【作者】 杨小峰；

【导师】 康东；

【作者基本信息】 成都理工大学 ， 核资源与核勘查工程， 2010， 硕士

【摘要】 核电是一种技术成熟、可大规模生产的安全、经济、清洁的能源,在我国能源战略中占有很大的比重。进入新世纪以后,核电进入快速发展阶段,在“积极推进核电发展”方针的指导下,我国制定了核电“2020年中国核电运行装机容量7000万千瓦,在建3000万千瓦”的规划目标。由此可见,我国核电将迎来发展高峰时期,从而对核电力设施如电缆、变压器等设备的安全运行监控将成为一项重大任务。以电信号为工作基础的传统温度传感器,如热电偶,热敏电阻,热释电探测器等温度传感器的发展已经非常成熟,它们以其结构简单、测量精度高、成本低等特点而广泛应用在国民经济、科研、国防等领域。但在强电磁干扰或易燃易爆的场合下,传统温度传感器受到很大的限制。随着半导体激光技术、光纤传感技术及数字信号处理等技术的发展,分布式光纤测温技术有了飞速发展。分布式光纤测温系统是一种实时、在线、多点温度测量系统,已成为工业过程控制中一种新的检测手段。分布式光纤测温技术以光时域反射(Optical Time-Domain Reflectometry,简称OTDR)原理和光纤后向拉曼散射温敏效应(Raman scattering Effect)为理论基础。其中OTDR技术用于实现温度定位,拉曼散射效应用于实现温度测量。与传统温度传感器相比,分布式光纤测温系统采用光纤作为传感元件和信息传输通道,具有电绝缘性、耐腐蚀性、信号传输带宽宽、信息长距离传输损耗低等固有特性和本质安全性,为强电磁场、高压大电流、易燃易爆、复杂几何空间等恶劣环境(如地下电缆,船舶等)的温度测试提供了可行的方法。本论文对比传统温度传感器,提出了基于分布式光纤测温在核电系统中实现的一种方法。该测温系统由激光发射系统、波分复用系统、温度定标系统、APD接收系统、USB双通道高速数据采集系统和微处理器系统组成。激光发射系统主要产生具有一定宽度和重复频率的脉冲信号;波分复用系统主要完成激光耦合及提取后向拉曼散射中斯托克斯光和反斯托克斯光;温度定标系统主要完成测量系统的初始化标定;APD接收系统主要实现斯托克斯和反斯托克斯光信号的光电转换;USB双通道高速数据采集系统主要完成大量模拟量到数字量的转换和缓存;ARM微控制系统为整个温度测量系统的核心,主要实现实时数据的采集、存储、分析及报警等功能。分布式光纤测温系统的工作过程分为四个阶段。首先,微控制系统控制激光器产生大功率激光脉冲,光脉冲经光路耦合器进入一段放置在恒温槽中的光纤,然后进入传感光纤;其次,激光将在传感光纤中发生散射,携带温度信息的后向拉曼散射光返回经光路耦合器和分光器将两不同中心波长的斯托克斯光和反斯托克斯光分离;再次,分离的两路光信号经接收机进行光电转换和放大后由数据采集单元进行高速数据采样并转换为数字量;最后,微处理器对信号进一步处理,解调出温度值。分布式光纤测温系统以ARM9微处理系统和USB高速数据采集电路为主要硬件平台。在嵌入式Linux系统下,通过软件编程及基于MiniGUI用户图形界面系统开发,使系统成为具有高速数据处理、存储、网络等功能的实时动态温度监控系统。系统性能测试表明,系统空间分辨率、温度分辨率及响应时间等指标满足设计要求,系统在实际应用中可靠性高和抗干扰能力强,温度实时监控效果良好。更多还原

【Abstract】 Nuclear power is a safe, economical and clean energy. It is widely used and occupies a large proportion in national strategy. And it has entered a rapid development stage in the new century. Under the guidance of the principle which is "actively promoting nuclear power development" the government has developed a nuclear power plan, which is "70 million kilowatts by 2020, 30 million kilowatts under-construction " . Therefore, the safety monitoring of nuclear power facilities such as cables, transformers and other equipment is a major task.Traditional temperature sensors which based on electrical-signal have been very mature. They are simple, high precision, low cost and widely used in the national economy, scientific research, defense and other fields. However, the traditional temperature sensor is greatly restricted in the strong electromagnetic interference or flammable occasions.As the development of semiconductor, laser technology, optical fiber sensing technology and digital signal processing technology, distributed fiber temperature measurement has greatly developed. Distributed Fiber Temperature-measured System (Distributed Fiber Temperature-measured System , referred to as DFTS ) is a real-time, online, multi-point fiber optic temperature measurement system. And it has become a new methods and technologies in industrial control system.DFTS based on Optical Time-Domain Reflectometry (Optical Time-Domain Reflectometry, referred to as OTDR) and Raman-scattering Effect. OTDR technology is used to get coordinates. And Raman-scattering Effect is used to get the value of temperature.Compared with conventional temperature sensors, DFTS takes optical fiber as the sensing element and the information transmission channel. This system has electrical insulation, corrosion resistance, wide signal bandwidth and low loss for long distance transmission. So, it’s a very new method for temperature mesurement in strong electromagnetic fields, high voltage high current, inflammable, explosive, complex geometry of space and other harsh environment (such as underground cables, ships, etc.). This paper presents a method which based on principles of distributed fiber optic temperature measurement on temperature morning in nuclear power system. The DFTS consists of laser emission system, wavelength division multiplexing systems, temperature calibration system, APD receiver, dual-channel high-speed USB data acquisition system and the microprocessor system.The working process of DFTS is divided into four stages. First, the laser controlled by microprocessor produces high-power laser pulse. Then couples the pulse into sensing fiber; Secondly, strips out of the Stokes and anti-Stokes light; Third, takes care of the isolated light signals by data acquisition unit; Finally, the microprocessor demodulates the value of temperature by calculating.DFTS mainly uses ARM9 microprocessor system and high-speed usb data acquisition circuit as hardware platform. And its software design bases on MiniGUI and embedded linux. So DFTS is a real-time, dynamic temperature morning system. Futhermore, it has the network, storage, high-speed data processing and other functions.System test shows that the system indicators such as spatial resolution, temperature resolution and response time meet the design requirements. And it has high reliability and strong anti-interference ability in practical applications.更多还原