No abstract

The influence of overlap length and overlapping design on core loss and magnetizing current of single‐phase two‐leg transformer core has been investigated The investigation was performed experimentally, on scaled models, and numerically, using 2D finite element method Two types of overlapping, mitred and staggered one, were investigated. It has been observed that the influence of overlap length on core magnetic characteristic is much higher in the case of the mitred overlap than that of the staggered one. This difference has been explained by the reduction of core cross section due to the triangle cutout in the mitred overlap.

Calculation of flux distribution in three‐phase three‐limb transformer core has been made using 2D finite element method. The calculation has been performed with and without taking into account lthe hysteresis of magnetic material. Anisotropy of magnetic material has been modelled through the so‐called elliptic permeability model. Comparison of results of calculation and results of measurement has been performed for a scale model of transformer core. An agreement better than 3 per cent has been obtained, for calculated and measured results of third harmonics and of flux distortion factors, when hysteresis has been taken into account. The CPU‐time was 6–10 times longer when hysteresis has been included into calculation.