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Electric power transmission is the second process in the delivery of electricity to consumers. Electrical energy is generated by power plants and is then sold as a commodity to end consumers by retailers. The electric energy transmission and electricity distribution networks allow the delivery of the generated electricity to consumers. The rapid industrialization in the 20th century made electrical transmission lines and grids a critical part of the economic infrastructure in most industrialized nations. The article on electrical energy is located elsewhere. ...
Electrical energy or Electromagnetic energy is a form of energy present in any electric field or magnetic field, or in any volume containing electromagnetic radiation. ...
Itaipu Dam is a hydroelectric generating station Electricity generation is the first process in the delivery of electricity to consumers. ...
A power station (also power plant) is a facility for the generation of electric power. ...
In economics, consumers are individuals or households that consume goods and services generated within the economy. ...
Electricity retailing is the final process in the delivery of electricity from generation to the consumer. ...
Electricity distribution is the penultimate process in the delivery of electric power, the part between transmission and user purchase from an electricity retailer. ...
(19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901–2000 in the sense of the Gregorian calendar (1900–1999 in the...
The transmission grid allows large generation facilities such as hydroelectric dams, fossil fuel plants, nuclear power plants, etc. run by large public and private utility organizations to produce large quantities of energy and then deliver it to distribution networks for delivery to retail customers for consumption. Transmission towers marching through the countryside. ...
Transmission towers marching through the countryside. ...
A pylon is a tall steel lattice structure used to support overhead electricity conductors for power transmission. ...
Electric transmission lines, picture taken by myself. ...
Electric transmission lines, picture taken by myself. ...
Lund is a city in Scania in southernmost Sweden, and the center of the Lund Municipality. ...
Hydroelectricity, or hydroelectric power, is a form of hydropower, (i. ...
Coal rail cars in Ashtabula, Ohio Fossil fuels, also known as mineral fuels, are hydrocarbon-containing natural resources such as coal, petroleum and natural gas. ...
Nuclear power station at Leibstadt, Switzerland. ...
Electricity is usually sent over long distance through a combination of overhead power transmission lines (such as those in the photo on the right) and buried cables.
The first large scale hydroelectric generators in the USA (engineered and installed under the technical oversight of Nikola Tesla) were installed at Niagara Falls and provided electricity to Buffalo, New York via power transmission lines. Nikola Tesla (July 9/July 10, 1856 - January 7, 1943) was a physicist, inventor, and electrical engineer of unusual intellectual brilliance and practical achievement. ...
The Horseshoe Falls, one of the three Niagara Falls. ...
Buffalo, also known as the Queen city, and the City of Good Neighbors, is an American city in western New York. ...
AC power transmission
AC Power Transmission is the ransmission of electric power by alternating current. Usually transmission lines use three phase AC current. In countries with extensive electric railways, sometimes single phase AC current is used as traction current for railway traction. Transmission lines in Lund, Sweden Electric power, often known as power or electricity, involves the production and delivery of electrical energy in sufficient quantities to operate domestic appliances, office equipment, industrial machinery and provide sufficient energy for both domestic and commercial lighting, heating, cooking and industrial processes. ...
An alternating current (AC) is an electrical current, where the magnitude and direction of the current varies cyclically, as opposed to direct current, where the direction of the current stays constant. ...
Three-phase power transformer which is the sole transferpoint for electricity to a suburban shopping mall in Canada. ...
In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ...
The generation of AC electric power is commonly three phase, in which the waveforms of three supply conductors are offset from one another by 120 . ...
By traction current one understands the electric current, which is used for the drive of electrical trains. ...
Traction is applied mechanical force used to achieve motion. ...
Transmission-level voltages are usually considered to be 115 kV and above. Lower voltages such as 66 kV and 33 kV are usually considered sub-transmission voltages but are occasionally used on long lines with light loads. Voltages less than 33 kV are usually used for distribution. Voltages above 230 kV are considered extra high voltage and require different designs compared to equipment used at lower voltages. This page deals with mathematical distributions. ...
History The first transmission of three-phase alternating current using high voltage took place in the year 1891 on the occasion of the international electricity exhibition in Frankfurt. Between Lauffen at the Neckar and Frankfurt/Main one approx. 175 kilometre long powerline for a voltage of 15 to 25 kV was built in 1891.
Initially transmission lines were supported by porcelain pin-and-sleeve insulators similar to those used for telegraph and telephone lines. However, these reached a practical limit of 40 kV. In 1907 the invention of the strain-type insulators by H. W. Buck of the Niagara Falls Power Corporation and E. M. Hewlett of General Electric allowed practical insulators of any length to be constructed, which allowed the use of higher voltages. Telegraphy (from the Greek words tele = far away and grapho = write) is the long distance transmission of written messages without physical transport of letters, originally over wire. ...
A telephone handset A touch-tone telephone dial Telephone This article is about telephone technology. ...
In 1912 between Lauchhammer and Riesa the first three-phase alternating current with 110 kV took place. On April 17th, 1929 there was the inaugauration of the first 220 kV line in Germany running from Brauweiler near Cologne, over Kelsterbach near Frankfurt, Rheinau near Mannheim, Ludwigsburg/Hoheneck toward Austria. The masts of this line were already were constructed for eventual upgrade to 380 kV. However the first transmission with 380 kV took place in Germany on October 5th, 1957 between the substations in Rommerskirchen and Ludwigsburg/Hoheneck. In 1967 the first extra-high-voltage transmission with 735 kV took place on a Hydro-Québec transmission line. In 1982 the first transmission with 1200kV took place in the former Soviet Union. Hydro-Québec headquarters in downtown Montreal, with logo Hydro-Québec is a government-owned corporation that provides hydroelectric power for Quebec, Canada. ...
Bulk power transmission A transmission grid is made up of power stations, transmission circuits, and substations. Energy is usually transmitted on the grid with 3-phase alternating current (AC). The voltage level on the bulk power transmission system is typically between 115 kV and 765 kV. Energy may also be transmitted using high voltage direct current. A power station (also power plant) is a facility for the generation of electric power. ...
An aerial substation A substation is the part of an electricity transmission and distribution system where voltage is transformed from low to high and vice versa using transformers. ...
An alternating current (AC) is an electrical current, where the magnitude and direction of the current varies cyclically, as opposed to direct current, where the direction of the current stays constant. ...
HVDC or high-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power. ...
Grid input At the generating plants the energy is produced at a relatively low voltage of up to 25 kV (Grigsby, 2001, p. 4-4), then stepped up by the power station transformer to a higher voltage for transmission over long distances to grid exit points (substations). Generator redirects here. ...
Transformers - Typical electrical configurations. ...
In the physical sciences, potential difference is the difference in potential between two points in a conservative vector field. ...
An aerial substation A substation is the part of an electricity transmission and distribution system where voltage is transformed from low to high and vice versa using transformers. ...
Losses It is necessary to transmit the electricity at high voltage to reduce the percentage of energy lost. For a given amount of power transmitted, a higher voltage reduces the current and resistance losses in the conductor. Long distance transmission is typically at voltages of 100 kV and higher. Transmission voltages up to 765 kV AC and up to +/-533 kV DC are currently used in long-distance overhead transmission lines.
Transmission and distribution losses in the USA were estimated at 7.2% in 1995 [1] (http://climatetechnology.gov/library/2003/tech-options/tech-options-1-3-2.pdf), and in the UK at 7.4% in 1998. [2] (http://www.powerwatch.org.uk/energy/graham.asp) 1995 was a common year starting on Sunday of the Gregorian calendar. ...
1998 is a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ...
In an alternating current transmission line, the inductance and capacitance of the line conductors can be significant. The currents that flow in these components of transmission line impedance constitute reactive power, which transmits no energy to the load. Reactive current flow causes extra losses in the transmission circuit. The fraction of total energy flow (power) which is resistive (as opposed to reactive) power is the power factor. Utilities add capacitor banks and other components throughout the system (such as phase-shifting transformers, static VAR compensators, and flexible AC transmission systems) to control reactive power flow for reduction of losses and stabilization of system voltage. Inductance is a physical characteristic of an inductor, which is an electrical device that produces at any time a voltage proportional to the instantaneous rate of change in current flowing through it. ...
Capacitance is a measure of the amount of electric charge stored for a given electric potential. ...
In electrical engineering, impedance is a measure for the manner and degree a component resists the flow of electrical current if a given voltage is applied. ...
Reactive power is an abstract quantity, typically used by power engineers to describe a certain type of energy flow in an electric distribution system. ...
The power factor of an AC electric power system is defined as the ratio of the real power to the apparent power. ...
Transformers - Typical electrical configurations. ...
Transmission lines both generate and absorb reactive power. ...
FACTS (Flexible AC Transmission Systems) is a technology for electric power transmission defined by the IEEE as a power electronic based system and other static equipment that provide control of one or more ac transmission system parameters to enhance controllability and increase power transfer capability. ...
HVDC High voltage DC (HVDC) is used to transmit large amounts of power over long distances or for interconnections between asynchronous grids. When electrical energy is required to be transmitted over very long distances, it can be more economical to transmit using direct current instead of alternating current. For a long transmission line, the value of the smaller losses, and reduced construction cost of a DC line, can offset the additional cost of converter stations at each end of the line. Also, at high AC voltages significant amounts of energy are lost due to corona discharge, the capacitance between phases or, in the case of buried cables, between phases and the soil or water in which the cable is buried. Since the power flow through an HVDC link is directly controllable, HVDC links are sometimes used within a grid to stabilize the grid against control problems with the AC energy flow. HVDC or high-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power. ...
Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ...
An alternating current (AC) is an electrical current, where the magnitude and direction of the current varies cyclically, as opposed to direct current, where the direction of the current stays constant. ...
In electricity, a corona discharge is an electrical discharge brought on by the ionization of a fluid surrounding a conductor, which occurs when the potential gradient exceeds a certain value, in situations where sparking is not favoured. ...
Capacitance is a measure of the amount of electric charge stored for a given electric potential. ...
For the heavy metal band see Soil (band) Soil is the layer of minerals and organic matter, in thickness from centimetres to a metre or more, on the land surface. ...
Water (from the Old English word wæter) is a colourless, tasteless, and odourless substance that is essential to all known forms of life and is known also as the most universal solvent. ...
Grid exit At the substations, transformers are again used to step the voltage down to a lower voltage for distribution to commercial and residential users. This distribution is accomplished with a combination of sub-transmission (34.5 to 115 kV, varying by country and customer requirements) and distribution (4.6 to 25 kV). Finally, at the point of use, the energy is transformed to low voltage (100 to 600 V, varying by country and customer requirements). An aerial substation A substation is the part of an electricity transmission and distribution system where voltage is transformed from low to high and vice versa using transformers. ...
Electricity distribution is the penultimate process in the delivery of electric power, the part between transmission and user purchase from an electricity retailer. ...
Communications Operators of long transmission lines require reliable communications for control of the power grid and, often, associated generation and distribution facilities. Fault-sensing protection relays at each end of the line must communicate to monitor the flow of power into and out of the protected line section. Protection of the transmission line from short circuits and other faults is usually so critical that common carrier telecommunications is insufficiently reliable. In remote areas a common carrier may not be available at all. Communication systems associated with a transmission project may use: SCADA (Supervisory Control and Data Acquisition) systems are used in industrial and civil engineering applications to control distributed systems from a master location. ...
Automotive style miniature relay A relay is an electrical switch that opens and closes automatically under control of another electrical circuit. ...
For alternate meanings see Short circuit (disambiguation) A short circuit (sometimes known as simply a short) is a fault whereby electricity moves through a circuit in an unintended path, usually due to a connection forming where none was expected. ...
A common carrier is an organization that transports a product or service using its facilities, or those of other carriers. ...
Rarely, and for short distances, a utility will use pilot-wires strung along the transmission line path. Leased circuits from common carriers are not preferred since availability is not under control of the electric power transmission organization. This page is about the radiation; for the appliance, see microwave oven. ...
Power line communication (PLC), also called Broadband over Power Lines (BPL) or Power Line Telecoms (PLT), is a wireline method of communication that uses the existing electric power transmission and electricity distribution lines. ...
Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ...
Transmission lines can also be used to carry data: this is called power-line carrier, or PLC. PLC signals can be easily received with a radio for the longwave range. Power line communication (PLC), also called Broadband over Power Lines (BPL) or Power Line Telecoms (PLT), is a wireline method of communication that uses the existing electric power transmission and electricity distribution lines. ...
Sometimes there are also communications cables using the transmission line structures. These are generally fibre optic cables. They are often integrated in the ground (or earth) conductor. Sometimes a standalone cable is used, which is commonly fixed to the upper crossbar. On the EnBW system in Germany, the communication cable can be suspended from the ground (earth) conductor or strung as a standalone cable. Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ...
Some jurisdictions, such as Minnesota, prohibit energy transmission companies from selling surplus communication bandwidth or acting as a telecommunications common carrier. Where the regulatory structure permits, the utility can sell capacity in extra "dark fibres" to a common carrier, providng another revenue stream for the line. State nickname: North Star State Other U.S. States Capital Saint Paul Largest city Minneapolis Governor Tim Pawlenty Official languages None Area 225,365 km² (12th) - Land 206,375 km² - Water 18,990 km² (8. ...
A common carrier is an organization that transports a product or service using its facilities, or those of other carriers. ...
Electricity market reform Transmission is a natural monopoly and there are moves in many countries to separately regulate transmission (see New Zealand Electricity Market). In the USA the Federal Energy Regulatory Commission has issued a notice of proposed rulemaking setting out a proposed Standard Market Design that would see the establishment of Regional Transmission Organizations (RTOs). The first RTO in North America is the Midwest Independent Transmission System Operator (MISO) [3] (http://www.midwestmarket.org). MISO's authority covers parts of the transmission grid in the United States midwest and one province of Canada (through a coordination agreement with Manitoba Hydro). MISO also operates the wholesale power market in the United States portion of this area. In economics, a natural monopoly exists when production of a particular product can be done cheapest when there is only one firm doing the producing. ...
Up to 1994, the New Zealand Electricity Market had a system of monopoly providers of generation, transmission, distribution and retailing. ...
Federal Energy Regulatory Commission (FERC): The U.S. federal agency with jurisdiction over interstate electricity sales, wholesale electric rates, hydroelectric licensing, natural gas pricing, oil pipeline rates, and gas pipeline certification. ...
A notice of proposed rulemaking or NPRM is issued by law when a regulatory agency of the United States Federal Government wishes to add, remove, or change a rule (or regulation). ...
Founded in 1961, Manitoba Hydro is the electric power and natural gas utility in the province of Manitoba, Canada. ...
Spain was the first country to establish a Regional Transmission Organization. In that country transmission operations and market operations are controlled by separate companies. The transmission system operator is Red Eléctrica de España (REE) [4] (http://www.ree.es/ingles/i-index_quien.html) and the wholesale electricity market operator is Operador del Mercado Ibérico de Energía - Polo Español, S.A. (OMEL) [5] (http://www.omel.es). Spain's transmission system is interconnected with those of France, Portugal, and Morocco.
Health concerns It is argued by some that living near high voltage power lines presents a danger to animals and humans. Some have claimed that electromagnetic radiation from power lines elevates the risk of certain types of cancer. Some studies support this theory, and others do not. Most studies of large populations fail to show a clear correlation between cancer and the proximity of power lines, but a 2005 Oxford University study did find a statistically significant elevation of childhood leukaemia rates [6] (http://www.hpa.org.uk/hpa/news/articles/press_releases/2005/050603_childhood_cancer_voltage.htm). Recent studies (2003) connect DNA-breakage with low level AC magnetic fields. Electromagnetic radiation or EM radiation is a combination (cross product) of oscillating electric and magnetic fields perpendicular to each other, moving through space as a wave, effectively transporting energy and momentum. ...
2005 is a common year starting on Saturday of the Gregorian calendar and is the current year. ...
The University of Oxford, situated in the city of Oxford in England, is the oldest university in the English-speaking world. ...
Leukemia (leukaemia in Commonwealth English) is a group of blood diseases characterized by malignancies (cancer) of the blood-forming tissues. ...
The current mainstream scientific view is that power lines are unlikely to pose an increased risk of cancer or other somatic diseases. For a detailed discussion of this topic, including references to a variety of scientific studies, see the Power Lines and Cancer FAQ (http://www.mcw.edu/gcrc/cop/powerlines-cancer-FAQ/toc.html). The issue is also discussed at some length in Robert L. Park's book Voodoo Science. Robert L. Park is a professor of physics at the University of Maryland, College Park. ...
Voodoo Science, another term for pseudoscience, was popularized in a book of the same title (ISBN 0195147103) written in 2001 by Robert L. Park. ...
Alternate transmission methods There is a potential for the use of superconducting cable transmission in order to supply electricity to consumers, given that the waste is halved using this method. Such cables are particularly suited to high load density areas such as the business district of large cities, where purchase of a right of way for cables would be very costly. [7] (http://www.futureenergies.com/print.php?sid=237) Superconductivity is a phenomenon occurring in certain materials at low temperatures, characterised by the complete absence of electrical resistance and the damping of the interior magnetic field (the Meissner effect. ...
Special transmission grids for railways In some countries where electric trains run on low frequency AC (e.g. 16.7 Hz) power there are separate single phase traction power networks operated by the railways. These grids are fed by separate generators in some power stations or by traction current converter plants from the public three phase AC network. The transmission voltages are usually A traction power network is a electricity grid for the supply of electric trains. ...
A traction current converter plant is an electrical substation that converts electric power from that form used as public electricity mains current to an appropriate voltage, current type, and frequency to supply railways with traction current. ...
- 25 and 50 kV (South Africa)
- 66 kV (Switzerland),
- 110 kV (Germany, Austria)
- 132 kV (also Switzerland).
Records - Highest transmission voltage (AC): 1150 kV on Powerline Ekibastuz-Kokshetau
- Highest transmission voltage (DC): +/-600 kV on HVDC Itaipu
- Highest pylons: Pylons of Pearl River Crossing (height: 253 metres and 240 metres)
- Longest powerline: Inga-Shaba (length: 1700 kilometres)
- longest submarine cables: Basslink (under construction, length of submarine/underground cable: 290 kilometres, total length: 357.4 kilometres), Baltic-Cable (length of submarine/underground cable: 249 kilometres, total length: 261 kilometres)
The Powerline Ekibastuz-Kokshetau is the powerline designed for the highest transmission voltage (1150 kV) in the world. ...
The HVDC Itaipu is a HVDC transmission progject from the Itaipu hydroelectric power plant to the city of São Paulo,Brazil. ...
A pylon is a tall steel lattice structure used to support overhead electricity conductors for power transmission. ...
The pylons of the Pearl River Crossing are three electricity pylons with heights of 240 metres, 253 metres, and 80 metres. ...
Inga-Shaba is the name for a HVDC-scheme in Zaire, which went in service in 1979. ...
The Basslink is a HVDC link between the static inverter station Loy Yang on the Australian mainland and the static inverter station George Town in Northern Tasmania. ...
The Baltic-Cable is a HVDC power line running beneath the Baltic Sea that interconnects the electric power grids of Germany and Sweden. ...
See also HVDC or high-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power. ...
By traction current one understands the electric current, which is used for the drive of electrical trains. ...
A traction power network is a electricity grid for the supply of electric trains. ...
Transmission lines both generate and absorb reactive power. ...
FACTS (Flexible AC Transmission Systems) is a technology for electric power transmission defined by the IEEE as a power electronic based system and other static equipment that provide control of one or more ac transmission system parameters to enhance controllability and increase power transfer capability. ...
Distributed generation is a new trend in electric power generation. ...
Electricity markets are being developed as a result of the deregulation of electricity utilities around the world. ...
In general, liberalization refers to a relaxation of previous government restrictions, usually in areas of social or economic policy. ...
A lineman is a tradesman who constructs and maintains electric power transmission and distribution facilities. ...
Power line communication (PLC), also called Broadband over Power Lines (BPL) or Power Line Telecoms (PLT), is a wireline method of communication that uses the existing electric power transmission and electricity distribution lines. ...
A pylon is a tall steel lattice structure used to support overhead electricity conductors for power transmission. ...
A submarine communications cable is a cable laid beneath the sea to carry telecommunications between countries. ...
External links Continental Europe is the continent of Europe, explicitly excluding the European islands and peninsulae. ...
The International Agency for Research on Cancer (IARC, or CIRC in its French acronym) is an intergovernmental agency forming part of the World Health Organisation of the United Nations. ...
Lobbying is the practice of private advocacy with the goal of influencing a governing body, in order to ensure that an individuals or organizations point of view is represented in the government. ...
Logo of the GreenFacts website GreenFacts, also known as Green Facts and under its website name greenfacts. ...
References - Grigsby, L. L., et al. The Electric Power Engineering Handbook. USA: CRC Press. (2001). ISBN 0-8493-8578-4
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