摘要
乙烷是电力变压器油中溶解的主要故障特征气体之一,其高精度、高灵敏度检测是进行油中溶解气体分析的关键。基于光反馈原理及腔增强吸收光谱技术,结合量子级联激光器,建立了一套变压器油中溶解乙烷气体检测系统。基于腔内单腔模对称理论,通过LabVIEW编程来实现反馈光与腔谐振的相位匹配。研究并实现了光学反馈效应(激光将在延迟一定的时间后,返回激光腔并锁定腔模式共振频率)、偶数和奇数模式效应(交替出现强度较大和较小的腔模式)、激光器阈值电流降低效应(约1.2mA)。利用腔衰荡光谱检测技术测得的系统有效反射率、腔品质因素分别为99.978%和7138.4,系统光谱分辨率达到0.005 2cm-1。标准大气压、温度20℃下,1s的积分时间内,对乙烷PQ3吸收线进行检测,系统检测准确率及检测极限分别达到95.72%±0.17%和(1.97±0.06)×10-3μL·L-1,满足了变压器油中溶解乙烷气体检测的需要。
Ethane is one of major fault characteristic gases dissolved in power transformer ,the detection of Ethane with high ac‐curacy and sensitivity is the key of dissolved gas analysis .In this paper ,based on optical feedback theory and cavity‐enhanced ab‐sorption spectroscopy ,combined with quantum cascade laser ,a detection system for dissolved gas C2 H6 in transformer oil was built up .Based on the symmetry of the individual cavity modes ,the phase matching of returning light in resonance with the cavi‐ty was achieved through LabVIEW codes .The optical feedback effect that the emitted light return to the laser cavity after a small delay time and lock to the resonance frequency of cavity ,even and odd modes effect that the higher modes and lower modes structure will build up alternatively ,and threshold current lowering effect of about 1.2 mA were studied and achieved .By cavity ring‐down spectroscopy ,the effective reflectivity of 99.978% and cavity finesse of 7 138.4 is obtained respectively .The fre‐quency selectivity is 0.005 2 cm^-1 .With an acquisition time of 1s ,this optical system allows detection for the P Q3 band of C2 H6 with high accuracy of 95.72% ± 0.17% and detection limit of （1.97 ± 0.06） × 10^-3 μL·L^ -1 at atmospheric pressure and tem‐perature of 20 ℃ ,which lays a foundation for fault diagnose from dissolved gas analysis .
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2015年第10期2792-2796,共5页
Spectroscopy and Spectral Analysis
基金
国家创新研究群体基金(51321063)
国家重大科学仪器设备开发专项(2012YQ160007)资助
关键词
腔增强吸收光谱技术
光学反馈
乙烷
溶解气体分析
Cavity-enhanced absorption spectroscopy
Optical feedback
Ethane
Dissolved gas analysis
