Title: Reading and Audio-Visual Assignments
Course: WGF 107 DEVELOPMENT > Section: Content

Title | Reading and Audio-Visual Assignments
Image | Simplified diagram of AC electricity distribution from generation stations to consumers. Transmission system elements are shown in blue, distribution system elements are in green.

Sub-Title | Improved Facility Electrical Service Benefits
Content | North American and European Power Distribution Systems North American and European power distribution systems differ in that North American systems tend to have a greater number of low-voltage step-down transformers located close to customers' premises. For example, in the US a pole-mounted transformer in a suburban setting may supply 7-11 houses,^[citation needed] whereas in the UK a typical urban or suburban low-voltage substation would normally be rated between 315 kVA and 1 MVA and supply a whole neighborhood. This is because the higher domestic voltage used in Europe (415 V vs 230 V) may be carried over a greater distance with acceptable power loss. An advantage of the North American system is that failure or maintenance on a single transformer will only affect a few customers. Advantages of the UK system are that the transformers are fewer in number, larger and more efficient, and due to the diversity of many loads there need be less spare capacity in the transformers, reducing waste. In North American city areas with many customers per unit area, network distribution may be used, with multiple transformers interconnected with low voltage distribution buses over several city blocks. Rural electrification systems, in contrast to urban systems, tend to use higher distribution voltages because of the longer distances covered by distribution lines (see Rural Electrification Administration). 7.2, 12.47, 25, and 34.5 kV distribution is common in the United States; 11 kV and 33 kV are common in the UK, Australia and New Zealand; 11 kV and 22 kV are common in South Africa. Other voltages are occasionally used.
Image | General layout of electricity networks. Voltages and depictions of electrical lines are typical for Germany and other European systems.
Content
Electrical Grid

An electrical grid (also referred to as an electricity grid or electric grid) is an interconnected network for delivering electricity from suppliers to consumers. It consists of generating stations that produce electrical power, high-voltage transmission lines that carry power from distant sources to demand centers, and distribution lines that connect individual customers.^[1]

Power stations may be located near a fuel source, at a dam site, or to take advantage of renewable energy sources, and are often located away from heavily populated areas. They are usually quite large to take advantage of the economies of scale. The electric power which is generated is stepped up to a higher voltage-at which it connects to the transmission network.

The transmission network will move the power long distances, sometimes across international boundaries, until it reaches its wholesale customer (usually the company that owns the local distribution network).

On arrival at a substation, the power will be stepped down from a transmission level voltage to a distribution level voltage. As it exits the substation, it enters the distribution wiring. Finally, upon arrival at the service location, the power is stepped down again from the distribution voltage to the required service voltage(s).
Links/Uploads | Electricity – Wikipedia           http://en.wikipedia.org/wiki/Electricity Rural Electric Administration (Rural Utilities Administration) – Wikipedia http://en.wikipedia.org/wiki/Rural_Electric_Administration Electrical Grid – Wikipedia http://en.wikipedia.org/wiki/Electrical_grid
Attributions | Images and content courtesy of Wikipedia – The Free Internet Encyclopedia.