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The corona loss on a particular system at 50Hz is 1 kWтИХ phase тИХ km. The corona loss on the same system with supply frequency 25 Hz will be
1 kW/phase/km
0.5 kW/phase/km
0.667 kW/phase/km
None of the above
0.667 kW/phase/km
Corona loss in a transmission line is calculated using Peek's formula, where loss is directly proportional to (f+25), where f is the supply frequency. By calculating the ratio of losses at 50 Hz and 25 Hz, the new loss is found to be 0.667 kW/phase/km.
Corona loss in a transmission line is calculated using Peek's formula, where loss is directly proportional to (f+25), where f is the supply frequency. By calculating the ratio of losses at 50 Hz and 25 Hz, the new loss is found to be 0.667 kW/phase/km.
PтИЭ(f+25) тАФ Relationship between corona loss and frequency
P2тАЛP1тАЛтАЛ=f2тАЛ+25f1тАЛ+25тАЛ тАФ Ratio calculation formula
Corona occurs when the electric field intensity at the conductor surface exceeds the dielectric strength of air. Peek's empirical formula for corona power loss is P=244тЛЕ╬┤f+25тАЛDrтАЛтАЛ(VтИТVcтАЛ)2├Ч10тИТ5 kW/phase/km. Since all parameters except frequency (f) remain constant, the power loss P is proportional to (f+25).
Corona loss is dependent on the frequency of the supply voltage.
The factor (f + 25) is derived from Peek's formula.
Lower frequency leads to lower corona loss for the same voltage levels.
Reduces power dissipation in long-distance lines.
Minimizes interference with communication lines.
Occurs primarily at high voltages (Extra High Voltage lines).
Causes ozone formation and chemical corrosion.
High Voltage Transmission (EHV/UHV).
Design of bundled conductors.
Peek's formula is valid for fair weather conditions.
Option B (0.5 kW) is incorrect because the loss is not directly proportional to frequency alone, but to the term (f+25).
C is correct тАФ Applying the ratio P2тАЛP1тАЛтАЛ=f2тАЛ+25f1тАЛ+25тАЛ with f1тАЛ=50 Hz and f2тАЛ=25 Hz yields P2тАЛ=1├Ч7550тАЛ=0.667 kW/phase/km.
Always verify if a parameter (like frequency) is in the numerator or part of a binomial expression in transmission formulas before assuming direct proportionality.