Study on the influence of transient flow of insulating gas in DC voltage measurement device

Abstract

The DC voltage measurement device is an important primary measurement equipment. In case of live refilling of SF6 under special operating conditions， it should be ensured that no DC system alarm or lockout will occur during the transient refilling due to sudden change of SF6 pressure. In this regard， an equivalent model of sealed gas paths of DC voltage measurement device is established. The transient flow characteristics of SF6 are simulated and comparatively analyzed by finite element method when the gas is refilled at different valve ports. It is found that the gauge pressure of SF6 varies greatly when refilled at the end of the tubular gas path， which easily leads to alarm or lockout in the DC system. By refilling tests at different valve port positions， it is verified that the pressure change is on the whole consistent with the simulation results. The study of transient flow pressure changes of SF6 during refilling at different valve ports is of significance to engineering guidance for the live refilling of the DC voltage measurement device.

Keywords

• dc voltage measurement device
• pressure
• insulating gas