Analysis And Protection On Grounding Fault With Interruption In AT Traction System

The high-speed in passenger transport railways is a development orientation in the world. It has many excellences, such as higher-speed, stronger carrying, better safety, fewer occupied place and so on. Safety is a timeless topics in railway. Running safely and reliably is precondition of ensuring train safe in the high-speed railway AT traction system.The passenger dedicated line's traction system mostly adopts AT traction power supply. The AC-DC-AC locomotives and EMU(Electric Multiple Units) are adopted. The primary feeding protection is limitative for the new traction load. Grounding faults with interruption are detailedly analysed and studied in this paper, which plays an important part in studying feeding protection.In this paper, the impedances of various grounding faults with interruption in mongline, crewel and all-parallel AT traction system, are guided and calculated. They are compared with short faults' impedances, then their characteristics are found. The model of all-parallel AT traction system's fault is established, from which we have found the characteristic curves of impedances, current and voltage. The reason of feeding protection equipment misoperated is found.In order to studying the load characteristic, the models of AC-DC-AC locomotive and EMU are established. From them, we have gotten the current characteristic curves and the quantity of harmonic in identical power running, start-up, and regenerating brake. The current increment protection wih high-harmonic controlling is found limited for the new load.On the basis of the theory, the load currents under that three situations are compared with short faults' currents, from which the differences ofâ–³I between them are found. At last, the condition of the theory is changed, which is validated by simulation.