分布式光纤温度传感系统性能优化及火源定位方法研究

发布时间：2018-01-29 01:25

本文关键词： 分布式光纤温度传感系统空间分辨率测温准确度火源定位位置校准　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：分布式光纤温度传感(DistributedTemperature Sensor,DTS)是一种对沿光纤方向温度场分布进行实时连续测量的技术,被广泛应用于仓储、油气管道等大型基础工程设施的安全健康监测中。DTS系统主要基于拉曼散射的温度效应进行温度测量,结合光时域反射(Optical Time Domain Reflectometer,OTDR)技术对光纤各点的位置实现定位,从而得到光纤沿线的各点的温度信息。火灾预警技术,作为安全健康监控技术的重要组成部分,为火灾的早期发现提供了有力的保障,能够有效避免火灾的灾难性后果。论文针对DTS系统的性能优化方法和基于DTS系统的火源定位方法进行了深入研究,主要包括以下几个方面的内容:首先,叙述了 DTS系统中拉曼散射原理和实现温度定位的OTDR技术原理,并分析比较了 DTS系统的三种温度解调方法。其次,搭建了 DTS实验系统,分析了系统的性能指标;针对空间分辨率影响测温误差的问题,提出线性拟合法将系统的空间分辨率从5m提高到1m,有效地减小了温度测量误差。使用环形结构的DTS系统消除了斯托克斯拉曼散射光和反斯托克斯拉曼散射光的衰减系数不同的影响,针对波分复用器隔离度不足引起的拉曼散射光中含有部分瑞利噪声的问题,通过预先标定的方法扣除瑞利噪声来解调温度,有效地提高了系统的测温准确度。最后,基于封闭空间内的温度场分布特点,结合传感光纤容易布线,可长距离温度实时测量的优点,提出了双光纤平行结构和垂直结构的火源定位方法。针对双光纤平行结构火源位置坐标误差较大的问题,提出采用滑动平均的方法在一定程度上减小了火源位置坐标的误差;为实现火源定位的可视化,提出了分区域计数法,结合三次样条插值,有效地减少了火源定位需要的时间。双光纤垂直结构火源定位方法比较简单,容易操作。提出了温度曲线滑动平均法和峰值半宽度法修正了由不平坦隔热顶板引起的火源定位偏差,实现了快速准确的火源定位。
[Abstract]:Distributed temperature Sensor DTS (distributed temperature Sensor) is a real-time and continuous measurement technique for the temperature field along the fiber. DTS system is widely used in the safety and health monitoring of large-scale infrastructure such as storage, oil and gas pipeline and so on. The temperature measurement is mainly based on the temperature effect of Raman scattering. Combined with optical time domain reflectance (OTDR) technique, the position of each point of optical fiber can be located. As an important part of the safety and health monitoring technology, the temperature information of each point along the optical fiber and the fire warning technology provide a powerful guarantee for the early detection of the fire. It can effectively avoid the catastrophic consequences of fire. This paper focuses on the performance optimization method of DTS system and the fire source location method based on DTS system. It mainly includes the following aspects: firstly, the principle of Raman scattering in DTS system and the principle of OTDR technology to realize temperature localization are described. Three temperature demodulation methods of DTS system are analyzed and compared. Secondly, the DTS experimental system is built and the performance index of the system is analyzed. Aiming at the problem that spatial resolution affects the error of temperature measurement, a linear fitting method is proposed to improve the spatial resolution of the system from 5m to 1m. The error of temperature measurement is reduced effectively. The influence of different attenuation coefficients of Stokes Raman scattering light and anti Stokes Raman scattering light is eliminated by using DTS system with annular structure. In order to solve the problem of Rayleigh noise in Raman scattering light caused by insufficient isolation of wavelength division multiplexer (WDM), the Rayleigh noise is deducted from Rayleigh noise to demodulate the temperature by pre-calibration. The accuracy of temperature measurement is improved effectively. Finally, based on the distribution of temperature field in closed space, the sensor fiber is easy to be wired and can be measured in real time over long distance. In this paper, the fire source location method for parallel and vertical structures of double optical fiber is proposed, aiming at the problem that the coordinate error of fire source in parallel structure of double optical fiber is large. The method of moving average is used to reduce the error of fire source coordinate to some extent. In order to realize the visualization of fire source location, a method of area counting is proposed, which combines cubic spline interpolation to effectively reduce the time required for fire source location. The method of fire source location with double fiber vertical structure is relatively simple. The temperature curve moving average method and the peak half width method are put forward to correct the fire source location deviation caused by uneven heat insulation roof, and the fast and accurate fire source location is realized.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TP212

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