documents through DMNS application. The updated version of PSCT software, PSCT manual, PSCT bus breaker model (PSCT case file) for SR region and excel sheet containing statewise element

Minutes of the 85th

Meeting of PCSC held on 31st July, 2019 Page 1

SOUTHERN REGIONAL POWER COMMITTEE BENGALURU

Minutes of the 85th Meeting of Protection Coordination Sub-Committee (PCSC – 85) of SRPC held on 31st July, 2019

1. Introduction

The 85th meeting of Protection Coordination Sub-Committee (PCSC-85) of SRPC was held on 31st July, 2019 at SRPC Secretariat, Bengaluru. The list of participants is enclosed at Annexure-I. MS (I/c) SRPC welcomed Members and Participants to the meeting and briefed them on the following points: Apprised PCSC forum that Protection Audit of 400/220/132kV Jamalamadugu SS of APTRANSCO was completed successfully during 17-18th July 2019.

The protection Management System (PMS) project is in the final phase of completion and requested all constituents to extend all support in this regard.

Informed constituents that Nominations have been obtained from majority constituents for Conduction of Protection Audit of various 220 kV & above Stations in Southern Region. He requested all constituents to suggest modifications in Protection Audit formats (used for Protection Audit) to modify the same at par with present practices.

2. Confirmation of Minutes of 84th PCSC meeting held on 26th - 27th July 2019

The minutes of the 84th meeting of PCSC were circulated vide SRPC letter No. SRPC/SE-III/ PCSC-84/ 2019/4335- 4371 dated 11.07.2019. No comments had been received from any of the Constituents. The minutes of the 84th meeting of PCSC were confirmed.

3. Details of Grid Disturbances (GD’s), Grid Incidents (GI’s), and Line Trippings

due to Auto- Reclose (A/R) failure/ non-operation & PLCC mal-operation

The trippings due to GD’s, GI’s, A/R failure/ non-operation, and PLCC mal-operation that had occurred during May, 2019 – July, 2019 were discussed in the Meeting. The deliberations and recommendations of the PCSC forum are enclosed at Annexure–II for needful action please. The details of the tripping events including relevant PMU plots presented by SRLDC in the meeting are also enclosed at Annexure-III for kind reference.

4. Status of implementation of pending PCSC Recommendations (P-REC)

The status of implementation of pending PCSC recommendations was discussed in the meeting. The updated status of the same as on 19.08.2019 is enclosed at Annexure–IV. The Constituents were asked to take steps to comply with the same, and requested to submit the status of their compliance latest by 28.08.2019.

5. Remedial measures/ Action taken for the tripping incidents of the transmission

elements under forced outage (PRM)

The tripping incidents of the transmission elements under forced outage for which the constituents have to furnish remedial measures taken, were circulated via mail dated 01.08.2019 (Annexure-V). The Constituents were requested to take appropriate action and

Minutes of the 85th


furnish specific remedial measures/action taken covering one or the other items from the following indicative list in time so as to forward the same to Central Electricity Authority: Brief details of line patrolling carried out (with tower location) Brief details of RoW maintenance (by proper Tree-cutting) resorted to De-capped insulators replacement DC earth fault removal PLCC cards replacement Relay settings modification Steps taken to put A/R or CB into service after they have been locked-out Faulty equipment replacement Reference to OEM in case of equipment failure Brief Details of tests carried out to ascertain the healthiness of various equipment (Power Transformer/ Reactors/ Surge Arrestors/ Circuit Breakers/ CT's/ PT's/CVT's) like Insulation Resistance (IR) test, Winding Resistance test, Capacitance test, Tan delta test, DGA test, Leakage current test, CRM/ DCRM test, etc. Any other appropriate remedial measure It was observed that many utilities default furnishing of remedial measures for tripping. It is requested to take prompt and definite measures and ensure that Remedial measures are intimated on regular basis. 6. Certificate on Healthiness of Batteries

As per MoP/ CEA direction given in pursuant to recommendations of the Enquiry Committee (NEW Grid Disturbance on 30th & 31st July, 2012), RPC’s are required to obtain from their respective Constituents a monthly certificate for healthiness of batteries installed at 220 KV & above voltage level Substations (for power supply to Relays, RTUs and PLCC equipment) and furnish the same to CEA/ MoP. With reference to above, the Constituents were requested to submit the certificate on healthiness of batteries on monthly basis (i.e. status for a month shall be sent by the 7th day of the following month) to SRPC as per the format given below:

Sl. No.

Station Application Battery Battery Charger Remarks

Station Name

Code

Type

(PS/ SS)

Protection/

Communication

Details

Status (Healthy/ Unhealthy)

Details

Status (Healthy/ Unhealthy)

Brief Details of unhealthy battery banks and/ or DC leakage along with proposed time-lines for rectifying the same shall be mentioned.

1 Station-A

Protection (Bank-1)

Protection (Bank-2)

Communication (Bank-1)

Communication (Bank-2)

2 Station-B

…

… … …

Note: 1. Code is the short name of the Station 2. PS – Power Station; SS – Substation

The sought status for the month of June, 2019 had been received from all constituents.

Minutes of the 85th


7. General Guidelines regarding Line Differential Protection for transmission

lines

The draft protection standards prepared by national Reliability Council for electricity mentions reliability criterions for transmission line having voltages at 220kV and above as:

“High speed Duplicated Main Protection (Main-I and Main-II) shall be provided and at least one of them being carrier aided non-switched four zone distance protection. The other protection may be a phase segregated current differential (this may require digital communication) or a carrier aided non-switched distance protection. Wherever Optical Ground Wire (OPGW) or separate optic fibre laid for the Communication is available, Main-I and Main-II protection shall be the line differential protection with distance protection as backup (built-in Main relay or standalone). For very short line (less than 10 km), line differential protection with distance protection as backup (built-in Main relay or standalone) shall be provided mandatorily as Main-I and Main-II). “

The general guidelines to be followed for Line Differential Protection was discussed in the meeting. During the discussion, SR constituents had brought out the following facts with regard to Line Protection. Transmission lines which are the most vital link in power transmission run through open atmosphere and the probability of occurring faults in them is very high compared to any other power system equipment. Operation of a standard Protection system in the event of fault is envisaged not only to selectively isolate the faulty element but also to maintain reliability of supply in the system. The capability of zone- segregated distance protection in achieving the same is a well-established fact and hence is being used in protection of transmission lines.

But when the length of protected transmission line is short (less than 10km) due to the limitations imposed in accurate setting of Zone -1 (primary zone of distance protection) by R/X value of relay, distance protection is seen to overreach for a fault on adjacent transmission line and cause unwarranted tripping. Line differential protection devoid of such overreach issues is important under such circumstances. Wherever Line differential protection is to be used as main protection (Main-1 and Main-II), distance protection has to be invariably provided to cater to function as back up protection for adjacent transmission line.

SR constituents were of the opinion that Line differential protection is required as Main protection only in case of short length of transmission line. Also in radial single circuit line less than 10km, distance protection will function reliably without any overreach. Line differential protection not only mandates laying of separate fibre optic, but is also much expensive compared to distance protection.

Hence, the guidelines for Line Differential Protection for transmission lines having voltages at 220kV and above recommended by PCSC-85 and communicated to NPC vide SRPC letter dated 01.08.2019 are:

“High speed Duplicated Main Protection (Main-I and Main-II) shall be provided using carrier aided non-switched four zone distance protection.

For very short line (10 km or shorter), except radial single circuit line, phase segregated current differential protection (this may require digital communication) with distance protection as backup (built-in Main relay or standalone) shall be provided mandatorily in Main-I and Main-II.

Wherever Optical Ground Wire (OPGW) or separate optic fibre laid for the Communication is available, Main-I and Main-II protection may be line differential protection with distance

Minutes of the 85th


protection as backup (built in Main relay or standalone).

Whenever differential protection is provided it should be provided both in Main-I and Main-II otherwise it will not serve the intended purpose.

However, in all Critical links recommended by PCSC forum of RPC (to be decided on case to case basis), utility shall provide line differential protection irrespective of length of line.”

For transmission lines having voltages at 132 kV and below, the general protection guidelines suggested by National Reliability Council for electricity are:

“There should be at least one carrier aided non-switched four zone distance protection scheme. In addition to this, another non-switched/switched distance scheme or directional over current and earth fault relays should be provided as back up.”

Providing Line Differential Protection for these lines shall be at the discretion of utility. 8. Status regarding Protection Management System (PMS) project

The Protection Management System Project (PMS) for Southern Region implemented by M/s PRDC is nearing completion. During the review meeting held on 24.06.2019, PRDC demonstrated the following features of PSCT. Load flow analysis, Fault simulation of Renewable generators modelled using the actual

field data. Unified Power Flow controller block developed for use in PSCT modelling was

demonstrated on IEEE 6 bus system along-with the voltage and Power flow control capability of UPFCs on the test system.

Functioning of 3 winding phase shifting transformer modelled as available at KTPS station of TSGENCO.

Improvement done in MVAR compensation functionality of PSCT. Provision for globally changing voltage and location of MVAR compensation has been

made, accordingly the software calculates the amount of compensation required. Transient stability analysis of Renewable generators and plotting of related curves.

Apart from the above PRDC also submitted the Protection SLDs of all Substations visited during 2nd Phase of data collection in January 2019. The same has been circulated among constituents for verification. PRDC also submitted statewise excel sheet containing element information of all elements modelled in SR MDB case vide mail dated 26.06.2019. As decided by Monitoring committee, letter regarding “Resolution of Issues pertaining to PMS

Project under Milestone-5 and Milestone-9” was addressed to PRDC. PRDC had submitted their

action plan regarding pending activities of Milestone 5, 7, 9 & 10 vide reply dated 4th

July 2019.

Further SRPC had sought time extension for PMS project from PSDF vide SRPC letter dated 22.07.2019. The constituents were requested to inform the network updates along-with the supporting

documents through DMNS application. The updated version of PSCT software, PSCT manual, PSCT bus breaker model (PSCT case file) for SR region and excel sheet containing statewise element details have been uploaded in the ftp link provided by PRDC to SR constituents. Constituents were requested to make use of the same by downloading from the ftp link.

9. Over Voltage (OVR) Grading

New Over Voltage Relay (OVR) Gradings for 400 kV and 765 kV Transmission Lines of Southern

Minutes of the 85th


Region had been issued vide SRPC letter No. SRPC/SE-III/OVR/2019/4074-4107 dated 03.07.2019. New gradings had been issued only for lines with configuration changes, for remaining lines previous OVR gradings shall prevail. Confirmation with respect to implementation of the same have been received from following utilities:

APGENCO (Thermal & Hydel), NTPC (RMGDM), CEPL, NTPL, APTRANSCO and KPTCL.

All the remaining constituents were requested to take steps to implement the new OVR gradings provided, with immediate effect and inform confirmation in this regard urgently.

APTRANSCO and KPTCL informed that configuration changes in their network. SRPC shall be providing revised OVR gradings for the substations with configuration changes.

10. Maintenance & Support (AMC) renewal of PSSE Licenses

In 2012, POWERGRID had coordinated one-time capacity building exercise for various stakeholders, under which 35 No. of PSSE Licenses were distributed among SR utilities. The maintenance and support for supplied licenses was for a period of 6 years, which had ended on 30th November 2018. The communication regarding renewal of the maintenance and support for the above Licenses received from M/s Seimens and Budgetary Offer had been communicated to constituents vide mail dated 12.06.2019 and 14.06.2019 respectively.

Meanwhile SRLDC had informed that the matter is being pursued by SRLDC in association with NLDC. Hence the matter would be further coordinated by SRLDC. 11. Nominations of Nodal Officers for Conduction of Protection Audit of various 220

kV & above Stations in Southern Region

As per the discussions of PCSC-80 conduction of protection audit of various 220 kV & above Stations in Southern Region was approved in 35th SRPC meeting. Nominations in this regard were sought from all Utilities vide SRPC letter No. SRPC/SE-III/ PA/ 2019/3589-3618 dated 19.06.2019. Based on consolidation of responses received in this regard nominations have been received from all constituents except NLCIL. NLCIL was requested to urgently furnish the nomination for charting the schedule for audit.

12. Instances of SPS Operation

Based on the information furnished by SRLDC, it is informed that the following SPS operations took place in SR during June 2019:

Sl. No. Date

Time, hrs

Reason Actual Load Relief obatined, MW

TN KA TS

AP KL

Total

1

05.06.2019

18:53

Talcher- Kolar SPS: HVDC Talcher-Kolar Pole-1 tripped. SPS trip signal-1 operated since power loss was more than 500MW but less than 1000MW.

200 35

0 -

15

3 -

703

2 05.06.201

9 19:01

Talcher- Kolar SPS: HVDC Talcher - Kolar Pole-2 tripped. SPS trip signal-1 did not operate since power loss after pole tripping was less than

-- -- --

-- --

--

Minutes of the 85th


500MW.

3 08.06.2019

12:10

Talcher- Kolar SPS: HVDC Talcher-Kolar Pole-1 tripped. SPS Trip Signal-1 operated since power loss was more than 500 MW and less than 1000 MW.

276 35

0 -

21

9 -

845

4 12.06.201

9 12:24

Talcher- Kolar SPS: HVDC talcher-Kolar Pole-2 tripped. Since power loss immediately after tripping of pole-2 was around 400 MW, hence SPS did not operate (power loss <500MW).

-- -- --

-- --

--

5

04.06.2019 11:36

SPS at Kudankulam Nuclear Power Station Unit#1: KKNPP Unit#1 tripped. SPS operated at KKNPP. However ,SPS signal not transmitted towards loads

-- -- --

-- --

--

13. Network Configuration Changes

The following Network configuration changes occurred in the month of June 2019.

Erection of 220 kV D/C line from 400 kV SS Sattenapally to 220 kV SS Guntur in Guntur District (95.59 Ckm) was commissioned on 29.06.2019 by APTRANSCO.

400 kV/220 kV Bus Reactor of Jammalamadugu SS in Kadapa District (80 MVAR) was commissioned on 03.06.2019 by APTRANSCO.

220 kV line on Multi Circuit towers for making LILO of Both circuits of existing 220 kV Waddekothapalli I&II Bhongir DC line at 400/220 kv SS Janagaon (104.06 Ckm) was commissioned on 12.06.2019 by TSTRANSCO.

400 kV Quad Moose DC line from Julurupadu I&II to Janagaon SS (174.72 Ckm) was commissioned on 26.06.2019 by TSTRANSCO.

220 kV DC line from proposed 220 kV Rampur I & II SS to proposed 220/11 kV Rajeshwarrao Peta Substation (72 Ckm) was commissioned on 28.06.2019 by TSTRANSCO.

220/11 kV Rajeshwarrao peta I & II SS (120 MVA) in Jagtiyal District was commissioned on 28.06.2019 by TSTRANSCO.

8th 220/11 Kv, 50 MVA PTR at Medigadda SS in Jayashankar Bhoopalpally District (existing 7x50 MVA) was commissioned on 17.06.2019 by TSTRANSCO.

6th & 7th 220/11 kV, 50 MVA PTRs (2 x 50 MVA) at Annararam SS in Peddapalli District (Existing 5x50 MVA) was commissioned on 18.06.2019 by TSTRANSCO.

2x50 + 1x80 MVA, 220/11 kV PTRs at Bheemghanpur SS in Jayashankar Bhoopalpally district (existing 1x31.5+2x50 MVA) was commissioned on 07.06.2019 by TSTRANSCO.

14. Date and Venue of Next PCSC Meeting

The date of 86th meeting of PCSC will be intimated in Agenda for PCSC-86.

*****

Annexure-I

Page 1 of 6

Annexure-I

Page 2 of 6

Annexure-I

Page 3 of 6

Annexure-I

Page 4 of 6

Annexure-I

Page 5 of 6

Annexure-I

Page 6 of 6

Grid Occurrences discussed in the 85thMeeting of PCSC scheduled held on 31st July, 2019 1/52

Grid Occurrences - 85

I. Details of Grid Disturbances:

Sl. No.

Details of Event Date &Time Reason Remarks Category

1

Complete outage of 220kV 220/110kV Palakkad Substation of KSEB

04-06-2019 at 14:02hrs

Testing of Bus Coupler CT was being carried out during which LBB trip got initiated and resulting in tripping of Bus-2. This resulted in the tripping all the connected elements at 220kV Palakkad Bus-2 leading to complete loss of supply

Load loss – 268 MW

GD-1

SLD: The SLD of 220/ 110 kV Palakkad SS of KSEBL is attached at the end.

Bus configuration and arrangement: Double Bus with Bus coupler Arrangement

Antecedent conditions: Bus - 1 was in dead conditions Bus -2 connected elements:220kV Palakkad – Palakkad PG line-1, 220kV 220kV Palakkad –

Palakkad PG line-2, 220kV Palakkad – Palakkad PG line-3, 220kV Madakathara – Palakkad line, 220/ 110 kV 200MVA Transformer 1, 220/ 110 kV 200MVA Transformer 2, 220/ 110 kV 200MVA Transformer 3.

Bus coupler was in open condition.

Tripping of 220kV Palakkad – Palakkad PG line-1,2 & 3: Palakkad (KSEBL) end:

As per FIR/ DR/ EL/ TR line tripped at 08:32:51.686 hr. on operation of LBB protection of Bus-2. Palakkad PG (PGCIL-Sr-2) end:

As per FIR/ TR line did not trip at Palakkad PG end.

220kV Palakkad PG

220kV Palakkad

110kV Palakkad

220kV Madakathara

Connectivity diagram of 220/ 110kV Palakkad SS of KSEBL

Annexure-II


Tripping of 220kV Palakkad – Madakkathara line : Palakkad (KSEBL) end:

As per FIR/ DR/ EL/ TR line tripped at 08:32:51.686 hr. on operation of LBB protection of Bus-2. Madakathara (KSEBL) end:

As per FIR/ TR line did not trip at Palakkad PG end. Tripping of 220/ 110kV Palakkad SS:

As per FIR/ DR/ EL/ TR 220kV Bus-2 tripped at 08:32:51.686 hr. on operation of Bus-2 LBB protection. The operation of Bus-2 LBB tripped all elements connected to Bus-2 ( i.e, 220kV Palakkad – Palakkad PG line-1, 220kV Palakkad – Palakkad PG line-2, 220kV Palakkad – Palakkad PG line-3, 220kV Madakathara – Palakkad line, 220/ 110 kV 200MVA Transformer 1, 220/ 110 kV 200MVA Transformer 2, 220/ 110 kV 200MVA Transformer 3 ). Total load loss reported during the event is 268MW.

KSEBL informed that The high impedance BBP at 220kV Palakkad substation was replaced with new low impedance GE make numerical bus bar protection and commissioned on 30.05.2019. At the time of commissioning the 220 KV Bus coupler was not in service. On 04.06.2019, relay team carried out pre commissioning testing on bus coupler CT after putting BBP selector switch to out of service.

While carrying out CT secondary injection, the relay team had injected current in O/C and E/F core first. This had led to operation of earth fault protection and master trip relay in bus coupler panel. Trip relay operation triggered LBB initiation in numerical bus bar protection. When relay team injected current in CT core connected to bus bar relay without resetting master trip relay, LBB trip was initiated. As all element were connected to same bus, all were tripped.

Deliberations:

In the antecedent condition, 220kV Bus-1 at Palakkad SS was under shutdown, Buscoupler was in open condition and all elements were connected to 220kV Bus-2. On 04.06.2019, relay team of KSEBL were carrying out pre commissioning testing on bus coupler CT after putting BBP selector switch to out of service.

Initially the relay team had injected current in O/C and E/F core of Bus coupler CT. This had led to operation of earth fault protection and master trip relay in bus coupler panel. Trip relay operation triggered LBB initiation in numerical bus bar protection. The relay then reset only the trip relay but not the lockout relay. Hence LBB initiation was high. Subsequently relay team injected current in CT core connected to bus bar relay. Presence of current alongwith LBB initiation led to operation of LBB protection for Bus-2 and tripped all elements connected to Bus-2. Total load loss reported during the event was 268MW.

Remedial Measures Taken: KSEBL vide mail dated 29.07.2019 informed that: Warning stickers were provided and other precautionary steps were taken to avoid this in

future. GPS connection was corrected and found OK.

Annexure-II


2

Complete outage of 220kV Pothenkode Substation of KSEB

04-07-2019 at 01:18 hrs

Triggering incident was failure of suspension insulator of 220kV Pothenkode – Trivendrum ckt-2. Bus bar protection of Bus-1 and Bus -2 operated resulting in tripping of all connected elements.


GD-1

SLD: The SLD of 220/ 110 kV Pothencode SS of KSEBL is attached at the end.

Bus configuration and arrangement: Double Bus with Bus coupler arrangement [ Bus 1 extension also available so there are 3 buses]

Antecedent conditions: Bus-1 connected elements: 220kV Pothencode – Edamon line 1, 220kV Pothencode –

Trivandrum line – 1 & 3, 220/ 110kV 200MVA Transformer 1& 3. Bus-2 connected elements:220kV Pothencode – New Kattakada line 1 & 2, 220kV

Pothencode – Edamon line 2, 220kV Pothencode – Trivandrum line – 2 & 4, 220/ 110kV 200MVA Transformer 2

Bus coupler in closed condition

Tripping of 220kV Pothencode Trivandrum Line -1,2& 4: Pothencode (KSEBL) end:

As per FIR/ DR/ EL/ TR line tripped at 01:17:29.751 hr. on operation of Bus Bar Protection. Trivandrum (PGCIL-SR-2) end:

As per FIR/ EL/ TR line tripped at 01:17 hr. on receipt of DT from remote end.

KSEBL informed that suspension insulators connecting fly bus and 220 kV bus isolator unit totally exploded leaving the conductor hanging freely from fly bus assembly

Connectivity diagram of 220/ 110kV Pothencode SS of KSEBL

220kV Pothencode

110kV Pothencode

220kV Trivandrum

220kV New Kattakada

220kV Edamon

Annexure-II


Tripping of 220/ 110kV Pothencode SS:

As per FIR/ DR/ EL/ TR all connected elements of 220kV/ 110kV Pothencode SS tripped at 01:17:29.751 hr. on operation of Bus Bar Protection.

KSEBL informed vide mail dated 29.07.2019 that Busbar protection was operated in 220 kV Substation, Pothencode on 04-07-2019 at 01.17 Hrs. This is due to failure of B phase string of fly bus of 220 kV TVPC #2 feeder. Busbar protection on Zone 2 operated. All feeders and transformers connected to Zone B (Bus2) tripped immediately. Trip in Zone B (Bus2) was found in order. Differential current in Central unit was vanished by 55ms.

All feeders and transformers connected to Zone A(Bus 1) were tripped just after Zone2 except 200MVA transformer#3. Internal trips were initiated after 20ms (EMPC1, PGCIL1), 50ms(PGCIL3) and 73ms(Transformer 1&3). The reason of these trippings could not be identified. Bus coupler current was found very low by 55ms.

Breaker failure initiated in both Zone A and Zone B simultaneously. Simultaneous occurrence of breaker failure in both buses is also to be investigated. The currents in Bus coupler became low value after 55ms. Therefore, there is no reason for breaker failure. GPS connectivity was found lost in the relay due to fault in GPS card.

Therefore, detailed study is required for finding reasons and for rectifying the issues stated above.

Deliberations:

In the antecedent condition both Bus 1 & 2 were in service and buscoupler was in closed condition.

The triggering incidence for complete outage of 220/ 110kV pothencode SS was failure of suspension insulator (connecting to fly bus) of 220kV Pothenkode – Trivendrum ckt-2. Busbar protection for Bus-2 (Zone-2) operated and tripped all feeders and transformers connected to Zone B (Bus2) immediately. Operation of BBP for bus-2 is in order.

But 90msec after tripping of Bus-2, BBP for Bus-1 (Zone-A) also operated tripping all elements except 220/ 110kV transformer -1, (which was later handtripped) connected to Bus-1. Operation of BBP for Bus-1 is not in order.

KSEBL informed that on inspection it was found that Buscoupler current was very low after 55mec to tripping of Bus-2 hence, operation of BBP for Bus-1 needs further detailed inspection. Also Breaker failure was initiated simultaneously in both Zone A and Zone B and needs further investigation.

PCSC forum suggested checking of DC leakages in the substation and DC- AC mixing which might have led to tripping of Bus-1.

Remedial Measures Taken: KSEBL vide mail dated 29.07.2019 informed that:

Non tripping of Transformer 3 was rectified during the time of restoration. Steps have been taken to replace faulty GPS card in the relay to get GPS connectivity. Detailed testing of busbar system in Pothencode 220kV SS is planned to carry out in the

month of August to study the reasons for extended trippings, breaker failure etc and to take corrective action.

Recommendations:

KSEBL is recommended to investigate the non-operation of zone selective Busbar Operation at 220/ 110kV Pothencode SS and submit detailed report regarding reasons for the same alongwith remedial measures taken.

KSEBL is recommended to ensure time synchronization of relays at 220/ 110kV Pothencode SS.

Annexure-II


3 Complete outage of 220kV Malaparamba SS of KSEB

29-05-2019 at 01:12 hrs

Triggering incident was R-phase to Earth fault in 220kV MalaparambaAreakode line due to insulator decapping . 220kV Malaparamba Substation was being radially fed from 220kV Areakode


GD-1

SLD: The SLD of 220/ 110 kV Malaparamba SS of KSEBL is attached at the end.

Bus configuration and arrangement: Double bus configuration

Antecedent conditions: Bus-1 connected elements: 220/ 110kV 100MVA Transformer 2 Bus-2 connected elements: 220kV Malaparamba – Areakode line, 220/ 110kV 100MVA

Transformer 1 220kV Malaparamba – Madakathara line was under LC.

Tripping of 220kV MalaparambaAreakode line: Malaparamba (KSEBL) end:

As per FIR/ DR/ TR line tripped at 1:12:03.376 hr. on R-E fault due to operation of DPR Z1 protection. A/R was attempted but line tripped on persisting fault due to decapping of insulator at location number 4 (23.59 km).

Areakode (KSEBL) end:

As per FIR/ DR/ TR line tripped at 1:12:03.376 hr. on R-E fault due to operation of DPR Z2 CAT protection (46.27 km). A/R was attempted but line tripped on persisting fault.

Tripping of 220kV Malaparamba SS:

As per FIR/ TR there was complete loss of supply at 220/ 110kV Malaparamba SS due to tripping of incoming 220kV Malaparamba-Areakode line on operation of distance protection.

KSEBL informed that there are two 220kV feeders at 220kV Substation Malaparamba. One feeder is from Areacode (2MRAR) and other from Madakathara (2MDMR). 2MDMR feeder from Madakathara was under permit for transgrid work. 2MRAR feeder from Areacode tripped on 29-05-2019 at 01-12hrs due de capping of insulator. Thus 220kV supply failed and hence supply

Connectivity diagram of 220/ 110kV Malaparamba SS of KSEBL

220kV Malaparamba

110kV Malaparamba

220kV Madakathara

220kV Areakode

Annexure-II


interrupted for 1MRML1&2, 1MRPT, 1MRME and 110/11kV Transformer No1.

No interruption occurred in 1MRKU1&2 and 110/11kV Transformer No 2 since this supply were through 110kV bus 2 from shornur side. As per the concurrence with LD Kalamassery, feeding to Malappuram substation re arranged from Areacode through 110kV substation Kizhissery, then 110kV bus1&2 at Malaparamba tied and supply restored on all 110kV bays from Shornur side at 1.55hrs on 29-05-2019.

Deliberations:

In the antecedent condition, 220kV Malaparamba – Madakkathara line was under LC for transgrid works and both Buses 1 & 2 was in service.

The triggering incidence was R-E fault on 220kV Malaparamba – Areakode line due to insulator decapping at 1:12:03.376 hr. The line attempted auto-reclosure, but since the fault was persisting in nature line tripped in 3-ph. Hence, the supply to 220kV bus was lost and it resultedin outage of 220kV Bus 1 & 2. But 110kV Bus-2 was fed from 110kV Shornur SS, so there was not complete loss of supply at the station.

KSEBL had informed that feeding to malaparamba substation was re arranged from Areacode through 110kV Kizhissery SS, and 110kV bus 1 & 2 at Malaparamba were tied and supply restored on all 110kV bays from Shornur side at 1.55hrs on 29-05-2019.

Remedial Measures Taken: KSEBL informed that after the tripping, measure has been taken to ensure reliable supply to

220kV Malaparamba SS through 220kV Madakkathara – Malaparamba lines 1 &2.

Annexure-II


4

Tripping of 220kV Sedam-RTPS line-1&2 and 220kV Sedam-Tandur line

14-06-2019 at 02:00 hrs

Tripped on Directional Earth Fault indications in Main-2 relay at Tandur end for fault at Raichur end. Sedam end details not furnished.

GI-1

SLD: The SLD of 220/ 110 kV Sedam SS of KPTCL is attached at the end.

Bus configuration and arrangement: Double bus configuration Bus 1- 220kV Sedam – Humnabad line-1, 220kV Sedam – RTPS line-2, 100 MVA

Tranformer-1, 220kV Sedam– Shree cements line, 220kV Sedam – Tandur line. Bus 2- 220kV Sedam –Shahapur line, 220kV Sedam – Humnabad line-2, 220kV Sedam

Orient cements line , 220kV Sedam RTPS line-1, 220kV Sedam - cleanmax solar line

Tripping of 220kV Sedam – RTPS line-1: Sedam ( KPTCL) end:

As per FIR/ TR line did not trip at Sedam end. RTPS (KPCL) end:

As per FIR/ EL line tripped at 01:59:47.906 hr. on operation of DPR Z3 protection (Tz3=750msec) Tripping of 220kV Sedam – RTPS line-2: Sedam ( KPTCL) end:

As per FIR/ TR line detected B-E fault in Z-1 due to operation of Distance protection (1.38kA) but did not trip due to mechanical problem with the line CB at Sedam end.

RTPS (KPCL) end:

As per FIR/ EL line tripped at 01:59:47.103 hr. on operation of DPR Z1 protection (9.05 kA; 13.1 km)

Tripping of 220kV Sedam – Tandur line: Sedam ( KPTCL) end:

As per FIR/ TR line did not trip at Sedam end. Tandur (TSTRANSCO) end:

Sedam RTPS

Humnabad

Shree cements

Orient cements

Shahpur

Tandur Clean Max solar

Annexure-II


As per FIR/ DR/ EL/ TR line tripped at 02:00:06.353 hr. on operation of Directional Earth fault protection. (Td=2.8msec)

Deliberations:

In the antecedent condition 220kV Sedam-Shahapur line was under LC due to line fault and the station was under single bus operation.

At 01:59:47 hr. B-E fault occurred on 220kV Sedam – RTPS line-2. The fault was detected in Z-1 at both ends. RTPS end tripped immediately but Sedam end breaker did not open due to CB mechanical problem. A/ R was not in service for the line.

Hence fault was cleared by operation of protection at remote end. 220kV Sedam – Humnabad line- 1 & 2, 220kV Sedam – Tandur line tripped at remote end on DEF operation. 220kV Sedam RTPS line-1 tripped at RTPS end on operation of DPR Z3. All remaining lines were radially fed from Sedam end. Hence no protection operated at remote end. This has led to complete outage of 220kV Sedam SS.

Remedial Measures Taken: KPTCL vide mail dated 30.07.2019 informed that:

The Circuit Breaker of RTPS-1 &2 lines which was due for replacement has been replaced on 24th and 25th July 2019.

The control cables required for Bus Bar Protection work has been arranged, the work is expected to be completed by August end.

Recommendations: KPTCL is recommended to enable A/R on all lines emanating from 220kV Sedam SS. KPTCL is recommended to commission BBP at 220kV Sedam SS immediately.

II. Details of Grid Incidents:

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

y

1 Tripping of 400/230kV MANALI ICT-3

13-05-2019 at 2:42 hrs

ICT-3 got tripped on the activation of HV REF protection. During test charging of 110 kV Manali-ETPS -1 , the 110 kV ETPS -1 got tripped on the activation of Back up relay and Distance relay failed to act

GI-2

Annexure-II


MANALI (TANTRANSCO) end:

As per FIR/ DR/ EL/ TR ICT-3 tripped on HV side at 02:42:54.570 hr. due to operation of HV REF protection.

TANTRANSCO in their TR informed that during test charging of 110 kV Manali- ETPS -1, the line got tripped on the activation of Back up O/C protection and Distance relay failed to act. The earth conductor of line got cut and fell on 110 kV Manali- TPL # Line conductor. 110 kV Manali- TPL line got tripped on Distance relay activation with Z-1 trip. Both ICTs kept feeding the fault upto 1.1 secs. During this time the ICT-3 got tripped on the activation of HV REF protection. But 400/110 kV, 200 MVA, ICT-1 was in service and hence no interruption to the 110 kV Loads. Deliberations:

In the antecedent condition 110kV Manali –ETPS line -1 was out of service. During testcharging of 110kV Manali –ETPS line -1 from Manali end, B-E fault occurred on the line. But SOTF did not pick for the fault. During this time, 400/230kV ICT-3 at Manali tripped on operation of HV REF protection(Differential current is present in REF protection DR for 3 cycles). The operation of ICT REF protection for through fault needs review.

The fault wascleared by operation of Overcurrent protection of the line after 1.1 sec.

When enquired about non-operation of SOTF protection of 110kV Manali –ETPS line -1, TANTRANSCO informed that the distance relay at Manali end was configured from Bus PT and it was changed to line PT after the fault.

After 1.3sec after the fault, earth conductor of 110kV Manali –ETPS line -1 got cut and fell on 110 kV Manali -TPL line conductor creating Y-E fault. The fault was cleared by tripping of 110kV Manali – TPL line due to operation of distance protection.

Remedial Measures Taken: TANTRANSCO informed that the operation of ICT HV REF protection for through fault has been

sent to Relay OEM (M/s. NR Ltd) for analysis.

Recommendations: TANTRANCO is recommended to sort out the malfunctioning of ICT Ref protection in

consultation with OEM and submit a detailed report regarding the same in 1 month time. TANTRANSCO is recommended to ensure proper labelling of all digital signals in Disturbance

recorders of lines and ICTs at Manali SS.

2 Tripping of 400kV Madurai-Udumalpet line

16-05-2019 at 18:54 hrs

400kV Udumalpet Madurai line tripped only at Udumalpet end on line under frequency protection operation due to suspected R-ph CVT problem.

GI-2

Madurai (PGCIL –SR-2) end:

As per FIR line did not trip at Madurai end. Udumalpet (PGCIL –SR-2) end:

As per FIR/ DR/ EL/ TR line tripped at 18:54:44.201 hr. on operation of under frequency protection.

As per DR R-ph voltage is observed to be 76.256kV.

PGCIL-SR-2 informed in TR that Underfrequency relay operated due to suspected CVT problem. Deliberations:

400kV Madurai-Udumalpet line tripped at 18:54:44.201 hr. on operation of

Annexure-II


underfrequencyprotection. R-ph voltage waveform was observed to be distorted in line DR. PGCIL –SR-2 informed that underfrequency protection was enabled on the line as part of Neyveli islanding scheme. On analysis, R-ph CVT was found to be proper, but cable from CVT to relay was found to have leakages and this led to spurious underfrequency operation.

Remedial Measures Taken: PGCIL (SR-2) informed that R-ph CVT cable has been replaced after the incidence.

3 Tripping of 400kV Kurnool-Srisailam line

17-05-2019 at 14:10 hrs

line tripped only at Srisailam end on Zone-3 distance protection operation during Y phase to B phase fault in 220kV NarnoorSomayajulapalli line-1

GI-2

Kurnool (APTRANSCO) end:

As per FIR line did not trip at Kurnool end. Srisailam LB (TSGENCO) end:

As per FIR/ EL/ TR line tripped at 14:10 hr on R-B-E fault due to operation of DPR, Z3.

As per EL line picked up in Zone-3 for R-B-E fault at 14:09:44.417 hr.

Deliberations:

In the antecedent conditions, 220kV NarnoorSomayajulapalli line-1 was idle charged from Somayajulapalli end. While testcharging the line it tripped on Y-B fault due to operation of DPR Z1 protection. 400kV Kurnool-Srisailam line tripped from Srisailam end at 14:09:44.417 hr on operation of DPR Z3 protection for Y-B fault on 220kV NarnoorSomayajulapalli line-1. TSGENCO informed that the tripping was due to wrong PSL logic in Micom P442 relay which issues trip without any time delay for 2ph and 3ph faults occuring in any zone.

Remedial Measures Taken: TSGENCO vide mail dated 29.05.2019 and 25.07.2019 had informed that the setting of Z3 time

delay for 400kV Kurnool – Srisailam line is 1.5sec. But the line is tripping instantaneously without any time delay in Zone-3 for LL faults occurring in Kurnool line. In Micom P-442 PSL logic 2Ph fault signal was programmed to the trip relay without any time delay. This signal will issue the trip whenever a two phase fault occurred in the system without waiting the time delay. (In this case Rph to B pH fault occurred i.e 2PH fault occurred in the system). For rectification of Zone-3 fault without any time delay, DR was sent to GEC ALSTOM (OEM) and informed to change the PSL logic.

PSL Logic of Micom P442 relay for 400kV Kurnool Srisailam line

Annexure-II


Recommendations: TSGENCO is recommended to modify the PSL logic (Srisailam end to trip for faults occurring in

Zone-2 and Zone-3 with respective time delays except for PUR scheme if adopted ) in 1 month time to avoid occurrence of any such unwarranted trippings in future.

APTRANSCO to ensure time synchronization of relays at 220kV Somayajulapalli SS.

4 Tripping of 220kV Ambewadi-Ponda line

18-05-2019 at 12:13 hrs

B phase to Earth fault in the line. Line tripped on Zone 3 distance protection operation at Ambewadi end

GI-1

Ambewadi (KPTCL) end:

As per FIR/ DR / EL/ TR line tripped at 12:12:09.118 hr. on B-E fault due to operation of DPR Z3. (45.9km; Ir- 0.22 kA, Iy – 0.24 kA, Ib – 0.57 kA; T Z3 = 1 sec)

Ponda (GED) end:

The line being radial did not trip at Ponda end.

KPTCL informed vide mail dated 30.07.2019 that : At Ambewadi: At 14.10.14.420: M-I relay which picked up when B phase voltage dipped to 106kV, fault current 70A IN reached 335A dropped out after 120msec as fault was no longer persisting. However, Main-II relay (Siemens make) which picked up with Zone-3, BN fault (Fault current 350A, 45.9km) issued trip command after set zone-3 time delay of 1 second. Nature of Fault: Suspected high resistive transient fault in the line.

Deliberations:

220kV Ambewadi-Ponda line tripped from Ambewadi end, at 12:12:09.118 hr. on B-E fault due

Annexure-II


to operation of directional earth fault protection. PTCL informed that Main-1 and Main-2 relays at Ambewadi are Seimens 7SA522 and Micom P442. Micom relay picked up and dropped for the fault. But in Seimens relay zone pick up was used to provide directionality feature for Overcurrent and DEF protections.

Also Zone settings were also high which led to pickup of relay in Zone-3 and DEF operated after 1 sec.

Remedial Measures Taken: KPTCL informed vide mail dated 30.07.2019 that : The healthiness of Siemens make new Main-II relay is checked once again after the incident and

the relay is found to be working satisfactory for all fault conditions. The reach of Zone-3 has been reduced to avoid such unnecessary trippings in future. DEF protection has been normalized in Seimens relay and has been made independent of Zone

pick up. To provide directionality feature to OCR protection Zone-5 has been used.

5 Tripping of 400/220 kV ICT-3 at Nelamangala substation

19-05-2019 at 16:11 hrs

As per FIR, ICT-3 got tripped on operation of High Set Over current trip on 400kV side

GI-2

Connectivity diagram of 400/ 220kV Neelamangala SS of KPTCL: Neelamangala (KPTCL) end:

As per FIR/ DR ICT-3 tripped on both sides at 16:55:13.114 hr. on operation of High Set O/C operation.

KPTCL vide mail dated 30.07.2019 informed that 220kV DB Pura was radially fed from Nelamangala SS through Nelamangala-DB Pura D/c line. At 16.11Hrs 220kV Nelamangala-DB Pura line-1& 2 tripped on operation of M-I&M-II,Zone-1 due to snapping of earth wire near Nelamangala switchyard. Tripping of both the incoming lines to DB Pura resulted in complete outage of the SubStation.Along with this, 500MVA ICT-3 tripped at Nelamangala on HV side OC High set element.

Also, Nelamangala-Magadi line tripped on SOTF O/c pick up. Deliberations:

In the antecedent conditions 400/ 220kV ICT-1 & 2 were connected in parallel at Bus-1. Bus coupler was in open condition. Bus 1 & Bus-2 was connected through 220kV DB pura line -1 & 2

Annexure-II


to reduce shortcircuit level at Neelamangala bus.

The triggering incidence was B-E fault on 220kV Neelamangala DB Pura line-1 and 2 at 16:10:53 hr. due to snapping of the earth wire during heavy rain. The line tripped due to operation of DPR Z1 protection. A/R was disabled on the line. KPTCL informed that auto-reclosure will be made available for the line immediately after retrofitting works are completed at D.B. Pura SS.

Delayed clearance of the fault was due to the fact that the fault started as high resistance fault and subsequently was picked up in zone-1. Tripping of both the incoming lines to DB Pura resulted in complete outage of the Sub Station.

During this time 400/220 kV ICT-3 at Nelamangala substation tripped on operation of HV High Set O/C protection.

At 16:10:54 hr. 220kV Nelamangala-Magadi line tripped on B-E fault due to operation of SOTF protection. When enquired about reason for SOTF protection, KPTCL informed that the logic implemented in relay did not include breaker status, hence it operated based only on the fault current.

Remedial Measures Taken: KPTCL vide mail dated 30.07.2019 informed that:

The line fault was attended. ICT-3 high set setting is revised to 5 Amp from existing 4.3A; Time delay of 100msec is

also provided to the high set. SOTF logic reviewed in Magadi line distance relay (breaker status also included in logic).

Recommendations:

KPTCL is recommended to enable auto-reclosure on all lines emanating from 400/ 220kv Neelamangala SS and to ensure time synchronization of relays at Neelamangala SS.

6 Tripping of 400/220 kV ICT-2 at Ghani substation

21-05-2019 at 15:13 hrs

ICT-2 tripped on LV Earth fault protection. 400kV Ghani-Narnoor line-1 had tripped on B-phase to earth fault.

GI-2

Tripping of 400kV Ghani-Narnoor line-1 : Ghani (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped in 3-ph at 15:13:28.605 hr. on B-E fault due to operation of

Annexure-II


DPR Z1. The Main CB was already open and line was connected though Tie CB only. Tie CB did not attempt A/R.

Narnoor (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped in B-phat 15:13:28.627 hr. on B-E fault due to operation of DPR Z2, CAT. A/R was successful but line tripped in 3-ph at 15:13:29.715 hr. on persisting fault due to operation of DPR 2 (since no carrier received, tripped with TZ2 delay).

Tripping of 400/ 220kV ICT-2 Ghani : Ghani (APTRANSCO) end:

As per FIR/ DR/ EL ICT-2 tripped on both sides at 15:13:29.776 hr. due to operation of LV DEF protection. ( Td= 1.15 sec)

Deliberations:

The triggering incidence for the tripping was B-E fault at 15:13:28 hr. on 400kV Ghani-Narnoor line-1. In antecedent condition Main CB was already open and Tie CB issued 3-ph trip (did not attempt A/R) on operation of distance protection Z1. Narnoor end attempted autoreclosure on operation of DPR Z2 CAT. But since the fault was persisting in nature subsequently tripped in 3-ph. But during 3-ph tripping since no carrier was received from Ghani end (since Ghani end already open)Narnoor end tripped with a Zone-2 delay of 350msec.

During this fault, 400/ 220kV ICT-2 at Ghani SS tripped due to operation of LV DEF protection. APTRANSCO informed that the self reset contact of ICT DEF relay got latched and hence it did not reset inspite of fault current reducing to zero. This led to tripping of ICT.

Remedial Measures Taken: APTRANSCO informed that the reset contact of DEF protection relay has been replaced with

new contact.

Recommendations: APTRANSCO is recommended to send a detailed report regarding non-availability of Main CB

(Main CB was already in tripped condition in antecedent condition) during the tripping and non-attempt of auto-reclosure by Tie CB at Ghani end.

7 Tripping of 400/220 kV ICT-3at Mamidapalli

21-05-2019 at 20:43 hrs

ICT tripped on PRV-1 indications due to ingress of moisture into the relay

GI-2

Mamidapalli (TSTRANSCO) end:

As per FIR/ EL ICT-3 tripped on PRV-1 indications due to ingress of moisture into the relay.

Remedial Measures Taken:

TSTRANSCO informed that they cleaned the moisture and charged the ICT.

Recommendations: TSTRANSCO is recommended to ensure proper sealing of PRV by providing suitable canopy to

prevent spurious operation of the same due to ingress of moisture.

Annexure-II


8 Tripping of 765/400kV ICT-1 and 2 at Kurnool substation

21-05-2019 at 18:11 hrs

ICT 1 and 2 got tripped due to maloperation of Bucholz relays during the charging of 400KV Kurnool-Nanoor line 1 which tripped on SOTF

GI-2

765/400kV ICT – 1 Kurnool (PGCIL –Sr-I) end:

As per FIR/ DR/ EL TR ICT-1 tripped at 18:11:18.757 hr. on operation ofBucholz relay during the charging of 400KV Kurnool-Nanoor line1 which tripped on SOTF during charging.

As per EL ICT-1 tripped at 18:11:18.777 hr. on operation of IOX protection. 765/400kV ICT – 2 Kurnool (PGCIL –Sr-I) end:

As per FIR/ DR/ EL TR ICT-2 tripped at 18:11:18.758 hr. on operation of Bucholz relay during the charging of 400KV Kurnool-Nanoor line1 which tripped on SOTF during charging.

Deliberations:

In the antecedent condition, 400KV Kurnool-Nanoor line 1 was under shutdown. While testcharging the line from Kurnool end at 18:11:18 hr.line tripped on 3ph-E fault due to operation of SOTF protection.

But during the incidence, 765/400kV ICT-1 and 2 at Kurnool SS tripped due to operation of Buchholz relay. The operation of Buchholz relay for ICT through fault needs investigation.

Remedial Measures taken: PGCIL-SR-1 informed vide mail dated 28.07.2019 that ICTs fed the through fault current on

account of fault in 400kV Kurnool-Narnoor line-1 & tripped on operation of Buchholz Relay. Line Fault Current Ia - 34.90kA (RMS), Ib - 33.66kA (RMS), Ic - 41.99kA (RMS). ICT1 also got tripped due to high through fault. Reasons for momentary operation of Buchholz Relay for through fault may be due to

i. Vibration of pipe connected between the Conservator & Main Tank. ii. Operation of Trip contact for oil surge during the through fault.

Cedapse, Italy make Buchholz relay of Model number- EE3-MA at Kurnool SS are mal operated for the through faults . Informed to OEM to take corrective modification. Awaiting for OEM response. OEM planned to visit the Kurnool SS for rectification in 1st week of August-2019.

Recommendation: PGCIL (SR-I) is recommended to submit a detailed report regarding operation of Buchholz relay

of 765/ 400kV ICT 1& 2 during through fault after consultation with OEM along-with the remedial measures taken to prevent occurrence of any such incidence in future.

9 Tripping of 220KV Sabarigiri-Theni line

23-05-2019 at 16:12 hrs

Line tripped on operation of DEF at Theni end

GI-1

Theni (TANTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 16:11:51.111 hr. on R-E fault due to operation of DEF protection ( Td= 3.1ec ( if calculated from earlier IN pick up ); 0.97kA)

Sabarigiri (KSEBL) end:

As per FIR/ DR/ EL/ TR line tripped at 16:11:51.111 hr. on R-E fault due to operation of DPR Z2 protection. (100.3km, Td = 625msec)

Deliberations:

220KV Sabarigiri-Theni line tripped at 16:11:51.111 hr. on R-E fault due to operation of DEF protection at Theni end and DPR Z2 protection at Sabarigiri end. KSEBL informed that due to the high resistance nature of fault, it was detected after some delay in Zone-2 hence the tripping was after 625msec after the fault.

Recommendations: KSEBL is recommended to configure in DR and EL the pick up and operation of relevant distance

protection zones in the event of distance protection operation.

Annexure-II


10 Tripping of 400kV Sigareni-Sundilla line-2

24-05-2019 at 18:21 hrs

Line tripped to operation of OV Stg-1 protection operation at Sundila end and DT received at Singareni end. Difference in phase voltages is observed at Sundilla end DR (Vr-262kV, Vy-240kV and Vb-214kV).

GI-2

Singareni (STPP) end:

As per DR/ EL line tripped at 18:21:57.612 hr. on receipt of DT from Sundilla end. Sundilla (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 18:21:52.847 hr. on operation of OVR Stg.-1 protection. ( TOV – 8sec; Vr- 262kV, Vy-240.079kV, Vb-214.42kV).

OVR grading (2019) at 400kV Sundilla SS :

Remedial Measures taken: TSTRANSCO informed that the CVT’s and relays has been checked by OEM and everything has

been found normal. Also new OVR grading has been adopted at 400kV Sundilla SS.

11 Tripping of 400kV Hoody-Yelahanka line-1

25-05-2019 at 20:41 hrs

Line tripped at Hoody end only and was holding from Yelahanka.

GI-2

Hoody (KPTCL) end:

As per FIR/ DR/ EL/ TR line tripped at 20:37:32.242 on operation of DPR Z1 or SOTF/TOR.

As per EL distance B-ph pickup observed. But as per DR no fault current but instantaneous voltage 0 in all 3-phases for a short time.

Yelahanka (PGCIL-SR-2) end:

As per FIR/ TR line did not trip at Yelahanka end.

KPTCL vide mail dated 30.07.2019 informed that at 20.37.32.201: Main-I relay operated in Zone-1. Fault duration: 3.336ms; Sudden dip in voltage observed in all the three phases for about 40msec; M-II has not operated during the moment.

At Yelahanka: Line was holding from Yelahanka end

Reason: Suspected momentary problem in secondary voltage circuit of M-II relay

Deliberations:

400kV Hoody-Yelahanka line-1 tripped only at Hoody end at 20:37:32.242 hr. on operation of SOTF protection. The Main-1 relay (Micom P444) picked up for momentary voltage problem and issued trip.

Recommendations: KPTCL is recommended to check the spurious operation of SOTF protection at Hoody SS and

submit a report to SRPC regarding the same .

Annexure-II


12 Tripping of 400/220 kV ICT-1at Guttur Substation

26-05-2019 at 10:00 hrs

LV side of 400kV/220kV 315MVA ICT#1 Guttur got tripped due to CB lockout (B phase)because of low SF6 gas in the CB

GI-2

Guttur (KPTCL) end:

As per FIR/ DR/ EL/ TR ICT-1 tripped on LV side at 10:00:51.355 hr. on operation of CB lockout trip due to low SF6 gas pressure in B-ph CB.

KPTCL vide mail dated 30.07.2019 informed that220kV side CB of ICT-1 was replaced by CGL make new CB recently.SF6 leakage was observed in B phase limb, hence, operating personnel attempted to recharge the pressure in the cylinder. The cylinder used for recharge was having lower pressure hence, when connected to breaker pressure flowed from CB to cylinder and CB tripped on low SF6 gas pressure.

Remedial Measures Taken: KPTCL vide mail dated 30.07.2019 informed that SF6 gas leakage problem in the breaker is

attended by the OEM.However small leakage still persists .The issue is referred to the OEM and OEM is yet to depute their personnel.

Recommendations: KPTCL is recommended to submit a report to SRPC after the CB pressure leakage problem is

attended by OEM. KPTCL to ensure that during recharging of Circuit breakers, cylinders with Non-return valve only

are used to prevent sudden pressure drop in Circuit breakers.

13 Tripping of 400kV NPS Nellore line-1 & 2

27-05-2019 at 17:42 hrs

400kV NPS Nellore-PG line-2 tripped at NPS end due to suspected maloperation of group B protection and DT was sent to Nellore-PG end. 400kV NPS Nellore-PG line-1 got tripped due to operation of SPS

GI-2

Tripping of 400kV NPS Nellore line-1 : Nellore PG(PGCIL-Sr-1) end:

As per FIR/ DR/ EL/ TR line tripped at 17:42:39.572 hr. on receipt of DT due to SPS operation on tripping of 400kV NPS Nellore line-2.

Nellore PS (PGCIL-Sr-1) end:

As per FIR/ DR/ EL/ TR line tripped at 17:42:39.527 hr. due to SPS operation on tripping of 400kV NPS Nellore line-2.

Tripping of 400kV NPS Nellore line-2 : Nellore PG(PGCIL-Sr-1) end:

As per FIR/ DR/ EL/ TR line tripped at 17:42:34.423 hr. on receipt of DT from Nellore PS end. Nellore PS (PGCIL-Sr-1) end:

As per FIR/ DR/ EL/ TR line tripped at 17:42:34.401 hr. due to operation of Group B trip relay.

Deliberations:

400kV NPS Nellore line-2 tripped due to maloperation of Group B (86B) trip relayat Nellore PS end and DT was sent to Nellore PG end. Consequently 400kV NPS Nellore line-1 tripped on SPS operation. Operation of protection system is stated to be in order.

Remedial Measure Taken: PGCIL (Sr-1) vide mail dated 28.07.2019 informed that 400kV NPS Nellore Line-2 tripped due to

86B trip relay maloperation. 86 B trip relay replaced with spare relay and line taken into service.

Annexure-II


14 Tripping of 230kV Theni-Sabarigiri line

29-05-2019 at 18:39 hrs

3 phase to earth fault occurred in line. Tripped on ground over current protection 67N at Sabarigiri and Zone-2 at Theni end.

GI-1

Theni (TANTRASCO) end:

As per FIR/ DR/ EL/ TR line tripped at 18:38:45.979 hr. on R-Y-B fault due to operation of DPR Z2 protection. (96.998 km; 3.05kA; TZ2 = 350msec)

Sabarigiri (KSEBL) end:

As per FIR/ DR/ EL/ TR line tripped at 18:39:20.987 hr. on R-Y-B fault due to operation of DPR Z1 protection (16.6 km; Ir-6.55 kA, Iy-7.16 kA, Ib- 6.67kA; TZ1 = 100msec).

Deliberations:

230kV Theni-Sabarigiri line tripped on R-Y-B fault due to operation of distance protection. Sabarigiri end, fault was detected in Zone-1 and carrier was sent but Theni end did not receive the carrier and hence tripped only after Zone-2 time delay. TANTRANSCO requested KSEBL to replace the PLCC panel at their end so as to ensure same make PLCC at both ends.

Recommendations: For the subject line, the following shall be carried out by TANTRANSCO in coordination with

KSEBL: (i) End-to-end testing for DT/ permissive & other signals may be ensured by testing at both the

ends. (ii) Healthiness of PLCC system components ( hardware and software) at both the ends shall be

checked and faulty components shall be repaired/ replaced .

15 Tripping of 400/220 kV ICT-1 and 400kV RTPS-RAICHUR PG line-2

29-05-2019 at 12:43 hrs

Due to spurious operation of Tie breaker LBB, 400/220 kV ICT-1 and 400kV RTPS-Raichur PG 2 got tripped at RTPS end and DT was sent to Raichur PG end

GI-2

Tripping of 400/220 kV ICT-1 Raichur TPS (KPCL):

As per FIR/ DR/ EL/ TR ICT-1 tripped at 12:43 hr. on operation of Tie CB LBB protection. Tripping of 400kV RTPS – Raichur PG line -2: RTPS (KPCL):

As per FIR/ DR/ EL/ TR line tripped at 12:43 hr. on operation of Tie CB LBB protection and DT was sent to Raichur PG end.

Raichur PG (PGCIL- SR-1) end:

As per FIR/ DR/ EL/ TR line tripped at 12:43:39.954 hr. on receipt of DT from remote end. Deliberations:

Tripping of 400kV RTPS – Raichur PG line -2 and 400/ 220kV ICT-1 at Raichur was due to maloperation of Tie CB LBB protection. KPCL informed that the contact multiplier relay of Tie LBB was MVAJHM53 type which had been retrofitted with MVAJM25 relay. The retrofitted relay maloperated and caused tripping of 400/220 kV ICT-1 and 400kV RTPS-RAICHUR PG line-2.

Remedial Measures Taken: KPCL informed that the Tie CB LBB trip at RTPS was recently retrofitted from VAJHM53 with

MVAJM25 on 02.05.2019. The faulty trip relay MVAJM25 replaced with spare relay and the contacts used for DT has been incorporated in the LBB relay.

Annexure-II


16

Tripping of 400kV Tumkur-Bidadi line-1&2, 400kV Tumkur-Cuddapah line-2, 400kV Tumkur-Pavagada line-2

29-05-2019 at 6:11 hrs

Lines tripped due to Y-N & Y-B phase to earth fault

GI-2

Tripping of 400kV Tumkur – Bidadi line 1: Tumkur (PGCIL –SR-2) end:

As per FIR/ TR line did not trip at Tumkur end. Bidadi (PGCIL –SR-2) end:

As per FIR/ DR/ EL/ TR line tripped at 06:11:03.304 hr. on Y-B fault due to operation of DPR Z2 CAT.

Tripping of 400kV Tumkur – Bidadi line 2: Tumkur (PGCIL –SR-2) end:

As per FIR/ DR/ EL/ TR line tripped at 06:11:03.293 hr. on operation of DPR Z1. Bidadi (PGCIL –SR-2) end:

As per FIR/ DR/ EL/ TR line tripped at 06:11:03.308 hr. on Y-B fault due to operation of DPR Z2 CAT.

Tripping of 400kV Tumkur – Cuddapah line 2: Tumkur (PGCIL –SR-2) end:

As per FIR/ DR/ EL/ TR line tripped in Y ph at06:11:02.038 hr. on Y-E fault due to operation of DPR Z1 protection. A/R was attempted but subsequently line tripped in 3-ph due to persisting fault.

Cuddapah (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR line tripped in Y ph at 06:11:02.009 hr. on Y-E fault due to operation of DPR Z2 CAT protection. A/R was attempted but subsequently line tripped in 3-ph due to persisting fault. (248.5 km; FC:2.71 kA)

Annexure-II


Tripping of 400kV Tumkur – Pavagada line 2: Tumkur (PGCIL –SR-2) end:

As per FIR/ DR/ EL/ TR line tripped at 06:11:03.292 hr. on Y-B-E fault due to operation of DPR Z1 protection. The fault was due to B-ph LA failure at Tumkur end.

Pavagada (PGCIL –SR-2) end:

As per FIR/ DR/ EL/ TR line tripped at 06:11:03.298 hr. on Y-B-E fault due to operation of DPR Z2 CAT protection.

Deliberations:

The triggering incidence was Y-E fault on 400kV Tumkur – Cuddapah line 2, the line attempted A/R but tripped due to persisting fault. During same time B-ph LA of 400kV Tumkur – Pavagada line 2 failed at Tumkur end and it was detected as Y-B-E fault and the line tripped. At the same time another Y-B fault was detected in 400kV Tumkur – Bidadi line 2 and it tripped on operation of Distance protection. But 400kV Tumkur – Bidadi line 1 also tripped at Bidadi end on Z2 CAT.

PGCIL (SR-2) informed that Main 2 relay (GE P444) at Tumkur end of 400kV Tumkur – Bidadi line 1 maloperated (due to problem with relay software) and sent carrier to Bidadi end. Hence, Bidadi end tripped immediately (Z2 CAT).

Remedial Measures Taken: PGCIL (SR-2) informed that the failed LAof 400kV Tumkur – Pavagada line 2 was replaced and

line taken back into service. The maloperated relay software was upgraded to new version (D4.7 ) by OEM.

Recommendations:

PGCIL (SR-2) is recommended to submit Equipment failure report to CEA regarding the failed LA.

17

400 kV Ghani – Narnoor line-1, 400 KV Jamalamadugu-Kurnool line-1, 765/400 kV ICT-1&2 at Kurnool

30-05-2019 at 00:48 hrs

Triggering incident was Y-ph to B-ph fault in the 400kV NarnoorJammalamadugu line-1 & 2 due to falling of Y-ph CVT jumper on B-ph during heavy wind. At the same time, 400kV GhaniNarnoor tripped only at Ghani end on operation of Zone-1 distance protection. 765/400 kV ICT-1 & 2 at Kurnool PG also got tripped on HV side Directional Overcurrent (DOC) protection.

GI-2

Tripping of 400kV Ghani – Narnoor line-1:

Annexure-II


Ghani (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 00:48:13.076 hr. on Y-B fault due to operation of DPR Z1 protection (19.7 km). [ Iy=758A, Ib=769A]


As per FIR line did not trip at Narnoor end. Tripping of 400kV Jamalamadugu – Narnoor line-1: Jamalamadugu (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 00:47:55.948 hr. on Y-B fault due to operation of DPR, Z2 CAT protection. (89.7 km)


As per FIR/ DR/ EL/ TR line tripped at 00:48:13.079 hr. on Y-B fault due to operation of DPR Z1 protection. The fault was due to Y-Phase CVT jumper cut and fallen on B-Phase Jumper.

In DR Y ph voltage is not present for 600msec. and SOTF/ TOR signal also raised at 00:48:13.054 hr.

Tripping of 400kV Jamalamadugu – Narnoor line-2: Jamalamadugu (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 00:47:55.950 hr. on Y-B fault due to operation of DPR, Z2 CAT protection. (94.7 km)


As per FIR/ DR/ EL/ TR line tripped at 00:47:55.934 hr. on Y-B fault due to operation of DPR Z1 protection. The fault was due to Y-Phase CVT jumper cut and fallen on B-Phase Jumper. (0.93 km)

Tripping of 765/ 400kV ICT-1 Kurnool:

As per FIR/ DR/ EL/ TR ICT-2 tripped at 00:47:55.991 hr. on Y-B fault due to operation of DOC ( Highset, If < 5kA)

Tripping of 765/ 400kV ICT-2 Kurnool:

As per FIR/ DR/ EL/ TR ICT-2 tripped at 00:47:55.9922 hr. on Y-B fault due to operation of DOC ( Highset, If <5kA)

PGCIL (SR-1 ) vide mail dated 28.07.2019 informed that 1500MVA ICT-1&2 at Kurnool tripped on operation of Bucholz-1 operation. ICTs fed the through fault current on account of fault in 400kV Ghani-Narnoor line & Jammalamadugu-Narnoor-1&2 & tripped on operation of Buchholz Relay. Line Fault Current Ib - 4.90kA (RMS), Ic - 3.99kA (RMS).

Reasons for momentary operation of Buchholz Relay for through fault may be due to i. Vibration of pipe connected between the Conservator & Main Tank. ii. Operation of Trip contact for oil surge during the through fault.

Cedapse, Italy make Buchholz relay of Model number- EE3-MA at Kurnool SS are mal operated for the through faults . Informed to OEM to take corrective modification. Awaiting for OEM response. OEM planned to visit the Kurnool SS for rectification in 1st week of August-2019.

Deliberations:

The triggering incidence was Y-Phase CVT jumper cut and falling on B-Phase Jumper creating Y-B fault on 400kV NarnoorJamalamadugu lines 1 & 2 tripping them on operation of Distance protection. The fault was also detected by 400kV Ghani – Narnoor line at Ghani end in Z1 and it tripped. APTRANSCO informed that Seimens 7SA522 relay at Ghani end only operated in Zone-1. The other main relay did not operate. The issue has been referred to OEM and the relay is yet to be tested.

765/ 400kV ICT 1 & 2 at Kurnool SS also tripped for the fault due to operation of Buccholz relay

Annexure-II


and the same has also been referred to OEM by PGCIL (SR-1) Recommendations:

APTRANSCO is recommended to sort out the issues with their distance protection relay (7SA522) which maloperated and caused unwarranted tripping of 400kV Ghani – Narnoor line-1. The time synchronization of relays at Ghani end also shall be ensured.

PGCIL (Sr-1) is recommended to submit a detailed report regarding operation of ICT Buchholz relay for through fault conditions along-with remedial measures suggested by OEM.

18 Tripping of 765/400kV ICT-2 at Kurnool

02-06-2019 at 17:41 hrs

ICT-2 got tripped on operation of Back up directional over current due to through fault (Y-B phase fault).

GI-2

Tripping of 765 KV Kurnool - NPS line-1: Kurnool PG (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR line tripped in 3-ph at 17:41:23.865 hr. on R-E fault due to operation of DPR Z1. The fault was due to jumper dislocation near isolators due to heavy gale winds. A/R not attempted due to PLCC channel failure.

Nellore PS (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR line tripped in 3-ph at 17:41:24.421 hr. on R-E fault due to operation of DPR Z2 (TZ2-0.5 sec). Line tripped in Z-2 time due to non-receipt of carrier due to PLCC channel failure.

Tripping of 765 KV Kurnool - NPS line-2: Kurnool PG (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR line tripped at 17:41:15.815 hr. due to operation of OVR Stg.1 and DT was sent to other end.


As per FIR/ DR/ EL/ TR line did not trip since DT was not received due to PLCC channel failure. Tripping of 765/ 400kV ICT-2 Kurnool (PGCIL –SR-1):

As per FIR/ DR/ EL/ TR ICT-2 tripped at 17:41:23.816 hr. on R-Y fault due to operation of HV side Back up protection.

Annexure-II


PGCIL (Sr-1) vide mail dated 28.07.2019 informed that 1500MVA ICT-2 at Kurnool tripped on DOC due to through fault in 765kV lines which were tripped at same time. Fault due to heavy swing of jumpers and connector damage on heavy gale & rain at Kurnool SS and this caused tripping of 765kV lines also. All damaged connectors were replaced and jumper tightening checked and all elements taken into service.

Deliberations:

At 17:41 hr. 765kV Raichur – Kurnool line tripped on another Y-E fault on operation of distance protection. The line auto-reclosed successfully. But after 2sec, subsequent B-E fault occurred on the line and it tripped in 3-ph.

Simultaneously 765 KV Kurnool - NPS line-1 tripped on Y-E fault due to jumper dislocation near isolators due to heavy gale winds on operation of distance protection. A/r was not attempted due to PLCC channel failure. Subsequently 765 KV Kurnool - NPS line-2 tripped on operation of Overvolatage Stg.-1 protection at Kurnool end. Nellore PS end did not trip since DT was not received due to PLCC channel failure. At the same time 765/ 400kV ICT-2 at Kurnool also tripped on operation of HV side High set O/C protection.

Remedial Measures Taken: PGCIL (SR-1) informed that the terminal connector quality at 765kV Maheshwaram SS is found

to be inadequate and the same has already been replaced. Healthiness of PLCC channel of 765 KV Kurnool - NPS line-1& 2 has been restored.

Recommendations: PGCIL (SR-1) is requested to check the operation of ICT HV side High set O/C protection for

through fault and submit a report regarding the same.

19 Tripping of 400kV JSW-Guttur line

02-06-2019 at 18:17 hrs

Line tripped due to OV St-1 protection operation at JSW end and DT was sent to Guttur end. At Guttur end B ph voltage was observed to be lesser comparing to R ph and Y ph(Vr-249kV, Vy-255kV and Vb-230kV).

GI-2

JSWEL end:

As per FIR/ DR/ EL/ TR line tripped at 18:16:19.203 hr. on operation of OVR stg.-1 protection and DT sent to Guttur end. (Vr= 249kV, Vy=250kV, Vb=230kV, Tov=6sec) [ As per OVR-2018, Grading is F i.e, 110%, 6sec]

Guttur (KPTCL) end:

As per FIR/ DR/ EL/ TR line tripped at 18:09:52.543 hr. on receipt of DT .At the same time OVR stg.-1 protection operated atGutturand DT sent to JSWEL end. (Vr= 251kV, Vy=245kV, Vb=245kV, Tov=12sec) [ As per OVR 2019, Grading is D i.e, 110%, 8sec)

OVR grading (2018 ) at 400kV JSWEL end:

OVR grading (2019 ) at 400kV Guttur end:

Annexure-II


Remedial Measures Taken: KPTCL vide mail dated 30.07.2019 informed that from the Guttur end DR, R phase voltage was

found to be more when compared to Y&B phases. Due to higher ratio error, R phase CVT of JSWEL line at Guttur was tagged for replacement. The suspected CVT has been replaced by new CVT on 25.07.2019.

Recommendations: JSWEL is recommended to monitor the B-ph CVT of 400kV JSWEL-Guttur line (due to lower B-ph

voltage compared to other two phases). The same shall be replaced if the issue persists.

20 Tripping of 220kV Idukki-Udumalpet line

05-06-2019 at 15:13 hrs

Triggering incident was R-Y-Earth fault in the line. Carrier aided protection not operated at Udumalpet end.

GI-1

Idukki (KSEBL) end:

As per FIR/ DR/ EL/ TR line tripped at 15:10:09.260 hr. on R-B-E fault due to operation of DPR Z1 protection (I a = 2 . 4 9 6 k A , I b = 3 5 4 . 6 A , I c = 8 . 6 7 2 k A ; 8.962 km)

As per FIR carrier was sent to Udumalpet end. Udumalpet (TANTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 15:06:37.918 hr. on R-B-E fault due to operation of DPR Z2 protection. ( Line tripped with a delay of 350msec)

Recommendations: For the subject line, the following shall be carried out by TANTRANSCO in coordination with

KSEBL: (iii) End-to-end testing for DT/ permissive & other signals may be ensured by testing at both the

ends. (iv) Healthiness of PLCC system components ( hardware and software) at both the ends shall be

checked and faulty components shall be repaired/ replaced .

21 Tripping of 400kV JSW -Guttur line and 400 kV Kaiga - Guttur line-2

05-06-2019 at 18:27 hrs

Y-phase to earth fault occurred in 400kV Kaiga-Guttur line-2. A/r was successful at Guttur end. At Kaiga end A/r was not attempted and breakers got tripped due to operation of Pole discrepancy (1.65 Sec). 400kV JSW-Guttur line tripped on operation of over-voltage at Guttur and direct trip was received at JSW. From DR of Guttur, it is observed that there was swell in R & Y phase voltage for few cycles

GI-2

Tripping of 400kV JSW -Guttur line: JSWEL end:

As per FIR/ DR/EL/ TR line tripped at 18:27:13.103 hr. on receipt of DT from Guttur end. Guttur end:

Annexure-II


As per FIR/ DR/EL/ TR line tripped at 18:28:24.670 hr. on operation of OVR stg. 1 (Vr = 259.160 kV, Vy= 152.718 kV, Vb= 254.238 kV; Tov = 5 sec)[ Grading not followed. Grading issued was D = 110%, 8sec].

Tripping of 400kV Kaiga – Guttur line-2: Kaiga (NPCIL) end:

As per FIR/ DR/ TR line tripped at 18:27:08.314 hr. on Y-E fault due to operation of DPR Z1 protection (132.8 km) and Pole discrepancy operation.

As per EL line tripped at 18:27:06.951 hr.on Y-E fault due to operation of DPR Z1 protection and Pole discrepancy operation.

As per EL OVR stg.-1 operated at 18:27:11.488 hr. [ Grading – F; 110% 6 sec]

Guttur (KPTCL) end:

As per FIR/ DR/ EL/ TR line tripped in Y-ph 18:27:08.347 hr. on Y-E fault due to operation of DPR Z1 protection. The line successfully auto-reclosed but subsequently tripped at 18:27:14.592 hr. due to DT receipt from OVR operation at Kaiga end.

Deliberation:

As per the tripping files 400kV KaigaGuttur line-2 tripped in Y-phat 18:27:08.314 hr. on Y-E fault due to operation of DPR Z1 protection. Tie CB (02C) tripped in 3-ph but Main CB tripped only in Y-ph. After 80msec, Main CB (02B) B-ph also opened.

Due to non-opening of R-ph CB PD operated and tripped the line 1.7 sec after the fault.6 secs after the fault, OVR stg.1 protection also operated. Since OVR pick up not indicated, grading could not be verified.

OVR Grading(2018) at 400kV Kaiga end:

OVR Grading(2019) at 400kV Guttur end:

Remedial Measures Taken: KPTCL vide mail dated 30.07.2019 informed that from the Guttur end DR, R phase voltage was

found to be more when compared to Y&B phases. Due to higher ratio error, R phase CVT of JSWEL line at Guttur was tagged for replacement. The suspected CVT has been replaced by new CVT on 25.07.2019.

Recommendations: NPCIL (KGS) is recommended to identify the issue related to unsuccessful A/R attempt of 400kV

Kaiga – Guttur line and non-opening of R-pole CB. It is recommended to check the healthiness of all breakers including breaker timing.

Time synchronization of DR and EL at Kaiga end shall be ensured.

Annexure-II


22 Tripping of 400kV Dhoni-Munirabad line

06-06-2019 at 02:01 hrs

Line got tripped at Dhoni end. From DR Zone-3 start, PSB and A/r block was observed.

GI-2

Tripping of 400kV Narendra – Guttur Line -1: Guttur (KPTCL) end:

As per FIR/ DR/EL/ TR line tripped at 02:00:57.875 hr. on R-Y fault due to operation of DPR Z1 protection. ( Ir=7.9kA, Iy=9.01kA, 31.6 km)

Narendra (PGCIL –Sr-2) end:

As per FIR/ EL/ TR line tripped at 02:00:57.895 hr. on R-Y fault due to operation of DPR Z1 protection. The fault was due to tower collapse.

As per DR line tripped at 02:00:59.061 hr. on R-Y fault due to operation of DPR Z1 protection. Tripping of 400kV Narendra – Guttur Line -2: Guttur (KPTCL) end:

As per FIR/ TR line tripped on R-Y fault due to operation of DPR Z1 protection. Narendra (PGCIL –Sr-2) end:

As per FIR/ EL/ TR line tripped at 02:02:57.895 hr. on R-Y fault due to operation of DPR Z1 protection. The fault was due to tower collapse.

Tripping of 400kV Dhoni-Munirabad line: Dhoni (KPTCL) end:

As per FIR/ EL/ TR line tripped at 02:01:02.313 hr. on operation of PSB protection. (Tpsb=2 sec) Munirabad (KPTCL) end:

As per FIR/ TR line did not trip at Munirabad end. Deliberations:

KPTCL vide mail dated 30.07.2019 informed that 400kV Guttur-Narendra 1 &2 lines tripped at both the ends on Distance protection at 2.01Hrs as 04 nos of towers collapsed near Medleri village (Tower no:362). M-I & M-II relays of 400kV Dhoni-Munirabad line at Doni have sensed this fault in Zone-3 at 02.00.57.866 hr.However both the relays have dropped after 100msec after clearance of fault in Narendra- Guttur lines. After 2 seconds of the above fault, 400kVDoni-Munirabad line tripped at Doni end on suspected PSB mal operation in Main-1 Siemens relay.The line was holding from Munirabad end.

Remedial Measures Taken: KPTCL vide mail dated 30.07.2019 informed that PSB mal operation is suspected in Main-I

Siemens relay.The issue is referred to the OEM.

Recommendations: KPTCL is recommended to submit a report regarding PSB maloperation along-with the RM

suggested by OEM. Proper legends shall be ensured for digital signals at Doni end.

23 Tripping of 400kV N.P.Kunta-Hindupur line-2

09-06-2019 at 18:14 hrs

R-phase to earth fault occurred in line. Line tripped due to operation of over-voltage stg-2. Voltage swell was observed in DR (R-phase to earth voltage-462kV)

GI-2

NPKunta (PGCIL-SR-1) end:

As per FIR/ DR/EL/ TR line tripped at 18:14:42.854 hr. on operation of OVR stg-2 protection. Hindupur (APTRANSCO) end:

As per DR/ EL/ TR line tripped at 18:14:42 hr. on operation of OVR Stg.-2 Deliberations:

Annexure-II


The triggering incidence for the tripping was R-E fault on 400kV N.P.Kunta-Hindupur line-2. During the fault, at NPKunta end Main CB tripped in 3-ph and Tie CB tripped only in R-ph. Tie CB only attempted Auto-reclosure. During A/R deadtime OVR stg.-2 operated (after 200msec to fault) and line tripped in 3-ph.

24 Tripping of 400kV Vemagiri-Vijayawada line-3

10-06-2019 at 9:18 hrs

line tripped due to mal-operation of line Reactor Differential relay at Vijayawada end and DT was received at Vemagiri end

GI-2

Vemagiri PG (PGCIL-SR-1) end:

As per FIR/ DR/EL/ TR line tripped at 09:18:04.868 hr. on receipt of DT from Vijayawada end. Vijayawada (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 09:18:04.827 hr. on operation of line reactor differential protection.

Remedial Measures Taken: APTRANSCO informed that line reactor differential was found faulty and the relay has been

taken out of service. Faulty relay replaced on 15.06.2019.

25

Tripping of 400kV KTPS-VII - Julurupadu Line-2 & tripping of 400/220kV ICT-1&2 at Julurupadu substation

10-06-2019 at 8:22 hrs

Y-phase to earth fault occurred in 400kV KTPS-VII -Julurupadu Line-2. Operation of over-voltage stg-2 resulted in tripping of line. 400/220kV ICT-1&2 at Julurupadu on operation of over flux protection.

GI-2

Tripping of 400kV KTPS-VII - Julurupadu line-2: KTPS VII (TSGENCO ) end:

As per FIR/ DR/ EL/ TR line tripped at 08:21:54.939 hr. on operation of OVR Stg.-1 protection. (Tov= 7 sec).

Julurupadu (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 08:21:54.961 hr. on receipt of DT from KTPS end. Tripping of 400/220kV ICT-1 at Julurupadu:

Annexure-II


As per FIR/ DR/ EL/ TR ICT-1 tripped on both sides at 08:22:09.016 hr. on operation of Overflux protection.

Tripping of 400/220kV ICT-2 at Julurupadu:

As per FIR/ DR/ EL/ TR ICT-2 tripped on both sides at 08:25:35.975 hr. on operation of Overflux protection.

Tripping of 400kV Julurupadu – Suryapet line-1: Julurupadu (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 08:22:04.002 hr. on operation of OVR stg.-1 protection and DT was sent to Suryapet end. (Tov=6sec)

Suryapet (TSTRANSCO) end:

As per FIR line tripped at 08:22hr. on receipt of DT from remote end. Deliberations:

In the antecedent condition, 400kV KTPS-VII - Julurupadu line -1 was under outage for attending hotspots. 400kV SuryapetJulurupadu 2 was under outage to contain overvoltage. At 08:21 hr. 400kV KTPS-VII - Julurupadu line-2 tripped at KTPS end on OVR stg.-1 operation and at Julurupadu on DT receipt. Subsequently OVR appeared at Manuguru end and tripped 400kV Manuguru – Julurupadu line 2. Then due to overvoltage at Julurupadu, 400kV Julurupadu – Suryapet line-1 tripped. Then both ICT’s at Julurupadu tripped on Overflux protection.

The SCADA plot of 400kV Bus voltage of Julurupadu showed the Bus voltage as very high (478kV).

OVR Grading 2019 at 400kV Julurupadu SS:

OVR Grading 2019 at 400kV KTPS SS:

Recommendations:

TSTRANSCO is recommended to check the v/f settings of ICT-2 at Julurupadu since ICT-1 & 2 tripped at different time ( 3mins difference).

DGA analysis of ICT-2 shall be carried out to ensure healthiness of ICT owing to very high voltage and the tap position of ICT-2 also to be checked.

26 Tripping of 400kV Vemagiri-GMR line-1&2

14-06-2019 at 09:33 hrs

Line-1 tripped on Y-Phase to earth fault due to Y-Phase LA failure at Vemagiri end. Line-2 tripped at GMR end only

GI-2

Tripping of 400kV Vemagiri-GMR line-1: Vemagiri (APTRANSCO) end:

As per FIR/ EL/ TR line tripped at 09:33 hr. on Y-E fault due to LA blast as a result of operation of

Annexure-II


DPR Z1. (24.465 kA)

As per FIR line attempted A/R but tripped due to persisting fault. GMR end:

No tripping files furnished Tripping of 400kV Vemagiri-GMR line-2: Vemagiri (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line did not trip at Vemagiri end GMR end:

No tripping files furnished.

As per SRLDC report line tripped at GMR end on SOTF /TOR trip. Recommendations:

APTRANSCO is recommended to submit Equipment failure report (LA failure) to CEA. GMR is recommended to submit a report regarding tripping of 400kV Vemagiri-GMR line-2 at

GMR end along-with the related tripping files.

27 Tripping of 400/220kV ICT-2 at Hoody substation

16-06-2019 at 19:20 hrs

ICT-2 got tripped on operation of over-flux protection

GI-2

Hoody (KPTCL) end:

As per FIR / DR/ EL/ TR ICT-2 tripped at 19:19:09.170 hr. on operation of HV side Overflux protection operation.

KPTCL informed that B-ph voltage was high due to neutral floating due to loose wiring in voltage circuit.


KPTCL vide mail dated 30.07.2019 informed that:

Loose wire found in voltage circuit rectified. The Over Flux settings have been revised as follows:

v/f setting for alarm: 1.1 time Vnominal, Time delay 20 seconds; v/f trip setting : v/f is 1.2 time Vnominal;Time delay 10 seconds

Recommendations: KPTCL is recommended to adopt v/f settings as per manufacture suggested curve.

v/f setting for alarm: 1.1 time Vnominal; Time delay 10 seconds; v/f trip setting : v/f is 1.2 time Vnominal;Time delay 60 seconds

28 Multiple tripping at 220kV Nunna substation

16-06-2019 at 06:16 hrs

Triggering incident was failure R phase CT of 220/132kV transformer (connected to 220kV Bus-2) in 220kV Nunna station. Bus-2 bus bar protection operated resulting in tripping of elements connected to 220kV Bus-2. 2.63 Seconds later a 2nd fault occurred in Bus-1 due to fault getting extended from Bus-2 CT failure which inturn resulted in tripping of elements connected to 220kV Bus-1

GI-1

Tripping of 220kV Nunna SS

As per FIR/ DR/ EL/ TR Bus-2 at Nunna SS tripped at 04:19:59.735 hr. on operation of Bus Bar Protection due to B-ph CT blast.

Annexure-II


Tripping of 400/ 220kV ICT-1 at Vijayawada (PGCIL-SR-1):

As per FIR/ DR/ EL/ TR 400/ 220kV ICT-1 tripped at 06:15:51.550 hr. due to operation of BBP at 220kV Nunna SS.





Tripping of 400kV KTPS – Nunna line: KTPS (TSGENCO) end:

As per FIR line did not trip at KTPS end. Nunna (APTRANSCO) end:

As per FIR line tripped at 06:16 hr. on operation of Bus Bar protection at 220kV Nunna SS.

Tripping of 220kV Gunadala SS

As per FIR 220kV Nunna – Gunadala lines 1 & 2 tripped at Nunna end due to operation of BBP at Nunna. This led to complete loss of supply to 220kV Gunadala SS.

Deliberations:

Bus configuration : Double Bus with Bus coupler.

The triggering incidence for complete outage of 220kV Nunna SS was failure of B phase CT of 220/132kV transformer (connected to 220kV Bus-2) in 220kV Nunna station. This resulted in operation of Busbar protection for Bus-2.

After 2.63sec, R-ph fault occurred in Bus-1 and led to operation of Busbar protection for Bus-1.

Recommendations: APTRANSCO is recommended to submit Equipment Failure Report regarding the failed CT to

CEA. APTRANSCO to sort out time synchronization issues in 220kV Nunna SS.

29

Tripping of 400kV Hiriyur-Nelamangala line-1 and 400kV Gooty-Nelamangala line

22-06-2019 at 04:06hrs

400kV Hiryur-Nelamangala line-1 : 'Y' phase bushing of Hiriyur line-1 reactor failed at Nelamangala end resuting in a R-Y phase fault. Direct trip was sent to Hiryur. 400kV Gooty-Nelamangalaline : Line tripped at Nelamangala end only due to mal-operation of Main-2 distance protection relay (THR).

GI-2

Tripping of 400kV Hiriyur-Nelamangala line-1: Hiriyur (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR line tripped at 04:06:01.594 hr. on R-Y fault due to operation of DPR Z2 CAT protection. (Ir= 2.73 kA, Iy= 2.143 kA, 135.2 km)

Neelamangala (KPTCL) end:

As per FIR/ DR/ EL/ TR line tripped at 04:06:33.612 hr. on operation of reactor protection (Ir -

Annexure-II


24.78 kA, Iy-25.27kA, Ib - 0.55 kA; 0.2 km). 400kV Hiriyur-Nelamangala line-1 reactor Y phase bushing failed triggering fire which caused line R and Y phase fault.

Tripping of 400kV Gooty – Neelamangala line: Gooty (PGCIL-Sr-1) end:

As per FIR line did not trip at Gooty end. Neelamangala (KPTCL) end:

As per FIR/ DR/ EL/ TR line tripped at 04:06 hr. on operation of DPR Reverse Zone.

Deliberations:

KPTCL vide mail dated 30.07.2019 informed that Y' phase bushing of 400kV Hiriyur-Nelamangala line-1 reactor failed followed with fire. This led to tripping of the line on operation of distance protection. Along with this, 400kV Nelamangala-Gooty line tripped at Nelamangala end due to suspected mal operation of Main-2 THR relay.

Remedial Measures Taken: KPTCL vide mail dated 30.07.2019 informed that action has been taken to replace the Main-2

THR relay at Neelamangala end by commissioning new CRP mounted in bay KIOSK under R&M works. Presently the work of Mysore-1 and Bidadi-1lines have been taken up. Cable laying work is under progress. After completing the above bays Gooty bay will be taken up.

Recommendations:

KPTCL is recommended to submit equipment failure report to CEA regarding the reactor bushing failure and also to sort out time synchronization issues of 400kV Hiriyur-Nelamangala line.

30 Tripping of 400/220kV ICT-1&2 at Munirabad substation

24-06-2019 at 20:50 hrs

400/220kV ICT-1&2 at Munirabad end got tripped due to operation of High set of backup earth fault relay during failure of Y phase CT in 220kV Munirabad-Kalyani steel feeder at Kalyani steel end

GI-2

Tripping of 220kV Munirabad – Kalyani steel line: Munirabad (PGCIL –SR-1) end:

As per FIR/ DR/ EL line tripped at 20:50:55.835 hr. on Y-B-E fault due to operation of DPR Z1 protection (13.6 kA). The Y-E fault was due to failure of Y-ph CT in 220kV Munirabad-Kalyani steel line at Kalyani steel end and B-E fault was due to failure of B-ph PT.

As per EL, LBB of 220kVMunirabad-Kalyani steel line operated at 20:50:55.924 but immediately it got reset.

Annexure-II


Tripping of 400/220kV ICT-1 at Munirabad:

As per FIR/ DR/ EL / TR ICT-1 tripped at 20:50:55.758 hr. on operation of High set back up E/F protection (5.2 kA).

Tripping of 400/220kV ICT-2 at Munirabad:

As per FIR/ DR/ EL / TR ICT-1 tripped at 20:50:55.734 hr. on operation of High set back up E/F protection (5.3 kA).

Remedial Measures Taken: KPTCL vide mail dated 30.07.2019 informed that 220kV Kalyani Steel line distance relay settings

have been reviewed and revised consequent to the tripping.

Recommendations: KPTCL is recommended to submit equipment failure report to CEA regarding the CT and PT

failure.

Annexure-II


31

Tripping of HVDC Talcher-Kolar Pole-1

31-05-2019at 18:30

hrs

Pole 1 tripped on Line fault. Pole-1 restarted three times and went into RVO mode. The fourth fault caused tripping of the pole. Pole-2 went to ground return mode. Remarks: SPS Trip Signal-1 and Trip Signal-2 operated at Kolar end since total power loss was ~1700 MW

Kolar (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR Pole-1 tripped at 18:30:22.418 hr. on operation of DC line differential Protection.

Annexure-II


Tripping of HVDC Talcher-Kolar Pole-1&2

05-06-2019 at 19:01 hrs

HVDC Talcher-Kolar Pole-1 tripped on receipt of ESOF (Emergency Switch On to Fault) signal at Kolar from Talcher end. Pole-2 went to metallic return mode with a power flow of 900MW at Kolar end. Subsequently at 19:02 Hrs, HVDC Talcher-Kolar Pole -2 also tripped due to operation of undervoltage protection at Kolar end. Remarks: After tripping of Pole-1 SPS Trip Signal-1 operated leading to total load relief of 700MW.

Tripping of HVDC Talcher-Kolar Pole-1 at 18:53 hr: Kolar (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR Pole-1 tripped at 18:53:23:471 hr. on operation of ESOF (Emergency switch off ) signal from Talcher end. Tripping of Pole-1 initiated TK SPS-1 leading to load relief of 700MW.

As per TR the 400kV converter transformer isolator (B-ph) had opened under load, following which the operator at Talcher had initiated manual ESOF.

Annexure-II


Tripping of HVDC Talcher-Kolar Pole-1 at 19:01 hr: Kolar (PGCIL-SR-2) end:

In the antecedent condition HVDC Pole-1 was out of service and Pole-2 was in Monopolar Metallic Return mode with a power of 900W.

As per FIR/ DR/ EL/ TR Pole-2 tripped at 19:01:50:242 hr. on operation of Undervoltage protection due to loss of incoming NTPC lines 1- 4.

Annexure-II



08-06-2019 at 12:10 hrs

Pole 1 tripped on receipt of ‘ESOF” from other side at 12:10 Hrs. Pole-2 shifted to metallic return mode of operation. Remarks: SPS Trip Signal-1 operated at Kolar end leading to total load relief of 700MW.

Annexure-II



As per FIR/ DR/ EL/ TR Pole-1 tripped at 12:10:07.856 hr. on operation of ESOF (Emergency switch off ) signal from Talcher end. Tripping of Pole-1 initiated TK SPS-1 leading to load relief of 700MW.


12-06-2019 at 12:24 hrs

While carrying out the switching operation of charger-2 to Charger-3 for enabling maintenance by OEM, Pole -2 got tripped due to suspected over voltage in 24V system. After tripping of Pole-2, Pole-1 continued to operate in metallic return mode Remarks: SPS at Kolar did not operate since total power loss after tripping of Pole-2 was less than 500 MW


As per FIR/ DR/ EL/ TR Pole-2 tripped at 12:24:05:397 hr. on operation of ESOF signal due to power supply fault in 24V DC system.

Annexure-II


Annexure-II


Remedial Measure Taken: PGCIL (SR-2) informed that the power supply fault was due to battery changeover switch

problem and the same will be rectified in next opportunity shutdown.

32

220kV Lower Sileru-KTPS line

01-06-2019 at 00:00 hrs

R-phase to ground fault. Auto-reclose was successful at Lower sileru end. A/r is not enabled at KTPS

GI-1

KTPS (TSGENCO) end:

As per FIR line tripped at 00 hr. on R-E fault due to operation of DPR Z1. (84.1 km)

As per DR/ EL/ TR line tripped at 13:28:07.947 hr. on R-E fault due to operation of DPR Z1. (84.1 km)

Lower Sileru (APGENCO) end:

As per FIR/ TR line tripped at 00 hr. on R-E fault due to operation of DPR Z1 and auto-reclosed.


02-06-2019 at 15:30 hrs

R-phase to earth fault occurred in line. Auto-reclose was successful at Lower sileru end. A/r is not enabled at KTPS.

GI-1

KTPS (TSGENCO) end:

As per FIR/ DR/ EL/ TR line tripped at 15:24:21.280 hr. on R-E fault due to operation of DPR Z1. (99.69 km)


As per FIR/ TR line auto-reclosed successfully on R-E fault due to operation of DPR Z1.


09-06-2019 at 11:58 hrs

B-phase to earth fault occurred in line. Zone-2 operated at KTPS and Earth fault at Lower sileru. Suspected high resistance fault.

GI-1

KTPS (TSGENCO) end:

As per FIR/ DR/ EL/ TR line tripped at 11:58:27.534 hr. on B-E fault due to operation of DPR Z2. (48.69 km; TZ2= 350msec)


As per FIR/ TR line tripped at 11:58 hr. on B-E fault due to operation of Directional E/F

Annexure-II


Protection.


12-06-2019 at 14:23 hrs

Y-phase to earth fault occurred in line. Auto-reclose was successful at Lower Sileru end. A/r is not enabled at KTPS

GI-1

KTPS (TSGENCO) end:

As per FIR/ DR/ EL/ TR line tripped at 14:23:07.593 hr. on Y-E fault due to operation of DPR Z1 protection. (84.18km)


As per FIR/ TR line tripped at 14:23hr. on Y-E fault due to operation of DPR Z1 Protection and auto-reclosed.

TSGENCO informed vide mail dated 30.09.2019 that in view of phasing out of the units, the implementation of the scheme in 220 KV generating stations is under discussions regarding relay settings & mapping

Recommendations: ATRANSCO in coordination with TSTRANSCO to ensure frequent patrolling and proper

maintenance of ROW by attending all tree clearance issues.

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

Sl. No. Element Date & Time Reason

1 Tripping of 400kV Ghani-Narnoor line-1

21-05-2019 at 15:11 hrs

B-phase to earth fault occurred in line. Auto-reclose was not successful as fault was persistent in nature. Fault was cleared in zone-2 time during A/r attempt

Ghani (APTRANSCO) end:

Asper FIR/ DR/ EL line tripped in 3-ph on B-E fault on operation of DPR Z1. Narnoor (APTRANSCO) end:

As per FIR/ DR/ EL line tripped in B-ph on B-E fault due to operation of DPR Z2 CAT protection and attempted A/R. (14.63kA; 16.86kA) But since the fault was persisting line tripped in 3-ph after auto-reclosure due to operation of SOTF operation. During SOTF operation since fault was detected in Z2 and no carrier was received from remote end line tripped after Z2 delay of 350msec.

Deliberations:

The reason for the tripping was B-E fault at 15:13:28 hr. on 400kV Ghani-Narnoor line-1. In antecedent condition at Ghani end Main CB was already open and Tie CB issued 3-ph trip (did not attempt A/R) on operation of distance protection Z1. Narnoor end attempted autoreclosure on operation of DPR Z2 CAT. But since the fault was persisting in nature subsequently tripped in 3-ph. But during 3-ph tripping since no carrier was received from Ghani end (since Ghani end already open) Narnoor end tripped with a Zone-2 delay of 350msec.

Recommendations: APTRANSCO is recommended to send a detailed report regarding non-availability of Main CB

(Main CB was already in tripped condition in antecedent condition) during the tripping and non-attempt of auto-reclosure by Tie CB at Ghani end.

Annexure-II


2 Tripping of 400 kV Kudgi PG (Narendra-New) - Tumkur line - 2

21-05-2019 at 15:30 hrs

Y-phase to earth fault occurred in line. Auto-reclose was successful at Tumkur. At Kudgi end Auto-reclose was not attempted

Narendra-New (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR line tripped in Y-ph at 15.30.03.360 hr. on Y-E fault due to operation of DPR Z2 CAT protection, but after 800msec tripped in 3-ph. [subsequentlyOVR appeared and line tripped at 15:30.08.141 hr. on OVR operation?]

Tumkur (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR line tripped in Y-ph on Y-E fault due to operation of DPR Z1 operation and auto-reclosed successfully. [121.6 km]

PGCIL (SR-2) informed that the delay in goose signal communication between Main-2 relay and BCU at Kudgi PG end led to the tripping of the line. Due to the delay, the same was understood as subsequent fault and relay issued 3-ph trip command.

3 Tripping of 400kV Talarichevu - Jamalamadugu ckt-1

21-05-2019 17:51 hrs

B -ph to ground fault in the line. Auto reclose operated at Talarichevu end but tripped on persistent fault. Auto reclose not attempted at Jamalamadugu end

Talarichevu (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped in B-ph at 17:59:55.960 hr. B-E fault due to operation of DPR Z1 operation and auto-reclosed. But subsequently line tripped in 3-ph on SOTF operation due to persisting fault.

Jamalamadugu (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped in B-ph at 17.59.52.449 hr. B-E fault due to operation of DPR Z1 operation but after 300msec tripped in 3-ph due to A/R configuration problem in BCU (15.7 km; 7.13 kA).

Remedial Measures Taken: APTRANSCO informed that non-attempt of A/R at Jamalamadugu SS was due to A/R

configuration problem in BCU and the same has been rectified.

4 Tripping of 400kV Talarichevu - Jamalamadugu ckt-1

22-05-2019 at 19:21 hrs

R phase to Earth fault in the line. At Jammalamadugu end A/r operated and line tripped due to persistent fault. Main CB A/r not attempted at Talarichevu

Talarichevu (APTRANSCO) end:

As per FIR/ DR/ EL line tripped in R-ph at 19:19:48.512 hr. on R-E fault due to operation of DPR Z1 operation. Main CB A/R not successful and it tripped in 3-ph after 500msec but Tie CB reclosed and tripped due to persisting fault.

Jamalamadugu (APTRANSCO) end:

As per FIR/ DR/ EL line tripped in R-ph at 19:46:03.161 hr. on R-E fault due to operation of DPR, Z1 and auto-reclosed but subsequently tripped in 3-ph due to persisting fault.

Recommendations:

APTRANSCO is recommended to submit a report regarding non-attempt of A/R by Main CB at Talarichevu end of 400kV Talarichevu - Jamalamadugu ckt-1.

e

Annexure-II


5 Tripping of 400 kV Kudgi PG (Narendra-New) –Tumkurline-2

23-05-2019 at 22:05 hrs

Y-phase to earth fault occurred in line. Auto-reclose was successful at Tumkur end. At Kudgi(PG) end A/r was not attempted due to A/r block

Kudgi PG(Narendra-New) (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR line tripped in Y-ph at 22:05:09.260 hr. on Y-E fault due to operation of DPR Z1. But immediately tripped in 3-ph (22:05:09.349 hr.) due to A/R lockout. After 4 secs, OVR Stg.-1 operated and sent DT to other end (Tov= 4 sec; Vr = 240.4 kV, Vy= 144.96kV, Vb=236.62 kV). [ Grading - I, 109%, 4sec]

Tumkur (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR line tripped in Y-ph at 22:05:09.352 hr. on Y-E fault and auto-reclosed successfully. Later line tripped in 3-ph on receipt of DT from Kudgi end.

OVR Grading 2018 for Kudgi PG:

PGCIL (SR-2) informed that the reason for non-attempt of A/R at Kudgi PG end was due to carrier fail alarm which issued A/R lockout.

Remedial Measures Taken: PGCIL (SR-2) informed that healthiness of carrier communication has been ensured after the

incidence.

6 400 KV Thiruvelam – Palavadi line-1

28-05-2019 at 18:04 hrs

B-phase to earth fault. A/r attempt could not be validated.

Thiruvalem (TANTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped in 3-ph at 18:02:45.019 hr. on receipt of DTT from other end. A/R started in B-ph for B-E fault on operation of DPR Z2 CAT (179.8 km, 3.168kA) but immediately line tripped in 3-ph due to DT receipt.

Palavadi (TANTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped in B-ph at 18:04:39.553 hr. on B-E fault but did not reclose and subsequently tripped in 3-ph.

TANTRANSCO informed that due to breaker unhealthy feedback (no spring charge due to station supply failure) 3 phase trip extended

TANTRANSCO informed that non-attempt of A/R at Palvadi end was due to failure of AC station supply.

Annexure-II


Recommendations: TANTRANSCO is recommended to check sending of DT from Palvadi end during 3-ph trip at

Palvadi. The time synchronization issues between Thiruvalem and Palvadi shall also be rectified.

7 Tripping of 400kV Pugalur-Karaikudi line-1

31-05-2019 at 17:44 hrs

R-phase to earth fault occurred in line. Auto-reclose was successful at Karaikudi, At Pugalur end there was 3-phase trip

Pugalur (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR line tripped in R-ph at 17:44:52.684 hr. on R-E fault due to operation of DPR Z1. A/R attempted but not successful and after 300msec line tripped in 3-ph.

PGCIL-SR-2 informed that A/R was unsuccessful due to low CB air pressure. Karaikudi (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR line tripped in R-ph at 17:44:42.369 hr. on R-E fault due to operation of DPR Z1 and auto-reclosed successfully (43.8 km).

Recommendations: PGCIL (SR-2) is recommended to ensure proper condition monitoring of their CB’s such as

sufficient air pressure.

8 Tripping of 400kV Ramagundam-Ghanapur line

02-06-2019 at 13:23 hrs

R-phase to earth fault occurred in line. Auto-reclose was successful at Ghanapur and A/r was not attempted at Ramagundam due to DT receive

Ramagundam (NTPC) end:

As per FIR/ DR/ EL/ TR line tripped in R-ph on R-E fault due to operation of DPR Z1. A/R started but unsuccessful due to receipt of DT at 13:24:31.473 hr. [PLCC DT increment indicated]

Ghanapur (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR line tripped in R-ph on R-E fault due to operation of DPR Z1 and autoreclosedsuccessfully.(3.03kA)[No PLCC DT increment]

Remedial Measures Taken: PGCIL (SR-1) vide mail dated 28.07.2019 informed that the fault was due to agrifire. Pamphlets

distributed to farmers and informed all locals not to put fire under the line. DT received at RDM end due to BPL make PLCC problems and same is being replaced with new PLCC panels at both ends. New PLCC panels received at site and will be commissioned by month end.

9 Tripping of 400kV Kalikiri-RYTPP line-2

02-06-2019 at 19:15 hrs

B-phase to earth fault occurred in line. Auto-reclose was successful at Kalikiri and A/r not attempted at RYTPP due to A/r lockout

Kalikiri (APTRANSCO ) end:

As per FIR/ DR/ EL/ TR line tripped in B-ph on B-E fault due to operation of DPR Z2 CAT and autoreclosed successfully ( 168 km).

RYTPP (APGENCO) end:

As per FIR/ DR/ EL/ TR line tripped in B-ph at 19:15:40;426 hr. on B-E fault due to operation of DPR Z1. A/R started but unsuccessful dueto A/R lockout signal after 400msec to A/R start.

APGENCO informed that the non-attempt of A/R at RYTPP was due to Goose signal problem. The goose communication hanged and BCU issued lockout due to non updating of CB status by BCU.


Annexure-II


APGENCO informed that BCU was restarted and goose communication issue was resolved.

10 Tripping of 400kV VTPS-SURYAPET line-1

02-06-2019 at 13:15 hrs

B-phase to earth fault occurred in line. Auto-reclose was successful at Suryapet end. 2nd fault during reclaim time resulted in three phase trip. At VTPS end A/r was not attempted

VTS – IV (APGENCO) end:

As per FIR/ DR/ EL/ TR line tripped in 3-ph on B-E fault due to operation of DPR Z1. A/R started but immediately line tripped in 3-ph.

Suryapet (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped in B-ph on B-E fault due to operation of DPR Z1 and autoreclosed successfully (3.7kA; 60.02 km). But subsequently line tripped due to second fault in reclaim time.

Remedial Measures Taken: APGENCO informed that A/R was unsuccessful at VTS-IV end due to problem with A/R logic. The

logic was modified on 24.06.2019 and A/R is put into service.

11 Tripping of 765 KV Kurnool - NPS line-1

02-06-2019 at 17:41 hrs

R-phase to earth fault occurred in line. A/r not attempted due to PLCC channel fail.

Kurnool PG (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR line tripped in 3-ph on R-E fault due to operation of DPR Z1. The fault was due to jumper dislocation near isolators due to heavy gale winds.A/R not attempted due to PLCC channel failure.


As per FIR/ DR/ EL/ TR line tripped in 3-ph on R-E fault due to operation of DPR Z2 (TZ2-0.5 sec). Line tripped in Z-2 time due to non-receipt of carrier due to PLCC channel failure.

Remedial Measures Taken: PGCIL (SR-1) vide mail dated 28.07.2019 informed that all jumper connections at Kurnool SS

checked and PLCC channel restored by adjusting the levels and line taken into service.

12 Tripping of 400KV-Maheshwaram PG-Mahbubnagar line-1

06-06-2019 at 19:18 hrs

Y phase to Earth fault in the line. A/r not operated at Mahbubnagar

Maheshwaram PG (PGCIL – SR-1) end:

As per FIR/ DR/ TR line tripped in Y phase on Y-E fault due to operation of DPR Z2 CAT and autoreclsoed successfully (117.8 km; 1.04 kA).

Mehaboobnagar (TSTRANSCO) end:

As per FIR/ DR line tripped in 3-ph on Y-E fault due to operation of DPR Z1 and did not attempt A/R.

TSTRANSCO informed that LC will be availed shortly to check non-attempt of A/R at Mehaboobnagar end.

Recommendations: TSTRANSCO is recommended to submit a report regarding non-attempt of A/R at

Annexure-II


Mehaboobnagar with Remedial measures taken.

13 Tripping of 400 kV JSW -Guttur line

08-06-2019 at 13:13hrs

B-phase to earth fault occurred in line. A/r was not successful as fault was persistent. A/r not attempted at Guttur.

JSWEL end:

As per FIR/ DR/ EL/ TR line tripped in Y phase at 12:58:51.492 hr. on Y-E fault due to operation of DPR Z2 CAT and autoreclsoed successfully. On reclosure since the fault was persisting in nature, line tripped in 3-ph at 12:58:53.082 hr. with Z2 time delay.

Guttur (KPTCL) end:

As per FIR/ DR/ EL/ TR line tripped in 3-ph on Y-E fault due to operation of DPR Z1 and did not attempt A/R.

KPTCL vide mail dated 30.07.2019 informed that Upon detailed investigation regarding A/R block, problem in Auto Reclosure Selector Switch was observed (for M-I selection). Now A/R priority switch is changed to M-II position and found to be working satisfactory. Action has already been taken to replace the AR priority switch.

Remedial Measures Taken: KPTCL informed that non-attempt of A/R at Guttur end was due to PLCC problem that issued

A/R block. The same has been attended and rectified.

14 Tripping of 400kV Kaiga-Guttur line-2

16-06-2019 at 19:20 hrs

R-phase to earth fault. Auto-reclose attempt at Guttur end was not successful as fault was persistent in nature. Attempt for A/r could not be established from Kaiga end EL

Kaiga (NPCIL) end: As per FIR/ EL/ TR line tripped in 3-ph at 02:53:09.667 hr. on R-E fault due to operation of DPR

Z1 protection. A/R was started but immediately Tie CB issued A/R lockout and tripped. Main CB tripped only after 2 sec i.e, may be due to PD operation.

Guttur (KPTCL) end: As per FIR/ DR/ EL/ TR line tripped in R-ph at 02:53:11.652 hr. on R-E fault due to operation of

DPR Z2 CAT protection. Line autoreclosed but subsequently tripped due to Dt receipt from Kaiga.

Remedial Measures Taken: KPTCL informed that the reason for persisting fault was Insulator flashed over at tower location

231. Line has been charged after attending the line fault.

Recommendations: NPCIL (KGS) is recommended to identify the issue related to unsuccessful A/R attempt of 400kV

Kaiga – Guttur line. It is recommended to check the healthiness of all breakers including breaker timing.

Time synchronization of DR and EL at Kaiga end shall be ensured.

Annexure-II


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

Sl. No. Element Date & Time Reason

1 Tripping of 400kV Julurupadu-Managuru line -2

20-05-2019 at 15:57 hrs

Line tripped at Julurupadu end only on direct trip receive

Julurupadu (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 15:57:50.167 hr. on receipt of DT. [D/T receipt in EL] Manuguru (TSGENCO) end:

As per FIR/ DR line was holding from Manuguru end. Remedial Measures Taken: TSGENCO vide mail dated 30.09.2019 informed that without any disturbance in the line, DT

signal was generated from FOTE panel(BTPS end) and sent to other end(Julurupadu end) . The panel was checked but no discrepancy was found. In order to avoid unnecessary trippings, a letter was addressed to M/s BHEL requesting to depute the service engineer from GE to check the healthiness and configuration of the newly commissioned FOTE panel at BTPS.

2 Tripping of 400kV Khammam-Mamidapally line-1

27-05-2019 at 18:16 hrs

Line tripped only at Mamidapally end due to suspected PLCC maloperation

Khammam (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR line was holding from Khammam end. [ PLCC D/T increment not indicated] Mamidapalli (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 18:16:22.374 hr. on receipt of DT . [D/T receipt signal in EL]

Recommendations: For the subject line, the following shall be carried out by TSTRANSCO in coordination with

PGCIL(SR-I): (i)End-to-end testing for DT/ permissive & other signals may be ensured by testing at both the ends. (ii)Healthiness of PLCC system components ( hardware and software) at both the ends shall be checked and faulty components shall be repaired/ replaced .

3 Tripping of 765 kV Raichur- Kurnool line- 2

02-06-2019 at 17:41 hrs

Line tripped on operation of Over voltage stage-1 at Kurnool end. Direct trip was not sent to Raichur due to failure of PLCC channel at Kurnool and line was holding from Raichur.

Raichur PG (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR line was holding from Raichur end. Kurnool (PGCIl-SR-1) end:

As per FIR/ DR/ EL/ TR line tripped at 17:41:16.686 hr. on operation of OVR stg.-1 and DT was sent to other end. Line tripped at Kurnool end only .DT not received at Raichur end due to failure of PLCC channel at Kurnool end.

Remedial Measures Taken: PGCIL(SR-1) informed vide mail dated 28.07.2019 that PLCC channel restored by adjusting the

levels and line taken into service.

Annexure-II


4

Tripping of 400kV Warangal-Bhoopalapalli line-1 &BoopalppalliChandlapur line-1

08-06-2019 at 1:35 hrs

400kV Warangal-Bhoopalapalli line-1 line tripped only at Boopalappalli end on OV st-1 protection operation and DT was not sent to Warangal end due to failure of both PLCC channels. 400kV BoopalppalliChandlapur line-1 tripped at Boopalpalli end due to DT Receive

Trippping of 400kV Warangal-Bhoopalapalli line-1: Warangal (PGCIL-SR-1) end:

As per FIR line was holding from Warangal end. Bhoopalapalli (TSGENCO) end:

As per FIR/ DR/ EL/ TR line tripped at 01:35:33.243 hr. on operation of OVR Stg.1 but DT was sent to remote end [PLCC D/T increment mentioned].

Trippping of 400kV Bhoopalapalli - Chandlapur line-1: Bhoopalapalli (TSGENCO) end:

As per FIR/ DR/ EL/ TR line tripped at 01:35:34.270 hr. on receipt of DT from other end. [ DT receipt signal in EL]

Chandlapur (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 01:35:34.279 hr. on operation of OVR Stg.1 and DT was sent to Bhoopalapalli end.

TSGENCO informed that Unit-2 (600MW) tripped on flame failure on 08/06/2019@01:34Hrs, then Warangal-2 feeder on overvoltage stage-1@01:35Hrs and Chandlapur-2 feeder tripped @ 1:35Hrs on DT CH-1/CH-2 received from Chandlapur. It is also observed that PLCC counter incremented in PLCC panel but PGCIL/Warangal end CB not tripped.

TSGENCO vide mail dated 30.07.2019 informed that TSGENCO is coordinating with TSTRANSCO for testing of End-to-End communication for DT/ permissive & other signals; checking of Healthiness of PLCC system components and also for replacing of faulty components.

Recommendations: For the subject line, the following shall be carried out by TSTRANSCO in coordination with

TSGENCO (i)End-to-end testing for DT/ permissive & other signals may be ensured by testing at both the ends. (ii)Healthiness of PLCC system components ( hardware and software) at both the ends shall be checked and faulty components shall be repaired/ replaced .

6 Tripping of 400kV Kayathar-Kanarpatty line-1 & 2

10-06-2019 at 12:22 hrs

Line-1 & 2 tripped at Kanarpatty end due to spurious DT sent from kayathar end. Feeder did not trip at Kayathar end

Kayathar (TANTRANSCO) end:

As per FIR/ DR/ TR line was holding from Kayathar end, but sent spurious DT to Kannarpatti end. [ PLCC DT increment indicated]

Kannarpatti (TANTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped on receipt of DT from other end. [ PLCC DT increment indicated]

Remedial Measures taken: TANTRANSCO informed that the spurious sending of DT was due to PLCC panel problem at

Kayathar (NSD570D). The same has been informed to OEM for Corrective measures.

Recommendations:

Annexure-II


TANTRANSCO is recommended to submit a report regarding the problem with PLCC panel at Kayathar along-with Remedial Measures suggested by OEM.

7 Tripping of 400kV Ramadugu-Singareni line

11-06-2019 at 08:24 hrs

Line tripped due to Direct Trip receive at Ramadugu end

Ramadugu (TSTRANSCO) end:

As per FIR/ DR/ EL line tripped at 08:24:53.669 hr. on receipt of DT from other end. [ PLCC DT increment indicated]

Singareni (STPP) end:

No tripping files furnished.

Recommendations: Singareni STPP is recommended to submit a detailed report regarding sending of DT from

singareni end that resulted in tripping of 400kV Ramadugu-Singareni line.

Annexure-II


1.1 The SLD of 220/ 110 kV Palakkad SS of KSEBL

Annexure-II


The SLD of 220/ 110 kV Pothencode SS of KSEBL

1.2 The SLD of 220/ 110 kV Pothencode SS of KSEBL

Annexure-II


1.3 The SLD of 220/ 110 kV Malaparamba SS of KSEBL

Annexure-II


1.4 The SLD of 220/ 110 kV Sedam SS of KPTCL

Annexure-II

85th PCSC meeting

31th July 2019

1

Annexure-III

Page 1 of 81

Details of Grid Disturbances

2

Annexure-III

Page 2 of 81

85.I.1. Complete outage of 220kV/110kV Palakkad Substation of KSEB on 04-06-2019 at 14:02 hrs

• Triggering Incident: Testing of Bus Coupler CT was being carried out duringwhich LBB trip got initiated and resulting in tripping of Bus-2.

• All elements were connected to Bus-2• Load Loss-268 MW

3

Double Main with Bus Coupler

Annexure-III

Page 3 of 81

PMU Plots

4

Remedial Actions Furnished

• Warning stickers were provided and other precautionary steps were taken to avoid similar incidents in future.

Bus DR: DR Trigger time-14:02:50.911 hrs

BC_TRIP

BUS1 BB OP

BUS2 BB OP

SCADA PlotDR

Annexure-III

Page 4 of 81

GD\1.1\PLKD SS\17353_SENDDR-PALAKKAD_DR.pdf

GD and GI\2.1\16770_SENDDR-400kV_ALAMATHY_ICT5_DR.pdf

85.I.2. Complete outage of 220kV Pothenkode Substation of KSEB on 04-07-2019 at 01:18 hrs

• Triggering Incident: Failure of suspension insulator (connecting to fly bus) of220kV Pothenkode – Trivendrum ckt-2

• Bus bar protection of Bus-1 and Bus -2 operated• Load Loss- 300MW

5

Annexure-III

Page 5 of 81

85.I.3. Complete outage of 220kV Malaparamba SS of KSEB on 29-05-2019 at 01:12 hrs

• Triggering Incident: R-phase to Earth fault in 220kV Malaparamba Areakodeline due to insulator decapping.

• 220kV Malaparamba Substation was being radially fed from 220kV Areakode• Load Loss-268 MW

6

Annexure-III

Page 6 of 81

DR Analysis

7

PMU Plots

220kV Malaparamba Areakode line

Malaparamba End Areakode End

DR Trigger Time: 01:12:02.376 hrs

Rph fault

R pole open

DR Trigger Time: non readable

Annexure-III

Page 7 of 81

Details of Grid Incidents

8

Annexure-III

Page 8 of 81

85.II.1. Tripping of 400/230kV MANALI ICT-3 on 13-05-2019 at 2:42 hrs

• During test charging of 110 kV Manali-ETPS -1 , line got tripped on the activation of Back

up relay and Distance relay failed to act.

• ICT-3 got tripped on the activation of HV REF protection.

• After 400ms, Earth wire of 110 kV Manali ETPS -1 got cut and fell on Y ph conductor of 110

kV Manali TPL line resulting in Y ph to Earth fault. 9

TN Reply

Annexure-III

Page 9 of 81

GI\2.1\TN Email Reply-2.pdf

10

DR Analysis

400/110 kV ICT-3 at Manali


HV REF operated

110 kV Manali ETPS -1

Manali ETPSDR Trigger Time: 02:42:54.510hrs

Distance Forward Pickup

IfaultR=7.34kA

IfaultY=7.298kA

IfaultB=7.421kA

Fault current persistent for 1.1sec

3ph trip

Digital signals in DR are not mapped properly.

DR Trigger Time: 02:42:54.509hrs


After 1.1 sec 50/51 operated

DR Trigger Time:NA

ETPS end was in open condition.

110 kV Manali TPL

Manali TPLDR Trigger Time: 02:45:56.045hrs

YN fault (Ifault Y=8.404kA)

Carrier Sent


3ph Trip

DR Trigger Time: NA

Line is radial

DR

DR

DR

DR

Annexure-III

Page 10 of 81

GI\2.1\110kV MNLI ETPS DR.JPG


GI\2.1\17144_SENDDR-400kV_ICT.3_REF_DR.pdf


GI\2.1\110kV MNLI TPL DR.JPG


GI\2.1\110kV MNLI ETPS DR_OCRelay.JPG


PMU Plots

First fault was cleared in 1160ms and

the Second fault got cleared in 80ms.

Points for Review

(1). Non operation of SOTF-distance protection of 110 kV Manali ETPS -1 at

Manali end.

(2). Tripping of 400/110 kV ICT-3 at Manali on REF protection during fault in

110kV line.

(3). 110kV line DR labelling is not proper.

11

Annexure-III

Page 11 of 81

85.II.2. Tripping of 400kV Madurai-Udumalpet line on 16-05-2019 at 18:54 hrs

• 400kV Udumalpet Madurai line tripped only at Udumalpet end on line

under frequency protection operation.

• Suspected R-ph CVT problem.

• Findings and Remedial actions taken shall be furnished.

12

Annexure-III

Page 12 of 81

85.II.3. Tripping of 400kV Kurnool-Srisailam line on 17-05-2019 at 14:10 hrs

• Triggering incident: Y phase to B phase fault in 220kV Narnoor Somayajulapalli line-1.

• 400kV Kurnool Srisailam line tripped only at Srisailam end on Zone-3 distance protection

operation.

TSGENCO reply to SRLDC Email

Points for Review

• Zone-3 distance protection operation at Srisailam without time delay

Annexure-III

Page 13 of 81

GI\1\16564_SENDDR-VELTOOR_URVAKONDA_LINE_1_DR 04-12-18.pdf

PMU Plots

220kV Narnoor Somayajulapalli line-1.Narnoor End Somayajulapalli End

Line was under idle charged condition from

Somayajulapalli end during antecedent


YN fault

Zone-1DR

400kV Kurnool-Srisailam line.Kurnool End Srisailam End

Line didn’t trip at Kurnool end DR Trigger Time: DR not Furnished. Zone-3

distance operation observed from EL.

14

EL

Annexure-III

Page 14 of 81

GI\2.3\REL670-3_DR of 220kV SYpalli Narnoor line-1 main-2.pdf

GI\2.3\17154_RENDDR-SRISAILAM_NARNOOR_Line_DR.pdf

85.II.4. Tripping of 220kV Ambewadi-Ponda line on 18-05-2019 at 12:13 hrs

• Triggering incident: BN Fault in the line.

• Line tripped on Zone 3 distance protection operation at Ambewadi end

PMU Plots

15

DR EL Remedial Actions Furnished by KPTCL

The healthiness of Siemens make new Main-II relay is checked once again after the incident and the relay is found to be working satisfactory for all fault conditions.

M-I relay which picked up when B phase voltage dipped to 106kV, fault current 70A IN reached 335A dropped out after 120msec

Annexure-III

Page 15 of 81

GI\2.4\17160_SENDDR-AP1_180519_DR.pdf

GI\2.4\17160_SENDEL-AP1_18-05-19-EL_compressed.pdf

85.II.5. Tripping of 400kV/220kV Neelamangala ICT#3 on 19-05-2019 at 16:10hrs and complete loss of 220kV Anchepalya and 220kV Magadi SS of

KPTCL on 19-05-2019 at 16:33hrs

• Triggering incident: BN fault in 220kV Neelamangala DB Pura line-1 and 2 at 16:10hrs due

to snapping of the earth wire during heavy rain.

• ICT-3 got tripped on operation of HV side High Set Over current trip

• 220kV Neelamangala Magadi line tripped on SOTF due to subsequent fault

• At 16:31hrs, 220kV Neelamanagala Anchepalya tripped at Neelamangala end on SOTF due

to BN fault.

• Load loss-80MW 16

Annexure-III

Page 16 of 81

17

220 kV DBPura Neelamangala-1

Tripping at 16:10hrs:

220kV Neelamangala End 220kV DBPura End


BN fault

280ms delay

SOF

86 operated

DR NA

220 kV DBPura Neelamangala-2

220kV Neelamangala End 220kV DBPura End


BN fault

100ms current persistent

240ms breaker opening

86 operated

DR NA

220 kV Magadi Neelamangala

220kV Neelamangala End 220kV Magadi End


BN fault

Ibfault=2.53A (Secondary current)

80ms delay

SOF

86 operated

DR NA

400/220 kV ICT-3 at Neelamangala


BN fault

Ibfault=3.07A (Secondary current)

132ms delay

HS OC/EF

DR is not time synchronised with GPS

Tripping at 16:31hrs:

220 kV Anchepalya Neelamangala

220kV Neelamangala End 220kV Anchepalya End


BN fault

80ms delay

SOF

86 operated

DR NA

DR

DR

DR

DR

DR

Annexure-III

Page 17 of 81

GI\2.5\Neelamangala End DR_DB Pura line-1.JPG

GI\2.5\Neelamangala End DR_Magadi line.JPG

GI\2.5\Neelamangala End DR_Anchepalya line.JPG

GI\2.5\Neelamangala End DR_DB Pura line-2.JPG

GI\2.5\Neelamangala ICT3 DR.JPG

18

PMU Plots

Points for Review:

Remedial Actions Furnished:

(1). High set element of 400kV/220kV ICT- 3 at

Neelamangala will be increased to 5A with time delay of

100ms.

(2). For 220kV lines, SOTF overcurrent pickup will be revised

to 8kA from 2kA to avoid undesired tripping.

(1). Reason for delayed fault clearance.(2). Tripping of 400kV/220kV ICT- 3 at Neelamangala for a through line fault.(3). Status of A/r for 220kV Neelamangala connected lines.(4). Tripping of 220kV Neelamangala lines on SOTF operation

Annexure-III

Page 18 of 81

85.II.6. Tripping of 400kV Ghani Narnoor line-1 and 400/220 kV ICT-2 at Ghani on 21-05-2019 at 15:13hrs

• Triggering Incident: BN fault in 400kV Ghani-Narnoor line-1

• ICT#2 tripped on LV Earth fault protection.

19

DR Analysis

400kV /220 kV ICT-2 at GhaniDR Trigger Time: 15:13:28.624 hrs

IN1>1 Start

IN1>1 TripDR

Time of operation

Annexure-III

Page 19 of 81

GI\2.6\ICT-2\17180_SENDDR-21.05.19 15.13.28 67IV DR.pdf

DR Analysis

Points for Review:

20

400kV Ghani Narnoor line-1

Ghani End Narnoor End


Zone-1 Trip

Carrier sent

A/r not attempted. All 3 phases tie

breakers got opened.


Zone 2

Carrier Receive

A/r operated

Zone-2 start

SOTF Trip Zone-2

Current persistent for around 250ms.

Remarks:

Status of main breakers at Ghani

end needs review

Status of tie breakers at Narnoor

end needs review

(1). Non operation of A/r at Ghani end for 400kV Ghani Narnoor line-1.

(2). Tripping of ICT on LV Earth fault protection during line fault.

(3). Opening of tie breaker before main breaker at Narnoor end during A/r.

PMU Plots

DR

DR

Annexure-III

Page 20 of 81

GI\2.6\ghani-narnoor\17173_SENDDR-21.05.19 15.13.28 M1.pdf

GI\2.6\ghani-narnoor\17173_RENDDR-21.05.19.15.13 GHANI1M1.pdf

85.II.7. Tripping of 400/220 kV ICT-3 at Mamidapalli on 21-05-2019 at 20:43 hrs

• ICT tripped on PRV-1 indications due to ingress of moisture into the

relay.

• Findings and remedial actions taken shall be furnished.

21

Annexure-III

Page 21 of 81

85.II.8. Tripping of 765/400kV ICT-1 and 2 at Kurnool substation on 21-05-2019 at 18:11 hrs

• Triggering incident : During test charging of 400KV Kurnool-Nanoor line 1

ICT 1 and 2 got tripped due to maloperation of Bucholz relays.

• Line tripped on SOTF.

765/400kV ICT-1 at Kurnool


BCZ_ TR_Y, Three phase Group A and B

operated

DR

22

765/400kV ICT-2 at Kurnool


Digital signals not available

DR

• Remedial Actions: Informed OEM for corrective action

Annexure-III

Page 22 of 81

GI\2.8\ICT-1\17178_SENDDR-DR.pdf

GD and GI\2.8\16816_SENDDR-400kV_SPDR_ICT.2_ DR.pdf

GI\2.8\ICT-2\17179_SENDDR-DR.pdf

GD and GI\2.8\16816_SENDDR-400kV_SPDR_ICT.2_ DR.pdf

85.II.9. Tripping of 220KV Sabarigiri-Theni line on 23-05-2019 at 16:12 hrs

• Triggering incident: RN fault in the line

• Line tripped on operation of DEF at Theni end

• At Sabarigi end, distance protection operated

Observations from DR

Sabarigiri End Theni End


21 distance fwd pickup

Trip in 625ms, Fault distance=100KM


IN>1 Start

IN>1 Trip

DR

DR

Points for Review

23

• What protection operated at Sabarigiri end?

• Tree clearance issues?

Line length=107KM

Annexure-III

Page 23 of 81

GI\2.9\17186_SENDDR-230kV_THENI_MOOZIYAR_ FEEDER_DR.pdf

GI\2.9\17186_RENDDR-DR-230kV Theni-Mooziyar.pdf

85.II.10. Tripping of 400kV Sigareni-Sundilla line-2 on 24-05-2019 at 18:21 hrs

• Line tripped to operation of OV Stg-1

protection operation at Sundila end

• DT received at Singareni end.

• Difference in phase voltages observed

at Sundilla end.

24


Sigareni End Sundilla End


DT Receive


Vr-262kV, Vy-240kV and Vb-214kV

OV St-1 Start

OV St-1 Trip -observed from EL

DR DR

DR in cfg and dat

Annexure-III

Page 24 of 81

GI\2.10\17187_SENDDR-SINGARENI_SUNDILLA_LINE_2_DR 24-05-19.pdf

GI\2.10\17187_RENDDR-SUNDILLA_SINGARENI_LINE_2_DR 24-05-19.pdf

GD and GI\2.9\16834_RENDDR-NAR_GTR_LINE1_DR.pdf

85.II.11. Tripping of 400kV Hoody-Yelahanka line-1 on 25-05-2019 at 20:41 hrs

• Line tripped at Hoody end only and was holding from Yelahanka.

• No fault was observed from DR

25


Hoody End Yelahanka End


Dist fwd

Z1

SOTF Enable

SOTF/TOR Trip

All pole dead

DR Trigger Time: NA

Line didn’t trip at Yelahanka end

DR

Type of Main-1 and 2 . DR of other main

Annexure-III

Page 25 of 81

GI\2.11\17189_SENDDR-YELAHANKA DR MAIN I 25.05.19.pdf

85.II.12. Tripping of 400/220 kV ICT-1 at Guttur on 26-05-2019 at 10:00 hrs

• LV side of 400kV/220kV 315MVA ICT#1 Guttur got tripped due to CB

lockout (B phase)because of low SF6 gas in the CB

• Findings and remedial actions taken may be furnished.

• Similar incident happened on 13-May-2019 at 00:51hrs

26

Extracts from Minutes of 84th PCSC held on 27-06-2019

Annexure-III

Page 26 of 81

85.II.13. Tripping of 400kV NPS Nellore line-1 & 2 on 27-05-2019 at 17:42 hrs

• 400kV NPS Nellore-PG line-2 tripped at NPS end due to suspected maloperationof group B protection

• DT was sent to Nellore-PG end. • 400kV NPS Nellore-PG line-1 got tripped due to operation of SPS.

• Antecedent Flow=1100MW each

27

Implemented SPS logic:• In case of tripping of one 400kV Nellore – Nellore PS line and loading on other circuit:

• Recommended setting is 105 % of 2524Amp =2652 Amp

• (In steps of 10 A) Setting is = 2650 Amp and Time Delay=5 sec

Remedial action taken: 86 B trip relay replaced with spare relay and line taken into service.

Annexure-III

Page 27 of 81

85.II.14. Tripping of 230kV Theni-Sabarigiri line on 29-05-2019 at 18:39 hrs

• Triggering Incident: 3 phase to earth fault occurred in line.

• Zone-2 at Theni end.

28

220kV Sabarigiri Edamon-2 and 3 were under outage during antecedent.


Sabarigiri End Theni End


Distance Fwd

Relay Trip


Distance Fwd

Zone 2, Fault distance=97.44KM

DR DR

Points for Review

• Tree clearance issues?

Line length=107KM

Annexure-III

Page 28 of 81

GI\2.14\17232_SENDDR-230kV_THENI_MOOZHIYAR_ FEEDER_DR.pdf

GI\2.14\17232_RENDDR-220KV THENI_MOOZHIYAR_DR.pdf

85.II.15. Tripping of 400/220 kV ICT-1 and 400kV RTPS-RAICHUR PG line-2 on 29-05-2019 at 12:43 hrs

• Due to spurious operation of Tie breaker LBB at , 400/220 kV ICT-1 and

400kV RTPS-Raichur PG 2 got tripped at RTPS end and DT was sent to

Raichur PG end

29

Points for Review

Spurious operation of Tie breaker LBB

Annexure-III

Page 29 of 81

85.II.16. Tripping of 400kV Tumkur-Bidadi line-1&2, 400kV Tumkur-Cuddapahline-2, 400kV Tumkur-Pavagada line-2 on 29-05-2019 at 6:11 hrs

• Triggering incident: B phase LA failure at Tumkur end of 400kV Tumkur-Pavagada line-2 .

• 400kV Tumkur-Bidadi line-1&2 also got tripped.

• YN fault occurred at 6:11:02 hrs in 400kV Tumkur-Cuddapah line.

• A/r attempt was not successful as fault was persistent in nature.30

Annexure-III

Page 30 of 81

31


Tumkur End Cuddapah End


Zone-1, YN fault

Carrier sent

A/r operated, TOR


Zone 2, Carrier receive

A/r operated, SOTF/TORDRDR

400kV Tumkur-Cuddapah line-2

400kV Tumkur-Pavagada line-2

Tumkur End Pavagada End


Zone-1, YBN fault

Carrier sent


Zone 2, Carrier receive

DR DR

400kV Tumkur-Bidadi line-1

Tumkur End Bidadi End

DR Trigger Time: NA

Line didn’t trip at Tumkur end


Zone 2 start, Carrier receive

3 ph trip DR

Annexure-III

Page 31 of 81

GI\2.16\tmkr-cudapah\17231_SENDDR-TMK_KDPA_LINE2_DR.pdf

GI\2.16\tmkr-cudapah\17231_RENDDR-KDP-MDG-2_290519_0611Hrs_DR.pdf

GI\2.16\17230_RENDDR-TMK_PAV_LINE2_DR.pdf

GI\2.16\tumkr-pavgd\17230_SENDDR-PAV_TMK_LINE2_DR.pdf

GI\2.16\tumkur-bidadi\17228_RENDDR-BDD_TMK_LINE1_DR.pdf

32

PMU plots

400kV Tumkur-Bidadi line-2

Tumkur End Bidadi End


M2 trip

M2 operated


Zone 2 start, Carrier receive

Carrier receiveDR DR

Points for Review

• Tripping of 400kV Tumkur-Bidadi line-1&2

Annexure-III

Page 32 of 81

GI\2.16\tumkur-bidadi-2\17229_SENDDR-TMK_BDD_LINE2_DR.pdf

GI\2.16\tumkur-bidadi-2\17229_RENDDR-BDD_TMK_LINE2_DR.pdf

85.II.17. Tripping of 400 kV Ghani – Narnoor line-1, 400 KV Jamalamadugu-Kurnool line-1, 765/400 kV ICT-1&2 at Kurnool on 30-05-2019 at 00:48 hrs

• Triggering incident: Y-ph to B-ph fault in the 400kV Narnoor Jammalamadugu line-1& 2 due to falling of Y-ph CVT jumper on B-ph during heavy wind.

• 765/400 kV ICT-1 and 2 at Kurnool PG also got tripped on HV side DirectionalOvercurrent (DOC)

• 400kV Ghani Narnoor tripped only at Ghani end on operation of Zone-1 33

Annexure-III

Page 33 of 81

34


PMU Plots

400kV Narnoor Jammalamadugu-1

Narnoor End Jammalamadugu End

DR Trigger Time: 00.48.13.000.000 hrs

Y-ph to B-ph fault

I(y-ph)=15.41kA, I(b-ph)=15.40kA

Zone-1

Carrier sent

86 operated


Y-ph to B-ph fault

Zone 2 Pickup

86 operated

From EL:

CARRIER RECEIVED CH-2 at 00:48:13.077 hrs

DR DR

Annexure-III

Page 34 of 81

GI\2.17\narnoor-jmldg\17242_SENDDR-401 NANNUR-1 M1 DR.pdf

GI\2.17\narnoor-jmldg\17242_RENDDR-300519 00_48 JMD1 DRM2.pdf

35


400kV Narnoor Jammalamadugu-2

Narnoor End Jammalamadugu End (Main-1 and Main-2)


Y-ph to B-ph fault

I(y-ph)=29.7kA, I(b-ph)=30.05kA

Zone-1

Carrier sent

86 operated

DR Trigger Time:

00:47:55.450 hrs

Distance pickup

DT Receive

86 operated

DR Trigger Time:

00:47:55.903 hrs

Zone 2 Pickup

Carrier Receive

86 operated

From EL:

CARRIER RECEIVED CH-2 at 00:47:55.937 hrs

DT RECEIVED CH-2 at 00:47:55.968 hrs

400kV Narnoor Ghani-1

Narnoor End Ghani End

Line didn’t trip at Narnoor end DR Trigger Time: 00:48:13.083 hrs

Zone 2 Pickup

86 operated

From EL:

21M2_PROT,ZONE-1 PROTECTION,OPERATED at

00:48:13.071hrs

DR

DR

DR DR

Annexure-III

Page 35 of 81

GI\2.17\narnoor-jmdg-2\17243_SENDDR-404 NANNUR-2 M1 DR.pdf

GI\2.17\Ghani - Narnoor\17255_SENDDR-Ghani-NNR-1-21M1-30.05.19- 00_48_13 DR.pdf

GI\2.17\narnoor-jmdg-2\17243_RENDDR-30.05.19 00.47.55 JMD2.pdf

GI\2.17\Jammalamadugu Main 2 DR.JPG

36


765/400 kV ICT-1 at Kurnool PG


Y-ph to B-ph fault

I(y-ph)=2.26kA, I(b-ph)=3.83kA

HV side DoC operated



Y-ph to B-ph fault

I(y-ph)=2.3kA, I(b-ph)=3.89kA

HV side DoC operated

Points for Review

(1). Tripping of 400kV Narnoor Ghani line at Ghani end.

(2). Tripping of 765/400 kV ICT-1 and 2 at Kurnool PG for a through line fault.

DR DR

Annexure-III

Page 36 of 81

GI\2.17\ICt-1\17246_SENDDR-KLN_ICT-1_300519_0047Hrs_DR.pdf

GI\2.17\ICt-2\17245_SENDDR-KLN_ICT-2_300519_0047Hrs_DR.pdf

85.II.18. Tripping of 765/400kV ICT-2 at Kurnool on 02-06-2019 at 17:41 hrs

• Triggering Incident: RN fault in 765kV Kurnool NPS-1

• YN fault in 765kV Kurnool Raichur-1

• ICT-2 got tripped on operation of HV side high set directional over

current during through fault (R-Y phase fault).

37

Annexure-III

Page 37 of 81

38



R-ph fault, subsequent Y-ph fault

HV side high set DoC operated


765kV Kurnool NPS-1

Kurnool End NPS End


R phase fault (Ifault=10.8kA)

Zone-1, Carrier sent

A/r not operated


R phase fault (Ifault=1.73kA)

Zone-2

Carrier not received

765kV Kurnool Raichur-1

Kurnool End Raichur End


Y phase fault(Ifault=4.4927 kA)

Zone 2, carrier receive

A/r operated

After 2s, B phase fault(Ifault=4.3014 kA)

3 phase trip


Y phase fault

Zone 1, carrier sent

A/r operated

After 2s, B phase fault

3 phase trip

DR

DR DR

DR

DR

Annexure-III

Page 38 of 81

GI\2.18\kurnool raichur\17280_SENDDR-400kV_Raichur_Kurnool_Line1_DR-02062019.pdf

GI\2.18\kurnool nps\17275_SENDDR-KLN-NPS-1_020619_1741Hrs_DR.pdf

GI\2.18\kurnool nps\17275_RENDDR-KLN-NPS-1_020619_1741Hrs_DR.pdf

GI\2.18\kurnool raichur\17280_RENDDR-400kV_Kurnool_Raichur_Line1_DR.pdf

GI\2.18\17283_SENDDR-765kV_Kurnool_ICT2_DR-02062019.pdf

39

PMU Plots

Points for Review

(1). Tripping of 765/400 kV ICT-1 at Kurnool PG for a through line fault(2). Non operation of A/r at Kurnool end for 765kV Kurnool NPS line-1(3). Failure of carrier aided protection at NPS end for 765kV Kurnool NPS line-1

Annexure-III

Page 39 of 81

85.II.19. Tripping of JSW-Guttur line on 02-06-2019 at 18:17 hrs

• Line tripped due to OV St-1 protection operation at JSW end

• DT was sent to Guttur end.

• At JSW end, B ph voltage was observed to be lesser comparing to R ph

and Y ph.


JSW End Guttur End

Trigger time-18:16:19.204 hrs

OV st-1 Trip

(Vr-249kV, Vy-255kV and Vb-230kV)

Trigger time-18:09:52.544 hrs

DT Receive

251kV , 245kV and 245kV

DR not time synchronised with GPSDR

DR

40

Remedial Actions Furnished by KPTCL:

The suspected R phase CVT has been replaced by new CVT on 25.07.2019

Annexure-III

Page 40 of 81

GI\2.19\17284_SENDDR-JSW_GUTTUR_LINE2_DR.pdf

GI\2.19\17284_RENDDR-400KV JSWEL GUTTUR 02.06.19 at 18.17Hrs.pdf

85.II.20. Tripping of 220kV Idukki-Udumalpet line on 05-06-2019 at 15:13 hrs

• Triggering incident: R-Y-Earth fault in the line.• Carrier aided protection not operated at Udumalpet end.

41

Observations from DRIdukki End Udumalpet End


R-Y-Earth fault

Zone-1

Carrier sent

DR Trigger Time:15:06:37.563 hrs

R-Y-Earth fault

(Ifault=2.8kA, 3.1kA)

Zone-2

DR DR

PMU Plot

Annexure-III

Page 41 of 81

GI\2.20\17305_SENDDR-220KV IDUKKI-UDUMALPET.pdf

GI\2.20\17305_RENDDR-230kV_UDUMELPET_IDUKKI FEEDER_ DR.pdf

85.II.21. Tripping of 400kV JSW -Guttur line and 400 kV Kaiga - Guttur line-2 on 05-06-2019 at 18:27 hrs

• Triggering Incident: Y-phase to earth fault occurred in 400kV Kaiga-

Guttur line-2.

• A/r was successful at Guttur end.

• At Kaiga end A/r was not attempted and breakers got tripped due to

operation of Pole discrepancy (1.65 Sec).

• 400kV JSW-Guttur line tripped on operation of over-voltage at Guttur

and DT received at JSW.42

Annexure-III

Page 42 of 81


Kaiga End Guttur End


YN fault

Zone-1

Y ph open at 40ms. B ph opened at 100ms. R pole

open at 1700ms.


YN fault(Ifault=6.081kA)

Zone-1

A/r operated successfully

DR DR

Points for Review

• Non successful operation of A/r at Kaiga end.

• From DR of Guttur, it is observed that there was swell in R & Y phase voltage for

few cycles43

400 kV Kaiga - Guttur line-2

400kV JSW-Guttur line

JSW End Guttur End


DT Receive



OV st-1 pickup

Vr-259kV, Vy-152kV and Vb-254kVDR DR

Annexure-III

Page 43 of 81

GI\2.21\kaiga-guttur\17315_SENDDR-KAIGA_GUTTUR_LINE2_DR.pdf

GI\2.21\kaiga-guttur\17315_RENDDR-Kaiga-2 05.06.19 at 18.27hrs.pdf

GI\2.21\jsel-guttur\17310_SENDDR-JSW_GUTTUR_LINE_2_DR.pdf

GI\2.21\jsel-guttur\17310_RENDDR-JSWEL Main-2 DR 05.06.19 18.27.pdf

44

Observations from Kaiga EL

• Fault was sensed in Zone-1 (18:27:05.295 hrs-from EL)• At 18:27:05.298 hrs (from EL), Y phase protection• At 18:27:05.397 hrs (from EL), B phase Breaker open• At 18:27:06.951 hrs(from EL), Pole discrepancy of CB02B operated (Suspected non-opening of R-

ph breaker-from DR)• At 18:27:11.488 hrs (from EL), OV relay operated

PMU Plots


The suspected R phase CVT has been replaced by new CVT on 25.07.2019

Annexure-III

Page 44 of 81

45

Extracts from Minutes of 83rd PCSC held on 16.05.2019

Annexure-III

Page 45 of 81


Kaiga End Guttur End

DR Trigger: 01:49:21.620 hrs

Z1 operated, R-ph fault

A/r operated

After 300ms subsequent fault occurred

LBB operated, DT sent

DR Trigger: 01:49:21.625 hrs

R ph fault, Z2 operated, CAT

A/r operated

DT Received

DR

Observations from Kaiga EL

• Fault was sensed in Zone-1 (01:49:19.576 hrs-from EL)• LBB of main breaker(CB02B) of the line operated due to struck breaker condition(01:49:19.817 hrs-

from EL) of B-ph• At 01:49:21.285 hrs(from EL), Pole discrepancy of CB02B operated (Suspected non-opening of B-ph

breaker-from DR)

Annexure-III

Page 46 of 81

GI\2.21\2.10_old\16821_SENDDR-KAIGA_GUTTUR_LINE_2_DR.pdf

Extracts from Minutes of 82nd PCSC held on 28.03.2019

Annexure-III

Page 47 of 81

85.II.22. Tripping of 400kV Dhoni-Munirabad line on 06-06-2019 at 02:01 hrs

• Line got tripped at Dhoni end.

• From DR Zone-3 start, PSB and A/r block

was observed.

48


Dhoni End Munirabad End

Main-1

DR Trigger Time:

02:00:57.884 hrs

Relay pickup

Main-2


Relay pickup


Tie breakers open

Line didn’t trip at Munirabad end

EL

400 kV Dhoni - Munirabad line-2

DR

Dhoni end DR digital signal labelling is not proper

400kV Guttur-Narendra ine-1&2 got tripped due to collapse of 04 nostowers resulting in a R-Y phase to earth fault.

DRDR

Annexure-III

Page 48 of 81

GI\2.22\Dhoni- Mnrbd\17338_SENDEL-PSB.pdf

GI\2.22\Dhoni end M2 DR1.JPG



49

PMU Plot

• PSB mal operation is suspected in Main-I Siemens relay.• The issue is referred to the OEM.


Annexure-III

Page 49 of 81

NP Kunta End Hindupur End


Zone-1.

Main CB R, Y & B poles got tripped

Tie CB R-pole tripped which was followed by tripping

of Y and B pole (260ms later) due to operation of

over-voltage Stg-2 protection

Vr-462kV


Carrier receive

OV St-2

DT Send

85.II.23. Tripping of 400kV N.P.Kunta-Hindpur line-2 on 09-06-2019 at 18:14 hrs

• Triggering incident: R-phase to

earth fault occurred in line

• Line tripped due to operation

of over-voltage stg-2.

DR

50

Line reactor is at Hindupur end

PSCAD Study Results

DR

Annexure-III

Page 50 of 81

GI\2.23\17328_SENDDR-400kV_NPKunta_Hindupur_line2_DR-09062019.pdf

GI\2.23\plots.pdf

GI\2.23\17328_RENDDR-09.06.2019 Hindupur NPkunta-2 DR.pdf

85.II.24. Tripping of 400kV Vemagiri-Vijayawada line-3 on 10-06-2019 at 9:18 hrs

• Line tripped due to maloperation of Line Reactor Differential relay at

Vijayawada end

• DT was received at Vemagiri end.

51

Vemagiri End Vijayawada End


DT Receive


Tie and Main breakers open

From EL, LR operation permitted


ELDR

Remedial Actions Furnished by PGCIL: Line Reactor differential relay found faulty and relay taken out of service, line charged. Faulty L/R differential relay at Vijayawada end replaced with MiCOM-P643 relay.

Annexure-III

Page 51 of 81

GI\2.24\17337_RENDEL-400kV_Vemagiri_-Vijayawada_Line3_EL-10062019.pdf

GI\2.24\17337_RENDDR-400kV_-Vijayawada_Vemagiri_Line3_DR-10062019.pdf

85.II.25. Multiple Tripping in 400kV Julurupadusubstation on 10-06-2019 at 8:22 hrs

• Triggering incident:

• 400kV lines tripped due to operation of over-voltage stg-1.

• 400/220kV ICT-1&2 at Julurupadu on operation of over flux protection.

52

Annexure-III

Page 52 of 81

53

KTPS-VII End Julurupadu End


OV St-1 operated


Trip Bus-1

DT Receive


400kV KTPS-VII - Julurupadu Line-2.

400kV Julurpadu - Suryapet Line-1.

Julurpadu End Suryapet End


OV St-1 operated


DR Not submitted

DR DR

DR

Annexure-III

Page 53 of 81

GI\2.25\ktps-jlrpd-2\17331_SENDDR-D60-DR.pdf

GI\2.25\ktps-jlrpd-2\17331_RENDDR-JULURUPADU_KTPSVII_LINE_2_DR 10-06-19.pdf

GI\2.25\surypet-jlrpd\17335_RENDDR-JULURUPADU_SURYAPET_LINE_1_DR 10-06-19.pdf

54

Julurpadu End


V/f operated

Group B operated


400kV/220kV Julurpadu-ICT-1.

400kV/220kV Julurpadu-ICT-2

Julurpadu End


V/f operated

Group B operatedDR

DR

SCADA Plot

DR

Annexure-III

Page 54 of 81

GI\2.25\ICT-2\17334_SENDDR-JULURUPADU_ICT_2_DR 10-06-19.pdf

Raichur Solapur\17042_SENDDR-DR1.pdf

GI\2.25\ICT-1\17332_SENDDR-JULURUPADU_ICT_1_DR 10-06-19.pdf

85.II.26. Tripping of 220kV Sedam-RTPS line-1&2 and 220kV Sedam-Tandur line on 14-06-2019 at 02:00 hrs

• Triggering incident: R phase to Earth fault in 220kV Sedam RTPS line-2.

• At Sedam end, breaker didn’t open

• Fault was cleared by tripping of remote end feeders.

55

Annexure-III

Page 55 of 81

Observations from DR:

220kV Sedam RTPS line-1

Sedam End RTPS End

DR Trigger time: NA

DR and EL not submitted.

Line didn’t trip at Sedam end

DR Trigger time: NA

DR not submitted.

From EL, Zone-3 operation was

observed.

220kV Sedam RTPS line-2

56

Sedam End RTPS End

DR Trigger time: NA

Line didn’t trip at Sedam end due to

mechanical problem in breaker.

DR Trigger time: 01:59:47.095 hrs

BN fault (Ifault-B=3.646kA)

Zone-1

Carrier sent

220kV Sedam Tandur line-1

Sedam End Tandur End

DR Trigger time: NA

Line didn’t trip at Sedam end


EF pickup.

From EL, DEF operated in 2820ms

Annexure-III

Page 56 of 81

PMU PlotsPoints for Review

(1). Status of A/r of 220kV Sedam RTPS line-2 at both the ends(2). Non opening of breaker at Sedam end for 220kV Sedam RTPS line-2.(3). Absence of LBB protection at 220kV Sedam end.(4). DR of 220kV Sedam RTPS line-1 at RTPS end not submitted.(5). DR of 220kV Sedam RTPS line-2 at Sedam end not submitted.

57


• The Circuit Breaker of RTPS-1 &2 lines which was due for replacement has been replaced on 24th and 25th July 2019.7.2019

• The control cables required for Bus Bar Protection work has been arranged, the work is expected to be completed shortly.

Annexure-III

Page 57 of 81

58


Annexure-III

Page 58 of 81

85.II.27. Tripping of 400kV Vemagiri-GMR line-1&2 on 14-06-2019 at 09:33 hrs

• Triggering incident: Y-Phase LA failure at Vemagiri end of 400kV

Vemagiri-GMR line-1 .

• Line-2 tripped at GMR end only on SOTF

DR

59


400kV Vemagiri-GMR line-1

Vemagiri End GMR End

DR Trigger time: NA

DR not submitted.

From EL, Zone-1, carrier send and A/r

operated were observed.

DR Trigger time: 09:33:17.028hrs

Y phase fault

Carrier received

A/r operation couldn’t be validated

DR

Annexure-III

Page 59 of 81

GI\2.27\GMR Vemgr-1\17359_SENDEL-GMR 1 EVENT.pdf

GI\2.27\GMR VEMAGIR LINE-1&2 14-JUN-2019 EL & DR.pdf

60

400kV Vemagiri-GMR line-2

Vemagiri End GMR End

DR Trigger time: NA

Line didn’t trip at Vemagiri

end

DR Trigger time: 09:33:17.036hrs

SoTF/ToR trip

Points for Review

(1). Tripping of 400kV Vemagiri GMR line-2 at GMR end on SOTF operation

DR

Annexure-III

Page 60 of 81

GI\2.27\GMR VEMAGIR LINE-1&2 14-JUN-2019 EL & DR.pdf

85.II.28. Tripping of 400/220kV ICT-2 at Hoody substation on 16-06-2019 at 19:20 hrs

• ICT-2 got tripped on operation

of HV over-flux protection

• V/f =1.211, 0.508sec

ELDR

61


1). Loose wire found in voltage circuit rectified.

2).The Over Flux settings have been revised as follows:

v/f setting for alarm: 1.1 time V nominal, Time delay 20 seconds;

v/f trip setting : v/f is 1.2 time V nominal;Time delay 10 seconds;

SCADA Plot

Annexure-III

Page 61 of 81

GI\2.28\17363_SENDEL-ICT2 EL.pdf

GI\2.28\17363_SENDDR-ICT-2 OVERFLUX 24HV - 16.06.19.pdf

85.II.29. Multiple tripping at 220kV Nunna substation on 16-06-2019 at 06:16 hrs

• Triggering incident: failure HV side B phase CT of 220/132kV transformer-1

(connected to 220kV Bus-2) in 220kV Nunna station.

• Bus-1 and Bus-2 BBP operated.62

Annexure-III

Page 62 of 81

63

PMU Plots

DR Analysis

DR Trigger time: 04:19:59.735 hrsBN faultTrip 87BB Zone 2

EL Analysis

ELDR

Annexure-III

Page 63 of 81

Raichur Solapur\17058_SENDEL-765kV_Raichur-Solapur_line1_EL_27042019.pdf

GI\2.29\NUNNA SS\17368_SENDDR-041959.pdf

85.II.30. Tripping of 400kV Hiryur-Nelamangala-1 and 400kV Gooty-Nelamangala on 22-06-2019 at 04:06hrs

• Triggering incident: 'Y' phase bushing of Hiriyur line-1 reactor failed at

Nelamangala: R-Y phase fault.

• 400kV Gooty-Nelamangala line : Line tripped at Nelamangala end only

due to mal-operation of Main-2 distance protection relay

• No delayed fault clearance

64

Remedial Actions Furnished by KPTCL

Action has been taken to replace the same by commissioning new CRP mounted in bay KIOSK under R&M works.

Annexure-III

Page 64 of 81

65

PMU Plots


Hiryur End Nelamangala End


RY fault

M1 operated

A/r lockout


Distance relay pickup

Main 2 trip DR

400kV Hiryur-Nelamangala-1

DR

Gooty End Nelamangala End

DR Trigger time: NA

Line didn’t trip at Gooty end


Distance relay pickup

Main 2 trip

400kV Gooty-Nelamangala

DR

Annexure-III

Page 65 of 81

GI\2.30\Hiriyur - Nelmngl\17375_RENDDR-DR -2 Up.pdf

GI\2.30\Hiriyur - Nelmngl\17375_SENDDR-HYR_NLM_LINE1_DR.pdf

GI\2.30\Gooty - Nelmngla\17376_RENDDR-DR.pdf

85.II.31. Tripping of 400/220kV ICT-1&2 at Munirabadsubstation on 24-06-2019 at 20:50 hrs

• Triggering incident: failure of Y phase CT in 220kV Munirabad-Kalyani steel

feeder at Kalyani steel end

• Line got tripped on operation Zone-1. However zone-1 operation was

observed after 280ms after occurrence of fault.

• ICTs tripped due to operation of High set of backup earth fault relay (ICT-1 :

6.63kA, ICT-2 : 5.1KA)

66

At Munirabad end, ICT DOC high set settings are 400kV side: 4kA & 220kV side 5.0kA

Annexure-III

Page 66 of 81

Munirabad End Kalyani Steel End


YN fault, subsequently YBN fault

Zone 2 pickup

Zone-1operated, Carrier sent

Fault current persistent for ~250ms.

DR Trigger time: NA

67

PMU Plots

DR

Observations from DR:220kV Munirabad- Kalyani Steel

400/220kV ICT-1

Munirabad

400/220kV ICT-2

Munirabad

DR Trigger time:

20:50:55.209 hrs

3 PH GR-A OPTD

Ifault=6.63kA

persistent for

~200ms.

DR Trigger time:

20:50:55.209 hrs

IV B/U PROT OPTD

Ifault=5.2863 kA

persistent for ~125ms.


220kV Kalyani Steel line distance relay settings have been reviewed and

revised consequent to the tripping.


DR DR

Annexure-III

Page 67 of 81

GI\2.31\MNBD - KLYN STEEL\17406_SENDDR-220kV_Munirabad_Kalyani_line-DR-24062019.pdf

GI\2.31\ICT-1\17382_SENDDR-Munirabad_ICT_1_DR_24062019.pdf

GI\2.31\ICT-2\17383_SENDDR-Munirabad_ICT_2_DR_24062019.pdf

85.II.32. Tripping of HVDC Talcher-Kolar Pole-1&2

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

1Tripping of HVDC Talcher-

Kolar Pole-131-05-2019 at 18:30 hrs

Pole 1 tripped on Line fault. Pole-1 restarted three times and

went into RVO mode. The fourth fault caused tripping of the

pole. Pole-2 went to ground return mode.

SPS Trip Signal-1 and

Trip Signal-2 operated

at Kolar end since total

power loss was ~1700

MW


Kolar Pole-1&205-06-2019 at 19:01 hrs

HVDC Talcher-Kolar Pole-1 tripped on receipt of ESOF

(Emergency Switch On to Fault) signal at Kolar from Talcher

end. Pole-2 went to metallic return mode with a power flow

of 900MW at Kolar end. Subsequently at 19:02 Hrs, HVDC

Talcher-Kolar Pole -2 also tripped due to operation of under

voltage protection at Kolar end

After tripping of Pole-1

SPS Trip Signal-1

operated leading to

total load relief of

700MW.



Pole 1 tripped on receipt of ‘ESOF” from other side at 12:10

Hrs. Pole-2 shifted to metallic return mode of operation

SPS Trip Signal-1

operated at Kolar end

leading to total load

relief of 700MW.



While carrying out the switching operation of charger-2 to

Charger-3 for enabling maintenance by OEM, Pole -2 got

tripped due to suspected over voltage in 24V system. After

tripping of Pole-2, Pole-1 continued to operate in metallic

return mode

SPS at Kolar did not

operate since total

power loss after

tripping of Pole-2 was

less than 500 MW

68

Annexure-III

Page 68 of 81

85.II.33. Frequent Tripping of 220kV Lower Sileru-KTPS

Sl.

No. Details of Event Date & Time ReasonFault

LocationDR

1220kV Lower

Sileru-KTPS line

01-06-2019 at

00:00 hrs

R-phase to ground fault. Auto-reclose

was successful at Lower sileru end. A/r

is not enabled at KTPS

95.6KM from

Lower Sileru

end.

2220kV Lower

Sileru-KTPS line

02-06-2019 at

15:30 hrs

R-phase to earth fault occurred in line.

Auto-reclose was successful at Lower

sileru end. A/r is not enabled at KTPS.

51KM from

Lower

Sileru end.

3220kV Lower

Sileru-KTPS line

09-06-2019 at

11:58 hrs

B-phase to earth fault occurred in line.

Zone-2 operated at KTPS and Earth fault

at Lower sileru. Suspected high

resistance fault.

119 KM

from

Lower

Sileru end.

4220kV Lower

Sileru-KTPS line

12-06-2019 at

14:23 hrs

Y-phase to earth fault occurred in line.

Auto-reclose was successful at Lower

Sileru end. A/r is not enabled at KTPS

76KM from

Lower

Sileru end.

69

DR

DR

DR

DR

Line Length= 114 KM

DR

DR

DR

DR

Annexure-III

Page 69 of 81

GI\2.33\09-06\17330_SENDDR-Oscillography 090619.pdf

GI\2.33\12-06-19\17352_SENDDR-Oscillography 120619.pdf



GI\2.33\01-06\17266_RENDDR-June 1st.pdf

GI\2.33\02-06\17267_RENDDR-June 2nd-converted.pdf

GI\2.33\09-06\17330_RENDDR-M1 09-06-2019.pdf

GI\2.33\12-06-19\17352_RENDDR-M1&M2.pdf

70


Annexure-III

Page 70 of 81

Failure or Non-Operation of Auto Reclose During Transient Fault

71

Annexure-III

Page 71 of 81

Sno. Name of the Element

Date and Time

Reason DR EL

1

Tripping of

400kV Ghani-

Narnoor line-1

21-05-2019 at

15:11 hrs

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

not successful as fault was persistent in nature. Fault was

cleared in zone-2 time during A/r attempt

2

Tripping of

400 kV Kudgi

PG - Tumkur

line - 2

21-05-2019 at

15:30 hrs

Y-phase to earth fault occurred in line. Auto-reclose was

successful at Tumkur. At Kudgi end Auto-reclose was not

attempted

3

Tripping of

400kV

Talarichevu -

Jamalamadugu

ckt-1

21-05-2019

17:51 hrs

B -ph to ground fault in the line.. Auto reclose operated at

Talarichevu end but tripped on persistent fault. Auto

reclose not attempted at Jamalamadugu end

4

Tripping of

400kV

Talarichevu -

Jamalamadugu

ckt-1

22-05-2019 at

19:21 hrs

R phase to Earth fault in the line. At Jammalamadugu end

A/r operated and line tripped due to persistent fault. Main

CB A/r not attempted at Talarichevu


72

Annexure-III

Page 72 of 81

AR\3.1\17173_SENDDR-21.05.19 15.13.28 M1.pdf

AR\3.1\17173_RENDDR-21.05.19.15.13 GHANI1M1.pdf

AR\1\16785_SENDEL-EVENT LOGGER.pdf

AR\1\16785_RENDEL-2KYPU M1 Event @ PUN.pdf

AR\3.2\17175_SENDDR-DR.pdf

AR\3.2\17175_RENDDR-DR.pdf

AR\2\16806_SENDEL-EL.pdf

AR\2\16806_RENDEL-220KV KAYAMKULAM PUNNAPURA 2.pdf

AR\3.3\17177_SENDDR-DR M1 MICOM 11.pdf

AR\3.3\17177_RENDDR-407 TCV1 21.05.19 DR.pdf

AR\3\16808_SENDEL-KMM-KLPK-2_060319_1419Hrs_EL.pdf

AR\3\16808_RENDEL-EL KMM DT.06.03.2019.pdf

AR\3.4\17182_SENDDR-B401M2DR.pdf

AR\3.4\17182_RENDDR-407 TCV1 22.05.19 M2 DR.pdf

AR\3.4\17182_RENDDR-407 TCV1 22.05.19 M2 DR.pdf

AR\4\16811_RENDEL-SLM_NLY_LINE2_EL.pdf


Date and Time

Reason DR EL

5

Tripping of

400 kV Kudgi

PG – Tumkur

line-2

23-05-2019

at 22:05 hrs

Y-phase to earth fault occurred in

line. Auto-reclose was successful

at Tumkur end. At Kudgi(PG) end

A/r was not attempted due to A/r

block

6

400 KV

Thiruvelam –

Palavadi line-

1

28-05-2019

at 18:04 hrs

B-phase to earth fault. A/r attempt

could not be validated.

7

Tripping of

400kV

Pugalur-

Karaikudi

line-1

31-05-2019

at 17:44 hrs

R-phase to earth fault occurred in


at Karaikudi, At Pugalur end there

was 3-phase trip

8

Tripping of

400kV

Ramagundam

-Ghanapur

line

02-06-2019

at 13:23 hrs

R-phase to earth fault occurred in


at Ghanapur and A/r was not

attempted at Ramagundam due to

DT receive


73

Annexure-III

Page 73 of 81

AR\3.5\17185_SENDDR-KDG_TMK_LINE2_DR.pdf

AR\3.5\17185_RENDDR-TMK_KDG_LINE2_DR.pdf

AR\5\16846_SENDEL-JULURUPADU_BTPS_LINE_2_EL 14-03-19.PDF

AR\5\16846_RENDEL-Events.pdf

AR\3.6\17223_SENDDR-400kV_ TVLM_PALAVADI FEEDER.1_ DR.pdf

AR\3.6\17223_RENDDR-400kV_PALAVADI_TVLM FEEDER.1_ DR.pdf

AR\6\16849_SENDEL-SURYAPET 2 14032019 21M1.pdf

AR\6\16849_RENDEL-SURYAPET_VTPS_LINE_2_EL 14-03-19.pdf

AR\3.7\17263_SENDDR-PGLR_KRKD_LINE1_DR.pdf

AR\3.7\17263_RENDDR-KRKD_PGLR_LINE1_DR.pdf

AR\8\16881_SENDEL-24032019 Nellore.pdf

AR\8\16881_RENDEL-20190324 VTPS EL at 400 kV Nellore APTRANSCO Export_20190325_1240.pdf

AR\3.8\17270_SENDDR-NTPC RAMAGUNDAM HYDERABAD LINE 3 02062019 DR.pdf

AR\3.8\17270_RENDDR-HYD-RDM-3_020619_1326Hrs_DR.pdf

AR\7\16852_SENDEL-400kV_Khammam_Kalpaka_Line_EL_15032019.pdf

AR\7\16852_RENDEL-el kmm 15.03.2019.pdf


Date and Time

Reason DR EL

9

Tripping of

400kV Kalikiri-

RYTPP line-2

02-06-2019

at 19:15 hrs


Auto-reclose was successful at Kalikiri

and A/r not attempted at RYTPP due to

A/r lockout

10

Tripping of

400kV VTPS-

SURYAPET

line-1

02-06-2019

at 13:15 hrs


Auto-reclose was successful at

Suryapet end. 2nd fault during reclaim

time resulted in three phase trip. At

VTPS end A/r was not attempted

11

Tripping of

765 KV

Kurnool - NPS

line-1

02-06-2019

at 17:41 hrs

R-phase to earth fault occurred in line.

A/r not attempted due to PLCC

channel fail.

12

Tripping of

400KV-

Maheshwara

m PG-

Mahbubnagar

line-1

06-06-2019

at 19:18 hrs

Y phase to Earth fault in the line. A/r

not operated at Mahbubnagar

Item no 2.18


74

Annexure-III

Page 74 of 81

AR\3.9\17268_SENDDR-RTPP-II DR 02.06.2019.pdf

AR\3.9\17268_RENDDR-21M2_406_02.06.19_DR1.pdf

AR\9\NEYVELI TS2_VILLIANUR_LINE_EL.pdf

AR\9\16890_RENDEL-2019 03 29 Event Logger Villianur - Neyveli.pdf

AR\3.10\17274_SENDDR-Suryapet 1 02062019 DR.pdf

AR\3.10\17274_RENDDR-SURYAPET_VTPS_LINE_1_DR 02-06-19.pdf

AR\10\16912_SENDEL-RTPS_RAICHUR PG2_LINE_EL.pdf

AR\10\16912_RENDEL-EL.pdf

AR\11\16923_SENDDR-SURYAPET_KETHIREDDYPALLY_LINE_1_DR 07-04-19.pdf

AR\3.12\17318_SENDDR-400kV_Maheshwaram_Velatoor_line1-DR-06062019.pdf

AR\3.12\17318_RENDDR-VELTOOR_MAHESHWARAM(PG)_LINE_1_DR 06-06-19.pdf




Date and Time

Reason DR EL

13

Tripping of

400 kV JSW -

Guttur line

08-06-2019

at 13:13 hrs

B-phase to earth fault occurred in

line. A/r was not successful as fault

was persistent. A/r not attempted at

Guttur.

14

Tripping of

400kV Kaiga-

Guttur line-2

18-06-2019

at 15:03 hrs

R-phase to earth fault. Auto-reclose

attempt at Guttur end was not

successful as fault was persistent in

nature. Attempt for A/r could not be

established from Kaiga end EL


75

Annexure-III

Page 75 of 81

AR\3.13\17326_SENDDR-JSW_GUTTUR_LINE2_DR.pdf

AR\3.13\17326_RENDDR-Merged JSWEL 08.06.19 at 12.55hrs.pdf

AR\9\NEYVELI TS2_VILLIANUR_LINE_EL.pdf

AR\9\16890_RENDEL-2019 03 29 Event Logger Villianur - Neyveli.pdf

AR\3.14\17370_SENDDR-KAIGA_GUTTUR_LINE2_EL.pdf

AR\3.14\17370_RENDDR-Kaiga-2 18.06.19 at 2.52hrs.pdf



Tripping at One End/ PLCC Mal-operation

76

Annexure-III

Page 76 of 81


Date and Time

Reason DR EL

1

Tripping of 400kV

Julurupadu-

Managuru line -2

20-05-2019

at 15:57 hrs

Line tripped at Julurupadu end only on

direct trip receive

2

Tripping of 400kV

Khammam

Mamidapally line-

1

27-05-2019

at 18:16 hrs

Line tripped only at Mamidapally end

due to suspected PLCC maloperation

3

Tripping of 765 kV

Raichur- Kurnool

line- 2

02-06-2019

at 17:41 hrs

Line tripped on operation of Over

voltage stage-1 at Kurnool end. Direct

trip was not sent to Raichur due to

failure of PLCC channel at Kurnool and

line was holding from Raichur.

4Tripping of 765 KV

KURNOOL - NPS 2

02-06-2019

at 17:41 hrs

Line tripped on operation of over

voltage stage-1 protection at Kurnool.

Direct trip was not sent to NPS due to

PLCC channel fail


77

NA

Annexure-III

Page 77 of 81

PLCC\4.1\17165_SENDEL-JULURUPADU_BTPS_LINE_2_EL 20-05-19.PDF

PLCC\4.1\17165_SENDDR-JULURUPADU_BTPS_LINE_2_DR 20-05-19.pdf

PLCC\4.1\17165_RENDEL-EL20.05.2019-404BAY.pdf

PLCC\4.4\17275_SENDDR-KLN-NPS-1_020619_1741Hrs_DR.pdf

PLCC\4.4\17275_RENDDR-KLN-NPS-1_020619_1741Hrs_DR.pdf

PLCC\4.2\17217_SENDEL-On 27.pdf

PLCC\4.2\17217_RENDEL-EL-2-KHMM-1-270519.pdf

PLCC\4.3\17281_SENDEL-765kV_Raichur_Kurnool_02062019.pdf

PLCC\4.3\17281_RENDEL-765kV_Kurnool_Raichur_Line2_EL_02062019.pdf

PLCC\4.4\17275_SENDEL-KLN-NPS-1_020619_1741Hrs_EL.pdf

PLCC\4.4\17275_RENDEL-KLN-NPS-1_020619_1741Hrs_EL.pdf

PLCC\4.2\17217_SENDDR-On 27.pdf

PLCC\4.2\17217_RENDDR-DR-KHMM-1-270519.pdf

PLCC\4.3\17281_SENDDR-765kV_Raichur_Kurnool_02062019.pdf

PLCC\4.3\17281_RENDDR-765kV_Kurnool_Raichur_Line2_DR_02062019.pdf


Date and Time

Reason DR EL

5

Tripping of 400kV

Warangal-

Bhoopalapalli line-1

& Boopalppalli

Chandlapur line-1

08-06-2019

at 1:35 hrs

400kV Warangal-Bhoopalapalli line-

1 line tripped only at Boopalappalli

end on OV st-1 protection operation

and DT was not sent to Warangal end

due to failure of both PLCC channels.

400kV Boopalppalli Chandlapur line-1

tripped at Boopalpalli end due to DT

Receive

6

Tripping of 400kV

Kayathar-Kanarpatty

line-1 & 2

10-06-2019

at 12:22 hrs

Line-1 & 2 tripped at Kanarpatty end

due to spurious DT sent from

kayathar end. Feeder did not trip at

Kayathar end

7

Tripping of 400kV

Ramadugu-

Singareni line

11-06-2019

at 08:24 hrs

Line tripped due to Direct Trip receive

at Ramadugu end


78

NANA

NA NA

NANA

Annexure-III

Page 78 of 81

PLCC\4.6\54\17333_SENDEL-400KV KAYATHAR_KANARPATTY_ FEEDER.1_EL.pdf

PLCC\4.6\54\17333_RENDEL-400kV_KANARPATTY_KAYATHAR_ FEEDER.1_ EL.pdf

PLCC\5\16939_RENDDR-MBD-RTPS_100419_1552Hrs_DR.pdf

PLCC\5\16939_RENDEL-MBD-RTPS_100419_1552Hrs_EL.pdf

PLCC\4.6\55\17336_SENDEL-400KV KAYATHAR_KANARPATTY_ FEEDER_2_EL.pdf

PLCC\4.6\55\17336_RENDEL-400kV_KANARPATTY_KAYATHAR_ FEEDER.2_ EL.pdf

PLCC\4.5\62\17405_SENDDR-DR.pdf

PLCC\4.5\62\17405_RENDDR-CHANDULAPUR_BHOOPALPALLY_LINE_2_DR 08-06-19.pdf

PLCC\6\16969_SENDEL-NNR-SRISALAM 11-04-19 EVENTS.pdf

PLCC\6\16969_RENDEL-srisailam_KURNOOL_LINE_EL.pdf

PLCC\4.7\49\17348_SENDDR-RAMADUGU_SINGARENI_LINE_1_DR 11-06-19.pdf

PLCC\4.7\49\17348_SENDEL-RAMADUGU_SINGARENI_LINE_1_EL 11-06-19.pdf

PLCC\4.5\61\17323_SENDDR-400kV_Warangal_Bhoopalapalli_Line1&2-08062019.pdf

PLCC\4.5\61\17323_RENDDR-DR.pdf

79

Additional Slides

Annexure-III

Page 79 of 81

80

Annexure-III

Page 80 of 81

81

Tripping of 400kV Hoody-Yelahankaline-1 on 25-05-2019 at 20:41 hrs

Annexure-III

Page 81 of 81

Meeting

No /

Index

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

Implementation

Status of Implementation of PCSC Recommendations Remarks Latest Status

(To be filled up by the Constituent)

PGCIL (SR-I) mail received on 27-04-2016:

1. The firmware of REL670 is being upgraded. ------- Completed.

2. The recording of events in msec interval is being taken up with OEM. Henceforth,

for analysis purpose, we will provide larm list which has msec time stamp. --------

Completed.

3. End to end testing of PLCC code transmision and tuning of channels carried out. ----

--- Completed.

4. Procurement of differential protection for 400kV NPS-NLR D/C and 400kV RCR-

RTPS-D/C is under tendering. The legends modified in Event/alarm list. Provision of

diff. relay for all short lines emanating from NPS is being taken up with our

corporate.

----- Pending.

PGCIL(SR-I) RVMD 14-07-2016:

4. The proposal for procurement of Line differential Protections for 400kV Raichur -

RTPS-1 & 2 and 400kV Nellore - NPS - 1 & 2 lines has been approved and tender is

30-12-2015 at

06:02hrs

50/I/2 1.PGCIL (SR-I) to furnish Action Taken Report on the

findings of OEM on relay mal-operation at NPS end

on 400 kV NPS – NCC line to PCSC forum.

2. PGCIL (SR-I) to appropriately configure Station

Event Logger at NPS to record events at msec interval.

3. PGCIL (SR-I) to carry out PLCC end-to-end testing

in coordination with TPCIL for 400 kV NPS –TPCIL

line.

4.PGCIL (SR-I), MEPL, SEL, TPCIL & NCC to take

steps to provide line differential protection at their

respective ends on all 400 kV lines (except Gooty line)

emanating from Nellore Pooling Station, and furnish

an action plan to implement the same.

Status of Pending Implementation of PCSC Recommendations as on 19.08.2019 (up to 85th Meeting)

KPTCL Mail dated 27-05-2015:

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

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

--- Pending

3. --- Pending

KPTCL Mail dated 29-07-2015:

1. Initial Tendering stage. --- Pending

2. --- Pending

3. --- Pending

KPTCL Mail dated on 23-01-2016:

1. Detailed estimate prepared for taking up the work. CEE, Transmission Zone,

Gulbarga will take up necessary procurement and further execution. --- Pending

2. --- Pending with PGCIL (SR-I).

3. --- Pending

PGCIL (SR-I) Mail dated 14.07.2016:

2. Relay settings of all the stations in SRTS-1 were derived as per Ramakrishna

Commettee recomendations and implemented" --- Completed.

KPTCL Mail dated 16.12.2017:

1) & 3). DPR is approved. Tender is to be called by CEE,TZ Kalaburgi --- Pending

Review Meeting dated 19.12.2017:

1. KPTCL informed that Tenders for providing BBP would be called in Jan-Feb,

2018; Supply of the same is targeted by September, 2018; Erection & Commissioning

is targeted by January, 2019

--- Pending

3. PGCIL (SR-I) informed that time-synchronization of 220 kV side is in place. ---

Completed.

KPTCL mail dated 19.12.2018:

1. DPR preapared for the work of providing Bus Bar Protection to 220kV buses at

Guddadahally is approved. Tender is to be invited by CEE,TZ .


1. Tender would be floated in January 2019. Works would be completed in 6 months

16-07-201434/I/6 400/220 kV ICT-1 & 2 at

Munirabad

As reported directional over current relay of ICT’s

operated due to snapping of line jumper in 220kV

Lingapur line.

1. Bus bar protection shall be provided by asset

owner ( i.e KPTCL).

2. Settings for main distance protection &

Overcurrent protection shall be examined and

reviewed.

3. Time synchronization of the Substation shall be

ensured.

KPTCL/

PGCIL (SR-I)

Pending

(with KPTCL)

Multi-Utilities

Complete outage of TPCIL

power station

PendingPGCIL (SR-I),

MEPL, SEL, TPCIL,

NCC

Running units at Thermal Powertech power Station

tripped due to tripping of 400kV Nellore pooling

station (NPS)-TPCIL line and 400kV Nellore pooling

station (NPS)-NCC line

Annexure-IV

Page 1 of 48


4. LDP relays procurement is under process. Procurement will be completed by Feb-

2018. TPCIL has to give written confirmation for LDP relay procurement. For want

of written confirmation from TPCIL, PGCIL approving authority has withheld the

LDP proposal.


4. PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL

to complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit

written confirmation to PGCIL (SR-I) by 29.12.2017. PGCIL (SR-I) assured that

with receipt of above confirmation from TPCIL by Dec, 2017, they would be able to

complete the work by FEbruary, 2018.

APTRANSCO informed that they would be able to implement LDP from their &

APGENCO side by April, 2018.

In this regard, PCSC forum made it clear that the recommendation is about providing

LDP as both Main-I & Main-II relays on all stated lines in Nellore Complex, ans

PGCIL (SR-I) mail dated 20.06.2018:

PGCI(SR1) procuring LDP relays for retrofitting of Main-1&2 distance relays.

Tenders are invited from bidders & tender floated. Technical bid opening in this

week.


PO placed on M/s GE & TD India Ltd on 24.09.2018. Supply of relays will be

completed by Jan'2019 and commissioning by Mar'19.


4. PGCIL-SR1: LDP relays (Main-1) commissioned in 400kV NPS-TPCIL-1 Line

during opportunity shutdown. NPS-NCC D/C & NPS-TPCIl D/C lines LDP relay

retrofitting planned in June & July -2019.

In 154th OCC meeting SRLDC/SRPC has advised to re-schedule LDP

commissioning tentatively to Sep/Oct’2019.57/II/9 Tripping of 400 kV Nellore

(PG) - NPS line-1, 400 kV

Krishnapatnam-Nellore (AP)

lines -1&2 and 400kV NPS -

MEPL line

18-07-2016

at 19:05 hrs

APTRANSCO mail dated on 20-12-2016:

Issue was addressed to the concerned for necessary action.

APTRANSCO mail dated on 24-05-2017:

Meeting was conducted and the relays procurement for all the loctions is under

progress.

APTRANSCO mail dated on 20-10-2017 & 22.11.2017:

Relays procurement for all the locations is under progress.

APTRANSCO Mail dated 15.12.2017:

Technical bids opened. PQ evaluation under progress . Price bids expected to open in

next week.


LDP relays procurement is under process. Procurement will be completed by Feb-

2018. TPCIL has to give written confirmation for LDP relay procurement. For want

of written confirmation from TPCIL, PGCIL approving authority has withheld the

LDP proposal.


PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL to

complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit



complete the work by FEbruary, 2018.





asked all stakeholders to ensure & comply with the same.

Triggering incident was snapping of Y phase conductor

in 400kV Nellore (PG) - NPS line-1. Distance relay at

Krishnapatnam end over-reached in Zone-1, and

resulted in tripping of 400kV Krishnapatnam – Nellore

(AP) lines - 1&2 from Krishnapatnam end. Distance

relay at MEPL over-reached and resulted in tripping of

MEPL-NPS line from MEPL end.

PGCIL (SR-I), TPCIL, MEPL, SEL, SGPL,

APTRANSCO, APGENCO and SDSTPS to

implement line differential protection on all 400 kV

transmission lines (of length less than 50 km)

emanating from Nellore PS, Nellore (PG) SS, and

Nellore (AP) SS. [It may be noted here that the cut-off

length of 50 km has been specified with a view to

exclude only long transmission lines].

APGENCO/

PGCIL(SR-I)/

TPCIL/MEPL/SEL/

SGPL/ APTRANSCO

Pending

30-12-2015 at

06:02hrs

50/I/2 1.PGCIL (SR-I) to furnish Action Taken Report on the

findings of OEM on relay mal-operation at NPS end

on 400 kV NPS – NCC line to PCSC forum.

2. PGCIL (SR-I) to appropriately configure Station

Event Logger at NPS to record events at msec interval.

3. PGCIL (SR-I) to carry out PLCC end-to-end testing

in coordination with TPCIL for 400 kV NPS –TPCIL

line.

4.PGCIL (SR-I), MEPL, SEL, TPCIL & NCC to take

steps to provide line differential protection at their

respective ends on all 400 kV lines (except Gooty line)

emanating from Nellore Pooling Station, and furnish

an action plan to implement the same.

Complete outage of TPCIL

power station

PendingPGCIL (SR-I),

MEPL, SEL, TPCIL,

NCC

Running units at Thermal Powertech power Station

tripped due to tripping of 400kV Nellore pooling

station (NPS)-TPCIL line and 400kV Nellore pooling

station (NPS)-NCC line

Annexure-IV

Page 2 of 48

APTRANSCO Mail Dated 24.04.2018:

ABB make LDP relays inspection is completed. SNEIDER make LDP relays

inspection yet to be completed. Delivery of relays expected in the 1st weak of May-

2018.


SNEIDER make LDP relays inspection yet to be completed.Delivery of relays

expected in the month of june 2018.


PGCI(SR1) procuring LDP relays for retrofitting of Main-1&2 distance relays.


week.


ABB make LDP relays are delivered. Schneider make LDP relays inspection to be

offered by the company.

APTRANSCO Mail Dated 25.07.2018:APTRANSCO Mail Dated 25.09.2018:

ABB make LDP relays for Main-1 protection were delivered earlier and schneider

make LDP relays for Main-2 protection are delivered in this week.


ABB & SCHNEIDER Relays are drawn and available at site. To be commissioned

in coordination with the Alstom (Area) engineers who implemented SAS.


PGCIL(SR-1): PO placed on M/s GE & TD India Ltd on 24.09.2018. Supply of

relays will be completed by Jan'2019 and commissioning by Mar'19

APTRANSCO MAIL DATED 22.01.2019:

The relays are yet to be commissioned.

APTRANSCO mail dated 15.03.2019:

Commissioning of LDP relays scheduled in the month of April 2019.


Schnider make P546 LDP relays commissioned in place of Main-1 relays at Nellore

end for 400KV Krishnapatnam feeder on 26/03/19 and for feeder-2 on 27/03/19.

ABB make RED670 relays yet to be commissined in place of Main-2 relays.


PGCIL-SR1: LDP relays (Main-1) commissioned in 400kV NPS-TPCIL-1 Line

during opportunity shutdown. NPS-NCC D/C & NPS-TPCIl D/C lines LDP relay

retrofitting planned in June & July -2019.

In 154th OCC meeting SRLDC/SRPC has advised to re-schedule LDP

commissioning tentatively to Sep/Oct’2019.


ABB make RED670 relays testing is under process and will be commissioned in

place of Main-2 relays for Krishnapatnam-1&2 feeders by 30.06.2019 at 400KV

Manubolu SS.


ABB make RED670 type LDP relays commissioned in place of Main-2 relays at

Nellore end for 400KV Krishnapatnam feeder-1 on 17/07/19 and for feeder-2 on

15/07/19. The 400KV Krishanapatnam line-2 main-2 relay is in service in

Differential mode. But due to non availability of suitable patch cards, Main-1 of KP-

1 & Main-1&2 of KP-2 feeders are not in differential mode but in Distance mode.

The diffential mode of operation will be kept in service by after purchasing suitable

patch cards.

57/II/9 Tripping of 400 kV Nellore




MEPL line

18-07-2016

at 19:05 hrs






relay at MEPL over-reached and resulted in tripping of

MEPL-NPS line from MEPL end.

PGCIL (SR-I), TPCIL, MEPL, SEL, SGPL,

APTRANSCO, APGENCO and SDSTPS to

implement line differential protection on all 400 kV

transmission lines (of length less than 50 km)

emanating from Nellore PS, Nellore (PG) SS, and

Nellore (AP) SS. [It may be noted here that the cut-off

length of 50 km has been specified with a view to

exclude only long transmission lines].

APGENCO/

PGCIL(SR-I)/

TPCIL/MEPL/SEL/

SGPL/ APTRANSCO

Pending

Annexure-IV

Page 3 of 48

NTPC mail dated 07.12.2017:

1. High set DEFR on 220 KV lines is disabled ----Completed

2. ---- Pending


TSTRANSCO informed that the works are under progress, and are targeted to be

completed in 3 months time.

TSTRANSCO MAIL DATED 20.01.2018:

Line Differential Protection will be provided within 3 months i.e., by end of March,

2018.


Line Differential Protection relays are under procurement and will be provided by end

of May, 2018.


Line Differential relays will be supplied to site by manufacturer by end of May, 2018

and erection will be completed by end of June, 2018.


Inspection of the relays is completed and the relays are received at stores. Relays are

to be drawn and commissioned. Work is expected to be completed by end of


Relays will be commissioned by end of February, 2019.


Replacement of porcelain insulators with Polymer insulator for 4 Km radius ( in

Chennai area) from NCTPS.2 in 400kV SVCM & Alamathy feeders were completed.

TSTRANSCO mail dated 22.06.2019:

2. Relay erection work is under progress and will be completed by end of July, 2019.

11-06-2017

at 19:46hrs

Triggering incident was failure of 220 kV

B-phase LA in ICT-3 LV extension feeder (220KV

line-2) at Malayalapalli substation

1. NTPC to disable high-set of DEFR on the 220 kV

lines emanating from their Ramagundam STPS.

2. NTPC/ TSTRANSCO to provide Line Differential

Protection (with or without pilot) on 220 kV

Ramagundam – Malayalapalli lines – 1 & 2 & 3.

66/ II/ 10 Tripping of 400/ 220 kV

ICT’s – 3 & 4 at

Ramagundam STPS

NTPC-Ramagundam/

TSTRANSCO

Pending

Annexure-IV

Page 4 of 48

69/I/2 Complete outage of 400kV

TPCIL station

30-10-2017 at

21:37 hrs

400kV TPCIL - Nellore line-1 got tripped at TPCIL

end during failure of LA of Station Transformer-2 at

TPCIL. Running Units at TPCIL got tripped due to loss

of evacuating line. 400kV TPCIL - Nellore PS line-2

was under emergency shutdown

1. TPCIL to configure DEF protection such that it

remains in blocked condition as long as Distance

Protection is active, and becomes active only when

distance protection does not pickup.

2.PGCIL (SR-I) to ensure healthiness of Carrier

communication, and the set PUP mode of carrier aided

scheme operates reliably on TPCIL lines 1 & 2.

TPCIL/

PGCIL (SR-I)


PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL to

complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit



complete the work by February, 2018.





asked all stakeholders to ensure & comply with the same.


2. PGCI(SR1) procuring LDP relays for retrofitting of Main-1&2 distance relays.


week.


2. PO placed on M/s GE & TD India Ltd on 24.09.2018. Supply of relays will be

completed by Jan'2019 and commissioning by Mar'19.

Review Meeting on 20.12.2018 & 27.06.2019:

Pending

APTRANSCO maild ated 30.01.2018:

1. Pending...

2.A/R scheme on 400kV Kurnool (PGCIL) feeder-2 will be checked after getting LC.

APTRANSCO maild ated 24.04.2018 & 24.05.2018 & 26.06.2018:

1. Pending...

2. B Ph auxilary trip relay is found defective. The same is to be replaced by M/S

PGCIL. Ii) PD relay event is configured in the EL as per the recommendation.


1. ---Pending

2. PGCIl(SR-1): B-Ph auxiliary relay problem rectified at Narnoor end by replacing

relay contact. ---Completed


1) Bays and lines pertains to PGCIL .

2) ---Completed.


1) PO placed on M/s GE & TD India Ltd on 24.09.2018. Supply of relays will be

completed by Jan'2019.


Pending [with PGCIL (SR-I)]


PGCIL(SR-1):

This issue of retrofitiing of distance relays with LDP relays in Kurnool(PG) –

Kurnool(AP) D/C lines has been discussed with our management. Our management is

seeking approval for the same. You are requested to takeup this LDP issue in next

TCC meeting.

69/III/3 02-10-2017 at

02:03 hrs

1) PGCIL (SR-I) and APTRANSCO to provide for

Line Differential Protection as both the Main

protections on 400 kV Kurnool (AP) – Kurnool (PG)

lines 1 & 2 lines.

2) APTRANSCO to furnish an action taken report

w.r.t. resolving A/R non-operation at Kurnool-AP end

for the subject trippings and configure EL for capturing

PDR operation at their 400 kV Kurnool-AP SS.

Line tripped on B-ph to ground fault. A/R was

unsuccessful at both Kurnool (AP) and Kurnool (PG)

ends.

APTRANSCO/

PGCIL (SR-I)

Tripping of 400 kV

Kurnool(PG) – Kurnool(AP)

line-2

Pending [with

PGCIL (SR-I)]

Annexure-IV

Page 5 of 48

APTRANSCO maild ated 15.12.2017:

APTRANSCO would extend support and requirements if any ,for the rectification

proposed by KPTCL.


It was noted that the original Gooty - Lingapur line got LILOed at BTPS, Alipura,

and Ragulapadu. It was also noted that Phase Discrepancy is being observed in

Ragulapadu - Alipira section only. When enquired about the same, KPTCL informed

that they would examine the issue in detail, and would inform the action lan proposed

by next PCSC-71 meeting. On this, APTRANSCO was also asked to render all help

required from their side to KPTCL.

APTRANSCO maild dated 30.01.2018:

APTransco world extend required support .

APTRANSCO maild dated 24.04.2018 & 24.05.2018 & 26.06.2018:

AP Transco would extend required support for attending, phase discrepancy issue in

ragulapadu-Alipura line by KPTCL.


To be attended by KPTCL as discussed in 75th PCSC meeting.


Phase mis match issue is to be sorted out jointly by KPTCL/ APTRANSCO/ KPCL.

Review Meeting on 20.12.2018:

PCSC forum decided that concrete action in this respect to be initiated in 2 months by

KPTCL alongwith APTRANSCO.


Pending [with KPTCL ]


KPTCL informed that the work is expected to be completed by August 2019.

Line tripped on B-Ph to earth fault. A/R was successful

at Regulapadu and breakers at Alipura end got tripped.

69/III/7 Tripping of 220 kV

Ragulapadu – Alipura line

12-10-2017 at

01:30 hrs

KPTCL and APTRANSCO to sort out issues relating

to incongruence in denoting R, Y, B phases of the

electric supply on their respective sides.

APTRANSCO/ KPTCL

Tripping of 230 kV

Thiruvalam - Chittoor line

76/II/9 1) TANTRANSCO Mail dated 29.08.2018 & 11.09.2018:

Material supplied and work to be taken up ---Pending

2) APTRANSCO Mail dated 24.09.2018:

The static relays were replaced with Numerical relay on all 220 kV feeders at 220 kV

SS chittoor.---Completed

TANTRANSCO Mail dated 11.12.2018:

Due to space constraint, the equipments could not be erected.


In view of Tiruvalam being inter-state sustation, TANTRANSCO was asked to

prvodie double-bus operation at their 230 kV Tiruvalam SS.


Pending [with TANTRANSCO]

TANTRANSCO MAIL DATED 23.01.2019 & 19.03.2019:

Feasibility for providing hybrid breaker / shifting of bays will be studied & action

will be taken. Time upto Sep 2019

TANTRANSCO MAIL DATED 13.06.2019:

1. Bus segregation will be ensured by providing bus coupler bay by extending the

existing Bus.Time line 31.12.2019.

TANTRANSCO mail dated 18.07.2019 & 26.07.2019:

1. Bus segregation will be ensured by providing bus coupler bay by extending the


Pending [with

TANTRANSCO]

TANTRANSCO/

APTRANSCO

13-06-2018 at

18:55hrs

Y-phase to earth fault occurred in line. At 230 kV

Tiruvalam end, breaker was under lockout leading to

operation of LBB protection.

1) TANTRANSCO to provide double-bus operation at

their 230 kV Thiruvalam SS.

2) APTRANSCO to replace the existing static relays

with suitable numerical relays for various line

protections at their 220 kV Chittoor SS.

Pending

[with KPTCL ]

Annexure-IV

Page 6 of 48


3). Nagzari-Bidnal PLCC link is healthy --- Completed.

1.--- Pending

2. --- Pending


1. & 3. Completed

2. Pending

KPCL mail dated 24-12-2018:

1) --- Completed

2) Proposal will be taken up for replacement of existing PZ1000 relays with new

version Numerical Line protection relays having IEC61850 shortly, after availing

necessary admnistrative approval...Pending

3) Completed

KPCL mail dated 23.01.2019:

1. Completed

2. Letter addressed to site to take up the proposal for replacement of PZ1000 line

distance relays.KPCL mail dated 23.03.2019:

1). COMPLETED


version Numerical Line protection relays having IEC61850. Prepration of

specification is under progress.

3) COMPLETED


1) & 3) Completed

2) Budgetary offer obtained for replacement of existing PZ1000 relays with new

version Numerical Line protection relays having IEC61850. Preparation of estimation

and specification is under progress.


1) & 3) Completed

2) Replacement of existing PZ1000 relays with new version Numerical Line

protection relays having IEC61850 is included in PSDF Phase-II DPR. Approval of

NLDC for DPR is awaited. Further, availing administrative approval for issue of NIT

for replacement of existing PZ1000 relays with new version Numerical Line

protection relays having IEC61850 and preparation of estimation and specification is

under progress.

Review Meeting on 27.06.2019:KPCL mail dated 16.07.2019:

1) & 3) Completed



NLDC for DPR is awaited. However, administrative approval for issue of NIT for

replacement of existing PZ1000 relays with new version Numerical Line protection

relays having IEC61850 obtained. Preparation of technical specification is under

progress.

1. SLDC/KPTCL to be pro-active in issuing necessary

directions that help in expeditious restoration of the

tripped lines based on the prevailing conditions and

grid security.

2.KPCL to implement A/R enabled on all 220 kV lines

emanating from their 220 kV Nagjheri PH, with the

help of KPTCL, by December, 2018. In the event of

non-amenability of the existing PZ1000 relays in

providing A/R feature, KPCL shall take steps to

retrofit them with suitable relays that support A/R.

3. KPTCL to restore PLCC carrier communication on

220 kV Nagjheri – Bidnal line at the earliest

220kV lines connected to Nagjheri PH got tripped due

to successive transient faults. Running Units #3 and #4

at Nagjheri got tripped on over frequency protection

operation due to loss of evacuating lines resulting in

complete outage of 220 kV Nagjheri. 220 kV Nagjheri

being the only source to 220kV Ambewadi station,

since 220kV Ambewadi Narendra line 1&2 were under

shutdown during antecedent condition, tripping of

Units at 220 kV Nagjheri resulted in the loss of supply

to 220 kV Ambewadi SS.

17-09-2018 at

14:37hrs

Complete outage of 220 kV

Nagjheri PH and 220/110 kV

Ambewadi Substation.

78/I/2 PendingKPCL/ KPTCL

Annexure-IV

Page 7 of 48


1. KPTCL I formed that SPS scheme finalisation shall be completed in one month

time --- Pending

KPCL mail dated 24-12-2018:

2) Time delay of operation is not changed. However, the external NCT is used for

REF protection against earlier internal NCT for REF, to avoid tripping due to

malopration --- Completed.


1) It shall be reviewd and Implemented by KPCL in coordination with KPTCL.

2)....Completed.


1) It shall be reviewd and Implemented by KPTCL in coordination with KPCL.

KPCL mail dated 10.05.2019 & 25.06.2019:

1) Letter addressed to KPTCL RT dated: 25.03.2019 for review and implementation

of SPS at NPH. Reply is awaited.


1. KPTCL informed that Nagjheri SPS has to be studied in the event of configuration

changes and outcome of the same will be intimated soon .KPCL mail dated 16.07.2019:


of SPS at NPH. Reply from KPTCL is awaited.

2)Completed.

TANTRANSCO Mail dated 11.12.2018:

1. TANTRANSCO: Estimate sanctioned for replacement of defective isolator status

feedback. Work under progress. ......Pending

2.Earth value of 110kV earthmat has been improved & 230kV side earthmat work

under progress. Lightning mask earthing renovation under execution............Pending

3.......Pending


Relays settings reviewed and need to be revised due to change of line length DR &

EL's of Main-1 (P444) relay configured properly. Main-2 (D60) relay to be

configured.


1 & 2). TANTRANSCO informed that Work will be completed by March 2019.

3. APTRANSCO informed that work will be completed by February 2019.


Collecting the details of adjacent feeders connected to Gummadipudi for computing

revised relay settings.


Isolator status will be ensured by March 2019

79/I/2

Multiple trippings at 220kV

Nagjheri PH

Triggering incident was B-phase fault at 230kV

Gummidipoondi Substation due to which 230kV Bus-1

Bus-bar protection operated. 230kV Gummidipoondi

Station was under single bus operation, hence

operation of Bus-bar protection resulted in tripping of

all connected elements.

31-08-2018

at 11:49 hrs

KPTCL/ KPCL1)KPTCL to examine the reasons for tripping of more

than one Unit (Units – 3 & 6) on SPS operation at

Nagjheri PH during subject trippings, and furnish a

report on the same along with remedial action taken to

PCSC forum.

2)KPCL to employ a suitable time delay of 50 – 60

msec in operation of REF protection for the GT of Unit-

2 at their Nagjheri PH.

Triggering incident was B-E fault in 220 kV Nagjheri -

Ambewadi line-1. As per the information received,

after tripping of 220 kV Naghjeri - Ambewadi line-1,

220 kV Naghjeri Ambewadi line#2 got overloaded.

This resulted in the tripping of Nagjheri Generating

Units #3 and 6 on SPS operation. At the same time,

Unit #2 got tripped on REF operation.

Pending

1) TANTRANSCO to take steps to implement multi-

bus, multi-zone operation (Double-bus operation) at

their 230 kV Gummidipooindi SS by December,

22018.

2) TANTRANSCO to check if the Gummidipoondi

substation is adequately protected from lightning-

strokes by providing requisite no. of lightning masts

and/ or earth-wire caging.

3) APTRANSCO was asked to verify & correct the

settings employed for distance protection at Sullurpeta

and configure DR’s & EL’s of all Protection Relays at

their Supllurpet SS properly for recording only the

mandated protections & digital signals.

Pending [with

TANTRANSCO]

78/II/16

TANTRANSCO/

APTRANSCO

05-10-2018 at

00:42 hrs

Complete outage of 230/ 110

kV Gummidipoondi

Substation

Annexure-IV

Page 8 of 48


3. Revised relay settings were implemented on 16/02/2019 ---Completed


New 230kV isolators have been allotted for replacement of defective isolators. Hence

time line requested upto June.2019.


1. New 230kV isolators have been allotted for replacement of defective isolators.

Hence time line requested upto Sep.2019.


1. New 230kV isolators have been allotted for replacement of defective isolators.

Hence time line requested upto Sep.2019.

2. & 3. Completed

TANTRANSCO mail dated 18.07.2019 & 26.07.2019:

1. 1New 230kV isolators have been allotted for replacement of defective isolators.

Hence time line requested upto Sep.2019

81/IV/3 Tripping of 400 kV

Warangal - Bhoopalapalli

line-2

15-12-2018 at

20:42 hrs

Line tripped at Bhoopalapalli end only and was holding

from warangal s/s. FIR, DR and EL of Bhoopalapally

were not furnished.

For the line under consideration, the following shall be

carried out by TSGENCO in coordination with PGCIL

(SR-I):

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

other signals may be ensured by testing at both the

ends.

(ii) Healthiness of PLCC system components

(hardware and software) at both ends shall be checked

and faulty components shall be repaired/ replaced.

TSGENCO/ PGCIL (SR-

I)


PGCIL-SR1: Presently WGL-Bhopalapalli-2 line PLCC Ch-1 is unhealthy same was

informed to TSGENCO for rectification. The Ch-1 is out of service from last 50 days

onwards. Both ends PLCC belongs to TSGENCO

TSGENCO mail dated 24.06.2019:

TSGENCO is cordinating with TSTRANSCO for testing of End-to-End

communication for DT/permissive & other signals; checking of Healthiness of PLCC

system components and also for replacing of faulty components .


TSGENCO informed that PLCC has to be replaced and will be done by December

2019.

Pending [with

TSGENCO]


Veeranam substation of

TANTRANSCO

11-03-2019

at 00:55Hrs

Triggering incident was Y-phase CT blast in 230kV

Tirunelvelli (Abhishekpatty) – Veeranam Ckt-1.

230kV Trirunelvelli – Veeranam Ckt-1 and 2 tripped.

Two faults were observed from the PMU plot. During

the second fault, delayed fault clearance of 400ms was

observed. As reported, other connected feeders 230kV

Veeranam – Kodikur ckt-1&2 and 230kV Veeranam –

Kayathar tripped on Zone -2 protection.

1. TANTRANSCO is recommended to submit action

plan to provide Multi-Bus operation/ Hybrid breakers

at 230kV Veeranam SS with clear timelines.

2. TANTRANSCO to revise the distance zone settings

at Tiruneveli SS for 230kV Veeranam – Tirunelveli

line to overcome the problem of relay overreach and

share the same with SRPC.

3. TANTRANSCO to take definite measures ensure

the time synchronization of relays at Tirunelveli end.

4. TANTRANSCO to submit equipment failure report

of the failed CT to CEA.

TANTRANSCO TANTRANSCO MAIL DATED 13.06.2019:

1.Provision of bus coupler breaker is not feasible due to space constaint.

2&3. Tirunelveli end maintained by PGCIL.

4. Report will be sent.

Review meeting on 27.06.2019:


2. Will be informed

3. Time synchronisation will be ensured.

4. Report will be sent.

TANTRANSCO mail dated 19.07.2019:


2&3. Tirunelveli end maintained by PGCIL.

4. Report sent to CEA.

Pending[PGCIL-

SR-II]

79/I/2 Triggering incident was B-phase fault at 230kV

Gummidipoondi Substation due to which 230kV Bus-1

Bus-bar protection operated. 230kV Gummidipoondi

Station was under single bus operation, hence

operation of Bus-bar protection resulted in tripping of

all connected elements.

1) TANTRANSCO to take steps to implement multi-

bus, multi-zone operation (Double-bus operation) at

their 230 kV Gummidipooindi SS by December,

22018.

2) TANTRANSCO to check if the Gummidipoondi

substation is adequately protected from lightning-

strokes by providing requisite no. of lightning masts

and/ or earth-wire caging.

3) APTRANSCO was asked to verify & correct the

settings employed for distance protection at Sullurpeta

and configure DR’s & EL’s of all Protection Relays at

their Supllurpet SS properly for recording only the

mandated protections & digital signals.

Pending [with

TANTRANSCO]

TANTRANSCO/

APTRANSCO

05-10-2018 at

00:42 hrs

Complete outage of 230/ 110

kV Gummidipoondi

Substation

Annexure-IV

Page 9 of 48


Hubli substation of KPTCL

and 220kV

Nagjheri Power station of

KPCL

10-04-2019

at 18:09Hrs

Y and B-phase earth isolator switch blades of 220kV

Hubli-Bidnal ckt-1, got closed due to failure of locking

mechanism during heavy wind and rain

conditionsresulting in bus fault. Bus bar protection

operated and all connected elements tripped. There was

complete loss of supply at 220kV Hubli station since

the station was on single bus operation. At thesame

time, 220kV Nagjheri-Ambewadi ckt-1 and 220kV

Nagjheri – Bidnal tripped on overcurrent

protection. Since 220kV Nagjheri – Ambewadi ckt-2

and 220kV Nagjheri-Kodasalli ckt-1 &2 wereunder

shutdown in the antecedent due to maintenance,

running units #1,4,5 and 6 tripped due to

loss of evacuating lines. This resulted in complete loss

of supply at 220kv Nagjheri station.

1. KPTCL is recommended to revise the SPS at

Nagjheri, (to accommodate a new condition with high

flow and low time delay) in consultation with SRPC

and SRLDC.

2. KPCL in coordination with KPTCL is recommended

to provide at least one main protection as carrier aided

three zone distance protection on the 220kV lines

emanating from Nagjheri GS.

KPTCL/ KPCL KPCL mail dated 25.06.2019:

2) Carrier aided protection is enabled on all 220kV lines emanating from NPH

___Completed


1. KPTCL informed that Nagjheri SPS has to be studied in the event of configuration

changes and outcome of the same will be intimated soon


1. under progress

2. Completed

Pending

83/II/9 Tripping of 400 kV

GUTTUR - NARENDRA -1

10-03-2019 at

18:03hrs

Line tripped on operation of overvoltage stage-1

protection at Guttur end and DT received at Narendra

end. Voltages at Guttur end: Vr-254kV, Vy-252kV,

Vb-246kV. As per voltage grading, 400kV Guttur

Narendra line-2 should trip first.

PGCIL (SR-II) to submit action plan regarding

replacement of CT’s for 400Kv Guttur Narendra line -

1 at Guttur end. PGCIL (SR-II) to sort out the time

sync issues in DR and EL at Narendra end.

PGCIL (SR-II)/ KPTCL PGCIL (SR-I) mail dated 07.06.2019:

Line belongs to PGCIL(SR-2)


PGCIL(SR-II) informed that R & Y ph CVT replaced on 25.05.2019. Time

syncronisation has to be attended by KPTCL.

Pending

23-03-2019 at

04:41 hrs

24-03-2019 at

02:32 hrs

25-03-2019 at

01:19 hrs


NCTPS Generating Station

of TANGEDCO

18-05-2019 at

04:39 hr.

Triggering incident was Y phase to Earth fault in 220

kV NCTPS Tondiarpet line-2. Due to mal-operation of

LBB protection (of Tondiarpet line-2) at NCTPS end,

all the connected elements of bus zone-3 got tripped.

Due to loss of evacuating lines, running units at

NCTPS unit#1 and 2 got tripped.

1.TANTRANSCO may take immediate measures to

attend the problem in LBB wiring that is extending trip

during A/R within one month.

2. TANTRANSCO is recommended to send a detailed

report regarding the A/R status (availability

/enabling)on all lines emanating from 230kV NCTPS

GS and enable A/R in all lines emanating from 230kV

NCTPS GS.

3.TANGEDCO in coordination with TANTRANSCO

may take definite measures to ensure time

synchronization of all relays with GPS signal at

NCTPS end and remote ends at the earliest.

4. It was also suggested that possibility of backing

down of generation, in the event of unavailability of

many feeders, in particular when radial feeders only

are in service, may be looked at.

TANGEDCO/

TANTRANSCO


1 & 2.Inbuilt LBB function will be enabled in the new distance relays.

3. will be ensured.

4.230kV Kilpauk was operated radially for avoid overloading in the adjacent feeders

due to cable fault in the area.Normally all feeders are operated as grid feeders.

Pending

Pending [ with

APGENCO]

Tripping of 400kV

Krishnapatnam – Nellore ckt-

1

Feeder tripped due to severe tracking on line insulator

stacks.

1. APGENCO to inform PCSC forum the following:

Status of A/R in 400kV Krishnapattnam – Nellore

line-1 at Krishnapattanam end, if A/R is not enabled

APGENCO shall implement 1-ph ‘lead-follow’ A/R

scheme at Krishnapattanam.

The reason for tripping of Unit-2, along with the line

tripping on 24.03.2019.

2. APGENCO in consultation with APTRANSCO to

explore the possibility of providing Line Differential

Protection (LDP) for the line.

3. APTRANSCO is recommended to replace the

insulators of the line with polymer insulators.

83/II/17 APGENCO/

APTRANSCO


3. Line Insulator stacks were replaced with SRC insulators at location Nos.4,5,6 for

Krishanpatnam-1 on 26/03/2019 and Krishanpatnam-2 on 27/03/2019.--------------

Completed.


1. APGENCO representative did not attend the meeting. APGENCO is requested to

furnish the status at the earliest.

Annexure-IV

Page 10 of 48


NCTPS Generating Station

of TANGEDCO

19-05-2019 at

22:44 hr.

230kV lines connected to NCTPS got tripped due to

fault in lines. Running units#1,2 and 3 at 230kV

NCTPS also got tripped due to loss of evacuating lines.

1. TANGEDCO in coordination with TANTRANSCO

to take definite measures to ensure time

synchronization of all relays with GPS signal at

NCTPS end and remote ends at the earliest.

2.The PCSC noted frequent jumper cut/conductor snap

instances in the area, of late; accordingly, it was

suggested to have adequate condition monitoring and

preventive maintenance measures.

3.TANTRANSCO to communicate

(i) the schedule of replacement of balance porcelain

insulators with polymer insulators in evacuation lines

from NCTPS.

(ii) schedule of insulator washing

4.NCTPS /TANGEDCO to inform regarding house

load operation capability of Generators at NCTPS.

TANGEDCO/

TANTRANSCO


2& 3.wedge connector have been provided in order to avoid jumbercut.

4. Replacement of porcelain insulators by polymer insulatos in all 230kV & 400kV

feeders in North Chennai area has been completed

Pending

84/II/4 Tripping of 230kV Sulurupet-

Gumudipoondi line

11-04-2019 at

16:05 hr.

Triggering incident was B-N fault in 230kV

Gummudipoondi-NCTPS line. 230kV Sulurupet -

Gummudipoondi line tripped on operation of zone-2

distance protection at Sulurpet end and reverse zone

protection at Gummudipoondi end.

1.TANTRANSCO to check the resistive and reactive

reach settings of 230kV Gummudipoondi-NCTPS line

at Gummidipoondi end.

2. APTRANSCO to ensure time synchronization of

DR and EL at Sulurupet end. Also in coordination with

TANTRANSCO sort out the time synchronization

issue in 230kV Sulurupet-Gumudipoondi line.

3. TANTRANSCO to check the SOTF settings at

Gummidipoondi end for 230kV Gummudipoondi-

NCTPS line .

TANTRANSCO/

APTRANSCO


2. GPS not available at 220KV Sullurpet SS.Manually set the timing on 29/07/2019 -

- Completed


1. & 3. Will be reviewed

Pending [ with

TANTRANSCO]

84/II/19 Tripping of 400/220 kV ICT-

1 atCuddapah

03-05-2019 at

23:39 hr.

ICT-1 Tripped on operation of APTRANSCO 220 kV

Bus Bar relay (96 trip relay). Fault reported in 220 kV

Cudappah-Renigunta line

1. PGCIL (SR-I) to submit the high set settings of

ICT’s at Cuddapah. Since the static relay in which

high set is enabled has no provision to provide time

delay, ICT high set shall be enabled from numeric

relay and sufficient time delay shall be provided for

highset operation.

2.APTRANSCO to check the Busbar operation at 220

kV Cuddapah SS and submit a report regarding the

same.

3. PGCIl (SR-I) to inform the methodology adopted for

calculating high set settings of ICT’s. Also due to

changes in system configuration at Cuddapah in recent

future revision of set points shall be taken up.

PGCIL (SR-I)/

APTRANSCO


2. The 220KV GE make B90 type Bus Bar relays tested on 23/07/19 and found

healthy. The report submitted vide mail dated 29.07.2019 - Completed

Pending [ with

PGCIL (Sr-1)

84/II/22 Tripping of 400kV

Khammam-Mamidapalli line-

1

09-05-2019 at

02:40 hr.

Line tripped on mal-operation of Reactor differential

protection and DT sent to Khammam.

TSTRANSCO in coordination with PGCIL (SR-I) to

ensure time synchronization of relays at Mamidapalli

end with Khammam end in 6 months’ time.

TSTRANSCO/ PGCIL

(SR-I)

Yet to be informed Pending

Annexure-IV

Page 11 of 48

84/II/29 Frequent tripping of 220 kV

KTPS –Lower Sileru line

01-05-2019 at

16:04 hr.

04-05-2019 at

14:48 hr.

05-05-2019 at

11:29 hr.

06-05-2019 at

13:14 hr.

09-05-2019

at13:58 hr.

12-05-2019

at11:10 hr.

15-05-2019

at21:05 hr.

26-05-2019

at15:36 hr.

29-05-2019

at21:26 hr.

B-N FAULT

B-N FAULT

B-N FAULT

B-N FAULT

R-N FAULT

R-B FAULT

R-B FAULT

B-N FAULT

R-B FAULT

It was noted that no representative of APGENCO

attended the meeting.

For the subject line, the following shall be carried out

by TSGENCO in co-ordination with APGENCO:

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

other signals may be ensured by testing at boththe

ends.

(ii) Healthiness of PLCC system components

(hardware and software) at both ends shall be checked

and faulty components shall be repaired/ replaced.

APGENCO in coordination with TSGENCO to

ensure frequent patrolling and proper maintenance of

ROW by attending all tree clearance issues.

APGENCO/

TSGENCO


85/II/3 Tripping of 400kV Kurnool-

Srisailam line

17-05-2019 at

14:10 hrs

line tripped only at Srisailam end on Zone-3 distance

protection operation during Y phase to B phase fault in

220kV NarnoorSomayajulapalli line-1

1. TSGENCO is recommended to modify the PSL

logic (Srisailam end to trip for faults occurring in Zone-

2 and Zone-3 with respective time delays except for

PUR scheme if adopted ) in 1 month time to avoid

occurrence of any such unwarranted trippings in future.

2. APTRANSCO to ensure time synchronization of

relays at 220kV Somayajulapalli SS.

TSGENCO/

APTRANSCO


85/II/14 Tripping of 230kV Theni-

Sabarigiri line

29-05-2019 at

18:39 hrs

3 phase to earth fault occurred in line. Tripped on

ground over current protection 67N at Sabarigiri and

Zone-2 at Theni end.


by TANTRANSCO in coordination with KSEBL:

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

signals may be ensured by testing at both the ends.

(ii) Healthiness of PLCC system components (

hardware and software) at both the ends shall be

checked and faulty components shall be repaired/

replaced .

TANTRANSCO/

KSEBL


85/II/17 400 kV Ghani – Narnoor line-

1, 400 KV Jamalamadugu-

Kurnool line-1, 765/400 kV

ICT-1&2 at Kurnool

30-05-2019 at

00:48 hrs

Triggering incident was Y-ph to B-ph fault in the

400kV NarnoorJammalamadugu line-1 & 2 due to

falling of Y-ph CVT jumper on B-ph during heavy

wind. At the same time, 400kV GhaniNarnoor tripped

only at Ghani end on operation of Zone-1 distance

protection. 765/400 kV ICT-1 & 2 at Kurnool PG also

got tripped on HV side Directional Overcurrent (DOC)

protection.

1. APTRANSCO is recommended to sort out the issues

with their distance protection relay (7SA522) which

maloperated and caused unwarranted tripping of

400kV Ghani – Narnoor line-1. The time

synchronization of relays at Ghani end also shall be

ensured.

2.PGCIL (Sr-1) is recommended to submit a detailed

report regarding operation of ICT Buchholz relay for

through fault conditions along-with remedial measures

suggested by OEM.

APTRANSCO/ PGCIL

(SR-1)


85/II/20 Tripping of 220kV Idukki-

Udumalpet line

05-06-2019 at

15:13 hrs

Triggering incident was R-Y-Earth fault in the

line. Carrier aided protection not operated at

Udumalpet end.


by TANTRANSCO in coordination with KSEBL:

(iii) End-to-end testing for DT/ permissive & other


(iv) Healthiness of PLCC system components (



replaced .

KSEBL/

TANTRANSCO


85/II/26 Tripping of 400kV Vemagiri-

GMR line-1&2

14-06-2019 at

09:33 hrs

Line-1 tripped on Y-Phase to earth fault due to Y-

Phase LA failure at Vemagiri end. Line-2 tripped at

GMR end only

1. APTRANSCO is recommended to submit

Equipment failure report (LA failure) to CEA.

2.GMR is recommended to submit a report regarding

tripping of 400kV Vemagiri-GMR line-2 at GMR end

along-with the related tripping files.

APTRANSCO/ GMR Yet to be informed Pending

Annexure-IV

Page 12 of 48

02-06-2019

at 15:30 hrs

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

was successful at Lower sileru end. A/r is not enabled

at KTPS.

02-06-2019 at

15:30 hrs


was successful at Lower sileru end. A/r is not enabled

at KTPS.

09-06-2019 at

11:58 hrs

B-phase to earth fault occurred in line. Zone-2

operated at KTPS and Earth fault at Lower sileru.

Suspected high resistance fault.

12-06-2019 at

14:23 hrs

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

was successful at Lower Sileru end. A/r is not enabled

at KTPS

85/IV/2 Tripping of 400kV

Khammam-Mamidapally line-

1

27-05-2019 at

18:16 hrs

Line tripped only at Mamidapally end due to suspected

PLCC maloperation


by TSTRANSCO in coordination with PGCIL(SR-I):

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


(ii)Healthiness of PLCC system components (



replaced .

TSTRANSCO/ PGCIL

(SR-I)


85/IV/5 Tripping of 400kV Warangal-

Bhoopalapalli line-1

&BoopalppalliChandlapur

line-1

08-06-2019 at

1:35 hrs

400kV Warangal-Bhoopalapalli line-1 line tripped

only at Boopalappalli end on OV st-1 protection

operation and DT was not sent to Warangal end due to

failure of both PLCC channels. 400kV

BoopalppalliChandlapur line-1 tripped at Boopalpalli

end due to DT Receive


by TSTRANSCO in coordination with TSGENCO

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


(ii)Healthiness of PLCC system components (



replaced .

TSGENCO/

TSTRANSCO


Andhra Pradesh

ATRANSCO in coordination with TSTRANSCO to

ensure frequent patrolling and proper maintenance of

ROW by attending all tree clearance issues.

APTRANSCO/

TSTRANSCO

Yet to be informed Pending85/II/32 220kV Lower Sileru-KTPS

line

Annexure-IV

Page 13 of 48





MEPL line

18-07-2016

at 19:05 hrs






APGENCO to furnish a report on the remedial action

implemented w.r.t. overreaching of Krishnapatnam end

distance relays during the tripping of 400 kV Nellore

(PG) - NPS line-1

APGENCO Review Meeting dated 19.12.2017:

It was noted that no APGENCO representative had come to attend the meeting.

APGENCO Mail dated 19.12.2017:

Procurement of relays is under progress

Pending

82/III/8 Tripping of 400kV VTPS-

SURYAPET-1

10-02-2019

at 13:20 hrs

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

was successful at Suryapet and breakers got tripped at

VTPS end


attended PCSC-82 meeting. APGENCO to furnish a

detailed report on tripping event bringing out reasons

for A/R non-operation at VTPS end along with

remedial action taken to PCSC forum.

APGENCO Review Meeting on 27.06.2019:



Pending

82/III/9 Tripping of 400kV VTPS-

SURYAPET-1

15-02-2019

at 14:36 hrs


was successful at Suryapet and breakers got tripped at

VTPS end


attended PCSC-82 meeting. APGENCO to furnish a

detailed report on tripping event bringing out reasons

for A/R non-operation at VTPS end along with





Pending

83/II/20 Tripping of 220kV VTS-

Talapalli ckt-3 and

Generating Units#1,2,3,4,5

& 6 at VTS.

01-04-2019 at

22:58hrs

220kV VTS – Talapalli ckt-4 was under maintenance.

While restoring the feeder, 220kV VTS – Talapalli ckt-

3 tripped on Zone-1 distance protection due to B-N

fault. At the same tine VTS unit# 1 & 2 tripped on

Loss of fuel and Generators 3,4,5&6 tripped on

Generator Negative phase sequence protection.

1. APGENCO is recommended to revise the time

delay of Negative Phase sequence protection operation

in consultation with OEM.

2. APGENCO is also recommended to look into the

Overcurrent Protection settings of Buscoupler, so as to

reduce its time delay of operation in case of faults on

Transfer Bus.




Pending

83/III/8 Tripping of 400 kV VTPS -

Nellore

24-03-2019 at

12:46hrs

Feeder tripped on Y -N Fault. Auto reclose operated at

Nellore end but not operated at VTPS end.

APGENCO is recommended to submit a detailed

report regarding the reason for A/R being kept

disabled and the Remedial Measure taken for the same.




Pending

84/II/9 Tripping of 220kV Bus 2 and

connected elements at 220kV

Gazuawaka Substation.

17-04-2019 at 5:40 hr.Triggering incident was Y-phase to earth fault in

220kV Gazuwaka Bus-2. This resulted in tripping of

220 kV elements and 400/220 kV ICT-2

1. APTRANSCO to submit a detailed report

regarding the subject tripping at 220 kV Gazuawaka

Substation along with the remedial measures taken.

2. For all lines emanating from Gazuwaka SS, RTV

coating shall be taken up.

APTRANSCO APTRANSCO mail dated 30.07.2019:

1. The report submitted vide mail dated 29.07.2019 -- Completed

2. Pending

Pending


2 at Ghani substation

21-05-2019 at

15:13 hrs

ICT-2 tripped on LV Earth fault protection. 400kV

Ghani-Narnoor line-1 had tripped on B-phase to earth

fault.

APTRANSCO is recommended to send a detailed

report regarding non-availability of Main CB (Main

CB was already in tripped condition in antecedent

condition) during the tripping and non-attempt of auto-

reclosure by Tie CB at Ghani end.

APTRANSCO Yet to be informed Pending

85/II/27 Multiple tripping at 220kV

Nunna substation

16-06-2019 at

06:16 hrs

Triggering incident was failure R phase CT of

220/132kV transformer (connected to 220kV Bus-2) in

220kV Nunna station. Bus-2 bus bar protection

operated resulting in tripping of elements connected to

220kV Bus-2. 2.63 Seconds later a 2nd fault occurred

in Bus-1 due to fault getting extended from Bus-2 CT

failure which inturn resulted in tripping of elements

connected to 220kV Bus-1

1.APTRANSCO is recommended to submit Equipment

Failure Report regarding the failed CT to CEA.

2.APTRANSCO to sort out time synchronization

issues in 220kV Nunna SS.


Annexure-IV

Page 14 of 48

85/III/1 Tripping of 400kV Ghani-

Narnoor line-1

21-05-2019 at

15:11 hrs


was not successful as fault was persistent in nature.

Fault was cleared in zone-2 time during A/r attempt

APTRANSCO is recommended to send a detailed

report regarding non-availability of Main CB (Main

CB was already in tripped condition in antecedent

condition) during the tripping and non-attempt of auto-

reclosure by Tie CB at Ghani end.


85/III/4 Tripping of 400kV

Talarichevu - Jamalamadugu

ckt-1

22-05-2019 at

19:21 hrs

R phase to Earth fault in the line. At Jammalamadugu

end A/r operated and line tripped due to persistent

fault. Main CB A/r not attempted at Talarichevu

APTRANSCO is recommended to submit a report

regarding non-attempt of A/R by Main CB at

Talarichevu end of 400kV Talarichevu -

Jamalamadugu ckt-1.


Annexure-IV

Page 15 of 48

82/II/1 Tripping of 400kV KTPS VI-

KTPS VII

05-01-2019

at 10:17hrs

Line tripped at KTPS VI end due to suspected mal-

operation of over-voltage protection. Line was in

service from KTPS VII., BUS CVT secondary R

PHASE got grounded at KTPS VI

1) TSGENCO to configure OVR_start and

OVR_tripin EL at KTPS-VI end and sent a report after

completion of works related to DT communication

channel between KTPS-VI and KTPS-VII

TSGENCO TSGENCO mail dated 24.06.2019:

The issue is referred to M/s BHEL ( EPC vendor ) and the study on feasibility for

providing the communication with the existing available system is under process and

will be completed during the availability of next shutdown.


TSGENCO informed that the recommendations will be completed in September 2019

Pending

83/III/6 Tripping of 400kV Julurpadu

- Manuguru line-2

14-03-2019 at

06:10:00

Triggering incident was R-ph fault in the line. At

Julurpadu end, fault was sensed in Zone-2 and carrier

was received but due to DT Receive from manuguru

end, A/r not operated and line got tripped. FIR, DR and

EL of Manuguru end are not available.

It was noted that no representative of TSGENCO

attended the meeting. TSGENCO is recommended to

submit a report on the tripping and to furnish

equipment failure report to CEA.

TSGENCO TSGENCO mail dated 24.06.2019:

FIR, DR and EL was uploaded in SRLDC website.Trip Report was also submitted.


TSGENCO informed that Equipment failure report will be sent to CEA.

Pending

84/II/28 Frequent tripping of 220 kV

KTPS –Nunna line

05-04-2019 at

12:55 hr. B-N

FAULT

15-04-2019 at

13:20 hr. Y-N

FAULT

16-04-2019 at

14:04 hr. B-N

FAULT

22-04-2019 at

14:13 hr. R-N

FAULT

23-04-2019 at

13:31 hr. R-N

FAULT

04-05-2019 at

14:40 hr. B-N

FAULT

09-05-2019 at

14:31 hr. B-N

FAULT

05-05-2019 at

13:03 hr. B-N

In 155thOCC meeting of SRPC, APTRANSCO

informed that the tripping was due to clearance issues

in the ROW caused by mango tree. It was cleared and

issue was rectified. However, frequent tripping of line

is still persistent.

1. TSGENCO to check the non-operation of carrier

aided trip, when fault is detected at KTPS end in Z-2

and carrier is also received, and submit a report

regarding the same.

2. TSGENCO and APTRANSCO to ensure that

ROW is cleared periodically.

3.APTRANSCO & TSGENCO may consider raising

the height of towers if the line is planned to be used in

future.

4.TSGENCO to consider replacement of old

pneumatic CB’s at KTPS if 220kV KTPS- Nunna line

is planned to be used in future.

TSGENCO Yet to be informed Pending

Telangana

Annexure-IV

Page 16 of 48


2 at Gajwel

11-04-2018 at

5:50 hrs

400/220 kV ICT-2 at Gajwel tripped on mal-operation

of Buchholtz relay.

1). TSTRANSCO was asked to keep the ICT and its

mechanical protections under observation for detecting

any slippages.

2). TSTRANSCO was also asked to configure

capturing of mechanical protections of ICT’s in the

respective relay’s/ station’s event logger.

TSTRANSCO TSTRANSCO mail dated 20.06.2018:

1. Mechanical protections of ICTs is under observation. --- Completed

2.New relays are available at site and will be commissioned by 2nd week of August-

2018. The mechanical protection of ICTs will be configured in the new relays ----

Pending


2. New relays will be commissioned by end of November-2018 and the Over Voltage

settings will be implemented after commissioning in new relays ----Pending


2. New relays will be commissioned by end of January-2019 and the mechanical

protections of ICTs will be configured in the new relays ----Pending

Pending

84/II/1 Tripping of 400kV Srisailam-

Dindi line-1 and 400kV

Mamidapalli-Dindi line-1

06-04-2019 at

17:39 hr.

400kV Mamidapally Dindi line-1 tripped on R-phase

to earth fault. 400kV Srisailam-Dindi line-1 tripped on

operation of cable differential protection at Srisailam

and direct trip was sent to Dindi.

1.TSTRANSCO to ensure time synchronization of DR

and EL at Mamidapalli end and Dindi end. Also in

coordination with TSGENCO sort out the time

synchronization issue in 400kV Srisailam – Dindi line-

1. 2.TSTRANSCO to ensure that A/R dead-time

is maintained as 1 sec uniformly at all Stations.

TSTRANSCO Yet to be informed Pending


2 and 3 at Dichipalli

Substation

22-04-2019 at

17:22 hr.

ICT#2 and 3 got tripped on suspected mal-operation of

LV earth fault relay during fault in 220 kV Dichpally-

Medaram feeder

1 .TSTRANSCO to ensure directional settings for ICT

earth fault protection and to ensure coordination

between line and ICT DEF protection.

2.TSTRANSCO to investigate the reason for non-

operation of LBB protection of 220 kVDichpally-

Medaram line while breaker lockout at Dichipalli SS

occurred.

3. TSTRANSCO to perform condition monitoring of

CB’s regularly to ensure sufficient air pressure for

proper CB operation.


84/II/27 Multiple tripping at 220 kV

Ghanapur station

27-05-2019 at

02:04 hr.

Triggering incident was failure of B-phase CT of bus

coupler of Bus-2. Bus bar protection of 220 kV Bus-2

operated resulting in tripping of all elements connected

to Bus-2.

1.TSTRANSCO is recommended to submit

Equipment failure report to CEA regarding the blast

CT.

2.TSTRANSCO to inform if any old CTs exist in

Ghanapur SS and ensure healthiness of the same to


84/III/4 Tripping of 400kV

Uravakonda - Veltoor ckt-1

13-04-2019 at

18:36 hr.

Y-phase to ground fault. Auto reclose didnot operate at

Veltoor end due to maloperation of STUB protection

1. TSTRANSCO to submit a report regarding the error

in PSL logic that led to the subject tripping along with

Remedial Measures taken.

2. TSTRANSCO to submit a report after checking mal-

operation of STUB protection on P444 relay.



3at Mamidapalli

21-05-2019 at

20:43 hrs

ICT tripped on PRV-1 indications due to ingress of

moisture into the relay

TSTRANSCO is recommended to ensure proper

sealing of PRV by providing suitable canopy to

prevent spurious operation of the same due to ingress

of moisture.


85/II/25 Tripping of 400kV KTPS-

VII - Julurupadu Line-2 &

tripping of 400/220kV ICT-

1&2 at Julurupadu substation

10-06-2019 at

8:22 hrs

Y-phase to earth fault occurred in 400kV KTPS-VII -

Julurupadu Line-2. Operation of over-voltage stg-2

resulted in tripping of line. 400/220kV ICT-1&2 at

Julurupadu on operation of over flux protection.

1.TSTRANSCO is recommended to check the v/f

settings of ICT-2 at Julurupadu since ICT-1 & 2

tripped at different time ( 3mins difference).

2.DGA analysis of ICT-2 shall be carried out to ensure

healthiness of ICT owing to very high voltage and the

tap position of ICT-2 also to be checked.


Annexure-IV

Page 17 of 48

85/III/12 Tripping of 400KV-

Maheshwaram PG-

Mahbubnagar line-1

06-06-2019 at

19:18 hrs

Y phase to Earth fault in the line. A/r not operated at

Mahbubnagar

TSTRANSCO is recommended to submit a report

regarding non-attempt of A/R at Mehaboobnagar with

Remedial measures taken


Annexure-IV

Page 18 of 48

Mail received on 21-10-2015:

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

periodically during AOH works of lines along with other protections.

2) Completed.

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

under review.

Mail recieved on 23-11-2015:

1) Completed

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

High speed manual heavy duty change over switch of sufficient current capacity will

be retrofitted to all feeders at 220kV station and same will be operated manually

during changeover of feeder by one bus to the other and this arrangement may Status received vide KPCL mail dated 14.12.2017:

3) DPR for implementation of Two Bus operation for 220kV bus system has been

prepared and proposal is placed for funds from PSDF. After the approval of the DPR,

the work is proposed to be taken up.


3) KPCL informed that DPR for implementation of Two Bus operation for 220kV bus

system has been prepared and proposal is placed for funds from PSDF. After the

approval of the DPR, the work is proposed to be taken up. Time frame requested for

is 2 yrs.


3) Work proposed to be taken up under PSDF. Approval from Nodal agency is

awaited. However, arrangements have been made to issue NIT.


KPCL informed that Tender would be floated in 1 month and work would be

completed in 2 years.


Tender would be floated in 1 month and work would be completed in 2 years.


Arrangements have been made to issue NIT and Tender for the work proposed to be

floated during May- 2019.


NIT will be issued during May- 2019.


1. & 2. Completed

3) Preparation of technical specification is in progress. NIT will be issued during July-

2019.


KPCL informed that timeline for completion of work is December 2019.


1. & 2. Completed

3) Preparation of technical specification is in progress. NIT will be issued during July-

2019. timeline for completion of work is December 2019.

Karnataka

46/II/21 Trippings at 220kV Raichur

TPS

07-06-2015 at

01:35 hrs

1. KPCL to check the operation of anti-pumping relay

on 220 kV side and keep it in healthy condition.

2. KPCL to provide manual reset to the 220 kV side

master trip relay.

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

under normal operation, and should go for single bus

operation only during emergencies.

KPCL Pending

Annexure-IV

Page 19 of 48

Status received vide KPCL mail dated 10.07.2017:

1. (ii) Hot line water washing stopped and off line water washing is carried out

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

Completed

1. (iii) Silicon coating for Unit#8 main & tie breakers carried out in Sep'16 and same

is under observation. Till today in order and good condition. For remaining breakers,

since it is big order, approval for the same is under process. --- Pending

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

protection feature will be enabled (if available) in the numerical relays which will be

retrofitted in phased manner during R&M works.


1.(i) --- Pending

1. (ii) Hot line water washing stopped and off line water washing is carried out

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

Completed

1. (iii) Silicon coating for Unit#8 main & tie breakers carried out in Sep'16 and same

is under observation. Till today in order and good condition. For remaining breakers,

since it is big order, approval for the same is under process --- PendingReview Meeting dated 19.12.2017:

1 (iii) As upgradation of 400kV switchyard equip's to be taken under PSDF funds,

Silicon rubber coating for breakers is deffered till then. --- Pending

2. Replacement by Num relay for Units - 5,6 & 7 completed in the month of Oct-

2017. Main-I is Seimens make and Main-II is ABB make. --- Pending


2. Replacement of Numerical relays for Units-5, 6 & 7 have been completed.

Referred to OEM for providing the Breaker flashover protection for all the breakers.KPCL mail dated 23.03.2019:

1) (i) & (iii)- Arrangements have been made to issue NIT and Tender for the work

proposed to be floated during May- 2019.

2) Reply is awaiting from OEM to implement the Breaker flash over protection in the

Numerical relays in 400KV station. & Being discussed with other utilities.

It is requested to furnish Necessary logic and settings to implement the breaker

flashover protection


1) (i) & (iii)- NIT floated on 01.03.2019



It is requested that SRPC may suggest/furnish reference of necessary logic and

settings to implement the breaker flashover protection.


1) (i) & (iii)- NIT floated on 01.03.2019. Cover-I opened. Technical evaluation is in

progress. Approval from Nodal Agency is awaited.



It is requested that SRPC may suggest/furnish referenc of necessary logic and Review meeting on 27.06.2019:

SRPC informed that referenc of necessary logic and settings to implement the breaker

flashover protection will be shared soon.


1) (i) & (iii)- NIT floated on 01.03.2019. Cover-I opened. Technical evaluation is in

progress. Approval from Nodal Agency for PSDF funds is awaited.

2) As confirmed during 84th PCSC meeting, SRPC may suggest/furnish referenc of

necessary logic and settings to implement the breaker flashover protection. reply in

this regard is awaited.

54/II/9 PendingKPCL 1.KPCL to undertake the following remedial measures

to avoid breaker flashovers:

(i) Replacing all porcelain insulators with composite

insulators

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

insulators on regular basis.

(iii) Applying Room Temperature Vulcanizing (RTV)

Silicone high voltage insulator coatings to all bus-

connected ceramic insulators of equipment like CT,

PT, CB, Isolators etc.

2.KPCL to take steps to provide dedicated breaker

flashover protection to all breakers at Raichur TPS at

the earliest.

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

Unit-4 got tripped on operation of Generator

Differential, Reverse power & LBB protection.

Operation of LBB protection led to tripping of BUS-2

at RTPS

13-04-2016 at

21:12 hrs

Tripping of 400kV Raichur

TPS

Bus-2

Annexure-IV

Page 20 of 48

Status received vide KPCL mail dated 10.07.2017 & 14.12.2017:

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

scheme for tripping of one bus during LBB/fault and maintaining the other bus intact

by tripping B/C breaker will be taken up in R&M works.


3) KPCL informed that DPR for implementation of Two Bus operation for 220kV bus

system has been prepared and proposal is placed for funds from PSDF. After the

approval of the DPR, the work is proposed to be taken up. Time frame requested is 2

yrs.

KPCL mail dated 20.12.2018 & 23.01.2019:

Work proposed to be taken up under PSDF. Approval from Nodal agency is awaited.

However, arrangements have been made to issue NIT.


NIT will be issued during May- 2019.


Preparation of technical specification is in progress.

NIT will be issued during June/July- 2019.

Review meeting on 27.06.2019:KPCL mail dated 16.07.2019:

NIT will be issued during July- 2019. Time line for completion of work is Dec-2020.

Timeline?15-04-2016 at

15:36 hrs

PendingKPCL In view of the availability of two buses along with

healthy bus-coupler at 220 kV RTPS, KPCL is

recommended to put in service the double-bus

operation at 220 kV RTPS by suitably distributing

loads within 15 days.

During testing of retrofitted distance protection in

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

extended to Bus trip. This resulted in tripping of 220kV

bus at RTPS and all connected 220 kV elements. Unit-

4 which is connected to 400 kV Bus got tripped due to

tripping of Station Utility Transformer that is

connected 220 kV bus

Tripping of Units at 220 kV

Raichur TPS

54/II/13

Annexure-IV

Page 21 of 48


1. All logics checked and found normal. LBB timing checked and found 200msec as

per KPTCL MRT recommendation. - Completed

2. Work Under Progress ---- Pending

3. New GPS System commissioned along with new numerical and synchronised with

GPS system - Complied

4. Work Under Progress ---- Pending

Status received vide mail dated 14.12.2017:

1),3),4) Completed

2. Auto Start of DG set is taken up --- Pending


2. KPCL informed that for AMF of DG, Scheme prepared & material procurement

under process. The AMF scheme will be implemented in January 2018. --- Pending

3. The GPS system commissioned on Nov 2016 & all the numarical relay time

synchronised with GPS ---- Completed


AMF panel procurement under progress.

KPCL mail dated 20.1.2.2018:

2. AMF scheme implementation is included in the work ''Replacement common

auxiliary panel with latest technology SCADA compatibility system'' . Availing Review Meeting on 21.12.2018:

KPCL informed that Tender for the work would be floated by January 2019 and work

would be completed in 1 year.


1) Completed.

2) Tender for the work would be floated by February 2019 and work would be

completed in 1 year....Pending

3) Completed.

4) Tender for the work would be floated by Feb, 2019, and work would be completed

in 1 year....Pending

KPCL mail dated 23.03.2019:Review meeting on 27.06.2019:

.1 & 3) Completed.

4) Tender published on 21.06.2019 and time line in June 2020.

2. tender has to be issued. Timeline requested upto December 2020.


1 & 3) Completed.

2 ) NIT will be issued during Aug-2019.

4) Tender published on 21.06.2019. Time line for completion of Work is Dec-2020.


Numerical Generator protection relay replacement proposed to be taken up alongwith

SCADA work.


Will be taken up along with SCADA work. NIT to be issued on Jan-2019


KPCL informed that Tender for the work would be floated by March, 2019, and work

would be completed in 1 year.


Tender for the work would be floated by February-2019 and work would be

completed in 1 year.


Tender for the work proposed to be floated during May- 2019 after model code of

conduct and work would be completed in 1 year


Tender will be floated during 3rd week of May- 2019.


Tender published on 21.06.2019.


06-10-2017 at

22:22 hrs

Tripping of 220 kV Kaiga-

Kadra line-1

PendingKPCL1) KPCL to check settings of LBB protection in all

relays from which it was implemented, and ensure that

their configuration, logic, and timing are in order at

their 220 kV Kadra PH.

2) KPCL to furnish details regarding the existing LT

auxiliary supply arrangement at their 220 kV Kadra

PH, and take steps to provide a suitable Auto-Main-

Fail (AMF) panel for DG set to effect its auto-starting

in case of failure of LT supply.

3) KPCL to ensure time-sync of all relays (DR’s &

EL’s) with GPS at their 220 kV Kadra PH.

4) KPCL to provide stand-alone Event Logger at their

220 kV Nagjheri PH.

LBB of 220kV Kodasalli breaker at Kadra end got

operated which resulted in tripping of Bus at Kadra

and in turn led to tripping of all elements

06-09-2016

at 14:40 hrs


Kadra power station of

KPCL

58/I/3

(GD)

PendingKPCLKPCL to take steps to replace the existing static

protection relays for Generator Units and Generating

Transformers (GT’s) with suitable Numerical relays at


While de-synchronising of Unit-2, B-phase pole of

GCB did not open and pole descrepancy relay

operated. Hence all 220KV lines CB hand tripped.

69/II/8

Annexure-IV

Page 22 of 48


Tender published on 21.06.2019. Time line for completion of Work is Dec-2020.


Sedam, Shahapur, Shahabad,

Kapanoor, Humnabad and

Halabarga Stations of

KPTCL

01-02-2018

at 17:46 hrs

High resistance fault occurred in 110kV Sedam-

Chittapur line near Sedam end. Line DEF operated and

backup OC protection of 100MVA transformer

operated at Sedam end. But line breaker and

transformer HV breaker didn’t open due to problem in

trip circuit. This resulted in cascade tripping of

upstream feeders and power supply was lost to six

220kV stations of KPTCL.

KPCL to disable GFC protection on all lines

emanating from their generating stations.

KPCL Review Meeting on 21.12.2018

KPCL informed that compliance w.r.t. Implementing the recommendation would be

furnished soon.


'GFC protection will be disabled in all lines in coordination with M/s.KPTCL

KPCL mail dated 10.05.2019 & 25.06.2019:

Letter addressed to CE, RT, KPTCL dated: 10.04.2019 to disable GFC protection

in all 220kV lines . Reply is awaited.


Letter addressed to CE, RT, KPTCL dated: 10.04.2019 to disable GFC protection

in all 220kV lines . Reply is awaited.

Pending


Varahi power station

15-03-2018 at

22:36 hrs

There was Y-phase to ground fault on 220 kV Varahi -

Shimoga line-2. Consequent to persisting fault in ‘Y’

phase, the breaker failure protection operated resulting

in operation of 220KV bus bar protection at Varahi,

tripping all the connected lines and Varahi running

units.

KPCL to take steps to put double-bus operation into

service at their 220 kV Varahi PH.

KPCL Status received vide mail dated 25.07.2018:

Under Implementation.

KPCL mail dated 20.12.2018 & 23.01.2019 & 23.03.2019:

Retrofitting of 220kV Bus Isolators is under progress. Proposed to be in service after

April-2019


4 Set of Isolators of VS1, VS2 & VM2 bay of North Bus were cmpleted. Remaining

bays will be completed after Concurrence of LC from LDC

KPCL mail dated 25.06.2019 & 16.07.2019:


bay will be completed after monsoon season i.e during November -2019

Pending

78/I/1 Complete Outage of 220 kV

Varahi UGPH.

24-08-2018 at

11:00 hrs

Due to suspected mal-operation of 220KV bus bar

protection at Varahi, all the connected lines and Varahi

running Units got tripped. (6 nos 220kV lines and 4

nos Varahi generating station running Units). This

resulted in complete outage of 220kV Varahi UGPH

1. KPCL to take steps to put double-bus operation into

service at their 220 kV Varahi UGPH by December,

2018.

2. KPCL to employ correct operational practices like

keeping DC fuses of B/C CB intact during bus

changeover works, disabling back-up protections of

B/C CB during bus changeover works & enabling

them with proper settings only when it is used as Main-

CB of the grid elements.

KPCL KPCL mail dated 20.12.2018 & 23.01.2019:

1. Retrofitting of 220kV Bus Isolators is under progress. Proposed to be in service

after April-2019 --- Pending

2. ---- Completed.


1) Retrofitting of 220kV Bus Isolators is under progress. Proposed to be in service

after April-2019



bays will be completed after Concurrence of LC from LDC.

KPCL mail dated 25.06.2019 & 16.07.2019:


bay will be completed after monsoon season i.e during November -2019

Pending

06-10-2017 at

22:22 hrs

Tripping of 220 kV Kaiga-

Kadra line-1

PendingKPCLKPCL to take steps to replace the existing static

protection relays for Generator Units and Generating

Transformers (GT’s) with suitable Numerical relays at


While de-synchronising of Unit-2, B-phase pole of

GCB did not open and pole descrepancy relay

operated. Hence all 220KV lines CB hand tripped.

69/II/8

Annexure-IV

Page 23 of 48


1) Preparation of technical specification is completed. Tender will be floated during

3rd week of May- 2019 for control & protection system along with SCADA.

2) English Electric make static type relay is used for NPS protection system at Unit

no.2. The detailed report shall be furnished shortly.


1) Preparation of technical specification is completed. Tender will be floated during

1st week of July 2019 for control & protection system along with SCADA.

2) Existing relays are English Electric Static type

@ GT -2 side, Unit breaker opened at 3MW, HV side current is

0.045A(CTR:200/1A), Since LBB setting I= 0.2A, t=0.2sec, Hence LBB is not

operated.

at the same time,@Generator-2 side ,current is 0.9A(CTR-4000/5A, I2s=7.5% of

secondary current i.e alarm=80% of I2s(i.e 0.3A pickup value), since R pole of

breaker closed condition till manual opening of all 4lines, Due to continous

current(>0.3A), However, NPS operated.


1. Timeline for completion of work July 2020.

2. PCSC confirmed the correctness of NPS relay settings adopted at Kadra. --

Completed.


1) Tender published on 21.06.2019. Time line for completion of Work is Dec-2020.

2) Completed.


1. In view of operating 220kV Ambewadi SS in split bus mode, action is being taken

up by KPTCL. Problem in the 220kV bus coupler breaker is attended and isolator

overhauling work is under progress. Spilt bus operation at Ambewadi will be made

possible at the earliest. --- Pending

2. ICT Protection system at Ambewadi and trippings occured at Supa GS during the

instance is checked up and remedial measures already furnished in this regard.

---- Completed

Mail recieved on 29-07-2015:KPTCL Mail dated 16.12.2017 & Review Meeting dated 19.12.2017:

1. Recommended works at Ambewadi have not been taken up due to various problems

faced due to poor response from the turn key agency M/s ERL. A site meeting is

planned during this month to discuss about further plan of action for attending SRPC

recommendations pertaining to the Sub station.

The issue was discussed in the review meeting. Considering the importance of the

substation and delay in executing the works, it was decided to escalate all pending

issues relating to Ambewadi SS to KPTCL top Management for early completion.

KPTCL mail dated 20.12.2018:Mail received on 28-04-2015:

Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action

is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR

will be enabled.


1. Procurement of Bus bar and LBB protection is in the final tendering stage. KPTCL Mail dated 16.12.2017:

1 & 2) Replacement of Bus Bar Protection is included under R&U project. Awarded

to M/s GE Ltd. Panels have alredy been supplied by the Agency. The work will be

taken up on top priority.


41/I/4 Pending

82/I/3

R-Phase to ground fault occurred on 220kV Sedam-

Shahpur line. Fault not cleared from Sedam end due to

stuck-breaker condition. While the Sedam- Sahapur

line tripped from Shahapur end in Zone-1, the other

220 kv lines from Sedam tripped at remote ends in

Zone-2. This caused complete outage of 220kV Sedam

substation.

GD-1 at 220kV Ambewadi

Station of KPTCL

1) KPCL to ensure that DR and EL for all events are

made available. If Static relays with no DR are present

in Station, standalone Disturbance recorder and Event

logger should be provided.

2) KPCL to investigate the operation of Negative

sequence relay and report to SRPC since the operation

of Negative sequence relay due to stuck breaker

condition is not proper as per protection philisophy

During de-synchronising of Kadra unit#2, R-pole

didn’t open due to struck breaker condition. Pole

Discrepancy operated. All the connected 220kV lines

at Kadra end were hand tripped.

04-02-2019 at

20:19 hrs

Complete Outage of 220kV

Kadra Power House of

KPCL & 220kV Karwar SS

of KPTCL

PendingKPCL

Complete outage at 220kV

Sedam Substation of KPTCL

(GD-1)

KPTCL

22-12-2014

at 21:22 hrs

40/I/1

1. Status? 1. KPTCL to provide Bus bar and LBB

protections for 220 kV bus at Sedam S/s.

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

Sedam-Tandur inter-state line.

27-01-2015 at

8.00 hrs

1. Till the completion of R&M works for bus bar and

LBB protection, KPTCL shall explore the possibility

of having split bus operation at Ambewadi and submit

the details of the same to PCSC forum.

2. KPTCL shall provide the details of the tripping of

Supa hydro station connected downstream from 110

kV bus.

PendingKPTCLTriggering incident was B-phase to earth fault in

220kV Ambewadi- Nagzari line-1. B-pole of breaker

did not open at Ambewadi end. LBB protection not

available at Ambewadi end. All elements tripped on

Zone-2 from remote ends.

Annexure-IV

Page 24 of 48


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

2. A/R yet to be enabled.


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

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

line. AR will be enabled after restoration of PLCC.

KPTCL Mail Recieved dated 22-11-2017:

Bus Bar Protection panel and required Wave traps are supplied under R&U. Wave

trap to be commisioned in Tandoor line and PLCC to be restored.Once PLCC is

restored AR will be enabled.


1. Replacement of Bus Bar Protection is included under R&U project. Awarded to

M/s GE Ltd. Panels have alredy been supplied by the Agency. The work will be taken

up on top priority.

2. AR feature will be enabled during retrofitting of Main-2 relays.


1 & 2) KPTCL informed that the works are under progress and are targeted to be

completed by February, 2018. Review meeting on 27.06.2019:

1. Timeline - September 2019

2. Completed


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

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

line. AR will be enabled after restoration of PLCC.

KPTCL Mail Recieved dated 22-11-2017 & 16.12.2017:

1.Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-

Ponda and Ambewadi-Xeldom lines are radial lines, it was decided that enabling AR


The protection issues pertaining to Ambewadi was appraised to the management

and proposal for construction of new GIS SUb stations has been approved by KPTCL

management. Further as per SRPC directions and in view of attending protection audit

recommendations pertaining to Ambewadi SS without linking with new Station

proposal, action has been taken to include the works in extended scope of R&U

project awarded to M/s GE T&D India Limited. Addition materials required are yet to

be supplied by M/s GE. work expecnted to be completed in 5 months.


1. Since 220kV Ambewadi -Ponda line is radial, this recommendation is dropped.

2. Timeline will be in timated by KPTCL

12-03-2015 at

7:51 hrs

Complete outage of 220kV

Sedam substation of KPTCL

PendingKPTCL1. KPTCL shall provide A/R feature on Ambewadi –

Ponda 220 kV D/C inter-state line.

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

LBB protection, KPTCL shall explore the possibility

of having split bus operation at Ambewadi and submit

the details of the same to PCSC forum.

Fault in 220kV Ambewadi-Nagjheri line-2Complete outage of 220 kV

Ambewadi substation of

KPTCL

42/I/1 PendingKPTCL

42/I/2

(GD)

1. KPTCL to provide Bus Bar protection and LBB

protection at Sedam S/s and furnish the status of their

implementation to PCSC forum.

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

Tandur inter-state line.

Fault occurred in 220kV Sedam-Shahpur line15-02-2015

at 14:24 hrs

Annexure-IV

Page 25 of 48

KPTCL mail received on 23-01-2016:

Will be complied in a months time.


Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-


is not required. To clear the faults in the abovelines early, the timings of the Zone 2

was reduced to 150mS and the Back Up EFR timings have been reducedto 150mS.


Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-


is not required. To clear the faults in the abovelines early, the timings of the Zone 2

was reduced to 150mS and the Back Up EFR timings have been reduced to 150mS.

In view of the above, it is requested to drop the issue from this list.


KPTCL informed that AR would be enabled at Ambewadi end for lines other than

Ponda and Xeldom lines during retrofitting of Back Up protection by Distance

protection relay at Ambewadi.


The protection issues pertaining to Ambewadi was appraised to the management

and proposal for construction of new GIS SUb stations has been approved by KPTCL

management. Further as per SRPC directions and in view of attending protection audit

recommendations pertaining to Ambewadi SS without linking with new Station

proposal, action has been taken to include the works in extended scope of R&U

project awarded to M/s GE T&D India Limited. Addition materials required are yet to

be supplied by M/s GE. work will be completed in 5 months


1. Work order plced. Timeline requested December 2019.

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

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

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

were hand tripped after deenergization of bus at

Ambewadi.

30-09-2015 at

10:41 hrs

Outage of 220kV Ambewadi

station in Karnataka

PendingKPTCL KPTCL to fast-track providing A/R on all 220 kV

lines emanating from Ambewadi SS to prevent Station

shut-down on temporary faults.

48/I/3 Status?

Annexure-IV

Page 26 of 48

KPTCL Mail received dated 25-04-2017:

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

under R&U.


GE Ltd has already supplied the necessary Bus Bar protection panels for replacement

of the existing static type BBP by new numerical BBP with 4 zone protection under

R&U project. The work of commissioning the same will be taken up shortly.


Due to operational constraints two/ multi bus operation is not being implemented.


It was noted that Shimoga SS is having required configuration for providing double-

bus operation. However, due to large no. of feeders (15 in no) with variable gneration

at certain remote ends like Varahi, the flows on these lines are bound to vary. As such

it is necessary to zero in on appropriate arrangement of feeders on different buses so

that bus-isolators of the feeders are not overloaded.

The issue was discussed. KPTCL was asked to try out multi-bus operation on trial

basis to arrive at suitable arrangement of feeders.


Bus sectionaliser breakers have to be provided for operating Shimoga in multi bus

mode. Estimates have to be prepared by CEE,TZ,Hassan. Work expected to be

completed in 1 year.


1. The necessary Bus Bar protection panels are already supplied to Chikkodi under

R&U project. Presently R&U works at sub stations subjected to audit are taken up.

After completion of PAR works, the baove works are planned.

--- Pending

2. --- Pending

3. --- Pending


1.The necessary Bus Bar protection panels are already supplied to Chikkodi under

R&U project. Control cables have to be supplied. Presently R&U works at sub

stations subjected to audit are taken up. After completion of PAR works at 26 Sub

stations, remaining works will be taken up through M/s GE.

--- Pending.

2. --- Pending

3. --- Pending


1. KPTCL informed that BBP would be provided by April, 2018.

---- PendingKPTCL mail dated 20.12.2018:

1). Bus Bar Protection work is included under R&U. work expected to be completed

in 3 months ---- Pending

2). Major equipment failure reports are being sent to CEA regularly ----

Completed.


1. Timeline for completion of work is September 2019

2. Completed

Tripping of 220 kV Chikkodi-

Mudshingi and 220 kV

Chikkodi-Talandage lines

01-07-2016 at

03:03 hrs

Pending52/I/3 Complete outage of 220 kV

Shimoga substation

KPTCLKPTCL to operate 220 kV Shimoga on multi-bus

operation under normal conditions, and put it on single-

bus operation only under emergency conditions.

KPTCL1.KPTCL to take steps to provide busbar protection at

their 220 kV Chikkodi inter-regional substation, and

furnish a time-line for the same.

2.KPTCL to review distance protection settings for

220 kV Chikkodi – Kudachi line.

3.KPTCL to furnish equipment failure report of the

current incident to PSE&TD Division of CEA with a

copy marked to SRPC.

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

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

220KV Chikodi- Belgaum-I line tripped on DEFR

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

Distance protection and also 100MVA transformer-2

tripped on E/F protection.

57/II/1 Pending

220kV Bus Bar protection operated during failure of R

phase CT in DVG-2 line bay.

22-02-2016 at

15:03 hrs

Annexure-IV

Page 27 of 48

KPTCL mail received dated 25.04.2017:

Numerical BBP is being provided under R&M works.


1). The R&M work of 220kV Hoody SS is under progress and expected to be

comleted before the end of August 2019. Providing Bus Bar Protection to 220kV

buses is a part of R&M work at Hoody ----- Pending

62/II/5 Tripping of 220 kV South

Bus and connected elements

(220kV HSR, 220kV

Nagnathpura, 220 kV

Harohalli, 220 kV

Subramanyapura, 220 kV

20-01-2017 at

14:34 hrs

Triggering incident was fault in 66 kV Somanahalli -

Bannerghatta line and fault was cleared by operation of

Back-up OCR at Somanahalli end.

KPTCL to provide numerical Busbar Protection at

their 220 kV Somanahalli SS at the earliest.

KPTCL KPTCL mail received dated 25.04.2017:

Numerical BBP is being provided under R&M works


Tesing & Commissioning of numerical BBP at Somanahalli is under progress. There

was some technical issue wth BBP scheme supplied to Somanahally which is being

Pending

74/I/2 Complete outage of 220 kV

Ambewadi station

02-04-2018 at

13:46hrs

Loss of supply occurred to 220 kV Ambewadi station

due to tripping of 220kV Nagzhari-Ambewadi line-2

(Source) from Nagzhari power station. After bus dead,

Ambewadi-Ponda lines – 1 & 2 were hand-tripped. In

antecedent conditions, 220kV Ambewadi - Nagjheri

ckt-1, 220kV Ambewadi-Narendra Ckt-1 &2 were out

of service.

1). KPTCL to review operation of SPS at NPH for

proper functionality and changed network conditions

(reduction of generation with tripping of evacuating

lines) and put it into service at the earliest.

2). KPTCL to furnish equipment failure report of the

current incident (R-phase CT in Nagjheri – 1 bay at

KPTCL KPTCL mail dated 20.12.2018:

1). To be reviewed. Expected to be completed in 1 month.---- Pending

2), Being followed ----- Pending


1. Nagjheri SPS shall be studied in view of changed system configuration

Pending

74/II15 Multiple Trippings at

400/220kV Guttur station

21-04-2018 at

12:50 hrs

Triggering incident was fault in 220 kV Davanagare -

Shimoga line. Bus bar protection operated at Guttur

resulting in tripping of all the connected elements. 220

kV Guttur was on single bus operation due to CVT

problem in Bus-2.

KPTCL to put double-bus operation at their 220 kV

Guttur substations by attending to Bus-2 CVT

problem.

KPTCL KPTCL mail dated 20.12.2018:

Bus-2 CVT problem is attended. However due to breaker replacement works, 220kV

side operated in single bus mode.


KPTCL informed that double-bus operation at their 220 kV Guttur would be provided

within two months.

Pending

79/III/9 Tripping of 400 kV JSWEL

–Guttur line

29-09-2018

at 11:30 hrs


was not attempted at JSWEL due to DT receive. At

Guttur end auto-reclose could not be validated with

DR/EL.

KPTCL to furnish a detailed report on tripping event

bringing out reasons for DT sending from Guttur end

to JSWEL on 400 kV Guttur - JSWEL line along with


KPTCL Review Meeting on 21.12.2018:

KPTCL was aksed to furnish status of implementation of the recommendation given

at the earliest.


Pending

80/II/7 Tripping of 400 kV JSWEL-

Guttur line

17-10-2018 at

02:04 Hrs

Triggering incident was R-phase to earth fault in line.

At Guttur end there was operation of pole discrepancy

and resulted on tripping of Y & B pole after a duration

of 2 seconds from the occurrence of fault. FIR, DR &

EL of Guttur end were not furnished.

KPTCL to examine the reasons for sending of DT from

Guttur end to JSWEL end, and furnish an action taken

report including remedial measures taken to rectify the

same.

KPTCL Review meeting on 27.06.2019:

report will be submitted by KPTCL

Pending

82/I/4 Complete Outage of 220kV

Ambewadi Station of

KPTCL

06-02-2019 at

14:51hrs

Fault occurred while test charging of 220kV

Ambewadi – Nagjheri Line -2 from Ambewadi end.

Suspected stuck breaker condition at Ambewadi end)

led to clearing of fault by tripping of remote end

breaker in Zone-2. LBB protection is not active at

220kV Ambewadi station.

KPTCL to investigate the reason for non-tripping of

220kV Ambewadi - Nagjheri line-2 on operation of

SOTF and submit a report regarding the same to

SRPC. Also KPTCL to take necessary measures in

order to ensure healthiness of breaker before

testcharging of any line.



Pending

09-01-2017

at 23:06 hrs

KPTCL Pending1. KPTCL to provide Busbar protection at their 220

kV Hoody SS at the earliest.

2. KPTCL to furnish an Equipment Failure Report on

CT failure to CEA with a copy marked to SRPC.

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

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

2. Fault was cleared by backup protection of ICT's

(220kV lines were being radially operated) due to

absence of busbar protection

62/II/3 Tripping of 220 kV Bus 2

and connected elements

(220kV HAL #1 and 2,

400/220 kV ICT- 1, 2 and

220/66 kV ICT-2) at

400/220 kV Hoody

substation of KPTCL (Load

loss : 590 MW)

Annexure-IV

Page 28 of 48


Alipura substation

20-02-2019 at

12:45 hrs

As informed by KPTCL, Suspected delayed clearance

of fault in 220 kV BTPS-Lingapur line from BTPS end

resulted in tripping of lines from Alipura S/s.

1) KPTCL is recommended to furnish detailed report

regarding spurious operation of DEF at Alipur SSand

check the directionality of DEF on all lines.

2) KPTCL is requested to share the revised zone

settings for Distance protection at BTPS end.



Pending

82/II/12 Tripping of 400kV Kaiga-

Guttur line-1&2

07-02-2019

at 11:49 hrs

Line-1 tripped due to insulator flashover. Line-2

tripped due to zone-3 operation at Kaiga and Direct

trip receive at Guttur

KPTCL is recommended to take necessary measures to

ensure that Main-I and Main-II at Guttur end shall be

of different types (make and model) coherent with the

general protection philosophy followed in SR region.


KPTCL informed that the recommendation has been included as part of R & M work.

Timeline will be informed

Pending

84/II/12 Tripping of 400kV DHONI

GUTTUR line- 1

18-04-2019 at

18:59 hr.

Triggering incident was failure of B-ph CB of 400kV

Dhoni-Guttur line at Dhoni end. This resulted in the

operation of LBB of bus-1 and DT was sent to Guttur

end

1. KPTCL to send equipment failure report,

corresponding to the failed CB at Dhoni SS, to CEA.

2. KPTCL to ensure time synchronization at Guttur

end.

KPTCL Yet to be informed Pending


Nelamangala-Mysore line-2

01-05-2019 at 02:29 hr.Line tripped on operation of over voltage stg-2 at

Nelamangala end

KPTCL to ensure time synchronization of DR and

EL with GPS signal at Nelamangala end.



1&3 at Hoody Substation

13-05-2019 at

15:35 hr.

ICT-3 tripped on operation of 59N neutral

displacement relay. ICT-1 tripped on OCR.

KPTCL to inform PCSC forum regarding the changes

implemented in Hoody ICT SPS and to ensure time

synchronization of relays at Hoody SS.


85/I/4 Tripping of 220kV Sedam-RTPS

line-1&2 and 220kV Sedam-

Tandur line

14-06-2019

at 02:00 hrs

Tripped on Directional Earth Fault indications in Main-

2 relay at Tandur end for fault at Raichur end. Sedam

end details not furnished.

1. KPTCL is recommended to enable A/R on all lines

emanating from 220kV Sedam SS.

2.KPTCL is recommended to commission BBP at

220kV Sedam SS immediately.


85/II/5 Tripping of 400/220 kV ICT-3 at

Nelamangala substation19-05-2019

at 16:11 hrs

As per FIR, ICT-3 got tripped on operation of High Set

Over current trip on 400kV side

1. KPTCL is recommended to enable auto-reclosure

on all lines emanating from 400/ 220kv Neelamangala

SS and to ensure time synchronization of relays at

Neelamangala SS.


85/II/11 Tripping of 400kV Hoody-

Yelahanka line-125-05-2019

at 20:41 hrs

Line tripped at Hoody end only and was holding from

Yelahanka.

KPTCL is recommended to check the spurious

operation of SOTF protection at Hoody SS and submit

a report to SRPC regarding the same .


Annexure-IV

Page 29 of 48

85/II/12 Tripping of 400/220 kV ICT-1at

Guttur Substation26-05-2019

at 10:00 hrs

LV side of 400kV/220kV 315MVA ICT#1 Guttur got

tripped due to CB lockout (B phase)because of low

SF6 gas in the CB

1. KPTCL is recommended to submit a report to SRPC

after the CB pressure leakage problem is attended by

OEM.

2.. KPTCL to ensure that during recharging of Circuit

breakers, cylinders with Non-return valve only are

used to prevent sudden pressure drop in Circuit

breakers.


85/II/22 Tripping of 400kV Dhoni-

Munirabad line06-06-2019

at 02:01 hrs

Line got tripped at Dhoni end. From DR Zone-3 start,

PSB and A/r block was observed.

KPTCL is recommended to submit a report regarding

PSB maloperation along-with the RM suggested by

OEM. Proper legends shall be ensured for digital

signals at Doni end.


85/II/27 Tripping of 400/220kV ICT-2 at

Hoody substation16-06-2019

at 19:20 hrs

ICT-2 got tripped on operation of over-flux protection KPTCL is recommended to adopt v/f settings as per

manufacture suggested curve.

v/f setting for alarm: 1.1 time Vnominal; Time delay

10 seconds;

v/f trip setting : v/f is 1.2 time Vnominal;Time delay

60 seconds


85/II/29 Tripping of 400kV Hiriyur-

Nelamangala line-1 and 400kV

Gooty-Nelamangala line

22-06-2019 at

04:06hrs

400kV Hiryur-Nelamangala line-1 : 'Y' phase bushing

of Hiriyur line-1 reactor failed at Nelamangala end

resuting in a R-Y phase fault. Direct trip was sent to

Hiryur.

400kV Gooty-Nelamangalaline : Line tripped at

Nelamangala end only due to mal-operation of Main-2

distance protection relay (THR).

KPTCL is recommended to submit equipment failure

report to CEA regarding the reactor bushing failure

and also to sort out time synchronization issues of

400kV Hiriyur-Nelamangala line.


85/II/30 Tripping of 400/220kV ICT-1&2

at Munirabad substation24-06-2019

at 20:50 hrs

400/220kV ICT-1&2 at Munirabad end got tripped due

to operation of High set of backup earth fault relay

during failure of Y phase CT in 220kV Munirabad-

Kalyani steel feeder at Kalyani steel end

KPTCL is recommended to submit equipment failure

report to CEA regarding the CT and PT failure.


Annexure-IV

Page 30 of 48


1. coordination of KPCL has been requested for enabling AR lines terminated to

Nagajari.

2. AR will be enabled at Ambewadi end for lines other than Ponda and Xeldom lines

during retrofitting of Back Up protection by Distance protection relay at Ambewadi.

KPTCL Mail dadted 16.12.2017 & Review Meeting dated 19.12.2017:

1. KPTCL informed that Coordination of KPCL has been requested for enabling AR

lines terminated to Nagajari.

--- Pending

2. KPTCL informed that AR would be enabled at Ambewadi end for lines other than

Ponda and Xeldom lines during retrofitting of Back Up protection by Distance

protection relay at Ambewadi. -- Pending


2). Readiness from KPTCL for implementing AR is already confirmed to KPCL. KPCL mail dated 23.03.2019:


version Numerical Line protection relays having IEC61850. Prepration of

specification is under progress.


1) Budgetary offer obtained for replacement of existing PZ1000 relays with new

version Numerical Line protection relays having IEC61850. Preparation of estimation

and specification is under progress.

KPCL mail dated 25.05.2019 & 16.07.2019:



NLDC for DPR is awaited. Further, availing administrative approval for issue of NIT

for replacement of existing PZ1000 relays with new version Numerical Line

protection relays having IEC61850 and preparation of estimation and specification is

under progress. Timeline for completion of work is July 2020.

Status informed during Special Meeting held on 03.06.2016:

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

and Maintenance wing to carry out corridor clearance and maintenance as per

schedule to avoid frequent line faults in this corridor. A letter had also been addressed

to Chief Engineer, Bhagalkot zone, to ensure lines in & around Kali complex are

maintained in healthy condition. --- Completed

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

at the earliest. ------ Pending

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

since 23.05.2016 @ 08.06hrs.

--- Completed

KPTCL Mail received dated 28-06-2016:

2. Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC

for verification and approval


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

3. Both the lines are in charged condition.


1) & 3) --- Completed

2). Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC.,

Yet to be discussed and approved by the SRPC forum. --- Pending


Ambewadi Substation of

KPTCL

29.10.2015 at

14:34 hrs

220kV Nagjheri-Ambewadi line-1 tripped at 13:33 hrs

due to B phase to earth fault. Ambewadi was radially

fed from Nagjheri power station through 220kV

Nagjheri-Ambewadi line-2. Tripping of this line

caused 220kV Bus shut down at Ambewadi and

remaining lines and transformers were hand tripped

1. KPCL to provide A/R on all 220 kV lines emanating

from Nagjheri PH.

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

emanating from Ambewadi SS.

KPCL/ KPTCL49/I/3

PendingKPCL/ KPTCL 1. To avoid tripping of transmission lines on transient

faults, KPCL/ KPTCL is recommended to carry out

periodic patrolling of lines, and ensure their proper

maintenance by carrying out jungle/ bushing clearance

and trimming of tree branches within the RoW of

transmission lines as per the SRPC transmission line

patrolling guidelines (available under the menu item

"All Uploads/ Operation/ Miscellaneous/ Transmission

Line Patrolling Protocol / Guidelines for Southern

Region" on SRPC website).

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

for functionality (reduction of generation with tripping

of evacuating lines) and healthiness.

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

into service if more than 200 MW generation from

Kali Complex (with Nagheri Contribution not less than

50 MW) is ensured on sustained basis.

220kV lines from Nagjheri power house started

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

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

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

which resulted in loss of evacuation path to Nagjheri

station resulting in tripping of running Units and

complete outage at Nagjhheri power station. 220kV

Ambewadi station also got de-energized due to tripping

of source feeders i.e. 220kV Narendra-Ambewadi-1&2

and 220kV Nagjheri-Ambewadi-1&2.

22-02-2016 at

12:36 hrs


Nagjheri power station and

220 kV Ambewadi

substation of KPTCL

51/I/3

Pending

Annexure-IV

Page 31 of 48


1) & 3). --- Completed.


yet to be discussed and approved by the SRPC forum --- Pending


2. The SPS proposed by KPTCL was discussed and the PCSC forum suggested

certain changes for suitable incorporation. KPTCL agreed to look into the same and

assured that the modified SPS would be furnished by January, 2018.


2. KPTCL informed that Nagjheri SPS shall be finalised in 1 month.

KPCL mail dated 23.01.2019 & 23.03.2019:

1) .....Completed


3) .....Completed

KPCL mail dated 13.05.2019 & 25.06.2019

1. 3. Completed




2. KPTCL informed that Naghjeri SPS need to be revisited in view of changes in KPCL mail dated 16.07.2019:

1 & 3) Completed.



PendingKPCL/ KPTCL 1. To avoid tripping of transmission lines on transient

faults, KPCL/ KPTCL is recommended to carry out

periodic patrolling of lines, and ensure their proper

maintenance by carrying out jungle/ bushing clearance

and trimming of tree branches within the RoW of

transmission lines as per the SRPC transmission line

patrolling guidelines (available under the menu item

"All Uploads/ Operation/ Miscellaneous/ Transmission

Line Patrolling Protocol / Guidelines for Southern

Region" on SRPC website).

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

for functionality (reduction of generation with tripping

of evacuating lines) and healthiness.





220kV lines from Nagjheri power house started

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

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

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

which resulted in loss of evacuation path to Nagjheri

station resulting in tripping of running Units and

complete outage at Nagjhheri power station. 220kV

Ambewadi station also got de-energized due to tripping

of source feeders i.e. 220kV Narendra-Ambewadi-1&2

and 220kV Nagjheri-Ambewadi-1&2.

22-02-2016 at

12:36 hrs


Nagjheri power station and

220 kV Ambewadi

substation of KPTCL

51/I/3

Annexure-IV

Page 32 of 48

KPCL mail dated 23.01.2019 & 23.03.2019:

1) …Completed.


3) …Completed.

KPCL mail dated 10.05.2019 & 25.06.2019:

1. & 3. Completed




2. KPTCL informed that Naghjeri SPS need to be revisited in view of changes in

system configuration.


1 & 3) Completed.




Ambewadi station of

KPTCL and 220kV Nagjheri

of KPCL

18-03-2016 at

14:40 hrs

Tamil Nadu

Ambewadi Narendra line-2 tripped on fault and 220kV

ambewadi Narendra line-1 tripped due to over-loading.

Running Units at Nagjheri also tripped during the event

due to tripping of evacuating lines

PendingKPCL/ KPTCL KPTCL Mail received dated 28-06-2016:

Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC for

verification and approval


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

and NA-2 ---- Completed

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

3. Both the lines are in charged condition. --- Completed.


2. Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC.,

yet to be discussed and approved by the SRPC forum. --- Pending


1) & 3). --- Completed.


yet to be discussed and approved by the SRPC forum --- Pending


2. The SPS proposed by KPTCL was discussed and the PCSC forum suggested

certain changes for suitable incorporation. KPTCL agreed to look into the same and

assured that the modified SPS would be furnished by January, 2018.


KPTCL informed that Nagjheri SPS shall be finalised in 1 month.

53/I/3 1. KPCL to furnish a report on the reasons for Unit-6

tripping at Nagjheri PH.

2. KPCL/ KPTCL to modify suitably the SPS at

Nagjheri Power House such that it would also factor in

the over loading of Ambewadi-Narendra lines.





Annexure-IV

Page 33 of 48

Mail dated 18.07.2019

2) Tender has been lodged two times. New indent was reaised on 06.07.19. and

tender floating is expected by August 2019. 3) Tender has been

lodged on 15.07.19 and new indent would be raised for the same shortly.

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

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

setting was raised from 410 to 450 volts. After completing the necessary test, the bus

bar protection put in to service on 29.12.2015.

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

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

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

Mail received on 10-11-2016 & 20.12.2016:

Provision of Bus Coupler bay arrangement was included in the Upgradation works

proposed and the same was sanctioned by MoP through PSDF.

Numerical relay allotted and being commissioned.


Numerical BBP relay was commissioned on 02.02.2017

Status received vide mail dated 12.04.2017 & 01.06.2017 & 15-06-2017:

Numerical BBP relay was commissioned on 02.02.2017.

Provision of Bus Coupler bay arrangement was included in the Upgradation works

proposed and the same was sanctioned by MoP through PSDF.


Numerical BBP relay was commissioned on 02.02.2017.

PendingTANTRANSCO

Status?

21-12-2015 at

6:28 hrs


Mywadi station of

TANTRANSCO

TANGEDCO mail dated 15.04.2017:

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

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

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

Numerical based control panels. --- Pending

2.b) Since 230 KV indoor switchyard has no spare space providing dual CT`s is not

fessible. -- Completed

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


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

2. --- Pending

3. --- Pending


2).P & C wing gives clearance to TTPS to procure the Bus bar protection relays and

protection relays and SER / DR system vide

Lr.CE/P&C/SE/D/EEPC4/AEE3/F.TECH/D.27/17 Dated: 05.10.2017. To get

administrative approval budgetary offer has bar protection relay from various

companies ----Pending

3). SRPC vide Lr: SRPC/SE- III/CEA/2017/6450/DT:27.10.2017 gives features of

SER/DR. Budgetary offer will be called for SER / DR having above features. ---

Penidng


2) & 3) The issue was discussed and TANGEDCO was asked to provide time-line for

implementing the recommendations.

Mail dated 29.01.2018:

Procurement work is under progress and will be completed by December 2018.


TANTRANSCO informed that Tender would be floated by January 2019 and

Procurement is expected by APril 2019. Works would be completed by December

2019.


2. Tender issued. Timline- July 2020.

3. Tender has to be issued. Timline- July 2020.

PendingTANGEDCO1. TANGEDCO to replace existing Check-Zone relay

with a new one possessing required performance.

2. TANGEDCO to take steps to provide numerical

busbar protection at their 220 kV Tuticorin TPS.

TANGEDCO may also explore providing dual CT’s

(on either side) for all B/S breaakers at the time of

commissioning of numerical BBP, if there were no

space constraints.

3. TANGEDCO to take steps to provide for standalone

Event Logger (EL) and standalone Disturbance

Recorder (DR) with automatic downloading facility to

a centralized server.

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

of bus-bar protection for Bus Sections -I & II. Running

Units#1, 4 and 5, 230 kV Kayathar, 230kV

Kudankulam, 230kV Sterlite, Station Transformer-1, 2

& 3 got tripped during the incident. Unit – 2 & 3 were

not in service.

25-01-2017 at

22:36 hrs

Tripping of running Units &

230kV feeders at Tuticorin

TPS of TANGEDCO

(Gen Loss: 640 MW)

62/II/7

Busbar protection got operated for a fault in 230kV

Mywadi-Anaikadavu line

TANTRANSCO to examine the feasibility of

providing two main-zone operation for bus bar

protection by exploring various alternatives like

replacing existing bus-coupler CB with a hybrid bus-

coupler CB that comes with inbuilt CT, replacing

existing BBP relay with another suitable relay that

supports two main-zone operation, and implement the

same.

Annexure-IV

Page 34 of 48

Status received vide mail dated 18-09-2017 & 31-20-2017:

Numerical BBP relay was commissioned on 02.02.2017. Provision of CT in Bus

Coupler bay is arranged and zone segregation will be provided.

Status received vid email dated 12-12-2017:

Numerical BBP relay was commissioned on 02.02.2017. Provision of CT in Bus

Coupler bay has been allotted. Zone segregation will be provided after commissioning

of CT.


TANTRANSCO informed that the recommendation would be complied with by

March, 2018.

TANTRANSCO Mail received on 25-01-2018:

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

provided. Timeline: March-2018.


Civil work completed & CT will be commissioned after strengthening Bus .2

conductor jumpers.Awaiting Bus LC Time line before January 2019.


Erection under progress will be completed before 31.01.2019


Buscoupler bay will be commissioned by June 2019


Buscoupler bay configuation in BBP will be completed by June 2019. Bus

segregation will be ensured by 31.12.2019 after attending Isolator status feedback.


Buscoupler bay configuation in BBP will be completed by June 2019. Bus

segregation will be ensured by 31.12.2019 after attending Isolator status feedback.

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

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

insulator of 230kV Southern Bus was replaced and Bus Bar Protection scheme was

restored on 12.05.2016.

Status received vide mails received on 10-11-2016 & 20.12.2016 & 12.04.2017

& 01.06.2017 & 15-06-2017 & 04.08.2017 & 18.09.2017:

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

be provided for all bays for zone segregation.

Status received vide mails received on 31-10-2017 & 12-12-2017:

Numerical Bus bar protection panel allotted and will be commissioned with zone

segregation..


TANTRANSCO informed that Numerical BBP would be commissioned by March,

2018.


Numerical Busbar protection relay commissioned on 14.05.2018


Control & Status of isolator feedeback to be provided by replacement of Drive

Mechanism box.



Mechanism box.



Mechanism box. Timeline requested upto Dec 2018.


1. TANTRANSCO: Estimate sanctioned for replacement of defective isolator status

feedback. Work under progress. Lightning mask work under progress will be

completed within three days.


TANTRANSCO informed that Double bus operation would be provided by March,

PendingTANTRANSCO21-12-2015 at

6:28 hrs


Mywadi station of

TANTRANSCO

Pending55/I/1

(GD)


Gummidipoondi Station of

TANTRANSCO

12-05-2016 at

12:15 hrs

Flashover of Auto Transformer- 2 HV

B-phase Isolator supporting insulator of 230kV

Southern Bus occurred at Gummidipoondi station. At

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

service for pre-commissioning testing of Auto

Transformer-2. All feeders got tripped due to operation

of zone-2 protection from remote ends.

Busbar protection got operated for a fault in 230kV

Mywadi-Anaikadavu line

TANTRANSCO to examine the feasibility of

providing two main-zone operation for bus bar

protection by exploring various alternatives like

replacing existing bus-coupler CB with a hybrid bus-

coupler CB that comes with inbuilt CT, replacing

existing BBP relay with another suitable relay that

supports two main-zone operation, and implement the

same.

TANTRANSCO TANTRANSCO to take steps to provide double-bus

operation at their 230 kV Gummidipoondi SS.

Annexure-IV

Page 35 of 48



time line requested upto June.2019.



time line requested uptoSep.2019

Pending55/I/1

(GD)


Gummidipoondi Station of

TANTRANSCO

12-05-2016 at

12:15 hrs

Flashover of Auto Transformer- 2 HV

B-phase Isolator supporting insulator of 230kV

Southern Bus occurred at Gummidipoondi station. At

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

service for pre-commissioning testing of Auto

Transformer-2. All feeders got tripped due to operation

of zone-2 protection from remote ends.

TANTRANSCO TANTRANSCO to take steps to provide double-bus

operation at their 230 kV Gummidipoondi SS.

Annexure-IV

Page 36 of 48

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

agreed to de-link the implementation of the Item from the scope of Protection Audit

Recommendations (PAR), and pursue it as part of PCSC Recommendations.

Status received vide mails dated 10.01.2017 & 12.04.2017 & 01.06.2017 &15-06-

2017 & 04.08.2017 & 18.09.2017 & 31-10-2017& 12-12-2017:

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

end in a phased manner.


TANTRANSCO informed that the recommended works of providing different make

Relays for Main-I & Main-II are targeted to be completed by September, 2018.


provision of Different make Relays for Main-I & Main-II will be completed by

September, 2018.



end in a phased manner. Timeline: September-2018.




TANTRANSCO MAIL DATED 11-12-2018:

Different make Relays will be provided for Main-I & II relays at Sunguvarchatram TANTRANSCO MAIL DATED 23.01.2019:





end in a phased manner. Timeline: September-2019

14-09-2016 at

11:13Hrs

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

operated at Alamathy Station during fault in 230 kV

Alamathy-Korattur feeder.

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

Sunguvarchathiram Substation [Carry-Over from Protection Audit Recommendations]

TANTRANSCO Mail received on 10-11-2016 & 20.12.2016:

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

circuits.

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

Status received vide mails dated 10.01.2017 & 12.04.2017 & 01.06.2017 & 15-06-

2017:

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

circuits. AREVA make CTs in Alamathy SS are having different kneepoint voltage

for the cores. CT cores of higher knee point voltage has been choosen for BBP in

230kV Korattur, 230kV OPG-1 & 230kV OPG-2 feeders on 29.11.2016. ----

Completed.

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

Status received vide mails dated 04.08.2017 & 18.09.2017 & 31-10-2017 & 12-

12-2017.

1. ---- Completed

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


2) TANTRANSCO informed that Numerical BBP would be provided by April, 2018

--- Pending

TANTRANSCO mail received on 25-01-2018:

1. --- Complied.

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

2018.

TANTRANSCO MAIL DATED 22.05.2018 & 08.06.2018 & 23.07.2018:

2.Numerical BBP relay will be provided. Timeline: Sep-2018.


1. Complied


Pending1. TANTRANSCO to check the healthiness of BBP

relay by conducting stability test, and take appropriate

remedial action like increasing voltage settings,

ensuring the healthiness of CT’s, using CT’s with

similar characteristics (equal saturation effects &

equal winding resistances) etc. at their 230 kV

Alamathy SS.

2. TANTRANSCO to replace the existing high-

impedance BBP relay with its low-impedance/

numerical variant so as to accommodate variation in

CT characteristics at their 230 kV Alamathy SS.


Alamathy Station

TANTRANSCO Pending

Annexure-IV

Page 37 of 48

TANTRANSCO MAIL DATED 11-12-2018:

Numerical BBP relay to procured. Timeline: Sep-2019.


Numerical BBP relay to be procured. Timeline: Sep-2019.


Numerical BBP relay to be procured. Timeline: Sep-2019.


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

operated at Alamathy Station during fault in 230 kV

Alamathy-OPG-1 feeder.

TANTRANSCO Mail received on 10-11-2016 & 20.12.2016:

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

circuits.

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

Status received vide mails dated 10.01.2017 & 12.04.2017 & 01.06.2017 & 15-06-

2017:

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

circuits. AREVA make CTs in Alamathy SS are having different kneepoint voltage

for the cores. CT cores of higher knee point voltage has been choosen for BBP in

230kV Korattur, 230kV OPG-1 & 230kV OPG-2 feeders on 29.11.2016. ----

Completed.

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

Status received vide mails dated 04.08.2017 & 18.09.2017 & 31-10-2017 & 12-

12-2017.

1. ---- Completed

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


2) TANTRANSCO informed that Numerical BBP would be provided by April, 2018

--- Pending


1. --- Complied.

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

2018.




1. Complied


Pending

15-09-2016 at

22:14 hrs

1. TANTRANSCO to check the healthiness of BBP

relay by conducting stability test, and take appropriate

remedial action like increasing voltage settings,

ensuring the healthiness of CT’s, using CT’s with

similar characteristics (equal saturation effects &

equal winding resistances) etc. at their 230 kV

Alamathy SS.

2. TANTRANSCO to replace the existing high-

impedance BBP relay with its low-impedance/

numerical variant so as to accommodate variation in

CT characteristics at their 230 kV Alamathy SS.


Alamathy Station

Annexure-IV

Page 38 of 48

64/1/4 Complete outage of North

Chennai TPS STG-1

26-03-2017

at 23:14hrs

Tripping of evacuating lines due to fault led to tripping

of running Unit at NCTPS Stg-1

1. TANTRANSCO to take steps to complete insulator

replacement works on the 230 kV lines owned by them

in NCTPS area within 6 months.

2. TANTRANSCO to take steps to implement A/R on

all 230 kV lines emanating from NCTPS-I at the

earliest.

TANTRANSCO Status received vide mails dated 04.08.2017 & 18.09.2017 & 31-10-2017:

1. All the Porcelain insulators were replaced with Polymer insulators in 230kV

NCTPS-I - Tondiarpet feeders - 1 & 2.

---- Completed

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


1. Completed

2. The scheme needs modification to enable AR, since AR was not envisaged for this

station during commissioning. AR will be implemented on all 230kV lines emanating

from NCTPS-I within six months. --- Pending


2) TANTRANSCO informed that A/R would be implemented on all 230 kV lines

emanating from NCTPS-I by June, 2018.


1. Complied.



from NCTPS-I within six months. Timeline:June-2018.

Pending




from NCTPS-I Timeline:Sep -2018.


1. Complied.

2. The scheme needs modification to enable AR, since AR was not envisaged for this TANTRANSCO MAIL DATED 11-12-2018:

2. Enabling AR pending for 3 feeders. ( Sriperumpudhur end breaker problem,

Tondiarpet & Alamathy feeder . static relay to be replaced. Timeline - 1 year


Enabling AR pending for 3 feeders. ( Sriperumpudhur end breaker problem,

Tondiarpet & Alamathy feeder . static relay to be replaced. Timeline -Sep 2019


Enabling AR pending for 3 feeders. ( Sriperumpudhur end breaker problem,

Tondiarpet & Alamathy feeder . static relay to be replaced. Timeline -Sep 2019

77/II/9 Multiple trippings at

400 kV Manali Substation

TANTRANSCO to refer the issue of selective tripping

of 400 kV side breakers, and non-tripping of 230 kV

side breakers due to operation of Densimeters on low

pressure in the instant case to their OEM, and share

OEM’s advice/ remedy in this regard.


OEM will be referred


TANTRANSCO was asked to update the status.

TANTRANSCO MAIL DATED 23.01.2019, 19.03.2019 & 13.06.2019:

The issue was referred with OEM & reply awaited.


OEM reply shall be communicated by end of July 2019


The issue was referred with OEM & reply awaited

Pending

Annexure-IV

Page 39 of 48


Thiruvalam Substation

05-10-2018 at

14:32 hrs

Bus-1 got tripped at 230 kV Thiruvalam substation due

to spurious LBB relay (independent) operation of

230kV Thiruvalam Chittoor line. 230kV Thiruvalam

substation was under single bus operation; hence

operation of LBB protection resulted in tripping of all

connected elements resulting in the complete outage

TANTRANSCO to take steps to implement multi-bus,

multi-zone operation (Double-bus operation) at their

230 kV Thiruvalam SS by December, 2018.

TANTRANSCO TANTRANSCO MAIL DATED 11-12-2018:

Due to space constraint, the equipments could not be erected.


It was noted that the station was on a single (Main) bus and there was not even

transfer bus. In view of the importance of 230 kV Thiruvalam SS, TANTRANSCO

was asked to take steps to provide dobule-bus operation at their 230 kV Tiruvalam

SS.


Feasibility for providing hybrid breaker / shifting of bays will be studied & action

will be taken. Time upto Sep 2019


Bus segregation will be ensured by providing bus coupler bay by extending the


Pending

80/II/12 Tripping of all elements

connected to 230 kV

Anaikadavu SS

06-11-2018 at

21:35 Hrs

Triggering incident was failure of R-ph PT of 230 kV

Anaikadavu Bus-1. 230 kV Bus bar protection of bus-

1 operated resulting in tripping of all the connected

elements. 230 kV Anaikadavu was on single bus

operation due to failure of Bus-2 PT during antecedent

conditions.

1) TANTRANSCO to adopt recommended OVR,

Stage-I and OVR, Stage-II protections at their 400 kV

Anaikadavu and 400 kV Rasipalayam stations, and to

ensure that OVR-I_START signal is configured for

triggering corresponding Event Logger (EL), and OVR-

I_TRIP is configured for triggering corresponding

Event Logger (EL) and Disturbance Recorder (DR).

2) TANTRANSCO to take steps to restore multi-bus,

multi-zone operation at their 230 kV Anaikadavu SS at

the earliest.

TANTRANSCO TANTRANSCO MAIL DATED 23.01.2019 & 19.03.2019:

1……Complied

2.Bus PT is to be supplied by the Turnkey contractor will be replaced by 31.03.2019


Bus PT is to be supplied by the Turnkey contractor


Timeline requested upto December 2019.


Bus PT is to be supplied by the Turnkey contracto

Pending


Sriperumbudur station

28-01-2019

at 01:15 Hrs

Failure of ‘R-phase’ HV side Current transformer (CT)

of 315MVA 400/230kV ICT-3 at 400kV

Sriperumbudur substation (400kV TANTRANSCO

switchyard).

1) TANTRANSCO to ensure proper legends for DR

Digital signals and all required events(including CB

status, Type of protection operated) are captured in

Event logger.

2) TANTRANSCO to extend BBP trip from BusBar

relay to 86A (with source-1 DC) in addition to 86B

(with source-2 DC), or to provide Common trip relay

96 with redundant DC supply.

3) TANTRANSCO to inform the action plan with

timelines for providing Numerical BBP at

Sriperumbdur SS .

4) TANTRANSCO to check the healthiness of all

CT’s in the stationand submit a report regarding the

same to SRPC to prevent any such occurrence in

future.

TANTRANSCO TANTRANSCO MAIL DATED 13.06.2019:

1. At present Duobias relay avaiable I/O configuration could not be carried out.after

changing the relay Digital signals will be configured

2.COMPLIED

3.Provision of Numerical BBP relay covered under R&M work. Tender under

progress.

4.out of 30 CTs, 21 No CTs have been replaced with new one.


1. , 3. Timeline requested upto July 2020.

2. Complied

4. Timeline requested upto September 2019.


1. At present Duobias relay avaiable I/O configuration could not be carried out.after

changing the relay Digital signals will be configured

2.COMPLIED

3.Provision of Numerical BBP relay covered under R&M work. Tender under

progress.

4.out of 30 CTs, 21 No CTs have been replaced with new one.

Pending

83/I/7 Complete outage of

230kV/110kV KR Thoppur

Substation of

TANTRANSCO

11-04-2019

at 13:16Hrs

Triggering incident was failure of Y-ph CT of Bus

Coupler at 230kV KR Thoppur(Salem) SS. Bus bar

protection of Bus-1 and Bus-2 operated resulting in the

tripping of all the connected elements at 230kV KR

Thoppur SS. 400kV/230kV ICT#1 and 2 at Salem also

got tripped during this event.

1.TANTRANSCO informed that replacement of

mechanical relay by Numerical relay is under progress

and it is recommended to submit the action plan

regarding the same with proper time-lines.

2.TANTRANSCO is also recommended to send

equipment failure report to CEA regarding failure of

Bus coupler CT.


1. Replacement of numerical relay under progress

2.Equipment failure report will be sent

Pending

Annexure-IV

Page 40 of 48

83/II/13 230kV Bus dead at 230/110

kV Pugalur

14-03-2019 at

13:24 hrs

Triggering incident was R-phase breaker failure in

230kV Pugalur end of Budansandhai feeder. LBB

operated resulting in tripping of all connected elements.

As reported, 230kV side was on single bus operation

since bus sectionalizer provision is not there. 110kV

side connected feeders did not trip.

TANTRANSCO is recommended to furnish

equipment failure report to CEA regarding failure of

CB.


Equipment failure report will be sent

Pending

85/II/1 Tripping of 400/230kV

MANALI ICT-3

13-05-2019 at

2:42 hrs

ICT-3 got tripped on the activation of HV REF

protection. During test charging of 110 kV Manali-

ETPS -1 , the 110 kV ETPS -1 got tripped on the

activation of Back up relay and Distance relay failed to

act

1. TANTRANCO is recommended to sort out the

malfunctioning of ICT Ref protection in consultation

with OEM and submit a detailed report regarding the

same in 1 month time.

2. TANTRANSCO is recommended to ensure proper

labelling of all digital signals in Disturbance recorders

of lines and ICTs at Manali SS.

TANTRANSCO Yet to be informed Pending

85/III/6 400 KV Thiruvelam – Palavadi

line-1

28-05-2019 at 18:04

hrs

B-phase to earth fault. A/r attempt could not be validated. TANTRANSCO is recommended to check sending of DT from

Palvadi end during 3-ph trip at Palvadi. The time

synchronization issues between Thiruvalem and Palvadi shall

also be rectified.


85/IV/6 Tripping of 400kV Kayathar-

Kanarpatty line-1 & 2

10-06-2019 at 12:22

hrs

Line-1 & 2 tripped at Kanarpatty end due to spurious DT sent

from kayathar end. Feeder did not trip at Kayathar end

TANTRANSCO is recommended to submit a report regarding

the problem with PLCC panel at Kayathar along-with

Remedial Measures suggested by OEM.


Annexure-IV

Page 41 of 48

KSEB Mail received vide dated 17.01.2017:

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

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

Completed

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

not practical for the time being. 48 V DC redundancy was already there. ----

Pending

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

to be completed by the end of 2017. SCADA system of 220kV side will be taken up

Status received vide mail dated 12-12-2017:

1. Detailed engineering of the scheme has been completed. Material procurement is in

progress. ---Pending

2.,3. ---- Completed

4. The SOE and DR are available with time stamping from the numerical relays.

Hence stand alone event logger is not necessary ----- Completed

Status received vide mail dated 11-12-2018:

Work has been already tendered. It is expected that purchase process will completed


Sanction to issue purchase order in progress. Time Frame is January 2020 .

Review meeting on 27.06.2019.

1. BBP will be commissioned by December 2019.

2.,3.,4. Completed

79/I/1 Complete Outage of 220 kV

Idukki Power Station

01-10-2018 at

04:16 hrs

Triggering incident was R-Ph fault in 220kV Idukki-

Kalamassery line-2. R-phase pole of breaker didn’t

open at Idukki end. LBB of Bus-2 operated resulting in

tripping of all connected elements along with running

Unit#4 at Idukki and 50MVA station transformer. At

the same time, 220kV Idukki Kalamassery line-1 also

got tripped at Idukki end. Subsequently running Units 1

and 2 also tripped on Governor oil Low Pressure due to

loss of AC supply. This resulted in complete outage of

1). KSEBL to check & correct the LBB time setting

employed at their Idukki PH to 200 msec.

2). KSEBL o ensure that DR’s & EL’s of all

Protection Relays (PR’s) at their Idukki PH are

configured for recording all mandated protections &

signals.

KSEBL Status received vide mail dated 11-12-2018:

1) Present setting is 180ms.OEM(ABB) suggests that it will give around 200ms

delay as it is having inherent delay is of around 20ms(ie, 180ms +20ms

=200ms).With this setting the fault clearence is found after 220ms.So further revision

may be carried out after discussion.

2)Breaker status will be ready only after completing the GOOSE network as part of

renovation of all feeder panels and Idukki first stage units by June 2019 .

Pending

80/II/5 Multiple trippings at 220 kV

Madakathra station

15-10-2018 at

08:57 Hrs

Triggering incident was Y-phase to ground fault in

220kV Madakathra – Palakkad_KL (Ellapully) line

due to flashover of pilot insulator string. Auto-reclose

was successful at Madakathra end. At the same time

bus differential relay Zone-C mal-operated resulting in

tripping of all elements connected to the bus.

KSEBL to take steps to replace the existing static

(high impedance type) 220 kV BBP with numerical

Busbar protection at their 220 kV Madakathara SS.

KSEBL Status received vide mail dated 11-12-2018:

In progress


Status as on 18.03.2019: Estimate sanctioned by CE(Transmission North ) and have

prepared the technical specifications.Tendering procedures are yet to get started.


Pending

23-08-2016

at 11:20 hrs


Kalamassery Substation

Triggering incident was conductor snapping in 110 kV

Kalamassery- Kaloor feeder

1. Time-frame?58/I/1

(GD)

KSEB to take steps to provide the following at their

220/ 110 kV Kalamassery SS:

1. Busbar protection at 110 kV level

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

common earthmat

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

and communication (48 V) applications

4. Stand-alone Event Logger

KSEB Pending

Kerala

PED

Annexure-IV

Page 42 of 48

82/I/5 Complete Outage of 220kV

Bhramapuram substation of

KSEB

08-02-2019 at

10:28 hrs

Complete outage of 220kV Brahmapuram SS occurred

due to suspected mal operation of Bus Bar protection.

1) KSEBL to furnish detailed report regarding the

healthiness of BBP operation at 220kV Brahmapuram

after testing of the same on 12th April 2019.

2) KSEBL to submit the action plan regarding

(i) Replacing of the Static High impedance BBP

(using CRM relays) with Numerical BBP.

(ii) Replacement of CRM relays and relays with no

Disturbance recording facilitites.

KSEBL Status received vide mail dated 03.05.2019:

1) Detailed report sent on 02.05.2019…..Completed.

2) As reported earlier in this regard, the permanent solution to this problem is to

replace the existing high impedance static relay with a low impedance numerical

relay. The station authorities have already initiated action to implement the same by

June 2020.

Pending


Edamon SS of KSEB

27-05-2019 at

12:30 hr.

Triggering incident was three phase to earth fault in

220 kV Edamon Bus 1 and 2. Bus 1 and 2 Bus bar

protection operated resulting in the tripping of all

connected elements.

1.KSEBL may develop proper operational code for

procedures to be followed while performing operations

in switchyard and sensitize their operators to reduce

operational errors. 2.ksEBL to ensure time

synchronization of relays at 220 kV Edamon SS.

KSEBL KSEBL mail dated 30.07.2019:

1. proper operrational code is avilalable in 220kV SS Edamon

2. All 220KV relays of Edamon substation are synchronized with GPS clock . Out of

this, 3 relays are having hardware issues with time synchronisation switch . This

problem will be resolved by August 2019 itself.

Pending


Pothenkode Substation of

KSEB

04-07-2019

at 01:18 hrs

Triggering incident was failure of suspension insulator

of 220kV Pothenkode – Trivendrum ckt-2. Bus bar

protection of Bus-1 and Bus -2 operated resulting in

tripping of all connected elements.

1. KSEBL is recommended to investigate the non-

operation of zone selective Busbar Operation at 220/

110kV Pothencode SS and submit detailed report

regarding reasons for the same alongwith remedial

measures taken.

2. KSEBL is recommended to ensure time

synchronization of relays at 220/ 110kV Pothencode

SS.

KSEBL Yet to informed Pending

85/II/9 Tripping of 220KV Sabarigiri-

Theni line23-05-2019

at 16:12 hrs

Line tripped on operation of DEF at Theni end KSEBL is recommended to configure in DR and EL

the pick up and operation of relevant distance

protection zones in the event of distance protection

operation.

KSEBL Yet to informed Pending


1 at Khammam

27-01-2019

at 14:33hrs

ICT-1 at Khammam tripped on operation of IV side

non directional Over-current high set during failure of

L.A in 220kV Khammam (Budhidampadu)-Suryapet

line-2

PGCIL (SR-I) to immediately take necessary actions

to raise the Highset pick up current setting as per

protection standards since unwarranted tripping of ICT

for fault on 220kV line compromises the reliability of

Power system. In any case the transformer protection

should not encroach into protection zone of nearby

protection element.

PGCIL (SR-I) Review meeting on 27.06.2019:

PGCIL (SR-I) informed that the ICT high set settings have been sent by mail

Pending

84/II/3 Tripping of 400kV KTPS-

Khammam line

11-04-2019 at 13:59 hr.Line tripped on operation of overvoltage stage-1

protection at KTPS end and DT received at Khammam

end. Phase voltages at KTPS end could not be verified

from the DR furnished.

PGCIL (SR-I) to ensure time synchronization of DR

and EL at Khammam end.

PGCIl (SR-I) Yet to be informed Pending


2 at Bangalore (Somanahalli)

26-10-2018 at

12:10 Hrs

400/220 kV ICT-2 at Bengaluru (Sonamahalli) tripped

due to operation of LV side over flux protection which

in turn was due to suspected 220 kV CVT problem.

PGCIL (SR-II) to configure DR’s & EL’s all

protection relays at their 400/ 220 kV Somanahally SS

for all mandated protections and signals.

PGCIL (SR-II) Review meetinmg on 27.06.2019:

PGCIL (SR-II) was asked to furnish the status of implementation of the

recommendation at the earliest.

Pending

84/II/2 Tripping of 400kV

Somanahalli-Dharmapuri

line-2

07-04-2019 at

18:02 hr.

Line tripped on operation of over voltage stage-1

protection at Somanahalli. Somanahalli end DR: Vr-

240kV, Vy-253kV, Vb-241kV. Y-phase voltage was

higher than R and B phase

1. PGCIL (SR-II) to configure OVR start and OVR

trip signal in Event logger to facilitate verification of

adopted OVR grading.

2.PGCIL (SR-II) to ensure time synchronization of

DR and EL at Somanahalli end and Dharmapuri end.

PGCIL (SR-II) Yet to be informed Pending

84/II/15 Tripping of 400kV Bus-1

and connected elements at

400kV Bidadi substation

25-04-2019 at 08:01 hr.Triggering incident was failure of R-ph CB of bus

reactor at 400kV Bidadi. Bus bar protection of Bus-1

operated resulting in the tripping of all elements

connected to Bus-1

1. PGCIL (SR-II) was requested to send the

equipment failure report to CEA.

2.PGCIL (SR-II) is recommended to share the

feedback of OEM regarding decomposition of SF6 gas.


PGCIL (SR-I) & PGCIL (SR-II)

Annexure-IV

Page 43 of 48

85/II/8 Tripping of 765/400kV ICT-

1 and 2 at Kurnool

substation

21-05-2019 at

18:11 hrs

ICT 1 and 2 got tripped due to maloperation of

Bucholz relays during the charging of 400KV Kurnool-

Nanoor line 1 which tripped on SOTF

PGCIL (SR-I) is recommended to submit a detailed

report regarding operation of Buchholz relay of 765/

400kV ICT 1& 2 during through fault after

consultation with OEM along-with the remedial

measures taken to prevent occurrence of any such

incidence in future.

PGCIL (SR-I) Yet to be informed Pending

85/II/16 Tripping of 400kV Tumkur-

Bidadi line-1&2, 400kV

Tumkur-Cuddapah line-2,

400kV Tumkur-Pavagada

line-2

29-05-2019 at

6:11 hrs

Lines tripped due to Y-N & Y-B phase to earth fault PGCIL (SR-2) is recommended to submit Equipment

failure report to CEA regarding the failed LA.


85/II/18 Tripping of 765/400kV ICT-

2 at Kurnool

02-06-2019 at

17:41 hrs

ICT-2 got tripped on operation of Back up directional

over current due to through fault (Y-B phase fault).

PGCIL (SR-1) is requested to check the operation of

ICT HV side High set O/C protection for through fault

and submit a report regarding the same.

PGCIL (SR-I) Yet to be informed Pending

85/III/7 Tripping of 400kV Pugalur-

Karaikudi line-1

31-05-2019 at

17:44 hrs


was successful at Karaikudi, At Pugalur end there was

3-phase trip

PGCIL (SR-2) is recommended to ensure proper

condition monitoring of their CB’s such as sufficient

air pressure.


Others

Annexure-IV

Page 44 of 48


TPCIL station

25-10-2017 at

19:33 hrs

400 kV TPCIL-Nellore PS line-1 got tripped from

TPCIL end during fault in 400kV Nellore-Nellore PS

line-2. Running units at TPCIL got tripped due to loss

of evacuating line. 400kV Nellore PG - Nellore PS line-

2 and 400kV TPCIL - Nellore PS line-1 were under

shutdown.

TPCIL to configure DEF protection such that it

remains in blocked condition as long as Distance

Protection is active, and becomes active only when

distance protection does not pickup.

TPCIL Review Meeting on 21.12.2018:

It was noted that no TPCIL representatives had come to attend the meeting

Review meetinmg on 27.06.2019:

No representative from the utility attended meeting and it is requested to submit status

regrading the recommendation at athe earliest.

Pending

Status revided vide MAPS mail dated 06.12.2016;

1. The settings given by M/s TANTRANSCO were adopted for Main –I & Main- II

relays for both the lines. The same settings were verified to be same. Subsequently

calibrated was done and no drift was observed. --- Completed

2. From May 2016 onwards, the DR, EL and trip report are being sent by mail to

SRLDC, Bengaluru by MAPS. --- Completed

B-phase CT failure occurred in 230 kV S.P.Koil -

MAPS line-1. Busbar protection got operated at

SP.Koil station. All elements except 230kV Oragadam

and 230kV Kalivandapattu got tripped at 230kV

S.P.Koil station. ‘Y’ phase CT and support insulators

also got damaged.

1.MAPS to furnish a detailed report on the tripping of

SP Koil – MAPS lines 1 & 2 at MAPS end with focus

on the correctness of the settings of Main-I & Main-II

relays (for primary & back-up protections) on both the

lines.

2.MAPS to take steps to provide down-loading facility

02-04-2016 at

17:08 hrs


S.P.Koil Station of

TANTRANSCO

PendingNPCIL (MAPS)

Annexure-IV

Page 45 of 48

78/II/2 Tripping of 400 kV Neyveli

TS2Exp -Pugalur line

01-08-2018

at 11:56 hrs

Triggering incident was failure of R-ph tension

insulator string/ flashover in 400 kV Bus-1 at NLC

TS2Exp end. Busbar protection had operated resulting

in tripping of all main breakers connected to 400kV

Bus-1 at Neyveli TS2 Exp. In 400kV NLC TS2Exp -

Pugalur line, fault was sensed in Zone-1, R-N at

Pugalur end resulting in a single phase trip. Direct Trip

was received at Pugalur end due to operation of over

voltage Stg-2 at NLC TS2Exp.

1. NLCIL to furnish a report along with a suitable

SLD on the tripping event explaining the observed

discrepancies [DPR, Z1 operation, instantaneous

operation of OVR-II operation], and remedial action

taken to attend the same.

2. NLCIL to configure DR’s & EL’s of all protection

relays at their NLC TS-IIExp station for all mandated

protections & signals.

NLCIL Review Meeting on 21.12.2018:

NLCIL was asked to furnish the status of implementation of the recommendation

given at the earliest.




Pending

79/II/8 Tripping of 400 kV NLC TS-

2 (Exp) – Pugalur line

10-09-2018 at

20:57 hrs

Line tripped on B-N fault. Auto-reclose was not

attempted at Pugalur end due to DT receipt from NLC

TS2Exp end. At NLC TS2Exp end, V>2 trip was

observed in DR. Analog voltages recorded in DR were

observed to be less than that required for O/V Stage-II

operation.

NLCIL to furnish a detailed report on tripping event

explaining the observed discrepancies , and proper

reasons for tripping of the line considering both the

Main-relays including remedial action taken w.r.t.

healthiness/ replacement of Main protection relays on

400 kV NLC TS2Exp–Pugalur line.

NLCIL Review Meeting on 21.12.2018:

NLCIL was asked to furnish the status of implementation of the recommendation

given at the earliest.


it is requested to submit status regrading the recommendation at athe earliest.

Pending


PS – SGPL line-1

14-11-2018 at

20:20 hrs

Y- ph to earth fault occurred in line due to snapping of

GIS to Air bushing conductor at SGPL switchyard.

The conductor got grounded such that the fault was

being fed by NPS bus and there was earth fault and

broken conductor start at SGPL end. NPS end got

tripped in Zone-2 due to non-receipt of carrier resulting

in a 3-ph trip at NPS. After 500ms, earth fault

occurred at SGPL end resulting in Zone-1 operation

and 3 phase trip. A/R was not attempted at SGPL end

SGPL to examine the reasons for no-operation / failure

of Auto-reclosure from their end for the subject

tripping, and furnish an action taken report detailing

remedial measures taken to PCSC forum.

SGPL Review meetinmg on 27.06.2019:



Pending

80/III/6 Tripping of 400 kV Neyvelli

TS2 (Exp) - Pugalur line

07-11-2018 at

05:50 Hrs

400 kV Neyvelli TS2Exp - Pugalur tripped on

B-phase to ground fault due to DPR, Z1 operation.

Auto-reclose was successful at Pugalur end and the

line tripped at Neyveli TS2Exp end only. Auto-reclose

was not attempted at Neyveli TS-2(Exp) end

NLCIL to furnish a detailed report on the reasons for

A/R non-operation for the subject tripping at their

NLCTS2Exp station including remedial measures

taken to PCSC forum.

NLCIL Review meetinmg on 27.06.2019:



Pending


Kayamkulam –Punnapura-2

24-02-2019 at

03:05hrs

Line tripped on B-phase to earth fault. Auto-reclose

was successful at Punnapura. A/r was not attempted at

Kayamkulam and there was pole discrepancy operation

resulting in tripping of R and Y pole of CB.

It was noted that no representative of NTPC attended

the meeting.

NTPC (Kayamkulam) to furnish detailed report

regarding failure of Auto-reclosure at Kayamkulam

end for Kayamkulam –Punnapura line-2.

NTPC (KYKLM) Review meeting on 27.06.2019:




Trip report for Tripping of 220 kV Kayamkulam –Punnapura-2 submitted , but for

submitting detailed report for Auto-reclosure at Kayamkulam end not operating for

Kayamkulam –Punnapura line-2 , half day shutdown of Kayamkulam –Punnapura

line is required to check reason for failure . May please approve half day outage of

Kayamkulam –Punnapura line and intimate us atleast one day in advance.

Pending


Kayamkulam –Punnapura-2

05-03-2019 at

00:30hrs

220kV Kayamkulam-Punnapura -2 tripped on Zone-1

distance protection due to R-N fault. Auto reclose

operated and successful at Punnapara end but didnot

operate at Kayamkulam end.

It was noted that no representative of NTPC attended

the meeting.

NTPC (Kayamkulam) to furnish detailed report

regarding failure of Auto-reclosure at Kayamkulam

end for Kayamkulam –Punnapura line-2.

NTPC (KYKLM) Review meeting on 27.06.2019:




Trip report for Tripping of 220 kV Kayamkulam –Punnapura-2 submitted , but for

submitting detailed report for Auto-reclosure at Kayamkulam end not operating for

Kayamkulam –Punnapura line-2 , half day shutdown of Kayamkulam –Punnapura

line is required to check reason for failure . May please approve half day outage of

Kayamkulam –Punnapura line and intimate us atleast one day in advance.

Pending

Annexure-IV

Page 46 of 48


NLC1

Expansion(NLC1EXP)

05-06-2019at 18:51 hr.Triggering incident was failure of Y-phase CT of GT-1 (Generator Transformer) at 400kV NLC1EXP. Bus-1 Bus bar protection operated resulting in the tripping of NLC1EXP U#1 and 400kV NLC1EXP- Nagapattinam line 1. NLCIL to check the healthiness of R & B ph CT of

Unit-1 at NLC TS1(Exp) and if found unhealthy

replace the same alongwith replacement of Y-ph CT.

CT replacement plan and timeframe shall be informed

to SRPC.

2.NLCIL in coordination with PGCIL(SR-II) to

resolve the time syncronisation issues in 230kV NLC

TS1(Exp) – Nagapattinam line.

3. NLCIL was also requested to investigate the reason

of unwarranted DT sent to NLC TS1 (Exp) end from

NLC TS2 end and resolve the same.

NLCIL NLCIL mail dated 09.07.2019:

AT TS2 Side Siemens 7SA52 & Micromho relay are used for distance protection.

During the incident Micromho has sensed the CT blast as a Zone-1 fault and tripped

the feeder. Adt signal was send to TS1 Exp end. The relay will be tested during the

next shut down.

Pending


Dichipally–Ramagundam

line

20-04-2019 at

18:09 hr.

Y phase to Earth fault in the line. Line did not auto-

reclose at Ramagundam end

1. It was noted that no representative of NTPC

(Ramagundam) attended the meeting.

2. NTPC (Ramagundam) to submit a detailed report

regarding non-operation of A/R at Ramagundam end

and Remedial measures taken for the same

NTPC (RMGDM) Yet to be informed Pending

84/II/20 Tripping of 400kV Neyveli

TS2- Neyveli TS-I (EXP)

and 400/230 kV ICT-1

atNeyvli

07-05-2019 at 20:56 hr.400kV/230kV ICT-1 got tripped on Differential

protection due to failure of R phase bushing on the HV

side. For 400kV Neyveli TS2- Neyveli TS-I (EXP), R

pole breaker at TS1Expgot tripped. TS2 End breaker

tripped on trip command received from TS1 EXP

1. NLCIL to measure the earth resistance of Neyveli

TS-2 SS and submit the same to PCSC forum. NLCIL

to check the healthiness of LAs of ICTs and confirm

proper earthing.

2.It is also recommended to furnish a report on

adequacy of ground wire shielding of switchyard.

3. NLCIL to ensure Time synchronization of relays at

Neyveli TS-2 SS.

NLCIL NLCIL mail dated 09.07.2019:

1) The earth pit resistance of the ICT1 LA was measured as follows.

400 kV side was measured on29-03-19

Rphase - 0.61 ῼ , Y phase - 0.76ῼ , B phase - 0.58 ῼ

230 kV side was measured on 29-03-2019

Rphase - 0.47 ῼ , Y phase - 0.86ῼ , B phase - 0.68ῼ

The resistive leakage current for the LA's was also measured and the readings are as

follows.

400kV side was measured on 29-03-2019 and the values are as follows .

R phase - 73 μA , Y phase 90 μA , B phase - 92 μA .

230kV side was measured on 22-03-2019 and the values are as follows

R phase - 238 μA , Y phase - 330 μA , B phase 401 μA.

After the incident on 07-05-19 the resistive leaksge current was again measured on

13-05-2019 and the values are as follows.

400kV Side

R phase - 91 μA , Y phase - 116 μA , B phase - 105 μA

230 kV side

R phase - 297 μA , Y phase - 318 μA , B phase - 385 μA

2) Time synchronization of one series of relays completed. The time synchronization

of balance relays will be completed by August 2019.

Pending

84/III/12 Tripping of 400 kV Simhadri-

Kalpakka line-3

12-05-2019 at

18:33 hr.

R-phase to earth fault. Line did not attempt auto-

reclose

1. It was noted that no representative of NTPC

(Simhadri) attended the meeting.

2.NTPC (Simhadri) to submit a detailed report

regarding non-operation of A/R at Simhadri end and

Remedial measures taken for the same.

NTPC(Simhadri) Yet to be informed Pending

85/II/19 Tripping of 400kV JSW-

Guttur line

02-06-2019 at

18:17 hrs

Line tripped due to OV St-1 protection operation at

JSW end and DT was sent to Guttur end. At Guttur

end B ph voltage was observed to be lesser comparing

to R ph and Y ph(Vr-249kV, Vy-255kV and Vb-

230kV).

JSWEL is recommended to monitor the B-ph CVT of

400kV JSWEL-Guttur line (due to lower B-ph voltage

compared to other two phases). The same shall be

replaced if the issue persists.

JSWEL Yet to be informed Pending

85/II/21 Tripping of 400kV JSW -

Guttur line and 400 kV

Kaiga - Guttur line-2

05-06-2019 at

18:27 hrs

Y-phase to earth fault occurred in 400kV Kaiga-Guttur

line-2. A/r was successful at Guttur end. At Kaiga end

A/r was not attempted and breakers got tripped due to

operation of Pole discrepancy (1.65 Sec). 400kV JSW-

Guttur line tripped on operation of over-voltage at

Guttur and direct trip was received at JSW. From DR

of Guttur, it is observed that there was swell in R & Y

phase voltage for few cycles

1. NPCIL (KGS) is recommended to identify the issue

related to unsuccessful A/R attempt of 400kV Kaiga –

Guttur line and non-opening of R-pole CB. It is

recommended to check the healthiness of all breakers

including breaker timing.

2. Time synchronization of DR and EL at Kaiga end

shall be ensured.

NPCIL (KGS) Yet to be informed Pending

Annexure-IV

Page 47 of 48

85/III/14 Tripping of 400kV Kaiga-

Guttur line-2

16-06-2019 at

19:20 hrs

R-phase to earth fault. Auto-reclose attempt at Guttur

end was not successful as fault was persistent in

nature. Attempt for A/r could not be established from

Kaiga end EL

1. NPCIL (KGS) is recommended to identify the issue

related to unsuccessful A/R attempt of 400kV Kaiga –

Guttur line and non-opening of R-pole CB. It is

recommended to check the healthiness of all breakers

including breaker timing.

2. Time synchronization of DR and EL at Kaiga end

shall be ensured.

NPCIL (KGS) Yet to be informed Pending

85/IV/7 Tripping of 400kV

Ramadugu-Singareni line

11-06-2019 at

08:24 hrs

Line tripped due to Direct Trip receive at Ramadugu

end

Singareni STPP is recommended to submit a detailed

report regarding sending of DT from singareni end that

resulted in tripping of 400kV Ramadugu-Singareni

line.

Singareni TPP Yet to be informed Pending

Annexure-IV

Page 48 of 48

Sl.No. Element Name Outage date/time Revival date/time Reason for outage Sender/ Receiver Remedial Measures/ Actions taken Remarks

1 400KV-BPS-TUMKUR-2 17-03-2019/16:17:00 R-Y FAULT KPTCL To-be-discussed

2 400KV/220KV RAMAGUNDAM-ICT-2 05-04-2019/19:56:00 05-04-2019/23:26:00BUS BAR PROTECTION

OPERATEDNTPC To-be-discussed

3 220kV Dindi-Srisailam line-2 17-05-2019/11:44:00 17-05-2019/16:33:00 TRIPPED ON R-N FAULT

TSGENCO/ TSTRANSCO

[Pending with TSGENCO]

"TSTRANSCO:

It is 220kV Dindi-Srisailam-2 feeder.

A/R successful at Dindi end."

4 400KV-BTPS-HIRIYUR-2 02-06-2019/18:16:00 TRIPPED ON Y-N FAULT

KPCL/ KPTCL

[Pending with KPTCL]

"KPCL: Line tripped on Zone-2, ""C"" phase

to earth.

Remedial Measures: Line Charged on

03.06.2019 at 09:47Hrs from BTPS end

"

5 400KV-TALGUPPA-HASSAN-1 05-06-2019/23:59:00 06-06-2019/00:32:00R Phase distance protection

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

6 132KV-KONAJE-MANJESWAR-1 06-06-2019/05:45:00 EARTH FAULT RELAY OPERATED KPTCL/ KSEBLKSEBL:

Feeder not trippped at Manjeswar end

7 400KV-KUDGI_PG-NARENDRA-1 07-06-2019/22:47:00 07-06-2019/23:00:00 Y-N FAULT PGCIL(SR-II) To-be-discussed

8 400KV-GUTTUR-JINDAL-1 11-06-2019/17:24:00 11-06-2019/19:00:00BUS BAR PROTECTION

OPERATEDKPTCL/ JSWEL To-be-discussed

9 400KV/220KV GUTTUR-ICT-2 11-06-2019/17:24:00 11-06-2019/19:04:00BUS BAR PROTECTION

OPERATEDKPTCL

On 11.06.19 at 17:23 hrs 400KV Kaiga-

Guttur-1(Line-1) tripped at Kaiga end on

receipt of DT from Guttur end. As per

KPTCL information, during ground fault

testing in bus bar panel at Guttur end, trip

command was extended to bus bar

protection and all connected elements

were tripped. Direct trip was extended to

Kaiga end CB. No event is recorded at

Kaiga end. Kaiga- Guttur-1 (Line-1) was

taken into service on 11.06.2019 at

20:13hrs vide CPCC-06/234 and SRLDC -

06/627.

Issue is belonging to KPTCL

10 400KV/220KV GUTTUR-ICT-1 11-06-2019/17:24:00 11-06-2019/18:10:00BUS BAR PROTECTION

OPERATEDKPTCL To-be-discussed

11 400KV-GUTTUR-HIRIYUR-2 11-06-2019/17:24:00 11-06-2019/18:42:00BUS BAR PROTECTION

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

Pending Remedial Measures/ Actions taken for the Critical Tripping Incidents (as on 01.08.2019)

Annexure-V

Page 1 of 4

12 400KV-KAIGA-GUTTUR-1 11-06-2019/17:24:00 11-06-2019/20:13:00BUS BAR PROTECTION

OPERATEDNPCIL (KGS)/ KPTCL To-be-discussed

13 400KV-DONI-GUTTUR-1 11-06-2019/17:24:00 11-06-2019/18:01:00BUS BAR PROTECTION


14 400KV-GUTTUR-HIRIYUR-1 11-06-2019/17:24:00 11-06-2019/18:35:00BUS BAR PROTECTION

OPERATEDKPTCL/ PGCIL (Sr-II) To-be-discussed

15 400KV-NELAMANGALA-TALGUPPA-1 12-06-2019/18:24:00 12-06-2019/20:44:00 EMERGENCY WORK KPTCL To-be-discussed

16 400KV-GUTTUR-HIRIYUR-1 12-06-2019/17:00:00 12-06-2019/17:19:00 DT received from Guttur KPTCL/ PGCIL (SR-II) To-be-discussed

17 400KV-TALGUPPA-HASSAN-1 12-06-2019/14:38:00 12-06-2019/21:31:00 INSULATOR FLASH OVER KPTCL/ PGCIL (SR-II) To-be-discussed

18 400KV/220KV HOODY-ICT-2 16-06-2019/19:20:00 16-06-2019/20:51:00OVER FLUX PROTECTION RELAY


19 400KV-KAIGA-GUTTUR-2 18-06-2019/02:53:00 R-N FAULT NPCIL(KGS)/ KPTCL To-be-discussed

20 220KV-AMBEWADI-XELDEM 23-06-2019/16:09:00 TRIPPED ON C-N FAULT KPTCL To-be-discussed

21 220KV-CHILLAKALLU-NARKETPALLI-1 25-06-2019/17:17:00 25-06-2019/17:34:00 TRIPPED ON R-N FAULT

APTRANSCO/ TSTRANSCO

[pending with TSTRANSCO/

TSGENCO]

APTRANSCO: Feeder tripped on R-Phase to

ground, Zone-2 fault. Line charged after

taking permission from SLDC. Fault

distance of 81.68KM falls in TSTRANSCO

juridiction.

TSTRANSCO: Line Patrolling done and no

fault found. Substation belongs to

TSGENCO

What protection operated at

Narketapalli? Status of A/R in

the line?

22 400KV-BHADRAVATHI-RAMAGUNDAM-1 26-06-2019/16:29:00 26-06-2019/18:35:00 RELAY MALOPERATION NTPC (RMGD)/ WR To-be-discussed

23 400KV-SALEM-DHARMAPURI-1 29-06-2019/15:43:00 29-06-2019/17:03:00 phase to phase fault PGCIL (SR-II) To-be-discussed

24 220KV-Talapalli-NAGARJUNASAGAR TS 30-06-2019/11:03:00 30-06-2019/11:36:00 TRIPPED ON B-N FAULTAPTRANSCO/ TSGENCO [

pending with TSGENCO]

APTRANSCO: Feeder not tripped at

Tallapalli end.

APTRANSCO: The feeder "Nagarjuna sagar-

AP" may be changed as "Tallapalli".

2.Feeder not tripped at Tallapalli end.No

carrier received from Nagarjuna Sagar -TS

end due to PLCC problem at TSGENCO

end.

25 132KV-KONAJE-MANJESWAR-1 07-07-2019/12:49:00 DISTANCE PROTECTION KPTCL/ KSEBLKSEBL: Supply failed at 110kV Manjeswar

substaion

Annexure-V

Page 2 of 4

26220KV-KOTHAGUDEM_TPS-

LOWER_SILERU-108-07-2019/10:45:00 08-07-2019/11:18:00 TRIPPED ON B-N FAULT TSGENCO/ APGENCO

TSGENCO: On 08.07.2019 at 10:45 hrs

220KV KTPS-Lower Sileru Feeder was

tripped on Distance Protection at a

distance of 49.31KMs from KTPS end. After

getting clearance from SLDC, line charged

at 11:18 Hrs. Line stood ok.

27 400KV/110KV SHOLINGANALLUR-ICT-1 09-07-2019/14:47:00 09-07-2019/20:25:00TRIPPED ON BUCCHOLZ RELAY

OPERATIONTANTRANSCO To-be-discussed

28400KV-CUDDAPAH-NAGARJUNASAGAR_PG-

112-07-2019/14:31:00 12-07-2019/15:10:00

TRIPPED DUE TO B-N LINE

FAULTPGCIL (SR-I) To-be-discussed

29 132KV-KONAJE-MANJESWAR-1 14-07-2019/10:25:00 14-07-2019/10:49:00 TRIPPED ON B-N FAULT KPTCL/ KSEBL To-be-discussed

30220KV-KOTHAGUDEM_TPS-

LOWER_SILERU-114-07-2019/13:39:00 14-07-2019/13:55:00 TRIPPED ON R-N FAULT TSGENCO/ APGENCO To-be-discussed

31 400KV-NEYVELI_TS_II-NEYVELI_TS1_EXP-1 17-07-2019/21:39:00 17-07-2019/23:26:00 POLE DISCREPANCY NLCIL To-be-discussed

32400KV-SRISAILAM_LEFT_BANK-

SATTENPALLI20-07-2019/07:44:00 20-07-2019/17:53:00 TRIPPED ON B-N FAULT TSGENCO/ APTRANSCO To-be-discussed

33 400KV-KAIGA-GUTTUR-2 22-07-2019/17:47:00TRIPPED DUE TO B-N LINE

FAULTNPCIL (KGS)/ KPTCL To-be-discussed

34220KV-KOTHAGUDEM_TPS_V-LOWER_SILE

..23-07-2019/11:48:00 23-07-2019/16:20:00

TRIPPED DUE TO B-N LINE

FAULTAPGENCO/ TSGENCO To-be-discussed

35 400KV-YELHANKA-NELAMANGALA-1 23-07-2019/12:09:00operation of gas chamber

protectionKPTCL/ PGCIL (Sr-2) To-be-discussed

36 400KV-HOODY-YELHANKA-1 23-07-2019/12:09:00operation of gas chamber

protectionKPTCL/ PGCIL (Sr-2) To-be-discussed

37 220KV-KADAKOLA-KANIYAMPETTA 23-07-2019/10:49:00 23-07-2019/12:26:00 RELAY MALOPERATION KSEBL/ KPTCL To-be-discussed

38 400KV-HINDUJA-KV_KOTA-1 23-07-2019/09:04:00 TRIPPED ON B-N FAULT HNPCL/ APTRANSCO To-be-discussed

39 400KV-DICHPALLY-NIZAMABAD-2 25-07-2019/14:19:00 25-07-2019/14:58:00 RELAY MALOPERATION TSTRANSCO/ PGCIL (SR-2) To-be-discussed

40400KV-SRISAILAM_LEFT_BANK-

SATTENPAL..26-07-2019/11:39:00 26-07-2019/13:19:00 MAL-OPERATION TSGENCO/ APTRANSCO To-be-discussed

41400KV/110KV SUNGAVARACHATRAM-ICT-

326-07-2019/14:07:00 26-07-2019/15:15:00 EXTERNAL PROTECTION TRIP TANTRANSCO To-be-discussed

42400KV/110KV SUNGAVARACHATRAM-ICT-

426-07-2019/14:10:00 26-07-2019/16:30:00 EXTERNAL PROTECTION TRIP TANTRANSCO To-be-discussed

43 220KV-THENI-MOOZIYAR-1 27-07-2019/12:24:00 27-07-2019/12:47:00TRIPPED ON SINGLE PHASE TO

GND FAULTKSEBL/ TANTRANSCO To-be-discussed

44 400KV/220KV TALGUPPA-ICT-2 27-07-2019/16:27:00 27-07-2019/17:16:00 MALFUNCTIONING OF OCR KPTCL To-be-discussed

Annexure-V

Page 3 of 4

45 132KV-KONAJE-MANJESWAR-1 28-07-2019/10:29:00 28-07-2019/14:26:00 DISTANCE PROTECTION KSEBL/ KPTCL To-be-discussed

46 230KV-NEYVELI_TS_II-KARAIKAL-1 29-07-2019/18:36:00 29-07-2019/20:18:00 TRIPPED ON R-N FAULT NLCIL/ PGCIL (SR-2) To-be-discussed

47 400KV-TIPPAPUR-JANAGAON-2 31-07-2019/19:00:00 31-07-2019/20:36:00 DT RECEIVED TSTRANSCO To-be-discussed

48 230KV-NEYVELI_TS_II-KARAIKAL-1 31-07-2019/07:08:00 31-07-2019/20:09:00 CVT Problem NLCIL/ PGCIL (SR-2) To-be-discussed

Annexure-V

Page 4 of 4

Documents

documents through DMNS application. The updated version of PSCT software, PSCT manual, PSCT bus breaker model (PSCT case file) for SR region and excel sheet containing statewise element