A Novel Hybrid Energy Storage Configuration Framework for Mountain Electrified Railways with Long and Steep Slopes

The electrified railways in high-altitude mountainous areas often feature long and steep slopes. These characteristics pose two primary challenges: traction network overvoltage caused by regenerative braking energy (RBE) in downhill and train stalls in uphill sections due to insufficient voltage supply. Configuring energy storage is feasible for recycling RBE and ensuring a stable power supply. However, existing research merely focuses on the size of energy storage systems, failing to address the optimal siting and sizing problem adequately. To this end, this paper proposes a novel hybrid energy storage system (HESS) configuration framework. Firstly, the operation status of the train on long and steep slopes is analyzed, and RBE is decomposed into components suitable for the battery and supercapacitor based on a variational mode decomposition. Secondly, regarding the traction station, section post, and overhead contact line as HESS’s candidate locations, the types of trains are considered, and a siting and sizing optimization model is built to pursue the cost-benefit and traction network voltage. Finally, an improved combining multiobjective optimization with differential evolution (ICMODE) algorithm is proposed to solve the model. The simulation results validate the effectiveness of the method based on the actual data.