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The only advantage of corona is that it
Producers a pleasing luminous glow
Makes line current sinusoidal
Works as safety value for surface
Ozone gas is produced
Works as safety value for surface
Corona discharge acts as a 'safety valve' for electrical surges by dissipating the energy of transient voltage spikes (such as those from lightning or switching operations) through ionization of the surrounding air ┬╖ By allowing this discharge, it prevents the overvoltage from reaching a magnitude that could potentially cause insulation failure at the equipment terminals.
Corona discharge acts as a 'safety valve' for electrical surges by dissipating the energy of transient voltage spikes (such as those from lightning or switching operations) through ionization of the surrounding air ┬╖ By allowing this discharge, it prevents the overvoltage from reaching a magnitude that could potentially cause insulation failure at the equipment terminals.
EcтАЛ=E0тАЛ╬┤(1+╬┤rтАЛ0.3тАЛ) тАФ Peek's law for critical disruptive voltage gradient
P=244.2├Ч(f+25)drтАЛтАЛ(VтИТVcтАЛ)2├Ч10тИТ5 тАФ Power loss due to corona
When the electric field intensity at the surface of a conductor exceeds the dielectric strength of air (approx. 30 kV/cm), the air undergoes ionization ┬╖ This localized breakdown causes a leakage current that absorbs energy from the system ┬╖ Consequently, the crest of high-frequency surge transients is 'clipped' or reduced, protecting transformer and insulator insulation.
Corona occurs when the surface voltage gradient exceeds the disruptive strength of air.
It is accompanied by a hissing sound, ozone production, and power loss.
The 'safety valve' effect is minor compared to the total losses and interference caused by corona.
It helps in reducing the steepness of surge wavefronts.
Reduces the magnitude of transient overvoltages on transmission lines
Acts as an inherent protection mechanism for high-voltage insulation
Causes significant power loss
Produces ozone gas which corrodes metallic components
Generates radio and television interference
Reduces efficiency of power transmission
High voltage DC and AC transmission lines
Corona discharge air purification systems
Ozone generation for industrial use
Ozone production (Option D) is a consequence of corona, not an advantage.
The glow (Option A) is merely a visual indicator of ionization.
The safety valve effect (Option C) is considered the only functional advantage in power system protection.
C is correct тАФ Corona acts as a safety valve by dissipating energy from transient high-voltage surges, thereby protecting the insulation of the transmission line components.
Always remember that while corona is generally undesirable due to power loss and interference, its role in suppressing surge voltage transients makes it a passive, unintentional protective element in high-voltage power systems.