What is a substation

What is a substation?

Electrical substations play a key part in effectively transmitting electricity through our national system. Find out what they do, how they work and where they fit into our electricity grid.

There’s more to our electricity system than where power is generated, or the cables that brings it to our homes and businesses. In fact, the national electricity grid comprises an ingenious network of specialist equipment that allows for the safe and effective transmission and distribution of electricity.

Substations are integral features within that grid and enable electricity to be transmitted at different voltages, safely and effectively.

How does an electricity substation work?

One of the main roles of substations is to convert electricity into different voltages. This is needed so the electricity can be transmitted throughout the country and into our homes, businesses and buildings.

Substations contain the specialist equipment that allows the voltage of electricity to be transformed (or ‘switched’). The voltage is stepped up or down through pieces of equipment called transformers, which sit within a substation’s site.

Transformers are electrical devices that transfer electrical energy by means of a changing magnetic field. They consist of two or more coils of wire and the difference in how many times each coil wraps around its metallic core will affect the change in voltage. This allows for the voltage to be increased or decreased.
Where do substations fit into the electricity network?

Transmission substations
Transmission substations are found where electricity enters the power grid. Because the output from power generators – such as power stations or wind farms

 
What else do substations do?
Substations contain equipment that help keep our electricity transmission and distribution systems running as smoothly as possible, without repeated failure or downtime.

Specialist equipment within the substation site can help prevent local network failures or power cuts. This happens when there is an overload of current in the network, which can be caused by things like mechanical failure or adverse weather conditions.
Substation transformers will fulfil different purposes in voltage conversion, depending on where electricity is in its transmission journey.

The two most common types of substations are transmission substations and distribution substations.

Electricity is then commonly transmitted through the high-voltage, overhead power lines you see supported by electricity pylons and can travel vast distances.