The Study Of SVC Used For Wind Power System Voltage Stability Control

Development of new energy is taken into account due to energy crisis and environmental pollution, and wind power technology as the fastest growing clean energy is especially popular. In recent years, both the capacity of stand-alone wind turbine and the scale of wind farm construction are growing day by day. Besides China, many countries have made policies to 'promote the wind power. A variety of new problems, which have been brought by the proportion of wind power increasing, have become increasingly prominent in power grid. Random and intermittence of wind has more and more influence on the stability of power system.Based on the traditional static shunt reactive power compensation technology, SVC takes advantage of power electronic element to achieve fast compensation and continuous smooth adjustment, provide dynamic voltage support, and improve the operating performance of system. Ideal SVC has capacity to support the voltage of the node compensated to constant. According to the voltage deviation at the access point net of wind farm, SVC installed for the wind farm controls the reactive power needed for compensation to stabilize the node voltage of wind farm and reduce the effect of wind power fluctuation on power grid. The voltage fluctuation results from the output power change which is led by the changing wind speed, and TCR+FC is adapted to stabilize the voltage fluctuation in this paper.First of all, application and status of wind power technology has been summarized, the variable speed constant frequency wind power generation system is introduced, and the mathematical models of wind speed, wind turbine, and double-fed motor are presented. With the double-fed variable speed constant frequency wind power generation system as the object of study, the influence on grid brought by grid-connected wind power plants is analyzed.Secondly, the basic principle, composition and classification of SVC are introduced, especially the principle of SVC control system for voltage stability. Then, the simulation model of TCR+FC type SVC is built in MATLAB/Simulink. In the end, using Matlab Simulink, the simulation platform of SVC applied to wind power system is built. Through simulation, it is proved that SVC is capable of suppressing fluctuation of power grid caused by the output power of double-fed wind power generation system, and stabilizing the grid voltage.