Partial discharge behaviour within two spherical cavities in a dielectric material

In high voltage insulation systems, a typical defect that exists is a void cavity. It is known that voids are a common source of partial discharge (PD) activity within an insulation system. Research on PD activities within a single void in an insulation material has been widely published. However, studies of PDs within insulation containing multiple voids have not been widely reported. Thus, a simulation model has been developed in this work to attain a better insight of PD events due to multiple voids. Two- and three-dimensional model geometries, which consist of two spherical voids, arranged in different positions with respect to the applied field direction in a dielectric material have been developed using finite element analysis (FEA) software. The models have been used to study the electric field distribution in the voids and PD inception voltage for different distances between the two voids, locations in the material and their respective sizes.