SF6气体在放电或过热时会发生电离和分解，产生多种气体分解物。这些分解物会影响电气设备的绝缘性能。但现有的红外气体检测手段均无法对SF6分解气体进行现场在线测量。根据实际需求，本文根据光栅分光的原理设计了一种红外光谱检测系统。该系统可对SF6分解气体的成分和含量进行实时测量，可在电气设备带电运行的状态下进行在线测量。测量数据为分析设备的性能和安全状况提供有力的依据。

SF6 gas may be ionized or decomposed into a variety of gases when discharge or overheat occurs. These decomposed gases can affect the insulation of electric power equipment. However, all of the existing infrared gas detection means can not measure the decomposed SF6 gas on line in situ. According to the practical needs, an infrared spectrometer system based on the principle of a grating is designed. The system can measure the components and contents of the decomposed SF6 gasin real time and can operate on line when the electric equipment is in the running state. The measured data provide convincing gist for the analysis of the performance and safety of the electric equipment.