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Corona loss in a transmission line is dependent on
Diameter of the conductor
Material of the conductor
Height of the conductor
All of above
Diameter of the conductor
Corona loss is primarily dependent on the conductor diameter, as it directly influences the surface electric field intensity and the disruptive critical voltage of the transmission line. A larger conductor diameter reduces the surface potential gradient, thereby minimizing ionization of the surrounding air and reducing corona loss.
Corona loss is primarily dependent on the conductor diameter, as it directly influences the surface electric field intensity and the disruptive critical voltage of the transmission line. A larger conductor diameter reduces the surface potential gradient, thereby minimizing ionization of the surrounding air and reducing corona loss.
E=rln(rDтАЛ)VтАЛ тАФ Electric field intensity at conductor surface
PтИЭ(f+25)drтАЛтАЛ(VтИТVcтАЛ)2 тАФ Peek's law for power loss due to corona
Corona is an electrical discharge caused by the ionization of fluid surrounding a conductor, which occurs when the potential gradient exceeds the dielectric strength of air. Peek's law indicates that the loss is proportional to (f+25)drтАЛтАЛ(VтИТVcтАЛ)2, where r is the radius of the conductor. As the diameter increases, the surface electric field intensity E=rln(D/r)VтАЛ decreases, delaying the onset of ionization.
Corona loss is directly proportional to the supply frequency (f).
It depends on the surface condition of the conductor (roughness factor).
Air density and humidity significantly affect the disruptive critical voltage (VcтАЛ).
Larger diameter conductors (e.g., bundled conductors) are used to mitigate corona.
Used for visual signaling of high voltage lines.
Reduces the intensity of traveling waves by dissipating energy.
Leads to significant power loss in EHV lines.
Causes radio and television interference due to harmonic emissions.
Produces ozone, which can corrode metallic conductors.
Transmission line design (use of bundle conductors).
Corona motors and electro-static precipitators.
Option B (Material) has a negligible effect on corona loss compared to geometry.
Option C (Height) affects the capacitance and VcтАЛ slightly, but the diameter is the dominant design parameter for controlling the surface gradient.
The standard value for the disruptive critical voltage gradient is approximately 30 kV/cm (peak).
A is correct тАФ The conductor diameter inversely affects the surface potential gradient, directly influencing the onset and magnitude of corona discharge.
In exams, if asked for the most effective way to reduce corona, always prioritize 'Increasing Conductor Diameter' or 'Using Bundled Conductors' over changing material or height.