Analysis of mechanical characteristics of transformer windings under short circuit fault

Abstract

The insufficient ability to withstand short circuit of power transformer seriously affects the safety of power system, so it is very necessary to calculate short circuit strength of windings accurately. Two-dimensional electromagnetic-structure coupling method is applied to calculate the mechanical properties of windings for a 220 kV power transformer. The distribution of stress and displacement of the power transformer windings are obtained and analyzed under short-circuit fault. The result reflects The result reflects the leakage flux density between high and low voltage windings is higher than that in other parts of the windings. The two windings are subjected to compression from both ends to the middle, and the maximum stress occurs in the middle of low-voltage winding while the maximum displacement occurs in the end of high-voltage winding under the axial electromagnetic force. The maximum stress appears at the point of the disk near the vertical spacer, and the mimimum stress appears at the point in the middle of two adjacent vertical spacer of the disk, under the radial electromagnetic force. The maximum displacement appears at the point in the middle of two adjacent vertical spacer of the disk, and the mimimum displacement appears at the point of the disk near the vertical spacer.