Measurement and simulation of PD in epoxy voids

Experimental data are presented of the development of PD activity in artificial air-filled spherical voids in epoxy resin over a period of ~6 months. The data are presented in the form of phase averaged plots of the charge distribution over the time (aging plots) and phase resolved histograms (PRPD patterns) at various aging states. They are interpreted by comparison to numerical simulations which are based on a physical discharge model. This provides insight into the physical changes in the void during aging. The simulation is the basis for a physically meaningful interpretation of the PD data. It provides rules for the identification of the defect type, the defect quantification, and an assessment of the aging stage