Question

Why electrical energy is transmitted at high voltage and low current?

Answer 1

1. The electrical energy is transmitted over long distances at a higher voltage to increase efficiency and minimize the loss of energy.
2. Low current reduces lower resistance losses.
3. We know that the power loss is given as $P=VI$ where $V$ is the voltage and $I$ is the current in the wire.
4. We also know that ohm's law is given as $V=IR$ where $R$ is the resistance.
5. By using the above two equations we get the power loss as $P=I^{2}R$.
6. Here, the resistance $R$ is almost constant for the wire.
7. So, the lower the current, the lower will be the power loss.
8. Now coming to the equation $P=VI$.
9. Here, we reduced the current, but we need to maintain the constant power because the power loss is mostly due to heat which cannot be a variable.
10. So to make the power constant the voltage needs to be increased as the current is reduced.

Hence, the electrical energy is transmitted for long distances at higher voltage and lower current.