The effect of neutral path impedance on voltage and current distortion. Part I: Symmetrical and balanced three-phase systems

This paper discusses some peculiarities of voltage and current distortion in three-phase four-wire symmetrical and balanced systems, namely the effects of neutral path inductance. It is shown that the neutral path inductance by hindering the flow of zero-sequence harmonic currents through the neutral, also reduces the intensity of these harmonics contained in the line currents. The price to be paid for this beneficial effect is an increase in zero-sequence harmonics contained in the voltage-to-neutral spectrum and an increase in the voltage drop across the neutral path. The line-to-line voltages remain, practically, not affected by the additional voltage drop across the neutral path.