In recent years the way electricity is used has changed significantly. Developments in semi-conductor technology have created a major increase in thyristor and converter-fed loads. Electronic equipment, particularly that using solid state devices, can have a detrimental effect on the electrical power system in a facility to the point where operation of electrical and electronic equipment is disrupted. Solid state devices generate Harmonics into the electrical system, i.e. they generate frequencies that are integer multiples of the fundamental line frequency of 60 Hz. The harmonics lead to a higher capacitor current, because of the higher frequencies that are attracted to the capacitor. The impedance of the capacitor decreases as the frequency increases.

Harmonic distortion can result in any or all of the following: