In this case study, Dynamic Ratings reports how online PD monitoring on 345 kV breaker bushings revealed abnormal discharge spikes that warranted further investigation. An on-site inspection using a solar-blind UV corona camera provided clear visual confirmation of active corona on multiple bushings—evidence of insulation breakdown that electrical measurements alone could not pinpoint.
The utility replaced the degraded bushings proactively, avoiding an unplanned outage and demonstrating the value of pairing continuous PD data with optical UV imaging. This combined approach strengthens diagnostic confidence, accelerates decision-making, and ensures that developing faults are captured before they evolve into failures.
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Handheld PD cameras such as the DayCor® UVollé offer an effective visual complement to online monitoring — allowing inspection teams to pinpoint UV corona on bushings during live patrol.
