An improved Vv traction transformer was developed to suppress heavy harmonic pollution in traction power grid.In this paper

the connection scheme of traction substation with conventional Vv traction transformer is introduced

a connection scheme of the improved Vv traction transformer is consequently proposed

and a mathematical harmonic model of the improved transformer is established.Based on the harmonic model

the implemental conditions of suppressing harmonics at the traction side are analyzed.Moreover

two simulation models of both conventional and improved Vv traction transformer systems are established according to the testing data in a traction substation

and the comparison of both simulation results shows that the improved Vv traction transformer can suppress the harmonics at its traction side effectively

and make the current waveform of grid side approach sinusoid with lower voltage degree of filter windings

which can decrease the cost of the traction system.