真空开关电弧形态演变实验与仿真研究

Real Time Imaging and Simulation of Appearance Variations in Vacuum Arc

真空开关电弧形态演变与其物理特性的变化密切相关,对开关能否成功开断电流有重要影响。本文首先建立了真空开关开断故障电流产生电弧的实验系统。然后利用CMOS高速相机采集电弧燃烧过程,并对电弧形态演变进行了较深入地定性分析。实验结果表明,燃弧过程中,真空电弧起始呈现集聚状态,包含桥柱电弧、扩散柱电弧和收缩柱电弧,电弧明亮,对触头烧蚀严重;在弧柱内高气压作用下,电弧转变为扩散状态,包含了亚音速和超音速电弧流动,电弧变暗,对触头烧蚀减轻;最终电弧随电流减小,开距增大而熄灭。最后利用电弧MHD模型仿真计算了电弧扩散阶段的光强变化,计算光强与电弧图像明亮度变化趋势吻合,可用于定量分析电弧形态变化。研究工作有助于提出电弧调控策略,从而成功开断大电流。

The time evolution of the are-discharge image in the vacuum circuit breaker（VCB）was characterized with the complementary metal oxide semiconductor camera of the lab-built measurement setup. The digitized images were pro- cessed and analyzed. The results show that the arc discharge image goes through three distinctive stages： i）The initial stage,where the arc in the aggregation state, and its images resemble the bridge-column arc, diffusion-column arc, and contracting-cohunn arc; moreover, the bright arc often ablates seriously the contacts;ii） The intermediate stage, where the increasing pressure inside the arc column turns the aggregation state into the diffusion state, including subsonic and super- sonic diffusions, accompanied with fading arc intensity and reducing contact ablation;iii） The quenching stage, where the decreasing current and increasing gap length quench the arc eventually. The time evolution of the arc intensity in the dif- fusion stage was simulated with the magneto-hydrodynamic model. The simulated results were found to agree reasonably well with the digitized arc images.