A Coordinated Primary Frequency Control Method for DFIG-based Wind Farm (iSPEC 2020)

With the increasing number of wind turbine generators (WTGs) connected to the electricity network via power electronic devices, the issue of system frequency stability becomes quite challenging due to the decreased inertia. This paper presents a coordinated power control method for wind farm to participate in primary frequency regulation while minimizing the side effect of rotor speed distortion. The proposed control theme is made fully data-driven by fitting a dynamic model recursively from real-time measurements of WTGs and optimizing active power dispatch under model predictive control framework. Through coordinating the operation of WTGs as a group, the wind farm is capable of providing primary frequency regulation with flexible frequency droop characteristics, and the rotor state inside each WTG is dynamically optimized and stabilized to maintain the operation lifetime. Moreover, this coordinated control strategy can follow the dispatch signal from the upper control center by online adjusting the farm's droop ratio. A 9-bus case study which demonstrates the effectiveness of the proposed method is presented.