Energy Evaluation for DC Railway Systems with Inverting Substations

Energy and environmental sustainability in transportation have received a great deal of attention in recent decades. Electrified railway systems play an important role in contributing to the reduction of energy usage and CO2 emissions compared with other transport modes. For metro-transit systems with frequently motoring and braking trains, the effective use of regenerated braking energy is a significant way to reduce the net energy consumption. This paper presents a simulation method to evaluate the energy flow of DC railway systems. The network receptivity of railway systems with and without inverting substations are analyzed and compared. The power load in inverting substations is illustrated based on a case study. The results show that the inherent receptivity of a non-inverting system varies with the operation timetable. A shorter headway operation timetable could lead to a higher receptivity, but the headway is not the only factor. With the implementation of inverting substations, the receptivity can be improved. In addition, the global energy can be reduced by 10-40% with different timetables.