Device and method for detecting turn-to-turn insulation failure of rotor winding of generator

Abstract

The invention discloses a device and a method for detecting a turn-to-turn insulation failure of a rotor winding of a generator. The detection device comprises a signal generator and a digital oscilloscope which are connected to two ends of the rotor winding respectively. Excitation signals are applied to one end of the rotor winding by using the signal generator, and response signals are outputted at the other end of the rotor winding. The response signals are received and displayed by using the digital oscilloscope, and the excitation signals and the response signals are recorded and stored by using the digital oscilloscope at the same time. Determining whether a rotor winding insulation failure exists by comparing the response signals outputted from the two ends of the rotor winding which are recorded and stored by using the digital oscilloscope. According to the invention, generator rotor insulation failure detection can be performed at project site, problems in the rotor turn-to-turn short circuit failure detection in generator maintenance at the project site are solved, and the device and the method can also be applied to rotor winding insulation detection in motor manufacturing phase at the same time.

Description

technical field [0001] The invention relates to a detection device and a detection method for an insulation fault, in particular to a detection device and a detection method for an insulation fault between turns of a generator rotor winding. Background technique [0002] Due to poor manufacturing quality, improper maintenance, untimely operation and maintenance, etc., insulation faults such as rotor grounding and winding inter-turn short circuit often occur in the rotor winding of the generator. The rotor grounding fault can generally be detected by measuring the insulation resistance test, but for power generation Although there are some detection methods for inter-turn short circuit faults of rotor windings, such as air gap coil method, AC impedance and power loss method, DC resistance method, no-load and short-circuit characteristic test method, etc., there are certain deficiencies. They are as follows: [0003] (1) AC impedance method and power loss method [0004] The...

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Problems solved by technology

Therefore, similar to the DC resistance method, the no-load and short-circuit characteristic method is not sensitive enough for the detection of inter-turn short-circuit faults, and can only be used as one of the methods for comprehensively judging whether there is an inter-turn short circuit in the rotor winding of a generator.

[0012] The sensitivity of the above detection methods, the difficulty of test detection, the accuracy of fault location and the overall performance of the detection methods are evaluated. The DC resistance method and the AC impedance method can perform static detection of shutdown, but the detection accuracy and sensitivity not tall

The no-load and short-circuit characteristic test method and the air-gap coil detection method are suitable for detection in the rotating state. Due to many influencing factors, the accuracy and sensitivity are not high

Especially when the generator set is shut down for minor repairs, the rotor is generally not pumped, it is sealed in the stator bore, and only simple direct resistance, AC impedance and power loss measurements can be performed. If the detection is inaccurate, it will be extremely unfavorable to the safety of the generator.

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