Modeling And Simulation Of Energy-Saving Wound-Core Traction Transformer For Electrified Railway

With the rapid development of the electrified railway, the number of traction transformers becomes bigger and the capacity becomes larger. Meanwhile, the traction load rate of electrified railway in our country is so low that the no-load loss problem of traction transformers is not allowed to be ignored. Therefore, energy-saving research of traction transformers is significant. Compared with other transformer energy-saving technologies, the wound core technology has certain advantages in aspects such as economy and feasibility. Therefore, the wound core technology is adopted as key in energy-saving traction transformer research. It may have some deficiency when using conventional analysis methods in simulation because of its core particularity, but finite element method(FEM) has advantages in the simulation analysis of transformers with such a special structure. However, past FEM researchs of wound core transformer were focused on rural or factory distribution transformers, etc., in terms of traction transformer, this kind of research is relatively deficiency. An finite element model of the energy-saving wound core traction transformer has been built in Ansoft Maxwell, and the modeling method has been verified in this paper. Using the finite element model, the following works have been completed:No-load test and short-circuit test of the energy-saving wound core traction transformer have been simulated. Combined with the actual winding connection mode, excitation circuit model for the3D transient finite element model of the energy-saving traction transformer has been designed and built. The energy-saving wound core traction transformer has been simulated by using the finite element model. The simulation results show that no-load current of the energy-saving wound core traction transformer reduces by about50%and no-load loss reduces by24%, percentage of short circuit voltage also falls compared to fold core traction transformer with the same capacity. The simulation results are consistent with the theory.Core temperature field simulation has been done. An electromagnetic-thermal coupling simulation model of the energy-saving wound core traction transformer has been built in ANSYS Workbench simulation platform. According to the load curve, the core temperature distribution on different load conditions has been simulated. The simulation results show that the wound core meet demands of the traction transformer overload operation. Compared with the fold core transformer with the same capacity, core temperature distribution of the energy-saving wound core traction transformer is more uniform, and the average temperature is lower. The simulation results of temperature field simulation are consistent with the theoretical analysis that the flux distribution of wound core is more uniform, and the correctness of the model has been verified.