Wind Farm Wake Models From Full Scale Data

This investigation is part of the EU FP7 project “Distributed Control of Large-Scale Offshore Wind Farms”. The overall goal in this project is to develop wind farm controllers giving power set points to individual turbines in the farm in order to minimise mechanical loads and optimise power. One control configuration examined is distributed control where turbines only communicate with their nearest upwind neighbors. Design of such controllers needs wake models and these models should ideally be distributed. This paper compares two simple multiple wake models for this purpose. The study is based on real full scale data. The modelling is based on so called effective wind speed. It is shown that there is a wake for a wind direction range of up to ± 20 degrees. Further, when accounting for the wind direction it is shown that the two model structures considered can both fit the experimental data. However, both models estimate a weaker wake than suggested by the well known Jensen model.