Electrical performance of fiber optic cable
1. The current carrying capacity of the cable
◆When the cross-sectional area of the alloy conductor is 1.5 times that of copper, the electrical properties of the alloy conductor and the copper conductor are the same, and the same current-carrying capacity, resistance, and pressure loss are achieved.
◆The resistivity of aluminum alloy is between aluminum and copper, slightly higher than aluminum, but lower than copper. Under the premise of the same cut-off capacity, the weight of the aluminum alloy conductor of the same length is only half of that of copper. If the conductivity of copper is calculated as 100%, the conductivity of the alloy conductor is about 61.2%, the specific gravity of the alloy is 2.7, and the specific gravity of copper is 8.9, then (8.9/2.7)×(0.612/1)=2, which is 2 The resistance per unit weight of copper is the same as the resistance of 1 unit mass of alloy. Therefore, when the cross-sectional area of the alloy conductor is 1.5 times that of copper, its electrical properties are the same, that is, the same interception capacity, resistance, and voltage as copper are achieved. loss.
◆There are many factors that affect the interception of power cables, such as; line characteristics (such as working power, current type, frequency, load factor); wire and cable structure (such as conductive core structure, number of cores, type of insulation material, shielding layer) And the structure and materials of the inner and outer protective layer, total outer diameter); laying conditions (such as laying in the air, laying in the pipeline, laying directly in the ground, laying in the underground channel, laying in the water); the maximum allowable working temperature and surroundings of the conductive core Environmental conditions (such as air and soil temperature, soil thermal resistance coefficient, proximity effect of surrounding heat sources), etc.
2. Reduce the external cross-section of the cable
In the production process of aluminum alloy cable, Germany's most advanced compression technology enables its conductor fill factor to reach 93%. And the aluminum alloy cable uses silane cross-linked polyethylene, this kind of insulation only needs 2/3 of the thickness of polyvinyl chloride to far exceed the conventional insulation performance. The filling factor of copper can generally only reach 80%, and the commonly used insulation is polyvinyl chloride, so the outer diameter of the aluminum alloy cable can only be increased by less than 11% on the basis of the copper cable, and it can have the same electrical properties as copper. It can be seen that the use of aluminum alloy cables does not need to change the pipe design of the original copper cables. (Generally, the size of the laying pipe designed by the designer is 150% of the copper cable. Considering the problem of capacity increase, the size of the laying pipe is increased to 200% of the copper cable, so the pipe penetration is not a problem.)
3. Reduce cable loss
Non-magnetic materials, will not produce eddy current, can reduce the loss of the line. The aluminum alloy belt-armored locking material is a non-magnetic material, even if there is a three-phase unbalanced current, it will not produce eddy current, which can reduce the loss of the line.
