Calculation of voltage distribution along the transformer winding using the wide band transformer model

Abstract

Electrical devices in transmission and distribution networks are submitted to fast front transients. These transients are often a cause of a failure in the power system. To simulate these phenomena, it is necessary to detailly model all the components of the power system. This paper concentrates on studding transformer internal failures due to voltage stress that can occur when fast front electromagnetic wave travels through the transformer. To prevent a failure, an internal insulation of the transformer has to be dimensioned to sustain these transient phenomena. Therefore, it is necessary to use advanced wideband transformer models for its dimensioning. In this paper, a wide band transformer model based on limited transformer geometry is used to simulate evaluate the stresses on internal transformer insulation in the case of fast front transients. The model is validated for calculation of internal overvoltages with the test case from CIGRE brochure.