A direct current synthetic electric field calculation method and device, a terminal and a storage medium

Abstract

The application discloses a direct current synthetic electric field calculation method, and discloses an apparatus, a terminal and a storage medium with the direct current synthetic electric field calculation method. The direct current synthetic electric field calculation method can be used to calculate a synthetic electric field above a building near a direct current transmission line under the condition of a wind speed, and provides a calculation method of the synthetic electric field above the building and a calculation method of a building flow field, and solves the vacancy that the existing method rarely considers the situation above the building.

Description

Technical Field

[0001] This invention relates to the field of high-voltage electric field calculation, and in particular to a method for calculating DC composite electric fields. Background Technology

[0002] Ultra-high voltage (UHV) refers to power transmission technologies with voltage levels of 1000 kV and above for AC and ±800 kV and above for DC. These technologies offer advantages such as large transmission capacity, long distances, high efficiency, and low losses. However, UHV AC and DC transmission projects also generate electromagnetic environment problems around the lines. One of the key factors affecting the electromagnetic environment around UHV DC transmission lines is the DC composite electric field. Effectively predicting the DC composite electric field is of significant practical importance for controlling electromagnetic environment problems around DC transmission lines and ensuring a friendly electromagnetic environment for residential areas along the transmission and transformation projects.

[0003] Due to limited transmission corridors, ultra-high-voltage direct current (UHVDC) transmission lines inevitably pass near densely populated areas. Residential platforms and balconies are often considered electromagnetically sensitive points and key indicators in environmental assessments. Furthermore, the DC composite electric field is closely related to environmental factors such as temperature, humidity, airborne particulate matter, and wind speed. Wind speed, in particular, directly affects the distribution of spatial charge, thus altering the DC composite electric field distribution. Past observations show that wind speeds above buildings are significantly higher than at ground level, a result of wind flowing around buildings. However, existing algorithms generally assume wind speeds are uniform everywhere, which clearly does not conform to the wind speed distribution patterns and physical properties when buildings are present. This leads to deviations in the calculated composite electric field, necessitating a method for calculating the DC composite electric field that considers wind flow around buildings. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for calculating DC composite electric fields, which can reduce the errors caused by neglecting the influence of wind speed in traditional methods.

[0005] The present invention also proposes an apparatus, a terminal and a storage medium having the above-mentioned method for calculating DC composite electric field.

[0006] The method for calculating the DC composite electric field according to a first aspect of the present invention includes the following steps: Establish a standard k-ɛ model for wind field around a building to calculate the turbulent flow conditions around the building; A nominal electric field calculation model for a high-voltage direct current line is established. By comparing the surface electric field strength of the conductor with the corona induction field strength of the positive and negative conductors, the corona induction status of the conductor is determined. Based on the corona formation and turbulence conditions of the conductors, the initial values ​​of the surface charge density of the positive and negative conductors are estimated and corrected. The Poisson equation and the current continuity equation are solved by the upstream finite element method considering wind speed flow to determine the electric field distribution and charge density distribution until the charge density and field strength distribution are stable. Based on the current charge density on the surface of the conductor, calculate the overall charge density and the distribution of the combined electric field intensity.

[0007] The DC composite electric field calculation method according to embodiments of the present invention has at least the following beneficial effects: the method takes into account the influence of wind speed on the electric field in densely built-up areas, reducing the error of traditional electric field calculation methods.

[0008] According to some embodiments of the present invention, the step of establishing a computational model of the wind field around a building and calculating the turbulence problem of the wind around the building using the standard k-ɛ model includes: The site and buildings are modeled and partitioned to calculate the inlet wind speed at different heights; Based on Boussinesq's eddy viscosity assumption, the standard k-ɛ model was used and solved using the finite element method to obtain the turbulence conditions around the building.

[0009] According to some embodiments of the present invention, the step of establishing a nominal electric field calculation model for a high-voltage direct current line and determining the corona initiation status of the conductor by comparing the surface electric field strength of the conductor with the corona initiation field strength of the positive and negative conductors includes: The simulated charge method combined with the image method is used to set simulated charges inside the conductor and at symmetrical positions with the ground as the baseline. Matching points are selected on the surface of the conductor to calculate the simulated charge values ​​in the positive and negative conductors. The electric field components in the x and y directions and the nominal electric field amplitude on the surface of the conductors are calculated based on the simulated charge values ​​in the positive and negative conductors. The halo field strength can be calculated using the Peek formula. By comparing the magnitude of the corona initiation field strength with the nominal electric field amplitude on the surface, the corona initiation status of the conductor can be determined.

[0010] According to some embodiments of the present invention, the step of estimating and correcting the initial values ​​of the surface charge density of the positive and negative conductors, solving the Poisson equation and the current continuity equation using the upstream finite element method considering wind speed flow, until the charge density and field strength distribution are stable, includes: Predict the initial value of the surface charge density of the conductor; The electric field distribution is solved by discretizing the Poisson equation using the finite element method. Using the upper flow element method and taking into account the wind speed around the building, the charge density distribution is solved; Determine if the charge density is stable. If it is not stable, repeat the solution for the electric field distribution and charge density distribution until it is stable.

[0011] According to some embodiments of the present invention, after the step of determining whether the charge density is stable, and if not, repeating the solution of the electric field distribution and charge density distribution until stable, the method further includes: Calculate the maximum electric field strength on the conductor surface at this time and compare it with the positive and negative corona field strength. If the error is greater than the specified limit, then correct it.

[0012] A DC composite electric field calculation apparatus according to a second aspect embodiment of the present invention includes: The turbulence model calculation module can establish a calculation model of the wind field around a building and calculate the turbulence problem of wind around a building using the standard k-ɛ model; The corona initiation status judgment module can establish a nominal electric field calculation model for high voltage DC lines and judge the corona initiation status of the conductor by comparing the surface electric field strength of the conductor with the corona initiation field strength of the positive and negative conductors. The iterative calculation module can predict and correct the initial values ​​of the surface charge density of positive and negative conductors, and solve the Poisson equation and the current continuity equation by considering the upstream finite element method of wind speed flow until the charge density and field strength distribution are stable. The distributed calculation module can calculate the charge density and the distribution of the combined electric field intensity across the entire field based on the current charge density on the surface of the conductor.

[0013] Furthermore, the turbulence model calculation module includes: The analysis element can model and partition a field and a building, and calculate the inlet wind speed at different heights; The finite element analysis element, based on Boussinesq's eddy viscosity assumption, uses the standard k-ɛ model and is solved using the finite element method to obtain the turbulent conditions around the building.

[0014] Furthermore, the dizziness state determination module includes: The charge calculation element can use the simulated charge method combined with the mirror method to set simulated charges in the conductor and at symmetrical positions with the ground as the baseline, select matching points on the surface of the conductor, and calculate the simulated charge values ​​in the positive and negative conductors. The surface characterization electric field amplitude calculation element can solve the electric field components in the x and y directions of the conductor surface and the nominal electric field amplitude of the conductor surface based on the simulated charge values ​​in the positive and negative conductors. The element for calculating the halo field strength can be used to solve for the halo field strength using the Peek formula; The corona initiation determination element can compare the magnitude of the corona initiation field strength and the nominal electric field amplitude on the surface to determine the corona initiation status of the conductor.

[0015] Furthermore, the iterative calculation module includes: The density initial value prediction element can predict the initial value of the surface charge density of the conductor; The electric field solving element uses the finite element method to discretize the Poisson equation and solve for the electric field distribution; The density distribution solution element is obtained by using the upper flow element method, taking into account the wind speed around the building, and solving for the charge density distribution. Determine if the charge density is stable. If it is not stable, repeat the solution for the electric field distribution and charge density distribution until it is stable.

[0016] According to a third aspect of this application, a terminal is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the aforementioned DC composite electric field calculation method. According to a fourth aspect of this application, a computer-readable storage medium is provided that stores computer-executable instructions for performing the above-described DC composite electric field calculation method.

[0017] This invention adds the influence of wind speed at different heights to the traditional k-ɛ model of wind field to calculate turbulence and determine the corona formation of conductors. Then, it solves for electric field distribution and charge density based on turbulence and corona formation. By adding the influence of wind speed on the calculation results to the traditional model, it can consider the influence of non-uniform wind speed on the electric field when calculating the electric field distribution, and obtain more accurate calculation results.

[0018] 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

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram illustrating the steps of a DC composite electric field calculation method according to an embodiment of the present invention; Figure 2 for Figure 1 A detailed schematic diagram of step S100 of the DC composite electric field calculation method is shown; Figure 3 A schematic diagram of wind speed field calculation results in the DC composite electric field calculation method provided in the embodiments of this application; Figure 4 for Figure 1 A detailed schematic diagram of step S200 of the DC composite electric field calculation method is shown; Figure 5 for Figure 1 A detailed schematic diagram of step S300 of the DC composite electric field calculation method is shown; Figure 6This is an electric field intensity distribution diagram obtained from an embodiment of this application; Figure 7 This is a charge density distribution diagram of the entire field obtained from an embodiment of this application; Figure 8 This is a schematic diagram illustrating the steps of a DC synthetic electric field calculation device according to an embodiment of the present invention. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0022] When DC high-voltage transmission lines pass through densely populated areas, the impact of buildings on the electromagnetic environment is often difficult to ignore. In addition to distortion, buildings also affect wind speed, meaning that the wind speed above buildings is significantly higher than at ground level. This is because the wind flows around the buildings, which directly affects the distribution of space charge and thus changes the distribution of the DC composite electric field.

[0023] Example 1 To address the shortcomings of existing algorithms that do not consider wind-driven structures, a method for calculating the DC composite electric field of structures that does consider wind-driven structures is provided, referring to... Figure 1 This method can be divided into the following steps: Step S100: Establish a standard k-ɛ model of the wind field around the building to calculate the turbulence conditions of the wind around the building.

[0024] Step S200: Establish a nominal electric field calculation model for a high-voltage DC line, and determine the corona formation status of the conductor by comparing the surface electric field strength of the conductor with the corona formation field strength of the positive and negative conductors.

[0025] Step S300: Based on the corona formation and turbulence of the conductors, estimate and correct the initial values ​​of the surface charge density of the positive and negative conductors. Consider the upward finite element method of wind speed flow to solve the Poisson equation and the current continuity equation to determine the electric field distribution and charge density distribution until the charge density and field strength distribution are stable.

[0026] Step S400: Calculate the total charge density and the distribution of the combined electric field intensity based on the current charge density on the surface of the conductor.

[0027] To explain the steps of this method and the formulas used in the calculation process in more detail, the above embodiments will now be described in more detail: Step S100: Establish a standard k-ɛ model of the wind field around a building to calculate the turbulence problem of wind flowing around the building. (Refer to...) Figure 2 ,include: Step S101: Model and partition the field and buildings, and calculate the inlet wind speed at different heights.

[0028] The Reynolds-averaged equations are typically used to consider wind field problems, mainly including the continuity equation and the momentum equation: (1) (2) Step S102: Based on Boussinesq's eddy viscosity assumption, the standard k-ɛ model is used to make the Reynolds-averaged equations discretized and the equation set closed, and then solved using the finite element method.

[0029] The Reynolds stress is typically determined using turbulent models, employing Boussinesq's eddy viscosity assumption. (3) Where k is the turbulent kinetic energy, defined as ;v t It is the turbulent viscosity coefficient. α is the viscous dissipation of turbulent flow, where k and α can be determined by the following two equations: (4) (5) Where P is the turbulent energy generation rate, defined as The empirical coefficients in formulas (4) and (5) are taken as follows: =0.09, =1.0, =1.3, =1.44, =1.92.

[0030] Given a 200m × 100m two-dimensional computational field, the wind speed w input at the left end satisfies: (6) In the formula, w0 = 5 m / s, α = 0.16. The right-end exit boundary adopts a free boundary; the ground and buildings are "fixed walls": no-slip boundary conditions are adopted; the calculated wind speed field results are as follows. Figure 3 As shown.

[0031] Step S200: Establish a nominal electric field calculation model for the high-voltage DC line. By comparing the surface electric field strength of the conductor with the corona induction field strength of the positive and negative conductors, determine the corona induction status of the conductor. (Refer to...) Figure 4 ,include: Step S201: Using the simulated charge method combined with the mirror method, simulated charges are set in the conductor and at symmetrical positions with the ground as the baseline. Matching points are selected on the surface of the conductor, and the simulated charge values ​​in the positive and negative conductors are calculated.

[0032] The method of simulated charge combined with the method of images is used to set simulated charges inside the conductor and at symmetrical positions with the ground as the baseline, and matching points are selected on the surface of the conductor. Solve equation (7) to calculate the simulated charge values ​​Q1 and Q2 in the positive and negative conductors; (7) Step S202: Based on the simulated charge values ​​in the positive and negative conductors, calculate the electric field components in the x and y directions on the conductor surface and the nominal electric field amplitude on the conductor surface.

[0033] Based on the simulated charge values ​​Q1 and Q2 in the positive and negative conductors, solve for the electric field components in the x and y directions on the conductor surface. , Then by Solve for the nominal electric field amplitude on the surface of the conductor. E 0max± ; Step S203: Use the Peek formula to solve for the halo field strength.

[0034] Use peek formula , Determine the intensity of the halo field.

[0035] in, δ The relative density of air is determined by... Find it; r Let be the sub-radius of the split conductor.

[0036] Step S300: Based on the corona formation and turbulence of the conductors, estimate and correct the initial values ​​of the surface charge density of the positive and negative conductors. Consider the upward finite element method of wind speed flow to solve the Poisson equation and the current continuity equation to determine the electric field distribution and charge density distribution until the charge density and field strength distribution are stable.

[0037] The main model equations for the ion flow field in a bipolar DC transmission line are as follows: (8) (9) (10) (11) (12) (13) In the formula: The potential value; E The electric field intensity vector; w This is the wind speed vector; ρ + , ρ - These are the positive and negative space charge densities, respectively. k + , k - These represent the mobility of positive and negative ions, respectively; R is the recombination coefficient of positive and negative ions. J + , J - These are the positive and negative ion current density vectors, respectively. e It is the basic electron charge. , E , ρ + , ρ - , J + , J - unknown variables w , k + , k - , R , e These are known parameters.

[0038] The specific calculation process for step S300 can be found in [reference]. Figure 5 ,include: Step S301: Estimate the initial value of the surface charge density of the conductor.

[0039] Adopted To estimate the initial value of the surface charge density of the conductor; in, ε 0 is the vacuum dielectric constant. U c0 The corona initiation voltage of the conductor. E g This represents the maximum nominal ground field strength. U The operating voltage of the conductor. r The radius of the sub-conductor. h The height of the conductor above the ground. E c0 The corona field strength of the sub-conductor.

[0040] Step S302: Solve the Poisson equation using the finite element method to obtain the electric field distribution.

[0041] The finite element method is based on existing principles and will not be elaborated upon here.

[0042] Step S303: Solve for the charge density distribution.

[0043] Using the upper flow element method, based on the ion movement formula that takes wind speed into account... Discrete current continuity equation and Solve for the charge density distribution; Step S304: Determine whether the charge density is stable. If it is not stable, repeat the solution for the electric field distribution and charge density distribution until it is stable.

[0044] Judgment basis Determine if the charge density is stable. If the equation does not hold, repeat steps S302 and S303 until it does; if the equation holds, the calculation ends. In this embodiment, the maximum relative error between two charge density measurements is... δ 1≤0.05%.

[0045] Preferably, to ensure a certain level of calculation accuracy, step S300 further includes: Step S305: Calculate the maximum electric field strength on the surface of the conductor at this time, and compare it with the positive and negative corona electric field strength. If the error is greater than the specified limit, then correct it.

[0046] Comparing the error between the surface electric field strength and the corona induction electric field strength, in this embodiment, the error is selected to be less than or equal to 0.5%. When the error of the conductor surface electric field strength is not met, the surface charge density is corrected according to equation (14): (14) in ρ s ( n )and ρ s ( n- 1) respectively the first n Second and third n -1st surface charge density value, E m This represents the maximum amplitude of the electric field intensity on the surface of the conductor. E onset To induce dizziness, μ >0 is the correction factor.

[0047] Step S400: Calculate the total charge density and the distribution of the combined electric field intensity based on the current charge density on the surface of the conductor.

[0048] By using the finite element method to solve the Poisson equation, the electric field intensity distribution and charge density distribution of the entire field can be obtained through interpolation.

[0049] Ground electric field intensity distribution is shown in Figure 6 The charge density distribution across the entire field is shown in [reference needed]. Figure 7 .

[0050] Another embodiment of this application provides a DC composite electric field calculation device, referring to... Figure 8 The device 20 includes: The turbulence model calculation module 201 can establish a standard k-ɛ model of the wind field around a building to calculate the turbulence problem of wind around a building; The corona initiation state judgment module 202 can establish a nominal electric field calculation model of a high-voltage DC line and judge the corona initiation status of the conductor by comparing the surface electric field strength of the conductor with the corona initiation field strength of the positive and negative conductors. The iterative calculation module 203 can estimate and correct the initial values ​​of the surface charge density of the positive and negative conductors based on the corona formation and turbulence conditions of the conductors. It can solve the Poisson equation and the current continuity equation by considering the finite element method of wind speed flow to determine the electric field distribution and charge density distribution until the charge density and field strength distribution are stable. The distribution calculation module 204 can calculate the distribution of charge density and combined electric field intensity across the entire field based on the current charge density on the surface of the conductor.

[0051] Furthermore, the turbulence model calculation module includes: The analysis element can model and partition a field and a building, and calculate the inlet wind speed at different heights; The finite element analysis element, based on Boussinesq's eddy viscosity assumption, uses the standard k-ɛ model and is solved using the finite element method to obtain the turbulent conditions around the building.

[0052] Furthermore, the dizziness state determination module includes: The charge calculation element can use the simulated charge method combined with the mirror method to set simulated charges in the conductor and at symmetrical positions with the ground as the baseline, select matching points on the surface of the conductor, and calculate the simulated charge values ​​in the positive and negative conductors. The surface characterization electric field amplitude calculation element can solve the electric field components in the x and y directions of the conductor surface and the nominal electric field amplitude of the conductor surface based on the simulated charge values ​​in the positive and negative conductors. The element for calculating the halo field strength can be used to solve for the halo field strength using the Peek formula; The corona initiation determination element can compare the magnitude of the corona initiation field strength and the nominal electric field amplitude on the surface to determine the corona initiation status of the conductor.

[0053] Furthermore, the iterative calculation module includes: The density initial value prediction element can predict the initial value of the surface charge density of the conductor; The electric field solution element uses the finite element method to discretize the Poisson equation and solve for the electric field distribution. The density distribution solution element is obtained by using the upper flow element method, taking into account the wind speed around the building, and solving for the charge density distribution. Determine if the charge density is stable. If it is not stable, repeat the solution for the electric field distribution and charge density distribution until it is stable.

[0054] Another embodiment of this application provides a terminal, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described DC composite electric field calculation method.

[0055] Specifically, the processor can be a CPU, a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements computational functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0056] Specifically, the processor connects to the memory via a bus, which may include a path for transmitting information. The bus can be a PCI bus or an EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc.

[0057] The memory may be ROM or other types of static storage devices that can store static information and instructions, RAM or other types of dynamic storage devices that can store information and instructions, or EEPROM, CD-ROM or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited thereto.

[0058] Optionally, the memory stores the code of the computer program that executes the scheme of this application, and the execution is controlled by the processor. The processor executes the application code stored in the memory to implement... Figure 8 The operation of the DC composite electric field calculation device provided in the illustrated embodiment.

[0059] Another embodiment of this application provides a computer-readable storage medium storing computer-executable instructions for performing the above-described... Figure 1 The method for calculating the DC composite electric field is shown.

[0060] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0061] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0062] The above is a detailed description of the preferred embodiments of this application. However, this application is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

[0063] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for calculating a DC composite electric field, characterized in that, Includes the following steps: Establish a standard k-ɛ model of the wind field around a building and calculate the turbulent flow conditions around the building. A nominal electric field calculation model for a high-voltage direct current (HVDC) line is established. The corona initiation status of the conductor is determined by comparing the surface electric field strength with the corona initiation field strength of the positive and negative conductors. This includes: using a simulated charge method combined with the image method, setting simulated charges within the conductor and at symmetrical positions with the ground as the baseline; selecting matching points on the conductor surface; calculating the simulated charge values ​​in the positive and negative conductors; solving for the electric field components in the x and y directions and the nominal electric field amplitude on the conductor surface based on the simulated charge values; calculating the corona initiation field strength using the Peek formula; and comparing the magnitude of the corona initiation field strength with the nominal electric field amplitude to determine the corona initiation status of the conductor. Based on the corona formation and turbulence conditions of the conductors, the initial values ​​of the surface charge density of the positive and negative conductors are estimated and corrected. Considering the upward flow of wind around the conductors, the Poisson equation and the current continuity equation are solved using the upstream finite element method to determine the electric field distribution and charge density distribution, until the charge density and field strength distribution stabilize; including: The initial value of the surface charge density of the conductor is estimated using the following formula: in, ε 0 is the vacuum dielectric constant. U c0 The corona initiation voltage of the conductor. E g This represents the maximum nominal ground field strength. U The operating voltage of the conductor. r The radius of the sub-conductor. h The height of the conductor above the ground. E c0 The corona field strength of the sub-conductor; The electric field distribution is solved by discretizing the Poisson equation using the finite element method. Using the upper flow element method and taking into account the wind speed around the building, the charge density distribution is solved; Determine if the charge density is stable. If it is not stable, repeat the solution for the electric field distribution and charge density distribution until it is stable. Calculate the maximum electric field strength on the conductor surface at this time and compare it with the positive and negative corona field strengths. If the error exceeds the specified limit, it is corrected. The correction formula is as follows: in ρ s ( n )and ρ s ( n- 1) respectively the first n Second and third n -1st surface charge density value, E m This represents the maximum amplitude of the electric field intensity on the surface of the conductor. E onset To induce dizziness, μ >0 is the correction factor; Based on the current charge density on the surface of the conductor, calculate the overall charge density and the distribution of the combined electric field intensity.

2. The method according to claim 1, characterized in that, The steps for establishing a standard k-ɛ model of the wind field around a building to calculate the turbulent conditions around the building include: The site and buildings are modeled and partitioned to calculate the inlet wind speed at different heights; Based on Boussinesq's eddy viscosity assumption and the inlet wind speeds at different heights, the standard k-ɛ model was used and solved using the finite element method to obtain the turbulence conditions around the building.

3. A DC composite electric field calculation device, comprising: The turbulence model calculation module can establish a standard k-ɛ model of the wind field around a building and calculate the turbulence conditions of the wind around the building; The corona initiation state judgment module can establish a nominal electric field calculation model for a high-voltage direct current line and determine the corona initiation status of the conductor by comparing the surface electric field strength of the conductor with the corona initiation field strength of the positive and negative conductors. It includes: a charge calculation element that uses a combination of simulated charge method and image method to set simulated charges within the conductor and at symmetrical positions with the ground as the baseline, selects matching points on the conductor surface, and calculates the simulated charge values ​​in the positive and negative conductors; a surface characterization electric field amplitude calculation element that can solve for the electric field components in the x and y directions of the conductor surface and the nominal electric field amplitude of the conductor surface based on the simulated charge values ​​in the positive and negative conductors; a corona initiation field strength solving element that can solve for the corona initiation field strength using the Peek formula; and a corona initiation status judgment element that can compare the magnitude of the corona initiation field strength and the nominal surface electric field amplitude to determine the corona initiation status of the conductor. The iterative calculation module can predict and correct the initial values ​​of the surface charge density of the positive and negative conductors based on the corona formation and turbulence conditions of the conductors. It uses the upstream finite element method, considering wind speed around the conductors, to solve the Poisson equation and the current continuity equation to determine the electric field distribution and charge density distribution until the charge density and field strength distribution stabilize. This includes an initial density prediction element capable of predicting the initial value of the surface charge density of the conductors; the formula used is: in, ε 0 is the vacuum dielectric constant. U c0 The corona initiation voltage of the conductor. E g This represents the maximum nominal ground field strength. U The operating voltage of the conductor. r The radius of the sub-conductor. h The height of the conductor above the ground. E c0 The corona field strength of the sub-conductor; The electric field solver uses the finite element method to discretize the Poisson equation and solve for the electric field distribution; the density distribution solver uses the upper flow element method, taking into account the wind speed around the building, to solve for the charge density distribution; it determines whether the charge density is stable, and if not, it repeats the solution for the electric field distribution and charge density distribution until it stabilizes; it calculates the maximum electric field strength on the conductor surface at this point and compares it with the positive and negative corona field strengths. If the error exceeds a specified limit, it is corrected using the following formula: in ρ s ( n )and ρ s ( n- 1) respectively the first n Second and third n -1st surface charge density value, E m This represents the maximum amplitude of the electric field intensity on the surface of the conductor. E onset To induce dizziness, μ >0 is the correction factor; The distributed calculation module can calculate the distribution of charge density and combined electric field intensity across the entire field based on the current charge density on the surface of the conductor.

4. The apparatus according to claim 3, characterized in that, The turbulence model calculation module includes: The analysis element can model and partition a field and a building, and calculate the inlet wind speed at different heights; The finite element analysis element can obtain the turbulent conditions around the building by using the standard k-ɛ model and solving it using the finite element method based on Boussinesq's eddy viscosity assumption.

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 claim 1 or 2.

6. A computer-readable storage medium storing computer-executable instructions for performing the method of claim 1 or 2.

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