Cable selection points, Guangdong cable manufacturers online explanation
Release time： 2022-06-08 13:58
Guangdong cable manufacturers believe that the construction technology of large section aluminum core cable intermediate joint has not fully solved the problem of reliable, stable and mature field crimping technology. Compared with aluminum alloy copper, the same section and length, electrical conductivity is 61.8% of copper, current carrying capacity is about 78% of copper, the specific gravity of copper is 8.9g/cubic centimeter, the specific gravity of aluminum is 2.7g/cubic centimeter. With the same cross-sectional area, aluminum cables weigh only half as much as copper cables.
Guangdong cable manufacturers say aluminum cable is especially suitable for laying cables in long-span buildings, such as stadiums and exhibition centers, because of its light weight. Using aluminum cable can reduce the load of building steel structure and save the cost of steel structure. In addition, the use of aluminum cables in high-rise buildings can reduce the difficulty and workload of vertical cable laying, save labor costs, and reduce the risk of injury to human body caused by cable construction. Because the melting point of aluminum is 660, aluminum cables should not be used for fire fighting lines that require continuous power supply in case of a fire.
Guangdong cable manufacturers believe that the selection of conductor section should not only consider the initial cost of the cable line, but also consider the power loss cost during the cable life. Therefore, the cable section should be selected from the economical current density. According to the cable section specification distribution, the section of aluminum cable is about 1.5 times larger, and the electrical parameters such as load capacity and voltage drop are comparable to those of copper. In the case of similar energy consumption, the section of aluminum alloy cable is two specifications larger than that of copper cable, that is, aluminum cable is two specifications larger than copper cable to achieve similar carrying capacity. Increasing the cross-sectional area of the conductor has an effect on the cable laying, the structure size and the electrical performance of the cable channel.
Guangdong cable manufacturers consider channel resources for cable laying as one of the main costs of cable construction and operation. Nearly half of the cables in the urban power grid are piping. When aluminum cable is used for pipe distribution, the diameter of copper cable is one or two specifications or the aperture ratio is two pipe holes, which increases the construction and operation cost of aluminum cable distribution. Increasing the cross section of other paving methods also increases the footprint and construction and operating costs. Cable laying and installation. Each bend creates tension in different directions, and dynamic pressure can cause cable damage. Moreover, the dynamic pressure generated by cable laying, installation and traction is much greater than that generated when the cable is stationary, so the bending radius of the cable should be as large as possible in any case.
Guangdong cable manufacturers believe that the choice of cables should also consider the cable under normal and short circuit conditions of the allowable temperature. The allowable temperature of the conductor of copper and aluminum cable is different in normal and short circuit conditions. The allowable temperature of aluminum cable in short circuit condition is lower than that of copper cable, which should be considered in the selection.
Guangdong cable manufacturers believe that the selection of cables should not only determine the allowable current according to the allowable temperature, but also check the thermal stability in the case of short circuit. When thermal stability is insufficient, increase cable section until appropriate. Because aluminum cables increase the cable diameter, the cable spacing decreases and the number of cables increases, which reduces the correction factor, or cable load. In order to meet the working current requirements, it may be necessary to select a larger cross section of the conductor. Therefore, when choosing aluminum cable, it is necessary to consider the problems of increasing section, reducing cable spacing and reducing allowable flux.