Simulation of Electric Field for Cavities in XLPE Medium Voltage Cable that Contribute to Partial Discharges

The presence of cavities in cross-linked polyethylene insulated cable is considered a weakness, may be potential sites for partial discharge, which eventually led to cable network failure. These cavities may create strong and inhomogeneous electrical field that usually produce partial discharges. In this paper, the experimental investigations of partial discharge magnitude measurements for cable samples with different size of artificial cavities are proposed. Leading to a better understand the results of experimental, this paper also analyses the electric field distributions within defected cables. In particular, a finite element model of defected cable samples is developed to study the electric field stress variation under artificial cavities using the COMSOL multiphasic, the effects of the cavity within the insulation before and during partial discharge are given. The experimental and the numerical results illustrate how the cavities can affect the electric field and the PD responses in XLPE insulted cables.