激光拉曼光谱应用于变压器油中溶解气体分析

Analysis of Dissolved Gas in Transformer Oil Based on Laser Raman Spectroscopy

变压器油中溶解气体在线监测是实施变压器状态检修的重要手段之一。激光拉曼光谱技术能直接使用单一频率的激光对混合气体进行非接触式的测量,符合在线监测的要求。利用激光拉曼光谱对变压器油中溶解气体进行分析,能克服传统在线监测方法的诸多不足。对激光拉曼光谱在变压器油中溶解气体分析中的应用进行了研究。分析了变压器油中7种主要故障特征气体(H2、CH4、C2H6、C2H4、C2H2、CO、CO2)的拉曼特征频谱,并阐述了基于特征频谱和最小二乘法对7种特征气体进行定性定量分析的方法。利用共聚焦拉曼技术和镀银石英玻璃管制成的气体样品池,构建了激光拉曼光谱气体分析试验平台。结合平台研究了7种故障特征气体的拉曼光谱检测特性,并与实验室气相色谱法的测量结果进行了对比。对比结果表明,激光拉曼光谱能有效地对变压器油中溶解气体进行定量分析,为变压器油中溶解气体的拉曼光谱在线监测奠定了基础。

Dissolved gas-in-oil online monitoring is one of the important means to implement condition-based maintenance for power transformer. Laser Raman spectroscopy （LRS） can directly perform non-contact measurement to mixed gas by a laser with single frequency, especially being suitable for online monitoring. Using LRS to analyze dissolved gas in transformer oil can overcome the disadvantages of traditional online monitoring methods. In this paper, the application of LRS in the dissolved gas-in-oil analysis （DGA） was studied. The Raman characteristic spectra of seven major fault characteristic gases（H2, CH4, C2H6, C2H4, C2H2, CO, CO2） were analyzed, and the qualitative and quantitative analysis methods for the seven characteristic gases based on the characteristic spectra and the least squares method were elaborated. Laser Raman spectroscopy gas detection test platform was built using confocal Raman technology and gas sample cell made by silver plated quartz glass tube. Utilizing this platform, the Raman spectrometry detection characteristics of the seven fault characteristic gases were studied, and the test results were compared with the results measured by gas chromatography in laboratory. The comparison results show that LRS can quantitatively analyze dissolved gas in transformer oil effectively, which lays the foundation for the online monitoring of dissolved gas in transformer oil with LRS.