Assessment of Loss Estimation Methods for Distribution Transformers

Distribution transformer losses are typically estimated through simplified approaches. In general, the simplifications are due to the very low monitoring of distribution transformers. In this paper, case studies are performed to obtain the losses of the distribution transformers from the School Electrical and Computing Engineering of the University of Campinas, considering two scenarios: energy provided by two transformers (300 kVA and 500 kVA), and energy provided only by the 500 kVA transformer. Based on the measurements available at the low voltage side of both transformers, two approaches are assessed considering actual measurements and seasonality effects. Based on estimated losses, the economic impacts of using properly sized distribution transformers are discussed as well.