Differential single-phase earth fault segment selection method considering bus grounding mode

Abstract

The invention relates to a differentiated single-phase earth fault segment selection method considering a bus grounding mode. The method comprises the following steps of collecting zero-sequence voltage of a power distribution network and phase voltage of each bus; based on the zero-sequence voltage of the power distribution network and the phase voltage of each bus, judging whether each bus has a grounding fault or not; obtaining grounding modes of the grounding fault bus, wherein the grounding modes comprise a small resistance grounding mode, an arc suppression coil grounding mode and a non-grounding mode; recording signals and zero-sequence current signals of all equipment under the grounding fault bus are collected; for a grounding fault bus in a small resistance grounding mode, fault section selection is carried out through a zero sequence tripping method based on a zero sequence current signal; for a grounding fault bus in an arc suppression coil grounding mode, fault section selection is carried out through a transient state wave recording centralized judgment and research method based on wave recording signals; for a grounding fault bus in an ungrounded mode, fault section selection is carried out through a zero sequence amplitude comparison method based on the zero sequence current signal.

Description

Technical Field

[0001] This invention relates to a differentiated single-phase grounding fault segmentation method that takes into account the bus grounding method, and belongs to the field of power distribution automation technology. Background Technology

[0002] Single-phase grounding faults in distribution networks are a common type of fault in power systems. Accurate segment selection is of great significance for improving power supply reliability and reducing the scope of power outages.

[0003] Traditional line selection methods often rely on comparison of zero-sequence current amplitude or phase. However, the fault characteristics differ significantly under different bus grounding methods (such as low-resistance grounding, arc suppression coil grounding, and ungrounded systems). A single segment selection strategy is difficult to adapt to all systems, resulting in low segment selection accuracy.

[0004] Existing methods often ignore the differences in grounding methods and lack a unified and intelligent judgment mechanism. In particular, the transient process in the arc suppression coil grounding system is complex, and traditional methods are easily affected by interference.

[0005] Therefore, there is an urgent need for a differentiated segment selection method that can adapt to different grounding methods and integrate multi-source information. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention proposes a differentiated single-phase grounding fault segment selection method that considers the bus grounding method.

[0007] The technical solution of the present invention is as follows: On the one hand, the present invention provides a differentiated single-phase grounding fault segment selection method considering the bus grounding method, comprising the following steps: Collect the zero-sequence voltage of the distribution network and the phase voltage of each bus; Determine whether a grounding fault has occurred on each bus based on the zero-sequence voltage of the distribution network and the phase voltage of each bus. The grounding method of the grounding fault busbar is obtained, including low-resistance grounding, arc suppression coil grounding, and no grounding. Collect waveform signals and zero-sequence current signals from all devices under the ground fault bus. For ground fault buses with low resistance grounding, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence tripping method. For ground fault buses with arc suppression coil grounding, fault segment selection is performed based on the recorded waveform signal using the transient waveform centralized judgment method; For ungrounded ground fault busbars, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method.

[0008] Preferably, for any busbar, a ground fault is determined to exist on that busbar when the following conditions are met simultaneously: The zero-sequence voltage in the distribution network is greater than the preset upper limit threshold for zero-sequence voltage. Currently, there is a single-phase voltage on the bus that is less than or equal to the preset lower voltage threshold, while the voltages of the other two phases are greater than the preset lower voltage threshold.

[0009] Preferably, for a ground fault bus with a low-resistance grounding method, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence tripping method. The specific steps are as follows: Collect the zero-sequence current of all feeders under the ground fault bus within a preset time period, extract the maximum value of the zero-sequence current of all feeders within the preset time period, and obtain the reference value of the zero-sequence current of each feeder. Select the feeder corresponding to the maximum zero-sequence current reference value as the faulty line, and then select a section of the faulty line: Collect the zero-sequence current of each switch in the faulty line within a preset time period, extract the maximum value of the zero-sequence current of all switches within the preset time period, and obtain the reference value of the zero-sequence current of each switch. For each pair of adjacent switches in the faulty line, the zero-sequence current reference values ​​of the upstream and downstream switches in each pair of adjacent switches are compared. If the zero-sequence current reference value of the upstream switch is greater than the preset multiple of the downstream switch, then the section from the upstream switch to the downstream switch is considered to be the faulty section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

[0010] Preferably, for a ground fault busbar with an arc suppression coil grounding method, fault segment selection is performed based on the recorded waveform signal using a transient waveform centralized analysis method. The specific steps are as follows: Collect the waveforms of all feeder outgoing switches under the ground fault bus, extract the single-phase ground fault characteristic value of each feeder outgoing switch waveform, and select the feeder with the largest single-phase ground fault characteristic value as the faulty line segment for selection: Collect the waveforms of all switches under the faulty line and extract the characteristic values ​​of the waveforms of each switch under the faulty line. For each pair of adjacent switches in the faulty line, the waveform characteristic values ​​of the upstream switch and the downstream switch in each pair of adjacent switches are compared. If the waveform characteristic value of the upstream switch is greater than a preset multiple of the downstream switch, the section from the upstream switch to the downstream switch is considered to be the faulty section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

[0011] Preferably, for a ground fault busbar in an ungrounded manner, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method. The specific steps are as follows: Collect the zero-sequence current mutation values ​​of all feeders under the ground fault bus, select the feeder with the largest zero-sequence current mutation value as the faulty line, and select the faulty line segment: Collect the zero-sequence current mutation of all switches on the ground fault bus. For each pair of adjacent switches in the fault line, compare the zero-sequence current mutation of the upstream switch and the downstream switch in each pair of adjacent switches. If the zero-sequence current mutation of the upstream switch is greater than the preset multiple of the downstream switch, the section from the upstream switch to the downstream switch is considered to be the fault section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

[0012] On the other hand, the present invention also provides a differentiated single-phase grounding fault segmentation system that takes into account the bus grounding method, including a data acquisition module, a fault judgment module, a grounding method acquisition module and a fault segmentation module; The data acquisition module is used to acquire the zero-sequence voltage of the distribution network and the phase voltage of each bus, as well as the waveform recording signal and zero-sequence current signal of all equipment under the ground fault bus. The fault judgment module is used to determine whether a grounding fault has occurred on each bus based on the zero-sequence voltage of the distribution network and the phase voltage of each bus. The grounding mode acquisition module is used to acquire the grounding mode of the ground fault bus, which includes low resistance grounding mode, arc suppression coil grounding mode and no grounding mode; The fault segmentation module is used to perform fault segmentation for ground fault buses with different grounding methods. For ground fault buses with low resistance grounding, fault segmentation is performed based on the zero-sequence current signal using the zero-sequence tripping method. For ground fault buses with arc suppression coil grounding, fault segmentation is performed based on the waveform recording signal using the transient waveform recording centralized judgment method. For ground fault buses with ungrounded grounding, fault segmentation is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method.

[0013] Preferably, for any busbar, a ground fault is determined to exist on that busbar when the following conditions are met simultaneously: The zero-sequence voltage in the distribution network is greater than the preset upper limit threshold for zero-sequence voltage. Currently, there is a single-phase voltage on the bus that is less than or equal to the preset lower voltage threshold, while the voltages of the other two phases are greater than the preset lower voltage threshold.

[0014] In another aspect, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described in the present invention.

[0015] In another aspect, the present invention also provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method described in the present invention.

[0016] The present invention has the following beneficial effects: 1. Based on the fault characteristics of different bus grounding methods, this invention adopts the zero-sequence tripping method, the transient waveform centralized analysis method, and the zero-sequence amplitude comparison method to achieve accurate fault segment selection and overcome the problem of poor applicability of traditional methods in different systems.

[0017] 2. This invention comprehensively utilizes multiple signals such as zero-sequence voltage, phase voltage, recorded waveform, and zero-sequence current to improve the reliability and anti-interference capability of fault identification. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0021] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0023] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0024] See Figure 1 A differentiated single-phase grounding fault segment selection method considering bus grounding mode includes the following steps: Collect the zero-sequence voltage of the distribution network and the phase voltage of each bus; Determine whether a grounding fault has occurred on each bus based on the zero-sequence voltage of the distribution network and the phase voltage of each bus. The grounding method of the grounding fault busbar is obtained, including low-resistance grounding, arc suppression coil grounding, and no grounding. Collect waveform signals and zero-sequence current signals from all devices under the ground fault bus. For ground fault buses with low resistance grounding, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence tripping method. For ground fault buses with arc suppression coil grounding, fault segment selection is performed based on the recorded waveform signal using the transient waveform centralized judgment method; For ungrounded ground fault busbars, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method.

[0025] In one specific embodiment, the distribution master station monitors the operation status of the distribution network in real time. When the distribution master station detects abnormal signals such as zero-sequence voltage over-limit signal, phase voltage over-limit signal, bus grounding alarm signal, line selection device line selection signal, and arc suppression coil line selection signal, it initiates bus grounding fault judgment after a period of delay and filtering out interference information.

[0026] In some embodiments, for any busbar, a ground fault is determined to exist when the following conditions are met simultaneously: The zero-sequence voltage in the distribution network is greater than the preset upper limit threshold for zero-sequence voltage. Currently, there is a single-phase voltage on the bus that is less than or equal to the preset lower voltage threshold, while the voltages of the other two phases are greater than the preset lower voltage threshold.

[0027] In one specific embodiment, the low-resistance grounding system has fault characteristics of large zero-sequence current amplitude, constant capacitive current direction, and obvious steady-state characteristics. Arc suppression coil grounding systems are characterized by inductive current overcompensated capacitive current, small zero-sequence current which is inductive, current phase opposite, and complex transient processes. Ungrounded systems are characterized by faults where non-faulted lines are dominated by capacitive currents and the zero-sequence current is larger than that of arc suppression coil grounded systems.

[0028] In some embodiments, for a ground fault busbar with low-resistance grounding, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence tripping method. When a single-phase ground fault occurs on a low-resistance grounding busbar, the zero-sequence current flowing through the lost-ground line is the largest, and the zero-sequence current upstream of the fault point is much larger than the sudden change in zero-sequence current downstream of the fault point. During the fault segment location, both substation switches and external switches participate in the selection process. The specific steps are as follows: Collect the zero-sequence current of all feeders under the ground fault bus within a preset time period, extract the maximum value of the zero-sequence current of all feeders within the preset time period, and obtain the reference value of the zero-sequence current of each feeder. Select the feeder corresponding to the maximum zero-sequence current reference value as the faulty line, and then select a section of the faulty line: Collect the zero-sequence current of each switch in the faulty line within a preset time period, extract the maximum value of the zero-sequence current of all switches within the preset time period, and obtain the reference value of the zero-sequence current of each switch. For each pair of adjacent switches in the faulty line, the zero-sequence current reference values ​​of the upstream and downstream switches in each pair of adjacent switches are compared. If the zero-sequence current reference value of the upstream switch is greater than the preset multiple of the downstream switch, then the section from the upstream switch to the downstream switch is considered to be the faulty section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

[0029] In some embodiments, for a ground fault busbar with an arc suppression coil grounding method, fault segment selection is performed based on the recorded waveform signal using a transient waveform centralized analysis method. The specific steps are as follows: Collect the waveforms of all feeder outgoing switches under the ground fault bus, extract the single-phase ground fault characteristic value of each feeder outgoing switch waveform, and select the feeder with the largest single-phase ground fault characteristic value as the faulty line segment for selection: Collect the waveforms of all switches under the faulty line and extract the characteristic values ​​of the waveforms of each switch under the faulty line. For each pair of adjacent switches in the faulty line, the waveform characteristic values ​​of the upstream switch and the downstream switch in each pair of adjacent switches are compared. If the waveform characteristic value of the upstream switch is greater than a preset multiple of the downstream switch, the section from the upstream switch to the downstream switch is considered to be the faulty section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

[0030] In some embodiments, for ungrounded busbars with ground faults, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method. When a single-phase ground fault occurs on an ungrounded busbar, the zero-sequence current change flowing through the lost-ground line is the largest, and the zero-sequence current change upstream of the fault point is much larger than the zero-sequence current change downstream of the fault point. Fault segment location is then performed using both substation switches and external switches. The specific steps are as follows: Collect the zero-sequence current mutation values ​​of all feeders under the ground fault bus, select the feeder with the largest zero-sequence current mutation value as the faulty line, and select the faulty line segment: Collect the zero-sequence current mutation of all switches on the ground fault bus. For each pair of adjacent switches in the fault line, compare the zero-sequence current mutation of the upstream switch and the downstream switch in each pair of adjacent switches. If the zero-sequence current mutation of the upstream switch is greater than the preset multiple of the downstream switch, the section from the upstream switch to the downstream switch is considered to be the fault section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

[0031] In some embodiments, a differentiated single-phase grounding fault segmentation system considering bus grounding mode is proposed, including a data acquisition module, a fault judgment module, a grounding mode acquisition module, and a fault segmentation module. The data acquisition module is used to acquire the zero-sequence voltage of the distribution network and the phase voltage of each bus, as well as the waveform recording signal and zero-sequence current signal of all equipment under the ground fault bus. The fault judgment module is used to determine whether a grounding fault has occurred on each bus based on the zero-sequence voltage of the distribution network and the phase voltage of each bus. The grounding mode acquisition module is used to acquire the grounding mode of the ground fault bus, which includes low resistance grounding mode, arc suppression coil grounding mode and no grounding mode; The fault segmentation module is used to perform fault segmentation for ground fault buses with different grounding methods. For ground fault buses with low resistance grounding, fault segmentation is performed based on the zero-sequence current signal using the zero-sequence tripping method. For ground fault buses with arc suppression coil grounding, fault segmentation is performed based on the waveform recording signal using the transient waveform recording centralized judgment method. For ground fault buses with ungrounded grounding, fault segmentation is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method.

[0032] In some embodiments, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method as described in any embodiment of the present invention.

[0033] In some embodiments, a computer-readable storage medium is provided on which a computer program is stored, which, when executed by a processor, implements the method as described in any embodiment of the present invention.

[0034] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0035] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0036] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0037] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0038] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A differentiated single-phase grounding fault segment selection method considering busbar grounding methods, characterized in that, Includes the following steps: Collect the zero-sequence voltage of the distribution network and the phase voltage of each bus; Determine whether a grounding fault has occurred on each bus based on the zero-sequence voltage of the distribution network and the phase voltage of each bus. Obtain the grounding method of the grounding fault bus, including low-resistance grounding, arc suppression coil grounding, and ungrounded grounding; Collect waveform signals and zero-sequence current signals from all devices under the ground fault bus. For ground fault buses with low resistance grounding, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence tripping method. For ground fault buses with arc suppression coil grounding, fault segment selection is performed based on the recorded waveform signal using the transient waveform centralized judgment method; For ungrounded ground fault busbars, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method.

2. The differentiated single-phase grounding fault segment selection method considering busbar grounding mode according to claim 1, characterized in that, For any busbar, a ground fault is determined to exist on that busbar when the following conditions are met simultaneously: The zero-sequence voltage in the distribution network is greater than the preset upper limit threshold for zero-sequence voltage. Currently, there is a single-phase voltage on the bus that is less than or equal to the preset lower voltage threshold, while the voltages of the other two phases are greater than the preset lower voltage threshold.

3. The differentiated single-phase grounding fault segment selection method considering busbar grounding mode according to claim 1, characterized in that, For a ground fault bus with a low-resistance grounding method, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence tripping method. The specific steps are as follows: Collect the zero-sequence current of all feeders under the ground fault bus within a preset time period, extract the maximum value of the zero-sequence current of all feeders within the preset time period, and obtain the reference value of the zero-sequence current of each feeder. Select the feeder corresponding to the maximum zero-sequence current reference value as the faulty line, and then select a section of the faulty line: Collect the zero-sequence current of each switch in the faulty line within a preset time period, extract the maximum value of the zero-sequence current of all switches within the preset time period, and obtain the reference value of the zero-sequence current of each switch. For each pair of adjacent switches in the faulty line, the zero-sequence current reference values ​​of the upstream and downstream switches in each pair of adjacent switches are compared. If the zero-sequence current reference value of the upstream switch is greater than the preset multiple of the downstream switch, then the section from the upstream switch to the downstream switch is considered to be the faulty section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

4. The differentiated single-phase grounding fault segment selection method considering busbar grounding mode according to claim 1, characterized in that, For ground fault buses using arc suppression coil grounding, fault segment selection is performed based on the recorded waveform signal using a transient waveform centralized analysis method. The specific steps are as follows: Collect the waveforms of all feeder outgoing switches under the ground fault bus, extract the single-phase ground fault characteristic value of each feeder outgoing switch waveform, and select the feeder with the largest single-phase ground fault characteristic value as the faulty line segment for selection: Collect the waveforms of all switches under the faulty line and extract the characteristic values ​​of the waveforms of each switch under the faulty line. For each pair of adjacent switches in the faulty line, the waveform characteristic values ​​of the upstream switch and the downstream switch in each pair of adjacent switches are compared. If the waveform characteristic value of the upstream switch is greater than a preset multiple of the downstream switch, the section from the upstream switch to the downstream switch is considered to be the faulty section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

5. The differentiated single-phase grounding fault segment selection method considering busbar grounding mode according to claim 1, characterized in that, For ungrounded ground fault buses, fault segment selection is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method. The specific steps are as follows: Collect the zero-sequence current mutation values ​​of all feeders under the ground fault bus, select the feeder with the largest zero-sequence current mutation value as the faulty line, and select the faulty line segment: Collect the zero-sequence current mutation of all switches on the ground fault bus. For each pair of adjacent switches in the fault line, compare the zero-sequence current mutation of the upstream switch and the downstream switch in each pair of adjacent switches. If the zero-sequence current mutation of the upstream switch is greater than the preset multiple of the downstream switch, the section from the upstream switch to the downstream switch is considered to be the fault section. If no fault section is found when comparing all adjacent switch pairs, then the fault section is considered to be located at the end of the faulty line, and the end switch is the upper boundary of the fault section.

6. A differentiated single-phase grounding fault segmentation system considering busbar grounding methods, characterized in that, It includes a data acquisition module, a fault diagnosis module, a grounding method acquisition module, and a fault segment selection module; The data acquisition module is used to acquire the zero-sequence voltage of the distribution network and the phase voltage of each bus, as well as the waveform recording signal and zero-sequence current signal of all equipment under the ground fault bus. The fault judgment module is used to determine whether a grounding fault has occurred on each bus based on the zero-sequence voltage of the distribution network and the phase voltage of each bus. The grounding mode acquisition module is used to acquire the grounding mode of the ground fault bus, which includes low resistance grounding mode, arc suppression coil grounding mode and no grounding mode; The fault segmentation module is used to perform fault segmentation for ground fault buses with different grounding methods. For ground fault buses with low resistance grounding, fault segmentation is performed based on the zero-sequence current signal using the zero-sequence tripping method. For ground fault buses with arc suppression coil grounding, fault segmentation is performed based on the waveform recording signal using the transient waveform recording centralized judgment method. For ground fault buses with ungrounded grounding, fault segmentation is performed based on the zero-sequence current signal using the zero-sequence amplitude comparison method.

7. A differentiated single-phase grounding fault segmentation system considering busbar grounding methods according to claim 6, characterized in that, For any busbar, a ground fault is determined to exist on that busbar when the following conditions are met simultaneously: The zero-sequence voltage in the distribution network is greater than the preset upper limit threshold for zero-sequence voltage. Currently, there is a single-phase voltage on the bus that is less than or equal to the preset lower voltage threshold, while the voltages of the other two phases are greater than the preset lower voltage threshold.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 5.

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