This work presents a simulation-based approach for contactless current estimation in three-phase segmented power cables using magnetic field sensing and data-driven modelling. The method aims to reconstruct symmetric phase currents from externally sampled magnetic field measurements at a realistic distance of 28.5 mm, replicating the sensor layout of a physical prototype. A high-fidelity finite element model is used as a digital twin of the real system, generating synthetic data under ideal load conditions. These data were used to assess current-estimation feasibility with lightweight, computationally efficient models. The results support the viability of non-invasive current sensing based on external magnetic field sampling and provide a baseline for future smart grid applications.