光纤电流互感器平均波长漂移变比误差

全温条件下(-40~60℃)测量精度误差较大是影响光纤电流互感器实用化进程的主要原因之一。传感光纤的维尔德常数随光纤内光波平均波长变化,导致系统输出变比漂移,从而降低系统的测量精度。理论分析了光谱平均波长与系统输出变比之间的关系,并通过实验验证了关系式的准确性。分别对光纤电流互感器光路各组成器件对通过光平均波长的影响进行了分析,实验测量了变温条件下平均波长变化的趋势以及程度。提出了起偏器与延迟光纤在变温条件下对平均波长影响的自补偿方案,有效的减小了传感光纤中平均波长的漂移程度。保证光纤电流互感器在变温条件下到达0.2 s级精度要求。同时为适应更高测量精度应用场合提供了参考。

Ratio error of all fiber optical current transformer caused by mean wavelength,s fluctuation

Substandard ratio error under full temperature (-40-60℃) is one of the factors that restrains the practical application of domestic All Fiber Optical Current Transformer(FOCT). The Verdet constant of the sensing fiber changes with the fluctuation of mean wavelength when the light goes through. Then the output ratio is influenced which decreases the accuracy of the system. The relation between the fluctuation of mean wavelength and system ratio error was analyzed thoroughly and validated experimentally. Also, influence on the mean wavelength caused by the entire optical components was theoretically analyzed, and the degree of influence and the variation trend were experimentally measured. A method was put forward to make the polarizer and the fiber delay line have a temperature self-compensation on the variation of mean wavelength, and thus the change of mean wavelength was reduced. While the 0.2 s class accuracy requirement is guaranteed, the impact can be lowered as much as possible.