1. The steel core bears the entire mechanical load of the conductor. The aluminum strands primarily contribute to carrying current, not mechanical load. Therefore, the operating temperature of the conductor is not limited by the softening properties of the aluminum strands.
2. The smaller diameter of the steel-cored aluminum wire reduces icing and wind load. The smaller diameter and smoother outer surface reduce the aerodynamic coefficient, mitigating the damage caused by wind vibration and galloping. A larger aluminum cross-sectional area increases current carrying capacity and reduces line losses. The smoother outer surface also reduces corona discharge and radio interference.
3. It exhibits good corrosion resistance and thermal stability, with no significant change in sag under high-temperature operating conditions. It also possesses inherent damping characteristics, which help reduce wind vibration.
Most of the performance advantages of steel-cored aluminum wire are due to the use of fully annealed aluminum material in the strands. Such aluminum wire strands have low strength. When the conductor is subjected to tension, the strain of the fully annealed aluminum strands quickly enters the inelastic region of the stress-strain curve, and the aluminum strands undergo irreversible long-term deformation, with all the tension being transferred to the steel core.
