Study on the transference of hydroplibocity for Kaolin and Kieselgur

As two of the inert materials which were widely used in the artificial pollution test and recommended by IEC standard, Kaolin and Kieselgur were studied in the paper. The DC flashover voltage of porcelain insulators which was contaminated by Kaolin was much closed to Kieselgur, and the same as glass insulators. But the conclusion was quiet different for composite insulator. The flashover voltage of polymeric insulator contaminated by Kieselgur was larger about 14.7% than Kaolin under the same condition because of their significant difference of transfer characteristics. The reason of hydrophobicity migration difference of the two is revealed by scanning electron microscope (SEM), ASAP 2020 specific surface area and porosity analyzer, thermogravimetric analysis (TG), and Fourier Transform Infrared Spectrum (FTIR), respectively. The result shows that the hydroxyl (-OH) within Kaolin molecular is an important reason that cause hydrophobicity migration difference of Kieselgur and Kaolin, other than microphysics structure, specific surface area, total pore volume, average pore diameter. The result can be adopted to give theoretical reference to lay down rule of DC artificial pollution test for composite insulator.