Research On Scheme Of Bilateral AC Electrified Railway For Passenger Dedicated Line

In China, the unilateral power supply has been used in AC electrified railway, which depends on the power system management mode. For better economic and technical indexes, all-parallel AT traction system is widely used in passenger dedicated line. In order to meet the requirements of high-speed railway, the auto-passing phase separation system is installed in substation and section post. However, when electric locomotive is passing though the device, the over-voltage and over-current frequently happen, as well as the electric railway's reliability and the speed of electric locomotive is affected. In order to reduce the influence of the negative sequence current caused by single traction load, the passenger dedicated line is accessed to power systems by phase alternating connection, which makes the adjacent feedings of section post of the same phase. And if the bilateral power supply is implemented, the reliability and power supply capability could be improved, as well as the auto-passing phase separation system can be canceled. In this paper, the bilateral power supply technology for passenger dedicated line is analyzed and researched.On the basis of unilateral power supply system, the modification scheme of bilateral power supply's section post is presented. The current distribution, impedance, voltage drop, energy loss and the equivalent circuit of bilateral power supply are studied in theory, and the voltage drop and energy loss of bilateral power supply are compared with unilateral power supply's in theory according to passenger dedicated line parameters.The shunt current of bilateral power supply system has been deduced, and it is researched about how the shunt current affects the voltage drop, energy loss and capacity of transformer. And the problem of electricity bill measurement is discussed, which is caused by shunt current. After the unilateral power supply system is compared with bilateral power supply system, the condition is proposed, which could meet the need of bilateral power supply system.According to the scheme of bilateral power supply in passenger dedicated line, the simulation model is built based on Matlab/Simulink software platform, and which is simulated using passenger dedicated line parameters. It is indicated that the theory analysis of the current distribution, equivalent circuit and shunt current of the bilateral traction network is correct. At last, varieties of feeder short circuit fault are simulated and analyzed.