Electricity is supplied by power stations
Power stations are usually located far from the city centre. Electricity generated by a power station is transmitted through a transmission and distribution network to the electricity users. The electricity produced at the power station is stepped up from about 20kV to 132kV, 275kV or 400kV by transformers in the transmission and distribution network, and transmitted through overhead, submarine or underground cables to substations in different parts of the city. This process is called “power transmission”.
High voltage (above 1kV) electric transmission is a technology by which electricity is transferred in bulk over relatively long distances. Substations of different levels have step-down transformers in them to reduce the voltage of the electricity to 380V or 220V, the level suitable for general electrical appliances. Electricity is then transferred to user buildings by local low voltage cables. This process is called “electricity distribution”.
Reaching the End-users
Generally, the electrical installations of a building include the main switch, the distribution board, the circuit supplying power to communal facilities and the circuit supplying power to individual users, etc. The electrical installations of each electricity user are usually equipped with a meter to record the amount of electricity consumed. This is how electricity is delivered to each household through the transmission and distribution network and the electrical installations of the building.