Permittivity tomographic characterization of dielectric materials vs. partial discharge activity

The physical processes occurring during partial discharge (PD) in voids in solid dielectrics are complicated due to the lack of knowledge of void shape, location and gas pressure. Fast oscilloscopic techniques are so needed to measure the build up and decay of current as a function of time for single discharges. A new experimental approach resulting in tomographic characterization of the insulating material constituent of the specimen under test can be extremely useful for PD phenomena investigation. In this paper we propose a new approach capable to study the conditions for PD ignition. The proposed technique consists of tomographic reconstruction of the permittivity distribution