Fabrication and Simulation of Nonlinear Resistive Field Grading Materials for Electric Field Tailoring of HVDC Cable Joint

In this study, the effect of nonlinear resistive field grading (NLRFG) materials on homogenizing electric field of HVDC cable joint is investigated by finite element method. Zinc Oxide (ZnO) nanofillers are dispersed in a silicone rubber (SR) matrix to fabricate NLRFG materials. Experiments are carried out to characterize the nonlinear resistivity of the fabricated composites, which are then imported in finite element analysis (FEA) models. Four different case studies are presented: i) where neat SR is used without field grading, ii) where neat SR is used with geometric field grading (GFM) iii) where NLRFG materials is used without GFM, and iv) where thin coating of NLRFG materials is incorporated without GFM. According to the results, coated NLRFG is the most effective approach, as it minimizes maximum electric stress in the triple points by 96.7% while introducing no substantial leakage power loss.