Definition: A kilovolt-ampere reactive (kVAR) is a unit of measurement for reactive power, equal to 1000 VAR (Volt-Amperes Reactive). Reactive power represents the energy that oscillates between the source and the load without performing any real work.

History/origin: The kilovolt-ampere reactive (kVAR) is based on the concept of reactive power in AC systems, which emerged in the late 19th century. The 'kilo-' prefix indicates a factor of 1000, making kVAR a more convenient unit for larger reactive power quantities.

Current use: kVARs are commonly used to measure and manage reactive power in industrial and commercial power systems, as well as in distribution networks. They are used in specifying the size of reactive power compensation equipment, such as capacitor banks and reactors, used to improve power factor and voltage stability.