The Current Carrying Capacity of Power Cables in Tunnels

The capital costs incurred in the provision of power circuits through underground tunnels is such as to make further efforts in the refinement of thermal rating computations worth while. In the present work steady state and transient temperature calculations are performed via thermal network models of the system. Heat transfer by radiation is separately accounted for and heat transfer by free or forced convection determined by means of new empirical formulae established experimentally on groups of cables.