Simulation study on the influence of temperature change on streamers in transformer oil containing cellulose particles

The insulation integrity of oil-immersed transformers is pivotal for the reliable operation of high-voltage power transmission systems, wherein transformer oil serves the critical functions of insulation and heat dissipation. Variations in oil temperature are recognized as a significant factor influencing its dielectric performance. In this study, a two-dimensional axisymmetric plasma model with a rod-plate electrode configuration is established to investigate streamer propagation in transformer oil containing cellulose particles across a temperature range of 293–353 K. The simulation results indicate that cellulose particles exert a marginal influence on the later stages of streamer development, while the streamer propagation velocity increases significantly as the temperature rises from 293 to 353 K. Furthermore, rising temperature enhances both the peak electric field intensity and the peak electron density at the instant of breakdown. Conversely, at the intermediate propagation stage, temperature elevation suppresses the electric field intensity at the streamer head and the electron density within the streamer channel. Finally, this study conducts a statistical analysis of the space charge density at various propagation instants and elucidates the underlying mechanism of the aforementioned suppression effect by incorporating Poisson's equation. These findings enhance the understanding of the influence of oil temperature variations on streamer discharge and establish the theoretical foundations for temperature early warning strategies of the transformer system insulation.