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POWER GRID CORPORATION OF INDIA LTD

POWER GRID CORPORATION OF INDIA LTD. GRID EVENTS AND ISSUES. in 2 nd SRPC MEETING 30 TH OCTOBER 2006 HYDERABAD. SOUTHERN REGIONAL LOAD DESPATCH CENTRE. ISSUES. 13.0 UNREQUISITIONED POWER OF NTPC STATIONS 15.0 COMPUTATION OF TALCHER STPS-II INJECTION

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POWER GRID CORPORATION OF INDIA LTD

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  1. POWER GRID CORPORATION OF INDIA LTD GRID EVENTS AND ISSUES in 2nd SRPC MEETING 30TH OCTOBER 2006 HYDERABAD SOUTHERN REGIONAL LOAD DESPATCH CENTRE

  2. ISSUES 13.0 UNREQUISITIONED POWER OF NTPC STATIONS 15.0COMPUTATION OF TALCHER STPS-II INJECTION 18.0COMPUTATION OF UI EXCHANGES BETWEEN ER-SR 19.0COMPUTATION OF UI, FORMULAE FOR AVAILABILITY & PLF FOR NLC TPS II STATION 20.0UI ACCOUNT FOR THE WEEK 26.06.06 TO 02.07.06 21.0BIFURCATION OF ENERGY TO THE DISCOMS OF ANDHRA PRADESH AND ESCOMS OF KARNATAKA IN THE MONTHLY REA 22.0REACTIVE CHARGES ON HOSUR- YERRANDANAHALLY LINE

  3. COMPUTATION OF UI NLC TPS-II STATION

  4. Method 1 NLC 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

  5. 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

  6. 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

  7. COMPUTATION OF AVAILABILITY & PLF OF NLC TPS-II STATION

  8. Availability of NLC TPS – II Station has been carried out as given below: N Availability = 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

  9. PLF of NLC TPS – II Station has been carried out as given below: N PLF = 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

  10. UI ACCOUNT FOR THE WEEK 26.06.06 TO 02.07.06

  11. Computation of UI Exchanges between ER - SR

  12. 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).

  13. 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.

  14. 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.

  15. 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.

  16. 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).

  17. Annexure -I CASE – 1 UI from Talcher Stage II to ER when SR frequency < ER frequency Base Case: Talcher Stage II UI =0 MW SR Freq = 49.16 Hz UI Rate= Rs.5/ SR Freq = 49.16 Hz UI Rate= Rs.5/ ER Freq = 49.6 Hz UI Rate= Rs.3/ ER Freq = 49.6 Hz UI Rate= Rs.3/ 0 MW UI (from SR to ER) 0 MW UI (from SR to ER) UI (SR to ER) 0 MW UI (SR to ER) 0 MW Talcher Stage I & II I/C Talcher Stage I & II I/C 0 MW ER 50 MW ER Talcher Stage II Gen: 1650 Schd: 1600 Talcher Stage II Gen: 1600 Schd: 1600 SR SR 1600 MW 1600 MW Base Case +Talcher Stage II 50 MW UI (Talcher Stage 2 actual Generation = 1650 MW against Schd. of 1600 MW) • Issues • Considering 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.

  18. UNREQUISITIONED POWER OF NTPC STATIONS

  19. SCHEDULE 1 OF ABT ORDER DATED 04-01-2000 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 of capacity 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. Cont..

  20. FINAL REGULATIONS : TERMS & CONDITIONS OF TARIFF 26th MARCH 2004PARA-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.

  21. BIFURCATION OF ENERGY TO THE DISCOMS OF ANDHRA PRADESH AND ESCOMS OF KARNATAKA IN THE MONTHLY REA • AS PER THE INDIAN ELECTRICITY ACT, 2003 AND THE REVISED IEGC, THE SLDCs ARE RESPONSIBLE FOR KEEPING THE ACCOUNTS OF THE QUANTITY OF ELECTRICITY TRANSMITTED THROUGH THE STATEs GRIDS AND PREPARATION OF INTRASTATE ENERGY ACCOUNTS Indian Electricity Act 2003 : Section 32(2)(c) Indian Electricity Grid Code (IEGC): Clause No.2.6.3 Indian Electricity Grid Code (IEGC): Background Note (Pages 71-73), para 9 SRLDC LETTER DATED 03.05.06 SRLDC LETTER DATED 12.06.06

  22. Functions of State Load Despatch Centres 32. (1) The State Load Despatch Centre shall be the apex body to ensure integrated operation of the power system in a State. (2) The State Load Despatch Centre shall - (a) be responsible for optimum scheduling and despatch of electricity within a State, in accordance with the contracts entered into with the licensees or the generating companies operating in that State; (b) monitor grid operations; (c) keep accounts of the quantity of electricity transmitted through the State grid; (d) exercise supervision and control over the intra-state transmission system; and (e) be responsible for carrying out real time operations for grid control and despatch of electricity within the State through secure and economic operation of the State grid in accordance with the Grid Standards and the State Grid Code.

  23. 2.6 Role of SLDC 2.6.1 As per section 32 of Electricity Act, 2003, the State Load Despatch Centre (SLDC) shall be the apex body to ensure integrated operation of the power system in a State. 2.6.2 SLDC shall exercise supervision and control over the intra-State transmission system. SLDC will be responsible for carrying out real time operations for grid control and despatch of electricity within the State through secure and economic operation of the State grid in accordance with the Grid Standards and the State Grid Code. The SLDC shall comply with the directions of the RLDC. 2.6.3 SLDC shall keep accounts of the quantity of electricity transmitted through the State grid.

  24. As per the provisions of the revised IEGC, para 9 of the Background Note is reproduced below: 1. “The RLDC shall interact and coordinate only with the SLDCs (and the STUs) if necessary on all matters concerning the State, and with no other intra-State entity 2. The SLDCs shall be responsible for all related coordination with the intra-State entities and interacting on their behalf with RLDC. 3. Each State as a whole shall be treated as an entity in the regional grid, and as one entity for the purpose of allocation/shares in ISGS for daily scheduling and dispatch, for accounting of unscheduled interchange and reactive energy. 4. The bifurcation of the State’s total entitlement in ISGS availability for the day, advising the intra-State entities about their respective entitlements and collecting their requisitions, compiling them into State’s total requisition from ISGS etc. shall be carried out by SRLDC. 5. The STU/SLDC shall be responsible for installation of SEMs on the interconnecting points of all intra-State entities who need to have such meters, for organizing the periodic collection of meter readings, preparation of intra-State energy accounts and issuing the UI statements of all the concerned entities.”

  25. Reactive charges on Hossur-Yerrandahally line • Amicably setteled between TNEB,KPTCL

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