Fault Diagnosis Method for Turbine Generator Rotor Turn-to-Turn Short Circuit Based on End Distortion Effect

Abstract

The invention discloses a turbine generator rotor interturn short-circuit fault diagnosis method based on the end distortion effect. The method includes the steps of firstly, installing a magnetic field detection coil on an end distortion magnetic flux path of a turbine generator; secondly, online collecting voltage signals sensed by the magnetic field detecting coil through a data collecting instrument, conducting fast fourier transformation on the signals, and obtaining a spectrogram of the signals; thirdly, diagnosing whether the interturn short-circuit fault exists in rotor windings of the turbine generator or not according to the amplitude changing situation of all spectrum components of the signals. The interturn short-circuit fault in the rotor windings of the turbine generator is diagnosed according to the amplitude changing situation of some characteristic frequency components in the voltage signals sensed by the magnetic field detecting coil, and the turbine generator rotor interturn short-circuit fault diagnosis method has the advantages that diagnosing flexibility is high and sensors are convenient to install, is universally suitable for various types of turbine generators in an electric system, and has wide application prospects.

Description

technical field [0001] The invention relates to a method capable of diagnosing on-line whether there is an inter-turn short-circuit fault in the rotor winding of a synchronous motor, which belongs to the technical field of generators. Background technique [0002] Rotor winding turn-to-turn short-circuit fault is a common fault type of large turbogenerators. The relatively minor rotor winding turn-to-turn short-circuit fault usually does not pose a threat to the operation of the unit, but experience shows that if the fault cannot be found and dealt with in time, the generator Sick operation may further cause serious faults, such as one-point grounding, two-point grounding, and magnetization of the large shaft of the turbogenerator rotor. Although the manufacturing technology of large-scale turbogenerators is constantly developing and improving, the failure rate of inter-turn short circuit of the rotor winding does not show a clear downward trend, but has an upward trend, esp...

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Problems solved by technology

The method leaves a certain margin for system disturbance and power regulation, and is more effective for severe short circuits, while slight inter-turn short circuits (such as 1-turn short circuit) are usually difficult to detect

[0006] The rotor winding turn-to-turn short-circuit fault monitoring method based on the fundamental frequency vibration of the rotor monitors 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. If the rotor is affected The phase of the initial unbalanced external force is opposite to the unbalanced magnetic pull force caused by the short circuit between the rotor turns, so the fundamental frequency vibration of the generator may still be in the normal range after the short circuit occurs, and the fault cannot be detected

[0007] In a word, although the online detection of inter-turn short-circuit faults of rotor windings is paid great attention at home and abroad, the existing methods are still subject to certain restrictions in application, and the results obtained in actual tests are not very ideal. It is not uncommon for cases of inter-turn short circuit failure to be detected in time and cause serious consequences, so it is necessary to further improve the diagnosis level of such faults

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