What is reactive power in an AC system?

Reactive power in an AC system refers to the power that oscillates between the source and the load. This type of power does not do any actual work but is essential for maintaining the electric and magnetic fields in inductive and capacitive components of the system, such as motors and transformers.

In an alternating current (AC) circuit, the flow of current and voltage can be out of phase due to the presence of inductive or capacitive elements. Reactive power is measured in volt-amperes reactive (VAR) and indicates how much power is being stored and released by these components during the AC cycle. Essentially, reactive power helps sustain the voltage levels necessary for the system to function effectively, even though it does not contribute to the actual power that performs useful work.

In contrast, other elements of reactive power pertain to the directions and types of power flow. Power that flows in one direction only describes real power, which does do work. Power used to maintain system voltage relates more closely to the concept of reactive power but fails to capture the oscillatory nature of its flow. Finally, power consumed by resistive loads refers to real power, which is entirely focused on useful work performed without the cyclical exchange typical of reactive power. Therefore, the oscillating