Diagnosis of early turn-to-turn short-circuit faults of traction motor stators based on step excitation response
In order to realize reliable diagnosis of early faults of stator winding turn-to-turn short circuits of traction motors,a fault diagnosis method based on steady-state response current of step excitation was proposed in this study.Firstly,on the basis of a three-phase stator winding turn-to-turn short-circuit model of traction motors,a step excitation was applied to any two phases of the stator winding to derive the response current expressions in three cases,and a new fault characteristic component was proposed on the basis of the change characteristics of the steady-state value of the response current.Then,a simulation model of the faulty motor was established to analyze the impact of short-circuit resistance and fault severity on the response current,and to investigate the validity and reliability of the fault characteristic components for the diagnosis of early turn-to-turn short-circuit faults.Finally,an experimental platform was built to analyze the impact of turn-to-turn short-circuit faults on the fault characteristic components when the motor is inherently asymmetric.The simulation and experimental results show that the fault characteristic component can represent the early turn-to-turn short-circuit fault and its severity,and can filter out the impact of the inherent asymmetry of the motor.The diagnosis method based on the steady-state response current of step excitation is easy to operate and the results are highly reliable.This method holds great significance for the protection of the traction system and offers great value for engineering applications.
traction motorstator winding turn-to-turn short circuitfault diagnosisstep response
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