Three-phase combined same-phase power supply and transformation structure

Abstract

The invention discloses a three-phase combined same-phase power supply and transformation structure which comprises a traction transformer and same-phase power supply devices. The traction transformer and the same-phase power supply devices are of single-phase structures, and each same-phase power supply device comprises a high-voltage matching transformer, an alternating-current, direct-current and alternating-current converter and a traction matching transformer; primary-side windings of the two high-voltage matching transformers and a primary-side winding of the traction transformer form a delta connection assembly. Secondary-side windings of the high-voltage matching transformers are connected with input ends of the alternating-current, direct-current and alternating-current converters, and output ends of the alternating-current, direct-current and alternating-current converters are connected with primary sides of the traction matching transformers. The amplitude and the phase of a voltage of a secondary-side winding of the traction transformer are identical to the amplitudes and the phases of voltages of secondary-side windings of the traction matching transformers, and the secondary-side winding of the traction transformer and the secondary-side windings of the traction matching transformers are connected with a traction bus. The three-phase combined same-phase power supply and transformation structure has the advantages that traction power supply resources can be optimally configured, construction investment can be reduced, and an energy conservation effect is obvious; the three-phase combined same-phase power supply and transformation structure not only brings convenience for same-phase power supply modification for Vv wiring or Vx wiring traction substations, but also is applicable to replacing traction transformers by a group of novel same-phase power supply devices to implement comprehensive same-phase power supply in the future.

Description

technical field [0001] The invention relates to the field of AC electrified railway power supply, in particular to a three-phase combined in-phase power supply and transformation structure. Background technique [0002] Electrified railways generally adopt the single-phase power frequency AC system powered by the public power system. In order to make the single-phase traction load be distributed as balanced as possible in the three-phase power system, the electrified railway often adopts the scheme of rotating phase sequence and separate phase and partition power supply. The adjacent power supply areas at the phase-splitting partitions are divided by phase-splitting insulators to form electrical split phases, also known as phase splits. In order to prevent electric locomotives from burning out catenary suspension components caused by arcing due to over-separation of phases, and even causing phase-to-phase short-circuit and other accidents, as the train speed continues to inc...

AI Technical Summary

Problems solved by technology

[0003] High-speed and heavy-duty railways have widely used high-power AC-DC electric locomotives or EMUs based on full-control devices such as IGBTs and IGCTs. The core is traction converters with multiple sets of four-quadrant PWM control and multiple control. The content is small, and the power factor is close to 1, but the traction power of AC-DC electric locomotives or EMUs is large. For example, the rated power of single-vehicle high-speed EMUs running in large formations can reach 25MW (equivalent to 5 trains of ordinary speed railways). The power quality problems caused by high-power single-phase loads on the three-phase grid, mainly caused by three-phase voltage unbalance (negative sequence), are becoming more and more serious, and must be paid attention to.

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