Transmission and distribution

In Western Australia, the electricity power grid is called the South West Interconnected System (SWIS).

The SWIS is made up of power stations, substations, transmission lines and distribution lines – this is called the infrastructure.

Flick a switch and your lights turn on, but for those who have wondered how electricity gets to you, here’s a step-by-step guide that traces the generation, transmission and distribution of electricity to your home.

Electricity is generated in power stations.

This electrical current is then transported from power stations to customers through a network of powerlines and cables. This network is made up of a transmission network and a distribution network.

The transmission network transports bulk power across long distances at high voltages. As it leaves the power station, electricity is passed through a transformer in the switchyard which converts it to a very high voltage (up to 330,000 volts!). This gives the electricity enough force to travel along the transmission lines to 'terminal' and 'zone' substations near where we live. These substations then convert the electricity to a lower voltage (33,000 volts or less), to make it ready for distribution to our homes

The distribution network delivers electricity from substations to our houses, over shorter distances and at lower voltages. The electricity comes into your house at the ‘point of supply’, which is either attached to the building (if you have overhead power), or a pillar just inside the boundary (underground power).

As you can see, it takes a lot of work to turn primary energy into the electricity that comes through when you flick on that switch!