Analysis and Experimental Validation of SSTDR for Simultaneous Distributed Diagnosis of Wire Networks

Reflectometry -based techniques such as Spread Spectrum and Sequence Time Domain Reflectometry (S/SSTDR) have been used extensively for the detection, localization, and characterization of electric faults in wires. However, in branched wire networks, testing using a single sensor suffers from ambiguity, where it can be difficult to determine which branch contains the fault. Distributed reflectometry, which uses multiple sensors to test the network from different locations, can resolve this ambiguity. This paper evaluates pseudo -noise (PN) and zero correlation zone (ZCZ) codes for simultaneous distributed testing. Maximum length (ML or m-), Gold and zero correlation zone (ZCZ) codes are compared for a set of up to 16 simultaneous sensors. ML and Gold codes show significant interference between sensors, but the ZCZ codes show near -zero interference over their measurement zone. This lack of interference greatly enhances their use for locating faults. The results were verified numerically and experimentally.