Assessment of loads and power generation for a wind farm utilizing Helix control strategy

Abstract This paper investigates the effectiveness of the Helix control strategy for a 3 × 3 wind farm in neutral atmospheric boundary layer flow using large eddy simulations of IEA 15MW wind turbines in terms of power production and blade and tower loadings. Various control scenarios are considered, with a maximum power gain of 7% obtained in the case where the first two columns of the wind farm are controlled with the Helix controller. It is shown that the power gain strongly depends on the phase difference of the first and second-column wind turbines’ Helix signal. However, we show that the optimum phase difference value can be estimated using the inflow velocity. The damage equivalent loads for the wind turbine blade and tower are calculated using a coupled aeroelastic solver. Compared to a baseline case with no Helix controller, the largest differences are seen for the flapwise blade bending moment where the DEL values increased by two-fold. The DEL differences for the blade edgewise, tower fore-aft, and tower side-to-side bending moments are found not to pose a limiting factor for the practical implementation of the Helix controller in real-world wind farms.