Correlation of magnetostriction variation on magnetic loss and noise for power transformer

Abstract

Magnetostriction (MS)-caused strain in single-phase three-legged cores with different core cutting forms, which suffer from induced magnetic loss and noise, was studied. It is found that adopting each different core form types induces magnetostriction ε variation in a transformer core operating with a high-frequency AC signal. The results are compared with finite element analysis simulations. It is also indicated that magnetostriction ε variations are significant in the rolling direction and along limbs and yokes. In this paper, it is proposed that core corner sides and T-joint parts without cutting structure, the core exhibits lower core loss and lower heat dissipation due to the fact that the magnetic flux that passes through corner sides shows lower magnetostriction variation. The magnetic properties resulting from magnetostriction variation in core loss and heat dissipation phenomena are significantly different from other core forms because of stronger contributions from magnetostatic forces. The main contribution for reducing core loss and noise, making them much less in corner numbers and cutting-fabricated forms, can be expected to come from lower magnetic flux and magnetostriction variation.