Analysis And Detection Of Stator Core Faults Of Large Motors

Short-circuit faults between the stator core pieces will seriously affect the safe and stable operation of the motor.Judging the stator core according to the change of the electrical quantity of the motor after the short circuit fault occurs is a very important method to prevent safety hazards during operation and ensure normal operation.Therefore,in this thesis,the model YR630-12/1430 winding asynchronous motor is taken as the research object,and the short-circuit fault between the stator core pieces is analyzed in detail.This thesis first analyzes in detail the causes and characteristics of inter-chip short-circuit faults.According to the basic principle of the homogenization method,the equivalent conductance and magnetic permeability of non-fault regions and the equivalent of inter-chip short-circuit fault regions are calculated and analyzed respectively.Conductivity and magnetic permeability,and based on the basic theory of electromagnetic field,taking YR630-12/1430 winding asynchronous motor as the research object,a three-dimensional eddy current field finite element analysis model is established,and the stator core under different fault conditions is simulated and calculated,analysis of finite element results.Secondly,an analytical calculation method for the electrical parameters of the fault area is proposed.Based on the skin effect of the alternating magnetic field in the silicon steel sheet,the analytical formula and complex power expression of the magnetic field of the silicon steel sheet are deduced,and the induced voltage of the single silicon steel sheet is obtained;and the equivalent circuits of the single silicon steel sheet are established separately.Equivalent circuit of initial fault and complete fault area;calculate relevant electric quantity parameters according to the equivalent circuit of fault domain,and quantitatively analyze the influence of the number of fault pieces on electric quantity parameters of fault area;the comparison between the finite element simulation results and the analytical calculation results.Finally,according to the principle and composition of the stator core short-circuit fault detection system,the excitation voltage required for the offline test system is calculated and analyzed,and an experimental platform for short-circuit fault detection between the stator cores is set up.The experimental results are compared with the analytical calculation results to further analysis the failure phenomenon.