A rail transit energy storage power supply system and method

Abstract

This invention provides a rail transit energy storage power supply system and method, relating to the rail transit field. The system includes a DC traction energy storage system, which is connected to an AC medium-voltage bus, a bidirectional converter, and a new energy power generation system via switches; a medium-voltage ring network energy storage system, which includes, in sequence, the AC medium-voltage energy storage section of a first traction step-down hybrid substation, a second traction step-down hybrid substation, a step-down substation, an inter-substation AC medium-voltage ring network, and a remote DC traction network; and a new energy energy storage system, which includes a first new energy power generation system, which is connected to a DC traction bus, a bidirectional converter, and a 0.4kV bus via switches. This invention addresses the technical problems of insufficient energy efficiency optimization, limited emergency response capabilities, and increased equipment redundancy costs in existing systems.

Description

Technical Field

[0001] This invention relates to the field of rail transit, and more specifically, to a rail transit energy storage power supply system and method. Background Technology

[0002] Currently, energy storage devices for rail transit mainly employ capacitor energy storage or flywheel energy storage. These devices typically absorb regenerative braking energy from locomotives via a DC traction bus (DC 1500V / 750V). Traction substations are equipped with 1-2 traction rectifier units connected to the medium-voltage ring network and the DC bus, with the energy storage device connected to the DC traction bus to achieve energy recovery within a single substation. However, existing technologies have significant drawbacks: First, energy storage systems are limited to the power supply range of a single substation, making it difficult to share energy or coordinate dispatch across substations; second, they cannot be integrated with new energy generation systems, meaning that energy storage and new energy cannot jointly power emergency loads (locomotives, power lighting, etc.) during power outages, and there is a lack of flexible emergency power supply paths via the medium-voltage ring network; third, energy storage devices and power quality management equipment operate independently, resulting in functional fragmentation and low resource reuse rates. These problems lead to insufficient system energy efficiency optimization, limited emergency response capabilities, and increased equipment redundancy costs, hindering the intensive and intelligent development of rail transit energy systems. Summary of the Invention

[0003] The purpose of this invention is to provide a rail transit energy storage power supply system and method to improve the above-mentioned problems. To achieve the above objective, the technical solution adopted by this invention is as follows:

[0004] A rail transit energy storage power supply system includes:

[0005] A DC traction energy storage system, wherein the DC traction energy storage system is connected to an AC medium-voltage bus, a bidirectional converter and a new energy power generation system via switches respectively;

[0006] The medium-voltage ring network energy storage system includes the AC medium-voltage energy storage section of the first traction step-down hybrid substation, the second traction step-down hybrid substation, the step-down substation, the inter-substation AC medium-voltage ring network, and the remote DC traction network, which are connected in sequence.

[0007] The AC medium-voltage energy storage section of the first traction step-down hybrid substation is connected to the AC medium-voltage ring network, traction rectifier unit, and new energy power generation system via a switch; one side of the second traction step-down hybrid substation is connected to the AC medium-voltage ring network via a switch, and the other side is connected to the DC traction network via a switch; the step-down substation is connected to the AC medium-voltage ring network via a switch.

[0008] A new energy storage system, comprising a first new energy power generation system, wherein the first new energy power generation system is connected to a DC traction bus, a bidirectional converter, and a 0.4kV bus via a switch;

[0009] An energy storage device is connected to a DC traction energy storage system, a medium-voltage ring network energy storage system, and a new energy energy storage system via switches.

[0010] On the other hand, the present invention proposes a method for energy storage power supply in rail transit, the method comprising:

[0011] S1. Obtain the operating mode of the first traction step-down hybrid substation, and determine the incoming power supply line based on the operating mode:

[0012] S2. Determine if the incoming voltage on the power supply side is normal:

[0013] If not, then perform a power switch and determine whether the backup power supply has been successfully put into operation;

[0014] If so, the DC traction bus voltage is obtained, and the energy storage device is controlled to charge and discharge based on the DC traction bus voltage, charging voltage threshold, and discharging voltage threshold.

[0015] S3. Obtain the incoming current and AC medium voltage bus voltage on the power supply side to calculate the incoming power, negative sequence, harmonics, and reactive power on the power supply side.

[0016] When the incoming power on the power supply side is greater than 0, the energy storage device is controlled to discharge; when the incoming power on the power supply side is equal to 0, the energy storage device is controlled to maintain the current power level; when the incoming power on the power supply side is less than 0, the energy storage device is controlled to charge. When the negative sequence, harmonics, and reactive power of the incoming power supply side do not meet the requirements of the incoming power supply side, the negative sequence, harmonics, and reactive power that need to be compensated are calculated, and the negative sequence, harmonics, reactive power, and energy charging and discharging of the incoming power supply side are comprehensively processed through the bidirectional converter.

[0017] S4. Obtain the power generation of each new energy power generation system and the power consumption of the new energy power supply load, and determine the magnitude of the power generation and power consumption:

[0018] If the power generation is less than the power consumption, the renewable energy power generation system will supply power to the renewable energy load. The power difference between the power consumption and the power generation will be supplemented to the renewable energy load by the AC medium-voltage ring network, distribution transformer, or energy storage device.

[0019] If the power generation capacity equals the power consumption capacity, then the new energy power generation system supplies power to the new energy power supply load;

[0020] If the power generation capacity exceeds the power consumption capacity, the new energy power generation system supplies power to the new energy power supply load, and the excess power of the new energy power generation system supplies power to the AC medium-voltage ring network and energy storage devices; the beneficial effects of this invention are:

[0021] 1. The present invention provides multiple traction step-down hybrid substations and step-down substations set up in rail transit sections, which can realize shared energy storage for traction power supply, regenerative braking and energy storage through AC medium-voltage ring network and / or DC traction bus, and can realize shared energy storage for new energy power generation through AC medium-voltage ring network, thereby improving energy utilization efficiency.

[0022] 2. This invention enables energy storage devices and new energy power generation systems to provide emergency power to loads such as emergency locomotives and emergency lighting when a power outage occurs within a section. Furthermore, depending on the line load characteristics, emergency power supply can be provided via a DC traction bus or a medium-voltage ring network, improving the system's emergency power supply capability and enhancing its reliability and flexibility. Additionally, this invention allows for the shared use of energy storage devices and power quality management devices within a section, reducing equipment investment.

[0023] Other features and advantages of the invention will be set forth in the following description, and in part will be obvious from the description or may be learned by means of embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 One type of energy storage power supply system for rail transit;

[0026] Figure 2 For rail transit energy storage power supply system II;

[0027] Figure 3 For rail transit energy storage power supply system three;

[0028] Figure 4 This describes the control method for the first traction step-down hybrid substation when the power supply voltage is normal.

[0029] Figure 5 Emergency power supply control method after power failure;

[0030] Figure 6 This describes the control method for the second traction step-down hybrid substation when the power supply voltage is normal. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] Example 1:

[0034] like Figure 1 As shown, a rail transit energy storage power supply system includes:

[0035] A DC traction energy storage system is connected to an AC medium-voltage bus, a bidirectional converter, and a new energy power generation system via switches. The incoming switches for the AC medium-voltage bus are 101 and 102.

[0036] The medium-voltage ring network energy storage system includes the AC medium-voltage energy storage section of the first traction step-down hybrid substation (A), the second traction step-down hybrid substation (B), the step-down substation (C), the inter-substation AC medium-voltage ring network, and the remote DC traction network, which are connected in sequence.

[0037] The AC medium-voltage energy storage section of the first traction step-down hybrid substation is connected to the AC medium-voltage ring network, traction rectifier unit, and new energy power generation system via a switch; one side of the second traction step-down hybrid substation is connected to the AC medium-voltage ring network via a switch, and the other side is connected to the DC traction network via a switch; the step-down substation is connected to the AC medium-voltage ring network via a switch; wherein, the first traction step-down hybrid substation, the second traction step-down hybrid substation, and the step-down substation are respectively equipped with AC medium-voltage bus incoming switches 101 and 102;

[0038] A new energy storage system, comprising a first new energy power generation system, wherein the first new energy power generation system is connected to a DC traction bus, a bidirectional converter, and a 0.4kV bus via a switch;

[0039] The energy storage device is connected to the DC traction energy storage system, the medium-voltage ring network energy storage system, and the new energy energy storage system through the DC traction energy storage switch 203, the medium-voltage ring network energy storage switch 202, and the new energy power generation system energy storage switch 204, respectively. Therefore, the first traction step-down hybrid substation is an energy storage substation, and the second traction step-down hybrid substation and the step-down substation are non-energy storage substations.

[0040] Based on the above embodiments, the DC traction energy storage system includes a first traction rectifier unit, a first DC feeder switch 211 and / or 212 and / or 213 and / or 214, a DC traction energy storage switch 203, an energy storage device, and a DC traction network. Specifically, one side of the first traction rectifier unit is connected to the AC medium-voltage bus via the rectifier unit feeder switch 103, and the other side is connected to the DC traction bus via the DC incoming switch 201. The DC traction energy storage switch is connected to the first DC feeder switch, the DC traction bus, and the energy storage device, respectively. The first DC feeder switch is connected to the DC traction energy storage switch, the first traction rectifier unit, the DC traction bus, and the DC traction network, respectively.

[0041] Based on the above embodiments, the AC medium-voltage energy storage section of the first traction step-down hybrid substation includes a first bidirectional converter, an energy storage device, an AC medium-voltage bus, a first distribution transformer, a 0.4kV bus, low-voltage loads, and related connected circuit breakers, current transformers, shunts, voltage transformers, etc. One side of the first bidirectional converter is connected to the AC medium-voltage bus via a circuit switch 104, and the other side is connected to the energy storage device via a medium-voltage ring network energy storage switch 202; one side of the first distribution transformer is connected to the AC medium-voltage ring network via a medium-voltage AC switch 105, and the other side is connected to the low-voltage load.

[0042] Based on the above embodiments, the second traction step-down hybrid substation includes a second traction rectifier unit, a second bidirectional converter device, a second distribution transformer circuit, and related connected circuit breakers, current transformers, shunts, voltage transmitters, voltage transformers, etc.; one side of the second traction rectifier unit and the second bidirectional converter device are respectively connected to the AC medium-voltage ring network through switches, and the other side is respectively connected to the DC traction network through switches.

[0043] Specifically, one side of the second traction rectifier unit is connected to the AC medium-voltage ring network through the rectifier unit feeder switch 103, and the other side is connected to the DC traction bus and the second DC feeder switch through the DC incoming switch 201; one side of the second bidirectional converter is connected to the AC medium-voltage ring network through the bidirectional converter circuit AC switch 104, and the other side is connected to the energy storage device through the medium-voltage ring network energy storage switch 202; one side of the second distribution transformer is connected to the AC medium-voltage ring network through the medium-voltage AC switch 105, and the other side is connected to the low-voltage load.

[0044] Based on the above embodiments, the step-down substation includes a second new energy power generation system, a third distribution transformer circuit, and related circuit breakers, current transformers, voltage transformers, etc. The third distribution transformer is connected to the AC medium-voltage ring network on one side through a medium-voltage AC switch 105, and connected to the low-voltage load on the other side through a switch. The second new energy power generation system is connected to the low-voltage load through a switch.

[0045] Specifically, the energy storage / discharge method of the DC traction energy storage system is as follows:

[0046] The following switches are sequentially closed: AC medium-voltage bus power supply incoming switch 101 or 102, medium-voltage bus rectifier unit feeder switch 103, DC traction network energy storage switch 203, DC traction bus incoming switch 201, first DC feeder switches 211, 212, 213, 214, and other related switches. When the train brakes, the DC 1500V or DC 750V DC traction bus voltage rises. When the voltage rises to the charging voltage threshold, the coordinating controller controls the energy storage device to absorb braking energy; when the voltage is lower than the discharge voltage threshold, the coordinating controller controls the energy storage device to discharge.

[0047] Specifically, the energy storage / discharge method of the medium-voltage ring network energy storage system is as follows:

[0048] Close the AC medium-voltage bus power supply incoming switch 101 and / or 102, the bidirectional converter switch 104, the distribution transformer circuit 105, the medium-voltage ring network energy storage switch 202, and other relevant switches required for the first traction step-down hybrid substation. Close the power supply incoming switches 101 and 102, the rectifier unit feeder switch 103, the converter feeder AC switch 104, the distribution transformer switch 105, and the relevant switches for the DC traction power supply circuit, distribution circuit, and new energy power supply circuit for the second traction step-down hybrid substation and the step-down substation. Then, the corresponding locomotive regenerative braking energy, surplus new energy power generation in the second traction step-down hybrid substation, and surplus new energy power generation in the step-down substation can be fed into the AC medium-voltage ring network. The fed-in energy is absorbed by other loads through the medium-voltage ring network (if there are other loads, the absorbed energy is determined according to the project situation), and excess energy is stored in the energy storage device through the medium-voltage ring network.

[0049] Specifically, the energy storage / discharge methods of new energy storage systems are as follows:

[0050] Closing the energy storage switch 204 and other related switches of the first new energy power generation system enables the first new energy power generation system to store energy in the energy storage device; closing the AC medium voltage bus power supply incoming switches 101 and / or 102 of the first traction step-down hybrid substation, the second traction step-down hybrid substation and the step-down substation, the new energy substation distribution switch 105, the new energy circuit switch and other related switches enables the second new energy power generation system to store energy in the energy storage device through the medium voltage ring network.

[0051] Example 2:

[0052] like Figure 2 As shown, a rail transit energy storage power supply system includes:

[0053] A DC traction energy storage system is connected to an AC medium-voltage bus, a bidirectional converter, and a new energy power generation system via switches. The incoming switches for the AC medium-voltage bus are 101 and 102.

[0054] The medium-voltage ring network energy storage system includes an AC medium-voltage energy storage section of a step-down substation (A), a first traction step-down hybrid substation (B), a second traction step-down hybrid substation (C), an inter-substation AC medium-voltage ring network, and a remote DC traction network, all connected in sequence.

[0055] The AC medium-voltage energy storage section of the first traction step-down hybrid substation is connected to the AC medium-voltage ring network, traction rectifier unit, and new energy power generation system via a switch; one side of the second traction step-down hybrid substation is connected to the AC medium-voltage ring network via a switch, and the other side is connected to the DC traction network via a switch; the step-down substation is connected to the AC medium-voltage ring network via a switch; wherein, the first traction step-down hybrid substation, the second traction step-down hybrid substation, and the step-down substation are respectively equipped with AC medium-voltage bus incoming switches 101 and 102;

[0056] A new energy storage system, comprising a first new energy power generation system, wherein the first new energy power generation system is connected to a DC traction bus, a bidirectional converter, and a 0.4kV bus via a switch;

[0057] The energy storage device is connected to the DC traction energy storage system, the medium-voltage ring network energy storage system, and the new energy energy storage system through the DC traction network energy storage switch 203, the medium-voltage ring network energy storage switch 202, and the new energy power generation system energy storage switch 204, respectively. Therefore, the first traction step-down hybrid substation is an energy storage substation, and the second traction step-down hybrid substation and the step-down substation are non-energy storage substations.

[0058] Based on the above embodiments, the DC traction energy storage system includes a first traction rectifier unit, a first DC feeder switch 211 and / or 212 and / or 213 and / or 214, a DC traction energy storage switch 203, an energy storage device, and a DC traction network. Specifically, one side of the first traction rectifier unit is connected to the AC medium-voltage bus via the rectifier unit feeder switch 103, and the other side is connected to the DC traction bus via the DC incoming switch 201. The first DC feeder switch is connected to the DC traction bus, the DC traction energy storage switch, the first traction rectifier unit, and the DC traction network, respectively. The DC traction energy storage switch is connected to the first DC feeder switch, the DC traction bus, and the energy storage device, respectively.

[0059] Based on the above embodiments, the AC medium-voltage energy storage section of the first traction step-down hybrid substation includes a first bidirectional converter, an energy storage device, an AC medium-voltage bus, a first distribution transformer, a 0.4kV bus, low-voltage loads, and related connected circuit breakers, current transformers, shunts, voltage transformers, etc. One side of the first bidirectional converter is connected to the AC medium-voltage bus via a circuit switch 104, and the other side is connected to the energy storage device via a medium-voltage ring network energy storage switch 202; one side of the first distribution transformer is connected to the AC medium-voltage ring network via a medium-voltage AC switch 105, and the other side is connected to the low-voltage load.

[0060] Based on the above embodiments, the second traction step-down hybrid substation includes a second traction rectifier unit, an inverter feedback device, a second distribution transformer circuit, and related connected circuit breakers, current transformers, shunts, voltage transmitters, voltage transformers, etc. One side of the second traction rectifier unit and the inverter feedback device are respectively connected to the AC medium-voltage ring network through switches, and the other side is respectively connected to the DC traction bus through switches.

[0061] Specifically, one side of the second traction rectifier unit is connected to the AC medium-voltage ring network through the rectifier unit feeder switch 103, and the other side is connected to the DC traction bus and the second DC feeder switch through the DC incoming switch 201; one side of the inverter feedback device is connected to the AC medium-voltage ring network through the inverter feedback circuit AC switch 104, and the other side is connected to the DC traction network through the inverter feedback circuit DC switch 202; one side of the second distribution transformer is connected to the AC medium-voltage ring network through the medium-voltage AC switch 105, and the other side is connected to the low-voltage load through a switch.

[0062] Based on the above embodiments, the step-down substation includes a second new energy power generation system, a third distribution transformer circuit, and related connected circuit breakers, current transformers, voltage transformers, etc. The second new energy power generation system is connected to the low-voltage load through a switch.

[0063] Example 3:

[0064] like Figure 3As shown, a rail transit energy storage power supply system includes:

[0065] A DC traction energy storage system, wherein the DC traction energy storage system is connected to an AC medium-voltage bus and a new energy power generation system respectively via switches;

[0066] The medium-voltage ring network energy storage system includes, in sequence, a step-down substation, an AC medium-voltage energy storage section of a first traction step-down hybrid substation, a second traction step-down hybrid substation, an inter-substation AC medium-voltage ring network, and a remote DC traction network.

[0067] The AC medium-voltage energy storage section of the first traction step-down hybrid substation is connected to the AC medium-voltage ring network and the new energy power generation system via a switch; one side of the second traction step-down hybrid substation is connected to the AC medium-voltage ring network via a switch, and the other side is connected to the DC traction network via a switch; the step-down substation is connected to the AC medium-voltage ring network via a switch.

[0068] A new energy storage system, comprising a first new energy power generation system, wherein the first new energy power generation system is connected to a DC traction bus, a bidirectional converter, and a 0.4kV bus via a switch;

[0069] The energy storage device is connected to a DC traction energy storage system, a medium-voltage ring network energy storage system, and a new energy energy storage system via switches.

[0070] Based on the above embodiments, the DC traction energy storage system includes a first bidirectional converter, a first DC feeder switch 211 and / or 212 and / or 213 and / or 214, a first energy storage switch 203, an energy storage device, and a DC traction network; wherein, the first DC feeder switch is connected to the DC traction bus, the first bidirectional converter, the energy storage device, and the DC traction network respectively, and the first energy storage switch is connected to the first DC feeder switch, the DC traction bus, the first bidirectional converter, and the energy storage device respectively.

[0071] Based on the above embodiments, the AC medium-voltage energy storage section of the first traction step-down hybrid substation includes a first bidirectional converter, an energy storage device, an AC medium-voltage bus, a first distribution transformer, a 0.4kV bus, low-voltage loads, and related circuit breakers, current transformers, shunts, voltage transformers, etc. One side of the first bidirectional converter is connected to the AC medium-voltage bus via a circuit switch 103, and the other side is connected to the DC traction bus via a DC incoming switch 201; one side of the first distribution transformer is connected to the AC medium-voltage ring network via a medium-voltage AC switch 105, and the other side is connected to the low-voltage load.

[0072] Based on the above embodiments, the second traction step-down hybrid substation includes a second bidirectional converter, a second distribution transformer, and related circuit breakers, current transformers, shunts, voltage transmitters, and voltage transformers; one side of the second bidirectional converter is connected to the AC medium-voltage ring network through a switch, and the other side is connected to the DC traction bus through a switch;

[0073] Specifically, one side of the second bidirectional converter is connected to the AC medium-voltage ring network through the bidirectional converter AC switch 103, and the other side is connected to the second DC feeder switch through the DC input switch 201; one side of the second distribution transformer is connected to the AC medium-voltage ring network through the medium-voltage AC switch 105, and the other side is connected to the low-voltage load through a switch.

[0074] Based on the above embodiments, the step-down substation includes a second new energy power generation system and a third distribution transformer, as well as related circuit breakers, current transformers, voltage transformers, etc. The third distribution transformer is connected to the AC medium-voltage busbar on one side through a medium-voltage AC switch 105, and connected to the low-voltage load on the other side through a switch. The second new energy power generation system is connected to the low-voltage load through a switch.

[0075] Example 4:

[0076] like Figure 4 As shown, a rail transit energy storage power supply method, specifically a control method for the first traction step-down hybrid substation, includes:

[0077] S1. Obtain the operating mode of the first traction step-down hybrid substation, and determine the incoming power supply line based on the operating mode:

[0078] S2. Determine if the incoming voltage on the power supply side is normal:

[0079] If not, then perform a power switchover and determine whether the backup power supply has been successfully activated:

[0080] If so, the DC bus voltage is obtained, and the energy storage device is controlled to charge and discharge based on the DC bus voltage, charging voltage threshold, and discharging voltage threshold.

[0081] S3. Obtain the incoming current and AC medium voltage bus voltage on the power supply side to calculate the incoming power, negative sequence, harmonics, and reactive power on the power supply side.

[0082] When the incoming power on the power supply side is greater than 0, it is in power supply mode and the energy storage device needs to be controlled to discharge; when the incoming power on the power supply side is equal to 0, it is in no-load mode and the energy storage device needs to be controlled to maintain the current power level; when the incoming power on the power supply side is less than 0, it is in energy feeding mode and the energy storage device needs to be controlled to charge.

[0083] When the negative sequence, harmonics, and reactive power of the incoming power supply line do not meet the requirements of the incoming power supply line, the negative sequence, harmonics, and reactive power that need to be compensated are calculated, and the negative sequence, harmonics, reactive power, and power charging and discharging of the incoming power supply line are comprehensively processed through a bidirectional converter.

[0084] S4. Obtain the power generation of each new energy power generation system and the power consumption of the new energy power supply load, and determine the magnitude of the power generation and power consumption:

[0085] If the power generation is less than the power consumption, the renewable energy power generation system will supply power to the renewable energy load. The power difference between the power consumption and the power generation will be supplemented to the renewable energy load by the AC medium-voltage ring network, distribution transformer, or energy storage device.

[0086] If the power generation capacity equals the power consumption capacity, then the new energy power generation system supplies power to the new energy power supply load;

[0087] If the power generation capacity exceeds the power consumption capacity, the renewable energy power generation system supplies power to the renewable energy load. When the power input on the power source side is greater than 0, the excess power of the renewable energy power generation system supplies power to the AC medium-voltage ring network; when the power input on the power source side is less than or equal to 0, the excess power of the renewable energy power generation system charges the energy storage device.

[0088] like Figure 5 As shown, based on the above embodiments, the control method further includes:

[0089] S5. When there is no power on the incoming power line, determine the emergency power supply load;

[0090] S6. Obtain the power generation of each new energy power generation system and the power consumption of the new energy emergency power supply load, and determine the magnitude of the power generation and power consumption:

[0091] If the power generation is less than the power consumption, the new energy power generation system will supply power to the new energy emergency power supply load. The power difference between the power consumption and the power generation will be supplemented to the new energy emergency power supply load by the AC medium-voltage ring network, distribution transformer or energy storage device.

[0092] If the power generation capacity equals the power consumption capacity, then the new energy power generation system will supply power to the new energy emergency power supply load;

[0093] If the power generation capacity is greater than the power consumption capacity, the new energy power generation system supplies power to the new energy emergency power supply load, and the excess power of the new energy power generation system supplies power to the AC medium-voltage ring network or energy storage device.

[0094] S7. Sequentially obtain the location and power of the emergency rescue vehicle, the location and available energy storage power of the first traction step-down hybrid substation, the location of the second traction step-down hybrid substation and the step-down substation, obtain the power and location of each new energy station supplying power to the AC medium-voltage ring network, obtain the power and location of the locomotive regenerative energy entering the AC medium-voltage ring network through the feedback device, obtain the power and location of other emergency power loads that need to be supplied by the energy storage device, so as to calculate the power supply path of the energy storage device to the emergency rescue vehicle and determine the power supply path of the energy storage device to other emergency power loads;

[0095] Specifically, the calculation method for the power supply path is as follows:

[0096] S71. Calculate the energy consumption and energy required to directly supply power to emergency rescue vehicles through energy storage devices and DC traction networks;

[0097] S72. Calculate the energy consumption and energy required to supply power to emergency rescue vehicles through energy storage devices, first bidirectional converter devices, AC medium-voltage ring networks, second rectifier units or second bidirectional converter devices, and DC traction networks.

[0098] S73. Compare the energy consumption and energy levels of the two, and reverse the power supply circuit to form a power supply path in the manner of lower energy consumption and higher effective energy.

[0099] S8. Power is supplied to the emergency rescue vehicle from the energy storage device according to the power supply path. The path is also determined to supply power to other emergency power loads from the energy storage device.

[0100] Preferably, it also includes the regenerative energy of the locomotive, which enters the energy storage device through the DC traction bus or through the feedback device into the AC medium-voltage ring network or energy storage device when the locomotive regenerative energy feed-in condition.

[0101] Based on the above embodiments, if the traction emergency power supply is supplied through the DC traction network and is supplied by the new energy power generation system of another substation, the new energy circuit switch of the new energy substation, the relevant medium-voltage ring network incoming line switches 101 and 102 (excluding the switch connecting the medium-voltage ring network to the external power line) within the closed section are closed, the bidirectional converter switch 104, the medium-voltage ring network energy storage switch 202, the new energy power generation system energy storage switch 204 (if the new energy power generation system of the first traction step-down hybrid substation stores energy through switch 204, then this switch is closed), the DC traction network energy storage switch 203 is closed, the longitudinal separation of the contact network between the first traction step-down hybrid substation and the emergency load is closed, the first DC feeder switch and other related switches are closed, and the new energy power generation system and energy storage device provide emergency traction power supply to the vehicle; when there is no new energy power generation system supply, the DC traction network energy storage switch 203 is closed, the longitudinal separation of the contact network between the first traction step-down hybrid substation and the emergency load is closed, the first DC feeder switch and other related switches are closed, and the energy storage device provides emergency traction power supply to the vehicle.

[0102] Based on the above embodiments, if the traction emergency power supply is provided through the AC medium-voltage ring network and is supplied by the new energy power generation system of another station, the new energy circuit switch of the new energy power supply station within the closed section, the relevant AC medium-voltage ring network incoming line switches 101 and 102 (excluding the switch connecting the medium-voltage ring network to the external power line), the bidirectional converter device switch 104 (103 in embodiment three) of the first traction step-down hybrid substation, the medium-voltage ring network energy storage switch 202 (energy storage switch 203 in embodiment three), the new energy power generation system energy storage switch 204 (if the new energy power generation system of the first traction step-down hybrid substation stores energy through switch 204, this switch is closed), the rectifier unit feeder switch 103 of the traction step-down hybrid substation near the emergency rescue vehicle (bidirectional converter feeder switch 103 in embodiment three), and the bidirectional converter or inverter feedback device circuit switch 104 (not present in embodiment three) are closed. The system provides emergency traction power to the vehicle via a new energy power generation system and energy storage device. When no new energy power generation system is available, the system closes the medium-voltage ring network energy storage switch 202 (energy storage switch 203 in Example 3), the bidirectional converter switch 104 (103 in Example 3), and related medium-voltage ring network incoming switches 101 and 102 (excluding switches connecting the medium-voltage ring network to external power lines) of the first traction step-down hybrid substation. It also closes the rectifier unit feeder switch 103 (bidirectional converter feeder switch 103 in Example 3), the bidirectional converter or inverter feedback device circuit 104 (no such switch in Example 3), the DC incoming switch 201, the DC feeder switch, and other related switches of the traction step-down hybrid substation (or traction substation) near the emergency rescue vehicle. The energy storage device then provides emergency traction power to the vehicle.

[0103] Example 5

[0104] like Figure 6 As shown, a rail transit energy storage power supply method, specifically a control method for the second traction step-down hybrid substation, includes:

[0105] S1. Obtain the operating mode of the second traction step-down hybrid substation, and determine the incoming power supply line based on the operating mode:

[0106] S2. Determine if the incoming voltage on the power supply side is normal:

[0107] If not, then perform a power switchover and determine whether the backup power supply has been successfully activated:

[0108] If so, then obtain the combination form of traction rectification;

[0109] S3. If the traction rectification and feedback adopts a combination of bidirectional converter and traction rectifier unit or only a bidirectional converter is set (i.e., Example 1 and Example 3), the medium-voltage AC bus voltage and power supply side incoming current of the second traction step-down hybrid substation are obtained to calculate the negative sequence, harmonics and reactive power of the power supply incoming side.

[0110] S4. When the negative sequence, harmonics, and reactive power of the incoming power supply line do not meet the requirements of the incoming power supply line, calculate the negative sequence, harmonics, and reactive power that need to be compensated.

[0111] S5. The regenerative power of the locomotive is inverted and fed back to the AC medium-voltage ring network through a bidirectional converter.

[0112] S6. Perform comprehensive processing of negative sequence, harmonics, reactive power, and energy feedback on the power supply side incoming line.

[0113] Based on the above embodiments, this method further includes:

[0114] If the traction rectifier adopts a combination of an inverter feedback device and a traction rectifier unit (i.e., Example 2), the regenerated electricity of the locomotive is inverted and fed back to the AC medium-voltage ring network through the inverter feedback device.

[0115] Other details: Specific configurations will be determined based on project conditions. Whether a new energy power generation system is installed in each substation will be determined based on project conditions. The specific form of new energy power generation, such as photovoltaic power generation or other forms, grid connection or non-grid connection, and separate power supply bus, will be determined based on project conditions. Whether the new energy power generation system is connected to the 0.4kV low-voltage bus, the DC traction bus, or the AC medium-voltage bus will be determined based on project conditions. The rectifier feedback system of the traction substation will adopt a rectifier unit + bidirectional converter, a rectifier unit + inverter feedback device, or a separate bidirectional converter or other forms. The specific wiring configuration and the number of each device will be determined based on project conditions. The transformer type in the rectifier unit, bidirectional converter, and inverter feedback device will be determined based on project conditions. Whether the medium-voltage ring network is a single-ring network or a double-ring network will be determined based on project conditions. Whether the external power supply scheme is centralized or decentralized will be determined based on project conditions. The energy storage device will adopt flywheel energy storage, supercapacitor energy storage, battery energy storage, hybrid energy storage, or other energy storage forms. The specific configuration will be determined based on project conditions. The location of the shared energy storage substation—whether it's in the main substation, switching station, or in the middle of the line, or in multiple locations—is determined based on the project specifications. The type, number, and sequence of substations within the section are determined based on the project specifications. Whether and how longitudinal tie switches are installed are determined based on the specific project requirements. The specific location and numbering of switches are determined based on the specific project requirements. The switching sequence should meet relevant regulations and specifications. To illustrate system relationships, not all equipment in the traction step-down hybrid substation and step-down substation is listed in this plan; only the main equipment illustrating system relationships is included. Each substation should be configured according to the specific project requirements. The charging and discharging control of the energy storage device should meet the charging and discharging requirements of the equipment itself.

[0116] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0117] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A rail transit energy storage power supply system, characterized in that, include: A DC traction energy storage system, wherein the DC traction energy storage system is connected to an AC medium-voltage bus, a bidirectional converter and a new energy power generation system via switches respectively; The medium-voltage ring network energy storage system includes the AC medium-voltage energy storage section of the first traction step-down hybrid substation, the second traction step-down hybrid substation, the step-down substation, the inter-substation AC medium-voltage ring network, and the remote DC traction network, which are connected in sequence. The AC medium-voltage energy storage section of the first traction step-down hybrid substation is connected to the AC medium-voltage ring network, traction rectifier unit, and new energy power generation system via a switch; one side of the second traction step-down hybrid substation is connected to the AC medium-voltage ring network via a switch, and the other side is connected to the DC traction network via a switch; the step-down substation is connected to the AC medium-voltage ring network via a switch. A new energy storage system, comprising a first new energy power generation system, wherein the first new energy power generation system is connected to a DC traction bus, a bidirectional converter and a 0.4kV bus via a switch; An energy storage device, which is connected to a DC traction energy storage system, a medium-voltage ring network energy storage system, and a new energy energy storage system via switches; The system is also configured to perform the following steps: Obtain the operating mode of the first traction step-down hybrid substation, and determine the incoming power supply line based on the operating mode: Determine if the incoming voltage on the power supply side is normal: If not, then perform a power switch and determine whether the backup power supply has been successfully put into operation; If so, the DC traction bus voltage is obtained, and the energy storage device is controlled to charge and discharge based on the DC traction bus voltage, charging voltage threshold, and discharging voltage threshold. Obtain the current on the power supply input side and the AC medium voltage bus voltage to calculate the incoming power, negative sequence, harmonics, and reactive power on the power supply input side. When the incoming power on the power supply side is greater than 0, the energy storage device is controlled to discharge; when the incoming power on the power supply side is equal to 0, the energy storage device is controlled to maintain the current power level; when the incoming power on the power supply side is less than 0, the energy storage device is controlled to charge. When the negative sequence, harmonics, and reactive power of the incoming power supply line do not meet the requirements of the incoming power supply line, the negative sequence, harmonics, and reactive power that need to be compensated are calculated, and the negative sequence, harmonics, reactive power, and power charging and discharging of the incoming power supply line are comprehensively processed through a bidirectional converter. When the incoming power line on the power supply side is de-energized, determine the emergency power supply load; Obtain the power generation capacity of each new energy power generation system and the power consumption of the new energy emergency power supply load, and determine the magnitude of the power generation capacity and the power consumption: If the power generation is less than the power consumption, the new energy power generation system will supply power to the new energy emergency power supply load. The power difference between the power consumption and the power generation will be supplemented to the new energy emergency power supply load by the AC medium-voltage ring network, distribution transformer or energy storage device. If the power generation capacity equals the power consumption capacity, then the emergency power supply load will be supplied by the new energy power generation system; If the power generation capacity is greater than the power consumption capacity, the new energy power generation system supplies power to the new energy emergency power supply load, and the excess power of the new energy power generation system supplies power to the AC medium-voltage ring network or energy storage device. The system sequentially acquires the location and power of emergency rescue vehicles, the location and available energy storage power of the first traction step-down hybrid substation, the location of the second traction step-down hybrid substation and the step-down substation, the power and location of each new energy substation supplying power to the AC medium-voltage ring network, the power and location of locomotive regenerative energy entering the AC medium-voltage ring network through the feedback device, the power and location of other emergency power loads that require energy storage devices, calculates the power supply path of the energy storage device to the emergency rescue vehicles, and determines the power supply path of the energy storage device to other emergency power loads. Emergency power is supplied from the energy storage device to emergency rescue vehicles and emergency power loads according to the power supply path.

2. The rail transit energy storage power supply system according to claim 1, characterized in that, The DC traction energy storage system includes a first traction rectifier unit, a first DC feeder switch, a DC traction energy storage switch, an energy storage device, a DC traction network, and circuit breakers, disconnect switches, current transformers, shunts, and voltage transmitters. One side of the first traction rectifier unit is connected to the AC medium-voltage bus via a switch, and the other side is connected to the DC traction bus via a switch. The DC traction energy storage switch is connected to the first DC feeder switch, the DC traction bus, and the energy storage device, respectively. The first DC feeder switch is connected to the DC traction energy storage switch, the DC traction bus, and the DC traction network, respectively.

3. The rail transit energy storage power supply system according to claim 1, characterized in that, The AC medium-voltage energy storage section of the first traction step-down hybrid substation includes a first bidirectional converter, an energy storage device, an AC medium-voltage bus, a first distribution transformer, a 0.4kV bus, low-voltage loads and circuit breakers, current transformers, shunts, and voltage transformers. One side of the first bidirectional converter is connected to the AC medium-voltage bus via a switch, and the other side is connected to the energy storage device via a switch.

4. The rail transit energy storage power supply system according to claim 1, characterized in that, The second traction step-down hybrid substation includes a second traction rectifier unit, a second bidirectional converter, a second power distribution circuit and circuit breaker, current transformers, shunts, voltage transmitters and voltage transformers. One side of the second traction rectifier unit and the second bidirectional converter are respectively connected to the AC medium-voltage ring network through switches, and the other side is connected to the DC traction bus through switches.

5. The rail transit energy storage power supply system according to claim 1, characterized in that, The step-down substation includes a second new energy power generation system, a third power distribution circuit and circuit breaker, current transformers and voltage transformers, with the second new energy power generation system connected to low-voltage loads.

6. The rail transit energy storage power supply system according to claim 1, characterized in that, The medium-voltage ring network energy storage system can also be an AC medium-voltage energy storage section of a step-down substation, a first traction step-down hybrid substation, and a second traction step-down hybrid substation connected in sequence. The second traction step-down hybrid substation includes a second traction rectifier unit, an inverter feedback device, a second distribution circuit and circuit breaker, current transformers, shunts, voltage transmitters, and voltage transformers. One side of the second traction rectifier unit is connected to the AC medium-voltage ring network via a switch, and the other side is connected to the DC traction bus via a switch. One side of the inverter feedback device is connected to the AC medium-voltage ring network via a switch, and the other side is connected to the DC traction bus via a switch.

7. The rail transit energy storage power supply system according to claim 1, characterized in that, The medium-voltage ring network energy storage system can also be the AC medium-voltage energy storage section of the step-down substation, the first traction step-down hybrid substation, and the second traction step-down hybrid substation connected in sequence; wherein, the second traction step-down hybrid substation includes a second bidirectional converter, a second distribution circuit and circuit breaker, current transformer, shunt, voltage transmitter, and voltage transformer, one side of the second bidirectional converter is connected to the AC medium-voltage ring network through a switch, and the other side is connected to the DC traction bus through a switch.

8. The rail transit energy storage power supply system according to claim 7, characterized in that, The DC traction energy storage system may further include a bidirectional converter, a first DC feeder switch, a DC traction energy storage switch, an energy storage device, a DC traction network, and circuit breakers, disconnect switches, current transformers, shunts, and voltage transmitters; wherein the DC traction energy storage switch is connected to the DC traction bus and the energy storage device respectively.

Images