Sensitivity of Lillgrund Wind Farm Power Performance to Turbine Controller

The impact of the choice of the individual wind turbine controller on the power production of a wind farm is studied by means of large eddy simulations (LES) combined with aero-servo-elastic actuator disc representations of the rotors. The investigation includes both two typical controllers for pitch-regulated variable speed wind turbines and a simplified control strategy based on tabulated rotor speed and pitch as a function of the average velocity at the rotor. The simulations show that the power output of the individual wind turbines is strongly affected by choosing either a standard or simplified control strategy when they operate in the deep wake of upstream turbines. On the other hand, the sensitivity to control strategy is less significant for wind directions where the effective stream-wise distance between the turbines is larger.