Detailed modeling of eddy current effects for transformer transients

A detailed time domain model for the eddy current losses in the windings of a transformer is presented. The basic elements for the derivation of the model are the turns which may be combined into sections. The model is expressed as an R-matrix. Its diagonal elements were fitted using a series Foster circuit while for the off-diagonal elements the authors used the basis functions of the Foster circuits to derive the time domain model in the form of state equations. For validation, the losses computed with the detailed model are compared with those obtained by considering full windings. The frequency response of the transformer model is compared with test results. Simulations are presented for illustration and further validation