Dry Band Formation around Underground Cable

Abstract

The current ratings of underground power distribution cables are affected by ambient temperature, cable laying depth, number of cables in parallel circuits, sheath bonding and thermal resistivity of soil. One important factor usually ignored is the formation of dry zones around the underground power cables. Dry zones are usually formed around underground cables when they are loaded due to the migration of soil moisture content. This in turn may cause an abrupt rise in temperature of the cable sheath, leading to thermal damage of cable insulation or reduces the insulation life time.