The harmonic analysis of traction power system based on a new Vv traction transformer

Traction power system of electrical railway has nonlinear loads, which produces a great quantity of harmonics which will affect power quality of grid unavoidably. For Traditional Vv transformer does not have filtering capacity, all the harmonics are delivered to the grid. In this paper, a new Vv transformer that has filtering capacity is raised. What is more, its equivalent circuit and harmonic model are proposed, and its filtering theory is analyzed. At the end, the simulation model of the traditional Vv and the new Vv wiring transformers in the traction power system are established and the harmonic character is analyzed. The simulation results show that, the new Vv transformer can suppress the harmonics at its traction side effectively, lower harmonic content of grid side, and lower harmful influence of harmonic to traction transformer.