Finite element models of the application of stress-relieving dielectrics

The addition of ferroelectric fillers to a polymer can produce a material with electric field-dependent permittivity properties, which can be used for the purposes of electrical stress relief for applications under AC fields. The paper illustrates the electrical stress-relieving properties of these composite polymers through finite element models. The electric field-dependent permittivity characteristics of the stress-relieving dielectric have been based on a barium titanate filler in an acrylic resin, for a range of filler levels. Two sets of models are considered. The first set of models considers the case of a needle-point plane geometry and the electrical stress distribution in the stress-relieving dielectric for needles of different geometries. The second set of models considers the stress distribution in a coaxial cable using the stress-relieving dielectric. The effectiveness of the stress-relieving dielectric in each of these geometries is clearly illustrated