基于汤逊放电的C_(4)F_(7)N/CO_(2)摩尔分数检测

Molar Ratio Detection for C_(4)F_(7)N/CO_(2) Mixed Gas Based on Townsend Discharge

C_(4)F_(7)N/CO_(2)混合气体作为一种新型环保绝缘气体应用在实际设备中时,检测混合气体的混合比例是保证设备绝缘可靠性的关键。文中提出了基于汤逊放电的C_(4)F_(7)N气体摩尔分数的新检测方法,该方法采用一定条件下汤逊放电电流对应的电压值来表征C_(4)F_(7)N气体混合比例。首先开展了不同混合摩尔分数、不同气压下C_(4)F_(7)N/CO_(2)混合气体的稳态汤逊放电试验,建立了摩尔分数与电压的关系,发现该方法可检测摩尔分数0~100%范围,在可能用到的5%~30%范围的比例检测误差不超过0.4%;然后从理论上分析了所提出方法的可行性,证明C_(4)F_(7)N/CO_(2)混合气体中C_(4)F_(7)N气体占比在0~100%范围内的汤逊放电电流对应的电压值与混合比例之间存在线性关系。最后,将文中提出的方法与色谱法、红外/紫外光谱法之间进行了对比,指出了该检测方法在成本和耗气量方面的独特优势。研究结果可为所提方法的实际应用提供理论和实验依据。

C_(4)F_(7)N/CO_(2) mixed gas,as a new type of environment-friendly insulating gas,has been applied in practical equipment.Timely detection to ensure that the mixing proportion of mixed gas remains stable is the key to ensure the insulation reliability of equipment.In this paper,a new molar ratio detection method of C_(4)F_(7)N gas in mixed gas is proposed.In this method,the voltage value corresponding to townsend discharge current under certain conditions is adopted to characterize the C_(4)F_(7)N gas mixing ratio.Firstly,the steady-state townsend discharge test of C_(4)F_(7)N/CO_(2) mixed gas under different mixing ratios and different pressures was carried out,and the relationship between molar ratio and voltage was established.It is found that the proposed method can be adopted to detect the mixing ratio range of 0~100%,and the detection error in the commonly-used range of 5%~30%is less than 0.4%.Then,the feasibility of the proposed method is theoretically analyzed,and it is proved that there is a linear relationship between the voltage value corresponding to the townsend discharge current and the mixing ratio when the mixing ratio of C_(4)F_(7)N/CO_(2) is in the range of 0~100%.Finally,the method proposed in this paper was compared with chromatography and infrared/ultraviolet spectroscopy,and the unique advantages of the detection method in cost and gas consumption are pointed out.The results can provide theoretical and experimental bases for the practical application of this method.