Method for establishing adaptive multi-section distributed parameter circuit model for submarine cable performance analysis

Abstract

The present invention discloses a method for establishing an adaptive multi-section distributed parameter circuit model for submarine cable performance analysis, comprising the following steps: S1, roughly dividing the cable into N mother sections according to geometric distribution, then dividing each mother section into a number of sub-sections, and then connecting them in series to form an equivalent circuit model for submarine cable overvoltage calculation; S2, using the finite element method to calculate the distributed parameters of each section of the circuit, determining the optimal segmentation scheme through an adaptive genetic algorithm, and finally establishing the optimal submarine cable overvoltage calculation equivalent circuit model. The submarine cable overvoltage calculation equivalent circuit model established by the present invention is more in line with engineering practice, can accurately reflect the actual situation of submarine cable overvoltage, and has a small amount of calculation and is simple to solve.

Description

Technical Field

[0001] The present invention relates to the field of cable technology, and in particular to a method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis. Background Art

[0002] Submarine cables refer to cables laid in the ocean. They have now developed into an important channel connecting the power grids on both sides of the strait or supplying power from the mainland to the islands. Submarine cable projects are often expensive and complex to repair. Once a fault occurs, the system will be decoupled, with serious consequences. Therefore, the safety and reliability requirements of submarine cable systems are relatively high. At present, domestic submarine cables mainly use metal shielding layers (outer layers) as channels for short-circuit currents. This structure is difficult to effectively protect the metal shielding layer when there is a super-strong lightning current and overvoltage, which will cause great harm to the cable core. For this reason, a semi-conductive layer is sometimes used between the inner and outer cables. This increases the difficulty and complexity of the analysis and calculation of this problem. In order to study the impact of the inner and outer semi-conductive layers on the transmission of high-frequency transient voltages such as lightning, so as to comprehensively evaluate the overvoltage level of submarine cables and provide a submarine cable insulation design scheme with high reliability, an accurate submarine cable equivalent circuit model needs to be established.

[0003] The overvoltage circuit model of submarine cables is divided into lumped parameter model and distributed parameter model. In the lumped circuit model, the current and voltage along the line are equal everywhere, while in the distributed parameter model, the current and voltage vary with the position. For high-frequency overvoltage, since its wavelength (equivalent wavelength) is actually only a few meters or even shorter, which is much smaller than the physical size of the power system line, the lumped parameter model can no longer analyze the distribution law of the actual overvoltage in the submarine cable, and calculation and analysis must be based on the distributed parameter model.

[0004] For simple distributed parameter circuit models, it is generally believed that the distributed parameters (capacitance, inductance, resistance and conductance) along the line are equal everywhere, that is, a uniform transmission line. Take a small length element dx at X of the long line, calculate the circuit parameters of the dx segment, establish a differential equation about the distance x, and solve the differential equation to obtain the voltage and current response at any position. However, the actual submarine cable cannot be a uniform transmission line. The leakage of the submarine cable is different at the place with the bracket and the place without the bracket. Between each span, the sag caused by the deadweight of the conductor also changes the uniformity of the distribution of the transmission line conductivity. Summary of the invention

[0005] The purpose of the present invention is to provide a method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis. The submarine cable overvoltage calculation equivalent circuit model established by the present invention is more in line with engineering practice, can accurately reflect the actual situation of submarine cable overvoltage, and has a small amount of calculation and is simple to solve.

[0006] In order to solve the above technical problems, the present invention provides a technical solution as follows: a method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis, comprising the following steps:

[0007] S1. First, the cable is roughly divided into N mother sections according to the geometric distribution, and then each mother section is divided into several sub-sections, which are then connected in series to form an equivalent circuit model for submarine cable overvoltage calculation;

[0008] S2. The distributed parameters of each circuit section are calculated using the finite element method, and the optimal segmentation scheme is determined through an adaptive genetic algorithm. Finally, the optimal equivalent circuit model for submarine cable overvoltage calculation is established.

[0009] The above-mentioned method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis establishes a reference circuit model. Each sub-segment of the reference circuit model contains M segmentation points, with a total of M×N sub-segmentation points. Whether the equivalent circuit model retains each sub-segmentation point is encoded 0-1, 1 for yes and 0 for no. Then, the calculation error between the equivalent circuit model and the reference circuit model is used as the objective function, and an adaptive genetic algorithm is used for optimization to determine the optimal segmentation scheme, and the optimal submarine cable overvoltage calculation equivalent circuit model is established according to the optimal segmentation scheme.

[0010] The adaptive multi-segment distributed parameter circuit model establishment method for the submarine cable performance analysis mentioned above establishes an equivalent circuit model C according to the number of segments N, wherein the segment points in the equivalent circuit model C are used as key points, the kth segment in the equivalent circuit model is marked as [k-1, k], and the length of the kth segment is L k ;

[0011] When establishing the reference circuit model C', the reference circuit model C' includes all key points of the equivalent circuit model C, and each sub-segment of the reference circuit model C' is equally divided into M segments, and the segmentation points in the reference circuit model C' are used as sub-key points.

[0012] The aforementioned method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis uses a genetic algorithm to determine the optimal segmentation scheme to establish an optimal submarine cable overvoltage calculation equivalent circuit model. The specific steps are as follows:

[0013] S2.1, Chromosome encoding: Whether each sub-key point is retained is taken as a decision variable, which is 1 if retained and 0 if not retained. The decision variable is binary encoded, and the chromosome formed by the encoding represents a circuit structure;

[0014] S2.2, Initialize the population: Use the random method, that is, for a certain bit of a bit string, the computer generates a random number in the interval (0,1). If the random number is greater than or equal to 0.5, the bit is 1, otherwise it is 0;

[0015] S2.3. Calculate the fitness function: use the finite element method to calculate the circuit parameters of each sub-segment of the chromosome corresponding circuit, determine the circuit model, apply lightning current excitation to the circuit, calculate the voltage amplitude to the ground of each key point [U1, ······, U2], and then calculate the voltage amplitude to the ground of each sub-key point of the reference circuit model [U'1, ······, U'2];

[0016] The fitness function is defined as:

[0017]

[0018] The larger the fitness function is, the closer the calculation result of the chromosome corresponding circuit model is to the reference circuit model and the more accurate it is.

[0019] S2.4. Consider the constraint function and modify the objective function: impose restrictions on the sub-key points. The constraint function is:

[0020]

[0021] Where R i represents the value of the i-th position of chromosome;

[0022] The meaning of the constraint function is: the total number of segments of the equivalent circuit model C shall not be greater than one-half of the number of segments of the reference circuit;

[0023] After applying the constraint function, the fitness function is modified:

[0024] F'=F×flag

[0025]

[0026] S2.5. Calculate the proportion diagram by the fitness function: In the interval of unit length, the length of the interval occupied by a bit string is proportional to the fitness of the bit string. The fitness proportion diagram is represented by a roulette wheel to calculate the selection probability. and expectations

[0027] S2.6, Selection: Randomly rotate the wheel, and the individual pointed by the arrow when the wheel is stable is selected as the seed;

[0028] S2.7, Crossover: The individuals selected in step S2.6 enter the mating process, using the adaptive crossover probability, calculated as follows:

[0029]

[0030] Where P cmin and P cmax Respectively represent the lower and upper limits of the crossover rate;

[0031] S2.8, mutation: Increasing the diversity of the population in the genetic algorithm enables the algorithm to jump out of the local optimum. The adaptive mutation operator is defined as follows:

[0032]

[0033] Where P mmin and P mmax They represent the lower and upper limits of the mutation rate respectively.

[0034] In the aforementioned method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis, in step S2.3, the circuit parameters of each sub-segment of the chromosome corresponding circuit are calculated using the finite element method, including the following parameter calculations:

[0035] A. Calculation of capacitance parameters:

[0036] W=C1U 2 / 2;

[0037] In the formula, W is the electrostatic energy of the system, and C1 is the capacitance between the two conductors;

[0038] B. Inductance parameter calculation:

[0039] Use the energy perturbation method to calculate the inductance. Assume that the current (i1, i2, ···, i j ,···,i n ), the relative capacity is W, and then the current has a small change (i1,i2,···,i j ±Δi j ,···,i n ), and find the corresponding energy W(i j ±Δi j ), and then assume that the current changes slightly (i1,i2,···,i k ±Δi k ,···,i n ), and find the corresponding energy W(i j ±Δi j ,i k ±Δi k ), and finally calculate the self-inductance L of the jth wire according to the following formula jj and the mutual inductance L between the jth and kth conductors jk ;

[0040]

[0041]

[0042] C. Resistance calculation:

[0043] R c =1 / (δαξ);

[0044] Where: R c is the resistance per unit length of the conductor; α is the circumference of the cross-section of the conductor turn; σ is the conductivity of the copper conductor; the penetration depth of the electromagnetic wave ω is the angular frequency of the transmission wave; the magnetic permeability of copper μ=μ0=4π×10 -7 ;

[0045] D. Calculation of earth conductivity:

[0046] In the submarine cable overvoltage model, the conductivity to ground includes the leakage conductivity and the conductivity caused by dielectric loss, which is determined by the conductivity of the solid / semi-conductive layer insulation medium:

[0047] δ=fε r tanδ / (1.8×10 12 );

[0048] Where: f is the transmission wave frequency; ε r is the relative dielectric constant; δ is the dielectric loss angle;

[0049] The conductivity to ground is calculated from the conductivity corresponding to the dielectric loss and the conductivity of the semiconducting layer.

[0050] Compared with the prior art, the present invention proposes a method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis. First, the cable is roughly divided into N mother sections according to the geometric distribution, and then each mother section is divided into several sub-segments, which are then connected in series to form an equivalent circuit model for submarine cable overvoltage calculation; the distributed parameters of each circuit section are calculated using the finite element method, and the optimal segmentation scheme is determined by an adaptive genetic algorithm, and finally the optimal submarine cable overvoltage calculation equivalent circuit model is established. Compared with the traditional lumped parameter model and the uniform transmission line model, the submarine cable overvoltage calculation equivalent circuit model finally determined by the method proposed in the present invention is more in line with engineering practice, can accurately reflect the actual situation of submarine cable overvoltage, and uses an adaptive genetic algorithm to optimize the number and position of segmentation points. Compared with the non-uniform transmission line model, the calculation amount is small and the solution is simple. The present invention is helpful to comprehensively evaluate the overvoltage level of submarine cables and provide a submarine cable insulation design scheme with high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the process of the present invention;

[0052] Figure 2 is a schematic diagram of an equivalent circuit model C of the present invention;

[0053] Figure 3 is a schematic diagram of a reference circuit model C' of the present invention;

[0054] Figure 4 This is a diagram of chromosome 1 and its corresponding circuit structure;

[0055] Figure 5 This is a diagram of chromosome 2 and its corresponding circuit structure;

[0056] Figure 6 It is a suitable ratio diagram. DETAILED DESCRIPTION

[0057] The present invention is further described below in conjunction with the embodiments and drawings, but they are not intended to limit the present invention.

[0058] Embodiment: A method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis, such as Figure 1 As shown, the following steps are included:

[0059] S1. First, roughly divide the cable into N main sections according to the geometric distribution, and then divide each main section into several sub-sections, and then connect them in series to form an equivalent circuit model for submarine cable overvoltage calculation; the submarine cable is non-uniformly distributed, and changes in the structure such as the bracket will cause changes in circuit parameters. The location of the bracket of the present invention is used as the main segmentation point of the submarine cable equivalent circuit to obtain a simple equivalent circuit model. An equivalent circuit model C is established based on the number of segments N, wherein the segmentation points in the equivalent circuit model C are used as key points, the kth segment in the equivalent circuit model is marked as [k-1, k], and the length of the kth segment is L k ;like Figure 2 As shown, there are three supports along the submarine cable, so the number of mother sections N is 4.

[0060] S2. The distributed parameters of each circuit section are calculated using the finite element method, and the optimal segmentation scheme is determined through an adaptive genetic algorithm. Finally, the optimal equivalent circuit model for submarine cable overvoltage calculation is established.

[0061] In this embodiment, a reference circuit model is established, and each sub-segment of the reference circuit model contains M segmentation points, with a total of M×N sub-segmentation points. Whether the equivalent circuit model retains each sub-segmentation point is encoded with 0-1, 1 for yes and 0 for no. Then, the calculation error between the equivalent circuit model and the reference circuit model is used as the objective function, and an adaptive genetic algorithm is used for optimization to determine the optimal segmentation scheme, and the optimal equivalent circuit model for submarine cable overvoltage calculation is established according to the optimal segmentation scheme.

[0062] When establishing the reference circuit model C', the reference circuit model C' includes all the key points of the equivalent circuit model C, and each sub-segment of the reference circuit model C' is equally divided into M segments, and the segmentation points in the reference circuit model C' are used as sub-key points. In this embodiment, when M is 3, the reference circuit can be obtained as follows Figure 3As shown. The sub-key points are {A1, A2, A3, B1, B2, B3, C1, C2 C3 D1, D2D3}. M is a custom parameter. Obviously, the larger M is, the more cable details the equivalent circuit can contain and the more accurate it is. The present invention uses C' as a reference circuit model, and believes that the closer the calculation result of circuit C is to C', the more accurate it is.

[0063] The present invention uses a genetic algorithm to determine the optimal segmentation scheme to establish an optimal submarine cable overvoltage calculation equivalent circuit model, and the specific steps are as follows:

[0064] S2.1, Chromosome encoding: Based on the key points of the reference circuit C', each sub-segment [k-1, k] has M more sub-segment points. Obviously, the more sub-segment points, the more accurate the circuit model. However, too many segments will make the circuit model complex and increase the calculation cost. Therefore, the present invention takes whether to retain each sub-key point as a decision variable, which is 1 if retained and 0 if not retained. The decision variable is binary encoded, and the chromosome formed by the encoding represents a circuit structure; based on Figure 3 The reference circuit model shown in the figure has a chromosome number of 12. Figure 4 and Figure 5 As shown, there are two types of chromosomes and their corresponding two circuit structures.

[0065] S2.2, Initialize the population: Use the random method, that is, for a certain bit of a bit string, the computer generates a random number in the interval (0,1). If the random number is greater than or equal to 0.5, the bit is 1, otherwise it is 0;

[0066] S2.3. Calculate the fitness function: For the chromosome, use the finite element method to calculate the circuit parameters of each sub-segment of the circuit corresponding to the chromosome, determine the circuit model, apply lightning current excitation to the circuit, calculate the voltage amplitude to the ground of each key point [U1, ······, U2], and then calculate the voltage amplitude to the ground of each sub-key point of the reference circuit model [U'1, ······, U'2];

[0067] The fitness function is defined as:

[0068]

[0069] The larger the fitness function is, the closer the calculation result of the chromosome corresponding circuit model is to the reference circuit model and the more accurate it is.

[0070] The circuit parameters of each sub-segment of the chromosome corresponding circuit are calculated using the finite element method, including the following parameter calculations:

[0071] A. Calculation of capacitance parameters:

[0072] W=C1U 2 / 2;

[0073] Where W is the electrostatic energy of the system, and C1 is the capacitance between the two conductors. Based on the relationship between energy and capacitance, the electrostatic field energy of the system can be calculated using numerical calculation methods, and the capacitance of the system can be calculated.

[0074] B. Inductance parameter calculation:

[0075] Use the energy perturbation method to calculate the inductance. Assume that the current (i1, i2, ···, i j ,···,i n ), the relative capacity is W, and then the current has a small change (i1,i2,···,i j ±Δi j ,···,i n ), and find the corresponding energy W(i j ±Δi j ), and then assume that the current changes slightly (i1,i2,···,i k ±Δi k ,···,i n ), and find the corresponding energy W(i j ±Δi j ,i k ±Δi k ), and finally calculate the self-inductance L of the jth wire according to the following formula jj and the mutual inductance L between the jth and kth conductors jk ;

[0076]

[0077]

[0078] C. In addition to the basic copper loss at the fundamental frequency, the skin effect and proximity effect at high frequencies are also considered. The simplified calculation of the skin effect (resistance calculation) is:

[0079] R c =1 / (δαξ);

[0080] Where: R c is the resistance per unit length of the conductor; α is the circumference of the cross-section of the conductor turn; σ is the conductivity of the copper conductor; the penetration depth of the electromagnetic wave ω is the angular frequency of the transmission wave; the magnetic permeability of copper μ=μ0=4π×10 -7 ;

[0081] D. Calculation of earth conductivity:

[0082] In the submarine cable overvoltage model, the conductivity to ground includes the leakage conductivity and the conductivity caused by dielectric loss, which is determined by the conductivity of the solid / semi-conductive layer insulation medium:

[0083] δ=fε rtanδ / (1.8×10 12 );

[0084] Where: f is the transmission wave frequency; ε r is the relative dielectric constant; δ is the dielectric loss angle;

[0085] The conductivity to ground is calculated from the conductivity corresponding to the dielectric loss and the conductivity of the semiconducting layer.

[0086] S2.4. Consider the constraint function and modify the objective function: Obviously, the more similar the number of segments between the equivalent circuit model C and the reference circuit model, that is, the more genes with the bit number 1, the smaller the fitness function. However, the more segments there are, the more complex the circuit is, and the higher the computational cost is. Therefore, restrictions are imposed on the sub-key points, and the constraint function is:

[0087]

[0088] Where R i represents the value of the i-th position of chromosome;

[0089] The meaning of the constraint function is: the total number of segments of the equivalent circuit model C shall not be greater than one-half of the number of segments of the reference circuit;

[0090] After applying the constraint function, the fitness function is modified:

[0091] F'=F×flag

[0092]

[0093] S2.5. Calculate the proportion diagram by the fitness function: In the interval of unit length, the interval length (or area) occupied by a bit string is proportional to the fitness of the bit string. The fitness proportion diagram is represented by a roulette wheel, as shown in Figure 6 As shown, calculate the selection probability and expectations

[0094] S2.6, Selection: Randomly rotate the wheel, and the individual pointed by the arrow when the wheel is stable is selected as the seed;

[0095] S2.7, Crossover: The individuals selected through step S2.6 enter the mating process. The genetic algorithm defines the mating probability (also called the crossover probability), which reflects the probability of two selected individuals mating. The two mating chromosomes randomly select the crossover point and exchange chromosomes to form a new chromosome, replacing the original "old" individual, while the non-mating individual remains unchanged. The chromosomes of the mating parents are exchanged with each other to produce two new chromosomes. In this embodiment, an adaptive crossover probability is used, and the calculation formula is as follows

[0096]

[0097] Where P cmin and P cmax Respectively represent the lower and upper limits of the crossover rate;

[0098] S2.8, mutation: Increasing the diversity of the population in the genetic algorithm enables the algorithm to jump out of the local optimum. If the mutation probability is too small, the diversity of the population cannot be changed well; if it is too large, it will destroy good gene fragments. Therefore, an adaptive mutation operator is used. After the above greedy crossover operator, the average fitness of the population is relatively high. For excellent individuals whose individual fitness is higher than the average fitness, a protection strategy should be adopted to retain them. At this time, the mutation probability should not be too large, and for individuals whose individual fitness is lower than the average fitness, they should be eliminated with a higher probability. The adaptive mutation operator in this embodiment is defined as follows:

[0099]

[0100] Where P mmin and P mmax They represent the lower and upper limits of the mutation rate respectively.

[0101] After the above steps, the optimal segmentation scheme is determined, and the optimal submarine cable overvoltage calculation equivalent circuit model is established based on the optimal segmentation scheme.

[0102] In summary, the present invention proposes a method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis. First, the cable is roughly divided into N mother segments according to geometric distribution, and then each mother segment is divided into several sub-segments, which are then connected in series to form an equivalent circuit model for submarine cable overvoltage calculation; the distributed parameters of each circuit segment are calculated using the finite element method, and the optimal segmentation scheme is determined by an adaptive genetic algorithm, and finally the optimal submarine cable overvoltage calculation equivalent circuit model is established. Compared with the traditional lumped parameter model and the uniform transmission line model, the submarine cable overvoltage calculation equivalent circuit model finally determined by the method proposed in the present invention is more in line with engineering practice, can accurately reflect the actual situation of submarine cable overvoltage, and uses an adaptive genetic algorithm to optimize the number and position of segmentation points. Compared with the non-uniform transmission line model, the calculation amount is small and the solution is simple. The present invention is helpful to comprehensively evaluate the overvoltage level of submarine cables and provide a submarine cable insulation design scheme with high reliability.

Claims

1. A method for establishing an adaptive multi-section distributed parameter circuit model for submarine cable performance analysis, characterized in that: The steps include: S1. First, the cable is roughly divided into N mother sections according to the geometric distribution, and then each mother section is divided into several sub-sections, which are then connected in series to form an equivalent circuit model for submarine cable overvoltage calculation; S2. Calculate the distribution parameters of each circuit segment using the finite element method, determine the optimal segmentation scheme using an adaptive genetic algorithm, and ultimately establish the optimal equivalent circuit model for submarine cable overvoltage calculation; By establishing a reference circuit model, each sub-segment of the reference circuit model contains M segmentation points, with a total of M×N sub-segmentation points. Whether the equivalent circuit model retains each sub-segmentation point is coded 0-1, 1 for yes, 0 for no. Then, the calculation error between the equivalent circuit model and the reference circuit model is used as the objective function, and the adaptive genetic algorithm is used for optimization to determine the optimal segmentation scheme. According to the optimal segmentation scheme, the optimal equivalent circuit model for submarine cable overvoltage calculation is established. The equivalent circuit model C is established according to the number of segments N, where the segmentation points in the equivalent circuit model C are used as key points, the kth segment in the equivalent circuit model is marked as [k-1, k], and the length of the kth segment is L k ; When establishing the reference circuit model C', the reference circuit model C' includes all the key points of the equivalent circuit model C, and each sub-segment of the reference circuit model C' is equally divided into M segments, and the segmentation points in the reference circuit model C' are used as sub-key points; The optimal segmentation scheme is determined by using genetic algorithm to establish the optimal equivalent circuit model for submarine cable overvoltage calculation. The specific steps are as follows: S2.1, Chromosome encoding: Whether each sub-key point is retained is taken as a decision variable, which is 1 if retained and 0 if not retained. The decision variable is binary encoded, and the chromosome formed by the encoding represents a circuit structure; S2.2, Initialize the population: Use the random method, that is, for a certain bit of a bit string, the computer generates a random number in the interval (0,1). If the random number is greater than or equal to 0.5, the bit is 1, otherwise it is 0; S2.

3. Calculate the fitness function: use the finite element method to calculate the circuit parameters of each sub-segment of the chromosome corresponding circuit, determine the circuit model, apply lightning current excitation to the circuit, calculate the voltage amplitude to the ground of each key point [U1, ······, U2], and then calculate the voltage amplitude to the ground of each sub-key point of the reference circuit model [U'1, ······, U'2]; The fitness function is defined as: The larger the fitness function is, the closer the calculation result of the chromosome corresponding circuit model is to the reference circuit model and the more accurate it is. S2.

4. Consider the constraint function and modify the objective function: impose restrictions on the sub-key points. The constraint function is: Where R i represents the value of the i-th position of chromosome; The meaning of the constraint function is: the total number of segments of the equivalent circuit model C shall not be greater than one-half of the number of segments of the reference circuit; After applying the constraint function, the fitness function is modified: F'=F×flag S2.

5. Calculate the proportion diagram by the fitness function: In the interval of unit length, the length of the interval occupied by a bit string is proportional to the fitness of the bit string. The fitness proportion diagram is represented by a roulette wheel to calculate the selection probability. and expectations S2.6, Selection: Randomly rotate the wheel, and the individual pointed by the arrow when the wheel is stable is selected as the seed; S2.7, Crossover: The individuals selected in step S2.6 enter the mating process, using an adaptive crossover probability, calculated as follows Where P cmin and P cmax Respectively represent the lower and upper limits of the crossover rate; S2.8, mutation: Increasing the diversity of the population in the genetic algorithm enables the algorithm to jump out of the local optimum. The adaptive mutation operator is defined as follows: Where P mmin and P mmax They represent the lower and upper limits of the mutation rate respectively.

2. The method for establishing an adaptive multi-segment distributed parameter circuit model for submarine cable performance analysis according to claim 1, characterized in that: In step S2.3, the circuit parameters of each sub-segment of the chromosome corresponding circuit are calculated using the finite element method, including the following parameter calculations: A. Calculation of capacitance parameters: W=C1U 2 / 2; In the formula, W is the electrostatic energy of the system, and C1 is the capacitance between the two conductors; B. Inductance parameter calculation: Use the energy perturbation method to calculate the inductance. Assume that the current (i1, i2, ···, i j ,···,i n ), the relative capacity is W, and then the current has a small change (i1,i2,···,i j ±Δi j ,···,i n ), and find the corresponding energy W(i j ±Δi j ), and then assume that the current changes slightly (i1,i2,···,i k ±Δi k ,···,i n ), and find the corresponding energy W(i j ±Δi j ,i k ±Δi k ), and finally calculate the self-inductance L of the jth wire according to the following formula jj and the mutual inductance L between the jth and kth conductors jk ; C. Resistance calculation: R c =1 / (dax); Where: R c is the resistance per unit length of the conductor; α is the circumference of the cross-section of the conductor turn; σ is the conductivity of the copper conductor; the penetration depth of the electromagnetic wave ω is the angular frequency of the transmission wave; the magnetic permeability of copper μ=μ0=4π×10 -7 ; D. Calculation of earth conductivity: In the submarine cable overvoltage model, the conductivity to ground includes the leakage conductivity and the conductivity caused by dielectric loss, which is determined by the conductivity of the solid / semi-conductive layer insulation medium: δfε r tanδ / (1.8×1 12 )4 Where: f is the transmission wave frequency; ε r is the relative dielectric constant; δ is the dielectric loss angle; The conductivity to ground is calculated from the conductivity corresponding to the dielectric loss and the conductivity of the semiconducting layer.

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