Effect of radiative and convective heat transfer on thermal transients in power cables

A model to study the thermal behaviour of a system of directly buried electrical power cables is presented. The model completely describes the conditions of heat transfer at the soil-air interface. In particular, the different incidences that the various radiative components have on the evolution of temperature in the system examined are evaluated. The method is applied to the case of a three-phase line placed under a daily cyclic load, based on experimental observations made on a line with cable of similar characteristics. Different evaluations are carried out assuming different characteristics for the soil and the climatic conditions