83rd OCC Minutes Final

8/13/2019 83rd OCC Minutes Final

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North Eastern Regional Power Committee

MINUTES OF THE 83rdOPERATION COORDINATION SUB-COMMITTEE MEETING

OF NERPC

Date : 11/03/2013 (Monday)

Time : 10:30 hrs

Venue : The Classic Hotel, Imphal, Manipur.

The List of Participants in the 83 rd OCC Meeting is attached at Annexure I

The meeting was started with welcome address by Shri D. Chattopadhyay, General

Manager (O&M), NHPC. He stated that NHPC is honored to host the OCC meeting of

NERPC in Imphal as per roster. He mentioned about the importance of OCC

meeting where issues relating to system operation and overall development of the

region is being discussed. He requested all the participants to actively participate in

the discussion for fruitful outcome of the meeting. He wished all the participants a

comfortable stay in Imphal and then requested Member Secretary I/C to proceed

with the meeting.

Shri S. K. Ray Mohapatra, Member Secretary I/C, NERPC welcomed the

participants and thanked NHPC for hosting the meeting and for making the

excellent arrangement for comfortable stay of delegates. He informed the house that

after grid disturbance on 30th and 31st July, 2012, efforts are being made at

different levels to implement various recommendations of the enquiry committee to

avoid re-occurance of such incidences in future and to maintain grid discipline for

smooth and safe operation of the grid. Further, he stated that Protection Audit has

been completed in February, 2013, the report highlighting the deficiencies in NER

system along with recommendations and implementation plan is likely to be

submitted by March 2013. He also informed that due to non-availability of

generation from the GBPP of OTPC at Pallatana, the region is facing acute shortage

of power during this lean hydro period although problem of evacuation of power

from the GBPP has been solved after commissioning of 400KV Silchar Byrnihat

line in February, 2013. He wished that the technical problem with the machine will

be resolved soon and the generation from the OTPC plant will be resumed at the


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Minutes of 83rd OCC meeting held on 11th March, 2013 at Imphal

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earliest for the benefit of the region. He requested constituents to co-operate with

NERLDC in real time operation for safe and secure operation of the grid.

Thereafter, Member Secretary I/C requested Shri B. Lyngkhoi, SE(O), NERPC to

take up the agenda items for discussion.

CONFIRMATION OF MINUTES OF 82 nd MEETING OF OPERATION SUB-COMMITTEE OF NERPC.

The minutes of 82nd meeting of Operation Sub-committee held on 7th February,

2013 at Shillong were circulated vide letter No. NERPC/OP/OCC/2013/2880-907

dated 15th February, 2013.

NEEPCO has requested for correction in the recording of minutes of 82nd OCC

meeting in respect of Item D.9 regarding RGMO installation in NEEPCO generating

stations. The status of Implementation of RGMO at NEEPCO Hydro Power Plants

as follows (AS ON 15.01.2013) on Item D.9 may be noted as below:

RanganadiHEP

3X135 MW

The type of Governor is G40. Existing EHG of the units are not

compatible for incorporating RGMO. Order for new microprocessor

based EHG incorporating restricted mode operation has already

been placed with the OEM, M/s BHEL on 30/03/2012.

Considering the lead time for delivery and transportation time, it

is expected that the system can be made operational in all units

by March, 2014 after erection/commissioning during lean hydro

season of 2013-14.

DoyangHEP-3X25MW

The type of Governor is G40. Existing EHG of the units are not

compatible for incorporating RGMO. Order for new microprocessor

based EHG incorporating restricted mode operation has already

been placed with the OEM, M/s BHEL on 10/10/2012.

Considering the delivery schedule of 8 months from date of order

& programming erection schedule during lean hydro season, it is

expected that the system can be made operational by March2014.

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


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Kopili

4X50 MW

The type of Governor is G40 in all the units of KHEP. Existing

Governors of the power Stations are not compatible for

incorporation of RGMO.

For 50 MW Unit-I & II of the Kopili Power Station, new Governor

system has been placed with OEM along with R&M package in

March2011. Equipments received at site recently. Erection

/commissioning will be carried out during R&M works as

scheduled in the lean hydro season of 2013-14. Expected date of

commissioning of the system is by March2014.

Khandong2X25 MW

For 50 MW Kopili Unit-III, Unit-IV & Khandong 2X25 MW units,

as the existing governing system are not compatible for RGMO

operation; The matter has been taken up with BHEL, who is theOEM for the system. On receipt of financial offer from BHEL, order

shall be processed for the system. It is expected that the system

can be commissioned by March2014.

Kopili Stg-II

1x25 MW

The existing governor of 25 MW Stage-II PH is microprocessor

based. However, for RGMO, the necessary software has to be

loaded in the system. Offer from OEM already received and under

process for placement of order. Expected date of commissioning isby March2013.

In place of

On RHEP- RGMO installed; Khandong/Kopili- Extension till March, 2014 has been

requested from CERC.

Wi t h t h e a b ov e c o r r ec t i o n s , t h e m i n u t es o f 8 2 n d O CC m eet i n g w a s co n f i r m ed .

SE (O), NERPC then requested NERLDC to give the presentation on 1) ATC/ TTC

Calculation 2) Special Protection Scheme of Pallatana evacuation 3) The grid

performance of NER during the month of February, 2013. The presentations are

enclosed at Annexure-A.


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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 FEB 2013

As per the data made available by NERLDC, the grid performance parameters for

February, 2013 are given below:

i) Average frequency during February, 2013 was 50.09 Hz as compared to 50.01

Hz in January, 2013.

ii) Minimum frequency in February, 2013 was 49.40 Hz (22.02.13 at 06:50 hrs) as

compared to 49.30 Hz Hz recorded in the previous month.

iii)

Maximum frequency was 50.71 Hz (16.02.13 at 23:59 hrs) as compared to 50.78Hz recorded in January, 2013.

iv) System frequency remained within permissible range of 49.7 Hz to 50.2 Hz for

80.00 % of the time, below 49.7 Hz for 4.89 % and above 50.2 Hz for 18.68 % of

the time as compared to 83.12 %, 5.57 % and 11.31 % respectively in the

previous month.

v) Regional peak demand in February, 2013 was 1934 MW as compared to 1943

MW in January, 2013, a decrease of 0.46 % over the previous month.

vi) Regional peak availability was 1845 MW as compared to 1815 MW in previousmonth, an increase of 1.65 % over the previous month.

vii) Energy requirement was 876.43 MUs in February, 2013 compared to 991.54

MUs in January, 2013, a decrease of 11.62 % over the previous month.

viii) Regional energy availability was 818.37 MUs compared to 924.82 MUs in the

previous month, a decrease of 11.51% over the previous month.

ix) Rise in demand met was recorded in Tripura (8.59%), Meghalaya (6.45%) & Ar.

Pradesh (3.81%) over the previous month.

x) Drop in demand met was recorded in Nagaland (8.42%), Assam (5.69%),

Manipur (5.08%) & Mizoram (4.29%) over the previous month viz. January, 2013.

xi) Over Voltage observed at Misa S/S (422kV).

xii) No over Voltages were observed at 220kV & 132 kV S/S.

xiii) No under Voltages were observed at 400 kV S/S, 220 kV S/S & 132kV S/S.


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xiv) Regional Generation & Inter-regional Exchanges during the month of

February, 2013 compared to January, 2013 are given below:

SN Parameter February, 2013 January, 2013

REGIONAL GENERATION & INTER REGIONAL EXCHANGES (in MU)

1 Total Generation in NER (Gross) 552.454 687.508

2Total Central Sector Generation

(Gross) 314.987 419.115

Total State Sector Generation (Gross) 237.467 268.393

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Inter-Regional Energy Exchanges (a) NER - ER 4.22 6.02(b) ER - NER 283.22 268.36

(c) Net Import 279.00 262.34

The Summary of Category A, B, C Messages issued by NERLDC for the constituents

of NER for the Month of January, 2013 is given as below:

State

A

(


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FOLLOW UP ACTION

C.1 Synchronization of Pallatana Module -I

During 79 th OCC meeting, AGM, NERLDC informed that OTPC had synchronized

their machine and generated around 30 MW during Durga Puja which was of great

help to NER grid during puja.

During 79 th OCC meeting, GM, OTPC had informed that to ensure capability of

plant and various equipment, auxiliaries & ancillaries associated with Block-1 /

Unit-1 of Pallatana Generating station, trial operation is required with increase of

loads in steps as per schedule and after unit stabilization run, machine needs to be

run at full / base load and the continuous run of unit for minimum period of 72

hours is required for declaration of COD. SE(Com) informed that for declaration of

COD, the running of machine continuously for 72 Hrs is not a mandatory

requirement. But as per PPA of OTPC with the constituent states of NER, each

block/unit is to operate seventy two (72) consecutive hours at or above 95% of the

contracted capacity. OTPC had informed that after running of Block-1

continuously for 72hrs. at full / base load, the machine could be run at reduced

load for fifteen (15) days. The running of Unit at full / base load is required to

demonstrate gross generation, heat rate, auxiliary consumption, and NOX level

including capability & reliability of various equipment, auxiliaries, ancillaries and

associated control and protection system.

AGM, NERLDC stated that all tests required for commissioning of Pallatana U#1

will be facilitated by NERLDC as agreed in previous OCC meetings but the

commercial issues with the stake holders i.e. NEEPCO/NHPC/Tripura have to be

settled by OTPC.

POWERGRID informed that 400 kV Silchar- Pallatana-II tripped number of times on

07/11/12 on overvoltage due to some problem at OTPC end, the same needs to be

checked.

OTPC informed that the investigation is going on and it will be rectified soon.


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NERLDC also informed that as per the previous decision in OCC meeting all

constituents had agreed for 72 hours of continuous run of Palltana U#1 at full load

(i.e. 300 MW). For evacuation of full generation of Pallatana U#1, Tripura, Assam,

NEEPCo and NHPC have to back down their generation. Therefore, if OTPC requires

continuous load more than 72 hours (3 days), all constituents should agree forsuch transaction and the commercial issues also needs to be resolved beforehand.

NERPC had given a presentation on the commercial implication of backing down of

generation by NHPC, NEEPCO, Tripura, and Mizoram due to injection of generation

by Unit-1 of Pallatana taking into account the previous load flow study on case to

case basis.

Assam stated that backing down of generation may be allowed, but frequentramping up/down of generation is not desirable as it may lead to cascading effect

resulting in a grid disturbance. Further they stated that the generation status at

Pallatana should be integrated with the SCADA system of all SLDCs.

Tripura also stated that the commercial implication should be settled beforehand.

NEEPCO also informed that for running of Unit-1 for more than 72 hours, prior

approval from their management would be required. NEEPCO requested for steadyinjection of power for the whole day to manage their gas supply. OTPC informed

that it is difficult to maintain steady injection of power to the grid during trial

operation.

OTPC informed that since all constituents are not agreeing for full load generation

for 15 days, reduced generation of 250-280MW may be allowed after continuous

run of Unit-1 for 72 hrs. at full / base load.

During discussion POWERGRID was requested to inform the committee about the

present status of 400kV Silchar Byrnihat line and the 400kV substation at

Byrnihat. Committee requested for commissioning of line and substation by the end

of November 2012. But POWERGRID informed that it is difficult to commission the

GIS substation before December 2012.


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In the 79 th OCC meeting, after detailed deliberation the committee reiterated its

earlier decision to allow continuous run of the Unit-1 for 72 hours at full load.

Further OTPC should furnish its schedule at least 48Hrs beforehand to enable all

the stake holders to carry out proper planning. However, the commercial matter

regarding running of Unit-1 beyond 72 hours at full / reduced load needs to be

discussed in commercial committee and NERPC meeting to settle the commercial

implications.

During 80 th OCC meeting, Committee requested POWERGRID to inform the house

about the status of 400kV Silchar Byrnihat line and the 400kV substation at

Byrnihat. POWERGRID informed the committee that the stringing work of 400kV

Silchar Byrnihat line is under progress and is likely to be completed by January,

2013. Regarding 400kV GIS substation at Byrnihat it was informed that Reactor oilfilteration is in progress and one transformer has also reached the site. The pre-

commissioning tests will be completed as early as possible. The commissioning of

400kV GIS cannot be completed before January, 2013 although most of the

erection commissioning activities on 220kV side will be completed by December,

2012.

GM (Plant), OTPC informed that synchronization of Unit -1 would be done again on

14.12.12 for further tests and COD and submitted the schedule to NERLDC. Thecommittee deliberated the generation schedule of OTPC Pallatana w.e.f. 14.12.12

and after detail discussion it was decided that:

i) On 14.12.12 OTPC should synchronize Unit-1 before Peak Hours (i.e. 17:00

Hrs) and the generation should be in the range of 50 to 80 MW so that it will

help NER grid during Peak hours and moreover, start-up power should be

drawn from the Grid during off-peak hours, which will help the TSECL system.

Afterwards the load may be increased gradually.

ii) On 15.12.12 OTPC should plan to generate about 300 MW (for 2 hours) during

Peak hours so that such quantum of generation can be easily accommodated.

iii) From 15.12.12 to 24.12.12 OTPC should generate around 230 to 250 MW

continuously. However, the generation needs to be rescheduled, if required,

depending on real time grid conditions and as per the advice of NERLDC.


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iv) If OTPCs generation would be found to be stable, then generation of 230 to 250

MW can be continued further till 02.01.2013 to support the grid during

Christmas and New Year eve.

v) From 03.01.2013 onwards, OTPC may plan for generation of 363 MW (full

load/base load) continuously for 72 hours in consultation with NERLDC.

During 81 st OCC meeting, the Sub-committee enquired about the status of

commissioning of Unit#2 of GBPP at Palatana from OTPC and also the status of the

ATS from POWERGRID.

OTPC informed that the commissioning schedule of Pallatana U#2 is May/June,

2013. Further, OTPC requested to facilitate for following schedule of generation.

i) Generation of 300 MW for 4-5 hours on 11.01.2013 for DLN testing

ii) Continuous Generation of 250 MW for seven (7) days for trial operation.iii) Generation of 360 MW for three (3) days to meet the requirement of COD.

POWERGRID informed that the commissioning schedule of ATS is as follow:

a) 400 kV Silchar Byrnihat Transmission line By end of January, 2013

b) 400 kV GIS Byrnihat S/S- By end of January, 2013

c) 400 kV Byrnihat Bongaigaon Transmission line By May/June, 2013.

TSECL and Assam representatives requested NERLDC not to issue ATC violation

message as States were overdrawing continuously to match the load requirement

with generation from OTPC. They also requested for some action to avoid UI drawl

at higher rate as it effects commercially.

After detailed deliberation the committee decided that:

i) On 11.01.2013 OTPC will inject 300 MW for five (5) hours during peak hours

to perform the DLN testing.

ii) Subsequently generation of OTPC will be restricted to 250 MW during peak

hours and 150 MW during off-peak hours till 400 kV Byrnihat S/S and 400

kV Silchar Byrnihat line is commissioned.

iii) However, in case of any contingency, OTPC will have to back down generation

as per advice of NERLDC.


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During the 82 nd OCC meeting, GM (Plant), OTPC informed that DLN tuning in PPM

mode has been completed for generating Unit#1 at Palatana. But the DLN tuning in

PM mode is yet to be done. For DLN tuning in PM mode, load of about 300MW

would be required and after DLN tuning, load of about 250 MW is required

continuously for further trial run of the machine.

POWERGRID was requested to intimate the status of commissioning transmissionsystem associated with evacuation of power from generating units of OTPC at

Pallatana and NTPC at Bongaigaon. POWERGRID informed that the status of

transmission system is as below:

i) 400 kV Silchar Byrnihat Transmission line By February 15, 2013

ii) 400 kV GIS Byrnihat S/S- Charged on January 5, 2013.

iii) 400 kV Byrnihat Bongaigaon Transmission line By June, 2013.

NERLDC presented the recent trippings and shut down programme of OTPC

generating unit during trail operation. The committee requested OTPC to stabilize

their machine as the records of NERLDC shows the machine is not stable and it is

tripping during trial operation and shut down is being taken now and then. Since

the NER grid may not be able to survive in case of tripping of generating unit of

such capacity (363MW) as it may lead to cascade trippings. The machine should be

stabilized before going for trial run with full generation.

After detailed deliberation the committee has decided as follows:i) The generating Unit#1 of OTPC should be stabilized as tripping of the

machine at full load may cause grid disturbance.

ii) Because of election in the state of Tripura on February 14, 2013, trail

operation of machine with full generation may be deferred till 400 kV Silchar-

Byrnihat line is ready in order to avoid interruption of power supply.

iii) The commissioning of 400 kV Silchar-Byrnihat line is expected by

January15, 2013 and trial run of OTPC machine with full generation can be

carried out after 15 th February, 2013.

D el i b er a t i o n o f t h e Co m m i t t e e

POWERGRID informed that the status of transmission system is as below:

i) 400 kV Silchar Byrnihat Transmission line Charged on March 26, 2013

ii) 400 kV GIS Byrnihat S/S- Charged on January 5, 2013.

iii) 400 kV Byrnihat Bongaigaon Transmission line By June, 2013.


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GM (Plant), OTPC informed that due technical problem with Unit # 1, the

generation from the plant has been stopped. The interior shields of Steam Re-

heating Boiler of Unit#1 are defective causing melting down of the metals and the

same needs replacement. Attempt will be made to divert the shields designed for

Unit-II to be used for Unit-I so that Unit-I can resume generation by 5th of May

2013.

The committee also informed that since six month period from the commencement

of injection of power to the grid will be over in April 2013, injection of firm power

into the grid will not be possible by OTPC after April as per CERC norm. OTPC was

requested to take up the matter with CERC so that power can be injected into the

grid when the machine is ready for generation in May 2013.

T h e Su b -c o m m i t t ee n o t e d a s a b o v e.

C.2 Independent third party audit of protection system and self-certification inrespect of operationalisation of Under Frequency Relay (UFR) and df/dtrelay

The Chairperson, CEA vide his D.O letter No. 7/AI/GD/GM/2012/397-407,

addressed to Honble Chairperson, NERPC had requested for completion of

independent third party audit of protection system and to ensure operationalisation

of Under Frequency Relay (UFR) and df/dt relay based automatic load shedding

within one month. In response to above letter NERPC vide letter No.NERPC/OP/OCC/2012/5687-702 had circulated extract of CEA & CERC

regulation and some formats, with typical example (which can be downloaded from

NERPC website), to help in collecting various information. No. of groups need to be

formed to carry out the protection audit. The action plan needs to be discussed so

that the work can be completed as early as possible.

However, the self-certification (by STUs / CTU) in respect of operationalisation of

Under Frequency Relay (UFR) and df/dt relay based automatic load shedding mayplease be submitted in the prescribed format to NERPC and CEA at the earliest.

During 79 th OCC meeting, SE (Comml), NERPC informed that as recommended by

Enquiry Committee, the third party independent audit for the Protection systems in

NER is to be completed as early as possible and presently Ministry of Power and

CEA are also monitoring the progress in various regions it very closely. Therefore,

for the benefit of the NER, the upgradation of protection system is very much


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required for smooth and reliable operation of grid and action should be initiated at

the earliest. Further, he informed that third party independent audit of Protection

systems for Northern region has already been completed by PGCIL in association

with CPRI and other regions have also started their action plan. He informed that in

NER there are about 135 Nos. of substations/ generating stations of 132kV and

above voltage class and also proposed to carryout protection audit for all these

substations / generating stations as 132kV system forms the backbone of NER

unlike other regions. Since arrangement of funds is the major constraint in NE

region, small groups /teams have to be formed taking representation from NER

constituents. The committee decided to form teams comprising of four (4) members

from different state utilities/owner, PGCIL/NEEPCO/NHPC and NERPC/NERLDC.

NERPC will co-ordinate the audit and prepare the further course of action in

consultation with NERLDC and POWERGRID. The nominated member of

NERPC/NERLDC will be the co-ordinator of each group.

Further, NERPC, in consultation with POWERGRID and NERLDC, had prepared the

detailed plan for carrying out the audit of protection system of all 132 kV and above

voltage class substations/generating stations in NER. NERPC vide letter dated 26 th

November, 2012 and 30 th November, 2012 had requested PGCIL and other

constituents to provide logistic support inform of road transport and stay at various

places in NER.

During 80 th OCC meeting, Member Secretary I/C, NERPC informed that ED,

POWERGRID has agreed to provide required support for carrying out the audit of

protection system. He also informed that the protection audit for Tripura is likely to

be completed before Christmas and from second week of January, 2013, other

teams will proceed for the audit and entire audit is likely to be completed by

February, 2013. Further, he requested all the constituents to nominate their

representatives for the audit.

Assam submitted their nominations for audit team. Other constituents agreed tonominate their persons for audit team. After detail deliberation all the constituents

agreed to the proposed dates and to extend their supports to complete the audit in

time bound manner.

During 81 st OCC meeting, MS I/C informed that Protection Audit of most of the

substations/generating stations in the state of Tripura had been completed. He


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requested all the constituents to extend their supports to complete the audit by

February 2013 as per Schedule.

The Committee reviewed the status of the Protection Audit and requested each

Audit team to prepare a report on findings / observations pertaining to various

substations / generating stations audited by them.

MS I/C, NERPC informed that as per the planning out of nine (9) routes identified

the audit of protection system pertaining to route no. 1, 4, 6, 7 and 8 have been

completed and presently audit in respect of route no. 2 and 5 is going on which will

be completed by 11 th February, 2013. These routes cover most of the

400/220/132kV Sub-Stations and Generating stations in Ar. Pradesh, Assam,

Manipur, Mizoram, Nagaland and Tripura. The audit of rest of two (2) routes (route

no. 3 and 9) will commence from 11 th February, 2013. Further, he stated that as on

date protection audit in respect of about 100 substations / generating stations hasbeen completed and rest of the work is likely to be completed by February, 2013.

After completion of protection audit, the deficiencies in the NER system will be

highlighted and discussed in OCC/PCC meetings. The course of action and time

frame of implementation of recommendations of protection audit will be planned

accordingly. The report on Protection audit along with recommendations will be

submitted by March, 2013.


MS I/C, NERPC briefed the members about the deficiencies observed in some of the

audited sub-stations and highlighted the inadequacy of diagnostic tools in most of

the stations. As reported by auditing team, details of relay setting are also not

available with operating personnel of some of the substations which should have

been available with them as the core of protection lies in the relay settings. The

formats of reports were also highlighted to the members for perusal.

GM, NERLDC suggested that shortage of man-power may also be highlighted in the

reports as round the clock manning of sub-stations is very important for effective

and efficient management of the systems.



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

During 79 th OCC, Manipur had informed that the UFRs have been installed on 33

kV Yurembum-Limukhong radial feeder as advised by the committee. In the

process installation of all UFRs in the NER has been completed as per earlier

decision of the committee. Further all constituents (STUs and CTUs) were

requested to furnish the relevant information in the format prescribed by CEA. It

was also discussed that the requirement of UFR and df/dt relays need to be

reviewed based on the recommendation of the enquiry Committee constituted by

the Ministry of Power headed by Chairperson CEA.

During 80 th OCC meeting, MS (I/C) informed that after the grid disturbance, the

Ministry of Power and CEA are closely monitoring the progress in implementation

of recommendations of Enquiry Committee. CEA is also asking the operation

details of UFRs every now and then. Therefore, all constituents are requested to

submit the requisite data at the earliest. Constituents, who have not submitted the

required information, have agreed to submit the same at the earliest. Further, he

informed that the frequency band has been tightened further by CERC to 49.7 to

50.2, therefore the frequency settings and load relief is further required to be

reviewed.

During the 81 st OCC meeting, NERLDC informed that the Committee for Security

of grid constituted by Ministry of Power has revised the quantum of under

frequency based load shedding at various frequency bands. Therefore, the under

frequency based load shedding in respect of NER needs to be reviewed.

The Committee requested NERPC to finalize the UFR based load shedding in

consultation with NERLDC. However, for finalization of UFR based load shedding,

further detailed discussion would be required.

During the 82 nd OCC meeting, SE (O), NERPC enquired from constituents whether

the UFRs installed in the region have operated during the recent grid disturbances

occurred on 14.12.2012 & 20.01.2013. He requested all the constituents to

furnish the details of UFR operation. All constituents agreed.


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As per clause no. 5.2(n) of IEGC, utilities are to submit UFR operation report on

monthly basis to RPC. All constituent states are requested to inform the committee

about the operation of UFR since its commissioning, particularly during grid

disturbances, which is being monitored strictly by CEA/MoP after the grid

disturbances on 30th & 31st July, 2012. The UFR operation detail may please be

furnished to RLDC and NERPC as per format circulated.

All constituents agreed to submit the data in the prescribed format.

The Committee also suggested that if UFR operation can be linked to annunciation

on control panel, then operation of UFR can be easily recorded.


After deliberation, it was agreed that whenever sub-stations are upgraded or

renovated, possibility of installing automated control panels should be explored so

that reports on operation of UFR and other technical details may be recorded and

collected efficiently at regional level.

S.E (O) requested all the Constituents to submit the report of UFR operation every

month as per the format circulated by NERPC and if no operation has taken place

then a NIL report maybe submitted so that the same can be circulated with the

minutes of the meeting.

The constituents requested to discuss the issue in detail during the forthcoming

PCC Meeting.

T h e S u b -c o m m i t t ee n o t e d a s a b o ve.

C.4 Lines under long outages

During 80 th OCC meeting, the status of lines which are under long outages as given

below were reiterated

(a) 220kV BTPS Agia (one ckt) since Novemeber, 1997

(b) 132kV Mariani Mokokchung since April, 2008.

(c) 39km of 132kV Rengpang Jirbam since October, 2002

(d) 132 kV Dimapur-Dimapur-II


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Assam representatives informed about 220 kV BTPS-Agia- II that it is under

stringing stage and it was delayed as the tender was terminated because

contractor cannot complete the said job in time. The new tendering is in progress

and it will be completed at the earliest. Regarding Mariani-Mokokchung line the

Assam side is ready; the Nagaland side is required to be checked.

Regarding 132 kV Rengpang-Jiribam line the Manipur representatives informed

that the work is in progress and the same will be completed by January, 2013.

Further, NERLDC informed that the Dimapur-Dimapur-II is also under long

outage.

The committee requested NERPC to take up the matter with the concerned State

for early restoration of these lines for better grid operation.

During the 81 st OCC meeting, Assam informed that 220 kV BTPS-Agia will be

restored by September, 2013.

Manipur informed that commissioning of 132 kV Rengpang-Jiribam line will be

completed by January, 2013.

The Committee requested NERPC to take up the matter with Nagaland.

In response to NERPCs letter dated 14-12-2012, CE, Nagaland, vide his letterdated 21 st January 2013, have informed that the portion of 132kV Mokokchung

Mariani line (under the jurisdiction of Nagaland) has been kept charged at 33kV

and can be charged at 132kV at any point of time provided portion of line in Assam

is ready. With regard to 132kV Dimapur (PG) Dimapur (N), in a joint meeting on

16-01-13, it has been decided that POWERGRID, Dimapur will discuss the matter

regarding operation procedure with DoP, Nagaland.

The status as reviewed in the meeting are as under:

(a) 220kV BTPS Agia (one ckt) Assam informed that the tender has been opened

and same is under technical evaluation.

(b) 132kV Mariani Mokokchung Assam and Nagaland to co-ordinate and bring

back the line by February, 2013.

(c) 39km of 132kV Rengpang Jirbam Manipur informed that stringing for 5 km

section is left out and the same is likely to be completed by February 2013.


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(d) 132 kV Dimapur-Dimapur-II POWERGRID to co-ordinate with Nagaland and

discuss operation issues before election (i.e. 23.02.2013)


(a) 220kV BTPS Agia (one ckt) Tender has already been opened and order islikely to be placed by April, 2013

(b) 132kV Mariani Mokokchung CGM (SLDC), AEGCL informed that the line

was charged but tripped immediately after charging due to faults in some

portion of the lines under Nagaland. He requested NERPC to pursue with

Nagaland officials for joint inspection.

(c) 39km of 132kV Rengpang Jiribam Manipur informed that stringing is

almost complete and the same is likely to be completed by March 2013.

(d) 132 kV Dimapur - Dimapur - II POWERGRID informed that Nagaland hasagreed to the proposals made by them and the issue will be resolved soon.


C.5 SPS scheme for Pallatana

It was observed from load flow studies carried out by NERLDC that tripping of

Pallatana unit during peak hours would cause loading of Kopili ICT (160 MVA). To

save the situation shedding of around 100 MW of load would be required in the

132 KV pocket through SPS.

During 76 th OCC meeting, DGM, NERLDC had informed that a special protection

scheme is required to be planned for shedding the above load. The committee

advised NERPC Secretariat to design the SPS in consultation with NERLDC,

Assam, Meghalaya, Tripura, NEEPCO, NHPC and OTPC.

POWERGRID representatives had informed that not only SPS but protectionschemes are also required to be reviewed before commissioning of Pallatana GBPP.

From the load flow study it was observed that in certain lines there will be reverse

flow of power due to tripping of Pallatana.

The committee had requested POWERGRID to study the protection schemes and

prepare a report. The same will be discussed in the next OCC meeting.


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During 77 th OCC meeting, DGM, NERLDC stated that in case of tripping of

Pallatana unit, around 120 MW load shedding through SPS would be required in

Mizoram, Tripura and South Assam (each 40 MW) and some load shedding would

be required in Meghalaya. POWERGRID informed that the implementation of SPS

for tripping of far off lines/loads will be difficult as there will be co-ordination

problem because of non-availability of communication links and NERLDC should

find some other nearby lines or SPS can be linked with Kopili ICT. NERLDC

informed that they have identified the list of radial lines in NER system for

disconnecting during emergency conditions to save the grid. They pointed out that

the SPS can be implemented on those lines which are available in 132 kV Pocket.

All the constituents agreed for implementation of SPS on these lines and also for

emergency disconnection of listed lines in case of necessity.

The committee felt that the SPS scheme is required to be in place at least before

the synchronization of Pallatana unit. After detailed deliberation committee

requested NERLDC to prepare the SPS scheme of Pallatana in consultation with

NERPC and POWERGRID.

During 79 th OCC meeting, NERLDC informed that lines have been identified in

NER system for disconnection during emergency conditions to save the grid. SPS

can be planned accordingly. The committee requested NERLDC to give the list of

lines associated with tripping of Unit-1 at Pallatana and POWERGRID was

requested to plan the implementation of the SPS scheme.

During 80 th OCC meeting, the committee felt that NERPC, NERLDC and

POWERGRID may discuss the matter and plan accordingly for implementation of

SPS scheme.

NERLDC gave a presentation on grid security for tripping of i) 400 kV Silchar-

Killing (Byrnihat) line and ii) Palatana Units. The handout of the slides is enclosed

at Annexure- C.5 .

During 82nd OCC meeting NERLDC requested for creation of Power system study

group as per recommendation of enquiry committee for Grid disturbance. The sub-

committee had agreed for the same. The matter was also brought to the notice of

members of TCC and the TCC has also agreed for creation of Power system study

group in the region taking representation from various constituent states,


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POWERGRID, NERLDC, NTPC, NEEPCO, NHPC, OTPC and IIT Guwahati. The

studies relating to islanding scheme, SPS and any other studies required from time

to time can be carried out by the group. The group will not only help for studies on

regional basic but will of great help to each state for their planning studies. All

members were requested for nominations to the group.


The System Protection Scheme (SPS) associated with tripping of generating unit of

OTPC at Pallatana or tripping of 400 kV Silchar-Byrnihat line, prepared by

NERLDC, was deliberated during the presentation given by GM, NERLDC. GM,

NERLDC emphasized that implementation of the SPS is essential to maintain grid

security under above contingency conditions. The tripping of above generating unit

or 400kV line may cause grid disturbance which may even lead to grid collapse.

The scheme involves immediate tripping of few identified lines at 132kV level

within two hops from the Silchar bus. It was agreed that the scheme will require

carrier inter-tripping provision for effective load shedding.

DGM, NERTS informed that the existing PLCC channels are fully utilized and there

is no spare channel for such carrier inter-tripping and new channels need to be

established additionally.

It was agreed that NERTS would examine the scheme in details and would initiate

necessary action for successful implementation of the proposed protection scheme

at the earliest possible time and the status of implementation plan would be

reviewed in next OCC meeting. In 82nd OCC meeting and special TCC meeting, it

was decided to create Power system study group in the region taking

representation from various constituents including IIT (Guwahati) and nomination

was also requested. Regarding nomination for system study group, the following

points are noted:

Ar. Pradesh - Nomination will be intimated at the earliest.

Assam Nomination will be intimated in coming PCC meeting.

Manipur - Nomination will be intimated within a week.

Meghalaya - Nomination already furnished

Tripura - Nomination will be intimated within a week.


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NEEPCO - Nomination will be intimated soon.

NERLDC Nomination will be intimated soon

NERTS Nomination already given

OTPC Nomination will be intimated soon

Mizoram & Nagaland representative were not present, NERPC will take up the

matter with them.

IIT, Guwahaty nomination will be taken up by NERPC Secretariat.


C.6 Implementation of islanding scheme in NER

For survival of different parts/pockets (with identified generation along with some

load) of NER grid in the event of grid disturbance, islanding schemes are required

to be planned properly & implemented.

DGM, NERLDC stated that some islanding schemes need to be planned so that the

islands survive during any grid disturbance so that start-up power can be

extended to other generating stations.

During 77 th OCC meeting, the islanding scheme for NER was discussed in detail

for separating of NER system from NEW grid and forming of islands in NER. Two

proposals for islanding scheme were discussed.

In both proposals, first step is isolation of NER from NEW Grid at a particular

frequency by tripping of 400kV D/C line and 220kV D/C line connecting ER and

NER. In one case it has been proposed for formation of two Sustainable Small

System (SSS) and then Unit islanding and ultimately Safe shutdown of Generating

units when frequency falls to different levels. The frequency level at which actions

are to be initiated is to be finalized after discussion.

The Committee requested all the constituents to study the islanding schemes and

communicate their comments/suggestions at the earliest so that the islanding

scheme for NER can be finalized.

Further, DGM, NERLDC informed that the list of radial lines in NER system, which

can be tripped during emergency to save the grid, have been identified. During


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emergency there may not be time to co-ordinate with SLDC (like written message

etc.) before taking such action. However, formal communication shall be made by

NERLDC afterwards.

During 79 th OCC meeting, the committee felt that further study is required before

finalizing the islanding scheme for NER. The committee requested all the NER

constituents to study their systems and give suggestions/comments, if any before

finalization of the same. All constituents agreed.

During 80 th OCC meeting, MS I/C stated that the frequency level at which actions

are to be initiated, location of UFR & df/dt relays and communication link required

etc. needs to be studied for implementation of islanding scheme. The committee

suggested that NERPC, NERLDC and POWERGRID may discuss and plan

accordingly for implementation.

MS (I/C) informed that as per the minutes of the second meeting of Task Force for

Power System Analysis Under Contingencies under the Chairmanship of ex-

Member (PS), CEA, the number of small islands may not be the optimum solution.

Further, he informed that as NER grid is a small grid, so the Task force may

consider NER as a single island. Therefore, few numbers of island scheme for NER

grid should be considered to avoid operational difficulty.

SE(O), NERPC suggested that NER system may be divided into two islands,

however, further studies and discussion would be required for finalizing the

scheme.

GM, NERLDC also stated that further studies are required for planning and

implementation of the scheme.

The committee requested NERLDC and NERPC to study the system and prepare

final islanding scheme requiring minimum number of line opening and keeping in

view the system operation as well as implementation aspects.


The study group mentioned in item C.6 above will look into the matter and the

same will be reviewed in OCC/PCC meetings.



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C.7 Loadability Enhancement of 132KV Transmission lines:

NERLDC has requested POWERGRID, vide their letter No.NERLDC/GM/547 dtd

14.11.2012 for enhancement of loading capacity of the following lines:

a) 132KV S/c Badarpur-Khliehriat Line

b) 132KV S/c Loktak-Jiribam-II Line

c) 132KV S/c Dimapur-Imphal Line

d) 132KV S/c Imphal-Loktak-II Line

NERLDC has stated that enhancement of loading capacity of the above lines is

required for higher load dispatch, particularly in the context of evacuation of power

from Pallatana GBPP.

Accordingly, POWERGRID has already taken the following actions for increased

loadability:

Upgradation of existing CTs

Upgradation of the terminal CTs of 132KV S/C Loktak-Jiribam_II line, 132KV S/c

Dimapur-Imphal line is being taken up by POWERGRID for which the required

number of CTs of higher capacity (600/1) had already been ordered by

POWERGRID & subsequently dispatched from the manufacturer premises in the

month of July-12. However, 10Nos. CTs were damaged during transit. The matter

has been taken up with the concerned manufacturer for replenishment of the

damaged CTs. The new CTs expected to arrive at site by January13.

Installation of the same shall be carried out on arrival of the new CTs. As for 132KV

Badarpur-Khliehriat line, the terminal CTs installed are of 600/1 capacity.

During 80 th OCC meeting, NERLDC requested to include following lines for

enhancement of loading capacity:

i) 132 kV Khandong- Khlerehiet I

ii) 132 kV Khandong - Haflong

The committee requested POWERGRID to complete the CT replacement of the

above lines at the earliest to increase the loadability of these lines.


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During 81 st OCC meeting POWERGRID informed that the Khandong end CTs are

having ratio of 300/1 which belongs to NEEPCO. The committee requested

NEEPCO to replace the CTs with higher ratio depending on system requirement at

the earliest.

The committee had requested NERPC Secretariat to write to NEEPCO for

replacement of above CTs at the earliest. NERPC Secretariat, vide letter No.

NERPC/OP/OCC/2013/2877-78 dated 13-02-2013 had requested NEEPCO to

take up the matter.

NEEPCO informed the house that tenders are yet to be called for procurement ofCTs .

Fixing of Additional Jumpers:

Fixing of additional jumpers at Tension Locations of 132KV Dimapur-Imphal line

has been completed while that for 132KV Jiribam-Loktak_II line is planned for

execution in the month of January-13.

In addition to the above, additional jumpering is now planned to be taken up for

132KV Loktak-Imphal-II & Badarpur-Khliehriat lines in line with NERLDCs

observation.

The required Special Connectors/Clamps for the purpose are under procurement by

POWERGRID. A tentative schedule for execution of Additional Jumpering Works in

the subject lines is appended below:

Sl.No.

Name of Line No. of TensionLocations for

Additional Jumpering

Proposed schedule

1 132KV Loktak-Imphal- II

38 Loc. 10 th February13 to20 th Feb13

2 132KV Badarpur-Khliehriat

176 Loc. 25 th Feb13 to 10 th Mar13

POWERGRID shall accordingly propose for the required daytime shutdown of the

respective lines in the preceding OCC Meetings

Constituents agreed to support POWERGRID for carrying out the modification

required for the lines. The committee requested POWERGRID to plan for additional

jumpering.


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POWERGRID intimated the status as below:

The fixing of additional jumpers in 132 KV Loktak Jiribam II line has been

completed on 01.03.2013. Also fixing of additional jumpers in 132 KV Badarpur

Khliehriat line & 132 KV Loktak Imphal II line the order for special connectors

has already been placed by them and the same is likely to be delivered at site by

20.03.2013. Accordingly, the work is planned to be started w.e.f. 25.03.2013 in

132 KV Badarpur Khliehriat line followed by 132 KV Loktak Imphal II line.


C.8 LGBR for 2013 -2014:

During the 82nd OCC meeting, the issue of LGBR for 2013 -14 for NE Region has

been discussed in detailed and all the constituents have been requested to submit

the data for preparation of LGBR at the earliest as per the proforma circulated.

The formats have also been made available in the website of NERPC

(www.nerpc.nic.in) which covers the outage planning for Generating units as well

as important transmission elements in state and central sector.

All utilities had agreed to submit the data by February, 2013.


S.E (O), informed that till date no constituents have submitted the above data

except TSECL, NEEPCO & Me.ECL (however, Me.ECL has not furnished the

maintenance schedule of its generating stations & transmission lines).

Constituents are requested to submit the above data in the format furnished by

NERPC at the earliest.


C.9 Grid Security Expert System (GSES):

POWERGRID has planned an automated defense plan for all five regions named as


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Grid Security Expert System (GSES). The Region wise estimated cost based on the

feeders identified by POSOCO including IDC shall be as follows:

S.N Subject NR SR WR ER NER All India

1. Estimated DPRcost of GSES(in Rs. Crores)

82.59 42.13 124.85 55.42 49.47 354.46

2. Number ofFeeders 1064 763 1502 503 410 4242

3. Estimated DPRcost of OPGWbasedcommunication

system (in Rs.Crores)

141.61 368.37 174.24 83.18 80.42 847.82

4. Length ofOPGW 4967 14706 6111 2868 2688 31340

TotalEstimated cost(in Rs. Crores)

224.20 410.50 299.09 138.60 129.89 1202.30

The GSES was discussed in detail in last Special TCC held at Shillong on 9th

February, 2013. After detailed deliberation the following decisions of the TCC was

conveyed to CERC.

1. All constituents agreed in principle to the technical requirement of the GSES

scheme for NER grid.

2. The basic infrastructure at most of Sub-station like circuit breakers, protection

relays, etc. are not adequate for implementation of the scheme.

3. There are no full fledged SLDCs in Ar. Pradesh, Manipur, Mizoram andNagaland.

4. Funding is major concern as NER states are financially weak.

5. The quantum of UFR based load shedding needs to be relooked for NER States.

6. More deliberation on technical and commercial issues is required before

formulation/implementation of the scheme.


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All constituents had agreed in principle to the technical requirement of the GSES

scheme for NER grid, but more deliberation on technical and commercial

implication was required before formulation / implementation of the scheme.

I t w a s a g r ee d t h a t D PR p r e p a r ed b y POW E R GR I D f o r G SE S a n d o t h e r r el a t e d

d e t a i l s w i l l b e s en t t o co n st i t u e n t s t a t es f o r s cr u t i n y a n d t h e m a t t e r w i l l b e

d e l i b er a t e d f u r t h er i n O CC/ CC m eet i n g .

C.10 Assessment of Total Transfer Capability (TTC), Transmission ReliabilityMargin (TRM) and Availability Transfer Capability (ATC) by SLDC onrespective Inter-state transmission corridor:

As per Clause No. 4.1 of Detailed Procedure for Relieving Congestion in Real Time

Operation, SLDC shall assess TTC, TRM and ATC on its inter-state transmission

corridor considering a mesh intra-state corridor for import or export of power withthe Inter-state Transmission system (ISTS).

SLDCs of NER are requested to assess the above on monthly basis, 5 months in

advance (eg: TTC/TRM/ATC for the month of November to be calculated by 15th of

July), for further assessment of TTC, ATC and TRM of NER ER corridor by

NERLDC and for assessment of TTC / ATC for a group of control areas, individual

control areas with the region and state-control-area to state-control-area by

NERLDC, if required.

Power Utilities are requested to send the results of calculations along with

assumptions and *.sav (PSS/E saved case format) files to NERLDC by 15th of the

month.

During the 81st OCC meeting, the committee requested SLDCs to take initiatives

for assessment of TTC, TRM, ATC for their inter-state transmission system.

NERLDC gave a presentation on the congestion of ER-NER corridor.

During 82nd OCC meeting, Assam Representatives stated that the criteria and

methodology of calculation of TTC/ATC with typical example may be made

available to the constituents so that they will be aware of the TTC calculations and

they can calculate TTC/ATC for their own system / inter-regional/intra-regional

transmission line.


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NERLDC agreed to provide the details of criteria and methodology of calculations of

ATC/TTC.


During the meeting, NERLDC had also made presentation on this issue to

highlight about the technical constraint. All the constituents requested NERLDC to

enhance the ATC/TTC so that acute shortage of power in the region can be relieved

during the lean hydro period, since generation from Pallatana GBPP is not

expected before May, 2013.

GM, NERLDC informed that due to limitation in 400 KV Farakka Malda D/C line

and (N-1) criteria, the import of power from ER is being restricted by NLDC.

S.E (O), NERPC suggested that matter should be discussed with ERPC and CEA

All the constituents agreed to the proposal.

T h e Co m m i t t e e n o t ed a s a b o ve .


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D. N E W I T E M S

D.1 Proforma for Operational Statistics

The operational Statistics as given below was not furnished in the meeting.

(i) Schedule Vs Actual Generation.

(ii) Peak Demand: Schedule Vs Actual.

(iii) Integrated Operation of the system.

(iv) Details of DC, schedules and injections from Central sector stations, drawalschedules and entitlements of constituents.

(v) Details of major reservoirs in NER.

T h e o p er a t i o n a l s t a t i c s w er e s h o w n i n t h e p r es en t a t i o n b y NE RL D C.


D.2 State-wise anticipated peak demand/requirement, shortage for March- July,2013.

T h e su b -Co m m i t t ee r e vi e w ed & f i n a l i z ed t h e a n t i c i p a t ed p e a k

d e m a n d / en e r g y r e qu i r em en t / Av a i l a b i l i t y (w i t h o u t Pa l l a t a n a g e n er a t i o n ) f o r

t h e m o n t h s of M a r c h t o J u l y, 2 0 1 3 .

A. Peak Demand

S.No. State

Peak

Demand

(MW)

Mar 13

Peak

Demand

(MW)

Apr 13

Peak

Demand

(MW)

May 13

Peak

Demand

(MW)

Jun 13

Peak

Demand

(MW)

Jul 13

1 Ar. Pradesh 105 105 110 110 130

2 Assam 1210 1230 1250 1250 13003 Manipur 105 100 110 110 130

4 Meghalaya 280 280 290 280 280

5 Mizoram 75 70 75 70 90

6 Nagaland 115 110 120 110 120

7 Tripura 230 230 240 230 250

Region 2120 2125 2195 2160 2300


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B. Peak Availability

T h e Co m m i t t e e n o t ed a s a b o v e.

D.3 Ensuring FGMO/RGMO, AVR & PSS tuning for operation of units

In line with IEGC & other regulations the following aspects may be ensured while

operation of generating units:

i. Operation of generators under Free Governor Mode of Operation (FGMO) or

Restricted Governor Mode of Operation (RGMO).

ii. Operation of Generating Units within capability limits as per Capability Curves.

iii. Proper settings of Automatic Voltage Regulator (AVR) and

iv. Proper tuning of Power System Stabilizers.

The issue has gained significant importance in the aftermath of twin grid

disturbances on 30 th & 31 st July, 2012. All concerned are requested to please

attach maximum priority on this aspect and do the needful at the earliest. In thisregard directions of Honble CERC against Petition nos. 191/2011(Suo-motu) & 47-

52/MP/2012 may please be referred.

During the 81 st OCC meeting, the subcommittee had requested all generating

companies and constituent states of the region to furnish status of implementation

of RGMO.

S.No. State

Peak

Availability

(MW)

Mar 13

Peak

Availability

(MW)

Apr 13

Peak

Availability

(MW)

May 13

Peak

Availability

(MW)

Jun 13

Peak

Availability

(MW)

Jul 13

1 Ar. Pradesh 75 70 65 65 120

2 Assam 920 900 850 825 1000

3 Manipur 75 70 70 70 120

4 Meghalaya 180 175 170 165 250

5 Mizoram 55 50 45 45 75

6 Nagaland 75 75 75 65 90

7 Tripura 145 140 130 120 185

Region 1525 1480 1405 1355 1840


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The status of implementation of FGMO/RGMO & PSS is as given below:

Assam: Karbi Langpi HEP- The machines are very old (Manufactured in 1983) and

there is no provision of FGMO and it is not possible to implement RGMO.

Me.ECL: Umiam Stage-III- Extension has been requested from CERC for putting

FGMO.

NHPC: Loktak- Machines are operating with FGMO and sincere effort is being made

to implement RGMO by October, 2013.

NEEPCO informed that PSS tuning has not yet been done for Unit#-III of RHEP and

same is likely to be completed by 2014.

OTPC also informed that the Generating units are with PSS.

Meghalaya informed that for Umiam Stage III PSS has not been tested. The samewould be cheeked and intimated accordingly

T h e Co m m i t t e e n o t ed a s a b o v e.

D.4 Generation Planning (ongoing and planned outages)

The daily availability for hydro stations was reviewed in the meeting as per the

present water level of different reservoir which is as given below:

Khandong 0.1476 MU

Kopilli 0.6550 MU

Kopili- II- 0.3150 MU

Ranganadi - (subject to inflow)

Doyang 0.0540 MU

Loktak - 0.3150 MU

The shutdown proposal of NEEPCO/NHPC as approved by the committee is

enclosed at Annexure D.4 .

The acute shortage of power in the region, during this lean hydro period, is

compounded due to non-availability of generation from GBPP of OTPC. Expecting

the availability of generation from OTPC plant after May 2013 and taking into

consideration the acute shortage of power in the region during this lean hydro

period,


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Member Secretary I/C suggested to utilize the available water in the reservoir of

Kolipli HEP so as to provide some relief to constituent states during the peak hours.

All constituents supported the suggestion of Member Secretary I/C and NERLDC

was requested to take necessary action accordingly.


D.5 Outage Planning Transmission elements

After detail discussion the sub-committee approved the shutdown proposal for

March/April, 2013 as given in Annexure D.5.

SE (O), NERPC requested all the constituents to submit the Shutdown proposals

by end of the preceding month so that it can be planned in better way for smooth

grid operation and last minute change in shutdowns programme can be avoided.

All the constituents agreed to intimate the list of shutdowns by the end of the

current month before the next OCC meeting.


D.6

Estimated Transmission Availability Certificate (TAC) for the month ofFebruary, 2013.

The Estimated Transmission/System Availability for the month of February, 2013

furnished by PGCIL is 99.9492% as per details at Annexure D.6 . NER

constituents were requested to give their comments and observations, if any, by

25th March, 2013 so that Final TAC for the month of February, 2013 can be

issued.

T h e su b -Co m m i t t ee n o t ed a s a b o ve.

D.7 Major grid disturbances in the previous month (February, 2013 )

As intimated by NERLDC, there was no major grid disturbance during the month

of February, 2013.

T h e su b -Co m m i t t ee n o t e d a s a b o v e.


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D.8 Mock Black start exercise of ISGS stations as well as state sector generatingstations of NER:

In line with the stipulations of IEGC clause 5.8(b) mock black start exercise of ISGS

stations are being carried out every year. The exercise for RHEP & DHEP will be

carried out in the last week of February, 2013. States, who are having owngeneration are also requested to carry out similar exercise.

During the 81 st OCC meeting, the subcommittee had requested all generating

companies (state & central sector) to provide details of the Mock Black start

exercise of generating station (if carried out so far).

NEEPCO agreed to carry out the exercise as decided by NERLDC.

OTPC informed that they dont have adequate capacity of DG set to Black Start

their machine.


The issue was deliberated and GM (O&M) NHPC stated that Loktak black started

last year supplying power to Manipur for 24 hours. He further stated that in order

to carry out such mock black start, proper co-ordination is required from both

NERLDC and beneficiary states as such test is vital for security of the grid.

Sr. Manager, NEEPCO informed that mock black start was done for Doyang HEP

and the generating station was supplying power to Nagaland but hunting of

machine started while loading the machine. He requested NERLDC to check the

load increment so that proper loading of machine is achieved to prevent tripping.

T h e su b -Co m m i t t ee n o t e d a s a b o v e.

D.9 Empowering of SLDC:

It has been observed in many occasions that Shift-In-Charges available in control

rooms of some SLDCs are not able to take decision in respect of curtailment of

overdrawal, without the consent of superiors, despite of several requests from

NERLDC. This practice should be avoided by empowering the Shift-In-Charges to

take decisions on their own considering the grid condition.


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D.14 Power flow from 400/220KV Misa S/S:

Me.ECL informed that as per information available with their office the 400KV

Killing Silchar lines were energized on three occasions i.e., on the 25th February

(at 22:10Hrs), 26th February (at 21:11 Hrs) and 3rd March (at 21:26Hrs) 2013

respectively. During such occasions it is observed that there was flow of power from

the 400/220 kV MISA substation to the corresponding substation at Silchar via

Me.ECLs 220Kv MISA- Killing lines.

In view of the above, the matter on the Status of the 220 kV MISA- Killing lines with

regard to such Inter-State flow of power may please be discussed.

T h e i s su e w a s d e l i b er a t ed a n d m e m b er s a g r eed t h a t 2 2 0 k V MI S A - K i l l i n gL i n e m a y b e i n c l u d e d i n t h e l i s t o f d eem e d I S T S L i n e s i d en t i f i e d b y R PC.

H o w e ver , f o r r ec o ver y o f t a r i f f t h r o u g h Po C m e ch a n i s m , Yea r l y Tr a n s m i s s i o n

Ch a r g es f i x e d by c on c er n e d R eg u l a t o r y Co m m i s s i o n sh o u l d b e a va i l a b l e a n d

sy s t em st u d i e s n eed t o be c a r r i e d o u t t o p r o v e t h a t t h e l i n e ca r r i es m o r e t h a n

5 0 % of i n t er -s t a t e p o w e r. I t w a s a l s o n o t ed t h a t n o sy s t em s t u d i e s h a v e b ee n

d o n e f o r t h e d eem ed I S T S L i n e s i d e n t i f i e d b y R PC. T h e p r o p o sa l o f M e .E CL

w i l l b e p u t u p t o T C C/ R PC f o r a p p r o va l .

D.15 High tripping rate & Long Duration Outage of dedicated 11 KV Feeder forAuxiliary Power Supply to 132KV Badarpur Substation:

The 11 KV HT dedicated feeder emanating from Panchgram Lower Substation

(AEGCL) & connected to 132KV POWERGRID Badarpur Substation was constructed

by ASEB (as a deposit work) for catering to the Auxiliary power/station load

requirement of 132KV Badarpur Substation.

However, service of the said feeder has been found to be considerably unreliable.

On an average, the feeder has been found to trip 10-15 times a day with cumulative

outage hours up to 5 hrs per day. The matter has been taken up & repeatedly

pursued with ASEB (CAEDCL) on a number of occasions but there has been no

improvement in reliability of the feeder.


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The 132KV Badarpur Substation is a vital node for catering to the power

requirement of the 132KV pocket & is connected to major substations viz. 400KV

Silchar Substation & 132KV Panchgram Substation(AEGCL) in addition to 3 other

key substations. Further, the station is playing a significant role for evacuation of

power from Pallatana GBPP to the rest of the 132KV pocket. Hence uninterrupted

auxiliary power supply to the station is of utmost requirement for maintaining a

healthy Protection & Communication System at the station.

The issue has been discussed in 80th & 81st OCC meeting, whereby it was

informed by Assam that there are some temporary tappings from the existing 11KV

dedicated feeder connected to POWERGRID Badarpur S/s. Subsequently, it was

also learnt that the temporary tappings have been removed.

However, there has been no improvement in service of the dedicated feeder sincefrequent power interruption still continues to take place on account of load

shedding.

ASEB (CAEDCL) may kindly treat the above-said issue with priority & take

necessary action for ensuring uninterrupted power supply through the 11 KV

dedicated feeder connected to POWERGRID Badarpur Substation.

T h e m a t t er w a s r e f er r ed t o Pr o t e ct i o n Co -O r d i n a t i o n s u b -Co m m i t t e e M eet i n g(PCCM).

D.16 Continuous violation of ATC/TTC limits due to overdrawal by constituents urgent requirement of Pallatana generation :

NERLDC informed that ATC/TTC limits of ER-NER corridor is being violated

continuously due to sustained over drawal by constituents resulting in insecure

operation of integrated grid. Less availability of power within the region is the root

cause of this problem. All concerned are requested to co-operate for secure

operation of grid by maintaining drawal as per schedule. At the same time

Generation at Pallatana is urgently required at this juncture to save the situation.

T h e Su b Co m m i t t e e n o t e d a n d c o n s t i t u e n t s a r e r e qu e st e d t o co -o p er a t e w i t h

NE RL D C a n d f o l l o w t h e d r a w a l s ch e d u l es f o r s ec u r e op er a t i o n o f g r i d .


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(LA, CT, CVT/PT, Isolator, CB, Earth Switch, Wave Trap etc) as these are required

for study purpose.

I t w a s a g r e ed t h a t t h e d e t a i l d a t a c ol l ec t ed d u r i n g p r o t e ct i o n a u d i t m a y be

u t i l i z ed f o r r e f er en c e .

D.21 VSAT communication system for RC - SLDCs:

During the 76th OCC meeting, NERLDC informed that due to supply of sub-

specification item, the VSAT order will be cancelled & fresh tender will be initiated.

In the meantime POWERGRID is establishing a State-of-the-Art optical fiber based

communication facility for the entire country connecting all RLDCs, NLDC &

SLDCs. In view of this the process of retendering of VSAT communication system

for four RC-SLDCs is being dropped to avoid duplication.

T h e S u b -Co m m i t t e e n o t ed a s a b o ve .

D.22 Any Other Item:

D.23.1 Additional agenda items:

1. Open cycle generation of AGBPP:

The following set of meters is used for calculation of open cycle generation of

AGBPP.

KT-03 NP-5804-A 0150 2000.0000 KATHALGURI GT-1KT-04 NP-5805-A 0150 2000.0000 KATHALGURI GT-2KT-05 NP-5806-A 0150 2000.0000 KATHALGURI GT-3KT-06 NP-5807-A 0150 2000.0000 KATHALGURI GT-4KT-07 NP-5818-A 0150 2000.0000 KATHALGURI GT-5KT-08 NP-5819-A 0150 2000.0000 KATHALGURI GT-6KT-09 NP-5820-A 0150 2000.0000 KATHALGURI GT-7KT-10 NP-5822-A 0150 2000.0000 KATHALGURI GT-8KT-11 NP-5823-A 0150 2000.0000 KATHALGURI GT-9

There are 3 modules with set of 3 meters viz.

Module-1: NP-5820-A (Steam turbine 1); NP-5804-A (Gas turbine 1) and NP-5805-A

(Gas turbine 2)


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(Gas turbine 4)


(Gas turbine 6)

Open cycle generation is calculated by assuming that the plant is operating in open

cycle whenever reading of meters installed with the steam is zero and there is some

reading on either of the gas turbines for each module. However, sometimes reading

of the steam turbine is not available and in such case, it is assumed that the steam

turbine is under shut-down/ maintenance and the same are being treated as open

cycle mode unless it is reported that meter is faulty.

Considering the recent hearing at CERC, open cycle mode of operation may be

required to be discussed in OCC/CC meetings and RPC Secretariat may be required

to certify the open cycle generation for each month. The following points are

suggested for deliberation in respect of open cycle generation of AGBPP:

1) The monthly percentage figures indicated in the Regional Energy Account

are indicative of open cycle generation for that month and it has no

commercial implication until the same has been agreed in OCC / CC

meetings.

2) In case of emergency situation, NEEPCO may intimate NERLDC/ NERPC

the requirement to operate in open cycle mode.

3) The healthiness, correctness and present status of the set of meters used for

calculation of open cycle generation should be jointly verified by

NEEPCO/PGCIL and APDCL.

4) Whenever the reading of any of the above set of meters used for calculation

of open cycle generation is un-available due to any reason, the reason

should be sent to NERLDC/ NERPC immediately. If the reason of non-

availability is not sent to NERLDC/ NERPC, the same may be treated as

operation in combined cycle mode.

The issue was deliberated in 19th Commercial Co-ordination Committee Meeting

held at Guwahati and members agreed the following points.

1) NEEPCO should not claim commercial benefits arising out of certification

from RPC Secretariat unless the same is approved in OCC/CC forums.


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2) RPC Secretariat will not mention open cycle generation certification of

AGBPP in the monthly REAs henceforth; however, the same will be

depicted as open cycle generation of AGBPP for the month which can be

used for billing purpose only after approval in OCC/CC/PCC forum.

3) Before operating in open cycle mode, NEEPCO should inform NERLDC

about operation in open cycle mode. The reason/urgency and tentative

duration should be intimated.

4) NERLDC should intimate beneficiaries about open cycle operation of the

plant. Beneficiaries may not like to buy such power at a higher price.

Moreover, since scheduling of generation is done on station basis and not

unit basis, scheduling of generation is not feasible unless scheduling is

done on unit basis.

5) As RPC Secretariat is certifying open cycle generation of combined cycle

plants in other regions, the same will be required to be certified by NERPC

Secretariat. The issue is brought to the members for deliberations to find

out a suitable method of certifying open cycle generation for combined cycle

plants.

T h e S u b -Co m m i t t e e n o t e d a n d t h e m a t t e r w i l l b e d e l i b er a t ed i n O CC/ CC f o r u m

a f t er CE RCs h ea r i n g on A p r i l 9 , 2 0 1 3 .

2. Representation in OCC/CC meetings:

The issue was deliberated in 19th Commercial Committee Meeting and it was

suggested to include representation of commercial personnel in OCC forum and vice

versa for CC forum.

T h e Su b -Co m m i t t e e a g r ee d t o t h e s u g g es t i o n o f C C M ee t i n g .

D.23.2 Agenda By AEGCL:

1. In many occasions, it has been observed that scheduling of ISGS like

Ranganadi and Kopili were increased for very short time period. In general in

between 19:45 hrs to 20:00 hrs, the increased quantum is around 50 to 70 MW.

So, it is very difficult to manage the load for that said period as we can neither

utilize that power for such a brief period nor can we show under drawal at


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20:00 hrs as we always have to impose heavy load shedding. This will reflect the

erratic picture of our peak loading.

CGM (S L D C), A EG CL e x p l a i n e d t h e s i t u a t i o n c i t i n g t h a t s u d d e n i n c r e a s e o f

l o a d t o 5 0 t o 7 0 M W i n a t i m e -b l oc k a n d r e d u c i n g a g a i n i n t h e n e x t b l oc k i s

n o t f e a si b l e . B es i d e s, si n c e t h e s ch ed u l e i s a l r ea d y i n c r ea s ed b y c er t a i n

a m o u n t , t h e c or r esp on d i n g u n d er d r a w a l a t 2 0 : 0 0 h r s m a y b e i n t er p r e t ed a s

A ssa m h a v i n g s u r p l u s p ow er d u r i n g t h a t p er i o d , w h i c h i s n o t t h e r ea l

s i t u a t i o n a s l o a d s h e d d i n g i s i m p o s ed t o on t h e c o n s u m e r s . H e r eq u e st e d

N ER L D C t o l o o k i n t o t h e i s s u e a n d a v o i d s u c h f l u c t u a t i o n s i n t h e sc h e d u l e s o

t h a t p r o p er d r a w a l sc h ed u l e c a n b e i m p l e m en t ed b y S L D Cs .

T h e s u b -c o m m i t t e e n o t e d a n d r eq u e st e d N E RL D C t o l o o k i n t o t h e m a t t er f o r

r em e d i a l m ea s u r es . T h e s a m e w i l l b e r e v i ew e d i n n e x t O CC m e et i n g .

2. Due to low generation of hydro power station and further reduction of TTC/ATC

at the NER-ER corridor, the power scenario of NER is horrible nowadays. In this

connection, Member Secretary (I/C) of NERPC has been requested to discuss

the issue when all the beneficiaries of NER will take stable power from

Pallatana.

CG M , S L D C, A ss a m em p h a s i z ed t h e n e ed f o r e n h a n c em en t o f T T C / AT C i n E R - NE R c or r i d o r s o t h a t s h o r t t e r m p u r c h a s es ca n b e m a d e by A ssa m f r o m

o u t s i d e t h e r eg i o n a n d a c u t e sh o r t a g e o f p o w e r i n A s sa m c a n b e r el i ev ed t o

so m e ex t e n t a n d t h e m i ser y o f p er s on s w o r k i n g f o r d i s t r i b u t i o n s y st e m w i l l

b e r e d u c ed .

T h e m a t t er h a s a l r ea d y b ee n d i s c u s sed a t i t e m N o .D .4

T h e su b -c om m i t t e e a l so su g g est e d A s sa m t o h a v e a b i l a t er a l t i e u p w i t h

Tr i p u r a t o p u r c h a s e t h e S m a l l q u a n t u m o f p ow er , w h i c h i s bei n g s ol d b y

Tr i p u r a t o ou t si d e t h e r eg i o n t h r o u g h Po w er E x c h a n g e .

3. It is understood that 2 nos of 160 MVA 220/ 132 kV ATS have been installed at

Byrnihat (PG) sub-station to evacuate power through 132 kV network. In this

regard, Assam would like to know from Meghalaya whether any provision has


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been kept to tap the power either at Kahilipara or at Sarusajai through this 132

kV network.

S E (S L D C), Me. ECL i n f o r m ed t h a t t h er e i s n o ex i s t i n g a r r a n g em en t t o t a p

p o w e r a t t h e a b o v e s t a t i o n s . A E G C L w a s r e q u e s t e d t o c o n t a c t t h e

t r a n s m i s si o n w i n g o f Me. ECL f o r f u r t h er i n f or m a t i o n s/ d et a i l s.

D.23.3 Agenda By NHPC:

ED, NHPC informed that the low voltage (121kV to 123kV) at Loktak 132kV bus

is creating problem for auxiliary system and motors are likely to be damaged

due to low voltage.

GM, NERLDC informed that the voltage is well within the tolerable band of

CERC. The matter was discussed earlier in OCC meeting. The committee

requested NHPC to submit details regarding the low voltage problem to NERLDC

for further study and matter will be deliberated in next OCC.

D.23 Date & Venue of next OCC meeting

It is proposed to hold the 84th OCC meeting of NERPC on 9th April, 2013

(Tuesday). As per roaster, Mizoram will be the host for 84th OCC meeting. The exact

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 83rd OCC meeting held on 11/03/2013

SN Name & Designation Organization Contact No.

1. Sh. Tarik Mize, EE(E), SLDC Ar. Pradesh 09436059758

2. Sh. N.C. Das, CGM, SLDC Assam

3. Sh. P.K. Sarma, GM (Com) Assam

4. Sh. B Bordoloi, DGM, SLDC Assam

5. Sh. A. K. Saikia, AGM Assam 09864116176

6. Sh. K. Goswami, AGM, APDCL Assam 09435041494

7. Sh. Shantikumar, EE (SCD-I) Manipur 09436022381

8. Sh. Th. Kamini M Singh, EE (TCD-I) Manipur

9. Sh. B.C. Sharma, EE (SCD-II) Manipur 09436020911

10. Sh. A. Kharpan, SE (SLDC) Meghalaya 09436117802

11. Sh. D.J. Lyngdoh, AEE, SLDC Meghalaya 09863063375

12. No Representative Mizoram

13. No Representative Nagaland 09436002696

14. Sh. B. Debbarma, DGM (SO) Tripura 09436450501

15. Sh. Debabrata Pal, Sr. Mgr. Tripura 09436500244

16. Sh. T. S. Singh, GM NERLDC 09436302717

17. Sh. B. Medhi, Dy. Mgr. NERLDC 09436335376

18. Sh. P. Kanungo, DGM NERTS 0943630282319. Sh. S.I. Singh, DGM PGCIL, Imphal 09436035172

20. Sh. B. Goswami, Sr. Mgr. (E) NEEPCO 09436163983

21. Sh. D. Chattopadhyay, GM (O&M) NHPC

22. Sh. B.S. Karn, CE (Loktak) NHPC

23. Sh. R. C. Singh, Mgr.(E) NHPC 09436894889

24. Sh. H. Deshmukh, Engr (E) NHPC 09402880217

25. Sh. Pranay Kumar, Engr. (E) NHPC

26. Sh. R.K. Tanzing, Engr. (E) NHPC 0940288021727. Sh. A. Mukherjee, JE NHPC 09436894887

28. Sh. Mukul Banerjee, GM (Plant) OTPC 09899354722

29. Sh. S.K. Ray Mohapatra, MS I/C NERPC 09818527857

30 Sh.B. Lyngkhoi, SE (O) NERPC 09436163419

83rd OCC Minutes Final

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