Apparent Power (S): Single phase: $S = V \cdot I$. Three phase: $S = \sqrt{3} \cdot V_{LL} \cdot I_L$

Real Power (P): $P = S \cdot \cos(\theta) = S \cdot PF$

Reactive Power (Q): $Q = S \cdot \sin(\theta) = \sqrt{S^2 - P^2}$

PFC Capacitor: Required compensation $Q_c = P \cdot (\tan(\theta_{old}) - \tan(\theta_{new}))$.
$C = \frac{Q_c}{V^2 \cdot 2 \pi f}$