Energy efficiency rating of transformers under unbalanced linear regime

This paper presents a mathematical model used to calculate the symmetrical components depending on load current (actual values and phases) in low voltage electrical distribution networks. Based on the mathematical model proposed, transformer losses were evaluated for two windings transformers. Case studies dealt with non-symmetric mode due to load unbalance in the low voltage distribution network. Analysis of case studies was performed by modifying the actual value of the phase currents and differences related. The important assumption made was that the distribution network has symmetrical phase voltages.