System and method for supplying power to high-capacity motor load through flexible direct current

Abstract

The invention discloses a power supply system and method for loading a high-capacity motor through flexible direct current, and belongs to the technical field of safe and stable operation and control of a high-proportion new energy system. The system comprises a motor load local power supply unit which is used for configuring a photovoltaic and energy storage unit with a preset capacity for a remote area without a power grid where a motor load is located, so that the motor load is connected with the photovoltaic and energy storage unit through an alternating current line to construct a local power supply network, in the local power supply network, power is supplied to the motor load through photovoltaic and energy storage; the regional alternating-current power grid unit is used for connecting the local power supply network with an alternating-current power grid to form a regional alternating-current power grid; and the unit for supplying power to the remote high-capacity motor load through the flexible direct current is used for constructing a three-terminal flexible direct current power grid based on the regional alternating current power grid, the flexible direct current converter station and the long-distance direct current line and connecting the three-terminal flexible direct current power grid to an alternating current main grid. According to the invention, obvious economic benefits can be created.

Description

Technical Field

[0001] The present invention relates to the technical field, and more particularly, to a power supply system and method for supplying power to a large-capacity motor load via flexible direct current. Background Art

[0002] At present, my country is building a new power system, one of its typical characteristics is that the proportion of new energy is constantly increasing. In extreme cases, there is a scenario where 100% of the load is powered by new energy. When 100% of the load is powered by new energy, the output of new energy depends on the distribution of wind and light resources, and the reliability of power supply cannot be guaranteed. When there is no wind and no light, there is no electricity available, which may eventually lead to power outages. Summary of the invention

[0003] In view of the above problems, the present invention proposes a power supply system for supplying a large-capacity motor load via flexible direct current, comprising:

[0004] A motor load local power supply unit is used to configure photovoltaic and energy storage with preset capacity for remote areas without power grid where the motor load is located, so that the motor load is connected to the photovoltaic and energy storage through an AC line to build a local power supply network, and the motor load is powered by the photovoltaic and energy storage in the local power supply network;

[0005] A regional AC power grid unit, used to connect the local power supply network to the AC power grid to form a regional AC power grid;

[0006] The flexible DC is used to supply power to remote large-capacity motor load units, thereby building a three-terminal flexible DC grid based on the regional AC grid, the flexible DC converter station and the long-distance DC line, and connecting the three-terminal flexible DC grid to the AC main grid.

[0007] Optionally, photovoltaics are used to power motor loads during the day and to charge energy storage.

[0008] Optionally, the power PM of the motor load, the photovoltaic output Pv and the energy storage power Pst in the motor load local power supply unit meet the following requirements:

[0009] Pv+Pst=PM.

[0010] Optionally, the motor load rated capacity PMr, photovoltaic capacity Pvr and energy storage capacity Pstr in the motor load local power supply unit meet the following requirements:

[0011] Pvr:PMr=5:1, Pstr:PMr=3:1.

[0012] Optionally, multiple motor load local power supply units are connected to the regional AC power grid. If any one of the multiple motor load local power supply units has insufficient power supply or failure in photovoltaic and energy storage, power is supplied by other motor load local power supply units among the multiple motor load local power supply units.

[0013] Optionally, the total power in the regional AC grid needs to be balanced, satisfying the following:

[0014] ∑PvA+∑PstA=∑PMA.

[0015] Optionally, the regional AC power grid includes: a regional AC power grid A and a regional AC power grid B;

[0016] When there is a power shortage in the regional AC grid A and / or the regional AC grid B, power can be obtained from the main grid through flexible DC.

[0017] When there is a power surplus in the regional AC grid A and / or the regional AC grid B, electricity can be transmitted to the AC main grid via flexible DC.

[0018] In another aspect, the present invention further provides a method for supplying power to a power supply system for a large-capacity motor load via a flexible direct current, comprising:

[0019] Based on the motor load local power supply unit, photovoltaic and energy storage with preset capacity are configured for the remote area without power grid where the motor load is located, so that the motor load is connected to the photovoltaic and energy storage through an AC line to build a local power supply network, and the motor load is powered by the photovoltaic and energy storage in the local power supply network;

[0020] Connecting the local power supply network to the AC power grid based on the regional AC power grid unit to form a regional AC power grid;

[0021] Based on supplying power to remote large-capacity motor load units via flexible direct current, a three-terminal flexible direct current grid is constructed through the regional AC grid flexible direct current converter station and long-distance DC lines, and the three-terminal flexible direct current grid is connected to the AC main grid.

[0022] Optionally, photovoltaics are used to power motor loads during the day and to charge energy storage.

[0023] Optionally, the power PM of the motor load, the photovoltaic output Pv and the energy storage power Pst in the motor load local power supply unit meet the following requirements:

[0024] Pv+Pst=PM.

[0025] Optionally, the motor load rated capacity PMr, photovoltaic capacity Pvr and energy storage capacity Pstr in the motor load local power supply unit meet the following requirements:

[0026] Pvr:PMr=5:1, Pstr:PMr=3:1.

[0027] Optionally, multiple motor load local power supply units are connected to the regional AC power grid. If any one of the multiple motor load local power supply units has insufficient power supply or failure in photovoltaic and energy storage, power is supplied by other motor load local power supply units among the multiple motor load local power supply units.

[0028] Optionally, the total power in the regional AC grid needs to be balanced, satisfying the following:

[0029] ∑PvA+∑PstA=∑PMA.

[0030] Optionally, the regional AC power grid includes: a regional AC power grid A and a regional AC power grid B;

[0031] When there is a power shortage in the regional AC grid A and / or the regional AC grid B, power can be obtained from the main grid through flexible DC.

[0032] When there is a power surplus in the regional AC grid A and / or the regional AC grid B, electricity can be transmitted to the AC main grid via flexible DC.

[0033] In yet another aspect, the present invention further provides a computing device, comprising: one or more processors;

[0034] a processor for executing one or more programs;

[0035] When the one or more programs are executed by the one or more processors, the above-described method is implemented.

[0036] In yet another aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the method described above is implemented.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention provides a power supply system for large-capacity motor loads via flexible direct current, including: a motor load local power supply unit, which is used to configure photovoltaic and energy storage of preset capacity for remote areas without power grid where the motor load is located, so that the motor load is connected to the photovoltaic and energy storage through an AC line to build a local power supply network, and the motor load is powered by the photovoltaic and energy storage in the local power supply network; a regional AC power grid unit, which is used to connect the local power supply network with the AC power grid to form a regional AC power grid; a power supply unit for remote large-capacity motor loads via flexible direct current, which is used to build a three-terminal flexible DC power grid based on the regional AC power grid, a flexible direct current converter station and a long-distance DC line, and connect the three-terminal flexible DC power grid to the AC main grid. The present invention can improve the reliability of power supply to large-capacity motor loads in remote areas without power grid, improve its safe and stable operation capability, and create significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the system of the present invention;

[0040] Figure 2 A schematic diagram of a local power supply unit of an embodiment of the system of the present invention;

[0041] Figure 3 A schematic diagram of a regional AC power grid construction of an embodiment of the system of the present invention;

[0042] Figure 4 This is a structural diagram of a system for supplying power to large-capacity motor loads in remote areas without power grids via flexible direct current in an embodiment of the system of the present invention. DETAILED DESCRIPTION

[0043] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0044] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0045] Embodiment 1:

[0046] The present invention proposes a power supply system 100 for supplying a large-capacity motor load via flexible direct current, such as Figure 1 As shown, including:

[0047] The motor load local power supply unit 101 is used to configure photovoltaic and energy storage with preset capacity for remote areas without power grid where the motor load is located, so that the motor load is connected to the photovoltaic and energy storage through an AC line to build a local power supply network, and the motor load is powered by the photovoltaic and energy storage in the local power supply network;

[0048] A regional AC power grid unit 102, used to connect the local power supply network to the AC power grid to form a regional AC power grid;

[0049] The flexible direct current is used to supply power to the remote large-capacity motor load unit 103, which is used to build a three-terminal flexible direct current grid based on the regional AC grid, the flexible direct current converter station and the long-distance DC line, and connect the three-terminal flexible direct current grid to the AC main grid.

[0050] Among them, photovoltaics are used to power motor loads during the day and to charge energy storage.

[0051] Among them, the power PM of the motor load in the motor load local power supply unit, the photovoltaic output Pv and the energy storage power Pst meet the following requirements:

[0052] Pv+Pst=PM.

[0053] Among them, the motor load rated capacity PMr, photovoltaic capacity Pvr and energy storage capacity Pstr in the motor load local power supply unit meet the following requirements:

[0054] Pvr:PMr=5:1, Pstr:PMr=3:1.

[0055] Among them, multiple motor load local power supply units are connected in the regional AC power grid. If any motor load local power supply unit among the multiple motor load local power supply units has insufficient power supply or failure in photovoltaic and energy storage, power is supplied by other motor load local power supply units among the multiple motor load local power supply units.

[0056] Among them, the total power in the regional AC power grid needs to be balanced and meet the following requirements:

[0057] ∑PvA+∑PstA=∑PMA.

[0058] The regional AC power grid includes: a regional AC power grid A and a regional AC power grid B;

[0059] When there is a power shortage in the regional AC grid A and / or the regional AC grid B, power can be obtained from the main grid through flexible DC.

[0060] When there is a power surplus in the regional AC grid A and / or the regional AC grid B, electricity can be transmitted to the AC main grid via flexible DC.

[0061] The present invention is further described below in conjunction with the construction process of the system:

[0062] Construction of local power supply unit for motor load:

[0063] like Figure 2 As shown in the figure, in the local area where the motor load is located, a certain capacity of photovoltaic and energy storage are configured, and connected through AC lines to form a local power supply network. The photovoltaic is mainly used to supply power to the motor load and charge the energy storage during the day, and the energy storage is mainly used to supply power to the motor load at night. If the power of the motor load is PM, the photovoltaic output is Pv, and the energy storage power is Pst, the local power supply unit satisfies

[0064] Pv+Pst=PM (1)

[0065] The configuration capacity of photovoltaic and energy storage should be a certain multiple of the motor load capacity (for example, photovoltaic capacity is 5 times the load capacity, and energy storage is 3 times the load capacity) to improve the reliability of power supply. Assuming PMr represents the rated capacity of the motor load, Pvr represents the photovoltaic capacity, and Pstr represents the energy storage capacity, the requirements are:

[0066] Pvr:PMr=5:1,Pstr:PMr=3:1 (2)

[0067] Regional AC power grid construction:

[0068] like Figure 3 As shown, on the basis of constructing the local power supply unit for motor load, in order to further improve the power supply reliability, the local power supply units are connected through the AC power grid with a higher voltage level to form a regional AC power grid to achieve power mutual assistance. Different local power supply units in the regional AC power grid are connected through the AC power grid. In the case of insufficient or faulty photovoltaic or spring power supply in the local power supply unit, power can be supplied by other power supply units in the regional AC power grid. The power supply reliability is significantly improved compared with a single power supply unit. The total power in the region needs to be balanced, that is, to meet the following requirements:

[0069] ∑PvA+∑PstA=∑PMA (3)

[0070] Where A represents the regional AC power grid A.

[0071] Construction of a power supply system for remote large-capacity motor loads via flexible DC:

[0072] like Figure 4As shown in the figure, the regional AC grid A and the regional AC grid B are connected to the AC main grid through a three-terminal flexible DC consisting of flexible DC converter station A, flexible DC converter station B, flexible DC converter station C, long-distance DC line AB, and long-distance DC line BC. At this time, the flexible DC introduces a degree of freedom in power balance:

[0073] ∑PvA+∑PstA+PdcA=∑PMA (4)

[0074] ∑PvB+∑PstB+PdcB=∑PMB (5)

[0075] Where A represents regional AC grid A, and B represents regional grid B. Without considering the loss, the flexible DC network is a passive network, and the power of the three flexible DC converter stations meets

[0076] PdcA+PdcB+PdcC=0 (6)

[0077] When there is a power shortage in regional AC grid A and regional AC grid B, electricity can be obtained from the main grid through flexible DC; when there is a power surplus in regional AC grid A and regional AC grid B, electricity can be transmitted to the AC main grid through flexible DC.

[0078] Flexible DC converter stations A and B adopt grid-type control to provide voltage reference for the regional AC power grid. Flexible DC converter station C adopts fixed DC voltage control and is a power balancing node that can stabilize the DC voltage of the three-terminal flexible DC.

[0079] Circuit breakers A1 and B1 can cooperate to isolate faults on DC line AB, and circuit breakers B2 and C1 can cooperate to isolate faults on line BC.

[0080] Embodiment 2:

[0081] The present invention also provides a method for supplying power to a power supply system for a large-capacity motor load via a flexible direct current, comprising:

[0082] Step 1: Based on the motor load local power supply unit, photovoltaic and energy storage with preset capacity are configured for the remote area without power grid where the motor load is located, so that the motor load is connected to the photovoltaic and energy storage through an AC line to build a local power supply network, and the local power supply network supplies power to the motor load through the photovoltaic and energy storage;

[0083] Step 2: connecting the local power supply network to the AC power grid based on the regional AC power grid unit to form a regional AC power grid;

[0084] Step 3: Based on the flexible direct current to the remote large-capacity motor load power supply unit, a three-terminal flexible direct current grid is constructed through the regional AC grid flexible direct current converter station and the long-distance DC line, and the three-terminal flexible direct current grid is connected to the AC main grid.

[0085] Among them, photovoltaics are used to power motor loads during the day and to charge energy storage.

[0086] Among them, the power PM of the motor load in the motor load local power supply unit, the photovoltaic output Pv and the energy storage power Pst meet the following requirements:

[0087] Pv+Pst=PM.

[0088] Among them, the motor load rated capacity PMr, photovoltaic capacity Pvr and energy storage capacity Pstr in the motor load local power supply unit meet the following requirements:

[0089] Pvr:PMr=5:1, Pstr:PMr=3:1.

[0090] Among them, multiple motor load local power supply units are connected in the regional AC power grid. If any motor load local power supply unit among the multiple motor load local power supply units has insufficient power supply or failure in photovoltaic and energy storage, power is supplied by other motor load local power supply units among the multiple motor load local power supply units.

[0091] Among them, the total power in the regional AC power grid needs to be balanced and meet the following requirements:

[0092] ∑PvA+∑PstA=∑PMA.

[0093] The regional AC power grid includes: a regional AC power grid A and a regional AC power grid B;

[0094] When there is a power shortage in the regional AC grid A and / or the regional AC grid B, power can be obtained from the main grid through flexible DC.

[0095] When there is a power surplus in the regional AC grid A and / or the regional AC grid B, electricity can be transmitted to the AC main grid via flexible DC.

[0096] The present invention can improve the reliability of power supply to large-capacity motor loads in remote areas without power grids, improve their safe and stable operation capabilities, and create significant economic benefits.

[0097] Embodiment 3:

[0098] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of the method in the above embodiment.

[0099] Embodiment 4:

[0100] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both a built-in storage medium in a computer device and an extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the method in the above embodiment.

[0101] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0102] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0103] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0104] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0105] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0106] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A power supply system for large-capacity motor loads via flexible direct current, characterized in that: include: A motor load local power supply unit is used to configure photovoltaic and energy storage with preset capacity for remote areas without power grid where the motor load is located, so that the motor load is connected to the photovoltaic and energy storage through an AC line to build a local power supply network, and the motor load is powered by the photovoltaic and energy storage in the local power supply network; A regional AC power grid unit, used to connect the local power supply network to the AC power grid to form a regional AC power grid; The flexible DC is used to supply power to remote large-capacity motor load units, thereby building a three-terminal flexible DC grid based on the regional AC grid, the flexible DC converter station and the long-distance DC line, and connecting the three-terminal flexible DC grid to the AC main grid.

2. The power supply system according to claim 1, characterized in that: The photovoltaics are used to power the motor load during the day and to charge the energy storage.

3. The power supply system according to claim 1, characterized in that: The motor load power PM, photovoltaic output Pv and energy storage power Pst in the motor load local power supply unit meet the following requirements: Pv+Pst=PM.

4. The power supply system according to claim 1, characterized in that: The motor load rated capacity PMr, photovoltaic capacity Pvr and energy storage capacity Pstr in the motor load local power supply unit meet the following requirements: Pvr:PMr=5:1, Pstr:PMr=3:

1.

5. The power supply system according to claim 1, characterized in that: A plurality of motor load local power supply units are connected to the regional AC power grid. If photovoltaic and energy storage systems of any one of the plurality of motor load local power supply units are underpowered or fail, power is supplied by other motor load local power supply units of the plurality of motor load local power supply units.

6. The power supply system according to claim 5, characterized in that: The total power in the regional AC power grid needs to be balanced, satisfying the following: ∑PvA+∑PstA=∑PMA.

7. The power supply system according to claim 1, characterized in that: The regional AC power grid includes: a regional AC power grid A and a regional AC power grid B; When there is a power shortage in the regional AC grid A and / or the regional AC grid B, power can be obtained from the main grid through flexible DC. When there is a power surplus in the regional AC grid A and / or the regional AC grid B, electricity can be transmitted to the AC main grid via flexible DC.

8. A method for supplying power to a power supply system for a large-capacity motor load via flexible direct current using any one of claims 1 to 7, characterized in that: include: Based on the motor load local power supply unit, photovoltaic and energy storage with preset capacity are configured for the remote area without power grid where the motor load is located, so that the motor load is connected to the photovoltaic and energy storage through an AC line to build a local power supply network, and the motor load is powered by the photovoltaic and energy storage in the local power supply network; Connecting the local power supply network to the AC power grid based on the regional AC power grid unit to form a regional AC power grid; Based on supplying power to remote large-capacity motor load units via flexible direct current, a three-terminal flexible direct current grid is constructed through the regional AC grid flexible direct current converter station and long-distance DC lines, and the three-terminal flexible direct current grid is connected to the AC main grid.

9. The power supply method according to claim 8, characterized in that: The photovoltaics are used to power the motor load during the day and to charge the energy storage.

10. The power supply method according to claim 8, characterized in that: The motor load power PM, photovoltaic output Pv and energy storage power Pst in the motor load local power supply unit meet the following requirements: Pv+Pst=PM.

11. The power supply method according to claim 8, characterized in that: The motor load rated capacity PMr, photovoltaic capacity Pvr and energy storage capacity Pstr in the motor load local power supply unit meet the following requirements: Pvr:PMr=5:1, Pstr:PMr=3:

1.

12. The power supply method according to claim 8, characterized in that: A plurality of motor load local power supply units are connected to the regional AC power grid. If photovoltaic and energy storage systems of any one of the plurality of motor load local power supply units are underpowered or fail, power is supplied by other motor load local power supply units of the plurality of motor load local power supply units.

13. The power supply method according to claim 12, characterized in that: The total power in the regional AC power grid needs to be balanced, satisfying the following: ∑PvA+∑PstA=∑PMA.

14. The power supply method according to claim 8, characterized in that: The regional AC power grid includes: a regional AC power grid A and a regional AC power grid B; When there is a power shortage in the regional AC grid A and / or the regional AC grid B, power can be obtained from the main grid through flexible DC. When there is a power surplus in the regional AC grid A and / or the regional AC grid B, electricity can be transmitted to the AC main grid via flexible DC.

15. A computer device, characterized in that: include: one or more processors; a processor for executing one or more programs; When the one or more programs are executed by the one or more processors, the method according to any one of claims 8 to 14 is implemented.

16. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the method according to any one of claims 8 to 14 is implemented.

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