Indian Electricity Grid Code

1. Indian Electricity Grid Code

2. Contents • General • Role of various organisations and their linkages • Planning code for Inter State Transmission • Connection Code • Operating Code • Scheduling and Despatch Code • Miscellaneous

3. 1. General

4. IEGC RulesGuidelinesStandards • Documentation of the principles which define relationship between various users • Facilitation of optimal operation • Facilitation power markets and ancillary services • Facilitation renewable energy sources Power System Introduction for Utilities ISTS To plan, develop, operate & maintain National/Regional Grid connected with / using

5. Compliance Oversight (1.5) CERC RLDC Report Repeated Violation/ Persistent Non Compliance suo-motto Action Consensus RPC Report issues not sorted

6. Compliance Oversight (1.5) CERC Non Compliance by NLDC, RLDC, SLDC, RPC or any other person Report by any person through petition Action 6

7. 2. Role of Various Organizations and their linkages NLDC, RLDC, RPC, CTU, CEA, SLDC & STU

8. NLDC • Economy and Efficiency of National Grid • Monitoring of operations and grid security of National Grid • Restoration of synchronous operation of National Grid • Trans-national exchange of power • Feedback to CEA & CTU for national Grid Planning • Dissemination of information • Levy and collection of fee and charges - CERC • Disse Role of NLDC (2.2) Supervision Coordinate RLDC Supervision & control Coordinate RPC for regional outage Plan Inter Regional Links Accounting

9. RLDC • Real time operation , control & contingency analysis • Generation scheduling/ re-scheduling • Restoration • Metering & data collection • Compiling & furnishing of operation data • Operation of Regional UI pool Account. Reactive energy account and Congestion charge account • Operation of ancillary services Exclusive functions Role of RLDC (2.3)

10. Role of RLDC (2.3) RLDC • Functions • optimum scheduling • and despatch of • electricity • Monitor grid operation • Keep accounts of • electricity transmitted • Exercise Supervision • and control over • the ISTS • Real time operations Apex body for integrated operation Comply the directions Directions SLDC Central State For ST Open Access- Nodal Agency • Licensee • Generating company • Generating station / Sub-stations • any other concerned person 10

11. Decisions RLDC/SLDC/CTU/ STU/ Users Role of RPC (2.4 ) RPC • Facilitate the stable and smooth operations of the system • Functions: • regional level operation analysis • facilitate inter-state/inter-regional transfer of power • facilitate planning of inter-state/intrastate transmission system • coordinate maintenance of generating units • coordinate maintenance of transmission system • protection studies • Planning for maintaining proper voltages • Consensus on issues related to economy and efficiency MS SRPC shall certify Availability of transmission system Prepare Regional Energy Account, Weekly UI, Reactive & Congestion charge account

12. Role of CTU (2.5) CTU Planning shall operate • to undertake transmission of electricity through ISTS • to ensure development of an efficient, co-ordinated and economical ISTS RLDC STU State Govt. ISTS lines State1 RPC Central Govt. Generating Companies • CTU/to provide non-discriminatory Open Access • Will not engage in trading and generation • For LTOA & MTOA nodal agency State2 CEA Licensees

13. Role of CEA (2.6) CEA (Central Electricity Authority) • will formulate short-term and perspective plans for transmission system • specify technical standards for construction of electrical plants, electric lines and connectivity to the grid • specify safety requirements for construction, operation and maintenance of electrical plants and electrical lines • specify grid standards for operation and maintenance of transmission lines • specify conditions for SEMs • Promote and assist timely completion of schemes • To collect and record electrical data- cost, efficiency • To carry out investigation ( Electrical system) • Shall Prepare National Electricity Plan (NEP)

14. State Power System Role of SLDC (2.6) SLDC – Apex body in a State Ensure compliance • Optimum scheduling and despatch • Monitor grid operations • Keep accounts of electricity transmitted • Activities of Real-time operation • exercise supervision and control Directions and exercise supervision and control Licensee, generating company, generating station, sub-station and any other concerned person Directions RLDC

15. Role of STU (2.8) STU • to undertake transmission of electricity through intra-state transmission system • to ensure development of an efficient, co-ordinated and economical intra-state transmission system Planning shall operate SLDC CTU State Govt. Intra-state transmission system RPC Generating Companies STU/to provide non-discriminatory Open Access Licensees CEA 15

16. Role of STU (2.8) STU • Planning • Coordination shall operate • Energy transfer • Efficient • Economical SLDC Provide non-discriminatory open access • CTU • State Government • Generartors • RPCs • CEA • Licencees Intra-state transmission system

17. 3. Planning Code for Inter-state Transmission Introduction Objective Scope Planning Philosophy Planning Criterion Planning Data Implementation of Transmission Plan

18. Introduction Inter-state Intra-State Intra-State STU CTU STU Transmission schemes for planning and coordination Transmission schemesfor planning and coordination CEA

19. Scope of planning code (3.3) Connected to/using/developing ISTS CTU ISGS GC ISTS SEBs STU Licensees IPP Objective • specify principles, • specify procedures • specify criteria • promote coordination • information exchange Generation/Transmission of energy to/from ISTS

20. Long-term plan (10-15 years) CEA • inter/intra state transmission system • continuously updated to reflectload projections and generation scenarios • NEP • Avoid congestion Planning Philosophy (3.4) Annual plan (5 year forward term) CTU • Identification of major inter state/regional lines including system strengthening schemes • Planning schemes shall also consider: CEA’s: • Long-term perspective plan • Electric Power Survey of India report • Transmission Planning Criteria and guidelines • RPC Feedback • NLDC/RLDC/SLDC feedback • CERC Regulations • Renewable capacity addition (MNRES)

21. Planning philosophy (contd...) • System strengthening schemes by CTU: • shall be done in consultation with CEA’sStanding Committee for Transmission System Planning: • Planning • On the basis of PPA • No PPA/ no consensus – CTU may approach CERC in accordance with CERC (Grant of Regulatory approval for Capital Investment to CTU for execution of ISTS) • Planning data: • submission by STUs/Users to CTU:

22. Planning philosophy (contd...) • Voltage management by: • capacitors, reactors, SVC and FACTs • similar exercise by STU • STU shall plan to evacuate power from ISTS • ISTS & intra-state transmission systems are complementary & interdependent • If LTA Applications require strengthening of intra-state transmission system – applicant shall coordinate with STU

23. Planning Criterion (3.5) Planning criterion ISTS’s security philosophyCEA guidelines a) Without load shedding or rescheduling of generation, ISTS shall withstand and secure against the following outages: • a 132 KV D/C line, a 220 KV /DC line, • a 400 KV S/C line, 765 KV S/C line • single Inter-Connecting Transformer (ICT ) • one pole of HVDC Bi-pole • Outage of 765 kV S/C line Without load shedding but could be with rescheduling of generation, ISTS shall withstand and secure against the following outages: • a 400 KV D/C line • a 400 KV S/C line with TCSC • both pole of HVDC Bi-pole line • Outage of 765 KV S/C line with series compensation

24. Planning Criterion (3.5) b) ISTS shall withstand the loss of most severe single system infeed without loss of stability c) Any one of the events defined above should not cause: loss of supply prolonged operation of frequency below and above limits unacceptable high or low voltage system instability unacceptable overloading of ISTS elements 24

25. Planning Data & Implementation d)All S/S (132 kV & above) shall have at least two transformers e)CTU will carry out reactive power compensation requirement of ISTS & at ISGS’ switchyard f)SPS may be planned by NLDC/RLDC in consultation with CEA, CTU, RPC & Regional entities – for enhancing transfer capability or to take care of additional contingencies

26. Planning Data & Implementation Planning Data (3.6) As per CERC (Grant of Connectivity, LTA and MTOA in ISTS and related matters) Regulations 2009 Implementation of Transmission Plan (3.7) Actual program of implementation of transmission lines, ICTs, reactors/capacitors and other transmission elements as per CERC (Grant of Connectivity, LTA and MTOA in ISTS and related matters) Regulations 2009 26

27. OBJECTIVE • Ensure the safe operation, integrity and reliability of the grid • Non-discriminatory • New/modified connection not suffer or impose unacceptable effects • In advance knowledge about Connectivity 4. Connection Code Comply with CEA( Technical Standards for connectivity to the Grid) 2007 Minimum technical & design criteria SCOPE CTU STU ISTS Users connected to ISTS or seeking connection to ISTS

28. Procedure for connection (4.4) • User seeking new/modified connection: • Shall submit an application on standard format in accordance with CERC (Grant of Connectivity, LTA and MTOA in ISTS and related matters) Regulations 2009 • CTU shall process as per above regulations

29. 4.5 Connection Agreement • Connection agreement would be signed by the applicant in accordance with CERC (Grant of Connectivity, LTA and MTOA in ISTS and related matters) Regulations 2009

30. Reactive Power Compensation 4.6.1 • by /STUs and Users in the low voltage systems close to the load points therby avoiding exchange of reactive power to/ from the ISTS • Already connected shall provide additional reactive compensation as per the quantum and time frame decided by the RPC in consultation with RLDC. • Installation and healthiness would be monitored by RPC

31. Data and Communication Facilities (4.6.2) reliable and efficient speech and communication system to be provided Users/STU/CTU shall provide systems to telemeter power system parameters Flow Voltage Status of switches Status of transformer taps Associated communication system to facilitate data flow up to appropriate data collection point on CTU’s system as specified by CTU in the Connection Agreement 31

32. System Recording Instruments (4.6.3) Data Acquisition System/Disturbance Recorder/Event Logging facilties/Fault Locator (including time synchronization equipment ) shall be provided and always kept in working condition Responsibility for safety (4.6.4) • CEA (Technical Standards for connectivity to the Grid), Regulations 2007 • CERC (Grant of Connectivity, LTA and MTOA in ISTS and related matters) Regulations 2009 • CEA (Safety Requirements for construction, operation and maintenance of electrical and electric lines) Regulations, 2008 32

33. International Connections to ISTS (4.7) • By CTU in consultation with CEA and MOP Schedule of assets of Regional Grid (4.8) • CTU and other transmission licensees shall submit by 30th Sep a schedule of transmission assets as on 31st March indicating ownership on which RLDC has operational control and responsibility.

34. 5. Operating Code

35. Operating philosophy (5.1) • objective of the integrated operation: • enhance overall operational reliability and economy • Cooperate and adopt Good Utility Practice • NLDC: • overall operation of National/Inter-Regional Grid • develop/maintain detailed internal operating procedures for national grid • RLDC: • overall operation of Regional Grid • develop/maintain detailed internal operating procedures for regional grid

36. Operating philosophy (5.1) SLDC: develop/maintain detailed internal operating procedures for State grid All licensee, generating company, generating station and any other concerned person: comply with directions of RLDC/SLDC e) round-the clock manning by qualified and trained personnel of: control rooms of NLDC, RLDC, SLDC, Power Plant, Sub Stations (132 kV & above) control centres of all regional constituents 36

37. System Security Aspects (5.2) • Synchronism: • all Users, CTU & STU • operate their power systems/stations in an integrated manner • No deliberate isolation of part of the grid: • except under emergency • safety of human/equipment • when instructed by RLDC • restoration to be supervised by RLDC in coordination with NLDC/SLDC

38. System Security Aspects (5.2) Important elements list at RLDC: not removed without RLDC’s consent or prior consent when specifically instructed list of important elements to be prepared and shall be put on website of NLDC/RLDC/SLDC emergency removal intimated to RLDC tripping, reason, likely time of restoration intimated to RLDC say within 10 minutes Important elements tripping to be informed to NLDC by RLDC Prolonged outage ------ sub-optimal operation----monitored by RLDC------report to RPC-------- finalise action plan for restoration 38

39. Restricted Governor Action (5.2(f)) • Thermal generating > 200 MW and hydro units > 10 MW on RGMO wef 01.08.2010 • Gas Units, Combined Cycle, wind, solar & nuclear exempted till CERC reviews • When frequency stabilise at 50.0 Hz FGMO would be intoduced • RGMO • For Frequency < 50.2 Hz no reduction in generation when frequency rises • Any fall in frequency generation should increase by 5% limited to 105% of MCR (thermal), 110% MCR (Hydro) • After increase in generation, the unit mey ramp back to original level at a rate of 1% per minute • At Frequency < 49.7 Hz ramp up could be at higher rate • governors: 3% - 6% droop • any exception: reason & duration to RLDC

40. System Security Aspects 5.2 (s) 40

41. DEMAND ESTIMATION FOR OPERARTIONAL PURPOSES Inform to RLDC/ RPC Wind Energy Forecast ATC/ TTC By 01.01.2011 – online estimation of demand for each 15 min block 41

42. Demand Management(5.4) • SLDCs shall control demand in the event of: • insufficient generating capacity/inadequate external transfer • breakdown/congestion problems • Demand disconnection • frequency: • below 49.7 Hz: shall initiate action to restrict their net drawal • below 49.5 Hz: requisite load shedding • Each User/STU/SLDC shall formulate contingency procedures and make arrangements. Contingency Procedure to be regularly updated and monitored by SLDC/RLDC • SLDC through respective SEBs/Discoms shall formulate and implement state-of-the-art demand management schemes- roatational load shedding/demand response (which may include lower tariff for interruptible load) etc. SLDC to furnish periodic report to CERC.

43. Demand Management(5.4.2(e)(f)(g)(h)) Interruptible load in four groups: Scheduled load shedding/power cuts Unscheduled load shedding UFR/df/dt loads SPS loads RLDC may direct to decrease drawal in contingency---SLDCto send compliance report SLDC may direct SEB/Discom/bulk consumer to curtail drawal and monitor RLDC shall devise standard, instantaneous, message formats Congestion – requisite load shedding or generation backing down . Implementation as per CERC ( Measures to relieve congestion in real time operation), Regulations, 2009 43

44. weekly report by NLDC (put on website): Performance of national/integrated grid daily report by RLDC (put on website): Performance of national/integrated grid Wind power injection quarterly report by RLDC : system constraints, reasons for not meeting the requirements, security standards & quality of service actions taken by different persons persons responsible for causing the constraints weekly report by RLDC (put on website): Frequency and voltage profiles Major generation & transmission outages Transmission constraints Instances of persistent/significant non-compliance of IEGC Instances of congestion Instance of inordinate delay in restoration Non-compliance of instructions of SLDCs by SEB/Discom RLDC shall provide information/report to RPC for smooth operation of ISTS Periodic Reports (5.5) 44

45. Operational Liaison (5.6) • Introduction a) requirements for the exchange of information in relation to Operations/Events on the total grid system which have had or will have an effect on: • National grid • the regional grid • the ISTS in the region • the system of a User/STU (the above generally relates to notifying of what is expected to happen or has happened and not the reasons why) b)Operational liaison function is a mandatory built-in hierarchical function of the NLDC/RLDC/SLDC/Users to facilitate quick transfer of information to operational staff

46. Procedure for Operational Liaison • Procedure for Operational Liaison a) Operations and event on the regional grid • before carrying out any operation, RLDC will inform User/SLDC/CTU whose system will be affected • immediately following an event, RLDC will inform the User/SLDC/CTU with details of what happened but not the reasons why • RLDC to NLDC if other region is going to be affected • immediately following an event, NLDC would keep all RLDCs informed b) Operations and events on a User/STU system • before carrying out any operation that will affect regional grid, constituent shall inform RLDC with details • RLDC to NLDC if other region is going to be affected • immediately following an event, the User/SLDC shall inform RLDC with details but not the reasons why • immediately following an event, NLDC would keep all RLDCs informed • Prolonged Forced outages – monitored at RPC level. RPC shall send a monthly report to CERC

47. Outage Planning (5.7) Introduction a) procedures for preparation of outage schedules for the elements of the National/Regional in a coordinated and optimal manner and the balance of generation and demand b) generation output and transmission system should be adequate after taking outages into account to achieve security standards c) annual outage plan for the financial year shall be prepared by RPC Secretariat and reviewed during the quaterly and monthly basis. ROR, wind & solar power to be extracted to maximum

48. proposed outage programmes by all concerned (30th Nov) draft outage programme by RPC Secretariat (31st Dec) final outage programme by (31st Jan) monthly review quarterly review next financial year Nov Dec Jan Feb Mar Review by RPC Secretariat: adjustments made wherever found to be necessary in coordination with all parties concerned Outage Planning Process

49. Outage Planning (5.7.4) In consultation with NLDC/RLDC In Emergency – RLDCs may conduct studies before clearance NLDC/RLDC are authorized to defer - grid disturbance - system isolation - partial black out in a state - any other critical event Latest detailed outage plan – updated Each user, CTU and STU shall obtain one final approval from RLDC RPC shall submit quarterly, half yearly reports to CERC indicating deviations 49

50. Recovery Procedures (5.8) Detailed plans/procedures for restoration of partial/total blackout regional grid develops RLDC consultations reviewed/updated annually Concerned Constituents RPC secretariat develop • Mock trials once every 6 months • DG sets to be tested on weekly basis- quarterly report to be sent to RLDC Detailed plans/procedures for restoration of partial/total blackout reviewed/updated annually