1. Electrical energy in the transmission process of loss depends on the conductor resistance rather than resistivity: cable conductor commonly used in copper and aluminum two kinds of materials. Because the resistivity of the aluminum conductor is larger than that of the copper conductor, it is concluded that the loss of the conductor with aluminum as a cable should be larger than that of the copper conductor in the process of power transmission. Theoretically, the loss of electrical energy is directly proportional to the resistance of the conductor, inversely to the section.
It is absolutely not scientific to conclude that aluminum has a greater loss than copper.
2. Under the same load flow, aluminum alloy cable section is 1.5 times times the copper core cable: According to GB/T 3956-2008 "cable conductor", in 20 ℃, a copper conductor section of the DC resistance value and corresponding to the other specifications of the direct current resistance of the aluminum conductor equivalent. From the point of view of electric energy loss in power transmission, a copper conductor core power cable can be replaced by a direct current resistance equivalent aluminum conductor cable, at which time the load flow of the aluminum cable is larger than that of the copper cable. Electrical performance compared with copper, in the same section length, the conductivity is 61% of copper, and the load flow is about 78% of copper.
According to the specification distribution of cable cross-section, the section of aluminum alloy cable is increased 1.5 times times, and the electric parameters such as load flow and voltage drop are equal to that of copper.
3. Under the same load flow, the diameter of the aluminum alloy conductor is about 1.2 times times the core conductor: does increasing the conductor diameter increase the conductor diameter too much, thus affecting the installation?
The following methods can be used to solve, first of all, in the design of the aluminum alloy cable diameter factor; Secondly in the manufacture of the conductor compression technology, the pressure coefficient of 0.93, so that the outer diameter of the aluminum alloy cable than the copper core cable only increased by about 10%, the diameter factor to minimize.
4. Equivalent section length of the same time, the weight of aluminum alloy conductor is copper conductor 50%: Because of the difference in the proportion of the two, even if the aluminum alloy cross-section, but because of the smaller proportion, can reduce the weight of the conductor. 5. Good joint performance due to the addition of iron, magnesium, rare earth and other elements in aluminum: greatly improved the toughness after annealing and high resistance to creep performance. In practice, the copper-aluminum connection has been the most critical issue. Copper and aluminum (or aluminum) if direct, connection contact, there are different metal materials, there is a potential difference in the humid air will occur electrochemical corrosion. In the power system, this corrosion will increase the contact resistance, so that the joint heating, is a safe operation of the system hidden danger.
Now the use of new technology made of copper and aluminum joints fundamentally eliminates the past of copper and aluminum joints of the fatal deficiencies, so that the aluminum alloy cable joints safe and reliable, easy to operate.
6. Improvement of mechanical properties: due to the addition of alloying elements such as iron, copper and rare earth in pure aluminum, the comprehensive performance of aluminum alloy is improved, elongation and creep can be improved.
7. High strength: Alloying improves the tensile strength of aluminum alloy. 8. High elongation: elongation to more than 25%, greatly improving the bending performance.
Aluminum alloy cable installation of the minimum bending radius of more than 7 times times the cable diameter can be far less than the gb12706-2008 "rated voltage 1kV to 35kV extruded insulated power cables and accessories," the minimum bending radius of the cable installation is 12 times times to 20 times times the cable diameter.
9. Rebound Small: aluminum alloy cable than copper rebound can be less than 40%, facilitate construction and increase construction safety.
10. Creep Resistance: The special alloy of aluminum alloy conductor and heat treatment process greatly reduce the metal under heating and pressure of the "creep" tendency, compared to pure aluminum, creep resistance can be increased by 300%. 11. Anti-Corrosion: aluminum in the air quickly generated a layer thickness of about 2~4μm dense oxide film, this layer of oxide film is so dense that the air can not enter, so as to prevent the internal metal is further oxidized. The surface of copper can not produce oxide film, so the gas will pass through the surface of the oxide into the interior, and the internal metal continues to occur oxidation, resulting in copper oxidation very quickly.
Because of the addition of rare earth metals in the aluminum alloy conductor, the corrosion resistance of the metal materials with pure aluminum as conductor is improved, and the potential difference between different metals is reduced. 12. High Flame Retardant: aluminum alloy with Lian cable using aluminum alloy conductor, flame retardant silane crosslinked polyethylene insulation, aluminum alloy with Lian structure, can achieve flame-retardant IA class, Refractory IA class, and low smoke without halogen.
Excellent safety performance and economic benefits. 13. Easy to install: Compared with the installation of copper core cable, it is more like the metal conduit and cable integrated together. The practical application eliminates the pipe-piercing work, in the electrical design is clear, may save the bridge frame, may reduce the cost, saves the work time, shortens the time limit, saves the material, reduces the pollution and the energy waste. Because the aluminum alloy cable is lighter than the copper cable weight half.
For high-rise buildings, the difficulty and workload of vertical laying is greatly reduced, which can reduce labor intensity, shorten the construction period and save labor cost. 14. No eddy current loss: Aluminum armored cable using non-magnetic materials, even if there are three-phase unbalanced current, the cable will not produce eddy current, can reduce the loss of the line.