Dynamic formation mechanism of water droplet and induced surface discharges on silicone rubber composites

Wettability has become one of the most important factors influencing power equipment insulation system in coastal power grid, which can seriously threaten the safety of power grid. This paper aimed at numerical simulation and experimental investigation on dynamic formation mechanism of water droplet and induced surface discharges on silicone rubber composites under different AC voltages, considering the factors of surface tension and droplet volume. Obtained results reveal that the spreading coefficient increases with increasing the electric field intensity from 1 to 5 kV/cm and with increasing the droplet volume from 10 to 50 µL. The spreading coefficient shows a decreasing tendency when the surface tension increases from 29.3 to 61.0 mN/m. Moreover, the maximum of surface electric field shows an increasing tendency under the condition of increasing both the droplet volume and the surface tension. On the basis of the physical model of droplet deformation, the electric field force and the surface tension play a significant role in the process of droplet deformation. Meanwhile, the experimental results are consistent with the simulation analysis, reflecting that the droplet deformation and the induced surface discharges mainly depend on two parameters: the droplet volume and the magnitude of applied voltage