f-3, midc area, andheri (east), mumbai - 400 093 durbaaya ... · during detailed checking it was...
TRANSCRIPT
Baart sarkarGovernment of India kond`Iya ivaVut p`aiQakrNa
Central Electricity Authority piScama xao~Iya ivaVut saimait
Western Regional Power Committee ef -3, emaAayaDIsaI xao~, AMQaorI (pUva-), mauMba[- - 400 093
F-3, MIDC Area, Andheri (East), Mumbai - 400 093
Aa[- esa Aao : 9001-2000 IS/ISO : 9001-2008
dUrBaaYa Phone: 022- 28221681; 28200194/195/196; fO@sa Fax : 022 – 28370193 Website : www.wrpc.nic.in E-mail : [email protected]
¬¸¿‰¡¸¸: £®¸μ¸ / 111 œ¸ú¬¸ú‡Ÿ¸ / 2011 / œ¸®¸½¹¨¸¬¸¢Ÿ¸¢÷¸-3474 ¹™›¸¸¿ˆÅ :25.04.2011 No. : Prot./ 111 PCM / 2011 / WRPC- 3474 Date: 25.04.2011
¬¸½¨¸¸ Ÿ¸½¿ /To,
As per mailing list ¹¨¸«¸¡¸:- ¢™›¸¸¿ˆÅ 15 eva 16 maaca- 2011 kao piScama xao~Iya ivaVut saimait mauMba[-U Ÿ ½̧¿ Aayaaoijat kI ga[- £®¸μ¸
¬¸¹Ÿ¸¹÷¸ ˆÅú 111 ¨¸ì b¸¾“ˆÅ ˆÅ¸ ˆÅ¸¡¸Ä¨¸¼î¸— Sub :- Minutes of 111th Protection sub-Committee Meeting held on 15th & 16th March 2011 at
WRPC Mumbai. Ÿ¸−¸½™¡¸ / Sir,
ƒ¬¸ œ¸°¸ ˆ½Å ¬¸¸˜¸ ¢™›¸¸¿ˆÅ 15 eva 16 maaca- 2011 kao piScama xao~Iya ivaVut saimait mauMba[-U Ÿ¸½¿ Aayaaoijat kI ga[- £®¸μ¸ ¬¸¹Ÿ¸¹÷¸ ˆÅú 111 ¨¸ì b¸¾“ˆÅ ˆÅ¸ ˆÅ¸¡¸Ä¨¸¼î¸ ‚¸œ¸ˆÅú ¬¸»c¸›¸¸ ‡¨¸¿ ‚¸¨¸©¡¸ˆÅ ˆÅ¸£Ä¨¸¸ƒÄ í½÷¸º ¬¸¿¥¸Š›¸ í¾ —
Please find enclosed herewith the minutes of 111th Protection sub-Committee Meeting of Western Regional Power Committee, held on 15th & 16th March 2011 at WRPC Mumbai for your information and necessary action.
¤¸¾“ˆÅ ˆÅ¸ ˆÅ¸¡¸Ä¨¸¼î¸ œ¸®¸½¢¨¸ ¬¸¢Ÿ¸¢÷¸ ˆÅú ¨¸½¤¸¬¸¸ƒ’ www.wrpc.nic.in œ¸£ ž¸ú „œ¸¥¸¤š¸ í¾ — Minutes are also available at WRP Committee website www.wrpc.nic.in
š¸›¡¸¨¸¸™ /Thanking you
ž¸¨¸™ú¡¸/Yours faithfully,
sd/- (‡ma.Aar.isMah /M.R. Singh)
‚š¸ú. ‚¹ž¸.(£.)/Suptdg. Engr.(P.) ¬¸¿¥¸Š›¸ /Encl. :- „œ¸£¸½Æ÷¸¸›¸º¬¸¸£ /As above
MINUTES OF THE 111th PROTECTION COMMITTEE MEETING
The 111th Protection Committee Meeting of WRPC was held on 15th and 16th March 2011 at WRPC
Mumbai. The list of participants is placed at Annex -I.
Shri Manjit Singh, Member Secretary, WRPC, welcomed all the members and the
participants of the 111th Protection sub-Committee Meeting. He hoped that various protection
related issues would be resolved through active deliberations in the meeting.
He requested Shri Satyanarayan S. Superintending Engineer (O&S), WRPC to take up Agenda items
for discussions.
Item No.1: Confirmation of Minutes of 110th Protection Committee Meeting.
S.E. (O&S), WRPC, stated that the Minutes of 110th PCM, held on 29th and 30th September 2010 at
Reliance Energy Ltd., Dahanu, were circulated vide WRPC letter no. Prot./110 PCM/2010/WRPC-9626 dated 21st
October 2010. No comments were received from any of the members and as such the minutes were confirmed
without modifications.
Item No.2: System disturbances
2.1: System disturbances in CSPTCL/CSPGCL system.
2.1 (i) System disturbance at 400kV Bhilai S/S in CSPTCL system on
30-12-10.
PGCIL representative informed that on 30.12.2010 at 05:51hrs., 400kV Bhilai-Raipur-I line tripped
from both ends on operation of Main-I & LBB protections at Bhilai end and DT received at Raipur end. Due to
the operation of LBB at Bhilai end, all the lines connected to Bus-II tripped.
He further told that during investigation, it was found that the LBB relay trip wire behind the
cabinet had came out of lug and touched the nearby +ve terminal causing the operation of LBB scheme,
thereby tripping all the lines connected to Bus-II. There was no interruption, since the S/S has a One & Half
Breaker scheme.
Normalcy was restored at 09:05hrs of 31.12.10 Committee felt that wirings need to be checked during routine maintenance work/relay
testing works to avoid such occurrences.
2.2: System disturbances in GETCO/GSECL system.
2.2 (i) System disturbance at 220kV Nanikhakhar S/S in GETCO system on
10-11-10.
GETCO representative informed that on 10.11.10 at 09:15hrs., all the feeders connected to Bus A
tripped from opposite end on E/F & R-Ph Zone-2. All the feeders connected to Bus A were hand tripped
(manually) at 220kV Nanikhakhar S/S.
He further told that the Nakhatrana- Nanikhakhar line no.2 was under planned shut down for line
& bay maintenance work. The LCP was issued for line work. The Line staff was instructed to make local
earthing. However, the bus isolator of Bus A was not opened. Also, all other feeders were connected to Bus
A & bus coupler breaker were ON thus the Bus B remained in charged condition. Unfortunately, during local
earthing victim entered in induction zone (i.e. trying to discharge live part). The incidence resulted in to bus
fault. Subsequently all other feeders connected to Bus A tripped from opposite end on E/F & R-Ph Zone-2
and hand tripped (manually) at Nanikhakhar end.
The retrofitting of the Bus Bar scheme was done in Nov.10 and was kept under observation (the
tripping circuit of the BB scheme was kept isolated), since it was being commissioned. The Bus Bar
protection scheme was taken into service after checking and testing the same.
All the tripped elements were taken restored by 11:45hrs., except the 220kV Nakhatrana-
Nanikhakhar line no.2, which was taken into service at 22:35hrs.
Committee observed that the occurrence was due to human error and felt that supervisor
should accompany the line staff while carrying out work, which could spot such mistakes. The trippings
from remote end were in order, since the Bus Bar protection scheme was not in service.
2.2 (ii) : System disturbance at 220kV Talangpore S/S in GETCO system on 15-11-2010. GETCO representative informed that on 15.11.2010 at 13.20 Hrs, Electrician climbed on the top
plate of 100 MVA 220/66 kV T/F-IV and came into induction zone near LV Y ph bushing at 220kV
Talangpore S/S. All the lines connected to Bus-A & Bus-B tripped from remote end on operation O/C & E/F
protection. The T/F-I & IV tripped from LV side on HS E/F trip.
He further informed that it was concluded that the body of transformer got charged through
Electrician, who climbed on the transformer near LV Y Phase bushing and came into induction zone
/touched LV Y Phase bushing. Due to this control cable of transformer (i.e. OLTC, transformer troubles,
REF Y-ph CT) got damaged and the fuses of Differential Relay (ABB make RET 670), Back up Relay (ABB
make REX 521) were blown off and therefore the transformer tripped from LV side only and did not trip on
Diff/Back up relays. The LV side Y ph bushing and gear mechanism of Y ph tap changer of T/F-IV also got
damaged.
During detailed checking it was found that the Areva makes Differential relay (Micom P632)
which was provided on 100 MVA 220/66 KV T/F-I failed. The Diff Relay of T/F-I was replaced on
16.11.10.
All the tripped elements were restored by 14:30hrs, except T/F which was taken into service at
19:12hrs of 19.11.2010, after attending and confirming the cable, bushing and testing the differential & back
up relays of the transformer.
Committee felt that the fast acting differential protection of the transformer should have
operated ahead of the LV backup protection, to prevent such kind of incidents. The tripping of T/Fs on
LV Backup protection and lines from remote ends on O/C & E/F was in order due failure of Differential
protection of T/F-IV. Committee further felt that the standard safety & operation procedures already
available be followed to avoid such occurrences, e.g. in this case the transformer ladder should have
been locked to avoid easy entry on top of a charged transformer.
2.2 (iii) System disturbance at 220kV Dhrangadhra S/S in GETCO system on 16-11- 2010. GETCO representative informed that on 16.11.2010 at 22:25 Hrs. the B- Ph. P.T connected on
Bus – 2 failed at 220kV Dhrangadhra S/S.
He further informed that the Bus bar protection operated correctly & tripped all the feeders
connected to bus B along with bus coupler breaker. The 220 KV Dhrangadhra – Chorania line no.1 which
was connected to Bus -1 also tripped on distance protection i.e. B-Ph. Zone-1.
All the tripped elements were restored by 01:20hrs of 17.11.2010 except Bus-2 which was
charged on 21/22/10 at 13.50 hrs., after replacement of bus P.T. The relay on 220 KV Dhrangadhra –
Chorania line no.1 was tested & found in order.
Committee observed that the tripping was in order except the tripping of 220 KV
Dhrangadhra – Chorania line no.1 connected to Bus -1 on B-Ph. Zone-1 distance protection.
2.3: System disturbance in MPPTCL/MPPGCL system.
2.3(i) System disturbance at 220kV Barwaha S/S and adjacent 220kV S/Ss in
MPPTCL system on 11-12-2010.
MPPTCL representative informed that on 11.12.10 at 06:35hrs the 220kV Barwaha-Omkareshwar
line tapped to Nimarmani S/S sensed the fault at Barwah end on Y-Ph,Z-I and backup E/F but the ABCB did
not trip due to air leakage. However it tripped at Omkareshwar end on Y-ph,Z-I carrier aided trip and tripped
at Nirmani S/S on carrier received from Barwaha. All the lines connected to 220kV Barwaha S/S tripped
from remote end in Z-III and back up protection. The 220kV Julwaniya-Nimrani tripped at Julwaniya end on
back up O/C.
He further informed that, due to delayed opening of 220kV Barwaha-I MOCB at 400kV Indore S/S,
LBB protection operated and 220kV Indore(E) and Dewas feeders connected to Bus-II tripped. The 220kV
Chhegaon-Nirmani ckt.-I&II was kept open at Chhegaon end and 220kV Khandwa-Omkareshwar line was
kept at Khandwa end prior to fault for managing the load.
At 400kV Indore S/S the BHEL make MOCB provided on 220kV Barwaha ckt.-I has opened
with a delay, causing the operation of LBB and tripped the 220kV Indore(E) and Dewas feeders. Generators
at Omkareshwar power station tripped on over fluxing causing interruption to Julwaniya S/S. The breakers at
220kV and 400kV Indore S/S were tested and the problems associated with the mechanism were rectified.
LBB scheme is not provided at 220kV Barwaha S/S, the same is now being provided. All the
MOCBs at 400kV Indore S/S are planned for replacement.
All the tripped elements were restored by 07:45hrs.
Committee observed that the trippings were in order, since LBB scheme is not provided at
Barwaha S/S. Further it felt that the LBB scheme should be provided at 220kV Barwaha S/S and
regular routine maintenance of the ABCBs & MOCBs should be carried out.
2.3(ii) System disturbance at 400kV Nagda S/S in MPPTCL system on 25-12-2010.
MPPTCL representative informed that on 25.12.10 at 13:52hrs the 220kV Indore-Jaitpura-II
tripped from both end on Z-I, DPS. The load of this line was shifted on 220kV Indore-Jaitpura II line. The
220kV Indore-Jaitpura II line tripped from Jaitpura end on TOC B ph operated.
The load on 220kV Indore-Jaitpura-I&II and 400/220kV 3x315MVA T/F was 211MW, 236MW
& 220MW respectively, prior to the above trippings at Nagda S/S. Due to tripping of the lines the load on
3x315MVA T/F-I, T/F-II & T/F-III increased to 447MW, 369MW & 369MW respectively. The T/F-I & II
tripped from LV side on O/C and from HV side on Group-I trip. The T/F-III tripped on Group-I&II trip along
with O/L relay from HV side and tripped on Inter trip from LV side.
The stage-I & stage-II of the overload scheme provided on 315MVA T/Fs operated. In stage-I
of the overload scheme 100MVA 220/33kV T/F, 132kV A lot fdr & 132kV Mahidpur feeders emanating
from 220kV Nagda S/S and 132kV Salina feeder emanating from 220kV Ratlam S/S are covered. A load
relief of only 10MW was available through stage-I. The Stage-II of the overload scheme covers interstate
feeder 220kV Modak, 220kV Modak-Kota and 220kV Neemuch-I&II feeders emanating from 400kV Nagda
S/S. The stage-II O/L carrier signal was transmitted to Ujjain, but signal was not transmitted to Ujjain-Barod
link due to problem in NFBX contactor of the NSD-61 protection coupler. Also 220kV Neemuch-I&II did
not trip at 400kV Nagda S/S, resulting in no load relief on operation of Stage –II of O/L scheme. A load of
around 1107MW was affected due to the above trippings in Nagda & Ujjain area.
He further told that the overloading scheme at 400kV Nagda S/S ICTs was reviewed and
revised. The interstate 220kV Kota and Modak feeders emanating from 220kV Badod S/S have been
configured in stage-I overload scheme, which operates at definite time of 2.5 sec delay when loading of any
of ICTs at 400kV Nagada crosses 500Amps on 400kV side, configuration of T/Fs and feeders at 220kV
Nagda and Ratlam connected in stage –I has not been changed, so that overload relief in stage-I is sufficient
enough to avoid forced outage of ICTs. The NFBX contactor unit 9code-III) of NSD 61 protection coupler at
220kV Nagda S/S was replaced. The carrier signal transmission from Nagda to Badod was checked and
found in order.
In addition to above , load dropping scheme at 220kV Jaitpura S/S has been configured such
that outage of any one circuit in 220kV Indore-Jaitpura-I&II , the load dropping scheme would operate and
trip all the outgoing 33kV feeders & 132kV Depalpur-I&II feeders at 220kV Jaitpura S/S to control the load
flow
Normalcy of the affected area was restored by 14:30hrs.
Committee observed that even after operation of the stage-I & stage-II overload scheme
provided on 3x315MVA ICTs at Nagda S/S, the required load relief was not obtained. The revision in
the overload load trimming scheme with reference to inclusion of 220kV Modak & 220kV Kota
interstate/inter regional tie lines emanating from 220kV Modak S/S, in stage-I is undesirable and the
same may be included in stage –II of the overload load trimming scheme. Adequate load relief may be
obtained in both the stages.
2.4: System disturbance in MSETCL/MAHAGENCO system.
2.4(i) System disturbance at 400kV Lonikand S/S in MSETCL system
on 07-08-2010.
(This occurrence would have been covered in the 110th PCM. However since it was reported recently
it has been included in this agenda)
MSETCL representative informed that on 07.08.2010 at 03:54hrs the LBB protection of the 400kV
Lonikand-Karad line operated at 400kV Lonikand S/S resulting in tripping of all the elements connected to Bus-B.
He further informed that at 03:54:06:743hrs Y-ph to ground fault occurred on 400kV Lonikand-
Karad line. The fault was sensed by DPS and the Y ph pole of CB tripped at Lonikand end, the same pole got auto
reclosed at 03:54:07:751hrs. A 3 phase auto reclose lockout command was initiated by the DPS at 03:54:07:915hrs
due to persisting fault (Fault current of 4kA was recorded) and the fault was isolated from both ends. At
03:54:08:132hrs the Y pole of the CB got closed unwarrantedly at Lonikand end and was tripped on lockout shot
03:54:08:206hrs. At 03:54:08:369hrs the Y-pole of CB again got reclosed and lockout shot was initiated by the
DPS, however it could not trip due to air pressure lockout, thereby feeding the fault. This resulted in operation of
LBB of the Karad line at Lonikand end.
During detailed investigation it was found that 56V was appearing across the Y pole breaker closing
coil whenever bus and line isolators were closed, due to DC leakage in the cable. The anti pumping relay coil of
the CGL make SF6 breaker was found burnt. The closing coil resistance of R & B pole was 138ohms and that of Y
pole was 130ohms. All the relevant field tests of the CB and DPS schemes were carried out and were found in
order. No abnormality was observed during patrolling. Trial was taken at 18:53hrs, but it tripped on SOTF. At
loc.No.212, decapping of Y-ph insulator string was found during subsequent patrolling.
All the tripped elements were restored by 05:48hrs., except 400kV Lonikand-Karad which was
restored at 12:14hrs of 09.08.10.
Committee felt that the operation of LBB protection because of air pressure lockout (due
to repeatedly closing and tripping of the Y-pole) was in order. However during routine
maintenance/testing the auxiliary systems associated with the equipment under test and cables should
be checked/tested.
2.4(ii) System disturbance at 400kV Koradi S/S in MSETCL system
on 06-09-2010.
MSETCL representative informed that the disturbance occurred in the Nagpur circle of
MSETCL and there is no representation from Nagpur testing Circle for this meeting and hence it can not be
explained in detail.
The disturbance was as follows;
On 06.09.2010 at 10:01 hrs, heavy sound was heard from the yard along with smoke near the
Bus PT. All breakers connected to 220kV Main Bus II tripped due to operation of 220kV Main Bus-II Bus
Bar protection at 400kV Koradi S/S.
At the time of the occurrence a group of monkeys were found near the Bus PT. It is suspected
that monkey might have climbed the Bus PT thereby creating the Bus fault. The GT-V connected to 400kV
Bus tripped due to failure of auxiliaries because of tripping of T/F-4, connected to Bus-II. There was a loss
of generation of 60MW and 139MW due to tripping of GT-2 and GT-V respectively.
Normalcy of Main Bus 2 bays was restored by 15:07hrs except the 400/220kV, 315MVA ICT
due to burnt series resistance of the trip circuit.
Committee felt that since there was inadequate representation from MSETCL the disturbance
can not be discussed and the same would be taken up for discussion in the next PCM. It was also felt
that Utilities should depute adequate representation for the meeting.
2.4(iii) System disturbance at 400kV New Koyana S/S in MSETCL system
on 25-10-2010.
MSETCL representative informed that the disturbance occurred in the Karad circle of MSETCL and
there is no representation from Karad testing Circle for this meeting and hence it can not be explained in
detail.
The disturbance was as follows;
On 25.10.2010 at 00:46 hrs, the IPS tube between C-isolator to line isolatorof 400kV New-
Koyana-Jaygad ckt#1 fell down due to heavy sparking at C Bus isolator resulting in operation of Bus bar Z-
II, thereby tripping all the elements connected to Bus-II.
The 400kV New Koyna-Karad Ckt.#1 tripped in Zone-3 along with 400/220/33kV ICT-II
connected to Bus-I.
During yard inspection the IPS tube connected between C-isolator to D-isolator of 400kV New
Koyna-Jaygad ckt#1 was fallen on the metal spreading in the yard and a big pit was formed.
All the tripped elements were restored by 03:41hrs except 400kV Jaygad ckt.#1, 400kV
Karad-II and Jejuri were restored at 05:13, 09:09 and 12:04hrs respectively.
Committee felt that since there was inadequate representation from MSETCL the disturbance
can not be discussed and the same would be taken up for discussion in the next PCM. It was also felt
that Utilities should depute adequate representation for the meeting.
2.5: System disturbance in PGCIL system.
2.5 (i) System disturbance at 400kV Khandwa S/S in PGCIL system on
10-09-2010.
PGCIL representative informed that on 10.09.2010, at 03:01Hrs, the 400kV Khandwa-Seoni-2
feeder Tie CB was hand tripped and subsequently the main CB was also hand tripped due to high system
voltage conditions as per the CPCC/WRLDC instructions. However within few seconds of opening, Main
CB B-pole bus side interrupter chamber blasted.
There was a continuous arcing for around 14 sec around the 400kV Khandwa-Seoni-2 feeder
B-pole of main CB. This resulted in intermittent unbalance current & voltage in B phase of the line.
Because of this, NGR Buchholz protection operated frequently due to continuous flow of unbalance current
to ground.
He further told that the Seoni-2, Itarsi-2 & Dhule-2 lines tripped on O/V stge-1 protection.
This resulted in tripping of all the 400kV lines connected to Khandwa. However the Bus remained charged
through ICTs (220kV) system and maintained the arcing around the B-pole. The LBB of this CB failed to
operate. The B phase of line remained charged from Khandwa end due to continued arcing in B pole of
Main CB at Khandwa end, resulted in high voltage at Seoni end causing Zone-2 earth fault (after around 9
to 10 sec) because of failure of LA at Seoni end, which was sensed by both Main-1 &2 protections of
Seoni-2 line at Khandwa end. After around 11 seconds from start, CB pole got blasted resulting in loss of
SF6 gas. Ultimately, after around 14 seconds from start, fault got cleared because of tripping of 220kV line
from remote end in Zone-2.
The Bus Voltage of Khandwa S/S remains quite high (in the range of 430kV) and the breaker
might have failed due to dielectric failure because of re strike voltage developing during hand tripping
under high system voltage conditions.
During the last AMP (in Jan’10), this relay was tested and was healthy. LBB (ABB’s RAICA)
relay was again tested and it was found that the B ph ‘RXIB24’ module was faulty; the same was replaced
with healthy spare module and relay made healthy again.
The detailed report is enclosed at Annex.-2.5 (i)
Committee felt that the SF-6 gas in the breaker pole might have lost its dielectric strength
during/prior to opening of the pole and the prevailing system voltage and re striking voltage across the
pole might have led to the breakdown of the dielectric thus maintaining the arc around the pole.
2.6: System disturbance in TATA/Mumbai system.
2.6 (i) System disturbance at 220kV Trombay S/S in TATA system on
18-11-2010 & 21-11-2010.
TATA Power representative informed that on 18.11.2010, at 17:39Hrs, the 220kV Trombay-
Salsette#1 tripped due to kite string fault in span 70-71 at Tagorenagar Vikhroli.
220kV Trombay-Salsette#2 tripped only at Salsette at 17:46hrs on DPS. 220kV Trombay-
Salsette#1 tripped from both ends on DPS. 300MW of load on Salshette-Borivali corridor got shifted to
110kV MSETCL Borivali & 220kV MSETCL Boisar interconnection. 220kV MSETCL Borivali-TATA
Borivali line no.4 was kept open since 19.10.10 due to problem in MSETCL system. This resulted in
tripping of MSETCL Borivali ICTs & 220kV MSETCL Boisar-Reliance lines on overload. Thus, islanded
Reliance Dahanu system alongwith its generating units did not survive. Around 800MW load in Western
suburb got affected.
Restoration was started at 17:46hrs and the Dahanu units were synchronized at 21:18hrs.
He further told that on 21.11.2010 at 17:05Hrs, 220kV Trombay-Dharavi#5 & Trombay-
Salsette#2 tripped on fault. At 17:10 hrs., 220kV Trombay-Dharavi#6 tripped probably due to inclement
weather. This led to tripping of other connected lines on overload resulting in shutdown to Dharavi &
Vikhroli S/Ss and parlty Mahalaxmi & Backbay S/Ss.
MERC has constituted a Committee to look into the disturbance and suggest remedial
measures.
A detailed presentation on the above occurrence was given and is enclosed at Annex- 2.6 (i).
Committee felt that after finalization of the report of the MERC formed Committee, the
same may be studied and implementation of remedial measures to be suggested therein be ensured by
the concerned agencies.
2.7 : Grid Incidences and Grid Disturbances classification as per the Grid Standards notified by CEA.
SE (O &S) informed that POSOCO WRLDC vide their letter No. WRLDC/OS/2010/1658 Dtd.
03.02.2011 have categorized the Grid Incidents and Grid Disturbance for the period September-December
2010.
As per above standards appropriate Load Dispatch Center’s (LDC’s) shall intimate Regional
LDC/State LDC which would further inform all concerned. Regional LDC shall classify Grid Incidents (GI)
and Grid Disturbances (GD) and inform WRPC at the earliest for discussion in PCM. The present practice of
reporting to WRPC in PCM format may also be continued.
Some of the incidences were discussed as follows.
2.7 (i) : System disturbance at 220kV Mundra S/S in APL system on
15-08-2010.
APL representative informed that on 15.08.2010, at around 16:32Hrs, the Bus coupler R-phase
conductor connected to CT snapped off from the twin clamp joint and got disconnected from the CT.
220kV Lines-1, 3 & 4 tripped from remote end on Distance protection. 220kV. Line-4 tripped on distance
protection ( phs-stfw l1, phs-stfw l2,phs-stfw l3 indication) at 220kV Mundra end.
The prefault & fault currents recorded on the 220kV lines 1, 2, & 3 were 1129.55A & 1137.94A;
849A & 922A & 236A & 314A respectively.
The Bus coupler did not trip, however Earth fault relay start and Over Current Relay start
indication appeared. At 6:32:00:750, 400kV APL-Sami #2 APL side tie breaker tripped on LBB-3ph. and
Main breaker tripped on over current (R-Phase). At 6:32:01:527, APL-Sami Ckt-2 at Sami end tripped on
distance protection (L1) Z1 (427.2Km). At 6:32:06, GT-1 tripped on over current and stator 100% E/F,
subsequently Boiler-1 tripped on Furnace flame loss. GT-2 tripped on over current and stator 100% E/F,
subsequently Boiler tripped on all FD fan Off. GT-3 tripped on generator main protection and boiler-3
tripped on flame loss.
He further informed that the Bus Bar protection did not operate, since it went into CT open
Blocking state. The time setting for CT open Blocking adopted is instantaneous. The pre fault Power Flow
through 220kV bus coupler was around 408MW.
Unit-1 was lighted up at 12:05Hrs and synchronised at 13:27hrs. (Delayed due to leakage repair
job on RH spray NRV). Unit-2 lighted up at 10:18hrs and synchronised at 11:20hrs. Unit-3 light up
delayed due to various leakage repair jobs in turbine side.
SE(O&S) informed that under Item 2.1(iv), while discussing the disturbance at 220kV KLTPS
S/S on 07.04.2010 in GETCO system, the Committee observed that switching OFF of the 220kV Adani-
Tappar lone No.1 (due to melting of Y-ph isolator jaws and hot spot observed at Adani end) without
informing to SLDC Gotri aagravated the problem thereby stressing the system. Further Committee felt that
the area controller of the Adani System is SLDC Gotri, hence SLDC should be informed for taking such
outages.
APL representative informed that the requirements as per the Grid standards will be
followed rigorously.
Report received from APL is enclosed at Annex- 2.7 (i).
Committee observed as follows;
(i) The Bus Bar protection should have operated and isolated the fault. The fault currents recorded on
220kV Lines 1, 2 & 3 suggest that the fault was highly resistive in nature initially. The snapping of the
conductor opened the primary of the CT and current of R-ph became zero and since the pre fault flow
in the BC was significant, hence the BB scheme might have detected an open CT. However the time
setting adopted to block the BB on CT open detection should never be kept instantaneous, to take care
of faults initially of highly resistive and eventually getting into solid ground faults. The Committee
suggested that the BB Block on CT Open should be kept within 3-5sec, as is the practice in the region.
(ii) Tripping of 220kV Line-4 on distance protection was incorrect since it had sensed the fault in
reverse direction. Hence the relay settings/configuration needs to be checked.
(iii) 400kV APL-Sami CKT-2 APL side tie breaker tripping on LBB-3ph. and Main breaker tripped
on over current (R-Phase) was incorrect. Also tripping of 400kV APL-Sami Ckt-2 at Sami end on
distance protection (L1) Z1 (427.2Km) was incorrect since it overreached. Hence the relay settings at
both ends should be reviewed.
(iv) In view of relay setting problems at APL Mundra S/S as above, it was felt that APL should
review the relay settings at this S/S.
2.7 (ii) : System disturbance at 400kV Dabhol S/S in RGPPL system on
23-08-2010 & 24-08-2010.
RGPPL representative informed that on 23.08.2010, at around 17:15Hrs, the steam cabinet
Power Supply fail appeared. Generator lock out relay 86G3 operated.
The GT#1A, GT#1B & STG#1X was operating in combined cycle mode. The control system
GT#2A, GT#2B & STG#2X was being upgraded. Instead of uploading the constants in the STG#2X
control system through software, it was uploaded in STG#1X.
The time taken to come on turning gear is 41 minutes.
He further told that on 24.08.2010, at 05:57:38.844 hrs, Inadvertent Reverser Energisation lock
out activated. The Generator Breaker tripped at 05:57:38.922hrs followed by Master turbine protective trip
(L4T) at 05:57:38.953hrs.
The GT#1A, GT#1B & STG#1X was operating in combined cycle mode. On investigation it was
found that the STG#1X, Reverser Energisation Relay was configured for over current mode with setting of
120% and mark VI return NC contact for speed > 95%. The STG#1X was operating at base load with both
gas turbines in service. The tripping of 400kV Dabhol-Nagothane#1 caused the generator current more
than 120% momentarily resulting in picking up of Reverser Energisation Relay. The Reverser Energisation
Relay setting were corrected for over current mode with setting of >20% and mark VI speed < 95%. The
unit was synchronized at 12:14hrs
Committee felt that any software up gradation system should have password protection
and other interlock so that the person upgrading the system may become alert thereby avoiding
such mistakes.
ITEM NO. 3: Tripping of lines / ICTs:
The incidences of tripping of lines and ICTs during the period 01-09-2010 to 31-12-2010 were discussed
during the meeting.
Observations of the committee are enclosed at Annexure –3.
ITEM NO. 4: Protection related recommendations on Grid Disturbances in Western
Regional Grid on 25.2.2007 at 1634 hours and 28.2.2007 at 13:11 hours:
Protection related recommendations of the Enquiry Committee on Grid Disturbances
in Western Regional Grid on 25.2.2007 at 1634 hours and 28.2.2007 at 13:11 hours were
reviewed during the meeting and the present status regarding implementation of
recommendations is placed at Annexure-4.
ITEM NO. 5: Other points:
5.1: Non-availability of Event Logger at 400kV state owned sub-stations at
Nagda, Indore, Bina Padghe, Kolhapur, Koradi, Chandrapur, Dhule and
Bhilai. S.E. (O&S), WRPC informed that in the 104th PCM, PGCIL had informed that Event Loggers at some of
the 400kV state owned Sub stations, namely Nagda, Indore, Bina of MPPTCL, Padghe, Dhule, Kolhapur, Koradi,
Chandrapur of MSETCL and Bhilai of CSPTCL are not provided. PGCIL have requested for early installation of
Event Loggers at these stations.
He further told that in the 106th PCM, MPPTCL representative clarified that event loggers available in
the numerical relays as a built in feature, and GPS synchronized clock are being used for logging the events at all
the above S/S’s, hence they are not initiating the procurement process for separate event loggers for the above
S/Ss. However members of PCM felt that a separate event logger is required to be installed so that all the events
occurring required for post fault analysis of an occurrence in the S/S can be recorded. In the 107th PCM MPPTCL
desired to have a list of events that are required to be logged. As desired by MPPTCL the list of events that are
required to logged was enclosed at Annex. 5.3 of the 107th PCM minutes. In the 109th PCM, MPPTCL
representative informed that the proposal has been moved to the management and decision is awaited.
In 110th PCM, MPPTCL representative informed that the event loggers for Nagda, Indore, Bina and
Bhopal were in tendering process and would be commissioned within 3-4 months.
MPPTCL representative informed that the event loggers for Nagda, Indore, Bina and Bhopal were in
tendering process and would be commissioned within 3-4 months.
In the 107th PCM, MSETCL representative informed that event logger for Padghe and Kolhapur and
Dhule has been commissioned. Further the event loggers at Koradi, Chandrapur and Khaparkheda have been
provided, but unit outages from the generating stations are awaited for incorporating the events of generating
units. MSETCL and MSPGCL representatives agreed to co ordinate for the same.
In the 108th PCM, MSETCL representative informed that necessary coordination with MSPGCL was
done, however during commissioning of the scheme problems in the scheme were reported and the same would be
sorted out and the event loggers would be put in service shortly. In the 109th PCM, MSETCL representative
informed that the provision of event loggers at 400kV Dhule S/S is pending and will be commissioned by the last
week of July 2010.
In the 110th PCM, MSETCL representative informed that event loggers have been commissioned at
400kV Dhule S/S in July 2010. The event loggers at Koradi, Chandrapur and Khaparkheda S/Ss have been
installed and were kept under observation for 15-20days and they would be commissioned within a month.
MSETCL representative informed that the event loggers for 400kV Dhule S/S, Koradi, Chandrapur
and Khaparkheda S/Sshave been commissioned.
In the 109th PCM, CSPTCL representative informed that the event logger for Bhilai is under procurement
stage and would be commissioned within 6 months. In 110th PCM.
In the 110th PCM CSPTCL representative informed that the event logger was under procurement stage
and would be commissioned within 3-4months.
CSPTCL representative informed that the event logger was under procurement stage and would be
commissioned within 3-4months.
Committee felt that the installation of Event Loggers at above S/S, may please be commissioned at
the earliest.
5.2: Pending SOE connections and erroneous data in SCADA. S.E. (O&S), WRPC informed that the matter was first discussed in the 102nd PCM, with reference to the
pending SOE connections it was opined that the constituents should confirm the availability of hardware at RTU’s
for incorporating the extension of MTR contacts to the SOE inputs of the RTU, in addition to the CB contacts
which are also required to be transmitted.
During 105th PCM, committee felt that, WRLDC may circulate the list of those locations from where
erroneous data is received and the locations where SOE connections are yet to be established at the earliest so
that corrective actions could be taken up by constituents and the progress of the same could be monitored.
In the 106th PCM WRLDC representative intimated that the list had already been
circulated to the respective State LDCs. He further told that in view of MTR contacts being used
by some of the constituents as inputs for the SOE connections, all the constituents may
incorporate MTR contacts only for SOE connections. During the 107th PCM members expressed
that the list was not made available to them hence the list of locations from where erroneous
data is received and locations where SOE connections are yet to be established was enclosed at
Annex.-5.4 of the 107th PCM minutes.
In the 108th PCM, PGCIL representative stated that they have rectified the problems as
per the list. GETCO representative informed that work is in progress and 90% problems have
been rectified. MPPTCL representative informed that work is in progress and 80-90% of the
problems have been attended. MSETCL representative informed that work is in progress.
The list of status of SOE and erroneous data points was reviewed in the meeting and the remedial actions
suggested by Utilities were as follows:
(i) 220kV Kawas (NTPC)- NTPC representative informed that the SOE points connected to CB would
be configured through Master Trip within 10-15 days.
(ii) 220kV Vindhyachal (NTPC)- NTPC representative informed that the SOE points connected to CB
would be configured through Master Trip within 10-15 days.
(iii) 400kV Mapusa (PGCIL)- PGCIL representative informed that the SOE points connected to CB
would be configured through Master Trip within 10-15 days.
(iv) 400kV Wardha (MSETCL)- MSETCL representative informed that the SOE points connected to
CB would be configured through Master Trip within 10-15 days.
(v) 400kV Sipat and 220kV Jhanor- Committee felt that the matter may be taken up with PGCIL and
NTPC separately, since representatives were not present.
In the 110th PCM, Committee felt that Utilities should take corrective actions as above and further
observed that the status which is not getting updated at WRLDC through SCADA may be taken up by WRLDC in
the SCADA committee meetings for its rectifications.
POSOCO WRLDC vide their letter dated 03.02.2011 have intimated that the matter has been taken up in
the SCADA Committee meeting held on 01.01.11, and constituents would give presentations on the data position
in the next SCADA Committee meeting.
As such this issue would now be followed up in the SCADA Committee meeting.
Committee noted the same.
5.3: Problem in Bus bar protection scheme at Korba (W) CSPGCL S/S. (i) S.E. (O&S), WRPC informed that NTPC vide their letter KS/EM/ETL/2405/615109/285
Dtd.05.05.09 have informed that NTPC Korba and CSPTCL Korba(W) substations are connected with a 400kV
line of line length 14Km. On 04.05.09 at 02:51hrs bus fault occurred (one of the CT of inter connecting
transformer blasted) at CSPTCL end. The NTPC 400kVKorba- CSPTCL Korba (W) line tripped in zone-2 from
NTPC Korba end, thus feeding the fault current of around 14KA for the timing of zone-2. Inter trip or direct trip
signal was also not received from Korba (W) S/S. Similar fault had occurred at 400kV Korba (W) S/S on 09.09.08
at 11:48 hrs also and was fed for zone-2 timing from NTPC Korba S/S since the Bus bar protection is not
available, the fault was fed for longer time..
Earlier in the 107th PCM, CSPTCL representative informed that the Bus Bar scheme is out of
service since last one year, due to faulty Bus Bar scheme and burnt control cables at 400kV Korba (W) S/S and
have initiated the process for procurement of the same. Committee felt that the commissioning of Bus Bar
protection scheme at the above S/S may be expedited.
In the 108th PCM, CSPGCL representative informed that the Bus Bar protection scheme for 400kV
Korba (W) has been included in their business proposal submitted to the Chhattisgarh State Electricity Regulation
Committee (CSERC) and after approval from CSERC the scheme process for procurement of the scheme would
be taken up. However Committee felt that in view of the criticality of the matter and importance of the 400kV
Korba (W) S/S from the WR system protection point of view, the Bus Bar protection scheme at 400kV Korba (W)
S/S, might be taken up as a special case to CSERC and necessary approval may be obtained on priority.
Follow up was made by WRPC vide letter No WRPC/Prot./PCM/2010-11/1013Dtd. 13th Aug 2010.
Also the matter was put up before the 14th WRPC Board Meeting and CSPGCL was requested to expedite the
matter.
In 110th PCM, CSPGCL representative informed that the earlier proposal of BB protection scheme
was for 8 bays and in view of commissioning of 6 new bays at this S/S, the proposal has been modified for
14bays. It is expected that approval of CSERC would be received in one month and the procurement process
would be initiated immediately. During the 111th PCM, representative from CSPGCL was not present..
(ii) The Grid Connectivity Standards applicable to the Transmission line & Substation-part-III(3)
stipulates that two main numerical Distance Protection Scheme shall be provided on all the transmission lines of
220kV and above for all new S/Ss. Bus bar protection shall be provided at all S/Ss at and above 220kV level for
all new S/S. For existing lines & S/Ss these shall be implemented in a reasonable time frame.
PGCIL informed that Bus bar protection at 220kV Navasari and Vapi S/S are not in service.
GETCO representative told that Bus bar protection at 220kV Vapi S/S is in service and 220kV
Navasari S/S has single Bus system & do not have any plan of providing another Bus, hence Bus bar protection at
220kV Navasari S/S is not required.
Representatives told that the above notification is being implemented for all new S/Ss and
retrofitting of the DPS on existing lines has been taken up in phased manner.
Committee noted the above and felt that since there was no representation from CSPGCL the
matter may be taken up with CSPGCL for expediting the work.
5.4 : Testing of Distance Protection Schemes for lines emanating from Kawas to
GETCO.
S.E. (O&S), WRPC informed that in the 107th PCM, the matter of testing of the Distance Protection
Schemes along with the PLCC feature for the lines emanating from Kawas S/S to GETCO system was
discussed. PGCIL representative informed that the issue would be resolved through meeting with GETCO to
facilitate testing the Distance protecting scheme jointly with GETCO, as the PLCC panels are imported ones
and the spares are not available.
GETCO vide their letter No. CE(TR)/SE(Testing)/Bharuch-2/493 Dtd.16.03.10, have intimated that,
in view of the importance of the issue the same needs to be resolved at the earliest.
As decided in the 108th PCM, a meeting was held at NTPC Kawas on 22.06.2010.
In the 109th PCM the Committee went through the recommendations of the group.
It was decided that the cost of PLCC and installation at NTPC end would be done by
NTPC and the remote ends by PGCIL, in line with common specifications as per the
existing practice being followed at old stations. Other points of above minutes of
meeting were also accepted by the Protection sub-Committee.
The matter was put up to the WRPC Board in the 14th WRPC Board meeting, and
the same was approved.
In 110th PCM, GETCO representative requested that the DPS at PGCIL end is faulty and corrective
actions are required to be taken by PGCIL. PGCIL representative told that LOA was awarded for
replacement of the DPS and the relays would be replaced within 1-2 months at Haldarva, Vav and Navasari
ends. NTPC representative told that the DPS at 220kV Kawas has been replaced by Areva Micom make
DPS.
PGCIL representative informed that the DPS on Haldarva, Vav and Navasari ends have been
replaced with Areva P442 DPS. NTPC & PGCIL representative informed that the procurement
process for PLCC equipment has been started as per the decisions taken in the meeting held at NTPC
Kawas on 22.06.2010. As such Committee felt that the issue of commissioning of PLCC at NTPC
Kawas has now been resolved.
5.5 : Carrier aided inter trip protection for 220kV line of JGGPP:
S.E. (O&S), WRPC informed that NTPC vide their letter No QSR/OS/WRPC/F17 Dtd. 08.04.10,
have informed that the existing distance relay provided are zone operated and there is no provision for
carrier aided inter trip. In case of end zone faults at Haldarva end, the relays at Haldarva end senses the fault
in zone-I and operates instantaneously, where as the relays at JGGPP senses the fault in zone-II and clear the
fault after 300ms in the absence of the carrier aided inter trip protection. This results in dip in the Bus
voltage and high vibration in the ST generator bearings.
In view of the above NTPC has requested to incorporate the carrier aided inter trip protection
scheme for the 220kV Jhanor-Haldarwa D/C lines.
In the 109th PCM, PGCIL representative told that the carrier inter-trip protection is available in the
distance relay at Haldarva end. The same was recently checked and the same is in working condition.
However some cards of the PLCC scheme are missing at JGGPP end and requested NTPC to check up the
same. Committee requested NTPC to check up the PLCC scheme at their end.
In the 110th PCM, NTPC representative told that permissive trip testing has been done at both ends.
DT testing would be done during the next opportunistic shut down.
NTPC representative told that DT testing was also carried out and the carrier inter trip has
now been taken into service.
Committee noted the same.
5.6 : A/R scheme of 400kV Tarapur – Boisar ckt. 1 & 2 and 400kV Tarapur –Padghe ckt 1 & 2 at
Tarapur NPCIL end.
(i) A/R at TAPS and remote ends.
S.E. (O&S), WRPC informed that PGCIL vide their letter No WRTS/O&M/R/141/132 Dtd.
23.08.2010 have informed that the matter of keeping the A/R scheme in auto mode for 400kV Tarapur –
Boisar ckt. 1 & 2 and 400kV Tarapur –Padghe ckt 1 & 2 lines at Tarapur NPCIL was discussed in the 98th
PCM and recorded at item No. 6.01. NPCIL had informed the matter was taken up with BHEL. No
communication in this matter was received from NPCIL TAPS. Committee deliberated in detail on
putting the A/R scheme in non auto mode at Generating S/Ss, in view of the torsional vibrations that
the rotor/prime mover may unnecessarily be subjected, in the event of permanent fault. The
Committee suggested that for lines emanating from TAPS the provision of auto reclose facility may be
ensured at the remote end of lines to ascertain that the fault is of temporary or permanent in nature.
Therefore Committee recommended A/R feature for 400kV TAPS-Boisar 1 & 2 at Boisar end (already
in service) and A/R for 400kV TAPS-Padghe 1 & 2 at Padghe end. Accordingly A/R for the above
lines at Padghe end may be enabled.
MSETCL representative agreed to keep the A/R scheme at Padghe end in Auto mode.
(ii) A/R with Main & Tie Breaker in Auto mode at Khedamara S/S.
In the 110th PCM PGCIL had informed that Autoreclosing of Tie breakers at Bhilai substation is also
in non-auto mode for POWERGRID lines even after replacement of the old ABCBs. CSPTCL
representative told that when main breaker is kept out the Tie breaker is put in auto mode manually. PGCIL
represented requested to keep the main and tie breaker A/R in auto mode with different time settings. This
practice is being followed at PGCIL S/Ss.
Committee deliberated on providing different A/R time settings for main and tie breakers. It was
felt that the dead timing of main and tie breakers be kept within the pole discrepancy trip timings. Further
the same should be monitored closely. CSPTCL representative agreed to look into the possibility of keeping
the A/R for main & tie breaker in auto mode and revert back.
CSPTCL vide letter No.02-07/WRPC/2625 Dtd. 11.03.11 have informed that Areva make
VARM 111 type relays are in use which are very old and do not have self supervision, event logging
and disturbance recorder feature, hence the same be replaced with latest state of art numerical auto
reclosure relays in order to ensure successful auto reclosing.
Committee opined that the A/R scheme at Khedamara S/Ss be kept in auto mode as suggested
in the 110th PCM and the performance of the Areva make VARM 111 A/R relay be monitored.
PGCIL agreed to replace the above relay after monitoring, if performance was not satisfactory
ITEM NO. 6 : Other Items.
6.1 : Current Differential protection implementation using OPGW instead of Earth wire for
recommending to the PSDF Group.
S.E. (O&S), WRPC informed that, WRLDC had proposed that replacement of old distance
protection schemes with state of art current differential protection scheme using OPGW instead of PLCC
can be taken up under PSDF. The PSDF group discussed the issue in its second meeting held on
19.10.2010 at WRPC Mumbai and suggested that the same may be discussed in PCM and the decisions
of the PCM on this issue appraised to PSDF group of WRPC.
REL representative stated that they are utilizing the current differential protection for
their lines and the performance is very good.
Committee recommended trying the same on experimental basis. Committee further felt that
members from State Transmission Utilities would identify at least two important lines having OPGW,
in their system and intimate the same in the next PCM. Committee further felt that PGCIL may work
out on the detailed proposal (such as specifications, requirement of boosters & multiplexers, estimated
cost etc), so that the same may be appraised to PSDF group of WRPC.
6.2 : Presentation on Mobile Test Laboratory for on-site accuracy testing of EHV class instrument
transformers by Diagnostic, Cables & Capacitors Division of CPRI Banglore.
S.E. (O&S), WRPC informed that CPRI Banglore has established a unique Mobile Test Laboratory
for on-site accuracy testing of EHV class instrument transformers. The Mobile unit is equipped with the
facilities of conducting on-site accuracy testing of CTs and CVTs of accuracy class up to 0.2 as per
National and International standards. The Mobile Test Lab is fitted with high accuracy and high precision
test equipments, current & voltage sources of appropriate ratings for testing of EHV class CTs/CVTs upto
400kV rating in S/Ss and Power Stations.
The Mobile Test Lab is also equipped with automatic system for measurement of Capacitance &
Tan Delta on CTs & CVTs which is useful for periodic testing and trend monitoring in the dielectric
properties in assessing the ageing status of CTs & CVTs.
A presentation given by Shri A. Sudhindra Addl. Director CPRI on the Mobile Test Laboratory is
enclosed at Annex.-6.2(i). The CPRI’s offer with scope of work, terms & conditions and commercial bid
for accuracy testing of CTs/CVTs at sites of WRPC constituents, subsequently received through e-mail is
enclosed at Annex.-6.2 (ii).
He further informed that the the CEA notification dtd. 17.03.2006 had made it mandatory to test the
interface metering once in a five year accordingly Northern Region has identified around 6000 CTs for
testing.
Committee felt that on site accuracy testing of EHV class instrument transformers is
important and may be taken up in two phases. In the first phase the CTs & PTs provided at inter
State & ISGS interface metering points covered in REA of WR be taken up.
Utilities/PGCIL/WRLDC may give the list of such locations with number of instrument
transformers required to be covered under testing. Based on above the implementation plan for the
same be discussed further. In the second phase accuracy testing of EHV class instrument
transformers for State Utilities in their system may be taken up after successful completion of
phase-I.
6.3 : Practices followed for EHV CT maintenance in utilities.
S.E. (O&S), WRPC informed that the EHV S/S CTs failure was being regularly discussed in
almost every PCM and it was felt that practices followed among WR constituents be discussed in PCM.
Accordingly WRPC vide letter No.Prot./110PCM/2010/WRPC-9435 Dtd.01.11.2010 requested the
members of the PCM to forward the practices followed by constituents of WR in maintenance of EHV
class CTs.
The EHV CT maintenances practice followed by utilities is enclosed at Annex. 6.3.
Committee felt that almost all the utilities follow similar practices. If the schedule of routine
maintenance and rigorous implementation of these practices is followed, the failure of CTs can be
minimized. It further felt that newer technologies in the field of maintenance of Protection/Switch
gear equipment followed elsewhere may be shared in the Protection forum for discussion and
continued improvement in Protection System of region.
ITEM NO. 7: Any other issues.
ITEM NO. 8: Date and Venue of the next meeting.
It was decided that the next Protection sub-Committee meeting (112th) will be held in May/June 2011,
wherein system disturbances for the period 01/01/2011 to 31/03/2011 will be discussed. Exact date and
venue will be communicated separately.
ANNEX-I
LIST OF PARTICIPANTS
111th Protection Committee Meeting held on 15th & 16th March 2011 at WRPC Mumbai.
APL (Adani Power Limited)
Shri J. K. Upadhyay Sr.Manager Shri Rakesh Ranjan Sr.Engineer
CPRI (Centra Power Research Institute)
Shri A. Sudhindra Addl. Director (DCCD)
GETCO (Gujarat Energy Transmission Corporation Limited)
Shri J.N.Pancholi Addl. Chief Engineer (Testing)
MAHAGENCO (Maharashtra State Power Generation Company Limited)
Shri A.K.Patil Superintending Engineer (T/F)
MSETCL (Maharashtra State Electricity Transmission Company Limited)
Smt. R.S.Joshi Superintending Engineer (Testing) Pune Shri S.P.Pasarate Superintending Engineer (Testing) Vashi Shri D.P.Nandanwar Dy.EE(T) Vashi Shri Girish Malode Dy EE (Testing) Pune Shri M.D.Kabudle Assist. Engineer (T) Pune
MPPTCL (Madhya Pradesh Power Transmission Corporation Limited)
Shri A.K. Shrivastava Executive Engineer
CSPTCL (Chattisgarh State Power Transmission Co. Ltd.)
Shri M.K.Rai Executive Engineer (MRT), Bhilai
JPL (Jindal Power Ltd.)
Shri Naresh Panjabi GM(Electrical)
NPCIL (Nuclear Power Corporation of India Limited)
Shri Paramanand Barick SE(EM) KAPS Surat
Shri A.N.Thakur SME (E) TAPS-3&4, Tarapur
NTPC
Shri Jitendra Tewari DGM (EMD-I/c) Vindhyachal STPS Shri R.K Aash DGM(EM), Kawas Shri N.P.Dewangan Dy.Supdt.(EM-O&M) Korba
PGCIL (Power Grid Corporation of India Limited)
Shri Anand Dubey Manager, Vadodara Shri Ravi Wadyalkar Dy. Manager, Nagpur
RGPPL-Dabhol
Shri V.V.Venkateshwaran
DGM (EM) RGPPL
TPC (Tata Power Company)
Shri M.V. Kini Assistant General Manager Shri T. Murali Krishna Chief Manager, Trombay, Mumbai
Torrent Power Ahmedabad
Shri Shailesh K. Bhatt Chief Manager(Transmission), Ahmedabad.
REL (Reliance Infra Ltd.)
Shri D.M.Devasthale DGM (Trans), Mumbai. Shri M. R. Waigankar Manager, Mumbai. Shri Pramod V. Rege Manager Dahanu TPS
WRLDC (Western Regional Load Dispatch Centre)
Shri S.R.Narsimhan DGM (OS) Smt. Pushpa Seshadri Manager (OS) Shri Aditya P.Das Sr. Engineer (OS)
WRPC (Western Regional Power Committee)
Shri Manjit Singh Member Secretary Shri O.P.Singh Superintending Engineer (C) Shri Satyanarayan S. Superintending Engineer (O&S) Shri P.D.Lone Assist.Dir.-I(P)
ANNEXURE-3
TRIPPINGS OF LINES / ICTS
Sr. No.
NAME OF S/S
Name of line/ICT
SYSTEM /Provision
of A/R (Yes/No)
Tripping Restoration REASON
Date Time Date Time
1
400 KV Wardha
400 KV Wardha - Akola # 2
PGCIL (Y)
01/09/10 01:48 01/09/10 01:58 Line tripped due to over voltage stage-1 at Akola and D/T received at Wardha.
2
765 KV Seoni
765 KV Seoni - Wardha # 1
PGCIL (Y)
01/09/10 01:48 01/09/10 01:58 Line tripped due to over voltage stage-1 at Wardha and D/T received at Seoni.
3
400 KV Raipur
400 KV Raipur-Sipat #2
PGCIL (Y)
02/09/10 22:30 02/09/10 22:30 Line autoreclosed successfully on R ph-E fault. F/L= 49.7Km from Raipur end.
4 765kV Bina 765kV Bina-
Gwalior#1 (400kV)
PGCIL (Y)
09-04-2010
17:19 09-04-2010 17:19 A/R on B-N fault
5 400kV Khaparkheda
400kV K'kheda-Chandrapur
MSETCL (Y)
09-04-2010
2:51 09-04-2010 2:51 Transient R-N fault. A/R at both end.
6
400 KV Kansari
400 KV Kansari -Kankroli line
GETCO (Y)
09-05-2010
3.1 09-05-2010 5.18 Kansari end: Direct trip receive, Line CVT fuse fail.Kankroli end: Nil
7
400 KV Raipur
400 KV Raipur -Sipat # 1
PGCIL (Y)
06/09/10 16:17 06/09/10 16:17 Line auto reclosed successfully at both ends on R-ph E fault, F.L=26km from Raipur end.
8
400 KV Raipur
400 KV Raipur -Sipat # 2
PGCIL (Y)
06/09/10 16:31 06/09/10 16:31 Line auto reclosed successfully at both ends on B-ph E fault, F.L=24km from Raipur end.
9 400kV Itarsi 400kV Itarsi-
Khandwa#1 PGCIL (Y)
09-09-2010
13:25 09-12-2010 07:57 A/T on operation of OV stg-I at Khandwa end
10 400kV Khandwa
400kV Khandwa-Dhule#1
PGCIL (Y)
09-09-2010
13:25 09-12-2010 07:39 A/T on operation of OV stg-I at Khandwa end
11 400kV Satna 400kV Satna-
Bina#3 PGCIL (Y)
09-09-2010
05:31 13/9/2010 16:08 A/T on operation of OV stg-I at Satna end
12
400 KV Boisar
400 KV Boisar-Vapi
PGCIL (Y)
10/09/10 09:42 10/09/10 09:42 Line auto reclosed successfully at both ends on Yph- E fault, F.L- 83 km from Boisar end.
13 400kV Satna 400kV Satna-
Bina#4 PGCIL (Y)
09-10-2010
07:59 09-10-2010 09:49 A/T on operation of OV stg-I at Bina end
14
400kV V’chal
400kV V’chal-Jabalpur#3
PGCIL (Y)
09-11-2010
11:46 09-11-2010 12:15 A/R at Jabalpur end only & A/T at VSTPP (NTPC) end
15
400 KV Boisar
400 KV Boisar-Vapi
PGCIL (Y)
13/09/10 11:36 13/09/10 12:18 Line auto-reclosed on Yph-E fault sucessfully but tripped again on persisting fault, distance 90.5km from Boisar end.
16
400 KV Ranchi
400 KV Ranchi-Sipat # 1
PGCIL (Y)
14/09/10 14:06 14/09/10 15:10 Line tripped on Yph-E fault, autoreclose unsecussful due to problem in protection system (PT Fuse fail attended) at NTPC Sipat end,distance of fault 50km from Sipat end.
17 400kV Seoni 400kV Seoni-
Khandwa#1 PGCIL (Y)
16/09/2010 15:10 16/09/2010 15:10 A/R on R-N fault
18 400kV V’chal 400kV V’chal-
Jabalpur#2 PGCIL (Y)
16/09/2010 15:12 16/09/2010 15:12 A/R on R-N fault
19 400 KV Ranchi
400 KV Ranchi-Sipat # 1
PGCIL (Y)
17/09/10 14:37 17/09/10 14:47 Line tripped due to Over voltage at Ranchi(ERTS-1)
20 400 KV Ranchi
400 KV Ranchi-Sipat # 1
PGCIL (Y)
18/09/10 05:41 18/09/10 06:27 Line tripped due to Over voltage at Ranchi(ERTS-1)
21
HVDC Bhadrawati
HVDC POLE #1 at Bhadrawati
PGCIL 21/09/10 04:43 21/09/10 08:40 Pole tripped due to AC overcurrent protection operation.Mal operation due to problem in phase control card, rectified the same.
22 HVDC Bhadrawati
HVDC POLE # 1at Bhadrawati
PGCIL 22/09/10 18:42 22/09/10 23:44 Tripped on operation of tap changer protection.
23
220kV TAPS
220kV TAPS-Borivali
MSETCL 22/09/10 12:43 22/09/10 12:53 Line tripped on Cph Z-I & Dir O/C due to kite fault on line. Line had tripped on similar protection on 23.08.10. Relay settings co ordination done.
24 HVDC Bhadrawati
HVDC POLE # 1at Bhadrawati
PGCIL 23/09/10 08:53 23/09/10 12:59 Tripped on operation of tap changer protection.
25 400kV V’chal
400kV V’chal-Jabalpur#4
PGCIL (Y)
23/09/2010 14:18 23/09/2010 16:29 A/T on persisting Y-N fault
26
400kV Chandrapur
400kV C'pur-Parli#2
MSETCL (Y)
23/09/10 18:19 23/09/10 23:20 Transient R-N fault. A/R at both end, but went into L/O due to persistent fault..
27 220kV Kakrapar
220kV Kakrapar-
NPCIL 24/09/10 5:36 24/09/10 6:01 Tripped from both ends in Z-I, Aph-E.
Vapi#1
28
400 KV Asoj 400 KV Asoj-Indore-1
GETCO (Y)
26/9/2010 10.17 26/9/2010 11.24 Asoj end: O/V R & B Ph., Indore end: Carrier receive,
29 400kV Indore
400kV Indore-Asoj#2
PGCIL (Y)
30/09/2010 10:39 30/09/2010 10:39 A/R on Y-N fault
30
HVDC Bhadrawati
Pole 2 at HVDC Bhadravati
PGCIL 02/10/10 16:27 02/10/10 16:36 Pole tripped due to thyristor junction tempearture control protection.
31 400kV Khandwa
400kV Khandwa-Rajgarh#1
PGCIL (Y)
10-03-2010
16:56 10-04-2010 12:43 A/T on operation of OV stg-I at Rajgarh end
32 220kV TAPS
220kV TAPS-Vapi
GETCO 10-03-2010
11:26 10-03-2010 11:55 Tripped on C ph Z-I.
33
400kV Chandrapur
400kV C'pur-Parli#1
MSETCL (Y)
10-04-2010
15:18 10-04-2010 15:18 Transient R-N fault. Line A/R at C'pur end but went in L/O at Parli end.
34
400kV Satpura
400kV Satpura-Indira Sagar
MPPTCL (Y)
10-04-2010
13:27 10-04-2010 14:15 Line tripped on Y-N fault. A/R successful from both ends.
35
400 KV Tarapur
400 KV Tarapur-Padghe # 1
PGCIL (Y)
05/10/10 18:46 05/10/10 19:34 Line tripped on R-E fault; F/L= 15Km from Tarapur. A/R is non auto mode at Tarapur and Padghe end.
36 400 KV Korba
400 KV Korba - Bhilai # 1
PGCIL (Y)
07/10/10 17:13 07/10/10 18:18 Line tripped on receipt of DT.
37 400kV V’chal
400kV V’chal-Satna#1
PGCIL (Y)
13/10/2010 22:34 13/10/2010 22:34 A/R on Y-N fault
38
400kV Satpura
400/220kV ICT MPPGCL 15/10/10 18:30 15/10/10 18:40 Tripped from both sides on operation of 220kV Backup E/F. CT cable problem attended the same.
39
400kV Satpura
400/220kV ICT MPPGCL 15/10/10 18:43 16/10/10 20:22 Tripped from both sides on operation of 220kV Backup E/F. 220kV side CT cables of R&Y ph were found cut and damaged, replaced the same.
40 400 KV Raipur
400 KV Raipur- Raigarh # 2
PGCIL (Y)
17/10/10 16:10 17/10/10 16:20 Line tripped on overvoltage stage-I at Raigarh.
41
400 KV Kasor
400 KV Kasor -GPEC
GETCO (Y)
18/10/2010 12.28 18/10/2010 13.04 Kasor end: O/V stage 1 & 2, A/R lock out GPEC end: Nil
42 400kV Birsinghpur
400kV B'pur-Damoh
MPPTCL (Y)
20/10/10 17:48 20/10/10 18:38 Line tripped on C ph-E fault.
43 220kV Vapi 220kV Vapi-
Kharadpada#1&2 PGCIL (Y)
21/10/2010 07:00 21/10/2010 07:26 A/T on R-N fault
44 400kV Chandrapur
400kV C'pur-Khaparkheda
MSETCL (Y)
21/10/10 18:34 21/10/10 18:34 Transient B-N fault. Line A/R at both ends.
45
400 KV Korba
400 KV Korba-Bhilai # 1
PGCIL (Y)
22/10/10 21:02 22/10/10 21:02 Line autoreclosed successfully on both ends on R-E fault at 191.2 Km from Bhilai.
46
400 KV Seoni
400 KV Seoni-Bhilai (Lilo portion)
PGCIL (Y)
24/10/10 13:02 24/10/10 13:33 Line tripped on Yph -E fault.Fault location= 150km from Seoni end. A/R scheme problem, attended the same.
47
400 KV Seoni
400 KV Seoni-Bhilai (Lilo portion)
PGCIL (Y)
25/10/10 13:23 25/10/10 13:37 Line tripped tripped on Rph -E fault.Fault location= 167km from Seoni end.
48 400kV V’chal
400kV V’chal-Jabalpur#2
PGCIL (Y)
26/10/2010 23:54 28/10/2010 16:30 A/T on R-B fault. Jumper got opened.
49 220kV TAPS
220kV TAPS-Bhilad
GETCO 26/10/10 14:02 26/10/10 14:24 Tripped on B ph Z-I.
50 400kV Satna 400kV Satna-
Bina#2 PGCIL (Y)
27/10/2010 16:43 27/10/2010 16:43 A/R on Y-N fault
51
400kV Gandhar
400kV Gandhar-Dehgam#1
PGCIL (Y)
11-02-2010
09:58 11-02-2010 10:24 A/R at Dehgam end and A/T at Gandhar (NTPC) end
52
400 KV Kasor
400 KV Kasor-SSP
GETCO (Y)
11-07-2010
14.06 11-07-2010 18.28 Kasor end: Remote trip receive, A/R lock out SSP end: O/V stage 1 & 2,
53 400kV Jabalpur
400kV Jabalpur-Itarsi#1
PGCIL (Y)
11-10-2010
11:22 11-10-2010 11:56 A/T on persisting fault
54
400 KV Kasor
400 KV Kasor-SSP
GETCO (Y)
11-11-2010
23:00 11-12-2010 8.35 Kasor end: Remote trip receive, A/R lock out SSP end: O/V stage 1 & 2,
55
400kV V’chal
400kV V’chal-Jabalpur#3
PGCIL (Y)
11-11-2010
04:26 11-11-2010 04:47 A/R at Jabalpur end and A/T at VSTPP (NTPC) end
56
400 KV Bhadravati
400 KV Bhadravati-Raipur-2
PGCIL (Y)
12/11/10 16:59 12/11/10 16:59 Line A/R Successful on B ph to E/F at both ends Dist-295 Km from Bhadrawati.
57 400kV Bina 400kV Bina-
Nagda#1 PGCIL (Y)
13/11/2010 13:42 13/11/2010 13:42 A/R on Y-N fault
58 400kV Satna 400kV Satna-
Bina#3 PGCIL (Y)
16/11/2010 04:04 16/11/2010 04:04 A/R on Y-N fault
59
400 KV Raipur
400 KV Raipur - Raigarh # 1
PGCIL (Y)
18/11/10 03:12 18/11/10 03:22 Line tripped due to operation of Over voltage Stage-1 at Raigarh.
60 765kV Agra 765kV Agra-
Gwalior#1 (400kV)
PGCIL (Y)
18/11/2010 02:57 18/11/2010 06:55 A/T on operation of OV stg-I at Gwalior end
61
400 KV Raipur
400 KV Raipur - Raigarh # 2
PGCIL (Y)
20/11/10 03:00 20/11/10 03:10 Line tripped on O/V at Raigarh & D/T received at Raipur.
62
HVDC Bhadrawati
HVDC POLE-1 at Bhadrawati
PGCIL 20/11/10 06:27 20/11/10 06:58 Pole tripped on pole control A.C over voltage alarm due to voltage disturbance in sourthen bus.
63
400 KV Kasor
400 KV Kasor -GPEC
GETCO (Y)
20/11/2010 20.32 20/11/2010 20.32 Kasor end: Y-Ph- G, Zone-1, dist. 39.6 kms. GPEC end: Y-Ph- G, Zone-1, dist. 42.1 kms. A/R successful at both ends.
64
400 KV Raipur
400 KV Raipur - Raigarh # 2
PGCIL (Y)
22/11/10 02:24 22/11/10 02:34 Line tripped on Over voltage at Raigarh,D/T received at Raipur.
65
400 KV Wardha
400 KV Wardha - Akola # 2
PGCIL (Y)
23/11/10 02:47 23/11/10 02:51 Line tripped on Over voltage at Akola,D/T received at Wardha.
66
400 KV Bhilai
400 KV Bhilai - Korba # 2
PGCIL (Y)
23/11/10 11:20 23/11/10 11:38 Line tripped due to relay mal-operation at NTPC,Korba end only but Line hanging from Bhilai end.
67
400kV Koradi
400kV Koradi-Akola
MSETCL (Y)
23/11/10 2:05 23/11/10 5:32 O/V stage-I trip at Akola end. L/O trip at Koradi end on receipt of DT from Akola.
68
400 KV Soja 400 KV Soja-Wanakbori
GETCO (Y)
24/11/10 3.53 24/11/10 4.53 Soja end: A/R Lock out Wanakbori end: O/V stage-1, A/R LO
69 400kV Satna 400kV Satna-
Bina#4 PGCIL (Y)
26/11/2010 02:21 26/11/2010 02:21 A/R on B-N fault
70 400kV Bina 400kV Bina-
Nagda#1 PGCIL (Y)
27/11/2010 15:40 27/11/2010 15:40 A/R on B-N fault
71 400kV Khaparkheda
400kV K'kheda-Chandrapur
MSETCL (Y)
29/11/10 4:15 29/11/10 12:16 Y-N fault. A/R attempted but went into L/O.
72
400kV Koradi
400kV Koradi-Bhusawal
MSETCL (Y)
29/11/10 4:15 29/11/10 4:21 Line tripped on U/V prot, meant for analog triggering. The tripping was simultaneous to tripping of 400kV K'Kheda-C'pur line. Analog triggerring for U/V of REL 521
disabled on Bhusawal & Akola lines at Koradi end. Matter referred to ABB.
73
400KV Korba
400KV Korba-Vindhyachal # 2
PGCIL (Y)
01/12/10 08:53 01/12/10 11:33 Line successfully Autoreclosed on B-E fault at 250.9 Km from Korba but A/R Unsuccessful (tripped) at V'Chal end due to R-B ph-ph fault..
74
400KV Ranchi
400KV Ranchi-Sipat # 2
PGCIL (Y)
01/12/10 18:18 01/12/10 19:56 Line tripped due to DC earth leakage at Sipat end only, attended the same.
75 400kV Sarni 400kV Sarni-
Seoni MPPTCL (Y)
12-03-2010
2:05 12-03-2010 5:00 Cph Bkr.pole disceipancy. Gr.A/B L/O.
76
220kV TAPS
220kV TAPS-Vapi
NPCIL 12-07-2010
6:54 12-08-2010 22:20 Tension Insulator(Si.Rubber Ins.) mechanical failure at Loc.No.834.
77 400kV Khandwa S/S
400/220kV, ICT#1
PGCIL 12-09-2010
08:20 17/12/10 01:08 A/T on failure of R phase Bushing of 400kV side
78 400KV Ranchi
400KV Ranchi-Sipat # 2
PGCIL (Y)
11/12/10 22:35 11/12/10 22:45 Line tripped on over voltage at Ranchi end .
79
400kV Bhilai
400kV Bhilai-Korba(W)
CSPTCL (Y)
14/12/10 0:13 14/12/10 1:06 Line tripped from Korba(W) end only at 00:13hrs and tripped at 00:33hrs from Bhilai end on receipt of Carrier Trip from Korba(W).
80
220kV TAPS
220kV TAPS-Boisar
NPCIL 15/12/10 13:40 15/12/10 14:14 Tripped in C-ph, Z-1 (F.Loc.6.5km, F.Current 8.838KA)
81 400KV Raigarh
400KV Raigarh-Rourkela # 2
PGCIL (Y)
20/12/10 02:25 20/12/10 02:35 Line tripped on O/V at Raigarh end
82 765KV Seoni
765KV Seoni-Wardha # 1
PGCIL (Y)
20/12/10 03:05 20/12/10 03:15 Line tripped on O/V at both ends
83 400KV Wardha
400KV Wardha-Akola # 1
PGCIL (Y)
20/12/10 03:05 20/12/10 03:15 Line tripped on O/V at Wardha
84
400KV Vapi 400KV Vapi-Boisar
PGCIL (Y)
20/12/10 11:58 20/12/10 11:58 Autoreclosed successfully at both sides on Y-E fault, F/L= 47.2km from Boisar end.
85
400KV Korba
400KV Korba-Bhilai # 1
PGCIL (Y)
25/12/10 10:10 25/12/10 10:10 Line autoreclosed successfully at both ends on R-E fault.F/L at a distance of 60.52Km from Bhilai end.
86
400kV V’chal
400kV V’chal-Satna#3
PGCIL (Y)
27/12/2010 10:45 27/12/2010 11:56 Line A/R at Satna end only but A/T at VSTPP (NTPC) end
87
400 KV Vadavi
400 KV Vadavi-Dehgam line no.2
GETCO (Y)
29/12/10 5.09 29/12/10 13.37 Line A/T & A/R successfully However tripped at Vadavi end: SOTF, Y-Ph. to G, Dist: 42.9 kms. Dehgam end: Y-Ph. to G, Zone-1, Dist 8.6 kms.
Annexure –4 Present status on recommendations pertaining to Protection of Inquiry Committee on grid disturbances of 25.02.2007 and 28.02.2007. Sr no
Recommendations
I
Decisions and Suggestions of PC for implementing the
recommendations II
Status
III
v) The simulation studies indicate that the distance protection scheme provided on some lines are under-reaching due to in-feed effect. Protection Committee of WRPC may look into this aspect and review the settings of 400 kV lines considering in-feed.
In 98th PCM it was agreed that Zone –III settings considering in-feed effect is to be arrived after due study and on case to case basis. It was suggested that each state should initiate studies starting with any one station in their system results of the study may be put up to Committee for further discussions. During 104th PCM Constituents were requested to carryout study for one of the 400kV S/S in their system and put up to committee for further review. MSETCL was requested to pursue with the protection review group to take up the issue for Padghe S/S.
Since PGCIL & MSETCL lines have multi-feed problem, a group from PGCIL, MSETCL, WRLDC & WRPC will study the problem & suggest solution. It was decided that a group comprising representatives from PGCIL WRTS-I & II, MSETCL & Load Dispatch, WRLDC POSOCO & WRPC be formed to decide & implement the settings on pilot basis.
vii) With the tripping of ± 500 kV Chandrapur-Padghe HVDC link, large quantum of power gets suddenly diverted to other alternative A.C. networks and usually results in tripping of a number of lines on power swings. The Committee recommends that with the tripping of the both poles of HVDC link, generation level at Chandrapur thermal power station of MSPGCL may be brought down automatically to prevent spread of the disturbance. WRPC may work out a suitable scheme in consultation with MSETCL
MAHAGENCO & MAHATRANSCO were requested to expedite action to formulate the scheme.
Committee requested MSETCL to carry out preliminary analytical studies for further deliberation. It was decided that a meeting be held among MSETCL, SLDC Kalwa, MAHAGENCO & WRPC to look into & formulate the scheme.