1.1 Power System Functions
The traditional power system is arranged as a hierarchy. Generators feed into a high voltage transmission system that facilitates bulk transfers of power over large distances. Connected to the transmission system are medium voltage distribution networks that take power from grid supply points and deliver it to the customers who are supplied a low voltage.
For a lot of its history, the electricity supply industry has operated as set of vertically integrated monopolies within certain geographic areas. Many countries, notably but not only, the UK, have sought to bring competition to this industry in order to provide better value to consumers. The approach in the UK, has been to unbundled the various functions within the industry and then use a combination of market mechanisms and regulation are then used to enhance economic efficiency. There are four functions on the supply-side: Generation; Transmission; Distribution and Supply And one function on the demand-side: Consumption The various functions are summaries in the table overleaf.
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Steam, gas, water or wind turbines driving alternators 275kV & 400kV overhead lines –“the national grid”
nPower, E.On, British Energy, SELCHP, Barking Power National Grid (owner and operator), Scottish Power (owner) UK Power Networks, Scottish and Southern EDF Energy, E.On, British Gas
132kV, 33kV, 11kV overhead lines and cables Purchase of energy on wholesale market, resell and bill Motors, heaters, lighting & supplies for electronic equipment
Industrial, commercial and domestic consumers
In the UK, the unbundling of the supply-side is known as “ownership unbundling” in which a company can only operate in one of the functions. Some of the large energy companies have split their business into