Arc Shape and Arc Temperature Measurements in SF6 High-Voltage Circuit Breakers Using a Transparent Nozzle

An investigation was performed to measure the arc temperature and arc shape in a SF6 circuit breaker (CB) during large current interruption. Experiments were conducted with a 126-kV SF6 CB. To measure the arc shape and the spatial distribution of the arc temperature effectively, the nozzle was replaced with a transparent organic glass material made from a polytetrafluoroethylene material. The arc shape variation was captured by a high-speed camera, and optical filters were installed on the camera in the case of overexposure. The arc temperature measurement was performed by obtaining the spectral line intensities of Cu I 510.5, Cu I 515.3, and Cu I 521.8 nm through a spectrograph, and the temperature was calculated by the two-line method. Measurements were performed during the entire operating process. The variations in the arc temperature with operating time were obtained. The established method was effective for measuring variations in the arc shape and temperature throughout the entire operating process.