真空断路器真空度现场测量新技术

New Technology for Measurement of Internal Pressure of Vacuum Breakers

真空灭弧室真空度的传统测试方法主要有磁控放电法及工频耐压法。磁控放电法需要使用磁场线圈,而工频耐压法只能测出严重漏气的灭弧室。本文提出了一种新的真空度测量方法——发射电流起始场强法,该方法不需要施加磁场,它是将闭合的灭弧室触头强行拉开0.45mm,在触头间隙上施加工频高电压,接着使用电子轰击或间隙击穿的方法去除触头上固有的气体吸附层,再通过离子捕集的方法重建动态平衡的气体吸附层,然后测量发射电流起始场强Eip。通过理论分析知,发射电流起始场强Eip与真空灭弧室内的真空压强P成正比,故通过测量发射电流起始场强Eip的大小,就可以获得真空灭弧室内的真空度。本文在实验室对发射电流起始场强与真空度的关系进行了实验研究,结果表明,该新方法可将真空度测量范围拓宽到100～10-3Pa。

The traditional methods for measuring internal pressure of vacuum tubes of breakers are the magnetron and power frequency voltage withstand test. A magnet coil is needed by magnetron and only very bad tubes can be detected by voltage withstand test. In this paper, a new method--inception field Eip of emission current method, is presented for measuring internal pressure P of vacuum tubes, by which magnetic coil isn＇t need. Firstly vacuum gap 0.45mm is obtained by pulling the closed contacts, secondly power frequency voltage is applied on the gap and inherent gas adsorption layers are polished by electron bombardment or discharge current, finally the dynamic-balance gas adsorption layers are rebuilt again by ions capture and the Eip of gap is measured. It is known by theory analyses that the Eip is proportional to the P, so by detecting the value of Eip, the value of P can be obtained. The relationships between Eip and P is measured in laboratory, which is shown that the measuring ranges of P can be 10^0-10^-3Pa by this new method.