丙烷喷射火焰中电极形状对间隙击穿特性的影响  

Effects of electrode shape on the gap breakdown characteristics in propane injection flames

作　　者：杨皓元 水凯 王振华 陈思怡[1] 尤飞 张云 YANG Haoyuan;SHUI Kai;WANG Zhenhua;CHEN Siyi;YOU Fei;ZHANG Yun(College of Safety Science and Engineering,Nanjing Technology University,Nanjing 211816,China;Anhui Conch Cement Co.,Ltd.,Wuhu 241000,China;Institute of Fire Science and Engineering,Nanjing Technology University,Nanjing 211816,China;China Southern Power Grid Extra High Voltage Power Transmission Company Wuzhou Branch,Wuzhou 543002,China)

机构地区：[1]南京工业大学安全科学与工程学院,南京211816 [2]安徽海螺水泥股份有限公司,芜湖241000 [3]南京工业大学火灾与消防工程研究所,南京211816 [4]中国南方电网超高压输电公司梧州局,梧州543002

出　　处：《清华大学学报（自然科学版）》2022年第6期1094-1101,共8页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金项目(51376089,50906039)。

摘　　要：高压输电导线作为输电系统的核心部分,一旦发生火灾将可能造成严重的后果。目前针对电极形状对输电线路间隙击穿的定性定量研究较少。该文利用30 kV·A/50 kV高压工频放电系统、丙烷喷射模拟火源以及棒/板2种不同形状电极,从击穿电压、击穿极性特征、击穿电弧特征3个方面研究了火焰条件下电极形状对间隙击穿特性的影响。研究发现,火焰条件下间隙距离小于8.0 cm时击穿波形具有“两期两点”特征,即击穿前“放电诱导期”、临界击穿时“间隙击穿点”、击穿产生电弧后“电弧导通期”、电弧阶段性消失时“击穿消失点”。通过设置不同间隙距离,测量不同电极组合的平均击穿电压和平均击穿场强,发现随间隙距离增大,棒-棒和棒(阴)-板(阳)电极击穿电压值增加速率分别为最低和最高。相较于空气间隙击穿,火焰条件下由于存在火焰流场和热浮力,间隙击穿具有更明显的极性特征,不同电极形状会影响正负周期形成导电通道的概率。击穿方向为正周期时,棒(阴)-板(阳)电极组合击穿概率最大,击穿方向为负周期时,棒(阳)-板(阴)电极组合击穿概率最大。研究结果表明:击穿电弧演变过程可分为导通阶段、燃烧阶段和熄灭阶段,火焰条件下电弧体积明显增大,向上漂移程度更剧烈,且火焰流场和热浮力会改变电极预设放电位置。该研究对山火防治以及山区高压电网的安全运行具有重要意义。High-voltage transmission wires, a key part of electrical transmission systems, can cause serious fires. There have been few studies of the effect of electrode shapes on gap breakdown around the transmission wires. This study analyzed the effect of electrode shapes on gap breakdown with ignition conditions in terms of the breakdown voltage, breakdown polarity and breakdown arc characteristics. The tests used a high voltage power frequency discharge system(type 30 kV·A/50 kV), propane injection as a simulated fire source and combinations of rod or plate electrodes. For gaps less than 8.0 cm with flames present, the breakdown waveform had a discharge induction stage, a gap breakdown point, an arc conduction stage and a breakdown vanishing point. The average breakdown voltages and the average breakdown field strengths of the various electrode combinations were measured by setting various gap sizes. The rod-rod electrode had the slowest increase of the breakdown voltage with increasing gap size while the rod(negative)-plate(positive) electrode had the fastest increase. The air gap breakdown had polarity characteristics due to the flame flow field and buoyancy. The different electrode shapes affected the probability of forming conductive channels with positive and negative periods. When the breakdown was during a positive period, the combination of negative rod and positive plate electrodes had the highest breakdown probability, while when the breakdown was during a negative period, the combination of positive rod and negative plate electrodes had the highest breakdown probability. The results show that the evolution of the breakdown arc can be divided into the conduction stage, the combustion stage and the extinction stage. A flame significantly increases the arc volume and the upward drift. The flame flow field and the buoyancy both change the electrode discharge position. This research is important for forest fire prevention and safe operation of high voltage power grids in mountainous regions.

关 键 词：输电线路 极性效应 丙烷喷射火焰 击穿电压 泄漏电流 放电电弧 

分 类 号：X932[环境科学与工程—安全科学]