Study On Influence Of Wind Power Integration On System Stability And Its Control Strategy

With the rapid development of the economy,the energy crisis and environmental degradation have threatened the development and security of human society.Hence,all countries are actively developing and utilizing new energy.As a kind of renewable and clean energy,wind energy is not only rich,but also easy to develop and pollution-free.Therefore,wind power has been rapidly developed in recent years,and the scale and capacity of the wind power have increased year by year.With the increase of grid-connected capacity,the intermittent and random nature of wind power generation has a huge impact on the stability of power system voltage and power angle.Based on this problem,this paper has conducted in-depth research on the stability of wind power access systems.The doubly-fed wind turbine is currently the most widely used wind turbine.It can independently control the excitation current of the rotor to achieve decoupling control of active and reactive power.First,this paper introduces in detail the working principle and model structure of the doubly-fed wind power generator,including the prime mover and controller module.The corresponding doubly-fed wind turbine model was built under PSCAD/EMTDC to construct a single-machine infinite system and the accuracy of the model was verified by simulation experiments.Secondly,the equivalent circuit of the doubly-fed wind turbine is derived.The factors affecting the system voltage after wind power grid connection are theoretically analyzed.The compensation measures such as shunt capacitor compensator and series capacitor compensator are proposed.The rationality of improved performance is verified by simulation.The effect of the series compensation is better than shunt compensation,its recovery of voltage after fault is better,but the control process of series capacitor compensation mode is more complicated.Then based on the power equation of the doubly-fed wind turbine,it is proved that the external characteristics can be characterized by shunt impedance.On this basis,the effects of grid-connected capacity,adjustment of the synchronous machine output,grid-connected position and other factors on the stability of the power angle are further studied and we get the corresponding conclusions.As the scale of wind power increases,the static stability and transient stability first improve and then deteriorate.As the grid-connected point is far away from the advanced synchronous cluster,the static stability and transient stability are continuously improved.The more the capacity of the advanced group synchronous unit has,the more conducive to static system stability and transient stability.From the system perspective the conclusions obtained help to understand the influence of grid-connected capacity,synchronous machine output adjustment and grid-connected position after wind power access,which provides an analysis method for analyzing the angular stability.Finally,the paper analyzes the stability of the wind power access system and proposes related solutions.