05/26/2026
Corona on substations is detected by looking and listening for the tiny discharges that happen when high voltage “leaks” into the air around hardware, long before full insulation failure.
What corona is
Corona discharge is a partial electrical discharge that occurs when the electric field around a conductor is strong enough to ionize the surrounding air, but not strong enough to create a full arc. It often shows up as a bluish or purple glow with hissing or crackling sound around sharp edges, connectors, or damaged insulation on high‑voltage equipment.
Why this matters
Persistent corona and partial discharge eat away at insulators, metal fittings, and connectors until they eventually flash over or fail, causing forced outages and equipment damage. By detecting corona early in substations, you can plan targeted repairs, extend asset life, and avoid unplanned trips and safety incidents.
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