Urban rail power supply system double-coil connected medium-voltage energy-feeding system and its energy-feeding method

Abstract

The invention discloses a double-coil connected medium-voltage power feed system and a power feed method for an urban rail power supply system. The system includes a rectifier transformer, a double-coil connected power feed device and a rectifier unit. The type energy feed device comprises two double energy feed branches arranged in parallel, and each heavy energy feed branch includes an AC-side low-voltage circuit breaker, an isolation transformer, an inverter and a DC-side contactor arranged in series; the method steps include: When starting, the rectifier transformer and rectifier unit take current from the medium-voltage AC power grid and inject it into the DC traction network; Feed back the train braking energy to the medium voltage AC grid. The invention can realize energy saving and DC bus voltage stabilization, and has the advantages of high flexibility, small size, high degree of integration with existing systems, high power factor, low harmonics injected into the AC side, and good versatility.

Description

technical field [0001] The invention relates to an urban rail power supply system, in particular to a double-coil connected medium-voltage energy feed system and an energy feed method for the urban rail power supply system. Background technique [0002] At present, in the urban rail traction power supply system, there are mainly two solutions for dealing with the regenerative energy generated when the train brakes. One is the low-voltage feedback + resistance consumption solution, which feeds the braking energy back to the low-voltage power distribution AC400V grid. The excess energy is consumed by the braking resistor. Because the capacity of the low-voltage distribution transformer is small, when the braking energy is large, most of the energy is consumed by the braking resistor, and the recycling rate of the regenerative energy is low; the other is The medium-voltage energy feedback scheme (independent branch type) is to feed back the braking energy to the medium-voltage ...

AI Technical Summary

Problems solved by technology

This technical solution adopts adding one or more parallel DC / DC converter modules at the DC traction bus, so that the electric energy generated when the locomotive brakes can be partially fed back to the grid through the AC / DC module, and partly passed through the DC / DC module. After the voltage is boosted, it is stored in an independent capacitor bank to overcome the impact of all energy instantaneously fed back to the grid. The impact on the grid is reduced by adding hardware, which increases equipment cost and floor space, and the logic of feedback and energy absorption is complicated. It is difficult to realize and will affect the reliability of equipment work

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