A Pulsed Electromagnetic Eddy Current Method for Detecting Broken Strands of ACSR Conductor in Steel/AL Materials

Differ from common cables, aluminum conductor steel reinforced (ACSR) conductors are characterized by internal tensile body of the steel strand and external twisted aluminum strand. Their quality is vital for the safe operation of power grid. However, current researches have been few dedicated studies on broken strands in ACSR conductors. In this paper, a pulsed electromagnetic eddy current (PEMEC) method is proposed to detect the defects of broken strands, in which they occur in steel/AL strands. First, the detection principle is analyzed based on the electromagnetic field propagation properties. Second, this paper describes the damage features from three dimensions: balanced signal, differential signal, and AC magnetic flux density. Basing on the theoretical approach and damage features, this study suggests a PEMEC detection steps to accurately distinguish the broken strand at different positions. Meanwhile, a finite element model is built in COMSOL software, and the PEMEC method’ validity is proved, when it is used to detect the varying types, widths and fracture depths of damage in ACSR conductors. In addition, this paper performs a first-order fitting of simulation results to achieve quantification of the damages. Finally, our work is expected to achieve comprehensive detection for broken strands of ACSR conductors.