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Load Shedding
Load shedding (LS) is a protective method of emergency power control where, during a large disbalance between supply and demand, the demand (load) is intentionally disconnected ("shed") so that the available electricity supply within a safe timeframe can meet the remaining demand, thereby preventing a cascading collapse of the power grid ''Power Grid'' is the English-language version of the second edition of the multiplayer German-style board game ''Funkenschlag'', designed by Friedemann Friese and first released in 2004. ''Power Grid'' was released by Rio Grande Games. I .... The load shedding is activated when the line frequency becomes too low (under-frequency load shedding, UFLS) or the line voltage is below the specified level (under-voltage load shedding, UVLS). The very act of disconnecting the load introduces yet another disturbance into the grid, so the selection of the bus about to be shed is chosen based on the bus distance from the contingency location as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emergency Power Control
Power system operations is a term used in electricity generation to describe the process of decision-making on the timescale from one day (day-ahead operation) to minutes prior to the power delivery. The term power system control describes actions taken in response to unplanned ''disturbances'' (e.g., changes in demand or equipment failures) in order to provide reliable electric supply of acceptable quality. The corresponding engineering branch is called Power System Operations and Control. Electricity is hard to store, so at any moment the supply (generation) shall be balanced with demand (" grid balancing"). In an electrical grid the task of real-time balancing is performed by a regional-based control center, run by an electric utility in the traditional ( vertically integrated) electricity market. In the restructured North American power transmission grid, these centers belong to '' balancing authorities'' numbered 74 in 2016, the entities responsible for operations are also c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grid Balancing
Grid balancing ensures that electricity consumption matches electricity production of an electrical grid at any moment. Electricity is by its nature difficult to store and has to be available on demand, so the supply shall match the demand very closely at any time despite the continuous variations of both. In a deregulated grid, a transmission system operator is responsible for the balancing (in the US electric system smaller entities, so called balancing authorities, are in charge, overseen by reliability coordinators). In a wide area synchronous grid the short-term balancing is coupled with frequency control: as long as the balance is maintained, the frequency stays constant (at the ''scheduled frequency''), whenever a small mismatch between aggregate demand and aggregate supply occurs, it is restored due to both supply and demand being frequency-sensitive: lower frequency increases the supply, and higher frequency increases the demand. As of the beginning of 2020s, the act ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascading Collapse
A cascading failure is a failure in a system of interconnected parts in which the failure of one or few parts leads to the failure of other parts, growing progressively as a result of positive feedback. This can occur when a single part fails, increasing the probability that other portions of the system fail. Such a failure may happen in many types of systems, including power transmission, computer networking, finance, transportation systems, organisms, the human body, and ecosystems. Cascading failures may occur when one part of the system fails. When this happens, other parts must then compensate for the failed component. This in turn overloads these nodes, causing them to fail as well, prompting additional nodes to fail one after another. In power transmission Cascading failure is common in power grids when one of the elements fails (completely or partially) and shifts its load to nearby elements in the system. Those nearby elements are then pushed beyond their capacity so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Grid
''Power Grid'' is the English-language version of the second edition of the multiplayer German-style board game ''Funkenschlag'', designed by Friedemann Friese and first released in 2004. ''Power Grid'' was released by Rio Grande Games. In the game, each player represents a company which owns power plants and tries to supply electricity to cities. During the game, players bid on power plants and buy resources to provide electricity to the growing number of cities in their network. Background ''Power Grid'' was developed from ''Funkenschlag'', the original game, which had players draw their networks with crayons instead of playing on a fixed map. This and other changes were made when Friedemann Friese reworked the game. The new game is called ''Funkenschlag'' in the German market, but is sold under other names elsewhere. Game play The game comes with a double-sided board with a map of the United States on one side and Germany on the other. Each map has six regions, conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Frequency
The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains electricity by country. During the development of commercial electric power systems in the late-19th and early-20th centuries, many different frequencies (and voltages) had been used. Large investment in equipment at one frequency made standardization a slow process. However, as of the turn of the 21st century, places that now use the 50 Hz frequency tend to use 220–240 V, and those that now use 60 Hz tend to use 100–127 V. Both frequencies coexist today (Japan uses both) with no great technical reason to prefer one over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Voltage (three-phase)
Three-phase electric power (abbreviated 3ϕ) is a common type of alternating current (AC) used in electricity generation, transmission, and distribution. It is a type of polyphase system employing three wires (or four including an optional neutral return wire) and is the most common method used by electrical grids worldwide to transfer power. Three-phase electrical power was developed in the 1880s by several people. In three-phase power, the voltage on each wire is 120 degrees phase shifted relative to each of the other wires. Because it is an AC system, it allows the voltages to be easily stepped up using transformers to high voltage for transmission and back down for distribution, giving high efficiency. A three-wire three-phase circuit is usually more economical than an equivalent two-wire single-phase circuit at the same line-to-ground voltage because it uses less conductor material to transmit a given amount of electrical power. Three-phase power is mainly used directly to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contingency (electrical Grid)
In an electrical grid, contingency is an unexpected failure of a single principal component (e.g., an electrical generator or a power transmission line) that causes the change of the system state large enough to endanger the grid security. Some protective relays are set up in a way that multiple individual components are disconnected due to a single fault, in this case, taking out all the units in a group counts as a single contingency. A scheduled outage (like maintenance) is not a contingency. The choice of term emphasizes the fact that a single fault can cause severe damage to the system so quickly that the operator will not have time to intervene, and therefore a reaction to every single fault has to be defensively pre-built into the system configuration. Some sources use the term interchangeably with "disturbance" and "fault". Contingency analysis The contingency analysis application periodically runs on the computers at the operations centers providing suggestions to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage Collapse
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to move a positive test charge from the first point to the second point. In the International System of Units (SI), the derived unit for voltage is the ''volt'' (''V''). The voltage between points can be caused by the build-up of electric charge (e.g., a capacitor), and from an electromotive force (e.g., electromagnetic induction in a generator). On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect, and the thermoelectric effect. Since it is the difference in electric potential, it is a physical scalar quantity. A voltmeter can be used to measure the voltage between two points in a system. Often a common reference potential such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
