Cables with voltage levels of 35kV and below are grounded at both ends because most of these cables are three core cables. In normal operation, the total current flowing through the three cores is zero, and there is basically no magnetic flux outside the aluminum or metal shielding layer. Therefore, there is basically no induced voltage at both ends of the aluminum or metal shielding layer, so there will be no induced current flowing through the aluminum or metal shielding layer after grounding at both ends.
Power cables are generally composed of wires, insulation layers, and protective layers, including single core, double core, and three core cables.
Single core refers to having only one conductor within an insulation layer. If it is to be used in a single-phase lighting circuit, two conductors need to be laid in parallel. Dual core refers to having two conductors within an insulation layer, which can be used in single-phase lighting circuits with only one conductor laid. (Wires can be divided into multi strand and single strand types, as well as soft core and hard core types. Selection is based on usage conditions and power consumption.)
