Segmented aging monitoring system and method for direct-current submarine cable

Abstract

The invention discloses a segmented aging monitoring system and method for a direct-current submarine cable, and belongs to the technical field of submarine cable aging monitoring. The system comprises a first sensor, a second sensor and a PC end analysis platform; the first sensor is embedded between the insulating layer and the alloy lead sleeve of each submarine cable section and is used for monitoring the temperature data of the insulating layer of the submarine cable section in real time; the second sensor is connected with the ground wire on each submarine cable section and is used for monitoring leakage current data of the submarine cable sections in real time; wherein the direct current submarine cable to be measured is divided according to a preset segmentation distance to obtain submarine cable sections; and the PC end analysis platform is used for calculating the aging degree of the submarine cable section according to the insulating layer temperature data and the leakage current data. By implementing the method and the device, the problems of difficulty in accurately positioning an actual aged part, difficulty in overhauling and high cost caused by aging evaluation of the whole submarine cable due to direct acquisition of monitoring data of the whole submarine cable in the prior art can be solved.

Description

Technical Field

[0001] This invention relates to the field of submarine cable aging monitoring technology, and in particular to a segmented aging monitoring system and method for DC submarine cables. Background Technology

[0002] As the core carrier of cross-sea power transmission, submarine DC cables operate for extended periods in complex marine environments characterized by high voltage DC (e.g., ±320kV~±525kV), high humidity, and high salt corrosion. Their insulation layers (e.g., cross-linked polyethylene XLPE) are prone to water treeing and electrical treeing degradation under the combined effects of electro-thermal-mechanical stress, leading to a decrease in insulation resistance and a continuous increase in leakage current. Therefore, aging monitoring and evaluation are crucial.

[0003] Current monitoring methods for DC submarine cables mostly involve directly collecting monitoring data from the entire cable to obtain an aging assessment result. However, since DC submarine cables are primarily used for long-distance power transmission, they are quite long. Under current methods, because the aging assessment result is for the entire cable, it is difficult to accurately locate the actual aging areas, leading to difficulties in maintenance and high costs. Summary of the Invention

[0004] This invention provides a segmented aging monitoring system and method for DC submarine cables, which can solve the problems in the prior art where the monitoring data of the entire submarine cable is directly collected to assess the aging of the entire cable, making it difficult to accurately locate the actual aging parts, resulting in difficult maintenance and high costs.

[0005] An embodiment of the present invention provides a segmented aging monitoring system for DC submarine cables, comprising:

[0006] First sensor, second sensor, and PC-based analysis platform;

[0007] The first sensor is embedded between the insulation layer and the alloy lead sheath of each submarine cable segment along the length of the DC submarine cable to be tested. The second sensor is deployed on the outer surface of each submarine cable segment and connected to the ground wire of the corresponding submarine cable segment. The submarine cable segments are obtained by dividing the DC submarine cable to be tested according to a preset segmentation distance.

[0008] The aforementioned first sensor is used to monitor the insulation temperature data of the corresponding submarine cable segment in real time and transmit the insulation temperature data to the aforementioned PC-based analysis platform.

[0009] The aforementioned second sensor is used to monitor the leakage current data of the corresponding submarine cable segment in real time and transmit the leakage current data to the aforementioned PC-based analysis platform.

[0010] The aforementioned PC-based analysis platform is used to calculate the aging degree of the corresponding submarine cable segment based on the insulation layer temperature data and leakage current data.

[0011] Furthermore, based on the aforementioned insulation temperature data and leakage current data, the aging degree of the corresponding submarine cable segment was calculated, including:

[0012] Based on the above insulation temperature data, the average temperature and temperature rise slope of the corresponding submarine cable section were calculated.

[0013] Based on the above leakage current data, the average leakage current of the corresponding submarine cable section was calculated.

[0014] Based on the above average temperature, temperature rise slope, and average leakage current, the aging degree of the corresponding submarine cable section is calculated.

[0015] Furthermore, the aforementioned PC-based analytics platform is also used for:

[0016] Obtain the first degree of aging corresponding to a healthy submarine cable segment, and the second degree of aging corresponding to a submarine cable segment that is on the verge of breakdown;

[0017] For each segment of the aforementioned DC submarine cable under test, the aging level of each segment is assessed based on the aforementioned aging degree, the aforementioned first aging degree, and the aforementioned second aging degree. If the aforementioned aging level exceeds the preset aging level threshold, an early warning is issued for the corresponding submarine cable segment.

[0018] Furthermore, it also includes: a signal relay processing unit and a cloud server;

[0019] The aforementioned signal relay processing unit is communicatively connected to the aforementioned first sensor, second sensor, and cloud server, respectively.

[0020] The aforementioned signal relay processing unit is used to receive insulation layer temperature data and leakage current data emitted by the aforementioned first sensor and second sensor, and to send the insulation layer temperature data and leakage current data to the aforementioned cloud server.

[0021] The aforementioned cloud server is used to store the insulation layer temperature data and leakage current data after receiving them, and simultaneously send them to the aforementioned PC-based analysis platform.

[0022] Furthermore, the aforementioned signal relay processing unit also includes:

[0023] It integrates an optical signal demodulation module, a current signal acquisition module, and a microprocessor;

[0024] The aforementioned integrated optical signal demodulation module is used to receive the insulation layer temperature data emitted by the aforementioned first sensor and send the insulation layer temperature data to the aforementioned microprocessor;

[0025] The aforementioned current signal acquisition module is used to receive leakage current data emitted by the aforementioned first sensor and send the leakage current data to the aforementioned microprocessor;

[0026] The aforementioned microprocessor is used to convert the aforementioned insulation layer temperature data and leakage current data from analog to digital and then send them to the aforementioned cloud server.

[0027] Furthermore, the aforementioned first sensor is specifically a distributed optical fiber sensor.

[0028] Furthermore, the aforementioned second sensor is specifically a fluxgate sensor.

[0029] Based on the above-mentioned device embodiments, the present invention provides a segmented aging monitoring method for DC submarine cables, applicable to the PC-side analysis platform in the segmented aging monitoring system for DC submarine cables described in any of the above embodiments.

[0030] The above monitoring methods include:

[0031] The insulation temperature data and leakage current data of each segment of the DC submarine cable under test are acquired; wherein the insulation temperature data and leakage current data are obtained by the first sensor and the second sensor respectively, and transmitted to the PC-based analysis platform; the submarine cable segments are obtained by dividing the DC submarine cable under test according to a preset segmentation distance.

[0032] Based on the above insulation temperature data and leakage current data, the aging degree of the corresponding submarine cable section was calculated.

[0033] Furthermore, based on the aforementioned insulation temperature data and leakage current data, the aging degree of the corresponding submarine cable segment was calculated, including:

[0034] Based on the above insulation temperature data, the average temperature and temperature rise slope of the corresponding submarine cable section were calculated.

[0035] Based on the above leakage current data, the average leakage current of the corresponding submarine cable section was calculated.

[0036] Based on the above average temperature, temperature rise slope, and average leakage current, the aging degree of the corresponding submarine cable section is calculated.

[0037] Furthermore, after obtaining the aging degree of each submarine cable segment, it also includes:

[0038] Obtain the first degree of aging corresponding to a healthy submarine cable segment, and the second degree of aging corresponding to a submarine cable segment that is on the verge of breakdown;

[0039] For each segment of the aforementioned DC submarine cable under test, the aging level of each segment is assessed based on the aforementioned aging degree, the aforementioned first aging degree, and the aforementioned second aging degree. If the aforementioned aging level exceeds the preset aging level threshold, an early warning is issued for the corresponding submarine cable segment.

[0040] The embodiments of the present invention have the following beneficial effects:

[0041] This invention provides a segmented aging monitoring system and method for DC submarine cables. The system includes: a first sensor, a second sensor, and a PC-based analysis platform. The first sensor is embedded between the insulation layer and the lead alloy sheath of each segment of the DC submarine cable along its length. The second sensor is disposed on the outer surface of each segment and connected to the ground wire of the corresponding segment. The cable segments are obtained by dividing the DC submarine cable under test into segments at preset intervals. The first sensor is used to monitor the insulation layer temperature data of the corresponding segment in real time and transmit the insulation layer temperature data to the PC-based analysis platform. The second sensor is used to monitor the leakage current data of the corresponding segment in real time and transmit the leakage current data to the PC-based analysis platform. The PC-based analysis platform is used to calculate the aging degree of the corresponding segment based on the insulation layer temperature data and the leakage current data. Therefore, this invention divides the entire DC submarine cable under test into segments, and then deploys sensors in each segment to monitor insulation temperature and leakage current data. Thus, on the PC-based analysis platform, aging monitoring can be performed on each segment one by one. Since the data corresponds one-to-one with the cable segment, the aging location of the DC submarine cable can be determined, and then the segment can be directly repaired instead of the entire DC submarine cable, greatly reducing maintenance costs. Attached Figure Description

[0042] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the structure of a segmented aging monitoring system for a DC submarine cable provided in an embodiment of the present invention.

[0044] Figure 2 This is a schematic diagram of the sensor placement according to an embodiment of the present invention.

[0045] Figure 3 This is a flowchart illustrating a segmented aging monitoring method for DC submarine cables according to an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0048] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0049] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0050] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0051] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0052] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0053] See Figure 1 To address the problems in existing technologies where monitoring data from the entire submarine cable is directly collected for aging assessment, making it difficult to accurately pinpoint the actual aging areas and resulting in challenging and costly maintenance, this invention provides a segmented aging monitoring system for DC submarine cables, comprising:

[0054] First sensor, second sensor, and PC-based analysis platform;

[0055] The first sensor is embedded between the insulation layer and the alloy lead sheath of each submarine cable segment along the length of the DC submarine cable to be tested. The second sensor is deployed on the outer surface of each submarine cable segment and connected to the ground wire of the corresponding submarine cable segment. The submarine cable segments are obtained by dividing the DC submarine cable to be tested according to a preset segmentation distance.

[0056] The aforementioned first sensor is used to monitor the insulation temperature data of the corresponding submarine cable segment in real time and transmit the insulation temperature data to the aforementioned PC-based analysis platform.

[0057] The aforementioned second sensor is used to monitor the leakage current data of the corresponding submarine cable segment in real time and transmit the leakage current data to the aforementioned PC-based analysis platform.

[0058] The aforementioned PC-based analysis platform is used to calculate the aging degree of the corresponding submarine cable segment based on the insulation layer temperature data and leakage current data.

[0059] Indicative Figure 1 The “segmented submarine cable” refers to the aforementioned submarine cable segment, the “embedded optical fiber” refers to the aforementioned first sensor, and the “magnetic fluxgate sensor array” refers to the aforementioned second sensor. The second sensor is deployed on the outer surface of the submarine cable and can be protected and fixed using a protective shell.

[0060] An illustrative diagram showing the sensor placement locations is shown below. Figure 2As shown, inside the DC submarine cable, from the outside in, there are an armor layer, a PE outer sheath, an alloy lead sheath, an insulation layer, and a conductor. The first sensor is embedded between the insulation layer and the alloy sheath, ensuring close contact with the DC submarine cable body under test. Subsequently, the ground wire of the DC submarine cable under test is embedded in the reserved slot of the protective shell of the second sensor, so that the second sensor can monitor the leakage current data flowing through the ground wire of the corresponding cable segment.

[0061] Preferably, multiple second sensors can be deployed at preset distances along the same submarine cable segment.

[0062] In this preferred embodiment, by deploying sensors in segments to monitor the insulation temperature and leakage current data of each submarine cable segment, the aging degree of each submarine cable segment can be calculated one by one.

[0063] In another preferred embodiment, the calculation of the aging degree of the corresponding submarine cable segment based on the insulation layer temperature data and leakage current data includes:

[0064] Based on the above insulation temperature data, the average temperature and temperature rise slope of the corresponding submarine cable section were calculated.

[0065] Based on the above leakage current data, the average leakage current of the corresponding submarine cable section was calculated.

[0066] Based on the above average temperature, temperature rise slope, and average leakage current, the aging degree of the corresponding submarine cable section is calculated.

[0067] Specifically, after calculating the aging degree of the corresponding submarine cable segment based on average temperature, temperature rise slope, and average leakage current, the aging degree value is output segment by segment. The aging degree is calculated according to the following formula:

[0068]

[0069] In the formula, D(t) represents the degree of aging at time t, k1 represents the weight corresponding to the average leakage current, and I leak The average leakage current is represented by n and m, the material coefficients are represented by k2, and the weight corresponding to the average temperature is represented by E. a k represents the activation energy. B K represents the Boltzmann constant, and k3 represents the weight corresponding to the temperature rise slope. This indicates the temperature rise slope, and T represents the insulation layer temperature data. avg This indicates the average temperature.

[0070] In this preferred embodiment, the aging degree of each submarine cable segment is calculated by calculating the average temperature, temperature rise slope, and average leakage current of each segment.

[0071] In another preferred embodiment, the PC-based analysis platform described above is also used for:

[0072] Obtain the first degree of aging corresponding to a healthy submarine cable segment, and the second degree of aging corresponding to a submarine cable segment that is on the verge of breakdown;

[0073] For each segment of the aforementioned DC submarine cable under test, the aging level of each segment is assessed based on the aforementioned aging degree, the aforementioned first aging degree, and the aforementioned second aging degree. If the aforementioned aging level exceeds the preset aging level threshold, an early warning is issued for the corresponding submarine cable segment.

[0074] Specifically, the first degree of aging is calculated based on the healthy model of the submarine cable, and the second degree of aging is calculated based on the model of the submarine cable nearing breakdown. This allows for the classification of aging levels. Then, the aging level of each segment of the DC submarine cable under test is compared with the threshold range corresponding to each level to determine the aging level of each segment.

[0075] Preferably, after obtaining the aging level of each submarine cable segment, the aging assessment report for each segment is generated based on a multi-source data fusion algorithm.

[0076] In this preferred embodiment, the aging level of each submarine cable segment was assessed by using a first aging level based on a healthy submarine cable and a second aging level corresponding to a submarine cable on the verge of breakdown, and an aging warning was issued based on the assessment results.

[0077] In another preferred embodiment, it further includes: a signal relay processing unit and a cloud server;

[0078] The aforementioned signal relay processing unit is communicatively connected to the aforementioned first sensor, second sensor, and cloud server, respectively.

[0079] The aforementioned signal relay processing unit is used to receive insulation layer temperature data and leakage current data emitted by the aforementioned first sensor and second sensor, and to send the insulation layer temperature data and leakage current data to the aforementioned cloud server.

[0080] The aforementioned cloud server is used to store the insulation layer temperature data and leakage current data after receiving them, and simultaneously send them to the aforementioned PC-based analysis platform.

[0081] Specifically, the signal relay processing unit receives insulation temperature data and leakage current data, forwards them to a cloud server for storage, and then sends them from the cloud server to a PC-based analysis platform for data processing. Illustratively, each submarine cable segment corresponds to one signal relay processing unit.

[0082] In this preferred embodiment, the segmented aging monitoring system for DC submarine cables also includes a signal relay processing unit and a cloud server for data transmission and storage.

[0083] In another preferred embodiment, the signal relay processing unit further includes:

[0084] It integrates an optical signal demodulation module, a current signal acquisition module, and a microprocessor;

[0085] The aforementioned integrated optical signal demodulation module is used to receive the insulation layer temperature data emitted by the aforementioned first sensor and send the insulation layer temperature data to the aforementioned microprocessor;

[0086] The aforementioned current signal acquisition module is used to receive leakage current data emitted by the aforementioned first sensor and send the leakage current data to the aforementioned microprocessor;

[0087] The aforementioned microprocessor is used to convert the aforementioned insulation layer temperature data and leakage current data from analog to digital and then send them to the aforementioned cloud server.

[0088] Specifically, the signal relay processing unit also includes an integrated optical signal demodulation module, a current signal acquisition module, and a microprocessor. The integrated optical signal demodulation module is used to acquire the insulation layer temperature data of the first sensor, and the current signal acquisition module is used to acquire the leakage current data of the second sensor. Both are then sent to the microprocessor for analog-to-digital conversion and transmitted to the cloud server.

[0089] In this preferred embodiment, by synchronously collecting insulation layer temperature data and leakage current data, performing analog-to-digital conversion, the converted data is obtained and transmitted to the cloud server.

[0090] In another preferred embodiment, the first sensor is specifically a distributed optical fiber sensor.

[0091] Specifically, distributed fiber optic sensors can monitor and collect temperature distribution curves of each submarine cable segment using optical time-domain reflectometry to obtain insulation layer temperature data.

[0092] In this preferred embodiment, a distributed optical fiber sensor is used as the first sensor described above.

[0093] In another preferred embodiment, the second sensor is specifically a fluxgate sensor.

[0094] Specifically, the aforementioned fluxgate sensor is characterized by high sensitivity, obtaining the leakage current data by detecting the leakage current flowing through the ground wire.

[0095] In this preferred embodiment, a fluxgate sensor is used as the second sensor described above.

[0096] It should be noted that the device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without creative effort. The above schematic diagram is merely an example of a segmented aging monitoring system for DC submarine cables and does not constitute a limitation on a segmented aging monitoring system for DC submarine cables. It may include more or fewer components than shown, or combine certain components, or use different components.

[0097] Based on the above-described apparatus embodiments, the present invention provides corresponding method embodiments.

[0098] Indicative, such as Figure 3 As shown, another embodiment of the present invention provides a segmented aging monitoring method for DC submarine cables. The above method is applicable to the PC-side analysis platform in the segmented aging monitoring system for DC submarine cables described in any of the above embodiments.

[0099] The above monitoring methods include:

[0100] Step S101: Obtain insulation temperature data and leakage current data of each segment of the DC submarine cable under test; wherein, the insulation temperature data and leakage current data are obtained by the first sensor and the second sensor respectively, and transmitted to the PC-end analysis platform; the submarine cable segments are obtained by dividing the DC submarine cable under test according to the preset segmentation distance.

[0101] Step S102: Based on the above insulation layer temperature data and leakage current data, calculate the aging degree of the corresponding submarine cable segment.

[0102] In a preferred embodiment, the calculation of the aging degree of the corresponding submarine cable segment based on the insulation layer temperature data and leakage current data includes:

[0103] Based on the above insulation temperature data, the average temperature and temperature rise slope of the corresponding submarine cable section were calculated.

[0104] Based on the above leakage current data, the average leakage current of the corresponding submarine cable section was calculated.

[0105] Based on the above average temperature, temperature rise slope, and average leakage current, the aging degree of the corresponding submarine cable section is calculated.

[0106] Specifically, the degree of aging is calculated using the following formula:

[0107]

[0108] In the formula, D(t) represents the degree of aging at time t, k1 represents the weight corresponding to the average leakage current, and I leak The average leakage current is represented by n and m, the material coefficients are represented by k2, and the weight corresponding to the average temperature is represented by E. a k represents the activation energy. B K represents the Boltzmann constant, and k3 represents the weight corresponding to the temperature rise slope. This indicates the temperature rise slope, and T represents the insulation layer temperature data. avg This indicates the average temperature.

[0109] In this preferred embodiment, the aging degree of each submarine cable segment is calculated based on insulation temperature data and leakage current data.

[0110] In another preferred embodiment, after obtaining the aging degree of each submarine cable segment, the method further includes:

[0111] Obtain the first degree of aging corresponding to a healthy submarine cable segment, and the second degree of aging corresponding to a submarine cable segment that is on the verge of breakdown;

[0112] For each segment of the aforementioned DC submarine cable under test, the aging level of each segment is assessed based on the aforementioned aging degree, the aforementioned first aging degree, and the aforementioned second aging degree. If the aforementioned aging level exceeds the preset aging level threshold, an early warning is issued for the corresponding submarine cable segment.

[0113] Specifically, when an excessively aged section of a submarine cable is detected, an early warning message will be sent in a timely manner to facilitate timely maintenance of the corresponding section.

[0114] In this preferred embodiment, the aging levels of each submarine cable segment are classified according to the first aging level and the second aging level, and an early warning is issued for submarine cable segments with excessive aging levels.

[0115] The above are preferred embodiments 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 are also considered to be within the scope of protection of the present invention.

Claims

1. A segmented aging monitoring system for a DC submarine cable, characterized in that, include: First sensor, second sensor, and PC-based analysis platform; The first sensor is embedded between the insulation layer and the alloy lead sheath of each segment of the DC submarine cable under test along the length direction of the cable. The second sensor is deployed on the outer surface of each segment of the cable and connected to the ground wire of the corresponding segment. The cable segments are obtained by dividing the DC submarine cable under test according to a preset segmentation distance. The first sensor is used to monitor the insulation temperature data of the corresponding submarine cable segment in real time and transmit the insulation temperature data to the PC-based analysis platform. The second sensor is used to monitor the leakage current data of the corresponding submarine cable segment in real time and transmit the leakage current data to the PC-based analysis platform. The PC-based analysis platform is used to calculate the aging degree of the corresponding submarine cable segment based on the insulation layer temperature data and leakage current data.

2. The segmented aging monitoring system for a DC submarine cable according to claim 1, characterized in that, The step of calculating the aging degree of the corresponding submarine cable segment based on the insulation layer temperature data and leakage current data includes: Based on the insulation layer temperature data, the average temperature and temperature rise slope of the corresponding submarine cable segment are calculated. Based on the leakage current data, the average leakage current of the corresponding submarine cable segment is calculated; The degree of aging of the corresponding submarine cable segment is calculated based on the average temperature, temperature rise slope, and average leakage current.

3. The segmented aging monitoring system for a DC submarine cable according to claim 2, characterized in that, The PC-based analysis platform is also used for: Obtain the first degree of aging corresponding to a healthy submarine cable segment, and the second degree of aging corresponding to a submarine cable segment that is on the verge of breakdown; For each segment of the DC submarine cable under test, the aging level of each segment is evaluated based on the aging degree, the first aging degree, and the second aging degree. If the aging level is greater than a preset aging level threshold, an early warning is issued for the corresponding segment.

4. The segmented aging monitoring system for a DC submarine cable according to claim 3, characterized in that, Also includes: Signal relay processing unit and cloud server; The signal relay processing unit is communicatively connected to the first sensor, the second sensor, and the cloud server, respectively. The signal relay processing unit is used to receive insulation layer temperature data and leakage current data emitted by the first sensor and the second sensor, and send the insulation layer temperature data and leakage current data to the cloud server. The cloud server is used to store the insulation layer temperature data and leakage current data after receiving them, and simultaneously send them to the PC-based analysis platform.

5. The segmented aging monitoring system for a DC submarine cable according to claim 4, characterized in that, The signal relay processing unit further includes: It integrates an optical signal demodulation module, a current signal acquisition module, and a microprocessor; The integrated optical signal demodulation module is used to receive the insulation layer temperature data emitted by the first sensor and send the insulation layer temperature data to the microprocessor; The current signal acquisition module is used to receive leakage current data emitted by the first sensor and send the leakage current data to the microprocessor; The microprocessor is used to convert the insulation layer temperature data and leakage current data from analog to digital and then send them to the cloud server.

6. The segmented aging monitoring system for a DC submarine cable according to claim 5, characterized in that, The first sensor is specifically a distributed optical fiber sensor.

7. The segmented aging monitoring system for a DC submarine cable according to claim 6, characterized in that, The second sensor is specifically a fluxgate sensor.

8. A method for segmented aging monitoring of a DC submarine cable, characterized in that, The PC-based analysis platform is applicable to the segmented aging monitoring system for DC submarine cables as described in claims 1-7. The monitoring method includes: The insulation temperature data and leakage current data of each segment of the DC submarine cable under test are acquired; wherein the insulation temperature data and the leakage current data are monitored by a first sensor and a second sensor, respectively, and transmitted to the PC-based analysis platform; the submarine cable segments are obtained by dividing the DC submarine cable under test according to a preset segmentation distance; Based on the insulation temperature data and leakage current data, the aging degree of the corresponding submarine cable segment is calculated.

9. The method for segmented aging monitoring of a DC submarine cable according to claim 8, characterized in that, The step of calculating the aging degree of the corresponding submarine cable segment based on the insulation layer temperature data and leakage current data includes: Based on the insulation layer temperature data, the average temperature and temperature rise slope of the corresponding submarine cable segment are calculated. Based on the leakage current data, the average leakage current of the corresponding submarine cable segment is calculated; The degree of aging of the corresponding submarine cable segment is calculated based on the average temperature, temperature rise slope, and average leakage current.

10. The method for segmented aging monitoring of a DC submarine cable according to claim 9, characterized in that, After obtaining the aging degree of each submarine cable segment, the following is also included: Obtain the first degree of aging corresponding to a healthy submarine cable segment, and the second degree of aging corresponding to a submarine cable segment that is on the verge of breakdown; For each segment of the DC submarine cable under test, the aging level of each segment is evaluated based on the aging degree, the first aging degree, and the second aging degree. If the aging level is greater than a preset aging level threshold, an early warning is issued for the corresponding segment.

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