Single-phase grounding fault area positioning method, system, storage medium, and feeder terminal

Abstract

The present invention discloses a method, system, storage medium, and feeder terminal for locating a single-phase grounding fault section. The method includes: upon detecting that the zero-sequence voltage amplitude of a distribution line exceeds a preset voltage threshold, initiating zero-sequence voltage and zero-sequence current recording to obtain a first zero-sequence voltage waveform and a first zero-sequence current waveform; broadcasting a recording instruction and a recording start time to a surrounding area, so that transient recording-type fault indicators in the surrounding area, linked to the feeder terminal, upon receiving the recording instruction, transmit three-phase current recording waveforms for a first preset time period after the recording start time to the feeder terminal; and, when the duration after initiating the recording exceeds a preset time limit, determining the single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform, and all received three-phase current recording waveforms. This method can avoid environmental interference, reduce the communication burden of the distribution master station, and improve fault location accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of power grids, and in particular to a single-phase grounding fault zone positioning method, system, storage medium, and feeder terminal. Background Art

[0002] With the rapid development of distribution automation and distributed power generation, active single-phase ground fault location in distribution networks is gaining increasing attention. To achieve segmented single-phase ground fault location in power grids, centralized feeder automation solutions and waveform-based fault indicator centralized location solutions have been proposed. However, these technologies present the following challenges:

[0003] (1) The investment in centralized feeder automation solutions is large. Feeder terminals are installed together with switches as a complete set of equipment. The cost of the complete set of equipment is high, and power outages are required during the installation process.

[0004] (2) Centralized positioning scheme for transient waveform type fault indicators. Since transient waveform type fault indicators judge the rise and fall of single-phase voltage by detecting the electric field to the ground, the judgment accuracy is not high and they are easily affected by environmental interference. It is difficult to set the threshold for starting the waveform recording. If the threshold is set too low, the waveform will be recorded frequently. If the threshold is set too high, the sensitivity will deteriorate and it will be difficult to start the high-resistance grounding fault. Summary of the Invention

[0005] The present invention aims to at least partially address one of the technical problems in the related art. To this end, the first objective of the present invention is to provide a method for locating a single-phase ground fault section. This method can avoid environmental interference, reduce the communication burden on the distribution automation master station, improve the accuracy of single-phase ground fault location, and save costs.

[0006] A second object of the present invention is to provide a computer-readable storage medium.

[0007] The third object of the present invention is to provide a feeder terminal.

[0008] A fourth objective of the present invention is to provide a single-phase grounding fault section locating system.

[0009] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present invention proposes a method for locating a single-phase grounding fault section, comprising the following steps: when it is detected that the zero-sequence voltage amplitude of the distribution line exceeds a preset voltage threshold, starting the zero-sequence voltage and zero-sequence current recording to obtain a first zero-sequence voltage waveform and a first zero-sequence current waveform; broadcasting the recording instruction and the recording start time to the surrounding area, so that the transient recording type fault indicator linked to the feeder terminal in the surrounding area sends the three-phase current recording waveform of the first preset time period after the recording start time to the feeder terminal when receiving the recording instruction; when the duration after starting the recording exceeds the preset time limit, determining the single-phase grounding fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and all the received three-phase current recording waveforms, wherein the time period corresponding to the preset time limit is the first time period.

[0010] In addition, the single-phase grounding fault section location method according to the embodiment of the present invention may also have the following additional technical features:

[0011] According to one embodiment of the present invention, determining the single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform and all received three-phase current recording waveforms includes: obtaining corresponding multiple second zero-sequence current waveforms based on the three-phase current recording waveforms of each transient waveform-type fault indicator; judging whether the first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and the second zero-sequence current amplitude corresponding to the multiple second zero-sequence current waveforms both exceed a preset current threshold; if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient waveform-type fault indicator both exceed the preset current threshold, determining that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient waveform-type fault indicator are located.

[0012] According to one embodiment of the present invention, after determining that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient waveform fault indicator are located, it also includes: using a preset differential filter to perform differential filtering on the first zero-sequence voltage waveform to obtain a first zero-sequence voltage differential filtering value; using a preset bandpass filter to perform bandpass filtering on the first zero-sequence current waveform to obtain a first zero-sequence current bandpass filtering value; calculating a first correlation coefficient between the first zero-sequence current bandpass filtering value and the first zero-sequence voltage differential filtering value; if the first correlation coefficient is less than a first preset threshold, it is determined that the single-phase grounding fault occurs in the section after the feeder terminal.

[0013] According to one embodiment of the present invention, after determining that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient oscillographic fault indicator are located, it also includes: using the preset bandpass filter to bandpass filter the second zero-sequence current waveform to obtain a second zero-sequence current bandpass filter value; calculating a second correlation coefficient between the second zero-sequence current bandpass filter value and the first zero-sequence voltage differential filter value; if the second correlation coefficient is less than a second preset threshold, determining that the single-phase grounding fault occurs in the section after the kth transient oscillographic fault indicator, wherein k is a positive integer.

[0014] According to one embodiment of the present invention, the second zero-sequence current waveform is obtained by the following formula: Among them, I0(n) is the zero-sequence current value at the nth sampling moment, I A (n), I B (n), I C (n) are the three-phase current values ​​of A, B, and C at the nth sampling moment.

[0015] According to one embodiment of the present invention, the first zero-sequence voltage differential value is obtained by the following formula: Among them, h D1 is the preset differential filter, [U0 FTU ] D1 (n) is the first zero-sequence voltage differential value at the nth sampling moment, N is a positive integer, U0 FTU (n) is the first zero-sequence voltage value at the nth sampling moment.

[0016] According to one embodiment of the present invention, the first zero-sequence current bandpass filtering value is obtained by the following formula: Among them, h BP is the preset bandpass filter, [I0 FTU ] BP (n) is the first zero-sequence current bandpass filter value at the nth sampling moment, I0 FTU (n) is the first zero-sequence current value at the nth sampling moment; the second zero-sequence current bandpass filtered value is obtained by the following formula: Among them, h BP is the preset bandpass filter, [I0 FI,k ] BP (n) is the second zero-sequence current bandpass filter value at the nth sampling moment, I0 FI,k (n) is the second zero-sequence current value at the nth sampling moment.

[0017] According to one embodiment of the present invention, the first correlation coefficient is obtained by the following formula:

[0018]

[0019] The second correlation coefficient is obtained by the following formula

[0020]

[0021] Among them, [U0 FTU ] D1 (n) is the first zero-sequence voltage differential value at the nth sampling moment, [I0 FTU ] BP (n) is the first zero-sequence current bandpass filter value at the nth sampling moment, [I0 FI,k ] BP (n) is the second zero-sequence current band-pass filtered value at the n-th sampling moment, and N is a positive integer.

[0022] According to one embodiment of the present invention, the method further comprises: sending the single-phase grounding fault section to a distribution automation master station of the distribution line.

[0023] To achieve the above objectives, a second embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the single-phase grounding fault section locating method of the present invention is implemented.

[0024] To achieve the above objectives, the third embodiment of the present invention proposes a feeder terminal, including a memory, a processor and a computer program stored in the memory. When the computer program is executed by the processor, the above-mentioned single-phase grounding fault section locating method is implemented.

[0025] To achieve the above-mentioned purpose, the fourth embodiment of the present invention proposes a single-phase grounding fault section locating system, which includes: a feeder terminal, which is used to start zero-sequence voltage and zero-sequence current recording when it detects that the zero-sequence voltage amplitude of the distribution line exceeds a preset voltage threshold, obtain a first zero-sequence voltage waveform and a first zero-sequence current waveform, and broadcast the recording instruction and the recording start time to the surrounding area; a transient recording fault indicator linked to the feeder terminal, which is used to send the three-phase current recording waveform of the first preset time period after the recording start time to the feeder terminal when receiving the recording instruction; the feeder terminal is also used to determine the single-phase grounding fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and all received three-phase current recording waveforms when the duration after starting the recording exceeds the preset time limit, wherein the time period corresponding to the preset time limit is the first time period.

[0026] In addition, the single-phase grounding fault section locating system according to the embodiment of the present invention also has the following additional technical features:

[0027] According to one embodiment of the present invention, when the feeder terminal determines the single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform and all received three-phase current recording waveforms, it is specifically used to: obtain corresponding multiple second zero-sequence current waveforms based on the three-phase current recording waveforms of each transient waveform-type fault indicator; determine whether the first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and the second zero-sequence current amplitude corresponding to the multiple second zero-sequence current waveforms both exceed a preset current threshold; if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient waveform-type fault indicator both exceed the preset current threshold, it is determined that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient waveform-type fault indicator are located, where k is a positive integer.

[0028] According to one embodiment of the present invention, after determining that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient waveform fault indicator are located, the feeder terminal is further used to: use a preset differential filter to perform differential filtering on the first zero-sequence voltage waveform to obtain a first zero-sequence voltage differential filtering value; use a preset bandpass filter to perform bandpass filtering on the first zero-sequence current waveform to obtain a first zero-sequence current bandpass filtering value; calculate a first correlation coefficient between the first zero-sequence current bandpass filtering value and the first zero-sequence voltage differential filtering value; if the first correlation coefficient is less than a first preset threshold, determine that the single-phase grounding fault occurs in the section after the feeder terminal.

[0029] According to one embodiment of the present invention, after determining that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient oscillographic fault indicator are located, the feeder terminal is further used to: use the preset bandpass filter to bandpass filter the second zero-sequence current waveform to obtain a second zero-sequence current bandpass filter value; calculate a second correlation coefficient between the second zero-sequence current bandpass filter value and the first zero-sequence voltage differential filter value; if the second correlation coefficient is less than a second preset threshold, determine that the single-phase grounding fault occurs in the section after the kth transient oscillographic fault indicator.

[0030] According to one embodiment of the present invention, the system further includes a distribution automation master station, and the feeder terminal is further configured to send the single-phase grounding fault section to the distribution automation master station of the distribution line.

[0031] According to the single-phase grounding fault zone location method, system, storage medium, and feeder terminal embodiments of the present invention, more accurate single-phase grounding fault detection is achieved by detecting zero-sequence voltage exceeding a threshold, thereby avoiding environmental interference. Furthermore, the transient waveform-recording fault indicator only needs to upload the three-phase current waveform at a specified moment to the nearest feeder terminal, reducing the communication burden on the distribution automation master station. The feeder terminal and transient waveform-recording fault indicator are linked to improve the accuracy of single-phase grounding fault location. Furthermore, this solution can locate single-phase grounding fault sections without installing switches and feeder terminal equipment, thus saving costs.

[0032] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a flow chart of a method for locating a single-phase grounding fault zone according to an embodiment of the present invention;

[0034] Figure 2 is a flowchart of step S103 of an embodiment of the present invention;

[0035] Figure 3 is a flowchart of step S103 of another embodiment of the present invention;

[0036] Figure 4 It is a schematic structural diagram of a power distribution line according to a specific embodiment of the present invention;

[0037] Figure 5 is a schematic diagram of a fault location according to a specific embodiment of the present invention;

[0038] Figure 6 is a schematic diagram of a fault location of another specific embodiment of the present invention;

[0039] Figure 7 This is a schematic diagram of a fault location in another specific embodiment of the present invention.

[0040] Figure 8 It is a structural block diagram of a single-phase grounding fault zone locating system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0042] Please refer to the following Figure 1-8And specific implementation methods describe the single-phase grounding fault area locating method, system, storage medium, and feeder terminal of the embodiment of the present invention.

[0043] Figure 1 This is a flow chart of a method for locating a single-phase grounding fault zone according to an embodiment of the present invention.

[0044] In this embodiment, the execution subject of the single-phase grounding fault area locating method may be a feeder terminal. Figure 1 As shown in FIG, the specific steps of the method for locating the single-phase grounding fault area are:

[0045] S101 , when it is detected that the zero-sequence voltage amplitude of the distribution line exceeds a preset voltage threshold, zero-sequence voltage and zero-sequence current waveform recording is started to obtain a first zero-sequence voltage waveform and a first zero-sequence current waveform.

[0046] Among them, the zero-sequence voltage amplitude can be detected by the voltage transformer on the distribution line. The feeder terminal can communicate with the voltage transformer to obtain the zero-sequence voltage amplitude, and then determine whether the zero-sequence voltage amplitude exceeds the preset voltage threshold. The preset voltage threshold can be calibrated as needed.

[0047] S102, broadcasting the recording instruction and the recording start time to the surrounding area, so that the transient recording type fault indicator linked to the feeder terminal in the surrounding area sends the three-phase current recording waveform of the first preset time period after the recording start time to the feeder terminal when receiving the recording instruction.

[0048] Specifically, one or more transient waveform-recording fault indicators linked to the feeder terminal can be pre-installed on the distribution lines surrounding the feeder terminal. The feeder terminal can broadcast a waveform recording instruction and the recording start time to the surrounding area via wireless broadcasting. Upon receiving the waveform recording instruction, the corresponding transient waveform-recording fault indicator transmits the three-phase current waveform recording for the first preset time period after the recording start time to the feeder terminal. The first preset time period can be relatively short, thereby avoiding the transmission of unnecessary waveforms.

[0049] S103, when the duration after starting the recording exceeds the preset time limit, determine the single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform and all received three-phase current recording waveforms, wherein the time period corresponding to the preset time limit is the first time period.

[0050] This single-phase grounding fault section locating method can achieve more accurate single-phase grounding fault initiation based on the zero-sequence voltage amplitude exceeding a preset voltage threshold, avoid environmental interference, and improve the accuracy of transient waveform recording type fault indicator recording initiation; single-phase grounding fault locating can be performed by linking the feeder terminal and the transient waveform recording type fault indicator, which can improve positioning accuracy and does not require the installation of a large number of switches and feeder terminal complete sets of equipment, thereby reducing costs.

[0051] Figure 2 FIG. 1 is a flowchart of step S103 according to an embodiment of the present invention.

[0052] See also Figure 2 Determining a single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform, and all received three-phase current recording waveforms may include the following steps:

[0053] S201 , obtaining corresponding multiple second zero-sequence current waveforms according to the three-phase current waveforms of each transient waveform-recording type fault indicator.

[0054] Specifically, the second zero-sequence current waveform can be obtained by the following formula:

[0055]

[0056] Among them, I0(n) is the zero-sequence current value at the nth sampling moment, I A (n), I B (n), I C (n) are the three-phase current values ​​of A, B, and C at the nth sampling moment.

[0057] S202 , determining whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and a second zero-sequence current amplitude corresponding to a plurality of second zero-sequence current waveforms all exceed a preset current threshold.

[0058] S203: If the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the k-th transient oscillographic fault indicator both exceed a preset current threshold, it is determined that the single-phase grounding fault occurs in the area where the feeder terminal and the k-th transient oscillographic fault indicator are located, where k is a positive integer.

[0059] Figure 3 is a flowchart of step S103 of another embodiment of the present invention.

[0060] Specifically, see Figure 3 After determining that the single-phase grounding fault occurs in the feeder terminal and the area where the kth transient waveform fault indicator is located, a centralized analysis is performed on the area where the single-phase grounding fault is located, including the following steps:

[0061] S301 , performing differential filtering on a first zero-sequence voltage waveform using a preset differential filter to obtain a first zero-sequence voltage differential filtering value.

[0062] Specifically, the first zero-sequence voltage differential value can be obtained by the following formula:

[0063]

[0064] Among them, hD1 is the preset differential filter, [U0 FTU ] D1 (n) is the first zero-sequence voltage differential value at the nth sampling moment, N is a positive integer, U0 FTU (n) is the first zero-sequence voltage value at the nth sampling moment.

[0065] S302 , using a preset bandpass filter to perform bandpass filtering on the first zero-sequence current waveform and the second zero-sequence current waveform respectively, to obtain a first zero-sequence current bandpass filtered value and a second zero-sequence current bandpass filtered value.

[0066] Specifically, the first zero-sequence current bandpass filtering value can be obtained by the following formula:

[0067]

[0068] Among them, h BP is the preset bandpass filter, [I0 FTU ] BP (n) is the first zero-sequence current bandpass filter value at the nth sampling moment, I0 FTU (n) is the first zero-sequence current value at the nth sampling moment.

[0069] The second zero-sequence current bandpass filter value can be obtained by the following formula:

[0070]

[0071] Among them, [I0 FI,k ] BP (n) is the second zero-sequence current bandpass filter value at the nth sampling moment, I0 FI,k (n) is the second zero-sequence current value at the nth sampling moment.

[0072] S303 , respectively calculating a first correlation coefficient between the first zero-sequence current band-pass filtered value and the first zero-sequence voltage differential filtered value and a second correlation coefficient between the second zero-sequence current band-pass filtered value and the first zero-sequence voltage differential filtered value.

[0073] Specifically, the first correlation coefficient can be obtained by the following formula:

[0074]

[0075] The second correlation coefficient can be obtained by the following formula

[0076]

[0077] S304: If the first correlation coefficient is less than the first preset threshold, it is determined that the single-phase grounding fault occurs in the section after the feeder terminal; if the second correlation coefficient is less than the second preset threshold, it is determined that the single-phase grounding fault occurs in the section after the kth transient waveform fault indicator.

[0078] The first preset threshold may be equal to the second preset threshold, for example, both are 0.

[0079] In some embodiments of the present invention, after determining the single-phase ground fault section, the section can be sent to the distribution automation master station. This eliminates the need to upload only the section location results to the distribution automation master station, eliminating the need to upload large amounts of waveforms and avoiding unnecessary data transmission.

[0080] For ease of understanding, the following Figure 4-7 The single-phase grounding fault section location method of the present invention is described by a specific embodiment:

[0081] See also Figure 4 The line structure of the distribution line includes a feeder terminal 400 and six transient waveform fault indicators 401-406.

[0082] The current flows in from the location of transient oscillographic fault indicator 401 and splits into two branches at the location of feeder terminal 400. One branch flows through the locations of transient oscillographic fault indicators 402 and 403 and flows out from the location of transient oscillographic fault indicator 403. The other branch flows through the location of transient oscillographic fault indicator 404 and splits into two branches again at this location. One branch flows through the location of transient oscillographic fault indicator 405 and flows out from this location. The other branch flows through the location of transient oscillographic fault indicator 406 and flows out from this location. The specific steps for determining the fault section are as follows:

[0083] (1) When the feeder terminal 400 detects that the zero-sequence voltage exceeds the threshold, it records its own zero-sequence voltage and zero-sequence current, and sends a recording start command and recording start time to the transient recording type fault indicators 401-406 through wireless broadcasting;

[0084] (2) After receiving the recording instruction, the transient waveform-recording fault indicators 401-406 send the three-phase current waveforms of the specified time period (i.e., the first preset time period after the recording start time) to the feeder terminal 400;

[0085] (3) The feeder terminal 400 starts timing after starting the waveform recording. When the time exceeds the limit (i.e., the time corresponding to the first preset time period), the feeder terminal 400 determines the waveform that needs to be centrally analyzed from its own waveform recording and the waveforms of the transient waveform fault indicators 401-406 collected.

[0086] It should be noted that if the recording time of the feeder terminal exceeds the limit, there is redundancy in its own recording waveform and / or the received transient recording type fault indicator recording waveform, then the feeder terminal can filter out the waveform of a certain time period after the recording is started from its own recording waveform and the received recording waveform, and conduct centralized analysis. The certain time period may be less than or equal to the first preset time period.

[0087] (4) The specific process of centralized analysis is as follows:

[0088] (a) The feeder terminal 400 calculates the zero-sequence current of the transient oscillographic fault indicators 401-406 and determines whether the zero-sequence current of the transient oscillographic fault indicators 401-406 and the zero-sequence current of the feeder terminal 400 exceed a preset current threshold. If the zero-sequence current exceeds the preset current threshold, it indicates that a single-phase grounding fault may have occurred in the area where the feeder terminal 400 and its linked transient oscillographic fault indicators 401-406 are located;

[0089] (b) Calculate the zero-sequence voltage differential at the feeder terminal 400;

[0090] (c) calculating the bandpass filtered value of the zero-sequence current at the feeder terminal 400 and the transient waveform fault indicators 401-406;

[0091] (d) calculating the correlation coefficient between the differential of the zero-sequence voltage at the feeder terminal 400 and the bandpass filtered results of the zero-sequence current at the feeder terminal 400 and the transient waveform-type fault indicators 401-406;

[0092] (e) If the correlation coefficient is less than a preset threshold value, such as 0, it indicates that the fault point is downstream of the device. If the correlation coefficient is greater than the preset threshold value, such as 0, it indicates that the fault point is upstream of the device.

[0093] As a feasible implementation, if the correlation coefficients between the bandpass filtering results of the zero-sequence currents of the feeder terminal 400 and the transient waveform-type fault indicators 401-406 and the zero-sequence voltage differentials of the feeder terminal 400 are all greater than a preset threshold, it indicates that a single-phase grounding fault is located in the upstream line of the transient waveform-type fault indicator 401, such as Figure 5 shown.

[0094] As a feasible implementation method, if the correlation coefficient between the bandpass filtering results of the zero-sequence currents of the feeder terminal 400 and the transient waveform-type fault indicators 401, 402, and 403 and the zero-sequence voltage differential of the feeder terminal 400 is less than the threshold, it indicates that the single-phase grounding fault is on the line behind the transient waveform-type fault indicator 403, such as Figure 6 shown.

[0095] As a feasible implementation method, if the correlation coefficients between the bandpass filtering results of the zero-sequence current of the feeder terminal 400 and the transient waveform-type fault indicator 401 and the zero-sequence voltage differential of the feeder terminal 400 are all less than the threshold, it means that the single-phase grounding fault is after the feeder terminal 400 and there are two possible fault sections. One fault section is the line between the feeder terminal 400 and the transient waveform-type fault indicator 402, and the other fault section is the line between the feeder terminal 400 and the transient waveform-type fault indicator 404. Figure 7 shown.

[0096] In summary, in the single-phase grounding fault zone location method of the embodiment of the present invention, the feeder terminal starts recording its own zero-sequence voltage and zero-sequence current based on the zero-sequence voltage exceeding the limit, and simultaneously issues a recording instruction to the linked transient recording type fault indicator. The transient recording type fault indicator sends the A, B, and C three-phase current recording waveforms at the specified time to the linked feeder terminal. The feeder terminal conducts a centralized analysis of the recording waveforms to determine whether the single-phase grounding fault is within the area where the feeder terminal and its linked transient recording type fault indicator are located. If so, the fault section is reported to the distribution automation master station. This technical solution not only takes advantage of the feeder terminal's ability to accurately start the single-phase grounding fault recording based on the zero-sequence voltage, but also takes advantage of the low cost and easy installation of the transient recording type fault indicator. It can fully utilize the respective advantages of the feeder terminal and the transient recording type fault indicator, further narrow the single-phase grounding fault location section, and achieve more accurate single-phase grounding fault section location.

[0097] Furthermore, the present invention provides a computer-readable storage medium.

[0098] In an embodiment of the present invention, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned single-phase grounding fault section locating method is implemented.

[0099] The present invention also proposes a feeder terminal, comprising a memory, a processor and a computer program stored on the above-mentioned computer-readable storage medium. When the computer program is executed by the processor, the above-mentioned single-phase grounding fault section locating method is implemented.

[0100] Figure 8 It is a structural block diagram of a single-phase grounding fault section locating system according to an embodiment of the present invention.

[0101] like Figure 8 As shown, the single-phase grounding fault section location system 800 includes: a feeder terminal 810 and a transient waveform recording type fault indicator 820 linked to the feeder terminal. The number of the transient waveform recording type fault indicator 820 can be one or more.

[0102] The feeder terminal 810 is used to start zero-sequence voltage and zero-sequence current recording when it detects that the zero-sequence voltage amplitude of the distribution line exceeds a preset voltage threshold, obtain a first zero-sequence voltage waveform and a first zero-sequence current waveform, and broadcast the recording instruction and the recording start time to the surrounding area. The transient recording fault indicator 820 linked to the feeder terminal is used to send the three-phase current recording waveform for the first preset time period after the recording start time to the feeder terminal when the recording instruction is received. The feeder terminal 810 is also used to determine the single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform, and all received three-phase current recording waveforms when the duration after the recording is started exceeds a preset time limit, wherein the time period corresponding to the preset time limit is the first time period.

[0103] Specifically, when the feeder terminal 810 determines the single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform and all received three-phase current recording waveforms, it can be specifically used to: obtain corresponding multiple second zero-sequence current waveforms based on the three-phase current recording waveforms of each transient recording type fault indicator 820; determine whether the first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and the second zero-sequence current amplitudes corresponding to the multiple second zero-sequence current waveforms all exceed the preset current threshold; if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient recording type fault indicator both exceed the preset current threshold, it is determined that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient recording type fault indicator 820 are located, where k is a positive integer.

[0104] In this embodiment, the second zero-sequence current waveform can be obtained by the following formula:

[0105]

[0106] Among them, I0(n) is the zero-sequence current value at the nth sampling moment, I A (n), I B (n), I C (n) are the three-phase current values ​​of A, B, and C at the nth sampling moment.

[0107] Furthermore, after determining that the single-phase grounding fault occurs in the area where the feeder terminal 810 and the kth transient waveform fault indicator 820 are located, the feeder terminal 810 is further configured to: use a preset differential filter to perform differential filtering on the first zero-sequence voltage waveform to obtain a first zero-sequence voltage differential filtering value; use a preset bandpass filter to perform bandpass filtering on the first zero-sequence current waveform and the second zero-sequence current waveform to obtain a first zero-sequence current bandpass filtering value and a second zero-sequence current bandpass filtering value; respectively calculate a first correlation coefficient between the first zero-sequence current bandpass filtering value and the first zero-sequence voltage differential filtering value and a second correlation coefficient between the second zero-sequence current bandpass filtering value and the first zero-sequence voltage differential filtering value; if the first correlation coefficient is less than a first preset threshold, determine that the single-phase grounding fault occurs in a section after the feeder terminal 810; if the second correlation coefficient is less than a second preset threshold, determine that the single-phase grounding fault occurs in a section after the kth transient waveform fault indicator 820.

[0108] Among them, the first zero-sequence voltage differential value can be obtained by the following formula:

[0109]

[0110] Among them, h D1 is the preset differential filter, [U0 FTU ] D1 (n) is the first zero-sequence voltage differential value at the nth sampling moment, N is a positive integer, U0 FTU (n) is the first zero-sequence voltage value at the nth sampling moment.

[0111] The first zero-sequence current bandpass filter value can be obtained by the following formula:

[0112]

[0113] Among them, h BP is the preset bandpass filter, [I0 FTU ] BP (n) is the first zero-sequence current bandpass filter value at the nth sampling moment, I0 FTU (n) is the first zero-sequence current value at the nth sampling moment.

[0114] The second zero-sequence current bandpass filter value can be obtained by the following formula:

[0115]

[0116] Among them, [I0 FI,k ] BP (n) is the second zero-sequence current bandpass filter value at the nth sampling moment, I0 FI,k (n) is the second zero-sequence current value at the nth sampling moment.

[0117] The first correlation coefficient can be obtained by the following formula

[0118]

[0119] The second correlation coefficient can be obtained by the following formula

[0120]

[0121] The feeder terminal 810 may also be used to send the single-phase grounding fault section to the distribution automation master station.

[0122] It should be noted that, for other specific implementations of the single-phase grounding fault section locating system according to the embodiment of the present invention, reference may be made to the specific implementations of the single-phase grounding fault section locating method according to the above embodiment of the present invention.

[0123] In summary, the single-phase grounding fault section locating system of the embodiment of the present invention not only takes advantage of the characteristic that the feeder terminal can realize accurate startup of the single-phase grounding fault recording according to the zero-sequence voltage, but also takes advantage of the low cost and easy installation of the transient recording type fault indicator. It can give full play to the respective advantages of the feeder terminal and the transient recording type fault indicator, further narrow the single-phase grounding fault locating section, and realize more accurate single-phase grounding fault section locating.

[0124] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device), or in conjunction with such instruction execution system, apparatus, or device. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transmit a program for use by an instruction execution system, apparatus, or device, or in conjunction with such instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion having one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing it in a suitable manner if necessary, and then storing it in a computer memory.

[0125] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0126] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0127] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0128] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0129] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0130] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0131] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for locating a single-phase grounding fault section, characterized in that: The method is applied to a feeder terminal and comprises the following steps: When it is detected that the zero-sequence voltage amplitude of the distribution line exceeds a preset voltage threshold, zero-sequence voltage and zero-sequence current waveform recording is started to obtain a first zero-sequence voltage waveform and a first zero-sequence current waveform; Broadcasting a recording instruction and a recording start time to a surrounding area, so that a transient recording type fault indicator linked to the feeder terminal in the surrounding area, upon receiving the recording instruction, sends a three-phase current recording waveform for a first preset time period after the recording start time to the feeder terminal; When the duration after starting the waveform recording exceeds a preset time limit, determining the single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform, and all received three-phase current waveform recordings, wherein the time period corresponding to the preset time limit is the first preset time period; The determining of the single-phase grounding fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform, and all received three-phase current recording waveforms includes: Obtaining corresponding multiple second zero-sequence current waveforms according to the three-phase current waveforms of each transient waveform-recording type fault indicator; determining whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and a second zero-sequence current amplitude corresponding to the plurality of second zero-sequence current waveforms all exceed a preset current threshold; If both the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient waveform fault indicator exceed the preset current threshold, it is determined that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient waveform fault indicator are located, and then the first zero-sequence voltage waveform is differentially filtered using a preset differential filter to obtain a first zero-sequence voltage differential filtering value; the first zero-sequence current waveform is band-pass filtered using a preset band-pass filter to obtain a first zero-sequence current band-pass filtering value; the first correlation coefficient between the first zero-sequence current band-pass filtering value and the first zero-sequence voltage differential filtering value is calculated; if the first correlation coefficient is less than the first preset threshold, it is determined that the single-phase grounding fault occurs in the section after the feeder terminal; if the first correlation coefficient is greater than the first preset threshold, it is determined that the single-phase grounding fault occurs in the section before the feeder terminal, where k is a positive integer.

2. The method for locating a single-phase grounding fault section according to claim 1, wherein: After determining that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient waveform recording type fault indicator are located, the method further includes: Using the preset bandpass filter to perform bandpass filtering on the second zero-sequence current waveform to obtain a second zero-sequence current bandpass filtered value; Calculating a second correlation coefficient between the second zero-sequence current bandpass filtered value and the first zero-sequence voltage differential filtered value; If the second correlation coefficient is less than a second preset threshold, it is determined that the single-phase grounding fault occurs in the section after the kth transient waveform recording type fault indicator.

3. The method for locating a single-phase grounding fault section according to claim 1, wherein: The second zero-sequence current waveform is obtained by the following formula: Among them, I0(n) is the zero-sequence current value at the nth sampling moment, I A (n), I B (n), I C (n) are the three-phase current values ​​of A, B, and C at the nth sampling moment.

4. The method for locating a single-phase grounding fault section according to claim 2, wherein: The first zero-sequence voltage differential filtering value is obtained by the following formula: Among them, h D1 is the preset differential filter, [U0 FTU ] D1 (n) is the first zero-sequence voltage differential filter value at the nth sampling moment, N is a positive integer, U0 FTU (n) is the first zero-sequence voltage value at the nth sampling moment.

5. The method for locating a single-phase grounding fault section according to claim 2, wherein: The first zero-sequence current bandpass filter value is obtained by the following formula: Among them, h BP is the preset bandpass filter, [I0 FTU ] BP (n) is the first zero-sequence current bandpass filter value at the nth sampling moment, I0 FTU (n) is the first zero-sequence current value at the nth sampling moment; The second zero-sequence current bandpass filter value is obtained by the following formula: Among them, h BP is the preset bandpass filter, [I0 FI,k ] BP (n) is the second zero-sequence current bandpass filter value at the nth sampling moment, I0 FI,k (n) is the second zero-sequence current value at the nth sampling moment.

6. The method for locating a single-phase grounding fault section according to claim 2, wherein: The first correlation coefficient is obtained by the following formula The second correlation coefficient is obtained by the following formula Among them, [U0 FTU ] D1 (n) is the first zero-sequence voltage differential filter value at the nth sampling moment, [I0 FTU ] BP (n) is the first zero-sequence current bandpass filter value at the nth sampling moment, [I0 FI,k ] BP (n) is the second zero-sequence current band-pass filtered value at the n-th sampling moment, and N is a positive integer.

7. The method for locating a single-phase grounding fault section according to any one of claims 1 to 6, characterized in that: The method further comprises: The single-phase grounding fault section is sent to the distribution automation master station of the distribution line.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the single-phase grounding fault section locating method according to any one of claims 1 to 7 is implemented.

9. A feeder terminal comprising a memory, a processor, and a computer program stored in the memory, characterized in that: When the computer program is executed by the processor, the single-phase grounding fault section locating method according to any one of claims 1 to 7 is implemented.

10. A single-phase grounding fault section location system, characterized in that: The system comprises: The feeder terminal is configured to start recording the zero-sequence voltage and zero-sequence current waveforms when detecting that the zero-sequence voltage amplitude of the distribution line exceeds a preset voltage threshold, obtain a first zero-sequence voltage waveform and a first zero-sequence current waveform, and broadcast a recording instruction and a recording start time to a surrounding area; A transient waveform recording type fault indicator linked to the feeder terminal is used to send the three-phase current waveform recording for a first preset time period after the recording start time to the feeder terminal upon receiving the waveform recording instruction; The feeder terminal is further configured to determine a single-phase grounding fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform, and all received three-phase current recording waveforms when the duration after the recording is started exceeds a preset time limit, wherein the time period corresponding to the preset time limit is the first preset time period; When the feeder terminal determines the single-phase grounding fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform, and all received three-phase current recording waveforms, the feeder terminal is specifically configured to: Obtaining corresponding multiple second zero-sequence current waveforms according to the three-phase current waveforms of each transient waveform-recording type fault indicator; determining whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and a second zero-sequence current amplitude corresponding to the plurality of second zero-sequence current waveforms all exceed a preset current threshold; If both the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient waveform fault indicator exceed the preset current threshold, it is determined that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient waveform fault indicator are located, and then the first zero-sequence voltage waveform is differentially filtered using a preset differential filter to obtain a first zero-sequence voltage differential filtering value; the first zero-sequence current waveform is band-pass filtered using a preset band-pass filter to obtain a first zero-sequence current band-pass filtering value; the first correlation coefficient between the first zero-sequence current band-pass filtering value and the first zero-sequence voltage differential filtering value is calculated; if the first correlation coefficient is less than the first preset threshold, it is determined that the single-phase grounding fault occurs in the section after the feeder terminal; if the first correlation coefficient is greater than the first preset threshold, it is determined that the single-phase grounding fault occurs in the section before the feeder terminal, where k is a positive integer.

11. The single-phase grounding fault section locating system according to claim 10, characterized in that: After determining that the single-phase grounding fault occurs in the area where the feeder terminal and the kth transient waveform recording fault indicator are located, the feeder terminal is further configured to: Using the preset bandpass filter to perform bandpass filtering on the second zero-sequence current waveform to obtain a second zero-sequence current bandpass filtered value; Calculating a second correlation coefficient between the second zero-sequence current bandpass filtered value and the first zero-sequence voltage differential filtered value; If the second correlation coefficient is less than a second preset threshold, it is determined that the single-phase grounding fault occurs in the section after the kth transient waveform recording fault indicator.

12. The single-phase grounding fault section locating system according to any one of claims 10-11, characterized in that: The system also includes a distribution automation master station, The feeder terminal is also used to send the single-phase grounding fault section to the distribution automation master station of the distribution line.

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