Analyzing economic benefit and performance of step - lap cores over conventional cores in distribution transformers

Abstract

The step-lap core manufacturing technique for distribution transformers can be considered as an emerging technology in the transformer industry in the Asian region, but a well practiced design in the European and other developed countries where transformer industry is updated with modern facilities with high tech machinery in their production lines.

The LTL Transformers (Pvt.) Ltd., the sole manufacturer of distribution transformers in Sri Lanka has taken the initiative to purchase a modern core cutting line with the step-lap technology. This project focuses on studying the behavior of core joint and does a comparative evaluation of the performance and economics of conventional cores and step-lap cores in distribution transformers.

In particular, the effects of core joints on core performance were studied. A Feasibility study was done on the LTL design cores. The Step-lap cores were manufactured using the available core cutting line and the performance data were compared with diet of conventional type cores.

The study shows that the core loss in distribution transformers can be reduced by about 8% with the introduction of the step-lap core. The study concludes by showing that replacing the conventional core cutting line with modern high-tech machine for producing step-lap cores is viable with a payback period of 7 to 8 years.