Power factor correction calculator
Enter the active power and the present and desired cos φ, and we calculate the required capacitor power and the current before and after the correction.
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How do we calculate power factor correction?
Power factor correction reduces the reactive power with a capacitor, so the apparent power and the current of the load become smaller. The required capacitor power is:
Q = P · (tg φ₁ − tg φ₂)
where P is the active power in kW, and φ₁ and φ₂ are the angles of the present and the desired power factor (you enter the values of cos φ₁ and cos φ₂). The result gives the capacitor power in kvar (kilovolt-ampere reactive).
What else does the result show?
The apparent power (kVA) and the current (A) before and after the correction, on a single-phase (230 V) or three-phase (400 V) network. This shows how much the load on the cables and the protection decreases.
What to watch out for
The target cos φ should be higher than the present one, and at most 1. Size and connect the capacitor according to the manufacturer's data and the designer; the calculator is informative. Take the active power and the present power factor from measurement or from the supplier's bill.
Frequently asked questions
What does kvar mean?
The kvar (kilovolt-ampere reactive) is the unit of reactive power. The power of a capacitor is also given in it.
Does it calculate for single- and three-phase networks too?
Yes. The capacitor power uses the same formula; the network determines the current (230 V or 400 V).
Related pages
- Power and current converter – with cos φ, on single- and three-phase networks
- Cable cross-section and MCB – for the corrected current
- Electrician calculators – all the calculators
In detail in the tutorial
- Distribution boards, single-line diagram and sizing – power and current on the board