The Structure Design of a New Railway Stabilized Voltage Supply Transformer Based on the Power Quality Optimization of Traction Network

As the key equipment in electrified railway, power transformer is mainly responsible for obtaining electricity from traction network. The output voltage can supply a large number of different types of non-traction loads along the line. However, in the face of frequent voltage fluctuation and rich harmonic content of the traction network, it is commonly difficult to obtain electricity for traditional power transformers. Moreover, the unbalanced secondary load and large negative-sequence current of the traditional power transformer pose a serious threat to the power quality of electrified railways. Therefore, aimed at the voltage characteristics of traction network, this paper analyzes the equivalent magnetic circuit and equivalent circuit of power transformer. Based on the optimization of the power quality of the traction network, resonant capacitors and filtering inductors are utilized to form a resonant filter. As a result, in this study, based on magnetic shunt with air gap and resonant circuit, a new structure design of anti-harmonic stabilized voltage transformer is proposed. The Maxwell simulation results show that the new structure design can stabilize voltage and suppress harmonic. Meanwhile, the power quality of traction network can be optimized effectively, which proves that the proposed method is feasible.