A master-slave coordination ring switching strategy optimization method and system

Abstract

The application relates to the technical field of electric power, and provides a main distribution coordination combined loop power supply strategy optimization method and system, which comprises the following steps: dividing a target distribution network into a plurality of topological regions, and obtaining a main distribution topological coupling relationship according to the connection relationship between each topological region and a main network power supply node; obtaining a loop current dominant component type of each loop path to be combined between regions according to obtained first and second voltage phasors of a first topological region and a second topological region to be combined; generating a candidate paired path set based on the criterion that different loop current dominant component types are allowed to be paired; and performing paired path loop current vector offset effect analysis on the candidate paired path set according to a to-be-combined path constraint transfer relationship matrix determined based on the main distribution topological coupling relationship, so as to obtain a target combined loop power supply strategy. The application can improve the effectiveness of combined loop power supply strategy generation and guarantee the safety and reliability of combined loop power supply operation.

Description

Technical Field

[0001] This invention relates to the field of power technology, and in particular to a method and system for optimizing a main distribution coordinated loop power transfer strategy. Background Technology

[0002] Distribution network loop transfer refers to the operation of transferring load from one power supply path to another by closing a tie switch, so as to achieve uninterrupted power supply to the load and improve the reliability of load power supply. The core of the loop transfer operation is to control the loop transfer current to not exceed the protection limit of the switch, so as to avoid the failure of the operation due to the operation of the protection device. Therefore, the accurate calculation of the loop transfer current is a key technology affecting the execution of the loop transfer operation.

[0003] Current methods for calculating the loop current in distribution networks primarily rely on voltage differences and load distribution on the distribution network side. The expected value of the loop current is calculated based on the voltage phasor difference and equivalent impedance on both sides of the loop point, and this is used to determine whether the loop closure conditions are met. However, this calculation method uses the main grid's operating state as a fixed boundary condition, neglecting the dynamic changes in voltage amplitude and phase at main grid power nodes. It directly ignores the fact that in practical applications, when multiple paths to be looped are powered by different main grid power nodes, the differences in current composition and dominant type generated by loop closure operations of different paths can lead to phase differences in the current generated by paired loop closures. Furthermore, the coupling relationship between the distribution network and the main grid is only represented by a simplified treatment of the equivalent impedance of the main transformer. In actual analysis, the impact of the topological relationship between power nodes within the main grid on the distribution network's loop closure operation is not considered, nor is the effect of the main grid's power flow distribution on the loop current. This results in the failure to discover and utilize the constraint and coordination relationships between paths, and the insufficient exploration of the optimization space for the loop current. Consequently, it is difficult to provide an effective loop closure and power transfer strategy, and the safety and reliability of the loop closure and power transfer operation cannot be truly guaranteed. Summary of the Invention

[0004] The purpose of this invention is to provide an optimization method for a main-distribution coordinated loop-connection power transfer strategy. By combining a loop-connection path pairing and combination mechanism based on the dominant component type analysis of loop-connection path current with a loop-connection path collaborative constraint relationship generation mechanism based on the topological coupling relationship between the distribution network and the main network, the method analyzes the loop-connection current vector cancellation effect that exists during the loop-connection operation, fully explores the optimization space of the loop-connection current, and optimizes the loop-connection power transfer strategy. This improves the effectiveness of the loop-connection power transfer strategy generation, effectively reduces the loop-connection current during the loop-connection operation, and thus ensures the safety and reliability of the loop-connection power transfer operation.

[0005] To achieve the above objectives, it is necessary to provide a method and system for optimizing the main-distribution coordinated loop transfer strategy.

[0006] In a first aspect, embodiments of the present invention provide a method for optimizing a master-distributor coordinated loop transfer supply strategy, the method comprising: The target distribution network is divided into several topological regions, and the main distribution topology coupling relationship is obtained based on the connection relationship between each topological region and the main grid power supply node. Obtain the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region to be closed, respectively, and obtain the dominant component type of the closing current for each path to be closed between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor; Based on the criteria that allow pairing of different dominant components of the loop current, all the proposed loop-closing paths are paired and combined to generate a candidate pairing path set; Based on the main-pair topology coupling relationship, the constraint transfer relationship matrix of the path to be closed is determined, and based on the constraint transfer relationship matrix of the path to be closed, the current vector cancellation effect analysis of the paired path closing is performed on the candidate paired path set to obtain the target closing and transfer strategy.

[0007] Furthermore, the step of dividing the target distribution network into several topological regions and obtaining the main-distribution topology coupling relationship based on the connection relationship between each topological region and the main grid power supply node includes: Based on the line connection relationship and switch status information of the target distribution network, each main power node is used as the root node, and the electrical connection nodes of the target distribution network are searched and grouped according to the breadth-first search algorithm to obtain multiple distribution networks, and each distribution network is used as a topology region. Obtain the main network connection topology and main network short-circuit capacity of each main network power node, and determine the main network electrical coupling path of each topology region pair based on the main network connection topology and the corresponding topology region connection relationship; Based on the main network electrical coupling path and the corresponding main network short-circuit capacity of each of the aforementioned topology regions, the corresponding coupling path parameters are determined; the coupling path parameters include the total equivalent impedance of the path and the equivalent power supply impedance of the path. The main-distribution topology coupling relationship is generated based on the power support capability parameters, each main grid electrical coupling path and the corresponding electrical coupling path parameters.

[0008] Further, the step of obtaining the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region to be merged includes: A first voltage phasor dataset and a second voltage phasor dataset corresponding to the first topological region and the second topological region are obtained respectively; both the first voltage phasor dataset and the second voltage phasor dataset include wide-area temporal phase data pairs of several measurement points. Wide-area temporal data with the same sampling time in the first voltage phasor dataset and the second voltage phasor dataset are grouped into a synchronous phasor data group, and the sampling time of the synchronous phasor data group is taken as the target sampling time. Calculate the deviation between the sampling time and the target sampling time for each of the wide-area temporal data pairs that are not included in the synchronization phasor data group. If the deviation is less than a preset synchronization threshold, add the corresponding wide-area temporal data pair to the synchronization phasor data group. The synchronization phasor data group is divided into a first synchronization data group and a second synchronization data group according to its topology region. The voltage phasors of all corresponding measurement points in the first synchronization data group and the second synchronization data group are weighted and averaged to obtain the corresponding first voltage phasor and second voltage phasor.

[0009] Further, the step of obtaining the dominant component type of the loop current for each loop-to-be-closed path between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor includes: Based on the first voltage phasor and the second voltage phasor, the phase angle difference of the terminal nodes of each of the paths to be closed is calculated, and the corresponding phase angle difference driving current component is calculated based on each of the terminal node phase angle differences. Obtain the load power difference of each of the end nodes of the path to be closed, and calculate the corresponding load difference drive current component based on the load power difference of each end node. Each of the aforementioned loop paths to be closed is constructed with its equivalent impedance as a reference, and the corresponding phase difference driving current component and load difference driving current component are mapped to the complex plane rectangular coordinate system to obtain the corresponding complex plane information; the complex plane information includes a first complex module, a first complex argument, a second complex module, and a second complex argument; Based on the complex plane information of each of the proposed loop-closing paths, the modulus-length relationship and phase relationship are analyzed to determine the type of dominant component of the corresponding loop-closing current.

[0010] Furthermore, the step of analyzing the modulus and phase relationships based on the complex plane information of each of the paths to be closed to determine the dominant component type of the closed-loop current includes: When the ratio of the first complex modulus to the second complex modulus of the loop to be closed is greater than a preset discrimination threshold, the corresponding loop current dominant component type is marked as phase angle difference dominant type. When the ratio of the first complex modulus to the second complex modulus of the loop to be closed is less than the reciprocal of the preset discrimination threshold, the corresponding loop current dominant component type is marked as load difference dominant type. When the ratio of the first complex modulus to the second complex modulus of the loop to be closed is within a preset ratio range, the difference between the first complex argument and the second complex argument is obtained as the corresponding phase angle, and the type of the dominant component of the loop current is determined according to the relationship between the phase angle and the preset phase coordination threshold.

[0011] Further, the step of determining the corresponding dominant component type of the closed-loop current based on the relationship between the phase angle and the preset phase coordination threshold includes: Determine whether the phase angle is less than the preset phase coordination threshold. If not, mark the type of the loop current dominant component as mixed dominant type. Otherwise, obtain the vector and argument of the phase angle difference driving current component and the load difference driving current component. Calculate the first and second argument deviations of the vector and argument relative to the first and second complex arguments, respectively; When the first phase angle deviation is less than the second phase angle deviation, the type of dominant component of the closed loop current is marked as the phase angle difference dominant type; When the first phase deviation is greater than the second phase deviation, the type of the dominant component of the closed loop current is marked as the load difference dominant type.

[0012] Further, the step of determining the path constraint transfer relationship matrix of the loop to be merged based on the primary-secondary topological coupling relationship includes: Based on the main-partition topology coupling relationship, the common influence nodes of each path pair to be merged are obtained, and the corresponding equivalent circuit model is constructed with the common influence nodes as observation points; the equivalent circuit model includes equivalent voltage sources and equivalent impedance networks; Based on the equivalent circuit model, the influence of one path performing a loop-closing operation on the loop-closing current vector of the other path in each of the paths to be closed is determined, the corresponding path constraint transfer vector is obtained, and the constraint transfer relationship of the paths to be closed is constructed based on the path constraint transfer vector. Generate the constraint transitivity matrix of the paths to be merged based on the constraint transitivity of all the paths to be merged.

[0013] Further, the step of performing pairing path loop current vector cancellation effect analysis on the candidate pairing path set based on the constraint transfer relationship matrix of the path to be closed, and obtaining the target cross-domain pairing path includes: Based on the constraint transfer relationship matrix of the path to be merged, obtain the constraint transfer vector to be analyzed for each group of candidate paired paths; Based on the first loop current vector, the second loop current vector, and the constraint transfer vector to be analyzed for each group of candidate pairing paths, a corresponding loop current vector triangle is constructed in the complex plane. Each of the closed-loop current vector triangles is subjected to morphological analysis to obtain the corresponding geometric morphological features; the geometric morphological features include the first and second cosine values ​​of the included angle between the constraint transfer vector to be analyzed and the first and second closed-loop current vectors, respectively. When the first and second cosine values ​​of the candidate pairing paths in each group are both negative, it is determined that the corresponding candidate pairing path has a loop current vector cancellation effect, and the candidate pairing path is added to the cross-domain pairing path set. According to the preset pairing path screening strategy, the cross-domain pairing path set is subjected to path screening analysis, and the target loop-closing transfer strategy is generated based on the obtained optimal pairing path; the preset pairing path screening strategy includes at least one of the minimum loop-closing current strategy and the maximum offsetting effect strategy.

[0014] Further, when the preset pairing path screening strategy is the minimum loop-closing current strategy, the target loop-closing transfer strategy is generated based on the cross-domain pairing path corresponding to the minimum module length total loop-closing current vector in the cross-domain pairing path set; wherein, the calculation steps for the total loop-closing current vector of each group of cross-domain pairing paths in the cross-domain pairing path set include: Obtain the first loop current vector corresponding to the first loop-closing path and the second loop current vector corresponding to the second loop-closing path in each group of cross-domain pairing paths; Based on the constraint transfer relationship matrix of the path to be merged, obtain the first constraint transfer vector generated by the first merging path on the second merging path when the first merging path performs the merging operation in each group of cross-domain pairing paths, and the second constraint transfer vector generated by the second merging path on the first merging path when the second merging path performs the merging operation. The first loop current vector, the second loop current vector, the first constraint transfer vector, and the second constraint transfer vector corresponding to the cross-domain pairing paths of each group are superimposed in the complex plane to obtain the corresponding total loop current vector.

[0015] Secondly, embodiments of the present invention provide a master-distributor coordinated loop-based supply strategy optimization system, the system comprising: The main-distribution coupling relationship analysis module is used to divide the target distribution network into several topological regions and obtain the main-distribution topological coupling relationship based on the connection relationship between each topological region and the main power supply node. The loop current type analysis module is used to obtain the dominant component type of the loop current for each loop-to-be-closed path between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region, respectively. The candidate pairing path acquisition module is used to pair and combine all the paths to be closed based on the criteria that allow pairing of different dominant components of the closing current, and generate a candidate pairing path set. The target loop-closing path acquisition module is used to determine the constraint transfer relationship matrix of the loop-closing path to be closed based on the main-pair topology coupling relationship, and to perform a pairing path loop-closing current vector cancellation effect analysis on the candidate pairing path set based on the constraint transfer relationship matrix of the loop-closing path to be closed, so as to obtain the target loop-closing transfer strategy.

[0016] This invention provides a method and system for optimizing a main-distribution coordinated loop-connection power transfer strategy. The method divides the target distribution network into several topological regions, obtains the main-distribution topological coupling relationship based on the connection relationship between each topological region and the main grid power supply nodes, acquires the first and second voltage phasors corresponding to the first and second topological regions to be connected, respectively, and obtains the dominant component type of the loop current for each path to be connected between the first and second topological regions based on the first and second voltage phasors. Then, based on the criteria for allowing pairing of different dominant component types of loop current, all paths to be connected are paired to generate a candidate pairing path set. The constraint transfer relationship matrix of the paths to be connected is determined based on the main-distribution topological coupling relationship. Finally, based on the constraint transfer relationship matrix, the loop current vector cancellation effect analysis of the candidate pairing path set is performed to obtain the technical solution of the target loop-connection power transfer strategy. Compared with existing technologies, this main-distribution coordinated loop-connection power transfer strategy optimization method combines a loop-connection path pairing and combination mechanism based on the analysis of the dominant component type of the loop-connection path current with a loop-connection path coordinated constraint relationship generation mechanism based on the topological coupling relationship between the distribution network and the main network. This method can effectively analyze the loop-connection current vector cancellation effect during the loop-connection operation, fully explore the optimization space of the loop-connection current, and optimize the loop-connection power transfer strategy. It can improve the effectiveness of the loop-connection power transfer strategy generation, effectively reduce the loop-connection current during the loop-connection operation, and thus ensure the safety and reliability of the loop-connection power transfer operation. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the optimization method of the main-distributor coordinated loop transfer supply strategy in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the application scenario of the main-distributor coordinated loop transfer supply strategy optimization method in this embodiment of the invention; Figure 3This is a schematic diagram of the main-distributor coordinated loop transfer supply strategy optimization system in an embodiment of the present invention; The attached figures are labeled as follows: 1. Main-pair coupling relationship analysis module; 2. Loop current type analysis module; 3. Candidate pairing path acquisition module; 4. Target loop closing strategy acquisition module. Detailed Implementation

[0018] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described below are only part of the embodiments of this invention and are used to illustrate the invention, but are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0019] The main-distribution coordinated loop transfer strategy optimization method provided by this invention can be understood as an application that, based on the decoupling analysis of the distribution network loop and the main network operation status during the determination of the traditional distribution network loop transfer strategy, cannot identify the composition and dominant component type of the loop current, and cannot discover the constraint coordination relationship formed by the main-distribution topology coupling between multiple optional loop paths, thus preventing the utilization of the offsetting effect of constraint transmission between paths. This invention proposes a loop path optimization method based on the physical mechanism that pairing different dominant component types can offset constraint transmission (when the dominant component types of the loop current of two loop paths are different, the currents they generate may be opposite in direction or have an angle difference; after vector superposition, the total current amplitude will decrease). This method selects the main-distribution coordinated loop path that accurately reflects the constraint coordination relationship between each loop path, achieving safe and reliable loop transfer to meet the load transfer operation requirements. This method can be applied to various power system operation and management scenarios, such as urban distribution network maintenance and transfer, rapid fault recovery, and load adjustment optimization. When dispatchers need to transfer the load of equipment under maintenance to other power supply paths to ensure power supply continuity, this method can provide a reasonable loop-closing path selection scheme based on the current characteristics of the path to be closed and the coupling relationship between the main and distribution network topologies. The following embodiments will provide a detailed description of the main and distribution network coordinated loop-closing power transfer strategy optimization method of the present invention.

[0020] In one embodiment, such as Figure 1 As shown, a method for optimizing a master-distributor coordinated loop transfer supply strategy is provided, including: S11. Divide the target distribution network into several topological regions, and obtain the main distribution topology coupling relationship according to the connection relationship between each topological region and the main grid power supply node; wherein, the target distribution network can be understood as a distribution network connected to the main grid and requiring loop-connection and transfer operation, and the distribution network includes multiple sub-networks divided by multiple electrical isolation points (network locations where tie switches in the disconnected state are located).

[0021] In this embodiment, the topological regions correspond to sub-networks in the target distribution network. They can be obtained by dividing the network based on the topological coupling relationships of the sub-networks within the target distribution network, or by generating power supply paths between each topological region and the main grid power nodes based on the line connection relationships and switch status information of each topological region, thus constructing the main-distribution topological coupling relationship. Specifically, the steps of dividing the target distribution network into several topological regions and obtaining the main-distribution topological coupling relationship based on the connection relationships between each topological region and the main grid power nodes include: Based on the line connection relationships and switch status information of the target distribution network, each main grid power node is used as the root node, and a breadth-first search algorithm is used to search and group the electrically connected nodes of the target distribution network to obtain multiple distribution sub-networks. Each distribution sub-network is then treated as a topological region. The line connection relationships and switch status information of the target distribution network can be obtained from the regional dispatch control center or the distribution automation master station. The line connection relationships may include the starting node number, ending node number, line length, and conductor type of each line in the target distribution network. The switch status information includes the on / off status, operation time, and location of each tie switch and sectionalizing switch in the target distribution network. It should be noted that the regional dispatch control center includes, but is not limited to, a dispatch server configured with an EMS (Energy Management System), a data acquisition server configured with a SCADA (Supervisory Control and Data Acquisition) system, and a WAMS (Wide Area Measurement System). The main station server of a wide-area measurement system (such as a distribution automation main station) includes, but is not limited to, a single distribution main station server, a server cluster consisting of multiple distribution main station servers, or a cloud-based distribution cloud platform. No specific restrictions are made here.

[0022] In this embodiment, each distribution network can be understood as an electrically connected sub-network identified based on the line connection relationship of the target distribution network. The specific acquisition process may include: marking the lines connected to switches in the closed state in the target distribution network as conduction paths, and marking the locations of switches in the open state as electrical isolation points; starting from any main grid power node in the main grid, performing a breadth-first search along the conduction path, classifying all nodes traversed during the search into the same distribution network, and stopping the search in that direction when an electrical isolation point is encountered during the search; repeating the above search process until all nodes in the target distribution network are classified into a certain distribution network; assigning a topology region number to each distribution network, thus completing the topology region division of the target distribution network. Each distribution network corresponds to a topology region, and each topology region includes, but is not limited to, various 10kV distribution network feeders, 110kV substation buses, distribution transformer areas, switch station areas, user power supply areas, etc.

[0023] This embodiment uses the switch status information of the target distribution network to determine electrical connectivity, which can accurately identify the actual power supply range boundary of the target distribution network under the current operating mode. This not only avoids incorrectly classifying electrically isolated areas into the same topology region, but also ensures that subsequent loop closing operation analysis is performed within the correct electrical boundary by using electrically connected sub-networks as the basis for topology region division, effectively eliminating the problem of loop closing current calculation deviation caused by topology identification errors.

[0024] It should be noted that the breadth-first search algorithm in this embodiment is an algorithm that starts from the root node and traverses the nodes of the tree along the width of the tree. Based on the characteristic of the radial structure of the distribution network during normal operation, in practical applications, when performing breadth-first search from the main grid power nodes, the layer number of each node can be marked. The layer number reflects the distance between the node and the main grid power node. For example, the layer number of the node reached through the main grid power node via two branches is marked as 2, thereby providing a reliable topological basis for subsequent power source tracking and power supply range tracking.

[0025] After dividing the target distribution network into multiple topological regions using the above methods and steps, impedance characteristic analysis can be performed based on the power supply paths between each topological region and the main grid power nodes to establish the equivalent impedance of the power supply paths between each topological region and the main grid power nodes. The specific process for establishing the equivalent impedance of the power supply paths may include: for any topological region, identifying the main grid power node numbers connected to that topological region; and extracting the node power supply paths from the main grid power nodes to each load node within that topological region based on the line connection relationships of the target distribution network. For example, assuming a topological region contains nodes b, c, d, and e, and that region is connected to the main grid... If power node a receives power, there are multiple power supply paths from the main grid power node a to the load nodes within this topology region: a via line 1 to node b, then via line 2 to load node c; a via line 1 to node b, then via line 2 to node c, then via line 3 to load node d; a via line 4 directly to load node e, etc. The resistance and reactance values ​​of each segment of each power supply path are calculated, and these are summed to obtain the equivalent impedance of the power supply path. That is, the impedance of each power supply path from a to c, a to d, a to e, etc., is calculated separately, and then a comprehensive equivalent impedance value representing the power supply characteristics of this topology region is obtained. After obtaining the equivalent impedance of the power supply paths between all topology regions and their corresponding main grid power nodes, a topology region-main grid power node connection relationship table can be constructed. This table records the main grid power node numbers and corresponding equivalent impedance of the power supply paths connected to each topology region, which is used for subsequent construction of the main-distribution topology coupling relationship. It should be noted that the equivalent impedance of the power supply path mentioned above may also include the equivalent impedance of the distribution transformer. For example, when a power supply path of a node passes through a distribution transformer, the short-circuit impedance of the distribution transformer is converted to the corresponding voltage level and then included in the calculation of the equivalent impedance. In this embodiment, the calculation process of the equivalent impedance of each node power supply path in the topology area can be implemented with reference to relevant existing technologies, and will not be described in detail here.

[0026] In this embodiment, the main-distribution topology coupling relationship can be understood as taking into account that when different topological regions in the actual target distribution network perform loop closing operations, the loop closing current is not only affected by the internal impedance of the distribution network, but also constrained by the electrical characteristics of the main grid side. Furthermore, the electrical coupling path formed by different topological regions through the main grid power nodes will also have a significant impact on the loop closing current. To improve the accuracy of the loop closing current calculation, the following method steps are used to analyze the topological coupling relationship formed by the topological regions connected to different main grid power nodes through the main grid, considering the electrical connection relationship between different main grid power nodes within the main grid. The resulting main-distribution topology coupling relationship diagram stores the electrical coupling path parameters between any two topological regions in the entire target distribution network.

[0027] The main grid connection topology and main grid short-circuit capacity of each main grid power node are obtained respectively. Based on the main grid connection topology and the corresponding topology region connection relationship, the main grid electrical coupling path of each topology region pair is determined. The main grid connection topology can be understood as the connection topology of the main grid power node in the main grid, which can be obtained through the topology data of the energy management system, including the connection relationship between the corresponding main grid power node and the main grid substation bus, the voltage level of the connecting line, and the line impedance parameters, etc. The corresponding main grid short-circuit capacity can be obtained based on the short-circuit current calculation results provided by the corresponding main grid dispatching system, including the effective value of the short-circuit current of the corresponding main grid power node under a three-phase short-circuit fault and the short-circuit capacity value of the main grid substation bus connected to the main grid power node, etc.

[0028] In this embodiment, the topology region connection relationship can be understood as the connection relationship between the main network power node and the topology region recorded in the topology region-main network power node connection relationship table constructed when dividing the topology region. Based on the main network connection topology of each main network power node and the related topology region connection relationship, the main network electrical coupling path formed by any two topology regions (a pair of topology regions) through the main network can be determined, thus obtaining the main network electrical coupling path for all pairs of topology regions. Specifically, the process of obtaining the main network electrical coupling path for each pair of topology regions includes: For any pair of topological regions in the target distribution network, identify the main grid power nodes connecting the two topological regions in the pair. Based on the connection topology of the two main grid power nodes in the main grid, identify the connection path between the two main grid power nodes in the main grid. This connection path includes the main grid substation bus that the two main grid power nodes are connected to, and the main grid line connected to the main grid substation bus. The complete path from the main grid power node of one topological region in the pair, through the main grid substation bus, to the main grid power node of the other topological region is defined as the main grid electrical coupling path. The main grid electrical coupling path represents the transmission channel of electrical influence generated by the main grid through the two topological regions during loop closing operation. It should be noted that, in this embodiment, the main grid substation bus refers to the bus of a 500kV or 220kV substation. Multiple main grid power supply nodes may be connected to the same main grid substation bus, thus forming electrical coupling at the main grid level. It is easy to understand that when two distribution network topologies obtain power from different main grid power supply nodes, but these two main grid power supply nodes are connected to the same main grid substation bus within the main grid, the loop closing operation of any topology will cause voltage fluctuations and power flow disturbances to the other topology through the main grid substation bus. This electrical influence transmitted across the main grid is the physical essence of the main grid-distribution topology coupling relationship.

[0029] Based on the main grid electrical coupling path and corresponding main grid short-circuit capacity of each topological region pair, the corresponding coupling path parameters are determined. These coupling path parameters include the total equivalent impedance and the equivalent power supply impedance of the path. The specific acquisition process may include: for a main grid electrical coupling path of a topological region pair, calculating the equivalent impedance of each line and transformer segment along the main grid electrical coupling path, and summing them to obtain the total equivalent impedance of the main grid electrical coupling path; based on the short-circuit capacity of the main grid substation bus in the main grid electrical coupling path, the equivalent power supply impedance of the corresponding main grid substation bus can be obtained using the formula of dividing the square of the rated voltage by the short-circuit capacity, thus obtaining the path equivalent power supply impedance corresponding to the main grid electrical coupling path. Summarizing the total equivalent impedance and the equivalent power supply impedance of each main grid electrical coupling path yields the coupling path parameters in the main-distribution topology coupling relationship. Simultaneously, the short-circuit capacity of the main grid substation bus in the main grid electrical coupling path can also be used to define the power support capacity parameter of the main-distribution topology coupling relationship, characterizing the voltage support strength and the ability to withstand inrush currents provided by the main grid during distribution network loop-closing operations. It should be noted that the coupling path parameters in the main-distribution topology coupling relationship actually determine the magnitude of the impedance that transmits electrical influence between the two topological regions through the main grid. The smaller the impedance, the stronger the coupling. The power supply support capacity parameters can also be used to determine the voltage stability and inrush current withstand capability that the main grid can provide for the distribution network loop operation. The larger the short-circuit capacity, the stronger the power supply support capability, and the smaller the impact of the distribution network loop operation on the main grid.

[0030] Based on each main grid electrical coupling path and the corresponding coupling path parameters, the main distribution topology coupling relationship is generated; wherein, the main distribution topology coupling relationship can be understood as the main distribution topology coupling relationship diagram of the entire distribution network, which includes the main grid electrical coupling path information of each topology region pair stored in the form of a graph structure, and the edges between the two topology regions in each topology region pair in the graph record the corresponding coupling path parameters, which will not be described in detail here.

[0031] This embodiment addresses the shortcomings of traditional distribution network loop-closing power flow calculations, which only consider the internal topology of the distribution network and simplify the main grid as an infinitely large power source, neglecting the impact of the main grid's electrical characteristics on the distribution network's loop-closing operation and resulting in inaccurate loop-closing circuit calculations. By considering that the electrical coupling paths formed by different topological regions through the main grid power source nodes in actual power grid operation have a significant impact on the loop-closing current, this embodiment accurately identifies the main grid and distribution network topology coupling relationship based on the key factors restricting the loop-closing operation across different power source supply regions (the short-circuit capacity and electrical coupling paths on the main grid side), thereby providing a reliable analytical basis for the subsequent accurate calculation of the loop-closing current.

[0032] S12. Obtain the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region to be closed, respectively, and obtain the dominant component type of the closing current for each path to be closed between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor; wherein, the first topological region and the second topological region can be understood as two topological regions within the target distribution network involved in the closing and transfer operation in actual applications, which vary depending on the actual scenario and are not specifically limited here.

[0033] In this embodiment, the first and second voltage phasors can be understood as voltage phasor data collected by measuring devices in the actual first and second topological regions after time alignment processing. These phasors serve as regional reference voltage phasors for subsequent phase angle difference analysis between voltage phasors in the topological regions to identify the dominant component type of the current in the closed-loop path. Considering that in practical applications, different measuring devices in different topological regions may have time deviations in the collected voltage phasor data due to inconsistent time bases, thus affecting the accuracy of voltage phase angle difference analysis (if the time deviation between local clocks reaches ten milliseconds, it will introduce tens of degrees of phase angle error at 50Hz power frequency), to ensure the reliability of voltage phase angle difference calculation and the accuracy of identifying the dominant component type of the current in the closed-loop path, this embodiment preferably performs time synchronization processing on all voltage phasor data collected in the first and second topological regions to be closed before performing voltage phase angle difference analysis. Then, based on the comprehensive analysis of voltage phasor data from multiple key measuring points in the same topological region, the reference voltage phasor value for the corresponding topological region is determined for subsequent phase angle difference analysis of the two ends of the closed-loop path.

[0034] Specifically, the step of obtaining the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region to be merged includes: A first voltage phasor dataset and a second voltage phasor dataset corresponding to the first topological region and the second topological region are obtained respectively. The first voltage phasor dataset can be understood as a dataset composed of node voltage phase information and corresponding sampling times collected by synchronous phasor measurement devices installed at multiple key nodes in the first topological region. Similarly, the second voltage phasor dataset can be understood as a dataset composed of node voltage phase information and corresponding sampling times collected by synchronous phasor measurement devices installed at multiple key nodes in the second topological region. That is, both the first and second voltage phasor datasets include wide-area time-phase data pairs of several measurement points, and each wide-area time-phase data pair includes voltage phasors and corresponding sampling times. It should be noted that each synchronous phasor measurement device in the first and second topological regions can provide a Coordinated Universal Time (UTC) reference based on received GPS or BeiDou satellite timing signals through deployed satellite timing devices, and also provide a reliable time reference for the comparative analysis of voltage phasor data from different topological regions.

[0035] Wide-area temporal phase data with the same sampling time in both the first and second voltage phasor datasets are grouped into a synchronized phasor data group, and the sampling time of this synchronized phasor data group is used as the target sampling time. In practical applications, to ensure the time comparability of voltage phasor data in the two topological regions, it is necessary to uniformly process the wide-area temporal phase data in the first and second voltage phasor datasets based on the voltage phasor's time label (sampling time). Considering that in practical applications, when time synchronization services are provided based on a unified satellite timing device, most measuring devices in the first and second topological regions can maintain time synchronization, to improve the efficiency of data synchronization analysis and processing, this embodiment preferably first selects wide-area temporal phase data with completely identical time labels in both the first and second voltage phasor datasets and groups them into a synchronized phasor data group, which serves as the main data basis for subsequently determining the first and second voltage phasors. It should be noted that, to facilitate the subsequent use of the obtained time synchronization data from different topological regions for voltage phasor calculations in their respective topological regions, a corresponding topological region code can be added when grouping each wide-area temporal phase data into the synchronized phasor data group.

[0036] The deviation between the sampling time and the target sampling time of each of the wide-area time-phase data pairs not included in the synchronization phasor data group is calculated. If the deviation is less than a preset synchronization threshold, the corresponding wide-area time-phase data pair is added to the synchronization phasor data group. The preset synchronization threshold can be understood as a preset allowable range of time deviation between measuring devices, which can be determined based on the power grid frequency and phase angle error requirements. For example, when the power grid frequency is 50Hz and the phase angle error is required to be no more than 1 degree, the preset synchronization threshold can be set to 55.6 microseconds, because the period of a 50Hz power grid is 20 milliseconds, and 1 degree phase angle corresponds to a time deviation of 55.6 microseconds. In practical applications, in principle, the data in the synchronization phasor data group obtained in the previous step can be directly used to analyze and determine the first and second voltage phasors. However, in order to maximize the comprehensiveness of the analyzed data and ensure the reliability of the regional voltage phasor generation, this embodiment preferably uses a preset synchronization threshold to filter out a portion of the data with time deviations within the allowable range, further expanding the synchronization phasor data group.

[0037] The synchronization phasor data group is divided into a first synchronization data group and a second synchronization data group according to its topological region. The voltage phasors of all corresponding measurement points in the first synchronization data group and the second synchronization data group are weighted and averaged to obtain the corresponding first voltage phasor and second voltage phasor. The first synchronization data group can be understood as the time-synchronized wide-area phase data of the topological region numbered first in the synchronization phasor data group, and the second synchronization data group can be understood as the time-synchronized wide-area phase data of the topological region numbered second in the synchronization phasor data group. In practical applications, when weighted averaging the voltage phasors of all measurement points in the first synchronous data group, the weight coefficients corresponding to the voltage vectors of each measurement point can be determined based on the load power ratio of the measurement point (the proportion of the load power of the measurement point to the total load power of the topology area). The load power of each measurement point can be obtained through the monitoring terminal of the distribution transformer deployed in the topology area, which will not be described in detail here. That is, the voltage phasors of multiple key measurement points in the first topology area are weighted according to the load weight (load power ratio) of the measurement points to obtain the first voltage phasor corresponding to the first topology area. Similarly, the second voltage phasor corresponding to the second topology area can be calculated.

[0038] This embodiment effectively solves the problem that the voltage phasor data of multiple measurement points within the collected topological region are easily affected by local load fluctuations and cannot fully reflect the overall voltage level of the topological region by performing time synchronization processing and then weighted averaging. By introducing load weights to comprehensively analyze the voltage status of each key node within the topological region, a more representative voltage phasor of the topological region can be obtained, thus providing reliable data support for the subsequent analysis of the dominant component type of the loop current in the path to be closed.

[0039] like Figure 2 As shown, the topology network applicable to the main-distribution coordinated loop-to-supply strategy optimization provided in this embodiment may include a main network and multiple topology regions (e.g., topology region A, topology region B, topology region C, topology region D, and topology region E), and the main network includes a PMU (Phasor Measurement Unit) connected to a common bus. The unit consists of a device and multiple substations (e.g., 500kV substation 1 and 500kV substation 2) and can communicate with a regional dispatch control center with a distribution automation master station. Each topology region includes low-voltage transformers (e.g., 10kV transformers). Each substation is electrically connected to the corresponding topology region through a power supply path. The topology regions are connected by loop-to-close paths (e.g., there is a loop-to-close path L1 between topology region A and topology region B, a loop-to-close path L2 between topology region C and topology region D, and a loop-to-close path L3 between topology region B and topology region E). In this embodiment, each loop-to-close path between the first and second topology regions corresponds to a set of daisy-chain feeders between the first and second topology regions. Each set of daisy-chain feeders is a loop-to-close path that needs to be analyzed in this embodiment. The two end nodes of each loop-to-close path are distributed in the two topology regions connected by the path. The end node is defined as the node location of the tie switch. The dominant component type of the loop current in the path to be closed can be understood as the current type determined by comprehensively analyzing the dominant components of the loop current based on the voltage phasors and load power corresponding to the two end nodes of the path to be closed. This can include a phase angle difference dominant type with a large voltage phase angle difference between the two ends of the loop, a load difference dominant type with a large load power difference, and a mixed dominant type where the voltage phase angle difference and load power difference are close. Specifically, the step of obtaining the dominant component type of the loop current for each path to be closed between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor includes: Based on the first voltage phasor and the second voltage phasor, the phase angle difference of the end nodes of each of the paths to be closed is calculated, and the corresponding phase angle difference driving current component is calculated based on each of the end node phase angle differences. The end node phase angle difference can be understood as the difference between the phase angle of the first voltage phasor and the phase angle of the second voltage phasor. It should be noted that the phase angle of the voltage phasor is the angle of the voltage phasor in the complex plane, with the positive direction of the horizontal real axis as the zero-degree reference direction and the counterclockwise direction as positive. The specific extraction can be achieved using relevant existing technologies, which will not be detailed here. The corresponding phase angle difference can reflect the time lead or lag relationship of the voltage phasors of the two end nodes of the path to be closed.

[0040] In practical applications, voltage phase angle difference is the fundamental reason driving active power flow. Based on power system flow calculation theory, when there is a voltage phase angle difference between the two ends of the loop to be closed, active power transmission will occur on the loop to be closed, and the power transmission direction is from the end with the leading phase angle to the end with the lagging phase angle. Based on the equivalent impedance of the loop to be closed (including the resistance and reactance of the loop line), the magnitude of the voltage phasors of the two end nodes, and the phase angle difference, the current component driven only by the phase angle difference can be calculated as the phase angle difference driving current component. It should be noted that the phase angle difference driving current component can be calculated by simplifying the two ends of the loop to be closed into two voltage sources connected by the equivalent impedance of the loop to be closed under the influence of load power difference, based on the Thevenin equivalent circuit model, and using the voltage magnitude of the voltage source as the magnitude of the voltage phasor at the two ends of the loop to be closed, and the phase difference of the voltage source as the phase angle difference, to analyze the power transmission relationship between the two voltage sources. This will not be elaborated here.

[0041] Obtain the load power difference of each of the end nodes of the path to be closed, and calculate the corresponding load difference driving current component based on the load power difference of each end node; wherein, the load power difference of the end node can be understood as the difference in the active power of the load at the two end nodes of the path to be closed, and the active power of the load at the end node can still be obtained by the aforementioned prior art. In practical applications, the load power difference at the end nodes is also a reason for driving active power flow, and it will also generate active power transmission on the path to be closed. Based on the equivalent impedance of the path to be closed and the load power difference at the end nodes, the current component driven only by the load power difference can be calculated as the load difference driving current component. It should be noted that the load difference driving current component can be obtained by using the power flow distribution principle under the influence of voltage phase angle difference, which equates the load power difference to the power injection at one end of the path to be closed, and then transmits it to the other end through the equivalent impedance of the path to be closed. This will not be elaborated here.

[0042] Considering that the phase angle difference driving current component and the load difference driving current component are two independent components of the loop current, and that they have different amplitudes and phases in the complex plane, and that the phase angle difference driving current component is mainly determined by the phase angle difference of the end nodes of the path to be closed and is independent of the load distribution at both ends, while the load difference driving current component is mainly determined by the load power difference of the end nodes of the path to be closed and is independent of the voltage phase difference at both ends, the following method steps can be used to independently analyze the contribution of the two current components to the loop current in the complex plane, so as to accurately identify the dominant component of the loop current.

[0043] Each of the aforementioned loop paths to be closed is constructed with its equivalent impedance as a reference, forming a corresponding complex plane rectangular coordinate system. The corresponding phase angle difference driving current component and load difference driving current component are then mapped to the complex plane rectangular coordinate system to obtain the corresponding complex plane information. The complex plane rectangular coordinate system can be understood as a rectangular coordinate system established in the complex plane according to the principle that the real axis direction is consistent with the direction of the equivalent impedance of the loop path to be closed in the complex plane and the imaginary axis direction is perpendicular to the real axis direction. The direction of the equivalent impedance of the loop path to be closed in the complex plane is determined by the resistance component and the reactance component of the equivalent impedance. The argument of the equivalent impedance is equal to the quotient of the arctangent function acting on the reactance component divided by the resistance component.

[0044] The process of mapping the phase angle difference drive current component and the load difference drive current component to the complex plane rectangular coordinate system includes: representing the phase angle difference drive current component in complex form, where the real part of the complex number is the projection of the phase angle difference drive current component onto the real axis, and the imaginary part of the complex number is the projection of the phase angle difference drive current component onto the imaginary axis; representing the load difference drive current component in complex form, where the real part of the complex number is the projection of the load difference drive current component onto the real axis, and the imaginary part of the complex number is the projection of the load difference drive current component onto the imaginary axis; after the mapping is completed, the phase angle difference drive current component and the load difference drive current component form corresponding coordinates in the complex plane rectangular coordinate system. The vectors, where the length of the vector represents the magnitude of the current component and the direction of the vector represents the phase of the current component, provide complex plane information including the first complex module length, the first complex argument, the second complex module length, and the second complex argument. The first and second complex modules are the lengths of the vectors corresponding to the phase difference driving current component and the load difference driving current component, respectively, and are equal to the square root of the sum of the squares of their complex real parts and the squares of their imaginary parts. The first and second complex arguments are the angles between the vectors corresponding to the phase difference driving current component and the load difference driving current component and the positive direction of the real axis, respectively, and are obtained by calculating the quotient of the complex imaginary part divided by the real part using the arctangent function.

[0045] In this embodiment, under the complex plane rectangular coordinate system, the direction of the equivalent impedance of the path to be closed corresponds to the positive direction of the real axis. The projection of the current component along the real axis represents the current component in phase with the equivalent impedance, and the projection of the current component along the imaginary axis represents the current component orthogonal to the phase of the equivalent impedance. Establishing a complex plane rectangular coordinate system with the equivalent impedance of the path to be closed as a reference makes the phase relationship between the phase difference driving current component and the load difference driving current component more intuitive.

[0046] Based on the complex plane information of each of the proposed loop-closing paths, the magnitude and phase relationships are analyzed to determine the corresponding dominant component type of the loop-closing current. The magnitude relationship can be understood as the relationship between the first and second complex magnitudes. The phase relationship can be understood as the phase angle between the phase difference-driven current component and the load difference-driven current component in the complex plane, which can be represented by the difference between the first and second complex arguments. The phase angle reflects the degree of phase difference between the two current components; a phase angle close to zero indicates that the two current components are nearly in phase, and a phase angle close to 180 degrees indicates that the two current components are nearly out of phase. It should be noted that in practical applications, the phase relationship can also be identified by calculating the dot product of the two current component vectors. For example, a dot product greater than zero indicates that the two current components have components in the same direction in the complex plane, and a dot product less than zero indicates that the two current components have components in opposite directions in the complex plane. Alternatively, the cross product of the two current component vectors can be calculated, with the sign of the cross product reflecting the rotational relationship between the two current components in the complex plane.

[0047] In this embodiment, the dominant component type of the closing current can be understood as the current type obtained by determining the contribution of the phase angle difference driving current component and the load difference driving current component in the closing current based on the magnitude and phase relationship of the phase angle difference driving current component vector and the load difference driving current component vector. Specifically, the step of determining the corresponding dominant component type of the closing current by analyzing the magnitude and phase relationship based on the complex plane information of each of the paths to be closed includes: When the ratio of the first complex module length to the second complex module length of the loop to be closed is greater than a preset discrimination threshold, the corresponding loop current dominant component type is marked as phase angle difference dominant type. The preset discrimination threshold can be understood as a preset proportional relationship threshold used to determine whether a certain current component dominates the loop current. It can be set based on actual application requirements. For example, the preset discrimination threshold can be set to 1.5, meaning that when the first complex module length is 1.5 times the second complex module length, the phase angle difference driving current component in the loop current is considered to contribute significantly, and the loop current dominant component type is marked as phase angle difference dominant type. The loop current of the phase angle difference dominant type path mainly originates from the voltage phase angle difference between the two ends of the loop to be closed. Adjusting the voltage phase angle through measures such as main transformer tap adjustment and capacitor / reactor switching can effectively reduce the loop current of the phase angle difference dominant type path.

[0048] When the ratio of the first complex modulus to the second complex modulus of the path to be closed is less than the reciprocal of the preset discrimination threshold, the corresponding dominant component type of the closed current is marked as load difference dominant type; that is, if the ratio of the complex modulus corresponding to the phase angle difference driving current component vector to the complex modulus of the load difference driving current component vector is less than the reciprocal of the preset discrimination threshold, it is considered that the load difference driving current component contributes significantly to the closed current, and the dominant component type of the closed current is marked as load difference dominant type; the closed current of the load difference dominant type path mainly comes from the load power difference at both ends of the path to be closed. By balancing the load distribution at both ends through load transfer, distributed power source regulation and other measures, the closed current of the load difference dominant type path can be effectively reduced.

[0049] When the ratio of the first complex modulus to the second complex modulus of the path to be closed in the loop falls within a preset ratio range, the difference between the corresponding first complex argument and the second complex argument is obtained as the corresponding phase angle. Based on the relationship between the phase angle and the preset phase coordination threshold, the type of the dominant component of the closed loop current is determined. The preset ratio range can be understood as a ratio range determined by using a preset discrimination threshold and its reciprocal as the upper and lower limits, respectively. Within this range, the amplitude difference between the two current components is not significant, and the type of dominant component cannot be determined solely by the amplitude. Considering that when the first complex module length and the second complex module length are similar and the phase angle is small, the two current components will be enhanced by superposition in the complex plane, resulting in a large loop current. However, when the first complex module length and the second complex module length are similar and the phase angle is close to 180 degrees, the two current components will cancel each other in the complex plane, resulting in a small loop current. In this embodiment, it is preferable to further determine the dominant component type of the loop current based on the phase angle when the ratio of the first complex module length to the second complex module length is within a preset ratio range. That is, when the amplitudes of the two current components are close, the phase relationship becomes the key factor determining the characteristics of the loop current. The corresponding preset phase coordination threshold can be understood as a phase angle threshold used to determine whether the two current components are coordinated in phase. For example, when the preset phase coordination threshold is set to 30 degrees, it means that when the phase angle between the two current components is less than 30 degrees, the two current components are basically coordinated in phase.

[0050] Specifically, the step of determining the type of dominant component of the closed-loop current based on the relationship between the phase angle and the preset phase coordination threshold includes: If the phase angle is less than the preset phase coordination threshold, the type of the dominant component of the loop current is marked as mixed dominant. Otherwise, the vector and argument of the phase angle difference driving current component and the load difference driving current component are obtained. That is, if the phase angle is greater than or equal to the preset phase coordination threshold, the contribution of the two current components is considered to be similar, and they are directly marked as mixed dominant. At the same time, considering that when the phase angle of the current components is small, the two current components will superimpose and the loop current will be large. At this time, the dominant direction of the synthesized vector determines the preferred direction of the current limiting measure. When the phase angle is large, the two current components will cancel each other out and the loop current will be small. At this time, the current limiting requirement is not urgent or it is necessary to consider both current limiting measures. In this embodiment, preferably, when the phase angle of the two current components is less than the preset phase coordination threshold, the type is further determined by analyzing the closeness of the vector sum of the two current components to the argument of the two current components. It should be noted that the vector and the argument are the vector and the corresponding argument obtained by the synergistic superposition of the phase difference driving current component and the load difference driving current component in the complex plane. For specific calculations, please refer to relevant existing technologies, which will not be detailed here.

[0051] Calculate the first and second argument deviations corresponding to the vector and argument and the first and second complex arguments, respectively; wherein the first argument deviation is the difference between the first complex argument and the vector and argument, and the second argument deviation is the difference between the second complex argument and the vector and argument.

[0052] When the first phase angle deviation is less than the second phase angle deviation, the type of the dominant component of the closed loop current is marked as the phase angle difference dominant type; that is, when the phase angle of the vector sum is closer to the phase angle difference driving current component, the type of the dominant component of the closed loop current is determined to be the phase angle difference dominant type.

[0053] When the first phase deviation is greater than the second phase deviation, the type of the closed loop current dominant component is marked as load difference dominant type; that is, when the phase of the vector sum is closer to the phase of the load difference driving current component, the type of the closed loop current dominant component is determined to be load difference dominant type.

[0054] The loop-closing path current dominant component type identification mechanism provided in this embodiment, which combines wide-area time synchronization technology with complex plane vector analysis method, can not only solve the problem of insufficient current limiting measures due to the lack of differentiation of the dominant component of the loop-closing current in existing loop-closing operations, but also provide a reliable classification basis for subsequent determination of cross-regional loop-closing pairing paths based on the analysis of the loop-closing current vector cancellation effect. This allows the pairing paths to complement each other in terms of dominant component type, thereby meeting the application requirements of current vector cancellation and reducing the total current of the paired loop closure.

[0055] S13. Based on the criterion that allows pairing of different dominant components of the loop current, all the loop paths to be closed are paired and combined to generate a candidate pairing path set; wherein, the criterion that allows pairing of different dominant components of the loop current is based on the fact that the phase of the loop current of the phase angle difference dominant type loop path and the load difference dominant type loop path is determined by the voltage phase angle difference and the load power difference, respectively. The electrical influence directions generated by the two at the main grid power node are often opposite. Moreover, by selecting paths with different dominant component types for pairing and loop closing, the reverse traction effect formed by the constraint transmission vector of the two paths in the complex plane can be used to make the total current of the paired loop closing less than the single-path loop closing current, thus realizing the characteristic of vector cancellation effect.

[0056] In this embodiment, the process of obtaining the candidate pairing path set is as follows: among all the loop-to-close paths between the first and second topological regions, the loop-to-close paths with the dominant loop current type being phase angle difference dominant and load difference dominant are respectively divided into phase angle difference dominant loop-to-close path group and load difference dominant loop-to-close path group; the loop-to-close paths with different dominant loop current types in the phase angle difference dominant loop-to-close path group and the load difference dominant loop-to-close path group are paired and combined in sequence to obtain all possible candidate pairing paths, that is, to form the required candidate pairing path set.

[0057] S14. Based on the main-supplier topology coupling relationship, determine the constraint transfer relationship matrix of the path to be closed, and based on the constraint transfer relationship matrix of the path to be closed, perform a pairing path loop current vector cancellation effect analysis on the candidate pairing path set to obtain the target loop-closing transfer strategy; wherein, the constraint transfer relationship matrix of the path to be closed can be understood as a matrix including the bidirectional path constraint transfer vector between any two paths to be closed, the rows and columns of the matrix represent different paths to be closed, and the matrix elements are the influence of the loop-closing operation of one path on the loop current of another path to be closed; specifically, the step of determining the constraint transfer relationship matrix of the path to be closed based on the main-supplier topology coupling relationship includes: Based on the main-distribution topology coupling relationship, the common influence node of each pair of paths to be closed is obtained, and the corresponding equivalent circuit model is constructed using the common influence node as the observation point. The equivalent circuit model includes an equivalent voltage source and an equivalent impedance network. The common influence node can be understood as the main grid substation bus that the main grid power supply nodes of the two paths to be closed in the pair are connected to in the main grid, and can be obtained through the main-distribution topology coupling relationship. In this embodiment, the common influence node is the key node for the electrical coupling of the two paths to be closed through the main grid. Considering that the closing operation of any path to be closed will change the voltage and power flow of the common influence node, and thus affect the closing conditions of the other path to be closed, the equivalent circuit model can be constructed using the common influence node as the observation point to analyze the influence relationship of the closing operation between the paths to be closed. The specific process of constructing the equivalent circuit model may include: according to Thevenin's theorem, the main network portion other than the common influence node is equivalent to an equivalent voltage source, and the voltage amplitude and phase of the equivalent voltage source are determined by the voltage state of the common influence node before loop closure; the electrical path from the common influence node to each endpoint of the path to be closed is equivalent to an equivalent impedance network, and the equivalent impedance network includes the distribution network impedance from the main network power node to the endpoint of the path to be closed, and the main network impedance from the common influence node to the main network power node; it should be noted that the actual construction details of the equivalent circuit model can be implemented with reference to relevant existing technologies, and will not be detailed here.

[0058] Based on the equivalent circuit model, the influence of one path performing a loop-closing operation on the loop-closing current vector of the other path in each of the proposed loop-closing path pairs is determined, and the corresponding path constraint transfer vector is obtained. Based on the path constraint transfer vector, the constraint transfer relationship of the proposed loop-closing path pairs is constructed. The path constraint transfer vector can be understood as the influence of the phasor changes of the equivalent voltage source and the topological changes of the equivalent impedance network in the equivalent circuit model of one proposed loop-closing path on the loop-closing current vector after the loop-closing operation is transferred to the equivalent circuit model of the other proposed loop-closing path. The specific process of obtaining the path constraint transfer vector includes: 1) Calculate the current change of the first path in the path pair to be closed before and after closure, passing through the common affected node; calculate the voltage change of the common affected node based on the current change of the first path and the equivalent impedance network, and use the voltage change as the phasor change of the equivalent voltage source; obtain the topology change of the distribution network caused by the closure operation of the first path, and use the adjustment of the equivalent impedance network structure caused by the topology change as the topology change of the equivalent impedance network; it should be noted that when a path to be closed is closed, power is injected or extracted into the common affected node, causing the voltage of the common affected node to drop or rise. At the same time, the closure operation changes the open-loop structure of the distribution network to a closed-loop structure, making the topology of the equivalent impedance network change from radial to ring.

[0059] 2) Based on the phasor changes of the equivalent voltage sources and the topology changes of the equivalent impedance network in the equivalent circuit model corresponding to the first path to be closed in the current loop-closing operation, update the equivalent circuit model corresponding to the second path to be closed in the loop-closing path pair. In practical applications, the original voltage phasor of the equivalent voltage source of the first path to be closed and the phasor changes of the equivalent voltage source can be vector-superimposed to obtain the new voltage phasor of the common influence node after the first path to be closed is closed. The new voltage phasor is used to update the equivalent voltage source in the equivalent circuit model of the second path to be closed. Then, based on the topology changes of the equivalent impedance network of the first path to be closed, the equivalent impedance from the common influence node to the endpoint of the second path to be closed is recalculated. The recalculated equivalent impedance is used to update the equivalent impedance network in the equivalent circuit model corresponding to the second path to be closed.

[0060] 3) Based on the updated equivalent circuit model corresponding to the second loop path, recalculate the loop current vector of the second loop path after the first loop path is closed, and use it as the recalculated loop current vector; obtain the loop current vector of the second loop path when it is independently closed before the first loop path is closed, and use it as the initially calculated loop current vector of the second loop path; subtract the initially calculated loop current vector from the recalculated loop current vector in the complex plane, and use the difference vector as the path constraint transfer vector of the first loop path to the second loop path. It should be noted that the path constraint transfer vector characterizes the influence of the closing operation of the first loop to be closed on the closing current of the second loop to be closed. The magnitude of the path constraint transfer vector reflects the degree of influence, and the phase of the path constraint transfer vector reflects the direction of influence. A positive value of the path constraint transfer vector indicates that the closing of the first loop to be closed increases the closing current of the second loop to be closed, while a negative value indicates that it decreases the closing current. The phase relationship between the path constraint transfer vector and the initial closing current vector of the second loop to be closed determines whether the constraint transfer effect exacerbates or mitigates the closing impact.

[0061] Based on the above method steps, the path constraint transfer vector between the second path to be merged and the second path to be merged in the same path pair can also be obtained, which will not be elaborated here. After obtaining the bidirectional path constraint transfer vector between the two paths to be merged in the same path pair, an association mapping can be established based on the first path to be merged, the second path to be merged, and the corresponding two path constraint transfer vectors to form a constraint transfer relationship. This constraint transfer relationship records the first path to be merged, the second path to be merged, the magnitude and phase of the two path constraint transfer vectors, and the corresponding common influence node number in the path pair.

[0062] Based on the constraint transfer relationships of all the proposed loop path pairs, a constraint transfer relationship matrix for the proposed loop paths is generated. That is, after performing pairwise combination analysis on all proposed loop paths between the first and second topological regions of the proposed loop to obtain the constraint transfer relationships of all possible proposed loop path pairs, the constraint transfer relationships of all proposed loop path pairs can be summarized and stored to obtain a data set including the mutual constraint relationships between all proposed loop paths, which can be used for subsequent analysis of the loop current vector cancellation effect.

[0063] This embodiment identifies common influencing nodes formed through the main network based on the coupling relationship between the main and distribution topologies. It establishes the constraint transfer relationship between the paths to be closed by constructing an equivalent circuit model to calculate the constraint transfer vector generated by one path when closing the loop on another path. This effectively solves the application limitations of existing technologies that decouple the distribution network from the main network, and realizes the collaborative analysis of the distribution network loop closing operation and the main network operation status. While reliably quantifying the constraint collaboration relationship formed between the paths to be closed due to the coupling between the main and distribution topologies, it provides strong technical support for improving the reliability of the loop closing operation by considering the constraint transfer relationship of the paths to be closed.

[0064] The pairing path loop current vector cancellation effect analysis in this embodiment can be understood as a process of determining whether there is a current vector cancellation effect in each group of candidate pairing paths in the candidate pairing path set based on the constraint transmission relationship of the path to be closed. To ensure the efficiency of the analysis, this embodiment preferably performs unidirectional cancellation effect analysis on the two paths to be closed in each group of candidate pairing paths. Specifically, the step of performing pairing path loop current vector cancellation effect analysis on the candidate pairing path set according to the constraint transmission relationship matrix of the path to be closed, and obtaining the target cross-domain pairing path includes: Based on the constraint transfer relationship matrix of the path to be merged, obtain the constraint transfer vector to be analyzed for each group of candidate paired paths; wherein, the constraint transfer vector to be analyzed can be understood as any one of the path constraint transfer vectors in the constraint transfer relationship matrix of the path to be merged that matches the constraint transfer relationship of the two path to be merged in the candidate paired paths.

[0065] Based on the first closed-loop current vector, the second closed-loop current vector, and the constraint transfer vector to be analyzed corresponding to each group of candidate pairing paths, a corresponding closed-loop current vector triangle is constructed in the complex plane. The closed-loop current vector triangle is understood as a closed or approximately closed geometric figure formed by connecting the first closed-loop current vector, the second closed-loop current vector, and the constraint transfer vector to be analyzed end-to-end in the complex plane, based on the principle of vector superposition. The shape of the vector triangle reflects the configuration relationship of the three vectors. The specific construction process includes: obtaining the closed-loop current vector of the first closed-loop path in the candidate pairing paths as the first closed-loop current vector, and obtaining the candidate pairing paths... The loop current vector of the second loop path is taken as the second loop current vector. Assuming that the constraint transfer vector to be analyzed is the path constraint transfer vector of the first loop path to the second loop path, the first loop current vector is drawn in the complex plane with the origin as the starting point and the endpoint of the first loop current vector is recorded. The constraint transfer vector to be analyzed is drawn with the endpoint of the first loop current vector as the starting point and the endpoint of the constraint transfer vector to be analyzed is recorded. Then the second loop current vector is drawn with the origin as the starting point. Ideally, the endpoint of the second loop current vector coincides with or is close to the endpoint of the constraint transfer vector to be analyzed. The three vectors form the required loop current vector triangle.

[0066] It should be noted that in this embodiment, both the first and second closed-loop current vectors can be calculated using the Thevenin equivalent circuit model or the power flow distribution principle (the closed-loop path dominated by phase angle difference is calculated using the Thevenin equivalent circuit model, and the closed-loop path dominated by load difference is calculated based on the power flow distribution principle). When constructing the closed-loop current vector triangle, if the constraint transfer vector to be analyzed is the path constraint transfer vector of the second closed-loop path to the first closed-loop path, then the second closed-loop current vector needs to be drawn in the complex plane with the origin as the starting point and the endpoint of the second closed-loop current vector needs to be recorded. After drawing the constraint transfer vector to be analyzed with the endpoint of the second closed-loop current vector as the starting point and recording the endpoint of the constraint transfer vector to be analyzed, the first closed-loop current vector is drawn again with the origin as the starting point.

[0067] Morphological analysis is performed on each of the closed-loop current vector triangles to obtain their corresponding geometric features. Morphological analysis can be understood as analyzing the magnitudes of the three sides and the three interior angles of the closed-loop current vector triangle to obtain comprehensive parameters describing the shape and angular distribution of the vector triangle: the magnitudes of the first closed-loop current vector, the second closed-loop current vector, and the constraint transfer vector to be analyzed are calculated as the magnitudes of the three sides of the closed-loop current vector triangle; the angles between the first closed-loop current vector and the constraint transfer vector to be analyzed, the angle between the constraint transfer vector to be analyzed and the second closed-loop current vector, and the angle between the second closed-loop current vector and the first closed-loop current vector are calculated. The included angles between the current vectors serve as the three interior angles of the closed-loop current vector triangle. The proportional relationship between the magnitudes of the three vectors determines whether the vector triangle is an equilateral, isosceles, or irregular triangle. The three interior angles determine whether the vector triangle contains obtuse angles, right angles, or consists entirely of acute angles. The corresponding geometric features can be understood as parameters used in the comprehensive parameters for analyzing the cancellation effect of the closed-loop current vectors. These include the first and second cosine values ​​of the included angle between the constraint transfer vector to be analyzed and the first and second closed-loop current vectors, respectively. These values ​​determine the effect of the constraint transfer vector to be analyzed on the two closed-loop paths.

[0068] In practical applications, the process of obtaining the first and second cosine values ​​of the included angle may include: representing the first closed-loop current vector and the constraint transfer vector to be analyzed as complex numbers, and extracting the real and imaginary parts of the two complex numbers; calculating the vector dot product of the first closed-loop current vector and the constraint transfer vector to be analyzed, the vector dot product being equal to the real part of the first closed-loop current vector multiplied by the real part of the constraint transfer vector to be analyzed, plus the imaginary part of the first closed-loop current vector multiplied by the imaginary part of the constraint transfer vector to be analyzed; calculating the product of the magnitude of the first closed-loop current vector and the magnitude of the constraint transfer vector to be analyzed; dividing the vector dot product by the magnitude product to obtain the first cosine value of the included angle; similarly, the second cosine value of the included angle between the second closed-loop current vector and the constraint transfer vector to be analyzed can be obtained. It should be noted that the vector dot product is a scalar operation between two vectors in mathematics. The sign of the dot product reflects whether the angle between the two vectors is acute or obtuse. The cosine of the angle is the cosine function value of the angle. A positive cosine indicates an acute angle, a negative cosine indicates an obtuse angle, and a zero cosine indicates a right angle. In other words, the sign of the cosine directly reflects the direction of the influence of the constraint transfer vector on the loop current vector: a positive cosine value results in the constraint transfer vector and the loop current vector having roughly the same direction, producing a reinforcing effect; a negative cosine value results in the constraint transfer vector and the loop current vector having roughly the opposite direction, producing a reverse pulling effect.

[0069] When the first and second cosine values ​​of the candidate pairing paths in each group are both negative, it is determined that the corresponding candidate pairing paths have a loop current vector cancellation effect, and the candidate pairing paths are added to the cross-domain pairing path set. The loop current vector cancellation effect can be understood as the constraint transfer vectors of the two loop paths to be analyzed causing the loop currents of the two paths to form a phase-opposing configuration in the complex plane, which has a reverse pulling effect on both the first and second loop current vectors, thereby canceling out part of the current amplitude when the vectors are superimposed. When both the first and second cosine values ​​of the included angle are negative, it indicates that the angles between the constraint transmission vector to be analyzed and the first and second loop current vectors are both obtuse. In this case, the constraint transmission vector to be analyzed simultaneously reduces the amplitude or changes the phase of the first and second loop current vectors. This satisfies the condition that the loop closure of the second loop path will reduce the loop current of the first loop path, and the loop closure of the first loop path will reduce the loop current of the second loop path. That is, the two loop paths to be closed in the candidate pairing path will produce a mutually inhibiting vector cancellation effect when they are paired and closed, which can make the total loop current of the paired path less than the single-path loop current. The candidate paired path can be added to the cross-domain paired path set as the data basis for subsequent optimal paired path screening.

[0070] This embodiment employs a mechanism based on the constraint propagation relationship between loop-closing paths to analyze the loop-closing current cancellation effect of candidate paired paths generated from pairing paths with different dominant loop-closing current types, thereby obtaining a cross-domain paired path set. This fully utilizes the vector cancellation effect of the constraint propagation between paths to reduce the total amplitude of the loop-closing current, effectively exploring the optimization space of the loop-closing current and providing a reliable guarantee for ensuring the rationality and reliability of the final loop-closing current calculation. It should be noted that, considering that the cross-domain paired path set obtained through the above method may simultaneously include multiple sets of cross-region paired paths that satisfy the vector cancellation effect condition, while in practical applications a set of optimal paired paths that meet the loop-closing transfer execution effect is required, further screening based on the following steps is necessary.

[0071] According to the preset pairing path filtering strategy, the cross-domain pairing path set is subjected to path filtering analysis, and the target loop-connection transfer strategy is generated based on the obtained optimal pairing path. The preset pairing path filtering strategy can be understood as a filtering mechanism that selects the optimal pairing path that satisfies the loop-connection transfer execution effect from the cross-domain pairing path set that meets the vector cancellation effect requirement. In order to meet diverse application requirements, this embodiment preferably sets the preset pairing path filtering strategy to include at least one of the minimum loop-connection current strategy and the maximum cancellation effect strategy. That is, the minimum loop-connection current strategy or the maximum cancellation effect strategy can be used alone, or the minimum loop-connection current strategy and the maximum cancellation effect strategy can be combined.

[0072] The minimum loop-closing current strategy in this embodiment can be understood as a selection strategy that aims to minimize the total current flowing through the common affected nodes after pairing and loop-closing, thereby minimizing the impact of the loop-closing operation on the main network. In practical applications, for each pair of cross-domain pairing paths in the cross-domain pairing path set, the corresponding pairing and loop-closing total current vector can be calculated. The magnitudes of the pairing and loop-closing total current vectors of each pair of cross-domain pairing paths are compared, and the cross-domain pairing path with the smallest magnitude of the pairing and loop-closing total current vector is selected as the optimal pairing path for generating the target loop-closing power transfer strategy. That is, when the preset pairing path selection strategy is the minimum loop-closing current strategy, the target loop-closing power transfer strategy is generated according to the cross-domain pairing path corresponding to the minimum magnitude loop-closing total current vector in the cross-domain pairing path set. The calculation steps of the loop-closing total current vector of each pair of cross-domain pairing paths in the cross-domain pairing path set include: Obtain the first loop current vector corresponding to the first loop-closing path and the second loop current vector corresponding to the second loop-closing path in each group of cross-domain pairing paths; wherein, the acquisition of the first loop current vector and the second loop current vector can be referred to the previous description, and will not be repeated here; Based on the constraint transfer relationship matrix of the path to be closed, the first constraint transfer vector generated by the first closed path on the second closed path when performing the closed operation in each group of cross-domain paired paths, and the second constraint transfer vector generated by the second closed path on the first closed path when performing the closed operation; wherein, when the first constraint transfer vector and the second constraint transfer vector perform the closed operation according to the cross-domain paired path, the constraint transfer effect will be applied to the two paths to be closed in the cross-domain paired path simultaneously; based on this, when calculating the total closed current vector of the paired closed path, the influence of the first constraint transfer vector and the second constraint transfer vector on their respective closed currents needs to be considered simultaneously.

[0073] The first loop-closing current vector, the second loop-closing current vector, the first constraint transfer vector, and the second constraint transfer vector corresponding to each group of cross-domain paired paths are vector superimposed in the complex plane to obtain the corresponding total loop-closing current vector. The total loop-closing current vector can be understood as the combined current flowing through the common influence node of the two paths to be closed simultaneously in the cross-domain paired paths, reflecting the total current amplitude and phase passing through the common influence node when the two paths to be closed are paired and closed. The amplitude determines the impact of the pairing and closing operation on the main network. The total loop-closing current vector can be obtained by combining the first loop-closing current vector, the second loop-closing current vector, and the second constraint transfer vector in the complex plane. The current vector, the first constraint transfer vector, and the second constraint transfer vector are superimposed in the complex plane to obtain the actual closed-loop current vector of the first closed-loop path under paired closed-loop conditions. Specifically, this includes: adding the first closed-loop current vector and the second constraint transfer vector to the executed vector in the complex plane to obtain the actual closed-loop current vector of the second closed-loop path under paired closed-loop conditions; adding the actual closed-loop current vector of the first closed-loop path and the actual closed-loop current vector of the second closed-loop path to the executed vector in the complex plane to obtain the total closed-loop current vector. It should be noted that when the vector cancellation effect exists, the magnitude of the total closed-loop current vector is less than the arithmetic sum of the magnitudes of the first and second closed-loop current vectors, reflecting the advantage of paired closed-loop closure in reducing closed-loop impact.

[0074] The maximum cancellation effect strategy can be understood as a selection strategy that prioritizes maximizing the vector cancellation effect between cross-domain paired paths. In practical applications, the larger the absolute values ​​of the first and second cosine values ​​of the cross-domain paired paths, the stronger the reverse pulling effect of the path constraint transmission vector on the loop current vector of the two paths to be closed. Based on this, for each pair of cross-domain paired paths in the set of cross-domain paired paths, the sum of the absolute values ​​of the first and second cosine values ​​of the first and second cosine values ​​is calculated, and the cross-domain paired path with the largest sum of absolute values ​​is selected as the optimal paired path.

[0075] In addition, the cross-domain pairing path can be presented to relevant dispatchers by providing them with information such as the total cross-domain pairing path, the corresponding total loop current vector, and the sum of the absolute values ​​of the first and second included angle cosines. The dispatchers can then select the optimal pairing path based on the actual operation of the power grid and their dispatching experience. Alternatively, the minimum loop current strategy or the strongest offsetting effect strategy can be used for preliminary screening, and the optimal pairing path can be determined by the dispatchers for final confirmation. Based on this, the target loop transfer strategy can be generated.

[0076] After determining the final target loop-closing power transfer strategy through the above methods and steps, it is also possible to determine whether the current amplitude flowing through the common influence node during loop closure meets the line current carrying capacity constraints (rated current carrying capacity of the line through the optimal pairing path, and the maximum continuous current allowed to pass through the line under specified temperature conditions) and equipment capacity constraints (rated current carrying capacity of the switching and protection equipment through the optimal pairing path, and the maximum current that the switching and protection equipment can withstand in a short period of time) based on the magnitude of the total loop-closing current vector. When the magnitude of the total loop-closing current vector simultaneously meets the line current carrying capacity constraints and equipment capacity constraints, a loop-closing control command for the optimal pairing path is generated to ensure that the loop-closing operation will not cause line overload or equipment damage. It should be noted that during the actual execution of the loop-closing control command, the first electrical response quantity (voltage phasor and current phasor) of the common-affected node when the phase angle difference-dominant path is closed, and the second electrical response quantity of the common-affected node when the load difference-dominant path is closed, can also be recorded separately. Based on the phase angle between the first and second electrical response quantities in the complex plane and the third electrical response quantity obtained by vector synthesis, the phase angle deflection direction of the third electrical response quantity in the complex plane can be identified. Based on the phase angle between the first and second electrical response quantities in the complex plane and the phase angle deflection direction, it can be verified whether the vector cancellation effect of the optimal pairing path is triggered.

[0077] This invention provides a method to divide the target distribution network into several topological regions. Based on the connection relationship between each topological region and the main grid power supply nodes, the main-distribution topology coupling relationship is obtained. First and second voltage phasors corresponding to the first and second topological regions to be closed are obtained, respectively. After obtaining the dominant component type of the closing current for each path to be closed between the first and second topological regions based on the first and second voltage phasors, and according to the pairing criteria for different dominant component types of closing current, all paths to be closed are paired to generate a candidate pairing path set. Finally, the constraint transfer relationship matrix of the paths to be closed is determined based on the main-distribution topology coupling relationship. The path constraint transfer relationship matrix is ​​used to analyze the loop current vector cancellation effect of candidate paired paths, and the technical solution of the target loop transfer strategy is obtained. By combining the loop path pairing combination mechanism based on the analysis of the dominant component type of loop path current with the loop path collaborative constraint relationship generation mechanism based on the topological coupling relationship between the distribution network and the main network, the loop current vector cancellation effect in the loop operation can be effectively analyzed, the optimization space of the loop current can be fully explored, and the loop transfer strategy can be optimized. This can improve the effectiveness of the loop transfer strategy generation, effectively reduce the loop current in the loop operation process, and thus ensure the safety and reliability of the loop transfer operation.

[0078] It should be noted that although the steps in the flowchart above are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise explicitly stated in this document, there is no strict order requirement for the execution of these steps, and they can be executed in other orders.

[0079] In one embodiment, such as Figure 3 As shown, a main-distribution coordinated loop transfer supply strategy optimization system is provided, the system comprising: The main distribution coupling relationship analysis module 1 is used to divide the target distribution network into several topological regions and obtain the main distribution topological coupling relationship based on the connection relationship between each topological region and the main power supply node. The loop current type analysis module 2 is used to obtain the dominant component type of the loop current of each path to be closed between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region, respectively. The candidate pairing path acquisition module 3 is used to pair and combine all the paths to be closed based on the criteria that allow pairing of different dominant components of the closed loop current, and generate a set of candidate pairing paths. The target loop closing strategy acquisition module 4 is used to determine the constraint transmission relationship matrix of the path to be closed based on the main-pair topology coupling relationship, and to perform a pairing path loop closing current vector cancellation effect analysis on the candidate pairing path set based on the constraint transmission relationship matrix of the path to be closed, so as to obtain the target loop closing power transfer strategy.

[0080] Specific limitations regarding the master-supplier coordinated loop-based supply strategy optimization system can be found in the limitations of the master-supplier coordinated loop-based supply strategy optimization method described above. The corresponding technical effects are equivalent and will not be repeated here. Each module in the aforementioned master-supplier coordinated loop-based supply strategy optimization system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0081] In summary, the main-distribution coordinated loop-connection power transfer strategy optimization method and system provided by this invention combines a loop-connection path pairing and combination mechanism based on the analysis of the dominant component type of the loop-connection path current with a loop-connection path coordinated constraint relationship generation mechanism based on the topological coupling relationship between the distribution network and the main network. This approach can effectively analyze the loop-connection current vector cancellation effect during the loop-connection operation, fully explore the optimization space of the loop-connection current, and optimize the loop-connection power transfer strategy. It can improve the effectiveness of the loop-connection power transfer strategy generation, effectively reduce the loop-connection current during the loop-connection operation, and thus ensure the safety and reliability of the loop-connection power transfer operation.

[0082] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0083] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A method for optimizing a master-distributor coordinated loop transfer supply strategy, characterized in that, The method includes: The target distribution network is divided into several topological regions, and the main distribution topology coupling relationship is obtained based on the connection relationship between each topological region and the main grid power supply node. Obtain the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region to be closed, respectively, and obtain the dominant component type of the closing current for each path to be closed between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor; Based on the criteria that allow pairing of different dominant components of the loop current, all the proposed loop-closing paths are paired and combined to generate a candidate pairing path set; Based on the main-pair topology coupling relationship, the constraint transfer relationship matrix of the path to be closed is determined, and based on the constraint transfer relationship matrix of the path to be closed, the current vector cancellation effect analysis of the paired path closing is performed on the candidate paired path set to obtain the target closing and transfer strategy.

2. The optimization method for the main-distributor coordinated loop transfer supply strategy as described in claim 1, characterized in that, The step of dividing the target distribution network into several topological regions and obtaining the main distribution topology coupling relationship based on the connection relationship between each topological region and the main grid power supply node includes: Based on the line connection relationship and switch status information of the target distribution network, each main power node is used as the root node, and the electrical connection nodes of the target distribution network are searched and grouped according to the breadth-first search algorithm to obtain multiple distribution networks, and each distribution network is used as a topology region. Obtain the main network connection topology and main network short-circuit capacity of each main network power node, and determine the main network electrical coupling path of each topology region pair based on the main network connection topology and the corresponding topology region connection relationship; Based on the main network electrical coupling path and the corresponding main network short-circuit capacity of each of the aforementioned topology regions, the corresponding coupling path parameters are determined; the coupling path parameters include the total equivalent impedance of the path and the equivalent power supply impedance of the path. The main-distribution topology coupling relationship is generated based on each main network electrical coupling path and the corresponding coupling path parameters.

3. The optimization method for the main-distributor coordinated loop transfer supply strategy as described in claim 1, characterized in that, The step of obtaining the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region to be merged includes: A first voltage phasor dataset and a second voltage phasor dataset corresponding to the first topological region and the second topological region are obtained respectively; both the first voltage phasor dataset and the second voltage phasor dataset include wide-area temporal phase data pairs of several measurement points. Wide-area temporal data with the same sampling time in the first voltage phasor dataset and the second voltage phasor dataset are grouped into a synchronous phasor data group, and the sampling time of the synchronous phasor data group is taken as the target sampling time. Calculate the deviation between the sampling time and the target sampling time for each of the wide-area temporal data pairs that are not included in the synchronization phasor data group. If the deviation is less than a preset synchronization threshold, add the corresponding wide-area temporal data pair to the synchronization phasor data group. The synchronization phasor data group is divided into a first synchronization data group and a second synchronization data group according to its topology region. The voltage phasors of all corresponding measurement points in the first synchronization data group and the second synchronization data group are weighted and averaged to obtain the corresponding first voltage phasor and second voltage phasor.

4. The optimization method for the main-distributor coordinated loop transfer supply strategy as described in claim 1, characterized in that, The step of obtaining the dominant component type of the loop current for each loop-to-be-closed path between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor includes: Based on the first voltage phasor and the second voltage phasor, the phase angle difference of the terminal nodes of each of the paths to be closed is calculated, and the corresponding phase angle difference driving current component is calculated based on each of the terminal node phase angle differences. Obtain the load power difference of each of the end nodes of the path to be closed, and calculate the corresponding load difference drive current component based on the load power difference of each end node. Each of the aforementioned loop paths to be closed is constructed with its equivalent impedance as a reference, and the corresponding phase difference driving current component and load difference driving current component are mapped to the complex plane rectangular coordinate system to obtain the corresponding complex plane information; the complex plane information includes a first complex module, a first complex argument, a second complex module, and a second complex argument; Based on the complex plane information of each of the proposed loop-closing paths, the modulus-length relationship and phase relationship are analyzed to determine the type of dominant component of the corresponding loop-closing current.

5. The optimization method for the main-distributor coordinated loop transfer supply strategy as described in claim 4, characterized in that, The step of analyzing the modulus and phase relationships based on the complex plane information of each of the loop-to-close paths to determine the dominant component type of the corresponding loop current includes: When the ratio of the first complex modulus to the second complex modulus of the loop to be closed is greater than a preset discrimination threshold, the corresponding loop current dominant component type is marked as phase angle difference dominant type. When the ratio of the first complex modulus to the second complex modulus of the loop to be closed is less than the reciprocal of the preset discrimination threshold, the corresponding loop current dominant component type is marked as load difference dominant type. When the ratio of the first complex modulus to the second complex modulus of the loop to be closed is within a preset ratio range, the difference between the first complex argument and the second complex argument is obtained as the corresponding phase angle, and the type of the dominant component of the loop current is determined according to the relationship between the phase angle and the preset phase coordination threshold.

6. The optimization method for the main-distributor coordinated loop transfer supply strategy as described in claim 5, characterized in that, The step of determining the corresponding dominant component type of the closed-loop current based on the relationship between the phase angle and the preset phase coordination threshold includes: Determine whether the phase angle is less than the preset phase coordination threshold. If not, mark the type of the loop current dominant component as mixed dominant type. Otherwise, obtain the vector and argument of the phase angle difference driving current component and the load difference driving current component. Calculate the first and second argument deviations of the vector and argument relative to the first and second complex arguments, respectively; When the first phase angle deviation is less than the second phase angle deviation, the type of dominant component of the closed loop current is marked as the phase angle difference dominant type; When the first phase deviation is greater than the second phase deviation, the type of the dominant component of the closed loop current is marked as the load difference dominant type.

7. The optimization method for the main-distributor coordinated loop transfer supply strategy as described in claim 1, characterized in that, The step of determining the path constraint transfer relationship matrix of the loop to be merged based on the primary and secondary topological coupling relationship includes: Based on the main-partition topology coupling relationship, the common influence nodes of each path pair to be merged are obtained, and the corresponding equivalent circuit model is constructed with the common influence nodes as observation points; the equivalent circuit model includes equivalent voltage sources and equivalent impedance networks; Based on the equivalent circuit model, the influence of one path performing a loop-closing operation on the loop-closing current vector of the other path in each of the paths to be closed is determined, the corresponding path constraint transfer vector is obtained, and the constraint transfer relationship of the paths to be closed is constructed based on the path constraint transfer vector. Generate the constraint transitivity matrix of the paths to be merged based on the constraint transitivity of all the paths to be merged.

8. The optimization method for the main-distributor coordinated loop transfer supply strategy as described in claim 1, characterized in that, The step of performing pairing path loop-closing current vector cancellation effect analysis on the candidate pairing path set based on the constraint transfer relationship matrix of the loop-closing path to be closed, and obtaining the target loop-closing power transfer strategy includes: Based on the constraint transfer relationship matrix of the path to be merged, obtain the constraint transfer vector to be analyzed for each group of candidate paired paths; Based on the first loop current vector, the second loop current vector, and the constraint transfer vector to be analyzed for each group of candidate pairing paths, a corresponding loop current vector triangle is constructed in the complex plane. Each of the closed-loop current vector triangles is subjected to morphological analysis to obtain the corresponding geometric morphological features; the geometric morphological features include the first and second cosine values ​​of the included angle between the constraint transfer vector to be analyzed and the first and second closed-loop current vectors, respectively. When the first and second cosine values ​​of the candidate pairing paths in each group are both negative, it is determined that the corresponding candidate pairing path has a loop current vector cancellation effect, and the candidate pairing path is added to the cross-domain pairing path set. According to the preset pairing path screening strategy, the cross-domain pairing path set is subjected to path screening analysis, and the target loop-closing transfer strategy is generated based on the obtained optimal pairing path; the preset pairing path screening strategy includes at least one of the minimum loop-closing current strategy and the maximum offsetting effect strategy.

9. The optimization method for the main-distributor coordinated loop transfer supply strategy as described in claim 8, characterized in that, When the preset pairing path screening strategy is the minimum loop-closing current strategy, the target loop-closing transfer strategy is generated based on the cross-domain pairing path corresponding to the minimum module length total loop-closing current vector in the cross-domain pairing path set; wherein, the calculation steps of the total loop-closing current vector of each group of cross-domain pairing paths in the cross-domain pairing path set include: Obtain the first loop current vector corresponding to the first loop-closing path and the second loop current vector corresponding to the second loop-closing path in each group of cross-domain pairing paths; Based on the constraint transfer relationship matrix of the path to be merged, obtain the first constraint transfer vector generated by the first merging path on the second merging path when the first merging path performs the merging operation in each group of cross-domain pairing paths, and the second constraint transfer vector generated by the second merging path on the first merging path when the second merging path performs the merging operation. The first loop current vector, the second loop current vector, the first constraint transfer vector, and the second constraint transfer vector corresponding to the cross-domain pairing paths of each group are superimposed in the complex plane to obtain the corresponding total loop current vector.

10. A master-distributor coordinated loop transfer supply strategy optimization system, characterized in that, The system includes: The main-distribution coupling relationship analysis module is used to divide the target distribution network into several topological regions and obtain the main-distribution topological coupling relationship based on the connection relationship between each topological region and the main power supply node. The loop current type analysis module is used to obtain the dominant component type of the loop current for each loop-to-be-closed path between the first topological region and the second topological region based on the first voltage phasor and the second voltage phasor corresponding to the first topological region and the second topological region, respectively. The candidate pairing path acquisition module is used to pair and combine all the paths to be closed based on the criteria that allow pairing of different dominant components of the closing current, and generate a candidate pairing path set. The target loop closing strategy acquisition module is used to determine the constraint transmission relationship matrix of the path to be closed based on the main-pair topology coupling relationship, and to perform a pairing path loop closing current vector cancellation effect analysis on the candidate pairing path set based on the constraint transmission relationship matrix of the path to be closed, so as to obtain the target loop closing and transfer strategy.

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