An analysis into the effect of voltage harmonics on the maximum loading capability of transformers

In this paper, some exemplary cases are presented to show the effect of voltage total harmonic distortion (THDV) and its spectrum on the harmonic loss factors (F_HL and F_HL-STR) of the six-pulse rectifiers accompanied with a constant power dc load and a battery. Accordingly, the winding losses and maximum loading capability of a transformer supplying both non-linear load types are investigated for sinusoidal and non-sinusoidal bus voltage conditions. The obtained numerical results clearly shows that the current harmonics of the considered non-linear load types are highly dependent on the THDV level and spectrum of the supply voltage, thus, the voltage harmonic profile should be considered in the design stage of the transformers, which are under influence of particular to supply them.