Electric power industry consulting
Laying cables in pipes is a common way of laying high-voltage cable lines. Usually, pipes are accounted for using a correction factor K=0.9, that is, it is assumed that laying cables in pipes reduces the permissible current by 10%. For example, if the cable line in the ground had a permissible current of 1000 A,
In the cable catalogs of leading manufacturers of power cables there is a system of correction coefficients for selecting the core cross-section. According to this system, laying cables in pipes reduces the long-term permissible current (current capacity) of the cable line, and the corresponding correction factor is 0.9. I must say that this is incorrect.
In recent years, the laying of high-voltage cable lines is often carried out in polymer pipes. Such pipes are laid either at the bottom of the trench or are dragged into the ground into channels prepared by horizontal directional drilling (HDD). Laying of cable lines in pipes provides mechanical protection of cables, minimizes open excavation