Cooperative control method for multi-converter system of new energy station

Abstract

The invention relates to the technical field of electric power, and provides a cooperative control method for a multi-converter system of a new energy station, which can deal with a switching failure condition in a process of switching from a grid-connected operation mode to an off-grid operation mode. In a grid-connected operation mode, an energy storage converter of an energy storage system detects whether a power grid has a fault or not; if the power grid breaks down, mode switching is started to switch to an off-grid operation mode; if the mode switching fails, a black start strategy is entered, and in the black start strategy, through an energy storage converter of the energy storage system, in-grid bus voltage is established, a new energy power generation system is started, a load switch is closed, and an off-grid operation mode is entered.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a method, device, computer equipment, storage medium and computer program product for collaborative control of a multi-converter system in a new energy station. Background Art

[0002] Renewable energy power generation replaces traditional fossil energy power generation, and the increasing proportion of new energy power generation in energy consumption is the general trend of energy structure development. Offshore wind power is the field with the greatest potential for large-scale development. The large-scale development and access of new energy such as offshore wind power have brought new challenges to the safe and stable operation of the power grid.

[0003] The energy storage system has superior bidirectional power capability and flexible adjustment characteristics. It can act as an energy buffer in the distribution network, thereby further improving the grid's ability to accept distributed power sources and has broad application prospects.

[0004] The interaction between new energy power generation systems and energy storage systems and the external power grid can include grid-connected operation mode and off-grid operation mode. In the process of switching from grid-connected operation mode to off-grid operation mode, how to deal with the situation of switching failure is a technical problem to be solved. Summary of the invention

[0005] Based on this, it is necessary to provide a method, device, computer equipment, storage medium and computer program product for collaborative control of a multi-converter system in a new energy station to address the above technical problems.

[0006] The present application provides a method for coordinated control of a multi-converter system of a new energy station, the method comprising:

[0007] In the grid-connected operation mode, the energy storage converter of the energy storage system detects whether the grid fails;

[0008] If the power grid fails, a mode switch is initiated to switch to an off-grid operation mode;

[0009] If the mode switching fails, a black start strategy is entered, in which the bus voltage in the grid is established through the energy storage converter of the energy storage system, the new energy power generation system is started, the load switch is closed, and the off-grid operation mode is entered.

[0010] In one embodiment, if the power grid fails, the method further includes:

[0011] The energy storage converter is triggered to disconnect the grid-connected point switch, and the energy storage converter is triggered to switch from the current source mode to the voltage source mode.

[0012] In one of the embodiments, after entering the off-grid operation mode, the method further includes:

[0013] When the power grid is detected to be restored, determining whether the power grid restoration lasts for a set time period;

[0014] If so, the mode switching is initiated to switch to the grid-connected operation mode.

[0015] In one embodiment, if the power grid recovery lasts for a set period of time, the method further includes:

[0016] The energy storage converter is triggered to close the grid-connected point switch.

[0017] In one of the embodiments, in the grid-connected operation mode, the method further includes:

[0018] The output power of the new energy power generation system is taken as the control object, and the output power is smoothed by using the energy storage system so that the output power fluctuates within a set range.

[0019] In one embodiment, the output power of the new energy power generation system is taken as the control object, and the output power is smoothed by using the energy storage system so that the output power fluctuates within a set range, including:

[0020] Obtaining the average output power of the new energy power generation system in a historical period;

[0021] Taking the average output power as a control target, and obtaining a power control instruction according to a difference between the output power of the new energy power generation system and the average output power;

[0022] According to the power control instruction and the energy storage system, the output power is smoothed so that the output power fluctuates within a set range.

[0023] The present application provides a new energy station multi-converter system coordinated control device, the device comprising:

[0024] A power grid detection module is used to detect whether a power grid fault occurs through the energy storage converter of the energy storage system in the grid-connected operation mode;

[0025] A mode switching module, used to initiate mode switching to switch to an off-grid operation mode if a failure occurs in the power grid;

[0026] The black start module is used to enter the black start strategy if the mode switching fails. In the black start strategy, the bus voltage in the grid is established through the energy storage converter of the energy storage system, the new energy power generation system is started, the load switch is closed, and the off-grid operation mode is entered.

[0027] The present application provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the above method.

[0028] The present application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to execute the above method.

[0029] The present application provides a computer program product, on which a computer program is stored, and the computer program is executed by a processor to perform the above method.

[0030] In the above-mentioned new energy station multi-converter system collaborative control method, device, computer equipment, storage medium and computer program product, in the grid-connected operation mode, the energy storage inverter of the energy storage system is used to detect whether a fault occurs in the power grid; if the power grid fails, the mode switching is started to switch to the off-grid operation mode; if the mode switching fails, a black start strategy is entered. In the black start strategy, the energy storage inverter of the energy storage system is used to establish the bus voltage in the grid, start the new energy power generation system, close the load switch, and enter the off-grid operation mode, which can effectively deal with the situation where the switching failure from the grid-connected operation mode to the off-grid operation mode occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] FIG1 (a) is a schematic flow chart of a method for coordinated control of a multi-converter system of a new energy station in one embodiment;

[0033] FIG1( b ) is a schematic diagram of a process of switching from a grid-connected operation mode to an off-grid operation mode in one embodiment;

[0034] Figure 2 A schematic diagram of a black start strategy in one embodiment;

[0035] Figure 3 A schematic diagram of a process of switching from an off-grid operation mode to a grid-connected operation mode in one embodiment;

[0036] Figure 4 A schematic diagram of a process for smoothing new energy fluctuations in one embodiment;

[0037] Figure 5 It is a schematic diagram of a process in an off-grid operation mode in an embodiment;

[0038] Figure 6 It is a structural block diagram of a cooperative control device for a multi-converter system of a new energy station in one embodiment;

[0039] Figure 7 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0041] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0042] The collaborative control method of a multi-converter system for a new energy station provided in the present application is introduced below in conjunction with FIG. 1( a ) and FIG. 1( b ).

[0043] Step S101, in the grid-connected operation mode, detecting whether a grid failure occurs through the energy storage converter of the energy storage system.

[0044] The new energy power generation system may include a wind power system. The energy storage system may operate in a grid-connected mode and an off-grid mode. When the energy storage system operates in a grid-connected mode, the energy storage converter (PCS, Power Conversion System) in the energy storage system can monitor whether the grid fails; if the grid does not fail, it remains in the grid-connected mode.

[0045] Step S102: if a power grid failure occurs, start mode switching to switch to an off-grid operation mode.

[0046] When the energy storage converter detects a grid collapse accident, the energy storage system can be disconnected from the grid and initiate mode switching to switch from the grid-connected operation mode to the off-grid operation mode.

[0047] Step S103, if the mode switching fails, enter the black start strategy, in which the energy storage converter of the energy storage system is used to establish the bus voltage in the grid, start the new energy power generation system, close the load switch, and enter the off-grid operation mode.

[0048] If the switch fails and the renewable energy power generation system is paralyzed, the black start strategy can be used to restore the normal operation of the renewable energy power generation system. The black start strategy is a method of quickly restoring power supply after a complete power outage in the renewable energy power generation system. It mainly establishes the bus voltage within the grid through the energy storage inverter of the energy storage system, gradually starts the equipment in the renewable energy power generation system, and finally gradually closes the load switch to restore the power supply of the renewable energy power generation system and enter the off-grid operation mode.

[0049] Furthermore, the black start strategy includes Figure 2 The process shown:

[0050] (1) Grid failure, failure to switch from grid-connected operation mode to off-grid operation mode, and the black start strategy is initiated;

[0051] (2) Read important load classification, equipment power, energy storage SOC, power and other information in the new energy power generation system, calculate the operating time, and calculate whether to cut off general loads;

[0052] (3) Start the energy storage converter of the energy storage system to establish the bus voltage within the grid;

[0053] (4) Gradually start up the equipment in the new energy power generation system and gradually increase the power output of the new energy power generation system;

[0054] (5) Gradually close the load switch;

[0055] (6) Black start is completed and the system enters off-grid operation mode.

[0056] In the above-mentioned collaborative control method of the multi-converter system of the new energy station, in the grid-connected operation mode, the energy storage inverter of the energy storage system is used to detect whether a fault occurs in the power grid; if a fault occurs in the power grid, the mode switching is initiated to switch to the off-grid operation mode; if the mode switching fails, a black start strategy is entered. In the black start strategy, the energy storage inverter of the energy storage system is used to establish the bus voltage within the grid, start the new energy power generation system, close the load switch, and enter the off-grid operation mode, which can effectively deal with the situation where the switching from the grid-connected operation mode to the off-grid operation mode fails.

[0057] In one of the embodiments, if a power grid failure occurs, the method provided in the present application further includes: triggering the energy storage converter to disconnect the grid connection point switch, and triggering the energy storage converter to switch from a current source mode to a voltage source mode.

[0058] In one of the embodiments, after entering the off-grid operation mode, the method provided in the present application also includes: when the power grid recovery is detected, determining whether the power grid recovery lasts for a set time; if so, initiating mode switching to switch to the grid-connected operation mode.

[0059] The set duration can be set according to actual conditions and can be set to 20 seconds.

[0060] Reference Figure 3 After entering the off-grid operation mode, PCS can detect whether the power grid has been restored. If so, it determines whether the power grid recovery lasts for 20 seconds or more. If so, it can start the mode switch. If the switch is successful, it enters the grid-connected operation mode. If the switch fails, it can report a fault.

[0061] In one of the embodiments, if the power grid recovery lasts for a set period of time, the method provided in the present application also includes: triggering the energy storage inverter to close the grid connection point switch.

[0062] In one of the embodiments, in the grid-connected operation mode, the following control modes are coordinated: transient stability control, fault ride-through compensation capability, system flow optimization, system peak regulation, smoothing of output fluctuations, and coordination between control cycles and priorities of various modes to ensure that corresponding functions are set in different areas, ultimately achieving multifunctional applications of new energy power generation systems and energy storage systems.

[0063] Among them, the strategy for smoothing new energy fluctuations adopted in the smooth output fluctuation mode may include the following steps: taking the output power of the new energy power generation system as the control object, and using the energy storage system to smooth the output power so that the output power fluctuates within the set range.

[0064] Furthermore, taking the output power of the renewable energy power generation system as the control object, the energy storage system is used to smooth the output power so that the output power fluctuates within a set range. Specifically, the following may be included: obtaining the average output power of the renewable energy power generation system in a historical period; taking the average output power as the control target, and obtaining a power control instruction according to the difference between the output power of the renewable energy power generation system and the average output power; and smoothing the output power according to the power control instruction and the energy storage system so that the output power fluctuates within a set range.

[0065] Reference Figure 4 , the real-time output power P of the new energy power generation system can be read, the average output power Pn of the new energy power generation system in the previous n minutes can be calculated, and the difference ΔP between the real-time output power P and the average output power Pn can be calculated; it is determined whether the SOC of the new energy power generation system is less than 80%, and if so, the set output power Pset is subtracted from ΔP, and a power control instruction is formed based on ΔP minus the output power Pset;

[0066] If the SOC (State-of-Charge) of the new energy power generation system is not less than 80%, it is determined whether the SOC of the new energy power generation system is greater than 90%. If so, the set output power Pset is added to ΔP, and a power control instruction is formed based on ΔP with the output power Pset added. If the SOC of the new energy power generation system is not greater than 90%, a power control instruction is formed based on ΔP.

[0067] The power control command is sent to the PCS of the energy storage system to smooth the output power of the renewable energy power generation system so that the output power fluctuates within the set range.

[0068] During the off-grid operation mode, the control principle is mainly to make full use of the output power of photovoltaic, wind power and other new energy power generation systems to extend the off-grid operation time. The specific processing process includes Figure 5 Steps shown.

[0069] The PCS of the energy storage system works in voltage source mode and can automatically maintain the stability of the three-phase output voltage frequency and amplitude without any control instructions from the energy management system.

[0070] Under normal circumstances, photovoltaic, wind power and other new energy power generation systems adopt MPPT control (MPPT's Chinese name is: Maximum Power Point Tracking, and its full English name is Maximum Power Point Tracking) to maximize output power; when the load is light, the output power of photovoltaic, wind power and other new energy power generation systems will be greater than the load power. At this time, the DC / DC module will work in the charging condition to charge the battery; when all batteries are about to be fully charged, the monitoring and dispatching system will issue an instruction to limit the output power of wind power, photovoltaic and other new energy power generation systems according to the load power. At this time, only two DC / DC modules are retained to complete the suppression control of power fluctuations; when limiting the output power of wind power, photovoltaic and other new energy power generation systems, the energy management system first removes wind turbines in groups and adjusts the power of photovoltaics at the same time; when all wind turbines are removed, measures are taken to limit the output power of photovoltaics to maintain power balance.

[0071] According to the power generation capacity of new energy power generation systems such as photovoltaic and wind power, the charge status of the battery, the capacity classification of the load, and the expected power supply time, the initial number of loads that can be put into operation (for example, primary and secondary) is determined; if only the primary load is put into operation, and the primary load is actually lighter, the secondary load can be added if the given power supply requirements are met; when both levels of loads are put into operation, if the power generation capacity of new energy power generation systems such as photovoltaic and wind power is reduced, and the energy of the battery is insufficient to support all loads according to the power supply time requirements, the capacity that the battery should retain is calculated according to the power supply requirements of the primary load, and when the battery capacity is reduced below this capacity, the secondary load is cut off; when the battery capacity is consumed to the minimum capacity limit value, all loads are cut off; keep the new energy power generation systems such as photovoltaic and wind power in a connected state to charge the battery.

[0072] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0073] Based on the same inventive concept, the embodiment of the present application also provides a new energy station multi-converter system collaborative control device for implementing the new energy station multi-converter system collaborative control method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of one or more new energy station multi-converter system collaborative control devices provided below can refer to the limitations of the new energy station multi-converter system collaborative control method above, and will not be repeated here.

[0074] In one embodiment, Figure 6 As shown, a new energy station multi-converter system coordinated control device is provided, comprising:

[0075] The power grid detection module 601 is used to detect whether a power grid fault occurs through the energy storage converter of the energy storage system in the grid-connected operation mode;

[0076] A mode switching module 602 is used to start mode switching to switch to an off-grid operation mode if a failure occurs in the power grid;

[0077] The black start module 603 is used to enter the black start strategy if the mode switching fails. In the black start strategy, the bus voltage in the grid is established through the energy storage converter of the energy storage system, the new energy power generation system is started, the load switch is closed, and the off-grid operation mode is entered.

[0078] In one embodiment, if the power grid fails, the device further includes: an off-grid mode processing module, which is used to trigger the energy storage converter to disconnect the grid connection point switch and trigger the energy storage converter to switch from the current source mode to the voltage source mode.

[0079] In one embodiment, after entering the off-grid operation mode, the device also includes: a recovery detection module, which is used to determine whether the power grid recovery lasts for a set time when detecting that the power grid has recovered; if so, initiating mode switching to switch to the grid-connected operation mode.

[0080] In one embodiment, if the power grid recovery lasts for a set time, the device further includes: a grid-connected mode processing module, configured to trigger the energy storage converter to close a grid-connected point switch.

[0081] In one embodiment, in the grid-connected operation mode, the device also includes: a new energy fluctuation smoothing processing module, which is used to take the output power of the new energy power generation system as the control object, and use the energy storage system to smooth the output power so that the output power fluctuates within a set range.

[0082] In one embodiment, the module for smoothing the fluctuations of new energy is also used to: obtain the average output power of the new energy power generation system in a historical period; use the average output power as a control target, and obtain a power control instruction according to the difference between the output power of the new energy power generation system and the average output power; and smooth the output power according to the power control instruction and the energy storage system so that the output power fluctuates within a set range.

[0083] Each module in the above-mentioned new energy station multi-converter system collaborative control device can be fully or partially implemented by software, hardware and their combination. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0084] In an exemplary embodiment, a computer device is provided, the internal structure of which can be shown as follows: Figure 7As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data involved in the above method. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for collaborative control of a multi-converter system of a new energy station is implemented.

[0085] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0086] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the above-mentioned various method embodiments when executing the computer program.

[0087] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0088] In one embodiment, a computer program product is provided, on which a computer program is stored, and the computer program is used by a processor to execute the steps in the above-mentioned various method embodiments.

[0089] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0090] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0091] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0092] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for coordinated control of a multi-converter system in a new energy station, characterized in that: The method comprises: In the grid-connected operation mode, the energy storage converter of the energy storage system detects whether the grid fails; If the power grid fails, a mode switch is initiated to switch to an off-grid operation mode; If the mode switching fails, a black start strategy is entered, in which the bus voltage in the grid is established through the energy storage converter of the energy storage system, the new energy power generation system is started, the load switch is closed, and the off-grid operation mode is entered.

2. The method according to claim 1, characterized in that If the power grid fails, the method further includes: The energy storage converter is triggered to disconnect the grid-connected point switch, and the energy storage converter is triggered to switch from the current source mode to the voltage source mode.

3. The method according to claim 1, characterized in that After entering the off-grid operation mode, the method further includes: When the power grid is detected to be restored, determining whether the power grid restoration lasts for a set time period; If so, the mode switching is initiated to switch to the grid-connected operation mode.

4. The method according to claim 3, characterized in that If the power grid recovery lasts for a set period of time, the method further includes: The energy storage converter is triggered to close the grid-connected point switch.

5. The method according to claim 3, characterized in that: In the grid-connected operation mode, the method further includes: The output power of the new energy power generation system is taken as the control object, and the output power is smoothed by using the energy storage system so that the output power fluctuates within a set range.

6. The method according to claim 5, characterized in that Taking the output power of the new energy power generation system as the control object, the output power is smoothed by using the energy storage system so that the output power fluctuates within a set range, including: Obtaining the average output power of the new energy power generation system in a historical period; Taking the average output power as a control target, and obtaining a power control instruction according to a difference between the output power of the new energy power generation system and the average output power; According to the power control instruction and the energy storage system, the output power is smoothed so that the output power fluctuates within a set range.

7. A new energy station multi-converter system coordinated control device, characterized in that: The device comprises: A power grid detection module is used to detect whether a power grid fault occurs through the energy storage converter of the energy storage system in the grid-connected operation mode; A mode switching module, used to initiate mode switching to switch to an off-grid operation mode if a failure occurs in the power grid; The black start module is used to enter the black start strategy if the mode switching fails. In the black start strategy, the bus voltage in the grid is established through the energy storage converter of the energy storage system, the new energy power generation system is started, the load switch is closed, and the off-grid operation mode is entered.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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