Research On Automatic Voltage Control Strategy And Algorithm Of Wind Farm

With the increasingly serious problems of environment and resources, the wind power generation has become the fastest growing energy in the power system because of its advantages of clean use, environmental protection and large capacity. However, the long-distance transmission of wind power will lead to the severe voltage drop of the transmission lines, which seriously affects the voltage quality of power system operation. In view of this, the voltage stability of the wind farm becomes the main factor to restrict the development of wind power, and it is urgent to establish a perfect wind farm AVC control system. In this paper, the control strategy of AVC control system for wind farm was studied, and the optimal allocation method of reactive power compensation equipment and the control strategy of reactive power optimization in wind farm were also presented to ensure the balance of reactive power and the economy of operation in the wind farm. Firstly, the model of doubly fed induction generator (DFIG) was modeled, and the reactive power output limit of DFIG was derived based on its decoupling characteristic of PQ. The voltage distribution characteristics of the wind farm were discussed without consideration of the wind farm reactive power compensation equipment.Secondly, the optimal allocation method of reactive power compensation equipment in wind farm was studied. The probability distribution of wind speed submitted to Weibull distribution. According to this, the optimal allocation model of reactive power compensation equipment based on multi-scene analysis was established with the objective functions of minimizing the active power loss cost of the wind farm and the investment cost of reactive power compensation equipment. The differential evolution (DE) algorithm is used to solve the optimization problem. The MATLAB simulation results verified the effectiveness of the optimization model and solving method.Finally, the optimal control strategy of reactive power and voltage in the wind farm considering wind power forecasting information was proposed based on the optimal allocation of the wind farm reactive power compensation equipment. According to whether using the load forecasting information or not, the wind farm reactive power optimization was divided into basic control mode and real time processing mode, and the reactive power compensation equipment with different time characteristics were controlled. A case study of the Hui Teng Liang wind farm of Inner Mongolia was selected, and the modeling and simulation were based on matlab/matpower. The simulation results showed that the optimal control strategy of reactive power voltage of wind farm proposed in this paper could effectively suppress the voltage fluctuation in the variation of wind power output.