The analysis of optimal energy losses in two-windings transformers

Objective needs for the determination of electric energy losses for two-windings transformers from transformer posts (TP) and transformer sub-stations (TS) are presented in this work. The paper proposes an original mathematical model to determine the energy losses of TP or TS, valid for the general case of one or several transformers (identical or different from their rated characteristics point of view) nonsymmetrically loaded due to the intrinsic structure of the supplied consumers. The optimal electric energy losses due to symmetrical and balanced loading are emphasized, as well as the factors that affect these losses (i.e. load curve fill coefficient, form coefficient, etc.) taking into account the variety and etherogenity of the consumers. The proposed mathematical model has been applied for a TP and a comparison between the actual and optimal energy losses has been considered. The case study comes from a Romanian TP, exploited by the ELECTRICA Electric Energy Distribution Subsidiary of Bucharest.