Nonlinear Model of Fluorescent Lamp in Harmonic Studies

A specific source of harmonic currents in power grid are fluorescent lamps with electromagnetic ballast. A new model of fluorescent lamps with electromagnetic ballast is presented in this paper. Also, applicability to simulations of fluorescent lamp performance for steady state source voltages and for its RMS time variations with nominal frequency is also demonstrated. The presented model is based on an extended curve fitting procedure against to the existing standard fluorescent lamp models. For the approximation of the lamp's i-u characteristic, a pair of exponential functions representing the fluorescent lamp branches is chosen. The obtained simulation results were verified by comparison against the measurements and an excellent agreement was found. It is also demonstrated that the suggested fluorescent lamp model delivers accurate results for different steady state source voltages including its variations. The presented and suggested lamp model can be efficiently used in harmonic studies and its implementation in the existing EMTP/ATP or MATLAB/SPS simulation tools is straightforward.