Calculation of thermal fields of underground cable systems with consideration of structural steels constructed in a duct bank

Structural steels are used in underground cable systems to provide a high degree of mechanical protection for electrical cables. An accurate prediction of the temperature distribution of the system needs to include not only the effect of the total cable electrical losses but the eddy current losses induced in the steel. A finite element method is proposed to evaluate the losses generated in the conductors and in the steels, these are then used as the heat sources for thermal analysis. Several steel arrangements of a cable system are solved and compared. The results are useful for the design of a cable duct bank which uses structural steels.