How is reactive power in an AC system expressed?

Reactive power in an AC system is measured and expressed in kilovars. Reactive power is essential in alternating current (AC) systems because it represents the power that oscillates between the source and the reactive components of the circuit, such as inductors and capacitors. This type of power does not result in a net transfer of energy but is necessary to maintain the voltage levels and support the operation of the equipment that uses magnetic fields, such as transformers and motors.

Using kilovars as the unit of measure allows engineers to quantify the amount of reactive power in a system and helps manage system performance, power factor, and overall efficiency. In contrast, other units mentioned—volts, amps, and hertz—are used for measuring voltage, current, and frequency, respectively, but do not specifically relate to the concept of reactive power. Therefore, kilovars is the correct expression for reactive power in an AC system.