Research on Damage Identification of Overhead Ground Wires in Cable Clips Based on ASTFA and Time-Frequency Entropy

The transmission of electric energy relies on the power steel strand, and the suspension clamp on the electrical tower is the key component of the power steel strand. The structure of the suspension clamp has a semi-closed feature, which makes the steel strands in the clamp more likely to have more hidden defects after being exposed to external effects such as wind load, rain erosion or lightning strikes. In order to effectively detect the status of overhead cables in the clamp section, a damage identification method based on ASTFA and the time-frequency entropy of the signal is proposed according to the common defect characteristics and guided wave characteristics of the cable. First, analyze the propagation characteristics of the guided wave in the steel strand; secondly, introduce the self-adaptive sparsest time-frequency analysis algorithm and time-frequency entropy to construct the damage assessment index, and calculate the finite element simulation signal to initially verify the index Effectiveness; Finally, laboratory and field experiments have proved the feasibility of this method. The results show that: (1) Low-frequency longitudinal guided waves are more suitable for steel strand detection. In this paper, the L(0,1) mode of 64kHz is selected. (2) As the degree of damage increases, the value of the damage assessment index increases, and the frequency of guided waves has a limited influence on the index value. (3) According to the experiment, the damage degree evaluation range is divided, the field test proves that the index is more reliable.