Formation and Diffusion Characteristics of Carbon Black in Insulating Oil Under Multiple Breakdown

The particle size generation characteristics of carbon black particles during breakdown arc under AC voltage have important influence on insulation performance and repetitive breakdown voltage. In order to obtain the effect of arc energy after breakdown on the particle size generation and breakdown characteristics of carbon black particles, a carbon black particle test platform based on multi-parameter observation was built. The influence of oil gap distance and setting time on breakdown voltage was analyzed. The results show that the particle size of carbon black particles after breakdown of insulating oil is mainly between 5μm-50μm. With the increase of breakdown voltage, the arc energy increases, the carbon black particles increase and the proportion of carbon black particles increases. It is found that the larger the arc energy, the more favorable the formation of large particle size particles, and the stronger the trigger discharge ability of large particle size particles, which will lead to the obvious decrease of breakdown voltage in repetitive breakdown test. Increasing the setting time is helpful to the diffusion of carbon black particles and reduces the effect on breakdown voltage.