In order to realize effective feature extraction for vibration signals of power transformers
a method of signal feature extraction based on empirical wavelet transform(EWT)is proposed. Firstly
transformer vibration signals in different working conditions are decomposed into several empirical wavelet functions(EWFs)through the method of EWT. Secondly
the Hilbert spectrum of each EWF is calculated
and the frequency characteristics of transformer vibration signals in different working conditions are shown in time-frequency representation. Finally
the correlation coefficient of each EWF and the original signal is calculated to extract components of high correlation. The eigenvectors of signals are built according to the energy of components above to quantize the features of transformer vibration signals. It is shown by experiment that this method has a good effect on feature extraction for vibration signals of power transformers
and the different transformer winding conditions can be recognized correctly through the extracted eigenvectors.