Environmental Engineering Reference
In-Depth Information
Wind speed
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Wind speed (m/s)
Power curve
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Wind speed (m/s)
Figure 3.4
Calculation of annual energy yield
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Yaw control: The entire nacelle is rotated about the tower to yaw the rotor out
of the wind. This technique is not commonly used.
Variable-speed wind turbines, using some form of power electronics to con-
nect the generator to the network, generally use pitch regulation at high wind
speeds, although stall regulation has also been used.
On all large wind turbines, the blades are constructed to form an airfoil section
designed to generate lift. The airfoil sections are similar to those found on aircraft
wings. These sections have well-defined characteristics depending on the angle of
incidence, sometimes known as the angle of attack.
A typical blade element airfoil section is shown in Figure 3.5.
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