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Protection Device
Power system protection is a set of techniques and power grid equipment used to limit the damage caused by an electrical fault and safeguard other components of the grid, like generators and transmission lines. The term is also used for a branch of electrical power engineering that deals with the protection. There is an overlap between the power system protection and power system operations, as the protection equipment, like other switchgear, can be used for operations. The protection devices are used to protect the power systems from faults by detecting the faults and taking ''action'' ("tripping"). P. M. Anderson distinguishes the ''reactionary devices'', like protective relays, that "clear" a fault by isolating it from the rest of system and ''safeguard devices'' that address the source of the hazard (for example, an emergency core cooling system of a nuclear reactor). As a discipline, power system protection mostly deals with the reactionary devices. Protection devices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-voltage Circuit-breaker, White Insulators
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 Electrical conductor, conductors that carry high voltage warrant special Electrical safety standards, 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 arcing, arcs, for ignition, in photomultiplier, 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 (Institution of Engineering an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sectionalizer
In electric power distribution, a recloser, also known as autorecloser or automatic circuit recloser (ACR), is a switchgear designed for use on overhead electricity distribution networks to detect and interrupt transient faults. Reclosers are essentially rated circuit breakers with integrated current and voltage sensors and a protection relay, optimized for use as a protection asset. Commercial reclosers are governed by the IEC 62271-111/IEEE Std C37.60 and IEC 62271-200 standards. The three major classes of operating maximum voltage are 15.5 kV, 27 kV and 38 kV. For overhead electric power distribution networks, up to 80% of faults are transient, such as lightning strike, surges or foreign objects coming into contact with exposed distribution lines. Consequently, these transient faults can be resolved by a simple reclose operation. Reclosers are designed to handle a brief open-close duty cycle, where electrical engineers can optionally configure the number and timing of attem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication Channel
A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for information transfer of, for example, a digital bit stream, from one or several '' senders'' to one or several '' receivers''. A channel has a certain capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second. Communicating an information signal across distance requires some form of pathway or medium. These pathways, called communication channels, use two types of media: Transmission line-based telecommunications cable (e.g. twisted-pair, coaxial, and fiber-optic cable) and broadcast (e.g. microwave, satellite, radio, and infrared). In information theory, a channel refers to a theoretical ''channel model'' with certain error characteristics. In this more general view, a storag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Directional Relay
In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected. The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, overvoltage, reverse power flow, over-frequency, and under-frequency. Microprocessor-based solid-state digital protection relays now emulate the original devices, as well as providing types of protection and supervision impractical with electromechanical relays. Electromechanical relays provide only rudimentary indication of the location and origin of a fault. In many cases a single microprocessor relay provides functions that would take two or more electromechanical devices. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. However, due to their very long life span, tens of thousands of these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit. The opposite of a short circuit is an open circuit, which is an infinite resistance (or very high impedance) between two nodes. Definition A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion. Although usually the result of a fault, there are cases where short circuits are caused intentionally, for example, for the purpose of voltage-sensing crowbar circuit protectors. In circuit analysis, a ''short circuit'' is defined as a connection between two nodes that forces them to be at the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loss Of Load
Loss of load in an electrical grid is a term used to describe the situation when the available generation capacity is less than the system load. Multiple probabilistic reliability indices for the generation systems are using loss of load in their definitions, with the more popular being Loss of Load Probability (LOLP) that characterizes a probability of a loss of load occurring within a year. Loss of load events are calculated before the mitigating actions (purchasing electricity from other systems, load shedding) are taken, so a loss of load does not necessarily cause a blackout. Loss-of-load-based reliability indices Multiple reliability indices for the electrical generation are based on the loss of load being observed/calculated over a long interval (one or multiple years) in relatively small increments (an hour or a day). The total number of increments inside the long interval is designated as N (e.g., for a yearlong interval N=365 if the increment is a day, N=8760 if th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overlapping Zones Of Electrical Protection With Labels
Overlap may refer to: * In set theory, an overlap of elements shared between sets is called an intersection, as in a Venn diagram. * In music theory, overlap is a synonym for reinterpretation of a chord at the boundary of two musical phrases * Overlap (railway signalling), the length of track beyond a stop signal that is proved to be clear of obstructions as a safety margin * Overlap (road), a place where multiple road numbers overlap * Overlap (term rewriting), in mathematics, computer science, and logic, a property of the reduction rules in term rewriting systems * Overlap add, an efficient convolution method using FFT * Overlap coefficient, a similarity measure between sets * Orbital overlap, important concept in quantum mechanics describing a type of orbital interaction that affects bond strength * Overlap, publisher of the light novel series '' Arifureta: From Commonplace to World's Strongest'' Overlapping can refer to: * "Reaching over", term in Schenkerian theory, see Schen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redundancy (engineering)
In engineering and systems theory, redundancy is the intentional duplication of critical components or functions of a system with the goal of increasing reliability of the system, usually in the form of a backup or fail-safe, or to improve actual system performance, such as in the case of GNSS receivers, or multi-threaded computer processing. In many safety-critical systems, such as fly-by-wire and hydraulic systems in aircraft, some parts of the control system may be triplicated, which is formally termed triple modular redundancy (TMR). An error in one component may then be out-voted by the other two. In a triply redundant system, the system has three sub components, all three of which must fail before the system fails. Since each one rarely fails, and the sub components are designed to preclude common failure modes (which can then be modelled as independent failure), the probability of all three failing is calculated to be extraordinarily small; it is often outweighed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Communications
Data communication, including data transmission and data reception, is the transfer of data, signal transmission, transmitted and received over a Point-to-point (telecommunications), point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication using radio spectrum, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal. ''Analog transmission'' is a method of conveying voice, data, image, signal or video information using a continuous signal that varies in amplitude, phase, or some other property in proportion to that of a variable. The messages are either represented by a sequence of pulses by means of a line code (''baseband transmission''), or by a limited set of continuously varying waveforms (''passband transmission''), using a digital modulation method. The passband modulation and cor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Outage
A power outage, also called a blackout, a power failure, a power blackout, a power loss, a power cut, or a power out is the complete loss of the electrical power network supply to an end user. There are many causes of power failures in an electricity network. Examples of these causes include faults at power stations, damage to Electric power transmission, electric transmission lines, Electrical substation, substations or other parts of the electricity distribution, distribution system, a short circuit, Cascading failure#Cascading failure in power transmission, cascading failure, fuse (electrical), fuse or circuit breaker operation. Power failures are particularly critical at sites where the environment and public safety are at risk. Institutions such as hospitals, Sewage Treatment, sewage treatment plants, and mining, mines will usually have backup power sources such as emergency power system, standby generators, which will automatically start up when electrical power is lost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Batteries
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons. When a battery is connected to an external electric load, those negatively charged electrons flow through the circuit and reach the positive terminal, thus causing a redox reaction by attracting positively charged ions, or cations. Thus, higher energy reactants are converted to lower energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary (single-use or "disposable") batteries are used once and discarded, as the electrode m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
