Transient stability evaluation method and system for network construction device considering damping and current limiting

Abstract

The invention relates to the technical field of power grids, and provides a network construction device transient stability evaluation method and system considering damping and current limiting, and the method comprises the steps: based on the actual angular frequency of a virtual synchronous machine, the rated angular frequency of a power grid, and the active reference value of a network construction type inverter converter, combining the transient stability critical condition of the virtual synchronous machine and an energy function, and evaluating the transient stability of the network construction device; carrying out simultaneous solution to obtain a critical fault clearing angle so as to quantify the transient stability of the network construction device; wherein the transient stability critical condition of the virtual synchronous machine is obtained by introducing an equivalent damping deceleration area and incorporating the equivalent damping deceleration area into an equal area rule, and calculation of the damping deceleration area is simplified by analyzing the concavity and convexity of an angular frequency track. The conservative property of a traditional transient stability criterion is effectively reduced, and a more accurate design basis is provided for control parameter setting of the network-forming converter.

Description

Technical Field

[0001] This invention belongs to the field of power grid technology, and in particular relates to a method and system for evaluating the transient stability of power grid devices that takes into account damping and current limiting. Background Technology

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

[0003] Virtual synchronous machine control, by mimicking the rotor motion equations and excitation circuit of a synchronous machine, enables the voltage amplitude and phase of the converter source to remain constant during disturbances, exhibiting voltage source characteristics and effectively improving the grid's immunity. However, during grid voltage dips, the fault current in grid-connected inverters can easily exceed the overcurrent threshold of semiconductor components, necessitating current-limiting control to protect the grid-connected inverter.

[0004] Traditional synchronous generators have relatively large inertia and small damping terms, so the influence of damping terms on acceleration and deceleration processes is neglected when analyzing transient stability using the equal-area method. However, according to power grid specifications, the damping coefficient of a virtual synchronous machine should be in the range of 8 to 50 p.u., a value significantly higher than that of a synchronous generator. This leads to considerable conservatism when analyzing the transient stability of a virtual synchronous machine. The damping term is highly coupled with the angular frequency in the differential equation of motion, and the mode switching problem introduced by current limiting further complicates the quantification of the damping effect of the grid-connected device during transient processes. Currently, numerical integration methods are mostly used to address the influence of damping terms; however, methods for considering current limiting switching and analyzing the damping effect from an energy perspective, as well as quantification methods, are rarely discussed. Summary of the Invention

[0005] To address the technical problems mentioned above, this invention provides a transient stability assessment method and system for grid-connected devices that considers damping and current limiting. This method can accurately quantify the damping dissipation energy throughout the fault process. By introducing an equivalent damping deceleration area and incorporating it into the equal area rule, the conservatism of traditional transient stability criteria is effectively reduced, providing a more accurate design basis for the control parameter tuning of grid-connected converters.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a transient stability evaluation method for a grid-connected device that takes into account damping and current limiting, comprising: Obtain the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the power grid, and the active power reference value of the grid-type inverter converter; Based on the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the power grid, and the active power reference value of the grid-connected inverter converter, the critical fault clearing angle is obtained by simultaneously solving the transient stability critical condition and energy function of the virtual synchronous machine to quantify the transient stability of the grid-connected device. The transient stability critical condition of the virtual synchronous machine is obtained by introducing an equivalent damping deceleration area and incorporating it into the equal area rule, and the calculation of the damping deceleration area is simplified by analyzing the concavity and convexity of the angular frequency trajectory.

[0007] Furthermore, under the action of virtual impedance or ring current limiting, the transient stability critical condition of the virtual synchronous machine is: ;in, To accelerate the area, θ0 is the output active power of the virtual synchronous machine during the fault, and θ0 is the steady-state operating power angle under constant voltage mode. To account for the damping effect and the maximum deceleration area during current limiting switching, P ref This is the active power reference value for grid-type inverter converters.

[0008] Furthermore, the maximum deceleration area considering damping effect and current limiting switching is... ;in, P represents the output power of the virtual synchronizer. ref θ is the active power reference value for the grid-connected inverter converter. CCA This is the critical fault clearing angle.

[0009] Furthermore, the energy function is: Where θ0 is the steady-state operating power angle under constant voltage mode, ω0 is the per-unit value of the rated angular frequency of the power grid, and ω b Here, J is the reference value for angular frequency, D is the virtual inertia, and P is the damping coefficient. ref ω is the active power reference value for the grid-connected inverter converter. CCA θ is the angular frequency at which fault clearance occurs under critical stability conditions. CCA This is the critical fault clearing angle.

[0010] Furthermore, the damping deceleration areas after fault clearance under the action of virtual impedance are as follows: In the formula, D is the damping coefficient, and ω CCA ω0 represents the angular frequency at which fault clearance occurs under critical stability conditions, and ω0 is the per-unit value of the rated angular frequency of the power grid. For the unstable equilibrium point under the action of virtual impedance, θ CCA This is the critical fault clearing angle.

[0011] Furthermore, the damping deceleration areas after fault clearance under the annular limiting effect are as follows: In the formula, D is the damping coefficient, and ω CCAω0 is the angular frequency at which fault clearance occurs under critical stability conditions, θ is the power angle, and ω is the per-unit value of the actual angular frequency of the virtual synchronizing machine. CCA This is the critical fault clearing angle. This is an unstable equilibrium point under the action of ring-shaped amplitude limiting. yes The left limit.

[0012] Furthermore, the damping deceleration area during the fault is: In the formula, θ0 is the steady-state operating power angle under constant voltage mode, θ CCA Where ω is the critical fault clearing angle, D is the damping coefficient, and ω is the critical fault clearing angle. CCA ω0 is the angular frequency at which faults are cleared under critical stability conditions, ω0 is the per-unit value of the rated angular frequency of the power grid, and ω is the per-unit value of the actual angular frequency of the virtual synchronizing machine.

[0013] A second aspect of the present invention provides a transient stability evaluation system for a network structure considering damping and current limiting, comprising: The data acquisition module is configured to acquire the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the power grid, and the active power reference value of the grid-type inverter converter. The stability assessment module is configured to: based on the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the grid, and the active power reference value of the grid-connected inverter converter, and combined with the transient stability critical condition and energy function of the virtual synchronous machine, solve simultaneously to obtain the critical fault clearing angle, so as to quantify the transient stability of the grid-connected device; wherein, the transient stability critical condition of the virtual synchronous machine is obtained by introducing an equivalent damping deceleration area and incorporating it into the equal area rule, and the calculation of the damping deceleration area is simplified by analyzing the concavity and convexity of the angular frequency trajectory.

[0014] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the transient stability evaluation method for a network device taking into account damping and current limiting as described above.

[0015] A fourth aspect of the present invention provides a computer device including a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, wherein the processor executes the program to implement the steps in the transient stability evaluation method for a network device considering damping and current limiting as described above.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention can accurately quantify the damping dissipation energy throughout the entire fault process. By introducing an equivalent damping deceleration area and incorporating it into the equal area rule, it effectively reduces the conservatism of traditional transient stability criteria and provides a more accurate design basis for the control parameter tuning of grid-type converters.

[0017] This invention innovatively proposes a method to simplify the calculation of damped deceleration area by analyzing the concavity and convexity of the angular frequency trajectory, avoiding the complex process of solving differential equations by traditional numerical integration methods, and significantly improving the efficiency and practicality of transient stability boundary calculation.

[0018] This invention is the first to realize a unified quantitative framework for the damping effect under two mainstream current limiting strategies: virtual impedance and ring current limiting. Through a unified power angle switching model and a damping area simplification method, it provides a general theoretical tool for comparing and optimizing the transient performance of different current limiting schemes. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a flowchart of a transient stability evaluation method for a network structure device that takes into account damping and current limiting, according to Embodiment 1 of the present invention. Figure 2 This is a block diagram of a grid-connected inverter single-unit grid-connected system according to Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the power angle characteristics of the virtual synchronous machine under the action of virtual impedance and ring current limiting strategy in Embodiment 1 of the present invention. Figure 4 This is a simplified schematic diagram of the equivalent damping deceleration area under the action of virtual impedance and ring current limiting strategy in Embodiment 1 of the present invention. Figure 5 This is a schematic diagram of the structure of a computer device according to Embodiment 4 of the present invention. Detailed Implementation

[0021] 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.

[0022] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] Example 1 This embodiment provides a transient stability evaluation method for a network structure device that takes into account damping and current limiting.

[0024] This embodiment provides a transient stability assessment method for a network device that takes into account damping and current limiting. It can quantify the impact of the damping term during the period from the occurrence of a fault to the recovery of steady state, and at the same time consider the switching of virtual synchronous machine mode to obtain a more accurate transient stability boundary.

[0025] This embodiment provides a transient stability evaluation method for a network structure device that considers damping and current limiting, comprising the following steps: S1: The grid-type inverter converter adopts virtual synchronous machine control and uses voltage and current dual closed loop to achieve constant voltage mode control under normal operating conditions.

[0026] In step S1, the grid-type inverter converter adopts the following... Figure 2 The virtual synchronous machine control shown simulates the second-order rotor motion equation of a synchronous machine, providing inertia and damping support for the power system. Its control equation is expressed as: (1); (2); In the formula, d is the differential operator; θ is the power angle, i.e., the phase angle difference between the virtual synchronizing machine and the power grid; t is time; ω and ω0 are the per-unit values ​​of the actual angular frequency of the virtual synchronizing machine and the rated angular frequency of the power grid, respectively; ω b J is the reference value for angular frequency; D is the virtual inertia; P is the damping coefficient; ref and P c These are the active power reference value and the actual active power output value of the grid-connected inverter converter, respectively.

[0027] S2: The virtual synchronous machine employs a ring or virtual impedance current limiting device. In the event of a fault, the current limiting device is triggered to prevent overcurrent damage to the power electronic equipment. The current limiting device introduces a switching problem. The switching conditions between the virtual synchronous machine and the current limiting mode are derived, and the switching conditions are analyzed as power angle switching conditions, and the output power expression is derived.

[0028] In step S2, the damping quantization method of the loop and virtual impedance current limiting device is studied, and the specific current limiting strategy is as follows: When a grid fault occurs, the loop current limiter directly limits the amplitude of the current reference without changing its phase angle. Its control strategy can be expressed as: (3); In the formula, This is the reference value for the current output of the current limiter; This is the current reference value output by the voltage loop; The set output current threshold for the virtual synchronous machine.

[0029] Unlike the ring current limiting strategy, the virtual impedance method achieves current limiting by lowering the grid connection point voltage reference value. Therefore, the virtual synchronous machine can maintain its voltage source characteristics during faults. The specific method for setting the virtual impedance is as follows: (4); In the formula, R VI and X VI These are virtual resistance and virtual reactance, respectively; The current output by the virtual synchronous machine; when the actual output current I of the GFM converter... c Greater than threshold I cmax When the impedance is 0, a virtual impedance is applied; otherwise, the virtual impedance is set to 0.

[0030] Under normal circumstances, the virtual synchronous machine operates in constant voltage mode, with the voltage loop and current loop directly connected. Furthermore, the current loop can always quickly track the current reference value, therefore... When the grid voltage drops, the conditions for mode switching can be calculated based on the main circuit structure and Ohm's law: (5); In the formula, U g and U g For the grid voltage vector and magnitude; U ref and U ref These are the reference voltage vector and magnitude at the grid connection point, respectively; X g is the equivalent reactance of the power grid; j is an imaginary number.

[0031] Based on equation (5), the power angle switching condition for the grid-connected inverter converter to switch from constant voltage mode to current-limiting mode can be obtained: (6); In the formula, n This is the cosine value corresponding to the critical switching angle for current limiting.

[0032] The range of θ satisfying equation (6) is defined as Θ, which is the power angle condition for the grid-type inverter converter to switch from constant voltage mode to current-limiting mode: (7); In the formula, k is any integer.

[0033] After obtaining the power angle switching conditions of the virtual synchronous machine, the power angle switching model can be expressed as: (8); In the formula, and These represent the output power of the VSG in constant voltage mode and current limiting mode, respectively.

[0034] Ignore grid resistance. It can be represented as: (9); Under the effect of ring limiting, the virtual synchronous machine can also be equivalent to a constant voltage source connected in series with an equivalent impedance. Therefore, under the effects of ring limiting and virtual impedance, the output power of the virtual synchronous machine... The expression is similar and can be represented as: (10); (11); In the formula, This refers to the output power under ring-shaped limiting. This represents the output power under the influence of virtual impedance.

[0035] Combining equations (9) and (11), as follows Figure 3 The diagram shows the power angle curves of the virtual synchronous machine under virtual impedance and ring limiting conditions, respectively.

[0036] S3: From an energy perspective, the equal area criterion ensures that all kinetic energy is converted into potential energy before the virtual synchronous machine crosses the unstable equilibrium point. Before the angular frequency decelerates to zero, the damping term has a decelerating effect on the angular frequency, which can be regarded as dissipated energy or equivalent damping deceleration area.

[0037] In step S3, from the second-order motion equations (1) and (2) of the virtual synchronizer, we can obtain: (12); For both sides of equation (12) Integrating, we get: (13); Based on equation (13), from an energy perspective: the equal area criterion essentially ensures that the virtual synchronous machine can convert all kinetic energy into potential energy before crossing the unstable equilibrium point, i.e., the angular frequency difference decelerates to zero. Meanwhile, the damping term... It also remains negative, and has a decelerating effect on the angular frequency. It can be regarded as energy dissipation or equivalent damping deceleration area, that is: (14); In the formula, S D This represents the equivalent damping deceleration area.

[0038] S4: A method is proposed to simplify the equivalent damping deceleration area based on concavity and convexity. The concavity and convexity of the ω trajectory are determined by segmenting the trajectory with mode switching and fault clearing as boundaries, and then the calculation of the damping deceleration area is simplified by utilizing the concavity and convexity.

[0039] In step S4, the equivalent damped deceleration area depends on the trajectory of the angular frequency ω, which requires solving a differential equation. To avoid solving the differential equation, the problem can be simplified by considering the concavity and convexity of the angular frequency ω trajectory.

[0040] Throughout the fault recovery process, both mode switching and fault clearing cause changes in the output active power of the grid-type converter, and the concavity / convexity of the ω-trajectory may also change with mode switching and fault clearing. Therefore, for both virtual impedance and ring current limiting strategies, it is necessary to analyze the concavity / convexity of the ω-trajectory in segments, dividing the fault recovery process into the following three segments: fault occurrence to fault clearing, fault clearing to mode switching, and mode switching to the critical stable operating point. If the fault is severe or lasts for a long time, and no mode switching occurs after fault clearing, the three ω-trajectory segments are merged into two segments: fault occurrence to fault clearing and fault clearing to the critical stable operating point.

[0041] S5: Calculate the simplified damped deceleration area to obtain the maximum acceleration / deceleration area considering damping effects and current-limiting switching. Based on the equal area rule, propose a transient stability criterion for the first pendulum.

[0042] In step S5, using the method proposed in step S4, the two ω-trajectories with fault clearance as the boundary are analyzed under extreme fault conditions. It is determined that under the action of virtual impedance and ring limiting, from fault clearance to the critical stable operating point, these two ω-trajectories are concave and convex, respectively. The damping deceleration areas after fault clearance under virtual impedance and ring limiting can be simplified as follows: (15); (16); In the formula, and ω represents the damped deceleration area after fault clearance under virtual impedance and ring limiting, respectively. CCA The angular frequency at which fault clearance occurs under critical stability conditions. and These represent the unstable equilibrium points of the system under virtual impedance and ring limiting conditions, respectively. yes The left limit, θ CCA This is the critical fault clearing angle.

[0043] During the fault, both the virtual impedance and the ω-trajectory of the ring limiting are concave; therefore, the damping deceleration area during the fault can be simplified as: (17); In the formula, θ0 is the steady-state operating power angle of the system under constant voltage mode.

[0044] Therefore, the sum of the virtual impedance and the damped deceleration area under the ring limiting effect is... , like Figure 4 The following are respectively: (18); (19); In summary, considering the damping effect and the maximum deceleration area during current limiting switching... It can be represented as: (20); In the formula, This represents the total damping area; This represents the maximum deceleration area under current limiting mode. This represents an unstable equilibrium point under the rate-limiting mode.

[0045] Based on the equal-area rule, the transient stability criterion of the first pendulum can be expressed as: (twenty one); In the formula, To accelerate the area, This represents the active power output of the virtual synchronous machine during a fault.

[0046] S6: Based on the transient stability criterion of the first pendulum, a more accurate critical fault clearing angle is calculated considering the damping deceleration area and the current limiting switching condition of the virtual synchronous machine.

[0047] In step S6, under the action of virtual impedance or ring current limiting, the transient stability critical condition of the virtual synchronous machine can be written as: (twenty two); Equation (22) also includes an intermediate variable. Based on the energy conservation equation (13), during a fault, the potential energy change of the virtual synchronizer is completely converted into kinetic energy and dissipated energy. Accordingly, the energy function for this process is as follows: (twenty three); The damping term in equation (23) also needs simplification. Contrary to the simplification approach used in calculating the equivalent damped deceleration area, the damping term needs to be further expanded into a rectangle, rather than a triangle. At this point, the calculated... It will be smaller than the actual value, which ensures the conservatism of using triangles to calculate the equivalent damping deceleration area. Meanwhile, the calculation of the critical fault clearing angle needs to consider the most severe fault, i.e., a three-phase short-circuit fault, to ensure that the obtained critical fault clearing angle can guarantee the transient stability of the virtual synchronous machine under any fault. In summary, equation (23) can be simplified to: (twenty four); At this point, the precise critical fault clearing angle considering damping effects and mode switching can be obtained by simultaneously solving equations (22) and (24).

[0048] Example 2 This embodiment provides a transient stability evaluation system for a network structure device that considers damping and current limiting, such as... Figure 2 As shown, it includes: The data acquisition module is configured to acquire the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the power grid, and the active power reference value of the grid-type inverter converter. The stability assessment module is configured to: based on the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the grid, and the active power reference value of the grid-connected inverter converter, and combined with the transient stability critical condition and energy function of the virtual synchronous machine, solve simultaneously to obtain the critical fault clearing angle, so as to quantify the transient stability of the grid-connected device; wherein, the transient stability critical condition of the virtual synchronous machine is obtained by introducing an equivalent damping deceleration area and incorporating it into the equal area rule, and the calculation of the damping deceleration area is simplified by analyzing the concavity and convexity of the angular frequency trajectory.

[0049] It should be noted that each module in this embodiment corresponds one-to-one with each step in Embodiment 1, and their specific implementation processes are the same, so they will not be repeated here.

[0050] Example 3 This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the transient stability evaluation method for a network structure considering damping and current limiting as described in Embodiment 1 above.

[0051] Example 4 This embodiment provides a computer device, such as... Figure 5 As shown, the device includes a computer-readable storage medium 1003, a processor 1001, a communication interface 1002, and a computer program stored on the computer-readable storage medium 1003 and executable on the processor 1001. The processor 1001, communication interface 1002, and computer-readable storage medium 1003 can be connected via a bus or other means. The communication interface 1002 is used to receive and transmit data. When the processor 1001 executes the program, it implements the steps in the transient stability evaluation method for a network structure considering damping and current limiting as described in Embodiment 1 above.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating the transient stability of a network structure considering damping and current limiting, characterized in that, include: Obtain the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the power grid, and the active power reference value of the grid-type inverter converter; Based on the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the power grid, and the active power reference value of the grid-connected inverter converter, the critical fault clearing angle is obtained by simultaneously solving the transient stability critical condition and energy function of the virtual synchronous machine to quantify the transient stability of the grid-connected device. The transient stability critical condition of the virtual synchronous machine is obtained by introducing an equivalent damping deceleration area and incorporating it into the equal area rule, and the calculation of the damping deceleration area is simplified by analyzing the concavity and convexity of the angular frequency trajectory.

2. The transient stability evaluation method for a network structure considering damping and current limiting as described in claim 1, characterized in that, Under virtual impedance or ring current limiting, the transient stability critical condition of the virtual synchronous machine is: ;in, To accelerate the area, θ0 is the output active power of the virtual synchronous machine during the fault, and θ0 is the steady-state operating power angle under constant voltage mode. To account for the damping effect and the maximum deceleration area during current limiting switching, P ref This is the active power reference value for grid-type inverter converters.

3. The transient stability evaluation method for a network structure considering damping and current limiting as described in claim 2, characterized in that, The maximum deceleration area considering damping effect and current limiting switching is: ;in, P represents the output power of the virtual synchronizer. ref θ is the active power reference value for the grid-connected inverter converter. CCA This is the critical fault clearing angle.

4. The transient stability evaluation method for a network structure considering damping and current limiting as described in claim 1, characterized in that, The energy function is: Where θ0 is the steady-state operating power angle under constant voltage mode, ω0 is the per-unit value of the rated angular frequency of the power grid, and ω b Here, J is the reference value for angular frequency, D is the virtual inertia, and P is the damping coefficient. ref ω is the active power reference value for the grid-connected inverter converter. CCA θ is the angular frequency at which fault clearance occurs under critical stability conditions. CCA This is the critical fault clearing angle.

5. The transient stability evaluation method for a network structure considering damping and current limiting as described in claim 1, characterized in that, The damping deceleration areas after fault clearance under virtual impedance are as follows: In the formula, D is the damping coefficient, and ω CCA ω0 represents the angular frequency at which fault clearance occurs under critical stability conditions, and ω0 is the per-unit value of the rated angular frequency of the power grid. For the unstable equilibrium point under the action of virtual impedance, θ CCA This is the critical fault clearing angle.

6. The transient stability evaluation method for a network structure considering damping and current limiting as described in claim 1, characterized in that, The damping deceleration areas after fault clearance under annular limiting are as follows: In the formula, D is the damping coefficient, and ω CCA ω0 is the angular frequency at which fault clearance occurs under critical stability conditions, θ is the power angle, and ω is the per-unit value of the actual angular frequency of the virtual synchronizing machine. CCA This is the critical fault clearing angle. This is an unstable equilibrium point under the action of ring-shaped amplitude limiting. yes The left limit.

7. The transient stability evaluation method for a network structure considering damping and current limiting as described in claim 1, characterized in that, The damping deceleration area during the fault is: In the formula, θ0 is the steady-state operating power angle under constant voltage mode, θ CCA Where ω is the critical fault clearing angle, D is the damping coefficient, and ω is the critical fault clearing angle. CCA ω0 is the angular frequency at which faults are cleared under critical stability conditions, ω0 is the per-unit value of the rated angular frequency of the power grid, and ω is the per-unit value of the actual angular frequency of the virtual synchronizing machine.

8. A transient stability evaluation system for a network structure considering damping and current limiting, characterized in that, include: The data acquisition module is configured to acquire the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the power grid, and the active power reference value of the grid-type inverter converter. The stability assessment module is configured to: based on the actual angular frequency of the virtual synchronous machine, the rated angular frequency of the grid, and the active power reference value of the grid-connected inverter converter, and combined with the transient stability critical condition and energy function of the virtual synchronous machine, solve simultaneously to obtain the critical fault clearing angle, so as to quantify the transient stability of the grid-connected device; wherein, the transient stability critical condition of the virtual synchronous machine is obtained by introducing an equivalent damping deceleration area and incorporating it into the equal area rule, and the calculation of the damping deceleration area is simplified by analyzing the concavity and convexity of the angular frequency trajectory.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by the processor, the program implements the steps in the transient stability evaluation method for a network structure considering damping and current limiting as described in any one of claims 1-7.

10. A computer device comprising a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the transient stability evaluation method for a network structure device that takes into account damping and current limiting as described in any one of claims 1-7.

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