Research On Reliability Of Three Phase AC Traction Power Supply System For Urban Rail Transit

Urban rail transit is an important means of transportation.With the vigorous development of the city and the increasing demand of daily life,the speed of train is constantly improving.At the same time,the complexity of the traction power supply system that provides power for electric locomotives is getting higher,and the requirements are becoming strict.Therefore,it becomes more and more important on the safe and reliable operation of the traction power supply system.Through the research on the reliability of the traction power supply system,it is beneficial to deeply understand and grasp the whole system from the perspective of reliability,so as to effectively update and use the equipment in technology,evaluate and repair the equipment in a planned way in management,and strive to improve the reliability and economic benefits of the system.The three-phase AC traction power supply system of urban rail transit introduced in this paper adopts a technical program with comprehensive advantages,two-stage three-phase power supply from medium voltage to low voltage,and "two lines and one place" contact structure.Compared with the traditional DC power supply program for urban rail transit,the three-phase AC traction power supply system program can eradicate stray current corrosion.In a certain range,there is no electrical phase separation,which has better economy and higher reliability.In order to evaluate the reliability of the system qualitatively and quantitatively,this paper divides the three-phase AC power supply system of urban rail transit into four subsystems,and evaluates the reliability of the core parts of each subsystem,which are the main substation,three-phase cable,traction substation and contact zone.Firstly,several commonly used reliability analysis methods and reliability analysis indicators are briefly introduced in this paper.By analyzing the structure and technical characteristics of the three-phase AC traction power supply system of urban rail transit,and comparing it with traditional DC traction power supply system,it is concluded that GO method is the suitable reliability analysis method for the system.Then,the paper focused on the introduce of GO analysis method and establishing the reliability model of the main substation by using the GO method,and using the calculation results to analyze the key elements which affects the reliability of the main substation the most.Then,for the three-phase cable,the effective calculation model under different lengths of cable is established with the distribution scheme of substation along a practical line as the research object,and the reliability parameters are calculated from the two backup schemes of no backup and 100% backup respectively.Finally,some measures to improve reliability are proposed.Finally,according to the structural characteristics of the contact zone and the structure and parameters of the contact rail,the reliability of the catenary along the line is calculated in the unit of anchor joint.Integrated the reliability calculation results of each subsystem and analyzed the weak links of the system,compared the reliability parameters of the three-phase AC system with that of the single-phase AC power supply system,and proposed the reliability improvement measures for each part of the system.