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For the magazine, see Power Engineering (magazine). Power Engineering is a magazine dedicated to professionals in the field of Power engineering and Power generation.
A steam turbine used to provide electric power.
A steam turbine used to provide electric power.

Power engineering, also called power systems engineering, is a subfield of electrical engineering that deals with the generation, transmission and distribution of electric power as well as the electrical devices connected to such systems including generators, motors and transformers. Electrical engineering, sometimes referred to as electrical and electronic engineering, is a field of Engineering that deals with the study and application of Electricity generation is the process of converting non-electrical Energy to Electricity. Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power Electricity distribution is the penultimate stage in the delivery (before retail) of Electricity to end users Electric power is defined as the rate at which Electrical energy is transferred by an Electric circuit. In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic An electric motor uses Electrical energy to produce Mechanical energy. A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors 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 as well as the development of specialised power systems such as those used in aircraft or for electric railway networks. This article deals with where how and why "three phase" is used A rectifier is an electrical device that converts Alternating current (AC to Direct current (DC a process known as rectification.

Contents

History

Electricity became a subject of scientific interest in the late 17th century with the work of William Gilbert. William Gilbert, also known as Gilbard ( Colchester, England, May 24, 1544 &ndash London, England, November 30 [1] Over the next two centuries a number of important discoveries were made including the incandescent lightbulb and the voltaic pile. The incandescent light bulb, incandescent lamp or incandescent light globe is a source of electric Light that works by Incandescence, (a general A voltaic pile is a set of individual Voltaic cells placed in series [2][3] Probably the greatest discovery with respect to power engineering came from Michael Faraday who in 1831 discovered that a change in magnetic flux induces an electromotive force in a loop of wire—a principle known as electromagnetic induction that helps explain why generators and transformers work. Michael Faraday, FRS ( September 22 1791 – August 25 1867) was an English Electromotive force ( emf, \mathcal{E} is a term used to characterize electrical devices such as Voltaic cells thermoelectric devices electrical Faraday's law of induction describes an important basic law of electromagnetism which is involved in the working of Transformers Inductors and many forms of [4]

In 1882 Thomas Edison and his company, The Edison Electric Light Company, developed the world's first central electric power station on Pearl Street in New York City. The Pearl Street Station consisted of several steam-powered generators and initially powered around 3,000 lamps for 59 customers. Pearl Street Station was the first central power plant in the United States [5][6] The power station used direct current and operated at a single voltage. Direct current ( DC) is the unidirectional flow of Electric charge. Since the direct current power could not be easily transformed to the higher voltages necessary to minimise power loss, the possible distance between the generators and load was limited to around half-a-mile (800 metres). [7]

That same year in London Lucien Gaulard and John Dixon Gibbs demonstrated the first transformer suitable for use in a real power system. Lucien Gaulard ( 1850 - November 26, 1888) invented devices for the transmission of Alternating current Electrical Energy The practical value of Gaulard and Gibbs' transformer was demonstrated in 1884 at Turin where the transformer was used to light up forty kilometres (25 miles) of railway from a single alternating current generator. An alternating current ( AC) is an Electric current whose direction reverses cyclically as opposed to Direct current, whose direction remains constant [8] Despite the success of the system, the pair made some fundamental mistakes. Perhaps the most serious was connecting the primaries of the transformers in series so that switching one lamp on or off would affect other lamps further down the line. If two or more circuit components are connected end to end like a daisy chain it is said they are connected in series. Following the demonstration George Westinghouse, an American entrepreneur, imported a number of the transformers along with a Siemens generator and set his engineers to experimenting with them in the hopes of improving them for use in a commercial power system. George Westinghouse Jr ( 6 October 1846 &ndash 12 March 1914) was an American Entrepreneur and Engineer

One of Westinghouse's engineers, William Stanley, recognised the problem with connecting transformers in series as opposed to parallel and also realised that making the iron core of a transformer a fully-enclosed loop would improve the voltage regulation of the secondary winding. William Stanley may refer to Sir William Stanley (Battle of Bosworth (?-1495 brother of Thomas Stanley 1st Earl of Derby Sir William Stanley If two or more circuit components are connected end to end like a daisy chain it is said they are connected in series. In Electrical engineering, particularly Power engineering, voltage regulation is the ability of a system to provide near constant Voltage over a wide range Using this knowledge he built a much improved alternating current power system at Great Barrington, Massachusetts in 1886. Great Barrington is the name of more than one place Great Barrington Gloucestershire in England Great Barrington Massachusetts The Commonwealth of Massachusetts ( is a state located in the New England region of the northeastern United States. [9] Then in 1887 and 1888 another engineer called Nikola Tesla filed a range of patents related to power systems including one for a two-phase induction motor. There have already been discussions about Tesla's ethnicity on the talk page An induction motor (IM is a type of asynchronous AC motor where power is supplied to the rotating device by means of electromagnetic induction. Although Tesla cannot necessarily be attributed with building the first induction motor, his design, unlike others, was practical for industrial use. [10]

By 1890 the power industry had flourished and power companies had built literally thousands of power systems (both direct and alternating current) in the United States and Europe - these networks were effectively dedicated to providing electric lighting. During this time a fierce rivalry known as the "War of Currents" emerged between Edison, Westinghouse and Tesla over which form of transmission (direct or alternating current) was superior. In the "War of Currents" era (sometimes "War of the Currents" or "Battle of Currents") in the late 1880s George Westinghouse In 1891, Westinghouse installed the first major power system that was designed to drive an electric motor and not just provide electric lighting. The installation powered a 100-horsepower synchronous motor at Telluride, Colorado with the motor being started by a Tesla induction motor. The Town of Telluride is a Home Rule Municipality that is the County seat and the most populous town of San Miguel County in the southwestern [11] On the other side of the Atlantic, Oskar von Miller built a 20 kV 176 km three-phase transmission line from Lauffen am Neckar to Frankfurt am Main for the Electrial Engineering Exhibition in Frankfurt. Oskar von Miller ( 7 May 1855 &ndash 9 April 1934 was a German engineer and founder of the Deutsches Museum, a large museum of technology Lauffen is a town in the district of Heilbronn, Baden-Württemberg, Germany. [12] In 1895, after a protracted decision-making process, the Adams No. 1 generating station at Niagara Falls began transferring three-phase alternating current power to Buffalo at 11 kV. The Niagara Falls are massive Waterfalls on the Niagara River, straddling the international border separating the Canadian province of Ontario Following completion of the Niagara Falls project, new power systems increasingly chose alternating current as opposed to direct current for electrical transmission. An alternating current ( AC) is an Electric current whose direction reverses cyclically as opposed to Direct current, whose direction remains constant Direct current ( DC) is the unidirectional flow of Electric charge. [13]

Although the 1880s and 1890s were seminal decades in the field, developments in power engineering continued throughout the 20th and 21st century. In 1936 the first commercial HVDC (high voltage direct current) line using Mercury arc valves was built between Shenectady and Mechanicville. HVDC or high-voltage Direct current Electric power transmission systems contrast with the more common Alternating current systems as a means A mercury arc valve ( mercury vapor rectifier) is a type of electrical Rectifier which converts alternating current into Direct current. Mechanicville is a City in Saratoga County, New York, United States. HVDC had previously been achieved by installing direct current generators in series (known as the Thury system) although this system suffered from serious reliability issues. [14] In 1957 Siemens demonstrated the first solid-state rectifier (solid-state rectifiers are now the standard for HVDC systems) however it was not until the early 1970s that this technology was used in commercial power systems. [15] In 1959 Westinghouse demonstrated the first circuit breaker that used SF6 as the interrupting medium. A circuit breaker is an automatically-operated electrical Switch designed to protect an electrical circuit from damage caused by overload or Sulfur hexafluoride is an Inorganic compound with the formula. [16] SF6 is a far superior dielectric to air and, in recent times, its use has been extended to produce far more compact switching equipment (known as switchgear) and transformers. A dielectric is a nonconducting substance ie an insulator. The term was coined by William Whewell in response to a request from Michael Faraday. The term switchgear, used in association with the electric power system or grid refers to the combination of electrical disconnects fuses and/or Circuit breakers A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors [17][18] Many important developments also came from extending innovations in the information technology and telecommunications field to the power engineering field. Information and Communications Technology - or technologies ( ICT) is an umbrella term that includes all technologies for the manipulation and communication of Information For example, the development of computers allowed for load flow studies to be run efficiently allowing for much better planning of power systems. In Power engineering, the power flow study (also known as load-flow study) is an important tool involving Numerical analysis applied to a power system Advances in information technology and telecommunication also allowed for much better remote control of the power system's switchgear and generators.

Power

Transmission lines transmit power across the grid.
Transmission lines transmit power across the grid. Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power

Power Engineering deals with the generation, transmission and distribution of electricity as well as the design of a range of related devices. Electricity generation is the process of converting non-electrical Energy to Electricity. Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power Electricity distribution is the penultimate stage in the delivery (before retail) of Electricity to end users These include transformers, electric generators, electric motors and power electronics. A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic An electric motor uses Electrical energy to produce Mechanical energy. This article refers to the technology of power electronics For the musical genre see power electronics Power electronics is the applications

In many regions of the world, governments maintain an electrical network that connects a variety electric generators together with users of their power. This network is called a power grid. Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power Users purchase electricity from the grid avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it. Such systems are called on-grid power systems and may supply the grid with additional power, draw power from the grid or do both.

Power engineers may also work on systems that do not connect to the grid. These systems are called off-grid power systems and may be used in preference to on-grid systems for a variety of reasons. For example, in remote locations it may be cheaper for a mine to generate its own power rather than pay for connection to the grid and in most mobile applications connection to the grid is simply not practical.

Today, most grids adopt three-phase electric power with alternating current. This article deals with where how and why "three phase" is used An alternating current ( AC) is an Electric current whose direction reverses cyclically as opposed to Direct current, whose direction remains constant This choice can be partly attributed to the ease with which this type of power can be generated, transformed and used. Often (especially in the USA), the power is split before it reaches residential customers whose low-power appliances rely upon single-phase electric power. The United States of America —commonly referred to as the In electrical engineering single-phase electric power refers to the distribution of Alternating current Electric power using a system in which all the voltages of However, many larger industries and organizations still prefer to receive the three-phase power directly because it can be used to drive highly efficient electric motors such as three-phase induction motors. An induction motor (IM is a type of asynchronous AC motor where power is supplied to the rotating device by means of electromagnetic induction.

Transformers play an important role in power transmission because they allow power to be converted to and from higher voltages. A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power Electrical tension (or voltage after its SI unit, the Volt) is the difference of electrical potential between two points of an electrical This is important because higher voltages suffer less power loss during transmission. Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power This is because higher voltages allow for lower current to deliver the same amount of power as power is the product of the two. Thus, as the voltage steps up, the current steps down. It is the current flowing through the components that result in both the losses and the subsequent heating. These losses, appearing in the form of heat, are equal to the current squared times the electrical resistance through which the current flows, so as the voltage goes up the losses are dramatically reduced.

For these reasons, electrical substations exist throughout power grids to convert power to higher voltages before transmission and to lower voltages suitable for appliances after transmission. An electrical substation is a subsidiary station of an Electricity generation, transmission and distribution system where Voltage

Components

Power engineering is a network of interconnected components which convert different forms of energy to electrical energy. Modern power engineering consists of three main subsystems: the generation subsystem, the transmission subsystem, and the distribution subsystem. In the generation subsystem, the power plant produces the electricity. The transmission subsystem transmits the electricity to the load centers. The distribution subsystem continues to transmit the power to the customers.

Generation

Generation of electrical power is a process whereby energy is transformed into an electrical form. There are several different transformation processes, among which are chemical, photo-voltaic, and electromechanical. Electromechanical energy conversion is used in converting energy from coal, petroleum, natural gas, uranium, water flow, and wind into electrical energy. Petroleum ( L petroleum, from Greek πετρέλαιον, lit Natural gas is a Gaseous Fossil fuel consisting primarily of Methane but including significant quantities of Ethane, Propane, Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Of these, all except the wind energy conversion process take advantage of the synchronous AC generator coupled to a steam, gas or hydro turbine such that the turbine converts steam, gas, or water flow into rotational energy, and the the synchronous generator then converts the rotational energy of the turbine into electrical energy. It is the turbine-generator conversion process that is by far most economical and consequently most common in the industry today.

The AC synchronous machine is the most common technology for generating electrical energy. It is called synchronous because the composite magnetic field produced by the three stator windings rotate at the same speed as the magnetic field produced by the field winding on the rotor. The stator is the stationary part of an Electric generator or Electric motor. A simplified circuit model is used to analyze steady-state operating conditions for a synchronous machine. Steady state is a more general situation than Dynamic equilibrium. The phaser diagram is an effective tool for visualizing the relationships between internal voltage, armature current, and terminal voltage. The excitation control system is used on synchronous machines to regulate terminal voltage, and the turbine-governor system is used to regulate the speed of the machine.

The operating costs of generating electrical energy is determined by the fuel cost and the efficiency of the power station. A power station (also referred to as generating station, power plant or powerhouse) is an industrial facility for the generation of The efficiency depends on generation level and can be obtained from the heat rate curve. We may also obtain the incremental cost curve from the heat rate curve. Economic dispatch is the process of allocating the required load demand between the available generation units such that the cost of operation is minimized.

Transmission

The electricity is transported to load locations from a power station to a transmission subsystem. A power station (also referred to as generating station, power plant or powerhouse) is an industrial facility for the generation of Therefore we may think of the transmission system as providing the medium of transportation for electric energy. The transmission system may be subdivided into the bulk transmission system and the sub-transmission system. The functions of the bulk transmission are to interconnect generators, to interconnect various areas of the network, and to transfer electrical energy from the generators to the major load centers. This portion of the system is called "bulk" because it delivers energy only to so-called bulk loads such as the distribution system of a town, city, or large industrial plant. The function of the sub-transmission system is to interconnect the bulk power system with the distribution system.


Transmission circuits may be built either underground or overhead. Underground cables are used predominantly in urban areas where acquisition of overhead rights of way are costly or not possible. They are also used for transmission under rivers, lakes and bays. Overhead transmission is used otherwise because, for a given voltage level, overhead conductors are much less expensive than underground cables.


The transmission system is a highly integrated system. It is referred to the substation equipment and transmission lines. The substation equipment contain the transformers, relays, and circuit breakers. A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors A relay is an electrical Switch that opens and closes under the control of another Electrical circuit. A circuit breaker is an automatically-operated electrical Switch designed to protect an electrical circuit from damage caused by overload or Transformers are important static devices which transfer electrical energy from one circuit with another in the transmission subsystem. A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors Transformers are used to step up the voltage on the transmission line to reduce the power loss which is dissipated on the way. [19] A relay is functionally a level-detector; they perform a switching action when the input voltage (or current) meets or exceeds a specific and adjustable value. A relay is an electrical Switch that opens and closes under the control of another Electrical circuit. A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. A circuit breaker is an automatically-operated electrical Switch designed to protect an electrical circuit from damage caused by overload or A change in the status of any one component can significantly affect the operation of the entire system. There are three possible causes for power flow limitations to a transmission line. These causes are thermal overload, voltage instability, and rotor angle instability. Thermal overload is caused by excessive current flow in a circuit causing overheating. Voltage instabiliy is said to occur when the power required to maintain voltages at or above acceptable levels exceeds the available power. Rotor angle instability is a dynamic problem that may occur following faults, such as short circuit, in the transmission system. It may also occur tens of seconds after a fault due to poorly damped or undamped oscillatory response of the rotor motion.

Distribution

The distribution system transports the power from the transmission system to the customer. The distribution systems are typically radial because networked systems are more expensive. The equipment associated with the distribution system includes the substation transformers connected to the transmission systems, the distribution lines from the transformers to the customers and the protection and control equipment between the transformer and the customer. The protection equipment includes lightning protectors, circuit breakers, disconnectors and fuses. The control equipment includes voltage regulators, capacitors, and demand side management equipment.

See also

References

  1. ^ Pioneers in Electricity and Magnetism: William Gilbert. Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power Energy economics is a broad scientific subject area which includes topics related to supply and use of Energy in societies. In Engineering, Fault-tolerant design, also known as fail-safe design, is a design that enables a system to continue operation possibly at a reduced level (also known Electricity distribution is the penultimate stage in the delivery (before retail) of Electricity to end users This article refers to the technology of power electronics For the musical genre see power electronics Power electronics is the applications Electricity generation is the process of converting non-electrical Energy to Electricity. A stationary engineer is a licensed operator of boilers steam turbines auxiliary equipment (ie National High Magnetic Field Laboratory. Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  2. ^ The History Of The Light Bulb. Net Guides Publishing, Inc. (2004). Retrieved on 2007-05-02. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1194 - King Richard I of England gives Portsmouth its first Royal Charter.
  3. ^ Greenslade, Thomas. The Voltaic Pile. Kenyon College. Retrieved on 2008-03-31. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 307 - After divorcing his wife Minervina, Constantine marries Fausta, the daughter of the retired Roman Emperor
  4. ^ Faraday Page. The Royal Institute. Retrieved on 2008-03-31. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 307 - After divorcing his wife Minervina, Constantine marries Fausta, the daughter of the retired Roman Emperor
  5. ^ Williams, Jasmin. Edison Lights The City. New York Post. Retrieved on 2008-03-31. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 307 - After divorcing his wife Minervina, Constantine marries Fausta, the daughter of the retired Roman Emperor
  6. ^ Grant, Casey. The Birth of NFPA. National Fire Protection Association. Retrieved on 2008-03-31. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 307 - After divorcing his wife Minervina, Constantine marries Fausta, the daughter of the retired Roman Emperor
  7. ^ New York Independent System Operator. "Bulk Electricity Grid Beginnings". Press release. A news release, media release, press release or press statement is a written or recorded Communication directed at members of the News Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  8. ^ Katz, Evgeny (2007-04-08). Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 217 - Roman Emperor Caracalla is Assassinated (and succeeded by his Praetorian Lucien Gaulard. Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  9. ^ Blalock, Thomas (2004-10-02). "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 1187 - Siege of Jerusalem: Saladin captures Jerusalem after 88 years of Crusader rule Alternating Current Electrification, 1886. Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  10. ^ Petar Miljanic, Tesla's Polyphase System and Induction Motor, Serbian Journal of Electrical Engineering, p121-130, Vol. 3, No. 2, November 2006.
  11. ^ Foran, Jack. The Day They Turned The Falls On. Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  12. ^ Voith Siemens (company) (2007-02-01). HyPower, p. 7.  
  13. ^ Adams Hydroelectric Generating Plant, 1895. IEEE. Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  14. ^ A Novel but Short-Lived Power Distribution System. IEEE (2005-05-01). Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Events 305 - Diocletian and Maximian retire from the office of Roman Emperor. Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  15. ^ Gene Wolf. "Electricity Through the Ages", Transmission & Distribution World, 2000-12-01. 2000 ( MM) was a Leap year that started on Saturday of the Common Era, in accordance with the Gregorian calendar. Events 800 - Charlemagne judges the accusations against Pope Leo III in the Vatican  
  16. ^ John Tyner, Rick Bush and Mike Eby. "A Fifty-Year Retrospective", Transmission & Distribution World, 1999-11-01. Year 1999 ( MCMXCIX) was a Common year starting on Friday (link will display full 1999 Gregorian calendar) Events 996 - Emperor Otto III issues a deed to Gottschalk Bishop of Freising which is the oldest known document using the name Ostarrîchi  
  17. ^ Gas Insulated Switchgear. ABB. Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  18. ^ Amin, Sayed. SF6 Transformer. Retrieved on 2008-05-25. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  19. ^ Transformers

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