Effects of the polarizer parameters upon the performance of an optical current sensor

Extinction ratio is an important parameter of a polarizer, and the bias angle of the polarizer used in optical current sensing systems is also an important adjustable parameter. Both of them can certainly affect the performance of the sensing systems. In this paper, the effects of the extinction ratio and bias angle error of polarizers upon the output characteristics of an optical current sensor are investigated theoretically and experimentally; some useful results are given for the optical current sensor researchers and designers.     

Wavelength dependence of the sensitivity of a bulk-glass optical current transformer

The wavelength dependence of the sensitivity of a bulk-glass optical current transformer is theoretically analyzed, simulated numerically and verified experimentally. The results show that the wavelength dependence will cause obvious sensitivity fluctuation of the system because of the existence of the dispersions of the reflection-induced retardance, Verdet constant, and the linear birefringence inside the bulk-glass current sensing head. Therefore, it is necessary to stabilize the driving current and the ambient temperature of the optical source of the sensor or compensate the harmful effects caused by wavelength variation. These results might be useful for researchers and designers working in the optical current transformer techniques area.     

Effect of dispersion of linear birefringence upon the sensitivity of an optical current sensor

The dispersion properties of the linear birefringence inside the glass current sensing head of a bulk glass optical current sensor and its effect upon the sensitivity of the sensor are theoretically analyzed and simulated with a computer. The investigation results show that the effect is small enough to be ignored, although it can certainly affect the scale factor of the system slightly. These results might be useful for the researchers and designers working in the optical current sensing techniques area.     

Faraday mirror-typed optical current transformers and its theoretical analysis

A Faraday mirror-typed optical current transformer (OCT) design with turn-back optical paths is proposed to overcome the harmful effects of the linear birefringence inside bulk glass current sensing head, which can double the sensitivity and improve the state of polarization of the system output. The theoretical analysis of the working principle, the simulation of the polarization state of the output light beam and the comparison between it and the OCT with polarization preserving total reflection (PPTR) layers are presented. The results show that this design has a good suppressing effect on the degeneration of the polarization state of the output light, which has certain reference significance on the performance improvement of the present bulk glass OCT, and the development of practical OCTs.     

Joint effect of dispersions of reflection-induced retardance and Verdet constant upon the sensitivity of an optical current sensor

The dispersion properties of the reflection-induced retardance of polarization-preserving reflecting medium layer and the Verdet constant of the ZF-7 optical glass and their joint effect on the sensitivity of a bulk glass optical current sensor are theoretically analyzed taking the Jones’ Matrix as a mathematical tool and using simulation with a computer. The investigation results show that the dispersions will significantly affect the scale factor of the system. Therefore, it is necessary to stabilize the driving current and the ambient temperature of the optical source by some technical means to ensure the wavelength stability. These results might be useful for the researchers and designers working in the optical current sensing techniques area.     

测量脉冲大电流的四光路光学电流传感器技术

 在传统光学电流传感器技术的基础上，提出了一种四光路光学电流传感器，其通过四路输出信号可准确确定偏转角，使电流的测量范围不受正弦函数的单调性的限制，从而提高了电流的测量范围。配合四光路结构，提出了新的反正切函数数据处理方法，其不存在角度不灵敏区、可纠正原始数据的缺陷，从而提高了测量精度。实测了充电电压为4.5 kV、电容为50 μF和导线有效穿过磁光探头14次的快开快门的总短路电流，其峰值达85 kA，与理论值87 kA能较好地吻合，从而证明了四光路光学电流传感器可有效地测量脉冲大电流。     

四角状ZF-7玻璃双层光路电流传感头研究

利用线偏振光在ZF-7玻璃中多次全反射构成块状四角双层光路电流传感头.本文分析了入射面相互垂直的相邻二次全反射的P与S分量之间的位相及其相互抵消.对该传感头进行了实验测试.     

光学电流互感器传感头色散特性对系统灵敏度影响研究

以琼斯矩阵为数学工具,利用理论分析和计算机仿真的方法研究了块状玻璃光学电流互感器传感头的色散特性对系统灵敏度的影响,并进行了实验验证.在光学电流互感器系统中,光源的驱动电流与环境温度改变,都会造成光源峰值波长移动.而在传感头中主要是由单层保偏反射膜的反射相移、光学玻璃的Verdet常数以及光学玻璃内的线性双折射这三个因素的色散特性,使得光学电流互感器的灵敏度随光源波长的变化而改变.研究结果表明,这种色散特性会对输出曲线的尺度因子产生明显的影响.因此,光源的恒温控制与光源驱动电流的恒流控制是必要的.本研究结果可为光学电流互感器的研究设计人员提供有用的参考.     

混合型大电流光纤传感器的研究

本文叙述了混合合型大电流光纤传感器的工作原理及制作方法.以LED作光源、PIN作接收、火石玻璃为磁感应材料、多模光纤作导光波导的混合型大电流光纤传感器,用于监视高压电网系统中的电流.适用范围10~2～10~4A,精度±0.5%.     

Development of bulk-optic current sensor using glass ring type faraday cells

Bulk-optic current sensors have been developed for electric power systems. This current sensor has a glass ring type Faraday cell, where a light beam circulates around a current-carrying-conductor to precisely measure the current. Fundamental performances and practical applications are described.     

一种完整测量膜片法拉第效应和损耗的方法

提出了一种能完整测量零锁区激光陀螺法拉第偏频组件中旋光膜片的法拉第旋光效应和超低损耗的方法和自动测量系统.该方法利用双光路正交分解平衡测量原理,通过测量两柬光光强平衡时起偏器的偏振方向来确定旋光膜片的法拉第转角和超低损耗.测量结果表明:系统对法拉第转角的测量分辨率小于0.9",损耗测量分辨率为10 ppm,环境温度的波动对法拉第转角的测量变化很小,但对膜片超低损耗测量影响很大,温度变化8.1 K,膜片损耗测量值变化一个周期.实验及结果证明,该系统能满足超高精度测量的要求.     

Optical current transducers using flint glass fiber as the faraday sensor element

This paper describes development of the optical current transducers using flint glass fiber as the Faraday effect sensing element. Excellent polarization properties of the fiber with low birefringence are described, and the design and test data of a current transducer using the fiber manufactured for use in electric power facilities are reviewed. Experimental results on flexible characteristics of a scheme with round trip light transmission in the fiber is also reported.     

一种完整测量膜片法拉第效应和损耗的方法

提出了一种能完整测量零锁区激光陀螺法拉第偏频组件中旋光膜片的法拉第旋光效应和超低损耗的方法和自动测量系统.该方法利用双光路正交分解平衡测量原理,通过测量两束光光强平衡时起偏器的偏振方向来确定旋光膜片的法拉第转角和超低损耗.测量结果表明：系统对法拉第转角的测量分辨率小于0.9″,损耗测量分辨率为10 ppm.环境温度的波动对法拉第转角的测量变化很小,但对膜片超低损耗测量影响很大,温度变化8.1 K,膜片损耗测量值变化一个周期.实验及结果证明,该系统能满足超高精度测量的要求.     

基于声发射传感器的高温超导线圈临界电流的研究

用经验失超判据Ec=1μV/cm可以对高温超导线圈在直流情况下的临界电流进行检测,但对于高温超导线圈交流时的临界电流还没有一个标准.利用声发射传感器对高温超导线圈的交流临界电流进行了初步研究,并把结果与直流临界电流进行了比较,结果表明在低于直流临界电流时,声发射传感器获得了明显改变的声信号,即高温超导线圈的交流临界电流...     

基于法拉第磁光效应的电流方向测量研究

为解决法拉第磁光效应测量电流方向问题,利用法拉第效应原理搭建了测量电流方向的实验系统,研究不同方向电流作用下的磁致旋光特性,测量了不同方向的电流与光传播方向、光旋转角度之间的关系,实验结果表明:迎着光观测,出射线偏振光的旋光方向表现为右旋时,相应的电流方向沿光传播方向;当出射线偏振光的旋光方向表现为左旋时,相应的电流方向与光传播方向相反。实验结果与理论相符,对指导设计同时可以测量电流大小和方向的光学电流互感器等法拉第磁光器件具有重要的应用价值。     

磁场对载流线圈的作用

讨论了磁场对于载流线圈的合作用力、合力矩、磁力作功公式和载流线圈在外磁场中的相互作用能，以及带电粒子在一对励磁线圈之间的往复运动。     

A novel optical polarimeter based on the signal width measurement of the waveform

For the optical polarimeter based on the structure of polarizer–Faraday modulator–analyzer, a novel method of optical rotation measurement was proposed by the waveform analysis of optical intensity signals. The calculation method of the optical rotation was provided by measuring the signal width of the waveform. Furthermore, the optical rotations of sugar solutions with different concentrations were measured by this method, and the fitting degree of obtained fitting curve is 0.9996. This showed that this method was effective.     

起偏器参量对光学电流传感器性能的影响

以琼斯矩阵为数学工具,利用理论分析、计算机仿真和实验研究的方法,考察了偏振片的消光比和预偏角误差对光学电流传感器输出特性的影响.研究结果表明,上述偏振片参量均可在光学电流传感器的输出中引入直流分量,并使尺度因子发生一定的改变.当最终输出信号用交流电表度量时,输出信号中引入的直流分量可被交流电表中自带的隔直电容滤除,尺度因子的改变可用后续信号处理电路中的放大单元矫正.本研究结果可为光学电流传感器的设计人员提供有用的参考.     

Imperfection errors in glass block faraday effect current sensor

Theoretical analysis of measurement errors caused by the imperfection of the sensing optical loop in a glass block Faraday effect current sensor has been presented. The experimental results with the fabricated sensor which was designed to achieve a closed homogeneous and isotropic optical path show the importance of the perfectly isotropic and closed loop, in accordance with the theoretical consideration.     

Optimal sensing of current based on an extrinsic Sagnac interferometer configuration

The theory and experimental verification of an optical current sensor based on an extrinsic Sagnac interferometer configuration is presented. Superior performance with regard to current sensitivity and input/output linearity, and simple installability of the sensor makes it very suitable for remote current sensing in power distribution applications.