Turn-to-turn short circuit fault diagnosis method for rotor winding of brushless excitation generator

Abstract

The invention discloses a turn-to-turn short circuit fault diagnosis method for a rotor winding of a brushless excitation generator. The turn-to-turn short circuit fault diagnosis method comprises the steps that the theoretical reactive power value Q of the brushless excitation generator under the normal state is reversely calculated, the reactive power relative deviation a% of the measured reactive power value Q' and the theoretical reactive power value Q of the brushless excitation generator is calculated, the reactive power relative deviation a% and the preset threshold value are compared, and whether a turn-to-turn short circuit fault of the rotor winding occurs or not is judged. By means of the turn-to-turn short circuit fault diagnosis method, the accuracy on the aspect of the detection of the turn-to-turn short circuit of the rotor winding of the brushless excitation generator is improved. The defect that excitation currents cannot be detected when an excitation current method is adopted for the brushless excitation generator is overcome, faults under any working condition can be detected, the size is judged, and the severity degree of the short circuit fault can be directly reflected. New mentoring points do not need to be increased, operation is easy and convenient, sensitivity is high, and cost is saved.

Description

Technical field [0001] The invention relates to a method for diagnosing short circuit faults of generator rotor windings, in particular to a method for diagnosing short circuit faults of rotor windings of brushless excitation generators, belonging to the technical field of generator fault diagnosis. Background technique [0002] At present, the methods for online detection of short circuit faults in rotor windings mainly include detection coil method, excitation current method and detection method based on rotor fundamental frequency vibration. [0003] The detection coil method differentiates the rotating magnetic field in the air gap of the stator core of the generator, and then analyzes the differentiated waveform of the signal to diagnose whether the rotor winding has an inter-turn short-circuit fault and the location of the fault slot. However, this method is only suitable for diagnosing hidden pole motors with distributed windings and high monitoring reliability can be obtain...

AI Technical Summary

Problems solved by technology

However, this method is only suitable for diagnosing hidden pole motors with distributed windings and can only obtain high monitoring reliability when the motor is under no load. When the motor is running with load, the detection effect is not obvious and the detection accuracy is poor.

[0004] The excitation current method is to monitor the short-circuit fault of the rotor according to the change of the excitation current before and after the short-circuit fault, but the excitation current of the brushless excitation system is unmeasurable, and this method is not suitable for the brushless excitation generator

[0005] The detection method based on the fundamental frequency vibration of the motor rotor is to detect the fault by analyzing the vibration signal of the rotor. However, the rotor vibration is the result of electromechanical cross-action, including the influence of the initial state such as mass imbalance and dynamic eccentricity, which makes the fault after the short circuit occurs. The fundamental frequency vibration of the motor may still be in the normal range and the fault cannot be detected

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