Flashover Analysis of Near-Space Antenna Mounting Insulators

摘要

This paper discusses the problem of the flashovers of the insulators supporting long antennas in balloon flight applications. The antennas are to be operated in the stratosphere, where the low air pressure increases the risk of flashover. To analyze the problem, the Paschen’s law was applied to three thermodynamic data sets recorded during two different stratospheric balloon missions, launched in December and April 2015 (the April flight also with an experiment of additional heat-up due to solar radiation absorption). To estimate the influence of the humidity present in the cloud layers, a humid flashover case, previously investigated by the RCA on ground, was recalculated for stratospheric environment. The analyses show that the flashover voltage decreases rapidly with pressure-determined altitude and is higher for colder months of the year, which makes the system safer when operated at that time. Higher humidity reduces significantly the maximum flashover voltage, even the air gap remained three times larger than for the dry flashovers. Basic design requirements were formed for the stratospheric antenna mounting insulator in order to maintain the flight safety during high voltage operations.