| As the traction transformer requires frequent switching operations, once subjected to prolonged high amplitude, high frequency over-voltage attack, it will not only reduce the performance of the transformer, affect the locomotive operation, but also change the power system parameters on the system to produce instability. Therefore, to make full research on the generated mechanism of traction transformer load switching over-voltage and the generated mechanism of inrush current, and to analyze the damage on the system, and then find the appropriate measures to curb the over-voltage has great economic significance.In this dissertation, two UMEC models of single-phase multi-winding transformer and three-phase limb transformer are deduced from the single-phase double-wound transformer firstly, and an UMEC model of Scott transformer was constructed and the operational matrix of voltage and current of Scott transformer winding under steady and transient state are obtained, according to the UMEC model of single-phase multi-winding transformer. Then the structure of traction network is introduced, and the modules needed in simulation are constructed on the basis of practical situation, and engineering calculation and analysis are processed based on the actual parameter of these models.Secondly, on the basis of the analysis of research on tractive power supply system simulation, PSCAD/EMTDC is applied to construct the simulation models and obtain their simulation waveform on transient state of no-load switch and fault recovery of traction transformer with various kinds of windings, while the asynchronism of the beaker switch on and the impacts of primary side over-voltage and Inrush are not considered in the researches on no-load switch on of traction transformer. Then the waveforms are analyzed, and with the comparison of simulation results, the correction of the simulation models of tractive power supply system is testified. The models can meet the need of electrical analysis in tractive power supply system.at the same time,asessment the over-voltage and inrush current and identify the corresponding measures to inhibit the over-voltage. |
