Some knowledge points of overhead cables

2022-06-22

Aerial cables are overhead conductors with insulating layers and protective sheaths. They are special cables made by a production process similar to cross-linked cables. They are a new type of transmission between overhead conductors and underground cables. Aerial cables are single-core, which can be divided into hard aluminum wire structure, hard copper wire structure, aluminum alloy wire structure, steel core or aluminum alloy core support structure and self-supporting three-core laminated structure (the wire core can be hard aluminum or hard copper wire). Its main features are high reliability of power supply, good power supply, convenient erection and maintenance, economical and reasonable. 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.

The role of overhead cables: According to overhead cables, everyone's electricity is delivered to each area, and then sent to each residential area to become household electricity, so overhead cables are very important to everyone.

Advantages of overhead cables:

1. The reliability of the power supply system is high. The selection of overhead cables can greatly reduce various common short-circuit faults (especially the common short-circuit faults of bare overhead transmission lines). Equipment failure rate is 4-6 times lower compared to exposed overhead transmission lines.

2. The safety factor of the power supply system is good, and the use of overhead cables can greatly reduce personal electric shock accidents. When the overhead cable is powered on, and the body or other small animals accidentally touch the surface of the cable insulation, if the cable does not penetrate, it is not easy to cause adverse effects on people and animals.

3. Construction and maintenance are very convenient. Aerial cables can be run on various types of tower poles or along walls. In special cases, they can also travel through the woods. They can be attached to the main pole right away with hardware.

4. Rationality and validity. While overhead cables are more expensive than bare transmission lines, they are less expensive than common underground cables. Therefore, its comprehensive project cost is significantly lower, more economical and more effective.

The overhead cable is not an ordinary oil-paper insulated cable or a cross-linked insulated cable directly hung on an overhead tower, but a special cable manufactured by a similar cross-linked cable production process. Aerial cables are mainly used for urban streets and green spaces, overhead lines near buildings, urban construction sites and lead wires of transformers. It has the characteristics of convenient installation and high safety, and plays a good role in ensuring urban industrial electricity and residential electricity. When laying the cable, the ambient temperature should not be lower than -20. When a short circuit occurs (the duration does not exceed 5S), the allowable temperature of the cable is 250 for XLPE insulation and 150 for HDPE insulation.

The above are some knowledge points about overhead cables. I hope you can study and understand the relevant knowledge carefully and choose the products and equipment that suit your needs.