Evaluation of field aged HMWPE insulated distribution cables

The evaluation of large quantities of field aged high molecular weight polyethylene (HMWPE) cables removed from the Pacific Gas & Electric Company system and subjected to extensive electrical and physical testing performed by the Hendrix Wire and Cable Company is described. The electrical tests conducted were AC and DC breakdowns, corona extinction and volume resistivity (VR). The physical tests included semiconducting shield adhesion. Microscopic studies were conducted for semiconducting shield protrusions, void and contamination count, and treeing. The results of the electrical and physical testing are reported. The correlation between AC breakdown strength (ACBD) and treeing is presented. Discussions also include comparisons of electrical characteristics of cables from wet and dry conduits. The data presented contribute to a better understanding of failure mechanisms and factors affecting cable life