Monitra's HFCT sensors are inductively coupled around the MV/HV cables to provide a means for partial discharge (PD) measurements to be made on in-service cables, transformers and rotating machines.

Each sensor inductively measures the high frequency current signals within the PD pulses flowing in the earth or the conductor of the cable without the need for any direct, galvanic connection to the HV.

The sensors can be installed permanently during a planned outage or at the build stage of a project to enable on-line PD monitoring or routine spot testing.

A temporary installation of the HFCT sensors can be carried out without an outage if the cable earth is available outside of the termination box, enabling on-line PD spot testing without the need for permanent sensors or an outage.