The present study continues the research presented in a previous article by the same authors focussed on the power theory of Professor Andrei Ţugulea, dedicated to nonlinear three-phase unbalanced circuits. The defined symmetry, non-symmetry and residual (distorting) active and reactive powers flow and conservation are further investigated in three-phase circuits with neutral. Correspondingly, the original theory introduced the symmetry power factor (SPF), the non-symmetry power factor (NPF) and the distorting power factor (DPF) as suitable quantities for characterizing such three-phase circuits (with or without neutral). The paper proves the validity of the theory extended to three-phase circuits with zero impedance neutral on test-circuits simulated in PSpice software. The resulting data are used in a dedicated software usable in on-line or off-line calculations, as well as on power grid automated management.

Keywords: Three-phase unbalanced circuits, Ţugulea power theory, Non-linear loads, Non-sinusoidal regime, Non-symmetry active power, Residual (distorting) active power, Non-symmetry reactive power, Residual (distorting) reactive power, Symmetry power factor (SPF), Nonsymmetry power factor (NPF), Distorting power factor (DPF)