Impedance of 400-cycle three-phase power circuits on large aircraft and its application to fault-current calculations

THE use of 200-volt three-phase 400-cycle a-c systems in large aircraft, with multiple circuits fused for fault clearing of sections, requires an accurate analysis of fault currents at all points of the system. A preliminary investigation of impedance data for 400-cycle aircraft circuits disclosed that basic data were available for certain types of impedance, but that certain impedance values required for line-to-ground faults were completely lacking. The object of this report is to complete the impedance data and to present in one complete compilation all impedance data required for analysis of faults in 400-cycle grounded-neutral aircraft systems as now proposed.