At present, overhead cables are mainly used for long-distance transmission of electricity. The traditional cable is aluminum conductor steel reinforced (ACSR). The steel core is used to bear the mechanical load caused by the weight of the cable. The aluminum stranded wire undertakes the power transmission task. Beginning in the 1990s, the carbon fiber composite core (aluminum conductor composite core, ACCC) cable using carbon fiber composite as the core rod of the cable has the following advantages compared with traditional wires:
(1) High strength and light weight. The tensile strength of ordinary steel wire is 1240~1410MPa, while the carbon fiber composite core rod of ACCC wire is twice that of the former, and its specific gravity is only 1/4 of steel. The unit length weight of ACCC wire of the same specification is lighter than that of conventional ACSR wire. 10%~20%, which allows the span of the overhead cable to be increased, reducing the number of towers by about 16%, while reducing the floor space.
(2) High conductivity and low power transmission loss. With the same outer diameter, the cross-sectional area of ACCC's aluminum stranded wire is 1.29 times that of conventional wires, so the current carrying capacity is increased by about 29%. Because the ACCC wire does not have the magnetic loss and resistance heating effect caused by the steel wire material, and it has a lower operating temperature under the same load condition, it can reduce the transmission loss by about 6%. At the same time, because ACCC uses trapezoidal aluminum wire, its appearance is smoother than ACSR's round aluminum wire, which improves the surface roughness coefficient, thereby increasing the corona onset voltage of the wire and reducing the corona loss.
(3) Low sag, reducing sag more than twice. Compared with conventional wires, ACCC wires have significant low sag characteristics. Under high temperature conditions, the sag is less than 12 of the steel core aluminum stranded wire, which can effectively reduce the insulation space corridors of overhead wires and improve the safety and safety of wire operation. reliability.
(4) Corrosion resistance. ACSR's aluminum wire and steel core are exposed to the air for a long time, and the surrounding environment will corrode the metal material, thereby reducing the strength of the wire and affecting the life of the wire. The carbon fiber composite core is not rusty and corrosion resistant, which overcomes the corrosion problem of the galvanized steel stranded wire core, and avoids the galvanic corrosion problem between the aluminum wire and the galvanized steel wire when the conductor is energized, which better solves the wire The aging problem of long-term operation, the service life is more than twice that of ordinary wires.