A Modified Thyristor-Based Auto-Passing Neutral Section Scheme With One Auxiliary Transformer

Abstract

The existence of the neutral section is used to be a major problem of the AC electrified railway. Although the conventional thyristor-based auto-passing neutral section schemes allow a train to go through the neutral section with power, there still exists a power interruption time in milliseconds and the issue of the inrush current in the on-board transformer. Aimed at these shortcomings, a modified thyristor-based scheme with one simplified auxiliary transformer is proposed in this paper. By introducing one 3:1 transformer and two additional switches, two transition voltages, whose phases are between that of two power supply arms, are constructed. The neutral section voltage is switched three times when a train passes through so as to avoid the significant voltage phase change on the grid side of the electric locomotive. Meanwhile, the power interruption time can be lowered to hundreds of microseconds and the inrush current of the on-board transformer is effectively avoided. The working principle of the proposed scheme is deeply analyzed and the characteristics are discussed. Further, the effectiveness and superiority of the proposed scheme is verified by the simulation and experimental results. The impact of the neutral section on the train can be well suppressed by the proposed scheme.

Keywords

• Auxiliary transformer
• flux linkage
• neutral section
• power interruption time
• switch-based scheme