due to electrical energy reduction need, in the recent years, alternative light sources like Compact Fluorescent Lamps (CFL) and Light Emitting Diode lamps (LED) are replacing the classical incandescent light bulbs. Although they consume less power, these lamps are a significant source of harmonics. This means that the lightning network should be redesigned taking into account the magnitude of the current harmonic components and of the null current. An accurate model easy to build and a fast analysis are very useful to this aim. This paper presents three models for a CFL, two existing ones and a new implementation, and a comparison from the viewpoint of validity range and simulation time. A frequency domain analysis is used to compute the periodic steady state response.