Investigation of electric field enhancement and effects of discharge severity in an insulated power cable with multiple gaseous cavities

Gaseous cavities in the insulation of high voltage (HV) cables affect the electric field distribution and increase the electrical stress. This accelerates material ageing and creates partial discharge (PD) regions, which can cause cable failure. In this study, a simulation approach using a Finite Element Method (FEM) has been deployed to evaluate the discharge activity and electric field variation in cross-linked polyethylene (XLPE) insulated power cables. 2-Dimension models corresponding to sections of a practical three-core XLPE insulated cable were developed using COMSOL Multiphysics. Multiple cavities of different dimensions and configurations were considered. The results show that the electric field varies depending on the configuration and dimensions of the cavity. It was found that maximum field strength magnitude depends on the cavities, arrangement and location; an increase of up to 68.7% when compared to the case without cavities.