Study On Optimization Of Doubly-fed Wind Farm Adaptive Voltage Control System

Due to the volatility and intermittent nature of wind energy,when the active power output of the wind turbine generator is relatively large,the demand for reactive power of the system will increase,resulting in fluctuation of the grid-connected point voltage,and even exceeding the specified operating range.It has an adverse effect on the stable operation of the power system.Therefore,it is very necessary to study the control strategy of the grid-connected point voltage of the wind farm to reduce the voltage fluctuation.Firstly,the mathematical model of doubly-fed wind turbine was established,and the DIgSILENT simulation platform was used to simulate the grid-connected system of doubly-fed wind farm.The change of grid-connected point voltage with the wind speed of the wind farm was analyzed.Then,the voltage equation of the doubly-fed wind farm grid-connected point is deduced,and the vector control strategy of the doubly-fed wind turbine grid-connected system is theoretically analyzed.An improved adaptive voltage control(AVC)strategy is proposed and verified by simulation.It is not enough to rely solely on the reactive power of the wind farm itself to adjust the grid-connected point voltage,because the wind farm itself has the disadvantages of slow response,in addition to the lack of reactive power output.Therefore,it is necessary to use the reactive power compensation equipment to regulate the voltage of the grid-connected point.A simulation model is built and verified by simulation.The results show that the reactive power compensation equipment is used for coordinated control and the voltage fluctuation of the grid-connected point is better improved.