Effect of Total Gap Distance on Breakdown Voltage of Live-Line Work Air Gaps

During live-line work on transmission lines, the entry of linemen into the transmission line air gap constitutes a live-line work combined air gap. To improve the safety of linemen, research on the breakdown characteristics of a long air gap containing a floating electrode was carried out. The effect of different total gap distances on the discharge characteristics was studied through experiments in two types of gaps with an equal sum of sub-gap distances but different total gap distances. The result showed that among two types of gaps with an equal sum of sub-gap distances, if the total gap distances differed, there would also be differences in the breakdown voltage and the lowest breakdown voltage area (LBA). This phenomenon was explained by the formation mechanism of the LBA. Furthermore, the effect of different total gap distances on the potential distribution of sub-gaps was studied through finite element simulation analysis. This study is vital in ensuring personal safety during live-line work engineering.