The Wireless Transmission Design of a Novel Electronic Current Transformer

摘要

This study presents a novel electronic current transformer (ECT), which is based on the Hall current transformer (HCT), and a wireless transmission system. The novel ECT is aimed to be used in both measuring and protective current transformers, and the design of the wireless communication makes ECTs more flexible for current measurements at different current levels in power systems. The novel ECT can be separated into three main circuits, including sensing signal processing circuit, analog-to-digital conversion circuit, and wireless circuit. Firstly, the scale of measured current is classified into small current, middle current, or large current. Then, analog to digital converter digitize the classified signal. Finally, ZigBee device transmits the signal wirelessly to the data acquisition/monitoring system. If electric currents are detected as small or middle current levels, I_(rms) and the reconstructing current proposed by this study will be sent to the monitoring system. Moreover, if electric current is detected as large/fault current level, an alarm will be sent immediately to monitoring system, and 10 cycles of the actual current will be sent later. Besides, LabVIEW is used to build the data acquisition/monitoring system and the measurement result shows that the percentage current error between the transmitted signal from the ECT and the original signal is below 0.15%.