System and method for processing single-phase-to-ground faults in distribution networks

Abstract

The application relates to the field of power distribution networks, in particular to a distribution network single-phase grounding fault processing system and method. The processing system comprises a data layer and a service layer. The data layer comprises an electrical quantity acquisition module and a power grid topology structure storage module, and provides the service layer with electrical quantity and power grid topology structure information. The service layer comprises a fault processing module, which is used for determining a fault line through fault line selection judgment after receiving a single-phase grounding fault signal, and generating a fault sketch for fault processing, the fault sketch being provided with a fault point pre-switch label, and the fault point pre-switch label being determined by the fault processing module according to zero sequence current. The data format is unified, the calculation cost is low, the limitation that data cannot be communicated and functions cannot be communicated between systems in the prior art is broken through, and the timeliness of fault processing is improved. The fault is positioned to a switch section level, and a sketch is used to enable a technician to accurately know the position where the fault occurs and how to minimize isolation of the fault.

Description

Technical Field

[0001] This application relates to the field of power distribution networks, and in particular to systems and methods for handling single-phase grounding faults in distribution networks. Background Technology

[0002] A single-phase grounding fault in a distribution network line will cause voltage imbalance across the entire bus, affecting the normal operation of the power system. Furthermore, the increased voltage in the non-faulty phases can cause the weak points in the insulation of the non-faulty phases to break down, thereby damaging the equipment. In particular, long-term operation under a single-phase grounding fault condition may develop into a phase-to-phase short circuit, expanding the scope of the accident.

[0003] To effectively manage single-phase grounding faults, timely monitoring and handling are essential. When handling a single-phase grounding fault, it's crucial to know its exact location. Currently, power distribution network technicians can only identify the grounded line using a low-current grounding fault location device after receiving a fault signal from the fault monitoring system. However, because distribution lines often extend over long distances and have complex branch structures, technicians must frequently test switches along the line and rely on experience to determine the fault's exact location. This approach is time-consuming and results in a poor electricity experience for residents in non-faulty areas. Summary of the Invention

[0004] This application provides a system and method for handling single-phase grounding faults in distribution networks.

[0005] Firstly, the distribution network single-phase grounding fault handling system provided in this application includes a data layer and a service layer;

[0006] The data layer includes an electrical quantity acquisition module and a power grid structure storage module. The electrical quantity acquisition module is used to provide electrical quantities to the service layer, and the power grid structure storage module is used to provide power grid topology information to the service layer.

[0007] The service layer includes a fault handling module, which, upon receiving a single-phase ground fault signal, performs fault line selection based on the electrical quantities to determine the faulty line and searches for the power grid topology information of the faulty line to generate a fault diagram for fault handling. The fault diagram connects the busbar and the outgoing switches associated with the busbar through connecting lines, and connects the outgoing switches with the line switches associated with the outgoing switches to represent the structure of the power grid. The fault diagram also includes a fault point preceding switch marker, which is determined by the fault handling module based on the electrical quantities.

[0008] Specifically, the electrical quantity includes the single-phase voltage of the station switch, and the service layer also includes a fault monitoring module, which is used to compare the single-phase voltage of the station switch with a set threshold range. When the single-phase voltage of the station switch does not belong to the threshold range, the fault monitoring module sends the single-phase grounding fault signal.

[0009] Specifically, the electrical quantities include outgoing phase current and outgoing reactive power. The fault handling module is equipped with a fault selection submodule, which is used to determine the faulty line by judging the faulty line based on the outgoing phase current and the outgoing reactive power.

[0010] Specifically, the fault selection submodule is equipped with a calculation program unit, which calculates the line fault probability according to a probability formula, and selects the line with the maximum line fault probability as the faulty line. The probability formula is:

[0011]

[0012] in, For the line i The aforementioned line fault probability, Indicates the line i The proportion of the change in outgoing phase current before and after the fault in the total change in outgoing phase current. Indicates the line i The proportion of the change in reactive power of outgoing lines before and after the fault in the total change in reactive power of outgoing lines. m and n For the set weight parameters, m ∈[0,1], n ∈[0,1], m + n =1.

[0013] Specifically, the power grid topology information includes bus-outgoing switch association, outgoing switch-line switch association, switch-switch terminal association, and terminal-terminal connection relationship;

[0014] The fault handling module includes a simplified diagram generation submodule, which queries the power grid topology to determine the busbars, line switches, and switch terminals associated with the faulty line, and draws the simplified fault diagram based on the busbars, line switches, and switch terminals.

[0015] Specifically, the simplified diagram generation submodule includes a busbar drawing program unit, which is used to find the busbar-outgoing switch association relationship to determine the busbar associated with the faulty line and draw the busbar associated with the faulty line in the fault simplified diagram;

[0016] The simplified diagram generation submodule also includes a switch drawing program unit, which is used to find the relationship between the outgoing switch and the line switch to determine the line switch associated with the faulty line and draw the line switch associated with the faulty line in the fault simplified diagram.

[0017] The simplified diagram generation submodule also includes a connection line drawing program unit, which is used to find the switch-terminal association relationship to determine the terminal associated with the outgoing switch of the faulty line and the terminal associated with the line switch, and draw the terminal associated with the outgoing switch of the faulty line and the terminal associated with the line switch in the fault simplified diagram, and draw the connection line according to the terminal-terminal connection relationship.

[0018] Specifically, the electrical quantity includes the zero-sequence current of the line switch, and the simplified diagram generation submodule is further provided with a zero-sequence current drawing program unit, which is used to draw the zero-sequence current of the line switch on the fault simplified diagram.

[0019] The simplified diagram generation submodule also includes a judgment program unit, which is used to identify the line switches with the maximum zero-sequence current and the switches marked as the preceding fault points in the simplified fault diagram, and to draw the preceding fault point switch marks in the simplified fault diagram.

[0020] Specifically, the fault handling module is further provided with a switch remote control submodule, which is used to control the opening and closing of the circuit switch in the fault diagram.

[0021] Secondly, the method for handling single-phase grounding faults in distribution networks provided in this application, when operated using the processing system described above, includes the following steps:

[0022] Acquire electrical quantities and power grid topology information;

[0023] Upon receiving a single-phase ground fault signal, the fault line is determined based on the electrical quantities.

[0024] The power grid topology information of the faulty line is searched to generate a fault diagram for fault handling. The fault diagram connects the bus and the outgoing switches associated with the bus through connecting lines, and connects the outgoing switches with the line switches associated with the outgoing switches to present the structure of the power grid. The fault diagram also has a fault point preceding switch mark, which is determined by the fault handling module based on the electrical quantities.

[0025] Specifically, the electrical quantities include single-phase voltage of the station switch, outgoing phase current, outgoing reactive power, and zero-sequence current of the line switch; the power grid topology information includes bus-outgoing switch association, outgoing switch-line switch association, switch-switch terminal association, and terminal-terminal connection relationship.

[0026] The method for sending the single-phase ground fault signal includes: comparing the single-phase voltage of the switch in the station with a set threshold range; when the single-phase switch voltage in the station does not belong to the threshold range, sending the single-phase ground fault signal.

[0027] The method for fault line selection includes: calculating the line fault probability according to a probability formula, and selecting the line with the maximum line fault probability as the faulty line. The probability formula is:

[0028]

[0029] in, For the line i The aforementioned line fault probability, Indicates the line i The proportion of the change in outgoing phase current before and after the fault in the total change in outgoing phase current. Indicates the line i The proportion of the change in reactive power of outgoing lines before and after the fault in the total change in reactive power of outgoing lines. m and n For the set weight parameters, m ∈[0,1], n ∈[0,1], m + n =1;

[0030] The method for finding the power grid topology information of the faulty line includes: finding the bus-outgoing switch association to determine the bus associated with the faulty line and drawing the bus associated with the faulty line in the fault diagram;

[0031] Locate the outgoing switch-line switch association to determine the line switch associated with the outgoing switch of the faulty line, and draw the line switch associated with the outgoing switch of the faulty line in the fault diagram.

[0032] Locate the switch-terminal relationships to determine the terminals associated with the outgoing switch of the faulty line and the terminals associated with the line switch, and draw the terminals associated with the outgoing switch of the faulty line and the terminals associated with the line switch in the fault diagram, and draw connecting lines according to the terminal-terminal connection relationships;

[0033] The method for determining the preceding switch marker of the fault point includes: plotting the zero-sequence current of the line switch on the fault diagram;

[0034] The circuit switch with the maximum zero-sequence current is marked as the preceding switch of the fault point, and the preceding switch is marked in the fault diagram.

[0035] This application has the following technical effects:

[0036] A program was designed to monitor and select fault lines and sections using single-phase voltage, phase current, reactive power, and zero-sequence current from substation switches for single-phase grounding faults in distribution networks. These electrical quantities can be directly obtained from the substation's distribution network system, eliminating the need for additional tools or systems. The data format is standardized, eliminating the need to train separate algorithms for each electrical quantity, resulting in low computational costs and overcoming the limitations of existing technologies where data and functionality are not interoperable between systems. This avoids the situation where technicians need to use multiple systems and tools combined with experience to locate faults during single-phase grounding faults, improving the timeliness of fault handling.

[0037] The fault can be directly located at the level of the switching section, and a simplified diagram focusing only on the faulty line can be redrawn, allowing technicians to more intuitively and clearly understand the location of the fault and how to minimize the isolation of the fault. Attached Figure Description

[0038] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts.

[0039] Figure 1 This is a framework diagram of the processing system in the embodiments of this application;

[0040] Figure 2 This is a schematic diagram of the fault selection submodule of the processing system in the embodiments of this application;

[0041] Figure 3 This is an example of a simplified fault diagram in an embodiment of this application. Detailed Implementation

[0042] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0043] Single-phase grounding faults have always been a thorny issue in power grid fault handling, because only by quickly locating the fault point can risks be reduced and frequent power outages in non-faulty areas caused by line testing be avoided. Currently, the distribution network in Wanzhi District has 13 substations, 11 of which are equipped with low-current grounding fault location devices. These devices come from different brands, and only some brands achieve the expected success rate. Installing high-success-rate low-current grounding fault location devices in all substations would incur a huge cost. Furthermore, the long construction period and high difficulty of installing these devices in high-load substations make comprehensive coverage impossible in a short time. More importantly, although technicians can identify the faulty line using the low-current grounding fault location device, they still need a significant amount of time to frequently test and disconnect power along the faulty line to determine the exact location of the fault. The longest power lines in the townships of Wanzhi District can reach 15km in length. Relying solely on low-current grounding fault location devices to identify the faulty line and then relying on experience to test and disconnect power is far from meeting the timeliness requirements for handling single-phase grounding faults. Furthermore, frequently disconnecting the power will result in a poor power experience for non-faulty areas.

[0044] Based on this, the inventors of this application analyzed grounding fault cases in Wanzhi District over the past year and proposed methods for fault monitoring using single-phase voltage of substation switches, fault line selection using phase current and reactive power, and fault segment selection using zero-sequence current. Furthermore, a single-phase grounding fault handling system suitable for the Wanzhi District distribution network system was designed. These electrical quantities can be directly obtained from the distribution automatic switch acquisition equipment in the substation's distribution network system, thus possessing excellent practicality and economy.

[0045] like Figure 1 As shown, the single-phase ground fault system of this distribution network includes a data layer and a service layer. The data layer includes an electrical quantity acquisition module and a power grid topology storage module. The electrical quantity acquisition module provides electrical quantities to the service layer, and the power grid topology storage module provides power grid topology information to the service layer. Currently, the substation distribution network switches in Wanzhi District are all digital switches integrating single-phase voltmeters, current sensors, transformer meters, and zero-sequence current sensors. They use a unified data format and communication method, and transmit the single-phase voltage, outgoing phase current, reactive power, and zero-sequence current of the line switches within the substation to the distribution network system in real time via a SCADA server, where they are stored in the electrical quantity acquisition module.

[0046] This embodiment includes a fault monitoring module in its service layer. This module retrieves the single-phase voltage values ​​of the substation switches from the electrical quantity acquisition module 50 times per second and performs threshold range judgment on these values. In the 10kV busbar distribution network system of a substation, the single-phase voltage of the substation switches refers to the voltage value of a specific phase (A, B, or C) of the busbar. Under normal operating conditions, the voltage of each phase should be its rated value. When a single-phase ground fault occurs, the phase voltage of the faulty phase will drop to near zero, while the phase voltages of the other two phases will increase. Therefore, the magnitude of the phase voltage can be used to determine whether a single-phase ground fault has occurred and which phase is faulty. Based on the statistical results of single-phase ground fault records from 13 substations in Wanzhi District over the past year, when the single-phase voltage of the substation switches is less than 2kV or greater than 8kV, it can be determined that a single-phase ground fault has occurred on the 10kV busbar. At this time, the fault monitoring module can initiate a single-phase ground fault signal with millisecond-level timeliness. The single-phase ground fault signal will notify the technicians to respond in the form of sound, light, and email, and automatically trigger the fault handling module to handle the fault.

[0047] The service layer of this embodiment also includes a fault handling module. Upon receiving a single-phase ground fault signal, it first calls the fault selection submodule to determine the fault location using the outgoing phase current and the outgoing reactive power. Figure 2 In the power grid structure shown, when a single-phase ground fault occurs, the ground capacitance current of the non-faulty lines flows to the grounding point. Therefore, the current of the faulty line is the sum of the ground capacitance currents of the entire network, flowing from the grounding point to the bus. For example, if a single-phase ground fault occurs in phase A of line II in the diagram, the current at the fault point is the sum of the currents of the non-faulty phase capacitances of the entire system, which is three times the current during normal operation. Therefore, a calculation program unit can be designed in the fault handling module to execute the probability formula calculation program to obtain the line fault probability, and the line with the maximum line fault probability can be identified as the faulty line. The probability formula is:

[0048]

[0049] in, For the line i The probability of line faults, Indicates the line i The proportion of the change in outgoing phase current before and after the fault in the total change in outgoing phase current. Indicates the line i The proportion of the change in reactive power of outgoing lines before and after the fault in the total change in reactive power of outgoing lines. m and n For the set weight parameters, m ∈[0,1], n ∈[0,1], m +n =1.

[0050] After obtaining the faulty line through the aforementioned system modules, a simplified diagram of the line needs to be drawn, and the location of the fault point needs to be marked on the diagram. This allows technicians to clearly and intuitively see the structure of the faulty line and the location of the fault, facilitating minimal isolation of the fault point. Since a complete power grid distribution diagram contains intricate lines and diverse electrical equipment, the power grid topology storage module in this embodiment builds tables according to the power grid topology hierarchy, storing bus-outgoing switch relationships, outgoing switch-line switch relationships, switch-switch terminal relationships, and terminal-terminal connection relationships. A simplified diagram generation submodule is also designed. When drawing a simplified diagram, it is only necessary to look up the data required for single-phase grounding fault handling from the table, connect the bus and its associated outgoing switches using connecting lines, and connect the outgoing switches and their associated line switches to present the power grid structure, thereby eliminating unnecessary information.

[0051] Specifically, in order to draw such Figure 3 The simplified diagram example shown in this embodiment includes a busbar drawing program unit, a switch drawing program unit, and a connecting line drawing program unit within the simplified diagram generation submodule. For example... Figure 3 As shown, a single-phase ground fault occurred at the Yingang substation. The fault location was determined to be on the Xianbao 111 line using the fault location submodule. The busbar drawing program unit searched for the busbar-outgoing switch associations associated with the Xianbao 111 outgoing switch and drew the busbar on the fault diagram, i.e., the 10kV busbar in the diagram. Then, the switch drawing program unit searched for the outgoing switch-line switch associations to find the line switches associated with the Xianbao 111 outgoing switch and drew these line switches on the fault diagram, i.e., "Center #2438", "Qiangwan #2330", "Luofan #2409", etc. Each switchgear has two terminals, and switches are connected to each other via these terminals. The connection line drawing program unit searched for switch-terminal associations and terminal-terminal connection relationships to determine how the terminals of these switches are connected, i.e., how the switches are connected to each other, and drew the connection lines on the fault diagram.

[0052] To facilitate real-time monitoring of the zero-sequence current of switches by technicians, the simplified diagram generation submodule in this embodiment includes a zero-sequence current drawing program unit to plot the zero-sequence current of line switches on the fault diagram. Simultaneously, a judgment program unit is designed to identify the line switches with the maximum zero-sequence current and mark them as the switches preceding the fault point, then mark these preceding switches on the fault diagram. The principle behind this design is that when a ground fault occurs in an ungrounded distribution network, the zero-sequence current of the non-faulty lines flows to the ground via the ground capacitance and then returns to the line through the busbar from the grounding point. The faulty line is divided into two parts by the grounding point, and its zero-sequence current flows in a loop composed of the ground capacitance, the ground, and the faulty line, but the directions of the zero-sequence current before and after the grounding are opposite. Therefore, it can be concluded that the zero-sequence current before the grounding point of the faulty line is the sum of the zero-sequence current of the preceding part of that line and the zero-sequence current of all non-faulty lines, with the largest amplitude across the entire network. This amplitude gradually decreases towards the busbar from the grounding point, eventually becoming the sum of the zero-sequence currents of the non-faulty lines. The zero-sequence current after the grounding point of the faulty line is the zero-sequence current of the subsequent part of the line. Considering that this part of the line is relatively short, its amplitude is close to 0. Therefore, we only need to find the line switch with the maximum value of zero-sequence current and mark it as the switch before the fault point in the fault diagram to know the location of the fault point. The location of the fault point is between the switch before the fault point and the adjacent line switch that is far away from the busbar.

[0053] After the technicians know the location of the fault, they can remotely control the opening and closing of the line switch through the switch remote control submodule of the processing system in this embodiment. By initiating the opening and closing signal to the line switch through wireless communication, remote control of the line switch within 100 kilometers can be achieved, thereby timely power disconnection and isolation of the fault point when a single-phase ground fault occurs.

[0054] Based on the above, when a single-phase ground fault occurs, the steps for handling it using the processing system of this embodiment are as follows:

[0055] S1: Obtain electrical quantities and power grid topology information;

[0056] S2: After receiving a single-phase ground fault signal, the fault line is determined by the electrical quantities.

[0057] S3: Locate the power grid topology information of the faulty line to generate a fault diagram for fault handling. The fault diagram connects the busbar and the outgoing switches associated with the busbar through connecting lines, and connects the outgoing switches with the line switches associated with the outgoing switches to present the structure of the power grid. The fault diagram also has a fault point preceding switch mark, which is determined by the fault handling module based on electrical quantities.

[0058] Specifically, the method for sending a single-phase ground fault signal includes: comparing the single-phase voltage of the switch in the station with a set threshold range; and sending a single-phase ground fault signal when the single-phase switch voltage in the station does not fall within the threshold range.

[0059] Specifically, the method for fault selection includes: calculating the line fault probability according to the probability formula, and taking the line with the maximum line fault probability as the faulty line.

[0060] Specifically, the method for finding the power grid topology information of the faulty line includes: finding the bus-outgoing switch relationship to determine the bus associated with the faulty line and drawing the bus associated with the faulty line on the fault diagram.

[0061] Specifically, the relationship between outgoing line switches and line switches is determined to identify the line switches associated with the outgoing line switch of the faulty line, and these line switches are then plotted on the fault diagram.

[0062] Specifically, the switch-terminal relationships are identified to determine the terminals associated with the outgoing switches and the circuit switches of the faulty line. These terminals are then drawn on the fault diagram, and connecting lines are drawn based on the terminal-terminal connection relationships.

[0063] Specifically, the method for determining the preceding switch markings at the fault point includes: drawing the zero-sequence current of the line switch on the fault diagram;

[0064] The circuit switch with the maximum zero-sequence current is marked as the preceding switch of the fault point, and the preceding switch is marked in the fault diagram.

[0065] Obviously, the embodiments described above are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0066] It should be understood that when the terms "first," "second," etc., are used in the claims, description, and drawings of this application, they are only used to distinguish different objects and not to describe a specific order. The terms "comprising" and "including" used in the description and claims of this application indicate the presence of the described features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof.

Claims

1. A system for handling single-phase grounding faults in a distribution network, characterized in that, Includes the data layer and the service layer; The data layer includes an electrical quantity acquisition module and a power grid structure storage module. The electrical quantity acquisition module is used to provide electrical quantities to the service layer, including zero-sequence current of line switches, outgoing phase current and outgoing reactive power. The power grid structure storage module is used to provide power grid topology information to the service layer. The service layer includes a fault handling module, which, upon receiving a single-phase ground fault signal, performs fault line selection based on the electrical quantities to determine the faulty line and searches for the power grid topology information of the faulty line to generate a fault diagram for fault handling. The fault diagram connects the busbar and the outgoing switches associated with the busbar through connecting lines, and connects the outgoing switches to the line switches associated with the outgoing switches to represent the structure of the power grid. The fault diagram also includes a fault point preceding switch mark, which is determined by the fault handling module based on the zero-sequence current of the line switches. The fault handling module includes a fault line selection submodule, which performs fault line selection based on the outgoing phase current and the outgoing reactive power to determine the faulty line.

2. The processing system according to claim 1, characterized in that, The electrical quantity includes the single-phase voltage of the switch in the station. The service layer also includes a fault monitoring module, which is used to compare the single-phase voltage of the switch in the station with a set threshold range. When the single-phase voltage of the switch in the station does not belong to the threshold range, the fault monitoring module sends the single-phase grounding fault signal.

3. The processing system according to claim 1, characterized in that, The fault selection submodule is equipped with a calculation program unit, which calculates the line fault probability according to a probability formula, and identifies the line with the maximum fault probability as the faulty line. The probability formula is: in, For the line i The aforementioned line fault probability, Indicates the line i The proportion of the change in outgoing phase current before and after the fault in the total change in outgoing phase current. Indicates the line i The proportion of the change in reactive power of outgoing lines before and after the fault in the total change in reactive power of outgoing lines. m and n For the set weight parameters, m ∈[0,1], n ∈[0,1], m + n =1.

4. The processing system according to claim 1, characterized in that, The power grid topology information includes bus-outgoing switch associations, outgoing switch-line switch associations, switch-switch terminal associations, and terminal-terminal connection relationships; The fault handling module includes a simplified diagram generation submodule, which queries the power grid topology to determine the busbars, line switches, and switch terminals associated with the faulty line, and draws the simplified fault diagram based on the busbars, line switches, and switch terminals.

5. The processing system according to claim 4, characterized in that, The simplified diagram generation submodule includes a busbar drawing program unit, which is used to find the busbar-outgoing switch association relationship to determine the busbar associated with the faulty line and draw the busbar associated with the faulty line in the fault simplified diagram. The simplified diagram generation submodule also includes a switch drawing program unit, which is used to find the relationship between the outgoing switch and the line switch to determine the line switch associated with the faulty line and draw the line switch associated with the faulty line in the fault simplified diagram. The simplified diagram generation submodule also includes a connection line drawing program unit, which is used to find the switch-terminal association relationship to determine the terminal associated with the outgoing switch of the faulty line and the terminal associated with the line switch, and draw the terminal associated with the outgoing switch of the faulty line and the terminal associated with the line switch in the fault simplified diagram, and draw the connection line according to the terminal-terminal connection relationship.

6. The processing system according to claim 4, characterized in that, The simplified diagram generation submodule is also equipped with a zero-sequence current drawing program unit, which is used to draw the zero-sequence current of the line switch on the fault simplified diagram. The simplified diagram generation submodule also includes a judgment program unit, which is used to identify the line switches with the maximum zero-sequence current and the switches marked as the preceding fault points in the simplified fault diagram, and to draw the preceding fault point switch marks in the simplified fault diagram.

7. The processing system according to claim 5, characterized in that, The fault handling module is also equipped with a switch remote control submodule, which is used to control the opening and closing of the circuit switch in the fault diagram.

8. A method for handling single-phase grounding faults in a distribution network, using the handling system described in claims 1-7, characterized in that, Includes the following steps: Acquire electrical quantities and power grid topology information; Upon receiving a single-phase ground fault signal, the fault line is determined based on the electrical quantities. The power grid topology information of the faulty line is searched to generate a fault diagram for fault handling. The fault diagram connects the bus and the outgoing switches associated with the bus through connecting lines, and connects the outgoing switches with the line switches associated with the outgoing switches to present the structure of the power grid. The fault diagram also has a fault point preceding switch mark, which is determined by the fault handling module based on the electrical quantities.

9. The processing method according to claim 8, characterized in that, The electrical quantities include single-phase voltage of the station switch, outgoing phase current, outgoing reactive power, and zero-sequence current of the line switch. The power grid topology information includes bus-outgoing switch association, outgoing switch-line switch association, switch-switch terminal association, and terminal-terminal connection relationship. The method for sending the single-phase ground fault signal includes: comparing the single-phase voltage of the switch in the station with a set threshold range; when the single-phase switch voltage in the station does not belong to the threshold range, sending the single-phase ground fault signal. The method for fault line selection includes: calculating the line fault probability according to a probability formula, and selecting the line with the maximum line fault probability as the faulty line. The probability formula is: in, For the line i The aforementioned line fault probability, Indicates the line i The proportion of the change in outgoing phase current before and after the fault in the total change in outgoing phase current. Indicates the line i The proportion of the change in reactive power of outgoing lines before and after the fault in the total change in reactive power of outgoing lines. m and n For the set weight parameters, m ∈[0,1], n ∈[0,1], m + n =1; The method for finding the power grid topology information of the faulty line includes: finding the bus-outgoing switch association to determine the bus associated with the faulty line and drawing the bus associated with the faulty line in the fault diagram; Locate the outgoing switch-line switch association to determine the line switch associated with the outgoing switch of the faulty line, and draw the line switch associated with the outgoing switch of the faulty line in the fault diagram. Locate the switch-terminal relationships to determine the terminals associated with the outgoing switch of the faulty line and the terminals associated with the line switch, and draw the terminals associated with the outgoing switch of the faulty line and the terminals associated with the line switch in the fault diagram, and draw connecting lines according to the terminal-terminal connection relationships; The method for determining the preceding switch marker of the fault point includes: plotting the zero-sequence current of the line switch on the fault diagram; The circuit switch with the maximum zero-sequence current is marked as the preceding switch of the fault point, and the preceding switch is marked in the fault diagram.

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