What equipment is used to build overhead and cable power lines?
The construction of overhead and cable power lines requires the use of various types of equipment. Individual facilities are selected depending on the type of line, its purpose and environmental conditions. This ensures correct operation and interaction of all parts of transmission and distribution lines. It is worth taking a closer look at what type of equipment and tools for the construction of power lines are commonly used by investors.
Cable lines construction
Cable power lines can be used in both densely built-up and industrialized areas. They are usually invisible to the user and can be used for direct and alternating current. A cable line consists of a multi-core cable, a multi-phase cable bundle or several cables connected in parallel with cable accessories. Cables are laid along a specific route and connect electrical devices.
Overhead lines construction
The wires of overhead power lines are suspended on poles or towers. The supporting structures can be made of various materials, such as wood, concrete, steel or composites, depending on technical requirements and field conditions. Steel-aluminium or aluminium cables of various designs are also used here, for example, cables with reinforced core.
Reliability of cable joints
In the case of cable power lines, the equipment used must have the same degree of reliability as the cable itself. Appropriate electrical and mechanical properties are ensured by joints and cable heads. LV, MV and HV cable lines can be equipped with them. Their design depends on factors such as the type of cable, rated voltage, manufacturing technology and the number and cross-section of conductors. Pass-through and transition joints are often used. The former allow you to connect different sections of the same type of cable, while the latter create connections between different types of cables, for example three-phase cables with plastic insulation.
Dedicated connectors and terminals
Other important elements of cable line equipment are connectors and terminals. They are used to permanently connect the conductors of copper and aluminium power cables in devices most often used indoors. This type of connectors can be used to create connections of single-wire and multi-wire cables installed under low and medium voltages. The installation methods depend on the voltage level and the design of the cable cores. In addition, manufacturers offer universal connectors and terminals that facilitate the connection of various types of conductors, taking into account the selected cross-section range.
Osprzęt do budowy linii kablowych
Variety of joining technologies
The components used, including cable joints, can be made using tape, heat-shrinkable, cold-shrinkable or poured technology. Hybrid solutions are also becoming more and more popular, i.e. connectors and cable heads, which at the same time guarantee adequate electrical and mechanical strength, as well as effective sealing and protection against moisture. They are used to connect or create terminations of working and return conductors.
Cable mounting heads and holders
Cable accessories for connection to the overhead power line mainly include components such as cable heads, meters, surge arresters, as well as various types of holders for mounting cables on the pole structure. The heads are installed on previously prepared cables and terminated with a special clamp, which is screwed to the overhead wire holders or mounted using a pin and screw clamps.
Cable heads are used to connect medium, high and low voltage cables to switchboards, transformer stations and overhead power lines. They also function as cable terminations inside or outside buildings, in the so-called cable cabinets. Surge arresters are, as their name suggests, accessories that protect cables and connected devices against the effects of atmospheric or switching overvoltage.
Lifting and assembly equipment
Various types of lifting and assembly devices are used for the installation and maintenance of overhead and cable lines. These include lifts, winches, cranes and work platforms. Drones, i.e. remotely controlled flying vehicles, are also helpful in the construction of transmission lines. Thanks to them, it is possible to monitor the progress of work and verify the parameters of the power line under construction. The work is facilitated by hydraulic drum lifts, as well as cable ramps designed for unwinding and rolling cables, electric wires, optical fibres, cords and ropes.
Other power overhead line equipment
Overhead lines construction cannot be complete without accessories such as hooks, hook screws, brackets, handles or hook shanks. They are located on installations such as low-voltage overhead lines. The screws are used to hang the handles and are screwed to the supporting structures. The holders are made of steel and intended for installing cables on seatposts and tubular booms. The hooks are used to hang through and guy holders on round poles, while the hook shanks allow for mounting standing insulators.
Equipment and tools for the construction of a power line are selected taking into account many factors, including the purpose of the line, its type, environmental conditions and standards applicable in the installation region. The individual elements can be used in various combinations, depending on requirements, for example in situations such as the expansion of installations or the design of substations. In this way, it is possible to ensure the expected efficiency and a high level of safety during the execution of works.