Field Study on Output Voltage Variations in DC Traction System Substations

In this paper, we analyzed the change in energy efficiency according to the output voltage of the substation before applying a device capable of active control such as electronic OLTC to the power traction system. The energy efficiency improvement for each situation was simulated by assuming two situations when the voltage was raised and when the voltage was lowered. Two railway operators compared the results of field measurement tests with the results using PSCAD/EMTDC, a power analysis program, to prove the improvement of energy efficiency according to voltage changes.