Growth Characteristics of <scp>XLPE</scp> Cable Electric and Water Mixture Under Different <scp>pH</scp> Levels

ABSTRACT In order to explore the influence of the pH value of the solution on the growth characteristics of the electro‐hydro hybrid tree of XLPE cable, the XLPE cable was aged by building electro‐hydro mixed tree platforms with different pH values. The growth characteristics of XLPE cable electro‐hydro mixed tree under different pH values were observed and analyzed by macroscopic dielectric property test and microscopic morphology detection. Macroscopic tests on cables aged under different acidity and alkalinity conditions revealed that the aging degree of cables is more severe in acidic or alkaline environments. When there are electrical tree defects in the insulation, acidic or alkaline solutions with different pH values promote the accelerated aging of mixed trees, and the acidic environment has a more significant effect on the accelerated aging. Then, the microscopic detection of sample sections with different acidity and alkalinity was carried out to analyze the growth of branch defects. It was found that both acidic and alkaline environments could accelerate the growth of mixed branches. On the basis of electrical branches, a strong acid and strong alkali environment was more suitable for the growth of mixed branches than a weak acid and weak alkali environment, and the promotion effect of acidic solution was more obvious. At the same time, the transformation mechanism of electrical tree to water tree in the cable under different pH conditions was analyzed. Finally, the correlation between the dielectric performance parameters and the branch density of different groups of samples is analyzed. The fitting model of the branch density on the macroscopic dielectric performance parameters is obtained by curve fitting, which provides a non‐destructive testing method for multi‐branch aging of cables.