近红外激光光声变压器油溶解气分析技术研究

Knowledge of the condition of transformers is essential for all electrical grids and on-line monitoring of critical transformers is increasingly vital. The information helps operators to manage their assets and make decisions on continuing operation, maintenance or replacement. Dissolved Gas-in-oil Analysis (DGA) is the most important test for condition assessment of transformers as it is a well established method of transformer diagnosis. Many transformer failures can be prevented through the correlation of DGA data to real events. .A novel near infrared laser based photoacoustic (PA) DGA monitoring solution is proposed in this project. Instead of thermal radiation source and electric microphone used in traditional PA DGA monitors, a broadband tunable erbium doped fiber laser in tandem with a high output power fiber amplifier and an optical fiber microphone are applied in the new PA DGA monitoring system. Furthermore a wavelength scan and frequency modulation mechanism is used instead of an optical intensity modulation method. The new integration of these advanced techniques results in a significant improvement of the performances of the PA DAG monitor system. A sub-ppb level detectable concentration limit for C2H2 and sub-ppm to ppm level detectable limits for C2H4, CO, CO2 and H2O gases are expected. As the gas sensing unit is an all-optical detector and without any moving part, the system is immune from electromagnetic and mechanical vibration interference. .To take the advantages of sub-ppb level detectable sensitivity, a deeper investigation of correlation between weak partial discharge intensity and dissolved gas concentration is also proposed. The results of the study will provide a clear theoretical model and experimental data for transformer's early fault evolution. Therefore a new transformer's early diagnosis and infancy fault warning guide rule is expectantly established. .The project is proposed based on a strong research background of the applicant's team. Many innovative progresses have been carried out during the past 10 years by the team on the field of laser based photoacoustic spectroscopy. The works include the development of infrared gas lasers, optical parameter oscillator, difference frequency generator and thermal radiation source based photoacoustic spectrometer. Their laboratory and advanced experiment equipment will sufficiently support the successful implementation of the project.

为保障电网安全、可靠和经济地运行，需要对大型浸油变压器的健康状况进行连续的在线监测。变压器油中溶解气分析（DGA）是诊断变压器潜伏性故障最为有效的方法。本项目提出了一种新的激光光声DGA监测技术方案。通过集成近红外宽带可调谐光纤激光器、高性能光纤声波传感器和共振式光声池，结合波长扫描和频率调制技术构成的光声DGA监测系统，可以实现对多种变压器故障特征气体的同时测量，其中对乙炔的测量灵敏度预期可达到亚 ppb量级。此外该系统还具有气体传感单元的全光学感测、易于远距离遥测和无机械运动部件的特点， 因而从本质上解决了目前DGA 光声监测技术的易受电磁干扰和机械振动影响的问题。利用该系统的高灵敏度特点，提出了通过对变压器油中放电产物的测量，研究变压器早期故障演化规律和建立新的早期故障诊断判据的研究方案。本项目研究结果将为大型电力变压器故障的早期诊断和电网运行安全监测提供一种新的技术手段。

大型电力变压器是电力系统中的核心设备，为保障电网安全、可靠和经济地运行，需要对变压器的运行状态进行连续的在线监测。变压器油中溶解气分析（DGA）是诊断变压器潜伏性故障最为有效的方法。本项目提出了一种新的激光光声DGA监测技术方案。通过集成近红外宽带可调谐光纤激光器、高性能光纤声波传感器和共振式光声池，结合波长扫描和频率调制技术构成的光声DGA监测系统，可以实现对多种变压器故障特征气体的同时测量。. 本项目研究工作主要围绕项目核心研究目标和关键技术展开，包括（1）近红外光声光谱激发光源研究；（2）高性能光纤声波传感器研究；（3）变压器油溶解气中多气体成分分析方法研究；（4）光声DGA监测系统集成；（5）压器油溶解气的高效分离方法研究；（6）变压器油中微弱放电与气体产率关系研究。. 本项目已经完成计划的研究内容，实现了预期的研究目标。本项目首次采用基于近红外宽带可调谐激光光声微量气体检测方法的变压器油溶解气分析（DGA）技术，实现了对变压器主要故障特征气体的高灵敏度测量；首次研制出光声激励光、光声信号感测和传输均通过光纤传输的全光光声光谱气体分析系统；基于该激光光声光谱变压器DGA在线监测方法，搭建了变压器故障特征气体检测模拟实验平台，首次实现了对警示变压器局部放电的关键特征气体C2H2 ppb量级的检测灵敏度，同时实现了对CH4、CO、CO2以及H2O气体的ppm量级的检测灵敏度。该系统还具有气体传感单元的全光学感测、易于远距离遥测和无机械运动部件的特点，从本质上解决了目前DGA光声监测技术的易受电磁干扰和机械振动影响的问题。本项目研究结果将为大型电力变压器故障的早期诊断和电网运行安全监测提供一种新的技术手段。.本项目共计发表学术论文18篇，申请并获得授权国家发明专利2项，培养硕士研究生7人，博士研究生3人。