Power factor correction calculator
Correcting power factor does not reduce real power. It reduces the current carrying it, and therefore the losses and the cable size.
kW
V
Hz
Correction needed
27.662kvar
- Capacitance, delta connected
- 550.31 microfarad
- Line current before
- 96.23 A
- Line current after
- 75.97 A
- Current reduction
- 21.05 %
- Cable loss reduction
- 37.67 %
Show the working
- Real power = 50
- Existing power factor = 0.75
- Target power factor = 0.95
- Line voltage = 400
- Supply frequency = 50
- tan1 = tan(acos(clamp(0.75, -1, 1))) = 0.881 917
- tan2 = tan(acos(clamp(0.95, -1, 1))) = 0.328 684
- Correction needed = 50 * (0.881 917 - 0.328 684) = 27.6616
- Capacitance, delta connected = 27.6616 * 1000 / (2 * pi * 50 * 400^2) * 1e6 = 550.311
- Line current before = 50 * 1000 / (sqrt(3) * 400 * 0.75) = 96.225
- Line current after = 50 * 1000 / (sqrt(3) * 400 * 0.95) = 75.9671
- Current reduction = 96.225 > 0 ? (96.225 - 75.9671)/96.225*100 : 0 = 21.0526
- Cable loss reduction = 96.225 > 0 ? (1 - (75.9671/96.225)^2)*100 : 0 = 37.6731
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- Q = P (tan(phi1) - tan(phi2))
- C = Q / (2 pi f V^2)
- losses fall with the square of the current.
Overcorrecting into a leading power factor is its own problem, and can cause resonance with system inductance.