Sensitivity Analysis‐Based Transmission System Expansion Planning with Multiple Options for Relieving Congestion

The integration of renewable energy sources (RESs), such as photovoltaic generation systems or wind farms, has resulted in congestion issues in transmission lines. For further RES integration, transmission systems must be expanded to prevent congestion. Recently, congestion management via the introduction of dynamic line rating (DLR) and battery energy storage systems has gained attention as a possible solution. However, these new technologies are limited by uncertainties in RES output and weather conditions. This paper proposes a transmission‐expansion planning method that can successively consider combinations of expansion options in a short amount of time. The effectiveness of the proposed method is numerically demonstrated through case studies for the IEEE 14‐bus system and the IEEJ EAST‐10 model. The simulation results show that the proposed method can significantly reduce calculation time while maintaining accuracy. The reduction in computational load enables the development of complex transmission‐expansion planning, including the installation of DLR and battery energy storage system (BESS), under evaluations based on a wide variety of scenarios that assume uncertainties in demand, RES output, weather conditions, and other factors. © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.