Key learning points

1. Power is transferred by electricity from power stations to consumers using the National Grid.
2. Step-up transformers increase the transmission voltage from a power station to the transmission line.
3. Step-down transformers decrease the transmission voltage from a transmission line to the consumer.
4. Transmission lines dissipate some energy by heating (P = I²R).
5. A very high transmission voltage reduces transmission current and the heating of transmission lines.

Keywords

• National Grid - a high voltage transmission system for getting electricity to where it is needed

• Transmission line - a high voltage cable often seen between electricity pylons

• Step-up transformer - a device that can change lower alternating voltages to higher ones

• Step-down transformer - a device that can change higher alternating voltages to lower ones

• Dissipation - the transfer of energy into the surroundings by heating

Common misconception