Fluorescent lamp modelling for voltage fluctuations

The wide use of fluorescent lamps means their influence on the power system needs to be studied. A set of models that enables the evaluation of the electrical behaviour during steady state is presented in this paper. These models have different levels of complexity; starting by taking into account all the non-linearities of the lamp, passing through neglecting the non-linearities of the reactance, supposing the voltage wave shape of the tube to be square and, finally, treating the variations in the RMS source voltage as an steady-state phenomenon. The most complex model needs an iterative algorithm to get results, however analytical expressions can be achieved with the other models. Several situations can be analysed with the different models but special attention is paid to the sinusoidal voltage source and the modulated voltage source cases. Also, the study presented in this paper is focused on obtaining the waveshape of current, voltage and power in the tube. These waveforms allow the study of the normal steady-state functioning and the flicker phenomena. In this paper the simulation results for the above models in the two kinds of situations are shown. As a result, a performance test between the models is made and it is used to validate them.