A power quality conditioner for electrified railway

Abstract

The present invention is a kind of electrified railway power quality conditioner, comprises single-phase multi-winding transformer, single-phase single-winding transformer, converter (I, II) and electric capacity; One end of the converter I is connected in series, the other end of the converter I is connected in parallel with the capacitor and then connected back to back with the converter II, and the converters II are connected in a chain structure and then connected in series with the single-phase single-winding primary winding. The present invention adopts a single-phase transformer and a chain structure, which can reduce switching loss, improve device operation efficiency and reliability, reduce the number of device links, reduce the complexity of device structure, improve control accuracy, and reduce the pulse output to the control system Synchronization requirements. The invention solves the problems of negative sequence, reactive power and harmonic exceeding standard in the traction station of the electric railway, and has the advantages of small occupied area of ​​the device, small loss, simple control, low cost and high reliability.

Description

Technical field: [0001] The invention relates to the fields of electrified railway power supply, power electronics technology and power quality control, in particular to an electrified railway power quality regulator. Background technique: [0002] The load of electrified railway has the characteristics of nonlinearity, asymmetry and fluctuation. On the one hand, since the electrified railway traction power supply system adopts single-phase power supply mode, and the electric locomotive is a single-phase load, no matter what wiring mode the traction transformer adopts, a large negative sequence current will be injected into the system; on the other hand, due to the The locomotive uses power electronic converters, so a large number of harmonics are injected into the system. In addition, because the load of the traction substation fluctuates at any time with the number of trains in the power supply arm and the operating status of each train, the load of electrified railways a...

AI Technical Summary

Problems solved by technology

But the disadvantage of this method is: TCR itself also generates harmonics, and the compensation for negative sequence is limited

Since the rated voltage of the traction bus in the traction station is 27.5kV, and the AT power supply mode is 55kV, limited by the withstand voltage level of the current fully-controlled power devices, the chain-type structure converter directly connected to the traction network through the reactor will lead to If the 3300V grade IGBT devices that are currently more mature are used, the number of modules cascaded will reach 30 at the 27.5kV voltage level, and the number will more than double under the AT power supply mode, resulting in control problems. At the same time, it will also lead to too many windings of the large-capacity single-phase multi-winding transformer on the other side of the back-to-back, resulting in complex process, difficult design, and large footprint of the transformer, which is difficult in practical application.

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