变压器油中多组分气体高精度在线检测研究

针对多组分气体测量精度低、交叉影响等问题，建立了一种高精度多气体网络式在线检测系统。系统中采用窄线宽激光器作为光源，设计了新型长光程气室，通过单一高频三角信号调制激光光谱，利用谐波检测技术和光学时分、空分复用技术相结合，实现了三种气体(CO，CH₄，C₂H₂)的同时多点高精度在线测量。实验结果表明，多气体浓度测量最大相对误差小于4%，每种气体响应时间均小于15 s。该系统多气体检测精度高、响应时间快，非常适合用于变压器绝缘油中多组分气体实时在线检测。

Study on High Accuracy Detection of Multi-Component Gas in Oil-Immerse Power Transformer

In order to solve the problem of low accuracy and mutual interference in multi-component gas detection, a kind of multi-component gas detection network with high accuracy was designed. A semiconductor laser with narrow bandwidth was utilized as light source and a novel long-path gas cell was also used in this system. By taking the single sine signal to modulate the spectrum of laser and using space division multiplexing (SDM) and time division multiplexing (TDM) technique, the detection of multi-component gas was achieved. The experiments indicate that the linearity relevance coefficient is 0.99 and the measurement relative error is less than 4%. The system dynamic response time is less than 15 s, by filling a volume of multi-component gas into the gas cell gradually. The system has advantages of high accuracy and quick response, which can be used in the fault gas on-line monitoring for power transformers in real time.