Harmonic Resonance Stability of Aeronautical Ground Lighting Systems

Aeronautical ground lighting (AGL) systems assist aircraft pilots in airport operations. These systems are single-phase series circuits where constant current regulators (CCRs) feed luminaires with an adjustable rms current. CCRs are voltage-source converters (VSCs) which may cause harmonic resonance instabilities when their control interacts with poorly damped resonances in the 0.75-2.5 kHz range. This paper studies these instabilities from the impedance-based representation of AGL systems which are grid-connected VSC systems much simpler than that of the usual systems analyzed in the literature. This offers the possibility of contributing with a comprehensive stability assessment. Approximate expressions of the CCR and AGL circuit equivalent admittances are given to assess system stability. A comprehensive overview of the influence of AGL system parameters on harmonic resonance instabilities is presented, and several recommendations on the AGL system components and CCR parameters are proposed to improve stability. In addition, an active damping solution based on virtual conductances is analyzed. The expressions of the CCR admittance and some of the recommendations on CCR and AGL system parameters contribute to stability studies of grid-connected VSC systems. MATLAB/Simulink and PSCAD/EMTDC simulations of a 68-luminaire AGL system illustrate the contributions of this paper. Field measurements support the stability study.