Electricity Stages in Electricity Distribution

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  • Topic: Electricity distribution, Transformer, Electric power transmission
  • Pages : 6 (2200 words )
  • Download(s) : 442
  • Published : February 27, 2011
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Electricity stages in Electricity distribution is the final stage in the delivery (before retail) of electricity to end users. A distribution system's network carries electricity from the transmission system and delivers it to consumers. Typically, the network would include medium-voltage (less than 50 kV) power lines, electrical substations and pole-mounted transformers, low-voltage (less than 1 kV) distribution wiring and sometimes electricity meters. Contents[hide] * 1 Modern distribution systems * 2 History * 2.1 Introduction of alternating current * 3 Distribution network configurations * 4 Distribution industry * 5 See also * 6 References * 7 External links * 8 Further reading| [edit] Modern distribution systems

Electric distribution substations transform power from transmission voltage to the lower voltage used for local distribution to homes and businesses See also: List of countries with mains power plugs, voltages and frequencies The modern distribution system begins as the primary circuit leaves the sub-station and ends as the secondary service enters the customer's meter socket. A variety of methods, materials, and equipment are used among the various utility companies, but the end result is similar. First, the energy leaves the sub-station in a primary circuit, usually with all three phases. The actual attachment to a building varies in different parts of the world. Most areas provide three phase industrial service. There is no substitute for three-phase service to run motors and heavy industrial equipment. A ground is normally provided, connected to conductive cases and other safety equipment, to keep current away from equipment and people. Distribution voltages vary depending on customer need, equipment and availability. Delivered voltage is usually constructed using stock transformers, and either the voltage difference between phase and neutral or the voltage difference from phase to phase. In many areas, "delta" three phase service is common. Delta service has no distributed neutral wire and is therefore less expensive. The three coils in the generator rotor are in series, in a loop, with the connections made at the three joints between the coils. Ground is provided as a low resistance earth ground, sometimes attached to a synthetic ground made by a transformer in a substation. High frequency noise (like that made by arc furnaces) can sometimes cause transients on a synthetic ground. In North America and Latin America, three phase service is often a Y (wye) in which the neutral is directly connected to the center of the generator rotor. Wye service resists transients better than delta, since the distributed neutral provides a low-resistance metallic return to the generator. Wye service is recognizable when a grid has four wires, once of which is lightly insulated. Many areas in the world use single phase 220 V or 230 V residential and light industrial service. In this system, a high voltage distribution network supplies a few substations per city, and the 230V power from each substation is directly distributed. A hot wire and neutral are connected to the building from one phase of three phase service. In the U.S. and parts of Canada and Latin America, split phase service is the most common. Split phase provides both 120 V and 240 V service with only three wires. Split phase has substations that provide intermediate voltage. The house voltages are provided by neighborhood transformers that lower the voltage of a phase of the distributed three-phase. The neutral is directly connected to the three-phase neutral. Socket voltages are only 120 V, but 240 V is available for heavy appliances because the two phases oppose each other. Japan has a large number of small industrial manufacturers, and therefore supplies standard low voltage three phase service in many suburbs. Also, Japan normally supplies residential service as two phases of a three phase service, with a neutral. Rural...
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