Helping to highlight a hidden hazard

Partial discharge arising from localised defects in insulation is the primary cause of system failure in electrical distribution equipment, accounting for up to 90% of electrical failures, according to HVMS. Sporadic in nature, such discharges may remain undetected for some time, eventually developing into unexpected system failures, with potentially severe consequences.

Partial discharge refers to the electrical discharge or spark which can occur between two conducting electrodes along a section of insulation, typically in ageing cables or defective joints and terminations.

The accumulation of energy from partial discharge gradually weakens the insulation, leading to a system malfunction.

Martin Avis, operations manager, says "People are put off by what they imagine to be an expensive and time-consuming process. For most facilities, periodically carrying out a partial discharge survey is a relatively inexpensive exercise when compared to off-line testing. The sophisticated equipment we use means the test procedure is non-intrusive and does not require a power outage".

HVMS recommends annual testing, especially for critical plant.