Research On The Continuous Co-phase Transformation Scheme For Heavy-haul Railway Traction Power Supply System

Due to the characteristics of the traction load for the power frequency single-phase AC electrified railway,many problems that exist in the heavy-haul traction will become more prominent.At present,the heavy-haul railway industry in China is developing vigorously,and the transportation capacity is strengthened with the traction number is increasing,but its power supply system does not yet have the power supply capacity suitable for the annual traffic.Therefore,making for use of existing resources and existing key technologies is of great importance for further research on traction power supply system of heavy-haul railways.There are two main power supply mode of direct supply and AT supply in China’s existing railway lines.Although the AT power supply mode has the advantages of small impedance traction electric network and power-supply long distance,but also have many defects such as more traction substation facilities,large civil engineering and so on.Therefore,this paper mainly researches the long distance power supply technology on direct supply mode,the number of traction substations and neutral section in the section post can be reduced,as well as the external power supply interfaces,at the same time,power supply distance can be extended greatly.In order to better adapt to heavy-haul railway and improve the line transport capacity also operational benefit,the combined co-phase power supply technology can be used to eliminate neutral section at the outlet of traction substation,so as to achieve continuous co-phase power supply without phase separation in all lines and improve power quality.The equivalent model of single-track overhead line+direct supply,as well as the calculating deduction of impedance of traction electric network and traction network voltage loss when paralleled at the end or bilateral connected at the section post of double-track mode in this paper are deduced.At the same time,the theoretical calculation of catenary’s current carrying capacity for double-track direct suppling and the design of combined co-phase power supply system capacity are further analyzed.MATLAB/Simulink is used in this paper to build the simulation model of the double-track direct power supply system that set up overhead line,and to prove the correctness of equivalent circuit model derived from the theory,as well as to simulate the overhead line+direct supply system compared with the TRNF power supply system to analysis research.At the same time,a systematic simulation analysis for continuous co-phase reconstruction scheme of traction power supply system proposed by taking a heavy-loaded railway line as an example have done in this paper.It is verified that the equalizing current is not generated when the section post bilateral connected to supply power,and the superiority of the scheme in terms of power supply capacity and lifting transport capacity.Finally,in order to show that the optimized scheme of heavy-haul railway continuous co-phase power supply system has better economy efficiency,a comparative analysis about the cost investment and benefit return from original traction power supply system scheme and reformed design scheme has been done by reconfiguring capacity of single-three-phase combined co-phase power supply system in optimizing distributed traction substation.