Current distribution and leakage impedance of various types of foil-wound transformers

This paper presents an accurate method for calculation of current distribution and leakage impedance of foil-wound transformers. It takes into consideration the curvature of the winding and the presence of iron boundaries. Transformers having various combinations of foil-wound, wire-wound and sectionalised windings are analysed. The influence of the various factors on current distribution and leakage impedance is examined in detail. These factors include the spacing between windings and iron boundaries, the type of windings, the number of sections on the outer winding and various asymmetrical arrangements of windings. Measurements of leakage flux show good correlation with computed results.