Thermal Performance of Power Cables Installed in PVC Ducts Under Dynamic Loading

Abstract

Usually the load of the underground power cable varies throughout the day hours as well as with the year seasons. Consequently, the temperatures of the cable elements and the soil in contact with the cable surface change up and down. In some field applications the cables must be installed in non-metallic protective ducts. One of the merits of the cable installation inside duct is to save the cable from mechanical damage and to prevent human accidents. The goal of this article is to investigate the performance of the cables that are installed inside non-metallic ducts in case of dynamic loading conditions. Based on the heat balance of the cable thermal circuit nodes, IEC 60853–2 and IEC 60287standards proposed model in dynamic loading for cables that are installed in non-metallic protective tubes is constructed and used in the calculation of the cables' components and their surrounding soils temperatures. Extremely increase is noticed in the temperature of cable components in case of installing the cable inside protective duct. Considerable reduction in the temperature of the cable elements is observed when the cable is directly buried in the soil comparing with its installation in protective duct.