A component of apparent power (volt-amps) which does not produce any real power (watts) transfer (the sine of the phase angle between the current and the voltage). [Go to source
Reactive power is the difference between apparent power and real power. It is calculated by subtracting real power from apparent power. Reactive power is measured in VAR (volt-amps reactive) or kVAR (kilovolt/amps reactive)
The portion of Apparent Power that does no useful work in an Electrical Circuit. It is commonly measured in kilovars ( kVARS) and must be supplied to most types of equipment with "Coils" of Wires using magnetic fields (i.e. Motors) to magnetize the Motor Windings. It is supplied by the Generator or by Capacitors.