Networking type energy storage capacity configuration method for improving short-circuit ratio of new energy station

Abstract

The invention discloses a network construction type energy storage capacity configuration method for improving the short-circuit ratio of a new energy station, and belongs to the field of energy storage planning configuration. According to the method, the new energy multi-station short-circuit ratio of each new energy station is compared with the target new energy multi-station short-circuit ratio to determine whether source-side network-building type energy storage needs to be configured in the new energy station, and according to node information needing to be configured, a multi-target optimization algorithm is used to further determine source-side and network-side network-building type energy storage capacity; and the new energy multi-station short-circuit ratio of each node reaches the target new energy multi-station short-circuit ratio. According to the method, new energy multi-station short-circuit ratio calculation of the high-proportion new energy power system under different node configuration networking type energy storage of the multiple new energy stations is achieved, by planning source side networking type energy storage and network side networking type energy storage capacity configuration, the multi-new energy station short-circuit ratio is optimized, and the stability of the high-proportion new energy power system is improved.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage planning and configuration, and relates to a grid-type energy storage capacity configuration method for improving the short-circuit ratio of new energy sites. Background Art

[0002] With the urgent need for energy transformation and the opportunities brought by the rapid development of new energy power generation technology, the proportion of new energy sites connected to the grid continues to rise. New energy power generation is gradually becoming a research hotspot in the current power field due to its flexible, efficient and sustainable power generation methods. With the increase in the penetration rate of new energy in the power grid, the large-scale access of power electronics has made the dynamic characteristics of the power system more complex, and power quality problems such as harmonics, reactive power, and three-phase imbalance have become increasingly prominent, seriously threatening the safety and stability of the power grid. Since a large number of new energy grid-connected control methods are currently grid-following type, referred to as grid-following type, after being connected to the grid, they behave as controllable current sources and cannot be used as voltage sources to construct the AC voltage frequency characteristics of the power system like traditional synchronous machines. For new energy bases far away from the load center and lacking synchronous power support, their short circuit is lower than that of traditional power supplies, the grid strength is weak, and they show low anti-interference and weak support. The voltage stability margin and dynamic voltage support capacity are greatly reduced compared with the traditional thermal power-dominated system. The use of grid-connected energy storage is an effective solution to the above problems. After being connected to the grid, it behaves as a voltage source with voltage building, frequency and inertia support functions. The access of grid-connected energy storage can effectively improve the short-circuit current level of the new energy grid-connected system, thereby increasing the short-circuit ratio of the new energy site.

[0003] The application scenarios of energy storage can be divided into power supply side energy storage and grid side energy storage. Since the power supply side energy storage and grid side energy storage are connected to different locations and have different coordinated objects, there are certain differences in the way they cooperate with new energy and loads, resulting in different performance characteristics. The power supply side and grid side grid-type energy storage connected to the power system have different effects on improving the short-circuit ratio and voltage stability of new energy. With the construction of new energy stations and energy storage stations, power supply side grid-type energy storage and grid side grid-type energy storage will exist at the same time. If the capacity of the two is not reasonably configured, it may lead to a degradation of system stability and reduce the support effect of the power grid. Therefore, improving the short-circuit ratio of new energy stations by optimizing the capacity configuration of grid-type energy storage is one of the important technical topics of the present invention. Summary of the invention

[0004] The purpose of the present invention is to propose a grid-connected energy storage capacity configuration method for improving the short-circuit ratio of renewable energy sites, so as to improve the stability of a high-proportion renewable energy power system by optimizing the short-circuit ratio of renewable energy sites.

[0005] The present invention is realized by the following technical scheme. A method for configuring the capacity of a grid-type energy storage system to improve the short-circuit ratio of a new energy station, determining the number of new energy stations and then determining the number of nodes, determining the nominal voltage of each node, and determining the short-circuit ratio of each new energy station in the initial state according to the impedance parameters and the capacity of the new energy station in the power grid architecture; comparing the short-circuit ratio of each new energy station with the target short-circuit ratio of the new energy station; if it is greater than the target short-circuit ratio of the new energy station, there is no need to configure the grid-type energy storage system for this new energy station; if it is less than the target short-circuit ratio of the new energy station, it is necessary to configure the source-side grid-type energy storage system for this new energy station, and according to the node information to be configured, a multi-objective optimization algorithm is used to further determine the source-side and grid-side grid-type energy storage capacities; finally, the short-circuit ratio of the new energy station of each node reaches the target short-circuit ratio of the new energy station.

[0006] Further optimization, the short-circuit ratio of the new energy multi-station at node i before the grid-connected energy storage is calculated as follows:

[0007]

[0008] Where: S ACi 、E i , U Ni , U i ,I i They represent the short-circuit capacity, AC system equivalent potential, nominal voltage, voltage amplitude, and current amplitude of node i respectively. j is the voltage amplitude at node j, S EQi represents the equivalent grid-connected capacity of node i considering the mutual influence between the feed-in branches of other renewable energy stations, S REi represents the new energy capacity injected into node i, S REi represents the new energy capacity injected into node i, Z EQii , Z EQij Represents the system equivalent node impedance matrix Z EQ The self-impedance and mutual impedance of the corresponding nodes.

[0009] Further optimization, the short-circuit ratio of the new energy station at node i after the grid-connected energy storage is becomes:

[0010]

[0011] Where S Mi With S Mj is the source-side grid-connected energy storage capacity at nodes i and j, The node impedance matrix of the new energy multi-feed system after the grid-type energy storage is connected to the source-grid side The i-th row and j-th column element in S REi With SREj is the capacity of the new energy connected to nodes i and j, The node impedance matrix of the new energy multi-feed system after the grid-type energy storage is connected to the source-grid side The i-th row and i-th column element in E P is the grid-side grid-type energy storage equivalent potential, E Si is the equivalent potential of the source-side grid-type energy storage to node i, Z si is the equivalent impedance of the source-side grid-type energy storage to node i; E is the equivalent power supply.

[0012] Further preferably, the short-circuit capacity at node i after the grid-connected energy storage is connected is calculated as follows:

[0013]

[0014] Among them, f MRSCRi (S Mi ,S MP ) is the short-circuit capacity at node i after the grid-connected energy storage is connected, and S is the source-side grid-connected energy storage capacity S at node i. Mi And the grid-side grid-type energy storage capacity S MP The function of S MP It is the grid-type energy storage capacity for the grid side.

[0015] For further optimization, the short-circuit ratio of new energy multiple stations at each node is taken as the optimization target, and the capacity of the grid-connected energy storage connected to each node is taken as the optimization independent variable. The objective function of the grid-connected energy storage configuration capacity optimization model is established, the target short-circuit ratio of new energy multiple stations is set for each node, and the Pareto multi-objective optimization method is used to obtain the grid-connected energy storage configuration capacity of each new energy station and network hub node.

[0016] Further optimization, the objective function of the grid-type energy storage configuration capacity optimization model is:

[0017]

[0018] MRSCR obj is the MRSCR target value. The short-circuit ratio of the new energy multi-station after the grid-type energy storage configuration should be greater than or equal to the original MRSCR. Therefore, the constraint condition is:

[0019] f MRSCRi (S Mi ,S MP )≥MRSCR obj (16).

[0021] Further preferably, the maximum short-circuit capacity provided by the grid-connected energy storage under overload current limiting conditions will not exceed the short-circuit capacity under non-current limiting conditions, so the constraint condition is:

[0022]

[0023] Through the multi-objective optimization function established by equations (15)-(17) and the corresponding constraints, the corresponding relationship between the short-circuit ratio of multiple renewable energy stations and the capacity of renewable energy stations is utilized to optimize the short-circuit ratio of each renewable energy station and configure the capacity of the grid-type energy storage.

[0024] The present invention changes the short-circuit ratio of multiple new energy stations after the access of grid-type energy storage from the two perspectives of improving short-circuit capacity and changing the grid structure. The optimization goal is to improve the short-circuit ratio of each new energy station in the system to have a higher stability margin. The capacity of the grid-type energy storage station is used as the decision variable, and a multi-objective optimization model is established to determine the optimal configuration capacity of the source-side grid-type energy storage and the grid-side grid-type energy storage, thereby improving the system stability under large-scale new energy access. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the grid topology diagram of the system with multiple renewable energy inputs.

[0026] Figure 2 It is a multi-port Thevenin equivalent node model.

[0027] Figure 3 This is the grid topology diagram of the multi-renewable energy feeding system after the grid-connected energy storage is connected to the source-grid side.

[0028] Figure 4 The figure is a calculation flow chart of the grid-type energy storage capacity configuration method. DETAILED DESCRIPTION

[0029] Reference will now be made in detail to exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.

[0030] Example 1

[0031] First, for the grid structure with multiple renewable energy feed-in, the multiple renewable energy stations short-circuit ratio (MRSCR) is used to evaluate the voltage support level of the renewable energy stations in the initial state. The specific calculation method is as follows:

[0032] Consider Figure 1 In the grid topology of the multi-renewable energy feed-in system shown in the figure, different renewable energy stations are connected from the low-voltage side nodes and connected to the high-voltage side busbar through the boost line. The high-voltage side busbar nodes are connected to each other through the line and are respectively connected through the impedance Z i0 The high voltage side busbar is connected to the equivalent impedance Z GFor the grid-connected system of the new energy station, the AC system connected to the new energy is simplified into an ideal voltage source and an equivalent impedance in series with it through the multi-port Thevenin equivalent method, and the new energy station is equivalent to a current source. For the low-voltage side nodes and the high-voltage side nodes, they can be converted into the form of Figure 2 The equivalent node model is shown, and the new energy multi-station short-circuit ratio MRSCR of the new energy grid-connected node on the low-voltage side or high-voltage side is obtained respectively.

[0033] like Figure 2 In the equivalent node model shown, Z ij is the equivalent impedance between nodes i and j, Z i Equivalent power supply for the main network i The system side equivalent impedance between the corresponding grid-connected points. Assume that the current injected into the AC system by the grid-connected busbars of nodes 1, 2, ..., n is According to the node voltage equation, the voltages of nodes 1, 2, ..., n are

[0034]

[0035] In the formula, Z EQij is the node impedance matrix Z of the multi-port Thevenin equivalent model EQ The i-th row and j-th column element of ; i, j∈{1,2,…,n}.

[0036] Further based on the concept of short-circuit ratio of new energy multiple stations, the short-circuit ratio MRSCR of new energy multiple stations at node i can be calculated: i :

[0037]

[0038] Where: S ACi 、E i , U Ni , U i ,I i They represent the short-circuit capacity, AC system equivalent potential, nominal voltage, voltage amplitude, and current amplitude of node i respectively. j is the voltage amplitude at node j, S EQi represents the equivalent grid-connected capacity of node i considering the mutual influence between the feed-in branches of other renewable energy stations, S REi represents the new energy capacity injected into node i, S REi represents the new energy capacity injected into node i, Z EQii , Z EQij Represent the system equivalent node impedance matrix Z EQ The self-impedance and mutual impedance of the corresponding nodes.

[0039] Furthermore, according to formula (2), the increase in the grid-connected capacity of new energy will reduce its MRSCR. The smaller the MRSCR, the weaker the grid strength, and the worse the voltage stability of the new energy station under grid disturbance. For the short-circuit ratio of new energy multi-stations at the node, the indicators shown in Table 1 can be used to evaluate the initial stability interval of the new energy station:

[0040] Table 1 Stable range of new energy stations

[0041]

[0042] When MRSCR is greater than 2.0, it is generally believed that the new energy station has a strong access to the system and the system voltage stability is good. When MRSCR is less than 2.0, the short-circuit ratio of the new energy station can be adjusted by configuring a grid-type energy storage. The impact of the grid-type energy storage configuration on the short-circuit ratio of multiple new energy stations is mainly manifested in two aspects: providing short-circuit capacity to the power grid system and changing the equivalent impedance matrix of the system.

[0043] like Figure 1 Under the topological structure shown in the figure, the configuration of grid-type energy storage can be divided into source-side grid-type energy storage and grid-side grid-type energy storage. The topology after configuration is as follows: Figure 3 As shown. The source-side grid-type energy storage is connected in parallel with the i-th renewable energy source to the low-voltage bus node at the renewable energy station, while the grid-type energy storage on the grid side is independently connected to the high-voltage side renewable energy station collection bus of the system via the boost line. After configuring the source-side grid-type energy storage and the grid-type energy storage on the grid side at different nodes, Figure 3 compared to Figure 1 The node impedance matrix of the entire network will change. At the same time, the access of grid-connected energy storage will provide more short-circuit capacity for the system, thereby improving the MRSCR of each new energy station.

[0044] The MRSCR calculation method after grid-connected energy storage is as follows:

[0045] Due to the voltage source characteristics of the grid-type energy storage, after configuring the grid-type energy storage at different nodes, the source-side grid-type energy storage can be equivalent to a voltage source with equivalent impedance Z si , the equivalent potential is E si The voltage source, the grid-type energy storage Thevenin equivalent circuit on the grid side is with equivalent impedance Z P , the equivalent potential is E P voltage source. Figure 2 Under the grid topology shown in FIG, that is, before configuring the grid-connected energy storage, the node voltage equation at the low-voltage side busbar new energy access node can be obtained after multi-port Thevenin equivalent as shown in formula (1), and Figure 3After the source-side grid-type energy storage and the grid-side grid-type energy storage are connected to different nodes, the multi-port equivalent Thevenin circuit will change, which will further change the equivalent node impedance matrix. Among them, the grid-side grid-type energy storage configuration mainly affects the equivalent system equivalent potential E i With the equivalent impedance, from the low-voltage side node, the equivalent potential E of the AC side before the grid-type energy storage is connected i Equivalent to the system equivalent power supply E, the equivalent impedance Z of node i i As shown in formula (3), after the grid-type energy storage is connected to the grid side, the changes of the system multi-port Thevenin equivalent circuit are shown in formulas (4) and (5).

[0046]

[0047]

[0048] in and are the equivalent potential and equivalent impedance of the multi-port Thevenin equivalent circuit of the system after the grid-type energy storage is connected to the grid. Comparing equations (3) and (5), after the grid-type energy storage is connected to the grid, the equivalent impedance expression adds a term Z P / (Z G +Z P ), making its value decrease, further making each element Z in the node impedance matrix EQij Decrease, where Z i0 , i∈{1,2,…,n} is the impedance value from the high-voltage side bus node to the high-voltage side collection bus node corresponding to the new energy site i, E P is the grid-side grid-type energy storage equivalent potential, Z P is the equivalent impedance of the grid-type energy storage to the system, Z G is the equivalent impedance of the AC grid.

[0049] For the source-side grid-connected energy storage access, it is equivalent to adding a ground impedance Z at node i. si , resulting in changes in the node impedance matrix. For example, when only the grid-connected energy storage is connected to node 1, the node impedance matrix changes as follows:

[0050]

[0051] Among them, Z' EQ is the node impedance matrix of the renewable energy multi-feed system after the source-side grid-type energy storage is connected, Z EQ1 is the initial node impedance matrix Z EQ The first row, Z EQ1 T Z EQ1 The transposed matrix of Z s1 is the equivalent impedance of the grid-type energy storage connected to the source side of node 1.EQ ', the following changes will occur for each element:

[0052]

[0053] Among them, Z' EQij The node impedance matrix Z' after the source-side grid-type energy storage is connected EQ The i-th row and j-th column element of Z; i, j∈{1,2,…,n}. EQij is the initial node impedance matrix Z EQ The i-th row and j-th column element of Z EQ1i With Z EQ1j Z EQ The element in the 1st row, i-th column, j-th column.

[0054] It can be seen from formula (7) that due to the access of a node grid-type energy storage, each element in the node impedance matrix is ​​reduced, and the diagonal element at the corresponding node will be reduced more than other elements. If each node is equipped with source-side grid-type energy storage, the main diagonal elements in the node impedance matrix will be significantly reduced. According to formula (2), the main diagonal element Z EQii The reduction will increase the system short-circuit capacity and improve the short-circuit ratio of new energy.

[0055] The access of grid-connected energy storage on the source-grid side will also provide additional short-circuit current for the new energy system, thereby further increasing the short-circuit capacity and improving the short-circuit ratio of multiple new energy stations. Assume that the node impedance matrix of the new energy multi-feed system after the access of grid-connected energy storage is The diagonal elements in the matrix are For the grid-side grid-type energy storage, due to its voltage source nature, the additional short-circuit current I provided to node i after connection SCPi for:

[0056]

[0057] For the source-side grid-type energy storage, due to its voltage source characteristics, the additional short-circuit current I provided to node i after configuration is SCSi for:

[0058]

[0059] Among them, E Si is the equivalent potential of the source-side grid-type energy storage to node i, Z si is the equivalent impedance of the source-side grid-type energy storage to node i.

[0060] Therefore, when the source-side grid-connected energy storage and the grid-side grid-connected energy storage are configured together, the short-circuit capacity provided by the AC system and the grid-connected energy storage to the grid connection point will become

[0061]

[0062] in, The node impedance matrix of the new energy multi-feed system after the grid-type energy storage is connected to the source-grid side The i-th row and i-th column elements (diagonal elements) in .

[0063] Furthermore, the short-circuit ratio of the new energy station at node i after the grid-connected energy storage is becomes:

[0064]

[0065] Where S Mi With S Mj is the source-side grid-connected energy storage capacity at nodes i and j, The node impedance matrix of the new energy multi-feed system after the grid-type energy storage is connected to the source-grid side The i-th row and j-th column element in S REi With S REj is the capacity of the new energy connected at nodes i and j.

[0066] Compared with formula (2), when all new energy stations and network hub nodes are connected to the grid-type energy storage, the MRSCR of each node in the network will be improved. By reasonably configuring the capacity of the grid-type energy storage, the voltage support capacity of the entire network will be improved. According to formula (11), it can be seen that there is a certain corresponding relationship between the capacity of the grid-type energy storage and the MRSCR. At the same time, considering the current overload capacity of the grid-type energy storage converter, under the condition of limited overload current, the actual short-circuit current provided by the grid-type energy storage part will also be limited. Based on the three times overcurrent capacity currently specified for the grid-type energy storage converter, the actual short-circuit current that the source-grid side grid-type energy storage can provide should be:

[0067]

[0068] Where S MP For the grid-side grid-type energy storage capacity, when calculating the short-circuit ratio of multiple new energy stations, the short-circuit capacity is also determined by the grid-type energy storage capacity itself:

[0069]

[0070] Among them, f MRSCRi (S Mi ,S MP ) is the short-circuit capacity at node i after the grid-connected energy storage is connected, and S is the source-side grid-connected energy storage capacity S at node i. Mi And the grid-side grid-type energy storage capacity S MP function.

[0071] According to the above functional relationship, the present invention takes the MRSCR of each node in the network as the optimization target, and the capacity of the grid-type energy storage connected to each node as the optimization independent variable, and uses the Pareto multi-objective optimization method. By setting the target MRSCR of each node, the grid-type energy storage configuration capacity of each new energy station and network hub node can be obtained.

[0072] The objective function of the grid-type energy storage configuration capacity optimization model is:

[0073]

[0074] MRSCR obj is the MRSCR target value. The MRSCR after grid-connected energy storage configuration should be greater than or equal to the original MRSCR. Therefore, the constraint condition is:

[0075] f MRSCRi (S Mi ,S MP )≥MRSCR obj (16)

[0076] Through the above analysis, it can be seen that the access of grid-type energy storage can indeed change the short-circuit ratio of new energy multi-stations at the response node. This application uses the corresponding relationship between the short-circuit ratio of new energy multi-stations and the station capacity, and takes the short-circuit ratio of new energy multi-stations as the target to configure the capacity of grid-type energy storage, thereby improving the voltage support capacity of the entire grid and new energy stations.

[0077] Reference Figure 4 A method for configuring grid-type energy storage capacity to improve the short-circuit ratio of new energy stations, firstly, determining the number of new energy stations and then determining the number of nodes, and at the same time determining the nominal voltage of each node, and determining the short-circuit ratio of new energy multiple stations of each new energy station in the initial situation according to the impedance parameters in the grid architecture and the capacity of the new energy station;

[0078] Secondly, the new energy multi-station short-circuit ratio of each new energy station is compared with the target new energy multi-station short-circuit ratio. If it is greater than the target new energy multi-station short-circuit ratio, there is no need to configure a grid-forming energy storage (GFMS) for this new energy station; if it is less than the target new energy multi-station short-circuit ratio, it is necessary to configure a source-side grid-forming energy storage at this new energy station, and use a multi-objective optimization algorithm to further determine the source-side and grid-side grid-forming energy storage capacities based on the node information that needs to be configured; ultimately, the new energy multi-station short-circuit ratio of each node reaches the target new energy multi-station short-circuit ratio.

[0079] In addition, the maximum short-circuit capacity provided by the grid-connected energy storage under overload current limiting conditions will not exceed the short-circuit capacity under non-current limiting conditions, so the constraint condition is:

[0080]

[0081] Through the multi-objective optimization function established by equations (15)-(17) and the corresponding constraints, the corresponding relationship between the short-circuit ratio of multiple renewable energy stations and the capacity of renewable energy stations is used to optimize the short-circuit ratio of each renewable energy station and configure the capacity of the grid-connected energy storage. The specific process is described in Figure 4 , thereby improving the voltage support capacity of the entire grid and new energy stations.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for configuring grid-type energy storage capacity to improve the short-circuit ratio of new energy stations, characterized in that: Determine the number of new energy stations and then the number of nodes, and at the same time determine the nominal voltage of each node, and determine the new energy multi-station short-circuit ratio of each new energy station in the initial situation according to the impedance parameters and the capacity of the new energy station in the power grid architecture; compare the new energy multi-station short-circuit ratio of each new energy station with the target new energy multi-station short-circuit ratio. If it is greater than the target new energy multi-station short-circuit ratio, then there is no need to configure grid-forming energy storage for this new energy station; if it is less than the target new energy multi-station short-circuit ratio, it is necessary to configure source-side grid-forming energy storage at this new energy station, and use a multi-objective optimization algorithm to further determine the source-side and grid-side grid-forming energy storage capacities based on the node information that needs to be configured; ultimately, the new energy multi-station short-circuit ratio of each node reaches the target new energy multi-station short-circuit ratio.

2. A method for configuring grid-type energy storage capacity for improving the short-circuit ratio of a new energy station according to claim 1, characterized in that: The short-circuit ratio of the new energy multi-station at node i before the grid-connected energy storage is calculated as follows: Where: S ACi 、E i , U Ni , U i ,I i They represent the short-circuit capacity, AC system equivalent potential, nominal voltage, voltage amplitude, and current amplitude of node i respectively. j is the voltage amplitude at node j, S EQi represents the equivalent grid-connected capacity of node i considering the mutual influence between the feed-in branches of other renewable energy stations, S REi represents the new energy capacity injected into node i, S REi represents the new energy capacity injected into node i, Z EQii , Z EQij Represents the system equivalent node impedance matrix Z EQ The self-impedance and mutual impedance of the corresponding nodes.

3. A method for configuring grid-type energy storage capacity for improving the short-circuit ratio of a new energy station according to claim 2, characterized in that: Short-circuit ratio of new energy station at node i after grid-connected energy storage becomes: Where S Mi With S Mj is the source-side grid-connected energy storage capacity at nodes i and j, The node impedance matrix of the new energy multi-feed system after the grid-type energy storage is connected to the source-grid side The i-th row and j-th column element in S REi With S REj is the capacity of the new energy connected to nodes i and j, The node impedance matrix of the new energy multi-feed system after the grid-type energy storage is connected to the source-grid side The i-th row and i-th column element in E P is the grid-side grid-type energy storage equivalent potential, E Si is the equivalent potential of the source-side grid-type energy storage to node i, Z si is the equivalent impedance of the source-side grid-type energy storage to node i; E is the equivalent power supply.

4. A method for configuring grid-type energy storage capacity for improving the short-circuit ratio of a new energy station according to claim 3, characterized in that: After the grid-connected energy storage is connected, the short-circuit capacity at node i is calculated as follows: Among them, f MRSCRi (S Mi ,S MP ) is the short-circuit capacity at node i after the grid-connected energy storage is connected, and S is the source-side grid-connected energy storage capacity S at node i. Mi And the grid-side grid-type energy storage capacity S MP The function of S MP It is the grid-type energy storage capacity for the grid side.

5. A method for configuring grid-type energy storage capacity for improving the short-circuit ratio of a new energy station according to claim 4, characterized in that: The short-circuit ratio of new energy multi-stations at each node is taken as the optimization target, and the capacity of the grid-connected energy storage connected to each node is taken as the optimization independent variable. The objective function of the grid-connected energy storage configuration capacity optimization model is established, and the target short-circuit ratio of new energy multi-stations at each node is set. The Pareto multi-objective optimization method is used to obtain the grid-connected energy storage configuration capacity of each new energy station and network hub node.

6. A method for configuring grid-type energy storage capacity for improving the short-circuit ratio of a new energy station according to claim 5, characterized in that: The objective function of the grid-type energy storage configuration capacity optimization model is: MRSCR obj is the MRSCR target value. The short-circuit ratio of the new energy multi-station after the grid-type energy storage configuration should be greater than or equal to the original MRSCR. Therefore, the constraint condition is: f MRSCRi (S Mi ,S MP )≥MRSCR obj (16)。 7. A method for configuring grid-type energy storage capacity for improving the short-circuit ratio of a new energy station according to claim 6, characterized in that: The maximum short-circuit capacity provided by the grid-connected energy storage under overload current limiting conditions will not exceed the short-circuit capacity under non-current limiting conditions, so the constraint condition is: Through the multi-objective optimization function established by equations (15)-(17) and the corresponding constraints, the corresponding relationship between the short-circuit ratio of multiple renewable energy stations and the capacity of renewable energy stations is utilized to optimize the short-circuit ratio of each renewable energy station and configure the capacity of the grid-type energy storage.

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