A novel technique for measuring HVdc insulator leakage current using magnetic field sensors

Leakage current monitoring for high voltage transmission line insulators is of interest as it may be a key indicator of potential performance issues. High voltage direct current (HVdc) lines are more difficult to monitor when compared to alternating current lines as the conventional current transformers cannot be used to measure dc current. Presently, there is no commercially available, clamp-on type, non-intrusive devices for HVdc line insulator leakage current measurements. The South African power utility, Eskom, is currently investigating the development of such a hand-held sensor for two important applications. First, for continuous real time monitoring of HVdc line insulators and second, for use by live line workers to determine if it is safe to work on energised insulators. In this…