97th OCC 21st PCC Minutes Final 16.05.2014

North Eastern Regional Power Committee

MINUTES OF THE 97thOPERATION COORDINATION& 21st PROTECTION COORDINATION SUB-COMMITTEE

MEETINGS OF NERPC

Date : 06/05/2014 (Tuesday)Time : 10:30 hrsVenue : “Hotel Nandan”, Guwahati.

The List of Participants in the 97thOCC & 21st PCC Meeting is attached at Annexure – I

Shri S.K. Ray Mohapatra, Member Secretary (I/C), NERPC welcomed all the delegates of constituents including Shri A. Perme, Chief Engineer (TP&MZ), Dept. of Power, Ar. Pradesh, Shri J. K. Sharma, CGM, SLDC and Shri M. Banerjee, GM (Plant), OTPC to the 97th OCC & 21st PCC meetings. He informed that the demand met during the month of April, 2014 has touched 2200 MW and the import from ER touched all time high 800 MW. The above demand was met especially during Lok Sabha election. The generation in the range of 300MW to 330MW from OTPC’s plant at Palatana has provided great relief to the constituents of the region during this lean hydro period. Further, he informed that since March 2014, OTPC has been requesting for shutdown of the plant to carry our Performance Guarantee (PG) tests of Unit #1; but due to acute shortage of power and Parliament election process, the forum had requested OTPC to defer the shut down program till 2nd week of May. During last OCC meeting OTPC had highlighted about the urgency of shutdown of Unti#1. Moreover, as per contractual agreement, BHEL is to carry out PG test before handing over the Generating Unit to OTPC and hence the forum may take decision on approval of shut down of Unit #1. He highlighted about the status of funding from NLCPR-Central for “Rectification of various deficiencies including renovation and modernization of protection system in existing substations and Generating stations of 132kV and above voltage class”. He also stated that first meeting of Operation and Protection sub-group was held at NERLDC, Shillong on

Minutes of 97thOCC & 21st PCC meetings held on 06th May, 2014 at Guwahati

11.04.2014 as suggested by the OCC forum. He mentioned that OTPC has requested NERPC to include representative from their organization as member of the sub-group. He once again requested the constituent states of NER to furnish the required information regarding Power supply to Rural areas in their state in the simplified format, circulated earlier to all, by 15th of every month for the previous month as the same is to be submitted to CEA / MoP on monthly basis. He also informed that workshop on Smart Grid organized by Smart Grid Forum (SGF) of India under aegis of Assam will be held on 07.05.2014 at Hotel Brahmaputra Ashok, Guwahati and requested all delegates of the region to avail the opportunity. He requested all the constituents to actively participate in the meeting for fruitful outcome.

Thereafter, Member Secretary I/C requested Shri B. Lyngkhoi, SE(O), NERPC to take up the agenda items for discussion.

A. C O N F I R M A T I O N O F M I N U T E S

CONFIRMATION OF MINUTES OF 96 th MEETING OF OPERATION SUB- COMMITTEE OF NERPC.

SE (O) informed that the minutes of 96th meeting of Operation Sub-committee held on 4th April, 2014 at NERLDC, Shillong were circulated vide letter No. NERPC/SE (O)/OCC/2014/0143-0176 dated 30th April, 2014.

CONFIRMATION OF MINUTES OF 20 th MEETING OF PROTECTION SUB- COMMITTEE OF NERPC.

Similarly, the minutes of 20th meeting of Protection Sub-committee held on 4th April, 2014 at NERLDC, Shillong were circulated vide letter No. NERPC/SE (O)/OCC/2014/0143-0176 dated 30th April, 2014.

The Sub-committee confirmed the minutes of 96th OCCM & 20th PCCM of NERPC as no observations or comments was received from the constituents.

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SE(O), NERPC then requested NERLDC to give the presentation on the grid performance of NER during the month of April, 2014.

The presentation as given by NERLDC is given as below:

I T E M S F O R D I S C U S S I O N

B.1. OPERATIONAL PERFORMANCE AND GRID DISCIPLINE DURING APRIL, 2014

As per the data made available by NERLDC, the grid performance parameters for April, 2014 are given below:

NER PERFORMANCE DURING APRIL, 2014

Energy Met (MU) Energy Reqr. (MU)

States Apr-14 Mar-14%

inc(+)/dec(-)

Apr-14 Mar-14%

inc(+)/dec(-)

Ar. Pradesh 44.36 46.00 -3.6 47.08 49.04 -4.0Assam 585.78 560.35 4.5 630.17 601.50 4.8

Manipur 45.89 46.86 -2.1 49.19 50.19 -2.0Meghalaya 113.19 129.69 -12.7 132.48 150.92 -12.2Mizoram 31.06 32.76 -5.2 32.64 34.59 -5.6Nagaland 45.69 46.05 -0.8 48.25 48.33 -0.2Tripura 82.07 89.75 -8.6 85.14 91.54 -7.0Region 948.0 951.5 -0.4 1024.95 1026.11 -0.1

Demand Met (MW) Demand in (MW)

States Apr-14 Mar-14%

inc(+)/dec(-)

Apr-14 Mar-14%

inc(+)/dec(-)

Ar. Pradesh 104 122 -14.8 105 123 -14.6Assam 1230 1164 5.7 1343 1218 10.3

Manipur 112 133 -15.8 115 134 -14.2Meghalaya 272 278 -2.2 280 286 -2.1Mizoram 76 81 -6.2 77 83 -7.2Nagaland 102 99 3.0 105 100 5.0Tripura 247 245 0.8 247 245 0.8Region 2045 1995 2.5 2197 2110 4.1

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REGIONAL GENERATION & INTER-REGIONAL EXCHANGE IN MU AVERAGE FREQUENCY (Hz)

Month----> Apr-14 Mar-14 Month----> Apr-14 Mar-14Total Generation in NER (Gross) 697.83 720.861 % of Time % of TimeTotal Central

Sector Generation

(Gross)468.63 481.438 Below 49.7

Hz 30.09 14.32

Total State Sector

Generation (Gross)

229.2 239.423Between

49.7 to 50.2 Hz

52.7 51.4

Inter-Regional Energy

ExchangeAbove 50.2

Hz 17.21 34.28

(a) NER-ER 15.99 19.964 Average 49.95 50.01(b) ER-NER 287.39 268.464 Maximum 50.56 50.73

© Net Import 271.4 248.5 Minimum 49.49 49.08

From the above table, it is seen that energy requirement met of the region has decreased where as Demand met in mw increased considerably.

The Summary of Messages issued by NERLDC for the constituents of NER for the Month of April 2014 is given as below:

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Constituents Deviation Violation Message Zero crossing Violation Message

Alert Emergency Total Alert Emergency TotalAP 6 100 106 4 30 34Assam 1 60 61 2 19 21Manipur 3 85 88 2 10 12Meghalaya 4 59 63 3 10 13Mizoram 3 84 87 3 11 14Nagaland 3 77 80 1 15 16Tripura 3 99 102 4 16 20AGBPP 0 2 2 0 0 0AGTPP 0 0 0 0 0 0RHEP 0 1 1 0 0 0KOPILI 0 0 0 0 0 0KHANDONG 0 0 0 0 0 0KOPILI –II 0 0 0 0 0 0DHEP 0 0 0 0 0 0LOKTAK 2 11 13 0 0 0PALATANA 0 6 6 0 0 0


FOLLOW UP ACTION

C.1 Synchronization of Pallatana Module -II

The CoD of Unit # 1 of OTPC was declared on 04.01.2014 and 3rd Gas Booster Compressor (GBC) is still in BHEL’s factory at Hyderabad.

During 97th OCC meeting, GM, OTPC informed the house that shut down of Unit # 1 is required for seven (7) days [5 days for preparation of PG test and 2 days for PG test including IDLN tuning] for carrying out Combined Cycle Performance Guarantee (PG) test including IDLN tuning. As per contractual agreement, BHEL is supposed to carry out PG test of the Unit within one month of declaration of CoD in order to establish the capability of GT and ST to generate upto their rated capacity. PG test will increase the Megawatt loading of Gas Turbine (GT) by about 15MW to 20MW as GT compressor will undergo detergent washing. Moreover, General Electric, the manufacturer of GT, wants to carry out borescopic inspection as problem in particular zone of GT is suspected because of which the machine had tripped on combustion failure on various occasions. This situation may lead to break down of machine if the condition persists for longer time. In such case, outage duration of Unit would be quite long and the stake holders of plant are likely face huge commercial loss. He then requested the forum to allow shutdown of Unit #1 w.e.f. 18.05.2014 for a period of 7 (seven) days. Further, he informed that complete shutdown of Unit # 1 is actually from 18.05.2014 to 21.05.2014. The generation is expected to increase gradually from 22.05.2014 and from 23.05.2014 onwards the generating Unit will operate at base load / full load. He wanted the healthiness / availability of Palatana-Silchar 400kV line during last two days of the PG test when Unit will run at full load. He also highlighted about the tripping of gas booster compressor motor due to low voltage problem.

After detailed discussion, the forum agreed to the proposal of OTPC for shut down of Unit # 1 for 7 (seven) days w.e.f. 18.05.204 to 24.05.2014 with the following conditions:

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1. No reduction / curtailment in ATC/TTC in NER-ER corridor should take place during the period of shutdown

2. NERPC/NERLDC will have a close co-ordination with Eastern Region counterparts i.e. ERPC/ERLDC so that ATC/TTC is maintained at maximum level.

3. OTPC should furnish their schedule 2 (two) days in advance to NERLDC before availing shutdown along with schedule of generation / injection to grid from 22-05-2014.

4. OTPC should not deviate from/defer the period approved by the forum.

5. NERLDC may explore the possibility of enhancement of generations from the hydro stations / gas based station in the region to meet the shortfall during the shutdown / outage period of generating Unit # 1 of OTPC.

The subcommittee also requested OTPC to take up with ONGC for increase in quantum of gas supply so that Unit # 2 can be taken up for declaration of CoD. The GM, OTPC informed that negotiation and discussion is going on with ONGC for enhancement in quantum gas supply and positive outcome is expected very soon.

The Sub-committee also reviewed the status of commissioning of second unit of OTPC at Pallatana, following Transmission lines of POWERGRID and substation at Azara of Assam. The status as informed by OTPC, Assam and POWERGRID is as follows:

SN Items Present status1 Trial operation and CoD of Unit -II of OTPC

at PalatanaTrail operation is expected

in June 2014 and CoD is expected in Sept, 2014

2 400KV D/C Silchar - Melriat line December, 2014

3 400KV D/C Silchar - Imphal line June, 2014

4 220KV D/C Mariani (New) – Mokokchung June, 2014

5 400KV D/C Byrnihat-Bongaigaon line

Byrnihat-Azara section of line is almost complete except stringing of 2 spans, which is expected to be completed by May 2014 subject to clearance by Appellate Tribunal for

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Electricity (APTEL) and Azara–Bongaigaon section of line is expected by June 2014

6 400kV Balipara – Bongaigaon D/C line # 3 & 4 with FSC

May, 2014 subject to availability of forest clearance for 5.2 kms of the line.[FSC commissioned on 11.01.2014]

7 400/220 kV sub-station at Azara of Assam

Sub-station is ready and test charging has been carried out on 28.03.2014. The LILO arrangement is also complete. If the 400kV Byrnihat – Ajara line is commissioned by POWERGRID, then the substation at Azara can be charged at 400kV level.

The Sub-committee requested OTPC to furnish the details for trial run of Unit #2 in advance to NERLDC. OTPC agreed.

The Sub-committee noted as above.

C.2 SPS scheme for Pallatana

The following four (4) System Protection Scheme (SPS) associated with generating Unit#1 (363.3MW) of OTPC at Palatana has been planned for NER:

Case 1: Tripping of generating unit of OTPC at Palatana

Case 2: Tripping of 400 kV D/C Palatana- Silchar line (with generation from OTPC’s plant at Palatana)

Case 3: Tripping of 400 kV Silchar-Byrnihat line (with generation from OTPC’s plant at Palatana)

Case 4: Tripping of 400 KV Silchar – Byrnihat line (without generation from OTPC’s plant at Palatana)

During 95th OCC meeting, the Sub-committee had reviewed the status of implementation of the scheme and the status was as follows:

Case I & Case IV: Has already been implemented

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Case 2-3: GM, OTPC stated that implementation of SPS -2 & 3 mentioned above was discussed in detail and the scheme was finalized in the meeting held with BHEL at Palatana on 17.01.2014. Subsequently some modification has been carried out by BHEL and same will be circulated to all. The commercial offer for implementation of scheme is expected in 10days time and the scheme is will be implemented very soon after completion of procurement process.

OTPC had requested POWERGRID to look into following issues:

(a) SPS at OTPC end should not be modified with commissioning of 2nd Circuit of Silchar _ Bongaigaon 400kV line.

(b)Trip command from two different sources should be available to desynchronize the machine to avoid unwarranted tripping of generating Unit when the generation is more than 200MW. During 93rd OCC meeting, subcommittee had suggested OTPC for getting input from Circuit breakers at both ends of the line (Silchar & Byrnihat) through communication link and to discuss the matter with POWERGRID.

(c) Two out of three logics [i.e inputs from circuit breaker (s), master trip relay (s) etc.] shall be utilized for desynchronisation of Gas Turbines. During 93rd

OCC meeting, subcommittee had suggested OTPC to discuss the matter with POWERGRID.

During the 96th OCC meeting, DGM, NERTS had also informed that SPS-5 (in connection with tripping of 220 KV Byrnihat – Misa D/C with generation at OTPC) wiring diagram has already been furnished to NERPC/NERLDC. He had mentioned that since the scheme has to be implemented at 220 KV sub-station of Me.ECL at Byrnihat, their consent is necessary before implementation of the scheme.

The forum had requested NERPC to take up the matter with Director (Trans) of Me.ECL regarding implementation of the scheme.

Deliberation of the Committee

The Sub-committee expressed concern for delay in implementation of SPS -2 & 3 and once again requested OTPC to pursue with BHEL for early implementation of the scheme.

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GM, OTPC informed that commercial offer for Rs. 13.5 Crores has been received from BHEL for implementation of the scheme and OTPC feels that the cost is exorbitantly high and the matter is under review and discussion is going on with BHEL about the cost.

The forum requested OTPC to share the detail with the subcommittee and forum will try to help. OTPC agreed. The forum insisted for early implementation of SPS-2 & 3, otherwise the safety and security of the grid is / will be in danger.

DGM, NERTS enquired about the requirement of SPS-5 after commissioning of Byrnihat – Azara 400kV line.

The sub-committee requested NERLDC to carry out the system studies so that the requirement of SPS-5 can be reviewed.


C.3 Details of Installations and self-certification (by STUs and CTUs) in respect of operationalisation of Under Frequency Relays (UFRs) in NER systems and additional requirement of UFR and df/dt relays:

During 97th OCC meeting, the Committee reviewed the status of UFR based load shedding as given below:

Ar. Pradesh: CE, Ar. Pradesh stated that installation of UFRs for Stage-I i.e for load shedding of 5MW (at 92.2Hz) has been completed. The identification of feeders for installation of UFRs for load relief of another 15 MW (5 MW in each of 3 remaining stages) has been completed i.e. one at 33 kV Bhalukpong and two at Lekhi S/S. Installation of remaining stages would be completed by June, 2014.

Assam: UFRs based load shedding for 220MW have been implemented.

Manipur: During 96th OCC, Manipur stated that identification of the feeders and installation of UFRs for the required quantum of UFR based load shedding at different stages will be completed by April 2014. Since no representative was present, the status could not be updated.

Meghalaya: EE, SLDC informed that the existing standalone UFRs for Stage – I & II has already been installed at 33 kV Mawphlang S/S. Further, EE, SLDC

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informed that the installation of UFRs for Stage – III & IV will be completed by May 2014.

Mizoram: During 96th OCC, representative from Mizoram stated that the work associated with utilization of the existing standalone UFRs for Stage – I & II of revised UFR based load shedding would be completed by April, 2014. The remaining work will be completed by June 2014. Since no representative was present, the status could not be updated.

Nagaland: During 94th OCC meeting, EE, SLDC had stated that UFR for stage – III is already in place and installation of UFRs for Stage – I & II will be completed by February, 2014 and installation of UFRs for Stage – IV will be completed by April, 2014. Since no representative was present, the status could not be updated.

Tripura: The representative of Tripura informed that the work associated with utilization of the existing standalone UFRs for Stage – I & II of revised UFR based load shedding has been completed and the installation of UFRs for Stage – III &IV would be completed by July 2014.

The subcommittee once again requested all constituent states of the region to complete the installation of UFRs required for all four stages at the earliest.

The subcommittee requested all constituent states of the region to provide details of UFR operation [i.e. location, frequency at which UFRs operated / frequency setting of UFRs and the quantum of load shedding happened due to operation of UFRs] on 19-03-2014, on the day of a major grid disturbance in NER, in the next OCC meeting.


C.4 Lines under long outages

During the 97th OCC meeting, the issue for restoration of these lines was reviewed by the committee and the status was as follows:

a) 220kV BTPS – Agia line (one ckt) – [Since Nov’97]: The representative of Assam informed that the work associated with 20 kms of the line (out of 42km) has

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been completed and the target for completion of rest of the work is June, 2014.

b) 132kV Mariani – Mokokchung line - [Since Apr’02]

During 93rd OCC meeting, SDO, DoP, Nagaland had informed that the work associated with replacement of insulators in the section of line within Nagaland territory has been completed and the line was test charged in January, 2014 from Mokokchung till Langtho (the border point of Nagaland) and now the remaining portion from Langtho – Mariani, which is under the jurisdiction of Assam, has to be completed by Assam. AGM of Assam had requested Nagaland to check the adequacy of CT ratio at Mokokchong end and had enquired about the test charging voltage level. DGM, POWERGRID had requested Nagaland to check their CT ratio before charging the above line.

During 95th OCC meeting, the representative of Nagaland informed that CE, Nagaland has already communicated to MD, AGECL in this regard vide their letter No. CEL/TB/NERPC/OCC/MEETING/3326 dated 04-03-2014. The representative of Assam informed that work associated with the section of the line in Assam territory, beyond Langtho, was executed by Nagaland on deposit work basis and hence replacement of insulator in other section of line, within territory of Assam, can be taken up by Nagaland on deposit work basis. During 97th OCC meeting, the representative of Assam informed that the inspection of line will be completed by June 15, 2014 to assess the quantity of insulators required for replacement and the condition of towers and accordingly Assam will co-ordinate with Nagaland to sort out the matter. Since no representative from Nagaland was present, the subcommittee requested Assam to sort out the issue with Nagaland as early as possible.

c) 39km of 132kV Rengpang – Jiribam line – [Since Oct’02]

During 93th OCC, EE, DoP, Manipur had informed that site for relocation of new tower (due to ground clearance problem causeddue to road cutting by BRTF) has been identified. During 96th OCC meeting, the representative of Manipur had informed that the work is in progress and line would be charged by April, 2014. Since no representative from Manipur was present, the status could not be updated.

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d) LILO of 132 kV Dimapur (Nagaland) – Kohima (Nagaland) line at 220/132 kV Dimapur (PGCIL) Substation- [Since Aug’11]:

Before Modification After Modification During 93rd OCC meeting, the subcommittee had suggested DoP, Nagaland to utilize the LILO arrangement at GIS substation at Dimapur for the connectivity to Kohima. The EE, SLDC,Nagaland informed that the CB of GIS bay tripped on 6th

February 2014 while the line was operating through LILO arrangement. The DGM POWERGRID informed that the problem with the CB of GIS bay would be rectified by 20th February 2014 and requested Nagaland to use the LILO arrangement at Dimapur GIS substation of POWERGRID. Nagaland agreed.

During the 95th OCC meeting, DGM, POWERGRID had informed that the project proposal for suggested modification (i.e. incorporation of additional Box Cross Arm at Tower Location No. 5) has been approved by competent authority of POWERGRID with following condition.

“Normal arrangement should be as per approved and implemented scheme i.e. Dimapur (PG) – Dimapur (State) 132kV S/C and Dimapur (PG) – Kohima 132kV S/C. Only during contingency at Dimapur (PG), it may be operated as Dimapur (State) – Kohima 132kV S/C.”

The communication in this regard has already been issued, vide letter No. NESH/OS/F-1004/475 dated 25-02-2014, addressed to EE, Electrical Transmission division, DoP, Govt. of Nagaland.

During 96th OCC meeting, EE, DoP, Nagaland informed that they have no

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objection to the arrangement suggested by POWERGRID. The work associated with above modification will be taken up soon and the work is likely to be completed by May 2014. Since no representative from Nagaland was present, the status could not be updated.


C.5 CT Ratio of Transmission Lines in NER:

For determining present loadability limits of Transmission lines of NER (132 kV & above), all constituents are requested to send the following details of CTs at both ends of their lines at the earliest: Present Setting of CT Ratio & PSM Setting (for protection) and CT specification.

It was discussed during 90th, 91st, 92nd, 93rd and 94th OCCMs that the data to be provided at the earliest.

TSECL, Me. PTCL, Nagaland, POWERGRID & NEEPCO (Kopili) have furnished these details. However other utility (NEEPCO, MSPCL, Mizoram, Arunachal Pradesh & NETC) have not furnished these data till date.


NERLDC informed that the details of CTs have been received from Tripura, Meghalaya and Nagaland. The representative of Assam informed that the details of CTs were submitted during 96th OCC meeting. The subcommittee requested Assam to resubmit / mail to NERLDC. NEEPCO informed that details of CT for the remaining stations have already been sent to NERLDC. CE, Ar. Pradesh stated that the details of CT will be furnished by May, 2014. The subcommittee requested others to submit the CT details to NERLDC at the earliest.

The subcommittee noted as above.

C.6 Furnishing Geographic Co-ordinates of Nodes of NER Grid:

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Power Maps of NER states are being developed by CBIP. To represent nodes of NER Grid in power maps, Co-ordinates of existing Nodes, Nodes under construction & identified future Nodes (66 kV & above) of NER Grid are required. Power Utilities of NER are requested to furnish latitude & longitudes of Nodes of NER Grid.

During the 96th OCC meeting, all the constituents have agreed to furnish the above data to NERLDC at the earliest. However, no data from any power utility have been received till date.


Ar. Pradesh & Tripura stated that the above data will be furnished by May, 2014. Assam and Meghalaya informed that the above data will be furnished by June, 2014.

The forum requested POWERGRID to help in getting latitude and longitude of stations of NER grid. DGM, NERTS stated that POWERGRID can help the constituents by providing the GPS equipment and the concern person of the constituents can co-ordinate with in-charge of nearby substation of POWERGRID.

The sub-committee requested the constituents to tie up with POWERGRID in this matter so that data as required by NERLDC can be furnished at the earliest.

The subcommittee noted as above.

C.7 Monthly MU requirement & availability of each state of NER as per format:

The following figures of state wise MU requirement and availability were taken from LGBR 2014-15 of NERPC. State wise MU requirement and availability for these months are to be checked. Constituents may kindly verify if the above data are correct.

Requirement:Name of State May14 Jun14 Jul14 Aug14 Sep14

Ar. Pradesh 50 57 61 62 64Assam 605 645 725 735 715

Manipur 48 49 59 59 61Meghalaya 165 145 160 150 145Mizoram 36 36 39 37 35

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Nagaland 56 54 60 50 60Tripura 110 105 120 120 125NER 1070 1091 1224 1213 1205

Availability:Name of State May14 Jun14 Jul14 Aug14 Sep14

Ar. Pradesh 51 62 79 74 65Assam 484 554 655 666 614

Manipur 59 66 85 87 79Meghalaya 174 211 279 222 250Mizoram 42 47 56 50 42Nagaland 36 47 58 62 55Tripura 160 164 180 180 185NER 1006 1151 1403 1341 1290

• These data required for preparation of various reports.

Constituents may kindly note.

C.8 Monthly MW requirement & availability of each state of NER:

The following figures were taken from minutes of 96th OCCM. These figures are to be reviewed.

A. Peak Demand in MWName of State May14 Jun14 Jul14 Aug14 Sep14

Ar. Pradesh 109 120 121 90 139Assam 1350 1400 1400 1400 1350

Manipur 120 110 125 110 135Meghalaya 300 320 300 260 310Mizoram 75 80 85 85 86Nagaland 100 110 105 110 100Tripura 240 250 240 250 260NER 2254 2390 2358 2345 2380

B. Peak Availability in MW

Name of State May14 Jun14 Jul14 Aug14 Sep14Ar. Pradesh 110 130 130 100 101

Assam 950 1200 1200 1050 1045Manipur 130 130 130 90 122

Meghalaya 280 300 320 350 401Mizoram 80 85 90 95 91Nagaland 95 95 95 100 95Tripura 200 210 230 260 300

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NER 1865 2200 2235 2045 2155

As decided in 96th OCCM, SLDCs are requested to provide the following data:-

A. Off Peak Demand in MW (0800 Hr)

Name of State May14 Jun14 Jul14 Aug14 Sep14Ar. Pradesh

AssamManipur

MeghalayaMizoramNagalandTripuraNER

B. Off Peak Availability in MW (0800 Hr)

Name of State May14 Jun14 Jul14 Aug14 Sep14Ar. Pradesh

AssamManipur

MeghalayaMizoramNagalandTripuraNER

Constituents may kindly note.

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D. N E W I T E M S

D.1 Generation Planning (ongoing and planned outages)

NEEPCO/NHPC/OTPC may kindly intimate the availability for hydro stations:

Khandong – 0.390MU Kopilli – 30.46 MURanganadi - Subject to inflow Doyang – 4.05 MULoktak – 1.95 MU

After detail discussion the sub-committee approved the shutdown as proposed by OTPC, NEEPCO & NHPC for April, 2014 to May 2014 as given below:

S.N Unit No: From To No. of days Reason

1. OTPC #118.05.201

424.05.201

47 days PG Test

2. AGTPP U#210.05.201

416.05.201

47 days HGPI ???

3. Loktak U#306.05.201

410.05.201

45 days APM

The Sub-committee enquired from NEEPCO about the status of ongoing outage units of Kopili & Khandong HEPs.

NEEPCO informed that Kopili U#1 will be put back in service by 15.05.2014, Khandong U#1 & Kopili Stage –II by end of May, 2014 and Kopili U#2 by end of June, 2014.

Committee noted as above.

D.2 Outage Planning Transmission elements

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During 96th OCC meeting, the representative of Assam had informed that the planned shutdown of Bongaigaon – Binaguri 400kV D/C line was approved by OCC forum upto 17:00hrs. But NLDC extended the shutdown of the above line upto 24:00Hrs restricting TTC/ATC in NER – ER corridor. The reason behind extension of shutdown beyond 17:00Hrs upto 24:00Hrs by NLDC is not clear. This had created problems for the utilities to meet power demand during peak hours, particularly during this lean hydro season. Other constituent states of the region were also of same view.

The subcommittee had requested NERLDC to take up the matter with NLDC highlighting the constraints and difficulties being faced by the utilities due to such action of NLDC. Also the sub-committee has requested NERPC to take up this matter with NPC.

After detail discussion the sub-committee approved the shutdown as proposed by POWERGRID, ENICL & Assam (AEGCL) for May, 2014 to June 2014 as given in Annexure – D.2.

D.3 Power supply to Rural Villages:

Month & Year:

Name of the State

Number of Distribution Companies in the State

Name of Distribution Company

Total Electrified villages Average Hours of Power Supply to rural areas in the month (Hours)

Energy supplied to Rural Areas during the month (MU)

Total No. of

inhabited villages as per 2011 census

No. of inhabited villages

Electrified


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SE(O) informed that even after repeated request, only Assam, Tripura and Mizoram have submitted the required information for last three months [January, February, and March 2014] in above simplified format. Ministry of Power and CEA are insisting for submission of above information on monthly basis. He requested all constituent states of NER to submit required information for last four months [January, February, March, and April 2014] in above format and information for subsequent month may please be submitted on monthly basis.

The Committee noted as above.

D.4 LGBR for 2014 - 2015:

SE (O) informed that the LGBR for 2014 -15 for NE Region is yet to be finalized. He requested all the constituents to submit the data for preparation of LGBR at the earliest as per the proforma already circulated to them. He also informed that maintenance schedule / the outage planning of the Generating units, important ISTS lines as well as important transmission elements in state and central sector should be furnished by the constituents.

He further informed that NERPC has prepared the draft LGBR regarding the demand and availability in MWs & MUs for 2014-2015.

Constituents were requested to check the draft LGBR and submit the above data in the format furnished by NERPC at the earliest.


D. 5 Furnishing Energy Charge Rate (ECR) of NER ISGS:

NERLDC informed that for merit order dispatch, Energy Charge Rates (ECR) of Palatana, AGBPP, AGTPP, Ranganadi, Kopili, Khandong, Kopili St II, Doyang and Loktak are required. NEEPCO, NHPC & OTPC are requested to furnish Energy Charge Rates (ECR) of previous month in ₹/kWh by 15th.


The Sub-committee requested all the concerned utility [OTPC, NEEPCO, NHPC] to furnish the Energy Charge Rates (ECR) of previous month in respect of each generating station to NERLDC by May, 2014. As Requisition based scheduling has already been implemented in NER, this information is required by constituent

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states of the region for requisition of their demand from different generating stations while submitting their schedule to NERLDC.


D.6 Pre monsoon activity of transmission elements:

NERLDC informed that it was observed that number of tripping of transmission elements in NER increased during monsoon period of last year. For minimization of tripping transmission elements in NER, it is requested to complete all activities (like trimming of trees, vegetation issues etc) of transmission elements before monsoon.


The Sub-committee requested all the constituents/utility to carry out the above activities as suggested by NERLDC.The Committee noted as above.

D.7 Up-dated List of important Grid Elements May 2014 document (Draft):

NERLDC informed that as per Clause No 5.2.c of IEGC, List of Important Grid Elements was prepared. Updated List of Important Grid Elements May, 2014 (Draft) was e-mailed to regional entities of NER and also available in our website.

It is requested to furnish data required for finalization of List of Important Grid Elements May 2014 by 25th May’12. This document will be finalized by 28th

May14.


The Sub-committee requested all the constituents/utility to look into the matter and take necessary action. The details available in the website of NERLDC show that very few information (highlighted in yellow colour) are to be provided by the constituents. The required data and comments/observations should be furnished to NERLDC at the earliest.The Committee noted as above.

D.8 Furnishing of Technical and Commercial Data for computation of PoC charges & Losses for July – September, 2014:

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Designated ISTS Customers (DICs) are requested to submit the data for New Transmission Assets, Yearly Transmission Charges (YTC), Forecast Injection and Withdrawal and Node-wise Injection/Withdrawal data as per Format I, Format II & Format III (Formats are available in NLDC website ) to the Implementing Agency (NLDC, POSOCO) along with copy to NERLDC for computation of PoC Charges and Losses for Jul-Sep14 at the earliest. Soft copy of these filled up formats are also to be sent to the Implementing Agency (NLDC, POSOCO) along with copy to NERLDC at the earliest. Letter for submission of these data as per formats was e-mailed to all DICs on 30.04.14.


The Sub-committee requested all the constituents/utility to look into the matter and take necessary action. The required data and comments/observations should be furnished to NERLDC at the earliest.The Committee noted as above.

D.9 Restoration Procedure of NER States:

NERLDC have published the restoration procedure of NER Grid on November, 2013. As per IEGC clause 5.8(b) each state shall be prepared its own restoration procedure. Therefore, States are requested to submit their restoration procedure to NERLDC for necessary modification in the existing procedure.


The representative of Meghalaya informed that the restoration / black start procedure has already been uploaded in their website. The representative of Tripura informed that the restoration / black start procedure will be submitted very soon. The Sub-committee requested all the constituents/utility to look into the matter and take necessary action. The restoration procedure prepared by them should be furnished to NERLDC at the earliest.The Committee noted as above.

D.10 Frequent tripping and long outage of Pallatana generation:

EE, SLDC, Me. ECL has intimated that at present they are having a share of 10.88% (about 36 MW) from Pallatana Gas based power station. During the month of April there were 7 times tripping of Pallatana generation. Due to

21


tripping of Pallatana, Me. ECL scheduled drawal was reduced by 35 MW. Such sudden reduction in the scheduled drawal by about 50% resulted in sudden overdrawal; which has to be compensated by emergency load shedding to avoid overdrawal and subsequent penalty due to violation of grid code. But such huge load shedding has caused lots of inconveniences to the consumers as the ongoing scheduled load shedding is going on throughout the state.


The Sub-committee expressed concern about the long outage of Pallatana as occurred from 04.01.2014 to 14.02.2014 which affected the availability of power especially during the lean season. Moreover, the frequent tripping of the unit has not only brought inconveniences to the consumers but also has caused huge commercial loss to the constituents in form of penalty as per deviation settlement mechanism.

Sr. Mgr, TSECL stated that the matter has been taken up to with CERC and outcome / order in this regard is awaited.


D.11 Pallatana generation:

Sr. Mgr, TSECL informed that on 1st May 2014, Palatana Generation was around 160 MW during peak hours. But schedule given to the beneficiary was not as per allocated percentage. Same was repeated on 2nd May, 2014. He requested NERLDC to deliberate in the matter.


NERLDC stated that the issue raised by them has already been taken care by them as per the guidelines of CERC and the benefit goes to the state utilities. The subcommittee requested TSECL to provide the details of transactions on these days to NERLDC and discuss with NERLDC. If required, the matter can be discussed further in next OCC meeting.


D.12 Discrepancy in Scheduled vs Actual in NERLDC website in respect of Ar. Pradesh:

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CE, Ar. Pradesh informed that they have been observed from the NERLDC website that the over drawl figures of A.P is erroneous. He stated that power is drawn by Ar. Pradesh from NER & ER at various inlet points. In the absence of proper recording devices viz., RTU in many of those points, actual energy drawn is assessed on a lump sum basis. It is understood that some power is added manually to connect A.P and Assam at Distribution and sub-distribution level which does not have RTUs. Such inlet points are: Rupai-Namsai, Lekhapani-Jairampur, Salkatani-Kanubari, Silapathar-Likabali, Jonai-Pasighat, Rowta-Balemu, Jamuguri-Seijousa, Silapathar-Dipa and Digboi-Bordumsa.


GM, APDCL stated that Ar. Pradesh is drawing power from Assam at 33kV or 11kV level at about 11 to13 locations. He informed that Assam has now installed SEMs at these drawal points, the actual power drawn by them can be calculated.

CE, Ar. Pradesh further stated that since SCADA/SLDC is not yet in place, the real time data is not available. He mentioned that data collected on monthly or quarterly basis in 96 time blocks can be furnished by them and NERLDC can assess the average peak and off-peak drawal. There is wide variation in drawal shown in the webpage of NERLDC and actual drawal. NERLDC agreed with the concern of Ar. Pradesh. Subcommittee suggested that the average of off-peak and peak drawal by Ar. Pradesh may be observed over a period of time. The weighted average of off-peak and peak drawal by Ar. Pradesh may be considered for calculation purpose and accordingly the various messages relating to drawal may be issued by NERLDC till fully functional SLDC / SCADA system is put in place in Ar. Pradesh.

After detail discussion, the Sub-committee requested Ar. Pradesh & Assam to resolve the commercial matter bilaterally as far as energy transaction is concerned.


D.13 Information sharing and co-operation by all constituents:

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CE, DoP, Ar. Pradesh stated that since there is no functional SCADA system in the state of Ar. Pradesh, requisite data for control and monitoring by the SLDC, Itanagar has to be manually collected from various stations over available communication link viz. Telephone and the internet. Some of the major sub-stations are PGCIL Nirjuli, PGCIL Dilopoliyang, PGCIL Balipara, Kathalguri NEEPCO, Rupai, Jonai etc. He requested the above stations to be co-operative in sharing of data as and when sought for.

Committee may like to note.

D.14 Denial of Chinese Visa to Ar. Pradesh nominee for study tour:

CE, DoP, Ar. Pradesh stated that the recently concluded study tour to China conducted by NERPC with participants nominated from NER constituents was not satisfactory as far as Arunachal Pradesh is concerned. The denial of Chinese visa to the nominee from A.P was intimated by M/S Aviana Travels Ltd, Kolkata at the eleventh hour without giving any reasons which not only alienated and humiliated the nominee but also insulted the state of A.P as a whole. This study tour should have been either dropped or conducted in some other country. He requested NERPC Secretariat that such tour should be avoided in future.

The Sub-committee noted the view of Ar. Pradesh.

D.15 Estimated Transmission Availability Certificate (TAC) for the month of April, 2014.

The Estimated Transmission System Availability for the month of April, 2014, furnished by PGCIL, is 99.9820%. The detail outage data for calculation of Transmission System Availability furnished by PGCIL, is at Annexure D.15. NER constituents are requested to kindly communicate their views and observations, if any, by 27th May, 2014 so that Final TAC for the month of April, 2014 can be finalized by NERPC Secretariat.


E. N E W I T E M S

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E.1 Enhancement of SPS related load shedding:

NERLDC stated that it was observed that there was number of tripping of Palatana machines during Apr14. Due to tripping of Palatana machines, NER Grid was operated in vulnerable condition. Though, there was relief of around 40-50 MW(Off Peak) & 80-90 MW(Peak) after activation of SPS I. But it is not sufficient to operate NER Grid in safe, secure and reliable mode under this scenario. To operate NER Grid in safe, secure and reliable mode, it is required to enhance SPS related load shedding to 250 MW.


The representative of Assam did not agree with the view of NERLDC and strongly opposed the load shedding upto 250MW during the tripping of generating unit at Palatana. The sub-committee requested NERLDC to review the proposal so that the issue can be discussed further in the next OCC meeting.


E.2 Implementation of islanding scheme in NER

During the 94thOCC meeting, the committee had decided the following islanding scheme and associated frequencies levels for creation of islands in NER:

SN Islanding Scheme Lines required to be opened

UFRLocation

Implementing Agency

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ISLAND AT 48.80 Hz with 5 Sec delay: Island comprising of generating units of AGBPP (Gas), NTPS (Gas) & LTPS (Gas) and loads of Upper Assam system & Deomali area (Ar. Pradesh) [Total Generation: 380-400MW and load: 200MW (off peak)-300MW (peak)]

(a) 220 kV New Mariani (PG) – AGBPP

UFR-1[At New Mariani

(PG)]PGCIL

(b) 220 kV Mariani – Misa UFR-2

[At Mariani, Samaguri of

AEGCL]

AEGCL(c) 220 kV Mariani – Samaguri(d) 132 kV Mokukchung – Mariani(e) 132 kV Dimapur (PG) – Bokajan

UFR-3[At Dimapur

(PG)]PGCIL

(f) Generators to be desynchronized for reduction of generation [if Generation > Load in

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the islanded pocket]

(g) De-synchronization / isolation of one GT and one ST from each of two modules of AGBPP, which are in operation, leading to reduction of generation of about 80-90 MW [i.e each module will contribute to reduction of about 40-45 MW (GT:30MW+ST:15MW)].

At AGBPP[UFRs of

line bays & Generator to be

used]

NEEPCO

(h) Lines required to be opened for load shedding of 30MW (off-peak) and 50MW (peak)[if load > generation in the islanded pocket](i) 132kV Tinsukia – Ledo S/C line (at 48.7Hz instantaneous). UFR [At

Tinsukia]AEGCL

(j) 66kV Tinsukia – Rupai S/C line (at 48.6Hz instantaneous)

AEGCL

(k) 132kV Jorhat – Bokakhat line (at 48.5Hz instantaneous)

UFR [At Jorahat /

Bokakhat]AEGCL

2 2

ISLAND AT 48.50 Hz with 5 Sec delay : Island comprising of generating units of AGTPP (Gas), generating units at Baramura (Gas), Rokhia (Gas) & Gumati (Hydro) and loads of Tripura system & Dullavcherra area (Assam) [Total Generation: 150-160MW and load: 110MW (off-peak) &170-180MW (peak)]

132 kV Palatana – Udaipur UFR-1[At Palatana] OTPC

132 kV Palatana – Surjamani Nagar

132 kV Silchar – Dullavcherra

UFR-2[At Silchar] PGCIL

132 kV AGTPP – Kumarghat

UFR-3[At Kumarghat] PGCIL132 kV P K Bari –

Kumarghat

3 3 ISLAND AT 47.90 Hz: Isolation of NER from NEW grid at ER-NER boundary with rest of

To be decided after system study

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the generation and load of NER

Both the Islanding schemes were implemented as discussed in OCC/PCC forum and it was decided that two UFRs (one as back up) are to provided for disconnection of lines as well as generators. Further subcommittee had suggested for use the UFR of the generators as back up for de-synchronization of Gas Turbine (s) and for developing the logic to identify the Units, which are in service / operation so that these modules are de-synchronized/ isolated from the system in order to achieve the load and generation balance and to activate the Automatic Governor Control of each module. It was also decided that in future, in case any problem arises, both islanding schemes will reviewed and modified as per system requirement.

During 96th OCC meeting, DGM, NERLDC had informed that during the grid disturbance in NER on 19-03-2014, it has been observed that none of the islanding scheme (including islanding scheme associated with NTPS) had worked as expected although the frequency had gone below 48.5 Hz and even persisted for more than 5 sec. Subcommittee felt the need for reviewing the schemes and to discuss about the deficiency in the scheme. The malfunctioning of protection system was also brought to the notice by NERLDC.

After discussion in 96th OCC meeting, it was decided to form a subgroup [Operation and Protection sub-group] with NERPC as Convener to discuss following issues:

(a) grid disturbance in NER in detail(b) improvement / modification required in existing islanding schemes / SPS (c) addition of new islanding schemes / SPS as per system requirement(d) other important issues relating to Protection system / Grid Disturbance /

failure of major equipment in NER (e) and to suggest remedial measures.


MS I/C informed that the first meeting of subgroup was held in the conference hall of NERLDC at Shillong on 11.04.2014 taking representation from Assam, Meghalaya, POWERGRID, NEEPCO, NERLDC and NERPC. It was also decided to

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include representation from other states / organization as and when required / depending on the interest shown by the organization. The following officers were nominated for the 1st meeting of the subgroup:

Assam: Sh. Gunajit Bhuyan, AGM (MRT) & Sh. Ashutosh Bhattacharji, MgrMeghalaya: Sh. F.E. Kharshiing, SE, SLDC & Sh. H. Shangpliang, EE (MRT)PGCIL: Sh. P. Kanungo, DGM, Sh. M. Madhavan, Mgr & Sh. Supriya Paul, ErNEEPCO: Sh. Tanya Taji, Sr. Mgr & Sh. Jaypal Roy, Mgr.NERLDC: Sh. P.P. Bandapodhyay, DGM & Sh. A. Mullick, CMNERPC: Sh. B. Lyngkhoi, SE(O) and Sh. S.M. Jha, EE(O)

OTPC has requested to include Shri S.R. Das as their nominee for the subgroup.

In the meeting of Operation and Protection sub-group, it was brought to the notice that most of UFRs associated with two islanding schemes operated as expected and it was decided to reduce the time delay setting of UFR to 2 secs (in place of 5 sec). Assam had informed that there is some change in load connected with NTPS and subgroup had requested Assam to provide details of connected load. Assam & NEEPCO was also requested to intimate about the low frequency setting for tripping of Gas based Generators at NTPS (of Assam), at AGBPP & AGTPP (of NEEPCO) and to intimate frequency at which machines at NTPS, AGBPP & AGTPP tripped on 19-03-2014 so that the matter can be discussed further.

During the meeting the DGM, POWERGRID suggested to reduce the time delay setting of UFR to 500ms instead of 2 secs as proposed in last subgroup meeting. The subcommittee felt that following information should be collected before deciding about the final setting of UFRs.

(a)Operation of UFRs, installed on various lines associated with the particular Island, on 19-03-2014 [i.e { UFRs at New Mariani, Dimapur of Powergrid; UFRs at Mariani, Samaguri of AEGCL and UFRs at AGBPP associated with Islanding Scheme –I (at 48.8 Hz) } and { UFRs at Silchar, Kumarghat of Powergrid; and UFR at Palatana of OTPC associated with Islanding Scheme –II (at 48.5 Hz) } ]

(b)Operation of UFRs, installed on various lines associated with the particular Islanding Scheme –I (at 48.8 Hz), on 19-03-2014 [i.e UFRs at Tinsukia, Jorahat / Bokakhat of AEGCL]

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(c) Whether carrier inter-tripping (wherever available) functioned as expected?(d)Operation of frequency relays of generators at AGBPP (NEEPCO), NTPS

(AEGCL), LTPS (AEGCL) on 19-03-2014 and frequency at which generating Unit (s) tripped

(e) Time delay setting low frequency relays of generators at AGBPP (NEEPCO), NTPS (AEGCL), LTPS (AEGCL)

(f) Operation of frequency relays of generators at AGTPP (NEEPCO), Baramur (TSECL), Rokhia (TSECL) and Gumati (TSECL) on 19-03-2014 and frequency at which generating Unit (s) tripped

(g) Time delay setting low frequency relays of generators at AGTPP (NEEPCO), Baramur (TSECL), Rokhia (TSECL) and Gumati (TSECL)

(h) Whether generating Units tripped due to operation of UFRs of line (s) or due to operation of frequency relay of generating unit or due to some other reason.

(i) Number of generating unit (s) tripped at the station on 19-03-2014.(j) The details of load connected with NTPS and LTPS on 19-03-2014 and

maximum load connected with NTPS & LTPS (k)Why the NTPS could not survive with its own load? This has happened in past

in many occasions, even during last major grid disturbance on 31st July 2013 NTPS survived with its own connected loads.

(l) Any other information which the generating company (ies) would like to share with the forum which has relevance with the proposed islanding scheme.

The subcommittee also requested all constituent states of the region to provide details of UFR operation [i.e. location, frequency at which UFRs operated / frequency setting of UFRs and the quantum of load shedding happened due to operation of UFRs] on 19-03-2014.

The subcommittee felt that due to isolation of NER grid from National grid on the day of the incidence (i.e. 19-03-2014), the power number become very small [reduced to about 30-40MW/Hz from 3000-3400MW/Hz when it was in synchronism with National grid] and hence the rate of fall of frequency might have been fast. Under such scenario, only UFRs may not serve the objective. There could be requirement of df/dt relays along with UFRs. System studies would definitely help to arrive at some conclusion. But in absence of adequate information about the old machines in the islanded pocket, it has become difficult

29


to carry out system studies. Although Prof. P. Tripathi of IIT, Guwahati was requested to help in this regard, but no progress has happened in this direction so far. In view of all these difficulties the sub-committee suggested that after receiving above information from Assam, NEEPCO, TSECL and constituent states of the region, the subgroup would meet again to study / investigate the matter and decide further course of action. The Committee noted as above.

E.3 Major Events in North Eastern Regional Grid during April, 2014:

NERLDC informed that there were a number of Grid Disturbances in NER of Category III and above, which have resulted in substantial load/generation loss in Southern part of NER Grid during April, 2014.

The Sub-committee also discussed in detailed on the following incidences as given below:

1. Category IV Grid Disturbance occurred in NER on 08.04.2014:

At around 2204 Hrs, 400 kV Silchar – Byrnihat line (carrying 163 MW) tripped (132 kV Khliehriat – Badarpur had tripped earlier at 2201 Hr). This resulted in overloading & subsequent tripping of 132 kV Haflong – Jiribam line. This again caused overloading & subsequent tripping of 132 kV Loktak – Ningthoukhong & 132 kV Loktak – Imphal lines. Due to tripping of this lines, Southern Part of NER Grid comprising of South Assam(except Haflong & Umrangso Load), Manipur (except Imphal load), Mizoram & Tripura separated from rest of NER Grid and subsequently at 22:05 Hrs GTG I & STG I of Palatana tripped triggering the operation of SPS I. However, Southern part of NER Grid collapsed due to load generation imbalance.

Generation Loss: 517 MW (58 MW: AGTPP, 330 MW: Palatana, 23 MW: Loktak & 106 MW: TSECL)

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Load Loss: 335 MW (46 MW: MSPCL, 48 MW: Mizoram, 196 MW: TSECL & 45 MW: South Assam)

2. Category III Grid Disturbance occurred in NER on 19.04.2014: At around 1400 Hrs, 400 kV Silchar- Byrnihat line, 400 kV Silchar- Palatana I & II and GTG I & STG I of Palatana tripped. Tripping of Palatana machines triggered the operation of SPS I. Further at 1404 Hrs 400/132 kV, 125 MVA ICT at Palatana, 132 kV Palatana- Udaipur and 132 kV Palatana- Surjamaninagar lines tripped resulting in loss of part of Tripura Load. It may be noted that Auto-Reclose operated successfully at Byrnihat end of 400kV Silchar- Byrnihat line but did not operate at Silchar end.

Generation Loss: 320 MW (Palatana)Load Loss: 66 MW (46 MW: South Assam, 20 MW: Tripura)

3 Category IV Grid Disturbance occurred in NER on 26.04.2014: At around 0551 Hrs, 400 kV Silchar - Palatana I, GTG I & STG I of Palatana, Unit 1, 2 and 4 of AGTPP, 132 kV Silchar - Badrpur I & II, 400/132 kV, 2x200 MVA, ICT I & II at Silchar tripped. Tripping of Palatana machines triggered the operation of SPS I.

Generation Loss: 383 MW (58 MW: AGTPP & 325 MW: Palatana)Load Loss: 50 MW (South Assam)

4. Category III Grid Disturbance occurred in NER on 28.04.2014: At around 0007 Hrs, 400 kV Silchar- Palatana I tripped. 400 kV Silchar- Palatana II and GTG I & STG I of Palatana tripped at 0008 hrs. Tripping of Palatana machines triggered the operation of SPS I. At 0035 Hrs, 400 kV Silchar- Byrnihat line tripped. 132 kV Khandong- Haflong line tripped at 0048 Hrs and 132 kV Khliehriat- Badarpur line tripped at 0053 Hrs. This lead to tripping of 132 kV Dimapur- Imphal line on over current at 0059 Hrs. Due to these trippings, power supply was interrupted in 132 kV pocket comprising of Mizoram, Part of South Assam and Part of Manipur. Tripura was running in isolation with AGTPP machines.Generation Loss: 345 MW (320 MW: Palatana & 25 MW: AGTPP)Load Loss: 139 MW (40 MW: Manipur, 39 MW: Mizoram & 60 MW: South Assam)

5. Category III Grid Disturbance occurred in NER on 29.04.2014:

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At around 2015 Hrs, 400 kV Silchar - Palatana I and GTG I & STG I of Palatana tripped. Tripping of Palatana machines triggered the operation of SPS I.

Generation Loss: 320 MW (Palatana)Load Loss: 91 MW (South Assam)

B. Palatana Module I Tripping: At 0128 Hrs on 03.04.14, Palatana STG- I tripped. Due to this tripping there was a generation loss of 116 MW.

At 0843 Hrs on 04.04.14, Palatana GTG- I tripped. Due to tripping of GTG-I , STG- I also tripped. There was a generation loss of 302 MW (GTG I- 195 MW & STG I- 107 MW)

At 0442 Hrs on 07.04.14, Palatana GTG- I tripped. Due to tripping of GTG-I, STG- I also tripped at 0511 Hrs. There was a generation loss of 320 MW (GTG I- 207 MW & STG I- 113 MW)

At 1047 Hrs on 12.04.14, Palatana GTG- I tripped. Due to tripping of GTG-I, STG- I also tripped. Tripping of Palatana machines triggered the operation of SPS-I resulting in load relief of 45 MW in South Assam area. There was a generation loss of 330 MW.

At 0611 Hrs on 19.04.14, Palatana GTG- I tripped. Due to tripping of GTG-I , STG- I also tripped. Tripping of Palatana machines triggered the operation of SPS-I resulting in load relief of 40 MW in South Assam area. There was a generation loss of 245 MW.


The subcommittee expressed concern for frequent tripping of Palatana-Silchar 400kV line along with the Generating Unit of OTPC and tripping of Byrnihat - Silchar 400kV line. The DGM, POWERGRID informed the house that during patrolling of Palatana-Silchar 400kV line, the clearance problem between ground wire and conductor was noticed in some section of line and the same has been resolved by increasing tension in earth wire. During thermal scanning, hot spots were observed at loose connection points, particularly at jumper locations. The tightening of jumpers at such locations has been taken up and work will be completed very soon. But he emphasized that tripping of one circuit should not cause tripping of Generating Unit and the other available circuit is capable of

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carrying more than 500MW. Moreover, Single Phase Auto Reclosing (SPAR) operation should not lead to tripping / outage of machine at Palatana. The subcommittee requested OTPC to look into these matters seriously as tripping of line should not lead to outage of generating Unit. Moreover, the tripping of the unit not only brings inconveniences to the consumers but also has huge commercial impact in form of penalty as per deviation settlement mechanism. There should be proper co-ordination in relay setting of generating Unit and the associated transmission line. The subcommittee requested OTPC to resolve the issue in consultation with BHEL and POWERGRID before the Unit is taken for PG test. The subcommittee also requested OTPC to discuss with BHEL about the low voltage problem leading to tripping of 6.6kV motors. The details of discussion / findings may please be brought to the notice of the subcommittee for further discussion in the next OCC/PCC meeting.

C. Disturbance in Manipur System :

At 0812 Hrs on 12.04.14, 132 kV Imphal (PG) – Imphal I and II lines tripped. Due to tripping of these elements, power supply to Imphal area of Manipur was interrupted.Load Loss: 65 MW Generation Loss: 8 MW (Loktak)

At 0550 Hrs on 23.04.14, 132 kV Imphal(PG) – Imphal I and II lines tripped. Due to tripping of these elements, power supply to Imphal area of Manipur was interrupted.Load Loss: 60 MW

D. Disturbance in Meghalaya System:

At 1345 Hrs on 29.04.14, 132 kV Khleihriat (PG) - Khleihriat I & II lines tripped. Due to tripping of these elements, power supply to Khliehriat area of Meghalaya was interruptedLoad Loss: 33 MW

At 2210 Hr on 29.04.14, 132 kV Khandong - Khliehriat I, 132 kV Kopili- Khandong II, 132 kV Khliehriat (PG) - Khliehriat I & II lines tripped. Due to tripping of these elements, power supply to Khliehriat Area of Meghalaya interrupted.

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Load Loss: 28 MW

E. Major Events in North-Eastern Regional Grid:

List of multiple tripping of elements and tripping of important elements in North-Eastern Regional Grid during the period w.e.f. 01st April, 2014 to 30th April, 2014 are enclosed at Annexure - E along-with (Letters for Furnishing Event information on weekly basis are being sent to the power utilities of NER by e-mail w.e.f 13th January, 2014. Constituents are requested to furnish details of tripping reported in the letters.


Any other item:

1. Status of funding from NLCPR-Central for “ Rectification of various deficiencies including renovation and modernization of protection system in existing substations and Generating stations of 132kV and above voltage class”

Member Secretary (I/C) informed that the consolidated project proposal, amounting to about Rs. 816 crores, for “Rectification of various deficiencies including renovation and modernization of protection system in existing substations and Generating stations of 132kV and above voltage class”, prepared by NEPRC in consultation with seven states of North Eastern Region (NER), was submitted to Hon’ble Union Minister of State, Govt. of India and Hon’ble Minister of DONER by Chairman, NERPC and Hon’ble Minister of Power (Govt. of Tripura) in the month of January 2014, for funding through NLCPR-Central. The project proposal has also been examined by CEA. But Director (Transmission), Ministry of Power, Govt. of India has informed that at present fund is not available in NLCPR (Central) and the process may take long time for approval. Hence he has advised to get funding from PSDF. The modality for release of money from PSDF is under finalization. Once it is finalized, each constituent states of the region may submit the project proposal separately to NLDC / Appraisal committee of PSDF for getting financial support for implementation of the scheme.

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2. NEEPCO informed that due to partial requisition by the beneficiaries like Assam and Tripura from AGBPP, it becomes difficult to increase the generation in peak hours commensurate with the requirement or follow the schedule. NEEPCO requested NERLDC to look into the matter so that stable load schedule is provided to AGBPP for steady gas drawal from OIL, otherwise it would be very difficult to receive the required quantum of gas from OIL during the time of need.

NERLDC stated that generating companies have been requested many times to provide the ramp up/down rate etc., but till now no response has been received from Generating companies.

NEEPCO stated that they have already furnished the above information to NERLDC. However, the sub-committee requested NEEPCO to furnish above information once again to NERLDC. The matter will be discussed further, if any problem is encountered in future.


Date & Venue of next OCC meeting

It is proposed to hold the 98thOCC meeting of NERPC on 10th June, 2014 (Tuesday). However, the exact date and venue will be intimated in due course.

The meeting ended with thanks to the Chair.

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

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Annexure-I

List of Participants in the 97 th OCC & 21 st PCC Meetings held on 06/05/2014

SN Name & Designation Organization Contact No.1. Sh. Anong Perme, CE (P), TP&MZ Ar. Pradesh 094360402972. Sh. Tarik Mize, EE, SLDC Ar. Pradesh 094362886433. Ms. Oyi Nesi, AE, SLDC Ar. Pradesh 094366292994. Sh. J.K. Sharma, CGM, SLDC Assam 094355594475. Sh. M.K. Adhikary, GM (TRC) Assam 098640492876. Sh. B.C. Bordoloi, GM (Gen) Assam 094350456257. Sh. Sanjib Goswami, OSD to Minister Assam 098640350958. Sh. A. K. Saikia, DGM, SLDC Assam 098641161769. Sh. J.K. Baishya, AGM, L.DISCOM Assam 09435041494

10. Sh. K. Goswami, AGM, APDCL Assam 0986402001911. Sh. M.B. Choudhury, AGM (Gen) Assam 0943504877512. Sh. A. Choudhury, AGM (HQ) Assam 0986410233213. Sh. A.K. Das, AGM (HQ) Assam 0943504580414. Sh. A. Bhattacharji, Dy. Mgr (Prot) Assam 0943533292815. Sh. B. Bordoloi, Dy. Mgr (Prot) Assam 09435558343

No Representative Manipur16. Sh. T. Gidon, EE, SLDC Meghalaya 0977447995617. Sh. S. Saha, AE, PLCC Meghalaya 0943611279818. Sh. Ratan Debbarma, DGM, Tripura 0943613096019. Sh. Debrata Pal, SM (Comml.) Tripura 0943650024420. Sh. N.J. Gogoi, Sr.Mgr (E/M) NEEPCO 09435339693

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21. Sh. P.K. Choudhury, Dy. Mgr (O&M) NEEPCO 0943534391622. Sh. Anupam Kumar, Sr. Engr. NERLDC 0943633537923. Sh. Rahul Chakrabarti, Engr. NERLDC 0940250754324. Sh. P.Kanungo, DGM (OS) NERTS 0943630282325. Sh. Pranav Kumar, Engr. NHPC 0943689488726. Sh. R.K. Tenzing, Engr. NHPC 0943689488527. Sh. Mukul Banerjee, GM (Plant) OTPC 0841399076628. Sh. S. R. Das, Mgr. (E) OTPC29. Sh. S.K. Mondal, Sr. Officer ENICL 09773337643030. Sh. S.K. Ray Mohapatra, MS I/C NERPC 0981852785731. Sh. B.Lyngkhoi, S.E (O) NERPC 0943616341932. Sh. S.M. Jha, E.E (O) NERPC 09831078162

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Documents

97th OCC 21st PCC Minutes Final 16.05.2014