A Fault Diagnosis System of All-Fiber Optical Current Transformer with Correlation Detection

Abstract

All-fiber optical current transformer (FOCT) based on Magneto-optical Faraday effect plays a pivotal role in current metering and protection of smart grid. However, the fault diagnosis of FOCT is one of the most critical issues to be solved. In order to ensure the proper functioning of FOCT, a fault diagnosis system is presented by monitoring the intensity variation of the light interference with Square wave bias modulation of FOCT, which is measured by digital signal processing unit using correlation detection technology. Afterwards, the faulty types of FOCT are recognized by the amount of the optical power variation. The experimental results show that the system can effectively detect these kinds of fault types, such as the broken of optical fiber, the increasing loss of optical fiber and the breakdown of light source in FOCT.