High-frequency current sensor for power network on-line meaurements

High-frequency transients in power distribution networks can be caused by faults or this may be indication of soon to happen breakdown of isolation. In many cases monitoring and precise measurements of the high-frequency phenomena can help to determine location of fault on the line, but also lead to discovery of problematic component prior to breakdown. Equipment available in distribution substations today is not capable of monitoring such high-frequency signals. In this paper a current sensor for detecting fault and pre-fault high-frequency transients is proposed. Requirements for such a sensor are presented and a sensor design meeting the requirement is carried out. Topics regarding sensor bandwidth and sensitivity are discussed.