应用拉曼光谱分析变压器油中溶解乙酸含量

摘要

Acetic acid is the main component of acids generated through oil-paper insulation aging.The analysis of the content of acetic acid dissolved in the transformer oil is of great significance for evaluating the aging state of operating transformer.Raman spectroscopy is a molecular analysis technology based on the Raman effect,which can be applied to perform non-contact in-situ detection of substance.In this paper,the application of laser Raman spectroscopy in the detection of acetic acid dissolved in the transformer oil was studied.Gaussian 09W simulation software was applied to analyze the Raman vibration characteristics of ace-tic acid.Also,the vibration modes of the Raman spectral peaks of acetic acid were identified.Acetic acids at different concentra-tions dissolved in the transformer oil were directly detected based on the laser Raman spectroscopy liquid detection platform. Acetic acid was characterized by Raman signal at 891 cm-1 .The quantitative analysis method for acetic acid was established based on the Raman peak area ratio,A891 cm-1/A932 cm-1 ,and the least squares method.Current detection limits of 0.08 mg· mL-1 acetic acid concentration were obtained.The experimental results show that laser Raman spectroscopy can be used in the analysis of the content of acetic acid dissolved in the transformer oil which has a good detection stability and reproducibility.The research in this paper provides a new alternative method for the rapid and nondestructive detection of acetic acid dissolved in the transformer oil.%乙酸是变压器油纸绝缘老化所生成酸类物质的主要成分;分析变压器油中溶解乙酸含量对准确评估运行变压器的老化状态具有重要意义.拉曼光谱技术是基于拉曼效应的一种分子分析技术,能很好地用于物质的非接触式原位检测.论文开展了变压器油中溶解乙酸含量拉曼光谱检测方法研究:利用Gaussian 09W软件分析了乙酸分子的拉曼振动特性,对实测乙酸拉曼谱峰的振动模式进行了指认;基于实验室搭建的激光拉曼光谱液体检测平台,对不同乙酸含量的变压器油样进行了原位检测;选定891 cm-1作为变压器油中溶解乙酸分子的拉曼特征峰,基于乙酸891 cm-1与变压器油932 cm-1特征峰面积比值和最小二乘法建立了乙酸的定量分析方法,检测限可达0.08 mg·mL-1.实验结果表明:激光拉曼光谱可应用于油中溶解乙酸含量原位检测并具有良好的检测稳定性和重复性,为变压器油中溶解乙酸含量的快速、无损检测提供了一种新方法.