Medium-voltage line single-phase disconnection fault comprehensive diagnosis method, system, equipment and medium

Abstract

The invention discloses a medium-voltage line single-phase disconnection fault comprehensive diagnosis method, system and device and a medium, and belongs to the technical field of circuit fault identification, and the method comprises the steps: determining the position of a switch, collecting and processing current data, comparing the current data with a preset rated line voltage, judging whether the voltage meets the requirements, carrying out the disconnection phase confirmation, and carrying out the fault diagnosis. And judging whether the fault is a single-phase broken line fault according to the current and the phase included angle. According to the method, the problem that a disconnection fault is misreported due to single-phase pull-in of a disconnecting link is solved by judging the closing position of the switch, and the angle precision problem caused by small non-disconnection phase current amplitude is considered, the non-disconnection phase current angle criterion is opened only when the non-disconnection phase current is greater than 2A, the disconnection missed judgment risk is reduced, and the accuracy of disconnection is improved. Compared with the situation that the single-phase broken line external fault is difficult to judge by the broken line of the branch line and the load is unbalanced, the judgment method of the single-phase broken line external fault is simple and accurate, the misjudgment and missed judgment risks are smaller, and meanwhile, the more complex broken line situation can be considered.

Description

Technical Field

[0001] This invention relates to the field of circuit fault identification technology, specifically to a comprehensive diagnostic method, system, equipment, and medium for single-phase open circuit faults in medium-voltage lines. Background Technology

[0002] In the power supply system, the medium-voltage distribution network plays a crucial role in connecting upstream and downstream, and its operational status directly affects the stability and reliability of power transmission. However, due to factors such as long-term equipment aging, harsh natural environment (such as lightning strikes, strong winds and rainstorms), and various human or animal-related accidental interferences, line breaks occur frequently, seriously threatening the normal operation of the power system.

[0003] Previous methods for identifying single-phase open-circuit faults outside the designated fault zone have several shortcomings. Some methods rely on complex equipment and high costs, limiting their widespread application in distribution networks of varying sizes. Other methods have stringent operating environment requirements, and misjudgments and missed judgments frequently occur under conditions of unbalanced three-phase loads or electromagnetic interference, failing to meet practical engineering needs. Furthermore, existing technologies are prone to misjudgment in complex open-circuit situations, such as when the open circuit is reconnected to a normal phase, when device sampling is abnormal, or when there is manual switching operations, seriously affecting the fault handling efficiency and power supply reliability of the power system. Summary of the Invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by this invention is: how to provide a comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines. Based on actual conditions, this method relies on logical judgment to determine single-phase open-circuit faults in medium-voltage lines. First, the switch position is determined, current data is collected and processed, and then compared with a preset rated line voltage to determine if it meets the requirements. Next, the open-circuit phase is confirmed, and the angle between the current and phase is used to determine if it is a single-phase open-circuit fault. This method effectively avoids false alarms of open-circuit faults due to single-phase opening or closing of the disconnector when the switch is open or the line is unloaded by first obtaining the switch position. It also considers the angle accuracy issues caused by the current amplitude of the non-open-circuit phase, avoiding the risk of missed open-circuit faults. It focuses on the identification of single-phase open-circuit faults outside the defined boundaries. The identification method only uses data for logical judgment, making the risk of missed faults smaller, while also taking into account more complex open-circuit situations.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines, comprising the following steps:

[0007] Acquire switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data; when the switch position status information determines that the switch is in the closed state, and the voltage sampling determined based on the three-phase voltage data and the zero-sequence voltage data meets a preset accuracy condition, determine the suspected open-circuit phase based on the three-phase voltage data; based on the phase current corresponding to the suspected open circuit and the phase current corresponding to the non-open circuit in the three-phase current data, and according to at least one preset fault criterion, confirm that a single-phase open circuit fault has occurred.

[0008] In a preferred embodiment of the comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines according to the present invention, the preset accuracy condition is that the ratio of the absolute value of the difference between the amplitude of the three-phase voltage vector sum calculated based on the three-phase voltage data and the amplitude of the zero-sequence voltage data to the amplitude of the zero-sequence voltage data is not greater than a first preset threshold. The beneficial effect of this preferred embodiment is that it verifies the accuracy of the sampled values ​​based on the switch being closed, ensuring the correctness of the phase voltage and zero-sequence voltage sampling, and avoiding false alarms in the open-circuit protection function due to abnormal sampling by the device.

[0009] As a preferred embodiment of the comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines according to the present invention, the step of determining the suspected open-circuit phase based on the three-phase voltage data includes: calculating three line voltages based on the three-phase voltage data; when the maximum value of the amplitude of the three line voltages is greater than the product of a first preset voltage multiple and the rated line voltage, and the minimum value of the amplitude of the three line voltages is less than the product of a second preset voltage multiple and the rated line voltage, it is determined that the three line voltages meet the accuracy condition.

[0010] As a preferred embodiment of the comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines described in this invention, the step of determining the suspected open-circuit phase based on the three-phase voltage data includes: determining the line voltage that generates the maximum value as the suspected open-circuit phase, and determining the other two line voltages as suspected non-open-circuit phases.

[0011] In a preferred embodiment of the comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines according to the present invention, the at least one preset fault criterion includes determining that the line is in an unloaded state when the amplitude of the phase current corresponding to the suspected open-circuit fault is not greater than a preset current threshold, and the amplitudes of the phase currents corresponding to the non-open-circuit faults are all greater than the preset current threshold. The beneficial effect of this preferred technical solution is that it considers the angle accuracy problem caused by the small amplitude of the non-open-circuit phase current. The non-open-circuit phase current angle criterion is only activated when the non-open-circuit phase current is greater than the preset current threshold. This avoids insufficient angle accuracy caused by the small phase current amplitude, which could lead to the failure to detect open-circuit faults, thus reducing the risk of missed open-circuit fault detection.

[0012] As a preferred embodiment of the comprehensive diagnostic method for single-phase open circuit faults in medium-voltage lines according to the present invention, the at least one preset fault criterion is that when the amplitude of the phase current corresponding to the suspected open circuit is not greater than a preset current threshold, and the amplitude of the phase current corresponding to the non-open circuit is not greater than the preset current threshold, the phase angle of the phase current corresponding to the non-open circuit is determined to be greater than a first preset angle threshold.

[0013] In a preferred embodiment of the comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines according to the present invention, the at least one preset fault criterion includes determining that when the amplitude of the phase current corresponding to the suspected open-circuit fault is greater than a preset current threshold, the difference between the phase of the phase current corresponding to the suspected open-circuit fault and the phase of the phase current with the middle amplitude in the three-phase current data is less than a second preset angle threshold, and determining that the phase angle of the phase current corresponding to the non-open-circuit fault is greater than the first preset angle threshold. The beneficial effect of this preferred embodiment is that, based on the identification of conventional open-circuit faults, the present invention adds criteria for identifying special open-circuit fault situations where the open circuit reconnects to a normal phase, thereby improving the accuracy and adaptability of identifying complex open-circuit fault situations on-site.

[0014] This invention provides a comprehensive diagnostic system for single-phase open circuit faults in medium-voltage lines.

[0015] To address the aforementioned technical problems, the present invention further provides the following technical solution: a comprehensive diagnostic system for single-phase open-circuit faults in medium-voltage lines, comprising: a data acquisition module for acquiring switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data; an information identification module for determining a suspected open-circuit phase based on the three-phase voltage data when the switch position status information indicates an on state and the voltage sampling determined based on the three-phase voltage data and the zero-sequence voltage data meets a preset accuracy condition; and a fault judgment module for confirming a single-phase open-circuit fault based on the phase current corresponding to the suspected open-circuit fault and the phase current corresponding to the non-open-circuit fault in the three-phase current data, and according to at least one preset fault criterion.

[0016] The present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, characterized in that the processor executes the computer program to implement the steps of the comprehensive diagnosis method for single-phase open circuit faults in medium-voltage lines.

[0017] The present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements the steps of the comprehensive diagnosis method for single-phase open circuit faults in medium-voltage lines, including: a data acquisition module for acquiring switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data;

[0018] The information identification module determines the suspected disconnected phase based on the three-phase voltage data when the switch position status information is determined to be in the closed state and the voltage sampling determined based on the three-phase voltage data and the zero-sequence voltage data meets the preset accuracy conditions.

[0019] The fault diagnosis module, based on the phase current corresponding to the suspected open circuit and the phase current corresponding to the non-open circuit in the three-phase current data, and according to at least one preset fault criterion, confirms that a single-phase open circuit fault has occurred.

[0020] The beneficial effects of this invention are as follows: By judging the closed position of the switch, false alarms of open circuit faults due to single-phase opening and closing of the disconnector are avoided. Considering the angle accuracy problem caused by the small amplitude of the non-open phase current, the non-open phase current angle criterion is opened only when the current of the non-open phase is greater than the preset current threshold, reducing the risk of missed open circuit faults. Compared with the single-phase open circuit fault outside the boundary, which is affected by the difficulty in judging branch line open circuits and load imbalance, the single-phase open circuit fault outside the boundary judgment method is simple, accurate and has a smaller risk of misjudgment and missed judgment, while also taking into account more complex open circuit situations. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The above is a flowchart of the overall diagnostic method for single-phase open circuit faults in medium-voltage lines provided in one embodiment of the present invention.

[0023] Figure 2 The flowchart illustrates the logical judgment of a comprehensive diagnostic method for single-phase open circuit faults in medium-voltage lines, as provided in an embodiment of the present invention. Detailed Implementation

[0024] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0025] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines, including:

[0026] S100: Acquire switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data.

[0027] S200: When the switch position status information is determined to be in the closed state, and the voltage sampling determined based on the three-phase voltage data and the zero-sequence voltage data meets the preset accuracy conditions, the suspected disconnected phase is determined based on the three-phase voltage data.

[0028] S300: Based on the phase currents corresponding to suspected open circuits and non-open circuits in the three-phase current data, and according to at least one preset fault criterion, confirm that a single-phase open circuit fault has occurred.

[0029] It should be noted that traditional methods rely on complex equipment and high costs, limiting their widespread application in distribution networks of different sizes. Furthermore, they are subject to stringent operating environment requirements, and misjudgments and missed judgments frequently occur under conditions of unbalanced three-phase loads or electromagnetic interference, failing to meet practical engineering needs. In addition, existing technologies pose a risk of misjudgment when dealing with complex disconnection situations, such as reconnection to a normal phase after a disconnection, abnormal device sampling, and manual switching operations, severely impacting the efficiency of power system fault handling and power supply reliability.

[0030] Therefore, to address the aforementioned issues, the diagnosis of single-phase open-circuit faults in medium-voltage lines is performed through steps S100-S300. First, switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data are acquired. Second, by confirming that the switch is in the closed position and that the voltage sampling determined based on the three-phase voltage data and zero-sequence voltage data meets the preset accuracy conditions, the suspected open-circuit phase is determined based on the three-phase voltage data. Finally, based on the phase current corresponding to the suspected open-circuit fault and the phase current corresponding to the non-open-circuit fault in the three-phase current data, and according to at least one preset fault criterion, a single-phase open-circuit fault is confirmed. This method avoids false alarms of open circuit faults due to single-phase opening and closing of disconnectors by judging the switch's closed position. Considering the angle accuracy problem caused by the small amplitude of the non-open phase current, the non-open phase current angle criterion is only enabled when all non-open phase currents are greater than the preset current threshold, reducing the risk of missed open circuit faults. Compared with single-phase open circuit faults outside the boundary, which are difficult to judge due to branch line open circuits and load imbalance, the method of judging single-phase open circuit faults outside the boundary is simple, accurate, and has a smaller risk of misjudgment and missed judgment. At the same time, it can also take into account more complex open circuit situations.

[0031] Example 2, refer to Figure 1 and Figure 2 This is the second embodiment of the present invention, which provides a comprehensive diagnostic method for single-phase open circuit faults in medium-voltage lines.

[0032] In this embodiment of the invention, step S100 involves acquiring switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data, and includes the following steps A1 and A2:

[0033] A1: Real-time acquisition of switch position status information and three-phase voltage, three-phase current, and zero-sequence voltage data at the location point on the power distribution line, and filtering to remove noise interference.

[0034] A2: Calculate the power frequency amplitude and phase of the three-phase voltage, current, and zero-sequence voltage using Fast Fourier Transform.

[0035] It should be noted that the switch judgment of the power distribution line is the foundation of all steps. The next step can only be carried out after confirming that the switch is in the closed position. This can avoid false alarms of line breakage when the switch is in the open position or the line is unloaded due to a single phase of the disconnector being pulled or closed.

[0036] In an optional implementation, step S100 can also utilize the Fast Fourier Transform algorithm with instantaneous values. Based on the instantaneous sampled values ​​of the three-phase voltage and current, the three-phase coordinate system is first transformed into a two-phase coordinate system to eliminate the coupling of the three-phase system. Then, it is transformed into a synchronous rotating coordinate system, at which point the power frequency AC component becomes a DC component. After filtering out the AC component with a low-pass filter, the amplitude and phase of the original signal can be calculated from the DC value, achieving fast and accurate electrical quantity measurement.

[0037] In another optional implementation, in step S100, the Fast Fourier Transform can also be used to detect the intersection of the voltage and current waveforms with the zero axis through a hardware comparator or software algorithm, record the zero-crossing time, calculate the signal period and frequency based on the time interval between adjacent zero-crossing points in the same direction, obtain the amplitude through a peak detection circuit, and calculate the phase through the time difference between the zero-crossing points of different phase sequence signals.

[0038] In this embodiment of the invention, step S200 determines the suspected disconnected phase based on the three-phase voltage data when the switch position status information is determined to be in the closed state and the voltage sampling determined based on the three-phase voltage data and the zero-sequence voltage data meets the preset accuracy conditions.

[0039] Specifically, the pre-set accuracy conditions are manifested in the following ways:

[0040]

[0041] in, Let a be the phase voltage. This is the voltage of phase b. For phase c voltage, It is the zero-sequence voltage.

[0042] It should be noted that the preset accuracy condition is the ratio of the absolute value of the difference between the amplitude of the three-phase voltage vector sum and the amplitude of the zero-sequence voltage to the amplitude of the zero-sequence voltage. When the ratio result is ≤5%, the suspected open-circuit phase can be determined based on the three-phase voltage data.

[0043] It should be noted that when the ratio result is greater than 5%, it indicates that the current phase voltage is abnormal and step S100 needs to be restarted.

[0044] Specifically, the suspected open circuit phase is determined based on the three-phase voltage data, including the following steps B1 and B2:

[0045] B1: Calculate the three line voltages based on the three-phase voltage data.

[0046] B2: When the maximum value of the three line voltages is greater than the product of the first preset voltage multiple and the rated line voltage, and the minimum value of the three line voltages is less than the product of the second preset voltage multiple and the rated line voltage, the line voltage that produces the maximum value is identified as the suspected open-circuit phase.

[0047] Specifically, in step B1, the line voltage amplitude is calculated using the three-phase voltage pass-through formula. The specific form of the three-phase pass-through formula is as follows:

[0048]

[0049] Pressure The difference is used to obtain the line voltage ca.

[0050] In step B2, the first preset voltage multiple is 0.9 and the second preset voltage multiple is 0.7.

[0051] It should be noted that when identifying a suspected broken phase, if the maximum value of the line voltage amplitude calculated by step B1 is not greater than the rated line voltage of the first preset voltage multiple and the minimum amplitude is less than the rated line voltage of the second preset voltage multiple, step S100 needs to be restarted.

[0052] In one optional implementation, the preset accuracy condition in step S200 can also be achieved by verifying the phase angle of the three-phase voltage. By calculating the actual phase angle between the three-phase voltages and determining whether the deviation from the theoretical value of 120° is within the preset ±5° tolerance range, if all phase angle differences are within the allowable range, the voltage sampling data is considered accurate and can be used for subsequent line break diagnosis.

[0053] In another optional implementation, the preset accuracy condition in step S200 can also be achieved by verifying the positive sequence voltage component, calculating the amplitude of the positive sequence component of the three-phase voltage using the symmetrical component method, and comparing the amplitude with the rated phase voltage of the system. When the positive sequence voltage amplitude is within the preset ±10% fluctuation range of the rated voltage, the voltage sampling data is determined to be valid.

[0054] In this embodiment of the invention, in step S300, based on the phase current corresponding to the suspected open circuit and the phase current corresponding to the non-open circuit in the three-phase current data, and according to at least one preset fault criterion, a single-phase open circuit fault is confirmed to have occurred.

[0055] It should be noted that when the amplitude of the phase current corresponding to the suspected open circuit is not greater than the preset current threshold, and the amplitude of the phase current corresponding to the non-open circuit is greater than the preset current threshold, the line is determined to be in an unloaded state and can be identified as a single-phase line fault.

[0056] The preset current threshold is 2A.

[0057] It should be noted that when the amplitude of the phase current corresponding to the suspected open circuit is not greater than the preset current threshold, and the amplitude of the phase current corresponding to the non-open circuit is not greater than the preset current threshold, it is determined that the phase angle of the phase current corresponding to the non-open circuit is greater than the first preset angle threshold, and it can be determined as a single-phase line fault.

[0058] It should be noted that if the phase angle of the phase current corresponding to the non-disconnected circuit is determined to be no greater than the first preset angle threshold, then step S100 needs to be restarted.

[0059] The first preset angle threshold is 170°.

[0060] It should be noted that when the amplitude of the phase current corresponding to the suspected open circuit is greater than the preset current threshold, the difference between the phase of the phase current corresponding to the suspected open circuit and the phase of the phase current with the middle amplitude in the three-phase current data is less than the second preset angle threshold, and the phase angle between the phase current corresponding to the non-open circuit is greater than the first preset angle threshold, it can be determined as a single-phase line fault.

[0061] The second preset angle threshold is 10°.

[0062] It should be noted that if the difference between the phase of the suspected disconnection phase current in the logical judgment and the phase of the phase current with the middle amplitude in the three-phase current data is not less than the second preset angle threshold, then step S100 needs to be executed again.

[0063] It should be noted that if the logic determines that the phase angle of the phase current corresponding to the non-disconnected circuit is not greater than the first preset angle threshold, then step S100 needs to be executed again.

[0064] In summary, this invention determines the switch position, collects and processes current data, and then compares it with a preset rated line voltage to determine if it meets the requirements. It then confirms the phase of the open circuit and determines whether it is a single-phase open circuit fault based on the angle between the current and the phase. This invention solves the problem of avoiding false alarms of open circuit faults due to single-phase opening and closing of the disconnector by judging the switch position. Considering the angle accuracy issue caused by the small amplitude of the non-open phase current, the non-open phase current angle criterion is only enabled when all non-open phase currents are greater than 2A, reducing the risk of missed open circuit faults. Compared to single-phase open circuit faults outside the boundary, which are difficult to identify due to branch line open circuits and load imbalance, the method for identifying single-phase open circuit faults outside the boundary is simple, accurate, and has a lower risk of misjudgment and missed judgment, while also taking into account more complex open circuit situations.

[0065] Example 3, referring to Figure 1 This is the third embodiment of the present invention. This embodiment provides a comprehensive diagnostic system for single-phase open-circuit faults in medium-voltage lines, including a data acquisition module for acquiring switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data; an information identification module for determining the suspected open-circuit phase based on the three-phase voltage data when the switch position status information is determined to be in the closed state and the voltage sampling determined based on the three-phase voltage data and the zero-sequence voltage data meets a preset accuracy condition; and a fault judgment module for confirming the occurrence of a single-phase open-circuit fault based on the phase current corresponding to the suspected open-circuit fault and the phase current corresponding to the non-open-circuit fault in the three-phase current data, and according to at least one preset fault criterion.

[0066] Example 4, the fourth embodiment of the present invention, differs from the previous three embodiments in that: if the function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, 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 the present invention. 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.

[0067] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0068] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0069] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0070] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines, characterized by: include, Acquire switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data; When the switch position status information is determined to be in the closed state, and the voltage sampling determined based on the three-phase voltage data and the zero-sequence voltage data meets the preset accuracy conditions, the suspected disconnected phase is determined based on the three-phase voltage data. Based on the phase currents corresponding to the suspected open circuit and the phase currents corresponding to the non-open circuit in the three-phase current data, and according to at least one preset fault criterion, a single-phase open circuit fault is confirmed to have occurred.

2. The comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines as described in claim 1, characterized in that, The preset accuracy condition is that the absolute value of the difference between the amplitude of the three-phase voltage vector sum calculated based on the three-phase voltage data and the amplitude of the zero-sequence voltage data, and the ratio of the absolute value of the difference to the amplitude of the zero-sequence voltage data, is not greater than a first preset threshold.

3. The comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines as described in claim 2, characterized in that, The step of determining the suspected open-circuit phase based on the three-phase voltage data includes: Three line voltages are calculated based on the three-phase voltage data; If the maximum value of the amplitude of the three line voltages is greater than the product of the first preset voltage multiple and the rated line voltage, and the minimum value of the amplitude of the three line voltages is less than the product of the second preset voltage multiple and the rated line voltage, then the three line voltages are determined to meet the accuracy condition.

4. The comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines as described in claim 3, characterized in that, The step of determining the suspected open-circuit phase based on the three-phase voltage data includes: The line voltage that produces the maximum value is identified as the suspected open-circuit phase, and the other two line voltages are identified as suspected non-open-circuit phases.

5. The comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines as described in claim 4, characterized in that, The at least one preset fault criterion includes determining that the line is in an unloaded state when the amplitude of the phase current corresponding to the suspected open circuit is not greater than a preset current threshold, and the amplitude of the phase current corresponding to the non-open circuit is greater than the preset current threshold.

6. The comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines as described in claim 5, characterized in that, The at least one preset fault criterion is that when the amplitude of the phase current corresponding to the suspected open circuit is not greater than a preset current threshold, and the amplitude of the phase current corresponding to the non-open circuit is not greater than the preset current threshold, the phase angle of the phase current corresponding to the non-open circuit is determined to be greater than a first preset angle threshold.

7. The comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines as described in claim 6, characterized in that, The at least one preset fault criterion includes determining that when the amplitude of the phase current corresponding to the suspected open circuit is greater than a preset current threshold, the difference between the phase of the phase current corresponding to the suspected open circuit and the phase of the phase current with the middle amplitude in the three-phase current data is less than a second preset angle threshold, and determining that the phase angle of the phase current corresponding to the non-open circuit is greater than the first preset angle threshold.

8. A comprehensive diagnostic system for single-phase open-circuit faults in medium-voltage lines, employing the comprehensive diagnostic method for single-phase open-circuit faults in medium-voltage lines as described in any one of claims 1 to 7, characterized in that, include: The data acquisition module acquires switch position status information, three-phase voltage data, three-phase current data, and zero-sequence voltage data. The information identification module determines the suspected disconnected phase based on the three-phase voltage data when the switch position status information is determined to be in the closed state and the voltage sampling determined based on the three-phase voltage data and the zero-sequence voltage data meets the preset accuracy conditions. The fault diagnosis module, based on the phase current corresponding to the suspected open circuit and the phase current corresponding to the non-open circuit in the three-phase current data, and according to at least one preset fault criterion, confirms that a single-phase open circuit fault has occurred.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the comprehensive diagnostic method for single-phase open circuit faults in medium-voltage lines as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the comprehensive diagnostic method for single-phase open circuit faults in medium-voltage lines as described in any one of claims 1 to 7.

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