| Recently the high-speed railway is developing quickly, so it is important to research the high-speed railway's traction power supply system. Using professional simulation software PSCAD/EMTDC to simulate the steady-state and transient-state of different connection types of traction transformer, traction power supply and electric locomotive. Research is focused on the voltage-level of the bulk power system of the high-speed railway and normal-speed railway injected into at the steady-state, short-circuit capacity of the bulk power system affecting to the terminal voltage of the contact line, and the distribution of voltage and current of the contact line, the rail line and the positive feeder line when the shunt fault happened at different points in the traction power supply system. Using analytical method and digital simulation to verify the results of the voltage-level of the high-speed railway and the normal-speed railway. The results show that: (1) for the normal-speed electrificated railway system, in the case of the rating capacity of the traction transformer is 31.5 or 40MVA it is prior to consider the power system of 110KV and the power system short circuit capacity of the injection point is not less than 25 times of traction transformer's power rating capacity; when the rating capacity of the traction transformer is 50MVA, the power system short circuit capacity of the injection point is not less than 40 times of traction transformer's power rating capacity.(2)for the high-speed railway system, it is prior to consider the power system of 220KV and the power system short circuit capacity of the injection point is not less than 35 times of traction transformer's power rating capacity. The high-speed railway system can also be injected into the the power system of 110KV in some developed area where the power system short circuit capacity can match the requirement.(3) The terminal voltage of the contact line of the normal-speed railway and the high-speed railway is minimum when using the 3-phase transformer, opposited to the result of using the single-phase transformer, so the 3-phase transformer is not recommended. Because of the merits of the single-phase transformer ,we can choose the V/V transformer in some cases. For the normal-speed railway, it is suitable to choose the 3-phase transformer, but not to the high-speed railway. When the shunt fault happened on the contact line, the voltage's distribution of the contact line is affected remarkably, and less affected to the voltage's distribution of the rail line; the colser of the distance between the shunt fault point and the transformer, the worse influence to the power system,so we should avoid the shunt fault at the traction substation. |
