Automatic fault location for underground low voltage distribution networks

This paper describes an automatic fault location technique for permanent faults in Underground Low Voltage Distribution Networks (ULVDNs). It uses signals from an existing Time Domain Reflectometry (TDR) instrument. It pre-processes TDR signals to eliminate reflections due to single-phase tee-offs, and to locate 3-phase open or short circuit faults and also uses adaptive filtering to compare the TDR signals to locate faults. In essence, the procedure minimizes the interpretation skill required from a user of a typical TDR based fault location instrument. The relative performance of the system is demonstrated using real field data.