According to voltage level:
Power cables can be classified into medium and low voltage cables (35 kV and below), high voltage cables (above 110 kV), ultra-high voltage cables (275–800 kV), and extra-high voltage cables (1000 kV and above). They can also be classified by current system into AC cables and DC cables.
According to insulation material:
Oil-impregnated paper insulated power cables: Power cables with oil-impregnated paper insulation. They have the longest history of application. They are safe, reliable, have a long service life, and are inexpensive. The main disadvantage is that their installation is limited by elevation differences. Since the development of non-drip impregnated paper insulation, the elevation difference limitation problem has been solved, allowing oil-impregnated paper insulated cables to continue to be widely used.
Plastic insulated power cables: Power cables with extruded plastic insulation. Commonly used plastics include polyvinyl chloride, polyethylene, and cross-linked polyethylene. Plastic cables have a simple structure, are easy to manufacture and process, are lightweight, and are easy to lay and install, without being limited by elevation differences. Therefore, they are widely used as medium and low voltage cables and are trending towards replacing viscous impregnated paper cables. Its biggest drawback is the presence of dendritic breakdown, which limits its use at higher voltages.
Rubber-insulated power cables: The insulation layer is made of rubber with various additives, which is thoroughly mixed and extruded onto the conductive core, then vulcanized at high temperature. It is soft and elastic, suitable for applications with frequent movement and small bending radii.