中文摘要：

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，而工频耐压法只能检出严重漏气的灭弧室。该文使用微放电起始电压Ud与发射电流起始电压Uc之比Ud/Uc量灭弧室的真空度。该方法不需要施加磁场，而是使用下述方法进行测量：将闭合的灭弧室触头强行拉开0．2-0．3mm，然后在触头间隙上施加工频高电压，利用间隙微放电电流对触头表面进行老练，以除去触头表面原有的吸附层，最后再测量间隙的微放电起始电压Ud与发射电流起始电压Uc。理论研究表明，真空灭弧室内的真空压强P越小，Ud／Uc越大，故通过测量Ud/Uc的大小，就可以获得真空灭弧室内的真空度。文中在实验室的真空比对系统上对不同管型灭弧室的Ud、Uc、Ud／Uc与真空压强P的关系进行了测试，测试结果表明，该文提出的Ud／Uc法，其真空度测最范围能达到10^0-10^-3Pa。

英文摘要：

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 picked out by voltage withstand test. A new method the ratio of inception voltage Ud of micro-discharge to inception voltage Uc of emission current can be used to measure internal pressure P of vacuum tubes. By this method, internal pressure of vacuum tubes can be measured without using magnetic coil, but with following process： firstly, vacuum gap 0.2-0.3 mm is obtained by forced pulling the closed contacts, secondly, power frequency voltage is applied to the gap and inherent gas adsorption layers are polished by micro-discharge current, finally, the Ud and Ue of the vacuum gap is measured. Theoretical study shows that the bigger Ud/Uc is, the smaller p is. So by measuring the value of Ud/Uc, the value of p can be obtained. The relationships of Ud, Uc, Ud/Uc with p are measured in laboratory, the test results show that the measuring ranges of p can be 10^0-10^-3 Pa by this new method.