Deployment and control strategy of reactive power devices in large wind power collection stations

Due to the features of wind sources location and power grid structure, the development mode of wind power in China presents characteristics of building large wind power bases and connecting into bulk power grid at present and for a period of time in the future. Several 10GW-level wind power bases will be built in Hebei, Jiangsu, Inner Mongolia, Gansu, Xinjiang, Jilin according to the development plan made by National Development and Reform Commission, and some of these bases will be connected to power grid via 500kV or even 750kV lines. Consequently, the interaction between wind power and power system become greater. Since wind power has the characteristics of randomness, variability, intermittence, unpredictability and uncontrollability, the integration of wind power will inevitably bring some impact on the plan and operation of power system. The deployment of reactive power devices in wind power collection substation will help to improve the voltage stability of local power grid, to avoid the large-scale trip-off of wind turbines and to improve the capability of substation to exporting wind power. As to the development mode of wind power in China, this paper conducts a study on reactive power compensation of 500kV wind power collection substation in large wind power base. Principle that determines the capacity and type of reactive power devices will be developed considering the active power change and reactive power characteristics of wind power base. The type of dynamic compensation devices will be analyzed based on transient stability analysis. Finally, the technical requirements and control strategy of reactive power compensation devices in wind power collecting substation will be given.