Cable lines - ampacity / 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

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Cable lines - ampacity / 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,

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Cable lines - ampacity / 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,

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Cable lines - ampacity / 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.

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