The purpose of the study in this paper is to use the voltage stabilizing supply transformer for railway to get the power from the traction power supply system for loads along the line.On the basis of general transformer

the voltage stabilizing transformer for railway is provided with sphere gap magnetic shunt and resonant capacitor

thereby generating series-parallel ferromagnetic resonance to achieve voltage regulation.Such specific parameters as core

coil

sphere gap and capacitance of the transformer are obtained with combination of the design formula

equivalent magnetic and electric circuit of general transformer.The transformer model is established in Maxwell according to the parameters.It is shown by the simulation result that its lower limit of voltage regulation is 17 kV（the upper limit is mainly affected by the heat）

and the harmonic content is more.Therefore

the resonant filter composed of resonant capacitor and filter inductor is used for its improvement and optimization.The actually measured voltage data in the power supply section is used as the input voltage of the voltage stabilizing transformer.It is shown by the result that its harmonic suppression effect is obvious.Both theory and simulation results also show that the improved railway voltage stabilized power supply transformer has the characteristics of voltage stabilization and harmonic suppression.