Effect of water droplets and water films on the electrical performance of practical outdoor insulators

Presence of water droplets over the insulator surface enhances the electric field intensity and leads to electrical breakdown. Water droplets/films lead to the breakdown of the insulator even under the absence of actual contaminants. The objective of this work is to study the effect of water droplets/films in causing an electrical breakdown on practical insulator at various levels of hydrophobicity. This is done by investigating the electric field distribution around the water droplets/films on a model insulator for the shed and sheath configurations by varying the material of the insulator and the contact angles. Effect of deterioration of the hydrophobicity on field distribution is investigated through placing multiple droplets/films on the sheath and shed regions of practical insulator configurations. The results of our simulations and their practical implications are discussed.