In the choice of power cable conductors, people have gone through copper, aluminum, iron, nickel, silver, gold, etc., but practice has proved that copper and aluminum are the most suitable materials for carrying current, and are currently the most important choice for wire and cable in the world. Gold, silver and silver-nickel alloys are only used in small amounts, mainly in integrated circuit boards, relay contactors and circuit breaker contacts, and aerospace.

The amount of copper once stored in China is small, coupled with being used as strategic materials, and vigorously promote the use of aluminum alloy cables as power wires.

With aluminum core or copper core cable has always been the topic of cable selection debate, with the development of urbanization in China, the urban distribution network as the infrastructure of urban construction, the demand for aluminum alloy power cables is increasing, and the proportion of power cables in the cost of power grid construction has increased significantly. At present, there is excess capacity of electrolytic aluminum in China, and the mechanical properties of aluminum alloy cable are more excellent than that of pure aluminum core cable, and the voice of using aluminum alloy cable is rising again. The differences of structure size and electrical performance between copper core and aluminum alloy cable in engineering applications are analyzed and compared, and some problems need to be considered when selecting aluminum alloy cable are put forward.

Cable laying methods mainly include direct burial, cable trench, row pipe, tunnel, bridge, underwater laying, etc. In the cable channel, the pipe laying accounted for 46.4%, the direct buried laying accounted for 26.3%, the cable trench laying accounted for 4.6%, the tunnel laying accounted for 8.3%, and the bridge laying accounted for 4.4%. Compared with copper, in the case of the same section and length, the conductivity is 61.8% of copper, the carrying capacity is about 78% of copper, the specific gravity of copper is 8.9g/cm3, the specific gravity of aluminum is 2.7g/cm3, the same cross-sectional area cable, the quality of aluminum alloy cable is only more than half of the copper core cable.

Due to the light weight of the aluminum alloy power cable, it is especially suitable for long-span buildings, such as cable laying in stadiums, exhibition centers and other buildings.

In addition, for high-rise buildings, the use of aluminum alloy cables can reduce the difficulty and workload of vertical cable laying, save labor costs, and also reduce the risk of body damage that may be caused by cable construction.

Since the melting point of aluminum is 660 ° C, aluminum alloy cables should not be used for fire fighting lines requiring continuous power supply in disaster relief, and special fire protection cables should be used.

The channel resources of cable laying are also one of the main costs of cable construction and operation. Nearly half of the cables in the urban power grid are laid in rows. When aluminum alloy cables are laid in rows, the diameter of the rows is larger than that of the copper core cables by two specifications or two pipe holes, so the selection of aluminum alloy cables increases the construction and operation costs of the rows.

After increasing the section of other laying methods, it will also increase the land area, increasing the construction and operating costs.

Aluminum alloy power cable in laying installation. The tensile force in different directions is generated at each bend, and the dynamic pressure resulting in cable damage is generated, and the dynamic pressure generated when the cable is laid and installed is much larger than when the cable is stationary, so in all cases, the bending radius of the cable should be as large as possible.

Under the premise of meeting the current load and energy loss, the direct cost of aluminum alloy cable, that is, the cost of the cable body is lower than that of copper cable, because the weight of aluminum alloy cable is lighter than that of copper core cable, aluminum alloy cable is more suitable for long-span buildings, which can greatly reduce the load on the building steel structure and save the cost of steel structure.

In addition, the difficulty and workload of vertical cable laying can be reduced for high-rise buildings. In some low-voltage distribution systems, the cable channel resources are abundant, and aluminum alloy power cables can be used in places where there are no multiple cables laid in parallel.

However, with the development of the urban distribution network, the load density is getting higher and higher, and the number of cables laid in the cable channel is also increasing. For the shortage of cable channel resources, short circuit current in the selection of aluminum alloy cable can not only consider the direct cost of aluminum alloy cable, but also consider the comprehensive cost, such as the selection of aluminum alloy cable increases the size of the cable channel, too dense laying makes the flow rate reduced with the reduction of cable spacing, capacitive current increases the need to increase the arc rejection coil capacity and other construction and operating costs.

In addition, the maximum allowable short-circuit temperature and thermal stability coefficient of the aluminum alloy cable are lower than that of the copper cable, and the thermal stability check should be carried out during the design to ensure the safe and reliable operation of the power grid.

Qingdao Tianxing Cable Co., Ltd. is a technology enterprise specializing in the production of wire and cable in Shandong Province, with more than 150 sets of domestic excellent cable production equipment and testing equipment, excellent production technology, modern testing equipment, to ensure stable product quality and timely supply. The company's main products are power cable, mineral cable, high life wire and cable, radiation crosslinked cable, control cable, computer cable, photovoltaic cable, communication cable, data cable, low smoke halogen free cable, flame retardant series wire and cable.

(Part or all of the article is reproduced from the network, only for transmission, if copyright, please contact, please understand.)