Multi-objective Reactive Power Optimization Of Power System With Wind Farm

With the development of economy,China's energy security and environmental problems can not be ignored anymore.As a green energy,wind power has brought a bright future for the domestic power industry.According to the 13 th Five-Year Plan of wind development,the investment in wind power will reach more than 700 billion during the period of "13th Five-Year".The large-scale development and utilization of wind power will have a great impact on the power system due to its randomness,fluctuation and intermittency.Therefore,analyzing the flow calculation of power system with wind farm,studying the multi-objective reactive power optimization algorithm and determining the strategy of reactive power optimization will be important for increasing the utilization rate of wind energy,improving the quality of voltage and guaranteeing the stability of the system.In this paper,based on the study of flow calculation of power system with wind farm,the PSO-NSGA-II algorithm is used to solve the multi-objective reactive power optimization problem.Firstly,the flow calculation of power system with wind farm is studied based on Newton-Raphson method and QV joint iteration model.In this paper the iterative methods of load flow calculation is discussed and the processing method of wind farm is analyzed after building the mathematical model and the power output model of asynchronous wind turbine.Secondly,multi-objective optimization method based on Pareto is proposed,which considering objective functions of active power loss,node voltage offset and static voltage stability margin.Because reactive power optimization is a nonlinear programming problem with multiple objectives,the optimization based on Pareto can obtain the scheme more suitable.Thirdly,the PSO-NSGA-II algorithm is proposed to get the Pareto optimal solution set of reactive power optimization.Based on NSGA-II algorithm,the idea of PSO algorithm is applied to improve the optimization ability and convergence speed.And the constrained optimization problem is solved by using the concept of constraint violation degree.Finally,the multi-objective reactive power optimization of IEEE-14 bus system which contained wind farm is solved by MATLAB programming.By comparing the results of several processing models of wind farm,it is verified that the QV jointiteration model can take into account both the speed and accuracy.The reactive power optimization results and evalutation indexes proved that the PSO-NSGA-II algorithm can effectively solve the multi-objective optimization problem and has a better global convergence.