Research On Cophased Traction Power System’s Scheme And Control Strategy

Since the beginning of the21st century, the railway has flourished in the world, especially the very rapid development of China’s railway. High-speed, heavy haul railway development has greatly changed people’s concept of space-time, and have an important impact on human resources flow, information flow and cultural awareness. Research on railway technology has great significance in promoting the economic, cultural development and human progress.The electrified railway traction power supply system is facing major issues, including power quality problems, passing the neutral section, economical operation issues. In order to fully solve the above problem, a large amount of equipment needs to be equiped in traction power supply system. However that would not only need the large investment, but also bring a challenge to the system reliability as a reslt of the complexity of the system. Cophased tracion power supply system attracted widespread attention was presented and discussed to solve the above problem in this paper.Based on kinds of traction transformer type, passive symmetrical compensation and active symmetrical compensation was discussed to construct the cophased power supply system, futherly, a new scheme of cophased traction powe system based on hybrid compensation was presented and analysed.The overall structure of the cophased power supply system based on the new auto-transformer power supply system was also proposed. Non-phase-locked loop single-phase current detection methods and control method stategy for cophased tracion power system based on active symmetrical compensation and hybrid symmetrical compensation technology were analyzed. At last, the result of simulation verified system architecture, the control strategy and current detecion.Cophased traction power system’s compensation capacity was deduced considering all kinds of windings-connected type transformer and kinds of compensaton scheme. Take the cophased tracion power system construced by Vv transformer and power flow controler as. an example, the compensation capacity design method based on the satisfaction optimization of power quality was discussed, what’s more, power flow controler’s capacity real-time optimal distribution control strategy was laso analysed. A numerical example based on measured data, shows that the satisfaction optimization compensation approach can significantly reduce the compensation capacity, improve system economy.Finally, the operating result of the actual cophased traction power system with high conversion efficiency show that the system can cancell the neutral section, improve power quality of reactive and negative sequence significantly, improve the utilization of traction transformers. This cophased traction power system is also contributed to reduce system loss to improve the regenerative braking energy utilization.