Electrical protection solutions enabling integrated electrical power and composite structure systems for aircraft

The combined dual trends for increased use of electrical power for more-electric aircraft (MEA) and carbon fibre reinforced polymer (CFRP) for light weight aircraft structures have been pursued to improve overall aircraft efficiency, reducing fuel burn and hence emissions. However, due to the poor electrical conductivity of CFRP, the CFRP structure and electrical power system (EPS) must be kept physically separate via bulky, heavy cable harnesses and raceways. The closer integration of EPS with CFRP structure offers an opportunity to optimize the weight and volume of the combined electrical power and structural systems, reducing the need for harnesses and raceways. To enable this, there is a need to understand the implications that this will have for electrical power systems design, including approaches to protection. This paper identifies candidate protection solutions for resilient, integrated electrical-composite aircraft structures, by consideration of the interdependent trades between MEA EPS architecture design, CFRP, grounding topology, and electrical fault response. The influence of these interdependent elements on protection requirements is explored, and as a result, design rules for the protection of such resilient, integrated systems are formulated and presented, enabling a focus on the fault response of the system and development of appropriate protection solutions.