Control of the Thermal Environment of Buried Cable Systems [includes discussion]

When an underground cable line is installed in an area where the soil is a poor conductor of heat, it is necessary to take corrective measures so that the heat generated in the cable may be dissipated without overheating the cable. The most practical approach is to replace the soil in the immediate vicinity of the cable with a substitute soil of good thermal conductivity. Methods of mathematical analysis described in the literature in recent years may be utilized to determine what amount of soil must be replaced in this fashion. The replacement soil, of course, must be suitable economically as well as thermally. Tests have been conducted which show that silicic sands having a grain-size distribution which results in sufficiently high solids content are quite suitable for this purpose.