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Reactive Power Management
Voltage control and reactive power management are two facets of an ancillary service that enables reliability of the transmission networks and facilitates the electricity market on these networks. Both aspects of this activity are intertwined (voltage change in an alternating current (AC) network is effected through production or absorption of reactive power), so within this article the term ''voltage control'' will be primarily used to designate this essentially single activity, as suggested by Kirby & Hirst (1997). Voltage control does not include reactive power injections to dampen the grid oscillations; these are a part of a separate ancillary service, so-called system stability service. The transmission of reactive power is limited by its nature, so the voltage control is provided through pieces of equipment distributed throughout the power grid, unlike the frequency control that is based on maintaining the overall active power balance in the system. Need for voltage con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancillary Service
Ancillary services are the services necessary to support the transmission of electric power from power plant, generators to consumers given the obligations of control areas and transmission utilities within those control areas to maintain reliable operations of the interconnected Electric power transmission, transmission system. "Ancillary services are all services required by the transmission or distribution system operator to enable them to maintain the integrity and stability of the transmission or distribution system as well as the power quality". Ancillary services are specialty services and functions provided by actors within the electric grid that facilitate and support the continuous flow of electricity, so that the demand for electrical energy is met in real time. The term ancillary services is used to refer to a variety of operations beyond Electric power generation, generation and Electric power transmission, transmission that are required to maintain grid stability and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inductor
An inductor, also called a coil, choke, or reactor, is a Passivity (engineering), passive two-terminal electronic component, electrical component that stores energy in a magnetic field when an electric current flows through it. An inductor typically consists of an insulated wire wound into a Electromagnetic coil, coil. When the current flowing through the coil changes, the time-varying magnetic field induces an electromotive force (''emf'') (voltage) in the conductor, described by Faraday's law of induction. According to Lenz's law, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, inductors oppose any changes in current through them. An inductor is characterized by its inductance, which is the ratio of the voltage to the rate of change of current. In the International System of Units (SI), the unit of inductance is the Henry (unit), henry (H) named for 19th century American scientist Joseph Henry. In the measurement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shunt (electrical)
A shunt is a device that is designed to provide a low-resistance path for an electrical current in a Electrical network, circuit. It is typically used to divert current away from a system or Electronic component, component in order to prevent overcurrent. Electrical shunts are commonly used in a variety of applications including power distribution systems, electrical measurement systems, automotive and marine applications. Defective device bypass One example is in miniature Christmas lights (holiday decoration), Christmas lights which are series circuit, wired in series. When the Electrical filament, filament burns out in one of the incandescent light bulbs, the full line voltage appears across the burnt out bulb. A shunt resistor, which has been connected parallel circuits, in parallel across the filament before it burnt out, will then short out to bypass the burnt filament and allow the rest of the string to light. If too many lights burn out however, a shunt will also burn o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excitation (magnetic)
In electromagnetism, excitation is the process of generating a magnetic field by means of an electric current. An electric generator or electric motor consists of a rotor spinning in a magnetic field. The magnetic field may be produced by permanent magnets or by field coils. In the case of a machine with field coils, a current must flow in the coils to generate (''excite'') the field, otherwise no power is transferred to or from the rotor. Field coils yield the most flexible form of magnetic flux regulation and de-regulation, but at the expense of a flow of electric current. Hybrid topologies exist, which incorporate both permanent magnets and field coils in the same configuration. The flexible excitation of a rotating electrical machine is employed by either brushless excitation techniques or by the injection of current by carbon brushes (static excitation). Excitation in generators For a machine using field coils, as is the case in most large generators, the fie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incandescent Lamp
An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a filament until it glows. The filament is enclosed in a glass bulb that is either evacuated or filled with inert gas to protect the filament from oxidation. Electric current is supplied to the filament by terminals or wires embedded in the glass. A bulb socket provides mechanical support and electrical connections. Incandescent bulbs are manufactured in a wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, and work equally well on either alternating current or direct current. As a result, the incandescent bulb became widely used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, and flashlights, and for decorative and advertising lighting. Incandescent b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washing Machine
A washing machine (laundry machine, clothes washer, washer, or simply wash) is a machine designed to laundry, launder clothing. The term is mostly applied to machines that use water. Other ways of doing laundry include dry cleaning (which uses alternative cleaning fluids and is performed by specialist businesses) and ultrasonic cleaning. Modern-day home appliances use electric power to automatically clean clothes. The user adds laundry detergent, which is sold in liquid, powder, or dehydrated sheet form, to the wash water. The machines are also found in commercial laundromats where customers pay-per-use. History Washing by hand Laundering by hand involves soaking, beating, scrubbing, and rinsing dirty textiles. Before indoor plumbing, it was necessary to carry all the water used for washing, boiling, and rinsing the laundry from a pump, Water well, well, or Spring (hydrology), spring. Water for the laundry would be hand-carried, heated on a fire for washing, and then poured i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Load
An electrical load is an electrical component or portion of a Electric Circuit, circuit that consumes (active) electric power, such as electrical appliances and Electric light, lights inside the home. The term may also refer to the power Power consumption, consumed by a circuit. This is opposed to a power supply source, such as a Electric battery, battery or Electric generator, generator, which ''provides'' power. The term is used more broadly in electronics for a device connected to a electrical signal, signal source, whether or not it consumes power. If an electric circuit has an output port (circuit theory), port, a pair of terminals that produces an electrical signal, the circuit connected to this terminal (or its input Electrical impedance, impedance) is the ''load''. For example, if a CD player is connected to an amplifier, the CD player is the source, and the amplifier is the load, and to continue the concept, if loudspeakers are connected to that amplifier, then that ampli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underground Power Lines
An underground power line provides electrical power with underground cables. Compared to overhead power lines, underground lines have lower risk of starting a wildfire and reduce the risk of the electrical supply being interrupted by outages during high winds, thunderstorms or heavy snow or ice storms. An added benefit of undergrounding is the aesthetic quality of the landscape without the powerlines. Undergrounding can increase the capital cost of electric power transmission and distribution but may decrease operating costs over the lifetime of the cables. History Early undergrounding had a basis in the detonation of mining explosives and in undersea telegraph cables. Electric cables were used in Russia to detonate mining explosives in 1812, and to carry telegraph signals across the English Channel in 1850. With the spread of early electrical power systems, undergrounding began to increase as well. Thomas Edison used underground DC “street pipes” in his early electric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surge Impedance
The characteristic impedance or surge impedance (usually written Z0) of a uniform transmission line is the ratio of the amplitudes of voltage and current of a wave travelling in one direction along the line in the absence of reflections in the other direction. Equivalently, it can be defined as the input impedance of a transmission line when its length is infinite. Characteristic impedance is determined by the geometry and materials of the transmission line and, for a uniform line, is not dependent on its length. The SI unit of characteristic impedance is the ohm. The characteristic impedance of a lossless transmission line is purely real, with no reactive component (see below). Energy supplied by a source at one end of such a line is transmitted through the line without being dissipated in the line itself. A transmission line of finite length (lossless or lossy) that is terminated at one end with an impedance equal to the characteristic impedance appears to the source like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overhead Power Lines
An overhead power line is a structure used in electric power transmission and Electric power distribution, distribution to transmit electrical energy along large distances. It consists of one or more electrical conductor, conductors (commonly multiples of three) suspended by Transmission tower, towers or Utility pole, poles. Since the surrounding air provides good cooling, electrical insulation, insulation along long passages, and allows optical inspection, overhead power lines are generally the lowest-cost method of power transmission for large quantities of electric energy. Construction Towers for support of the lines are made of wood (as-grown or laminated), steel or aluminum (either lattice structures or tubular poles), concrete, and occasionally reinforced plastics. The bare wire conductors on the line are generally made of aluminum (either plain or ACSR, reinforced with steel, or composite materials such as carbon and glass fiber), though some copper wires are used in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transformer
In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer's core, which induces a varying electromotive force, electromotive force (EMF) across any other coils wound around the same core. Electrical energy can be transferred between separate coils without a metallic (conductive) connection between the two circuits. Faraday's law of induction, discovered in 1831, describes the induced voltage effect in any coil due to a changing magnetic flux encircled by the coil. Transformers are used to change Alternating current, AC voltage levels, such transformers being termed step-up or step-down type to increase or decrease voltage level, respectively. Transformers can also be used to provide galvanic isolation between circuits as well as to couple stages of signa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
