POWER GRID CORPORATION OF INDIA LTD

SOUTHERN REGIONAL LOAD DESPATCH CENTRE

in

2nd SRPC MEETING

30TH OCTOBER 2006

HYDERABAD

GRID EVENTS AND ISSUES

ISSUES

6.1 400 KV KAIGA – GUTTUR

6.2 400 KV MADURAI – TRIVENDRUM D/C LINE

7.0 TALCHER – KOLAR HVDC

9.0 400 KV KAIGA – NARENDRA D/C LINE

10.0 EVACUATION SCHEMES FOR NEW CENTRAL

SECTOR GENERATING STATIONS

12.0 UNREQUISITIONED POWER OF NTPC

STATIONS

11.0 KALPAKKAM – EVACUATION SCHEME

ISSUES (Continued …)

14.0 TALCHER – KOLAR INTERTRIP SCHEME

16.0 ALTERNATE PATH FOR EVACUATION OF

TALCHER STAGE 2 POWER

17.0 INTER REGIONAL TRANSMISSION LINKS

BETWEEN ER/WR AND SR

18.4 HIGH VOLTAGE CONDITIONS

KAIGA – GUTTUR TRIPPING DETAILS

18.2 HIGH FREQUENCY CONDITIONS

STOA – CHIKKODI – KOLHAPUR LINE

1st meeting of TC of SRPCon 30th Oct 2006

MVAR absorption at Sharavaty• As per the requirement of grid, generators to generate/absorb

reactive power.• Cannot agree for objections of KPCL• GT taps could be different for units• Sharing of reactive power could be different• Depending on seasons taps could be specified through system

studies• As long as reactive generation/absorption is within capability curves

there should not be any problem• Generators should vary excitation between plus or minus 5% GT

terminal voltage/or limits as specified by manufacturers• KPCL should cooperate with SLDC in maintaning voltages

Computation of Talcher STPS II Injection

• Revised IEGC –w.e.f. 01-04-2006• Specific chapter on Inter –Regional exchanges• Detailed paragraph on scheduling ,operation of Talcher II

-net injection of Talcher II

Commercial meeting MOM:• NTPC s made the request purely on technical merits

without any commercial considerations• Any philosophy would be acceptable to hem• Acceptable for prospective revisions ,if any

Computation of UI exchanges between SR-ER

• DETAILS TO BE GIVEN BY srinivas

• Our letter details to be incorporated

Computation of UI formulae for availability plf,for NLC station

• SRPCs agenda to be copied

COMPUTATION OF UI NLC TPS-II STATION

Method 1NLC TS-II stage-1&2 : • Mines Allocation from Stage -1 : 7.94 %• Mines Allocation from Stage -2 : 5.95 %• Net DC of Stage – 1 : A• Net DC of Stage – 2 : B• Anticipated Mines consumption from Stage-1:

A/(100-7.94)*7.94 = M1• Anticipated Mines consumption from Stage-2:

B/(100-5.95)*5.95 = M2• Total Anticipated Mines consumption : M1+M2 = AM• Actual Mines consumption : MC• Actual Ex-Bus Generation of Stage-I : C• Actual Ex-Bus Generation of Stage-2 : D• Net injection of NLC TS-II Stage-1 : C – (MC/AM)*M1• Net injection of NLC TS-II Stage-2 : D – (MC/AM)*M2

Method 2

NLC TS-II stage-1&2 : • Anticipated Mines consumption from Stage-1: M1

• Anticipated Mines consumption from Stage-2: M2

• Total Anticipated Mines consumption : M1+M2 = AM

• Actual Mines consumption : MC

• Actual Ex-Bus Generation of Stage-I : C

• Actual Ex-Bus Generation of Stage-2 : D

• Net injection of NLC TS-II Stage-1 : C – (MC/AM)*M1

• Net injection of NLC TS-II Stage-2 : D – (MC/AM)*M2

Method 3

NLC TS-II stage-1&2 : • Mines Allocation from Stage -1 : 7.94 %• Mines Allocation from Stage -2 : 5.95 %• Actual Ex-Bus Generation of Stage-I : A• Actual Ex-Bus Generation of Stage-2 : B• Anticipated Mines consumption from Stage-1:

(A*7.94/100) = M1• Anticipated Mines consumption from Stage-2:

(B*5.95/100) = M2• Total Anticipated Mines consumption : M1+M2 = AM• Actual Mines consumption : MC• Net injection of NLC TS-II Stage-1 : A – (MC/AM)*M1• Net injection of NLC TS-II Stage-2 : B – (MC/AM)*M2

COMPUTATION OF AVAILABILITY & PLF OF

NLC TPS-II STATION

Availability of NLC TPS – II Station has been carried out as given below:

NAvailability = 1000000 x DCi / { Nx IC x (100 – AUXn)(100-MINent)}%

i = 1

DCi = Average declared capacity for the ith day of the period in MW

N = Number of days during the period,

IC = Installed capacity of the generating station in MW

AUXn = Normative auxiliary consumption

MINent = Percentage allocation of mines in the generating station specified

by GOI

PLF of NLC TPS – II Station has been carried out as given below:

NPLF = 1000000 x SGi / { Nx IC x (100 – AUXn)(100-MINent)}%

i = 1

SGi = Average Scheduled Generation for the ith time block in MW

N = Number of days during the period,

IC = Installed capacity of the generating station in MW

AUXn = Normative auxiliary consumption

MINent = Percentage allocation of mines in the generating station

specified by GOI

UI ACCOUNT FOR THE WEEK

26.06.06 TO 02.07.06

Annex- IDUE DATE FOR PAYMENTS 18-07-06

A. ABSTRACT OF UNSCHEDULED INTERCHANGES B. ABSTRACT OF UNSCHEDULED INTERCHANGES (Restricting

to the lesser of the two as per the 126th SREB decision)

UTILITIES

RECEIVABLE IN TO THE POOL

(RECEIVE-IN)

PAYABLE OUT OF THE POOL

(PAY-OUT) UTILITIES

RECEIVABLE IN TO THE POOL

(RECEIVE-IN)

PAYABLE OUT OF THE POOL

(PAY-OUT)

RSTPS STAGE I & II 83.96583 RSTPS STAGE I & II 83.96583

RSTPS STAGE III 0.69477 RSTPS STAGE III 0.69477

TALCHER STAGE 2 42.96052 TALCHER STAGE 2 42.96052

NLC II STAGE 1 5.66564 NLC II STAGE 1 5.66564

NLC II STAGE 2 8.89877 NLC II STAGE 2 8.89877

NLC TPS1 EXPANSION 5.46687 NLC TPS1 EXPANSION 5.46687

APTRANSCO 131.15601 APTRANSCO -80.80883

KPTCL 33.94428 KPTCL -20.91401

KSEB 7.12195 KSEB 7.12195

TNEB 23.82476 TNEB -14.67909

PONDYCHERRY 63.37897 PONDYCHERRY 63.37897

GOA 14.43907 GOA 14.43907

PG HVDC 9.49517 PG HVDC 9.49517

ER 183.16909 ER 183.16909

WR 175.32040 WR 175.32040

TOTAL 547.41454 242.08756 TOTAL 242.08756 242.08756

* Surplus of 1,16.40,193 is retained in the SR Pool. The same will be discussedand finalised in the forth coming commercial committee meeting of SRPC.C. DETAILS OF TIME-BLOCKS OF GRID DISTURBANCE AND UI SUSPENSION : NILD. DETAILS OF TIME BLOCKS WHEN SCHEDULES DEEMED TO HAVE BEEN REVISED EQUAL TO ACTUALS DUE TO TRANSMISSION CONSTRAINTS :

DATE TIME-BLOCKS CONSTITUENTNIL

Estimated Loss Percentage : 4.41 Actual Loss Percentage : 3.30

SOUTHERN REGIONAL LOAD DESPATCH CENTER

(UI figures in Rs. Lakhs) (UI figures in Rs. Lakhs)

ABT BASED UI ACCOUNT FOR THE WEEk 26-06-2006 TO 02-07-2006

REASON

Computation of UI Exchanges between

ER - SR

The methodology adopted by SRLDC for computation of UI between ER-SR was based on the following stipulations made in IEGC (effective from 1.4.2006):

7.6.1 The regional boundaries for scheduling, metering and UI accounting of inter-regional exchanges between ER & SR shall be as follows:

400 kV Bus couplers between Talcher-I and Talcher-II

400 kV East bus of Gazuwaka HVDC.

7.6.3. No attempt shall be made to split the inter-regional schedules into linkwise schedules (where two regions have two or more interconnections).

As regards to the UI computation of Talcher Stage II, the following provisions as stated in IEGC were also taken into consideration:

7.4.2. For a clear demarcation of responsibilities and minimal to-and-fro coordination, the scheduling of Talcher-II shall be coordinated by SRLDC, and the 400 kV AC bus-couplers between Talcher-I (2x500 MW) and Talcher-II (4x500 MW) shall be treated as the interface between ER and SR.

7.4.6. …… The difference between the actual injection of Talcher II and the dispatch schedule shall constitute the UI of Talcher-II, for which payments shall be made from/into the UI pool account of Southern region operated by SRLDC, but at the UI rate corresponding to ER repeat ER frequency. The energy accounting for Talcher-II STPS shall be carried out by SRLDC.

7.4.7. While the dispatch schedule for Talcher-II shall be as advised by SRLDC, the actual generation at Talcher-II may be varied by station operators depending on ER frequency, as long as the resulting UI does not cause a transmission constraint in ER. In case of a transmission constraint being caused in ER by the UI of Talcher-II, ERLDC may advise Talcher-II to curtail its UI under intimation to SRLDC. Any such advise shall be immediately complied with by Talcher-II.

On going through the above clauses with respect to scheduling and UI computation in respect of Talcher Stage II vis-à-vis exchange and computation of UI between ER & SR, the following points require specific attention:

Any UI exchange between ER & SR on the inter-regional links, viz. Gazuwaka HVDC back-to-back and 400 kV bus coupler between Talcher I and Talcher II is carried out depending on the frequency of both the regions and only with the consent of SRLDC/ERLDC control rooms. This is done in order to ensure that any such UI exchange is giving benefit to the constituents in both the regions and is not resulting into a negative residual in the IRE (Inter-Regional Energy) pool. However, in case of the UI exchange between Talcher II and ER the philosophy is different in the sense that the UI flow between Talcher II and ER though comes in the category of IRE flow, in controlling its direction and quantum SR generally has no role and how much UI would be maintained rests only at the discretion of Talcher II. In order to further elaborate this, it may be pointed out that there could be a situation when SR frequency is lower than ER frequency and UI flow in the direction from SR to ER is not desirable. However, even under such situation in case Talcher II finds that it is beneficial to push power to ER under UI (as long as its variable cost is lower than UI rate prevailing in ER), the station may do so irrespective of the frequency of SR and in case it is clubbed with the SR-ER (IRE) UI, a negative UI amount is generated between SR & ER. This case is illustrated with an example at Annexure-I.

Whenever UI transactions are there between ER & SR, the net gain due to UI transactions (differentials generated in the IRE accounts) is distributed equally between ER & SR constituents. In case the UI of Talcher II with ER is also clubbed with the UI of SR, then the SR constituents do not get their equitable share and stand to lose. This is illustrated with examples at Annexure-II by considering a typical case of UI transaction from SR to ER.

It may therefore be seen that in view of the specific location of Talcher II vis-à-vis other ISGSs, the UI computation in respect of Talcher II is required to be followed in a manner which would be based on the IEGC provisions as stated above and at the same time it would not defeat the basic UI philosophy which stipulates that the UI exchange between two agencies/ regions should benefit both the parties. In order to achieve this, whenever UI transactions are there in respect of Talcher II with ER, the UI calculations have to be carried out as per the IEGC provisions (clause 7.4.6 of IEGC) i.e. at ER frequency. However as per this clause, as the payment for this UI to Talcher II has to be made from the UI pool account operated by SR, it is natural that SR must get the equivalent amount from the ER. Furthermore, as no differential has been generated in SR/ER on this account, there cannot be any sharing of accumulated differential UI and therefore the possible viable approach within the framework of IEGC regulations could be to treat this transaction as a UI only between Talcher II and ER and only while accounting these amounts (as it is) can be reflected in the SR weekly UI account, as elaborated under the case in Annexure-II (Methodology 2).

ERFreq = 49.6 HzUI Rate= Rs.3/

TalcherStage IIGen: 1600Schd: 1600

1600 MWSR

Talcher Stage I & II I/C

SR Freq = 49.16 HzUI Rate= Rs.5/

UI (SR to ER) 0 MW

0 MWER

0 MW UI (from SR to ER)

Annexure -ICASE – 1 UI from Talcher Stage II to ER when SR frequency < ER frequencyBase Case: Talcher Stage II UI =0 MW

Base Case +Talcher Stage II 50 MW UI (Talcher Stage 2 actual Generation = 1650 MW against Schd. of 1600 MW)

ERFreq = 49.6 HzUI Rate= Rs.3/

TalcherStage IIGen: 1650Schd: 1600

1600 MWSR

Talcher Stage I & II I/C

SR Freq = 49.16 HzUI Rate= Rs.5/

UI (SR to ER) 0 MW

50 MWER

0 MW UI (from SR to ER)

IssuesConsidering the variable cost of Talcher Stage II as around 80 paisa it would be beneficial for Talcher Stage II to generate positive UI as the ER UI rate is more than its variable cost.

For every unit of power exported to ER, Talcher Stage II would get a price of Rs 3/Unit.However if the UI by Talcher Stage II to ER is considered as UI from SR to ER, then it would be a case of –ve UI

For every unit of power exported , SR would expect a price of Rs 5/Unit while ER would be able to give a price of Rs 3/Unit only. Such transactions accumulated during that periods could cause commercial implications.

In order to address this issue ,the UI transactions can be considered between Talcher Stage II and ER, however the accounts can be routed through SR.

Para 8 (ii) The beneficiaries will have full freedom for negotiating any

transaction for utilisation of their capacity shares. In such cases, the beneficiary having allocation in the capacity of the generating station will be liable for full payment ofcapacity charges and energy charges (including that for sale of power under the transactions negotiated by them) for all its scheduled and unscheduled transactions from its capacity share.

(iii) If there is any capacity which remains un-requisitioned during day-to-day operation, RLDC, shall advise all beneficiaries in the region and the other RLDCs so that such capacity may be requisitioned through bilateral arrangements with the concerned generating company/beneficiary(ies) under intimation to the RLDC.

SCHEDULE 1 OF ABT ORDER DATED 04-01-2000

Cont..

FINAL REGULATIONS : TERMS & CONDITIONS OF TARIFF 26th MARCH 2004

PARA-30. Billing and Payment of Capacity Charges:(ii) The beneficiaries shall have full freedom for negotiating any

transaction for utilisation of their capacity shares. In such cases, the beneficiary having allocation in the capacity of the generating station shall be liable for full payment of capacity charges and energy charges (including that for sale of power under the transaction negotiated by him) corresponding to his total allocation and schedule respectively.

(iii) If any capacity remains un-requisitioned during day-to-day operation, the Regional Load Despatch Centre shall advise all beneficiaries in the region and the other Regional Load Despatch Centres so that such capacity may be requisitioned through bilateral arrangements either with the concerned generating company or with the concerned beneficiary(ies) under intimation to the Regional Load Despatch Centre.

The information regarding un-requisitioned capacity shall also be made available by the Regional Load Despatch Centres through their respective websites.

Bifurcation of Energy to Discoms

• Responsibility of SLDCs as per clause 2.6.3 of IEGC

• Matter taken up with SLDCs.

• Karnataka SLDC issuing the bifurcation to ESCOMs

• APPCC is doing for AP state discoms

• No-need for RLDCs to do this activity

Reactive charges on Hossur-Yerrandahally line

• Amicably setteled between TNEB,KPTCL