Intermittent Arc Fault Detection And Location For Aircraft Power Distribution System

Abstract

This thesis addresses a non-destructive diagnostic method for intermittent arc fault detection and location. Intermittent arc faults appear in aircraft power systems in unpredictable manners when the degraded wires are wet, vibrating against metal structures, or under mechanical stresses, etc. They could evolve into serious faults that may cause on-board fires, power interruptions, system damage and catastrophic incidents, and thus have raised much concern in recent years. Recent trends in solid state power controllers (SSPCs) motivated the development of non-destructive diagnostic methods for health monitoring of aircraft wiring. In this thesis, the ABCD matrix (or transmission matrix) modeling method is introduced to derive normal and faulty load circuit models with better accuracy and reduced complexity compared to the conventional differential equation approach, and an intermittent arc fault detection method is proposed based on temporary deviations of load circuit model coefficients and wiring parameters. Furthermore, based on the faulty wiring model, a genetic algorithm (GA) is proposed to estimate the fault-related wiring parameters, such as intermittent arc location and average intermittent arc resistance. The proposed method can be applied to both the alternating current (AC) power distribution system (PDS) and direct current (DC) PDS. Simulations and experiments using a DC power source have been conducted, and the results have demonstrated effectiveness of the proposed method by estimating the fault location with an accuracy of +/- 0.5 meters on 24.6 meters wire. Unlike the existing techniques which generally requires special devices, the proposed method only needs circuit voltage and current measurement at the source end as inputs, and is thus suitable for SSPC-based aircraft PDS.