To investigate the interface polarization characteristic of nonlinear composite insulation structure

taking a linear / nonlinear composite material with the plate electrode structure as a research object

we simulated the distribution of charge and the electric field in two-layer dielectric under step voltage and polarity reversal voltage with different amplitudes. The simulation results show that

under the condition of the time constants of two-layer dielectric intersection

interface charges decrease with the increase of amplitude of step voltage. When the applied voltage is increased to the critical voltage that time constants of two-layer dielectric intersect

the polarity of interface charges will reverse. Then interface charges increase with the increase of the voltage amplitude. And the polarization is quikened and the depolarization gets slower with the increase of the voltage amplitude. The maximum instantaneous interfacial charge and electric field in two-layer dielectric under polarity reversal voltage are both higher than those under the step voltage. The results reveal that the accumulation of charge is improved by nonlinear dielectric with field enhanced conductivity. But in the moment of voltage polarity reversal

the reliability of insulation system may be decreased due to the high field strength in the nonlinear dielectric.