Fault type determination method and device for cable joint sheath

Abstract

The invention discloses a fault type judgment method and device for a cable joint sheath, and relates to the field of cable fault analysis, and the method comprises the steps: obtaining a fault type set based on the characteristic abnormality analysis result of voltage and current waveforms, the fault types comprise short circuit between grounding wires in the grounding box, wiring errors, breakdown of an insulating partition plate and multi-point grounding short circuit of a protective layer; determining a target fault type with the highest fault probability from the fault type set; establishing a local simulation model, simulating the configuration of the cable joint and the grounding box under the target fault type by adopting the local simulation model, and outputting a local simulation result; and comparing the local simulation result with the voltage and current waveform tested by the cable joint, verifying whether the target fault type is a final type which causes the fault of the sheath of the cable joint, and obtaining a fault verification result. According to the invention, the technical problem that the fault type cannot be accurately determined in the case of abnormal voltage and current of the cable joint sheath in the related technology is solved.

Description

Technical Field

[0001] This invention relates to the field of cable fault analysis or other related fields, and more specifically, to a method and apparatus for determining the fault type of a cable joint sheath. Background Technology

[0002] With the continuous development and upgrading of power systems, power cables play an increasingly important role in modern power grids, especially high-voltage cable lines of 110kV and above (most 110kV and above power cables are single-core cables). Their stable operation is crucial to ensuring the safety and reliability of power supply. However, due to environmental factors, design defects, or improper construction, high-voltage cables and their accessories may fail. Abnormal sheath voltage and current at cable joints are particularly prominent, which not only affect the normal operation of the power system but may also lead to safety accidents.

[0003] In related technologies, the widespread use of single-core cables leads to a high sheath voltage due to electromagnetic induction during operation, resulting in sheath current. To prevent this voltage from threatening equipment and personnel, the sheath needs to be grounded. In practice, long-distance high-voltage cables commonly employ cross-interconnection grounding, where the metal sheaths of the three phases are connected at regular intervals, and phase-switching grounding is used to balance the sheath current and reduce the sheath voltage. However, in cross-interconnection grounding systems, abnormal increases in sheath current and overheating of the grounding wires occur frequently, posing challenges to the safe operation of cable lines.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This invention provides a method and apparatus for determining the fault type of a cable joint sheath, thereby at least solving the technical problem in the related art of being unable to accurately determine the fault type in scenarios of abnormal voltage and current in the cable joint sheath.

[0006] According to one aspect of the present invention, a method for determining the fault type of a cable joint sheath is provided, comprising: obtaining a fault type set based on the characteristic anomaly analysis results of voltage and current waveforms, wherein the fault type in the fault type set includes at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation partition breakdown, and multiple-point short circuit to ground in the sheath; determining the target fault type with the highest fault probability from the fault type set; establishing a local simulation model, simulating the cable joint and grounding box configuration under the target fault type using the local simulation model, and outputting local simulation results; comparing the local simulation results with the voltage and current waveforms tested at the cable joint, verifying whether the target fault type is the final type causing the cable joint sheath to fail, and obtaining a fault verification result.

[0007] Optionally, the step of obtaining a set of fault types based on the characteristic anomaly analysis results of voltage and current waveforms includes: analyzing the sheath voltage and current waveforms on the left and right sides of the cable joint, identifying patterns in which the current or voltage in at least two phases exhibits abnormal characteristics, and obtaining characteristic anomaly analysis results, wherein the abnormal characteristic patterns include: the presence of interphase low resistance forming an internal equipotential point at the fault joint, resulting in local current backflow; and based on the characteristic anomaly analysis results, determining the fault types that cause the abnormal characteristics of the cable joint sheath, and obtaining the set of fault types.

[0008] Optionally, the step of determining the target fault type with the highest fault probability from the set of fault types includes: when the fault type is a short circuit between grounding wires inside the grounding box, analyzing whether the current amplitudes on the left and right sides of the short circuit point inside the grounding box are equal, and obtaining a first fault probability based on the first analysis result; or when the fault type is a wiring error, analyzing the short circuit state between the sheaths of the cables on the left and right sides of the cable joint, and obtaining a second fault probability based on the second analysis result; or when the fault type is a partition breakdown inside the insulation joint, checking the breakdown probability of the insulation partition of the cable joint sheath, and determining a third fault probability based on the partition breakdown probability value; when the fault type is a simultaneous short circuit between two phase sheaths and ground near the joint, evaluating the probability of multiple short circuits between the sheaths and ground, and determining a fourth fault probability; and selecting the fault type corresponding to the highest fault probability as the target fault type.

[0009] Optionally, the step of establishing a local simulation model includes: constructing a configuration model of cable joints and grounding boxes at the faulty joint and adjacent areas on a simulation software platform to obtain the local simulation model, wherein the local simulation model contains all key components that cause abnormal voltage and current characteristics.

[0010] Optionally, the step of outputting local simulation results includes: running the local simulation model, obtaining waveform data of cable joint sheath voltage and current under the target fault type, and outputting local simulation results.

[0011] Optionally, the step of comparing the local simulation results with the voltage and current waveforms tested at the cable joint includes: comparing the voltage and current waveforms in the local simulation results with the voltage and current waveforms obtained from the on-site test of the cable joint point by point to determine the similarity between the two waveforms.

[0012] Optionally, the step of obtaining the fault verification result includes: if the matching degree between the local simulation result and the tested voltage and current waveform is higher than a preset matching degree threshold, confirming that the target fault type is the final type leading to the cable joint sheath fault.

[0013] According to another aspect of the present invention, a fault type determination device for cable joint sheaths is also provided, comprising: a fault type analysis unit, configured to obtain a fault type set based on the characteristic anomaly analysis results of voltage and current waveforms, wherein the fault type in the fault type set includes at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation partition breakdown, and multiple-point short circuit to ground in the sheath; a fault type determination unit, configured to determine the target fault type with the highest fault probability from the fault type set; a simulation unit, configured to establish a local simulation model, use the local simulation model to simulate the cable joint and grounding box configuration under the target fault type, and output local simulation results; and a fault determination unit, configured to compare the local simulation results with the voltage and current waveforms tested at the cable joint, verify whether the target fault type is the final type causing the cable joint sheath to fail, and obtain a fault verification result.

[0014] Optionally, the fault type analysis unit includes: a current and voltage analysis module, used to analyze the sheath voltage and current waveforms on the left and right sides of the cable joint, identify patterns in which the current or voltage in at least two phases exhibits abnormal characteristics, and obtain characteristic anomaly analysis results, wherein the abnormal characteristic patterns include: the presence of low phase-to-phase resistance at the fault joint forming an internal equipotential point, resulting in local current backflow; and a fault type determination module, used to determine the fault type causing the abnormal characteristics of the cable joint sheath based on the characteristic anomaly analysis results, and obtain the fault type set.

[0015] Optionally, the fault type determination unit includes: a first fault probability analysis module, used to analyze whether the current amplitudes on the left and right sides of the short circuit point inside the grounding box are equal when the fault type is a short circuit between grounding wires inside the grounding box, and obtain a first fault probability based on the first analysis result; a second fault probability analysis module, used to analyze the short circuit state between the sheaths of the left and right cables of the cable joint when the fault type is a wiring error, and obtain a second fault probability based on the second analysis result; a third fault probability analysis module, used to check the breakdown probability of the insulating partition of the cable joint sheath when the fault type is a partition breakdown inside the insulating joint, and determine a third fault probability based on the partition breakdown probability value; a fourth fault probability analysis module, used to evaluate the probability of multiple short circuits to ground of the sheath when the fault type is a simultaneous short circuit between two phase sheaths and ground near the joint, and determine a fourth fault probability; and a fault type selection module, used to select the fault type corresponding to the highest fault probability as the target fault type.

[0016] Optionally, the simulation unit includes a model building module, used to build a configuration model of cable joints and grounding boxes in the faulty joint and adjacent areas on a simulation software platform to obtain the local simulation model, wherein the local simulation model contains all the key components that cause abnormal voltage and current characteristics.

[0017] Optionally, the simulation unit further includes a model running module, used to run the local simulation model, acquire waveform data of cable joint sheath voltage and current under the target fault type, and output local simulation results.

[0018] Optionally, the fault determination unit includes a voltage and current comparison module, used to compare the voltage and current waveforms in the local simulation results with the voltage and current waveforms obtained from the on-site test of the cable joint point by point to determine the similarity between the two waveforms.

[0019] Optionally, when the fault determination unit obtains the fault verification result, it includes: a fault type determination module, used to confirm that the target fault type is the final type leading to the cable joint sheath fault when the matching degree between the local simulation result and the tested voltage and current waveform is higher than a preset matching degree threshold.

[0020] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to execute the cable joint sheath fault type determination method described above.

[0021] According to another aspect of the present invention, an electronic device is also provided, including one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the cable joint sheath fault type determination method of any one of the above.

[0022] According to another aspect of the present invention, a computer program product is also provided, including a computer program that, when executed by a processor, implements the steps of the fault type determination method for cable joint sheaths as described in any one of the above embodiments.

[0023] In this disclosure, a set of fault types can be obtained based on the characteristic anomaly analysis results of voltage and current waveforms. The fault types in the set of fault types include at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation partition breakdown, and multiple short circuits to ground in the sheath. The target fault type with the highest probability is determined from the set of fault types. A local simulation model is established, and the cable joint and grounding box configuration under the target fault type is simulated using the local simulation model. The local simulation results are output. The local simulation results are compared with the voltage and current waveforms tested at the cable joint to verify whether the target fault type is the final type that causes the cable joint sheath to fail, and the fault verification results are obtained.

[0024] This disclosure analyzes the characteristics of abnormal voltage and current in cable joint sheaths in cable lines, identifies multiple possible fault types, and then selects the most likely fault type from the initially determined set of fault types. A simulation model is established, fault scenarios are set, and the characteristics of joint defects and fault conditions are simulated and verified to confirm whether the target fault type is the final type causing the cable joint sheath fault. The fault verification results are obtained, which can handle complex abnormal voltage and current scenarios in cable joint sheaths. It is particularly suitable for the identification and determination of new fault types. By combining data analysis, probability assessment, and simulation verification, it can provide timely and effective support, reduce power system downtime and maintenance costs, and thus solve the technical problem in related technologies where it is impossible to accurately determine the fault type in abnormal voltage and current scenarios in cable joint sheaths. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0026] Figure 1 This is a flowchart of an optional method for determining the fault type of a cable joint sheath according to an embodiment of the present invention;

[0027] Figure 2(a) is a current waveform diagram on the left side of an optional fault connector according to an embodiment of the present invention;

[0028] Figure 2(b) is a current waveform diagram on the right side of an optional fault connector according to an embodiment of the present invention;

[0029] Figure 3(a) is a voltage waveform diagram on the left side of an optional fault connector according to an embodiment of the present invention;

[0030] Figure 3(b) is a voltage waveform diagram on the right side of an optional fault connector according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of current flow analysis for an optional fault connector according to an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of an optional short circuit between grounding wires inside a grounding box according to an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of an optional cross-connection A-phase grounding wire reversal according to an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of an optional insulating partition breakdown according to an embodiment of the present invention;

[0035] Figure 8 This is a schematic diagram of an optional sheath multi-point ground short circuit according to an embodiment of the present invention;

[0036] Figure 9 This is a schematic diagram of an optional cable joint sheath fault type determination device according to an embodiment of the present invention;

[0037] Figure 10 This is a hardware structure block diagram of an electronic device (or mobile device) for determining the fault type of a cable joint sheath according to an embodiment of the present invention. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] To facilitate understanding of the present invention by those skilled in the art, some terms or nouns involved in the various embodiments of the present invention are explained below:

[0041] Alternative Transient Program (ATP) is a professional simulation software for power system transient analysis. It can simulate the behavior of power systems under various fault conditions, and is particularly widely used in high-frequency electromagnetic transient analysis. In this invention, ATP is used to build a simulation model to simulate the voltage and current waveforms of cable joints under specific fault conditions, so as to verify and compare fault characteristics.

[0042] Cross-linked polyethylene (XLPE) is a commonly used insulation material for high-voltage cables. It can withstand high voltages during long-term operation without aging, reducing energy loss during power transmission and improving the service life and safety of the cable.

[0043] Grounding resistance, or R-ground for short, refers to the resistance between the metallic sheath of a cable and the earth. It directly affects the effectiveness of the grounding system. During cable operation, lower grounding resistance helps to quickly discharge fault currents, protecting cables and personnel from overvoltage damage.

[0044] Protective earth (PE) is a safety measure in power systems. By connecting the metal sheath of a cable to the earth, it can quickly guide the fault current to the ground in the event of equipment failure or human contact with live parts, thereby reducing the risk of electric shock and protecting the safety of personnel and equipment.

[0045] Cross-bonded interconnection is a grounding technique used in high-voltage cable systems to balance sheath current and reduce sheath voltage. By cross-interconnecting and grounding the three-phase sheaths at intervals along the cable line, the generation of circulating currents between sheaths can be effectively prevented, the induced voltage on the sheaths can be reduced, and the safety of cable operation can be ensured.

[0046] It should be noted that the fault type determination method and device for cable joint sheaths in this disclosure can be used in the field of cable fault analysis for fault type determination in scenarios of abnormal voltage and current in cable structure sheaths, and can also be used in any field other than the field of cable fault analysis for fault type determination in scenarios of abnormal voltage and current in cable structure sheaths. This disclosure does not limit the application field of the fault type determination method and device for cable joint sheaths.

[0047] It should be noted that the information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, and displayed data) collected in this public disclosure are information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, storage, use, processing, transmission, provision, disclosure, and application of related data all comply with the relevant laws, regulations, and standards of the relevant regions, necessary confidentiality measures have been taken, and they do not violate public order and good morals. Corresponding operation entry points are provided for users to choose to authorize or refuse. For example, this system has interfaces with relevant users or organizations. Before obtaining relevant information, a request to obtain the information needs to be sent to the aforementioned user or organization through the interface, and the relevant information is obtained only after receiving consent from the aforementioned user or organization.

[0048] It should be noted that in this disclosure, customer information is collected and analyzed, and users are provided with corresponding operation entry points to choose whether to agree to or reject the automated decision results; if the user chooses to reject, the process will proceed to the expert decision-making process.

[0049] The following embodiments of the present invention can be applied to systems / applications / equipment for determining fault types in various cable joint sheaths. This invention can be applied to the field of high-voltage cable operation and maintenance technology in power systems, especially for cross-interconnection grounding systems of 110kV and above high-voltage cable lines. In specific application scenarios, this invention can be effectively applied to the monitoring and fault diagnosis of abnormal voltage and current in cable joint sheaths, providing technical support for the safe and stable operation of power systems. When maintenance personnel discover abnormalities in the sheath voltage or current of cable joints during routine inspections or condition monitoring, this invention provides a method for quickly and accurately determining the fault type, avoiding power outages or safety hazards caused by inaccurate fault determination.

[0050] This invention analyzes the abnormal characteristics of cable joint sheath voltage and current, and combines this with simulation verification technology to identify possible types of cable joint sheath faults in a short time. These faults include, but are not limited to, internal short circuits in the grounding box, wiring errors, insulation plate breakdown, and sheath-to-ground short circuits. Based on the sheath voltage and current characteristics, this invention can assess the probability of various fault types, thus providing a basis for maintenance personnel to prioritize high-probability faults.

[0051] By establishing a local simulation model, this invention can simulate cable joint and grounding box configurations under different fault types, compare simulation results with field measurement data, and thus accurately determine the final fault type causing abnormal sheath voltage and current. Accurate fault determination helps to take timely measures to eliminate safety hazards and avoid damage to power equipment or personal injury caused by abnormal sheath voltage and current, thereby enhancing the safety of the entire power system.

[0052] The present invention will now be described in detail with reference to various embodiments.

[0053] Example 1

[0054] According to an embodiment of the present invention, an embodiment of a method for determining the fault type of a cable joint sheath is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0055] Figure 1 This is a flowchart of an optional cable joint sheath fault type determination method according to an embodiment of the present invention, such as... Figure 1 As shown, the method includes the following steps:

[0056] Step S101: Based on the characteristic anomaly analysis results of voltage and current waveforms, a fault type set is obtained. The fault type set includes at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation plate breakdown, and multiple short circuits to ground in the sheath.

[0057] Optionally, the step of obtaining a set of fault types based on the characteristic anomaly analysis results of voltage and current waveforms includes: analyzing the sheath voltage and current waveforms on the left and right sides of the cable joint, identifying patterns in which the current or voltage in at least two phases exhibits abnormal characteristics, and obtaining characteristic anomaly analysis results. The abnormal characteristic patterns include: the presence of low phase-to-phase resistance at the fault joint forming an internal equipotential point, resulting in local current backflow; and based on the characteristic anomaly analysis results, determining the fault types that cause abnormal characteristics in the cable joint sheath, and obtaining a set of fault types.

[0058] In step S101, this embodiment achieves accurate analysis of abnormal sheath voltage and current of cable joints, including detailed comparison and analysis of sheath voltage and current waveforms on the left and right sides of the cable joint. High-precision current and voltage sensors are used to collect and record voltage and current waveform data on both sides of the faulty joint, including current magnitude, direction, frequency, voltage magnitude, direction, and phase.

[0059] Based on the collected voltage and current waveform data, this embodiment uses a data analysis algorithm to identify abnormal characteristic patterns exhibited by at least two phases of current or voltage. These patterns are typically associated with specific fault types at cable joints. For example, if there is a low phase-to-phase resistance forming an internal equipotential point, the algorithm in this embodiment can identify a local current backflow phenomenon, manifested as abnormal phase reversal or in-phase current waveforms on both sides of the cable joint, with an abnormally increased current amplitude, and the voltage waveform also showing an unexpected phase difference or voltage peak consistency.

[0060] After identifying abnormal characteristic patterns, this embodiment determines the fault type that may cause abnormal voltage and current characteristics of the cable joint sheath based on the correlation between these patterns and known fault types. For example, if the currents of phases A and C on the left side of the faulty joint are reversed and the current amplitude is abnormally high, while the current amplitude of phase B is very small, and at the same time, the voltages of phases A and C tend to be in phase, then this embodiment will initially determine that the fault type may be a wiring error, specifically, that the two grounding wires of phase A at the faulty grounding box are reversed.

[0061] Step S102: Determine the target fault type with the highest fault probability from the fault type set.

[0062] Step S102 aims to determine the most likely fault type to cause abnormal voltage and current in the cable joint sheath from among the identified possible fault types, thereby providing a clear direction for subsequent fault analysis and handling. Optionally, step S102 includes: when the fault type is a short circuit between grounding wires inside the grounding box, analyzing whether the current amplitudes on the left and right sides of the short circuit point inside the grounding box are equal, and obtaining a first fault probability based on the first analysis result; or when the fault type is a wiring error, analyzing the short circuit state between the sheaths of the left and right cables of the cable joint, and obtaining a second fault probability based on the second analysis result; or when the fault type is a partition breakdown inside the insulation joint, checking the breakdown probability of the insulation partition of the cable joint sheath, and determining a third fault probability based on the partition breakdown probability value; when the fault type is a simultaneous short circuit between two phase sheaths and ground near the joint, evaluating the probability of multiple short circuits to ground in the sheath, and determining a fourth fault probability; and selecting the fault type corresponding to the highest fault probability as the target fault type.

[0063] When the fault type is a short circuit between grounding wires inside the grounding box, this embodiment analyzes whether the currents on both sides of the short circuit point inside the grounding box exhibit equal amplitude. Based on this analysis, the first fault probability, i.e., the likelihood of a short circuit between grounding wires inside the grounding box, is calculated. When the fault type is a wiring error, this embodiment analyzes whether a short circuit has occurred between the sheaths of the cables on the left and right sides of the cable joint. This embodiment assesses the second fault probability, i.e., the probability of a cable joint sheath fault due to a wiring error, by identifying and comparing the characteristics of these inter-sheath short circuit states.

[0064] When the fault type is that there is a breakdown of the insulating partition inside the cable joint, the insulation partition of the cable joint sheath is checked for breakdown. In this embodiment, the third fault probability is determined based on the probability value of the partition breakdown, that is, the possibility that the insulating partition is broken down. When the fault type is that there is a simultaneous short circuit to ground of two phase sheaths near the joint, the probability of multiple short circuits to ground of the sheaths is evaluated to determine the fourth fault probability, that is, the possibility that a simultaneous short circuit to ground of two phase sheaths occurs near the joint.

[0065] To determine which of the above fault types is the most likely cause of abnormal voltage and current in the cable joint sheath, this embodiment adopts the following logical process: For each fault type, based on the above analysis results, its fault probability is calculated, the probability values ​​of all fault types are compared, and the fault type with the highest probability is selected as the target fault type, thereby accurately identifying the fault type most likely to cause abnormal voltage and current in the cable joint sheath.

[0066] Step S103: Establish a local simulation model, use the local simulation model to simulate the cable joint and grounding box configuration under the target fault type, and output the local simulation results.

[0067] Optionally, the steps of establishing a local simulation model include: constructing a configuration model of cable joints and grounding boxes at the faulty joint and adjacent areas on a simulation software platform to obtain a local simulation model, wherein the local simulation model contains all the key components that cause abnormal voltage and current characteristics.

[0068] It should be noted that the local simulation model was constructed using power system simulation software (a tool for analyzing the electromagnetic transient behavior of power systems). Through detailed modeling, this embodiment can reproduce the cable structure and grounding box configuration at and around the fault joint, forming an accurate local simulation model. The model not only covers the cable joint itself, but also includes the adjacent cable segment and related grounding devices, ensuring that the model can fully reflect the key components that cause abnormal voltage and current characteristics, such as insulating partitions, cable shielding layers, grounding wires, and cable metal sheaths.

[0069] Optionally, the step of outputting local simulation results includes: running a local simulation model, obtaining waveform data of cable joint sheath voltage and current under the target fault type, and outputting local simulation results.

[0070] This embodiment uses a local simulation model to reproduce the target fault type in a virtual environment, simulating the dynamic changes in voltage and current in the cable joint sheath under set fault conditions. Utilizing the computational capabilities of the simulation software, the model can generate detailed waveform data, visually displaying the characteristics of voltage and current under fault conditions, including frequency, phase, amplitude, and waveform shape and periodicity. The output local simulation results form the basis for subsequent analysis and verification, helping maintenance personnel gain a deeper understanding of the specific manifestations of the fault and providing important reference for interpreting field test data.

[0071] Step S104: Compare the local simulation results with the voltage and current waveforms measured at the cable joint to verify whether the target fault type is the final type that causes the cable joint sheath to fail, and obtain the fault verification result.

[0072] Optionally, the step of comparing the local simulation results with the voltage and current waveforms tested at the cable joint includes: comparing the voltage and current waveforms in the local simulation results with the voltage and current waveforms obtained from the field test at the cable joint point by point to determine the similarity between the two waveforms.

[0073] Optionally, the step of obtaining the fault verification result includes: if the matching degree between the local simulation result and the tested voltage and current waveform is higher than a preset matching degree threshold, confirming that the target fault type is the final type that leads to the cable joint sheath fault.

[0074] In this embodiment, the local simulation results are compared and analyzed with the voltage and current waveforms in the field test data of the cable joint to verify whether the previously determined target fault type is indeed the direct cause of the abnormality of the cable joint sheath, thereby obtaining the fault verification results.

[0075] It should be noted that when comparing waveforms, this embodiment adopts a point-by-point comparison method, that is, matching and comparing the voltage and current values ​​at a specific time point obtained from simulation with the voltage and current values ​​at the same time point obtained from field testing one by one. This can evaluate the similarity between the two waveforms in detail, including key parameters such as waveform shape, frequency, and amplitude, to ensure the accuracy and reliability of the comparison results.

[0076] This embodiment employs similarity measurement algorithms (such as correlation coefficient, Euclidean distance, Dynamic Time Warping (DTW), or signal processing methods) to calculate the similarity index between two waveforms. If the calculated matching degree is higher than a preset matching degree threshold, it means that the simulation result is highly consistent with the field test data, thus the target fault type can be identified as the final fault type; otherwise, the fault type needs to be re-evaluated or the simulation model settings need to be checked. The determination process not only verifies the accuracy of the fault type but also provides a clear direction for subsequent fault handling, helping to quickly take targeted measures to restore the normal operation of the cable system.

[0077] Through the above steps, a set of fault types can be obtained based on the anomaly analysis results of voltage and current waveforms. The fault types in the set include at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation plate breakdown, and multiple short circuits to ground in the sheath. The target fault type with the highest probability is determined from the set of fault types. A local simulation model is established to simulate the cable joint and grounding box configuration under the target fault type, and the local simulation results are output. The local simulation results are compared with the voltage and current waveforms tested at the cable joint to verify whether the target fault type is the final type that causes the cable joint sheath to fail, and the fault verification results are obtained. In this embodiment, the characteristics of abnormal voltage and current in cable joint sheaths can be analyzed to determine multiple possible fault types. Then, the most likely fault type is selected from the initially determined fault type set, a simulation model is established, fault scenarios are set, and the joint defect characteristics and fault conditions are simulated and verified to verify whether the target fault type is the final type causing the cable joint sheath fault. The fault verification result is obtained, which can cope with complex abnormal voltage and current scenarios in cable joint sheaths. It is particularly suitable for the identification and determination of new fault types. By combining data analysis, probability assessment and simulation verification, it can provide timely and effective support, reduce power system downtime and maintenance costs, and thus solve the technical problem in related technologies that it is impossible to accurately determine the fault type in abnormal voltage and current scenarios in cable joint sheaths.

[0078] The following describes in detail another optional implementation method.

[0079] Step 1: Analysis of the voltage and current characteristics of the cable joint sheath.

[0080] Figure 2(a) is a current waveform diagram on the left side of an optional fault connector according to an embodiment of the present invention;

[0081] Figure 2(b) is a current waveform diagram on the right side of an optional fault connector according to an embodiment of the present invention;

[0082] Figure 3(a) is a voltage waveform diagram on the left side of an optional fault connector according to an embodiment of the present invention;

[0083] Figure 3(b) is a voltage waveform diagram on the right side of an optional fault connector according to an embodiment of the present invention.

[0084] Through analysis Figure 2(a)-Figure 2(b) A schematic diagram of the current waveform of a faulty cable joint and Figures 3(a)-3(b) The illustrated voltage waveform diagrams provide comparisons for phases A, B, C, direct grounding, and the main cable. Phase A is indicated by yellow, phase B by green, phase C by red, and direct grounding by blue. These five scenarios are explained above each diagram. The last scenario, the main cable, is hidden in gray as it is not required to be displayed. It can be seen that on the left, the sheath currents of phases A and C are in opposite phases, with the amplitudes of phases A and C being nearly equal and much larger than that of phase B, while the amplitude of phase B is very small. On the right, the sheath circulating currents of phases A and B are in opposite phases, with the amplitudes of phases A and B being nearly equal and much larger than that of phase C, while the amplitude of phase C is very small. From the voltage phase difference and waveform diagrams, it can be seen that the sheath voltages of phases A and C on the left side of the faulty connector tend to be in phase and their waveforms overlap, as do the voltages of phases A and B on the right side of the faulty connector. This indicates that the potentials of phases A and C on the left side of the faulty connector are the same, which is an equipotential point, and the potential difference between these two phases is close to 0; the potentials of phases A and B on the right side of the faulty connector are the same, which is an equipotential point, and the potential difference between these two phases is close to 0.

[0085] Step 2: Analysis of joint defect characteristics and the probability of failure.

[0086] Based on the combined voltage and current characteristics of the sheaths on both sides of the faulty connector, it was initially determined that there was a low phase-to-phase resistance at the faulty connector, which formed an internal equipotential point (such as a short circuit between phases A and C on the left side of the faulty connector; a short circuit between phases A and B on the right side of the faulty connector, etc.). This resulted in insufficient cross-connection commutation and the formation of local backflow. Figure 4 This is a schematic diagram of current flow analysis for an optional faulty connector according to an embodiment of the present invention, as shown below. Figure 4 As shown, I1 and I2 are the currents in the two circuits on both sides of the faulty connector.

[0087] The reasons for the presence of equipotential points in the sheath between the two phases at the joint include:

[0088] 1) Short circuit between grounding wires inside the grounding box.

[0089] 2) The grounding wire at the joint is connected incorrectly.

[0090] 3) There is a breakdown of the internal partition in the insulating joint;

[0091] 4) There is a simultaneous short circuit to ground in the sheath of two phases near the joint.

[0092] A detailed analysis will now be conducted for different situations:

[0093] Step 3: Precise analysis of joint defect characteristics and fault conditions.

[0094] 1) Short circuit between grounding wires inside the grounding box.

[0095] Figure 5 This is a schematic diagram of an optional short circuit between grounding wires inside a grounding box according to an embodiment of the present invention, as shown below. Figure 5 As shown, if the short circuit point is inside the grounding box, the currents on both sides of the short circuit point are equal in magnitude but opposite in phase. Since different loops are formed on either side of the short circuit point, the current amplitudes on both sides are unequal. However, the fully sealed cable sheath direct grounding box is suitable for direct grounding connections of the metal sheath of three-phase single-circuit high-voltage cables. It consists of an integral insulating load-bearing frame, a one-piece molded dense EPDM rubber waterproof layer, and a stainless steel protective layer. The box has excellent sealing performance, and there is no short circuit inside the box.

[0096] 2) The grounding wire of phase A at the faulty connector is reversed.

[0097] Figure 6 This is a schematic diagram of an optional cross-connection A-phase grounding wire reversal according to an embodiment of the present invention, as shown below. Figure 6 As shown, if the two grounding wires of phase A are reversed, according to the commutation relationship of the grounding box, a short circuit will occur between the sheaths of phases A and C of the cable on the left side of the faulty connector, and between the sheaths of phases A and B of the cable on the right side of the faulty connector. Therefore, a loop is formed between the sheaths of phases A and C of the faulty connector on the right side of connector #3, and an incomplete commutation loop is also formed between the sheaths of the faulty connector on the right side of connector and the terminal of the front gate station. The current in both loops is greater than the circulating current during normal commutation.

[0098] 3) There is a breakdown of the internal partition of the insulating joint.

[0099] Figure 7 This is a schematic diagram of an optional insulating partition breakdown according to an embodiment of the present invention, as shown below. Figure 7 As shown, assuming the insulation partition of the cross-connected B-phase joint breaks down, the sheath current amplitude of the incoming and outgoing lines at the B-phase joint would be equal and the direction of flow would be the same. However, the current amplitude on both sides of the joint horn of each phase of the faulty joint is different and the difference is large, thus ruling out the possibility of insulation partition breakdown.

[0100] 4) There is a simultaneous short circuit to ground in the sheath of two phases near the joint.

[0101] Figure 8 This is a schematic diagram of an optional sheath multi-point ground short circuit according to an embodiment of the present invention, as shown below. Figure 8As shown, assuming that both phase A and phase C sheaths are simultaneously short-circuited to ground on the left side of the cross-connected fault junction, the current flows on both sides of the short circuit would be I1 and I2, respectively. Therefore, the data measured at the fault junction exhibit the following characteristics: the amplitudes of phases A and C on the left side of the fault are equal and opposite in direction; the amplitudes of phases A and B on the right side of the fault are equal and opposite in direction; and the amplitudes of these four measurements are equal. Similarly, it can be deduced that if two phases are simultaneously short-circuited to ground on the right side of the fault junction, the measured values ​​will also exhibit the above characteristics. However, the current values ​​measured at the grounding box of the fault junction are not equal on both sides, thus ruling out the possibility of two phases being simultaneously short-circuited to ground.

[0102] Based on the above analysis, the defect is preliminarily located at the faulty grounding box. Possible causes include:

[0103] The two grounding wires of phase A at the fault grounding box are reversed.

[0104] Since the cross-connection grounding box has high stability, there is generally no two-phase short circuit in the cross-connection box. Therefore, it is speculated that the cause of the fault is most likely that the two grounding wires of phase A at the faulty grounding box are reversed.

[0105] Step 4: Simulation verification of joint defect characteristics and fault conditions.

[0106] A simulation model of the reversed grounding wire of phase A at the faulty joint was built on the ATP simulation software platform, and the sheath current was calculated. The simulation results show that the fault characteristics of the cross-connection external wiring error simulation are the same as the field measurement results. Therefore, the joint fault is that the grounding wire of a certain phase is reversed.

[0107] Through the above implementation methods, this paper addresses a scenario of abnormal voltage and current in the cable joint sheath that occurs during actual operation and maintenance of cable lines. Based on the analysis of its voltage and current characteristics, various possible faults are proposed. A detailed analysis of the voltage and current characteristics of the cable joint sheath under various fault conditions is conducted to determine the most likely fault. Finally, a simulation model is established, fault scenarios are set, and the characteristics of joint defects and fault conditions are simulated and verified.

[0108] The embodiments of the present invention can analyze the sheath voltage and current characteristics when two grounding wires of a certain phase are reversed at the cable grounding box, which facilitates the fault diagnosis when the sheath voltage and current scenario of this joint occurs in actual operation and maintenance.

[0109] The following is a detailed description with reference to another embodiment.

[0110] Example 2

[0111] The fault type determination device for cable joint sheath provided in this embodiment includes multiple implementation units, each of which corresponds to a specific implementation step in Embodiment 1 above.

[0112] Figure 9 This is a schematic diagram of an optional cable joint sheath fault type determination device according to an embodiment of the present invention, as shown below. Figure 9 As shown, the fault type determination device for the cable joint sheath may include: a fault type analysis unit 91, a fault type determination unit 92, a simulation unit 93, and a fault determination unit 94.

[0113] The fault type analysis unit 91 is used to obtain a fault type set based on the characteristic anomaly analysis results of voltage and current waveforms. The fault type in the fault type set includes at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation plate breakdown, and multiple short circuits to ground in the sheath.

[0114] The fault type determination unit 92 is used to determine the target fault type with the highest fault probability from the fault type set.

[0115] Simulation unit 93 is used to establish a local simulation model, which simulates the cable joint and grounding box configuration under the target fault type and outputs the local simulation results.

[0116] The fault determination unit 94 is used to compare the local simulation results with the voltage and current waveforms tested at the cable joint to verify whether the target fault type is the final type that causes the cable joint sheath to fail, and to obtain the fault verification result.

[0117] The aforementioned fault type determination device for cable joint sheaths can obtain a set of fault types based on the characteristic anomaly analysis results of voltage and current waveforms through the fault type analysis unit 91. The fault types in the fault type set include at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation plate breakdown, and multiple short circuits to ground in the sheath. The fault type determination unit 92 determines the target fault type with the highest probability from the fault type set. The simulation unit 93 establishes a local simulation model and uses the local simulation model to simulate the cable joint and grounding box configuration under the target fault type, outputting the local simulation results. The fault determination unit 94 compares the local simulation results with the voltage and current waveforms tested at the cable joint to verify whether the target fault type is the final type causing the cable joint sheath to fail, thus obtaining the fault verification result. In this embodiment, the characteristics of abnormal voltage and current in cable joint sheaths can be analyzed to determine multiple possible fault types. Then, the most likely fault type is selected from the initially determined fault type set, a simulation model is established, fault scenarios are set, and the joint defect characteristics and fault conditions are simulated and verified to verify whether the target fault type is the final type causing the cable joint sheath fault. The fault verification result is obtained, which can cope with complex abnormal voltage and current scenarios in cable joint sheaths. It is particularly suitable for the identification and determination of new fault types. By combining data analysis, probability assessment and simulation verification, it can provide timely and effective support, reduce power system downtime and maintenance costs, and thus solve the technical problem in related technologies that it is impossible to accurately determine the fault type in abnormal voltage and current scenarios in cable joint sheaths.

[0118] Optionally, the fault type analysis unit includes: a current and voltage analysis module, used to analyze the sheath voltage and current waveforms on the left and right sides of the cable joint, identify patterns in which the current or voltage in at least two phases exhibits abnormal characteristics, and obtain characteristic anomaly analysis results, wherein the abnormal characteristic patterns include: the presence of low phase-to-phase resistance at the fault joint forming an internal equipotential point, resulting in local current backflow; and a fault type determination module, used to determine the fault type causing the abnormal characteristics of the cable joint sheath based on the characteristic anomaly analysis results, and obtain a fault type set.

[0119] Optionally, the fault type determination unit includes: a first fault probability analysis module, used to analyze whether the current amplitudes on the left and right sides of the short circuit point inside the grounding box are equal when the fault type is a short circuit between grounding wires inside the grounding box, and obtain a first fault probability based on the first analysis result; a second fault probability analysis module, used to analyze the short circuit state between the sheaths of the left and right cables of the cable joint when the fault type is a wiring error, and obtain a second fault probability based on the second analysis result; a third fault probability analysis module, used to check the breakdown probability of the insulating partition of the cable joint sheath when the fault type is a partition breakdown inside the insulating joint, and determine a third fault probability based on the partition breakdown probability value; a fourth fault probability analysis module, used to evaluate the probability of multiple short circuits to ground of the sheath when the fault type is a simultaneous short circuit between two phase sheaths and ground near the joint, and determine a fourth fault probability; and a fault type selection module, used to select the fault type corresponding to the highest fault probability as the target fault type.

[0120] Optionally, the simulation unit includes a model building module, used to build a configuration model of cable joints and grounding boxes at the faulty joint and adjacent areas on the simulation software platform to obtain a local simulation model, wherein the local simulation model contains all the key components that cause abnormal voltage and current characteristics.

[0121] Optionally, the simulation unit also includes a model running module, which is used to run a local simulation model, acquire waveform data of cable joint sheath voltage and current under the target fault type, and output local simulation results.

[0122] Optionally, the fault determination unit includes a voltage and current comparison module, which is used to compare the voltage and current waveforms in the local simulation results with the voltage and current waveforms obtained from the on-site test of the cable joint point by point to determine the similarity between the two waveforms.

[0123] Optionally, when the fault determination unit obtains the fault verification result, it includes: a fault type determination module, used to confirm that the target fault type is the final type that leads to the cable joint sheath fault when the matching degree between the local simulation result and the tested voltage and current waveform is higher than a preset matching degree threshold.

[0124] The fault type determination device for the cable joint sheath may also include a processor and a memory. The fault type analysis unit 91, fault type determination unit 92, simulation unit 93, fault determination unit 94, etc. are all stored in the memory as program units, and the processor executes the program units stored in the memory to realize the corresponding functions.

[0125] The aforementioned processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and the comparison results can be sent to the target terminal by adjusting the kernel parameters.

[0126] The aforementioned memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0127] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored computer program, wherein, when the computer program is running, it controls the device where the computer-readable storage medium is located to execute the cable joint sheath fault type determination method of any one of the above embodiments.

[0128] According to another aspect of the present invention, an electronic device is also provided, including one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the cable joint sheath fault type determination method of any one of the above embodiments.

[0129] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the fault type determination method for the cable joint sheath described in various embodiments of this application.

[0130] This application also provides a computer program product, including a non-volatile computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the cable joint sheath fault type determination method described in various embodiments of this application.

[0131] Figure 10 This is a hardware structure block diagram of an electronic device (or mobile device) for a fault type determination method for cable joint sheaths according to an embodiment of the present invention. Figure 10 As shown, an electronic device may include one or more ( Figure 10 The processor (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and memory 1004 for storing data are illustrated using 1002a, 1002b, ..., 1002n. In addition, it may include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, a keyboard, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 10 The structure shown is for illustrative purposes only and does not limit the structure of the electronic device described above. For example, the electronic device may also include components that are more... Figure 10The more or fewer components shown, or having the same Figure 10 The different configurations shown.

[0132] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0133] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0134] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0135] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0136] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0137] If the integrated unit 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, in essence, or the part that contributes to the prior art, or all or 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, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0138] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the fault type of a cable joint sheath, characterized in that, include: Based on the characteristic anomaly analysis results of voltage and current waveforms, a set of fault types is obtained, wherein the fault types in the set of fault types include at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation partition breakdown, and multiple short circuits to ground in the sheath. Determine the target fault type with the highest fault probability from the set of fault types; A local simulation model is established, and the cable joint and grounding box configurations under the target fault type are simulated using the local simulation model. The local simulation results are then output. By comparing the local simulation results with the voltage and current waveforms measured at the cable joint, it is verified whether the target fault type is the final type that causes the cable joint sheath to fail, and the fault verification result is obtained.

2. The fault type determination method according to claim 1, characterized in that, The steps for obtaining a set of fault types based on the characteristic anomaly analysis results of voltage and current waveforms include: Analyze the sheath voltage and current waveforms on the left and right sides of the cable joint to identify patterns in which the current or voltage in at least two phases exhibits abnormal characteristics, and obtain the abnormal characteristic analysis results. The abnormal characteristic patterns include: the presence of low phase-to-phase resistance at the faulty joint to form an internal equipotential point, resulting in local current backflow. Based on the results of the anomaly analysis, the fault types that cause abnormal characteristics in the cable joint sheath are determined, and the set of fault types is obtained.

3. The fault type determination method according to claim 1, characterized in that, The step of determining the target fault type with the highest fault probability from the set of fault types includes: When the fault type is a short circuit between grounding wires inside the grounding box, analyze whether the current amplitudes on both sides of the short circuit point inside the grounding box are equal, and obtain the first fault probability based on the first analysis result; or, When the fault type is wiring error, analyze the short-circuit state between the sheaths of the cables on the left and right sides of the cable joint, and obtain the second fault probability based on the second analysis results; or, When the fault type is that there is a diaphragm breakdown inside the insulation joint, check the breakdown probability of the insulation diaphragm of the cable joint sheath, and determine the third fault probability based on the diaphragm breakdown probability value. When the fault type is that there is a simultaneous short circuit to ground of two phase sheaths near the joint, assess the probability of multiple short circuits to ground of the sheaths and determine the probability of the fourth fault. The fault type with the highest failure probability is selected as the target fault type.

4. The fault type determination method according to claim 1, characterized in that, The steps to establish a local simulation model include: A configuration model of cable joints and grounding boxes at the faulty joint and adjacent areas is constructed on a simulation software platform to obtain the local simulation model, wherein the local simulation model contains all the key components that cause abnormal voltage and current characteristics.

5. The fault type determination method according to claim 1, characterized in that, The steps for outputting local simulation results include: Run the local simulation model to obtain waveform data of cable joint sheath voltage and current under the target fault type, and output the local simulation results.

6. The fault type determination method according to claim 1, characterized in that, The step of comparing the local simulation results with the voltage and current waveforms measured at the cable joint includes: The voltage and current waveforms in the local simulation results are compared point by point with the voltage and current waveforms obtained from the on-site test of the cable joint to determine the similarity between the two waveforms.

7. The fault type determination method according to claim 1, characterized in that, The steps to obtain fault verification results include: If the matching degree between the local simulation results and the tested voltage and current waveforms is higher than a preset matching degree threshold, the target fault type is confirmed as the final type leading to cable joint sheath failure.

8. A fault type determination device for cable joint sheaths, characterized in that, include: The fault type analysis unit is used to obtain a fault type set based on the characteristic anomaly analysis results of voltage and current waveforms. The fault type set includes at least one of the following: short circuit between grounding wires inside the grounding box, wiring error, insulation partition breakdown, and multiple short circuits to ground in the sheath. A fault type determination unit is used to determine the target fault type with the highest fault probability from the set of fault types; The simulation unit is used to establish a local simulation model, simulate the cable joint and grounding box configuration under the target fault type using the local simulation model, and output the local simulation results. The fault determination unit is used to compare the local simulation results with the voltage and current waveforms tested at the cable joint, verify whether the target fault type is the final type that causes the cable joint sheath to fail, and obtain the fault verification result.

9. An electronic device, characterized in that, It includes one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the fault type determination method for cable joint sheaths according to any one of claims 1 to 7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the fault type determination method for the cable joint sheath as described in any one of claims 1 to 7.

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