| Title |
Evaluation of Consistency for Cable Degradation Diagnosis using VLF tan δ |
| Authors |
임문섭(Mun-Seop Lim) ; 박건희(Keon-Hee Park) ; 김가현(Ga-Hyun Kim) ; 서예슬(Ye-Seul Seo) ; 임장섭(Jang-Seob Lim) |
| DOI |
https://doi.org/10.5370/KIEE.2025.74.12.2273 |
| Keywords |
VLF tan δ diagnosis; Water tree; Index R; Cable diagnosis; Statistical evaluation |
| Abstract |
Very low frequency(VLF) tan δ measurements are widely used to evaluate the insulation degradation of power cables. In Korea, diagnostic evaluations are generally performed using an Index R derived from multiple tan δ parameters. However, the conventional Index R approach has limited applicability when certain factors, such as skirt, cannot be measured. From the analysis of more than 6,000 sets of domestic underground cable data, approximately 15% of the data were found to be unsuitable for Index R calculation due to missing or unmeasurable parameters. To overcome this limitation, three diagnostic parameters(reproducibility, coefficient of determination, and sum of norm) were applied, and various parameter combinations were analyzed through a statistical approach to identify the most effective combinations for condition assessment. Based on this analysis, an alternative method for cable degradation evaluation was proposed for cases where Index R computation is not feasible.By applying the optimal combination, degradation grading became possible even for cable sections where Index R could not be calculated, demonstrating its value as a supplementary diagnostic tool. This approach can support practical decisions on cable maintenance and replacement without requiring additional testing. |