Power Factor Correction

To raise the power factor from $\cos\phi_1$ to $\cos\phi_2$ for a load of real power $P$:

$Q_C = P\left(\tan\phi_1 - \tan\phi_2\right) \qquad C = \frac{Q_C}{\omega V^2}$

Example: a 10 kW load at PF 0.7 corrected to 0.95 needs $Q_C = 10(1.020 - 0.329) \approx 6.9$ kvar.

Capacitor banks may be fixed or automatic (switched in steps by a PF controller). Electronic loads (SMPS, LED drivers, EV chargers) use active PFC — a boost converter that shapes the input current into a sine wave.