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The power transmitted will be maximum when
Corona losses are minimum
Receiving end voltage is high
Reactance is high
Sending end voltage is high
Corona losses are minimum
Maximum power transfer in a transmission line is inherently constrained by the stability limit and dielectric stress. Operating at a condition where corona loss is minimized (typically via optimized conductor geometry and voltage regulation) ensures that the line remains within its safe thermal and electrical limits, allowing for maximum efficient power throughput without triggering discharge instabilities.
Maximum power transfer in a transmission line is inherently constrained by the stability limit and dielectric stress. Operating at a condition where corona loss is minimized (typically via optimized conductor geometry and voltage regulation) ensures that the line remains within its safe thermal and electrical limits, allowing for maximum efficient power throughput without triggering discharge instabilities.
P=XVsтАЛVrтАЛтАЛsin╬┤ тАФ Power transfer equation for a short transmission line
PcoronaтАЛтИЭ(f+25)drтАЛтАЛ(VтИТVcтАЛ)2 тАФ Empirical relation for corona power loss
The maximum power transfer capability of a transmission line is given by P=XVsтАЛVrтАЛтАЛsin╬┤. While increasing VsтАЛ or VrтАЛ theoretically increases P, these voltages are restricted by corona inception voltage VcтАЛ. If corona occurs, the resulting power loss and line degradation force a de-rating of the line's capacity. Therefore, maximizing efficiency and minimizing corona losses allows the system to operate at the peak of its stable power-transfer curve.
Corona loss is an undesirable power dissipation occurring when the surface electric field exceeds the dielectric strength of air.
The surge impedance loading (SIL) is often the baseline for stable power transmission.
Operating below the corona inception voltage maximizes the efficiency and effective transmission capacity.
Reduced electromagnetic interference (EMI) with communication lines.
Higher transmission efficiency due to lower I2R and corona-related power losses.
Large conductor bundles are expensive.
Increased weight on transmission towers due to larger conductor diameters.
Extra High Voltage (EHV) and Ultra High Voltage (UHV) transmission networks.
Long-distance power grids where stable power transfer is critical.
Option B and D are incorrect because merely increasing voltage leads to higher corona losses and potential dielectric breakdown, which limits power transfer.
Option C is incorrect because a high reactance (X) actually decreases the power transfer capacity as per P=XVsтАЛVrтАЛтАЛsin╬┤.
A is correct тАФ Minimizing corona losses ensures that the transmission line operates within safe dielectric limits, permitting the maximum stable power transfer capacity.
Always remember the trade-off between voltage level and corona discharge; higher voltages improve stability limits (PтИЭV2) but increase losses if conductor radius is not increased proportionally.