Research On Disturbance Analysis Considering Excitation System And Generator Nonlinearity

As an important component of the power system,the nonlinear effect of the generator affects its static stability and transient stability to varying degrees.Especially for different excitation system model under the influence of the single-generator system disturbance process is more complex.In this thesis,the static stability of the generator and the analysis of the typical disturbance process are analyzed,which takes into account the different excitation system models and the nonlinear effect of the generator.It provides a reasonable reference and basis for the simulation study of the power system.The main results are as follows:1)The method of calculating the power angle of the generator based on the finite element method is presented,and the static stability of the synchronous generator under the combined action of nonlinearity and excitation regulation is studied.The results show that the static stability limit of the generator is increased when the excitation regulator is applied,but the static stability limit should be reduced if the synchronous generator saturation is also considered.2)Based on the practical model of the generator,the generator linearization model is obtained by linearizing the generator operating point.The static stability criterion considering the non-linear effect of the generator is derived by using the saturation parameter of the linear model.It is shown that the limit power of the generator appears in the power angle after installation of the excitation regulator,and enters the artificial stability zone,which increases the static stability The range of the area.Considering the nonlinear effect of the generator,the range of the static stability region will be reduced.3)Considering the interaction of generator PID dynamic corrector and power system stabilizer,the influence of the nonlinear effect of generator on the simulation results of typical small disturbance and large disturbance is compared and analyzed.The results show that the oscillation frequency of the small disturbance perturbation curve decreases and the damping ratio increases with the nonlinear effect of the generator.For large disturbances,the oscillation amplitude of the angular velocity increases,and the difference of the power angle curve is obvious.4)The discretization equations of different excitation system models are established,and the coupled time-step finite element model of the generator-road-net is proposed.The results show that the excitation system based on the dynamic corrector has the advantages of obvious control effect and convenient adjustment.At the same time,compared with the simulation results of the single machine infinite system of the single generator with infinite effect of the different excitation system and the additional power system stabilizer,After the additional power system stabilizer PSS,has the very good effect to the system low frequency oscillation suppression.