基于光纤F-P腔的超声波信号检测与分析

发布时间：2018-01-13 14:35

本文关键词：基于光纤F-P腔的超声波信号检测与分析　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：电力变压器的局部放电往往会对电力变电站的运行设备带来极大的破坏,造成不可挽回的经济损失。局部放电会产生超声波等一系列物理现象,可以通过检测超声波信号来判断变压器是否有局部放电的情况,一旦变压器出现故障能及时抢修。受限于变压器周围强电磁场、易腐蚀等原因,传统的压电式超声波传感器不能在变压器检测中使用。光纤F-P腔超声波传感器以其抗电磁干扰、耐腐蚀、精确度高、质地轻、可挠曲等优点,能很好的运用于变压器检测系统中。本文根据法布里-珀罗腔光线干涉原理,制备了光纤F-P腔超声波传感器,利用其传感特性搭建了光纤超声波传感器解调系统,利用采集到的超声波信号进行解调分析,对提高光纤F-P腔超声波传感器的灵敏度展开了深入研究。主要研究内容如下:(1)根据F-P腔的多光束干涉理论以及传感原理,设计了一种光纤F-P腔超声波传感器,分析了强度型解调与相位型解调的基本原理。分析了石英膜片的结构参数对灵敏度与谐振频率的影响,通过ANSYS仿真软件Workbench平台对不同结构参数的膜片进行仿真对比,优化了超声波传感器石英膜片的有效半径和厚度参数,制备了 3只光纤F-P腔超声波传感器。(2)根据对高速超声波信号的检测原理,研制了光纤F-P腔超声波传感器解调系统。对该系统硬件电路进行了详细的设计,对DFB窄带激光二极管、低噪声光电二极管和光纤耦合器等光学元器件的选型,以及对这些光学器件接口和法兰盘的分析。通过对放大器芯片、电源芯片和AD采集芯片的选型,研制了放大电路、电源转换模块和A/D数据采集模块,搭建了光纤F-P腔超声波传感器解调系统。研发了系统上位机软件,上位机通过USB 口与解调仪采集模块通讯,具有实时采集数据、存储数据库,数据不同显示方式,参数配置和性能分析等功能,通过测试,上位机采集功能、数据存储功能、显示功能等正常。(3)利用电子脉冲放电产生超声波信号,通过光纤F-P腔超声波传感器和压电陶瓷传感器对信号进行采集检测,通过采集的两种传感器在同种局放源下的输出电压幅值,研究了传感器输出电压幅值与超声波声压的关系。通过3只光纤F-P腔超声波传感器横向对比实验研究了传感器的结构参数和固有频率对灵敏度的影响;研究了光纤F-P腔超声波传感器在不同介质中的阻尼对灵敏度的影响;对比了光纤传感器和压电式传感器的测试性能。
[Abstract]:Partial discharge of power transformer often brings great damage to the operation equipment of power substation, causing irreparable economic loss. Partial discharge will produce a series of physical phenomena such as ultrasonic wave. Ultrasonic signals can be detected to determine whether the transformer has partial discharge, once the transformer fault can be repaired in time, limited by the strong electromagnetic field around the transformer, easy to corrosion and other reasons. Traditional piezoelectric ultrasonic sensor can not be used in transformer detection. Fiber F-P cavity ultrasonic sensor has the advantages of anti-electromagnetic interference, corrosion resistance, high accuracy, light texture, flexible and so on. According to the principle of Fabry-Perot cavity light interference, the fiber F-P cavity ultrasonic sensor is fabricated. The demodulation system of fiber optic ultrasonic sensor is built by using its sensing characteristics, and the demodulation analysis is carried out by using the collected ultrasonic signal. In this paper, the sensitivity of fiber F-P cavity ultrasonic sensor is studied. The main contents are as follows: 1) according to the multi-beam interference theory and sensing principle of F-P cavity. A fiber F-P cavity ultrasonic sensor is designed. The basic principles of intensity demodulation and phase demodulation are analyzed. The influence of the structure parameters of quartz diaphragm on the sensitivity and resonant frequency is analyzed. The effective radius and thickness parameters of quartz diaphragm of ultrasonic sensor are optimized by comparing the different structure parameters of diaphragm with ANSYS simulation software Workbench platform. Three fiber F-P cavity ultrasonic sensors were fabricated. The demodulation system of fiber F-P cavity ultrasonic sensor is developed. The hardware circuit of the system is designed in detail, and the DFB narrow band laser diode is designed. The selection of optical components such as low noise photodiode and optical fiber coupler, as well as the analysis of the interface of these optical devices and flange. Through the amplifier chip, power chip and AD acquisition chip selection. The amplifier circuit, power conversion module and A / D data acquisition module are developed, the demodulation system of fiber F-P cavity ultrasonic sensor is built, and the software of upper computer is developed. The host computer communicates with the demodulator acquisition module through the USB port. It has the functions of real-time data acquisition, storage database, different display modes of data, parameter configuration and performance analysis, etc. Upper computer acquisition function, data storage function, display function, etc.) using electronic pulse discharge to generate ultrasonic signal. The signal is collected and detected by fiber F-P cavity ultrasonic sensor and piezoelectric ceramic sensor, and the output voltage amplitude of the two sensors under the same PD source is obtained. The relationship between the output voltage amplitude of the sensor and the ultrasonic sound pressure is studied. The effects of the structural parameters and natural frequency of the sensor on the sensitivity are studied by the transverse contrast experiments of three fiber F-P cavity ultrasonic sensors. The influence of the damping of fiber F-P cavity ultrasonic sensor in different media on the sensitivity is studied. The performance of optical fiber sensor and piezoelectric sensor is compared.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212;TM41

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