Influence of Non-Uniform Temperature Distribution on Elastoplastic Deformation of Windings

Abstract

To accurately analyse the deformation of transformer windings under short-circuit conditions, a three-dimensional multiphysics field simulation model of the magnetic-fluid-thermal-structural coupling is constructed. The current magnitude under rated and short-circuit conditions of the transformer are calculated, the magnetic field distribution is obtained based on the current, and the loss is calculated as the heat source for temperature simulation. The temperature distribution results and short-circuit electromagnetic force are used as initial conditions for structural field simulation to analyse the elastic-plastic deformation, residual stress, and residual deformation of the winding under short-circuit impact. Considering the non-uniform distribution of winding temperature, compared with the results of the uniform temperature distribution, the maximum plastic strain of the winding increases by 84.6% after being subjected to short-circuit impact. The position of the wire cake where the maximum residual stress and residual deformation of the winding are located is different, and the values increase by 13.5% and 95.3%, respectively. Therefore, considering the non-uniform temperature distribution during the simulation process is more closely related to the actual working conditions, and thus more accurate in obtaining the location where cumulative deformation occurs.