Fault breakpoint position searching method based on dichotomy

Abstract

The invention provides a fault breakpoint position searching method based on a dichotomy, and the method specifically comprises the steps: obtaining a distribution network line where a fault occurs, and obtaining corresponding historical broken line fault data; performing feature extraction on the historical broken line fault data, and constructing a position judgment rule of a fault breakpoint according to the extracted fault features; performing center position query on the distribution network line based on the topological information of the distribution network line; and performing anomaly identification on the electrical data at the central position, and searching a fault breakpoint position according to an anomaly identification result and a position judgment rule to obtain the fault breakpoint position. According to the method, the position judgment rules of different fault scenes can be constructed by mining historical broken line fault data features so as to adapt to fault breakpoint position search in different fault scenes, the search accuracy is guaranteed, the search range of the fault breakpoint position is further gradually narrowed through the dichotomy, and the search efficiency of the fault breakpoint position is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network fault processing, and in particular to a method for finding a fault breakpoint location based on a dichotomy method. Background Art

[0002] Distribution lines, a crucial link in power transmission and distribution, directly serve end users, and their operational status is directly related to the quality of power supply. However, distribution lines are widely distributed and operate in a complex environment. They are susceptible to a variety of factors, including natural factors, equipment aging, and external damage, leading to frequent line disconnections. Once a line disconnection occurs, failure to quickly and accurately locate the fault point will severely hamper the efficiency of repairs, resulting in prolonged power outages, inconvenience for users, and even potentially leading to more serious safety incidents.

[0003] Currently, fault location on distribution network lines primarily relies on traditional manual inspections and some automated detection methods. Manual inspections are relatively intuitive and highly adaptable to fault scenarios, but they suffer from low efficiency, high labor intensity, and limitations imposed by weather and geographical conditions. Inspections are particularly challenging in remote mountainous areas and complex terrain, making it difficult to quickly locate fault points. Existing automated detection methods, such as impedance-based and traveling wave-based fault location technologies, can improve fault location efficiency to a certain extent. However, in complex distribution network environments, this single-fault feature-based approach struggles to address the diverse fault types present in distribution network lines, and the accuracy of fault location cannot be guaranteed. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art in that when manual inspection and partial automated detection means are used to locate the fault breakpoints of distribution network lines, the efficiency and accuracy of the fault breakpoint location cannot be guaranteed at the same time. A method for finding the location of a fault breakpoint based on a binary search method is provided. By mining the characteristics of historical line break fault data, the fault characteristics under different fault scenarios are determined, and then corresponding fault breakpoint location judgment rules are constructed according to the fault characteristics. The method is adapted to the fault breakpoint location search under different fault scenarios and ensures the accuracy of fault location. On the basis of the location judgment rules, a central position query is performed according to the topological information, so that the fault breakpoint position is quickly found through a binary search method based on the abnormal identification of the central position. While ensuring the accuracy of fault location, the efficiency of finding the fault breakpoint position is improved.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The fault breakpoint location finding method based on the dichotomy method includes:

[0007] Obtain the distribution network line where the fault occurred and obtain the corresponding historical disconnection fault data;

[0008] Extract features from historical disconnection fault data and build fault breakpoint location judgment rules based on the extracted fault features;

[0009] Based on the topological information of the distribution network line, the center location of the distribution network line is queried;

[0010] The electrical data at the center position is anomaly identified, and the fault breakpoint location is searched based on the anomaly identification results and position judgment rules to obtain the fault breakpoint location.

[0011] Furthermore, the feature extraction of historical disconnection fault data and the construction of fault breakpoint location judgment rules based on the extracted fault features include:

[0012] Based on the occurrence time and cause of the disconnection fault, a fault scenario corresponding to each disconnection fault is constructed;

[0013] Extract features from historical disconnection fault data for each fault scenario and classify the acquired fault features according to their corresponding location information;

[0014] Based on the classified fault characteristics, the location judgment rules of the fault breakpoint are constructed.

[0015] Furthermore, the method of constructing a fault breakpoint location determination rule based on the classified fault characteristics includes:

[0016] Based on the classified fault features, calculate the average abnormal feature value of each type of fault feature in the fault scenario;

[0017] Extract the operating data before each line break fault, obtain the fluctuation threshold of each type of fault feature under normal operating conditions, and calculate the corresponding feature mean under normal operating conditions;

[0018] Based on the difference between the mean value of the abnormal features of each type of fault feature and the mean value of the corresponding features, the obtained fluctuation threshold is adjusted to determine the judgment threshold of each type of fault feature;

[0019] According to the judgment threshold of each type of fault feature, the location judgment rule of the fault breakpoint is constructed.

[0020] Furthermore, the fault characteristics include at least three-phase imbalance, voltage drop amplitude, voltage change rate and voltage difference before and after the fault.

[0021] The center location query of the distribution network line based on the topology information of the distribution network line includes:

[0022] Based on the topological information of the distribution network line, a corresponding distribution network line topology image is constructed, and the distribution network line nodes in the image are set;

[0023] The node centrality of each distribution network line node is calculated, and the distribution network line node with the highest node centrality is taken as the center position.

[0024] Furthermore, the calculation of the node centrality of each distribution network line node includes:

[0025] Set the weight parameters for centrality calculation based on the geographical location of the distribution network nodes

[0026] Combined with the set weight parameters, the degree centrality, closeness centrality and betweenness centrality of each distribution network line node are calculated respectively;

[0027] The degree centrality, closeness centrality and betweenness centrality are weighted averaged to obtain the node centrality of each distribution network line node.

[0028] Furthermore, the method of taking the distribution network line node with the highest node centrality as the center position further includes:

[0029] When there are at least two distribution network line nodes with the same highest node centrality, the corresponding fault probability is predicted based on the historical disconnection fault data of the distribution network line area where the corresponding distribution network line node is located;

[0030] The center location is selected based on the probability of failure.

[0031] Furthermore, the abnormality identification of the electrical data at the central position and the search for the fault breakpoint location based on the abnormality identification result and the location judgment rule include:

[0032] Obtaining the fault characteristics and judgment threshold of the fault breakpoint location according to the position judgment rule of the fault breakpoint location;

[0033] The electrical data at the center position is feature extracted, and the extracted feature data is matched with the fault features, and anomaly identification is performed based on the matching results.

[0034] Furthermore, the method of identifying anomalies in the electrical data at the central position and finding the fault breakpoint location based on the anomaly identification result and the location judgment rule further includes:

[0035] When the extracted feature data matches the fault feature, the extracted feature data is compared with the corresponding judgment threshold;

[0036] When each characteristic data exceeds the corresponding judgment threshold, the current center position is determined to be a fault breakpoint.

[0037] Furthermore, the method of identifying anomalies in the electrical data at the central position and finding the fault breakpoint location based on the anomaly identification result and the location judgment rule further includes:

[0038] When there is a characteristic data that does not exceed the corresponding judgment threshold, the current center position is judged to be the back end of the fault breakpoint position;

[0039] Reset the fault breakpoint location search area according to the current center position;

[0040] Perform a central position query in the reset fault breakpoint location search area, and search for the fault breakpoint location again until the fault breakpoint location is obtained.

[0041] The beneficial effects of the present invention are:

[0042] By mining the characteristics of historical disconnection fault data, we can determine the fault characteristics under different fault scenarios and then construct corresponding fault breakpoint location judgment rules based on the fault characteristics. This method no longer relies on a single parameter for fault location and can adapt to the fault breakpoint location search in different fault scenarios, ensuring the accuracy of fault location. Based on the location judgment rules, we use a binary method to quickly locate the fault breakpoint location. First, we query the center location based on topological information. Then, based on the abnormal identification of the center location, we narrow the area where the fault breakpoint location is located, achieving rapid fault breakpoint location search, while ensuring the accuracy of fault location and improving the efficiency of fault breakpoint location search. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below with reference to the accompanying drawings and examples.

[0045] Example:

[0046] Fault breakpoint location search method based on dichotomy, such as Figure 1 Shown, including:

[0047] Obtain the distribution network line where the fault occurred and obtain the corresponding historical disconnection fault data;

[0048] Extract features from historical disconnection fault data and build fault breakpoint location judgment rules based on the extracted fault features;

[0049] Based on the topological information of the distribution network line, the center location of the distribution network line is queried;

[0050] The electrical data at the center position is anomaly identified, and the fault breakpoint location is searched based on the anomaly identification results and position judgment rules to obtain the fault breakpoint location.

[0051] To reduce the computational complexity of locating the fault breakpoint, the specific distribution network line where the fault occurred is first determined based on information from the power monitoring system, fault indicators, or feedback from maintenance personnel. Based on the line name and line number, past disconnection fault data for that distribution network line is retrieved from the power system's historical database. This disconnection fault data includes at least the time of the fault, the location of the fault breakpoint, the fault type, and the electrical parameters of the corresponding monitoring point before and after the disconnection.

[0052] After extracting the historical disconnection fault data, in order to facilitate subsequent feature extraction and analysis, the historical disconnection fault data is preprocessed by missing value processing, outlier processing and standardization processing.

[0053] Considering that line break faults exhibit different fault characteristics in different fault scenarios, even if the fault characteristics are the same, there will be certain differences in the specific values. If a unified judgment rule is used, it will not be able to adapt to different fault scenarios, resulting in fault location errors. Therefore, this embodiment analyzes the line break fault conditions in different fault scenarios based on the acquired historical line break fault data to establish a line break fault location judgment rule. This can adapt to the fault breakpoint location search in different fault scenarios and ensure the accuracy of fault location.

[0054] The feature extraction of historical disconnection fault data and the establishment of a fault breakpoint location determination rule based on the extracted fault features include:

[0055] Based on the occurrence time and cause of the disconnection fault, a fault scenario corresponding to each disconnection fault is constructed;

[0056] Extract features from historical disconnection fault data for each fault scenario and classify the acquired fault features according to their corresponding location information;

[0057] Based on the classified fault characteristics, the location judgment rules of the fault breakpoint are constructed.

[0058] The electrical characteristics of the power system operation are different at different operating times, and the electrical characteristics of different fault causes will also be different. Therefore, based on the occurrence time and fault cause of the line break fault, historical line break fault data is analyzed through a clustering algorithm. According to the similarity between the fault occurrence time and the fault cause, the historical line break fault data is divided into different categories, and each category represents a fault scenario.

[0059] Then, feature extraction is performed on the historical disconnection fault data under each fault scenario, wherein the fault features at least include three-phase imbalance, voltage drop amplitude, voltage change rate, and voltage difference before and after the fault.

[0060] The three-phase unbalance degree in this embodiment mainly refers to the three-phase voltage unbalance degree, which can be calculated by calculating the maximum value, minimum value and average value of the three-phase voltage.

[0061] In order to achieve the mapping relationship between fault characteristics and fault locations, the fault characteristics are classified according to the collection locations of historical line break faults corresponding to the fault characteristics, and the fault characteristics reflected when faults occur at the front end, fault breakpoint and back end of the fault breakpoint of the distribution network line under different fault scenarios are determined.

[0062] After the classification is completed, the fault breakpoint location judgment rules are constructed based on the classified fault characteristics, including:

[0063] Based on the classified fault features, calculate the average abnormal feature value of each type of fault feature in the fault scenario;

[0064] Extract the operating data before each line break fault, obtain the fluctuation threshold of each type of fault feature under normal operating conditions, and calculate the corresponding feature mean under normal operating conditions;

[0065] Based on the difference between the mean value of the abnormal features of each type of fault feature and the mean value of the corresponding features, the obtained fluctuation threshold is adjusted to determine the judgment threshold of each type of fault feature;

[0066] According to the judgment threshold of each type of fault feature, the location judgment rule of the fault breakpoint is constructed.

[0067] Different types of faults are caused by different factors, and their development processes and impacts on system parameters vary. Therefore, even when the same fault characteristics are present, the range and pattern of characteristic value changes will vary depending on the fault mechanism. To ensure the accuracy of fault breakpoint location, we further calculate the characteristic value of each type of fault characteristic under fault conditions, namely the mean abnormal characteristic value, to adjust the threshold for determining whether an anomaly exists.

[0068] Then, based on the operating data before each line break fault, the fluctuation threshold of each type of fault feature under normal operating conditions is obtained. It should be noted that the fault features described in this embodiment are essentially the data features of the power system power parameters in the previous fault scenario. If the same data features appear in the subsequent power system, it does not necessarily mean that a fault has occurred. In order to determine whether the appearance of the data features of the corresponding power parameters is caused by a fault, the corresponding feature values ​​are further calculated based on the power parameters under normal operating conditions, and then a fluctuation threshold is set to determine whether the normal fluctuations in the operation of the power system cause the appearance of fault features.

[0069] When a line break occurs, the circuit structure will change. The distribution network line behind the line break fault location will also show the same fault characteristics. The specific characteristic values ​​will be different from the line break fault location where the fault occurred. However, it is also a line part affected by the fault and has abnormal conditions. In order to distinguish it from the distribution network line in front of the line break fault location that is not affected by the fault, the characteristic mean of each type of fault characteristic under normal operating conditions is calculated and compared with the abnormal characteristic mean of the fault characteristic that is determined to be reflected in the fault state. The difference between the two is determined, and the fluctuation threshold is adjusted accordingly based on the difference between the two, and the judgment threshold of each fault characteristic is set. The different positions here refer to the corresponding relationship with the line break fault location, such as in front of the line break fault location, at the line break fault location, and behind the line break fault location.

[0070] The subsequent location search of the fault breakpoint is directly based on the abnormal situation of the selected location. The set location judgment rule sets the judgment threshold for each fault feature under different fault scenarios. During actual operation, the fault characteristics reflected can be judged according to the electrical data of the selected location, so as to determine the current possible fault scenario, and then compare the reflected fault characteristics with the corresponding judgment threshold to determine the abnormal situation, so as to locate its corresponding position relationship with the fault breakpoint, thereby narrowing the search area of ​​the fault breakpoint and realizing rapid search of the fault breakpoint.

[0071] The location for abnormal selection is directly related to the efficiency of finding the fault breakpoint. In order to optimize the efficiency of finding the disconnection fault location, this embodiment further uses a binary search method to find the disconnection fault location.

[0072] Specifically, based on the topology information of the distribution network line, the center location of the distribution network line is queried, including:

[0073] Based on the topological information of the distribution network line, a corresponding distribution network line topology image is constructed, and the distribution network line nodes in the image are set;

[0074] The node centrality of each distribution network line node is calculated, and the distribution network line node with the highest node centrality is taken as the center position.

[0075] To facilitate calculation, the graph information of the distribution network line is first abstracted into a graph structure, and the line endpoints, such as poles, substations, etc., are set as distribution network line nodes. On this basis, the node centrality of each distribution network line node is calculated to select the center position.

[0076] The calculation of the node centrality of each distribution network line node includes:

[0077] Set the weight parameters for centrality calculation based on the geographical location of the distribution network nodes

[0078] Combined with the set weight parameters, the degree centrality, closeness centrality and betweenness centrality of each distribution network line node are calculated respectively;

[0079] The degree centrality, closeness centrality and betweenness centrality are weighted averaged to obtain the node centrality of each distribution network line node.

[0080] The degree centrality is calculated by the number of edges connected to the distribution network line nodes, and in the constructed image, the edges are the line segments connecting the line endpoints.

[0081] The calculation formula of degree centrality is:

[0082]

[0083] Among them, C D (v) is the degree centrality of the distribution network line node v, d(v) is the degree of the distribution network line node v, that is, the number of edges connected to the distribution network line node v, and n is the number of distribution network line nodes.

[0084] Closeness centrality can be obtained by calculating the shortest path length from the distribution network line node to all other nodes in the graph through algorithms such as breadth-first search.

[0085] The calculation formula for closeness centrality is:

[0086]

[0087] Among them, C D (v) is the closeness centrality of the distribution network line node v, and d(u,v) is the shortest path length from the distribution network line node v to the distribution network node u.

[0088] Betweenness centrality is determined by the number of times a distribution network line node appears in each shortest path between two other distribution network line nodes.

[0089] The calculation formula for betweenness centrality is:

[0090]

[0091] Among them, s and t are two different distribution network line nodes in the figure, σ st is the number of shortest paths from distribution network line node s to distribution network line node t, σ st (v) is the number of shortest paths from distribution network line node s to distribution network line node t that pass through distribution network line node v.

[0092] Finally, the degree centrality, closeness centrality, and betweenness centrality are weighted averaged to obtain the node centrality of each distribution network line node, so that the distribution network line node with the highest node centrality is selected as the center position for subsequent anomaly identification and fault breakpoint location search.

[0093] If more than one distribution network line node with the highest node centrality is obtained when selecting the center position, the corresponding fault probability is predicted based on the historical line break fault data of the distribution network line area where the corresponding distribution network line node is located, and the center position is selected based on the fault probability.

[0094] The distribution network line nodes with high probability of fault occurrence are preferentially selected as the central location to improve the location of the fault breakpoint.

[0095] After determining the center position, obtain the electrical data of the current center position, identify abnormalities in the electrical data at the center position, and locate the fault breakpoint based on the abnormality identification results and location judgment rules, including:

[0096] Obtaining the fault characteristics and judgment threshold of the fault breakpoint location according to the position judgment rule of the fault breakpoint location;

[0097] The electrical data at the center position is feature extracted, and the extracted feature data is matched with the fault features, and anomaly identification is performed based on the matching results.

[0098] According to the established fault breakpoint location judgment rules, the fault characteristics that the fault breakpoint location should have can be clearly identified, and then the electrical data of the center position is extracted and matched with the fault characteristics to determine whether the current center position is in the fault impact area. If it is determined to be in the fault impact area, the corresponding fault scenario can also be determined based on the type of matched fault characteristics, etc., to determine the judgment threshold required for subsequent location search.

[0099] Therefore, when the extracted feature data matches the fault feature, the extracted feature data is further compared with the corresponding judgment threshold;

[0100] When each characteristic data exceeds the corresponding judgment threshold, the current center position is determined to be a fault breakpoint.

[0101] The fault characteristics at the fault breakpoint position are the most obvious. Therefore, if all characteristic data exceed the judgment threshold corresponding to the fault breakpoint position, the current position can be determined to be the fault breakpoint.

[0102] The electrical data behind the fault breakpoint is affected by the fault and will also show a certain degree of abnormality, but the degree of abnormality is different from the position of the fault breakpoint. That is, the fault characteristics can be matched, but not all fault characteristics exceed the corresponding judgment threshold.

[0103] Therefore, when there is a feature data that does not exceed the corresponding judgment threshold, the current center position is judged to be the back end of the fault breakpoint position;

[0104] Reset the fault breakpoint location search area according to the current center position;

[0105] Perform a central position query in the reset fault breakpoint location search area, and search for the fault breakpoint location again until the fault breakpoint location is obtained.

[0106] After determining that the currently selected center position is the rear end of the fault breakpoint, the fault breakpoint location search area can be narrowed from the entire distribution network line to the area from the starting point of the distribution network line to the currently selected center position.

[0107] Starting from this reset fault breakpoint location search area, repeat the center position query and center position anomaly identification until the fault breakpoint location is located.

[0108] The above processing method is mainly aimed at identifying abnormalities at the center location. However, if the electrical data of the initially selected center location indicates that the current location is in normal operation and is not affected by the fault, that is, no fault characteristics are present, or the fault characteristics that do appear do not exceed the corresponding judgment threshold for any fault scenario, then the selected center location can be determined to be the front end of the fault breakpoint. At this time, the fault breakpoint location search area can be narrowed from the entire distribution network line to the area from the currently selected center location to the end of the distribution network line.

[0109] The embodiment described above is only a preferred solution of the present invention and does not limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solution described in the claims.

Claims

1. A fault breakpoint location search method based on dichotomy, characterized in that: include: Obtain the distribution network line where the fault occurred and obtain the corresponding historical disconnection fault data; Extract features from historical disconnection fault data and build fault breakpoint location judgment rules based on the extracted fault features; Based on the topological information of the distribution network line, the center location of the distribution network line is queried; The electrical data at the center position is anomaly identified, and the fault breakpoint location is searched based on the anomaly identification results and position judgment rules to obtain the fault breakpoint location.

2. The method for finding the fault breakpoint location based on the dichotomy method according to claim 1, characterized in that: The feature extraction of historical disconnection fault data and the establishment of a fault breakpoint location determination rule based on the extracted fault features include: Based on the occurrence time and cause of the disconnection fault, the corresponding fault scenario for each disconnection fault is constructed; the historical disconnection fault data for each fault scenario is extracted, and the acquired fault features are classified according to the corresponding location information of the fault features; Based on the classified fault characteristics, the location judgment rules of the fault breakpoint are constructed.

3. The method for finding the fault breakpoint location based on the dichotomy method according to claim 2, characterized in that: The method of constructing a fault breakpoint location determination rule based on the classified fault characteristics includes: Based on the classified fault features, calculate the average abnormal feature value of each type of fault feature in the fault scenario; Extract the operating data before each line break fault, obtain the fluctuation threshold of each type of fault feature under normal operating conditions, and calculate the corresponding feature mean under normal operating conditions; Based on the difference between the mean value of the abnormal features of each type of fault feature and the mean value of the corresponding features, the obtained fluctuation threshold is adjusted to determine the judgment threshold of each type of fault feature; According to the judgment threshold of each type of fault feature, the location judgment rule of the fault breakpoint is constructed.

4. The method for finding the fault breakpoint location based on the dichotomy method according to claim 2, characterized in that: The fault characteristics include at least three-phase imbalance, voltage drop amplitude, voltage variation and voltage difference before and after the fault.

5. The method for finding the fault breakpoint location based on the dichotomy method according to claim 1, characterized in that: The center location query of the distribution network line based on the topology information of the distribution network line includes: Based on the topological information of the distribution network line, a corresponding distribution network line topology image is constructed, and the distribution network line nodes in the image are set; The node centrality of each distribution network line node is calculated, and the distribution network line node with the highest node centrality is taken as the center position.

6. The method for finding the fault breakpoint location based on the dichotomy method according to claim 5, characterized in that: The calculation of the node centrality of each distribution network line node includes: Set the weight parameters for centrality calculation based on the geographical location of the distribution network nodes Combined with the set weight parameters, the degree centrality, closeness centrality and betweenness centrality of each distribution network line node are calculated respectively; The degree centrality, closeness centrality and betweenness centrality are weighted averaged to obtain the node centrality of each distribution network line node.

7. The method for finding the fault breakpoint location based on the dichotomy method according to claim 5, characterized in that: The distribution network line node with the highest node centrality as the center position also includes: When there are at least two distribution network line nodes with the same highest node centrality, the corresponding fault probability is predicted based on the historical disconnection fault data of the distribution network line area where the corresponding distribution network line node is located; The center location is selected based on the probability of failure.

8. The method for finding the fault breakpoint location based on the dichotomy method according to claim 1, characterized in that: The abnormality identification of the electrical data at the central position and the search for the fault breakpoint location based on the abnormality identification result and the location judgment rule include: The fault characteristics and judgment threshold of the fault breakpoint location are obtained according to the position judgment rule of the fault breakpoint location; the electrical data at the center position is feature extracted, and the extracted feature data is matched with the fault characteristics, and anomaly identification is performed based on the matching results.

9. The method for finding the fault breakpoint location based on the dichotomy method according to claim 8, characterized in that: The method of identifying anomalies in the electrical data at the central position and finding the fault breakpoint location based on the anomaly identification result and the location judgment rule further includes: When the extracted feature data matches the fault feature, the extracted feature data is compared with the corresponding judgment threshold; When each characteristic data exceeds the corresponding judgment threshold, the current center position is determined to be a fault breakpoint.

10. The method for finding the fault breakpoint location based on the dichotomy method according to claim 9, characterized in that: The method of identifying anomalies in the electrical data at the central position and finding the fault breakpoint location based on the anomaly identification result and the location judgment rule further includes: When there is a characteristic data that does not exceed the corresponding judgment threshold, the current center position is judged to be the back end of the fault breakpoint position; Reset the fault breakpoint location search area according to the current center position; Perform a central position query in the reset fault breakpoint location search area, and search for the fault breakpoint location again until the fault breakpoint location is obtained.

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