Study On Protection And Control Method Of All-Parallel Traction System

China's railway construction characteristic of high-speed and heavy load is developing rapidly nowadays. Therefore traction loads increase increase severely, which makes traction electric network voltage decrease enormously. The power supply mode, which is up and down contact lines paralleled via section posts at the end of power arms, used in double track railways now cannot meet the capacity of contact lines'conductivity and electric locomotives'operating voltage. If the power supply arm length is further shortened, the number of substations will increase and device in neutral sections will become more intensive. This will not only invest more money in the traction power supply system and the construction of external power supply, but also bring more difficulties to run electric locomotives. Therefore, we must study and adopt new traction power supply-all parallel power supply.First, this paper introduced all sub-parallel power supply and analyzed its working principles. Then it made a comparison about the impedance value between separate unilateral power supply, end parallel power supply and all parallel power supply concluding the value of all sub-parallel wiring the smallest. Three options of the parallel power supply's wiring:a simple parallel wiring, semi-sub-parallel wiring and all sub-parallel wiring were proposed in order to realize all sub-parallel power supply. According to the three wring types, the impedance value of each circuit was calculated when contact network was at both normal and abnormal operation, and then came to an optimal solution.In terms of the all sub-parallel power supply, the paper analyzed the fault of each power supply section, and discussed the program of protection and the relatively protection setting calculation. Then, it discussed the controlling of combination switch and the relationship between the combined switches'logic controlling, arriving at a controlling scheme.At the end of the paper, the parallel device's installation location and access mode was settled and its structure was given. Then it discussed the process of the main control and completed the electrical schematics drawing. Key word Traction power supply system; All parallel power supply;Feeder protection; Engineering design...