Flicker impact on 150 W HPS Lamps of different ages

The IEC has standards covering both a flickermeter and a flicker definition. These documents have been adopted in Europe by the CENELEC as EN norms. 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 measured according to IEC 61000-4-15 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 flickermeter should be different for each type of illumination technique in order to provide accurate information about flicker phenomena. At the same time, lamp age also plays an important role in flicker generation. The above are the main objections given for not adopting the IEC flickermeter in countries as USA. 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.