A power distribution network loop and island rapid detection method

Abstract

This invention discloses a rapid detection method for loops and islands in a distribution network, comprising: selecting the distribution network for which loop and island information needs to be detected; determining the correspondence between branches and their two endpoints within the distribution network; extracting a branch within the distribution network and placing it into a corresponding island based on the different association relationships between the branch and its two endpoints, recording the island topology information within the distribution network at this time; determining whether there is a new loop within the current island based on the branch algebraic iteration inequality, obtaining and recording the loop branch information of the current island; traversing all branches within the distribution network and obtaining the loop and island information of the distribution network using the above method. This invention rapidly detects loop and island information in a distribution network through a branch number iteration method, without involving frequent topology calculations, thus greatly saving computation time and having significant implications for power grid analysis.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system automation, in particular to a method for detecting loops and islands of a power distribution network. BACKGROUND

[0002] The power system is an important infrastructure of modern society, and its safe, reliable and high-quality operation is an important guarantee for people's normal life. With the rapid construction and in-depth development of the power distribution network, the power distribution network structure is becoming increasingly complex, the power grid equipment is showing a new trend of rapid growth, rapid change and diversification, and the asset management level of the power grid equipment is continuously improving, which also puts forward higher requirements for the loop detection business function of the power distribution network.

[0003] Due to the large number of lines in the power distribution network, the enumeration method is used to enumerate and verify the line combinations that may form loops, and due to the frequent topological calculation involved in this method, the calculation time is greatly lengthened. Considering the efficiency of loop set solving, it is urgent to find a simple method to shorten the calculation time at the present stage, so as to quickly detect the loops and islands of the power distribution network. SUMMARY

[0004] The present application proposes a method for quickly detecting loops and islands of a power distribution network, which aims to improve the calculation efficiency and quickly detect the loops and islands of the power distribution network.

[0005] The technical scheme of the present application is as follows:

[0006] A method for quickly detecting loops and islands of a power distribution network, comprising the following steps:

[0007] S1: selecting a power distribution network that needs to detect loop and island information, determining the corresponding information of the branch and its two end nodes in the power distribution network, setting the island number N, branch number X i , node number I i , loop number Y i to 0, and i is the island label;

[0008] S2: taking out a branch in the power distribution network, putting the branch into the corresponding island according to the different association relationship of the branch and its two side nodes, recording the island topology structure information of the power distribution network at this time;

[0009] S3: judging whether there is a new loop in the current island according to the branch algebraic iteration inequality, if yes, executing step S4, otherwise, turning to step S5;

[0010] S4: obtaining the loop branch information of the current island according to the island topology structure information and recording;

[0011] S5: repeating steps S2-S4 until all branches in the power distribution network are traversed, and obtaining the loop and island information of the power distribution network.

[0012] Further, the step S2 specifically includes the following cases:

[0013] a. If the branch is not associated with any node in the existing islands, the branch is put into a new island alone, the number of islands N=N+1, the number of branches X i =X i +1 in the new island, the number of nodes I i =I i +2 in the new island;

[0014] b. If the branch is only associated with a node in one of the existing islands, the branch is put into the corresponding island associated node, the number of branches X i =X i +1 in the current island, the number of nodes I i =I i +1 in the current island;

[0015] c. If the branch is associated with two nodes in one of the existing islands, the branch is put into the corresponding island associated node, the number of branches X i =X i +1 in the current island;

[0016] d. If the branch is associated with nodes in two of the existing islands, i.e. the two nodes associated with the branch belong to two different islands, the two islands are merged, then the branch is put into the corresponding associated node, and the empty island is deleted, the number of islands N=N-1, the number of branches, nodes and loops in the current island are counted.

[0017] Further, the branch algebraic iteration inequality in step S3 is:

[0018] X i >I i +Y i -1

[0019] If the inequality holds, it is determined that a new loop appears in the island, the number of loops Y i =Y i +1 in the current island, otherwise it is determined that there is no new loop in the island.

[0020] Further, the step S4 specifically includes:

[0021] S4-1: Extract the topological structure information of the current island, and remove the known loop branches on the topological graph of the island;

[0022] S4-2: Remove the nodes associated with only one branch and the corresponding branch;

[0023] S4-3: repeat step S4-2 for the remaining current island topology until all the nodes left in the island are associated with two branches, at which time the remaining branches are loop branch information, and the loop information is recorded.

[0024] Compared with the prior art, the present application has the following beneficial effects: the loop and island information of the power distribution network is quickly detected by the branch number iteration method, frequent topology calculation is not involved, and therefore the calculation time is greatly saved, which is of great significance for power grid analysis. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a flowchart of the present application;

[0026] Figure 2 is a schematic diagram of steps 1 to 5 of embodiment two of the present application;

[0027] Figure 3 is a schematic diagram of steps 6 to 9 of embodiment two of the present application;

[0028] Figure 4 is a schematic diagram of steps 10 to 11 of embodiment two of the present application. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings:

[0030] Embodiment one:

[0031] As Figure 1 , a fast detection method for loop and island of a power distribution network, comprising the following steps:

[0032] S1: selecting a power distribution network for which loop and island information needs to be detected, determining the branch and its two end node corresponding information in the power distribution network, and the key equipment information corresponding to the branch. Assigning initial values of island number N, branch number X i , node number I i , loop number Y i to 0, and i is the island index.

[0033] S2: taking out a branch in the power distribution network, and placing the branch in the corresponding island according to the different association relationship of the branch and its two side nodes, the island is recorded as the current island, and the island topology information in the power distribution network at this time is recorded.

[0034] Specifically, the following cases are included:

[0035] a. If the branch has no association with all the nodes in the existing island, the branch is placed in a new island alone, the island number N = N + 1, the branch number X i of the new island = X i + 1, the node number I i of the new island = Ii +2;

[0036] b. If the branch is associated with only one node in one of the existing islands, the branch is placed in the corresponding island associated node, and the number of branches X of the current island i = X i +1, the number of nodes I of the current island i = I i +1;

[0037] c. If the branch is associated with two nodes in one of the existing islands, the branch is placed in the corresponding island associated node, and the number of branches X of the current island i = X i +1;

[0038] d. If the branch is associated with nodes in two of the existing islands, that is, the two nodes associated with the branch belong to two different islands, the two islands are merged, then the branch is placed in the corresponding associated node, and the empty island is deleted, the number of islands N = N-1, and the number of branches, nodes and loops of the current island are counted (the number of branches of the current island is the sum of the number of branches of the two islands before merging plus 1, and the number of nodes and loops of the current island are obtained by summing the number of nodes and loops of the two islands before merging).

[0039] S3: Determine whether there is a new loop in the current island according to the branch algebraic iterative inequality, if yes, execute step S4, otherwise go to step S5.

[0040] The branch algebraic iterative inequality is:

[0041] X i > I i + Y i -1

[0042] If the inequality holds, it is determined that a new loop appears in the island, and the number of loops Y of the current island i = Y i +1, otherwise it is determined that there is no new loop in the island.

[0043] S4: Obtain the loop branch information of the current island according to the island topology structure information and record it.

[0044] Specifically, the following steps are included:

[0045] S4-1: Extract the topology structure information of the current island, and remove the known loop branches on the topology graph of the island;

[0046] S4-2: Remove the nodes associated with only one branch and the corresponding branch;

[0047] S4-3: repeat step S4-2 for the remaining current island topology until all the nodes left in the island are associated with two branches, at which time the remaining branches are loop branch information, and the loop information is recorded.

[0048] S5: repeat steps S2-S4 until all the branches in the power distribution network are traversed, and loop and island information of the power distribution network is obtained.

[0049] The method quickly detects loop and island information of the power distribution network through branch number iteration, and finally determines: 1) whether a loop exists in a feeder; 2) whether an island exists in the feeder, and identifies devices in the island; 3) if a loop exists, key branch information of the loop is given; and 4) a number of simple loops (without considering ring-in-ring) is given.

[0050] Embodiment two:

[0051] As Figures 2 to 4 , the method is used for quickly detecting loop and island information of the power distribution network, and the specific steps are as follows:

[0052] Step one: the branch 1-2 is not associated with all the nodes in the existing island, and is placed in a new island 1 alone, at which time the island number N=1, the branch number X1 of the new island 1 is 1, the node number I1 is 2, the loop number Y1 is 0, and it is determined that the branch number iteration inequality is not established.

[0053] Step two: the branch 2-3 is associated with the node 2 in the island 1, and is placed on the corresponding island associated node (the node 2 in the island 1), at which time the island number N=1, the branch number X1 of the current island is 2, the node number I1 is 3, the loop number Y1 is 0, and it is determined that the branch number iteration inequality is not established.

[0054] Step three: the branch 5-6 is not associated with all the nodes in the existing island, and is placed in a new island 2 alone, at which time the island number N=2, the branch number X2 of the new island 2 is 1, the node number I2 is 2, the loop number Y2 is 0, and it is determined that the branch number iteration inequality is not established.

[0055] Step four: the branch 3-4 is associated with the node 3 in the island 1, and is placed on the corresponding island associated node (the node 3 in the island 1), at which time the island number N=2, the branch number X1 of the island 1 is 3, the node number I1 is 4, the loop number Y1 is 0, and it is determined that the branch number iteration inequality is not established.

[0056] Step five: the branch 1-3 is associated with the nodes 1 and 3 in the island 1, and is placed on the corresponding island associated node (the nodes 1 and 3 in the island 1); at which time the island number N=2, the branch number X1 of the island 1 is 4, the node number I1 is 4, the loop number Y1 is 0, and it is determined that the branch number iteration inequality is established, which indicates that a new loop appears in the island, and the loop number Y1 is 1.

[0057] Extract the topology information of the current island. Remove all nodes and their corresponding branches (node ​​4, branch 3-4) on the topology graph of island 1 that are associated with only one branch. Repeat this step for the remaining island topology until all remaining nodes are associated with two branches. The remaining branches are the loop branches and are recorded. Loop 1: 1-2, 2-3, 3-1.

[0058] Step 6: Since branches 21-22 are not related to any nodes in the existing island, they are placed in the new island 3. At this time, the number of islands N = 3, the number of branches X3 = 1, the number of nodes I3 = 2, and the number of loops Y3 = 0. It is determined that the branch algebra iteration inequality does not hold.

[0059] Step 7: If branch 5-7 is related to node 5 in island 2, then place the branch on the corresponding island-related node (node ​​5 in island 2). At this time, the number of islands N = 3, the number of branches in island 2 X2 = 2, the number of nodes I2 = 3, and the number of loops Y2 = 0. It is determined that the branch algebra iteration inequality does not hold.

[0060] Step 8: If branch 6-8 is related to node 6 in island 2, then place the branch on the corresponding island-related node (node ​​6 in island 2). At this time, the number of islands N = 3, the number of branches in island 2 X2 = 3, the number of nodes I2 = 4, and the number of loops Y2 = 0. It is determined that the branch algebra iteration inequality does not hold.

[0061] Step 9: If branch 8-9 is related to node 8 in island 2, then place the branch on the corresponding island's related node (node ​​8 in island 2). At this time, the number of islands N = 3, the number of branches in island 2 X2 = 4, the number of nodes I2 = 5, and the number of loops Y2 = 0. It is determined that the branch algebra iteration inequality does not hold.

[0062] Step 10: Since branch 4-6 is related to node 4 in island 1 and node 6 in island 2, merge these two islands into island 1. Then, place branch 4-6 onto the corresponding related nodes (nodes 4 and 6 in island 1) and delete empty island 2. At this time, the number of islands N = 2, the number of branches in island 1 X1 = 9, the number of nodes I1 = 9, and the number of loops Y1 = 1. It is determined that the branch algebra iteration inequality does not hold.

[0063] Step 11: If branch 7-8 is related to nodes 7 and 8 in island 1, then place the branch on the corresponding related node (nodes 7 and 8 in island 1). At this time, the number of islands N = 2, the number of branches in island 1 X1 = 10, the number of nodes I1 = 9, and the number of loops Y1 = 1. If the branch algebra iteration inequality holds, it means that a new loop has appeared in the island, and the number of loops in island 1 Y1 = 2.

[0064] Extract the topology information of the current island. Remove loop 1 from the topology graph of island 1, and remove all nodes and their corresponding branches that are associated with only one branch, until all remaining nodes are associated with two branches. The remaining branches are the loop branch information and are recorded. Specifically, first remove node 3 and its corresponding branch 3-4, node 9 and its corresponding branch 8-9, and then remove node 4 and its corresponding branch 4-6 from the remaining island topology. At this point, all remaining nodes are associated with two branches, obtaining the loop branch information and recording it. Loop 2: 5-6, 6-8, 8-7, 7-5.

[0065] Finally, it was found that there are two loops in the distribution network, namely loop 1: 1-2, 2-3, 3-1 and loop 2: 5-6, 6-8, 8-7, 7-5, as well as two islands.

Claims

1. A rapid detection method for distribution network loops and islanding, characterized in that, Includes the following steps: S1: Select the distribution network for which loop and island information needs to be detected, determine the corresponding information of branches and their two-end nodes within the distribution network, and count the number of islands. , number of branches Number of nodes Number of loops Initialize to 0, The island's designation; S2: Take out a branch in the distribution network, and put the branch into the corresponding island according to the different association relationships between the branch and the nodes on both sides. This island is called the current island. Record the island topology information in the distribution network at this time. Step S2 specifically includes the following situations: a. If the branch is not associated with any node on the existing island, then place the branch on a new island, and the number of islands is [number missing]. The number of branches on the new island The number of nodes on the new island ; b. If the branch is associated with only one node within one of the existing islands, then place the branch on the associated node of the corresponding island, and the number of branches on the current island is [number missing]. The current number of nodes on the island ; c. If the branch is associated with two nodes on one of the existing islands, then place the branch on the associated node on the corresponding island, and the number of branches on the current island is [number missing]. ; d. If the branch is associated with nodes on two existing islands (i.e., the two associated nodes belong to two different islands), then merge these two islands, place the branch onto the corresponding associated node, and delete empty islands. Count the number of branches on the current island. Number of nodes and number of loops; S3: Determine whether there is a new loop in the current island based on the branch algebra iteration inequality. If yes, proceed to step S4; otherwise, go to step S5. The branch algebraic iteration inequality mentioned in step S3 is: ; If the inequality holds, then a new loop has appeared on the island, and the current number of loops on the island is determined. Otherwise, it is determined that there are no new loops within the island; S4: Obtain and record the loop branch information of the current island based on the island topology information; Step S4 specifically includes: S4-1: Extract the topology information of the current island and remove known loop branches on the island's topology map; S4-2: Remove nodes and their corresponding branches that are associated with only one branch; S4-3: Repeat step S4-2 for the remaining current island topology until all remaining nodes in the island are associated with two branches. At this point, the remaining branches are the loop branch information. Record the loop information. S5: Repeat steps S2-S4 until all branches in the distribution network have been traversed, and obtain the loop and island information of the distribution network.

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