The effects of no-load voltage level of traction power supplies on energy consumption of a mass rail transit system

The energy consumption per train*km depends on many factors including characteristics of vehicles, line geometry, and power supply system. Regenerative braking system usage is one of the most effective methods of reducing energy consumption, and is a common practice in mass rail transit systems. Regenerated energy and receptivity rate of it depends on various parameters. One of these parameters is the no-load (output) voltage value of the rectifier substations. Common practice is to apply around 10% higher value compared to nominal voltage value. However, the values available in existing systems differ from each other. In this study, simulation software is used for simulating different no-load voltage values for a couple of 750 VDC and 1500 VDC fed systems with real line and vehicle data. Results of these simulations are analyzed for energy consumption related values as well as train performance.