Simulation On Dielectric Properties Of Nonlinear Insulation Dielectrics Under AC Electric Field

Compared with the generalized dielectrics, the nonlinear insulation dielectrics, known as'Intelligent Insulation Materials', its conductivity or (and) the permittivity changed with external electric field. The performance of insulation structure was enhanced greatly for their wide application. For example, used in anti-corona structure of the generator bar end, the wrapping type terminals of distribution cable, extra high voltage DC Cable and ultra high voltage DC bushing. So, attention has been paid to research on the nonlinear insulation dielectrics, which the polymer filled with the inorganic semiconductor particles.Based on realizing ellipsoidal particle inorganic fillers random distribution within the polymer matrix with MATLAB and constructing finite element simulation models with COMSOL, this paper analysed dielectric properties of nonlinear insulation dielectric under AC voltage. Simulation models used by this paper were controllable, some controllable parameters included: edge length of the cube matrix region, the number of ellipsoidal particles, ellipsoidal particles size parameters (semiaxis a, b, c) and two spatial orientation angles of ellipsoidal particles. By simulation, this paper obtained the impact of the filler particle morphology parameters described above and the alternating voltage characteristics on the nonlinear insulation dielectric conductivity and permittivity.The study found: When the filler content gradually increased, the conductivity and its nonlinear coefficient increased, the permittivity also increased, The Curve ofε-E characteristics rose faster as the filler Content became larger; The three groups about the spatial orientation angle control: 0°/0°,0°/45°,0°/90°, as the particle orientation distribution was 0°/ 45°,the conductivity was the maximum and its nonlinear was obvious. With the increase of the angle, long semiaxis and XOY plane, the permittivity increased. The conductivity and permittivity that the particle orientation obeyed random distribution were higher than the orientation normal distribution; With the increase of the particle diameter ratio, nonlinear insulation dielectric conductivity and its nonlinear coefficient decreased, but the permittivity increased and the Curve ofε-E characteristics rose faster which the particle diameter ratio was great.If the frequency of the AC voltage was given, the higher amplitude, the greater AC equivalent conductivity and the permittivity, the conductivity and permittivity varied faster with the electric field; When the amplitude was given, with the increase of the frequency, the composite materials AC equivalent conductivity increased obviously, permittivity also increased, but both of their rate dropped.