A novel configuration and control strategy for railway powering distance extension

Contemporary electrified railway power systems (RPSs) use a sectionalized power supply with sections spanning 30∼50 km. This conventional design, however, suffers from key shortcomings: energy waste and grid instability caused by regenerative braking energy (RBE) feedback, low transformer utilization increasing costs, and capacity constraints from neutral zones. In response to these challenges, this study introduces a powering range-extended RPS (PRE-RPS). It reorganizes three sequential traction substations (TSSs) into a unified management cell. The central TSS (e.g., TSS #2) is replaced by a powering distance extension converter (PDEC), and neutral sections are removed to form an uninterrupted segment. This eliminates the main transformer and its upstream grid, reducing capital costs. A major advantage is the doubling of the power supply range for a terminal TSS (e.g., TSS #1 or #3), which promotes local RBE absorption and reduces train speed losses. The TSS-PDEC-TSS cooperative cell addresses sectionalized-operation drawbacks like low transformer utilization, high peak demand charges, and voltage sag, which in turn improves system energy efficiency and cuts operational expenses. A robust, coordinated control strategy is developed to manage load uncertainties. Simulations based on a real RPS confirm secure operation with notable performance gains: energy charges are reduced by 25%, demand charges by 14%, and RBE recovery improved by over 50%. The system also shows significant potential for increasing railway transport capacity.