Direct current change-over switch current parameter design method and related device

Abstract

The invention discloses a DC change-over switch current parameter design method and a related device, and the method comprises the steps: converting a topological structure of a target multi-terminal DC system into an equivalent circuit composed of a DC change-over switch and a line resistor; determining the state combination of each switch in the equivalent circuit, the resistance value range of each line resistor and the output power range of each converter station according to the system operation condition, and carrying out the iterative calculation of the current flowing through each DC change-over switch under each switch state combination based on the ranges; the switch conversion current of each switch under all state combinations is obtained, and finally the current design parameters of each direct-current change-over switch are determined, the most unfavorable current condition of the system under the possible operation working condition can be comprehensively covered, it is ensured that the direct-current change-over switch design is safe and reliable, and the stability and reliability of operation of the multi-terminal direct-current system are improved.

Description

Technical Field

[0001] This invention pertains to switch parameter configuration technology, and particularly relates to a method and device for designing current parameters of a DC-DC converter switch. Background Technology

[0002] Multi-terminal DC transmission systems, due to their ability to achieve flexible power exchange between multiple power sources and receiving ends, are gradually becoming an important direction for the development of modern power grids. In a multi-terminal DC system, each converter station forms a current path through a metal loop or grounding electrode loop, and the system operation mode is dynamically adjusted according to changes in load, power flow, and equipment status. In this process, DC transfer switches (such as ground loop transfer switches and metal loop transfer switches) undertake key functions such as loop switching, fault isolation, and operation mode adjustment. The electrical stress they withstand during switching and connection directly affects the safety and reliable operation of the system.

[0003] To ensure the safety of the switch under different operating conditions, engineering practice typically requires verification of the maximum current that the transfer switch may withstand during the system planning and equipment design phases. However, the topology of multi-terminal DC systems is complex, and the connection methods, line lengths, and electrical characteristics of grounding and metal circuits between different converter stations all affect the actual current distribution of the transfer switch. Furthermore, the power output of the converter stations varies with the operating scheme, and the output current of each station must satisfy the system's current balance, making the changes in transfer switch current under different operating modes even more complex.

[0004] In existing engineering projects, equivalent circuit analysis, power flow calculations, or simulations are commonly used to estimate the current in the switching loop. However, these methods still have shortcomings in multi-terminal DC systems: existing methods cannot cover all possible operating modes and switch combinations, and they cannot fully consider the variation range of line resistance and converter station output current. Furthermore, there is nonlinear coupling between the target switching current and system parameters, making analytical solutions difficult. In addition, different topologies often require specific analysis, and a universal calculation method is lacking.

[0005] Therefore, current engineering practice still lacks a systematic analysis method that can be applied to different topologies, cover various operating modes, fully consider the range of resistance and current changes, and accurately search for the maximum value of the target switching current. This poses a challenge to the reliable verification of the switching closing and breaking capabilities. Summary of the Invention

[0006] Based on this, the present invention aims to propose a design method and related device for DC transfer switch current parameters. Considering the transmission power and line impedance of a multi-terminal system, the method iteratively calculates the current flowing through the switch under different switch state combinations to determine the maximum current value of each DC transfer switch as the design parameter, so as to solve the problem of parameter configuration of transfer switches in a multi-terminal DC system.

[0007] In a first aspect, the present invention provides a method for designing current parameters of a DC-DC converter switch, comprising:

[0008] The topology of the target multi-terminal DC system is converted into an equivalent circuit including DC-DC switching and resistors;

[0009] The switching state combinations and resistance ranges of each resistor in the equivalent circuit are determined based on the operating conditions of the target multi-terminal DC system, as well as the power range of each converter station in the target multi-terminal DC system.

[0010] Based on the resistance range of each resistor and the power range of each converter station, the current flowing through each DC-DC transfer switch under each switch state combination is calculated iteratively to obtain the switching current of each DC-DC transfer switch under all switch state combinations.

[0011] The current design parameters for each DC-DC transfer switch are determined based on the switching current of each switch under all switching state combinations.

[0012] Furthermore, based on the resistance range of each resistor and the power range of each converter station, the current flowing through each DC-DC transfer switch under each switching state combination is iteratively calculated, resulting in the following switching current for each DC-DC transfer switch under all switching state combinations:

[0013] The output current range of each converter station is determined based on its power range.

[0014] Based on Kirchhoff's laws, the calculation relationship between the switching current of the DC transfer switch, the resistance value, and the output current of the converter station is established.

[0015] Using the resistance range of each resistor and the output current range of the converter station as iterative variables, the resistance-current combination corresponding to each switch state combination is determined.

[0016] Based on the calculation relationship, all resistance-current combinations are traversed and calculated to obtain the switching current of each DC-DC converter for each resistance-current combination under each switching state combination.

[0017] Furthermore, the current design parameters for each DC-DC transfer switch are determined based on the switching current of each switch under all switching state combinations, including:

[0018] For the current DC-DC transfer switch, the maximum current value under each switching state combination is determined based on the switching current corresponding to each resistance current combination under each switching state combination, and is recorded as the first current value of the current DC-DC transfer switch.

[0019] The maximum value among all the first current values ​​of the current DC-DC transfer switch is determined as the second current value, and the second current value is used as the current design parameter of the current DC-DC transfer switch.

[0020] Furthermore, converting the topology of the target multi-terminal DC system into an equivalent circuit including DC-DC switching and resistors includes:

[0021] Obtain the connection relationships of each converter station and conversion circuit in the target multi-terminal DC system;

[0022] Construct and determine the DC-side topology of the target multi-terminal DC system based on the connection relationships;

[0023] The DC-DC conversion switch and circuit in the DC-side topology are expressed in equivalent form, and the equivalent switching element and equivalent impedance element are obtained respectively.

[0024] Based on the electrical connection relationship of the target multi-terminal DC system, the equivalent switching elements and equivalent impedance elements are combined to construct the equivalent circuit of the target multi-terminal DC system, so that the target multi-terminal DC system is represented as an equivalent circuit structure composed of DC conversion switches and line impedance.

[0025] Furthermore, based on the electrical connection relationships of the target multi-terminal DC system, the equivalent circuit of the target multi-terminal DC system is constructed by combining equivalent switching elements and equivalent impedance elements, including:

[0026] By retaining the equivalent resistance in the equivalent impedance element and deleting the equivalent inductance in the equivalent impedance element, and combining the equivalent switching element and the equivalent resistance, an equivalent circuit consisting of a DC-DC conversion switch and a line resistance is constructed.

[0027] The line resistance in the equivalent circuit varies within a preset resistance range.

[0028] Furthermore, determining the switching state combinations in the equivalent circuit based on the operating conditions of the target multi-terminal DC system includes:

[0029] Obtain the operating parameters of the target multi-terminal DC system;

[0030] Determine the operating conditions of the target multi-terminal DC system based on the operating parameters;

[0031] The switching states of each DC-DC converter are combined and enumerated according to the operating conditions to obtain the switching state combinations.

[0032] Furthermore, determining the switching state combinations in the equivalent circuit based on the operating conditions of the target multi-terminal DC system includes:

[0033] Based on the physical connection relationship and logic state characteristics of each DC-DC conversion switch in the equivalent circuit, an initial switch state combination covering all states is generated.

[0034] Based on the operating conditions, control strategies, and protection linkage logic of the target multi-terminal DC system, determine the set of rule-based constraints used to limit the legality of switch states;

[0035] By eliminating invalid combinations from the initial switch state combinations based on the set of regularized constraints, valid switch state combinations that satisfy the current operating conditions of the target multi-terminal DC system are obtained.

[0036] Secondly, the present invention provides a DC-DC converter switch current parameter design device, comprising:

[0037] The equivalent modeling module is used to convert the topology of the target multi-terminal DC system into an equivalent circuit including DC-DC switching and resistors.

[0038] The condition acquisition module is used to determine the switching state combination and resistance range of each resistor in the equivalent circuit, as well as the power range of each converter station in the target multi-terminal DC system, based on the operating conditions of the target multi-terminal DC system.

[0039] The switching current calculation module is used to iteratively calculate the current flowing through each DC-DC converter switch under each switching state combination based on the resistance range of each resistor and the power range of each converter station, so as to obtain the switching switching current of each DC-DC converter under all switching state combinations.

[0040] The design parameter determination module is used to determine the current design parameters of each DC-DC transfer switch based on the switching current of each DC-DC transfer switch under all switching state combinations.

[0041] Thirdly, the present invention provides an electronic device including a memory storing computer-executable instructions and a processor, wherein when the computer-executable instructions are executed by the processor, the device performs the steps of the DC-DC converter switch current parameter design method provided in the first aspect.

[0042] Fourthly, the present invention provides a readable storage medium storing a computer-executable program that, when executed, can implement the various steps of the DC-DC converter switch current parameter design method provided in the first aspect.

[0043] Compared with existing parameter configuration methods, the present invention has the following advantages:

[0044] This invention proposes a method and related apparatus for designing current parameters of DC-DC transfer switches. Based on an equivalent circuit, the method determines the switch state combinations, resistance ranges, and converter station power range according to system operating conditions. It then performs iterative calculations based on the full combination of resistance and output current. This yields the switching current of each DC-DC transfer switch under all achievable operating modes without relying on empirical conditions or simplified models, ensuring that the current design parameters are consistent with the system's most unfavorable operating conditions and improving the accuracy and reliability of the design. Furthermore, by performing hierarchical maximization of the current results for each switch under all effective state combinations, the engineering applicability and safety margin of the parameter selection can be further improved. While maintaining consistency in the core calculation logic, the method's computational efficiency, scalability, and engineering application value are enhanced, solving the challenge of parameter configuration for transfer switches in multi-terminal DC systems. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0046] Figure 1 A flowchart illustrating the implementation of the DC-DC converter switch current parameter design method provided in this embodiment of the invention;

[0047] Figure 2 This is a schematic diagram of the topology of a four-terminal DC system provided in an embodiment of the present invention;

[0048] Figure 3 To Figure 2 A schematic diagram of the equivalent circuit structure obtained after equivalent processing;

[0049] Figure 4 To Figure 3 A schematic diagram of the equivalent circuit structure obtained by neglecting inductance in the schematic equivalent circuit.

[0050] Figure 5 A schematic diagram of the DC-DC converter switch current parameter design device provided in an embodiment of the present invention;

[0051] Figure 6 This is an electronic device architecture diagram provided for an embodiment of the present invention. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] See Figure 1 One embodiment of the present invention proposes a method for designing current parameters of a DC-DC converter switch, comprising the following steps:

[0054] Step S110. Convert the topology of the target multi-terminal DC system into an equivalent circuit including DC-DC switching and resistors.

[0055] This step first models the topology of the target multi-terminal DC system and converts it into an equivalent circuit consisting of DC transfer switches and line resistors. The topology conversion refers to abstracting the physical layout and complex equipment structure of the DC system into a steady-state circuit consisting only of DC transfer switches and line resistors, while keeping the actual electrical connections between the converter stations, electrode lines, metallic return lines, and DC transfer switches unchanged.

[0056] Specifically, the structural information of the target multi-terminal DC system is first obtained, including the DC side polarity of each converter station, the wiring method of the positive and negative branches, the composition of the metallic return line and grounding electrode path, the circuit structure of the transfer switch, and the electrical relationships of any parallel lines or cross-connected branches. Based on the above information, an electrical connection diagram of the system is established. All devices with conduction and switching functions are abstracted as equivalent switching elements, and lines, electrode lines, and other DC branches are abstracted as impedance elements to construct an electrical network that reflects the steady-state current distribution characteristics of the system.

[0057] During the construction of the equivalent circuit, a corresponding equivalent impedance value is assigned to each DC line, pole branch, or return path. This impedance can be determined based on factors such as line length, conductor type, cross-sectional area, and operating conditions, ensuring it reflects the actual electrical characteristics of each branch in the target DC system. By maintaining the connection relationship between equivalent switching elements and equivalent impedance elements consistent with the actual system, it is ensured that the current path of the equivalent circuit under different switching states matches the real system, providing an accurate basis for subsequent current solutions under multiple state combinations. As the equivalent switching elements and equivalent impedance elements are gradually associated, a DC-side equivalent circuit model for calculation is finally formed.

[0058] This model clearly expresses the circuit structure where the DC-DC transfer switch is located, as well as the current shunting characteristics of different impedance paths under conduction conditions. It can effectively cover various operating modes, circuit power distribution conditions and converter station power allocation requirements that may occur in multi-terminal DC systems, thereby meeting the requirements of subsequent large-scale combined iterative calculations.

[0059] In a further embodiment, considering that the current flowing through the DC-DC transfer switch is in a steady state before performing switching or opening operations, the influence of inductance in the steady-state current distribution is negligible. Therefore, the line impedance can be simplified to pure resistance characteristics. When constructing the equivalent circuit, the inductive elements in the line, reactor, and related loops can be equivalently deleted, retaining only the corresponding resistive elements as impedance expressions. This effectively reduces the complexity of the model, making the subsequent current iteration calculation process linear. This approach not only significantly improves computational efficiency but also avoids the instability problem caused by the coupling relationship introduced by inductance in large-scale state combination ergonomics, making the equivalent model more suitable for analyzing the maximum current of the DC-DC transfer switch.

[0060] In a further embodiment, the construction of the equivalent circuit can be adjusted according to whether the DC system adopts grounded electrode operation, metallic return line operation, or mixed operation, so that the model can cover more engineering scenarios.

[0061] Step S120. Determine the switching state combination and resistance range of each resistor in the equivalent circuit, as well as the power range of each converter station in the target multi-terminal DC system, based on the operating conditions of the target multi-terminal DC system.

[0062] The operating conditions upon which this step is based include the electrode connection status of the system under specific operating conditions, the power distribution of the converter station, the positive and negative pole operating modes, the operating status of the metallic return line or grounding electrode, and the possible operating conditions of the system under load scheduling, power switching, fault isolation, etc. These conditions directly determine the possible states of each switch in the equivalent circuit and the actual resistance range of each line, thereby affecting the current distribution of the DC-DC conversion switch.

[0063] Specifically, the operating parameters of the target multi-terminal DC system are first obtained. These parameters include, but are not limited to, the rated power of each converter station, the minimum and maximum adjustable output power, the power flow distribution requirements between stations, the operating mode of the electrode lines, the operating voltage level, and the line environmental conditions. Based on these parameters, the output current range of each converter station under specific operating conditions can be determined, ensuring that the output current of each converter station satisfies Kirchhoff's current law, thereby accurately representing the current load of each loop in the equivalent circuit. Subsequently, the possible on and off states of all DC transfer switches are combined and enumerated according to the operating mode to construct switch state combinations, which are used to represent the possible switch conduction paths of the system under all permissible operating conditions.

[0064] In a further embodiment, to reduce the number of switching state combinations and ensure computational efficiency, regularized constraints can be introduced. These constraints are set based on the target multi-terminal DC system's control strategy, protection linkage logic, equipment capacity limitations, and system operating procedures. They are used to eliminate impossible or unacceptable switching state combinations, thereby obtaining effective switching state combinations that meet the system's operating conditions.

[0065] In some embodiments, regularization constraints may include: prohibiting switch combinations that may cause a short circuit when closed simultaneously, consistency constraints that limit the direction of inter-electrode current, and switch interlocking conditions defined by protection logic. These regularization constraints can significantly reduce invalid combinations, improve the efficiency and reliability of subsequent iterative calculations, and ensure coverage of all possible actual operating states of the system.

[0066] In a further embodiment, the resistance value range in the equivalent circuit can be determined by determining the upper and lower limits for each line, loop and branch based on factors such as line length, conductor material, cross-sectional area, laying method and ambient temperature. These resistance value ranges are used to sample or traverse different resistance value combinations during subsequent iterative calculations to simulate the impact of line temperature changes, resistor aging or other operating conditions on current distribution.

[0067] In a further embodiment, the resistance range can be dynamically adjusted by establishing a resistance-temperature function model, making the iterative calculation closer to actual operating conditions. A more preferred implementation can set the resistance range separately for different operating modes (such as ground electrode mode, metallic loop mode, or mixed mode) to cover the resistance fluctuations that may occur in the system under various modes.

[0068] In determining the power range of converter stations, this embodiment not only considers the rated power, but also sets upper and lower limits in combination with power flow distribution schemes, system scheduling instructions and extreme operating conditions, so as to ensure that the output current of each converter station can cover the most unfavorable operating conditions that may occur in the system during iterative calculations.

[0069] In a further embodiment, the power range of the converter station can be combined with the voltage control strategy to establish a power-current-voltage constraint relationship. This ensures that the switching current result obtained by iterative calculation is achievable in actual engineering and provides a safety margin for the selection of subsequent design parameters.

[0070] This step provides a clear range or set of resistance values ​​for each line in the system, output current for each converter station, and all possible combinations of switch states, enabling the acquisition of the maximum switching current for each DC-DC converter under all possible operating conditions.

[0071] Step S130. Based on the resistance range of each resistor and the power range of each converter station, iteratively calculate the current flowing through each DC-DC converter under each switch state combination to obtain the switching current of each DC-DC converter under all switch state combinations.

[0072] This step, based on the resistance ranges of each resistor in the equivalent circuit determined in step S120, the output current ranges of each converter station, and all switch state combinations, iteratively calculates the current flowing through each DC-DC converter switch under each switch state combination, thereby obtaining the switching current of each DC-DC converter switch under all switch state combinations. The iterative calculation refers to traversing all combinations of resistors and converter station output currents, using the current distribution principle to calculate the actual current value of the target DC-DC converter switch for each combination, and recording the results. This is used as the basis for determining the current design parameters of the switch.

[0073] Specifically, firstly, based on Kirchhoff's current law, the current calculation relationship for each DC-DC transfer switch is established in the equivalent circuit. This relationship describes the nonlinear coupling characteristics between the switch current and the line resistance and converter station output current; that is, the current of each switch is not only affected by the resistance of its own circuit, but also closely related to the current distribution of other parallel circuits and adjacent converter stations. During the iterative calculation, using the resistance range and the converter station output current range as independent variables, a full combination traversal is performed on the target switches, calculating the switching current of each switch under the current resistance-current combination, and recording the results as the current set of the switch under the current state combination. This method ensures that the current distribution of the target DC-DC transfer switch is completely covered under all possible operating conditions.

[0074] In a further embodiment, the iterative calculation process can be divided into multiple sub-steps to improve computational accuracy and efficiency. For example, firstly, the output current range of the converter station is discretized and sampled, dividing the continuous power range into several step sizes, each corresponding to an output current value; subsequently, the line resistance range is segmented and sampled, dividing the resistance range into discrete points so that the switching current can be calculated for each resistance-current combination. Through this discretized iteration, computational accuracy and computational load can be effectively balanced, enabling reliable switching current to be obtained even in large multi-terminal DC systems.

[0075] In some embodiments, to enhance the feasibility of iterative calculations, a priority calculation mechanism may be introduced, that is, based on experience or system power flow patterns, priority is given to calculating resistance values ​​or output current combinations that may result in large switching currents.

[0076] In a preferred embodiment, iterative calculation can be combined with parallel computing technology, distributing different switching state combinations and resistance-current combinations to multiple computing units or threads for simultaneous calculation, thereby further improving computational efficiency. Furthermore, by establishing a caching or indexing mechanism, the results of repeatedly calculated sub-loop currents can be saved, reducing the number of repeated calculations and optimizing resource consumption and time overhead in the iteration process.

[0077] In a further embodiment, the nonlinear relationship between current and resistance in the iterative calculation can be approximated by combining the topological characteristics of the equivalent circuit model. For example, Monte Carlo sampling, heuristic search, or gradient analysis methods can be used to quickly locate the resistance-current combination that may generate the maximum switching current, thereby accelerating the solution of the maximum value while ensuring accuracy. This method is particularly suitable for multi-terminal DC systems with a large number of parallel loops or complex interconnected networks, making the iterative calculation not only comprehensive but also efficient.

[0078] By implementing this step, the current set of each DC transfer switch under all switching state combinations is fully calculated, serving as the basis for the switch current design parameters. This step ensures that no matter what permissible operating conditions the system is under, the designed switch current parameters can cover the maximum current that may occur under the most unfavorable operating conditions, thus improving the safety and reliability of the DC system.

[0079] Step S140. Determine the current design parameters of each DC-DC transfer switch based on the switching current of each DC-DC transfer switch under all switching state combinations.

[0080] The current design parameters determined in this step are the maximum permissible current values ​​selected for engineering design, selection, or safety margin assessment for each DC transfer switch. These values ​​should cover the maximum transfer current that the switch may withstand under all permissible operating conditions, thereby ensuring the safety, reliability, and stability of the system operation.

[0081] Specifically, for each DC-DC transfer switch, the current set corresponding to all switching state combinations is analyzed to determine the maximum current value under each switching state combination, which is denoted as the first current value of the switch under that combination. Subsequently, all first current values ​​of the same DC-DC transfer switch are compared, and the maximum value is found and denoted as the second current value. This second current value is the current design parameter used in the engineering design of the current DC-DC transfer switch, which can cover the most unfavorable current conditions of the switch under all possible operating conditions. Through this two-stage maximum maximization method, the current characteristics of the switch under different state combinations can be accurately reflected, while ensuring the safety margin of the design parameters.

[0082] In some embodiments, step S140 can be combined with the visualization analysis of the iterative calculation results to graphically present the current distribution under different switching state combinations, facilitating engineers to identify the most unfavorable operating conditions and providing a reference for subsequent switch selection, protection settings, and operational strategy optimization. In a more preferred embodiment, an automated algorithm can be introduced to intelligently calculate the switch current design parameters by traversing the current set of all switching state combinations and automatically identifying the second current value, reducing manual intervention and improving design efficiency and accuracy.

[0083] In a further embodiment, for switches in a multi-terminal DC system that may have mutual influence or series constraints, the current coupling relationship between adjacent switches can be considered during the determination of the second current value. For example, by analyzing the current distribution when multiple switches in a specific circuit are simultaneously turned on, the current design parameters of individual switches can be further modified to ensure a safety margin while considering the overall characteristics of the circuit. This method is particularly suitable for systems with complex multi-terminal topologies or those containing parallel lines or inter-pole interconnection branches, making the current design parameters more consistent with actual engineering requirements.

[0084] This step ensures that the current design parameters of each DC-DC transfer switch can cover all permissible switch state combinations and the most unfavorable operating conditions under various resistance and current variation ranges. This provides comprehensive protection for the safe and reliable operation of DC-DC transfer switches in multi-terminal DC systems and provides a scientific basis for system design, equipment selection, and subsequent engineering construction.

[0085] The invention will be further illustrated below with specific examples.

[0086] Figure 2 The diagram illustrates a topology for a four-terminal DC power system. To meet operational requirements, three of the converter stations are equipped with Metal Loop Transfer Switches (MRTB) and Earth Loop Transfer Switches (ERTB), while the other converter station is not equipped with either MRTB or ERTB. The converter station without a DC transfer switch relies on the opposite station to perform current conversion.

[0087] right Figure 2 The conversion circuit is equivalently processed, transforming it into an equivalent circuit consisting of a grounding electrode circuit and a metal circuit, as shown in the figure. Figure 3 As shown. Regarding the calculation of the switching current of the transfer switch, considering that the current flowing through the DC transfer switch is in a steady state before it switches off, the influence of the inductance in the circuit can be ignored when calculating the switching current. The focus is on the influence of the resistance in the switching loop on the current distribution. The equivalent circuit after ignoring the inductance is as follows: Figure 4 As shown.

[0088] Determine based on system operating conditions Figure 4The resistance range of all variable resistors in the switching circuit. When determining the resistance range, the influence of factors such as line length and temperature on the line resistance must be considered.

[0089] Based on system requirements, determine all operating modes involving the switching of transfer switches and the power range of each converter station in this DC project. Simultaneously, based on the power range of each converter station, determine the output current range of each converter station. The output current of each converter station must satisfy Kirchhoff's Current Law. Figure 4 For example, this DC system needs to meet the following requirements at all times. .

[0090] Determine all possible and valid switching state combinations for MRTB and ERTB, and analyze the current flowing through each DC-DC converter switch under each switching state combination based on the resistance shunt relationship.

[0091] by Figure 4 For example, assuming that in a selected combination of switching states, both MRTB and ERTB of converter station A are closed, while only MRTB is closed and ERTB is open in converter stations B and C, the MRTB current flowing through converter station A is calculated as follows:

[0092]

[0093] The current flowing through ERTB in converter station A is calculated as follows:

[0094]

[0095] As can be seen from the above current calculations, the magnitude of the switch current is mainly affected by the line resistance of the relevant grounding electrode circuit and the metal circuit, as well as the output current of each converter station. These variables vary within their range and have a complex nonlinear relationship with the target switch current, making it difficult to directly solve for the maximum value analytically. Therefore, it is necessary to perform combined iterative calculations on all relevant resistance and current variables in the formula to search for the maximum value of the target switch current.

[0096] The system iteratively calculates the current flowing through each switch under the current switching state combination within the current resistance and power range, in order to obtain the maximum current flowing through each switch under the current switching state combination. This process is repeated to calculate and determine the maximum current of each switch under other switching state combinations. Finally, for the same DC-DC converter switch, the maximum value of its maximum current under all switching state combinations is determined as its current design parameter.

[0097] The disclosed method can be implemented using various types of devices. Therefore, the present invention also discloses an apparatus corresponding to the above method, and specific embodiments are given below for detailed description.

[0098] like Figure 5As shown, one embodiment of the present invention provides a DC-DC converter switch current parameter design device, comprising:

[0099] Equivalent modeling module 502 is used to convert the topology of the target multi-terminal DC system into an equivalent circuit including DC-DC switching and resistors;

[0100] The condition acquisition module 504 is used to determine the switching state combination and resistance range of each resistor in the equivalent circuit, as well as the power range of each converter station in the target multi-terminal DC system, based on the operating conditions of the target multi-terminal DC system.

[0101] The switching current calculation module 506 is used to iteratively calculate the current flowing through each DC-DC converter switch under each switching state combination based on the resistance range of each resistor and the power range of each converter station, so as to obtain the switching switching current of each DC-DC converter under all switching state combinations.

[0102] The design parameter determination module 508 is used to determine the current design parameters of each DC-DC transfer switch based on the switching current of each DC-DC transfer switch under all switching state combinations.

[0103] The device provided in this application embodiment has the same implementation principle and technical effect as the aforementioned method embodiment. For the sake of brevity, any parts not mentioned in the device embodiment can be referred to the corresponding content in the aforementioned method embodiment.

[0104] The methods and related apparatuses mentioned in the above embodiments are described with reference to the method flowcharts and / or structural diagrams provided in the embodiments of this application. Specifically, each block of the method flowchart and / or structural diagram, as well as combinations of 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, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the process. Figure 1 A schematic diagram of one or more processes and / or structures. Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 A schematic diagram of one or more processes and / or structures. Figure 1The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 A process or multiple processes and / or structures illustrate the steps of the functions specified in one or more boxes.

[0105] The following embodiments illustrate the application of this method to a computer device. It is understood that the computer device can be any device with computing and processing capabilities, including but not limited to servers or personal laptops. In one embodiment, the computer device can be an application server, which can be a server used to run the application under test.

[0106] See Figure 6 This document illustrates a hardware block diagram of an electronic device intended to represent various forms of digital computers, such as laptops, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present application described and / or claimed herein.

[0107] like Figure 6 As shown, the electronic device includes: at least one processor 1, at least one communication interface 2, at least one memory 3, and at least one communication bus 4;

[0108] In this embodiment of the application, the number of processor 1, communication interface 2, memory 3, and communication bus 4 is at least one, and processor 1, communication interface 2, and memory 3 communicate with each other through communication bus 4;

[0109] Processor 1 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

[0110] Memory 3 may include high-speed RAM, and may also include non-volatile memory, such as at least one disk storage device;

[0111] The memory stores a program, which the processor can call. The program is used to implement the various processing steps of the aforementioned DC-DC converter switch current parameter design scheme.

[0112] This invention also provides a readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements various processing flows of the DC-DC converter switch current parameter design scheme provided in any possible implementation of the above embodiments and / or in combination with the embodiments.

[0113] The invention has been described in particular detail above with respect to possible scenarios, and those skilled in the art will recognize that the invention can be practiced through other embodiments. Specific naming of components, capitalization of terms, attributes, data structures, or any other programming or structural aspects are not mandatory or important, and the mechanisms or features of implementing the invention may have different names, forms, or procedures. The system can be implemented through a combination of hardware and software (as described), entirely through hardware elements, or entirely through software elements. The specific division of functions among the various system components described herein is merely exemplary and not mandatory; rather, the functions performed by a single system component can be performed by multiple components, or the functions performed by multiple components can be performed by a single component.

[0114] Those skilled in the art should understand that the various steps of the disclosed methods can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using device-executable program code, which can then be stored in a storage device for execution by the computing device. Alternatively, they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Therefore, the embodiments disclosed in this invention are not limited to any specific hardware and software combination.

[0115] The programs (also referred to as programs, software, software applications, or code) executable by these computing devices include machine instructions of a programmable processor and can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. As used herein, the terms “machine-readable medium” and “computer-readable medium” refer to any computer program product, device, and / or apparatus (e.g., disk, optical disk, memory, programmable logic device (PLD)) used to provide machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term “machine-readable signal” refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0116] Certain aspects of this invention include the process steps and instructions described herein in algorithmic form. It should be noted that the process steps and instructions of this invention can be implemented in software, firmware, and / or hardware, and when implemented in software, they can be downloaded, stored on various operating systems and operated from said platforms.

[0117] Those skilled in the art will understand that the structures shown in the figures are merely block diagrams of some structures related to the present application and do not constitute a limitation on the terminal device to which the present application is applied. Specific terminal devices may include more or fewer components than those shown in the figures, or combine certain components, or have different component arrangements.

[0118] In the description of this specification, the use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "possible design," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0119] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0120] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing current parameters of a direct current transfer switch, characterized in that, The method comprises the following steps: Converting the topology structure of a target multi-terminal DC system into an equivalent circuit comprising DC conversion switches and resistors; Determining the switch state combination and the resistance range of each resistor in the equivalent circuit according to the operating conditions of the target multi-terminal DC system, and determining the power range of each converter station in the target multi-terminal DC system; Based on the resistance range of each resistor and the power range of each converter station, the current flowing through each DC conversion switch under each switch state combination is iteratively calculated to obtain the switching current of each DC conversion switch under all switch state combinations; Determining the current design parameter of each DC conversion switch according to the switching current of each DC conversion switch under all switch state combinations.

2. The method of claim 1, wherein, The method comprises the following steps: Determining the converter station output current range according to the power range of each converter station; Based on Kirchhoff's law, a calculation relationship between the switching current of the DC conversion switch and the resistance and the converter station output current is established; Taking the resistance range of each resistor and the converter station output current range as the iteration variables, the resistance current combination corresponding to each switch state combination is determined; According to the calculation relationship, all resistance current combinations are calculated to obtain the switching current of each DC conversion switch corresponding to each resistance current combination under each switch state combination.

3. The method of claim 2, wherein, The method comprises the following steps: For the current DC conversion switch, according to the switching current corresponding to each resistance current combination under each switch state combination, the maximum current value of the current DC conversion switch under each switch state combination is determined, which is recorded as the first current value of the current DC conversion switch; The maximum value of all the first current values of the current DC conversion switch is determined as the second current value, which is used as the current design parameter of the current DC conversion switch.

4. The method of claim 1, wherein, The method comprises the following steps: Obtaining the connection relationship between each converter station and the conversion loop in the target multi-terminal DC system; According to the connection relationship, the DC side topology structure of the target multi-terminal DC system is constructed; The DC conversion switches and lines in the DC side topology structure are equivalently expressed to obtain equivalent switch elements and equivalent impedance elements, respectively; According to the electrical connection relationship of the target multi-terminal DC system, the equivalent switch elements and equivalent impedance elements are combined to construct the equivalent circuit of the target multi-terminal DC system, so that the target multi-terminal DC system is represented as an equivalent circuit structure composed of DC conversion switches and line impedances.

5. The method of claim 4, wherein, The method comprises the following steps: The equivalent resistance in the equivalent impedance element is reserved, the equivalent inductance in the equivalent impedance element is deleted, the equivalent switch element and the equivalent resistance are combined, and an equivalent circuit composed of a direct current conversion switch and a line resistance is constructed, and the line resistance in the equivalent circuit changes in a preset resistance value range.

6. The method of claim 1, wherein, The switch state combination in the equivalent circuit is determined according to the operation condition of the target multi-terminal direct current system. An operation parameter of a target multi-terminal direct current system is acquired. Each operation condition of the target multi-terminal direct current system is determined according to the operation parameter. Switch states of each direct current conversion switch are combined and enumerated according to the operation condition, and a switch state combination is obtained.

7. The method of claim 1, wherein, The switch state combination in the equivalent circuit is determined according to the operation condition of the target multi-terminal direct current system. An initial switch state combination covering all states is generated based on physical connection relationships and logical state characteristics of each direct current conversion switch in the equivalent circuit. A regularized constraint set for limiting switch state legality is determined according to an operation condition, a control strategy and a protection linkage logic of the target multi-terminal direct current system. Invalid combinations in the initial switch state combination are eliminated based on the regularized constraint set, and an effective switch state combination satisfying a current operation condition of the target multi-terminal direct current system is obtained.

8. A DC transfer switch current parameter design apparatus, characterized by comprising: a DC transfer switch current parameter design device; and a DC transfer switch current parameter design device. The method comprises: An equivalent modeling module is configured to convert a topological structure of a target multi-terminal direct current system into an equivalent circuit comprising direct current conversion switches and resistances. A condition acquisition module is configured to determine a switch state combination in the equivalent circuit and a resistance value range of each resistance according to an operation condition of the target multi-terminal direct current system and a power range of each converter station in the target multi-terminal direct current system. A switch current calculation module is configured to perform iterative calculation on currents flowing through each direct current conversion switch under each switch state combination based on the resistance value range of each resistance and the power range of each converter station, and obtain switch conversion currents of each direct current conversion switch under all switch state combinations. A design parameter determination module is configured to determine current design parameters of each direct current conversion switch according to the switch conversion currents of each direct current conversion switch under all switch state combinations.

9. An electronic device, comprising: The device comprises a memory storing computer executable instructions and a processor, and when the computer executable instructions are executed by the processor, the device performs the direct current conversion switch current parameter design method of any one of claims 1-7.

10. A readable storage medium, characterized by, The computer executable program is stored, and when the program is executed, the direct current conversion switch current parameter design method of any one of claims 1-7 can be realized.

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