Noise and vibration signals contain rich information about transformer’s mechanical state. Combination of noise voiceprint imaging technology and vibration signal analysis is an effective method to detect the mechanical states of transformer winding and iron core. The analyses of transformer’s noise voiceprint and vibration signal results are of great importance to transformer fault diagnosis. In this study

a noise and vibration measurement system was established based on the analyses of the noise and vibration mechanisms of transformer’s iron core and winding

and a 110 kV transformer was measured. According to the analysis results of voiceprint imaging based noise source location and vibration signal’s characteristic value

the transformer was judged to have a fault in its C-phase high-voltage level bushing

verifying the effectiveness of the proposed diagnostic technique.