About the correlation between the hydrophobicity and the impulse withstand voltage characteristics of insulation material surfaces under humidity conditions

Recent research indicates that the impulse withstand voltage characteristics of insulation material surfaces are influenced by the relative humidity in a greatly differing extent. This influence mainly depends on the physical and chemical surface structure of insulation materials. Apart from the impulse withstand voltage characteristics, the surface structure also influences the hydrophobicity of insulation material surfaces significantly. As earlier works have shown, measurements of the static contact angle are suitable in order to determine the hydrophobicity of insulation material surfaces. In this paper, the authors try to establish a correlation between the hydrophobicity and the impulse withstand voltage characteristics of different insulation material surfaces under humidity conditions. For this purpose, they describe the results of contact angle measurements and the results of impulse withstand voltage measurements, which have been performed on various insulation materials.