ECT采集单元积分回路的暂态特性改进及其检测系统研发

Improvement of transient characteristics and development of a testing system of an integration circuit in ECT acquisition unit

电子式电流互感器采集单元的暂态误差及拖尾现象影响继电保护设备在故障发生时正确动作。通过仿真验证了过零点暂态误差是拖尾现象产生的根本原因,且这种误差是由罗氏线圈的电路积分环节造成的,从原理上无法完全消除。因此,提出提高硬件积分回路的衰减时间常数以及动态启用软件积分的积分衰减算法分别改进对应类型采集单元的暂态传变特性。为了对改进后的采集单元的暂态特性进行测试,提出采用连续时域微分技术来模拟罗氏线圈信号的输出,通过故障相位补偿同步技术实现暂态误差的测试。所提方法为基于罗氏线圈原理的电子式电流互感器的工程应用及采集单元更换提供了一套完整的检测手段。

Transient error and tailing of an ECT acquisition unit affects the correct operation of relay protection when the fault occurs.This paper simulates and verifies that the zero crossing transient error is the root cause of the tailing phenomenon,and this error is caused by the circuit integral par of the Rogowski coil.In principle this cannot be completely eliminated.Therefore,we propose improving the transient transmission characteristics of this kind of acquisition unit by increasing the attenuation time constant of the hardware integration circuit and enabling the integration attenuation algorithm of the software integration dynamically.In order to test the transient characteristics of the improved acquisition unit,we propose a continuous time-domain differential technology to simulate the output signal of the Rogowski coil,and realize the measurement of transient error by the synchronous technology of the compensating fault phase.When undertaking an engineering application of ECT based on the Rogowski coil or replacing the acquisition unit,it can provide a complete set of test means.