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Lecture 1

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POWER POINT PRESENTATION

ON

POWER SYSTEM & OPERATION CONTROL

Gandhi Institute of Eduction & Technology

Baniatangi,Khurda

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Some history

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Power grid architecture

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Figure: Final report on the August 14 2003 blackout in the US and Canada, Federal Energy Regulatory Commission (FERC), Apr. 2004.

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“Most significant engineering achievement of 20th century,” National Academy of Engineering report 2010.

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Course overview: Thermal Units

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Course overview: Economic Dispatch

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  • How to allocate MW outputs to generators to minimize operation cost?
  • Economic dispatch is a resource allocation problem.

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Course overview: Unit Commitment

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80

100 120 140 160 180

50

0 20 40 60

60

110

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100

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90

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80

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70

Hours

Total demand [GWh]

February 8−14, 2015

September 9−15, 2015

Figure: Electricity demand in Mid-continent Independent System Operator (MISO).

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  • Electricity load exhibits large variations across time.
  • Which generators should be on/off-line at each time?

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Course overview: Transmission System Effects

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Network-Constrained ED:

avoids transmission line overheating

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Optimal Power Flow:

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  • enforces voltage magnitude constraints
  • manages reactive power
  • incorporates transmission losses

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Contingency analysis:

Security-Constrained OPF (SC-OPF)

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Power system operations

Figure: Source [R1].

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Timescale of power system operations

Figure: Source [R2].

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Generation units

  • Three-phase AC voltage system with controlled frequency and magnitude
  • Broadly divided into:
    • thermal plants (coal, nuclear, natural gas, oil)
    • hydroelectric plants
    • renewables (wind farms, solar panels)
  • Different technologies vary in capital, maintenance and fuel costs

e.g., nuclear and hydro have high capital costs but low operating costs

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  • To see the current US electricity mix, check

https://www.washingtonpost.com/graphics/national/power-plants/

  • Due to load cycles and for reliability issues, there are more generators than needed. How do you pick the most economically efficient generation mix?

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Thermal plants

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  1. Burned fuel in boiler produces steam

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  • Steam converted to mechanical energy in turbine

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  • Generator converts mechanical to electric energy

Location: away from urban centers and close to water resources.

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Natural gas turbine plants

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T

Gas turbine

Gas

Burner

Gas turbine plant

Combustion

gases

Air

Compressor

G Generator

Network

a.c.

T

Gas turbine

Generator G

Gas

Burner

Combined Cycle Gas Turbine plant

Combustion

gases

Air

Compressor

Steam

T

Steam turbine

Generator G

Heat interchanger

Water

a.c.

Network

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Increased efficiency 60%; low emissions; reasonable investment costs

Peakers: fast-responding units in periods of high demand

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Nuclear power plants

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Baseload units: together with large coal plants operate almost always at max. Concerns related to catastrophic events and radioactive waste.

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Hydroelectric plants

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  • Turbine converts hydraulic to mechanical energy.
  • Generator converts mechanical to electric energy.
  • Types:
    1. Impoundment;
    2. diversion (run-of-the-river); and
    3. pumped storage.

First option in developing countries: avoid floods and control river navigation.

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Impoundment hydroelectric plant operation

Figure: Hydroelectric plant [R1].

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Pumped storage

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Figure: Ludington bumped storage plant.

Consume power at low-price hours (overnight) to pump water upwards. Regular operation (downward water flow) at high-price hours.

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Boiler-turbine-generator units

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  • valve between boiler and turbine controlling steam flow
  • gross vs. net power produced (2-10% for auxiliary power system)
  • To optimize generation mix, need relationship between net power and cost.
  • Water in hydro is free; assign cost for controlling reservoir levels.
  • Hydros are typically optimized over long periods of time.
  • Renewable resources can be treated like load.

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Thermal unit cost curves

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Input-output curve H(P ): fuel rate [MBtu/h] vs. net power output [MW]

Fuel-cost curve C(P ): multiply H(P ) by fuel cost [$/MBtu] to get [$/h]

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  • derived from calculations or test data
  • approximated by piece-wise linear or quadratic curves
  • maintenance and investment costs usually included

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Incremental cost curve

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Incremental fuel-cost curve IC(P ): the derivative of C(P ) [$/MWh]

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  • (incremental) fuel-cost curves routinely used in economic dispatch
  • generation limits (Pmin, Pmax)

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Heat-rate curve

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Heat-rate curve: the ratio H(P )/P [Btu/kWh]

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  • curve’s minimum is the most efficient operation point