中文摘要：

为降低电子式电流互感器（ECT）的暂态误差、提高稳态电流的测量准确度,提出了一种应用于罗氏线圈ECT信号采集系统的压频变换器模数混合积分器（VFC-ADI）方法。对罗氏线圈输出信号进行压频数值转换,由脉冲计数器完成数值计数,微处理器对计数值处理后得出被测电流的积分波形。选取VFC芯片AD7742进行仿真分析,仿真结果显示VFC-ADI方法能准确地反映一次侧暂态电流波形。对罗氏线圈ECT暂态故障电流及稳态电流进行试验测试,结果表明VFC-ADI方法能准确反映暂态故障电流特征;对于稳态电流测试,比差的变化范围为-0.15%～0.15%,角差的变化范围为-1′～1.5′,其输出值完全满足0.2 s级基本准确度测试要求。VFC-ADI方法在模数转换过程中实现了积分功能,数据处理结果表明其更接近于理想积分器。

英文摘要：

A method based on VFC-ADI（VFC-based Analog-to-Digital Integrator） is proposed for the signal acquisition system based on ECT（Electronic Current Transformer） with Rogowski coil to reduce the transient error of ECT and enhance its steady-state current measuring accuracy. The output voltage of Rogowski coil is converted into pulse string,the pulse quantity is then recorded by the pulse counter,and the pulse quantity is finally processed by microprocessor to obtain the integral waveform of measured current. VFC AD7742 is selected for the simulative analysis and the simulative results show that the proposed method accurately reflects the primary current waveform. The transient and steady-state currents of ECT with Rogowski coil are tested and results show that,the proposed method accurately reflects the transient characteristics of fault current;the ratio difference from-0.15% to 0.15% and the angle difference from-1′to 1.5′ meet the basic accuracy requirements of class 0.2 s. The proposed method realizes the integral function during the AD conversion and the data processing results show VFC-ADI closer to an ideal integrator.