Localization and assessment of breakage defect in cables based on time–frequency domain reflectometry

Abstract

Cables are very important in urban power system due to the small occupied area and excellent electrical properties. However, the breakage defect caused by manufacturing errors and improper installation can lead to great loss to the power system. Thus, the localization and assessment of breakage defect is necessary. In this paper, a non-destructive method based on time–frequency​ domain reflectometry is utilized, and the position and degree of breakage defect can be obtained by the peaks of the localization curve. Besides, pseudo Wigner–Ville distribution is proposed to avoid the cross-term interference problem in time–frequency domain reflectometry. In experiments, breakage defects of different degrees were caused to the same position of the target cable. The defects are localized accurately with errors less than 1% of the entire cable length, and as the degree of damage increases, the peak value of the assessment curve at the defect becomes larger accordingly.