Environmental Engineering Reference
In-Depth Information
60
55
50
45
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35
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15
10
5
0
20
Wind speed
Power
18
16
14
12
10
8
6
4
2
0
02
4
6
8
10 12
Time, hours
14
16
18
20
22
24
FIGURE 8.19 Enertech 44 performance with clean blades after rain, April 17, 1986. Maximum power is close
to 50 kW, the rated power.
turbine (72 m diameter, 1,500 kW) [30]. There was no reduction in the power curve because the
active stall provides complete compensation for moderately contaminated blades, and there was a
slight reduction around the knee of the power curve for severely contaminated blades. There was
a slight reduction in the power curve in the lower wind region for extremely contaminated blades.
However, the power still reached nominal rates at a wind speed larger than the rated one, but there
was a significant reduction in high winds beyond that point. The compensation for blade roughness
is another reason for using active stall over passive stall. The effect of blade roughness on energy
production is the reason airfoils with less sensitivity to blade roughness have been designed specifi-
cally for wind turbines.
20
60
55
50
45
40
35
30
25
20
15
10
5
0
Wind speed
Power
18
16
14
12
10
8
6
4
2
0
024
6 8 0
Time, hours
12
14
16
18
20
22
24
FIGURE 8.20 Enertech 44 performance with dirty blades, April 13, 1986. Maximum power leveled off
around 32 kW.
 
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