Ultrasonic Guided Wave Imaging and fusion Using A0/S0 Modes for Corrosion Detection in Ground Wires

Overhead ground wires are critical for ensuring the safety and reliability of high-voltage transmission systems, yet they are highly susceptible to corrosion due to harsh environmental exposure. Traditional inspection methods often struggle with early-stage defect detection and scalability. In this study, a baseline-free multimodal ultrasonic guided wave (UGW) imaging framework is proposed for corrosion detection in overhead ground wires. The method leverages mode-selective excitation of A0 and So Lamb wave modes, frequency-domain synthetic aperture focusing (SAFT), and multimodal image-level fusion to enhance damage localization accuracy and robustness. Experimental validation on representative specimens demonstrates that the proposed technique achieves high-resolution defect imaging, with a minimum resolvable axial defect spacing of 13 mm and significant improvements in defect detection sensitivity and spatial resolution. This work offers a scalable, intelligent solution for insitu monitoring and proactive maintenance of power transmission infrastructure.