For materials, the low voltage cables can use copper or aluminum for the conductor, high voltage cable copper conductor is more, in addition to the overhead lines (steel core aluminum stranded wire, etc.);
From the conductor cross-sectional area, because the high voltage cable on the carrying capacity is larger, so the nominal cross-section conductor is often compared to big (but not necessarily, conductor cross-section of low pressure is very big also, mainly the use of occasions to decide).
On the shape of it, in addition to the reasons for low voltage cable, sometimes to save costs, can be made abnormity of conductor, such as tile shape, fan, semicircle, but the high voltage cable often makes it round conductor, to facilitate heat dissipation (or split conductors circular, reduce skin effect).
Low voltage power cables and low-voltage overhead lines, low-voltage overhead insulated lines compared to the higher cost, are more difficult to lay and maintain.
However, because it has the characteristics of reliable operation, no pole, does not occupy the ground, is less affected by the outside world, etc., it is widely used in low-voltage distribution systems.
Voltage levels above 1kV to 750KV are collectively called high-voltage cables.
The main use is the power sector for the transmission of electricity and voltage conversion.
Generally used for long-distance transmission of electricity, substations voltage level change.
We commonly used voltage levels below 220KV.
Long-distance transmission of electricity voltage level are ultra-high voltage, the power sector designated special power workers construction, special maintenance.
High-voltage cables are conductors - inner semiconductor layer - insulation layer - outer semiconductor layer - metal armor - sheath layer from the inside to the outside.
Low-voltage cables are conductor-insulation-steel ribbon-sheath from inside to outside.
Many low-voltage cables do not have a steel belt.
The main difference between hv and lv cables is that high-voltage cables have more semiconductor layers and shielding layers than low-voltage cables.
Therefore, high-voltage cables than low-voltage cable insulation layers are much thicker, and the structure is more complex, the process requirements are also high.