【作者】 董理科；

【导师】 滕峰成；

【作者基本信息】 燕山大学 ， 电力系统及其自动化， 2011， 硕士

【摘要】 在现代工业中,电气设备运行异常或发生故障多伴随着温度的异常变化。配电室的高压开关柜、电缆和母线都是重要的电气设备。在设备长期运行过程中,电缆、母线接头以及开关柜中的动、静触点结合处等部位容易因为局部温度过高引发事故。一旦发生电气设备安全问题,将造成巨大的生命和财产损失。发生接头过热的配电设备大多为10 kV以上的高压设备。而传统的电信号传感器需要外加电源,且易受电磁干扰,不能满足实时监测的需要,而光纤光栅传感器为无源器件,采用波长编码、可测参量多、测量精度高、复用能力强、耐高温、抗电磁干扰、本质安全,是监测高压配电设备过热故障的最佳选择。本文研究内容主要包括:首先,阐述了光纤光栅传感特性的数学模型和基本原理,利用耦合模理论对光纤Bragg光栅的光谱特性以及Bragg光栅对应变和温度的传感机理进行了分析,采用毛细钢管对Bragg光栅的封装技术进行了研究。其次,介绍并比较了光纤光栅的解调技术,针对高压配电室线路密集的问题,设计了时分复用加波分复用解调系统。采用此解调技术的温度监测系统可以同时监测多个配电室内母线、电缆及高压开关柜的多个接头的温度。并设计了相应的光电转换及放大电路及FFP-TF锯齿波扫描电压信号发生电路,通过仿真及实验验证了该系统方案的可行性。在此基础上,运用一般多项式拟合算法和高斯公式拟合算法对理想条件下的光栅反射谱和光纤Bragg光栅中心波长检测实验系统所采集的实验波形进行了寻峰运算,并对算法的运行结果进行了比较,相同条件下,高斯公式拟合法的寻峰精度更高。进行了FBG传感器的温度特性实验,结果表明利用三次多项式拟合算法比线性拟合和二次多项式拟合能够更有效地提高测量精度。最后,进行了传感器的24小时温度测量实验。更多还原

【Abstract】 In modern industry, failure and break down of electrical equipments usually show abnormal temperature. High voltage switch cabinet, electric cable and busbar in power distribution room are all important electrical equipments. In the long time of processing, contacts of electric cable,busbar and junctions between rest contact and movable contact of switch cabinet cause accidents which results in a lot of damage and loss of life and property because of high temperature. But traditional methods of temperature measurement fall behind and the function is so single that can’t meet the need of real-time monitoring of the high voltage electrical equipment’s temperature.The fiber grating sensor is the best choice for temperature monitoring of high voltage distribution equipments.This research includes:Firstly, the basic theory of fiber grating properties is expatiated, spectral characteristics of uniform-period fiber Bragg grating and the sensing principle of FBG under temperature and strain using the coupled-mode theory are analyzed. Steel capillary package method of fiber Bragg grating is studied.Secondly, wavelength demodulation technologies of FBG are introduced. In view of dense and messy lines in the high voltage power distribution room, a wavelength-division multiplexing plus time-division multiplexing demodulation method is designed. The demodulation system, including the photoelectric conversion and amplifier circuit, FIR filter, and FFP-TF scanning voltage generator can monitor the temperature of more than one root of a large number of cable joints. The feasibility of the system is approved by simulation and experiment.On this foundation, this paper detects peaks of the theoretical and experimental reflective spectrums using general polynomial fitting algorithm and Gaussian fitting algorithm. Gaussian fitting algorithm is proved to be the best by simulation and experiment.Experiment on temperature characteristic of FBG is carried on and general polynomial fitting algorithm is applied to the result. And the cubic polynomial fitting algorithm is proved to enhance the precision of the modulation system effectively. At last, temperature measure experiment of 24 hours is carried on.更多还原