KERALA STATE ELECTRICITY BOARD - KSEB - Overview

Kerala State Electricity BoardA Technical Presentation

Melvin Koshy

College of Engineering, Trivandrum

August 18, 2010

Melvin Koshy Kerala State Electricity Board

Introduction

Power sector - One of the important sectors fuelling the GDPgrowth

Private sector participation has increased recently - pushed bypolicies and regulations

Complexities increased manifold

Renewable energy - thrust area - REC

R & D initiatives required in optimising system management -shift from command control to contractual control


World Power Scenario

Demand for electricity is closely linked to economic growth

The share of electricity in total energy consumption

2002 - 16% 2030 - 20%

During past thirty years, growth of global economy - 3.3% peryear electricity demand - 3.6%

Electricity demand by 2030 would be doubled


Probable Scenario in 2030

Developing countries demand tripled

Developed countries, growth of 1.4% per year

Indonesia - 5.2%India - 4.9%China - 4.5%

Sectoral growth

Residential electricity consumption - 119%Services sector - 97%Industry - 86%


Sources of Power

Dominant fuel in the past - Oil

Last 30 years - More Coal

Present Trend - More LNG

Gas preferred to coal for

environmental advantageslower capital costsoperational flexibility


Sources of Power

Nuclear stations

Long term cost advantage as base loadMajor impediment - safety hazards

Hydro

Environmental issuesCost of development in the rural areas.Salination of river deltasErosion and siltation of damsAlienation of productive farmlandDestruction of forests


World Power Scenario

Fossil Fuels

Increased pollution due to sulphur dioxide, nitric oxides andcarbon dioxideTrans-boundary issues such as acid rainStratospheric ozone depletionGreenhouse effect

By 2030, power generation will account for nearly half ofworld consumption of natural gas


Power scenario in India

Growth of Economy - 7 – 8%

Power sector growth required - 10 – 12%about 12000 MW capacity addition per annum

Per–capita consumption - 733 kWh

Projected for 2012 - 1000 kWh

Power shortage

8% on average basis12% on peaking basis

Hydro Power

Potential - 150,000 MWUtilised - 32,000 MWTarget for 2017 - 50,000 MW


Installed Capacity


Power System Operation - Basics


Management of Electricity

Electricity cannot be stored in large quantities

Production to match with consumption in real-time

Power flow depend only on the laws of Physics

Electrical Network needs to be Controlled andCoordinatedtechnically and economically

Hence, a need for Load Dispatching


Load Dispatching

Coordination of

Generation systemTransmission systemDistribution system andLoad

Ensuring

SafetyStablityPower qualityEconomical rate

Optimum Load – Generation Balance


Functions of Load Dispatch

Power System ControlObjective: Safe and Secure Operation

Control parameters

Voltage

Frequency

Power System CoordinationObjective: Most economic operation

Control parameters

Schedule of generation

Arrangement of transmission system

Crisis Management


Load Generation Balance


Load Generation Balance

Real time

The actual demand has to be met with power availabilitySources

Internal from the control area itselfExternal to the control areaThermalHydelOthers

Long term (Control period)

Energy requirement for the control period is to be met


Demand of Control Area

Demand depends on

Weather

Social factors - festivals/holidays, examinations, major cricketmatches etc.

Political factors

Availability of transmission, distribution system due totechnical reasons

Predictable/Unpredictable reasons


Integrated Operation

The power system is operated on integrated mode. This provides

Better stability

Better reliability

Low spinning reserve requirement

Possibility of economic operation

Requirements

Extensive transmission network

Complex control and coordination


India - Power Map

Indian Power System is dividedinto Five Regional Grids

Northern Region

Western Region

Eastern Region

North-Eastern Region

Southern Region


Electrical Regions


All India Power demand Peak in MW

April 2010 April ’09 - March 2010

Peak demand 121220 119166

Peak demand met 102894 104009

Deficit 18326 (15.1%) 15157 (12.7%)


Southern Region Power position Peak in MW




Deficit 2033 (6.5%) 3129 (9.7%)


Southern Region Power position Energy in MU




Deficit 2165 (10.6%) 14032 (6.4%)


Power System Control

Control parameters

Frequency – ACTIVE POWER

Voltage – REACTIVE POWER

Loading – POWER FLOW


Frequency Control

Control parameter: Active power

Generation to match with load at any instant

Generation control

Manual

Automatic

Load control

Consumers choice

Contingency

Imposed by utility


Generation control – Manual

Sources

Hydel

Thermal

Gas

Liquid Fuel

Combined cycle

Open cycle

Nuclear Non-Conventional

Wind

Solar

Small Hydel

Others


Automatic Control

Instantaneous response

Governor Control

FGMO

RGMO

Frequency based automatic schemes


Load Control

Power shortage

Constraints

Contingency

Imposed by utility

Load shedding

Energy shortage

Choices

Affordability

Choice for consumer

Power Cut


Demand Management

Starts acting when f < 49.7 Hz

Load shedding below f < 49.5 Hz

Automatic under frequency load shedding

Plain UFdf/dt

SCADA based selective remote tripping to maintain controlarea error at lower frequencies


System Performance Parameters

Main factors

Generation

Spinning ReserveSize of gridInterconnection

Transmissionn − 1

n − 2


Allowed Voltage variation (as per IEGC)

Nominal Maximum Minimum

765 800 728

400 420 380

220 245 198

132 145 122

110 121 99

66 72 60

33 36 30


Factors affecting voltage

Voltage balance – Reactive power

Reactive sources

ReactorsCapacitor banksTransmission line – SIL, length of line

Loading constraints

Compensation – Location


Power Map of Southern Region


Active power flow

Depend on laws of physics

KVL and KCL hold good

Principle - “ Power flow by displacement”


Principle of HVDC


Activities in Load Dispatching

Data Monitoring

Data Analyzing

Optimal Decision making


Data Requirement

Output of Generators

Power Flow through Grid

Inter State Power Flow

Bus Voltage

System Frequency

Reservoir Levels

Fuel Position

Power availability


Power System SCADA

SCADA – Supervisory Control And Data Acquisition

SCADA makes entire power system available to the operatorfor control

It also permits the operator to interfere in the grid by remoteswitching in exigencies

It is integrated up to national level with drill-down facility


Information flow


SCADA GUI - SLDC, Kalamassery


SCADA in Kerala

32 Remote Terminal Units covering all generating stations,220 kV substations and 110 kV grid stations Broadbandbackbone with OF/MW links

Radial connections through PLCC

Three sub load dispatch centres and one state load dispatchcentre


Control Levels in Power System

National Load Dispatch Centre, Delhi

Regional Load Dispatch Centres

State Load Dispatch Centres

Sub Load Dispatch Centres


Hierarchy of Controls


Power system Coordination

Parameter to be controlled - Cost

Control variables

Schedule of generators

Arrangement of transmission network

Basically an optimisation problem


India - Power Map

Interconnected grid

Generation outside geographicboundaries

Principle of displacement


Typical Demand Pattern


Constraints in Generation

Nuclear power - Strictly base load plant

Coal based - 75% to 100%, Limited start stops

Combined cycle - 75% to 100%, Limited start stops

Open cycle - Cost high

Hydel - Water discharge commitment, Spillage/Shortage ofwater


System based constraints

Transmission constraints

Voltage constraints

Minimum generation

Spinning reserve


Enforcement of optimisation - Tariff

Tariff determines charges, penalties and incentives

To facilitate enforcement of optimisation, Availability Based Tariff(ABT) was introduced, which has three components

Capacity charges (Fixed cost)

Energy charges (Variable cost)

Unscheduled interchange (UI charges)


Mechanism of the ABT

The commercial mechanism of the ABT disciplines of all threeentities in the grid - the generator, transmitter and thebeneficiaries

The UI charges combined with capacity charge on availabilitybasis facilitates the marketing of both capacity and energy ona continuous basis, and enforcement of grid discipline

“Availability Based Tariff ”is appropriate as it reflects allelements of capacity made available as well as capacity utilised


Unscheduled Interchange (UI)

Demand of the grid is not constant

Frequency of the grid is not constant

Depending on various conditions, the tie line flow varies frominstant to instant

Thus UI is unavoidable in an integrated network

UI can be harnessed effectively to the advantage of theconstituents if system permits

Rate depends on frequency


UI Rate for different frequencies w.e.f. 03-05-2010


Beneficiary UI


Generator UI


VAR Rates

Payable at10 ps./kVARH for

VAR injection at Voltages above 103% of rated voltage

VAR absorbed at Voltages below 97% of rated voltage

Receivable at 10 ps./kVARH for

VAR drawal at Voltages above 103% of rated voltage

VAR injection at Voltages below 97% of rated voltage


Merit order Dispatch


Trading of power

Act 2003 and Electricity policy recognises trading ofElectricity as a distinct activity

Open access is provided in transmission sector so that anyutility can buy power from any source in India or even fromabroad

Transmission charges are payable to the transmission company

Losses associated are to be borne


Necessity of electricity trading

Quality of power is determined by the overall behaviour of allagencies

Manufacturers (generators)Customers (SEBs/DISCOMs)Transporters (transmission and distribution agencies)

No agency is able to control the quality of his production orpurchase in an integrated network.

Power trading contributes to

Better grid conditionsGrid disciplineReduction of the overall cost


Players in the field

Trading can be

BilateralThrough traders approved by regulatory commissionsDirect

Through Exchanges

Indian Energy ExchangePower Exchange India Ltd.


Advantages of trading

Resources optimization

Reducing peaking shortage by ensuring transfer of electricityfrom surplus region to deficit region on day to day basis andeven on real time basis

Signal for investment in generation (Evident from the numberof generators coming up on merchant basis and willing to sellpower to the needy consumers by participating in tenderformalities)

Harnessing of various sources of power such as co-generation,captive, wind power etc.

Better utilisation of transmission assets effectively reduces theoverall transmission cost as Short term trading is done byutilizing the inherent margin of the transmission network


Transactions through power exchanges

Most of the trade in power exchanges is through day-aheadmarket.

The requirement/availability for the next day can be quotedon hourly basis.

There is no obligation on time period for offers, the quantumof requirement

Prices quoted are to be considered as true reflection of themerit order of purchasers.

The offered price by sellers is based on market conditions


Features of Power Exchanges

Pre-conditions like must buy for a time period, say off-peakalong with peak, day time with off-peak etc. are common

Ensure scheduling of the plant above technical minimumthroughout the day

Possibility of subsidising some portion of off peak sale withthe margin available during peak or day-time

Agreements for longer period-typically week ahead or monthahead

Swap covering several months also possible


Significance of Power Exchanges

Purchase can be restricted to the essential period alone incase of power shortage

This preserves the overall merit order-Even purchase for 4 h(say), peak at a rate higher than the costliest internal stationmay prove to be in merit order

Very low prices discovered in exchanges in some period can beutilised for meeting energy shortage


THANK YOU


KERALA STATE ELECTRICITY BOARD - KSEB - Overview

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