Effects of Mechanical Pressure on the Tangent Delta of MV Cable Joints

Medium-voltage cable joints are one of the critical components of the distribution networks. They represent the first cause of faults and outages. Among the others, partial discharge, dielectric, and temperature measurements are the typical tests performed for investigating over the early aging of such critical components. In this paper, a new study has been completed correlating the cable joint tangent delta (Tanδ) value to the external pressure applied on the insulating material surrounding the joint. Results confirm the presumed correlation. In fact, an increase of pressure results in a Tanδ decrease, hence in an extension of the cable joint working life.