Experimental investigations on effect of core production attributes on transformer core loss performance

In an attempt to determine the magnitude of the effects of a number of core production attributes; such as core quality, joint stacking, clamping pressure, etc. on the performance of stacked cores, a comprehensive experimental and analytical study has been conducted. These effects were studied for different core material grades, and for both single and three phase cores. The two performance parameters studied are core losses and core exciting current. This paper presents the results of the experimental part of the study. The experimental models used in the study were designed such that they depict the performance of full size cores. In addition, some tests were made on full size cores to verify the effect of core yoke clamping on core loss. The results presented in this paper have already been used by ABB transformer plants world-wide to improve core performance as well as improve the accuracy of core loss and core exciting current calculations at the design stage.