102 / 2022-03-13 10:45:44

Influence of Corona Aging on the Nonlinear Conductivity of Epoxy/SiC Nonlinear Composites

nonlinear resistive field grading material, SiC, corona aging, nonlinear conductivity

Purpose/Aim

Nonlinear resistive field grading material plays an important role in the electric field homogenization in the cable terminals and bushings due to its nonlinear conductivity. The electrical properties of the field grading material may be deteriorated as a result of electric or thermal field during its long service. So it is necessary to study the effect of aging on the electrical properties of the field grading material.

Experimental Details

In this paper, we aim to discuss the influence of corona aging on the field grading material. The 30 wt% epoxy/silicon carbide (SiC) micro-composite is prepared. The nonlinear conductivity, dielectric spectrum, breakdown strength and Fourier transform infrared spectroscopy (FTIR) of composite are measured, respectively.

Results and discussion

The results show that the nonlinear conductivity of composite is enhanced by corona aging. The relative permittivity decreases, whereas the loss tangent increases with the aging time. The breakdown strength increases first and then decreases. According to the FTIR, the degradation of the composite is mainly caused by the fracture of ether bond of epoxy matrix.