Power distribution network topology level carrying capacity evaluation method, system, device and storage medium

Abstract

The application provides a power distribution network topology level carrying capacity evaluation method, system, device and storage medium, and belongs to the technical field of power distribution networks. The method comprises the following steps: for each reference scene in a plurality of predetermined reference scenes, when the power distribution network operates under the reference scene, the distributed power supply access capacity of target nodes contained in a target topology unit in the power distribution network is gradually increased, after each capacity increase, the power quality information, line carrying capacity, short-circuit current and upper topology structure carrying capacity of the target nodes are obtained for multi-constraint condition joint evaluation until at least one constraint condition is not satisfied, and then the total distributed power supply access capacity of the target topology unit after the last capacity increase is counted and used as a candidate carrying capacity; and according to a plurality of candidate carrying capacities corresponding to the plurality of reference scenes, the final carrying capacity of the target topology unit is determined. The application can improve the refinement degree and engineering applicability of power distribution network carrying capacity evaluation.

Description

Technical Field

[0001] This application relates to the field of power distribution network technology, and in particular to methods, systems, equipment and storage media for evaluating the topological carrying capacity of power distribution networks. Background Technology

[0002] Currently, regarding the research on the carrying capacity of distributed generation access to distribution networks, some technicians have proposed the concept of comprehensive carrying capacity, which can reflect the comprehensive impact of distributed generation access on the operating conditions of the distribution network. The main evaluation object is the distribution network as a whole. Specifically, it is achieved by obtaining multiple key operating index values ​​of the distribution network when distributed generation is accessed, and using weighted, graded, and scoring methods to analyze and determine the comprehensive carrying capacity evaluation result. However, the comprehensive carrying capacity evaluation result can only reflect the degree of adaptability of the distribution network to distributed generation access, that is, reflect whether the overall carrying capacity level of the distribution network is high, medium or low, which is not conducive to guiding the actual access business at the feeder level, branch level and node level in the distribution network. Summary of the Invention

[0003] The main purpose of this application is to propose a method, system, equipment and storage medium for assessing the topological carrying capacity of distribution networks, aiming to improve the precision and engineering applicability of distribution network carrying capacity assessment.

[0004] To achieve the above objectives, one aspect of this application proposes a method for evaluating the topological carrying capacity of a distribution network, the method comprising: For each of the predetermined multiple benchmark scenarios, when the distribution network is operating under the benchmark scenario, the distributed power access capacity of the target nodes contained in the target topology unit in the distribution network is gradually increased. After each capacity increase, the power quality information, line current carrying capacity, short-circuit current and upper-level topology carrying capacity of the target node are obtained to perform a joint evaluation of multiple constraints until at least one constraint is not satisfied. Then, the total distributed power access capacity of the target topology unit after the last capacity increase is counted and used as a candidate carrying capacity. The final bearing capacity of the target topology unit is determined based on multiple candidate bearing capacities obtained from statistics under the multiple benchmark scenarios.

[0005] Furthermore, each of the aforementioned baseline scenarios is generated by combining at least two of a variety of scenario elements, including load operation status information, distributed power supply output operation characteristics, network topology information, and flexibility adjustment strategy information.

[0006] Furthermore, the power quality information of the target node includes the target node's voltage, harmonic current, harmonic voltage content, and total harmonic distortion (THD); the joint evaluation under multiple constraints includes: The system determines whether the voltage of the target node falls within a preset voltage range, whether the harmonic current of the target node does not exceed the preset national standard limit for harmonic current, whether the harmonic voltage content of the target node does not exceed the preset limit for harmonic voltage content, whether the total harmonic distortion rate of the voltage of the target node does not exceed the preset limit for total harmonic distortion rate, whether the line current carrying capacity of the target node does not exceed the square of the preset apparent power limit of the line, whether the short-circuit current of the target node does not exceed the rated breaking current of the circuit breaker installed at the target node, and whether the carrying capacity of the upper-level topology of the target node does not exceed the preset upper-level carrying capacity boundary value.

[0007] Furthermore, the line carrying capacity of the target node is obtained in the following way: Obtain the active power and reactive power at the beginning of the branch with the target node as the end node; The line current carrying capacity of the target node is obtained by calculating the square of the active power at the beginning of the branch and the square of the reactive power at the beginning of the branch, respectively, and then adding them together.

[0008] Furthermore, the short-circuit current of the target node is obtained in the following way: Before a three-phase metallic short-circuit fault occurs at the target node, the normal operating voltage of the target node is obtained; When a three-phase metallic short-circuit fault occurs at the target node, the equivalent positive sequence impedance of the target node and the current supplied to the target node by each distributed power source connected to the target node are obtained. Calculate the first short-circuit current component of the target node based on its normal operating voltage and equivalent positive sequence impedance. The second short-circuit current component of the target node is calculated based on the current supplied to the target node by each distributed power source connected to the target node. The short-circuit current of the target node is calculated based on the first short-circuit current component and the second short-circuit current component of the target node.

[0009] Further, the carrying capacity of the upper-level topology of the target node includes the carrying capacity of the target branch to which the target node belongs, the carrying capacity of the target feeder to which the target branch belongs, and the carrying capacity of the target main transformer to which the target feeder belongs; the step of determining whether the carrying capacity of the upper-level topology of the target node does not exceed the preset upper-level carrying capacity boundary value includes: It is determined whether the bearing capacity of the target branch does not exceed the preset branch bearing capacity boundary value, whether the bearing capacity of the target feeder does not exceed the preset feeder bearing capacity boundary value, and whether the bearing capacity of the target main transformer does not exceed the preset main transformer bearing capacity boundary value.

[0010] Further, determining the final bearing capacity of the target topological unit based on multiple candidate bearing capacities obtained from corresponding statistics under the multiple benchmark scenarios includes: The minimum candidate bearing capacity is selected from the plurality of candidate bearing capacities, and the minimum candidate bearing capacity is used as the final bearing capacity of the target topology unit.

[0011] To achieve the above objectives, another aspect of this application proposes a distribution network topology-level carrying capacity assessment system, the system comprising: The analysis module is used to, for each of the predetermined multiple benchmark scenarios, when the distribution network is operating under the benchmark scenario, gradually increase the distributed power access capacity of the target nodes contained in the target topology unit in the distribution network. After each capacity increase, the module acquires the power quality information, line current carrying capacity, short-circuit current and upper-level topology carrying capacity of the target node to perform a joint evaluation of multiple constraints until at least one constraint is not satisfied. Then, the module calculates the total distributed power access capacity of the target topology unit after the last capacity increase and uses it as a candidate carrying capacity. The determination module is used to determine the final bearing capacity of the target topology unit based on multiple candidate bearing capacities obtained from corresponding statistics under the multiple benchmark scenarios.

[0012] To achieve the above objectives, another aspect of this application proposes an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method for assessing the carrying capacity of the power distribution network topology.

[0013] To achieve the above objectives, another aspect of this application proposes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for assessing the carrying capacity of the power distribution network topology.

[0014] This application includes at least the following beneficial effects: For each of the predetermined multiple benchmark scenarios, when the distribution network is operating under that benchmark scenario, the distributed power access capacity of the target nodes contained in the target topology unit in the distribution network is gradually increased. After each capacity increase, the power quality information, line current carrying capacity, short-circuit current, and carrying capacity of the upper-level topology of the target node are obtained and a joint evaluation of multiple constraints is performed until at least one constraint is not met. Then, the total distributed power access capacity of the target topology unit after the previous capacity increase is counted and used as a candidate carrying capacity. This allows the evaluation results to reflect the local differences in the distribution network and the transmission relationship of carrying capacity between the upper and lower levels, avoiding the distortion of results caused by evaluating only from a single dimension, either locally or globally. Subsequently, based on the multiple candidate carrying capacities obtained from the corresponding statistics under multiple benchmark scenarios, the final carrying capacity of the target topology unit is determined. This can improve the precision and engineering applicability of the distribution network carrying capacity evaluation, and is beneficial for providing technical support for distribution network planning and construction and distributed power access management. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating a method for evaluating the topological carrying capacity of a distribution network according to an embodiment of this application; Figure 2 This is a schematic diagram of the composition of a distribution network topology-level carrying capacity assessment system provided in an embodiment of this application; Figure 3 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of systems and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0017] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0018] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0020] To address the operational safety risks posed by large-scale distributed power generation integration into the distribution network, it is necessary to develop refined distribution network carrying capacity evaluation standards from a planning perspective. This will ensure the rationality of distributed power generation capacity and location planning from the outset, thereby reducing the regulatory pressure on the distribution network operation. Distributed power sources can include distributed renewable energy sources, such as distributed photovoltaic (PV) equipment.

[0021] Currently, regarding the research on the carrying capacity of distributed generation (DG) access to distribution networks, some technicians have proposed the concept of comprehensive carrying capacity. This concept can reflect the comprehensive impact of DG access on the operating conditions of the distribution network. The main evaluation object is the distribution network as a whole, but it cannot be refined to the carrying capacity analysis of local distribution networks. Specifically, it obtains multiple key operating index values ​​of the distribution network when DG is accessed, such as node voltage, line overload status value, transformer overload status value, network loss, power flow reversal value, voltage fluctuation value, and power supply reliability. These key operating index values ​​are then analyzed using weighted, graded, and scoring methods to determine the comprehensive carrying capacity assessment result. However, this comprehensive carrying capacity assessment result can only reflect the degree of adaptability of the distribution network to DG access, that is, whether the overall carrying capacity level of the distribution network is high, medium, or low. It is not conducive to guiding the actual access business at the feeder level, branch level, and node level of the distribution network.

[0022] Furthermore, in scenarios with a high proportion of distributed generation, the distribution network gradually transforms from the traditional unidirectional power supply mode to a bidirectional or even multidirectional power flow operation mode. The output of distributed generation in the lower-level network, local voltage exceedances, and changes in branch power flow will have a feedback effect on the operating boundary of the upper-level network, while the operational safety constraints of the upper-level grid will also affect the capacity margin that the lower-level grid can accommodate. Traditional unidirectional recursive capacity assessment methods usually conduct assessments according to the logic of first determining the capacity of the upper-level grid and then allocating the capacity of the lower-level grid. This makes it difficult to effectively describe the feedback coupling relationship between the capacity of multiple levels, which may lead to an overall assessment that is too optimistic or a local assessment that is too conservative.

[0023] In view of this, embodiments of this application provide a method, system, device, and storage medium for evaluating the topological carrying capacity of a distribution network. This scheme proposes that for each of several predetermined benchmark scenarios, when the distribution network is operating under that benchmark scenario, the distributed power supply access capacity of the target nodes within the target topological unit in the distribution network is gradually increased. After each capacity increase, the power quality information, line current carrying capacity, short-circuit current, and carrying capacity of the upper-level topology of the target node are acquired and a joint evaluation of multiple constraints is performed until at least one constraint is not met. Then, the total distributed power supply access capacity of the target topological unit after the previous capacity increase is statistically analyzed and used as a candidate carrying capacity. This allows the evaluation results to reflect local differences in the distribution network and the transmission relationship of carrying capacity between upper and lower levels, avoiding the distortion caused by evaluating only from a single local or overall dimension. Subsequently, based on the multiple candidate carrying capacities statistically obtained from multiple benchmark scenarios, the final carrying capacity of the target topological unit is determined. This improves the precision and engineering applicability of the distribution network carrying capacity evaluation, and is beneficial for providing technical support for distribution network planning and construction and distributed power supply access management.

[0024] This application provides a method for assessing the topological carrying capacity of a distribution network, relating to the field of distribution network technology. It can be applied to terminals, servers, or software running on either a terminal or server. In some embodiments, the terminal can be a smartphone, tablet, laptop, desktop computer, etc., but is not limited to these. The server can be configured as an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network. The software can be an application implementing the above method, but is not limited to these forms.

[0025] Please see Figure 1 , Figure 1This is an optional flowchart illustrating a method for evaluating the topological carrying capacity of a distribution network provided in this application embodiment. The method may include, but is not limited to, the following steps S101 to S102: Step S101: For each of the pre-determined multiple benchmark scenarios: When the distribution network is operating under the benchmark scenario, the distributed power access capacity of the target nodes contained in the target topology unit in the distribution network is gradually increased. After each capacity increase, the power quality information, line current carrying capacity, short-circuit current and carrying capacity of the upper-level topology of the target node are obtained to conduct a joint evaluation of multiple constraints until at least one constraint is not satisfied. Then, the total distributed power access capacity of the target topology unit after the last capacity increase is counted and used as a candidate carrying capacity. Step S102: Determine the final bearing capacity of the target topology unit based on the multiple candidate bearing capacities obtained from the corresponding statistics in multiple benchmark scenarios.

[0026] Steps S101 to S102 as shown in the embodiments of this application gradually increase the distributed power supply access capacity of the target node, and in the process, obtain multi-dimensional index values ​​covering the upper-level carrying capacity issues for comprehensive evaluation, thereby improving the refinement and engineering applicability of the distribution network carrying capacity assessment.

[0027] In step S101 of some embodiments, each reference scenario is generated based on a combination of at least two of a variety of scenario elements. The variety of scenario elements includes load operation status information, distributed power generation output operation characteristics, network topology information, and flexibility adjustment strategy information. Among them: the load operation status information includes at least one of summer maximum load condition information, winter maximum load condition information, and spring and autumn minimum load condition information; the distributed power generation output operation characteristics include at least one of the characteristics of photovoltaic output reaching its peak and fluctuating drastically at noon on sunny days, the characteristics of photovoltaic output being zero in cloudy weather, and the characteristics of photovoltaic output being zero at night; the network topology information includes at least one of the normal operation topology information of the distribution network in standard radial power supply, the topology information of power transfer due to fault-induced interconnection switch, and the topology information of dynamic network reconfiguration; the flexibility adjustment strategy information includes at least one of the multi-energy coordinated output strategy information of the integrated energy system, the controlled charging strategy information of electric vehicle charging stations or V2G (Vehicle-to-Grid) discharge strategy information, and the power transfer regulation strategy information of flexible interconnection switches. Multiple benchmark scenarios can be understood as typical days and combinations of different network topologies that reflect the evolution characteristics of source loads within the planning period.

[0028] In step S101 of some embodiments, considering that the above-mentioned distribution network topology-level carrying capacity assessment method is mainly aimed at medium and low voltage distribution networks, for medium voltage distribution networks, the target topology unit may include multiple feeder groups, single feeders, feeder sections, branch lines, and each feeder node; for low voltage distribution networks, the target topology unit may include different phase lines, branch lines at all levels, and user nodes. According to the division relationship of topology units, the node is the smallest object of carrying capacity assessment.

[0029] In step S101 of some embodiments, the content regarding gradually increasing the distributed power access capacity of the target node can be understood as follows: adding the current distributed power access capacity of the target node to a preset capacity increment to obtain the latest distributed power access capacity of the target node, and then adjusting the distributed power access status of the target node accordingly; or, first multiplying the current distributed power access capacity of the target node to a preset capacity growth ratio to obtain the latest capacity increment of the target node, then adding the current distributed power access capacity of the target node to the latest capacity increment to obtain the latest distributed power access capacity of the target node, and then adjusting the distributed power access status of the target node accordingly.

[0030] In step S101 of some embodiments, the power quality information of the target node includes the target node's voltage, harmonic current, harmonic voltage content, and total harmonic distortion rate. The joint evaluation of the target node's power quality information, line current carrying capacity, short-circuit current, and the carrying capacity of the upstream topology under multiple constraints may include the following: Determine whether the voltage of the target node falls within the preset voltage range; if yes, assess whether the node voltage constraint condition is met; if no, assess whether the node voltage constraint condition is not met, in which case the target node has overvoltage or undervoltage. Determine whether the line current carrying capacity of the target node does not exceed the square of the preset line apparent power limit; if yes, assess whether the line current carrying capacity constraint is met; if no, assess whether the line current carrying capacity constraint is not met, and the target node may have branch overload. The system determines whether the harmonic current of the target node does not exceed the preset national standard limit for harmonic current, whether the harmonic voltage content of the target node does not exceed the preset limit for harmonic voltage content, and whether the total harmonic distortion rate of the voltage of the target node does not exceed the preset limit for total harmonic distortion rate. If all three harmonic indicators do not exceed the corresponding limits, the system is deemed to meet the harmonic constraint conditions. If at least one of the three harmonic indicators exceeds the corresponding limit, the system is deemed to not meet the harmonic constraint conditions. Determine whether the short-circuit current at the target node does not exceed the rated breaking current of the circuit breaker installed at the target node; if yes, assess whether the node short-circuit current constraint condition is met; if no, assess whether the node short-circuit current constraint condition is not met; in some cases, the circuit breaker can be replaced with other protective switches. Determine whether the carrying capacity of the target node's parent topology does not exceed the preset parent carrying capacity boundary value. The carrying capacity of the target node's parent topology can be understood as the sum of the capacities of all currently connected distributed power sources in the parent topology of the target node. If yes, the parent carrying capacity constraint is satisfied; if no, the parent carrying capacity constraint is not satisfied.

[0031] Understandably, if all the above key indicator values ​​meet the corresponding constraints after the capacity increase, it means that the current distributed power access capacity of the target node is still within the feasible region, and the next capacity increase operation is allowed. If at least one of the above key indicator values ​​does not meet the corresponding constraints after the capacity increase, it means that the current distributed power access capacity of the target node has reached or exceeded the carrying limit, and the next capacity increase operation is not allowed.

[0032] By introducing the voltage, harmonic current, harmonic voltage content, total harmonic distortion rate, line current carrying capacity and short-circuit current of the node at this level, as well as the carrying capacity of the upper-level topology to which the node belongs, a multi-dimensional constraint assessment is conducted. This allows the assessment results to reflect the local differences in the distribution network and the transmission relationship of carrying capacity between the upper and lower levels, avoiding the distortion of results caused by assessing only from a single local or overall dimension.

[0033] Furthermore, the methods for determining the voltage and line current carrying capacity of the target node can include the following: Obtain the active power, reactive power, resistance, and reactance at the beginning of the branch with the target node as the end node, as well as the voltage at the beginning node of the branch; under normal circumstances, the branch does not contain other nodes. Based on the DistFlow equation of the distribution network branch, the active power, reactive power, resistance, reactance, and voltage of the starting node of the branch are comprehensively calculated to obtain the voltage of the target node. The corresponding calculation formula is as follows: ; In the formula, Let the voltage of the target node j be . Let be the voltage at the first node i of branch ij. Let be the resistance of branch ij. For the reactance of branch ij, Let be the active power at the beginning of branch ij. Let be the reactive power at the beginning of branch ij; After calculating the square of the active power at the beginning of the branch and the square of the reactive power at the beginning of the branch respectively, the two square values ​​are added together to obtain the line current carrying capacity of the target node.

[0034] It should be noted that when there are multiple branches with the target node as the end node, multiple voltages and multiple line current carrying capacities of the target node can be calculated accordingly. Then, the maximum value is selected from the multiple voltages of the target node and used as the final required voltage of the target node, and the maximum value is selected from the multiple line current carrying capacities of the target node and used as the final required line current carrying capacities of the target node.

[0035] Furthermore, the distributed power supply connected to the target node is used as a constant current source for the h-th harmonic. The harmonic current of the target node can be understood as the h-th harmonic current injected into the target node by the constant current source. The preset harmonic current national standard limit is understood as the national standard limit for the h-th harmonic current that the target node is allowed to inject.

[0036] Furthermore, the harmonic voltage content of the target node can be understood as the h-th harmonic voltage content of the target node, the preset harmonic voltage content limit can be understood as the h-th harmonic voltage content limit of the target node at a preset voltage level, and the preset total harmonic distortion rate (THD) limit can be understood as the THD limit of the target node at that preset voltage level. The methods for determining the harmonic voltage content and THD of the target node can include the following: Obtain the h-th harmonic current of each node in the target topology unit, and calculate the h-th harmonic voltage of the target node using a pre-determined node impedance matrix. The corresponding calculation formula is as follows: ; In the formula, Let h be the h-th harmonic voltage of the target node j. This represents the total number of nodes contained in the target topology unit. The impedance value of the target node j, contained in the node impedance matrix, under the influence of the h-th harmonic of node k can be understood as the h-th harmonic voltage response generated at the target node j only when a preset amplitude h-th harmonic current is injected at node k (preferably 1A). At this time, no h-th harmonic current is injected at other nodes in the target topology unit besides node k. When k = j, This is the self-impedance value; when k ≠ j, The mutual impedance value, Let h be the h-th harmonic current at node k; Obtain the effective value of the fundamental voltage of the target node, and then combine it with the h-th harmonic voltage of the target node to calculate the h-th harmonic voltage content and the total harmonic distortion rate of the voltage. The corresponding calculation formulas are as follows: , ; In the formula, The h-th harmonic voltage content of target node j. Let be the total harmonic distortion (THD) of the voltage at target node j. Let be the effective value of the fundamental voltage at target node j. It represents the highest harmonic order and is typically taken as 50.

[0037] Furthermore, the methods for determining the short-circuit current of the target node can include the following: Before a three-phase metallic short-circuit fault occurs at the target node, obtain the normal operating voltage of the target node; Set a three-phase metallic short-circuit fault to occur at the target node, and then obtain the equivalent positive sequence impedance of the target node and the current supplied to the target node by each distributed power source connected to the target node when the fault occurs. Based on the normal operating voltage and equivalent positive sequence impedance of the target node, the first short-circuit current component of the target node is calculated, and the corresponding calculation formula is as follows: ; In the formula, Let be the first short-circuit current component of target node j, which can be understood as the system-side short-circuit current after a fault occurs at target node j. Let be the normal operating voltage of target node j. The equivalent positive sequence impedance of the target node j can be understood as the equivalent positive sequence impedance of the target node j as seen from the system side. Based on the current supplied to the target node by each distributed power source connected to the target node, the second short-circuit current component of the target node is calculated. The corresponding calculation formula is as follows: ; In the formula, The second short-circuit current component of target node j can be understood as the short-circuit current contributed by all distributed power sources connected to target node j after a fault occurs. The set of distributed power sources connected to the target node j. The current supplied to target node j by the m-th distributed power source can be understood as the current component of the m-th distributed power source connected to target node j after being distributed by the network impedance. It should be noted that when the m-th distributed power source connected to target node j is not an inverter-type distributed power source, the current of the m-th distributed power source connected to target node j is the rated current of the m-th distributed power source connected to target node j. When the m-th distributed power source connected to target node j is an inverter-type distributed power source, due to the overcurrent capability limitation of the power electronic devices, the current of the m-th distributed power source connected to target node j is actually the product of the rated current of the m-th distributed power source connected to target node j and the preset inverter short-circuit current limiting coefficient. The preset inverter short-circuit current limiting coefficient is preferably 1.2. Based on the first and second short-circuit current components of the target node, the short-circuit current of the target node is calculated. The corresponding calculation formula is as follows: ; In the formula, Let be the short-circuit current at target node j.

[0038] Furthermore, the carrying capacity of the target node's superior topology includes the carrying capacity of the target branch to which the target node belongs, the carrying capacity of the target feeder to which the target branch belongs, and the carrying capacity of the target main transformer to which the target feeder belongs. The determination of whether the carrying capacity of the target node's superior topology does not exceed a preset superior carrying capacity boundary value can include: determining whether the carrying capacity of the target branch does not exceed a preset branch carrying capacity boundary value, determining whether the carrying capacity of the target feeder does not exceed a preset feeder carrying capacity boundary value, and determining whether the carrying capacity of the target main transformer does not exceed a preset main transformer carrying capacity boundary value. In some embodiments, the target main transformer to which the target feeder belongs can be replaced with a target bus or a target power supply area. Accordingly, the determination can be adjusted to whether the carrying capacity of the target bus does not exceed a preset bus carrying capacity boundary value, or whether the carrying capacity of the target power supply area does not exceed a preset power supply area carrying capacity boundary value. By establishing a progressively detailed carrying capacity assessment mechanism at the node level, branch level, and feeder level, consistency between the assessment results at each level and the superior level can be ensured.

[0039] In step S102 of some embodiments, the process of determining the final bearing capacity of the target topology unit based on multiple candidate bearing capacities obtained from corresponding statistics under multiple benchmark scenarios may include the following: The minimum candidate load capacity is selected from multiple candidate load capacities obtained from statistics under multiple benchmark scenarios. The benchmark scenario corresponding to the minimum candidate load capacity is generally the most unfavorable scenario, that is, the scenario corresponding to the earliest moment when the target topology unit experiences voltage over-limit or equipment overload among multiple benchmark scenarios. It is usually a combination of extremely low load and extremely high photovoltaic output. The minimum candidate load capacity is then directly used as the final load capacity of the target topology unit.

[0040] In some embodiments, there may be multiple target nodes. When the distribution network is operating under various benchmark scenarios, the distributed power access capacity of each target node can be gradually increased simultaneously. After each capacity increase, the power quality information, line current carrying capacity, short-circuit current, and carrying capacity of the upper-level topology of each target node are obtained for joint evaluation of multiple constraints until the evaluation finds that at least one constraint is not met at at least one target node. Then, the total distributed power access capacity of the target topology unit after the last capacity increase is counted and used as a candidate carrying capacity. The total distributed power access capacity of the target topology unit can be understood as the sum of the capacities of all distributed power sources connected to all nodes in the target topology unit. Subsequently, the final carrying capacity of the target topology unit is determined based on the multiple candidate carrying capacities obtained from the corresponding statistics under multiple benchmark scenarios.

[0041] The distribution network topology-level carrying capacity assessment method provided in this application, based on typical source-load scenarios, network topology, operational constraints, and flexible adjustment resource control boundaries, uses feeders, branches, and nodes as comprehensive assessment objects to establish a multi-level topology unit carrying capacity analysis framework. This facilitates the identification of local weak links and key constraint locations, improves the precision and engineering applicability of carrying capacity assessment, and provides more direct and accurate technical support for distribution network planning and construction, distributed resource access management, operation control optimization, and flexible resource collaborative adjustment.

[0042] Please see Figure 2 , Figure 2 This is a schematic diagram of an optional component of a distribution network topology-level carrying capacity assessment system provided in this application embodiment. The system can implement the aforementioned distribution network topology-level carrying capacity assessment method and may include, but is not limited to, the following: The analysis module 201 is used for each of the pre-determined multiple benchmark scenarios: when the distribution network is operating under the benchmark scenario, it gradually increases the distributed power access capacity of the target nodes contained in the target topology unit in the distribution network. After each capacity increase, it obtains the power quality information, line current carrying capacity, short-circuit current and the carrying capacity of the upper-level topology of the target node to perform a joint evaluation of multiple constraints until at least one constraint is not satisfied. Then, it calculates the total distributed power access capacity of the target topology unit after the last capacity increase and uses it as a candidate carrying capacity. The determination module 202 is used to determine the final bearing capacity of the target topology unit based on multiple candidate bearing capacities obtained from corresponding statistics under multiple benchmark scenarios.

[0043] It is understood that the content of the above method embodiments is applicable to this system embodiment. The specific functions implemented in this system embodiment are the same as those implemented in the above method embodiments, and the beneficial effects achieved by this system embodiment are also the same as those achieved by the above method embodiments.

[0044] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method for assessing the carrying capacity of the power distribution network topology. The electronic device may include any smart terminal such as a tablet computer or desktop computer.

[0045] It is understood that the content of the above method embodiments is applicable to the present device embodiments. The specific functions implemented by the present device embodiments are the same as those implemented by the above method embodiments, and the beneficial effects achieved by the present device embodiments are also the same as those achieved by the above method embodiments.

[0046] Please see Figure 3 , Figure 3 This is a schematic diagram illustrating the hardware structure of an electronic device according to another embodiment. The electronic device includes: The processor 301 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application. The memory 302 can be implemented in the form of read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 302 can store the operating system and other applications. When the technical solutions provided in the embodiments of this application are implemented through software or firmware, the relevant program code is stored in the memory 302 and is called and executed by the processor 301. Input / output interface 303 is used to implement information input and output; The communication interface 304 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.). Bus 305 transmits information between various components of the device (e.g., processor 301, memory 302, input / output interface 303, and communication interface 304); The processor 301, memory 302, input / output interface 303 and communication interface 304 are connected to each other within the device via bus 305.

[0047] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for assessing the carrying capacity of a power distribution network topology.

[0048] It is understood that the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented by this storage medium embodiment are the same as those implemented by the above method embodiments, and the beneficial effects achieved by this storage medium embodiment are also the same as those achieved by the above method embodiments.

[0049] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0050] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0051] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0052] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0053] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0054] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0055] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0056] In the embodiments provided in this application, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between systems or units may be electrical, mechanical, or other forms.

[0057] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0058] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0059] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0060] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for evaluating the topological carrying capacity of a distribution network, characterized in that, The method includes: For each of the predetermined multiple benchmark scenarios, when the distribution network is operating under the benchmark scenario, the distributed power access capacity of the target nodes contained in the target topology unit in the distribution network is gradually increased. After each capacity increase, the power quality information, line current carrying capacity, short-circuit current and upper-level topology carrying capacity of the target node are obtained to perform a joint evaluation of multiple constraints until at least one constraint is not satisfied. Then, the total distributed power access capacity of the target topology unit after the last capacity increase is counted and used as a candidate carrying capacity. The final bearing capacity of the target topology unit is determined based on multiple candidate bearing capacities obtained from statistics under the multiple benchmark scenarios.

2. The method for evaluating the topological carrying capacity of a distribution network according to claim 1, characterized in that, Each of the aforementioned baseline scenarios is generated by combining at least two of a variety of scenario elements, including load operation status information, distributed power generation output operation characteristics, network topology information, and flexibility adjustment strategy information.

3. The method for evaluating the topological carrying capacity of a distribution network according to claim 1, characterized in that, The power quality information of the target node includes the voltage, harmonic current, harmonic voltage content, and total harmonic distortion of the target node. The joint evaluation under multiple constraints includes: The system determines whether the voltage of the target node falls within a preset voltage range, whether the harmonic current of the target node does not exceed the preset national standard limit for harmonic current, whether the harmonic voltage content of the target node does not exceed the preset limit for harmonic voltage content, whether the total harmonic distortion rate of the voltage of the target node does not exceed the preset limit for total harmonic distortion rate, whether the line current carrying capacity of the target node does not exceed the square of the preset apparent power limit of the line, whether the short-circuit current of the target node does not exceed the rated breaking current of the circuit breaker installed at the target node, and whether the carrying capacity of the upper-level topology of the target node does not exceed the preset upper-level carrying capacity boundary value.

4. The method for evaluating the topological carrying capacity of a distribution network according to claim 1, characterized in that, The line carrying capacity of the target node is obtained in the following way: Obtain the active power and reactive power at the beginning of the branch with the target node as the end node; The line current carrying capacity of the target node is obtained by calculating the square of the active power at the beginning of the branch and the square of the reactive power at the beginning of the branch, respectively, and then adding them together.

5. The method for evaluating the topological carrying capacity of a distribution network according to claim 1, characterized in that, The short-circuit current of the target node is obtained in the following way: Before a three-phase metallic short-circuit fault occurs at the target node, the normal operating voltage of the target node is obtained; When a three-phase metallic short-circuit fault occurs at the target node, the equivalent positive sequence impedance of the target node and the current supplied to the target node by each distributed power source connected to the target node are obtained. Calculate the first short-circuit current component of the target node based on its normal operating voltage and equivalent positive sequence impedance. The second short-circuit current component of the target node is calculated based on the current supplied to the target node by each distributed power source connected to the target node. The short-circuit current of the target node is calculated based on the first short-circuit current component and the second short-circuit current component of the target node.

6. The method for evaluating the topological carrying capacity of a distribution network according to claim 3, characterized in that, The carrying capacity of the upper-level topology of the target node includes the carrying capacity of the target branch to which the target node belongs, the carrying capacity of the target feeder to which the target branch belongs, and the carrying capacity of the target main transformer to which the target feeder belongs. The step of determining whether the bearing capacity of the upper-level topology of the target node does not exceed the preset upper-level bearing capacity boundary value includes: It is determined whether the bearing capacity of the target branch does not exceed the preset branch bearing capacity boundary value, whether the bearing capacity of the target feeder does not exceed the preset feeder bearing capacity boundary value, and whether the bearing capacity of the target main transformer does not exceed the preset main transformer bearing capacity boundary value.

7. The method for evaluating the topological carrying capacity of a distribution network according to claim 1, characterized in that, The step of determining the final bearing capacity of the target topology unit based on multiple candidate bearing capacities obtained from corresponding statistics under the multiple benchmark scenarios includes: The minimum candidate bearing capacity is selected from the plurality of candidate bearing capacities, and the minimum candidate bearing capacity is used as the final bearing capacity of the target topology unit.

8. A distribution network topology-level carrying capacity assessment system, characterized in that, The system includes: The analysis module is used to, for each of the predetermined multiple benchmark scenarios, when the distribution network is operating under the benchmark scenario, gradually increase the distributed power access capacity of the target nodes contained in the target topology unit in the distribution network. After each capacity increase, the module acquires the power quality information, line current carrying capacity, short-circuit current and upper-level topology carrying capacity of the target node to perform a joint evaluation of multiple constraints until at least one constraint is not satisfied. Then, the module calculates the total distributed power access capacity of the target topology unit after the last capacity increase and uses it as a candidate carrying capacity. The determination module is used to determine the final bearing capacity of the target topology unit based on multiple candidate bearing capacities obtained from corresponding statistics under the multiple benchmark scenarios.

9. An electronic device, characterized in that, The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the distribution network topology-level carrying capacity assessment method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the distribution network topology-level carrying capacity assessment method according to any one of claims 1 to 7.

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