1.8_Bleeg: Correcting for the impact of blockage on measured power curves

Measurements and CFD-based analyses indicate that the undue influence of blockage will often cause a power performance measurement (PPM) to materially deviate from the true performance of the test turbine, usually in such a way as to make the turbine appear more energetic than it actually is. This presentation explains how to estimate and correct for this bias by accounting for (1) the impact of test turbine induction on the PPM mast wind speed and (2) the influence of the surrounding turbines on the wind speed relationship between mast and test turbine. The correction methodology is then applied to CFD simulations of a generic wind farm, using a range of typical power performance mast locations to represent a large number of measurement configurations. The results indicate that the correction factors needed to offset the undue impact of blockage can be quite sensitive to the details of the test configuration as well as to site-specific factors, such as atmospheric stability and wind farm layout.