Transient Stability Analysis Of Power System Including Wind Power

With the increasing penetration of wind power, it has become an urgent problem to study the transient stability of power system including wind power. Different with conventional generations, for wind turbines, most of which are asynchronous generators, there is no angle stability or conventional synchronous stability. The effect of wind turbines or wind farms on power system transient stability is reflected by conventional synchronous generators in the actual power system. By far, simulation method is often used to analyze the transient stability of power system including wind power, and the curve of synchronous generator’s power angle and the critical clearing time are usually used as criteria. This paper mainly stretches the research from aspects of transient stability analysis method of power system including wind power, improvement and application of analysis methods etc. The main work sums up as follows:(a) Firstly, the wind turbine model is built, and the mathematical equation and control block diagram of wind turbine is deduced. Further, lumped parameter modeling approach is used to develop wind farm model. In detail, equivalent power loss principle is used to simplify the collection system of wind farm, and the capacity weighting method is used to calculate parameters of the equivalent model.(b) Assuming that the instability mode of the system is a two-machine mode, and that the effect of wind farms on the power system is the most serious, firstly, the motion equation and power angle characteristic of the power system including wind farms are derived, treating the mechanical power and electromagnetic power of wind farms as part of system equivalent mechanical power; Secondly, the variation of system equivalent mechanical power is studied in the simulation analysis of the single machine infinite system including a wind farm, and then the extended equal area criterion used for the transient stability analysis of the power system including wind farms is derived. CIGRE B4-39test system is adopted to test and verify the effectiveness of the proposed method.(c) The sensitivity indicators of wind turbine control parameters affecting the transient characteristics of wind turbine are proposed, and the key parameters are determined. Then different control modes of wind turbine are achieved with the rational allocation of key parameters,and the influence of the control characteristics of wind turbine on system equivalent mechanical power is analyzed. Further, at the same control characteristics of wind turbine, the influence of the output of wind farm on system equivalent mechanical power is also analyzed, and the variation pattern of system equivalent mechanical power during fault is summarized. The extended equal area criterion used for the transient stability analysis of the power system including wind farms is improved further.