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Undergrounding
In civil engineering, undergrounding is the replacement of overhead cables providing electrical power or telecommunications, with underground cables. It helps in wildfire prevention and in making the power lines less susceptible to outages during high winds, thunderstorms or heavy snow or ice storms. An added benefit of undergrounding is the aesthetic quality of the landscape without the powerlines. Undergrounding can increase the capital cost of electric power transmission and distribution but may decrease operating costs over the lifetime of the cables. History Early undergrounding had a basis in the detonation of mining explosives and in undersea telegraph cables. Electric cables were used in Russia to detonate mining explosives in 1812, and to carry telegraph signals across the English Channel in 1850. With the spread of early electrical power systems, undergrounding began to increase as well. Thomas Edison used underground DC “street pipes” in his early distributio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Power 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 (HVAC) or direct current (HVDC). 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 rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electricity Pylon
A transmission tower, also known as an electricity pylon or simply a pylon in British English and as a hydro tower in Canadian English, is a tall structure, usually a steel lattice tower, used to support an overhead power line. In electrical grids, they are generally used to carry high-voltage transmission lines that transport bulk electric power from generating stations to electrical substations; utility poles are used to support lower-voltage subtransmission and distribution lines that transport power from substations to electric customers. They come in a wide variety of shapes and sizes. Typical height ranges from , though the tallest are the towers of a span between the islands Jintang and Cezi in China's Zhejiang province. The longest span of any hydroelectric crossing ever built belongs to the powerline crossing of Ameralik fjord with a length of . In addition to steel, other materials may be used, including concrete and wood. There are four major categories of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct-buried Cable
Direct-buried cable (DBC) is a kind of communications or transmissions electrical cable which is especially designed to be buried under the ground without any other cover, sheath, or duct to protect it. Most direct-buried cable is built to specific tolerances to heat, moisture, conductivity, and soil acidity. Unlike standard telecommunications and power cables, which have only a thin layer of insulation and a waterproof outer cover, DBC consists of multiple layers of heavy metallic-banded sheathing, reinforced by heavy rubber covers, shock absorbing gel, wrapped thread-fortified waterproof tape, and stiffened by a heavy metal core. DBC is preferable in some areas since it is more resistant to being the focus of lightning discharges. Communications Most cable of this kind is coaxial or bundled fiber-optic cable. In the 20th century much of it was filled cable. Direct-buried cable is cheaper and easier to lay than other kinds of cable that require protection from the earth. Ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Line
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more uninsulated electrical cables (commonly multiples of three for three-phase power) suspended by towers or poles. Since most of the insulation is provided by the surrounding air, overhead power lines are generally the least costly method of power transmission for large quantities of electric energy. Construction Towers for support of the lines are made of wood either 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 reinforced with steel or composite materials such as carbon and glass fiber), though some copper wires are used in medium-voltage distribution and low-voltage connections to customer premises. A major goal of overhead power line d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactive Power
Reactive may refer to: *Generally, capable of having a reaction (other) *An adjective abbreviation denoting a bowling ball coverstock made of reactive resin *Reactivity (chemistry) *Reactive mind *Reactive programming See also *Reactance (other) Reactance may refer to: * Electrical reactance In electrical circuits, reactance is the opposition presented to alternating current by inductance or capacitance. Greater reactance gives smaller current for the same applied voltage. Reactance is ... * Reactivity (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2011 Christchurch Earthquake
A major earthquake occurred in Christchurch on Tuesday 22 February 2011 at 12:51 p.m. local time (23:51 UTC, 21 February). The () earthquake struck the entire of the Canterbury region in the South Island, centred south-east of the central business district. It caused widespread damage across Christchurch, killing 185 people, in New Zealand's fifth-deadliest disaster. Christchurch's central city and eastern suburbs were badly affected, with damage to buildings and infrastructure already weakened by the magnitude 7.1 Canterbury earthquake of 4 September 2010 and its aftershocks. Significant liquefaction affected the eastern suburbs, producing around 400,000 tonnes of silt. The earthquake was felt across the South Island and parts of the lower and central North Island. While the initial quake only lasted for approximately 10 seconds, the damage was severe because of the location and shallowness of the earthquake's focus in relation to Christchurch as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquefaction
In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially. As an example of the latter, a "major commercial application of liquefaction is the liquefaction of air to allow separation of the constituents, such as oxygen, nitrogen, and the noble gases." Another is the conversion of solid coal into a liquid form usable as a substitute for liquid fuels. Geology In geology, soil liquefaction refers to the process by which water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid, often in an earthquake. Soil liquefaction was blamed for building collapses in the city of Palu, Indonesia in October 2018. In a related phenomenon, liquefaction of bulk materials in cargo ships may cause a dangerous shift in the load. Physics and chemistry In physics and chemistry, the phase transiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utility Trench In Bwy @ 42 St Jeh
As a topic of economics, utility is used to model worth or Value (economics), value. Its usage has evolved significantly over time. The term was introduced initially as a measure of pleasure or happiness as part of the theory of utilitarianism by moral philosophers such as Jeremy Bentham and John Stuart Mill. The term has been adapted and reapplied within neoclassical economics, which dominates modern economic theory, as a utility function that represents a single consumer's preference ordering over a choice set but is not comparable across consumers. This concept of utility is personal and based on choice rather than on pleasure received, and so is specified more rigorously than the original concept but makes it less useful (and controversial) for ethical decisions. Utility function Consider a set of alternatives among which a person can make a preference ordering. The utility obtained from these alternatives is an unknown function of the utilities obtained from each alternat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Of Gas And Electricity Markets
, type = Non-ministerial government department , nativename = , nativename_a = , nativename_r = , logo = Ofgem logo.svg , logo_width = 124px , logo_caption = , seal = , seal_width = , seal_caption = , picture = , picture_width = , picture_caption = , formed = , preceding1 = Office of Electricity Regulation , preceding2 = Office of Gas Supply , dissolved = , superseding = , jurisdiction = Great Britain , headquarters = 10 South Colonnade, Canary Wharf, London, , region_code = GB , coordinates = , employees = 1,187 , budget = For 2015–2016 Parliament approved through the Main Estimate a gross resource budget of £89.5 million , minister1_name = Grant Shapps , minister1_pfo = Secretary of State for Business, Energy and Industrial Strategy , chief1_name = Jonathan Brearley , chief1_position = Chief Executive , chief2_name = , chief2_position = , chief3_name = , chief3_position = , chief4_name = , chief4_position = , chief5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Fields
An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by (stationary or moving) electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical counterpart to the quantized electromagnetic field tensor in quantum electrodynamics (a quantum field theory). The electromagnetic field propagates at the speed of light (in fact, this field can be identified ''as'' light) and interacts with charges and currents. Its quantum counterpart is one of the four fundamental forces of nature (the others are gravitation, weak interaction and strong interaction.) The field can be viewed as the combination of an electric field and a magnetic field. The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. The way in which charges and currents interact with the electromagnetic field is described ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Areas Of Outstanding Natural Beauty
An Area of Outstanding Natural Beauty (AONB; , AHNE) is an area of countryside in England, Wales, and Northern Ireland, that has been designated for conservation due to its significant landscape value. Areas are designated in recognition of their national importance by the relevant public body: Natural England, Natural Resources Wales, and the Northern Ireland Environment Agency respectively. In place of AONB, Scotland uses the similar national scenic area (NSA) designation. Areas of Outstanding Natural Beauty enjoy levels of protection from development similar to those of UK national parks, but unlike national parks the responsible bodies do not have their own planning powers. They also differ from national parks in their more limited opportunities for extensive outdoor recreation. History The idea for what would eventually become the AONB designation was first put forward by John Dower in his 1945 ''Report to the Government on National Parks in England and Wales''. Dower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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