Power transmission poles. Purpose, varieties and their functions. Lattice and multifaceted poles.

An overhead power transmission pole is a special structure designed to hold the wires of overhead power lines, as well as lightning protection cables, at a given distance from each other and from the earth's surface.

Each power transmission pole is designed to perform a specific function assigned to it.

Based on their purpose power transmission poles could be the following:

• Tangent-suspension poles are designed for installation on straight sections of overhead power lines, they perform exclusively the function of supporting wires and cables, and are not designed for loads of pulling wires along the line.
• Anchor – used on straight sections of overhead lines to cross power lines through railways, highways, bridges and small rivers. The design of the anchor poles withstands a significant load of pulling wires and cables.
• Long-span poles are used when power lines cross large obstacles. Long-span poles are the heaviest of all power transmission poles, they can reach heights of up to 300 m, and they are the ones that bear the greatest loads.
• Angle-suspension poles are installed at the turning angles of the overhead line route. At the angle up to 30°, when the load is not so great, tangent-suspension poles are used. If the turning angle is greater, a more rigid structure is needed, and in this case, angle-suspension anchor poles with appropriate wire fastening are used.
• Dead-end structures (poles) are installed at the beginning or at the end of the overhead lines, placed in front of electrical substations on the portals of outdoor switchgear.
• Transposition poles are used to change the order of the wires on the poles.
• Branch poles are used for organizing branches from overhead lines.
• Cross poles are installed at the intersection of overhead lines of two directions.
• Windproof poles are used to enhance mechanical strength.

The history of the development of the overhead power transmission poles has three periods: wood, concrete and metal.

When the need arose for the transmission of electricity over long distances for the first time, it was quite logical that the most affordable material at that time was used for the construction of power lines – the wood. However, very soon its drawbacks became obvious – rotting of wood in the place of contact with the ground, weak durability and vulnerability in front of fires.

They were replaced by more durable concrete poles that are not exposed to fire, corrosion and chemicals, the only and significant drawback of which is their huge weight, that creates difficulties during transportation and installation of the poles. Also, the problem was their disposal after the poles became unusable.

And now, concrete poles are replaced by metal poles which do not have the above drawbacks.

Let's compare the two most popular types of metal poles for power lines - lattice and multifaceted.

Metal lattice poles for power transmission lines

Metal lattice power transmission poles are a classic solution for long-distance transmission of electricity. They can be safely used in areas where the air temperature goes down to 65˚С below zero.

The lattice pole is an impressive carcass made of angled rolled metal, which is assembled using bolted connections. Due to the compactness of the parts, the transportation of the lattice poles is convenient and has a relatively low cost. However, a large number of assembly elements significantly increases the installation time of such poles, which is their main disadvantage.

Anti-corrosion protection of lattice poles is carried out by hot-dip galvanizing, which allows to extend their service life by several decades.

Metal multifaceted poles for power transmission lines

Multifaceted power transmission poles are a new word in the organization of overhead lines, they are in great demand due to their aesthetic appearance and enhanced strength characteristics.

A significant advantage of multifaceted power transmission poles is that they require a small area for installation, in contrast to lattice poles. They are simply indispensable in tight installation conditions.

Installation of multifaceted poles does not take much time and labor costs, due to the small number of assembly units. And the cost of transportation of such poles is low, since it is carried out by placing pole sections inside each other, due to its telescopic design.

Overhead lines built on multifaceted poles are much less likely to fail than ones on reinforced concrete and lattice poles. Metal multifaceted poles are especially good for use in aggressive environments in all climatic regions.

Galvanized multifaceted poles can serve for the benefit of mankind for about 70 years.