Stability Analysis Of Grid-Connected Wind Power Generation

As the development of new energy sources continues to increase,the share of wind power in the power energy structure is gradually increasing.However,due to its high randomness and strong uncertainty,it has a great impact on the operation of traditional power systems,especially the wind power is connected to the grid through the converter,which isolates the inertia of the machine end and reduces the inertia of the power system.This brings about system stability problems,as well as the stability problem of the wind turbine’s own grid connection.In recent years,the problem of broadband oscillation caused by grid connection of new energy in domestic and foreign power systems has occurred from time to time.Therefore,the problem of stable operation of wind power grid connection has become a research hotspot.At present,wind power grid connection stability research is mostly based on small signal analysis methods,and its models mostly use conventional control methods,rarely considering the effect of controller parameter changes on system stability under different control methods;based on large disturbances under grid failure Stability analysis and nonlinear analysis are also few.Therefore,this paper draws on the electromagnetic power angle model of the full-power wind power gridconnected system introduced by the singular perturbation principle and dominated by the phaselocked control loop to carry out stability analysis.The main research work is as follows:(1)Summarize the research status of wind power grid-connected stability at home and abroad,establish the mathematical model and simulation model of full-power wind turbine,and carry out simulation verification under different wind speed conditions.(2)Adopt the principle of singular perturbation to obtain the electromagnetic power angle model of the full-power wind turbine under the phase-locked loop control time scale.According to Lyapunov’s first method,the model is linearized to obtain the corresponding state equation group Then,the stability of the system is analyzed by the distribution of the system eigenvalues in the complex plane.Mainly analyzes the influence of PLL parameters on the stability of full-power wind turbine and its stable boundary conditions,and the correctness of the conclusion is verified through simulation.(3)For the large disturbance problem caused by the short circuit fault of the power system,the electromagnetic stability model of the wind power grid connection system is used to analyze the transient stability of the simple wind turbine grid connection system.The limit cut-off time to keep the system stable was derived and verified by simulation.(4)A chaotic model of a simple stand-alone wind power system is established,and the amplitude and frequency boundary conditions of the chaotic behavior caused by periodic disturbances are analyzed.The relationship between chaotic boundary conditions and internal parameters of the unit is obtained,and the correctness of the conclusion is verified through simulation.