A high-impedance fault detection scheme for DC aircrafts based on comb filter and second derivative of voltage

Faults in a DC aircraft power system typically lead to serious equipment damage, which severely threatens the safety of the whole aircraft system. A fast and accurate real-time fault detection scheme is necessary for aircraft power systems to provide high reliability in the system. In this paper, a new fault detection device (FDD) is proposed based on the comb filter and second derivative of the system voltage to detect both low and high-impedance faults (HIFs) in a fast way. The proposed method utilizes the comb filter in the middle of the two first derivatives to detect both high and low-impedance faults within several microseconds. For demonstrating the efficiency, authenticity, and compatibility of the proposed method, digital time-domain simulations are carried out and verified by real-time simulations using an OPAL-RT simulator under different scenarios such as low- and high-impedance fault, overload, and motor starting to verify distinguishing between non-fault disturbances and faults. The results, which are compared with reported methods, prove the accuracy and speed of the proposed FDD in a DC aircraft.