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

Abstract

The invention 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 equalizer, and the method comprises the steps: carrying out the simulation of a three-dimensional finite element model, and determining first simulation impedance; obtaining an equivalent circuit model, determining theoretical impedance according to the equivalent circuit model, and determining current impedance according to the theoretical impedance and the first simulation impedance; obtaining an electromagnetic field coupling model, determining a magnetic ring compensation parameter, and simulating the electromagnetic field coupling model according to the magnetic ring compensation parameter and the current impedance to determine an impedance compensation mapping relation; and determining an impedance compensation sensitivity matrix according to the impedance compensation mapping relation, and setting values of magnetic ring compensation parameters so as to perform current sharing optimization on the parallel power cables. According to the invention, the mapping relation between the magnetic ring compensation parameter and impedance compensation of the magnetic ring current equalizer can be quantified, thereby accurately generating an optimal compensation scheme, greatly improving the reliability of the parallel power cable, and facilitating the realization of power transmission safety.

Description

Technical Field

[0001] The present application relates to the technical field of power cables, and in particular to a method and device for optimizing current equalization of parallel power cables based on a magnetic ring current equalizer. Background Art

[0002] To meet the surge in transmission capacity driven by urbanization and the integration of renewable energy sources, traditional overhead lines are being replaced by high-voltage cables. To increase overall transmission capacity, multiple high-voltage cables in the same phase are often connected in parallel to meet transmission capacity requirements.

[0003] However, in actual underground or submarine laying projects, parallel power cables are restricted by underground pipelines, geological conditions or marine topography, resulting in non-straight laying patterns. As a result, the load current of the parallel power cables is unevenly distributed due to impedance differences, which can easily cause local overheating failures and seriously affect the power transmission safety of the parallel power cables. Summary of the Invention

[0004] The present application provides a method and device for optimizing the current sharing of parallel power cables based on a magnetic ring current equalizer, which solves the technical problem that the load current of parallel power cables is unevenly distributed due to impedance differences, which in turn easily causes local overheating failures and seriously affects the power transmission safety of the parallel power cables. The present application combines three-dimensional electromagnetic field simulation and equivalent circuit modeling to determine the impedance of the parallel power cables, and on this basis simulates the electromagnetic field coupling between the magnetic ring current equalizer and the parallel power cables to quantify the mapping relationship between the magnetic ring compensation parameters of the magnetic ring current equalizer and the impedance compensation, thereby accurately generating the optimal compensation scheme, so that the current sharing optimization scheme can more accurately match different laying scenarios, greatly improving the reliability of the parallel power cables, and facilitating power transmission safety.

[0005] In order to achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, an embodiment of the present application provides a method for optimizing current sharing of parallel power cables based on a magnetic ring current equalizer, the method comprising: Simulating a three-dimensional finite element model of the parallel power cables, and determining a first simulated impedance of the parallel power cables according to a first simulation result of the three-dimensional finite element model; Obtaining an equivalent circuit model of the parallel power cables, determining a theoretical impedance of the parallel power cables according to the equivalent circuit model, and determining a current impedance of the parallel power cables according to the theoretical impedance and the first simulated impedance; acquire an electromagnetic field coupling model between the magnetic ring current equalizer and the parallel power cable, and determine a plurality of magnetic ring compensation parameters of the magnetic ring current equalizer, simulate the electromagnetic field coupling model according to the plurality of magnetic ring compensation parameters and the current impedance, to determine an impedance compensation mapping relationship of each magnetic ring compensation parameter to the current impedance according to a second simulation result of the electromagnetic field coupling model; determine an impedance compensation sensitivity matrix according to the impedance compensation mapping relationship, and set a value of the magnetic ring compensation parameter according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix, to perform current equalization optimization on the parallel power cable.

[0006] The parallel power cable current equalization optimization method provided by the embodiments of the present application determines the current impedance through three-dimensional finite element model simulation and equivalent circuit model calculation, improves the accuracy of parallel power cable impedance analysis, and on the premise of accurately determining the current impedance, establishes an electromagnetic field coupling model, determines the impedance compensation mapping relationship of the magnetic ring compensation parameter to the current impedance, accurately quantifies the influence of the magnetic ring compensation parameter change of the magnetic ring current equalizer on the impedance compensation and the current deviation improvement, so that the setting of the magnetic ring compensation parameter can be considered from a global perspective, the impedance compensation sensitivity matrix is used to improve the current equalization optimization efficiency, and thus the current equalization optimization of the parallel power cable can be realized under complex working conditions, the uneven current distribution of the parallel power cable is greatly improved, the reliability of the parallel power cable is improved, and power transmission safety is facilitated.

[0007] Optionally, in some embodiments of the present application, the geometric parameters of the parallel power cable include cable busbar parameters, the field model is set according to the cable busbar parameters, and a cable busbar interface in the three-dimensional finite element model is determined according to a setting result; The first simulation impedance of the parallel power cable is determined according to the first simulation result of the three-dimensional finite element model, including: a power frequency three-phase voltage excitation is applied at the cable busbar interface, to acquire a first simulation result of the three-dimensional finite element model in response to the power frequency three-phase voltage excitation; impedance calculation parameters are determined according to the first simulation result, and the first simulation impedance is determined based on the impedance calculation parameters.

[0008] The embodiments of the present application apply a power frequency three-phase voltage excitation at the cable busbar interface in the three-dimensional finite element model, to simulate the excitation condition of the parallel power cable in actual operation, so that the acquired first simulation result is more consistent with the actual working condition, and thus the impedance calculation parameters and the first simulation impedance determined based on the first simulation result are more accurate, providing an accurate data basis for subsequent setting of the magnetic ring compensation parameter to realize current equalization optimization.

[0009] Optionally, in some embodiments of the present application, the obtaining the equivalent circuit model of the parallel power cable, determining the theoretical impedance of the parallel power cable according to the equivalent circuit model comprises: equivalent circuit model of the parallel power cable is equivalent to a plurality of branches; determining the AC resistance parameters of a plurality of the branches to determine the equivalent self-impedance of a plurality of the branches according to the AC resistance parameters; determining the equivalent mutual-impedance between the branches, and determining the theoretical impedance according to the equivalent self-impedance and the equivalent mutual-impedance.

[0010] The embodiments of the present application equivalent circuit model of the parallel power cable is equivalent to a plurality of branches to obtain the equivalent circuit model, and then the equivalent circuit model is calculated to obtain the theoretical impedance, so as to facilitate the subsequent verification of the first simulation impedance and the theoretical impedance, thereby improving the accuracy of the parallel power cable impedance analysis.

[0011] Optionally, in some embodiments of the present application, the determining the current impedance of the parallel power cable according to the theoretical impedance and the first simulation impedance comprises: determining the verification error between the theoretical impedance and the first simulation impedance; in the case where the verification error meets the preset condition, weighted mean calculation is performed on the theoretical impedance and the first simulation impedance, and the current impedance is determined according to the calculation result.

[0012] The embodiments of the present application use the verification error between the theoretical impedance and the first simulation impedance to determine whether the three-dimensional finite element model and the equivalent circuit model are accurate, and in the case where the verification error meets the preset condition, the model is determined to be accurate, and the current impedance is determined by weighted mean calculation, further improving the accuracy of the parallel power cable impedance analysis, and providing accurate data basis for subsequent accurate quantification of the influence of the magnetic ring compensator magnetic ring compensation parameter change on impedance compensation and flow deviation improvement.

[0013] Optionally, in some embodiments of the present application, the obtaining the electromagnetic field coupling model between the magnetic ring current sharing device and the parallel power cable comprises: adjusting the three-dimensional finite element model according to the current impedance; constructing a magnetic ring current sharing device model based on a finite element simulation software, and adding the magnetic ring current sharing device model to the adjusted three-dimensional finite element model to obtain the electromagnetic field coupling model.

[0014] Optionally, in some embodiments of the present application, simulating the electromagnetic field coupling model according to the plurality of magnetic ring compensation parameters and the current impedance, so as to determine an impedance compensation mapping relationship between each magnetic ring compensation parameter and the current impedance according to a second simulation result of the electromagnetic field coupling model, includes: using a control variable method to change the values ​​of several magnetic ring compensation parameters, and simulating the electromagnetic field coupling model when the magnetic ring compensation parameters are at different values, so as to determine a second simulated impedance of the parallel power cable according to the second simulation result; determining impedance compensation amounts corresponding to different values ​​of the magnetic ring compensation parameters according to a difference between the second simulated impedance and the current impedance; The magnetic ring compensation parameters and the impedance compensation amount are fitted to determine a mapping relationship between each of the magnetic ring compensation parameters and the impedance compensation for the current impedance according to a fitting result.

[0015] The embodiment of the present application uses the control 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 the magnetic ring compensation parameter and the impedance compensation value, so as to accurately quantify the impact of the change of the magnetic ring compensation parameter of the magnetic ring current equalizer on the impedance compensation, so that 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 conducive to accurately setting the magnetic ring compensation parameters to achieve current sharing optimization of the parallel power cables.

[0016] Optionally, in some embodiments of the present application, the magnetic ring compensation parameter includes at least one of a magnetic ring thickness, a magnetic ring height, and a magnetic ring air gap opening angle of the magnetic ring current equalizer.

[0017] Optionally, in some embodiments of the present application, determining an impedance compensation sensitivity matrix according to the impedance compensation mapping relationship includes: Determining the influence of each of the magnetic ring compensation parameters on the impedance compensation of the parallel power cables according to the impedance compensation mapping relationship; Determining a compensation sensitivity classification according to the degree of influence of the impedance compensation; The impedance compensation sensitivity matrix is ​​generated according to the compensation sensitivity classification.

[0018] The embodiment of the present application determines the degree of influence of each magnetic ring compensation parameter on the impedance compensation of the parallel power cable through the impedance compensation mapping relationship, and then generates an impedance compensation sensitivity matrix based on the impedance compensation influence degree, so as to use the impedance compensation sensitivity matrix to characterize the quantitative relationship of each magnetic ring compensation parameter on the current sharing improvement effect, which is conducive to improving the adjustment efficiency of the magnetic ring compensation parameters.

[0019] Optionally, in some embodiments of the present 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 the current sharing of the parallel power cables includes: Determining a target flow rate and obtaining a target impedance corresponding to the target flow rate; Determining the priority of the magnetic ring compensation parameters according to the impedance compensation sensitivity matrix; Determining a value scheme for the magnetic ring compensation parameter according to the target impedance, the current impedance, the impedance compensation mapping relationship, and the priority; The value of the magnetic ring compensation parameter is set according to the value scheme so that the current flowing through the parallel power cables meets the target current sharing degree.

[0020] By determining the priority of the magnetic ring compensation parameters, the adjustment order of multiple magnetic ring compensation parameters is clarified, so that the values ​​of each magnetic ring compensation parameter can be accurately set according to the priority order based on the impedance compensation mapping relationship, so that the impedance of the parallel power cable is compensated from the current impedance to the target impedance. This not only further refines the dynamic control process of impedance compensation and improves the current sharing optimization efficiency, but also makes the value scheme of the magnetic ring compensation parameters more adaptable to actual complex working conditions, 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.

[0021] In a second aspect, an embodiment of the present application provides a parallel power cable current equalization optimization device based on a magnetic ring current equalizer, the device comprising: a simulated impedance determination module, configured to simulate a three-dimensional finite element model of the parallel power cables and determine a first simulated impedance of the parallel power cables according to a first simulation result of the three-dimensional finite element model; a current impedance determination module, configured to obtain an equivalent circuit model of the parallel power cables, determine a theoretical impedance of the parallel power cables according to the equivalent circuit model, and determine a current impedance of the parallel power cables according to the theoretical impedance and the first simulated impedance; an impedance compensation mapping module, configured to obtain an electromagnetic field coupling model between the magnetic ring current equalizer and the parallel power cable, determine a plurality of magnetic ring compensation parameters of the magnetic ring current equalizer, simulate the electromagnetic field coupling model according to the plurality of magnetic ring compensation parameters and the current impedance, and determine an impedance compensation mapping relationship between each of the magnetic ring compensation parameters and the current impedance according to a second simulation result of the electromagnetic field coupling model; A current sharing optimization module is used to determine an 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 to optimize the current sharing of the parallel power cables.

[0022] The parallel power cable current sharing optimization device proposed in the embodiment of the present application determines the current impedance through a simulation impedance determination module and a current impedance determination module, thereby improving the accuracy of the impedance analysis of the parallel power cable. On the premise of accurately determining the current impedance, the impedance compensation mapping relationship between the magnetic ring compensation parameters and the current impedance is determined through the impedance compensation mapping module, and the influence of the change of the magnetic ring compensation parameters of the magnetic ring current equalizer on the impedance compensation and the degree of improvement of the bias current is accurately quantified, so that the current sharing optimization module can consider the setting of the magnetic ring compensation parameters from a global perspective, and use the impedance compensation sensitivity matrix to improve the current sharing optimization efficiency, thereby realizing the current sharing optimization of the parallel power cables for complex working conditions, greatly improving the uneven current distribution of the parallel power cables, improving the reliability of the parallel power cables, and facilitating the realization of power transmission safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 Schematic diagram of the structure of parallel power cables in related technology; Figure 2 A schematic diagram of a flow chart of a method for optimizing current sharing of parallel power cables based on a magnetic ring current equalizer proposed in an embodiment of the present application; Figure 3 This is a schematic diagram of modeling a three-dimensional finite element model of parallel power cables proposed in this application in one embodiment; Figure 4 This is a schematic diagram of the structure of the magnetic ring current equalizer in this application; Figure 5 Schematic diagram of simulation results of the impedance compensation effect of the magnetic ring current equalizer on the cable a1 in one embodiment of the present application; Figure 6 Schematic diagram of simulation results of the impedance compensation effect of the magnetic ring current equalizer on the cable a1 in another embodiment of the present application; Figure 7 Schematic diagram of simulation results of the impedance compensation effect of the magnetic ring current equalizer on the cable b1 in one embodiment of the present application; Figure 8 Schematic diagram of simulation results of the impedance compensation effect of the magnetic ring current equalizer on the cable b1 in another embodiment of the present application; Figure 9 Schematic diagram of simulation results of the impedance compensation effect of the magnetic ring current equalizer on the cable b1 in another embodiment of the present application; Figure 10 This is a structural schematic diagram of a parallel power cable current equalization optimization device based on a magnetic ring current equalizer proposed in an embodiment of the present application. DETAILED DESCRIPTION

[0025] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0026] In order to meet the surge in transmission capacity demand brought about by urbanization and the integration of new energy sources, traditional overhead lines are gradually being replaced by high-voltage cables. In order to improve the overall transmission capacity, multiple high-voltage cables of the same phase are usually used to form parallel power cables to meet the transmission capacity requirements. Figure 1 As shown, the parallel power cable includes two cables Cable1 and Cable2 connected in parallel, a circuit breaker QF, a current transformer CT, and a voltage transformer PT.

[0027] In some application scenarios, parallel power cables can be laid underground or on the seabed, significantly reducing space usage and minimizing the impact of electromagnetic radiation on the surrounding environment. However, in actual underground or submarine installations, parallel power cables are constrained by underground pipeline networks, geological conditions, or marine topography, resulting in non-straight installations. These include complex conditions such as bending (insufficient minimum bending radius), kinking (local deformation caused by construction errors), or interlacing (multiple cables crossing each other). These conditions disrupt idealized electromagnetic symmetry, leading to uneven load current distribution in parallel power cables due to impedance differences. Furthermore, electric field distortion in non-straight installation areas distorts the induced voltage values ​​of the metal sheaths in some locations, which can accelerate insulation aging and cause local overheating failures, seriously impacting the transmission safety of the parallel power cables.

[0028] According to an embodiment of the present application, an embodiment of a method for optimizing current equalization of parallel power cables based on a magnetic ring current equalizer is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0029] In this embodiment, a method for optimizing current sharing of parallel power cables based on a magnetic ring current equalizer is provided, which can be used in a high-voltage power transmission system including the above-mentioned parallel power cables. Figure 2 Flowchart of the current sharing optimization method for parallel power cables according to an embodiment of the present application. Figure 2 As shown, the process includes the following steps: Step S1 : simulating a three-dimensional finite element model of the parallel power cables, and determining a first simulated impedance of the parallel power cables according to a first simulation result of the three-dimensional finite element model.

[0030] Specifically, the embodiment of the present application establishes a three-dimensional finite element model based on finite element simulation software, which mainly includes the construction of the cable electro-magnetic coupling environment, as well as the 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, and the complex electromagnetic characteristics such as magnetic field distortion, current distribution, and sheath voltage of the parallel power cable in three-dimensional space are simulated by solving the Maxwell equations corresponding to the three-dimensional finite element model, thereby obtaining a first simulation result, and using the first simulation result to determine the first simulation impedance. Among them, the first simulation result represents the distribution of parameters such as current density and voltage of the parallel power cable, and thus can reflect the impedance of the parallel power cable.

[0031] Step S3: obtaining an equivalent circuit model of the parallel power cables, determining a theoretical impedance of the parallel power cables according to the equivalent circuit model, and determining a current impedance of the parallel power cables according to the theoretical impedance and the first simulated impedance.

[0032] Specifically, the present embodiment constructs an equivalent circuit model of parallel power cables in MATLAB based on cable parameters used in actual projects. In this equivalent circuit model, the electrical parameters of the parallel power cables are quantified into equivalent impedance parameters and equivalent inductive reactance parameters. These equivalent impedance parameters and equivalent inductive reactance parameters are then used to calculate the theoretical impedance. The theoretical impedance is then used to verify the first simulated impedance, reducing model simulation errors and ensuring accurate current impedance.

[0033] Step S5: obtain the electromagnetic field coupling model between the magnetic ring current equalizer and the parallel power cable, and determine several magnetic ring compensation parameters of the magnetic ring current equalizer. Simulate the electromagnetic field coupling model according to the several magnetic ring compensation parameters and the current impedance to determine the impedance compensation mapping relationship between each magnetic ring compensation parameter and the current impedance according to the second simulation result of the electromagnetic field coupling model.

[0034] Specifically, the embodiment of the present application utilizes the electromagnetic field coupling model between the magnetic ring current equalizer and the parallel power cable to determine the mapping relationship between each magnetic ring compensation parameter and the impedance compensation situation, thereby achieving accurate quantification between the parameter changes of the magnetic ring current equalizer and the current equalization optimization effect, providing an accurate quantitative basis for the subsequent current equalization optimization of the parallel power cables.

[0035] Step S7: determining an impedance compensation sensitivity matrix according to the impedance compensation mapping relationship, and setting the values ​​of the magnetic ring compensation parameters according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix to optimize the current sharing of the parallel power cables.

[0036] Specifically, the embodiment of the present application determines the impedance compensation sensitivity matrix based on the impedance compensation mapping relationship. The impedance compensation sensitivity matrix can characterize the quantitative relationship between the change in the parameters of the magnetic ring current equalizer and the degree of improvement in the bias flow, thereby dynamically adjusting the magnetic ring compensation parameters of the magnetic ring current equalizer using the impedance compensation sensitivity matrix to improve the adjustment efficiency of the magnetic ring compensation parameters.

[0037] Therefore, the parallel power cable current sharing optimization method provided in this embodiment determines the current impedance through three-dimensional finite element model simulation and equivalent circuit model calculation, thereby improving the accuracy of the impedance analysis of the parallel power cable. On the premise of accurately determining the current impedance, by establishing an electromagnetic field coupling model and determining the impedance compensation mapping relationship between the magnetic ring compensation parameters and the current impedance, the influence of the change of the magnetic ring compensation parameters of the magnetic ring current equalizer on the impedance compensation and the degree of improvement of the bias current is accurately quantified. Therefore, 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, thereby realizing the current sharing optimization of the parallel power cables for complex working conditions, greatly improving the uneven current distribution of the parallel power cables, improving the reliability of the parallel power cables, and facilitating the realization of power transmission safety.

[0038] In some embodiments of the present application, the process of constructing the three-dimensional finite element model includes: 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 model, conductivity conduction model and dielectric model are added during the field construction process.

[0039] The above field model is then set up according to the geometric parameters of the parallel power cables. Specifically, a specific model of the parallel power cables is built from the aspects of cable geometry, spatial distribution, and position distribution between the parallel cables of each phase. Based on the material parameters of common cables in actual engineering, reasonable material parameters are set for the busbar, cable conductor, insulation, metal sheath and outer sheath in the model. Finally, a reasonable soil resistivity is set, and a soil domain is created around the cable. The boundary is set as an infinite element domain to obtain a three-dimensional finite element model.

[0040] In an example of an embodiment of the present application, taking the 64 / 110YJLW02 model parallel power cable as an example, its relevant parameters are shown in Table 1, and then the following is constructed: Figure 3 The three-dimensional finite element model shown includes six cables a1, a2, b1, b2, c1 and c2.

[0041] Table 1 Furthermore, the geometric parameters of the parallel power cables 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 according to the setting result.

[0042] In some embodiments of the present application, the above step S1 further includes the following steps: Step S11 : applying a power frequency three-phase voltage excitation at the cable busbar interface to obtain a first simulation result of the three-dimensional finite element model in response to the power frequency three-phase voltage excitation.

[0043] Specifically, the embodiment of the present application simulates the operation of a three-dimensional finite element model under the action of power frequency three-phase voltage excitation to adapt to the actual operating conditions of parallel power cables. During the simulation process, the above-mentioned first simulation result can be displayed through a heat map, cloud map, etc., which can reflect the distribution of current density and voltage of the three-dimensional finite element model in response to the power frequency three-phase voltage excitation. That is, the first simulation result represents the bias current of the three-dimensional finite element model in response to the power frequency three-phase voltage excitation.

[0044] Step S12: determining impedance calculation parameters according to the first simulation result, and determining a first simulation impedance based on the impedance calculation parameters.

[0045] Specifically, the embodiment of the present application determines the bias current condition based on the first simulation result, and uses a probe to extract impedance calculation parameters related to the bias current condition, 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. The embodiment of the present application can use a probe to extract impedance calculation parameters such as open-circuit voltage, short-circuit voltage, and line current for lines with bias current, thereby obtaining the first simulated impedance.

[0046] It should be noted that, in the embodiment of the present application, the above-mentioned first simulated impedance is an impedance matrix including the simulated self-impedance and simulated mutual impedance between each cable. Taking the six cable conductors a1, a2, b1, b2, c1 and c2 as an example, the first simulated impedance is shown in Table 2.

[0047] Table 2 In the embodiment of the present application, an industrial frequency three-phase voltage excitation is applied at the cable busbar interface in a three-dimensional finite element model to simulate the excitation conditions of the parallel power cables in actual operation, so that the first simulation result obtained is more consistent with the actual working conditions, thereby making the impedance calculation parameters and the first simulation impedance determined based on the first simulation result more accurate, providing an accurate data basis for the subsequent setting of the magnetic ring compensation parameters to achieve current sharing optimization.

[0048] In some embodiments of the present application, the above step S3 further includes the following steps: In step S31 , several cables of the parallel power cables are equivalent to several branches as an equivalent circuit model.

[0049] Specifically, taking the parallel power cables including the above-mentioned six cables a1, a2, b1, b2, c1 and c2 as an example, the cable cores of cables a1, a2, b1, b2, c1 and c2 are equivalent to six branches, and the metal sheaths na1, na2, nb1, nb2, nc1 and nc2 corresponding to each cable are equivalent to six branches. Each branch can be equivalent to electrical components such as resistance, capacitance, inductance with corresponding parameters based on the physical properties of the cable core / metal sheath materials themselves and the mutual coupling between cables, so that these branches are constructed as equivalent circuit models based on MATLAB.

[0050] Step S32: determining AC resistance parameters of the plurality of branches, so as to determine equivalent self-impedances of the plurality of branches according to the AC resistance parameters.

[0051] Specifically, the cable core and the corresponding metal sheath are equivalent to the superposition of AC resistance and self-inductance. Therefore, the AC resistance parameters of each branch are shown in the following formula (1): Where, is the AC resistance parameter of the branch, is the DC resistance parameter of the branch, Indicates the cable type coefficient, where the y value corresponding to the single-core, double-core, and three-core cable types is 1, and the y value corresponding to the pipeline cable type is 1.5. is the skin effect coefficient, is the proximity effect coefficient.

[0052] Furthermore, the DC resistance parameter The calculation formula is shown in the following formula (2): Where, is the conductor resistivity, in Ω•m, is the nominal cross-sectional area of ​​the conductor, in m 2 , The resistance temperature coefficient corresponding to 20℃, unit is ℃ -1 , is the conductor temperature in °C.

[0053] Skin effect coefficient The calculation formula is shown in the following formula (3): Where, the calculation formula of z is shown in the following formula (4): Where, is the cable frequency in Hz, is the first coefficient of the conductor type, where the conductor type of the cable is copper core The value is 1.

[0054] Proximity effect coefficient The calculation formula is shown in the following formula (5): Where, The second coefficient of the conductor type, where the conductor type of the cable is copper core, aluminum core, sector or ring The value is 0.8, is the radius of the conductor or shielding layer, in m, is the conductor spacing, in m.

[0055] Based on the above formulas (1) to (5), the AC resistance parameters of several branches can be calculated , further, the equivalent self-impedance of the i-th branch is calculated based on the following formula (6): for: Where, is the AC resistance per unit length, which is the same as the above Related, the unit is Ω, is the soil resistivity, in Ω•m, It is the equivalent diameter of conductor / shield, in m.

[0056] Step S33: determining the equivalent mutual impedance between the branches, and determining the theoretical impedance according to the equivalent self-impedance and the equivalent mutual impedance.

[0057] Specifically, the equivalent self-impedance between the i-th branch and the j-th branch is calculated based on the following formula (7): for: Where, is the distance between the conductor / shield of the i-th branch and the j-th branch.

[0058] Then according to 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 of the six cables a1, a2, b1, b2, c1, and c2 is shown in Table 3.

[0059] Table 3 Step S34, determining a calibration error between the theoretical impedance and the first simulated impedance, and when the calibration error satisfies a preset condition, performing a weighted average calculation on the theoretical impedance and the first simulated impedance, and determining the current impedance based on the calculation result.

[0060] Specifically, the two impedance matrices shown in Tables 2 and 3 are compared. If the calibration error determined by the comparison is less than a preset value, the calibration error is determined to meet the preset conditions, and the current impedance is calculated by weighted mean calculation. Preferably, if the calibration error is less than 5%, the calibration error meets the preset conditions; otherwise, the three-dimensional finite element model and equivalent circuit model need to be modified.

[0061] For example, the core self-inductance of cable a1 in the first simulated impedance was 0.0203H / km, while the core self-inductance of cable a1 in the theoretical impedance was 0.0223H / km, resulting in a calibration error of 8.97%. Subsequently, combining the theoretical basis for formula derivation with verification of various material and environmental parameters during the simulation, the cause was determined to be insufficiently large calculation domains in the Comsol simulation, resulting in the ineffective simulation of the equivalent Carson depth in the formula. The calculation domain size was then modified in the 3D finite element model, with the soil domain boundary set to 1300m. The core self-inductance of cable a1 was re-extracted to 0.0224H / km, reducing the calibration error to 0.4%.

[0062] In addition, the embodiment of the present application can also obtain the loop matrix equation of the equivalent circuit model based on Kirchhoff's voltage law as shown in the following formula (8): Formula (8); Where, It represents the mutual impedance between metal sheath na1 and metal sheath na2. The mutual impedance between other metal sheaths can be deduced by analogy. It represents the mutual impedance between the cable conductor a1 and the metal sheath na2. The mutual impedance between other conductors and the metal sheath is similar. It represents the mutual impedance between cable conductor a1 and cable conductor c2. The mutual impedance between other conductors is similar. to It represents the sheath current in the six branches of the metal sheath na1 to nc2. to It represents the current flowing through the six branches of the cable conductors a1 to c2. 、 and Indicates the three-phase voltage applied to both ends of the parallel cable.

[0063] The above current to The simulation current flowing through each cable obtained by simulating the 3D finite element model is verified to ensure the accuracy of the 3D finite element model and the equivalent circuit model, and can be verified by to Analyze the current deviation of parallel power cables.

[0064] The embodiment of the present application equates several cables to several branches to obtain an equivalent circuit model, and then solves and calculates the equivalent circuit model to obtain a theoretical impedance, so as to facilitate the subsequent verification of the first simulated impedance and the theoretical impedance, thereby improving the accuracy of the impedance analysis of the parallel power cable. In addition, the embodiment of the present application 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, and determines that the model is accurate when the verification error meets the preset conditions. At the same time, the current impedance is determined by a weighted average calculation method, further improving the accuracy of the impedance analysis of the parallel power cable, and providing an accurate data basis for the subsequent precise quantification of the impact of changes in the magnetic ring compensation parameters of the magnetic ring current equalizer on the impedance compensation and the degree of bias current improvement.

[0065] In some embodiments of the present application, the above step S5 further includes the following steps: Step S51: adjusting the three-dimensional finite element model according to the current impedance.

[0066] Specifically, relevant parameters in the three-dimensional finite element model are set according to the current impedance determined in step S34.

[0067] Step S52: constructing a magnetic ring current equalizer model based on finite element simulation software, and adding the magnetic ring current equalizer model to the adjusted three-dimensional finite element model to obtain an electromagnetic field coupling model.

[0068] Specifically, if Figure 4 As shown, the magnetic ring current equalizer includes magnets 101, 102, and 103, as well as a fastener 2, an adjustment device 3, and a housing 5. When the magnets 101, 102, and 103 wrap around the cable 4, their high magnetic permeability significantly increases the inductive reactance of the cable 4. By adjusting the air gap width A, the magnetic circuit reluctance is changed, thereby dynamically adjusting the inductance value. The magnet is composed of multiple sector-shaped magnetic blocks 101, 102, and 103 assembled into a circular ring that surrounds the outside of the cable 4. The magnetic material is high-permeability silicon steel sheet or ferrite. The fastener 2 is used to fix adjacent magnetic blocks without an air gap. The adjustment device 3 includes a fixing member 31 and a regulator 32, which are formed into a threaded or snap-fit ​​structure. The fixing member 31 is mounted on the housing 5 of the magnetic block with an air gap. The regulator 32 is movably connected to the fixing member 31. By adjusting the air gap width A between adjacent magnetic blocks, the inductive reactance is changed, thereby achieving impedance compensation. In addition, a liquid crystal display as a current monitoring device is installed on the cable near the magnet to display the cable current size.

[0069] The embodiment of the present application uses finite element simulation software to construct a magnetic ring current equalizer model, wherein, according to Ampere's law and the law of conservation of current, appropriate magnetization model, conductivity conduction model and dielectric model are added in the field construction process. Figure 4The structure shown is used to build a geometric model of the magnetic ring current equalizer, and set the size parameters suitable for the built cable model and the material parameters that meet the actual engineering requirements.

[0070] The constructed magnetic ring current equalizer 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 equalizer and the parallel power cable.

[0071] Step S53: using the control variable method to change the values ​​of several magnetic ring compensation parameters, and simulating the electromagnetic field coupling model when the magnetic ring compensation parameters are at different values, so as to determine the second simulation impedance of the parallel power cable according to the second simulation result.

[0072] Specifically, the magnetic ring compensation parameter includes at least one of a magnetic ring thickness, a magnetic ring height, and a magnetic ring air gap opening angle of the magnetic ring current equalizer.

[0073] Finite element simulation software was used to simulate the effect of changes in the magnetic ring compensation parameters on impedance compensation. For example, the magnetic ring thickness, magnetic ring air gap opening angle, and material parameters were kept constant during the simulation. Specifically, the magnetic ring inner diameter was set to 0.0363m, the magnetic ring outer diameter was set to 0.05m, and the magnetic ring air gap opening angle was set to 20°. The magnetic ring height was then changed to 0.01m, 0.015m, and 0.02m, respectively. Second simulation results and corresponding second simulated impedances were recorded. The specific process can be found in step S12 above. Similarly, a probe was used to extract the relevant impedance calculation parameters from the second simulation results, and the second simulated impedance was calculated using the open-circuit-short-circuit method.

[0074] For other magnetic ring compensation parameters, similarly, the value of one of the magnetic ring compensation parameters is changed while keeping the other magnetic ring compensation parameters unchanged, thereby determining the second simulation impedance through the second simulation result.

[0075] Step S54: determining impedance compensation amounts corresponding to magnetic ring compensation parameters with different values ​​according to the difference between the second simulated impedance and the current impedance.

[0076] Specifically, the difference between the second simulated impedance and the current impedance represents the impedance compensation effect of the magnetic ring current equalizer on the parallel power cables. It should be noted that in some embodiments of the present application, the impedance compensation amount is the equivalent compensation inductance value generated by the magnetic ring current equalizer.

[0077] Taking the impedance compensation effect of the magnetic ring current equalizer on cable a1 as an example, the second simulation result is as follows: Figure 5 and Figure 6 As shown by Figure 5It can be seen that the height of the magnetic ring is positively correlated with the compensation inductance, and the height of the magnetic ring mainly affects the self-inductance value of the corresponding cable, while the compensation for the mutual inductance value can be ignored. Figure 6 It can be seen that when only cable a1 is added with a magnetic ring current equalizer, its effect on the self-inductance values ​​of other surrounding phase cables is also very small and can basically be 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 acted by the magnetic ring current equalizer increases in a positive correlation.

[0078] 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, Figure 7 The figure shows the effect of the magnetic ring height on the impedance compensation. Figure 8 The figure shows the effect of the thickness of the magnetic ring on the impedance compensation. Figure 9 The figure shows the effect of the ring air gap opening angle on impedance compensation.

[0079] 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 equalizer to the cable a2 increases in a positive correlation. Figure 8 It can be seen that as the thickness of the magnetic ring increases, the impedance compensation amount of the magnetic ring current equalizer to the cable a2 increases in a positive correlation. Figure 9 It can be seen that the impedance compensation provided by the magnetic ring current equalizer for cable a2 increases in a positive correlation with the increase in the magnetic ring air gap opening angle. Furthermore, the magnetic ring current equalizer has no significant effect on the mutual inductance between cable a2 and other phase cables. In other words, the impedance compensation provided by the magnetic ring current equalizer for parallel power cables is primarily reflected in self-inductance compensation, and its impact on mutual inductance is negligible.

[0080] Step S55 , fitting the magnetic ring compensation parameters and the impedance compensation amount, so as to determine the mapping relationship between each magnetic ring compensation parameter and the impedance compensation for the current impedance according to the fitting result.

[0081] Specifically, by fitting the magnetic ring compensation parameters and the impedance compensation amount, the influence of the change of the magnetic ring compensation parameters on the impedance compensation can be quantified. Therefore, based on the above impedance compensation mapping relationship, the impedance compensation amount corresponding to different values ​​of the magnetic ring compensation parameters can be determined.

[0082] The embodiment of the present application uses the control 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 the magnetic ring compensation parameter and the impedance compensation value, so as to accurately quantify the impact of the change of the magnetic ring compensation parameter of the magnetic ring current equalizer on the impedance compensation, so that 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 conducive to accurately setting the magnetic ring compensation parameters to achieve current sharing optimization of the parallel power cables.

[0083] In some embodiments of the present application, the above step S7 further includes the following steps: Step S71 : determining the influence of each magnetic ring compensation parameter on the impedance compensation of the parallel power cables according to the impedance compensation mapping relationship.

[0084] Specifically, the impedance compensation mapping relationship can be a fitted relationship between the magnetic ring compensation parameter and the impedance compensation amount, and the fitted relationship is a positive correlation function. Therefore, the degree of impedance compensation influence can be determined based on the slope of the fitted relationship. The larger the slope of the fitted relationship, the greater the impact of changes in the magnetic ring compensation parameter on the impedance compensation amount, that is, the more sensitive the impedance compensation amount is to changes in the magnetic ring compensation parameter.

[0085] The above impedance compensation mapping relationship can also be the impedance compensation amounts corresponding to the magnetic ring compensation parameters that change in preset step amounts. Therefore, the greater the change in the impedance compensation amount, the greater the impact of the change in the magnetic ring compensation parameter on the impedance compensation amount.

[0086] Step S72: determining the compensation sensitivity level according to the impedance compensation influence degree.

[0087] Specifically, the compensation sensitivity level is set according to the degree of influence of the impedance compensation. The higher the degree of influence of the impedance compensation, the higher the level of the compensation sensitivity level.

[0088] Step S73: generating an impedance compensation sensitivity matrix according to the compensation sensitivity classification.

[0089] Specifically, the impedance compensation sensitivity matrix is ​​used to characterize the 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 greater impedance compensation influence are adjusted first.

[0090] Step S74: determine the target flow rate and obtain the target impedance corresponding to the target flow rate.

[0091] For example, the adjusted 3D finite element model is simulated to obtain the simulated current flowing through each cable corresponding to the current impedance. Based on the simulated current, the current imbalance is determined to be 15%. The target current balance is determined to be 5%, and the target impedance corresponding to the target current balance of 5% is determined.

[0092] Step S75: determining the priority of the magnetic ring compensation parameters according to the impedance compensation sensitivity matrix.

[0093] Specifically, if a small change in a magnetic ring compensation parameter in the impedance compensation sensitivity matrix can cause a large change in impedance compensation, significantly affecting the current sharing effect, then this magnetic ring compensation parameter will have a higher priority in the adjustment process. Conversely, if a parameter change has a smaller impact on impedance compensation and current sharing, it will have a lower priority.

[0094] When optimizing the 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 preferentially based on 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.

[0095] Step S76: determining a value scheme for the magnetic ring compensation parameter according to the target impedance, the current impedance, the impedance compensation mapping relationship, and the priority.

[0096] Specifically, the amount to be compensated is determined based on the difference between the target impedance and the current impedance, and then the adjustment order of each magnetic ring compensation parameter is determined according to the priority, with the magnetic ring height being adjusted first, followed by the magnetic ring thickness, and finally the magnetic ring air gap opening angle. Based on the impedance compensation mapping relationship, the value scheme of the 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.

[0097] For example, to reduce the current imbalance from 15% to 5%, finite element simulation parameter sweeps and numerical calculations determined that the required compensation for cable a2 is a self-inductance of 222.69 nH / m. Based on the impedance compensation mapping relationship obtained in previous simulations, a set of values ​​was determined: a magnetic ring height of 0.025 m, a magnetic ring thickness of 0.055 m, and a magnetic ring air gap angle of 10°.

[0098] Step S77: setting the values ​​of the magnetic ring compensation parameters according to the value scheme so that the current flowing through the parallel power cables meets the target current sharing degree.

[0099] Specifically, the above-mentioned value selection scheme is applied to the magnetic ring current equalizer corresponding to each phase cable to verify through simulation whether the current imbalance is reduced from 15% to 5%. If the target current equalization is not reached, the above-mentioned magnetic ring compensation parameters are continued to be adjusted until the target current equalization requirements are met.

[0100] The embodiment of the present application determines the degree of influence of each magnetic ring compensation parameter on the impedance compensation of the parallel power cables through the impedance compensation mapping relationship, and then generates an impedance compensation sensitivity matrix based on the impedance compensation influence degree, so as to use the impedance compensation sensitivity matrix to characterize the quantitative relationship of each magnetic ring compensation parameter on the current sharing improvement effect, which is conducive to improving the adjustment efficiency of the magnetic ring compensation parameters.

[0101] In addition, by determining the priority of the magnetic ring compensation parameters, the adjustment order of multiple magnetic ring compensation parameters is clarified, so that the values ​​of each magnetic ring compensation parameter are accurately set according to the priority order and based on the impedance compensation mapping relationship, so that the impedance of the parallel power cable is compensated from the current impedance to the target impedance. This not only further refines the dynamic control process of impedance compensation and improves the current sharing optimization efficiency, but also makes the value scheme of the magnetic ring compensation parameters more adaptable to actual complex working conditions, 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.

[0102] Accordingly, please refer to Figure 10 The present invention provides a parallel power cable current equalization optimization device based on a magnetic ring current equalizer, the device comprising: A simulated impedance determination module 810 is configured to simulate a three-dimensional finite element model of the parallel power cables and determine a first simulated impedance of the parallel power cables based on a first simulation result of the three-dimensional finite element model; a current impedance determination module 820 configured to obtain an equivalent circuit model of the parallel power cables, determine a theoretical impedance of the parallel power cables based on the equivalent circuit model, and determine a current impedance of the parallel power cables based on the theoretical impedance and a first simulated impedance; An impedance compensation mapping module 830 is configured to obtain an electromagnetic field coupling model between the magnetic ring current equalizer and the parallel power cable, determine a plurality of magnetic ring compensation parameters of the magnetic ring current equalizer, simulate the electromagnetic field coupling model based on the plurality of magnetic ring compensation parameters and the current impedance, and determine an impedance compensation mapping relationship between each magnetic ring compensation parameter and the current impedance based on a second simulation result of the electromagnetic field coupling model; The current sharing optimization module 840 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 to optimize the current sharing of the parallel power cables.

[0103] In some embodiments of the present application, the simulated impedance determination module 810 further includes: The first simulation unit 811 is used to apply power frequency three-phase voltage excitation at the cable bus interface to obtain a first simulation result of the three-dimensional finite element model in response to the power frequency three-phase voltage excitation.

[0104] The first calculation unit 812 is configured to determine impedance calculation parameters according to the first simulation result, and determine a first simulated impedance based on the impedance calculation parameters.

[0105] In some embodiments of the present application, the current impedance determination module 820 further includes: The equivalent circuit modeling unit 821 is used to convert several cables of the parallel power cables into several branches as an equivalent circuit model.

[0106] The second calculation unit 822 is configured to determine AC resistance parameters of the plurality of branches, so as to determine equivalent self-impedances of the plurality of branches according to the AC resistance parameters.

[0107] The third calculation unit 823 is used to determine the equivalent mutual impedance between the branches, and determine the theoretical impedance according to the equivalent self-impedance and the equivalent mutual impedance.

[0108] The verification unit 824 is used to determine a verification error between the theoretical impedance and the first simulated impedance. When the verification error meets a preset condition, a weighted average calculation is performed on the theoretical impedance and the first simulated impedance, and the current impedance is determined based on the calculation result.

[0109] In some embodiments of the present application, the impedance compensation mapping module 830 further includes: The coupling model modeling unit 831 is used to adjust the three-dimensional finite element model according to the current impedance, build a magnetic ring current equalizer model based on the 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.

[0110] a second simulation unit 832 configured to change the values ​​of a plurality of magnetic ring compensation parameters using a control variable method, and simulate the electromagnetic field coupling model when the magnetic ring compensation parameters are at different values, so as to determine a second simulated impedance of the parallel power cables according to the second simulation results; The mapping determination unit 833 is used to determine the impedance compensation amount corresponding to the magnetic ring compensation parameters with different values ​​according to the difference between the second simulated impedance and the current impedance, and to fit the magnetic ring compensation parameters and the impedance compensation amount to determine the impedance compensation mapping relationship between each magnetic ring compensation parameter and the current impedance according to the fitting result.

[0111] In some embodiments of the present application, the current sharing optimization module 840 further includes: The sensitivity determination unit 841 is used to determine the influence of each magnetic ring compensation parameter on the impedance compensation of the parallel power cables according to the impedance compensation mapping relationship, determine the compensation sensitivity classification according to the impedance compensation influence degree, and generate an impedance compensation sensitivity matrix according to the compensation sensitivity classification.

[0112] The value-taking unit 842 is used to determine the target average flow and obtain the target impedance corresponding to the target average flow, determine the priority of the magnetic ring compensation parameters according to the impedance compensation sensitivity matrix, and determine the value-taking scheme of the magnetic ring compensation parameters according to the target impedance, current impedance, impedance compensation mapping relationship and priority.

[0113] The optimization unit 843 is used to set the value of the magnetic ring compensation parameter according to the value scheme so that the current flowing through the parallel power cables meets the target current sharing degree.

[0114] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0115] The parallel power cable current sharing optimization device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0116] A computer device provided in an embodiment of the present application comprises: one or more processors, a memory, and an interface for connecting various components, including a high-speed interface and a low-speed interface. Various components are connected to each other using different buses for communication and can be installed on a common mainboard or installed in other ways as needed. The processor can process instructions executed in the computer device, including instructions stored in or on the memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to an interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system).

[0117] The processor may be a central processing unit, a network processor, or a combination thereof. The processor may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0118] The memory stores instructions that can be executed by at least one processor, so that the at least one processor executes the method shown in the above embodiment.

[0119] The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created based on the use of the computer device, etc. In addition, the memory may include a high-speed random access memory and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory may optionally include a memory remotely located relative to the processor, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0120] The memory may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0121] For the convenience of description, the above devices are described as being divided into various units according to their functions. Of course, when implementing this application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0122] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0123] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0124] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0125] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0126] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0127] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

[0128] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A method for optimizing current sharing of parallel power cables based on a magnetic ring current equalizer, characterized in that: The method comprises: Simulating a three-dimensional finite element model of the parallel power cables, and determining a first simulated impedance of the parallel power cables according to a first simulation result of the three-dimensional finite element model; Obtaining an equivalent circuit model of the parallel power cables, determining a theoretical impedance of the parallel power cables according to the equivalent circuit model, and determining a current impedance of the parallel power cables according to the theoretical impedance and the first simulated impedance; Obtaining an electromagnetic field coupling model between the magnetic ring current equalizer and the parallel power cable, and determining a plurality of magnetic ring compensation parameters of the magnetic ring current equalizer, simulating the electromagnetic field coupling model according to the plurality of magnetic ring compensation parameters and the current impedance, so as to determine an impedance compensation mapping relationship between each of the magnetic ring compensation parameters and the current impedance according to a second simulation result of the electromagnetic field coupling model; An impedance compensation sensitivity matrix is ​​determined according to the impedance compensation mapping relationship, and values ​​of the magnetic ring compensation parameters are set according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix to optimize current sharing of the parallel power cables.

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

3. The method according to claim 1, characterized in that The obtaining of the equivalent circuit model of the parallel power cables and determining the theoretical impedance of the parallel power cables according to the equivalent circuit model includes: Equivalently treating the plurality of cables of the parallel power cables as a plurality of branches as the equivalent circuit model; determining AC resistance parameters of the plurality of branches, so as to determine equivalent self-impedances of the plurality of branches according to the AC resistance parameters; An equivalent mutual impedance between the branches is determined, and the theoretical impedance is determined based on the equivalent self-impedance and the equivalent mutual impedance.

4. The method according to claim 1, wherein The determining the current impedance of the parallel power cables according to the theoretical impedance and the first simulated impedance includes: determining a calibration error between the theoretical impedance and the first simulated impedance; When the calibration error satisfies a preset condition, a weighted average calculation is performed on the theoretical impedance and the first simulated impedance, and the current impedance is determined according to the calculation result.

5. The method according to claim 1, wherein The obtaining of the electromagnetic field coupling model between the magnetic ring current equalizer and the parallel power cable includes: adjusting the three-dimensional finite element model according to 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 simulating the electromagnetic field coupling model according to the plurality of magnetic ring compensation parameters and the current impedance to determine an impedance compensation mapping relationship between each magnetic ring compensation parameter and the current impedance according to a second simulation result of the electromagnetic field coupling model includes: using a control variable method to change the values ​​of several magnetic ring compensation parameters, and simulating the electromagnetic field coupling model when the magnetic ring compensation parameters are at different values, so as to determine a second simulated impedance of the parallel power cable according to the second simulation result; determining impedance compensation amounts corresponding to different values ​​of the magnetic ring compensation parameters according to a difference between the second simulated impedance and the current impedance; The magnetic ring compensation parameters and the impedance compensation amount are fitted to determine a mapping relationship between each of the magnetic ring compensation parameters and the impedance compensation for the current impedance according to a fitting result.

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

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

9. The method according to claim 1, characterized in that The setting of the value of the magnetic ring compensation parameter according to the impedance compensation mapping relationship and the impedance compensation sensitivity matrix to optimize the current sharing of the parallel power cables includes: Determining a target flow rate and obtaining a target impedance corresponding to the target flow rate; Determining the priority of the magnetic ring compensation parameters according to the impedance compensation sensitivity matrix; Determining a value scheme for the magnetic ring compensation parameter according to the target impedance, the current impedance, the impedance compensation mapping relationship, and the priority; The value of the magnetic ring compensation parameter is set according to the value scheme so that the current flowing through the parallel power cables meets the target current sharing degree.

10. A parallel power cable current equalization optimization device based on a magnetic ring current equalizer, characterized in that: The device comprises: a simulated impedance determination module, configured to simulate a three-dimensional finite element model of the parallel power cables and determine a first simulated impedance of the parallel power cables according to a first simulation result of the three-dimensional finite element model; a current impedance determination module, configured to obtain an equivalent circuit model of the parallel power cables, determine a theoretical impedance of the parallel power cables according to the equivalent circuit model, and determine a current impedance of the parallel power cables according to the theoretical impedance and the first simulated impedance; an impedance compensation mapping module, configured to obtain an electromagnetic field coupling model between the magnetic ring current equalizer and the parallel power cable, determine a plurality of magnetic ring compensation parameters of the magnetic ring current equalizer, simulate the electromagnetic field coupling model according to the plurality of magnetic ring compensation parameters and the current impedance, and determine an impedance compensation mapping relationship between each of the magnetic ring compensation parameters and the current impedance according to a second simulation result of the electromagnetic field coupling model; A current sharing optimization module is used to determine an 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 to optimize the current sharing of the parallel power cables.

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