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The effect of corona is
Increased loss
Increased reactance
Increased inductance
All of above
Increased loss
Corona is an electrical discharge caused by the ionization of air surrounding a conductor when the potential gradient exceeds the dielectric strength of air ┬╖ This process dissipates electrical energy in the form of light, heat, sound, and radio interference, directly leading to power loss.
Corona is an electrical discharge caused by the ionization of air surrounding a conductor when the potential gradient exceeds the dielectric strength of air ┬╖ This process dissipates electrical energy in the form of light, heat, sound, and radio interference, directly leading to power loss.
PcтАЛ=242.2╬┤f+25тАЛDrтАЛтАЛ(VтИТVcтАЛ)2├Ч10тИТ5 тАФ Empirical formula by Peek for corona power loss in kW per phase per kilometer.
VcтАЛ=g0тАЛтЛЕm0тАЛтЛЕ╬┤тЛЕrтЛЕln(rDтАЛ) тАФ Disruptive critical voltage equation where g0тАЛ is the dielectric strength of air.
When the surface electric field intensity of a conductor exceeds the breakdown strength of air (approx. 30 kV/cm peak), air molecules become ionized ┬╖ These free electrons and ions accelerate toward the conductor, causing collisions that sustain the discharge ┬╖ This continuous ionization process draws current from the line, manifesting as energy dissipation known as corona loss.
Corona occurs when the surface voltage gradient exceeds the air breakdown strength.
It causes power loss, radio interference, ozone gas production, and audible noise.
Corona loss increases significantly with supply frequency and atmospheric moisture.
Increasing conductor diameter or spacing reduces the probability of corona.
Reduces the severity of steep-fronted surges on the line
Corona discharge provides a natural dissipative mechanism for overvoltages
Energy loss reduces transmission efficiency
Produces ozone, which can cause chemical corrosion of copper conductors
Causes significant radio and television interference
Corona discharge is used in electrostatic precipitators
Used in ozone generators for water purification
Factors increasing corona: rough conductor surface, dirt/dust, bad weather (rain/fog).
Option B (Reactance) and C (Inductance) are unaffected by corona, as they depend purely on the physical geometry and arrangement of conductors (GMD and GMR).
A is correct тАФ Corona discharge leads to the conversion of electrical energy into thermal, acoustic, and electromagnetic energy, resulting in power dissipation.
Always remember that corona affects only the resistance (or effective power loss) of the line; it does not change the self-inductance or capacitance, which are determined solely by geometric parameters (D and r).