Investigation of Discharge Propagation in Localized High-Temperature SF6 Gas With Breakdown Voltage Measurement

In high-voltage gas circuit breakers (HVCBs), high-pressure gas is blown between the electrodes to cool the arc. The temperature distribution between the electrodes at the current zero point has a large gas temperature difference. This study aims to experimentally clarify the effect of the cold gas region on the breakdown voltage of gases with large temperature differences. In an experiment, a hot gas generator using arc heat was used to create a gas space with a large temperature difference between electrodes, and the breakdown voltage was evaluated. The breakdown voltage in the gas space with a cold gas region was twice that of the case, where the space between the electrodes was filled with hot gas. It was found that the discharge initiated in the hot gas region was suppressed in the cold gas region and that the breakdown voltage in a gas space with the hot and cold region was influenced by the existence of the cold gas.