Corona Inception and Breakdown in High-Altitude, Low-Pressure Air under Negative DC Voltage for Aircraft Electrification Applications

The achievement of the net-zero emission goal is considered contingent upon the implementation of transportation electrification. Presently, all-electric commercial vehicles are restricted to land and water transport. The prospect of complete electrification of aircraft, particularly the plausible realization of all-electric aircraft (AEA), is acknowledged as being imminent. Within the electric power system (EPS) designs proposed for AEA, medium DC voltage systems in the order of up to a few tens of kilovolts are employed. Challenges manifest in the management of such voltages within a low-pressure environment. One of the emerging challenges pertains to the partial discharge (PD) behavior under DC stress, a phenomenon acknowledged to exhibit pressure- and field-dependent variations. The importance of studying the dynamics of pre-breakdown and breakdown phenomena in such environments is underscored by the fact that air serves as a crucial insulator for the EPS in AEA. Accordingly, this experimental study aims to comprehend the behavior of air subjected to high negative DC voltages and offer insights into the PD onset dynamics, specifically corona inception and breakdown. This investigation utilizes a needle-to-plane electrode configuration, examining its performance under a standard range of aviation-specific pressures across varying air gaps. The findings of this study contribute to the development of reliable electrical insulation systems tailored to withstand the demanding conditions encountered during aircraft operation.