Environmental Engineering Reference
In-Depth Information
Source:
data from Enercon, 1997
Figure 5.13
Generator Active Power and Power Coefficient against
Wind Speed for the 500-kW Enercon E-40 Wind Generator
and the rotor is turned out of the wind if possible. The different wind speeds
have the following typical ranges:
• cut-in wind speed
v
cut-in
= 2.5-4.5 m/s
• design wind speed
v
D
= 6-10 m/s
•
nominal wind speed
v
N
= 10-16 m/s
•
cut-out wind speed
v
cut-out
= 20-30 m/s
•
survival wind speed
v
life
= 50-70 m/s.
It must be considered that some companies give their generator curves for wind
speeds at a height of 10 m, others at hub height (40-100 m). Figure 5.13
shows the generator active power and the power coefficient for a variable-
speed 500-kW wind turbine as a function of the wind speed.
Limiting power output and storm protection
The power that can be taken from the wind varies with the wind speed. After
reaching the nominal power, the power should remain constant for wind
speeds greater than the nominal wind speed because the turbine and generator
cannot handle more power. Therefore, a wind power plant must limit the
power with one of the two following methods:
•
stall control
•
pitch control.
