A method for active power distribution network fault location based on correction matrix algorithm

Abstract

The application relates to an active power distribution network fault positioning method based on a correction matrix algorithm. First, based on the topological connection relationship of a power distribution network and the fault overcurrent information uploaded by feeder terminal units (FTUs), a network description matrix and a fault information matrix are constructed, and a fault judgment matrix is calculated; second, if the information uploaded by the two sub-node FTUs of a T-connection section in the power distribution network is different, the fault judgment matrix is corrected; finally, a fault positioning criterion is used to position the fault section. The application can effectively avoid the fault positioning misjudgment caused by the T-connection section.

Description

Technical Field

[0001] This invention relates to the field of power system dispatch automation technology, and in particular to an active distribution network fault location method based on a correction matrix algorithm. Background Technology

[0002] The distribution network is the part of the power system directly connected to the electrical loads. Accurately locating and isolating faulty sections during short-circuit faults is crucial for improving the reliability of power supply from the distribution network. Currently, with the rapid development of distributed generation technology, more and more distributed generation (DG) sources are being connected to the distribution network, transforming it from a single-source radial network into a complex multi-source network. Distribution networks containing DG have complex structures and bidirectional power flow, rendering traditional fault location methods ineffective. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a fault location method for active distribution networks based on a correction matrix algorithm. First, the FTU that uploads fault information must be able to detect the direction of the fault overcurrent. When a short-circuit fault occurs in a distribution network containing distributed generation (DG), it can upload three types of information (-1, 0, 1) representing the direction of the node overcurrent. Based on the distribution network topology and the fault overcurrent information uploaded by the feeder terminal units (FTUs), a network description matrix and a fault information matrix are constructed, and a fault judgment matrix is ​​calculated. Second, if the information uploaded by the two sub-node FTUs in a T-connection section of the distribution network is different, the fault judgment matrix is ​​corrected. Finally, the fault location criteria are used to locate the fault section.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: an active distribution network fault location method based on a correction matrix algorithm, comprising the following steps:

[0005] Step S1: Based on the topological connection relationship of each node in the distribution network and the fault information uploaded by the FTU, form a network description matrix D and a fault information matrix G. Add the two matrices together to obtain the fault judgment matrix P.

[0006] Step S2: Analyze the elements in the first row of the fault judgment matrix to determine whether there are nodes that constitute a T-junction segment;

[0007] Step S3: Based on the judgment in step S2, if there are no nodes that constitute a T-junction section, the status of the feeder section is directly determined using the fault location criteria.

[0008] Step S4: Based on the judgment in step S2, if there are nodes that constitute a T-junction segment and the FTUs of the two child nodes upload the same information, the status of the T-junction segment is directly determined using the fault location criteria.

[0009] Step S5: Based on the judgment in step S2, if there are nodes that constitute a T-junction segment and the FTU of the two child nodes upload different information, first correct the relevant diagonal elements of the fault judgment matrix, and then use the fault location criteria to determine the status of the T-junction segment.

[0010] Step S6: Restore the corrected diagonal element values ​​in the fault judgment matrix;

[0011] Step S7: Analyze the status of all feeder sections according to steps S2 to S6.

[0012] In a preferred embodiment, in step S1, the FTU that uploads fault information is equipped with a device to detect the direction of the fault overcurrent. When a short-circuit fault occurs in a distribution network containing distributed generation (DG), the directions of the fault overcurrent provided by the system's main power supply and the downstream DG at the fault point are opposite. To distinguish the above-mentioned fault overcurrent directions to adapt to the fault location of the distribution network under the condition of DG access, the direction from the system's main power supply to the end of the feeder or the DG is defined as the positive direction of the entire network. Each FTU in the distribution network containing DG is set with three working modes: "-1, 0, 1" according to whether it detects the fault overcurrent and whether its direction is consistent with the positive direction of the entire network. If an FTU detects the fault overcurrent and its direction is consistent with the positive direction of the entire network, the FTU uploads information "1" to the control master station. If an FTU detects the fault overcurrent and its direction is opposite to the positive direction of the entire network, it uploads "-1". If an FTU does not detect the fault overcurrent, it uploads "0".

[0013] In a preferred embodiment, in step S1, a network description matrix D is formed based on the topological connection relationship of each node in the distribution network. The switches in the distribution network containing distributed generation DG include substation outgoing switches, sectionalizing switches and tie switches. According to graph theory, the entire 10kV distribution network is regarded as a tree structure, and the substation outgoing switches, sectionalizing switches and tie switches are regarded as nodes.

[0014] The network description matrix D is a square matrix with a dimension equal to the total number of nodes in the distribution network. A node tree is constructed using all switches on the 10kV line, starting from the substation outgoing switch and numbered from smallest to largest along the main line. In a section, the node with the smallest number is the parent node, and the rest are child nodes. If node i and node j are the parent and child nodes of a feeder section, respectively, set the off-diagonal element d in matrix D. ij =1; otherwise, set it to 0; the network description matrix D is constructed according to the following rules:

[0015]

[0016] In a preferred embodiment, in step S1, a diagonal matrix—the fault information matrix G—of the same type as the network description matrix is ​​constructed based on the topological connection relationship of each node in the distribution network and the fault information uploaded by the FTUs. The diagonal elements are the information uploaded by each FTU in sequence. The construction rules of the fault information matrix are as follows:

[0017]

[0018] The network description matrix D and the fault information matrix G are added together to obtain the fault judgment matrix P. The off-diagonal elements of the fault judgment matrix P represent the topological connection relationship between each node in the distribution network, and its diagonal elements represent the fault overcurrent information detected by the FTU of each node.

[0019] In a preferred embodiment, in step S2, the analysis starts from the first row of the fault judgment matrix. Based on the off-diagonal elements of the first row, it is determined whether there are nodes that constitute a T-junction segment. If the next level tree structure of the parent node device has multiple child node devices, then a T-junction area is formed.

[0020] In a preferred embodiment, in step S3, if there are no nodes forming a T-junction section, the status of the feeder section is directly determined using the fault location criteria. If the overcurrent direction information uploaded by the parent and child FTU nodes of the feeder section is different, it indicates that the section has a fault; if the overcurrent direction information uploaded by the parent and child FTU nodes of the feeder section is the same, it indicates that the section has not a fault.

[0021] In a preferred embodiment, in step S4, there are nodes constituting a T-junction segment. The FTU information of the parent and child nodes of the feeder segment is used for determination. If the direction of the overcurrent information uploaded by all child node FTUs is the same and the direction of the overcurrent information uploaded by the parent node FTU is different, the status of the feeder segment is directly determined using the fault location criterion, indicating that the segment has a fault. If the direction of the overcurrent information uploaded by all child node FTUs is the same and the direction of the overcurrent information uploaded by the parent node FTU is the same, the status of the feeder segment is directly determined using the fault location criterion, indicating that the segment has not a fault.

[0022] In a preferred embodiment, in step S5, there are nodes constituting the T-junction section. The FTU information of the parent and child nodes of the feeder section is used for determination. If the directions of the overcurrent information uploaded by the child node FTU are different, the relevant diagonal elements of the fault judgment matrix are first corrected. Using the idea of ​​equivalence, under the premise that the state of the T-junction section remains unchanged, the overcurrent direction information uploaded by the two child node FTUs is corrected to be the same, that is, the corresponding diagonal elements of the fault judgment matrix are corrected. The correction principle is: if the overcurrent direction information uploaded by the two child node FTUs is different, as long as one is "1", both are corrected to "1"; if there is no "1", as long as one is "-1", both are corrected to "-1".

[0023] In step S5, there are nodes that constitute a T-junction segment. If the information uploaded by the child node FTU is different, after correction by the relevant diagonal elements of the fault judgment matrix, the state of the T-junction segment is determined by the fault location criterion. If the overcurrent direction information of the parent node and the child node is different, it indicates that the segment has a fault; if the information of the parent node and the child node is the same, it indicates that the segment has not a fault.

[0024] In a preferred embodiment, in step S6, it is not guaranteed that the fault status determination of all sections is based on the original data. After the determination is completed in step S5, the values ​​of the corrected diagonal elements in the fault determination matrix need to be restored.

[0025] In a preferred embodiment, in step S7, it is determined whether all N rows of the fault judgment matrix have been analyzed; if not, the analysis proceeds to step S2 to continue analyzing the next row; if the analysis is complete, all fault segments are output, and the fault location ends.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. Based on FTU information with current direction, the physical meaning is clear and the fault location accuracy is good.

[0028] 2. It can effectively avoid misdiagnosis of fault location that may be caused by T-junction sections, and has certain practical value. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the distribution network T according to a preferred embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of a tree structure according to a preferred embodiment of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application; as used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise; furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] A fault location method for active distribution networks based on a correction matrix algorithm includes the following steps:

[0035] Step S1: Based on the topological connection relationship of each node in the distribution network and the fault information uploaded by the FTU, form a network description matrix D and a fault information matrix G. Add the two matrices together to obtain the fault judgment matrix P.

[0036] Step S2: Analyze the elements in the first row of the fault judgment matrix to determine whether there are nodes that constitute a T-junction segment.

[0037] Step S3: Based on the judgment in step S2, if there are no nodes that constitute a T-connection section, the status of the feeder section is directly determined using the fault location criteria.

[0038] Step S4: Based on the judgment in step S2, if there are nodes that constitute a T-junction segment and the FTUs of the two child nodes upload the same information, the status of the T-junction segment is directly determined using the fault location criteria.

[0039] Step S5: Based on the judgment in step S2, if there are nodes that constitute a T-junction segment and the FTUs of the two child nodes upload different information, first correct the relevant diagonal elements of the fault judgment matrix, and then use the fault location criteria to determine the status of the T-junction segment.

[0040] Step S6: Restore the corrected diagonal element values ​​in the fault judgment matrix.

[0041] Step S7: Analyze the status of all feeder sections according to steps S2 to S6.

[0042] In step S1, the FTU that uploads fault information is equipped with a device to detect the direction of the fault overcurrent. When a short-circuit fault occurs in a distribution network containing distributed generation (DG), the fault overcurrent provided by the main power source of the system and the downstream DG at the fault point has opposite directions. To distinguish the above-mentioned fault overcurrent directions to adapt to the fault location of the distribution network under DG access, the direction from the main power source on the system side to the end of the feeder or the DG is defined as the positive direction of the entire network. Each FTU in the DG-containing distribution network is set to three working modes: "-1, 0, 1" according to whether it detects the fault overcurrent and whether its direction is consistent with the positive direction of the entire network. If an FTU detects the fault overcurrent and its direction is consistent with the positive direction of the entire network, the FTU uploads information "1" to the control master station; if an FTU detects the fault overcurrent and its direction is opposite to the positive direction of the entire network, it uploads "-1"; if an FTU does not detect the fault overcurrent, it uploads "0".

[0043] In step S1, a network description matrix D is formed based on the topological connections of each node in the distribution network. The switches in the distribution network containing DG include substation outgoing switches, sectionalizing switches, and tie switches. Based on graph theory, the entire 10kV distribution network is considered a tree structure, with substation outgoing switches, sectionalizing switches, and tie switches considered as nodes. Figure 2 As shown;

[0044] The network description matrix D is a square matrix with a dimension equal to the total number of nodes in the distribution network. A node tree is constructed using all switches on the 10kV line. Starting with the outgoing switches of the substation, nodes are numbered from smallest to largest along the main line. In a given section, the node with the smallest number is the parent node, and the rest are child nodes. If node i and node j are the parent and child nodes of a feeder section, respectively, the off-diagonal element dij in matrix D is set to 1; otherwise, it is set to 0. The construction rules for the network description matrix D are as follows:

[0045]

[0046] In step S1, a diagonal matrix—the fault information matrix G—of the same type as the network description matrix is ​​constructed based on the topological connection relationship of each node in the distribution network and the fault information uploaded by the FTUs. The diagonal elements are the information uploaded by each FTU in sequence. The construction rules of the fault information matrix are as follows:

[0047]

[0048] In step S1, the network description matrix D and the fault information matrix G are added together to obtain the fault judgment matrix P. The off-diagonal elements of the fault judgment matrix P represent the topological connection relationship between nodes in the distribution network; its diagonal elements represent the fault overcurrent information detected by the FTU of each node.

[0049] In step S2, the analysis starts from the first row of the fault judgment matrix. Based on the off-diagonal elements of the first row, it is determined whether there are nodes that constitute a T-junction segment. If the next level tree structure of the parent node device has multiple child node devices, then a T-junction area is formed.

[0050] In step S3, if there are no nodes forming a T-junction section, the status of the feeder section is directly determined using fault location criteria. If the overcurrent direction information uploaded by the parent and child FTU nodes of the feeder section is different, it indicates that a fault has occurred in that section. If the overcurrent direction information uploaded by the parent and child FTU nodes of the feeder section is the same, it indicates that no fault has occurred in that section.

[0051] In step S4, for nodes constituting a T-junction segment, the FTU information of the parent and child nodes of the feeder segment is used for determination. If the direction of the overcurrent information uploaded by all child node FTUs is the same, but different from the direction of the overcurrent information uploaded by the parent node FTU, the status of the feeder segment is directly determined using the fault location criterion, indicating that a fault has occurred in that segment. If the direction of the overcurrent information uploaded by all child node FTUs is the same, and different from the direction of the overcurrent information uploaded by the parent node FTU, the status of the feeder segment is directly determined using the fault location criterion, indicating that no fault has occurred in that segment.

[0052] In step S5, nodes constituting the T-junction section are used to determine the fault direction based on the FTU information of the parent and child nodes of the feeder section. If the directions of the overcurrent information uploaded by the child node FTUs are different, the relevant diagonal elements of the fault judgment matrix are first corrected. Using the concept of equivalence, under the premise that the state of the T-junction section remains unchanged, the overcurrent direction information uploaded by the two child node FTUs is corrected to be the same, that is, the corresponding diagonal elements of the fault judgment matrix are corrected. The correction principle is: if the overcurrent direction information uploaded by the two child node FTUs is different, as long as one is "1", both are corrected to "1"; if there is no "1", as long as one is "-1", both are corrected to "-1".

[0053] In step S5, there are nodes constituting a T-junction segment. If the FTU-uploaded information of the child nodes is different, after correction by the relevant diagonal elements of the fault judgment matrix, the state of the T-junction segment is determined using the fault location criteria. If the overcurrent direction information of the parent node and the child node is different, it indicates that a fault has occurred in the segment. If the information of the parent node and the child node is the same, it indicates that no fault has occurred in the segment.

[0054] In step S6, it is not guaranteed that the fault status determination of all sections is based on the original data. After the determination is completed in step S5, the values ​​of the corrected diagonal elements in the fault determination matrix need to be restored.

[0055] In step S7, it is determined whether all elements in row N of the fault judgment matrix have been analyzed. If not, proceed to step S2 to continue analyzing the next row; if the analysis is complete, output all fault segments, and the fault location ends.

[0056] The following is in conjunction with the appendix Figure 1 The technical solution of the present invention will be described in detail below, assuming that the figures in the accompanying drawings are... Figure 1 A short circuit fault occurred in the T-connection section (5) of the distribution network shown.

[0057] This invention provides an active power distribution network fault location method based on a correction matrix algorithm, comprising the following steps:

[0058] Step S1: Assuming the figure in the attached diagram Figure 1 A short-circuit fault occurred in the T-connection section (5) of the distribution network shown. The fault overcurrent information uploaded by each switch FTU is: [110010-1-1-1-1]. First, the network description matrix D is established as:

[0059]

[0060] The fault information matrix G is established as follows:

[0061]

[0062] The fault judgment matrix P is calculated as follows:

[0063]

[0064] Step S2: According to the fault judgment matrix P, the double-ended feeder section (1) is formed by nodes 1 and 2, the T-connection section (2) is formed by nodes 2, 3 and 5, the double-ended feeder section (3) is formed by nodes 3 and 4, and the T-connection section (5) is formed by nodes 5, 6 and 7.

[0065] Step S3: According to the fault judgment matrix P, p11=1, p12=1, p22=1, the double-ended feeder section (1) formed by nodes 1 and 2 is normal. p33=0, p34=1, p44=0, the double-ended feeder section (3) formed by nodes 3 and 4 is normal.

[0066] Step S4: p22=1, p23=p25=1, nodes 2, 3, and 5 constitute T-connection segment (2); p33=0, p55=1, the FTU upload information at the two child nodes 3 and 5 is different; p33=p55=1, the FTU upload information at the two child nodes 3 and 5 is corrected; p22=1, p23=1, p33=1, T-connection segment (2) is normal; p22=1, p25=1, p55=1, T-connection segment (2) is normal; considering the above, it can be concluded that T-connection segment (2) is normal.

[0067] Step S5: p55=1, p56=p57=1, nodes 5, 6, and 7 form a T-connection segment (5); p66=0, p77=-1, the FTU upload information at the two child nodes 6 and 7 is different, the FTU upload information at the two child nodes 6 and 7 is corrected, p66=p77=-1; p55=1, p56=1, p66=-1, T-connection segment (5) is faulty; p55=1, p57=1, p77=-1, T-connection segment (5) is faulty; considering the above, it can be concluded that T-connection segment (5) is faulty.

[0068] Step S6: Based on the improved matrix algorithm for fault location, the faulty section is determined to be the T-junction section (5) consisting of switches 5, 6, and 7.

[0069] The above are preferred embodiments of the present invention. Any changes made to the technical solution of the present invention that do not exceed the scope of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for fault location in active distribution networks based on a correction matrix algorithm, characterized in that, Includes the following steps: Step S1: Based on the topological connection relationship of each node in the distribution network and the fault information uploaded by the FTU, form a network description matrix D and a fault information matrix G. Add the two matrices together to obtain the fault judgment matrix P. Step S2: Analyze the elements in the first row of the fault judgment matrix to determine whether there are nodes that constitute a T-junction segment; Step S3: Based on the judgment in step S2, if there are no nodes that constitute a T-junction section, the status of the feeder section is directly determined using the fault location criteria. Step S4: Based on the judgment in step S2, if there are nodes that constitute a T-junction segment and the FTUs of the two child nodes upload the same information, the status of the T-junction segment is directly determined using the fault location criteria. Step S5: Based on the judgment in step S2, if there are nodes that constitute a T-junction segment and the FTU of the two child nodes upload different information, first correct the relevant diagonal elements of the fault judgment matrix, and then use the fault location criteria to determine the status of the T-junction segment. Step S6: Restore the corrected diagonal element values ​​in the fault judgment matrix; Step S7: Analyze the status of all feeder sections according to steps S2 to S6; In step S5, there are nodes constituting the T-junction section. The FTU information of the parent and child nodes of the feeder section is used for judgment. If the directions of the overcurrent information uploaded by the child node FTU are different, the relevant diagonal elements of the fault judgment matrix are first corrected. Using the idea of ​​equivalence, under the premise that the state of the T-junction section remains unchanged, the overcurrent direction information uploaded by the two child node FTUs is corrected to be the same, that is, the corresponding diagonal elements of the fault judgment matrix are corrected. The correction principle is: if the overcurrent direction information uploaded by the two child node FTUs is different, as long as one is "1", both are corrected to "1"; if there is no "1", as long as one is "−1", both are corrected to "−1". In step S5, there are nodes that constitute a T-junction segment. If the information uploaded by the child node FTU is different, after correction by the relevant diagonal elements of the fault judgment matrix, the state of the T-junction segment is determined by the fault location criterion. If the overcurrent direction information of the parent node and the child node is different, it indicates that the segment has a fault; if the information of the parent node and the child node is the same, it indicates that the segment has not a fault.

2. The active distribution network fault location method based on the correction matrix algorithm according to claim 1, characterized in that, In step S1, the FTU that uploads fault information is equipped with a device to detect the direction of the fault overcurrent. When a short-circuit fault occurs in a distribution network with distributed generation (DG), the directions of the fault overcurrent provided by the main power supply of the system and the downstream distributed generation (DG) at the fault point are opposite. In order to distinguish the above-mentioned fault overcurrent directions to adapt to the fault location of the distribution network under the condition of distributed generation (DG) access, it is stipulated that the direction from the main power supply on the system side to the end of the feeder or the distributed generation (DG) is the positive direction of the entire network. Each FTU in the distribution network with distributed generation (DG) is set with three working modes: "−1", "0", and "1" according to whether it detects the fault overcurrent and whether its direction is consistent with the positive direction of the entire network. If an FTU detects the fault overcurrent and its direction is consistent with the positive direction of the entire network, the FTU uploads information "1" to the control master station. If an FTU detects a fault overcurrent and its direction is opposite to the positive direction of the entire network, it uploads "−1"; if an FTU does not detect a fault overcurrent, it uploads "0".

3. The active distribution network fault location method based on the correction matrix algorithm according to claim 1, characterized in that, In step S1, a network description matrix D is formed based on the topological connection relationship of each node in the distribution network. The switches in the distribution network containing distributed generation DG include substation outgoing switches, sectionalizing switches and tie switches. According to graph theory, the entire 10kV distribution network is regarded as a tree structure, and the substation outgoing switches, sectionalizing switches and tie switches are regarded as nodes. The network description matrix D is a square matrix with a dimension equal to the total number of nodes in the distribution network. A node tree is constructed using all switches on the 10kV line, starting from the substation outgoing switch and numbered from smallest to largest along the main line. In a section, the node with the smallest number is the parent node, and the rest are child nodes. If node i and node j are the parent and child nodes of a feeder section, respectively, set the off-diagonal element d in matrix D. ij =1; otherwise, set it to 0; the network description matrix D is constructed according to the following rules: 。 4. The active distribution network fault location method based on the correction matrix algorithm according to claim 1, characterized in that, In step S1, a diagonal matrix—the fault information matrix G—of the same type as the network description matrix is ​​constructed based on the topological connection relationship of each node in the distribution network and the fault information uploaded by the FTUs. The diagonal elements are the information uploaded by each FTU in sequence. The construction rules of the fault information matrix are as follows: ； The fault judgment matrix P is obtained by adding the network description matrix D and the fault information matrix G. The off-diagonal elements of the fault diagnosis matrix P represent the topological connections between nodes in the distribution network. Its diagonal elements represent the fault overcurrent information detected by the FTU at each node.

5. The active distribution network fault location method based on the correction matrix algorithm according to claim 1, characterized in that, In step S2, the analysis starts from the first row of the fault judgment matrix. Based on the off-diagonal elements of the first row, it is determined whether there are nodes that constitute a T-junction segment. If the next level tree structure of the parent node device has multiple child node devices, then a T-junction area is formed.

6. The active distribution network fault location method based on the correction matrix algorithm according to claim 1, characterized in that, In step S3, if there are no nodes forming a T-junction section, the status of the feeder section is directly determined using the fault location criteria. If the overcurrent direction information uploaded by the parent and child FTU nodes of the feeder section is different, it indicates that the section has a fault; if the overcurrent direction information uploaded by the parent and child FTU nodes of the feeder section is the same, it indicates that the section has no fault.

7. The active distribution network fault location method based on the correction matrix algorithm according to claim 1, characterized in that, In step S4, there are nodes that constitute a T-connection section. The FTU information of the parent and child nodes of the feeder section is used to determine the status. If the direction of the overcurrent information uploaded by all child node FTUs is the same and the direction of the overcurrent information uploaded by the parent node FTU is different, the status of the feeder section is directly determined by the fault location criteria, indicating that a fault has occurred in the section. If the direction of the overcurrent information uploaded by all child node FTUs is the same as that of the overcurrent information uploaded by the parent node FTU, the status of the feeder section can be directly determined using the fault location criteria, indicating that no fault has occurred in that section.

8. The active distribution network fault location method based on the correction matrix algorithm according to claim 1, characterized in that, In step S7, it is determined whether all the elements in the N rows of the fault judgment matrix have been analyzed. If not, the analysis proceeds to step S2 to continue analyzing the next row. If the analysis is complete, all fault sections are output, and the fault location ends.

Images