Electricity distribution, a stage in delivery before retail of electricity includes medium-voltage or lesser than 50 kV power lines, electrical substations, and pole-mounted transformers, low-voltage or lesser than 1000 V distribution wiring, and many times even electricity meters.
Earlier direct current DC generators were connected to loads at the same voltage, and generation, transmission, and loads were of the same voltage due to voltage levels and motor-generator sets. Low voltages were used as a practical voltage for primary electrical load and required less insulation for distribution. Early DC generating plants were needed to be within approximately 1.5 miles of the customer to avoid large expensive conductors.
The introduction of alternating current or AC made possible the economical distribution of electric power over long distances. This allowed efficient rural and urban distribution with the voltage control. Though power electronics allows for conversion between direct current voltage levels, AC distribution continues due the economy, the efficiency, and the reliability of transformers.
Distribution networks vary. A radial network begins at the power station, and passes through the network area with no normal connection to any other supply. This kind of network has uses in rural areas. An interconnected network on the other hand services urban areas with multiple connections to other points of supply.