Role of non-soluble contaminants on the flashover voltage of porcelain insulators

The influence of non-soluble or inert contaminants on the flashover voltage of HV outdoor porcelain insulators is examined. A dynamic arc model, presented earlier for predicting the flashover voltage of porcelain insulators covered with water soluble contaminants, has been modified suitably. The extended model has been used to predict the flashover voltage of suspension and station post insulators of various shapes for both ac and dc voltages. Good correlation with experimental data has been shown. The model can thus be used as a computer aided tool for design and maintenance of HV porcelain insulators.