Flexible hub traction substation architecture for electrified railway

Abstract

An electrified railway flexible hub traction substation framework is characterized in that an alpha power supply arm and a beta power supply arm are connected to a three-phase power grid through a traction transformer, and two alternating current ends of a back-to-back converter are respectively connected to the alpha power supply arm and the beta power supply arm; the power distribution system bus is connected to a railway power distribution network through a first grid-connected transformer, and the power distribution system load is connected to the power distribution system bus through a power distribution transformer; the system further comprises an energy feedback system. The energy feedback system comprises a bidirectional DC / AC converter and a second grid-connected transformer. The direct current end of the bidirectional DC / AC converter is connected to the direct current end of the back-to-back converter, and the alternating current end of the bidirectional DC / AC converter is connected to the power distribution system bus through the second grid-connected transformer. The beneficial effects of the utility model lie in that the traction power supply system and the railway power distribution network are connected through the energy feedback system, mutual transfer of active power flow of the traction power supply system and the railway power distribution network can be realized, and the operation energy efficiency of railway power supply is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of traction power supply system, and particularly to a flexible hub traction substation architecture of electrified railway. BACKGROUND

[0002] With the rapid development of electrified railway, the construction of low-carbon, energy-saving, and grid-friendly railway power supply system will be conducive to the environment-friendly transportation and power energy system has become a global consensus. The flexible traction substation integrated with power electronic converter, energy storage system and renewable energy is considered as an effective solution to achieve this goal. It provides renewable power to reduce carbon emissions, provides energy buffer to recover regenerative braking energy, and provides flexible potential for tidal flow scheduling to improve energy efficiency and power quality. Thanks to the above advantages, the flexible traction substation can provide comprehensive and excellent solutions for sustainable and efficient operation of railway power supply system. However, the existing flexible traction substation architecture only accesses energy storage, photovoltaic and the like for conventional traction substation, and does not consider the architecture of accessing energy storage, photovoltaic, electric vehicle charging and hydrogen energy system in the coexistence scenario of traction power supply system and railway distribution system in the hub traction substation. CONTENT OF THE UTILITY MODEL

[0003] The utility model aims at providing a flexible hub traction substation architecture of electrified railway.

[0004] The technical scheme for realizing the utility model aims at the following:

[0005] A flexible hub traction substation architecture of electrified railway, the alpha power supply arm and the beta power supply arm are connected to a three-phase power grid through a traction transformer, and the two alternating current ends of the back-to-back converter are connected to the alpha power supply arm and the beta power supply arm respectively; the distribution system bus is connected to the railway distribution network through a first grid-connected transformer, and the distribution system load is connected to the distribution system bus through a distribution transformer; further comprising an energy feedback system; the energy feedback system comprises a bidirectional DC / AC converter and a second grid-connected transformer; the direct current end of the bidirectional DC / AC converter is connected to the direct current end of the back-to-back converter, and the alternating current end of the bidirectional DC / AC converter is connected to the distribution system bus through the second grid-connected transformer.

[0006] Further, further comprising an energy storage system; the energy storage system comprises a bidirectional DC / DC converter and an energy storage medium; the energy storage medium is connected to the direct current end of the back-to-back converter through the bidirectional DC / DC converter.

[0007] Further, the power supply system further comprises a photovoltaic system; the photovoltaic system comprises an isolation transformer, an AC / DC converter and a photovoltaic unit; the power supply system bus is connected to the photovoltaic unit through the isolation transformer and the AC / DC converter in sequence. Alternatively, the power supply system further comprises a charging system; the charging system comprises an isolation transformer and an AC / DC converter; the power supply system bus is connected to the AC / DC converter through the isolation transformer; and a direct current end of the AC / DC converter is used for connecting an electric vehicle. Alternatively, the power supply system further comprises a hydrogen energy system; the hydrogen energy system comprises an isolation transformer, an AC / DC converter and a hydrogen energy load; and the power supply system bus is connected to the hydrogen energy load through the isolation transformer and the AC / DC converter in sequence.

[0008] Preferably, the α power supply arm and the β power supply arm are connected to the direct power supply line and / or the AT power supply line.

[0009] Preferably, the α power supply arm and the β power supply arm are connected to the three-phase power grid through the traction transformer, and specifically, the V / V connection, the V / X connection, the SCOTT connection or the balanced connection mode is adopted.

[0010] The traction power supply system and the railway power distribution network can be connected through the energy feedback system, active power flow of the traction power supply system and the railway power distribution network can be transferred to each other, and operation energy efficiency of railway power supply is improved. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 A schematic diagram of the traction substation architecture of the electrified railway flexible hub.

[0012] Figure 2 A schematic diagram of the direct power supply and the AT power supply in parallel in the traction substation architecture of the electrified railway flexible hub.

[0013] Figure 3 A schematic diagram of the energy storage system connected in the traction substation architecture of the electrified railway flexible hub.

[0014] Figure 4 A schematic diagram of the photovoltaic system connected in the traction substation architecture of the electrified railway flexible hub.

[0015] Figure 5 A schematic diagram of the charging system connected in the traction substation architecture of the electrified railway flexible hub.

[0016] Figure 6 A schematic diagram of the hydrogen energy system connected in the traction substation architecture of the electrified railway flexible hub. DETAILED DESCRIPTION

[0017] The utility model is further explained in connection with the drawings and specific embodiments.

[0018] AsFigure 1 As shown, the architecture of a flexible hub traction substation for electrified railways includes a traction power supply system, back-to-back converters, a power feeder system, and a 10kV railway power distribution system. The traction power supply system includes traction transformers and power supply lines; the primary side of the traction transformer is connected to phases A, B, and C of the three-phase power grid, and the secondary side is connected to the traction busbars of the α-phase power supply arm, the β-phase power supply arm, and the ground. The contact wires of the direct-supply power supply lines are connected to the traction busbars of the α-phase power supply arm and the β-phase power supply arm, respectively. The rails of the direct-supply power supply lines are connected to the ground. The back-to-back converters include isolation transformers T1 and T2, and four-quadrant converters C1 and C2. The input of T1 is connected to the α-phase power supply arm, and its output is connected to the AC side of C1. The input of T2 is connected to the β-phase power supply arm, and its output is connected to the AC side of C2. The power feeder system includes a bidirectional DC / AC converter C4 and a grid-connected transformer T3. The DC terminal of C4 is connected to the DC side of C1 and C2, and its AC terminal is connected to one end of T3. The other end of T3 is connected to the distribution system busbar. The 10kV distribution system includes distribution transformer T4 and distribution load D1. The three terminals of the primary side of T4 are connected to phases A, B, and C of the railway distribution network, respectively, and the three terminals of the secondary side are connected to the distribution system busbar. Distribution load D1 includes isolation transformer T5 and railway distribution system load S2.

[0019] The power supply lines for the traction power supply system can also adopt AT power supply mode, or a combination of direct power supply and AT power supply mode, such as... Figure 2 As shown.

[0020] In the above architecture, the three-phase power grid is connected to the α power supply arm and β power supply arm through traction transformers, and can adopt V / V connection, V / X connection, SCOTT connection, balanced connection and other forms.

[0021] To recover and utilize regenerative braking energy from the traction power supply system, flexible hub traction substations can be connected to energy storage systems, such as... Figure 3 As shown. The energy storage system includes a bidirectional DC / DC converter C4 and an energy storage medium S2. One end of C4 is connected to the DC side of C1 and C2, and the other end is connected to the energy storage medium S2.

[0022] The railway 10kV power distribution system can be connected to photovoltaic system D2, such as Figure 4 As shown, the photovoltaic system D2 includes an isolation transformer T6, an AC / DC converter C5, and photovoltaic units. The power distribution system busbar is connected to the photovoltaic units sequentially through the isolation transformer T6 and the AC / DC converter C5. After connecting to the photovoltaic system D2, in conjunction with the energy storage system, the regenerative braking energy of the traction power supply system and the surplus photovoltaic power generation energy of the railway power distribution system can be recovered and utilized, thereby improving the energy efficiency of the traction power supply system and the railway power distribution network.

[0023] The railway's 10kV power distribution system can also be connected to the charging system D3. Charging system D3 includes an isolation transformer T7 and an AC / DC converter C6; the power distribution system busbar is connected to the AC / DC converter C6 via the isolation transformer T7; the DC terminal of the AC / DC converter is used to connect to the electric vehicles. By connecting the railway's 10kV power distribution system to charging system D3, the regenerative braking energy from the traction power supply system can be used to charge the electric vehicles.

[0024] The railway 10kV power distribution system can also be simultaneously connected to photovoltaic system D2 and charging system D3, such as Figure 5 As shown. In this way, the regenerative braking energy of the traction power supply system and the photovoltaic power generation of the D2 system can be used to charge the electric vehicle.

[0025] The railway's 10kV power distribution system can also be connected to the hydrogen energy system D4. The hydrogen energy system D4 includes an isolation transformer T8, an AC / DC converter C7, and hydrogen energy loads. The power distribution system busbars are connected to the hydrogen energy loads sequentially through the isolation transformer T8 and the AC / DC converter C7. The hydrogen energy loads include hydrogen fuel cells and hydrogen electrolysis production units, which are also connected to hydrogen storage devices. After the railway's 10kV power distribution system is connected to the hydrogen energy system D4, it can utilize the regenerative braking energy from the traction power supply system to achieve clean energy hydrogen production. Simultaneously, the stored hydrogen energy can be used to supply power to the traction power supply system and the railway power distribution network, as well as to hydrogen loads such as hydrogen-powered vehicles.

[0026] The railway 10kV power distribution system can also be simultaneously connected to photovoltaic system D2 and hydrogen energy system D4, such as Figure 6 As shown. In this way, clean energy hydrogen production can be achieved by utilizing the regenerative braking energy of the traction power supply system and the D2 power generation of the photovoltaic system.

Claims

1. A flexible hub traction substation architecture for electrified railway, wherein an α power supply arm and a β power supply arm are connected to a three-phase power grid via a traction transformer, and two AC terminals of a back-to-back converter are connected to the α power supply arm and the β power supply arm respectively; the power distribution system busbar is connected to the railway power distribution network via a first grid-connected transformer, and the power distribution system load is connected to the power distribution system busbar via a power distribution transformer; Its features are, It also includes a power supply system; the power supply system includes a bidirectional DC / AC converter and a second grid-connected transformer; the DC terminal of the bidirectional DC / AC converter is connected to the DC terminal of the back-to-back converter, and the AC terminal of the bidirectional DC / AC converter is connected to the power distribution system bus through the second grid-connected transformer.

2. The electrified railway flexible hub traction substation architecture as described in claim 1, characterized in that, It also includes an energy storage system; the energy storage system includes a bidirectional DC / DC converter and an energy storage medium; the energy storage medium is connected to the DC terminal of the back-to-back converter through the bidirectional DC / DC converter.

3. The electrified railway flexible hub traction substation architecture as described in claim 2, characterized in that, It also includes a photovoltaic system; the photovoltaic system includes an isolation transformer, an AC / DC converter and photovoltaic units; the power distribution system bus is connected to the photovoltaic units in sequence through the isolation transformer and the AC / DC converter.

4. The electrified railway flexible hub traction substation architecture as described in claim 2, characterized in that, It also includes a charging system; the charging system includes an isolation transformer and an AC / DC converter; the power distribution system bus is connected to the AC / DC converter through the isolation transformer; the DC terminal of the AC / DC converter is used to connect to the electric vehicle.

5. The electrified railway flexible hub traction substation architecture as described in claim 2, characterized in that, It also includes a hydrogen energy system; the hydrogen energy system includes an isolation transformer, an AC / DC converter, and a hydrogen energy load; the power distribution system bus is connected to the hydrogen energy load in sequence through the isolation transformer and the AC / DC converter.

6. The electrified railway flexible hub traction substation architecture as described in claim 1, characterized in that, The α power supply arm and β power supply arm are connected to the direct power supply line and / or the AT power supply line.

7. The electrified railway flexible hub traction substation architecture as described in claim 1, characterized in that, The α power supply arm and β power supply arm are connected to the three-phase power grid through a traction transformer, specifically by using V / V connection, V / X connection, SCOTT connection or balanced connection.

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