Potential for loss reductions in transformers through utilization of third-harmonic flux

The reductions of core loss and excitation current in transformers by the use of third-harmonic flux are introduced through a three-phase transformer consisting of three single-phase transformers. Primary and secondary line voltages remain sinusoidal. Under the same core loss, fundamental flux density can be increased. Experimental results conducted with third-harmonic filters as well as with harmonic-flux injection are studied. The feasibility of loss reductions in three-phase core and shell types and in single-phase transformers is briefly discussed.<>