An Approach To Determine The Local Boundary Of Small Disturbances Voltage Stability Region With Wind Farm In Power Injection Space

As a form of renewable power, wind power is the most mature technology and developed rapidly in recent years. However, wind power is intermittent and non-schedulable while providing clean energy. These features will pose a negative effect on conventional power system. Also, wind farms will absorb considerable amount of reactive power from system while sending out active power, and due to the close revalence of voltage stability and reactive power, large-scale wind farms have certain influence on voltage stability.This thesis focuses on static voltage stability considered with large-scale wind farms, main work is as following:1. Current wind farm models used in power flow analysis are discussed and compared, and the model of asynchronous wind generator and doubly-fed wind generator used in this thesis is established respectively.2..Study the boundary of voltage stability region with wind farm in power injection space in depth.3. Power flow tracing and double dispatching are used to get the coherent generation that closely associated with the wind farm.4.. On those basis, a new approcach to determine the local boundaries of voltage stability region in injection space (IVSR) with wind farms is presented,which can be used for voltage stability analysis and online safety monitoring when the wind speed is difficult to predict.Firstly, Power flow tracing and double dispatching are firstly used to get the coherent generation that closely associated with the wind farm, in order to balance the fluctuations of power caused by the changes of wind speed.Further, the key generator nodes are gotten by using modal analysis isn order to achieve an effective dimension reduction .Finally, divided the power or wind speed interval of wind farms into several sub-intervals and combined with parallel computing, the local boundary of IVSR in next time can be gotten by the method of small disturbances. The method is finally validated by the system of New England 39-bus. It can be revealed that the method can exactly obtain the local boundary of IVSR at different wind speed and has a good application propect.