High-Voltage Power-Line Conductor Anomaly Detection Using Magnetic Field

This paper introduces a contactless, fully passive approach for locating faults in transmission line conductors. The method relies on the magnetic fields generated by the line current and captures them using low-cost, three-axis magnetic sensor integrated into a custom-designed drone payload. Unlike traditional inspection techniques, the proposed system performs rapid, multi-position magnetic scanning around the conductors within a short time window. By analyzing the spatial variations and temporal signatures of the measured magnetic field, the method can detect and characterize both external and internal anomalies, including potential structural degradations or irregular current distributions. Identified anomalies can be georeferenced accurately using the RTK-enabled GPS of the drone, allowing operators to determine their precise position along the transmission line. This capability supports targeted, close-range inspections and greatly enhances both the efficiency and safety of transmission line maintenance activities. This paper presents the experimental validation of the proposed method using a laboratory prototype. The prototype was tested on a 30mm diameter All-Aluminum Alloy Conductor energized through a current transformer operating at 50 Hz and 350 A. These tests were designed to evaluate the system’s ability to capture magnetic field signatures under realistic operating conditions, assess sensor performance, and verify the method’s capability to detect and localize conductor anomalies in a repeatable, safe and controlled environment.