Surface discharge behaviors of high temperature insulation subjected to gas pressure variations in hybrid propulsion systems

fluoropolymer based high temperature insulation materials having excellent thermal, mechanical and dielectric properties are used in power distribution system in aerospace and marine application and hence subjected to aging under harsh environmental conditions. Surface discharge as a known deteriorating factor on these materials has been investigated in this work. Discharge behavior during pressure changes from ambient pressure down to 20kPa has been studied on two fluoropolymers (PTFE, FEP) and a high performance aromatic polymer (Kapton-CR). Main PD data including number of detected pulses, time interval between PDs, magnitude, average of PD charge, accumulative recorded PD charge, and equivalent time-frequency parameters of PD waveforms have been extracted and presented for fixed positive DC voltage values (2, 4, and 6 kV). The content of this paper could be of great significance for the development of new hybrid thrusters for aircrafts.