Surface Morphology Effects of Semi-conductive Layers on Interfacial Electric Field and Charge Injection in HVDC Cable Insulation

This paper presents a systematic investigation of carbon black (CB) morphology effects on interfacial electrical properties in HVDC cable insulation systems. Through a combined experimental and simulation approach employing atomic force microscopy (AFM), finite element method (FEM) modeling, and space charge measurements, we quantitatively analyze the influence of three key morphological parameters: particle size, concentration, and protruding depth distribution. The results demonstrate that increasing CB particle size significantly reduces local electric field enhancement due to decreased surface curvature effects. Furthermore, optimal CB concentration is found to balance field uniformity with dispersion quality, while samples with uniform protruding depth exhibit lower charge injection compared to heterogeneous counterparts. The strong correlation between morphological characteristics and electrical performance metrics validates the proposed evaluation framework. These findings provide concrete material design guidelines for developing high-performance semi-conductive shielding layers, offering solutions to critical space charge challenges in next-generation HVDC cable systems.