Accumulation of Space Charges in Epoxy Resin Nanodielectrics influenced by Poole-Frenkel Effect

Epoxy resin nanodielectrics own excellent electrical behaviors, such as the suppression of space charge accumulation, high resistance, high breakdown strength and so on. The application of epoxy resin nanodielectrics in insulating material of power equipment to reduce space charges and even electric field for long-term use has become a hot topic in recent years. The bipolar charge injection and transport model is adopted to investigate the distribution of space charges and the distortion of electric field in $200\boldsymbol{\mu}\mathbf{m}$ -thick epoxy resin nanodielectrics. It is found that as simulation time rises, more space charges accumulate and severer distortion of electric field can be observed in epoxy resin nanodielectrics. Then, space charge distribution at steady state indicate that Poole-Frenkel effect decreases the density of space charges near the interfaces between the sample and the electrode. Additionally, the influence of Poole-Frenkel effect under various electric field is studied. It is found that epoxy resin nanodielectrics with stronger Poole-Frenkel effect can maintain high resistance under low electric field and suppress the space charge accumulation under high electric field. Stronger Poole-Frenkel effect can enhance the nonlinear conductivity of epoxy resin nanodielectrics, which can reduce space charges and improve operation stability of power equipment.