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Adviser ： Dr. Yuan-Kang WuStudent ： Ti-Chun YehDate ： 2013.05.01

Frequency Control and Wind Turbine Technologies

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II. Wind Generation Technology

Wind turbine generators (WTGs) can be divided into two basic categories:

1.Fixed speed wind turbine generators

2.Variable speed wind turbine generators

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A fixed-speed WTG generally uses a squirrel-cage induction generator to convert the mechanical energy from the wind turbine into electrical energy.

Variable-speed WTGs can offer increased efficiency in capturing the energy from wind over a wider range of wind speeds.

Doubly fed induction generator (DFIG) and multipole synchronous generator are popular types of variable speed WTGs.

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The captured aerodynamic power is given by the following equation and depends on air density ρ, swept area of wind turbine A, the power coefficient Cp , and wind speed μ

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The system is examined for increasing installed wind capacities under three different scenarios. These scenarios are carefully chosen to represent the most extreme situations that could occur on the Ireland electricity system.

(1) Winter Peak (WP) is a best-case scenario.

(2) Summer Night Valley (SNV) is a worst-case scenario.

(3) Summer Day Valley (SDV)

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Considering that the ROCOF protection setting for generators connected to the Ireland electricity system is 0.5 Hz/s, it can be seen from Fig. 3 that these protection settings would not be exceeded for the winter peak scenario.

(WP) is a best-case scenario.

(SNV) is a worst-case scenario.

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The frequency nadir is detrimentally affected if DFIG WTGs displace conventional generators and is largely unaffected if fixed-speed WTGs displace conventional generation.

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While Table II illustrates that maximum ROCOF is independent of wind turbine technology, the frequency nadir is found to depend on the type of wind turbine technology.

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Adviser ： Dr. Yuan-Kang WuStudent ： Ti-Chun YehDate ： 2013.05.01

Demand Response in an Isolated System With High Integration

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II. Model Approach

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THE ENDTHE END

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