Protection Scheme Research Of Cophase Power Supply System

The traditional electric traction power supply system need set neutral sections, and it has problems of negative sequence, harmonics, reactive power. These problems influence the improvement of railway high-speed and overloading. On base of co-phase traction power supply system, This paper researched the co-phase continuous traction power supply system. The co-phase continuous traction power supply system can eliminate the negative sequence, improve the power factor and deal with the problem of harmonic. In addition, it can fundamentally solve the problem of neutral sections.The co-phase continuous traction power supply system which connected with the three phase power system is an AC-DC-AC system. This system constitutes by three phase rectifier, DC storage, single phase inverter and isolation transformers. In addition to solve the problem of power quality, because of many power sources supply power at the same time, this system also have advantages of long distance supply and integrated power index advanced. However, the system impedance and short circuit capacity are different from the traditional electric traction power supply system. At the same time, the fault electrical characteristics are changed. The traditional relay configurations can’t meet the new needs. So we must research on the new relay configurations which suitable for the co-phase continuous traction power supply system.First, this paper introduced the structure and characteristics of the co-phase continuous traction power supply system, analysis the development of co-phase traction power supply system and the implementation methods of co-phase traction power substation, and deduced the equivalent circuit of the AT power supply system. Then analyzed and calculated traction T-R, T-F, and F-R short-circuit parameters according the equivalent circuit. Meanwhile, this paper established the corresponding MATLAB/Simulink model simulation of AC-DC-AC traction power substation and traction nets system.At last, according to the above theory and simulation analysis, Combined with the structure and fault characteristics of the co-phase continuous traction power supply system, analyzed the action process of the protection and cooperation of different protections. From the above, Put forward a relay protection Configuration scheme which is suitable for the co-phase continuous traction power supply system.