Abstract:Transformer diagnostic technology based on vibration and audible sound has become a research hot topic by virtue of its advantages of no electrical connection with the monitored equipment, strong anti-interference ability and high sensitivity. In this paper, in order to analyze the characteristics of the audible acoustic signal of the transformer, the mechanism of the audible audible generation of the transformer is analyzed theoretically. The fast Fourier transform and wavelet decomposition method are used to analyze the audible acoustic signals of transformers under different operating periods, different voltage levels, different acquisition positions and different load rates. The frequency spectral and wavelet energy eigenvectors of the signals are obtained. The results show that the main frequency of the audible signal is 100Hz, and there are 200Hz, 300Hz and other high Sub-harmonic components; but with the increase of transformer operating life and voltage level, the main frequency increased to 200Hz, the high Sub-harmonic ratio and high-frequency energy characteristic value increased; The signal spectrum and energy characteristic value are affected by the acquisition position, and the appropriate collection position should be selected according to the actual situation of the transformer structure.