为研究极高海拔低气压下工频放电特性,搭建了包括真空试验腔、真空泵、真空计、工频电源、高速摄像机等仪器的低气压长间隙工频放电试验平台,并对其气密性和放电性能进行测试。该平台可实现23 Pa^100 k Pa范围内气压调节和600mm以内放...为研究极高海拔低气压下工频放电特性,搭建了包括真空试验腔、真空泵、真空计、工频电源、高速摄像机等仪器的低气压长间隙工频放电试验平台,并对其气密性和放电性能进行测试。该平台可实现23 Pa^100 k Pa范围内气压调节和600mm以内放电间隙调节。测试结果表明:试验平台能够模拟海拔20 km以上的长间隙工频放电,且对于试验周期较短的工频放电特性研究具有良好的气密性和放电性能。研究成果对高海拔低气压下长间隙放电特性研究具有重要参考价值。展开更多
为研究低气压下长间隙工频放电通道特性,利用低气压放电试验平台对600 mm棒-板间隙在5 k Pa、15 k Pa、25 k Pa、35 k Pa、45 k Pa、55 k Pa气压值下的工频放电通道特性进行了试验研究,得到了低气压条件对放电通道外形、通道偏移角度以...为研究低气压下长间隙工频放电通道特性,利用低气压放电试验平台对600 mm棒-板间隙在5 k Pa、15 k Pa、25 k Pa、35 k Pa、45 k Pa、55 k Pa气压值下的工频放电通道特性进行了试验研究,得到了低气压条件对放电通道外形、通道偏移角度以及通道起始前预放电过程的作用特点。研究结果表明:随气压升高空间电荷密度增大,在电子自由行程和碰撞几率的共同作用下放电通道逐渐收细、变亮,曲折和分叉特征逐渐明显;通道偏移角度逐渐减小;预放电过程由电晕变为刷状流注放电且预放电角逐渐减小。研究结果对研究低气压下长空气间隙放电特性提供参考。展开更多
为研究棒尖端外形对低气压下棒-板间隙直流放电特性的影响,利用低气压放电试验平台在2~20 k Pa气压下对锥尖头、半球头以及平头3种棒电极在100~300 mm间隙内进行直流电压放电试验,并通过仿真对不同棒尖端的放电特性试验结果进行验证。...为研究棒尖端外形对低气压下棒-板间隙直流放电特性的影响,利用低气压放电试验平台在2~20 k Pa气压下对锥尖头、半球头以及平头3种棒电极在100~300 mm间隙内进行直流电压放电试验,并通过仿真对不同棒尖端的放电特性试验结果进行验证。结果表明:棒尖端外形会对低气压下棒-板间隙的放电电压产生影响,击穿电压幅值从小到大依次为:锥尖头、半球头、平头;锥尖头棒和平头棒尖端存在局部电场极不均匀点,而半球头棒尖端电场分布较为均匀;随着气压的上升,棒-板间隙的U50%-P曲线呈稳定上升趋势。展开更多
为研究低气压下长间隙工频放电击穿电压与气压U_(50%)-P关系曲线饱和特性,利用低气压放电试验平台对2~70 k Pa气压范围内300~600 mm棒-板间隙进行了工频放电试验研究,得到不同间隙距离的U_(50%)-P曲线,并对曲线饱特性以及饱和区击穿前...为研究低气压下长间隙工频放电击穿电压与气压U_(50%)-P关系曲线饱和特性,利用低气压放电试验平台对2~70 k Pa气压范围内300~600 mm棒-板间隙进行了工频放电试验研究,得到不同间隙距离的U_(50%)-P曲线,并对曲线饱特性以及饱和区击穿前过程进行研究。研究结果表明:在2~70 k Pa气压范围内不同棒-板间隙的U_(50%)-P曲线均存在明显饱和区,随间隙距离减小饱和区向高气压方向移动,饱和范围增大且U_(50%)分散性增大。产生上述现象的的原因为:饱和区内击穿前间断发展的流注放电产生大量空间电荷,影响电子自由行程和碰撞几率,削弱了气压对电子自由行程和碰撞几率的影响。研究结果对研究低气压下长空气间隙放电特性提供参考。展开更多
为研究低气压下长空气间隙工频放电等离子体发展机理,利用低气压放电试验平台对4 k Pa下600 mm棒-板间隙进行了放电试验研究,得到该条件下等离子体发展特征并对其机理进行分析。研究结果表明:4 k Pa下棒电极下行等离子体发展的同时板电...为研究低气压下长空气间隙工频放电等离子体发展机理,利用低气压放电试验平台对4 k Pa下600 mm棒-板间隙进行了放电试验研究,得到该条件下等离子体发展特征并对其机理进行分析。研究结果表明:4 k Pa下棒电极下行等离子体发展的同时板电极出现电晕亮斑,板电极上行等离子体通道对周围放电的抑制作用较弱可同时发展多条等离子体通道,且等离子体通道自棒电极发展的速度较板电极大;间隙击穿后等离子体通道出现"飘弧"现象且在发展路径上具有选择性。研究结果为低气压下工频放电特性研究提供试验参考。展开更多
Common insulation gas cannot normally work in refrigeration temperature range(153-243 K), especially in extremely cold regions. To solve this problem, this essay uses cubic equation combined with two-parameter model i...Common insulation gas cannot normally work in refrigeration temperature range(153-243 K), especially in extremely cold regions. To solve this problem, this essay uses cubic equation combined with two-parameter model in theorem of corresponding states to estimate dew-point of hybrid gas. The influence of temperature on mixing ratio is studied by using van der Waals equation. The result shows that the mixing ratio is stable during temperature-fall period. Insulation property of CF_4 and CF_4/N_2 in refrigeration temperature range is studied through self-designed low-temperature test system. The result shows when the density of hybrid gas is invariable, temperature changing has less influence on breakdown voltage, and when the mixing ratio is 20%, CF_4/N_2 is the greatest potential hybrid gas.展开更多
The generation and propagation of a streamer is a significant physical process of air gap discharge. Research on the mechanism of streamers under low-pressure conditions is helpful for understanding the process of lon...The generation and propagation of a streamer is a significant physical process of air gap discharge. Research on the mechanism of streamers under low-pressure conditions is helpful for understanding the process of long-gap discharge in a high-altitude area. This paper describes laboratory investigations of streamer discharge under alternating current（AC） voltage in a low pressure test platform for a 60 cm rod–plane gap at 30 kPa, and analyzes the characteristics of streamer generation and propagation. The results show that the partial streamer and breakdown streamer all occur in the positive half-cycle of AC voltage near the peak voltage at 30 kPa. The partial streamer could cause the distortion of current and voltage waveform, and it appears as the branching characteristic at the initial stage. With the extension of the streamer, the branching and tortuosity phenomena become gradually obvious, but the branching is suppressed when the streamer crosses the gap. The low-pressure condition has little influence on the tortuosity length and the tortuosity number of the streamer, but affect the diameter of streamer obviously.展开更多
文摘为研究极高海拔低气压下工频放电特性,搭建了包括真空试验腔、真空泵、真空计、工频电源、高速摄像机等仪器的低气压长间隙工频放电试验平台,并对其气密性和放电性能进行测试。该平台可实现23 Pa^100 k Pa范围内气压调节和600mm以内放电间隙调节。测试结果表明:试验平台能够模拟海拔20 km以上的长间隙工频放电,且对于试验周期较短的工频放电特性研究具有良好的气密性和放电性能。研究成果对高海拔低气压下长间隙放电特性研究具有重要参考价值。
文摘为研究低气压下长间隙工频放电通道特性,利用低气压放电试验平台对600 mm棒-板间隙在5 k Pa、15 k Pa、25 k Pa、35 k Pa、45 k Pa、55 k Pa气压值下的工频放电通道特性进行了试验研究,得到了低气压条件对放电通道外形、通道偏移角度以及通道起始前预放电过程的作用特点。研究结果表明:随气压升高空间电荷密度增大,在电子自由行程和碰撞几率的共同作用下放电通道逐渐收细、变亮,曲折和分叉特征逐渐明显;通道偏移角度逐渐减小;预放电过程由电晕变为刷状流注放电且预放电角逐渐减小。研究结果对研究低气压下长空气间隙放电特性提供参考。
文摘为研究棒尖端外形对低气压下棒-板间隙直流放电特性的影响,利用低气压放电试验平台在2~20 k Pa气压下对锥尖头、半球头以及平头3种棒电极在100~300 mm间隙内进行直流电压放电试验,并通过仿真对不同棒尖端的放电特性试验结果进行验证。结果表明:棒尖端外形会对低气压下棒-板间隙的放电电压产生影响,击穿电压幅值从小到大依次为:锥尖头、半球头、平头;锥尖头棒和平头棒尖端存在局部电场极不均匀点,而半球头棒尖端电场分布较为均匀;随着气压的上升,棒-板间隙的U50%-P曲线呈稳定上升趋势。
文摘为研究低气压下长间隙工频放电击穿电压与气压U_(50%)-P关系曲线饱和特性,利用低气压放电试验平台对2~70 k Pa气压范围内300~600 mm棒-板间隙进行了工频放电试验研究,得到不同间隙距离的U_(50%)-P曲线,并对曲线饱特性以及饱和区击穿前过程进行研究。研究结果表明:在2~70 k Pa气压范围内不同棒-板间隙的U_(50%)-P曲线均存在明显饱和区,随间隙距离减小饱和区向高气压方向移动,饱和范围增大且U_(50%)分散性增大。产生上述现象的的原因为:饱和区内击穿前间断发展的流注放电产生大量空间电荷,影响电子自由行程和碰撞几率,削弱了气压对电子自由行程和碰撞几率的影响。研究结果对研究低气压下长空气间隙放电特性提供参考。
文摘为研究低气压下长空气间隙工频放电等离子体发展机理,利用低气压放电试验平台对4 k Pa下600 mm棒-板间隙进行了放电试验研究,得到该条件下等离子体发展特征并对其机理进行分析。研究结果表明:4 k Pa下棒电极下行等离子体发展的同时板电极出现电晕亮斑,板电极上行等离子体通道对周围放电的抑制作用较弱可同时发展多条等离子体通道,且等离子体通道自棒电极发展的速度较板电极大;间隙击穿后等离子体通道出现"飘弧"现象且在发展路径上具有选择性。研究结果为低气压下工频放电特性研究提供试验参考。
基金Project(51277063)supported by the National Natural Science Foundation of China
文摘Common insulation gas cannot normally work in refrigeration temperature range(153-243 K), especially in extremely cold regions. To solve this problem, this essay uses cubic equation combined with two-parameter model in theorem of corresponding states to estimate dew-point of hybrid gas. The influence of temperature on mixing ratio is studied by using van der Waals equation. The result shows that the mixing ratio is stable during temperature-fall period. Insulation property of CF_4 and CF_4/N_2 in refrigeration temperature range is studied through self-designed low-temperature test system. The result shows when the density of hybrid gas is invariable, temperature changing has less influence on breakdown voltage, and when the mixing ratio is 20%, CF_4/N_2 is the greatest potential hybrid gas.
基金supported by National Natural Science Foundation of China (Grant No.51277063)
文摘The generation and propagation of a streamer is a significant physical process of air gap discharge. Research on the mechanism of streamers under low-pressure conditions is helpful for understanding the process of long-gap discharge in a high-altitude area. This paper describes laboratory investigations of streamer discharge under alternating current（AC） voltage in a low pressure test platform for a 60 cm rod–plane gap at 30 kPa, and analyzes the characteristics of streamer generation and propagation. The results show that the partial streamer and breakdown streamer all occur in the positive half-cycle of AC voltage near the peak voltage at 30 kPa. The partial streamer could cause the distortion of current and voltage waveform, and it appears as the branching characteristic at the initial stage. With the extension of the streamer, the branching and tortuosity phenomena become gradually obvious, but the branching is suppressed when the streamer crosses the gap. The low-pressure condition has little influence on the tortuosity length and the tortuosity number of the streamer, but affect the diameter of streamer obviously.
