Optimal reactive power allocation method for an offshore wind farm based on novel power operation region of PMSG

To mitigate the voltage fluctuation of offshore wind farm with long-distance transmission, an optimal reactive power allocation method is proposed for permanent magnet synchronous generator-based (PMSG-based) wind farm participating in reactive power regulation of power system. Considering the wind conditions and maximum capacity of grid-side converter, this paper investigates the novel power operation region of wind turbine which depicts the maximum reactive power upper limit of single PMSG. Further, since each wind turbine can produce different power capacity as result of wake effect and collection line, an optimization strategy is designed for reactive power allocation under the premise that the total active power remains unchanged. By adjusting the power of each PMSG within power operation region, the proposed strategy can fully improve the voltage support ability without using static var generator (SVG). Case study is carried out to verify the advantages of proposed method in PSCAD.