Voltage and reactive power control of a wind farm based on nine zone diagram

With the rapid development of wind power in China, the impact of large-scale wind farms on the power grid becomes increasingly serious. Among which, the voltage fluctuation at the PCC (point of common coupling), has attracted a lot of attention. In this paper, the effects of voltage and reactive power control on wind farms are analysed based on the nine zone diagram method. Firstly, the modified nine zone diagram for the wind farm substation is presented. And then, the characteristics of voltage and reactive power control are discussed from the viewpoint of modified nine zone diagram. Furthermore, the control strategy of voltage and reactive power is designed based on the modified nine zone diagram. Finally, simulations of an actual wind farm are done on to verify the feasibility and effectiveness of the proposed control strategy.