Method for determining initial value of surface charge density of conductor based on two norm and terminal

Abstract

The application provides a two-norm-based conductor surface charge density initial value determination method and a terminal. The method comprises the following steps: determining the deviation degree between each line parameter group recorded in a line parameter set constructed in advance and the standardized calculation parameter vector, generating a conductor surface charge density pilot value corresponding to the DC power transmission line according to the conductor surface charge density initial value corresponding to the line parameter group with the minimum deviation degree; iteratively calculating the conductor surface charge density and the DC resultant electric field corresponding to the DC power transmission line by using the generated conductor surface charge density pilot value; and terminating the iteration when the full-field charge density is stable and the Kaptzov assumption is met, and determining the positive and negative polarity conductor surface charge densities determined in the current iteration as the positive and negative polarity conductor surface charge density initial values corresponding to the DC power transmission line. Thus, the calculation efficiency is high, and the usability is strong.

Description

Technical Field

[0001] This invention relates to the field of DC composite electric field calculation technology, and more specifically, to a method and terminal for determining the initial value of surface charge density of a conductor based on the second norm. Background Technology

[0002] With China facing a severe shortage of land resources, selecting power line corridors is becoming increasingly difficult. Power lines are increasingly located near densely populated areas such as residential areas, which can easily lead to electromagnetic environment problems. Among these issues, the composite electric field, as a significant environmental factor, has attracted widespread attention from power and environmental protection departments and has become a crucial factor in determining power line corridors and tower dimensions.

[0003] Therefore, in the early stages of project construction, it is necessary to conduct a large number of composite electric field calculations under different parameters to ensure the environmental friendliness of the transmission line.

[0004] In the calculation of the composite electric field of a DC transmission line (hereinafter referred to as the DC composite electric field), the selection of the initial value of the surface charge density of the conductor is very important. An inappropriate initial value may even lead to the calculation failing to converge, while an appropriate initial value will significantly improve the calculation efficiency.

[0005] Therefore, it is necessary to propose a technical solution for selecting the initial value of the surface charge density of the conductor for DC composite electric field calculation, so as to provide technical support for the rapid convergence of the DC composite electric field calculation process. Summary of the Invention

[0006] In view of this, the present invention proposes a method and terminal for determining the initial value of surface charge density of conductors based on the second norm, aiming to solve the problem that the selection of the initial value of surface charge density of conductors is difficult in the prior art, which leads to low efficiency in the calculation of DC composite electric field.

[0007] In a first aspect, this application provides a method for determining the initial value of the surface charge density of a conductor based on the second norm, including:

[0008] Generate a standardized calculation parameter vector corresponding to the DC transmission line;

[0009] Determine the degree of deviation between each line parameter group recorded in the pre-constructed line parameter set and the standardized calculation parameter vector, and generate the lead value of the conductor surface charge density corresponding to the DC transmission line based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation.

[0010] Using the generated leading value of the conductor surface charge density, the conductor surface charge density and DC composite electric field corresponding to the DC transmission line are calculated iteratively; when the charge density in the entire field is stable and satisfies the Kaptzov assumption, the iteration is terminated, and the positive and negative polarity conductor surface charge densities determined in the current iteration are determined as the initial values ​​of the positive and negative polarity conductor surface charge densities corresponding to the DC transmission line.

[0011] Furthermore, the generation of the standardized calculation parameter vector corresponding to the DC transmission line includes:

[0012] Obtain the calculation parameter set corresponding to the DC transmission line;

[0013] Arrange the parameters in the calculation parameter group into a calculation parameter vector according to a preset order;

[0014] The computational parameter vector is standardized to obtain the standardized computational parameter vector.

[0015] Furthermore, the parameters in the calculation parameter group corresponding to the DC transmission line include:

[0016] Voltage level, number of conductor splits, split spacing, sub-conductor radius, conductor height, conductor pole spacing, conductor roughness coefficient;

[0017] The standardization process for the computational parameter vector, resulting in the standardized computational parameter vector, includes:

[0018] A reference vector is constructed with a voltage level of 100kV, a conductor split number of 10, a split spacing of 500mm, a sub-conductor radius of 15mm, a conductor height of 10m, a conductor pole spacing of 20m, and a conductor roughness coefficient of 1.

[0019] The quotient obtained by dividing each element in the computational parameter vector by each element in the constructed reference vector is used as each element in the standardized computational parameter vector.

[0020] Furthermore, determining the degree of deviation between each group of line parameters recorded in the pre-constructed line parameter set and the standardized calculated parameter vector includes:

[0021] The standardized vectors corresponding to each line parameter group recorded in the pre-constructed line parameter set and the L2 norm of the standardized calculated parameter vector indicate the degree of deviation between each line parameter group and the standardized calculated parameter vector.

[0022] Further, the step of generating a leading value for the surface charge density of the conductor corresponding to the DC transmission line based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation includes:

[0023] Determine the minimum value between the standardized vector corresponding to each group of line parameters recorded in the pre-constructed line parameter set and the L2 norm of the standardized calculated parameter vector;

[0024] The line parameter group corresponding to the minimum value is determined as the line parameter group with the smallest deviation.

[0025] The relative magnitudes of the minimum value and the preset L2 distance limit are compared, and a lead value of the conductor surface charge density corresponding to the DC transmission line is generated based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation.

[0026] Furthermore, the initial value of the surface charge density of the conductor.

[0027] When the minimum value is not greater than the preset L2 distance limit, the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation is determined as the leading value of the conductor surface charge density corresponding to the DC transmission line.

[0028] When the minimum value is greater than the preset L2 distance limit, the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation is corrected according to the empirical formula, and the corrected initial value of the conductor surface charge density is determined as the leading value of the conductor surface charge density corresponding to the DC transmission line.

[0029] Furthermore, the initial value of the surface charge density of the conductor.

[0030] The initial values ​​of the surface charge density of the positive and negative polarity conductors corresponding to the line parameter set with the smallest deviation are corrected according to the following empirical formula:

[0031] Where ε0 is the vacuum permittivity, U0 is the corona initiation voltage of the conductor, E0 is the corona initiation field strength, and E g Let U be the electric field strength directly below the conductor, U be the operating voltage of the conductor, r be the radius of the sub-conductor, and h be the height of the conductor.

[0032] Among them, the positive dizziness field strength E 0+ Determined according to the following formula:

[0033]

[0034] Taking on the burden of dizziness and strong E 0- Determined according to the following formula:

[0035]

[0036] The relative density of air is determined by the following formula: δ=pT0 / (p0T);

[0037] Wherein, the current air pressure is p, the standard air pressure is p0; the current temperature is T, the standard temperature is T0; and m is the conductor roughness coefficient.

[0038] Furthermore, the initial values ​​of the surface charge density of the conductor include:

[0039] An overhead transmission line model is established, which includes the Poisson equation and the current continuity equation.

[0040] Based on the generated surface charge density precursor value corresponding to the DC transmission line, the Poisson equation and the current continuity equation are calculated using the upstream finite element method until the charge density in the entire field stabilizes, thus obtaining the maximum value E of the electric field intensity on the surface of the positive polarity conductor. max+ and the maximum value E of the electric field strength on the surface of the negative polarity conductor. max- and the surface charge density of positive and negative polarities;

[0041] The maximum values ​​of the electric field strength on the surface of the positive polarity conductor and the maximum values ​​of the electric field strength on the surface of the negative polarity conductor are respectively compared with the positive halo field strength E. 0+ and the strong E of the field of dizziness 0- Compare and generate the relative error of the field strength;

[0042] If the relative error of the field strength is less than the specified limit of the field strength, the positive and negative polarity surface charge density determined when the charge density of the entire field is stable is determined as the initial value of the positive and negative polarity conductor surface charge density corresponding to the DC transmission line.

[0043] If the relative error of the electric field strength is not less than the specified limit of the electric field strength, then the positive and negative polarity surface charge densities determined when the charge density of the entire field is stable shall be corrected according to the following formula:

[0044]

[0045] Where μ is set to 2.1, the field strength limit is 0.005, and n is the number of iterations.

[0046] In the next iteration, the charge density and the electric field strength on the surface of the conductor are updated using the upstream finite element method until the relative error of the electric field strength on the surface of the conductor, which is determined when the charge density in the whole field is stable, meets the specified limit of the electric field strength.

[0047] When the relative error of the electric field strength meets the specified limit of the electric field strength, the positive and negative polarity surface charge density determined when the charge density of the entire field is stable is determined as the initial value of the positive and negative polarity conductor surface charge density corresponding to the DC transmission line.

[0048] In a second aspect, this application provides a terminal, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement any one of the methods described in the first aspect.

[0049] Thirdly, this application provides a computer storage medium storing computer-executable instructions for performing the method described in the first aspect.

[0050] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0051] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0052] Figure 1 This is a flowchart illustrating the method for determining the initial value of the surface charge density of a conductor based on the second norm according to an embodiment of this application.

[0053] Figure 2 This is a flowchart illustrating another embodiment of the present application of a method for determining the initial value of surface charge density of a conductor based on the second norm;

[0054] Figure 3 This is a schematic diagram of the circuit for a certain engineering example in this application;

[0055] Figure 4 This is a schematic diagram showing the L2 distance between the standardized calculation parameter vector of a DC transmission line in a certain transmission line project in this application embodiment and the standardized vectors corresponding to each group of line parameters recorded in the line parameter set;

[0056] Figure 5 This is a schematic diagram comparing the iterative process for determining the surface charge density of the conductor in this embodiment with the iterative process of the traditional calculation method.

[0057] Figure 6 This is a schematic diagram of the terminal components for implementing the method for determining the initial value of surface charge density of a conductor based on the second norm in an embodiment of the present invention. Detailed Implementation

[0058] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features described herein can be combined with each other.

[0059] Ultra-high voltage (UHV) power transmission refers to the transmission of electrical energy using direct current (DC) of ±800kV and above. UHV power transmission was developed based on extra-high voltage (EHV) power transmission, and its purpose remains to further improve transmission capacity, realize high-power medium- and long-distance power transmission, and achieve long-distance power system interconnection.

[0060] China is accelerating the construction of ultra-high-voltage (UHV) power transmission projects. For example, from 2021 to 2025, it plans to build 24 AC and 14 DC UHV lines to effectively solve the problems of high-proportion renewable energy grid connection and large-scale inter-provincial and inter-regional power allocation, and fully support the energy transition.

[0061] 220kV and above UHVDC overhead lines typically use multi-split conductors. This is because multi-split conductors can increase the equivalent radius of the conductor, reducing corona loss or line reactance. The number of splits, n, in multi-split conductors is usually 2, 3, 4, 5, 6, or 8. Figure 3 In a ±800kV DC transmission line shown, the pole conductors (positive or negative) are arranged horizontally, and 6-split conductors (the number of conductor splits N is 6) are used. The sub-conductor model is JL1 / G1A-1250 / 70, the sub-conductor diameter is 47.4mm, and the split spacing is 500mm.

[0062] When overhead power lines carry high voltage, if the electric field strength on the conductor surface exceeds the breakdown strength of air (e.g., the corona field strength), the air surrounding the conductor is ionized, resulting in a partial discharge phenomenon known as corona discharge. Corona discharge on high-voltage direct current (HVDC) transmission lines generates charged ions. These ions are pushed towards the ground under the influence of the electric field, causing the ground field strength to increase to several times the nominal electric field generated by the surface charge of the HVDC transmission line conductor and its induced charges on the ground. Academically, this type of electric field with moving charges in the space surrounding the transmission line is called an ion flow field; in engineering, it is called a composite electric field.

[0063] To ensure the safety of personnel activities below the transmission line, the ion flow field or composite electric field near the ground must be controlled below certain limits. Therefore, environmental assessments of DC transmission lines typically include indicators such as composite electric field strength, ion flow density, audible noise, and radio interference.

[0064] Currently, the calculation of the composite electric field intensity requires a double iteration of charge density and electric field intensity, resulting in low computational efficiency and a long calculation time in the early design phase of engineering projects. On the other hand, in the calculation of the composite electric field of DC transmission lines (hereinafter referred to as DC composite electric field), the selection of the initial value of the charge density on the conductor surface is very important. An inappropriate initial value may even lead to the calculation failing to converge, while an appropriate initial value will significantly improve the computational efficiency.

[0065] Currently, the initial value of the surface charge density of conductors is selected based solely on engineering experience, which requires repeated trial and error, making it difficult and resulting in low efficiency in calculating the composite electric field of DC transmission lines.

[0066] To address the problem of predicting electric field intensity near actual transmission lines, this invention provides a method for selecting the initial value of conductor surface charge density based on the second norm. The method is accurate, efficient, and easy to use, and can provide technical support for the rapid prediction of DC composite electric field in engineering design.

[0067] like Figure 1 As shown, the method for determining the initial value of conductor surface charge density based on the second norm in this application embodiment is used to calculate the DC composite electric field of a transmission line, and includes the following steps S10 to S30:

[0068] S10: Generate the standardized calculation parameter vector corresponding to the DC transmission line;

[0069] S20: Determine the degree of deviation between each line parameter group recorded in the pre-constructed line parameter set and the standardized calculation parameter vector, and generate the lead value of the conductor surface charge density corresponding to the DC transmission line based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation.

[0070] S30: Using the generated leading value of the conductor surface charge density, iteratively calculate the conductor surface charge density and DC composite electric field corresponding to the DC transmission line; when the charge density in the entire field is stable and satisfies the Kaptzov assumption, terminate the iteration, and determine the positive and negative polarity conductor surface charge density determined in the current iteration as the initial value of the positive and negative polarity conductor surface charge density corresponding to the DC transmission line.

[0071] Specifically, in step S10 above, generating the standardized calculation parameter vector corresponding to the DC transmission line includes:

[0072] Obtain the calculation parameter set corresponding to the DC transmission line;

[0073] Arrange the parameters in the calculation parameter group into a calculation parameter vector according to a preset order;

[0074] The computational parameter vector is standardized to obtain the standardized computational parameter vector.

[0075] Specifically, the parameters in the calculation parameter group corresponding to the DC transmission line include:

[0076] Voltage level, number of conductor splits, split spacing, sub-conductor radius, conductor height, conductor pole spacing, conductor roughness coefficient;

[0077] The standardization process for the computational parameter vector, resulting in the standardized computational parameter vector, includes:

[0078] A reference vector is constructed with a voltage level of 100kV, a conductor split number of 10, a split spacing of 500mm, a sub-conductor radius of 15mm, a conductor height of 10m, a conductor pole spacing of 20m, and a conductor roughness coefficient of 1.

[0079] The quotient obtained by dividing each element in the computational parameter vector by each element in the constructed reference vector is used as each element in the standardized computational parameter vector.

[0080] Specifically, in step S20 above, determining the degree of deviation between each group of line parameters recorded in the pre-constructed line parameter set and the standardized calculated parameter vector includes:

[0081] The standardized vectors corresponding to each line parameter group recorded in the pre-constructed line parameter set and the L2 norm of the standardized calculated parameter vector indicate the degree of deviation between each line parameter group and the standardized calculated parameter vector.

[0082] Specifically, the step of generating a leading value for the conductor surface charge density corresponding to the DC transmission line based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation includes:

[0083] Determine the minimum value between the standardized vector corresponding to each group of line parameters recorded in the pre-constructed line parameter set and the L2 norm of the standardized calculated parameter vector;

[0084] The line parameter group corresponding to the minimum value is determined as the line parameter group with the smallest deviation.

[0085] The relative magnitudes of the minimum value and the preset L2 distance limit are compared, and a lead value of the conductor surface charge density corresponding to the DC transmission line is generated based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation.

[0086] Specifically, when the minimum value is not greater than the preset L2 distance limit, the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation is determined as the leading value of the conductor surface charge density corresponding to the DC transmission line.

[0087] When the minimum value is greater than the preset L2 distance limit, the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation is corrected according to the empirical formula, and the corrected initial value of the conductor surface charge density is determined as the leading value of the conductor surface charge density corresponding to the DC transmission line.

[0088] Specifically, the initial values ​​of the surface charge density of the positive and negative polarity conductors corresponding to the line parameter set with the smallest deviation are corrected according to the following empirical formula:

[0089] Where ε0 is the vacuum permittivity, U0 is the corona initiation voltage of the conductor, E0 is the corona initiation field strength, and E g Let U be the electric field strength directly below the conductor, U be the operating voltage of the conductor, r be the radius of the sub-conductor, and h be the height of the conductor.

[0090] Among them, the positive dizziness field strength E 0+ Determined according to the following formula:

[0091]

[0092] Taking on the burden of dizziness and strong E 0- Determined according to the following formula:

[0093]

[0094] The relative density of air is determined by the following formula: δ=pT0 / (p0T);

[0095] Wherein, the current air pressure is p, the standard air pressure is p0; the current temperature is T, the standard temperature is T0; and m is the conductor roughness coefficient.

[0096] Specifically, step S30 above includes:

[0097] An overhead transmission line model is established, which includes the Poisson equation and the current continuity equation.

[0098] Based on the generated surface charge density precursor value corresponding to the DC transmission line, the Poisson equation and the current continuity equation are calculated using the upstream finite element method until the charge density in the entire field stabilizes, thus obtaining the maximum value E of the electric field intensity on the surface of the positive polarity conductor. max+ The maximum value E of the electric field strength on the surface of the negative polarity conductor. max- and the surface charge density of positive and negative polarities;

[0099] The maximum values ​​of the electric field strength on the surface of the positive polarity conductor and the maximum values ​​of the electric field strength on the surface of the negative polarity conductor are respectively compared with the positive halo field strength E. 0+ and the strong E of the field of dizziness 0- Compare and generate the relative error of the field strength;

[0100] If the relative error of the field strength is less than the specified limit of the field strength, the positive and negative polarity surface charge density determined when the charge density of the entire field is stable is determined as the initial value of the positive and negative polarity conductor surface charge density corresponding to the DC transmission line.

[0101] If the relative error of the electric field strength is not less than the specified limit of the electric field strength, then the positive and negative polarity surface charge densities determined when the charge density of the entire field is stable shall be corrected according to the following formula:

[0102]

[0103] Where μ is set to 2.1, the field strength limit is 0.005, and n is the number of iterations.

[0104] In the next iteration, the charge density and the electric field strength on the surface of the conductor are updated using the upstream finite element method until the relative error of the electric field strength on the surface of the conductor, which is determined when the charge density in the whole field is stable, meets the specified limit of the electric field strength.

[0105] When the relative error of the electric field strength meets the specified limit of the electric field strength, the positive and negative polarity surface charge density determined when the charge density of the entire field is stable is determined as the initial value of the positive and negative polarity conductor surface charge density corresponding to the DC transmission line.

[0106] like Figure 2 As shown, another embodiment of this application describes a method for determining the initial value of the surface charge density of a conductor based on the second norm, used to calculate the DC composite electric field of a transmission line, including steps 1 to 5.

[0107] Step 1: Obtain the calculation parameter group corresponding to the DC transmission line, and arrange the parameters in the calculation parameter group into a calculation parameter vector according to a preset order; perform standardization processing on the calculation parameter vector to obtain the standardized calculation parameter vector.

[0108] Among them, the parameters in the calculation parameter group corresponding to DC transmission lines include: voltage level U, number of conductor splits N, split spacing l, sub-conductor radius r, conductor height above ground (i.e., conductor height h), conductor pole spacing d (the straight-line distance between the positive and negative conductors along the horizontal direction), and conductor roughness coefficient m.

[0109] In some embodiments, the computation parameter vector includes a seven-element numerical vector (U,N,l,r,h,d,m). T The parameters are arranged in the following order within the seven-element numerical vector: voltage level U, number of conductor splits N, split spacing l, sub-conductor radius r, conductor height h, conductor pole spacing d, and conductor roughness coefficient m.

[0110] This should be understood as meaning that the order of the seven parameters within the seven-element numerical vector corresponding to the calculation parameter vector can be flexibly adjusted without affecting the calculation result of the initial charge density value.

[0111] The above vectorization of the parameters corresponding to DC transmission lines realizes parameter structuring, which is beneficial to improving the calculation efficiency in subsequent steps.

[0112] In some embodiments, the values ​​corresponding to voltage level, number of conductor splits, split spacing, sub-conductor radius, conductor height, conductor pole spacing, and conductor roughness coefficient are read from the design data in the early stage of the transmission line project, and structured into a seven-element numerical vector (U,N,l,r,h,d,m). T .

[0113] Specifically, the six parameters—voltage level, number of conductor splits, split spacing, sub-conductor radius, conductor height, and conductor pole spacing—are inherent parameters of DC transmission lines within power corridors or line corridors in transmission line engineering. The conductor roughness coefficient is a crucial parameter determining the corona field strength. All seven parameters are indispensable in the calculation of the DC composite electric field. Once the values ​​or ranges of these parameters are obtained, the calculation of the DC composite electric field can begin.

[0114] Specifically, in the process of calculating the DC composite electric field, the overhead line is modeled, an overhead line model is established, and the DC composite electric field can be calculated using the values ​​of each parameter. Refer to the steps described later, which will not be repeated here.

[0115] First, among the seven parameters mentioned above, the voltage level has the most significant impact on the surface charge density of a conductor. The surface charge density of a conductor varies greatly depending on the voltage level at which it operates. Common DC voltage levels are: ±220kV, ±500kV, ±660kV, ±800kV, and ±1100kV.

[0116] Secondly, among the seven parameters mentioned above, the parameters that have a more significant impact on the surface charge density of the conductor include the sub-conductor radius, the number of splits, and the split spacing. The sub-conductor radius of a multi-split conductor typically ranges from 15 mm to 23.7 mm; the number of splits is typically any one of the following: 4, 6, or 8; and the split spacing is typically any one of the following: 400 mm, 450 mm, 500 mm, or 550 mm.

[0117] Furthermore, among the seven parameters mentioned above, the parameters that have a more significant impact on the surface charge density of the conductor include conductor height and electrode spacing. The conductor height of UHV transmission lines is typically above 25m, while that of extra-high voltage transmission lines is typically around 15m. The electrode spacing of both UHV and extra-high voltage transmission lines is usually between 12m and 22m, with relatively little variation.

[0118] Finally, among the seven parameters mentioned above, the conductor roughness coefficient is an important parameter that determines the corona field strength. It can be measured or calculated and is usually selected based on engineering experience, such as 0.47.

[0119] In some embodiments, after arranging the parameters within the calculation parameter group into a calculation parameter vector according to a preset order, the standardization process for the calculation parameter vector includes:

[0120] (100kV, 10, 500mm, 15mm, 10m, 20m, 1) T Using the reference vector as the base vector, the quotient obtained by dividing each element of the computational parameter vector by the corresponding element of the reference vector is used as the element of the standardized computational parameter vector after standardization. The standardized computational parameter vector is denoted as (x1,x2,x3,x4,x5,x6,x7). T .

[0121] Each element in the reference vector is a parameter reference quantity. That is, the parameter reference quantities corresponding to voltage level, number of conductor splits, split spacing, sub-conductor radius, conductor height, conductor pole spacing, and conductor roughness coefficient are 100kV, 10, 500mm, 15mm, 10m, 20m, and 1, respectively.

[0122] The reference values ​​for voltage level, number of conductor splits, split spacing, sub-conductor radius, conductor height, conductor pole spacing, and conductor roughness coefficient are 100kV, 10, 500mm, 15mm, 10m, 20m, and 1, respectively. The voltage level uses 100kV, the sub-conductor radius uses 15mm, and the conductor height uses 10m, which are relatively small values ​​within the range. The other parameters, such as the number of conductor splits, split spacing, and conductor pole spacing, use intermediate values ​​within the range.

[0123] Referring to the foregoing explanation, the seven parameters mentioned above have varying degrees of influence on the surface charge density of the conductor. For parameters with a significant impact, a smaller value within their range is selected as the baseline value; for parameters with a smaller impact, a slightly larger value within their range is selected as the baseline value. This approach helps to reflect the different degrees of influence of each parameter on the surface charge density of the conductor.

[0124] That is, the above reference vector is (100kV, 10, 500mm, 15mm, 10m, 20m, 1). T This helps to demonstrate the degree of influence of the above parameters on the surface charge density of the conductor.

[0125] Accordingly, x1 = U / 100kV. Referring to the foregoing explanation, the DC voltage level U is any of the following: ±220kV, ±500kV, ±660kV, ±800kV, and ±1100kV. Therefore, the value of x1 is greater than 2 and less than 15.

[0126] Accordingly, x2 = N / 10. Referring to the foregoing explanation, the number of splits N can be any of the following: 4, 6, or 8. Thus, the value of x2 is greater than 0 and less than 1.

[0127] Accordingly, x3 = l / 500. Referring to the foregoing explanation, the splitting distance l can be any of the following: 400mm, 450mm, 500mm, and 550mm. Thus, the value of x3 is greater than 0 and less than or equal to 1.1.

[0128] Accordingly, x4 = r / 15. Referring to the foregoing explanation, the value of the sub-conductor radius r ranges from 15mm to 23.7mm. Thus, the value of x4 is greater than 0 and less than 1.6.

[0129] Accordingly, x5 = h / 10. Referring to the aforementioned explanation, the value of the conductor height includes 25m (for ultra-high voltage) and 15m (for extra-high voltage). Thus, the value of x5 is greater than 0 and less than 1.5 or greater than 0 and less than 2.5.

[0130] Accordingly, x6 = d / 20. Referring to the aforementioned explanation, the pole spacing of UHV or EHV transmission lines is usually between 12m and 22m. Thus, the value of x6 is greater than 0.6 and less than 1.1.

[0131] Accordingly, we have x7 = m / 1. Referring to the above explanation, the roughness coefficient is usually selected based on engineering experience, such as taking 0.47. Thus, the range of x7 is greater than 0 and less than 1.

[0132] Thus, after standardization, the absolute values ​​of each element in the standardized calculation parameter vector can directly reflect the degree of influence of the parameter on the surface charge density of the conductor. That is, after standardization, the absolute values ​​of parameters with smaller influence are smaller, and the absolute values ​​of parameters with larger influence are larger.

[0133] Step 2: Determine the degree of deviation between each group of line parameters recorded in the pre-constructed line parameter set and the standardized calculation parameter vector after standardization processing.

[0134] In some embodiments, the standardized vectors corresponding to each line parameter group recorded in the pre-built line parameter set and the L2 norm of the standardized calculated parameter vector are used to indicate the degree of deviation between each line parameter group and the standardized calculated parameter vector.

[0135] Specifically, the L2 distance between the standardized calculation parameter vector and the standardized vector corresponding to each group of line parameters recorded in the pre-constructed line parameter set is calculated one by one. In this way, the L2 distance is used to indicate the degree of deviation between the two vectors, which is computationally efficient.

[0136] It should be understood that the pre-constructed line parameter set contains data for calculating the DC composite electric field from multiple line parameter groups, including: the values ​​of each parameter in the line parameter group, the standardized vector corresponding to the line parameter group, and the initial values ​​of the surface charge density of the positive and negative polarity conductors corresponding to the line parameter group. The steps for standardizing the values ​​of each parameter in the line parameter group and the reference vector used are described above and will not be repeated here. The initial values ​​of the surface charge density of the positive and negative polarity conductors corresponding to the line parameter group can be determined by conventional calculation methods or by the method described in the embodiments of this application, and will not be repeated here.

[0137] Step 3: Determine the line parameter set with the smallest deviation from the standardized calculation parameter vector; determine the initial values ​​of the surface charge density of the positive and negative polarity conductors recorded in the line parameter set that correspond to the line parameter set with the smallest deviation.

[0138] Specifically, determining the line parameter set that deviates least from the standardized calculation parameter vector includes:

[0139] Determine the minimum value between the standardized vector corresponding to each group of line parameters recorded in the pre-constructed line parameter set and the L2 norm of the standardized calculated parameter vector;

[0140] The line parameter group corresponding to the minimum value is determined as the line parameter group with the smallest deviation.

[0141] Thus, the line parameter set with the smallest L2 distance to the standardized calculation parameter vector is obtained.

[0142] The above method uses the L2 norm formula to calculate the L2 norm distance between the standardized calculation parameter vector and the standardized vector corresponding to each line parameter group recorded in the line parameter set. The L2 norm distance is used to indicate the degree of deviation between the calculated parameter vector and each line parameter group recorded in the pre-constructed line parameter set. The method is convenient, efficient, and has good discrimination.

[0143] The above method, by traversing the various line parameter sets recorded in the line parameter set, obtains the global optimal solution, which is beneficial for rapid convergence.

[0144] Specifically, a preliminary value for the surface charge density of the conductor corresponding to the DC transmission line is generated based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation, including:

[0145] Determine the initial values ​​of the surface charge density of the positive and negative polarity conductors corresponding to the line parameter group with the smallest deviation from the line parameter set recorded in the line parameter set;

[0146] The relative magnitudes of the minimum value and the preset L2 distance limit are compared, and a lead value of the conductor surface charge density corresponding to the DC transmission line is generated based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation.

[0147] Specifically, in step 3, determining the line parameter set with the smallest deviation from the standardized calculation parameter vector includes:

[0148] The data for calculating the DC composite electric field is read from the line parameter set, which contains the data of each line parameter group recorded in the line parameter set. That is, a standardized vector (a1,a2,a3,a4,a5,a6,a7) after standardization. T Surface charge density ρ of positive and negative polarity conductors + and ρ - ;

[0149] Using the L2 norm formula, calculate the standardized vector (a1, a2, a3, a4, a5, a6, a7) corresponding to the line parameter set. T The L2 distance between the normalized computational parameter vectors corresponding to the DC transmission line:

[0150] Determine the line parameter group that has the smallest L2 distance to the standardized calculated parameter vector;

[0151] From the pre-constructed set of line parameters, obtain the initial values ​​of surface charge density of positive and negative polarity conductors corresponding to the line parameter group with the smallest L2 distance to the standardized calculation parameter vector, and generate the leading values ​​of surface charge density corresponding to the DC transmission line.

[0152] Specifically, using the bubble sort method, the minimum value of the L2 distance ||X0|| between the line parameter group recorded in the line parameter set and the standardized calculation parameter vector is selected, and the initial values ​​ρ of the positive and negative polarity surface charge density corresponding to this line parameter group are recorded. 0+ and ρ 0- .

[0153] The generation of the surface charge density precursor value corresponding to the DC transmission line includes:

[0154] If ||X0||≤1, then the surface charge density leader value corresponding to the DC transmission line is set to ρ. 0+ and ρ 0- ;

[0155] If ||X0||>1, then the leading values ​​of the positive and negative polarity surface charge density corresponding to the DC transmission line are calculated according to the following empirical formula.

[0156] Where ε0 is the vacuum permittivity, U0 is the corona initiation voltage of the conductor, E0 is the corona initiation field strength, and E g U is the electric field strength directly below the conductor, U is the conductor operating voltage, which is the voltage level corresponding to the aforementioned DC transmission line, r is the aforementioned sub-conductor radius, and h is the aforementioned conductor height.

[0157] Specifically, the halo initiation field strength E0 can be calculated using the Peek formula, and the positive halo initiation field strength... Take on the strong dizziness Where δ=pT0 / (p0T) is the relative density of air, which is related to air pressure and temperature, where the current air pressure is p, the standard air pressure is p0, the current temperature is T, and the standard temperature is T0; m is the aforementioned roughness coefficient, and r is the aforementioned sub-conductor radius.

[0158] The minimum L2 distance ||X0|| is compared with the L2 distance limit 1, and a leading value of surface charge density corresponding to the DC transmission line is generated.

[0159] Thus, when the minimum value is not greater than the preset L2 distance limit, the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation is determined as the leading value of the conductor surface charge density corresponding to the DC transmission line.

[0160] When the minimum value is greater than the preset L2 distance limit, the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation is corrected according to the empirical formula, and the corrected initial value of the conductor surface charge density is determined as the leading value of the conductor surface charge density corresponding to the DC transmission line.

[0161] The L2 norm distance limit is set to 1 based on the following considerations: (500kV, 4, 450mm, 15mm, 15m, 14m, 0.47) T The standardized vector is (5, 0.4, 0.9, 1, 1.5, 0.7, 0.4). T ;(660kV,4,450mm,15mm,15m,14m,0.47) T The standardized vector is (6.6, 0.4, 0.9, 1, 1.5, 0.7, 0.4). T For example, the L2 distance between these two parameter sets is 1.6. The most significant voltage levels affecting these two parameter sets differ, typically resulting in a large difference in the initial charge density values. To indicate the difference between them, a distance limit of 1 is chosen.

[0162] Step 4: Establish an overhead transmission line model. Based on the upstream finite element method, using the surface charge density precursor value and the calculation parameter set corresponding to the DC transmission line, iteratively calculate the ground DC composite electric field and conductor surface charge density until the charge density in the entire field is stable and satisfies the Kaptzov assumption. Record the positive and negative polarity conductor surface charge densities at the end of the iteration and determine them as the initial values ​​of the positive and negative polarity conductor surface charge densities corresponding to the DC transmission line.

[0163] Specifically, the initial values ​​of the surface charge density of the positive and negative polarity conductors are calculated, including:

[0164] Step 41: Establish an overhead transmission line model, which includes Poisson's equation and current continuity equation;

[0165] Step 42: Based on the generated leading values ​​of the positive and negative polarity surface charge density corresponding to the DC transmission line, calculate the Poisson equation and the current continuity equation using the upstream finite element method until the charge density in the entire field stabilizes, and obtain the maximum value E of the electric field intensity on the surface of the positive and negative polarity conductors. max+ and E max- and the surface charge density of positive and negative polarities.

[0166] Step 43: Calculate the maximum value E of the electric field intensity on the surface of the positive and negative polarity conductors. max+ and E max- The positive and negative halo field strength E respectively 0+ and E 0- By comparing the results, the relative error of the field strength is generated;

[0167] If the relative error of the field strength is less than the specified limit, no correction is required; the positive and negative polarity surface charge densities obtained when the charge density of the entire field is stable are determined as the initial values ​​of the positive and negative polarity conductor surface charge densities corresponding to the DC transmission line.

[0168] If the relative error of the electric field strength is not less than the specified limit, the positive and negative polarity surface charge densities are corrected according to the following formula:

[0169]

[0170] The value of μ is set to 2.1, the specified limit value of the relative error of the field strength is 0.005, and n is the number of iteration rounds.

[0171] Return to step 42 and proceed to the next iteration. Use the upstream finite element method to update the charge density and the electric field strength on the surface of the conductor until the relative error of the electric field strength on the surface of the positive and negative polarity conductors, determined when the charge density in the entire field is stable, meets the specified limit, that is, it is less than the specified limit.

[0172] Step 44: When the relative error of the field strength meets the specified limit, the positive and negative polarity surface charge density determined when the charge density of the entire field is stable is determined as the initial value of the positive and negative polarity conductor surface charge density corresponding to the DC transmission line.

[0173] Thus, the distribution of the ground electric field intensity, that is, the ground DC composite electric field and the amplitude of the surface charge density of the positive and negative polarity conductors, are recorded. In other words, the surface charge density of the positive and negative polarity obtained when the charge density of the entire field is stable is determined as the initial value of the surface charge density of the positive and negative polarity conductors corresponding to the DC transmission line.

[0174] In the process of iteratively calculating the ground DC composite electric field and the surface charge density of the conductor, using the leading value of the surface charge density as the initial value of the surface charge density of the positive and negative polarity conductors when entering the iteration is beneficial to speed up convergence and improve calculation efficiency.

[0175] Step 5: Add the line parameter sets corresponding to the DC transmission line, the standardized calculation parameter vector, and the initial values ​​of the surface charge density of the positive and negative polarity conductors corresponding to the DC transmission line to the line parameter set.

[0176] In summary, the method for determining the initial value of conductor surface charge density based on the second norm and the method for rapid calculation of DC composite electric field in the embodiments of this application can quickly obtain the initial value of conductor surface charge density that is conducive to approaching the final calculation result by traversing the line parameter set for DC transmission lines.

[0177] The above example illustrates the method for determining the initial value of conductor surface charge density based on the second norm in this application, using the determination of the initial value of charge density for calculating the DC composite electric field of a single DC transmission line as an example. As the number of engineering examples increases, the number of line parameter groups within the line parameter set continues to rise. The number of standardized calculation parameter vectors and initial values ​​of positive and negative polarity conductor surface charge density recorded in the line parameter set for each DC transmission line is also greater. This leads to more accurate initial value selection and further improves the calculation efficiency of the composite electric field.

[0178] In some embodiments, the method for determining the initial value of the surface charge density of the conductor based on the second norm and the method for calculating the DC composite electric field are used for, for example... Figure 3 The engineering example shown is an ±800kV DC transmission line using 6-split conductors. The sub-conductor model is JL1 / G1A-1250 / 70, with a diameter of 47.4mm or a radius of 23.7mm, a split spacing of 500mm, horizontal arrangement, a conductor height of 26m, and an electrode spacing of 20m.

[0179] Specifically, the values ​​of the above parameters, such as voltage level, number of conductor splits, split spacing, sub-conductor radius, conductor height, conductor pole spacing, and conductor roughness coefficient, are read and a calculation parameter vector is constructed: (800kV, 6, 500mm, 23.7mm, 26m, 20m, 0.47). T ;

[0180] (100kV, 10, 500mm, 15mm, 10m, 20m, 1) T The calculated parameter vector is standardized using the reference vector to obtain the standardized calculated parameter vector (8, 0.6, 1, 1.58, 2.6, 1, 0.47). T .

[0181] Specifically, when calculating the initial value of the surface charge density of the conductor, the standardized calculation parameter vector (a1,a2,a3,a4,a5,a6,a7) recorded in the line parameter set is read. T and the initial values ​​ρ of the surface charge density of the corresponding positive and negative polarity conductors. + and ρ - The standardized parameter vector (8, 0.6, 1, 1.58, 2.6, 1, 0.47) was calculated using the L2 norm formula. T Compared with the standardized vectors (a1, a2, a3, a4, a5, a6, a7) recorded in the line parameter set. T 2-norm distance:

[0182] The standardized calculation parameter vector is (8, 0.6, 1, 1.58, 2.6, 1, 0.47). T This corresponds to the 100 standardized vectors (a1, a2, a3, a4, a5, a6, a7) recorded in the line parameter set. T The calculated results of the L2 norm distance between them are shown as follows Figure 4 Thus, using the bubble sort method, the minimum L2 distance is determined to be 0.112, corresponding to the index 12 of the computational parameter vector. Referring to the previous explanation, the relationship between the minimum L2 distance and the L2 distance limit of 1 is determined. Since 0.112 < 1, the initial values ​​of the positive and negative charge densities corresponding to the standardized vector with index 12 are 8.9102 nC / m². 3 and -9.1094nC / m 3 The corresponding line parameter set is (800kV, 6, 450mm, 23.7mm, 26.5m, 20m, 0.47). T .

[0183] The line parameter group is (800kV, 6, 450mm, 23.7mm, 26.5m, 20m, 0.47).T The corresponding initial values ​​for positive and negative polarity charge densities are 8.9102 nC / m². 3 and -9.1094nC / m 3 The constructed calculation parameter vector is (800kV, 6, 500mm, 23.7mm, 26m, 20m, 0.47). T The corresponding surface charge density leader value.

[0184] Specifically, the following calculations utilize the parameter set (800kV, 6, 500mm, 23.7mm, 26m, 20m, 0.47). T The corresponding positive and negative polarity conductor surface charge density precursor values ​​are used to calculate the combined electric field and the positive and negative polarity conductor surface charge density of the ±800kV DC transmission line.

[0185] Specifically, an overhead transmission line model is established, and the surface charge density of the conductor is iteratively calculated using the upstream finite element method until the charge density across the entire field stabilizes and satisfies the Kaptzov assumption, i.e., the electric field strength on the conductor surface is equal to the corona induction field strength. At this point, the surface charge density of the positive and negative polarity conductors is 8.9102 nC / m. 3 and -9.3427nC / m 3 The calculation parameter set was determined to be (800kV, 6, 500mm, 23.7mm, 26m, 20m, 0.47). T The corresponding initial value of surface charge density.

[0186] Figure 5 The computation time and number of iterations consumed by the calculation method of this application embodiment (as shown in A) are respectively compared with the computation time and number of iterations consumed by the traditional method for calculating the composite electric field of a DC transmission line (as shown in B). From Figure 5 As can be seen from the above, the calculation method of this application embodiment calculates the result after 8 iterations and 123 seconds; while the traditional calculation method calculates the result after 41 iterations and 864 seconds.

[0187] Furthermore, the calculation parameter set (800kV, 6, 500mm, 23.7mm, 26m, 20m, 0.47) was used. T The standardized parameter vector is calculated as (8, 0.6, 1, 1.58, 2.6, 1, 0.47). T The surface charge density of the positive and negative polarity conductors is 8.9102 nC / m. 3 and -9.3427nC / m 3 This is added to the line parameter set as a line parameter group. Thus, the standardized calculation parameter vector is (8,0.6,1,1.58,2.6,1,0.47). T The surface charge density of the positive and negative polarity conductors is 8.9102 nC / m.3 and -9.3427nC / m 3 It can be used to calculate the L2 norm distance or as a leading value of the surface charge density of positive and negative polarity conductors, which can then be used to calculate the composite electric field of other DC transmission lines or to calculate the initial value of the surface charge density of positive and negative polarity conductors.

[0188] Thus, in this embodiment, the L2 norm distance is used to determine which set of line parameters in the line parameter set is closest to the set of line parameters to be calculated for the composite electric field. This yields the initial value of the conductor surface charge density required for the iterative calculation of the composite electric field. Subsequently, based on this initial value of the conductor surface charge density, the composite electric field is calculated quickly and efficiently using the iterative method based on the upstream finite element method. This method has fast convergence and reduces the computation time consumed in calculating the composite electric field. Furthermore, the final result is added to the line parameter set, gradually enriching the amount of data within the line parameter set.

[0189] This method based on the second norm is beneficial for quickly obtaining an initial value of the surface charge density of the conductor that is closer to the final iterative result, providing technical support for the rapid iterative convergence of the synthesized electric field.

[0190] This application also provides a terminal 8 to execute the above-described method for determining the initial value of the surface charge density of a conductor based on the second norm. Please refer to... Figure 6 The diagram illustrates a terminal provided by some embodiments of this application. For example... Figure 6 As shown, terminal 8 includes: processor 800, memory 801, bus 802 and communication interface 803. The processor 800, communication interface 803 and memory 801 are connected through bus 802. The memory 801 stores a computer program that can run on the processor 800. When the processor 800 runs the computer program, it executes the method for determining the initial value of surface charge density of a conductor based on the second norm provided in any of the foregoing embodiments of this application.

[0191] The memory 801 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this device network element and at least one other network element is achieved through at least one communication interface 803 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc.

[0192] Bus 802 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory 801 is used to store programs. After receiving an execution instruction, the processor 800 executes the program. The method for determining the initial value of the surface charge density of a wire based on the second norm disclosed in any of the foregoing embodiments of the present invention can be applied to the processor 800, or implemented by the processor 800.

[0193] The processor 800 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of the processor 800 or by instructions in software form. The processor 800 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules may reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 801. Processor 800 reads the information in memory 801 and, in conjunction with its hardware, completes the steps of the above method.

[0194] The terminal provided in this embodiment of the invention and the method for determining the initial value of the surface charge density of a conductor based on the second norm in this embodiment of the invention are based on the same inventive concept and have the same beneficial effects as the methods used, operated or implemented.

[0195] This application also provides a computer-readable storage medium corresponding to the method for determining the initial value of the surface charge density of a conductor based on the second norm provided in the foregoing embodiments. The computer-readable storage medium is an optical disc, on which a computer program (i.e., a program product) is stored. When the computer program is run by a processor, it executes the method for determining the initial value of the surface charge density of a conductor based on the second norm provided in any of the foregoing embodiments.

[0196] It should be noted that examples of the computer-readable storage medium may also include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other optical and magnetic storage media, which will not be elaborated here.

[0197] The computer-readable storage medium provided in the above embodiments of this application and the method for determining the initial value of surface charge density of a conductor based on the second norm of the present invention are based on the same inventive concept and have the same beneficial effects as the methods used, run or implemented by the applications stored therein.

[0198] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for determining the initial value of the surface charge density of a wire based on the two-norm, characterized in that, include: Generate a standardized calculation parameter vector corresponding to the DC transmission line; Determining the degree of deviation between each group of line parameters recorded in the pre-constructed line parameter set and the standardized calculated parameter vector includes: The standardized vectors corresponding to each line parameter group recorded in the pre-constructed line parameter set and the L2 norm of the standardized calculated parameter vector indicate the degree of deviation between each line parameter group and the standardized calculated parameter vector. Based on the initial value of conductor surface charge density corresponding to the line parameter group with the smallest deviation, a leading value of conductor surface charge density corresponding to the DC transmission line is generated, including: Determine the minimum value between the standardized vector corresponding to each group of line parameters recorded in the pre-constructed line parameter set and the L2 norm of the standardized calculated parameter vector; The line parameter group corresponding to the minimum value is determined as the line parameter group with the smallest deviation. Compare the relative magnitude of the minimum value with the preset L2 distance limit, and generate a lead value of the conductor surface charge density corresponding to the DC transmission line based on the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation. When the minimum value is not greater than the preset L2 distance limit, the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation is determined as the leading value of the conductor surface charge density corresponding to the DC transmission line. When the minimum value is greater than the preset L2 distance limit, the initial value of the conductor surface charge density corresponding to the line parameter group with the smallest deviation is corrected according to the empirical formula, and the corrected initial value of the conductor surface charge density is determined as the leading value of the conductor surface charge density corresponding to the DC transmission line. The initial values ​​of the surface charge density of the positive and negative polarity conductors corresponding to the line parameter set with the smallest deviation are corrected according to the following empirical formula: ; in, ε 0 is the vacuum permittivity. U 0 represents the corona initiation voltage of the conductor. E 0 indicates the intensity of the dizziness field. E g The electric field strength is directly below the conductor. U The operating voltage of the conductor. r The radius of the sub-conductor. h The height of the conductor; Among them, the field strength of the positive dizziness E 0+ Determined according to the following formula: ； Take on the strong dizziness E 0- Determined according to the following formula: ； The relative density of air is determined by the following formula: ; The current air pressure is p Standard air pressure is p 0; Current temperature is T， Standard temperature is T 0; m The roughness coefficient of the conductor; Using the generated leading value of the conductor surface charge density, the conductor surface charge density and DC composite electric field corresponding to the DC transmission line are calculated iteratively; when the charge density in the entire field is stable and satisfies the Kaptzov assumption, the iteration is terminated, and the positive and negative polarity conductor surface charge densities determined in the current iteration are determined as the initial values ​​of the positive and negative polarity conductor surface charge densities corresponding to the DC transmission line.

2. The method for determining the initial value of surface charge density of a conductor based on the second norm as described in claim 1, characterized in that, The generated standardized calculation parameter vector corresponding to the DC transmission line includes: Obtain the calculation parameter set corresponding to the DC transmission line; Arrange the parameters in the calculation parameter group into a calculation parameter vector according to a preset order; The computational parameter vector is standardized to obtain the standardized computational parameter vector.

3. The method for determining the initial value of surface charge density of a conductor based on the second norm as described in claim 2, characterized in that, The parameters in the calculation parameter group corresponding to the DC transmission line include: Voltage level, number of conductor splits, split spacing, sub-conductor radius, conductor height, conductor pole spacing, conductor roughness coefficient; The standardization process for the computational parameter vector, resulting in the standardized computational parameter vector, includes: A reference vector is constructed with a voltage level of 100kV, a conductor split number of 10, a split spacing of 500mm, a sub-conductor radius of 15mm, a conductor height of 10m, a conductor pole spacing of 20m, and a conductor roughness coefficient of 1. The quotient obtained by dividing each element in the computational parameter vector by each element in the constructed baseline vector is used as each element in the standardized computational parameter vector.

4. The method for determining the initial value of surface charge density of a conductor based on the second norm as described in claim 1, characterized in that, include: An overhead transmission line model is established, which includes the Poisson equation and the current continuity equation. Based on the generated surface charge density precursor value corresponding to the DC transmission line, the Poisson equation and the current continuity equation are calculated using the upstream finite element method until the charge density in the entire field stabilizes, thus obtaining the maximum value of the electric field strength on the surface of the positive polarity conductor. E max+ and the maximum value of the electric field strength on the surface of the negative polarity conductor E max- and the surface charge density of positive and negative polarities; The maximum values ​​of the electric field strength on the surface of the positive polarity conductor and the maximum values ​​of the electric field strength on the surface of the negative polarity conductor are respectively compared with the positive polarity field strength. E 0+ and the strong dizziness E 0- Compare and generate the relative error of the field strength; If the relative error of the field strength is less than the specified limit of the field strength, the positive and negative polarity surface charge density determined when the charge density of the entire field is stable is determined as the initial value of the positive and negative polarity conductor surface charge density corresponding to the DC transmission line. If the relative error of the electric field strength is not less than the specified limit of the electric field strength, the positive and negative polarity surface charge densities determined when the charge density of the entire field is stable shall be corrected according to the following formula: ； in, μ The value is set to 2.1, and the specified limit value for field strength is 0.005; n This represents the number of iteration rounds. In the next iteration, the charge density and the electric field strength on the surface of the conductor are updated using the upstream finite element method until the relative error of the electric field strength on the surface of the conductor, which is determined when the charge density in the whole field is stable, meets the specified limit of the electric field strength. When the relative error of the electric field strength meets the specified limit of the electric field strength, the positive and negative polarity surface charge density determined when the charge density of the entire field is stable is determined as the initial value of the positive and negative polarity conductor surface charge density corresponding to the DC transmission line.

5. A terminal, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the method of any one of claims 1 to 4.

6. A computer storage medium, characterized in that, The device stores computer-executable instructions for performing the method of any one of claims 1 to 4.

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