Defect Detection of Cable Termination Based on the Microwave Reflection Method

To reduce the hidden defects of cable terminations, a microwave reflection method is proposed to detect the internal defects of cable terminations. This method allows for fast, nondestructive, and accurate identification of tiny defects in cable joints at the millimeter level. In this article, a theoretical model of the microwave reflection process in the multilayer medium containing defects was established first. According to the model, the reflection coefficients at the place with or without defects were calculated, respectively, which theoretically confirms the feasibility of the microwave detection method. Then, we used CST software to build a simulation model to investigate the effects of defect size, defect type, silicone rubber thickness, and detection distance. To verify the results of the theoretical calculations, we conducted a series of microwave test experiments, and a method for identifying the internal defects of cable terminations was proposed. Finally, a 2-mm2 minor defect was successfully identified with the proposed method. This microwave-based nondestructive testing method is economical and does not cause radiation damage to the operator, which can help us quickly to discover potential defects in cable terminations and have extensive application prospects.