DOES THE INSTANTANEOUS REACTIVE POWER P-Q THEORY SPECIFY POWER PROPERTIES OF ELECTRICAL LOADS?

摘要

The paper investigates how the Instantaneous Reactive Power (IRP) p-q Theory describes power properties of electrical loads operating under sinusoidal conditions. This study demonstrates that the IRP p-q Theory suggests the presence of a reactive current in supply lines of purely resistive loads and the presence of an active current in supply lines of purely reactive loads. Moreover, it suggests the presence of nonsinusoidal current components in linear circuits with sinusoidal supply voltage. This study shows moreover that the IRP p-q Theory does not identify power properties of three-phase loads instantaneously. A pair of instantaneous values of p and q powers does not allow us to conclude whether the load is resistive, reactive, balanced or unbalanced. Moreover, this study shows that the p-q Theory does not identify the load imbalance as the cause of the power factor degradation. Consequently, investigations reported in this paper indicate that the Instantaneous Reactive Power p-q Theory seems to misinterpret power phenomena in unbalanced systems with sinusoidal voltages and currents.