中文摘要：

对高电压真空灭弧室触头间长真空间隙（40mm及以上）的真空绝缘特性进行了讨论，包括击穿电压（直流电压，工频交流电压和标准雷电冲击电压）与触头开距的关系以及长真空间隙的老炼特性。目前对72／84kV级高电压真空灭弧室触头间隙范围（40mm及以上）的长真空间隙绝缘特性有了一定的了解，而126kV级高电压单断口真空灭弧室触头间长真空间隙范围（60mm及以上）的绝缘特性研究还有待深入开展。

英文摘要：

The vacuum insulation characteristics of a long gap （no less than 40 mm） between two contacts in high voltage vacuum interrupters （VIs） are discussed, including the relationship between breakdown voltage （DC voltage, power frequency voltage and lightning impulse voltage） and contact gap, and the conditioning characteristics of long contact gaps in vacuum. The vacuum insulation characteristics of the long gaps with the size of no less than 40 mm in 72/84 kV VIs are hence understood to a certain extent. However, the vacuum insulation characteristics of the long gaps with the size of no less than 60 mm in 126 kV single break VIs still need further investigating.