Partial discharge phenomena within an artificial void in cable insulation geometry: experimental validation and simulation

In the presence of void in cable insulation, repetition of partial discharge (PD) occurrences is one of the main sources of insulation degradation, which may lead to complete breakdown. Therefore, it is important to monitor the condition of cable insulation through PD measurement. Replicating PD measurement on a test object with the presence of a void within cable insulation may help a better understanding of PD characteristics within cable insulation to be achieved. Therefore, in this work, test samples of cable insulation geometry containing an artificial void were prepared in the laboratory for PD experiment. The PD measurements were done as a function of void size and applied voltage. A physical model of PD activities within an artificial void in cable insulation geometry was also designed using finite element analysis method. The model was developed by considering PD occurrences within non-uniform electric field distribution in the void and charge movement along the void surface. The model was applied for simulation of PDs within the void in cable insulation geometry to increase the understanding on PD physical phenomena. This includes the impact of distribution of void surface charge on the distribution of the electric field within the void through comparison with the captured measurement results.