Determination method, device and equipment of direct-current power transmission system and medium

Abstract

The embodiment of the invention discloses a determination method and device of a direct current power transmission system, equipment and a medium. The method comprises the following steps: determining converter station information of a direct current converter station in a target direct current power transmission system; determining power transmission line information in the target direct-current power transmission system according to the converter station information based on a line planning model; determining at least one initial topology scheme of the DC converter station according to the converter station information; performing index evaluation on each initial topology scheme of the direct current converter station, and determining a target topology scheme in each initial topology scheme according to an index evaluation result; and determining a target DC power transmission system according to the converter station information, the power transmission line information and the target topology scheme of the DC converter station. According to the technical scheme provided by the embodiment of the invention, a safe and reliable topology scheme of the DC converter station and a connection scheme of the power transmission line with the lowest cost can be determined, so that the safety stability, reliability and economical efficiency of the DC power transmission system are improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of power system, and particularly relate to a determination method, device, equipment and medium of a direct current transmission system. BACKGROUND

[0002] The direct current transmission system is a power transmission technology that converts alternating current into direct current for long-distance transmission, and then converts the direct current back into alternating current. It mainly consists of direct current converter stations (including rectifier stations and inverter stations) and direct current transmission lines, and is widely used in fields such as long-distance high-capacity power transmission, submarine cable power transmission, and interconnection of different frequency power grids.

[0003] However, the existing direct current transmission system is often determined based on experience, resulting in poor stability, low reliability, and poor economy of the direct current transmission system. SUMMARY

[0004] Embodiments of the present application provide a determination method, device, equipment and medium of a direct current transmission system, which can determine a topology scheme of a safe and reliable direct current converter station and a connection scheme of a transmission line with the lowest cost, thereby improving the safety and stability, reliability and economy of the direct current transmission system.

[0005] According to an aspect of the present application, a determination method of a direct current transmission system is provided, comprising:

[0006] determining converter station information of a direct current converter station in a target direct current transmission system; wherein the converter station information includes converter station distribution information, converter station quantity and converter station capacity;

[0007] determining transmission line information in the target direct current transmission system based on the converter station information based on a line planning model; wherein the transmission line information includes a line connection scheme and a line capacity;

[0008] determining at least one initial topology scheme of the direct current converter station according to the converter station information;

[0009] performing index evaluation on each of the initial topology schemes of the direct current converter station, and determining a target topology scheme from each of the initial topology schemes according to the index evaluation result;

[0010] determining the target direct current transmission system according to the converter station information, the transmission line information and the target topology scheme of the direct current converter station.

[0011] According to another aspect of the present application, a determination device of a direct current transmission system is provided, comprising:

[0012] The converter station information determination module is configured to determine converter station information of a DC converter station in the target DC power transmission system, wherein the converter station information comprises converter station distribution information, a number of converter stations, and a converter station capacity.

[0013] The line information determination module is configured to determine transmission line information in the target DC power transmission system based on a line planning model and according to the converter station information, wherein the transmission line information comprises a line connection scheme and a line capacity.

[0014] The initial topology scheme determination module is configured to determine at least one initial topology scheme of the DC converter station according to the converter station information.

[0015] The target topology scheme determination module is configured to perform index evaluation on each of the initial topology schemes of the DC converter station, and determine a target topology scheme from the initial topology schemes according to an index evaluation result.

[0016] The target DC power transmission system determination module is configured to determine the target DC power transmission system according to the converter station information, the transmission line information, and the target topology scheme of the DC converter station.

[0017] Optionally, the converter station information determination module can be configured to determine at least one target operation mode corresponding to the DC converter station, determine power values of the DC converter station under each target operation mode, wherein the number of power values is consistent with the number of target operation modes, and determine a maximum value in the power values as the converter station capacity of the DC converter station.

[0018] Optionally, the line information determination module can be configured to, before determining the transmission line information in the target DC power transmission system based on the line planning model and according to the converter station information, construct a target function with the minimum sum of new line costs in the target DC power transmission system as the target, construct a power conservation constraint condition according to power data of a target line and power data of the DC converter station, wherein the target line is a transmission line connected to the DC converter station, construct a capacity constraint condition according to the power data of the target line and capacity data of the target line, construct a sectional capacity constraint condition according to sectional capacity data of the target line and the capacity data of the target line, and construct the line planning model according to the target function, the power conservation constraint condition, the capacity constraint condition, and the sectional capacity constraint condition.

[0019] Optionally, the index evaluation further comprises a power operation range index evaluation of the converter station; the target topology scheme determination module can be configured to: determine the DC converter station in the initial topology scheme as a target converter station; determine active power and reactive power of the target converter station; determine a power operation range corresponding to the target converter station according to the active power and the reactive power of the target converter station; and determine that the initial topology scheme satisfies the power operation range index evaluation of the converter station if the power demand of the target converter station is within the power operation range, wherein the power demand of the target converter station comprises power demands of the target converter station in all target operation modes.

[0020] Optionally, the index evaluation further comprises an access point voltage support capability index evaluation; the target topology scheme determination module can be configured to: determine the DC converter station in the initial topology scheme as a target converter station when the DC converter station is a newly-built converter station; determine no-load voltage and access voltage of the grid access point; wherein the no-load voltage is voltage of the grid access point before the target converter station accesses the grid, and the access voltage is voltage of the grid access point after the target converter station accesses the grid in the target operation mode; calculate voltage support strength of the grid access point corresponding to the target operation mode according to the no-load voltage and the access voltage of the grid access point; and determine that the initial topology scheme satisfies the access point voltage support capability index evaluation if the voltage support strength of the grid access point corresponding to all target operation modes is greater than a voltage support strength threshold.

[0021] Optionally, the index evaluation further comprises a multi-DC interaction index evaluation; the target topology scheme determination module can be configured to: determine the DC converter station in the initial topology scheme as a target converter station when the DC converter station is a newly-built converter station; determine a target AC system connected to the target converter station; determine a target existing line connected to the target AC system before the target converter station accesses the grid; determine first voltage stiffness and second voltage stiffness of the target existing line; wherein the first voltage stiffness is voltage stiffness of the target existing line before the target converter station accesses the grid, and the second voltage stiffness is voltage stiffness of the target existing line after the target converter station accesses the grid in the target operation mode; calculate a multi-DC feeding no-load voltage drop factor of the target existing line corresponding to the target operation mode according to the first voltage stiffness and the second voltage stiffness of the target existing line; and determine that the initial topology scheme satisfies the multi-DC interaction index evaluation if the multi-DC feeding no-load voltage drop factor of the target existing line corresponding to all target operation modes is less than a drop factor threshold.

[0022] Optionally, the target topology scheme determination module can be further configured to: calculate converter station cost of the DC converter station in the initial topology scheme if the initial topology scheme satisfies the index evaluation; and determine the initial topology scheme with the minimum converter station cost as the target topology scheme.

[0023] According to another aspect of the present application, there is provided an electronic device comprising:

[0024] at least one processor; and

[0025] a memory communicatively connected with the at least one processor; wherein

[0026] the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to perform the determination method of the direct current power transmission system according to any one of the embodiments of the present application.

[0027] According to another aspect of the present application, there is provided a computer readable storage medium storing computer instructions for enabling a processor to implement the determination method of the direct current power transmission system according to any one of the embodiments of the present application when executed by the processor.

[0028] The technical scheme of the embodiments of the present application determines the converter station information of the direct current converter station in the target direct current power transmission system, and determines the power transmission line information in the target direct current power transmission system based on the line planning model according to the converter station information, and then determines at least one initial topology scheme of the direct current converter station according to the converter station information, performs index evaluation on each initial topology scheme of the direct current converter station, and determines the target topology scheme in each initial topology scheme according to the index evaluation result, so as to determine the target direct current power transmission system according to the converter station information, the power transmission line information and the target topology scheme, thereby solving the problems of poor stability, low reliability and poor economy of the existing direct current power transmission system, and being capable of determining the topology scheme of the safe and reliable direct current converter station and the connection scheme of the power transmission line with the lowest cost, thereby improving the safety and stability, reliability and economy of the direct current power transmission system.

[0029] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0031] Figure 1 is a flowchart of a determination method of a direct current power transmission system provided by the first embodiment of the present application;

[0032] Figure 2 is a flow chart of a method for determining a DC power transmission system according to an embodiment of the present application;

[0033] Figure 3 is a schematic diagram of a cost-capacity curve of a DC power transmission line according to an embodiment of the present application;

[0034] Figure 4 is a schematic diagram of a two-dimensional plane according to an embodiment of the present application;

[0035] Figure 5 is a schematic diagram of a Thevenin equivalent circuit according to an embodiment of the present application;

[0036] Figure 6 is a schematic diagram of another Thevenin equivalent circuit according to an embodiment of the present application;

[0037] Figure 7 is a schematic diagram of a device for determining a DC power transmission system according to an embodiment of the present application;

[0038] Figure 8 is a schematic diagram of an electronic device for implementing a method for determining a DC power transmission system according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] In order to make the personnel in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0040] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] Embodiment One

[0042] Figure 1is a flowchart of a determination method of a direct current power transmission system provided by an embodiment of the present application. The embodiment can be applicable to the case of determining a topology scheme of a safe and reliable direct current converter station and a connection scheme of a power transmission line with the lowest cost. The method can be executed by a determination device of the direct current power transmission system. The device can be realized by software and / or hardware and can be directly integrated in an electronic device that executes the method. The electronic device can be a terminal device or a server device. The present application does not limit the type of the electronic device that executes the determination method of the direct current power transmission system. Specifically, as shown in Figure 1 The determination method of the direct current power transmission system can include the following steps.

[0043] S110, determining converter station information of a direct current converter station in a target direct current power transmission system; wherein the converter station information includes converter station distribution information, a number of converter stations and a converter station capacity.

[0044] The target direct current power transmission system can be a direct current power transmission system that needs to determine a direct current converter station and a direct current power transmission line. The direct current converter station can include a rectifier station and an inverter station. The rectifier station can also be referred to as a sending-end converter station, that is, a converter station that converts alternating current into direct current. The inverter station can also be referred to as a receiving-end converter station, that is, a converter station that converts direct current into alternating current.

[0045] The converter station information can be information of the direct current converter station in the target direct current power transmission system, such as converter station distribution information, a number of converter stations and a converter station capacity, etc. The present application does not limit the converter station distribution information. The converter station distribution information can be location information of the converter station. The number of converter stations can be the number of converter stations in the target direct current power transmission system. The converter station capacity can be the maximum power that can be converted and transmitted by the converter station.

[0046] It can be understood that the direct current power transmission system can include a plurality of sending-end converter stations and a plurality of receiving-end converter stations. Each converter station in the direct current power transmission system can be connected with a node in an alternating current power transmission system.

[0047] In the embodiment of the present application, the determination method of the direct current power transmission system can first determine the converter station distribution information, the number of converter stations and the converter station capacity of the direct current converter station in the target direct current power transmission system.

[0048] S120, determining power transmission line information in the target direct current power transmission system based on a line planning model and according to the converter station information; wherein the power transmission line information includes a line connection scheme and a line capacity.

[0049] The line planning model can be a model for planning a DC transmission line in a DC transmission system. The transmission line information can be information of the DC transmission line in the target DC transmission system, such as a line connection scheme and a line capacity, and the like, which is not limited in the embodiments of the present application.

[0050] Specifically, the transmission line information can include information of the DC transmission line between the DC converter stations and information of the DC transmission line between the DC converter stations and the AC transmission system. The line connection scheme can be a connection scheme with the minimum sum of new line costs. The line capacity can be the maximum power that can be safely and stably transmitted by the DC transmission line under normal operating conditions.

[0051] In the embodiments of the present application, after the converter station information of the DC converter station in the target DC transmission system is determined, the transmission line information in the target DC transmission system can be further determined based on the line planning model according to the converter station information.

[0052] S130, at least one initial topology scheme of the DC converter station is determined according to the converter station information.

[0053] The initial topology scheme can be an initial topology scheme of the DC converter station. It can be understood that each DC converter station has a corresponding initial topology scheme, and the number of the initial topology schemes corresponding to the DC converter station can be one or more, which is not limited in the embodiments of the present application.

[0054] For example, assuming that the DC transmission system includes a DC converter station A and a DC converter station B, the initial topology scheme of the DC converter station A can have one, three or more, and the initial topology scheme of the DC converter station B can have one, five or more, which is not limited in the present application.

[0055] In the embodiments of the present application, after the converter station information of the DC converter station in the target DC transmission system is determined, the initial topology scheme of the DC converter station can be further determined according to the converter station information. Specifically, the initial topology scheme of the DC converter station can be determined according to the converter station distribution information and the converter station capacity in the converter station information.

[0056] S140, the initial topology schemes of the DC converter station are evaluated, and a target topology scheme is determined from the initial topology schemes according to the evaluation results.

[0057] The index evaluation can be an evaluation of whether the initial topology scheme meets the index condition. For example, the index condition can be one or more of a converter station power operating range index condition, an access point voltage support capability index condition, and a multi-DC interaction index condition, which is not limited in the embodiments of the present application.

[0058] The index evaluation result can be a result of whether the initial topology scheme satisfies the index condition. The target topology scheme can be one of the plurality of initial topology schemes of the DC converter station. It can be understood that each DC converter station corresponds to only one target topology scheme. Specifically, the initial topology schemes that do not satisfy the index condition can be excluded, and the initial topology schemes that satisfy the index condition can be retained.

[0059] In the embodiment of the present application, after the at least one initial topology scheme of the DC converter station is determined according to the converter station information, the index evaluation can be further performed on each initial topology scheme of the DC converter station, so as to determine the target topology scheme of the DC converter station in each initial topology scheme according to the index evaluation result.

[0060] It should be noted that, Figure 1 The steps S120 and S130-S140 do not have a sequence relationship, and the step S120 can be implemented first, and then the steps S130-S140 can be implemented. Alternatively, the steps S130-S140 can be implemented first, and then the step S120 can be implemented. Alternatively, the steps S120 and S130-S140 can be implemented synchronously.

[0061] S150, determining the target DC power transmission system according to the converter station information, the transmission line information and the target topology scheme.

[0062] In the embodiment of the present application, after the transmission line information in the target DC power transmission system is determined according to the converter station information, and the target topology scheme is determined in each initial topology scheme according to the index evaluation result, the target DC power transmission system can be further determined according to the converter station information, the transmission line information and the target topology scheme.

[0063] The technical scheme of the embodiment determines the converter station information of the DC converter station in the target DC power transmission system, and determines the transmission line information in the target DC power transmission system according to the converter station information based on the line planning model. Then, at least one initial topology scheme of the DC converter station is determined according to the converter station information, the index evaluation is performed on each initial topology scheme of the DC converter station, and the target topology scheme is determined in each initial topology scheme according to the index evaluation result. Finally, the target DC power transmission system is determined according to the converter station information, the transmission line information and the target topology scheme. Thus, the problem of poor stability, low reliability and poor economy of the existing DC power transmission system is solved, and the topology scheme of the safe and reliable DC converter station and the connection scheme of the transmission line with the lowest cost can be determined, so as to improve the safety, stability, reliability and economy of the DC power transmission system.

[0064] Embodiment two

[0065] Figure 2is a flow chart of a determination method of a direct current power transmission system provided by Embodiment Two of the present application, which is a further refinement of the above technical solutions and gives a plurality of specific optional implementation manners. The technical solution in this embodiment can be combined with each optional solution in one or more of the above embodiments. As shown in Figure 2 The method can include the following steps:

[0066] S210, determine the converter station distribution information and the number of converter stations in the target direct current power transmission system.

[0067] Optionally, the converter station distribution information can be determined according to the power source load distribution information and the grid power. Specifically, according to the power source load distribution, a sending-end converter station can be established at a grid power surplus place, and a receiving-end converter station can be established at a grid power shortage place, thereby determining the converter station distribution information.

[0068] It can be understood that after the converter station distribution information of the direct current converter station is determined, the number of converter stations can be determined according to the converter station distribution information.

[0069] S220, determine at least one target operation mode corresponding to the direct current converter station.

[0070] The target operation mode can be one or more of a plurality of operation modes of the grid. It can be understood that the grid has a plurality of operation modes, such as radial operation, ring network operation, island operation mode, unified dispatching operation, etc., and the present application does not limit this.

[0071] S230, determine the power value of the direct current converter station under each target operation mode; wherein the number of power values is consistent with the number of target operation modes.

[0072] The power value can be the absolute value of the power of the direct current converter station. The power of the direct current converter station can be the injection power of the converter station to the AC bus. It can be understood that the direct current converter station includes a sending-end converter station and a receiving-end converter station, and therefore the power of the direct current converter station has positive and negative, i.e. the power of the direct current converter station can be positive or negative.

[0073] It can be further understood that the operation mode and the power of the direct current converter station are one-to-one corresponding. The power of the direct current converter station can be different for different operation modes.

[0074] In the present embodiment, after the at least one target operation mode corresponding to the direct current converter station is determined, the power value of the direct current converter station under each target operation mode can be further determined. Specifically, the power of the direct current converter station under each target operation mode can be determined first, and then the absolute value of the power can be calculated according to the power of the direct current converter station under each target operation mode.

[0075] Optionally, if the number of DC converter stations connected with the AC bus is one, the power of the DC converter station in the target operation mode can be determined according to the following formula:

[0076]

[0077] wherein, Pik represents the power of the DC converter station i in the target operation mode k; Pik represents the power of the DC converter station i in the target operation mode k;

[0078] It can be understood that if the number of DC converter stations connected with the AC bus is one, the DC loss can be ignored, and it is considered that the DC reactive power is balanced locally, and the DC does not transmit the reactive power. That is, it can be understood that a pair of active power with equal size and opposite signs are injected into the AC bus of the sending and receiving end converter stations.

[0079] Optionally, if the number of DC converter stations connected with the AC bus is more than one, the power of the DC converter station in the target operation mode can be determined according to the following formula:

[0080]

[0081] wherein, Pik represents the power of the DC converter station i in the target operation mode k; Pik represents the power of the DC converter station i in the target operation mode k; Pik represents the power of the DC converter station i in the target operation mode k; wherein, j represents the number of DC converter stations; n1 represents the number of sending end converter stations; n2 represents the number of receiving end converter stations.

[0082] S240, determining the maximum value in the power values as the converter station capacity of the DC converter station.

[0083] Specifically, if the number of DC converter stations connected with the AC bus is one, the converter station capacity of the DC converter station can be determined based on the following formula:

[0084]

[0085] Specifically, if the number of DC converter stations connected with the AC bus is more than one, the converter station capacity of the DC converter station can be determined based on the following formula:

[0086]

[0087] wherein S st represents the converter station capacity of the direct current converter station; s represents the number of operation modes.

[0088] S250, based on the line planning model, determining, according to the converter station information, the power transmission line information in the target direct current power transmission system; wherein the power transmission line information comprises a line connection scheme and a line capacity.

[0089] Optionally, before determining, based on the line planning model, the power transmission line information in the target direct current power transmission system according to the converter station information, it can further comprise: constructing a target function with the sum of the new line costs in the target direct current power transmission system as the target; constructing a power conservation constraint condition according to the power data of the target line and the power data of the direct current converter station; wherein the target line is a power transmission line connected with the direct current converter station; constructing a capacity constraint condition according to the power data of the target line and the capacity data of the target line; constructing a sectional capacity constraint condition according to the sectional capacity data of the target line and the capacity data of the target line; constructing the line planning model according to the target function, the power conservation constraint condition, the capacity constraint condition and the sectional capacity constraint condition.

[0090] Specifically, the target function can be constructed based on the following formula:

[0091]

[0092] wherein F represents the sum of the new line costs in the target direct current power transmission system; n represents the number of the direct current power transmission lines ij between the direct current converter station i and the direct current converter station j, wherein j>i; F ij,0 represents the fixed cost of the first sectional line in the direct current power transmission line ij; y ij,1 represents the indicator variable of the first sectional line in the direct current power transmission line ij, the indicator variable being used to indicate whether the capacity of the first sectional line in the direct current power transmission line ij is zero; C ij,t represents the unit capacity cost corresponding to the t-th sectional line of the direct current power transmission line ij; S ij,t represents the capacity corresponding to the t-th sectional line of the direct current power transmission line ij; m represents the number of sections of the direct current power transmission line ij.

[0093] Specifically, assuming that there are n0 direct current converter stations, and a direct current power transmission line can be formed between any two converter stations, the number of the direct current power transmission lines ij can be n=n0(n0-1) / 2.

[0094] Specifically, y ij,t is an indicator variable, whose value is 0 or 1; y ij,t =1 indicates that the capacity of the t-th sectional line of the direct current power transmission line ij is not zero; y ij,t= 0 indicates that the capacity of the tth segment of the DC transmission line ij is zero.

[0095] It can be understood that the cost-capacity curve of each DC transmission line in the DC transmission system is known, and thus the cost-capacity curve of the DC transmission line can be linearly approximated in segments.

[0096] Exemplarily, Figure 3 is a schematic diagram of the cost-capacity curve of the DC transmission line provided by the second embodiment of the present application, as Figure 3 shown, the cost-capacity curve of the DC transmission line ij is divided into m segments, and then m+1 turning points (X ij,0 ,F ij,0 ), (X ij,1 ,F ij,1 ),..., (X ij,m ,F ij,m ) can be determined; wherein X represents the capacity and F represents the cost.

[0097] At this time, the capacity of the DC transmission line ij can be equal to the sum of the capacities of each segment, and the cost of the DC transmission line ij can be equal to the sum of the costs of each segment. For example, the capacity S' and the cost F' of the DC transmission line ij can be calculated based on the following formulas:

[0098] S' = S0y1 + S1 + S2 + S3

[0099] F' = F0y1 + C1S1 + C2S2 + C3S3

[0100] wherein S0 represents the minimum capacity of the DC transmission line ij; y1 represents whether the DC transmission line ij is a newly built line, y1 = 0 indicates that the DC transmission line ij is not a newly built line, and y1 = 1 indicates that the DC transmission line ij is a newly built line; S1, S2, S3 respectively represent the capacities of the three segments [X0, X1), [X1, X2), [X2, X3); F0 represents the fixed cost of the DC transmission line ij; C1, C2, C3 respectively represent the unit capacity cost of the three segments [X0, X1), [X1, X2), [X2, X3).

[0101] Specifically, the power conservation constraint condition can be constructed based on the following formula:

[0102]

[0103] wherein, represents the power of the DC converter station i in the operating mode k; represents the power of the DC transmission line ij in the operating mode k; Pij(k) represents the power of the DC transmission line ji in the operation mode k; A1 and A2 represent two sets of DC converter stations; S represents a set of operation modes.

[0104] Specifically, in a certain operation mode, if a DC converter station emits or absorbs power, the DC converter station can be added to set A1, and if the DC converter station does not emit or absorb power, the DC converter station can be regarded as a DC intermediate node, and at this time, the DC converter station can be added to set A2.

[0105] It should be noted that the power loss of each DC transmission line can be ignored.

[0106] Specifically, the capacity constraint condition can be constructed based on the following formula:

[0107]

[0108] wherein S ij represents the capacity of the DC transmission line ij.

[0109] It can be understood that the power of the DC transmission line in the target operation mode k is less than the capacity of the line.

[0110] Specifically, the capacity of the DC transmission line ij can be determined based on the following formula:

[0111]

[0112] Specifically, the piecewise capacity constraint condition can be constructed based on the following formula:

[0113]

[0114] It can be understood that if the first p y ij,t is 1, the first p-1 S ij,t =X ij,t -X ij,t-1 , and the pth S ij,t is between 0 and X ij,p -X ij,p-1 .

[0115] wherein the index variable satisfies the size relationship, and specifically can be determined based on the following formula:

[0116] 0≤y ij,m ≤y ij,m-1 ≤…≤y ij,t ≤…≤y ij,2 ≤y ij,1 ≤1

[0117] Optionally, based on the line planning model, the DC transmission line information in the target DC transmission system is determined according to the converter station information, which can include: determining the power of each DC converter station in different operation modes according to the converter station information; determining the cost-capacity curve of the possible routes between each DC converter station according to the converter station information; inputting the converter station distribution information, the number of converter stations, the power of each DC converter station in different operation modes and the cost-capacity curve of the possible routes into the line planning model; and the line planning model calculates the line connection scheme and the capacity of each DC transmission line with the minimum sum of new line costs based on the formula of the objective function and the constraint condition.

[0118] Specifically, when the line planning model is calculated based on the formula of the objective function and the constraint condition, various mainstream commercial solvers can be used for calculation, and the embodiments of the present application do not limit this.

[0119] S260, at least one initial topology scheme of the DC converter station is determined according to the converter station information.

[0120] It should be noted that the related processing procedure of "determining the initial topology scheme of the DC converter station according to the converter station information" can refer to the prior art, which will not be repeated here.

[0121] S270, the index evaluation of each initial topology scheme of the DC converter station is performed.

[0122] It can be understood that the typical converter station topology scheme can include LCC (grid commutated converter) and MMC (modular multilevel converter). In addition, with the development of power electronic technology, the converter station topology scheme can also include CCC (capacitive commutated converter), SLCC (multi-source adaptive commutated converter) and hybrid structure, and the present application does not limit this.

[0123] Optionally, the index evaluation includes converter station power operation range index evaluation; the index evaluation of each initial topology scheme of the DC converter station can include: determining the DC converter station of the initial topology scheme as a target converter station; determining the active power and reactive power of the target converter station; determining the power operation range corresponding to the target converter station according to the active power and reactive power of the target converter station; if the power demand of the target converter station is within the power operation range, it is determined that the initial topology scheme meets the converter station power operation range index evaluation; wherein the power demand of the target converter station includes the power demand of the target converter station in all target operation modes.

[0124] Exemplarily, Figure 4 is a schematic diagram of a two-dimensional plane provided by the second embodiment of the present application, as Figure 4As shown, the power operating range of the target converter station can be represented as a closed region (e.g., the shaded part) of a two-dimensional plane. Specifically, the power operating range of the target converter station can be determined based on the following formula:

[0125] f = f (P st , Q st )

[0126] wherein f represents the power operating range of the target converter station; P st represents the active power of the target converter station; and Q st represents the reactive power of the target converter station.

[0127] Specifically, each target converter station can correspond to multiple operating modes. When the power demand of the target converter station under all operating modes is within the power operating range, it can be determined that the initial topology scheme corresponding to the target converter station satisfies the converter station power operating range index evaluation. That is, if the power demand of the target converter station under any operating mode is not within the power operating range, it can be determined that the initial topology scheme corresponding to the target converter station does not satisfy the converter station power operating range index evaluation.

[0128] Specifically, the initial topology scheme of the DC converter station can be one or more. When there are multiple initial topology schemes of the DC converter station, it can be determined in turn whether each initial topology scheme of the DC converter station satisfies the converter station power operating range index evaluation.

[0129] Optionally, the index evaluation includes access point voltage support capability index evaluation. The index evaluation on each initial topology scheme of the DC converter station can include: when the DC converter station is a newly-built converter station, determining the DC converter station of the initial topology scheme as a target converter station; determining the no-load voltage and the access voltage of the grid access point; wherein the no-load voltage is the voltage of the grid access point before the target converter station accesses the grid; the access voltage is the voltage of the grid access point after the target converter station accesses the grid under the target operating mode; calculating the voltage support strength of the grid access point corresponding to the target operating mode according to the no-load voltage and the access voltage of the grid access point; and if the voltage support strength of the grid access point corresponding to all target operating modes is greater than the voltage support strength threshold, determining that the initial topology scheme satisfies the access point voltage support capability index evaluation.

[0130] wherein the grid access point can be any access point in the grid.

[0131] Specifically, the voltage support strength of the grid access point corresponding to the target operating mode can be calculated according to the no-load voltage and the access voltage of the grid access point based on the following formula:

[0132]

[0133] wherein, K vtg represents the voltage support strength of the grid access point, i.e. the ability to maintain the access point voltage magnitude close to the no-load voltage of the access point; U sys represents the access voltage of the grid access point; U sys0 represents the no-load voltage of the grid access point; Z dc represents the DC equivalent impedance, Z th represents the Thevenin equivalent impedance, λ SCR represents the short circuit ratio.

[0134] It can be understood that, under the fundamental positive sequence network, according to the Thevenin equivalent principle, the entire grid can be represented by a Thevenin equivalent circuit from any point SYS in the grid to the grid.

[0135] Exemplarily, Figure 5 is a schematic diagram of a Thevenin equivalent circuit provided by Embodiment Two of the present application, as Figure 5 shown, the Thevenin equivalent potential E th is equal to the no-load voltage at point SYS when the DC is not connected to the grid Thevenin equivalent impedance Z th is equal to the equivalent impedance from point SYS to the network when each independent power supply in the fundamental positive sequence network is set to zero. It can be understood that the DC equivalent impedance is different when different converter station topologies are adopted.

[0136] Specifically, when the voltage support strength of the grid access point corresponding to each operating mode of the target converter station is greater than the voltage support strength threshold, it can be determined that the initial topology scheme corresponding to the target converter station satisfies the access point voltage support capability index evaluation. That is, if the voltage support strength of the grid access point corresponding to any one operating mode of the target converter station is less than the voltage support strength threshold, it can be determined that the initial topology scheme corresponding to the target converter station does not satisfy the access point voltage support capability index evaluation.

[0137] It should be noted that the voltage support strength threshold can be determined according to actual requirements or experience values, and the specific value of the voltage support strength threshold is not limited in the present application.

[0138] Specifically, the initial topology scheme of the DC converter station can have one or more, and when the initial topology scheme of the DC converter station has multiple, it can be determined in turn whether each initial topology scheme of the DC converter station satisfies the access point voltage support capability index evaluation.

[0139] Optionally, the index evaluation includes multi-direct-current interaction index evaluation; the index evaluation on each initial topology scheme of the direct-current converter station can include: when the direct-current converter station is a newly-built converter station, determining the direct-current converter station of the initial topology scheme as a target converter station; determining a target alternating-current system connected with the target converter station; determining a target existing line connected with the target alternating-current system before the target converter station is connected to the power grid; determining a first voltage stiffness and a second voltage stiffness of the target existing line; wherein the first voltage stiffness is a voltage stiffness of the target existing line before the target converter station is connected to the power grid; the second voltage stiffness is a voltage stiffness of the target existing line after the target converter station is connected to the power grid under a target operating mode; calculating a multi-direct-current feeding no-load voltage drop factor of the target existing line corresponding to the target operating mode according to the first voltage stiffness and the second voltage stiffness of the target existing line; if the multi-direct-current feeding no-load voltage drop factors of the target existing line corresponding to all the target operating modes are all less than a drop factor threshold, it is determined that the initial topology scheme meets the multi-direct-current interaction index evaluation.

[0140] It can be understood that, in the multi-feed direct-current system, in addition to paying attention to the influence of the characteristics of the direct-current converter station itself on the voltage stability of the system, the influence of the interaction between the direct-current converter stations on the voltage stability of the system also needs to be paid attention to.

[0141] Exemplarily, Figure 6 is a schematic diagram of another Thevenin equivalent circuit provided by the second embodiment of the present application, as shown in Figure 6 The equivalent circuit of the double-direct-current feeding alternating-current power grid can be obtained according to the Thevenin equivalence principle of the two-port network, as shown in the double-direct-current feeding alternating-current power grid. E th and the Thevenin equivalent impedance Z th , then the Thevenin equivalent potential from the bus i to the power grid when the direct-current line j is connected to the power grid is and the Thevenin equivalent impedance , that is, the ratio of the Thevenin equivalent potential from the bus i to the power grid under the two conditions of before and after the multi-direct-current feeding. Thus, the following calculation formula can be obtained:

[0142]

[0143] wherein, U io represents the no-load voltage phase of the bus i under the condition of no multi-direct-current feeding; represents the no-load voltage phase of the bus i under the condition of multi-direct-current feeding; is the ratio of the Thevenin equivalent impedance from the bus i to the power grid under the two conditions of before and after the multi-direct-current feeding; a target existing line, that is, a target existing line multi-direct-current feed-in no-load voltage drop factor under a target existing line voltage; a second voltage stiffness of a target existing line; K vtg a first voltage stiffness of a target existing line.

[0144] Specifically, based on the above calculation formula, the following formula of the target existing line multi-direct-current feed-in no-load voltage drop factor can be determined, that is, according to the first voltage stiffness and the second voltage stiffness of the target existing line, the target existing line multi-direct-current feed-in no-load voltage drop factor corresponding to the target operating mode is calculated, which can be determined based on the following formula:

[0145]

[0146] Specifically, when the target existing line multi-direct-current feed-in no-load voltage drop factor corresponding to different operating modes of the target converter station is all less than the drop factor threshold, it can be determined that the initial topology scheme corresponding to the target converter station satisfies the multi-direct-current interaction index evaluation. That is, if the target existing line multi-direct-current feed-in no-load voltage drop factor corresponding to any one operating mode of the target converter station is greater than the drop factor threshold, it can be determined that the initial topology scheme corresponding to the target converter station does not satisfy the multi-direct-current interaction index evaluation.

[0147] It should be noted that the drop factor threshold can be determined according to actual demand or experience value, and the specific value of the drop factor threshold is not limited in the embodiment of the present application.

[0148] Specifically, the initial topology scheme of the direct-current converter station can have one or more, and when the initial topology scheme of the direct-current converter station has multiple, whether each initial topology scheme of the direct-current converter station satisfies the multi-direct-current interaction index evaluation can be determined in turn.

[0149] S280, if the initial topology scheme satisfies the index evaluation, the converter station cost of the direct-current converter station of the initial topology scheme is calculated.

[0150] Specifically, if the initial topology scheme satisfies the index evaluation, the converter station cost of the direct-current converter station of the initial topology scheme can be calculated when the initial topology scheme satisfies all the index evaluations.

[0151] It can be understood that there can be multiple initial topology schemes satisfying the index evaluation, and then the converter station cost of the direct-current converter station of all the initial topology schemes satisfying the index evaluation can be calculated.

[0152] Specifically, the converter station cost can include investment construction and operation and maintenance loss fees. The investment construction fee can be represented as a product of unit capacity cost and capacity, and the operation and maintenance loss fee is divided into operation and maintenance fee and loss fee. The annual operation and maintenance fee is proportional to the initial investment construction fee, and the annual loss fee can be represented as a product of the on-grid electricity price and the loss electricity quantity, and each year's operation and maintenance loss fee needs to be converted into present value.

[0153] Specifically, the converter station cost of the direct current converter station in the initial topology scheme can be calculated based on the following formula:

[0154] C st =C st1 +k a *C st2

[0155] C st1 =k c S st

[0156] C st2 =(k m C st1 +k l S st τC p )

[0157]

[0158] Wherein, C st represents the converter station cost of the direct current converter station; C st1 represents the investment construction fee of the direct current converter station; C st2 represents the operation and maintenance loss fee of the direct current converter station; k a represents the discount rate; k c represents the unit capacity cost of the direct current converter station; S st represents the capacity of the direct current converter station; k m represents the maintenance fee coefficient; k l represents the loss fee coefficient; τ is the annual operating hours, C p is the on-grid electricity price, I is the annual interest rate of funds, and N is the operation time.

[0159] S290, determine the initial topology scheme with the minimum converter station cost as the target topology scheme.

[0160] S2100, determine the target direct current power transmission system according to the converter station information, the power transmission line information and the target topology scheme.

[0161] The technical scheme of the embodiment determines the converter station distribution information and the number of converter stations in the target DC power transmission system, determines at least one target operation mode corresponding to the DC converter station, determines the power values of the DC converter station under each target operation mode, and determines the maximum value of each power value as the converter station capacity of the DC converter station. The line planning model is used to determine the transmission line information in the target DC power transmission system based on the converter station information, to determine at least one initial topology scheme of the DC converter station based on the converter station information, to perform index evaluation on each initial topology scheme of the DC converter station, to calculate the converter station cost of the initial topology scheme if the initial topology scheme meets the index evaluation, and to determine the initial topology scheme with the minimum converter station cost as the target topology scheme. Thus, the target DC power transmission system is determined based on the converter station information, the transmission line information and the target topology scheme, thereby solving the problems of poor stability, low reliability and poor economy of the existing DC power transmission system, and determining a safe and reliable topology scheme of the DC converter station and a connection scheme of the transmission line with the lowest cost, thereby improving the safety, stability, reliability and economy of the DC power transmission system.

[0162] Embodiment three

[0163] Figure 7 is a schematic diagram of a determination device of a DC power transmission system provided by the embodiment three, as shown in the figure, the device comprises a converter station information determination module 710, a line information determination module 720, an initial topology scheme determination module 730, a target topology scheme determination module 740 and a target DC power transmission system determination module 750, wherein: Figure 7

[0164] The converter station information determination module 710 is configured to determine the converter station information of the DC converter station in the target DC power transmission system, wherein the converter station information comprises converter station distribution information, the number of converter stations and the converter station capacity.

[0165] The line information determination module 720 is configured to determine the transmission line information in the target DC power transmission system based on the line planning model and the converter station information, wherein the transmission line information comprises a line connection scheme and a line capacity.

[0166] The initial topology scheme determination module 730 is configured to determine at least one initial topology scheme of the DC converter station based on the converter station information.

[0167] The target topology scheme determination module 740 is configured to perform index evaluation on each initial topology scheme of the DC converter station, and determine the target topology scheme from the initial topology schemes based on the index evaluation result.

[0168] ​The target DC power transmission system determination module 750 is configured to determine the target DC power transmission system according to the converter station information, the transmission line information, and the target topology scheme.

[0169] The technical scheme of the embodiment determines the converter station information of the DC converter station in the target DC power transmission system, determines the transmission line information in the target DC power transmission system based on the line planning model according to the converter station information, determines at least one initial topology scheme of the DC converter station according to the converter station information, performs index evaluation on each initial topology scheme of the DC converter station, and determines the target topology scheme from the initial topology schemes according to the index evaluation result, so as to determine the target DC power transmission system according to the converter station information, the transmission line information, and the target topology scheme. The technical scheme solves the problems of poor stability, low reliability, and poor economy of the existing DC power transmission system, can determine a safe and reliable topology scheme of the DC converter station and a connection scheme of the transmission line with the lowest cost, and improves the safety, stability, reliability, and economy of the DC power transmission system.

[0170] Optionally, the converter station information determination module 710 can be specifically configured to determine at least one target operation mode corresponding to the DC converter station, determine power values of the DC converter station in each target operation mode, wherein the number of the power values is consistent with the number of the target operation modes, and determine a maximum value in the power values as the converter station capacity of the DC converter station.

[0171] Optionally, the line information determination module 720 can be specifically configured to, before determining the transmission line information in the target DC power transmission system according to the converter station information based on the line planning model, construct a target function with the minimum sum of the new line costs in the target DC power transmission system as the target, construct a power conservation constraint condition according to the power data of the target line and the power data of the DC converter station, wherein the target line is the transmission line connected to the DC converter station, construct a capacity constraint condition according to the power data of the target line and the capacity data of the target line, construct a sectional capacity constraint condition according to the sectional capacity data of the target line and the capacity data of the target line, and construct the line planning model according to the target function, the power conservation constraint condition, the capacity constraint condition, and the sectional capacity constraint condition.

[0172] Optionally, the index evaluation includes a power operation range index evaluation of the converter station; the target topology scheme determination module 740 can be specifically configured to: determine the DC converter station in the initial topology scheme as a target converter station; determine active power and reactive power of the target converter station; determine a power operation range corresponding to the target converter station according to the active power and the reactive power of the target converter station; if the power demand of the target converter station is within the power operation range, determine that the initial topology scheme satisfies the power operation range index evaluation of the converter station; wherein the power demand of the target converter station includes the power demand of the target converter station in all target operation modes.

[0173] Optionally, the index evaluation further includes an access point voltage support capability index evaluation; the target topology scheme determination module 740 can be specifically configured to: when the DC converter station is a newly-built converter station, determine the DC converter station in the initial topology scheme as a target converter station; determine a no-load voltage and an access voltage of a power grid access point; wherein the no-load voltage is the voltage of the power grid access point before the target converter station accesses the power grid; the access voltage is the voltage of the power grid access point after the target converter station accesses the power grid in the target operation mode; calculate voltage support strength of the power grid access point corresponding to the target operation mode according to the no-load voltage and the access voltage of the power grid access point; if the voltage support strength of the power grid access point corresponding to all target operation modes is greater than a voltage support strength threshold, determine that the initial topology scheme satisfies the access point voltage support capability index evaluation.

[0174] Optionally, the index evaluation further includes a multi-DC interaction index evaluation; the target topology scheme determination module 740 can be specifically configured to: when the DC converter station is a newly-built converter station, determine the DC converter station in the initial topology scheme as a target converter station; determine a target AC system connected to the target converter station; determine a target existing line connected to the target AC system before the target converter station accesses the power grid; determine a first voltage stiffness and a second voltage stiffness of the target existing line; wherein the first voltage stiffness is the voltage stiffness of the target existing line before the target converter station accesses the power grid; the second voltage stiffness is the voltage stiffness of the target existing line after the target converter station accesses the power grid in the target operation mode; calculate a multi-DC feeding no-load voltage drop factor of the target existing line corresponding to the target operation mode according to the first voltage stiffness and the second voltage stiffness of the target existing line; if the multi-DC feeding no-load voltage drop factor of the target existing line corresponding to all target operation modes is less than a drop factor threshold, determine that the initial topology scheme satisfies the multi-DC interaction index evaluation.

[0175] Optionally, the target topology scheme determination module 740 can be further configured to: if the initial topology scheme satisfies the index evaluation, calculate a converter station cost of the DC converter station in the initial topology scheme; determine the initial topology scheme with the minimum converter station cost as the target topology scheme.

[0176] The determination device of the DC power transmission system provided by the embodiment of the present application can execute the determination method of the DC power transmission system provided by any of the embodiments of the present application, and has the function modules and beneficial effects corresponding to the execution method.

[0177] Embodiment Four

[0178] Figure 8 A structural schematic diagram of an electronic device 10 that can be used to implement embodiments of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptops, desktops, tablets, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular telephones, smart phones, wearable devices (e.g., headsets, glasses, watches, etc.), and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not intended to limit the implementations of the present application described and / or claimed in this document.

[0179] As Figure 8 shown, the electronic device 10 includes at least one processor 11, and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., which is communicatively connected to the at least one processor 11, wherein the memory stores a computer program that can be executed by the at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or loaded into the random access memory (RAM) 13 from the storage unit 18. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0180] Various components in the electronic device 10 are connected to the I / O interface 15, including an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, a speaker, etc.; a storage unit 18, such as a magnetic disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network, such as the Internet, and / or various telecommunication networks.

[0181] The processor 11 can be various general and / or special purpose processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 performs various methods and processes described above, such as the determination method of the direct current power transmission system.

[0182] In some embodiments, the determination method of the direct current power transmission system can be implemented as a computer program tangibly embodied in a computer readable storage medium, such as the storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed onto the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded onto the RAM 13 and executed by the processor 11, one or more steps of the determination method of the direct current power transmission system described above can be performed. Alternatively, in other embodiments, the processor 11 can be configured to perform the determination method of the direct current power transmission system by any other suitable means, such as by means of firmware.

[0183] Various implementations of the systems and techniques described above can be realized in digital electronic circuitry, integrated circuitry, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on a chip (SOC), a programmable logic device (PLD), a computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0184] Computer programs used to implement the methods of the application can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the computer program, when executed, implements the functions / acts specified in the flowcharts and / or block diagrams. The computer program can be executed entirely on a machine, partially on a machine, partially on a machine as a stand-alone software package, partially on a machine and partially on a remote machine or entirely on a remote machine or server.

[0185] In the context of the present application, a computer-readable storage medium can be a tangible medium that can contain or store computer programs for use by or in connection with an instruction execution system, apparatus, or device. Computer-readable storage media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of a machine-readable storage medium will include one or more lines of a program of instructions in a transitory signal, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0186] To provide for interaction with a user, the systems and techniques described here can be implemented on an electronic device having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0187] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0188] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system, to solve the defects of large management difficulty and weak business scalability in traditional physical host and VPS service.

[0189] It should be understood that the various forms of flow shown above can be reordered, added to, or have steps deleted. For example, the steps described in the present application can be performed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, and this is not limited herein.

[0190] The above detailed description does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining a DC transmission system, characterized in that, include: Determine the converter station information of the DC converter stations in the target DC transmission system; wherein, the converter station information includes converter station distribution information, number of converter stations, and converter station capacity; Based on the line planning model and the converter station information, the transmission line information in the target DC transmission system is determined; wherein, the transmission line information includes the line connection scheme and the line capacity; Based on the converter station information, at least one initial topology scheme for the DC converter station is determined; The initial topology schemes of the DC converter station are evaluated for their performance indicators. Based on the evaluation results, a target topology scheme is determined from the initial topology schemes. The target DC transmission system is determined based on the converter station information, the transmission line information, and the target topology scheme.

2. The method according to claim 1, characterized in that, Determine the converter station capacity of the DC converter stations in the target DC transmission system, including: Determine at least one target operating mode corresponding to the DC converter station; Determine the power values ​​of the DC converter station under each of the target operating modes; wherein the number of power values ​​is consistent with the number of target operating modes; The maximum value among the power values ​​is determined as the converter station capacity of the DC converter station.

3. The method according to claim 1, characterized in that, Before determining the transmission line information in the target DC transmission system based on the converter station information using the line planning model, the method further includes: An objective function is constructed with the goal of minimizing the total cost of newly constructed lines in the target DC transmission system. Based on the power data of the target line and the power data of the DC converter station, power conservation constraints are constructed; wherein, the target line is the transmission line connected to the DC converter station. Based on the power data and capacity data of the target line, capacity constraints are constructed. Based on the segmented capacity data and the total capacity data of the target line, segmented capacity constraints are constructed. The line planning model is constructed based on the objective function, the power conservation constraint, the capacity constraint, and the segmented capacity constraint.

4. The method according to claim 2, characterized in that, The evaluation of the indicators includes the evaluation of the converter station's power operating range. The evaluation of the performance indicators for each of the initial topology schemes of the DC converter station includes: The DC converter station in the initial topology scheme is identified as the target converter station; Determine the active power and reactive power of the target converter station; Based on the active and reactive power of the target converter station, determine the power operating range corresponding to the target converter station; If the power requirement of the target converter station is within the power operating range, the initial topology scheme is determined to meet the power operating range index evaluation of the converter station; The power requirements of the target converter station include the power requirements of the target converter station under all target operating modes.

5. The method according to claim 4, characterized in that, The evaluation of the indicators also includes the evaluation of the access point voltage support capability indicator; The evaluation of the performance indicators for each of the initial topology schemes of the DC converter station includes: When the DC converter station is a newly built converter station, the DC converter station in the initial topology scheme is determined as the target converter station; Determine the no-load voltage and the access voltage at the grid connection point; wherein, the no-load voltage is the voltage at the grid connection point before the target converter station is connected to the grid; and the access voltage is the voltage at the grid connection point after the target converter station is connected to the grid under the target operating mode. Based on the no-load voltage and access voltage of the power grid connection point, calculate the voltage support strength of the power grid connection point corresponding to the target operating mode; If the voltage support strength of the grid access point corresponding to all target operating modes is greater than the voltage support strength threshold, the initial topology scheme is determined to meet the voltage support capability index assessment of the access point.

6. The method according to claim 5, characterized in that, The evaluation of indicators also includes the evaluation of multiple DC interaction indicators. The evaluation of the performance indicators for each of the initial topology schemes of the DC converter station includes: When the DC converter station is a newly built converter station, the DC converter station in the initial topology scheme is determined as the target converter station; Identify the target AC system connected to the target converter station; Identify the existing lines connected to the target AC system before the target converter station is connected to the power grid; Determine the first voltage stiffness and the second voltage stiffness of the target existing line; wherein, the first voltage stiffness is the voltage stiffness of the target existing line before the target converter station is connected to the grid; and the second voltage stiffness is the voltage stiffness of the target existing line after the target converter station is connected to the grid under the target operating mode. Based on the first voltage stiffness and the second voltage stiffness of the target existing line, calculate the multi-DC feed-in no-load voltage drop factor of the target existing line corresponding to the target operating mode. If the no-load voltage drop factor of the multi-DC feeder for all target operating modes is less than the drop factor threshold, the initial topology scheme is determined to meet the multi-DC interaction index evaluation.

7. The method according to any one of claims 1, 4, 5 and 6, characterized in that, The step of determining the target topology scheme from each of the initial topology schemes based on the index evaluation results includes: If the initial topology scheme meets the evaluation criteria, calculate the converter station cost of the DC converter station in the initial topology scheme; The initial topology scheme with the lowest converter station cost is determined as the target topology scheme.

8. A device for determining a DC transmission system, characterized in that, include: The converter station information determination module is used to determine the converter station information of DC converter stations in the target DC transmission system; wherein, the converter station information includes converter station distribution information, number of converter stations, and converter station capacity; The line information determination module is used to determine the transmission line information in the target DC transmission system based on the line planning model and the converter station information; wherein, the transmission line information includes the line connection scheme and the line capacity; An initial topology scheme determination module is used to determine at least one initial topology scheme for the DC converter station based on the converter station information. The target topology scheme determination module is used to evaluate the indicators of each of the initial topology schemes of the DC converter station, and determine the target topology scheme from each of the initial topology schemes based on the evaluation results. The target DC transmission system determination module is used to determine the target DC transmission system based on the converter station information, the transmission line information, and the target topology scheme of the DC converter station.

9. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor to enable the at least one processor to perform the method for determining a DC transmission system according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the method for determining the DC transmission system according to any one of claims 1-7.

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