Cost Evaluation of Ohmic Losses in a Distribution Transformer due to Balanced and Unbalanced Loading (A Case Study of New Idumagbo 2 x 15-MVA, 33/11-kV Injection Substation)

Abstract

This study shows the evaluation cost of ohmic losses due to balanced and unbalanced loading in a distribution transformer. Load readings were taken from all public and private 11/0.415-kV distribution transformers fed from the New Idumagbo Injection substation, 2 x 15MVA, 33/11-kV. The results showed that cost evaluation due to copper losses for both balanced and unbalanced load for Adeniji Adele feeder was $185,884 and $191,990 respectively for the period (June 2012 to May 2013) under review.  For Tokunboh feeder, balanced and unbalanced cost was $91,334 and $95,919 respectively. Also, the cost due to copper losses  due  to balanced and unbalanced load for Dolphin feeder was $77,774 and $81,995 respectively. The result of the comparison between balanced and unbalanced loads showed that $14,912 would have been saved if the loads were to be balanced. Therefore, cost evaluation of copper losses varies considerably with the degree of load imbalanced.

Keywords: Substation, Transformer, Fault, Feeders.