HFCT – High Frequency Current Transformer

HVPD's range of wideband, High Frequency Current Transformer (HFCT) sensors are used to measure partial discharge in power cables and in remotely connected HV plant such as rotating HV machines and transformers. The sensors are attached around the cable's earth connections in the switchgear, rotating machine or transformer's HV cable terminal box.


Permanent HFCT sensors are installed inside the HV cable box (of the switchgear, transformer or rotating machine) to enable OLPD testing and/or monitoring of in‑service MV/HV cable circuits without the need for an outage. We also supply Ex/ATEX versions of this permanent HFCT sensor for use in hazardous gas zones in the oil & gas industry. 

Portable, split-core HFCT sensors are used when the earth connections of the HV cable are outside of the cable box. The sensors can also be installed inside the de‑energised and isolated cable boxes of switchgear, transformers or rotating machines for temporary testing or monitoring if the earth connections are not available outside the cable box (requires an outage). 


Permanent Installation Kit


3-phase, permanent HFCT sensor installation kits are ideal in situations where MV/HV plant outages are rare. The kit includes three HFCT sensors with silicone mounting collars, TEV sensor, sensor terminal box and all accessories.

Ex/ATEX Installation Kit


Our Ex/ATEX HFCT Sensor Installation Kit is suitable for installation in hazardous, explosive gas environments. The kit includes three Ex/ATEX-rated HFCT sensors with silicone mounting collars, signal cables, Ex/ATEX‑rated sensor terminal box and all accessories.

Silicone Mounting Collars


HVPD use carefully selected silicone mounting collars with our permanent HFCT sensors to provide both electrical isolation from the cable under tests, and also as a mechanical fixing – to secure the HFCT sensors in place on the HV cable termination.


High Frequency Current Transformers

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Product HFCT100HFCT100.jpg HFCT140HFCT140.jpg HFCT220HFCT220.jpg
Internal Aperture 45 mm 94 mm 140 mm
External Aperture 110 - 150 mm 180 mm 237 mm
Installation Type Portable & Permanent Portable & Permanent Portable & Permanent
High Current Version      
Aluminium Housing Version (For improved screening from RF noise)      
Outdoor Version      
Ex/ATEX Certified Version      
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Yes   No