Determination of Allowable Current in MVDC Distribution Cables Considering Environmental Variations

This study investigates the allowable current and the transient thermal response of MVDC power cables, specifically ACSR and XLPE types, using the Finite Element Method. To reflect real operating conditions, annual environmental temperature data from Suwon, Korea, were applied as dynamic boundary conditions. Steady-state analysis was first conducted to determine the ampacity, with the conductor temperature limited to 90 ℃. A monthly fault scenario was then simulated to evaluate the cooling and reheating rates, which characterize the thermal response of each cable type. The results show that ampacity strongly depends on cable structure and material properties. Overhead ACSR cables exhibit faster cooling and reheating than underground XLPE cables, due to their distinct heat dissipation mechanisms. These findings highlight the importance of a dynamic rating approach that accounts for environmental variations, rather than relying solely on static values. Furthermore, the quantified thermal response rates provide essential data for developing overload protection and operational strategies. This study therefore offers fundamental insights for the reliable and efficient design of future MVDC distribution networks.