The var, volt-ampere reactive, measures reactive power. It is dimensionally the same as the watt and the volt-ampere but kept as a separate name so the three quantities are never mixed up. Capacitor banks are sized in kvar, generator reactive capability in Mvar, and control rooms talk simply of vars, with import and export or a sign showing direction of flow.
Ask the wind farm for 20 Mvar more, the 132 kV is sitting at 0.96 and we're short of vars in the south.
Also heard as
- VAr
- volt-ampere reactive
Related terms
Reactive power
Power that surges back and forth between the source and the fields of inductors and capacitors, doing no net work.
Power factor
Ratio of active power to apparent power, showing how much of the current drawn does useful work.
Apparent power
Product of RMS voltage and RMS current, the figure transformers, generators and UPS units are rated on.