Railway standby power system based on AC-DC-AC purification and energy storage power supply

Abstract

The utility model relates to the technical field of electrified railways, and discloses a railway standby power system based on AC-DC-AC purification and an energy storage power supply, which comprises an AC-DC-AC power supply device and an energy storage power supply device. A railway 27.5 kV contact network power supply is processed by the AC-DC-AC power supply device and is output to the energy storage power supply device; the AC-DC-AC power supply device comprises an AC-DC-AC purification power supply and an isolation transformer; the energy storage power supply device comprises an anti-reverse power transmission device, a static change-over switch module, an energy storage converter module, an energy storage module and an energy storage management system; the static change-over switch module realizes automatic switching of grid connection and grid disconnection between a 10kV through line power supply and a 27.5 kV contact network power supply; the energy storage converter module is connected with a converter which is arranged between the energy storage module and a power grid and is used for realizing electric energy bidirectional conversion; by adding an AC-DC-AC power supply device and an energy storage power supply device, a third standby power supply is added for a railway, and the problem that power supply is unreliable due to the fact that a power supply system does not have an independent second power supply or has a false second power supply is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of electrified railways, and in particular to a railway backup power system based on AC / DC / AC purification and energy storage power supply. Background Art

[0002] At present, the normal operation of railway signal equipment is directly related to driving safety, and its power load level is level 1. According to relevant regulations, level 1 loads should be supplied by dual power supplies to power equipment or low-voltage dual power switching devices.

[0003] For some railways or railway lines where it is difficult to connect to external power supplies, the railway power supply system has only one through power supply line to provide a relatively reliable power supply. The other power supply is connected to the local 10KV power grid or connected by the overhead contact network.

[0004] The reliability of the second power supply connected by T is poor. For this situation, the current "Railway Electric Traction Power Supply Design Specification" and "Railway Electric Power Design Specification" both stipulate that power can be obtained from the secondary side of the traction transformer by installing a power transformer. The power supply obtained from the traction network through the 27.5kV power transformer was measured, and the effective value of the voltage varied from 154V to 286V; the peak voltage varied from 210V to 450V; and the harmonic distortion rate TOHD of the voltage harmonic content exceeded 20%. This voltage can easily cause abnormal operation or damage of the power load, and the power quality cannot be guaranteed.

[0005] In actual operation, when the through power supply is shut down for maintenance, the second power supply connected by T is used as the main power supply for signal equipment, and the local power grid trips and the contact network is shut down, causing the second power supply to be interrupted. Some distribution stations with existing railway through and self-closing lines may have power from the same bureau. When the power supply is shut down for maintenance, the two through and self-closing lines will lose power, resulting in unreliable power supply.

[0006] To achieve green transformation of railway transportation energy and improve the self-consistent power supply capacity of primary signal loads in railway stations, a railway backup power system based on AC / DC purification and energy storage power supply is needed. Utility Model Content

[0007] The utility model aims to solve the problem of poor reliability of the existing second power supply by proposing a railway backup power system based on AC / DC purification and energy storage power supply in view of the deficiencies of the existing technology.

[0008] In order to achieve the above technical objectives, the technical solution adopted by the utility model is:

[0009] A railway backup power supply system based on AC-DC-AC purification and energy storage power supply, including an AC-DC-AC power supply device and an energy storage power supply device; the 27.5kV catenary power supply of the railway first passes through the AC-DC-AC power supply device and is output to the energy storage power supply device;

[0010] The AC-DC-AC power supply device includes an AC-DC-AC purification power supply and an isolation transformer; the AC-DC-AC power supply device adopts a topological structure of a rectifier circuit + an inverter circuit; the 27.5kV catenary power supply of the railway is connected to the AC-DC-AC purification power supply and the isolation transformer in sequence through a single-phase transformer;

[0011] The energy storage power supply device includes an anti-backfeeding power supply device, a static transfer switch module, an energy storage converter module, an energy storage module, and an energy storage management system;

[0012] The 27.5kV catenary power supply of the railway is connected to the anti-backfeeding power supply device, the energy storage converter module, and the energy storage module in sequence through the AC-DC-AC power supply device 1;

[0013] The 27.5kV catenary and the 10kV through line power supply are connected in parallel through the static transfer switch module, and the static transfer switch module realizes the automatic switching and off-grid of the 10kV through line power supply and the 27.5kV catenary power supply;

[0014] The energy storage converter module is a converter that realizes bidirectional power conversion between the energy storage module and the power grid or load; the energy storage converter module realizes the energy exchange between the energy storage module and the power grid through the battery management system, and controls and manages the charge and discharge of the energy storage module;

[0015] The energy storage management system is responsible for monitoring battery data and protecting battery safety; it realizes the internal energy control of the system through data acquisition, network monitoring, and energy scheduling to ensure the normal operation of the entire system.

[0016] As a further optimization of the solution, the input of the AC-DC-AC power supply device is connected to the 0.23kV side of the 27.5kV step-up transformer. After being transformed by the AC-DC-AC power supply device, it realizes single-phase split-phase three-phase output, and realizes the output of a stable 0.4kV AC power supply that meets the requirements of communication and signals.

[0017] As a further optimization of the solution, the rectifier circuit of the AC-DC-AC power supply device consists of a single-phase bridge rectifier and a filter circuit. The AC power input is processed by the single-phase bridge rectifier and the corresponding filter circuit, and is transformed into a DC voltage with an amplitude of about 150V, initially suppressing the large fluctuations and harmonic effects of the catenary voltage;

[0018] The inverter circuit of the AC-DC-AC power supply device consists of three parts: inversion, filtering, and voltage transformation. The inversion part adopts a single-phase full-bridge structure. The inverter circuit consists of three single-phase fully controlled bridge inverters with exactly the same structure and isolated from each other and an output transformer, forming a three-phase circuit.

[0019] As a further optimization of the solution, the energy storage power supply device further includes a low-voltage dual power supply switching device.

[0020] As a further optimization of the solution, the operation modes of the energy storage power supply device are grid-connected charging mode and off-grid discharging mode. The grid-connected charging mode means that the power supply loop accessed by the energy storage power supply device is powered normally, and at this time, the energy storage converter module is in the grid-connected charging mode; the off-grid discharging mode means that the power supply loop accessed by the energy storage power supply device is powered abnormally, and at this time, the energy storage converter module is in the off-grid discharging mode to provide voltage and frequency support for the electrical equipment.

[0021] The beneficial effects of adopting the above technical solutions are as follows:

[0022] By adding an AC-DC-AC power supply device and an energy storage power supply device to the original conventional power supply system, a third standby power supply is added nearby for the first-level signal loads of railway stations, solving the problem of unreliable power supply caused by the lack of an independent "second power supply" or the existence of a "false second power supply" in the existing power supply system, improving the stability and reliability of the signal power supply for train operation, and ensuring the transportation safety of trains. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of a railway standby power supply system based on AC-DC-AC purification and energy storage power supply;

[0024] Figure 2 It is a topology diagram of the AC-DC-AC power supply device;

[0025] Figure 3 It is a topology diagram of the energy storage power supply device;

[0026] Figure 4 It is a schematic diagram of the energy storage power supply device;

[0027] Reference Numerals: 1. AC-DC-AC power supply device, 2. Energy storage power supply device, 11. AC-DC-AC purification power supply, 12. Isolation transformer, 21. Anti-backfeeding power device, 22. Static switch module, 23. Energy storage converter module, 24. Energy storage module, 25. Energy storage management system, 26. Uninterruptible power supply, 27. Monitoring, 28. Distribution switch, 31. 27.5 kV catenary power supply, 32. Single-phase transformer, 41. 10 kV through line power supply. Detailed Embodiments

[0028] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts belong to the scope of protection of the present utility model.

[0029] A railway standby power supply system based on an AC-DC-AC purification and energy storage power supply includes an AC-DC-AC power supply device 1 and an energy storage power supply device 2; the 27.5 kV catenary power supply 31 of the railway first passes through the AC-DC-AC power supply device 1 and is output to the energy storage power supply device 2; the AC-DC-AC power supply device 1 includes an AC-DC-AC purification power supply 11 and an isolation transformer 12; the AC-DC-AC power supply device 1 adopts a topological structure of a rectification circuit + an inversion circuit; the 27.5 kV catenary power supply 31 of the railway is sequentially connected to the AC-DC-AC purification power supply 11 and the isolation transformer 12 through a single-phase transformer 32; the energy storage power supply device 2 includes an anti-backfeeding power device 21, a static switch module 22, an energy storage converter module 23, an energy storage module 24, and an energy storage management system; the 27.5 kV catenary power supply 31 of the railway is sequentially connected to the anti-backfeeding power device 21, the energy storage converter module 23, and the energy storage module 24 through the AC-DC-AC power supply device 1; the 27.5 kV catenary and the 10 kV through line power supply are connected in parallel through the static switch module 22, and the static switch module 22 realizes the automatic switching and off-grid of the 10 kV through line power supply 41 and the 27.5 kV catenary power supply 31; the energy storage converter module 23 is a converter that realizes bidirectional power conversion between the energy storage module 24 and the power grid or load; the energy storage converter module 23 realizes the energy exchange between the energy storage module 24 and the power grid through the battery management system, and controls and manages the charging and discharging of the energy storage module 24; the energy storage management system is responsible for monitoring battery data and protecting battery safety; through data acquisition, network monitoring, and energy scheduling, the internal energy control of the system is realized to ensure the normal operation of the entire system.

[0030] Embodiment 1

[0031] The input of the AC-DC-AC power supply device 1 is connected to the 0.23 kV side of the 27.5 kV step-up transformer. After being transformed by the AC-DC-AC power supply device 1, single-phase split-phase three-phase output is achieved, realizing the output of a stable 0.4 kV AC power supply required for communication and signals. The rectifier circuit of the AC-DC-AC power supply device 1 consists of a single-phase bridge rectifier and a filter circuit. The AC power input is processed by the single-phase bridge rectifier and the corresponding filter circuit, and is transformed into a DC voltage with an amplitude of about 150 V, initially suppressing the large fluctuations in the catenary voltage and the influence of harmonics. The inverter circuit of the AC-DC-AC power supply device 1 consists of three parts: inversion, filtering, and voltage transformation. The inversion part adopts a single-phase full-bridge structure. The inverter circuit consists of three single-phase fully controlled bridge inverters with exactly the same structure and isolated from each other and an output transformer, forming a three-phase circuit. The energy storage power supply device 2 also includes a low-voltage dual-power switching device. The operating modes of the energy storage power supply device 2 are grid-connected charging mode and off-grid discharging mode. The grid-connected charging mode means that the power supply circuit connected to the energy storage power supply device 2 is powered normally. At this time, the energy storage converter module 23 is in the grid-connected charging mode. The off-grid discharging mode means that the power supply circuit connected to the energy storage power supply device 2 is powered abnormally. At this time, the energy storage converter module 23 is in the off-grid discharging mode, providing voltage and frequency support for electrical equipment.

[0032] Embodiment 2

[0033] The utility model patent proposes a self-consistent power supply system using an AC-DC-AC purification and energy storage power supply, which includes: an AC-DC-AC purification power supply, a static transfer switch module, an energy storage converter module, a lithium battery management system, an energy management system, an intelligent fire protection system, an intelligent temperature control system, etc.

[0034] Considering that the current railway station obtains power from the secondary side of the traction transformer, the effective value and peak value of the voltage vary within a large range, and the voltage harmonic content Uthd exceeds 20%. Such voltage is likely to cause abnormal operation or damage to electrical loads. To solve this problem, it is proposed to use an AC-DC-AC type purification power supply to first perform harmonic purification treatment and split-phase output alternating current with high power quality to meet the signal power supply requirements.

[0035] To ensure the uninterrupted use of railway electrical loads and meet the standard requirements of providing dual power sources for first-class loads, it is proposed to use an energy storage emergency power supply system, which mainly consists of a battery module, an energy storage converter, a battery management system, and an energy management system. Among them, the battery module is responsible for storing electricity; the energy storage converter is a converter that realizes bidirectional power conversion between the battery system and the power grid (or load); the battery management system and the energy management system are the management and control centers of the energy storage system. The battery management system is mainly responsible for monitoring battery data and protecting battery safety; the energy management system mainly realizes internal energy control of the system through data acquisition, network monitoring, and energy scheduling to ensure the normal operation of the entire system.

[0036] By using the self-consistent power backup system of AC-DC-AC + energy storage proposed in this utility model patent, the following can be achieved:

[0037] 1) Analyze the current situation of railway power supply in certain areas and configure a corresponding energy storage emergency power supply + self-consistent power supply and backup system of AC-DC-AC type purification power supply;

[0038] 2) Achieve harmonic purification treatment and split-phase output through the AC-DC-AC type purification power supply;

[0039] 3) Achieve the switching between grid-connected and off-grid power backup through the energy storage emergency power supply;

[0040] Embodiment III

[0041] This utility model patent proposes a self-consistent power backup system using AC-DC-AC purification and energy storage emergency power supply. The system includes an AC-DC-AC power supply device 1 (AC-DC-AC type purification power supply) and an energy storage power supply device 2 (energy storage cabinet part). The AC-DC-AC part includes an AC-DC-AC purification power supply and an isolation transformer; the energy storage cabinet part includes an anti-backfeeding device, a static transfer switch module, an energy storage inverter module, a lithium battery management system, etc.

[0042] 1. AC-DC-AC type purification power supply

[0043] The 27.5kV catenary power supply first undergoes AC-DC-AC power processing and outputs a stable power supply with less than 2% harmonics to the intelligent energy storage emergency power supply system and the low-voltage dual-power switching device.

[0044] The AC-DC-AC purification power supply mainly adopts a topological structure of a rectifier circuit + an inverter circuit (including an isolation transformer). The input of the AC-DC-AC is connected to the 0.23kV side of the 27.5kV step-up transformer. After transformation by the AC-DC-AC device, it realizes single-phase split-phase three-phase output and outputs a stable 0.4kV AC power supply required for communication and signals.

[0045] 1) Rectifier circuit

[0046] It consists of a single-phase bridge rectifier and a filter circuit. The AC power input is processed by the single-phase bridge rectifier and the corresponding filter circuit and is transformed into a DC voltage with an amplitude of about 150V, initially suppressing the large fluctuations and harmonic effects of the catenary voltage.

[0047] 2) Inverter circuit

[0048] The main circuit of the inverter consists of three parts: inversion, filtering, and voltage transformation. The inversion part adopts a single-phase full-bridge structure, which converts the input direct current into alternating current with sinusoidal pulse width modulation. The fundamental frequency of this alternating current is the required power output frequency. The pulse width modulation wave output by the inverter is filtered by LC to become a smooth sinusoidal wave, and then transformed by a transformer to obtain sinusoidal alternating current with the required voltage level. The inversion circuit consists of three single-phase fully controlled bridge inverters with exactly the same structure and isolated from each other, and an output transformer, forming a three-phase circuit.

[0049] To achieve three-phase power AC output, three sets of exactly the same single-phase inversion, filtering, and voltage transformation circuits are combined. The outputs of the three circuits have a phase angle difference of 120°. The circuits are electrically isolated from each other on the primary side of the transformer and are connected in a Y shape on the secondary side of the output transformer to output three-phase four-wire alternating current. The AC voltages output by the three single-phase bridge inverters are distributed according to a phase angle of 120° and are independent of each other on the primary side of the output transformer, forming a fully controlled bridge three-phase inverter. A three-phase four-wire AC voltage with a common connection point is formed on the secondary side of the output transformer. This structure can reduce the impact on the system output voltage caused by unbalanced loads at the output end, ensuring that the system can adapt to any unbalanced load, expanding the load adaptability and application range of the system.

[0050] 2. Energy storage cabinet part

[0051] The energy storage cabinet part is the architecture of an intelligent energy storage emergency power supply system. The intelligent energy storage emergency power supply system mainly consists of a static transfer switch, a transformer, a battery energy storage converter, a battery management system, and a battery cluster system. The battery energy storage converter mainly realizes the energy exchange between the battery and the power grid and controls and manages the charging and discharging of the battery. The static transfer switch automatically switches to realize the on-grid and off-grid of the system. The transformer has an isolation function to eliminate the common-mode voltage of the battery energy storage converter under off-grid conditions. The voltage of N to PE is 0, meeting the safety regulations requirements. The battery management system mainly collects the voltage and current of the battery system and protects the battery system, etc.

[0052] The system operation modes include grid-connected charging mode and off-grid discharging mode. The grid-connected charging mode means that the power supply circuit connected to the intelligent emergency power supply cabinet is normal. At this time, the battery energy storage converter is in the grid-connected charging mode. The off-grid discharging mode means that the power supply circuit connected to the intelligent emergency power supply cabinet is abnormal. At this time, the battery energy storage converter is in the off-grid discharging mode, providing voltage and frequency support for electrical equipment.

[0053] The grid-side voltage sampling and load-side voltage sampling of the static transfer switch support single-phase detection and three-phase detection. When a fault such as a phase loss occurs in any phase (the fault threshold is configurable, for example, the voltage judgment usually uses 20% of the rated value as the fault detection threshold), the energy storage cabinet can identify the fault type and upload the fault type to the energy management system and the power telecontrol background. When the 27.5KV railway power supply is abnormal (single-phase abnormality or three-phase abnormality) or power-off occurs, seamless switching between grid connection and off-grid is achieved, and power is supplied to the load under off-grid conditions.

[0054] In addition, the energy storage cabinet part also includes uninterruptible power supply, monitoring, distribution switch, fault recording and fire protection, etc.

Claims

1. A railway backup power supply system based on AC-DC-AC purification and energy storage power supply, characterized in that, It includes an AC-DC-AC power supply device (1) and an energy storage power supply device (2); the 27.5 kV catenary power supply (31) of the railway first passes through the AC-DC-AC power supply device (1) for processing and is output to the energy storage power supply device (2). The AC-DC-AC power supply device (1) includes an AC-DC-AC purification power supply (11) and an isolation transformer (12); the AC-DC-AC power supply device (1) adopts a topological structure of a rectifier circuit + an inverter circuit; the 27.5 kV catenary power supply (31) of the railway is sequentially connected to the AC-DC-AC purification power supply (11) and the isolation transformer (12) through a single-phase transformer (32). The energy storage power supply device (2) includes an anti-backfeeding power supply device (21), a static transfer switch module (22), an energy storage converter module (23), an energy storage module (24), and an energy storage management system (25). The 27.5 kV catenary power supply (31) of the railway is sequentially connected to the anti-backfeeding power supply device (21), the energy storage converter module (23), and the energy storage module (24) through the AC-DC-AC power supply device (1). The 27.5 kV catenary and the 10 kV through line power supply are connected in parallel through the static transfer switch module (22), and the static transfer switch module (22) realizes the automatic switching and off-grid of the 10 kV through line power supply (41) and the 27.5 kV catenary power supply (31). The energy storage converter module (23) is a converter that realizes bidirectional power conversion between the energy storage module (24) and the power grid or load; the energy storage converter module (23) realizes the energy exchange between the energy storage module (24) and the power grid through the battery management system, and controls and manages the charging and discharging of the energy storage module (24). The energy storage management system is responsible for monitoring battery data and protecting battery safety; it realizes the internal energy control of the system through data acquisition, network monitoring, and energy scheduling to ensure the normal operation of the whole system.

2. The railway emergency power supply system based on the AC-DC-AC purification and energy storage power supply according to claim 1, characterized in that, The input of the AC-DC-AC power supply device (1) is connected to the 0.23 kV side of the 27.5 kV step-up transformer. After being transformed by the AC-DC-AC power supply device (1), it realizes single-phase split-phase three-phase output and outputs a stable 0.4 kV AC power supply required for communication and signals.

3. The railway backup power system based on the AC-DC-AC purification and energy storage power supply according to claim 1, wherein, The rectifier circuit of the AC-DC-AC power supply device (1) consists of a single-phase bridge rectifier and a filter circuit. The AC power input is processed by the single-phase bridge rectifier and the corresponding filter circuit and is transformed into a DC voltage with an amplitude of about 150 V, initially suppressing the large fluctuations and harmonic effects of the catenary voltage. The inverter circuit of the AC-DC-AC power supply device (1) consists of three parts: inversion, filtering, and transformation. The inversion part adopts a single-phase full-bridge structure; the inverter circuit consists of three single-phase fully controlled bridge inverters with exactly the same structure and isolated from each other and an output transformer, forming a three-phase circuit.

4. The railway standby power supply system based on AC-DC-AC purification and energy storage power supply according to claim 1, characterized in that, The energy storage power supply device (2) also includes a low-voltage dual-power supply switching device.

5. The railway standby power supply system based on AC-DC-AC purification and energy storage power supply according to claim 1, characterized in that, The operation modes of the energy storage power supply device (2) include a grid-connected charging mode and an off-grid discharging mode. The grid-connected charging mode means that the power supply circuit to which the energy storage power supply device (2) is connected is powered normally, and at this time, the energy storage converter module (23) is in the grid-connected charging mode; the off-grid discharging mode means that the power supply circuit to which the energy storage power supply device (2) is connected is abnormally powered, and at this time, the energy storage converter module (23) is in the off-grid discharging mode to provide voltage and frequency support for the electrical equipment.

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