A method, device and storage medium for locating power grid faults

Abstract

The present invention relates to the technical field of power distribution networks, and in particular to a power grid fault location method, device and computer storage medium; the power grid fault location method described in the present invention is suitable for locating a fault when a fault occurs inside a tree-structured power grid with direct electrical connection, by introducing a virtual fault point, using it as a dynamic reference point of a current reference direction, and dynamically adjusting the fault current phase, so that the current phase of a fault occurring at any position has a unified mode, which greatly simplifies the complexity of the fault location algorithm and can adapt to a tree-structured power grid of any complexity.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution network, and in particular to a power grid fault locating method, device and computer storage medium. Background Art

[0002] The location of power grid faults depends on the collection of fault information. The collection of fault location information is divided into collection during the fault and collection after the fault. For collection after the fault, because the electrical characteristics of the fault have disappeared, only non-electrical methods can be used. In complex or long-distance power grids, it is time-consuming and laborious to find the fault point. Therefore, it is of great value to collect the current at the time of the fault at the appropriate location as a basis for fault location. Common location algorithms include current mutation method, differential current method, etc. These methods compare the changes in current amplitude and can only be applied to simple power grids with a single power supply. In complex power grids with multiple power supplies, the changes in current amplitude no longer have a significant pattern, and the fault cannot be located based on this. In comparison, the current phase comparison method has more advantages in complex power grid fault location because it compares the combination mode of the current phase related to the fault point, which has a higher fault tolerance than the current amplitude.

[0003] The usual phase comparison algorithm predicts the phase pattern of the relevant fault current according to the fault location and compares it with the actual measured value.

[0004] Please refer to Figure 1 , F is the fault point, T is the measuring point, and the current at all measuring points is positive when it points to the power supply. If T1 and T2 are in anti-phase, T1 and T3 are in anti-phase, and T2 and T3 are in phase, then F1 is faulty; if T1 and T2 are in phase, T1 and T3 are in phase, and T2 and T3 are in phase, then F2 is faulty; if T1 and T2 are in phase, T1 and T3 are in anti-phase, and T2 and T3 are in anti-phase, then F3 is faulty; if T1 and T2 are in phase, T1 and T3 are in anti-phase, and T2 and T3 are in anti-phase, then F4 is faulty.

[0005] For one-way tree fault location, each fault point requires 2 measurement points, there are 4 combinations, and 8 combinations for 2 fault intervals.

[0006] For binary tree fault location, each fault point requires 3 measurement points, with 8 combinations and 32 combinations for 4 fault intervals.

[0007] For ternary tree fault location, each fault point requires 4 measurement points, with 16 combinations, and 80 combinations for 5 fault intervals.

[0008] It can be seen that with the increase in the complexity of power grid topology, the change of operating mode at any time, and the increase in fault types, the phase combination pattern of fault current increases exponentially and the high complexity makes it difficult for the prediction mode to cover all possible situations, or even impossible to predict. Summary of the invention

[0009] Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that the phase comparison algorithm is difficult to predict the phase pattern of the relevant fault current in a complex power grid.

[0010] In order to solve the above technical problems, the present invention provides a power grid fault location method, comprising:

[0011] Adjust the starting polarity of all measuring point currents to point to the root node as positive;

[0012] Insert virtual fault points between adjacent measuring points of the power grid, between measuring points and root nodes, and between measuring points and leaf nodes;

[0013] Find the first group of shortest paths from each leaf node to the root node, and record the order in which the virtual fault points at both ends of each measuring point appear in the first group of shortest paths as the standard polarity of each measuring point;

[0014] For virtual fault points with more than one adjacent measuring point, find the second group of shortest paths from the root node and the leaf node to each virtual fault point, and record the order in which the virtual fault points at both ends of the adjacent measuring points of each virtual fault point appear in the second group of shortest paths as the fault polarity of the adjacent measuring points of each virtual fault point;

[0015] Compare the fault polarity and standard polarity of the adjacent measuring points of each virtual fault point. If they are opposite, adjust the current polarity of the measuring point to the opposite current polarity.

[0016] It is determined whether the maximum phase angle difference between all adjacent measuring points of a virtual fault point with more than one adjacent measuring point exceeds a preset threshold. If not, the fault occurs within the range covered by the virtual fault point to all its adjacent measuring points.

[0017] Preferably, after inserting a virtual fault point between adjacent measuring points, between a measuring point and a root node, or between a measuring point and a leaf node of the power grid, the method further comprises:

[0018] Merge the virtual failure points at the branches.

[0019] Preferably, for more than one virtual fault point adjacent to a measuring point, finding the shortest path from the root node and the leaf node to each virtual fault point, and recording the order in which the virtual fault points at both ends of the adjacent measuring points of each virtual fault point appear in the path before the fault polarity of each adjacent measuring point of the virtual fault point also includes:

[0020] The current amplitude change is used as a criterion to roughly determine the fault range, and the next step of calculation is performed within the fault range.

[0021] Preferably, if the maximum phase angle difference between all adjacent measuring points of more than one virtual fault point exceeds a preset threshold, the fault is between a certain root or leaf and its adjacent measuring point.

[0022] Preferably, if the fault is between a root or leaf and its adjacent measuring point, the current amplitude change is used as a criterion for further positioning.

[0023] Preferably, the algorithm for fault location using current amplitude change as a criterion includes a current mutation method and a current difference method.

[0024] Preferably, the preset threshold is 90°.

[0025] The present invention also provides a power grid fault locating device, comprising:

[0026] The measuring point starting polarity adjustment module is used to adjust the starting polarity of all measuring point currents to point to the root node as positive;

[0027] A virtual fault point insertion module is used to insert a virtual fault point between adjacent measuring points, between a measuring point and a root node, and between a measuring point and a leaf node of the power grid;

[0028] A measuring point standard polarity calculation module is used to find the first group of shortest paths from each leaf node to the root node, and record the order in which the virtual fault points at both ends of each measuring point appear in the first group of shortest paths as the standard polarity of each measuring point;

[0029] A measuring point fault polarity calculation module is used to find a second group of shortest paths from the root node and the leaf node to each virtual fault point for more than one adjacent measuring point, and record the order in which the virtual fault points at both ends of the adjacent measuring points of each virtual fault point appear in the second group of shortest paths as the fault polarity of the adjacent measuring points of each virtual fault point;

[0030] A current polarity adjustment module is used to compare the fault polarity and standard polarity of the adjacent measuring points of each virtual fault point. If they are opposite, the current polarity of the measuring point is adjusted to the opposite current polarity.

[0031] The fault location module is used to determine whether the maximum phase angle difference between all adjacent measuring points of a virtual fault point with more than one adjacent measuring point exceeds a preset threshold. If not, the fault occurs within the range covered by the virtual fault point to all its adjacent measuring points.

[0032] Preferably, the power grid fault locating device is applied to a tree-structured power grid with direct electrical connections.

[0033] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned power grid fault locating method are implemented.

[0034] The above technical solution of the present invention has the following advantages compared with the prior art:

[0035] The present invention is based on the assumption that energy always flows to the fault point. If the fault point is used as the direction, all adjacent currents of the fault point should be in phase. Therefore, assuming a certain point fault, the reference phase of the current of its adjacent measuring points is adjusted to point to this point as positive. If all are in phase, the fault is true, otherwise it is false. The power grid fault locating method described in the present invention is suitable for fault locating when a fault occurs inside a tree-structured power grid with direct electrical connection. By introducing a virtual fault point, it is used as a dynamic reference point of the current reference direction, and the fault current phase is dynamically adjusted, so that the current phase of the fault at any position has a unified mode, which greatly simplifies the complexity of the fault locating algorithm and can adapt to tree-structured power grids of arbitrary complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0037] Figure 1 It is a schematic diagram of a power grid structure;

[0038] Figure 2 It is a flow chart of the implementation of the power grid fault location method of the present invention;

[0039] Figure 3 is a power grid structure diagram provided by an embodiment of the present invention;

[0040] Figure 4 A structural block diagram of a power grid fault locating device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The core of the present invention is to provide a power grid fault location method, device and computer storage medium, which greatly simplifies the complexity of the fault location algorithm.

[0042] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] Please refer to Figure 2, Figure 2 The following is a flowchart of the method for locating a power grid fault provided by the present invention; the specific operation steps are as follows:

[0044] The present invention is based on the assumption that energy always flows toward the fault point. If the fault point is used as the direction, all adjacent currents of the fault point should be in phase. Therefore, assuming a fault at a certain point, the reference phase of the current of the adjacent measuring points is adjusted to point to this point as positive. If all are in phase, the fault is true, otherwise it is false.

[0045] The present invention is applicable to fault location when a fault occurs inside a tree-structured power grid with direct electrical connections; the root node of the tree is usually a bus or a power source, the leaf node is usually a load or a distributed power source, and other nodes include measuring points, branch points, etc. The present invention does not limit the type of any node.

[0046] S201: Adjust the starting polarity of all measuring point currents to point to the root node as positive;

[0047] S202: inserting virtual fault points between adjacent measuring points of the power grid, between a measuring point and a root node, and between a measuring point and a leaf node;

[0048] Since multiple virtual fault points are generated at branch intersections, the virtual fault points at the branches are merged.

[0049] S203: Find a first group of shortest paths from each leaf node to the root node, and record the order in which the virtual fault points at both ends of each measuring point appear in the first group of shortest paths as the standard polarity of each measuring point;

[0050] S204: For virtual fault points with more than one adjacent measuring point, find a second group of shortest paths from the root node and the leaf node to each virtual fault point, and record the order in which the virtual fault points at both ends of the adjacent measuring points of each virtual fault point appear in the second group of shortest paths as the fault polarity of the adjacent measuring points of each virtual fault point;

[0051] Before step S204, the current amplitude change is used as a criterion to roughly determine the fault range, and virtual fault points within the range are preferentially investigated without calculating all virtual fault points, thereby reducing the amount of calculation.

[0052] S205: comparing the fault polarity and standard polarity of the adjacent measuring points of each virtual fault point, and if they are opposite, adjusting the current polarity of the measuring point to the opposite current polarity;

[0053] S206: Determine whether the maximum phase angle difference between all adjacent measuring points of a virtual fault point with more than one adjacent measuring point exceeds a preset threshold. If not, the fault occurs within the range covered by the virtual fault point to all its adjacent measuring points.

[0054] The preset threshold is determined according to the measurement accuracy and network parameters. It can be reduced if the accuracy is high and increased if the accuracy is low. It is an empirical value, generally between 60 and 120. In this embodiment, it is set to 90°. When it does not exceed the preset threshold, the currents at adjacent measuring points are in phase.

[0055] If the maximum phase angle difference between all adjacent measuring points of more than one virtual fault point exceeds the preset threshold, the fault is between a root or leaf and its adjacent measuring point. At this time, other criteria are needed to assist in judgment, such as current amplitude, voltage and temperature. Among them, the algorithms that use current amplitude changes as a criterion for fault location include current mutation method and differential current method.

[0056] The power grid fault location method described in the present invention is suitable for fault location when a fault occurs inside a tree-structured power grid with direct electrical connections. By introducing a virtual fault point and using it as a dynamic reference point for the current reference direction, the fault current phase is dynamically adjusted so that the current phase of a fault occurring at any position has a unified pattern, which greatly simplifies the complexity of the fault location algorithm and can adapt to tree-structured power grids of arbitrary complexity.

[0057] Based on the above embodiments, this embodiment is based on Figure 3 Taking the power grid structure as an example, the method of the present invention is further described:

[0058] Virtual fault points are inserted between all measuring points and between measuring points and root leaves. The virtual fault points at the branches are merged. The final virtual fault points are V1, V2, V3, V4, and V5.

[0059] Find the shortest path from all leaves to the root:

[0060] The shortest path from D3 to D1 is: D3V4T3V1T1V2D1

[0061] The shortest path from D2 to D1 is: D2V5T4V3T2V1T1V2D1

[0062] The order in which the virtual fault points at both ends of each measuring point appear in the path is recorded as the standard polarity of the measuring point:

[0063] The standard polarity of T1 is: V1V2

[0064] The standard polarity of T2 is: V3V1

[0065] The standard polarity of T3 is: V4V1

[0066] The standard polarity of T4 is: V5V3

[0067] For each virtual fault point with more than one adjacent measurement point, find the shortest path from all roots and leaves to each virtual fault point:

[0068] In this figure, V2V4V5 has only one adjacent measuring point and does not need to be calculated.

[0069] For V1:

[0070] The shortest path from D1 to V1 is: D1V2T1V1

[0071] The shortest path from D2 to V1 is: D2V5T4V3T2V1

[0072] The shortest path from D3 to V1 is: D3V4T3V1

[0073] For V3:

[0074] The shortest path from D1 to V3 is: D1V2T1V1T2V3

[0075] The shortest path from D2 to V3 is: D2V5T4V3

[0076] The shortest path from D3 to V3 is: D3V4T3V1T2V3

[0077] The order in which the virtual fault points at both ends of each adjacent measuring point appear in the path when there is more than one virtual fault point is called the fault polarity of the adjacent measuring points:

[0078] V1

[0079] The fault polarity of T1 is: V2V1

[0080] The fault polarity of T2 is: V3V1

[0081] The fault polarity of T3 is: V4V1

[0082] The fault polarity of T4 is: V5V3

[0083] V3

[0084] The fault polarity of T1 is: V2V1

[0085] The fault polarity of T2 is: V1V3

[0086] The fault polarity of T3 is: V4V1

[0087] The fault polarity of T4 is: V5V3

[0088] Compare the fault polarity and standard polarity of the adjacent measuring points of each virtual fault point. If they are opposite, adjust the current polarity of the measuring point to the opposite current polarity:

[0089] For V1, the adjacent measuring points are T1T2T3. The fault polarity of T1 is opposite to the standard polarity. The current polarity of T1 is adjusted to the opposite current polarity.

[0090] For V3, the adjacent measuring points are T2T4, the fault polarity of T2 is opposite to the standard polarity, and the current polarity of T2 is adjusted to the opposite current polarity;

[0091] Determine whether the maximum phase angle difference between all adjacent measuring points of a virtual fault point with more than one adjacent measuring point exceeds the preset threshold. If not, the fault occurs within the range covered by the virtual fault point to all its adjacent measuring points:

[0092] Assume F1 fails.

[0093] V1 has three adjacent measuring points T1T2T3. According to the standard polarity, the current of T1 is in antiphase with the current of T2T3. After the current polarity of T1 is adjusted to the opposite current polarity, the currents of the three measuring points become in phase, and it can be determined that the fault occurs between V1 and T1T2T3, that is, F1.

[0094] V3 has two adjacent measuring points T2T4. According to the standard polarity, the current of T2 is in phase with the current of T4. After the current polarity of T2 is adjusted to the opposite current polarity, the currents of the two measuring points become anti-phase, that is, there is no fault between T2 and T4.

[0095] Please refer to Figure 4 , Figure 4 A structural block diagram of a power grid fault location device provided by an embodiment of the present invention; the specific device may include:

[0096] The measuring point starting polarity adjustment module 100 is used to adjust the starting polarity of all measuring point currents to point to the root node as positive;

[0097] A virtual fault point insertion module 200 is used to insert a virtual fault point between adjacent measuring points, between a measuring point and a root node, and between a measuring point and a leaf node of a power grid;

[0098] The measuring point standard polarity calculation module 300 is used to find the first group of shortest paths from each leaf node to the root node, and record the order in which the virtual fault points at both ends of each measuring point appear in the first group of shortest paths as the standard polarity of each measuring point;

[0099] The measuring point fault polarity calculation module 400 is used to find a second group of shortest paths from the root node and the leaf node to each virtual fault point for more than one adjacent measuring point, and record the order in which the virtual fault points at both ends of the adjacent measuring points of each virtual fault point appear in the second group of shortest paths as the fault polarity of the adjacent measuring points of each virtual fault point;

[0100] The current polarity adjustment module 500 is used to compare the fault polarity and standard polarity of the adjacent measuring points of each virtual fault point, and if they are opposite, adjust the current polarity of the measuring point to the opposite current polarity;

[0101] The fault location module 600 is used to determine whether the maximum phase angle difference between all adjacent measuring points of a virtual fault point with more than one adjacent measuring point exceeds a preset threshold. If not, the fault occurs within the range covered by the virtual fault point to all its adjacent measuring points.

[0102] The power grid fault locating device of this embodiment is used to implement the aforementioned power grid fault locating method. Therefore, the specific implementation method of the power grid fault locating device can be seen in the embodiment part of the aforementioned power grid fault locating method. For example, the measuring point starting polarity adjustment module 100, the virtual fault point insertion module 200, the measuring point standard polarity calculation module 300, the measuring point fault polarity calculation module 400, the current polarity adjustment module 500, and the fault locating module 600 are respectively used to implement steps S201, S202, S203, S204, S205 and S206 in the aforementioned power grid fault locating method. Therefore, its specific implementation method can refer to the description of the corresponding various partial embodiments, which will not be repeated here.

[0103] A specific embodiment 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 steps of the above-mentioned power grid fault location method are implemented.

[0104] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0105] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0106] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0108] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for locating a power grid fault, characterized in that: include: Adjust the starting polarity of all measuring point currents to point to the root node as positive; Insert virtual fault points between adjacent measuring points of the power grid, between measuring points and root nodes, and between measuring points and leaf nodes; Find the first group of shortest paths from each leaf node to the root node, and record the order in which the virtual fault points at both ends of each measuring point appear in the first group of shortest paths as the standard polarity of each measuring point; For virtual fault points with more than one adjacent measuring point, find the second group of shortest paths from the root node and the leaf node to each virtual fault point, and record the order in which the virtual fault points at both ends of the adjacent measuring points of each virtual fault point appear in the second group of shortest paths as the fault polarity of the adjacent measuring points of each virtual fault point; Compare the fault polarity and standard polarity of the adjacent measuring points of each virtual fault point. If they are opposite, adjust the current polarity of the measuring point to the opposite current polarity. It is determined whether the maximum phase angle difference between all adjacent measuring points of a virtual fault point with more than one adjacent measuring point exceeds a preset threshold. If not, the fault occurs within the range covered by the virtual fault point to all its adjacent measuring points.

2. The power grid fault location method according to claim 1, characterized in that: After inserting virtual fault points between adjacent measuring points, between a measuring point and a root node, and between a measuring point and a leaf node of the power grid, the method further includes: Merge the virtual failure points at the branches.

3. The power grid fault location method according to claim 1, characterized in that: For the virtual fault point with more than one adjacent measuring point, the second group of shortest paths from the root node and the leaf node to each virtual fault point is found, and the order in which the virtual fault points at both ends of the adjacent measuring points of each virtual fault point appear in the second group of shortest paths is recorded as the fault polarity of each adjacent measuring point of the virtual fault point, and further includes: The current amplitude change is used as a criterion to roughly determine the fault range, and the next step of calculation is performed within the fault range.

4. The power grid fault location method according to claim 1, characterized in that: If the maximum phase angle difference between all adjacent measuring points of more than one virtual fault point exceeds the preset threshold, the fault is between a root node and its adjacent measuring points or between a leaf node and its adjacent measuring points.

5. The power grid fault location method according to claim 4, characterized in that: If the fault is between a root node and its adjacent measuring point or between a leaf node and its adjacent measuring point, the current amplitude change is used as a criterion for further positioning.

6. The power grid fault location method according to claim 5, characterized in that: The algorithm for fault location using the change of current amplitude as a criterion includes a current mutation method and a current difference method.

7. The power grid fault location method according to claim 1, characterized in that: The preset threshold is 90°.

8. A power grid fault location device, characterized in that: include: The measuring point starting polarity adjustment module is used to adjust the starting polarity of all measuring point currents to point to the root node as positive; A virtual fault point insertion module is used to insert a virtual fault point between adjacent measuring points, between a measuring point and a root node, and between a measuring point and a leaf node of the power grid; A measuring point standard polarity calculation module is used to find the first group of shortest paths from each leaf node to the root node, and record the order in which the virtual fault points at both ends of each measuring point appear in the first group of shortest paths as the standard polarity of each measuring point; A measuring point fault polarity calculation module is used to find a second group of shortest paths from the root node and the leaf node to each virtual fault point for more than one adjacent measuring point, and record the order in which the virtual fault points at both ends of the adjacent measuring points of each virtual fault point appear in the second group of shortest paths as the fault polarity of the adjacent measuring points of each virtual fault point; A current polarity adjustment module is used to compare the fault polarity and standard polarity of the adjacent measuring points of each virtual fault point. If they are opposite, the current polarity of the measuring point is adjusted to the opposite current polarity. The fault location module is used to determine whether the maximum phase angle difference between all adjacent measuring points of a virtual fault point with more than one adjacent measuring point exceeds a preset threshold. If not, the fault occurs within the range covered by the virtual fault point to all its adjacent measuring points.

9. The power grid fault locating device according to claim 8 is applied to a tree-structured power grid with direct electrical connections.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the power grid fault location method according to any one of claims 1 to 7 are implemented.

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