Numerical Analysis of Electric Field for Insulation Defects in Three-Core Power Cables Based on COMSOL

Three-core power cables play a crucial role in highvoltage power transmission systems, yet they frequently suffer insulation defects that threaten reliability and safety. In this study, a two-dimensional symmetric model of a 110 kV three-core power cable was developed using COMSOL Multiphysics to simulate and analyze the electric field and potential distribution under both normal and defective conditions. The simulation specifically investigates how insulation void defects, particularly those containing moisture, affect local electric field distribution. The results demonstrate that void defects significantly distort the electric field, increasing local field intensity near defect sites by up to six times compared to normal operation conditions. Such intensified electric stress at defect sites increases the probability of partial discharge, accelerating insulation degradation and potentially leading to cable failure. These findings clarify the mechanisms by which insulation defects initiate partial discharge events, thus providing crucial insights for early fault detection and the improvement of cable monitoring and predictive maintenance strategies. The outcomes serve as a theoretical foundation for future advancements in cable diagnostics and reliability enhancement.