A power distribution network single-phase ground fault research and disposal method and system

Abstract

The application discloses a power distribution network single-phase grounding fault research and disposal method and system, and the method comprises the following steps: acquiring a line selection alarm signal and a line selection result of a small-current grounding line selection device in a station; calculating a zero sequence current change of all out-station terminals of a corresponding line according to the line selection result; if the line topology structure is checked, a new line topology structure is obtained by replacing a specified terminal in the line topology structure with a conductor; the out-station terminals are hierarchically clustered according to the zero sequence current change, a class with a larger arithmetic mean in the clustering result is a fault class, and a class with a smaller arithmetic mean in the clustering result is a normal class; a fault point is marked in the new line topology structure according to the out-station terminals corresponding to the fault class and the normal class; the fault point is isolated, if the line selection alarm signal is not restored after all the fault points are isolated, the above steps are iteratively executed until the line selection alarm signal is restored. The application can accurately dispose the single-phase grounding fault by iteratively clustering in combination with the fault restoration condition.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power distribution network, in particular to a power distribution network single-phase grounding fault research and disposal method and system. BACKGROUND

[0002] The 10kV outgoing line of the power distribution network is a non-grounding system. When a single-phase grounding fault occurs, it does not affect the reliability of user power supply and generally does not cause line tripping. However, single-phase grounding not only affects the normal power supply of users, but also may cause overvoltage, damage equipment, cause forest fires, and even develop into an inter-phase short-circuit fault, thereby causing the outgoing line to trip and affecting the economy of power grid operation.

[0003] In the research and disposal of 10kV outgoing line grounding faults, it is necessary to complete the positioning of the grounding fault outgoing line and the positioning of the fault between outgoing line segments. At present, the station transient method small current grounding line selection device can achieve an accuracy of more than 97.4%, and the problem of inaccurate station line selection has been well solved. For the station external outgoing line fault section, generally, the dispatcher receives fault information by telephone or checks the small current grounding alarm signal in the power distribution automation master station alarm window, enters the zero sequence current display interface or bus grounding fault auxiliary disposal interface to check the zero sequence current change amount sorting, and then manually positions the fault by switch test pulling, and then arranges maintenance personnel to perform line inspection.

[0004] The current disposal method has the following problems: the station small current grounding line selection device does not cooperate with the station external terminal, resulting in difficulty in fault positioning; fault disposal mainly relies on manual and experience, the fault judgment accuracy is low, the disposal time is long, and the automation level is low; the fault cannot be responded in time. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a power distribution network single-phase grounding fault research and disposal method and system, which collects the alarm signals of the station transient small current grounding line selection device and the zero sequence current and grounding alarm signals of the station external terminal, cooperates the station internal and external information in the power distribution automation master station, completes the small current grounding line selection and station external section selection, and performs fault positioning and fault isolation through the power distribution automation master station, in view of the above problems of the prior art.

[0006] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0007] A power distribution network single-phase grounding fault research and disposal method, comprising the following steps:

[0008] Obtaining the line selection alarm signal and line selection result of the station small current grounding line selection device;

[0009] According to the line selection result, calculating the zero sequence current change amount of all station external terminals corresponding to the line;

[0010] The line topology structure is checked, if the checking is passed, a conductor is used to replace a specified terminal in the line topology structure, and a new line topology structure is obtained;

[0011] The off-site terminals are hierarchically clustered according to the zero sequence current variation, the classes with the arithmetic mean of the zero sequence current variation greater than the preset threshold are classified as fault classes, and the classes with the arithmetic mean of the zero sequence current variation less than the preset threshold are classified as normal classes;

[0012] The off-site terminals corresponding to the fault classes and the normal classes are marked as fault points in the new line topology structure;

[0013] The fault points are isolated, if the line selection alarm signal is not restored after all the fault points are isolated, the above steps are iteratively executed until the line selection alarm signal is restored.

[0014] Further, after obtaining the line selection alarm signal and the line selection result of the in-station small current grounding line selection device, the method comprises:

[0015] The grounding type information is obtained, if it is instantaneous grounding, the process is ended and exited, if it is not instantaneous grounding, the step of calculating the zero sequence current variation of all off-site terminals of the corresponding line according to the line selection result is executed.

[0016] Further, the specified terminal comprises a non-automatic switch, an offline terminal, a fault terminal and an abnormal terminal.

[0017] Further, when the off-site terminals are hierarchically clustered according to the zero sequence current variation, the method comprises:

[0018] The zero sequence current variation is sorted, and the difference between adjacent elements in the sequence is calculated;

[0019] The off-site terminals corresponding to the minimum difference of the zero sequence current variation are classified into the same class;

[0020] The zero sequence current variation of the off-site terminal that has completed clustering is removed from the sequence, the arithmetic mean of the zero sequence current variation of the clustered off-site terminal is calculated and added to the sequence;

[0021] If the number of elements in the sequence is greater than a specified number, the above steps are repeated until the number of elements in the sequence is less than or equal to the specified number.

[0022] Further, after obtaining the new line topology structure, the method comprises: if the new line topology structure does not contain any branch, a virtual terminal is generated at the end of the line, and the virtual zero sequence current value of the virtual terminal is 0.

[0023] Further, before the zero sequence current variation is layered and clustered, the method comprises: if the number of terminals in the new line topology structure is less than the target number, marking the line ends of all terminals as fault points, and performing the step of isolating the fault points.

[0024] Further, when marking the fault points in the new line topology structure according to the off-site terminals corresponding to the fault class and the normal class, the method comprises:

[0025] If there is no normal class terminal between the fault class terminals, the fault terminals are considered adjacent, and the lines of each adjacent fault terminal are colored with a fault color;

[0026] If there is a normal class terminal between the lines colored with the fault color, the line of the normal class terminal is colored with the fault color;

[0027] If there are two normal class terminals between the lines colored with the fault color, the line of the normal class terminal is not colored with the fault color;

[0028] The ends of each colored part are marked as fault points.

[0029] Further, when isolating the fault points, the method comprises:

[0030] The fault points are sequentially isolated from the branch to the middle section starting from the topology end of the line topology structure, and when isolating the fault point at the topology end, the switch before the fault point is opened, and when isolating the fault point in the middle section of the line, all the switches after the end of the fault point are opened before the switch before the fault point is opened.

[0031] Further, when sequentially isolating the fault points from the outside to the inside starting from the topology end of the line topology structure, the method comprises:

[0032] If the fault points in the line topology structure are single, after isolating the fault point, it is checked whether the line selection alarm signal is restored, and if yes, the process is ended and exited, and if not, the steps of acquiring the line selection alarm signal and the line selection result of the station small current grounding line selection device and the subsequent steps are re-executed;

[0033] If the fault points in the line topology structure are multiple, after isolating each fault point, it is checked whether the line selection alarm signal is restored, and if yes, the process is ended and exited, and if not, the subsequent fault points are continuously isolated, and if all the fault points are isolated, the line selection alarm signal is still not restored, and then the steps of acquiring the line selection alarm signal and the line selection result of the station small current grounding line selection device and the subsequent steps are re-executed.

[0034] The application also provides a power distribution network single-phase grounding fault research and disposal system, comprising a station small current grounding line selection device and a power distribution automation master station, wherein:

[0035] The station small current grounding line selection device is used for triggering an alarm, and sending a line selection alarm signal and a line selection result to a power distribution automation master station through a data gateway;

[0036] The power distribution automation master station is used for:

[0037] obtaining a line selection alarm signal and a line selection result of the station small current grounding line selection device;

[0038] According to the line selection result, the zero sequence current change amount of all stations outside the corresponding line is calculated.

[0039] The line topology structure is checked, and if the check passes, a new line topology structure is obtained by replacing the specified terminal in the line topology structure with a conductor.

[0040] According to the zero sequence current change amount, the stations outside are hierarchically clustered, and the classes with an arithmetic mean of the zero sequence current change amount greater than a preset threshold are classified as fault classes, and the classes with an arithmetic mean of the zero sequence current change amount less than the preset threshold are classified as normal classes.

[0041] According to the stations outside corresponding to the fault classes and the normal classes, the fault points are marked in the new line topology structure.

[0042] The fault points are isolated, and if the line selection alarm signal is not restored after all the fault points are isolated, the above steps are iteratively executed until the line selection alarm signal is restored.

[0043] Compared with the prior art, the advantages of the present application are:

[0044] After obtaining the line selection result of the station small current grounding line selection device, the present application collects the zero sequence current of the power distribution automation terminal outside the station to locate the specific fault position, realizes the cooperation of the devices inside and outside the station, and according to the zero sequence current change amount, the stations outside are hierarchically clustered without setting a threshold, which can adapt to different line parameters.

[0045] The present application combines hierarchical clustering with automatic generation of topology, can filter out abnormal data, and has certain fault tolerance performance. In addition, the hierarchical clustering algorithm provided by the present application iterates multiple times according to the fault isolation, and realizes accurate positioning of the fault points. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 A brief flowchart of the ground fault research and judgment in the embodiment of the present application.

[0047] Figure 2 A detailed flowchart of the ground fault research and judgment in the embodiment of the present application.

[0048] Figure 3 A 110 / 10kV outgoing line simulation model topology graph provided in the embodiment of the present application.

[0049] Figure 4 A single-phase ground fault simulation zero sequence current distribution diagram for an embodiment of the present application.

[0050] Figure 5 A hierarchical clustering diagram according to a zero sequence current change amount for an embodiment of the present application.

[0051] Figure 6 A single-phase ground fault simulation fault line coloring diagram for the first time of an embodiment of the present application.

[0052] Figure 7 A brief flowchart of ground fault disposal for an embodiment of the present application.

[0053] Figure 8 A single-phase ground fault simulation fault line coloring diagram for the second time of an embodiment of the present application. DETAILED DESCRIPTION

[0054] The present application is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present application is not limited thereby.

[0055] Embodiment One

[0056] The present embodiment proposes a power distribution network single-phase ground fault judgment and disposal method, applied to a power distribution network provided with a station small current grounding line selection device and a power distribution automation master station, such as Figure 1 and Figure 2 as shown, comprising the following steps:

[0057] Fault judgment, including:

[0058] S1, the station small current grounding line selection device triggers an alarm, and uploads the line selection alarm signal and line selection result to the power distribution automation master station through a data gateway;

[0059] S2, the power distribution automation master station acquires the line selection alarm signal and line selection result of the station small current grounding line selection device; according to the line selection result, calculates the zero sequence current change amount of all out-of-station terminals corresponding to the line;

[0060] S3, the power distribution automation master station checks the line topology structure, and if the check is wrong, ends and exits;

[0061] S4, if the check is passed, the power distribution automation master station replaces the designated terminal in the line topology structure with a lead, to obtain a new line topology structure;

[0062] S5, the power distribution automation master station performs hierarchical clustering on the out-of-station terminals according to the zero sequence current variation, and divides a class with a larger arithmetic mean of the zero sequence current variation in the clustering result into a fault class, and divides a class with a smaller arithmetic mean of the zero sequence current variation in the clustering result into a normal class;

[0063] S6, the power distribution automation master station marks a fault point in a new line topology structure according to the out-of-station terminals corresponding to the fault class and the normal class, so as to perform fault positioning;

[0064] Fault handling, including:

[0065] S7, the fault point is isolated by trial pulling, if the line selection alarm signal is not restored after all fault points are isolated, the step S1 is jumped to perform next iteration, until the line selection alarm signal is restored, to realize self-healing after isolation.

[0066] The steps will be described in detail in combination with specific examples.

[0067] According to Figure 3 The simulation model is built as shown in the system, and the parameter values of the system are shown in Table 1:

[0068] Table 1 Parameter values of simulation model

[0069]

[0070]

[0071] Figure 4 The zero sequence current distribution under the single-phase ground fault of node 2 and node 5 in the simulation model is given.

[0072] In step S2 of the embodiment, after obtaining the line selection alarm signal and the line selection result of the in-station small current grounding line selection device, the step includes:

[0073] The grounding type information is obtained, if it is instantaneous grounding, it is ended and exited, if it is not instantaneous grounding, the step of calculating the zero sequence current variation of all out-of-station terminals of the corresponding line is executed according to the line selection result. After the power distribution automation master station obtains the line selection alarm signal and the line selection result of the in-station small current grounding line selection device, how to continue to obtain the grounding type information is well known to those skilled in the art, for example, the current and voltage waveforms at the time of fault can be recorded, the nature of the fault can be inferred by analyzing these waveforms, or a hardware device can be used to analyze the fault type, or the characteristics of the grounding fault can be analyzed in real time by continuously monitoring related parameters, the embodiment does not limit this, and will not be described in detail.

[0074] In step S2 of the embodiment, according to the selected line result, the zero sequence current variation of all off-site terminals corresponding to the line is calculated, specifically, the zero sequence current telemetry and ground alarm signal of all switches corresponding to the line are summed up, and the zero sequence current telemetry and ground alarm signal before the fault are recorded, and the zero sequence current variation is obtained by calculating the difference between the zero sequence current telemetry before and after the fault. As shown in FIG. 6, the zero sequence current variation of all off-site terminals is: 5.83 for outgoing line 1, 4 for 301, 1.81 for 302, 0.07 for 303, 1.83 for 304, 0.06 for 305, and 0.07 for 306. Figure 4

[0075] In step S3 of the embodiment, the distribution automation master station checks the line topology structure and coloring, and the specific implementation process of the checking is well known to those skilled in the art and is not the focus of the present scheme, and thus will not be described in detail in the embodiment. If the checking is wrong, the line topology structure is automatically refreshed, and then the checking is performed again. If the checking is still wrong, the research and judgment is ended.

[0076] In step S4 of the embodiment, when the distribution automation master station replaces the specified terminal in the line topology structure with a lead, the specified terminal includes a non-automatic switch, an offline terminal, a fault terminal and an abnormal terminal. The non-automatic switch, the offline terminal, the fault terminal and the abnormal terminal can be obtained by analyzing the relevant information when the zero sequence current telemetry and the ground alarm signal of all switches corresponding to the line are summed up. The specific data analysis process is well known to those skilled in the art and is not the focus of the present scheme, and thus will not be described in detail in the embodiment.

[0077] After obtaining the new line topology structure, the number of terminals in the new line topology structure is counted. If the number is less than the target number, all terminal line ends are marked as fault points, and step S7 for fault disposal is jumped to. In the embodiment, the target number is 3, that is, when the number of terminals in the new line topology structure is 2, the step for fault disposal is directly entered.

[0078] Further, in the case where the number of terminals in the new line topology structure is greater than or equal to the target number, it is judged whether the new line topology structure contains branches. If it does not contain any branch, a virtual terminal is generated at the end of the line, and the virtual zero sequence current value of the virtual terminal is 0.

[0079] In step S5 of the embodiment, the hierarchical clustering method is used to cluster the off-site terminals to obtain two classes, without setting a threshold value, which can adapt to various line parameter scenarios. Specifically, when the off-site terminals are hierarchically clustered according to the zero sequence current variation, it includes:

[0080] S51, the zero sequence current variation is sorted, and the difference between adjacent elements in the sequence is calculated.

[0081] ​S52, select the minimum difference, and divide the station outside terminal corresponding to the zero sequence current variation forming the minimum difference into a class;

[0082] S53, remove the zero sequence current variation of the station outside terminal completing clustering from the sequence, calculate the arithmetic mean of the zero sequence current variation of the clustered station outside terminal and add it to the sequence;

[0083] S54, if the number of elements in the sequence is greater than a specified number, repeat steps S51 to S53 until the number of elements in the sequence is less than or equal to the specified number.

[0084] The specified number in this embodiment is 2. According to the foregoing description, the zero sequence current variation of each station outside terminal is: 5.83 for the outgoing line 1, 4 for 301, 1.81 for 302, 0.07 for 303, 1.83 for 304, 0.06 for 305, and 0.07 for 306. The specific clustering process is as follows: Figure 5 As shown in the figure, the process is as follows:

[0085] First round of clustering:

[0086] The zero sequence current variation is sorted in ascending order, and the result is: 0.06 (305), 0.07 (306), 0.07 (303), 1.81 (302), 1.83 (304), 4 (301), 5.83 (outgoing line 1), wherein the bracket indicates the station outside terminal corresponding to the zero sequence current variation;

[0087] The difference between adjacent elements in the sequence is calculated, and the result is: 0.01, 0, 1.74, 0.02, 2.17, 1.83;

[0088] The station outside terminal corresponding to the zero sequence current variation forming the minimum difference is divided into a class, i.e. the station outside terminals 306 and 303 corresponding to the difference 0 are divided into a class;

[0089] The zero sequence current 0.07 (306), 0.07 (303) of the station outside terminal completing clustering is removed from the sequence, the arithmetic mean of the zero sequence current variation of the clustered station outside terminals 306 and 303 is calculated to obtain 0.07, and the sequence is added to obtain: 0.06 (305), 1.81 (302), 1.83 (304), 4 (301), 5.83 (outgoing line 1), 0.07 (306, 303). At this time, the number of elements in the sequence is 6, so the second round of clustering is performed;

[0090] Second round of clustering:

[0091] Sort the zero sequence current variation in ascending order to get: 0.06 (305), 0.07 (306, 303), 1.81 (302), 1.83 (304), 4 (301), 5.83 (outgoing line 1);

[0092] Calculate the difference between adjacent elements in the sequence to get: 0.01, 1.74, 0.02, 2.17, 1.83;

[0093] Classify the off-site terminals corresponding to the zero sequence current variation that forms the smallest difference, that is, classify the off-site terminals 305, 306, 303 corresponding to the difference 0.02 into a class;

[0094] Remove the zero sequence currents 0.06 (305), 0.07 (306, 303) of the off-site terminals that have completed clustering from the sequence, calculate the arithmetic mean of the zero sequence current variations of the clustered off-site terminals 305, 306, 303 to get 0.068, and add it to the sequence to get: 1.81 (302), 1.83 (304), 4 (301), 5.83 (outgoing line 1), 0.068 (305, 306, 303), at this time the number of elements in the sequence is 5, so the third round of clustering is performed;

[0095] Third round of clustering:

[0096] Sort the zero sequence current variation in ascending order to get: 0.068 (305, 306, 303), 1.81 (302), 1.83 (304), 4 (301), 5.83 (outgoing line 1);

[0097] Calculate the difference between adjacent elements in the sequence to get: 1.74, 0.02, 2.17, 1.83;

[0098] Classify the off-site terminals corresponding to the zero sequence current variation that forms the smallest difference, that is, classify the off-site terminals 302, 304 corresponding to the difference 0.02 into a class;

[0099] Remove the zero sequence currents 1.81 (302), 1.83 (304) of the off-site terminals that have completed clustering from the sequence, calculate the arithmetic mean of the zero sequence current variations of the clustered off-site terminals 302, 304 to get 1.82, and add it to the sequence to get: 0.068 (305, 306, 303), 4 (301), 5.83 (outgoing line 1), 1.82 (302, 304), at this time the number of elements in the sequence is 4, so the fourth round of clustering is performed;

[0100] Fourth round of clustering:

[0101] Sort the zero sequence current variation in ascending order to obtain: 0.068 (305, 306, 303), 1.82 (302, 304), 4 (301), 5.83 (outgoing line 1);

[0102] Calculate the difference between adjacent elements in the sequence to obtain: 1.75, 2.18, 1.83;

[0103] Classify the off-site terminals corresponding to the zero sequence current variation that forms the smallest difference, i.e., classify the off-site terminals 305, 306, 303, 302, 304 corresponding to the difference 1.75 into one class;

[0104] Remove the zero sequence current 0.067 (305, 306, 303), 1.82 (302, 304) of the off-site terminals that have completed clustering from the sequence, calculate the arithmetic mean of the zero sequence current variation of the clustered off-site terminals 305, 306, 303, 302, 304 to obtain 0.932, and add it to the sequence to obtain: 4 (301), 5.83 (outgoing line 1), 0.932 (305, 306, 303, 302, 304). At this time, the number of elements in the sequence is 3, so the fifth round of clustering is performed;

[0105] Fifth round of clustering:

[0106] Sort the zero sequence current variation in ascending order to obtain: 0.932 (305, 306, 303, 302, 304), 4 (301), 5.83 (outgoing line 1);

[0107] Calculate the difference between adjacent elements in the sequence to obtain: 3.068, 1.83;

[0108] Classify the off-site terminals corresponding to the zero sequence current variation that forms the smallest difference, i.e., classify the off-site terminals 301, outgoing line 1 corresponding to the difference 1.83 into one class;

[0109] Remove the zero sequence current 4 (301), 5.83 (outgoing line 1) of the off-site terminals that have completed clustering from the sequence, calculate the arithmetic mean of the zero sequence current variation of the clustered off-site terminals 301, outgoing line 1 to obtain 4.915, and add it to the sequence to obtain: 0.932 (305, 306, 303, 302, 304), 4.915 (301, outgoing line 1). At this time, the number of elements in the sequence is 2, and the clustering is complete.

[0110] Since the arithmetic mean of the zero sequence current variation of the off-site terminals 305, 306, 303, 302, 304 is the smaller value 0.932, and the arithmetic mean of the zero sequence current variation of the off-site terminals 301, outgoing line 1 is the larger value 4.915, therefore, through the above steps, the fault class terminals are obtained as outgoing line 1 and 301.

[0111] In step S6 of the embodiment, when marking the fault points in the new line topology structure according to the out-of-station terminals corresponding to the fault class and the normal class, the following is included:

[0112] S61, if there is no normal class terminal between the fault class terminals, the fault terminals are considered adjacent, and the lines of each adjacent fault terminal are colored with the fault color;

[0113] S62, if there is a normal class terminal between the lines colored with the fault color, the terminal data is considered abnormal, the line of the normal class terminal is colored with the fault color, and thus the line between the colored parts at both ends is colored with the fault color;

[0114] S63, if there are two normal class terminals between the lines colored with the fault color, the data of the two terminals is considered normal, and the lines of the two normal class terminals are not colored with the fault color, and thus no coloring is performed on the middle part;

[0115] S64, the terminal of each colored part is marked as a fault point.

[0116] Through the above steps, the coloring result is as shown in Figure 6 It can be seen that the fault location this time is to the terminal of 301, i.e., node 2.

[0117] In step S7 of the embodiment, when isolating the fault points, the branch line fault handling is performed first, and then the middle section fault handling is performed, and the following is included:

[0118] The fault points are isolated from the branch line to the middle section in sequence from the topological terminal of the line topology structure, the switch before the fault point is pulled open when isolating the fault point at the topological terminal, and the switch after the fault point at the middle section of the line is pulled open before the switch before the fault point is pulled open when isolating the fault point at the middle section of the line.

[0119] Further, when isolating the fault points from the outside to the inside in sequence from the topological terminal of the line topology structure, the following is included:

[0120] If the fault points in the line topology structure are single, after isolating the fault point, it is checked whether the line selection alarm signal is restored, yes, then the process is ended and exited, and no, then the steps of acquiring the line selection alarm signal and the line selection result of the station small current grounding line selection device and the subsequent steps are re-executed;

[0121] If the fault points in the line topology structure are multiple, after isolating each fault point, it is checked whether the line selection alarm signal is restored, yes, then the process is ended and exited, and no, then the subsequent fault points are continuously isolated, and if all the fault points are isolated, the line selection alarm signal is still not restored, then the steps of acquiring the line selection alarm signal and the line selection result of the station small current grounding line selection device and the subsequent steps are re-executed.

[0122] As shown in Figure 7As shown, the step S7 of the embodiment is specifically as follows:

[0123] Step 1: Isolate the fault point at the end of the topology preferentially, and open the switch before the fault point; that is, open 301. If the fault line selection alarm signal is not returned, exclude 301 and re-execute S1 to S6. When re-executing S1 to S6, exclude the related data of 301 in steps S2 and S4. The execution result is that Out1, 302 and 304 are fault types, and the topology coloring is as shown in the figure. Figure 8 As shown, the branch line has no fault point.

[0124] Step 2: Since the branch line of the new line topology structure has no fault point, isolate the fault point in the middle of the line directly, and open all the switches after the fault point and then open the switch before the fault point; that is, open 306, 305 and 304 in turn.

[0125] Step 3: If all the faults are isolated, and the ground fault signal is returned, enter the line self-healing.

[0126] Embodiment two

[0127] The embodiment provides a power distribution network single-phase ground fault research and disposal system, comprising a station small-current ground line selection device and a power distribution automation master station, wherein:

[0128] The station small-current ground line selection device is used for triggering an alarm, and uploading a line selection alarm signal and a line selection result to the power distribution automation master station through a data gateway.

[0129] The power distribution automation master station is used for:

[0130] obtaining the line selection alarm signal and the line selection result of the station small-current ground line selection device;

[0131] calculating a zero sequence current change amount of all station-out terminals corresponding to a line according to the line selection result;

[0132] checking a line topology structure, if the checking is passed, replacing a designated terminal in the line topology structure with a wire to obtain a new line topology structure;

[0133] performing hierarchical clustering on the station-out terminals according to the zero sequence current change amount, and dividing a class in which an arithmetic average of the zero sequence current change amount is greater than a preset threshold value into a fault class, and dividing a class in which the arithmetic average of the zero sequence current change amount is less than the preset threshold value into a normal class;

[0134] marking a fault point in the new line topology structure according to station-out terminals corresponding to the fault class and the normal class;

[0135] The fault points are isolated, if the line selection alarm signal is not returned after all fault points are isolated, the above steps are iteratively executed until the line selection alarm signal is returned.

[0136] In summary, the application provides a power distribution network single-phase grounding fault judgment and disposal method and system, during fault judgment, the topology is updated by identifying terminal conditions and abnormal data, the zero sequence current change is calculated by collecting zero sequence current during fault, the zero sequence current change is quickly clustered by using hierarchical clustering algorithm, and the fault point is located according to the topology structure. During fault disposal, branch fault disposal is performed first, then middle segment fault disposal is performed, and iterative clustering is performed combined with fault return conditions, so that single-phase grounding fault is accurately disposed. Overall, the following advantages are obtained:

[0137] (1) The hierarchical clustering algorithm is used to cluster the zero sequence current, without setting a threshold, and can adapt to various line parameter scenes;

[0138] (2) The topology is updated in time according to terminal offline, abnormality and the like, the fault is determined combined with the topology structure and the zero sequence current clustering result, and the determination is more accurate;

[0139] (3) The iterative clustering is performed according to the fault disposal result, the multiple-point single-phase grounding fault can be processed, and the application has certain fault tolerance.

[0140] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer readable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer usable program codes. The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device for implementing the functions described in the flowcharts and / or block diagrams. Figure 1 one flow or multiple flows and / or blocks Figure 1apparatuses that implement the functions specified in the flowchart or flowchart blocks. These computer program instructions can also be loaded onto a computer or other programmable data processing devices to cause a series of operational steps to be performed on the computer or other programmable data processing devices to generate computer-implemented processes such that the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in the flowchart or flowchart blocks. Figure 1 flowchart or flowchart blocks Figure 1 flowchart or flowchart blocks These computer program instructions can also be loaded onto a computer or other programmable data processing devices to cause a series of operational steps to be performed on the computer or other programmable data processing devices to generate computer-implemented processes such that the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in the flowchart or flowchart blocks. Figure 1 flowchart or flowchart blocks Figure 1 flowchart or flowchart blocks

[0141] The above description is only the preferred embodiment of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical solutions falling within the concept of the present application shall be considered as falling within the protection scope of the present application. It should be noted that, for ordinary skilled in the art, some improvements and refinements without departing from the principles of the present application shall also be considered as falling within the protection scope of the present application.

Claims

1. A method for judging and disposing single-phase ground fault of a power distribution network, characterized in that, The method comprises the following steps: obtaining the line selection alarm signal and the line selection result of the small current grounding line selection device in the station; calculating the zero sequence current variation of all off-station terminals corresponding to the line according to the line selection result; checking the line topology structure, and replacing the specified terminal in the line topology structure with a conductor to obtain a new line topology structure if the checking is passed; performing hierarchical clustering on the off-station terminals according to the zero sequence current variation to obtain a clustering result containing two classes, and dividing the class with a larger arithmetic mean of the zero sequence current variation into a fault class and the class with a smaller arithmetic mean of the zero sequence current variation into a normal class; marking the fault points in the new line topology structure according to the off-station terminals corresponding to the fault class and the normal class; isolating the fault points, and iteratively performing the above steps until the line selection alarm signal is restored if the line selection alarm signal is not restored after isolating all the fault points.

2. The power distribution network single-phase earth fault analysis and disposal method according to claim 1, characterized in that, After obtaining the line selection alarm signal and the line selection result of the small current grounding line selection device in the station, the method comprises the following steps: obtaining the grounding type information, ending and exiting if it is instantaneous grounding, and performing the step of calculating the zero sequence current variation of all off-station terminals corresponding to the line according to the line selection result if it is not instantaneous grounding.

3. The power distribution network single-phase earth fault diagnosis and disposal method according to claim 1, characterized in that, The specified terminal comprises a non-automatic switch, an offline terminal, a fault terminal and an abnormal terminal.

4. The power distribution network single-phase earth fault diagnosis and disposal method according to claim 1, characterized in that, When performing hierarchical clustering on the off-station terminals according to the zero sequence current variation, the method comprises the following steps: sorting the zero sequence current variation, and calculating the difference between adjacent elements in the sequence; dividing the off-station terminals corresponding to the minimum difference of the zero sequence current variation into the same class; removing the zero sequence current variation of the off-station terminals that have been clustered from the sequence, calculating the arithmetic mean of the zero sequence current variation of the clustered off-station terminals and adding it to the sequence; if the number of elements in the sequence is greater than a specified number, repeating the above steps until the number of elements in the sequence is less than or equal to the specified number.

5. The power distribution network single-phase earth fault diagnosis and disposal method according to claim 1, characterized in that, After obtaining the new line topology structure, the method comprises the following steps: if the new line topology structure does not contain any branch, generating a virtual terminal at the end of the line, and the virtual zero sequence current value of the virtual terminal is 0.

6. The power distribution network single-phase earth fault diagnosis and disposal method according to claim 1, characterized in that, Before performing hierarchical clustering on the zero sequence current variation, the method comprises the following steps: if the number of terminals in the new line topology structure is less than a target number, marking the terminals at the end of the line as fault points, and performing the step of isolating the fault points.

7. The power distribution network single-phase earth fault diagnosis and disposal method according to claim 1, characterized in that, When marking the fault points in the new line topology structure according to the off-station terminals corresponding to the fault class and the normal class, the method comprises the following steps: if there is no normal class terminal between the fault class terminals, considering the fault terminals adjacent, coloring the lines of each adjacent fault terminal with a fault color; if there is a normal class terminal between the lines colored with the fault color, coloring the line of the normal class terminal with the fault color; if there are two normal class terminals between the lines colored with the fault color, not coloring the lines of the normal class terminals with the fault color; marking the terminals of each colored part as fault points.

8. The power distribution network single-phase earth fault diagnosis and disposal method according to claim 1, characterized in that, When isolating the fault points, the method comprises the following steps: isolating the fault points from the branch line to the middle section in the line topology structure from the topological end, and opening the switch before the fault point when isolating the fault point at the topological end, and opening all the switches after the fault point and then opening the switch before the fault point when isolating the fault point at the middle section of the line.

9. The power distribution network single-phase earth fault analysis and disposal method according to claim 8, characterized in that, When the fault points are isolated from outside to inside from the topological end of the line topology, comprising: If the fault points in the line topology are single, after isolating the fault points, it is checked whether the line selection alarm signal is restored, yes, ending and exiting, otherwise, the steps of obtaining the line selection alarm signal and the line selection result of the station small current grounding line selection device and the subsequent steps are re-executed; If the fault points in the line topology are multiple, after isolating each fault point, it is checked whether the line selection alarm signal is restored, yes, ending and exiting, otherwise, the subsequent fault points are continuously isolated, if all the fault points are isolated, the line selection alarm signal is still not restored, then the steps of obtaining the line selection alarm signal and the line selection result of the station small current grounding line selection device and the subsequent steps are re-executed.

10. A power distribution network single-phase ground fault judgment and disposal system, characterized in that, Comprising a station small current grounding line selection device and a power distribution automation master station, wherein: The station small current grounding line selection device is used to trigger an alarm, and send the line selection alarm signal and the line selection result to the power distribution automation master station through a data gateway; The power distribution automation master station is used to execute the following steps: Obtaining the line selection alarm signal and the line selection result of the station small current grounding line selection device; According to the line selection result, calculating the zero sequence current change of all the station external terminals of the corresponding line; Checking the line topology, if the checking is passed, replacing the specified terminal in the line topology with a wire to obtain a new line topology; According to the zero sequence current change, the station external terminals are hierarchically clustered, the classes with the arithmetic average of the zero sequence current change greater than the preset threshold are divided into fault classes, and the classes with the arithmetic average of the zero sequence current change less than the preset threshold are divided into normal classes; According to the station external terminals corresponding to the fault classes and the normal classes in the new line topology, marking the fault points; Isolating the fault points, if the line selection alarm signal is not restored after isolating all the fault points, the above steps are iteratively executed until the line selection alarm signal is restored.

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