Nanofilled nonlinear coating material for improving proactive flashover performance of high voltage insulators

Flashover is a common reason of insulator failures especially in contaminated areas like industrial and coastal regions. In this paper, a nanosized carbon black is used to control the current-voltage (I-V) characteristics of a proposed coating material to improve proactive flashover performance which is presented by reducing the dry band arcing as well as the surface current over insulator. Using finite element analysis, the electric field distribution on polluted insulation samples is investigated to clarify the importance of nonlinear hydrophobic coated insulator. Experiments on glass slaps coated with the proposed material at different nanosized carbon black loadings are carried out to determine I-V characteristics of a proposed coating material. Accordingly, a theoretical model of I-V characteristics is introduced. Then, modeling of the dry band arcing voltage is presented and experimentally verified. Finally, surface current is experimentally measured for proposed coating applied on real field insulators. The results provide evidence of the improved performance of the coated insulators.