Study On The Protection Of New Traction Power Supply System In Urban Mass Transit

At present, diode rectifiers are used in China's urban rail transit traction power supply system. In this system, the power is transferred just in one direction, the DC voltage has great fluctuation, and the energy efficiency is low. The DC voltage would increase due to excess energy during the vehicle braking. The traditional solution is to set snubber resistance at the substation or vehicle. Snubber resistance can solve this problem. But this method would waste the braking energy and bring new problems, such as temperature rise. To solve above problems, a new traction power supply system is developing. It is very necessary to manufacture the protection device in the purpose of making the new traction power supply system safe and reliable.In this thesis comprehensive analysis is made between new traction power supply system and existing traction power supply system. This thesis studies the current protection system principles, methods, and movements with the tuning relations. Then to manufacture the DC protection device. Firstly, the short-circuit characteristics of the existing traction power supply system are simulated, the DC protection method is analyzed. Secondly, the topology of the new traction power supply system is studied. The simulation model of the new traction power supply system is established and the short-circuit characteristics are simulated. Comparative analysis is made between the two systems. On the basis of the difference between the two systems, the protection for new traction power supply system is established, including the protection of new traction power supply installations, the protection of DC Incoming Cabinet, the protection of DC Feeder Cabinet, the protection of Negative Cabinet. The configuration of the principle, the setting of the protection methods and the movements with the relationship are given. Finally, Starting from the device's overall the design of software and hardware of the protection device is made. The simulation experiment of the device is made.Initial results show that the method is feasible and the device Satisfies the requirements of the system. The device has been applied in National Key Technologies R&D Program for the 11th Five-year Plan,'study of key technologies and equipment of new linear motor transportation system'...