A power grid key section searching method, device and equipment and storage medium

Abstract

The application discloses a kind of power grid key section search method, device, equipment and storage medium, the method includes: obtaining first power grid network topology diagram, extract and delete the line of suspension node in first power grid network topology diagram and connect with suspension node, obtain second power grid network topology diagram;Search the cut point in second power grid network topology diagram, and divide second power grid network topology diagram into several subgraphs by cut point;Obtain the heavy load line in second power grid network topology diagram, judge the subgraph where the heavy load line is located;With heavy load line as root node, search first shortest path in subgraph and build key section search tree, traverse the key section search tree, obtain the key section of power grid.The method provided by the application has the characteristics of simplicity, efficiency, parallelism, etc., which can indirectly search the key section of power grid, can consider the accuracy and search efficiency of search result, and can get the key section with cut-set property.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power grid static stability analysis and identification, and particularly relates to a power grid key section searching method, device, equipment and storage medium. BACKGROUND

[0002] The key section of the power grid is an important link that is particularly concerned in power system dispatching. A small number of line breaks in the key section can cause a large amount of power flow transfer in the section, overloading the remaining lines and threatening the safe and stable operation of the power grid.

[0003] With large-scale new energy access, the volatility of new energy output causes the variability of power flow in the power grid, so that the key section also changes with the power flow. Therefore, fast and accurate searching of the key section is conducive to timely discovery of possible operation risks of the power grid in the new energy high penetration scenario, and timely adoption of control measures to reduce or avoid losses.

[0004] The current key section searching methods are mainly divided into node level and branch level. The node level method divides nodes into communities and combines the connection lines between the communities as the key section. This method requires a large number of iterations and matrix operations for clustering and division, and does not have online application capability in large power grids. The branch level method considers the power flow transfer path and the sensitivity of power flow break between lines after line fault, and selects lines on the power flow transfer path and the fault line to form the key section. Common methods include the first K shortest path algorithm and the away path searching algorithm. Although this method improves the searching efficiency of the key section, the section result obtained usually does not have the cut set property, and the setting of parameters in the search can easily affect the search effect of the algorithm. SUMMARY

[0005] Therefore, a power grid key section searching method, device, equipment and storage medium are provided, which solve the problems of the existing power grid key section searching method, such as complexity, inability to balance the accuracy and efficiency of the search result, and inability to obtain a key section with the cut set property.

[0006] The power grid key section searching method provided by the embodiment of the present application comprises:

[0007] A first power grid network topology graph is obtained, suspended nodes and lines connected to the suspended nodes in the first power grid network topology graph are extracted and deleted, a second power grid network topology graph is obtained, and the suspended nodes are nodes with a degree of 1;

[0008] Cut points in the second power grid network topology graph are searched, and the second power grid network topology graph is divided into a plurality of subgraphs through the cut points, and the cut points are nodes that cause the second power grid network topology graph to be unable to be connected after being deleted.

[0009] obtaining an overload line in the second power grid network topology, judging a subgraph in which the overload line is located, the overload line being a line with a load rate exceeding a preset threshold;

[0010] taking the overload line as a root node, constructing a key section search tree in the subgraph by searching a first shortest path, traversing the key section search tree, and obtaining the key section of the power grid.

[0011] Further, the taking the overload line as the root node and constructing the key section search tree in the subgraph by searching the first shortest path comprises:

[0012] judging the subgraph in which the overload line is located, deleting the overload line in the subgraph, and recording a first head node and a first tail node of the overload line;

[0013] obtaining a first shortest path (Dijkstra algorithm) between the first head node and the first tail node, and extracting all first lines in the first shortest path in a direction from the first head node to the first tail node;

[0014] obtaining a first level leaf node of the root node according to a positive direction of the first line and a power flow direction of the first line, starting from the first level leaf node, sequentially traversing the newly added leaf nodes, extending the leaf nodes by searching a shortest side path of the leaf nodes, wherein the positive direction of the first line is an order in which the first line nodes appear;

[0015] sequentially traversing all the overload lines to obtain the key section search tree of the power grid.

[0016] Further, the obtaining the first level leaf node of the root node according to the positive direction of the first line and the power flow direction of the first line comprises:

[0017] judging whether the positive direction of the first line is consistent with the power flow direction of the first line;

[0018] if the positive direction of the first line is consistent with the power flow direction of the first line, taking the first line as the first level leaf node of the root node.

[0019] Further, the starting from the first level leaf node, traversing the newly added leaf nodes, and extending the leaf nodes by searching the shortest side path of the leaf nodes comprises:

[0020] deleting the first line corresponding to the leaf node in the subgraph, detecting connectivity of the subgraph, and obtaining a connectivity result of the subgraph;

[0021] According to the connectivity result, the leaf node is extended.

[0022] Further, the extending the leaf node according to the connectivity result comprises:

[0023] If the subgraph is not connected, the extension of the leaf node is stopped;

[0024] If the subgraph is connected, a shortest side path of a first line corresponding to the leaf node is searched, whether a power flow direction of a second line in the shortest side path is consistent with a positive direction of the second line is judged, if consistent, the second line is taken as a next level leaf node of the leaf node, wherein the positive direction of the second line is an appearance order of the second line node.

[0025] Further, the searching the shortest side path of the first line corresponding to the leaf node comprises:

[0026] An upstream contact node downstream contact node is set in an upstream node set of the first shortest path;

[0027] All nodes in the upstream node set are connected with the upstream contact node, all nodes in a downstream node set are connected with the downstream contact node, a second shortest path between the upstream contact node and the downstream contact node is searched;

[0028] The first head node and the first tail node of the overloaded line, the upstream contact node and the downstream contact node in the second shortest path are deleted, a path composed of remaining nodes is the shortest side path of the first line.

[0029] Further, if a third line connecting a first node and a second node is disconnected, a path connecting the first node and the second node is stored, the path is a side path of the third line.

[0030] Further, a second head node and a node before the second head node of the first line in the first shortest path constitute the upstream node set, a second tail node and a node after the second tail node of the first line in the first shortest path constitute the downstream node set.

[0031] Further, the traversing the key section search tree to obtain the key section of the power grid comprises:

[0032] Starting from a root node of the key section search tree, walking along a path to the end, and then backtracking from a leaf node at the end of the path to a previous leaf node;

[0033] If there is no other leaf node at the previous leaf node except the leaf node at the end of the path, then backtrack up;

[0034] If there is other leaf node at the previous leaf node except the leaf node at the end of the path, then traverse other leaf nodes from the previous leaf node;

[0035] Continuously recursively repeat the process until all nodes are traversed, and each branch of the key section search tree is obtained, each branch being a group of cut-set type key sections.

[0036] The embodiment of the present application also provides an electric grid key section searching device, which comprises:

[0037] An acquisition module is configured to acquire a first electric grid network topology graph, extract and delete a hanging node and a line connected with the hanging node in the first electric grid network topology graph, and obtain a second electric grid network topology graph, wherein the hanging node is a node with a degree of one.

[0038] A division module is configured to search for a cut point in the second electric grid network topology graph, divide the second electric grid network topology graph into a plurality of subgraphs through the cut point, and the cut point is a node that causes the second electric grid network topology graph to be unable to be connected after being deleted.

[0039] A judgment module is configured to acquire an overload line in the second electric grid network topology graph, and judge a subgraph where the overload line is located, wherein the overload line is a line with a load rate exceeding a preset threshold.

[0040] A searching module is configured to take the overload line as a root node, construct a key section search tree in the subgraph through searching for a first shortest path, traverse the key section search tree, and acquire the key section of the electric grid.

[0041] The embodiment of the present application also provides an electric grid key section searching device, which comprises a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor to enable the processor to perform the following steps:

[0042] A first electric grid network topology graph is acquired, a hanging node and a line connected with the hanging node in the first electric grid network topology graph are extracted and deleted, and a second electric grid network topology graph is obtained, wherein the hanging node is a node with a degree of one.

[0043] A cut point in the second electric grid network topology graph is searched, and the second electric grid network topology graph is divided into a plurality of subgraphs through the cut point, wherein the cut point is a node that causes the second electric grid network topology graph to be unable to be connected after being deleted.

[0044] acquire a heavy load line in the second power grid network topology graph, judge the sub-graph where the heavy load line is located, the heavy load line is a line whose load rate exceeds a preset threshold;

[0045] take the heavy load line as a root node, construct a key section search tree in the sub-graph by searching a first shortest path, traverse the key section search tree, and acquire the key section of the power grid.

[0046] The embodiment of the application further provides a computer readable storage medium which stores a computer program, and the computer program is executed by a processor to make the processor execute the following steps:

[0047] acquire a first power grid network topology graph, extract and delete a hanging node and a line connected with the hanging node in the first power grid network topology graph, and obtain a second power grid network topology graph, the hanging node is a node with a degree of one;

[0048] search for a cut point in the second power grid network topology graph, divide the second power grid network topology graph into a plurality of sub-graphs through the cut point, and the cut point is a node which causes the second power grid network topology graph to be unable to be connected after being deleted;

[0049] acquire a heavy load line in the second power grid network topology graph, judge the sub-graph where the heavy load line is located, the heavy load line is a line whose load rate exceeds a preset threshold;

[0050] take the heavy load line as a root node, construct a key section search tree in the sub-graph by searching a first shortest path, traverse the key section search tree, and acquire the key section of the power grid.

[0051] The embodiment of the application has the following beneficial effects:

[0052] By deleting the hanging node in the power grid network topology graph, the power grid network topology graph is contracted, the power grid network topology graph after contraction is divided into a plurality of sub-graphs through the cut point, the calculation amount when constructing the key section search tree is reduced, the line with a higher load rate in the power grid network topology graph is taken as a search starting point, the shortest path is obtained by searching the shortest side path, the key section search tree is constructed, the key section with the cut set property of the power grid is acquired through the key section search tree, and the key section search tree is simple to construct. The search of the shortest side path is realized through the shortest path search between two nodes, the search time is short, the application has the characteristics of simplicity, efficiency and parallelism, the search of the key section of the power grid is indirect, the accuracy of the search result and the search efficiency can be considered, and the key section with the cut set property can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only aim to some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0054] Wherein:

[0055] Figure 1 A flowchart of a power grid key section search method provided by the embodiment of the present application is shown in the figure.

[0056] Figure 2 A topological structure diagram of an IEEE39 node system is shown in the figure.

[0057] Figure 3 A topological structure diagram of a second power grid network is shown in the figure. Figure 2 A corresponding second power grid network topological structure diagram is shown in the figure.

[0058] Figure 4 (a) is a diagram of one of the subgraphs obtained by dividing the second power grid network topological graph in (b) through cut points. Figure 3

[0059] Figure 4 (b) is a diagram of another subgraph obtained by dividing the second power grid network topological graph in (a) through cut points. Figure 3

[0060] Figure 5 A diagram of a key section search tree constructed with line 17 as a root node is shown in the figure. Figure 4

[0061] A flowchart of constructing a key section search tree in a subgraph through searching a first shortest path with an overload line as a root node is shown in the figure. Figure 6

[0062] A diagram of constructing a first level leaf node from a power grid topological graph with an overload line l as a root node is shown in the figure. Figure 7

[0063] A diagram of constructing a next level leaf node of the overload line l in (a) is shown in the figure. Figure 8 Figure 7 A diagram of the final key section search tree constructed by the overload line l in (a) is shown in the figure.

[0064] Figure 9 Figure 7 A diagram of constructing an upstream tie-in node and a downstream tie-in node in the shortest path of the root node l is shown in the figure.

[0065] Figure 10 A diagram of constructing an upstream tie-in node and a downstream tie-in node in the shortest path of the root node l is shown in the figure. ​​​​

[0066] Figure 11 An example of a side path;

[0067] Figure 12 A structural schematic diagram of a power grid key section searching device provided by an embodiment of the present application;

[0068] Figure 13 A structural schematic diagram of a power grid key section searching device provided by an embodiment of the present application;

[0069] Figure 14 A structural schematic diagram of a computer readable storage medium provided by an embodiment of the present application. DETAILED DESCRIPTION

[0070] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0071] In some embodiments, as shown in Figure 1 A flowchart of a power grid key section searching method provided by an embodiment of the present application is shown in the figure, which specifically includes the following steps:

[0072] Step 101: Obtain a first power grid network topology graph, extract and delete a hanging node in the first power grid network topology graph and a line connected to the hanging node, and obtain a second power grid network topology graph, wherein the hanging node is a node with a node degree of 1.

[0073] Specifically, as shown in Figure 2 , it is a topology structure diagram of an IEEE39 node system. The IEEE39 node system is taken as an example for illustration. The system includes 39 nodes and 46 branches in total. The rated capacity of all AC lines is set to 600 MW, and the rated capacity of the transformer is set to 1000 MW.

[0074] The hanging node in Figure 2 and the line connected to the hanging node are extracted, wherein the hanging node is a node with a node degree of 1. In this embodiment, the extracted hanging nodes are nodes 19, 20, 28, 30, 31, 33, 34, 35, 36 and 37 in Figure 2 The extracted hanging nodes and the lines connected to the hanging nodes are deleted, and a second power grid network topology graph of the IEEE39 node system as shown in Figure 3 is obtained.

[0075] It should be noted that node degree refers to the number of lines connected to that node in the network topology diagram. A node degree of one means that there is only one line connected to that node in the network topology diagram.

[0076] Step 102: Search for cut points in the second power grid network topology graph and divide the second power grid network topology graph into several subgraphs through the cut points. The cut points are nodes that, when deleted, would cause the second power grid network topology graph to become unconnected.

[0077] Specifically, in this embodiment, in Figure 3 Search for cut vertices in the network, where a cut vertices are nodes whose deletion would render the second power grid network topology unconnectable. Figure 3 The cut vertex found in the search is node 16. The cut vertex is obtained through node 16. Figure 3 The second power grid network topology diagram is divided into the following: Figure 4 The subgraphs shown in (a) and (b) are shown in the middle.

[0078] Step 103: Obtain the heavily loaded lines in the second power grid network topology diagram, determine the subgraph where the heavily loaded lines are located, and identify the heavily loaded lines as lines whose load rate exceeds a preset threshold.

[0079] Specifically, in this embodiment, lines with a load rate exceeding 50% are identified as heavily loaded lines. After deleting lines connecting suspension nodes, Figure 3 The network topology diagram shown contains 10 heavy-load lines, namely lines 3, 9, 10, 16, 17, 18, 23, 27, 29 and 34.

[0080] To determine which subgraph each heavy-load line belongs to, in this implementation, heavy-load lines 3, 9, 10, 16, 17, 18, and 34 belong to... Figure 4 In the subgraph shown in (a), heavy-load lines 23, 27, and 29 belong to... Figure 4 (b) shows the subgraph.

[0081] Step 104: Using the heavy-load line as the root node, construct a critical section search tree in the subgraph by searching the first shortest path, traverse the critical section search tree, and obtain the critical section of the power grid.

[0082] Specifically, in this embodiment, the process of constructing a critical section search tree and obtaining the critical section of the power grid is illustrated using heavy-load line 17 as an example.

[0083] The shortest path between node 10 and node 13 is searched after disconnecting the heavy load line 17, and the shortest path 10-11-6-5-4-14-13 is obtained. In the shortest path 10-11-6-5-4-14-13, the power flow directions of lines 7, 9, 12 and 16 are the same as the positive direction of the path of the heavy load line 17. The line 7, 9, 12 and 16 are taken as the first level leaf nodes of the key section search tree with the heavy load line 17 as the root node. Then the shortest side path of the line 7 is searched, and the shortest side path 11-12-13 is obtained. The line 35 is the same as the positive direction of the path, and is taken as the second level leaf node of the key section search tree. The remaining nodes are the same. The key section search tree with the line 17 as the root node is finally obtained as shown in Table 1. Figure 5

[0084] According to the construction of the heavy load line 17, the key section search trees of all the heavy load lines are constructed.

[0085] In one embodiment, the key sections of the power grid are obtained by traversing the key section search tree, including:

[0086] Starting from the root node of the key section search tree, a path is followed to the end, and then the last leaf node of the path is returned to the previous leaf node;

[0087] If there is no other leaf node at the previous leaf node except the last leaf node of the path, the process is repeated recursively;

[0088] If there is another leaf node at the previous leaf node except the last leaf node of the path, the other leaf node at the previous leaf node is traversed;

[0089] The process is repeated recursively until all nodes are traversed, and each branch of the key section search tree is obtained, each branch being a group of key sections.

[0090] Preferably, in this embodiment, the key section search tree is traversed by depth-first search.

[0091] Specifically, in this embodiment, the key section search tree is traversed by depth-first search. Figure 5 There are 12 branches, corresponding to 12 groups of key sections. The key sections with the heavy load line 17 as the root node are finally obtained as shown in Table 1. All the key sections with the property of cut set in the power grid are obtained by searching all the branches in all the key section search trees.

[0092] Table 1 Key sections with the heavy load line 17 as the root node

[0093] Serial number Key section Serial number Key section Serial number Key section 1 17,7,35,10,13 2 17,7,35,5,6,31 3 17,9,11,35 4 17,7,35,10,11 5 17,7,35,3,31 6 17,9,13,35 7 17,7,35,5,20 8 17,7,35,3,30 9 17,12,35 10 17,7,35,5,6,30 11 17,7,35,3,25,20 12 17,16

[0094] ​In the embodiment, the power grid network topology is contracted by deleting the hanging nodes in the power grid network topology, and the contracted power grid network topology is divided into multiple subgraphs by cut points, thereby reducing the calculation amount when constructing a key section search tree.

[0095] The line with a higher load rate in the power grid network topology is taken as a search starting point, the shortest path is obtained by searching the shortest lateral path, the key section search tree is constructed, the key section with the cut set property of the power grid is obtained through the key section search tree, and the key section search tree is simple to construct.

[0096] The power grid key section search method disclosed in the embodiment has the characteristics of simplicity, high efficiency, parallelism and the like, and indirectly searches the power grid key section, can balance the accuracy and search efficiency of the search result, and can obtain the key section with the cut set property.

[0097] In some embodiments, as shown in Figure 6 The method comprises:

[0098] In step 601, it is determined whether the subgraph in which the heavy load line is located is deleted, and the first head node and the first end node of the heavy load line are recorded.

[0099] In step 602, the first shortest path between the first head node and the first end node is obtained, and all first lines in the first shortest path are extracted in the direction from the first head node to the first end node.

[0100] In step 603, the first level leaf node of the root node is obtained according to the positive direction of the first line and the power flow direction of the first line, the newly added leaf node is sequentially traversed from the first level leaf node, the leaf node is extended by searching the shortest lateral path of the leaf node, and the positive direction of the first line is the order in which the first line node appears.

[0101] In some embodiments, the first level leaf node of the root node is obtained according to the positive direction of the first line and the power flow direction of the first line, and the method comprises:

[0102] It is determined whether the positive direction of the first line is consistent with the power flow direction of the first line.

[0103] If they are consistent, the first line is taken as the first level leaf node of the root node.

[0104] In some embodiments, the extending the leaf node according to the connectivity result comprises:

[0105] deleting the first line corresponding to the leaf node in the subgraph, detecting connectivity of the subgraph, and obtaining a connectivity result of the subgraph;

[0106] extending the leaf node according to the connectivity result.

[0107] In some embodiments, the extending the leaf node according to the connectivity result comprises:

[0108] if the subgraph is not connected, stopping the extending of the leaf node;

[0109] if the subgraph is connected, searching for a shortest side path of the first line corresponding to the leaf node, judging whether a power flow direction of a second line in the shortest side path is consistent with a positive direction of the second line, and if so, taking the second line as a next level leaf node of the leaf node, wherein the positive direction of the second line is an order in which nodes of the second line appear.

[0110] Step 604: sequentially traversing all the overload lines to obtain the key section search tree of the power grid.

[0111] Specifically, in this embodiment, one of the overload lines l is taken as a root node for illustration, and the first end node of the overload line l is denoted as v s , and the end node is denoted as v t . The overload line l is deleted in a subgraph in which the overload line l is located, and the depth of the tree is denoted as k = 1.

[0112] The shortest path between the first end node v s and the end node v t is calculated, and the shortest path is denoted as {v s v1v2,...,v i v i+ 1v i+2 ,...,v t}. The line in the shortest path {v s v1v2,...,v t v s v i ,...,v i+1} is extracted in the direction from the first end node v i+2 to the end node v t , and the line is denoted as {v s v1,v1v2,...,v i v i+1,v i+1 v i+2 ,...}. The positive direction of the line is determined by the order in which each node appears in the line.

[0113] It should be noted that, in this embodiment, the first segment v is obtained. s and end node v t The shortest path between them can be achieved using existing technologies, and is not limited in this application. Preferably, in this embodiment, the first node v is calculated using Dijkstra's algorithm. s and end node v t The shortest path between them.

[0114] Judge each line v i v i+1 Does the current flow direction align with the positive direction v? i →v i+1 If they match, then line v will be... i v i+1 It serves as a leaf node at level k=2.

[0115] like Figure 7 The diagram shown illustrates how a first-level leaf node is constructed from a power grid topology diagram using a heavily loaded line l as the root node, according to an embodiment of the present invention. The arrows on the sides indicate the power flow direction of the lines. The heavily loaded line l is deleted, and the first node v of the heavily loaded line l is searched. s and end node v t The shortest path between, assuming the shortest path found is {v s v1v2v3v4v t}, which contains {v s v1,v1v2,v2v3,v3v4,v4v t There are 5 lines in total. Determine the relationship between the power flow direction of each line and the positive direction of each line. Among them, the power flow direction of the 3 lines (v1v2), (v2v3), and (v3v4) is the same as its positive direction. These 3 lines are regarded as the first-level leaf nodes.

[0116] Next, in the subgraph where the overloaded line l is located, delete the three lines (v1v2), (v2v3), and (v3v4) in sequence. After deleting each line, determine the connectivity of the subgraph and obtain the connectivity result of the subgraph. If the subgraph is not connected, stop extending the line to the next level leaf node. If the subgraph is connected, search for the shortest side path of the first line corresponding to the leaf node. Determine if the power flow direction of the second line in the shortest side path is consistent with the direction of the second line. Then, take the second line as the next level leaf node of the leaf node. The positive direction of the second line is the order in which the second line nodes appear.

[0117] Specifically, in the embodiment, the line (v1v2) is preferentially analyzed Figure 7 , the line (v1v2) is deleted from the subgraph in which the heavy load line l is located, the subgraph in which the heavy load line l is located is kept connected, the shortest side path of the line (v1v2) is searched as {v1v5v6v3}, as shown in Figure 8 , wherein the power flow directions of the three lines (v1v5), (v5v6), and (v6v3) are consistent with the positive directions of the paths thereof, and the three lines (v1v5), (v5v6), and (v6v3) are taken as the next level leaf nodes of the line (v1v2). The next level nodes of the lines (v2v3) and (v3v4) and the next level nodes thereof are extended through the above method, and finally the key section search tree constructed is as shown in Figure 9 .

[0118] In some embodiments, the searching of the shortest side path of the first line corresponding to the leaf node comprises:

[0119] An upstream contact node is set at an upstream node set of the first shortest path, and a downstream contact node is set at a downstream node set;

[0120] In some embodiments, the second head node and the nodes before the second head node of the first line in the first shortest path constitute the upstream node set, and the second tail node and the nodes after the second tail node of the first line in the first shortest path constitute the downstream node set.

[0121] All nodes in the upstream node set are connected with the upstream contact node, all nodes in the downstream node set are connected with the downstream contact node, and a second shortest path between the upstream contact node and the downstream contact node is searched;

[0122] The second head node of the first line, the second tail node of the first line, the upstream contact node, and the downstream contact node are deleted in the second shortest path, and the path composed of the remaining nodes is the shortest side path of the first line.

[0123] Specifically, in the embodiment, the first line l n is taken as an example for description, the head node of l n is denoted as v m , the tail node is denoted as v n , the shortest path search result is {v s v1,...,v m v n ,...,v t}, wherein the edge (v m v n ) is the line l n , and the upstream contact node and the downstream contact node are set according to v m and vn At the position in the shortest path, divide {v s v1,...,v m} into an upstream node set, divide {v n ,...,v t} into a downstream node set, that is, directly disconnect the path {v s v1,...,v m v n ,...,v t} from the edge (v m v n ), and the nodes in the former half as the upstream node set and the nodes in the latter half as the downstream node set.

[0124] Construct an upstream liaison node s and a downstream liaison node t, connect all nodes in the upstream node set with the node s and all nodes in the downstream node set with the node t, and set the weight of all edges as a minimum value ε>0. The setting of the two liaison nodes can convert the shortest side path search problem into a shortest path search problem between nodes. Search the shortest path between the node s and the node t. In the shortest path search, since the weight of all edges connected with the node s and the node t is ε, the shortest path contains the shortest side path of the node s, the node t and the line l n . After deleting the node v s , the node v t , the node s and the node t in the shortest path, the shortest side path of the line l n .

[0125] It should be noted that in the embodiment, the search of the shortest path can be realized by the prior art. Preferably, in the embodiment, the shortest path is obtained by a depth-first topological search method.

[0126] Taking the shortest side path search in the line l Figure 10 as an example, the shortest path of the root node l is {v s v1v2v3v4v t}, the upstream node set is {v s ,v1} and the downstream node set is {v2,v3,v4,v t}. Connect the nodes in the upstream node set with the node s and the nodes in the downstream node set with the node t, search the second shortest path between the node v s and the node v t , which is {v s sv1v5v6v3tv t}. After deleting the node v s , the node v t , the node s and the node t, the shortest side path is {v1v5v6v3}.

[0127] In some embodiments, if a third line connecting the first node and the second node is disconnected, a path connecting the first node and the second node is stored, the path is a bypass path of the third line.

[0128] Specifically, as shown in Figure 11 Assuming that the source node is node 6 and the sink node is node 7, the original shortest path 6-1-2-3-7 connects node 6 and node 7. When line 1-2 is disconnected, there is a path that does not pass through path 6-1-4-5-3-7 to connect node 6 and node 7, wherein path 1-4-5-3 is a bypass path of line 1-2.

[0129] It should be noted that the bypass path can be a path composed of one line or multiple lines.

[0130] In some embodiments, as shown in Figure 12 FIG. 1 is a structural schematic diagram of a power grid key section search device provided by an embodiment of the present application, which comprises

[0131] The acquisition module 1201 is configured to acquire a first power grid network topology graph, extract and delete a hanging node and a line connected to the hanging node in the first power grid network topology graph, and obtain a second power grid network topology graph, wherein the hanging node is a node with a degree of one.

[0132] The division module 1202 is configured to search for cut points in the second power grid network topology graph, divide the second power grid network topology graph into a plurality of subgraphs through the cut points, and the cut point is a node that causes the second power grid network topology graph to be disconnected after being deleted.

[0133] The judgment module 1203 is configured to acquire an overload line in the second power grid network topology graph, and judge the subgraph in which the overload line is located, wherein the overload line is a line with a load rate exceeding a preset threshold.

[0134] The search module 1204 is configured to take the overload line as a root node, construct a key section search tree in the subgraph by searching for a first shortest path, traverse the key section search tree, and acquire the key section of the power grid.

[0135] For other details of the implementation of each module in the above power grid key section search device to achieve the above technical solutions, refer to the description of the above provided power grid key section search method, which will not be repeated here.

[0136] In some embodiments, as shown in Figure 13As shown, the embodiment of the present application further provides a structural schematic diagram of a power grid key section searching device, which comprises a memory 1301 and a processor 1302, the memory 1301 stores a computer program, and the computer program is executed by the processor 1302, so that the processor 1301 performs the following steps:

[0137] Obtaining a first power grid network topology graph, extracting and deleting a hanging node and a line connected with the hanging node in the first power grid network topology graph to obtain a second power grid network topology graph, the hanging node being a node with a degree of one;

[0138] Searching for a cut point in the second power grid network topology graph, dividing the second power grid network topology graph into a plurality of subgraphs through the cut point, the cut point being a node that causes the second power grid network topology graph to be unable to be connected after being deleted;

[0139] Obtaining an overload line in the second power grid network topology graph, judging a subgraph where the overload line is located, the overload line being a line with a load rate exceeding a preset threshold;

[0140] Taking the overload line as a root node, constructing a key section searching tree in the subgraph through searching for a first shortest path, traversing the key section searching tree, and obtaining the key section of the power grid.

[0141] For other details of the processor 1301 in the power grid key section searching device for implementing the above technical solutions, reference can be made to the description of the power grid key section searching method provided above, which will not be described here.

[0142] The processor 1301 can also be referred to as a CPU (Central Processing Unit, central processing unit), and the processor 1301 can be an integrated circuit chip with a signal processing capability; the processor 1301 can also be a general-purpose processor, a DSP (Digital Signal Process, digital signal processor), an ASIC (Application Specific Integrated Circuit, application specific integrated circuit), an FPGA (Field Programmable Gata Array, field programmable gate array) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, and the general-purpose processor can be a microprocessor or the processor 1301 can also be any conventional processor.

[0143] In some embodiments, as Figure 14As shown, the embodiment of the present application further provides a structural diagram of a computer readable storage medium, and the storage medium stores a readable computer program 1401; wherein the computer program 1401 can be stored in the above storage medium in the form of a software product, and includes a plurality of instructions to make a computer device (which can be a personal computer, a service machine, or a network device, etc.) or a processor execute the following steps:

[0144] Obtaining a first power grid network topology graph, extracting and deleting a hanging node and a line connected with the hanging node in the first power grid network topology graph to obtain a second power grid network topology graph, the hanging node being a node with a degree of one;

[0145] Searching for a cut point in the second power grid network topology graph, dividing the second power grid network topology graph into a plurality of subgraphs through the cut point, the cut point being a node that causes the second power grid network topology graph to be unable to be connected after being deleted;

[0146] Obtaining an overload line in the second power grid network topology graph, judging a subgraph in which the overload line is located, the overload line being a line with a load rate exceeding a preset threshold;

[0147] Taking the overload line as a root node, constructing a key section search tree in the subgraph through searching for a first shortest path, traversing the key section search tree, and obtaining the key section of the power grid.

[0148] The storage medium includes: a U disk, a mobile hard disk, a magnetic or optical disk, a ROM (Read-Only Memory), a RAM (Random Access Memory), and various storage code media, or a computer, a service machine, a mobile phone, a tablet, and other terminal devices.

[0149] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The program can be stored in a non-volatile computer readable storage medium, and when the program is executed, the processes of the above-mentioned embodiment methods can be included. Any reference to memory, storage, database, or other medium used in the embodiments provided in the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0150] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the present application.

[0151] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for searching a critical section of an electric power grid, characterized in that, The method comprises: obtaining a first power grid network topology graph, extracting and deleting a hanging node in the first power grid network topology graph and a line connected with the hanging node, obtaining a second power grid network topology graph, the hanging node being a node with a degree of 1; searching for a cut point in the second power grid network topology graph, dividing the second power grid network topology graph into a plurality of subgraphs through the cut point, the cut point being a node that causes the second power grid network topology graph to be unable to be connected after being deleted; obtaining an overload line in the second power grid network topology graph, judging a subgraph in which the overload line is located, the overload line being a line with a load rate exceeding a preset threshold; taking the overload line as a root node, constructing a key section search tree in the subgraph through searching for a first shortest path, traversing the key section search tree, and obtaining the key section of the power grid; wherein, constructing a key section search tree in the subgraph through searching for a first shortest path comprises: judging the subgraph in which the overload line is located, deleting the overload line in the subgraph, and recording a first head node and a first tail node of the overload line; obtaining a first shortest path between the first head node and the first tail node, extracting all first lines in the first shortest path in the direction from the first head node to the first tail node; obtaining a first level leaf node of the root node according to a positive direction of the first line and a power flow direction of the first line, starting from the first level leaf node, sequentially traversing newly added leaf nodes, extending the leaf nodes by searching for a shortest side path of the leaf nodes, wherein the positive direction of the first line is the order in which the first line nodes appear; sequentially traversing all the overload lines to obtain the key section search tree of the power grid.

2. The power grid critical section search method according to claim 1, characterized by, The method comprises: judging whether the positive direction of the first line is consistent with the power flow direction of the first line; if consistent, taking the first line as a first level leaf node of the root node.

3. The method of claim 1, wherein, The method comprises: deleting the first line corresponding to the leaf node in the subgraph, detecting the connectivity of the subgraph, and obtaining a connectivity result of the subgraph; extending the leaf node according to the connectivity result.

4. The power grid critical section search method according to claim 3, characterized by, The method comprises: if the subgraph is not connected, stopping the extension of the leaf node; if the subgraph is connected, searching for a shortest side path of the first line corresponding to the leaf node, judging whether the power flow direction of a second line in the shortest side path is consistent with the positive direction of the second line, if consistent, taking the second line as a next level leaf node of the leaf node, wherein the positive direction of the second line is the order in which the second line nodes appear.

5. The power grid critical section search method according to claim 4, characterized by, The searching the shortest side path of the leaf node corresponding to the first line comprises: setting an upstream contact node for a set of upstream nodes of the first shortest path and setting a downstream contact node for a set of downstream nodes; connecting all nodes in the set of upstream nodes to the upstream contact node and connecting all nodes in the set of downstream nodes to the downstream contact node, and searching a second shortest path between the upstream contact node and the downstream contact node; deleting the first head node and the first tail node of the overloaded line, the upstream contact node and the downstream contact node in the second shortest path, and forming a path with the remaining nodes as the shortest side path of the first line.

6. The power grid critical section search method according to any one of claims 4 or 5, characterized in that, If a third line connecting a first node and a second node is disconnected, and there is a path connecting the first node and the second node, the path is a side path of the third line.

7. The method of claim 5, wherein, The second head node and the nodes before the second head node of the first line in the first shortest path form the set of upstream nodes, and the second tail node and the nodes after the second tail node of the first line in the first shortest path form the set of downstream nodes.

8. The method of claim 1, wherein, The searching the key section of the power grid comprises: starting from a root node of the key section search tree, walking along a path to the end, and then backtracking from a leaf node at the end of the path to a previous leaf node; if there is no other leaf node at the previous leaf node except the leaf node at the end of the path, backtracking further up; if there are other leaf nodes at the previous leaf node except the leaf node at the end of the path, traversing the other leaf nodes from the previous leaf node; continuously repeating the process recursively until all nodes are traversed to obtain each branch of the key section search tree, and each branch is a set of cut-set type key sections.

9. A power grid critical section search apparatus characterized by comprising: The device comprises: an acquisition module configured to acquire a first power grid network topology diagram, extract and delete a hanging node and a line connected to the hanging node in the first power grid network topology diagram, and obtain a second power grid network topology diagram, the hanging node being a node with a degree of one; a division module configured to search for cut points in the second power grid network topology diagram, divide the second power grid network topology diagram into a plurality of sub-diagrams through the cut points, and the cut points being nodes that cause the second power grid network topology diagram to be disconnected after being deleted; a judgment module configured to acquire an overloaded line in the second power grid network topology diagram, judge a sub-diagram in which the overloaded line is located, and the overloaded line being a line with a load rate exceeding a preset threshold; a search module configured to take the overloaded line as a root node, construct a key section search tree by searching for a first shortest path in the sub-diagram, traverse the key section search tree, and acquire the key section of the power grid; the search module is further configured to judge the sub-diagram in which the overloaded line is located, delete the overloaded line in the sub-diagram, and record a first head node and a first tail node of the overloaded line. obtaining a first shortest path between the first head node and the first end node, and extracting all first lines in the first shortest path in the direction from the first head node to the first end node; obtaining a first level leaf node of the root node according to the positive direction of the first line and the power flow direction of the first line, and extending the leaf node by searching the shortest side path of the leaf node, starting from the first level leaf node and sequentially traversing the newly added leaf node; wherein the positive direction of the first line is the order in which the first line node appears; sequentially traversing all the overloaded lines to obtain the key section search tree of the power grid.

10. A power grid key section search device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor to make the processor execute the steps of the method according to any one of claims 1 to 8.

11. A computer readable storage medium, storing a computer program, wherein the computer program is executed by a processor to make the processor execute the steps of the method according to any one of claims 1 to 8.

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