The work presented focuses on voltage fluctuations produced by household devices and their impact on the light output of LED lamps. Voltage fluctuations can produce unsteadiness on the light intensity of the lamps, so-called light flicker. An observer may or may not experience light flicker, depending on e.g., the severity of the voltage fluctuation, the lighting technology affected and the characteristics of the observer itself. The presence of voltage fluctuations in the grid is limited in the standards. One of the reasons for this limit is the impact the voltage fluctuations have on an incandescent lamp and by the irritability experienced by an average observer experiencing the resulting light flicker. New lighting technologies have been developed replacing the incandescent lamp e.g., halogen lamps, fluorescent lamps or most recently LED lamps. LED lamps are already in the market and are expected to dominate it in the future years.

The impact that voltage fluctuations produce on LED lamps is studied in this thesis. To address this study, the factors other than voltage fluctuations that could affect the light output of LED lamps are studied, e.g., stabilization of the LED lamp, topology, impact of aging on the LED lamp or ambient disturbances.

The study is focused on the voltage fluctuations produced by household devices. Measurements of household devices are performed to characterize the voltage fluctuations that they produce by e.g., their magnitude, rate of change, frequency or perception level by an average observer of light flicker on LED lamps.

Different LED lamps have different responses on the light output subjected to a similar voltage fluctuation. This is a difficulty when considering LED lamps as a reference to measure their ritability experienced by an observer due to voltage fluctuations. The study offers a solution based on the characterization of the response of a generalized LED lamp.

Uncertainties, such as the use of household devices or the occurrence of voltage fluctuations, are addressed using a stochastic approach, introducing the concept of risk to light flicker. Therefore, stochastic assessments of the risk and severity of light flicker are performed in a low voltage grid at different points of evaluation considering the propagation of voltage fluctuations between customers. In addition, the results of the severity of light flicker considering the response of a generalized LED lamp are compared to the severity obtained with an incandescent lamp.