Wooden supports of power lines: production, weight, service life, installation rules

The use of wood material in the arrangement of the communication infrastructure justifies itself in many ways. One of the key factors of this choice for many users is the low price. Cheap poles themselves are inexpensive and in the process of operation they practically do not require investments in maintenance. Such a solution facilitates the operation of power transmission lines (LEPs) in severe weather conditions. The natural material resists both frosts and squall wind, and also does not undergo degradation under the action of moisture. On the other hand, the wooden poles of the transmission lines have a lot of disadvantages, which, for the most part, consist in modest indicators of strength. One way or another, there are quite a few organizations involved in servicing electric grids that rely on this type of supports.

Preparation of wood raw materials for supports

As a basis for poles supporting power transmission lines, solid arrays of predominantly coniferous species are chosen. As a rule, due to high strength and resistance to external influences for such needs, pine or fir is selected. Sometimes used and larch logs. Regardless of the species selected, each piece is subjected to a thorough examination for fungal and insect damage. This is important for the subsequent maintenance of optimal technical and operational indicators. Depending on the technology by which the manufacture of wooden poles will be carried out, the primary treatment of the substrate may include operations of peeling and debarking. With the help of special machines logs are processed, during which the top layer is removed, so that in the future it does not interfere with the penetration of protective impregnation.

Manufacturing technology of supports

The main stage of production of support logs still involves the execution of machining to form technological openings with holes. The horizontal ends are protected with special pastes already at the stage of basic refinement. If necessary, corrected existing cuts, shots and cracks - they can be eliminated provided that the depth is no more than 10% of the diameter of the workpiece. To ensure accuracy in the machining process, the production of wooden poles of power transmission lines in some enterprises involves the use of special templates. For them, for example, the parameters of grinds and nicks are checked.

Then begins the drying phase, which prepares the wood for impregnation. According to the regulations, protective equipment can be applied only on condition that the moisture content of the massif is not more than 28%. The barked logs are dried in special thermal chambers, which have an unusual design. The fact is that in such units hot air flows are not directed to the workpiece, but circulate around it. Thus, cracking and overheating of the material are not allowed.

Impregnation of supports

The use of special impregnations aims to protect the wood from decay, breakdown of the structure and, in general, loss of performance before external influences. In particular, the protective compounds protect the wooden supports of the power line from fungal attack, insect repellent and the development of mold. Such protection, for example, provides an antiseptic water-soluble drug from the family of SSA. This product is highly effective and environmentally friendly, which made it one of the most common types of impregnation.

In the first stage, after application, a vacuum is formed in some way, which helps to remove excess moisture from the wood pores. Later active components of the composition dissolve throughout the structure of the tree, strengthening it and forming a protective barrier.

Dimensions and weight

There are several categories of pillars, which cause differences in size. So, the initial level is logs 9.5 m long, which have a diameter of 160 mm. The weight of this blank is 200 kg. Then follow the medium strength supports, which can reach a length of 11 m, their diameter is already 210 mm, and weight - 300 kg. The most powerful structures from the point of view of the ability to endure physical loads make it possible to construct a wooden support for power transmission lines, the weight of which reaches 400 kg. At the same time, the length remains the same as in the case of medium strength poles, 11 m. However, the diameter of this support increases to 240 mm.

Operational period

Depending on the production technology, the service life on average can vary from 10 to 20 years. This is the average corridor, since there are also logs, the working resource of which does not exceed 5 years, as well as high-strength structures that retain their original properties after 50 years. As a rule, the warranty service life of wooden poles LEP does not exceed 10 years. In practice, most commonly, ordinary poles of this type are used for 5-7 years. Such a short term is due to the lack of proper maintenance of the facility or the fact that at the manufacturing stage, no special impregnation was used at all. By the way, depending on the characteristics of protective equipment, the working period of the support can last for 4-6 years. Modern drugs are valid for up to 15 years. However, a lot depends on how well the processing technique was performed by the composition.

Quality control

During the manufacturing process of the support, several stages of quality control pass. The first involves examining the element of the future power line for geometrical accuracy. After that, the stock is sent for drying. Before impregnation, the material is checked for a moisture index, which should not exceed 28%. Next, control check measures are provided, during which the characteristics of the protective device to which the wooden supports of the transmission lines were processed are determined. The installation rules require that the material be delivered to the installation site with an optimally impregnated structure. To comply with this condition, technologists assess the depth of impregnation, and on the basis of the analysis results, a corresponding quality certificate is formed.

Reinforcement Assembly

During the assembly process, the rig is equipped with a functional tool that will be required when connecting to the power line. The layout of the installation activities usually involves marking the location of the hooks, creating holes for the hooks and directly installing the reinforcement with insulators. The points for placing the hooks are marked with a template, which can be made from a piece of an aluminum rectangular bus. As a rule, the installation of wooden poles of transmission lines with the use of drilling is performed on special machines in the factory. This ensures high accuracy of work and corresponding quality. However, during transportation, the assembled structure can be damaged, so the workpiece processing with mounting actions is sometimes carried out directly at the installation site. In this case, a cordless power tool is used in the form of a screwdriver with a drill function.

Installation technique

Most often, the installation is performed using drilling crane machines. Only in some cases when working with heavy or oversized structures, it is envisaged to use tractor cranes. On the installation site, a pit is first formed, into which a pole will be installed. It must be carefully tampered with, if necessary, drainage and covered with special insulators. Next, the direct installation of the wooden poles of the transmission lines is carried out using the technique. The working bodies of the crane or crane-crane machine fix the prepared column, and then move it to the pit. But this applies to lightweight supports, whose height does not exceed 10 m. Heavy logs are installed in pits with concrete prefixes - this is a kind of foundation in which a mechanical fixation of the column is made.

Producers of supports

In Russia, the products in the form of components and consumables for equipping power transmission lines are rather widely represented. One of the largest representatives of this niche is the Kotelnich mast-impregnation plant. This company has been manufacturing high-quality wooden poles for more than 30 years, and in recent years has successfully switched to high-tech automated manufacturing of products. However, many manufacturers of wooden poles of transmission lines in Russia are engaged in the renewal of capacities, among which the enterprises of OSMK and ProfTrade are also singled out. If the first mentioned manufacturer is oriented specifically to the production of supports, then in the range of these companies, it is also possible to find reinforcing components, insulating materials and auxiliary elements specially for the characteristics of specific supports.

Reinforced concrete structures as an alternative

At once it is necessary to note, that from the point of view of operation it is more profitable to use ferro-concrete designs. They are more reliable in all technical parameters, but, of course, are much more expensive. In turn, the wooden poles of the transmission lines, even in the best designs, can only approximate the characteristics of reinforced concrete structures with some success. This material and under condition of high-quality impregnation can not serve as much as a concrete structure. However, a low service life is offset by the cost. Regular replacement of poles with intervals of at least 5 years is quite within the estimate for the use of reinforced concrete analogues.

Conclusion

Wooden supports designed to organize power lines, confirm the value of natural building materials. Even modern plastics based on fiberglass can not replace such poles. Of course, this does not mean that the wooden poles of the transmission lines benefit from composites in terms of strength and security from external destructive influences. Moreover, the same fiberglass for a number of characteristics will outstrip the concrete structures. But if you evaluate materials in a combination of qualities, then wood is more practical. It is easier to process, produce, deliver, and perform assembly operations with it.