Moisture Degradation Characteristics and Multi- Performance-Based Status Assessment Method of Distribution Cables

Understanding the degradation characteristics and assessing the operating status are crucial for improving the service quality of distribution cables. Moisture ingress in cables is a common defect leading to cable failures and associated economic losses. However, conducting targeted detection and prevention is challenging due to the lack of knowledge on the development process and assessment methods. In this study, cables with various common defects were operated in a water immersion environment for a 90-cycle accelerated moisture degradation test. The influence of moisture was highlighted in addition to other setting factors, including electric fields, high temperatures, and typical defects. Additionally, the electrical performances of the test cables were periodically tested, and a combined weighting approach based on the subject-oriented analytic hierarchy process (AHP) and object-oriented entropy weight method (EWM) was proposed. Furthermore, a comprehensive depiction of degradation status was provided through an assessment method utilizing the improved radar chart and two parameters, degradation index DI and degradation rate DR, derived from curve area calculation. Consequently, the findings revealed varying degradation characteristics in cables subjected to moisture ingress via different pathways. The moisture ingress through the cable joint and damaged body had the most significant impact on insulation, exceeding that of other defects. The proposed methods and parameters could effectively assess the moisture ingress and degradation status of distribution cables, which can offer critical guidance for the detection and prevention of cable dampness issues.