An electrical network is an interconnected network to deliver electricity from producers to consumers. It consists of the generation of stations that produce electrical energy, high voltage transmission lines that transport energy from distant sources to demand centers and distribution lines that connect individual customers.
Power stations can be located near a fuel source, at the site of a dam, or to take advantage of renewable energy sources, and are often located away from densely populated areas. The electrical power that is generated is intensified to a higher voltage to which it is connected to the electric power transmission network.
The bulk power transmission network will move energy over long distances, sometimes across international borders, until it reaches your wholesale customer.
Upon reaching a substation, the power will decrease from a transmission level voltage to a distribution level voltage. When you leave the substation, enter the distribution wiring. Finally, upon reaching the service location, the energy goes back down from the distribution voltage to the required service voltage.
Electric networks vary in size, from covering a single building through national networks that cover whole countries, to transnational networks that can cross continents.
Although electricity grids are widespread, 1.4 billion people are not connected to an electricity grid.
The grids are designed to supply voltages at largely constant amplitudes. This must be achieved with a variable demand, variable reactive loads and even non-linear loads, with electricity provided by generators and distribution and transmission equipment that are not perfectly reliable. Often, networks use tap changers in transformers near consumers to adjust the voltage and keep it within specifications.
The transmission networks are complex with redundant routes. For example, see the map of the United States high-voltage transmission network.
Network diagram of a high voltage transmission system, showing the interconnection between the different voltage levels. This diagram represents the electrical structure of the network, rather than its physical geography.
The structure, or “topology” of a grid can vary according to budget constraints, system reliability requirements, and load and generation characteristics. The physical design is often forced by the available land and its geology. Distribution networks are divided into two types, radial or network.
The simplest topology for a distribution or transmission network is a radial structure. This is a tree form where the energy from a large source radiates towards progressively lower voltage lines until it reaches the destination houses and businesses. However, individual faults can eliminate entire branches of the tree.