Electricity Transmission And Distribution

The cables slung between pylons across open country are thinner than most people expect, and they are carrying the output of an entire power station. They manage it because the potential difference across them is enormous and the current in them is small, and that trade is the single decision on which the whole national supply rests. Get it wrong and a useful fraction of everything a station produces would be wasted warming up the countryside before it reached a single house.

This lesson follows the energy along that route, from the station to the socket, and asks you to be able to name every part of it in order. You will meet the two kinds of transformer that sit at the ends of the transmission line, one raising the voltage for the journey and one lowering it again so that what arrives in a street is safe to bring indoors. Then you will do the arithmetic that shows exactly how much is saved by sending the energy at hundreds of thousands of volts, using two equations you already have on the sheet at the back of your paper.