Investigation on the physical phenomena around current zero in HV gas blast breakers

An axially blown arc is studied under physical conditions typical of HV circuit breakers. The experiment is especially designed to produce a stable and reproducible arc with good accessability for diagnostics. After a stationary phase the current is ramped down with adjustable slope. The vicinity of current zero is especially investigated. For the first time, the most effective recovery zone is localized and its physical parameters are evaluated. The limiting curve for thermal reignition is determined. Based on the observed phenomena a theoretical description is derived which explains quite well the experimentally known extinction characteristics of this type of arc.