Rail transit power supply system twin coil access medium-voltage energy feed system and method

Abstract

The invention discloses a rail transit power supply system twin coil access medium-voltage energy feed system and method. The system comprises a rectification transformer, a twin coil access energy feed device, and a rectification unit. The twin coil access energy feed device comprises two energy feed branches arranged in parallel. Each energy feed branch comprises an AC-side low-voltage breaker, an isolation transformer, an inverter, and a DC-side contactor which are successively arranged in series. The method comprises steps that current is acquired from a medium-voltage AC power grid and is supplied to a DC traction network by means of the rectification transformer and the rectification unit when a train is started; and the twin coil access energy feed device is started and train braking energy is fed back to the medium-voltage AC power grid via the twin coil access energy feed device and the rectification transformer when the train is braked. The system may achieve energy conservation and stable DC bus voltage, is good in flexibility, small in size, high in combination with a conventional system, high in power factor, low in harmonic injected into an AC side, and good in universality.

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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