Power Capacity of High Voltage Cables for Future Electrical Aircraft

Efforts to reduce CO2 emissions from future electrical aircraft have focused on improving fuel efficiency by replacing hydraulic and pneumatically powered systems with electrically powered components. Voltage and current levels continue to increase to support the increased demand for electric power. The frequency level is also high in some parts of the AC system. This paper describes the analysis carried out to understand the power rating of screened and unscreened cables under various AC frequency and pressure conditions. It is found that increasing frequency and decreasing pressure can lead to a decreasing current capacity due to skin effect and a reduction of convective heat transfer coefficient respectively. Moreover, screened cables are shown to be particularly advantageous in an aerospace environment given the higher withstand voltage and the slightly improved thermal performance. The results will deliver improved guidance in the current rating design of high voltage cables applied in an unpressurised environment.