Naoyuki Kurita, Hitachi Ltd.
Recently, requirement of low noise transformer have been increased as load noise was standardized in IEC in 2001. The major cause of transformer noise is core vibration, which is mainly due to the magnetostriction and the electromagnetic forces of electrical steel. This presentation introduces the developing 3D electromagnetic analysis technology to estimate the core noise of large transformers. First, we indicate the validation of efficiency of magnetostriction analysis function in JMAG, and the comparison of measured and calculated results of the natural vibration modes of a three-phase model core. Next, we’re planning to explain a perspective to improve the accuracy of the vibration analysis model for transformer cores considering the magnetostriction force.