X射线法评估灭弧室真空度的可能性研究

Evaluating Internal Pressure of Vacuum Interrupters with X-ray Measurement Method

笔者主要针对目前中压开关设备中使用非常广泛的真空灭弧室,研究其X射线吸收剂量率与真空度的关系,探讨以X射线吸收剂量率作为参量评估真空灭弧室的真空度的可能性。实验结果表明,经过电压老炼的真空灭弧室,在真空度低于10-2Pa时,也可能通过工频耐压试验,但其X射线发射的起始平均电场强度显著降低。因此X射线测量可与工频耐压试验配合进行,以检测出可通过耐压、但真空度已低于10-2Pa的灭弧室。

This paper focuses on vacuum interrupters which are widely applied in medium-voltage switchgears. The relationship between X-ray absorption ratio and internal pressure of a vacuum interrupter is analyzed in order to obtain a new method for evaluating the internal pressure by X-ray absorption ratio. Experimental result indicates that even though the internal pressure is lower than 10-2 Pa, the vacuum interrupter is possible to pass the power frequency voltage test, however the initial average electric field intensity of X-ray radiation gets lower significantly. Therefore, combining with power frequency voltage test, X-ray measurement method can be used to find out those vacuum interrupters that have passed power frequency voltage test but the internal pressure is lower than 10-2 Pa.