eastern regional power...

EASTERN REGIONAL POWER COMMITTEE

MINUTES OF 38TH PROTECTION SUB-COMMITTEE MEETING HELD AT ERPC,

KOLKATA ON 28.12.2015 (MONDAY) AT 11:00 HOURS

List of participants is enclosed at Annexure-A

PART – A

ITEM NO. A.1: Confirmation of minutes of 37th Protection sub-Committee Meeting held on 19th November, 2015 at ERPC, Kolkata.

The minutes of 37th Protection Sub-Committee meeting held on 19.11.15 circulated vide letter dated 01.12.15. No comments have been received from any constituent. The minutes of the above meeting may be confirmed. Deliberation in the meeting Members confirmed the minutes of 37th PCC meeting.

PART – B

ANALYSIS & DISCUSSION ON GRID INCIDENCES WHICH OCCURRED IN CTU/STU SYSTEMS DURING NOVEMBER, 2015. Item No B.1. Total power failure at 220kV Chandil S/s of JUSNL system on 06/11/15 at

19:37hrs At 19:29 hrs, 220kV Ranchi- Chandil S/c tripped from Chandil end only on operation of master trip relay and subsequently at 19:30 hrs, total power interruption occurred at Chandil S/s due to heavy sparking in earth pipe connector point of 220kV Chandil- Santaldih bay at Chandil end. Due to this approx. 140 MW load loss occurred at Chandil S/s including traction power of 50 MW at Rajkharswan, Goelkera, Kendposi, Chakardharpur, Golmuri and Manique. Following elements tripped:

Time (Hrs) Details of tripping Relay at local end Relay at remote end

19:29 hrs- 19:31 hrs (as per JUVNL report)

220 KV Chandil - Ranchi S/C

AT Chandil Master Trip Relay

At Ranchi Did Not Tripped

220 KV Chandil- Santaldih S/C

No information available for the said line except heavy fire on earth phase pipe connector point

220kV Chandil-Ramchandrapur S/c

Manually off from Chandil end

132 kV Chandil- Rajkharswan S/c

(as per JUVNL report)

132 kV Chandil -Adityapur – Rajkharswan S/c

Analysis of PMU plots: At 19:29 hrs- 19:31 hrs

• From the Jamshedpur & Ranchi PMU plot neither change in voltage nor rise in line current have been observed during the above-mentioned period.

At 19:36:31:840 hrs

Minutes of 38th PCC meeting 2

• From the Jamshedpur PMU plot 6kV Voltage dip in both Y-Ph & B-Ph have been observed at 19:36:31:840 hrs.

• 30 A rise in B-Ph line current of 400kV Jamshedpur –Maithon-I has been observed during the said period.

• Fault persistence time was approx. 80 ms. JUSNL may explain. Deliberation in the meeting JUSNL explained that

• 220 KV Chandil - Ranchi S/C tripped from Chandil end on operation of master trip relay. They could not retrieve the DR and EL as the distance relay installed at Chandil end was old relay (SEL 311C). JUSNL informed that there is no physical fault in the system, it was a maloperation of SEL 311C relay.

• Simultaneously, heavy sparking was observed in R-phase pipe connector point of 220 KV Chandil- Santaldih S/C isolator and the operator manually switched off the line.

• As a result, the power flow in 220kV Chandil-Ramchandrapur S/c has increased from 110 MW to 190 MW and 220kV Bus-bar coupler at 220kV Ramchandrapur was tripped on O/C protection.

• Due to tripping of 220KV Bus-bar coupler at 220kV Ramchandrapur, both 220KV buses became isolated with Chandil connected in main bus-I and ICT-II connected in main bus-II. 220KV ICT –I and 220KV Ramchandrapur-Joda were already under shutdown.

JUSNL informed that they have taken the following corrective actions after the tripping:

• Replaced the old relays in following lines with new Micom P442 relays:

SL NO

FEEDER NAME DATE OF COMMISIONING

OLD RELAY CHANGED

NEW RELAY TYPE

1 220KV CHANDIL-Ranchi (Chandil end) 07.11.15(11:08HRS) SEL 311C MICOM P442 2 220KV CHANDIL-STPS (Chandil end) 06.11.15(12:13HRS) SEL 311C MICOM P442 3 220KV CHANDIL-RCP (Chandil end) 08.11.15(09:34HRS) MICOM P430C MICOM P442 4 220KV RCP-CHANDIL (RCP end) 25.11.15 MICOM P430C MICOM P442

• Over current setting of Bus-Bar Coupler at 220kV Ramchandrapur & 220kV

Ramchandrapur -Chandil feeder has been reviewed as given below:

Sl no

Feeder Old setting New setting

1 220KV RCP-CHANDIL (RCP END) O/C-PSM-900mA TSM-500mS E/F-PSM-200mA TSM-200mS

O/C-PSM-900mA TSM-300mS E/F-PSM-200mA TSM-200mS

2 220KV BAR-COUPLER at 220kV RAMCHANDRAPUR

O/C-PSM-800mA TSM-500mS E/F-PSM-200mA TSM-200mS

O/C-PSM-1.2A TSM-500mS E/F-PSM-200mA TSM-200mS

• Proposal has been placed to their highest authority for changing the old panels of protection

system and CTs at 220kV Chandil and Ramchandrapur. ERLDC informed that JUSNL is not sending the tripping report. PCC advised JUSNL to send the tripping report as per the format enclosed at Annexure- B1 along with DR and EL for detail analysis of the tripping. JUSNL agreed.


Item No B.2. Total Power failure in part of North Bihar on 11/11/15 at 19:57hrs. As per primary information received from BSPTCL through telephonic conversation, both 132kV Madhepura- Supaul D/c lines were tripped at 19:57 hrs on overcurrent protection. Details of tripping are as follows:

Time (Hrs)

Details of tripping Relay at local end Relay at remote end

19:57 hrs

132kV Madhepura-Supaul- I & II All the mentioned line tripped on indication of O/C

protection, (As verbally informed by BSPTCL)

132kV Purnea(PG)- Purnea(BSPTCL)-I,II & III

132kV Purnea(PG) - Kishanganj S/C

Analysis of PMU plots: From the Binaguri & Patna PMU plot, no indication of the fault has been observed during the said period.

Due to non-availability of detail tripping report, DR and EL records from both BSPTCL and Powergrid, the exact sequence/reason of the tripping cannot be established. BSPTCL and Powergrid may explain. Deliberation in the meeting BSPTCL explained that

• There was no physical fault in the system. • Load in around Supoul was increased on Diwali festival, which resulted in over loading of

132kV Madhepura-Supaul- I & II. • 132kV Madhepura-Supaul- I & II tripped on O/C protection • As a result, 132kV Purnea(PG)- Purnea(BSPTCL)-I,II & III and 132kV Purnea(PG) -

Kishanganj S/C tripped on O/C protection


BSPTCL informed that they have taken the following corrective actions after the tripping:

• O/C protection settings of 132kV Madhepura-Supaul- I & II at Supoul end has been increased from 100% to 120% and CT setting at Madhepura end has been corrected to 400:1 (earlier 300:1).

On query, BSPTCL informed that Supaul end CT ratio is 300:1. PCC advised BSPTCL to replace 300:1 CTs with higher CT ratio for all 132kV lines in order to avoid the saturation of CT during faults and unnecessary restriction of power flow through the line. PCC enquired about future planning of their system to avoid such over loading of lines. BSPTCL informed that 220/132kV Kishanganj (new) GSS is under construction and expected to commission by May, 2016. This will provide power supply to 132kV Kishanganj and Forbesganj and 220kV Madhepura S/s. This arrangement will ensure continuous power supply to Nepal. BSPTCL also mentioned that Pandul and Madhubani are the huge load points and they are planning to LILO the existing 132kV Darbanga-Palpara D/C lines, one at Padoul and other at Madhubani. ERLDC informed that tripping report was not yet received from Powergrid ER-1. PCC took serious note of not submitting the tripping report by Powergrid ER-1 and non-representation in the meeting. Item No B.3. Total Power failure in part of North Bihar on 19/11/15 at 21:43 hrs. As per information received from BSPTCL through telephonic conversation, 132kV Madhepura- Supaul D/c line tripped at 21:43 Hrs, followed by 132kV Purnea (PG)- Kishanganj S/C and 132kV Purnea (PG)- Purnea(B) T/C.

Time (Hrs)


21:43 hrs

132kV Purnea(PG)- Purnea(B)-I,II & III

At Purnea(PG) directional O/C

At Purnea(B) Did Not Tripped

132kV Purnea(PG) - Kishanganj S/C At Purnea(PG) Tripped

(As informed by BSPTCL through telephonic

conversation)

At Kishanganj Did Not Tripped

132kV Madhepura- Supaul D/C (As informed by BSPTCL through telephonic conversation, both the line tripped )

From SCADA data recorded at ERLDC it is observed that coincident with tripping of 132kV Purnea(PG) – Purnea(B) T/C, power flow through 220kV New Purnea-Madhepura D/C also became zero. Power supply to Madhepura and Sonebarsa also failed. After tripping of all 132kV lines from Purnea(PGCIL & BSPTCL), load loss of around 486 MW occurred at Purnea, Naugachhia, Khagaria, Katihar, Saharsa, Madhepura, Sonebarsa, Supaul, Katiya, Forbesganj & Nepal areas. Minutes of 38th PCC meeting 5

Analysis of PMU plots: • From the Binaguri PMU plot 38kV voltage dip has been observed in B-Ph at 21:43:39:800 hrs. • Fault persistence time was approx. 80 ms.

Due to non-availability of detail tripping report from Powergrid, the exact sequence/reason of the tripping cannot be established. BSPTCL and Powergrid may explain. Deliberation in the meeting BSPTCL informed that

• The newly commissioned M/S Kanohar make100MVA ATR 3 tripped on REF without any fault in the system

• As a result, the load of ATR 3 (86 MW) was shifted to other two 100MVA transformers and got tripped on over current protection due to overload.

BSPTCL informed that manufacturer has been contacted and they have changed the wiring of REF protection. PCC advised BSPTCL to collect the details of changes made in REF protection wiring from the manufacturer. ERLDC informed that tripping report was not yet received from Powergrid ER-1. PCC could not conclude the tripping incidence due to non availability of tripping details of 132kV Purnea(PG)- Purnea(B)-I,II & III and 132kV Purnea(PG) - Kishanganj S/C from Powergrid ER-I. PCC took serious note of not submitting the tripping report by Powergrid ER-1 and non-representation in the meeting. Item No B.4. Total power failure at 220/132kV Biharshariff S/s of BSPTCL system & 220kV

Tenughat & Patratu S/S of JUSNL system on 23/11/15 at 13:11hrs At 13:11 hrs, power interruption occurred in BSPTCL & JUSNL systems due to bursting of Y-Ph CT of 132kV Biharshariff- Hatida Ckt –I at Biharshariff end. As reported by BSPTCL, due to bursting of the CT heavy flashover was observed in 132kV Biharshariff switchyard and for safety purpose all the 220 & 132kV feeders emanating from 220/132kV Biharshariff S/s were made manually off. After tripping of above mentioned lines in BSPTCL system, total power of Tenughat & Patratu (barring the local load of Patratu) was diverted through remaining 220kV PTPS – Hatia-I feeders in JUSNL which resulted in tripping of other elements from Tenughat, Hatia(old) & Patratu S/s. Details of tripping are as follows:

Time (Hrs)


132KV Biharshariff – Hatida-I

At Biharshariff O/C, E/F, Y-Ph, F.C- 3.84 KA,

master trip 86

At Hatida Did Not Trip

220kV Tenughat- Patratu S/c

At Tenughat Did Not Trip

At Patratu Overvoltage

220 kV Patratu-Hatia- I At Patratu At Hatia Minutes of 38th PCC meeting 6

13:11 Hrs

Tripped phase ABC, over current Did Not Trip 132kV Hatia(new)-

Namkun At Hatia

Dierctional overcurrent, 67Y , Trip Relay 86

At Namkun Did Not Trip

132kV Hatia(old)- Hatia(New)-I

At Hatia (old) Non-Directional Over current Protection 51B,Trip Relay 86

At Hatia (new) Did Not Trip

Tenughat U#1 &2 Tripped due to loss of evacuation path Patratu U # 10

400/220kV,315 MVA ICT-I,II & III at Biharshariff(PG)

(tripped from LV side on backup overcurrent protection) As informed by PGCIL through telephonic conversation

220KV Biharshariff - Fathua -I & II

Manually switched Off Due to heavy fire in 132kV Biharshariff switchyard

220KV Biharshariff -Begusarai –I & II 220KV Biharshariff –Tenughat 220/132kV , 150MVA ATR-I, II & III at Biharshariff 132kv Baripahari ckt-I & II 132KV Nalanda-Barhi 132KV Rajgir-Barhi ckt 132KV Ekangarsarai ckt 132KV sheikhpura ckt 132KV Nawada ckt

Analysis of PMU plots:

• From the Sasaram PMU plot 15kV voltage dip has been in Y-Ph at 13:11:17:660. • Fault persistence time was approx.740 ms.


Detailed Analysis of events: As per information received from BSPTCL & JUSNL, the event was initiated at 13:11 hrs, due to bursting of Y-Ph CT of 132kV Biharshariff- Hatida Ckt-I at Biharshariff end. PGCIL through telephonic conversation informed that, all the 400/220kV, 315 MVA ICTs at Biharshariff (PG) tripped from LV side. Since the fault was not cleared from 220/132kV Biharshariff end 315 MVA ICTs tripped from LV side of 400kV Biharshariff (PG) end. BSPTCL mentioned that, bursting of Y-Ph CT had caused major fire hazard in Biharshariff(BSPTCL) switchyard and as a safety measure all the 220kV & 132kV feeder emanating from 220/132kV Biharshariff S/s were made manually off one by one. After opening of the breaker of 220kV Tenughat- Biharshariff ckt at Biharshariff end, generation at Tenughat & Patratu was diverted through remaining 220kV Patratu- Hatia ckt-I (as ckt-II was under shutdown) and it had caused the tripping of the said ckt on operation of overcurrent protection from Patratu end. JUSNL in their report have mentioned that during the said period other 132kV lines emanating from Hatia (old) S/s such as Hatia (old)-Hatia (new) –I and Hatia (old)- Namkun S/c tripped on indication of overcurrent protection from Hatia (old) end. It is suspected that prior to tripping of above mentioned 132kV lines from Hatia (old) S/s, 2X150MVA, 220/132kV ATRs at Patratu had already tripped( as from the SCADA data, MW flow became zero) otherwise the said 132kV circuits shouldn’t have tripped from Hatia(old) S/s on operation of O/C protection. But neither tripping of 220/132kV ATR at Patratu nor 132kV Patratu- Hatia(Old) D/C have been reported by JUSNL. It is apprehended that after opening of 220kV Tenughat-Biharshariff S/C from Biharshariff and tripping of Tenughat units but prior to Patratu 220kV bus becoming dead, 220kV Tenughat- Patratu S/c tripped on overvoltage protection from Patratu end. After tripping of existing 220kV lines emanating from Patratu & Tenughat power stations, all the running unit of Patratu & Tenughat tripped due to loss of evacuation path and total generation loss of approx. 454 MW occurred in JUSNL system. Also due to non-availability of 220kV &132kV lines from Biharshariff S/s total load loss of approx. 320 MW occurred at Biharshariff & its surrounded areas. Discrepancies observed and Remedial Measures/Suggestions:

• Reason for not clearing the fault from 220/132kV ATRs at 220kV Biharshariff end. • After tripping of 220kV PTPS-Hatia(New) -1, the entire power of this line should get shifted

to 132kV PTPS-Hatia D/C. No tripping of this line has been reported by JUSNL. However, as the loads fed from Hatia(Old) are radial and therefore fixed in nature (viz. Namkum, Traction, Lohardaga, Latehar etc.) the reason for tripping of 132kV lines from Hatia(Old) is not understood.

• As per SCADA data, it seems that during the said period 220/132kV ATR at Patratu tripped, as the MW flow became zero. But no such type of tripping of the said ATR has been reported by JUSNL. Thus JUSNL may check and explain whether 220/132kV ATR at Patratu tripped. JUSNL have also not mentioned whether any load loss actually occurred in their system.

Reports received from BSPTCL and JUSNL. Tripping details are not yet received from Powergrid. BSPTCL, JUSNL and Powergrid may explain.


Deliberation in the meeting BSPTCL and JUSNL explained that

• There was a fault in 132kV Biharshariff- Hatida Ckt –I due to bursting of Y-Ph CT at Biharshariff end. Biharshariff end identified the fault and initiated tripping of the line.

• In the mean time, heavy flashover was observed in 132kV Biharshariff switchyard and all the 220 & 132kV feeders emanating from 220/132kV Biharshariff S/s were manually switched off for the safety purpose.

• Since 220kV Patratu-Hatia line II was under shutdown, the total power of Tenughat & Patratu generators (barring the local load of Patratu) was diverted through remaining 220kV PTPS – Hatia line-I, which resulted in tripping of other elements from Tenughat, Hatia(old) & Patratu S/s.

JUSNL failed explain the tripping of 220kV lines from Patratu. PCC advised SLDC, Jharkhand to coordinate and collect the tripping details from Patratu TPS in future for proper analysis of the tripping incidences. PCC advised JUSNL to restrict the generation of TVNL and Patratu TPS during any 132kV and above line shutdown to maintain the reliability of the JUSNL system in case of N-1 contingency. ERLDC informed that tripping report was not yet received from Powergrid ER-1. PCC took serious note of not submitting the tripping report by Powergrid ER-1 and non-representation in the meeting. Item No B.5. Total power failure at 220kV Biharshariff S/s of BSPTCL system on 28/11/15 at

17:32hrs. At 17:32 hrs, total power failed at 220kV Biharshariff S/s due to Snapping of R-Ph jumper of 315 MVA ICT-III bay (220kV side) connecting 220kV main Bus-II & isolator near to female contact and subsequently all the 315MVA ICTs at Biharshariff(PG) tripped from HV (400kV) side. At the same time 220kV Tenughat-Biharshariff S/c also tripped from Tenughat end. Details of tripping are as follows:

Time (Hrs)


17:32 Hrs

400/220kV,315 MVA ICT-I,II & III at

Biharshariff(PG)

HV side B/up O/C

(informed by PGCIL through telephonic conversation)

LV side Master Trip

220/132kV , 150MVA ATR-I, & II at

Biharshariff(BSPTCL)

HV side E/F

LV side Master Trip

220KV Biharshariff –Tenughat

At Biharshariff Did Not Trip

(manually off)

At Tenughat DP, Z-II, FD- 176 KM


• From the Biharshariff PMU, data 70kV voltage dip has been observed in R-Ph voltage at 17:32:33:560.


• 300 A rise in R-Ph line current of 400kV Biharshariff- Sasaram-I has been observed during the said period.

• Fault persistence time was approx.440 ms.

Detailed Analysis of events:

As per information received from BSPTCL, the event was initiated at 17:32 hrs, due to snapping of R-Ph Jumper of 315 MVA ICT-III bay (220kV side) connecting 220kV Main Bus- II & isolator near to female contact.

Since fault was near to bus-II, all the 400/220kV, 315 MVA ICTs at Biharshariff (PG) tripped from

HV side on operation of back up Overcurrent protection and 220/132kV, 150 MVA ATR-I & II tripped from both HV & LV side on operation of E/f & master trip relay respectively. 220kV Tenughat- Biharshariff which was connected to bus-II also tripped from Tenughat end on indication of DP, Z-II.

Moreover, BSPTCL in their report have also mentioned that at 17:32 hrs, major fire hazard with

sound was observed in 220kV side switchyard area of Biharshariff (BSPTCL) GSS and as a safety measure all the remaining 220kV & 132kV CBs were made manually off and Main Bus- II was made dead and isolated. Thereafter following feeders were charged through the Main Bus-I

• 315 MVA ICT –I & II • 150 MVA ATR-III • 220kV TTPS- Biharshariff S/c • 220kV Biharshariff- Begusarai -I

Due to above mentioned tripping of lines from 220/132kV Biharshariff S/s total load loss of approx. 450 MW occurred at Biharshariff & its surrounded areas.


Discrepancies observed:

• Since fault was near to the 220kV bus-II, all 220kV lines connected to bus-II (if any) should pickup the fault in zone 2 from remote end. BSPTCL may place the details. Begusarai end relay fails to identify the fault in 220kV Biharshariff- Begusarai-I on 08-10-2015.

• 220/132kV, 150 MVA ATR-I & II connected to Main Bus-II tripped from both HV & LV side on operation of E/f & master trip relay respectively. HV side should not trip as the fault was in reverse direction for all the ATRs.

Tripping report received from BSPTCL. Tripping details are not yet received from Powergrid. BSPTCL and Powergrid may explain. Deliberation in the meeting BSPTCL explained that

• Fault was in R-Ph jumper of 315 MVA ICT-III bay (220kV side) connecting isolator female contact at Biharshariff.

• Fault was isolated from 315 MVA, 400/220kV, ICT-I,II & III and 150MVA, 220/132kV , ATR-I, & II.

• Since the fault was near to 220kV bus-II at Biharshariff S/s and bus bar protection was out of service, 220KV Biharshariff –Tenughat was tripped from Tenughat end on zone 2 distance protection.

• Other 220 kV lines were not tripped from remote end, as the lines are connected to radial loads.

PCC felt that the tripping was in order. BSPTCL informed that the isolator connected to 315 MVA ICT-III bay and 220kV main Bus-II is not order and it is belongs to Powergrid. PCC advised Powergrid to take necessary action. ERLDC informed that tripping report was not yet received from Powergrid ER-1. PCC took serious note of not submitting the tripping report by Powergrid ER-1 and non-representation in the meeting. Item No B.6. Total Power failure in 220kV Malda & Dhalkhola of WBSETCL system on 20/11/15

at 20:55hrs.


Network configuration before the disturbance:

• 400 KV Farakka-Malda –II was under continuous shutdown prior to the incident. • 400 KV Malda –Purnea –II was opened prior to incident to control the over-loading of 400

KV Farakka – Malda – I. (1) Tripping of 400 kV Farakka – Malda- I at 19:34 Hrs.

400kV Farakka-Malda –I tripped at 19:36 hrs from Malda end only due to DT received at Malda end. Details from Farakka end: As per information received from FARAKKA PLCC Counter increased as below Malda 1 Channel 1 Tx -B advanced from 17 To 19. Malda 1 Channel 2 Tx -A advanced from 17 To 19. This may be due to mal-operation of PLCC. Before tripping of Farakka –Malda –I ,flow in Farakka – Malda –II was approx 580 MW , as the 400 KV Farakka – Malda circuit –I tripped flow in 400 KV Purnea – Malda –I got reverse from Purnea to Malda and the flow was approx 180 MW. Network configuration after 19:34 Hrs and flow pattern

(2) Tripping of 400 kV Malda-Purnea – I at 20:54 Hrs At 20:54 Hrs to increase the redundancy of network ,charging attempt of 400 KV Malda – Purnea –II has taken from Malda end and following that 400 KV Malda - Purnea –I tripped on stage –I overvoltage protection (110% ,with 5 sec time delay) as the time delay for 400 KV Malda - Purnea –II was 7 second , 400 KV Malda - Purnea –I tripped before 400 KV Malda - Purnea –II . DT was received at Purnea end and 400 KV Malda - Purnea –I tripped from Purnea end. (3) Tripping of 220 kV Purnea (New) - Purnea (OLD) – I, II at 20:54 Hrs After tripping of 400kV Malda- Purnea-I Malda s/s got isolated from 400 KV network and load of Malda and Dalkhola was shifted to Purnea and Siliguri , resulted in overloading of 220 kV Purnea-Purnea I & II (800/1 ,100 %,Flow approx. -270 MW) and both the lines got tripped instantaneously. (4) Tripping of 220 kV Bus coupler at Dalkhola 20:54 Hrs As the 220 KV Purnea(new) – Purnea(old) , got tripped , Malda and Purnea, Dalkhola load was fed from 220 KV Binaguri – Siliguri – Dalkhola and Dalkhola Bus Coupler tripped on Overcurrent Minutes of 38th PCC meeting 12

protection with the setting (800/1 , 75% , Flow approx.- 220-230 MW) and hence complete load loss at Malda and Dalkhola was occurred 400/220 KV ICT III, V and 220/132 KV ICT I, II, IV. 220 KV MALDA – DALKHOLA I, II and 220 KV DALKHOLA – DALKHOLA (WB). 132 KV MALDA - MALDA were hand tripped. Tripping details:

Time (Hrs)


19:34 Hrs

400 KV FARAKKA – MALDA -I At Farakka(PG) MALDA 1 CHANNEL 1 TX -B ADVANCED FROM 17 TO 19

At Malda(B) DT received

20:54 Hrs

400 KV MALDA – PURNEA -I

At MALDA(PG) Stage –I , Overvoltage

protection

At Purnea DT received

20:54

Hrs 220 KV PURNEA – PURNEA –I &

II

Back up over current

20:54 hrs

220 KV BUS COUPLER Overcurrent Protection (800/1 at 75%)

Analysis of PMU plots: There is no significant voltage dip observed at the time of tripping. Thus indicating no physical fault in 400kV Malda-Farakka ckt-1 Powergrid and NTPC may explain the following:

i) Reason for sending DT from Farakka to Malda. ii) As per PSSE study maximum 4 to 5 Kv voltage rise was observed while charging the line

(Malda-Purnea II) from Malda end and as per SCADA data pre-charging voltage at Malda was 417 KV. Powergrid may explain the reason for sudden rise of voltage at Malda up to 438 kV.

Deliberation in the meeting Powergrid explained that 220V DC at Farakka S/s is +ve grounded and creating unbalance in DC supply during switching operation. As a result, PLCC system at Farakka end is sending DT without any fault in the line. PCC felt that even with any unbalance in 220V DC system, the PLCC system should not maloperate and advised Powergrid to pursue the issue with manufacturer to resolve the problem. PCC also advised NTPC Farakka to check 220V DC system and rectify the problem. Regarding tripping of 400kV Malda-Purnea line I & II on overvoltage, Powergrid explained that maintenance of line reactor is going on at the time of incidence and the line was charged without line reactor. This has caused overvoltage at 400kV Malda and tripped both the lines. Minutes of 38th PCC meeting 13

Item No B.7. Tripping incidences in the month of November, 2015 Other tripping incidences occurred in the month of Novemebr, 2015 which needs explanation from constituents of either of the end is given at Annexure- B.7. Members may discuss. Deliberation in the meeting Members explained the tripping incidence. Updated status is enclosed at Annexure- B.7.

PART- C

FOLLOW-UP OF DECISIONS OF THE PREVIOUS PROTECTION SUB-COMMITTEE MEETING(S)

(The status on the follow up actions is to be furnished by respective constituents) ITEM NO. C.1: Protection Committee visit to BSPTCL and JUSNL Sub-stations In view of repeated uncoordinated trippings in BSPTCL and JUSNL systems, 31st TCC/ERPC formed a committee of following protection engineers to review the situation:

• Shri Sabyasachi Roy, ACE, WBSETCL, • Shri L Nayak, GM, OPTCL • Shri Jayanta Datta, SE, DVC • Shri Surajit Bannerjee Asst GM, ERLDC, • Shri Jiten Das, Asst GM, PGCIL • Shri S. B. Prasad, ESE, BSPTCL • Shri Vidyasagar Singh, ESE, JUSNL

PCC needs the following information in respect of Chandil, Ramchandrapur, Adityapur and adjoining substations in Jharkhand and New Purnea, Madhepura, Biharshariff and adjoining substations in Bihar.

1. SLD of all the affected and surround Sub-station (with CT location) 2. Year of manufacture of all equipments 3. Comprehensive CT details along with name plate (with connected/adopted ratio ) 4. VT details 5. Fault level- 3-phase as well as 1-phase (line length, conductor details and

Transformer details for computing fault level) 6. Transformer detail (Rating, impedance) 7. Availability of Auto-Reclosure feature 8. Availability of carrier protection 9. Availability of Bus- differential and LBB Protection 10. Junction Box (JB) details 11. Cable details used for CT connections (Cross section/core of cable, Junction Box

(JB) details & length of cable between JB & control panel) 12. Grid earthing resistance (With latest test report) 13. Breaker details (operating time) 14. CT/PT earthing details 15. Relay details (Relay type, model, settings, manufacturing, basis of settings) 16. Scheme adopted for protection settings for lines and transformers


17. DC system details with charger and battery PCC requested JUSNL and BSPTCL to furnish the above listed details latest by 30.11.2015. Further, PCC decided to convene a special meeting of Protection Team tentatively on 8th December, 2015 at ERPC, Kolkata and advised JUSNL to attend the meeting with all requisite information. Accordingly, special meeting was held on 8th December, 2015 wherein BSPTCL and JUSNL updated the status enclosed at Annexure-C1. BSPTCL and JUSNL advised to submit the pending details latest by 23.12.15 so that the issue could be discussed again on next PCC meeting scheduled to be held on 28.12.15. BSPTCL and JUSNL may update. Members may discuss. Deliberation in the meeting BSPTCL and JUSNL have submitted the details. The updated status is enclosed at Annexure-C1. ITEM NO. C.2: Repeated Disturbances at 220kV Chandil S/s of JUSNL System. 1. Total power failure at 220kV Chandil S/s of JUSNL system on 01/10/15 at 10:50hrs In 37th PCC, JUSNL explained with the given diagram that--- The above tripping occurred due to B-Ø conductor snapping between location no 2 & 3 of

132kV Adityapur – Ushamartin circuit-I. Though the 132kV Adityapur – Ushamartin circuit-I tripped from both the end, the fault got

extended due to delayed tripping/clearance. Subsequently, the following elements tripped:

At Adityapur GSS:

a) 132 KV Adityapur – Ushamartin circuit –I tripped both end. b) 132 KV Adityapur – Ushamartin circuit –II tripped at Adityapur end. c) 132/33Kv 50 MVA Transformer I & II tripped.

At Ramchandrapur GSS:

a) 132KV Ramchandrapur-Adityapur circuit-1 tripped at Ramchandrapur end. b) 132 KV Ramchandra-Adiyapur circuit-2 tripped at Adityapur end.

At Chandil GSS:

a) 220KV Chandil –STPS T/L Tripped at chandil end. b) 132kv Chandil-Adityapur Tripped at Chandil end. c) 220/132kv 100MVA transformer I, II, III &IV all are triped.


The details of relay indications as furnished by JUSNL are as follows:

Sl.No. Name of Line Local end relay

Remote End relay

Remarks

1. 220kV Chandil- STPS T/L 86,95/86

Not tripped

Chandil end- SEL 311C STPS-P442

2. 220kV Chandil- Ramchandrapur

Normal Normal Chandil end- Micom P430C RCP end-P430C

3. 220KV Chandil-PGCIL Ranchi.

Normal Normal Chandil-SEL 311C

4 132KV Chandil-Adiyapur. Tripping relay 186

Not tripped Chandil-P430C Adpur-P441


5 100MVA, 220/132 KvTr.I at Chandil

B Ø , O/C (LV side trip)

6 100MVA, 220/132 KvTr.II at Chandil

B Ø , O/C (Both side trip)

7 100MVA, 220/132 KvTr.III at Chandil

B Ø , O/C (LV side trip)

8 100MVA , 220/132 KvTr.IV at Chandil

Master trip relay 86HV, Diff.operated LV-O/C (Both side trip)

5 132KV Ramchandrapur-AdityapurCkt-I

12km,Z-III Not tripped RCP- P442 Adpur-P442

6 132KV Ramchandrapur-AdityapurCkt-II

Not tripped O/C & E/F RCP-P442 Adpur-P442

7 132kv Adityapur-Ushamartinckt.- I

86,O/C,E/F,A/R relay lock out

O/C & E/F Fault this line BØ

Adpur-Eusion Reyrolle UML- Eusion Reyrolle

8 132kv Adityapur-Ushamartinckt.-II

O/C & E/F Not tripped Adpur-P441 UML-P441

9

50 MVA,132/33Kv Tr.no - I at Adpur

O/C,86 (HV & LV both side triped)

10 50 MVA, 132/33 Kv Tr.no - II at Adpur

O/C, 86 (HV & LV both side triped)

However, JUSNL failed to explain the tripping sequence & exact cause for un-coordinated trippings in proper manner and also the protection available for each element involved in the said disturbance. Regarding submission of DR/EL, JUSNL informed that the DR of the relays could not be downloaded as the relays were old and interfacing software is also not available with them. It was further informed that the old relays of Chandil S/s have been replaced with new relays. After detailed deliberation, PCC felt that JUSNL should carry out the detailed analysis for such un-coordinated trippings (element-wise) and place the report along with DR/EL inputs. JUSNL may place the report. Deliberation in the meeting PCC advised JUSNL to submit the report at the earliest.

2. Total power failure at 220kV Chandil S/s of JUSNL system on 21/10/15 at 00:15hrs Total power failed at 220kV Chandil S/s at 00:15 hrs, due to bursting of R-Ph CT of 220/132kV ATR-I at Chandil on 132kV side. The following elements were tripped: Time (Hrs)


220 KV Chandil -Santaldih S/C

AT Chandil Did not Trip

At Santaldih R-Ph, O/C, E/F

220 KV Chandil -Ranchi S/C


At Ranchi NA

220 KV Chandil –Ramchandrapur S/C


At Ramchandrapur E/f , O/C, Tripping relay


00:15 hrs

VAJ 132kV Ramchandrapur- Adityapur--I

At Ramchandrapur Power Swing, E/F, O/C, Tripping relay type VAJ

At Adityapur Did not Trip

132kV Ramchandrapur- Adityapur--II

At Ramchandrapur Did not Trip

At Adityapur E/f , O/C

132 KV Chandil – Adityapur S/C


At Adityapur E/f , O/C

132 KV Chandil – Rajkharswan S/C


AT Rajkharswan O/C

220/132kV , 100 MVA ATR-I

At HV E/F

At LV E/F, O/C

220/132kV , 100 MVA ATR-II

At HV E/F

At LV O/C

220/132kV , 100 MVA ATR-IV

At HV Did not Trip

At LV E/F, Master trip


• An observation of PMU plot of Ranchi Shows, there was a 8kV dip in R-Ph voltage and 6 kV dip in Y phase voltage during the incident.

• 70 A rise in R-Ph line current of 400kV Ranchi- Maithon has been observed during the said period.

• Fault persistence time was approx. 540 ms. Detailed analysis: It is suspected that there was a delayed opening of the breaker either at HV or LV side for ATR-I and it caused the tripping of other elements. Due to above mentioned tripping approx. 320 MW load loss occurred at Chandil & their surrounded area including traction loss of 50 MW at Rajkharswan, Goelkera, Kendposi, Chakardharpur, Golmuri, and Manique. JUSNL may explain the following:

• Any delayed operation of CB of 220/132kV ATR-I. • Tripping of 132kV Ramchandrapur- Adityapur—II from Adityapur on E/F, O/C

In 37th PCC, JUSNL informed that--- There was a fault at 220kV Chandil S/s due to bursting of R-Ph CT of 220/132 kV ATR-I on

132kV side. Due to delayed clearance of fault by ATR-I the two other 220/132 kV ATRs got tripped at

Chandil S/s. 220 kV as well as 132 kV feeders of Chandil and other 132 kV feeders also got tripped.

However, JUSNL failed to explain the tripping sequence & exact cause for un-coordinated trippings in proper manner and also the protection available for each element involved in the said disturbance. Regarding submission of DR/EL, JUSNL informed that the DR of the relays could not be downloaded as the relays were old and interfacing software is also not available. It was further informed that the old relays of Chandil S/s have been replaced with new relays.


After detailed deliberation, PCC felt that JUSNL should carry out the detailed analysis for such un-coordinated trippings (element-wise) and place the report along with DR/EL inputs. JUSNL may place the report. Deliberation in the meeting PCC advised JUSNL to submit the report at the earliest. ITEM NO. C.3: Disturbance at 220kV Ramchandrapur S/s on 20/10/15 at 05:38hrs At 05:38 hrs, 400/220KV, 315 MVA ICT-I & II tripped at Ramchandrapur due to busting of R-phase CT of 220KV Ramchandrapur-Chandil line at Ramchandrapur end. The Following lines tripped:

Time (Hrs)


05:36 hrs

220 KV Ramchandrapur -Chandil S/C

At Ramchandrapur Zone-III

At Chandil Zone-III, Master trip relay

220kV Ramchandrapur- Joda S/c

At Ramchandrapur NA

At Joda NA

400/220kV ICT-I at Jamshedpur

At Jamshedpur O/c

At Ramchandrapur Master Trip

400/220kV ICT- II at Jamshedpur

At Jamshedpur Back up O/c, R-ph

At Ramchandrapur Master Trip

132kV Chandil- Adityapur

At Chandil Trip relay 186

At Adityapur Did Not Trip

132kV Chandil- Rajkharswan S/c

At Chandil Back up E/F, O/C

At Rajkharswan Did Not Trip

132kV Ramchandrapur- Adityapur-I

At Ramchandrapur Did Not Trip

At Adityapur E/F, O/C

132kV Ramchandrapur- Adityapur-II

At Ramchandrapur Did Not Trip

At Adityapur E/F, O/C

220/132kV , 150 MVA ATR-I at RCP

O/C


• An observation of PMU plot of Jamshedpur Shows, there was a 50kV dip in R-Ph voltage during the incident.

• 540 A rise in R-Ph line current of 400kV Jamshedpur- Chaibasa has been observed during the said period.

• Fault persistence time was approx. 40 ms. Detailed analysis: Fault was in 220KV Ramchandrapur-Chandil line close to Ramchandrapur end. Due delayed fault clearance from Ramchandrapur end, 400/220kV ICTs at Jamshedpur, 220/132kV , 150 MVA ATR-I at RCP and 132kV Ramchandrapur- Adityapur-I & II got tripped.


JUSNL may explain the following: Tripping of 220 KV Ramchandrapur -Chandil S/C line from both ends on zone 3 distance

protection Tripping details of 220kV Ramchandrapur- Joda S/c Tripping of 132kV Chandil- Adityapur and 132kV Chandil- Rajkharswan S/c

In 37th PCC, JUSNL informed that--- There was a fault at 220kV Ramchandrapur S/S due to bursting of R-phase CT of 220kV

Ramchandrapur-Chandil line. Due to delayed fault clearance from Ramchandrapur end, 400/220kV ICTs at Jamshedpur,

220/132kV , 150 MVA ATR-I at Ramchandrapur and 132kV Ramchandrapur- Adityapur-I & II got tripped.

However, JUSNL failed to explain the tripping sequence & exact cause for un-coordinated trippings in proper manner and also the protection available for each element involved in the said disturbance. Regarding submission of DR/EL, JUSNL informed that the DR of the relays could not be downloaded as the relays were old and interfacing software is also not available. After detailed deliberation, PCC felt that JUSNL should carry out the detailed analysis for such un-coordinated trippings (element-wise) and place the report along with DR/EL inputs. JUSNL may place the report. Deliberation in the meeting PCC advised JUSNL to submit the report at the earliest. ITEM NO. C.4: Disturbance at 220 kV Biharshariff (BSPTCL) S/s on 08/10/15 at 08:29hrs

At 08:30 hrs, total power interruption occurred at Biharshariff (BSPTCL) 220/132/33kV S/s due to B-N fault on 220kV Biharshariff- Begusarai-I and subsequent tripping of 220kV Biharshariff- Begusarai-II along with 400/220kV,315 MVA ICT-I,II & III at Biharshariff (PGCIL) on operation of E/F & back up overcurrent protection respectively. The following elements were tripped:


Time (Hrs)


08:30 hrs

400/220kV , 315 MVA ICT-I Tripped on Back up O/C from HV side (informed by PGCIL)

ICT -1 - 86T, ICT-2 86T, ICT-3 - 86A

(informed by BSPTCL)

400/220kV , 315 MVA ICT-II

400/220kV , 315 MVA ICT-III

220kV Biharshariff- Begusarai-I At Biharshariff trip phase abc, zone Z1,

fault location XY 60.48KM, trip relay 86

At Begusarai NA

220kV Biharshariff- Begusarai-II At Biharshariff 86A1, 86A2, 130 EF CONTACT MULTI RELAY,86B1,B2

230CD CONTACT MULTIRELAY

At Begusarai NA


• An observation of Biharshariff PMU plots (enclosed) shows 15kV voltage dip in B-Ø at around 08:30:03 hrs.

• 45 A rise in B-Ph line current of 400kV Biharshariff- Ballia-I has been observed during the said period.

• Fault persisted for 940 ms. Detailed Analysis: As per the relay indications received from BSPTCL, it appears that Begusarai end failed to clear the fault in 220kV Biharshariff -Begusarai ckt- I and the fault was being fed through other 220kV lines such as Biharshariff- Begusarai Ckt-II. This resulted in tripping of 220kV Biharshariff- Begusarai ckt-II along with all the 315 MVA ICTs at Biharshariff on earth fault & backup overcurrent protection respectively from Biharshariff end. Thus after tripping of both 220kV Ckt along with all 315MVA ICTs at Biharshariff approx. 350 MW load loss occurred at 220/132/33KV Biharshariff (BSPTCL) GSS.

BSPTCL and Powergrid may explain the following:

iii) Relay flags/CB operation at Begusarai end for both Ckt-I&II. iv) Uncoordinated tripping of 220kV Biharshariff- Begusarai Ckt-II from Biharshariff end and

tripping of all 315 MVA ICTs at 400kV Biharshariff.

In 37th PCC, BSPTCL informed that--- There was a B-N fault in 220kV Biharshariff -Begusarai ckt- I line. Due to non clearance of fault from Begusarai end, 220kV Biharshariff -Begusarai ckt-II & all

400/220kV ICTs at Biharshariff got tripped. Remedial measures initiated at Begusarai end and relay settings are being reviewed. Same type of disturbance was occurred on 14.11.2015 and the 400/220 kV ICTs were not

disturbed on this occasion.

However, BSPTCL failed to explain the exact cause for un-coordinated trippings in proper manner


and also the remedial measures adopted at Begusarai end. Regarding submission of DR/EL, BSPTCL informed that their interfacing software has been corrupted; the same is being rectified. After the rectification of interfacing software the DR/EL will be furnished. After detailed deliberation, PCC felt that BSPTCL should carry out the detailed analysis for such un-coordinated trippings (element-wise) and place the report along with DR/EL inputs. Further, PCC advised BSPTCL to expedite for carrier protection for 220 kV Biharshariff –Begusarai D/C line as it is an important 220 kV line of BSPTCL system. BSPTCL may place the report. Deliberation in the meeting PCC advised BSPTCL to submit the report at the earliest. ITEM NO. C.5: Total Power failure in part of North Bihar on 10/10/15 at 17:46hrs At 17:46 hrs, 220kV Purnea- Madhepura line-I & II tripped. Subsequently, the following elements got tripped on directional over current protection:

1. 132 KV Purnea(Bihar) – Purnea(PG) –T/C , 2. 132 KV Purnea-Kishenganj

Power flow to Nepal got interrupted. Due to non-availability of detail tripping report along with DR and EL records from both BSPTCL and PGCIL, the exact sequence/reason of the above tripping cannot be established. In 37th PCC, BSPTCL informed that--- 220kV Purnea- Madhepura line got tripped at Purnea end due to transient fault. This led to overload tripping of 132 KV Purnea(Bihar) – Purnea(PG) –T/C and 132 KV Purnea-

Kishenganj line.

BSPTCL informed that the 220 kV Purnea end is under Purnea (PG) sub-station, so the DR/EL details should be furnished by Powergrid. After detail deliberation, PCC concluded that the as BSPTCL is the owner of 220 kV bays of 220kV Purnea- Madhepura D/c line at Purnea (PG), BSPTCL should collect the DR/EL data from relays at Purnea (PG) in co-ordination with Powergrid. Further, PCC felt that the commissioning of inter-trip facility/ carrier protection for 220kV Purnea- Madhepura line should be expedited by BSPTCL. After detailed deliberation, PCC felt that BSPTCL should carry out the detailed analysis for such un-coordinated trippings (element-wise) and place the report along with DR/EL inputs. BSPTCL may place the report. Deliberation in the meeting BSPTCL submitted a report and explained that:

• Frequent tripping of 220kV Purnea-Madhepura line was due to transient fault. Line patrolling was carried out and line has been made clear. There was no tripping after September, 2015.


• Line patrolling was also done for 132kV Purena-Forbesganj line. • 220/132kV Kishanganj (new) GSS is under construction and expected to commission by

May, 2016. This will provide power supply to 132kV Kishanganj and Forbesganj and 220kV Madhepura S/s. This arrangement will ensure continuous power supply to Nepal.

PCC noted and advised BSPTCL to commission the inter-trip facility/ carrier protection for 220kV Purnea- Madhepura line. ITEM NO. C.6: Total Power failure at 400/220kV Rangpo S/s on 17/10/15 at 10:45hrs In 37th PCC, Powergrid informed that--- The tripping of 400 kV Teesta –Rangpo was due to mal-operation of SCADA at Rangpo S/s. The new 400 kV bay for 400 kV Teesta-III –Rangpo was under construction and the SCADA

engineers were working. Unknowingly, the Auto- sequencing feature of SCADA was under ON condition. During SAS upgradation work the Auto- sequencing feature operated the breaker and isolator

of new 400 kV bay. This led to grounding of Y-phase as it was hanging near to gantry and converted into a Bus fault. This tripped all the elements connected to 400 kV Rangpo Bus.

PCC took on adverse note mal-operation due to negligence during construction activities and advised Powergrid to ensure the compliance of all safety measures before carrying out any activities in online SAS system. PCC felt that for Double Main Bus system at 400 kV Rangpo S/s, the bus-coupler should have operated and elements of other bus should not have tripped. Further, DT signal from Rangpo S/s should have been sent to remote end. Powergrid responded that during the same time the Bus PT was under checking as per normal practice and for voltage selection both the isolators of Bus-coupler was in closed condition so bus-coupler did not opened. Regarding DT signal, Powergrid informed that they will check the scheme and revert back. PCC also felt that the tripping of 400 kV Teesta-Rangpo D/C line in zone-1 from Teesta end is not in order and advised NHPC to review the zone settings in co-ordination with Powergrid. Further, PCC seriously noted the tripping of 220 kV feeders from Jorthang HEP and advised JLHEP to review the protection settings at 220 kV Jorthang end. No representative of JLHEP was present in the meeting. On enquiry, ERLDC informed that before synchronisation of JLHEP, they have furnished the recommended settings however the adopted settings are yet to be received from JLHEP. Powergrid and NHPC may update. Deliberation in the meeting Powergrid informed that they have received the settings from Teesta end and forwarded to their corporate office for review. ERLDC informed that the adopted settings are yet to be received from JLHEP.


ITEM NO. C.7: Oscillations during de-synchronization of Teesta-V units. ERLDC vide letter dated 4th November, 2015 informed that repeated oscillations having oscillation frequency 0.06Hz and 0.5kV voltage amplitude observed during de-synchronization of Teesta units. The oscillations are persisting up to 4 minutes. Details are as follows: On 01-11-2015, the oscillations started at 20:27hrs and lasted upto 20:32 hrs while

desynchronizing unit#2 of Teesta-V. On 02-11-2015, the oscillations observed from 20:30hrs to 20:34hrs and from 21:58hrs to

22:02hrs at Binaguri while desynchronizing Teesta-V units. On 03-11-2015, the oscillations observed from 20:30hrs to 20:34hrs and from 21:58hrs to

22:02hrs at Binaguri while desynchronizing Teesta-V units. In 37th PCC, ERLDC explained the oscillations as observed during the de-synchronization of Teesta units with the help of PMU plots for the dates mentioned above. NHPC clarified that usually Teesta units are de-synchronised by reducing the load in automatic mode and finally the Circuit Breaker of the machine gets opened at 5 MW load. But, when the oscillations were observed and come into the view of NHPC, Teesta the de-synchronisation procedure was modified and now the oscillations has been stopped. The modified synchronization procedure involves reduction of load manually with opening of the Circuit Breaker of the machine at 10 MW load. PCC felt that the oscillations might have generated due to change in the adjoining system (addition of Jorthang units) and advised ERLDC and NHPC to check the earlier records if there was any case of oscillations prior to synchronization of Jorthang units. ERLDC and NHPC may update. Deliberation in the meeting Issue was discussed in 116th OCC Meeting held on 23-12-2015, wherein NHPC explained that the automatic PLC sequence & measurement system is responding with some time gap of around 4-5 seconds delay. This is causing oscillation in grid voltage. After detailed study, the pulse width of PLC has been modified and no oscillations were observed thereafter. ITEM NO. C.8: Total power failure at 220/132 kV Hatia S/s (JUSNL) on 14/09/15 at 11:38hrs. In 36th PCC, PCC advised JUSNL to check the following and report to ERPC/ERLDC:

1. The main and backup protection of 132kV Hatia-Kanke line at 132kV Kanke end needs to be tested and JUSNL should find out why the fault was not detected from Kanke end.

2. CB of 132kV Hatia-Kanke line at 132kV Hatia end should be tested. 3. Protection system of 220/132kV, 150 MVA T/F-I at 220 kV Hatia is to be tested. 4. The directional feature of over current protection of 132kV Chandil-Hatia S/C at both end to

be verified. 5. JUSNL was advised to collect the tripping details of ICTs and generators at PTPS.

In 37th PCC, JUSNL informed that relay settings have reviewed and for further review and co-ordination of relay at Hatia complex a work order have already been placed with M/s Alstom on 10/08/2015. It will be carried out soon. JUSNL may update.


Deliberation in the meeting JUSNL informed that M/s Alstom yet to review the relay settings. PCC advised JUSNL to pursue with Alstom. ITEM NO. C.9: Repeated trippings in BSPTCL (Madhepura) system at on 07.09.15 and

08.09.15. In 36th PCC, Powergrid was advised to check the zone settings of 220kV Purnea(PG)- Madhepura line-1 at Purnea(PG) end. In the meeting, BSPTCL reported that LBB protection at Madhepura was mal-operated and tripped both 220/132kV ICTs. In 35th PCC, BSPTCL was advised to expedite the Installation of PLCC system for 220 KV Purnea(PG)-Madhepura line-I and II in order to enable the inter-tripping and auto reclose features.

• To carry out protection co-ordination of 220 kV Madhepura, 132 kV Kishenggunj, Forbesgunj and adjoining areas.

BSPTCL may update the status of LBB system at 220kV Madhepura S/s. In 37th PCC, BSPTCL informed that the work has been initiated and the details will be submitted soon. BSPTCL may update. Deliberation in the meeting BSPTCL informed that work is in progress. ITEM NO. C.10: Total Power failure in 220kV Biharshariff (BSPTCL) System at 11:01 hrs on

10.09.15. In 36th PCC Meeting, Powergrid explained that there was a fault in 220kV Biharshariff-Bodhgaya line, which caused the tripping of 400/220 kV ICTs at Biharshariff end. Powergrid informed that a letter has been written to BSPTCL on this issue. PCC advised BSPTCL to check the relays of 220kV Biharshariff-Bodhgaya line at 220kV Biharshariff end. In 37th PCC, BSPTCL informed that the work has been initiated and the details will be submitted soon. BSPTCL may update. Deliberation in the meeting BSPTCL informed that the work has been initiated and the details will be submitted soon. ITEM NO. C.11: Disturbance at 220kV Dehri (BSPTCL) and 220kV Sasaram (PG) on 15/08/15 at

13:20hrs. In 35th PCC, BSPTCL was advised to carry out the following:

• Check the CB of 132kV Dehri-Banjari line at 132 kV Dehri end. • The protection relay settings of ICTs at Dehri S/s to be coordinated with line relays.


In 37th PCC, BSPTCL informed that the work has been initiated and the details will be submitted soon. BSPTCL may update. Deliberation in the meeting BSPTCL informed that they have tested the CBs and found CBs are healthy. The relay settings of ICTs at Dehri S/s have been coordinated with line relays. ITEM NO. C.12: Total power failure at 220kV Tarkera S/s in OPTCL system on 06/07/15 at

09:55 & 10:54 hrs. In 37th PCC, OPTCL informed that 1. Shutdown has been sought for testing of 220kV Budhipadr -Tarkera feeders. The relays will be tested as soon as shut down is permitted.---In progress 2. Replacement of ABB make RAZFE Relay for 220kV Rourkela 1 & 2 feeder as well as distance protection relay for 220kV Budhipadar Ckt-1 at 220kV Tarkera will be replaced as soon as shutdown is available. 3 Nos SIEMENS DP relay 7SA 52 are available at site.---Completed 3. On numerical measurement display, direction checked to be normal. ---Completed 4. Testing of relays are in progress at Tarkera Grid Substation .---Completed 5. After installation of DP relays in 220kV system. Old DP relays in 132kV system will be replaced.---In progress 6. DP setting as decided in Special PCC meeting on 20.07.2015 is also being adopted in intra-state lines with minor modification in Z3 setting in case to case.---In progress OPTCL may update. Deliberation in the meeting OPTCL updated the status as follows: 1. Shutdown has been sought for testing of 220kV Budhipadr -Tarkera feeders. The relays will be tested as soon as shut down is permitted.---Completed 2. Replacement of ABB make RAZFE Relay for 220kV Rourkela 1 & 2 feeder as well as distance protection relay for 220kV Budhipadar Ckt-1 at 220kV Tarkera will be replaced as soon as shutdown is available. 3 Nos SIEMENS DP relay 7SA 52 are available at site.---Completed 3. On numerical measurement display, direction checked to be normal. ---Completed 4. Testing of relays are in progress at Tarkera Grid Substation .---Completed 5. After installation of DP relays in 220kV system. Old DP relays in 132kV system will be replaced.---In progress 6. DP setting as decided in Special PCC meeting on 20.07.2015 is also being adopted in intra-state lines with minor modification in Z3 setting in case to case.---Completed ITEM NO. C.13: Disturbance at 400kV Sagardighi S/s (WBPDCL) on 08/05/15 at 11:00hrs.

In 33rd PCC, it was informed that the over current settings of Powergrid feeders from Sagardighi was kept at 200 % with instantaneous trip settings which was provided by Powergrid. WBPDCL requested Powergrid to review the existing settings and advice if there is a need to change. Minutes of 38th PCC meeting 26

PCC felt that the O/C settings need to be reviewed and advised Powergrid to check the settings and provide the reviewed settings to WBPDCL for implementation of the same. Powergrid agreed. In 34th PCC, WBPDCL informed that they have sent the relay settings to Powergrid. PCC advised Powergrid to review the settings and send to WBPDCL. In 36th PCC, WBPDCL informed that they received the revised settings from Powergrid. In 37th PCC, WBPDCL informed that the revised settings will be incorporated on opportunity shutdown. WBPDCL may update. Deliberation in the meeting WBPDCL informed that in the revised settings the high set setting for over current relay has been withdrawn. PCC felt that high set setting for over current relay has been withdrawn to have proper coordination with the other end relays and advised WBPDCL to implement the revised settings received from Powergrid. ITEM NO. C.14: Members may update the following: 1. Powergrid informed that Bus-bar protection at 220kV Birpara S/s will be installed within 2-3

months. In 37th PCC, Powergrid informed that Bus-bar protection at 220kV Birpara S/s will be installed after November, 2015. Powergrid may update. Deliberation in the meeting Powergrid informed that Bus-bar protection at 220kV Birpara S/s will be installed by 1st week of January 2016. 2. OPTCL may please update the latest status on following substations:

In 37th PCC, OPTCL informed that

The issue of LBB maloperation at 220kV Meeramundali S/s at 04:59hrs on 18/09/15 has been taken up with Siemens and rectification in LBB logic is in progress.

OPTCL informed that they will review the logic of all the newly installed LBB protection.

OPTCL may update. Deliberation in the meeting OPTCL informed that Siemens assured to send their engineer to rectify the problem.

ITEM NO. C.15: PROTECTION PHILOSOPHY OF EASTERN REGION The Protection Philosophy finalized in special PCC meeting held on 20th July, 2015 is as given below: Minutes of 38th PCC meeting 27

Sl. No.

Zone Direction Protected Line Reach Settings

Time Settings (in Seconds)

Remarks

1 Zone-1 Forward 80% Instantaneous (0) As per CEA

2a Zone-2 Forward For single ckt- 120 % of the protected line

0.5 to 0.6 - if Z2 reach overreaches the 50% of the shortest line ; 0.35- otherwise

As per CEA

For double ckt- 150 % of the protected line

As per CEA

2b Zone-2 (for 220 kV and below

voltage Transmission

lines of utilities)

Forward 120 % of the protected line, or 100% of the protected line + 50% of the adjacent shortest line

0.35 As per CEA with minor

changes

3 Zone-3 Forward 120 % of the (Protected line + Next longest line)

0.8 - 1.0 As per CEA

4 Zone-4 Reverse 10%- for long lines (for line length of 100 km and above) 20%- for shot lines (for line length of less than 100 km)

0.5

As per CEA

Note: 1) Zone-2:- Z2 Reach should not encroach the next lower voltage level. 2) Zone-3:- If Z3 reach encroaches in next voltage level (after considering “in-feed”), then Z3 time

must be coordinated with the fault clearing time of remote end transformer. 3) Zone-4:- If utility uses carrier blocking scheme, then the Z4 reach may be increased as per the

requirement. It should cover the LBB of local bus bar and should be coordinated with Z2 time of the all other lines.

4) The above settings are recommended primarily (exclusively) for uncompensated lines. All the constituents agreed on the principles read with notes as above. In 37th PCC, it was informed that the issue was also discussed in 31st TCC/ERPC meeting wherein the line parameters was agreed as given below:

Tower R1 X1 B1 R0 X0 B0 Xm Xom Load-ability

132kV D/C Single Panther 0.1400 0.4010 2.8600 0.3540 1.3300 1.7800 0.2630 0.8220 220kV D/C Single Zebra 0.0697 0.3980 2.9100 0.2810 1.2900 1.8400 0.2510 0.8030 400.00 400kV S/C Twin Moose 0.0288 0.3280 3.5500 0.2850 1.0200 2.6100 400kV D/C Twin Moose 0.0288 0.3070 3.7700 0.2690 1.0700 2.2900 0.2080 0.6750 1500.00 400kV D/C Quad Moose 0.0147 0.2530 4.5800 0.2480 1.0000 2.6400 0.2030 0.6620 2000.00 400kV D/C Tripple snowbird 0.0195 0.2700 4.2700 0.2000 0.8620 2.4900 0.2130 0.5040 400kV D/C Twin Lapwing 0.0197 0.3060 3.8000 0.2050 0.9010 2.3700 0.1700 0.5020 765kV S/c Quad Bersimis 0.0114 0.2860 4.0200 0.2400 0.9360 2.6000 3500.00

765kV D/C Hexa zebra 0.0446 0.9070 1.2700 0.8310 3.4100 0.7190 220 kV SINGLE ZEBRA S/C 0.074875 0.39925 0.219978 1.339228 132 kV SINGLE PANTHER S/C 0.1622 0.3861 0.4056 1.622


TCC advised all the other constituents to implement the revised zone settings and submit the settings to ERPC. Members may update. Deliberation in the meeting WBSETCL, DVC and OPTCL were submitted the zone settings. PCC advised all other constituents to implement the revised zone settings and submit the settings to ERPC/ERLDC at the earliest. ITEM NO. C.16: Third Party Protection Audit 1. Status of 1st Third Party Protection Audit:

The compliance status of 1st Third Party Protection Audit observations is as follows:

Name of Constituents Total Observations Complied % of

Compliance Powergrid 54 37 68.52 NTPC 16 14 87.50 NHPC 1 1 100.00 DVC 40 26 65.00 WB 68 27 39.71 Odisha 59 38 64.41 JUSNL 34 16 47.06 BSPTCL 16 5 31.25 IPP (GMR, Sterlite and MPL) 5 5 100.00

The substation wise status of compliance are available at ERPC website (Observations include PLCC rectification/activation which needs a comprehensive plan).

Members may update. Deliberation in the meeting PCC advised all the constituents to comply the pending observations at the earliest. 2. Schedule for 2nd Third Party Protection Audit:

The latest status of 2nd Third Party Protection audit is as follows:

1) Jeerat (PG) Completed on 15th July 2015 2) Subashgram (PG) Completed on 16th July 2015 3) Kolaghat TPS (WBPDCL)- Completed on 7th August 2015 4) Kharagpur (WBSETCL) 400/220kV - Completed on 7th August 2015 5) Bidhannagar (WBSETCL) 400 &220kV Completed on 8th September, 2015 6) Durgapur (PG) 400kV S/s Completed on 10th September, 2015 7) DSTPS(DVC) 400/220kV Completed on 9th September, 2015 8) Mejia (DVC) TPS 400/220kV Completed on 11th September, 2015 9) 400/220/132kV Mendhasal (OPTCL) Completed on 2nd November, 2015 10) 400/220kV Talcher STPS (NTPC) Completed on 3rd November, 2015 11) 765/400kV Angul (PG) Completed on 4th November, 2015 12) 400kV JITPL Completed on 5th November, 2015 13) 400kV GMR Completed on 5th November, 2015


In 115th OCC, Members decided to carry out the audit for 400kV Bakreswar (WBPDCL), Sagardighi (WBPDCL), Farakka (NTPC), Malda (PG) & Behrampur(PG) in December, 15/January, 16. Members may note. Deliberation in the meeting Members noted. ITEM NO. C.17: Any other items. 1. Bus segregation of 400kV Maithon (PG) and Durgapur (PG) S/s Powegrid shared the SLDs of bus segregation at 400kV Maithon (PG) and Durgapur (PG) S/s and informed that segregation of bus 1 and 3 are completed at Maithon and 2 and 4 would be completed by 2nd week of January, 2016. SLDs are enclosed at Annexure-C17.1.

Deliberation in the meeting PCC advised Powergrid to revise the protection settings as per the new bus bar scheme. ERLDC shared the load pattern at 400kV Maithon (PG) and Durgapur (PG) S/s. Details are enclosed at Annexure-C17.2.

Meeting ended with vote of thanks to the chair.

******************


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FORMAT FOR REPORTING SYSTEM DISTURBANCES ( Detailed Report )

OCCURRENCE REPORT

(1) Date & Time of Occurrence

(2) Name of the Sub Station / Generating Station

(3) Details of Occurrence

(4) At the time of occurrence the disposition of the feeders was as below

For one and half breaker scheme

Feeder I Feeder II Tie-breaker (On/Off Diameter 1

Diameter 2

Diameter 3

Bus A Bus B

BUS COUPLER BREAKER WAS “ON” /”OFF”-

Annexure-B1

(5) Sequence of Trippings

(6) Relay Indication for Faulted Line/Transformer/Bus

(A) Relay Indication

Sl. No.

Name of Bay / Line

Local End Relay type / Make And Indications

Remote End Relay type / Make And Indications

1.

(7) Location and nature of Fault

(8) PLCC counter readings

Local end Remote end

Before After Before After CH I IN-1

OUT-1 IN-2

OUT-2 CH II IN-1

OUT-1 IN-2

OUT-2

(9) Analysis:-

(10) Restoration

Sl.No. desciption From To Duration 1.

(11) Remedial Measures / Lesson Learnt

Enclosure ::-

1) Schematic Diagram showing position of (ON/OFF) breakers, Isolators and Relay Indications.

Annexure-B7

S.NO LINE NAME TRIP DATE TRIP TIME RESTORATION DATE

RESTORATION TIME

Fault Clearance

time in msec

Relay Indication LOCAL END

Relay Indication REMOTE END

Auto Recloser statusDR/EL

received within 24

Hrs

DR/EL received after 24

Hrs

Deliberation in the meeting

1 220 KV BIRPARA-SALAKTI D/C 20.11.15 16:49 20.11.15I- 17:40 II-17:59

approx 900 ms

R-N, Z-II (both Ckt)F/C 807 A - ckt I & 799 A - ckt II

F/L 159 km from BirparaCVT Fuse failure A/R lock out

Not operated A/R locked out No Yes R-N FAULT, Bus fault at Salakati end.

2 220KV GAYA-BODHGAYA-I 30.11.15 02:10 30.11.15 02:47 approx 360 ms

No information received No information received Not observed in PMU data

No No B-N FAULT, PLCC is not in service

1 400KV ANGUL-TALCHER 02.11.15 17:05 02.11.15 17:40 --Master trip Relay Mal-

operationDT Received -- Yes No

DT RECEIVED AT TALCHER END (No fault observed in PMU data), No fault in the system, DT send during

charging the bus bar bay unit.

2 400KV ANGUL-MERAMUNDALI-II 02.11.15 17:08 02.11.15 17:25 -- No information received No information received -- No NoTRIPPED FROM MERAMUNDALI END ONLY (no fault

observed in PMU data)

3 400 KV TALCHER- MEERAMUNDALI 26.11.15 10:08 26.11.15 11:33 -- DT Received at Talcher No information received -- No No DT RECEIVED AT TALCHER

4 400 KV FARAKKA-MALDA-II 29.11.15 12:04 29.11.15 15:27 -- --Switched off due to

attend CT problem at Malda end

-- -- --

STEP CHANGE IN R & Y PHASE VOLTAGES IS OBSERVED IN PMU DATA, Hand tripped hot spot observedat CT

due to problem in breaker. Breaker has been replaced.

5765 KV NEW RANCHI -

DHARAMJAYGARH30.11.15 16:35 30.11.15 18:02 -- DT Received at New Ranchi No information received -- No No DT RECEIVED AT NEW RANCHI

220kV & above Intra Region Transmission Lines

No autorecloser operation observed in PMU data

Fault Not observed in PMU data

132kV Purnea Madhepura Biharshariff Begusarai Forbesgunj Chandil Ramchandrapur Adityapur1 SLD of all the affected and surround Sub-station (with CT location) √ √ √ Yet to Submit √ √ √ √2 Year of manufacturing of all equipments Yet to Submit √ √ √ √ √ √ √

3Comprehensive CT details along with name plate (with connected./adopted ratio ) √ √ √ √ √ √ √ √

4 VT details √ √ √ √ √ √ √ √

5Fault level- 3-phase as well as 1-phase (line length, conductor details and Transformer details for computing fault level) √ Recieved from ERLDC

6 Transformer details (Rating, impedance) √ √ √Impedance is not mentioned √ √ √ √

7 Availabitity of Auto-Reclosure feature Not active Not active Not active Not active Not active Not active Not active Not active8 Availability of carier protection Not active Not active Not active Not active Not active Not active Not active Not active9 Availability of Bus- differential and LBB Protection Not available LBB Not active Not available Not available LBB Bus bar and LBB LBB

10 Junction Box (JB) details ok ok ok ok ok ok ok ok

11Cable details used for CT connections (Cross section/core of cable, Junction Box (JB) details & length of cable between JB & control panel) Yet to Submit Yet to Submit √ Yet to Submit Yet to Submit √ √ √

12 Grid earthing resistance (With latest test report) Yet to Submit Yet to Submit √ Yet to Submit Yet to Submit √Resistance is ≥ 1 ohm √

13 Breaker details (operating time) √

Operating time is not mentioned √

Operating time is not mentioned

Operating time is not mentioned √ Yet to Submit √

14 CT/PT earthing details Yet to Submit Yet to Submit Yet to Submit Yet to Submit Yet to Submit Yet to Submit Yet to Submit Yet to Submit

15Relay details (Relay type, model, settings, manufacturing, basis of settings) * √ Yet to Submit Yet to Submit Yet to Submit √ √ √ √

16 Scheme adopted for protection settings for lines and transformers17 DC system details with charger and battery** Yet to Submit Yet to Submit √ Yet to Submit √ √ √ √18 Details of transmission line protection as per the format Yet to Submit Yet to Submit √ Yet to Submit Yet to Submit √ √ √19 Details of transformer protection as per the format Yet to Submit Yet to Submit √ Yet to Submit Yet to Submit √ √ √

** positve/negative earth details* Last relay testing report (reach test/function test)is to be submitted

Annexure-C1

Distance relay settings are implemented as per the ERPC recommended zone settings

Status of data recieved from BSPTCL and JUSNL

BSPTCL JUSNLDetails required

Recieved from ERLDC

Annexure-C17.1

Annexure-C17.2

LOAD PATTERN AT MAITHON SUBSTATION

BUS-1&2:

1) ICT-1: +245MW 2) ICT-2: +245MW 3) Gaya-1: -495MW 4) Gaya-2: -495MW 5) KHG-2: +240MW 6) Mejia-2: -275MW 7) Mejia-1: -200MW 8) Jamshedpur: -45MW

BUS-3&4:

1) KHG-1: +150MW 2) RB-1: -510MW 3) RB-2: -510MW 4) Mejia-3: -200MW 5) RTPS: -296MW 6) Ranchi: -85MW 7) DGP-1: +210MW 8) DGP-2: +210MW

LOAD PATTERN AT DURGAPUR:

BUS-1&2:

1) Farakka-1: - 35MW 2) S’Dighi-1: +120MW 3) S’Dighi-2: +120MW 4) B’Nagar-1: +70MW 5) B’Nagar-2: +70MW 6) Jamshedpur: +135MW 7) ICT-1: +80MW

BUS-3&4:

1) Farakka-2: -35MW 2) Maithon-1: -235MW 3) Maithon-2: -235MW 4) ICT-2: +80MW 5) Jamshedpur-1: Terminated at DVC Andal 6) Jamshedpur-2: Terminated at DVC Andal

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