Integrated Experimental and Simulation Investigation of Breakdown Voltage Characteristics Across Electrode Configurations in SF6 Circuit Breakers

This study investigates the breakdown voltage characteristics in SF6 circuit breakers, employing a novel approach that integrates both experimental investigations and finite element simulations. Utilizing a sphere-sphere electrode configuration, we meticulously measured the relationship between breakdown voltage and electrode gap distances ranging from 1 cm to 4.5 cm. Subsequent simulations, conducted using COMSOL Multiphysics, mirrored the experimental setup to validate the model's accuracy through a comparison of the breakdown voltage - electrode gap distance curves. The simulation results not only aligned closely with the experimental data but also allowed the extraction of detailed electric field strength, electric potential contours, and electric current flow curves at the breakdown voltage for gap distances extending from 1 to 4.5 cm. Extending the analysis, the study explored the electric field and potential distribution at a constant voltage of 72.5kV for gap distances between 1 to 10 cm, identifying the maximum electric field strength. A comprehensive comparison of five different electrode configurations (sphere-sphere, sphere-rod, sphere-plane, rod-plane, rod-rod) at 72.5kV and a gap distance of 1.84 cm underscored the significant influence of electrode geometry on the breakdown process. Moreover, the research contrasts the breakdown voltage in SF6 with that in air, emphasizing SF6's superior insulating properties. This investigation not only elucidates the intricate dynamics of electrical breakdown in SF6 circuit breakers but also contributes valuable insights into the optimal electrode configurations and the potential for alternative insulating gases, steering future advancements in high-voltage circuit breaker technology.