The localized ionization of air surrounding a high-voltage conductor when the electric field exceeds the dielectric strength of the air but is not strong enough to cause a complete breakdown or flashover. It produces a faint violet glow, a distinct buzzing noise, and ozone gas. Power companies monitor it because it causes power loss, radio interference, and long-term degradation of insulation.
You can hear heavy corona discharge on the 500 kV lines when the humidity gets high.
Also heard as
- corona
Related terms
Corona
Faint glowing discharge around high-voltage conductors where the air is overstressed, causing noise and loss.
Flashover
Disruptive discharge over or around insulation that creates a short circuit through the air.
Partial discharge
Tiny discharge in a void, on a surface or at a sharp edge that never spans the whole insulation, an early sign of decay.