Distribution network single-phase earth fault processing system and method

Abstract

The invention relates to the field of power distribution networks, in particular to a distribution network single-phase earth 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 topological structure storage module, and provides electrical quantity and power grid topological structure information for the service layer. The service layer comprises a fault processing module and is used for carrying out fault line selection judgment to determine a fault line after receiving the single-phase earth fault signal and generating a fault sketch used for fault processing, the fault sketch is provided with a fault point preorder switch mark, and the fault point preorder switch mark is determined by the fault processing module according to the zero sequence current. The data format is uniform, the calculation cost is low, the limitation that data and functions between systems are not intercommunicated in the prior art is broken through, and the timeliness of fault processing is improved. A fault is positioned to a switch section level, and a technician accurately knows the position of the fault and how to carry out minimum isolation on the fault through a sketch.

Description

Technical Field

[0001] The present application relates to the field of power distribution networks, and in particular to a distribution network single-phase grounding fault processing system and method. Background Art

[0002] A single-phase grounding fault in the distribution network line will cause an imbalance in the voltage of the entire busbar, affecting the normal operation of the power system. In addition, due to the increase in the voltage of the non-fault phase, the weak insulation link of the non-fault phase may be broken down, thereby damaging the equipment. In particular, long-term operation and a single-phase grounding fault state may develop into a phase-to-phase short circuit, expanding the scope of the accident.

[0003] In order to effectively control single-phase grounding faults, it is necessary to monitor and handle the faults in a timely manner. When handling single-phase grounding faults, it is necessary to know the specific location of the single-phase grounding fault. At present, technicians in the field of power distribution networks can only select the grounded line through a small current grounding line selection device after receiving the fault signal through the fault monitoring system. Then, because the distribution lines often extend for a long distance and have complex branch structures, technicians can only frequently try to pull the switch on the line and combine experience to determine the specific location of the fault point on the line. The processing timeliness is low, and it will bring a very poor electricity experience to residents in non-fault areas. Summary of the invention

[0004] The present application provides a distribution network single-phase grounding fault processing system and method.

[0005] In a first aspect, the distribution network single-phase grounding fault processing system provided by the present application includes a data layer and a service layer; The data layer includes an electrical quantity acquisition module and a power grid structure storage module, wherein 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; The service layer includes a fault processing module, which is used to perform fault line selection judgment according to the electrical quantity after receiving a single-phase grounding fault signal to determine the fault line, and to find the power grid topology information of the fault line to generate a fault diagram for fault processing. The fault diagram connects the busbar and the outgoing switch associated with the busbar through a connecting line, and connects the outgoing switch with the line switch associated with the outgoing switch to present the structure of the power grid. The fault diagram also has a fault point preceding switch mark, and the fault point preceding switch mark is determined by the fault processing module according to the electrical quantity.

[0006] Specifically, the electrical quantity includes the single-phase voltage of the station switch, and the service layer also includes a fault monitoring module for comparing the single-phase voltage of the station switch with a set threshold interval. When the single-phase switch voltage in the station does not belong to the threshold interval, the fault monitoring module sends the single-phase grounding fault signal.

[0007] Specifically, the electrical quantity includes outgoing line phase current and outgoing line reactive power, and the fault processing module is provided with a fault line selection submodule for performing fault line selection judgment according to the outgoing line phase current and the outgoing line reactive power to determine the faulty line.

[0008] Specifically, the fault line selection submodule is provided with a calculation program unit for calculating the line fault probability according to a probability formula, and taking the line with the maximum line fault probability as the fault line, and the probability formula is: in, For Line i The line failure probability, Indicates line i The proportion of the outgoing phase current change before and after the fault in all outgoing phase current changes, Indicates line i The proportion of the reactive power change of the outgoing line before and after the fault in all the reactive power changes of the outgoing line, m and n is the weight parameter set, m ∈[0,1], n ∈[0,1], m + n =1.

[0009] Specifically, the power grid topology information includes a busbar-outgoing switch association relationship, an outgoing switch-line switch association relationship, a switch-switch terminal association relationship, and a terminal-terminal connection relationship; The fault processing module is provided with a schematic diagram generating submodule for querying the power grid topology to determine the bus, line switch and switch terminal associated with the fault line, and drawing the fault schematic diagram according to the bus, line switch and switch terminal.

[0010] Specifically, the schematic diagram generating submodule is provided with a busbar drawing program unit, which is used to search the busbar-outgoing switch association relationship to determine the busbar associated with the fault line and draw the busbar associated with the fault line in the fault schematic diagram; The schematic diagram generating submodule is also provided with a switch drawing program unit, which is used to search the outgoing line switch-line switch association relationship to determine the line switch associated with the fault line and draw the line switch associated with the fault line in the fault schematic diagram; The schematic diagram generating submodule is also provided with a connection line drawing program unit, which is used to search the switch-terminal association relationship to determine the terminal associated with the outgoing switch of the fault line and the terminal associated with the line switch, and draw the terminal associated with the outgoing switch of the fault line and the terminal associated with the line switch in the fault schematic diagram, and draw the connection lines according to the terminal-terminal connection relationship.

[0011] Specifically, the electrical quantity includes a zero-sequence current of a line switch, and the schematic diagram generating submodule is further provided with a zero-sequence current drawing program unit for drawing the zero-sequence current of the line switch in the fault schematic diagram; The schematic diagram generating submodule is also provided with a judgment program unit for marking the line switch with the maximum zero-sequence current of the line switch as a preceding switch of the fault point, and drawing the preceding switch mark of the fault point in the fault schematic diagram.

[0012] Specifically, the fault processing module is further provided with a switch remote control submodule for controlling the opening and closing of the line switches in the fault diagram.

[0013] In a second aspect, the method for processing a single-phase grounding fault in a distribution network provided by the present application is operated using the processing system as described above, and includes the following steps: Obtain information on electrical quantities and grid topology; After receiving the single-phase ground fault signal, a fault line selection judgment is performed according to the electrical quantity to determine the fault line; The grid topology information of the fault line is searched to generate a fault diagram for fault processing. The fault diagram connects the busbar and the outgoing switch associated with the busbar through a connecting line, and connects the outgoing switch with the line switch associated with the outgoing switch to present the structure of the grid. The fault diagram also has a preceding switch mark of the fault point, and the preceding switch mark of the fault point is determined by the fault processing module according to the electrical quantity.

[0014] Specifically, the electrical quantities include the single-phase voltage of the station switch, the phase current of the outgoing line, the reactive power of the outgoing line and the zero-sequence current of the line switch, and the grid topology information includes the busbar-outgoing line switch association relationship, the outgoing line switch-line switch association relationship, the switch-switch terminal association relationship and the terminal-terminal connection relationship; The method for sending the single-phase ground fault signal comprises: comparing the single-phase voltage of the switch in the station with a set threshold interval, and sending the single-phase ground fault signal when the single-phase switch voltage in the station does not belong to the threshold interval; The method for fault line selection comprises: calculating the line fault probability according to a probability formula, and taking the line with the maximum line fault probability as the fault line, wherein the probability formula is: in, For Line i The line failure probability, Indicates line i The proportion of the outgoing phase current change before and after the fault in all outgoing phase current changes, Indicates line i The proportion of the reactive power change of the outgoing line before and after the fault in all the reactive power changes of the outgoing line, m and n is the weight parameter set, m ∈[0,1], n ∈[0,1], m + n =1; The method for searching for the grid topology information of the fault line comprises: searching for the bus-outgoing switch association relationship to determine the bus associated with the fault line and drawing the bus associated with the fault line in the fault diagram; Searching for the outgoing switch-line switch association relationship to determine the line switch associated with the outgoing switch of the faulty line and drawing the line switch associated with the outgoing switch of the faulty line in the fault diagram; Searching the switch-terminal association relationship to determine the terminal associated with the outgoing switch of the fault line and the terminal associated with the line switch, and drawing the terminal associated with the outgoing switch of the fault line and the terminal associated with the line switch in the fault diagram, and drawing connecting lines according to the terminal-terminal connection relationship; The method for determining the preceding switch mark of the fault point comprises: drawing the zero-sequence current of the line switch in the fault diagram; The line switch whose zero-sequence current is the maximum is marked as the preceding switch of the fault point, and the mark of the preceding switch of the fault point is drawn in the fault diagram.

[0015] This application has the following technical effects: For single-phase grounding faults in the distribution network, a program is designed to use the single-phase voltage, phase current, reactive power, and zero-sequence current of the station switch for fault monitoring and fault line selection. These electrical quantities can be directly obtained from the distribution network system of the substation, so there is no need to use additional tools or systems. The data format is unified, and there is no need to train a separate algorithm for each electrical quantity. The calculation cost is low, breaking through the limitations of the existing technology that the data and functions between systems are not interoperable. It avoids the situation where technicians need to use multiple systems and tools and combine experience to locate the fault when a single-phase grounding fault occurs, thereby improving the timeliness of fault handling.

[0016] The fault can be directly located at the switch section level, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present application will become easily understood. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-restrictive manner, and the same or corresponding numbers represent the same or corresponding parts.

[0018] Figure 1 is a framework diagram of a processing system in an embodiment of the present application; Figure 2 is a schematic diagram of a fault line selection submodule of a processing system in an embodiment of the present application; Figure 3 It is an example of a fault diagram in an embodiment of the present application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0020] Single-phase grounding fault has always been a thorny problem in power grid fault handling, because only by quickly locating the fault point can the risk of hidden dangers be reduced and frequent power outages in non-fault areas caused by test lines be avoided. At present, there are 13 substations in the distribution network of Wanzhi District, 11 of which are equipped with small current grounding line selection devices. These small current grounding line selection devices are of different brands, and only some brands can achieve the expected line selection success rate. If all substations are to be installed with small current grounding devices with a high line selection success rate, it will bring a huge cost investment. In addition, due to the long construction period and high construction difficulty of installing small current grounding line selection devices in large-load substations, it is impossible to complete full coverage in a short time. More importantly, although technicians can determine the fault line through the small current grounding line selection device, they still need a lot of time to frequently test the power outage on the fault line to determine the specific location of the fault point. The longest line in each township of Wanzhi District can reach 15km in length. It is far from meeting the timeliness requirements of single-phase grounding fault handling to determine the fault line only by using the small current grounding line selection device and then relying on experience to test the specific location of the fault point. Moreover, frequent power outage tests will also bring a poor power consumption experience to non-fault areas.

[0021] Based on this, the inventor of this application analyzed the grounding fault cases in Wanzhi District in the past year, proposed a method of fault monitoring through the single-phase voltage of the station switch, fault line selection through phase current and reactive power, and fault section selection through zero-sequence current, and designed a distribution network single-phase grounding fault processing system suitable for the distribution network system in Wanzhi District. These electrical quantities can be directly obtained by the distribution switch acquisition equipment in the distribution network system of the substation, so they have excellent practicality and economy.

[0022] like Figure 1 As shown, the distribution network single-phase grounding fault system includes a data layer and a service layer, wherein the data layer includes an electrical quantity acquisition module and a power grid topology 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. At present, the substation distribution network switches in Wanzhi District are all digital switches integrated with single-phase voltmeters, current sensors, transformer meters, and zero-sequence current sensors. They use a unified data format and communication method, and send the single-phase voltage of the station switch, the outgoing line phase current, the reactive power, and the zero-sequence current of the line switch in real time to the distribution network system through the scada server and store them in the electrical quantity acquisition module.

[0023] A fault monitoring module is designed in the service layer of this embodiment. The fault monitoring module takes the value of the single-phase voltage of the station switch from the electrical quantity acquisition module at a frequency of 50 times per second, and performs a threshold interval judgment on this value. In the distribution system of the 10kV busbar of the substation, the single-phase voltage of the station switch refers to the voltage value of a certain phase (phase A, phase B or phase C) of the busbar. Under normal operation, the voltage of each phase should be the rated value. When a single-phase grounding fault occurs, the phase voltage of the faulty phase will drop to close to 0, and 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 grounding fault has occurred and the faulty phase. According to the statistical results of single-phase fault grounding records of 13 substations in Wanzhi District in the past year, when the single-phase voltage of the station switch is less than 2kV or greater than 8kV, it can be determined that a single-phase grounding fault has occurred on the 10kV busbar. At this time, the fault monitoring module can initiate a single-phase grounding fault signal with a timeliness of milliseconds. The single-phase grounding fault signal will notify the technician to respond in the form of sound, light, or email, and automatically trigger the fault handling module to handle the fault.

[0024] The service layer of this embodiment also designs a fault processing module. When receiving a single-phase ground fault signal, it will first call the fault line selection submodule to use the outgoing line phase current and outgoing line reactive power to perform fault line selection judgment. Figure 2 In the grid structure shown, when a single-phase grounding fault occurs, the capacitive current of the non-fault line will flow to the grounding point. Therefore, the current of the fault line is the sum of the capacitive current of the entire network, flowing from the grounding point to the bus. For example, a single-phase grounding fault occurs in phase A of line II in the figure. At this time, the current at the fault point is the sum of the current of the non-fault phase capacitance of the entire system, which is three times the normal operation. Therefore, the calculation program unit can be designed in the fault processing module, and the calculation program of the probability formula can be executed to obtain the line fault probability, and the line with the maximum line fault probability is taken as the fault line. The probability formula is: in, For Line i The line failure probability, Indicates line i The proportion of the outgoing phase current change before and after the fault in all outgoing phase current changes, Indicates line i The proportion of the reactive power change of the outgoing line before and after the fault in all the reactive power changes of the outgoing line, m and n is the weight parameter set, m ∈[0,1], n ∈[0,1], m + n =1.

[0025] After obtaining the fault line through the above-mentioned system module, it is necessary to draw a simple diagram of the line and mark the location of the fault point on the simple diagram, so that the technicians can clearly and intuitively see the structure of the fault line and the location of the fault, so as to facilitate them to minimize the isolation of the fault point. Since the complete distribution diagram of the power grid contains intricate lines and diversified electrical equipment, the power grid topology storage module of this embodiment builds a table according to the topological structure level of the power grid, and stores the bus-outgoing switch association relationship, the outgoing switch-line switch association relationship, the switch-switch terminal association relationship and the terminal-terminal connection relationship respectively. A simple diagram generation submodule is also designed. When drawing a simple diagram, it is only necessary to find the data required for single-phase grounding fault processing from the table, connect the bus and the outgoing switch associated with the bus through a connecting line, and connect the outgoing switch with the line switch associated with the outgoing switch to present the structure of the power grid, thereby eliminating the remaining unnecessary information.

[0026] Specifically, in order to draw Figure 3 In the example of the simplified diagram shown, the simplified diagram generation submodule of this embodiment is designed with a busbar drawing program unit, a switch drawing program unit and a connection line drawing program unit. Figure 3 As shown, a single-phase grounding fault occurred in Yingang substation. The fault line selection submodule determined that the fault location occurred in Xianbao 111 line. The busbar drawing program unit searched for the busbar-outgoing switch association relationship and the busbar associated with the Xianbao 111 outgoing switch, and drew the busbar in the fault diagram, that is, the 10kV busbar in the figure. Then the switch drawing program unit searched for the outgoing switch-line switch association relationship to find the line switch associated with the Xianbao 111 outgoing switch, and drew these line switches in the fault diagram, that is, "Center #2438", "Qiangwan #2330", "Luofan #2409" and so on in the figure. Each switch device has two terminals, and switches are connected through terminals. The connecting line drawing program unit searches for the switch-terminal association relationship and the terminal-terminal connection relationship, and then knows how the terminals of these switches are connected, that is, how the switches are connected, and draws the connecting lines in the fault diagram.

[0027] In order to facilitate the technicians to view the zero-sequence current of the switch in real time, a zero-sequence current drawing program unit is also designed in the schematic generation submodule of the present embodiment, which is used to draw the zero-sequence current of the line switch in the fault schematic. At the same time, a judgment program unit is also designed to mark the line switch with the maximum zero-sequence current of the line switch as the pre-sequence switch of the fault point, and draw the pre-sequence switch mark of the fault point in the fault schematic. The principle of this design is that when a grounding fault occurs in the ungrounded distribution network, the zero-sequence current of the non-fault line flows to the earth through the ground capacitance, and then returns to the line from the grounding point through the busbar. The fault 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 earth, and the fault line, but the zero-sequence current before and after grounding is opposite. So it can be concluded that the zero-sequence current before the grounding point of the fault line is the sum of the zero-sequence current of the front part of the line and the zero-sequence current of all non-fault lines, and its amplitude is the largest in the whole network, and gradually decreases as the grounding point moves toward the busbar, and finally becomes the sum of the zero-sequence current of the non-fault line. The zero-sequence current after the grounding point of the fault line is the zero-sequence current of the rear part of the line. Considering that this part of the line is short, its amplitude is close to 0. Therefore, we only need to find the line switch with the maximum zero-sequence current and mark it as the preceding switch of the fault point in the fault diagram to know the location of the fault point. The location of the fault point is between the preceding switch of the fault point and the adjacent line switch far away from the busbar.

[0028] After knowing the location of the fault point, the technicians can remotely open and close the line switch through the switch remote control submodule of the processing system of this embodiment. By initiating an opening and closing signal to the line switch through wireless communication, remote control of the line switch within 100 kilometers can be achieved, so that the fault point can be powered off and isolated in time when a single-phase grounding fault occurs.

[0029] According to the above, when a single-phase grounding fault occurs, the steps of using the processing system of this embodiment to process are: S1: Obtain electrical quantities and grid topology information; S2: After receiving the single-phase ground fault signal, the fault line selection is determined based on the electrical quantity to determine the fault line; S3: Find the grid topology information of the fault line to generate a fault diagram for fault handling. The fault diagram connects the busbar and the outgoing line switch associated with the busbar through connecting lines, and connects the outgoing line switch with the line switch associated with the outgoing line switch to present the structure of the grid. The fault diagram also has a preceding switch mark of the fault point, which is determined by the fault handling module according to the electrical quantity.

[0030] Specifically, the method for sending a single-phase ground fault signal includes: comparing the single-phase voltage of the station switch with a set threshold interval, and sending the single-phase ground fault signal when the single-phase switch voltage in the station does not belong to the threshold interval.

[0031] Specifically, the method for fault line selection includes: calculating the line fault probability according to a probability formula, and taking the line with the maximum line fault probability as the fault line.

[0032] Specifically, the method for finding the grid topology information of the fault line includes: finding the bus-outgoing switch association relationship to determine the bus associated with the fault line and drawing the bus associated with the fault line in the fault diagram.

[0033] Specifically, the outgoing switch-line switch association relationship is searched to determine the line switch associated with the outgoing switch of the faulty line, and the line switch associated with the outgoing switch of the faulty line is drawn in the fault diagram.

[0034] Specifically, the switch-terminal association relationship is searched to determine the terminals associated with the outgoing switch of the faulty line and the terminals associated with the line switch, and the terminals associated with the outgoing switch of the faulty line and the terminals associated with the line switch are drawn in the fault diagram, and connecting lines are drawn according to the terminal-terminal connection relationship.

[0035] Specifically, the method for determining the preceding sequence switch mark of the fault point includes: drawing the zero sequence current of the line switch in the fault diagram; The line switch whose zero-sequence current is the maximum is marked as the preceding switch of the fault point, and the mark of the preceding switch of the fault point is drawn in the fault diagram.

[0036] Obviously, the embodiments described above are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0037] It should be understood that when the terms "first", "second", etc. are used in the claims, specification and drawings of the present application, they are only used to distinguish different objects, rather than to describe a specific order. The terms "include" and "comprise" used in the specification and claims of the present application indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections.

Claims

1. A processing system for a single-phase grounding fault in a distribution network, characterized in that: Includes data layer and 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, the electrical quantities include line switch zero-sequence current, and the power grid structure storage module is used to provide power grid topology information to the service layer; The service layer includes a fault processing module, which is used to perform fault line selection judgment according to the electrical quantity after receiving a single-phase grounding fault signal to determine the fault line, and to find the power grid topology information of the fault line to generate a fault diagram for fault processing. The fault diagram connects the busbar and the outgoing switch associated with the busbar through a connecting line, and connects the outgoing switch with the line switch associated with the outgoing switch to present the structure of the power grid. The fault diagram also has a fault point preceding switch mark, and the fault point preceding switch mark is determined by the fault processing module according to the zero-sequence current of the line switch.

2. The processing system according to claim 1, characterized in that The electrical quantity includes the single-phase voltage of the station switch, and the service layer also includes a fault monitoring module for comparing the single-phase voltage of the station switch with a set threshold range. When the single-phase switch voltage 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 electrical quantities include outgoing line phase current and outgoing line reactive power. The fault processing module is provided with a fault line selection submodule for performing fault line selection judgment according to the outgoing line phase current and the outgoing line reactive power to determine the faulty line.

4. The processing system according to claim 3, characterized in that The fault line selection submodule is provided with a calculation program unit for calculating the line fault probability according to a probability formula, and taking the line with the maximum line fault probability as the fault line. The probability formula is: in, For Line i The line failure probability, Indicates line i The proportion of the outgoing phase current change before and after the fault in all outgoing phase current changes, Indicates line i The proportion of the reactive power change of the outgoing line before and after the fault in all the reactive power changes of the outgoing line, m and n is the weight parameter set, m ∈[0,1], n ∈[0,1], m + n =1.

5. The processing system according to claim 1, characterized in that The grid topology information includes a busbar-outlet switch association relationship, an outlet switch-line switch association relationship, a switch-switch terminal association relationship, and a terminal-terminal connection relationship; The fault processing module is provided with a schematic diagram generating submodule for querying the power grid topology to determine the bus, line switch and switch terminal associated with the fault line, and drawing the fault schematic diagram according to the bus, line switch and switch terminal.

6. The processing system according to claim 5, characterized in that The schematic diagram generation submodule is provided with a busbar drawing program unit, which is used to search the busbar-outgoing switch association relationship to determine the busbar associated with the fault line and draw the busbar associated with the fault line in the fault schematic diagram; The schematic diagram generating submodule is also provided with a switch drawing program unit, which is used to search the outgoing line switch-line switch association relationship to determine the line switch associated with the fault line and draw the line switch associated with the fault line in the fault schematic diagram; The schematic diagram generating submodule is also provided with a connection line drawing program unit, which is used to search the switch-terminal association relationship to determine the terminal associated with the outgoing switch of the fault line and the terminal associated with the line switch, and draw the terminal associated with the outgoing switch of the fault line and the terminal associated with the line switch in the fault schematic diagram, and draw the connection lines according to the terminal-terminal connection relationship.

7. The processing system according to claim 5, characterized in that The schematic diagram generating submodule is also provided with a zero-sequence current drawing program unit for drawing the zero-sequence current of the line switch in the fault schematic diagram; The schematic diagram generating submodule is also provided with a judgment program unit for marking the line switch with the maximum zero-sequence current of the line switch as a preceding switch of the fault point, and drawing the preceding switch mark of the fault point in the fault schematic diagram.

8. The processing system according to claim 6, characterized in that The fault processing module is also provided with a switch remote control submodule for controlling the opening and closing of the line switch in the fault diagram.

9. A method for processing a single-phase grounding fault in a distribution network, which is operated by using the processing system according to claims 1 to 8, characterized in that: The following steps are involved: Obtain information on electrical quantities and grid topology; After receiving the single-phase ground fault signal, a fault line selection judgment is performed according to the electrical quantity to determine the fault line; The grid topology information of the fault line is searched to generate a fault diagram for fault processing. The fault diagram connects the busbar and the outgoing switch associated with the busbar through a connecting line, and connects the outgoing switch with the line switch associated with the outgoing switch to present the structure of the grid. The fault diagram also has a preceding switch mark of the fault point, and the preceding switch mark of the fault point is determined by the fault processing module according to the electrical quantity.

10. The processing method according to claim 9, characterized in that: The electrical quantities include the single-phase voltage of the station switch, the phase current of the outgoing line, the reactive power of the outgoing line and the zero-sequence current of the line switch, and the grid topology information includes the busbar-outgoing line switch association relationship, the outgoing line switch-line switch association relationship, the switch-switch terminal association relationship and the terminal-terminal connection relationship; The method for sending the single-phase ground fault signal comprises: comparing the single-phase voltage of the switch in the station with a set threshold interval, and sending the single-phase ground fault signal when the single-phase switch voltage in the station does not belong to the threshold interval; The method for fault line selection comprises: calculating the line fault probability according to a probability formula, and taking the line with the maximum line fault probability as the fault line, wherein the probability formula is: in, For Line i The line failure probability, Indicates line i The proportion of the outgoing phase current change before and after the fault in all outgoing phase current changes, Indicates line i The proportion of the reactive power change of the outgoing line before and after the fault in all the reactive power changes of the outgoing line, m and n is the weight parameter set, m ∈[0,1], n ∈[0,1], m + n =1; The method for searching for the grid topology information of the fault line comprises: searching for the bus-outgoing switch association relationship to determine the bus associated with the fault line and drawing the bus associated with the fault line in the fault diagram; Searching for the outgoing switch-line switch association relationship to determine the line switch associated with the outgoing switch of the faulty line and drawing the line switch associated with the outgoing switch of the faulty line in the fault diagram; Searching the switch-terminal association relationship to determine the terminal associated with the outgoing switch of the fault line and the terminal associated with the line switch, and drawing the terminal associated with the outgoing switch of the fault line and the terminal associated with the line switch in the fault diagram, and drawing connecting lines according to the terminal-terminal connection relationship; The method for determining the preceding switch mark of the fault point comprises: drawing the zero-sequence current of the line switch in the fault diagram; The line switch whose zero-sequence current is the maximum is marked as the preceding switch of the fault point, and the mark of the preceding switch of the fault point is drawn in the fault diagram.

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