Statistical variation of wire parameters within complex aerospace networks

Abstract

This work evaluates the variation of wire impedance and velocity of propagation in bundled wires. Unshielded wire bundling was found to cause changes greater than 60Ω with standard deviation between 30.4–33.4Ω on 150Ω wires. Velocity of propagation was found to vary from 0.589c to 0.602c with a standard deviation of 0.0031c. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2082–2084, 2016

A SSTDR Methodology, Implementations, and Challenges

“…If these normal impedance changes are larger than the impedance changes from faults, they will mask the faults and make them invisible [ 7 ]. This variability has been measured for aircraft cable fault location [ 7 , 114 ] and PV systems [ 115 ]. Averaging multiple SSTDR signatures is particularly helpful when there are random impedance variations in the system.…”

“…In order to analytically evaluate how SSTDR will work in various PV arrangements, simulation engines have been developed to predict the SSTDR response. Three general methods have been used for this analysis—time domain solvers (e.g., the finite-difference time-domain (FDTD) method) [ 114 , 138 ], graph network theory [ 139 ], and frequency domain solvers such as the systematic solution procedure (SSP) [ 16 , 140 ]. Full simulations that consider the lengths and impedances of cables and elements within the system have been developed for PV [ 16 , 138 ], multiconductor transmission lines above a ground plane [ 141 ], ground faults [ 14 ], line-to-line faults, and open-circuit faults.…”