Research On The Two-Phase SVG In Improving Power Quality Of Electric Railway

Railway is one of the important conveyances. There are two kinds of traction device such as electric-engine and gas-engine in our country nowadays. Along with the National Economy and each aspects of the social high-speed developing ceaselessly, the railway transport has become the shortage source. The electrization of railway can improve the ability of transportation and reform the railway works, and be in favor of carrying out the distribution with reason of transit,reducing the cost of business,protecting the environments also. Therefore the electrization represents unexampled superiority in railway transition comparing to the others. Our country had constructed 43 Electric railways at the end of 2005, the total length reached 20132 kilometers. That made china become the third country which Electric railway's length exceeded 20 thousands kilometers after the Russia,Germany. The high-speed developing of it brought severe Power Quality's problem, going with expanding the carrying capability and facilitated the economy. That produced bad influence to Power network,the other consumers and itself.The two-phase SVG about electric railway power quality fathering synthetically .That researched in this paper aimed at the running manner of some traction substation in our country. The substation imports two 110kV sources from a 220kV transformer substation, whose short-cut capability is 450MVA. It supplies to the electric engine through the Impedance-Matched Balance Transformer. The SVG designed to the electric characteristic of the substation in this study. It is capable of reducing availably the impact on the Power System from the transaction supply system and ensured the voltage level of electric engine.It was discussed that the concepts of Power Quality and the actuality about electric railway Power Quality in this paper, several FACTS devices were described, which based on the electric electron technology. The principle of the traction supply system and the load trait were expounded. The present detected means of the harmonics and reactive current were introduced. On the base of analyzing the principle of SVG, two-phase SVG was recommended to improving the power quality of electric railway. That fitted to the high-speed electric railway traction supply system which based on Impedance-Matched Balance Transformer. The compensation mechanism and arithmetic was studied grounded on analyzing the electric parameter. Compared with traditional three-phase SVG used in power system, active power can be exchanged between two single phase inverter through the common dc capacitor, so that the system imbalance can be extremely improved. The software simulation was achieved through PSCAD/EMTDC to the detected data actually of a transformer substation in Shanxi province, and the power quality parameter was checked generally to the result of the simulation. Based on the analysis and simulation, the conclusion that the two-phase SVG is perfect equipment for improving the power quality of electric railway was carried out.