INVESTIGATION OF ASYMETRIC MODES OF THREE-PHASE THREE LEGS PHASE SHIFTING TRANSFORMER WITH CONNECTION IN DELTA AND TWO ADDITIONAL WINDINGS

Abstract

The model of power three-phase three legs phase-shifting transformer with connection in delta and two additional windings is realized. Calculations and research of steady state asymmetric modes particularities of given transformer with such windings connection were fulfilled, taking into account the electromagnetic coupling of the windings, located on different legs. Calculations and analysis were made using as an example the distribution transformer with 10 kV high voltages, including the most characteristic steady state asymmetric modes that occur during different short circuits and asymmetric no load modes, associated with the occurrence of zero sequence magnetic flux. For the considered modes vector diagrams for currents and voltages, as well as for the relative values of magnetic fluxes in legs were constructed, which in ensemble give clear idea about their particularities.

Keywords

• Power three-phase three legs phase-shifting transformer model