Numerical analysis of space charge accumulation and conduction properties in LDPE nanodielectrics

LDPE nanodielectrics show good space charge suppression performances, reducing the electric field distortions and improving the electric strengths. The decrease of space charge accumulation of LDPE nanodielectrics with increasing the nanoparticle loadings can be explained by the reduction of charge injection, the enhancement of conduction, and so on. However, the phenomena that the conductivities of LDPE nanodielectrics decrease firstly and then may increase with increasing the nanoparticle loadings has not been fully understood. A bipolar charge transport model consisting of charge injection, charge migration, and charge trapping, detrapping, recombination dynamics is used to investigate the space charge accumulation and conduction properties of LDPE nanodielectrics. Based on simulation results and existing experimental results, we discuss the influencing factors for space charge accumulation and conduction properties of LDPE nanodielectrics. It is found that the heightening of injection barrier plays a more important role in the suppression of space charges and the reduction of conductivities of LDPE nanodielectrics. Whereas, the variation of trap density and trap energy will regulate the nanoparticle loading dependent conduction properties.