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Chances of occurrence of corona are maximum during
Humid weather
Dry weather
Winter
Summer
Humid weather
Corona discharge is the ionization of air surrounding a high-voltage transmission line conductor ┬╖ During humid weather, the air contains more moisture and suspended particles, which reduces the dielectric strength of the air, making it easier for ionization to occur at lower voltage gradients.
Corona discharge is the ionization of air surrounding a high-voltage transmission line conductor ┬╖ During humid weather, the air contains more moisture and suspended particles, which reduces the dielectric strength of the air, making it easier for ionization to occur at lower voltage gradients.
VcтАЛ=g0тАЛтЛЕm0тАЛтЛЕrтЛЕln(rDтАЛ) тАФ Critical disruptive voltage
PcтАЛтИЭ╬┤1тАЛ(VтИТVcтАЛ)2 тАФ Corona loss power relation where humidity lowers ╬┤
The critical disruptive voltage (VcтАЛ) is the voltage at which the electric field intensity at the surface of the conductor exceeds the dielectric strength of the air ┬╖ The presence of moisture (humidity) reduces the breakdown strength of air (╬┤),and since the corona loss (PcтАЛ) is inversely proportional to the air density factor (╬┤),humid conditions lead to higher corona losses and increased occurrence.
Corona is more prevalent in humid weather due to lower dielectric strength of moist air.
Corona loss increases with the frequency of the supply voltage.
Roughness factor (m0тАЛ) significantly influences the corona inception voltage.
Corona results in power loss, radio interference, and ozone production.
Acts as a natural safety valve against steep fronted surges
Reduces the magnitude of incoming surges on transmission lines
Causes significant power loss
Generates ozone, which causes corrosion of conductors
Causes radio and television interference
Ozone production
Electrostatic precipitators
Xerography (photocopying)
The air density factor ╬┤=273+t3.92bтАЛ where b is barometric pressure and t is temperature.
Option B (Dry weather) is incorrect because dry air has a higher dielectric strength, which resists ionization.
A is correct тАФ Humid weather decreases the dielectric strength of air, facilitating corona discharge at lower voltages.
Always remember that corona losses increase significantly in rainy or foggy weather compared to fair weather conditions.