Coupled Field Method for Analyzing Short-Circuit Electromagnetic Forces in Power Transformers

Abstract

The electromagnetic forces can induce critical stress on transformer winding during short circuit. The forces in axial direction can damage the insulation and result in transformer insulation getting damaged. In this paper, axial electromagnetic forces in low voltage (LV) winding and high voltage (HV) winding of transformer are analyzed during three-phase short-circuit condition. The flux density and axial electromagnetic forces are analyzed using coupled field method. All simulations of the coupled field theory are carried out for a three-phase 10 MVA 33\11 kV power transformer. The cumulative axial forces during short-circuit condition in the LV and the HV winding are computed. The net axial forces in both the windings are assessed.