Research and Design of a New Kind of Optical Current Transducer

This paper introduces a new kind of optical current transducer and its application in measuring high voltage DC and AC in power system. To solve the long-term operating stability and the steady state metering accuracy which influence the practical course of OCT, this paper presents a new method which combines the lock-in amplifier in slight photo-electric signal detection and a new higher stability sensor, introduces the principle and the design of the optical sensor on solenoid collecting magnetic field, and analyzes the characteristics of signal and noise in OCT. This paper also describes the principle and the performance of the lock-in amplifier and its application in OCT in order to improve the output SNR. The test results indicate that under the steady state metering accuracy has already reached class 0.2, the long-term stability has improved, and the designed OCT has achieved the requests in power system.