Simulation-Based Ampacity Assessment of Cable Joints Based on Hotspot-Temperature Inversion

Latent insulation defects complicate the ampacity assessment of high-voltage cable intermediate joints because localized electrical stress may increase without a discernible change in surface temperature. This study develops a simulation-based framework that combines electro-thermal analysis, Gaussian-kernel inversion, and current-limit calculation to investigate the potential incorporation of simulated defect information into allowable-current assessment. A 25-dimensional feature representation supports the estimation of internal hotspot temperature and the numerical discrimination between healthy and defective insulation states. The simulations reveal that micro-scale defects substantially intensify localized electric fields but produce only negligible surface-temperature variations, highlighting the difficulty of assessing internal insulation conditions from thermal measurements alone. Under noise-free simulation conditions, the model demonstrates the numerical separability of healthy and defective insulation states within the simulated dataset. A bisection solver determines the allowable current subject to the hotspot-temperature limit, while an illustrative heuristic derating rule adjusts this current to account for potential risks associated with insulation defects. The framework provides a simulation-based approach for investigating the integration of hotspot-temperature estimation and defect-related current adjustment, while highlighting the need for improved noise robustness and experimental validation before practical application.