Analyzing the abnormal vibration noise rule caused by DC bias on the transformer is a prerequisite to prevent fault of transformer. Therefore

as for type E power transformer

the vibration and noise mechanism of transformer under DC bias is analyzed in accordance with the“core-winding”modeland the multi-physical field coupling model of electromagnetic-vibration-sound field is set up by Comsol. The rule of the vibration noise of DC bias on transformer in different operation conditions at such two cases as magnitude of the direct current

flow of DC current from the primary winding and secondary winding and the influence on winding voltage and current are studied. The study shows that the influence of direct current flowing from the primary winding on the no load transformer is maximum.With the increase of direct current

the vibration noise on the core winding increases and the maximum value of the vibration noise is distributed on the core. The influence of the direct current flowing from the secondary winding on the short circuit transformer is maximum. With the increase of direct current

the vibration on the core winding has slight increase and the maximum value of the vibration noise is distributed on the winding. The distortion of the voltage and current waveform of the winding

in case of flowing of direct current from the primary winding

becomes more obvious. Therefore

in case of DC bias protection and in case of the flow of the direct current from the primary winding

the no load transformer is taken as the reference

while in case of flow of the direct current from the secondary winding

the short circuit transformer is taken as the reference.