Eddy current add-on for frequency dependent representation of winding losses in transformer models used in computing electromagnetic transients

A frequency dependent resistance model for the representation of eddy current losses in the windings of three-phase, two or three windings, transformers is presented. It consists of a low order R, L Foster circuit connected in series with any existing transformer model to produce the realistic damping that results from increased losses during transients involving large currents in the windings. This eddy current 'add-on' is easy to realise based on transformer design data or even, in an approximate way, from name plate data. Its significance is demonstrated by comparative simulations. >