On-line partial discharge applications to MV electrical switchgear

Industry has been exposed to partial discharge technology, related to generators, for many years. A switchgear manufacturer has invested in the advancement of partial discharge technologies related to the on-line analysis of insulation systems for MV switchgear. Partial discharge testing has been completed on both new MV switchgear in the factory setting, as well as several older field installations. The results clearly indicate that partial discharge analysis of MV switchgear is an excellent on-line predictive maintenance tool. It has also been found that older MV switchgear designs are prone to internal corona activity. The majority of existing plants contain MV switchgear of a very old design, therefore the use of on-line PD analysis can identify areas of immediate concern. This paper reviews the applications to MV switchgear. Actual examples of pending failures, which were identified by on-line partial discharge measurements, are presented. This new application of partial discharge technology can greatly aid in the day-to-day reliability and life-extension of MV electrical equipment.