The impact of blockage and wakes on seven power performance tests conducted at two wind farms

Blockage and wakes can potentially influence wind turbine power performance measurements (PPM), distorting the measured power curve relative to the true performance of the test turbine. In this study, we take a previously proposed method to correct for the impact of blockage and wakes and test it on seven PPM conducted in simple terrain at two wind farms. Each PPM was completed according to the prevailing standard from the International Electrotechnical Commission. The correction factors derive from Reynolds-Averaged Navier-Stokes simulations of the two wind farms, and we apply these factors to the measured wind speed data on a record-by-record basis. The wind speed corrections clearly reduce variability in the measured power coefficients for the three PPM affected by long-distance wakes. The corrections do not reduce performance variability within the other four PPM. They also do not reduce differences in measured performance between the turbines at each wind farm, though numerical site calibrations do. Given these results, and considering uncertainty in the measurements, including confounding influences like terrain and turbine differences, validation against many more PPM is likely needed to adequately assess the reliability and utility of the correction method.