Improved traveling wave distance measurement method for power distribution network fault location analysis

Abstract

The application discloses an improved traveling wave distance measurement method for fault location analysis of a power distribution network, and relates to the technical field of power distribution networks. The method solves the problem of positioning deviation caused by a traditional single wave speed model, and especially the problem of false fault points caused by refraction and reflection at the connection between a cable and an overhead line. The method performs waveform translation and coincidence verification, calculates the amplitude difference average under different translation amounts, automatically identifies the optimal time alignment point, and locks the associated time difference t1. This process can effectively correct the time error caused by signal distortion, non-synchronous sampling and the like, and can improve the time difference accuracy from the microsecond level to the nanosecond level, thereby laying a foundation for subsequent accurate positioning. In the locked range interval, a plurality of associated points are randomly selected, a corrected waveform is constructed based on the attenuation ratio, and repeated verification is performed. The optimal solution is selected through a characteristic mean minimization algorithm. The mechanism can effectively suppress single measurement point error, and can improve the robustness of the positioning result through statistical average effect.

Description

Technical Field

[0001] This invention relates to the field of power distribution network technology, specifically to an improved method for traveling wave ranging in power distribution network fault location analysis. Background Technology

[0002] As the "last mile" connecting the power system and users, the safe and stable operation of the distribution network directly affects power supply reliability and user experience. However, distribution networks are characterized by complex topologies (such as radial, ring, and multi-branch structures), diverse line types (a mix of overhead and cable lines), and frequent fault types (especially single-phase grounding and high-resistance faults), making fault location difficult. Traditional fault location methods, such as impedance methods and signal injection methods, are affected by factors such as changes in line parameters and uncertainties in grounding resistance, resulting in low location accuracy (often with errors reaching hundreds of meters), making it difficult to meet the needs of rapid power restoration in smart distribution networks.

[0003] Traveling wave ranging technology has become a research hotspot for fault location in distribution networks due to its advantages of high positioning accuracy and fast response speed. Its core principle is to calculate the location of the fault point by utilizing the propagation characteristics (such as propagation time and waveform characteristics) of the transient traveling wave generated by the fault in the line.

[0004] The wave velocity difference between overhead lines and cables is significant. The traditional single wave velocity model leads to positioning errors, especially at the cable-overhead line connection, where refraction and reflection can easily create false fault points.

[0005] Traditional two-end ranging relies on high-precision clock synchronization (nanosecond level), but distributed monitoring nodes in the distribution network often experience synchronization deviations due to hardware cost limitations or communication delays, leading to time difference calculation errors. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an improved traveling wave ranging method for fault location analysis in power distribution networks. This method solves the problem of location deviation caused by traditional single wave velocity models, especially the problem of false fault points easily generated by refraction and reflection at cable-overhead line connections.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an improved traveling wave ranging method for fault location analysis in distribution networks, comprising the following steps:

[0008] Step 1: Confirm the time of the transient traveling wave signals received by the monitoring nodes on both sides of the power distribution network transmission line, and based on the confirmed time difference, confirm and mark the line range where the fault point is located. The specific method is as follows:

[0009] Based on the generated transient traveling wave signal, the reception times T1 and T2 associated with the monitoring nodes on both sides of the corresponding transmission line receiving such transient traveling wave signal are confirmed, where T1 and T2 represent different reception times associated with different monitoring nodes.

[0010] The time difference Ct between the two sets of receiving times is determined by Ct = |T1-T2|. Based on the set transmission speed v, the value difference between the two transmission line segments is determined, and the value difference = Ct × v, where v is a preset value.

[0011] From the receiving times T1 and T2, select the minimum value and record the monitoring node associated with the minimum value as the low node. Then, record another set of monitoring nodes as the high node. Randomly select a set of line nodes from the transmission line and record the line length L1 from the line node to the low node and the line length L2 from the line node to the high node. By adjusting the position of the line nodes, ensure that (L2-L1) = value difference.

[0012] Based on the identified line nodes, use these line nodes as the center point to confirm left and right, and lock in the line range where a set of fault points are located.

[0013] Step 2: Based on the signal waveforms associated with the transient traveling wave signals received by the monitoring nodes on both sides, perform synchronous verification on the two sets of signal waveforms. From the synchronous verification process, lock the optimal verification process, and from the optimal verification process, lock the associated time difference. The specific method is as follows:

[0014] The transient traveling wave signals associated with the monitoring nodes on both sides are confirmed, and the two confirmed signal waveforms are checked for overlap. The two signal waveforms are placed in the same two-dimensional plane, with the horizontal axis representing the time line and the vertical axis representing the amplitude. The two signal waveforms are controlled to be translated left and right. During the translation control process, the amplitude difference generated when the two signal waveforms are at the same moment is recorded, and the amplitude difference is ≥0. The amplitude difference of several confirmed amplitude differences is averaged to confirm the characteristic mean associated with the corresponding translation process.

[0015] The mean values ​​of different features associated with different translation processes are confirmed, and the minimum value is selected from the confirmed mean values ​​of different features. The translation process associated with the minimum value is recorded as the optimal verification process.

[0016] Confirm the time difference between the starting points of the two sets of signal waveforms in the optimal verification process, where the time difference is ≥ 0, and use the determined time difference as the determined associated time difference;

[0017] Step 3: Based on the determined associated time difference and line range, re-verify the time difference associated with the monitoring nodes on both sides. Based on the specific verification process, confirm the accurate location of the fault point. The specific method is as follows:

[0018] Based on the confirmed reception times T1 and T2 and the associated time difference, the reception times associated with the monitoring nodes on both sides are readjusted to Z1 and Z2.

[0019] Based on the adjusted Z1 and Z2, the line nodes are re-marked within the transmission line using the method of re-determining the line nodes in step one, and recorded as sub-nodes. It is then identified whether the sub-nodes are located within the line range. If so, the location of the sub-node is recorded as the accurate location of the fault point and displayed. If not, subsequent steps are performed to reconfirm the accurate location of the fault point.

[0020] Step 4: Randomly select associated points within the line range, and confirm the attenuation ratio based on the selected associated points and the specific line lengths on both sides. Then, based on the confirmed attenuation ratio, correct the signal waveforms associated with the monitoring nodes on both sides, and then re-verify the two sets of corrected signal waveforms to pinpoint the exact location of the fault. The specific method is as follows:

[0021] Based on the confirmed line range, a related point is randomly selected within this range, and based on the location of the related point, the distance of this related point from the line associated with the monitoring nodes on both sides is confirmed and recorded as C1 and C2 respectively.

[0022] use: Confirm the attenuation energy E1 associated with line length C1, where Eo is the preset original energy, e is the base of the natural logarithm, and a is the preset attenuation coefficient. Use B1 = (E1 ÷ Eo) to confirm the attenuation ratio B1 associated with the corresponding line.

[0023] Then, the same processing method is used to confirm the attenuation ratio B2 associated with line thread C2;

[0024] Based on the confirmed attenuation ratios B1 and B2, the monitoring nodes associated with the corresponding lines are identified. The signal waveform associated with the monitoring nodes is adjusted in reverse to increase the amplitude associated with the signal waveform, resulting in an increased corrected waveform. This corrected waveform, under the attenuation state of B1 or B2, becomes the signal waveform associated with the corresponding monitoring node.

[0025] The two sets of corrected waveforms are shifted left and right in the same two-dimensional plane. The amplitude difference between the two sets of corrected waveforms at the same moment is recorded, and the amplitude difference is ≥0. The amplitude difference of the confirmed sets of amplitude differences is averaged to confirm the characteristic mean associated with the corresponding shift process. The different characteristic means associated with different shift processes are confirmed, and the minimum value is selected from the confirmed different characteristic means to determine the optimal verification process. The associated time difference between the two sets of corrected waveforms is locked. Based on the same processing method as in step three, it is confirmed whether the currently confirmed fault point is located within the line range. If so, the confirmed fault point is marked as a point to be selected. If not, no marking is performed.

[0026] Based on the determination process of different correlation points, the determination process of several different candidate points can be completed, and the minimum value associated with different candidate points can be labeled as ZX. k Where k represents different points to be selected, and ZX is selected. k The point to be selected associated with min is recorded as the accurate location point, and based on the confirmed accurate location point, it is marked in the corresponding transmission line.

[0027] Preferably, the distance value confirmed when the line node is confirmed to be left or right is 2m.

[0028] This invention provides an improved traveling wave ranging method for fault location analysis in power distribution networks. Compared with existing technologies, it has the following advantages:

[0029] This invention uses waveform translation and overlap verification to calculate the average amplitude difference under different translation amounts, automatically identifies the optimal time alignment point, and locks the associated time difference t1. This process can effectively correct time errors caused by signal distortion, asynchronous sampling, etc., improving the time difference accuracy from the microsecond level to the nanosecond level, laying the foundation for subsequent precise positioning.

[0030] Multiple associated points are randomly selected within the locked range. A corrected waveform is constructed based on the attenuation ratio and repeatedly verified. The optimal solution is selected by minimizing the feature mean. This mechanism can effectively suppress the error of a single measurement point and improve the robustness of the positioning results through statistical averaging. Even in extreme cases such as high-resistance faults and weak traveling wave signals, the accurate location can still be locked by cross-verification of data from multiple measurement points. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figure 1 This application provides an improved traveling wave ranging method for fault location analysis in distribution networks, comprising the following steps:

[0034] Step 1: Confirm the time of the transient traveling wave signal received by the monitoring nodes on both sides of the power distribution network transmission line. Based on the confirmed time difference, determine and mark the range of the line where the fault point is located. Specifically, there are monitoring nodes on both the left and right sides of the corresponding transmission line. When there is a fault node in the corresponding transmission line, there will be a corresponding transient traveling wave signal. The corresponding signal will be transmitted to the monitoring nodes on both sides. Then, the monitoring nodes on both sides will have the specific time of signal reception, so the specific time difference can be confirmed. Based on the specific length of the corresponding transmission line, the range of the fault point can be locked, which facilitates the rapid search of the fault point in the future.

[0035] The specific method for defining the range of the fault point is as follows:

[0036] Based on the generated transient traveling wave signal, the reception times T1 and T2 associated with the monitoring nodes on both sides of the corresponding transmission line receiving such transient traveling wave signal are confirmed, where T1 and T2 represent different reception times associated with different monitoring nodes.

[0037] The time difference Ct between the two sets of receiving times is determined by Ct = |T1-T2|. Based on the set transmission speed v, the value difference between the two transmission line segments is determined, and the value difference = Ct × v, where v is a preset value, determined by the operator based on experience, and is generally consistent with the speed of light.

[0038] From the receiving times T1 and T2, select the minimum value and record the monitoring node associated with the minimum value as the low node. Then, record another set of monitoring nodes as the high node. Randomly select a set of line nodes from the transmission line and record the line length L1 from the line node to the low node and the line length L2 from the line node to the high node. By adjusting the position of the line nodes, ensure that (L2-L1) = value difference.

[0039] Based on the identified line nodes, the left and right sides are confirmed using these line nodes as the center point to lock down the line range where a set of fault points are located. In the process of left and right confirmation, the translation distance is generally taken as 2m. Based on this center point, the part of the line associated with the front and back 2m is recorded as the confirmed range. Specifically, when there is a fault point, the transient traveling wave signal generated at the corresponding point will be transmitted to the left and right monitoring nodes respectively. Based on the signal reception time at the corresponding monitoring node, the corresponding time difference can be confirmed. Then, the line segment characteristics are confirmed based on the time difference, thereby locking down the corresponding fault node position, and then the specific position of the range is confirmed.

[0040] Step 2: Based on the signal waveforms associated with the transient traveling wave signals received by the monitoring nodes on both sides, the two sets of signal waveforms are synchronously verified. From the synchronous verification process, the optimal verification process is locked, and the associated time difference is locked from the optimal verification process. Specifically, the associated time difference is the difference in the starting point of the waveform associated with the corresponding time node. That is to say, in the actual process, the signal may fluctuate earlier due to line fluctuations, thus causing a large problem with the time difference associated with the corresponding monitoring node. This part of the process is used to quickly lock the associated time difference. The specific method for quickly locking the associated time difference is as follows:

[0041] The transient traveling wave signals associated with the monitoring nodes on both sides are confirmed, and the two confirmed signal waveforms are checked for overlap. The two signal waveforms are placed in the same two-dimensional plane, with the horizontal axis representing the time line and the vertical axis representing the amplitude. The two signal waveforms are controlled to be translated left and right. During the translation control process, the amplitude difference generated when the two signal waveforms are at the same moment is recorded, and the amplitude difference is ≥0. The amplitude difference of several confirmed amplitude differences is averaged to confirm the characteristic mean associated with the corresponding translation process.

[0042] The mean values ​​of different features associated with different translation processes are confirmed, and the minimum value is selected from the confirmed mean values ​​of different features. The translation process associated with the minimum value is recorded as the optimal verification process.

[0043] Confirm the time difference between the starting points of the two sets of signal waveforms in the optimal verification process, where the time difference is ≥ 0, and use the determined time difference as the determined associated time difference;

[0044] Specifically, during the waveform verification process, the two sets of signal waveforms are shifted left and right. This allows for the identification of any time differences during the processing. Based on this identification process, the corresponding time characteristics can be effectively confirmed, and a comprehensive verification can be performed to achieve the optimal time accuracy.

[0045] Step 3: Based on the determined associated time difference and line range, re-verify the associated time difference between the monitoring nodes on both sides. Based on the specific verification process, confirm the accurate location of the fault point. Specifically, if the accurate location can be confirmed, calibration can be performed directly. If the accurate location cannot be confirmed, perform subsequent related processing steps, conduct further analysis, and reconfirm the accurate location of the fault point.

[0046] The specific method for re-verifying the monitoring nodes on both sides is as follows:

[0047] Based on the confirmed reception times T1 and T2 and the associated time difference, the reception times associated with the monitoring nodes on both sides are readjusted to Z1 and Z2. The reception time associated with the signal waveform with the starting point is kept unchanged, while the reception time associated with the signal waveform with the starting point is delayed by t1. Specifically, based on the specific translation process, the corresponding associated time difference is confirmed and the time difference is set to t1. Since the signal waveform associated with reception time T1 is earlier, the signal waveform associated with reception time T2 is later. Therefore, T1 is set to remain unchanged, i.e., T1 = Z1. Then T2 is adjusted, and the adjusted time is: Z2 = (T2 - t1). The two sets of reception times T1 and T2 are confirmed based on the confirmed associated time difference.

[0048] Based on the adjusted Z1 and Z2, the line nodes are re-marked within the transmission line using the method of re-determining the line nodes in step one, and recorded as sub-nodes. It is then identified whether the sub-nodes are located within the line range. If so, the location of the sub-node is recorded as the accurate location of the fault point and displayed. If not, subsequent steps are performed to reconfirm the accurate location of the fault point.

[0049] Specifically, after taking the corresponding time difference into account, the associated line nodes are recalibrated again. Based on the specific calibration process, under the time difference correction state, it is identified whether the confirmed corresponding line node is located within the corresponding line range. Based on the specific identification process, the accurate location of the corresponding fault point can be quickly confirmed, thereby achieving a better process calibration effect.

[0050] Step 4: Based on the confirmed line range, randomly select associated points within the line range. Then, based on the selected associated points and the specific line lengths on both sides, confirm the attenuation ratio. Next, based on the confirmed attenuation ratio, correct the signal waveforms associated with the monitoring nodes on both sides. Finally, re-verify the two sets of corrected signal waveforms to pinpoint the exact location of the fault. The specific method for pinpointing the fault is as follows:

[0051] Based on the confirmed line range, a related point is randomly selected within this range, and based on the location of the related point, the distance of this related point from the line associated with the monitoring nodes on both sides is confirmed and recorded as C1 and C2 respectively.

[0052] use: Confirm the attenuation energy E1 associated with line length C1, where Eo is the preset original energy, e is the base of the natural logarithm, generally taken as 2.718281828459045..., and a is the preset attenuation coefficient, which is determined in advance by the operator based on experience. Use B1=(E1÷Eo) to confirm the attenuation ratio B1 associated with the corresponding line.

[0053] Then, the same processing method is used to confirm the attenuation ratio B2 associated with line thread C2;

[0054] Based on the confirmed attenuation ratios B1 and B2, the monitoring nodes associated with the corresponding lines are identified. The signal waveform associated with the monitoring nodes is adjusted in reverse to increase the amplitude associated with the signal waveform, resulting in an increased corrected waveform. This corrected waveform, under the attenuation state of B1 or B2, becomes the signal waveform associated with the corresponding monitoring node.

[0055] The two sets of corrected waveforms are shifted left and right in the same two-dimensional plane. The amplitude difference between the two sets of corrected waveforms at the same moment is recorded, and the amplitude difference is ≥0. The amplitude difference of the confirmed sets of amplitude differences is averaged to confirm the characteristic mean associated with the corresponding shift process. The different characteristic means associated with different shift processes are confirmed, and the minimum value is selected from the confirmed different characteristic means to determine the optimal verification process. The associated time difference between the two sets of corrected waveforms is locked. Based on the same processing method as in step three, it is confirmed whether the currently confirmed fault point is located within the line range. If so, the confirmed fault point is marked as a point to be selected. If not, no marking is performed.

[0056] Based on the determination process of different correlation points, the determination process of several different candidate points can be completed, and the minimum value associated with different candidate points can be denoted as ZX. k Where k represents different points to be selected, and ZX is selected. k The selected point associated with min is recorded as the accurate location point. Based on the confirmed accurate location point, it is marked in the corresponding transmission line to pinpoint the accurate location of the fault point.

[0057] Specifically, by determining the process step by step, the attenuation ratio associated with different lines can be reconfirmed, thereby making specific corrections and adjustments to the signal waveform associated with the specified monitoring node, and thus completing the specific construction of the corresponding corrected waveform.

[0058] Based on the specific processing steps, the location features corresponding to different related points can be quickly identified. Then, based on the location features corresponding to several different related points, the accurate location of the fault point can be quickly identified, achieving a better location identification effect.

[0059] Some of the data in the above formulas are numerical calculations with dimensions removed, and the contents not described in detail in this specification are all prior art known to those skilled in the art.

[0060] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. An improved method for traveling wave ranging in distribution network fault location analysis, characterized in that, Includes the following steps: Step 1: Confirm the time of the transient traveling wave signal received by the monitoring nodes on both sides of the power distribution network transmission line, and based on the confirmed time difference, confirm and mark the line range where the fault point is located. Step 2: Based on the signal waveforms associated with the transient traveling wave signals received by the monitoring nodes on both sides, perform synchronous verification on the two sets of signal waveforms, lock the optimal verification process from the synchronous verification process, and lock the associated time difference from the optimal verification process. Step 3: Based on the determined associated time difference and line range, re-verify the associated time difference between the monitoring nodes on both sides, and confirm the accurate location of the fault point based on the specific verification process. Step 4: Randomly select associated points within the line range, and confirm the attenuation ratio based on the selected associated points and the specific line lengths on both sides. Then, based on the confirmed attenuation ratio, correct the signal waveforms associated with the monitoring nodes on both sides, and then re-verify the two sets of corrected signal waveforms to pinpoint the exact location of the fault.

2. The improved traveling wave ranging method for distribution network fault location analysis according to claim 1, characterized in that, In step one, the specific method for defining the range of the fault point is as follows: Based on the generated transient traveling wave signal, the reception times T1 and T2 associated with the monitoring nodes on both sides of the corresponding transmission line receiving such transient traveling wave signal are confirmed, where T1 and T2 represent different reception times associated with different monitoring nodes. The time difference Ct between the two sets of receiving times is determined by Ct = |T1-T2|. Based on the set transmission speed v, the value difference between the two transmission line segments is determined, and the value difference = Ct × v, where v is a preset value. From the receiving times T1 and T2, select the minimum value and record the monitoring node associated with the minimum value as the low node. Then, record another set of monitoring nodes as the high node. Randomly select a set of line nodes from the transmission line and record the line length L1 from the line node to the low node and the line length L2 from the line node to the high node. By adjusting the position of the line nodes, ensure that (L2-L1) = value difference. Based on the identified line nodes, use these line nodes as the center point to confirm left and right sides, and lock down the line range where a set of fault points are located.

3. The improved traveling wave ranging method for distribution network fault location analysis according to claim 2, characterized in that, When confirming the left and right sides of the line node, the confirmed distance value is 2m.

4. The improved traveling wave ranging method for distribution network fault location analysis according to claim 1, characterized in that, In step two, the specific method for locking the associated time difference is as follows: The transient traveling wave signals associated with the monitoring nodes on both sides are confirmed, and the two confirmed signal waveforms are checked for overlap. The two signal waveforms are placed in the same two-dimensional plane, with the horizontal axis representing the time line and the vertical axis representing the amplitude. The two signal waveforms are controlled to be translated left and right. During the translation control process, the amplitude difference generated when the two signal waveforms are at the same moment is recorded, and the amplitude difference is ≥0. The amplitude difference of several confirmed amplitude differences is averaged to confirm the characteristic mean associated with the corresponding translation process. The mean values ​​of different features associated with different translation processes are confirmed, and the minimum value is selected from the confirmed mean values ​​of different features. The translation process associated with the minimum value is recorded as the optimal verification process. The time difference between the starting points of the two sets of signal waveforms in the optimal verification process is confirmed to be ≥0, and the determined time difference is taken as the determined associated time difference.

5. An improved traveling wave ranging method for distribution network fault location analysis according to claim 1, characterized in that, In step three, the specific method for re-verifying the monitoring nodes on both sides is as follows: Based on the confirmed reception times T1 and T2 and the associated time difference, the reception times associated with the monitoring nodes on both sides are readjusted to Z1 and Z2. Based on the adjusted Z1 and Z2, the line nodes are re-marked within the transmission line using the method of re-determining the line nodes in step one, and recorded as sub-nodes. It is then identified whether the sub-nodes are located within the line range. If so, the location of the sub-node is recorded as the accurate location of the fault point and displayed. If not, subsequent steps are performed to reconfirm the accurate location of the fault point.

6. An improved traveling wave ranging method for distribution network fault location analysis according to claim 5, characterized in that, The specific method for readjusting the receiving time is as follows: The confirmed associated time difference is denoted as t1. It is confirmed that the reception time associated with the signal waveform that starts earlier remains unchanged, while the reception time associated with the signal waveform that starts later is postponed by t1.

7. An improved traveling wave ranging method for fault location analysis in a distribution network according to claim 1, characterized in that, In step four, the specific method for correcting the signal waveform is as follows: Based on the confirmed line range, a related point is randomly selected within this range, and based on the location of the related point, the distance of this related point from the line associated with the monitoring nodes on both sides is confirmed and recorded as C1 and C2 respectively. use: Confirm the attenuation energy E1 associated with line length C1, where Eo is the preset original energy, e is the base of the natural logarithm, and a is the preset attenuation coefficient. Use B1 = (E1 ÷ Eo) to confirm the attenuation ratio B1 associated with the corresponding line. Then, the same processing method is used to confirm the attenuation ratio B2 associated with line thread C2; Based on the confirmed attenuation ratios B1 and B2, the monitoring nodes associated with the corresponding lines are identified. The signal waveform associated with the monitoring nodes is adjusted in reverse to increase the amplitude associated with the signal waveform, resulting in an increased corrected waveform. This corrected waveform, under attenuation conditions B1 or B2, becomes the signal waveform associated with the corresponding monitoring node.

8. An improved traveling wave ranging method for fault location analysis in a distribution network according to claim 7, characterized in that, In step four, the specific method for accurately locating the fault point is as follows: The two sets of corrected waveforms are translated left and right in the same two-dimensional plane. The amplitude difference between the two sets of corrected waveforms at the same moment is recorded, and the amplitude difference is ≥0. The amplitude difference of the confirmed sets of amplitude differences is averaged to confirm the characteristic mean associated with the corresponding translation process. The mean values ​​of different features associated with different translation processes are confirmed, and the minimum value is selected from the confirmed mean values ​​of different features. The optimal verification process is determined, and the associated time difference of the two sets of corrected waveforms is locked. Based on the same processing method as in step three, it is confirmed whether the currently confirmed fault point is located within the line range. If so, the confirmed fault point is marked as a point to be selected. If not, no marking is performed. Based on the determination process of different correlation points, the determination process of several different candidate points can be completed, and the minimum value associated with different candidate points can be labeled as ZX. k Where k represents different points to be selected, and ZX is selected. k The point to be selected associated with min is recorded as the accurate location point, and based on the confirmed accurate location point, it is marked in the corresponding transmission line.

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