Foreign countries began to study optical fiber current sensors in 1960s. Research institutions in the United States, Japan and Western Europe and some electrical instrument companies have done a lot of work in this field, such as the National Institute of Standards and Technology, Bell Laboratories, Japan's Academia Sinica, NEC, Toshiba, Panasonic and the Royal Swedish Institute of Technology. By the early 1980s, optical fiber current sensors began to enter the industrial trial stage. 1986, the Tennessee Valley Power Administration (TVA) installed the first current transformer for single-phase high-voltage optical measurement at the power marshalling station of Chkamauga dam, which was dismantled after more than two years of reliable operation. The conventional voltage transformer in the power station provides voltage for OCT, and the change is only 0.08% compared with the reference system in one year's kWh measurement. According to various predetermined conditions such as load, temperature, humidity and electromagnetic interference, the due tasks have been completed. In substation environment, it shows stable and accurate performance. The optical current sensor using Faraday effect is in the exploration stage in China. During the "Sixth Five-Year Plan" period, since the seminar on the application of laser industry held in Shanghai in September 1982, many units have successively carried out research in this field, and the Eighth Institute of CLP, Shanghai Silicate Institute, Shanghai Metallurgical Institute, North China Electric Power Bureau, Beijing Institute of Chemical Technology, Tsinghua University and Huazhong University of Science and Technology have all achieved certain results.

A few days ago, the new optical fiber current sensor-"XDGDL-1optical fiber current sensing system" independently developed by Hubei Xundi Technology Co., Ltd. passed the appraisal of scientific and technological achievements hosted by Hubei Science and Technology Department. Experts attending the appraisal meeting believe that the project has achieved important scientific and technological achievements with independent intellectual property rights, the overall technology is at the international advanced level, and the project products have filled the domestic gap, which is of great significance to the large current DC measurement in China's metallurgical, chemical and other electrolytic industries. Over the past year or so, the products of this project have been tested in different environments and ranges (minimum range of 40kA, maximum range of 400kA) in typical domestic enterprises such as Henan Wanji Aluminum, Henan Shenhuo Aluminum, Jiangxi Copper, and Zhuzhou Chemical Industry of Zhongyan Group. After on-site testing and assessment, the performance is stable and reliable, all technical indicators meet the design requirements, and some indicators and functions are better than similar foreign products.