The national grid

• National Grid


  A system of transformers and high-voltage cables that connects power stations to homes
• Electricity has to get from the power stations to around 25 million homes in the UK
• Energy is always lost in the power cables due to the resistance of the wires
• The greater the distance between the power station and the homes, the greater the energy loss
• Electricity distribution by the National Grid

  1. Passes through step-up transformers to increase the potential difference

  2. Passes through high-voltage cables

  3. Passes through step-down transformers to reduce the potential difference

  4. Passes into homes
• Step-up transformers


  Increase the potential difference to several hundred thousand volts to reduce energy loss in transmission cables
• Step-down transformers


  Reduce the potential difference to around 230 volts before the electricity passes to homes
• Less energy is lost in the power cables when the potential difference is very high
• The potential difference from the high-voltage cables cannot be passed on to homes directly as it would be far too high
• The National Grid connects the power stations to the homes, but only the transformers and cables are actually called the National Grid