Temperature Compensation in Full Optical Fiber Current Transformer using Signal Processing

Error caused by temperature change is one of the major reasons for restricting the promotion of Full Optical Fiber Current Transformer (FOCT) at present. This article analyzes how the change of temperature makes impact on the parameters of optical devices, such as the original phase of quarter-wave plate and the Verdet constant of the fiber. After the experimental data are sampled in a temperature range from +20 degrees C to +70 degrees C, the relational model of error and temperature can be set up by adopting least-square method. After compensation based on this model, error could be decreased; meanwhile the precision of FOCT could be improved. Indeed, the experimental results verify that the accuracy of FOCT can be improved four times, compared with the original output without compensation. This method of compensation is quite effective to reduce the temperature influences on the FOCT to improve the accuracy.