Design and Analysis of Medium Voltage DC Cable Ducts for Electric Aircraft Considering Thermal and Electrical Insulation Requirements

Power cables are essential components of the electric power system in future all-electric aircraft (AEA). The AEA operates under varying conditions, with a maximum power requirement of 25 MW during takeoff at atmospheric pressure and 7.5 MW during cruising at low pressure (18.8 kPa). Optimizing the design of both cables and ducts for minimal weight and size is crucial for enhancing system performance. At cruising altitudes, power cables experience significant thermal challenges due to reduced convective heat transfer. In addition, they face electrical issues such as partial discharges (PDs) and arc tracking. To mitigate these challenges, multilayer multifunctional electrical insulation (MMEI) systems have been developed in our prior work. In this study, we utilize COMSOL Multiphysics to analyze MMEI-insulated cables under three different duct configurations: rounded rectangle, cylindrical with vertically oriented cables, and cylindrical with horizontally oriented cables. The analysis is conducted for two operational conditions: 450 A at 18.8 kPa and 1000 A at 101.325 kPa. Our results demonstrate that the rounded rectangle duct achieves the best balance between weight and area, offering the lowest total weight and cross-sectional area among the three configurations. The cylindrical duct with vertical cables shows a slightly higher weight compared to the horizontal configuration, but exhibits comparable thermal performance. The cables were electrically analyzed and satisfied the required operational conditions. These findings offer valuable guidance for designing lightweight, thermally efficient cable duct systems for AEAs.