These cables consist of a steel core in the form of one or more twisted steel wires, surrounded by one or more layers of hard aluminium wires EN AW-1350 or EN AW-1370. For protection against corrosion, core wires are covered with protective coating, usually in a form of a zinc layer applied galvanically. In addition, in order to prevent corrosion, if a cable may be exposed to the effects of atmospheric factors, spaces between wires are filled with special grease resistant to increased temperature. In operating steel and aluminium cables, mechanical load is transferred by both steel core wires and conductive aluminium layers. Hence, the strength of these cables while maintaining a sufficiently low weight allows for long distance suspension between pillars (even by a few kilometres), which in turn significantly reduces the number of necessary supporting structures.
Selected products safety data sheets:
AFL-1.7 (AL1-ST1A) cables based on PN-EN 50182 MT-19-01-16
AFL-6 (AL1-ST1A) cables based on PN-EN 50182 MT-19-01-16
AFL-8 (AL1-ST1A) cables based on PN-EN 50182 MT-19-01-16
A very interesting example of steel and aluminium cable with an optimised structure in terms of energy losses and carried out based on the standards of the Polish Energy Networks is a phase cable of 400 kV, with the mark of 408-AL1F_34-UHST PSE-SF.Line400kV.4PL-2013v2 MT-22-12-15. This cable consists of a core made of seven steel wires with extra high galvanised strength, on which three layers of hard aluminium wires are imposed, and the last layer is made of two previously released trapezoidal wires.