Influence of Aircraft-Environment Pressure Range on Negative DC Partial Discharge Inception Voltage

The increasing greenhouse gas emissions have a huge impact on global temperature. The aviation sector contributes to 2.4% of the global CO
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emissions and more than 10% of the transportation emissions are from commercial airplanes in the US. To combat the climatic changes, the goal to achieve net zero emissions by 2050 was set and complete electrification of transportation is one of the many steps in realizing that goal. The aviation sector started the electrification of aircraft starting from more-electric aircraft (MEA), and the allelectric aircraft (AEA) are not too far in the future. While MVDC in a few kVs range has been targeted for AEA electric power systems (EPS), there are several challenges when dealing with higher voltage in the kV range under low pressures for AEA that need to be addressed including partial discharges (PD) under DC stress. It is important to understand the PD behavior beforehand while designing the air insulation for EPS components. This study aims to understand the PD behavior of air under an aviationenvironment pressure range and to provide insights into the variation of partial discharge inception voltage (PDIV) with different gap distances for a sphere-sphere electrode geometry. PD behavior was studied under a negative DC voltage for flight-level air pressure and a peculiar pattern in PDIV was observed for different pressures and interelectrode distances.