【作者】 王美蓉；

【导师】 周王民；

【作者基本信息】 西北工业大学 ， 光学， 2005， 硕士

【摘要】 光纤电流传感器是一种集光纤传感技术、光电技术、非线性光学及信号处理技术等多个学科的理论和应用于一体的新型传感器。因其固有的特点和优势,这种电流传感器在电力工业中具有广泛的应用前景和良好社会经济效益。 传感材料的研究是光纤电流传感器中的一个重要问题。BGO晶体是一种优良的电光晶体,近年来被大量用于光学电压传感器,而将它用作电流传感器的研究却较少。本文通过理论分析和实验研究证实了BGO晶体用于电流传感器的可行性,为利用一块BGO晶体同时测量高压线上的电流和电压的技术奠定了基础。 本文的主要工作是在对BGO晶体的磁光特性进行了较深入研究的基础上,采用BGO晶体作为传感元件,设计了一种基于法拉第效应的混合型光纤电流传感器,并对其整体性能进行详细的研究。取得了以下研究成果: 首先,在理论分析BGO晶体磁光特性的基础上,利用倍频法测量了不同工作波长下BGO晶体的费尔德常数,获得了与理论相符的实验结果。同时根据BGO晶体费尔德常数随波长的变化关系曲线,通过对该晶体吸收系数的测量,得出了其磁光优值曲线。进而将BGO晶体的磁光特性与光纤电流传感器常用的几种磁光材料作了对比,结果表明BGO晶体适合用于光纤电流传感器。 其次,通过对传感器输出信号的特点分析,设计了纯模拟电路和智能光电系统两种光电检测与信号处理系统。其中纯模拟电路探测处理系统已用于本文电流传感器的实验研究。结果表明,该处理系统是完全可行的。 系统地讨论了基于BGO晶体的光纤电流传感器的基本结构,并设计了一种闭合磁环型的传感头。在此基础上建立了一套实验系统,对其性能进行了实验研究。结果表明,该系统线性良好、动态范围大,但存在一定的系统误差。 最后,对产生系统误差的因素和消除方法进行了详细地分析和讨论。对其中最主要的反射相移误差,在理论分析的基础上建立了其对电流传感器性能影响的数学模型,并对其进行了计算机仿真。 理论和实验都证明,基于BGO晶体的光纤电流传感器可以发展成一种性能优良的实用传感器。更多还原

【Abstract】 Optical fiber current transducers (OCTs) are new-style sensors based on the optical fiber sensing techniques, photoelectric techniques, nonlinear optics and signal processing techniques. Because of their natural characteristics and inherent advantages, OCTs have been widely used in electric power systems and have more economic benefits.Investigations on the sensing materials are very important issues for OCTs. Recently, BGO crystal as an excellent electro-optic material has been widely used in optical voltage sensor. However, there are few studies on utilizing BGO crystals for OCTs. The feasibility of using BGO crystals for OCTs has been demonstrated both theoretically and experimentally in this paper, which found the basis of the technique for measuring the current and voltage simultaneously.This paper mainly investigates a hybrid OCT, which utilizes a BGO crystal acting as sensing element. First of all, based on the theoretical analyses of the magneto-optical properties of a BGO crystal, the Verdet constants of a BGO crystal at different wavelengths are measured by employing the double frequency method. And the experimental results agree with the theoretical values. By combining the measured absorption coefficients with the relations between the Verdet constants and light wavelengths, the magneto-optical figure of merit of BGO crystal is presented. Additionally, the magneto-optical properties of BGO crystal are compared with that of some magneto-optical glasses usually used for OCTs. The results show that BGO crystals are suitable for fabricating OCTs.Secondly, by analyzing the output signals of the OCT, we have designed two types signal-processing systems: a pure analog electric circuit and an intelligent opto-electric system. Of which, the pure analog electric circuit has already been used in the experiments. And the results demonstrate that the system is feasible.Additionally, an OCT based on the use of a BGO crystal as a magnetic field sensor together with a ferromagnetic core with an air-gap as a field concentrator is designed and experimentally demonstrated. The results show that the system possesses a good linearity and a large dynamic range. However, there exist certain errors between the measured and the real values.Finally, the origins of the errors and the methods for omitting the errors are analyzed and discussed in detail. The influences of the phase shift caused by the reflection, which are the main resources of the errors, are theoretically analyzed and numerically simulated.The results of theoretical analyses and experiments demonstrate that the hybrid OCT based on BGO crystal can be developed into a practical OCT with good performances.更多还原