| With the rapid development of large-scale interconnected power systems in China, the stability becomes one of the most important factors effecting the inter-connected bulk power grids. And the weak or minus damping within a region or between different regions of bulk power grids are the most attracting. With the increasing capacity of wind power generation, the influences of the wind power on the small signal stability and damping characteristics of inter-connected power systems have become an important issue of concern. According to the actual condition of Jiangsu power grid, this paper analyses the small signal stability of power systems connected doubly fed induction generators (DFIG) and permanent magnetism synchronous generators (PMSG) comprehensively. Based on the PSD-BPA simulation software, the influences of different connecting voltage classes, methods and locations on damping characteristics of Jiangsu power grid are analyzed, and the suggestions on the selection of connecting method of large-scale wind farm are given. The main contents of this thesis include:(1) The dynamic models of wind generation system are established. The structure of the mathematic models of wind generation system is provided, including the control systems. A testing system containing wind farms and Jiangsu power grid are constructed in BPA.(2) The impact of high penetration of grid-connected wind farms on power system small signal stability is researched. The impacts of grid-connection of wind power generators in different types on damping characteristics of power grid under different wind power penetration are given respectively. Comparative analysis of damping characteristics is performed based on the control mechanism of wind power generation.(3) The impact of wind farms on the low-frequency oscillation characteristic of Jiangsu power grid is studied. By use of eigenvalue analysis, the impacts of grid-connected DFIG on damping characteristics of power system under different connecting voltage classes, methods and access points are researched in detail. Finally, some connecting methods conducive to the oscillation modes are improved by analysis of sensitive factors affecting damping characteristics. |
