Transmission towers

Around the Latrobe Valley and all the way to Melbourne are a series of large pylons and transmission lines. The transmission lines carry electricity to every part of Victoria. When it gets to cities where people live it is then sent out in different cables to our homes so that we can use it to cook our food, heat our homes, watch TV, play video games and do all those things that we need electricity for.

These transmission lines also connect together the electricity supply of South Australia, Victoria, New South Wales, The Australian Capital Territory, Queensland and Tasmania. This allows these states to share their electricity with each other so that if one state has too much electricity, a state that does not have enough does not have to waste money building a new power station but can buy the electricity it needs from the other state. This electricity connection of the states is called the National Grid

The transmission line which connects Victoria and Tasmania is called “Basslink” and is a cable buried beneath the sea of Bass Strait.

Western Australia is not part of this grid because it is too far away and it would cost too much to build the transmission line.

To send the electricity along these transmission lines we need a lot of electrical pressure. This is called voltage. After the electricity is generated it is sent to a transformer, which changes the voltage to five hundred thousand volts. It is then sent along the lines at this voltage to the cities. By doing this we do not lose much electricity on the way. In the cities other transformers change it to two hundred and forty volts, which we can use in our homes.

The cables, or conductors, used in the transmission lines used to be made of copper. Copper is heavy and also expensive so now these cables are made of aluminium. Electricity flows easily in aluminium. Another way of saying this is to say Aluminium is a good conductor of electricity.

Because these cables are not buried in the ground we do not have to worry about putting insulation around them to stop the electricity flowing into other things such as water in the ground or the ground itself. But because we are hanging them from the pylons we have to have a way of attaching them to the pylon so that the electricity does not flow into the pylon and down to the ground. If this happened we would have no electricity in our homes. We use large things called insulators made out of porcelain which is the same material your bathroom basin is made of. An insulator is something that electricity cannot pass through.