在运 252 kV真空断路器X射线辐射特性研究

To accurately determine the X-ray radiation characteristics of in-service high-voltage vacuum circuit breaker（VCB），in this paper the 252 kV single-break VCBs at Fangcun Substation in Guangzhou is taken as the research object and experimental investigations of its radiation characteristics are carried out. The thermoluminescent dosimeters（TLDs）are used to measure the radiation dose of the equipment during stepped withstand voltage tests across the break and under normal operating conditions with contacts closed for consecutive 15 days. Additionally， an array-type spectrometer based on the absorption method is used to reconstruct and analyze the X-ray energy spectrum generated during the withstanding voltage process. The experimental results show that during the step voltage withstand test，the radiation dose rates genersted by phases A，B，and C of VCBs at a distance of 1 m all exceed the standard limit specified in the GB 18871—2002《Basic Standards for Protection Against Ionizing Radiation Protection and for Safety of Radiation Source》. Among them，the radiation dose rate of phase C vacuum circuit breaker is more than seven times that of other two phases. The energy spectrum reconstruction results show that the peak of the radiation energy spectrum is located at approximately 70 keV. The photon energy is mainly concentrated in the range of 40～150 keV. During the 15-day continuous monitoring under normal operation，the VCBs in the closed position continuously generate X-ray radiation，with a radiation dose rate of approximately 0.5 μSv/min when normalized to a distance of 1 m.The dose rate exhibits a Gaussian decay as the angle between the measurement direction and the contact surface increases，reflecting the spatial non-uniform distribution of the radiation field. This study provides ref-erences for the radiation protection design of high-voltage VCBs.