Energy storage system fast frequency regulation energy management method, system, device and storage medium

Abstract

The present application belongs to the technical field of electric power energy storage, and discloses an energy storage system fast frequency regulation energy management method, system, device and storage medium, obtains a frequency variation of a grid-connected point of an energy storage system, calculates energy storage unit charging and discharging requirements, calculates charging and discharging weights of each energy storage unit according to a state of charge of the energy storage unit and an in-cabin temperature, calculates a power distribution instruction value based on the energy storage unit charging and discharging requirements and the charging and discharging weights of each energy storage unit, and transmits the power distribution instruction value to an on-site control system or an energy storage converter of the energy storage unit. The present application fully considers the inconsistency of the SOC of each energy storage unit and the in-cabin temperature, can tilt the power distribution instruction to the energy storage unit with high SOC and low in-cabin temperature during discharging, and can tilt the power instruction to the energy storage unit with low SOC and low in-cabin temperature during charging, so as to realize optimal energy management effect, improve the energy utilization efficiency of the energy storage system, and prolong the service life of the energy storage battery pack.

Description

Technical Field

[0001] This invention belongs to the field of power energy storage technology, and particularly relates to a method, system, device and storage medium for fast frequency regulation energy management of energy storage systems. Background Technology

[0002] With the continuous growth of new energy installed capacity, in order to promote the consumption of new energy, the operating ratio of conventional thermal power units with traditional rotational inertia has gradually decreased, resulting in significant changes in the power supply structure. Traditional frequency regulation resources are becoming increasingly insufficient. Furthermore, the interfaces between wind power, photovoltaic power and the power system are power electronic devices, which can provide very limited inertial support. When the power system encounters power disturbances, it is difficult to quickly provide power support, and the amplitude and frequency of frequency fluctuations have increased accordingly, making system frequency regulation increasingly difficult.

[0003] Energy storage systems offer fast response times and flexible charging and discharging capabilities, making them ideal for improving the rapid frequency regulation (RFG) capabilities of power systems. In RPG applications, an energy storage system consists of several energy storage units as the smallest control objects, along with a coordinating controller that issues power control commands to these units. Each energy storage unit comprises an energy storage converter and a battery. In the initial stages of a significant disturbance, the coordinating controller within the energy storage system monitors frequency changes at the grid connection point and can issue charging and discharging commands to each energy storage unit using droop control or virtual inertia control strategies. This rapidly provides active power support, reduces the system frequency sag rate, and minimizes the maximum system frequency deviation, thereby improving the frequency stability of the power system. However, in RPG applications requiring millisecond-level frequency regulation, the need to provide substantial active power within a short timeframe can impact the operation of energy storage converters and batteries, affecting their lifespan and potentially causing fires or other safety incidents. Therefore, it is crucial to fully consider the operating conditions of the energy storage devices within different units and rationally allocate power commands among them to minimize the impact of RPG on the energy storage equipment. Summary of the Invention

[0004] To overcome the problems in the prior art, the purpose of this invention is to propose a method, system, device and storage medium for fast frequency regulation energy management of energy storage systems. This method can rationally allocate power commands between energy storage units according to the working status of the energy storage converter and energy storage battery, reduce the impact of fast frequency regulation on energy storage equipment, and improve the operational safety and economy of the energy storage system.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A rapid frequency regulation energy management method for energy storage systems includes the following steps: Obtain the frequency variation at the grid connection point of the energy storage system; Calculate the charging and discharging requirements of the energy storage unit based on the frequency variation at the grid connection point; Calculate the charge and discharge weights of each energy storage unit based on the state of charge of the energy storage unit and the temperature inside the chamber; The power allocation instruction value is calculated based on the charging and discharging requirements of the energy storage units and the charging and discharging weights of each energy storage unit. The power distribution command value is transmitted to the local control system or energy storage converter of the energy storage unit to realize the energy management of the energy storage unit of the energy storage system.

[0006] Furthermore, the charging and discharging requirements of energy storage units Calculated using the following formula:

[0007] in, The change in frequency The droop coefficient is... This is the frequency dead zone.

[0008] Furthermore, the droop coefficient takes the following values:

[0009] in, , These are the discharge and charging droop coefficients, respectively.

[0010] Furthermore, the charge / discharge weights of each energy storage unit include the first... i The discharge weight of the first energy storage unit and the first i The charging weight of each energy storage unit; No. i Discharge weight of each energy storage unit Calculated using the following formula:

[0011] in, For energy storage units SOC coefficient, Temperature weighting coefficient for energy storage unit equipment; For the first i The state of charge of each energy storage unit The average state of charge of all grid-connected energy storage units; For the first i The internal temperature of each energy storage unit The average cabin temperature of all grid-connected energy storage units.

[0012] Furthermore, the first i Charging weight of each energy storage unit Calculated using the following formula: .

[0013] Furthermore, the power allocation command value is determined through the following process: 1) When the grid connection frequency is lower than the grid operating frequency, the power demand... When it is positive, the first i Power allocation command value for each energy storage unit for:

[0014]

[0015] In the formula, i is the energy storage unit number, and n is the number of energy storage units. For the first i Discharge executable states of each energy storage unit; 2) When the grid connection frequency is higher than or equal to the grid operating frequency, the power demand... When it is negative, the first i Power allocation command value for each energy storage unit for:

[0016]

[0017] In the formula, For the first i The charging readiness status of each energy storage unit.

[0018] Furthermore, the first i The discharge executable state of an energy storage unit is determined through the following process: when the energy storage unit is in grid-connected operation and the state of charge of the energy storage unit is greater than the minimum allowable value of the state of charge, the energy storage unit is in the discharge executable state. No. i The charging executable state of an energy storage unit is determined through the following process: when the energy storage unit is in grid-connected operation and the state of charge of the energy storage unit is less than the maximum allowable value of the state of charge, the energy storage unit is in the charging executable state.

[0019] A fast frequency regulation energy management system for energy storage systems, comprising: The grid connection point frequency change acquisition module is used to acquire the frequency change of the grid connection point of the energy storage system. The energy storage unit charging and discharging demand calculation module is used to calculate the energy storage unit charging and discharging demand based on the frequency change at the grid connection point. The charge / discharge weight calculation module for each energy storage unit is used to calculate the charge / discharge weight of each energy storage unit based on the state of charge of the energy storage unit and the temperature inside the chamber. The power allocation instruction value calculation module is used to calculate the power allocation instruction value based on the charging and discharging requirements of the energy storage units and the charging and discharging weights of each energy storage unit. The transmission module is used to transmit power distribution command values ​​to the local control system or energy storage converter of the energy storage unit, so as to realize energy management of the energy storage unit of the energy storage system.

[0020] A computer device includes a memory and a processor, the memory storing a computer program that can run on the processor, the computer program being executed by the processor to implement the steps of the fast frequency regulation energy management method for an energy storage system as described above.

[0021] A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, which, when executed by a processor, causes the processor to perform the steps of the fast frequency modulation energy management method for an energy storage system as described above.

[0022] Compared with the prior art, the present invention has the following advantages: This invention provides an energy management method that can rationally allocate power commands among energy storage units based on the operating status of the energy storage converter and energy storage battery during rapid frequency regulation. This method fully considers the inconsistency of the State of Charge (SOC) and cabin temperature of each energy storage unit. After obtaining the power allocation command value, the power allocation command value is transmitted to the local control system or energy storage converter of the energy storage unit. During discharge, the power allocation command can be tilted towards energy storage units with high SOC and low cabin temperature, while during charging, the power command can be tilted towards energy storage units with low SOC and low cabin temperature, thereby achieving optimal energy management effect, improving the energy utilization efficiency of the energy storage system, extending the life of the energy storage battery pack, and reducing the probability of the whole station's full power response capability being affected by some energy storage units reaching the upper and lower limits of SOC too early. Attached Figure Description

[0023] Figure 1 Flowchart of a rapid frequency modulation energy management method for multiple energy storage units; Figure 2 This is a block diagram of a multi-energy storage unit fast frequency regulation energy management system. Detailed Implementation

[0024] 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 embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0026] This invention can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, elements, data structures, etc., that perform a specific task or implement a specific abstract data type. This invention can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0027] In this invention, terms such as "module," "device," and "system" refer to relevant entities applied to a computer, such as hardware, combinations of hardware and software, software, or software in execution. More specifically, for example, an element can be, but is not limited to, a process running on a processor, a processor, an object, an executable element, an execution thread, a program, and / or a computer. Furthermore, an application program or script running on a server, and the server itself, can also be an element. One or more elements may be in an execution process and / or thread, and elements may be localized on a single computer and / or distributed across two or more computers, and may be run on various computer-readable media. Elements can also communicate via local and / or remote processes based on signals having one or more data packets, for example, signals from data interacting with another element in a local system, a distributed system, and / or interacting with other systems via signals over a network of the Internet.

[0028] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising" or "including" include not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1 The present invention provides a method for fast frequency regulation energy management of a multi-energy storage unit energy storage system, comprising the following steps: Step S1: Calculate the charging and discharging requirements of the energy storage unit based on the frequency changes monitored at the grid connection point of the energy storage system. The frequency stability control strategy of the energy storage system adopts droop control, which is based on the absolute value of the frequency change at the grid connection point. Exceeding the frequency dead zone At that time, the charging and discharging power demand of the energy storage system Equal to the change in frequency With droop coefficient The product of.

[0030]

[0031]

[0032] in, , These are the discharge and charging droop coefficients, respectively.

[0033] Step S2, determine the executable state of the energy storage unit: 1) When the energy storage unit is in grid-connected operation and the energy storage unit is in a state of charge... Greater than the minimum allowable value of state of charge At this time, the energy storage unit is in a discharge-ready state; 2) When the energy storage unit is in grid-connected operation and the energy storage unit's state of charge... Less than the maximum permissible value of state of charge At that time, the energy storage unit is in a charging-ready state; 3) When the energy storage unit is in other states, the energy storage unit is in an unexecutable state.

[0034] Step S3: Based on the state of charge of the energy storage unit and the temperature inside the chamber, calculate the charge and discharge weights of each energy storage unit using an exponential function. 1) Calculate the first according to the following formula i Discharge weight of each energy storage unit :

[0035] in, For energy storage units SOC coefficient, Temperature weighting coefficient for energy storage unit equipment; For the first i The state of charge of each energy storage unit The average state of charge of all grid-connected energy storage units; For the first i The internal temperature of each energy storage unit The average cabin temperature of all grid-connected energy storage units.

[0036] 2) Calculate the first according to the following formula i Charging weight of each energy storage unit :

[0037] Step S4: Calculate the power allocation command value based on the charging and discharging weights of each energy storage unit.

[0038] 1) When the grid connection frequency is lower than the grid operating frequency, the energy storage system needs to discharge, resulting in power demand. When it is positive, the first i Power allocation command value for each energy storage unit for:

[0039]

[0040] In the formula, i is the energy storage unit number, and n is the number of energy storage units. For the first i Dischargeable states of each energy storage unit.

[0041] 2) When the grid connection frequency is higher than or equal to the grid operating frequency, the energy storage system needs to be charged, and the power demand is... When it is negative, the first i Power allocation command value for each energy storage unit for:

[0042]

[0043] In the formula, For the first i The charging readiness status of each energy storage unit.

[0044] Step S5: Assign power distribution command values ​​to each energy storage unit By issuing commands to the local control system or PCS (Power Conversion System) of the energy storage unit, energy management optimization of the energy storage unit can be achieved while the energy storage system responds quickly to frequencies.

[0045] The following are embodiments of the apparatus of the present invention, which can be used to execute embodiments of the method of the present invention. Regarding the apparatus embodiments... For details not disclosed herein, please refer to the embodiments of the method of this invention.

[0046] See Figure 2 In another embodiment of the present invention, a fast frequency regulation energy management system for energy storage system is provided, which can be used to implement the above-mentioned fast frequency regulation energy management method for energy storage system. The system specifically includes a grid connection point frequency change acquisition module, an energy storage unit charging and discharging demand calculation module, a charging and discharging weight calculation module for each energy storage unit, a power allocation command value calculation module, and a transmission module. Among them, the grid connection point frequency change acquisition module is used to acquire the frequency change of the grid connection point of the energy storage system; The energy storage unit charging and discharging demand calculation module is used to calculate the energy storage unit charging and discharging demand based on the frequency change at the grid connection point. The charge / discharge weight calculation module for each energy storage unit is used to calculate the charge / discharge weight of each energy storage unit based on the state of charge of the energy storage unit and the temperature inside the chamber. The power allocation instruction value calculation module is used to calculate the power allocation instruction value based on the charging and discharging requirements of the energy storage units and the charging and discharging weights of each energy storage unit. The transmission module is used to transmit power distribution command values ​​to the local control system or energy storage converter of the energy storage unit, so as to realize energy management of the energy storage unit of the energy storage system.

[0047] All relevant content of each step involved in the aforementioned embodiments of the fast frequency regulation energy management method for energy storage systems can be referenced from the functional description of the corresponding functional module of the fast frequency regulation energy management system for energy storage systems in the embodiments of the present invention, and will not be repeated here.

[0048] The module division in this embodiment of the invention is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the invention can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0049] In another embodiment of the present invention, a computer device is provided, comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes 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 (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to achieve a corresponding method flow or corresponding function. The processor described in this embodiment of the present invention can be used for the operation of a fast frequency modulation energy management method in an energy storage system.

[0050] In another embodiment of the present invention, a storage medium is provided, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). 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 storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the fast frequency modulation energy management method for energy storage systems in the above embodiments.

[0051] The following is a specific example: A 3MW / 3MWh energy storage system comprises three energy storage units, designated as energy storage unit 1, 2, and 3, each with a capacity of 1MW / 1MWh. Assume the energy storage coordinator detects a drop in the grid connection frequency to 49Hz, and a droop factor... =2, Based on step 1, calculate the charging and discharging power requirements of the energy storage system. =2MW.

[0052] The status parameters of the three energy storage units are collected as shown in the table below. According to step 2, it is determined that all three energy storage units are in a discharge-ready state.

[0053]

[0054] According to step 3, the charge / discharge weights of each energy storage unit are calculated based on the state of charge of the energy storage unit and the internal temperature of the compartment. SOC coefficient Take 15 as the temperature weighting coefficient for energy storage unit equipment. We set the value to 0.2 and then calculate the power allocation coefficient and power allocation command value according to step 4. The calculation results are shown in the table below.

[0055]

[0056] As can be seen from the results in the table above, during the discharge process of the energy storage system, energy storage unit 1, which has a high SOC and low internal temperature, received the most power allocation, while energy storage unit 2, which has a high SOC and high internal temperature, received slightly less power allocation, reducing the risk of excessively rapid temperature rise. Energy storage unit 3, which has a low SOC, received the least power allocation, reducing the probability that the energy storage unit will reach the lower limit of SOC too early and thus affect the full power response capability of the entire station.

[0057] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0058] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0059] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0060] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for rapid frequency regulation energy management of an energy storage system, characterized in that, Includes the following steps: Obtain the frequency variation at the grid connection point of the energy storage system; Calculate the charging and discharging requirements of the energy storage unit based on the frequency variation at the grid connection point; Calculate the charge and discharge weights of each energy storage unit based on the state of charge of the energy storage unit and the temperature inside the chamber; The power allocation command value is calculated based on the charging and discharging requirements of the energy storage units and the charging and discharging weights of each energy storage unit. The power distribution command value is transmitted to the local control system or energy storage converter of the energy storage unit to realize energy management of the energy storage unit of the energy storage system. The charge / discharge weights of each energy storage unit include the first i The discharge weight of the first energy storage unit and the first i The charging weight of each energy storage unit; No. i Discharge weight of each energy storage unit Calculated using the following formula: in, For energy storage units SOC coefficient, Temperature weighting coefficient for energy storage unit equipment; For the first i The state of charge of each energy storage unit The average state of charge of all grid-connected energy storage units; For the first i The internal temperature of each energy storage unit The average cabin temperature of all grid-connected energy storage units; No. i Charging weight of each energy storage unit Calculated using the following formula: The power allocation command value is determined through the following process: 1) When the grid connection frequency is lower than the grid operating frequency, the power demand... When it is positive, the first i Power allocation command value for each energy storage unit for: In the formula, i is the energy storage unit number, and n is the number of energy storage units. For the first i Discharge executable states of each energy storage unit; 2) When the grid connection frequency is higher than or equal to the grid operating frequency, the power demand... When it is negative, the first i Power allocation command value for each energy storage unit for: In the formula, For the first i The charging readiness status of each energy storage unit.

2. The fast frequency regulation energy management method for energy storage systems according to claim 1, characterized in that, Energy storage unit charging and discharging requirements Calculated using the following formula: in, The change in frequency The droop coefficient is... This is the frequency dead zone.

3. The fast frequency regulation energy management method for energy storage systems according to claim 2, characterized in that, The droop coefficient values ​​are as follows: in, , These are the discharge and charging droop coefficients, respectively.

4. The fast frequency regulation energy management method for energy storage systems according to claim 1, characterized in that, No. i The discharge executable state of an energy storage unit is determined through the following process: when the energy storage unit is in grid-connected operation and the state of charge of the energy storage unit is greater than the minimum allowable value of the state of charge, the energy storage unit is in the discharge executable state. No. i The charging executable state of an energy storage unit is determined through the following process: when the energy storage unit is in grid-connected operation and the state of charge of the energy storage unit is less than the maximum allowable value of the state of charge, the energy storage unit is in the charging executable state.

5. A fast frequency regulation energy management system for an energy storage system, characterized in that, include: The grid connection point frequency change acquisition module is used to acquire the frequency change of the grid connection point of the energy storage system. The energy storage unit charging and discharging demand calculation module is used to calculate the energy storage unit charging and discharging demand based on the frequency change at the grid connection point. The charge / discharge weight calculation module for each energy storage unit is used to calculate the charge / discharge weight of each energy storage unit based on the state of charge of the energy storage unit and the temperature inside the chamber. The power allocation instruction value calculation module is used to calculate the power allocation instruction value based on the charging and discharging requirements of the energy storage units and the charging and discharging weights of each energy storage unit. The transmission module is used to transmit power distribution command values ​​to the local control system or energy storage converter of the energy storage unit to realize energy management of the energy storage unit of the energy storage system. The charge / discharge weights of each energy storage unit include the first i The discharge weight of the first energy storage unit and the first i The charging weight of each energy storage unit; No. i Discharge weight of each energy storage unit Calculated using the following formula: in, For energy storage units SOC coefficient, Temperature weighting coefficient for energy storage unit equipment; For the first i The state of charge of each energy storage unit The average state of charge of all grid-connected energy storage units; For the first i The internal temperature of each energy storage unit The average cabin temperature of all grid-connected energy storage units; No. i Charging weight of each energy storage unit Calculated using the following formula: The power allocation command value is determined through the following process: 1) When the grid connection frequency is lower than the grid operating frequency, the power demand... When it is positive, the first i Power allocation command value for each energy storage unit for: In the formula, i is the energy storage unit number, and n is the number of energy storage units. For the first i Discharge executable states of each energy storage unit; 2) When the grid connection frequency is higher than or equal to the grid operating frequency, the power demand... When it is negative, the first i Power allocation command value for each energy storage unit for: In the formula, For the first i The charging readiness status of each energy storage unit.

6. A computer device, characterized in that, The computer device includes a memory and a processor, the memory storing a computer program that can run on the processor, the computer program being executed by the processor to implement the steps of the fast frequency regulation energy management method for the energy storage system according to any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, causes the processor to perform the steps of the fast frequency modulation energy management method for an energy storage system as described in any one of claims 1 to 4.

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