Minutes of the 42nd
PCSC Meeting held on 26-03-2015 Page 1
SOUTHERN REGIONAL POWER COMMITTEE BENGALURU
Minutes of the 42nd
Meeting of Protection Coordination Sub- Committee
(PCSC – 42) of SRPC held on 26.03.2015
1. Introduction
The 42nd
meeting of Protection Coordination Sub-Committee (PCSC) was held on 26th
March,
2015 in the Conference Hall of Southern Regional Power Committee, Bangalore. The list of
participants is enclosed at Annexure-I.
Shri S.R.Bhat, Member Secretary (MS), SRPC welcomed the Members and Participants to the
meeting and briefed them on the following points:
Non-furnishing of tripping details including Disturbance Recorder/ Sequential Event Logger
output in compliance of Regulation 5.2 (r) of IEGC. Fortnightly, under 1.5 (r) of IEGC,
SRLDC is submitting the non-compliance list of trippings for which trip details are pending,
partly submitted or delayed. Members were requested to comply with the Grid code and
CEA Standards in this regard, and furnish/ upload the tripping details within stipulated time.
With reference to Petition No. 374 filed by TANTRANSCO before Hon’ble CERC, all
Southern Region Constituents were requested to adhere to the timeline of 31.03.2015 in
filing the status of implementation of protection audit recommendations in their respective
States to the Commission.
Attention was drawn to NLDC/ SRLDC letter regarding violation of protection standard
(delayed fault clearing) for the month of February, 2015 in case of tripping of inter regional
lines viz., 220 kV Ambewadi – Ponda, 220 kV Talandege – Chikkodi. KPTCL was
requested to take suitable remedial actions to prevent tripping of these lines.
Frequent trippings in NTECL, Vallur - NCTPS area due to insulator related problems on the
transmission towers. TNEB was requested to expedite replacing faulty insulators on the
transmission towers in Vallur and Kalvindapattu areas. With reference to the Meeting held
at Vallur-NTECL plant, the need for implementing and continuing with the measures
recommended such as hot-line washing of the insulators were stressed.
SPS issues discussed in the 105th
OCC meeting of SRPC were briefed; the first issue was
w.r.t. KPTCL’s suggestion of routing SPS trip signal through Kolar-Chintamani-Mallur to
minimize the travel time while restoring SPS-shed loads. The second issue pertained to
modification of SPS at Trichur so as to take Palakkad ICT loading also into account.
ED, SRLDC also expressed the need for devising a SPS scheme for Krishnapatam
Minutes of the 42nd
PCSC Meeting held on 26-03-2015 Page 2
generation by APGENCO/ APTRANSCO.
22. Confirmation of the Minutes of the 41st PCSC meeting held on 26-02-2015
SE (Protection), SRPC stated that the Minutes of the 41st meeting of the PCSC had been
circulated vide SRPC letter No. SRPC/SE-III/ PCSC·41/ 2015/ 1702 – 133 dated 16.03.2015.
However, as it was noticed that a typographical error had occurred in the recommendations
relating to the grid disturbance on 220 kV Sedam –Tandur line given at Sl. No. I (4) of the
Annexure-II to the Minutes, the recommendations given therein were corrected as follows:
KPTCL to provide Bus bar and LBB protections for 220 kV bus at Sedam S/s. KPTCL to implement A/R feature on 220 kV Sedam-Tandur inter-state line.
With this, the Minutes of the 41st meeting of the PCSC were confirmed.
3. Details of Grid Disturbances (GD’s), Grid Incidents (GI’s), Line Trippings due to PLCC
mal- operation, Auto-Reclose non-operation
The trippings due to GD’s, GI’s, PLCC mal-operation and Auto–Reclosure failure/non-
operation that had occurred during the period February - March, 2015 were discussed in the
Meeting. The deliberations and recommendations of the PCSC-forum are enclosed at
Annexure–II.
4. Status of pending PCSC recommendations
The status of implementation of pending PCSC recommendations were discussed in the
meeting. The constituents have been requested to kindly submit the status of their compliance
latest by 24.04.15. The updated status of the same as on 16.04.2015 is enclosed at
Annexure III.
5. Remedial measures/ Action taken for the tripping incidents of the transmission elements
under forced outage
The tripping incidents of the transmission elements under forced outage for which the remedial
measures/ actions taken still awaited were discussed in the Meeting. The Constituents have
been requested to kindly furnish the remedial measures/ action taken in time so as to forward
the same to Central Electricity Authority. The updated list of the same as on 16.04.2015 is
enclosed at Annexure-IV.
7. Certificate for Healthiness of Batteries
As per the 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 the monthly certificate for healthiness of batteries, installed
at 220 KV and above voltage level Substations (for power supply to Relays, RTUs and PLCC
equipment) and furnish the same to CEA/ MoP.
With reference to above, the Constituents have been requested to submit the certificate on
Minutes of the 42nd
PCSC Meeting held on 26-03-2015 Page 3
healthiness of batteries on monthly basis (i.e. status for a month may be sent by the 7th
day
of the succeeding month) to SRPC.
The Constituents have been requested to furnish station-wise status 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)
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 February, 2015 has not been received from the following
SR-Constituents:
TSGENCO (Thermal & Hydro), JSWEL & GMR.
9. Dynamic study data submission
All SLDCs have been requested to direct the embedded IPPs connected at 220 kV and above
voltage level to submit completed dynamic study format to SRPC, Secretariat. Constituents
have been requested to submit the Dynamic study data at the earliest.
10. Network configuration changes
As per the information furnished by SR-Constituents to the OCC forum in their 105th
Meeting held on 10.03.2015 (Minutes circulated on 28.03.2015), it is observed that no
network configuration changes (additions/ deletions/ modifications of transmission elements)
took place in southern grid during the month of February, 2015.
KPTCL vide their mail dated 25.03.2015 informed that the following new transmission
elements had been added in the month of March, 2015.
Sl.No.
Name of the Element
Connected Sub Station
Date and time of Commissioning
Remarks
1 220kV Hiriyur-Gowribidanur
D/C line
Hiriyur PGCIL and Gowribidanur SS
4.3.2015 at 21.10 and 21.15Hrs
Load taken on 9.3.2015 at 21.22
and 21.26Hrs
2 63MVAR Bus Reactor 400kV SS Guttur 23.03.2015 at 15.57Hrs
Minutes of the 42nd
PCSC Meeting held on 26-03-2015 Page 4
11. Compliance of Hon’ble CERC Orders
11.1 Petition No. 146/MP/2013 with I.A. 36/2013: Order dated 20.02.2014
Compliance of Regulations 5.2 (r) of the Grid Code: Issue regarding non-
furnishing of FIR / Trip Analysis Report, EL, DR, etc. was also
highlighted. It is pointed out that the above reports are to be submitted /
uploaded on SRLDC web application within 24 hours as mandated under
IEGC / CEA Regulations.
Implementation of Phase-I and Phase-II of Protection Audit
Recommendations: All the constituents are requested to submit the updated
status of the compliance (those who have not completed recommendations
mentioned in the Phase I and Phase II) to SRPC Secretariat at the earliest.
The following constituents are to submit the updated status of filing of
petition/affidavit to SRPC Secretariat at the earliest: APTRANSCO.
Compliance of Regulations 5.2 (e) & 5.2 (l) of the Grid Code and Regulation
3(1)(e) of CEA Grid Standards: The constituents are requested to strictly
comply with these provisions by ensuring standard protections systems having
the reliability, selectivity, speed and sensitivity to isolate the faulty equipment
and protect all components from any type of faults, within the specified fault
clearance time and providing protection coordination
Ensuring proper maintenance of transmission lines and adopting best O&M
practices: The constituents are requested to conduct line patrolling regularly
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).
(http://www.srpc.kar.nic.in/website/2014/operation/patrolling.pdf).
11.2 Petition No. 167/Suo- Motu/2012: Order dated 22.02.2014
The Constituents are requested to follow approved protection philosophy
ISTS licensees are requested to submit details of updated distance protection relay
setting of all inter-regional lines to POSOCO & RPCs.
All SLDCs are requested to install/activate sound recording system in their control
rooms within three months from the date of issue of this order.
The Constituents are requested to submit the progress of implementation to
SRPC and SRLDC as specified in the Hon'ble CERC Order.
11.3 Petition No. 263/MP/2012: Order dated 19.12.2013
Constituents are requested to implement the quantum of relief by AUFR and df/dt
relays by identifying additional feeders and keep them functional within one month
of issuing this order.
SLDCs are also requested to map these relays on their respective SCADA
system within three months of issuance of this order.
The Constituents are requested to submit the progress of implementation to
SRPC and SRLDC as specified in the Hon'ble CERC Order.
11.4 Petition No. 374/MP/2014: Date of hearing 15.01.2015
Minutes of the 42nd
PCSC Meeting held on 26-03-2015 Page 5
All Southern Region Constituents had been directed to file the status of
implementation of protection system in their respective system to Hon’ble
CERC by 31.03.2015.
12. Date & Venue of the next Meeting
It is informed that the 43rd
PCSC meeting will be held on 29.04.2015 (Wednesday) at 10.30
hrs at SRPC Secretariat, Bengaluru.
X ------------------------------------------ X ------------------------------------------ X
ANNEXURE- I
1 PCSC-42
ANNEXURE- I
2 PCSC-42
ANNEXURE- I
3 PCSC-42
ANNEXURE- I
4 PCSC-42
ANNEXURE- I
5 PCSC-42
ANNEXURE- I
6 PCSC-42
1 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Grid Occurrences
I. GRID DISTURBANCES (GD):
1 Complete outage of 220kV Sedam substation of KPTCL
(i) Date and Time of Event 15-02-2015 at 14:24 hrs
(ii) Location 220 kV Sedam substation
(iii) Plant and/or Equipment directly involved
(iv) Reported Disturbance / Fault
Fault occurred in 220kV Sedam-Shahpur line
(v) Load Loss 100 MW
(vii) Category GD-1
SLD:
Deliberations:
KPTCL:
The fault occurred in 220kV Sedam-Shahpur line.
At Sahapur end, line tripped on zone-1 distance protection and fault loop R-N was at 23 km.
At Sedam end, distance (in zone-2) and back up protection relays on Shapur line sensed the fault and picked up but before their tripping operation, DC supply was lost and hence relays could not operate. (Earlier it was suspected as mechanical
220 kV
Tandur
(TSTRANSCO)
Sedam (KPTCL)
Raichur Shahpur Humnabad
110 kV
Z-2
Z-2
(sense
only)
Z-1
Z-2
DC supply failure;
no LBB;
bus dead
Z-2
ANNEXURE-II
2 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
latch problem with CB).
Due to absence of LBB protection at Sedam, all remote ends - RTPS lines (1&2) and Tandur line - tripped in Zone-2 distance protection. Since the RTPS, which is the main source, is lost, bus dead/shutdown condition occurred at Sedam.
220 kV Tandur inter-state line was chand-tripped at Sedam.
In Hummnabad and RTPS bays, DC earth fault occurred due to damaged DC cable that resulted in tripping of MCB for main DC supply. It is suspected that due to earth potential rise on account of fault, the faulty DC cables might have got grounded causing DC earth fault that made main DC MCB to trip.
KPCL:
220/110 kV ICTs did not trip at Sedam end due to the fact that 110 kV side of ICTs are radially feeding the lines.
SRLDC:
No B/C is at Sedam and it is a single bus operation.
SLDC should check the status/nature of the faults and the line should not have been charged without identifying the root cause, and attending to it.
DC grounding issue at RTPS bay shall be completed by tomorrow (i.e. 27.03.2015).
A/R to be provided on Sedam –Tandur interstate line.
KPTCL should coordinate with both TSTRANSCO and APTRANSCO to provide A/R feature on the 220 kV Sedam –Tandur and Alipur – Regulapadu inter-state lines.
KSEB:
In general, during shift changeover, positive to earth and negative to earth voltages are being recorded.
Remedial measures taken at Sedam end by KPTCL: DC problem:
o Complete testing of DC circuit was taken up with the help of M/s Tarus, and would be completed by 27.03.2015.
o On line DC e/f locator is being used for troubleshooting. o DC cable problem at Hummnabad bays were attended. o At RTPS bays, the damaged control cables would be replaced by April, 2015 end
after availing LC. o Two lamps have been installed at the substation that would indicate DC
grounding/ earthing problem. o There are 2 batteries and 2 chargers but with only one DC load bus; Changeover
of DC source is being carried out manually. To have dual DC load-bus feature, tendering is under process; tenders have been evaluated; and it would take around 12 months time for execution.
Due to non-availability of carrier, zone-2 time delay of distance relays has been reduced from 0.35 sec to 0.2 sec.
There was no problem in the Tandur bay at Sedam, and CB, 86 relay and other relays were tested and found to be OK.
Tendering for the activities covering protection audit recommendations in 93 substations, viz., LBB protection, Bus bar protection, dual DC supply, A/R feature on interstate lines, etc. is in progress.
Shift Engineers working at Sedam are on contract basis; and they reset main MCB of main DC source once it is tripped; they do not report adequately the problems at the station. They have been instructed to adhere to the standard operating
ANNEXURE-II
3 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
procedures. Recommendations:
KPTCL to provide Bus Bar protection and LBB protection at Sedam S/s and furnish the status of their implementation to PCSC forum.
KPTCL to implement A/R feature on 220 kV Sedam-Tandur inter-state line.
2 Complete outage of 220kV Ambewadi substation of KPTCL
(i) Date and Time of Event 12-03-2015 at 7:51 hrs
(ii) Location 220 kV Ambewadi Substation
(iii) Plant and/or Equipment directly involved
(iv) Reported Disturbance / Fault
Fault in 220kV Ambewadi-Nagjheri line-2
(v) Load Loss Nil
(vii) Category GD-1
SLD:
Deliberations:
KPTCL:
A Y-B-E fault occurred in 220kV Ambewadi-Nagjheri line-2 due to snapping of conductor. The distance protection at both ends sensed the Y-B-E fault on the line. The
breaker at Nagjheri end got tripped and fault was cleared from Nagjheri end. The CB at Amewadi did not trip as it was under lock-out due to low air pressure.
As the 220 kV Ambewadi station is on a single bus operation and LBB protection is not available, it resulted in tripping of remote ends (Nagjheri-1, Narendra-1 & 2) in Zone-2 distance protection.
220/110 kV ICT-1 at Ambewadi station tripped on operation of back up directional earth fault protection on LV side. 220/110kV ICT-2 at Ambewadi
220 kV Ambewadi
Ponda Nagjheri Narendra
110 kV
No trip;
radial Z-1
no trip;
no LBB;
bus dead
Z-2
1 2
Z-1
Z-2
backup
DEF trip
CB
lockout 1 2
under
shut
down
ANNEXURE-II
4 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
station was not in service at the time of disturbance. 220 kV bus at Amewadi became dead because there is no feed from Ponda
(radially fed), Nagjheri (tripped), Narendra (tripped) and 110 kV bus which is fed by Supa HEP (ICT tripped).
Ponda 1 & 2 lines were hand-tripped at Ambewadi.
At Ambewadi, bus isolators have been made ready; bus coupler is ready; PT is yet to be replaced; afterwards split bus would be implemented.
At both the ends of Ambewadi – Ponda line, PLCC equipment have to be provided.
One wave trap is by-passed at Ambewadi; On Narendra and Nagjheri lines PLCC system is in place.
SRLDC: PLCC panels are there at Ambewadi, but protection couplers have to be installed.
A/R is to be provided on Ambewadi – Ponda 1 & 2 lines. KSEB:
In case of low air pressure, CB first goes to alarm stage; and if the air pressure further drops, only then does it go to lock-out stage.
Remedial measures: Operation of the compressor was checked. The issue of no annunciation/ alarm observed during the CB lockout has been
attended. Recommendations:
KPTCL shall provide A/R feature on Ambewadi – Ponda 220 kV D/C inter-state line.
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.
3 Complete outage of Upper Sileru Hydro power station
(i) Date and Time of Event 04-03-2015 at 08:00 hrs
(ii) Location Upper Sileru Hydro Power station (USHPS)
(iii) Plant and/or Equipment directly involved
(iv) Reported Disturbance / Fault
LBB of Unit-4 got operated
(v) Generation/ Load Loss Nil
(vii) Category GD-1
Set up:
USHPS is equipped with 4x60 MW hydro generators, 75 MVA, 220/11kV GTs (four nos.), three 220 kV feeders [Balimela (inter-regional link), Donkarai, and Pendurthy] and one Station Transformer (25 MVA, 220/33 kV).
The station is equipped with two buses named main bus and transfer bus. There is a bus coupler between main and transfer buses and also there is a bus sectionalizer CB on the Transfer bus and bus sectionalizer isolator on Main bus. However
ANNEXURE-II
5 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Transfer Bus is also being used as main bus through Transfer bus sectionalizer CB and Bus coupler CB. Functionally station is operating on single Bus.
Unit-1 & 2 connected to main bus and Unit-3 & 4 connected to transfer bus.
220 kV line feeders and the station transformer (ST) are connected to Main bus.
SLD: Upper Sileru HPS
E
Deliberations:
USHPS, APGENCO:
At the time of de-synchronizing U#4, the B-phase limb of the CB did not open. As a result, PD Relay operated to trigger LBB protection trip of all the CBs (connected to main and transfer buses) and B/C. Hence, 220 kV bus at USHPS became dead.
As the generator protection system of Unit#4 is a static relaying system, the events and disturbances are not available with the station for the above trip.
PD relay setting was kept as 200 msec.
Remedial Measures: o CGL breaker limb control valve C&D roller was found to be faulty and was
replaced with new spare. (It was also noted that the same valve was replaced recently for the same problem occurred earlier).
o LBB scheme was modified in such a way that whenever LBB protections are acted upon G#3/G#4, only G#3, G#4, Transfer bus sectionalizer, and bus coupler are tripped instead of all breakers.
4 Complete outage of Srisailam left bank hydro power station
Main bus
GT:
75 MVA
60 MW
Balimela
G1
G2
G3
G4
60 MW
GT:
75 MVA
Transfer bus
Donkarai
Pendurthy
ST: 25 MVA,
220/33 kV
B/C
B/S
220 kV
ANNEXURE-II
6 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
(i) Date and Time of Event 20-03-2015 at 11:22 hrs
(ii) Location Srisailam Left Bank Hydro Power station
(iii) Plant and/or Equipment directly involved
(iv) Reported Disturbance / Fault
Fault in GIS bus at Srisailam. 400kV
Mamidapalli-1&2, Satenapalli-1&2 and
Kurnool lines tripped on operation of residual
over current protection at Srisailam.
(v) Generation/ Load Loss Nil
(vii) Category GD-1
SLD: SrisailamLB
Deliberations:
TSGENCO:
There was no generation at Srisailam left bank during the incident.
There occurred a fault in 400 kV GIS bus i.e. problem in one of the bus side isolators of the lines.
As the bus bar protection was not available, it was sensed by residual over current protection provided in the distance relay of 400kV lines at Srisailam which in-turn led to the tripping of the line breakers of all 400kV lines (given below) at Srisailam: 400kV Srisailam-Mamidapalli line-1&2 400kV Srisailam-Satenapalli line-1&2 400kV Srisailam-Kurool
Remote ends of Satenapalli-1&2 and Mamidapalli-1&2 lines were holding and they were later hand-tripped.
Residual current
protection trip of lines
GT
Mamidipally Satenapally Kurnool
G1
G2
G3 G4 G5 G6
400 kV (GIS bus)
No generation;
no condenser mode
operation
hand trip
O/V, St-1 trip
Stn.Trf.
ANNEXURE-II
7 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Remote end of Kurnool line tripped on operation of over voltage, state-1 protection.
The residual over current relay mal-operated due to moisture in SF6 gas. The levels of moisture absorbents for the gas checked and refilled. There is no online dew point monitoring system.
No condenser mode of operation is at SSLM-LB.
Numerical Bus Bar protection would be installed in a month. Bus bar protection would be with two zones covering each bus independently.
SRLDC:
In the past, there were leakage current issues (4 times) and O/V issue (1 time).
As there is no shut down request from TSGENCO for SSLM in April/May, it is not clear how the relays would be installed in a month’s time there.
Time frame for commissioning of numerical bus bar protection shall be furnished by 20.04.15.
KSEB:
Bus coupler CB is generally provided with O/C and E/F relay.
SRPC:
TSGENCO has not yet furnished the reasons and remedial measures taken in respect of the grid incident that occurred at SLBHES on 23-01-2015 at 16:10 hrs (discussed in PCSC-41).
Recommendations:
TSGENCO to provide bus bar protection at Srisailam left bank HES, and furnish the time frame for implementation of the same by 20.04.2015.
5 Complete outage of 220 kV Tadikonda substation of APTRANSCO
(i) Date and Time of Event 22-03-2015 at 19:31 hrs
(ii) Location 220/ 132 kV Tadikonda Substation
(iii) Plant and/or Equipment directly involved
(iv) Reported Disturbance / Fault
B-phase CT failure on LV side of 220/132kV ICT-1 at Tadikonda led to complete outage of Tadikonda station.
(v) Generation/ Load Loss Load loss = 200 MW
(vii) Category GD-1
SLD: Tadikonda
ANNEXURE-II
8 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Deliberations:
APTRANSCO:
Triggering incident was the failure of B-ph CT on LV side of 100 MVA, 220/ 132 kV ICT -1. Due to this, there was a slow developing fault on the LV side of ICT-1, and it resulted in the tripping of the following elements: 100 MVA, 220/ 132 kV ICT-1 tripped on differential protection 100 MVA, 220/ 132 kV ICT-2 tripped on over current protection 160 MVA, 220/ 132 kV ICT-4 tripped on over current protection 220 kV Bus coupler tripped on over current protection 220 kV Tadikonda – VTS line 1 tripped at VTS end on distance protection, zone-
4.
As the 220kV Ongle-Tadikonda line was kept idle charged from Ongole during the instance, it led to complete outage of Tadikonda Substation.
VTS line impedance is around 10 ohm per circuit and that of Ongole is around 4
ohm. As the parallel impedance of circuits and ICTs between relaying point and the fault point seen at the relaying point is around 10.5 ohm, the zone-4 might have got operated at VTS end on 220 kV Tadikonda – VTS line 1.
The 100 MVA, 220/ 132 kV ICT-3 and 220 kV VTS –Tadikonda line 2 did not trip during the incident.
There were no numerical relays at Tadikonda, as such no DR/EL could be furnished.
The distance protection philosophy being followed by APTRANSCO was explained as follows: Z1 (forward) –> 85 % of Protected line (Instantaneous)
Bus-I
Bus-II
220 kV
132 kV
Guntur
Nallapadu
Marripalem
Piduguralla
Tadepalli
VTS-1
VTS-2
Ongole
B/C
(line idle charged)
CT fail
1
2
3
4
Z-4 trip
charged)
Z-4 trip
charged)
Diff. trip
charged)
O/C trip
charged)
O/C trip
charged)
2 x 31.5 MVA
charged)
33 kV O/C trip
charged)
ANNEXURE-II
9 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Z2 (forward) – > Protected line + 50 % of Shortest Line (0.3 sec) Z3 (forward)– > Protected line + 120 % of Shortest Line (0.6 sec) Z4 (forward) –> Protected line + 120 % of Longest Line (0.9 – 1.2 sec) Z5 (reverse) –> 25 % of Z1 (1 sec)
Remedial measures: It has been proposed to reduce O/C relay setting of the ICT’s to 0.9 sec from
the present 1.0 sec after checking the fault level calculations..
Recommendations:
Reasons for non-tripping of ICT-3 along with remedial measures taken shall be furnished by APTRANSCO to PCSC forum.
II. GRID INCIDENTS (GI):
Sr.
No.
Details of Events Date and Time Reason Category
1 Tripping of 400kV Coastal-
Tuticorin PS line 19-02-2015 at
16:37 hrs
Line tripped at Coastal end only
due to suspected PLCC mal-
operation and was holding from
Tuticorin PS end. Running Unit at
Coastal energen also got tripped
during the event.
GI-2
Deliberations: CEPL:
The 400 kV CEPL – Tuticorin PS line tripped at CEPL end due to DT receipt from Tuticorin PS.
When the tie-CB trips at Tuticorin PS, it should not be extended to CEPL.
SRLDC:
400kV CEPL-Tuticorin PS line tripped at 16:37 hrs Line tripped at Coastal end only, and was holding from Tuticorin PS end. During the instance, 400kV NTPL-Tuticorin PS was under shutdown due to
insulator replacement works. Running Unit at CEPL also got tripped during the event.
Coastalgen TPS NTPL
DT
hand trip
under S/D
unit trip
ANNEXURE-II
10 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Subsequently, 400kV Coastal-NTPL line was manually tripped from Coastal end at 16.37 hrs.
End-to-end testing may be carried out to ascertain PLCC operation.
In addition, level measurement and wiring check have also to be carried out.
Recommendations: PLCC end-to-end testing shall be carried out by CEPL and Tuticorin PS (PGCIL-SR II) by
06.04.2015.
2 Tripping of 220kV
Chikodi-
Talandage and
220kV Chikodi-
Mudshingi line
20-02-2015 at
06:40 hrs
Lines tripped during test charging 220kV
Chikodi-Belgaum line-2 from Chikodi
end.
GI-1
Deliberations:
KPTCL:
At 3.20 hrs, the 220kV Belgaum-Chikodi-2 line tripped on distance relay,zone-1 (Fault loop RN, 63.7Kms)
After approval from LDC, the 220KV Belgaum-Chikodi-2 line test charged at 6.40Hrs in the morning. However, due to insulator decapping, Mudashinge, Talandage lines tripped. It was observed that the Chikkodi end CB on Belgaum – Chikkodi 2 line did not open during the incident.
Chikkodi- Mudashinge line tripped in Zone 3 at Mudashinge end (DPR,zone-3, R phase, Dist- 125.5Kms, L1- 1.49KAmps, L2-0.15KA, & L3-0.29KA). Breaker at Chikodi end was in closed condition.
220KV Chikkodi-Talandage line tripped at Chikkodi end on DEFR (due to problem in the directional element, the relay had been made non-directional). Talandage end CB did not trip.
Remedial measures: At Chikkodi, VXL make old C&R panels are in service. Relays are giving frequent
troubles. Hence 2 numbers of alternate C&R panels are arranged at Chikkodi. Replacement of C&R panels of Mudashinge and Talandage lines is scheduled during 18th, 19th, and 20th of April, 2105.
SRLDC:
All inter-state lines are being monitored by NLDC.
PLCC problem along with A/R feature have to resolved.
Recommendations: KPTCL to provide A/R feature on the 220 kV Chikkodi – Talandage, and 220 kV Chikkodi –
Chikkodi
Belgaum
Mudshinge
Talandage
1
2
Z-3
DEFR
trip due to insulator
decapping
ANNEXURE-II
11 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Mudashinge inter-state lines. KPTCL to carry out E/F relay coordination for Chikkodi - Talandage and Chikkodi –
Mudashinge lines in coordination with Maharashtra.
3 Outage at
Regulapadu
station of
APTRANSCO
21-02-2015 at
00:49 hrs
Y-Ph Metering PT failed at 220KV
Ragulapadu Substation. Fault got cleared
by tripping of lines from remote ends.
Deliberations:
The cause of the incident was the failure of Y-Ph metering PT at Regulapadu.
The 220 kV Regulapadu – Gooty (AP) line tripped at Gooty (AP) in Zone-2.
The 220 kV Regulapadu – Alipura line tripped at Alipura in Zone-2. SRLDC:
As per synchrophasor data at 400 kV Gooty S/S, it was observed that two faults had occurred, first in R-phase and 2nd in R-B phase.
Status of bus coupler breaker and Bus bar protection at Regulapadu station was enquired.
Alipura – Regulapadu being an inter-state line, A/R feature should be put in place. APTRANSCO:
Fault was cleared at remote ends due to non-availability of BB protection.
Provision has been given in DPR for addressing single bus operation issue, and BB protection issue.
SRPC:
The status of features such as PLCC, A/R, double bus system, LBB protection, Bus bar protection, and the protection philosophy being followed (Main-1/ Main-2/ Back-up), for all inter-state and inter-regional lines shall be obtained from the Constituents.
Recommendations: APTRANSCO to furnish the remedial measures taken in consequent to the tripping
incident along with the status of bus bar protection and bus coupler at Regulapadu S/s. A/R feature to be enabled on Regulapadu – Alipuira 220 kV inter-state line.
4 Tripping at 230kV
Theni substation
22-02-2015 at
13:12 hrs
Fault had occurred in 230kV Theni-
Chekanoorani feeder.
GI-1
Regulapadu
Alipura
Gooty
Z-2
Z-2
metering PT
ANNEXURE-II
12 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
5 Tripping of 400/220kV
ICT-2 at Bidadi
substation
22-02-2015 at
16:58 hrs
ICT-2 got tripped on operation of backup
protection during B-phase LA failure of
ICT-1 at Neelamangala station of KPTCL
GI-2
Deliberations:
As per FIR/TR of Bidadi (PGICL, SR-II), B-phase LA failed on 400 KV side of ICT-1 at Nelamangala Substation. As Bidadi ICT-2 also fed this fault from 220 kV side, it tripped on backup over current protection (on both HV and LV sides). PGCIL:
230 kV directional O/C relay did not get voltage input from bus CVT because of its fuse blown condition, hence the relay mal-operated.
SRLDC:
Reason for operation of back-up protection for ICT-2 at Bidadi was not clear as there was no delayed clearance of the fault.
PGCIL to give report on the incident.
A visit to Bidadi station should be made to know the details. SRPC:
PSAG visit shall be made to ascertain the status of the protection system at Bidadi s/s. Recommendations:
PGCIL (SR-II) to submit a detailed report on the incident along with remedial measures taken to PCSC forum in a week’s time.
6 Tripping of ICT-1 at
Nelamangala
substation of KPTCL
22-02-2014 at 16:58
hrs on
ICT-1 at Nelamangla station got tripped
due to failure of B-phase lightening
arrester.
Deliberations:
A Y-Ph to ground fault occurred on Theni- Chekanoorani feeder and tripped at 13.10 hrs. (ref: FIR of Theni)
The line tried to Auto-Reclose, but due to the persistent nature of the fault, the line was permanently tripped at both ends. However, due to the problem in Y-Ph limb of Theni end CB, LBB Protection operated at 230 kV bus of Theni S/s. As Theni is operating on single 230 kV bus, all the connected 230 kV lines also got tripped.
Remedial measures: Faulty limb of CB has been attended and replaced by TANTRANSCO. Theni – Sabarigiri (Mooliyar) feeder normalized at 13:58 hrs. on 22.02.2015. Theni – Checkanoorani feeder normalized after testing the breaker on 22.02.2015 at
22:11 hrs. SRLDC:
Timeline for provision of bus coupler breaker at Theni S/S may be provided. SRPC:
As per DR of Theni, the fault took place at 13.04.46 hrs. Time synchronization with GPS may be checked at Theni S/S.
ANNEXURE-II
13 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Deliberations:
KPTCL:
ICT-1 at Nelamangala S/S got tripped on differential protection due to failure of B-phase
lightening arrester.
Remedial measures:
Failed lightening arrester was replaced
SRLDC:
The fault was cleared in time.
7 Tripping of 400kV
Jeypore-Gazuwaka line-
1&2 and tripping of
HVDC back to back pole-
1&2 at Gazuwaka
23-02-2015 at
13:34 hrs on
HVDC pole-1 got tripped due to failure
of 4 no. power supply card. HVDC
pole-2 tripped on DC low voltage trip.
400kV Jeypore-Gazuwaka line-1&2
tripped due to operation of Over voltage
protection at Gazuwaka end.
GI-2
Deliberations:
As per FIR submitted by HVDC, Gazuwaka station, power flow on pole-2 was being reduced as per instructions from NLDC due to system constraint in eastern region.
HVDC pole-1 got tripped at 13:33:49 hrs due to failure of 4 no. power supply card of YDUV valve.
400kV Jeypore-Gazuwaka line-1&2 tripped at 13:39:57 and 13.39:58 hrs respectively due to operation of Over voltage, Stage- I protection at Gazuwaka end due to load throw – off on tripping of few lines on eastern side. (and DT sent to Jeypore end)
HVDC pole-2 tripped at 13:34:00 hrs on DC low DC voltage trip due to tripping of both 400kV lines.
PGCIL (SR-I):
It was observed that there were voltage fluctuations at Jeypore at the instant of failure of control supply cards, and the matter has been referred to OEM (M/s ABB) for remedy.
It was further observed that voltage fluctuations on Jeypore-Gajuwaka line were being experienced whenever FSC was in service/ put into operation at Jeypore end.
Remedial measures: The failed control supply cards were replaced. The matter has also been taken up with M/s ABB.
East bus South bus
Jyepore (Odisha)
1
2
P2
HVDC Pole-1 trip
due to ‘PS card
failure'
FSC
P1
Gajuwaka HVDC B2B (AP)
HVDC Pole-2 trip
due to ‘low DC
voltage’
AC lines tripped
due to O/V
ANNEXURE-II
14 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
SRLDC:
As per the present design, FSC at Jeypore would get disabled/ bypassed if the power flow on Jeypore-Gajuwaka line goes below 300 MW. However, if the PGCIL (SR-I) wants this limit to be changed, the same should be intimated to NLDC.
Recommendations: PGCIL (SR-II) to submit the report of M/s ABB’s on preventing supply card failures.
8 Tripping of HVDC
Talcher-Kolar pole-1
23-02-2015 at 15:37
hrs
Pole 1 of Talcher-Kolar HVDC
Transmission system tripped on receipt
of ESOF (Emergency Switch-off) from
Talcher
GI-2
Deliberations:
SRLDC:
Pole 1 of Talcher-Kolar HVDC Transmission system tripped on receipt of ESOF (Emergency Switch-off) from Talcher.
Antecedent Bipole power: 1000 MW
It changed over to Metallic Return mode, and the final DC power in Pole 2 settled at 997 MW (Talcher AC side).
Since Pole 2 compensated for the power and as there was no power loss, SPS was not triggered which is as per design.
PGCIL (SR-II):
As per their information, ESOF signal was received at Kolar due to filter protection operation at Talcher.
Filter protection at Kolar might have got operated due to oil leakage in filter capacitor
banks. Recommendations:
PGCIL (SR-II) to submit a report on the reasons for operation of filter protection at Talcher, and subsequent receipt of ESOF at Kolar.
9 Tripping of 765/400kV
ICT-1 at Raichur
25-02-2015 at
18:32 hrs
ICT-1 at Raichur tripped due to mal-
operation of contact multiplication relay
GI-2
Deliberations:
PGCIL (SR-II):
ICT-1 got tripped on operation of spare ICT top oil temp protection.
The tripping got extended via 30K CMR relay. This relay did n’t have any cable from the field as no TBs were identified for top oil temp protection in TBEA Xmer. However, the CMR operated and resulted in extending Binary Input signal to P645 and caused operation of Gr-A & Gr-B relays tripping ICT-1.
There is an NRV between conservator and Tank. Recommendations:
PGCIL (SR-II) to disable the top oil temperature protection in the concerned relay at Raichur-PG and Tiruvalam-PG also.
ANNEXURE-II
15 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
10 Tripping of ICT-3 at
Gajwel substation
27-02-2015 at 2:32
hrs
ICT-3 tripped due to operation of over
current relay
Deliberations:
TSTRANSCO:
The insulation of the cable laid from tie-CT to relay panel (leads pertaining to Y-phase tie-CT) got earthed at the marshalling box near the cable gland causing circulating currents in the neutral. This caused HV side back-up over-current relay to operate tripping ICT-3.
Remedial measures: The cable which was causing undesirable tripping was replaced on 28th February-
2015 and the currents displayed in the numerical relay were found to be balanced and same as that of LBB and differential relays.
SRPC:
The cause of cable failure may be investigated.
EL uploaded was the same as DR.
11 Tripping of 220 kV
Chikodi-Talandage and
Chikodi-Mudshingi
line
01-03-2015 at 3:37
hrs
220KV Chikodi-Talandagi & 220KV
Chikkodi-Mudashingi lines tripped from
Talandage and Mudshingi due to
400KV Karad line fault
GI-1
Deliberations:
KPTCL:
At 3.35 hrs., 220kV Chikkodi - Talandagi & 220kV Chikkodi - Mudashingi lines tripped from Talandage and Mudshingi due to fault on 400kV Karad line (in Maharashtra).
Subsequently around 4.15 hrs., the 220KV Belgaum-Chikkodi-I & II lines were hand tripped at 220KV Chikkodi end and 220 kV Belgaum R/S has taken KPTCL Supply from 220KV Narendra line ( Both 220KV Belgaum-Chikkodi-I & II lines GOS Opened & CB OFF at 220KV Belgaum end).
Then, Chikkodi – Mudushingi line test charged at 4.44 hrs., but tripped on DPR, zone-1, YN, 26.5 km from Mudushingi end. It was observed that Insulator got de-capped at location 232 and 238 of the line.
Remedial measures: Chikkodi – Mudushingi line charged after attending the line fault. Chikkodi – Talandage line charged as per SLDC instructions.
12 Tripping of 400kV
Neelamangala-Mysore
Line-2
01-03-2015 at 2:19
hrs & 18:01 hrs
Line tripped on operation of over
voltage protection at Nelamangala end.
Suspected faulty Y-phase CVT had
caused the tripping.
GI-2
Deliberations:
SRLDC:
On both the occasions, the line tripped due to Over Voltage, Stage-I operation at Nelamangala end and due to DT receipt at Mysore end from Nelamangala.
Suspected malfunctioning of either Over Voltage Stage 1 Relay or Y-Phase CVT. KPTCL:
Bays at Nelamangala are being maintained by PGCIL (SR-II) PGCIL (SR-II):
Over voltage relays were swapped for Stage-1 and Stage-2.
Remedial measures:
ANNEXURE-II
16 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Action has been taken to set Stage-1 (110%) relay setting to Main 1 protection REL - 521 & Stage -2 (140%) relay setting for External O/V relay.
Y-Phase CVT of Mysore Line 2 was replaced by spare one at Nelamangala.
13 Tripping of 400kV
Neelamangala-Mysore
Line-1
02-03-2015 at 23:30
hrs
Line tripped on operation of over
voltage protection at Neelamangala end.
GI-2
Deliberations:
As per TR (Trip Report) of Mysore,
Over voltage protection operated at Nelamangala end and direct trip was received at Mysore.
KPTCL:
Drop out to pick up ratio was tested recently.
The voltage was 243 kV and over voltage stage-I got operated. SRLDC:
Operation of Overvoltage protection could not be established as D.R/ E.L of Nelamangala station were not furnished.
Recommendations: PGCIL (SR-II) to check OVR operation at Nelamangala.
14 Tripping of ICT-1, 2
at Trissur substation of
KSEB
03-03-2015 at 17:02
hrs
Bus-bar protection got operated at
Trissur substation
GI-2
Deliberations:
KSEB:
On 03.03.15 at 9.02 hrs, ICT-3 tripped due to a close-in fault near Madakkathara (Trissur).
On the same day, while testing the relays meant for ICT#3, LBB protection (which was not kept disabled previously) got initiated.
As the LBB is routed through BB protection, a misplaced lead wire connection from CRM module of BB protection panel initiated a tripping signal to ICT – 1 & 2.
The relays of ICT # 1and # 2 at 400 kV Substation, Madakkathara are static and old relays. Hence no DR/EL could be furnished.
Remedial Measures: The rectification was done on 04.03.2015. Replacement of old relays with new numerical relays are under progress.
15 Tripping of
400/220kV ICT-2
and 3 at Hoody
substation of
KPTCL
3-03-2015 at
23:44 hrs
Mal-operation Oil surge relay GI-2
Deliberations:
KPTCL:
ICT#2 trip: The B-ph Transformer has been kept idle since its failure on 18.4.2014. The OLTC
Bucholtz 'B phase' (OSR) relay has malfunctioned.
ANNEXURE-II
17 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Remedial measures: 1. The control cables of B-Ph have been checked up and insulation tape put to each core. 2. Further the auxiliary relays of B-ph Transformer have been taken out to avoid any malfunctioning.
ICT#3 trip: Due to heavy rain, moisture had got collected near the trip terminals of 'Y' phase OSR
relay. ICT-3 also got tripped due to operation of OSR relay of Y-phase transformer. Remedial Measures:
1. Moisture contents cleaned and dried from trip terminals of 'Y' phase & terminals have been tightened. Utmost care taken to prevent further entry of moisture.
16 Tripping of UNIT- 3
& 5 at Jindal power
station
08-03-2015
19:41hrs
Units tripped due to tripping of SUT. GI-2
Deliberations:
Triggering incident:
B-Phase LA flashover occurred at Lingapur end on Lingapur – Munirabad-PG 220 kV line-2
JSWEL:
As per JSWEL SPS, whenever the voltage at 220 kV bus drops below 78 % of the normal phase voltage (99 kV) AND the current flow on 220 kV lines exceeds 1000 A, all 220 kV line CB’s would trip with a time delay of 200 msec.
However, in the instant case, due to the time lag in the simultaneous fulfillment of the above voltage and current conditions, SPS operated with a time delay of 500 msec and tripped the two Lingapur bound 220 KV lines.
The 400 kV Bus Coupler tripped on Over load with a time delay of 500 msec.
Munirabad
Lingapur
LA failed
Steel Plant
2
1
SPS trip:
78% V & > 1000 A
4
3
2 5
6
1
BTPS
Guttur
300 MW
130 MW
130 MW
1
b/u trip
ICT
400 kV 220 kV
over speed
2
2
3
4
5
aux. trip
JSWEL
Z-2 sense
O/L trip
ANNEXURE-II
18 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
The two 400/ 220 kV ICT tripped on back-up protection with a time delay of 900 msec.
On account of this, Units 3 & 5 & 1 tripped on Over Speed due to lack of availability of the lines for power evacuation.
After half-an-hour or so, the Unit-4 also got tripped due to problem in its instrument air compressor.
Auxiliaries are fed from 220 kV side.
The Unit-6 did not trip during the incident.
400 kV Bus coupler settings: 149% of ICT current for 0.5 sec.; 130% for 5 sec; 120% for 10 sec.
Suggested for OR-ing of the conditions in the existing SPS to avoid delayed operation.
SRLDC:
As the OR-ing of the voltage and current conditions in the SPS could lead to frequent trippings, better not to meddle with the existing SPS. Instead, DEF feature in the numerical relay for the 220 kV Jindal – Lingapur lines at Jindal end should be enabled as suggested by KPTCL.
Recommendations: JSWEL to enable DEF feature in the numerical relay for the 220 kV Jindal – Lingapur lines
at Jindal end.
17 Tripping of ICT-1 at
Munirabad
08-03-2015
19:41hrs
ICT -I got tripped on operation of
220KV E/F
Deliberations:
B-Phase LA flashover occurred at Lingapur end on Lingapur – Munirabad-PG 220 kV line-2
As a result, Distance protection at Lingapur end cleared the fault in zone-1. Fault was being fed from Munirabad (PG end) of Lingapur line-2 as the distance relay
sensed the fault in zone-3. ICT-1 at Munirabad-PG tripped on 220 kV DEF protection. As the Kalyani feeder is being fed radially (10-20 MW load), Munirabad-PG – Kalyani
220 kV S/C line tripped on operation of distance protection at Munirabad-PG end.
2
1
Munirabad
Lingapur
Jindal
LA failed
Kalyani Steel
1
2
Distance
protn.
DEF
Z-1 trip
SPS trip
Z-3 trip 220 kV
400 kV
ANNEXURE-II
19 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Unit-3 & Unit-5 at JSWEL also tripped due to SPS operation. SRLDC:
Reason for sensing the fault in Zone-3 at 220kV Munirabad (PG end) of Lingapur line-2.
Both ICT’s at Munirabad-PG would have sensed the fault. However ICT-1 only tripped.
PGCIL (SR-I):
There was mal-operation of distance relay; OEM has been approached.
Kalyani feeder is being maintained by PGCIL.
Recommendations: PGCIL (SR-II) to furnish the reasons for mal-operation of distance relay & non-operation of
220 kV DEF for ICT-2 at Munirabad-PG, along with the remedial measures taken to PCSC forum.
18 Multiple tripping at
Raichur thermal
power station of
KPCL
09-03-2015 at
06:36 hrs
400kV Raichur TPS-Raichur(PG) line-
1&2, 400kV Raichur-Mahboobnagar,
Unit#7 and ICT-2 at RTPS tripped
during the incident. B phase to earth
fault had occurred in 400kV Raichur
TPS-Raichur line-1
GI-2
Deliberations:
As per PMU plots, there occurred two faults on 440 kV RTPS – Raichur-PG line 1.
The first fault occurred at 06:36:18.520 hrs (B-ph to earth fault) and got cleared in 120ms. The second fault occurred 13 sec after the occurrence of first fault involving R, Y & B -phase at 6:36:31.480 hrs, and got cleared in 360 ms
As per TR of Raichur (PG), during the first fault A/R operated successfully.
During the second fault, there was no A/R attempt, and 3-ph trip was given (Fault Current-15KA). Reason for this was stated to be decapping of insulators at RTPS end. Due to this, The 400 kV RTPS – Raichur(PG) line 1 tripped at RTPS end in Zone-1 with SOTF.
RTPS
1
Raichur(PG)
3-ph trip
2
Veltoor (Mehabubnagar)
Z-2 trip
(SOTF) Z-4 start
G7
Distance
protection
(Bn) REF of GT
trip: 6:36:31 hrs
restore: 8:02 hrs
trip: 6:36:23 hrs
restore: 8:18 hrs
trip: 6:36:18 hrs
restore: 8:18 hrs
trip: 6:36:31 hrs
trip: 6:36:36 hrs
restore: 8:02 hrs
RTPS
1
Raichur(PG)
Z-1 trip
(SOTF)
A/R
2
Veltoor (Mehabubnagar)
G7
ANNEXURE-II
20 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
The 400 kV Raichur – Raichur(PG) line 2 tripped at RTPS end in Zone-2 with SOTF; no trip at Raichur(PG) end and only Zone-4 start was there.
U-7 tripped on GT Restricted Earth Fault at RTPS. RTPS-Mehboobnagar (Veltoor) 400 kV S/C line tripped at Veltoor end due to
suspected mal-operation of distance protection.
Now POR distance protection scheme is in place at both ends (RTPS and Raichur(PG)) after PSAG meeting at Raichur.
KPCL informed that ICT#2 did not trip during the incident. Observations:
DR/TR of Mehbubnagar (Veltoor) have not been furnished to ascertain the cause of tripping at Mehabubnagar.
Time synchronization of D.R’s at both RTPS and Raichur(PG) with GPS for 400kV RTPS – Raichur(PG) lines – 1& 2 needs to be checked, as there seemed to be a time difference of 5 sec. between PMU plots and the DR’s at both ends.
PGCIL:
With RTPS settings with CB’s in OPEN condition, a simulation was done in the lab for testing the functionality of distance relays and found them to be operating SOTF. To confirm this, it has been planned to test the breakers by availing shutdown of the lines on 28.03.2015.
SRLDC:
After tripping, the problem should have been rectified on that very day itself by taking shut down if required. SRLDC object (oppose) this type of operation.
For short lines such as RTPS – Raichur (PG) 400 kV D/C line, Kurnool – Kurnool(PG) 400 kV D/C line, Optic Fibre based line differential protection could be used.
Recommendations:
KPCL to review REF setting (DMT or IDMTL) for unit-7 by first week of April, 2015 and inform the same to PCSC forum.
TSTRANSCO to furnish Mehaboobnagar’s DR and EL and the reasons for distance relay operation at their end within a week’s time.
PGCIL (SR-I) to rectify the issues relating to A/R operation, relay reach (Z2), reverse reach (Z4) and SOTF auxiliary contacts within a week’s time, and submit the actions taken to PCSC forum.
19 Tripping of 220kV
Kaiga-Kodassalli
line, Unit-1, 2&3 at
Kaiga PowerStation
11-03-2015 at
21:59 hrs
B-phase CT failed in 220kV Kaiga-
Kodasalli line. Bus bar protection of
220kV Bus-2 got operated
GI-1
SLD: Kaiga-1, 2, 3, 4
ANNEXURE-II
21 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Deliberations:
B-ph CT (Current Transformer) failed at Kaiga on Kaiga – Kodasalli S/C 220 kV line. Due
to this,
Kaiga-Kodasalli line tripped on zone-1 distance protection at Koadalli end only. The fault distance recorded at Kaiga end was 203.1 meter in the numerical relay. At 220kV Kaiga switchyard, Main Bus- II differential protection operated tripping Units
1, 2 & 3. KGS:
The Kaiga Generating Station 220 kV switchyard consists of two 220 kV power evacuation lines and two 220 kV Buses Bus-I and Bus-II and the Bus coupler is kept closed. The 400 kV switchyard has four 400 kV power evacuation lines and two 400 kV buses. The 220 and 400 kV buses are interconnected through two ICTs, ICT-1 and ICT-2.
On 11.03.2015, KGS-1 & 2 were operating at 100% FP. 220kV Buses I & II were in service. 220 kV line-I, ICT-2, GT-2, SUT-I and SUT-4 were connected to Main Bus-I and 220 kV line-2, ICT-I, GT-I, SUT-2 and SUT-3 were connected to Main Bus-II. The Bus coupler was in closed condition.
At 21:59: 15 hrs, the B phase CT (current transformer) of 220 kV line 2 (Kaiga-Kodasalli) connected to Main Bus-II failed and caused 220 kV Bus-II Bus bar differential protection to actuate. This resulted in tripping of all breakers connected to 220 kV Bus II including Bus coupler breaker.
Narendra2
Busbar
differential trip
Kadra
G2
ICT2 GT2
SUT1 SUT4
Kodasalli
G1
ICT1 GT1
SUT2 SUT3
B/C
220 kV Bus-I 220 kV Bus-II
Z-1 trip
CT
failure
GT3
G4
Guttur2
Bus-I
Narendra1
G3
GT4 Guttur1
400 kV
Bus-II
Bus Reactor
KGS-2 trip on
process
parameter
KGS-3 trip on
process parameter
due to SUT3 trip
KGS-1 on house
load operation
ANNEXURE-II
22 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Upon tripping of GT breaker of KGS-1 , the Unit survived on house load with half of the station loads being fed from UAT and the other half from SUT-1. Later GT-1 was synchronized back to the grid with 220 kV Bus-I at 23: 19 hrs of 11.03.15.
In KGS-2, the 6.6 kV auto transfer took place as per design. But during the transient due to the voltage dip in the station aux. 6.6 kV Bus, some of the auxiliary loads tripped leading to reactor trip on process parameter as per design.
In KGS-3, SUT-3 tripped on 220 kV bus-II differential protection actuation and Auto Transfer got blocked due to excessive voltage dip on station auxiliary 6.6 kV buses as the fault location was very nearby. This caused tripping of some of station auxiliary loads on bus under voltage leading to reactor trip on process parameter as per design.
In both the cases, 6.6 kV voltage came down to 1 kV and the current drawal went up to 7 times which resulted in tripping of the auxiliaries instantaneously.
Remedial measures: The failed CT of Kaiga - Kodasalli 220 kV line was replaced with new CT and line has
been taken back into service at 18:14 hrs of 15.03.15. The reason for CT failure is being investigated. Lines are in service since 1993; CTs and CVTs have been planned to be replaced.
SRLDC:
The fact that a 100 msec. fault could not have been sustained by the auxiliaries calls for changing their settings.
Recommendations: KGS to furnish the reasons for CT failure to PCSC forum.
20 Tripping of ICT-2
at Mahboobnagar
09-03-2015 at
7:57 hrs
Tripped on operation of restricted earth
fault (REF) relay while charging 400kV
Raichur-Veltoor feeder
GI-1
Deliberations:
SRLDC:
As per FIR, ICT-2 tripped on operation of REF protection while charging 400kV RTPS -Mehboobnagar line. However, no fault was observed from synchrophasor data.
The station shall be kept under observation. TSTRANSCO:
Moisture ingressed into the neutral CT compartment and REF got activated.
ICT-2 is using 7 CTs (HV, LV and neutral) for REF protection; REF relay setting is 0.2 A Remedial measures:
The accumulated water in terminal box of the Neutral CT drained out and made
vermin and water proof.
SRPC:
No DR/TR furnished, which may be uploaded/ furnished.
ANNEXURE-II
23 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
21 Tripping of 400
kV Dichipally –
Ramagundam and
Unit-6 at
Ramagundam
09-03-2015 at
00:56 hrs
Line tripped on B phase to earth fault.
Unit-6 tripped on operation of GT
differential protection
GI-2
Deliberations:
NTPC: Tripping of Dichipally-Ramagundam STPS 400 kV S/C line:
This line tripped on B phase to Earth fault on zone 1 at RSTS end and Zone-2 at Dichipally end.
The fault current was observed to be apprx. 30 kilo amp and fault distance of 34. 5 kilo metres from Ramagundam.
A/R is not active on this line.
Remedial measures: Line patrolling was done by TSTRANSCO. No visible fault observed. Line taken into
service. Tripping of Unit – 6 at RSTPS:
Unit-6 tripped on GT differential protection despite no fault in the GT.
The cause could be due to non-enabling of zero sequence compensation (ZSC) feature in the numerical relay, which could mal-operate the unit protection for through fault.
Remedial measures: ZSC was enabled in the relay meant for protecting Unit-6 (REG -670)
Recommendations:
NTPC, Ramagundam to enable A/R feature on Dichipally – RSTPS 400 kV S/C line in coordination with TSTRANSCO.
NTPC to enable ZSC feature in relays meant for protecting the other generating units.
22 Tripping of
HVDC pole-1&2
at Gazuwaka and
400kV 400kV
Jeypore Gajuwaka
line -1
14-03-2015 at
17:12 hrs
HVDC Pole-1 at Gazuwaka tripped due to
tripping of filter banks and Pole-2 tripped
due to operation of differential protection.
400kV Jeypore-Gazuwaka line-1 tripped
on over-voltage from Gazuwaka end.
GI-2
ANNEXURE-II
24 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Deliberations:
As per FIR of HVDC, Gazuwaka, R-phase to earth fault (Distance from Gajuwaka - 146.6 KM;
From Jeypore end 43.5 KM) had occurred at 17:12:33 hrs in 400kV Jeypore-Gazuwaka line-2. During a single phase fault, at Jeypore end there is provision for single phase auto reclose and at Gajuwaka there is provision for 3 phase auto reclose. The line successfully auto reclosed from both the ends.
Some 750ms after the fault in 400kV Jeypore-Gazuwaka line-2, L.A failure occurred in East side filter banks at Gakuwaka and this led to operation of instantaneous over current relay and tripping of East side filter banks. The tripping of Filter banks led to blocking of Pole-1 at Gazuwaka.
800ms after occurrence of fault in line-2, 400kV Jeypore-Gazuwaka line-1 tripped on operation of Over voltage, Stage II protection at Gazuwaka end (i.e. during auto reclose period of Line-2). However, line-1 did not trip from Jeypore end as direct trip was not received there.
Pole-2 at Gazuwaka tripped on operation of Converter Transformer differential current B-phase trip.
After tripping of HVDC pole-1&2, 400kV Jeypore-Gazuwaka Line-1 was holding from Jeypore end and in tripped condition at Gazuwaka end. Breakers of 400kV Jeypore-Gazuwaka Line-2 was in closed condition from both ends. Line-1 was hand tripped from Jeypore end to reduce the over voltage condition.
East Bus
P1
East
Filters
P2
P2
Filters
South
Filters
400 kV
AC S/S
Jeypore
2 1
South Bus
Pole-2 trip:
converter trf. diff.
protn. Line-1 trip:
O/V stg-2
East filters trip:
inst. O/C protn.
due to LA failure
Pole-1 block:
due to
non-availability
of filter bus
1 2 3
4
Gajuwaka HVDC B2B
ANNEXURE-II
25 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
PGCIL (SR-I):
Remedial measures: o PLCC is not working properly. PLCC panels are being retrofitted with ETL. LOA
already placed, and the work may get completed in 3 months. o Pole-2 tripping due to differential protection operation has been referred to
OEM (M/s ABB).
SRLDC:
If PLCC is not working, the line should not be kept into service in the first place.
Recently, ILFS-NLC 1 Exp. line was also charged without PLCC.
Any problem on PLCC is to be reported to SRLDC.
Over voltage observed in D.R of Jeypore – Gajuwaka line 1 is less than Stage-1 setting.
DR-EL time sync. to be checked at Gajuwaka.
Recommendations: PGCIL (SR-I) to furnish the reasons for Converter Transformer differential protection
operation for Pole-2 along with the remedial measures taken.
23 Tripping of HVDC
Bhadravathi Pole-1
18-03-2015 at
13:55 hrs
Pole tripped due to failure of auxiliary
supply
GI-2
Deliberations: As per TR of HVDC, Bhadrawati:
On 18.03.2015, the auxiliary supply of both pole-1 & 2 was being fed by 33KV WARORA feeder as MIDC feeder was already out.
At 13:53Hrs, WARORA Aux Supply tripped, due to which main pumps of VCC1 & VCC2 started running at half-speed.
DG-1 & 2 came into service.
Now the auxiliary supply of both pole-1 & 2 were being fed by DG-1 & DG-2 and both the pumps of VCC1 & VCC2 were to run at full-speed now.
However, the main pump of VCC1, Pump-1, which was at half-speed before DG came into service did not attain full speed and Pole-1 tripped on “VCC1.MAIN CIRCUIT FULL FLOW - V-LOW” alarm.
The control circuit of VCC1 Main pump has been checked for not attaining full speed. The control circuitry was found OKAY. No abnormality observed in the control circuit. This leads to assumption of malicious operations of Pump-1 which needs further investigation during Pole Shut down.
It is observed that the disturbance/frequent tripping in the Auxiliary power supply caused the mal-operation of control logic circuit (Memory logic) of valve cooling system which resulted in failure/stopping of Main pump and tripping of the pole consequently.
The 33kV aux supply taken from MSEDCL is unreliable and not stable. Several trippings have occurred due to disturbance in aux supply and the problem is persisting.
It is expected that such disturbances may get avoided once the 315 MVA,400/220/33 kV,3Phase ICT gets loaded. The ICT has been ideally charged on 17.03.2015 and would be loaded once clearance from MSETCL is obtained.
SRPC:
PGICL (SR-I) has not yet submitted the compliance report on PSAG-11 recommendations. SRLDC:
ANNEXURE-II
26 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
MS (SRPC) to MS (WRPC) letter could be written for expediting the aux. power supply problem issue.
Recommendations:
PGCIL (SR-I) to submit the compliance report on PSAG-11 recommendations to PCSC forum.
24 400 kV NCTPS II-
VALLUR 1
21-Mar-15 at
23.33 hrs.
Tripped while opening 400kV
VLR-NCTP 2 on broken
conductor protection
GI-2
25 400 kV NCTPS II-
VALLUR 1
20-Mar-15 at
13.02 hrs.
DISTANCE PROTECTION GI-2
26 400 kV NCTPS II -
VALLUR 2
19-Mar-15 at
19.40 hrs.
Tripped on operation of broken
conductor alarm at NCTPS
GI-2
Deliberations:
On all the three occasions, the 400 kV NCTPS – NTECL (Vallur) lines 1/ 2 tripped due to broken conductor protection at NCTPS, Stage II end; NTECL (Vallur) end tripped due to receipt of DT from NCTPS, Stage II.
NTECL, Vallur:
Heavy load/current unbalance has been observed in Vallur- NCTPS line 1 and 2 which has led to tripping of lines on Broken conductor protection many times from NCTPS end and once from Vallur end.
TANTRANSCO may analyze the reason for the unbalance in the lines and take necessary corrective action.
TANTRANSCO:
As part of remedial measures, broken conductor protection trip has been disabled at NCTPS –II.
At NCTPS the line protection setup is: o Main-1: line differential (Micomp); Main-2: line differential (RAD). o Different pairs of fibres are used for Main-1 & 2 relays. o Distance protection is used as back up protection. o Back up O/C and E/F are also there.
KPTCL:
220 kV cables in Bangalore are also using line differential protection.
PGCIL (SR-II):
400 kV trip is disabled for broken conductor in SR-2 and only alarm is enabled.
ANNEXURE-II
27 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
27 400 kV NCTPS II- VALLUR 1 17-Mar-15 at
03.00 hrs.
Y-N FAULT GI-2
Deliberations: Line tripped on Y phase differential protection @ 3:00hrs. due to tracking of insulators on
TANTRANSCO tower at NTECL.
TANTRANSCO:
Distance between NTECL and NCTPS is 3.35 km; the lines have been cleaned; 6 towers have been scanned from Vallur end; hot line washing has also been done.
28 400 kV NCTPS II - VALLUR 1 11-Mar-15 at
17.03 hrs.
TRIPPED WHILE CHECKING BUS
BAR DIFFERETIAL PROTECTION
GI-2
Deliberations:
Line tripped at NTECL on R phase differential protection @ 17:03 hrs during testing of bus-bar protection relay; line was holding at NCTPS-II end. NTECL, Vallur:
As part of remedial measure, an unwanted logic in line protection relay, which caused the tripping
while testing bus-bar protection relay, was removed.
29 Tripping of 220kV Neyveli-
Villanur
18-03-2015 at
11:57 hrs
R-N fault in Line. Fault observed
for 400ms in Neyveli end D.R
GI-1
Deliberations:
As per TR of Villianur: R-Phase earth fault occurred on the 230KV Neyveli-Villianur line; MICOM P442 Main-I Numerical Distance Protection relay gave A/R single shot closing pulse and closed the tripped R-phase pole column of the 230KV Neyveli Breaker at Villianur Auto Sub-Station end. However, owing to persisting fault, the breaker tripped on receipt of 3-phase trip signal from the distance relay. As per DR of NLC 2: The R-N fault was lasting upto 400 msec only from the time the first shot of A/R operated. (This means the fault got cleared in the A/R open dead time of 1 sec.) Remedial Measures taken at Villianur by PED:
Panel replacement has been done. SRPC:
Reasons for above discrepancy may be analysed by Villanur.
DR not uploaded by Villianur.
FIR uploaded by NLC 2 was not in order; TR not uploaded.
ANNEXURE-II
28 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
III Tripping events due to PLCC Mal-operation:
Sl. No.
Element Date & Time
Reason PCSC Deliberations
1 Tripping of 400kV
Ghanapur -
Mamidapalli line
18-02-2015
at 12:12 hrs Line tripped from
Mamidapalli end due
to direct trip receive
from Ghanapur
PGCIL: even as on today the
alarm is persisting.
SRLDC: The line is not to be
charged under non-cleared
alarm condition.
2 Tripping of 400 kV
Khammam-Kalpakka
line-1
18-02-2015
at 12:58 hrs Line tripped at
Kalpakka end only due
to direct trip receive
and was holding from
Khammam
PGCIL (SR-I): There was a
problem with Main-1 relay. It was
reset, and found to be working
normally.
3 Tripping of 400kV
Malkaram-
Hyderabad line
20-02-2015
at 10:37 hrs Line tripped at
Malkaram end only
due to direct trip
receive and was
holding from
Hyderabad end.
PGCIL (SR-I): At Ghanapur
(Hyderabad), due to NTMC works
in progress, a spurious signal got
extended as DT to Malkaram.
4 Tripping of 400kV
Munirabad-Guttur
line
21-02-2015
at 00:26 hrs Line tripped at
Munirabad
(Guddadalli ) end only
due to direct trip
receive and was
holding from Guttur.
End to end testing has to be carried
out.
5 Tripping of 400kV
Hiryur-Neelamangala
line-2
27-02-2015
at 17:19 hrs Line tripped at
Neelamangala end
only and was holding
from Hiryur.
End to end test has already been
carried out.
6 Tripping of 400kV
NLC EXP-IL&FS
line
28-02-2015
at 19:17 hrs Line tripped from
NLC –I expansion end
only due to direct trip
receive and line was
holding from IL&FS.
The faulty card has been replaced
at IL&FS; Tested at NLC end
also.
7 Tripping of 400kV
Narendra-Guttur 11-03-2015
at 17:16 hrs Line tripped at
Narendra end only due
to DT receive.
Narendra-Davanagere line -1
tripped at Narendra end only, and
was holding from Guttur
(Davangere) end.
End to end testing has to be
done.
8 400 kV Tiruvelam -
Kalivandapatu 1 11-03-2015
at 19:32 hrs Line tripped at
kalivaldapattu end
only due to DT
receive.
Line tripped due to mal-operation
of DTPC (Digital tele-protection
coupler) at Kalvindapattu end only.
The line was holding from
ANNEXURE-II
29 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
Tiruvalam end.
9 Tripping of 400kV
Thiruvelam-
Kalivandapattu line-1
17-03-2015
at 18:05 hrs Line tripped at
Kalivandapattu end
only
Line tripped at Kalvindapattu end
only, and was holding from
Tiruvalam end.
For all the above cases of PLCC mal-operation, the following shall be carried out by the concerned
Constituents in co-ordination: Healthiness of PLCC system components (hardware and software) at both ends shall be checked
and faulty components shall be repaired/replaced. End-to-end communication for DT/ permissive & other signals may be ensured by testing at both
the ends.
IV. Tripping events due to failure/ non-operation of Auto-Reclose (A/R) during
Transient fault:
S.No Element Date &
Time Reason PCSC Deliberations
1 Tripping of 400kV
NTPL-Tuticorin P.S
line
23-02-2015
at 4:42 hrs
and
24-02-2015
at 4:30 hrs
Transient fault in
B-phase and line
auto-reclosed from
Tuticorin P.S end.
Line failed to
reclose from NTPL
end
On both the occasions, line auto-
reclosed from Tuticorin Pooling
Station end, but failed at NTPL
end.
A/R setting at NTPL end has
been revised to 1 sec.
PGCIL (SR-II): 1. Line inspection was under
progress. 2. Tower No 29 from NTPL end
B-Phase toward s NTPL end PLR
insulator was replaced by CLR
insulators by PGCIL and R & B
Phase insulators were cleaned. SRPC: A/R scheme shall be tested
at NTPL in coordination with
Tuticorin PS.
2 Tripping of 400kV
Jeypore-Gazuwaka
line-1
28-02-2015
at 00:19 hrs R-phase to earth
fault had occurred
in line. Line auto
reclosed at Jeypore
end and failed to
reclose at
Gazuwaka.
Line auto reclosed at Jeypore end
and failed to reclose at Gazuwaka.
Relay testing is to be done.
SRPC: Remedial measures taken
may be furnished by PGCIL (SR-I)
to PCSC forum.
ANNEXURE-II
30 Grid Occurrences of 42nd
PCSC Meeting held on 26-03-2015
3 Tripping of 400kV
Coastal-NTPL line
02-03-2015
at 3:51 hrs
Line tripped on a
B-phase to earth
fault. Line auto-
reclosed from
coastal end and
tripped at NTPL
end.
A/R setting at NTPL end has
been revised to 1 sec.
SRPC: A/R scheme shall be tested
at NTPL in coordination with
CEPL.
4 Tripping of 220kV
Ambewadi-Ponda
line-1
11-03-2015
at 11:10
Line did not auto
reclose
SRPC: A/R scheme to be enabled
for this inter-state line.
5 Tripping of 220kV
Ambewadi-Ponda
line-2
11-03-2015
at 13:32
Line did not auto
reclose
SRPC: A/R scheme to be enabled
for this inter-state line.
6 Tripping of 220kV
Yerandahalli-Hosur
line
18-03-2015
at 13:12 hrs
B-N fault. Line did
not auto-reclose
SRPC: A/R scheme to be enabled
for this inter-state line.
X---------------------------------------------------------X--------------------------------------------------------X
ANNEXURE-II
Meeting
No /
Index
Details
of Event
Date Reason PCSC Recommendations Utility
Responsibl
e for
Status of Recommendations
as on 16.04.2015
Remarks
39/III/1 Tripping
of 400kv
VTPS-
Satenapal
li line-
1 &2
10, 11, 13,
14,15 Dec
2014
voltage.
grading in over voltage protection
needs to be verified.
PCSC forum recommended APTRANSCO to check up the
drop off to pick up ratio of the Overvoltage relay and correct
it (if needed).
APTRANS
CO/
APGENCO
APTRANSCO informed vide their e-mail
dated 27.02.15 that the issue pertains to
APGENCO.
Pending
40/IV/2 400 kV
HYDER
ABAD -
KURNO
OL line
07-01-2015
at 6:17 hrs
Line tripped on Rphase to earth fault.
A/R lock out
observed in E.L of Hyderabad end
APTRANSCO was requested to check up the A/R feature at
both the ends and submit the remedial measures to the PCSC
forum.
APTRANS
CO
Yet to be informed Pending
41/II/2 Tripping
of 400kV
Srisailam-
Mamidap
alli-2 line
and
400kV
Srisailam-
Satenapal
li-1 line
23-01-2015
at 16:10 hrs
Bus-2 at Srisailam became dead while
converting Srisailam generator to
condenser mode. Direct trip was
received at Mamidapalli and
Satenapalli end.
furnish the reasons for BBP operation at
Srisailam LLB and the remedial action taken to PCSC forum.
TSGENCO Yet to be informed Pending
Pending Implementation of PCSC Recommendations (30th to 41st)
Andhra Pradesh
Telangana
Karnataka
ANNEXURE-III
1 PCSC-42
30/I/A RTPS
Tripping
incidents
and the
Spl
meeting
held at
RTPS on
13th and
14th
March
2014
Mar-14 Spl meeting held at RTPS on 13th and
14th
March 2014
The PCSC forum recommended for replacement of existing
electromechanical relays with Numerical relays.
KPCL 1. e- Tender folated for the retrofit of
existing static relays with Numerical version
for lines M.nagar,M.bad,ICT-1 & 2 -
Technical Bid opened & price bid yet to be
opened.
2. Retrofit of existing bus bar (CAG-34)
with numerical version -Budgetetory offers
obtained and is under process.
3. Order placed on M/s Siemens to replace
relays. The work will be Completed by May
- 2015.
Pending
33/II/3 400kV
Hiriyur-
BTPS
line-2
22-05-14 &
23/05/2014
B phase to ground fault had occurred in
line and line auto reclosed at Hiriyur
end but failed to reclose at BTPS end.
The PCSC forum requested KPCL to enable the A/R feature at
RTPS end before next PCSC meeting (i.e. 31st July, 2014.
KPCL 1. A/R for 220kV lines enabled already.
2. Shtu down of lines availed to commission
the auto reclosing schme fro 400 kV line at
BTPS.
3. A/R shall be enabled in next shutdown
Pending
34/III/1 400kV
Raichur-
BTPS
line
26-06-2014 Transient fault in R-phase.
Line did not auto reclose
A/R at BTPS end to be made operational within one month KPCL 1. A/R for 220kV lines enabled already.
2. Shut down of lines availed to commission
the auto reclosing schme fro 400 kV line at
BTPS.
3. A/R shall be enabled in next shutdown
Pending
38/GD/3
.5
GD-1 at
Kadra
and
Kodasalli
hydro
power
station
13-11-2014
at 19:31hrs
A fault had occurred in 220 kV Kadra
and
Kodasalli. As A result, de-energization
of
220kV bus occurred at Kadra and
Kodasalli.
1. The PCSC forum requested KPCL to speed up the
installation of Numerical Distance Protection relay in Kadra
–Kaiga and Kodasalli –Kaiga.
2. The PCSC forum requested KPCL to submit the
implementation status of PSAG-10 recommendations within a
week’s time.
KPCL All the recommendations of PSAG - 10 are
completed except the following pending
issue:
i)e-NIT floated on 28.07.2014 for
procurement of Numerical distance relays &
GPS. Bid evaluation is under progress. The
work will be completed by December -
2015. Hower, as per the recommendations
of PSAG, Relays were temporarily
rearranged, replaced and wired up. testing &
commissioning shall be completed with the
assistance of KPTCL by March 1st week ,
2015.
Pending
ANNEXURE-III
2 PCSC-42
34/I/6 400/220
kV ICT-1
& 2 at
MUNIR
ABAD
16-07-2014 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.
4. Correct DR shall be submitted to the SRLDC for trip analysis.
KPTCL Management approval is obtained for taking
up the work of providing bus bar protection
to 220kV buses at Guddadahally
(Munirabad) Sub Station along with
replacement of 3 core/age old CTs of 220kV
bays belong to KPTCL.
Under implementation
Mail recieved on 25-03-2015 (KPTCL):
1. KPTCL has taken action to provide bus
bar protection to 220kV buses.
2. Over current relay Settings of ICTs to be
reviewed by PGCIL.
Pending
38/GD/3
.1
GD-1 at
Mahaling
apura
Substatio
n of
KPTCL
25-10-2014 Fault had occurred in 220kV
Mahalingapura-Narendra line-2. Due to
the
failure of relay operation at
Mahalingapura,
breakers at remote end tripped which
resulted in bus dead condition.
1. PCSC forum recommended KPTCL to replace the old static
distance protection relays with numerical relays.
2. PCSC forum also requested KPTCL to provide a broken
conductor alarm indication in Control Room.
3. Standing instruction needed to be given to the all substation
personnel for not changing the relay settings without approval of
RT/MRT wing.
KPTCL Mail received on 25-03-2015 (KPTCL):
1.Existing Back up relays will be replaced
by numerical type distance
relays.Procurement is in tendering stage.
2. Alarm for Broken conductor is in service.
3. Clear instructions have been given to
station staff.
Pending
38/GD/3
.2
GD-1 at
Guttur
Substatio
n of
KPTCL
05-11-2014
at 11:42 hrs
Circuit breaker of 400kV Guttur-
Hiriyur
line-1 failed at Guttur end while
availing
shutdown for replacement of CVT. The
failure of breaker caused bus fault at
Guttur.
KPTCL was requested to expedite the early implementation of
pending recommendations of:
1. Protection Audit (Phase-I & Phase-II)
2. PSAG-4, PSAG-5, and PSAG-8
KPTCL Mail received on 25-03-2015 (KPTCL):
Replacement of failed breaker of Hiriyur-1
line, 400kV BC and TBC is taken up at
Guttur. Work is entrusted to M/s
Alstom.Complaince will be furnished to
SRPC upon completion of these works.
Pending
ANNEXURE-III
3 PCSC-42
39/I/5 Tripping
of
400/220k
V
ICT-2 at
Hoody
substatio
n of
KPTCL
01-12-2014 Suspected mal-operation of 220kV side
Rphase
over current relay
1. PCSC forum recommended KPTCL to replace the relay with
a different make.
2. KPTCL was also requested to train the O&M personnel
adequately before performing any maintenance works to avoid
such unwanted trippings.
KPTCL Mail received on 25-03-2015 (KPTCL):
C&R panels of 500MVA ICT 1&2 will be
replaced under scheduled R&M works.
O&M personnel are instructed to take
sufficient care in order to avoid unwarrented
trippings.
Pending
40/I/1 GD-1 at
220kV
Ambewa
di Station
of
KPTCL
22-12-2014
at 21:22 hrs
Triggering incident was B-phase to
earth fault in 220kV Ambewadi-
Nagzari line-1. B-pole of breaker did
not open at Ambewadi end. LBB
protection not available at Ambewadi
end. All elements tripped on Zone-2
from remote ends.
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 check up the ICTs protection system for
finding the cause of not tripping for the line fault (through fault)
and submit the remedial measures.
3. KPTCL shall provide the details of the tripping of Supa hydro
station connected downstream from 110 kV bus.
KPTCL Yet to be informed Pending
40/IV/1 220kV
Sedam-
Tandur
line
20-12-2014
at 22:20 hrs
Line tripped on Yphase to earth fault
from both the ends
KPTCL was requested to explore the possibility of providing
A/R feature to this line and submit the remedial measures to the
PCSC forum.
KPTCL Yet to be informed Pending
41/I/1 GD-1 at
220kV
Kadra
power
Station of
KPCL
16-02-2015
at 12:56 hrs
Triggering incident was B-phase to
earth fault had occurred in 220kV
Kadra-Kodasalli line. Line tripped from
Kodasalli end only. 220kV Kaiga-
Kadra tripped in Zone-3 from Kaiga
end. Tripping of evacuating lines
caused bus shut down at Kadra hydro
station.
1. KPCL to make functional the Main2 (EPAC) relay with
the help of KPTCL at the earliest.
2. KPCL to investigate the reason for DC fuse fail during
transient fault in 220kV Kadra-Kodasalli line including the
testing/ checking of DC supply cables, breaker control cables,
and trip coils.
3. KPCL to ensure supply for Main-1& Main-2 protections,
Trip Coils (TC1, TC2) from separate battery banks.
KPCL Yet to be informed Pending
ANNEXURE-III
4 PCSC-42
41/I/3 Complete
outage of
Nagjheri
Hydro
power
station of
KPCL
(GD-1)
22-02-2015
at 11:09 hrs
During de-synchronization of Unit-3,
the Y-pole of the CB did not open (was
locked-out). This caused LBB
protection to operate resulting in
tripping of the Bus and all connected
220kV lines and running units at
Nagjheri power station.
1. KPCL to investigate the cause of Y-pole breaker lock-out of
Unit-3, and take suitable remedial measures within a week’s time
2. KPCL to furnish what caused LBB initiation and furnish
LBB Scheme details to PCSC forum
3. KPCL to furnish detailed tripping report (with DR & EL)
of the incident
KPCL Yet to be informed Pending
41/I/4 Complete
outage at
220kV
Sedam
Substatio
n of
KPTCL
(GD-1)
27-01-2015
at 8.00 hrs
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.
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.
KPTCL Yet to be informed Pending
41/II/11 Tripping
of 400kV
BTPS -
Hiriyur
line-2
13-02-2015
at 17:07hrs
Line tripped at BTPS end only. furnish remedial measures taken to prevent
recurrence of PLCC mal-operation at BTPS.
KPCL Yet to be informed Pending
36/II/9 400kV
Arasur-
Mettur
Line I
29-09-2014 Mettur S/s to Enable A/R Scheme. TANTRA
NSCO
1. During the 38th PCSC meeting,
TANTRANSCO informed that the Auto
Reclosing facility would be enabled within
15 days.
2 A/R scheme will be implemented after the
commissioning of 400 kV Thiruvalam Line-
I & II.
Pending
Tamil Nadu
ANNEXURE-III
5 PCSC-42
37/II/3 400kV
Mettur-
Arasur
line-1
29-09-2014 Line tripped due to Y-Phase to earth
fault.
Line did not auto reclose as Auto
reclose scheme is kept in non-auto
mode.
A/R scheme to be enabled. TANTRA
NSCO
1. During the 38th PCSC meeting,
TANTRANSCO informed that the Auto
Reclosing facility would be enabled within
15 days.
2. A/R scheme will be implemented after
the commissioning of 400 kV Thiruvalam
Line-I & II.
Pending
38/II/3 Tripping
of 400kV
Mettur-
Arasur
line-2
22-10-2014 Line tripped on Rphase
to earth fault.
non-auto mode.
A/R feature to be enabled. TANTRA
NSCO
1. During the 38th PCSC meeting,
TANTRANSCO informed that the Auto
Reclosing facility would be enabled within
15 days.
2. A/R scheme will be implemented after
the commissioning of 400 kV Thiruvalam
Line-I & II.
Pending
34/I/3 Tripping
of HVDC
Bhadrav
ati Pole-1
& 2
09-07-2014 As reported, pole-1&2 tripped due to
auxiliary supply failure.
1. The PCSC forum recommended PGCIL, SRTS-I take up the
issue with WRTS to submit the report as per IEGC guidelines.
2. SRLDC is also requested to write a letter to WRLDC to submit
the reports to SR also.
3. Based on the SRTS/SRLDC correspondences, SRPC would
take it up with WR and PGCIL if the issue is not getting resolved.
4. Complete analysis of the faults and rectification/remedial
action taken to avert similar occurrence in the HVDC Back to
Back station shall be submitted.
PGCIL 1. Implementation of Tertiary Winding of
ICT for the auxilliary power supply is going
to come up which resolves this issue.
2. PGCIL informed that all issues would be
discussed during PSAG-11 visit.
Pending
Kerala
PGCIL
ANNEXURE-III
6 PCSC-42
34/I/7 HVDC
BHADR
AVATH
I POLE 2
18-07-2014 As reported pole-2 tripped due on 5th
harmonic alarm.
1. Complete analysis of the faults and rectification/remedial
action taken to avert similar occurrence in the HVDC Back to
Back station shall be submitted.
2. The PCSC forum recommended PGCIL, SRTS-I take up the
issue with WRTS to submit the report as per IEGC guidelines.
3. SRLDC is also requested to send a letter to WRLDC to submit
the reports to SR also.
4. Based on the SRTS/SRLDC correspondences, SRPC would
take it up with WR and PGCIL if the issue is not getting resolved.
PGCIL Yet to be informed Pending
39/I/1 Tripping
of 400kV
Gooty-
Somanah
alli
22-11-2014 Line tripped due to
suspected PLCC
Mal-operation at Gooty
end.
Retrofitting of the relay or installation of Optical Fiber cable is
recommended by PCSC forum to PGCIL.
PGCIL Yet to be informed Pending
40/II/1 Tripping
of 400kV
Vijayawa
da-
Gajuwak
a
line
18-12-2014
at
18:33 hrs
Line tripped due to operation of TEED
protection at Gajuwaka end due to
opening of jumper of Y phase CT.
PGCIL shall review the TEED protection at Gajuwaka end
and submit the details to PCSC forum.
PGCIL Yet to be informed Pending
41/II/1 Tripping
of 400kV
Vijayawa
da-
Nellore
line 1
22-01-2015
at 11:39 hrs
line tripped on operation of TEED
protection at Vijayawada end and direct
trip was received at Nellore end
review the TEED protection at Vijayawada
end with their OEM group and submit action taken report to
PCSC forum.
PGCIL Yet to be informed Pending
ANNEXURE-III
7 PCSC-42
41/II/6 Tripping
of 400kV
Coastal
Energen
(CEPL)---
NTPL
line
07-02-2015
at 01:07 hrs
and at
00:08hrs on
08-02-2015
B-phase to earth fault had occurred in
Line during both instants. As seen from
D.R of Coastal Energen distance relay
sensed fault in zone-2 and earth fault
protection had operated which resulted
in tripping of line.
to carry out hot-line washing regularly as NTPL is
in highly polluted location.
PGCIL Yet to be informed Pending
41/II/8 Tripping
of HVDC
Talcher-
Kolar
pole-2
10-02-2015
at 7:37 hrs
Pole-2 tripped due to ESOF from
Talcher end
test the pumps at Talcher HVDC during pole
shut-down and submit the report to PCSC forum.
PGCIL Yet to be informed Pending
41/II/16 Tripping
of 400
kV
NEYVE
LI TS 2 -
PUGAL
UR
15-02-2015
at 18:38 hrs
Line tripped at pugalur end due to
direct trip receive
PGCIL to check the protection coupler of PLCC system at
Pugalur end.
PGCIL Yet to be informed Pending
41/III/1 Tripping
of 400kV
Gooty-
Somanah
alli line
20-01-2014
at 11:44 hrs
line tripped at Gooty end only and was
holding from Somanahalli end line
• PGCIL to furnish remedial measures taken.
• PGCIL to properly tune PLCC panels.
PGCIL Yet to be informed Pending
ANNEXURE-III
8 PCSC-42
41/III/2 Tripping
of 400kV
Udumalp
et-
Palakad
line-1&
400
Udumalp
et-Arasur
line-2
09-02-2015
at 9:50hrs
PLCC of Udumalpet-Arasur-2 mal-
operated
• PGCIL to furnish remedial measures taken.
• PGCIL to properly tune PLCC panels.
PGCIL Yet to be informed Pending
37/I/9 Tripping
of
400/220k
V ICT-
1&2 at
UPCL
04-10-2014 ICT-1&2 tripped during transient fault
in R-phase in 400kV Hassan-UPCL
line-1
To avoid tripping of ICTs for line fault, UPCL is requested to
review the settings of ICT’s SEF relay and consider IDMT
setting instead of existing Definite Time setting.
UPCL It has been reported by UPCL that, the work
of review of relay coordination and setings
for the entire plant is given to M//s Alstom
for entire plant. UPCL has furnished the
settings given by M/s Alstom for
verification. Revised settings will be issued
this week for implementation
Pending
40/II/8 Tripping
of Unit-1
at
Kudankul
am
14-01-2014
at
19:20 hrs
Y-phase Differential protection of
Generating transformer of Unit-1 got
operated which resulted in tripping of
Unit-1.
1. NPCIL, Kudankulam was recommended to submit all the
relevant reports of the above incident.
2. PCSC forum also requested NPCIL, Kudankulam to upload all
the reports (DR/EL/ FIR) of any incident in the SRLDC web
portal within 24 hrs of its occurrence.
NPCIL,
Kudankula
m
Yet to be informed Pending
41/II/10 Tripping
of
Hassan-
UPCL
line-2
12-02-2015
at 15:57 hrs
Line tripped due to high resistance fault
in B-phase. DEF picked up at hassan
end and DT was sent to UPCL. DEF
protection did not pick up at UPCL
revise their DEF relay settings. UPCL Yet to be informed Pending
Others
ANNEXURE-III
9 PCSC-42
41/II/12 Tripping
of
400KV
Coastal-
NTPL
line
13-02-2015
at 22:54 hrs
Line tripped B-phase to earth fault and
later tripped on R-Y phase fault. From
Coastal end D.R, Y & B poles of
breaker opened first and R-pole
appears to be opened on Pole
discrepancy.
check A/R scheme at their end. CEPL Yet to be informed Pending
41/IV/2 400kV
Tuticorin
PS-NTPL
line
09-02-2015
at 03:17 hrs
Y-phase to earth fault had occurred in
line. Line auto reclosed at Tuticorin PS
end and failed to reclose at NTPL end.
NTPL to check A/R scheme at their end. NTPL Yet to be informed Pending
36/II/8 400kV
Raichur-
Muniraba
d line
07-09-2014 B-phase to earth fault had occurred in
line.
Line auto reclosed at Munirabad end
and failed to reclose at Raichur end.
KPTCL:
PD (pole discrepancy) time delay would be changed.
PGCIL /
KPTCL
Yet to be informed Pending
37/I/6 Tripping
of
400KV
Hassan-
UPCL
line-2
25-09-2014
Back up earth fault protection had
operated at Hassan.
At UPCL end the high resistance fault
got converted into a R ph-B-ph fault
which resulted in operation of distance
protection Zone-1.
The reason for non-picking up of Back
up earth fault at UPCL needs
investigation.
1. At UPCL end, unused zones of distance protection
(probably zone 5 to 8) shall be disabled.
2. At UPCL end, time synchronization between main-1 and
main-2 relays shall be ensured.
3. UPCL shall ensure time synchronization with Hassan
substation.
4. Reasons for non operation of back up protection at UPCL
for high resistance fault is to be submitted.
5. Reasons for not sending DT to UPCL by Hassan end is to
be submitted.
6. Settings of UPCL are to be reviewed and informed to PCSC
UPCL /
KPTCL
It has been reported by UPCL that, the work
of review of relay coordination and setings
for the entire plant is given to M//s Alstom
for entire plant. UPCL has furnished the
settings given by M/s Alstom for
verification. Revised settings will be issued
this week for implementation.
Pending
38/II/2 Tripping
of 400kV
Khamma
m-
Kalpakka
line
11-10-2014 Line tripped on Yphase
to earth fault.
reclose at Khammam
end.
APTRANSCO and TSTRANSCO were requested to clear the
corridor jointly at the earliest.
PGCIL/
APTRANS
CO/
TSTRANS
CO
Yet to be informed. Pending
Miscellaneous
ANNEXURE-III
10 PCSC-42
38/II/5 400kV
Ramagun
dam-
Hyderaba
d line-4
27-10-2014
to earth fault.
reclose at Hyderabad
end due to
PLCCmal-operation.
Planned to replace the PLCC system within a week's time at both
the ends during the shutdown.
NTPC/
PGCIL
Yet to be informed. Pending
39/I/2 Tripping
of
400Kv
Ghanapur-
Mamidip
ally
line
22-12-14
at 10:52 hrs,
24-12-14 at
11:32
hrs,
24-12-14 at
16:16 hrs
Due to PLCC Mal-operation at HYD
S/S end, DT received at MMPLY end
and line got tripped.
PGCIL is requested check up with the manufacturer to resolve
the issue and submit remedial measures to PCSC forum.
PGCIL/
TSTRANS
CO
Yet to be informed. Pending
40/II/3 Tripping
of 400
kV
TALAG
UPPA
–
HASSA
N line
01-01-2015
at
13:38 hrs
On account of R-phase to earth fault,
line
tripped at Hassan end due to operation
of
distance Zone-2 and non-receipt of
carrier. From D.R of Talaguppa end it
is
observed that fault had occurred in
Yphase.
1. PGCIL and KPTCL to ascertain the reason for the phase
discrepancy in the relay operation and take suitable remedial
measures.
2. KPTCL to check the PLCC operation at Talaguppa end and
submit the report to the PCSC forum.
PGCIL/
KPTCL
Yet to be informed Pending
41/I/2 Complete
outage at
220kV
Bahoor
Substatio
n of
Pondiche
rry (GD-
1)
15-02-2015
at 11:20 hrs
Bus fault occurred in 110kV bus at
230/110kV Bahoor substation due to
failure of Y-phase main bus strain
insulator. 220kV lines connected to
Bahoor (viz., Bahoor- NLC TPS II and
Bahoor – Pondy) tripped from remote
end on operation of back up protection.
1. PED to investigate the cause of non-operation of ICT’s
protection system (differential protection, back-up
protection) and review the relay settings suitably.
2. PGCIL to check the settings of distance relay and back-up
relays for correctness of operation.
PED/PGCI
L
Yet to be informed Pending
ANNEXURE-III
11 PCSC-42
41/II/3 Tripping
of 400kV
NLC-1
EXP-
IL&FS
line and
400kV
IL&FS -
Trichy
line
24-01-2015
on 13:15 hrs
400kV NLC-1 EXP- IL&FS line
tripped on a R-phase to earth fault.
Line did not auto-reclose. 400kV
IL&FS - Trichy line tripped at Trichy
due to Direct trip receive from IF&FS.
action taken
report on the recommendations given by SRPC Committee in
their meeting held at IL&FS on 19-02-2015 to SRPC.
IL&FS /
PGCIL (SR-
II)/ NLC-1
Exp
Yet to be informed Pending
41/II/5 Tripping
od 400
kV NLC
EXP-
ILFS line
05-02-2015
at 06:05 hrs
Line tripped due to direct trip receipt
from IL&FS
action taken
report on the recommendations given by SRPC Committee in
their meeting held at IL&FS on 19-02-2015 to SRPC.
IL&FS /
PGCIL (SR-
II)/ NLC-1
Exp
Yet to be informed Pending
Tripping
of 400kV
NTPL-
Tuticorin
pooling
station
13-02-2015
at 23:12 hrs
Line tripped on R-phase to earth fault
at 22:53 hrs. Line auto reclosed at
Tuticorin pooling end and holding. At
23:12 line tripped on B-phase to earth
fault in zone-2 time.
Tripping
of 400kV
NTPL-
Tuticorin
pooling
station
14-02-2014
at 1:41 hrs
B-phase to earth fault had occurred and
line auto reclosed at 01.09 Hrs and
holding from Tuticorin PS end and line
was and up hand tripping at 01.44.
41/II/13,
41/II/14,
41/II/15
PGCIL to carry out hot-line washing regularly as NTPL is
in highly polluted location.
NTPL to review A/R scheme at their end.
PGCIL/NT
PL
Yet to be informed Pending
ANNEXURE-III
12 PCSC-42
Tripping
of 400kV
NTPL-
Tuticorin
pooling
station
14-02-2014
at 6:55 hrs
Line tripped on B-phase to earth fault.
Line did not reclose at NTPL end
41/II/13,
41/II/14,
41/II/15
PGCIL to carry out hot-line washing regularly as NTPL is
in highly polluted location.
NTPL to review A/R scheme at their end.
PGCIL/NT
PL
Yet to be informed Pending
ANNEXURE-III
13 PCSC-42
S.N
o.
Element Name Outage
date/time
Revival
date/time
Reason for Outage Sender/
Receiver
Remedial Measures/ Actions taken
1 400/220 Kv ICT-1
AT SATTENAPLLI
26-02-
2015/
10:19:00
26-02-
2015/
11:30:00
GROUP - A
PROTECTION
OPERATED
TSTRANS
CO
To-be-discussed
2 400 Kv
SATTENAPALLI -
SRISAILAM 2
04-03-
2015/
14:25:00
04-03-
2015/
15:08:00
R-N FAULT TSTRANS
CO/
TSGENCO
To-be-discussed
3 220 kV CHITTOR -
THIRUVALEM
19-03-
2015/
15:18:00
19-03-
2015/
15:46:00
TRIPPED ON R-PH
FAULT
APTRANS
CO/ TNEB
TANTRANSCO: Temporary line
fault.
APTRANSCO:
4 220 kV
AMBEWADI -
PONDA 1
19-03-
2015/
18:55:00
REASON TO BE
STATED LATER
KPTCL To-be-discussed
5 400 kV GOOTY -
NELAMANGALA
19-03-
2015/
14:24:00
19-03-
2015/
14:44:00
TRIPPED B-PH
FAULT
PGCIL
(SR-I)/
KPTCL
To-be-discussed
6 220 kV
AMBEWADI -
PONDA 1
20-03-
2015/
12:40:00
DISTANCE
PROTECTION
RELAY ACTED
KPTCL To-be-discussed
Pending Remedial Measures/ Actions taken
for the Critical Tripping Incidents (as on 16.04.2015)
ANNEXURE- IV
1
7 400 kV
TALAGUPPA -
NEELAMANGALA
20-03-
2015/
13:37:00
20-03-
2015/
14:07:00
DISTANCE
PROTECTION
ACTED (REASON
AWAITED)
KPTCL To-be-discussed
8 220 kV
SABARGIRI -
THENI
20-03-
2015/
13:08:00
20-03-
2015/
13:46:00
TRIPPED ON R-Y-
PH FAULT
KSEB/
TNEB
TNEB: Temporary line fault. AR
operated & subsequently lockout at
Theni end. KSEB:
9 400 Kv
KRISHNAPATNAM
- NELLORE
20-03-
2015/
03:02:00
DISTANCE
PROTECTION
APGENC
O/
APTRANS
CO
To-be-discussed
10 400 Kv
KRISHNAPATNAM
- CHITTOOR
20-03-
2015/
05:05:00
20-03-
2015/
05:29:00
DT RECEIVED AT
KRSNPTNM
APGENC
O/
APTRANS
CO
To-be-discussed
11 400 kV
KHAMMAM -
MAMIDIPALLY 1
21-03-
2015/
13:09:00
21-03-
2015/
13:56:00
B -N FAULT PGCIL
(SR-I)/
TSTRANS
CO
PGCIL (SR-I):The feeder Auto
reclosed and tripped on B-N persistent
fault in line.
TSTRANSCO:
12 400 kV KAIGA -
GUTTUR 1
21-03-
2015/
17:44:00
21-03-
2015/
18:44:00
DT RECEIVED AT
KGA END
KAPS/
KPTCL
To-be-discussed
ANNEXURE- IV
2
13 400 kV KAIGA -
GUTTUR 2
21-03-
2015/
20:03:00
21-03-
2015/
20:30:00
DT RECEIVED AT
KGA END
KAPS/
KPTCL
To-be-discussed
14 400 kV KAIGA -
GUTTUR 2
21-03-
2015/
17:44:00
21-03-
2015/
18:58:00
DT RECEIVED AT
KGA END
KAPS/
KPTCL
To-be-discussed
15 400 kV
KHAMMAM -
KALPAKKA 1
22-03-
2015/
14:05:00
22-03-
2015/
20:55:00
B-N FAULT PGCIL
(SR-I)/
APTRANS
CO
PGCIL (SR-I): The feeder Auto
reclosed and tripped on B-N persistent
fault in line
APTRANSCO:
16 400 kV
KHAMMAM -
KALPAKKA 2
22-03-
2015/
12:53:00
22-03-
2015/
13:28:00
R - N FAULT PGCIL
(SR-I)/
APTRANS
CO
PGCIL (SR-I): The feeder Auto
reclosed and tripped on B-N persistent
fault in line
APTRANSCO:
17 400 kV
KHAMMAM -
KALPAKKA 2
22-03-
2015/
14:45:00
22-03-
2015/
20:57:00
B-N FAULT PGCIL
(SR-I)/
APTRANS
CO
PGCIL (SR-I): The feeder Auto
reclosed and tripped on B-N persistent
fault in line
APTRANSCO:
ANNEXURE- IV
3
18 400 kV
KHAMMAM -
MAMIDIPALLY 1
22-03-
2015/
12:01:00
22-03-
2015/
20:21:00
B - N FAULT PGCIL
(SR-I)/
TSTRANS
CO
PGCIL (SR-I): The feeder Auto
reclosed and tripped on B-N persistent
fault in line
TSTRANSCO:
19 400 kV
KHAMMAM -
KALPAKKA 1
22-03-
2015/
13:36:00
22-03-
2015/
13:58:00
B-N FAULT PGCIL
(SR-I)/
APTRANS
CO
PGCIL (SR-I): The feeder Auto
reclosed and tripped on B-N persistent
fault in line
APTRANSCO:
20 400 kV
KHAMMAM -
MAMIDIPALLY 1
25-03-
2015/
18:32:00
25-03-
2015/
19:15:00
B-N FAULT PGCIL
(SR-I)/
TSTRANS
CO
PGCIL (SR-I): The feeder Auto
reclosed and tripped on B-N persistent
fault in line
TSTRANSCO:
21 220 kV
AMBEWADI -
PONDA 2
25-03-
2015/
16:15:00
DISTANCE
PROTECTION
KPTCL To-be-discussed
22 400 kV KAIGA -
GUTTUR 1
27-03-
2015/
13:40:00
27-03-
2015/
15:26:00
TRIPPED WHILE
CHECKING RELAY
KGS/KPT
CL
To-be-discussed
ANNEXURE- IV
4
23 400 Kv RAICHUR
PG - GOOTY 1
28-03-
2015/
19:34:00
28-03-
2015/
19:52:00
TRIPPED DURING
RELAY TESTING
AT RAICHUR
PGCIL
(SR-I)
To-be-discussed
24 220 kV
AMBEWADI -
PONDA 1
28-03-
2015/
11:01:00
28-03-
2015/
11:24:00
TRIPPED ON B-N
FAULT
KPTCL To-be-discussed
25 400/220 kV ICT-2
AT MAHABOOB
NAGAR
28-03-
2015/
06:40:00
RESTRICTED
EARTH FAULT
TSTRANS
CO
To-be-discussed
26 400 Kv ALM -
SVCTM-II
29-03-
2015/
15:29:00
29-03-
2015/
16:51:00
B -N FAULT TNEB R-N fault at the time of 400 kV
Alamathy - Sunguvarchatram - I
Feeder tripping. (Both the feeders in
the same tower).
ANNEXURE- IV
5
27 400/230 Kv ICT-1
AT
SUNGUVARCHAT
RAM
29-03-
2015/
15:29:00
29-03-
2015/
16:32:00
OVER FLUX
PROTECTION
OPERATED
TNEB It is 400/110kV ICT-3 at
Sunguvarchatram. On 29.03.2015 @
15.29.38Hrs., 400/110KV,
3×66.67MVA, ICT-3 tripped on V/f
trip due to sudden rise in voltage
(around Va=321 & Vc=333KV) and
actuation of V/f Trip of ICT-3 occurs
few milliseconds after the fault
tripping of 400KV Alamathy-1 Feeder
and 400KV Alamathy-2 feeder. ICT-3
was put back into service at 16:30:18
Hrs
28 400 Kv ALM -
SVCTM-I
29-03-
2015/
15:29:00
PHASE TO PHASE
FAULT
TNEB Line Fault due to jumper cut in B
phase. Feeder normalised on
30.03.2015 @ 12:10 hrs. after
attending the fault.
29 220 kV
AMBEWADI -
PONDA 1
30-03-
2015/
13:10:00
30-03-
2015/
20:40:00
B - N FAULT KPTCL To-be-discussed
30 400 Kv VTPS -
MALKARAM 2
30-03-
2015/
11:51:00
30-03-
2015/
20:41:00
R -N FAULT APGENC
O/
TSTRANS
CO
To-be-discussed
ANNEXURE- IV
6
31 400/220 kV ICT-1
AT BTPS
31-03-
2015/
05:06:00
REASON AWAITED KPCL To-be-discussed
32 400 kV KURNOOL -
SRISAILAM
01-04-
2015/
15:01:00
01-04-
2015/
15:30:00
B-N FAULT APTRANS
CO/
TSGENCO
To-be-discussed
33 400 kV
HYDERABAD -
KURNOOL
01-04-
2015/
13:01:00
01-04-
2015/
13:45:00
TRIPPED PGCIL(SR-
I)/
APTRANS
CO
To-be-discussed
34 400 kV
HYDERABAD -
KURNOOL
01-04-
2015/
15:01:00
01-04-
2015/
17:34:00
TRIPPED PGCIL(SR-
I)/
APTRANS
CO
To-be-discussed
35 400 kV KURNOOL -
SRISAILAM
01-04-
2015/
13:01:00
01-04-
2015/
13:46:00
B-N FAULT APTRANS
CO/
TSGENCO
To-be-discussed
36 220 kV IDUKKI -
UDUMALPET
03-04-
2015/
16:39:00
03-04-
2015/
17:25:00
TRIPPED ON B-PH
FAULT
KSEB/
TNEB
TNEB: Temporary fault due to heavy
rain at Edukki area. AR operated &
Lockout at Udumalpet end.
KSEB:
ANNEXURE- IV
7
37 400 Kv NCTPS -
VALLUR 2
03-04-
2015/
22:10:00
DIFFERENTIAL
PROTECTION
OPERATED
TNEB/
NTECL
TNEB: No visible fault. AR operated
& holding at Vallur end.
NTECL:
38 400 kV
DICHIPALLY -
RAMAGUNDAM
05-04-
2015/
13:43:00
05-04-
2015/
22:23:00
R - N FAULT TSTRANS
CO/ NTPC
NTPC: The line tripped on R-N fault
at 13:43 Hrs on 5/4/2015. An attempt
was made to charge from Dichipally
end at 15:40 hrs. But it tripped on
SOTF. APTRANSCO have informed
that they rectified the fault.
Subsequently, it was charged from
DICHIPALLY end, but it has tripped
on over voltage at ramagundam end.
Finally the line was charged from
RDM end at 22:30 hrs and
subsequently synchronized at
dichipally end.
APTRANSCO:
39 400 kV GUTTUR -
NARENDRA 2
06-04-
2015/
17:07:00
06-04-
2015/
17:23:00
H/T BY MISTAKE
BY NARENDRA
OPERATOR
KPTCL/
PGCIL
(SR-II)
To-be-discussed
40 220 kV SEDAM -
TANDUR
06-04-
2015/
13:53:00
06-04-
2015/
16:25:00
OCR OPERATED KPTCL/
TSTRANS
CO
To-be-discussed
ANNEXURE- IV
8
41 400 Kv NCTPS -
VALLUR 2
07-04-
2015/
02:41:00
DIFFERENTIAL
PROTECTION
OPERATED
TNEB/NT
ECL
To-be-discussed
42 400 Kv NCTPS -
VALLUR 2
07-04-
2015/
23:13:00
TRIPPED ON Y-PH
FAULT
TNEB/NT
ECL
To-be-discussed
43 400 Kv NCTPS -
VALLUR 1
08-04-
2015/
22:28:00
TRIPPED ON R-PH
FAULT
TNEB/NT
ECL
To-be-discussed
44 HVDC TALCHER -
KOLAR POLE
09-04-
2015/
12:04:00
09-04-
2015/
14:18:00
CONVERTER
TRANSFORMER R
PHASE OLTC PRD
OPERATED
PGCIL
(SR-II)
To-be-discussed
45 765 KV RAICHUR -
KURNOOL
10-04-
2015/
18:45:00
10-04-
2015/
21:16:00
Y-B FAULT PGCIL
(SR-I)
To-be-discussed
46 400 Kv
KAYATHAR -
KARAIKUDI 1
11-04-
2015/
09:58:00
SF6 LEAKAGE IN
REACTOR
BREAKER
TNEB To-be-discussed
47 400 kV
TALAGUPPA -
NEELAMANGALA
11-04-
2015/
02:22:00
11-04-
2015/
02:49:00
Y-N FAULT KPTCL To-be-discussed
ANNEXURE- IV
9
48 400 kV
MAHABOOB
NAGAR -
RAICHUR
11-04-
2015/
18:07:00
11-04-
2015/
18:50:00
TRIPPED ON R-PH
FAULT
TSTRANS
CO /KPCL
To-be-discussed
49 400 Kv NCTPS -
VALLUR 1
11-04-
2015/
04:29:00
DIFFER
PROTECYION IN R-
EARTH DUE TO
FOG & 220 KV LINE
TRIPPING DUE TO
FOG
TNEB/NT
ECL
To-be-discussed
50 765 KV RAICHUR -
KURNOOL
11-04-
2015/
18:04:00
11-04-
2015/
18:55:00
TRIPPED ON Y-B
FAULT
PGCIL
(SR-I)
To-be-discussed
51 220 Kv
REGULAPADU-
ALIPUR LINE
11-04-
2015/
18:13:00
11-04-
2015/
19:20:00
EFR RELAY ACTED APTRANS
CO/
KPTCL
To-be-discussed
52 220 kV SEDAM -
TANDUR
11-04-
2015/
18:12:00
11-04-
2015/
19:36:00
EFR RELAY ACTED KPTCL/
TSTRANS
CO
To-be-discussed
53 400 kV RAICHUR -
BTPS
11-04-
2015/
17:42:00
11-04-
2015/
19:02:00
TRIPPED ON B-PH
FAULT
KPCL To-be-discussed
ANNEXURE- IV
10
54 400/110 kV ICT 2
AT ALAMATHY
11-04-
2015/
11:30:00
11-04-
2015/
17:31:00
SF6 GAS LEAKAGE TNEB To-be-discussed
55 400 Kv RAICHUR
PG - GOOTY 2
11-04-
2015/
18:04:00
TRIPPED AT RCR
END DUE TO LA
FAILURE
PGCIL
(SR-I)
To-be-discussed
56 400 Kv NCTPS -
VALLUR 1
12-04-
2015/
03:47:00
DISTANCE
PROTECTION
TNEB/NT
ECL
To-be-discussed
57 220 kV IDUKKI -
UDUMALPET
12-04-
2015/
01:43:00
12-04-
2015/
02:18:00
B PHASE
DISTANCE
PROTECTION
KSEB/
TNEB
To-be-discussed
58 220 kV IDUKKI -
UDUMALPET
12-04-
2015/
15:12:00
12-04-
2015/
16:26:00
B-N FAULT KSEB/
TNEB
To-be-discussed
59 400 Kv NELLORE -
SPDR
12-04-
2015/
20:37:00
12-04-
2015/
21:11:00
R-N FAULT PGCIL
(SR-I)/
PGCIL
(SR-II)
To-be-discussed
60 400 Kv HASSAN -
UPCL 1
12-04-
2015/
12:58:00
12-04-
2015/
13:23:00
TRIPPED ON B-PH
FAULT
PGCIL
(SR-II)
/KPTCL
To-be-discussed
61 220 kV
GUMMUDIPUNDI -
SULLURPET
13-04-
2015/
17:15:00
13-04-
2015/
17:37:00
DISTANCE
PROTECTION
TNEB/
APTRANS
CO
To-be-discussed
62 400 kV ALAMATHI
- VALLUR 1
13-04-
2015/
19:43:00
DISTANCE
PROTECTION
TNEB/NT
ECL
To-be-discussed
ANNEXURE- IV
11
63 400 Kv HASSAN -
UPCL 1
14-04-
2015/
11:08:00
14-04-
2015/
11:39:00
TRIPPED ON B-PH
FAULT
PGCIL
(SR-II)
/KPTCL
To-be-discussed
64 400 kV
GHANAPUR -
MAMIDIPALLY
14-04-
2015/
03:42:00
TRIPPED AT MDPL
END ONLY
PGCIL
(SR-I)
/TSTRAN
SCO
To-be-discussed
65 400/220 kV ICT-1
AT BTPS
14-04-
2015/
01:09:00
MAIN
PROTECTION
OPERATED
KPCL To-be-discussed
66 220 kV
YERANDAHALLY -
HOSUR
14-04-
2015/
19:12:00
14-04-
2015/
19:37:00
B - N FAULT KPTCL/T
NEB
To-be-discussed
ANNEXURE- IV
12