Limiting method and system for short-circuit current of power grid

Abstract

The invention discloses a method and a system for limiting short-circuit current of a power grid, which relate to the technical field of short-circuit current limitation and are used for acquiring a system topological structure of the power grid and acquiring node information of each node and electrical quantity parameters of each synchronous machine according to the system topological structure when the power grid has a short-circuit fault; performing three-phase short-circuit current analysis on the information of each node to obtain a three-phase short-circuit current corresponding to each node, screening all nodes by adopting each three-phase short-circuit current to obtain a plurality of standard-exceeding nodes, determining contribution factors corresponding to each synchronous machine according to the three-phase short-circuit current of each standard-exceeding node and each electrical quantity parameter, and determining the contribution factors of each synchronous machine according to the contribution factors. And screening the synchronous machines according to the contribution factors to obtain a plurality of target synchronous machines, and performing hot standby processing on the target synchronous machines to limit the short-circuit current of the power grid. The technical problem that the reliability of power grid operation is reduced due to the lack of clear indexes since which synchronous machines need to be subjected to hot standby are generally judged according to the experience of analysts in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of short-circuit current limitation, and in particular to a method and system for limiting short-circuit current of a power grid. Background Art

[0002] In the design and operation of power systems and electrical equipment, short-circuit calculation is an indispensable basic calculation for solving a series of technical problems. One of the main problems is to select electrical equipment with sufficient mechanical stability and thermal stability, such as circuit breakers, transformers, busbars, cables, etc., which must be based on short-circuit calculation. According to the calculation conclusions of the annual method and the three-year method of the Southern Power Grid, after considering the DC component, the number of plants and stations with short-circuit current exceeding the standard in the Guangdong Power Grid will be 13, 13, and 27 in 2024, 2025, and 2026. Therefore, the excessive short-circuit current has become one of the major risks that restrict the development of the power grid and affect the safety of the power grid.

[0003] The existing technology mainly uses hot standby synchronous machines to prevent the risk of excessive short-circuit current in the power grid. However, the judgment of which synchronous machines need to be hot-standby is generally based on the experience of analysts. There is a lack of clear indicators and the risk of human misjudgment, which reduces the reliability of power grid operation. Summary of the invention

[0004] The present invention provides a method and system for limiting short-circuit current of a power grid, which solves the technical problem that the prior art mainly uses hot standby synchronous machines to prevent the risk of excessive short-circuit current in the power grid, but the judgment of which synchronous machines need to be hot-standby is generally based on the experience of analysts, lacks clear indicators, and has the risk of human misjudgment, thereby reducing the reliability of power grid operation.

[0005] A first aspect of the present invention provides a method for limiting short-circuit current of a power grid, comprising:

[0006] Acquire a system topology structure of a power grid, and acquire node information of each node and electrical quantity parameters of each synchronous machine when a short circuit fault occurs in the power grid according to the system topology structure;

[0007] Performing three-phase short-circuit current analysis on each of the node information to obtain the three-phase short-circuit current corresponding to each of the nodes;

[0008] Using each of the three-phase short-circuit currents to screen all of the nodes, and obtaining a plurality of nodes exceeding the standard;

[0009] Determining the contribution factor corresponding to each of the synchronous machines according to the three-phase short-circuit current of each of the exceeding nodes and each of the electrical quantity parameters;

[0010] The synchronous machines are screened according to the contribution factors to obtain a plurality of target synchronous machines, and hot standby processing is performed on the target synchronous machines to limit the short-circuit current of the power grid.

[0011] Optionally, the node information includes node admittance and node initial voltage, and the step of performing three-phase short-circuit current analysis on each of the node information to obtain the three-phase short-circuit current corresponding to each of the nodes includes:

[0012] Constructing a node admittance matrix using each of the node admittances;

[0013] Performing matrix conversion processing on the node admittance matrix to obtain a node impedance matrix, and determining the node impedance corresponding to each of the nodes according to the node impedance matrix;

[0014] Respectively performing ratio processing on the node initial voltage and the node impedance corresponding to each of the nodes to obtain a first ratio corresponding to each of the nodes;

[0015] Each of the first ratios is multiplied by a preset voltage coefficient to obtain a three-phase short-circuit current corresponding to each of the nodes.

[0016] Optionally, the step of screening all the nodes using each of the three-phase short-circuit currents to obtain a plurality of nodes exceeding the standard includes:

[0017] Determine whether each of the three-phase short-circuit currents is greater than or equal to a preset short-circuit current exceeding threshold value;

[0018] When the three-phase short-circuit current is greater than or equal to the short-circuit current exceeding threshold, the node associated with the three-phase short-circuit current is regarded as an exceeding node.

[0019] Optionally, the step of determining the contribution factor corresponding to each of the synchronous machines according to the three-phase short-circuit current of each of the exceeding nodes and each of the electrical quantity parameters comprises:

[0020] Acquire the mutual impedance between each of the synchronous machines and each of the exceeding nodes;

[0021] Respectively multiplying the three-phase short-circuit current of each of the exceeding nodes by each of the mutual impedances to obtain a plurality of first multiplication values;

[0022] Performing difference processing on a preset voltage coefficient and each of the first multiplication values ​​respectively to obtain a node voltage value corresponding to each of the first multiplication values;

[0023] Contribution factors corresponding to the synchronous machines are determined according to the electrical quantity parameters, the three-phase short-circuit currents and node voltage values ​​associated with the electrical quantity parameters.

[0024] Optionally, the electrical quantity parameters include synchronous machine impedance and synchronous machine internal potential, and the step of determining the contribution factor corresponding to each of the synchronous machines according to each of the electrical quantity parameters, each of the three-phase short-circuit currents and the node voltage value associated with the electrical quantity parameters includes:

[0025] Performing difference processing on the internal potential of the synchronous machine and the node voltage value associated with each of the synchronous machines to obtain a plurality of first difference values;

[0026] Performing ratio processing on the first difference associated with each of the synchronous machines and the synchronous machine impedance respectively to obtain short-circuit currents contributed by the multiple synchronous machines;

[0027] Respectively performing ratio processing on the synchronous machine contribution short-circuit current and the three-phase short-circuit current associated with each of the synchronous machines to obtain a plurality of short-circuit current contribution coefficients;

[0028] The short-circuit current contribution coefficients associated with each of the synchronous machines are added up respectively to obtain the contribution factors corresponding to each of the synchronous machines.

[0029] Optionally, the step of screening each of the synchronous machines according to each of the contribution factors to obtain a plurality of target synchronous machines, and performing hot standby processing on each of the target synchronous machines to limit the short-circuit current of the power grid includes:

[0030] Arrange the contribution factors from large to small to obtain a contribution factor sequence;

[0031] Selecting the synchronous machine with the largest contribution factor from the contribution factor sequence as the target synchronous machine, and eliminating the contribution factors associated with the target synchronous machine in the contribution factor sequence;

[0032] Determine whether the number of the target synchronous machines is less than a preset hot standby number threshold;

[0033] If the number of the target synchronous machines is less than the hot standby number threshold, the step of selecting the synchronous machine with the largest contribution factor from the contribution factor sequence as the target synchronous machine and eliminating the contribution factor associated with the target synchronous machine in the contribution factor sequence is jumped to execution;

[0034] If the number of the target synchronous machines is greater than or equal to the hot standby number threshold, hot standby processing is performed on each of the target synchronous machines to limit the short-circuit current of the power grid.

[0035] A second aspect of the present invention provides a power grid short-circuit current limiting system, comprising:

[0036] A collection module, used to obtain a system topology structure of a power grid, and to obtain node information of each node and electrical quantity parameters of each synchronous machine when a short circuit fault occurs in the power grid according to the system topology structure;

[0037] A first analysis module is used to perform three-phase short-circuit current analysis on each of the node information to obtain the three-phase short-circuit current corresponding to each of the nodes;

[0038] A screening module, used to screen all the nodes using each of the three-phase short-circuit currents to obtain a plurality of nodes exceeding the standard;

[0039] A second analysis module is used to determine the contribution factor corresponding to each of the synchronous machines according to the three-phase short-circuit current of each of the exceeding nodes and each of the electrical quantity parameters;

[0040] The hot standby module is used to screen each of the synchronous machines according to each of the contribution factors to obtain multiple target synchronous machines, and perform hot standby processing on each of the target synchronous machines to limit the short-circuit current of the power grid.

[0041] A third aspect of the present invention provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for limiting short-circuit current of a power grid as described in any one of the above items.

[0042] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the method for limiting short-circuit current of a power grid as described in any one of the above items.

[0043] A fifth aspect of the present invention provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes the method for limiting the short-circuit current of a power grid as described in any one of the above items.

[0044] It can be seen from the above technical solutions that the present invention has the following advantages:

[0045] The present invention calculates the three-phase short-circuit current of each node of the power grid, thereby screening out the nodes that exceed the standard among the nodes, and then calculates the contribution factor of each synchronous machine through the three-phase short-circuit current of the node that exceeds the standard and the electrical quantity parameters of the synchronous machine, and judges the target synchronous machine that needs to be hot-standby processed according to the contribution factor of each synchronous machine. Compared with the traditional judgment method, the present invention overcomes the technical problems of the existing judgment based on the experience of analysts, lack of clear indicators, risk of human judgment errors, and reduced reliability of power grid operation. By calculating the contribution factor of each synchronous machine in the power grid, a basis is provided for the formulation of a hot standby plan for the power grid, thereby improving the reliability of power grid operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0047] Figure 1 A flowchart of a method for limiting short-circuit current of a power grid provided in Embodiment 1 of the present invention;

[0048] Figure 2 A flowchart of a method for limiting short-circuit current of a power grid provided in Embodiment 2 of the present invention;

[0049] Figure 3 An equivalent circuit diagram between a synchronous machine and a node provided in the second embodiment of the present invention;

[0050] Figure 4 A structural block diagram of a power grid short-circuit current limiting system provided in Embodiment 3 of the present invention;

[0051] Figure 5 This is a structural block diagram of an electronic device provided in Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0052] The embodiments of the present invention provide a method and system for limiting short-circuit current of a power grid, which are used to solve the technical problem that the prior art mainly uses hot standby synchronous machines to prevent the risk of excessive short-circuit current in the power grid, but which synchronous machines need to be hot-standby is generally judged based on the experience of analysts, lacks clear indicators, and has the risk of human misjudgment, thereby reducing the reliability of power grid operation.

[0053] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] See also Figure 1 , Figure 1 A flowchart of the steps of a method for limiting short-circuit current of a power grid provided in Embodiment 1 of the present invention.

[0055] The present invention provides a method for limiting short-circuit current of a power grid, comprising:

[0056] Step 101, obtaining a system topology structure of a power grid, and obtaining node information of each node and electrical quantity parameters of each synchronous machine when a short circuit fault occurs in the power grid according to the system topology structure;

[0057] System topology refers to the topological diagram of the physical connection relationship between various components in the power grid (such as generators, transformers, transmission lines, loads, etc.).

[0058] Node information refers to the node admittance and node initial voltage of the power grid node.

[0059] Electrical quantity parameters refer to the synchronous machine impedance and internal potential of the synchronous machine in the power grid.

[0060] In the embodiment of the present invention, the system topology of the power grid is obtained, and the node information of all nodes on the power grid and the electrical quantity parameters of all synchronous machines are obtained from the system topology.

[0061] Step 102: Perform three-phase short-circuit current analysis on each node information to obtain the three-phase short-circuit current corresponding to each node;

[0062] In an embodiment of the present invention, the node admittance of each node information is used to construct a node admittance matrix, and the node admittance matrix is ​​inverted to obtain a node impedance matrix of the power grid. The node impedance of each node is obtained from the node impedance matrix, and the node impedance and node initial voltage associated with each node are respectively input into a preset short-circuit current function to obtain the three-phase short-circuit current corresponding to each node.

[0063] It should be noted that the short-circuit current function is specifically:

[0064]

[0065] in, is the three-phase short-circuit current, is the voltage coefficient, is the initial node voltage, is the node impedance.

[0066] Step 103, using each three-phase short-circuit current to screen all nodes, and obtain multiple nodes exceeding the standard;

[0067] In an embodiment of the present invention, three-phase short-circuit currents greater than or equal to a preset short-circuit current exceeding threshold are selected from all three-phase short-circuit currents as target short-circuit currents, and nodes corresponding to each target short-circuit current are taken as exceeding nodes.

[0068] It should be noted that if all three-phase short-circuit currents are less than the short-circuit current exceeding the standard threshold, it means that there is no hidden danger of short-circuit current exceeding the standard in the power grid, and a monitoring result of hidden danger of power grid exceeding the standard is generated.

[0069] Step 104: Determine the contribution factor corresponding to each synchronous machine according to the three-phase short-circuit current of each exceeding-standard node and each electrical quantity parameter;

[0070] In an embodiment of the present invention, the mutual impedance between each synchronous machine and the exceeding node is obtained, and the electrical quantity parameters of each synchronous machine and the three-phase short-circuit current of each exceeding node are respectively input into a preset contribution factor function to obtain the contribution factor corresponding to each synchronous machine.

[0071] It should be noted that the contribution factor function is specifically:

[0072]

[0073] in, Contributes short-circuit current to synchronous machine i, is the internal potential of synchronous machine i, is the voltage between the synchronous machine i and the exceeding node g, is the synchronous machine impedance of synchronous machine i, is the voltage coefficient (usually 1.08-1.10), is the three-phase short-circuit current, is the mutual impedance between node f and synchronizer i, is the contribution factor of synchronous machine i.

[0074] Step 105 , screen each synchronous machine according to each contribution factor to obtain a plurality of target synchronous machines, and perform hot standby processing on each target synchronous machine to limit the short-circuit current of the power grid.

[0075] In the embodiment of the present invention, the synchronous machines are sorted from large to small according to their contribution factors, a preset number of hot standby synchronous machines are selected as target synchronous machines, and hot standby processing is performed on each target synchronous machine to limit the short-circuit current of the power grid.

[0076] It should be noted that the hot standby processing refers to cutting off the target synchronous machine and putting the hot standby synchronous machine into use to limit the short-circuit current of the power grid.

[0077] In an embodiment of the present invention, the three-phase short-circuit current of each node of the power grid is calculated, thereby screening out the nodes that exceed the standard among the nodes, and then calculating the contribution factor of each synchronous machine through the three-phase short-circuit current of the node that exceeds the standard and the electrical quantity parameters of the synchronous machine, and judging the target synchronous machine that needs to be hot-standby according to the contribution factor of each synchronous machine. Compared with the traditional judgment method, the present invention overcomes the technical problems of the existing judgment based on the experience of analysts, lack of clear indicators, risk of human judgment errors, and reduced reliability of power grid operation. By calculating the contribution factor of each synchronous machine in the power grid, a basis is provided for formulating a hot standby plan for the power grid, thereby improving the reliability of power grid operation.

[0078] See also Figure 2 , Figure 2 A flowchart of the steps of a method for limiting short-circuit current of a power grid provided in Embodiment 2 of the present invention.

[0079] The present invention provides a method for limiting short-circuit current of a power grid, comprising:

[0080] Step 201, obtaining a system topology structure of a power grid, and obtaining node information of each node and electrical quantity parameters of each synchronous machine when a short circuit fault occurs in the power grid according to the system topology structure;

[0081] In the embodiment of the present invention, the system topology of the power grid is acquired, and the node information of each node and the electrical quantity parameters of each synchronous machine when a short circuit fault occurs in the power grid are extracted from the system topology.

[0082] Step 202: Perform three-phase short-circuit current analysis on each node information to obtain the three-phase short-circuit current corresponding to each node;

[0083] Further, the node information includes node admittance and node initial voltage, and step 202 includes the following sub-steps:

[0084] S11, constructing a node admittance matrix using the admittance of each node;

[0085] In the embodiment of the present invention, the node admittance matrix is ​​constructed using the node admittance of each node.

[0086] It should be noted that the node admittance matrix is ​​specifically:

[0087]

[0088] in, is the node admittance matrix, is the self-admittance of node n, is the admittance between node i and node j.

[0089] S12, performing matrix conversion processing on the node admittance matrix to obtain a node impedance matrix, and determining the node impedance corresponding to each node according to the node impedance matrix;

[0090] In the embodiment of the present invention, a matrix inversion operation is performed on the node admittance matrix to obtain a node impedance matrix, and the node impedance corresponding to each node is extracted from the node impedance matrix.

[0091] It should be noted that the node impedance matrix is ​​specifically:

[0092]

[0093] in, is the node impedance matrix, is the self-impedance of node n, is the impedance between node i and node j.

[0094] S13, performing ratio processing on the node initial voltage and the node impedance corresponding to each node to obtain a first ratio corresponding to each node;

[0095] In the embodiment of the present invention, a ratio operation is performed on the node initial voltage and the node impedance corresponding to each node to obtain a first ratio corresponding to each node.

[0096] It should be noted that the node initial voltage refers to the initial voltage immediately before the node fails.

[0097] S14, multiplying each first ratio by a preset voltage coefficient to obtain a three-phase short-circuit current corresponding to each node.

[0098] In the embodiment of the present invention, each first ratio is multiplied by a preset voltage coefficient to obtain a three-phase short-circuit current corresponding to each node.

[0099] It is worth mentioning that the preset voltage coefficient is generally 1.08-1.1.

[0100] Step 203: determine whether each three-phase short-circuit current is greater than or equal to a preset short-circuit current exceeding standard threshold;

[0101] In the embodiment of the present invention, it is determined whether each three-phase short-circuit current is greater than or equal to a preset short-circuit current exceeding threshold value. If each three-phase short-circuit current is less than the short-circuit current exceeding threshold value, there is no need to perform hot standby on the synchronous machine.

[0102] It should be noted that for 500kV nodes, 61kA is generally taken as the short-circuit current exceeding the standard threshold; for 220kV nodes, 48kA is generally taken as the short-circuit current exceeding the standard threshold.

[0103] Step 204: When the three-phase short-circuit current is greater than or equal to the short-circuit current exceeding threshold, the node associated with the three-phase short-circuit current is regarded as an exceeding node.

[0104] In the embodiment of the present invention, when the three-phase short-circuit current is greater than or equal to the short-circuit current exceeding threshold, the node associated with the three-phase short-circuit current is marked as an exceeding node.

[0105] Step 205: Determine the contribution factor corresponding to each synchronous machine according to the three-phase short-circuit current of each exceeding-standard node and each electrical quantity parameter;

[0106] Further, step 205 includes the following sub-steps:

[0107] S21, obtaining the mutual impedance between each synchronous machine and each exceeding-standard node;

[0108] In the embodiment of the present invention, the mutual impedance between each synchronous machine and each exceeding-standard node is obtained from the system topology of the power grid.

[0109] S22, respectively multiplying the three-phase short-circuit current of each exceeding-standard node by each mutual impedance to obtain a plurality of first multiplication values;

[0110] In the embodiment of the present invention, the three-phase short-circuit current of each exceeding-standard node is multiplied by each mutual impedance to obtain a plurality of first multiplication values.

[0111] S23, performing difference processing on the preset voltage coefficient and each first multiplication value respectively to obtain a node voltage value corresponding to each first multiplication value;

[0112] In the embodiment of the present invention, the preset voltage coefficient and each first multiplication value are respectively subjected to difference processing to obtain the node voltage value between each synchronous machine and each exceeding-standard node.

[0113] S24. Determine the contribution factor corresponding to each synchronous machine according to each electrical quantity parameter, each three-phase short-circuit current and the node voltage value associated with the electrical quantity parameter.

[0114] Furthermore, the electrical quantity parameters include synchronous machine impedance and synchronous machine internal potential, and S24 includes the following sub-steps:

[0115] S241, performing difference processing on the internal potential of each synchronous machine and the node voltage value associated with each synchronous machine to obtain a plurality of first difference values;

[0116] In the embodiment of the present invention, a difference operation is performed on the internal potential of the synchronous machine associated with each synchronous machine and the node voltage value to obtain a plurality of first difference values.

[0117] S242, performing ratio processing on the first difference associated with each synchronous machine and the synchronous machine impedance respectively to obtain short-circuit current contributed by the multiple synchronous machines;

[0118] In the embodiment of the present invention, a ratio operation is performed between the first difference associated with each synchronous machine and the synchronous machine impedance to obtain the short-circuit current contributed by the multiple synchronous machines.

[0119] S243, performing ratio processing on the synchronous machine contribution short-circuit current and the three-phase short-circuit current associated with each synchronous machine to obtain a plurality of short-circuit current contribution coefficients;

[0120] In the embodiment of the present invention, a ratio operation is performed on the synchronous machine contribution short-circuit current associated with each synchronous machine and the three-phase short-circuit current to obtain a plurality of short-circuit current contribution coefficients.

[0121] S244, respectively summing up the short-circuit current contribution coefficients associated with each synchronous machine to obtain a contribution factor corresponding to each synchronous machine.

[0122] In the embodiment of the present invention, the short-circuit current contribution coefficients associated with each synchronous machine are added together to obtain the contribution factor corresponding to each synchronous machine.

[0123] In another embodiment, the contribution factor of each synchronous machine is calculated, wherein the contribution factor calculation process is specifically as follows: the grid-connected node of synchronous machine i is Gi, and its equivalent circuit is a Thevenin circuit in which a voltage source and an impedance are connected in series. Figure 3 As shown, when the three-phase short circuit occurs at node f, the synchronous machine i contributes the short-circuit current for:

[0124]

[0125] According to the contribution factor function, when the three-phase short circuit occurs at node f, the short-circuit current contribution coefficient of synchronous machine i can be expressed as:

[0126]

[0127] For each exceeding node, the contribution factor of synchronous machine i can be expressed as:

[0128]

[0129] In the formula, , , are the mutual impedances between the exceeding nodes 1, 2, m and the synchronous machine i, , , are the self-impedances of the exceeding nodes 1, 2, and m respectively.

[0130] Step 206: Screen each synchronous machine according to each contribution factor to obtain multiple target synchronous machines, and perform hot standby processing on each target synchronous machine to limit the short-circuit current of the power grid.

[0131] Further, step 206 includes the following sub-steps:

[0132] S31, sorting the contribution factors from large to small to obtain a contribution factor sequence;

[0133] In the embodiment of the present invention, the contribution factors are sorted from large to small to obtain a contribution factor sequence.

[0134] S32, selecting a synchronous machine with the largest contribution factor from the contribution factor sequence as the target synchronous machine, and eliminating the contribution factors associated with the target synchronous machine in the contribution factor sequence;

[0135] In the embodiment of the present invention, the maximum contribution factor is selected from the contribution factor sequence as the target contribution factor, the target contribution factor in the contribution factor sequence is eliminated, and the synchronous machine associated with the target contribution factor is used as the target synchronous machine.

[0136] S33, determining whether the number of target synchronous machines is less than a preset hot standby number threshold;

[0137] S34, if the number of target synchronous machines is less than the hot standby number threshold, jump to the step of selecting the synchronous machine with the largest contribution factor from the contribution factor sequence as the target synchronous machine, and eliminating the contribution factor associated with the target synchronous machine in the contribution factor sequence;

[0138] In an embodiment of the present invention, it is determined whether the number of target synchronous machines is less than a preset hot standby number threshold. If the number of target synchronous machines is less than the hot standby number threshold, the process jumps to S32-S33 until the number of target synchronous machines is greater than or equal to the hot standby number threshold.

[0139] S35. If the number of target synchronous machines is greater than or equal to the hot standby number threshold, hot standby processing is performed on each target synchronous machine to limit the short-circuit current of the power grid.

[0140] In the embodiment of the present invention, if the number of target synchronous machines is greater than or equal to the hot standby number threshold, hot standby operation is performed on each target synchronous machine to limit the short-circuit current of the power grid.

[0141] In an embodiment of the present invention, the three-phase short-circuit current of each node of the power grid is calculated, thereby screening out the nodes that exceed the standard among the nodes, and then calculating the contribution factor of each synchronous machine through the three-phase short-circuit current of the node that exceeds the standard and the electrical quantity parameters of the synchronous machine, and judging the target synchronous machine that needs to be hot-standby according to the contribution factor of each synchronous machine. Compared with the traditional judgment method, the present invention overcomes the technical problems of the existing judgment based on the experience of analysts, lack of clear indicators, risk of human judgment errors, and reduced reliability of power grid operation. By calculating the contribution factor of each synchronous machine in the power grid, a basis is provided for formulating a hot standby plan for the power grid, thereby improving the reliability of power grid operation.

[0142] See also Figure 4 , Figure 4 This is a structural block diagram of a power grid short-circuit current limiting system provided in Embodiment 3 of the present invention.

[0143] The present invention provides a power grid short-circuit current limiting system, comprising:

[0144] The acquisition module 301 is used to obtain the system topology of the power grid, and obtain the node information of each node and the electrical quantity parameters of each synchronous machine when a short circuit fault occurs in the power grid according to the system topology;

[0145] The first analysis module 302 is used to perform three-phase short-circuit current analysis on each node information to obtain the three-phase short-circuit current corresponding to each node;

[0146] A screening module 303 is used to screen all nodes using each three-phase short-circuit current to obtain multiple nodes that exceed the standard;

[0147] The second analysis module 304 is used to determine the contribution factor corresponding to each synchronous machine according to the three-phase short-circuit current and various electrical quantity parameters of each exceeding-standard node;

[0148] The hot standby module 305 is used to screen each synchronous machine according to each contribution factor to obtain multiple target synchronous machines, and perform hot standby processing on each target synchronous machine to limit the short-circuit current of the power grid.

[0149] Furthermore, the first analysis module 302 includes:

[0150] A construction submodule is used to construct a node admittance matrix using each node admittance;

[0151] The matrix conversion submodule is used to perform matrix conversion processing on the node admittance matrix to obtain the node impedance matrix, and determine the node impedance corresponding to each node according to the node impedance matrix;

[0152] A first ratio submodule, used for performing ratio processing on the node initial voltage and the node impedance corresponding to each node to obtain a first ratio corresponding to each node;

[0153] The three-phase short-circuit current submodule is used to multiply each first ratio by a preset voltage coefficient to obtain a three-phase short-circuit current corresponding to each node.

[0154] Furthermore, the screening module 303 includes:

[0155] The first analysis submodule is used to determine whether each three-phase short-circuit current is greater than or equal to a preset short-circuit current exceeding standard threshold;

[0156] The screening submodule is used to treat the nodes associated with the three-phase short-circuit current as exceeding-standard nodes when the three-phase short-circuit current is greater than or equal to the short-circuit current exceeding-standard threshold.

[0157] Furthermore, the second analysis module 304 includes:

[0158] The acquisition submodule is used to obtain the mutual impedance between each synchronous machine and each exceeding-standard node;

[0159] The second analysis submodule is used to multiply the three-phase short-circuit current of each exceeding-standard node by each mutual impedance to obtain a plurality of first multiplication values;

[0160] Performing difference processing on the preset voltage coefficient and each first multiplication value respectively to obtain the node voltage value corresponding to each first multiplication value;

[0161] The third analysis submodule is used to determine the contribution factor corresponding to each synchronous machine according to each electrical quantity parameter, each three-phase short-circuit current and the node voltage value associated with the electrical quantity parameter.

[0162] Furthermore, the electrical quantity parameters include synchronous machine impedance and synchronous machine internal potential. The third analysis submodule includes:

[0163] A difference unit, used for performing difference processing on the internal potential of the synchronous machine and the node voltage value associated with each synchronous machine to obtain a plurality of first difference values;

[0164] A first ratio unit is used to perform ratio processing on the first difference associated with each synchronous machine and the synchronous machine impedance to obtain short-circuit currents contributed by the multiple synchronous machines;

[0165] A second ratio unit is used to perform ratio processing on the synchronous machine contribution short-circuit current and the three-phase short-circuit current associated with each synchronous machine to obtain a plurality of short-circuit current contribution coefficients;

[0166] The adding unit is used to add up the short-circuit current contribution coefficients associated with each synchronous machine to obtain the contribution factor corresponding to each synchronous machine.

[0167] Furthermore, the hot standby module 305 includes:

[0168] A sorting submodule is used to sort the contribution factors from large to small to obtain a contribution factor sequence;

[0169] A selection submodule is used to select a synchronous machine with the largest contribution factor from the contribution factor sequence as a target synchronous machine, and to eliminate the contribution factors associated with the target synchronous machine in the contribution factor sequence;

[0170] A fourth analysis submodule is used to determine whether the number of target synchronous machines is less than a preset hot standby number threshold;

[0171] If the number of target synchronous machines is less than the hot standby number threshold, the process jumps to the step of selecting a synchronous machine with the largest contribution factor from the contribution factor sequence as the target synchronous machine, and eliminating the contribution factor associated with the target synchronous machine in the contribution factor sequence;

[0172] If the number of target synchronous machines is greater than or equal to the hot standby number threshold, hot standby processing is performed on each target synchronous machine to limit the short-circuit current of the power grid.

[0173] See also Figure 5 , Figure 5 This is a structural block diagram of an electronic device provided in Embodiment 4 of the present invention.

[0174] An electronic device according to an embodiment of the present invention includes: a memory 401 and a processor 402, wherein the memory 402 stores a computer program; when the computer program is executed by the processor 402, the processor 402 executes a method for limiting short-circuit current of a power grid as described in any of the above embodiments.

[0175] The memory 401 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read-only memory), an EPROM, a hard disk or a ROM. The memory 401 has a storage space 403 for a program code 413 for executing any method step in the above method. For example, the storage space 403 for the program code may include individual program codes 413 for implementing the various steps in the above method, respectively. These program codes may be read from or written to one or more computer program products. These computer program products include program code carriers such as a hard disk, a compact disk (CD), a memory card or a floppy disk. The program code may be compressed, for example, in an appropriate form. When these codes are run by a computing and processing device, the computing and processing device is caused to execute the various steps in the above-described method.

[0176] Embodiment 5 of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the method for limiting the short-circuit current of a power grid as described in any of the above embodiments is implemented.

[0177] Embodiment 6 of the present invention further provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes a method for limiting the short-circuit current of a power grid as described in any of the above embodiments.

[0178] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0179] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0180] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0181] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0182] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0183] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for limiting short-circuit current in a power grid, characterized in that: include: Acquire a system topology structure of a power grid, and acquire node information of each node and electrical quantity parameters of each synchronous machine when a short circuit fault occurs in the power grid according to the system topology structure; Performing three-phase short-circuit current analysis on each of the node information to obtain the three-phase short-circuit current corresponding to each of the nodes; Using each of the three-phase short-circuit currents to screen all of the nodes, a plurality of nodes exceeding the standard are obtained; Determining the contribution factor corresponding to each of the synchronous machines according to the three-phase short-circuit current of each of the exceeding nodes and each of the electrical quantity parameters; The synchronous machines are screened according to the contribution factors to obtain a plurality of target synchronous machines, and hot standby processing is performed on the target synchronous machines to limit the short-circuit current of the power grid.

2. The method for limiting short-circuit current of a power grid according to claim 1, characterized in that: The node information includes node admittance and node initial voltage. The step of performing three-phase short-circuit current analysis on each of the node information to obtain the three-phase short-circuit current corresponding to each of the nodes includes: Constructing a node admittance matrix using each of the node admittances; Performing matrix conversion processing on the node admittance matrix to obtain a node impedance matrix, and determining the node impedance corresponding to each of the nodes according to the node impedance matrix; Respectively performing ratio processing on the node initial voltage and the node impedance corresponding to each of the nodes to obtain a first ratio corresponding to each of the nodes; Each of the first ratios is multiplied by a preset voltage coefficient to obtain a three-phase short-circuit current corresponding to each of the nodes.

3. The method for limiting short-circuit current of a power grid according to claim 1, characterized in that: The step of using each of the three-phase short-circuit currents to screen all the nodes to obtain a plurality of nodes exceeding the standard includes: Determine whether each of the three-phase short-circuit currents is greater than or equal to a preset short-circuit current exceeding threshold value; When the three-phase short-circuit current is greater than or equal to the short-circuit current exceeding threshold, the node associated with the three-phase short-circuit current is regarded as an exceeding node.

4. The method for limiting short-circuit current of a power grid according to claim 1, characterized in that: The step of determining the contribution factor corresponding to each of the synchronous machines according to the three-phase short-circuit current of each of the exceeding nodes and each of the electrical quantity parameters comprises: Acquire the mutual impedance between each of the synchronous machines and each of the exceeding nodes; Respectively multiplying the three-phase short-circuit current of each of the exceeding nodes by each of the mutual impedances to obtain a plurality of first multiplication values; Performing difference processing on a preset voltage coefficient and each of the first multiplication values ​​respectively to obtain a node voltage value corresponding to each of the first multiplication values; Contribution factors corresponding to the synchronous machines are determined according to the electrical quantity parameters, the three-phase short-circuit currents and node voltage values ​​associated with the electrical quantity parameters.

5. The method for limiting short-circuit current of a power grid according to claim 4, characterized in that: The electrical quantity parameters include synchronous machine impedance and synchronous machine internal potential, and the step of determining the contribution factor corresponding to each synchronous machine according to each of the electrical quantity parameters, each of the three-phase short-circuit currents and the node voltage value associated with the electrical quantity parameters includes: Performing difference processing on the internal potential of the synchronous machine and the node voltage value associated with each of the synchronous machines to obtain a plurality of first difference values; Performing ratio processing on the first difference associated with each of the synchronous machines and the synchronous machine impedance respectively to obtain short-circuit currents contributed by the multiple synchronous machines; Respectively performing ratio processing on the synchronous machine contribution short-circuit current and the three-phase short-circuit current associated with each of the synchronous machines to obtain a plurality of short-circuit current contribution coefficients; The short-circuit current contribution coefficients associated with each of the synchronous machines are added up respectively to obtain the contribution factors corresponding to each of the synchronous machines.

6. The method for limiting short-circuit current of a power grid according to claim 1, characterized in that: The step of screening each of the synchronous machines according to each of the contribution factors to obtain a plurality of target synchronous machines, and performing hot standby processing on each of the target synchronous machines to limit the short-circuit current of the power grid includes: Arrange the contribution factors from large to small to obtain a contribution factor sequence; Selecting the synchronous machine with the largest contribution factor from the contribution factor sequence as the target synchronous machine, and eliminating the contribution factors associated with the target synchronous machine in the contribution factor sequence; Determine whether the number of the target synchronous machines is less than a preset hot standby number threshold; If the number of the target synchronous machines is less than the hot standby number threshold, the step of selecting the synchronous machine with the largest contribution factor from the contribution factor sequence as the target synchronous machine and eliminating the contribution factor associated with the target synchronous machine in the contribution factor sequence is jumped to execution; If the number of the target synchronous machines is greater than or equal to the hot standby number threshold, hot standby processing is performed on each of the target synchronous machines to limit the short-circuit current of the power grid.

7. A power grid short-circuit current limiting system, characterized in that: include: A collection module, used to obtain a system topology structure of a power grid, and to obtain node information of each node and electrical quantity parameters of each synchronous machine when a short circuit fault occurs in the power grid according to the system topology structure; A first analysis module is used to perform three-phase short-circuit current analysis on each of the node information to obtain the three-phase short-circuit current corresponding to each of the nodes; A screening module, used to screen all the nodes using each of the three-phase short-circuit currents to obtain a plurality of nodes exceeding the standard; A second analysis module is used to determine the contribution factor corresponding to each of the synchronous machines according to the three-phase short-circuit current of each of the exceeding nodes and each of the electrical quantity parameters; The hot standby module is used to screen each of the synchronous machines according to each of the contribution factors to obtain multiple target synchronous machines, and perform hot standby processing on each of the target synchronous machines to limit the short-circuit current of the power grid.

8. An electronic device, characterized in that: The method comprises a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the method for limiting short-circuit current of a power grid as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the method for limiting short-circuit current of a power grid as claimed in any one of claims 1 to 6 is implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program stored on a non-transitory computer-readable storage medium, wherein the computer program comprises program instructions, wherein when the program instructions are executed by a computer, the computer is caused to execute the method for limiting short-circuit current of a power grid as claimed in any one of claims 1 to 6.

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