Influence of structural characteristics on cable ampacity and electrical property for cross-linked polyethylene (XLPE) cable

The influence of structural characteristics on the cable ampacity and electrical property of the cross-linked polyethylene (XLPE) cable was presented in this paper. First, four HVAC XLPE cables were selected to detect the structural characteristics by Fourier transform infrared spectroscopy spectrum, gel content, differential scanning calorimetry, and x-ray diffraction measurements. Second, relevant structural parameters were extracted from the measurements. Subsequently, the cable ampacity and electrical property, serving as the macroscopic properties of the cable, were quantified by the measurement of thermal resistivity ρ and breakdown field strength E0. These two parameters reflect the behavior of thermal conduction and electrical conduction, respectively. Finally, the correlation between the structural characteristics and the macroscopic properties was established by linear regression fitting. The results show that the cable ampacity is deeply subjected to the integrity of the XLPE molecular chains and the proportion of secondary crystals within the XLPE. The electrical property is deeply dominated by the crystallinity and lamellar thickness of the primary crystals within the XLPE.