Heterogeneous new energy base rapid regulation and control method considering system strength constraint

Abstract

The invention discloses a system strength constraint-considered heterogeneous new energy base rapid regulation and control method, which comprises the following steps of: firstly, aiming at a new energy base heterogeneous system comprising diversified heterogeneous equipment, based on a generalized short-circuit ratio system strength index and a component weighting thought; establishing an evaluation architecture convenient for real-time monitoring of the stability margin of the heterogeneous system; a rapid regulation and control target for coping with sudden drop of system strength is characterized as a new energy output power maximization problem meeting system strength constraints, so that frequency drop cascading failures caused by excessive drop of new energy output are avoided while small-interference stable operation of the system is maintained; and finally, on the basis of a primal-dual gradient algorithm, constructing an online rapid regulation and control strategy of multi-station cooperative participation in the new energy base. The rapid regulation and control method not only can ensure enough system strength and effectively reduce the oscillation risk of the system, but also can optimize the output power of the new energy station and avoid frequency drop induced by a large amount of off-network of the unit, and has practical engineering significance.

Description

Technical Field

[0001] The present invention relates to the field of operation of new energy grid-connected systems, and in particular to a method for rapid control of heterogeneous new energy bases taking into account system strength constraints. Background Art

[0002] With the widespread integration of power electronics, such as renewable energy, and the corresponding withdrawal of traditional synchronous generators, the system strength of new power systems has significantly decreased, which can easily lead to stability issues such as static voltage instability and sub- / supersynchronous oscillations. During actual system operation, when events such as large deviations in renewable energy power forecasts or line outages trigger a sudden drop in system strength, this can lead to system instability and serious consequences.

[0003] Although there have been studies on rapid control of broadband oscillations, most of them are aimed at traditional power systems dominated by synchronous generators. For new power electronic power systems represented by large-scale diversified renewable energy bases, how to take appropriate rapid control measures to suppress the system safety and stability problems caused by sudden drops in system strength is still lacking. Lai Xiang et al. proposed a consensus-based cooperative control method based on grid strength measurement. However, this method is only applicable to the case where the external characteristics of each renewable energy device are the same, and the strength index used cannot be applied to the actual diversified renewable energy scenarios, which has limitations (Lai Xiang, Liu Yun, Zhang Xinan, et al. Grid Strength Constrained Cooperative Control of Renewable Power Plants for Guaranteed Small-Signal Stability [J]. IEEE Transactions on Power Systems, 2024, 39 (6): 7425-7428.).

[0004] Therefore, there is an urgent need for a rapid control method for heterogeneous new energy bases that takes into account system strength constraints. Focusing on diversified and heterogeneous new energy bases, while ensuring sufficient system strength, the overall output of each new energy station is maximized, thereby avoiding chain failures such as frequency drops that may be induced by excessive load shedding, and adaptively restoring the power delivery level of each new energy station after the system strength gradually recovers. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and propose a rapid control method for heterogeneous new energy bases that takes into account system strength constraints. First, for a new energy base grid-connected system (heterogeneous system) containing diverse heterogeneous equipment, an evaluation framework is established based on the generalized short-circuit ratio system strength index and component weighting to facilitate real-time monitoring of the stability margin of the heterogeneous system. Then, the rapid control target for responding to sudden drops in system strength is characterized as the problem of maximizing the output power of renewable energy sources that meets the system strength constraint. This method maintains stable operation of the system with small disturbances while avoiding excessive output reduction of renewable energy sources that could induce a cascading frequency drop failure. Finally, an online rapid control strategy for the coordinated participation of multiple stations in the new energy base is constructed based on the original dual subgradient algorithm. This rapid control method not only ensures sufficient system strength and effectively reduces the risk of system oscillation, but also optimizes the output power of renewable energy stations and avoids frequency drops caused by a large number of units being disconnected from the grid, thus having practical engineering significance.

[0006] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0007] A method for rapid control of a heterogeneous new energy base taking into account system strength constraints includes the following steps:

[0008] S1. Establish a closed-loop characteristic equation for a heterogeneous system of a new energy base that includes diverse heterogeneous equipment, where the new energy system is divided into an AC network part and a new energy station part;

[0009] S2. Establish the generalized short-circuit ratio and critical generalized short-circuit ratio of heterogeneous systems, use the generalized short-circuit ratio as a grid strength indicator, and use the critical generalized short-circuit ratio as a critical stability indicator for renewable energy multi-feed systems;

[0010] S3. Establish a fast calculation method for the critical generalized short-circuit ratio of heterogeneous systems to facilitate real-time evaluation, operation control and optimization of the system;

[0011] S4. Establish a system output power optimization model under small disturbance stability constraints;

[0012] S5. Construct an online collaborative rapid control method based on the optimization model to optimize the renewable energy power reduction rate when the system strength drops, while avoiding the sub / supersynchronous oscillation divergence caused by weak power grids and the frequency drop caused by a large number of units being disconnected from the grid.

[0013] Furthermore, the closed-loop characteristic equation of the heterogeneous system in step S1 is:

[0014]

[0015] Among them, deg{.} is the determinant of the matrix, Y GFLC (s) is the impedance transfer function matrix of the station, s is the Laplace operator, diag{.} is a matrix with all zeros outside the main diagonal, Gi (s) is the port admittance transfer function of the i-th station observed in the synchronous rotating coordinate system, that is, the response of the current to the voltage disturbance, P i and U i Represent the active power and port voltage of the i-th station respectively, B r is the Krona-reduced node admittance matrix after removing the passive busbar and infinite busbar, is the transmission line admittance matrix, and ω0 is the synchronous stable angular frequency.

[0016] Furthermore, in step S1, the AC network portion includes equivalent impedances and Thevenin equivalent voltage sources between nodes. The linearized model of the AC network side can be expressed as:

[0017]

[0018] in, is the transmission line admittance matrix, ω0 is the synchronous stable angular frequency, represents the Kronecker product, B r is the Krona reduced node admittance matrix after removing the passive busbar and infinite busbar, s is the Laplace operator, ΔI and ΔU are the micro increments of the port current and voltage respectively, and Y net (s) is the impedance transfer function matrix of the AC power grid.

[0019] Furthermore, in step S1, the new energy station includes various new energy sources such as photovoltaics and wind turbines, as well as a DC converter station and its control system. The linearized model on the station side is:

[0020]

[0021] Among them G i (s) is the port admittance transfer function of the i-th station observed in the synchronous rotating coordinate system, that is, the response of the current to the voltage disturbance. s is the Laplace operator, diag{.} is a matrix with all zeros outside the main diagonal, ΔI and ΔU are the micro-increments of the port current and voltage, respectively, and P i and U i Represent the active power and port voltage of the i-th station respectively, Y GFLC (s) is the impedance transfer function matrix of the station.

[0022] Furthermore, in step S2, a generalized short-circuit ratio of the heterogeneous system is established, specifically as follows:

[0023] Based on the matrix perturbation theory, an equivalent isomorphic system of heterogeneous systems is constructed, and the characteristic equation is:

[0024]

[0025] Among them, the port admittance transfer function p 1i =v 1l u l1 For the i-th station Participation factor of the smallest eigenvalue, G i (s) is the port admittance transfer function of the i-th station observed in the synchronous rotating coordinate system, that is, the response of the current to the voltage disturbance, v 1l and u l1 They are matrices Regarding the left eigenvector and the lth element of the right eigenvector of the minimum eigenvalue, diag{.} is a matrix with all zeros outside the main diagonal, P i and U i Represent the active power and port voltage of the i-th station respectively, B r is the Krone-reduced node admittance matrix after removing the passive busbar and infinite busbar; n represents the total number of stations in the system;

[0026] The matrix The minimum eigenvalue of is defined as the generalized short-circuit ratio:

[0027]

[0028] Where minλ(.) is the minimum eigenvalue of the matrix, and gSCR is the generalized short-circuit ratio.

[0029] Furthermore, in step S2, the critical generalized short-circuit ratio is established as follows:

[0030] The critical generalized short-circuit ratio, that is, the generalized short-circuit ratio when the dominant eigenvalue of the system is exactly on the imaginary axis of the complex plane, is:

[0031]

[0032] Where CgSCR is the critical generalized short-circuit ratio, arg{.} is the eigenvalue solution of the equation, det{.} is the determinant of the matrix, j is the imaginary unit, ω is the angular frequency, s = jω indicates that the dominant eigenvalue lies on the imaginary axis in the complex plane, gSCR is the generalized short-circuit ratio, F(jω) is the line transmission equation, and G(jω) is the port admittance transfer function.

[0033] Furthermore, in step S3, a fast calculation method for the critical generalized short-circuit ratio of a heterogeneous system is established, specifically as follows:

[0034] The critical short-circuit ratio of the station is:

[0035]

[0036] Where SCR is the station short circuit ratio, and the critical short circuit ratio CSCR of the i-th station is iIt can characterize the station's tolerance to weak power grids, det{.} is the determinant of the matrix, j is the imaginary unit, ω is the angular frequency, F(jω) is the line transmission equation, and G(jω) is the port admittance transfer function;

[0037] A simplified fast calculation method for critical generalized short-circuit ratio for heterogeneous systems is established:

[0038]

[0039] where p 1i Indicates the i-th station about The participation factor of the smallest eigenvalue, diag{.} is a matrix with all zeros outside the main diagonal, P i and U i Represent the active power and port voltage of the i-th station respectively, B r is the Krona reduced node admittance matrix after removing the passive busbar and infinite busbar; CgSCR r represents the critical generalized short-circuit ratio.

[0040] Furthermore, in step S4, establishing a system output power optimization model under small disturbance stability constraints includes:

[0041]

[0042] gSCR-CgSCR r ≥Δ

[0043] Among them, P i is the output power of the i-th station, P i max is the maximum available power of the station, Δ is the set system strength margin, n is the total number of stations in the system; gSCR and CgSCR r are the generalized short-circuit ratio and the critical generalized short-circuit ratio, respectively. The constraints can ensure the small-disturbance stability of the new energy system.

[0044] Furthermore, in step S5, the online collaborative rapid control method is constructed as follows:

[0045] The augmented Lagrangian function for the optimization problem is:

[0046]

[0047] Where L is the augmented Lagrangian function, μ is the multiplier, ρ is the penalty factor, 0<P i <P i max , P i is the output power of the i-th station, P i maxis the maximum available power of the station, gSCR and CgSCR r are the generalized short circuit ratio and the critical generalized short circuit ratio respectively, Δ is the set system strength margin, and L μ Denotes the augmented Lagrangian function P i And the partial derivative of the multiplier μ, then:

[0048]

[0049] The sensitivity of the generalized short-circuit ratio to the output power of station i is:

[0050] s i =-gSCR×(u l1 ) 2

[0051] where s i is the sensitivity, u l1 yes Regarding the lth element of the right eigenvector of the minimum eigenvalue, diag{.} is a matrix with all zeros outside the main diagonal, P i and U i Represent the active power and port voltage of the i-th station respectively, B r is the Krone-reduced node admittance matrix after removing the passive busbar and infinite busbar;

[0052] Update P i The detailed iterative method for calculating the state at time k+1 from the state at time k is as follows:

[0053]

[0054] Where a is the iteration step size, ρ is the penalty factor, P i (k) and μ (k) are the output power and multiplier of station i at time k, CgSCR r (k) and gSCR (k) are the critical generalized short-circuit ratio and generalized short-circuit ratio calculated at time k, respectively, and Δ is the set system strength margin; L μ They represent the augmented Lagrangian function of P i and the partial derivative with respect to the multiplier μ; s i (k) represents the sensitivity of the generalized short-circuit ratio at time k to the output power of station i;

[0055] Selecting the step size a so that the iteration can converge, we have:

[0056] lim k→∞ (CgSCRr (k) +Δ-gSCR (k) )=0

[0057]

[0058] Among them, P * Indicates the convergence value of the sum of output powers;

[0059] When the fault disappears, the stability margin is monitored to increase suddenly, that is, gSCR-CgSCR r ≥δ, where δ is a stability margin value greater than Δ, and the system automatically recovers to the power state before the fault.

[0060] A computer device of the present invention includes: a memory and a processor and a computer program stored in the memory. When the computer program is executed on the processor, the method for rapid control of heterogeneous new energy bases taking into account system strength constraints is implemented.

[0061] Compared with the prior art, the present invention's method for rapid control of heterogeneous new energy bases taking into account system strength constraints has the following beneficial effects:

[0062] (1) In the event of a sudden drop in system strength caused by large deviations in renewable energy power forecasts or line outages, the system can effectively reduce the risk of system oscillations, while avoiding excessive power reduction in renewable energy that may induce a frequency drop chain failure, making it safer and more stable.

[0063] (2) It has good scalability. The method of the present invention can adapt to the rapid regulation of different types of new energy bases. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 The flowchart of the embodiment for obtaining the rapid control results of the new energy base.

[0065] Figure 2 This is a schematic diagram of the test network structure for the example simulation of the present invention.

[0066] Figure 3 It is a structural diagram of the new energy base grid-connected system of the present invention. DETAILED DESCRIPTION

[0067] In order to make the objectives, technical solutions and advantages of the present invention more clear and explicit, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0068] Example 1

[0069] This example is a fast control method for heterogeneous new energy bases taking into account system strength constraints, such as Figure 1As shown, this example uses a modified IEEE 39-node power system for testing to specifically illustrate a fast control method for heterogeneous new energy bases taking into account system strength constraints provided by the present invention. The grid-connected converter control structure and power network topology are shown in FIG. Figure 2 and Figure 3 As shown, the following steps are included:

[0070] In this embodiment, the control parameters of each link of the grid-connected converter in the IEEE 39-bus system are obtained, and their specific values ​​are shown in Table 1, as well as the power network line parameters, and their specific values ​​are shown in Table 2.

[0071] Table 1 IEEE 39-bus system grid-following converter control parameters

[0072]

[0073] Table 2 IEEE 39-bus system power network parameters

[0074]

[0075]

[0076]

[0077] S1. Establish a closed-loop characteristic equation for a new energy base grid-connected system (heterogeneous system) that includes diverse heterogeneous equipment.

[0078] like Figure 3 As shown in Figure 1, the new energy system can be divided into two parts: the AC network and the new energy station. The AC network part includes the equivalent impedance between each node and the Thevenin equivalent voltage source. The linearized model of the AC network side can be expressed as:

[0079]

[0080] in, is the transmission line admittance matrix, ω0 is the synchronous stable angular frequency, represents the Kronecker product, B r is the Krona reduced node admittance matrix after removing the passive busbar and infinite busbar, s is the Laplace operator, ΔI and ΔU are the micro increments of the port current and voltage respectively, and Y net (s) is the impedance transfer function matrix of the AC power grid.

[0081] The new energy station part includes various new energy sources such as photovoltaics, wind turbines, and DC converter stations and their control systems. The linearized model of the station side can be written as:

[0082]

[0083] Among them Gi (s) is the port admittance transfer function of the i-th station observed in the synchronous rotating coordinate system, that is, the response of current to voltage disturbance. diag{.} is a matrix with all zeros outside the main diagonal. ΔI and ΔU are the micro-increments of port current and voltage, respectively. P i and U i Represent the active power and port voltage of the i-th station respectively, Y GFLC (s) is the impedance transfer function matrix of the station.

[0084] Establish a closed-loop characteristic equation for a new energy base grid-connected system (heterogeneous system) that includes diverse heterogeneous equipment:

[0085]

[0086] Where det{.} is the determinant of the matrix.

[0087] S2. Establish the generalized short-circuit ratio of heterogeneous systems and use the generalized short-circuit ratio as a grid strength indicator, as follows:

[0088] Based on the matrix perturbation theory, an equivalent isomorphic system of heterogeneous systems is constructed, and the characteristic equation is:

[0089]

[0090] in, p 1i For the i-th station about the matrix The participation factor of the minimum eigenvalue characterizes the impact of a single device on the stability of the multi-infeed system.

[0091] If the dominant characteristic trajectory of the heterogeneous system is approximately equal to the dominant characteristic trajectory of its equivalent isomorphic system, then the stability analysis of the equivalent isomorphic system can be used as the stability analysis result of the heterogeneous system. Therefore, the small-disturbance stability of the heterogeneous system depends on the grid strength of the weakest equivalent single-feed system, which is given by It can be seen that the small disturbance stability of the heterogeneous system is represented by The minimum eigenvalue of .

[0092] The matrix The minimum eigenvalue of is defined as the generalized short-circuit ratio:

[0093]

[0094] Where minλ(.) is the minimum eigenvalue of the matrix, gSCR is the generalized short-circuit ratio;

[0095] The critical generalized short-circuit ratio is used as the critical stability indicator of the renewable energy multi-feed system, as follows:

[0096] The critical generalized short-circuit ratio, that is, the generalized short-circuit ratio when the dominant eigenvalue of the system is exactly on the imaginary axis of the complex plane is:

[0097]

[0098] Where CgSCR is the critical generalized short-circuit ratio, arg{.} is the eigenvalue solution of the equation; jω represents the imaginary axis on the complex plane where the dominant eigenvalue lies, and F(jω) is the line transmission equation. Therefore, the critical generalized short-circuit ratio can be used to quantify the stability boundary of a multi-infeed system, i.e., the threshold for identifying small-disturbance stability issues through system strength assessment.

[0099] S3. Establish a fast calculation method for the critical generalized short-circuit ratio of heterogeneous systems, as follows:

[0100] The critical short-circuit ratio of the station is:

[0101]

[0102] Among them, SCR is the station short circuit ratio, and CSCR is the station critical short circuit ratio. i It can characterize the station's ability to withstand weak power grids. Its value depends on the station's own control strategy and parameters, so it can be considered known and unchanged. r Can be regarded as CSCR of each station i The weight reflects the influence of each station on the stability of the system with small disturbances. The participation factor p can be selected 1i Based on this, a simplified calculation method for the critical generalized short-circuit ratio that can be used in heterogeneous systems is established:

[0103]

[0104] In heterogeneous systems, the critical generalized short-circuit ratio CgSCR of the system obtained by the proposed fast calculation method is r The CgSCR obtained by traditional trial and error can be approximated within an acceptable error, so when this fast calculation method is applied to power grid planning or operation control, the error generated by the approximation can be regarded as an additional system stability margin, which can be more conveniently applied to real-time evaluation, operation control and optimization of the system, and make the results more robust.

[0105] S4. Establish small disturbance stability constraints:

[0106] gSCR-CgSCR r =δ0≥Δ

[0107] Among them, δ0 is used to characterize the stability margin of the heterogeneous system; Δ is the set system strength margin; gSCR and CgSCR r are the generalized short-circuit ratio and the critical generalized short-circuit ratio, respectively. This constraint can ensure the small-disturbance stability of the new energy system.

[0108] Establish a system output power optimization model under small disturbance stability constraints:

[0109]

[0110] gSCR-CgSCR r ≥Δ

[0111] Among them, P i is the output power of the i-th station, P i max is the maximum available power of the station, Δ is the set system strength margin, gSCR and CgSCR r Can be regarded as P i function.

[0112] S5. Construct a rapid control method for heterogeneous new energy bases. Based on the calculated values ​​of generalized short-circuit ratio and critical generalized short-circuit ratio, the system's small-disturbance stability margin is monitored online. When a sudden drop in the stability margin is detected, rapid control is performed, and automatic recovery is performed when the fault disappears. The details are as follows:

[0113] The augmented Lagrangian function of the optimization problem is:

[0114]

[0115] Where L is the augmented Lagrangian function, μ is the multiplier, ρ is the penalty factor, 0<P i <P i max .by L μ Denotes the augmented Lagrangian function for the decision variable P i And the partial derivative of the multiplier μ, then:

[0116]

[0117] Under different working conditions of the same system, the critical generalized short-circuit ratio changes little, so it can be seen that The value of is small enough, and considering that the calculation is relatively complicated, the control method can be designed Approximately 0. i It represents the sensitivity of the generalized short-circuit ratio to the output power of station i, that is, Proven (Lai Xiang, Liu Yun, Zhang Xinan, et al. Grid Strength Constrained Cooperative Control of RenewablePower Plants for Guaranteed Small-Signal Stability[J]. IEEE Transactions on Power Systems, 2024, 39(6):7425-7428.):

[0118] s i =-gSCR×(u l1 ) 2

[0119] where s i is the sensitivity, u l1 yes The lth element of the right eigenvector about the smallest eigenvalue.

[0120] Update the original variable P i The detailed iterative method for calculating the state at time k+1 from the state at time k is as follows:

[0121]

[0122] μ (k+1) =μ (k) +aL μ

[0123] =μ (k) +a(CgSCR r (k) +Δ-gSCR (k) )

[0124] Where a is the iteration step size, ρ is the penalty factor, P i (k) and μ (k) are the output power and multiplier of station i at time k, CgSCR r (k) and gSCR (k) are the critical generalized short-circuit ratio and generalized short-circuit ratio calculated at time k, respectively.

[0125] When the step size a is selected appropriately, the iteration can converge, and we have:

[0126] lim k→∞ (CgSCR r (k) +Δ-gSCR (k) )=0

[0127]

[0128] Among them, P * Represents the convergence value of the sum of the output power. When the results of the two iterations satisfy the following formula, the output power is quickly regulated and converges to the optimal solution:

[0129] ||P i (k+1) -P i (k) ||≤ε,i=1,2,...,n

[0130] Where ε is the convergence error.

[0131] When the fault disappears, the stability margin is monitored to increase suddenly, that is, gSCR-CgSCR r ≥δ, where δ is a stability margin value greater than Δ, and the system automatically recovers to the power state before the fault.

[0132] In the embodiment, ε=10 -3 , P i max =2p.u., Δ=0.1, a=0.8, ρ=0.1. During operation, the reactance of line (23, 36) was doubled to simulate a line fault that causes a decrease in system strength. A converged solution was obtained, which includes the corresponding output of each renewable energy station and the total output power results, as shown in Table 3.

[0133] Table 3 Results of rapid control of the new energy base after a fault occurs in Example 1

[0134]

[0135] For the results in Table 3, the convergence error is satisfied, and the set stability margin is satisfied (indicating that the system meets the requirement of small disturbance stability).

[0136] Example 2

[0137] In Example 2, the power network line parameters and control parameters of the new energy grid-connected system remain unchanged; the maximum output power P of the station i max It is changed to 2.5pu, and the stability margin is set to be the same as the fault scenario.

[0138] The results of rapid control of the new energy base in Example 2 are shown in Table 4.

[0139] Table 4 Evaluation results of the maximum carrying capacity of the new energy base in Example 2

[0140]

[0141] The results in Table 4 satisfy the convergence error and the set stability margin (indicating that the system meets the requirements for small-disturbance stability). The results in Table 4 indicate that the maximum output power limit will affect the rapid control results of the new energy station.

[0142] Example 3

[0143] In Example 3, the power network line parameters and control parameters of the new energy grid-connected system remain unchanged; the reactance of the line (23, 36) where the fault occurs is set to increase by 0.5 times, and the stability margin and maximum output power are set to be the same.

[0144] The evaluation results of the maximum carrying capacity of the new energy base in Example 3 are shown in Table 5.

[0145] Table 5 Evaluation results of the maximum carrying capacity of the new energy base in Example 3

[0146]

[0147] The results in Table 5 satisfy the convergence error and the set stability margin (indicating that the system meets the requirements for small-disturbance stability). From the results in Table 5, we can see that different fault levels will affect the rapid control results of the new energy station.

[0148] Obviously, the above-described embodiments merely represent several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, and such modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A rapid control method for heterogeneous new energy bases taking into account system strength constraints, characterized by: The following steps are involved: S1. Establish a closed-loop characteristic equation for a heterogeneous system of a new energy base that includes diverse heterogeneous equipment, where the new energy system is divided into an AC network part and a new energy station part; S2. Establish the generalized short-circuit ratio and critical generalized short-circuit ratio of heterogeneous systems, use the generalized short-circuit ratio as a grid strength indicator, and use the critical generalized short-circuit ratio as a critical stability indicator for renewable energy multi-feed systems; S3. Establish a fast calculation method for the critical generalized short-circuit ratio of heterogeneous systems to facilitate real-time evaluation, operation control and optimization of the system; S4. Establish a system output power optimization model under small disturbance stability constraints; S5. Construct an online collaborative rapid control method based on the optimization model to optimize the renewable energy power reduction rate when the system strength drops, while avoiding the sub / supersynchronous oscillation divergence caused by weak power grids and the frequency drop caused by a large number of units being disconnected from the grid.

2. A method for rapid control of heterogeneous new energy bases taking into account system strength constraints according to claim 1, characterized in that: The closed-loop characteristic equation of the heterogeneous system in step S1 is: Among them, det{.} is the determinant of the matrix, Y GFLC (s) is the impedance transfer function matrix of the station, s is the Laplace operator, diag{.} is a matrix with all zeros outside the main diagonal, G i (s) is the port admittance transfer function of the i-th station observed in the synchronous rotating coordinate system, that is, the response of the current to the voltage disturbance, P i and U i Represent the active power and port voltage of the i-th station respectively, B r is the Krona-reduced node admittance matrix after removing the passive busbar and infinite busbar, is the transmission line admittance matrix, and ω0 is the synchronous stable angular frequency.

3. The method for rapid control of heterogeneous new energy bases taking into account system strength constraints according to claim 1 is characterized in that: In step S1, the AC network part includes equivalent impedances between nodes and Thevenin equivalent voltage sources. The linearized model of the AC network side can be expressed as: in, is the transmission line admittance matrix, ω0 is the synchronous stable angular frequency, represents the Kronecker product, B r is the Krona reduced node admittance matrix after removing the passive busbar and infinite busbar, s is the Laplace operator, ΔI and ΔU are the micro increments of the port current and voltage respectively, and Y net (s) is the impedance transfer function matrix of the AC power grid.

4. The method for rapid control of heterogeneous new energy bases taking into account system strength constraints according to claim 1 is characterized in that: In step S1, the new energy station includes various new energy sources such as photovoltaics and wind turbines, as well as a DC converter station and its control system. The linearized model on the station side is: Among them G i (s) is the port admittance transfer function of the i-th station observed in the synchronous rotating coordinate system, that is, the response of the current to the voltage disturbance. s is the Laplace operator, diag{.} is a matrix with all zeros outside the main diagonal, ΔI and ΔU are the micro-increments of the port current and voltage, respectively, and P i and U i Represent the active power and port voltage of the i-th station respectively, Y GFLC (s) is the impedance transfer function matrix of the station.

5. The method for rapid control of heterogeneous new energy bases taking into account system strength constraints according to claim 1 is characterized in that: In step S2, a generalized short-circuit ratio of the heterogeneous system is established, specifically as follows: Based on the matrix perturbation theory, an equivalent isomorphic system of heterogeneous systems is constructed, and the characteristic equation is: Among them, the port admittance transfer function p 1i =v 1l u l1 For the i-th station Participation factor of the smallest eigenvalue, G i (s) is the port admittance transfer function of the i-th station observed in the synchronous rotating coordinate system, that is, the response of the current to the voltage disturbance, v 1l and u l1 They are matrices Regarding the left eigenvector and the lth element of the right eigenvector of the minimum eigenvalue, diag{.} is a matrix with all zeros outside the main diagonal, P i and U i Represent the active power and port voltage of the i-th station respectively, B r is the Krone-reduced node admittance matrix after removing the passive busbar and infinite busbar; n represents the total number of stations in the system; The matrix The minimum eigenvalue of is defined as the generalized short-circuit ratio: Where minλ(.) is the minimum eigenvalue of the matrix, and gSCR is the generalized short-circuit ratio.

6. The method for rapid control of heterogeneous new energy bases taking into account system strength constraints according to claim 1 is characterized in that: In step S2, the critical generalized short-circuit ratio is established as follows: The critical generalized short-circuit ratio, that is, the generalized short-circuit ratio when the dominant eigenvalue of the system is exactly on the imaginary axis of the complex plane, is: Where CgSCR is the critical generalized short-circuit ratio, arg{.} is the eigenvalue solution of the equation, det{.} is the determinant of the matrix, j is the imaginary unit, ω is the angular frequency, s = jω indicates that the dominant eigenvalue lies on the imaginary axis in the complex plane, gSCR is the generalized short-circuit ratio, F(jω) is the line transmission equation, and G(jω) is the port admittance transfer function.

7. The method for rapid control of heterogeneous new energy bases taking into account system strength constraints according to claim 1 is characterized in that: In step S3, a fast calculation method for the critical generalized short-circuit ratio of a heterogeneous system is established, specifically as follows: The critical short-circuit ratio of the station is: Where SCR is the station short circuit ratio, and the critical short circuit ratio CSCR of the i-th station is i It can characterize the station's tolerance to weak power grids, det{.} is the determinant of the matrix, j is the imaginary unit, ω is the angular frequency, F(jω) is the line transmission equation, and G(jω) is the port admittance transfer function; A simplified fast calculation method for critical generalized short-circuit ratio for heterogeneous systems is established: where p 1i Indicates the i-th station about The participation factor of the smallest eigenvalue, diag{.} is a matrix with all zeros outside the main diagonal, P i and U i Represent the active power and port voltage of the i-th station respectively, B r is the Krona reduced node admittance matrix after removing the passive busbar and infinite busbar; CgSCR r represents the critical generalized short-circuit ratio.

8. The method for rapid control of heterogeneous new energy bases taking into account system strength constraints according to claim 1 is characterized in that: In step S4, establishing a system output power optimization model under small disturbance stability constraints includes: Among them, P i is the output power of the i-th station, is the maximum available power of the station, Δ is the set system strength margin, n is the total number of stations in the system; gSCR and CgSCR r are the generalized short-circuit ratio and the critical generalized short-circuit ratio, respectively. The constraints can ensure the small-disturbance stability of the new energy system.

9. A method for rapid control of heterogeneous new energy bases taking into account system strength constraints according to any one of claims 1 to 8, characterized in that: In step S5, the online collaborative rapid control method is constructed as follows: The augmented Lagrangian function for the optimization problem is: Where L is the augmented Lagrangian function, μ is the multiplier, and ρ is the penalty factor. P i is the output power of the i-th station, is the maximum available power of the station, gSCR and CgSCR r are the generalized short circuit ratio and the critical generalized short circuit ratio respectively, Δ is the set system strength margin, and L μ Denotes the augmented Lagrangian function P i And the partial derivative of the multiplier μ, then: The sensitivity of the generalized short-circuit ratio to the output power of station i is: with i =-gSCR×(u l1 ) 2 where s i is the sensitivity, Regarding the lth element of the right eigenvector of the minimum eigenvalue, diag{.} is a matrix with all zeros outside the main diagonal, P i and U i Represent the active power and port voltage of the i-th station respectively, B r is the Krone-reduced node admittance matrix after removing the passive busbar and infinite busbar; Update P i The detailed iterative method for calculating the state at time k+1 from the state at time k is as follows: Where a is the iteration step size, ρ is the penalty factor, and μ (k) are the output power and multiplier of station i at time k, CgSCR r (k) and gSCR (k) are the critical generalized short-circuit ratio and generalized short-circuit ratio calculated at time k, respectively, and Δ is the set system strength margin; L μ They represent the augmented Lagrangian function of P i and the partial derivative with respect to the multiplier μ; represents the sensitivity of the generalized short-circuit ratio at time k to the output power of station i; Selecting the step size a so that the iteration can converge, we have: lim k→∞ (CgSCR r (k) +Δ-gSCR (k) )=0 Among them, P * Indicates the convergence value of the sum of output powers; When the fault disappears, the stability margin is monitored to increase suddenly, that is, gSCR-CgSCR r ≥δ, where δ is a stability margin value greater than Δ, and the system automatically recovers to the power state before the fault.

10. A computer device, characterized in that: include: A memory, a processor, and a computer program stored in the memory. When the computer program is executed on the processor, a method for rapid control of a heterogeneous new energy base taking into account system strength constraints as described in claim 9 is implemented.

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