A method for identifying topological changes in a distribution network for optimizing traveling wave location

Abstract

The present invention provides a method for identifying topological changes in a distribution network for optimizing traveling wave positioning, which relates to the technical field of distribution network operation and maintenance. The present invention realizes the identification of line topological changes by establishing an initial matrix of the time difference of traveling wave heads between devices and using the traveling wave signals generated by the distribution network itself when a fault occurs; this method only requires injecting a current traveling wave signal into the line head manually once after installing the distribution network terminal measurement device, and then the topological changes of the distribution network can be automatically identified when a fault occurs. If the distances between line devices are known, there is no need to inject traveling waves manually. Compared with the prior art, the present invention does not need to repeatedly inject signals into the line, which affects the normal operation of the line. At the same time, this method makes use of the characteristic that distribution network faults occur frequently, so that the line topology can be frequently detected for changes.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network operation and maintenance, and particularly to a method for identifying distribution network topology changes for optimizing traveling wave positioning. Background Art

[0002] The operating environment of the distribution network is complex and often suffers from external forces such as lightning, wildfires, and trees, resulting in faults and power outages for users, affecting production and life. Therefore, we need a technology to quickly and accurately locate the fault points of the distribution network to ensure the normal operation of the distribution network.

[0003] For this reason, some people have proposed using the double - end traveling wave positioning technology to accurately locate the fault points, thereby reducing the fault troubleshooting time. For example, the invention application with the application number CN201910837470.6 proposed an improved double - end traveling wave fault ranging method to quickly locate the fault points.

[0004] However, the traveling wave positioning method is affected by the frequent changes in the distribution network topology. After the distribution network topology changes, the traveling wave positioning accuracy will be greatly reduced. At the same time, there are many users and complex wiring in the distribution network. Currently, most of the topology data is manually input into the computer system, with low accuracy and lack of effective verification means, which further reduces the traveling wave positioning accuracy.

[0005] Currently, there are mainly the following methods for identifying distribution network topology changes: (1) Manually opening and closing switches supplemented by on - site observation to identify the connection relationship of the power grid lines. This method is relatively clumsy, time - consuming and labor - intensive. (2) Power line carrier communication technology. A handheld terminal injects pulsed current into the line, and the phase sequence information sent after being detected and identified by the receiving display host is used to identify the distribution network topology changes. Although this method can identify the distribution network topology changes, it requires manual injection of pulsed current signals each time, and the injected pulsed current signals will also have a certain impact on the actual operation of the power grid.

[0006] From the above background, it is not difficult to see that before using the double - end traveling wave positioning technology to locate the fault points, it is necessary to first identify whether the distribution network topology has changed, so as to reduce the impact of distribution network topology changes on the traveling wave positioning results.

[0007] Therefore, it is necessary to provide a method for identifying distribution network topology changes for optimizing traveling wave positioning to solve the above technical problems. Summary of the Invention

[0008] To solve one of the above technical problems, the present invention provides a method for identifying topological changes in a distribution network for optimizing traveling wave positioning. A current traveling wave emitting device is provided at the head end of the distribution network line, and a distribution network terminal measuring device is respectively provided at each detection node of the distribution network; the current traveling wave emitting device is used to generate a current traveling wave signal, and the current traveling wave signal propagates through the distribution network and finally reaches the end of each line; the distribution network terminal measuring device is used to collect the current traveling wave signal and record the wave head time of the detected current traveling wave signal.

[0009] Further, when the installation of each power equipment in the distribution network is completed: establish an initial matrix of the wave head time difference between devices; the initial matrix of the wave head time difference between devices is used to record the propagation time characteristics of the distribution network line topology, including the initial matrix of the wave head time difference at the head end and the initial matrix of the wave head time difference at the end; inject a current traveling wave signal at the head end of the line through the current traveling wave emitting device, each detection node collects the wave head time, and calculates the difference between the wave head times of adjacent detection nodes to form a matrix to obtain the initial matrix of the wave head time difference at the head end; obtain the initial matrix of the wave head time difference at the end through the operation of the initial matrix of the wave head time difference at the head end and the current traveling wave transmission characteristics.

[0010] Further, when a line fails: preliminarily locate the fault point and verify the identification of topological changes in the line; the verification of the identification of topological changes in the line includes the verification of topological changes on the large-number side of the fault point and the verification of topological changes on the small-number side of the fault point.

[0011] Further, the verification of topological changes on the large-number side of the fault point is used to verify whether the line topology on the large-number side of the fault point has changed. Each detection node on the large-number side of the fault point collects the current traveling wave signal emitted by the fault point to obtain the wave head time of the fault traveling wave on the large-number side; compare the difference between the wave head time of the fault traveling wave on the large-number side and the wave head time of the corresponding detection node in the initial matrix of the wave head time difference at the head end respectively; if the difference comparison exceeds the set threshold, it is considered that the line topology on the large-number side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the large-number side of the fault point has not changed.

[0012] Further, the verification of topological changes on the small-number side of the fault point is used to verify whether the line topology on the small-number side of the fault point has changed. Each detection node on the small-number side of the fault point collects the current traveling wave signal emitted by the fault point to obtain the wave head time of the fault traveling wave on the small-number side; compare the difference between the wave head time of the fault traveling wave on the small-number side and the wave head time of the corresponding detection node in the initial matrix of the wave head time difference at the end respectively; if the difference comparison exceeds the set threshold, it is considered that the line topology on the small-number side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the small-number side of the fault point has not changed.

[0013] As a more specific solution, the line topology change identification and verification is also started when a traveling wave is introduced into the line or a switch is opened or closed, and verifies whether the line topology has changed.

[0014] As a more specific solution, the fault point can be preliminarily located by using the amplitude and phase comparison method or the traveling wave polarity method.

[0015] As a more specific solution, the detection node includes a line end node and a line transmission node; the line end node is set on the end line, and the line transmission node is set on the transmission line.

[0016] As a more specific solution, the initial matrix of the time difference of the first-end traveling wave header is constructed by the following steps:

[0017] A1 current traveling wave transmitter transmits a primary current traveling wave signal to the distribution network;

[0018] Each detection node A2 collects the current traveling wave signal through the distribution network terminal measurement device and records the traveling wave head time T of the detected current traveling wave signal. i , where i is the detection node number;

[0019] A3 calculates the time difference of the traveling wave head between two adjacent detection nodes in the direction from the beginning to the end;

[0020] A4 constructs the initial matrix of time difference of the first-end traveling wave header: A=[T1-T2, T2-T3, T3-T4,…, T n-1 -T n ], where n is the total number of detection nodes and A is the initial matrix of the time difference of the head of the traveling wave.

[0021] As a more specific solution, the initial matrix of the terminal traveling wave head time difference is constructed through the following steps:

[0022] B1 reads the initial matrix of time difference of the first-end traveling wave header;

[0023] B2 brings the initial matrix of the time difference between the first and last traveling wave heads into the current traveling wave transmission characteristic calculation formula to obtain the initial matrix of the time difference between the last and last traveling wave heads. The current traveling wave transmission characteristic calculation formula is:

[0024]

[0025] Where n is the total number of detection nodes, A is the initial matrix of the time difference of the first-end traveling wave header, and B is the initial matrix of the time difference of the last-end traveling wave header.

[0026] As a more specific solution, the topology change identification and verification on the main side of the fault point is performed through the following steps:

[0027] Each detection node of C1 continuously monitors the distribution network through the distribution network terminal measuring device;

[0028] When a fault occurs in the line, each detection node of C2 collects the current traveling wave signal emitted by the fault point through the distribution network terminal measuring device and records the time of the wave head of the collected traveling wave;

[0029] C3 Initially locate the fault interval of the fault point in the distribution network;

[0030] C4 Collect the time of the wave head of the traveling wave recorded by the detection node on the large side of the fault point to obtain the time of the wave head of the fault traveling wave on the large side; C5 Calculate the time difference between the times of the wave heads of the fault traveling waves on the large sides of two adjacent large sides in the direction from the head end to the end;

[0031] C6 Construct a time difference matrix of the wave heads of the fault traveling waves on the large side: D = [T k+1 -T k+2 , T k+2 -T k+3 , T k+3 -T k+4 , …, T n-1 -T n ; where K represents the detection node number in the fault interval; D represents the time difference matrix of the wave heads of the fault traveling waves on the large side;

[0032] C7 Compare the time difference of the wave heads of the fault traveling waves on the large side with the time difference of the wave heads of the corresponding detection nodes in the initial matrix of the time difference of the wave heads at the head end; if the difference comparison exceeds the set threshold, it is considered that the line topology on the large side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the large side of the fault point has not changed.

[0033] As a more specific solution, the identification and verification of the topology change on the small side of the fault point are carried out through the following steps:

[0034] D1 Each detection node continuously monitors the distribution network through the distribution network terminal measuring device;

[0035] D2 When a fault occurs in the line, each detection node collects the current traveling wave signal emitted by the fault point through the distribution network terminal measuring device and records the time of the wave head of the collected traveling wave;

[0036] D3 Initially locate the fault interval of the fault point in the distribution network;

[0037] D4 Collect the time of the wave head of the traveling wave recorded by the detection node on the small side of the fault point to obtain the time of the wave head of the fault traveling wave on the small side; D5 Calculate the time difference between the times of the wave heads of the fault traveling waves on the small sides of two adjacent small sides in the direction from the end to the head end;

[0038] D6 Construct the wavefront time difference matrix of the small-side fault line of the D6 component: C = [T k -T k-1 , T k-1 -T k-2 , T k-2 -T k-3 ,..., T2 - T1]; where K represents the detection node number within the fault interval; C represents the wavefront time difference matrix of the small-side fault line;

[0039] D7 Compare the wavefront time difference of the small-side fault line with the wavefront time of the corresponding detection node in the initial matrix of the wavefront time difference of the end line; if the difference comparison exceeds the set threshold, it is considered that the line topology on the small side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the small side of the fault point has not changed.

[0040] As a more specific solution, the wavefront time difference between two detection nodes can also be calculated through the following steps:

[0041] E1 Obtain the line length L between the two detection nodes i,j , where i and j are the numbers of the two detection nodes respectively;

[0042] E2 Obtain the transmission rate v of the current traveling wave signal between the lines;

[0043] E3 Through the formula: Obtain the wavefront time difference between the two detection nodes.

[0044] As a more specific solution, when a line fails:

[0045] If both the large-side topology change identification verification of the fault point and the small-side topology change identification verification of the fault point determine that the line topology has not changed, it is determined that the overall line topology of the distribution network has not changed, and the fault point location continues to be executed;

[0046] If either the large-side topology change identification verification of the fault point or the small-side topology change identification verification of the fault point determines that the line topology has changed, perform topology update on the changed large side / small side. After the update is completed, continue to execute the fault point location;

[0047] If both the large-side topology change identification verification of the fault point and the small-side topology change identification verification of the fault point determine that the line topology has changed, perform topology update on the overall line topology of the distribution network. After the update is completed, continue to execute the fault point location.

[0048] Compared with the related technology, a method for identifying topology changes in a distribution network for optimizing traveling wave positioning provided by the present invention has the following beneficial effects:

[0049] The present invention realizes the identification of line topology changes by establishing an initial matrix of the time difference of traveling wave heads between devices and using the traveling wave signals generated by the distribution network itself when a fault occurs; this method only requires injecting a current traveling wave signal into the head end of the line manually once after installing the distribution network terminal measurement device, and then the distribution network topology change situation can be automatically identified when a fault occurs. If the distances between line devices are known, there is no need to inject traveling waves manually. Compared with the prior art, the present invention does not need to repeatedly inject signals into the line, which affects the normal operation of the line. At the same time, this method makes use of the characteristic that distribution network faults occur frequently, so that the line topology can be frequently detected for changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 FIG. is a preferred flowchart showing a method for identifying distribution network topology changes for optimizing traveling wave positioning provided by an embodiment of the present invention;

[0051] Figure 2 FIG. is a schematic diagram of the line topology structure of a certain distribution network provided by an embodiment of the present invention for illustration. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] The present invention will be further described below in conjunction with the drawings and embodiments.

[0053] As Figure 1 shown, a method for identifying distribution network topology changes for optimizing traveling wave positioning provided by this embodiment sets a current traveling wave transmitting device at the head end of the line of the distribution network, and sets distribution network terminal measurement devices at each detection node of the distribution network; the current traveling wave transmitting device is used to generate a current traveling wave signal, and the current traveling wave signal propagates through the distribution network and finally reaches the ends of each line; the distribution network terminal measurement device is used to collect the current traveling wave signal and record the traveling wave head time of the detected current traveling wave signal.

[0054] Furthermore, when all power equipment in the distribution network is installed: an initial matrix of the time difference of traveling wave heads between devices is established; the initial matrix of the time difference of traveling wave heads between devices is used to record the propagation time characteristics of the distribution network line topology, including the initial matrix of the time difference of traveling wave heads at the head end and the initial matrix of the time difference of traveling wave heads at the end; a current traveling wave signal is injected into the head end of the line through the current traveling wave transmitting device, each detection node collects the traveling wave head time, and the difference between the traveling wave head times of adjacent detection nodes is calculated to form a matrix to obtain the initial matrix of the time difference of traveling wave heads at the head end; the initial matrix of the time difference of traveling wave heads at the end is obtained through the operation of the initial matrix of the time difference of traveling wave heads at the head end and the current traveling wave transmission characteristics.

[0055] Further, when a line fault occurs: initially locate the fault point and perform line topology change identification and verification; the line topology change identification and verification includes fault point large-side topology change identification and verification and fault point small-side topology change identification and verification.

[0056] Further, the fault point large-side topology change identification and verification is used to verify whether the line topology on the large side of the fault point has changed. The current traveling wave signals emitted by the fault point are collected by each detection node on the large side of the fault point to obtain the wavefront time of the large-side fault traveling wave; the wavefront time of the large-side fault traveling wave is respectively compared with the wavefront time of the corresponding detection node in the initial matrix of the wavefront time difference between the head end and the large side; if the difference comparison exceeds the set threshold, it is considered that the line topology on the large side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the large side of the fault point has not changed.

[0057] Further, the fault point small-side topology change identification and verification is used to verify whether the line topology on the small side of the fault point has changed. The current traveling wave signals emitted by the fault point are collected by each detection node on the small side of the fault point to obtain the wavefront time of the small-side fault traveling wave; the wavefront time of the small-side fault traveling wave is respectively compared with the wavefront time of the corresponding detection node in the initial matrix of the wavefront time difference between the end and the small side; if the difference comparison exceeds the set threshold, it is considered that the line topology on the small side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the small side of the fault point has not changed.

[0058] It should be noted that: a method for identifying changes in the distribution network topology for optimizing traveling wave positioning proposed in this embodiment is mainly to perform distribution network topology identification on the distribution network before accurately positioning the fault point using current traveling waves, so as to reduce the traveling wave positioning error. The current traveling wave waveform data is collected by a distribution network terminal measurement device in the distribution network power system. A traveling wave acquisition module is installed on the distribution network terminal measurement device. When a line fault occurs, a current traveling wave signal will be generated, and the signal will be transmitted from the fault point to both ends and spread throughout the entire line. This invention patent uses the distribution network terminal measurement device to collect traveling wave signals, extract the wavefront time, and identify whether the distribution line topology has changed by calculating the time difference of the traveling waves collected between devices.

[0059] As a more specific solution, the line topology change identification and verification is also started when a traveling wave is inserted into the line or a switch is switched on or off, and it is verified whether the line topology has changed.

[0060] It should be noted that: for the method proposed in this embodiment, only a current traveling wave signal needs to be injected manually at the head end of the line once after the equipment is installed to obtain the initial matrix of the head and tail traveling wave head time differences. There is no need for manual traveling wave injection in the future. At the same time, the proposed method will perform a line topology verification every time a line fault occurs, or when an external traveling wave enters the line, or when a switch is switched on or off. The verification does not require additional traveling wave injection and only needs to detect the traveling wave to verify whether the topology structure of the distribution network has changed.

[0061] As a more specific solution, the fault point is preliminarily located by the amplitude and phase comparison method or the traveling wave polarity method.

[0062] As a more specific solution, the detection nodes include the line end node and the line transmission node; the line end node is set on the end line, and the line transmission node is set on the transmission line.

[0063] As a more specific solution, the initial matrix of the head traveling wave head time difference is constructed through the following steps:

[0064] A1 The current traveling wave transmitting device emits a current traveling wave signal to the distribution network.

[0065] A2 Each detection node collects the current traveling wave signal through the distribution network terminal measurement device and records the traveling wave head time T of the detected current traveling wave signal i , where i is the detection node label;

[0066] A3 Calculate the traveling wave head time difference between two adjacent detection nodes in the direction from the head end to the tail end.

[0067] A4 Form the initial matrix of the head traveling wave head time difference: A = [T1 - T2, T2 - T3, T3 - T4, …, T n-1 -T n , where n is the total number of detection nodes, and A is the initial matrix of the head traveling wave head time difference.

[0068] It should be noted that: after the distribution network terminal measurement device is installed on the line, a current traveling wave signal is injected into the line at the head end of the line by using the current traveling wave transmitting device, and then the traveling wave head time Tn is extracted according to the traveling wave signals collected by each distribution network terminal measurement device on the line. n is the equipment number on this line, and the fault point is calculated to be located in the initial matrix A of the head traveling wave head time difference. According to the current traveling wave transmission characteristics, when the fault point is located at the end of the line, the initial matrix B of the end traveling wave head time difference can be derived through the calculation formula.

[0069] As a more specific solution, the initial matrix of the end traveling wave head time difference is constructed through the following steps:

[0070] B1 reads the initial matrix of the head-end traveling wave head time difference;

[0071] B2 substitutes the initial matrix of the head-end traveling wave head time difference into the calculation formula of the current traveling wave transmission characteristics to obtain the initial matrix of the tail-end traveling wave head time difference. The calculation formula of the current traveling wave transmission characteristics is:

[0072]

[0073] where n is the total number of detection nodes, A is the initial matrix of the head-end traveling wave head time difference, and B is the initial matrix of the tail-end traveling wave head time difference.

[0074] As a more specific solution, the identification and verification of the topological change on the large-number side of the fault point are carried out through the following steps:

[0075] C1 Each detection node continuously monitors the distribution network through the distribution network terminal measurement device;

[0076] C2 When a fault occurs on the line, each detection node collects the current traveling wave signal sent by the fault point through the distribution network terminal measurement device and records the time of the collected traveling wave head;

[0077] C3 Initially locate the fault interval of the fault point in the distribution network;

[0078] C4 Collect the time of the traveling wave head recorded by the detection node on the large-number side of the fault point to obtain the large-number side fault traveling wave head time; C5 Calculate the time difference between the traveling wave head times of two adjacent large-number side fault traveling waves in the direction from the head-end to the tail-end;

[0079] C6 Form the large-number side fault traveling wave head time difference matrix:

[0080] D = [T k+1 -T k+2 , T[[ID=3�]] k+2 -T k+3 , T k+3 -T k+4 , …, T n-1 -T n ; where K represents the detection node number in the fault interval; D represents the large-number side fault traveling wave head time difference matrix;

[0081] C7 Compare the difference between the large-number side fault traveling wave head time difference matrix and the traveling wave head time of the corresponding detection node in the initial matrix of the head-end traveling wave head time difference; if the difference comparison exceeds the set threshold, it is considered that the line topology on the large-number side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the large-number side of the fault point has not changed.

[0082] As a more specific solution, the identification and verification of the topological change on the small side of the fault point are carried out through the following steps:

[0083] D1 Each detection node continuously monitors the distribution network through the distribution network terminal measuring device;

[0084] D2 When a line fault occurs, each detection node collects the current traveling wave signal emitted by the fault point through the distribution network terminal measuring device and records the time of the wavefront of the collected traveling wave;

[0085] D3 Initially locate the fault interval of the fault point in the distribution network;

[0086] D4 Collect the time of the wavefront of the traveling wave recorded by the detection nodes on the small side of the fault point to obtain the time of the wavefront of the fault traveling wave on the small side; D5 Calculate the time difference between the wavefront times of two adjacent fault traveling waves on the small side in the direction from the end to the head;

[0087] D6 Form a time difference matrix of the wavefront times of the fault traveling waves on the small side: C = [T k -T k-1 , T k-1 -T k-2 , T k-2 -T k-3 , …, T2 - T1]; where K represents the detection node number in the fault interval; C represents the time difference matrix of the wavefront times of the fault traveling waves on the small side;

[0088] D7 Compare the difference between the time difference matrix of the wavefront times of the fault traveling waves on the small side and the wavefront time of the corresponding detection node in the initial matrix of the time difference of the wavefront times at the end; if the difference comparison exceeds the set threshold, it is considered that the line topology on the small side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the small side of the fault point has not changed.

[0089] As a more specific solution, the time difference of the wavefront times between two detection nodes can also be calculated through the following steps:

[0090] E1 Obtain the line length L between the two detection nodes i,j , where i and j are the numbers of the two detection nodes respectively;

[0091] E2 Obtain the transmission rate v of the current traveling wave signal between the lines;

[0092] E3 Through the formula: Obtain the time difference of the wavefront times between the two detection nodes.

[0093] As a more specific solution, when a line fault occurs:

[0094] If it is determined that the line topology has not changed in both the verification of topology change identification on the larger-number side of the fault point and the verification of topology change identification on the smaller-number side of the fault point, it is determined that the overall line topology of the distribution network has not changed, and the fault point location is continued to be executed;

[0095] If it is determined that the line topology has changed in either the verification of topology change identification on the larger-number side of the fault point or the verification of topology change identification on the smaller-number side of the fault point, the topology of the changed larger-number side / smaller-number side is updated. After the update is completed, the fault point location is continued to be executed;

[0096] If it is determined that the line topology has changed in both the verification of topology change identification on the larger-number side of the fault point and the verification of topology change identification on the smaller-number side of the fault point, the overall line topology of the distribution network is updated. After the update is completed, the fault point location is continued to be executed.

[0097] It should be noted that: as Figure 2 shown, in a specific embodiment, the larger-number side refers to from Substation A to Substation B; the smaller-number side refers to from Substation B to Substation A; when a fault occurs, it is separated by a disconnector pair, and the normal operation of the power grid is maintained by using a tie switch; each labeled point in the figure is a detection node. It is not difficult to see from the figure that the line end nodes are set on the end lines, and the line transmission nodes are set on the transmission lines; these detection nodes can monitor and record traveling waves; through the method of this embodiment, the topology structure of the distribution network can be quickly detected, thereby improving the accuracy of fault location.

[0098] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning, characterized in that, A current traveling wave transmitting device is arranged at the head end of the distribution network line, and a distribution network terminal measuring device is respectively arranged at each detection node of the distribution network; the current traveling wave transmitting device is used to generate a current traveling wave signal, and the current traveling wave signal propagates through the distribution network and finally reaches the end of each line; the distribution network terminal measuring device is used to collect the current traveling wave signal and record the wave head time of the detected current traveling wave signal. When all power equipment in the distribution network is installed: establish an initial matrix of the wave head time difference between devices; the initial matrix of the wave head time difference between devices is used to record the propagation time characteristics of the distribution network line topology, including the initial matrix of the wave head time difference at the head end and the initial matrix of the wave head time difference at the end; inject a current traveling wave signal at the head end of the line through the current traveling wave transmitting device, collect the wave head time at each detection node, and calculate the difference between the wave head times of adjacent detection nodes to form a matrix to obtain the initial matrix of the wave head time difference at the head end; obtain the initial matrix of the wave head time difference at the end through the operation of the initial matrix of the wave head time difference at the head end and the current traveling wave transmission characteristics. When a line fails: preliminarily locate the fault point and perform line topology change identification and verification; the line topology change identification and verification include the topology change identification and verification on the large-number side of the fault point and the topology change identification and verification on the small-number side of the fault point. The topology change identification and verification on the large-number side of the fault point is used to verify whether the line topology on the large-number side of the fault point has changed. The current traveling wave signals emitted by the fault point are collected by each detection node on the large-number side of the fault point to obtain the wave head time of the fault traveling wave on the large-number side; compare the wave head time of the fault traveling wave on the large-number side with the wave head time of the corresponding detection node in the initial matrix of the wave head time difference at the head end respectively; if the difference comparison exceeds the set threshold, it is considered that the line topology on the large-number side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the large-number side of the fault point has not changed. The topology change identification and verification on the small-number side of the fault point is used to verify whether the line topology on the small-number side of the fault point has changed. The current traveling wave signals emitted by the fault point are collected by each detection node on the small-number side of the fault point to obtain the wave head time of the fault traveling wave on the small-number side; compare the wave head time of the fault traveling wave on the small-number side with the wave head time of the corresponding detection node in the initial matrix of the wave head time difference at the end respectively; if the difference comparison exceeds the set threshold, it is considered that the line topology on the small-number side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the small-number side of the fault point has not changed.

2. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 1, characterized in that, 3. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 1, characterized in that, The line topology change identification and verification is also started when a traveling wave is inserted into the line or a switch is switched on or off, and it is verified whether the line topology has changed.

4. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 1, characterized in that, Preliminarily locate the fault point by the amplitude-phase comparison method or the traveling wave polarity method.

5. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 1, characterized in that The detection nodes include line end nodes and line transmission nodes; the line end nodes are arranged on the end lines, and the line transmission nodes are arranged on the transmission lines. The initial matrix of the wave head time difference at the head end is constructed through the following steps: A1 The current traveling wave transmitting device emits a primary current traveling wave signal to the distribution network. Each detection node of A2 collects current traveling wave signals through the distribution network terminal measurement device and records the wave head time T of the detected current traveling wave signals i , where i is the label of the detection node; Calculate the time difference of the traveling wave heads between two adjacent detection nodes in the direction from the head end to the tail end; Initial matrix of head - end traveling - wave head - wave time difference for A4 component: A = [T1 - T2, T2 - T3, T3 - T4,..., T n-1 - T n , where n is the total number of detection nodes, and A is the initial matrix of head - end traveling - wave head - wave time difference.

6. The method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 5, wherein, The initial matrix of the traveling wave head time difference at the tail end is constructed through the following steps: B1 Read the initial matrix of the traveling wave head time difference at the head end; B2 Substitute the initial matrix of the traveling wave head time difference at the head end into the calculation formula of the current traveling wave transmission characteristics to obtain the initial matrix of the traveling wave head time difference at the tail end. The calculation formula of the current traveling wave transmission characteristics is: Where n is the total number of detection nodes, A is the initial matrix of the traveling wave head time difference at the head end, and B is the initial matrix of the traveling wave head time difference at the tail end.

7. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 6, characterized in that, The identification and verification of the topological change on the larger-number side of the fault point are carried out through the following steps: C1 Each detection node continuously monitors the distribution network through the distribution network terminal measurement device; C2 When a fault occurs on the line, each detection node collects the current traveling wave signal sent by the fault point through the distribution network terminal measurement device and records the time of the collected traveling wave head; C3 Initially locate the fault interval of the fault point in the distribution network; C4 Collect the time of the traveling wave head recorded by the detection node on the larger-number side of the fault point to obtain the traveling wave head time of the larger-number side fault; C5 Calculate the time difference between the traveling wave heads of two adjacent larger-number side fault points in the direction from the head end to the tail end; Construct the large-size side fault traveling wave head time difference matrix for C6: D = [T k+1 - T k+2 , T k+2 - T k+3 , T k+3 - T k+4 ,..., T n-1 - T n ; where k represents the detection node number within the fault interval; D represents the large-size side fault traveling wave head time difference matrix; C7 Compare the time difference matrix of the traveling wave heads on the larger-number side of the fault with the traveling wave head time of the corresponding detection node in the initial matrix of the traveling wave head time difference at the head end. If the difference comparison exceeds the set threshold, it is considered that the line topology on the larger-number side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the larger-number side of the fault point has not changed.

8. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 7, characterized in that, The identification and verification of the topological change on the smaller-number side of the fault point are carried out through the following steps: D1 Each detection node continuously monitors the distribution network through the distribution network terminal measurement device; D2 When a fault occurs on the line, each detection node collects the current traveling wave signal sent by the fault point through the distribution network terminal measurement device and records the time of the collected traveling wave head; D3 Initially locate the fault interval of the fault point in the distribution network; D4 Collect the time of the traveling wave head recorded by the detection node on the smaller-number side of the fault point to obtain the traveling wave head time of the smaller-number side fault; D5 Calculate the time difference between the traveling wave heads of two adjacent smaller-number side fault points in the direction from the tail end to the head end; D6 Small-sized side fault traveling wave head time difference matrix formation: C = [T k -T k-1 , T k-1 -T k-2 , T k-2 -T k-3 , …, T2 - T1]; where k represents the detection node number within the fault interval; C represents the small-sized side fault traveling wave head time difference matrix; D7 Compare the time difference matrix of the traveling wave heads on the smaller-number side of the fault with the traveling wave head time of the corresponding detection node in the initial matrix of the traveling wave head time difference at the tail end. If the difference comparison exceeds the set threshold, it is considered that the line topology on the smaller-number side of the fault point has changed; if the difference comparison does not exceed the set threshold, it is considered that the line topology on the smaller-number side of the fault point has not changed.

9. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 1, characterized in that, The time difference of the traveling wave heads between two detection nodes can also be calculated through the following steps: E1 obtains the line length L between two detection nodes i,j , where i and j are the numbers of the two detection nodes respectively; E2 Obtain the transmission rate v of the current traveling wave signal between lines; E3 obtains the traveling wave head time difference between two detection nodes through the formula: ​ 10. A method for identifying topological changes in a distribution network for optimizing traveling wave positioning according to claim 1, characterized in that, When a fault occurs on the line: If both the identification and verification of the topological change on the larger-number side of the fault point and the identification and verification of the topological change on the smaller-number side of the fault point determine that the line topology has not changed, it is considered that the overall line topology of the distribution network has not changed, and continue to perform fault point location; If any of the topology change identification and verification on the large-number side of the fault point and the topology change identification and verification on the small-number side of the fault point determines that the line topology has changed, then perform topology update on the changed large-number side / small-number side. After the update is completed, continue with fault point location; If both the topology change identification and verification on the large-number side of the fault point and the topology change identification and verification on the small-number side of the fault point determine that the line topology has changed, then perform topology update on the overall line topology of the distribution network. After the update is completed, continue with fault point location.

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