The high capacity arc furnaces connected to the high voltage level create fluctuations in source voltage at the point of common coupling. These voltage fluctuations then propagate throughout the power system to the low voltage level, with different degrees of attenuation. The propagation of voltage flicker in the power system requires real practice measurements on which the analysis of customer perturbation levels is evaluated. The case study deals with the analysis of flicker perturbation level, respectively short term flicker index Pst and long term flicker index Plt, within a customer area.