The statistical consistency review of the combination of VLF tanδ factors for the diagnosis of underground cables

Korea Electric Power Corporation (KEPCO) conducts maintenance and management for underground power distribution cables. To diagnose the deterioration of these cables, the very low frequency (VLF) tanδ method is utilized. Based on the acquired data, determination factors are derived to classify the deterioration levels and establish replacement criteria. The replacement criteria were proposed using the most effective three determination factors. However, issues such as missing diagnostic data or differences in test voltage between international and Korea have revealed situations where the derived determination factors cannot be calculated. To address these challenges, this study evaluates the validity of combinations of determination factors in terms of linearity and variability, prioritizing them accordingly. This ensures extensibility of the replacement criteria and allows for the selection of secondary combinations of determination factors.