Power System Security And Stability Control Research Including Wind Farms

Faced with the crises of energy shortage and ecological damage, develop and utilize the new and renewable energy has become the key research problem in various countries. As one form of utilization of new energy, the wind power has already begun in-depth study by the world. Due to the large variation of wind speed, the out put of the wind farm also changed greatly, thus resulting in the safety and stability of power systems became deteriorate with the increase installed capacity of the wind farms. Take effective control strategy to power system with wind power is the key to security large-scale wind power into grid.This article is mainly from two aspects which is voltage stability and Angle stability to research the control strategy of wind power systems with double-fed induction generator(DFIG). The main contents are:Detailed introduced the working principle of DFIG, established the wind models in different coordinate systems and also established the model of wind farm and the model of wind power system with DFIG. Simulation analysis results show that the variable-speed operation characteristics of DFIG and the pitch angle control system can be optimized the output power, which made the generator stabled under different wind speeds. While the low-voltage ride-through capability of wind power system was introduced and analyzed.When make the voltage stability analysis of power system with wind power, the wind farm can be seen as the special load nodes which could provide active power and the reactive power could be dynamically adjusted. Using reactive power compensation strategy to prevent the voltage instability of wind farms, application of genetic algorithm combined flow repeatedly calculated the optimal reactive compensation capacity of wind farms. If only using shunt capacitor banks to compensate the reactive power of wind farms, because of its packet switching result in the compensation capacity can only select segmentally, can not achieved reactive power compensation smoothly, so proposed a jointed compensation control strategy which is using STATCOM and capacitor bank, which improve the compensation effect significantly.Through analyzing the operation characteristics of DFIG during steady state, combined with the angle operating characteristics of synchronous generator, then defined the angle of DFIG. By analyzing and comparing the power system which include two synchronous generators and the power system which with a DFIG replace a synchronous, among then, DFIG and synchronous generators has the same capacity, then studied the angle operation characteristics of DFIG. Because of fault disturbances, the angle of DFIG would become large, so proposed using the alternate coordinate system during the fault, and improve the traditional double-loop control of DFIG then formed the additional angle control strategy, finally, using an example of the simulation to validate the proposed strategy.