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Dartford Cable Tunnel
The Dartford Cable Tunnel is a 2.4 km utility tunnel beneath the Thames, upstream of the Dartford Crossing. With a diameter of ~, it carries a 400 kV National Grid electrical transmission cable. It is accessible by foot as a crossing of the Thames, but by authorised personnel only. It was built in 2003–04 at a cost of £11 million (equivalent to £ million in ). See also * 400 kV Thames Crossing * * |
National Grid Plc
National Grid plc is a British multinational electricity and gas utility company headquartered in London, England. Its principal activities are in the United Kingdom, where it owns and operates electricity and natural gas transmission networks, and in the Northeastern United States, where as well as operating transmission networks, the company produces and supplies electricity and gas, providing both to customers in New York and Massachusetts. National Grid plc is one of the largest investor-owned utility companies in the world; it has a primary listing on the London Stock Exchange where it is a constituent of the FTSE 100 Index, and a secondary listing in the form of its American depositary receipts on the New York Stock Exchange. History Background (CEGB before 1990) Before 1990, both the generation and transmission activities in England and Wales were under the responsibility of the Central Electricity Generating Board (CEGB). The present electricity market in the Unite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utility Tunnel
A utility tunnel, utility corridor, or utilidor is a passage built underground or above ground to carry utility lines such as electricity, steam, water supply pipes, and sewer pipes. Communications utilities like fiber optics, cable television, and telephone cables are also sometimes carried. One may also be referred to as a services tunnel, services trench, services vault, or cable vault. Smaller cable containment is often referred to as a cable duct or underground conduit. Direct-buried cable is a major alternative to ducts or tunnels. Usage Utility tunnels are common in very cold climates where direct burial below the frost line is not feasible (such as in Alaska, where the frost line is often more than below the surface, which is frozen year round). They are also built in places where the water table is too high to bury water and sewer mains, and where utility poles would be too unsightly or pose a danger (like in earthquake prone Tokyo). Tunnels are also built to avoid t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Thames
The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, second-longest in the United Kingdom, after the River Severn. The river rises at Thames Head in Gloucestershire, and flows into the North Sea near Tilbury, Essex and Gravesend, Kent, via the Thames Estuary. From the west it flows through Oxford (where it is sometimes called the Isis), Reading, Berkshire, Reading, Henley-on-Thames and Windsor, Berkshire, Windsor. The Thames also drains the whole of Greater London. In August 2022, the source of the river moved five miles to beyond Somerford Keynes due to the heatwave in July 2022. The lower reaches of the river are called the Tideway, derived from its long tidal reach up to Teddington Lock. Its tidal section includes most of its London stretch and has a rise and fall of . From Oxford to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dartford Crossing
The Dartford-Thurrock River Crossing, commonly known as the Dartford Crossing and until 1991 the Dartford Tunnel, is a major road crossing of the River Thames in England, carrying the A282 road between Dartford in Kent in the south and Thurrock in Essex in the north. It consists of two bored tunnels and the cable-stayed Queen Elizabeth II Bridge. The only fixed road crossing of the Thames east of Greater London, it is the busiest estuarial crossing in the United Kingdom, with an average daily use of over 130,000 vehicles. It opened in stages: the west tunnel in 1963, the east tunnel in 1980 and the bridge in 1991. The crossing, although not officially designated a motorway, is considered part of the M25 motorway's route, using the tunnels northbound and bridge southbound. Described as one of the most important road crossings in Britain, it suffers from heavy traffic and congestion. The crossing's development started in the late 1930s, but was interrupted due to the Second W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for the diameter of a sphere. In more modern usage, the length d of a diameter is also called the diameter. In this sense one speaks of diameter rather than diameter (which refers to the line segment itself), because all diameters of a circle or sphere have the same length, this being twice the radius r. :d = 2r \qquad\text\qquad r = \frac. For a convex shape in the plane, the diameter is defined to be the largest distance that can be formed between two opposite parallel lines tangent to its boundary, and the is often defined to be the smallest such distance. Both quantities can be calculated efficiently using rotating calipers. For a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilovolt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Definition One volt is defined as the electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points. Equivalently, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it. It can be expressed in terms of SI base units ( m, kg, s, and A) as : \text = \frac = \frac = \frac. It can also be expressed as amperes times ohms (current times resistance, Ohm's law), webers per second (magnetic flux per time), watts per ampere (power per current), or joules per coulomb (energy per charge), which is also equivalent to electronvolts per elementary charge: : \text = \text\Omega = \frac = \ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Grid (UK)
In the electricity sector in the United Kingdom, the National Grid is the high-voltage electric power transmission network serving Great Britain, connecting power stations and major substations and ensuring that electricity generated anywhere on it can be used to satisfy demand elsewhere. The network covers the great majority of Great Britain and several of the surrounding islands. It does not cover Northern Ireland, which is part of a single electricity market with the Republic of Ireland. The GB grid is connected as a wide area synchronous grid nominally running at 50 hertz. There are also undersea interconnections to other grids in the Isle of Man, Northern Ireland, the Republic of Ireland, France, Belgium, the Netherlands and Norway. On the breakup of the Central Electricity Generating Board in 1990, the ownership and operation of the National Grid in England and Wales passed to National Grid Company plc, later to become National Grid Transco, and now National Grid plc. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
400 KV Thames Crossing
The 400 kV Thames Crossing is an overhead power line crossing of the River Thames, between Botany Marshes in Swanscombe, Kent, and West Thurrock, Essex, England. Its towers are the tallest electricity pylons in the UK. The present crossing was built in 1965, and comprises two 190-metre (623 feet) tall lattice towers each side of the Thames. Some suggest that the choice of this height was deliberate, being just taller than the BT Tower in London. The span is , the minimum height of the conductors over the river is 76 metres (249 feet). Each tower has three crossarms and carries two circuits of 400 kV three-phase AC. 400 kV power lines also cross the Thames at the Thames Cable Tunnel, the Dartford Cable Tunnel, and the London Power Tunnels. 132 kV Thames Crossing There was at one time an earlier 132 kV crossing nearby, with towers 148.4 metres tall. Linking Dagenham and Crossness, it was built between 1927 and 1932 and was part of the Belvedere-Crowlands 132/33/25 kV doubl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thames Cable Tunnel
The Thames Cable Tunnel, also known as the Tilbury – Gravesend Cable Tunnel, is a tunnel carrying high-voltage electrical transmission lines beneath the lower River Thames between Tilbury and Gravesend. It remains the furthest tunnel downstream on the Thames. Completed in 1970 at a cost of around £3 million (equivalent to £ million in ) by the Central Electricity Generating Board, the tunnel carries 400 kV transmission cables between substations at Tilbury and Kingsnorth as part of the National Grid. The tunnel is approximately deep, and was one of the first tunnels in the UK to be lined with pre-cast concrete segments rather than cast iron. A tunnel was chosen due to the high costs of building an overhead transmission line at this point in the river. See also * 400 kV Thames Crossing * Dartford Cable Tunnel The Dartford Cable Tunnel is a 2.4 km utility tunnel beneath the Thames, upstream of the Dartford Crossing. With a diameter of ~, it carries a 400 kV ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utility Vault
A utility vault is an underground room providing access to subterranean public utility equipment, such as valves for water or natural gas pipes, or switchgear for electrical or telecommunications equipment. A vault is often accessible directly from a street, sidewalk or other outdoor space, thereby distinct from a basement of a building.City of New York, New York. ''2014 Construction Codes.'' Building Code, Chapter 32"Section 3201.8. Definitions.""Vault: Any space below the surface of a street, that is covered over, except those openings that are used exclusively as places for descending, by means of steps, to the cellar or basement of any building." Accessed 2018-04-09. Utility vaults are commonly constructed out of reinforced concrete boxes, poured concrete or brick. Small ones are usually entered through a manhole or grate on the topside and closed up by a manhole cover. Such vaults are considered confined spaces and can be hazardous to enter. Large utility vaults are similar t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossings Of The River Thames
The River Thames is the second-longest river in the United Kingdom, passes through the capital city, and has many crossings. Counting every channel – such as by its islands linked to only one bank – it is crossed by over 300 bridges. If taking cuts – excavated channels – to be measurements of river, its course west of Tilbury, traversing has 27 tunnels, six public ferries, one cable car link, and one ford. From end to end a channel of the Thames can be seen, mostly its main flow, which is passed over by 138 bridges. These are listed here with 2 former bridges and a seasonal festival bridge. Over 162 other bridges link to such places as typical or man-made islands or across an array of corollary and lesser side channels (backwaters), particularly in and around Oxford and the non-village channel of Ashton Keynes — these are not listed. The river's lower estuary is shallow – but wide – and has no crossing east of Tilbury, the ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnels Underneath The River Thames
The table below lists many of the tunnels under the River Thames in and near London, which, thanks largely to its underlying bed of clay, is one of the most tunnelled cities in the world. The tunnels are used for road vehicles, pedestrians, Tube and railway lines and utilities. Several tunnels are over a century old: the original Thames Tunnel was the world's first underwater tunnel. List of tunnels Other tunnels The figure and list above leaves out a tunnel to the site of the old Ferranti power station on the east side of the mouth of Deptford Creek. There is also a tunnel between Cottons centre and the old Billingsgate Fish Market near to London Bridge. Citibank used it for cabling at one point; it was large enough for a person to walk through. The Silvertown Tunnel is a new Thames river crossing proposed to supplement the existing Blackwall Tunnel, which will join the Greenwich Peninsula with West Silvertown. The Thames Tideway Tunnel, due for completion in 2025, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
