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The current drawn by the line due to corona losses is
Non-sinusoidal
Triangular
Square
Sinusoidal
Non-sinusoidal
Corona discharge in high-voltage transmission lines occurs when the electrical stress exceeds the dielectric strength of air, causing ionization. Because this process is highly non-linear and occurs only during the peaks of the voltage waveform, the resulting charging current is non-sinusoidal.
Corona discharge in high-voltage transmission lines occurs when the electrical stress exceeds the dielectric strength of air, causing ionization. Because this process is highly non-linear and occurs only during the peaks of the voltage waveform, the resulting charging current is non-sinusoidal.
VcтАЛ=goтАЛтЛЕ╬┤тЛЕrтЛЕln(rdтАЛ) тАФ Critical disruptive voltage formula
IcoronaтАЛтИЭтИСn=3,5,7...тАЛInтАЛsin(n╧Йt) тАФ Representing harmonic content
As the applied voltage across the line conductors reaches the critical disruptive voltage, the air surrounding the conductor ionizes. This ionization is not uniform throughout the cycle; it is intensive only when the instantaneous voltage exceeds the breakdown threshold of the air. This rapid, non-linear variation in capacitance and conductivity causes the line current to contain higher-order harmonics, resulting in a non-sinusoidal waveform.
Corona loss is non-linear due to the ionization process of air.
The charging current waveform becomes distorted, introducing harmonics.
Corona occurs primarily on conductors with small radii or during adverse weather conditions.
The presence of harmonics leads to radio interference and increased power loss.
Reduces the effective diameter of the conductor for voltage grading (marginal)
Provides a visible and audible warning of high voltage stress
Significant power loss (Corona loss)
Radio and television interference
Ozone production causing chemical corrosion of components
High-voltage AC transmission line design
Insulation coordination in EHV lines
Corona is more prominent during rain, fog, or snow due to decreased disruptive strength of air.
Option D is wrong because a pure sinusoidal current only occurs in linear, passive circuits without non-linear gaseous ionization processes.
A is correct тАФ The ionization process during corona discharge is highly non-linear, which causes the charging current to contain harmonic components, rendering it non-sinusoidal.
Always remember that any process involving gas ionization (like corona or arc discharge) is fundamentally non-linear, which universally introduces odd harmonics into the system current.