What are the main technical performances of overhead cables?
High-voltage overhead cable insulation, in addition to meeting the higher electrical performance requirements, but also requires good weather resistance, in order to long-term exposure to sunlight safely work. Existing overhead cable insulation material is made of polymer insulation and a certain amount of carbon black blend.
When the overhead cable is used, because the earth voltage is not entirely added to the cable insulation, the air to the ground is mostly borne by the air medium. Therefore, the insulation performance of overhead cable is higher, and it is obviously better than the general ordinary oil paper and XLPE cable.
Inside and outside the semi-conductive shield
1KV low-voltage overhead cable, due to the low electric field strength of the conductor surface, do not need to use the inner semi-conductive shielding layer. When the overhead cable approaches the grounding body, the electric field strength of the 10kV overhead cable conductor surface is 2 ~ 3kV / mm and the electric field strength of the 35kV overhead cable conductor surface can be as high as 5kV / mm, which means that the inner semiconducting layer must be used.