Analysis And Diagnosis Of Large Synchronous Condenser Rotor Failure With Disease Operation

The main function of a synchronous condenser without mechanical load is to deliver reactive power to the grid and maintain the relative stability of the grid.During the "13th Five-Year Plan" period,China has gradually installed a new generation of large-capacity synchronous condenser on both ends of high-voltage DC transmission lines.The safe and reliable operation of the synchronous condenser is of great significance to improve the power quality and maintain the voltage stability of the grid.In this paper,we analyze in detail the magnetic field characteristics and vibration characteristics after the rotor winding short circuit and air gap static eccentricity fault,and propose a fault diagnosis method for the rotor of the synchronous condenser according to this characteristic.The main research results are as follows.(1)Taking a 300 Mvar dual water intercooled condenser as the object of study,ANSYS software is used to build a finite element model of the rotor winding in case of inter-turn short circuit and static eccentric fault,solve the air gap magnetic field distribution characteristics of the condenser after inter-turn short circuit and static eccentric fault,and use Maxwell’s stress tensor method to calculate the unbalanced magnetic pull on the rotor of the condenser after different types of faults;summarize The similarities and differences of the characteristic quantities of the condenser after inter-turn short-circuit fault and static eccentric fault are summarized.(2)Based on SIMULINK/ANSYS,we construct a coupled field-circuit-grid simulation model for high-voltage DC transmission with synchronous condenser,and study the change characteristics of air-gap magnetic field and unbalanced magnetic pull on rotor before and after phase change failure with rotor winding inter-turn short-circuit and static eccentric fault running condenser.(3)A multi-source information fusion-based fault diagnosis method is proposed for the synchronous condenser,using the finite element method to fuse and determine the fault characteristics before and after phase change failure of the synchronous condenser with turn-to-turn short circuit using D-S evidence theory,and improve the accuracy of turn-to-turn short circuit fault diagnosis using a model MJF-30-6.MJF-30-6 3-pole synchronous motor was used to verify the feasibility of this method.(4)proposed a kind of online monitoring program to determine the degree of air gap eccentricity failure by using the two-fold frequency vibration and vibration amplitude of the bearing seat after the eccentricity failure of the synchronous condenser.The vibration characteristics of the bearing housing after static eccentricity failure are derived,and the conclusion that static eccentricity will cause difrequency vibration of the condenser,and the difrequency vibration and vibration amplitude are used as the characteristic quantity to identify the degree of failure.The unbalanced electromagnetic force on the bearing housing after different degrees of eccentricity failure is simulated and verified.