Civil Engineering Reference
In-Depth Information
FIGURE 5-13
Original land use continues in a wind farm in Germany. (Source: Vestas Wind Systems, Denmark
With permission.)
to operate with variable speed. Two possible schemes used with the variable-
speed operation are as follows:
5.6.1
Constant Tip-Speed Ratio Scheme
This scheme is based on the fact that the maximum energy is extracted when
the optimum tip-speed ratio is maintained constantly at all wind speeds.
The optimum TSR is a characteristic of the given wind turbine. This optimum
value is stored as the reference TSR in the control computer. The wind speed
is continuously measured and compared with the blade tip speed. The error
signal is then fed to the control system, which changes the turbine speed to
minimize the error (
Figure 5-14
)
. At this time the rotor must be operating at
the reference TSR generating the maximum power. This scheme has a dis-
advantage of requiring the local wind speed measurements, which could
