Modeling and Analysis of DC Traction Power Supply System Based on Bidirectional Converter Device

Reversible substations with bidirectional converter devices are capable of feeding regenerative braking energy back to middle voltage distribution network, while supporting power to DC traction power supply system. And the output voltage of bidirectional converter device can be controlled. In this paper, the output characteristics of bidirectional converter and its power supply calculation model are studied. The AC/DC integrated power flow calculating algorithm is derived. To verify the algorithm, a case is studied. A specific moment in simulation is analyzed to verify the converge performance and reliability of algorithm. Voltage regulation, no-load voltage and capacity of bidirectional inverter device are main factors influencing its output characteristic. The influence of these factors on power peak, rail potential and traction network voltage is studied. When the no-load voltage is between 1500V and 1650V, to keep traction network voltage and rail potential in limits, the optimal slope of output characteristic should be 5.5% to 6%, and optimal voltage regulation should be 0.157 to 0.179. The maximum peak active power of traction substations with bidirectional converters need to achieve 7.3MW to 7.4MW.