Method for determining position of turn-to-turn short circuit failure of excitation winding of motor

Abstract

Disclosed is a method for determining the position of a turn-to-turn short circuit failure of an excitation winding of a motor. The method comprises the steps of acquiring the current signal of one branch of a stator winding during operation of the synchronous motor and conducting fast Fourier transform on the signal to obtain each harmonic amplitude of the signal, finding a stator branch harmonic current which serves as a fault feature harmonic wave and is caused by the turn-to-turn short circuit of the exciting winding from the harmonic amplitudes of the signal and calculating the ratio between the different fault feature harmonic wave current amplitudes, and finally comparing the ratio with a ratio obtained in advance through simulation to find the failure corresponding to the ratio so that a coil where the turn-to-turn short circuit occurs can be determined. According to the method, positioning of the turn-to-turn short circuit failure of the excitation winding can be achieved without installing a detection coil in a cavity of a motor stator, positioning accuracy is high, and application range is wide. The method can help maintenance staff position the turn-to-turn short circuit failure of the excitation winding accurately and creates favorable conditions for eliminating potential safety hazards in time and preventing the short circuit failure from spreading.

Description

technical field [0001] The invention relates to a method capable of determining the inter-turn short-circuit fault location of an excitation coil of a synchronous motor, which belongs to the technical field of motors. Background technique [0002] Synchronous motors are widely used in power systems, industrial production and other fields. Turn-to-turn short-circuit faults of excitation coils are frequent faults of synchronous motors. There are two types of faults: static inter-turn short-circuit and dynamic inter-turn short-circuit. [0003] The static turn-to-turn short circuit does not change with the rotor rotation state and operating conditions, and can be detected during shutdown. There are relatively mature methods for detecting and locating static inter-turn short-circuit faults of large synchronous motors. Generally, routine experiments, such as AC impedance and power loss tests based on rotor windings, rotor winding pole balance tests, and RSO repetitive pulse tests...

AI Technical Summary

Problems solved by technology

However, at present, most motors are not equipped with detection coils when they leave the factory. It is very difficult to install the coils on motors that have already been put into operation, and it is also difficult to be accepted by users, which limits the application range of this method.

[0010] In short, although the detection of inter-turn short-circuit faults of synchronous motor excitation windings has been paid great attention at home and abroad, there are still some difficulties in using various existing methods to locate inter-turn short-circuit coils, especially the location of dynamic inter-turn short-circuits.

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