Research On Reactive Power Optimization Control Strategy On Regional Power Grids Containing Wind Farms

With the continuous development of power network technology and the rapid development of large power grids,the requirements of power grid operation on power quality have become more and more strict.The reactive power optimization of the power system is to minimize the net loss and reduce the cost of the maintenance of the power grid to obtain more economic benefits in the case of guaranteeing the qualified voltage.With the rapid development of wind power technology,a large number of wind turbines are connected to the power system.Wind power generation can improve the economy of the operation of the regional power grid and reduce the emission of pollutants,and bring positive impact on the operation of power grids.However,due to the uncertainty of wind power generation,this kind of fluctuation will also cause the decrease of the voltage qualification rate.This paper does the following work on the basis of the wind farm access to the regional power grid:Firstly,the purpose and significance of reactive voltage control in regional grids containing wind farms are introduced,and the comparison of reactive power optimization technology in China and abroad,and the advantages and disadvantages of corresponding optimization techniques are briefly summarizedSecondly,the difficulty and necessity of reactive power optimization in regional power grid with wind farms are introduced in detail.Then the basic principle of reactive power compensation in reactive power optimization is analyzed.On the basis of the structure characteristics of regional power grid,the basic principles of reactive power optimization control are obtained.At the same time,the voltage quality,network loss and reactive power equipment are guaranteed.Four control strategies of reactive power optimization are introduced based on the restriction of switching times.Thirdly,the grid model and mathematical model of the doubly fed wind turbine are introduced,and the probability model of the output power of the wind turbine is calculated according to the output power characteristics of the wind turbine.The probability model of wind speed is studied,and the Point Estimation Method of wind power is put forward.The advantages and disadvantages of the whole scene model and the point estimation method are compared.Meanwhile,based on the monthly mean wind speed data of Suiping Jianshan,the model of wind farm based on point estimation method is obtained.Finally,the load model of regional power grid is established.Prepare for the later part of the simulation.Finally,propose a new two-stage reactive power control strategy,and give control structure,control flow and mathematical model of reactive power optimization.Under the wind power model based on point estimation method,an improved IEEE33 node model was established in the DIgSILENT/PowerFactory software for simulation analysis.The global control and two-level coordinated control of the wind farm were selected,and the two-level control under the Monte Carlo method was selected.Performance simulation and global control,common scenes in actual operation are compared and simulated.Simulation results verify the rationality and effectiveness of wind power model and two-level reactive power coordination control.