Research On Fault Operation Of Twelve-phase Rectifier Generator System

The high requirement of power supply in the application field of 12-phase rectifier generator system makes the study of system fault operation status an indispensable part.In order to analyze the characteristics of 12-phase rectifier generator system during fault operation,a field-circuit coupling simulation model is established based on finite element method.The model couples magnetic field and rectifier circuit to simulate,and is suitable for the study of various faults of the system.It has the characteristics of high accuracy,few calculation parameters,low difficulty in solving,et al.In order to prove the correctness of the model,the model is used to analyze the no-load and normal operation of the system.The simulation results are basically consistent with the experimental results,which proves that the model is correct and reasonable.In order to explore the operation characteristics of rectifier system when some faults occur,three kinds of faults such as diode open circuit,diode short circuit and rectifier bridge missing are studied by using the model.By analyzing the waveforms,numerical values of load voltage and phase current under different fault conditions,the variation characteristics of each electrical quantity are obtained.The characteristics of load voltage and phase current change in the diode open circuit and rectifier bridge missing indicate that the system running with fault operation is feasible,and the characteristics of phase current change in the diode short circuit can guide the design of system protection strategy.Taking generator stator winding inter-turn short circuit and inter-phase short circuit as examples,the internal fault of generator is studied.In order to make the model suitable for the analysis of internal faults of generators,the model is modified to simulate various winding faults.The modified model is used to study the stator winding inter-turn short circuit and inter-phase short circuit faults.By analyzing the waveforms and numerical values of the system load voltage,phase current and short circuit branch current under the two fault states,the variation characteristics of each electrical quantity are obtained.It is found that the variation characteristics of each electrical quantity of stator winding in turn-to-turn short circuit are similar to that in phase-to-phase short circuit.The research work has reference significance for the design of system protection strategy.In the research process,the simulation results of various faults are compared by using the built prototype experimental platform,which illustrates the accuracy of the analysis.This thesis provides a feasible method for the study of the rectifier faults and internal faults of the 12-phase rectifier generator system.