This paper describes four different research activities with the common goal of gaining a better understanding of the degradation process of polymeric insulation materials so that their service life can be predicted. In the first strand of investigation, a new experimental setup was constructed to produce accelerated aging in dielectric samples by exploiting both partial surface discharges and internal discharges. In the second strand, a new floating grid computational technique has been introduced into simulation codes already developed by RSE, allowing internal gaseous defects to be represented in a much more flexible way.

This technique allows two different computational grids to be used to represent electrical components and internal defects. In the third strand, the possibility of simulating internal defects in resin-insulated transformers was successfully verified as a supporting activity for the development of new diagnostic systems dedicated to such components. Finally, in the fourth strand of investigation, the construction of a new experimental system capable of improving the diagnosis of internal defects in composite insulators under laboratory conditions was described. This activity aims to develop new diagnostic systems and algorithms for later use in the field.