Analysis of factors contributing to unexplained transmission line faults on a high voltage transmission network

This paper describes the results of an investigation into various fault mechanisms that may occur on the South African high voltage network. A large percentage of the recorded faults are often attributed to unknown causes. The analysis of the fault data presented in this paper indicates that many of these faults may be ascribed to known fault mechanisms. Time of day analysis coupled with time of year analysis is shown to be a useful tool in ascribing probable causes to these faults. Case studies for three particular lines are presented.