Stochastic Interval Stability Analysis Of Wind Turbine With Small Disturbance

Due to the limitations of environmental,technical and information conditions,especially the random power fluctuations generated in the process of wind power generation,some parameter values of the wind power system are uncertain,which brings challenges to the study of the operation stability and safety of the power system.In order to study the impact of uncertain factors on the stability of the power system,this paper mainly compares the characteristics of different shaft model of the asynchronous wind turbine,applies the relevant theories of interval dynamical system stability and stochastic differential equation to derive the stability criterions of the system.And the validity of the result is verified by numerical simulation.(1)The shaft of asynchronous wind turbine is analyzed based on the equivalent lumped mass method.By comparing the two-mass shaft model,the three-mass shaft model and the five-mass shaft model of the asynchronous wind turbine,the five-mass shaft model is selected,combine the asynchronous generator model,the model is reduced by mathematical method,taking into account the influence of the uncertain parameters in the model and random small excitation,an interval model of asynchronous wind turbine and a stochastic interval model of asynchronous wind turbine are established.(2)For the interval model and stochastic interval model of asynchronous wind turbine,the stability criterions of the system is obtained by using Gersgorin disk theorem,Lyapunov function and other tools,the interval stability theorem and stochastic interval stability theorem are given,and the single-machine infinity system(OMIB)is used as an example to verify the conclusion.(3)Further study the stability of the stochastic interval model of the asynchronous wind turbine,use the matrix inequality,Ito integral and other tools to obtain the criterions of mean stability and mean square stability of the model,and give the bounds of the mean and the mean square stability of the system.This paper provides reference for further research on the stability of wind power system.