Parameters influencing the behavior of water droplets immersed in dielectric liquids submitted to electric stress

This paper is aimed at the analysis of the dynamics of water droplets immersed in dielectric liquids submitted to a uniform electric field up to breakdown. The influence of the sizes, position and concentration (number along the electrode axis) of water droplets with respect to the electrodes on their deformation and breakdown of oil gap is investigated. It is shown that the deformation can be symmetric or asymmetric depending on the surface charge density, the electrode gap, the positions, sizes and concentration of water droplets within this gap, the applied electric field and its application time. The conditions required to bridge the liquid gap are also discussed. It is also shown that even if the sizes of water droplets are insufficient to bridge the gap when elongated, local vaporization and discharges can be initiated at their poles and lead to breakdown.