Space charge behavior in multi-layered dielectrics with LDPE and LDPE/MgO nanocomposites

Space charge distributions were investigated in multi-layered dielectric films consisting of combinations of low-density polyethylene (LDPE) and its nanocomposite (NC) with MgO nano-fillers during application of a dc electric field of 100 kV/mm at room temperature and 50°C. At 100 kV/mm, a packet-like charge appears in LDPE, but not in NC. Similar behavior is also observed in multi-layered samples. These phenomena are explained by assuming that the nano-fillers effectively suppress the increase in conductivity induced by the high electric field, which agrees well with related work done previously by the authors.