Optimization of supercapacitor energy storage systems and solar power systems integrated into urban railway lines to lessen CO2 emissions

The paper presents a refined approach for integrating a solar power system and supercapacitor energy storage system into the urban railway traction power supply system. The primary aim is to optimize the use of renewable energy by efficiently utilizing solar power to meet traction power demands, thereby reducing the dependence on energy from traction transformers. The proposed solution involves utilizing a combination of Newton's method with a dynamic programming algorithm. The dynamic programming algorithm de-termines the optimal energy distribution strategy among supercapacitors, solar panels, and traction transformers to minimize the objective function for each supercapacitor capacity and solar power rating. Newton's method estimates the optimal supercapacitor value to achieve the minimum objective function. The proposed method is validated through a sim-ulation model developed in MATLAB using data from the Cat Linh-Ha Dong urban railway line. The results demonstrate a 65.56% reduction in energy supplied from the grid, and further reductions are achievable in areas with higher radiation levels or expanded solar panel deployment along the railway line.