Method and system for preventing expansion of fault range caused by self-healing positioning error of distribution network

Abstract

The application provides a method and system for preventing the expansion of fault range caused by self-healing positioning error of distribution network, comprising: obtaining the connection relationship of distribution network line topology, and setting anti-continuous jump monitoring time; determining the power supply trunk path of distribution network; starting the self-healing transfer strategy when permanent fault occurs; continuously scanning the power supply line of permanent fault and the power supply line after starting the self-healing strategy within the preset anti-continuous jump monitoring time, judging whether the line after power recovery is stable, if yes, continuing the anti-continuous jump monitoring in the next cycle, if not, stopping the self-healing analysis of the power supply line of permanent fault and the power supply line after starting the self-healing strategy, until the anti-continuous jump monitoring time is reached, ending the self-healing program, simultaneously recovering the self-healing signal monitoring, and jumping to the normal self-healing isolation transfer logic. The application prevents the problem of expansion of fault range caused by self-healing positioning error by continuously monitoring the power supply trunk path after self-healing isolation transfer.

Description

Technical Field

[0001] This invention belongs to the field of distribution network self-healing technology, specifically relating to a method and system for preventing the expansion of the fault range due to distribution network self-healing positioning errors. Background Technology

[0002] Master station self-healing is a distribution network self-healing technology that, when a distribution network line fails, uses the cooperation between field automated switches and the automated master station to quickly isolate the fault on-site through protection, and dispatch the master station automation system to collect and monitor power grid anomalies and fault information, output power grid adjustment strategies, and finely isolate the faulty section of the distribution network line with little or no human intervention, and output the power supply to the non-faulty section.

[0003] In recent years, distribution self-healing technology has developed rapidly and has been widely applied in distribution network fault transfer and power restoration scenarios. Currently, most distribution self-healing technologies only focus on how to analyze the fault area and how to restore power to non-faulty areas. However, there is relatively little research on the problem that during the distribution self-healing transfer and power restoration process, due to reasons such as terminal signal failure and setting errors, the self-healing program may misjudge the fault range, leading to the fault being transferred to the backup line during the self-healing transfer process, causing the backup line to trip and amplifying the line fault. Summary of the Invention

[0004] In view of this, the present invention aims to solve the problem of expanding the scope of line faults due to fault location errors when the self-healing function is activated.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for preventing the expansion of the fault range due to distribution network self-healing location errors, comprising the following steps:

[0007] Obtain the topology connection relationship of the distribution network lines, and set the monitoring time to prevent consecutive tripping;

[0008] Determine the power supply trunk line path between two busbars in the distribution network;

[0009] When a permanent fault occurs in the power supply line of one busbar, the self-healing strategy is activated according to the established self-healing logic, and the non-faulty area is transferred to the power supply line of the other busbar according to the power supply trunk line path of the distribution network.

[0010] Within the preset anti-triple trip monitoring time, continuously scan the power supply lines that have experienced permanent faults and the lines that have been restored after the self-healing strategy has been activated, and determine whether the restored lines are stable. If so, continue anti-triple trip monitoring in the next cycle; otherwise, continue with the subsequent steps.

[0011] Stop the self-healing analysis of power supply lines that have experienced permanent faults and power lines that have been restored after the self-healing strategy has been activated, until the anti-triggering monitoring time is reached, then end the self-healing procedure, restore the self-healing signal monitoring, and switch to the normal self-healing isolation and power transfer logic.

[0012] Furthermore, the path of the power supply trunk line between the two busbars in the distribution network is determined, specifically including:

[0013] Starting from the 10kV busbar on one side, a breadth-first search is performed through the 10kV outgoing line switches on the substation side. During the search, access flags are set for the distribution network automation switches that are passed through, until the search ends at the 10kV busbar on the other side, thus forming the main power supply path of the distribution network.

[0014] Furthermore, before initiating the self-healing strategy according to the established self-healing logic, it also includes:

[0015] The protection trip start time of the distribution network automation interconnection switch is set to zero seconds, and the protection setting current is set according to the circuit parameters. The protection setting current includes at least overcurrent and zero-sequence setting current. The distribution network automation interconnection switch is a switch whose real-time status is in the position during the process of searching the power supply trunk line path of the distribution network.

[0016] Furthermore, continuously scan the power supply lines that have experienced permanent faults and the lines that have been restored after the self-healing strategy has been activated to determine whether the restored lines are stable. Specifically:

[0017] The system continuously scans each distribution network automation switch on the trunk path formed by the power supply line that has experienced a permanent fault and the line that has been restored after the self-healing strategy has been activated. It determines whether there are alarm signals and switch change signals sent to the automation master station. If a distribution network automation switch is detected to issue a fault protection action and a switch tripping signal, the restored line is considered unstable; otherwise, the restored line is considered stable.

[0018] Furthermore, the self-healing analysis for power supply lines that have experienced permanent faults and for lines restored after the self-healing strategy has been activated will be stopped until the anti-collapse monitoring time is reached, at which point the self-healing procedure will end. Specifically, this includes:

[0019] The self-healing program blocks the self-healing analysis on the trunk path formed by the power supply line with a permanent fault and the line restored after the self-healing strategy is activated. It discards all switch tripping signals and fault protection action signals in these two lines that are cached in the self-healing program until the anti-interruption monitoring time is reached. Then the self-healing program blocks the self-healing analysis on the trunk path and discards the signals.

[0020] Secondly, the present invention provides a system for preventing the expansion of the fault range due to distribution network self-healing location errors, comprising:

[0021] The self-healing transfer unit is used to obtain the topology connection relationship of the distribution network line and set the anti-interruption monitoring time; it is also used to determine the distribution network power supply trunk line path between two busbars in the distribution network line; it is also used to start the self-healing strategy according to the predetermined self-healing logic when a permanent fault occurs in the power supply line of one busbar, and transfer the non-faulty area to the power supply line of the other busbar according to the power supply trunk line path of the distribution network.

[0022] The anti-overlap monitoring unit is used to continuously scan the power supply lines that have experienced permanent faults and the lines that have been restored after the self-healing strategy has been activated within a preset anti-overlap monitoring time. It determines whether the restored lines are stable. If so, it continues to monitor against overlap in the next cycle. If not, it stops the self-healing analysis of the power supply lines that have experienced permanent faults and the lines that have been restored after the self-healing strategy has been activated until the anti-overlap monitoring time is reached. Then, it ends the self-healing program and jumps to the self-healing transfer unit to restore the self-healing signal monitoring and jump to the normal self-healing isolation transfer logic.

[0023] Furthermore, within the self-healing power transfer unit, the power supply trunk line path between the two busbars in the distribution network is determined, specifically including:

[0024] Starting from the 10kV busbar on one side, a breadth-first search is performed through the 10kV outgoing line switches on the substation side. During the search, access flags are set for the distribution network automation switches that are passed through, until the search ends at the 10kV busbar on the other side, thus forming the main power supply path of the distribution network.

[0025] Furthermore, in the self-healing transfer unit, before initiating the self-healing strategy according to the predetermined self-healing logic, it also includes:

[0026] The protection trip start time of the distribution network automation interconnection switch is set to zero seconds, and the protection setting current is set according to the circuit parameters. The protection setting current includes at least overcurrent and zero-sequence setting current. The distribution network automation interconnection switch is a switch whose real-time status is in the position during the process of searching the power supply trunk line path of the distribution network.

[0027] Furthermore, the anti-triggered circuit monitoring unit continuously scans power supply lines that have experienced permanent faults and lines that have been restored after the self-healing strategy has been activated, to determine whether the restored lines are stable. Specifically:

[0028] The system continuously scans each distribution network automation switch on the trunk path formed by the power supply line that has experienced a permanent fault and the line that has been restored after the self-healing strategy has been activated. It determines whether there are alarm signals and switch change signals sent to the automation master station. If a distribution network automation switch is detected to issue a fault protection action and a switch tripping signal, the restored line is considered unstable; otherwise, the restored line is considered stable.

[0029] Furthermore, in the anti-triple trip monitoring unit, the self-healing analysis of power supply lines that have experienced permanent faults and lines restored after the self-healing strategy has been activated is stopped until the anti-triple trip monitoring time is reached, at which point the self-healing procedure ends. Specifically, this includes:

[0030] The self-healing program blocks the self-healing analysis on the trunk path formed by the power supply line with a permanent fault and the line restored after the self-healing strategy is activated. It discards all switch tripping signals and fault protection action signals in these two lines that are cached in the self-healing program until the anti-interruption monitoring time is reached. Then the self-healing program blocks the self-healing analysis on the trunk path and discards the signals.

[0031] In summary, this invention provides a method and system for preventing the expansion of fault range due to distribution network self-healing location errors. The method includes acquiring the distribution network line topology and setting an anti-collapse monitoring time; determining the distribution network power supply trunk path; activating a self-healing transfer strategy when a permanent fault occurs; continuously scanning the power supply line with the permanent fault and the restored line after the self-healing strategy is activated within the preset anti-collapse monitoring time, determining whether the restored line is stable; if so, continuing anti-collapse monitoring in the next cycle; otherwise, continuing with subsequent steps; stopping self-healing analysis of the power supply line with the permanent fault and the restored line after the self-healing strategy is activated until the anti-collapse monitoring time is reached, ending the self-healing program, resuming self-healing signal monitoring, and switching to normal self-healing isolation transfer logic. This invention, by continuously monitoring the power supply trunk path after self-healing isolation transfer, avoids the problem of fault range expansion due to self-healing location errors in the restored line. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart illustrating a method for preventing the expansion of the fault range due to a self-healing location error in a distribution network, as provided in an embodiment of the present invention.

[0034] Figure 2 A schematic diagram illustrating the self-healing program for determining the fault range of the power supply trunk line in the distribution network, provided in an embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram of the self-healing procedure isolating the fault area according to an embodiment of the present invention;

[0036] Figure 4A schematic diagram illustrating the self-healing procedure for restoring power to a non-faulty area, provided in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram illustrating the isolation of a faulty area when the self-healing program provided in this embodiment of the invention mislocates the faulty area;

[0038] Figure 6 This is a schematic diagram illustrating the transfer of power when the self-healing program provided in this embodiment of the invention fails to locate the fault area.

[0039] Figure 7 This is a schematic diagram illustrating a real fault zone causing a line trip on the opposite side, provided in an embodiment of the present invention.

[0040] Figure 8 This is a schematic diagram illustrating how a real fault zone causes the opposite line to trip repeatedly during power supply cycles, as provided in an embodiment of the present invention.

[0041] Figure 9 This is a schematic diagram of the anti-interruption monitoring circuit provided in an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0043] Current power distribution self-healing functions generally rely on a combination of information, including electrical topology connections, terminal fault tripping information, and terminal protection / alarm signals, to determine the fault location range and identify non-faulty areas. The power distribution self-healing program then uses topology and load analysis to provide fault area isolation strategies and non-faulty area restoration strategies. Finally, the self-healing execution program sends instructions to the distribution network automation terminal for isolation and restoration.

[0044] by Figure 2 Taking the distribution network line shown as an example, the self-healing isolation and power transfer process under the condition of correct self-healing positioning is explained.

[0045] like Figure 2-4 As shown, the actual fault area is the section of line F01 between switches K2 and K3, and the self-healing program also determines that the fault range is this section of the line. At this time, the self-healing program begins to isolate the fault area, that is, to isolate the upstream and downstream switches and disconnect switches K2 and K3. Then, switch K4 is closed, and the non-faulty area is transferred to the opposite line F02.

[0046] However, if during the self-healing and power restoration process, due to reasons such as missed signal transmission from the terminal or incorrect setting, the self-healing program incorrectly determines the fault range, leading to the fault being transferred to the backup line during the self-healing power transfer process, causing the backup line to trip, the original fault range will expand, reducing power supply reliability. For example, under normal circumstances, fault protection signals should be sent from k1 and k2, and undervoltage signals should be sent from k3. If, due to incorrect setting of the differential protection switch k2 or protection failure, protection and switch trip signals are missed, the self-healing program will determine that the fault area is between k1 and k2 (see...). Figure 5 If this is the case, the subsequent transfer strategy will be combined with K4 (see...). Figure 6 The actual fault area is transferred to the opposite line, causing fault tripping of the opposite line K5, K4, or FD2 (see...). Figure 7 Furthermore, self-healing may close K6, resupplying the faulty area to FD3, causing K7, K8, or FD3 on the opposite side to trip (see...). Figure 8 In this situation, if the power grid has complex interconnections, it can easily cause a large-scale power grid trip, resulting in significant damage.

[0047] Based on this, the present invention provides a method and system for preventing the expansion of the fault range due to the self-healing positioning error of the distribution network, and prevents the fault area from being mistakenly transferred to the normal power supply line due to the protection device's failure to send signals or missetting, which would cause the opposite line to trip. If there are two or more connection points on the fault line, it will lead to the problem of multiple lines on the opposite side tripping due to faults.

[0048] The following is a detailed description of an embodiment of the method of the present invention for preventing the expansion of the fault range due to the self-healing positioning error of the distribution network.

[0049] Please see Figure 1 This embodiment provides a method to prevent the expansion of the fault range due to distribution network self-healing location errors, including the following steps:

[0050] S100: Obtain the topology connection relationship of the distribution network line and set the anti-interruption monitoring time.

[0051] It should be noted that the system obtains information on equipment such as power distribution lines, power distribution automation switches, disconnectors, power distribution transformers, and 10kV busbars, as well as the topological connection relationships between these devices, from the automation master station system; and sets the anti-interruption monitoring time t1, which is recommended to be 10 minutes.

[0052] S200: Determine the power supply trunk line path between two busbars in the distribution network.

[0053] It should be noted that the search begins from the 10kV busbar and proceeds through the 10kV outgoing switches on the substation side. During the search, access flags are set for the distribution network automation switches along the route until the search ends at the 10kV busbar on the other side, thus forming an effective distribution network power supply trunk path. Switches on the distribution network power supply trunk path with a real-time status of "out" are marked as "tie switches".

[0054] Set the protection trip start time of the distribution network automation "interconnection switch" to 0 seconds, and reasonably set the protection setting current, including at least overcurrent and zero-sequence setting current.

[0055] S300: When a permanent fault occurs in the power supply line of one bus, the self-healing strategy is activated according to the established self-healing logic, and the non-faulty area is transferred to the power supply line of the other bus according to the power supply trunk line path of the distribution network.

[0056] It should be noted that when a permanent fault occurs on line F01, and the self-healing strategy is activated according to the established self-healing logic, the faulty area is isolated and the power restoration switch is closed, the non-faulty area is then transferred to line F02 (e.g., Figure 3 Immediately activate the anti-casualty monitoring logic.

[0057] S400: Within the preset anti-triggered trip monitoring time, continuously scan the power supply lines that have experienced permanent faults and the lines that have been restored after the self-healing strategy has been activated, and determine whether the lines are stable after being restored. If so, continue anti-triggered trip monitoring in the next cycle; otherwise, continue with the subsequent steps.

[0058] It should be noted that within the preset anti-interruption monitoring time t1, the trunk path formed by the permanently faulted line F01 and the restored line F02 is continuously scanned (e.g., Figure 9 Each distribution network automation switch is monitored for alarm signals and switch position signals sent to the automation master station. When a fault protection action and switch tripping signal are detected from a distribution network automation switch, the process jumps to step S500 for processing. Otherwise, the process jumps to step S400 to continue periodic monitoring until the preset anti-interruption monitoring time t1 is reached, at which point the monitoring ends, normal self-healing signal monitoring is restored, and the process jumps to the normal self-healing isolation transfer logic.

[0059] S500: Stop the self-healing analysis of power supply lines that have experienced permanent faults and power lines that have been restored after the self-healing strategy has been activated, until the anti-triggering monitoring time is reached, then end the self-healing procedure, restore the self-healing signal monitoring, and switch to the normal self-healing isolation and power transfer logic.

[0060] It should be noted that the self-healing blockade procedure performs self-healing analysis on the F01 and F02 trunk lines and discards all switch tripping signals and fault protection action signals cached in the self-healing procedure for these two lines until the preset anti-interruption monitoring time t1 is reached. At this point, the self-healing procedure ends the self-healing analysis blockade on the F01 and F02 trunk lines, ends the discarding of all switch tripping signals and fault protection action signals for these two lines, restores normal self-healing signal monitoring, and jumps to normal self-healing isolation and transfer logic.

[0061] This embodiment provides a method to prevent the expansion of the fault range due to distribution network self-healing location errors. The method includes: acquiring the distribution network line topology and connection relationship, and setting an anti-collision monitoring time; determining the power supply trunk path of the distribution network; activating a self-healing power transfer strategy when a permanent fault occurs; continuously scanning the power supply line with the permanent fault and the restored line after the self-healing strategy is activated within the preset anti-collision monitoring time, determining whether the restored line is stable; if so, continuing anti-collision monitoring in the next cycle; otherwise, continuing with subsequent steps; stopping the self-healing analysis of the power supply line with the permanent fault and the restored line after the self-healing strategy is activated until the anti-collision monitoring time is reached, ending the self-healing program, restoring self-healing signal monitoring, and switching to normal self-healing isolation power transfer logic.

[0062] Compared to the previous mesh-type power transfer lines, which suffered from fault location errors due to missed signals or incorrect settings by protection devices, leading to widespread power outages, this new system can prevent the fault range from expanding through anti-triggered monitoring. Furthermore, by properly setting the protection settings at interconnection points, permanent faults can be isolated to a minimum, preventing the fault from spreading to the opposite line and maximizing the power supply reliability of the distribution lines.

[0063] The above is a detailed description of an embodiment of a method for preventing the expansion of the fault range due to distribution network self-healing location errors according to the present invention. The following will provide a detailed description of an embodiment of a system for preventing the expansion of the fault range due to distribution network self-healing location errors according to the present invention.

[0064] This embodiment provides a system to prevent the expansion of the fault range due to the self-healing location error of the distribution network, including: a self-healing power transfer unit and an anti-interruption monitoring unit.

[0065] In this embodiment, the self-healing transfer unit is used to obtain the topological connection relationship of the distribution network line and set the anti-interruption monitoring time; it is also used to determine the distribution network power supply trunk line path between two busbars in the distribution network line; and it is also used to start the self-healing strategy according to the predetermined self-healing logic when a permanent fault occurs in the power supply line of one busbar, and transfer the non-faulty area to the power supply line of the other busbar according to the power supply trunk line path of the distribution network.

[0066] Specifically, determining the power supply trunk line path between two busbars in the distribution network includes:

[0067] Starting from the 10kV busbar on one side, a breadth-first search is performed through the 10kV outgoing line switches on the substation side. During the search, access flags are set for the distribution network automation switches that are passed through, until the search ends at the 10kV busbar on the other side, thus forming the main power supply path of the distribution network.

[0068] Before initiating the self-healing strategy according to the established self-healing logic, the following steps are also included:

[0069] The protection trip start time of the distribution network automation interconnection switch is set to zero seconds, and the protection setting current is set according to the circuit parameters. The protection setting current includes at least overcurrent and zero-sequence setting current. The distribution network automation interconnection switch is a switch whose real-time status is in the position during the process of searching the power supply trunk line path of the distribution network.

[0070] In this embodiment, the anti-triggered trip monitoring unit is used to continuously scan the power supply line that has a permanent fault and the power line that has been restored after the self-healing strategy is activated within a preset anti-triggered trip monitoring time, and determine whether the power line after restoration is stable. If so, the anti-triggered trip monitoring continues in the next cycle. If not, the self-healing analysis of the power supply line that has a permanent fault and the power line that has been restored after the self-healing strategy is activated is stopped until the anti-triggered trip monitoring time is reached and the self-healing program ends. At the same time, it jumps to the self-healing transfer unit, restores the self-healing signal monitoring, and jumps to the normal self-healing isolation transfer logic.

[0071] Specifically, the system continuously scans power supply lines that have experienced permanent faults and lines that have been restored after the self-healing strategy has been activated to determine whether the restored lines are stable.

[0072] The system continuously scans each distribution network automation switch on the trunk path formed by the power supply line that has experienced a permanent fault and the line that has been restored after the self-healing strategy has been activated. It determines whether there are alarm signals and switch change signals sent to the automation master station. If a distribution network automation switch is detected to issue a fault protection action and a switch tripping signal, the restored line is considered unstable; otherwise, the restored line is considered stable.

[0073] Stop self-healing analysis for power supply lines that have experienced permanent faults and for lines restored after the self-healing strategy has been activated, until the anti-collapse monitoring time is reached and the self-healing procedure ends. Specifically, this includes:

[0074] The self-healing program blocks the self-healing analysis on the trunk path formed by the power supply line with a permanent fault and the line restored after the self-healing strategy is activated. It discards all switch tripping signals and fault protection action signals in these two lines that are cached in the self-healing program until the anti-interruption monitoring time is reached. Then the self-healing program blocks the self-healing analysis on the trunk path and discards the signals.

[0075] It should be noted that the system provided in this embodiment for preventing the expansion of the fault range due to the self-healing location error of the distribution network is used to implement the method for preventing the expansion of the fault range due to the self-healing location error of the distribution network provided in the aforementioned embodiment. The specific design of each unit is based on the complete implementation of this method, and will not be described in detail here.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preventing the expansion of the fault range due to distribution network self-healing location errors, characterized in that, Includes the following steps: Obtain the topology connection relationship of the distribution network lines, and set the monitoring time to prevent consecutive tripping; Determine the power supply trunk line path between two busbars in the distribution network; When a permanent fault occurs in the power supply line of one busbar, the self-healing strategy is activated according to the predetermined self-healing logic, and the non-faulty area is transferred to the power supply line of the other busbar according to the power supply trunk line path of the distribution network. Within the preset anti-triple trip monitoring time, continuously scan the power supply line that has experienced a permanent fault and the power-restored line after the self-healing strategy is activated, and determine whether the power-restored line is stable. If so, continue anti-triple trip monitoring in the next cycle; otherwise, continue with the subsequent steps. Stop the self-healing analysis of the power supply line that has suffered a permanent fault and the power line that has been restored after the self-healing strategy is activated, until the anti-triggering monitoring time is reached, then end the self-healing program, restore the self-healing signal monitoring, and switch to the normal self-healing isolation power transfer logic.

2. The method for preventing the expansion of the fault range due to self-healing location errors in the distribution network according to claim 1, characterized in that, Determine the power supply trunk line path between two busbars in the distribution network, specifically including: Starting from the 10kV busbar on one side, a breadth-first search is performed through the 10kV outgoing line switches on the substation side. During the search, access flags are set for the distribution network automation switches that are passed through, until the search ends at the 10kV busbar on the other side, thus forming the main power supply path of the distribution network.

3. The method for preventing the expansion of the fault range due to distribution network self-healing location errors according to claim 2, characterized in that, Before initiating the self-healing strategy according to the established self-healing logic, the following steps are also included: The protection tripping start time of the distribution network automation interconnection switch is set to zero seconds, and the protection setting current is set according to the circuit parameters. The protection setting current includes at least overcurrent and zero-sequence setting current. The distribution network automation interconnection switch is a switch whose real-time status is in the position during the process of searching the power supply trunk line path of the distribution network.

4. The method for preventing the expansion of the fault range due to self-healing location errors in the distribution network according to claim 1, characterized in that, The system continuously scans the power supply lines that have experienced permanent faults and the lines that have been restored after the self-healing strategy has been activated to determine whether the restored lines are stable. Specifically: The system continuously scans each distribution network automation switch on the trunk path formed by the power supply line that has experienced a permanent fault and the line that has been restored after the self-healing strategy is activated. It determines whether there are alarm signals and switch position signals sent to the automation master station. If a distribution network automation switch is detected to issue a fault protection action and a switch opening signal, the line after restoration is considered unstable; otherwise, the line after restoration is considered stable.

5. The method for preventing the expansion of the fault range due to self-healing location errors in the distribution network according to claim 1, characterized in that, Stop the self-healing analysis of the power supply line that has experienced a permanent fault and the restored power line after the self-healing strategy has been activated, and terminate the self-healing procedure after the anti-collapse monitoring time is reached. Specifically, this includes: The self-healing program blocks the self-healing analysis on the trunk path formed by the power supply line that has a permanent fault and the line that has been restored after the self-healing strategy is activated. It also discards all switch tripping signals and fault protection action signals in these two lines that are cached in the self-healing program until the anti-interruption monitoring time is reached. Then the self-healing program blocks the self-healing analysis on the trunk path and discards the signals.

6. A system for preventing the expansion of the fault range due to distribution network self-healing location errors, characterized in that, include: The self-healing power supply unit is used to obtain the topology connection relationship of the distribution network line and set the anti-interruption monitoring time. It is also used to determine the power supply trunk line path between two busbars in the distribution network; it is also used to activate the self-healing strategy according to the predetermined self-healing logic when a permanent fault occurs in the power supply line of one busbar, and transfer the non-faulty area to the power supply line of the other busbar according to the power supply trunk line path of the distribution network. The anti-overlap monitoring unit is used to continuously scan the power supply line that has experienced a permanent fault and the power line that has been restored after the self-healing strategy has been activated within the preset anti-overlap monitoring time. It determines whether the power line is stable after restoration. If it is, the anti-overlap monitoring continues in the next cycle. If not, the self-healing analysis of the power supply line that has experienced a permanent fault and the power line that has been restored after the self-healing strategy has been activated is stopped until the anti-overlap monitoring time is reached. Then the self-healing program ends, and the system jumps to the self-healing transfer unit to restore the self-healing signal monitoring and jumps to the normal self-healing isolation transfer logic.

7. The system for preventing the expansion of the fault range due to self-healing location errors in the distribution network according to claim 6, characterized in that, In the self-healing power supply unit, the power supply trunk line path between two busbars in the distribution network is determined, specifically including: Starting from the 10kV busbar on one side, a breadth-first search is performed through the 10kV outgoing line switches on the substation side. During the search, access flags are set for the distribution network automation switches that are passed through, until the search ends at the 10kV busbar on the other side, thus forming the main power supply path of the distribution network.

8. The system for preventing the expansion of the fault range due to self-healing location errors in the distribution network according to claim 7, characterized in that, In the self-healing transfer unit, before activating the self-healing strategy according to the predetermined self-healing logic, it further includes: The protection tripping start time of the distribution network automation interconnection switch is set to zero seconds, and the protection setting current is set according to the circuit parameters. The protection setting current includes at least overcurrent and zero-sequence setting current. The distribution network automation interconnection switch is a switch whose real-time status is in the position during the process of searching the power supply trunk line path of the distribution network.

9. The system for preventing the expansion of the fault range due to self-healing location errors in the distribution network according to claim 6, characterized in that, The anti-trigger monitoring unit continuously scans the power supply lines that have experienced permanent faults and the lines that have been restored after the self-healing strategy has been activated, and determines whether the restored lines are stable. Specifically: The system continuously scans each distribution network automation switch on the trunk path formed by the power supply line that has experienced a permanent fault and the line that has been restored after the self-healing strategy is activated. It determines whether there are alarm signals and switch position signals sent to the automation master station. If a distribution network automation switch is detected to issue a fault protection action and a switch opening signal, the line after restoration is considered unstable; otherwise, the line after restoration is considered stable.

10. The system for preventing the expansion of the fault range due to self-healing location errors in the distribution network according to claim 6, characterized in that, In the anti-triple trip monitoring unit, the self-healing analysis of the power supply line that has experienced a permanent fault and the restored power line after the self-healing strategy has been activated is stopped until the anti-triple trip monitoring time is reached, at which point the self-healing program ends. Specifically, this includes: The self-healing program blocks the self-healing analysis on the trunk path formed by the power supply line that has a permanent fault and the line that has been restored after the self-healing strategy is activated. It also discards all switch tripping signals and fault protection action signals in these two lines that are cached in the self-healing program until the anti-interruption monitoring time is reached. Then the self-healing program blocks the self-healing analysis on the trunk path and discards the signals.

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