Design optimization of distribution transformers by minimizing the total owning cost

This paper presents a new optimization problem for the design of distribution transformers under the strict requirements on energy efficiency imposed by modern standards and directives. The proposed methodology is devoted to the minimization of the total owning cost of the transformer while meeting a set of constraints that includes all the phenomena implied in the transformer operation. In particular, both electromagnetic and thermal aspects are considered and their relationships with electrical and geometrical variables are accurately detailed. Furthermore, the power losses in both core and windings are accurately derived and the limitations imposed by the standards are taken into account by imposing proper constraints. The generality of the proposal allows considering different technological solutions in material used for the core. The results proposed in the numerical applications showed the effectiveness of the proposed procedure and permitted highlighting the feasibility of different solutions.