Temperature Distribution in a Buried High Voltage XLPE Cable

Abstract

This paper presents a thermal analysis of a 245 kV AC XLPE cable system directly buried in the soil. The numerical computations of the cable temperature were performed using finite element method under Comsol Multi-physics environment. The effect of soil thermal conductivity on the cable temperature was investigated. The obtained results showed that the high voltage cable can operate in a moist soil with a current carrying capacity of 1022 A without risking deterioration, however in a dry soil, the temperature in the cable conductor is at the limit of malfunction and any other additional increase in heat will threaten the safe operation of the cable. Moreover, the cable temperature distribution was also investigated in desert regions characterized by very high ambient temperatures coupled with sandy soils of very bad thermal conductivity. It was found that the permissible conductor temperature is largely exceeded and if the current carrying capacity is not adjusted, the cable will overheat and its dielectric materials will be subjected to thermal aging which will greatly reduce the cable service life.