Fundamental investigation technique on gas-blast arc behaviors in decaying and re-ignition processes using power semiconductors

This paper has proposed a new fundamental investigation technique on arc behaviors in decaying and re-ignition processes under gas flow condition. This technique utilizes power semiconductors like insulated-gate bipolar transistors (IGBTs) to control the arc current and voltage with a high accuracy in time domain. The free recovery condition was created by switching-on an IGBT connected in parallel with the arc device to investigate decaying process of the arc plasma under gas flow condition. Then, the quasi-transient recovery voltage (quasi-TRV) was intentionally applied between the electrodes in the arc device under the free recovery condition by turning-off the IGBT again, to study the re-ignition process of the arc plasma. At the same time, the arc behavior in a nozzle was observed by a high speed video camera at a frame rate of 200,000 fps. In the present work, arc behaviors in gas flow such as SF₆ and CO₂ in a nozzle was fundamentally investigated under free recovery condition and then after quasi-TRV application. In addition, the timing of the quasi-TRV application was changed to examine the recovery property of residual arcs in SF₆ and CO₂ gas flow. Through these experiments, the probability of arc successful interruptions were statistically measured for these gas flow arcs. These results provide fundamental data for comparison of the arc interruption capability of different conditions.