Multi-scale computations of parameters of transformer windings at high frequencies. Part I

Artikel i vetenskaplig tidskrift, 2007

A hierarchical multi-scale approach to modeling of high frequency phenomena in power transformers is proposed. The method is based on considering high frequency effects on two spatial levels. Part I of the paper focuses on a small-scale level where eddy current as well as geometrical and proximity effects in conductors of transformer windings are examined. The developed computer model accounts for anisotropic frequency-dependent effective diamagnetic properties of transformer windings, which are represented as composite media with periodic structure. Effective characteristics of the laminated transformer core are calculated taking into account anisotropic magnetic properties of steel sheets. The obtained frequency-dependent parameters of transformer elements are further used in Part II for computing effective inductances and resistances of windings and integral losses on a large-scale level, i.e. for the whole transformer.