Environmental Engineering Reference
In-Depth Information
A Pitch control
B Position sensor
C Latch
D Pitch power
E Remote power
F Tower logic,
computer, and
power
Anemometer
B
AC
F
E
D
Main shaft
Rotor
Gears
rpm sensor
slip rings
Generator
Utilities
lines
Ground logic,
computer, and
power supply
Power
contactor
figure 5.14
Block diagram for system with pitch control.
used because of the increased aerodynamic efficiency with blades in the run position for large
wind turbines.
5.6.1 N
of r m a l
o
p e r a t i of N
A
power curve
, power versus wind speed, describes the normal operation of a wind turbine
(Figure 5.15). Notice that difference in power output at low wind speed is due to difference in
the electric efficiency of the generators. At the cut-in wind speed the unit starts to rotate or produce
power, then reaches rated power (size of generator) at the rated wind speed and continues to produce
1000
800
600
400
200
0
0
5
10
15
20
25
Wind Speed, m/s
Cut in
Rated
Cut out
figure 5.15
Power curves for a rotor with two different generator sizes.
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