Direct-current converter station planning method and device for extra-high-voltage alternating-current and direct-current hybrid power grid

Abstract

The invention relates to the technical field of direct-current converter station planning, and particularly provides a direct-current converter station planning method and device for an extra-high-voltage alternating-current and direct-current hybrid power grid, and the method comprises the steps: carrying out the system partitioning of a to-be-planned power grid based on a multi-infeed direct-current interaction influence factor between nodes in the to-be-planned power grid; generating a plurality of system partition alternative drop point schemes based on the node features in each system partition and a pre-constructed alternative drop point region planning model; respectively determining comprehensive evaluation values of the alternative drop point schemes of the plurality of system partitions in a converter station planning evaluation index system; and selecting the system partition alternative drop point scheme with the highest comprehensive evaluation value as a system partition drop point scheme. The technical scheme provided by the invention is simple and easy to implement, and is beneficial to engineering practice.

Description

Technical Field

[0001] The present invention relates to the technical field of DC converter station planning, and specifically to a method and device for planning a DC converter station in a UHV AC / DC hybrid power grid. Background Art

[0002] The advantages of high-voltage DC technology in large-scale power supply have promoted its application in cross-regional power transmission, especially in the optimal allocation of renewable energy. In the receiving-end power grid with multiple DC feeders, the coupling between the AC / DC system and between different DC lines poses severe challenges to the security and stability of the power system.

[0003] The problem of locating high-voltage DC converter stations is a complex decision-making problem in the power system, which requires comprehensive consideration of decision-making objectives, system security, operation economy, and project implementation difficulty. At present, the site selection optimization methods mainly draw on methods such as substation site selection, site selection of medium-voltage flexible DC ring network control devices, and DC drop point selection. Usually, according to the power transmission and reception relationship of the power system, planners directly formulate a series of DC drop point schemes. On this basis, indicators such as system security, stability, and economy are calculated, and then analyzed and evaluated. Through the comparison of the results, the final DC drop point scheme is determined. At present, there is little research on the planning method of high-voltage DC converter stations in power grids with a high proportion of new energy, and the evaluation index system is relatively single. Therefore, it is of great significance to study in detail the preliminary scheme screening strategy for locating high-voltage DC converter stations under the new power grid and to propose a more perfect evaluation index system for converter station site selection. Summary of the Invention

[0004] In order to overcome the above defects, the present invention proposes a method and device for planning a DC converter station in a UHV AC / DC hybrid power grid.

[0005] In a first aspect, a method for planning a DC converter station in a UHV AC / DC hybrid power grid is provided. The method for planning a DC converter station in a UHV AC / DC hybrid power grid includes:

[0006] Systematically partitioning the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned;

[0007] Generating multiple alternative drop point schemes for each system partition based on the node characteristics in each system partition and a pre-constructed alternative drop point area planning model;

[0008] Respectively determining the comprehensive evaluation values of the multiple alternative drop point schemes for each system partition in the converter station planning evaluation index system;

[0009] Selecting the alternative drop point scheme for the system partition with the highest comprehensive evaluation value as the drop point scheme for the system partition.

[0010] Preferably, the system partitioning of the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned includes:

[0011] Determining the interaction influence index between nodes in the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned;

[0012] Taking the interaction influence index between nodes in the power grid to be planned as a reference, performing clustering using the k-means algorithm;

[0013] Dividing the nodes in the same clustering cluster in the clustering result into a system partition.

[0014] Further, the multi-infeed DC interaction influence factors between nodes in the power grid to be planned are as follows:

[0015]

[0016] In the above formula, MIIF ji is the multi-infeed DC interaction influence factor between node j and node i, △U j is the voltage change of node j, △U i is the voltage change of node i, Z eqji is the equivalent reactance between node j and node i, Z eqii is the equivalent self-impedance of node i.

[0017] Further, the interaction influence index between nodes in the power grid to be planned is as follows:

[0018]

[0019] In the above formula, B ij is the interaction influence index between node i and node j, B ji is the interaction influence index between node j and node i, MIIF ij is the multi-infeed DC interaction influence factor between node i and node j.

[0020] Preferably, generating multiple alternative landing point schemes for system partitions based on the node characteristics in each system partition and a pre-constructed alternative landing point area planning model includes:

[0021] Step 1 Initialize the number of iterations;

[0022] Step 2 Substitute the node characteristics in each system partition into the pre-constructed alternative landing point area planning model and solve to obtain the optimization result, and use the optimization result as the alternative landing point scheme for the system partition;

[0023] Judge whether the preset number of iterations is reached. If so, output all alternative landing point schemes for system partitions. Otherwise, increment the number of iterations by 1 and return to Step 2;

[0024] Among them, the optimization results include at least one of the following: the number of high-voltage direct current (HVDC) converter stations in the system, the number of HVDC converter stations planned for each system partition, and the HVDC converter station planning coefficient of each node in each system partition. The node characteristics include at least one of the following: voltage, power, active load, and reactive load.

[0025] Furthermore, the pre-constructed alternative landing area planning model includes an objective function aiming at the optimal economy and its corresponding constraint conditions.

[0026] Furthermore, the objective function is as follows:

[0027]

[0028] In the above formula, f is the objective value, N l is the number of branches in the system, G ij is the conductance of branch ij, U i is the voltage of node i, U j is the voltage of node j, θ ij is the phase angle of branch ij, N C is the number of HVDC converter stations in the system, η c is the conversion efficiency of HVDC converter station c, P c is the active power of HVDC converter station c, i, j ∈ [1, N], and N is the number of nodes in the system.

[0029] Furthermore, the constraint conditions are as follows:

[0030]

[0031] P Gi,min ≤ P Gi ≤ P Gi,max

[0032] Q Gi,min ≤ Q Gi ≤ Q Gi,max

[0033] P Wi,min ≤ P Wi ≤ P Wi,max

[0034] U i,min ≤ U i ≤ U i,max

[0035] P ij,min ≤ P ij ≤ P ij,max

[0036] In the above formula, PGi is the active power output of the generator at node i, P Wi is the active power output of the wind turbine at node i, σ i is the HVDC converter station planning coefficient at node i. If an HVDC converter station is established at node i, then σ i = 1; otherwise, σ i = 0, P Li is the active power load at node i, b ij is the susceptance of branch ij, Q Gi is the reactive power output of the generator at node i, Q Li is the active power load at node i, P Gi,min is the minimum value of the active power output of the generator at node i, P Gi,max is the maximum value of the active power output of the generator at node i, Q Gi,min is the minimum value of the reactive power output of the generator at node i, Q Gi,max is the maximum value of the reactive power output of the generator at node i, P Wi,min is the minimum value of the wind turbine output at node i, P Wi,max is the maximum value of the wind turbine output at node i, U i,min is the minimum value of the node voltage at node i, U i,max is the maximum value of the node voltage at node i, P ij,min is the minimum value of the active power that can be transmitted through branch ij, P ij is the active power that can be transmitted through branch ij, P ij,max is the maximum value of the active power that can be transmitted through branch ij.

[0037] Furthermore, the constraint conditions are as follows:

[0038]

[0039] SCR i ≥ σ i SCR min

[0040] In the above formula, N bn is the number of nodes in system partition n, a n is the number of HVDC converter stations planned in system partition n, SCR i is the short-circuit ratio of node i, SCR min is the minimum short-circuit ratio.

[0041] Preferably, determining the comprehensive evaluation values of the multiple system partition alternative landing point schemes in the converter station planning evaluation index system includes:

[0042] Determining the index values of each terminal index of the system partition alternative landing point scheme s in the converter station planning evaluation index system;

[0043] Determine the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system based on the index values of each sub-index in the converter station planning evaluation index system and the weights corresponding to each sub-index.

[0044] Furthermore, the converter station planning evaluation index system is a secondary index system, the primary index is the comprehensive evaluation value, and the secondary indexes include: economic index, integrity index, balance index, minimum multi-infeed short-circuit ratio index, and stability index.

[0045] Furthermore, the economic index I eco (s) of the system partition alternative landing point scheme s in the converter station planning evaluation index system is calculated as follows:

[0046] I eco (s) = f s

[0047] The integrity index I whole (s) of the system partition alternative landing point scheme s in the converter station planning evaluation index system is calculated as follows:

[0048]

[0049] The balance index I balance (s) of the system partition alternative landing point scheme s in the converter station planning evaluation index system is calculated as follows:

[0050]

[0051] The minimum multi-infeed short-circuit ratio index I scr (s) of the system partition alternative landing point scheme s in the converter station planning evaluation index system is calculated as follows:

[0052] I scr (s) = min{MISCR sc , s = 1, 2,..., m, c = 1, 2,..., N C}

[0053] The stability index I lfd (s) of the system partition alternative landing point scheme s in the converter station planning evaluation index system is calculated as follows:

[0054]

[0055] In the above formula, f s is the active power loss of the high-voltage DC converter station under the system partition alternative landing point scheme s, RK scis the risk resistance coefficient of the node at the high-voltage DC converter station c under the system partition alternative landing point scheme s, m is the number of system partition alternative landing point schemes, MISCR sc is the multi-infeed DC short-circuit ratio of the node at the high-voltage DC converter station c under the system partition alternative landing point scheme s, N C is the number of high-voltage DC converter stations in the system, N l is the number of branches in the system, S ftmax is the maximum apparent power of the branch ft, S s,ft is the actual transmission power of the branch ft under the system partition alternative landing point scheme s.

[0056] Furthermore, the risk resistance coefficient of the node at the high-voltage DC converter station c under the system partition alternative landing point scheme s is as follows:

[0057]

[0058] In the above formula, MIIF ic is the multi-infeed DC interaction influence factor between node i and node c, and N is the number of nodes in the system.

[0059] Furthermore, the multi-infeed DC short-circuit ratio of the node at the high-voltage DC converter station c under the system partition alternative landing point scheme s is as follows:

[0060]

[0061] In the above formula, P dci is the DC power fed into node i, S aci is the short-circuit capacity at node i, MIIF ci is the multi-infeed DC interaction influence factor between node c and node i, P dc is the DC power fed into node c.

[0062] Furthermore, the weights corresponding to the respective final-level indicators are as follows:

[0063]

[0064] In the above formula, ω k is the weight corresponding to the final-level indicator k, λ k is the weight corresponding to the final-level indicator k obtained by the analytic hierarchy process, a k is the weight corresponding to the final-level indicator k obtained by the entropy weight method, and q is the number of final-level indicators.

[0065] Furthermore, determining the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system based on the index values of the respective final-level indicators and the weights corresponding to the respective final-level indicators under the system partition alternative landing point scheme s includes:

[0066] Based on the index values of each sub - index in the converter station planning evaluation index system for the alternative system partition landing point scheme s and the weights corresponding to each sub - index, the TOPSIS algorithm is used to determine the comprehensive evaluation value of the alternative system partition landing point scheme s in the converter station planning evaluation index system.

[0067] In a second aspect, a direct - current converter station planning device for a UHV AC - DC hybrid power grid is provided. The direct - current converter station planning device for the UHV AC - DC hybrid power grid includes:

[0068] A partitioning module, configured to partition the power grid to be planned based on the multi - infeed DC interaction influence factors between nodes in the power grid to be planned;

[0069] An analysis module, configured to generate multiple alternative system partition landing point schemes based on the node characteristics in each system partition and a pre - constructed alternative landing area planning model;

[0070] An evaluation module, configured to respectively determine the comprehensive evaluation values of the multiple alternative system partition landing point schemes in the converter station planning evaluation index system;

[0071] A screening module, configured to select the alternative system partition landing point scheme with the highest comprehensive evaluation value as the system partition landing point scheme.

[0072] In a third aspect, a computer device is provided, including: one or more processors;

[0073] The processor is used to store one or more programs;

[0074] When the one or more programs are executed by the one or more processors, the direct - current converter station planning method for the UHV AC - DC hybrid power grid as described above is implemented.

[0075] In a fourth aspect, a computer - readable storage medium is provided, on which a computer program is stored. When the computer program is executed, the direct - current converter station planning method for the UHV AC - DC hybrid power grid as described above is implemented.

[0076] One or more of the above - mentioned technical solutions of the present invention have at least one or more of the following beneficial effects:

[0077] The present invention provides a method and device for planning a DC converter station in a UHV AC / DC hybrid power grid, including: performing system partitioning on the power grid to be planned based on the multi-infeed DC interaction impact factors between nodes in the power grid to be planned; generating multiple alternative landing point schemes for each system partition based on the node characteristics in each system partition and a pre-constructed alternative landing point area planning model; respectively determining the comprehensive evaluation values of the multiple alternative landing point schemes for the system partitions in the converter station planning evaluation index system; and selecting the alternative landing point scheme for the system partition with the highest comprehensive evaluation value as the landing point scheme for the system partition. The technical solution provided by the present invention is simple and easy to implement, which is beneficial to engineering practice. Specifically, by introducing the multi-infeed interaction impact factors, the technical solution provided by the present invention establishes an alternative landing point area planning model considering the safety constraints of system operation, and formulates a more objective candidate scheme for the location selection of the converter station. An evaluation system for the location selection of a HVDC converter station based on TOPSIS is constructed from three aspects of economy, safety and stability of the candidate scheme, so as to avoid the single evaluation index affecting the planning result. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 is a schematic flow chart of the main steps of the method for planning a DC converter station in a UHV AC / DC hybrid power grid according to an embodiment of the present invention;

[0079] Figure 2 is a system diagram of IEEE 39 nodes with a high proportion of new energy according to an embodiment of the present invention;

[0080] Figure 3 is a schematic diagram of sub-region division into two areas according to an embodiment of the present invention;

[0081] Figure 4 is a schematic diagram of sub-region division into three areas according to an embodiment of the present invention;

[0082] Figure 5 is a schematic diagram of the rationality of partitioning according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0083] The following further elaborates in detail on the specific embodiments of the present invention with reference to the accompanying drawings.

[0084] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0085] As disclosed in the background art, the advantages of high-voltage direct current technology in large-scale power supply have promoted its application in cross-regional power transmission, especially in the optimal allocation of renewable energy. In the receiving-end power grid with multiple DC feeders, the coupling between the AC-DC system and between different DC lines poses severe challenges to the security and stability of the power system.

[0086] The problem of the location selection of high-voltage DC converter stations is a complex decision-making problem in the power system, which requires comprehensive consideration of decision-making objectives, system security, operation economy, and project implementation difficulty. At present, the location selection optimization methods mainly draw on methods such as substation location selection, location selection of medium-voltage flexible DC ring network control devices, and DC landing point selection. Usually, according to the power transmission and reception relationship of the power system, planners directly formulate a series of DC landing point schemes. On this basis, indicators such as system security, stability, and economy are calculated, and then analyzed and evaluated. Through the comparison of the results, the final DC landing point scheme is determined. At present, there is little research on the planning method of high-voltage DC converter stations in power grids with a high proportion of new energy, and the evaluation index system is relatively single. Therefore, it is of great significance to study in detail the screening strategy of the preliminary location selection scheme of high-voltage DC converter stations under the new power grid and to propose a more perfect evaluation index system for converter station location selection.

[0087] In order to improve the above problems, the present invention provides a planning method and device for DC converter stations in a UHV AC-DC hybrid power grid, including: performing system partitioning on the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned; generating multiple system partition alternative landing point schemes based on the node characteristics in each system partition and a pre-constructed alternative landing point area planning model; respectively determining the comprehensive evaluation values of the multiple system partition alternative landing point schemes in the converter station planning evaluation index system; and selecting the system partition alternative landing point scheme with the highest comprehensive evaluation value as the system partition landing point scheme. The technical solution provided by the present invention is simple and easy to implement, which is beneficial to engineering practice. Specifically, the technical solution provided by the present invention introduces multi-infeed interaction influence factors, considers the system operation security constraints to establish an alternative landing point area planning model, and more objectively formulates the candidate schemes for converter station location selection. A TOPSIS-based location selection evaluation system for high-voltage DC converter stations is constructed from three aspects of economy, security, and stability of the candidate schemes, avoiding the influence of a single evaluation index on the planning results.

[0088] The above scheme will be elaborated in detail below.

[0089] Embodiment 1

[0090] Refer to the appendix Figure 1 , Figure 1 which is a schematic diagram of the main steps of the planning method for DC converter stations in a UHV AC-DC hybrid power grid according to an embodiment of the present invention. As Figure 1As shown in the figure, the method for planning a DC converter station in a UHV AC / DC hybrid power grid in an embodiment of the present invention mainly includes the following steps:

[0091] Step S101: Based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned, perform system partitioning on the power grid to be planned;

[0092] Step S102: Based on the node characteristics in each system partition and the pre-constructed alternative landing area planning model, generate multiple alternative landing plans for the system partitions;

[0093] Step S103: Respectively determine the comprehensive evaluation values of the multiple alternative landing plans for the system partitions in the converter station planning evaluation index system;

[0094] Step S104: Select the alternative landing plan for the system partition with the highest comprehensive evaluation value as the landing plan for the system partition.

[0095] In this embodiment, the performing system partitioning on the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned includes:

[0096] Based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned, determine the interaction influence index between nodes in the power grid to be planned;

[0097] Taking the interaction influence index between nodes in the power grid to be planned as a reference, use the k-means algorithm for clustering;

[0098] Divide the nodes in the same clustering cluster in the clustering result into one system partition.

[0099] In an implementation manner, the multi-infeed DC interaction influence factors between nodes in the power grid to be planned can directly reflect the mutual influence and coupling relationship between multiple DC systems, and on this basis, reflect the relative strength relationship between the AC / DC systems. Specifically, it can be explained as follows: When a small-capacity reactor is put into the i-th node, so that the voltage drop amplitude of this node is exactly 1%, the ratio of the voltage change amount of other j nodes to the 1% voltage change amount of the i-th node, the multi-infeed DC interaction influence factor between nodes in the power grid to be planned is as follows:

[0100]

[0101] In the above formula, MIIF ji is the multi-infeed DC interaction influence factor between node j and node i, △U j is the voltage change amount of node j, △U i is the voltage change amount of node i, Z eqji is the equivalent reactance between node j and node i, Z eqii is the equivalent self-impedance of node i.

[0102] In one embodiment, since MIIF ij and MIIF ji are not necessarily equal and cannot uniformly reflect the strength of the interaction between connection node i and node j, the MIIF index is unified, and thus the node interaction influence index is proposed. The interaction influence index between nodes in the power grid to be planned is as follows:

[0103]

[0104] In the above formula, B ij is the interaction influence index between node i and node j, B ji is the interaction influence index between node j and node i, and MIIF ij is the multi-infeed DC interaction influence factor between node i and node j.

[0105] In this embodiment, generating multiple system partition alternative landing point schemes based on the node characteristics in each system partition and the pre-constructed alternative landing point area planning model includes:

[0106] Step 1 Initialize the number of iterations;

[0107] Step 2 Substitute the node characteristics in each system partition into the pre-constructed alternative landing point area planning model and solve to obtain the optimization result, and use the optimization result as the system partition alternative landing point scheme;

[0108] Judge whether the preset number of iterations is reached. If so, output all system partition alternative landing point schemes. Otherwise, increment the number of iterations by 1 and return to Step 2;

[0109] Among them, the optimization result includes at least one of the following: the number of HVDC converter stations in the system, the number of HVDC converter stations planned for each system partition, and the HVDC converter station planning coefficients of each node in each system partition. The node characteristics include at least one of the following: voltage, power, active load, and reactive load.

[0110] In one embodiment, the pre-constructed alternative landing point area planning model includes: an objective function with the optimal economy as the goal and its corresponding constraints.

[0111] In one embodiment, the objective function is as follows:

[0112]

[0113] In the above formula, f is the objective value, N l is the number of branches in the system, G ij is the conductance of branch ij, U i is the voltage of node i, U jis the voltage of node j, θ ij is the phase angle of branch ij, N C is the number of HVDC converter stations in the system, η c is the conversion efficiency of HVDC converter station c, P c is the active power of HVDC converter station c, i, j ∈ [1, N], and N is the number of nodes in the system.

[0114] In one embodiment, the constraint conditions are as follows:

[0115]

[0116] P Gi,min ≤ P Gi ≤ P Gi,max

[0117] Q Gi,min ≤ Q Gi ≤ Q Gi,max

[0118] P Wi,min ≤ P Wi ≤ P Wi,max

[0119] U i,min ≤ U i ≤ U i,max

[0120] P ij,min ≤ P ij ≤ P ij,max

[0121] In the above formula, P Gi is the active power output of the generator at node i, P Wi is the active power output of the wind turbine at node i, σ i is the HVDC converter station planning coefficient at node i. If an HVDC converter station is established at node i, then σ i = 1, otherwise, σ i = 0, P Li is the active load at node i, b ij is the susceptance of branch ij, Q Gi is the reactive power output of the generator at node i, Q Li is the active load at node i, P Gi,min is the minimum value of the active power output of the generator at node i, P Gi,max is the maximum value of the active power output of the generator at node i, Q Gi,min is the minimum value of the reactive power output of the generator at node i, Q Gi,max is the maximum value of the reactive power output of the generator at node i, P Wi,minis the minimum value of the fan output at node i, P Wi,max is the maximum value of the fan output at node i, U i,min is the minimum value of the node voltage at node i, U i,max is the maximum value of the node voltage at node i, P ij,min is the minimum value of the active power that can be transmitted through branch ij, P ij is the active power that can be transmitted through branch ij, P ij,max is the maximum value of the active power that can be transmitted through branch ij.

[0122] In one embodiment, the constraint conditions are as follows:

[0123]

[0124] SCR i ≥σ i SCR min

[0125] In the above formula, N bn is the number of nodes in system partition n, a n is the number of HVDC converter stations planned in system partition n, SCR i is the short-circuit ratio of node i, SCR min is the minimum short-circuit ratio.

[0126] In this embodiment, determining the comprehensive evaluation values of the multiple system partition alternative landing point schemes in the converter station planning evaluation index system respectively includes:

[0127] Determining the index values of each final-level index of the system partition alternative landing point scheme s in the converter station planning evaluation index system;

[0128] Based on the index values of each final-level index of the system partition alternative landing point scheme s in the converter station planning evaluation index system and the weights corresponding to each final-level index, determining the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system.

[0129] In one embodiment, the converter station planning evaluation index system is a two-level index system, the first-level index is the comprehensive evaluation value, and the second-level indexes include: economic index, integrity index, balance index, minimum multi-infeed short-circuit ratio index, and stability index.

[0130] In one embodiment, the economic index I eco (s) of the system partition alternative landing point scheme s in the converter station planning evaluation index system is calculated as follows:

[0131] I eco (s) = f s

[0132] The integrity index I of the alternative landing point scheme s of the system partition in the converter station planning evaluation index system whole (s) is calculated as follows:

[0133]

[0134] The balance index I of the alternative landing point scheme s of the system partition in the converter station planning evaluation index system balance (s) is calculated as follows:

[0135]

[0136] The minimum multi-infeed short-circuit ratio index I of the alternative landing point scheme s of the system partition in the converter station planning evaluation index system scr (s) is calculated as follows:

[0137] I scr (s) = min{MISCR sc , s = 1, 2,..., m, c = 1, 2,..., N C}

[0138] The stability index I of the alternative landing point scheme s of the system partition in the converter station planning evaluation index system lfd (s) is calculated as follows:

[0139]

[0140] In the above formula, f s is the active power loss of the high-voltage DC converter station under the alternative landing point scheme s of the system partition, RK sc is the risk resistance coefficient of the node c of the high-voltage DC converter station under the alternative landing point scheme s of the system partition, m is the number of alternative landing point schemes of the system partition, MISCR sc is the multi-infeed DC short-circuit ratio of the node c of the high-voltage DC converter station under the alternative landing point scheme s of the system partition, N C is the number of high-voltage DC converter stations in the system, N l is the number of branches in the system, S ftmax is the maximum apparent power of the branch ft, S s,ft is the actual transmission power of the branch ft under the alternative landing point scheme s of the system partition.

[0141] Among them, the risk resistance coefficient of the node c of the high-voltage DC converter station under the alternative landing point scheme s of the system partition is as follows:

[0142]

[0143] In the above formula, MIIF icIt is the multi-infeed DC interaction influence factor between node i and node c, and N is the number of nodes in the system.

[0144] Among them, the multi-infeed DC short-circuit ratio at the node of the high-voltage DC converter station c under the system partition alternative landing point scheme s is as follows:

[0145]

[0146] In the above formula, P dci is the DC power fed into at node i, S aci is the short-circuit capacity at node i, MIIF ci is the multi-infeed DC interaction influence factor between node c and node i, P dc is the DC power fed into at node c.

[0147] In one embodiment, the weights corresponding to the respective final-level indicators are as follows:

[0148]

[0149] In the above formula, ω k is the weight corresponding to the final-level indicator k, λ k is the weight corresponding to the final-level indicator k obtained by using the analytic hierarchy process, a k is the weight corresponding to the final-level indicator k obtained by using the entropy weight method, and q is the number of final-level indicators.

[0150] In one embodiment, determining the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system based on the index values of the respective final-level indicators and the weights corresponding to the respective final-level indicators in the converter station planning evaluation index system based on the system partition alternative landing point scheme s includes:

[0151] Based on the index values of the respective final-level indicators and the weights corresponding to the respective final-level indicators in the converter station planning evaluation index system based on the system partition alternative landing point scheme s, use the TOPSIS algorithm to determine the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system.

[0152] In a specific embodiment, as Figure 2 shown, taking the improved IEEE 39-node system with a high proportion of new energy as an example for analysis and verification, where the number of planned high-voltage DC converter stations is 3, and the active power fed into the system through the converter stations is set to 800 MW. To prevent the interaction between the converter stations and the power generation stations, the PV nodes in the system are excluded from the alternative nodes of the converter stations.

[0153] The IEEE 39 - node system is partitioned according to the partitioning method. The partitioning objectives are set to no sub - region division, division into two sub - regions, and division into three sub - regions. The optimization results of the initial scheme of the high - voltage converter station under different partitioning objectives are as follows:

[0154] As Figure 3 shown, without sub - region division: that is, without PV nodes, and the nodes in this region are nodes 1 to 29. The converter station site - selection schemes are nodes 4, 8, and 20.

[0155] Dividing into two sub - regions: The first sub - region includes nodes 1, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and the second sub - region includes 2, 3, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29. The converter station site - selection schemes are nodes 3, 8, and 20.

[0156] As Figure 4 shown, dividing into three sub - regions (as Figure 3 ): The first sub - region includes nodes 1, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, the second sub - region includes nodes 2, 3, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and the third sub - region includes 25, 26, 27, 28, 29. The converter station site - selection schemes are nodes 8, 20, and 29.

[0157] On the premise of dividing into three sub - regions, taking all the nodes included in Region 1 as an example, the reliability of introducing MIIF partitioning is verified, as Figure 5 shown. The higher the node interaction influence index B, the greater the interaction between the two nodes connected to the DC. The average value of the B values of all nodes in Sub - region 1 is significantly higher than the average value of the B values of the nodes in Sub - region 1 and the nodes in other regions, indicating that the influence degree between nodes in the same region is relatively large, and the method of building a high - voltage DC converter station through partitioning is correct.

[0158] The economic index, safety index, and stability index values of the three schemes are calculated respectively, and the obtained data are shown in Table 1.

[0159] Table 1

[0160]

[0161] According to the combined weighting method, after calculating the AHP weights and EMM weights of each index, the comprehensive weights are obtained, as shown in Table 2.

[0162] Table 2

[0163]

[0164]

[0165] The TOPSIS evaluation method is used to calculate the scores of each plan. The scores of the three plans are 0.4843, 0.5462, and 0.4717 respectively. The greater the relative closeness of the plan, the better the plan. Therefore, the final plan to be adopted by the system is Plan 2, that is, to select Node 3, Node 8, and Node 20 as the site addresses for the converter stations.

[0166] Embodiment 2

[0167] Based on the same inventive concept, the present invention also provides a DC converter station planning device for a UHV AC / DC hybrid power grid. The DC converter station planning device for the UHV AC / DC hybrid power grid includes:

[0168] A partitioning module for partitioning the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned;

[0169] An analysis module for generating multiple alternative landing point plans for system partitioning based on the node characteristics in each system partition and a pre-constructed alternative landing area planning model;

[0170] An evaluation module for respectively determining the comprehensive evaluation values of the multiple alternative landing point plans for system partitioning in the converter station planning evaluation index system;

[0171] A screening module for selecting the alternative landing point plan for system partitioning with the highest comprehensive evaluation value as the landing point plan for system partitioning.

[0172] Preferably, the partitioning of the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned includes:

[0173] Determining the interaction influence index between nodes in the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned;

[0174] Using the k-means algorithm for clustering with reference to the interaction influence index between nodes in the power grid to be planned;

[0175] Dividing the nodes in the same clustering cluster in the clustering result into one system partition.

[0176] Furthermore, the multi-infeed DC interaction influence factors between nodes in the power grid to be planned are as follows:

[0177]

[0178] In the above formula, MIIF ji is the multi-infeed DC interaction influence factor between node j and node i, and △U j is the voltage change of node j, and △Ui is the voltage change of node i, and Z eqji is the equivalent reactance between node j and node i, and Z eqii is the equivalent self-impedance of node i.

[0179] Furthermore, the interaction influence index between nodes in the power grid to be planned is as follows:

[0180]

[0181] In the above formula, B ij is the interaction influence index between node i and node j, and B ji is the interaction influence index between node j and node i, and MIIF ij is the multi-infeed DC interaction influence factor between node i and node j.

[0182] Preferably, generating multiple system partition alternative landing point schemes based on the node characteristics in each system partition and the pre-constructed alternative landing point area planning model includes:

[0183] Step 1 Initialize the iteration times;

[0184] Step 2 Substitute the node characteristics in each system partition into the pre-constructed alternative landing point area planning model and solve it to obtain the optimization result, and use the optimization result as the system partition alternative landing point scheme;

[0185] Judge whether the preset iteration times are reached. If so, output all the system partition alternative landing point schemes. Otherwise, increment the iteration times by 1 and return to Step 2;

[0186] Among them, the optimization result includes at least one of the following: the number of HVDC converter stations in the system, the number of HVDC converter stations planned for each system partition, and the HVDC converter station planning coefficient of each node in each system partition. The node characteristics include at least one of the following: voltage, power, active load, and reactive load.

[0187] Furthermore, the pre-constructed alternative landing point area planning model includes: an objective function with the optimal economy as the goal and its corresponding constraints.

[0188] Furthermore, the objective function is as follows:

[0189]

[0190] In the above formula, f is the objective value, and N l is the number of branches in the system, and G ij is the conductance of branch ij, and U i is the voltage of node i, and U j is the voltage of node j, and θ ijis the phase angle of branch ij, N C is the number of HVDC converter stations in the system, η c is the conversion efficiency of HVDC converter station c, P c is the active power of HVDC converter station c, i, j ∈ [1, N], and N is the number of nodes in the system.

[0191] Furthermore, the constraint conditions are as follows:

[0192]

[0193] P Gi,min ≤P Gi ≤P Gi,max

[0194] Q Gi,min ≤Q Gi ≤Q Gi,max

[0195] P Wi,min ≤P Wi ≤P Wi,max

[0196] U i,min ≤U i ≤U i,max

[0197] P ij,min ≤P ij ≤P ij,max

[0198] In the above formula, P Gi is the active power output of the generator at node i, P Wi is the active power output of the wind turbine at node i, σ i is the HVDC converter station planning coefficient at node i. If an HVDC converter station is established at node i, then σ i = 1, otherwise, σ i = 0, P Li is the active load at node i, b ij is the susceptance of branch ij, Q Gi is the reactive power output of the generator at node i, Q Li is the active load at node i, P Gi,min is the minimum value of the active power output of the generator at node i, P Gi,max is the maximum value of the active power output of the generator at node i, Q Gi,min is the minimum value of the reactive power output of the generator at node i, Q Gi,max is the maximum value of the reactive power output of the generator at node i, P Wi,min is the minimum value of the wind turbine output at node i, P Wi,maxis the maximum value of the fan output of node i, U i,min is the minimum value of the node voltage of node i, U i,max is the maximum value of the node voltage of node i, P ij,min is the minimum value of the active power that can be transmitted by branch ij, P ij is the active power that can be transmitted by branch ij, P ij,max is the maximum value of the active power that can be transmitted by branch ij.

[0199] Furthermore, the constraint conditions are as follows:

[0200]

[0201] SCR i ≥σ i SCR min

[0202] In the above formula, N bn is the number of nodes in system partition n, a n is the number of HVDC converter stations planned in system partition n, SCR i is the short-circuit ratio of node i, SCR min is the minimum short-circuit ratio.

[0203] Preferably, the comprehensive evaluation values of the multiple system partition alternative landing point schemes in the converter station planning evaluation index system are determined respectively, including:

[0204] Determine the index values of each final-level index of the system partition alternative landing point scheme s in the converter station planning evaluation index system;

[0205] Based on the index values of each final-level index of the system partition alternative landing point scheme s in the converter station planning evaluation index system and the weights corresponding to each final-level index, determine the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system.

[0206] Furthermore, the converter station planning evaluation index system is a two-level index system, the first-level index is the comprehensive evaluation value, and the second-level indexes include: economic index, integrity index, balance index, minimum multi-infeed short-circuit ratio index, and stability index.

[0207] Furthermore, the economic index I eco (s) of the system partition alternative landing point scheme s in the converter station planning evaluation index system is calculated as follows:

[0208] I eco (s) = f s

[0209] The integrity index I of the system partition alternative landing point scheme s in the converter station planning evaluation index systemwhole The calculation formula of (s) is as follows:

[0210]

[0211] The balance index I of the alternative landing point scheme s of the system partition in the converter station planning evaluation index system balance The calculation formula of (s) is as follows:

[0212]

[0213] The minimum multi - infeed short - circuit ratio index I of the alternative landing point scheme s of the system partition in the converter station planning evaluation index system scr The calculation formula of (s) is as follows:

[0214] I scr (s)=min{MISCR sc , s = 1, 2,..., m, c = 1, 2,..., N C}

[0215] The stability index I of the alternative landing point scheme s of the system partition in the converter station planning evaluation index system lfd The calculation formula of (s) is as follows:

[0216]

[0217] In the above formula, f s is the active power loss of the HVDC converter station under the alternative landing point scheme s of the system partition, RK sc is the risk resistance coefficient of the node c of the HVDC converter station under the alternative landing point scheme s of the system partition, m is the number of alternative landing point schemes of the system partition, MISCR sc is the multi - infeed DC short - circuit ratio of the node c of the HVDC converter station under the alternative landing point scheme s of the system partition, N C is the number of HVDC converter stations in the system, N l is the number of branches in the system, S ftmax is the maximum apparent power of the branch ft, S s,ft is the actual transmission power of the branch ft under the alternative landing point scheme s of the system partition.

[0218] Furthermore, the risk resistance coefficient of the node c of the HVDC converter station under the alternative landing point scheme s of the system partition is as follows:

[0219]

[0220] In the above formula, MIIF ic is the multi - infeed DC interaction influence factor between node i and node c, and N is the number of nodes in the system.

[0221] Furthermore, the multi-infeed DC short-circuit ratio at the node of the high-voltage DC converter station c under the system partition alternative landing point scheme s is as follows:

[0222]

[0223] In the above formula, P dci is the DC power fed into node i, S aci is the short-circuit capacity at node i, MIIF ci is the multi-infeed DC interaction factor between node c and node i, and P dc is the DC power fed into node c.

[0224] Furthermore, the weights corresponding to the respective final-level indicators are as follows:

[0225]

[0226] In the above formula, ω k is the weight corresponding to the final-level indicator k, λ k is the weight corresponding to the final-level indicator k obtained by using the analytic hierarchy process, a k is the weight corresponding to the final-level indicator k obtained by using the entropy weight method, and q is the number of final-level indicators.

[0227] Furthermore, determining the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system based on the index values of the respective final-level indicators and the weights corresponding to the respective final-level indicators in the system partition alternative landing point scheme s in the converter station planning evaluation index system includes:

[0228] Based on the index values of the respective final-level indicators and the weights corresponding to the respective final-level indicators in the system partition alternative landing point scheme s in the converter station planning evaluation index system, the TOPSIS algorithm is used to determine the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system.

[0229] Example 3

[0230] Based on the same inventive concept, the present invention further provides a computer device, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of a method for planning a DC converter station in a UHV AC / DC hybrid power grid in the above embodiments.

[0231] Embodiment 4

[0232] Based on the same inventive concept, the present invention further provides a storage medium, specifically a computer-readable storage medium (Memory). The computer-readable storage medium is a memory device in a computer device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and, of course, the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, and this storage space stores the operating system of the terminal. And, one or more instructions suitable for being loaded and executed by the processor are also stored in this storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The one or more instructions stored in the computer-readable storage medium can be loaded and executed by the processor to implement the steps of a method for planning a DC converter station in a UHV AC / DC hybrid power grid in the above embodiments.

[0233] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0234] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0235] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0236] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0237] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: still, modifications or equivalent replacements can be made to the specific implementation manners of the present invention, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A method for planning a DC converter station in a UHV AC / DC hybrid power grid, characterized in that, The method includes: Performing system partitioning on the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned; Generating multiple alternative landing point plans for each system partition based on the node characteristics in each system partition and the pre-constructed alternative landing point area planning model; Respectively determining the comprehensive evaluation values of the multiple alternative landing point plans for each system partition in the converter station planning evaluation index system; Selecting the alternative landing point plan for the system partition with the highest comprehensive evaluation value as the landing point plan for the system partition.

2. The method according to claim 1, characterized in that, The performing system partitioning on the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned includes: Determining the interaction influence indexes between nodes in the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned; Taking the interaction influence indexes between nodes in the power grid to be planned as a reference and using the k-means algorithm for clustering; Dividing the nodes in the same clustering cluster in the clustering result into one system partition.

3. The method according to claim 2, characterized in that, The multi-infeed DC interaction influence factors between nodes in the power grid to be planned are as follows: In the above formula, MIIF ji is the multi-infeed DC interaction influence factor between node j and node i, △U j is the voltage change of node j, △U i is the voltage change of node i, Z eqji is the equivalent reactance between node j and node i, Z eqii is the equivalent self-impedance of node i.

4. The method according to claim 3, wherein The interaction influence indexes between nodes in the power grid to be planned are as follows: In the above formula, B ij is the interaction influence index between node i and node j, and B ji is the interaction influence index between node j and node i. MIIF ij is the multi-infeed DC interaction influence factor between node i and node j.

5. The method according to claim 1, characterized in that, The generating multiple alternative landing point plans for each system partition based on the node characteristics in each system partition and the pre-constructed alternative landing point area planning model includes: Step 1: Initializing the number of iteration times; Step 2: Substituting the node characteristics in each system partition into the pre-constructed alternative landing point area planning model and solving to obtain the optimization result, and using the optimization result as the alternative landing point plan for the system partition; Judging whether the preset number of iteration times is reached. If so, outputting all the alternative landing point plans for each system partition; otherwise, increasing the number of iteration times by 1 and then returning to Step 2; Wherein, the optimization result includes at least one of the following: the number of HVDC converter stations in the system, the number of HVDC converter stations planned for each system partition, and the HVDC converter station planning coefficients of each node in each system partition, and the node characteristics include at least one of the following: voltage, power, active load, and reactive load.

6. The method according to claim 5, wherein The pre-constructed alternative landing point area planning model includes: an objective function with the optimal economy as the goal and its corresponding constraint conditions.

7. The method according to claim 6, wherein The objective function is as follows: In the above formula, f is the target value, N l is the number of branches of the system, G ij is the conductance of branch ij, U i is the voltage of node i, U j is the voltage of node j, θ ij is the phase angle of branch ij, N C is the number of HVDC converter stations in the system, η c is the conversion efficiency of HVDC converter station c, P c is the active power of HVDC converter station c, i, j ∈ [1, N], and N is the number of nodes in the system.

8. The method according to claim 7, wherein The constraint conditions are as follows: P Gi,min ≤P Gi ≤P Gi,max Q Gi,min ≤Q Gi ≤Q Gi,max P Wi,min ≤P Wi ≤P Wi,max U i,min ≤U i ≤U i,max P ij,min ≤P ij ≤P ij,max In the above formula, P Gi is the active power output of the generator at node i, P Wi is the active power output of the wind turbine at node i, σ i is the HVDC converter station planning coefficient at node i. If an HVDC converter station is established at node i, then σ i = 1; otherwise, σ i = 0. P Li is the active power load at node i, b ij is the susceptance of branch ij, Q Gi is the reactive power output of the generator at node i, Q Li is the active power load at node i, P Gi,min is the minimum value of the active power output of the generator at node i, P Gi,max is the maximum value of the active power output of the generator at node i, Q Gi,min is the minimum value of the reactive power output of the generator at node i, Q Gi,max is the maximum value of the reactive power output of the generator at node i, P Wi,min is the minimum value of the wind turbine output at node i, P Wi,max is the maximum value of the wind turbine output at node i, U i,min is the minimum value of the node voltage at node i, U i,max is the maximum value of the node voltage at node i, P ij,min is the minimum value of the active power that can be transmitted by branch ij, P ij is the active power that can be transmitted by branch ij, P ij,max is the maximum value of the active power that can be transmitted by branch ij.

9. The method according to claim 7, characterized in that The constraint conditions are as follows: SCR i ≥σ i SCR min In the above formula, N bn is the number of nodes in system partition n, a n is the number of HVDC converter stations planned for system partition n, SCR i is the short-circuit ratio of node i, and SCR min is the minimum short-circuit ratio.

10. The method according to claim 1, characterized in that, The respectively determining the comprehensive evaluation values of the multiple alternative landing point plans for each system partition in the converter station planning evaluation index system includes: Determining the index values of each final-level index of the alternative landing point plan s for the system partition in the converter station planning evaluation index system; Based on the index values of each final-level index of the alternative landing point plan s for the system partition in the converter station planning evaluation index system and the weights corresponding to each final-level index, determining the comprehensive evaluation value of the alternative landing point plan s for the system partition in the converter station planning evaluation index system.

11. The method according to claim 10, wherein The converter station planning evaluation index system is a two-level index system, the first-level index is the comprehensive evaluation value, and the second-level indexes include: economic index, integrity index, balance index, minimum multi-infeed short-circuit ratio index, and stability index.

12. The method according to claim 11, wherein The economic index I of the alternative landing point scheme s of the system partition in the planning evaluation index system of the converter station eco (s) is calculated as follows: I eco (s) = f s The integrity index I of the alternative landing point scheme s of the system partition in the evaluation index system of converter station planning whole (s) is calculated as follows: The balance index I of the alternative landing point scheme s of the system partition in the planning evaluation index system of the converter station balance (s) is calculated as follows: The minimum multi-infeed short-circuit ratio index I of the system partition alternative landing point scheme s in the converter station planning evaluation index system scr (s) is calculated as follows: I scr (s) = min{MISCR sc , s = 1, 2, ..., m, c = 1, 2, ..., N C} The stability index I of the alternative landing point scheme s of the system partition in the planning evaluation index system of the converter station lfd (s) is calculated as follows: In the above formula, f s is the active power loss of the HVDC converter station under the alternative landing point scheme s of the system partition, RK sc is the risk resistance coefficient of the node at the HVDC converter station c under the alternative landing point scheme s of the system partition, m is the number of alternative landing point schemes of the system partition, MISCR sc is the multi-infeed DC short-circuit ratio of the node at the HVDC converter station c under the alternative landing point scheme s of the system partition, N C is the number of HVDC converter stations in the system, N l is the number of branches in the system, S ftmax is the maximum apparent power of the branch ft, S s,ft is the actual transmission power of the branch ft under the alternative landing point scheme s of the system partition.

13. The method according to claim 12, characterized in that, The risk resistance coefficient of the node at the HVDC converter station c under the alternative landing point plan s for the system partition is as follows: In the above formula, MIIF ic is the multi-infeed DC interaction influence factor between node i and node c, and N is the number of nodes in the system.

14. The method according to claim 12, wherein The multi-infeed DC short-circuit ratio of the node at the HVDC converter station c under the alternative landing point plan s for the system partition is as follows: In the above formula, P dci is the DC power fed into node i, S aci is the short-circuit capacity at node i, MIIF ci is the multi-infeed DC interaction impact factor between node c and node i, and P dc is the DC power fed into node c.

15. The method according to claim 10, wherein The weights corresponding to each of the final-level indicators are as follows: In the above formula, ω k is the weight corresponding to the final-level index k, λ k is the weight corresponding to the final-level index k obtained by the analytic hierarchy process, a k is the weight corresponding to the final-level index k obtained by the entropy weight method, and q is the number of final-level indices.

16. The method according to claim 15, wherein, Determining the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system based on the index values of each final-level indicator in the converter station planning evaluation index system corresponding to the system partition alternative landing point scheme s and the weights corresponding to each final-level indicator, including: Based on the index values of each final-level indicator in the converter station planning evaluation index system corresponding to the system partition alternative landing point scheme s and the weights corresponding to each final-level indicator, using the TOPSIS algorithm to determine the comprehensive evaluation value of the system partition alternative landing point scheme s in the converter station planning evaluation index system.

17. An apparatus for a method of planning a DC converter station of a UHV AC / DC hybrid power grid according to any one of claims 1-16, characterized in that, The device includes: A partitioning module, configured to partition the power grid to be planned based on the multi-infeed DC interaction influence factors between nodes in the power grid to be planned; An analysis module, configured to generate multiple system partition alternative landing point schemes based on the node characteristics in each system partition and a pre-constructed alternative landing area planning model; An evaluation module, configured to respectively determine the comprehensive evaluation values of the multiple system partition alternative landing point schemes in the converter station planning evaluation index system; A screening module, configured to select the system partition alternative landing point scheme with the highest comprehensive evaluation value as the system partition landing point scheme.

18. A computer device, characterized in that, Including: One or more processors; The processor is configured to store one or more programs; When the one or more programs are executed by the one or more processors, implementing the DC converter station planning method for the UHV AC / DC hybrid power grid according to any one of claims 1 to 16.

19. A computer-readable storage medium, characterized in that, There is a computer program stored thereon, and when the computer program is executed, implementing the DC converter station planning method for the UHV AC / DC hybrid power grid according to any one of claims 1 to 16.

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