Negative sequence control system for AT power supply mode of electrified railway traction power supply system

Abstract

The invention relates to a negative sequence control system for an AT power supply mode of an electrified railway traction power supply system, solves the negative sequence problem of the AT power supply mode economically and effectively, optimizes the traction network structure, and achieves the through-type power supply of a traction substation. The system comprises the traction substation for supplying power to a left power supply arm and a right power supply arm, the traction substation is provided with a balanced traction transformer and an alternate current / direct current converter, a high voltage incoming power is converted into a two-phase electricity with a voltage rating of 27.5kV and a phase angle difference of 90 degrees by the balanced traction transformer, one phase is used as a T-phase power supply contact network of the AT power supply mode, the other phase passes through the alternate current / direct current converter, and a voltage having an angle difference of 180 degrees with the phase angle of the T phase is output as an F-phase power supply positive feed line of the AT power supply mode; the neutral point of the balanced traction transformer is connected to a generalized ground line.

Description

technical field [0001] The invention relates to an electrified railway traction power supply system, in particular to a negative sequence control system applied to the power supply mode of an autotransformer (hereinafter referred to as AT) of the electrified railway traction power supply system. Background technique [0002] Due to the advantages of high efficiency, low energy consumption, and no pollution, electric traction has been widely used in railways around the world. my country's electrified railways adopt a single-phase power frequency (50Hz) AC 25kV power supply system. The single-phase power supply method used in the traction network leads to unbalanced three-phase loads in the power supply system, resulting in a negative sequence impact on the power system; the use of AC flexible power supply technology for electric locomotives leads to distortion of current and voltage waveforms in the power supply system, resulting in harmonic impact on the power system ; Tradi...

AI Technical Summary

Problems solved by technology

However, for the solution to the negative sequence problem using non-single-phase traction transformers, there are also large fluctuations in the traction load, and the power supply loads of different phases on the low-voltage side of the traction transformer often vary greatly. Reduced or even ineffective problems

In addition, considering that one phase load is traction or regeneration, and the other phase load is regeneration or traction, that is, when the two-phase load conditions are just opposite, the negative sequences generated by the two-phase loads will not only be unable to offset, but will be superimposed and magnified

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