摘要
高准确度、高灵敏度检测故障特征气体是基于油中溶解气体分析的变压器早期潜伏性故障诊断的关键。基于差频中红外及离轴腔增强吸收光谱技术,搭建了一个变压器油中溶解气体检测系统。以故障混合气体中浓度为0.5μL/L的C2H4为代表,验证了该系统的检测特性。选取1 583.0 nm信号源及1 063.8 nm抽运源,利用非线性光学周期极化铌酸锂晶体,结合准相位匹配技术,差频产生了3.245μm(对应C2H4的基频吸收线3 081.001 6 cm-1)的中红外相干光:最大输出功率为288μW,最大调谐范围为35 cm-1。气体压强100 Torr下,系统对于气体C2H4的最低吸收系数及检测下限分别为7.39×10-10 cm-1及0.014 4μL/L,很好地满足了变压器油中溶解乙烯检测极限值(0.5μL/L)的需要,分析和证明了气体压强对C2H4的吸收峰值、系统最低吸收系数及检测下限的影响。该研究结果为基于差频中红外吸收光谱的变压器油中溶解气体带电检测提供了理论依据和技术支撑。
A highly accurate and sensitive detection of fault characteristic gases is the key to diagnosing incipient transformer faults through dissolved gases analysis. In this paper, based on mid-infrared difference frequency generation and off-axis cavity enhanced absorption spectroscopy technology, a detection system for dissolved gases in transformer oil was built up. The C2H4with concentration of 0.5μL/L in multiple fault gases dissolved in transformer oil was taken as a representative to verify the detection characteristics of this system. Combined with quasi-phase- matched （QPM）, the signal source （1583.0nm） and pump source （1063.8nm） had been adopted in a compact and fibre- coupled periodically poled lithium niobate （PPLN） waveguide module, generating 288μW of 3.245μm wavelength laser light with a wide tunability range of 35cm-1. The wavelength of 3.245μm is corresponded to fundamental frequency absorption line 3081.0016cm-1 of C2H4. The lowest absorption coefficient and detection limit of this system for C2H4 is 7.39x10^10 cm-1 and 0.0144μL/L at gas pressure of 100Torr respectively, which well satisfies the requirement of detection limit （0.5μL/L） for C2H4dissolved in transformer. The effects of gas pressure on the absorption peak value, lowest absorption coefficient and detection limit of system for C2H4 were also analyzed and demonstrated. This provides theoretical basis and technical support for transformer oil-dissolved gases live detection based on mid-infrared absorption spectroscopy with difference frequency generation.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2015年第18期4833-4839,共7页
Proceedings of the CSEE
基金
国家创新研究群体基金(51021005)
国家重大科学仪器设备开发专项(2012YQ160007)~~
关键词
油中溶解气体分析
特征吸收谱线
差频中红外
准相位匹配
离轴腔增强吸收光谱
oil-dissolved gas analysis
characteristic absorption lines
mid-infrared difference frequency generation
quasi-phase-match
off-axis cavity enhanced absorption spectroscopy
