With the development of the scientific and technological era, people's requirements for the safety performance of cables are becoming more and more strict. The traditional high-voltage power transmission method has a limited scope of application and has shortcomings that need to be improved. At the same time as the demand is increasing, a high-voltage transmission method between overhead wires and underground cables - overhead cables has been invented.

        With the development of the scientific and technological era, people's requirements for the safety performance of cables are becoming more and more strict. The traditional high-voltage power transmission method has a limited scope of application and has shortcomings that need to be improved. At the same time as the demand is increasing, a high-voltage transmission method between overhead wires and underground cables - overhead cables has been invented.
        Overhead cable (full name overhead insulated cable) is an overhead conductor with an insulating layer and a protective sheath. It is a special cable manufactured by a production process similar to cross-linked cables. It is a new transmission method between overhead conductors and underground cables. . It has the main characteristics of high power supply reliability, good power supply safety, convenient erection and maintenance, and reasonable economy. Its main technical parameters include weather resistance, insulation level, inner and outer semi-conductive shielding layers. Aerial cables are widely used in power transmission at home and abroad.

                                                      
Classification of overhead cables
        General overhead cables are single-core, which can be divided into hard aluminum wire structure, hard-drawn copper wire structure, aluminum alloy wire structure, steel core or aluminum alloy core support structure and self-supporting three-core textured structure according to their different structures (The wire core can be hard aluminum or hard copper wire) and so on.
1. The duralumin wire structure is light in weight, moderate in tension, easy to bend, easy to install, and low in project cost, so it can be installed on existing towers for use. Generally, it is used in renovation or new construction.
2. The structure of the hard-drawn copper wire is heavier, but the pulling force is large, and the ability to resist external force is strong, and the cable can continue to be energized even when the tower is broken. The aluminum alloy wire structure is light in weight and large in tension, and is mainly used in a large-span tower system with a span of 100m.
3. Steel core or aluminum alloy core support structure is generally used for 35kV voltage system, and the span is also large. The support wire (bare wire) and the three insulated phase wires are separated by square insulating parts, and the support wire can be used as a lightning protection wire. Its biggest advantage is that the arc sag is small, and the arc weight is only about 2.4% of the span.
4. The self-supporting three-core twisted structure is used in a system with a medium span. The disadvantage of this cable is that the manufacturing length of the three-core cable is shorter than that of the single core, the joints are more, and there is an outer semi-conductive shielding layer. The end of the cable should be equipped with a terminal head or a stress cone structure like a normal cable.
Advantages of overhead cables
1. High reliability of power supply
Overhead cables greatly reduce all kinds of short-circuit faults, and the failure rate is 4-6 times lower than overhead bare wires. The overhead cable can run along the dense boulevards of Huaihai Road. It has passed the test in different places and runs well, and its power supply failure rate is greatly reduced compared with the original overhead bare wire. Aerial cables will not produce water trees during use, and the insulation quality of the cables will not decrease significantly after years of operation.
2. Good power supply security
The use of overhead cables greatly reduces personal electric shock casualties. When the overhead cable is energized, when the human body or other animals accidentally touch the cable insulation surface, as long as the cable is not broken down, it will not cause harm to humans and animals.
3. Ease of erection and maintenance
Aerial cables can be erected on any kind of poles and towers, and can also be erected along walls. In special cases, they can also pass through trees and be directly fixed on tree poles with hardware. It can be erected on a single circuit or multiple circuits can be erected on the same pole without requiring a wide "electrical corridor". In the installation, it can be erected on the original overhead line, using the original cross arm and porcelain bottle, or a full set of matching hardware and accessories. According to the actual situation of the site, the manufacturer can be asked to make or make some special hardware, so the construction is extremely convenient. There is no need for special inspection and inspection of overhead cables, and there is no short-circuit trip accident caused by branch flashover, residents throwing debris, or accidental collision of crane arms, which greatly reduces the maintenance and repair work of the line.
4. Economical and reasonable
Although the use of overhead cables is more expensive than the use of overhead bare conductors, it is cheaper than ordinary underground installation cables. Therefore, although the one-time investment of overhead cables is slightly higher, the operating costs of overhead cables will be significantly lower than those of overhead bare wires, taking into account other factors. It also reduces the cost of land acquisition and land occupation, and there is no need to cut and prune trees under the line during operation, which saves the cost of felling and pruning, and the most important thing is to reduce the line failure and the direct or indirect losses caused by it. Therefore, its comprehensive cost is obviously lower, more economical and more reasonable.

                                            

 In addition to meeting high electrical performance requirements, high-voltage overhead cable insulation must also have good weather resistance, so that it can work safely in different seasonal environments. The semi-conductive shielding layer and other structural materials strictly comply with the international cable production standards. In addition, zhengzhoujinshui cable & wire group will also customize according to your needs. Welcome to consult and purchase.