Lightning Electric Field Analysis of a Transformer Using ANSYS Maxwell

Lightning strike is a very important phenomenon for all electrical power systems because of over voltage impulse. Thus, lightning analysis is equally important for power issue. In this paper, lightning electric field analysis of an oil type distribution transformer with a 25-kVA power capacity using ANSYS Maxwell simulation program are proposed. Lightning impulse voltage applied to transformer, electric field and voltage distribution of the transformer during lightning are presented with simulation results. Critical regions that can cause breakdown on insulation materials between primary and secondary windings are shown as three dimensionally. Electric field distribution on critical regions on insulation material of two-dimensional model is also shown. The comparison of three and two-dimensional analyses are compared for insulation breakdown during lightning analyses. This paper provides advantage researchers and engineers whom design/produce/choose the transformer bushings/isolators and other insulation materials on a simulation program such as ANSYS. In future, optimization study for insulation materials and partial discharge localization will be done.