The surface of organic insulating materials such as room temperature vulcanized silicone rubber (RTV) coatings often has serious contamination deposition. In humid areas such as the Southwest region of China, algae contamination layers are present on the surface of the insulators. In this study, the geographical and creeping distribution of algae contamination on the surfaces of RTV insulators were studied by investigating and sampling various substations in the Southwest region. The main components of soluble salts in the contamination were studied by atomic absorption spectroscopy and ion chromatography. The algal genome was extracted by the cetyltrimethylammonium bromide method, and the species of algae and other microorganisms in the contamination layer were determined. The effects of algae or their secretions on the surface resistance and hydrophobicity were studied by quantitatively inoculating algae and smearing extracellular secretions on the RTV surface. The damage of the algae contamination layer to the microstructure of the silicone rubber was investigated by microscopic observation and thermogravimetric analysis. Results showed that the growth of algae was positively correlated with the surface contamination of RTV. The extracellular secretion of algae destroys the surface microstructure of RTV and causes the removal of alumina hydroxide, leading to the reduction of siloxane. Therefore, the resistance and hydrophobicity of the RTV surface were reduced. It is of great significance to study the characteristics and effects of the algae contamination layer for RTV maintenance.

In order to clarify the differences of partial arc propagation process and flashover process between uniform and un-uniform contaminated insulator strings, experiments of flashover characteristics on uniform and un-uniform contaminated insulator strings have been made in this paper. The result indicates that the partial arc initial voltage decrease with increasing ESDD in uniform contamination distribution situation, relatively, in situation of un-uniform contamination distribution, the initial voltage of partial arc not only relevant to ESDD of the whole insulator string, but also the distribution of pollution layer. In the context uniform contamination distribution, the partial arcs develop as progressive-style; and in the case of un-uniform contamination distribution, the propagating mode of partial arcs is progressive-style and leap-style alternating. Assume that ESDD value of the whole strings constant, the number and lightness of partial arcs would decrease with the reduction of ratio between upper and lower surface ESDD values, and Arc-over occurrence probability as well. High amplitude pulses of leakage circuit exist in the course of flashover duration.