INDIAN ELECTRICITY GRID CODE AND OPERATION ISSUES SRLDC/Comml/IEGC/1 P. Bhaskara Rao, DGM...

INDIAN ELECTRICITY GRID CODE

AND

OPERATION ISSUES

SRLDC/Comml/IEGC/1

P. Bhaskara Rao,

DGM (Commercial & C &M),

SRLDC,Bangalore

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

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

SRLDC/Comml/IEGC

Major Milestone in Development of the IEGC Contd…

10) With Modifications ,revised IEGC issued on 22nd March 2002.

11) The New Revised IEGC is effective from 01-04-2006

SRLDC/Comml/IEGC/3

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

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

Structure of the IEGC

1) Role of RLDC,RPC,CTU, CEA, SLDCs and STUs etc. and their organisational linkages.

2) Planning Code for inter-State transmission system 3) Connection Conditions a) Procedure for connection to the ISTS b) Site responsibility schedule

SRLDC/Comml/IEGC/6

4) 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

5) Scheduling & Despatch Code

6) Inter –Regional Exchanges

7) Management of IEGC. SRLDC/Comml/IEGC/7

IEGC TO OPERATE ON THE PERIPHERY

INTER-STATE SYSTEM

X

SEB/STU SLDCSTATE GOVT. SERC

CENTRAL GOVT.

CEA

CERC RPC

CTU RLDC

X= L - G

INTRA-STATE SYSTEM

LOAD

SRLDC/Comml/IEGC/8

G G

LL

CHAPTER-2 ROLE OF RLDC, RPC, 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

SRLDC/Comml/IEGC

CHAPTER-2

ROLE OF RLDC, RPC, CTU ETC. & THEIR ORGANISATIONAL LINKAGES


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/ intrastatetransmission 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

SRLDC/Comml/IEGC

CHAPTER-2

ROLE OF RLDC, RPC, CTU ETC. & THEIR ORGANISATIONAL LINKAGES


Functions:

To undertake planning of outage of transmission system on monthlybasis.

To undertake operational planning studies including protectionstudies for stable operation of the grid.

To undertake planning for maintaining proper voltages throughreview of reactive compensation requirement through system studycommittee and monitoring of installed capacitors.

To evolve consensus on all issues relating to economy andefficiency in the operation of power system in the region.

SRLDC/Comml/IEGC/9

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

SRLDC/Comml/IEGC


The Regional Load Despatch Centre shall-

be responsible for optimum scheduling and despatch of electricity;monitor grid operations;

keep accounts of quantity of electricity transmitted through the regional grid;

exercise supervision and control over the Inter-Statetransmission 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

SRLDC/Comml/IEGC


The RLDC may give such directions ,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

SRLDC/Comml/IEGC


However, pending the decision of the Central Commission, the directions of the RLDC shall be complied with by the SLDC 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 / interregionaltransfer of power, covering contingency analysis andoperational 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

SRLDC/Comml/IEGC


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 OpenAccess 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

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

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

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

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 Power Committees(vi) Authority (vii) Licensees (viii) Any other person notified by Central Govt. in this behalf.

SRLDC/Comml/IEGC/13

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

Central Transmission Utility (CTU)

Until a Government company or authority or corporation isnotified by the Central Government, the Central TransmissionUtility shall operate the Regional Load Despatch Centre.

CTU shall not engage in the business of generation of electricity ortrading in electricity.

In case of Open access in Inter-state Transmission, the nodal agency for the long-term transmission access shall be the CentralTransmission 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

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

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 ISTS and Intra-State TS (updated continuously of the revisions in load projections and

generation scenarios).

• CTU to carry out the planning process from time to time for identifying major ISTS (incl. Inter-Regional TS) which shall fit in with the perspective plan of CEA and in consultation with various agencies

• To consider while planning => Perspective plan of CEA => EPS report of CEA => Transmission Planning Criteria and guidelines by CEA

SRLDC/Comml/IEGC/16

=>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 Regional Standing Committee constituted by CEA ,RPC, RLDCs,beneficiaries

• Transmission Plan (Prepared by CTU) includes.

=> Transformers, Reactors, Capacitors, SVCs FACTS => lSTS schemes open to private investors => Action taken to fulfil additional requirement

• STU to prepare plans based on CTU's plans

SRLDC/Comml/IEGC/17

Planning Criterion

. CEA's Transmission Planning Criterion .and other guide lines of CEA

. Loss of most severe single contingency viz outage of a 400kv s/c line,outage of one HVDC bipole,Outage of single severe 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

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

• 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

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

SRLDC/Comml/IEGC/21

CHAPTER-5 OPERATING CODE FOR REGIONAL GRIDS• Operating Policy - To be developed by RLDC in consultation with constituents

andshall be consistent with IEGC

System Security Aspects: • No opening of lines/elements 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 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

. Recommended rate for changing the governor setting (supplementary control) : 1% per minute or as per manufacturer’s limits

At freq. <49.5 Hz.all partly loaded gen to pick up fast

. 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 RPC

Operating Frequency Range

49.0- 50.5 Hz. Band • Regional constituents to provide automatic u/f and df/dt relays

SRLDC/Comml/IEGC/23

Operating Voltage Standards Range ( in kV)

Normal Maximum Minimum

400 420 360

220 245 200

132 145 120

Voltage StandardsStatutory Limits as per Section 54 of IE Rules, 1956

Limits under

IE Rules

Low Voltage Voltage <250 V ± 6%

Medium Voltage 650 V > Voltage >250 ± 6%

High Voltage 33 KV >Voltage >650 V ± 6% to –9%

Extra-High Voltage Voltage > 33 KV + 10% to –12.5%

SRLDC/Comml/IEGC/24

Frequency Standards

Frequency Band for safe operation of Steam Turbines and adopted in IEGC 49 -50.5 Hz.

50 Hz.

48.5 Hz. 49 Hz.51 Hz.

51.5 Hz.

SRLDC/Comml/IEGC/26

•Under Frequency and df/dt Load Shedding

• Scheme to be finalized in RPC forum

• RPC to ensure its effective application. With prior consent of RLDC can be kept out of service temporarily in case of extreme exigencies.

• RPC to periodically check and keep records of its findings.

Demand Estimation - by SLDCs to forecast demandDemand 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

Periodic Reports: A weekly report shall be issued by RLDC to all constituents of the Region and RPC

Secretariat and shall cover the performance of the Regional grid for the previous week viz.

a) Frequency profileMaximum and minimum frequency recorded daily and daily frequency variation index (FVI).

b) Voltage profileThe 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

Outage Planning By RPC 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 RPC Sectt.

31st Dec. RPC Sectt. To issue Draft annual Outage Plan

31st Jan. RPC Sectt. To issue Final annual Outage Plan .

Quarterly & Monthly

Review of Final Annual Outage Plan by RPC Sectt.

SRLDC/Comml/IEGC/29

Recovery Procedures

• For Region to be developed/updated annually by RLDC in consultation with constituents /RPC 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/RPC Secretariat for analysis; No blocking of any information/data required by RLDC.

SRLDC/Comml/IEGC/30

Reportable events

Any of the following events require reporting by RLDC/Regional constituent

1) Violation of security standards2) 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

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 measuresSRLDC/Comml/IEGC/32

C H A P T E R - 6 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/RPC 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 RPC 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

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 RPC Secretariat by Thursday noon for week ending Sunday . RPC 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 & RPC) for verification.

Commercial Mechanism * Availability Based Tariff

( a) Capacity Charge (b) Energy Charge (c) Adjustment for Deviations

SRLDC/Comml/IEGC/34

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, SRPC.

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

1000

800

600

400

200

00 6 12 18 24

Forecast ex-bus capability of power plant

SEB - A’s entitlement (40%)

SRLDC/Comml/IEGC/36

MW

---

--

TIME in HOURS ----

SETTLEMENT SYSTEMFor the day: 0000 hrs. to 2400 hrs.

Central Generating Stations 1 2 3

Ex-Bus Capability x1 x2 x3(Forecast) ____ ___ ___

SEB-A’s share a1 a2 a3SEB-B’s share b1 b2 b3SEB-C’s share c1 c2 c3

For a particular 15 minute time block

SEB-A’s requisition a’1 a’2 a’3SEB-B’s requisition b’1 b’2 b’3SEB-C’s requisition c’1 c’2 c’3

___ ___ ___CGS’s schedule x1’ x2’ x3’

MW

SRLDC/Comml/IEGC/37

SETTLEMENT SYSTEMTotal capacity charge payable to CGS-1 for the day

= x1 * capacity charge rate of CGS-1Total Energy charge payable to CGS-1 for the day

= x1’ * Energy charge rate of CGS-1 4

Total capacity charge payable by SEB-A for the day

= a1 * capacity charge rate of CGS-1

+ a2 * -do- CGS-2

+ a3 * -do- CGS-3Total Energy charge payable by SEB-A for the day

= (a1’) * Energy charge rate of CGS-1 ( 4 )

+ (a2’) * -do- CGS-2 ( 4 )

+ (a3’) * -do- CGS-3 ( 4 )

All capacity charge and Energy charge payments to be made by SEBs directly to CGS.

SRLDC/Comml/IEGC/38

SETTLEMENT SYSTEM

Actual (metered) injection of CGS-1 in the time block = X1 MWh.

Excess injection = (X1 – x1’ ) 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 = a1’+a2’+a3’ = 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

49.0 49.8 50.249.4 50.6 Hz

Incremental Cost (Paise/kWH)U

I

Pri

ce

System Frequency

Sta

tion

Gen

erat

ion

75 %

25 %

0 %

50 %

420

280

140

0

100 %

Pool Price

MA

NU

AL

LO

AD

-SHE

DD

ING

DIE

SEL

GE

NR

, DE

PLE

TE

D H

YD

RO

GA

S - TU

RB

INE

NO

RM

AL

HY

DR

O

LO

AD

-CE

NT

ER

CO

MB

INE

D C

YC

LE

PIT - H

EA

D

NU

CL

EA

R

OV

ER

FLO

WIN

G H

YD

RO

Typical Graph Depicting Pricing of Unscheduled Interchanges w.r.t. System Frequency

SRLDC/Comml/IEGC/40

Scheduling Process

On Day-l

9 AM ISGSs advise foreseen plant-wise ex- . power plant MW, MWh * capability for next day

10 AM RLDC advises SEBs their MW, MWh* shares in foreseen ISGSs' availability

3 PM SLDCs furnish their ,time-wise MW requisition from the above, and schedule of bilateral exchanges, if any

5 PM RLDC issues' despatch schedules' for ISGSs and 'net drawal schedules' for SEBs, for each hour the next day starting at midnight

10 PM SLDCs may inform any change of the above or bilateral exchanges to RLDC, if required by any new development during the day

11 PM Schedules frozen for the next day. RLDC Issues final drawal schedules to each State & Despatch schedule to each ISGS

SRLDC/Comml/IEGC/41

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 t Any State may revise drawal schedule from any/all ISGS Any ISGS may revise their foreseen capability

Time block t+3 RLDC to issue revised ‘drawal schedules' and despatch schedules

SRLDC/Comml/IEGC/42

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

5 paisa per unitSRLDC/Comml/IEGC/43

SRLDC/Comml/IEGC

INTER-REGIONAL EXCHANGES

PRESENT SYSTEM

India has two (2) synchronous power systems today: (a) Northern, (NR-WR-ER-NER), and (b) Southern (SR)

The Northern system is synchronously connected through the 400 kv D/C GORAKHPUR- MUZAFFARPUR with ER and also through two (2) back to back HVDC links: (a) 2x250 MW Vindhyachal (NR-WR), and (b) 1x500 MW Sasaram (ER-NR).

The Southern system is connected to Northern system mainly through three (3) HVDC links: (a) 2x1000 MW Talcher-Kolar (ER-SR), (b) 2x500 MW

Gazuwaka (ER-SR), and (c) 2x500 MW Chandrapur (WR-SR).

ER and WR are presently synchronized through the 400 kV D/C Rourkela-Raipur line, and three (3) 220 kV circuits between Budhipadhar and Korba.ER and NER are synchronized through the 400 kV D/C Malda-Purnea/Binaguri-Bongaigaon line and 220 kV D/C Birpara-Salakati line.

SRLDC/Comml/IEGC/43

SRLDC/Comml/IEGC


SCHEDULING/SETTING AND OPERATION OF TALCHER-IISTPS/TALCHER-KOLAR HVDC:

4x500 MW Talcher-II STPS, though located in Orissa in Eastern region, is fully assigned to the Beneficiaries in Southern region. Also, it is synchronized with the Eastern region

Talcher-II STPS shall advise the SRLDC (with copies to ERLDC and Talcher HVDC terminal) the ex-power plant MW and MWh capabilities for the next day, by 9 AM every day. The SRLDC

shall then interact with the SLDCs of SR, and convey the dispatch schedule of Talcher-II for the next day to Talcher-II STPS, with copies to ERLDC and Talcher HVDC terminal, by 5 PM.

Any changes in foreseen power plant capability and in Beneficiaries’ requisitions shall be coordinated by SRLDC, and final dispatch and drawal schedules for the next day shall be issued by SRLDC by 11 PM. Any bilateral exchanges of Talcher-II (for unrequisitioned capability, if any) shall also be included in the schedules issued by SRLDC.

SRLDC/Comml/IEGC/43

SRLDC/Comml/IEGC


SCHEDULING/SETTING AND OPERATION OF TALCHER-IISTPS/TALCHER-KOLAR HVDC:

The base MW level for Talcher-Kolar HVDC link at Talcher end shall be separately advised by SRLDC to Talcher HVDC terminal. It need not be equal to the Talcher-II dispatch schedule, since power can flow to SR via other routes as well, i.e., Gazuwaka HVDC and Chandrapur HVDC. (The HVDC settings are to be optimized by SRLDC).

CEA, ERLDC, SRLDC, NTPC and Powergrid shall jointly work out and implement the required inter-tripping/runback arrangements between Talcher-II STPS and Talcher-Kolar HVDC link.

SRLDC/Comml/IEGC/43

MANAGEMENT OF IEGC

The Indian Electricity Grid Code (IEGC) shall be specified by the (CERC) as per section 79 (1) (h) of the Electricity Act, 2003. Any amendments to IEGC shall also be specified byCERC only.

The IEGC and its amendments shall be finalized and notified adopting theprescribed procedure followed for regulations issued by CERC.

The requests for amendments to / modifications in the IEGC and forremoval of difficulties shall be addressed to Secretary, CERC, for periodicconsideration, consultation and disposal.

Any dispute or query regarding interpretation of IEGC may be addressedto Secretary, CERC and clarification issued by the CERC shall be takenas final and binding on all concerned.

The (SERC) shall specify the Grid Codes for operation of the respective intra-State system as per section 86 (1) (h) of Electricity Act, 2003, ensuring that they are consistent with the IEGC.SRLDC/Comml/IEGC/44

SRLDC/Comml/IEGC/47

SRLDC/Comml/IEGC

Additional Inter-Regional Links – By 2006

Name of the link Capacity(MW)

East-North

Muzaffarpur – Gorakhpur 400kV D/c (Quad) 2000

Sub-total 2000

Inter-regional capacity - Present 9500

GRAND TOTAL 11500

SRLDC/Comml/IEGC

Salakati

Bongaigaon

Birpara

Malda

Dehri

Sasaram

Sahupuri

AllahabadNorth-eastern

Eastern

Northern

Belgaum

Kolhapur

Budhipadar

Rourkela

Korba

Raipur

Auraiya

Malanpur

Western

Southern

Balimela

Upper Sileru

Chandrapur

Ramagundam

Jeypore

Gazuwaka

Singrauli

Vindhyachal

Talcher

Kolar

Kota

Ujjain

Inter-regional Links – By 2006

Gorakhpur Muzaffarpur

Nagjhari

Ponda

900 MW

2650 MW 1200 MW

3150MW1400 MW

1650 MW

ESC TO EXIT

SRLDC/Comml/IEGC

Additional Inter-regional Links – By 2007

Name of the link Capacity(MW)

East-North

Patna – Balia 400kV D/c (Quad) 2000

Biharshariff – Balia 400kV D/c (Quad) 2000

Sub-total 4000

East-West

Ranchi- Sipat 400kV D/c with series compensation 1200

Sub-total 1200

East-South

Upgradation of Talcher-Kolar HVDC bipole 500

Sub-total 500

West-North

Gwalior – Agra 765kV S/c (initially ch. at 400kV) 1200

Sub-total 1200

Inter-regional capacity – By 2006 11500

GRAND TOTAL 18400

SRLDC/Comml/IEGC

Salakati

Bongaigaon

Birpara

Malda

Dehri

Sasaram

Sahupuri

Allahabad North-eastern

Eastern

Northern

Belgaum

Kolhapur

Budhipadar

Rourkela

Korba

Raipur

Auraiya

Malanpur

Western

Southern

Balimela

Upper Sileru

Chandrapur

Ramagundam

Jeypore

Gazuwaka

Singrauli

Vindhyachal

Talcher

Kolar

Kota

Ujjain

Inter-regional Links – By 2007

Gorakhpur Muzaffarpur

Balia Patna

BiharshariffBalia

SipatRanchi

Agra

Gwalior

Nagjhari

Ponda

2100 MW

6650 MW 1200 MW

3650MW1400 MW

2850 MW

SRLDC/Comml/IEGC

KOLAR SPECIAL PROTECTION SCHEME

INDIAN ELECTRICITY GRID CODE AND OPERATION ISSUES SRLDC/Comml/IEGC/1 P. Bhaskara Rao, DGM...

Documents

Transcript of INDIAN ELECTRICITY GRID CODE AND OPERATION ISSUES SRLDC/Comml/IEGC/1 P. Bhaskara Rao, DGM...