Light intensity variation (flicker) and harmonic emission related to LED lamps

•This paper studies the light intensity variations (potentially leading to light flicker) due to variations in voltage magnitude over domestic LED lamps.•The normalized gain factor is used to compare variations in light intensity for different lamps in an objective way.•The relation between the normalized gain factor and other power quality indices, such as DPF, total PF, and active power has been studied and is discussed.•Some of the LED lamps show more sensitivity to voltage magnitude variations for at least one modulation frequency compared to the incandescent lamp.•The measurements shown here indicate that while improving the LED lamps performance regarding harmonic emission, the performance for flicker susceptibility becomes worse. This paper discusses two power-quality aspects of LED lamps: harmonics and flicker. Measurements have been performed of 24 different LED lamps: the harmonic current spectrum and light intensity variations have been measured. To enable an objective comparison, the light intensity variations were measured for all the lamps when exposed to the same voltage magnitude variations. Results show a large variety in harmonic emission between different LED lamps indicating that different technologies or different components are being used within the LED lamps. Moreover the results show a large variety in light intensity variations when different LED lamps are subjected to the same voltage fluctuations. A clear correlation was found between harmonic emission and sensitivity to voltage magnitude variations. Lamps with low light intensity variations are also the ones with the highest harmonic current emission. No clear relation between active power or price and sensitivity to voltage magnitude variations was found.