Multi-machine frequency response analysis method, apparatus, device, medium, and program product

Abstract

The application discloses a kind of multi-machine frequency response analysis method, device, equipment, medium and program product, it is related to the multi-machine frequency response modeling analysis technical field of enhanced SVG and distributed phase modifier, including: inputting preset disturbance power in the multi-machine frequency response model of target multi-machine grid-connected system, obtains the grid frequency variation of target multi-machine grid-connected system;Wherein, multi-machine frequency response model is based on the first equivalent frequency response model of phase modifier cluster access grid and the second equivalent frequency response model of enhanced SVG access grid is constructed, and is configured to reflect the functional relationship between disturbance power injected into grid and grid frequency variation, phase modifier cluster includes multiple distributed phase modifier;Based on grid frequency variation, the frequency stability of target multi-machine grid-connected system is analyzed.The application can realize the systematic frequency response analysis of enhanced SVG and distributed phase modifier multi-machine grid connection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multi-machine frequency response modeling analysis of enhanced SVG and distributed phase modulators, and particularly relates to a multi-machine frequency response analysis method, device, equipment, medium and program product. BACKGROUND

[0002] To improve the frequency response capability of the power grid, enhanced SVG (Static Var Generator) and distributed phase modulators can be connected to the power grid to form a multi-machine grid-connected system to meet the dynamic power support of the power grid.

[0003] However, in the related art, the stability analysis of the multi-machine grid-connected system formed by the enhanced SVG and the distributed phase modulator mostly focuses on the modeling analysis of voltage stability, and there is still a lack of systematic analysis of the active-frequency response of the multi-machine grid-connected system. SUMMARY

[0004] The main purpose of the present application is to provide a multi-machine frequency response analysis method, device, equipment, medium and program product, aiming to solve the technical problem of the lack of systematic analysis method of the active-frequency response of the multi-machine grid-connected system of the enhanced SVG and the distributed phase modulator in the related art.

[0005] To achieve the above purpose, the present application provides a multi-machine frequency response analysis method, which comprises:

[0006] inputting a preset disturbance power into a multi-machine frequency response model of a target multi-machine grid-connected system to obtain a power grid frequency change of the target multi-machine grid-connected system; wherein the multi-machine frequency response model is constructed based on a first equivalent frequency response model of a phase modulator cluster connected to the power grid and a second equivalent frequency response model of an enhanced SVG connected to the power grid, and is configured to reflect the functional relationship between the disturbance power injected into the power grid and the power grid frequency change, and the phase modulator cluster comprises a plurality of distributed phase modulators;

[0007] based on the power grid frequency change, analyzing the frequency stability of the target multi-machine grid-connected system.

[0008] In an embodiment, before the step of inputting a preset disturbance power into a multi-machine frequency response model of a target multi-machine grid-connected system to obtain a power grid frequency change of the target multi-machine grid-connected system, the method further comprises:

[0009] constructing a first equivalent frequency response model; wherein the first equivalent frequency response model is used to characterize the active response characteristics of the phase modulator cluster to the power grid frequency change;

[0010] constructing a second equivalent frequency response model; wherein the second equivalent frequency response model is used to represent the active power response characteristic of the enhanced SVG to the grid frequency variation;

[0011] Based on the first equivalent frequency response model and the second equivalent frequency response model, a multi-machine frequency response model corresponding to the multi-machine grid-connected system after the enhanced SVG and the cluster of distributed phase-modulators are connected to the grid is constructed.

[0012] In an embodiment, the step of constructing the first equivalent frequency response model comprises:

[0013] obtaining electrical parameters corresponding to each distributed phase-modulator in the multi-machine grid-connected system; wherein the electrical parameters include equivalent inertia, equivalent damping coefficient, and equivalent reactance between the distributed phase-modulator and the grid;

[0014] weighting average of all equivalent inertias, equivalent damping coefficients, and equivalent reactances is performed with the phase-modulator capacity of each distributed phase-modulator as the weight to obtain aggregated equivalent inertia, aggregated equivalent damping coefficient, and aggregated equivalent reactance of the cluster of distributed phase-modulators;

[0015] Based on the aggregated equivalent inertia, the aggregated equivalent damping coefficient, and the aggregated equivalent reactance, the first equivalent frequency response model is constructed.

[0016] In an embodiment, the expression of the first equivalent frequency response model is:

[0017]

[0018] wherein, P seq is the active response power of the cluster of distributed phase-modulators, f g is the grid frequency variation, ω 0 is the rated angular frequency, X eq is the aggregated equivalent reactance, H eq is the aggregated equivalent inertia, D eq is the aggregated equivalent damping coefficient, s is the Laplace operator.

[0019] In an embodiment, the step of constructing the second equivalent frequency response model comprises:

[0020] Based on the principle of direct-current voltage self-synchronization control of the enhanced SVG, a first correlation relationship between the reference phase angle variation and the direct-current voltage variation of the enhanced SVG is determined;

[0021] determine a second correlation relationship between a DC voltage variation of the enhanced SVG and an active response power of the enhanced SVG based on a DC capacitor characteristic of the enhanced SVG;

[0022] determine a third correlation relationship between a phase angle variation of the enhanced SVG and the active response power of the enhanced SVG based on grid-connection line parameters of the enhanced SVG; the grid-connection line parameters include a virtual inductance, a filter inductance, and an equivalent impedance between the enhanced SVG and the power grid;

[0023] construct a second equivalent frequency response model based on the first correlation relationship, the second correlation relationship, and the third correlation relationship.

[0024] In an embodiment, an expression of the second equivalent frequency response model is:

[0025]

[0026] wherein, P e is the active response power of the enhanced SVG, f g is a power grid frequency variation, ω 0 is a rated angular frequency, X V is a virtual inductance of the enhanced SVG, X f is a filter inductance of the enhanced SVG, Z L is an equivalent impedance between the enhanced SVG and the power grid, V ref is a voltage reference value of the enhanced SVG, V g is a power grid voltage value, C dc is a DC capacitor value of the enhanced SVG, k P is a control proportional coefficient of DC voltage self-synchronization control, k D is a control differential coefficient of DC voltage self-synchronization control, T f is an inertia time constant of DC voltage self-synchronization control, s is a Laplace operator.

[0027] In addition, to achieve the above object, the application further provides a multi-machine frequency response analysis device, which comprises:

[0028] The disturbance input module is configured to input a preset disturbance power into a multi-machine frequency response model of the target multi-machine grid-connected system to obtain a grid frequency variation of the target multi-machine grid-connected system. The multi-machine frequency response model is constructed based on a first equivalent frequency response model of a phase-modulator cluster accessing the grid and a second equivalent frequency response model of an enhanced SVG accessing the grid, and is configured to reflect a functional relationship between the disturbance power injected into the grid and the grid frequency variation. The phase-modulator cluster includes a plurality of distributed phase-modulators.

[0029] The frequency analysis module is configured to analyze the frequency stability of the target multi-machine grid-connected system based on the grid frequency variation.

[0030] In addition, to achieve the above-mentioned purpose, the present application further provides a multi-machine frequency response analysis device, which comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the computer program is configured to implement the steps of the multi-machine frequency response analysis method as described above.

[0031] In addition, to achieve the above-mentioned purpose, the present application further provides a storage medium, which is a computer-readable storage medium, and the storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the multi-machine frequency response analysis method as described above.

[0032] In addition, to achieve the above-mentioned purpose, the present application further provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to implement the steps of the multi-machine frequency response analysis method as described above.

[0033] The one or more technical solutions provided by the present application have at least the following technical effects:

[0034] The multi-machine frequency response analysis method provided in the application can directly input a preset disturbance power into a multi-machine frequency response model of a target multi-machine grid-connected system to be analyzed when performing frequency response analysis on the multi-machine grid-connected system composed of the enhanced SVG and the plurality of distributed phase modulators. The multi-machine frequency response model is constructed based on a first equivalent frequency response model of the phase modulator cluster accessing the power grid and a second equivalent frequency response model of the enhanced SVG accessing the power grid. The two equivalent frequency response models are integrated into a unified multi-machine frequency response model, which accurately corresponds to the multi-machine grid-connected scenario of the enhanced SVG and the distributed phase modulators. The multi-machine frequency response model is configured to reflect the functional relationship between the disturbance power injected into the power grid and the power grid frequency change amount. By inputting the preset disturbance power (simulating the actual active disturbance in the power grid), the power grid frequency change amount corresponding to the disturbance power can be directly obtained. The power grid frequency change amount is a core quantitative index of the frequency response capability. Therefore, the frequency stability of the target multi-machine grid-connected system can be quickly and accurately analyzed based on the power grid frequency change amount, and a decision basis is provided for subsequent optimization control. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the application or the related art, the accompanying drawings needed to be used in the embodiment or related art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0037] Figure 1 Flowchart of the multi-machine frequency response analysis method provided for Embodiment One of the application Figure 1 ;

[0038] Figure 2 Flowchart of the multi-machine frequency response analysis method provided for Embodiment One of the application Figure 2 ;

[0039] Figure 3 Frequency response control block diagram for a plurality of distributed phase modulators connected to the grid

[0040] Figure 4 Frequency response control block diagram for a plurality of distributed phase modulators connected to the grid

[0041] Figure 5 Enhanced SVG control strategy and grid connection schematic

[0042] Figure 6 Frequency response control block diagram for a multi-machine grid-connected system with coordinated phase modulator cluster and enhanced SVG

[0043] Figure 7 A schematic diagram of a brief process for constructing a multi-machine frequency response model in a multi-machine frequency response analysis method;

[0044] Figure 8 A schematic diagram of a module structure of a multi-machine frequency response analysis device according to an embodiment of the present application;

[0045] Figure 9 A schematic diagram of a device structure of a hardware operating environment involved in a multi-machine frequency response analysis method according to an embodiment of the present application.

[0046] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0047] It should be understood that the specific embodiments described herein are merely intended to explain the technical solutions of the present application, and are not intended to limit the present application.

[0048] In order to better understand the technical solutions of the present application, the specific embodiments will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] The main solution of the embodiment of the present application is: inputting a preset disturbance power into a multi-machine frequency response model of a target multi-machine grid-connected system, obtaining a grid frequency variation of the target multi-machine grid-connected system; wherein the multi-machine frequency response model is constructed based on a first equivalent frequency response model of a phase modifier cluster accessing a power grid and a second equivalent frequency response model of an enhanced SVG accessing the power grid, and is configured to reflect a functional relationship between a disturbance power injected into the power grid and the grid frequency variation, the phase modifier cluster including a plurality of distributed phase modifiers; based on the grid frequency variation, analyzing the frequency stability of the target multi-machine grid-connected system.

[0050] With large-scale renewable energy accessing the power grid, the inertia level of the power system is continuously reduced, and the inertia and frequency support capability provided by the synchronous generator is gradually weakened; at the same time, the penetration rate of intermittent power sources such as distributed energy (e.g. wind power, photovoltaic) is increasing, leading to intensified grid frequency fluctuations. In order to improve the grid frequency response capability, the enhanced SVG and the distributed synchronous condenser (Distributed Synchronous Condenser) as new power electronic devices are widely used in the power grid; these devices can realize dynamic support for the power grid by quickly adjusting active power and reactive power.

[0051] In the related art, for the collaborative operation scene of the enhanced SVG and the distributed phase modifier jointly accessing the power grid, most attention is paid to dynamic / transient voltage stability; that is, the stability analysis of the multi-machine grid-connected system composed of the enhanced SVG and the distributed phase modifier mostly focuses on modeling analysis of voltage stability. In the frequency analysis facing multiple scenes and multiple disturbances, the detailed electromagnetic model is time-consuming and difficult to implement in parameter influence or online calculation, so an equivalent model is needed for rapid evaluation. However, the equivalent model in the related art does not consider the multi-machine grid-connected situation of the collaborative operation of the enhanced SVG and the distributed phase modifier, and it is still difficult to realize the systematic analysis of the active-frequency response of the multi-machine grid-connected system.

[0052] The present application provides a solution, when analyzing the frequency response of the multi-machine grid-connected system composed of the enhanced SVG and multiple distributed phase modifiers, the preset disturbance power can be directly input into the multi-machine frequency response model of the target multi-machine grid-connected system to be analyzed; the multi-machine frequency response model is constructed based on the first equivalent frequency response model of the phase modifier cluster accessing the power grid and the second equivalent frequency response model of the enhanced SVG accessing the power grid, and the two equivalent frequency response models are integrated into a unified multi-machine frequency response model, which accurately corresponds to the multi-machine grid-connected scene of the enhanced SVG and the distributed phase modifier. The multi-machine frequency response model is configured to reflect the functional relationship between the disturbance power injected into the power grid and the power grid frequency change, and by inputting the preset disturbance power (simulating the active disturbance in the actual power grid), the power grid frequency change corresponding to the disturbance power can be directly obtained; the power grid frequency change is a core quantitative index of frequency response capability, and thus the frequency stability of the target multi-machine grid-connected system can be quickly and accurately analyzed based on the power grid frequency change, and a decision basis is provided for subsequent optimization control.

[0053] It should be noted that the execution subject of the embodiment is a multi-machine frequency response analysis device, which can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, etc., or an electronic device capable of realizing the above functions. The following will be illustrated through multiple embodiments.

[0054] Based on this, the present application embodiment provides a multi-machine frequency response analysis method, referring to Figure 1 , Figure 1 The flowchart of the first embodiment of the multi-machine frequency response analysis method of the present application is shown in the figure.

[0055] In the embodiment, the multi-machine frequency response analysis method includes steps S100-S200:

[0056] In step S100, a preset disturbance power is input into a multi-machine frequency response model of a target multi-machine grid-connected system to obtain a grid frequency variation of the target multi-machine grid-connected system; wherein the multi-machine frequency response model is constructed based on a first equivalent frequency response model of a phase-modulator cluster accessing a grid and a second equivalent frequency response model of an enhanced SVG accessing the grid, and is configured to reflect a functional relationship between a disturbance power injected into the grid and the grid frequency variation, and the phase-modulator cluster includes a plurality of distributed phase-modulators.

[0057] In step S200, the frequency stability of the target multi-machine grid-connected system is analyzed based on the grid frequency variation.

[0058] Specifically, the above multi-machine grid-connected system refers to a power system in which the grid is simultaneously connected to an enhanced SVG and a plurality of distributed phase-modulators, and the enhanced SVG and the distributed phase-modulators cooperate to achieve power regulation and provide effective dynamic support for the grid.

[0059] In the frequency response analysis of the target multi-machine grid-connected system, a corresponding preset disturbance power can be determined for an actual possible active imbalance scenario of the grid (such as new energy output fluctuation, load mutation, etc.), and then the preset disturbance power is directly input into the pre-built multi-machine frequency response model to obtain the frequency response result (i.e. the grid frequency variation) corresponding to the disturbance power.

[0060] The above multi-machine frequency response model is fused from the first equivalent frequency response model of the phase-modulator cluster and the second equivalent frequency response model of the enhanced SVG. The first equivalent frequency response model is mainly used to represent the active response characteristics of the phase-modulator cluster to the grid frequency variation (i.e. the correlation between the active response power of the phase-modulator cluster and the grid frequency variation), and the second equivalent frequency response model is used to represent the active response characteristics of the enhanced SVG to the grid frequency variation (i.e. the correlation between the active response power of the enhanced SVG and the grid frequency variation).

[0061] The multi-machine frequency response model constructed on this basis is configured to reflect the functional relationship between the disturbance power injected into the grid and the grid frequency variation, which can ensure that the multi-machine frequency response model can output the real grid frequency variation that can reflect the cooperation of multiple machines after inputting the disturbance power. Thus, the abstract multi-machine frequency response process can be converted into a calculable quantitative result. In the frequency response analysis, the preset disturbance power is directly input into the multi-machine frequency response model to determine the corresponding grid frequency variation, and then the grid frequency variation under the preset disturbance power can be used to analyze the frequency stability of the target multi-machine grid-connected system.

[0062] The grid frequency variation is a direct quantitative embodiment of the frequency response capability, which can provide an objective basis for subsequent stability analysis, and according to the stability analysis result, an optimal control strategy for the target multi-machine grid-connected system can be quickly formulated, such as guiding the parameter optimization of each device in the system (such as adjusting the enhanced SVG control parameters, the capacity configuration of the distributed phase modifier, etc.), and ultimately improving the frequency response capability and dynamic power support effect of the grid.

[0063] In a feasible implementation, steps A100-A300 are further included before step S100, for uniformly constructing a multi-machine frequency response model of the multi-machine grid-connected system, as shown in Figure 2 Figure 2 The figure is a flow diagram of the multi-machine frequency response model construction in the multi-machine frequency response analysis method of the present application.

[0064] Step A100, a first equivalent frequency response model is constructed; wherein the first equivalent frequency response model is used to represent the active response characteristics of the phase modifier cluster to the grid frequency variation.

[0065] Specifically, the active response of multiple distributed phase modifiers in the phase modifier cluster can be focused on, and the active response power variation law of the phase modifier cluster when the grid frequency varies (such as how to increase the active power support when the frequency drops, etc.) is described. In a feasible implementation, step A100 can specifically include steps A110-A130, for aggregating the response characteristics of multiple distributed phase modifiers to obtain a first equivalent frequency response model that can represent the overall active response characteristics of the phase modifier cluster.

[0066] Step A110, the electrical parameters corresponding to each distributed phase modifier in the multi-machine grid-connected system are obtained; wherein the electrical parameters include equivalent inertia, equivalent damping coefficient, and equivalent reactance between the distributed phase modifier and the grid.

[0067] Step A120, the equivalent inertia, the equivalent damping coefficient, and the equivalent reactance of all distributed phase modifiers are weighted and averaged respectively with the phase modifier capacity of each distributed phase modifier as the weight, to obtain the aggregated equivalent inertia, the aggregated equivalent damping coefficient, and the aggregated equivalent reactance of the phase modifier cluster.

[0068] Step A130, the first equivalent frequency response model is constructed based on the aggregated equivalent inertia, the aggregated equivalent damping coefficient, and the aggregated equivalent reactance.

[0069] Suppose the phase modifier cluster has n distributed synchronous phase modifiers, for the 1 to n distributed phase modifiers, let the active response power output by the n distributed phase modifiers after injecting disturbance power correspond to , ​… ; on this basis, it can be determined that when only this n distributed phase modifier accesses the power grid, the power grid satisfies the disturbance-response mode:

[0070] (1)

[0071] wherein, H sys J is the equivalent inertia of the power grid, D sys D is the equivalent damping coefficient of the power grid, f g Δω is the frequency variation of the power grid, P d P is the disturbance power injected into the power grid, P sn P is the active response power corresponding to the n th distributed synchronous phase modifier, s s is the complex frequency (Laplace operator).

[0072] For each distributed synchronous phase modifier, let its number be i , ( i take 1~ n ) then its active power transmission (i.e. active response power) P si can be expressed as:

[0073] (2)

[0074] In the above formula, V i V is the terminal voltage of the i th distributed phase modifier, V g V is the voltage at the grid end, X i X is the equivalent reactance between the distributed phase modifier and the power grid, δ i θ is the phase angle variation of the i th distributed phase modifier, δ g θ is the phase angle variation of the power grid, .

[0075] Since there is no prime mover-governor, for the distributed phase modifier, its own phase angle variation δ iWith active response power P si The relationship satisfies the following equation:

[0076] (3)

[0077] In the formula, ω 0 is the rated angular frequency. H i For the first i The equivalent inertia of a distributed synchronous condenser D i For the first i The equivalent damping coefficient of a distributed synchronous condenser.

[0078] Combining equations (1) to (3) above, and... V i and V g All are approximately 1 p.u., which can determine only n The overall frequency response model of the grid-connected system after a distributed synchronous condenser is connected to the grid is as follows:

[0079] (4)

[0080] Figure 3 The frequency response control block diagram built based on the frequency response model shown in expression (4) above is as follows: Figure 3 As shown, each dashed box represents the equivalent frequency response model of a distributed synchronous condenser; in the figure, f i For the first i The frequency change of a distributed synchronous condenser.

[0081] To simplify the design of the model, this can be used. n The distributed synchronous condensers (SCPs) are aggregated to obtain a first equivalent frequency response model that characterizes the entire SCP cluster. The capacity of a distributed SCP directly represents its maximum active power output capability; generally, the larger the capacity of a distributed SCP, the more active power it can generate / decrease during grid frequency fluctuations, and the stronger its support / suppression effect on the grid frequency. Therefore, using the capacity of each distributed SCP as the weight, a weighted average can be performed on all equivalent inertia, equivalent damping coefficients, and equivalent reactances in the SCP cluster. This yields the aggregated equivalent inertia, aggregated equivalent damping coefficients, and aggregated equivalent reactances of the SCP cluster. Weighted averaging with capacity as the weight highlights the dominant role of large-capacity distributed SCPs, ensuring that the response characteristics of the subsequently constructed first equivalent frequency response model are consistent with the actual SCP cluster.

[0082] After aggregating the above distributed synchronous condensers, the above... n The overall frequency response model of a grid-connected system after a distributed synchronous condenser is connected to the grid can be equivalent to the following:

[0083] (5)

[0084] In equation (5), X eq for n The aggregated equivalent reactance of the distributed synchronous condensers H eq for n The aggregated equivalent inertia of a distributed synchronous condenser D eq for n The aggregated equivalent damping coefficient after aggregating the distributed synchronous condensers; the aggregation is performed using the synchronous condenser capacity of each distributed synchronous condenser as the weight, then... , , ;in, S i For the first i The capacity of each distributed synchronous condenser. If the capacity of each synchronous condenser in the synchronous condenser cluster is equal, then... .

[0085] According to equation (5), the following can be constructed: Figure 4 The diagram shown is a frequency response control block diagram of a grid-connected system after the aggregation of multiple distributed synchronous condensers. Figure 4 middle, f eq This refers to the frequency change of the aggregated distributed synchronous condenser. P seq This refers to the active response power of the aggregated distributed synchronous condensers (i.e., the active response power of the synchronous condenser cluster). For example... Figure 4 As shown, the dashed box represents the equivalent frequency response model of the aggregated distributed synchronous condensers, that is, the first equivalent frequency response model of the synchronous condenser cluster; the expression of this first equivalent frequency response model is:

[0086] (6)

[0087] in, P seq To adjust the active response power of the camera cluster, f g This represents the change in power grid frequency. ω 0 is the rated angular frequency. X eq For aggregate equivalent reactance,H eq For aggregated equivalent inertia, D eq This is the aggregate equivalent damping coefficient. s For the Laplace operator.

[0088] Step A200: Construct a second equivalent frequency response model; wherein, the second equivalent frequency response model is used to characterize the active power response characteristics of the enhanced SVG to changes in grid frequency.

[0089] For enhanced SVG, its active-frequency response characteristics can be characterized separately to clarify its active power regulation capability under frequency disturbances (i.e., the change law of the active power response of the enhanced SVG when the grid frequency changes). In a feasible implementation, step A200 may specifically include steps A210 to A240, used to determine a second equivalent frequency response model that can characterize its active power response characteristics based on the DC voltage self-synchronization control strategy of the enhanced SVG.

[0090] Step A210: Based on the DC voltage self-synchronization control principle of the enhanced SVG, determine the first correlation between the reference phase angle change of the enhanced SVG and the DC voltage change.

[0091] Step A220: Based on the DC capacitance characteristics of the enhanced SVG, determine the second correlation between the DC voltage change of the enhanced SVG and the active power response of the enhanced SVG.

[0092] Step A230: Based on the grid-connected line parameters of the enhanced SVG, determine the third correlation between the phase angle change of the enhanced SVG and the active power response of the enhanced SVG; the grid-connected line parameters include the virtual inductance, the filter inductance, and the equivalent impedance between the enhanced SVG and the grid.

[0093] Step A240: Based on the first association relationship, the second association relationship, and the third association relationship, construct the second equivalent frequency response model.

[0094] Specifically, in the control of enhanced SVG, a DC voltage self-synchronization method is often used. The phase angle of the enhanced SVG is calculated by the change in its DC voltage, and then combined with virtual impedance compensation to generate the three-phase self-synchronization voltage of the enhanced SVG. Thus, the primary correlation between the change in the reference phase angle of the enhanced SVG and the change in its DC voltage can be determined through the DC voltage self-synchronization control principle of the enhanced SVG.

[0095] Figure 5 An enhanced SVG control strategy and grid connection diagram are shown below. Figure 5 As shown, the DC voltage of the enhanced SVG Udc and the active power exchanged between the enhanced SVG and the power grid in real time P e The reference phase angle of the enhanced SVG is obtained through the DC voltage self-synchronization control module δ ref The voltage at the grid end V g and the reactive power exchanged between the enhanced SVG and the power grid in real time Q e The reference amplitude of the enhanced SVG output voltage is obtained through the AC voltage droop control module V ref ; δ ref and V ref The d-axis reference component of the output current of the enhanced SVG is obtained through the virtual impedance control module i dref and the q-axis reference component i qref ; i dref , i qref and the d-axis component of the actual voltage at the output side of the enhanced SVG v poid and the q-axis component v poiq are input to the current inner loop for reference control to obtain the d-axis reference component and the q-axis reference component of the enhanced SVG output voltage v odref ; v oqref . v odref , v oqref and δ ref After passing through the coordinate transformation module (abc / dq), v odref and v oqref are converted into three-phase AC voltage reference signals, and the three-phase AC voltage reference signals after coordinate transformation are input to the PWM module to generate pulse signals that can drive the thyristors inside the enhanced SVG. Figure 5 In the formula, Z f is the filter impedance, M is the grid connection point, Z L is the equivalent impedance between the enhanced SVG and the power grid, and G represents the power grid.

[0096] According to the DC voltage self-synchronization control of the enhanced SVG, its reference phase angle can be determinedδ ref The expression of the reference angle frequency of the enhanced SVG is:

[0097] (7)

[0098] In formula (7), ω ref is the reference angle frequency of the enhanced SVG, k P is the control proportional coefficient of the DC voltage self-synchronization control, k D is the control differential coefficient of the DC voltage self-synchronization control, T f is the inertia time constant of the DC voltage self-synchronization control, U dc is the DC voltage of the enhanced SVG, U dcref is the reference value of the DC voltage of the enhanced SVG.

[0099] Therefore, when the grid-connected system of the enhanced SVG occurs frequency disturbance, the reference phase angle change amount of the enhanced SVG δ ref and the DC voltage change amount ( U dc 2 ） satisfy the following formula:

[0100] (8)

[0101] According to the DC capacitor characteristics of the enhanced SVG, the DC side of the enhanced SVG can store electric energy through the capacitor C ; the capacitor current I dc can be expressed as: , and the capacitor current and the active power of the enhanced SVG P e can be expressed as: . That is, the DC voltage change is related to the active power of the enhanced SVG; thus, the second correlation between the DC voltage change amount and the active response power of the enhanced SVG can be obtained:

[0102] (9)

[0103] wherein, C dc is the DC capacitor value of the enhanced SVG, P eThe active response power of the enhanced SVG.

[0104] In addition, according to the active power transmission relationship of the line, the active response power of the enhanced SVG is also related to the reactance impedance on the grid-connected line of the enhanced SVG, and the virtual reactance of the enhanced SVG, the filter reactance, and the equivalent impedance of the grid-connected line jointly constitute the total equivalent reactance, which determines the active power transmission efficiency of the enhanced SVG. In an alternating current circuit, the active power transmission between two synchronous devices is proportional to the product of voltage and inversely proportional to the reactance, and the actual active response depends on the phase angle difference. Therefore, according to the grid-connected line parameters of the enhanced SVG, a third correlation between the phase angle change of the enhanced SVG and the active response power of the enhanced SVG can be determined:

[0105] (10)

[0106] wherein, V g is the grid voltage value, V ref is the voltage reference value of the enhanced SVG, X V is the virtual inductance of the enhanced SVG, X f is the filter inductance of the enhanced SVG, Z L is the equivalent impedance between the enhanced SVG and the grid, δ ref is the reference phase angle change of the enhanced SVG, δ g is the grid phase angle change, .

[0107] Therefore, according to the first correlation, the second correlation and the third correlation, a second equivalent frequency response model for characterizing the active response characteristics of the enhanced SVG to the grid frequency change can be constructed. That is, by combining the above formulas (8)-(10), the expression of the second equivalent frequency response model can be obtained as follows:

[0108] (11)

[0109] In formula (11), P e is the active response power of the enhanced SVG, f g is the grid frequency change, ω 0 is the rated angular frequency, X Va virtual inductance for the enhanced SVG, X f a filter inductance for the enhanced SVG, Z L an equivalent impedance between the enhanced SVG and the power grid, V ref a voltage reference value for the enhanced SVG, V g a power grid voltage value, C dc a DC capacitance value for the enhanced SVG, k P a control proportional coefficient for DC voltage self-synchronization control, k D a control differential coefficient for DC voltage self-synchronization control, T f an inertia time constant for DC voltage self-synchronization control, s a Laplace operator.

[0110] Step A300, constructing a multi-machine frequency response model corresponding to the multi-machine grid-connected system after the enhanced SVG and the cluster of phase-modulating machines are grid-connected, based on the first equivalent frequency response model and the second equivalent frequency response model.

[0111] After the first equivalent frequency response model of the cluster of phase-modulating machines and the second equivalent frequency response model of the enhanced SVG are determined, a multi-machine frequency response model of the multi-machine grid-connected system after the enhanced SVG and the cluster of phase-modulating machines are simultaneously grid-connected can be constructed based thereon. Specifically, the disturbance response multi-machine dynamic equation of the multi-machine grid-connected system obtained after the first equivalent frequency response model and the second equivalent frequency response model are combined in the same power grid can be expressed as:

[0112] (12)

[0113] wherein, H sys an equivalent inertia of the power grid, D sys an equivalent damping coefficient of the power grid, f g a power grid frequency variation, P d a disturbance power injected into the power grid, P seq an active response power of the cluster of phase-modulating machines, P e an active response power of the enhanced SVG.

[0114] The expression (6) of the first equivalent frequency response model and the expression (11) of the second equivalent frequency response model are substituted into the above formula (12), and are arranged into an expression (i.e., an expression of a multi-machine frequency response model) that can directly reflect the relationship between the disturbance power injected into the power grid and the change amount of the power grid frequency:

[0115] (13)

[0116] As shown in Figure 6 , Figure 6 is a frequency response control block diagram built based on the multi-machine dynamic equation of the disturbance response of the multi-machine grid-connected system obtained after the above-mentioned cluster of phase-modulating machines and the enhanced SVG are connected to the grid.

[0117] After the above-mentioned multi-machine frequency response model is constructed, for any disturbance power injected into the power grid, the change amount of the power grid frequency can be directly solved according to the expression (13) to guide the subsequent parameter optimization and the formulation of the real-time control strategy of the grid-connected system, and the efficiency of the power grid frequency analysis can be effectively improved.

[0118] It can be understood that the multi-machine frequency response analysis method provided in the embodiments of the present application can directly input a preset disturbance power into a multi-machine frequency response model of a target multi-machine grid-connected system to be analyzed when performing frequency response analysis on the multi-machine grid-connected system composed of the enhanced SVG and the plurality of distributed phase-modulating machines. The multi-machine frequency response model is constructed based on the first equivalent frequency response model of the cluster of phase-modulating machines connected to the power grid and the second equivalent frequency response model of the enhanced SVG connected to the power grid. The above-mentioned two equivalent frequency response models are integrated into a unified multi-machine frequency response model, which accurately corresponds to the multi-machine grid-connected scenario of the enhanced SVG and the distributed phase-modulating machines. The multi-machine frequency response model is configured to reflect the functional relationship between the disturbance power injected into the power grid and the change amount of the power grid frequency. By inputting the preset disturbance power (simulating the active disturbance in the actual power grid), the change amount of the power grid frequency corresponding to the disturbance power can be directly obtained. The change amount of the power grid frequency is a core quantitative index of the frequency response capability. Therefore, the frequency stability of the target multi-machine grid-connected system can be quickly and accurately analyzed based on the change amount of the power grid frequency, and a decision basis is provided for subsequent optimization control.

[0119] Exemplarily, in order to help understand the implementation process of the multi-machine frequency response analysis method in the first embodiment, please refer to Figure 7 , Figure 7 A brief flowchart of multi-machine frequency response model construction in a multi-machine frequency response analysis method is provided, and specifically:

[0120] Firstly, multiple distributed phase modulators can be equivalent to an aggregated unit, and an overall frequency response model of a grid-connected system in which multiple distributed phase modulators are aggregated and connected to a power grid can be established (see the content of expression (5) and Figure 4 expression (6) in the foregoing embodiments). According to the overall frequency response model, a first equivalent frequency response model of a phase modulator cluster corresponding to the multiple distributed phase modulators can be determined as shown in expression (6).

[0121] Then, a second equivalent frequency response model of the enhanced SVG connected to the power grid can be established based on a control link of the enhanced SVG. Specifically, the second equivalent frequency response model of the enhanced SVG can be established based on direct-current voltage self-synchronization control, direct-current capacitor characteristics, and active power transmission of a grid-connected line, as described in the foregoing embodiments.

[0122] Subsequently, a disturbance-response multi-machine dynamic equation of the enhanced SVG and the multiple distributed phase modulators connected to the power grid can be constructed as shown in expression (12).

[0123] Finally, the first equivalent frequency response model and the second equivalent frequency response model are substituted into the disturbance-response multi-machine dynamic equation of the enhanced SVG and the multiple distributed phase modulators connected to the power grid, to derive a multi-machine frequency response model of the enhanced SVG and the phase modulator cluster and a closed-form solution thereof, i.e., Figure 6 as shown in expression (13).

[0124] By introducing a direct-current voltage self-synchronization mechanism and aggregated modeling of multiple distributed phase modulators, the accuracy of the multi-machine frequency response model of the enhanced SVG and the distributed phase modulators in a multi-machine system can be significantly improved. The multi-machine frequency response model can systematically describe the dynamic characteristics of the enhanced SVG and the phase modulator cluster formed by the multiple distributed phase modulators, accurately capture the interaction and cluster effect between devices, and provide a closed-form solution that facilitates subsequent device parameter optimization and real-time control strategy formulation. Compared with related technologies, the method of the present application enhances the analysis efficiency of power grid frequency stability, is suitable for high-penetration renewable energy scenarios, and can effectively reduce the frequency fluctuation risk through fast frequency analysis. The above method can also be extended to other types of power electronic devices according to actual conditions, to improve the robustness and reliability of the overall power grid.

[0125] It should be noted that the above examples are only used to understand the present application and do not limit the multi-machine frequency response analysis method of the present application. Further simple transformations based on this technical concept are within the scope of protection of the present application.

[0126] The present application also provides a multi-machine frequency response analysis device, which can be referred to as Figure 8 The multi-machine frequency response analysis device comprises:

[0127] The disturbance input module 10 is configured to input a preset disturbance power into a multi-machine frequency response model of the target multi-machine grid-connected system to obtain a grid frequency variation of the target multi-machine grid-connected system. The multi-machine frequency response model is constructed based on a first equivalent frequency response model of a cluster of phase-modulated machines connected to the grid and a second equivalent frequency response model of an enhanced SVG connected to the grid, and is configured to reflect a functional relationship between the disturbance power injected into the grid and the grid frequency variation. The cluster of phase-modulated machines includes a plurality of distributed phase-modulated machines.

[0128] The frequency analysis module 20 is configured to analyze the frequency stability of the target multi-machine grid-connected system based on the grid frequency variation.

[0129] The multi-machine frequency response analysis device provided in the present application adopts the multi-machine frequency response analysis method in the above embodiments, and can solve the technical problem that related technologies lack systematic analysis of the active-frequency response of the multi-machine grid-connected scenario of the enhanced SVG and the distributed phase-modulated machine. Compared with related technologies, the multi-machine frequency response analysis device provided in the present application has the same beneficial effects as the multi-machine frequency response analysis method provided in the above embodiments, and other technical features in the multi-machine frequency response analysis device are the same as the features disclosed in the above embodiments, which will not be repeated here.

[0130] The present application provides a multi-machine frequency response analysis device, which includes at least one processor and a memory in communication connection with the at least one processor. The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the multi-machine frequency response analysis method in Embodiment I.

[0131] Reference will now be made to the following description Figure 9 which shows a structural schematic diagram of a multi-machine frequency response analysis device suitable for implementing the embodiments of the present application. The multi-machine frequency response analysis device in the embodiments of the present application can include, but is not limited to, mobile terminals such as notebook computers, PADs (Portable Application Description: tablet computers), and the like, and fixed terminals such as desktop computers, and the like. Figure 9 The multi-machine frequency response analysis device shown is only an example, and should not impose any limitation on the functions and use range of the embodiments of the present application.

[0132] As Figure 9As shown, the multi-machine frequency response analysis device can include a processing device 1001 (e.g., a central processing unit, a graphics processing unit, etc.) that can perform various appropriate actions and processes according to programs stored in a read-only memory (ROM) 1002 or programs loaded from a storage device 1003 into a random access memory (RAM) 1004. Various programs and data required for operation of the multi-machine frequency response analysis device are also stored in the RAM 1004. The processing device 1001, the read-only memory 1002, and the random access memory 1004 are connected to each other by a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems can be connected to the input / output interface 1006: an input device 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, etc.; an output device 1008 including, for example, a liquid crystal display (LCD), etc.; the storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the multi-machine frequency response analysis device to communicate wirelessly or by wire with other devices to exchange data. Although the multi-machine frequency response analysis device with various systems is shown in the figure, it should be understood that all the systems shown are not required to be implemented or possessed. More or fewer systems can be alternatively implemented or possessed.

[0133] In particular, according to embodiments of the present disclosure, the processes described above with reference to the flowcharts can be implemented as a computer software program. For example, embodiments of the present disclosure include a computer program product comprising a computer program carried on a computer readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network by a communication device, or installed from the storage device 1003, or installed from the read-only memory 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the methods of the embodiments of the present disclosure are performed.

[0134] The multi-machine frequency response analysis device provided by the present disclosure adopts the multi-machine frequency response analysis method in the above embodiments, and can solve the technical problem in the related art that there is a lack of systematic analysis method for active-frequency response of the multi-machine grid-connected scene of the enhanced SVG and the distributed phase modifier. Compared with the related art, the multi-machine frequency response analysis device provided by the present disclosure has the same beneficial effects as the multi-machine frequency response analysis method provided by the above embodiments, and other technical features in the multi-machine frequency response analysis device are the same as the features disclosed in the previous embodiment method, which will not be repeated here.

[0135] It should be understood that various aspects of the disclosure can be implemented in hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any appropriate manner in any one or more embodiments or examples.

[0136] The above description is merely illustrative of the application and is not intended to limit the scope of the application. Any variations and modifications that can be made by any person skilled in the art within the spirit and scope of the application are intended to be encompassed by the application. The scope of the application is defined by the appended claims.

[0137] The application provides a computer readable storage medium having stored thereon computer readable program instructions (i.e., a computer program) for performing the multi-machine frequency response analysis method in the above embodiments.

[0138] The computer readable storage medium provided by the application may, for example, be a U disk, but is not limited to an electric, magnetic, optical, electromagnetic, infrared, or semiconductor system or device, or any combination thereof. More specific examples of the computer readable storage medium can include, but are not limited to, an electric connection having one or more conductive wires, a portable computer disk, a hard disk, a random access memory (RAM), a read only memory (ROM), an erasable programmable read only memory (EPROM or flash memory), an optical fiber, a portable compact disk read only memory (CD-ROM), an optical storage device, a magnetic storage device, or any appropriate combination thereof. In the present embodiment, the computer readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system or device. The program code contained on the computer readable storage medium can be transmitted by any appropriate medium, including but not limited to an electric wire, an optical cable, an RF (Radio Frequency), etc., or any appropriate combination thereof.

[0139] The above computer readable storage medium can be contained in the multi-machine frequency response analysis device; or can exist separately and not be assembled into the multi-machine frequency response analysis device.

[0140] The computer readable storage medium described above carries one or more programs, when the one or more programs are executed by the multi-machine frequency response analysis device, the multi-machine frequency response analysis device is caused to: input a preset disturbance power into a multi-machine frequency response model of a target multi-machine grid-connected system, and obtain a power grid frequency change amount of the target multi-machine grid-connected system; wherein the multi-machine frequency response model is constructed based on a first equivalent frequency response model of a phase modifier cluster accessing a power grid and a second equivalent frequency response model of an enhanced SVG accessing the power grid, and is configured to reflect a functional relationship between a disturbance power injected into the power grid and the power grid frequency change amount, and the phase modifier cluster includes a plurality of distributed phase modifiers; and analyze frequency stability of the target multi-machine grid-connected system based on the power grid frequency change amount.

[0141] Computer program code for carrying out operations of the present application can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0142] The flow diagrams and the block diagrams in the drawings are illustrations of architectures, functionalities, and operations of possible implementations of systems, methods, and computer program products according to various embodiments of present application. In this regard, each block in the flow diagrams or block diagrams can represent a module, a segment, or a portion of code, which comprises one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently or the blocks may

[0143] The modules described in the embodiments of the present application can be implemented in the form of software or in the form of hardware. In some cases, the name of the module does not constitute a limitation on the module itself.

[0144] The readable storage medium provided in the present application is a computer readable storage medium, which stores computer readable program instructions (i.e., a computer program) for executing the multi-machine frequency response analysis method described above, and can solve the technical problem of lack of a systematic analysis method for the active-frequency response of the multi-machine grid-connection scenario of the enhanced SVG and the distributed phase modifier. Compared with the related art, the computer readable storage medium provided in the present application has the same beneficial effects as the multi-machine frequency response analysis method provided in the above embodiments, and will not be described here.

[0145] The present application also provides a computer program product, which includes a computer program, and the computer program, when executed by a processor, implements the steps of the multi-machine frequency response analysis method described above.

[0146] The computer program product provided in the present application can solve the technical problem of lack of a systematic analysis method for the active-frequency response of the multi-machine grid-connection scenario of the enhanced SVG and the distributed phase modifier. Compared with the related art, the computer program product provided in the present application has the same beneficial effects as the multi-machine frequency response analysis method provided in the above embodiments, and will not be described here.

[0147] The above only describes some embodiments of the present application, and does not limit the protection scope, and any equivalent structural transformation, direct / indirect application in other related technical fields based on the technical concept of the present application, and the content of the specification and drawings are included in the protection scope.

Claims

1. A method for analyzing the frequency response of multiple machines, characterized in that, The multi-machine frequency response analysis method includes: A preset disturbance power is input into the multi-machine frequency response model of the target multi-machine grid-connected system to obtain the grid frequency change of the target multi-machine grid-connected system; wherein, the multi-machine frequency response model is constructed based on the first equivalent frequency response model of the synchronous condenser cluster connected to the grid and the second equivalent frequency response model of the enhanced SVG connected to the grid, and is configured to reflect the functional relationship between the disturbance power injected into the grid and the grid frequency change; the synchronous condenser cluster includes multiple distributed synchronous condensers; The expression for the first equivalent frequency response model is: in, P seq The active response power of the synchronous condenser cluster. f g This represents the change in power grid frequency. ω 0 is the rated angular frequency. X eq For aggregate equivalent reactance, H eq For aggregated equivalent inertia, D eq The equivalent damping coefficient is the polymeric damping coefficient. s For the Laplace operator; Based on the power grid frequency change, the frequency stability of the target multi-machine grid-connected system is analyzed.

2. The multi-machine frequency response analysis method as described in claim 1, characterized in that, Before the step of inputting a preset disturbance power into the multi-machine frequency response model of the target multi-machine grid-connected system to obtain the grid frequency change of the target multi-machine grid-connected system, the method further includes: Construct the first equivalent frequency response model; wherein, the first equivalent frequency response model is used to characterize the active power response characteristics of the synchronous condenser cluster to changes in grid frequency; Construct the second equivalent frequency response model; wherein, the second equivalent frequency response model is used to characterize the active power response characteristics of the enhanced SVG to changes in grid frequency; Based on the first equivalent frequency response model and the second equivalent frequency response model, a multi-machine frequency response model is constructed corresponding to the multi-machine grid-connected system after the enhanced SVG and the synchronous condenser cluster are connected to the grid.

3. The multi-machine frequency response analysis method as described in claim 2, characterized in that, The steps for constructing the first equivalent frequency response model include: Obtain the electrical parameters corresponding to each of the distributed synchronous condensers in the multi-machine grid-connected system; wherein, the electrical parameters include equivalent inertia, equivalent damping coefficient, and equivalent reactance between the distributed synchronous condenser and the power grid; Using the capacity of each of the distributed synchronous condensers as the weight, a weighted average is performed on all the equivalent inertia, equivalent damping coefficients, and equivalent reactances to obtain the aggregated equivalent inertia, aggregated equivalent damping coefficients, and aggregated equivalent reactances of the synchronous condenser cluster. Based on the aggregated equivalent inertia, the aggregated equivalent damping coefficient, and the aggregated equivalent reactance, the first equivalent frequency response model is constructed.

4. The multi-machine frequency response analysis method as described in claim 2, characterized in that, The steps for constructing the second equivalent frequency response model include: Based on the DC voltage self-synchronization control principle of the enhanced SVG, the first correlation relationship between the reference phase angle change of the enhanced SVG and the DC voltage change is determined; Based on the DC capacitance characteristics of the enhanced SVG, a second correlation relationship is determined between the DC voltage change of the enhanced SVG and the active power response of the enhanced SVG. Based on the grid-connected line parameters of the enhanced SVG, a third correlation relationship is determined between the phase angle change of the enhanced SVG and the active power response of the enhanced SVG; the grid-connected line parameters include virtual inductance, filter inductance, and equivalent impedance between the enhanced SVG and the grid; Based on the first association, the second association, and the third association, the second equivalent frequency response model is constructed.

5. The multi-machine frequency response analysis method as described in claim 4, characterized in that, The expression for the second equivalent frequency response model is: in, P e The active response power of the enhanced SVG, f g This represents the change in power grid frequency. ω 0 is the rated angular frequency. X V For enhanced SVG virtual inductance, X f For the filter inductor of the enhanced SVG, Z L To provide the equivalent impedance between the enhanced SVG and the power grid, V ref For the voltage reference value of the enhanced SVG, V g This is the grid voltage value. C dc For the DC capacitance value of the enhanced SVG, k P This is the control proportional coefficient for DC voltage self-synchronization control. k D These are the control differential coefficients for DC voltage self-synchronization control. T f The inertial time constant for DC voltage self-synchronization control. s For the Laplace operator.

6. A multi-machine frequency response analysis device, characterized in that, The multi-machine frequency response analysis device includes: The disturbance input module is used to input a preset disturbance power into the multi-machine frequency response model of the target multi-machine grid-connected system to obtain the grid frequency change of the target multi-machine grid-connected system; wherein, the multi-machine frequency response model is constructed based on the first equivalent frequency response model of the synchronous condenser cluster connected to the grid and the second equivalent frequency response model of the enhanced SVG connected to the grid, and is configured to reflect the functional relationship between the disturbance power injected into the grid and the grid frequency change; the synchronous condenser cluster includes multiple distributed synchronous condensers. The expression for the first equivalent frequency response model is: in, P seq The active response power of the synchronous condenser cluster. f g This represents the change in power grid frequency. ω 0 is the rated angular frequency. X eq For aggregate equivalent reactance, H eq For aggregated equivalent inertia, D eq The equivalent damping coefficient is the polymeric damping coefficient. s For the Laplace operator; The frequency analysis module is used to analyze the frequency stability of the target multi-machine grid-connected system based on the changes in the grid frequency.

7. A multi-machine frequency response analysis device, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the multi-machine frequency response analysis method as described in any one of claims 1 to 5.

8. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the multi-machine frequency response analysis method as described in any one of claims 1 to 5.

9. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the steps of the multi-machine frequency response analysis method as described in any one of claims 1 to 5.

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