Impacts Of Wind Power Uncertainties On Power System Power Flow And Transient Stability Analysis

Energy crisis and environmental problems are the two highlight issues in present social development. The large-scale development of renewable energy resources to large extent alleviates the crisis brought by the two issues. It should be noted that wind power generation has become one of the most mature and profitable renewable energy generating technologies. When the large-scale wind power is integrated into power grid, it will lead to great impacts on the existing power system secure and stable operation, especially on power flow and transient stability due to the existence of fluctuation and intermittency of wind power as well as stochastic load fluctuation, output variation of conventional synchronous generators, faults, etc. The corresponding studies on power system security and stability issues incorporating intermittent wind generation bear important academic and practical meanings.In this thesis, the current research status in probabilistic load flow and transient stability of power system incorporating wind power uncertainties is summarized based on a comprehensive literature review. From the points of probability and stochastic characteristics of wind speed, the impacts of large-scale wind farm of doubly-fed induction generator (DFIG) type integration on power flow and transient stability are studied elaborately. The main achievements are as follow.The three-point estimate based method is applied to implement the solution of probabilistic load flow incorporating wind farm of DFIG type. The stochastic models of wind farm, synchronous generator and load are built to study the impacts of wind power on probabilistic distributions of node voltage and branch power flow by applying point estimate technique before and after wind farm integration. The comparative analysis is done as well.Furthermore, the impacts of wind power integration on transient stability of power system are studied further. The dynamic model of DFIG and the stochastic model of fault are built firstly. Then the IEEE10-gen-39-bus test system is employed to conduct the analysis involving the calculation of transient stability probability and the impacts of wind power output changes on transient stability by applying Monte Carlo method. On the basis, the impacts of wind farm penetration level on transient stability are studied further. Some significant and meaningful conclusions and comments are drawn.