Time domain modeling of eddy current effects for transformer transients

Abstract.- Eddy current effects have been included in the model of the transformer for the study of electromagnetic transienfs. Existing analyti-cal formulas for the calculation of losses in the windings have been evaluated. Various equivalent circuits have been fitted to represent in the time domain the damping produced by eddy currents in the windings. A frequency dependent model has been derived for the iron core, based on the physical distribution of losses and magnetization effects. The param-eters of this model are obtained by optimal discretization of the lamina-tions. Simulations of transients have been presented to show the effects of eddy currents in the damping of transients.