Study On The Control Strategy For Reactive Power And Voltage Of Wind Farms Cluster

With the rapidly development of wind power industry,the scale of wind farms is geetting larger and larger.It causes voltage flucations of the centralized point of common coupling(PCC)of wind farms cluster.Owing to reactive power regulation function,doubly fed induction generator(DFIG)is becoming more and more popular.There are few studies about optimizing the volatge and power loss in the control strategy for the reactive power and voltage of wind farms cluster.And the problem of DFIG operation life caused by the maximum reactive power needs to be studied at the same time.To solve the above problems,this thesis establishes the mathematical model of DFIG firstly.Based on this,the reactive power range of DFIG is analyzed.A control strategy for reactive power and voltage of wind farms cluster is propsed.The strategy has two modules,the calculator module and the allocation module.First,the required reactive power is estimated by the PCC voltage of the wind farms cluster;Second,the number of the generators participated in the reactive power allocation is computed by the bus voltage of the wind farms branch;Then,the reactive power of generators and compensation devices is calculated by the adjacent experiential particle swarm optimization(AEPSO).The simulation results show a better performance of the control strategy in respects of stabilizing the voltage of PCC,optimizing the wind farms and improving the convergence speed of the algorithm.But the optimization results,volatge and power loss of the wind farms,could be better.And some DFIGs provide reactive power at full capacity.To solve the above problems,a control strategy for reactive power and voltage of wind farms cluster based on the reactive power margin is also propsed.The strategy has three modules.First,the required reactive power of this time is estimated by the PCC voltage and the reactive power of last time;Second,the reactive power of each wind farm is computed by the reactive power margin;Third,the power loss and voltage deviation of the wind farm is optimazed and the reactive power of generators and compensation devices is calculated by the simplified adaptive artificial fish swarm algorithm(SAAFSA).The simulation results prove that this control strategy can improve the optimization resluts of the wind farms and avoid the DFIGs provide reactive power at full capacity.