Electricity grid – how electricity gets to you


22 January 2015

The power stations that generate electricity are usually located near energy sources, such as coal mines, natural gas production plants, or hydro-electric plants. But the electricity needs to be delivered to where most of its end users are located, which tends to be in cities and major towns

Enter the grid

‘The grid’ is shorthand for the complex transmission and distribution network that carries electricity from the power stations to your home or business.

Australia’s eastern and southern states have one of the largest interconnected ‘grids’ or power systems in the world. It’s a combination of state and privately-owned infrastructure assets and spans about 4,500 kilometres.

This grid services Queensland, New South Wales, the Australian Capital Territory, Victoria, South Australia and Tasmania. The wholesale market for electricity supplied via this grid is managed through the National Electricity Market (NEM).

The transmission and distribution networks in Western Australia, the Northern Territory and Mount Isa in Queensland operate separately from the NEM and from each other.

Transmission networks move the electricity from the power stations to the distribution networks. The electricity is transmitted at high voltages so that large amounts can travel efficiently over long distances.

**The 209km transmission line between Victoria and Tasmania is one of the longest submarine power cables in the world.1

When the electricity reaches the distribution networks, it passes through substations, which use transformers to lower the voltage of the electricity ready to deliver for everyday use.

Distribution power lines carry electricity to its final destination, such as your home or business. Power lines are often visible along the sides of roads, and sometimes they’re underground.

The role of transmission
and distribution networks

1…Power station
Generates electricity

2…Substation transformer
Raises the voltage of the electricity for efficient transportation

3…Transmission networks
Transports electricity over long distances

4…Substation transformer
Lowers the voltage of the electricity ready to deliver for everyday use

5…Distribution lines
Transports electricity to it’s final destination

6…Home and businesses
Electricity is used to power everday life included appliances, lighting and heating

Electricity at your home or business

Every building that uses electricity has a meter for measuring consumption and a switchboard for dividing the electricity up into circuits for each area of the building.

A circuit is a closed path that an electric current flows through to perform a function, such as making a light work or powering a motor. Wires inside the walls carry the electricity from the circuit to outlets and switches throughout the building.

Circuit breakers or fuses protect circuits from overloading. Circuit breakers act like a switch that automatically turns off the circuit when too much electricity flows through it. Fuses do a similar job, but they contain wires that melt in order to break the circuit.

Compliments of Origin Energy

  1. Australian Energy Regulator (AER), State of the Energy Market 2009, AER


Henry Sapiecha

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