Effects of Flicker on Different Types of 150-W High-Pressure Sodium Lamps and Ballasts

The limits of the severity of flicker caused by voltage fluctuations is defined in Europe by the standard CENELEC EN 50160. Under normal operating conditions, flicker level will not exceed the long term severity P_lt=1 during 95% of the time in one week. This threshold was originally established considering that a lamp with tungsten coiled coil filament of 60 W and 230 V that is gas-filled produces a flicker perceivable by 50% of the population when it is supplied with a voltage that verifies P_lt=1. Other light sources like fluorescent lamps and discharge lamps with ballasts exhibit a different behavior under the same supply conditions. This means that the flicker meter should be different for each type of illumination technique ir order to provide accurate information about flicker phenomena. At the same time, lamp age also plays an important role in flicker generation. In this research work, a test system and a methodology able to measure the optical fluctuation produced by different types of lamps and ballast is presented. This experimental platform allows to obtain a correlation between voltage flicker levels and optical flicker perception. It can be considered the first step in the definition of new lamp models. This work also shows that age lamp has a significant correlation with flicker generation.