Remarkable modification of transferring characteristics for both positive and negative charges in XLPE-PS composite

Insulating materials with excellent performance have been one of the key factors that keep the safe operation of high-voltage direct-current (HVDC) cable systems, and investigating their charge trap distribution characteristics is of great significance to improve electrical properties, such as reducing conductivity, suppressing space charge accumulation, and elevating breakdown strength. In this paper, surface potential decay processes of low-density polyethylene (LDPE), low-density polyethylene/polystyrene (LDPE/PS), crosslinked polyethylene-polystyrene (XLPE-PS) and crosslinked polyethylene (XLPE) were investigated, and migration properties of positive charges and negative charges as well as related charge trap characteristics were analyzed. The results demon- strate that for positive charges and negative charges, the formation of featured structure in XLPE-PS composites reduces carrier mobility and deepens charge trap depth but does not change the width of charge trap energy distribution, which remains 0.27eV. Compared with XLPE, XLPE-PS shows a more unified trap distribution under positive and negative polarity, which may be attributed to the featured structure. The findings are helpful to clarify the relationship between multi-phase structure and electrical insulation performance of XLPE, and to provide a reference for the design of insulating materials for extruded HVDC cables.

Automated summary

Investigating charge trap distribution characteristics of insulating materials is important for improving electrical properties, and this study focused on the surface potential decay processes of LDPE, LDPE/PS, XLPE-PS, and XLPE. The results showed that the featured structure in XLPE-PS composites reduced carrier mobility and deepened charge trap depth, without changing the width of charge trap energy distribution. Compared to XLPE, XLPE-PS exhibited a more consistent trap distribution under both positive and negative polarities, possibly due to the featured structure. These findings provide insights into the relationship between multi-phase structure and electrical insulation performance, and offer guidance for the design of insulating materials for HVDC cables.