Reassessment of Polyethylene Power Cable

Despite a high volumetric co-efficient of thermal expansion, and relatively poor corona resistance, polyethylene power cables have given excellent service over the past 10 years at voltages through 15 kv. This good experience is largely a result of the use of a novel shielding technique which employs the use of a resilient semiconducting layer of material over the outer surface of the insulation. While cables without this shielding system are now in operation, laboratory cyclic-aging tests indicate that their life may be short if actually operated up to full thermal rating. Also, polyethylene melts at a relatively low temperature. This undesirable feature, of course, limits high-temperature operation.