Fundamental Studies of Gas Insulation Breakdown Processes Using Optical Emission Spectroscopy

Summary

In order to clarify the mechanism of discharge characteristics in dry air, we have developed a spectroscopic method that can directly measure the electric field strength in the discharge. In this work, by using this spectroscopic method and observing streak records of the light emitted by the discharge, we investigated the characteristics of positive streamer discharges in needle-to-plane electrodes in 0.1 - 0.5 MPa (absolute pressure) dry air. The streak records of discharges showed that, as the gas pressure increased, the lengths and the duration times of both the primary streamer and the secondary streamer became short. The electric fields in the discharges were estimated by the ratio of emission intensities both of the second positive system band of molecular nitrogen and of the first negative system band of molecular nitrogen ions, which were obtained by spectroscopy. The results showed that the reduced electric fields obtained were close to the simulation results performed by other authors in the past. When the gas pressure was small, the reduced electric field at the tip of the needle electrode was small. This was considered to be the result of the generation of the secondary streamer, which had a lower reduced electric field than the primary streamer. This result was also consistent with the results of the streak records.

Additional informations

Authors

Tang , Rozga Pawel, Stanek Marcin, Yi Yong, Zhang Chuyan, Wang Yuanjiu, Wang Liming, Kikuchi Yusuke, Nagata Masayoshi