Energy-based comparison of military standard high-voltage waveforms in testing of aerospace vehicles

Abstract

Aerospace vehicles undergo rigorous qualification tests to protect against lightning strikes. The military standard recommends subjecting test specimens to three specific high-voltage waveforms (types A, B and D). A comprehensive study analyses these waveforms regarding their energy content. Utilising experimentally obtained breakdown voltages (BDV) from the published literature, the magnitude of energy for specific time durations was computed for these waveforms in the present study. Type D exhibits the highest magnitude of energy, while its BDV is the lowest. The plot of the reciprocal of energies against their specific time durations resembles V-t characteristics of a typical insulation configuration. The magnitude of energy computed using equal voltage-peak for simulated waveforms exhibits a trend resembling the experimental results. Similarly, the computed voltage-peaks of these waveforms with equal energy are plotted as a function of time durations and resemble the experimentally obtained V-t characteristics. A waveform with higher energy content requires lower voltage-peaks from the breakdown point of view. This observation would help determine the voltage test magnitudes for the test waveforms specified in the military standard. This energy-based comparison, probably attempted for the first time, could lead to a critical evaluation and understanding of these test waveforms.