Testing of fluorescent lamps for its flickering susceptibility towards interharmonic voltages

Light flickering was traditionally associated with incandescent lamps as the lamp luminance fluctuates with the RMS values of the supplied voltage. Fluorescent lamps, with ballast maintaining the current relatively constant, were largely regarded to be free of perceptible flicker. However, the increasing level of interharmonic voltages in the power systems has resulted in several reports of flickering by fluorescent lamps. This paper describes the results from an experimental investigation into the susceptibility of fluorescent lamps to flickering. The tests look into the three broad categories of fluorescent lamps widely in use, namely the conventional fluorescent tubes with separate magnetic or electronic ballasts and the compact all-in-one fluorescent lamps.