The Impact Of Bilateral AC Electrified Railways On Power System

The rapid development of electrified railway, it not only plays a significant role in solving our tense transport capacity but also is an important influence factor for the development of the national economy. Therefore, it is very necessary to research some problems of electrified railway.In bilateral AC electrified railways, the auto-passing phase separation system of section post can be reduced. It is conducive to high-speed driving. The existing supply capacity and reliability will be further increase, relative to unilateral power supply. The bilateral AC electrified railways is better than unilateral AC electrified railways in engineering investment and operation efficiency. Meanwhile, it is also a effective method that can expand electrified railway transport capacity and strengthen the power supply reliability. Bilateral AC power supply showed the incomparable advantages because that the traction network voltage can be improved and power consumption can be decreased to ensure enough spacing between traction substation, also the investment of modification and construction can be reduced if the mode is adopted.Firstly, the impact of bilateral AC electrified railways on power system's relay protection equipment which is analysed in this paper. The conclusion indicates that the impact of bilateral AC electrified railways on power system's relay protection which could be ignored, through analysis and calculation, when power system failure occurs. The setting value of traction power system's relay protection device which is need to be reset when metallic ground short circuit fault occurs to the traction power supply system. The traction power system's relay protection device can act accurately and have no effecting on normal operation of power system's relay protection after resetting.Secondly, the problem of negative sequence current is considered in this paper. The expression of negative sequence current is deduced when the transformer is connected as V/v connection.Afterward, the actual example is calculated, the result shows that the negative sequence current in bilateral mode is larger than the one in unilateral.Finally, the bilateral AC electrified railways is simulated with MATLAB/Simulink, and the result of theoretical analysis is proved to be right. Then the power flow of reactive railway is calculated with PSASP, the consequence proves that bilateral AC supply can meet the requirement in steady-state system.