Performance of reduced wall EPR insulated medium voltage power cables. I. Electrical characteristics

Paper insulated lead covered cables (PILC) have had a long and successful heritage. After almost 100 years, this design of cable is still in operation and continues to be manufactured. However, utilities are now looking for a reliable replacement for PILC cables. This is due to two primary reasons 1) difficulty in installing and maintaining this type of cable and 2) increasing pressure to replace these cables due to environmental concerns. To date diameter limitations of conventional extruded dielectric cables has impeded their replacement in existing PILC conduits. This paper describes a study for the evaluation for reliably reducing the insulation thickness to achieve a lower diameter cable to effectively replace PILC cable in existing conduits. Part I of the investigation reviews the theory of insulation wall determination and the test program carried out to evaluate electrical performance of reduced wall EPR cables. Additionally, cable design concepts and constructions are discussed. In Part 11 the mechanical performance on conventional and reduced wall EPR insulated cables are evaluated. This is reported in a separate paper