A method for determining parameters of a three-core submarine cable grounding structure

Abstract

The present invention discloses a method for determining the parameters of a three-core submarine cable grounding structure, wherein the grounding structure is as follows: resistors are connected in series at both ends of a three-phase sheath and then interconnected and grounded, and both ends of the armor of the three-core submarine cable are directly grounded. The method comprises: obtaining the basic parameters of the three-core submarine cable, including geometric dimensions and material characteristic parameters; calculating the impedance and admittance parameters of the three-core submarine cable in the equivalent circuit of the grounding structure; solving the differential equation of the submarine cable transmission process, and obtaining a calculation model of the submarine cable sheath and armor induced voltage and induced current with the resistance value of the sheath series resistance as a variable; based on the calculation model, with the sheath series resistance as a variable and the minimum sheath induced current as the optimization target, solving the pre-constructed sheath series resistance optimization model, and obtaining the sheath series resistance. The present invention can select a reasonable grounding structure and parameters for three-core submarine cables with different structures and loads, effectively reduce the sheath induced current and make the induced voltage meet the engineering requirements, and ensure the safety of the submarine cable operation.

Description

Technical Field

[0001] The invention relates to the technical field of submarine cable AC transmission, in particular to a method for determining grounding structure parameters of a three-core submarine cable. Background Art

[0002] With the construction of coastal cities and the development of offshore wind farms, marine power transmission and transformation projects have been developing rapidly in recent years. As one of the cores of marine power transmission and transformation projects, submarine cables are the main reason for the difficulty and high cost of marine power transmission and transformation projects. Current carrying capacity is one of the important parameters of submarine cables. Like land cables, it is the maximum current allowed to pass through the core conductor of the cable at the highest allowable temperature, which is closely related to the induced current on the metal sheath. Unlike land cables, submarine cables need to be equipped with armor layers to ensure the mechanical strength of the submarine cables; and due to the limitations of the laying environment, submarine cable lines cannot adopt measures such as sheath cross-interconnection and cable body transposition. In engineering, the metal sheaths and armor at both ends of the submarine cable are usually connected to the ground in parallel. At this time, the submarine cable will generate induced current on the sheath and armor, accompanied by large losses, causing the submarine cable sheath and armor to heat up, thereby limiting the current carrying capacity of the submarine cable; when the line is very long, a higher induced voltage will be formed on the sheath and armor far away from the grounding point, posing a threat to the submarine cable itself and the surrounding environment.

[0003] Since the induced voltage and current on the armor are much smaller than the induced voltage and current on the sheath, connecting a series resistor on the metal sheath at both ends of the submarine cable is a simple grounding solution to reduce losses and increase current carrying capacity, but the sheath induced voltage will increase with the increase of the series resistor. GB 50217 "Design Code for Power Engineering Cables" stipulates: When safety measures that can effectively prevent personnel from arbitrarily contacting the metal layer are not taken, the maximum value of the normal induced potential at any point on the metal layer of an AC single-core power cable that is not directly grounded shall not be greater than 50V; except for the above situation, it shall not be greater than 300V. For submarine cables, the current research on the impact of grounding methods on the induced voltage and current of sheaths and armor is mainly focused on single-core submarine cables. Nowadays, more and more three-core submarine cables are put into engineering applications, but there are currently no standards or regulations that give clear requirements for the grounding structure of three-core submarine cables. Summary of the invention

[0004] The purpose of the present invention is to provide a method for determining the grounding structure parameters of a three-core submarine cable, which can select a reasonable grounding structure and parameters for three-core submarine cables with different structures and loads, effectively reduce the sheath induced current, ensure that the induced voltage meets the engineering requirements, and ensure the safety of submarine cable operation. The technical solution adopted by the present invention is as follows.

[0005] In one aspect, the present invention provides a method for determining parameters of a three-core submarine cable grounding structure, comprising:

[0006] Obtaining basic parameters of the three-core submarine cable, wherein the basic parameters include geometric dimensions, structural form and material characteristic parameters;

[0007] Based on the basic parameters of the three-core submarine cable, the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit are calculated; wherein the grounding structure is: the two ends of the three-phase sheath are connected in series with resistors and then interconnected and grounded, and the two ends of the armor of the three-core submarine cable are directly grounded;

[0008] Based on the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit, by solving the differential equation of the submarine cable transmission process, a calculation model of the induced voltage and induced current of the submarine cable sheath and armor is obtained with the resistance value of the sheath series resistance as a variable.

[0009] Based on the calculation model, with the sheath series resistance as a variable and the minimum sheath induced current as an optimization target, a pre-constructed sheath series resistance optimization model is solved to obtain the sheath series resistance that minimizes the sheath induced current.

[0010] Optionally, the optimization target of the sheath series resistance optimization model is to minimize the induced current at the sheath head end; the objective function of the pre-constructed sheath series resistance optimization model is:

[0011] f min =|i sa (0)|+|i sb (0)|+|i sc (0)|

[0012] In the formula, i sa (0),i sb (0),i sc (0) represents the induced current at the beginning of the three-phase sheath of A, B, and C respectively; the constraint condition for the optimization solution of the objective function is that the sheath induced voltage of the three-core submarine cable satisfies: 0≤u sa (0),u sb (0),u sc (0)≤150(V), where u sa (0),u sb (0),u sc (0) represents the induced voltage at the beginning of the three-phase sheath, A, B, and C respectively.

[0013] Optionally, based on the basic parameters of the three-core submarine cable, the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit are calculated to obtain an impedance matrix Z in the following form: f and the admittance matrix Y f :

[0014]

[0015]

[0016] Where, subscripts a, b, c represent the core conductors of phase A, phase B, and phase C of the submarine cable, respectively; subscripts sa, sb, and sc represent the sheath conductors of phase A, phase B, and phase C of the submarine cable, respectively; and subscript p represents the armored conductor of the submarine cable; the impedance matrix Z f In the mth row and mth column, the element z mm (1≤m≤7) represents the self-impedance of a conductor m per unit length, and the element z in the mth row and nth column is mn (1≤m,n≤7,m≠n) represents the mutual impedance between conductor m and conductor n per unit length; the admittance matrix Y f In the mth row and mth column, the element y mm (1≤m≤7) represents the self-admittance of the conductor m per unit length, and the element y in the mth row and nth column is mn (1≤m,n≤7,m≠n) represents the mutual admittance between conductors m and n per unit length.

[0017] The present invention adopts pscad software, based on the basic parameters of the three-core submarine cable, to calculate the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit. The specific calculation formula can adopt the existing technology. In actual calculation, only the basic parameters of the three-core submarine cable need to be input to obtain the values ​​of each element in the impedance matrix and the admittance matrix.

[0018] Optionally, the differential equation of the submarine cable transmission process is expressed as:

[0019]

[0020] Where U f =[u a (x) u sa (x) u b (x) u sb (x) u c (x) u sc (x) u p (x)] T is the column vector of the voltage of the seven conductors of the submarine cable core, sheath and armor to the ground, I f =[i a (x) i sa (x) i b (x) i sb (x) i c (x) i sc (x) i p (x)] T is the column vector of the current in the seven conductors of the submarine cable core, sheath and armor; u a (x),u b (x),u c (x) and ia (x),i b (x),i c (x) are the three-phase core line voltage and current at a distance x from the head end, u sa (x),u sb (x),u sc (x) and i sa (x),i sb (x),i sc (x) are the three-phase sheath induced voltage and current at a distance x from the head end, u p (x) and i p (x) are the induced voltage and current of the armor at a distance x from the head end.

[0021] When solving the differential equation of the above cable transmission process, the present invention solves it based on the phase mode transformation principle, and the boundary condition is expressed as:

[0022]

[0023] Where U n is the line rated voltage of the submarine cable, the superscript i is the imaginary unit of the complex number, l is the length of the submarine cable, R L The single-phase load connected to the end of the submarine cable; R e is the equivalent earth leakage resistance of the armor directly grounded, R c The resistor is connected in series with the sheath.

[0024] For each element in the following matrix, x is 0 or l, which corresponds to the beginning and end of the submarine cable respectively:

[0025] U f =[u a (x) u sa (x) u b (x) u sb (x) u c (x) u sc (x) u p (x)] T

[0026] I f =[i a (x) i sa (x) i b (x) i sb (x) i c (x) i sc (x) i p (x)] T

[0027] In a second aspect, the present invention provides a device for determining parameters of a three-core submarine cable grounding structure, which is characterized by comprising:

[0028] A submarine cable parameter acquisition module, configured to acquire basic parameters of the three-core submarine cable, the basic parameters including geometric dimensions, structural form and material characteristic parameters;

[0029] The impedance and admittance calculation module is configured to calculate the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit based on the basic parameters of the three-core submarine cable; wherein the grounding structure is: two ends of the three-phase sheath are connected in series with resistors and then interconnected and grounded, and two ends of the armor of the three-core submarine cable are directly grounded;

[0030] The calculation model determination module is configured to obtain a calculation model of the induced voltage and induced current of the submarine cable sheath and armor with the resistance value of the sheath series resistance as a variable by solving the differential equation of the submarine cable transmission process based on the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit;

[0031] And, the sheath series resistance determination module is configured to solve the pre-constructed sheath series resistance optimization model based on the calculation model, with the sheath series resistance as a variable and the minimum sheath induced current as the optimization target, to obtain the sheath series resistance that minimizes the sheath induced current.

[0032] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for determining the grounding structure parameters of a three-core submarine cable as described in the first aspect.

[0033] Beneficial Effects

[0034] The method for determining the grounding structure parameters of a three-core submarine cable of the present invention can select the optimal sheath series resistance for three-core submarine cables of different models and loads, which can not only effectively reduce the loss of the submarine cable and increase the current carrying capacity of the submarine cable, but also meet the engineering requirements of the induced voltage on the submarine cable sheath, ensure the safe operation of the submarine cable, and provide a reference for the grounding scheme of the submarine cable in the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Shown is a schematic diagram of the grounding structure of a three-core AC submarine cable

[0036] Figure 2 The following is the equivalent circuit of the distributed parameters of the three-core AC submarine cable.

[0037] Figure 3 Shown is a flow chart of the implementation of the method for determining the grounding structure parameters of a three-core submarine cable of the present invention. DETAILED DESCRIPTION

[0038] The invention is further described below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] This embodiment introduces a method for determining the grounding structure parameters of a three-core submarine cable. Figure 3 , methods include:

[0041] Obtaining basic parameters of the three-core submarine cable, wherein the basic parameters include geometric dimensions, structural form and material characteristic parameters;

[0042] Based on the basic parameters of the three-core submarine cable, the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit are calculated; wherein the grounding structure is: the two ends of the three-phase sheath are connected in series with resistors and then interconnected and grounded, and the two ends of the armor of the three-core submarine cable are directly grounded;

[0043] Based on the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit, by solving the differential equation of the submarine cable transmission process, a calculation model of the induced voltage and induced current of the submarine cable sheath and armor is obtained with the resistance value of the sheath series resistance as a variable.

[0044] Based on the calculation model, with the sheath series resistance as a variable and the minimum sheath induced current as an optimization target, a pre-constructed sheath series resistance optimization model is solved to obtain the sheath series resistance that minimizes the sheath induced current.

[0045] The following describes the contents involved in the method of this embodiment using a specific application scenario.

[0046] 1. Establishing the grounding structure system model of three-core AC submarine cable

[0047] refer to Figure 1 As shown in the figure, the total length of the three-core AC submarine cable line is 13000m. The grounding structure is that the two ends of the sheath are connected in series with resistors and the two ends of the armor are directly grounded. The power end is the first end and the load end is the last end. a (0),i b (0),i c (0) and i a (l),i b (l),i c (l) are the three-phase core currents at the beginning and end of the submarine cable, i sa (0),i sb (0),i sc (0) and i sa (l),i sb (l),i sc (l) are the three-phase sheath currents at the beginning and end, i p (0) and i p (l) are the armor currents at the beginning and end respectively; R L is the single-phase load connected to each phase core of the submarine cable, RL =250+j25π(Ω); R e is the earth equivalent leakage resistance, R e =0.05Ω, R c The resistor is connected in series with the sheath.

[0048] 2. Circuit Equivalence and Admittance and Impedance Calculation

[0049] The basic parameters of the three-core submarine cable whose sheath grounding resistance is to be determined are obtained, including the geometric dimensions, material properties, structural form (such as arrangement method) and other data of the submarine cable, and the various admittance impedance data in the three-core submarine cable grounding system are calculated using the basic parameter data obtained.

[0050] refer to Figure 2 The distributed parameter equivalent circuit of the three-core AC submarine cable shown in FIG. 1 shows only the mutual impedance and mutual admittance of the A-phase core in addition to the self-impedance and self-admittance of each phase core. Therefore, in this embodiment, the admittance and impedance data to be calculated are as follows: f and the admittance matrix Y f :

[0051]

[0052]

[0053] Where, subscripts a, b, c represent the core conductors of phase A, phase B, and phase C of the submarine cable, respectively; subscripts sa, sb, and sc represent the sheath conductors of phase A, phase B, and phase C of the submarine cable, respectively; and subscript p represents the armored conductor of the submarine cable; the impedance matrix Z f In the mth row and mth column, the element z mm (1≤m≤7) represents the self-impedance of a conductor m per unit length, and the element z in the mth row and nth column is mn (1≤m,n≤7,m≠n) represents the mutual impedance between conductor m and conductor n per unit length; the admittance matrix Y f In the mth row and mth column, the element y mm (1≤m≤7) represents the self-admittance of the conductor m per unit length, and the element y in the mth row and nth column is mn (1≤m,n≤7,m≠n) represents the mutual admittance between conductors m and n per unit length.

[0054] The above impedance matrix Z f and the admittance matrix Y fThe values ​​of each element in can be calculated by using the existing technology according to the basic parameters of the submarine cable. In this embodiment, pscad software is preferably used for calculation. By pre-configuring the algorithm model and inputting parameters such as geometric dimensions and material properties in the software, the specific values ​​in the matrix can be obtained. Since the actual calculation result is a seventh-order complex matrix, it is inconvenient to give the specific values, so the impedance matrix Z f and the admittance matrix Y f The elements in are still represented by symbols.

[0055] 3. Determine the calculation model of the induced voltage and induced current of the submarine cable sheath and armor with the sheath grounding resistance as the variable

[0056] Reference again Figure 2 As shown in the figure, u a (x),u b (x),u c (x) and i a (x),i b (x),i c (x) are the three-phase core line voltage and current at a distance xm from the head end, u sa (x),u sb (x),u sc (x) and i sa (x),i sb (x),i sc (x) are the induced voltage and current of the three-phase sheath at a distance xm from the head end, u p (x) and i p (x) are the induced voltage and current of the armor at a distance xm from the head end.

[0057] according to Figure 2 The differential equations of the submarine cable transmission process are listed as follows:

[0058]

[0059] Where U f =[u a (x) u sa (x) u b (x) u sb (x) u c (x) u sc (x) u p (x)] T is the column vector of the voltage of the seven conductors of the submarine cable core, sheath and armor to the ground, I f =[i a (x) i sa (x) i b (x) i sb (x) ic (x) i sc (x) i p (x)] T is the column vector of the current in the seven conductors of the submarine cable core, sheath and armor;

[0060] Based on the phase transformation principle, the differential equation of the above cable transmission process is solved, where the boundary conditions are expressed as:

[0061]

[0062] Where U n is the line rated voltage of the submarine cable, the superscript i is the imaginary unit of the complex number, l is the length of the submarine cable, R L The single-phase load connected to the end of the submarine cable; R e is the equivalent earth leakage resistance of the armor directly grounded, R c The resistor is connected in series with the sheath.

[0063] The calculation model of the submarine cable sheath and armor induced voltage and induced current with the sheath grounding resistance as a variable can output the corresponding sheath and armor induced voltage and induced current when different sheath series resistances are input.

[0064] 4. Constructing the ground resistance optimization model

[0065] In this embodiment, the optimization variable of the optimization model is the resistance value of the sheath series resistor, that is, R c ; The optimization objective of the optimization model is to minimize the induced current at the first end of the sheath, and the objective function is:

[0066] f min =|i sa (0)|+|i sb (0)|+|i sc (0)|

[0067] In the formula, i sa (0),i sb (0),i sc (0) represents the induced current of the first section of the three-phase sheath A, B, and C respectively

[0068] f is closely related to the structure, arrangement, line length and load of the submarine cable. At present, the engineering generally requires that the induced voltage of the sheath of a three-core submarine cable is not greater than 150V, so the constraint condition for solving the problem in this embodiment is set to 0≤u sa (0),u sb (0),u sc (0)≤150(V).

[0069] 5. Determine the sheath grounding resistance

[0070] After the objective function and solution constraints are determined, based on the calculation model of the induced voltage and induced current of the submarine cable sheath and armor with the sheath grounding resistance as the variable, the optimal grounding resistance value can be selected from different sheath series resistance schemes. At the same time, the sheath induced voltage and current under the grounding structure can also be output for comparative analysis with the original current and voltage results, providing a certain reference for the engineering implementation of the submarine cable grounding scheme.

[0071] Through calculation, when the sheath series resistance in this embodiment is 0.789Ω, the objective function value is f min =0.1765+0.1891+0.1878=0.5534(kA), at this time the three-phase sheath induced voltage is u sa (0) = 138.5 V, u sb (0) = 149.9 V, u sc (0) = 148.2 V. Compared with the grounding structure without a series resistor in the sheath, f = 0.2434 + 0.2555 + 0.2543 = 0.7533 (kA) when no series resistor is connected. It can be seen that the grounding structure under the sheath series resistor scheme effectively reduces the induced current of the sheath and makes the induced voltage of the sheath meet the engineering requirements, thereby reducing the sheath loss of the submarine cable, increasing the current carrying capacity of the submarine cable, and ensuring the safe operation of the submarine cable.

[0072] Example 2

[0073] Based on the same inventive concept as that of Embodiment 1, this embodiment introduces a device for determining parameters of a three-core submarine cable grounding structure, comprising:

[0074] A submarine cable parameter acquisition module, configured to acquire basic parameters of the three-core submarine cable, the basic parameters including geometric dimensions, structural form and material characteristic parameters;

[0075] The impedance and admittance calculation module is configured to calculate the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit based on the basic parameters of the three-core submarine cable; wherein the grounding structure is: two ends of the three-phase sheath are connected in series with resistors and then interconnected and grounded, and two ends of the armor of the three-core submarine cable are directly grounded;

[0076] The calculation model determination module is configured to obtain a calculation model of the induced voltage and induced current of the submarine cable sheath and armor with the resistance value of the sheath series resistance as a variable by solving the differential equation of the submarine cable transmission process based on the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit;

[0077] And, the sheath series resistance determination module is configured to solve the pre-constructed sheath series resistance optimization model based on the calculation model, with the sheath series resistance as a variable and the minimum sheath induced current as the optimization target, to obtain the sheath series resistance that minimizes the sheath induced current.

[0078] The specific functional implementation of the above functional modules refers to the relevant content of the method in Example 1 and will not be repeated here.

[0079] Example 3

[0080] This embodiment introduces a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the method for determining the grounding structure parameters of a three-core submarine cable as described in Embodiment 1 is implemented.

[0081] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0082] The present application is described with reference to the flowcharts and / or block diagrams of the methods, 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 device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. 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.

[0083] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0084] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0085] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A method for determining parameters of a three-core submarine cable grounding structure, characterized in that: include: Obtaining basic parameters of the three-core submarine cable, wherein the basic parameters include geometric dimensions, structural form and material characteristic parameters; Based on the basic parameters of the three-core submarine cable, the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit are calculated; wherein the grounding structure is: the two ends of the three-phase sheath are connected in series with resistors and then interconnected and grounded, and the two ends of the armor of the three-core submarine cable are directly grounded; Based on the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit, by solving the differential equation of the submarine cable transmission process, a calculation model of the induced voltage and induced current of the submarine cable sheath and armor is obtained with the resistance value of the sheath series resistance as a variable. Based on the calculation model, with the sheath series resistance as a variable and the minimum sheath induced current as an optimization target, a pre-constructed sheath series resistance optimization model is solved to obtain the sheath series resistance that minimizes the sheath induced current; The differential equation of the submarine cable transmission process is expressed as: ， In the formula, is the column vector of the voltage of the seven conductors of the submarine cable core, sheath and armor to the ground, is the column vector of the current in the seven conductors of the submarine cable core, sheath and armor; and They are the three-phase core line voltage and current at a distance x from the head end, and are the three-phase sheath induced voltage and current at a distance x from the head end, and The induced voltage and current of the armor at a distance x from the head end respectively; The differential equation for solving the submarine cable transmission process is solved based on the phase mode transformation principle, and the boundary conditions are expressed as: ， In the formula, is the line rated voltage of the submarine cable, the superscript i is the imaginary unit of the complex number, is the length of the submarine cable, Single-phase load connected to the end of the submarine cable; is the equivalent leakage resistance of the earth when the armor is directly grounded, The resistor is connected in series with the sheath.

2. The method according to claim 1, characterized in that: The optimization goal of the sheath series resistance optimization model is to minimize the induced current at the sheath head end; the objective function of the pre-constructed sheath series resistance optimization model is: ， In the formula, , , Respectively represent the induced current at the first end of the three-phase sheath A, B, and C; The constraint condition for optimizing the objective function is that the sheath induced voltage of the three-core submarine cable satisfies: ,in, Respectively represent the induced voltage at the beginning of the A, B, and C three-phase sheath.

3. The method according to claim 1, characterized in that: Based on the basic parameters of the three-core submarine cable, the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit are calculated to obtain the impedance matrix of the following form: and the admittance matrix : ， ， In the formula, subscripts a, b, c represent the core conductors of phase A, phase B, and phase C of the submarine cable respectively, subscripts sa, sb, and sc represent the sheath conductors of phase A, phase B, and phase C of the submarine cable respectively, and subscript p represents the armored conductor of the submarine cable; impedance matrix In Line Elements of a column Represents the conductor per unit length The self-impedance, Line Elements of a column Represents the conductor per unit length With conductor The mutual impedance between ; Admittance matrix In Line Elements of a column Represents the conductor per unit length The self-admittance, Line Elements of a column Represents the conductor per unit length and conductor The mutual admittance between .

4. The method according to claim 1 or 3, characterized in that: Based on the basic parameters of the three-core submarine cable, the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit are calculated using pscad software.

5. A device for determining the grounding structure parameters of a three-core submarine cable using the method for determining the grounding structure parameters of a three-core submarine cable according to any one of claims 1 to 4, characterized in that: include: A submarine cable parameter acquisition module, configured to acquire basic parameters of the three-core submarine cable, the basic parameters including geometric dimensions, structural form and material characteristic parameters; The impedance and admittance calculation module is configured to calculate the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit based on the basic parameters of the three-core submarine cable; wherein the grounding structure is: two ends of the three-phase sheath are connected in series with resistors and then interconnected and grounded, and two ends of the armor of the three-core submarine cable are directly grounded; The calculation model determination module is configured to obtain a calculation model of the induced voltage and induced current of the submarine cable sheath and armor with the resistance value of the sheath series resistance as a variable by solving the differential equation of the submarine cable transmission process based on the impedance and admittance parameters of the three-core submarine cable in the grounding structure equivalent circuit; And, the sheath series resistance determination module is configured to solve the pre-constructed sheath series resistance optimization model based on the calculation model, with the sheath series resistance as a variable and the minimum sheath induced current as the optimization target, to obtain the sheath series resistance that minimizes the sheath induced current.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for determining the grounding structure parameters of a three-core submarine cable as claimed in any one of claims 1 to 4 is implemented.

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