| Bare overhead lines come in several types according to structure and composition. All must strike a balance between mechanical resistance (strength) and electrical resistance (conductivity). Aluminium conductors steel reinforced (ACSR) offer high-strength and allow high-voltages in large span runs. Corrosion-free all aluminium alloy conductors (AAAC) are ideal for severe conditions. New technologies such as AERO-Z� allow for an equal diameter, a greater useful cross-sectional area, and therefore an increased transport capacity; or for a smaller diameter, almost the same transport capacity. Nexans, France, provides bare overhead conductors that offer low corrosion, various alloys adapted to each country's norms, high-transmission capacity for dense grids and various sizes according to customers' needs.
AERO-Z� conductors, developed by a Belgian subsidiary of Nexans, is a significant breakthrough in overhead technology. These "smooth" and compact conductors are made up of Z-shaped profiled wires in aluminium or alloy of aluminium, which overlap each other so as to form an almost cylindrical outer surface, ribbed with helical grooves. This smooth surface reduces the amount of snow and frost accretions. Unlike traditional stranded conductors which risk oscillatory instability (such as complex galloping effect at great range, even in mild winds), AERO-Z� conductors can withstand aeolian vibrations through better damping characteristics. They also drastically reduce the drag coefficient. Since they are more compact than stranded cables, they can also carry a much higher current in the same diameter. The Z-shaped solution is also being applied to optical ground cables (OPGW-Z), and a new generation of AERO-Z�-HC will deliver high-conductivity.
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