CAJ | 학술논문

　　了解土壤的冲击特性是研究雷电流冲击下接地装置周围土壤火花放电现象的关键，同时也是输变电工程雷电防护的基础。通过试验研究了土壤水分含量、冲击极性等对土壤放电时延、50%冲击击穿电压和击穿场强的影响规律，并测试了不同水分含量下的土壤电阻率。试验结果表明：土壤电阻率随水分含量的增大而减小；放电时延随土壤水分含量的增大而减小；相同水分含量下，放电时延随击穿电压的增大而减小，随冲击电流波前时间的增大而增大，且负极性的放电时延比正极性大。而当土壤水分含量较低时，50%冲击击穿电压随着土壤水分含量的增大而减小，对应的击穿场强亦如此，且明显低于均匀空气击穿场强30 kV/cm，同时正极性50%冲击击穿电压比负极性低。
　　료해토양적충격특성시연구뇌전류충격하접지장치주위토양화화방전현상적관건，동시야시수변전공정뇌전방호적기출。통과시험연구료토양수분함량、충격겁성등대토양방전시연、50%충격격천전압화격천장강적영향규률，병측시료불동수분함량하적토양전조솔。시험결과표명：토양전조솔수수분함량적증대이감소；방전시연수토양수분함량적증대이감소；상동수분함량하，방전시연수격천전압적증대이감소，수충격전류파전시간적증대이증대，차부겁성적방전시연비정겁성대。이당토양수분함량교저시，50%충격격천전압수착토양수분함량적증대이감소，대응적격천장강역여차，차명현저우균균공기격천장강30 kV/cm，동시정겁성50%충격격천전압비부겁성저。
It is the key point to understand the impulse characteristics of soil for the research on spark discharge of the soil surrounding grounding device under the impact of lightning current, and is also the foundation of lightning protection for power transmission and transformation system. The influencing regularities of soil moisture content, impulse polarity etc. on delay discharging time, 50% impulse breakdown voltage and breakdown field-strength of soil are researched by experiments, and the soil resistivities under different soil moisture content are measured and tested. Experimental result show that soil resistivity decreases with the increase of soil moisture content; the delay discharging time decreases with the increase of soil moisture content;under the same soil moisture content, the delay discharging time decreases with the increase of breakdown voltage and increases with the increase of current wavefront duration and the delay discharging time under negative impulse polarity is longer than that under positive impulse polarity. Under lower soil moisture content the 50%impulse breakdown voltage decreases with the increase of soil moisture content, and so does corresponding breakdown field strength, which is evidently lower than 30 kV/cm, the breakdown field strength of air under standard temperature and pressure, and the breakdown voltage under positive impulse polarity is lower than that under negative impulse polarity.