ZHAO Yong1, GUO Liang2, CHENG Yong-hong2. Design of Measurement Circuit for Weak DC Signal[J]. High voltageapparatus, 2008, (4): 356-358.DOI:
微弱直流信号测量电路设计
摘要
为了提高XLPE电缆直流法在线监测的测量精度
需对微弱直流信号进行测量。笔者介绍了XLPE电缆直流法在线监测系统中微弱直流信号测量电路的设计方案
分析和比较了几种初级放大电路的性能
研究了测量电路中的几个关键模块设计。试验结果表明
该测量电路的设计方案可以较精确地测量约为1nA的直流信号
平均误差约为2%
能够满足监测系统对信号的精度要求。
Abstract
The measurement of weak DC signal is the key technique for on-line DC monitoring system with XLPE power cables to improve its measurement accuracy.Designs of the key units in measuring circuit for weak DC signal and a design of digital filter were developed.The measuring circuit was examined
and the results of examination show that the measuring circuit can detect 1 nA DC current
and the average error is less than 2%
which agrees the requirement of on-line DC monitoring system with XLPE power cables for DC signal measurement.