六氟化硫中痕量一氧化碳和二氧化碳的气相色谱检测及其在断路器故障分析中的应用

Gas chromatographic determination of trace carbon monoxide and carbon dioxide in sulfur hexafluoride and its application to probing potential breakdown of high-voltage circuit breaker

为了准确分析高浓度SF6中痕量的CO及CO2,发展了可靠的气相色谱-火焰离子化检测器(GC-FID)方法。通过双Porapak Q色谱柱结合阀切换将SF6从待测样品中分离并排出检测系统,从而避免SF6可能造成的在线转化柱中毒现象,同时实现CO和CO2的完全分离;通过在线镍催化将CO和CO2的检测转化为对CH4的检测,极大地提高检测灵敏度。结果显示,该方法对CO和CO2的检测互不干扰,两者都可在2~500μL/L范围内呈现良好的线性相应,测定重复性好(RSD小于2%),准确度高。建立的GC-FID方法可直接用于SF6高压断路器中痕量CO及CO2的检测,为SF6相关电气设备潜伏性故障诊断提供了研究手段。

A reliable gas chromatography-flame ionization detector(GC-FID)method was developed for the accurate determination of trace CO and CO2 in high concentration of SF6.Using a combination of dual Porapak Q chromatographic columns with valve switching,SF6 was separated from the tested samples and blown out of the detection system,with the aim of ruling out the possibility of conversion column poisoning.Meanwhile,CO and CO2 were on-line separated and subsequently converted to CH4 in the presence of a nickel catalyst to increase the sensitivity for the determination of carbon-borne gases.The results showed that neither gas interfered with the determination of the other.Satisfactory linearities were achieved in the range 2-500μL/L for both CO and CO2,with highly accurate and reproducible determination(RSD<2%).The developed GC-FID method is applicable to the determination of gases lodged in high-voltage circuit breakers toward the analysis of trace CO and CO2,thus providing a tool for probing the potential breakdown of SF6-insulated equipment.