KERALA STATE ELECTRICITY BOARD - KSEB - Overview
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Transcript of KERALA STATE ELECTRICITY BOARD - KSEB - Overview
Kerala State Electricity BoardA Technical Presentation
Melvin Koshy
College of Engineering, Trivandrum
August 18, 2010
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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
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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
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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%
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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
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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
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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
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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
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Installed Capacity
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Power System Operation - Basics
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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
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Load Dispatching
Coordination of
Generation systemTransmission systemDistribution system andLoad
Ensuring
SafetyStablityPower qualityEconomical rate
Optimum Load – Generation Balance
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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
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Load Generation Balance
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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
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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
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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
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India - Power Map
Indian Power System is dividedinto Five Regional Grids
Northern Region
Western Region
Eastern Region
North-Eastern Region
Southern Region
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Electrical Regions
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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%)
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Southern Region Power position Peak in MW
April 2010 April ’09 - March 2010
Peak demand 31087 32178
Peak demand met 29054 29049
Deficit 2033 (6.5%) 3129 (9.7%)
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Southern Region Power position Energy in MU
April 2010 April ’09 - March 2010
Peak demand 20410 220576
Peak demand met 18245 206544
Deficit 2165 (10.6%) 14032 (6.4%)
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Power System Control
Control parameters
Frequency – ACTIVE POWER
Voltage – REACTIVE POWER
Loading – POWER FLOW
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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
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Generation control – Manual
Sources
Hydel
Thermal
Gas
Liquid Fuel
Combined cycle
Open cycle
Nuclear Non-Conventional
Wind
Solar
Small Hydel
Others
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Automatic Control
Instantaneous response
Governor Control
FGMO
RGMO
Frequency based automatic schemes
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Load Control
Power shortage
Constraints
Contingency
Imposed by utility
Load shedding
Energy shortage
Choices
Affordability
Choice for consumer
Power Cut
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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
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System Performance Parameters
Main factors
Generation
Spinning ReserveSize of gridInterconnection
Transmissionn − 1
n − 2
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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
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Factors affecting voltage
Voltage balance – Reactive power
Reactive sources
ReactorsCapacitor banksTransmission line – SIL, length of line
Loading constraints
Compensation – Location
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Power Map of Southern Region
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Active power flow
Depend on laws of physics
KVL and KCL hold good
Principle - “ Power flow by displacement”
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Principle of HVDC
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Activities in Load Dispatching
Data Monitoring
Data Analyzing
Optimal Decision making
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Data Requirement
Output of Generators
Power Flow through Grid
Inter State Power Flow
Bus Voltage
System Frequency
Reservoir Levels
Fuel Position
Power availability
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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
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Information flow
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SCADA GUI - SLDC, Kalamassery
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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
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Control Levels in Power System
National Load Dispatch Centre, Delhi
Regional Load Dispatch Centres
State Load Dispatch Centres
Sub Load Dispatch Centres
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Hierarchy of Controls
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Power system Coordination
Parameter to be controlled - Cost
Control variables
Schedule of generators
Arrangement of transmission network
Basically an optimisation problem
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India - Power Map
Interconnected grid
Generation outside geographicboundaries
Principle of displacement
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Typical Demand Pattern
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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
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System based constraints
Transmission constraints
Voltage constraints
Minimum generation
Spinning reserve
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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)
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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
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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
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UI Rate for different frequencies w.e.f. 03-05-2010
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Beneficiary UI
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Generator UI
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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
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Merit order Dispatch
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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
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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
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Players in the field
Trading can be
BilateralThrough traders approved by regulatory commissionsDirect
Through Exchanges
Indian Energy ExchangePower Exchange India Ltd.
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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
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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
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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
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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
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THANK YOU
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