A self-use AC/DC-AC power supply system structure for electrified railway traction substation

Abstract

The invention discloses an AC-DC-DC power supply system structure for an electrified railway traction substation, which belongs to the application of power electronics technology in medium and low voltage power supply and distribution systems. Including step-down transformer, single-phase-three-phase converter and isolation transformer, the three-phase output of the three-phase power grid is transformed into two-phase output after passing through the three-phase-two-phase traction transformer, and connected to the two power supply arms of the traction network respectively. Each phase output of the phase output is connected to the high-voltage side of the step-down transformer, the low-voltage side of the step-down transformer is connected to the input terminal of the single-phase-three-phase converter, and the output terminal of the single-phase-three-phase converter is connected to one side of the isolation transformer. The output on the other side of the isolation transformer can supply power to the electrical equipment in the house. The system has a simple structure, partially utilizes regenerative braking energy, avoids the lack of phase of the self-use electric transformer, does not need to set up an emergency single-phase-three-phase power supply, finely compensates the harmonics of the electrified railway, improves the service life of electrical equipment, and reduces Railroad operating costs.

Description

technical field [0001] The invention relates to an AC-DC-DC power supply system structure applied to traction substations for self-use, and belongs to the application of power electronics technology in medium and low voltage power supply and distribution systems. Background technique [0002] In the traction substation, in order to ensure the normal operation and safe operation of the power supply device, it is necessary to effectively guarantee the medium and low voltage AC power consumption in the substation, including transformer cooling fan, equipment heating, battery indoor ventilation, indoor and outdoor lighting, mobile oil business, Equipment maintenance, battery charging and other equipment. In order to reliably supply power to AC self-consumption equipment, the traction substation is usually equipped with two self-consumption power transformers with a capacity of 100-200kV·A, one for working and one for standby. Each transformer should be able to independently bea...

AI Technical Summary

Problems solved by technology

At the same time, due to the problem of voltage drop at the end of the cable, an autotransformer must be added along the way to increase the voltage, which will increase the cost

[0005] 2. When taking power from the 10kV power through line, the cost needs to be calculated separately with the public grid, and the large amount of redundant electric energy in the traction power supply system and the regenerative braking energy of the locomotive cannot be used, which increases the cost of the railway transportation enterprise

[0006] 3. When directly using the self-use electric transformer to take power from the traction bus side, the wiring mode and structure of the winding vary with the wiring mode of the traction transformer, and the wiring mode and structure are more complicated

[0007] 4. When the self-use power transformer is connected to the traction side single-phase power to three-phase power, there may be a phase loss problem, so the traction substation is generally equipped with emergency single-phase-three-phase power supplies such as split cameras and phase split transformers , increasing investment in equipment and maintenance

[0008] 5. Due to the large number of AC and DC locomotives, the traction network has relatively serious power quality problems such as harmonics, and the current common shunt capacitors can only perform rough compensation

After the conversion of the self-use electric transformer, the electric energy with poor power quality is directly provided to the self-use electric equipment in the institute, which will damage the working life of the equipment.

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