A power plant experienced unexplained trips in its gas-insulated switchgear (GIS). Visual inspections found nothing wrong, so the team brought in a partial discharge tester. Using an ultrasonic sensor, they detected abnormal discharge signals originating from a specific compartment. Further investigation revealed a loose connection causing a localized electric field concentration. The discharge had been eroding the insulation over time, which could have led to a catastrophic failure. The PD test data allowed the maintenance team to target the exact location for repair, saving weeks of unnecessary disassembly and avoiding a shutdown that would have halted the entire plant’s production.
Using PD Testing to Diagnose Hidden Insulation Defects in GIS Switchgear
May 12, 2026
