Direct-mounted modular three-phase-to-single-phase power supply system for rail transit

Abstract

The invention discloses a direct-mounted modular three-phase-to-single-phase power supply system for rail transit. The system comprises a pre-stage module, a high-frequency transformer and a post-stage module. The pre-stage module comprises three groups of units, the input ends of the pre-stage module perform connection according to a Y type or a [delta] type and is directly mounted on a three-phase middle-high voltage power grid through an electric reactor; the output of the pre-stage module is connected with the input of the post-stage module through a high-frequency transformer; the post-stage module comprises three groups of units, the outputs of the post-stage module are connected in series to form single-phase high-voltage output. The direct-mounted modular three-phase-to-single-phase power supply system for rail transit is in three-phase current balance without a negative sequence component, and a reactive current and a harmonic current in a network are completely controlled; the modular configuration is convenient to maintain; the whole power density is high to avoid a power frequency transformer with a large volume; and the fault tolerance is high, and a certain number ofmodules having faults cannot influence system output.

Description

technical field [0001] The invention belongs to the field of same-phase power supply for rail transit, in particular to a direct-mounted modular three-phase-to-single-phase power supply system for rail transit. Background technique [0002] The traction load of the electrified railway is a single-phase AC load, which makes the three-phase of the traction power supply system seriously unbalanced and has reactive current. In order to reduce the impact of three-phase unbalance, the traction transformer is connected by commutation, resulting in different voltages in each power supply section, which must be separated by phase-splitting insulators. The phase-splitting insulator restricts the smooth and continuous current receiving of the locomotive, and becomes a weak link of power supply, restricting the development of high-speed and heavy-haul railways. [0003] At present, some substations use the same-phase power supply technology, which is connected to the power grid through...

AI Technical Summary

Problems solved by technology

Phase-splitting insulators limit the smooth and continuous flow of locomotives, and become a weak link in power supply, restricting the development of high-speed and heavy-duty railways

[0003] At present, some substations use the same-phase power supply technology, which is connected to the power grid through the Scott transformer, and the comprehensive compensation current of the system is detected in real time, and the active filter is controlled to balance the three phases and filter out the reactive current. The primary side of the traction transformer is no longer Rotation, substations of the same-phase power supply system do not need to install phase-splitting insulators, but the use of Scott power frequency transformers occupies a large area and costs high

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