SF6替代气体及其混合物在普冷温区的绝缘性能研究

Because of the high greenhouse effect index of SF6 gas, its future large-scale use is limited.And as the high liquefaction temperature,SF6 gas can not use in the special conditions for the refrigeration temperature range of -153℃～-30℃, researching the insulation characteristic of alternative gases and gas mixtures of SF6 gas in refrigeration temperature range of -153℃～-30℃ is presented. It is the expansion of research field and has important theory significance and practical value. Multiple gas mixtures composed by a variety of alternative gases and buffer gases are chosen as the research objectives. A temperature-controlled gas breakdown experiments platform will be built to measure the dielectric strength of mixture gases , then their insulating characteristic will be evaluated at different temperature ,the influence of temperature and un-equality degree of electric field to the insulating characteristic of the gas mixtures will be found out. The steady-state Townsend (SST) experimental method will be use to calculate the discharge parameters of the gas mixtures at the electronic pop stage at different temperature. Combined with the gas discharge theory, further explanation of the breakdown experiment results will be taken. The Boltzmann equation analysis method to calculate the gas discharge parameters in refrigeration temperature range of -153℃～-30℃ will be studied, it can complement the results of SST experiment. At last, combining with the greenhouse effect index and insulating characteristic, the suitable alternative gas mixtures of SF6 gas at different temperatures of the -153℃～-30℃ refrigeration temperature range will be evaluated.

SF6气体由于其很高的温室效应指数限制了其未来的大量使用，且液化温度较高，无法在-153℃～-30℃的普冷温区工作的特殊条件下使用，因而提出了在-153℃～-30℃的普冷温区研究SF6替代气体及其气体混合物的绝缘性能，对该领域研究外延的进行了拓展，具有重要理论意义和实用价值。选择使用多种替代气体和缓冲气体构成多元混合气体作为研究目标。搭建温度可调可控的气体击穿实验平台，测量不同温度下混合气体的耐电强度，评价其绝缘性能，找出温度、电场不均匀度对混合气体绝缘性能的影响；采用稳态汤生（SST）实验方法对不同温度下混合气体的电子崩阶段的放电参数进行测量，结合气体放电理论对击穿实验的结果做进一步地解释；采用Boltzmann方程分析法对-153℃～-30℃的普冷温区气体的放电参数进行计算，对SST实验结果进行补充。综合评定-153℃～-30℃的普冷温区不同温度下适用的SF6气体的替代混合气体。

SF6气体由于其很高的温室效应指数限制了其未来的大量使用，且液化温度较高，无法在-153℃～-30℃的普冷温区工作的特殊条件下使用，因而提出了在-153℃～-30℃的普冷温区研究SF6替代气体及其气体混合物的绝缘性能，对该领域研究外延的进行了拓展，具有重要理论意义和实用价值。本项目自行设计并建造了一套低温气体电气绝缘特性试验平台。通过对多种具有替代潜力的替代气体进行了露点温度计算，最终选用CF4作为主绝缘介质。为了进一步降低替代气体的温室效应指数，采用了CF4与N2进行混合替代。宏观电气试验研究表明，20%CF4/N2在普冷温区条件下具有良好的替代特性。通过玻尔兹曼方程对均匀场下CF4/N2混合气体的放电机理进行相关研究，获得了有效电离系数，相关碰撞反应速率，粒子迁移特性等参数。并通过comsol多物理场仿真软件，对放电通道发展情况进行了模拟，多角度论证了CF4/N2作为SF6替代气体在普冷温区环境下使用的可行性。