The Effect of Air Bubbles on Streamer in Natural Ester Insulating Oils

Understanding pre-breakdown phenomena in natural ester insulating oil is crucial for ensuring the safe operation of electrical insulation systems. Based on Poisson equation and current continuity equation, a numerical model of natural ester insulating oil with air bubbles is constructed by introducing bubbles into the model. Finite element method was used to simulate the streamer discharge in natural ester insulating oil containing bubbles, and the influence of bubble size and number on the streamer branching behavior was analyzed. Simulating results show that the streamer path is dependent on the bubble size, especially the interface contact position between the bubble and the natural ester insulating oil.