A new energy station network unit optimization configuration method and device

Abstract

The present invention relates to a method and device for optimizing the configuration of grid-connected units of a new energy station, comprising: calculating a wide-band oscillation stability margin index of the new energy station grid-connected system using relevant parameters of the new energy station grid-connected system; judging whether the new energy station grid-connected system needs to be optimized based on the wide-band oscillation stability margin index; when the new energy station grid-connected system needs to be optimized, calculating a participation factor of each converter access node within the new energy station grid-connected system using a node impedance model of the new energy station grid-connected system; optimizing the configuration of the grid-connected units of the new energy station grid-connected system based on the participation factors of each converter access node within the new energy station grid-connected system, and recalculating the wide-band oscillation stability margin index of the new energy station grid-connected system until the new energy station grid-connected system reaches the optimal configuration. The present invention achieves reasonable configuration of the capacity and position of the grid-connected units while ensuring the wide-band oscillation stability margin of the grid-connected system.

Description

Technical Field

[0001] The present invention belongs to the technical field of renewable energy power generation, and in particular relates to a method and device for optimizing the configuration of grid-type units of renewable energy stations. Background Art

[0002] Wind and solar resources are distributed inversely with load centers, and concentrated development and long-distance transmission are important forms of new energy development and utilization. The key characteristics of new energy bases are their distance from the AC main grid, the lack of conventional synchronous power support, and a relatively weak power grid, leading to prominent system safety and stability issues. Research and analysis have shown that the characteristics of new energy power generation devices and their interaction with weakly synchronized power grids are the main causes of these problems. Currently, mainstream wind and solar power generation uses phase-locked control to follow the synchronous voltage of the grid, and uses multi-loop control to achieve power conversion and maximum power tracking output. Under normal operating conditions, the wide-band dynamics of the multi-loop control of the new energy power generation converter interact with the impedance characteristics of the weak grid, causing dynamic stability problems in the subsynchronous to supersynchronous frequency range, and instability manifests as oscillation.

[0003] Improving renewable energy generation's ability to adapt to or support weak grids, starting from the renewable energy generation control side, has become a direct means of addressing these issues. Renewable energy generation grid-connected control technology synchronizes with the grid through a self-synchronizing control algorithm, generating its own internal potential. It has the ability to independently establish and adjust frequency and voltage, enabling grid-connected operation independent of genlock. This technology can effectively support stable system operation in weak grids, and has therefore garnered widespread attention and research in recent years.

[0004] However, under the large-scale, continuous, and rapid development model of new energy, a large number of already built and operational new energy stations need to undergo transformation and upgrades of grid-forming technologies to improve stable operation and transmission capacity under weak power grids, while also providing room for improvement in stability margin for subsequent grid connection of new stations. However, due to differences in control principles, new energy power generation units using grid-forming control strategies have difficulty maintaining maximum power point tracking control, which affects the efficiency of new energy consumption. Therefore, how to reasonably configure the capacity and layout of the grid-forming units of new energy stations, while ensuring the system's broadband oscillation stability margin, while minimizing the capacity of the grid-forming units, has become a key issue in engineering applications.

[0005] Wang Yining et al. published an analysis of the optimal proportions of grid-connected direct-drive wind turbines, proposing an analysis based on the equivalent short-circuit ratio. However, this method has the following drawbacks: the stability of the grid-connected system cannot be simply evaluated based on the system's short-circuit capacity; and the aggregated wind farm equivalent model ignores the impact of the wind farm's internal network topology on system stability, which is inconsistent with actual engineering applications.

[0006] Yu Guangzheng published research on the coordinated optimization configuration method for hybrid multi-feed systems with grid-following / grid-forming types, proposing a coordinated optimization configuration method for grid-following / grid-forming types based on modal decoupling. However, this method has the following shortcomings: the optimization configuration method proposed for heterogeneous hybrid multi-feed systems simplifies device types within multiple frequency bands, and the stability analysis results are equivalent to those of homogeneous multi-feed systems, which is inconsistent with actual engineering application scenarios. Summary of the Invention

[0007] In order to overcome the problems existing in the above-mentioned related technologies, the present application provides a method and device for optimizing the configuration of grid-type units of new energy stations.

[0008] According to a first aspect of an embodiment of the present application, a method for optimizing configuration of a new energy station network unit is provided, comprising:

[0009] Collect relevant parameters of the new energy station grid connection system;

[0010] Utilizing the relevant parameters of the new energy station grid-connected system, a wide-band oscillation stability margin index of the new energy station grid-connected system is calculated;

[0011] According to the broadband oscillation stability margin index of the new energy station grid connection, determine whether the new energy station grid connection system needs to be optimized;

[0012] When the grid-connected system of a new energy station needs to be optimized, the node impedance model of the grid-connected system of the new energy station is used to calculate the participation factor of each converter access node in the grid-connected system of the new energy station;

[0013] According to the participation factors of the converter access nodes in the new energy station grid-connected system, the grid-type unit of the new energy station grid-connected system is optimized and the broadband oscillation stability margin index of the new energy station grid-connected system is recalculated until the new energy station grid-connected system reaches the optimal configuration.

[0014] Preferably, the relevant parameters of the new energy station grid-connected system include: operating point parameters of the new energy station grid-connected system, network topology parameters of the new energy station grid-connected system and control parameters of the new energy power generation unit;

[0015] The operating point parameters of the new energy station grid-connected system include: voltage signals and current signals of each node in the new energy station grid-connected system;

[0016] The network topology parameters of the new energy station grid-connected system include: a node admittance matrix of the new energy station grid-connected system;

[0017] The control parameters of the new energy power generation unit include: main circuit parameters and control parameters of the new energy power generation unit;

[0018] The main circuit parameters include: rated capacity and rated voltage of the converter, filter inductance and filter capacitance in the converter main circuit;

[0019] The control parameters include: control parameters of the power link, voltage link, current link and virtual impedance used in the converter controller.

[0020] Preferably, the calculation of the wide-band oscillation stability margin index of the new energy station grid connection by using relevant parameters of the new energy station grid connection system includes:

[0021] Based on the relevant parameters of the new energy station grid-connected system, the impedance ratio of the new energy station grid-connected system is calculated using a pre-built new energy side aggregate impedance model;

[0022] Calculating a stability margin function of the new energy station grid-connected system using the impedance ratio of the new energy station grid-connected system;

[0023] The wide-band oscillation stability margin index of the new energy station grid-connected system is calculated using the new energy station grid-connected system stability margin function.

[0024] Preferably, the calculation formula of the new energy side aggregation impedance model includes:

[0025]

[0026] The calculation formula for the grid-connected system impedance ratio of the new energy station includes:

[0027]

[0028] In the above formula, is the aggregate admittance of the new energy station, is the aggregate impedance of the new energy station, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the grid connection point of the new energy station. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the grid connection point of the new energy station. is the negative sequence admittance on the grid side, is the negative sequence admittance of the new energy station, s is the pull operator, s′ is the coupling frequency pull-down operator, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, Z g (s) is the positive sequence impedance on the grid side.

[0029] Preferably, the calculation formula of the new energy station grid-connected system stability margin function includes:

[0030] G(s)=1+Z ratio (s)

[0031] In the above formula, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, G(s) is the stability margin function of the grid-connected system of new energy stations, and s is a pull operator.

[0032] Preferably, the calculation formula for the broadband oscillation stability margin index of the new energy station grid connection includes:

[0033]

[0034] In the above formula, γ It is the broadband oscillation stability margin index for new energy stations connected to the grid. s = jω , G(jω) is the stability margin function of the grid-connected system of new energy stations, j is the imaginary number symbol, ω is the angular frequency.

[0035] Preferably, judging whether the grid-connected system of the new energy station needs to be optimized according to the grid-connected broadband oscillation stability margin index of the new energy station includes:

[0036] Determine whether the broadband oscillation stability margin index of the new energy station grid-connected is greater than or equal to the margin threshold. If the broadband oscillation stability margin index of the new energy station grid-connected is greater than or equal to the margin threshold, the new energy station grid-connected system does not need to be optimized, and the current configuration of the new energy station grid-connected system is the optimal configuration; if the broadband oscillation stability margin index of the new energy station grid-connected is less than the margin threshold, the new energy station grid-connected system needs to be optimized.

[0037] Preferably, when the new energy station grid-connected system needs to be optimized, the node impedance model of the new energy station grid-connected system is used to calculate the participation factor of each converter access node in the new energy station grid-connected system, including:

[0038] According to the node impedance model of the new energy station grid-connected system, a characteristic equation of the node impedance model of the new energy station grid-connected system is obtained;

[0039] The characteristic equation of the node impedance model of the new energy station grid-connected system is used to obtain the participation factor of each converter access node in the new energy station grid-connected system.

[0040] Preferably, the obtaining of the characteristic equation of the node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system includes:

[0041] Determining a denominator of a closed-loop transfer function of the node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system;

[0042] The denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system is set to zero, and the characteristic equation of the node impedance model of the new energy station grid-connected system is obtained by simplification.

[0043] Preferably, the method of using the characteristic equation of the node impedance model of the new energy station grid-connected system to obtain the participation factor of each converter access node in the new energy station grid-connected system includes:

[0044] Using Schur complement transformation, the characteristic equation of the node impedance model of the new energy station grid-connected system is transformed into the solution of the determinant of the n+1 dimensional ordered impedance matrix to obtain the model eigenvalue;

[0045] Determining stability information and oscillation property information of the new energy station grid-connected system according to the model characteristic value;

[0046] When the new energy station grid-connected system is unstable, the participation factor of each converter access node in the new energy station grid-connected system under the oscillation mode is calculated according to the oscillation mode corresponding to the model eigenvalue.

[0047] Preferably, the calculation formula of the node impedance model of the new energy station grid-connected system includes:

[0048]

[0049] In the above formula, s is the pull-type operator, s′ is the coupling frequency pull-down operator, is the n+1-dimensional positive sequence small signal current component, is the n+1-dimensional negative sequence small signal current component, is the positive sequence node admittance matrix of the network element, is the negative-sequence node admittance matrix of the network elements, is the positive sequence admittance diagonal matrix of the converter, is a diagonal matrix composed of the coupled admittances calculated from the negative sequence current disturbance component and the positive sequence voltage disturbance component at each node in the new energy station. is the diagonal matrix composed of the converter coupling admittance calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at each node in the new energy station. is the negative sequence admittance diagonal matrix of the converter, is the n+1-dimensional positive sequence small signal voltage component, It is the n+1-dimensional negative-sequence small signal voltage component.

[0050] Preferably, the calculation formula of the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system includes:

[0051]

[0052] The calculation formula of the characteristic equation of the node impedance model of the new energy station grid-connected system includes:

[0053]

[0054] In the above formula, s is the pull operator, det(・) is the determinant to be solved, Y net (s) is the 2(n+1)-dimensional admittance matrix of the network element, Y reg (s) is the 2(n+1)-dimensional admittance matrix of the converter.

[0055] Preferably, the calculation formula for solving the determinant of the n+1-dimensional ordered impedance matrix includes:

[0056]

[0057] The calculation formula of the model characteristic value includes:

[0058]

[0059] In the above formula, s is the pull operator, det(・) is the determinant to be solved, For Solve the determinant, is the corrected equivalent positive sequence admittance of the new energy station grid-connected system, L for The left eigenvector matrix of is the eigenvalue diagonal matrix, diag{·} is the diagonal matrix, λ n is the nth eigenvalue, λ n+1 is the n+1th eigenvalue, n+1 is the order of the matrix, T for The right eigenvector matrix of .

[0060] Preferably, the calculation formula for the participation factor of the converter access node in the new energy station grid-connected system includes:

[0061] p i=L ik •T ik

[0062] In the above formula, i is the converter access node in the new energy station grid-connected system, p i Connecting nodes to converters in new energy station grid-connected systems i The participation factor, T ik To reflect the converter access nodes in the new energy station grid-connected system i The injection current k The characteristic trajectory effect, L ik for T ik The corresponding weight of the new energy station grid-connected system mode.

[0063] Preferably, the step of optimizing the grid-connected unit configuration of the new energy station grid-connected system according to the participation factor of each converter access node in the new energy station grid-connected system includes:

[0064] From the participation factors of the converter access nodes in the new energy station grid-connected system, the grid-following converter connected to the node with the largest participation factor is selected and replaced with a grid-forming converter of the same capacity.

[0065] According to a second aspect of an embodiment of the present application, a device for optimizing the configuration of a networked unit of a new energy station is provided, comprising:

[0066] The acquisition unit is used to collect relevant parameters of the grid-connected system of the new energy station;

[0067] A first calculation unit is configured to calculate a wide-band oscillation stability margin index of the new energy station grid connection using relevant parameters of the new energy station grid connection system;

[0068] A judgment unit, configured to judge whether the grid-connected system of the new energy station needs to be optimized according to the broadband oscillation stability margin index of the grid-connected new energy station;

[0069] The second calculation unit is used to calculate the participation factor of each converter access node in the new energy station grid-connected system by using the node impedance model of the new energy station grid-connected system when the new energy station grid-connected system needs to be optimized;

[0070] The optimization configuration unit is used to optimize the configuration of the grid-connected units of the new energy station grid-connected system according to the participation factors of the converter access nodes in the new energy station grid-connected system, and recalculate the wide-band oscillation stability margin index of the new energy station grid-connected system until the new energy station grid-connected system reaches the optimal configuration.

[0071] Preferably, the relevant parameters of the new energy station grid-connected system include: operating point parameters of the new energy station grid-connected system, network topology parameters of the new energy station grid-connected system and control parameters of the new energy power generation unit;

[0072] The operating point parameters of the new energy station grid-connected system include: voltage signals and current signals of each node in the new energy station grid-connected system;

[0073] The network topology parameters of the new energy station grid-connected system include: a node admittance matrix of the new energy station grid-connected system;

[0074] The control parameters of the new energy power generation unit include: main circuit parameters and control parameters of the new energy power generation unit;

[0075] The main circuit parameters include: rated capacity and rated voltage of the converter, filter inductance and filter capacitance in the converter main circuit;

[0076] The control parameters include: control parameters of the power link, voltage link, current link and virtual impedance used in the converter controller.

[0077] Preferably, the first computing unit includes:

[0078] A first calculation module is configured to calculate the impedance ratio of the new energy station grid-connected system based on relevant parameters of the new energy station grid-connected system and using a pre-built new energy side aggregate impedance model;

[0079] A second calculation module is configured to calculate a stability margin function of the new energy station grid-connected system using the impedance ratio of the new energy station grid-connected system;

[0080] The third calculation module is used to calculate the wide-band oscillation stability margin index of the new energy station grid connection using the new energy station grid connection system stability margin function.

[0081] Preferably, the calculation formula of the new energy side aggregation impedance model includes:

[0082]

[0083] The calculation formula for the grid-connected system impedance ratio of the new energy station includes:

[0084]

[0085] In the above formula, is the aggregate admittance of the new energy station, is the aggregate impedance of the new energy station, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the grid connection point of the new energy station. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the grid connection point of the new energy station. is the negative sequence admittance on the grid side, is the negative sequence admittance of the new energy station, s is the pull operator, s′ is the coupling frequency pull-down operator, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, Z g (s) is the positive sequence impedance on the grid side.

[0086] Preferably, the calculation formula of the new energy station grid-connected system stability margin function includes:

[0087] G(s)=1+Z ratio (s)

[0088] In the above formula, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, G(s) is the stability margin function of the grid-connected system of new energy stations, and s is a pull operator.

[0089] Preferably, the calculation formula for the broadband oscillation stability margin index of the new energy station grid connection includes:

[0090]

[0091] In the above formula, γ It is the broadband oscillation stability margin index for new energy stations connected to the grid. s = jω , G(jω) is the stability margin function of the grid-connected system of new energy stations, j is the imaginary number symbol, ω is the angular frequency.

[0092] Preferably, the judgment unit is specifically used to:

[0093] Determine whether the broadband oscillation stability margin index of the new energy station grid-connected is greater than or equal to the margin threshold. If the broadband oscillation stability margin index of the new energy station grid-connected is greater than or equal to the margin threshold, the new energy station grid-connected system does not need to be optimized, and the current configuration of the new energy station grid-connected system is the optimal configuration; if the broadband oscillation stability margin index of the new energy station grid-connected is less than the margin threshold, the new energy station grid-connected system needs to be optimized.

[0094] Preferably, the second computing unit includes:

[0095] A first acquisition module is configured to acquire a characteristic equation of the node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system;

[0096] The second acquisition module is used to obtain the participation factor of each converter access node in the new energy station grid-connected system by using the characteristic equation of the node impedance model of the new energy station grid-connected system.

[0097] Preferably, the first acquisition module includes:

[0098] A first determining submodule is configured to determine a denominator of a closed-loop transfer function of a node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system;

[0099] The first acquisition submodule is used to make the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system equal to zero, and simplify to obtain the characteristic equation of the node impedance model of the new energy station grid-connected system.

[0100] Preferably, the second acquisition module includes:

[0101] The second acquisition submodule is used to convert the characteristic equation of the node impedance model of the new energy station grid-connected system into a solution for solving the determinant of the n+1 dimensional ordered impedance matrix using Schur complement transformation to obtain the model eigenvalue;

[0102] A second determining submodule is configured to determine stability information and oscillation property information of the new energy station grid-connected system according to the model characteristic value;

[0103] The calculation submodule is used to calculate the participation factor of each converter access node in the new energy station grid-connected system under the oscillation mode according to the oscillation mode corresponding to the model eigenvalue when the new energy station grid-connected system is unstable.

[0104] Preferably, the calculation formula of the node impedance model of the new energy station grid-connected system includes:

[0105]

[0106] In the above formula, s is the pull-type operator, s′ is the coupling frequency pull-down operator, is the n+1-dimensional positive sequence small signal current component, is the n+1-dimensional negative sequence small signal current component, is the positive sequence node admittance matrix of the network element, is the negative-sequence node admittance matrix of the network elements, is the positive sequence admittance diagonal matrix of the converter, is a diagonal matrix composed of the coupled admittances calculated from the negative sequence current disturbance component and the positive sequence voltage disturbance component at each node in the new energy station. is the diagonal matrix composed of the converter coupling admittance calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at each node in the new energy station. is the negative sequence admittance diagonal matrix of the converter, is the n+1-dimensional positive sequence small signal voltage component, It is the n+1-dimensional negative-sequence small signal voltage component.

[0107] Preferably, the calculation formula of the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system includes:

[0108]

[0109] The calculation formula of the characteristic equation of the node impedance model of the new energy station grid-connected system includes:

[0110]

[0111] In the above formula, s is the pull operator, det(・) is the determinant to be solved, Y net (s) is the 2(n+1)-dimensional admittance matrix of the network element, Y reg (s) is the 2(n+1)-dimensional admittance matrix of the converter.

[0112] Preferably, the calculation formula for solving the determinant of the n+1-dimensional ordered impedance matrix includes:

[0113]

[0114] The calculation formula of the model characteristic value includes:

[0115]

[0116] In the above formula, s is the pull operator, det(・) is the determinant to be solved, For Solve the determinant, is the corrected equivalent positive sequence admittance of the new energy station grid-connected system, L for The left eigenvector matrix of is the eigenvalue diagonal matrix, diag{·} is the diagonal matrix, λ n is the nth eigenvalue, λ n+1is the n+1th eigenvalue, n+1 is the order of the matrix, T for The right eigenvector matrix of .

[0117] Preferably, the calculation formula for the participation factor of the converter access node in the new energy station grid-connected system includes:

[0118] p i =L ik •T ik

[0119] In the above formula, i is the converter access node in the new energy station grid-connected system, p i Connecting nodes to converters in new energy station grid-connected systems i The participation factor, T ik To reflect the converter access nodes in the new energy station grid-connected system i The injection current k The characteristic trajectory effect, L ik for T ik The corresponding weight of the new energy station grid-connected system mode.

[0120] Preferably, the optimization configuration unit includes:

[0121] The selection module is used to select the grid-following converter connected to the node with the largest participation factor from the participation factors of the converter access nodes in the new energy station grid-connected system, and replace it with a grid-forming converter of the same capacity.

[0122] According to a third aspect of an embodiment of the present application, there is provided a computer device, comprising: one or more processors;

[0123] The processor is configured to store one or more programs;

[0124] When the one or more programs are executed by the one or more processors, the new energy station networking unit optimization configuration method is implemented.

[0125] According to a fourth aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed, the method for optimizing the configuration of the grid-type units of the new energy station is implemented.

[0126] The technical solution provided by the present invention has the following beneficial effects:

[0127] The present invention provides a method and device for optimizing the configuration of grid-connected units of a new energy station. The method collects relevant parameters of a grid-connected system of a new energy station and uses the relevant parameters of the grid-connected system of the new energy station to calculate a wide-band oscillation stability margin index of the grid-connected system of the new energy station. Based on the wide-band oscillation stability margin index of the grid-connected system of the new energy station, it is determined whether the grid-connected system of the new energy station needs to be optimized. When the grid-connected system of the new energy station needs to be optimized, the node impedance model of the grid-connected system of the new energy station is used to calculate the participation factor of each converter access node in the grid-connected system of the new energy station. Based on the participation factor of each converter access node in the grid-connected system of the new energy station, the grid-connected units of the grid-connected system of the new energy station are optimized, and the wide-band oscillation stability margin index of the grid-connected system of the new energy station is recalculated until the grid-connected system of the new energy station reaches the optimal configuration. This method can ensure the wide-band oscillation stability margin of the grid-connected system while reasonably configuring the capacity and position of the grid-connected units. BRIEF DESCRIPTION OF THE DRAWINGS

[0128] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0129] Figure 1 Schematic diagram of a typical renewable energy power generation grid-connected converter structure and grid-following and grid-forming control structures provided by an embodiment of the present invention;

[0130] Figure 2 This is a control block diagram of a grid-following type and a grid-forming type converter provided by an embodiment of the present invention;

[0131] Figure 3 Schematic diagram of a small signal impedance circuit model of a new energy station grid-connected system provided by an embodiment of the present invention;

[0132] Figure 4 This is a network topology diagram of a typical new energy station grid-connected system provided by an embodiment of the present invention;

[0133] Figure 5 Schematic diagram of a small-signal circuit model of sequence impedance of a new energy station grid-connected system provided by an embodiment of the present invention;

[0134] Figure 6 This is a flow chart of a method for optimizing configuration of grid-type units of a new energy station provided by an embodiment of the present invention;

[0135] Figure 7Schematic diagram of the transmission relationship between the positive and negative sequence voltage and current small signal components of the nodes of the new energy station grid-connected system provided by an embodiment of the present invention;

[0136] Figure 8 Schematic diagram of the transmission feedback relationship of the node impedance model of the new energy station grid-connected system provided by an embodiment of the present invention;

[0137] Figure 9 This is a flow chart of a method for optimizing configuration of grid-type units of a new energy station provided by an embodiment of the present invention;

[0138] Figure 10 This is a network topology diagram of a new energy station provided by an embodiment of the present invention;

[0139] Figure 11 This is a heat map of the participation factors of new energy station nodes provided by an embodiment of the present invention;

[0140] Figure 12 This is a Nyquist diagram of a new energy station grid-connected system provided by an embodiment of the present invention;

[0141] Figure 13 This is a Bode diagram of a new energy station grid-connected system provided by an embodiment of the present invention;

[0142] Figure 14 This is a schematic diagram of the change trend of the participation factors of some nodes in the new energy station provided by an embodiment of the present invention;

[0143] Figure 15 is a schematic diagram of a current waveform at a system grid connection point before configuration provided by an embodiment of the present invention;

[0144] Figure 16 is a schematic diagram of the current waveform of the grid-connected point of the system after configuration provided by an embodiment of the present invention;

[0145] Figure 17 This is a structural block diagram of a new energy station network unit optimization configuration device provided by an embodiment of the present invention;

[0146] Figure 18 This is a structural block diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0147] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the following embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0148] Example 1

[0149] Typical renewable energy power generation grid-connected converter structure and grid-following and grid-forming control structures are as follows: Figure 1 As shown in the figure, i Labc is the abc three-phase filter inductor current, v abc is the three-phase voltage of abc, i abc is the three-phase current abc, v dc is the DC side voltage of the converter, θ is the phase-locking angle, dq represents the synchronous rotating coordinate system, abc Represents a three-phase stationary coordinate system. Grid-following control includes a phase-locked loop (PLL), a voltage loop, and a current loop. The PLL tracks the grid phase by inputting the collected grid connection point voltage. The voltage loop controls the DC bus capacitor to maintain a constant DC voltage and provides a reference current for the inner current loop. The current loop outputs a PWM modulation reference signal to maintain a constant converter output current waveform.

[0150] The grid-forming control includes an active power loop, a reactive power loop, and a cascaded voltage and current inner loop. A virtual impedance link is added before the cascade inner loop to improve the converter's dynamic characteristics and stability. The power control link adopts a virtual synchronous control strategy, which synchronizes with the grid by mimicking the motion equations of traditional synchronous generators. Detailed control block diagrams of typical grid-following and grid-forming converters are shown in Figure 2 , in the figure, P is the active power, Q is the reactive power, P ref is the active power reference value, Q ref is the reactive power reference value, J is the virtual moment of inertia, D p is the damping coefficient, D q is the voltage droop coefficient, K is the reactive power control integral coefficient, |V ref | is the absolute value of the reference voltage, |V| is the absolute value of the collected voltage, ψ is the virtual back EMF, H v (s) is the voltage loop transfer function, H i (s) is the current loop transfer function, L v is the virtual inductor, i d is the d-axis current, i qis the q-axis current, V d is the d-axis voltage, V q is the q-axis voltage, C f is the filter capacitor, i Ld is the d-axis inductor current, i Lq is the q-axis inductor current, L f is the filter inductor, E d is the d-axis modulation reference voltage, E q is the q-axis modulation reference voltage, ω 0 is the rated angular frequency.

[0151] The frequency domain small signal impedance method has been proposed in recent years and applied to the modeling and stability analysis of renewable energy station grid-connected systems. The impedance model of a renewable energy power generation unit is generally described as a 2×2 transfer function matrix in the form of admittance, as follows:

[0152] (1)

[0153] Where s is the Laplace operator (i.e., Laplace operator), s′ is the Laplace operator at the coupling frequency, s′=s-j2ω1, j is the imaginary number sign, ω1 is the rated angular frequency, Y p (s) and Y n (s′) represents the disturbance response characteristics of the new energy power generation unit when the voltage and current are at the same frequency, Y c (s) and Y r (s′) represents the coupling characteristics of the new energy power generation unit between voltage and current at different frequencies. is the positive sequence small signal voltage component, is the negative sequence small signal voltage component, is the positive sequence small signal current component, It is the negative sequence small signal current component.

[0154] Based on this, the small signal model of the new energy station grid-connected system can be described as a small signal impedance circuit model at two coupling frequencies, such as Figure 3 shown. Figure 3 middle, is the small signal component of the positive sequence grid voltage, is the small signal component of the positive sequence grid current, The negative sequence current is a small signal component of the grid current. The negative sequence current response generated by the renewable energy generation unit at the coupling frequency is controlled by the controlled current source. This means that the current passing through the grid and the inverter impedance will generate a negative sequence voltage at the inverter port. , which in turn will generate a positive sequence current response at the original disturbance frequency , and The expression is as follows:

[0155] (2)

[0156] (3)

[0157] In the above formula, is a controlled current source, is the positive sequence current response, is the positive sequence small signal voltage component, It is the negative sequence small signal voltage component.

[0158] Based on the above impedance model, the stability analysis of the new energy station grid-connected system adopts the generalized Nyquist criterion. The system stability is determined by solving and analyzing the loci of the two characteristic roots of formula (4) around the point (-1, j0), where j is the imaginary number symbol. The characteristic root loci of formula 4 are on the complex plane, and generally the horizontal axis is the real axis and the vertical axis is the imaginary axis.

[0159] (4)

[0160] In the above formula, L ′ is the return ratio matrix of the new energy station grid-connected system, Y g (s) and Y g (s′) is the admittance of the grid impedance at two frequencies.

[0161] It should be noted that formula (4) is a second-order matrix. Solving formula (4) will obtain two characteristic roots. Changing s will result in a series of two different characteristic roots.

[0162] Taking wind farms as an example, the network topology of a typical new energy station grid-connected system is as follows: Figure 4 As shown in Figure 1, multiple renewable energy generation units are connected in parallel to medium-voltage feeders via converters and box-type step-up transformers. These feeders are then connected to the station's busbar and finally to the grid via the main transformer. Modeling must consider the station's internal network topology and the frequency coupling characteristics of the generation units.

[0163] Based on the small signal impedance circuit model of the new energy power generation unit grid-connected system mentioned above, a small signal impedance network model of the new energy station grid-connected system is established as follows: Figure 5 As shown in the figure, is the positive sequence grid admittance, is the negative sequence grid admittance, is the positive sequence line admittance between node 0 and node 1, is the negative sequence line admittance between node 0 and node 1, is the positive sequence small signal voltage component of node n, is the negative sequence small signal voltage component of node n, is the positive sequence converter admittance at node n, Negative sequence converter admittance at node n, is the positive sequence small signal current coupling component of node n, is the negative sequence small signal current coupling component of node n. There are n+1 nodes in the grid-connected system of renewable energy power generation units, including n renewable energy station nodes and grid connection points (i.e., node #0, where #0 is the node number of the grid connection point). s is a pull operator, s′=s-j2ω1, and ω1 is the rated angular frequency. Since the sequence impedance small signal circuit model is symmetrical, taking the positive sequence circuit model as an example, is the grid positive sequence impedance, is the voltage small disturbance component of node i in the new energy station, is the positive sequence admittance of the line between node j and node k in the grid-connected system. The converter considering the frequency coupling effect can be expressed as the converter positive sequence admittance Y pp (s) Connect a controlled current source in parallel .

[0164] This paper mainly aims at the broadband oscillation problem of renewable energy grid connection, and proposes a method for optimizing the configuration of renewable energy station grid-connected units. Figure 6 As shown, the following steps are included:

[0165] Step 101: Collect relevant parameters of the new energy station grid-connected system;

[0166] Step 102: Calculate the broadband oscillation stability margin index of the new energy station grid connection using relevant parameters of the new energy station grid connection system;

[0167] Step 103: Determine whether the grid-connected system of the new energy station needs to be optimized based on the broadband oscillation stability margin index of the new energy station grid-connected system;

[0168] Step 104: When the new energy station grid-connected system needs to be optimized, the node impedance model of the new energy station grid-connected system is used to calculate the participation factor of each converter access node in the new energy station grid-connected system;

[0169] Step 105: Based on the participation factors of the converter access nodes in the new energy station grid-connected system, the grid-connected unit of the new energy station grid-connected system is optimized, and the wide-band oscillation stability margin index of the new energy station grid-connected system is recalculated until the new energy station grid-connected system reaches the optimal configuration.

[0170] Furthermore, the relevant parameters of the new energy station grid connection system include:

[0171] The operating point parameters of the new energy station grid-connected system, the network topology parameters of the new energy station grid-connected system, and the control parameters of the new energy power generation unit;

[0172] The operating point parameters of the new energy station grid-connected system include: voltage signals and current signals of each node in the new energy station grid-connected system;

[0173] The network topology parameters of the new energy station grid-connected system include: the node admittance matrix of the new energy station grid-connected system;

[0174] The control parameters of the new energy power generation unit include: main circuit parameters and control parameters of the new energy power generation unit;

[0175] The main circuit parameters include: rated capacity, rated voltage, filter inductance and filter capacitance of the converter main circuit;

[0176] The control parameters include control parameters of a power link, a voltage link, a current link and a virtual impedance used in the converter controller.

[0177] Furthermore, step 102 includes:

[0178] Step 1021: Based on the relevant parameters of the new energy station grid-connected system, the impedance ratio of the new energy station grid-connected system is calculated using a pre-built new energy side aggregate impedance model;

[0179] Specifically, the calculation formula of the new energy side aggregation impedance model includes:

[0180]

[0181] The calculation formula for the grid-connected system impedance ratio of new energy stations includes:

[0182]

[0183] In the above formula, is the aggregate admittance of the new energy station, is the aggregate impedance of the new energy station, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the grid connection point of the new energy station. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the grid connection point of the new energy station. is the negative sequence admittance on the grid side, is the negative sequence admittance of the new energy station, s is the pull operator, s′ is the coupling frequency pull-down operator, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, Z g (s) is the positive sequence impedance on the grid side;

[0184] Step 1022: Calculate the stability margin function of the new energy station grid-connected system using the impedance ratio of the new energy station grid-connected system;

[0185] Specifically, the calculation formula for the stability margin function of the new energy station grid-connected system includes:

[0186] G(s)=1+Z ratio (s)

[0187] In the above formula, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, G(s) is the stability margin function of the grid-connected system of new energy stations, and s is the pull operator;

[0188] Step 1023: Calculate the wide-band oscillation stability margin index of the new energy station grid connection using the new energy station grid connection system stability margin function;

[0189] Specifically, the calculation formula for the broadband oscillation stability margin index of the new energy station grid connection includes:

[0190]

[0191] In the above formula, γ It is the broadband oscillation stability margin index for new energy stations connected to the grid. s = jω , G(jω) is the stability margin function of the grid-connected system of new energy stations, j is the imaginary number symbol, ω is the angular frequency.

[0192] Furthermore, step 103 includes:

[0193] Determine whether the broadband oscillation stability margin index of the new energy station grid is greater than or equal to the margin threshold. If the broadband oscillation stability margin index of the new energy station grid is greater than or equal to the margin threshold, the new energy station grid-connected system is stable, the new energy station grid-connected system does not need to be optimized, and the current configuration of the new energy station grid-connected system is the optimal configuration; if the broadband oscillation stability margin index of the new energy station grid-connected system is less than the margin threshold, the new energy station grid-connected system is unstable, and the new energy station grid-connected system needs to be optimized.

[0194] Furthermore, step 104 includes:

[0195] Step 1041: Obtain a characteristic equation of the node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system;

[0196] Step 1042: Using the characteristic equation of the node impedance model of the new energy station grid-connected system, obtain the participation factor of each converter access node in the new energy station grid-connected system.

[0197] Furthermore, step 1041 includes:

[0198] Step 1041a: Determine the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system;

[0199] Step 1041b: Set the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system to zero, and simplify to obtain the characteristic equation of the node impedance model of the new energy station grid-connected system.

[0200] Specifically, the calculation formula of the node impedance model of the new energy station grid-connected system includes:

[0201]

[0202] In the above formula, s is the pull-type operator, s′ is the coupling frequency pull-down operator, is the n+1-dimensional positive sequence small signal current component, is the n+1-dimensional negative sequence small signal current component, is the positive sequence node admittance matrix of the network element, is the negative-sequence node admittance matrix of the network elements, is the positive sequence admittance diagonal matrix of the converter, is a diagonal matrix composed of the coupled admittances calculated from the negative sequence current disturbance component and the positive sequence voltage disturbance component at each node in the new energy station. is the diagonal matrix composed of the converter coupling admittance calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at each node in the new energy station. is the negative sequence admittance diagonal matrix of the converter, is the n+1-dimensional positive sequence small signal voltage component, is the n+1-dimensional negative sequence small signal voltage component;

[0203] The calculation formula for the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system includes:

[0204]

[0205] The calculation formula of the characteristic equation of the node impedance model of the new energy station grid-connected system includes:

[0206]

[0207] In the above formula, s is the pull operator, det(・) is the determinant to be solved, Y net (s) is the 2(n+1)-dimensional admittance matrix of the network element, Y reg (s) is the 2(n+1)-dimensional admittance matrix of the converter.

[0208] Furthermore, step 1042 includes:

[0209] Step 1042a: Using Schur complement transformation, transform the characteristic equation of the node impedance model of the new energy station grid-connected system into a solution for the determinant of the n+1-dimensional ordered impedance matrix to obtain the model eigenvalue;

[0210] Step 1042b: Determine the stability information and oscillation property information of the new energy station grid-connected system based on the model eigenvalues;

[0211] Step 1042c: When the new energy station grid-connected system is unstable, the participation factor of each converter access node in the new energy station grid-connected system under the oscillation mode is calculated according to the oscillation mode corresponding to the model eigenvalue.

[0212] Specifically, the calculation formula for solving the determinant of the n+1-dimensional ordered impedance matrix includes:

[0213]

[0214] The calculation formula of the model eigenvalue includes:

[0215]

[0216] In the above formula, s is the pull operator, det(・) is the determinant to be solved, For Solve the determinant, is the corrected equivalent positive sequence admittance of the new energy station grid-connected system, L for The left eigenvector matrix of is the eigenvalue diagonal matrix, diag{·} is the diagonal matrix, λ n is the nth eigenvalue, λ n+1 is the n+1th eigenvalue, n+1 is the order of the matrix, T for The right eigenvector matrix of ;

[0217] The calculation formula for the participation factor of the converter access node in the new energy station grid-connected system includes:

[0218] p i =L ik •T ik

[0219] In the above formula, i is the converter access node in the new energy station grid-connected system, p i Connecting nodes to converters in new energy station grid-connected systems i The participation factor, T ik To reflect the converter access nodes in the new energy station grid-connected system i The injection current k The characteristic trajectory effect, L ik for T ik The corresponding weight of the new energy station grid-connected system mode.

[0220] Furthermore, in step 105, the grid-connected unit of the new energy station grid-connected system is optimized according to the participation factor of each converter access node in the new energy station grid-connected system, including:

[0221] From the participation factors of each converter access node in the new energy station grid-connected system, the grid-following converter connected to the node with the largest participation factor is selected and replaced with a grid-forming converter of the same capacity.

[0222] To further illustrate the above-mentioned method for optimizing the configuration of grid-type units of new energy stations, the present invention provides an example, comprising the following steps:

[0223] (1) Establish the capacity and layout configuration problem of the grid-connected units of the new energy station. The goal is to minimize the total capacity of the grid-connected units in the grid-connected system of the new energy station. Set the stability margin index γ of the grid-connected system of the new energy station to evaluate the stable operation capability of the grid-connected system of the new energy station. The stability margin γ of the grid-connected system of the new energy station after the optimized configuration needs to meet the minimum stability margin under the rated stable operation condition of the grid-connected system of the new energy station.

[0224] (2) Wideband oscillation stability margin

[0225] The stability margin function of the new energy station grid-connected system is used to measure the stability of the new energy station grid-connected system, which can be specifically expressed as:

[0226] G(s)=1+Zratio (s) (5)

[0227] In the above formula, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, G(s) It is a deformation and extension of the Nyquist curve of the new energy station grid-connected system, so it contains the complete broadband oscillation risk constraints of the new energy station grid-connected system. The broadband oscillation stability margin index γ of the new energy station grid-connected system is calculated based on G(s), which can be specifically expressed as

[0228]

[0229] In the above formula, γ It is the broadband oscillation stability margin index for new energy stations connected to the grid. s = jω , G(jω) is the stability margin function of the grid-connected system of new energy stations, j is the imaginary number symbol, ω is the angular frequency;

[0230] according to Figure 5 , the relationship between the voltage and current small signal sequence components of the new energy station at the grid connection point is:

[0231] (7)

[0232] In the above formula, s is the Laplace operator, s′ is the Laplace operator at the coupling frequency, and are the positive and negative sequence components of the small signal current at the grid connection point, and are the positive and negative sequence components of the small signal voltage at the grid connection point, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the station grid connection point. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the station grid connection point. is the negative sequence admittance of the new energy station, Y stn It is the equivalent sequence impedance model of the new energy station.

[0233] From formula (7), we can see that Y stn It is a two-dimensional impedance model that aggregates the internal nodes of the station at the grid connection point. It includes the unified influence of the network topology of the new energy station and the frequency coupling effect of the internal converter on the small signal voltage and current components of the system grid connection point. It is essentially a full-order aggregated node frequency domain model.

[0234] When analyzing the stability of the grid-connected system of new energy stations, the system stability can be determined by solving the two sets of eigenvalues ​​of equation (8) and using the generalized Nyquist criterion.

[0235] (8)

[0236] In the above formula, H is the ratio matrix of the transfer function relationship between the voltage and current disturbance components at the grid connection point in the new energy station grid connection system, is the positive sequence admittance on the grid side, is the negative sequence admittance on the grid side, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the station grid connection point. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the station grid connection point. is the negative sequence admittance of the new energy station;

[0237] right H Perform Schur complement transformation to convert it into the new energy side aggregation impedance model, which can be specifically expressed as:

[0238] (9)

[0239] In the above formula, is the aggregate admittance of the new energy station, is the aggregate impedance of the new energy station, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the station grid connection point. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the station grid connection point. is the negative sequence admittance on the grid side, is the negative sequence admittance of the new energy station;

[0240] By solving the ratio of the corrected sequence impedance of the new energy station to the grid impedance The Nyquist curve of the grid can be used to determine the stability of the grid-connected system of the new energy station. Substituting into equation (5) we can solve the system stability margin function G(s) and the broadband oscillation stability margin γ.

[0241] (3) Active power output boundary under stability constraints

[0242] Gradually increase the active power output of the grid-connected system of the new energy station. When the system is in a critical stable state, the active power output of the grid-connected system of the new energy station is recorded as the maximum active power output point P at which the system can operate stably. cr .

[0243] The maximum active power output point is an operating indicator of a new energy station. By comparing the changes in the maximum active power output point of the grid-connected system of the new energy station before and after the optimized configuration, we can highlight the conclusion that the optimized configuration method can improve the effectiveness of the stable output of the grid-connected system of the new energy station under this operating condition.

[0244] (4) Participation factor of node oscillation mode within the station

[0245] according to Figure 5 The KCL equations (current node method equations based on Kirchhoff's Current Law) for each node of the renewable energy station grid-connected system are obtained as follows:

[0246] (10)

[0247] In the above formula, and are n+1-dimensional positive and negative sequence small signal current components, and They are n+1-dimensional positive and negative sequence small signal voltage components respectively. and are the positive and negative sequence admittance matrices of the impedance network, which include the positive and negative sequence admittances of the network elements and the positive and negative sequence admittances of the converter. They can be expressed as follows:

[0248] (11)

[0249] In the above formula, and are the positive and negative sequence node admittance matrices of network elements, and is the positive and negative sequence admittance diagonal matrix of the converter.

[0250] and They are n+1-dimensional controlled current source components, which can be expressed as:

[0251] (12)

[0252] In the above formula, and is the diagonal matrix of the converter coupling admittance. Combining the above equations, we can get:

[0253] (13)

[0254] According to formula (13), the transfer relationship between the small signal components of the system node voltage and current can be derived, as follows: Figure 7 shown.

[0255] The positive and negative sequence small signal voltage and current components, the network element node admittance matrix and the converter admittance matrix are recombined according to the node order to obtain the node impedance model that describes the node impedance characteristics of the new energy station grid-connected system. Its transmission feedback relationship is as follows: Figure 8 shown.

[0256] Figure 8 middle, is the inverse of the 2(n+1)-dimensional admittance matrix of the network element, Y reg (s) is the 2(n+1)-dimensional admittance matrix of the converter. and are the small signal voltage and current components of the system node sequence impedance, respectively, which can be expressed as:

[0257] (14)

[0258] (15)

[0259] In the above formula, T is the transpose, m is the total number of nodes in the system, is the positive sequence small signal voltage component of the 0th node, is the negative sequence small signal voltage component at the 0th node, is the positive sequence small signal voltage component of the nth node, is the negative sequence small signal voltage component of the nth node, is the positive sequence small signal current component of the 0th node, is the negative sequence small signal current component at the 0th node, is the positive sequence small signal current component of the nth node, is the negative sequence small signal current component of the nth node.

[0260] Based on the node impedance model of the new energy station grid-connected system, the frequency domain modal participation factor is used to explore the impact of the impedance characteristics of each node in the system on the system stability. Figure 8 It can be seen that the characteristic equation of the model is:

[0261] (16)

[0262] Among them, det(・) represents the determinant solution. The Schur transformation is used to transform Equation (16) into the determinant solution of the n+1-dimensional ordered impedance matrix When the system becomes unstable, the corresponding There is at least one eigenvalue λ=0. Perform eigenvalue decomposition and we can get:

[0263] (17)

[0264] In the above formula, L for The left eigenvector matrix of is the eigenvalue diagonal matrix, T for The right eigenvector matrix of . The participation factor of the converter access node i in the system is defined as:

[0265] p i =L ik •T ik (18)

[0266] In the above formula, p i Connecting nodes to converters in new energy station grid-connected systems i The participation factor, T ik To reflect the node i The injection current k The characteristic trajectory effect, L ik for T ik The weight corresponding to the grid-connected system mode of the new energy station. p i The larger the value, the node i The greater the impact on system instability, the weaker the node is in the system network. Therefore, according to the characteristic equation of the node impedance model of the new energy station grid-connected system, the focus is on calculating the converter access node in the system. p , select the node with the maximum participation factor to replace the grid-connected converter with the same capacity.

[0267] In order to further illustrate the above-mentioned new energy station grid unit optimization configuration method, the present invention also provides an example, such as Figure 9 As shown, the following steps are included:

[0268] Step 1: Input system data. System data mainly includes the operating point parameters of the new energy station grid-connected system, the network topology parameters of the new energy station grid-connected system, and the control parameters of the new energy power generation unit;

[0269] Step 2: Calculate the system broadband oscillation risk constraint. Construct the new energy side aggregation impedance model and calculate Z ratio (s) and judge the system stability, calculate the broadband oscillation stability margin index γ of the new energy station grid connection to evaluate the system's stable operation capability;

[0270] Step 3: Determine whether the broadband oscillation stability margin index γ of the new energy station grid connection meets the broadband oscillation stability margin index threshold γ of the new energy station grid connection min Requirements. If γ satisfies γ min If the requirement is met, the optimization configuration solution is completed and the final optimization configuration result of the system is output; otherwise, the optimization configuration of the system network unit is carried out;

[0271] Step 4: Optimize the configuration of the system grid unit. Construct the node impedance model of the new energy station grid-connected system, calculate the model characteristic equation and the system node participation factor p i , select the node with the largest participation factor as the optimal node to optimize the configuration of the network unit;

[0272] Step 5: Optimization configuration result verification. After the optimization configuration of the new energy station grid-connected system is completed, repeat steps 2 to 4 to iteratively optimize the configuration of the grid unit and verify the configuration results until γ meets γ min Requirement, the optimization configuration solution is completed.

[0273] The present invention proposes a method for optimizing the configuration of grid-forming units at new energy stations, proposes configuration optimization problems, grid-connected stability indicators, output boundary indicators, distribution point participation factors, etc., and proposes an iterative solution method based on the distribution point participation factor, which can achieve the reasonable configuration of the capacity and position of the grid-forming units while ensuring the broadband oscillation stability margin of the grid-connected system.

[0274] In order to further illustrate the above-mentioned new energy station grid unit optimization configuration method, the present invention provides an example in practical application. According to the actual engineering network topology structure, a new energy station grid connection system simulation model is established. The topology diagram is as follows: Figure 10 The station contains three 35kV feeders, each of which is connected to 11 grid-following converters with a rated capacity of 3MW, with a connection spacing of 1km.

[0275] Assume that the station is connected to a weak grid system with SCR=1.8, and gradually increase the system active output. When it decreases to 0, the system has reached the critical stable operation point. The maximum active output of the system under the wide-band oscillation risk constraint is 0.76pu, and optimization configuration is required. The heat map of the participation factor of the new energy station node is as follows: Figure 11 As shown in the figure, the three feeders in the station all follow the rule that the node participation factor is inversely proportional to the distance to the grid connection point, that is, the participation factor of the end node of the feeder is the largest, and the participation factor of the head node of the feeder is the smallest. Figure 11 As can be seen from the figure, due to the inconsistent access spacing of the three feeders at the station, and due to the longer line distances of feeder 1 and feeder 2, their access nodes have a larger participation factor than the access nodes at the same position of feeder 3, and have a greater impact on system stability.

[0276] Based on the participation factor results, the station was configured with grid-connected converters. The iterative process is shown in Table 1. After first deploying 15MW grid-connected converters at the ends of feeders 1 and 2, the system regained stability but still did not meet the stability margin requirements. When eight grid-connected converters were deployed, λ = 0.2409, and the system was able to operate stably under rated conditions. At this point, the configured grid-connected converter capacity accounted for 24.2%.

[0277] Table 1 Iterative solution process for 33*3MW grid-type converter configuration of new energy station

[0278]

[0279] The stability analysis results of the new energy station grid-connected system are as follows: Figure 12 and Figure 13 Before configuration, the system is in a critical instability state. Figure 12 The Nyquist curve of the system impedance ratio just surrounds the point (-1, j0), Figure 13 The impedance curve of the grid-connected substation system intersects the grid impedance at 33Hz and 67Hz. The system phase margin is insufficient at these intersection frequencies, leading to subsynchronous and supersynchronous small-signal instability. After this configuration, the system impedance ratio Nyquist curve no longer surrounds the (-1, j0) point, and the phase margin at the intersection frequency between the system aggregate impedance curve and the grid impedance is increased to 16.2°, meeting the requirements for stable system operation.

[0280] The change trend of the participation factor of the converter access node in the new energy station is as follows: Figure 14 As shown. It can be found from the figure that the participation factors of the configured nodes in the station show an overall downward trend, indicating that after configuration, the influence of the converter nodes that originally had a greater impact on the small signal instability of the system gradually decreases. In addition, before the configuration begins, the participation factors of the #1, #3, #5, #7 and #9 nodes in feeder 1 are higher than those of the #23, #25 and #27 nodes in feeder 2. This is because the node access spacing of feeder 1 is larger than that of feeder 2, which has a greater impact on the broadband oscillation stability of the system. In the first two iterative optimizations, the main focus is on the end nodes on feeder 1. Afterwards, as the participation factors of the converter nodes on feeder 1 decrease after configuration, the participation factors of the end nodes on feeder 2 increase relatively, approaching the participation factors of some nodes in feeder 1. Therefore, in the middle and late stages of optimization, the nodes of feeder 1 and feeder 2 are alternately configured, and the participation factors of the two feeder nodes show an alternating downward trend until the system meets γ min The minimum active power output point P for the system to operate stably crmin Require.

[0281] The above working conditions are verified in time domain simulation. The simulation waveform of the current at the grid connection point of the new energy station grid connection system is as follows: Figure 15and Figure 16 Before the optimization configuration, the maximum active power output of the system under the broadband oscillation risk constraint is 0.76pu. At this time, the system is in a critical stable state, and the grid-connected current waveform oscillates, as shown in Figure 2. Figure 15 The grid-connected point current waveform was extracted and FFT analysis was performed. The results showed that there were 33Hz and 67Hz oscillation components in the current, and the system was at risk of sub- / super-synchronous oscillation. After the optimized configuration, the system resumed rated output operation. At this time, the grid-connected point current waveform was as follows: Figure 16 As shown in the figure, the current waveform at the grid connection point is smooth and has no obvious oscillation component, which is consistent with the theoretical analysis results, verifying the effectiveness of the grid-connected unit optimization configuration method for the new energy station grid-connected system.

[0282] Example 2

[0283] The present invention also provides a new energy station network unit optimization configuration device, such as Figure 17 Shown, including:

[0284] The acquisition unit is used to collect relevant parameters of the grid-connected system of the new energy station;

[0285] The first calculation unit is used to calculate the broadband oscillation stability margin index of the new energy station grid connection using relevant parameters of the new energy station grid connection system;

[0286] A judgment unit, used to judge whether the grid-connected system of the new energy station needs to be optimized according to the broadband oscillation stability margin index of the grid-connected new energy station;

[0287] The second calculation unit is used to calculate the participation factor of each converter access node in the new energy station grid-connected system by using the node impedance model of the new energy station grid-connected system when the new energy station grid-connected system needs to be optimized;

[0288] The optimization configuration unit is used to optimize the configuration of the grid-connected units of the new energy station grid-connected system according to the participation factors of each converter access node in the new energy station grid-connected system, and recalculate the wide-band oscillation stability margin index of the new energy station grid-connected system until the new energy station grid-connected system reaches the optimal configuration.

[0289] Furthermore, the relevant parameters of the new energy station grid connection system include: operating point parameters of the new energy station grid connection system, network topology parameters of the new energy station grid connection system and control parameters of the new energy power generation unit;

[0290] The operating point parameters of the new energy station grid-connected system include: voltage signals and current signals of each node in the new energy station grid-connected system;

[0291] The network topology parameters of the new energy station grid-connected system include: the node admittance matrix of the new energy station grid-connected system;

[0292] The control parameters of the new energy power generation unit include: main circuit parameters and control parameters of the new energy power generation unit;

[0293] The main circuit parameters include: rated capacity, rated voltage, filter inductance and filter capacitance of the converter main circuit;

[0294] The control parameters include control parameters of a power link, a voltage link, a current link and a virtual impedance used in the converter controller.

[0295] Furthermore, the first computing unit includes:

[0296] The first calculation module is used to calculate the impedance ratio of the new energy station grid-connected system based on relevant parameters of the new energy station grid-connected system and using a pre-built new energy side aggregation impedance model;

[0297] The second calculation module is used to calculate the stability margin function of the new energy station grid-connected system using the impedance ratio of the new energy station grid-connected system;

[0298] The third calculation module is used to calculate the wide-band oscillation stability margin index of the new energy station grid connection by using the new energy station grid connection system stability margin function.

[0299] Furthermore, the calculation formula of the new energy side aggregation impedance model includes:

[0300]

[0301] The calculation formula for the grid-connected system impedance ratio of new energy stations includes:

[0302]

[0303] In the above formula, is the aggregate admittance of the new energy station, is the aggregate impedance of the new energy station, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the grid connection point of the new energy station. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the grid connection point of the new energy station. is the negative sequence admittance on the grid side, is the negative sequence admittance of the new energy station, s is the pull operator, s′ is the coupling frequency pull-down operator, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, Zg (s) is the positive sequence impedance on the grid side.

[0304] Furthermore, the calculation formula for the stability margin function of the new energy station grid-connected system includes:

[0305] G(s)=1+Z ratio (s)

[0306] In the above formula, Z ratio (s) is the impedance ratio of the grid-connected system of the new energy station, G(s) is the stability margin function of the grid-connected system of new energy stations, and s is a pull operator.

[0307] Furthermore, the calculation formula for the broadband oscillation stability margin index of the new energy station grid connection includes:

[0308]

[0309] In the above formula, γ It is the broadband oscillation stability margin index for new energy stations connected to the grid. s = jω , G(jω) is the stability margin function of the grid-connected system of new energy stations, j is the imaginary number symbol, ω is the angular frequency.

[0310] Furthermore, the judging unit is specifically configured to:

[0311] Determine whether the broadband oscillation stability margin index of the new energy station grid is greater than or equal to the margin threshold. If the broadband oscillation stability margin index of the new energy station grid is greater than or equal to the margin threshold, the new energy station grid-connected system does not need to be optimized, and the current configuration of the new energy station grid-connected system is the optimal configuration; if the broadband oscillation stability margin index of the new energy station grid-connected system is less than the margin threshold, the new energy station grid-connected system needs to be optimized.

[0312] Furthermore, the second computing unit includes:

[0313] A first acquisition module is used to obtain a characteristic equation of the node impedance model of the new energy station grid-connected system based on the node impedance model of the new energy station grid-connected system;

[0314] The second acquisition module is used to obtain the participation factor of each converter access node in the new energy station grid-connected system by using the characteristic equation of the node impedance model of the new energy station grid-connected system.

[0315] Furthermore, the first acquisition module includes:

[0316] A first determination submodule is configured to determine a denominator of a closed-loop transfer function of a node impedance model of a new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system;

[0317] The first acquisition submodule is used to make the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system equal to zero, and simplify to obtain the characteristic equation of the node impedance model of the new energy station grid-connected system.

[0318] Furthermore, the second acquisition module includes:

[0319] The second acquisition submodule is used to convert the characteristic equation of the node impedance model of the new energy station grid-connected system into a solution for solving the determinant of the n+1 dimensional ordered impedance matrix using Schur complement transformation to obtain the model eigenvalue;

[0320] The second determination submodule is used to determine the stability information and oscillation property information of the new energy station grid-connected system according to the model characteristic value;

[0321] The calculation submodule is used to calculate the participation factor of each converter access node in the new energy station grid-connected system under the oscillation mode according to the oscillation mode corresponding to the model eigenvalue when the new energy station grid-connected system is unstable.

[0322] Furthermore, the calculation formula of the node impedance model of the new energy station grid-connected system includes:

[0323]

[0324] In the above formula, s is the pull-type operator, s′ is the coupling frequency pull-down operator, is the n+1-dimensional positive sequence small signal current component, is the n+1-dimensional negative sequence small signal current component, is the positive sequence node admittance matrix of the network element, is the negative-sequence node admittance matrix of the network elements, is the positive sequence admittance diagonal matrix of the converter, is a diagonal matrix composed of the coupled admittances calculated from the negative sequence current disturbance component and the positive sequence voltage disturbance component at each node in the new energy station. is the diagonal matrix composed of the converter coupling admittance calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at each node in the new energy station. is the negative sequence admittance diagonal matrix of the converter, is the n+1-dimensional positive sequence small signal voltage component, It is the n+1-dimensional negative-sequence small signal voltage component.

[0325] Furthermore, the calculation formula of the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system includes:

[0326]

[0327] The calculation formula of the characteristic equation of the node impedance model of the new energy station grid-connected system includes:

[0328]

[0329] In the above formula, s is the pull operator, det(・) is the determinant to be solved, Y net (s) is the 2(n+1)-dimensional admittance matrix of the network element, Y reg (s) is the 2(n+1)-dimensional admittance matrix of the converter.

[0330] Furthermore, the calculation formula for solving the determinant of the n+1-dimensional order impedance matrix includes:

[0331]

[0332] The calculation formula of the model eigenvalue includes:

[0333]

[0334] In the above formula, s is the pull operator, det(・) is the determinant to be solved, For Solve the determinant, is the corrected equivalent positive sequence admittance of the new energy station grid-connected system, L for The left eigenvector matrix of is the eigenvalue diagonal matrix, diag{·} is the diagonal matrix, λ n is the nth eigenvalue, λ n+1 is the n+1th eigenvalue, n+1 is the order of the matrix, T for The right eigenvector matrix of .

[0335] Furthermore, the calculation formula for the participation factor of the converter access node in the new energy station grid-connected system includes:

[0336] p i =L ik •T ik

[0337] In the above formula, i is the converter access node in the new energy station grid-connected system, p i Connecting nodes to converters in new energy station grid-connected systems i The participation factor, T ik To reflect the converter access nodes in the new energy station grid-connected system i The injection current k The characteristic trajectory effect, L ik for T ik The corresponding weight of the new energy station grid-connected system mode.

[0338] Furthermore, the configuration unit is optimized, including:

[0339] The selection module is used to select the grid-following converter connected to the node with the largest participation factor from the participation factors of the converter access nodes in the new energy station grid-connected system, and replace it with a grid-forming converter with the same capacity.

[0340] It can be understood that the device embodiment provided above corresponds to the method embodiment above, and the corresponding specific contents can be referenced to each other and will not be repeated here.

[0341] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0342] Example 3

[0343] like Figure 18 As shown, the present invention also provides an electronic device, which may be a computer, a single-chip microcomputer, a smart mobile device, or the like. The electronic device in this embodiment may include a processor, a memory, a transceiver component, and the like. The memory, processor, and transceiver component are connected via a bus; the memory may be used to store an execution program, which may include instructions; and the processor may be used to execute the instructions stored in the memory. The memory may also be used to store data, which may be accessed and / or modified during the execution of the instructions.

[0344] The processor may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the storage medium to implement the corresponding method flow or corresponding function, so as to realize the steps of a new energy site networking unit optimization configuration method in the above embodiment.

[0345] Example 4

[0346] Based on the same inventive concept, the present invention also provides a readable storage medium, specifically an electronic device-readable storage medium (Memory). The electronic device-readable storage medium is a memory device in the electronic device for storing programs and data. It is understood that the storage medium herein may include both built-in storage media in the electronic device and, of course, extended storage media supported by the electronic device. The storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for being loaded and executed by a processor. These instructions may be one or more executable programs (including program code). It should be noted that the storage medium herein may be high-speed RAM memory or non-volatile memory, such as at least one disk storage device. The processor loads and executes the one or more instructions stored in the storage medium to implement the steps of the method for optimizing the configuration of a new energy station network unit in the above-mentioned embodiment.

[0347] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0348] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0349] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0350] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0351] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing the configuration of grid-type units of new energy stations, characterized in that: include: Collect relevant parameters of the new energy station grid connection system; Utilizing the relevant parameters of the new energy station grid-connected system, a wide-band oscillation stability margin index of the new energy station grid-connected system is calculated; According to the broadband oscillation stability margin index of the new energy station grid connection, determine whether the new energy station grid connection system needs to be optimized; When the grid-connected system of a new energy station needs to be optimized, the node impedance model of the grid-connected system of the new energy station is used to calculate the participation factor of each converter access node in the grid-connected system of the new energy station; Optimizing the grid-connected unit configuration of the new energy station grid-connected system based on the participation factor of each converter access node in the new energy station grid-connected system, and recalculating the wide-band oscillation stability margin index of the new energy station grid-connected system until the new energy station grid-connected system reaches an optimal configuration; When the new energy station grid-connected system needs to be optimized, the node impedance model of the new energy station grid-connected system is used to calculate the participation factor of each converter access node in the new energy station grid-connected system, including: According to the node impedance model of the new energy station grid-connected system, a characteristic equation of the node impedance model of the new energy station grid-connected system is obtained; Using the characteristic equation of the node impedance model of the new energy station grid-connected system, the participation factor of each converter access node in the new energy station grid-connected system is obtained; The step of obtaining the characteristic equation of the node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system comprises: Determining a denominator of a closed-loop transfer function of the node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system; Setting the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system to zero, and simplifying to obtain the characteristic equation of the node impedance model of the new energy station grid-connected system; The method of using the characteristic equation of the node impedance model of the new energy station grid-connected system to obtain the participation factor of each converter access node in the new energy station grid-connected system includes: Using Schur complement transformation, the characteristic equation of the node impedance model of the new energy station grid-connected system is transformed into the solution of the determinant of the n+1 dimensional ordered impedance matrix to obtain the model eigenvalue; Determining stability information and oscillation property information of the new energy station grid-connected system according to the model characteristic value; When the new energy station grid-connected system is unstable, calculating, according to the oscillation mode corresponding to the model eigenvalue, the participation factor of each converter access node in the new energy station grid-connected system under the oscillation mode; The step of optimizing the grid-connected unit configuration of the new energy station grid-connected system according to the participation factor of each converter access node in the new energy station grid-connected system includes: From the participation factors of the converter access nodes in the new energy station grid-connected system, the grid-following converter connected to the node with the largest participation factor is selected and replaced with a grid-forming converter of the same capacity.

2. The method according to claim 1, characterized in that The relevant parameters of the new energy station grid-connected system include: operating point parameters of the new energy station grid-connected system, network topology parameters of the new energy station grid-connected system and control parameters of the new energy power generation unit; The operating point parameters of the new energy station grid-connected system include: voltage signals and current signals of each node in the new energy station grid-connected system; The network topology parameters of the new energy station grid-connected system include: a node admittance matrix of the new energy station grid-connected system; The control parameters of the new energy power generation unit include: main circuit parameters and control parameters of the new energy power generation unit; The main circuit parameters include: rated capacity and rated voltage of the converter, filter inductance and filter capacitance in the converter main circuit; The control parameters include: control parameters of the power link, voltage link, current link and virtual impedance used in the converter controller.

3. The method according to claim 1, characterized in that The method of calculating the wide-band oscillation stability margin index of the new energy station grid connection system by using the relevant parameters of the new energy station grid connection system includes: Based on the relevant parameters of the new energy station grid-connected system, the impedance ratio of the new energy station grid-connected system is calculated using a pre-built new energy side aggregate impedance model; Calculating a stability margin function of the new energy station grid-connected system using the impedance ratio of the new energy station grid-connected system; The wide-band oscillation stability margin index of the new energy station grid-connected system is calculated using the new energy station grid-connected system stability margin function.

4. The method according to claim 3, characterized in that The calculation formula of the new energy side aggregation impedance model includes: The calculation formula for the grid-connected system impedance ratio of the new energy station includes: In the above formula, is the aggregate admittance of the new energy station, is the aggregate impedance of the new energy station, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the grid connection point of the new energy station. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the grid connection point of the new energy station. is the negative sequence admittance on the grid side, is the negative sequence admittance of the new energy station, s is the pull operator, s′ is the coupling frequency pull-down operator, is the impedance ratio of the grid-connected system of the new energy station, is the positive sequence impedance on the grid side.

5. The method according to claim 3, characterized in that The calculation formula of the new energy station grid-connected system stability margin function includes: In the above formula, is the impedance ratio of the grid-connected system of the new energy station, G(s) is the stability margin function of the grid-connected system of the new energy station, and s is the pull operator.

6. The method according to claim 3, characterized in that The calculation formula for the broadband oscillation stability margin index of the new energy station grid connection includes: In the above formula, γ is the broadband oscillation stability margin index of the new energy station grid connection, s = jω, G(jω) is the stability margin function of the new energy station grid connection system, j is the imaginary number sign, and ω is the angular frequency.

7. The method according to claim 1, characterized in that The determining whether the grid-connected system of the new energy station needs to be optimized according to the wide-band oscillation stability margin index of the new energy station grid-connected system includes: Determine whether the broadband oscillation stability margin index of the new energy station grid-connected is greater than or equal to the margin threshold. If the broadband oscillation stability margin index of the new energy station grid-connected is greater than or equal to the margin threshold, the new energy station grid-connected system does not need to be optimized, and the current configuration of the new energy station grid-connected system is the optimal configuration; if the broadband oscillation stability margin index of the new energy station grid-connected is less than the margin threshold, the new energy station grid-connected system needs to be optimized.

8. The method according to claim 1, characterized in that The calculation formula of the node impedance model of the new energy station grid-connected system includes: In the above formula, s is the pull-type operator, s′ is the coupling frequency pull-down operator, is the n+1-dimensional positive sequence small signal current component, is the n+1-dimensional negative sequence small signal current component, is the positive sequence node admittance matrix of the network element, is the negative-sequence node admittance matrix of the network elements, is the positive sequence admittance diagonal matrix of the converter, is a diagonal matrix composed of the coupled admittances calculated from the negative sequence current disturbance component and the positive sequence voltage disturbance component at each node in the new energy station. is the diagonal matrix composed of the converter coupling admittance calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at each node in the new energy station. is the negative sequence admittance diagonal matrix of the converter, is the n+1-dimensional positive sequence small signal voltage component, It is the n+1-dimensional negative-sequence small signal voltage component.

9. The method according to claim 1, characterized in that The calculation formula of the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system includes: The calculation formula of the characteristic equation of the node impedance model of the new energy station grid-connected system includes: In the above formula, s is the pull operator, det(•) is the determinant solution, is the 2(n+1)-dimensional admittance matrix of the network element, is the 2(n+1)-dimensional admittance matrix of the converter.

10. The method according to claim 1, characterized in that The calculation formula for solving the determinant of the n+1-dimensional ordered impedance matrix includes: The calculation formula of the model characteristic value includes: In the above formula, s is the pull operator, det(•) is the determinant solution, For Solve the determinant, is the corrected equivalent positive sequence admittance of the new energy station grid-connected system, for The left eigenvector matrix of is the eigenvalue diagonal matrix, diag{·} is the diagonal matrix, λ n is the nth eigenvalue, λ n+1 is the n+1th eigenvalue, n+1 is the order of the matrix, for The right eigenvector matrix of .

11. The method according to claim 1, characterized in that The calculation formula for the participation factor of the converter access node in the new energy station grid-connected system includes: p i =L ik •T ik In the above formula, i is the converter access node in the new energy station grid-connected system, p i is the participation factor of the converter access node i in the new energy station grid-connected system, T ik To reflect the effect of the current injected by the converter access node i on the kth characteristic trajectory in the new energy station grid-connected system, L ik T ik The corresponding weight of the new energy station grid-connected system mode.

12. A new energy station network unit optimization configuration device, characterized in that: include: The acquisition unit is used to collect relevant parameters of the grid-connected system of the new energy station; A first calculation unit is configured to calculate a wide-band oscillation stability margin index of the new energy station grid connection using relevant parameters of the new energy station grid connection system; A judgment unit, configured to judge whether the grid-connected system of the new energy station needs to be optimized according to the broadband oscillation stability margin index of the grid-connected new energy station; The second calculation unit is used to calculate the participation factor of each converter access node in the new energy station grid-connected system by using the node impedance model of the new energy station grid-connected system when the new energy station grid-connected system needs to be optimized; an optimization configuration unit, configured to optimize the configuration of the grid-connected units of the new energy station grid-connected system according to the participation factors of the converter access nodes in the new energy station grid-connected system, and to recalculate the wide-band oscillation stability margin index of the new energy station grid-connected system until the new energy station grid-connected system reaches an optimal configuration; The second computing unit includes: A first acquisition module is configured to acquire a characteristic equation of the node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system; A second acquisition module is used to obtain the participation factor of each converter access node in the new energy station grid-connected system by using the characteristic equation of the node impedance model of the new energy station grid-connected system; The first acquisition module includes: A first determining submodule is configured to determine a denominator of a closed-loop transfer function of a node impedance model of the new energy station grid-connected system according to the node impedance model of the new energy station grid-connected system; A first acquisition submodule is configured to set the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system to zero, and simplify the function to obtain the characteristic equation of the node impedance model of the new energy station grid-connected system; The second acquisition module includes: The second acquisition submodule is used to convert the characteristic equation of the node impedance model of the new energy station grid-connected system into a solution for solving the determinant of the n+1 dimensional ordered impedance matrix using Schur complement transformation to obtain the model eigenvalue; A second determining submodule is configured to determine stability information and oscillation property information of the new energy station grid-connected system according to the model characteristic value; a calculation submodule, configured to calculate, when the new energy station grid-connected system is unstable, a participation factor of each converter access node in the new energy station grid-connected system under the oscillation mode corresponding to the model eigenvalue; The optimization configuration unit includes: The selection module is used to select the grid-following converter connected to the node with the largest participation factor from the participation factors of the converter access nodes in the new energy station grid-connected system, and replace it with a grid-forming converter of the same capacity.

13. The device according to claim 12, characterized in that The relevant parameters of the new energy station grid-connected system include: operating point parameters of the new energy station grid-connected system, network topology parameters of the new energy station grid-connected system and control parameters of the new energy power generation unit; The operating point parameters of the new energy station grid-connected system include: voltage signals and current signals of each node in the new energy station grid-connected system; The network topology parameters of the new energy station grid-connected system include: a node admittance matrix of the new energy station grid-connected system; The control parameters of the new energy power generation unit include: main circuit parameters and control parameters of the new energy power generation unit; The main circuit parameters include: rated capacity and rated voltage of the converter, filter inductance and filter capacitance in the converter main circuit; The control parameters include: control parameters of the power link, voltage link, current link and virtual impedance used in the converter controller.

14. The device according to claim 12, characterized in that The first computing unit includes: A first calculation module is configured to calculate the impedance ratio of the new energy station grid-connected system based on relevant parameters of the new energy station grid-connected system and using a pre-built new energy side aggregate impedance model; A second calculation module is configured to calculate a stability margin function of the new energy station grid-connected system using the impedance ratio of the new energy station grid-connected system; The third calculation module is used to calculate the wide-band oscillation stability margin index of the new energy station grid connection using the new energy station grid connection system stability margin function.

15. The device according to claim 14, characterized in that The calculation formula of the new energy side aggregation impedance model includes: The calculation formula for the grid-connected system impedance ratio of the new energy station includes: In the above formula, is the aggregate admittance of the new energy station, is the aggregate impedance of the new energy station, is the positive sequence admittance of the new energy station, The coupling admittance of the new energy station is calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at the grid connection point of the new energy station. The coupling admittance of the new energy station is calculated from the positive sequence voltage disturbance component and the negative sequence current disturbance component at the grid connection point of the new energy station. is the negative sequence admittance on the grid side, is the negative sequence admittance of the new energy station, s is the pull operator, s′ is the coupling frequency pull-down operator, is the impedance ratio of the grid-connected system of the new energy station, is the positive sequence impedance on the grid side.

16. The device according to claim 14, characterized in that The calculation formula of the new energy station grid-connected system stability margin function includes: In the above formula, is the impedance ratio of the grid-connected system of the new energy station, G(s) is the stability margin function of the grid-connected system of the new energy station, and s is the pull operator.

17. The device according to claim 14, characterized in that The calculation formula for the broadband oscillation stability margin index of the new energy station grid connection includes: In the above formula, γ is the broadband oscillation stability margin index of the new energy station grid connection, s = jω, G(jω) is the stability margin function of the new energy station grid connection system, j is the imaginary number sign, and ω is the angular frequency.

18. The device according to claim 12, characterized in that The judgment unit is specifically used to: Determine whether the broadband oscillation stability margin index of the new energy station grid-connected is greater than or equal to the margin threshold. If the broadband oscillation stability margin index of the new energy station grid-connected is greater than or equal to the margin threshold, the new energy station grid-connected system does not need to be optimized, and the current configuration of the new energy station grid-connected system is the optimal configuration; if the broadband oscillation stability margin index of the new energy station grid-connected is less than the margin threshold, the new energy station grid-connected system needs to be optimized.

19. The device according to claim 12, characterized in that The calculation formula of the node impedance model of the new energy station grid-connected system includes: In the above formula, s is the pull-type operator, s′ is the coupling frequency pull-down operator, is the n+1-dimensional positive sequence small signal current component, is the n+1-dimensional negative sequence small signal current component, is the positive sequence node admittance matrix of the network element, is the negative-sequence node admittance matrix of the network elements, is the positive sequence admittance diagonal matrix of the converter, is a diagonal matrix composed of the coupled admittances calculated from the negative sequence current disturbance component and the positive sequence voltage disturbance component at each node in the new energy station. is the diagonal matrix composed of the converter coupling admittance calculated from the positive sequence current disturbance component and the negative sequence voltage disturbance component at each node in the new energy station. is the negative sequence admittance diagonal matrix of the converter, is the n+1-dimensional positive sequence small signal voltage component, It is the n+1-dimensional negative-sequence small signal voltage component.

20. The device according to claim 12, characterized in that The calculation formula of the denominator of the closed-loop transfer function of the node impedance model of the new energy station grid-connected system includes: The calculation formula of the characteristic equation of the node impedance model of the new energy station grid-connected system includes: In the above formula, s is the pull operator, det(•) is the determinant solution, is the 2(n+1)-dimensional admittance matrix of the network element, is the 2(n+1)-dimensional admittance matrix of the converter.

21. The device according to claim 12, characterized in that The calculation formula for solving the determinant of the n+1-dimensional ordered impedance matrix includes: The calculation formula of the model characteristic value includes: In the above formula, s is the pull operator, det(•) is the determinant solution, For Solve the determinant, is the corrected equivalent positive sequence admittance of the new energy station grid-connected system, for The left eigenvector matrix of is the eigenvalue diagonal matrix, diag{·} is the diagonal matrix, λ n is the nth eigenvalue, λ n+1 is the n+1th eigenvalue, n+1 is the order of the matrix, for The right eigenvector matrix of .

22. The device according to claim 12, characterized in that The calculation formula for the participation factor of the converter access node in the new energy station grid-connected system includes: p i =L ik •T ik In the above formula, i is the converter access node in the new energy station grid-connected system, p i is the participation factor of the converter access node i in the new energy station grid-connected system, T ik To reflect the effect of the current injected by the converter access node i on the kth characteristic trajectory in the new energy station grid-connected system, L ik T ik The corresponding weight of the new energy station grid-connected system mode.

23. A computer device, characterized in that: include: at least one processor and memory; The memory is used to store one or more programs; When the one or more programs are executed by the at least one processor, the new energy station networking unit optimization configuration method according to any one of claims 1 to 11 is implemented.

24. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed, the method for optimizing the configuration of the network-type units of the new energy station as described in any one of claims 1 to 11 is implemented.

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