1. INDIAN ELECTRICITY GRID CODE AND OPERATION ISSUES SRLDC/Comml/IEGC/1 P. Bhaskar Rao, DGM (Commercial & C &M), SRLDC,Bangalore

2. INTRODUCTION The Indian Electricity Grid Code (IEGC) lays down the rules, guidelines and standards to be followed by the various agencies and participants in the system to plan, develop, maintain and operate the power system, in the most efficient,reliable and economic manner, while facilitating healthy competition in the generation and supply of Electricity. SRLDC/Comml/IEGC/2

3. Major Milestone in Development of the IEGC 1)CERC advised to prepare a draft of the IEGC on 31.03.99 2)First draft was submitted to CERC by POWERGRID on 9.04.99distributed to all SEBs on 28.04.99 and put out for public comments in April '99 3) First hearing was held by CERC during July '99 4)Revised IEGC draft was submitted by POWERGRID to CERC on 30.08.99 5)CERC issued an order on 30.10.99 followed by another order dated. 22.11.99 6)POWERGRID submitted final IEGC to CERC on 07.12.99 7) Final direction of CERC on IEGC was issued on 21.12.99. 8)POWERGRID has finalised and issued the IEGC by its capacity as CTU on 31.12.99. 9) Date of commencement of the IEGC has been specified as 1.2.2000. SRLDC/Comml/IEGC/3

4. SRLDC/Comml/IEGC Major Milestone in Development of the IEGC Contd… 10)With Modifications,revised IEGC issued on 22 nd March 2002. 11)The New Revised IEGC is effective from 01-04-2006 SRLDC/Comml/IEGC/3

5. OBJECTIVE To bring together a single set of technical rules, encompassing all the utilities connected to/or using the inter-State transmission systems (ISTS) and provides the following:-  Documentation of the principles and procedures which define the relationship between various Users of the inter-State transmission system (ISTS), as well as the RLDC & SLDCs.  Facilitation of the operation, maintenance, development and planning of economic and reliable Regional Grid.  Facilitation for beneficial trading of electricity by defining a common basis of operation of the ISTS, applicable to all the Users of the ISTS. SRLDC/Comml/IEGC/4

6. Non -compliance of IEGC Regional Constituents/ISGS/CTU /RLDC to report matter to MS, RPC MS, RPC to verify and take up with defaulting agency In case of inadequate response MS, RPC to report to CERC CERC may issue order defaulting constituent for compliance In case of failure of compliance, CERC may take appropriate action RPC shall maintain appropriate records of such violations SRLDC/Comml/IEGC/5

7. Structure of the IEGC 1) General 2) Role of RLDC,RPC,CTU, CEA, SLDCs and STUs etc. and their organisational linkages. 3) Planning Code for inter-State transmission system 4) Connection Conditions a) Procedure for connection to the ISTS b) Site responsibility schedule SRLDC/Comml/IEGC/6

8. 5) Operating Code for Regional Grids a) Operating policy b) System security aspects c) Demand estimation for operational purposes d) Demand Management e) Periodic Reports f) Operational liaison g) Outage Planning h) Recovery procedures i) Event information 6) Scheduling & Despatch Code 7) Inter –Regional Exchanges 8) Management of IEGC. SRLDC/Comml/IEGC/7

9. IEGC TO OPERATE ON THE PERIPHERY INTER-STATE SYSTEM X SEB/STU SLDC STATE GOVT. SERC CENTRAL GOVT. CEA CERC RPC CTU RLDC X=  L -  G INTRA-STATE SYSTEM LOAD SRLDC/Comml/IEGC/8 G G LL

10. CHAPTER-2 ROLE OF RLDC, REB, CTU ETC. & THEIR ORGANISATIONAL LINKAGES Regional Power Committee (RPC) RPCs have been constituted by resolutions dated 25.5.2005 of Central Government for the specified Region(s) for facilitating the integrated operation of the power system in the Region. The Secretariat of the Board is headed by the Member Secretary who is appointed by the CEA, together with the other staff for the RPC Secretariat. Under section 29(4) of the Electricity Act,2003, the Regional Power Committee in the region may, from time to time, agree on matters concerning the stability and smooth operation of the integrated grid and economy and efficiency in the operation of the power system in that region. SRLDC/Comml/IEGC/9

11. SRLDC/Comml/IEGC CHAPTER-2 ROLE OF RLDC, REB, CTU ETC. & THEIR ORGANISATIONAL LINKAGES Regional Power Committee (RPC) Functions: To undertake Regional Level operation analysis for improving grid performance. To facilitate inter-state/inter-regional transfer of power. To facilitate all functions of planning relating to inter-state/ intrastate transmission system with CTU/STU. To coordinate planning of maintenance of generating machines on annual basis and also to undertake review of maintenance programme on monthly basis. SRLDC/Comml/IEGC/9

12. SRLDC/Comml/IEGC CHAPTER-2 ROLE OF RLDC, REB, CTU ETC. & THEIR ORGANISATIONAL LINKAGES Regional Power Committee (RPC) Functions: To undertake planning of outage of transmission system on monthly basis. To undertake operational planning studies including protection studies for stable operation of the grid. To undertake planning for maintaining proper voltages through review of reactive compensation requirement through system study committee and monitoring of installed capacitors. To evolve consensus on all issues relating to economy and efficiency in the operation of power system in the region. SRLDC/Comml/IEGC/9

13. Regional Load Despatch Centre (RLDC) The centre so designated for a specified region where the operation of the power system in that region and the integration of the power system with other Regions and areas (within the territory of India or outside) are co-coordinated. Functions The Regional Load Despatch Centre shall be the apex body to ensure integrated operation of the power system in the concerned region. The RLDC shall comply with such principles, guidelines and methodologies in respect of wheeling and optimum scheduling and despatch of electricity as may be specified in the Grid Code. SRLDC/Comml/IEGC/10

14. SRLDC/Comml/IEGC Regional Load Despatch Centre (RLDC) The Regional Load Despatch Centre shall- be responsible for optimum scheduling and despatch monitor grid operations; keep accounts of quantity of electricity transmitted through the regional grid; exercise supervision and control over the Inter-State transmission system ; and be responsible for carrying out real time operations for grid control and despatch of electricity within the region through secure and economic operation of the regional grid in accordance with the Grid Standards and the Grid Code. SRLDC/Comml/IEGC/10

15. SRLDC/Comml/IEGC Regional Load Despatch Centre (RLDC) The RLDC may supervise and control as may be required for ensuring stability of grid operations and for achieving the maximum economy and efficiency in the operation of the power system in the region under its control. All Utilities connected with the operation of the power system shall comply with the directions issued by the RLDC. All directions issued by the RLDCs to any transmission licensee of State transmission lines or any other licensee of the State or generating company (other than those connected to inter-State transmission system) or substation in the State shall be issued through the SLDC and the SLDCs shall ensure that such directions are duly complied with by the licensee or generating company or sub-station. If any dispute arises with reference to the quality of electricity or safe, secure and integrated operation of the regional grid or in relation to any direction given by the RLDC, it shall be referred to Central Commission for decision. SRLDC/Comml/IEGC/10

16. SRLDC/Comml/IEGC Regional Load Despatch Centre (RLDC) However, pending the decision of the Central Commission, the directions of the RLDC shall be complied with by the StLDC or the licensee or the generating company, as the case may be. The following are contemplated as exclusive functions of RLDCs System operation and control including inter-state / interregional transfer of power, covering contingency analysis and operational planning on real time basis; Scheduling / re-scheduling of generation; System restoration following grid disturbances; Metering and data collection; Compiling and furnishing data pertaining to system operation; SRLDC/Comml/IEGC/10

17. SRLDC/Comml/IEGC Regional Load Despatch Centre (RLDC) In case of Open access in Inter-state Transmission, the RLDC of the region where point of drawal of electricity is situate, shall be the nodal agency for the short-term transmission access. The procedure and modalities in regard to short-term Open Access shall be as per the Central Electricity Regulatory Commission (Open Access in Inter-state Transmission) Regulations, 2004, as amended from time to time. SRLDC/Comml/IEGC/10

18. SRLDC/Comml/IEGC CENTRAL ELECTRICITY AUTHORITY (CEA) According to the section 73 of Electricity Act, 2003, the functions of CEA CEA shall formulate short-term and perspective plans for development of the electricity system and co-ordinate the activities of the planing agencies for the optimal utilization ofresources to subserve the interests of the national economy and to provide reliable and affordable electricity for all consumers. to specify the technical standards for construction of electrical plants, electric lines and connectivity to the grid ; to specify the safety requirements for construction, operation and maintenance of electrical plants and electric lines; to specify the Grid Standards for operation and maintenance of transmission lines; to specify the conditions for installation of meters for transmission and supply of electricity. to promote and assist in the timely completion of schemes and projects for improving and augmenting the electricity system; SRLDC/Comml/IEGC/12

19. SRLDC/Comml/IEGC CENTRAL ELECTRICITY AUTHORITY (CEA) According to the section 73 of Electricity Act, 2003, the functions of CEA to collect and record the data concerning the generation, transmission, trading, distribution and utilisation of electricity and carry out studies relating to cost, efficiency, competitiveness and such like matters; to carry out, or cause to be carried out, any investigation for the purposes of generating or transmitting or distributing electricity. CEA shall prepare a National Electricity Plan in accordance with the National Electricity Policy prepared by the Central Government under the provisions of section 3(1) of Electricity Act, 2003. The CEA shall notify the National Electricity Plan once in five years. SRLDC/Comml/IEGC/12

20. State Load Despatch Centre (SLDC) 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. 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. SLDC shall keep accounts of the quantity of electricity transmitted through the State grid. SRLDC/Comml/IEGC/12

21. Central Transmission Utility (CTU) As per the section 38 of Electricity Act, 2003, the functions of the Central Transmission Utility (CTU) shall be – to undertake transmission of energy through ISTS to discharge all functions of planning & co-ordination relating to ISTS with (i) State Transmission Utilities (ii) Central Government (iii) State Governments. (iv) Generating Companies (v) Regional Electricity Boards (vi) Authority (vii) Licensees (viii) Transmission Licensees (ix) Any other person notified by Central Govt. in this behalf. The CTU shall exercise supervision and control over the ISTS SRLDC/Comml/IEGC/13

22. SRLDC/Comml/IEGC Central Transmission Utility (CTU) to ensure development of an efficient, co-ordinated and economical system of inter-State transmission lines for smooth flow of electricity from generating stations to the load centres; to provide non-discriminatory open access to its transmission system for use by- any licensee or generating company on payment of the transmission charges; or any consumer and when such open access is provided by the State Commission under sub-section (2) of section 42 of the Act, on payment of the transmission charges and a surcharge thereon, as may be specified by the Central Commission. SRLDC/Comml/IEGC/14

23. Central Transmission Utility (CTU) Until a Government company or authority or corporation is notified by the Central Government, the Central Transmission Utility shall operate the Regional Load Despatch Centre. CTU shall not engage in the business of generation of electricity or trading in electricity. In case of Open access in Inter-state Transmission, the nodal agency for the long-term transmission access shall be the Central Transmission Utility if its system is used. The procedure and modalities in regard to long-term Open Access shall be as per the Central Electricity Regulatory Commission (Open Access in Inter- state Transmission) Regulations, 2004, as amended from time to time. SRLDC/Comml/IEGC/14

24. Electricity Regulatory Commission Act 1998 sub-section 55(3) The Regional Load Despatch Centre may give such directions and exercise such supervision and control as may be required for ensuring integrated grid operations and for achieving the maximum economy and efficiency in the operation of the power system in the region under its control. Electricity Regulatory Commission Act 1998 sub-section 55(4) Subject to the provisions of sub-section (3), the State Load Despatch Centre in a State may give such directions and exercise such supervision and control as may be required for ensuring the integrated grid operations and for achieving the maximum economy and efficiency in the operation of the power system in that State. SRLDC/Comml/IEGC/15

25. C HAP T E R - 3 PLANNING CODE CTU to discharge all functions of planning and co-ordination related to ISTS in co- ordination with CEA and other related organisations. STU to discharge all functions of planning and co-ordination related to Intra-State TS in co-ordination with related organisations. Planning Policy CEA to develop perspective transmission plan for long term (10-15 years) for ISTS and Intra-State TS (updated continuously of the revisions in load projections and generation scenarios). CTU to carry out the annual planning process for 5- 1 year forward term for identifying major ISTS (incl. Inter-Regional TS) which shall fit in with the long-term plan, perspective plans of CEA.. To consider while planning =>Long term perspective plan of CEA => EPS report of CEA => Transmission Planning Criteria and guidelines by CEA SRLDC/Comml/IEGC/16

26. =>Reports on National Power Policy, Hydro Power Policy etc. issued by GoI relevant for development of ISTS. CTU to plan system strengthening schemes in consultation with CEA. CTU to issue transmission plan each year by 30th Sep. for next 5 year Transmission Plan (Prepared by CTU) includes. => Transformers, Reactors, Capacitors, SVCs FACTS => lSTS schemes open to private investors => Action taken to fulfil additional requirement => Actual progress made on new schemes STU to prepare plans based on CTU's plans Standing Committee to coordinate plans of STU/CTU. SRLDC/Comml/IEGC/17

27. Planning Criterion. CEA's Transmission Planning Criterion.. Loss of most severe single system in feed without loss of stability. Anyone of the above events not to cause Loss of supply; Prolonged operation of the high/low system frequency/voltage; System instability;. Unacceptable overloading of ISTS elements. Implementation of Transmission Plan. CTU to determine actual programme of implementation of transmission plan and to ensure completion in required time frame. SRLDC/Comml/IEGC/18

28. C H A P T E R - 4 CONNECTION CONDITIONS What's Connection Conditions? Minimum technical and design criteria to be complied with ISTS not to impose unacceptable effects on the connected agency Clearly specify responsibility for each equipment at each connection Treat all parties non-discriminatory Applies to all constituents connected to ISTS including embedded units (within State) connected to ISTS Procedures. Agency to submit application (standard format) to CTU stating Purpose,. Connection point,. description of apparatus; Beneficiaries of proposed connection; Construction, schedule & target completion date; Confirmation of compliance with IEGC. SRLDC/Comml/IEGC/19

29. CTU to make formal offer (within 1 month) to Agency setting out Requirements; Procedures; Connection Agreement On compliance by agency; CTU to notify the agency to connect For Existing connections: To sign Connection Agreements within 1 year (in case of delays in signing of CA, constituent may file petition with CERC along with recommendations/comments of CTU) Contents of Connection Agreement Details of connection; technical requirement; Commercial Arrangements; Capital expenditure; Site Responsibility Schedule; Philosophy of protection & I relay settings Generating Units shall have AVR, protective & safety devices shall have turbine speed governor of droop characteristics 3-6% shall be capable of increasing output to 105% of MCR for at least 5 minutes. SRLDC/Comml/IEGC/20

30. Reactive Power Compensation Agency to provide Reactive power compensation as per requirement indicated by CTU in Connection Agreement. Connection Agreement Site Responsibility Schedules; Single Line Diagrams; ; Site Common Drawings; Procedure for Site Access; Site operational activities and Maintenance Schedule of assets of Regional Grid - CTU to finalize by 30th Sep, each year. SRLDC/Comml/IEGC/21

31. CHAPTER-6 OPERATING CODE Operating Procedures - To be developed by CTU in consultation with constituents System Security Aspects: No opening of lines without RLDC‘s instructions/advice/consent except.(i) in emergency, (ii) to avoid serious damage to a costly equipment. Complete synchronization of grid shall be restored as soon as the conditions again permit it. List of such important elements to be prepared by RLDC in consultation with constituents. Generating Units* All units to have free governor operation with droop of 3% - 6%. No suppression or deliberate dead bands/time delays. Units to pick up by 5% (up to 105% of MCR) instantaneously for at least five (5) minutes or within technical limits prescribed by the manufacturer when frequency falls due to a system contingency. Non-capability to be permitted by RLDC. SRLDC/Comml/IEGC/22

32. .Recommended rate for changing the governor setting (supplementary control) : 1% per minute and faster, at freq. <49.5 Hz..No sudden reduction of generation or increase in load by more than 100 MW without prior intimation to/consent of the RLDC, particularly when frequency is falling or is below 49.0 Hz.).All units to have AVRs in operation (with appropriate settings). Non-operation only by consent of RLDC. CTU to carry out tuning of Power System Stabilizers (PSS) in AVRs and maintain appropriate records. Protection Relay Settings To be co-coordinated periodically by PCC of REB. Operating Frequency Range 49.0- 50.5 Hz. Band SRLDC/Comml/IEGC/23

33. Operating Voltage Standards Range ( in kV) NormalMaximumMinimum 400420360 220245200 132145120 *For thermal units >200 MW and Reservoir-based hydro units >50MW,the clauses will become effective along with ABT implementation and for all other units 3 months thereafter. All nuclear units exempted up to next review of IEGC. Voltage Standards Statutory Limits as per Section 54 of IE Rules, 1956 Limits under IE Rules Low VoltageVoltage <250 V ± 6% Medium Voltage650 V > Voltage >250 ± 6% High Voltage33 KV >Voltage >650 V ± 6% to –9% Extra-High VoltageVoltage > 33 KV+ 10% to –12.5% SRLDC/Comml/IEGC/24

34. As per IEGC EHV Voltage MaximumMinimum IEGCIE Rules +10%IEGCIE Rules (- 12.5%) 400 kV420(+5%)440360350 220 kV245(+10%)245200193 132 kV145(+10%_145120115 SRLDC/Comml/IEGC/25

35. Frequency Standards Frequency Band for safe operation of Steam Turbines and adopted in IEGC 49 -50.5 Hz. ± 3% Statutory Limits as per section 55 of IE Rules, 1956 IE Rules, 1956 55, Declared frequency of supply to consumer: Except with the written consent of the consumer or with the previous sanction of the State Government a supplier shall not permit the frequency of an AC supply to vary from the declared frequency by more than 3%. 50 Hz. 48.5 Hz. 49 Hz. 51 Hz. 51.5 Hz. SRLDC/Comml/IEGC/26

36. Under Frequency Load Shedding Scheme to be finalized in REB forum REB to ensure its effective application. With prior consent of RLDC can be kept out of service temporarily in case of extreme exigencies. REB to periodically check and keep records of its findings. Demand Estimation - by SLDCs to forecast demand Demand Control - by SLDCs SLDCs to restrict net drawal schedules at Freq. <49.5 Hz. Manual Load Shedding =>When Freq. <49 Hz. =>During System contingencies (on RLDC's instructions) SRLDC/Comml/IEGC/27

37. Periodic Reports: A weekly report shall be issued by RLDC to all constituents of the Region and REB Secretariat and shall cover the performance of the Regional grid for the previous week viz. a) Frequency profile Maximum and minimum frequency recorded daily and daily frequency variation index (FVI). b) Voltage profile The voltage profile of selected substations. c) Major Generation and Transmission Outages. d) Transmission Constraints e) Instances of persistent/significant non-compliance of IEGC. SRLDC/Comml/IEGC/28

38. Outage Planning By REB Secretariat Outage Planning Process Real Time Outage Process. Constituent to obtain final approval in real time from RLDC before availing an outage.RLDC to check/conduct studies for contingencies and can defer outage in case of Major grid disturbance (Total black out in Region); System isolation; Black out in a constituent State; Any other event in the system that may have an adverse impact on the system security by the proposed outage. 30th Nov.SEBs/STUs/CTU/ISGS to give proposed annual outage plan to REB Sectt. 31st Dec.REB Sectt. To issue Draft annual Outage Plan 31st Jan.REB Sectt. To issue Final annual Outage Plan. Quarterly & Monthly Review of Final Annual Outage Plan by REB Sectt. SRLDC/Comml/IEGC/29

39. Recovery Procedures For Region to be developed/updated annually by RLDC in consultation with constituents /REB Secretariat For constituents to be developed by themselves in coordination with RLDC and updated every year. Event Information ! All to send information/data of DR/SER etc., to RLDC/REB Secretariat for analysis; No blocking of any information/data required by RLDC. SRLDC/Comml/IEGC/30

40. Reportable events Any of the following events require reporting by RLDC/Regional constituent 1) Violation of security standards 2) Grid indiscipline 3) Non-compliance of RLDC's instructions 4) System islanding/system split 5) Region blackout/partial system blackout 6) Protection failure on any element of ISTS, and on any item on the 'agreed list' of the intra-State system 7) Power system instability 8) Tripping of any element of the Regional grid SRLDC/Comml/IEGC/31

41. Details of the event 1) Time and date of event 2) Location 3) Plant and/or Equipment directly involved 4) Description and cause of event 5) Antecedent conditions 6) Demand and/ or Generation (in MW) interrupted and duration of interruption 7) All Relevant system data including copies of records of all recording instruments including Disturbance Recorder, Event Logger, DAS etc. 8) Sequence of tripping with time 9) Details of relay flags 10) Remedial measures SRLDC/Comml/IEGC/32

42. C H A P T E R - 7 SCHEDULING & DESPATCHING CODE Demarcation of Responsibilities. Each Region is a loose power pool and each state is a notional Control Area. (Decentralized Scheduling and Dispatch). RLDC can direct SLDCs/ISGSs in case of system contingencies, to change drawal/injection and if time permits, RLDC will ascertain whether situation has arisen due to => Deviations from schedule => Bilateral Exchange These can be terminated by RLDC.. All joint/bilateral agreements to be filed with RLDC/REB Secretariat.SEMs to be installed by CTU at all interconnection points for recording Actual Interchanges and MVARh drawals.. Regional Energy Accounting to be done by REB Sectt.based on metered and processed data (Actual net injection of ISGS and actual net drawal of each beneficiary) received from RLDC. SRLDC/Comml/IEGC/33

43. Settlement Systems*. Accounting on weekly basis. Capacity and Energy Charges billing on monthly basis Billing of adjustments for deviations on weekly basis RLDC to furnish data to REB Secretariat by Thursday noon for week ending Sunday. REB Secretariat to finalize and issue REA by Tuesday, for seven day period ending on penultimate Sunday. All data to be retained for 20 days (for RLDC & REB) for verification. Commercial Mechanism * Availability Based Tariff ( a) Capacity Charge (b) Energy Charge (c) Adjustment for Deviations SRLDC/Comml/IEGC/34

44. c) Adjustment for Deviations =(Actual energy interchange in a 15 min. Time block - scheduled interchange for the time block) x Frequency linked UI price. TQTAL PAYMENT FOR THE DAY = (a) + (b)± (c)  Unfair gaming/collusion to be reviewed by RLDC and reported to MS, SREB. a) Capacity Charge = Before-the-fact ex-pp MW Capability for the day x Capacity charges rate x SEB's % share b) Energy charges =Before-the-fact MWh for the day as per ex-bus drawal schedule for the SEB x Energy charge rate. SRLDC/Comml/IEGC/35

45. 1000 800 600 400 200 0 06121824 Forecast ex-bus capability of power plant SEB - A’s entitlement (40%) SRLDC/Comml/IEGC/36 MW -----  TIME in HOURS ---- 

46. SETTLEMENT SYSTEM For the day: 0000 hrs. to 2400 hrs. Central Generating Stations 1 23 Ex-Bus Capability x1x2x3 (Forecast) __________ SEB-A’s sharea1a2a3 SEB-B’s shareb1b2b3 SEB-C’s sharec1c2c3 For a particular 15 minute time block SEB-A’s requisition a’1a’2a’3 SEB-B’s requisition b’1b’2b’3 SEB-C’s requisition c’1c’2c’3 _________ CGS’s schedule x1’x2’x3’ MW SRLDC/Comml/IEGC/37

47. SETTLEMENT SYSTEM Total capacity charge payable to CGS-1 for the day = x1 * capacity charge rate of CGS-1 Total Energy charge payable to CGS-1 for the day = x 1 ’ * Energy charge rate of CGS-1 4 Total capacity charge payable by SEB-A for the day = a 1 * capacity charge rate of CGS-1 + a 2 * -do- CGS-2 + a 3 * -do- CGS-3 Total Energy charge payable by SEB-A for the day = (a 1 ’) * Energy charge rate of CGS-1 ( 4 ) + (a 2 ’) * -do- CGS-2 ( 4 ) + (a 3 ’) * -do- CGS-3 ( 4 ) All capacity charge and Energy charge payments to be made by SEBs directly to CGS. SRLDC/Comml/IEGC/38

48. SETTLEMENT SYSTEM Actual (metered) injection of CGS-1 in the time block = X 1 MWh. Excess injection = (X1 – x 1 ’ ) MWh. 4 Amount payable to CGS-1 for this =(X1-x1’) * pool price for the block. 4 SEB-A’s scheduled drawl for time block = a 1 ’+a 2 ’+a 3 ’ = a’ MW (ex-CGS Bus) SEB-A’s NET drawal schedule = (a’ – Notional Transm. Loss) MW = (a’ – Notional Transm. Loss) = A’ MWH 4 Actual (metered) net drawal of SEB-A during time block = A MWH Excess drawal by SEB-A = (A-A’) MWh. Amount payable by SEB-A for this = (A-A’) * pool price for the block. All above payments for deviations from schedules to be routed through a pool A/C SRLDC/Comml/IEGC/39

49. 49.049.850.249.4 50.6 Hz Incremental Cost (Paise/kWH) UI Price System Frequency Station Generation 75 % 25 % 0 % 50 % 420 280 140 0 100 % Pool Price MANUAL LOAD-SHEDDING DIESEL GENR, DEPLETED HYDRO GAS - TURBINE NORMAL HYDRO LOAD-CENTER COMBINED CYCLE PIT - HEAD NUCLEAR OVER FLOWING HYDRO Typical Graph Depicting Pricing of Unscheduled Interchanges w.r.t. System Frequency SRLDC/Comml/IEGC/40

50. Scheduling Process On Day-l 10 AMISGSs advise foreseen plant-wise ex-. power plant MW, MWh * capability for next day 11 AMRLDC advises SEBs their MW, MWh* shares in foreseen ISGSs' availability 3 PMSLDCs furnish their,time-wise MW requisition from the above, and schedule of bilateral exchanges, if any 5 PMRLDC issues' despatch schedules' for ISGSs and 'net drawal schedules' for SEBs, for each hour the next day starting at midnight 10 PMSLDCs may inform any change of the above or bilateral exchanges to RLDC, if required by any new development during the day 11 PMSchedules frozen for the next day. RLDC Issues final drawal schedules to each State & Despatch schedule to each ISGS SRLDC/Comml/IEGC/41

51. On Day 0 On Day + 1. RLDC to issue before-the- fact Capacity Declaration/Schedules finally implemented by RLDC (Datum for accounting and working out average ex-power plant capability). Time block tAny State may revise drawal schedule from any/all ISGS Any ISGS may revise their foreseen capability Time block t+3RLDC to issue revised ‘drawal schedules' and despatch schedules SRLDC/Comml/IEGC/42

52. Reactive Power Tariff and Voltage Control 1. Constituent to pay for VAR drawal Voltage < 97% VAR injection Voltage > 103% Constituent to receive for VAR injection Voltage < 97% VAR Drawal voltage > 103% 2. The charge/payment for VAR Interchanges. With ISTS : To/from Pool Account. Between two utilities: Between Beneficiaries. With ISGS: To/From utilities. Reactive Power Tariff Up to 31.3.2001 @ 4p/kVARh Thereafter 5% p.a. Escalation (Unless revised by CERC) SRLDC/Comml/IEGC/43

53. MANAGEMENT OF IEGC CTU responsible for management of IEGC.. IEGC Review Panel to consider proposals for modifications and recommend to CERC for approval. Constitution of Review Panel =>CERC to constitute based on the recommendations of the heads of the listed organisations/bodies. => Representative( s) from each of following: One each from NTPC, NHPC, NPC, PTC & CEA 5 Two from each REB representing Constituents of the Region 10 One from MPPs 1 One from Railways/Steel/Coal 1 One from CII/FICCI/ ASSOCHAM 1 One from CERC (as an observer) 1 D(0), POWERGRID Chairman/Convenor SRLDC/Comml/IEGC/44

54. Working of Review Panel Constituent/ISTS user to send written request to CTU CTU to examine the proposed change/interpretation and circulate to all panel members along with its comments. CTU to compile comments and send to all the members for their response =>Consensus : CTU to submit for approval of CERC => No consensus: CTU may convene meeting of Review Panel CTU to finalise its recommendation and submit to the CERC. Rules and guidelines to be followed by the Review Panel shall be as approved by CERC on 17.11.2000. SRLDC/Comml/IEGC/45

55. Functions of Review Panel => To keep ‘IEGC working’ under scrutiny => To consider requests for amendments => To issue guidance on the interpretation and implementation' of the IEGC => To examine problems raised by the Users. CTU to hold sub- meetings with User(s) to prepare proposals for the panel meeting/decision. => Constituents' representative responsible to interact with all concerned in their Regions, i.e. The State Government, the SERCs, SEBs/STUs, all generating companies, the distribution companies, all licensees etc., as necessary for discharging their role as the Constituents' representatives on the IEGC Review Panel. SRLDC/Comml/IEGC/46

56. SRLDC/Comml/IEGC/47