Partial Discharge Testing (PD Testing) Services

A partial discharge (PD) is an electrical discharge or spark that bridges a small portion of the insulation between two conducting electrodes. PD can occur at any point in the insulation system, where the electric field strength exceeds the breakdown strength of that portion of the insulating material such as in voids within solid insulation, across the surface of insulating material due to contaminants or irregularities, within gas bubbles in liquid insulation or around an electrode in gas (corona activity).

Online Partial Discharge Testing is used to verify proper working condition of electrical insulation components in high voltage equipment.  The testing methods are non-invasive and performed on live equipment without the need for an outage. Each electrical device is inspected using UHF, HFCT, Ultrasonic, Acoustic, and TEV measurements.

ASSETMATRIX utilize state-of-the-art electromagnetic sensors and analysis techniques from renown and specialists’ manufacturers which are more sensitive than conventional methods.  

Advantages of PD Testing Services

Non-Invasive approach does not risk the device under test.

No outage required. Test is performed on live equipment during normal service.

Verify the health and proper working condition of high voltage insulation components. 

Identify incipient faults.

Identify insulation deficiencies which cause pre-mature degradation.  

Reduce or defer unnecessary maintenance and prioritises urgent maintenance.  

Over 85% of disruptive failures in medium voltage (MV) & high voltage (HV) equipment are Partial Discharge related. PD Survey and Testing can be carried out on a wide range of equipment such as: Transformers, Bushings and Insulators, Breakers, SF6, Vacuum Bottles, Cables, Splices and Terminations, CT’s, PT’s, Lightning Arrestors, Switches, Bus, Metal-Clad Switchgear, Electric Motors, Generators and Alternators

Once PD activity starts it inevitably leads to failure. PD activity provides clear evidence that an asset is deteriorating in a way that is likely to lead to failure. The process of deterioration can propagate and develop, until the insulation is unable to withstand the electrical stress, leading to flashover. The ultimate failure of HV/MV assets is often sudden and catastrophic, producing major damage and network outages.

Our PD testing service requires no shutdown and is an ideal way to plan maintenance, repair or replacement activities in a cost effective and efficient manner. ASSETMATRIX will provide an Online Partial Discharge Test Report for each device under test after the PD Survey listing any problems found and corresponding recommendations. Each device will be tested using UHF, HFCT, TEV, ultrasonic and AE sensors where applicable. The measurement values and phase-resolved charts are recorded and associated with the device under test.