Influence of the representation of the distribution transformer core configuration on voltages developed during unbalanced operations

Abstract

The object of this paper is to emphasize the importance of the representation of the core configuration when seeking transients developed in a distribution transformer under an unbalanced situation. Digital time-domain simulations are performed with the Alternative Transients Program (ATP) for the case of a distribution three-phase transformer using the following two core configuration representations available in the ATP: three-legged core form and fivelegged core. Severe overvoltages and high saturated currents would not be evidenced if the wrong core configuration representation was used during simulations.