Research on Electromagnetic Force of Transformer in Different Short-circuit Modes

Abstract

When a short-circuit fault occurs on a power transformer, the windings of the transformer under the combined action of the short-circuit current and the leakage magnetic field, which is easy to deform the winding or damage the insulation of the transformer. Therefore, it is necessary to research on the force of the transformer under short-circuit situation, analyze and calculate the size and distribution characteristics of the electromagnetic force in different short-circuit modes. Based on the structural parameters of a transformer with a rated capacity of 200kVA, a three-dimensional model of a three-phase transformer is established by finite element simulation software. The axial and radial electromagnetic forces of windings in different short-circuit modes are analyzed by this model, comparing and analyzing the experimental results. In the simulation model, It can be known that the electromagnetic force of voltage zero-crossing closing phase when three-phase short-circuit occurs on low-voltage winding is basically the same as that of short-circuit phase electromagnetic force when single-phase short-circuit occurs. The analysis results have a certain reference value for improving transformer short-circuit withstand ability.