摘要
研究SF6气体放电过程中微观粒子的动力学特性,可以得到临界击穿场强等衡量气体绝缘能力的宏观参量,这些宏观参量对高压开关设备的设计和研发有重要作用.为此,根据流注理论建立了反映气体放电过程中微观粒子动力学特性的流体动力学模型,将有限单元法与通量校正传输法相结合,求解均匀电场下极间隙为0.5 cm时SF6气体的放电特性,得到了放电过程中带电粒子的动力学行为以及空间电荷对电场的影响.通过循环计算均匀电场中不同电压下SF6气体的放电过程,得到其临界击穿场强.在此基础上,计算不同压强下SF6气体的临界击穿场强,通过与已有的均匀电场中SF6气体临界击穿场强实验值进行对比,验证计算结果的准确性,并分析气体压强对SF6气体击穿特性的影响.计算结果表明：当压强为0.1 MPa时,极间距为0.5 cm的SF6气体在39 kV的外电压下发生击穿,间隙内的电场在6.8 ns时开始发生畸变,此时电子数密度最大值达到2.7＆#215;1017 m-3,随后SF6由绝缘状态发展为导电状态;当气体压强为0.1～0.4 MPa时,SF6的临界击穿场强与气体压强基本呈线性关系.数值计算结果与实验值基本相符,验证了其正确性.
Through studying the dynamic properties of micro particles in SF6 gas discharge, we can obtain some macroparameters like critical breakdown field strength, which are indexes for evaluating gas insulation. These macro parametersplay an important role in designing and developing high voltage switchgears. Thus, we established a hydrodynamic modelby using the steamer theory to depict the dynamic properties of micro particles in gas discharge. On the basis of the modeland combining the finite element method with the flux corrected transport method, we calculated some characteristics ofSF6 gas discharge in 0.5 cm gap in tmiform electric field, and analyzed the dynamic behavior of charged particles and theinfluence of space charges on electric field in the discharge process. Meanwhile, the critical breakdown field strength ofSF6 in uniform electric field was calculated through loop calculations of discharges under various applied voltages.Moreover, the critical breakdown field strength under various pressures was computed. The results were verified throughcomparing with existing experimental data, and the effect of pressure on the breakdown properties in SF6 was discussed.The results show that when the pressure is 0.1 MPa, SF6 breakdown happens when the voltage between 0.5 cm spacedelectrodes is 39 kV. 6.8 ns after applying the voltage, the electric field in the gap starts to distort, and the electron numberdensity reaches 2.7x10^17 m3 at this moment. Then SF6 gas changes from insulation state to conduction state. When pres-sure varies from 0.1 MPa to 0.4 MPa, the critical breakdown field strength of SF6 is generally linear to pressure, which isin accordance with experimental data.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2014年第10期3046-3053,共8页
High Voltage Engineering
基金
国家自然科学基金(51277123)
国家电网公司科技项目(GY17201200063)~~
