Comparison of instantaneous reactive power p-q theory with theory of the current's physical components

摘要

The comparison of the instantaneous reactive power (IRP) p-q theory with the theory of the current's physical components (CPC) presented in this paper pro-vides the relationship between powers in both theories applied to three-phase, three-wire circuits with sinusoidal voltages and currents. It shows that results of the IRP p-q theory are inconsistent with power phenomena in such circuits. Namely, the instantaneous reactive power q may occur in circuits with linear, purely resistive loads thus, with zero reactive power, Q, and the instantaneous active power p may occur in circuits with purely reactive loads, thus, with zero active power, P. Consequently, the IRP p-q theory fails to identify the power properties of three-phase circuits with unbalanced loads. Moreover, in spite of si-nusoidal supply and the lack of distortion, the IRP p-q theory suggests that the active and reactive currents con-tain a third-order harmonic. Also the IRP p-q theory is not capable of providing information on power properties of the load instantaneously.