We all take it for granted that when we flick a switch lights magically illuminate or when we press a button our TV comes to life. Electricity is there when we need it, whatever time of day or night, but it goes on quite a journey to reach us. From a power station where it begins its life, to its end destination of our homes and businesses, electricity can travel vast distances, passing along overhead lines and underground cables and through several substations to increase or decrease the voltage to whatever is required.
Electricity can be generated from a range of different sources, including nuclear power, coal, gas, water, wind and the sun. The source of its generation depends on the type of power station it begins its life in. Once it is produced, the electricity leaves the power station at 25,000 volts and flows through overhead lines to a large substation.
Located near power stations, the role of substations is to further increase the voltage of the electric current so that it can travel long distances without losing power. It does this through the use of transformers, which can either decrease or increase the voltage of an electric current.
From the large substation, a network of overhead lines, carried on metal pylons, criss- cross the country carrying the current to the next stop on its journey. They are high above the ground and are fixed with special insulators to ensure the current doesn’t travel down the pylon to the ground. You will frequently see warning signs on these pylons as the voltage of the current can be up to 400,000 volts. When you consider that the voltage of a small battery is 1.5 volts, you can understand just how high that is! For extra safety, power lines are often buried underground near to and in towns and cities.
Rural small substations
Smaller substations located in rural areas serve to decrease the current to 33,000 volts for use by factories and to power trains.
Urban small substations
As the lines get closer to urban areas - our towns and cities - the voltage is decreased to between 11,000 and 33,000 volts for medium-scale factories.
Pole mounted transformers
Homes, offices, hospitals, small factories and traffic and street lights need a far smaller voltage so transformers mounted on wooden poles decrease the voltage to between 230 and 450 volts.