17-1

Chapter 17

Electric Utility Applications

• These applications are growing rapidly

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HVDC Transmission

• There are many such systems all over the world

17-3

HVDC Poles

• Each pole consists of 12-pulse converters

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HVDC Transmission: 12-Pulse Waveforms

• Idealized waveforms

17-5

HVDC Transmission: Converters

• Inverter mode of operation

17-6

Control of HVDC Transmission System

• Inverter is operated at the minimum extinction angle and the rectifier in the current-control mode

17-7

HVDC Transmission: DC-Side Filters

Tuned for the lowest (12th harmonic) frequency

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HVDC Transmission: AC-Side Filters

Tuned for the lowest (11th and the 13th harmonic) frequencies

17-9

Effect of Reactive Power on Voltage Magnitude

• Illustration of the basic principle

17-10

Thyristor-Controlled Inductor (TCI)

• Increasing the delay angle reduces the reactive power drawn by the TCI

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Thyristor-Switched Capacitors (TSCs)

• Transient current at switching must be minimized

17-12

Instantaneous VAR Controller (SATCOM)

• Can be considered as a reactive current source

17-13

Characteristics of Solar Cells

• The maximum power point is at the knee of the characteristics

17-14

Photovoltaic Interface

• This scheme uses a thyristor inverter

17-15

Harnessing of Wing Energy

• A switch-mode inverter may be needed on the wind generator side also

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Interface with 3-Phase Utility Grid

• Uses a thyristor inverter

17-17

Interface of SMES

• Can be used for utility load leveling

17-18

Active Filters for Harmonic Elimination

• Active filters inject a nullifying current so that the current drawn from the utility is nearly sinusoidal