A design scheme of high precision electronic current transformer is proposed, the small signal is processed specially with the Programmable Gain Amplifier (PGA), and the noise interference of small signals and the measurement error of AD itself are eliminated. The accuracy of small signal acquisition is improved. At the same time, it uses multi sampling channels conversion method to improve the overload ability effectively. Phase and amplitude are corrected by using digital method which enhances system anti-interference ability. The output digital signal follows IEC61850-9-2 standard, and can be used for measurement and protection. The design is tested by experiment. Precision reaches to 0.1s standard and has 50 times overload ability, and the EMC characteristics is excellent.%提出了一种新型的高精度电子式电流互感器采集器的设计方法,采用了可编程增益放大器( PGA),对小信号进行特殊处理,消除小信号时的噪声干扰和AD本身的量化误差,提高小信号采集的精度.同时通过多个采样通道的切换技术,有效地提高了采集器的过载能力.采用数字方法进行幅值和相位的校准,提高了系统的抗干扰能力.输出的数字信号遵循IEC61850-9-2规约,能够同时用作保护和测量.设计通过验证,精度达到了0.1S级,具备50倍过载能力,并且具有较好的电磁兼容特性.
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