传感器技术是大数据技术在电力系统应用的基础,而现有光学电流传感器(optical current sensor,OCS)基于马吕斯定律采用光强检测模式实现对法拉第旋转角的测量,导致非线性测量、动态范围小、易受线双折射和温度影响等问题。该文提出一种用晶体劈将法拉第旋转角转换为条纹的位移,并通过数字图像采集单元测量位移量,实现法拉第旋转角大范围线性测量的OCS设计方法。实验结果表明,相比传统光强检测模式,采用成像测量模式可使OCS具有光功率无关性、动态测量范围大、线性测量等优点,同时降低了温度对测量结果的影响。
Sensor technology is the foundation of big data applications in power system. The existing optical current sensor (OCS) based on Malus law and its light intensity detection mode has some defects of small dynamic measurement range, big temperature drift and linear birefringence. In this paper, a new type of OCS which can achieve linear measurements of a wide range Faraday rotation angle was presented. It used crystal wedge to convert Faraday rotation angle to displacement of light lines, image acquisition system captured the spot, and calculate the displacement. Compared with light intensity detection mode, the experimental results show that imaging mode enables OCS with optical power independent, large dynamic range and linearity measurements. Temperature drift on the measurement results is also reduced.