Why is power factor correction important in large building installations?
Most common loads (especially motors) generally appear as a resistance (the power-consumming portion that performs actual work) in parallel with an inductance, which, being reactive, does not contribute to work performed. This normally-small inductance tilts the phase angle between voltage and current such that they aren’t in phase with each other, causing a power factor of less than unity. In this case, the volt-amps product is somewhat higher than the watts. Since electrical meters measure volt-amps, and you get billed for volt-amps instead of watts, some portion of your energy bill may be for power that you did not actually consume. In large installations, this can represent a sizable dollar amount. Power factor correction, which reduces the reactive portion by adding capacitance to counter the inductance (or by adding inductance if your loads appear capacitive) will tend to make the volt-amp product equal the watts, and thus lower your energy bill.
