

Stage – I @ 49.0 Hz 887 718 215 591(842) 18

Stage – II @ 48.8 Hz 1256 895 300 1024(1071) 29

Stage – III @48.6 Hz 1424 732

342

1005(1207) 34

Total (implemented) 3567 2345 857 2620(3120)* 81

TOTAL 9970


Deliberations

• Member Secretary (I/c), SRPC informed the forum that the Second meeting of National Power Committee had been held on 16th July 2013 at New Delhi. The matter regarding quantum of loads under AUFLS was discussed in the Meeting.

• In the NPC meeting it was 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.

• The quantum of loads at each stage had been calculated as per the Zhalte Committee Report.

• In view of the decision taken in the 2nd meeting NPC held on 16.07.2013 all the Regions to have 4 stages of AUFLS, Southern Region would also need to carry out necessary changes in the relay settings so as to implement the same.

28. Submission of 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 us at the earliest by Email to the following Email IDs.

• The forum requested that the Dynamic study data of Machines less than 50 MW also be sent to SRPC Secretariat for Analysis.

29. Providing Synchronizing facility at key stations for Black start restoration

The status of installation of synchronizing equipment in the following key

stations may be informed to the PCSC forum.

Sl. No. Sync. facility requirement Status

1 Hubli To be provided during R & M works.


• The PCSC forum requested KPTCL to provide synchronizing facility in

Hubli S/S latest by January 2014.

30. Requirement of Under Voltage relays (UVR) for SR

SRLDC vide Lr No SRLDC/SRC&S/ Prot/2012 / 1110 dt.15.03.2013 (Item No

7) had proposed for the provision of under voltage relays in the following

locations in the Southern Region:

State Under Voltage relay required at 220kV substations

Karnataka (Bangalore area Mysore area)

Bidadi, Somanahalli, Subramnyapura, HSR layout Naganathpura, Hoody, Hebbal, Whitefield, HAL, Nelamangala, Peenya, D.B.Pura, Antharsanahally, Dobspet, Basthipura,Hootagalli, Tubinakere, A Station, EDC compound, Kunigal and Kadakola

Andhra Pradesh (Chittur area)

Chittoor, Palamaneru, Kalkiri, Renigunta, Kodur, Rajampet

Tamilnadu (Chennai area)

Siruseri, KITS Park, S.P.Koil, Sriperumbudur, Gummidipoondi, Koratur, Koyambedu, Kadaperi, Mamambankam ,Taramani, Almatti, Manali, Oragadam, Kilpauk, Thondiarpet, Mylapore

Kerala

Kalamassery, Palakkad, Madakkathara, Areakode, Kaniyampet, Shornur, Malapparamba, Vadakara, Kanjirode, Talaparamba, Kasarkode, Phothenkode, Edappon, Kundara

• KSEB had informed that they had identified the nodes for installation of UVR and they were waiting for the concurrence of SRPC and SRLDC in this regard.

• KPTCL had informed that other methods of containing Under Voltage like putting capacitor banks on, adding additional lines etc. were taken to improve the voltage.

• KPTCL had informed that in Bangalore metro 220 KV underground cables were being laid which would help improve voltage profile in Bangalore area.

• KPTCL had also informed that the study of reactive power management is being conducted by PRDC which expected to complete soon.

• APTRANSCO had informed that the under voltage relay required were based on earlier studies. However in the present scenario APTRANSCO was not facing any under voltage issues rather there are High voltage nodes.

• ED, SRLDC informed that States were exclusively depending on generators for VAR compensation like KPTCL depending on UPCL,


APTRANSCO on RTPS and TANTRANSCO on NCTPS, NTECL. In the event of unit outage of these generating stations, the Voltages of Bangalore, Chennai and Chittor areas would get affected.

• ED, SRLDC insisted for providing UVR in the above specified nodes as constituents had to ensure voltages within IEGC range in different scenarios.

• TANTRANSCO informed the forum that around 5000 MVAR capacitor is getting added in TNEB system. In addition around 2400 MW Generation would be added to TamilNadu Grid and thus conditions of Under Voltage would not arise.

• ED, SRLDC informed the forum that the provision of Under Voltage Relays had been deliberated in the PCSC meetings (from 16th PCSC: 06.11.2012 to till date) for the for past six months.

• ED, SRLDC also informed the forum that SRLDC, POSOCO would be constrained to approach Hon’ble CERC in the event there was no improvement in the situation.

Ø Constituents were requested to install the UVR at least in a phased manner in the above specified nodes. Progress in this regard may be reported to the PCSC forum in the 23rd meeting of PCSC.

31. Validation of lines: Loading on Transmission System based on the CEA "Manual On Transmission Planning Criteria"

• SRPC vide Lr No SRPC/SE-II/16 PCC/2012/10646-10668 dated 31.10.2012 had circulated the loading of Transmission system based on the CEA manual on transmission planning criteria for validation. It was requested that the data may be perused and the following action in this regard:

(i) Validation of data pertaining to the respective system.

(ii) Missing data may be furnished so that the entire document may become validated one.

(iii) Wherever Zone 3 Settings or Over current settings interfere with the line loadability.

Ø Puducherry was requested to send the validated data at the earliest to the PCSC forum.


32. Implementation of recommendations of Grid Disturbance enquiry committee

(a) Protection Audit Compliance

In Phase I Audit, 194 Substations were covered and Audit Observations and Remarks were sent to the constituents for compliance.

The status of compliance (All the Constituents):

The corrective action taken by the constituents to attend to the observations / Remarks made during Protection Audit may please be intimated.

(b) Healthiness of Batteries

Healthiness of Batteries Installed at Substations (to provide Backup supply to the Relays, RTUs and Communication Equipments) may be updated regularly since the same has to be communicated to CEA.

• All the constituents were requested to submit the healthiness of batteries on monthly basis (i.e. on 7th day of the month).

• MAPS-NPCIL, and Puducherry were yet start reporting the status of healthiness of Batteries to the SRPC Secretariat.

33. Over Voltage stage-1 setting for parallel transmission lines

• The issue of Over voltage Grading was discussed in the OCC forum and it was decided to have Voltage Grading with respect to Voltage also.

• In the meeting it was decided to set the non Critical lines at 109% to avoid picking up all the relays at 110%.

• The remaining Lines would be time graded with the time grading from 5 to 10 seconds delay.

Node wise /Lines wise issues raised by the constituents were discussed and considered for implementation.


34. Submission of equipment failure data of 220 kV and above substations in the southern region to CEA

• It was informed that under section 73, clause (1) of Indian Electricity Act 2003 a standing committee (comprising of experts from various organizations) had been formed to investigate the failure of equipment at 220 KV and above Sub stations .

• It was also informed that the terms of reference of the Committee as follows

(a) Investigate the failure of Sub Station equipment in Service and

(b) To recommend remedial measures to avert recurrences of such failures in future.

• It was informed that every incident of substation equipment failure needs to be immediately reported to the Chair person of the Standing Committee by a designated officer of the concerned organization (i.e. Protection In charge).

• Member Secretary (I/c), SRPC requested that the constituents to submit the Equipment Failure Report in the prescribed format to the following Address with a copy to SRPC.

“Chief Engineer (SETD), CEA, Sewa Bhawan, R.K.Puram, New Delhi - 110 066”

35. Consolidated List of data to be sent to SRPC Protection Wing.

The consolidated list of data/document to be sent to SRPC in enclosed

herewith as Annexure XVI .The format to be sent is enclosed herewith as

Annexure III and XVII to XXI.

36. Date & Venue of the next Meeting

The 23rd PCSC meeting would be held on 27.08.2013 (Tuesday).

Member Secretary i/c thanked all the participants for their contribution to the

meeting.

*****

Documents

SOUTHERN REGIONAL POWER COMMITTEE - Karnataka · held on 31st July 2013 in the Conference Hall of Southern Regional Power Committee, Bangalore. The list of participants for the PCSC