A low-frequency submarine cable dynamic capacity increasing method, system, device, equipment and storage medium

Abstract

The application discloses a kind of low-frequency submarine cable dynamic capacity increasing method, system, device, equipment and storage medium, belong to submarine cable power transmission technical field.The method comprises: the low-frequency submarine cable is divided into multiple thermal sections;Through the parameter iterative update of the electric-thermal coupling model of each thermal section by minimizing temperature residual function, the electric-thermal coupling model of each thermal section is calibrated by temperature measurement;Temperature residual function is determined based on the predicted conductor hot spot temperature and actual conductor hot spot temperature of each thermal section;Based on the electric-thermal coupling model of each thermal section calibrated by temperature measurement, under target constraint condition, with maximum power transmission as target, operating frequency and transmission current are optimized, to obtain target operating frequency and target transmission current;Target operating frequency is sent to shore frequency converter, and target transmission current is sent to power transmission system.The safety and reliability of submarine cable capacity increasing control can be improved by using the technical scheme provided by the application.

Description

Technical Field

[0001] This invention relates to the field of submarine cable power transmission technology, and in particular to a method, system, device, equipment and storage medium for dynamic capacity expansion of low-frequency submarine cables. Background Technology

[0002] Low-frequency AC (LFAC) power transmission reduces the operating frequency of submarine cables to non-standard frequencies such as 16.7Hz and 20Hz, thereby decreasing the capacitive charging current and reactive power along the cable route. This expands the economical transmission distance of AC submarine cables and increases the active power that can be transmitted. As deep-sea wind power and transoceanic power transmission projects develop towards longer distances and larger capacities, the safe and efficient operation of low-frequency submarine cables has become a key technical issue.

[0003] The permissible current-carrying capacity of submarine cables depends on the balance between conductor heating and heat dissipation from the surrounding medium. Existing projects often calculate the rated current-carrying capacity based on design parameters such as fixed environmental thermal resistance, soil temperature, and burial depth, according to standards like IEC 60287, and set the upper limit of long-term operating power accordingly. However, the submarine environment exhibits significant time-varying characteristics: seasonal changes in seawater temperature, seabed sediment accumulation, erosion-induced changes in burial depth, and variations in ocean current heat transfer can all cause drift in heat dissipation conditions, making the "static rated current-carrying capacity" conservative or mismatched in actual operation.

[0004] Furthermore, the electrical parameters and loss mechanisms of cables under low-frequency excitation exhibit significant frequency-dependent relationships. For example, the cable charging current is frequency-dependent, the sheath circulating current is related to its loop impedance and frequency-dependent induced voltage, and the dielectric loss is related to parameters such as frequency and the insulation dielectric loss tangent. If the upper limit of the allowable current transmission of the cable is determined solely based on a one-time modeling result at a fixed frequency, and the temperature measurement results are directly substituted without online calibration of the model parameters, it can easily lead to conservative or uncertain capacity expansion decisions, making it difficult to fully unleash the power transmission potential of low-frequency submarine cables.

[0005] Therefore, a more reliable solution is needed for dynamic capacity expansion of low-frequency submarine cables. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, system, device, equipment and storage medium for dynamic capacity expansion of low-frequency submarine cables, which can improve the safety and reliability of submarine cable capacity expansion control, thereby fully releasing the power transmission potential of low-frequency submarine cables.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] On one hand, the present invention provides a method for dynamic capacity expansion of low-frequency submarine cables, the method comprising:

[0009] The conductor temperature distribution along the cable and the seabed ambient temperature are collected by integrating the built-in optical fiber into the low-frequency submarine cable and laying the external optical fiber parallel to the cable.

[0010] Based on the burial method of the low-frequency submarine cable, the low-frequency submarine cable is divided into multiple thermal sections.

[0011] By minimizing the temperature residual function under the current operating conditions and seabed temperature environment, the parameters of the electrothermal coupling model for each thermal section are iteratively updated to obtain a temperature-calibrated electrothermal coupling model for each thermal section. The current operating conditions include the current operating frequency and the current transmission current. The temperature residual function is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature for each thermal section. The predicted conductor hot spot temperature for each thermal section is determined based on the electrothermal coupling model for each thermal section. The actual conductor hot spot temperature for each thermal section is determined based on the conductor temperature distribution along the line.

[0012] Based on the temperature-calibrated electrothermal coupling model of each thermal section, under the target constraint conditions, with the goal of maximizing the transmission power, the operating frequency and transmission current are optimized in a coordinated manner to obtain the target operating frequency and target transmission current.

[0013] The target operating frequency is sent to the shore-end frequency converter to adjust the submarine cable operating frequency to the target operating frequency; the target transmission current is sent to the power transmission system so that the submarine cable transmission current regulated by the power transmission system is less than or equal to the target transmission current.

[0014] In some possible implementations, the step of iteratively updating the parameters of the electrothermal coupling model for each thermal section by minimizing the temperature residual function under the current operating conditions and seabed temperature environment, to obtain a temperature-calibrated electrothermal coupling model for each thermal section, includes:

[0015] Based on the current operating conditions and seabed ambient temperature, and using the electrothermal coupling model of each thermal section, the predicted conductor hot spot temperature of each thermal section is determined.

[0016] The temperature residual of each thermal section is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature of each thermal section.

[0017] When the temperature residual is greater than the temperature threshold, a temperature residual function is determined based on the temperature residual of each thermal section, as shown in the following formula:

[0018] ;

[0019] in, ;

[0020] in, Represents the temperature residual function. This represents the weight corresponding to the temperature residual of the i-th thermal section; This represents the temperature residual corresponding to the i-th thermal section. This represents the actual conductor hot spot temperature of the i-th thermal section. This represents the predicted conductor hot spot temperature of the i-th thermal section; represents the parameters of the electrothermal coupling model for the i-th thermal section. The initial parameters represent the electrothermal coupling model of the i-th thermal section; Represents the regularization coefficient;

[0021] The parameters of the electrothermal coupling model for each thermal section are shown in the following equation:

[0022] ;

[0023] in, This represents the equivalent external thermal resistance of the seabed corresponding to the i-th thermal section. This represents the correction factor for the sheath circulation loss in the i-th thermal section. This represents the armor circulation loss correction coefficient for the i-th thermal section;

[0024] By minimizing the temperature residual function, the parameters of the electrothermal coupling model for each thermal section are iteratively updated to obtain a temperature-calibrated electrothermal coupling model for each thermal section.

[0025] In some possible implementations, determining the predicted conductor hot spot temperature of each thermal section based on the electrothermal coupling model of each thermal section, according to the current operating conditions and seabed ambient temperature, includes:

[0026] Based on the current operating conditions and seabed ambient temperature, and using the operating temperature mapping database for each thermal section, the predicted conductor hot spot temperature for each thermal section is determined.

[0027] The operating temperature mapping database for each thermal section is constructed based on the electrothermal coupling model of each thermal section; the operating temperature mapping database for each thermal section is constructed in the following manner:

[0028] By scanning the operating parameters of the electrothermal coupling model of each thermal section, the conductor hot spot temperature under the operating parameters of each thermal section is determined; the operating parameters include operating frequency, transmission current, seabed ambient temperature, seabed equivalent thermal resistance, and burial depth.

[0029] Based on the conductor hot spot temperature under the operating parameters of each thermal section, the mapping relationship between the operating parameters and the conductor hot spot temperature is determined, and the operating temperature mapping database of each thermal section is obtained.

[0030] In some possible implementations, the temperature-calibrated electrothermal coupling model based on each thermal section, under target constraints, aims to maximize the transmission power by co-optimizing the operating frequency and transmission current to obtain the target operating frequency and target transmission current, including:

[0031] Based on the temperature-calibrated electrothermal coupling model of each thermal section, the predicted conductor hot spot temperature of each thermal section is determined;

[0032] The target constraint conditions are defined as follows: the predicted conductor hot spot temperature of each thermal section is less than or equal to the maximum allowable conductor temperature, and the converter capacity is less than or equal to the capacity threshold.

[0033] The objective function is to maximize the transmission power, as shown in the following equation:

[0034] ;

[0035] in, Indicates the transmission power. Indicates the current operating frequency. Indicates the current being transmitted; Indicates line voltage. Indicates the operating frequency is And the transmission current is The power factor corresponding to the time;

[0036] Based on the temperature-calibrated electrothermal coupling model of each thermal section, under the target constraints, the operating frequency and the transmission current are optimized in conjunction with the objective function to obtain the target operating frequency and the target transmission current.

[0037] In some possible implementations, the method further includes:

[0038] Based on the target transmission current, determine the maximum safe transmission power at the target operating frequency;

[0039] The maximum safe transmission power is sent to the power transmission system so that the power transmission system adjusts the transmission power according to a preset ramp rate when the conductor hot spot temperature is lower than the difference between the conductor's maximum allowable temperature and the temperature margin; wherein the adjusted actual transmission power is less than the maximum safe transmission power.

[0040] In some possible implementations, the parameters of the electrothermal coupling model for each thermal section are iteratively updated using the least squares method or the extended Kalman filter method.

[0041] On the other hand, the present invention provides a dynamic capacity expansion system for low-frequency submarine cables. The system includes: a distributed optical fiber temperature measurement device, a control device, a power transmission system, and a shore-end frequency converter. The distributed optical fiber temperature measurement device is connected to the built-in optical fiber and the external optical fiber of the low-frequency submarine cable, respectively. The control device is connected to the distributed optical fiber temperature measurement device, the power transmission system is connected to the control device, and the shore-end frequency converter is connected to the control device.

[0042] The distributed optical fiber temperature measurement device is used to receive a first optical fiber output signal transmitted by the built-in optical fiber integrated in the low-frequency submarine cable to determine the conductor temperature distribution along the line; and to receive a second optical fiber output signal transmitted by an external optical fiber laid parallel to the cable to determine the seabed ambient temperature.

[0043] The control device is used to receive the conductor temperature distribution along the line and the seabed ambient temperature sent by the distributed optical fiber temperature measurement device, and to execute the low-frequency submarine cable dynamic capacity expansion method as described above to generate the target operating frequency and the target transmission current.

[0044] The shore-end frequency converter is used to receive the target operating frequency sent by the control device and adjust the submarine cable operating frequency to the target operating frequency;

[0045] The power transmission system is used to receive the target transmission current sent by the control device and adjust the submarine cable transmission current so that the submarine cable transmission current is less than or equal to the target transmission current.

[0046] On the other hand, the present invention provides a dynamic capacity expansion device for low-frequency submarine cables, the device comprising:

[0047] The temperature acquisition module is used to collect the conductor temperature distribution along the cable and the seabed ambient temperature through the built-in optical fiber integrated into the low-frequency submarine cable and the external optical fiber laid parallel to the cable, respectively.

[0048] The model update module is used to divide the low-frequency submarine cable into multiple thermal sections according to the burial method of the low-frequency submarine cable; by minimizing the temperature residual function under the current operating conditions and seabed temperature environment, the parameters of the electrothermal coupling model of each thermal section are iteratively updated to obtain the temperature-calibrated electrothermal coupling model of each thermal section; the current operating conditions include the current operating frequency and the current transmission current; the temperature residual function is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature of each thermal section; the predicted conductor hot spot temperature of each thermal section is determined based on the electrothermal coupling model of each thermal section; the actual conductor hot spot temperature of each thermal section is determined based on the conductor temperature distribution along the line.

[0049] The collaborative optimization module is used to collaboratively optimize the operating frequency and the transmission current based on the temperature-calibrated electrothermal coupling model of each thermal section, under target constraints, with the goal of maximizing the transmission power, to obtain the target operating frequency and the target transmission current.

[0050] The capacity expansion module is used to send the target operating frequency to the shore-end frequency converter to adjust the submarine cable operating frequency to the target operating frequency; and to send the target transmission current to the power transmission system so that the submarine cable transmission current adjusted by the power transmission system is less than or equal to the target transmission current.

[0051] On the other hand, an electronic device is provided, the device including a processor and a memory, the memory storing at least one instruction and at least one program, the at least one instruction and the at least one program being loaded and executed by the processor to implement the low-frequency submarine cable dynamic capacity expansion method as described above.

[0052] On the other hand, a computer-readable storage medium is provided, wherein at least one instruction and at least one program are stored therein, the at least one instruction and the at least one program being loaded and executed by a processor to implement the low-frequency submarine cable dynamic capacity expansion method as described above.

[0053] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0054] In this invention, the conductor temperature distribution along the cable and the seabed ambient temperature are collected by integrating built-in optical fibers into the low-frequency submarine cable and laying external optical fibers parallel to the cable. Based on the cable's burial method, the low-frequency submarine cable is divided into multiple thermal sections. Then, by minimizing the temperature residual function under the current operating conditions and seabed temperature environment, the parameters of the electrothermal coupling model for each thermal section are iteratively updated to obtain a temperature-calibrated electrothermal coupling model for each thermal section. The current operating conditions include the current operating frequency and the current transmission current. The temperature residual function is determined based on the predicted and actual conductor hot spot temperatures for each thermal section. The predicted conductor hot spot temperature for each thermal section is determined based on the electrothermal coupling model for that section. The actual conductor hot spot temperature for each thermal section is determined based on the conductor temperature distribution along the cable. By using the conductor temperature information provided by distributed temperature measurement to calibrate the electrothermal coupling model for each thermal section, the uncertainties in the environment and model parameters can be eliminated, improving the consistency between the model and the actual operating conditions. This improves the accuracy and effectiveness of subsequent coordinated optimization of operating frequency and transmission current, thereby enhancing the safety and effectiveness of capacity expansion control. Then, based on the temperature-calibrated electrothermal coupling model of each thermal section, under target constraints, the operating frequency and transmission current are coordinated and optimized with the goal of maximizing transmission power, resulting in the target operating frequency and target transmission current. Introducing the "non-standard frequency selectable" characteristic into dynamic capacity expansion control, and co-optimizing the operating frequency and transmission current under target constraints based on the temperature-calibrated electrothermal coupling model of each thermal section, avoids conservative capacity expansion decisions under fixed frequencies, thus enabling capacity expansion control under non-standard frequencies and releasing the transmission potential of low-frequency submarine cables. Next, the target operating frequency is sent to the shore-end frequency converter to adjust the submarine cable operating frequency to the target operating frequency; the target transmission current is sent to the transmission system so that the transmission system-regulated submarine cable transmission current is less than or equal to the target transmission current, ensuring the safety and effectiveness of low-frequency submarine cable capacity expansion control and improving the transmission capacity of the submarine cable. Attached Figure Description

[0055] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 This is a flowchart illustrating a method for dynamic capacity expansion of low-frequency submarine cables provided in an embodiment of the present invention;

[0057] Figure 2 This is a schematic diagram of a low-frequency submarine cable dynamic capacity expansion system provided in an embodiment of the present invention;

[0058] Figure 3 This is a schematic diagram of a low-frequency submarine cable dynamic capacity expansion device provided in an embodiment of the present invention.

[0059] In the diagram: 1. Internal optical fiber; 2. External optical fiber; 3. Low-frequency submarine cable. Detailed Implementation

[0060] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0061] 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 non-exclusive inclusion; for example, a process, method, system, product, or server 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 devices.

[0062] In this embodiment of the invention, the terms "module" or "unit" refer to a computer program or part of a computer program that has a predetermined function and works with other related parts to achieve a predetermined goal, and can be implemented wholly or partially using software, hardware (such as processing circuitry or memory), or a combination thereof. Similarly, a processor (or multiple processors or memory) can be used to implement one or more modules or units. Furthermore, each module or unit can be part of an overall module or unit that includes the functionality of that module or unit.

[0063] Various exemplary embodiments, features, and aspects of the present invention will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0064] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0065] In this document, 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 three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0066] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art will understand that the present invention can be practiced without certain specific details. In some instances, methods, means, elements, and circuits well known to those skilled in the art have not been described in detail in order to highlight the spirit of the invention.

[0067] Figure 1 This is a flowchart illustrating a method for dynamically increasing the capacity of low-frequency submarine cables according to an embodiment of the present invention. This specification provides the method operation steps as shown in the embodiments or flowcharts, but based on conventional or non-inventive methods, more or fewer operation steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual system or server product execution, the method can be executed in the order shown in the embodiments or drawings, or in parallel (e.g., in a parallel processor or multi-threaded processing environment). Specifically, as shown... Figure 1 As shown, the above method may include:

[0068] S101: The conductor temperature distribution along the cable and the seabed ambient temperature are collected by the built-in optical fiber integrated into the low-frequency submarine cable and the external optical fiber laid parallel to the cable.

[0069] In one specific embodiment, distributed fiber optic temperature measurement is used to acquire the initial conductor temperature distribution along the cable and the initial seabed ambient temperature using an embedded optical fiber integrated into the low-frequency submarine cable and an external optical fiber laid parallel to the cable. The initial conductor temperature distribution and the initial seabed ambient temperature can then be preprocessed to obtain the conductor temperature distribution along the cable and the seabed ambient temperature. Optionally, the preprocessing of the initial conductor temperature distribution and the initial seabed ambient temperature may include filtering, outlier removal, interpolation reconstruction of missing temperature measurement points along the cable, and time synchronization.

[0070] In one specific embodiment, when the highest conductor temperature in the conductor temperature distribution along the cable is greater than or equal to the highest permissible conductor temperature, a power limiting command or a frequency reduction command is sent.

[0071] S102: Based on the burial method of the low-frequency submarine cable, the low-frequency submarine cable is divided into multiple thermal sections;

[0072] In one specific embodiment, the laying method of the low-frequency submarine cable may include direct burial, trench burial, and pipeline burial. Based on the laying method, the length of the low-frequency submarine cable is divided into multiple thermal sections. Optionally, the length of each thermal section can be determined according to the laying method, and optionally, the length of each thermal section can be 0.5~5km. Optionally, an electrothermal coupling model related to the operating frequency can be established for each thermal section.

[0073] S103: By minimizing the temperature residual function under the current operating conditions and seabed temperature environment, the parameters of the electrothermal coupling model of each thermal section are iteratively updated to obtain the temperature-calibrated electrothermal coupling model of each thermal section.

[0074] In one specific embodiment, the current operating conditions include the current operating frequency and the current transmission current; the temperature residual function is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature of each thermal section, the predicted conductor hot spot temperature of each thermal section is determined based on the electrothermal coupling model of each thermal section; the actual conductor hot spot temperature of each thermal section is determined based on the conductor temperature distribution along the line.

[0075] In one specific embodiment, an electrothermal coupling model related to the operating frequency is established in a finite element environment based on the structural parameters and burial method of the low-frequency submarine cable. This facilitates subsequent combined scanning of operating parameters and generation of an operating temperature mapping database. The structural parameters of the low-frequency submarine cable may include conductor, insulation, metal shielding, armor, and outer sheath.

[0076] In an optional embodiment, the above-mentioned iterative update of the parameters of the electrothermal coupling model for each thermal section by minimizing the temperature residual function under the current operating conditions and seabed temperature environment, to obtain a temperature-calibrated electrothermal coupling model for each thermal section, may include:

[0077] Based on the current operating conditions and seabed ambient temperature, the predicted conductor hot spot temperature of each thermal section is determined using the electrothermal coupling model for each thermal section.

[0078] The temperature residual for each thermal section is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature for each thermal section.

[0079] When the temperature residual is greater than the temperature threshold, the temperature residual function is determined based on the temperature residual of each thermal section, as shown in the following formula:

[0080] ;

[0081] in, ;

[0082] in, Represents the temperature residual function; This represents the weight corresponding to the temperature residual of the i-th thermal section; This represents the temperature residual corresponding to the i-th thermal section. This represents the actual conductor hot spot temperature of the i-th thermal section. This represents the predicted conductor hot spot temperature of the i-th thermal section; represents the parameters of the electrothermal coupling model for the i-th thermal section. The initial parameters represent the electrothermal coupling model of the i-th thermal section; Represents the regularization coefficient;

[0083] The parameters of the electrothermal coupling model for each thermal section are shown in the following equation:

[0084] ;

[0085] in, This represents the equivalent external thermal resistance of the seabed corresponding to the i-th thermal section. This represents the correction factor for the sheath circulation loss in the i-th thermal section. This represents the armor circulation loss correction coefficient for the i-th thermal section;

[0086] By minimizing the temperature residual function, the parameters of the electrothermal coupling model for each thermal section are iteratively updated to obtain the temperature-calibrated electrothermal coupling model for each thermal section.

[0087] In one specific embodiment, the predicted conductor hot spot temperature for each thermal section can be the highest temperature of the conductor corresponding to each thermal section predicted based on the electrothermal coupling model of each thermal section.

[0088] In an optional embodiment, determining the predicted conductor hotspot temperature for each thermal section based on the electrothermal coupling model of each thermal section, according to the current operating conditions and seabed ambient temperature, may include:

[0089] Based on the current operating conditions and seabed ambient temperature, and using the operating temperature mapping database for each thermal section, the predicted conductor hot spot temperature for each thermal section is determined.

[0090] The operating temperature mapping database for each thermal section is constructed based on the electrothermal coupling model of each thermal section; the operating temperature mapping database for each thermal section is constructed in the following manner:

[0091] By scanning the operating parameters of the electrothermal coupling model for each thermal section, the conductor hot spot temperature under the operating parameters of each thermal section is determined; the operating parameters include operating frequency, transmission current, seabed ambient temperature, seabed equivalent thermal resistance, and burial depth.

[0092] Based on the conductor hot spot temperature under the operating parameters of each thermal section, the mapping relationship between the operating parameters and the conductor hot spot temperature is determined, and the operating temperature mapping database for each thermal section is obtained.

[0093] In one specific embodiment, operating condition parameters may include cable operating condition parameters and cable environmental parameters. Specifically, operating condition parameters include operating frequency, transmission current, seabed ambient temperature, seabed equivalent thermal resistance, and burial depth. Optionally, the cable operating condition parameters include operating frequency and transmission current, and the operating condition temperature mapping database can characterize the mapping relationship between cable operating conditions and conductor hot spot temperature. Specifically, the operating condition temperature mapping database can characterize the mapping relationship between operating frequency, transmission current, and conductor hot spot temperature. Optionally, the operating condition temperature mapping database can characterize the mapping relationship between operating frequency, transmission current, cable environment, and conductor hot spot temperature, and cable environmental parameters may include seabed ambient temperature, burial depth, and seabed equivalent thermal resistance. Specifically, the operating condition temperature mapping database can be used to determine the conductor hot spot temperature based on operating frequency, transmission current, seabed ambient temperature, burial depth, and seabed equivalent thermal resistance.

[0094] In one specific embodiment, based on the operating temperature mapping database for each thermal section, the predicted conductor hot spot temperature for each thermal condition corresponding to the current operating frequency, current transmission current, and seabed ambient temperature is determined.

[0095] In one specific embodiment, the actual conductor hot spot temperature of each thermal section can be the actual highest temperature of the conductor corresponding to each thermal section; the actual conductor hot spot temperature of each thermal section can be determined based on the conductor temperature distribution along the line. Optionally, the highest conductor temperature of each thermal section is determined based on the conductor temperature distribution along the line; the highest conductor temperature of each thermal section is then determined as the actual conductor hot spot temperature of each thermal section.

[0096] In one specific embodiment, the temperature residual for each thermal section is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature for each thermal section. Optionally, the temperature threshold can be set according to actual application requirements. When the temperature residual is greater than the temperature threshold, the temperature residual function is determined based on the weighted sum of squares of each thermal section. By minimizing the temperature residual function, the parameters of the electrothermal coupling model for each thermal section are iteratively updated to obtain the temperature-calibrated electrothermal coupling model for each thermal section. Optionally, the parameters of the electrothermal coupling model for each thermal section include the seabed equivalent external thermal resistance, the sheath circulation loss correction coefficient, and the armor circulation loss correction coefficient. After iteratively updating the parameters of the electrothermal coupling model for each thermal section, the calibrated seabed equivalent external thermal resistance, sheath circulation loss correction coefficient, and armor circulation loss correction coefficient for each thermal section can be output, thus obtaining the temperature-calibrated electrothermal coupling model for each thermal section. Optionally, the independent equivalent external thermal resistance of the seabed configured for each thermal section can enable the temperature-calibrated electrothermal coupling model of each thermal section to characterize the impact of the corresponding burial depth variation, seabed sediment accumulation, and soil thermal resistance non-uniformity on heat dissipation capacity.

[0097] In an optional embodiment, the parameters of the electrothermal coupling model for each thermal section are iteratively updated using the least squares method or the extended Kalman filter method.

[0098] In one specific embodiment, the parameters of the electrothermal coupling model for each thermal section are iteratively updated using weighted least squares, recursive least squares, or extended Kalman filtering.

[0099] In the above embodiments, the conductor temperature information provided by distributed temperature measurement is used to perform temperature measurement and calibration on the electrothermal coupling model of each thermal section to eliminate the uncertainty of environmental and structural parameters, thereby improving the accuracy and effectiveness of subsequent coordinated optimization of operating frequency and transmission current, and thus improving the safety and effectiveness of capacity expansion control.

[0100] S104: Based on the temperature-calibrated electrothermal coupling model of each thermal section, under the target constraint, with the goal of maximizing the transmission power, the operating frequency and transmission current are optimized in a coordinated manner to obtain the target operating frequency and target transmission current.

[0101] In an optional embodiment, the above-described electrothermal coupling model based on temperature measurement and calibration for each thermal section, under target constraints, optimizes the operating frequency and transmission current in a coordinated manner with the goal of maximizing transmission power, and the target operating frequency and target transmission current may include:

[0102] Based on the temperature-calibrated electrothermal coupling model of each thermal section, the predicted temperature of the conductor hot spot in each thermal section is determined.

[0103] The target constraints are defined as the predicted conductor hot spot temperature of each thermal section being less than or equal to the maximum allowable conductor temperature, and the converter capacity being less than or equal to the capacity threshold.

[0104] The objective function is to maximize the transmission power, as shown in the following equation:

[0105] ;

[0106] in, Indicates the transmission power. Indicates the current operating frequency. Indicates the current being transmitted; Indicates line voltage. Indicates the operating frequency is And the transmission current is The power factor corresponding to the time;

[0107] Based on the temperature-calibrated electrothermal coupling model of each thermal section, under the target constraints, the operating frequency and the transmission current are optimized in a coordinated manner according to the objective function to obtain the target operating frequency and the target transmission current.

[0108] In one specific embodiment, the predicted conductor hotspot temperature for each thermal section can be the highest temperature of the conductor corresponding to each thermal section predicted based on a temperature-calibrated electrothermal coupling model for each thermal section. Optionally, determining the predicted conductor hotspot temperature for each thermal section based on the temperature-calibrated electrothermal coupling model for each thermal section may include: updating the operating condition temperature mapping database for each thermal section based on the temperature-calibrated electrothermal coupling model for each thermal section to obtain an updated operating condition temperature mapping database for each thermal condition; and determining the predicted conductor hotspot temperature for each thermal section based on the updated operating condition mapping database according to the current operating conditions and seabed ambient temperature.

[0109] In one specific embodiment, the predicted hot spot temperature of the conductor in each thermal section is less than or equal to the maximum allowable temperature of the conductor, i.e. , Indicates the predicted temperature of the conductor's hot spot. The maximum allowable temperature of the conductor and the converter capacity being less than or equal to the capacity threshold are defined as the target constraints. Optionally, based on the temperature-calibrated electrothermal coupling model of each thermal section, under the target constraints, the operating frequency and transmission current are co-optimized with the goal of maximizing transmission power to obtain the target operating frequency and target transmission current. Optionally, the maximum safe transmission power at the target operating frequency can be determined based on the target transmission current.

[0110] In one specific embodiment, the optimization range of the target operating frequency for collaborative optimization can be 5~25Hz.

[0111] In a specific embodiment, the coordinated optimization of operating frequency and transmission current can be achieved through frequency discrete scanning and one-dimensional current search. Specifically, values ​​are taken point by point within a preset frequency range, and for each candidate operating frequency, the bisection method is used to solve for the required parameters under the temperature-calibrated electrothermal coupling model of each thermal section. Maximum allowable current and calculate Verification during this process ,as well as ,in, Indicates apparent power. Indicates active power. Indicates reactive power. This indicates the rated apparent power of the frequency converter. This indicates the voltage drop across the line. Indicates the maximum allowable voltage drop of the line; ultimately determine... Maximum operating frequency For the target operating frequency, according to The determined transmission current is the target transmission current.

[0112] In the above embodiments, the "non-standard frequency selectability" feature can be utilized to optimize the operating frequency and transmission current in a coordinated manner based on the temperature-calibrated electrothermal coupling model of each thermal section under target constraints. This improves the reliability and effectiveness of determining the operating frequency and transmission current. Furthermore, by sending the optimized target operating frequency and target transmission current to the shore-end frequency converter and the power transmission system, the safety and effectiveness of capacity expansion control can be realized and improved, and the submarine cable transmission capacity can be increased under safe conditions.

[0113] S105: Send the target operating frequency to the shore-end frequency converter to adjust the submarine cable operating frequency to the target operating frequency; send the target transmission current to the power transmission system so that the submarine cable transmission current regulated by the power transmission system is less than or equal to the target transmission current.

[0114] In one specific embodiment, the target transmission current is sent to the power transmission system as a scheduling upper limit value so that the submarine cable transmission current regulated by the power transmission system is less than or equal to the target transmission current.

[0115] In an optional embodiment, the above method may further include:

[0116] Determine the maximum safe transmission power at the target operating frequency based on the target transmission current;

[0117] The maximum safe transmission power is sent to the power transmission system so that the power transmission system can adjust the transmission power according to the preset ramp rate when the conductor hot spot temperature is lower than the difference between the conductor's maximum allowable temperature and the temperature margin; wherein the actual transmission power adjusted is less than the maximum safe transmission power.

[0118] In one specific embodiment, the maximum safe transmission power is sent to the power transmission system as a scheduling upper limit. This ensures that the power transmission power of the submarine cable, adjusted by the power transmission system according to a preset ramp rate and temperature margin, is less than or equal to the maximum safe transmission power. This allows the actual transmission power to dynamically approach the maximum safe transmission power without overheating the conductor, thus achieving capacity expansion. Optionally, when adjusting the submarine cable transmission power, a power limiting or frequency reduction command is triggered when the conductor hotspot temperature is greater than or equal to the conductor's maximum allowable temperature. Optionally, the temperature margin can be a safety margin between a preset maximum allowable conductor temperature and the actual conductor temperature.

[0119] This invention also provides a dynamic capacity expansion system for low-frequency submarine cables. Figure 2 This is a schematic diagram of a low-frequency submarine cable dynamic capacity expansion system provided in an embodiment of the present invention; as shown below. Figure 2 As shown, the above system includes: a distributed optical fiber temperature measurement device, a control device, a power transmission system, and a shore-end frequency converter. The distributed optical fiber temperature measurement device is connected to the built-in optical fiber of the low-frequency submarine cable and the external optical fiber of the low-frequency submarine cable, respectively. The control device is connected to the distributed optical fiber temperature measurement device, the power transmission system is connected to the control device, and the shore-end frequency converter is connected to the control device.

[0120] The distributed optical fiber temperature measurement device is used to receive the first optical fiber output signal sent by the built-in optical fiber 1 integrated in the low-frequency submarine cable 3 to determine the conductor temperature distribution along the line; and to receive the second optical fiber output signal sent by the external optical fiber 2 laid parallel to the cable to determine the seabed ambient temperature.

[0121] The control device is used to receive the conductor temperature distribution along the line and the seabed ambient temperature sent by the distributed optical fiber temperature measurement device, and to execute the low-frequency submarine cable dynamic capacity expansion method as described in any one of the method embodiments to generate the target operating frequency and the target transmission current.

[0122] The shore-end frequency converter is used to receive the target operating frequency sent by the control device and adjust the submarine cable operating frequency to the target operating frequency;

[0123] The power transmission system is used to receive the target transmission current sent by the control device and adjust the submarine cable transmission current so that the submarine cable transmission current is less than or equal to the target transmission current.

[0124] In one specific embodiment, the spacing between the external optical fiber of the low-frequency submarine cable and the parallel laying of the low-frequency submarine cable can be set according to the actual application requirements. Specifically, the spacing can be 0.5-1m to reduce the interference of the submarine cable's heat generation on the seabed ambient temperature measured by the external optical fiber.

[0125] As can be seen from the technical solutions provided in the embodiments of this specification above, this specification uses an embedded optical fiber integrated into the low-frequency submarine cable and an external optical fiber laid parallel to the cable to collect the conductor temperature distribution along the cable and the seabed ambient temperature, respectively. Based on the burial method of the low-frequency submarine cable, the cable is divided into multiple thermal sections. Then, by minimizing the temperature residual function under the current operating conditions and seabed temperature environment, the parameters of the electrothermal coupling model for each thermal section are iteratively updated to obtain a temperature-calibrated electrothermal coupling model for each thermal section. The current operating conditions include the current operating frequency and the current transmission current. The temperature residual function is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature for each thermal section. The predicted conductor hot spot temperature for each thermal section is determined based on the electrothermal coupling model for each thermal section. The actual conductor hot spot temperature for each thermal section is determined based on the conductor temperature distribution along the cable. By using the conductor temperature information along the cable provided by distributed temperature measurement to calibrate the electrothermal coupling model for each thermal section, the uncertainties of the environment and model parameters can be eliminated, improving efficiency. The consistency between the model and actual operating conditions improves the accuracy and effectiveness of subsequent coordinated optimization of operating frequency and transmission current, thereby enhancing the safety and effectiveness of capacity expansion control. Then, based on the temperature-calibrated electrothermal coupling model for each thermal section, under target constraints, the operating frequency and transmission current are coordinated and optimized with the goal of maximizing transmission power, yielding the target operating frequency and target transmission current. The "non-standard frequency selectable" characteristic is introduced into dynamic capacity expansion control. Coordinated optimization of operating frequency and transmission current under target constraints, based on the temperature-calibrated electrothermal coupling model for each thermal section, avoids conservative capacity expansion decisions under fixed frequencies, thus enabling capacity expansion control under non-standard frequencies and releasing the transmission potential of low-frequency submarine cables. Next, the target operating frequency is sent to the shore-end frequency converter to adjust the submarine cable operating frequency to the target operating frequency. The target transmission current is sent to the transmission system so that the transmission current regulated by the transmission system is less than or equal to the target transmission current, ensuring the safety and effectiveness of low-frequency submarine cable capacity expansion control and improving the transmission capacity of the submarine cable.

[0126] This invention also provides a dynamic capacity expansion device for low-frequency submarine cables. Figure 3 This is a schematic diagram of the structure of a low-frequency submarine cable dynamic capacity expansion device provided in an embodiment of the present invention; as shown. Figure 3 As shown, the above-mentioned device includes:

[0127] Temperature acquisition module 310 is used to collect the conductor temperature distribution along the cable and the seabed ambient temperature through the built-in optical fiber integrated into the low-frequency submarine cable and the external optical fiber laid parallel to the cable, respectively.

[0128] The model update module 320 is used to divide the low-frequency submarine cable into multiple thermal sections according to the burial method of the low-frequency submarine cable; by minimizing the temperature residual function under the current operating conditions and seabed temperature environment, the parameters of the electrothermal coupling model of each thermal section are iteratively updated to obtain the temperature-calibrated electrothermal coupling model of each thermal section; the current operating conditions include the current operating frequency and the current transmission current; the temperature residual function is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature of each thermal section; the predicted conductor hot spot temperature of each thermal section is determined based on the electrothermal coupling model of each thermal section; the actual conductor hot spot temperature of each thermal section is determined based on the conductor temperature distribution along the line.

[0129] The collaborative optimization module 330 is used to collaboratively optimize the operating frequency and the transmission current based on the temperature-calibrated electrothermal coupling model of each thermal section, under target constraints, with the goal of maximizing the transmission power, to obtain the target operating frequency and the target transmission current.

[0130] The capacity expansion module 340 is used to send the target operating frequency to the shore-end frequency converter to adjust the submarine cable operating frequency to the target operating frequency; and to send the target transmission current to the power transmission system so that the submarine cable transmission current adjusted by the power transmission system is less than or equal to the target transmission current.

[0131] This invention also provides an electronic device, which includes a processor and a memory. The memory stores at least one instruction, at least one program, a code set, or an instruction set. The at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to implement the low-frequency submarine cable dynamic capacity expansion method as described in any of the method embodiments.

[0132] Embodiments of the present invention also provide a computer storage medium, which can be disposed in a server to store at least one instruction, at least one program, code set, or instruction set for implementing the method embodiments. The at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to implement the low-frequency submarine cable dynamic capacity expansion method as described in any of the method embodiments.

[0133] Optionally, in embodiments of the present invention, the storage medium may be located at at least one of a plurality of network servers in a computer network. Optionally, in embodiments of the present invention, the storage medium may include, but is not limited to, 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.

[0134] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0135] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more flowcharts and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0136] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more flowcharts and / or boxes Figure 1 The function specified in one or more boxes.

[0137] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more flowcharts and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0138] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0139] Finally, it should be noted that the embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for dynamic capacity expansion of low-frequency submarine cables, characterized in that, The method includes: The conductor temperature distribution along the cable and the seabed ambient temperature are collected by integrating the built-in optical fiber into the low-frequency submarine cable and laying the external optical fiber parallel to the cable. Based on the burial method of the low-frequency submarine cable, the low-frequency submarine cable is divided into multiple thermal sections. By minimizing the temperature residual function under the current operating conditions and seabed temperature environment, the parameters of the electrothermal coupling model for each thermal section are iteratively updated to obtain a temperature-calibrated electrothermal coupling model for each thermal section. The current operating conditions include the current operating frequency and the current transmission current. The temperature residual function is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature for each thermal section. The predicted conductor hot spot temperature for each thermal section is determined based on the electrothermal coupling model for each thermal section. The actual conductor hot spot temperature for each thermal section is determined based on the conductor temperature distribution along the line. Based on the temperature-calibrated electrothermal coupling model of each thermal section, under the target constraint conditions, with the goal of maximizing the transmission power, the operating frequency and transmission current are optimized in a coordinated manner to obtain the target operating frequency and target transmission current. The target operating frequency is sent to the shore-end frequency converter to adjust the submarine cable operating frequency to the target operating frequency; the target transmission current is sent to the power transmission system so that the submarine cable transmission current regulated by the power transmission system is less than or equal to the target transmission current.

2. The method for dynamic capacity expansion of low-frequency submarine cables according to claim 1, characterized in that, The process involves iteratively updating the parameters of the electrothermal coupling model for each thermal section by minimizing the temperature residual function under the current operating conditions and seabed temperature environment, resulting in a temperature-calibrated electrothermal coupling model for each thermal section, including: Based on the current operating conditions and seabed ambient temperature, and using the electrothermal coupling model of each thermal section, the predicted conductor hot spot temperature of each thermal section is determined. The temperature residual of each thermal section is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature of each thermal section. When the temperature residual is greater than the temperature threshold, a temperature residual function is determined based on the temperature residual of each thermal section, as shown in the following formula: ； in, ; in, Represents the temperature residual function; This represents the weight corresponding to the temperature residual of the i-th thermal section; This represents the temperature residual corresponding to the i-th thermal section. This represents the actual conductor hot spot temperature of the i-th thermal section. This represents the predicted conductor hot spot temperature of the i-th thermal section; represents the parameters of the electrothermal coupling model for the i-th thermal section. The initial parameters represent the electrothermal coupling model of the i-th thermal section; Represents the regularization coefficient; The parameters of the electrothermal coupling model for each thermal section are shown in the following equation: ； in, This represents the equivalent external thermal resistance of the seabed corresponding to the i-th thermal section. This represents the correction factor for the sheath circulation loss in the i-th thermal section. This represents the armor circulation loss correction coefficient for the i-th thermal section; By minimizing the temperature residual function, the parameters of the electrothermal coupling model for each thermal section are iteratively updated to obtain a temperature-calibrated electrothermal coupling model for each thermal section.

3. The method for dynamic capacity expansion of low-frequency submarine cables according to claim 2, characterized in that, The step of determining the predicted conductor hotspot temperature for each thermal section based on the current operating conditions and seabed ambient temperature, using an electrothermal coupling model for each thermal section, includes: Based on the current operating conditions and seabed ambient temperature, and using the operating temperature mapping database for each thermal section, the predicted conductor hot spot temperature for each thermal section is determined. The operating temperature mapping database for each thermal section is constructed based on the electrothermal coupling model of each thermal section; the operating temperature mapping database for each thermal section is constructed in the following manner: By scanning the operating parameters of the electrothermal coupling model of each thermal section, the conductor hot spot temperature under the operating parameters of each thermal section is determined; the operating parameters include operating frequency, transmission current, seabed ambient temperature, seabed equivalent thermal resistance, and burial depth. Based on the conductor hot spot temperature under the operating parameters of each thermal section, the mapping relationship between the operating parameters and the conductor hot spot temperature is determined, and the operating temperature mapping database of each thermal section is obtained.

4. The method for dynamic capacity expansion of low-frequency submarine cables according to claim 1, characterized in that, The temperature-calibrated electrothermal coupling model based on each thermal section, under target constraints, aims to maximize the transmission power and collaboratively optimizes the operating frequency and transmission current to obtain the target operating frequency and target transmission current, including: Based on the temperature-calibrated electrothermal coupling model of each thermal section, the predicted conductor hot spot temperature of each thermal section is determined; The target constraint conditions are defined as follows: the predicted conductor hot spot temperature of each thermal section is less than or equal to the maximum allowable conductor temperature, and the converter capacity is less than or equal to the capacity threshold. The objective function is to maximize the transmission power, as shown in the following equation: ； in, Indicates the transmission power. Indicates the current operating frequency. Indicates the current being transmitted; Indicates line voltage. Indicates the operating frequency is And the transmission current is The power factor corresponding to the time; Based on the temperature-calibrated electrothermal coupling model of each thermal section, under the target constraints, the operating frequency and the transmission current are optimized in conjunction with the objective function to obtain the target operating frequency and the target transmission current.

5. The method for dynamic capacity expansion of low-frequency submarine cables according to claim 1, characterized in that, The method further includes: Based on the target transmission current, determine the maximum safe transmission power at the target operating frequency; The maximum safe transmission power is sent to the power transmission system so that the power transmission system adjusts the transmission power according to a preset ramp rate when the conductor hot spot temperature is lower than the difference between the conductor's maximum allowable temperature and temperature margin; wherein the adjusted actual transmission power is less than the maximum safe transmission power.

6. The method for dynamic capacity expansion of low-frequency submarine cables according to claim 1, characterized in that, The parameters of the electrothermal coupling model for each thermal section are iteratively updated using the least squares method or the extended Kalman filter method.

7. A dynamic capacity expansion system for low-frequency submarine cables, characterized in that, The system includes: a distributed optical fiber temperature measurement device, a control device, a power transmission system, and a shore-end frequency converter. The distributed optical fiber temperature measurement device is connected to the built-in optical fiber of the low-frequency submarine cable and the external optical fiber of the low-frequency submarine cable, respectively. The control device is connected to the distributed optical fiber temperature measurement device, the power transmission system is connected to the control device, and the shore-end frequency converter is connected to the control device. The distributed optical fiber temperature measurement device is used to receive a first optical fiber output signal transmitted by the built-in optical fiber integrated in the low-frequency submarine cable to determine the conductor temperature distribution along the line; and to receive a second optical fiber output signal transmitted by an external optical fiber laid parallel to the cable to determine the seabed ambient temperature. The control device is used to receive the conductor temperature distribution along the line and the seabed ambient temperature sent by the distributed optical fiber temperature measurement device, and to execute the low-frequency submarine cable dynamic capacity expansion method as described in any one of claims 1-6 to generate the target operating frequency and the target transmission current. The shore-end frequency converter is used to receive the target operating frequency sent by the control device and adjust the submarine cable operating frequency to the target operating frequency; The power transmission system is used to receive the target transmission current sent by the control device and adjust the submarine cable transmission current so that the submarine cable transmission current is less than or equal to the target transmission current.

8. A dynamic capacity expansion device for low-frequency submarine cables, characterized in that, The device includes: The temperature acquisition module is used to collect the conductor temperature distribution along the cable and the seabed ambient temperature through the built-in optical fiber integrated into the low-frequency submarine cable and the external optical fiber laid parallel to the cable, respectively. The model update module is used to divide the low-frequency submarine cable into multiple thermal sections according to the burial method of the low-frequency submarine cable; by minimizing the temperature residual function under the current operating conditions and seabed temperature environment, the parameters of the electrothermal coupling model of each thermal section are iteratively updated to obtain the temperature-calibrated electrothermal coupling model of each thermal section; the current operating conditions include the current operating frequency and the current transmission current; the temperature residual function is determined based on the predicted conductor hot spot temperature and the actual conductor hot spot temperature of each thermal section; the predicted conductor hot spot temperature of each thermal section is determined based on the electrothermal coupling model of each thermal section; the actual conductor hot spot temperature of each thermal section is determined based on the conductor temperature distribution along the line. The collaborative optimization module is used to collaboratively optimize the operating frequency and the transmission current based on the temperature-calibrated electrothermal coupling model of each thermal section, under target constraints, with the goal of maximizing the transmission power, to obtain the target operating frequency and the target transmission current. The capacity expansion module is used to send the target operating frequency to the shore-end frequency converter to adjust the submarine cable operating frequency to the target operating frequency; and to send the target transmission current to the power transmission system so that the submarine cable transmission current adjusted by the power transmission system is less than or equal to the target transmission current.

9. An electronic device comprising a processor and a memory, the memory storing at least one instruction and at least one program, the at least one instruction and the at least one program being loaded and executed by the processor to implement the low-frequency submarine cable dynamic capacity expansion method as described in any one of claims 1 to 6.

10. A computer storage medium storing at least one instruction and at least one program, wherein the at least one instruction and the at least one program are loaded and executed by a processor to implement the low-frequency submarine cable dynamic capacity expansion method as described in any one of claims 1 to 6.

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