| Based on the characteristics of integrated main line railways,metro and light rail traction power supply systems,as well as the advantages and disadvantages of the DC system and the frequency single-phase AC system,Dr.Li Qun Zhan proposed and studied a phaseless,non-stray current system for the use of metro and light rail are the main representative of urban rail transit,and adopt the traction power supply system of industrial frequency single-phase AC system.This article mainly discusses the power supply scheme of a traction and power hybrid main substation adapted to the urban traction AC traction power supply system.This paper proposes two power frequency single-phase AC urban rail power supply main power substation schemes,which are a traction and power hybrid scheme as well as a traction and power independent scheme.The traction and electric hybrid main transformer substation scheme means that the traction power supply and the power lighting supply share the same transformer;the traction and power independent stand-alone substation schemes mean that the traction power supply and the power lighting supply are independent.The two schemes are all equipped with the same-phase power compensation device at the main substation to perform centralized compensation for the negative sequence of the entire line.This paper gives the calculation method of the compensation capacity while giving the compensation plan;urban rail transit AC traction power supply system uses AC-DC engines with a power factor of 0.98~1,it has reached the national standard and no need for reactive power compensation for locomotives.In view of the problem of using the same-phase power compensation device,the traction matching transformer,the change of the main wiring,and the increased protection of the same phase power supply compensation device,this paper discusses the relay protection schemes that are supported by the two main substation schemes.Finally,the two compensation schemes are compared from both economic and theoretical perspectives.Theoretically,both options can meet the actual needs of the project;economically,based on the actual construction and operation data of the project,comprehensive considerations are taken of various factors such as equipment,civil works,and electricity charges,and the economic operation of the two projects is analyzed.The two schemes are compared with the urban rail DC power supply system.Finally,combined with the requirements of the optimal operation of construction and economy,the conclusion that the traction-electric hybrid main transformer substation scheme is better is concluded. |
