Question

Electrical energy is transmitted over large distance at high alternating voltages Which of the following statements is (are) correct?

• A. For a given power level there is a lower current
• B. Lower current implies less power loss
• C. Transmission lines can be made thinner
• D. It is easy to reduce the voltage at the receiving end using step-down transformers

Answer 1

Answer: (A), (B), (D)

Lower current implies less power loss
For a given power level there is a lower current
It is easy to reduce the voltage at the receiving end using step-down transformers

Power = Voltage x Current
As voltages are high so currents are lower. This is done to reduce the resistive losses.
Resistance Loss = $I_{rms}^{2}R$
So, lower current implies less power loss.
As resistance is inversely proportional to their diameter; hence decreasing their diameter by x will increase resistance by $x^2$ and hence increasing power loss hence not done.
As the voltage required for domestic and commercial uses are pretty less then they can be easily brought down by step-down transformers.