Doubly-fed asynchronous induction generator stator-side turn-to-turn short-circuiting fault diagnosis method

Abstract

This paper discloses a doubly-fed asynchronous induction generator stator-side turn-to-turn short-circuiting fault diagnosis method. The method includes the following steps that: a current transformeris adopted to receive doubly-fed asynchronous induction generator stator-side current signals; a series of eigenmode function components of the current signals are obtained through an empirical modedecomposition module in Hilbert-Huang transformation; Hilbert transformation is performed on each eigenmode function component through a Hilbert-Huang transformation module, so that the Hilbert spectrum of the original signals can be obtained; and a turn-to-turn short-circuiting fault and the appearance time and termination time of the turn-to-turn short-circuiting fault are determined according to the instantaneous amplitude or instantaneous frequency of the eigenmode function component in the fifth layer or the fourth layer, and therefore, the real-time monitoring of the generator stator-side turn-to-turn short-circuiting fault can be realized. According to the method of the invention, the IMF amplitude of the signals in the fifth layer or the fourth layer changes abruptly during the Hilbert-Huang transformation regardless of a no-load condition, a half-load condition or a rated load condition, so that the method can provide an effective guarantee for the timely detection and maintenance of turn-to-turn short-circuiting faults compared with a method adopting traditional FFT and wavelet analysis.

Description

technical field [0001] The invention relates to the field of fault diagnosis of wind power generators, in particular to a method for diagnosing faults of inter-turn short circuits on the stator side of a doubly-fed asynchronous wind power generator. Background technique [0002] As a renewable energy source, wind energy is receiving more and more attention. Doubly-fed asynchronous wind turbines occupy a large market share in wind turbines. In order to ensure the safe operation of the motor, conduct timely maintenance and improve the reliability of operation, and maximize the use of wind energy, online monitoring and early fault diagnosis of the motor have Significance. The insulation deterioration of stator windings of double-fed asynchronous wind turbines is the main cause of motor failure. The stator fault starts from the deterioration of inter-turn insulation, and then inter-turn short circuit occurs. Therefore, it is necessary to detect the inter-turn short circuit in...

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Problems solved by technology

However, the wavelet transformation is mainly based on the Fourier transformation, which inevitably has the limitations of Fourier analysis

For signals whose normal frequency is basically the same as the fault frequency or whose changes are weak, such as small changes in the signal caused by early turn-to-turn faults, wavelet transformation cannot effectively extract its fault characteristics

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