On-line Partial Discharge Spot Tester



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Handheld Partial Discharge Spot Tester

The PD-SGS is an on-line partial discharge spot tester for HV assets. The instrument detects TEV signals generated by internal discharge in Air Insulated Switchgear (AIS), acoustic discharge generated by surface tracking or corona, high frequency signal generated by cable partial discharge, and ultra-high frequency signal generated by internal discharge in Gas Insulated Switchgear (GIS).

  • Measurement of TEV signals generated by internal AIS PD
  • Ultrasonic detection of surface PD activity
  • Compatible with HFCT and UHF sensors for cable and GIS PD activity
  • Automatic Background Noise Separation
  • Level Mode and PRPD Mode
  • Bright OLED screen display with dB readings
  • Audible output through headphones or built in speaker


Switchgear – Air Insulated (AIS)

Partial Discharge activity inside metal clad high voltage plant induces small voltage impulses called Transient Earth Voltages on the surface of the metal panels. TEVs travel around the surface to the outside of the switchgear, where they can be picked up externally using the PD Detector.

Defects on the surface of high voltage insulators are prone to a phenomenon known as surface tracking. Tracking causes carbon deposits that build up over time, ultimately leading to flashover and insulation failure. The PD Detector is highly sensitive to the ultrasonic emissions produced by tracking and enable the onset to be detected before insulation failure.


Switchgear – Gas Insulated (GIS)

IPEC’s UHF (Ultra High Frequency) sensor is used to detect PD in EHV cable terminations, GIS (Gas Insulated Switchgear), GIL (Gas Insulated transmission Lines) & GIT (Gas Insulated Transformers). The sensors pick up signals in the UHF range (200MHz-2.0GHz) and are mounted against the insulating barrier spacers that separate components of the HV asset.



Partial discharge activity in solid high voltage insulation induces small high frequency currents in the earth conductor of the electrical system. These impulses travel along the equipment earth to the substation earth. Using a high frequency current transformer, they can be detected as they pass through the CT.


Advantages of the PD-SGS

  • Rapidly survey the whole substation – and detect MV and HV problems before they occur
  • Personnel Safety Device – ensure the substation is clear of PD before conducting work
  • Hear the PD – only instrument available that allows the user to hear  PD activity
  • Ensure accurate results – auto separation when the device detects background Noise instead of real PD
  • Ergonomic and compact design – fits in the user’s pocket and Is easy to use
  • Long lasting battery – allowing a whole day of testing without requiring a recharge


Accessories: Ultrasonic Parabolic Dish

 The Parabolic Reflector is an ultrasonic sensor for use when detecting partial discharge activity on exposed insulating surfaces. The reflector increases the sensitivity of the sensor allowing detection to be effective at up to 25m. It is commonly used in outdoor switchyards to detect surface discharge on string and post insulators, sealing ends and other exposed equipment.