The Effect Of Moisture On Insulator Surface In Highly Polluted Environments

In highly polluted environments, the salt, dust, and industrial particles deposited on the surface of material composite tension insulator, under humid conditions, form a thin liquid layer with moisture. This liquid layer reduces the surface resistivity of the material, making it easier for charges to flow along the surface. When the contaminant layer becomes damp, it absorbs moisture and soluble salts, producing an electrolyte solution, leading to a significant increase in surface leakage current and frequent discharge activity. The interaction between the humid environment and the contaminant layer is the basis for surface flashover accidents.

During surface flashover, the water film on the surface of high voltage transmission line insulators provides conditions for a conductive path, increasing the leakage current, enhancing the local electric field, and triggering arc discharge. The higher the soluble salt content in the contaminant layer, the more stable the conductive path formed with moisture, increasing the surface conductivity and leading to a decrease in flashover voltage.

Wet contamination also manifests in changes in surface properties during the performance degradation of overhead power line insulators. The combined action of contaminant particles and moisture can alter the surface energy of tension insulator materials, making materials that originally had some moisture resistance more easily covered and penetrated by water, which exacerbates the formation of conductive channels.