Influence of algal fouling on hydrophobicity and leakage current on silicone rubber

Polymer insulators made of silicone rubber (SIRs) can suffer from algal fouling in tropical and even temperate regions. The purpose of the present study was to understand the hydrophobic behavior and leakage current characteristics of algal-fouled SIR materials when exposed to wet and contaminated conditions. Salt-fog tests were conducted on SIR samples colonized with the treatable alga Chlorella vulgaris. SIR samples covered with non-soluble kaolin powder at a deposition density comparable to that for the alga-treated SIRs were also evaluated. Results show that algal fouling considerably reduced the SIR hydrophobicity compared to the kaolin powder, which resulted in the development of a large leakage current. A major component of the leakage current produced on algal-fouled SIR is dry-band discharge, which leads to material degradation involving tracking and erosion.