Open AccessStreamer‐to‐precursor transition in N 2 –SF 6 mixtures under positive repetitive submicrosecond pulses
Author(s) -
Zhao Zheng,
Dai Zhifeng,
Sun Anbang,
Li Jiangtao
Publication year - 2022
Publication title -
high voltage
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.732
H-Index - 20
ISSN - 2397-7264
DOI - 10.1049/hve2.12119
Subject(s) - streamer discharge , pulse (music) , pulse repetition frequency , electric field , atomic physics , materials science , sulfur hexafluoride , analytical chemistry (journal) , chemistry , optics , physics , chromatography , telecommunications , radar , organic chemistry , quantum mechanics , detector , computer science
The evolution of discharge dynamics in N 2 –SF 6 mixtures under long‐term repetitive submicrosecond pulses is investigated based on pulse‐sequence resolved electrical and optical diagnostics. The effects of gas pressure, pulse repetition frequency (PRF), and SF 6 concentration on discharge evolutions are determined. The number of applied pulses before breakdown is shown to non‐linearly decrease with increasing PRF for all included gas pressures and SF 6 concentrations. A higher SF 6 concentration is favourable for increasing relative insulation capability under repetitive pulses. Unexpected complexities of discharge evolutions under repetitive pulses are reported for the first time for the discharge mechanism transition when a strong electronegative gas is introduced. A pulse‐to‐pulse progressive streamer (first discharge)‐to‐precursor (before breakdown) transition is observed in an N 2 –SF 6 mixture under positive repetitive pulses and is less dependent on gas pressure than traditional scenarios. The formation of a precursor section is jointly supported by electrical and optical signatures. The discharge mechanism transition and the detour phenomenon under repetitive pulses are discussed based on the effects of space charges on the spatial distribution of the electric field strength.