Analysis of zero sequence passive filter harmonics mitigation device for building wiring system

In a normal office building wiring system, the supply is a three-phase four-wire system and most of the nonlinear loads are single phased such as personal computer and electronic office equipment. Rising main installation forms the skeleton of the building wiring system. For balanced systems triplen harmonic components of current are added in the neutral conductor, other components are cancelled. In unbalanced condition triplen harmonics and other components of current flow through the neutral conductor. Therefore, a measure of neutral current is important and this will reflect an elementary impression of power quality of the wiring system. Zero sequence harmonic mitigation such as installation of filter in the neutral conductor and its location are suggested. Moreover, this paper has also explored the third harmonic influence on neutral-earth voltage.