Study On Frequency Regulation Strategy Of Wind Turbines In Power Systems

In order to curb the frequency regulation problems caused by large scale wind power used in power grid, the most commonly used method is to use the frequency regulation capability of conventional generators. But it is difficult to meet and ensure the quality of power grid frequency only by conventional generators, when the scale of wind power reaches a large degree. So as to further make full use of wind energy and promote the development of wind power, it is necessary to fully tap potential ability of doubly-fed induction generator(DFIG) type of wind turbine which involved in power system frequency regulation. This research will have a good theoretical and practical significance on the effective used of DFIG and has obtained the following results:(1) Establish the linear model of fast power control peculiarity of DFIG, and analyze the active power control peculiarity of DFIG. According to peculiarity of how the rotor side converter to control the active power by controlling the rotor current component, this paper deduces the mathematical model.(2) This paper proposes a method about the wind speed segment classification for DFIG to participate in frequency regulation. According to give the appropriate division of wind speed, let DFIG to undertake the different frequency regulation mission in different wind speed segment, and also have good running characteristics.For the further theoretical basis is provided for effective control of DFIG.(3) This paper proposes a strategy about capacity allocation of frequency regulation between each wind farm in one regional. And analysis the problem that the wind turbine mechanical wear result of adjusting the pitch angle frequently when DFIGs need to deloading operate. In order to improve the strategy about capacity allocation of frequency regulation and make the DFIGs in a good operation condition, DFIGs need to reduce the adjustment of pitch angle as much as possible,and do not have large influence on the effect of frequency regulation when DFIGs have to undertake the frequency regulation mission.(4) Redesign the load frequency control system in a interconnected power system after considering the model of DFIG. This paper justifies the power system is an asymptotic stability system, when the system has parameter uncertainty exists and under large load changes. On the basis of the designed control system, analyze the load frequency control method of power system with wind power.