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There are four categories of transmission towers: (i) the [[suspension tower]], (ii) the [[Dead-end tower#Termination pylon|dead-end terminal]] tower, (iii) the [[Dead-end tower|tension tower]], and (iv) the [[transposition tower]].<ref name="IFC" />
There are four categories of transmission towers: (i) the [[suspension tower]], (ii) the [[Dead-end tower#Termination pylon|dead-end terminal]] tower, (iii) the [[Dead-end tower|tension tower]], and (iv) the [[transposition tower]].<ref name="IFC" />
The heights of transmission towers typically range from {{cvt|15|to|55|m}},<ref name=IFC>{{cite web |url= http://www.ifc.org/wps/wcm/connect/66b56e00488657eeb36af36a6515bb18/Final%2B-%2BElectric%2BTransmission%2Band%2BDistribution.pdf?MOD=AJPERES&id=1323162154847|title=Environmental, Health, and Safety Guidelines for Electric Power Transmission and Distribution |format=PDF |publisher=International Finance Corporation |date=2007-04-30 |page=21 |access-date=2013-09-15}}</ref> although when longer spans are needed, such as for crossing water, taller towers are sometimes used. More transmission towers are needed to [[Climate change mitigation|mitigate climate change]], so in the 2020s transmission towers became politically important.<ref>{{Cite news |title=The Case for an Environmentalism that Builds |newspaper=The Economist |url=https://www.economist.com/leaders/2023/04/05/the-case-for-an-environmentalism-that-builds |access-date=2023-10-03 |issn=0013-0613}}</ref><ref>{{cite news | url=https://www.bbc.co.uk/news/uk-scotland-scotland-business-66336599 | title=The looming battle over pylons for green energy | work=BBC News | date=31 July 2023 }}</ref>
The heights of transmission towers typically range from {{cvt|15|to|55|m}},<ref name=IFC>{{cite web |url= http://www.ifc.org/wps/wcm/connect/66b56e00488657eeb36af36a6515bb18/Final%2B-%2BElectric%2BTransmission%2Band%2BDistribution.pdf?MOD=AJPERES&id=1323162154847|title=Environmental, Health, and Safety Guidelines for Electric Power Transmission and Distribution |format=PDF |publisher=International Finance Corporation |date=2007-04-30 |page=21 |access-date=2013-09-15}}</ref> although when longer spans are needed, such as for crossing water, taller towers are sometimes used. More transmission towers are needed to [[Climate change mitigation|mitigate climate change]], and as a result, transmission towers became politically important in the 2020s.<ref>{{Cite news |title=The Case for an Environmentalism that Builds |newspaper=The Economist |url=https://www.economist.com/leaders/2023/04/05/the-case-for-an-environmentalism-that-builds |access-date=2023-10-03 |issn=0013-0613}}</ref><ref>{{cite news | url=https://www.bbc.co.uk/news/uk-scotland-scotland-business-66336599 | title=The looming battle over pylons for green energy | work=BBC News | date=31 July 2023 }}</ref>


== Terminology ==
== Terminology ==
Line 49: Line 49:
== Tower designs ==
== Tower designs ==


Transmission towers must withstand various external forces, including wind, ice, and seismic activity, while supporting the weight of heavy conductors.
===The Art and Science of Transmission Tower Design===
Transmission towers must withstand various external forces, including wind, ice, and seismic activity, while supporting the weight of heavy conductors. Engineers meticulously calculate loads, analyze stresses, and select appropriate materials to ensure that towers remain stable and resilient under diverse conditions.


[[File:Electricity Wire Annotated.jpg|thumb|A close up of the wires attached to the pylon, showing the various parts annotated.]]
[[File:Electricity Wire Annotated.jpg|thumb|A close up of the wires attached to the pylon, showing the various parts annotated.]]
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==== Four circuits ====
==== Four circuits ====
Christmas-tree-shaped towers for 4 or even 6 circuits are common in Germany and have 3 cross arms where the highest arm has each one cable, the second has two cables and the third has three cables on each side. The cables on the third arm usually carry circuits for lower high voltage.
Christmas-tree-shaped towers for 4 or even 6 circuits are common in Germany and have 3 cross arms where the highest arm has each one cable, the second has two cables and the third has three cables on each side. The cables on the third arm usually carry circuits for lower high voltage.

====Branch pylons====
[[File:Kreuzungsmast.jpg|thumb|Branch pylon with a triangular shape]]
[[File:Zabrze cross pylon.jpg|thumb|Pylon with additional crossbars for a possible branch]]
Special designed pylons are necessary to introduce branching lines, e.g. to connect nearby substations.


=== Support structures ===
=== Support structures ===
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|Línea de Transmisión Carapongo – Carabayllo || 2011 || Peru || Lima || 170.5 m ||Crossing of Rimac River in a 1055 metres long span
|Línea de Transmisión Carapongo – Carabayllo || 2011 || Peru || Lima || 170.5 m ||Crossing of Rimac River in a 1055 metres long span
|-
|-
|Doel Schelde Powerline Crossing 1<ref>{{cite web |url=https://www.emporis.com/buildings/1227186/river-tower-of-doel-schelde-powerline-crossing-antwerp-belgium |url-status=dead |archive-url=https://web.archive.org/web/20200701130904/https://www.emporis.com/buildings/1227186/river-tower-of-doel-schelde-powerline-crossing-antwerp-belgium |archive-date=2020-07-01 |title=River Tower of Doel Schelde Powerline Crossing, Antwerp {{!}} 1227186 {{!}} EMPORIS}}</ref> || 1974 ||Belgium || Antwerp || 170 m || Group of 2 towers with 1 pylon situated in the middle of Schelde River
|Doel Schelde Powerline Crossing 1<ref>{{cite web |url=https://www.emporis.com/buildings/1227186/river-tower-of-doel-schelde-powerline-crossing-antwerp-belgium |url-status=usurped |archive-url=https://web.archive.org/web/20200701130904/https://www.emporis.com/buildings/1227186/river-tower-of-doel-schelde-powerline-crossing-antwerp-belgium |archive-date=2020-07-01 |title=River Tower of Doel Schelde Powerline Crossing, Antwerp {{!}} 1227186 {{!}} EMPORIS}}</ref> || 1974 ||Belgium || Antwerp || 170 m || Group of 2 towers with 1 pylon situated in the middle of Schelde River
|-
|-
|Sunshine Mississippi Powerline Crossing ||1967||United States ||St. Gabriel, Louisiana ||164.6 m || Tallest electricity pylons in the [[United States]] [http://skyscraperpage.com/cities/?buildingID=127169], [http://skyscraperpage.com/cities/?buildingID=127170]
|Sunshine Mississippi Powerline Crossing ||1967||United States ||St. Gabriel, Louisiana ||164.6 m || Tallest electricity pylons in the [[United States]] [http://skyscraperpage.com/cities/?buildingID=127169], [http://skyscraperpage.com/cities/?buildingID=127170]
Line 465: Line 469:
|-
|-
| Source<ref>{{cite web |url=http://electric-art.eu/ |title = Electric Art::High-tension towers into artworks}}</ref> || 2004 || France || Amnéville les Thermes || 34&nbsp;m / 28&nbsp;m || 4 pylons forming an artwork
| Source<ref>{{cite web |url=http://electric-art.eu/ |title = Electric Art::High-tension towers into artworks}}</ref> || 2004 || France || Amnéville les Thermes || 34&nbsp;m / 28&nbsp;m || 4 pylons forming an artwork
|-
| Tower 9108 || 1983 || Germany || [[Fulda]] || 20.4&nbsp;m || Base situated in a storage building, looks like roof-mounted
|-
|-
| Western Tower of Overhead Line of [[Straussee Ferry|Ostrich Lake Ferry]] || 1915 || Germany || Strausberg || 9.7&nbsp;m || carries together with its counterpart on the other bank of Ostrich Lake the longest span (length: 370 metres) of an overhead wire for feeding electric power to a vehicle
| Western Tower of Overhead Line of [[Straussee Ferry|Ostrich Lake Ferry]] || 1915 || Germany || Strausberg || 9.7&nbsp;m || carries together with its counterpart on the other bank of Ostrich Lake the longest span (length: 370 metres) of an overhead wire for feeding electric power to a vehicle
Line 491: Line 497:
* [http://myinsulators.com/hungary/index.html Electricity pylons in Hungary]
* [http://myinsulators.com/hungary/index.html Electricity pylons in Hungary]
* [http://www.pylons.org/ Pylon Appreciation Society]
* [http://www.pylons.org/ Pylon Appreciation Society]
* [http://www.gorge.org/pylons Flash Bristow's pylon photo gallery and pylon FAQ]
* [http://www.magnificentviews.tk/ Magnificent Views: Pictures of High Voltage Towers (also offers technical information)]
* [http://en.structurae.de/structures/ftype/index.cfm?id=2018 Structurae database of select notable transmission towers]
* [http://en.structurae.de/structures/ftype/index.cfm?id=2018 Structurae database of select notable transmission towers]
* [http://novoklimov.io.ua/ Pylons in Russia and other areas of former Soviet Union]
* [http://novoklimov.io.ua/ Pylons in Russia and other areas of former Soviet Union]
* [http://skyscraperpage.com/diagrams/?buildingID=121691,120476,112661,112636,105965,104712,51948,51949,51951,51952,46242,46241,58412,61025,58848,2723,41642,58846,58850,61328,61478,61479,80783,80784,80785,80786,60896,61042,61043,61046,61045,60894,60895,60897,72917,72918,60899,60901,46204,46205,60769,60770,61316,61315,45670,45671,58756,71997,57806,57807,57805,57808,79106,79107,45608,73316,64003,64004,64005,64006,27742,27743,63205,63206,54043,82328,78330,83046,83047,82930,82931,83246,83318,83319,83385,83685,83720,83730,85554,85555,87090,87091,88832,89131,89132,89133,89134,89757,89758,63192,63193,91001,91156,91157,94005,94006,80782,83301,98288,98289,5974,12958,523,7229,20416,21979,14603,2292,38957,15462,5845,27478,17487,29045,6358,34277,38987,36356,60961,39390,15483,14537,18661,32819,17334,3888,7847,15347,17031,15463,72915,72916,17662,28318,41996,2058,58101,107804,108075,99564,99565,110194,110195,6757,51961,115262,115263,118215,118217,121707,12841,122012,127169,127170,128609,128610,133292,133288,138305,138307,138308,139787,141175,141177,142760,142761,142762,142810,142811,142812,143024,143022,143142,143146,143148,143149,143150,143151,143153,143155,143156,143157,143158,143188,143211,143220,143210,143280,143281,143282,143283,143289,143290,143319,143320,143339,143348,143349,143350,143436,143437,143438,143439,143440,143441,143443,143444,143445,143446,144756,134272,134273,146882,146883,148992,149488,151387,151388 Collection] of some electricity pylons on [http://www.skyscraperpage.com/ Skyscraperpage.com]
* [https://www.bbc.co.uk/news/uk-32234656 Meet the 'pylon spotters' – BBC News]
* [https://www.bbc.co.uk/news/uk-32234656 Meet the 'pylon spotters' – BBC News]
* [https://www.youtube.com/watch?v=a9zdz780l-U Documentary on erecting towers in New Zealand] on YouTube
* [https://www.youtube.com/watch?v=a9zdz780l-U Documentary on erecting towers in New Zealand] on YouTube
*[https://tower-ist.com/transmission-tower-design/ transmission tower design]


{{Electricity generation}}
{{Electricity generation}}

Latest revision as of 23:16, 26 October 2024

Transmission tower
Transmission tower in Dnipro, Ukraine
TypeStructure, lattice tower and overhead power line
First production 20th century

A transmission tower (also electricity pylon, hydro tower, or pylon) is a tall structure, usually a lattice tower made of steel that is used to support an overhead power line. In electrical grids, transmission towers carry high-voltage transmission lines that transport bulk electric power from generating stations to electrical substations, from which electricity is delivered to end consumers; moreover, utility poles are used to support lower-voltage sub-transmission and distribution lines that transport electricity from substations to electricity customers.

There are four categories of transmission towers: (i) the suspension tower, (ii) the dead-end terminal tower, (iii) the tension tower, and (iv) the transposition tower.[1] The heights of transmission towers typically range from 15 to 55 m (49 to 180 ft),[1] although when longer spans are needed, such as for crossing water, taller towers are sometimes used. More transmission towers are needed to mitigate climate change, and as a result, transmission towers became politically important in the 2020s.[2][3]

Terminology

[edit]

Transmission tower is the name for the structure used in the industry in the United States and some other English-speaking countries.[4] In Europe and the U.K., the terms electricity pylon and pylon derive from the basic shape of the structure, an obelisk with a tapered top.[5] In Canada, the term hydrotower is used, because hydroelectricity is the principal source of electricity for the country.[6][7]

High voltage AC transmission towers

[edit]
Transmission tower in Toronto, ON
Single-circuit three-phase transmission line
Transmission towers on a hill field

Three-phase electric power systems are used for high voltage (66- or 69-kV and above) and extra-high voltage (110- or 115-kV and above; most often 138- or 230-kV and above in contemporary systems) AC transmission lines. In some European countries, e.g. Germany, Spain or Czech Republic, smaller lattice towers are used for medium voltage (above 10 kV) transmission lines too. The towers must be designed to carry three (or multiples of three) conductors. The towers are usually steel lattices or trusses (wooden structures are used in Australia, Canada, Germany, and Scandinavia in some cases) and the insulators are either glass or porcelain discs or composite insulators using silicone rubber or EPDM rubber material assembled in strings or long rods whose lengths are dependent on the line voltage and environmental conditions.

Typically, one or two ground wires, also called "guard" wires, are placed on top to intercept lightning and harmlessly divert it to ground.

Towers for high- and extra-high voltage are usually designed to carry two or more electric circuits.[citation needed] If a line is constructed using towers designed to carry several circuits, it is not necessary to install all the circuits at the time of construction. Indeed, for economic reasons, some transmission lines are designed for three (or four) circuits, but only two (or three) circuits are initially installed.

Some high voltage circuits are often erected on the same tower as 110 kV lines. Paralleling circuits of 380 kV, 220 kV and 110 kV-lines on the same towers is common. Sometimes, especially with 110 kV circuits, a parallel circuit carries traction lines for railway electrification.

High voltage DC transmission towers

[edit]
HVDC distance tower near the Nelson River Bipole

High-voltage direct current (HVDC) transmission lines are either monopolar or bipolar systems. With bipolar systems, a conductor arrangement with one conductor on each side of the tower is used. On some schemes, the ground conductor is used as electrode line or ground return. In this case, it had to be installed with insulators equipped with surge arrestors on the pylons in order to prevent electrochemical corrosion of the pylons. For single-pole HVDC transmission with ground return, towers with only one conductor can be used. In many cases, however, the towers are designed for later conversion to a two-pole system. In these cases, often conductors on both sides of the tower are installed for mechanical reasons. Until the second pole is needed, it is either used as electrode line or joined in parallel with the pole in use. In the latter case, the line from the converter station to the earthing (grounding) electrode is built as underground cable, as overhead line on a separate right of way or by using the ground conductors.

Electrode line towers are used in some HVDC schemes to carry the power line from the converter station to the grounding electrode. They are similar to structures used for lines with voltages of 10–30 kV, but normally carry only one or two conductors.

AC transmission towers may be converted to full or mixed HVDC use, to increase power transmission levels at a lower cost than building a new transmission line.[8][9]

Railway traction line towers

[edit]

Towers used for single-phase AC railway traction lines are similar in construction to those towers used for 110 kV three-phase lines. Steel tube or concrete poles are also often used for these lines. However, railway traction current systems are two-pole AC systems, so traction lines are designed for two conductors (or multiples of two, usually four, eight, or twelve). These are usually arranged on one level, whereby each circuit occupies one half of the cross arm. For four traction circuits, the arrangement of the conductors is in two levels and for six electric circuits, the arrangement of the conductors is in three levels.

Tower designs

[edit]

Transmission towers must withstand various external forces, including wind, ice, and seismic activity, while supporting the weight of heavy conductors.

A close up of the wires attached to the pylon, showing the various parts annotated.

Shape

[edit]
Typical T-shaped 110 kV tower from the former GDR.

Different shapes of transmission towers are typical for different countries. The shape also depends on voltage and number of circuits.

One circuit

[edit]
Guyed "Delta" transmission tower (a combination of guyed "V" and "Y") in Nevada.

Delta pylons are the most common design for single circuit lines, because of their stability. They have a V-shaped body with a horizontal arm on the top, which forms an inverted delta. Larger Delta towers usually use two guard cables.

Portal pylons are widely used in the USA, Ireland, Scandinavia and Canada. They stand on two legs with one cross arm, which gives them a H-shape. Up to 110 kV they often were made from wood, but higher voltage lines use steel pylons.

Smaller single circuit pylons may have two small cross arms on one side and one on the other.

Two circuits

[edit]

One level pylons only have one cross arm carrying 3 cables on each side. Sometimes they have an additional cross arm for the protection cables. They are frequently used close to airports due to their reduced height.

Danube pylons or Donaumasten got their name from a line built in 1927 next to the Danube river. They are the most common design in central European countries like Germany or Poland. They have two cross arms, the upper arm carries one and the lower arm carries two cables on each side. Sometimes they have an additional cross arm for the protection cables.

Ton shaped towers are the most common design, they have 3 horizontal levels with one cable very close to the pylon on each side. In the United Kingdom the second level is often (but not always) wider than the other ones while in the United States all cross arms have the same width.

T-pylons
[edit]

In 2021 the first T-pylon, a new tubular T-shaped design, was installed in United Kingdom for a new power line to Hinkley Point C nuclear power station, carrying two high voltage 400 kV power lines.[10][11] The design features electricity cables strung below a cross-arm atop a single pole which reduces the visual impact on the environment compared to lattice pylons. These 36 T-pylons were the first major UK redesign since 1927, designed by Danish company Bystrup, winner of a 2011 competition from more than 250 entries held by the Royal Institute of British Architects and Her Majesty's Government.[12]

T-pylon
End of line of T-pylons
T-pylon
T-pylons 3D design
Y-pylons
[edit]

Y-pylons are a newer concept for electrical transmission towers. They usually have a guy-wire or support beam to help support the "Y" shape in the tower.[13][14]

Y-pylon with support beam

Four circuits

[edit]

Christmas-tree-shaped towers for 4 or even 6 circuits are common in Germany and have 3 cross arms where the highest arm has each one cable, the second has two cables and the third has three cables on each side. The cables on the third arm usually carry circuits for lower high voltage.

Branch pylons

[edit]
Branch pylon with a triangular shape
Pylon with additional crossbars for a possible branch

Special designed pylons are necessary to introduce branching lines, e.g. to connect nearby substations.

Support structures

[edit]

Towers may be self-supporting and capable of resisting all forces due to conductor loads, unbalanced conductors, wind and ice in any direction. Such towers often have approximately square bases and usually four points of contact with the ground.

A semi-flexible tower is designed so that it can use overhead grounding wires to transfer mechanical load to adjacent structures, if a phase conductor breaks and the structure is subject to unbalanced loads. This type is useful at extra-high voltages, where phase conductors are bundled (two or more wires per phase). It is unlikely for all of them to break at once, barring a catastrophic crash or storm.

A guyed mast has a very small footprint and relies on guy wires in tension to support the structure and any unbalanced tension load from the conductors. A guyed tower can be made in a V shape, which saves weight and cost.[15]

Materials

[edit]
Steel tube tower next to older lattice tower near Wagga Wagga, Australia

Tubular steel

[edit]

Poles made of tubular steel generally are assembled at the factory and placed on the right-of-way afterward. Because of its durability and ease of manufacturing and installation, many utilities in recent years prefer the use of monopolar steel or concrete towers over lattice steel for new power lines and tower replacements. [citation needed]

Tubular transmission tower
Tubular transmission tower
Tubular transmission tower near Galesville, Wisconsin

In Germany steel tube pylons are also established predominantly for medium voltage lines, in addition, for high voltage transmission lines or two electric circuits for operating voltages by up to 110 kV. Steel tube pylons are also frequently used for 380 kV lines in France, and for 500 kV lines in the United States.

Lattice

[edit]

A lattice tower is a framework construction made of steel or aluminium sections. Lattice towers are used for power lines of all voltages, and are the most common type for high-voltage transmission lines. Lattice towers are usually made of galvanized steel. Aluminium is used for reduced weight, such as in mountainous areas where structures are placed by helicopter. Aluminium is also used in environments that would be corrosive to steel. The extra material cost of aluminium towers will be offset by lower installation cost. Design of aluminium lattice towers is similar to that for steel, but must take into account aluminium's lower Young's modulus.

A lattice tower is usually assembled at the location where it is to be erected. This makes very tall towers possible, up to 100 m (328 ft) (and in special cases even higher, as in the Elbe crossing 1 and Elbe crossing 2). Assembly of lattice steel towers can be done using a crane. Lattice steel towers are generally made of angle-profiled steel beams (L-beam or T-beams). For very tall towers, trusses are often used.

Wood

[edit]

Wood is a material which is limited in use in high-voltage transmission. Because of the limited height of available trees, the maximum height of wooden pylons is limited to approximately 30 m (98 ft). Wood is rarely used for lattice framework. Instead, they are used to build multi-pole structures, such as H-frame and K-frame structures. The voltages they carry are also limited, such as in other regions, where wood structures only carry voltages up to approximately 30 kV.

In countries such as Canada or the United States, wooden towers carry voltages up to 345 kV; these can be less costly than steel structures and take advantage of the surge voltage insulating properties of wood.[15] As of 2012, 345 kV lines on wood towers are still in use in the US and some are still being constructed on this technology.[16][17] Wood can also be used for temporary structures while constructing a permanent replacement.

Concrete

[edit]
A reinforced concrete pole in Germany

Concrete pylons are used in Germany normally only for lines with operating voltages below 30 kV. In exceptional cases, concrete pylons are used also for 110 kV lines, as well as for the public grid or for the railway traction current grid. Concrete poles for medium-voltage are also used in Canada and the United States.

In Switzerland, concrete pylons with heights of up to 59.5 metres (world's tallest pylon of prefabricated concrete at Littau) are used for 380 kV overhead lines. In Argentina and some other south american countries, many overhead power lines, except the ultra-high voltage grid, were placed on tubular concrete pylons. Also in former soviet countries, concrete pylons are common, though with crossarms made of steel.[18]

Concrete pylons, which are not prefabricated, are also used for constructions taller than 60 metres. One example is a 61.3 m (201 ft) tall pylon of a 380 kV powerline near Reuter West Power Plant in Berlin.[citation needed] In China some pylons for lines crossing rivers were built of concrete. The tallest of these pylons belong to the Yangtze Powerline crossing at Nanjing with a height of 257 m (843 ft).

Special designs

[edit]

Sometimes (in particular on steel lattice towers for the highest voltage levels) transmitting plants are installed, and antennas mounted on the top above or below the overhead ground wire. Usually these installations are for mobile phone services or the operating radio of the power supply firm, but occasionally also for other radio services, like directional radio. Thus transmitting antennas for low-power FM radio and television transmitters were already installed on pylons. On the Elbe Crossing 1 tower, there is a radar facility belonging to the Hamburg water and navigation office.

For crossing broad valleys, a large distance between the conductors must be maintained to avoid short-circuits caused by conductor cables colliding during storms. To achieve this, sometimes a separate mast or tower is used for each conductor. For crossing wide rivers and straits with flat coastlines, very tall towers must be built due to the necessity of a large height clearance for navigation. Such towers and the conductors they carry must be equipped with flight safety lamps and reflectors.

Two well-known wide river crossings are the Elbe Crossing 1 and Elbe Crossing 2. The latter has the tallest overhead line masts in Europe, at 227 m (745 ft) tall. In Spain, the overhead line crossing pylons in the Spanish bay of Cádiz have a particularly interesting construction. The main crossing towers are 158 m (518 ft) tall with one crossarm atop a frustum framework construction. The longest overhead line spans are the crossing of the Norwegian Sognefjord Span (4,597 m (15,082 ft) between two masts) and the Ameralik Span in Greenland (5,376 m (17,638 ft)). In Germany, the overhead line of the EnBW AG crossing of the Eyachtal has the longest span in the country at 1,444 m (4,738 ft).

In order to drop overhead lines into steep, deep valleys, inclined towers are occasionally used. These are utilized at the Hoover Dam, located in the United States, to descend the cliff walls of the Black Canyon of the Colorado. In Switzerland, a pylon inclined around 20 degrees to the vertical is located near Sargans, St. Gallens. Highly sloping masts are used on two 380 kV pylons in Switzerland, the top 32 meters of one of them being bent by 18 degrees to the vertical.

Power station chimneys are sometimes equipped with crossbars for fixing conductors of the outgoing lines. Because of possible problems with corrosion by flue gases, such constructions are very rare.

There exist also a variety of pylons and powerline poles mounted on buildings. The most common forms are small rooftop poles used in some countries like Germany for the realization of overhead 400/230 volt grids for the power supply of homes [1].

However, there are also roof-mounted support structures for high-voltage. Some thermal power plants in Poland like Połaniec Power Station and in the former Soviet Union like Lukoml Power Station use portal pylons on the roof of the power station building for the high voltage line from the machine transformer to the switchyard. Also other industrial buildings may have a rooftop powerline support structure. One can find such a device at a steel work in Dnipro, Ukraine at 48°28'57"N 34°58'43"E and at a steel work in Freital, Germany at 50°59'53"N 13°38'26"E. In the United States such device may be more common as in other countries [2], [3] There are also real rooftop high voltage towers on industry buildings as at a steel plant in Piombino, Italy [4] and on a roof on an industrial building at Cherepovets, Russia at 59°8'52"N 37°51'55"E.
Until 2015, on a residential highrise building in Dazhou, China at 31°11'28"N 107°30'43"E a powerline tower stood.

Beside this, it is also possible that the lower parts of an electricity pylon stand in a building. Such a structure a person, who cannot have a view of the interior of the building, cannot distinguish from a real rooftop pylon. A structure of this type is Tower 9108 of a 110 kV high-voltage traction power line in Fulda [5], File:Mast9108-Fundament.jpg.

A new type of pylon, called Wintrack pylons, will be used in the Netherlands starting in 2010. The pylons were designed as a minimalist structure by Dutch architects Zwarts and Jansma. The use of physical laws for the design made a reduction of the magnetic field possible. Also, the visual impact on the surrounding landscape is reduced.[19]

Two clown-shaped pylons appear in Hungary, on both sides of the M5 motorway, near Újhartyán.[20]

The Pro Football Hall of Fame in Canton, Ohio, U.S., and American Electric Power paired to conceive, design, and install goal post-shaped towers located on both sides of Interstate 77 near the hall as part of a power infrastructure upgrade.[21]

The Mickey pylon is a Mickey Mouse shaped transmission tower on the side of Interstate 4, near Walt Disney World in Orlando, FL. Bog Fox is a design pylon in Estonia south of Risti at 58° 59′ 33.44″ N, 24° 3′ 33.19″ E.

In Russia several pylons designed as artwork were built [6]

Assembly

[edit]

Before transmission towers are even erected, prototype towers are tested at tower testing stations. There are a variety of ways they can then be assembled and erected:

  • They can be assembled horizontally on the ground and erected by push-pull cable. This method is rarely used because of the large assembly area needed.
  • They can be assembled vertically (in their final upright position). Very tall towers, such as the Yangtze River Crossing, were assembled in this way.
  • A jin-pole crane can be used to assemble lattice towers.[22] This is also used for utility poles.
  • Helicopters can serve as aerial cranes for their assembly in areas with limited accessibility. Towers can also be assembled elsewhere and flown to their place on the transmission right-of-way.[23] Helicopters may also be used for transporting disassembled towers for scrapping.[24]

Markers

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The International Civil Aviation Organization issues recommendations on markers for towers and the conductors suspended between them. Certain jurisdictions will make these recommendations mandatory, for example that certain power lines must have overhead wire markers placed at intervals, and that warning lights be placed on any sufficiently high towers,[25] this is particularly true of transmission towers which are in close vicinity to airports.

Electricity pylons often have an identification tag marked with the name of the line (either the terminal points of the line or the internal designation of the power company) and the tower number. This makes identifying the location of a fault to the power company that owns the tower easier.

Transmission towers, much like other steel lattice towers including broadcasting or cellphone towers, are marked with signs which discourage public access due to the danger of the high voltage. Often this is accomplished with a sign warning of the high voltage. At other times, the entire access point to the transmission corridor is marked with a sign. Sign warning of the high voltage may also state the name of the company who built the structures, and acquired and designated lands where the transmission structures stand and line segments or right of way.

Tower functions

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Tower structures can be classified by the way in which they support the line conductors.[26] Suspension structures support the conductor vertically using suspension insulators. Strain structures resist net tension in the conductors and the conductors attach to the structure through strain insulators. Dead-end structures support the full weight of the conductor and also all the tension in it, and also use strain insulators.

Structures are classified as tangent suspension, angle suspension, tangent strain, angle strain, tangent dead-end and angle dead-end.[15] Where the conductors are in a straight line, a tangent tower is used. Angle towers are used where a line must change direction.

Cross arms and conductor arrangement

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Generally three conductors are required per AC 3-phase circuit, although single-phase and DC circuits are also carried on towers. Conductors may be arranged in one plane, or by use of several cross-arms may be arranged in a roughly symmetrical, triangulated pattern to balance the impedances of all three phases. If more than one circuit is required to be carried and the width of the line right-of-way does not permit multiple towers to be used, two or three circuits can be carried on the same tower using several levels of cross-arms. Often multiple circuits are the same voltage, but mixed voltages can be found on some structures.

Other features

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Insulators

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A high voltage insulator in the UK. Arcing horns are also in place.

Insulators electrically isolate the live side of the transmission cables from the tower structure and earth. They are either glass or porcelain discs or composite insulators using silicone rubber or EPDM rubber material. They are assembled in strings or long rods whose lengths are dependent on the line voltage and environmental conditions. By using disks the shortest surface electrical path between the ends is maximised which reduces the chance of a leakage in moist conditions.

Stockbridge dampers

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Stockbridge damper bolted to line close to the point of attachment to the tower. It prevents mechanical vibration building up in the line.

Stockbridge dampers are added to the transmission lines a meter or two from the tower. They consist of a short length of cable clamped in place parallel to the line itself and weighted at each end. The size and dimensions are carefully designed to damp any buildup of mechanical oscillation of the lines that could be induced by mechanical vibrations most likely caused by wind. Without them it's possible for a standing wave to become established that grows in magnitude and destroys the line or the tower.

Arcing horns

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Arcing horns. Designs may vary.

Arcing horns are sometimes added to the ends of the insulators in areas where voltage surges may occur. These may be caused by either lightning strikes or in switching operations. They protect power line insulators from damage due to arcing. They can be seen as rounded metal pipework at either end of the insulator and provide a path to earth in extreme circumstances without damaging the insulator.

Physical security

[edit]

Towers will have a level of physical security to prevent members of the public or climbing animals from ascending them. This may take the form of a security fence or climbing baffles added to the supporting legs. Some countries require that lattice steel towers be equipped with a barbed wire barrier approximately 3 m (9.8 ft) above ground in order to deter unauthorized climbing. Such barriers can often be found on towers close to roads or other areas with easy public access, even where there is not a legal requirement. In the United Kingdom, all such towers are fitted with barbed wire.

Other features

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Some electricity pylons, especially for voltages above 100 kV, carry transmission antennas. In most cases these are cellphone antennas and antennas for radio relay links adjoined with them, but it is also possible that antennas of radio relay systems of power companies or antenna for small broadcasting transmitters in the VHF-/UHF-range are installed. The northern tower of Elbekreuzung 1 carries in a height of 30 metres a radar station for monitoring ship traffic on Elbe river on its structure. The Tower 93 of Facility 4101, a strainer at Hürth south of Cologne, Germany carried from 1977 to 2010 a public observation deck, which was accessible by a staircase.

Notable electricity transmission towers

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The following electricity transmission towers are notable due to their enormous height, unusual design, unusual construction site or their use in artworks. Bold type denotes structure which was at one time the tallest transmission tower(s) in the world.

Tower Year Country Town Pinnacle Remarks
Jintang-Cezi Overhead Powerline Link 2018-2019 China Jintang Island 380 m 2656 metres long span between Jintang and Cezi island
Zhoushan Island Overhead Powerline Tie 2009–2010 China Damao Island 370 m [27] built by State Grid[28]
Jiangyin Yangtze River Crossing 2003 China Jiangyin 346.5 m
Amazonas Crossing of Tucuruí transmission line 2013 Brazil near Almeirim 295 m[29] Tallest electricity pylons in South America
Yangtze River power line crossing of Shanghai-Huainan Powerline 2013 China Gaogouzhen 269.75 m
Nanjing Yangtze River Crossing 1992 China Nanjing 257 m Tallest reinforced concrete pylons in the world
Pylons of Pearl River Crossing 1987 China Pearl River 253 m + 240 m
Orinoco River Crossing 1990 Venezuela Caroní 240 m
Hooghly River Crossing India Diamond Harbour 236 m [7]
Pylons of Messina 1957 Italy Messina 232 m (224 m without basement) Not used as pylons any more
HVDC Yangtze River Crossing Wuhu 2003 China Wuhu 229 m Tallest electricity pylons used for HVDC
Elbe Crossing 2 1976–1978 Germany Stade 227 m Tallest electricity pylons still in use in Europe
Chushi Powerline Crossing 1962 Japan Takehara 226 m Tallest electricity pylons in Japan
Daqi-Channel-Crossing 1997 Japan Takehara 223 m
Overhead line crossing Suez Canal 1998 Egypt 221 m
Huainan Luohe Powerline Crossing 1989 China Huainan 202.5 m Pylons of reinforced concrete
Yangzi River Crossing of HVDC Xianjiaba – Shanghai 2009 China ??? 202 m[30]
Balakovo 500 kV Wolga Crossing, Tower East 1983–1984 Russia Balakovo 197 m Tallest electricity pylon in Russia and ex-USSR
LingBei-Channel-Crossing 1993 Japan Reihoku 195 m
Doel Schelde Powerline Crossing 2 2019 Belgium Antwerp 192 m Second crossing of Schelde River
400 kV Thames Crossing 1965 UK West Thurrock 190 m
Elbe Crossing 1 1958–1962 Germany Stade 189 m
Antwerp Deurganck dok crossing 2000 Belgium Antwerp 178 m Crossing of a container quay
Tracy Saint Lawrence River Powerline Crossing ? Canada Tracy 176 m Tallest electricity pylon in Canada
Línea de Transmisión Carapongo – Carabayllo 2011 Peru Lima 170.5 m Crossing of Rimac River in a 1055 metres long span
Doel Schelde Powerline Crossing 1[31] 1974 Belgium Antwerp 170 m Group of 2 towers with 1 pylon situated in the middle of Schelde River
Sunshine Mississippi Powerline Crossing 1967 United States St. Gabriel, Louisiana 164.6 m Tallest electricity pylons in the United States [8], [9]
Lekkerkerk Crossing 1 1970 Netherlands Lekkerkerk 163 m Tallest crossing in the Netherlands
Bosporus overhead line crossing III 1999 Turkey Istanbul 160 m
Balakovo 500 kV Wolga Crossing, Tower West 1983–1984 Russia Balakovo 159 m
Pylons of Cadiz 1957–1960 Spain Cadiz 158 m
Maracaibo Bay Powerline Crossing ? Venezuela Maracaibo 150 m Towers on caissons
Meredosia-Ipava Illinois River Crossing 2017 United States Beardstown 149.35 m
Aust Severn Powerline Crossing 1959 UK Aust 148.75 m
132 kV Thames Crossing 1932 UK West Thurrock 148.4 m Demolished in 1987
Karmsundet Powerline Crossing ? Norway Karmsundet 143.5 m
Limfjorden Overhead powerline crossing 2 ? Denmark Raerup 141.7 m
Saint Lawrence River HVDC Quebec-New England Overhead Powerline Crossing 1989 Canada Deschambault-Grondines 140 m Dismantled in 1992
Pylons of Voerde 1926 Germany Voerde 138 m
Köhlbrand Powerline Crossing ? Germany Hamburg 138 m
Bremen-Farge Weser Powerline Crossing ? Germany Bremen 135 m
Pylons of Ghesm Crossing 1984 Iran Strait of Ghesm 130 m One pylon standing on a caisson in the sea
Shukhov tower on the Oka River 1929 Russia Dzerzhinsk 128 m Hyperboloid structure, 2 towers, one of them demolished
Tarchomin pylon of Tarchomin-Łomianki Vistula Powerline Crossing ? Poland Tarchomin 127 m
Skolwin pylon of Skolwin-Inoujscie Odra Powerline Crossing ? Poland Skolwin 126 m
Enerhodar Dnipro Powerline Crossing 2 1977 Ukraine Enerhodar 126 m
Inoujscie pylon of Skolwin-Inoujscie Odra Powerline Crossing ? Poland Inoujscie 125 m
Bosporus overhead line crossing II 1983 Turkey Istanbul 124 m
Tista River Crossing 1985 India Jalpaiguri 120 m Pile Foundation
Duisburg-Wanheim Powerline Rhine Crossing ? Germany Duisburg 122 m
Łomianki pylon of Tarchomin-Łomianki Vistula Powerline Crossing ? Poland Łomianki 121 m
Little Belt Overhead powerline crossing 2 ? Denmark Middelfart 125.3 m / 119.2 m
Little Belt Overhead powerline crossing 2 ? Denmark Middelfart 119.5 m / 113.1 m
Pylons of Duisburg-Rheinhausen 1926 Germany Duisburg-Rheinhausen 118.8 m
Bullenhausen Elbe Powerline Crossing ? Germany Bullenhausen 117 m
Lubaniew-Bobrowniki Vistula Powerline Crossing ? Poland Lubaniew/Bobrowniki 117 m
Świerże Górne-Rybaków Vistula Powerline Crossing ? Poland Świerże Górne/Rybaków 116 m
Ostrówek-Tursko Vistula Powerline Crossing ? Poland Ostrówek/Tursko 115 m
Bosporus overhead line crossing I 1957 Turkey Istanbul 113 m
Riga Hydroelectric Power Plant Crossing Pylon 1974 Latvia Salaspils 112 m
Bremen-Industriehafen Weser Powerline Crossing ? Germany Bremen 111 m Two parallel running powerlines, one used for a single phase AC powerline of Deutsche Bahn AG
Probostwo Dolne pylon of Nowy Bógpomóz-Probostwo Dolne Vistula Powerline Crossing ? Poland Nowy Bógpomóz/Probostwo Dolne 111 m
Ameren UE Tower 2009 United States St. Louis, Missouri 111 m Radio tower with crossbars for powerline conductors
Daugava Powerline Crossing 1975 Latvia Riga 110 m
380 kV Ems Overhead Powerline Crossing ? Germany Mark (south of Weener) 110 m
Nowy Bógpomóz pylon of Nowy Bógpomóz-Probostwo Dolne Vistula Powerline Crossing ? Poland Nowy Bógpomóz 109 m
Regów Golab Vistula Powerline Crossing ? Poland Regów/Golab 108 m
Orsoy Rhine Crossing ? Germany Orsoy 105 m
Kerinchi Pylon 1999 Malaysia Kerinchi 103 m Tallest strainer pylon in the world, not part of a powerline crossing of a waterway
Limfjorden Overhead powerline crossing 1 ? Denmark Raerup 101.2 m
Enerhodar Dnipro Powerline Crossing 2 1977 Ukraine Enerhodar 100 m Pylons standing on caissons
Reisholz Rhine Powerline Crossing 1917 Germany Düsseldorf ? Under the legs of the pylon on the east shore of Rhine there runs the rail to nearby Holthausen substation
Sone River Crossing 1983 India Sone Bhadra (Uttar Pradesh) 96 m Pylons standing on Well Foundation
Ghazi pond crossing Tarbela Dam 2017 Pakistan Tarbela Dam 89.5m SPT type tower. First of its type in Pakistan
Al Batinah expressway Road & Rail crossing at Sohar 220 kV Double circuit OETC line 2018 Oman Sohar 89 m Tallest Transmission line tower in Sultanate of Oman
Strelasund Powerline Crossing ? Germany Sundhagen 85 m Pylons standing on caissons
Pylon in the artificial lake of Santa Maria 1959 Switzerland Lake of Santa Maria 75 m Pylon in an artificial lake
Facility 4101, Tower 93 1975 Germany Hürth 74.84 m carried until 2010 an observation deck
Zaporizhzhia Pylon Triple ? Ukraine Zaporizhzhia 74.5 m Two triple pylons used for a powerline crossing from Khortytsia Island to the east shore of Dneipr
Aggersund Crossing of Cross-Skagerrak 1977 Denmark Aggersund 70 m Tallest pylons used for HVDC-transmission in Europe
Eyachtal Span 1992 Germany Höfen 70 m Longest span of Germany (1444 metres)
Leaning pylon of Mingjian ? Taiwan Mingjian ? Earthquake memorial
Carquinez Strait Powerline Crossing 1901 United States Benicia 68 m + 20 m World's first powerline crossing of a larger waterway
Tower 1 of Powerline Reuter-West - Reuter 1987 Germany Berlin 61.3 m Chimney-like strainer however not useable as smokestack, design was chosen in order to fit better into the surrounding industrial area
Pylon 310 of powerline Innertkirchen-Littau-Mettlen 1990 Switzerland Littau 59.5 m Tallest pylon of prefabricated concrete
Huddersfield Narrow Canal Pylon 1967 UK Stalybridge, Greater Manchester 54.6 m Pylon standing over a waterway shipable by small boats
Anlage 2610, Mast 69 ? Germany Bochum 47 m Pylon of 220 kV powerline decorated with balls in Ruhr-Park mall.
Colossus of Eislingen 1980 Germany Eislingen/Fils 47 m Pylon standing over a small river
Pylon 24 of powerline Watari-Kashiwabara ? Japan Uchihara, Ibaraki 45 m Pylon standing over a public road with two lanes
Designer high-voltage pylon Bog Fox 2020 Estonia Risti, Lääne County 45 m The first high-voltage designer pylon in Estonia
Sookurg 2022 Estonia Tartu-Tiksoja, Tähtvere County 44 m designer pylon
Sookureke 2023 Estonia Jõhvi–Tartu–Valga, Mustvee County 40 m designer pylon
Mickey Pylon 1996 US Celebration, Florida 32 m Mickey mouse shaped pylon
Source[32] 2004 France Amnéville les Thermes 34 m / 28 m 4 pylons forming an artwork
Tower 9108 1983 Germany Fulda 20.4 m Base situated in a storage building, looks like roof-mounted
Western Tower of Overhead Line of Ostrich Lake Ferry 1915 Germany Strausberg 9.7 m carries together with its counterpart on the other bank of Ostrich Lake the longest span (length: 370 metres) of an overhead wire for feeding electric power to a vehicle
Eastern Tower of Overhead Line of Ostrich Lake Ferry 2006 Germany Strausberg 9.6 m carries together with its counterpart on the other bank of Ostrich Lake the longest span (length: 370 metres) of an overhead wire for feeding electric power to a vehicle

See also

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References

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  1. ^ a b "Environmental, Health, and Safety Guidelines for Electric Power Transmission and Distribution" (PDF). International Finance Corporation. 2007-04-30. p. 21. Retrieved 2013-09-15.
  2. ^ "The Case for an Environmentalism that Builds". The Economist. ISSN 0013-0613. Retrieved 2023-10-03.
  3. ^ "The looming battle over pylons for green energy". BBC News. 31 July 2023.
  4. ^ "Building a Better Transmission Tower". Department of Energy. Retrieved 2021-07-13.
  5. ^ "Everything you ever wanted to know about electricity pylons | National Grid Group". www.nationalgrid.com. Retrieved 2021-07-13.
  6. ^ Barber, Katherine, ed. (1998). The Canadian Oxford dictionary. Toronto; New York: Oxford University Press. p. 695. ISBN 0-19-541120-X.
  7. ^ Canada, Natural Resources (2017-10-06). "electricity-facts". www.nrcan.gc.ca. Retrieved 2021-07-13.
  8. ^ "Convert from AC to HVDC for higher power transmission". ABB Review: 64–69. 2018. Retrieved 20 June 2020.
  9. ^ Liza Reed; Granger Morgan; Parth Vaishnav; Daniel Erian Armanios (9 July 2019). "Converting existing transmission corridors to HVDC is an overlooked option for increasing transmission capacity". Proceedings of the National Academy of Sciences. 116 (28): 13879–13884. doi:10.1073/pnas.1905656116. PMC 6628792. PMID 31221754.
  10. ^ "World's first T-pylon is installed in UK". Nuclear Engineering International. 26 October 2021. Retrieved 26 October 2021.
  11. ^ "The T-Pylon". BYSTRUP. 2021. Retrieved 16 November 2022.
  12. ^ "UK gets first new-style pylons in a century". BBC News. 2022-03-15. Retrieved 2022-03-21.
  13. ^ "The winner of a new generation of electricity pylons is announced". the Guardian. 2011-10-14. ISSN 0261-3077. Retrieved 2023-08-22.
  14. ^ "[Hot Item] Megatro Y-Shaped Transmission Pylons".
  15. ^ a b c Donald Fink and Wayne Beaty (ed.) Standard Handbook for Electrical Engineers 11th Ed., Mc Graw Hill, 1978, ISBN 0-07-020974-X, pp. 14-102 and 14-103
  16. ^ "Archived copy" (PDF). Archived from the original (PDF) on 2015-02-02. Retrieved 2015-02-02.{{cite web}}: CS1 maint: archived copy as title (link)
  17. ^ Olive Development. "Winterport, Maine". Archived from the original on 2016-03-03. Retrieved 2015-02-02.
  18. ^ The electricity pylon designs of the world - an overview - HoogspanningsNet Forum
  19. ^ "New High Voltage Pylons for the Netherlands". 2009. Retrieved 2010-04-24.
  20. ^ "Clown-shaped High Voltage Pylons in Hungary".47°14′09″N 19°23′27″E / 47.2358442°N 19.3907302°E / 47.2358442; 19.3907302 (Clown-shaped pylon)
  21. ^ Rudell, Tim (2016-06-28). "Drive Through Goal Posts at the Pro Football Hall of Fame". WKSU. Retrieved 2019-07-14.40°49′03″N 81°23′48″W / 40.8174274°N 81.3966678°W / 40.8174274; -81.3966678 (Goal post pylons)
  22. ^ Broadcast Tower Technologies. "Gin Pole Services". Retrieved 2009-10-24.
  23. ^ "Powering Up – Vertical Magazine". verticalmag.com. Archived from the original on 4 October 2015. Retrieved 4 October 2015.
  24. ^ "Helicopter Transport of Transmission Towers". Transmission & Distribution World. 21 May 2018.
  25. ^ "Chapter 6. Visual aids for denoting obstacles" (PDF). Annex 14 Volume I Aerodrome design and operations. International Civil Aviation Organization. 2004-11-25. pp. 6–3, 6–4, 6–5. Retrieved 1 June 2011. 6.2.8 ... spherical ... diameter of not less than 60 cm. ... 6.2.10 ... should be of one colour. ... Figure 6-2 ... 6.3.13
  26. ^ American Society of Civil Engineers Design of latticed steel transmission structures ASCE Standard 10-97, 2000, ISBN 0-7844-0324-4, section C2.3
  27. ^ "World's 2nd tallest power transmission towers in West Bengal". The Economic Times. Nov 26, 2014.
  28. ^ "Zhoushan 500kV network power transmission and transformation project put into operation". Xinhuanet.com. 2019-10-15. Archived from the original on October 15, 2019.
  29. ^ "Concluída primeira torre da linha entre Manaus e Macapá". Archived from the original on 2015-06-12.
  30. ^ CS Tower. "Projects – CS Tower – A leading Steel Tower Manufacturer in the World".
  31. ^ "River Tower of Doel Schelde Powerline Crossing, Antwerp | 1227186 | EMPORIS". Archived from the original on 2020-07-01.{{cite web}}: CS1 maint: unfit URL (link)
  32. ^ "Electric Art::High-tension towers into artworks".
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