Study on AC Breakdown Characteristics of Gas-Liquid Two-Phase Fluorocarbon in Phase Change Cooling Transformer

When the transformer uses fluorocarbon compounds for phase change cooling, bubbles will be generated in the gas-liquid two-phase medium, threatening the safe and reliable operation of the transformer. The discharging breakdown characteristics of gas-liquid two-phase dielectrics are closely related to the generation and aggregation of thermally induced bubbles. In this paper, a set of experimental equipment for measuring the breakdown voltage of gas-liquid two-phase dielectrics is designed and the related experiment is carried out. In this experiment, the experimental curve of dielectric breakdown voltage versus heat flux density is obtained. In addition, design recommendations for insulation margin of gas-liquid two-phase media in high-field-strength equipment applications are proposed to enhance reliability and performance.