Reduction of Cost and Losses of Transformers by Using Composite Magnetic Cores

Even though, the transformer is the most efficient of electrical machines, with efficiencies typically in the high 90s, it is possible to reduce transformer costs and losses by using composite magnetic cores. This paper presents a new composite magnetic core that can be used effectively for manufacturing single-phase and three-phase wound core distribution transformers. The new composite wound core concept is based on experimental evidence concerning the flux density non-uniformity of conventional single-phase and three-phase magnetic wound cores and the losses and magnetization properties of conventional and high permeability Si-Fe grain-oriented steels. A systematic experimental losses and flux distribution analysis of single-phase and three-phase magnetic wound cores is undertaken as well as finite element (FE) analysis considering the bulk anisotropic characteristics of laminated wound cores.