Reactive power

The notion of reactive power has been introduced long time ago because of its advantages to describethe behaviour of a power system. Among these advantages are the facts that the reactive power is ascalar quantity (therefore easy to manipulate) and that it is conserved over any network.Over the time, the meaning of the original concept of reactive power has been lost and today the“reactive power” is used for the maximum reactive power that flows through a piece of electricnetwork. The change of meaning is the origin of a few misconceptions that are present in almost everytextbook today. This article reanalyzes the reactive power concept, identifies the present contradictionsand defines clearly the differences between reactive and active power.