Reactive Power Coordinated Control Strategy for Offshore Wind Farm Cluster with VSC-HVDC Transmission

Large-scale offshore wind farm cluster grid may bring some influences on static voltage stability. A kind of coordinated reactive power control strategy of offshore PMSG wind farm cluster connected to system including via VSC-HVDC transmission is proposed. Aiming at the rapid voltage recovery of network fault nodes, this strategy makes full use of the transmission characteristics of ac submarine cable and adopts the reactive power control strategy combining local control and remote control mode. Firstly, the reactive power control nodes in the AC / DC flexible transmission system were determined and voltage / reactive power sensitivity of each control node was calculated. Secondly, the maximum reactive power control capacity of each control node was solved based on the operation state and power flow distribution of the reactive power compensation. Finally, the reactive power control capacity was computed using improved genetic algorithm. The improved genetic algorithm for mutation process improves the computational speed. The result in a modified IEEE 39-bus system shows that the strategy of reactive power can improve the supporting role of offshore wind farm cluster for grid voltage.