Digital Measurement of Line Current with the Use of Virtual Short Circuit Method

Vladimir Vujicic, Aleksandar Radonjic, Dragana Naumovic-Vukovic, Nemanja Gazivoda, Platon Sovilj

Abstract

The paper describes a method of very accurate measurement of line current using a current transformer (CT) in a virtual short circuit. The key systematic error, amplified error due to offset of operational amplifier that leads CT in a virtual short circuit, is easily calculated using a stochastic digital measurement method and eliminated from measured RMS value of line current. Since the 2-bit stochastic digital measurement method is defined using a very simple hardware which has a small number of sources of systematic error, sources are easily identified and it is described how to eliminate these errors. A complete measurement scheme of line current is presented and applied in quadruple three-phase power analyser with MM4 type designation. MM4 is a key component of the redundant measuring system in the Electric Power Grid of Serbia.

Keywords

digital stochastic measurement, line current, current transformer

Download

IMEKO-TC4-2017-051.pdf

DOI

-

IMEKO TC

TC4 - Measurement of Electrical Quantities

Back to the proceedings