| Popis: |
Simulation analysis plays an important role in Systems Theory nowadays. In order to reveal the mechanism of space charge injection and generation in the process of liquid dielectric breakdown, the discharge of transformer oil between needle-plane electrodes under high electric field is studied. Based on the 2-D hydrodynamic model and Poisson equation of electric field, the system simulation model of oil discharge by different charge generation mechanism is established, based on which the inception and propagation process of discharge is simulated by COMSOL. By system simulation, the temporal and spatial distribution of the electric field intensity, space charge density, electric potential and temperature of transformer oil is obtained and deeply analyzed. The simulation results prove that the space charge generated by metal field emission and ionic disassociation are neither of the major factor for streamer formation in transformer oil, while the Zener molecular ionization and impact ionization are the major factors. Our research improves the understanding of the inception, propagation and breakdown process for discharge in transformer oil, and also the ionization mechanism in the liquid dielectric |
