Global energy and environmental issues are becoming increasingly problematic

and the vibration and noise problem of 110 kV transformers

which are the most widely distributed

have attracted widespread attention from both inside and outside the industry. DC bias is one of the main contributing factors to vibration noise during the normal operation of transformers. To clarify the vibration and noise mechanism of a 110 kV transformer under a DC bias

a multi-field coupling model of a 110 kV transformer was established using the finite element method. The electromagnetic

vibration

and noise characteristics during the DC bias process were compared and quantified through field circuit coupling in parallel with the power frequency of AC

harmonic

and DC power sources. It was found that a DC bias can cause significant distortions in the magnetic flux density

force

and displacement distributions of the core and winding. The contributions of the DC bias effect to the core and winding are different at

K

dc = 0.85. At this point

the core approached saturation

and the increase in the core force and displacement

slowed. However

the saturation of the core increased the leakage flux

and the stress and displacement of the winding increased faster. The sound field distribution characteristics of the 110 kV transformer under a DC bias are related to the force characteristics. When the DC bias coefficient was 1.25

the noise sound pressure level reached 73.6 dB.