超辐射发光二极管（SLD）光源作为光纤电流互感器光路中唯一的有源器件, 其长期运行稳定性直接影响着互感器的性能。文章主要从SLD出光功率衰减对光纤电流互感器输出固定偏置、变比和相位的影响机理进行理论推导, 结果表明在非理想数字闭环情况下, 随着光功率的衰减, 互感器输出固定偏置增大; 同时光功率的衰减会导致电流互感器的信噪比降低, 进而导致互感器输出的比值误差和相位误差增大。并对理论结果进行了实验验证, 实验结果符合理论分析, 其中光功率衰减对互感器相位误差的影响最大。

SLD is the only active device in the optical path of the fiber optical current transformer, and its long-term stability directly affects the performance of the transformer. This paper mainly studies the influence of SLD’s power attenuation on the fixed bias, scale factor and phase of transformer’s output. Research results show that the fixed offset of the transformer’s output increases with the attenuation of SLD’s power. Besides, power attenuation deteriorates the signal-to-noise ratio of the transformer, which leads to the increase of the ratio error and phase error. The theoretical results are verified by the experiments. Furthermore, the power attenuation has most influence on the phase error.