Cable lines safety / 04.10.2024

Cable and pipe sparks

If the outer sheath of the cable is damaged, water can penetrate into the cable, and this will lead to the defects in the XLPE insulation, followed by its breakdown (that is cable will get a short circuit). Therefore, it is important to monitor the condition of the outer sheath of the cable, preventing the

Read More
Cable lines in ducts / 24.07.2024

High-voltage cable and HDPE pipe

Cable lines are increasingly laid not in the open ground, but in pipes (ducts). This allows you to protect cables from mechanical influences and aggressive environment, ensure quick replacement of the cable with a new one, lay cables not only by the traditional method in trenches, but also by horizontal directional drilling HDD (this method

Read More
Cable lines in ducts / 11.04.2024

Cable ducts can hide issues

All over the world, more and more cable lines are laid not in the ground, but in ducts (conduits, pipes). Such ducts are made of various materials (PE, HDPE, PE-RT, PP, PVC), they can be single-layer or multi-layer. But all these ducts have one common problem – they have “infinite” impedance Rd of the side

Read More
Cable lines in ducts / 28.03.2024

Long vertical cable pipe = good heater

Cable terminations are a weak element of the cable line, since:✅they have a complex structure;✅they are mounted manually (and the quality of installation depends on the qualification of the installer and his mood);✅they are subject to various external influences (sun, wind, rain, snow, ice etc). When a cable termination is damaged, it is not always

Read More
Cable lines in ducts / 26.12.2023

Bad cable protection on the ground level

The photos show the exit point of the high voltage single-core cable from the ground near the cable ternination. Please note that the cable is placed in a black single-layer corrugated pipe. What’s wrong here? 1️⃣ Corrugated pipe is not a reliable mechanical protection for high-voltage cable. For example, pay attention to the deep cuts

Read More
Cable lines in ducts / 21.10.2023

Laying cables in pipes (part 3)

Let’s explain how, using the system of correction coefficients given in cable catalogs, the influence of pipes on the long-term permissible current should be taken into account. The error in such calculations is actually due not only to the fact that the catalogs have lost the relevance of the correction factor Kp = 0.9. To

Read More
Cable lines in ducts / 21.10.2023

Laying cables in pipes (part 2)

Figure (A) shows the thermal scheme of a cable line laid in the ground. The following designations are used: Pc, Ps – loss of active power in the core and metallic screen of the cable; Tc, Ts, Tg – temperature of the core, screen, ground; Rins, Rosh, Rg – thermal resistances of insulation, outer sheath,

Read More
Cable lines in ducts / 21.10.2023

Laying cables in pipes (part 1)

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,

Read More
Cable lines in ducts / 21.10.2023

Do cable factories know everything about cables?

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.

Read More