Techno-economic comparative evaluation of mixed and conventional magnetic wound cores for three-phase distribution transformers

•Mixed, three-phase, wound core, distribution transformers are proposed.•Advantages include reduced total owning cost for a wide range of variables.•High ratings and high sales margins favor the mixed three-phase transformer design.•Long transformer lifespan and high magnetization levels favor conventional designs. This paper presents a comparative evaluation of conventional and mixed magnetic wound cores for three-phase distribution transformers. The authors utilize a techno-economic analysis based on an analytical approach in order to determine the variables that differentiate the mixed three-phase transformer from the conventional one. The techno-economic characteristics of two 100kVA three-phase transformers, a conventional one manufactured of HiB electrical steel and a mixed one manufactured of conventional and HiB steels, are compared using an estimator function and laboratory tests. The authors demonstrate that the mixed three-phase transformer presents improved characteristics over the conventional one for a wide range of sales margins, material costs, magnetization levels, and geometric variables. As a consequence, mixed magnetic wound cores can be an excellent alternative for the E.U. distribution networks where it is necessary to reduce losses, greenhouse gas emissions, and energy costs.