Orthogonal decomposition of currents, power definitions and energy transmission in three-phase systems treated in the time domain.

Abstract

This paper deals with the orthogonal decomposition of currents in a three-phase system. Currents and voltages of the three-phase system are treated as instantaneous values and as continuous functions defined in given interval. In both cases current and voltage vectors are defined. They are decomposed into two orthogonal components. The first one is collinear with the voltage vector while the second one is orthogonal to it. It is shown, that only the current vector component collinear with the voltage vector contributes to the energy transmission and to active power while the current vector component orthogonal to the voltage vector causes reciprocal energy exchange between source and load whose average value equals zero.