Reduction of the net harmonic current produced by single-phase non-linear loads due to attenuation and diversity effects

Abstract

The increasing use of compact fluorescent lights, as well as single-phase electronic loads, has the potential to increase the overall harmonic distortion levels on distribution systems. The possible impact of the interactions between both load voltage and current harmonics due to the presence of the source impedance is studied. The effects of varying the load power levels and combining different load types on the current harmonic distortion are also analyzed. The analysis uses the electromagnetic transient program (EMTP) to model the different loads as well as the whole system. The computer simulations are supported by laboratory testing. The main conclusion of this work is that neglecting the source impedance will result in overestimating the current harmonics produced by non-linear loads. The harmonic levels are reduced due to both attenuation and diversity of harmonic phase angles among different load types. We also conclude that using a combination of different load types can result in a reduction of the current distortion.