Method for detecting fault of rotating diode

Abstract

The invention discloses a method for detecting the fault of rotating diodes, which is characterized in that whether the rotating diode is at fault or not is judged by detecting specific value of the effective values of a first, a second, a third, a fourth, a fifth and a sixth subharmonic and the effective value of a twenty second subharmonic of exciting winding current of an exciter; when the specific value of the sum of the effective values of the first, the second, the third, the fourth, the fifth and the sixth subharmonic and the effective value of the twenty second subharmonic is less than0.1, the rotating diode is in normal operation, and when the specific value is more than 0.1, the rotating diode is at fault; when the specific value of the sum of the effective value of the first, the third and the fifth subharmonic and the effective value of the twenty second subharmonic is more than 50, the rotating diode has arm short fault, and when the specific value is less than 10 and more than 1, the rotating diode is in one phase open circuit, when the specific value is more than 10, the rotating diode is in multi-phase open circuit. The fault judging method of rotating diode of theinvention provides accurate and suitable control strategy for a generator when the rotating diode is at fault, and ensures that excitation system and the generator is in normal and safe operation.

Description

technical field [0001] The invention relates to a method for detecting and judging a rotating diode fault and a device using the method. Background technique [0002] The correct judgment of the fault of the rotating diode in the brushless excitation generator is very important for the safe operation of the generator and the rotating diode. At present, there are two main conventional methods for judging the fault of rotating diodes: [1，2] and pulse counting method [3，4] . The sudden change method usually detects the influence of the sudden change of the current of the faulty rotating diode on the magnetic flux of the motor core, detects the sudden change of the magnetic flux of the iron core, and then judges the fault of the rotating diode. This method has a small scope of application. For multi-phase rectification Due to the large number of phases of the rotating diode, when a certain phase fails, it has little influence on the magnetic flux of the motor iron core, and i...

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Problems solved by technology

The sudden change method usually detects the influence of the sudden change of the current of the faulty rotating diode on the magnetic flux of the motor core, detects the sudden change of the magnetic flux of the iron core, and then judges the fault of the rotating diode. This method has a small scope of application. For multi-phase rectification Due to the large number of phases of the rotating diode, when a certain phase fails, it has little influence on the magnetic flux of the motor iron core, and it is usually impossible to distinguish the magnetic flux change caused by the fault condition from the magnetic flux change caused by the normal adjustment of the excitation current, so that it cannot Correctly judge the fault of the rotating diode; the pulse counting method adopts installing an inductor on the motor base, and when the rotating diode branch has current flowing through the inductor and rotates through the inductor, a pulse waveform is induced in the inductor, and the pulses of the inductor are counted. Therefore, it can be judged that there is no current flowing after the fault of the rotating diode, because the stability of the sensor is poor, including the sensor being displaced by collision, resulting in inaccurate measurement, or the sensor (Hall device, etc.) itself is polluted by oil and dust to cause signal Distortion, etc., so the method has a high false action rate or rejection rate

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