Partial Discharge Characteristics Of Perfluoroalkoxy Insulated Cables For Aircraft Power Systems Under AC Voltage At Different Pressures

Abstract

Reduced pressure at high altitude increases the susceptibility of aircraft cabling systems to partial discharge (PD) activity, which can accelerate insulation degradation and threaten system reliability. In this work, a high-voltage AC test platform (up to 10 kV) was integrated with a pressure-controlled chamber adjustable from 10 to 100 kPa. Phase-resolved partial discharge (PRPD) measurements were performed on perfluoroalkoxy (PFA) insulated aircraft cables designed for middle voltage aircraft power distribution systems. Experiments were conducted under reduced-pressure conditions at fixed normalized voltage levels. The measured parameters include partial discharge inception voltage (PDIV), partial discharge extinction voltage (PDEV), the repetition rate (RR), mean discharge magnitude, and phase span. The results reveal a clear pressure dependence of discharge activity, magnitude distribution, and phase characteristics. Reduced pressure leads to increased discharge activity and stronger discharge events due to enhanced ionization efficiency. The obtained PRPD feature trends provide insight into the pressure-dependent PD behavior of PFA-insulated aircraft cables and contribute to insulation design, reliability assessment, and monitoring strategies for electrical systems in future electric aircraft.