Zero Sequence Voltage Phasor Positioning under Balanced Three-Phase Supply

Based on the representations in barycentric coordinates on a balanced supply line-to-line voltages triangle the resulting complex-plane static phasors of the zero sequence voltage and of the related unbalance factor are obtained for the balanced mode of the three-phase supplying. It is supposed that the voltages and currents are sinusoidal. The suggested formulae calculations require only RMS voltmeter readings of the three line-to-neutral load voltages and could be used as a practical engineering tool to implement a three-phase load circuit monitoring, diagnostics, protection and voltages unbalance compensation. Physical interpretation of the neutral bias voltage phasor barycentric coordinates, corresponding to the coefficients of participation of the individual phase loads in this bias voltage generating, is also presented as the functions of the phase loads electrical admittances parameters.