The harmonic solution
Harmonics are a serious problem and cannot be ignored for a variety of practical and legislative reasons.
In identifying the problem, probably one of the toughest tasks is taking measurements. However, analyser instruments are available for purchase, or hire, and quite a few specialists will make assessments for you. Actually remedying harmonics is in most cases simply a matter of fitting the correct filters.
One of the easiest, most practical and common solutions is to install line reactors. These devices introduce an impedance that reduces the root mean square (RMS) and peak voltages while at the same time improving the power factor. It is possible to combine such a reactor with a conventional filter in a single unit, thereby providing attenuation for the mains borne interference and compliance with the EMC Directive (an earlier enacted legislation covering electro magnetic and radio frequency interference). By incorporating both of these necessities in a single housing, valuable panel space is saved and wiring is minimised.