Calculate sinusoidal reactive power in kvar from kW and displacement power factor, kVA, voltage and current, or reactance and winding current. Estimate lagging-load capacitor correction; final capacitor-bank design requires qualified electrical review.

KVAR Formula

For one sinusoidal reactive winding, reactance magnitude X in ohms (Ω) times RMS winding current I in amps squared gives reactive-power magnitude in VAR. Divide by 1000 for kvar and select inductive (+) or capacitive (−). For three identical windings, multiply the per-winding result by three; use winding current, which differs from line current in delta.

Q(VAR) = X I²; kVAR = (X I²) / (1000)

Where Q is the reactive power in VAR
kVAR is reactive power expressed in kilovolt‑ampere reactive (1 kVAR = 1000 VAR)
X is the net reactance of the single winding or circuit in this example (ohms)
I is the RMS current through that same winding or circuit (amps)

For the one-winding example, multiply reactance magnitude by winding current squared, then divide by 1000. Select the reactance/current mode above; the other modes use the sinusoidal power triangle or lagging-load correction formula.

KVAR Definition

What is KVAR?

kVAR (kilovolt‑ampere reactive) is a unit used to express electrical reactive power in AC power systems. Reactive power is associated with energy that oscillates between the source and reactive components (inductors and capacitors), and it is commonly discussed in power factor correction and capacitor bank sizing. (1 kVAR = 1000 VAR.)

Example Problem

How to calculate KVAR?

First, determine the reactance of the savings system.
For this problem, the reactance is calculated to be 40 ohms.
Next, determine the current of the system.
For this example, the current of the circuit is measured to be 150 amps.
Finally, calculate the KVAR.
Using the formula above, the kVAR is calculated to be:
kVAR = (X · I^2) / 1000
kVAR = (40 · 150^2) / 1000
kVAR = 900 kVAR