The formula below will provide the required capacitance in KVAR to improve the power factor of a low voltage electricity supply from the actual target power factor to the target power factor, usually 0.98.
Qc = KW x ((tan(cos-1(PF)) – (tan(cos-1(Target PF)))
This formula can be used to specify power factor correction equipment. It is important to consider the harmonic distortion of the supply. A supply with high harmonic distortion caused by demand of non-liner loads will require any power factor correction equipment connected to be detuned.