Thermal shrinkage tube is one of the most common insulating materials used in power cable industry. Copper and aluminium are the main conductor metals. Next, the properties of aluminium, which is the core material of XLPE cable, are introduced. Aluminum is one of the most commonly used metal materials in power cable conductor. Due to its abundant resources and low price, more and more aluminium is used. To replace copper as a conductor.
The resistivity of chemical pure aluminium is 0.0263x 10-6 m and the temperature coefficient of resistance is 0.004 031'. The parameters of aluminium materials with different properties are different, as shown in Table 2-9.
Table 2-9 Resistivity and Resistance Temperature Coefficient of Several Different Aluminum Lines
The aluminium ingots for conductors, sheath calendered wires and aluminium rods shall comply with YB813-55 and shall not be lower than the requirements of No. 1 aluminium and No. 1 aluminium (sheath) in GB 1196-75, as shown in Table 2-10.
In order to increase the softness of aluminium wires, aluminium wires used to make power cable cores are generally toughened like copper wires except for small cross sections (below 10 m), which are different from copper wires in that they do not need to be insulated from air, the toughening temperature (300 ^ 350 C) is low and the time is short. After toughening, the softness increases and the tensile strength decreases.