Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines that facilitate this movement form a transmission network. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution. The combined transmission and distribution network is part of electricity delivery, known as the electrical grid.
Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket. The abbreviations AC and DC are often used to mean simply alternating and direct, respectively, as when they modify current or voltage.
George Westinghouse Jr. was an American entrepreneur and engineer based in Pennsylvania who created the railway air brake and was a pioneer of the electrical industry, receiving his first patent at the age of 19. Westinghouse saw the potential of using alternating current for electric power distribution in the early 1880s and put all his resources into developing and marketing it. This put Westinghouse's business in direct competition with Thomas Edison, who marketed direct current for electric power distribution. In 1911 Westinghouse received the American Institute of Electrical Engineers's (AIEE) Edison Medal "For meritorious achievement in connection with the development of the alternating current system". He founded the Westinghouse Electric Corporation in 1886.
In electricity generation, a generator is a device that converts motion-based power or fuel-based power into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all the power for electrical grids.
Electric power distribution is the final stage in the delivery of electricity. Electricity is carried from the transmission system to individual consumers. Distribution substations connect to the transmission system and lower the transmission voltage to medium voltage ranging between 2 kV and 33 kV with the use of transformers. Primary distribution lines carry this medium voltage power to distribution transformers located near the customer's premises. Distribution transformers again lower the voltage to the utilization voltage used by lighting, industrial equipment and household appliances. Often several customers are supplied from one transformer through secondary distribution lines. Commercial and residential customers are connected to the secondary distribution lines through service drops. Customers demanding a much larger amount of power may be connected directly to the primary distribution level or the subtransmission level.
An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature. Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used. In principle, any AC electrical generator can be called an alternator, but usually the term refers to small rotating machines driven by automotive and other internal combustion engines.
The war of the currents was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s. It grew out of two lighting systems developed in the late 1870s and early 1880s; arc lamp street lighting running on high-voltage alternating current (AC), and large-scale low-voltage direct current (DC) indoor incandescent lighting being marketed by Thomas Edison's company. In 1886, the Edison system was faced with new competition: an alternating current system initially introduced by George Westinghouse's company that used transformers to step down from a high voltage so AC could be used for indoor lighting. Using high voltage allowed an AC system to transmit power over longer distances from more efficient large central generating stations. As the use of AC spread rapidly with other companies deploying their own systems, the Edison Electric Light Company claimed in early 1888 that high voltages used in an alternating current system were hazardous, and that the design was inferior to, and infringed on the patents behind, their direct current system.
The utility frequency, (power) line frequency or mains frequency is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains electricity by country.
Power engineering, also called power systems engineering, is a subfield of electrical engineering that deals with the generation, transmission, distribution, and utilization of electric power, and the electrical apparatus connected to such systems. Although much of the field is concerned with the problems of three-phase AC power – the standard for large-scale power transmission and distribution across the modern world – a significant fraction of the field is concerned with the conversion between AC and DC power and the development of specialized power systems such as those used in aircraft or for electric railway networks. Power engineering draws the majority of its theoretical base from electrical engineering and mechanical engineering.
Grimeton Radio Station in southern Sweden, close to Varberg in Halland, is an early longwave transatlantic wireless telegraphy station built in 1922–1924, that has been preserved as a historical site. From the 1920s through the 1940s it was used to transmit telegram traffic by Morse code to North America and other countries, and during World War II was Sweden's only telecommunication link with the rest of the world. It is the only remaining example of an early pre-electronic radio transmitter technology called an Alexanderson alternator. It was added to the UNESCO World Heritage List in 2004, with the statement: "Grimeton Radio Station, Varberg is an outstanding monument representing the process of development of communication technology in the period following the First World War." The radio station is also an anchor site for the European Route of Industrial Heritage. The transmitter is still in operational condition, and each year on a day called Alexanderson Day is started up and transmits brief Morse code test transmissions, which can be received all over Europe.
An Alexanderson alternator is a rotating machine invented by Ernst Alexanderson in 1904 for the generation of high-frequency alternating current for use as a radio transmitter. It was one of the first devices capable of generating the continuous radio waves needed for transmission of amplitude modulated signals by radio. It was used from about 1910 in a few "superpower" longwave radiotelegraphy stations to transmit transoceanic message traffic by Morse code to similar stations all over the world.
Galileo Ferraris was an Italian university professor, physicist and electrical engineer, one of the pioneers of AC power system and inventor of the induction motor although he never patented his work. Many newspapers touted that his work on the induction motor and power transmission systems were some of the greatest inventions of all ages. He published an extensive and complete monograph on the experimental results obtained with open-circuit transformers of the type designed by the power engineers Lucien Gaulard and John Dixon Gibbs.
Folsom Powerhouse State Historic Park is a historical site preserving an 1895 alternating current (AC) hydroelectric power station—one of the first in the United States.
Adams Power Plant Transformer House in Niagara Falls, New York is a National Historic Landmarked building constructed in 1895. It is the only remaining structure that was part of the historic Edward Dean Adams Power Plant, the first large-scale, alternating current electric generating plant in the world, built in 1895. The building's eponym was Edward Dean Adams, a businessman and entrepreneur in the electrical field.
An electric power system is a network of electrical components deployed to supply, transfer, and use electric power. An example of a power system is the electrical grid that provides power to homes and industries within an extended area. The electrical grid can be broadly divided into the generators that supply the power, the transmission system that carries the power from the generating centers to the load centers, and the distribution system that feeds the power to nearby homes and industries.
Electric power transmission, the tools and means of moving electricity far from where it is generated, date back to the late 19th century. They include the movement of electricity in bulk and the delivery of electricity to individual customers ("distribution"). In the beginning, the two terms were used interchangeably.
Bridal Veil Falls is a 365-foot waterfall at the end of the box canyon overlooking Telluride, Colorado. Hiking and off-road trails pass by the falls and it has a hydroelectric power plant at its top. In winter the frozen shape of the falls forms an imposing challenge to intrepid ice climbers.
Jaruga Hydroelectric Power Plant is a hydroelectric power plant on river Krka, located in Šibenik-Knin County, in central Dalmatia, Croatia.
The Smuggler-Union Hydroelectric Powerplant, also known as the Bridal Veil Powerhouse, is an electric power generation plant and residence located next to Bridal Veil Falls on a 400-foot (120 m) cliff overlooking Telluride, Colorado. The structure is 2+1⁄2 stories on a poured concrete foundation with a wood frame superstructure. It consists of a main power plant building, a 1+1⁄2-story residence and a 1-story cookhouse. The power plant foundation is distinctive, with semicircular windows. A semicircular bay with arched windows projects out on a rock spur.
Single-phase generator is an alternating current electrical generator that produces a single, continuously alternating voltage. Single-phase generators can be used to generate power in single-phase electric power systems. However, polyphase generators are generally used to deliver power in three-phase distribution system and the current is converted to single-phase near the single-phase loads instead. Therefore, single-phase generators are found in applications that are most often used when the loads being driven are relatively light, and not connected to a three-phase distribution, for instance, portable engine-generators. Larger single-phase generators are also used in special applications such as single-phase traction power for railway electrification systems.
