Research On Reactive Power Compensation Strategy Of DFIG Wind Farm With SVG

The use of fossil fuels in production and life has a very serious impact on the environment.Fossil fuels are non renewable energy sources,and a large amount of use will also cause energy shortage.These problems have gradually attracted attention of scholars.Renewable energy is developing rapidly,and the development and utilization of wind energy is particularly fast.However,due to the randomness and intermittency of wind energy itself,with the rapid development of wind power,the grid capacity of wind power is increasing gradually,thus the impact on the stability of the power grid is growing,especially on the stability of the voltage.The problem of voltage stability is mainly the compensation of reactive power.Therefore,reactive power compensation is particularly important in wind power grid connected system.The grid connection models of different types of wind turbines are analyzed in this paper.The compensation characteristics and working principles of reactive power compensation devices are introduced.Through the comparison of a variety of wind turbines,the superiority of the widely used Doubly-Fed Induction Generator is highlighted,and through the analysis and comparison of a variety of reactive power compensator,the advantages of static var generator in reactive power compensation is highlighted.For reactive power compensation for wind power grid-connected systems,A reactive power coordinated control strategy between DFIGs and SVG is proposed.Both DFIG rotor-side converter and grid-side converter use double-closed-loop control.In the control of DFIG rotor-side converter,Power System Stabilizer is introduced to suppress low-frequency oscillation of the system.The control of SVG use direct current control.The reactive power demand of the system is distributed among the DFIGs and the SVG.First,DFIGs provide reactive power for the system,then SVG provide reactive power for the system.A DFIG wind farm in the north of China is built in the MATLAB/SIMULINK software platform,and the simulation and analysis of the system is carried out,the simulation results show that by comparing with the traditional constant power factor control mode,the superiority and feasibility of the proposed control strategy are verified according to the change of PCC voltage in the network.The voltage stability of PCC is improved,the reactive power of the DFIGs is fully utilized,the capacity configuration of SVG is reduced and the economy of the wind power grid connected system is improved.