Description
With accelerating Smart Grid and automated Smart Building technologies, there is an ever-increasing demand for non-invasive, networked load monitoring. Magnetometers leveraging Giant Magnetoresistance (GMR) can be used to measure electrical currents via their inherent magnetic fields. Research is conducted to characterize these sensors and investigate their usefulness in a wireless embedded system for the purposes of energy management in power distribution equipment. An example embedded system design is proposed as a non-intrusive power monitoring solution. The goal of such a system is that it can be installed without opening the electrical equipment or removing the faceplate, so that power management can be employed without requiring qualified electricians. This work investigates realistic scenarios for employing GMR sensors in power distribution load centers with multiple circuits. Research is done to assess how multiple current sources create magnetic fields in panelboards, and how an array of GMR-based magnetic field sensors may be used to capture power load events. Methods for collecting and processing multi-channel sensor data are discussed, particularly techniques for eliminating signal crosstalk between the channels. Through several experiments on two purpose-built testbeds, a calibration method is developed for the sensor array. Using the calibrated sensor array, measurements of electrical currents are made with a percent error ranging from 0.82% to 15.88% for active loads.
