Wavelet analysis-based distribution transformer turn-to-turn short circuit monitoring method

Abstract

The invention discloses a wavelet analysis-based distribution transformer turn-to-turn short circuit monitoring method and belongs to the field of distribution transformer short circuit fault recognition. When a distribution transformer turn-to-turn short circuit fault occurs, reactance of windings inevitably changes; despite operation in a power frequency environment, a grounding current of an iron core inevitably contains a high frequency component due to a non-linear property of the iron core. According to the wavelet analysis-based distribution transformer turn-to-turn short circuit monitoring method, the grounding current of the iron core of the transformer is used as a signal source; when the turn-to-turn short circuit fault of the windings occurs, the reactance of windings inevitably changes, and therefore change of the high frequency component contained in signals of the grounding current of the iron core is caused. According to the method, a wavelet multi-resolution technology is used for subjecting the signals to multi-scale decomposition, and the high frequency component of the signals can be obtained; by comparing the sizes of high frequency components contained in signals in different working conditions on the same decomposition scale, the turn-to-turn short circuit fault of the windings of the transformer can be analyzed. A series of laboratory tests preliminarily confirm effectiveness and feasibility of the wavelet analysis-based distribution transformer turn-to-turn short circuit monitoring method.

Description

technical field [0001] The invention belongs to the field of inter-turn short-circuit fault identification of distribution transformers. The invention uses the transformer core ground current, neutral point current and transformer shell ground current as the signal source, and uses the relative size of the high-frequency component contained in the signal under the same decomposition scale under different working conditions as the discrimination standard to realize the transformer winding turn Diagnosis of short circuit faults. When the transformer operates in a power frequency current environment, although the applied voltage of the transformer is a power frequency signal, since the iron core is nonlinear, the iron core grounding current will inevitably contain high frequency components. When the inter-turn short circuit occurs in the winding, the reactance of the winding will inevitably change, which will cause the change of the high-frequency component contained in the curr...

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Problems solved by technology

So far, the monitoring and fault diagnosis methods for the insulation defects of distribution transformers are still blank.

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