Research of the Negative Influence of Dimmed LED Luminaires in Context of Smart Installations

Abstract

This article deals with the investigation of the negative impacts of dimmed public, industrial and office LED (light emitting diode) light installations. This approach is required due to the uncertain design of LED ballasts, while manufacturers do not implement the required PFC (power factor correction) function. Therefore, the focus is on a brief description of the principles of negative influences such as: low power factor, high inrush current and high total harmonic distortion based on direct confrontation with actual standards (IESC EN, NEMA, ENERGY STAR). Further, the behavior of LED drivers is explained under nominal load and dimmed up to critical level. Presented findings confirm issues reported by users from larger installations where LED fittings are dimmed over a certain level. The article includes recommendations for consumers and producers of LED fittings about main issues from the scientific and user points of view. Presented facts conclude on the necessity of studying the marginal operating state of LED fittings aiming at THD (total harmonic distortion), PF (real power factor) and inrush currents.

Study on the Power Quality of LED Street Luminaires

“…The research concludes that dimming the LED luminaires can pose power quality issues, especially increasing capacitive reactive power and harmonic current distortion. The tests performed in [29] show that, in the case of LED street luminaires, the low THDI (total harmonic current distortion) values at the nominal luminous flux are also maintained at levels of dimming up to 70% of the nominal luminous flux (with increased values of THDI up to 20%). This will cause only a small negative impact on the supply grid.…”