Volt-var Control

Volt-var control adjusts a plant’s reactive power as a function of measured voltage, absorbing reactive power when voltage is high and injecting it when voltage is low.

The relationship is a piecewise curve with a deadband around nominal voltage. Inverters can supply reactive power without consuming stored energy, which makes a battery or solar plant useful for holding local voltage inside limits. IEEE 1547 defines volt-var as a required capability for distributed resources and IEEE 2800 does the same at transmission scale. A power plant controller coordinates the setpoint across all inverters so the plant meets its target at the point of interconnection.

Also called: Voltage regulation, Reactive power control, Q(V) control