Abstract
Hitachi, Ltd. has developed 5MW class downwind wind turbines to meet the increasing demand for larger offshore wind turbine. Using ground mounted Doppler Lidar (ZephIR 300), Hitachi has conducted power curve test at Fukashiba, Ibaraki prefecture, Japan. It was found at this site, wind shear measured with Doppler Lidar varies significantly with wind direction. Scatter in the power curve was analyzed by means of power standard deviation for different corrections applied to the wind speed including wind shear, wind veer and turbulent intensity filtering. It was found that wind shear correction has the most effect on scatter mitigation for this test. Also wind correction was found to have an adverse effect for some wind speed bins. The corrected power curve showed very similar result to simulated power curve, which is obtained by applying turbulence intensity correction to steady power curve.
