Prediction of steady state temperatures in a three-core distribution cable and splice

Abstract

A finite difference method is used to compute the temperatures in a 33 kV three-core cable and splice buried in the ground. The system is reduced to a two-dimensional field problem by replacing the three-core arrangement by a single-core cable of the same conductor section but with thicker insulation which gives the same conductor temperature. The assumptions made to achieve this are fully discussed. It is seen that the maximum temperature exists in the cable and not in the splice, and it may be concluded that for distribution cables of this general type the current rating may be established by consideration of the cable only.