Simulation modeling method and device for long-distance superconducting direct-current cable and terminal equipment

Abstract

The invention discloses a simulation modeling method and device for a long-distance superconducting direct-current cable and terminal equipment, and the method comprises the steps: carrying out the simulation modeling of the superconducting direct-current cable, and obtaining a superconducting direct-current cable simulation model; building a distributed equivalent circuit model of the long-distance superconducting direct-current cable based on the superconducting direct-current cable simulation model; constructing a distributed model of the superconducting direct current cable according to the distributed equivalent circuit model; performing analogue simulation on the distributed model, and giving an initial value to the quench resistance of a corresponding basic unit equivalent circuit when the superconducting direct current cable is quenched in the basic unit equivalent circuit to obtain a to-be-processed quench resistance; according to each quench resistor to be processed and a preset relation curve, simulation iteration is carried out to determine a true value of the quench resistor of each basic unit equivalent circuit; and feeding back the true value of the quench resistance of the equivalent circuit of each basic unit to operation and maintenance personnel of the superconducting direct current cable, so that the operation and maintenance personnel optimize the superconducting direct current cable according to the true value of the quench resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting DC cables, and in particular to a simulation modeling method, device and terminal device for long-distance superconducting DC cables. Background Technique

[0002] Superconducting power transmission technology has significant advantages such as large transmission capacity, low loss, and compact structure, and is one of the hotspots in the research of power transmission technology recently. The research on superconducting power transmission technology mainly focuses on studying the operating characteristics and fault mechanisms of superconducting DC cables when connected to long-distance DC power transmission systems. It is particularly important to establish a superconducting DC cable model considering the quench characteristics and distribution characteristics to analyze the quench characteristics of superconducting DC cables. Establishing a superconducting DC cable model and conducting cable quench analysis are of great significance for the design and operation management of superconducting DC cables. However, the current superconducting cable simulation modeling method regards the cable as a whole for quench analysis, and it is difficult to conduct quench analysis on the whole cable when connected to a long-distance DC power transmission system. Summary of the Invention

[0003] Embodiments of the present invention provide a simulation modeling method, device and terminal device for long-distance superconducting DC cables, which can improve the efficiency of simulation modeling and quench analysis of long-distance superconducting DC cables.

[0004] An embodiment of the present invention provides a simulation modeling method, device and terminal device for long-distance superconducting DC cables, including:

[0005] Conduct simulation modeling on a superconducting DC cable to obtain a superconducting DC cable simulation model; wherein, the superconducting DC cable simulation model includes: a superconducting layer and a copper skeleton layer;

[0006] Based on the superconducting DC cable simulation model, construct a distributed equivalent circuit model of the long-distance superconducting DC cable; wherein, the distributed equivalent circuit model includes several basic unit equivalent circuits, each basic unit equivalent circuit corresponds to a superconducting DC cable section, and each basic unit equivalent circuit includes an equivalent resistance corresponding to the superconducting DC cable section, and the equivalent resistance is composed of the parallel connection of the superconducting layer resistance and the copper skeleton layer resistance;

[0007] Construct a distributed model of the superconducting DC cable according to the distributed equivalent circuit model;

[0008] Conduct simulation on the distributed model. When a superconducting DC cable quench occurs in a basic unit equivalent circuit, assign an initial value to the quench resistance of the corresponding basic unit equivalent circuit to obtain a to-be-processed quench resistance; wherein, the quench resistance is the superconducting layer resistance during quench;

[0009] Determine the true value of the quench resistance of each basic unit equivalent circuit through simulation iteration based on each quench resistance to be processed and a preset relationship curve; wherein, the preset relationship curve is the relationship curve between the quench resistance and the quench heat.

[0010] Feed back the true value of the quench resistance of each basic unit equivalent circuit to the superconducting DC cable operation and maintenance personnel, so that the operation and maintenance personnel can optimize the superconducting DC cable according to the true value of the quench resistance.

[0011] Further, the construction of the distributed equivalent circuit model of the long-distance superconducting DC cable based on the superconducting DC cable simulation model includes:

[0012] Divide the superconducting DC cable simulation model into several superconducting DC cable simulation sub-models based on a preset simulation accuracy; each superconducting DC cable simulation sub-model corresponds to a superconducting DC cable section.

[0013] Establish a corresponding basic unit equivalent circuit for each superconducting DC cable simulation sub-model.

[0014] Construct a distributed equivalent circuit model of the long-distance superconducting DC cable according to each basic unit equivalent circuit.

[0015] Further, the superconducting DC cable simulation model also includes: liquid nitrogen, electrical insulation layer and thermal insulation layer.

[0016] The superconducting layer, electrical insulation layer, liquid nitrogen and thermal insulation layer are sequentially wrapped outside the copper skeleton layer.

[0017] Further, each basic unit equivalent circuit also includes: resistance and capacitance to ground.

[0018] The equivalent resistance of the superconducting DC cable is in series with the reactance, and the capacitance to ground is connected in parallel on both sides. Further, after constructing the distributed equivalent circuit model of the long-distance superconducting DC cable based on the superconducting DC cable simulation model, it also includes:

[0019] For each basic unit equivalent circuit, obtain the thermal parameters of the superconducting DC cable simulation model corresponding to each basic unit equivalent circuit; wherein, the thermal parameters include: the equivalent resistance of the superconducting DC cable, the heat absorbed by the superconducting tape, the heat capacity of each component of the superconducting tape, the liquid nitrogen coverage area and the cable temperature.

[0020] Construct a thermal model of the current basic unit equivalent circuit according to the thermal parameters.

[0021] The construction of the distributed model of the superconducting DC cable according to the distributed equivalent circuit model includes:

[0022] Construct a distributed model of the superconducting DC cable according to each basic unit equivalent circuit and the thermal model corresponding to each basic unit equivalent circuit.

[0023] Further, simulating the distributed model, when a superconducting DC cable quench occurs in an equivalent circuit of a basic unit, assigning an initial value to the quench resistance of the equivalent circuit of the corresponding basic unit to obtain a quench resistance to be processed, including:

[0024] Setting simulation parameters of the distributed model of the superconducting DC cable; wherein, the simulation parameters include: critical current;

[0025] Performing simulation on the distributed model based on the set simulation parameters;

[0026] When the real-time current of any equivalent circuit of a basic unit exceeds the critical current, the superconducting DC cable in the corresponding section of the current basic unit equivalent circuit quenches;

[0027] Assigning an initial value to the quench resistance of the current basic unit equivalent circuit to obtain a quench resistance to be processed.

[0028] Further, after obtaining the quench resistance to be processed, it further includes:

[0029] Obtaining the length of the superconducting DC cable and the cross-sectional area of the copper skeleton layer in the corresponding section of the current basic unit equivalent circuit;

[0030] Determining the quench temperature according to the thermal model of the current basic unit equivalent circuit;

[0031] Calculating the resistance of the copper skeleton layer during quench according to the quench temperature, the length of the superconducting DC cable in the corresponding section of the current basic unit equivalent circuit, and the cross-sectional area of the copper skeleton layer.

[0032] Further, the simulating and iterating according to each quench resistance to be processed and a preset relationship curve to determine the true value of the quench resistance of each basic unit equivalent circuit includes:

[0033] For each quench resistance to be processed, performing a quench resistance value update operation until the iteration error is less than a preset difference threshold, and taking the quench resistance value to be processed in the current iteration as the true value of the quench resistance;

[0034] Wherein, the quench resistance value update operation includes:

[0035] According to the basic unit equivalent circuit including the quench resistance to be processed, obtaining the current curve of the quench resistance to be processed in the current iteration;

[0036] Determining the quench heat curve according to the thermal model corresponding to the basic unit equivalent circuit including the quench resistance to be processed;

[0037] Determining the quench resistance value to be processed in the next iteration according to the quench heat curve and the preset relationship curve;

[0038] Substitute the quench resistance value to be processed in the next iteration into the equivalent circuit of the current basic unit to obtain the current curve corresponding to the quench resistance value to be processed in the next iteration;

[0039] Calculate the iteration error according to the current curve corresponding to the quench resistance value to be processed in the current iteration and the current curve corresponding to the quench resistance value to be processed in the next iteration.

[0040] Based on the above method embodiment, the present invention correspondingly provides a device embodiment;

[0041] An embodiment of the present invention correspondingly provides a simulation modeling device for a long-distance superconducting DC cable, including: a distributed model modeling module, a simulation and simulation module, and a guidance and optimization module;

[0042] The distributed model modeling module is used to perform simulation modeling on the superconducting DC cable to obtain a superconducting DC cable simulation model; wherein, the superconducting DC cable simulation model includes: a superconducting layer and a copper skeleton layer; based on the superconducting DC cable simulation model, a distributed equivalent circuit model of the long-distance superconducting DC cable is constructed; wherein, the distributed equivalent circuit model includes a plurality of basic unit equivalent circuits, each basic unit equivalent circuit corresponds to a superconducting DC cable section, and each basic unit equivalent circuit includes an equivalent resistance corresponding to the superconducting DC cable section, and the equivalent resistance is composed of the parallel connection of the superconducting layer resistance and the copper skeleton layer resistance; a distributed model of the superconducting DC cable is constructed according to the distributed equivalent circuit model;

[0043] The simulation and simulation module is used to perform simulation and simulation on the distributed model. When a superconducting DC cable quench occurs in a basic unit equivalent circuit, an initial value is given to the quench resistance of the corresponding basic unit equivalent circuit to obtain the quench resistance to be processed; wherein, the quench resistance is the superconducting layer resistance during quench; the true values of the quench resistances of each basic unit are determined by simulation iteration according to each quench resistance to be processed and a preset relationship curve; wherein, the preset relationship curve is the relationship curve between the quench resistance and the quench heat;

[0044] The guidance and optimization module is used to feedback the true values of the quench resistances of each basic unit equivalent circuit to the superconducting DC cable operation and maintenance personnel, so that the operation and maintenance personnel can optimize the superconducting DC cable according to the true values of the quench resistances.

[0045] Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the above-mentioned simulation modeling method for a long-distance superconducting DC cable in the embodiment of the present invention is implemented.

[0046] By implementing the present invention, the following beneficial effects are achieved:

[0047] The present invention provides a simulation modeling method, device and terminal device for a long-distance superconducting DC cable. After simulating and modeling the superconducting DC cable, the superconducting DC cable is segmented based on the superconducting DC cable, and an equivalent circuit of a basic unit of each segment of the superconducting DC cable is constructed, so as to obtain a distributed equivalent circuit model including the equivalent circuits of basic units corresponding to several cable segments. Then, a distributed model of the superconducting DC cable is constructed based on the distributed equivalent circuit model. Simulation is carried out on the basis of this distributed model. Furthermore, when a quench occurs in the superconducting DC cable in any basic unit equivalent circuit, only the corresponding basic unit equivalent circuit needs to be analyzed for quench. By means of block analysis, the problem of difficult quench analysis for the whole cable when accessing a long-distance DC power transmission system is solved, and the analysis efficiency of quench analysis is improved. It can timely guide the operation and maintenance personnel to optimize the maintenance of the superconducting DC cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic flowchart of a simulation modeling method for a long-distance superconducting DC cable provided by an embodiment of the present invention.

[0049] Figure 2 is a schematic structural diagram of a superconducting DC cable provided by an embodiment of the present invention.

[0050] Figure 3 is a schematic diagram of a distributed equivalent circuit model of a long-distance superconducting DC cable provided by an embodiment of the present invention.

[0051] Figure 4 is a diagram showing the relationship between quench heat and quench resistance transfer provided by an embodiment of the present invention.

[0052] Figure 5 is R provided by an embodiment of the present invention HTS -Q HTS curve schematic diagram.

[0053] Figure 6 is a schematic structural diagram of a simulation modeling device for a long-distance superconducting DC cable provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0055] To make the objectives, technical solutions, and advantages of this application clearer, the following will clearly and completely describe the technical solutions in this application in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description of the specification, claims, and above-mentioned drawings of this application are intended to cover non-exclusive inclusion.

[0057] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0058] Referring to "embodiments" herein means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears at various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0059] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0060] In the description of the embodiments of this application, the term "a plurality" refers to two or more (including two). Similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0061] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0062] As Figure 1 shown, a simulation modeling method for a long-distance superconducting DC cable provided by an embodiment of the present invention includes:

[0063] Step S1: Perform simulation modeling on the superconducting DC cable to obtain a superconducting DC cable simulation model; wherein, the superconducting DC cable simulation model includes: a superconducting layer and a copper skeleton layer;

[0064] Step S2: Based on the superconducting DC cable simulation model, construct a distributed equivalent circuit model of the long-distance superconducting DC cable; wherein, the distributed equivalent circuit model includes several basic unit equivalent circuits, each basic unit equivalent circuit corresponds to a superconducting DC cable section, and each basic unit equivalent circuit includes an equivalent resistance corresponding to the superconducting DC cable section, and the equivalent resistance is composed of the parallel connection of the superconducting layer resistance and the copper skeleton layer resistance;

[0065] Step S3: Construct a distributed model of the superconducting DC cable according to the distributed equivalent circuit model;

[0066] Step S4: Perform simulation on the distributed model. When a superconducting DC cable quench occurs in a basic unit equivalent circuit, assign an initial value to the quench resistance of the corresponding basic unit equivalent circuit to obtain a to-be-processed quench resistance; wherein, the quench resistance is the superconducting layer resistance during quenching;

[0067] Step S5: According to each to-be-processed quench resistance and a preset relationship curve, perform simulation iteration to determine the true value of the quench resistance of each basic unit equivalent circuit; wherein, the preset relationship curve is the relationship curve between the quench resistance and the quench heat;

[0068] Step S6: Feed back the true value of the quench resistance of each basic unit equivalent circuit to the superconducting DC cable operation and maintenance personnel, so that the operation and maintenance personnel can optimize the superconducting DC cable according to the true value of the quench resistance.

[0069] For step S1, the present invention uses the structure of a single-pole cold-insulated superconducting DC cable as Figure 2 shown for the simulation modeling of the superconducting DC cable.

[0070] In a preferred embodiment, the superconducting DC cable simulation model further includes: liquid nitrogen, an electrical insulation layer, and a thermal insulation layer; the superconducting layer, the electrical insulation layer, the liquid nitrogen, and the thermal insulation layer are sequentially wrapped outside the copper skeleton layer.

[0071] Specifically, as Figure 2 shown, the core of the single-pole cold-insulated superconducting DC cable is a copper skeleton layer, and the superconducting layer, the electrical insulation layer, the liquid nitrogen, and the thermal insulation layer are sequentially wrapped outside it.

[0072] In a preferred embodiment, constructing a distributed equivalent circuit model of a long-distance superconducting DC cable based on the superconducting DC cable simulation model includes: dividing the superconducting DC cable simulation model into several superconducting DC cable simulation sub-models based on a preset simulation accuracy; each superconducting DC cable simulation sub-model corresponds to a superconducting DC cable section; establishing a corresponding basic unit equivalent circuit for each superconducting DC cable simulation sub-model; and constructing a distributed equivalent circuit model of the long-distance superconducting DC cable according to the basic unit equivalent circuits.

[0073] In a preferred embodiment, each of the basic unit equivalent circuits further includes: a resistance and a capacitance to ground; the equivalent resistance and reactance of the superconducting DC cable are connected in series, and capacitances to ground are connected in parallel on both sides.

[0074] Specifically, after determining the hierarchical structure of the above superconducting DC cable simulation model, based on the required simulation accuracy and the required computational efficiency of the simulation, the superconducting DC cable simulation model is divided into several equal superconducting DC cable simulation sub-models, and each superconducting DC cable simulation sub-model corresponds to a section of the superconducting DC cable (i.e., the above superconducting DC cable section). It should be noted that since equal division is used in the division, the lengths of the divided superconducting DC cable sections should be equal. The preset simulation accuracy and the number of divided sections can be flexibly set according to the simulation analysis requirements to meet the requirements of different simulation scenarios.

[0075] For step S2, as Figure 3 shown, for each superconducting DC cable simulation sub-model, that is, each superconducting DC cable section, a corresponding basic unit equivalent circuit is established, and this basic unit equivalent circuit is a dynamic coupling unit circuit. Each basic unit equivalent circuit is as Figure 3 shown in the dashed box. Each basic unit equivalent circuit consists of an equivalent resistance R eq in series with an impedance L and an equivalent resistance R eq in parallel with a capacitance C; where the equivalent resistance R eq part is composed of the parallel combination of the superconducting layer resistance R HTS and the copper skeleton layer resistance R Cu The inductance and capacitance parameters per kilometer are 1.45 mH / km and 0.076 μF / km respectively, and the resistance parameter of the equivalent resistance is determined by the superconducting layer resistance RHTS and the resistance R of the copper skeleton layer Cu is obtained by parallel equivalence.

[0076] According to the equivalent circuits of each basic unit, a distributed equivalent circuit model of a long-distance superconducting DC cable can be obtained to construct a distributed equivalent circuit model of the superconducting DC cable.

[0077] In the present invention, when performing superconducting and quench simulation analyses, the resistance of the superconducting layer when the superconducting DC cable remains in the superconducting state is set to 0. The resistance of the superconducting layer in the quench state, i.e., the quench resistance, will have its calculation process described in the subsequent steps.

[0078] For step S3, a distributed model of the superconducting DC cable is constructed according to the distributed equivalent circuit model.

[0079] In a preferred embodiment, after constructing a distributed equivalent circuit model of a long-distance superconducting DC cable based on the superconducting DC cable simulation model, it further includes: for each basic unit equivalent circuit, obtaining the thermal parameters of the superconducting DC cable simulation model corresponding to each basic unit equivalent circuit; wherein, the thermal parameters include: the equivalent resistance of the superconducting DC cable, the heat absorbed by the superconducting tape, the heat capacity of each component of the superconducting tape, the liquid nitrogen coverage area, and the cable temperature; constructing a thermal model of the current basic unit equivalent circuit according to the thermal parameters; the constructing a distributed model of the superconducting DC cable according to the distributed equivalent circuit model includes: constructing a distributed model of the superconducting DC cable according to each basic unit equivalent circuit and the thermal model corresponding to each basic unit equivalent circuit.

[0080] Specifically, a thermal model is constructed for each basic unit equivalent circuit. This thermal model comprehensively considers the role of the refrigeration system after a quench occurs, i.e., considers the thermal effect during the quench process.

[0081] When a quench occurs in the superconducting DC cable, a quench resistance will appear, and at this time, a certain amount of Joule heat will be generated. The heat transfer process is as follows:

[0082] Q total = Q HTS + Q S + Q LN + Q e

[0083] Among them, Q total is the total Joule heat generated by the superconducting DC cable; Q HTS is the heat absorbed by each component of the superconducting tape; Q S is the heat absorbed by solid materials such as insulation; Q LN is the heat taken away by liquid nitrogen; Q e is the heat transferred to the outside.

[0084] The principle of quench is mainly caused by the current flowing through the superconducting DC cable exceeding its critical current. Since the duration of the fault current is short, the heat exchange between the cable and the external environment during the quench process can be ignored. Therefore, the entire heat transfer process of the cable during quench can be approximated as an adiabatic process. Ignoring the heat absorbed by the electrical insulation layer and the thermal insulation layer, the heat generated by the cable is all absorbed by the superconducting tape and liquid nitrogen, resulting in an increase in the temperature of the superconducting material in the superconducting layer. The temperature rise process corresponds to the thermal model of each basic unit and can be described as follows:

[0085] Q HTS =Q total -Q LN

[0086]

[0087]

[0088] Among them, R eq is the equivalent resistance of the superconducting DC cable; Q total is the total Joule heat generated by the superconducting DC cable; Q HTS is the heat absorbed by the superconducting tape; Q LN is the heat taken away by the liquid nitrogen; ΔT is the temperature difference between the liquid nitrogen and the superconducting material; h is the heat transfer coefficient, which is a function of the temperature difference between the liquid nitrogen and the superconducting material; A is the liquid nitrogen coverage area; T(t) is the cable temperature; T 0 is the initial reference temperature. During the subsequent simulation iteration process, T 0 is continuously updated. In each iteration, the obtained T is used as the T 0 in the next iteration. Initially, T 0 is 77K.

[0089] Connecting all the equivalent circuits of the basic units in series gives a distributed equivalent circuit model. The distributed model of the superconducting DC cable is obtained through the interaction of the dynamic parameters of the thermal model corresponding to each basic unit equivalent circuit and the distributed equivalent circuit model.

[0090] For steps S4 and S5, in system simulation, the above distributed model is connected to a long-distance DC power transmission system. Key parameters, including critical current density, quench resistance, copper skeleton layer resistance, real-time current, and operating temperature, are exchanged in real time between each basic unit equivalent circuit and its corresponding thermal model.

[0091] In a preferred embodiment, simulating the distributed model, when a superconducting DC cable in a basic unit equivalent circuit experiences a quench, assigning an initial value to the quench resistance of the corresponding basic unit equivalent circuit to obtain a quench resistance to be processed, includes: setting simulation parameters of the distributed model of the superconducting DC cable; wherein, the simulation parameters include: critical current; performing simulation on the distributed model based on the set simulation parameters; when the real-time current of any basic unit equivalent circuit exceeds the critical current, the superconducting DC cable in the corresponding section of the current basic unit equivalent circuit experiences a quench; assigning an initial value to the quench resistance of the current basic unit equivalent circuit to obtain a quench resistance to be processed.

[0092] The calculation of the copper skeleton layer resistance is carried out in the thermal model corresponding to the basic unit equivalent circuit during quench. In a preferred embodiment, after obtaining the quench resistance to be processed, it further includes: obtaining the length of the superconducting DC cable and the cross-sectional area of the copper skeleton layer in the corresponding section of the current basic unit equivalent circuit; determining the quench temperature according to the thermal model of the current basic unit equivalent circuit; calculating the resistance of the copper skeleton layer during quench based on the quench temperature, the length of the superconducting DC cable in the corresponding section of the current basic unit equivalent circuit, and the cross-sectional area of the copper skeleton layer.

[0093] Specifically, when performing simulation, first set simulation parameters, including critical current and initial temperature; when the real-time current of any basic unit exceeds the critical current, it is determined that the superconducting DC cable in the corresponding section of the current basic unit equivalent circuit experiences a quench. At this time, the superconducting layer resistance of the current basic unit equivalent circuit is the quench resistance, and an initial value R i (i = 0) is assigned to this quench resistance.

[0094] Obtain the length of the superconducting DC cable and the cross-sectional area of the copper skeleton layer in the corresponding section of the current basic unit equivalent circuit. Determine the quench temperature T according to the thermal model of the basic unit equivalent circuit.

[0095] Preferably, after obtaining the current quench temperature, relevant parameters dependent on temperature need to be updated immediately, mainly including critical current density and resistivity of copper.

[0096] The dependence relationship of the critical current density on temperature can be described as:

[0097]

[0098] wherein, T r is the initial reference temperature, which is 77K; T c is the critical temperature, which is 92K; the coefficient k = T c -T r ; in the present invention, a is set to 1.5; J cis the initial critical current density under the reference temperature condition.

[0099] The resistance of the copper skeleton layer of the superconducting DC cable is mainly determined by the resistivity of copper material at low temperature and its own size. The resistivity of copper at low temperature is as follows:

[0100] ρ Cu =(0.0084T - 0.4603)×10 -8 , 70K ≤ T < 250K

[0101] According to the cross-sectional area S of the copper skeleton layer, the length l of the superconducting DC cable, and the resistivity ρ of copper at low temperature Cu , the resistance R of the copper skeleton layer can be calculated using the formula Cu :

[0102]

[0103] Furthermore, calculate the true value of the quench resistance corresponding to the resistance of the superconducting layer in the quench state.

[0104] The superconducting DC cable is approximately considered to be in an adiabatic state during the quench period. The total heat generated by the quench is all absorbed by the superconducting layer and liquid nitrogen. The heat absorbed by the superconducting layer is used for the accumulation of the temperature rise heat of the superconducting DC cable itself. Combining the dependence relationship between the critical current density and temperature, it can be known that the critical current density is related to temperature. Combining the following superconducting E-J relationship, it can be known that the quench resistance value is closely related to the change of the critical current density. The superconducting E-J relationship is as follows:

[0105]

[0106] Among them, E 0 is the critical electric field strength.

[0107] According to the above relationship analysis, a transfer relationship can be established as Figure 4 shown for the quench heat Q HTS , the quench temperature T of the cable, the critical current density J C and the quench resistance R HTS . According to this transfer relationship, during the quench temperature rise process, the quench resistance R HTS is only related to its own quench heat Q HTS , and is therefore independent of the current waveform, frequency, and amplitude flowing through the current limiter. Therefore, whether in an AC system or a DC system, the quench resistance - quench heat curve (i.e., the preset relationship curve, which can be simply expressed as the R HTS -Q HTS curve) is the same in a short time after the superconducting DC cable quenches. A fixed quench heat value corresponds to a fixed quench resistance value, that is, according to this relationship curve, the quench resistance value can be obtained from the quench heat value. AsFigure 5 The following is the R HTS -Q HTS curve schematic diagram provided by the present invention.

[0108] In a preferred embodiment, the method for simulating and iteratively determining the true value of the quench resistance of each basic unit equivalent circuit according to each quench resistance to be processed and a preset relationship curve includes: for each quench resistance to be processed, performing a quench resistance value update operation until the iterative error is less than a preset difference threshold, and taking the quench resistance value to be processed at the current iteration as the true value of the quench resistance;

[0109] Wherein, the quench resistance value update operation includes: obtaining the current iteration current curve of the quench resistance to be processed according to the basic unit equivalent circuit including the quench resistance to be processed; determining the quench heat curve according to the thermal model corresponding to the basic unit equivalent circuit including the quench resistance to be processed; determining the quench resistance value to be processed at the next iteration according to the quench heat curve and the preset relationship curve; substituting the quench resistance value to be processed at the next iteration into the current basic unit equivalent circuit to obtain the current curve corresponding to the quench resistance value to be processed at the next iteration; and calculating the iterative error according to the current curve corresponding to the quench resistance value to be processed at the current iteration and the current curve corresponding to the quench resistance value to be processed at the next iteration.

[0110] Specifically, after assigning an initial value R i (i = 0) to the quench resistance, the superconducting layer resistance value in the corresponding basic unit equivalent circuit is replaced with R i , and the quench resistance after the value replacement is used as the quench resistance to be processed. After the value replacement is completed, the quench resistance value update operation is performed until the iterative error is less than the preset difference threshold, and the quench resistance value to be processed at the current iteration is taken as the true value of the quench resistance. When performing the quench resistance value update operation, the basic unit with the quench resistance value of R i is simulated to obtain the superconducting layer fault current change curve I-t at the quench resistance to be processed, and at the same time, the quench heat Q HTS is calculated by the thermal model corresponding to the basic unit equivalent circuit to obtain the quench heat curve Q HTS -t. According to the calculated quench heat Q HTS , checking the R HTS -Q HTS curve to obtain the quench resistance value R HTS to be processed at the next iteration and the R HTS -t curve of the quench resistance to be processed changing with time. Preferably, according to R HTS and R Cu , a new parallel equivalent resistance R eq can be calculated.Substitute the quench resistance value to be processed in the next iteration into the equivalent circuit of the current basic unit to obtain the current curve corresponding to the quench resistance value to be processed in the next iteration. Calculate the degree of coincidence between the current curve corresponding to the quench resistance value to be processed in the current iteration and the current curve corresponding to the quench resistance value to be processed in the next iteration. This degree of coincidence is the iteration error, which can be judged by calculating the Euclidean distance between the two curves. The Euclidean distance calculation formula is as follows:

[0111]

[0112] where i is the iteration number; j is the sampling point; I i+1 is the current at the (i + 1)-th iteration; I i is the current at the i-th iteration.

[0113] When the Euclidean distance d between the fault current curves obtained from the two most recent iterations is less than δ (a preset difference threshold, where δ = 1 - 6 in the present invention), it is considered that the iteration has converged. At this time, the quench resistance value to be processed in the current iteration is taken as the true value of the quench resistance. If not satisfied, repeat the above quench resistance value update operation until d is less than δ.

[0114] For step S6, after obtaining the true value of the quench resistance, the parallel equivalent resistance can be obtained by combining the resistance value of the corresponding copper skeleton layer in the quench state. Feed back the true value of the quench resistance corresponding to the superconducting layer resistance in the quench state, the copper skeleton layer resistance value, the current curve and the quench heat curve obtained during the simulation to the superconducting DC cable operation and maintenance personnel. The superconducting DC cable operation and maintenance personnel can optimize the design and ensure the safe operation of the superconducting DC cable based on the feedback parameters, and timely guide the operation and maintenance personnel to optimize the maintenance of the superconducting DC cable.

[0115] Based on the above method item embodiments, the present invention correspondingly provides device item embodiments.

[0116] As Figure 6 shown, an embodiment of the present invention provides a simulation modeling device for a long-distance superconducting DC cable, including: a distributed model modeling module, a simulation and simulation module, and a guidance and optimization module;

[0117] The distributed model modeling module is used to simulate and model the superconducting DC cable to obtain a superconducting DC cable simulation model. Among them, the superconducting DC cable simulation model includes a superconducting layer and a copper skeleton layer. A distributed equivalent circuit model of the long-distance superconducting DC cable is constructed based on the superconducting DC cable simulation model. Among them, the distributed equivalent circuit model includes a number of basic unit equivalent circuits. Each basic unit equivalent circuit corresponds to a superconducting DC cable section. Each basic unit equivalent circuit includes an equivalent resistance corresponding to the superconducting DC cable section. The equivalent resistance is composed of the parallel connection of the superconducting layer resistance and the copper skeleton layer resistance. A distributed model of the superconducting DC cable is constructed according to the distributed equivalent circuit model.

[0118] The simulation module is used to simulate the distributed model. When a superconducting DC cable quench occurs in a basic unit equivalent circuit, an initial value is given to the quench resistance of the corresponding basic unit equivalent circuit to obtain a to-be-processed quench resistance. Among them, the quench resistance is the superconducting layer resistance during quench. The true values of the quench resistances of each basic unit equivalent circuit are determined by simulation iteration according to each to-be-processed quench resistance and a preset relationship curve. Among them, the preset relationship curve is the relationship curve between the quench resistance and the quench heat.

[0119] The guidance and optimization module is used to feedback the true values of the quench resistances of each basic unit equivalent circuit to the superconducting DC cable operation and maintenance personnel, so that the operation and maintenance personnel can optimize the superconducting DC cable according to the true values of the quench resistances.

[0120] It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that they have a communication connection, which can be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art can understand and implement without creative efforts.

[0121] Those skilled in the art can clearly understand that for the convenience and simplicity, the specific working process of the device described above can refer to the corresponding process in the foregoing method embodiment, and will not be elaborated here.

[0122] Based on the foregoing method embodiment, the present invention correspondingly provides a terminal device embodiment.

[0123] An embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements a simulation modeling method for a long-distance superconducting DC cable described in any one of the present invention.

[0124] The terminal device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory.

[0125] The so-called processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The processor is the control center of the terminal device, and connects various parts of the entire terminal device through various interfaces and lines.

[0126] The memory can be used to store the computer program. The processor realizes various functions of the terminal device by running or executing the computer program stored in the memory and calling the data stored in the memory. The memory may mainly include a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function, etc.; the data storage area can store data created according to the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0127] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A simulation modeling method for a long-distance superconducting DC cable, characterized in that: include: The superconducting DC cable is simulated and modeled to obtain a superconducting DC cable simulation model; wherein the superconducting DC cable simulation model includes: a superconducting layer and a copper skeleton layer; A distributed equivalent circuit model of a long-distance superconducting DC cable is constructed based on a superconducting DC cable simulation model; wherein the distributed equivalent circuit model includes a plurality of basic unit equivalent circuits, each of which corresponds to a superconducting DC cable section, and each of which includes an equivalent resistance corresponding to the superconducting DC cable section, wherein the equivalent resistance is composed of a superconducting layer resistance and a copper skeleton layer resistance connected in parallel; Constructing a distributed model of a superconducting DC cable according to the distributed equivalent circuit model; The distributed model is simulated, and when a superconducting DC cable quench occurs in a basic unit equivalent circuit, an initial value is assigned to the quench resistance of the corresponding basic unit equivalent circuit to obtain the quench resistance to be processed; wherein the quench resistance is the resistance of the superconducting layer when the quench occurs; Determine the true value of the quench resistance of each basic unit equivalent circuit according to each quench resistance to be processed and a preset relationship curve by simulation iteration; wherein the preset relationship curve is a relationship curve between the quench resistance and the quench heat; The true value of the quench resistance of each basic unit equivalent circuit is fed back to the superconducting DC cable operation and maintenance personnel, so that the operation and maintenance personnel can optimize the superconducting DC cable according to the true value of the quench resistance.

2. A simulation modeling method for a long-distance superconducting DC cable according to claim 1, characterized in that: The method of constructing a distributed equivalent circuit model of a long-distance superconducting DC cable based on a superconducting DC cable simulation model includes: The superconducting DC cable simulation model is divided into a plurality of superconducting DC cable simulation sub-models based on a preset simulation accuracy; each superconducting DC cable simulation sub-model corresponds to a superconducting DC cable section; For each superconducting DC cable simulation sub-model, a corresponding basic unit equivalent circuit is established; A distributed equivalent circuit model of long-distance superconducting DC cable is constructed based on the equivalent circuits of each basic unit.

3. A simulation modeling method for a long-distance superconducting DC cable as claimed in claim 2, characterized in that: The superconducting DC cable simulation model also includes: liquid nitrogen, an electrical insulation layer and a thermal insulation layer; The copper skeleton layer is wrapped with a superconducting layer, an electrical insulating layer, liquid nitrogen and a heat insulating layer in sequence.

4. A simulation modeling method for a long-distance superconducting DC cable as claimed in claim 3, characterized in that: Each of the basic unit equivalent circuits further includes: a resistor and a capacitor to ground; The equivalent resistance and reactance of the superconducting DC cable are connected in series, and the ground capacitance is connected in parallel on both sides.

5. A simulation modeling method for a long-distance superconducting DC cable as claimed in claim 4, characterized in that: After building a distributed equivalent circuit model of a long-distance superconducting DC cable based on the superconducting DC cable simulation model, it also includes: For each basic unit equivalent circuit, obtain thermal parameters of a superconducting DC cable simulation model corresponding to each basic unit equivalent circuit; wherein the thermal parameters include: equivalent resistance of the superconducting DC cable, heat absorbed by the superconducting tape, heat capacity of each component of the superconducting tape, liquid nitrogen coverage area and cable temperature; Constructing a thermal model of the current basic unit equivalent circuit according to the thermal parameters; The method of constructing a distributed model of a superconducting DC cable according to the distributed equivalent circuit model comprises: A distributed model of the superconducting DC cable is constructed according to the equivalent circuits of each basic unit and the thermal models corresponding to the equivalent circuits of each basic unit.

6. A simulation modeling method for a long-distance superconducting DC cable as claimed in claim 5, characterized in that: The simulating the distributed model, when a superconducting DC cable quench occurs in a basic unit equivalent circuit, assigning an initial value to the quench resistance of the corresponding basic unit equivalent circuit to obtain the quench resistance to be processed, includes: Setting simulation parameters of a distributed model of a superconducting DC cable; wherein the simulation parameters include: critical current; Simulating the distributed model based on the set simulation parameters; When the real-time current of any basic unit equivalent circuit exceeds the critical current, the superconducting DC cable of the corresponding section of the current basic unit equivalent circuit is quenched; An initial value is assigned to the quench resistance of the current basic unit equivalent circuit to obtain the quench resistance to be processed.

7. A simulation modeling method for a long-distance superconducting DC cable as claimed in claim 6, characterized in that: After obtaining the quench resistor to be processed, the following steps are also included: Obtain the length of the superconducting DC cable and the cross-sectional area of ​​the copper skeleton layer in the corresponding section of the current basic unit equivalent circuit; Determine the quench temperature based on the thermal model of the current basic unit equivalent circuit; The resistance of the copper skeleton layer during quenching is calculated according to the quenching temperature, the length of the superconducting DC cable in the corresponding section of the current basic unit equivalent circuit, and the cross-sectional area of ​​the copper skeleton layer.

8. A simulation modeling method for a long-distance superconducting DC cable as claimed in claim 7, characterized in that: The method of iteratively simulating and determining the true value of the quench resistance of each basic unit equivalent circuit according to each quench resistance to be processed and a preset relationship curve comprises: For each quench resistor to be processed, a quench resistor value update operation is performed until the iteration error is less than a preset difference threshold, and the quench resistor value to be processed in the current iteration is used as the true value of the quench resistor; Wherein, the quench resistance value updating operation includes: According to the basic unit equivalent circuit including the quench resistor to be processed, a current curve of the quench resistor to be processed in the current iteration is obtained; Determine a quench thermal curve according to a thermal model corresponding to a basic unit equivalent circuit including a quench resistor to be processed; Determine the quench resistance value to be processed in the next iteration according to the quench thermal curve and the preset relationship curve; Substituting the quench resistance value to be processed in the next iteration into the current basic unit equivalent circuit, and obtaining the current curve corresponding to the quench resistance value to be processed in the next iteration; The iteration error is calculated according to the current curve corresponding to the quench resistance value to be processed in the current iteration and the current curve corresponding to the quench resistance value to be processed in the next iteration.

9. A simulation modeling device for a long-distance superconducting DC cable, characterized in that: include: Distributed model building module, simulation module and guidance optimization module; The distributed model modeling module is used to simulate and model the superconducting DC cable to obtain a superconducting DC cable simulation model; wherein the superconducting DC cable simulation model includes: a superconducting layer and a copper skeleton layer; a distributed equivalent circuit model of a long-distance superconducting DC cable is constructed based on the superconducting DC cable simulation model; wherein the distributed equivalent circuit model includes a number of basic unit equivalent circuits, each basic unit equivalent circuit corresponds to a superconducting DC cable section, each basic unit equivalent circuit includes an equivalent resistance corresponding to the superconducting DC cable section, and the equivalent resistance is composed of a superconducting layer resistance and a copper skeleton layer resistance in parallel; a distributed model of the superconducting DC cable is constructed according to the distributed equivalent circuit model; The simulation module is used to simulate the distributed model. When a superconducting DC cable quench occurs in a basic unit equivalent circuit, an initial value is assigned to the quench resistance of the corresponding basic unit equivalent circuit to obtain a quench resistance to be processed; wherein the quench resistance is the resistance of the superconducting layer when the quench occurs; the true value of the quench resistance of each basic unit equivalent circuit is determined by simulation iteration according to each quench resistance to be processed and a preset relationship curve; wherein the preset relationship curve is a relationship curve between the quench resistance and the quench heat; The guiding optimization module is used to feed back the true value of the quench resistance of each basic unit equivalent circuit to the superconducting DC cable operation and maintenance personnel, so that the operation and maintenance personnel can optimize the superconducting DC cable according to the true value of the quench resistance.

10. A terminal device, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, a simulation analysis method for a long-distance superconducting DC cable as claimed in any one of claims 1 to 8 is implemented.

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