Real-time current overhead lines load current Monitoring using GMR sensors

We have developed a physical test facility to estimate the overhead line load current using a non-contact GMR magnetic sensor. Two GMR sensor heads were used to measure the magnetic field of the overhead power lines. The off-the-shelf GMR sensors were calibrated to determine the sensitivity, a factor to convert the analog voltages from the sensor to magnetic fields. Alongside the GMR sensor, Hall effect current sensors were installed in the facility to capture the current data, which serves as a reference load current data. A modified mathematical model based on the Biot-Savart theory was the basis for estimating the overhead line current from GMR sensor data. The calculated and measured currents from the Hall effect sensor were compared to determine the estimation accuracy. Finally, an application was developed using the MATLAB program to monitor the measured and estimated magnetic field and load current data in real-time.