XLPE Cable Insulation Resistance Modelling under Annealing and Thermal Ageing Effects

Cross-linked polyethylene (XLPE) insulated electrical cables are widely deployed for electricity transmission due to the reliable thermomechanical performance and excellent electrical dielectric properties of XLPE insulation. Insulation resistance (IR) is a common metric indicating the electrical condition of cable insulation that undergoes annealing and thermal ageing over its service life. Most research related to the IR simulation deals with either the thermal ageing process of XLPE insulation itself or the annealing process of XLPE insulation by considering the diffusion of chemical specifies from semicon layers. This paper develops a discretisation IR model to estimate the temperature distribution across the XLPE insulation layer and simulate the IR drop under the thermal ageing effect or the U-shape variation of IR under the joint effects of annealing and thermal ageing, respectively. The IR simulation results are discussed around the necessity of combining annealing and thermal ageing effects for IR simulation with the presence of semicon layers.