Analysis of transformer bias vibration based on "magnetic-mechanical" coupling

Abstract

The large-scale application of flexible DC power transmission technology leads to DC bias in transformer cores, and the vibration analysis of transformers under the influence of DC bias is becoming a hot topic. In this paper, based on the "electromagnetic-mechanical" coupling model, we propose a bias vibration analysis method for large power transformers. The electromagnetic forces calculated in the electromagnetic field are mapped to the surfaces of structural members and tanks in the structural force field by means of a grid mapping method, facilitating the direct calculation of transformer vibration displacements under DC bias conditions. Finally, based on the coupled magnetic-structural analysis, the maximum deformation of different structures of the transformer under different DC bias magnetism is studied. The vibration response band of the transformer is above 100Hz, where the DC input of 25A per phase causes the maximum displacement deformation of 39.06mm in the transformer tank, which provides the analysis basis for the safe operation of the transformer.

Keywords

• transformer
• vibration
• dc bias
• magnetic
• mechanical