Cableizer ®

Thermal resistance, equivalent

Equivalent thermal resistance per conductor.

Symbol
$T_{eq}$
Unit
K.m/W
Formulas
$T_{1}+n_{ph} \left(\left(1+\lambda_{1}\right) T_{2}+\left(1+\lambda_{1}+\lambda_{2}+\lambda_{3}\right) T_{3}\right)+n_{cc} \left(\left(1+\lambda_{1}+\lambda_{2}+\lambda_{3}\right) \left(T_{4i}+T_{4ii}+v_{4} T_{4\mu}\right)+\lambda_{4} \left(\frac{T_{4ii}}{2}+v_{4} T_{4\mu}\right)\right)$cable
$T_{1}+n_{ph} \left(1+\lambda_{1}\right) T_{prot}+n_{cc} \left(1+\lambda_{1}\right) \left(T_{4i}+T_{4ii}+v_{4} T_{4\mu}\right)$PAC/GIL
$T_{hs}+T_{4iii}$heat source
$T_{fo}+T_{4iii}$fiber optic cable
Related
$\lambda_{1}$
Loss factor shield (screen/sheath)
$\lambda_{2}$
Loss factor armour
$\lambda_{3}$
Loss factor steel pipe pipe-type cable
$\lambda_{4}$
Loss factor magnetic duct
$n_{cc}$
Number of conductors combined
$n_{ph}$
Number of phases in a cable
$T_{1}$
Thermal resistance conductor—sheath [K.m/W]
$T_{2}$
Thermal resistance armour bedding [K.m/W]
$T_{3}$
Thermal resistance jacket [K.m/W]
$T_{4i}$
Thermal resistance medium in the duct [K.m/W]
$T_{4ii}$
Thermal resistance duct wall [K.m/W]
$T_{4iii}$
Thermal resistance ambient [K.m/W]
$T_{4\mu}$
Thermal resistance ambient [K.m/W]
$T_{fo}$
Thermal resistance FOC [K.m/W]
$T_{hs}$
Thermal resistance heat source [K.m/W]
$T_{prot}$
Thermal resistance protective cover [K.m/W]
$v_{4}$
Ratio thermal resistivity dry/moist soil
Used in
$\gamma_{X}$
Attenuation factor for crossing [1/m]