Steel-cored aluminum stranded wire is a widely used overhead conductor in high-voltage transmission lines. It combines the high strength of steel with the excellent conductivity of aluminum, achieving an optimized balance between mechanical and electrical performance.
Core Structure: It consists of an inner galvanized steel core and an outer layer of multiple strands of hard aluminum wire concentrically stranded. The steel core primarily bears the mechanical load of the conductor (such as wind, snow loads, and its own tension), while the outer aluminum strands are responsible for transmitting electrical energy.
Key Characteristics:
High Tensile Strength: The steel core provides strong mechanical support, enabling the conductor to withstand the enormous tensile forces during long-distance installation, making it suitable for lines with large spans and complex terrain (such as crossing rivers and valleys).
Excellent Conductivity: Aluminum's conductivity is second only to copper and silver, and its low density and light weight effectively reduce line resistance loss and installation difficulty.
Economy and Durability: Compared to pure copper conductors, it is less expensive; the aluminum layer has excellent corrosion resistance, especially stable performance in ordinary atmospheric environments, resulting in low maintenance costs.
Optimized Sag Characteristics: The high-strength steel core reduces conductor sag during operation, allowing for larger tower spacing and saving on tower and foundation construction costs.
Skin Effect Utilization: In AC power transmission, current tends to flow on the conductor surface (skin effect). This allows the highly conductive aluminum layer to operate efficiently, while the low-conductivity steel core carries very little current, without affecting overall efficiency.