Study on the Characteristics of Dielectric Charge Transport in Polypropylene Cables

The performance of cables in HVDC transmission projects is directly related to the safe and stable operation of the entire system. As the main insulation material of cables, the space charge injection and accumulation characteristics of polypropylene under the action of DC voltage are important factors for the electrical breakdown of the insulation medium. This paper establishes a bipolar carrier simulation model of polypropylene material, and analyzes the influence of different parameters on the charge transport process. The simulation results show that with the increase of trap density, the electric field distribution inside the material has a similar change trend, but the charge migration speed gradually slows down; the decrease of the trapping coefficient and the increase of the detrapping coefficient will accelerate the migration of the charge; the temperature difference on the electrode The existence of, the charge injected on the high-temperature side becomes the dominant charge; when the polarity is reversed, the injection of electrons and holes at both ends of the medium is also reversed, and the degree of charge change increases with the increase of the voltage after the reversal.