The quality of the mains voltage can be affected by voltage fluctuations, high-frequency interference, irradiation, noise, transientovervoltages, glitches, voltage dips and voltage interruptions as well as load fluctuations.
These influences have a direct impact on voltage-sensitive electronic circuits. For this reason, the electrical energy quality (EEQ) that a utility company must deliver at a defined transfer point is precisely specified. This applies not only to the mains voltage and its tolerances, but also to the mains frequency, its phase angles and signal purity.
If the electrical power quality of a mains voltage does not meet the required standards, it can be improved by means of dynamic voltage restorers (DVR) and, above all, line conditioners (LC).