Enhancement of the thermal analysis of power cables installed in polyvinyl chloride (PVC) ducts under continuous and cyclic current loading conditions

Abstract

A study of the performance of power cables installed inside non-metallic ducts is presented here. Cable capacity calculations for this type of installation are done. The thermal analysis of cables inside ducts which are installed in air as riser or buried in soils is presented. According to IEC 60287 cables can be installed in fibre ducts in concrete layer surrounded by the soil, in this article it is proposed to install the cables in PVC ducts directly buried in the soil. Based on IEC 60287-1-3 and IEC 60853-2 standards proposed models in steady state and dynamic cable loadings are constructed. The proposed equivalent thermal models are used in the calculations of the cable components temperature for cables installed in ducts. It is concluded that very high increase in cable conductor temperature is observed when the cable is installed in duct and used as riser or even when it is installed in duct buried in soil. Significant decrease in the temperature of the cable conductor can be noticed when the cable is directly buried in the soil compared with that installed in ducts.