Research On The Optimal Control For Reactive Power In Wind Farms Based On Genetic Algorithm

Large-scale wind power integration will cause bad influence to power systems, so it is necessary to take reactive power compensation measures to optimize the power flow distribution, reduce the power losses and improve the voltage stability of wind farms. The optimal control of planning and operation for reactive power in wind farms are well researched in this paper based on the improved genetic algorithm (IGA). The optimal planning model of reactive power, which aims to minimize the costs of expectation value of yearly active power losses and annual-converted reactive power compensation device (RPCD) investments in wind farms, is established based on scenario analysis and expectation value planning, with the consideration of the affection of uncertain factors of active power output of wind farms. The optimal operation model of reactive power in wind farms, which aims to minimize the active power losses in wind farms, is established with the consideration of two reactive power supplies which are DFIGs and RPCDs. A dynamic optimal control strategy for reactive power in wind farms is proposed based on the strategy thought of "fix-place and quantitative optimal control" and wind farm active power output plan curve. The strategy includes three function modules which are SCADA, WFDPM and WFCM. Finally, the actual network-connected wind farm model is established based on DIgSILENT/PowerFactory, in which the reactive power planning optimization model and three reactive power operation optimization models are established and solved by IGA. The calculation results illustrate the best installation place and capacity of RPCD in wind farms, and the optimal compensation capacity for four typical scenarios of each reactive power compensation plan. In addition, the effectiveness of optimal control strategy for reactive power in wind farms is validated based on day-ahead active power output plan curve, and the results demonstrate that the reactive power control strategy proposed in this paper can effectively reduce the active power losses of wind farm and realize the optimal power flow.