Partial Discharge (PD) Diagnostics is a non-destructive testing method used to detect and analyze localized electrical discharges that occur within the insulation of high-voltage equipment. These discharges do not completely bridge the electrodes but are a sign of insulation degradation that can lead to eventual failure if left unaddressed.
PD diagnostics is essential for assessing the condition of critical components such as:
Power transformers
High-voltage cables
Gas-insulated switchgear (GIS)
Rotating machines (motors and generators)
Bushings and insulators
Partial discharges are typically caused by voids, cracks, moisture, contamination, or manufacturing defects in the insulation material. If not detected early, they can grow over time and result in complete insulation breakdown.
Key techniques used in PD diagnostics include:
Ultrasonic and acoustic emission detection
Electromagnetic (HF/VHF/UHF) measurements
Oscillating Wave Testing (OWT)
Online and offline monitoring systems
Benefits of Partial Discharge Diagnostics:
Early fault detection before insulation failure
Improved asset reliability and lifespan
Reduced risk of unplanned outages
Compliance with IEC, IEEE, and other standards
Regular PD testing helps companies optimize maintenance schedules, ensure the safe operation of high-voltage systems, and avoid costly breakdowns.
