Method, device and medium for cluster energy storage participating in emergency frequency control of power system

Abstract

The application discloses a kind of cluster energy storage participates in the emergency frequency control method, device and medium of power system.The method is by the first droop coefficient of cluster energy storage system in the power system and the second droop coefficient of synchronous machine is cooperated optimization and obtains first optimal droop coefficient and second optimal droop coefficient;The frequency deviation of power system and the SOC value of cluster energy storage system in the power system are monitored, when the frequency deviation is greater than first preset threshold and the SOC value is greater than second preset threshold, according to the first optimal droop coefficient, the cluster energy storage system is controlled and according to the second optimal droop coefficient, the droop control of synchronous machine in power system is carried out.The technical scheme of the present application improves the stability of power system emergency frequency control.

Description

Technical Field

[0001] This invention relates to the field of emergency frequency control technology for power systems, and in particular to a method, device, and storage medium for clustered energy storage to participate in emergency frequency control of power systems. Background Technology

[0002] With the continuous development and utilization of renewable energy and the implementation of various energy storage technologies, my country's power grid is showing a trend towards power electronics. Power electronic power systems face more complex stability control problems. Considering the frequency stability of the power system, due to the large influx of renewable energy generation, insufficient system inertia or insufficient frequency regulation reserves may lead to difficulties in meeting frequency regulation demands. Therefore, when the system experiences faults with potentially large power imbalances, conventional frequency control strategies are insufficient to guarantee system frequency stability, necessitating emergency frequency control strategies.

[0003] Traditional power system emergency frequency control strategies primarily involve emergency generator and load shedding operations, but these strategies can lead to significant economic losses. Considering the clustered development of energy storage systems, which offer rapid power adjustment capabilities, more economical and effective emergency frequency control can be designed to improve system frequency stability when clustered energy storage is involved. Existing methods for energy storage systems participating in grid frequency regulation are all geared towards conventional frequency regulation, such as primary and secondary regulation, and do not address emergency frequency control under emergency fault conditions.

[0004] The closest existing technology to this invention is the emergency frequency control method in an AC / DC hybrid system, which considers the Pf droop control of the DC transmission system and optimizes the selection of its droop coefficient. The specific steps of this method are as follows:

[0005] (1) Analyze the active power-frequency (Pf) droop characteristics of the DC transmission system through the static characteristic curve, and design a Pf droop control to be applied to the DC transmission system.

[0006] (2) A method for arranging droop control in a DC system is proposed, and the control is implemented based on dead zone setting so that it only operates when an emergency fault occurs;

[0007] (3) Considering the power regulation margin of the DC system, an optimization method for the droop coefficient is given to achieve a reasonable distribution of unbalanced power among multiple DC systems.

[0008] The existing emergency frequency control methods have the following drawbacks:

[0009] (1) The emergency frequency control strategy and method for cluster energy storage system are not considered. The existing emergency frequency control strategy for DC system is based on the Pf droop characteristic of DC system. If the method is extended to cluster energy storage system, the operating characteristics of cluster energy storage and the feasibility of deploying emergency frequency control in cluster energy storage must be considered.

[0010] (2) Existing methods only consider the power regulation margin when optimizing the droop coefficient. However, when considering clustered energy storage systems, it is necessary to consider not only the power regulation margin but also the SOC of the energy storage system. Therefore, according to actual engineering needs, multiple objectives need to be considered when optimizing the droop coefficient, and existing methods cannot meet this requirement. Summary of the Invention

[0011] This invention provides a method, device, and medium for clustered energy storage to participate in emergency frequency control of a power system. By controlling the coordinated droop of the clustered energy storage system and the synchronous machine in the power system during emergency faults according to the optimal droop coefficient, the stability of emergency frequency control of the power system is improved.

[0012] An embodiment of the present invention provides a method for clustered energy storage to participate in emergency frequency control of a power system, comprising the following steps:

[0013] The first optimal droop coefficient and the second optimal droop coefficient are obtained by co-optimizing the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizing machine in the power system.

[0014] The frequency deviation of the power system and the SOC value of the cluster energy storage system in the power system are monitored. When the frequency deviation is greater than a first preset threshold and the SOC value is greater than a second preset threshold, droop control is performed on the cluster energy storage system according to a first optimal droop coefficient and droop control is performed on the synchronous machine in the power system according to the second optimal droop coefficient.

[0015] Furthermore, droop control of the cluster energy storage system is performed based on the first optimal droop coefficient, including the following steps:

[0016] Based on the frequency of the grid connection point of the cluster energy storage system, the rated value of the grid connection point of the cluster energy storage system, the rated operating power of the cluster energy storage system, and the first optimal droop coefficient, the power command value of the cluster energy storage system is calculated, and the power command value is input to the energy storage converter.

[0017] The energy storage converter adjusts the power of the cluster energy storage system in response to an emergency fault based on the received power command value.

[0018] Furthermore, the first optimal droop coefficient and the second optimal droop coefficient of the cluster energy storage system and the synchronizing machine in the power system are jointly optimized to obtain the first optimal droop coefficient and the second optimal droop coefficient, including the following steps:

[0019] Based on the first droop coefficient of the energy storage cluster system and the second droop coefficient of the synchronizing machine, calculate the first power regulation of the energy storage cluster system and the second power regulation of the synchronizing machine, respectively.

[0020] The total cost function of the cluster energy storage system and the synchronous machine's coordinated droop control is established based on the first power adjustment amount, the second power adjustment amount, the first control objective, and the second control objective.

[0021] The total cost function is verified by performing optimal droop control based on the state equation of the power system, and the first optimal droop coefficient of the cluster energy storage system and the second optimal droop coefficient of the synchronizing machine are obtained based on the optimal droop control verification results and the total cost function.

[0022] Furthermore, the calculation formulas for the first optimal droop coefficient and the second optimal droop coefficient are as follows:

[0023]

[0024] In the formula, λ 1i and λ 2i λ is the weighting coefficient. 1i +λ 2i =1; Let be the second optimal droop coefficient for synchronizer i. Let be the first optimal droop coefficient for clustered energy storage system i. This represents the connection node of the clustered energy storage system. Represents a synchronous machine node, α i and β i These are the cost coefficients for the first control objective and the second control objective, respectively. For the power regulation margin of cluster energy storage system i, The SOC of clustered energy storage system i.

[0025] Furthermore, the state equation of the power system is:

[0026]

[0027]

[0028]

[0029]

[0030] In the formula, i and j are node numbers, and θ i and θ j These are the phase angles at node i and node j, respectively, ω i M is the frequency deviation relative to the rated frequency. i >0 is the inertial constant of synchronous machine i, P i For the power injection or demand at node i, P i E B is the rated output power of cluster energy storage system i. ij For the effective admittance of the line, V i and V j The preset voltage amplitude, This represents the connection node of the clustered energy storage system. Indicates a synchronous machine node. This indicates a passive load node.

[0031] Furthermore, the total cost equation for the cluster energy storage system and the synchronizer-coordinated droop control is as follows:

[0032]

[0033] In the formula, λ 1j and λ 2i λ is the weighting coefficient. 1i +λ 2i =1; This is the first power regulation value for the cluster energy storage system; This is the second power regulation value of the synchronous machine; Let be the first droop coefficient of synchronizer i. α is the second droop coefficient of clustered energy storage system i; i and β i These are the cost coefficients for the first control objective and the second control objective, respectively. For the power regulation margin of cluster energy storage system i, For the SOC of clustered energy storage system i, The control cost function of a synchronous machine is represented. This represents the control cost function of the clustered energy storage system in relation to the first control objective. This represents the control cost function related to the second control objective of the clustered energy storage system.

[0034] Furthermore, based on the frequency of the grid connection point of the cluster energy storage system, the rated value of the grid connection point of the cluster energy storage system, the rated operating power of the cluster energy storage system, and the first optimal droop coefficient, the power command value of the cluster energy storage system is calculated, specifically as follows:

[0035] According to the formula Calculate the power command value of the cluster energy storage system, where, P is the power command for the cluster energy storage system. E k represents the rated operating power of the cluster energy storage system. E ω is the first optimal droop coefficient. c The frequency of the grid connection point of the cluster energy storage system, ω cN This refers to the rated value of the grid connection point of the cluster energy storage system.

[0036] Another embodiment of the present invention provides a power dispatching device for incremental distribution networks, including an emergency frequency control module and an optimal droop coefficient acquisition module;

[0037] The emergency frequency control module is used to monitor the frequency deviation of the power system and the SOC value of the cluster energy storage system in the power system. When the frequency deviation is greater than a first preset threshold and the SOC value is greater than a second preset threshold, the module performs droop control on the cluster energy storage system according to a first optimal droop coefficient and performs droop control on the synchronizer in the power system according to the second optimal droop coefficient.

[0038] The optimal droop coefficient acquisition module is used to obtain the first optimal droop coefficient and the second optimal droop coefficient by co-optimizing the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizing machine in the power system.

[0039] Furthermore, in the emergency frequency control module, droop control of the cluster energy storage system is performed according to the first optimal droop coefficient, including the following steps:

[0040] Based on the frequency of the grid connection point of the cluster energy storage system, the rated value of the grid connection point of the cluster energy storage system, the rated operating power of the cluster energy storage system, and the first optimal droop coefficient, the power command value of the cluster energy storage system is calculated, and the power command value is input to the energy storage converter.

[0041] The energy storage converter adjusts the power of the cluster energy storage system in response to an emergency fault based on the received power command value.

[0042] Another embodiment of the present invention provides a readable storage medium, the readable storage medium including a stored computer program, which, when executed, controls the device where the readable storage medium is located to execute the emergency frequency control method for clustered energy storage participating in the power system as described in any one of the method embodiments of the present invention.

[0043] The embodiments of the present invention have the following beneficial effects:

[0044] This invention provides a method, device, and medium for clustered energy storage to participate in emergency frequency control of a power system. The method obtains a first optimal droop coefficient and a second optimal droop coefficient by co-optimizing a first droop coefficient of the clustered energy storage system and a second droop coefficient of the synchronizing machine in the power system. Then, it monitors the frequency deviation of the power system and the SOC value of the clustered energy storage system. When the frequency deviation exceeds a first preset threshold and the SOC value exceeds a second preset threshold, droop control is applied to the clustered energy storage system based on the first optimal droop coefficient and to the synchronizing machine in the power system based on the second optimal droop coefficient, thereby improving the stability of emergency frequency control in the power system. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating a method for clustered energy storage to participate in emergency frequency control of a power system, according to an embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of the structure of a clustered energy storage device participating in the emergency frequency control of a power system according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the process for droop control of the cluster energy storage system provided in an embodiment of the present invention. Detailed Implementation

[0048] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0049] like Figure 1 As shown, an embodiment of the present invention provides a method for clustered energy storage to participate in emergency frequency control of a power system, comprising the following steps:

[0050] Step S101: Obtain the first optimal droop coefficient and the second optimal droop coefficient by co-optimizing the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizing machine in the power system.

[0051] The purpose of coordinating the optimization of the first droop coefficient and the second droop coefficient is to achieve a reasonable distribution of unbalanced power among multiple cluster energy storage systems and multiple synchronous machines.

[0052] Step S102: Monitor the frequency deviation of the power system and the SOC value of the cluster energy storage system in the power system. When the frequency deviation is greater than a first preset threshold and the SOC value is greater than a second preset threshold, perform droop control on the cluster energy storage system according to the first optimal droop coefficient and perform droop control on the synchro in the power system according to the second optimal droop coefficient.

[0053] The droop control provided in this embodiment of the invention is to perform droop control on the clustered energy storage system according to the first optimal droop coefficient and to perform droop control on the synchronous machine in the power system according to the second optimal droop coefficient. The droop control mainly realizes the coordination between the droop control of the clustered energy storage system and the primary frequency regulation of the conventional synchronous machine. That is, the droop control of the clustered energy storage system only works in case of emergency failure, serving as a backup support for the primary frequency regulation of the synchronous machine.

[0054] As one embodiment, droop control of the cluster energy storage system based on a first optimal droop coefficient includes the following steps:

[0055] Based on the frequency of the grid connection point of the cluster energy storage system, the rated value of the grid connection point of the cluster energy storage system, the rated operating power of the cluster energy storage system, and the first optimal droop coefficient, the power command value of the cluster energy storage system is calculated, and the power command value is input to the energy storage converter; specifically, according to the formula... Calculate the power command value of the energy storage cluster, where, P is the power command for the cluster energy storage system. E k represents the rated operating power of the cluster energy storage system. E ω is the first optimal droop coefficient. c The frequency of the grid connection point of the cluster energy storage system, ω cN This refers to the rated value of the grid connection point of the cluster energy storage system.

[0056] like Figure 3 As shown, when an emergency frequency fault occurs in the power system, it causes a change in the power system frequency. At this time, the frequency signal at the grid connection point of the clustered energy storage can be measured through a phase-locked loop (PLL). frequency signal After filtering, it becomes ω c The frequency signal is input to the droop control loop; after the frequency signal is input to the droop control loop, it is processed by the droop control equation. Output the cluster energy storage system (corresponding to) Figure 2 Power command value of energy storage system in China The power command value of the cluster energy storage system The input is fed to the energy storage converter PCS, and the constant power control of the PCS enables the power regulation response of the cluster energy storage system in the event of an emergency fault.

[0057] The energy storage converter, based on the received power command value The power of the cluster energy storage system is adjusted in response to an emergency failure.

[0058] The principle underlying this invention is as follows: power control of a cluster energy storage system is primarily achieved through a power conversion system (PCS). Taking battery energy storage as an example, its PCS consists of a DC-AC bidirectional converter and a control unit, connected between the battery system and the power grid to achieve bidirectional energy conversion. The PCS enables the energy storage system to possess control modes such as constant power control, constant power factor control, and constant current control. Furthermore, according to the national standard "GB / T 36547-2018 Technical Specifications for Grid Connection of Electrochemical Energy Storage Systems," when the grid connection frequency is less than 49.5Hz, the energy storage should not be in a charging state; when the frequency is greater than 50.2Hz, the energy storage should not be in a discharging state. Based on the above-mentioned operating characteristics of energy storage systems, when the cluster energy storage system adopts constant power control mode, a Pf droop control for the cluster energy storage system can be designed. This can be achieved by constructing the correlation between the output power of the cluster energy storage system and the frequency of the energy storage grid connection point. That is, the frequency at the grid connection point is measured, and the command value is fed back to the power control unit of the cluster energy storage system through the droop control loop, thereby adjusting the output active power of the cluster energy storage system.

[0059] The state equations of the power system are obtained according to the following steps:

[0060] The power system can be represented as a diagram. Among the nodes This refers to the busbar in the power system, and the side... This refers to the transmission line in the power system. In power systems involving clustered energy storage, the bus can be classified into the following three categories:

[0061] Synchronous machine nodes, number n G ;

[0062] The cluster energy storage system has n connection nodes. E ;

[0063] There are n passive load nodes. P ;

[0064] And there are: n = n G +nE +n P .

[0065] Considering the rapid power adjustment characteristic of the clustered energy storage system, and ignoring the dynamics of the clustered energy storage system, only considering the synchronous machine in a second-order dynamic model, the state equation of the power system is:

[0066]

[0067] Where i and j are node numbers, θ i and θ j These are the phase angles at node i and node j, respectively, ω i M is the frequency deviation relative to the rated frequency (50Hz or 60Hz). i >0 is the inertial constant of synchronous machine i, P i For power injection (>0) or demand (<0) at node i, P i E The rated output power of cluster energy storage system i It is the effective admittance of line (i, j), where This is the actual admittance value, voltage amplitude V. i and V j Assume it is a constant. Synchronizer The second optimal droop coefficient. For clustered energy storage systems The first optimal droop coefficient.

[0068] As one embodiment, the first optimal droop coefficient and the second optimal droop coefficient of the clustered energy storage system in the power system are obtained by co-optimizing the first optimal droop coefficient and the second optimal droop coefficient, including the following steps:

[0069] Based on the first droop coefficient of the energy storage cluster system and the second droop coefficient of the synchronizing machine, calculate the first power regulation of the energy storage cluster system and the second power regulation of the synchronizing machine, respectively.

[0070] The total cost function of the cluster energy storage system and the synchronous machine's coordinated droop control is established based on the first power adjustment amount, the second power adjustment amount, the first control objective, and the second control objective.

[0071] The total cost function is verified by performing optimal droop control based on the state equation of the power system, and the first optimal droop coefficient of the cluster energy storage system and the second optimal droop coefficient of the synchronizing machine are obtained based on the optimal droop control verification results and the total cost function.

[0072] As one embodiment, the first optimal droop coefficient and the second optimal droop coefficient are obtained according to the following steps:

[0073] Calculate the first power regulation of the cluster energy storage system based on the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizer. and the second power regulation of the synchronous machine When determining the droop coefficient for collaborative optimization, a first control objective and a second control objective are established. The first control objective is to provide more power support to cluster energy storage systems with a larger power regulation margin (PRM), and the second control objective is to provide more power support to cluster energy storage systems with a larger State of Charge (SOC). The implicit meaning of the second control objective is to ensure that the SOC values ​​of all cluster energy storage systems are as consistent as possible after emergency frequency control ends. In practical engineering, both objectives sometimes need to be considered; therefore, a weighted approach can be used to comprehensively consider both control objectives.

[0074] Accordingly, the generalized control cost function of the synchronizer is:

[0075] The generalized control cost function of the clustered energy storage system has two parts, including the control cost function related to the first control objective:

[0076]

[0077] in, For power regulation margin:

[0078]

[0079] Among them, P i E The rated output power of cluster energy storage system i and These represent the upper and lower limits of the output power of cluster energy storage system i, respectively.

[0080] Control cost function related to the second control objective:

[0081]

[0082] in, The SOC of clustered energy storage system i.

[0083] According to formulas (2) and (4), the total cost function of the cluster energy storage system is:

[0084]

[0085] Where λ1i +λ 2i =1 represents a weight. When a weight is 0, the total cost function above only considers a single control objective. In this case, the optimization problem can be expressed as:

[0086]

[0087] Among them, the constraint condition of formula (6) is the power balance constraint.

[0088] The optimality of formula (6) is verified based on the state equation of the power system, including the following steps:

[0089] Transform the above formula (6) into a Lagrange dual function:

[0090]

[0091] Among them, P i For the power injection (>0) or demand (<0) at node i, λ is the dual variable. Then, the lower bound problem of the inner layer can be explicitly solved to obtain:

[0092]

[0093] Define vector Where λ i For the corresponding node i, therefore, when obtaining the optimal solution, we have

[0094] The dual problem of the original optimization problem is:

[0095]

[0096] The Lagrangian function of the dual problem of formula (9) is:

[0097]

[0098] in These are Lagrange multipliers. Furthermore, applying a partially primal-dual distributed algorithm to solve the dual problem yields the following form:

[0099]

[0100] Where τ i >0, γ ij >0 represents the calculation step size. If the variable λ... i and ν ij Replace with ω respectively i and P ij And set the step size τ i =1 / M i γ ij =Bij cos(θ i -θ j Integrating, we get P. ij =-B ij sin(θ i -θ j It can be seen that formula (10) is the same as the dynamic equation (1) of the power system.

[0101] Formula (6) calculates the first optimal droop coefficient and the second optimal droop coefficient by considering only a single control objective each time:

[0102]

[0103] Where i is the node number, α i and β i These are the cost coefficients for the first control objective and the second control objective, respectively. For the power regulation margin of cluster energy storage system i, Let i be the SOC of the cluster energy storage system. Since formula (10) is the same as the dynamic equation (1) of the power system, under the droop control and the setting of two optimal droop coefficients, the power system will reach the optimal along the trajectory of a partial original-dual distributed algorithm, ensuring the optimality of the first and second optimal droop coefficients. Therefore, the first and second optimal droop coefficients can be calculated according to formula (11).

[0104] This invention provides a method for optimizing the selection of control parameters for the reasonable allocation of unbalanced power among multiple clustered energy storage systems and multiple synchronous generating units. It can comprehensively consider the SOC and power regulation margin of the clustered energy storage system to achieve optimal control of the emergency frequency of the power system, thereby improving the stability of the emergency frequency control of the power system.

[0105] Based on the above embodiments, the present invention provides corresponding device embodiments, such as... Figure 2 As shown;

[0106] Another embodiment of the present invention provides an emergency frequency control device for clustered energy storage participating in a power system, including an emergency frequency control module and an optimal droop coefficient acquisition module;

[0107] The emergency frequency control module is used to monitor the frequency deviation of the power system and the SOC value of the cluster energy storage system in the power system. When the frequency deviation is greater than a first preset threshold and the SOC value is greater than a second preset threshold, the module performs droop control on the cluster energy storage system according to a first optimal droop coefficient and performs droop control on the synchronizer in the power system according to the second optimal droop coefficient.

[0108] The optimal droop coefficient acquisition module is used to obtain the first optimal droop coefficient and the second optimal droop coefficient by co-optimizing the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizing machine in the power system.

[0109] For ease of description and brevity, the embodiments of the present invention include all the implementation methods in the above embodiments of the method for clustered energy storage to participate in the emergency frequency control of the power system, and will not be repeated here.

[0110] Based on the above embodiments, the present invention provides a corresponding embodiment of a readable storage medium; another embodiment of the present invention provides a readable storage medium, the readable storage medium including a stored computer program, wherein when the computer program is executed, it controls the device where the readable storage medium is located to execute the emergency frequency control method for clustered energy storage participating in the power system as described in any one of the method embodiments of the present invention.

[0111] For example, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program in the terminal device.

[0112] The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0113] The processor can 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. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting all parts of the terminal device via various interfaces and lines.

[0114] The memory can be used to store the computer programs and / or modules. The processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory and by calling data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, phonebook, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0115] Wherein, if the modules / units integrated in the terminal device are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium (i.e., the aforementioned readable storage medium). Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, it can implement the steps of the various method embodiments described above. Wherein, the computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0116] It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0117] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

[0118] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

Claims

1. A method for clustered energy storage to participate in emergency frequency control of a power system, characterized in that, Includes the following steps: The first optimal droop coefficient and the second optimal droop coefficient are obtained by co-optimizing the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizer in the power system. This includes the following steps: calculating the first power regulation of the cluster energy storage system and the second power regulation of the synchronizer based on the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizer; establishing the total cost function for the coordinated droop control of the cluster energy storage system and the synchronizer based on the first power regulation, the second power regulation, the first control objective, and the second control objective; verifying the optimal droop control of the total cost function based on the state equation of the power system; and obtaining the first optimal droop coefficient of the cluster energy storage system and the second optimal droop coefficient of the synchronizer based on the optimal droop control verification result and the total cost function. The frequency deviation of the power system and the SOC value of the cluster energy storage system in the power system are monitored. When the frequency deviation is greater than a first preset threshold and the SOC value is greater than a second preset threshold, the cluster energy storage system is subjected to droop control according to a first optimal droop coefficient and the synchronous machine in the power system is subjected to droop control according to a second optimal droop coefficient. The calculation formulas for the first optimal droop coefficient and the second optimal droop coefficient are as follows: In the formula, λ 1i and λ 2i λ is the weighting coefficient. 1i +λ 2i =1; Let be the second optimal droop coefficient for synchronizer i. Let be the first optimal droop coefficient for clustered energy storage system i. This represents the connection node of the clustered energy storage system. Represents a synchronous machine node, α i and β i These are the cost coefficients for the first control objective and the second control objective, respectively. For the power regulation margin of cluster energy storage system i, The SOC of clustered energy storage system i.

2. The method for clustered energy storage to participate in emergency frequency control of the power system according to claim 1, characterized in that, The cluster energy storage system is subjected to droop control based on a first optimal droop coefficient, including the following steps: Based on the frequency of the grid connection point of the cluster energy storage system, the rated value of the grid connection point of the cluster energy storage system, the rated operating power of the cluster energy storage system, and the first optimal droop coefficient, the power command value of the cluster energy storage system is calculated, and the power command value is input to the energy storage converter. The energy storage converter adjusts the power of the cluster energy storage system in response to an emergency fault based on the received power command value.

3. The method for clustered energy storage to participate in emergency frequency control of the power system according to claim 1, characterized in that, The state equation of the power system is: In the formula, i and j are node numbers, and θ i and θ j These are the phase angles at node i and node j, respectively, ω i M is the frequency deviation relative to the rated frequency. i >0 is the inertial constant of synchronous machine i, P i For the power injection or demand at node i, P i E B is the rated output power of cluster energy storage system i. ij For the effective admittance of the line, V i and V j The preset voltage amplitude, This represents the connection node of the clustered energy storage system. Indicates a synchronous machine node. This indicates a passive load node.

4. The method for clustered energy storage to participate in emergency frequency control of the power system according to claim 3, characterized in that, The total cost equation for the clustered energy storage system and the synchronous machine's coordinated droop control is: In the formula, λ 1i and λ 2i λ is the weighting coefficient. 1i +λ 2i =1; α is the first power regulation parameter of the cluster energy storage system. i and β i These are the cost coefficients for the first control objective and the second control objective, respectively. For the power regulation margin of cluster energy storage system i, For the SOC of clustered energy storage system i, The control cost function of a synchronous machine is represented. This represents the control cost function of the clustered energy storage system in relation to the first control objective. This represents the control cost function related to the second control objective of the clustered energy storage system.

5. The method for clustered energy storage to participate in emergency frequency control of a power system according to any one of claims 1 to 4, characterized in that, Based on the frequency of the grid connection point of the cluster energy storage system, the rated value of the grid connection point of the cluster energy storage system, the rated operating power of the cluster energy storage system, and the first optimal droop coefficient, the power command value of the cluster energy storage system is calculated, specifically as follows: According to the formula Calculate the power command value of the cluster energy storage system, where, P is the power command for the cluster energy storage system. E k represents the rated operating power of the cluster energy storage system. E ω is the first optimal droop coefficient. c The frequency of the grid connection point of the cluster energy storage system, ω cN This refers to the rated value of the grid connection point of the cluster energy storage system.

6. A clustered energy storage device participating in emergency frequency control of a power system, characterized in that, Includes an emergency frequency control module and an optimal droop coefficient acquisition module; The emergency frequency control module is used to monitor the frequency deviation of the power system and the SOC value of the cluster energy storage system in the power system. When the frequency deviation is greater than a first preset threshold and the SOC value is greater than a second preset threshold, the module performs droop control on the cluster energy storage system according to a first optimal droop coefficient and performs droop control on the synchro in the power system according to a second optimal droop coefficient. The optimal droop coefficient acquisition module is used to obtain the first optimal droop coefficient and the second optimal droop coefficient by co-optimizing the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizer in the power system. The module includes the following steps: calculating the first power regulation of the cluster energy storage system and the second power regulation of the synchronizer based on the first droop coefficient of the cluster energy storage system and the second droop coefficient of the synchronizer; establishing the total cost function for the coordinated droop control of the cluster energy storage system and the synchronizer based on the first power regulation, the second power regulation, the first control objective, and the second control objective; verifying the optimal droop control of the total cost function based on the state equation of the power system; and obtaining the first optimal droop coefficient of the cluster energy storage system and the second optimal droop coefficient of the synchronizer based on the optimal droop control verification result and the total cost function. The calculation formulas for the first optimal droop coefficient and the second optimal droop coefficient are as follows: In the formula, λ 1i and λ 2i λ is the weighting coefficient. 1i +λ 2i =1; Let be the second optimal droop coefficient for synchronizer i. Let be the first optimal droop coefficient for clustered energy storage system i. This represents the connection node of the clustered energy storage system. Represents a synchronous machine node, α i and β i These are the cost coefficients for the first control objective and the second control objective, respectively. For the power regulation margin of cluster energy storage system i, The SOC of clustered energy storage system i.

7. The clustered energy storage device for participating in emergency frequency control of the power system according to claim 6, characterized in that, In the emergency frequency control module, droop control of the cluster energy storage system is performed according to the first optimal droop coefficient, including the following steps: Based on the frequency of the grid connection point of the cluster energy storage system, the rated value of the grid connection point of the cluster energy storage system, the rated operating power of the cluster energy storage system, and the first optimal droop coefficient, the power command value of the cluster energy storage system is calculated, and the power command value is input to the energy storage converter. The energy storage converter adjusts the power of the cluster energy storage system in response to an emergency fault based on the received power command value.

8. A readable storage medium, characterized in that, The readable storage medium includes a stored computer program, which, when executed, controls the device containing the readable storage medium to perform the emergency frequency control method for clustered energy storage participating in the power system as described in any one of claims 1 to 5.

Images