外电流杂散磁场引起GTA误差的机理分析

由于外电流产生的杂散磁场会改变线路上的大电流互感器（GTA）铁心的工作状态,使GTA产生附加误差,准确度下降,甚至引起GTA铁心饱和或者失效.基于等值电路模型和磁路模型分析了外电流对GTA的误差机理,研究了外部电流对电流互感器误差性能的影响,并对泄漏磁场造成GTA误差进行了实验计算,根据干扰机理分析结果提出了抗干扰应依据的基本原则.

The working condition of large current transformer core will be changed by stray magnetic fields generated by external current, so that GTA will generate the additional errors, which decreases the accuracy and even leads to core saturation or failure of GTA. Based on the models of equivalent circuit and magnetic circuit, the error mechanism of GTA caused by exter- nal current is analyzed, and the influence of external current on error performance of current transformer is studied. In addi- tion, the experimental calculation is carried out for GTA error caused by leakage magnetic field. According to the interference mechanism, the basic principles of interference rejection are proposed.