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).
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.
Over 85% of disruptive failures in medium voltage (MV) & high voltage (HV) equipment are Partial Discharge related. Once PD activity starts it inevitably leads to failure. 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.
Following the partial discharge survey a comprehensive PD Test report is issued, listing any problems found and corresponding recommendations.