Modelling the dynamic interaction «Power System – Lamp». application to high pressure mercury Gas-Discharge Lamps

The aim of this paper is to study the dynamic behaviour of a plant constituted by an electrical power system and a gas discharge lamp; this latter, increasingly used in street lighting, remains a nonlinear load element. Various approaches are used to represent it, one is the approximation of the discharge represented by a hot "channel", which verifies the assumption of local thermodynamic equilibrium [LTE] or the polynomial form of the conductance variation. A calculation procedure, based on “channel” approximation of the high pressure mercury (HPM) gas-discharge lamp, is developed to determine the physical and electric magnitudes, which characterize the dynamic behavior of the couple "lamp– electrical power system". The evolution of the lamp properties when principal parameters of the discharge (pressure of mercury, voltage supply, frequency) are varying were studied and analyzed. We show the concordance between simulation, calculations and measurements for electric, energetic or irradiative characteristics. The model reproduces well the evolution of properties of the supply when principal parameters of the discharge vary.