Steel Core Aluminum Stranded Wire Used in Overhead Conductors
Steel-cored aluminum stranded wire is a kind of special wire used for overhead transmission lines. It has the advantages of high conductivity, good thermal stability, low flexibility and good self-damping characteristics.
The transmission line is the necessary way to send electricity from the power generation end to the power receiving end, and the overhead transmission line occupies an extremely important position. The rapid development of electric power industry has also led to the continuous progress of overhead transmission line technology, constantly developing new types of conductors with high strength, high conductivity, heat resistance and low relaxation.
1. The steel core bears the mechanical load of the wire. The main contribution of the aluminum wire strand to the wire is to carry the current without carrying the mechanical load. Therefore, the operating temperature of the wire is not limited by the softening characteristics of the aluminum strand. The operating temperature is completely determined by the softening characteristics of the steel core, while the steel core has a higher recrystallization temperature and can maintain normal mechanical strength at a higher temperature.
2. ACSS/TW has a smaller diameter, which can reduce the ice and wind load of the wire. The smaller diameter and smoother outer surface can reduce the aerodynamic coefficient and reduce the damage of breeze vibration and galloping. With a larger aluminum cross-sectional area, it can increase the current carrying capacity and reduce the line loss, plus the smoother outer surface of the wire, which can reduce the level of corona and radio interference.
3. It has good anti-corrosion performance and thermal stability. The long-term operating temperature is up to 250 °C without reducing its mechanical strength. Under high temperature working conditions, its relaxation has no obvious change. It also has sub-damping characteristics, which is beneficial to reduce the breeze vibration and help to reduce the line loss of the transmission line.
4. It is a fully annealed aluminum. The electrical conductivity of soft aluminum is 63% IACS, and the mechanical strength is only 59-76 MPa, which is much lower than the ordinary aluminum wire mechanical strength (160-200 MPa).