Active and reactive power flow in distorting three-phase unbalanced circuits without neutral

Abstract

A groundbreaking discovery made by Professor Andrei Ţugulea in mid 1980s led to a new approach concerning the power flow analysis in three-phase circuits. The present study is devoted to provide a further insight into the possibilities opened by this new theory, when a three phase circuit has two different unbalanced and distorting consumers powered through a balanced line. Symmetry, non-symmetry and residual (distortion) active and reactive powers are the conceptual quantities introduced by Professor Ţugulea capable to assess the nonlinearity and unbalance effects on power circulation. Correspondingly, three normalized coefficients were defined to allow a more compact representation of the phenomena: symmetry, non-symmetry and distortion power factors. Initially formulated for two balanced linear receptors and a single unbalanced distorting one, the present study considers a single balanced linear receptor and two unbalanced nonlinear (distorting) consumers. All possible cases concerning the active and reactive powers flow directions are put in evidence through different parameter circuits simulated in PSpice. Finally, interpretation of the obtained results is presented and discussed.