Separate measurement of conductive and pulsive components of leakage current of porcelain and polymeric materials for outdoor insulators

Leakage current and the resultant cumulative charge are important parameters to evaluate the insulation performance of polymeric insulating materials by the accelerated aging test. We define leakage current into conductive and pulsive components and measured them. For measurements of the pulsive component, we have developed a new computer aided discharge measurement system. Leakage current was measured separately with the change of electric field and conductivity of the salt fog so as to obtain the cumulative charge for porcelain as a reference sample. Measurement results indicate that this technique can quantitatively measure the pulsive component of the leakage current. We also investigated surface dryband formation of the sample