A distribution line traveling wave positioning method based on the fusion of zero mode and line mode traveling waves

Abstract

The present invention provides a method for locating a distribution line traveling wave based on the fusion of zero-mode and line-mode traveling waves. First, a distribution line description equation for fault location is constructed; then, the time t1 when the zero-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t2 when it reaches the end node are obtained, and the time t3 when the line-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t4 when it reaches the end node are obtained; again, according to t1, t2, and t3, t4, the section where the fault occurs is determined; finally, according to the determined section where the fault occurs, and the time difference t1-t3 and the time difference t2-t4, the fault position is finally determined. The present invention can realize fault location by using only two traveling wave sensors at the starting node and the end node of the distribution line, avoiding the branch line from affecting the accuracy of the traveling wave location of the distribution line, and also avoiding the installation of traveling wave sensors at the end of the branch line.

Description

Technical Field

[0001] The invention relates to the technical field of distribution network relay protection, and in particular to a distribution line traveling wave positioning method based on the fusion of zero mode and line mode traveling waves. Background Art

[0002] At present, the penetration rate of distributed renewable energy continues to increase, electric vehicles are widely connected, and time-varying loads are developing rapidly. The distribution network is showing complex source-grid-load-storage coordinated operation characteristics. In this context, once a distribution network with multiple branches and complex topology fails, the distribution characteristics of traditional power frequency voltage and power frequency current components are extremely complex and changeable. It is difficult for operation and maintenance personnel to determine the location of the fault in time, which affects the troubleshooting and power supply restoration process of on-site operation and maintenance personnel, resulting in a decrease in the level of power supply reliability.

[0003] The traveling wave fault location method uses the time difference between the high-frequency transient traveling wave head generated by the fault and the traveling wave sensor to achieve fault location. It has been widely used in high-voltage transmission networks. Since there are few branch lines in the AC line between two substations in the high-voltage transmission network, and new energy equipment is rarely connected to the line, the traveling wave arrival time difference recorded by the traveling wave sensors installed in the substations at both ends of the AC line can quickly achieve fault location. However, the distribution line has many branches and a complex topological structure. If traveling wave sensors are installed at the starting section and the end of the distribution line, the inferred fault location results are not unique. The inferred fault may occur on the trunk line or on the branch line. If traveling wave sensors are installed at the starting section, the end, the branch point, and the end of the branch line of the distribution line, the fault location can be uniquely located, but the economic cost is too high and cannot be promoted on a large scale. Summary of the invention

[0004] The purpose of the present invention is to provide a distribution line traveling wave fault location method based on the fusion of zero mode and line mode traveling waves in order to solve the above problems in the prior art.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for locating a distribution line traveling wave fault based on the fusion of zero mode and line mode traveling waves, comprising the following steps in sequence:

[0007] Step A: construct a distribution line description equation for fault location;

[0008] Step B, using the traveling wave sensors installed at the starting node and the terminal node of the distribution line, obtaining the time t1 when the zero-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t2 when it arrives at the terminal node, and obtaining the time t3 when the line-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t4 when it arrives at the terminal node;

[0009] Step C, according to the time t1 when the zero-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t2 when the end node reaches the end node, and the time t3 when the line-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t4 when the end node reaches the end node, combined with the distribution line description equation for fault location obtained in step A, determine the section where the fault occurs;

[0010] Step D, based on the fault section determined in step C, as well as the time difference t1-t3 between the zero-mode and line-mode traveling waves generated by the fault and their arrival at the starting node of the distribution line, and the time difference t2-t4 between the zero-mode and line-mode traveling waves and their arrival at the end node of the distribution line, the fault location is finally determined.

[0011] Furthermore, the distribution line is divided into two types: trunk line and branch line. The starting end, terminal end, branch node and branch line terminal node are numbered: M1 represents the starting end node of the distribution line, M2 represents the terminal node of the distribution line, and the branch nodes are numbered in sequence from the starting end node to the terminal node, and are numbered P1, P2, P3, ..., P N-1 , and branch points P1, P2, P3, ..., P N-1 The corresponding branch line terminal nodes are numbered F1, F2, F3, ..., F N-1 , when the numbering is satisfied in, Indicates the N-1th branch node P N-1 The distance to the end node M2 ​​of the distribution line, Indicates the N-1th branch node P N-1 To the N-1th branch node P N-1 Connected branch line end node F N-1 The distance Indicates the distance from the first branch node P1 to the starting node M1 of the distribution line, It represents the distance from the first branch node P1 to the end node F1 of the branch line connected to the first branch node P1. The line segment is defined as the line between any two adjacent branch nodes, or any branch line, or the line from the starting node of the line to the first branch node, or the line from the last branch node to the end node of the line. l xy represents the length of the section line with two end nodes x and y respectively, then the length from the starting end node of the distribution line to the mth node P m The shortest distance calculation formula is:

[0012] The fault traveling wave is transmitted along the shortest distance path between two nodes. Therefore, the distribution line description equation for fault location constructed in step A is a set of calculation formulas for the shortest distance from the actual end node of the distribution line to all trunk line nodes, which are as follows:

[0013]

[0014] Furthermore, in step C, determining the section where the fault occurs specifically includes the following steps:

[0015] Step C1-1, determine the distance l between the fault location and the starting node of the distribution line according to the time t1 when the zero-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t2 when the end node reaches the fault location. f1 , as follows:

[0016]

[0017] Where: l t is the length of the main line of the distribution line, and the calculation formula is δ1 is the undetermined length variable in zero-mode traveling wave positioning, which needs to be determined by the positioning formula in the subsequent step D; v0 is the zero-mode traveling wave velocity of the distribution line;

[0018] Step C1-2: Determine the distance l between the fault location and the starting node of the distribution line according to the time t3 when the line mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t4 when the end node reaches the end node. f2 , as follows:

[0019]

[0020] Where: δ2 is the length variable to be determined, which needs to be determined by the positioning formula in the subsequent step D; v1 is the traveling wave speed of the distribution line mode;

[0021] Step C1-3: The distance l between the fault location obtained in step C1-1 and the node at the starting end of the distribution line f1 , combined with the distribution line description equation for fault location obtained in step A, the fault section is calculated based on the time information when the zero-mode traveling wave arrives at the starting node and the end node of the distribution line:

[0022] like and The fault occurs at the kth branch node P k and the k+1th branch node P k+1 In this section, β1 is the fault section location judgment threshold, which is determined by the traveling wave sensor head moment calibration error and algorithm error;

[0023] like There are three situations in which the fault occurs: (1) The kth branch node P k and the k+1th branch node P k+1 This section; (2) the k-1th branch node Pk-1 With the kth branch node P k This segment; (3) and the kth branch node P k On the connected branch line; step C1-4, the distance l between the fault location and the starting node of the distribution line obtained according to step C1-2 f2 , combined with the distribution line description equation for fault location obtained in step A, the fault section is calculated based on the time information when the line mode traveling wave arrives at the starting node and the end node of the distribution line:

[0024] like and Then it is finally determined that the fault occurs at the kth branch node P k and the k+1th branch node P k+1 In this section, β 11 The threshold for determining the line mode traveling wave location in the fault section is determined by the traveling wave sensor head moment calibration error and the algorithm error.

[0025] like There are three situations in which the fault occurs: (1) The kth branch node P k and the k+1th branch node P k+1 This section; (2) the k-1th branch node P k-1 With the kth branch node P k This segment; (3) and the kth branch node P k connected branch lines.

[0026] Further, in step D, the fault location is finally determined according to the fault occurrence section determined in step C, the time difference t1-t3 between the zero mode and line mode traveling waves generated by the fault and the time difference t2-t4 between the zero mode and line mode traveling waves and the terminal node of the distribution line. The specific steps include the following:

[0027] Step D1-1, calculate the distance l between the fault location and the distribution line starting node according to the time difference t1-t3 between the zero mode and line mode traveling waves generated by the fault and the node at the starting end of the distribution line. f3 :

[0028]

[0029] Step D1-2: Determine the fault location by combining the fault section determined in step C, as follows:

[0030] (1) If and β2 is the error threshold, then the fault location is at the kth branch node P k and the k+1th branch node P k+1This section is located at a distance from the kth branch node P k The distance is

[0031] (2) If and β3 is the threshold set to avoid misjudgment; the fault location is at the kth branch node P k On the connected branch line, and the distance from the kth branch node P k The distance is

[0032] (3) If none of the above conditions are met, the fault location is at the kth branch node P k On the surrounding lines, with P k The distance is less than 1km.

[0033] Furthermore, the fault section location determination threshold β1 is set to 0.6 km.

[0034] Furthermore, the fault section line mode traveling wave location judgment threshold β 11 Take it as 0.5km.

[0035] Furthermore, the error threshold β2 is set to 0.5 km.

[0036] Furthermore, the threshold β3 set to avoid misjudgment is set to 1.0 km.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The present invention uses traveling wave sensors installed at the starting node and the terminal node of the distribution line to obtain the time t1 when the zero-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t2 when it arrives at the terminal node, and obtains the time t3 when the line-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t4 when it arrives at the terminal node, and then uses the difference between the four time points to determine the fault occurrence section and the distance between the fault location and the starting node of the distribution line. Finally, according to the description equation of the distribution line, the fault location is uniquely determined, and the fault location can be realized by using only two traveling wave sensors at the starting node and the terminal node of the distribution line, thereby avoiding the branch line from affecting the accuracy of the traveling wave location of the distribution line, and also avoiding the installation of a traveling wave sensor at the end of the branch line;

[0039] 2. The present invention makes full use of the different wave speeds of zero-mode and line-mode traveling waves generated by distribution line faults, and respectively captures the moment when the zero-mode traveling wave and line-mode traveling wave generated by the fault first arrive at the traveling wave sensor to complete the fault location, avoiding the problem of difficult wave head identification caused by subsequent refraction and reflection, and can effectively improve the accuracy and reliability of traveling wave positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A flow chart of a method for locating a traveling wave fault in a distribution line based on the fusion of zero-mode and line-mode traveling waves is provided for an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of a power distribution network line fault according to an embodiment of the present invention;

[0042] Figure 3 Determine the line topology diagram of a typical distribution network in the section where the fault occurs. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] See also Figure 1 The embodiment of the present invention provides a method for locating a distribution line traveling wave fault based on the fusion of zero mode and line mode traveling waves, comprising the following steps:

[0045] Step A: construct a distribution line description equation for fault location;

[0046] Step B, using the traveling wave sensors installed at the starting node and the terminal node of the distribution line, obtaining the time t1 when the zero-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t2 when it arrives at the terminal node, and obtaining the time t3 when the line-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t4 when it arrives at the terminal node;

[0047] Step C, according to the time t1 when the zero-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t2 when the end node reaches the end node, and the time t3 when the line-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t4 when the end node reaches the end node, combined with the distribution line description equation for fault location obtained in step A, determine the section where the fault occurs.

[0048] Step D, based on the fault section determined in step C, as well as the time difference t1-t3 between the zero-mode and line-mode traveling waves generated by the fault and their arrival at the starting node of the distribution line, and the time difference t2-t4 between the zero-mode and line-mode traveling waves and their arrival at the end node of the distribution line, the fault location is finally determined.

[0049] In step A, the distribution line description equation for fault location is constructed as follows:

[0050] Distribution lines are divided into two types: trunk lines and branch lines. The starting end, end, branch node, and branch line end node are numbered. M1 represents the starting end node of the distribution line, M2 represents the end node of the distribution line, and the branch nodes are numbered in order from the starting end node to the end node, and are numbered P1, P2, P3, ..., P N-1 , and branch points P1, P2, P3, ..., P N-1 The corresponding branch line terminal nodes are numbered F1, F2, F3, ..., F N-1 . When numbering satisfies l PN-1M2 ≥l PN-1FN-1 , l P1M1 ≥l P1F1 Among them, l PN-1M2 Indicates the N-1th branch node P N-1 Distance to the end node M2 ​​of the distribution line, l PN-1FN-1 Indicates the N-1th branch node P N-1 To the N-1th branch node P N-1 Connected branch line end node F N-1 The distance. P1M1 represents the distance from the first branch node P1 to the starting node M1 of the distribution line, l P1F1 Indicates the distance from the first branch node P1 to the branch line end node F1 connected to the first branch node P1. Define the line segment as the line between any two adjacent branch nodes, or any branch line, or the line from the line start node to the first branch node, or the line from the last branch node to the line end node. xy Indicates the length of the segment line whose end nodes are x and y respectively.

[0051] Then the distribution line starting node to the mth node P m The shortest distance calculation formula is:

[0052] The fault traveling wave is transmitted along the shortest distance path between two nodes. Therefore, the distribution line description equation for fault location constructed in step A is a set of calculation formulas for the shortest distance from the actual end node of the distribution line to all trunk line nodes, which are as follows:

[0053]

[0054] In step C, determining the section where the fault occurs specifically includes the following steps:

[0055] Step C1-1, determine the distance l between the fault location and the starting node of the distribution line according to the time t1 when the zero-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t2 when the end node reaches the fault location.f1 , as follows:

[0056]

[0057] Where: l t is the length of the main line of the distribution line, and the calculation formula is δ1 is the undetermined length variable in zero-mode traveling wave positioning, which needs to be determined by the positioning formula in the subsequent step D; v0 is the zero-mode traveling wave velocity of the distribution line, which is generally obtained based on line parameter theory or on-site measurement.

[0058] Step C1-2: Determine the distance l between the fault location and the starting node of the distribution line according to the time t3 when the line mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t4 when the end node reaches the end node. f2 , as follows:

[0059]

[0060] Where: δ2 is the unknown length variable, which needs to be determined by the positioning formula in the subsequent step D; v1 is the traveling wave velocity of the distribution line line mode, which is generally obtained based on line parameter theory or on-site measurement.

[0061] Step C1-3: The distance l between the fault location obtained in step C1-1 and the node at the starting end of the distribution line f1 , combined with the distribution line description equation for fault location obtained in step A, the fault section is calculated based on the time information when the zero-mode traveling wave arrives at the starting node and the end node of the distribution line,

[0062] like and The fault occurs at the kth branch node P k and the k+1th branch node P k+1 In this section, β1 is the fault section location judgment threshold, which is mainly determined by the traveling wave sensor head time calibration error and algorithm error, and can generally be taken as 0.6 km.

[0063] like The fault section may have three situations: (1) The kth branch node P k and the k+1th branch node P k+1 This section; (2) the k-1th branch node P k-1 With the kth branch node P k This segment; (3) and the kth branch node P k connected branch lines.

[0064] Step C1-4: The distance l between the fault location obtained in step C1-2 and the node at the starting end of the distribution linef2 , combined with the distribution line description equation for fault location obtained in step A, the fault section is calculated based on the time information when the line mode traveling wave arrives at the starting node and the end node of the distribution line:

[0065] like and Then it is finally determined that the fault occurs at the kth branch node P k and the k+1th branch node P k+1 In this section, β 11 is the line mode traveling wave positioning judgment threshold of the fault section, which is mainly determined by the traveling wave sensor head moment calibration error and algorithm error, and can generally be taken as 0.5km.

[0066] like The fault section may have three situations: (1) The kth branch node P k and the k+1th branch node P k+1 This section; (2) the k-1th branch node P k-1 With the kth branch node P k This segment; (3) and the kth branch node P k The specific fault section needs to be further determined in conjunction with subsequent steps.

[0067] In step D, the fault location is finally determined based on the fault occurrence section determined in step C, the time difference t1-t3 between the zero mode and line mode traveling waves generated by the fault and the time difference t2-t4 between the zero mode and line mode traveling waves and the terminal node of the distribution line. Specifically, it includes the following:

[0068] Step D1-1, calculate the distance l between the fault location and the distribution line starting node according to the time difference t1-t3 between the zero mode and line mode traveling waves generated by the fault and the node at the starting end of the distribution line. f3 :

[0069]

[0070] Step D1-2: Determine the fault location by combining the fault section determined in step C, as follows:

[0071] (1) If and β2 is the error threshold due to measurement, etc., which can generally be taken as 0.5 km. The fault location is at the kth branch node P k and the k+1th branch node P k+1 This section is located at a distance from the kth branch node P k The distance is

[0072] (2) If and The threshold set to avoid misjudgment is generally 1.0 km. Then the fault location is at the kth branch node P k On the connected branch line, and the distance from the kth branch node P k The distance is

[0073] (3) If none of the above conditions are met, the fault location is at the kth branch node P k On the surrounding lines, with P k The distance is less than 1km.

[0074] The following is an explanation with a specific example:

[0075] The distribution line traveling wave fault location method based on the fusion of zero mode and line mode traveling waves is Figure 1 The steps given are to troubleshoot, Figure 2 A typical distribution line fault situation is given.

[0076] for Figure 3 For specific distribution lines:

[0077] (1) First, construct the distribution line description equation for fault location. The starting node and the end node of the distribution line are M1 and M2, the branch nodes are P1 and P2, the end node of the branch line connected to the branch node P1 is F1, and the end node of the branch line connected to the branch node P2 is F2. Then l M1P1 =15km, l P1P2 =8km, l P2M2 =11km, l P1F1 =10km, l P2F2 =8km.

[0078] (2) Using traveling wave sensors installed at the starting and ending nodes of the distribution line, the time t1 = 5 minutes 41 seconds 92.1 microseconds when the zero-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t2 = 5 minutes 41 seconds 109.6 microseconds when it arrives at the ending node are obtained; the time t3 = 5 minutes 41 seconds 71.2 microseconds when the line-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t4 = 5 minutes 41 seconds 84.7 microseconds when it arrives at the ending node are obtained.

[0079] (3) According to the time t1 when the zero-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t2 when the end node arrives, and the time t3 when the line-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t4 when the end node arrives, the section where the fault occurs is determined. Where v0 = 2.28 × 10 8m / s, v1=2.95×10 8 m / s.

[0080] because Therefore, there are three possible sections where the fault occurs: (1) the section between the first branch node P1 and the second branch node P2; (2) the section between the line starting node and the first branch node P1; (3) the branch line connected to the first branch node P1.

[0081] (4) The fault location is finally determined based on the fault section determined in step C, the time difference t1-t3 between the zero-mode and line-mode traveling waves generated by the fault and their arrival at the starting node of the distribution line, and the time difference t2-t4 between the zero-mode and line-mode traveling waves generated by the fault and their arrival at the end node of the distribution line.

[0082]

[0083] Therefore, the fault location is on the branch line connected to the first branch node P1, and the distance from the first branch node P1 is l f3 -l P1M1 =5.981km.

[0084] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A distribution line traveling wave fault location method based on the fusion of zero mode and line mode traveling waves, characterized in that The steps include: Step A: construct a distribution line description equation for fault location; Step B, using the traveling wave sensors installed at the starting node and the terminal node of the distribution line, obtaining the time t1 when the zero-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t2 when it arrives at the terminal node, and obtaining the time t3 when the line-mode traveling wave generated by the fault arrives at the starting node of the distribution line and the time t4 when it arrives at the terminal node; Step C, according to the time t1 when the zero-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t2 when the end node reaches the end node, and the time t3 when the line-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t4 when the end node reaches the end node, combined with the distribution line description equation for fault location obtained in step A, determine the section where the fault occurs; Step D, finally determine the fault location according to the fault occurrence section determined in step C, the time difference t1-t3 between the zero mode and line mode traveling waves generated by the fault and the time difference t2-t4 between the zero mode and line mode traveling waves and the terminal node of the distribution line; In step C, determining the section where the fault occurs specifically includes the following steps: Step C1-1, determine the distance l between the fault location and the starting node of the distribution line according to the time t1 when the zero-mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t2 when the end node reaches the fault location. f1 , as follows: Where: l t is the length of the main line of the distribution line, and the calculation formula is: δ1 is the undetermined length variable in zero-mode traveling wave positioning, which needs to be determined by the positioning formula in the subsequent step D; v0 is the zero-mode traveling wave velocity of the distribution line; Step C1-2: Determine the distance l between the fault location and the starting node of the distribution line according to the time t3 when the line mode traveling wave generated by the fault reaches the starting node of the distribution line and the time t4 when the end node reaches the end node. f2 , as follows: Where: δ2 is the length variable to be determined, which needs to be determined by the positioning formula in the subsequent step D; v1 is the traveling wave speed of the distribution line mode; Step C1-3: The distance l between the fault location obtained in step C1-1 and the node at the start end of the distribution line f1 , combined with the distribution line description equation for fault location obtained in step A, the fault section is calculated based on the time information when the zero-mode traveling wave arrives at the starting node and the end node of the distribution line: like and The fault occurs at the kth branch node P k and the k+1th branch node P k+1 In this section, β1 is the fault section location judgment threshold, which is determined by the traveling wave sensor head moment calibration error and algorithm error; like There are three situations in which the fault occurs: (1) The kth branch node P k and the k+1th branch node P k+1 This section; (2) the k-1th branch node P k-1 With the kth branch node P k This segment; (3) and the kth branch node P k On the connected branch line; step C1-4, the distance l between the fault location and the starting node of the distribution line obtained according to step C1-2 f2 , combined with the distribution line description equation for fault location obtained in step A, the fault section is calculated based on the time information when the line mode traveling wave arrives at the starting node and the end node of the distribution line: like and Then it is finally determined that the fault occurs at the kth branch node P k and the k+1th branch node P k+1 In this section, β 11 The threshold for determining the line mode traveling wave location in the fault section is determined by the traveling wave sensor head moment calibration error and the algorithm error. like There are three situations in which the fault occurs: (1) The kth branch node P k and the k+1th branch node P k+1 This section; (2) the k-1th branch node P k-1 With the kth branch node P k This segment; (3) and the kth branch node P k On the connected branch lines; In step D, the fault location is finally determined according to the fault occurrence section determined in step C, the time difference t1-t3 between the zero mode and line mode traveling waves generated by the fault and the time difference t2-t4 between the zero mode and line mode traveling waves and the terminal node of the distribution line. The specific steps include the following: Step D1-1, calculate the distance l between the fault location and the distribution line starting node according to the time difference t1-t3 between the zero mode and line mode traveling waves generated by the fault and the node at the starting end of the distribution line. f3 : Step D1-2: Determine the fault location by combining the fault section determined in step C, as follows: (1) If and β2 is the error threshold, then the fault location is at the kth branch node P k and the k+1th branch node P k+1 This section is located at a distance from the kth branch node P k The distance is (2) If and β3 is the threshold set to avoid misjudgment; the fault location is at the kth branch node P k On the connected branch line, and the distance from the kth branch node P k The distance is (3) If none of the above conditions are met, the fault location is at the kth branch node P k On the surrounding lines, with P k The distance is less than 1km.

2. According to claim 1, a method for locating a distribution line traveling wave fault based on the fusion of zero mode and line mode traveling waves, characterized in that: The distribution lines are divided into two types: trunk lines and branch lines. The starting end, end, branch node and branch line end node are numbered: M1 represents the starting end node of the distribution line, M2 represents the end node of the distribution line, and the branch nodes are numbered in sequence from the starting end node to the end node, and are numbered P1, P2, P3, ..., P N-1 , and branch points P1, P2, P3, ..., P N-1 The corresponding branch line terminal nodes are numbered F1, F2, F3, ..., F N-1 , when the numbering is satisfied in, Indicates the N-1th branch node P N-1 The distance to the end node M2 ​​of the distribution line, Indicates the N-1th branch node P N-1 To the N-1th branch node P N-1 Connected branch line end node F N-1 The distance Indicates the distance from the first branch node P1 to the starting node M1 of the distribution line, It represents the distance from the first branch node P1 to the end node F1 of the branch line connected to the first branch node P1. The line segment is defined as the line between any two adjacent branch nodes, or any branch line, or the line from the starting node of the line to the first branch node, or the line from the last branch node to the end node of the line. l xy represents the length of the section line with two end nodes x and y respectively, then the length from the starting end node of the distribution line to the mth node P m The shortest distance calculation formula is: The fault traveling wave is transmitted along the shortest distance path between two nodes. Therefore, the distribution line description equation for fault location constructed in step A is a set of calculation formulas for the shortest distance from the actual end node of the distribution line to all trunk line nodes, which are as follows:

3. The method for locating a distribution line traveling wave fault based on the fusion of zero mode and line mode traveling waves according to claim 1, characterized in that: The fault section location judgment threshold β1 is set to 0.6 km.

4. The method for locating a distribution line traveling wave fault based on the fusion of zero mode and line mode traveling waves according to claim 1, characterized in that: The fault section line mode traveling wave location judgment threshold β 11 Take it as 0.5km.

5. The method for locating a distribution line traveling wave fault based on the fusion of zero mode and line mode traveling waves according to claim 1, characterized in that: The error threshold β2 is set to 0.5 km.

6. The method for locating a distribution line traveling wave fault based on the fusion of zero mode and line mode traveling waves according to claim 1, characterized in that: The threshold β3 set to avoid erroneous judgment is set to 1.0 km.

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