Assessment of Tan \delta, Crystallinity and Dielectric Strength in XLPE Cables Through Accelerated Aging

• Main Authors: Jung, Jiho, Ahn, Ho-Rim, Choi, Gyeong-Seop, Lee, Bang-Wook
• Format: Conference Proceeding
• Language: English
• Subjects: Accelerated aging; Cables; Correlation; Degradation; Dielectric breakdown; Dielectric measurement; Dielectric Strength; Insulation; Thermal stresses; Timing; XLPE Cable; XRD Analysis
• ISSN: 2644-271X
• DOI: 10.23919/CMD62064.2024.10766237

XLPE cables are widely used in power cables due to their excellent electrical properties such as dielectric strength, dielectric loss, and insulation resistance. However, the cables undergo aging due to thermal and electrical stresses encountered during operation, leading to a decrease in insulation performance and an increased risk of failure. Therefore, accurate diagnosis of the cables is necessary to determine the appropriate timing for replacement. However, there is a lack of research on the deterioration of insulation performance and diagnosis of cables due to long-term aging. Therefore, research on the evaluation and diagnosis of insulation performance due to cable aging is necessary. In this paper, XLPE cables were artificially aged through accelerated electrical aging for 15 months, after which Tan \delta , crystallinity, and dielectric strength were evaluated. To analyze the properties according to the aging period, the Tan \delta of the cables subjected to accelerated electrical aging was measured on a monthly basis. It was observed that the Tan δ increased with the aging period. Subsequently, these cables were then fabricated into specimens for the assessment of crystallinity and dielectric strength. Crystallinity was found to increase from 0 to 13 months, after which it began to decrease. Dielectric strength was observed to decrease with the aging period. For further analysis, the correlations of Tan δ with crystallinity and with dielectric strength were separately examined. It was difficult to analyze a clear correlation between Tan \delta and crystallinity, but a decreasing correlation with dielectric strength was confirmed. The results show a general trend of how Tan δ, crystallinity and dielectric strength change as the cable ages. Tan δ and dielectric strength were found to have similar degradation characteristics. Therefore, it is anticipated that Tan \delta measurement, which is a non-destructive method, can be used to approximate the degradation of dielectric strength.