Study On High Accuracy Figure Metrology Of Rotor Winding Inter-turn Short Circuit Fault In Turbine Generator

The rotor winding inter-turn short circuit is the common failure of the turbogenerator,and it poses a hazard to the stable operation of the turbo-generator and the power system.After the inter-turn short circuit occurs,the fault will change the internal electromagnetic field in the generator,resulting in the change of the parameters.Considering the saturation of the magnetic circuit,the distortion of the magnetic field and the cross-magnetization of the magnetic field,this thesis studied the accurate calculation of the parameters before and after the rotor winding inter-turn short circuit of the turbo-generator.The main work of this thesis are as follows.(1)With a QFSN-300-2-20 B turbo-generator as the research object,the electromagnetic field simulation model of the turbo-generator was established by the finite element method.This thesis linearized the nonlinear field by the freeze element permeability method,and improved the vector diagram of the steady-state operation of the turbo-generator.The method for calculating the synchronous reactance and the excitation current of turbo-generator was studied in this thesis by combining the finite element method with the analytical method.(2)Under rated condition,the influence of the number of turns and the fault locations on the parameters such as synchronous reactance,excitation current and noload electromotive force for rotor winding inter-turn short circuit was studied by the finite element method.This thesis analyzed the change trend of the parameter values before and after failure,and compared the relationship between the degree of the short-circuit fault of rotor turns and the change of the reactance,the excitation current and the no-load electromotive force.(3)The change trend of the excitation current,the synchronous reactance and the no-load electromotive force with the working conditions was analyzed.Considering the influence of nonlinear factors and improving the calculation method of parameters,the effect of high accuracy figure metrology of rotor winding inter-turn short circuit fault was realized on the basis of the original excitation current method.