Magnetic-collecting Optical Current Sensor based on Magneto-optic Crystal

In this paper, we propose a magnetic-collecting optical current sensing system, which is mainly composed of magneto-optic crystal and magnetic-collecting ring for on-line current monitoring. An optical sensing platform has been built to measure the 50Hz AC current, and the sensitivity and resolution of magneto-optical sensors based on two different magneto-optical crystals are studied. The results show that the sensitivity of the ferromagnetic yttrium iron garnet crystal (YIG) is 140 times higher than that of the paramagnetic Terbium Gallium Garnet crystal (TGG), and the measurement accuracy can be improved to 0.25A, which can meet the requirements of current measurement in the power system.