Voltage transformer vibration fault feature extraction method based on improved EMD method and Spectral Kurtosis method

Abstract

The invention relates to a voltage transformer vibration fault feature extraction method based on an improved EMD (empirical mode decomposition) method and a Spectral Kurtosis method. The problem that traditional empirical mode decomposition can lead to a false component can be effectively solved via the improved empirical mode decomposition method based on the proportion of energy moments and the contribution rate of variance. Feature information of original signals can be accurately reflected by an empirical mode component (IMF) which is obtained through EMD noise reduction operation and signal reconstruction. The method put forward in the invention is characterized in that original vibration fault signals are subjected to noise reduction operation and reconstruction, high frequency noise can be eliminated, influence exerted by low frequency interference can be lowered, the kurtosis value of a signal to be analyzed is improved, and the accuracy of vibration fault feature frequency extraction based on the Spectral Kurtosis method can be further improved through preprocessing operation conducted based on the above methods.

Description

technical field [0001] The invention relates to the field of fault detection of oil-immersed power transformers, in particular to a transformer vibration fault feature extraction method based on improved EMD and spectral kurtosis method. Background technique [0002] Changes in the health status of 110kV power transformers directly affect the stability of the power system. Transformers that have been operating with load for a long time have been working in harsh environments, and the transformer itself is in a sub-healthy state. Therefore, it is necessary to monitor and monitor the health status of the transformer in real time. Evaluation. Transformer core and winding failure is one of the main reasons affecting its health status. When the transformer core or winding fails, the vibration signal will be transmitted to the surface of the body through its internal medium, and the abnormality of the vibration signal on the surface of the transformer body caused by the fault It ...

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Problems solved by technology

[0012] However, the traditional Empirical Mode Decomposition (EMD) mentioned in the background technology has a defect in its own decomposition rules, and there are false IMF components in the decomposition results, especially low-frequency false IMF components, which will have a greater impact on the extraction, analysis and processing of fault characteristic signals , therefore, it is very necessary to remove the spurious components obtained after EMD decomposition

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