Open AccessRelaxation characteristics of ion jet formed across the short air gap in the cone–sphere electrode under positive polarity DC voltage
Author(s) -
Wang Ping,
Song Jingxuan,
Wang Xinyu,
Lü Fangcheng,
Geng Jianghai
Publication year - 2020
Publication title -
iet science, measurement and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.418
H-Index - 49
eISSN - 1751-8830
pISSN - 1751-8822
DOI - 10.1049/iet-smt.2019.0064
Subject(s) - rogowski coil , polarity symbols , schlieren , corona discharge , corona (planetary geology) , jet (fluid) , photoelectric effect , materials science , polarity (international relations) , air gap (plumbing) , optics , ion , relaxation (psychology) , atomic physics , electrode , voltage , current (fluid) , mechanics , breakdown voltage , physics , chemistry , optoelectronics , composite material , cell , biochemistry , astrobiology , venus , psychology , social psychology , quantum mechanics , thermodynamics
The research into the development of discharge under positive polarity voltage across the short air gap is of great significance to improve insulation of electrical equipment. By establishing a photoelectric joint detection system, this study observed phenomena in short air gaps before, and the period of breakdown. By utilising a photomultiplier tube and a Rogowski coil, the optical and current signals were obtained. Moreover, through z ‐type Schlieren system and high‐speed digital camera, relaxation images of ion jet formed across cone–sphere electrodes were obtained. Through comparison and analysis, the discharge of short air gap was divided into three stages: initial corona, strong corona and streamer breakdown. On the basis of this, the relationship between optical and current signals was compared by assessing characteristics of the ion jet in each stage. Also, the relaxation characteristics of an ion jet were analysed. The results showed that ion jets appeared in the initial corona stage, while relaxation channel of the ion jet was formed and the channel fluctuated in the strong corona stage. In the streamer breakdown stage, the process of expansion, constant fluctuation and breakdown appeared; the amplitudes of corona current signals and optical signals in these three stages constantly increased.