top of page
On-line Partial Discharge (OLPD) sensors

HVPD's range of OLPD sensors can detect dangerous partial discharge activity in cables (HFCT), rotating HV machines (HVCC or HFCT), switchgear (TEV or AA) and transformers (HFCT, TEV and Bushing Taps).


All HVPD's sensors are available in both portable and permanent versions, and supplied with complete installation kits. Permanent OLPD sensor installations are now becoming more popular in industries where plant outages are rare (the oil and gas industry, for example) to facilitate periodic OLPD diagnostic spot‑testing at any time, without the need for an outage. The installation, calibration and commissioning of sensor installations is always performed by HVPD's Installation Engineers.

High Frequency Current Transformer


HFCT sensors are used to measure PD in HV cables, rotating machines (up to 20 MVA) and cable-fed transformers. We offer the widest range of HFCT sensors for OLPD measurement in the marketplace, including fully EMC-screened versions, outdoor weather protected versions, high‑current (1000 A) versions, and Ex/ATEX‑certified versions

High Frequency Current Transformer
High Voltage Coupling Capacitor
High Voltage Couplng Capacitor

HVCC sensors are used to measure PD activity in the stator windings of HV generators and motors (from 3.3 kV to 30 kV). Our range of HVCC sensors have been tested to the voltage withstand and impulse levels as defined by the IEC and ANSI/IEEE standards. Ex/ATEX versions of HVCC sensors are also available.

Transient Earth Voltage
Transient Earth Voltage Sensor

The TEV probe is a high-frequency capacitive sensor that is used to detect local PD activity in metal‑clad MV switchgear. It is attached magnetically to the outside of the switchgear where it detects the transient earth voltages from the PD source. HVPD supply indoor and outdoor versions of the TEV sensor

Airborne Acoustic
Airborne Acoustic Sensor

The ultrasonic airborne acoustic (AA) sensor detects airborne acoustic signals from PD into air, including corona and surface discharges and tracking. The AA sensor is used in the HVPD's MV Switchgear Monitoring Solution with the HVPD Kronos™ Monitor and Linearplex AA Sensor Expansion Module

Smart TB-3 Sensor

The SMART-TB3™ is a world first, OLPD sensor for holistic plant condition monitoring of medium and high voltage (MV and HV) assets, including; rotating machines (direct or VSD-fed), switchgear and transformers.

Bushing Tap Adaptor Sensor
Bushing Tap Adaptor Sensor

The transformer bushing tap adaptor OLPD sensor can be used with portable OLPD test units and permanent OLPD monitoring systems to detect, measure and monitor partial discharge in HV/EHV transformers equipped with capacitive bushing taps.

bottom of page