Influence and mechanism analysis of acid or alkali damp environment on insulation performance of distribution cable accessories

The insulation performance of the cable accessories is critical to the safe operation of the power grid. The environment in which the distribution cables are laid affects the insulating properties of the cable accessories. In this paper, the artificial damp simulation experiments were conducted in different acidic and alkaline environments. The physicochemical and electrical properties of specimens were evaluated. The patterns and laws of volume resistivity, breakdown strength, and surface flashover behavior before and after etching were investigated. The results indicated that the resistivity of specimens declined gradually with the extent of etching time. After 28 days, the resistivity of XLPE etched in strong acid (pH = 1) and strong alkali (pH = 13) solutions dropped rapidly, and the SIR decreased by 34.2% (pH = 1) and 26.5% (pH = 13), respectively. The breakdown strength of the two specimens exhibited an overall trend of decline. The XLPE was reduced by 19.08% (strong acid), and 20.61% (strong alkali), respectively, and the SIR was reduced by 15.59% and 17.50% after 28 days compared to the untreated specimens. The flashover voltage of SIR is more severely reduced than that of XLPE. The patterns and principles of the influence of acidity and alkalinity and ion concentration on the electrical properties of the specimens were discussed based on the experimental results. The work has an important guideline for the moisture-proof material selection and damp fault analysis of the cable accessories.