Parallel power cable current sharing optimization method and device based on magnetic ring current shunt

Abstract

The application relates to the technical field of power cables, and discloses a parallel power cable current sharing optimization method and device based on a magnetic ring current shunt, wherein the method comprises the following steps: simulating a three-dimensional finite element model and determining a first simulation impedance; obtaining an equivalent circuit model, determining a theoretical impedance according to the equivalent circuit model, and determining a current impedance according to the theoretical impedance and the first simulation impedance; obtaining an electromagnetic field coupling model and determining magnetic ring compensation parameters, simulating the electromagnetic field coupling model according to the magnetic ring compensation parameters and the current impedance to determine an impedance compensation mapping relationship; determining an impedance compensation sensitivity matrix according to the impedance compensation mapping relationship, and setting the value of the magnetic ring compensation parameters to perform current sharing optimization on the parallel power cable. The application can quantize the mapping relationship between the magnetic ring compensation parameters of the magnetic ring current shunt and impedance compensation, thereby accurately generating an optimal compensation scheme, greatly improving the reliability of the parallel power cable, and being beneficial to realizing power transmission safety.

Description

Technical Field

[0001] This application relates to the field of power cable technology, and in particular to a method and apparatus for optimizing current sharing in parallel power cables based on a magnetic ring current sharer. Background Technology

[0002] To meet the surge in power transmission capacity demands brought about by urbanization and the integration of new energy sources into the grid, traditional overhead lines are gradually being replaced by high-voltage cables. To enhance overall power transmission capacity, multiple high-voltage cables of the same phase are typically connected in parallel to form a power cable network to meet the required transmission capacity.

[0003] However, in actual engineering projects where parallel power cables are laid underground or on the seabed, the limitations imposed by underground pipelines, geological conditions, or marine topography result in non-straight laying configurations. Consequently, the impedance differences in parallel power cables lead to uneven distribution of load current, which can easily cause local overheating faults and seriously affect the power transmission safety of parallel power cables. Summary of the Invention

[0004] This application provides a current sharing optimization method and apparatus for parallel power cables based on a magnetic ring current sharer. It solves the technical problem that uneven load current distribution due to impedance differences in parallel power cables easily leads to localized overheating faults, seriously affecting the transmission safety of parallel power cables. This application combines three-dimensional electromagnetic field simulation and equivalent circuit modeling to determine the impedance of the parallel power cables. Based on this, it simulates the electromagnetic field coupling between the magnetic ring current sharer and the parallel power cables to quantify the mapping relationship between the magnetic ring compensation parameters and impedance compensation of the magnetic ring current sharer. This allows for the precise generation of the optimal compensation scheme, enabling the current sharing optimization scheme to more accurately match different laying scenarios, greatly improving the reliability of parallel power cables and contributing to transmission safety.

[0005] To achieve the above objectives, the main technical solutions adopted in this application include:

[0006] In a first aspect, embodiments of this application provide a current sharing optimization method for parallel power cables based on a magnetic ring current sharer, the method comprising:

[0007] A three-dimensional finite element model of the parallel power cable is simulated, and the first simulated impedance of the parallel power cable is determined based on the first simulation result of the three-dimensional finite element model.

[0008] Obtain the equivalent circuit model of the parallel power cable, determine the theoretical impedance of the parallel power cable based on the equivalent circuit model, and determine the current impedance of the parallel power cable based on the theoretical impedance and the first simulated impedance.

[0009] An electromagnetic field coupling model between the magnetic ring current sharer and the parallel power cable is obtained, and several magnetic ring compensation parameters of the magnetic ring current sharer are determined. The electromagnetic field coupling model is simulated based on the several magnetic ring compensation parameters and the current impedance, so as to determine the impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance based on the second simulation result of the electromagnetic field coupling model.

[0010] The impedance compensation sensitivity matrix is ​​determined based on the impedance compensation mapping relationship, and the values ​​of the magnetic ring compensation parameters are set according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix to optimize the current sharing of the parallel power cables.

[0011] The current sharing optimization method for parallel power cables proposed in this application improves the accuracy of impedance analysis by determining the current impedance through three-dimensional finite element model simulation and equivalent circuit model calculation. Furthermore, based on the accurate determination of the current impedance, an electromagnetic field coupling model is established, and the impedance compensation mapping relationship between the magnetic ring compensation parameters and the current impedance is determined. This precisely quantifies the impact of changes in the magnetic ring compensation parameters of the magnetic ring current sharer on impedance compensation and current deviation improvement. Thus, the setting of the magnetic ring compensation parameters can be considered from a global perspective, and the impedance compensation sensitivity matrix is ​​used to improve the current sharing optimization efficiency. This allows for current sharing optimization of parallel power cables under complex operating conditions, significantly improving the uneven current distribution in parallel power cables, enhancing their reliability, and contributing to power transmission safety.

[0012] Optionally, in some embodiments of this application, the geometric parameters of the parallel power cable include cable busbar parameters, and the field model is set according to the cable busbar parameters to determine the cable busbar interface in the three-dimensional finite element model based on the setting results;

[0013] The step of determining the first simulated impedance of the parallel power cable based on the first simulation results of the three-dimensional finite element model includes:

[0014] A three-phase power frequency voltage excitation is applied at the cable busbar interface to obtain the first simulation result of the three-dimensional finite element model in response to the three-phase power frequency voltage excitation.

[0015] The impedance calculation parameters are determined based on the first simulation results, and the first simulation impedance is determined based on the impedance calculation parameters.

[0016] In this embodiment, a three-phase power frequency voltage excitation is applied at the cable busbar interface in a three-dimensional finite element model to simulate the excitation conditions of parallel power cables in actual operation. This makes the obtained first simulation results more consistent with the actual working conditions, thereby making the impedance calculation parameters and the first simulation impedance determined based on the first simulation results more accurate. This provides a precise data basis for setting magnetic ring compensation parameters to achieve current sharing optimization.

[0017] Optionally, in some embodiments of this application, obtaining the equivalent circuit model of the parallel power cable and determining the theoretical impedance of the parallel power cable based on the equivalent circuit model includes:

[0018] The parallel power cable is equivalent to several branches, which are used as the equivalent circuit model.

[0019] Determine the AC resistance parameters of several branches, and determine the equivalent self-impedance of several branches based on the AC resistance parameters;

[0020] Determine the equivalent mutual impedance between the branches, and determine the theoretical impedance based on the equivalent self-impedance and the equivalent mutual impedance.

[0021] In this embodiment, several cables are equivalent to several branches to obtain an equivalent circuit model. The equivalent circuit model is then solved to calculate the theoretical impedance, so that the first simulated impedance can be verified with the theoretical impedance, thereby improving the accuracy of impedance analysis of parallel power cables.

[0022] Optionally, in some embodiments of this application, determining the current impedance of the parallel power cable based on the theoretical impedance and the first simulated impedance includes:

[0023] Determine the verification error between the theoretical impedance and the first simulated impedance;

[0024] If the verification error meets the preset conditions, the theoretical impedance and the first simulated impedance are weighted and averaged, and the current impedance is determined based on the calculation result.

[0025] This application embodiment uses the verification error between the theoretical impedance and the first simulated impedance to determine whether the three-dimensional finite element model and the equivalent circuit model are accurate. If the verification error meets the preset conditions, the model is determined to be accurate. At the same time, the current impedance is determined by the weighted average calculation method, which further improves the accuracy of impedance analysis of parallel power cables and provides an accurate data basis for subsequent precise quantification of the impact of changes in the magnetic ring compensation parameters of the magnetic ring current sharer on the degree of impedance compensation and current deviation improvement.

[0026] Optionally, in some embodiments of this application, obtaining the electromagnetic field coupling model between the magnetic ring current sharer and the parallel power cable includes:

[0027] The three-dimensional finite element model is adjusted based on the current impedance;

[0028] A magnetic ring current equalizer model is constructed based on finite element simulation software, and the magnetic ring current equalizer model is added to the adjusted three-dimensional finite element model to obtain the electromagnetic field coupling model.

[0029] Optionally, in some embodiments of this application, the step of simulating the electromagnetic field coupling model based on a plurality of magnetic ring compensation parameters and the current impedance, so as to determine the impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance based on the second simulation result of the electromagnetic field coupling model, includes:

[0030] The values ​​of several magnetic ring compensation parameters are changed using the controlled variable method, and the electromagnetic field coupling model is simulated under different values ​​of the magnetic ring compensation parameters, so as to determine the second simulated impedance of the parallel power cable based on the second simulation results.

[0031] Based on the difference between the second simulated impedance and the current impedance, determine the impedance compensation amount corresponding to the magnetic ring compensation parameter with different values;

[0032] The magnetic ring compensation parameters and the impedance compensation amount are fitted to determine the mapping relationship between each magnetic ring compensation parameter and the impedance compensation for the current impedance based on the fitting results.

[0033] This application embodiment uses the controlled variable method to analyze the impedance compensation of each magnetic ring compensation parameter to the current impedance, and fits the mapping relationship between the change of magnetic ring compensation parameter and the impedance compensation value. This allows for precise quantification of the impact of the change of magnetic ring compensation parameter of the magnetic ring current sharer on impedance compensation. The impedance compensation mapping relationship can accurately characterize the impedance change caused by the value of the magnetic ring compensation parameter to the parallel power cable, which is beneficial for accurately setting the magnetic ring compensation parameter to achieve current sharing optimization of the parallel power cable.

[0034] Optionally, in some embodiments of this application, the magnetic ring compensation parameters include at least one of the magnetic ring thickness, magnetic ring height, and magnetic ring air gap opening angle of the magnetic ring current equalizer.

[0035] Optionally, in some embodiments of this application, determining the impedance compensation sensitivity matrix based on the impedance compensation mapping relationship includes:

[0036] The degree of influence of each of the magnetic ring compensation parameters on the impedance compensation of the parallel power cable is determined based on the impedance compensation mapping relationship.

[0037] The compensation sensitivity level is determined based on the degree of impact of the impedance compensation.

[0038] The impedance compensation sensitivity matrix is ​​generated based on the compensation sensitivity classification.

[0039] This application embodiment determines the degree of influence of each magnetic ring compensation parameter on the impedance compensation of the parallel power cable through impedance compensation mapping relationship, and then generates an impedance compensation sensitivity matrix based on the degree of impedance compensation influence. The impedance compensation sensitivity matrix is ​​used to characterize the quantitative relationship of the current sharing improvement effect of each magnetic ring compensation parameter, which is beneficial to improving the adjustment efficiency of the magnetic ring compensation parameters.

[0040] Optionally, in some embodiments of this application, setting the value of the magnetic ring compensation parameter according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix to optimize current sharing of the parallel power cable includes:

[0041] Determine the target flow rate and obtain the target impedance corresponding to the target flow rate;

[0042] The priority of the magnetic ring compensation parameters is determined based on the impedance compensation sensitivity matrix.

[0043] The value scheme of the magnetic ring compensation parameters is determined based on the target impedance, the current impedance, the impedance compensation mapping relationship, and the priority.

[0044] The values ​​of the magnetic ring compensation parameters are set according to the aforementioned value selection scheme so that the current flowing through the parallel power cable meets the target current sharing ratio.

[0045] By determining the priority of the magnetic ring compensation parameters, the order in which multiple magnetic ring compensation parameters are adjusted is clarified. Based on the impedance compensation mapping relationship, the values ​​of each magnetic ring compensation parameter are precisely set according to the priority order, thereby compensating the impedance of the parallel power cable from the current impedance to the target impedance. This not only further refines the dynamic control process of impedance compensation and improves the efficiency of current sharing optimization, but also makes the magnetic ring compensation parameter value scheme more adaptable to actual complex working conditions. This greatly improves the uneven current distribution in the parallel power cable, enhances the reliability of the parallel power cable, and contributes to achieving power transmission safety.

[0046] Secondly, embodiments of this application provide a current sharing optimization device for parallel power cables based on a magnetic ring current sharer, the device comprising:

[0047] The simulation impedance determination module is used to simulate the three-dimensional finite element model of the parallel power cable and determine the first simulation impedance of the parallel power cable based on the first simulation result of the three-dimensional finite element model.

[0048] The current impedance determination module is used to obtain the equivalent circuit model of the parallel power cable, determine the theoretical impedance of the parallel power cable based on the equivalent circuit model, and determine the current impedance of the parallel power cable based on the theoretical impedance and the first simulated impedance.

[0049] The impedance compensation mapping module is used to obtain the electromagnetic field coupling model between the magnetic ring current sharer and the parallel power cable, and to determine several magnetic ring compensation parameters of the magnetic ring current sharer. The electromagnetic field coupling model is simulated based on the several magnetic ring compensation parameters and the current impedance, so as to determine the impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance based on the second simulation result of the electromagnetic field coupling model.

[0050] The current sharing optimization module is used to determine the impedance compensation sensitivity matrix according to the impedance compensation mapping relationship, and set the value of the magnetic ring compensation parameter according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix, so as to optimize the current sharing of the parallel power cable.

[0051] The parallel power cable current sharing optimization device proposed in this application improves the accuracy of impedance analysis by determining the current impedance through a simulation impedance determination module and a current impedance determination module. Furthermore, based on the accurate determination of the current impedance, the impedance compensation mapping module determines the impedance compensation mapping relationship between the magnetic ring compensation parameters and the current impedance, precisely quantifying the impact of changes in the magnetic ring compensation parameters of the magnetic ring current sharer on impedance compensation and current deviation improvement. This allows the current sharing optimization module to consider the setting of the magnetic ring compensation parameters from a global perspective and improves the current sharing optimization efficiency by utilizing the impedance compensation sensitivity matrix. Consequently, it can optimize the current sharing of parallel power cables under complex operating conditions, significantly improving the uneven current distribution of parallel power cables, enhancing their reliability, and contributing to power transmission safety. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of the structure of parallel power cables in related technologies;

[0054] Figure 2 This is a flowchart illustrating a current sharing optimization method for parallel power cables based on a magnetic ring current sharer, as proposed in an embodiment of this application.

[0055] Figure 3 This is a schematic diagram of the modeling of a three-dimensional finite element model of the parallel power cable proposed in this application in one embodiment;

[0056] Figure 4 This is a schematic diagram of the magnetic ring current sharer in this application;

[0057] Figure 5 This is a schematic diagram of the simulation results of the impedance compensation effect of the magnetic ring current sharer on cable a1 in one embodiment of this application.

[0058] Figure 6 This is a schematic diagram of the simulation results of the impedance compensation effect of the magnetic ring current sharer on cable a1 in another embodiment of this application;

[0059] Figure 7 This is a schematic diagram of the simulation results of the impedance compensation effect of the magnetic ring current sharer on cable b1 in one embodiment of this application;

[0060] Figure 8 This is a schematic diagram of the simulation results of the impedance compensation effect of the magnetic ring current sharer on cable b1 in another embodiment of this application;

[0061] Figure 9 This is a schematic diagram of the simulation results of the impedance compensation effect of the magnetic ring current sharer on cable b1 in another embodiment of this application;

[0062] Figure 10 This is a schematic diagram of a current sharing optimization device for parallel power cables based on a magnetic ring current sharer, as proposed in an embodiment of this application. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] To meet the surging demand for power transmission capacity brought about by urbanization and the integration of new energy sources into the grid, traditional overhead lines are gradually being replaced by high-voltage cables. To improve overall transmission capacity, multiple high-voltage cables of the same phase are typically connected in parallel to form a power cable network to meet the required transmission capacity. For example... Figure 1As shown, the parallel power cable includes two cables, Cable1 and Cable2, connected in parallel, as well as a circuit breaker QF, a current transformer CT, and a voltage transformer PT.

[0065] In some applications, laying parallel power cables underground or on the seabed can significantly reduce space occupation and the impact of electromagnetic radiation on the surrounding environment. However, in actual projects where parallel power cables are laid underground or on the seabed, the limitations imposed by underground pipelines, geological conditions, or marine topography result in non-straight laying configurations, including complex conditions such as bending (insufficient minimum bending radius), twisting (local deformation caused by construction errors), or crossing (multiple cables crossing each other). These conditions disrupt the ideal electromagnetic symmetry, leading to uneven load current distribution due to impedance differences in the parallel power cables. At the same time, the electric field distortion in non-straight laying areas causes distortion of the induced voltage value of the metal sheath in some locations, which can easily accelerate insulation aging and cause local overheating faults, seriously affecting the power transmission safety of parallel power cables.

[0066] According to an embodiment of this application, an embodiment of a current sharing optimization method for parallel power cables based on a magnetic ring current sharer is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0067] This embodiment provides a current sharing optimization method for parallel power cables based on a magnetic ring current sharer, which can be used in high-voltage transmission systems containing the aforementioned parallel power cables. Figure 2 This is a flowchart of a current sharing optimization method for parallel power cables according to an embodiment of this application, such as... Figure 2 As shown, the process includes the following steps:

[0068] Step S1: Simulate the three-dimensional finite element model of the parallel power cable, and determine the first simulated impedance of the parallel power cable based on the first simulation results of the three-dimensional finite element model.

[0069] Specifically, this application embodiment establishes a three-dimensional finite element model based on finite element simulation software. This mainly includes building the electro-magnetic coupling environment of the cable, and geometric modeling of the busbar, cable, and soil domain. The continuous physical field is discretized into finite elements using the three-dimensional finite element model. By solving the Maxwell equations corresponding to the three-dimensional finite element model, the complex electromagnetic characteristics of the parallel power cable in three-dimensional space, such as magnetic field distortion, current distribution, and sheath voltage, are simulated to obtain a first simulation result. This first simulation result is then used to determine the first simulated impedance. The first simulation result characterizes the distribution of parameters such as current density and voltage of the parallel power cable, thus reflecting the impedance of the parallel power cable.

[0070] Step S3: Obtain the equivalent circuit model of the parallel power cable, determine the theoretical impedance of the parallel power cable based on the equivalent circuit model, and determine the current impedance of the parallel power cable based on the theoretical impedance and the first simulation impedance.

[0071] Specifically, in this embodiment, an equivalent circuit model of parallel power cables is built in MATLAB based on the cable parameters in actual engineering. In this equivalent circuit model, the electrical parameters of the parallel power cables are quantified into equivalent impedance parameters and equivalent inductive reactance parameters. The theoretical impedance is then calculated using these parameters. Furthermore, the theoretical impedance is used to verify the first simulated impedance, thereby reducing simulation errors and ensuring an accurate current impedance.

[0072] Step S5: Obtain the electromagnetic field coupling model between the magnetic ring current sharer and the parallel power cable, and determine several magnetic ring compensation parameters of the magnetic ring current sharer. Simulate the electromagnetic field coupling model based on the several magnetic ring compensation parameters and the current impedance, so as to determine the impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance based on the second simulation results of the electromagnetic field coupling model.

[0073] Specifically, this application embodiment utilizes an electromagnetic field coupling model between a magnetic ring current sharer and a parallel power cable to determine the mapping relationship between each magnetic ring compensation parameter and impedance compensation, thereby achieving precise quantification between the changes in magnetic ring current sharer parameters and the current sharing optimization effect, providing accurate quantitative basis for subsequent current sharing optimization of parallel power cables.

[0074] Step S7: Determine the impedance compensation sensitivity matrix based on the impedance compensation mapping relationship, and set the values ​​of the magnetic ring compensation parameters based on the impedance compensation mapping relationship and the impedance compensation sensitivity matrix to optimize the current sharing of the parallel power cables.

[0075] Specifically, in this embodiment, the impedance compensation sensitivity matrix is ​​determined based on the impedance compensation mapping relationship. The impedance compensation sensitivity matrix can characterize the quantitative relationship between the change of the magnetic ring current sharer parameters and the degree of improvement of the deflection rate. Thus, the magnetic ring compensation parameters of the magnetic ring current sharer are dynamically adjusted using the impedance compensation sensitivity matrix to improve the adjustment efficiency of the magnetic ring compensation parameters.

[0076] Therefore, the current sharing optimization method for parallel power cables provided in this embodiment determines the current impedance through three-dimensional finite element model simulation and equivalent circuit model calculation, which improves the accuracy of impedance analysis of parallel power cables. Under the premise of accurately determining the current impedance, an electromagnetic field coupling model is established and the impedance compensation mapping relationship between the magnetic ring compensation parameters and the current impedance is determined. This accurately quantifies the impact of changes in the magnetic ring compensation parameters of the magnetic ring current sharer on the degree of impedance compensation and current deviation improvement. Thus, the setting of the magnetic ring compensation parameters can be considered from a global perspective, and the current sharing optimization efficiency is improved by using the impedance compensation sensitivity matrix. In this way, current sharing optimization of parallel power cables can be achieved for complex working conditions, which greatly improves the uneven current distribution of parallel power cables, improves the reliability of parallel power cables, and is conducive to achieving power transmission safety.

[0077] In some embodiments of this application, the construction process of the above-mentioned three-dimensional finite element model includes:

[0078] First, a field model is constructed in the finite element simulation software based on Ampere's law and the law of conservation of current. Specifically, appropriate magnetization models, conductivity conduction models, and dielectric models are added during the field model construction process.

[0079] Subsequently, the above-mentioned field model was set according to the geometric parameters of the parallel power cables. Specifically, a specific model of the parallel power cables was built from aspects such as cable geometry, spatial distribution, and positional distribution between each phase of the parallel cables. Based on the material parameters of common cables in actual engineering, reasonable material parameters were set for the busbar, cable conductor, insulation, metal sheath, and outer sheath in the model. Finally, a reasonable soil resistivity was set, and a soil domain was created around the cable, with the boundary set as an infinite element domain to obtain a three-dimensional finite element model.

[0080] In one example of an embodiment of this application, a parallel power cable of model 64 / 110YJLW02 is used as an example. Its relevant parameters are shown in Table 1, and thus the following can be constructed: Figure 3 The three-dimensional finite element model shown includes six cables: a1, a2, b1, b2, c1, and c2.

[0081] Table 1

[0082]

[0083] Furthermore, the geometric parameters of the parallel power cables include the cable busbar parameters. The field model is set according to the cable busbar parameters to determine the cable busbar interface in the three-dimensional finite element model based on the setting results.

[0084] In some embodiments of this application, step S1 above further includes the following steps:

[0085] Step S11: Apply a three-phase power frequency voltage excitation at the cable busbar interface to obtain the first simulation result of the three-dimensional finite element model responding to the three-phase power frequency voltage excitation.

[0086] Specifically, this application embodiment simulates the operation of a three-dimensional finite element model under the excitation of a three-phase power frequency voltage to adapt to the actual working conditions of parallel power cables. During the simulation, the first simulation results can be displayed through heat maps, contour maps, etc. The heat maps or contour maps can reflect the current density and voltage distribution of the three-dimensional finite element model in response to the excitation of a three-phase power frequency voltage. That is, the first simulation results characterize the bias current situation of the three-dimensional finite element model in response to the excitation of a three-phase power frequency voltage.

[0087] Step S12: Determine the impedance calculation parameters based on the first simulation results, and determine the first simulation impedance based on the impedance calculation parameters.

[0088] Specifically, in this embodiment, the bias current condition is determined based on the first simulation result, and the impedance calculation parameters related to the bias current condition are extracted using a probe, thereby calculating the first simulated impedance using the open-circuit-short-circuit method. The open-circuit-short-circuit method is an experimental method for calculating cable impedance parameters by applying open-circuit and short-circuit boundary conditions. In this embodiment, for lines with bias current conditions, the open-circuit voltage, short-circuit voltage, line current, and other impedance calculation parameters can be extracted using a probe to obtain the first simulated impedance.

[0089] It should be noted that, in the embodiments of this application, the first simulated impedance is an impedance matrix that includes the simulated self-impedance and simulated mutual impedance between each cable. Taking six cable conductors a1, a2, b1, b2, c1 and c2 as an example, the first simulated impedance is shown in Table 2.

[0090] Table 2

[0091]

[0092] In this embodiment, a three-phase power frequency voltage excitation is applied at the cable busbar interface in a three-dimensional finite element model to simulate the excitation conditions of parallel power cables in actual operation. This makes the obtained first simulation results more consistent with the actual working conditions, thereby making the impedance calculation parameters and the first simulation impedance determined based on the first simulation results more accurate. This provides a precise data basis for setting magnetic ring compensation parameters to achieve current sharing optimization.

[0093] In some embodiments of this application, step S3 above further includes the following steps:

[0094] Step S31: The parallel power cables are equivalent to several branches, which are used as an equivalent circuit model.

[0095] Specifically, taking the parallel power cable including the six cables a1, a2, b1, b2, c1 and c2 mentioned above as an example, the cable cores of cables a1, a2, b1, b2, c1 and c2 are equivalent to six branches, and the corresponding metal sheaths na1, na2, nb1, nb2, nc1 and nc2 of each cable are equivalent to six branches. Each branch can be equivalent to electrical components such as resistance, capacitance and inductance with corresponding parameters based on the physical characteristics of the cable core / metal sheath material itself and the mutual coupling effect between cables. Thus, these branches are constructed into equivalent circuit models based on MATLAB.

[0096] Step S32: Determine the AC resistance parameters of several branches, so as to determine the equivalent self-impedance of several branches based on the AC resistance parameters.

[0097] Specifically, the cable core and the corresponding metal sheath are both equivalent to the superposition of AC resistance and self-inductance. Therefore, the AC resistance parameter of each branch is shown in the following formula (1):

[0098]

[0099] In the formula, The AC resistance parameters of the branch are... The DC resistance parameter of the branch is... This represents the cable type coefficient, where y = 1 for single-core, dual-core, and triple-core cables, and y = 1.5 for conduit cables. The skin effect coefficient, This is the proximity effect coefficient.

[0100] Furthermore, DC resistance parameters The calculation formula is shown in the following formula (2):

[0101]

[0102] In the formula, The resistivity of a conductor is expressed in Ω•m. The nominal cross-sectional area of ​​the conductor, in meters. 2 , This is the temperature coefficient of resistance at 20℃, in °C. -1 , The conductor temperature is expressed in °C.

[0103] Skin effect coefficient The calculation formula is shown in the following formula (3):

[0104]

[0105] In the formula, z is calculated as shown in formula (4) below:

[0106]

[0107] In the formula, The cable frequency is expressed in Hz. The first coefficient is for conductor type, where the conductor type of the cable is copper core. The value is 1.

[0108] Proximity effect coefficient The calculation formula is shown in the following formula (5):

[0109]

[0110] In the formula, The second coefficient is for conductor type, where the conductor type of the cable is copper core, aluminum core, sector, or ring. The value is 0.8. The radius of the conductor or shielding layer, in meters. The distance between the conductors is measured in meters (m).

[0111] Based on the above formulas (1) to (5), the AC resistance parameters of several branches can be calculated. Furthermore, the equivalent self-impedance of the i-th branch is calculated based on the following formula (6). for:

[0112]

[0113] In the formula, The AC resistance per unit length is the same as the above. Related, unit is Ω. Soil resistivity, measured in Ω•m. The equivalent diameter of the conductor / shield is in meters (m).

[0114] Step S33: Determine the equivalent mutual impedance between branches, and determine the theoretical impedance based on the equivalent self impedance and the equivalent mutual impedance.

[0115] Specifically, the equivalent self-impedance between the i-th branch and the j-th branch is calculated based on the following formula (7). for:

[0116]

[0117] In the formula, Let be the conductor / shield distance between the i-th branch and the j-th branch.

[0118] Furthermore, based on the equivalent self-impedance and equivalent self-impedance The theoretical impedance is obtained, that is, the theoretical impedance includes the equivalent self-impedance. and equivalent self-impedance The impedance matrix is ​​shown in Table 3. Taking six cables a1, a2, b1, b2, c1, and c2 as an example, the theoretical impedances are shown in Table 3.

[0119] Table 3

[0120]

[0121] Step S34: Determine the verification error between the theoretical impedance and the first simulated impedance. If the verification error meets the preset conditions, calculate the weighted average of the theoretical impedance and the first simulated impedance, and determine the current impedance based on the calculation result.

[0122] Specifically, the two impedance matrices shown in Tables 2 and 3 are compared. If the verification error determined by the comparison is less than a preset value, the verification error is determined to meet the preset condition, and the current impedance is obtained by weighted averaging. Preferably, if the verification error is less than 5%, the verification error meets the preset condition; otherwise, the three-dimensional finite element model and the equivalent circuit model need to be corrected.

[0123] For example, in the first simulated impedance, the core inductance of cable a1 was 0.0203 H / km, while in the theoretical impedance, it was 0.0223 H / km, resulting in a verification error of 8.97%. Subsequently, combining the theoretical basis of the formula derivation with the verification of various material and environmental parameters during the simulation, the cause was determined to be that the solution domain of the Comsol simulation was not set large enough, causing the equivalent Carson depth in the formula to not be effectively simulated in the model. Therefore, the solution domain size was corrected in the three-dimensional finite element model, setting the soil domain boundary to 1300m, and the core inductance of cable a1 was re-extracted as 0.0224 H / km, reducing the verification error to 0.4%.

[0124] Furthermore, the loop matrix equation of the equivalent circuit model can also be obtained based on Kirchhoff's voltage law, as shown in the following formula (8):

[0125] Formula (8);

[0126] In the formula, This represents the mutual impedance between metal sheaths na1 and na2; the mutual impedances between other metal sheaths can be deduced similarly. This represents the mutual impedance between cable conductor a1 and the metal sheath na2. The mutual impedances between other conductors and the metal sheath can be deduced similarly. This represents the mutual impedance between cable conductors a1 and c2; the mutual impedances between other conductors can be deduced similarly. to This represents the sheath current in the six branches from na1 to nc2 of the metallic sheath. to This represents the current flowing through the conductors in the six branches from conductor a1 to c2 of the cable. , and This indicates the three-phase voltage applied to both ends of the parallel cable.

[0127] The above current to The simulation results are cross-validated with the simulated current flowing through each cable obtained from the 3D finite element model to ensure the accuracy of the 3D finite element model and the equivalent circuit model, and to enable verification. to Analyze the current deviation of parallel power cables.

[0128] This application embodiment equates several cables to several branches to obtain an equivalent circuit model, and then solves the equivalent circuit model to calculate the theoretical impedance. This facilitates subsequent verification between the first simulated impedance and the theoretical impedance, thereby improving the accuracy of impedance analysis for parallel power cables. Furthermore, this application embodiment uses the verification error between the theoretical impedance and the first simulated impedance to determine the accuracy of the three-dimensional finite element model and the equivalent circuit model. If the verification error meets preset conditions, the model is deemed accurate. Simultaneously, the current impedance is determined through a weighted average calculation method, further improving the accuracy of impedance analysis for parallel power cables. This provides an accurate data foundation for subsequently precisely quantifying the impact of changes in the magnetic ring compensation parameters of the magnetic ring current sharer on impedance compensation and the degree of current deviation improvement.

[0129] In some embodiments of this application, step S5 above further includes the following steps:

[0130] Step S51: Adjust the three-dimensional finite element model according to the current impedance.

[0131] Specifically, the relevant parameters in the three-dimensional finite element model are set according to the current impedance determined in step S34.

[0132] Step S52: Construct a magnetic ring current equalizer model based on finite element simulation software, and add the magnetic ring current equalizer model to the adjusted three-dimensional finite element model to obtain an electromagnetic field coupling model.

[0133] Specifically, such as Figure 4As shown, the magnetic ring current equalizer includes magnets 101, 102, and 103, as well as fasteners 2, adjusting device 3, and housing 5. When magnets 101, 102, and 103 wrap around cable 4, their high permeability significantly increases the inductive reactance of cable 4. By adjusting the air gap width A, the magnetic reluctance of the magnetic circuit is changed, thereby dynamically adjusting the inductance value. The magnets are composed of multiple fan-shaped annular magnet blocks 101, 102, and 103 assembled into a ring shape surrounding the outside of cable 4. The magnet material is high-permeability silicon steel sheet or ferrite. Fasteners 2 are used to fix adjacent magnet blocks without air gaps. The adjusting device 3 includes a fixing element 31 and a regulator 32, which form a threaded or snap-fit ​​structure. The fixing element 31 is mounted on the housing 5 of the magnet block with an air gap. The regulator 32 is movably connected to the fixing element 31. By adjusting the air gap width A between adjacent magnet blocks, the inductive reactance is changed, thereby achieving impedance compensation. In addition, the cable near the magnet is equipped with an LCD display that serves as a current monitoring device to show the magnitude of the cable current.

[0134] This application embodiment utilizes finite element simulation software to construct a magnetic ring current sharer model. Based on Ampere's law and the law of conservation of current, appropriate magnetization, conductivity, and dielectric models are added during the field construction process. Based on this, and using... Figure 4 The structure shown demonstrates the construction of a geometric model for the magnetic ring current equalizer, with dimensional parameters suitable for the constructed cable model and material parameters conforming to actual engineering requirements.

[0135] The constructed magnetic ring current sharer model is then added to the adjusted three-dimensional finite element model, and the excitation of the three-phase power frequency voltage source is applied again to simulate the electromagnetic field coupling between the magnetic ring current sharer and the parallel power cable.

[0136] Step S53: Use the controlled variable method to change the values ​​of several magnetic ring compensation parameters, and simulate the electromagnetic field coupling model under different values ​​of the magnetic ring compensation parameters, so as to determine the second simulated impedance of the parallel power cable based on the second simulation results.

[0137] Specifically, the magnetic ring compensation parameters include at least one of the magnetic ring thickness, magnetic ring height, and magnetic ring air gap opening angle of the magnetic ring flow equalizer.

[0138] The effect of changes in the aforementioned magnetic ring compensation parameters on impedance compensation was simulated using finite element simulation software. For example, the magnetic ring thickness, air gap opening angle, and material parameters were kept constant in the simulation. Specifically, the inner diameter of the magnetic ring was set to 0.0363 m, the outer diameter to 0.05 m, and the air gap opening angle to 20°. The magnetic ring height was then changed to 0.01 m, 0.015 m, and 0.02 m, and the second simulation results and corresponding second simulation impedances were recorded. The specific process can be found in step S12 above. Similarly, the probe was used to extract the relevant impedance calculation parameters from the second simulation results, and the second simulation impedance was calculated using the open-circuit-short-circuit method.

[0139] Similarly, for the other magnetic ring compensation parameters, the value of one of the magnetic ring compensation parameters is changed while keeping the other magnetic ring compensation parameters unchanged, so as to determine the second simulation impedance through the second simulation results.

[0140] Step S54: Based on the difference between the second simulated impedance and the current impedance, determine the impedance compensation amount corresponding to different values ​​of the magnetic ring compensation parameter.

[0141] Specifically, the difference between the second simulated impedance and the current impedance characterizes the impedance compensation effect of the magnetic ring current sharer on the parallel power cable. It should be noted that in some embodiments of this application, the aforementioned impedance compensation amount is the equivalent compensation inductance value generated by the magnetic ring current sharer.

[0142] Taking the impedance compensation effect of the magnetic ring current sharer on cable a1 as an example, the second simulation result is as follows: Figure 5 and Figure 6 As shown, by Figure 5 It can be seen that the height of the magnetic ring is positively correlated with the compensating inductance, and the height of the magnetic ring mainly affects the self-inductance of the corresponding cable, while its effect on the compensation of the mutual inductance is negligible. Figure 6 It can be seen that when only cable a1 is equipped with a magnetic ring current sharer, its influence on the self-inductance of other phase cables around it is very small and can be basically ignored. At the same time, it can be observed that as the height of the magnetic ring increases, the self-inductance compensation value of the cable affected by the magnetic ring current sharer increases in a positive correlation.

[0143] Taking the impedance compensation effect of the magnetic ring current equalizer on cable a2 as an example, the second simulation result is as follows: Figures 7 to 9 As shown, where, Figure 7 This illustrates the effect of magnetic ring height on impedance compensation. Figure 8 This shows the effect of magnetic ring thickness on impedance compensation. Figure 9 This illustrates the effect of the air gap opening angle of the magnetic ring on impedance compensation.

[0144] Depend on Figure 7 It can be seen that as the height of the magnetic ring increases, the impedance compensation of the magnetic ring current sharer for cable a2 increases positively. From... Figure 8 It can be seen that as the thickness of the magnetic ring increases, the impedance compensation of the magnetic ring current sharer for cable a2 increases positively. From... Figure 9 It can be seen that as the opening angle of the air gap of the magnetic ring increases, the impedance compensation of the magnetic ring current sharer for cable a2 increases positively. Furthermore, the magnetic ring current sharer has no significant impact on the mutual inductance between cable a2 and other phase cables. That is, the impedance compensation effect of the magnetic ring current sharer for parallel power cables is mainly reflected in self-inductance compensation, and its influence on the mutual inductance value is negligible.

[0145] Step S55: Fit the magnetic ring compensation parameters and impedance compensation amount to determine the mapping relationship between each magnetic ring compensation parameter and the impedance compensation for the current impedance based on the fitting results.

[0146] Specifically, by fitting the magnetic ring compensation parameters and impedance compensation amounts, the influence of changes in the magnetic ring compensation parameters on impedance compensation can be quantified. Therefore, based on the aforementioned impedance compensation mapping relationship, the impedance compensation amounts corresponding to different values ​​of the magnetic ring compensation parameters can be determined.

[0147] This application embodiment uses the controlled variable method to analyze the impedance compensation of each magnetic ring compensation parameter to the current impedance, and fits the mapping relationship between the change of magnetic ring compensation parameter and the impedance compensation value. This allows for precise quantification of the impact of the change of magnetic ring compensation parameter of the magnetic ring current sharer on impedance compensation. The impedance compensation mapping relationship can accurately characterize the impedance change caused by the value of the magnetic ring compensation parameter to the parallel power cable, which is beneficial for accurately setting the magnetic ring compensation parameter to achieve current sharing optimization of the parallel power cable.

[0148] In some embodiments of this application, step S7 above further includes the following steps:

[0149] Step S71: Determine the degree of influence of each magnetic ring compensation parameter on the impedance compensation of the parallel power cable based on the impedance compensation mapping relationship.

[0150] Specifically, the aforementioned impedance compensation mapping relationship can be considered as a fitted relationship between the magnetic ring compensation parameters and the impedance compensation amount, and this fitted relationship is a positive correlation function. Therefore, the degree of influence of impedance compensation can be determined based on the slope of this fitted relationship. The larger the slope of the fitted relationship, the greater the influence of the change in the magnetic ring compensation parameters on the impedance compensation amount, that is, the more sensitive the impedance compensation amount is to the change in the magnetic ring compensation parameters.

[0151] The above impedance compensation mapping relationship can also be the impedance compensation amount corresponding to the magnetic ring compensation parameters that change by a preset step. Therefore, the greater the change in impedance compensation amount, the greater the influence of the change in the magnetic ring compensation parameter on the impedance compensation amount.

[0152] Step S72: Determine the compensation sensitivity level based on the degree of influence of impedance compensation.

[0153] Specifically, the magnitude of the impact of impedance compensation is set into compensation sensitivity levels. The higher the impact of impedance compensation, the higher the level of compensation sensitivity.

[0154] Step S73: Generate an impedance compensation sensitivity matrix based on the compensation sensitivity classification.

[0155] Specifically, the impedance compensation sensitivity matrix is ​​used to characterize the degree of influence of each magnetic ring compensation parameter on the impedance compensation of each phase cable. Therefore, in the subsequent current sharing optimization process, the magnetic ring compensation parameters with a greater degree of impedance compensation influence are adjusted first.

[0156] Step S74: Determine the target flow rate and obtain the target impedance corresponding to the target flow rate.

[0157] For example, the adjusted three-dimensional finite element model is simulated to obtain the simulated current flowing through each cable corresponding to the current impedance, and the current imbalance is determined to be 15% based on the simulated current. The target current equalization is determined to be 5%, thereby determining the target impedance corresponding to the 5% target current equalization.

[0158] Step S75: Determine the priority of the magnetic ring compensation parameters based on the impedance compensation sensitivity matrix.

[0159] Specifically, if a small change in a parameter representing a magnetic ring compensation in the impedance compensation sensitivity matrix can cause a large change in impedance compensation, thus significantly affecting the current sharing effect, then that magnetic ring compensation parameter has a high priority during adjustment. Conversely, if a parameter change has little impact on impedance compensation and current sharing, its priority is low.

[0160] When optimizing current sharing of parallel power cables, the magnetic ring compensation parameters that have a more significant impact on the current sharing effect can be adjusted first according to the actual working conditions, thereby achieving the current sharing optimization goal more efficiently, avoiding blind parameter adjustment, and improving the efficiency and accuracy of the entire current sharing optimization process.

[0161] Step S76: Determine the value scheme of the magnetic ring compensation parameters based on the target impedance, current impedance, impedance compensation mapping relationship and priority.

[0162] Specifically, the amount to be compensated is determined based on the difference between the target impedance and the current impedance. Then, the adjustment order of each magnetic ring compensation parameter is determined according to priority: first, the magnetic ring height is adjusted, then the magnetic ring thickness is adjusted, and finally the magnetic ring air gap opening angle is adjusted. Based on the impedance compensation mapping relationship, the value scheme of magnetic ring height, magnetic ring thickness and magnetic ring air gap opening angle is determined so that the impedance compensation amount corresponding to the value scheme can meet the above-mentioned amount to be compensated.

[0163] For example, to reduce the current imbalance from 15% to 5%, finite element simulation parameter scanning and numerical calculations determine that the self-inductance of cable a2 needs to be compensated to be 222.69 nH / m. Based on the impedance compensation mapping relationship obtained from previous simulations, a set of values ​​is obtained: the magnetic ring height is 0.025m, the magnetic ring thickness is 0.055m, and the magnetic ring air gap opening angle is 10°.

[0164] Step S77: Set the values ​​of the magnetic ring compensation parameters according to the value selection scheme so that the current flowing through the parallel power cable meets the target current sharing.

[0165] Specifically, the above value scheme is applied to the magnetic ring current sharer corresponding to each phase cable to verify through simulation whether the current imbalance has decreased from 15% to 5%. If the target current sharing ratio is not achieved, the above magnetic ring compensation parameters are adjusted until the target current sharing ratio requirement is met.

[0166] This application embodiment determines the degree of influence of each magnetic ring compensation parameter on the impedance compensation of parallel power cables through impedance compensation mapping relationship, and then generates an impedance compensation sensitivity matrix based on the degree of impedance compensation influence. The impedance compensation sensitivity matrix is ​​then used to characterize the quantitative relationship of the current sharing improvement effect of each magnetic ring compensation parameter, which is beneficial to improving the adjustment efficiency of magnetic ring compensation parameters.

[0167] Furthermore, by determining the priority of the magnetic ring compensation parameters, the order in which multiple magnetic ring compensation parameters are adjusted is clarified. Thus, based on the impedance compensation mapping relationship, the values ​​of each magnetic ring compensation parameter are precisely set according to the priority order, thereby compensating the impedance of the parallel power cable from the current impedance to the target impedance. This not only further refines the dynamic control process of impedance compensation and improves the efficiency of current sharing optimization, but also makes the magnetic ring compensation parameter value scheme more adaptable to actual complex working conditions. This greatly improves the uneven current distribution in the parallel power cable, enhances the reliability of the parallel power cable, and contributes to achieving power transmission safety.

[0168] Accordingly, please refer to Figure 10 This application provides a current sharing optimization device for parallel power cables based on a magnetic ring current sharer. The device includes:

[0169] The simulation impedance determination module 810 is used to simulate the three-dimensional finite element model of the parallel power cable and determine the first simulation impedance of the parallel power cable based on the first simulation result of the three-dimensional finite element model.

[0170] The current impedance determination module 820 is used to obtain the equivalent circuit model of the parallel power cable, determine the theoretical impedance of the parallel power cable based on the equivalent circuit model, and determine the current impedance of the parallel power cable based on the theoretical impedance and the first simulation impedance.

[0171] The impedance compensation mapping module 830 is used to obtain the electromagnetic field coupling model between the magnetic ring current sharer and the parallel power cable, and to determine several magnetic ring compensation parameters of the magnetic ring current sharer. Based on the several magnetic ring compensation parameters and the current impedance, the electromagnetic field coupling model is simulated, so as to determine the impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance based on the second simulation result of the electromagnetic field coupling model.

[0172] The current sharing optimization module 840 is used to determine the impedance compensation sensitivity matrix based on the impedance compensation mapping relationship, and to set the values ​​of the magnetic ring compensation parameters based on the impedance compensation mapping relationship and the impedance compensation sensitivity matrix, so as to optimize the current sharing of parallel power cables.

[0173] In some embodiments of this application, the simulation impedance determination module 810 further includes:

[0174] The first simulation unit 811 is used to apply a three-phase power frequency voltage excitation at the cable busbar interface to obtain the first simulation result of the three-dimensional finite element model responding to the three-phase power frequency voltage excitation.

[0175] The first calculation unit 812 is used to determine the impedance calculation parameters based on the first simulation results, and to determine the first simulation impedance based on the impedance calculation parameters.

[0176] In some embodiments of this application, the current impedance determination module 820 further includes:

[0177] The equivalent circuit modeling unit 821 is used to convert several parallel power cables into several branches as equivalent circuit models.

[0178] The second calculation unit 822 is used to determine the AC resistance parameters of several branches, so as to determine the equivalent self-impedance of several branches based on the AC resistance parameters.

[0179] The third calculation unit 823 is used to determine the equivalent mutual impedance between branches and to determine the theoretical impedance based on the equivalent self impedance and the equivalent mutual impedance.

[0180] The verification unit 824 is used to determine the verification error between the theoretical impedance and the first simulated impedance. When the verification error meets the preset conditions, the theoretical impedance and the first simulated impedance are weighted and averaged, and the current impedance is determined based on the calculation result.

[0181] In some embodiments of this application, the impedance compensation mapping module 830 further includes:

[0182] The coupling modeling unit 831 is used to adjust the three-dimensional finite element model according to the current impedance, construct a magnetic ring current equalizer model based on finite element simulation software, and add the magnetic ring current equalizer model to the adjusted three-dimensional finite element model to obtain the electromagnetic field coupling model.

[0183] The second simulation unit 832 is used to change the values ​​of several magnetic ring compensation parameters using the control variable method, and to simulate the electromagnetic field coupling model under different values ​​of the magnetic ring compensation parameters, so as to determine the second simulation impedance of the parallel power cable based on the second simulation results.

[0184] The mapping determination unit 833 is used to determine the impedance compensation amount corresponding to different values ​​of the magnetic ring compensation parameter based on the difference between the second simulated impedance and the current impedance, and to fit the magnetic ring compensation parameter and the impedance compensation amount to determine the impedance compensation mapping relationship between each magnetic ring compensation parameter and the current impedance based on the fitting result.

[0185] In some embodiments of this application, the current sharing optimization module 840 further includes:

[0186] The sensitivity determination unit 841 is used to determine the degree of influence of each magnetic ring compensation parameter on the impedance compensation of the parallel power cable according to the impedance compensation mapping relationship, determine the compensation sensitivity level according to the degree of impedance compensation influence, and generate the impedance compensation sensitivity matrix according to the compensation sensitivity level.

[0187] The value selection unit 842 is used to determine the target flow rate and obtain the target impedance corresponding to the target flow rate. It determines the priority of the magnetic ring compensation parameters according to the impedance compensation sensitivity matrix, and determines the value selection scheme of the magnetic ring compensation parameters according to the target impedance, the current impedance, the impedance compensation mapping relationship and the priority.

[0188] The optimization unit 843 is used to set the value of the magnetic ring compensation parameter according to the value selection scheme so that the current flowing through the parallel power cable meets the target current sharing.

[0189] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0190] In this embodiment, the parallel power cable current sharing optimization device is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0191] This application provides a computer device comprising one or more processors, memory, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components are interconnected via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processor can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system).

[0192] The processor can be a central processing unit, a network processor, or a combination thereof. The processor may further include hardware chips. These hardware chips can be application-specific integrated circuits (ASICs), programmable logic devices (PLDs), or combinations thereof. The programmable logic devices can be complex programmable logic devices (CLPs), field-programmable gate arrays (FPGAs), general-purpose array logic (GDAs), or any combination thereof.

[0193] The memory stores instructions executable by at least one processor to cause the at least one processor to perform the method shown in the above embodiments.

[0194] The memory may include a stored program area and a stored data area, wherein the stored program area may store the operating system and application programs required for at least one function; the stored data area may store data created based on the use of the computer device, etc. Furthermore, the memory may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory may optionally include memory remotely located relative to the processor, which can be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0195] The memory may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0196] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0197] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0198] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0199] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0200] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0201] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0202] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

[0203] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A current sharing optimization method for parallel power cables based on a magnetic ring current sharer, characterized in that, The method includes: A three-dimensional finite element model of the parallel power cable is simulated, and the first simulated impedance of the parallel power cable is determined based on the first simulation result of the three-dimensional finite element model. Obtain the equivalent circuit model of the parallel power cable, determine the theoretical impedance of the parallel power cable based on the equivalent circuit model, and determine the current impedance of the parallel power cable based on the theoretical impedance and the first simulated impedance. An electromagnetic field coupling model between the magnetic ring current sharer and the parallel power cable is obtained, and several magnetic ring compensation parameters of the magnetic ring current sharer are determined. The electromagnetic field coupling model is simulated based on the several magnetic ring compensation parameters and the current impedance, so as to determine the impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance based on the second simulation result of the electromagnetic field coupling model. The impedance compensation sensitivity matrix is ​​determined based on the impedance compensation mapping relationship, and the values ​​of the magnetic ring compensation parameters are set according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix to optimize the current sharing of the parallel power cables.

2. The method according to claim 1, characterized in that, The geometric parameters of the parallel power cable include the cable busbar parameters. The pre-constructed field model is set according to the cable busbar parameters, so as to determine the cable busbar interface in the three-dimensional finite element model based on the setting results. The step of determining the first simulated impedance of the parallel power cable based on the first simulation results of the three-dimensional finite element model includes: A three-phase power frequency voltage excitation is applied at the cable busbar interface to obtain the first simulation result of the three-dimensional finite element model in response to the three-phase power frequency voltage excitation. The impedance calculation parameters are determined based on the first simulation results, and the first simulation impedance is determined based on the impedance calculation parameters.

3. The method according to claim 1, characterized in that, The step of obtaining the equivalent circuit model of the parallel power cable and determining the theoretical impedance of the parallel power cable based on the equivalent circuit model includes: The parallel power cable is equivalent to several branches, which are used as the equivalent circuit model. Determine the AC resistance parameters of several branches, and determine the equivalent self-impedance of several branches based on the AC resistance parameters; Determine the equivalent mutual impedance between the branches, and determine the theoretical impedance based on the equivalent self-impedance and the equivalent mutual impedance.

4. The method according to claim 1, characterized in that, Determining the current impedance of the parallel power cable based on the theoretical impedance and the first simulated impedance includes: Determine the verification error between the theoretical impedance and the first simulated impedance; If the verification error meets the preset conditions, the theoretical impedance and the first simulated impedance are weighted and averaged, and the current impedance is determined based on the calculation result.

5. The method according to claim 1, characterized in that, The process of obtaining the electromagnetic field coupling model between the magnetic ring current sharer and the parallel power cable includes: The three-dimensional finite element model is adjusted based on the current impedance; A magnetic ring current equalizer model is constructed based on finite element simulation software, and the magnetic ring current equalizer model is added to the adjusted three-dimensional finite element model to obtain the electromagnetic field coupling model.

6. The method according to claim 1, characterized in that, The step of simulating the electromagnetic field coupling model based on several magnetic ring compensation parameters and the current impedance, and determining the impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance based on the second simulation results of the electromagnetic field coupling model, includes: The values ​​of several magnetic ring compensation parameters are changed using the controlled variable method, and the electromagnetic field coupling model is simulated under different values ​​of the magnetic ring compensation parameters, so as to determine the second simulated impedance of the parallel power cable based on the second simulation results. Based on the difference between the second simulated impedance and the current impedance, determine the impedance compensation amount corresponding to the magnetic ring compensation parameter with different values; The magnetic ring compensation parameters and the impedance compensation amount are fitted to determine the mapping relationship between each magnetic ring compensation parameter and the impedance compensation for the current impedance based on the fitting results.

7. The method according to claim 1 or 6, characterized in that, The magnetic ring compensation parameters include at least one of the magnetic ring thickness, magnetic ring height, and magnetic ring air gap opening angle of the magnetic ring current equalizer.

8. The method according to claim 1, characterized in that, Determining the impedance compensation sensitivity matrix based on the impedance compensation mapping relationship includes: The degree of influence of each of the magnetic ring compensation parameters on the impedance compensation of the parallel power cable is determined based on the impedance compensation mapping relationship. The compensation sensitivity level is determined based on the degree of impact of the impedance compensation. The impedance compensation sensitivity matrix is ​​generated based on the compensation sensitivity classification.

9. The method according to claim 1, characterized in that, The step of setting the values ​​of the magnetic ring compensation parameters according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix to optimize current sharing of the parallel power cables includes: Determine the target flow rate and obtain the target impedance corresponding to the target flow rate; The priority of the magnetic ring compensation parameters is determined based on the impedance compensation sensitivity matrix. The value scheme of the magnetic ring compensation parameters is determined based on the target impedance, the current impedance, the impedance compensation mapping relationship, and the priority. The values ​​of the magnetic ring compensation parameters are set according to the aforementioned value selection scheme so that the current flowing through the parallel power cable meets the target current sharing ratio.

10. A current sharing optimization device for parallel power cables based on a magnetic ring current sharer, characterized in that, The device includes: The simulation impedance determination module is used to simulate the three-dimensional finite element model of the parallel power cable and determine the first simulation impedance of the parallel power cable based on the first simulation result of the three-dimensional finite element model. The current impedance determination module is used to obtain the equivalent circuit model of the parallel power cable, determine the theoretical impedance of the parallel power cable based on the equivalent circuit model, and determine the current impedance of the parallel power cable based on the theoretical impedance and the first simulated impedance. The impedance compensation mapping module is used to obtain the electromagnetic field coupling model between the magnetic ring current sharer and the parallel power cable, and to determine several magnetic ring compensation parameters of the magnetic ring current sharer. The electromagnetic field coupling model is simulated based on the several magnetic ring compensation parameters and the current impedance, so as to determine the impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance based on the second simulation result of the electromagnetic field coupling model. The current sharing optimization module is used to determine the impedance compensation sensitivity matrix according to the impedance compensation mapping relationship, and set the value of the magnetic ring compensation parameter according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix, so as to optimize the current sharing of the parallel power cable.

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