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Essential Reliability Services
The power system reliability (sometimes grid reliability) is the probability of a normal operation of the electrical grid at a given time. Reliability indices characterize the ability of the electrical system to supply customers with electricity as needed by measuring the frequency, duration, and scale of supply interruptions. Traditionally two interdependent components of the power system reliability are considered: * power system adequacy, a presence in the system of sufficient amounts of generation and transmission capacity; * power system security (also called operational reliability), an ability of the system to withstand real-time contingencies (adverse events, e.g., an unexpected loss of generation capacity). Ability of the system to limit the scale and duration of a power interruption is called ''resiliency''. The same term is also used to describe the reaction of the system to the truly catastrophic events. Economics Electric grid is an extremely important piece of infr ... [...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] |
Interruptible Load
Firm services, also called uninterruptible services, are services, such as electricity (firm power) and natural gas supplies, that are intended to be available at all times during a period covered by an agreement. Also, the service is not subject to a prior claim from another customer and receives the same priority as any other firm service. Conditional firm service is similar to firm service in that it is reserved and has priority over interruptible service. However, it can have restrictions, such as times when it would be curtailed before firm service but after interruptible service. The cost per unit with this service is called a firm rate or uninterruptible rate. The opposite of firm service is non-firm service, also called interruptible service or as-available service. The cost per unit for this service is called a non-firm rate or interruptible rate. The interruptible load is the portion of a utility's load that comes from customers with interruptible service. Firm service cann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ramping Capability
Inertial response is a property of large Synchronization (alternating current), synchronous generators, which contain large synchronous rotating masses, and which acts to overcome any immediate imbalance between power supply and demand for electric power systems, typically the electrical grid. Due to the ever existing power imbalance between mechanical power supply and electric power demand the rotational frequency of the rotating masses in all synchronous generators in the grid either speed up and thus absorb the extra power in case of an excess power supply, or slow down and provide additional power in case of an excess power demand. This response in case of a synchronous generator is built-in into the design and happens without any external intervention or coordination, providing the automatic generation control and the grid operator with valuable time (few seconds) to Grid balancing, rebalance the system The grid frequency is the combined result of the detailed motions of all in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Support
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 call ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage Control
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 contr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Electric Reliability Corporation
The North American Electric Reliability Corporation (NERC) is a nonprofit corporation based in Atlanta, Georgia, and formed on March 28, 2006, as the successor to the North American Electric Reliability Council (also known as NERC). The original NERC was formed on June 1, 1968, by the electric utility industry to promote the reliability and adequacy of bulk power transmission in the electric utility systems of North America. NERC's mission states that it "is to assure the effective and efficient reduction of risks to the reliability and security of the grid". NERC oversees six regional reliability entities and encompasses all of the interconnected power systems of Canada and the contiguous United States, as well as a portion of the Mexican state of Baja California. NERC's major responsibilities include working with all stakeholders to develop standards for power system operation, monitoring and enforcing compliance with those standards, assessing resource adequacy, and prov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Downtown
''Downtown'' is a term primarily used in American and Canadian English to refer to a city's sometimes commercial, cultural and often the historical, political, and geographic heart. It is often synonymous with its central business district (CBD). It may also be a center for shopping and entertainment. Downtowns typically contain a small percentage of a city's employment but are concentrated in services, including high-end services (office or white-collar jobs). Sometimes, smaller downtowns include lower population densities and nearby lower incomes than suburbs. It is often distinguished as a hub of public transit and culture. History Origins The ''Oxford English Dictionarys first citation for "down town" or "downtown" dates to 1770, in reference to the center of Boston. Some have posited that the term "downtown" was coined in New York City, where it was in use by the 1830s to refer to the original settlement, or town, at the southern tip of the island of Manhattan.Fogels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-1 Security
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] |
Grid Batteries
A battery energy storage system (BESS), battery storage power station, battery energy grid storage (BEGS) or battery grid storage is a type of energy storage technology that uses a group of batteries in the grid to store electrical energy. Battery storage is the fastest responding dispatchable source of power on electric grids, and it is used to stabilise those grids, as battery storage can transition from standby to full power in under a second to deal with grid contingencies. Battery energy storage systems are generally designed to deliver their full rated power for durations ranging from 1 to 4 hours, with emerging technologies extending this to longer durations to meet evolving grid demands. Battery storage can be used for short-term peak power and ancillary services, such as providing operating reserve and frequency control to minimize the chance of power outages. They are often installed at, or close to, other active or disused power stations and may share the same grid c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Photovoltaic
A photovoltaic system, also called a PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and convert sunlight into electricity, a solar inverter to convert the output from direct to alternating current, as well as mounting, cabling, and other electrical accessories to set up a working system. Many utility-scale PV systems use tracking systems that follow the sun's daily path across the sky to generate more electricity than fixed-mounted systems. Photovoltaic systems convert light directly into electricity and are not to be confused with other solar technologies, such as concentrated solar power or solar thermal, used for heating and cooling. A solar array only encompasses the solar panels, the visible part of the PV system, and does not include all the other hardware, often summarized as the balance of system (BOS). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverter-based Resource
An inverter-based resource (IBR) is a source of electricity that is asynchronously connected to the electrical grid via an electronic power converter ("inverter"). The devices in this category, also known as converter interfaced generation (CIG) and power electronic interface source, include the variable renewable energy generators (wind, solar) and battery storage power stations. These devices lack the intrinsic behaviors (like the inertial response of a synchronous generator) and their features are almost entirely defined by the control algorithms, presenting specific challenges to system stability as their penetration increases, for example, a single software fault can affect all devices of a certain type in a contingency (cf. section on Blue Cut fire below). IBRs are sometimes called ''non-synchronous generators''. The design of inverters for the IBR generally follows the IEEE 1547 and NERC PRC-024-2 standards. The term unconventional sources includes IBRs as well as othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous Generator
An alternator (or synchronous generator) is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature.Gordon R. Selmon, ''Magnetoelectric Devices'', John Wiley and Sons, 1966 no ISBN pp. 391-393 Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used. In principle, any AC electrical generator can be called an alternator, but usually, the term refers to small rotating machines driven by automotive and other internal combustion engines. An alternator that uses a permanent magnet for its magnetic field is called a magneto. Alternators in power stations driven by steam turbines are called turbo-alternators. Large 50 or 60 Hz three-phase alternators in power plants generate most of the world's electric power, which is distributed by electric power grids. History Altern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
