The working principle of steel-cored aluminum stranded wire utilizes a "rigid-flexible" structure. The inner steel core bears the mechanical load, while the outer aluminum strands are responsible for electrical conduction. This design fully leverages the high strength of steel and the excellent conductivity of aluminum. Simultaneously, by utilizing the skin effect of alternating current, the current mainly flows in the outer aluminum portion of the conductor, reducing the impact of the steel core on conductivity efficiency.
Steel Core ("Rigid"): Located at the center of the conductor, it is composed of galvanized steel wire or high-strength steel strands. It primarily bears the mechanical tension of overhead lines, such as its own weight, wind load, and icing, ensuring the conductor does not break over long distances and large spans.
Aluminum Stranded Wire ("Flexible"): Wrapped around the steel core, it is composed of multiple strands of hard aluminum wire. It primarily undertakes the task of electrical energy transmission. Due to its high conductivity (approximately 61% IACS), it effectively reduces resistance loss.
Skin Effect Optimizes Conductivity: Due to the skin effect of alternating current, current tends to flow on the surface of the conductor. Steel-cored aluminum stranded wire utilizes this characteristic, placing highly conductive aluminum in the outer layer. Even if the inner steel core has poor conductivity, it will not significantly affect the overall conductivity efficiency.
Synergistic Improvement of Mechanical and Electrical Properties:The presence of the steel core significantly increases the tensile strength of the conductor, making it suitable for traversing complex terrains such as valleys and rivers.
The aluminum-clad steel core structure also avoids electrochemical corrosion caused by direct contact between steel and aluminum, extending the conductor's lifespan, making it particularly suitable for coastal or polluted areas.
Operating Temperature and Current Carrying Capacity Advantages: Ordinary steel-cored aluminum stranded wire allows for long-term operating temperatures of 70℃, while heat-resistant types can reach 150℃. Short-term operating temperatures can withstand 180–230℃, and the continuous allowable current carrying capacity is 1.5–2.5 times that of ordinary conductors of the same specification.