Real-time Load Current Monitoring of Overhead Lines Using GMR Sensors

TL;DR

This paper demonstrates the use of GMR sensors for non-contact, real-time monitoring of overhead line currents, comparing their performance to traditional Hall sensors and developing a framework for accurate current estimation.

Contribution

It introduces a novel application of GMR sensors for overhead line current measurement and develops a mathematical and visualization framework for real-time monitoring.

Findings

GMR sensors achieved 64.64% to 91.49% accuracy in current measurement.

The system enables real-time visualization of phase currents.

Potential improvements could enhance sensing accuracy.

Abstract

Non-contact current monitoring has emerged as a prominent research focus owing to its non-intrusive characteristics and low maintenance requirements. However, while they offer high sensitivity, contactless sensors necessitate sophisticated design methodologies and thorough experimental validation. In this study, a Giant Magneto-Resistance (GMR) sensor is employed to monitor the instantaneous currents of a three-phase 400-volt overhead line, and its performance is evaluated against that of a conventional contact-based Hall effect sensor. A mathematical framework is developed to calculate current from the measured magnetic field signals. Furthermore, a MATLAB-based dashboard is implemented to enable real-time visualization of current measurements from both sensors under linear and non-linear load conditions. The GMR current sensor achieved a relative accuracy of 64.64% to 91.49%, with most phases above 80%. Identified improvements over this are possible, indicating that the sensing method has potential as a basis for calculating phase currents.