A new energy multi-field station short circuit ratio calculation method, system and storage medium

Abstract

The application discloses a new energy multi-station short-circuit ratio calculation method and system, and a storage medium. The method comprises the following steps: performing network topology analysis on a power grid model I containing an external network model to obtain a total topology node set; forming a node admittance matrix according to the device resistance, the electric reactance parameter and the topology node set of the power grid model I, processing the node admittance matrix to obtain a factor table of the node admittance matrix; calculating self-impedance and mutual impedance of nodes corresponding to new energy stations in a node impedance matrix according to the factor table; obtaining short-circuit currents of each node when three-phase short-circuit faults occur, and calculating short-circuit capacities of each node; obtaining new energy multi-station short-circuit ratios of each node according to the short-circuit capacities, the self-impedance and the mutual impedance; and obtaining new energy multi-station short-circuit ratios according to the short-circuit ratios of each node. The application considers the influence of the external network model and the characteristics of a new energy voltage-controlled power supply on the calculation of new energy multi-station short-circuit ratios, and improves the accuracy of the calculation results.

Description

Technical Field

[0001] This invention relates to the field of power system technology, specifically to a method, system, and storage medium for calculating the short-circuit ratio of multiple new energy power plants. Background Technology

[0002] As the proportion of new energy sources, such as wind and solar power, in my country's power grid continues to increase, their impact on the safe operation of the existing power grid is becoming increasingly apparent. In some areas, new energy sources have been integrated into weak AC power grids. The national mandatory standard GB38755-2019 "Guidelines for the Safety and Stability of Power Systems" clearly requires that the short-circuit ratio of new energy power plants should reach a reasonable level.

[0003] When calculating the short-circuit ratio of large-scale wind power and photovoltaic power plants, the significant differences between wind turbines and photovoltaic generators and synchronous generators in terms of generator mechanism, grid topology, and control methods mean that the circuit model of voltage source and reactance in series cannot be used. This makes traditional short-circuit ratio calculation programs unsuitable for solving the short-circuit ratio calculation of multiple renewable energy power plants, seriously affecting the accuracy of the short-circuit ratio calculation results and thus significantly impacting the accurate quantitative assessment of the scale of renewable energy access.

[0004] A preliminary search of existing patents related to short-circuit ratio methods for renewable energy power plants reveals the following: Chinese patent CN112531765A, "A Method and Device for Determining the Short-Circuit Ratio of a Renewable Energy Power Plant," relates to the field of renewable energy technology. It determines the short-circuit ratio of a renewable energy power plant based on the short-circuit capacity of the grid connection point, but does not explain how the short-circuit capacity of the grid connection point is accurately calculated. Chinese patent CN107276110A, "A Method and System for Calculating the Short-Circuit Ratio of a Renewable Energy Power Plant," relates to the field of power system technology. It calculates the short-circuit ratio of a renewable energy power plant by establishing an equivalent node impedance matrix and considering the active power of renewable energy units. Chinese patent CN109004690A, "A Panoramic Evaluation Method, System, Storage Medium, and Computing Equipment for the Short-Circuit Ratio of Multiple Renewable Energy Power Plants," calculates the short-circuit ratio of multiple power plants based on a set of strongly correlated renewable energy units at each node. Chinese patent CN202110314710, "An Evaluation Method for the Carrying Capacity of a Distribution Network," belongs to the field of distribution network carrying capacity evaluation, primarily assessing the ability of a distribution network to support distributed renewable energy. Analysis revealed that none of these methods provided explanations for calculating the short-circuit ratio of multiple power plants in power dispatch automation systems, taking into account the impact of external grids, reactive power output from new energy sources, and voltage control characteristics of new energy power sources.

[0005] Therefore, existing technologies suffer from low accuracy in calculating the short-circuit ratio of multiple new energy power plants because they do not consider the influence of the external grid. Summary of the Invention

[0006] The purpose of this invention is to provide a method, system, and storage medium for calculating the short-circuit ratio of multiple new energy power plants, so as to solve the problem that the calculation accuracy of the short-circuit ratio of multiple new energy power plants does not take into account the influence of the external network in the prior art.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0008] In a first aspect, this invention discloses a method for calculating the short-circuit ratio of multiple new energy power stations, including:

[0009] The obtained upper-level power grid model and cross-section are spliced ​​together with the obtained local power grid model and cross-section to obtain power grid model one containing the external grid model;

[0010] A network topology analysis is performed on the power grid model 1 to obtain the total topology node set BS. All Wherein, the total topology node set BS All Includes the set of topological nodes for new energy power stations (BS) re ;

[0011] Based on the equipment resistance, reactance parameters, and total topology set BS of power grid model 1 All Form the node admittance matrix of power grid model one, and process the node admittance matrix to obtain the factor table of the node admittance matrix;

[0012] The set of topological nodes BS of the new energy power station in the node impedance matrix is ​​calculated based on the factor table of the node admittance matrix. re The self-impedance and mutual impedance of the corresponding nodes;

[0013] Obtain the set of topological nodes of the new energy power station BS re The short-circuit current of each node is calculated, and the short-circuit capacity of each node is obtained.

[0014] Based on the short-circuit capacity of each node and BS re The short-circuit ratio of each node is obtained by measuring its self-impedance and mutual impedance.

[0015] The short-circuit ratio of multiple new energy power stations is obtained based on the short-circuit ratio of each node.

[0016] Furthermore, in obtaining the new energy power station topology node set BS re The short-circuit current at each node also includes:

[0017] Dynamically partition the power grid model to form a main power grid partition and N sub-power grid partitions;

[0018] For power grids containing renewable energy power plants, power flow calculations are performed based on the actual output of all generators and loads, including those generating renewable energy, to obtain the voltage of all nodes under normal operating conditions.

[0019] A power flow-based short-circuit current calculation method is used to obtain the topology node set BS of the new energy power station. re When a three-phase short-circuit fault occurs at node f, the voltage of all nodes in the power grid

[0020] Furthermore, obtain the set of topological nodes BS for new energy power stations. re When a three-phase short-circuit fault occurs at node f, the voltage of all nodes in the power grid include:

[0021] When a three-phase short-circuit fault occurs at node f, and the voltage of the root node in the s-th sub-region of the power grid is less than the critical voltage, the output current of the new energy power source is obtained based on the voltage control characteristics of the new energy power source. When there is no new energy power source in the s-th sub-region of the power grid or the voltage of the root node is greater than the critical voltage, there is no need to modify the output current of the new energy power source in sub-region s. When the absolute value of the difference between the (k+1)-th voltage correction amount and the k-th voltage correction amount at node f is less than or equal to the set value, the output current correction amount of the new energy power source is obtained.

[0022] Based on the voltage control characteristics of new energy power sources, and based on the voltage of all nodes in the power grid when a three-phase short-circuit fault occurs at node f. The output current correction of the new energy power source is calculated iteratively under the drop condition, and the voltage correction of all nodes in the power grid is solved.

[0023] When the absolute value of the difference between the (k+1)th voltage correction and the kth voltage correction at node is less than a set value, the voltages of all nodes in the power grid when a three-phase short circuit occurs at node f are obtained.

[0024] Furthermore, the dynamic partitioning of the power grid model one includes:

[0025] The power grid model 1 is decomposed using the node splitting method;

[0026] Based on the operation mode of power grid model one, dynamic partitioning is performed, dividing the power grid above 220kV / 330kV into the main power grid partition, and dividing the power grid below 220kV / 330kV into N sub-power grid partitions.

[0027] Furthermore, the formula for calculating the short-circuit ratio of the new energy multi-station is as follows:

[0028]

[0029] Where: i is the topology node number of the new energy power station, S aci S represents the short-circuit capacity of the i-th renewable energy power station topology node; req,iZ represents the equivalent power of the i-th renewable energy power station after considering the influence of other renewable energy power stations; ii Let Z be the element in the i-th row and i-th column of the nodal impedance matrix Z; ij S is the element in the i-th row and j-th column of the nodal impedance matrix Z; rei For the i-th renewable energy power station connected to the grid, S rej The power output of the j-th renewable energy power station connected to the grid is shown as [value].

[0030] Further, processing the node admittance matrix to obtain the factor table of the node admittance matrix includes:

[0031] The node numbers in the node admittance matrix are reordered using an approximate minimum degree sorting method, and the factor table of the node admittance matrix is ​​calculated.

[0032] Secondly, this invention discloses a short-circuit ratio calculation system for multiple new energy power stations, characterized in that it includes:

[0033] The splicing module is used to splice the acquired upper-level power grid model and cross-section with the acquired local power grid model and cross-section to obtain a power grid model one containing the external grid model;

[0034] The topology analysis module is used to perform network topology analysis on the power grid model 1 to obtain the total topology node set BS. All Wherein, the total topology node set BS All Includes the set of topological nodes for new energy power stations (BS) re ;

[0035] The factor table generation module is used to generate the factor table based on the equipment resistance, reactance parameters, and total topology node set BS of the power grid model 1. All Form the node admittance matrix of power grid model one, and process the node admittance matrix to obtain the factor table of the node admittance matrix;

[0036] The impedance calculation module is used to calculate the set of topological nodes BS of the new energy power station in the node impedance matrix based on the factor table of the node admittance matrix. re The self-impedance and mutual impedance of the corresponding nodes;

[0037] The short-circuit capacity calculation module is used to obtain the set of topology nodes BS of the new energy power station. re The short-circuit current of each node is calculated, and the short-circuit capacity of each node is obtained.

[0038] The short-circuit ratio calculation module is used to calculate the short-circuit ratio based on the short-circuit capacity of each node and the BS. re The self-impedance and mutual impedance of the nodes are used to obtain the short-circuit ratio of each node; and the short-circuit ratio of the new energy multi-site is obtained based on the short-circuit ratio of each node.

[0039] Furthermore, in obtaining the new energy power station topology node set BS re The short-circuit current at each node also includes:

[0040] Dynamically partition the power grid model to form a main power grid partition and N sub-power grid partitions;

[0041] For power grids containing renewable energy power plants, power flow calculations are performed based on the actual output of all generators and loads, including those generating renewable energy, to obtain the voltage of all nodes under normal operating conditions.

[0042] A power flow-based short-circuit current calculation method is used to obtain the topology node set BS of the new energy power station. re When a three-phase short-circuit fault occurs at node f, the voltage of all nodes in the power grid

[0043] Furthermore, obtain the set of topological nodes BS for new energy power stations. re When a three-phase short-circuit fault occurs at node f, the voltage of all nodes in the power grid include:

[0044] When a three-phase short-circuit fault occurs at node f, and the voltage of the root node in the s-th sub-region of the power grid is less than the critical voltage, the output current of the new energy power source is obtained based on the voltage control characteristics of the new energy power source. When there is no new energy power source in the s-th sub-region of the power grid or the voltage of the root node is greater than the critical voltage, there is no need to modify the output current of the new energy power source in sub-region s. When the absolute value of the difference between the (k+1)-th voltage correction amount and the k-th voltage correction amount at node f is less than or equal to the set value, the output current correction amount of the new energy power source is obtained.

[0045] Based on the voltage control characteristics of new energy power sources, and based on the voltage of all nodes in the power grid when a three-phase short-circuit fault occurs at node f. The output current correction of the new energy power source is calculated iteratively under the drop condition, and the voltage correction of all nodes in the power grid is solved.

[0046] When the absolute value of the difference between the (k+1)th voltage correction and the kth voltage correction at node is less than a set value, the voltages of all nodes in the power grid when a three-phase short circuit occurs at node f are obtained.

[0047] Thirdly, the present invention discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0048] Fourthly, the present invention discloses an electronic device, including a processor and a storage medium;

[0049] The storage medium is used to store instructions;

[0050] The processor is configured to operate according to the instructions to perform the steps of any of the methods described above.

[0051] According to the above technical solution, the embodiments of the present invention have at least the following effects:

[0052] This application splices the upper-level power grid model and cross-section with the local power grid model and cross-section to obtain the power grid model for subsequent analysis. It takes into account the impact of the external grid model on the calculation of the short-circuit ratio of multiple new energy power plants, thereby improving the accuracy of the calculation results of the short-circuit ratio of multiple new energy power plants. Attached Figure Description

[0053] Figure 1 This is a flowchart of the calculation method of the present invention. Detailed Implementation

[0054] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0055] The short-circuit ratio calculation method of this application obtains and splices together the upper-level and local-level dispatch grid models and cross-sections. Based on the spliced ​​model containing the external grid, topology analysis is performed to form a node branch model. A node splitting method is used for dynamic hierarchical partitioning and minimum-degree node reordering to form an admittance matrix factor table. The initial voltage of the grid nodes under short-circuit conditions is calculated using a power flow-based method. Based on the characteristics of the renewable energy voltage-controlled power supply, the output current of the renewable energy power supply is corrected. The node voltages at the renewable energy grid connection point under three-phase short circuits are iteratively solved to obtain the three-phase short-circuit capacity considering the voltage control characteristics of the renewable energy power supply. A continuous back-substitution method using multi-threaded parallel technology is employed to calculate the self-impedance and mutual impedance of the renewable energy power supply grid connection point nodes, thereby quickly obtaining the short-circuit ratio of multiple renewable energy power plants. This invention considers the control characteristics of renewable energy power supplies, and the calculated short-circuit ratio of the renewable energy power plant grid connection nodes has higher accuracy, better meeting the requirements of engineering applications.

[0056] Example 1

[0057] This embodiment discloses a method for calculating the short-circuit ratio of multiple power stations in a new energy source. The method includes splicing together the acquired upper-level power grid model and cross-section with the acquired local-level power grid model and cross-section to obtain a power grid model one containing the external grid model; and performing network topology analysis on the power grid model one to obtain the total topology node set BS. All Among them, the total set of power grid topology nodes BS All Includes the set of topological nodes for new energy power stations (BS) re Based on the equipment resistance, reactance parameters, and total topology node set BS of power grid model one. AllThe node admittance matrix of power grid model one is formed, and the factor table of the node admittance matrix is ​​obtained by processing the node admittance matrix; based on the factor table of the node admittance matrix, the set of new energy power station topology nodes BS in the node impedance matrix is ​​calculated. re The self-impedance and mutual impedance of the corresponding nodes are obtained; the set of topological nodes BS of the new energy power station is obtained. re The short-circuit current of each node is calculated, and the short-circuit capacity of each node is obtained; based on the short-circuit capacity of each node and BS re The short-circuit ratio of each node is obtained by measuring its self-impedance and mutual impedance; based on the short-circuit ratio of each node, the short-circuit ratio of the new energy multi-site is obtained.

[0058] This application splices the upper-level power grid model and cross-section with the local power grid model and cross-section to obtain the power grid model for subsequent analysis. It takes into account the impact of the external grid model on the calculation of the short-circuit ratio of multiple new energy power plants, thereby improving the accuracy of the calculation results of the short-circuit ratio of multiple new energy power plants.

[0059] Specifically, such as Figure 1 As shown, a method for calculating the short-circuit ratio of multiple new energy power plants includes the following steps:

[0060] Step 1: Obtain the models and real-time measurements of the power grid under the jurisdiction of the upper-level and local dispatching systems respectively by adopting standardized model section services. Then, stitch together the power grid model obtained from the upper-level dispatching system and the power grid model containing new energy power plants modeled in the local dispatching system to obtain a power grid model 1 containing the external network model as the power grid model for calculating the short-circuit ratio of multiple new energy power plants.

[0061] In this step, the service enables the wide-area acquisition of power grid models and measurement sections across multiple levels of dispatch centers and dispatch systems. At the same time, the standardized model and measurement section services can be provided by different software vendors, without the requirement that the model and measurement section services and the new energy short-circuit calculation software must be from the same software vendor.

[0062] By splicing together the grid models and cross-sectional data of the upper-level and local control systems, the calculation model was expanded. The impact of the external grid model on the short-circuit ratio calculation of multiple new energy power plants at the local level was considered, which improved the accuracy of the short-circuit ratio calculation results.

[0063] Step 2: Based on the connection relationships and remote signaling switching status of the power grid equipment components in the spliced ​​power grid model 1, perform network topology analysis to obtain the set of all topology nodes as BS. All The set of topological nodes at the grid connection point of the new energy power station (the high-voltage side bus node of the new energy power station booster station) is denoted as BS. re Let the topology node number of the i-th renewable energy power station grid connection point be i, i∈BS re At the same time, i∈BS AllThis forms the electrical island-node-branch model of the power grid.

[0064] Since renewable energy power plants typically connect to lower voltage grids, and because individual generating units within these plants are relatively small in capacity but numerous, and different renewable energy power plants connect to the grid through the same node, a topology node set BS is formed at the grid connection point of the renewable energy power plant. re When calculating the short-circuit ratio of multiple new energy power stations, it is not necessary to calculate the short-circuit ratio of a single generator within the new energy power station. Instead, the short-circuit ratio of the grid connection point of the new energy power station (the high-voltage side bus node of the new energy power station booster station) is calculated.

[0065] Step 3: Dynamically partition the power grid model 1 using the node splitting method. The topology search method adopts a breadth-first search method based on a linked list structure, forming a main power grid partition and N sub-power grid partitions, where the root node of the s-th electrical partition is node s. root The set of all electrical nodes under this partition is BS. S , there is s root ∈BS S BS S ∈BS All .

[0066] In this step, the power grid is decomposed at the high-voltage side nodes of 220kV / 330kV substations using a node splitting method. Dynamic partitioning is performed based on real-time grid operation. Grids at voltage levels above 220kV / 330kV form the main grid partition, while networks below 220kV / 330kV form N sub-partitions. This ensures that all resulting grid partitions are internally interconnected, and that sub-partitions are decoupled and independent, connected only through the main partition network.

[0067] Step 4: Based on the equipment resistance, reactance parameters and topology nodes of the power grid, form the node admittance matrix Y of the power grid, and use the minimum degree node sorting method to reorder and calculate the factor table LDU of the node admittance matrix.

[0068] In this step, since new energy power stations are usually connected to lower voltage level power grids, when the coverage area of ​​new energy power stations is large, the equivalent resistance and equivalent reactance of each power station's grid connection point vary greatly depending on the voltage level of the connection point. When forming the node admittance matrix Y of the power grid based on the equipment resistance, reactance parameters and topology nodes of the power grid, the resistance and reactance of the equipment need to be considered at the same time.

[0069] The node admittance matrix is ​​stored in a sparse format based on associative containers, which avoids the need for additional matrix memory allocation and initialization work before computation, as required by traditional array-based methods. It also avoids designing complex data structures such as two-dimensional linked lists or cross-linked lists to implement matrix traversal and insertion operations. It makes full use of the efficient algorithms provided by the standard template library to minimize unnecessary memory allocation and matrix access operations.

[0070] Since the node numbering order directly affects the sparsity of the node admittance matrix factor table, which has a direct impact on computational efficiency, this invention uses an approximate minimum degree sorting method to reorder the node numbers based on the non-zero element structure of the node admittance matrix in order to reduce the number of injected elements in the factorization process. The reordered node admittance matrix is ​​then subjected to LDU factorization using Gaussian elimination to form the factor table.

[0071] In this step, the set of topological nodes BS of the new energy power station in the node impedance matrix is ​​calculated based on the factor table of the node admittance matrix. re The self-impedance and mutual impedance of the corresponding nodes are used to calculate the subsequent short-circuit capacity.

[0072] Step 5: For power grids containing renewable energy power plants, perform power flow calculations based on the actual output of all generators and loads including renewable energy power generation, and calculate the node voltage values ​​under normal operating conditions. Among them, the injection current of the new energy power source is the real-time current.

[0073] Based on the spliced ​​grid model cross section, the injection current of the new energy power source is used for power flow calculation in real time. The node admittance matrix and node voltage value under the actual operation mode are calculated, and the short-circuit current can be calculated more accurately, avoiding the problem of the short-circuit current being too large when using the full start-up and full connection mode.

[0074] Step 6: Let node f be the set of topological nodes BS of the grid connection point of the new energy power station. re For a node in BS, f∈BS re The voltage of all nodes in the power grid under the condition of a three-phase short circuit occurs at node f of a new energy power station, using a power flow-based short-circuit current calculation method. (Let the iteration number k = 1 at this point, that is:) When calculating, the open-circuit voltage at the fault point is taken as the node voltage obtained from the power flow calculation in the previous step. The injection current of the new energy node is taken as the actual output current of the new energy power source.

[0075] A power flow-based short-circuit current calculation method is adopted to obtain the voltage of all nodes in the power grid when a three-phase short circuit occurs at node f of a new energy power station. This method can accurately reflect the short-circuit current under the current real-time power flow mode of the power grid. At the same time, it takes into account the influence of new energy power sources on the short-circuit current, avoiding the problem of large discrepancies between the short-circuit current and the real-time power grid in the classical short-circuit current method based on the scheme (generator internal electromotive force E″=1.0∠0°).

[0076] Step 7, set U thld The set critical voltage value (usually taken as 0.9) is the voltage of the root node in the s-th sub-region of the power grid when a three-phase short-circuit fault occurs at node f. At that time, based on the type of renewable energy source, the output current of all renewable energy sources in sub-region s of the power grid under fault conditions is calculated. When there are no new energy sources or the root node voltage of the power grid sub-segment s At this time, there is no need to modify the output current of the generator nodes in sub-region s of the power grid. The correction amount for calculating the output current of the new energy power source is then...

[0077] As the proportion of renewable energy generation increases, the characteristics of the power grid change. When calculating short-circuit current, it is necessary to consider the output characteristics of the voltage-controlled current source of renewable energy. In practical engineering calculations, there is a simple and clear mapping relationship between the output current and voltage of renewable energy units. The output current of renewable energy units will only change when the grid connection point voltage is less than the critical voltage value (generally taken as 0.9). Since adjacent renewable energy power stations generally belong to the same electrical sub-zone, the output current of all renewable energy power sources in the grid sub-zone s under fault conditions can be obtained by directly judging the voltage of the root node of the sub-zone where the renewable energy power station is located. This avoids the problem of excessive time consumption caused by considering the global renewable energy units in the iterative calculation.

[0078] Step 8: Through equations Calculate the correction amount for solving the node voltage. Therefore, the node voltage vector when a three-phase short circuit occurs at node f in the (k+1)th time is obtained as follows:

[0079] Step 9: When the voltage correction values ​​obtained from the (k+1)th and kth calculations satisfy... Stop the iterative calculation if the time is right. Otherwise, proceed to step (7) for iterative calculation.

[0080] Step 10: Based on the iterative calculations in steps (7) to (9), obtain the voltages of all nodes when a three-phase short circuit occurs at node f, considering the characteristics of the new energy unit.

[0081] Since the short-circuit calculation model of new energy power generation differs significantly from that of conventional synchronous motor models, traditional short-circuit calculation methods are difficult to consider the voltage-controlled current source model of new energy power generation. Through iterative calculations in steps (7) to (9), the voltages of all nodes when a three-phase short circuit occurs at node f, considering the characteristics of the new energy unit, can be obtained. At this point, the voltage-controlled current source characteristics of the new energy unit output are considered, and the node voltage under fault conditions is calculated. More accurate.

[0082] Step 11: Calculate the short-circuit current at node f of the new energy power station under three-phase short-circuit conditions based on the subtransient reactance of the traditional generator and the control characteristics of the new energy generator. according to The short-circuit capacity of the grid-connected nodes of the new energy power station was calculated.

[0083] At this point, the calculation of the short-circuit current under the condition of a short circuit at node f of the new energy power station takes into account the control characteristics of new energy generation, thus the short-circuit capacity of the grid-connected node of the new energy power station is more accurate and can better meet the requirements of engineering applications.

[0084] Step 12: Calculate the short-circuit ratio (MRSCR) of multiple renewable energy power plants based on the node admittance matrix factor table, and calculate the MRSCR of the i-th renewable energy power plant. i The formula is as follows.

[0085]

[0086] Where: i is the grid connection node number of the new energy power station, S aci S represents the short-circuit capacity of the i-th renewable energy power station grid connection node; req,i Z represents the equivalent power of the i-th renewable energy power station after considering the influence of other renewable energy power stations; ii Let Z be the element in the i-th row and i-th column of the nodal impedance matrix Z; ij S is the element in the i-th row and j-th column of the nodal impedance matrix Z; rei For the i-th renewable energy power station connected to the grid, S rej The power output of the j-th renewable energy power station connected to the grid is shown as [value].

[0087] To improve the calculation speed of the short-circuit ratio of multiple renewable energy power plants under large-scale power grids, when calculating the elements in the node impedance matrix Z, it is only necessary to calculate the set of renewable energy power plant grid-connected topology nodes BS in Z. re The Bank of China uses the continuous back-substitution method based on the LDU factor table to solve for the elements of a certain row of the nodal impedance matrix Z. Meanwhile, when the set BS... reWhen the number of nodes in the topology is large, since the solutions for each row / column of the node impedance matrix are independent, multi-threaded parallel computing technology based on the factor table LDU is used to realize the parallel calculation of multiple rows of elements in the node impedance matrix Z, so as to improve the efficiency of Z. ii Z ij The calculation speed.

[0088] BS for the set of grid-connected nodes of new energy power plants re All nodes in the system use MRSCR i The calculation formula is used to calculate the short-circuit ratio of all new energy multi-stations.

[0089] In actual operation, renewable energy power plants provide reactive power to compensate for some reactive power losses in the power plant's collector lines and external transmission lines. This patent uses the apparent power of renewable energy generation to participate in the calculation of the short-circuit ratio of multiple renewable energy power plants, and also employs MRSCR. i The calculation formula takes into account the impedance difference between the grid-side access point and the grid connection point of the new energy power generation equipment, which can more accurately calculate the short-circuit ratio of multiple new energy power plants.

[0090] Example 2

[0091] Based on the same inventive concept as Embodiment 1, this embodiment also provides a new energy multi-station short-circuit ratio calculation system, which includes the following parts.

[0092] The splicing module is used to splice the acquired upper-level power grid model and cross-section with the acquired local power grid model and cross-section to obtain a power grid model one containing the external grid model;

[0093] The analysis module is used to perform network topology analysis on the power grid model 1 to obtain the total topology node set BS. All Wherein, the total topology node set BS All Includes the set of topological nodes for new energy power stations (BS) re ;

[0094] The factor table generation module is used to generate the factor table based on the equipment resistance, reactance parameters, and total topology node set BS of the power grid model 1. All Form the node admittance matrix of power grid model one, and process the node admittance matrix to obtain the node admittance matrix factor table;

[0095] The calculation module is used to obtain the set of topological nodes BS of the new energy power station. re The short-circuit current of each node is calculated, and the short-circuit capacity of each node is obtained.

[0096] The short-circuit ratio calculation module is used to calculate the short-circuit ratio based on the short-circuit capacity of each node and the BS. reThe self-impedance and mutual impedance of the nodes are used to obtain the short-circuit ratio of each node; and the short-circuit ratio of the new energy multi-site is obtained based on the short-circuit ratio of each node.

[0097] Furthermore, in obtaining the new energy power station topology node set BS re The short-circuit current at each node also includes:

[0098] Dynamically partition the power grid model to form a main power grid partition and N sub-power grid partitions;

[0099] Power flow calculations are performed on sub-regions of the power grid containing renewable energy power plants to obtain the voltage of all nodes under normal operating conditions.

[0100] A power flow-based short-circuit current calculation method is used to obtain the topology node set BS of the new energy power station. re When a three-phase short-circuit fault occurs at node f, the node voltage is... Wherein, the open-circuit voltage of node f is the voltage of node f under normal operating conditions.

[0101] Furthermore, obtain the set of topological nodes BS for new energy power stations. re When a three-phase short-circuit fault occurs at node f, the node voltage is... include:

[0102] When a three-phase short-circuit fault occurs at node f, and the voltage of the root node in the s-th sub-region of the power grid is less than the critical voltage, the output current of the new energy power source is obtained based on the voltage control characteristics of the new energy power source. When there is no new energy power source in the s-th sub-region of the power grid or the voltage of the root node is greater than the critical voltage, there is no need to modify the output current of the new energy power source in sub-region s. When the absolute value of the difference between the (k+1)-th voltage correction amount and the k-th voltage correction amount at node f is less than or equal to the set value, the output current correction amount of the new energy power source is obtained.

[0103] Based on the voltage control characteristics of the new energy power source, the output current correction of the new energy power source is calculated iteratively, and the voltage correction at node f is solved.

[0104] When the absolute value of the difference between the (k+1)th voltage correction and the kth voltage correction at node f is less than the set value, the node voltage at node f when a three-phase short circuit occurs is obtained.

[0105] Furthermore, the dynamic partitioning of the power grid model one includes:

[0106] The power grid model 1 is decomposed using the node splitting method;

[0107] Based on the operation mode of power grid model one, dynamic partitioning is performed, dividing the power grid above 220kV / 330kV into the main power grid partition, and dividing the power grid below 220kV / 330kV into N sub-power grid partitions.

[0108] Furthermore, the formula for calculating the short-circuit ratio of the new energy multi-station is as follows:

[0109]

[0110] Where: i is the topology node number of the new energy power station, S aci S represents the short-circuit capacity of the i-th renewable energy power station topology node; req,i Z represents the equivalent power of the i-th renewable energy power station after considering the influence of other renewable energy power stations; ii Let Z be the element in the i-th row and i-th column of the nodal impedance matrix Z; ij S is the element in the i-th row and j-th column of the nodal impedance matrix Z; rei For the i-th renewable energy power station connected to the grid, S rej The power output of the j-th renewable energy power station connected to the grid is shown as [value].

[0111] Further, processing the node admittance matrix to obtain the node admittance matrix factor table includes:

[0112] The node numbers in the node admittance matrix are reordered using an approximate minimum degree sorting method.

[0113] The reordered node admittance matrix is ​​subjected to LDU factorization using Gaussian elimination to obtain the node admittance matrix factor table.

[0114] Example 3

[0115] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0116] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0117] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0118] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0119] The embodiments of this application also provide an electronic device, which may be a tablet computer, a smartphone, a personal digital assistant, etc.

[0120] Electronic devices may include: memory, processor, communication interface and communication bus, the communication bus being used to enable communication between these components.

[0121] The memory is used to store all model data, as well as various data such as the calculation program instructions corresponding to the new energy multi-station short-circuit ratio calculation method and system provided in the embodiments of this application. The memory can be random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable read-only memory (EPROM), etc.

[0122] When the processor reads and runs the computer program instructions stored in the memory corresponding to the method for calculating the short-circuit ratio of multiple new energy power stations, it executes the method for calculating the short-circuit ratio of multiple new energy power stations provided in the embodiments of this application.

[0123] A processor may be an integrated circuit chip with signal processing capabilities. The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), discrete gate or transistor logic devices, or discrete hardware components.

[0124] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or equivalent to the scope of this invention are included in this invention.

Claims

1. A method for calculating the short-circuit ratio of multiple new energy power stations, characterized in that, include: The obtained upper-level power grid model and cross-section are spliced ​​together with the obtained local power grid model and cross-section to obtain power grid model one containing the external grid model; Perform network topology analysis on the power grid model 1 to obtain the total set of topology nodes. Wherein, the total set of power grid topology nodes Includes a set of topological nodes for new energy power stations ; Based on the equipment resistance, reactance parameters, and total topology node set of power grid model 1 Form the node admittance matrix of power grid model one, and process the node admittance matrix to obtain the factor table of the node admittance matrix; Calculate the set of topological nodes of the new energy power station in the node impedance matrix based on the factor table of the node admittance matrix. The self-impedance and mutual impedance of the corresponding nodes; Obtain the set of topological nodes of the new energy power station The short-circuit current of each node is calculated, and the short-circuit capacity of each node is obtained. Based on the short-circuit capacity of each node and The short-circuit ratio of each node is obtained by measuring its self-impedance and mutual impedance. Based on the short-circuit ratio of each node, the short-circuit ratio of multiple new energy power stations is obtained; and the set of topological nodes of the new energy power stations is obtained. The short-circuit current at each node also includes: Dynamically partition the power grid model to form a main power grid partition and N sub-power grid partitions; For power grids containing renewable energy power plants, power flow calculations are performed based on the actual output of all generators and loads, including those generating renewable energy, to obtain the voltage of all nodes under normal operating conditions. ; A power flow-based short-circuit current calculation method is used to obtain the topology node set of the new energy power station. When a three-phase short-circuit fault occurs at node f, the voltage of all nodes in the power grid ; Among them, the set of topological nodes of new energy power stations was obtained. When a three-phase short-circuit fault occurs at node f, the voltage of all nodes in the power grid include: When a three-phase short-circuit fault occurs at node f, and the voltage of the root node in the s-th sub-region of the power grid is less than the critical voltage, the output current of the new energy power source is obtained based on the voltage control characteristics of the new energy power source. When there is no new energy power source in the s-th sub-region of the power grid or the voltage of the root node is greater than the critical voltage, there is no need to modify the output current of the new energy power source in sub-region s. When the absolute value of the difference between the (k+1)-th voltage correction amount and the k-th voltage correction amount at node f is less than or equal to the set value, the output current correction amount of the new energy power source is obtained. Based on the voltage control characteristics of new energy power sources, and based on the voltage of all nodes in the power grid when a three-phase short-circuit fault occurs at node f. The output current correction of the new energy power source is calculated iteratively under the drop condition, and the voltage correction of all nodes in the power grid is solved. When the absolute value of the difference between the (k+1)th voltage correction and the kth voltage correction at node f is less than a set value, the voltages of all nodes in the power grid when a three-phase short circuit occurs at node f are obtained. .

2. The method for calculating the short-circuit ratio of multiple new energy power stations according to claim 1, characterized in that, The dynamic partitioning of power grid model one includes: The power grid model 1 is decomposed using the node splitting method; Based on the operation mode of power grid model one, dynamic partitioning is performed, dividing the power grid above 220kV / 330kV into the main power grid partition, and dividing the power grid below 220kV / 330kV into N sub-power grid partitions.

3. The method for calculating the short-circuit ratio of multiple new energy power stations according to claim 1, characterized in that, The formula for calculating the short-circuit ratio of the new energy multi-station is as follows: ； in: This refers to the topology node number of the new energy power station. For the first Short-circuit capacity of each new energy power station topology node; For the first The equivalent power of a new energy power station after considering the impact of other new energy power stations; The first node impedance matrix Z is the... OK, Column elements; The first node impedance matrix Z is the... Row and column j elements; For the first The power of a new energy power station connected to the grid is in the range of [missing information]. The power output of the j-th renewable energy power station connected to the grid is shown as [value].

4. The method for calculating the short-circuit ratio of multiple new energy power stations according to claim 1, characterized in that, The factor table for obtaining the node admittance matrix by processing the node admittance matrix includes: The node numbers in the node admittance matrix are reordered using an approximate minimum degree sorting method, and the factor table of the node admittance matrix is ​​calculated.

5. A short-circuit ratio calculation system for multiple new energy power stations, characterized in that, include: The splicing module is used to splice the acquired upper-level power grid model and cross-section with the acquired local power grid model and cross-section to obtain a power grid model one containing the external grid model; The topology analysis module is used to perform network topology analysis on the power grid model one to obtain the total set of topology nodes. Wherein, the total set of topology nodes Includes a set of topological nodes for new energy power stations ; The factor table generation module is used to generate the factor table based on the equipment resistance, reactance parameters, and total topology node set of the power grid model 1. Form the node admittance matrix of power grid model one, and process the node admittance matrix to obtain the factor table of the node admittance matrix; The impedance calculation module is used to calculate the set of topological nodes of new energy power stations in the node impedance matrix based on the factor table of the node admittance matrix. The self-impedance and mutual impedance of the corresponding nodes; The short-circuit capacity calculation module is used to obtain the set of topology nodes of the new energy power station. The short-circuit current of each node is calculated, and the short-circuit capacity of each node is obtained. The short-circuit ratio calculation module is used to calculate the short-circuit ratio based on the short-circuit capacity of each node and... The self-impedance and mutual impedance of each node are used to obtain the short-circuit ratio of each node; and this is used to obtain the short-circuit ratio of multiple new energy power stations based on the short-circuit ratio of each node; this is done when obtaining the topology node set of the new energy power station. The short-circuit current at each node also includes: Dynamically partition the power grid model to form a main power grid partition and N sub-power grid partitions; For power grids containing renewable energy power plants, power flow calculations are performed based on the actual output of all generators and loads, including those generating renewable energy, to obtain the voltage of all nodes under normal operating conditions. ; A power flow-based short-circuit current calculation method is used to obtain the topology node set of the new energy power station. When a three-phase short-circuit fault occurs at node f, the voltage of all nodes in the power grid Obtain the set of topological nodes for new energy power stations. When a three-phase short-circuit fault occurs at node f, the voltage of all nodes in the power grid include: When a three-phase short-circuit fault occurs at node f, and the voltage of the root node in the s-th sub-region of the power grid is less than the critical voltage, the output current of the new energy power source is obtained based on the voltage control characteristics of the new energy power source. When there is no new energy power source in the s-th sub-region of the power grid or the voltage of the root node is greater than the critical voltage, there is no need to modify the output current of the new energy power source in sub-region s. When the absolute value of the difference between the (k+1)-th voltage correction amount and the k-th voltage correction amount at node f is less than or equal to the set value, the output current correction amount of the new energy power source is obtained. Based on the voltage control characteristics of new energy power sources, and based on the voltage of all nodes in the power grid when a three-phase short-circuit fault occurs at node f. The output current correction of the new energy power source is calculated iteratively under the drop condition, and the voltage correction of all nodes in the power grid is solved. When the absolute value of the difference between the (k+1)th voltage correction and the kth voltage correction at node f is less than a set value, the voltages of all nodes in the power grid when a three-phase short circuit occurs at node f are obtained. .

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1-4.

7. An electronic device, characterized in that, Including processor and storage media; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1-4.

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