Practical application of partial discharge testing of insulation systems with emphasis on medium voltage switch gear

Partial discharge measurements of insulation systems is a known indicator of the initial stages of insulation breakdown. Weak, damaged or aging insulation leading to breakdown almost always exhibit partial discharge caused by a voltage stress across that weakness prior to a complete breakdown. The partial discharge is a measurable event and through research, development and experience is a qualitative assessment of a impending total insulation breakdown.