Electricity: The National Grid

Electricity: The National Grid

Understanding the National Grid

  • The National Grid is a system of cables and transformers used for the transmission of electrical power across the country.
  • It acts as a network that distributes generated electricity from power stations to homes, offices, and factories.

Step-Up and Step-Down Transformers

  • A step-up transformer is used at a power station to increase the voltage generated. This is because a high voltage ensures that power is transmitted efficiently and over long distances.
  • Step-down transformers are then used at local substations to reduce the voltage to a safe level for homes.

Power Stations and the Grid

  • Power stations usually produce electricity at 25,000 volts.
  • The generated electricity is then stepped up to 400,000 volts for transmission via the National Grid.

Pylons and Cables

  • Electricity is transmitted across the country via overhead cables on pylons.
  • These pylons are part of the National Grid, carrying a high voltage of up to 400,000 volts.
  • Underground cables are used in highly populated areas for safety and aesthetic reasons.

Substations and Households

  • Substations are part of the grid where the voltage of the electricity is stepped down from high transmission voltages to voltages safe for use in homes.
  • Electricity in the UK is delivered to households at a voltage of about 230 volts.

Efficiency of the National Grid

  • The National Grid is highly efficient in transmitting electricity between power stations and consumers.
  • The high voltage used in transmission reduces power loss due to heating effect.
  • Even so, some energy in the grid is lost as heat, due to the resistance of the cables and transformers.

Impact on the Environment

  • The National Grid utilises overhead power lines that can have an impact on the surroundings.
  • Mitigation measures include using underground cables, carefully planning the routes, and designing pylons to blend in with the landscape.