ABSTRACT
Electrical power is distributed nationally as AC. At the generator the voltage is typically 20 kV. The National Grid, however, operates at 132 and 270 kV in the UK and at similar values in other countries. This is to reduce power losses (I 2 R) in the cables; it keeps cable diameters to reasonable dimensions. The voltage is stepped up from the generator to the Grid by a transformer. At the user end of the Grid, a second transformer steps the voltage down again, usually via intermediate 33 and 11 kV stages.
