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Superconducting Magnetic Energy Storage
Superconducting magnetic energy storage (SMES) systems store energy in the magnetic field created by the flow of direct current in a superconducting coil that has been cryogenically cooled to a temperature below its superconducting critical temperature. This use of superconducting coils to store magnetic energy was invented by M. Ferrier in 1970. A typical SMES system includes three parts: superconducting coil, power conditioning system and cryogenically cooled refrigerator. Once the superconducting coil is energized, the current will not decay and the magnetic energy can be stored indefinitely. The stored energy can be released back to the network by discharging the coil. The power conditioning system uses an inverter/rectifier to transform alternating current (AC) power to direct current or convert DC back to AC power. The inverter/rectifier accounts for about 2–3% energy loss in each direction. SMES loses the least amount of electricity in the energy storage process c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watt Hour
A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a SI unit, non-SI Units of measurement, unit of energy equal to 3.6 megajoules (MJ) in SI units, which is the energy delivered by one kilowatt of power for one hour. Kilowatt-hours are a common billing unit for electrical energy supplied by electric utilities. Metric prefixes are used for multiples and submultiples of the basic unit, the watt-hour (3.6 kJ). Definition The kilowatt-hour is a composite unit of energy equal to one kilowatt (kW) multiplied by (i.e., sustained for) one hour. The International System of Units (SI) unit of energy meanwhile is the joule (symbol J). Because a watt is by definition one joule per second, and because there are 3,600 seconds in an hour, one kWh equals 3,600 kilojoules or 3.6 MJ."Half-high dots or spaces are used to express a derived unit formed from two or more other units by multiplication.", Barry N. Taylor. (2001 ed.''The International System of Units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current (electricity)
An electric current is a flow of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is defined as the net rate of flow of electric charge through a surface. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In an electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons. In the International System of Units (SI), electric current is expressed in units of ampere (sometimes called an "amp", symbol A), which is equivalent to one coulomb per second. The ampere is an SI base unit and electric current is a base quantity in the International System of Quantities (ISQ). Electric current is also known as amperage and is measured using a device called an ''ammeter''. Electric currents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mean
A mean is a quantity representing the "center" of a collection of numbers and is intermediate to the extreme values of the set of numbers. There are several kinds of means (or "measures of central tendency") in mathematics, especially in statistics. Each attempts to summarize or typify a given group of data, illustrating the magnitude and sign of the data set. Which of these measures is most illuminating depends on what is being measured, and on context and purpose. The ''arithmetic mean'', also known as "arithmetic average", is the sum of the values divided by the number of values. The arithmetic mean of a set of numbers ''x''1, ''x''2, ..., x''n'' is typically denoted using an overhead bar, \bar. If the numbers are from observing a sample of a larger group, the arithmetic mean is termed the '' sample mean'' (\bar) to distinguish it from the group mean (or expected value) of the underlying distribution, denoted \mu or \mu_x. Outside probability and statistics, a wide rang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross Section (geometry)
In geometry and science, a cross section is the non-empty intersection (set theory), intersection of a solid body in three-dimensional space with a Plane (geometry), plane, or the analog in higher-dimensional spaces. Cutting an object into slices creates many parallel cross-sections. The boundary of a cross-section in three-dimensional space that is parallel to two of the Cartesian coordinate system, axes, that is, parallel to the plane determined by these axes, is sometimes referred to as a contour line; for example, if a plane cuts through mountains of a raised-relief map parallel to the ground, the result is a contour line in two-dimensional space showing points on the surface of the mountains of equal elevation. In technical drawing a cross-section, being a Planar projection, projection of an object onto a plane that intersects it, is a common tool used to depict the internal arrangement of a 3-dimensional object in two dimensions. It is traditionally crosshatched with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rectangle
In Euclidean geometry, Euclidean plane geometry, a rectangle is a Rectilinear polygon, rectilinear convex polygon or a quadrilateral with four right angles. It can also be defined as: an equiangular quadrilateral, since equiangular means that all of its angles are equal (360°/4 = 90°); or a parallelogram containing a right angle. A rectangle with four sides of equal length is a ''square''. The term "wikt:oblong, oblong" is used to refer to a non-square rectangle. A rectangle with Vertex (geometry), vertices ''ABCD'' would be denoted as . The word rectangle comes from the Latin ''rectangulus'', which is a combination of ''rectus'' (as an adjective, right, proper) and ''angulus'' (angle). A #Crossed rectangles, crossed rectangle is a crossed (self-intersecting) quadrilateral which consists of two opposite sides of a rectangle along with the two diagonals (therefore only two sides are parallel). It is a special case of an antiparallelogram, and its angles are not right angles an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cylinder (geometry)
A cylinder () has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite curvilinear surface in various modern branches of geometry and topology. The shift in the basic meaning—solid versus surface (as in a solid ball versus sphere surface)—has created some ambiguity with terminology. The two concepts may be distinguished by referring to solid cylinders and cylindrical surfaces. In the literature the unadorned term "cylinder" could refer to either of these or to an even more specialized object, the '' right circular cylinder''. Types The definitions and results in this section are taken from the 1913 text ''Plane and Solid Geometry'' by George A. Wentworth and David Eugene Smith . A ' is a surface consisting of all the points on all the lines which are parallel to a given line and which pass through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ampere
The ampere ( , ; symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. is the unit of electric current in the International System of Units (SI). One ampere is equal to 1 coulomb (C) moving past a point per second. It is named after French mathematician and physicist André-Marie Ampère (1775–1836), considered the father of electromagnetism along with Danish physicist Hans Christian Ørsted. As of the 2019 revision of the SI, the ampere is defined by fixing the elementary charge to be exactly , which means an ampere is an electric current equivalent to elementary charges moving every seconds, or approximately elementary charges moving in a second. Prior to the redefinition, the ampere was defined as the current passing through two parallel wires 1 metre apart that produces a magnetic force of newtons per metre. The earlier CGS system has two units of current, one structured similarly to the S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry (unit)
The henry (symbol: H) is the unit of electrical inductance in the International System of Units (SI), defined as 1 kg⋅ m2⋅ s−2⋅ A−2. If a current of 1 ampere flowing through a coil produces flux linkage of 1 weber turn, that coil has a self-inductance of 1 henry. The unit is named after Joseph Henry (1797–1878), the American scientist who discovered electromagnetic induction independently of and at about the same time as Michael Faraday (1791–1867) in England. Definition The inductance of an electric circuit is one henry when an electric current that is changing at one ampere per second results in an electromotive force of one volt The volt (symbol: V) is the unit of electric potential, Voltage#Galvani potential vs. electrochemical potential, electric potential difference (voltage), and electromotive force in the International System of Units, International System of Uni ... across the inductor: V(t)= L \frac\,, where is the resulting voltage ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joule
The joule ( , or ; symbol: J) is the unit of energy in the International System of Units (SI). In terms of SI base units, one joule corresponds to one kilogram- metre squared per second squared One joule is equal to the amount of work done when a force of one newton displaces a body through a distance of one metre in the direction of that force. It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889). Definition According to the International Bureau of Weights and Measures the joule is defined as "the work done when the point of application of 1 MKS unit of force ewtonmoves a distance of 1 metre in the direction of the force." In terms of SI base units and in terms of SI derived units with special names, the joule is defined as One joule is also equivalent to any of the following: * The work required to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromotive Force
In electromagnetism and electronics, electromotive force (also electromotance, abbreviated emf, denoted \mathcal) is an energy transfer to an electric circuit per unit of electric charge, measured in volts. Devices called electrical ''transducers'' provide an emf by Energy transformation, converting other forms of energy into electrical energy. Other types of electrical equipment also produce an emf, such as Battery (electricity), batteries, which convert chemical energy, and Electric generator, generators, which convert mechanical energy. This energy conversion is achieved by Force, physical forces applying Work (physics), physical work on electric charges. However, electromotive force itself is not a physical force, and ISO/International Electrotechnical Commission, IEC standards have deprecated the term in favor of source voltage or source tension instead (denoted U_s). An Hydraulic analogy, electronic–hydraulic analogy may view emf as the mechanical work done to water by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wisconsin
Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. With a population of about 6 million and an area of about 65,500 square miles, Wisconsin is the List of U.S. states and territories by population, 20th-largest state by population and the List of U.S. states and territories by area, 23rd-largest by area. It has List of counties in Wisconsin, 72 counties. Its List of municipalities in Wisconsin by population, most populous city is Milwaukee; its List of capitals in the United States, capital and second-most populous city is Madison, Wisconsin, Madison. Other urban areas include Green Bay, Wisconsin, Green Bay, Kenosha, Wisconsin, Kenosha, Racine, Wisconsin, Racine, Eau Claire, Wisconsin, Eau Claire, and the Fox Cities. Geography of Wiscon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
