Measurement and modeling of magnetostriction characteristics of highly Grain-oriented electrical steel sheet by using round-type two-dimensional single sheet tester.

Magnetostriction in highly Grain-oriented electrical steel sheet (ESS) is a primary source of vibration and acoustic noise of power transformers at no-load condition. Especially rotating magnetization, as it occurs in joint area of three-phase power transformer, makes the magnetostriction bigger and more complex than that under alternating magnetization. Meanwhile, magnetic flux density along transverse direction makes a lot bigger magnetostriction than that under rolling direction. In this paper, a new measuring system of the magnetostriction are developed for a highly Grain-oriented electric steel sheet (HGOESS) of which magnetic domains are bigger in size and higher in degree of alignment than those of a Grain-oriented one. The magnetostriction characteristics of some HGO-ESS are measured by using the developed system under both alternating and rotating magnetic fields. An improved magnetostriction model is also proposed based on the mechanical elasticity, and its effectiveness is validated through comparisons with experimentally measured results from the measuring system. [ABSTRACT FROM AUTHOR]