Aluminum- and copper-core wires and cables have long been compared, and while each type has its own advantages and disadvantages, aluminum alloy cables offer advantages in terms of light weight and relative price. Today, we'll focus on aluminum alloy cables, providing a basic introduction and encompassing their advantages and disadvantages.
1. Overview of Aluminum Alloy Cables
Aluminum alloy cables are a new type of power cable, using AA8030 series aluminum alloy as conductors and utilizing advanced technologies such as a special compression process and annealing treatment.
Alloy power cables address the shortcomings of pure aluminum cables. While their electrical conductivity isn't improved, their bending performance, creep resistance, and corrosion resistance are significantly enhanced, ensuring continuous and stable performance under prolonged overloads and overheating. Using AA-8030 series aluminum alloy conductors significantly improves the electrical conductivity and high-temperature resistance of aluminum alloy cables, while also addressing the creep issues associated with pure aluminum conductors. Aluminum alloys have an electrical conductivity of 61.8% of the IACS rating of copper, the most commonly used benchmark material, and a current carrying capacity of 79% of copper, exceeding the standard for pure aluminum. However, for the same volume, the actual weight of aluminum alloy is approximately one-third that of copper. Therefore, for the same current carrying capacity, aluminum alloy cables weigh approximately half as much as copper cables. Replacing copper cables with aluminum alloy cables can reduce cable weight, lower installation costs, reduce wear on equipment and cables, and make installation easier.
II. Advantages and Disadvantages of Aluminum Alloy Cables
Advantages of Aluminum Alloy Cables
1. Creep Resistance
The alloy material and annealing process of aluminum alloy conductors reduce the conductor's tendency to "creep" under heat and pressure. Compared to pure aluminum, creep resistance is improved by 300%, eliminating the problem of relaxation caused by cold flow or creep.
2. Tensile Strength and Elongation
Compared to pure aluminum conductors, aluminum alloy conductors have significantly improved tensile strength and elongation by up to 30% due to the addition of special ingredients and processing techniques, making them safer and more reliable.
3. Thermal Expansion Coefficient
The thermal expansion coefficient is used to calculate the dimensional change of a material with temperature changes. Aluminum alloy has a coefficient of thermal expansion comparable to that of copper. For many years, aluminum connectors have reliably worked with both copper and aluminum conductors. The majority of electrical connectors in use today are made of aluminum, making it particularly well-suited to aluminum alloys. Therefore, the expansion and contraction of aluminum alloy conductors and connectors are perfectly aligned.
4. Connection Performance
Electrical connections made with aluminum alloys are just as secure and stable as those made with copper conductors. The composition of aluminum alloys significantly improves their connection performance. When the conductor is annealed, the addition of iron imparts high creep resistance, ensuring a stable connection even under prolonged overload and overheating.
5. Strong Weight-Bearing Capacity
Aluminum alloys improve the tensile strength of pure aluminum. Aluminum alloy cables can support a length of 4,000 meters, while copper cables can only support 2,750 meters. This advantage is particularly evident when wiring long-span structures, such as stadiums.
6. Corrosion Resistance
Aluminum's inherent corrosion resistance stems from the thin, durable oxide layer that forms on the aluminum surface when it comes into contact with air. This oxide layer is exceptionally resistant to all forms of corrosion. The addition of rare earth elements to the alloy further improves the aluminum alloy's corrosion resistance, especially electrochemical corrosion.
7. Flexibility
Aluminum alloy offers excellent bending properties. Its unique alloy formula and processing technology significantly enhance its flexibility. Aluminum alloy is 30% more flexible than copper and 40% less resilient. While the bending radius of typical copper cables is 10 to 20 times the outer diameter, aluminum alloy cables have a bending radius of only 7 times the outer diameter, making terminal connections easier.
8. Armor Characteristics
The aluminum alloy interlocking armor is used. The interlocking structure between the layers ensures that the cable can withstand strong external forces. Even under high pressure and impact, the cable is not easily penetrated, thus enhancing safety.
9. Compression Characteristics
Using unconventional compression technology, the compression coefficient reaches 0.93, and the compression coefficient of special-shaped wires can reach 0.95, a domestic first. Through extreme compression, the aluminum alloy's lack of bulk conductivity can be compensated, making the stranded conductor core behave like a solid conductor. This significantly reduces the core's outer diameter and improves conductivity. At the same current-carrying capacity, the conductor's outer diameter is only 10% larger than that of copper cable.
2) Disadvantages of Aluminum Alloy Cables
1. Corrosion resistance: 8000 series aluminum alloys are inferior to standard aluminum.
2. Temperature resistance: Aluminum alloys differ significantly from copper.
3. The thermal expansion coefficient of aluminum alloys is much higher than that of copper, with AA8030 aluminum alloy even exceeding that of standard aluminum.
4. Aluminum alloys have not addressed the issue of aluminum oxidation.
5. Aluminum alloy cables have improved stress relaxation and creep resistance, but are far inferior to copper.
6. Aluminum alloy cables have not addressed the issue of aluminum connection reliability.
7. Inconsistent quality control (alloy composition) of domestic aluminum alloys leads to poor creep resistance.
8. The manufacturing process for aluminum alloy cable joints is complex and prone to potential safety hazards.
The current market situation is that aluminum alloy cables are difficult to gain public acceptance. I believe this is due to the lack of national standards, which has caused confusion in the industry. Moreover, aluminum alloy cables should be clearly distinguished from traditional cables in terms of usage occasions to give full play to their advantages. In fact, aluminum alloy cables have been used in the United States for more than half a century, and it can be seen that they are still very practical and very reliable.
