Experimental Detection of Multi-Layer Structure in High-Voltage Cable Joints Based on Ultrasound

Phased array technology can detect defects in the lead seals inside high-voltage cable joints; however, its successful application depends on the clear structure of the joint and the precise location of the lead seal. Due to the complexity of the joint structure and the inability to determine the exact position of the lead seal after installation, defect identification becomes difficult, resulting in low detection rates. To address this issue, this paper proposes a multi-layer positioning detection method based on ultrasound for high-voltage cable joints. By conducting experimental comparisons and analyses of different structural regions of the joint, the effectiveness of this method is verified. The experimental results show that a distinct echo from the insulation sealant appears at 3.5 mm, while echoes from the heat shrink tubing (waterproof tape) are observed at 34.5 mm, 22 mm, and 24 mm. Additionally, echoes from the lead seal (tail tube) are found at 36.5 mm, 24 mm, and 26 mm. The results confirm that this method can quickly and visually reflect the structural information of each layer in the joint, providing valuable reference data for the multi-layer structural positioning detection of high-voltage cable joints.