基于近红外TDLAS变压器油中溶解气体在线检测装置

A Near-Infrared TDLAS Online Detection Device for Dissolved Gas in Transformer Oil

变压器绝缘油以链烷烃(C n H 2 n+2)为主要化学成分,在变压器长期运行过程中因电弧、放电、过热、受潮等原因导致化学键逐步发生断裂,产生与故障有关的故障判别气体(CH_(4),C_(2)H 2,C_(2)H_(4),C_(2)H 6,CO和CO_(2)),因此变压器绝缘油中会溶解多组分气体,故需要一种多组分气体的在线检测装置,以保证变压器的正常运行。针对电力行业装配需求,研制基于可调谐激光吸收光谱法(TDLAS)多组分气体的在线检测装置。针对6种故障特征气体的近红外吸收波段,分别选取1580,1654,1626和1530 nm四个近红外激光器,使用分时扫描的时分多路技术,实现对多组分气体的分时快速顺序检测并采用波长调制技术,消除背景气体的交叉干扰。主要检测气体为绝缘油化学键断裂所产生的烃类化合物(CH_(4),C_(2)H 2,C_(2)H_(4)和C_(2)H 6)和碳氧化合物(CO和CO_(2))。在线检测,与变压器油气象色谱测量方法进行对比实验,并对其进行工况稳定性测试。实验结果表明:乙炔浓度测量范围为0.5~1000μL·L^(-1),范围小于5μL·L^(-1)时最大测量误差小于0.8,5~1000μL·L^(-1)时最大误差在6μL·L^(-1)以下;甲烷、乙烷、乙烯的浓度测量范围为0.5~1000μL·L^(-1),最大测量误差小于6μL·L^(-1);碳氧化合物(CO和CO_(2))测量范围分别为25~5000,25~15000μL·L^(-1),最大测量误差分别在2与20μL·L^(-1)以下。所设计的近红外TDLAS多组分气体检测装置能够用于变压器油中溶解气体的在线检测,测量的气体浓度满足在线检测要求,能够稳定运行且适应恶劣工况条件,为检测变压器油中溶解气体在线测量提供了有效的实践经验。

Transformer insulating oil uses paraffin(C n H 2 n+2)as the main chemical component.Due to electric arc,discharge,overheating,moisture,etc.,the chemical bonds are broken,and characteristic gases(methane,ethane,ethylene,acetylene,carbon dioxide,carbon monoxide)are generated during the long-term operation of the transformer.Therefore,Multi-component gas will be dissolved in transformer insulating oil,so an online detection device for multi-component gas is needed to ensure the normal operation of the transformer.According to the assembly requirements of the power industry,this paper conducts an online detection device of 6 types of fault characteristic gases based on near-infrared tunable diode laser absorption spectroscopy(TDLAS).Based on the near-infrared absorption bands of 6 types of fault characteristic gases,the device selects four near-infrared lasers at 1580,1654,1626 and 1530 nm respectively.It uses the time-division multiplexing technology of time-sharing scanning to achieve fast time-sharing of multi-component gases Sequentially detect and adopt wavelength modulation technology to eliminate the cross-interference of the background gas.The designed near-infrared TDALS multi-component gas detection device mainly detects methane(CH_(4)),ethane(C_(2)H 6),ethylene(C_(2)H_(4)),acetylene(C_(2)H 2),carbon monoxide(CO)and carbon dioxide(CO_(2)).The developed experimental device is verified with the traditional transformer oil dissolved gas method(transformer oil meteorological chromatographic measurement method),and the working condition stability test is carried out.The measurement range of acetylene concentration is 0.5~1000μL·L^(-1).When the range is less than 5μL·L^(-1),the maximum measurement error is less than 0.8μL·L^(-1).When the range is 5~1000μL·L^(-1),the maximum error is below 6μL·L^(-1);the concentration measurement range of methane,ethane,and ethylene is 0.5~1000μL·L^(-1),the maximum measurement error is less than 6 ppm;The measurement ranges of CO and O_(2) are 25~5000 and 25~15000μL·L^(-1),and their maximum measurement errors are below 2 and 20μL·L^(-1) respectively.The designed near-infrared TDALS multi-component gas detection device can be used for online detection of dissolved gases in transformer oil,and the measurement meets the requirements of online detection.It can operate stably and adapt to harsh working conditions.The successful design of this on-line detection device provides practical experience for on-line measurement of dissolved gases in the detection of transformer oil.