Classification And Introduction Of Power Cables

Classification and introduction of power cables

By voltage class

According to the voltage level, it can be divided into medium and low voltage power cables (35 kV and below), high voltage cables (above 110 kV), ultra-high voltage cables (275-800 kV), and UHV cables (1000 kV and above). In addition, it can also be divided into AC cables and DC cables according to the current system.

By insulating material

1. Oil-impregnated paper insulated power cable is a power cable with oil-impregnated paper as insulation. Its application history is the longest. It is safe and reliable, has a long service life and is inexpensive. The main disadvantage is that the laying is limited by the drop. Since the development of non-drip paper-impregnated insulation, the problem of drop limit has been solved, allowing oil-impregnated paper insulated cables to continue to be widely used.

2. Plastic insulated power cables Power cables whose insulation layer is extruded plastic. Commonly used plastics are polyvinyl chloride, polyethylene, and cross-linked polyethylene. The plastic cable has the advantages of simple structure, convenient manufacturing and processing, light weight, convenient laying and installation, and is not limited by the laying drop. Therefore, it is widely used as medium and low voltage cables and has a tendency to replace sticky impregnated oil-paper cables. Its biggest disadvantage is the presence of dendritic breakdown, which limits its use at higher voltages.

3. Rubber insulated power cable The insulating layer is made of rubber plus various compounding agents. After fully mixing, it is extruded and wrapped on the conductive wire core, and is formed by heating and vulcanization. It is soft and elastic, suitable for frequent movement and small bending radius.
The rubber materials commonly used for insulation include natural rubber-styrene-butadiene rubber mixture, ethylene propylene rubber, butyl rubber, etc.

By voltage class

1. Low-voltage cables: suitable for fixed laying on transmission and distribution lines with AC 50Hz and rated voltage of 3kv and below for electric energy transmission.

2. Medium and low voltage cables: (generally refers to 35KV and below): PVC insulated cables, polyethylene insulated cables, XLPE insulated cables, etc.

3. High-voltage cables: (generally 110KV and above): polyethylene cables and XLPE insulated cables, etc.

4. Ultra-high voltage cable: (275～800KV).

5. UHV cable: (1000KV and above).