Transmission power lines (commonly four wires) are connected from pole to pole, some places in parallel (to the earth) and some places in perpendicular (to the earth). Why ?
Answers
A transmission tower or power tower (alternatively electricity pylon or variations) 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 sub-transmission 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 15 to 55 m (49 to 180 ft),[1] though the tallest are the 380 m (1,247 ft) towers of 2,656 m (8,714 ft) spanning between the islands Jintang and Cezi. The longest span of any hydroelectric crossing ever built belongs to the powerline crossing of Ameralik fjord with a length of 5,376 m (17,638 ft). In addition to steel, other materials may be used, including concrete and wood.
There are four major categories of transmission towers:[1] suspension, terminal, tension, and transposition. Some transmission towers combine these basic functions. Transmission towers and their overhead power lines are often considered to be a form of visual pollution. Methods to reduce the visual effect include undergrounding.