Submarine cable corrosion calculation method based on ocean direct current grounding electrode and related product

Abstract

The embodiment of the invention relates to the field of electrical engineering, and provides a submarine cable corrosion calculation method based on an ocean direct current grounding electrode and a related product, and the method comprises the steps: obtaining a calculation model of an armor layer affected by the ocean direct current grounding electrode; according to the soil layering model, the grounding electrode model and the cable model, electromagnetic field distribution conditions of the armor layer and the sheath layer are obtained through calculation; analyzing the influence of the submarine cable length of the submarine cable, the electrode distance between the submarine cable and the ocean direct-current grounding electrode and the end part distance between the ocean direct-current grounding electrode and the submarine cable end part on the electromagnetic field distribution condition to obtain an electromagnetic field distribution change result; and determining the corrosion condition of the armor layer according to the electromagnetic field distribution change result. According to the embodiment of the invention, the method can achieve the analysis and calculation of a brand-new strategy of the impact on the nearby submarine cable from the DC current under the condition of the monopole ground operation of the ocean DC grounding electrode, and facilitates the solving of the problem of the fracture and damage of the armor layer under the impact of an external environment when the DC current of the ocean DC grounding electrode flows into the armor layer.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of electrical engineering, and in particular to a method for calculating submarine cable corrosion based on a marine DC grounding electrode and related products. Background Art

[0002] Submarine cables (or submarine cables) serve as channels for transmitting electricity across the ocean, often connecting power systems on land and on islands. With the rapid development of offshore wind power, the use of submarine cables has increased. For example, offshore wind power generation primarily uses collection cables to transmit electricity from wind turbines to offshore booster stations. After the voltage is increased, it is then transmitted to onshore control centers via transmission cables.

[0003] Marine DC grounding electrodes are commonly used in high-voltage direct current transmission systems. As part of the current return path, they can be installed in marine environments, such as the seabed. Current flows through the marine DC grounding electrodes into the seawater or seabed strata, forming a closed loop. Because marine DC grounding electrodes are exposed to seawater for long periods of time, their metal components are prone to corrosion, affecting their lifespan and safety. Nearby submarine cables are also affected by the DC grounding electrodes and face corrosion risks. When the DC current from the marine DC grounding electrode flows into the armor layer, it accelerates the corrosion of the armor layer, ultimately weakening the armor layer locally and causing the armor layer to break and break under the influence of the external environment, posing a hidden danger to the safe operation of the submarine cable. Summary of the Invention

[0004] The embodiments of the present application provide a submarine cable corrosion calculation method and related products based on a marine DC grounding electrode, which can perform a new strategy for analyzing and calculating the impact of the DC current of the marine DC grounding electrode on nearby submarine cables when the DC current is in single-pole operation. This helps to solve the problem that the DC current of the marine DC grounding electrode accelerates the corrosion of the armor layer when flowing into the armor layer, resulting in breakage and damage of the armor layer under the influence of the external environment.

[0005] In one aspect, an embodiment of the present application provides a method for calculating corrosion of a submarine cable based on a marine DC grounding electrode. In a preset simulation software, grounding rods are provided at the grounding ends of the submarine cable, and the grounding rods are connected to the armor layer and the sheath layer of the submarine cable. The method includes:

[0006] Obtaining a calculation model of the effect of the marine DC grounding electrode on the armor layer; the calculation model is constructed based on a soil layer model, a grounding electrode model, and a cable model;

[0007] Calculating the electromagnetic field distribution of the armor layer and the sheath layer according to the soil layer model, the ground electrode model and the cable model;

[0008] Analyzing the effects of the length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution, and obtaining a result of the change in the electromagnetic field distribution;

[0009] The corrosion condition of the armor layer is determined according to the change result of the electromagnetic field distribution.

[0010] On the other hand, an embodiment of the present application provides a submarine cable corrosion calculation device based on a marine DC grounding electrode. In a preset simulation software, grounding rods are provided at the grounding ends of the submarine cable, and the grounding rods are connected to the armor layer and the sheath layer of the submarine cable. The device includes:

[0011] A calculation model acquisition module is used to obtain a calculation model of the impact of the marine DC grounding electrode on the armor layer; the calculation model is constructed based on a soil layer model, a grounding electrode model, and a cable model;

[0012] an electromagnetic field distribution generating module, configured to calculate the electromagnetic field distribution of the armor layer and the sheath layer according to the soil layer model, the ground electrode model, and the cable model;

[0013] a distribution change result generating module, configured to analyze the effects of the length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution, and obtain an electromagnetic field distribution change result;

[0014] The corrosion condition determination module is used to determine the corrosion condition of the armor layer according to the change result of the electromagnetic field distribution.

[0015] On the other hand, an embodiment of the present application also provides an electronic device, comprising: a processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein when the computer program is executed by the processor, any one of the methods for calculating submarine cable corrosion based on marine DC grounding electrodes is implemented.

[0016] On the other hand, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, any one of the methods for calculating submarine cable corrosion based on marine DC grounding electrodes is implemented.

[0017] On the other hand, an embodiment of the present application further provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the submarine cable corrosion calculation method based on the marine DC grounding electrode described in the above aspects.

[0018] The embodiments of the present application provide a method for calculating corrosion of submarine cables based on marine DC grounding electrodes and related products. In the preset simulation software, after the submarine cable is grounded, the current of the marine DC grounding electrode can flow into the sheath layer of the submarine cable and into the armor layer of the submarine cable through the sheath layer, that is, the marine DC grounding electrode affects the armor layer of the submarine cable. At this time, a calculation model of the influence of the marine DC grounding electrode on the armor layer can be obtained. The calculation model is constructed based on the soil stratification model, the grounding electrode model and the cable model. At this time, the electromagnetic field distribution of the armor layer and the sheath layer under the influence of the marine DC grounding electrode can be calculated based on the above-mentioned model, and the influence of the cable length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution is analyzed to obtain the electromagnetic field distribution change result, and then the corrosion condition of the armor layer is determined according to the electromagnetic field distribution change. The electromagnetic field distribution on the armor and sheath of the submarine cable when the marine DC grounding electrode is in operation is calculated through a computational model. Based on an analysis of multiple factors affecting the electromagnetic field distribution of the submarine cable, the corrosion of the armor layer is evaluated based on the results of the electromagnetic field distribution changes. This can achieve a new strategy for analyzing and calculating the impact of the DC current on the nearby submarine cables when the marine DC grounding electrode is in single-pole operation. This helps to solve the problem of the DC current of the marine DC grounding electrode accelerating the corrosion of the armor layer when it flows into the armor layer, leading to breakage and damage of the armor layer under the influence of the external environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flowchart of the steps of a method for calculating submarine cable corrosion based on a marine DC grounding electrode provided in an embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of the operating interface of the preset simulation software provided in the embodiment of the present application;

[0021] Figure 3 Schematic diagram of calculation of armored steel wire mass per unit area provided in the embodiment of the present application;

[0022] Figures 4A to 4B Schematic diagram of the calculation model provided in the embodiment of the present application;

[0023] 5A to 5D Schematic diagram of current distribution of a three-phase single-core submarine cable provided in an embodiment of the present application;

[0024] 6A to 6D Schematic diagram of the potential distribution of a three-phase single-core submarine cable provided in an embodiment of the present application;

[0025] 7A to 7B Schematic diagram of leakage current density distribution of a three-phase single-core submarine cable provided in an embodiment of the present application;

[0026] Figure 8 Schematic diagram of current distribution of a three-core submarine cable provided in an embodiment of the present application;

[0027] Figure 9 Schematic diagram of the potential distribution of a three-core submarine cable provided in an embodiment of the present application;

[0028] Figure 10 Schematic diagram of the leakage current density distribution of the three-core submarine cable provided in an embodiment of the present application;

[0029] Figures 11A to 11C This is a schematic diagram of the distribution change of the electromagnetic field distribution affected by the length of the submarine cable provided in an embodiment of the present application;

[0030] 12A to 12C This is a schematic diagram of the distribution change results of the electromagnetic field distribution affected by the electrode distance provided in the embodiment of the present application;

[0031] 13A to 13C This is a schematic diagram of the distribution change results of the electromagnetic field distribution affected by the end distance provided in the embodiment of the present application;

[0032] Figure 14 This is a structural block diagram of a submarine cable corrosion calculation device based on a marine DC grounding electrode according to an embodiment of the present application;

[0033] Figure 15 This is a structural block diagram of an electronic device provided in an embodiment of the present application;

[0034] Figure 16 This is a structural block diagram of a computer-readable storage medium provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0036] The main structure of a submarine cable, from the inside out, can be divided into the core, insulation layer, lead sheath, filling layer, armor layer, and outer layer. The outer layer is made of nylon, which is not water-resistant. The water-blocking tape on the outside of the lead sheath does block water, preventing the lead sheath from coming into contact with seawater.

[0037] Specifically, seawater can penetrate the outer sheath into the filler layer, where the armored steel wires come into contact with the highly conductive seawater, achieving full grounding. Furthermore, because the armored cables at both ends of the submarine cable are directly grounded in parallel with the lead sheath, DC current flows from the submarine cable's grounding point into the lead sheath. If the marine DC grounding electrode is close to the submarine cable, its DC current flows through the highly conductive seawater into the nearby cable's armored layer, where it is then dispersed through the even more conductive armored steel wires.

[0038] However, when the DC current of the marine DC grounding electrode flows into the armor layer, it will accelerate the corrosion of the armor layer, eventually weakening the local armor layer and causing the armor layer to break and break under the influence of the external environment, posing a hidden danger to the safe operation of the submarine cable.

[0039] The embodiments of the present application can implement a new strategy for analyzing and calculating the impact of the DC current of the marine DC grounding electrode on the nearby submarine cable when the DC current is in single-pole operation, which helps to solve the problem that the DC current of the marine DC grounding electrode accelerates the corrosion of the armor layer when flowing into the armor layer, resulting in breakage and damage of the armor layer under the influence of the external environment.

[0040] Reference Figure 1 , shows a flowchart of the steps of a method for calculating submarine cable corrosion based on a marine DC grounding electrode provided by an embodiment of the present application, which may specifically include the following steps:

[0041] Step S101: obtaining a calculation model of the impact of the marine DC grounding electrode on the armor layer.

[0042] In an embodiment of the present application, grounding rods can be provided at the grounding ends of both ends of the submarine cable in the preset simulation software, and the provided grounding rods are connected to the armor layer and sheath layer of the submarine cable, so that after the submarine cable is grounded, the current of the marine DC grounding electrode can flow from the marine DC grounding electrode into the sheath layer of the submarine cable, and flow into the armor layer of the submarine cable through the sheath layer, so that there is an electromagnetic field distribution in the armor layer and sheath layer of the submarine cable, such as current distribution, potential distribution and leakage current density distribution.

[0043] For example, the preset simulation software may be CDEGS (Current Distribution, Electromagnetic Field, Grounding and Soil Structure Analysis) grounding software. The connection function in the CDEGS grounding software may be implemented as follows: Figure 2As shown, the connection function can define the electrical connection between conductors. When there is no conductor in space, taking the three-phase single-core submarine cable as an example, the sheath layer and armor layer of the three-phase single-core submarine cable can be selected separately and connected to the set grounding rods, thereby achieving grounding at both ends of the submarine cable.

[0044] In some embodiments of the present application, the impact of the DC current of the marine DC grounding electrode on the nearby submarine cable is due to the outer layer of the submarine cable being made of nylon material, which is not water-resistant, and the water-blocking tape outside the lead sheath is water-resistant, so that the lead sheath layer does not come into contact with seawater. In order to simplify the calculation model, the specific consideration is the impact of the marine DC grounding electrode on the submarine armored steel wire, that is, the calculation model of the impact of the marine DC grounding electrode on the armor layer can be specifically obtained.

[0045] Step S102 : calculating the electromagnetic field distribution of the armor layer and the sheath layer according to the soil layer model, the ground electrode model and the cable model.

[0046] In practical applications, the calculation model can calculate the electromagnetic field distribution on the armor layer of the submarine cable when the marine DC grounding electrode is in operation. Since the two ends of the sheath layer are connected in parallel with the armor layer when the submarine cable is grounded in the preset simulation software, there is a phenomenon that DC current flows into the sheath layer from the parallel grounding point. At this time, the calculation model can also be used to calculate the electromagnetic field distribution on the sheath layer.

[0047] Optionally, there are multiple factors that can affect the electromagnetic field distribution of the submarine cable. For example, the distribution of the current entering the sea will affect the electromagnetic field distribution of the submarine cable, and thus affect the magnitude of the current flowing into and out of the armor; different injection distances will affect the distribution of current in the submarine cable; the electrical characteristic parameters will affect the resistance in the calculation model. Although it has no effect on the change in the electromagnetic field distribution, it will affect the specific value of the electromagnetic field distribution in the submarine cable.

[0048] In some embodiments of the present application, the calculation model used can combine models corresponding to multiple influencing factors, so that when the calculation model calculates the electromagnetic field distribution, the obtained electromagnetic field distribution is the distribution obtained after considering multiple influencing factors, which can ensure the accuracy of the obtained electromagnetic field distribution.

[0049] Specifically, the calculation model can be constructed based on a soil layer model, a ground electrode model, and a cable model. The soil layer model can be used to indicate the distribution of current entering the sea. The ground electrode model is used to direct the current from the marine DC ground electrode into the sea, specifically indicating the injection distance for the submarine cable. The cable model can be used to indicate the electrical characteristic parameters of the armor and sheath layers, which will affect the resistance in the calculation model.

[0050] Optionally, the electromagnetic field distribution to be calculated may include current distribution, potential distribution and leakage current density distribution. In some embodiments of the present application, the current distribution, potential distribution and leakage current density distribution of the armor layer and the sheath layer can be calculated based on the sea-entry current, injection distance and electrical characteristic parameters through a calculation model. It should be noted that the specific calculation process can be implemented through the calculation model built into the preset simulation software, which can be specifically expressed as inputting the above parameters into the calculation model of the preset simulation software, and directly outputting the electromagnetic field distribution of the armor layer and the sheath layer. The embodiments of the present application do not limit the specific calculation process.

[0051] Illustratively, the current distribution of the armor layer can be presented as the current at the grounding point close to the marine DC grounding electrode being greater than the current at other positions; the potential distribution of the armor layer can be presented as the potential decreasing from the center position of the marine DC grounding electrode to both ends; the leakage current density distribution of the armor layer can be presented as the leakage current density at the grounding point close to the marine DC grounding electrode being greater than the leakage current density on both sides of the grounding point, and the leakage current density at the center position of the marine DC grounding electrode being less than the leakage current density at both ends.

[0052] The current distribution of the sheath layer can be presented as equal current at all positions; the potential distribution of the sheath layer can be presented as the potential decreasing from the end close to the marine DC grounding electrode to the end farthest from the marine DC grounding electrode; the leakage current density distribution of the sheath layer can be presented as the leakage current density at all positions being 0.

[0053] In the embodiment of the present application, the above-mentioned electromagnetic field distribution is helpful for understanding the distribution of current, potential and leakage current density at various positions on the submarine cable, and thus is helpful for determining the corrosion condition of the submarine cable.

[0054] Step S103: Analyze the effects of the length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution to obtain the electromagnetic field distribution change result.

[0055] In some embodiments of the present application, multiple factors affecting the electromagnetic field distribution of the submarine cable can be further analyzed, and then the corrosion condition of the armor layer can be evaluated based on the results of the electromagnetic field distribution changes to ensure the accuracy of the submarine cable corrosion assessment.

[0056] Optionally, multiple factors influencing the electromagnetic field distribution of a submarine cable may include, but are not limited to, the cable length, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable. Specifically, different cable lengths, electrode distances, and end distances may be set in pre-set simulation software to obtain different electromagnetic field distribution results.

[0057] Exemplarily, the effect of the length of the submarine cable on the distribution of the electromagnetic field, as an example, the effect of the length of the submarine cable on the current distribution can be presented as the current at one end away from the ocean DC grounding electrode is positively correlated with the length of the submarine cable, that is, the current at one end away from the ocean DC grounding electrode increases with the increase of the length of the submarine cable; as another example, the effect of the length of the submarine cable on the potential distribution can be presented as the potential at one end away from the ocean DC grounding electrode is negatively correlated with the length of the submarine cable, that is, the potential at one end away from the ocean DC grounding electrode decreases with the increase of the length of the submarine cable; as another example, the effect of the length of the submarine cable on the distribution of the leakage current density can be presented as the increase of the leakage current density at both ends is negatively correlated with the length of the submarine cable, that is, the rising trend of the local rise at both ends of the submarine cable becomes slow with the increase of the length of the submarine cable.

[0058] The influence of electrode distance on the electromagnetic field distribution can be shown as the current, potential and leakage current density of the armor layer are negatively correlated with the electrode distance, that is, the closer the electrode distance is, the greater the current, potential and leakage current density of the armor layer.

[0059] The influence of the end distance on the electromagnetic field distribution can be shown as the current, potential and leakage current density of the armor layer are negatively correlated with the end distance, that is, the closer the end distance is, the peak current of the armor layer appears.

[0060] Based on the above results of electromagnetic field distribution changes, it is helpful to evaluate the corrosion of submarine cables under specific working conditions, such as maximum leakage current density.

[0061] Step S104: determining the corrosion condition of the armor layer according to the result of the change in the electromagnetic field distribution.

[0062] Specifically, when the marine DC grounding electrode operates as a cathode, current can flow from the armor layer into the armor wire, which is susceptible to corrosion, necessitating calculation of the corrosion status. Given that the leakage current density exhibits a peak in the aforementioned electromagnetic field distribution change results, embodiments of the present application can determine the corrosion status at a specific leakage current density (typically the maximum leakage current density) to assess the location of the most severely corroded area in the armor layer.

[0063] The corrosion conditions that need to be determined may include the corrosion severity of the armor layer and the service life of the armor layer, wherein the corrosion severity can be evaluated based on an indicator of corrosion depth, and the service life can be evaluated based on an indicator of corrosion rate.

[0064] Optionally, power-on data can be obtained based on the results of the electromagnetic field distribution change, and then the corrosion depth and corrosion rate under a specific leakage current density can be calculated based on the power-on data.

[0065] In actual applications, the armor layer of the submarine cable and the armored steel wire in the armor layer are made of metal. The amount of corrosion at the anode of the metal when power is applied conforms to Faraday's law. That is, Faraday's law can be used to calculate the corrosion rate and corrosion depth under the maximum leakage current density using parameters such as current and operating time (for example, 5 hours per year) obtained in the preset simulation software, thereby determining the corrosion severity and service life of the armor layer.

[0066] Specifically, the power-on data under a specific leakage current density obtained from the results of the change in the electromagnetic field distribution may include the current intensity, power-on time, electron transfer number and metal atomic mass under the specific leakage current density. At this time, Faraday's law may be used to calculate the amount of corrosion under the specific leakage current density based on the current intensity, power-on time, electron transfer number and metal atomic mass under the specific leakage current density, as well as the Faraday constant. Then, based on the amount of corrosion under the specific leakage current density, the corrosion depth and corrosion area under the specific leakage current density may be obtained. Based on the corrosion area, the current intensity, electron transfer number and metal atomic mass under the specific leakage current density, and the Faraday constant, the corrosion rate under the specific leakage current density may be calculated, thereby realizing an assessment of the severity of corrosion and service life of the armor layer. Based on the aforementioned assessment results, the armor layer may be replaced or otherwise treated before it breaks or is damaged, thereby ensuring the safe operation of the submarine cable.

[0067] For example, Faraday's law can be expressed as follows:

[0068] (Formula 1)

[0069] In Formula 1, W is the corrosion amount; Q is the amount of current flowing; M is the atomic mass of the metal; n is the number of electron transfers; F is the Faraday constant, which is 9.65×10000C / mol; I is the current intensity; and t is the duration of the current flow. The amount of current flowing Q, the current intensity I, the duration of the current flow t, the atomic mass of the metal M, and the number of electron transfers n can be obtained from the current distribution data, potential distribution data, and leakage current density distribution data in the electromagnetic field distribution change results, and this embodiment of the application is not limited to this.

[0070] The above formula of Faraday's law can be transformed into the following formula:

[0071] (Equation 2)

[0072] The resulting formula can be used to calculate the corrosion rate of the armor layer. In Formula 2, V is the corrosion rate in g / (m2·h); S is the corrosion area; t is the power-on time; I is the current intensity; n is the number of electron transfers; and F is the Faraday constant.

[0073] The overall corrosion of the armor layer is mainly affected by external environmental factors, while the armor steel wire has internal corrosion, which is mainly caused by the close contact between the steel wires forming gaps and retaining electrolytes (such as seawater) causing corrosion.

[0074] The present embodiment further evaluates the corrosion of the armored steel wires. The corrosion of the armored steel wires within the armor layer can be determined by referring to the following analysis and calculation process.

[0075] First, the corrosion rate of the armor steel wire can be calculated to evaluate the service life of the armor steel wire.

[0076] Specifically, for steel wire corrosion, an electrochemical reaction will occur under the combined action of water and air, which can release electrons at the anode steel wire: , In a corrosive environment, electrons continuously flow from the anode to the cathode of the electrolytic cell to generate current, which easily forms an iron hydroxide film on the surface of the steel wire, combining with water and oxygen to form iron hydroxide: , , that is, the steel wire produces an oxygen absorption reaction in the actual environment; and when the chloride ion solution is used as the electrolyte, it will accelerate the electrochemical corrosion, and its main corrosion equation is: , , that is, the steel wire will produce hydrogen evolution reaction. The two reactions produced by the aforementioned steel wire will cause steel wire corrosion, but it is usually manifested as corrosion caused by the steel wire's oxygen absorption reaction (abbreviated as oxygen absorption corrosion).

[0077] For oxygen absorption corrosion of steel wire, the number of transferred electrons n is 2; the corrosion current density is the calculated leakage current density; the metal atomic mass M of iron is 56; the Faraday constant is 9.65×10000C / moL. At this time, the above data can be substituted into the above formula 2 to calculate the corrosion rate of the armored steel wire, which can be used to indicate the service life of the armored steel wire.

[0078] As well, the severity of corrosion of the armor wires can be assessed.

[0079] Specifically, the corrosion mass of the armored steel wire per unit area can be calculated. The total mass of the armored steel wire per unit area (in g) can be calculated as follows: Figure 3 As shown in FIG, multiple armored steel wires can be equivalent to cylindrical steel pipes for calculation. For example, assuming that the outer radius r of the steel wire layer is out The value of can be 6.415cm, the inner radius r of the steel wire layer in The value of can be 5.815cm, the value of steel wire density ρ can be 7.85g / cm3, and the corrosion mass G of armored steel wire per unit area can be calculated by the following formula 3:

[0080] (Formula 3)

[0081] In formula 3, S can be Figure 3 The cross-sectional area of ​​the armored steel wire shown is a known value. After calculating the corrosion mass G and the aforementioned corrosion rate V, the time required to completely corrode a steel wire layer of a fixed thickness, as well as the ratio of the armored steel wire's corrosion mass to the total steel wire mass per unit time, can be calculated. This allows the corrosion volume of the armored steel wire to be assessed, allowing the severity of the armored steel wire corrosion to be assessed. Based on these assessment results, the armored steel wire can be replaced before it breaks or breaks, ensuring the safe operation of the submarine cable.

[0082] In some embodiments of the present application, the submarine cables evaluated in the embodiments of the present application may include three-phase single-core submarine cables and three-core submarine cables. In order for those skilled in the art to further understand the submarine cable corrosion calculation method based on marine DC grounding electrodes provided in the embodiments of the present application, the following examples are used for illustration:

[0083] In this example, CDEGS grounding software can be used to establish a calculation model of the impact of marine DC grounding electrodes on 220kV three-phase single-core submarine cables and three-core submarine cables. This can be used to calculate the current distribution, potential distribution, and leakage current density distribution on the armor and sheath layers of the three-phase single-core submarine cables and three-core submarine cables when the marine DC grounding electrode is in operation.

[0084] Optionally, the size of the marine DC grounding electrode can be two linear electrodes with a length of 300m. In the example, the marine DC grounding electrode is directly laid on the seabed at a depth of 10m; the size of the submarine cable can be 500mm 2 220kV single-core AC submarine cable with a cross-sectional area of ​​500mm 2 The cross-sectional area of ​​a 220kV three-core AC submarine cable. Its material and geometric parameters can be shown in Tables 1 and 2 below:

[0085] Table 1 AC 220kV single-core submarine cable (500mm 2 ) material and geometric parameters

[0086]

[0087] Table 2 AC 220kV three-core submarine cable (500mm 2 ) material and geometric parameters

[0088]

[0089] As can be seen from Tables 1 and 2 above, since the outer layer is made of PP rope, i.e. nylon material, which is not water-resistant, the water-blocking tape outside the lead sheath has water-blocking ability, so that the lead sheath layer does not come into contact with seawater. In order to simplify the calculation model, the specific consideration is the impact of the marine DC grounding electrode on the submarine armored steel wire, that is, the calculation model of the impact of the marine DC grounding electrode on the armor layer can be specifically obtained. That is, at this time, the CDEGS calculation model of the three-phase single-core submarine cable and the marine DC grounding electrode can be established respectively (such as Figure 4A As shown in ), and the CDEGS calculation model of the three-core submarine cable and the marine DC grounding electrode (as shown in Figure 4B shown).

[0090] In such Figure 4A and Figure 4B In the example model shown, the vertical distance between the marine DC grounding electrode and the submarine cable is 50 meters, and the distance between the left end of the marine DC grounding electrode and the grounding point on the left side of the 220kV submarine cable is 150 meters. The marine DC grounding electrode has a rated injection current of 1000A. In this case, the established calculation model can be used to calculate the armor layer, specifically the current distribution, potential distribution, and leakage current density distribution along the armor wires.

[0091] Optionally, the distribution of the current entering the sea will affect the electromagnetic field distribution of the submarine cable, and thus affect the magnitude of the current flowing into and out of the armor; different injection distances will affect the distribution of the current in the submarine cable; the electrical characteristic parameters will affect the resistance in the calculation model, and will affect the specific value of the electromagnetic field distribution in the submarine cable. Specifically, the calculation model can be constructed based on the soil stratification model, the grounding electrode model, and the cable model. Among them, the soil stratification model can be used to indicate the distribution of the current entering the sea; the function of the grounding electrode model is to direct the current of the marine DC grounding electrode into the sea, and it can be used to indicate the injection distance for the submarine cable; the cable model can be used to indicate the electrical characteristic parameters of the armor layer and the sheath layer, and the set electrical characteristic parameters will affect the resistance in the calculation model.

[0092] The specific calculation process can be achieved through the built-in calculation model of the CDEGS grounding software. Specifically, the above parameters are input into the calculation model of the CDEGS grounding software, and the electromagnetic field distribution of the armor layer and the sheath layer is directly output.

[0093] In this example, the input of the above parameters can be expressed as the setting of cable geometric parameters and electrical characteristic parameters in the CDEGS grounding software. Specifically, it can be expressed as setting the relevant parameters of single-core submarine cables and three-core submarine cables through the CDEGS cable module, such as considering the geometric and electrical characteristics of the core wire, insulation layer, sheath layer, filling layer, armor layer, and outer sheath layer, so as to input the relevant parameters into the setting bar to realize the setting of the cable, and then realize the calculation of the electromagnetic field distribution on the armor layer and sheath layer of the corresponding cable. For example, the armored steel wire of the armor layer can be regarded as a pipe, and the outer layer can be regarded as its coating, and the corresponding electrical characteristic parameters can be set. The set electrical characteristic parameters can include resistivity and relative magnetic permeability. For details, please refer to the following Table 3:

[0094] Table 3 Electrical characteristics of steel wire and outer layer

[0095]

[0096] For example, the soil layer model in the calculation model can be a three-layer model, where the layers can include air, seawater, and seabed, respectively. The electrical characteristic parameters of each layer can include resistivity, relative permittivity, and relative magnetic permeability. The thickness and electrical characteristic parameters of each layer can be shown in Table 4 below:

[0097] Table 4 Soil stratification model

[0098]

[0099] In the calculation process of electromagnetic field distribution, the soil stratification model will affect the distribution of current entering the sea, thereby affecting the magnitude of current flowing into and out of the armor layer.

[0100] In this example, the electromagnetic field distribution of the armor layer and sheath layer is output through the calculation model built into the CDEGS grounding software.

[0101] For a single three-phase single-core submarine cable, the current distribution can be as follows: 5A to 5D As shown. Among them, Figure 5A The current distribution on the core, sheath and armor layer of phase A submarine cable; Figure 5B The current distribution on the armor layer of the ABC three-phase submarine cable; Figure 5C The current distribution on the ABC three-phase lead sheath; Figure 5D The current distribution on the core of the ABC three-phase submarine cable is shown in Figure 1. The green dotted line indicates the center position of the marine DC grounding electrode pair.

[0102] like 5A to 5DAs shown in the figure, the current distribution of the armor layer shows that the current at the grounding point close to the marine DC grounding electrode is larger than the current at other locations; the current distribution of the sheath layer shows that the current at each location is equal. Figure 5D As shown in the figure, the current on the core wire of the three-phase submarine cable is close to 0. Since the core wire does not participate in grounding, the DC current of the marine DC grounding electrode cannot flow into the core wire of the three-phase submarine cable; Figure 5C As shown in Figure 1, the DC current of the lead sheath is about 8.4A. The current on the sheath layer of the three-phase submarine cable is similar. This is because the DC current can only flow into the sheath layer from the grounding points at both ends. The three-phase sheath layers are in parallel, so the currents are equal. Figure 5B As shown in the figure, the current distribution on the armor layer of the three-phase submarine cable is quite different. Since the armor layer is in contact with the seawater to achieve full line grounding, the DC current of the marine DC grounding electrode flows from the position of the submarine cable closest to the marine DC grounding electrode into the armor layer of the submarine cable and flows to both sides. The current of phase A cable closest to the marine DC grounding electrode is the largest, followed by phases B and C.

[0103] The submarine cable will generate a DC potential due to the inflow of DC current from the marine DC grounding electrode.

[0104] For a single three-phase single-core submarine cable, its potential distribution can be as follows: 6A to 6D As shown. Among them, Figure 6A The potential distribution on the core, sheath and armor of phase A submarine cable; Figure 6B The potential distribution on the ABC three-phase core line; Figure 6C The potential distribution on the lead sheath of the ABC three-phase submarine cable; Figure 6D The potential distribution on the armor layer of the ABC three-phase submarine cable is shown in Figure 1. The green dotted line indicates the center position of the marine DC grounding electrode pair.

[0105] like 6A to 6D As shown in the figure, the potential distribution of the armor layer shows that the potential decreases from the center position of the marine DC grounding electrode to both ends; the potential distribution of the sheath layer shows that the potential decreases from the end close to the marine DC grounding electrode to the end far away from the marine DC grounding electrode. Figure 6B and Figure 6C As shown in Figure 2, the potential distribution of each phase on the sheath and core of the three-phase single-core submarine cable is relatively consistent; Figure 6D As shown in the figure, there are large differences in the potential distribution on the armor layer. Specifically, the potential of phase A close to the marine DC grounding electrode is higher, followed by phase BC. Moreover, the potential in the middle of the marine DC grounding electrode is the highest and gradually decreases towards the two ends of the submarine cable.

[0106] The submarine cable will generate leakage current density due to the influx of DC current from the marine DC grounding electrode.

[0107] For a single three-phase single-core submarine cable, its potential distribution can be as follows: 7A to 7B As shown. Among them, Figure 7A The leakage current density distribution on the core, sheath and armor of phase A submarine cable; Figure 7B The leakage current density distribution on the armor layer of the ABC three-phase submarine cable is shown in Figure 1. The green dotted line indicates the center position of the marine DC grounding electrode pair.

[0108] like 7A to 7B As shown, the leakage current density distribution of the armor layer shows that the leakage current density at the grounding point near the marine DC grounding electrode is greater than the leakage current density on both sides of the grounding point, and the leakage current density at the center of the marine DC grounding electrode is less than the leakage current density at the ends. The leakage current density distribution of the sheath layer shows that the leakage current density at all locations is 0. Specifically, because the core wire is surrounded by an insulating layer on the outside, the sheath is surrounded by an insulating layer on the inside, and the sheath is surrounded by a waterproof wrapping tape on the outside, no leakage current flows into these two layers of metal conductors. The armor layer is directly in contact with seawater, achieving full grounding. Therefore, the leakage current density on the core wire and armor of the three-phase single-core submarine cable is 0. The DC current of the marine DC grounding electrode flows through the armor layer, generating a large leakage current density on the armor layer. The overall distribution shows that the leakage current density is the largest near the marine DC grounding electrode and gradually decreases towards the sides. The leakage current density at the center of the marine grounding electrode is smaller than that near the ends of the marine DC grounding electrode. This is due to the end effect of the marine DC grounding electrode. Among them, phase A is closest to the marine DC grounding electrode, and the leakage current density of phase A is the largest, followed by phase BC.

[0109] Due to the three-phase symmetry of a three-core submarine cable, the current distribution, potential distribution, and leakage current density distribution of each phase's core, sheath, and armor are identical. Alternatively, in the electromagnetic field distribution, the distribution of one phase, such as phase A, can be analyzed.

[0110] For example, the current distribution of a three-core submarine cable can be as follows: Figure 8 As shown, the maximum DC current flowing through the armor layer can reach nearly 400A. Compared to the calculated results for a three-phase single-core submarine cable, the maximum current flowing through the armor layer increases by nearly three times. This is partly due to the current diversion between the three armor layers of the single-core submarine cable. Furthermore, the larger outer diameter of the three-core submarine cable, and therefore the larger outer diameter of its armor layer, facilitates current conduction compared to a single-core cable. Therefore, the current distribution in a three-core submarine cable is more severe than that in a single-core cable.

[0111] The potential distribution of the three-core submarine cable can be as follows Figure 9 As shown in Figure 2, the potential distribution on the lead sheath and armor is similar to that of the single-core submarine cable, but its value is smaller than that of the single-core submarine cable.

[0112] The leakage current density distribution of the three-core submarine cable can be shown as follows: Figure 10 As shown in FIG, the leakage current density distribution is similar to that of the single-core submarine cable, but its value is smaller than that of the single-core submarine cable. This is because the outer diameter of the single-core submarine cable is smaller than that of the three-core submarine cable.

[0113] In this example, different submarine cable lengths, electrode distances, and end distances can be set in the CDEGS grounding software to obtain different electromagnetic field distribution change results.

[0114] For example, the length of the three-core submarine cable can be changed to 3000m, 3500m, 4000m, 4500m, and 5000m respectively. Then, the current distribution, potential distribution, and leakage current density distribution on the armor layer of the submarine cable can be calculated by the calculation model in the CDEGS grounding software to obtain the results of the electromagnetic field distribution change. Among them, the current distribution on the armor layer under different submarine cable lengths can be as follows: Figure 11A As shown in the figure, the potential distribution on the armor layer at different submarine cable lengths can be shown as follows: Figure 11B As shown in the figure, the leakage current density distribution on the armor layer at different submarine cable lengths can be shown as follows: Figure 11C shown.

[0115] As an example, the effect of the length of the submarine cable on the current distribution can be shown as the current at one end far away from the ocean DC grounding electrode is positively correlated with the length of the submarine cable, that is, the current at one end far away from the ocean DC grounding electrode increases with the increase of the length of the submarine cable; as another example, the effect of the length of the submarine cable on the potential distribution can be shown as the potential at one end far away from the ocean DC grounding electrode is negatively correlated with the length of the submarine cable, that is, the potential at one end far away from the ocean DC grounding electrode decreases with the increase of the length of the submarine cable; as another example, the effect of the length of the submarine cable on the distribution of the leakage current density can be shown as the increase of the leakage current density at both ends is negatively correlated with the length of the submarine cable, that is, the increase trend of the local increase at both ends of the submarine cable becomes slow as the length of the submarine cable increases. Specifically, as Figures 11A to 11C As shown in the figure, the increase in the length of the submarine cable will not have a significant impact on the current distribution, potential distribution and leakage current density distribution near the marine DC grounding electrode, but will have a greater impact on the end far away from the marine grounding electrode. Specifically, as the length of the submarine cable increases, the current value at a certain distance from the marine grounding electrode is larger and the potential is lower, but the current at the end of the submarine cable is similar, and the leakage current density shows a local steep increase at the end of the submarine cable. As the length of the submarine cable increases, the current rise at the end of the submarine cable is slowed down.

[0116] The distribution change of the electromagnetic field distribution affected by the electrode distance can be shown as follows: 12A to 12CAs shown. For example, the electrode distance between the three-core submarine cable and the marine DC grounding electrode can be changed to 50m, 100m, 150m, 200m, and 250m respectively. Then, the current distribution, potential distribution, and leakage current density distribution on the armor layer of the submarine cable can be calculated by the calculation model in the CDEGS grounding software to obtain the results of the electromagnetic field distribution change. Among them, the current distribution on the armor layer at different electrode distances can be as follows Figure 12A As shown, the potential distribution on the armor layer at different electrode distances can be shown as Figure 12B As shown, the leakage current density distribution on the armor layer at different electrode distances can be shown as Figure 12C shown.

[0117] like 12A to 12C As shown in the figure, the effect of electrode distance on electromagnetic field distribution can be shown as a negative correlation between the current, potential, and leakage current density of the armor layer and the electrode distance. That is, the closer the electrode distance, the greater the current, potential, and leakage current density of the armor layer. Specifically, the closer the submarine cable is to the electrode of the marine DC grounding electrode, the greater the current on the armor layer of the submarine cable, the higher the potential, and the greater the leakage current density. As the electrode distance gradually increases, the decreasing trend gradually weakens. Therefore, in electrical engineering, directly increasing the electrode distance between the submarine cable and the marine DC grounding electrode can significantly slow down the flow of DC current from the marine DC grounding electrode into the submarine cable armor layer, thereby reducing the impact of DC current on submarine cable corrosion.

[0118] The distribution change of the electromagnetic field distribution affected by the end distance can be shown as follows: 13A to 13C As shown. For example, the end distance between the marine DC grounding electrode and the left end of the three-core submarine cable can be changed to 200m, 300m, 4000m, 500m, and 600m respectively. Then, the current distribution, potential distribution, and leakage current density distribution on the armor layer of the submarine cable can be calculated by the calculation model in the CDEGS grounding software to obtain the result of the electromagnetic field distribution change. Among them, the current distribution on the armor layer at different end distances can be as follows Figure 13A As shown, the potential distribution on the armor layer at different end distances can be as follows Figure 13B As shown, the distribution of leakage current density on the armor layer at different end distances can be shown as Figure 13C shown.

[0119] like 13A to 13CAs shown in the figure, the effect of the end distance on the electromagnetic field distribution can be shown as the current, potential and leakage current density of the armor layer are negatively correlated with the end distance, that is, the closer the end distance is, the higher the current of the armor layer is. Specifically, the current distribution shows a peak value near the left and right sides of the marine DC grounding electrode. The smaller the end distance from one end, the smaller the current peak value on that side, while the current peak value on the other side is larger. The positions of the two peaks also shift to the left as the end distance from the grounding electrode to the left end decreases. The potential distribution shows that as the marine grounding electrode approaches the left end, the potential peak also shifts to that side, and the peak value increases. The change pattern of the current density also shows the same pattern. As the grounding electrode approaches the left cable end, the maximum value of the leakage current density on the armor layer gradually decreases.

[0120] In summary, the current and leakage current density on the armor layer of the submarine cable section near the marine DC grounding electrode are the largest, and the potential is also the highest, and the current distribution, potential distribution and leakage current density distribution show a trend of decreasing towards the two ends of the submarine cable; and as the distance of the submarine cable increases, the current, potential and leakage current density near the grounding electrode change little, and the main impact is on the electromagnetic field distribution at the other end. That is, the DC current, potential and leakage current density distribution on the armor layer can be reduced by increasing the distance between the marine DC grounding electrode and the submarine cable, and moving the marine DC grounding electrode to one side will cause the maximum current and potential points to shift to that side, and the maximum value gradually increases.

[0121] In this example, the annual corrosion depth of a three-phase single-core submarine cable and a three-core submarine cable under typical working conditions can be calculated based on the above data.

[0122] For example, when calculating the corrosion amount, a typical operating condition can be selected for calculation. For example, under the operating conditions of a rated injection current of 3125A, an annual single-core operating time of 5 hours, and an annual operating ampere-hour of 15625A·h, the corrosion of the armored steel wire layer of a single-core submarine cable and a three-core submarine cable at the location with the maximum leakage current density can be specifically referred to in Table 5 below:

[0123] Table 5 Calculation results of maximum corrosion of three-core submarine cables and single-core submarine cables

[0124]

[0125] As shown in Table 5, at an annual operating ampere-hour of 15,625 A·h, the maximum corrosion depths for 220kV single-core submarine cables and 220kV three-core submarine cables are 0.2mm and 0.11mm, respectively. This indicates that corrosion is more severe for single-core submarine cables. This is due, firstly, to the smaller outer diameter and smaller cross-sectional area of ​​the steel wire layer, resulting in a higher leakage current density and increased corrosion. Second, the mechanical strength required for single-core submarine cables is lower than that of three-core submarine cables, resulting in a thinner armored steel wire layer and a greater susceptibility to mechanical strength degradation due to corrosion.

[0126] If the annual operating ampere-hours increase tenfold, for example, in a long-term monopole operation project, when the annual monopole operation time reaches 50 hours, that is, the annual operating ampere-hours reach 156,250, the annual corrosion depth will reach 2mm and 11mm. The armored steel wire layer thickness of single-core submarine cables and three-core submarine cables is 4mm and 6mm, which means that the corrosion depth will reach 1 / 2 and 1 / 6 respectively. Therefore, for marine DC grounding electrodes that need to operate in monopole conditions for a long time during the initial construction period, attention should be paid to the local mechanical strength loss caused by DC current corrosion on the submarine cable. Over time, this area will become susceptible to external stress and damage, posing a safety hazard to the transmission system. In this case, the local mechanical strength can be reduced to ensure the safe operation of the submarine cable.

[0127] In an embodiment of the present application, in the preset simulation software, after the submarine cable is grounded, the current of the marine DC grounding electrode can flow into the sheath layer of the submarine cable, and flow into the armor layer of the submarine cable through the sheath layer, that is, the marine DC grounding electrode affects the armor layer of the submarine cable. At this time, a calculation model of the influence of the marine DC grounding electrode on the armor layer can be obtained. The calculation model is constructed based on the soil stratification model, the grounding electrode model and the cable model. At this time, the electromagnetic field distribution of the armor layer and the sheath layer under the influence of the marine DC grounding electrode can be calculated based on the above-mentioned model, and the influence of the cable length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution is analyzed to obtain the electromagnetic field distribution change result, and then the corrosion condition of the armor layer is determined according to the electromagnetic field distribution change. The electromagnetic field distribution on the armor and sheath of the submarine cable when the marine DC grounding electrode is in operation is calculated through a computational model. Based on an analysis of multiple factors affecting the electromagnetic field distribution of the submarine cable, the corrosion of the armor layer is evaluated based on the results of the electromagnetic field distribution changes. This can achieve a new strategy for analyzing and calculating the impact of the DC current on the nearby submarine cables when the marine DC grounding electrode is in single-pole operation. This helps to solve the problem of the DC current of the marine DC grounding electrode accelerating the corrosion of the armor layer when it flows into the armor layer, leading to breakage and damage of the armor layer under the influence of the external environment.

[0128] It should be noted that for the method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present application are not limited by the order of the actions described, because according to the embodiments of the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present application.

[0129] Reference Figure 14 , shows a structural block diagram of a submarine cable corrosion calculation device based on a marine DC grounding electrode provided by an embodiment of the present application. In the preset simulation software, grounding rods are provided at the grounding ends of the submarine cable. The grounding rods are connected to the armor layer and sheath layer of the submarine cable. Specifically, the device may include the following modules:

[0130] The calculation model acquisition module 1401 is used to obtain a calculation model of the impact of the marine DC grounding electrode on the armor layer; the calculation model is constructed based on the soil layer model, the grounding electrode model and the cable model;

[0131] The electromagnetic field distribution generating module 1402 is used to calculate the electromagnetic field distribution of the armor layer and the sheath layer according to the soil layer model, the ground electrode model and the cable model;

[0132] The distribution change result generating module 1403 is used to analyze the influence of the length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution, and obtain the electromagnetic field distribution change result;

[0133] The corrosion condition determination module 1404 is used to determine the corrosion condition of the armor layer according to the result of the change in the electromagnetic field distribution.

[0134] In some embodiments of the present application, the soil layer model is used to indicate the distribution of the current entering the sea, the ground electrode model is used to indicate the injection distance of the submarine cable, and the cable model is used to indicate the electrical characteristic parameters of the armor layer and the sheath layer; the electromagnetic field distribution generation module 1402 may include the following submodules:

[0135] The electromagnetic field distribution generation submodule is used to calculate the current distribution, potential distribution and leakage current density distribution of the armor layer and sheath layer based on the sea current distribution, injection distance and electrical characteristic parameters through the calculation model.

[0136] In some embodiments of the present application, the current distribution of the armor layer is such that the current at the grounding point close to the marine DC grounding electrode is greater than the current at other locations; the potential distribution of the armor layer is such that the potential decreases from the center position aligned with the marine DC grounding electrode toward both ends; and the leakage current density distribution of the armor layer is such that the leakage current density at the grounding point close to the marine DC grounding electrode is greater than the leakage current density on both sides of the grounding point, and the leakage current density at the center position aligned with the marine DC grounding electrode is less than the leakage current density at both ends.

[0137] The current distribution of the sheath layer shows that the current magnitude is equal at all positions; the potential distribution of the sheath layer shows that the potential decreases from the end close to the marine DC grounding electrode to the end farthest from the marine DC grounding electrode; the leakage current density distribution of the sheath layer shows that the leakage current density at all positions is 0.

[0138] In some embodiments of the present application, the results of the change in electromagnetic field distribution show that the current at one end away from the ocean DC grounding electrode is positively correlated with the length of the submarine cable, the potential at one end away from the ocean DC grounding electrode is negatively correlated with the length of the submarine cable, and the local increase in leakage current density at both ends is negatively correlated with the length of the submarine cable; the current, potential and leakage current density of the armor layer are negatively correlated with the electrode distance; the current, potential and leakage current density of the armor layer are negatively correlated with the end distance.

[0139] In some embodiments of the present application, the corrosion condition includes the corrosion severity of the armor layer and the service life of the armor layer; the corrosion condition determination module 1404 may include the following submodules:

[0140] The corrosion condition generation submodule is used to obtain power-on data based on the changes in the electromagnetic field distribution, and calculate the corrosion depth and corrosion rate under a specific leakage current density based on the power-on data; among them, the corrosion depth is used to indicate the severity of corrosion of the armor layer, and the corrosion rate is used to indicate the service life of the armor layer.

[0141] In some embodiments of the present application, the power-on data includes current intensity, power-on time, number of electron transfers, and metal atomic mass at a specific leakage current density; the corrosion condition generation submodule may include the following units:

[0142] The corrosion situation generating unit is used to calculate the corrosion amount under a specific leakage current density based on the current intensity, power-on time, electron transfer number and metal atomic mass under the specific leakage current density, and the Faraday constant by adopting Faraday's law; obtain the corrosion depth and corrosion area under the specific leakage current density based on the corrosion amount under the specific leakage current density; and calculate the corrosion rate under the specific leakage current density based on the corrosion area, the current intensity, electron transfer number and metal atomic mass under the specific leakage current density, and the Faraday constant.

[0143] In some embodiments of the present application, the submarine cable includes a three-phase single-core submarine cable and a three-core submarine cable.

[0144] In an embodiment of the present application, in the preset simulation software, after the submarine cable is grounded, the current of the marine DC grounding electrode can flow into the sheath layer of the submarine cable, and flow into the armor layer of the submarine cable through the sheath layer, that is, the marine DC grounding electrode affects the armor layer of the submarine cable. At this time, a calculation model of the influence of the marine DC grounding electrode on the armor layer can be obtained. The calculation model is constructed based on the soil stratification model, the grounding electrode model and the cable model. At this time, the electromagnetic field distribution of the armor layer and the sheath layer under the influence of the marine DC grounding electrode can be calculated based on the above-mentioned model, and the influence of the cable length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution is analyzed to obtain the electromagnetic field distribution change result, and then the corrosion condition of the armor layer is determined according to the electromagnetic field distribution change. The electromagnetic field distribution on the armor and sheath of the submarine cable when the marine DC grounding electrode is in operation is calculated through a computational model. Based on an analysis of multiple factors affecting the electromagnetic field distribution of the submarine cable, the corrosion of the armor layer is evaluated based on the results of the electromagnetic field distribution changes. This can achieve a new strategy for analyzing and calculating the impact of the DC current on the nearby submarine cables when the marine DC grounding electrode is in single-pole operation. This helps to solve the problem of the DC current of the marine DC grounding electrode accelerating the corrosion of the armor layer when it flows into the armor layer, leading to breakage and damage of the armor layer under the influence of the external environment.

[0145] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0146] The present application also provides an electronic device, Figure 15 The provided electronic device 1500 includes a memory 1510, a processor 1520, and a computer program 1511 stored in the memory 1510 and capable of running on the processor 1520. When the computer program 1511 is executed by the processor, the various processes of the above-mentioned embodiment of the submarine cable corrosion calculation method based on the marine DC grounding electrode are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0147] The present application also provides a computer-readable storage medium. Figure 16 The computer-readable storage medium 1600 provided stores a computer program 1511. When the computer program 1511 is executed by the processor, each process of the above-mentioned embodiment of the submarine cable corrosion calculation method based on the marine DC grounding electrode is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0148] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0149] It should be noted that the terms "first", "second", etc. in the description and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate so that the embodiments described herein can be implemented in an order other than that shown or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products or devices. The division of modules that appears in the embodiments of the present application is only a logical division. In actual applications, there may be other division methods. For example, multiple modules can be combined into or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between each other shown or discussed can be through some interfaces, and the indirect coupling or communication connection between modules can be electrical or other similar forms, which are not limited in the embodiments of the present application. Moreover, the modules or sub-modules described as separate components may or may not be physically separated, may or may not be physical modules, or may be distributed into multiple circuit modules, and some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiment of the present application.

[0150] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0151] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and modules described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0152] In the several embodiments provided in the embodiments of the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms.

[0153] 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 modules. Some or all of the modules may be selected to achieve the purpose of the present embodiment according to actual needs.

[0154] In addition, the functional modules in each embodiment of the present application can be integrated into a processing module, or each module can exist physically separately, or two or more modules can be integrated into a module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0155] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0156] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in accordance with the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium that can be stored on a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, hard disk, or magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0157] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0158] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded into a computer or other programmable data processing terminal device, so that a series of operation steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for implementing the process in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0159] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0160] Finally, it should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0161] The above is a detailed introduction to the technical solutions provided in the embodiments of the present application. Specific examples are used in the embodiments of the present application to illustrate the principles and implementation methods of the embodiments of the present application. The description of the above embodiments is only used to help understand the methods and core ideas of the embodiments of the present application. At the same time, for those skilled in the art, according to the ideas of the embodiments of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the embodiments of the present application.

Claims

1. A method for calculating submarine cable corrosion based on marine DC grounding electrodes, characterized in that: In the preset simulation software, the grounding ends at both ends of the submarine cable are provided with grounding rods, and the grounding rods are connected to the armor layer and the sheath layer of the submarine cable. The method includes: Obtaining a calculation model of the effect of the marine DC grounding electrode on the armor layer; the calculation model is constructed based on a soil layer model, a grounding electrode model, and a cable model; Calculating the electromagnetic field distribution of the armor layer and the sheath layer according to the soil layer model, the ground electrode model and the cable model; Analyzing the effects of the length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution, and obtaining a result of the change in the electromagnetic field distribution; The corrosion condition of the armor layer is determined according to the change result of the electromagnetic field distribution.

2. The method according to claim 1, characterized in that The soil layer model is used to indicate the distribution of the current entering the sea, the ground electrode model is used to indicate the injection distance of the submarine cable, and the cable model is used to indicate the electrical characteristic parameters of the armor layer and the sheath layer; the electromagnetic field distribution includes the current distribution, the potential distribution and the leakage current density distribution; The calculating of the electromagnetic field distribution of the armor layer and the sheath layer according to the soil layer model, the ground electrode model and the cable model includes: The calculation model is used to calculate the current distribution, potential distribution and leakage current density distribution of the armor layer and the sheath layer based on the sea-entry current distribution, the injection distance and the electrical characteristic parameters.

3. The method according to claim 2, characterized in that The current distribution of the armor layer shows that the current at the grounding point close to the marine DC grounding electrode is greater than the current at other positions; the potential distribution of the armor layer shows that the potential decreases from the center position of the marine DC grounding electrode to both ends; the leakage current density distribution of the armor layer shows that the leakage current density at the grounding point close to the marine DC grounding electrode is greater than the leakage current density on both sides of the grounding point, and the leakage current density at the center position of the marine DC grounding electrode is less than the leakage current density at both ends; The current distribution of the sheath layer shows that the current at each position is equal; the potential distribution of the sheath layer shows that the potential decreases from the end close to the marine DC grounding electrode to the end far away from the marine DC grounding electrode; the leakage current density distribution of the sheath layer shows that the leakage current density at each position is 0.

4. The method according to claim 1, wherein The results of the change in the electromagnetic field distribution show that the current at one end away from the marine DC grounding electrode is positively correlated with the length of the submarine cable, the potential at one end away from the marine DC grounding electrode is negatively correlated with the length of the submarine cable, and the local increase in the leakage current density at both ends is negatively correlated with the length of the submarine cable; the current, potential and leakage current density of the armor layer are negatively correlated with the distance from the electrode; the current, potential and leakage current density of the armor layer are negatively correlated with the distance from the end.

5. The method according to claim 1, wherein The corrosion condition includes the severity of corrosion of the armor layer and the service life of the armor layer; and determining the corrosion condition of the armor layer according to the change result of the electromagnetic field distribution includes: Obtaining power-on data according to the result of the change in the electromagnetic field distribution, and calculating the corrosion depth and corrosion rate under a specific leakage current density according to the power-on data; The corrosion depth is used to indicate the severity of the corrosion of the armor layer, and the corrosion rate is used to indicate the service life of the armor layer.

6. The method according to claim 5, characterized in that The power-on data includes current intensity, power-on time, number of electron transfers, and metal atomic mass at the specific leakage current density; and calculating the corrosion depth and corrosion rate at the specific leakage current density based on the power-on data includes: The corrosion amount under the specific leakage current density is calculated using Faraday's law based on the current intensity, power-on time, number of electron transfers, metal atomic mass, and Faraday's constant under the specific leakage current density. Based on the corrosion amount under the specific leakage current density, obtaining the corrosion depth and corrosion area under the specific leakage current density; The corrosion rate at the specific leakage current density is calculated based on the corrosion area, the current intensity at the specific leakage current density, the number of electron transfers, the atomic mass of the metal, and the Faraday constant.

7. The method according to any one of claims 1 to 6, characterized in that The submarine cables include three-phase single-core submarine cables and three-core submarine cables.

8. A submarine cable corrosion calculation device based on a marine DC grounding electrode, characterized in that: In the preset simulation software, the grounding ends at both ends of the submarine cable are provided with grounding rods, and the grounding rods are connected to the armor layer and the sheath layer of the submarine cable. The device includes: A calculation model acquisition module is used to obtain a calculation model of the impact of the marine DC grounding electrode on the armor layer; the calculation model is constructed based on a soil layer model, a grounding electrode model, and a cable model; an electromagnetic field distribution generating module, configured to calculate the electromagnetic field distribution of the armor layer and the sheath layer according to the soil layer model, the ground electrode model, and the cable model; a distribution change result generating module, configured to analyze the effects of the length of the submarine cable, the electrode distance between the submarine cable and the marine DC grounding electrode, and the end distance between the marine DC grounding electrode and the end of the submarine cable on the electromagnetic field distribution, and obtain an electromagnetic field distribution change result; The corrosion condition determination module is used to determine the corrosion condition of the armor layer according to the change result of the electromagnetic field distribution.

9. An electronic device, characterized in that: include: A processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein when the computer program is executed by the processor, the method for calculating submarine cable corrosion based on a marine DC grounding electrode as described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for calculating submarine cable corrosion based on a marine DC grounding electrode as claimed in any one of claims 1 to 7 is implemented.

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