Investigation of current density, recombination rate and space charge density in polyethylene thin films based on bipolar charge transport model

Influence of Charge Injection on Dynamic Characteristics of Space Charge in Polymer Thin Films Under AC Stress

“…Charge carriers are injected from the cathode and anode, then transported through the dielectric thin film, and disappeared by recombination. The model consists of the following equations [2]:…”

“…Polyethylene is the commonly used dielectrics of DC and AC high voltage cables, for polyethylene exhibits higher reliability and lower dielectric losses than oil-impregnated paper insulation [1][2]. However, after long time running polyethylene will experience chemical and physical degradation.…”

Numerical study of the effects of AC voltage amplitude and frequency on space charge dynamics in polyethylene

“…The model includes the continuity, transport and the Poisson equation, which is based on bipolar injection from the electrodes, bipolar transport and recombination of positive and negative charges. The equations are of the form [2].…”

“…The time step Δ is selected according to the CFL condition, whose typical value is 2.0×10 -5 s. It is noted that the continuity equations are the convection diffusion equation, so numerical algorithm to solve the continuity equations is important for simulating space charge behaviors. Three-order flux limiter is applied to solve the continuity equations because it is proved that three-order flux limiter can restrain numerical diffusion and retain positivity when we simulated the space charge behaviors under DC electric field, which is described in detail in Ref [2]. Second order difference method is used to solve the Poisson equation.…”

“…Space charge accumulation and dissipation plays a significant role in dielectric material degradation [1][2][3][4]. In the past twenty years, many efforts are devoted to studying space charge characteristics when DC voltage is applied, but much less efforts are devoted to studying space charge dynamics when AC voltage is applied [5][6][7][8][9].…”