In this study, a method for testing the aging of silicone rubber insulators using terahertz waves in the 0.17–0.22 THz frequency band is proposed, aiming at the problem of online non-destructive testing of the aging degree of composite insulators. The relationship between the aging degree of silicone rubber composite insulators and the relative dielectric constant was studied through first-principles calculations and molecular chain scission models. In addition, the electromagnetic model of the terahertz signal incident on the silicon rubber sheet was simulated and the relationship between the aging degree of the silicon rubber and the terahertz input return loss was obtained. Eleven insulator samples with different degrees of aging were selected. In these samples, the degree of aging was calibrated according to the degree of surface deterioration and the average partial discharge voltage. The terahertz return loss measurement experiment was performed after that. Finally, the results of experiment and calculation simulation were compared and the reliability of the relationship between the aging degree of the silicone rubber insulator and the terahertz input return loss was verified.

Aiming at the aging problem of insulating silicone rubber for new energy vehicles, this paper studies the equations of the aging of silicone rubber and its dielectric properties based on first-principles calculations. First, through the analysis of the microscopic mechanism of silicone rubber aging, the equations of the aging of silicone rubber and the rupture of the molecular main chain is obtained. Then the equations of silicone rubber molecular length and dielectric constant are solved by density functional theory. Ultimate, a molecular chain scission model of silicone rubber was built, and the micro-dielectric relationship was extended to the macroscopic level. The equation of the norm molecular length of silicone rubber and the dielectric constant is obtained. It provides an important theoretical basis for the aging detection of insulating silicone rubber for new energy vehicles based on electromagnetic waves.

Electric conductive silicon compounds are widely used and essential in electric power, energy and information industries. However, there are still problems such as insufficient stability of physical and chemical properties and weak electrical conductivity. To address the problem of low contact reliability of electrical joints in high-power transmission and distribution equipment, we assessed the influence of mechanically exfoliated graphene (MEG) content on the physicochemical properties of electrical joint compound (EJC). Varying amounts of few-layer MEG prepared with the conventional mechanically exfoliated method was added to the conductive silicon compounds, of which various physicochemical properties, such as penetration, drip point, volume resistivity and frictional properties were systematically assessed and compared with those with copper additive. We found that the addition of MEG effectively enhanced the temperature and mechanical stability of EJC and significantly reduced the material volume resistivity. This work paves the way to improve the key performance of electric conductive silicon compounds with advanced nanomaterials.