Study of space-charge behavior in polyethylene for cable insulation by laser-induced-pressure-pulse technique

By utilizing the laser-induced-pressure-pulse technique, the combined effect of antioxidant and oxidation degradation was investigated. In LDPE with antioxidant, conduction current increases in the low oxidation region (α<3 cm^-1), and decreases in the high oxidation region (α>3 cm^-1) And as the degree of oxidation increases, remarkable homo space charge is formed. The introduction of the layer of degraded antioxidant on unoxidized PE enhances carrier injection into PE and leads to remarkable hetero space-charge formation. The introduction of the same layer on oxidized PE reduces carrier injection into PE and leads to small homo space-charge formation. These explain the dependence of the conduction and space-charge behavior on oxidation in LDPE with antioxidant