Complex terrain and growing wind energy converters (WEC) in wind parks generate increasing interest in determining wind profiles and turbulence besides the general forecast of annual energy production. Increasing hub heights and growing rotor diameters of advanced WEC make SODAR systems a valuable alternative to meteorological towers. SODAR systems provide wind profiles as well as turbulence information over the entire height of large turbines. With SODAR measurements at WEC testing field in Grevenbroich in comparison to sonic and cup anemometers the usability of qualified wind and turbulence data from a SODAR are verified.
Results from simultaneous measurements of cup anemometers, ultra-sonic anemometers and the SODAR system show the differences and the compatibility between them. But they also show their suitability for wind measurement and turbulence determination. Site calibration with 2 ultra-sonic anemometers at 50 m height above ground level and an ultra- sonic anemometer and the SODAR thereafter prove the close agreement between these different measuring methods. The same result can be drawn from a comparison of a SODAR and a calibrated cup anemometer at 50 m height.
To complete the spectrum of comparisons in wind speeds an experiment of a European project (WISE) is quoted for profiles at 5 different heights.
The relationship between turbulence data of the different devices (cup and ultra-sonic anemometers with SODAR) referring to accepted guidelines like IEC 61400-1 allow the conclusion that it is possible to check a site for turbulence intensity and intensity profile with a SODAR to make sure that mechanical loads are resumed well.
Finally a power performance curve of a cup anemometer and a SODAR are compared.