Algae Distribution on the HVDC Composite Insulator and the Influence of Algal Activity on Electrical Characteristics of Silicone Rubber

In warm and humid areas, algae are found on the surface of composite insulation materials, reducing their electrical performance. In this paper, the axial distribution of algae coverage and algae growth density on the HVDC insulator was analyzed based on digital image processing technology, and the reasons of the distribution were explored. Then algae were partially inactivated by high temperature, and the effect of algal activity on the electrical properties of silicone rubber was studied. The results showed that influenced by sunlight, rainfall, inorganic pollution and electric field, algae growth density decreased gradually from the low-voltage side to the high-voltage side, and algae coverage on the sheds near the high-voltage side and the low-voltage side was higher than that near the medium-voltage side. Algal growth significantly reduced the hydrophobicity of silicone rubber, and the death of algae was conducive to the recovery of hydrophobicity of silicone rubber and reduced the leakage current after wetting. However, despite the death of algae, the surface of silicone rubber could not return to the hydrophobic interface.