Investigation of the effect of harmonic currents on losses of phase shifting transformers and its realization using a 15-degree phase shifting transformer

Abstract

The trend of energy savings has been widely interested and phase shift transformers (HMT) have been extensively used. This paper presents the investigation of the effect of harmonic currents on losses of the HMT. In this paper, a 15-degree HMT with quad secondary winding is applied to find the relationship between harmonic currents and losses of the HMT. This relation can be met by testing the active power of primary and secondary sides while the HMT supplies for two and four non-linear loads at 25%, 50%, 75%, and 100% rated currents, respectively. The results reveal that harmonic currents affect winding eddy current losses significantly and the losses for loading the two secondaries 1 and 2 are the same as loading the two secondaries 1 and 3 while both %THDi are different. However, for loading the secondaries 1 and 2, the %THDi is more than 15% so it is not met IEEE 519 Std. while the HMT is supplied with four loads, the %THDi has met IEEE 519 Std. and the losses are less than 57% compared to one load. As a result of these, if the HMT is applied to an adjustable speed drive system, it is not only reduced the harmonics but also saved the energies.