Investigation of space-charge build-up in materials for HVDC cable insulation in relationship with manufacturing, morphology and cross-linking by-products

Space charge accumulation in cross-linked polyethylene-based materials for high voltage direct current (HVDC) cable insulation is investigated. Samples molded from classical cross-linkable polyethylene pellets with and without nanoparticles are used. Curing conditions (160°C, 180°C and 200°C) and degassing are assessed in terms of morphology, cross-linking by-products and space charge accumulation under high dc field (50 kV/mm). The results are analyzed and cross-correlated in order to understand the observed space charge behaviors and to derive ways for optimizing materials and manufacturing processes.