Influence of Mechanical Stresses Noncoaxial With the Magnetizing Field on the Relative Magnetic Permeability of Electrical Steel

The influence of operation conditions plays a significant role in the functional characteristics of power transformers. This article presents a new approach for modeling the stress dependence of relative magnetic permeability of grain-oriented electrical steels subjected to the influence of mechanical stresses noncoaxial with the magnetizing field. The proposed model utilizes a magnetic domain wall energy-based approach, which allows explanation and quantitative modeling of the stress dependence of 2-D magnetic permeability. Moreover, this article presents the yoke-based method and experimental setup for measuring tensile stress dependence of 2-D relative magnetic permeability in anisotropic steel sheets. The results of the modeling are in agreement with experimental measurements, which validate the presented model. As a result, the proposed model can be applied for finite elements method-based modeling of the influence of stresses on functional characteristics of power transformers with cores subjected to mechanical stresses.