Power amplitude limiting setting method and system for improving transient stability of network construction device in current limiting

Abstract

The invention belongs to the technical field of inverter transient stability evaluation, and provides a power amplitude limiting setting method and system for improving the transient stability of a network construction device in current limiting. The method comprises the steps of triggering and controlling a grid-forming inverter to enter a current limiting mode when the grid-forming inverter grid-connected system has voltage drop at a power grid side, and limiting the increase of the power difference when the power difference exceeds the maximum value of the set power difference; the switching conditions are analyzed into corresponding power angle switching conditions; according to the power vacancy at the fault moment of the network-building type inverter, calculating the acceleration area of the network-building type inverter under the action of power amplitude limiting; on the basis of the relation between the fault clearing angle and the power angle switching condition of the network building type inverter, the deceleration area of the network building type inverter under the power amplitude limiting effect is obtained; and based on an equal area rule, solving a setting value range of a maximum value of a power difference value of power amplitude limiting under the condition of transient stability of the single-machine grid-connected system of the grid-forming inverter.

Description

Technical Field

[0001] The present invention belongs to the technical field of transient stability assessment of inverters, and in particular relates to a power limit setting method and system for improving the transient stability of a current-limiting network device. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] When grid voltage drops in a grid-connected inverter, the fault current can easily exceed the overcurrent threshold of the semiconductor components, requiring current limiting control to protect the grid-connected inverter. The prior art proposes the equal-area rule, which quantitatively analyzes the transient stability of a single-machine grid-connected system by analyzing the physical acceleration and deceleration of the rotor during transient processes. However, it does not consider the impact of the power limiting module and voltage loop dynamics on the grid-connected inverter mode switching. It is unable to quantify the impact of power limiting on the acceleration area when power limiting and priority current limiting work together, thereby reducing the accuracy of the grid-connected inverter's transient stability boundary and ultimately the transient stability of the grid-connected inverter, making it impossible to ensure the successful fault ride-through of new energy equipment. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a power limiting adjustment method and system for improving the temporary stability of a grid-forming device during current limiting. The method and system can fully consider the impact of the power limiting module and the voltage loop dynamics on the grid-forming mode switching, obtain the setting upper limit value of the power limiting module, improve the accuracy of the transient stability boundary of the grid-forming inverter, and ensure the transient stability of the grid-forming inverter and the successful fault ride-through of new energy equipment.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A first aspect of the present invention provides a power limit setting method for improving the temporary stability of a network-building device during current limiting.

[0006] In one or more embodiments, a power limit setting method for improving the temporary stability of a network-building device during current limiting is provided, comprising: A virtual synchronous machine is used to control the grid-connected inverter, and a voltage-current dual closed loop is used under normal operating conditions to achieve constant voltage mode control of the grid-connected inverter. When a voltage drop occurs on the grid side of the grid-connected system of the grid-connected inverter, the grid-connected inverter is triggered to enter the current limiting mode. When the power difference exceeds the set maximum power difference, the power difference is limited to increase. Calculate the switching conditions for the grid-type inverter to switch from constant voltage mode to current limiting mode and the switching conditions for the grid-type inverter to switch from current limiting mode to constant voltage mode, and resolve the switching conditions into corresponding power angle switching conditions; According to the power shortage of the grid-type inverter at the time of fault, the acceleration area of ​​the grid-type inverter under the action of power limitation is calculated; Based on the relationship between the fault clearing angle and power angle switching conditions of the grid-type inverter, the deceleration area of ​​the grid-type inverter under the action of power limitation is calculated; Based on the equal-area rule, the setting value range of the maximum power difference of the power limiter is obtained under the condition of transient stability of the grid-connected system with a single grid-connected inverter.

[0007] A second aspect of the present invention provides a power limiting setting system for improving the temporary stability of a network-building device during current limiting.

[0008] In one or more embodiments, a power limit setting system for improving temporary stability of a network device during current limiting includes: A constant voltage control module, which is used to control the grid-type inverter using a virtual synchronous machine and implement constant voltage mode control of the grid-type inverter using a voltage and current double closed loop under normal operating conditions; The current limiting control module is used to trigger the control grid-type inverter to enter the current limiting mode when the grid-type inverter grid-connected system has a voltage drop on the grid side, and limit the increase of the power difference when the power difference exceeds the set maximum power difference; A switching condition analysis module is used to calculate the switching conditions for the grid-type inverter to switch from constant voltage mode to current limiting mode and the switching conditions for the grid-type inverter to switch from current limiting mode to constant voltage mode, and analyze the switching conditions into corresponding power angle switching conditions; An acceleration area calculation module, which is used to calculate the acceleration area of ​​the grid-type inverter under the action of power limitation based on the power shortage of the grid-type inverter at the time of failure; A deceleration area calculation module is used to calculate the deceleration area of ​​the grid-type inverter under the action of power limiting based on the relationship between the fault clearing angle and the power angle switching condition of the grid-type inverter; The power difference upper limit setting module is used to obtain the setting value range of the maximum power difference of the power limit under the condition of transient stability of the grid-connected system of the grid-connected inverter single machine based on the equal area rule.

[0009] A third aspect of the present invention provides a computer-readable storage medium.

[0010] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the power limit adjustment method for temporarily stabilizing a network device during current limiting as described above.

[0011] A fourth aspect of the present invention provides an electronic device.

[0012] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the power limit adjustment method for temporarily stabilizing a network device during current limiting are implemented as described above.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention automatically adjusts the control strategy according to the voltage drop amplitude, allowing the natural acceleration caused by the power difference when the fault is not serious, thereby improving the dynamic process of the system; and taking timely action when the fault is serious, thereby improving the transient stability of the grid-type inverter. By setting the module action threshold Δ P max Effectively prevent over- or under-response.

[0014] (2) The present invention determines the action characteristics of the limiting module of the grid-type inverter under different degrees of fault, analyzes the impact of power limiting on the acceleration area, and accurately quantifies the transient stability boundary of the grid-type inverter under the combined action of power limiting and priority current limiting.

[0015] (3) The transient stability quantification method and system of the grid-connected inverter considering power limiting and precise mode switching of the present invention can be applied to online evaluation of the transient stability of the grid-connected inverter system under power limiting and current limiting, optimize the transient stability of the grid-connected inverter, and ensure the successful fault ride-through of new energy equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0017] Figure 1 1 is a flow chart of a method for adjusting power limit to temporarily stabilize a network device during current limiting according to an embodiment of the present invention; Figure 2 This is a block diagram of a grid-connected inverter stand-alone system according to an embodiment of the present invention; Figure 3 It is the power angle characteristic of the acceleration process of the virtual synchronous machine with different voltage drop levels; Figure 4 It is a structural diagram of a power limit setting system for temporarily stabilizing a network device during current limiting according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0020] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0021] Figure 1 FIG. 1 is a flow chart of a method for adjusting power limit to improve the temporary stability of a network device in current limiting according to an embodiment of the present invention. Figure 1 The power limit setting method for temporarily stabilizing the network-building device during current limiting in the embodiment shown may include: S101 uses a virtual synchronous machine to control the grid-type inverter, and uses a voltage-current dual closed loop to achieve constant voltage mode control of the grid-type inverter under normal operating conditions.

[0022] The grid-connected inverter adopts virtual synchronous machine control, which makes it present voltage source characteristics through double closed-loop control. The virtual synchronous machine control equation is expressed as: (1) (2) Where d is the differential operator; t For time; The phase difference between the grid-connected inverter and the grid, i.e., the power angle; ω and ω 0 are the actual angular frequency and rated angular frequency of the grid-connected inverter respectively; ω base is the base value of angular frequency; J is the virtual inertia coefficient; D is the damping coefficient; P ref and P c They are respectively the active reference value and actual active power of the grid-connected inverter.

[0023] S102, when the grid-connected system of the grid-connected inverter experiences a voltage drop on the grid side, the grid-connected inverter is triggered to enter a current limiting mode, and when the power difference exceeds the set maximum power difference, the power difference is limited to increase. Figure 2 A block diagram of a grid-connected inverter stand-alone system according to an embodiment of the present invention is given.

[0024] The grid-connected inverter uses a priority current limiting device to limit the fault current. The specific current limiting strategy is as follows: (3) Where, I c is the actual current of the grid-connected inverter; The current reference value provided for the voltage outer loop of the grid-type inverter; The current reference value actually input to the current inner loop; I cmax is the current threshold of the grid-type inverter; is the current angle, indicating I c and d The angle between the axes; e is the base of the natural logarithm.

[0025] according to Figure 3 As shown in (a) and (b), the power angle of the inverter remains unchanged at the moment of fault voltage drop, the output active power decreases, and the active reference value P ref and output value P c The difference Δ P 1 increases the virtual angular velocity, which in turn causes the active power difference to increase further. When the active power difference reaches the set value Δ P max When , the power limit link is triggered, limiting the further increase of the active power difference, thereby reducing the acceleration area of ​​the system. During the acceleration process, the power angle equation of the active power reference value is as follows: (4) Where, P ref,eq To increase the equivalent active power reference value after the power limit link; Δ P max The upper limit set for the power limit link; Δ P It is the difference between the active reference value and the actual output value.

[0026] S103, calculating the switching conditions for the grid-type inverter to switch from the constant voltage mode to the current limiting mode and the switching conditions for the grid-type inverter to switch from the current limiting mode to the constant voltage mode, and resolving the switching conditions into corresponding power angle switching conditions.

[0027] The grid-type inverter operates in constant voltage mode. When the grid-side voltage drops and the grid-type inverter is about to switch to current limiting mode, the following events occur: (5) Where, U g and Ug is the grid voltage vector and amplitude; U ref and U ref are the grid connection point voltage reference value vector and amplitude respectively; X g is the equivalent reactance of the power grid; j is an imaginary number.

[0028] Based on formula (5), the power angle switching condition for the grid-connected inverter to switch from constant voltage mode to current limiting mode can be determined: (6) The equation (6) is satisfied The range is defined as Θ, which is the power angle condition for the grid-connected inverter to switch from constant voltage mode to current limiting mode: (7) Where k is an arbitrary integer; U g is the grid voltage amplitude; U ref is the grid connection point voltage reference value amplitude; X g is the equivalent reactance of the power grid; I cmax is the current threshold of the grid-type inverter; n is the intermediate parameter.

[0029] When the grid-side fault is cleared and the grid-side voltage is restored, the grid-type inverter enters the fault recovery phase. Considering the voltage loop dynamics, the conditions for the grid-type inverter to switch from current limiting mode to constant voltage mode can be expressed as: (8) Where, U p is the grid-connected point voltage vector of the grid-connected inverter; K pu is the voltage loop proportional coefficient of the grid-type inverter.

[0030] By performing square shift processing on equation (8), the power angle switching condition for the grid-type inverter to switch from current limiting mode to constant voltage mode can be obtained.

[0031] (9) Where, The power angle switching condition for the grid-connected inverter to switch from current limiting mode to constant voltage mode; θ 1 and θ 2 are the upper and lower limits of the switching conditions, respectively. Their specific expressions are as follows: (10) Where, for a circle E Heyuan F The distance between the centers of the circles; determine the voltage vector of the grid-connected point of the grid-connected converter U p The trajectory is a circle E ;Depend on U p The dq axis components u pd and u pq A circular feasible region of F ; k is an arbitrary integer; L is the equivalent impedance.

[0032] S104 , calculating an acceleration area of ​​the grid-type inverter under power limitation according to the power shortage of the grid-type inverter at the time of the fault.

[0033] If the grid voltage drops significantly, resulting in a shortfall in active power Δ P 1>Δ P max , then the power limit always plays a role in the entire acceleration process, and the acceleration area of ​​the process can be expressed as: (11) Where, is the acceleration area of ​​the grid-type inverter in constant voltage mode; is the steady-state operating point of the system; θ clear is the power angle of the inverter when the fault is cleared; Δ P 1 is the active reference value at the moment of fault P ref and actual value P c The difference.

[0034] If the grid voltage drop is small, the active power shortage Δ P 1<Δ P max , then the power limit will not be triggered at the moment of fault occurrence, and the power angle of the system will continue to increase. As the power angle increases, the output active power of the grid-connected inverter in the current limiting mode gradually decreases, which will cause the active power difference to further increase. When the upper limit Δ of the power limit module is reached P max After that, the power limiting module is triggered. Therefore, the acceleration area of ​​this process can be expressed as: (12) Where, θ L The power angle of the inverter when the limiter module is triggered, meeting the triggering conditions of the limiter module: (13) In summary, the acceleration area of ​​the grid-type inverter with a limiting link is expressed as: (14) Where, is the acceleration area of ​​the grid-type inverter in constant voltage mode; is the steady-state operating point of the system; is the power angle of the inverter when the fault is cleared; Δ P 1 is the active reference value at the moment of fault P ref and actual value P c The difference between θ L is the power angle of the inverter when the limit module is triggered; Δ P max The upper limit set for the power limit link; is the current angle, indicating I c and d The angle between the axes; I c is the actual current of the grid-connected inverter; U g is the grid voltage amplitude; I cmax is the current threshold of the grid-connected inverter.

[0035] S105 , based on the relationship between the fault clearing angle and the power angle switching condition of the grid-type inverter, calculating the deceleration area of ​​the grid-type inverter under the action of power limiting.

[0036] Speed ​​area The expression of the fault clearing angle is divided into two cases due to the difference between the fault clearing angle and the mode switching angle. When the fault clearing angle of the grid-type inverter is When the power angle is Continue to increase when Increase to , the grid-connected inverter will enter the current limiting mode again. During the fault period, the grid-connected inverter will always operate in the current limiting mode. Therefore, the specific expression of the deceleration area is as follows: (15) Where, S - is the deceleration area; It is the unstable equilibrium point of the system in current limiting mode; The switching angle from constant voltage mode to current limiting mode; The power angle of the grid-connected inverter when the fault is cleared; X g is the equivalent reactance of the power grid; P ref It is the active power reference value at the moment of fault; P c The actual active power value at the moment of fault; is the current angle, indicating I c and d The angle between the axes; I c is the actual current of the grid-connected inverter; U g is the grid voltage amplitude; I cmax is the current threshold of the grid-type inverter; U ref is the reference value amplitude of the grid connection point voltage.

[0037] S106 , based on the equal-area rule, a setting value range of a maximum power difference of the power limiter under a transient stability condition of a grid-connected system with a single grid-connected inverter is obtained.

[0038] The transient critical stability condition of the grid-connected inverter is: (16) The critical setting value Δ required by the power limit module can be solved from the critical stability condition of the system P m , the solution process needs to first assume that the power difference at the moment of fault and Δ P m After obtaining the result, it is necessary to check Δ P m Is it consistent with the prior assumption? If it is consistent, the assumption is established. Otherwise, the assumption needs to be changed. P max The value is less than the critical setting value Δ P m When it is greater than 0, the system is transiently stable under this fault.

[0039] Figure 4 This is a schematic diagram of the structure of a power limit setting system for improving the temporary stability of the network device in the current limiting embodiment of the present invention. Figure 1 The power limit setting method for temporary stability of the network device in the current limiting process corresponds to the current limiting method, such as Figure 4 As shown, the power limit setting system for temporarily stabilizing the network device during current limiting in this embodiment may include: A constant voltage control module 401 is used to control the grid-type inverter using a virtual synchronous machine and implement constant voltage mode control of the grid-type inverter using a voltage-current dual closed loop under normal operating conditions; The current limiting control module 402 is used to trigger the grid-connected inverter to enter the current limiting mode when a voltage drop occurs on the grid side of the grid-connected inverter system, and to limit the increase of the power difference when the power difference exceeds the set maximum power difference value; A switching condition analysis module 403 is used to calculate the switching conditions for the grid-type inverter to switch from the constant voltage mode to the current limiting mode and the switching conditions for the grid-type inverter to switch from the current limiting mode to the constant voltage mode, and analyze the switching conditions into corresponding power angle switching conditions; An acceleration area calculation module 404 is configured to calculate an acceleration area of ​​the grid-type inverter under power limitation based on the power shortage of the grid-type inverter at the time of the fault; A deceleration area calculation module 405 is used to calculate the deceleration area of ​​the grid-type inverter under the action of power limiting based on the relationship between the fault clearing angle and the power angle switching condition of the grid-type inverter; The power difference upper limit setting module 406 is used to obtain a setting value range of the maximum power difference of the power limit under the condition of transient stability of the grid-connected system of the grid-connected inverter single machine based on the equal area rule.

[0040] It should be noted here that, Figure 4 The modules in the power limit setting system for temporary stability of the network device in the current limiting process are Figure 1 The various steps in the power limit adjustment method for temporary stability of the network device in the current limiting process correspond one to another, and the specific implementation process is the same, so it will not be repeated here.

[0041] The following is a schematic diagram of an electronic device. This electronic device includes a central processing unit (CPU), which can perform various actions and processes according to programs stored in read-only memory (ROM) or programs loaded from storage into random access memory (RAM). RAM also stores various programs and data required for system operation. The CPU, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0042] The following components are connected to the I / O interface: an input section including a keyboard and mouse; an output section including cathode ray tubes (CRTs), liquid crystal displays (LCDs), and speakers; a storage section including a hard disk; and a communication section including network interface cards such as local area network (LAN) cards and modems. The communication section performs communication processing via a network such as the Internet. A drive is also connected to the I / O interface as needed. Removable media such as magnetic disks, optical disks, magneto-optical disks, and semiconductor memories are installed in the drive as needed, allowing computer programs read from these media to be installed in the storage section as needed.

[0043] When the central processing unit in the electronic device of this embodiment executes the program, the following is achieved: Figure 1 The steps in the power limit adjustment method for temporarily stabilizing the network device during the boost current limiting are shown.

[0044] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer readable medium, the computer program including a computer program for executing Figure 1 In such an embodiment, the computer program can be downloaded and installed from a network via the communication portion and / or installed from a removable medium. When the computer program is executed by the central processing unit, the various functions defined in the apparatus of the present application are performed.

[0045] in, Figure 1 The computer program instructions corresponding to the method shown can also be stored in a computer readable memory that can guide a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0046] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a computer-readable storage medium, and when executed, the program can include the processes in the above-described method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0047] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A power limit setting method for improving the temporary stability of a network device during current limiting, characterized in that: include: A virtual synchronous machine is used to control the grid-connected inverter, and a voltage-current dual closed loop is used under normal operating conditions to achieve constant voltage mode control of the grid-connected inverter. When a voltage drop occurs on the grid side of the grid-connected system of the grid-connected inverter, the grid-connected inverter is triggered to enter the current limiting mode. When the power difference exceeds the set maximum power difference, the power difference is limited to increase. Calculate the switching conditions for the grid-type inverter to switch from constant voltage mode to current limiting mode and the switching conditions for the grid-type inverter to switch from current limiting mode to constant voltage mode, and resolve the switching conditions into corresponding power angle switching conditions; According to the power shortage of the grid-type inverter at the time of fault, the acceleration area of ​​the grid-type inverter under the action of power limitation is calculated; Based on the relationship between the fault clearing angle and power angle switching conditions of the grid-type inverter, the deceleration area of ​​the grid-type inverter under the action of power limitation is calculated; Based on the equal-area rule, the setting value range of the maximum power difference of the power limiter is obtained under the condition of transient stability of the grid-connected system with a single grid-connected inverter.

2. The power limit setting method for temporarily stabilizing the network device during current limiting as claimed in claim 1, characterized in that: The acceleration area of ​​the grid-type inverter under power limitation is: Where, is the acceleration area of ​​the grid-type inverter in constant voltage mode; is the steady-state operating point of the system; is the power angle of the inverter when the fault is cleared; Δ P 1 is the active power reference value at the moment of fault P ref and actual value P c The difference between θ L is the power angle of the inverter when the limiter module is triggered; Δ P max The upper limit set for the power limit link; is the current angle, indicating I c and d The angle between the axes; I c is the actual current of the grid-connected inverter; U g is the grid voltage amplitude; I cmax is the current threshold of the grid-connected inverter.

3. The power limit setting method for temporarily stabilizing a network device during current limiting as claimed in claim 1, characterized in that: The deceleration area of ​​the grid-type inverter under power limitation is: Where, S - is the deceleration area; It is the unstable equilibrium point of the system in current limiting mode; The switching angle from constant voltage mode to current limiting mode; The power angle of the grid-connected inverter when the fault is cleared; X g is the equivalent reactance of the power grid; P ref It is the active power reference value at the moment of fault; P c The actual active power value at the moment of fault; is the current angle, indicating I c and d The angle between the axes; I c is the actual current of the grid-connected inverter; U g is the grid voltage amplitude; I cmax is the current threshold of the grid-type inverter; U ref is the reference value amplitude of the grid connection point voltage.

4. The method for setting the power limit to temporarily stabilize the network device during current limiting as claimed in claim 1, characterized in that: The transient stability conditions of a grid-connected inverter single-machine system are: The acceleration area of ​​the grid-type inverter under the action of power limitation is equal to the deceleration area of ​​the grid-type inverter under the action of power limitation.

5. The power limit setting method for temporarily stabilizing a network device during current limiting as claimed in claim 1, characterized in that: The power angle conditions for the grid-connected inverter to switch from constant voltage mode to current limiting mode are: ； Where k is an arbitrary integer; U g is the grid voltage amplitude; U ref is the grid connection point voltage reference value amplitude; X g is the equivalent reactance of the power grid; I cmax is the current threshold of the grid-type inverter; is the phase difference between the grid-type converter and the grid, i.e., the power angle; n is an intermediate parameter; The range is defined as Θ.

6. The method for setting the power limit to temporarily stabilize the network device during current limiting as claimed in claim 1, characterized in that: The power angle switching conditions for the grid-connected inverter to switch from current limiting mode to constant voltage mode are: ; Where, The power angle switching condition for the grid-connected inverter to switch from current limiting mode to constant voltage mode; and are the upper and lower limits of the switching conditions respectively; k is an arbitrary integer.

7. The method for setting the power limit to temporarily stabilize the network device during current limiting as claimed in claim 1, characterized in that: When the active power difference reaches the upper limit Δ set by the power limit link P max When the power limit link is triggered, the active power difference is limited to increase further, thereby reducing the acceleration area of ​​the system; during the acceleration process, the power angle of the active reference value The equation is: Where, Δ P max The upper limit set for the power limit link; Δ P It is the difference between the active reference value and the actual output value; P ref is the active reference value; P c is the output value.

8. A power limit setting system for improving the temporary stability of a network device during current limiting, characterized in that: include: A constant voltage control module, which is used to control the grid-type inverter using a virtual synchronous machine and implement constant voltage mode control of the grid-type inverter using a voltage and current double closed loop under normal operating conditions; The current limiting control module is used to trigger the control grid-type inverter to enter the current limiting mode when the grid-type inverter grid-connected system has a voltage drop on the grid side, and limit the increase of the power difference when the power difference exceeds the set maximum power difference; A switching condition analysis module is used to calculate the switching conditions for the grid-type inverter to switch from constant voltage mode to current limiting mode and the switching conditions for the grid-type inverter to switch from current limiting mode to constant voltage mode, and analyze the switching conditions into corresponding power angle switching conditions; An acceleration area calculation module, which is used to calculate the acceleration area of ​​the grid-type inverter under the action of power limitation based on the power shortage of the grid-type inverter at the time of failure; A deceleration area calculation module is used to calculate the deceleration area of ​​the grid-type inverter under the action of power limiting based on the relationship between the fault clearing angle and the power angle switching condition of the grid-type inverter; The power difference upper limit setting module is used to obtain the setting value range of the maximum power difference of the power limit under the condition of transient stability of the grid-connected system of the grid-connected inverter single machine based on the equal area rule.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for adjusting the power limit for temporary stability of a network-building device during current limiting are implemented as described in any one of claims 1 to 7.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the power limit adjustment method for temporarily stabilizing a network device during current limiting are implemented as described in any one of claims 1-7.

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