Capacitor bank size for power factor correction
Calculate the capacitor bank needed to raise cos φ and see the power triangle before and after correction.
01 / MEASUREMENT AND TARGET
Correction
Enter the active power, the present power factor and the target.
Often 0.93–0.95 (tan φ ≤ 0.4). The value comes from your supply contract.
POWER TRIANGLE
CAPACITOR BANK RATING
110.6 kvar
tan φ: 0.88 → 0.33Apparent power before / after267 / 211 kVACurrent after correction79% of present
The result is the bank rating at a constant load. A varying load needs an automatic bank with steps, and distorted current needs a detuned bank with reactors. Base the choice on measurements over a longer period. The result is for preliminary calculations and must be checked in the design and by measurement. It does not confirm that the installation complies with standards.
Method and assumptions
Qc = P · (tan φ₁ − tan φ₂)
P: active power; φ₁, φ₂: phase angle before and after correction. Check example: 200 kW, cos φ 0.75, target tan φ = 0.2 gives about 136 kvar.