Autonomous current sensing for high voltage systems with auxiliary optical energisation

An autonomous sensing system is described for deployment on high voltage power lines and to provide an economical method for monitoring current on such lines. The autonomy is provided by drawing power off the line being monitored via electromagnetic induction to drive the current measuring device and for the transmission of the current data to ground level via an optic fibre link, which provides inherent electrical insulation. When the autonomy of the system is threatened, the system automatically switches to be energised from a laser source at ground control via a second optical fibre link. Test results showing the performance of the system are presented.