A method to eliminate birefringence of a magneto-optic AC current transducer with glass ring sensor head

This paper reports a novel method of assembling a magneto-optical current transducer, which can eliminate both thermal transient and construction-caused birefringence to a large extent. The method is simple and practical, and needs no temperature compensation in signal processing. With a closed aluminum shell, sensing material buffers and flexible construction, the accuracy of the compromise-developed MOCT with glass ring sensor head was better than 0.3% over a temperature range of -30 to 70/spl deg/C and current range from 100 to 2400 A. The field testing verified this performance.