An original algorithm for the determination of electric energy losses in two-winding transformers from power transformer substations (TS) or transformer posts (TP) is developed in this paper.An adequate mathematical model for the general case of several transformer units (identical or different regarding the rated characteristics) within the same TS/TP is presented, under the assumption of unbalanced and non-symmetrical loading due to customers demand.The optimal energy losses, when symmetrical and balanced loading is assumed, are emphasized, and the authors discuss the factors (in the form of load diagram fill-up coefficient, load diagram shape coefficient, etc.) that may affect them, given the variety and heterogeneous character of customers aggregation supplied from TS/TP.
