Medium voltage overhead lines play a key role in ensuring the supply of electricity to various areas, from urban areas to rural areas. Their significance results from the function of transmitting electricity at medium voltage levels, usually in the range from several to several dozen kilowts. In this article, we will focus on discussing the essence of average voltage overhead lines, their structure, applications and importance for electrical infrastructure.
What cables are used in overhead lines?
In medium voltage overhead ropes, various types of cables are used that must meet certain requirements to ensure reliability and efficiency of the power system. In the case of cables in the cover, intended mainly for the main lines and branches, single cables with a rated cross -section of 70 mm² are preferred, with the possibility of using 120 mm² cables for the main lines. The key feature of these cables is their high permissible temperature of long -term operation, of at least 70ºC, and the production of almgsi alloy wires with an additional moisture barrier and insulating cover from thermoplastic polyethylene resistant to UV -resistant thermoplastic polyethylene. To stretch the line, equipment such as equipment as rope handles.
On the other hand, full -insulated cables, also known as universal cables, are characterized by a cross -section of 70 mm² for Al Wył in the main line and branches, with a permissible cross -section of 10 mm² for veins in the case of branches. These cables are characterized by a high permissible temperature of long -term work and resistance to high temperatures in the case of short circuits. In their construction, one or multi -stream work veins are used, twisted pressed from Al or CU wires, and an insulation coating made of XLPE network polyethylene. The key principle regarding both types of cables is to avoid connecting them in the subtraction section, which is important for the safety and reliability of the entire power system. Thanks to this, the failures that they succumb tooverhead lines.
What should poles look like for overhead lines?
Power for overhead lines is a key element of power infrastructure, whose reliability and durability are extremely important for the stability of energy supply. The basic solution is the single -core rotation poles with a minimum length of 13.5 m. However, in situations justified by special technical or administrative conditions, it is also allowed to use other types of columns, such as grille, tubular, composite or wooden poles, after prior arrangement with relevant institutions. The key issue is to ensure a permanent marking of poles, enabling the manufacturer's identification, year of production and verification of technical parameters. The poles should be made of high quality concrete and protected against corrosion, which is important for their durability and reliability. It is also worth emphasizing that branches should be specially strengthened to ensure the stability of the entire structure. Requirements for poles and steel elements, such as appropriate marking or corrosion protection, are strictly defined and must be observed in accordance with industry standards. Thanks to the appropriate selection and assembly of poles, you can not only ensure the safety and reliability of overhead lines, but also their effective operation for many years.
Insulation in medium voltage overhead lines
Insulation in medium voltage overhead lines play a key role in ensuring the safety and reliability of the entire system. Requirements for insulation of 15 kV/20 kV overhead lines include the use of composite insulators both as hanging (extraction) and support insulation. Ceramic insulators are also allowed in the event of existing insulation, provided that this applies only to part of the line. Dischase composite insulators must meet a number of criteria, such as the rated, thunder -tired test tube, rated alternating voltage with wet, rated tensile strength, and the rated way of passing.
Materials used for the production of insulators, such as epoxy resin, fiberglass, silicone rubber must meet certain standards and standards. Insulators must also be equipped with a permanent marking enabling the identification of the manufacturer, serial number and year of production. The combination of an insulator with a screw-clay hanger and anti-corrosion protection of the fittings are also subject to specific requirements. By using insulation that meet specific standards and standards, it is possible to ensure reliability and safety of medium voltage overhead lines.
The exact criteria for materials, strength and assembly and marking processes are of key importance for the proper functioning of overhead lines. By strict compliance with insulation requirements, it is possible to ensure reliability and safety of electricity supply by medium voltage lines.
