77th occ minutes

8/13/2019 77th OCC Minutes

1/29

No. NERPC/OP/OCC/2012/5 0 0 5 - 3 4 Date: 21stSeptember, 2012

To,1. Managing Director, APDCL, Bijuli Bhawan, Guwahati 781 0012. Managing Director, AEGCL, Bijuli Bhawan, Guwahati 781 0013. Director (Distribution), Me. ECL, Lumjingshai, Short Round Road,Shillong 793 0014. CGM, (LDC), SLDC Complex, AEGCL, Kahelipara, Guwahati-781 019 5. Chief Engineer (WE Zone),Department of Power,Govt. of Arunachal Pradesh,Itanagar- 791 111 6. Engineer-in-Chief (P&E), Department of Power, Govt. of Mizoram, Aizawl 796 0017. Chief Engineer (P), Electricity Department, Govt. of Manipur, Keishampat, Imphal 795 0018. Chief Engineer (P), Department of Power, Govt. of Nagaland, Kohima 797 0019. General Manager, TSECL, Agartala 799 00110.ED (O&M), NERTS, PGCIL, Dongtieh-Lower Nongrah, Lapalang, Shillong -793 00611.ED (O&M), NEEPCO Ltd., Brookland Compound, Lower New Colony, Shillong-793003 12.ED (Commercial), NEEPCO Ltd., Brookland Compound, Lower New Colony, Shillong-79300313.ED (O&M), NHPC, NHPC Office Complex, Sector-33, Faridabad,Haryana-12100314.AGM, NERLDC, Dongtieh-Lower Nongrah, Lapalang, Shillong -793 006 15.DGM (C&M), OTPC, 6thFloor, A-Wing, IFCI Tower -61, Nehru Place, New Delhi - 11001916.Member Secretary, ERPC, 14 Golf Club Road, Tollygunge, Kolkata-70003317.Chief Engineer, GM Division, Central Electricity Authority, New Delhi 110066

Sub: Minutes of the 77thOCC Meeting held on 13thSeptember, 2012 at Guwahati.

The Minutes of the 77thOCC Meeting of NERPC held on 13.09.2012at Hotel GrandStarline, Guwahati is enclosed for favour of kind information and necessary action please .

The minutes is also available on the website of NERPC www.nerpc.nic.in

Encl: As above

/Yours faithfully,

(. /B. Lyngkhoi ) / Superintending Engineer (O)

Copy to:

1.Chief Engineer, AEGCL, Bijuli Bhavan, Guwahati - 7810012.Chief Engineer, APGCL, Bijuli Bhavan, Guwahati - 7810013.S.E. (Trans. & Dist), MeSEB Lumjingshai, Short Round Road,Shillong 793 0014.Head of SLDC, MeSEB, Lumjingshai, Short Round Road,Shillong 793 0015.Head of SLDC, Department of Power,Govt. of Arunachal Pradesh,Itanagar- 791 1116.A.C.E. (Gen & Trans), Department of Power, Govt. of Nagaland, Kohima 797 001

7. Head of SLDC, Department of Power, Dimapur, Nagaland8. A.C.E. (Power-I), Electricity Department, Govt. of Manipur, Keishampat, Imphal 795 0019. Head of SLDC, Electricity Department, Govt. of Manipur, Keishampat, Imphal 795 00110.S.E. (Trans & Dist), Department of Power, Govt. of Mizoram, Aizawl 796 00111.Head of SLDC, Department of Power, Govt. of Mizoram, Aizawl 796 00112.Head of SLDC, TSECL, Agartala 799 00113.Chief Engineer(Elect), Loktak HEP,Vidyut Vihar, Kom Keirap, Manipur- 795124

Government of IndiaMinistry of Power

North Eastern Regional Power Committee

- . Meghalaya State Housing Finance Co-Operative Society Ltd. Building

, 793003Non rim Hills Shillon 793003.

ISO 9001:2008

Ph. No: 0364 - 2520050

Fax No: 0364 - 2520030


2/29

North Eastern Regional Power Committee

MINUTES OF THE 77th

OPERATION COORDINATION SUB-COMMITTEE MEETING

OF NERPC

Date : 13/09/2012 (Thursday)

Time :10:30 hrs

Venue :Hotel Grand Starline, Guwahati.

The List of Participants in the 77thOCC Meeting is attached at Annexure I

The meeting was started with welcome address by Shri A. K. Mishra, Member

Secretary I/C, NERPC. He welcomed all the participants to the 77 thOCC meeting.

He briefed about the power supply position during the month of August, 2012 and

informed that all the grid parameters are within the permissible limits. He also

stated that with the commissioning of Pallatana GBPP the behavior of the NER grid

will become more complex and hence all the constituents should cooperate with

NERLDC for smooth operation of the system. Further, he informed about the

recommendation of Enquiry Committee on Grid Disturbance that occurred on the

30th& 31stJuly, 2012. He requested all the participants to actively participate in

the discussion for fruitful outcome.

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

take up the agenda items for discussion.

CONFIRMATION OF MINUTES OF 76th MEETING OF OPERATION SUB-COMMITTEE OF NERPC.

SE(O), NERPC mentioned that the minutes of the 76th OCC meeting held on 8th

August, 2012 at Guwahati were circulated vide letter No.

NERPC/OP/OCC/2012/4479-4512 dated 17thAugust, 2012.

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


3/29

Minutes of 77thOCC meeting held on 13thSeptember, 2012 at Guwahati

2

No obse r v a t i o n s or c om men t s we r e r ec ei v ed f r om a ny o f t h e con s t i t u en t s , t h e

m i n u t e s o f 7 6 t hOCC meet i n g w as con f i r m ed .

SE (O), NERPC request ed NERLDC t o g i ve t h e p r esen t a t i on abou t t h e g r i d

p er f o rma n c e o f NER du r i n g t h e mon t h o f A u g u st , 2 0 1 2 .

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 AUGUST, 12

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

August, 2012 are given below:

i) Average frequencyduring August, 2012 was 49.95 Hz as compared to 49.70 Hzin July, 2012.

ii) Minimum frequency in August, 2012 was 48.82 Hz (20.08.12 at 10:44 hrs) ascompared to 48.79 Hz recorded in the previous month.

iii) Maximum frequency was 50.65 Hz (02.08.12 at 08:02 hrs), as compared to50.21 Hz in July, 2012.

iv) System frequencyremained within permissible range of 49.5 Hz to 50.2 Hz for90.70 % of the time, below 49.5 Hz for 1.53 % and above 50.2 Hz for 7.77 % of

the time as compared to 74.70 %, 23.32% and 1.98 % respectively in the previous

month.

v) Regional peakdemand in August, 2012 was 1960 MW as compared to 1946 MWin July, 2012, an increase of 0.71 % over the previous month.

vi) Regional peak availability was 1789 MW as compared to 1762 MW in previousmonth, an increase of 1.53 % over the previous month.

vii)Energy requirementwas 1071.17 MUs in August, 2012 compared to 1046.16MUs in July, 2012, an increase of 2.39 % over the previous month.

viii)Regional energy availabilitywas 1004.39 MUs compared to 973.00 MUs in theprevious month, an increase of 3.23 % over the previous month.

ix) Rise in demand met was recorded in Manipur (5.83%), Nagaland (2.78%),Assam (2.19%) & Mizoram (1.98%) over the previous month.

x) Drop in demand met was recorded in Ar. Pradesh (6.15%), Meghalaya (1.32%),& Tripura (0.13%) over the previous month viz. July, 2012.


4/29


3

xi) Over Voltages at 400 kV substations were observed at Misa and Balipara, wheremaximum voltage observed were 422 and 420 kV respectively. No over voltage at

220 kV S/S was observed.

xii)No over Voltages were observed at 132 kV S/S.xiii)No under Voltages were observed at 400 kV S/S, 220 kV S/S. Under voltage,

observed at 132 kV S/S at Aizawl, was 115 kV.

xiv)Regional Generation & Inter-regional Exchangesduring the month of August,2012 compared to July, 2012 are given below:

SN Parameter August, 2012 July, 2012

REGIONAL GENERATION & INTER REGIONAL EXCHANGES (in MU)

1 Total Generation in NER (Gross) 945.077 944.701

2Total Central Sector Generation (Gross) 604.102 628.115

Total State Sector Generation (Gross) 340.975 316.586

3

Inter-Regional Energy Exchanges

(a) NER - ER 13.74 23.60

(b) ER - NER 106.82 85.26

(c) Net Import 93.08 61.66

Th e Sub -comm i t t ee no t ed a s above.

FOLLOW UP ACTION

C.1 Installation of new Under Frequency Relays (UFRs) in NER systems andconstituent-wise quantum of load relief as recommended by the sub-committee:

During 73rd OCC, Manipur representative had informed the work is in progress

and installation of UFRs in Manipur would be completed by May, 2012.

The status could not be updated as Manipur representative was not present. The

Sub-Committee requested NERPC Secretariat to take up the issue with DoP,

Manipur.

During Special Committee meeting Manipur representative had informed that the

UFRs had been procured and the installation work was going on.


5/29


4

Manipur representatives informed that they want to install UFR in 132 kV Imphal-

Imphal line. NERLDC suggested for choosing radial feeders for the purpose.

Manipur informed that installation work will be completed by September, 2012.

Th e sub -Comm i t t ee no t ed a s above.

C.2 Status of 132 KV Kopili Khandong 2ndCkt:In the 72nd OCC meeting POWERGRID had informed that the job was taken up by

them during the approved shut down period from13.01.2012 to 23.01.2012. But,

on 23.01,2012 a fatal accident had occurred during the stringing of conductor for

which one tension tower before dead end tower got totally damaged. Subsequently

POWERGRID restored the Line # 2 on 23.01.2012 and Line # 1 on 23.01.2012

temporarily on old tower as per the existing arrangement.

POWERGRID had arranged the tower from MeECL and applied shut down during

the period from 23.04.2012 to 04.05.2012 for Line # 1 and from 06.05.2012 to

14.05.2012 for Line # 2 to carry out restoration on permanent basis. The job was

to be completed by 15th May 2012.

During 74th OCC meeting, POWERGRID had informed that they have availed

shutdown from 15.05.12 to 24.05.12 to complete the above work and started

erection of tower. Unfortunately the work had to be postponed due to mismatch of

foundation and the same was to be completed by 20thJuly, 2012.

During the 75th OCC meeting, AGM, NERTS had informed that the work was

postponed due to heavy rain in the area and the same would be completed soon.

During 76th OCC meeting, POWERGRID had again informed that the work was

delayed due to heavy rain at project site, however the work would be completed by

12thAugust, 2012.

CM, POWERGRID informed that the work was completed on 11thAugust, 2012.



6/29


5

C.3 Powermap & Single Line Diagram (SLD) in NER.In the 73rd OCC meeting, NERPC once again requested all Constituents,

particularly SLDCs, to submit the latest / updated Powermap (showing

geographical location, generating stations and interconnecting lines) & SLD of their

state covering 132kV and above voltage level as requested during the 71st

OCCmeeting.

As suggested by the Sub-committee in 74thOCC meeting, NERPC had uploaded

the current single line diagram and powermap of the NER constituents in NERPCs

website. Constituents were requested to download the same form NERPCs website

and do necessary modification/updation, if any.

During 75thOCC meeting, Assam intimated that they have submitted the requisite

information to NERLDC. MS I/C, NERPC stated that the editable soft copy of therespective SLD and Power map will be circulated to all the constituents so that

they can correct/modify the diagrams and submit to NERPC. Further, the

committee decided to follow the CBIP colour coding for the above diagrams.

AGM, POWERGRID stated that the upcoming Sub-stations and lines may be

considered for the compilation of the above diagrams. MS I/C, NERPC welcomed

the suggestion of POWERGRID and requested to provide the necessary details of

new/up-coming projects for incorporation.

Assam intimated that they are getting some difficulties in editing the editable

formats. It was decided that un-grouped editable file of SLDCs and Power map will

be uploaded in the website/sent by e-mail so that the utilities can update their

respective data and Power maps.

A l l t h e con s t i t u en t s ag r eed t o subm i t t h e cor r ec t ed SLDCs and Powe r m ap

t o NERPC a t t h e ea r l i es t .

C.4 Submission of data required for development of Power Atlas of NER & statesof NER

NERLDC had sent letters to power utilities of NER for development of Power Atlas of

NER & states of NER by June, 2012 by NERLDC. The status given by NERLDC in

74thOCC meeting was as under:


7/29


8/29


7

C.5 Status of completion of ongoing Transmission Lines in NER.During the 73rd OCC meeting, NERPC Secretariat had circulated the proforma

regarding the status of various ongoing transmission schemes being

executed/implemented by POWERGRID/States/Other Agencies.

SE(O), NERPC informed that POWERGRID has submitted the above data. He

stressed to other constituents to submit the status of their ongoing transmission

lines. Member Secretary I/C requested the constituents to furnish the details as

per proforma so that the status can be updated to constituents in every OCC

meeting.

All constituents have submitted the data except Mizoram and Manipur. Committee

requested them to submit the data at the earliest.

Man i p u r a n d M i z or am a g r e ed t o f u r n i sh t h e st a t u s .

C.6 Status of Generation Projects in NERDuring the 73rd OCC meeting, NERPC Secretariat had circulated the proforma

regarding the status of Generating units to be commissioned/expected to be

commissioned by Central Utilities/States/Other Agencies.

During 75th OCC meeting, MS I/C stressed all the constituents to submit the

above status as it will help the sub-committee to keep track of various generation

projects and it will help in operation planning also. NEEPCO informed that they

will furnish the data in respect of their projects in the next OCC meeting.

TSECL and NEEPCO had submitted the status of their ongoing generation

projects.Member Secretary I/C requested other constituents to furnish the details

as per proforma so that the status can be updated to constituents in every OCC

meeting.

A l l t h e con s t i t u e n t s a r e r eque st e d t o f u r n i s h a s agenda i t em i n ever y OCC

mee t i n g .


9/29


8

C.7 Early revival of 3 numbers of 20 MVA Transformers at KopiliAssam observed that right from the time of the commissioning of 160 MVA Auto

transformer of Power Grid at Kopili, the existing 3 numbers of 20 MVA, single phase

transformers supplied by NEEPCO are not in working condition till today.

Therefore, NEEPCO was requested to make necessary arrangement for revival of the

above transformers for strengthening of the grid security at an early date.

The NEEPCO representative had informed that the above said transformers were

not charged since March, 2011.

The committee had suggested NEEPCO to keep the 3X 20 MVA transformers in

charged condition so that it could be connected to grid in case of outage of 160

MVA Autotransformer.

During 75th OCC meeting, NEEPCO stated that after completion of Shutdown of

Kopili-Khandong line, the transformers would be test charged after necessary oil

filtration.

During 76thOCC meeting, NEEPCO had informed that the oil filtration work would

be completed within seven (7) days. Further, the Committee had requested

POWERGRID to study parallel operation of the 3x20 MVA transformers with the

existing Kopili ICT.

NEEPCO informed that the 3x30 MVA Transformers was successfully charged from

220 kV side on 8thSeptember, 2012.

SE (Com), NERPC informed that these transformers should not be kept in charged

condition for long period without load and other possibilities of utilization of these

regional assets should be explored. He also suggested for loading of 3x20MVA

transformer (keeping 160MVA transformer out of circuit) under planned shutdown

condition of one of the D/c line between Kopili and Khandong limiting the line

loading to safe operation limit of transformer.

CM, POWERGRID stated that this transformer can be operated locally in parallel or

it can feed radial load. Further, he informed that the parallel loading of transformer

will only be possible if the percentage impedance of the above transformer bank is

within the permissible limit otherwise it will limit the loading of 160 MVA ICT.


10/29


9

CM, POWERGRID stated that this transformer can be operated in isolation to feed

radial load. Further, he informed that the parallel loading of transformer is possible

if the percentage impedance of the both transformer bank is within the permissible

limit, otherwise the loading of 160 MVA ICT will be limited.

The Committee inquired from NEEPCO about the percentage impedance of both

transformers. NEEPCO agreed to provide the information in the next OCC meeting.

The Committee agreed and requested POWERGRID to explore for more possibility

for utilizing these transformers as these are regional projects and cannot be kept

idle. It was also decided that possibility will be explored for charging the ICT along

with 132 kV Kopili Khandong ckt-I in the event of shut down of 132 kV Kopili

Khandong ckt-II.

Th e sub -Comm i t t ee no t ed as a bove.

C.8 Running of Pallatana one unit in full capacity for 72 hrsIn the meeting on 24.07.12 OTPC had informed that U-I will be put on commercial

operation in the last week of August, 2012. For this continuous running of the unit

at full capacity(363 MW) will be required for 72 hrs. It was decided that the matter

will be deliberated in next (76th) OCC meeting for finalizing quantum of backing

down required at different stations in 132 kV pocket and acceptance of the utilities

in this regard for finalization of modus operandi.

During 76thOCC meeting, NERLDC presented the detail system study report for 72

hours continuous run Pallatana module-I. The detail study was carried out for two

cases: Off-Peak (03:00 Hours) and Peak (20:00 Hours) based on evacuation of

maximum power up to 350 MW and case study of tripping of Pallatana module.

From the report it was found that during off-peak hours Tripura, AGTPP and

Loktak has to back down their generations.

On telephonic discussion with OTPC during the OCC meeting, it was understood

that Palatana unit-I would start trial run from mid August and about 30-40 MW

will be injected to Grid as Infirm power. Thereafter, 72 hrs full load pre-

commissioning test was expected to be done by mid September. About 363 MW


11/29


10

continuous load would have to be connected to the Palatana system during such

test by reducing Tripura state generation, AGTPP and LOKTAK generation.

AGM, TSECL stated that beneficiary state would be required to overdraw power as

their drawl scheduled will be reduced to the extent AGTPP and LOKTAK generation

is backed down. In addition Tripura would have to maximize their drawal with

backing down of own State generation. In view of above it was decided to have

separate meeting to study the pre-commissioning test arrangement and

commercial impact of affected utility. Further, it was discussed that with the

commissioning of Palatana project fault level of 132 KV pocket of NER would

substantially go high. Existing protection system and impact of likely fault at

various condition of Palatana operation would have to be studied at Transmission

network and Generating stations connected at 132 KV pocket of both state and

central sector. It was decided that PGCIL would conduct required study and reportwould be placed to next combined OCC and protection committee meeting.

POWERGRID had agreed.

During 76th OCC meeting, the committee expressed concern about the non-

representation of OTPC in the OCC meeting and felt that this issue should be

deliberated in the presence of OTPC representatives in the next OCC meeting.

DGM, OTPC informed that the gas turbine firing has started on 13.09.12 and themachine will be synchronized to the grid on 29th September, 2012 after passing

through various stages of operation as per the manufacturers guidelines. After

synchronization infirm power of about 40 MW (approximately) will be injected into

the grid. Then machine will run on Full Speed No Load (FSNL) for seven (days).

After that steam turbine rolling will start and the module I will come into

operation w.e.f. 29.09.2012. Since there is no bypass arrangement in the modules,

the machine cannot run under open cycle mode. In initial phase, the complete

module will generate around 150-160 MW and slowly generation will ramp upto

363 MW, and ultimately machine has to run continuously under full load for 72

hours to declare COD.

NERLDC gave the detail presentation for evacuation of maximum power from

Pallatana taking into account the surge impedance loading of the line as limitation,

as advised by NLDC after grid disturbance.


12/29


11

The presentation is enclosed at Annexure C.8. The detail study was carried out for

following scenarios:

1. Evacuation of Maximum power from Pallatana during 0300 Hrs withoutbacking down of other generation

2. Evacuation of 360 MW (Ex-PP) from Pallatana during 0300 Hrs with backingdown of other generation

3. Case study on Reduction of generation of Pallatana from 360 MW during0300 Hrs

4. Case study on tripping of 360 MW (ex-PP) generation at Pallatana GBPPduring 0300 Hrs

5. Evacuation of Maximum power from Pallatana during Peak Hrs withoutbacking down of other generation

6. Evacuation of 360 MW (Ex-PP) from Pallatana during Peak Hrs with backingdown of other generation

7. Case study on Reduction of generation of Pallatana from 360 MW duringPEAK hours

8. Case study on Tripping of Palatana GBPP during Peak Hrs from an initialgeneration of 360 MW)

During the presentation by NERLDC, it was observed that in absence of 400kV

Silchar-Byrnihat line, tripping of machine at Palatana under full load condition

(i.e.363MW), during peak and off peak hours, will have adverse impact on the NER

system leading to overloading of number of lines and ICT at Misa. Further,

NERLDC requested Assam and Meghalaya that 132 kV Panchgram-Lumshnong

line should be ready before the synchronization of the Pallatana Machine on

29/09/12. Assam informed that 90% of Assam portion is ready and the rest will be

completed very soon. MeECL informed that they would communicate the actualprogress after getting information from the site.

AGM, TSECL informed that during trial operation NERLDC should check whether

the 132 kV NER system can sustain generation of 200 MW and more. Further, he

suggested that the machine may be synchronized with grid and during the

operation close co-ordination with NERLDC is required and there should be proper

Load-Generation Stabilization.


13/29


12

Assam emphasized that the NER system cannot sustain generation of 363 MW

from Palatana without commissioning of 400 kV Silchar-Byrnihat line. So, we have

to wait for commissioning of this line and we should go step by step for

synchronization with the grid with full generation of 363MW. However, OTPC can

generate 200 MW as decided in previous meetings till 400kV Silchar-Byrnihat line

is ready.

POWERGRID informed that the commissioning schedule of 400 kV Silchar

Byrnihat is January, 2013.

CEA representative stated that at present NER system is not strong enough to take

the full generation of OTPC and as per CEA guidelines commercial operation of

machine can be declared only after 72 hours of continuous generation under full

load condition. So, OTPC should wait till the commissioning of 400kV Silchar-

Byrnihat line. The injected power will be infirm power, if COD is not granted.

After detailed deliberation the Committee agreed to allow for synchronization of

Pallatana Machine with ex-bus generation of 200 MW due to system constraint.

After stabilization of machine and proper synchronization with the grid, full loading

upto 360 MW would be considered.

But the representative of OTPC informed that as a technical requirement for trail

run, the machine needs to go upto full load of 363MW and COD cannot be

declared without continuous operation under full load for 72 hours.

Taking into account the prevailing situation and requirement of additional power

in coming Durga Puja, the Committee ultimately agreed with OTPCs proposal to

go for synchronization process and continuous operation under full load for 72

hours required for declaration of COD subject to OPTC provide their detail action

plan to NERLDC well in advance so that necessary planning for backing down of

generation and change in drawl schedule of constituents can be finalized by

NERLDC before hand as the existing transmission system is not healthy to absorb

any abnormality due to tripping of Palatana generating Unit, while running under

full load (363MW).



14/29


13

C.9 SPS scheme for PallatanaIt 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 76thOCC 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 protection

schemes 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.

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 (refer Item No. C.10; Annexure C.10) 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.



15/29


14

C.10 Implementation of islanding scheme in NERFor 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. 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. The

presentations of both the proposals are enclosed at Annexure C.10.1and C.10.2.

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

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. The list of radial lines identified for above purpose along with

the load relief is enclosed at Annexure C.10.

All constituents agreed to co-operate with NERLDC during emergency.



16/29


15

C.11 UFR Relay OperationInformation regarding UFR operation at the time (13:00 hrs) of NR-ER-NER

disturbance on 31st August, 2012 was requested from the Utilities. Except Tripura

no other utility had furnished the same.

NERLDC informed that all constituents have submitted the required information


C.12 Switching Schemes:

During 76thOCC meeting, DGM, NERLDC requested all the utilities to submit their

switching schemes to NERLDC along with a copy to NERPC.

A l l c o n st i t u e n t s a g r e ed t o f u r n i s h t h ei r sw i t c h i n g s ch eme.


17/29


16

D. N E W I T E M S

D.1 Proforma for Operational Statistics -NERPCThe 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.

Th e oper a t i o n a l s t a t i c s wer e shown i n t h e p r es en t a t i o n b y NERLDC.


D.2 State-wise anticipated peak demand/requirement, shortage for September,October, November December- 2012 & January- 2013.

Th e s u b-Comm i t t ee r evi ew e d & f i n a l i z ed t h e a n t i c i p a t e d p ea k

demand / e ne r g y r e qu i r emen t / A v a i l a b i l i t y f o r t h e mon t h s o f Sep t embe r ,

Oc t o ber , Novem ber , Decembe r - 20 12 & Ja nu a r y -2 0 13 .

A. Peak Demand

S.No. State

Peak

Demand

(MW)

Sep 12

Peak

Demand

(MW)

Oct 12

Peak

Demand

(MW)

Nov 12

Peak

Demand

(MW)

Dec 12

Peak

Demand

(MW)

Jan 13

1 Ar. Pradesh 110 110 100 100 105

2 Assam 1100 1150 1150 1175 12003 Manipur 105 110 100 100 105

4 Meghalaya 265 270 280 280 280

5 Mizoram 70 75 75 75 75

6 Nagaland 110 110 100 100 110

7 Tripura 230 250 240 240 240

Region 1990 2075 2045 2070 2115


18/29


19/29


18

already written a letter to Mizoram and Meghalaya with a copy to NERPC for

additional Power like previous years and has also requested NERLDC for

necessary arrangement to meet the power demand of about 250 MW during

Puja.

AGM, TSECL informed that during Durga Puja Tripura requires 250 MW load.

He requested the other constituent States and NERLDC to help by providing

additional power during Durga Puja time to meet their load requirement.

Mizoram stated that they are waiting for approval from their Power Department.

NERLDC presented the case studies pertaining to drawal of Tripura (without

considering Pallatana generation) during Durga Puja which is enclosed at

Annexure D.3.2. NERLDC also informed that in real time it may not be possible

to provide the extra quantum of power, purchased from Meghalaya, to Tripura

due to system constraint. All constituents Assam, Meghalaya, Mizoram and

Manipur agreed to support Tripura during Durga Puja. It was also decided to

review the scenario in the next OCC after commissioning of Pallatana Unit.


3) Voice & Data communication including SCADA monitoring for real timeoperation in respect of Palatana project & its associated Transmission

system and its current status.

OTPC informed that the voice and data communication is ready upto Silchar

POWERGRID informed that they have received only one modem and second one

is yet to be received from OTPC. Further, they informed that the voice and data

communication link up to Silchar is complete and within a week remaining work

up to NERLDC, Shillong will be completed.

NERLDC informed that the communication system is to be established as per

the system requirement before the synchronization of Pallatana unit.


20/29


19

On enquiry by OTPC regarding data communication link in Tripura part,

POWERGRID informed that communication link from Pallatana to

Surajmaninagar and Udaipur will be done by POWERGRID and communication

link from Surajmaninagar and Udaipur to Tripura SLDC will be done by TSECL.

The Committee advised OTPC to resolve the matter of the communication system

with POWERGRID and Tripura before commissioning of the Units.


4)TSECL informed that the website of NERPC is not functioning properly as theyfound difficulty in downloading the REA, Meeting notice/minutes etc. on time.

The previous data are also not available.

SE (Com), NERPC clarified that the new website has been developed by NIC and

NERPC is also trying to upload the old data for the benefit of constituents. The

minutes of OCC, PCC & NERPC meetings, UI and REA data for last one year has

already been uploaded in new website. He assured constituents to take

necessary action for improvement in website and based on the feedback, the

matter will be taken up with NIC for further improvement.


D.4 Recommendations of Enquiry Committee on Grid Disturbance

After the major grid disturbance on 30th and 31st July, 2012, the enquiry

committee constituted under the Chairmanship of Shri A.S. Bakshi, Chairperson,CEA had submitted the report to Ministry of Power on 16th of August, 2012 and

report has been made available on website of Ministry of Power, Govt. of India

(www.powermin.nic.in).

As per the report the following recommendations are required to be implemented

by the NER constituents:


21/29


20

1) Review of Protection Systems

i. There is a need to review protection schemes. This Committee concurs withrecommendation of previous enquiry committees that a thorough third party

protection audit need to be carried out in time bound manner. This exercise

should be repeated periodically and monitored by RPCs.

ii. Till protection audit is taken up, there is need to take immediate review ofzone-3 philosophy in particular. Techniques are available to modify

characteristics of the relay so that it can distinguish between load

encroachment and faults. These techniques and other alternatives should be

explored immediately.

iii. The application of synchrophasor measurements from PMUs should beexplored for protection systems. There is also an urgent need to deploy Special

Protection System (SPS) in critical transmission elements. Also there is need

to make already approved SPS operational

iv. A complete independent audit of time synchronization of DRs, ELs and PMUsshould be carried out

2) Ensuring proper functioning of defense mechanism

All STUs should immediately enable under frequency and df/dt based load

shedding schemes. Central Commission should explore ways and means for

implementation of various regulations issued under the Electricity Act, 2003. Any

violation of these regulations can prove to be costly as has been the case this time.

RPCs need to take up the matter for compliance. In case non-compliance persists,

POSOCO should approach Central Commission.

3) Coordinated outage planning of transmission elements

Outage planning of inter-State and inter-regional transmission elements should be

carried out in a coordinated manner at RPC fora (say Operation Co-ordination sub-

committee of RPCs) in accordance with regulation 5 of Central Electricity Authority

(Grid Standards) Regulation, 2010 and Section 5.7.1 of Indian Electricity Grid


22/29


21

Code. In case need for emergency maintenance arises in between two meeting of

Operation Co-ordination sub-committee, NLDC and RLDCs should allow such

maintenance after carefully looking at prevailing system conditions under

intimation to RPC Secretariat.

4) Reactive power planning

In order to avoid frequent outages/opening of lines under over voltages and also

providing voltage support under steady state and dynamic conditions, installation

of adequate static and dynamic reactive power compensators should be planned.

5) Optimum utilization of available assets

i. An audit of devices such as HVDC, TCSC, SVC and PSS should be doneimmediately to ensure that their stability features are enabled. Further,

exercise of PSS tuning should be planned and implemented. Settings of these

dynamic stabilizing devices should be reviewed at appropriate intervals.

ii. Functioning of existing PMUs and availability of their output to RLDCs andaccuracy of time synchronization should be monitored on daily basis and, if

required, corrective actions should be taken on priority basis.

iii. Possibility of voltage collapse prediction, sensing global power systemconditions derived from local measurements may be explored

6) Deployments of WAMS

The synchrophasor based WAMS employing PMUs offer a wide applications for real

time monitoring and control of the system, specially under the dynamic conditions.

Adequate number of PMUs should be installed to improve the visibility and real

time monitoring of the system. Further the applications related to the

synchrophasor based wide area monitoring, protection and control should be

embedded in the system.

Possibility of voltage collapse prediction, sensing global power system conditions

derived from local measurements may be explored.


23/29


22

7) Implementation of islanding schemesEfforts should be made to design islanding scheme based on frequency sensing

relays so that in case of imminent grid failure, electrical islands can be formed.

These electrical islands can not only help in maintaining supply to essential

services but would also help in faster restoration of grid

8) Autonomy to Load Despatch CentresAs National Grid is on the horizon, homogenization of system operation philosophy

is need of the hour. The present organizational set up of Load Despatch Centres

need to be reviewed. System operation needs to be entrusted to Independent

System Operator (ISO). In addition, SLDCs should be reinforced and ring fenced for

ensuring functional autonomy.

Training and certification of system operators need to be given focused attention.

Sufficient financial incentives need to be given to certified system operators so that

system operation gets recognized as specialized activity.

9) Development of Intra-State transmission systemIntra-State transmission system needs to be planned and strengthened in a better

way to avoid problems of frequent congestion

10) Network visualizationThe Communication network should be strengthened by putting fibre optic

communication system. Further, the Communication network should be

maintained properly to ensure reliability of data at Load Despatch Cenres.

RTUs and communication equipments should have uninterrupted power supply

with proper battery backup so that in case of total power failure, supervisory

control and data acquisition channels do not fail.

In case of existing generating stations or transmission elements without telemetry

facility, the same should be put in place at the earliest. If prolonged operation

without telemetry continues, POSOCO should approach Central Commission.


24/29


23

11) Reduction in Start-up time for GeneratorsAt inter-State level, the entire landscape has changed over past few years. With de-

licensing of generation and provision of open access in Electricity Act, 2003 and

development of organized electricity markets, lot of generation is coming in the

form of merchant generation. Four out of the five regions have been integrated and

formation of National Grid is on the horizon. Under such scenario, there is need

review the Transmission Planning criteria.

12) Strengthening of system study groups in various power sector organizationsThere is need to reinforce system study groups in power sector organisations to

analyse the system behaviour under different network status/ tripping of

lines/outage of generators. Where these do not exist, these should be created.

13) Improved telecom infrastructure for cyber securityFor smoothen operation of grid systems, it is absolutely important that all the

power generating and distributing stations are connected on a very reliable telecom

network.

i) A proper network may be built up preferably using MPLS (Multi ProtocolLevel Switching) which is simple, cost effective and reliable. In remote places

were connectivity is a problem, the stations can use dedicated fibre cable

from the nearest node.

ii) Since POWERGRID has its own fibre optic cables, practically covering allmajor nodes and generating stations, a proper communication/IT network

may be built using dedicated fibres to avoid any cyber attack on the power

system.


D.5 Submission of monthly generation data wrt Renewable Energy SourcesAs per Section 73(i) & (j) of Electricity Act, 2003, OPM Division of CEA has been

entrusted with the task of collecting and recording electricity generation data and

also bring out the reports from time to time. Till date CEA was monitoring all the

existing generating Stations (conventional sources only) with capacity more than

25 MW.


25/29


24

Recent years have shown appreciable growth in Renewable Energy Sources (RES).

As on 31.03.2012 the RES capacity was 24503 MW with a percentage share of

12.26 % wrt the total generating capacity. This is likely to increase to 22.71 % by

31.03.2017. Due to this growth the impact of RES generation on the generation

from conventional energy sources is increasing. Because of above, the contribution

from RES cannot be ignored.

In view of the above, Member (GO&D), CEA had discussed with the representatives

of various SLDCs, POSOCO and RPCs on 28th June, 2012 in CEA to understand

the existing procedure of collection of generation data in respect of Renewable

Energy Sources (RES) and also to expedite the process for regular submission of

monthly information to CEA.

SLDCs are requested to ensure that the complete information in respect of all the

generators covered under RES is furnished to CEA in the Performa at Annexure

D.5.

Shri Ghanshyam Prasad, Director, CEA gave the detail presentation on generation

data management in respect of Renewable Energy Sources; the hand out of

presentation is enclosed at Annexure D.5.1. He further requested that each SLDC

should nominate a nodal officer. The details of nodal officer i.e. Name, Designation,

Contact no., Email ID etc. should be communicated to CEA at the earliest at the

following email/fax.

Fax no.- 011-26107416, 011-26732662

Email : [email protected]. [email protected], [email protected]

with copy to [email protected]

Nodal officers from CEA are :

Shri Ghanshyam Prasad, Director, CEA, 011-26732653 and 26108191,

M-9968301928, and Mrs Sarita Sewak, Dy. Director, 011-26732647.



26/29


25

D.6 Generation Planning (ongoing and planned outages)

The daily availability for hydro stations as given in the meeting is given below.

Khandong 0.708 MU

Kopilli 3.552 MU

Ranganadi - (subject to inflow)Doyang 1.632 MU

Loktak - 2.52 MU

The shutdown proposal approved by the committee is enclosed at Annexure D.6.


D.7 Outage Planning Transmission elementsAfter detail discussion the sub-committee approved the shutdown proposal for Sep

/Oct, 2012 as given in Annexure D.7.

SE (O), NERPC stated that the shutdown proposals of inter regional links should

be planned one month in advance to co-ordinate with the other region as the OCC

meetings of other regions are held on different dates.


D.8 Estimated Transmission Availability Certificate (TAC) for the month ofAugust, 2012.

The Estimated Transmission/System Availability for the month of August, 2012

furnished by PGCIL is 99.9101% as per details at Annexure D. 8. NER

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

September, 2012 so that Final TAC for the month of August, 2012 can be issued.


D.9 Major grid disturbances in the previous month (August, 2012 )As intimated by NERLDC, there was no major grid disturbance during the month

of August, 2012.



27/29


26

D.10 Agenda items by NERLDC1) Requisition based scheduling: In the aftermath of the twin major disturbances

recently, deviations from schedules (over drawal/under drawal, under injection/over

injection) have to be discouraged to enhance the system security and also to avoid

any congestion to neighboring region. Hence preparation of schedules based on 15

minutes block requisition is proposed to be implemented/revived in a time bound

manner.

NERLDC informed that NE Region covers typical hilly terrain and the demand

changes due to frequent change in weather conditions. Therefore, requisition based

scheduling will be beneficial to constituents. All constituents agreed to go for

requisition based scheduling.

The Committee agreed to finalize the requisition based scheduling in next OCC

meeting.


2) Commissioning schedule of Pallatana Units: The date of commissioning furnishedearlier for the first unit is already gone; OTPC may please furnish the new

commissioning schedule along with initial level of generation for proper planning of

operation and optimum dispatch.

The issue has been discussed in detailed under Item No. C.8 above.

3) Telemetry/Voice communication for Pallatana: Commissioning of Pallatana unitsare expected shortly. OTPC has to ensure Telemetry/Voice communication with

NERLDC which is still not in position though it was committed by OTPC in various

forums to have the same in position before starting of generation. NERLDC may be

constrained not to give dispatch clearance in absence of Telemetry/Voice

communication as the security of the grid is at stake.

The issue has been discussed in detailed under Item No D.3.3 above.

4) Ensuring FGMO/RGMO, AVR & PSS tuning(wherever available) for operation ofunits: In line with IEGC & other regulations the following aspects may be ensured

while operation of generating units :


28/29


27

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.

All constituents agreed to submit the data.

5) Status of Strengthening of 132 kV Panchgram- Lumshnong- Khleihriat(Me)link: In the earlier OCC meetings, the matter was discussed in connection with

secured grid operation vis a vis outage of parallel links and also for enhanced

evacuation of Pallatana generation. Status of strengthening in both Assam &

Meghalaya portion may please be intimated along with likely completion time.

The issue has been discussed in detailed under Item No. C.8 above.

6) Submission of Periodic data by power utilities of NER: Formats for submission ofperiodic data by NER utilities are now available at NERLDC website (www.nerldc.org;

Downloads > NERLDC Formats). All concerned Utilities of NER are requested to

furnish these data periodically in time.


7) Submission of Machine Data for Dynamic Simulation as per format circulatedearlier( now available at NERLDC website also) required for system study fordesigning Islanding Scheme:The matter of furnishing of Machine Data had beencommunicated to all constituents vide letter nos. NERLDC/SO-II/5892 dtd. 28-12-

11 and NERLDC/SO-II/9958-68 dtd. 26-03-12 and was also raised in 69th OCC

meeting of NER and discussed in subsequent OCC meetings. In the 75th OCC

meeting it was decided that in case actual data is not available, confirmation

regarding not availability of information is to be given and only the type of

equipment (i.e. type of Generator/Exciter/Governor/ PSS) is to be furnished by Sept

2012.


D.11 Date & Venue of next OCC meetingIt is proposed to hold the 78thOCC meeting of NERPC on 5thOctober, 2012 (Friday).

The exact date and venue will be intimated accordingly.

The meeting ended with thanks to the Chair.


29/29


Annexure-I

List of Participants in the 77thOCC meeting held on 13/09/2012

SN Name & Designation Organization Contact No.

1. Sh. Tarik Mize, EE, SLDC Ar. Pradesh 09436059758

2. Sh. N .C. Das, CGM, SLDC Assam 09435559447

3. Sh. P.K. Sarma, DGM, SLDC Assam 09435344083

4. Sh. M.K. Adhikari, DGM, Comml Assam 09864049287

5. Sh. H. K. M. Baruah, DGM Assam 09954709475

6. Sh. J. K. Baishya, AGM, SLDC Assam 09954055295

7. Smt. L. Bhuyan, AGM Assam 09954055295

8. Sh. K. Goswami, AGM (Comml) Assam 09864020019

9. Sh. J.P. Choudhury, AGM, Comml Assam 09864049287

10. Sh. Sanjeev Goswami, OSD to MoP Assam 09864035095

11. Sh. M. Budha C Sharma, EE Manipur 09463060911

12. Sh. F. E. Kharshiing, EE, SLDC Meghalaya 09863066960

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

14. Sh. Lalnunsanga, AE, SLDC Mizoram 09436144651

15. Sh. Kasho Chishi, EE, (Tran) Nagaland 09436005430

16. Sh. S.I. Asangba Tikhir, AE Nagaland 08974363552

17. Sh. M. Debbarma, AGM (C&SO) Tripura 09436120134

18. Sh. Bikram Debbarma, DGM, SO Tripura 09436450501

19. Sh. Debrata Paul, Sr. Mgr. (C&SO) Tripura 09436500244

20. Sh. Nilanjoy Reang, Sr. Mgr

21. Sh. N.R.Paul, DGM NERLDC 09436302723

22. Sh. Anupam Kumar, Engineer. NERLDC 09436335379

23. Sh. H. Talukdar, Manager (OS) NERTS 09436335237

24. Sh. B. K. Chakravarty, DGM (E) NEEPCO 09436309730

25. Sh. B. Goswami, Sr. Mgr. (O&M) NEEPCO 09436163983

26. Sh. Y. Surjamani Singh, Sr. Mgr.(E) NHPC 09436894857

27. Sh. P. Kanungo, DGM (OS) NERTS 09436302823

28. Sh. A.K. Sharma, Manager (OS) NERPS 09436335241

29. Sh. Shree Narayan, DGM (C&M) OTPC 09968194963

30. Sh. Aroop Sarmah, DGM (Comml) OTPC 09436304964

31. Sh. S. Datta, Sr. Mgr OTPC 09436368209

32. Sh. Ghanshyam Prasad, Director CEA 09968301928

33. Sh. A.K. Mishra, Member Secretary I/C NERPC 09402134275

34. Sh. S.K. Ray Mohapatra, SE (Comml) NERPC

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

36 Sh D K Bauri EE NERPC 09863317236

77th occ minutes

Documents