Space Charge Modeling in Polymers: Review of External Applied Constraints Effects

The purpose of this work is to describe, with numerical simulation, the space charge behavior in polymeric materials. Particular intent is accorded to the variation of the thermo-electrical constraints. The simulation is performed for a range of the electric field from 10 to 110 MV/m and the space charge behavior was described at various temperatures: 0, 27, 60 and 100 degrees C. In general, the numerical results show a predominance of the temperature effect, vs. the electric field, on the space charge behavior. The dynamic of the electrical charges is different under 100 degrees C, a forehead is observed on their distribution in the sample. Strong electric field enhancements are remarked in the dielectric, they exceed 38% of the applied field under 100 degrees C. Only 1.3% of augmentations are observed under room temperature even with higher applied field of 110 MV/m. Both experimental and theoretical Current-Field characteristics, plotted in log-log scale, show linear behavior with slopes greater than one. The different values of slope indicate space charge limited conduction; a change is remarked at 40 MV/m which can defines the beginning of the high fields regime in the case of the studied polymer (Polyethylene Naphthalate).