Abstract:
Electric field enhancement due to the presence of
water droplets on the insulation surface is one of the main
factors reducing the flashover voltage of insulating
material. To increase the electrical performance of an
insulation system, the mechanisms of electric field
intensification are important to study. This article presents
the behavior of water droplets under a time-varying electric
field. Water droplets under different voltage levels, from 0
to 3 kV, and various electrical stress directions, vertical and
radial direction, were investigated. The deformation of
water droplets was described by a system of equations,
including Navier-Stokes equation and Poisson equation. In
order to determine the interface between water and air, the
level set method is chosen and applied to the models.
According to the calculated results, the direction of the
electric field has a significant effect on the deformation of
the water droplet. Additionally, this research reveals that
with higher input voltage, the degree of distortion is further
increased from the equilibrium state; the shape of water
droplet at zero-field. The field intensification of a deformed
droplet is comparable between two different directions of
electrical stress; vertical field and radial field respectively.
However, these values are lower when compared with the
results from a non-deformed droplet.
