板-板和球-球在CO_2气体内的放电特性  

Discharge Characteristics of CO_2 in the Plate-plate and Sphere-sphere Electrodes

作　　者：王欢[1] 汪泉[1] 项琼[1] 龙兆芝[1] 

机构地区：[1]中国电力科学研究院,武汉430074

出　　处：《高电压技术》2015年第6期2002-2007,共6页High Voltage Engineering

摘　　要：为了解CO2气体的绝缘特性,在相同的温度和湿度的条件下,对板-板电极和球-球电极在不同电极间距、不同压强下进行了工频耐压和雷电冲击试验。试验表明,体积分数99.99%的CO2气体绝缘强度随着电极间距和压强的增加而增加,符合经典气体的击穿曲线走势,证明了试验方法的正确性。在工频耐压试验中,当压强达到0.6MPa后,对CO2气体的绝缘特性有明显的改善。在雷电冲击试验中,0.5 MPa和0.6 MPa时气体的绝缘特性近似。此外,根据击穿曲线可知,均匀电场在雷电冲击试验中的极性效应不明显,而稍不均匀电场的极性效应非常明显;且负向冲击电压的击穿值远小于正向冲击电压击穿值,他们之间的击穿电压差随着间距的减小而减小。总结试验数据可推断,在110 k V设备中使用CO2气体作为绝缘气体时,其压强建议≥0.6 MPa。To obtain the insulation characteristics of CO2, we conducted power-frequency voltage withstanding tests and lightning-impulse voltage withstanding tests using CO2. In the tests, we used two types of electrodes, plate-plate and sphere-sphere, taking the electrode gap and gas pressure as the variables, and the ambient temperature and relative humid- ity were kept the same. The experimental results indicate that the insulation strength of CO2 （with volume fraction of 99.99%） increases with lengthening electrode gap and increasing gas pressure, which is consistent with the variation ten- dency described in classical breakdown theories. In the power-frequency tests, the insulation performance of CO2 is enhanced significantly when the gap pressure reaches 0.6 MPa. In the lightning impulse tests, the insulation characteris- tics of CO2 at 0.5 and 0.6 MPa are almost identical with each other. Moreover, according to the breakdown voltage waveform, minor polarity effect can be observed in the lightning impulse tests in uniform electric fields, whereas re- markable polarity effect can be observed for the quasi-uniform electrodes, specifically, the breakdown voltage of reverse impulse is far less than that of forward impulse, and the difference between the two reduces with shortening gap. Thereby, it is suggested that, for applications of CO2 insulation in 110 kV devices, the pressure of CO2 should be not less than 0.6 MPa.

关 键 词：CO2 放电特性 均匀电场 稍不均匀电场 工频耐压试验 雷电冲击试验 绝缘强度 

分 类 号：TM83[电气工程—高电压与绝缘技术]