Electrified railway traction power supply and energy storage device and method thereof

Abstract

The invention discloses an electrified railway traction power supply and energy storage device and a method of the electrified railway traction power supply and energy storage device. The energy storage device is connected between a feeding arm alpha or feeding arm beta at the output end of a traction transformer and a steel rail, or two energy storage devices are connected between the feeding arm alpha and the steel rail and between the feeding arm beta and the steel rail respectively, wherein the energy storage device is arranged in a traction substation. The energy storage device comprises a control unit, an isolation transformer, a PWM current transformer, an energy transformation circuit and an energy storage element, wherein the PWM current transformer, the energy transformation circuit and the energy storage element are connected in sequence, and the control unit is used for carrying out calculation according to the voltage, current and direction of the feeding arm alpha and / or feeding arm beta to complete control over the PWM current transformer and the energy transformation circuit and achieve energy exchange between the energy storage device and the feeding section connected with the energy storage device. The electrified railway traction power supply and energy storage device can fully recycle locomotive braking feedback electric energy, improve the energy utilization ratio of a traction power supply system, reduce the installation billing capacity of the traction transformer, reduce cost and absorb and store energy even in electricity valleys, has the effect of peak load shifting and further has the functions of dynamic reactive-power compensation and low-order harmonic suppression.

Description

technical field [0001] The invention relates to the field of electrified railways, in particular to a traction power supply energy storage device and a method thereof applied in the field of electrified railways. Background technique [0002] At present, the world's energy is becoming increasingly tense, and energy conservation and consumption reduction have become a worldwide research topic, and energy recovery and reuse is an effective means of energy conservation and consumption reduction. In recent years, with the development of my country's rail transit field, especially the high-speed and heavy-duty electrified railways, railways, as a key energy-consuming industry, have great potential in energy recovery and reuse. On the one hand, the electrified railway traction power supply system does not have a high utilization rate of electric locomotive braking feedback power, and in many cases it is directly fed back to the three-phase AC grid, which cannot produce economic be...

AI Technical Summary

Problems solved by technology

When the energy is fed back to the three-phase grid, it will cause problems such as voltage increase, negative sequence current increase, and line loss increase, and because the power department will not bill the returned electric energy, it will not produce economic benefits for the traction power supply system

[0004] Secondly, since the power consumed by the traction load changes periodically, in order to maintain the balance of power supply and demand at any time, the capacity of the traction transformer is generally designed according to the maximum power consumed by the load, and in most cases the traction transformer will not be fully loaded running, which results in a waste of capacity

The waste of traction transformer capacity leads to an increase in cost, which is mainly reflected in two aspects. One is the increase in the initial installation cost of the traction transformer, and the other is the increase in the basic electricity fee due to the current two-part electricity price in my country.

[0005] At the same time, the traction load will cause power quality problems such as reactive power, harmonics, and negative sequence

Generally, traction substations will install compensation devices such as fixed capacitors to improve power factor for reactive power problems, but generally no suppression measures are taken for harmonic problems

[0008] (1) The existing electrified railway traction power supply system generally does not have a high utilization rate of electric locomotive braking feedback power, and the economic benefits are low, and it will also cause some power quality problems;

[0009] (2) The capacity of the traction transformer is generally determined according to the peak power consumed by the traction load. In most cases, the existing system cannot operate at full load, resulting in a waste of traction transformer capacity and increasing system costs;

[0010] (3) At present, in the DC traction power supply network of urban rail transit, no technical solution has been found to reduce the capacity of the traction transformer by releasing energy;

[0011] (4) The existing technologies generally use separate devices to recycle electric energy or deal with power quality problems such as reactive power and harmonics, with single functions and high costs

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