Development of insulation material for DC cables-space charge properties of metallocene catalyzed polyethylene

Applicability of polyethylene polymerized using a metallocene catalyst to an insulation material for DC power cables has been investigated. The accumulation properties of space charge in a range from room temperature to 90°C was examined using the pulse electroacoustic method. The result indicated that hetero-charge was observed in the vicinity of the surface of a sample at increased temperature, and that hetero-space charge produced by activation of an antioxidant added to the sample was increased or decreased with the increase of the temperature of the sample. A hetero-charge absorber was added for controlling the hetero-space charge. As a result, hetero-charge was not observed on the sample in a high electric field extending from room temperature to high temperature. It was confirmed that the volume resistivity of the sample was increased at high temperature