Losses calculation in oil immersed distribution transformers

In this study, the losses of oil immersed distribution transformers are studied. For this purpose theoretical and practical losses of three different three-phase distribution transformers with different power ratings (100kVA, 160kVA, 250 kVA) are analyzed and the results obtained from these analysis are compared. The difference between the results and the reasons of these errors are studied. In theoretical study the effect of harmonics on transformer losses has not been considered. The error of theoretical and practical results is small. Leakage losses and the effect of harmonics on the core and conductors losses make some of these reasons.