How to specify power-quality-tolerant process equipment

While power quality is basically voltage quality, it is not strictly a voltage issue. Since the supply system has a finite, rather than an infinite, strength, currents outside the direct control of the utility can adversely affect power quality. These are harmonic load currents, lightning currents, and fault currents. How do we quantify voltage aberrations indicative of power-quality problems? One must employ an accurate voltage-measuring device, such as an oscilloscope, to identify which of the voltage aberrations, discussed in the article, is causing the problem. Equipment to mitigate the power quality problems is discussed. The acquisition of new equipment from the power quality perspective is also discussed and a checklist of procedures for design, installation and testing is given.