IEC 60104: Al-Mg-Si Alloy Overhead Conductors — Why AAAC Replaced Pure Aluminium

Overhead Line Conductors: Why Al-Mg-Si Alloy Replaced Pure Aluminium

IEC 60104 specifies aluminium-magnesium-silicon alloy overhead conductors (AAAC). Traditional ACSR uses a steel core for tension and aluminium strands for conduction. AAAC eliminates the steel core — the alloy provides both conductivity and strength, reducing weight by 15–20% with zero magnetic hysteresis loss (steel core hysteresis in AC magnetic fields causes additional line loss).

Key parameters: Conductivity ≥52.5% IACS (vs. ~61% for pure Al — a 14% conductivity trade-off for 2× tensile strength), tensile strength ≥295 MPa (~2× pure Al), and vibration fatigue resistance — Aeolian vibration at conductor-clamp interfaces is the primary cause of strand breakage in long-span overhead lines.

TN Lab — Overhead conductor material selection is a three-dimensional balance of conductivity, strength, and fatigue resistance.