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Shunt Reactor
In an electric power transmission grid system, switchyard reactors are large inductors installed at substations to help stabilize the power system. For transmission lines, the space between the overhead line and the ground forms a capacitor parallel to transmission line, which causes an increase in voltage as the distance increases. To offset the capacitive effect of the transmission line and to regulate the voltage and reactive power of the power system, reactors are connected either at line terminals or at the middle, thereby improving the voltage profile of transmission line. In large systems with many generators connected in parallel, it may be necessary to use a series reactor to prevent excessively large current flow during a short circuit; this protects transmission line conductors and switching apparatus from damage due to high currents and forces produced during a short circuit. A shunt reactor is connected in parallel with a transmission line or other load. A series re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Grid
An electrical grid (or electricity network) is an interconnected network for electricity delivery from producers to consumers. Electrical grids consist of power stations, electrical substations to step voltage up or down, electric power transmission to carry power over long distances, and finally electric power distribution to customers. In that last step, voltage is stepped down again to the required service voltage. Power stations are typically built close to energy sources and far from densely populated areas. Electrical grids vary in size and can cover whole countries or continents. From small to large there are microgrids, wide area synchronous grids, and super grids. The combined transmission and distribution network is part of electricity delivery, known as the ''power grid''. Grids are nearly always synchronous, meaning all distribution areas operate with three phase alternating current (AC) frequencies synchronized (so that voltage swings occur at almost the same ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Line
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] |
Static VAR Compensator
In electrical engineering, a static VAR compensator (SVC) is a set of electrical devices for providing fast-acting reactive power on high-voltage electric power transmission, electricity transmission networks. SVCs are part of the flexible AC transmission system (FACTS) device family, regulating voltage, power factor, harmonics and stabilizing the system. A static VAR compensator has no significant moving parts (other than internal switchgear). Prior to the invention of the SVC, power factor compensation was the preserve of large rotating machines such as synchronous condensers or switched capacitor banks. The SVC is an automated impedance matching device, designed to bring the system closer to unity power factor. SVCs are used in two main situations: * Connected to the power system, to regulate the transmission voltage ("transmission SVC") * Connected near large industrial loads, to improve power quality ("industrial SVC") In transmission applications, the SVC is used to regulate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Performance Tuning
Performance tuning is the improvement of system Computer performance, performance. Typically in computer systems, the motivation for such activity is called a performance problem, which can be either real or anticipated. Most systems will respond to increased Load (computing), load with some degree of decreasing performance. A system's ability to accept higher load is called scalability, and modifying a system to handle a higher load is synonymous to performance tuning. Systematic tuning follows these steps: # Assess the problem and establish numeric values that categorize acceptable behavior. # Measure the performance of the system before modification. # Identify the part of the system that is critical for improving the performance. This is called the bottleneck (software), bottleneck. # Modify that part of the system to remove the bottleneck. # Measure the performance of the system after modification. # If the modification makes the performance better, adopt it. If the modificatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AC Power
In an electric circuit, instantaneous power is the time rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductors and capacitors may result in periodic reversals of the direction of energy flow. Its SI unit is the watt. The portion of instantaneous power that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as instantaneous active power, and its time average is known as active power or real power. The portion of instantaneous power that results in no net transfer of energy but instead oscillates between the source and load in each cycle due to stored energy is known as instantaneous reactive power, and its amplitude is the absolute value of reactive power. Active, reactive, apparent, and complex power in sinusoidal steady-state For a simple alternating current (AC) circuit in steady-state; consisting of a source and a Linear circuit, linear T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Transmission
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. Efficient long-distance transmission of electric power requires high voltages. This reduces the losses produced by strong currents. Transmission lines use either alternating current (AC) or direct current (DC). The voltage level is changed with transformers. The voltage is stepped up for transmission, then reduced for local distribution. A wide area synchronous grid, known as an ''interconnection'' in North America, directly connects generators delivering AC power with the same relati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Voltage
High voltage electricity refers to electrical potential large enough to cause injury or damage. In certain industries, ''high voltage'' refers to voltage above a certain threshold. Equipment and conductors that carry high voltage warrant special safety requirements and procedures. High voltage is used in electrical power distribution, in cathode-ray tubes, to generate X-rays and particle beams, to produce electrical arcs, for ignition, in photomultiplier tubes, and in high-power amplifier vacuum tubes, as well as other industrial, military and scientific applications. Definition The numerical definition of depends on context. Two factors considered in classifying a voltage as high voltage are the possibility of causing a spark in air, and the danger of electric shock by contact or proximity. The International Electrotechnical Commission and its national counterparts ( IET, IEEE, VDE, etc.) define ''high voltage'' as above 1000 V for alternating current, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controlled Shunt Reactor
In electrical engineering, a magnetically-controlled shunt reactor (MCSR, CSR) represents electrotechnical equipment purposed for compensation of reactive power and stabilization of voltage level in high voltage (HV) transmission network, electric networks rated for voltage classes 36 – 750 kV. MCSR is a shunt (electrical), shunt-type static device with smooth regulation by means of inductive reactance. History In 2002, The first Controlled Shunt Reactor (CSR) was developed by Bharat Heavy Electricals Limited. The first such device was commissioned at Power Grid's 400 kV Itarsi substation in Madhya Pradesh. Purpose Magnetically-controlled shunt reactors are intended for automatic control over reactive power and stabilization of voltage levels; these ensure the following: * Elimination of daily and seasonal voltage variations in the power network; * Improvement of electric power quality; * Optimization and automation of power network operating modes; * Reduction of electric p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volt-ampere
The volt-ampere ( SI symbol: VA, sometimes V⋅A or V A) is the unit of measurement for apparent power in an electrical circuit. It is the product of the root mean square voltage (in volts) and the root mean square current (in amperes). Volt-amperes are usually used for analyzing alternating current (AC) circuits. In direct current (DC) circuits, this product is equal to the real power, measured in watts. The volt-ampere is dimensionally equivalent to the watt: in SI units, 1 V⋅A = 1 W. VA rating is most used for generators and transformers, and other power handling equipment, where loads may be reactive (inductive or capacitive). Formulation For a simple electrical circuit running on direct current, the electrical current and voltage are constant. In that case, the real power (''P'', measured in watts) is the product of the current (''I'', measured in amperes) and the voltage from one side of the circuit to the other (''V'', measured in volts): ... [...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] |
Edith Clarke
Edith Clarke (February 10, 1883 – October 29, 1959) was an American engineer and academic. She was the first woman to be professionally employed as an electrical engineer in the United States and the first female professor of electrical engineering in the country. She was the first woman to deliver a paper at the American Institute of Electrical Engineers; the first female engineer whose professional standing was recognized by Tau Beta Pi, the oldest engineering honor society and the second oldest collegiate honor society in the United States; and the first woman named as a Fellow of the American Institute of Electrical Engineers. She specialized in electrical power system analysis and wrote ''Circuit Analysis of A-C Power Systems''. Early life and education One of nine children, Edith Clarke was born to lawyer John Ridgely Clarke and Susan Dorsey Owings on February 10, 1883, in Ellicott City, Maryland. After being orphaned at age 12, she was raised by an older sister. She us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
