Transmission tower
tall structure used to support an overhead power line
A transmission tower (also known as an electricity pylon, hydro tower, or pylon) is a tall structure used to support an overhead power line. It is usually a lattice or tubular tower made of steel. In electrical grids, transmission towers carry high-voltage transmission lines that transport electric power from generating stations to electrical substations; while utility poles are used to support lower-voltage, electricity contactor relays, sub-station, sub-transmission lines or distribution lines that transport electricity from substations to electricity installed capacity to end customers.
There are four categories of transmission towers: (i) the suspension tower, (ii) the dead-end tower, (iii) the termination tower, and (iv) the transposition tower. The heights of transmission towers typically range from 15 to 55 m (49 to 180 ft), although when longer spans are needed, such as for crossing water, taller towers are sometimes used.
Terminology
Transmission tower is the term for the structure used in the industry in the United States and some other English-speaking countries. 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. In Canada, the term hydro tower is used, because hydroelectricity is the primary source of electricity for the country.
History
The first sketch for a transmission tower was made by the Pittsburgh Bridge Company in 1894 for a two-circuit three-phase AC power line from Niagara to Buffalo. They chose to place the power line on wooden poles.
“Transmission tower” enters the record as tall structure used to support an overhead power line. Crown Archives preserves that source wording while asking what Transmission, tower and tall can confirm, complicate or overturn.
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This entry incorporates text from “Transmission tower” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.