Design and implementation of combined frequency/oscillation damping controller for type 4 wind turbines

This paper proposes a topology for the combined frequency/oscillation damping active power control loop for type 4 wind turbines. In order to assess the effects of standard transient network frequency support control loops and the established controller topology on frequency response a quasi steady-state frequency model for the wind turbine equipped with frequency support auxiliary loop is developed. The performance of the proposed controller is then validated on a 14-generator benchmark system with installed wind capacity implemented in an Electromagnetic Transient Program. Positive impacts of the controller on frequency response, long-term frequency stability and inter-area oscillatory mode are demonstrated. The issues of controller tuning with respect to torsional interactions are also discussed.