In this paper, a simplified transient thermal circuit model is proposed, and the error between the core temperature calculated by complete thermal circuit model and that by its simplified model are computed theoretically. Meanwhile, the finite element simulation model of cables is established to obtain the dynamic core temperature. Then the comparative analysis on the errors between the core temperatures calculated by the simplified model and the simulation temperatures. Analysis results show that the errors between the core temperatures calculated by simplified model and the simulation temperatures are inside the allowable range, thus in engineering application the simplified thermal circuit model can be used to calculate the core temperature of the cable by the outer sheath temperature.

XLPE cable; thermal circuit model; outer sheath temperature; dynamic core temperature; finite element simulation.