X-Ray Radiation in 126-kV Vacuum Interrupters During Sequential Power–Frequency Conditioning and Comparative Analysis of Conditioning Methods

The pursuit of high-voltage, ecofriendly vacuum circuit breakers (VCBs) as alternatives to SF₆-insulated apparatus brings to the fore the challenge of X-ray radiation generated during the conditioning of vacuum interrupters (VIs). This article presents an experimental and simulation study on the X-ray emission characteristics of a 126-kV VI. The temporal evolution of radiation during sequential power–frequency voltage conditioning cycles is investigated, and the effectiveness of three conditioning methods is comparatively evaluated from a radiation perspective. A self-designed absorption spectrometer was employed to measure the X-ray dose and spectrum. Results from five consecutive conditioning experiments revealed a progressive reduction in the total X-ray dose alongside significant spectral hardening, indicating a saturation of the conditioning effect after 4–5 cycles. Comparative analysis demonstrates that, while laser preconditioning has a minimal impact (~5% dose reduction), high-current preconditioning substantially reduces the subsequent power–frequency conditioning dose rate by approximately 35% compared to the conventional method. Crucially, high-current conditioning also results in a softer X-ray spectrum, characterized by a lower proportion of high-energy photons, which implies reduced penetration capability and a lower radiation threat. These findings provide insights for optimizing conditioning protocols, enhancing personnel safety, and guiding the design of radiation shielding for high-voltage VI testing and manufacturing.