Microscopic Electric Field Modeling of Cable Accessory Interfaces

This study extends our previous work on simulation modeling of HVDC cable terminations and joints by focusing on the microscopic structure of the critical material interfaces in DC cable accessories. In this study, we present a simulation model that incorporates surface roughness and voids at the interfaces of high-voltage direct current (HVDC) cable accessories, specifically the interface between silicon rubber (SiR) stress cones and XLPE cable insulation. Previous models primarily focused on electrical-thermal coupled simulations and mechanical stress analysis but did not consider microscopic interface details. Using COMSOL's “image-to-curve” feature, we generated the model geometry from high-quality images, followed by manual refinement. The model was applied to simulate the electric field distribution and interface dielectric performance under varying interface pressures. Results demonstrate that increased contact pressure reduces cavity volume, creating regions with lower electric fields, which effectively improve insulation performance by hindering charge carrier movement. The study highlights the importance of interface pressure for optimizing HVDC cable accessory designs, while acknowledging that macroscopic models remain practical for accessory design.