In this presentation, the AC resistance of transformer lead-outs is investigated. For this purpose, an equivalent complex permeability model is used. It is shown, that the copper losses can be split into DC (RMS), skin and proximity losses. Parallel bundles of insulated strands are assumed for the leadouts. Hence, the proximity losses are dominated by the inner proximity effect which can be easily calculated by a given approximate formula. Finally, the model is compared to measured data.
