Insulators with Contaminated Surfaces, Part III: Modeling of Dry Zone Formation

A flat plate insulator with concentric electrodes and a fog guard is used to obtain the same qualitative behavior in leakage current and dry zone formation as a suspension insulator in a fog with horizontal wind for comparable levels of contamination and electric stress, thus demonstrating the importance of nonuniform wetting in this case. Attempts at mathematical description of the processes met with only qualitative success.