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Encyclopedia > Power outage
Tree limbs create a short circuit in electrical lines during a storm that spawned two tornadoes.

A power outage (also known as power cut, power failure or power loss) is the loss of the electricity supply to an area. Image File history File linksMetadata Download high-resolution version (1200x800, 815 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Short circuit Power outage Wikipedia:Picture peer review User:Rklawton/Galleries Wikipedia:Picture peer review/Short... Image File history File linksMetadata Download high-resolution version (1200x800, 815 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Short circuit Power outage Wikipedia:Picture peer review User:Rklawton/Galleries Wikipedia:Picture peer review/Short... Transmission lines in Lund, Sweden Electric power, often known as power or electricity, involves the production and delivery of electrical energy in sufficient quantities to operate domestic appliances, office equipment, industrial machinery and provide sufficient energy for both domestic and commercial lighting, heating, cooking and industrial processes. ...


The reasons for a power failure can for instance be a defect in a power station, damage to a power line or other part of the distribution system, a short circuit, or the overloading of electricity mains. While the developed countries enjoy a highly uninterrupted supply of electric power all the time, many developing countries have acute power shortage as compared to the demand. For other uses, see Power station (disambiguation). ... For alternate meanings see Short circuit (disambiguation) A short circuit (sometimes known as simply a short) is a fault whereby electricity moves through a circuit in an unintended path, usually due to a connection forming where none was expected. ...


Some developing countries and newly-industrialized countries have several hours of daily power-cuts in almost all cities and villages because the increase in demand for electricity exceeds the increase in electric power generation. Wealthier people in these countries may use a power-inverter (rechargeable batteries) or a diesel/petrol-run electric generator at their homes during the power-cut. The use of standby generators is common in industrial and IT hubs. A developing country is a country with low average income compared to the world average. ... The category of newly-industrialized country (NIC) is a socioeconomic classification applied to several countries around the world by political scientists and economists. ... Generator redirects here. ... Emergency power systems are a type of device, which may include lighting, generators and other apparatus, to provide backup resources in a crisis or when regular systems fail. ... Information and communication technology spending in 2005 Information technology (IT), as defined by the Information Technology Association of America (ITAA), is the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware. ...


A power outage may take one of three forms:

Blackout
where power is lost completely. "Load shedding" or a rolling blackout is a common term for a controlled way of rotating available generation capacity between various districts or customers, thus avoiding wide area total blackouts.
Brownout
where the voltage level is below the normal minimum level specified for the system. Systems supplied with three-phase electric power also suffer brownouts if one or more phases are absent, at reduced voltage, or incorrectly phased. Such malfunctions are particularly damaging to electric motors. Some brownouts, called voltage reductions, are made intentionally to prevent a full power outage.
Dropout
where the loss of power is only momentary (milliseconds to seconds).

Power failures are particularly critical for hospitals, since many life-critical medical devices and tasks require power. For this reason hospitals, just like many enterprises (notably colocation facilities and other datacenters), have emergency power generators which are typically powered by diesel fuel and configured to start automatically, as soon as a power failure occurs. In most third world countries, power cuts go unnoticed by most citizens of upscale means, as maintaining an uninterruptible power supply is often considered an essential facility of a home. Rolling blackout refers to an intentionally-engineered electrical power outage, caused by insufficient available resources to meet prevailing demand for electricity. ... Three-phase power transformer which is the sole transfer point for electricity to a suburban shopping mall in Canada. ... For other kinds of motors, see motor. ... For the town in the Republic of Ireland, see Hospital, County Limerick. ... ‹ The template below (Expand) is being considered for deletion. ... A colocation centre (colo) or carrier hotel is a type of data center where multiple telecommunications network or service providers, such as telcos or ISPs, site their connections to one anothers networks (points of presence). ... A data center is a facility used for housing a large amount of electronic equipment, typically computers and communications equipment. ... ... For the Jamaican reggae band, see Third World (band). ... An uninterruptible power supply (UPS), also known as an uninterruptible power source or a battery backup is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a separate source when utility power is not available. ...


Power outage may also be the cause of sanitary sewer overflow, a condition of discharging raw sewage into the environment. Other life-critical systems such as telecommunications are also required to have emergency power. Telephone exchange rooms usually have arrays of lead-acid batteries for backup and also a socket for connecting a diesel generator during extended periods of outage. Decentralized wet weather overflow event Sanitary sewer overflow (SSO} is a condition whereby untreated sewage is discharged into the environment, escaping wastewater treatment. ... Telecommunication involves the transmission of signals over a distance for the purpose of communication. ... Lead-acid batteries are the most commonly used rechargeable batteries today. ... This article is about the fuel. ...


Power outages may also be caused by terrorism (attacking power plants or electricity pylons) in developing countries. The Shining Path movement was the first to copy this tactic from Mao Zedong. Terrorist redirects here. ... Pylon redirects here. ... The Communist Party of Peru (Spanish: Partido Comunista del Perú), more commonly known as the Shining Path (Sendero Luminoso), is a Maoist guerrilla organization in Peru that launched the internal conflict in Peru in 1980. ... Mao redirects here. ...

Contents

Protecting the power system from outages

In power supply networks, the power generation and the electrical load (demand) must be very close to equal every second to avoid overloading of network components, which can severely damage them. In order to prevent this, parts of the system will automatically disconnect themselves from the rest of the system, or shut themselves down to avoid damage. This is analogous to the role of relays and fuses in households. 200 A Industrial fuse. ...


Under certain conditions, a network component shutting down can cause current fluctuations in neighboring segments of the network, though this is unlikely, leading to a cascading failure of a larger section of the network. This may range from a building, to a block, to an entire city, to the entire electrical grid. A cascading failure is failure in a system of interconnected parts, where the service provided depends on the operation of a preceding part, and the failure of a preceding part can trigger the failure of successive parts. ... Electric power transmission is the second process in the delivery of electricity to consumers. ...


Modern power systems are designed to be resistant to this sort of cascading failure, but it may be unavoidable (see below). Moreover, since there is no short-term economic benefit to preventing rare large-scale failures, some observers have expressed concern that there is a tendency to erode the resilience of the network over time, which is only corrected after a major failure occurs. It has been claimed that reducing the likelihood of small outages only increases the likelihood of larger ones. In that case, the short-term economic benefit of keeping the individual customer happy increases the likelihood of large-scale blackouts.


Restoring power after a wide-area outage

Restoring power after a wide-area outage can be difficult, as power stations need to be brought back on-line. Normally, this is done with the help of power from the rest of the grid. In the absence of grid power, a so-called black start needs to be performed to bootstrap the power grid into operation. Restoring power after a wide-area power outage can be difficult, as power stations need to be brought back on-line. ... There are very few or no other articles that link to this one. ...

See also: Uninterruptible power supply

An uninterruptible power supply (UPS), also known as an uninterruptible power source or a battery backup is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a separate source when utility power is not available. ...

Blackout unavoidabillity and electric sustainability

It has recently been argued on the basis of historical data[1] and computer modelling[2] that power grids are self-organized critical systems. These systems exhibit unavoidable[3] disturbances of all sizes, up to the size of the entire system, and attempts to reduce the probability of small disturbances only increase the probability of large ones[4]. This has immediate policy implications[1]. The following are the relevant quotations from the sources cited: Transmission towers Transmission lines in Lund, Sweden Electric power transmission, or more accurately Electrical energy transmission, is the second process in the delivery of electricity to consumers. ... The theory of self-organized criticality (SOC) claims that whenever a self-organizing dynamical system is open or dissipative, it exhibits critical (scale-invariant) behaviour similar to that displayed by static systems undergoing a second-order phase transition. ...

As expected from studies of general self-organised critical systems, ... apparently sensible efforts to reduce the risk of smaller blackouts can sometimes increase the risk of large blackouts [4]
...the NERC blackout data suggests that the North American power system has been operating near criticality. ...It would be better to analyze this tradeoff between catastrophic blackout risk and loading instead of just waiting for the effects to manifest themselves in the North American power system! [1]
[The models'] PDF of the blackouts size has the same power dependence that have been found from the analysis of NERC data for the North American power grid over a period of 15 years. [2]
First and perhaps most striking is the intrinsic unavoidability of cascading events in such a system when driven near its operational limits. [3]

A complex network-based model to control large cascading failures (blackouts) using local information only was proposed in A. E. Motter, Cascade control and defense in complex networks, Phys. Rev. Lett. 93, 098701 (2004). The North American Electric Reliability Corporation (NERC) is a nonprofit corporation based in Princeton, NJ which was formed March 28, 2006. ... A cascading failure is failure in a system of interconnected parts, where the service provided depends on the operation of a preceding part, and the failure of a preceding part can trigger the failure of successive parts. ... Adilson E. Motter, born January 1, 1974, is a Brazilian-born American-based scientist working at Northwestern University. ...


See also

Energy Portal

Image File history File links Portal. ... This is a list of famous wide-scale power outages The Northeast Blackout of 1965 on November 9, 1965. ... Brittle Power: Energy Strategy for National Security is a 1982 book by Amory B. Lovins and L. Hunter Lovins, prepared originally as a Pentagon study, and re-released in 2001 following the September 11 attacks. ... In physics and engineering, including mechanical and electrical engineering, energy efficiency is a dimensionless number, with a value between 0 and 1 or, when multiplied by 100, is given as a percentage. ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... Rolling blackout refers to an intentionally-engineered electrical power outage, caused by insufficient available resources to meet prevailing demand for electricity. ... An uninterruptible power supply (UPS), also known as an uninterruptible power source or a battery backup is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a separate source when utility power is not available. ... Vehicle to Grid (V2G) technology is a bi-directional grid interface for gridable Electric vehicles such as Battery Electric Vehicles (BEV) and Plug-in Hybrid Electric Vehicles (PHEV). ...

References

  1. ^ a b c http://www.computer.org/proceedings/hicss/1435/volume2/14350063abs.htm
  2. ^ a b http://ffden-2.phys.uaf.edu/HICSS2002-paper2.pdf
  3. ^ a b http://eceserv0.ece.wisc.edu/~dobson/PAPERS/carrerasHICSS00.pdf
  4. ^ a b http://eetd.lbl.gov/certs/pdf/Dobson_4.pdf

External links


  Results from FactBites:
 
Power outage - Wikipedia, the free encyclopedia (758 words)
A power outage is the loss of the electricity supply to an area.
The reasons for a power failure can for instance be a defect in a power station, damage to a power line or other part of the distribution system, a short circuit, or the overloading of electricity mains.
In most third world countries, power cuts are left unnoticed by most citizens of moderate means, as maintaining an uninterruptible power supply is often not considered an essential facility of a home.
2003 North America blackout - Wikipedia, the free encyclopedia (5867 words)
In areas where power remained off after nightfall, the Milky Way and orbiting artificial satellites became visible to the naked eye in metropolitan areas where they cannot ordinarily be seen due to the effects of light pollution.
The operators of the power system control center are responsible for ensuring that they balance the supply of power, the loads (customers demanding that power), and the transmission line capacity, so that their system was in a state where no single fault can cause it to fail.
They also have power flow modeling tools which let them analyze what is currently happening on their network, predict whether any parts of it may be overloaded and predict what the worst possible failure left is so that they can change the power generation, load or transmission to prevent a failure if that accident happens.
  More results at FactBites »

 
 

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