商用化的全光纤电流互感器(FOCT)的误差一般要求小于0.2%，传感头是决定该类传感器测量准确度的关键因素。论述了FOCT的光路结构、工作原理及研制难点，分析了传感头对FOCT性能的影响，并对传感头的设计、制作及封装制作工艺进行了深入研究。通过选择合适的材料和工艺方法，可避免各种负面效应对FOCT的不利影响，获得具备优异的环境适应性、可靠性和稳定性的传感头，试验结果表明，通过该方法实际制作出的传感头提高了FOCT的性能，使其满足了0.2 S级测量用电子式电流互感器的准确度要求。

The error of commercial Fiber Optic Current Transducer(FOCT) must be less than 0.2%, the sensing head is a key factor for high-accuracy current sensing. The topology, operational principle and difficulties of fiber optic current transducer were introduced, and the sensing head affecting the performance of fiber optic current transducer was analyzed. The design, fabrication and encapsulation of sensing head were studied. The improved sensing head that can avoid all kinds of negative effects was manufactured by using suitable material and method, which has excellent environment adaptability, reliability and stability. The experimental results show that the measurement precision of fiber optic current transducer is improved by using the improved sensing head, and the FOCT can satisfy the accuracy requirements of the 0.2 S class measuring electronic transducer, meeting the requirements of digital substation.