Power Disturbance and Quality: Light Flicker Voltage Requirements

Emphasis on power quality has brought renewed attention to the old subject of light flicker. There is a need to review the technical basis for flicker tolerance curves used as guides to satisfactory installations. More or less frequently recurring low-amplitude voltage disturbances can cause electric lights to flicker. Light flicker voltage requirements prescribe the maximum permissible voltage fluctuations the system can tolerate without annoying light flicker. These limits on allowable voltage fluctuations are the topic of interest to power systems engineers, more so than the broader subject of light flicker. The author discusses the historical perspective of light flicker and permissible voltage fluctuations. The effect of such fluctuations on light flicker and the symptoms associated with flicker are then discussed. Human vision aspects of light flicker are also discussed.