A power distribution system disaster reconstruction method considering network reconstruction and island division

Abstract

The application provides a power distribution system disaster reconstruction method considering network reconstruction and island division. The method comprises the following steps: constructing a power distribution system disaster network dynamic reconstruction and island division mathematical model based on a power distribution network topology, determining an objective function and constraint conditions of the model; determining a response condition of the power distribution system in a disaster coming process based on a network reconstruction scheme; configuring a distributed power supply model in the power distribution system; and calculating an optimal network reconstruction scheme by using a mathematical optimization method based on a structure, an objective function and constraint conditions of the network reconstruction and island division mathematical model, the response condition of the power distribution system in the disaster coming process and the distributed power supply model configured in the system, so as to minimize the load shedding and switch operation cost. The method realizes the flexibility improvement of the power distribution system in a disaster stage by resource allocation and network topology reconstruction in the disaster stage, reduces the load shedding and operation cost of the power distribution system in the disaster, and guarantees the supply of important loads.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power distribution system disaster dynamic technology, and particularly relates to a power distribution system disaster reconstruction method considering network reconstruction and island division. BACKGROUND

[0002] In recent years, under the dual driving of global climate change and urbanization, the power distribution system is facing unprecedented challenges. Extreme weather events such as hurricanes, floods and extreme temperature fluctuations pose a serious threat to the stability and continuity of the power distribution system. Therefore, it is crucial to enhance the reliability of the power distribution system to ensure power supply safety. One important way to improve the reliability of the power distribution system is to restore the load after power failure by reconfiguring the network topology and dividing the island.

[0003] The in-incident response stage in the evolution process of extreme events emphasizes the ability of rapid response and emergency disposal, and through the automatic control system and intelligent scheduling strategy, the influence of the fault on the system is reduced. In the process of disaster, through the switching operation of the tie switch, important load can be restored, and at the same time, in order to avoid the further spread of the fault, distributed generation (DG) can rely on the tie line to form an independent power supply island to isolate the fault and supply critical load. However, it is not easy to effectively form an island with multiple DGs in the power distribution system, especially in the case of catastrophic events leading to facility damage. The flexibility of the power distribution network topology provides more possibilities for the optimization of active power distribution network fault recovery strategies. How to develop effective fault recovery strategies for power distribution system topology transformation has become one of the research hotspots in the field of distribution network.

[0004] The power grid elasticity reflects the defense capability, real-time response capability and recovery capability of the system in the face of extreme disaster events. Unlike traditional reliability and security evaluation methods, the elastic power distribution network pays more attention to the response to "N-k" multiple fault scenarios. When the power distribution network is damaged on a large scale and cannot meet the demand of all loads, by adjusting the network topology, optimizing the unit output and reducing part of the load, the overall benefit of the system is maximized under the premise of ensuring safe operation.

[0005] At present, the existing technology mainly focuses on the pre-disaster and post-disaster stages in improving the elasticity of the power distribution network, relying on pre-disaster equipment reinforcement measures and post-disaster emergency resource allocation. There is no effective method in the existing technology for how to dynamically reconstruct the power distribution system in the disaster. SUMMARY

[0006] The present application provides a power distribution system disaster reconstruction method considering network reconstruction and island division, to realize effective disaster reconstruction and recovery of the power distribution system.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions.

[0008] A method for power distribution system disaster reconstruction considering network reconstruction and islanding, comprising:

[0009] Based on the distribution network topology, a mathematical model for dynamic network reconstruction and islanding during a power distribution system disaster is constructed, and the objective function and constraints of the mathematical model are determined;

[0010] Determine the response of the power distribution system to a disaster based on the network reconstruction plan;

[0011] configuring a distributed power supply model in the power distribution system;

[0012] Based on the structure, objective function and constraints of the mathematical model of network reconstruction and island partitioning, as well as the response of the distribution system during disasters and the distributed power supply model configured in the system, the optimal network reconstruction plan is calculated using a mathematical optimization method to minimize the load shedding and switching operation costs.

[0013] Preferably, the method of constructing a mathematical model for dynamic network reconstruction and islanding during a power distribution system disaster based on the power distribution network topology and determining the objective function and constraints of the mathematical model for dynamic network reconstruction and islanding include:

[0014] Based on the distribution network topology, a mathematical model for dynamic network reconstruction and islanding during a power distribution system disaster is constructed. The objective function of the mathematical model is set as a multi-objective function that takes into account the importance of the load and the cost of switch operation:

[0015]

[0016] Where T is the number of time periods in the entire reconstruction cycle of the distribution network, c load is the load shedding factor, Indicates the load shedding ratio, is the load of each node, N bus represents the number of nodes in the distribution network, c switch represents the switching operation cost coefficient, is the disconnection state of line i at time t, the switch is disconnected for 0, the switch is connected for 1, N line Indicates the number of switches in the distribution network;

[0017] The constraints of the mathematical model for dynamic reconstruction and islanding in distribution network disasters include power flow constraints, load shedding constraints, safe operation constraints, radial topology constraints, and distributed power supply operation constraints.

[0018] The power flow constraint is:

[0019]

[0020] During the disaster, the capacity, voltage and current of the fault line must satisfy the following constraints:

[0021]

[0022] where p j and q j represent the active and reactive power injected by node j at time t, respectively; P and Q represent the power flow of branch; δ j represents the set of all incoming branches of node j; γ j represents the set of all outgoing branches of node j; l ij represents the square of the branch ij current amplitude; r, x, g and b represent the resistance, reactance, ground parallel conductance and susceptance, respectively; v j represents the square of the voltage amplitude at node j; m ij is an auxiliary variable, which takes the largest possible value;

[0023] The load shedding constraint is:

[0024]

[0025] The safe operation constraint is:

[0026] I ij,min ≤I ij,t ≤I ij,max

[0027] Z ij,t I ij,min ≤I ij,t ≤Z ij,t I ij,max

[0028] V j,min ≤V j,t ≤V j,max

[0029] The radial topology constraint is:

[0030]

[0031] wherein, represents whether the partition region with node q as the leading node exists at time t, N C represents the number of power sources that can form an island, represents whether node i belongs to partition region q at time t; is the output power of the leading node of partition region q at time t, P k,L is the virtual load of node k, represents the virtual power of line ij in the partition area q;

[0032] The distributed power supply operation constraints are:

[0033]

[0034] in, Respectively represent the lower limit and upper limit of the active power output of the distributed generation, They represent the lower and upper limits of the reactive power output of distributed generation, and is the active and reactive power output of distributed generation i at time t, N DG Represents the set of all nodes configured with distributed power sources.

[0035] Preferably, the network reconstruction scheme is based on determining the response of the power distribution system during a disaster, including:

[0036] Based on the structure of the network reconstruction and island partitioning mathematical model, the distribution network reconstruction and optimization are carried out during the disaster process, the connecting lines in the distribution network are adjusted, and the distributed power output characteristics are used to connect with the load to form a temporary distribution network island, and the load is restored.

[0037] Preferably, configuring the distributed power supply model in the power distribution system includes:

[0038] The distributed power supply model configured in the power distribution system is as follows:

[0039]

[0040] in, Respectively represent the lower limit and upper limit of the active power output of the distributed generation, and They represent the lower and upper limits of the reactive power output of distributed generation, and is the active and reactive power output of distributed generation i at time t, N DG Represents the set of all nodes configured with distributed power sources.

[0041] Preferably, the method of calculating the optimal network reconstruction solution by using a mathematical optimization method to minimize load shedding and switching operation costs based on the structure, objective function and constraints of the network reconstruction and islanding mathematical model, the response of the distribution system during a disaster, and the distributed power supply model configured in the system, includes:

[0042] Based on the structure, objective function and constraints of the above-mentioned mathematical model of network reconstruction and islanding, as well as the response of the distribution system during a disaster and the distributed power supply model configured in the system, the optimal network reconstruction plan is calculated using a mathematical optimization method to minimize the load shedding and switch operation costs. The switch state is dynamically adjusted during the disaster to balance the load shedding cost and power supply restoration capability. The optimal network reconstruction plan includes: determination of the islanding area; optimization of the switch operation timing; load recovery strategy to ensure optimal load distribution; and line flow analysis to prevent overload or voltage exceeding the limit.

[0043] It can be seen from the technical solutions provided by the above-mentioned embodiments of the present invention that this method verifies the effectiveness of the model by testing the improved PG&E 69-node distribution system. This method improves the resilience of the distribution system during a disaster by allocating resources and reconstructing the network topology during the disaster phase of the distribution system, significantly reduces the load shedding and operating costs of the distribution system during a disaster, and ensures the supply of important loads.

[0044] Additional aspects and advantages of the present invention will be set forth in part in the following description, will become apparent from the following description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 The present invention provides a flowchart of a method for dynamic reconstruction of a power distribution system during a disaster, taking into account network reconstruction and island division.

[0047] Figure 2 A network topology diagram of an IEEE 33-node power distribution network system is provided in an embodiment of the present invention.

[0048] Figure 3 A network topology diagram of a PG&E 69-node distribution network system provided in an embodiment of the present invention.

[0049] Figure 4 A diagram of the dynamic topology reconstruction process of a PG&E 69-node distribution network system during a disaster is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0051] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the description of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, "connected" or "coupled" as used herein may include wireless connections or couplings. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items.

[0052] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention pertains. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such herein, will not be interpreted in an idealized or overly formal sense.

[0053] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each embodiment does not constitute a limitation on the embodiments of the present invention.

[0054] The flowchart of a method for dynamic reconstruction of a power distribution system during a disaster considering network reconstruction and island division provided by an embodiment of the present invention is as follows: Figure 1 As shown, the following processing steps are included:

[0055] Step S1: Based on the distribution network topology, a mathematical model for dynamic network reconstruction and island partitioning during a distribution system disaster is constructed.

[0056] The objective function of the mathematical model of network dynamic reconstruction and island partitioning is set to a multi-objective function that takes into account the importance of load and switch operation cost:

[0057]

[0058]

[0059] Where T is the number of time periods in the entire reconstruction cycle of the distribution network, c load is the load shedding factor, Indicates the load shedding ratio, is the load of each node, N bus represents the number of nodes in the distribution network, c switch represents the switching operation cost coefficient, is the disconnection state of line i at time t, the switch is disconnected for 0, the switch is connected for 1, N line Indicates the number of switches in the power distribution network.

[0060] The constraints of the mathematical model for dynamic reconstruction and island partitioning in distribution network disasters include flow constraints, load shedding constraints, safe operation constraints, radial topology constraints and distributed power supply operation constraints.

[0061] The power flow constraint is:

[0062]

[0063] During a disaster, the capacity, voltage, and current of the fault line must meet the following constraints:

[0064]

[0065] In the formula, during the period t, p j and q j denote the active and reactive power injected into node j respectively; P and Q denote the power flow of the branch; δ j represents the set of all branches flowing into node j; γ j represents the set of all branches out of node j; l ij represents the square of the current amplitude of branch ij; r, x, g, and b represent resistance, reactance, grounded shunt conductance, and susceptance, respectively; v j represents the square of the voltage amplitude at node j; m ij It is an auxiliary variable and takes the largest possible value.

[0066] The load shedding constraint is:

[0067]

[0068] The safe operation constraints are:

[0069] I ij,min ≤I ij,t ≤I ij,max

[0070] Z ij,t I ij,min ≤I ij,t ≤Z ij,t Iij,max

[0071] V j,min ≤V j,t ≤V j,max

[0072] The radial topology constraints are:

[0073]

[0074] in, Indicates whether the segmentation area with node q as the dominant node exists at time t, N C Indicates the number of power sources that can form an island, including the main grid. Indicates whether node i belongs to the partition region q at time t; is the output power of the master node in partition area q at time t, P k,L is the virtual load of node k, represents the virtual power of line ij within partition q. During island self-balancing control, the above equation introduces a single commodity flow constraint from the perspective of virtual power flow to ensure graph connectivity. This prevents the formation of isolated islands with only one distributed generation source. Furthermore, it enables the parallel optimization of network radiation and interconnection constraints.

[0075] The distributed power supply operation constraints are:

[0076]

[0077] in, Respectively represent the lower limit and upper limit of the active power output of the distributed generation, They represent the lower and upper limits of the reactive power output of distributed generation, and is the active and reactive power output of distributed generation i at time t, N DG Represents the set of all nodes configured with distributed power sources.

[0078] Through step S1, a complete mathematical model of network reconstruction and island partitioning is established, and the objective function and specific constraints are clarified. In the subsequent step S2, based on the network topology reconstruction optimization plan, the dynamic response of the distribution system during the disaster process is calculated. At the same time, in step S4, the final network reconstruction plan is used to ensure that load shedding is minimized and the switching operation cost is reduced.

[0079] Step S2: Based on the network reconstruction plan, determine the response of the distribution system during the disaster.

[0080] In this step, based on the structure of the above-mentioned mathematical model of network reconstruction and island division, the distribution network is reconstructed and optimized during the disaster, and the interconnection lines in the distribution network are actively adjusted. At the same time, the output characteristics of distributed power sources are utilized to connect with the loads to form temporary distribution network islands, thereby restoring more loads.

[0081] Step S3: Select and configure distributed power sources in the system so that the load power supply demand can still be met after island division.

[0082] In this step, the distributed power supply model configured in the system is as follows:

[0083]

[0084] in, Respectively represent the lower limit and upper limit of the active power output of the distributed generation, and They represent the lower and upper limits of the reactive power output of distributed generation, and is the active and reactive power output of distributed generation i at time t, N DG Represents the set of all nodes configured with distributed power sources.

[0085] The distributed power supply configured in the system can expand the power supply coverage of the distributed power supply beyond the adjacent nodes through the tie switch in the distribution network to restore more critical loads, that is, to form an island.

[0086] Step S4: Determine a network reconstruction plan with the goal of minimizing load shedding and switching operation costs.

[0087] While ensuring the supply of critical loads, balance the load shedding costs and switch operation costs of the distribution network to achieve a balance between load supply and costs. Determine the network reconstruction plan with the goal of minimizing load shedding and switch operation costs.

[0088] Take the IEEE33 node system as an example for simple verification. Figure 2 As shown, the tie switches in the system are at 8-21, 9-15, 12-22, 18-33, and 25-29, and distributed power sources are configured at nodes 11, 16, and 20 in the IEEE33-node system, respectively.

[0089] Based on the structure, objective function, and constraints of the mathematical model for network reconstruction and islanding, and with the goal of minimizing load shedding and switch operation costs, the fault locations are set as shown in Table 1 below. The optimal network reconstruction solution is calculated, and the switch status is dynamically adjusted during the disaster to balance the load shedding cost and power restoration capability.

[0090] The final dynamic reconstruction solution is shown in Table 2. The final dynamic reconstruction solution includes: determination of islanding areas; optimization of switch operation timing; load restoration strategy to ensure optimal load distribution; and line flow analysis to prevent overload or voltage exceeding the limit.

[0091] Table 1 Statistics of fault lines in each period

[0092]

[0093] Table 2 Final dynamic reconstruction scheme

[0094]

[0095] During a disaster, the system first calculates the optimal topology reconstruction plan based on the fault location and load demand, ensuring minimal load shedding. The objective function also considers: the priority of critical loads to ensure their supply; the rationality of islanding to maintain island power supply stability; and the cost of switching operations to minimize the impact of frequent switching on equipment.

[0096] The following is our second example, which uses the PG&E69 node distribution network system to test and verify the effectiveness and accuracy of the proposed method. Figure 3 A network topology diagram of a PG&E 69-node distribution network system provided in an embodiment of the present invention.

[0097] The simulations in this example were written using MATLAB R2021a and run on a laptop with a 64-bit operating system, a 2.4GHz quad-core CPU, and 8GB of memory. To address the MISOCP problem, the distribution network reconfiguration model was implemented using YALMIP and solved using the CPLEX commercial solver.

[0098] The system voltage level is 12.66kV, the reference power is 10MVA, and the total active and reactive power of the load are 2372kW and 1681kvar, respectively. Assume that all lines in the system are equipped with section switches, which are normally closed, represented by solid lines; the tie switches are initially open, represented by dashed lines, such as "11-43," "13-21," "15-46," "27-65," and "50-59." Figure 3 As shown in Figure 1, node 1 is the main power feeder. Nodes 5, 19, 33, 44, 47, and 63 are connected to DGs with capacities of 200kW, 500kW, 500kW, 600kW, 500kW, and 400kW, respectively. The unit power outage loss cost of the system is set to 13 yuan / (kW·h).

[0099] To test the effectiveness of post-disaster reconstruction, we used a four-hour period after the disaster as the research period and assumed that the distribution network was reconfigured every hour. Table 3 shows the statistics of faulty lines in the system.

[0100] Table 3 Statistics of fault lines in each period

[0101]

[0102] Figure 4 A diagram of a PG&E 69-node distribution network system topology dynamic reconstruction process during a disaster is provided in an embodiment of the present invention, such as Figure 4 During the reconstruction of the distribution network during a disaster, the system deployed distributed power sources at multiple nodes.

[0103] like Figure 4 As shown in (a), when the complex disaster begins, the system has less power outages and the power supply to the power-lost area can be restored by simply closing the contact switch 27-65. Figure 4 As shown in (b), considering the cost of switch operation, the system chooses node 44 as the main node to form an island. When the disaster is further aggravated, for example Figure 4 When the degree of power outage in the system increases in (c), the system will actively cut off some loads, close the tie switches 50-59, and form an island at the same time to ensure the power supply of important loads and avoid the formation of a ring network. When the disaster worsens, such as Figure 4 As shown in (d), the system interconnection switch 11-43 is actuated, and the node 44 is expanded as the island of the master node to restore power supply to the power-off area.

[0104] In order to analyze the feasibility and optimality of the load recovery strategy proposed in this invention compared with existing methods, we used three different methods to set up the fault scenario.

[0105] Scenario 1: Using the recovery model proposed in this invention.

[0106] Scenario 2: No reconstruction is performed during the disaster, and the topology is reconstructed only after the disaster ends (assuming it is t0+3 time periods later).

[0107] Scenario 3: No topology reconstruction is performed during or after the disaster.

[0108] The comparison results are shown in Table 4. It can be seen that when the dynamic reconstruction strategy is adopted, the cost of Scenario 1 is 71.11% lower than that of Scenario 2 and 81.15% lower than that of Scenario 3. This shows that for the PG&E 69-node system, the dynamic reconstruction scheme proposed in this method significantly improves the resilience of the distribution system, while significantly reducing costs and enhancing load power supply capacity.

[0109] Table 4 Comparison of results under different fault scenarios

[0110]

[0111] The PG&E 69-bus system contains more lines than typical distribution networks. The proposed dynamic reconfiguration method can quickly and efficiently adjust the system topology as faults evolve, achieving coordinated load recovery and preventing the formation of system islands. Therefore, the proposed strategy can significantly improve the resilience of large-scale distribution networks.

[0112] Based on the above analysis, the dynamic reconstruction scheme proposed in this method can flexibly respond to long-term and highly complex fault problems in the distribution network during the evolution of disasters. Simulation studies on the PG&E 69-node system show that this scheme can not only quickly adjust the system topology, form island power supply, and coordinate the restoration of critical loads, but also effectively reduce the number of segmented switch operations, significantly improving the resilience of the distribution network and load power supply capacity under complex disaster conditions. Compared with traditional static reconstruction methods or strategies that do not perform reconstruction at all, this method shows superior economy and adaptability, providing a new idea for feasibility and efficiency of large-scale distribution network disaster recovery.

[0113] In summary, the present invention has the following advantages compared to the prior art:

[0114] Currently, research on improving distribution network resilience, both domestically and internationally, focuses primarily on the pre-disaster and post-disaster phases, relying on pre-disaster equipment reinforcement measures and post-disaster emergency resource deployment. However, research on dynamic adjustments during disasters remains relatively weak.

[0115] This invention overcomes the limitation of traditional virtual power flow constraints, which cannot simultaneously optimize connectivity constraints and radial constraints. It also solves the problem of being unable to determine the number of islands during island division and avoids the limitation that an island contains only one DG by default. Through the improved virtual power flow constraints, this invention can more flexibly support the formation of multiple island regions (assuming a total of q), thereby formulating a more optimized reconstruction strategy.

[0116] Using the YALMIP toolbox in MATLAB for modeling and the CPLEX solver for solving can effectively simplify the modeling process, improve computing efficiency, and provide strong adaptability to meet the timeliness requirements of real-time scheduling.

[0117] Those skilled in the art will appreciate that the accompanying drawings are merely schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0118] Those skilled in the art can clearly understand the present application by the description of the above embodiments. Based on such an understanding, the technical solutions of the present application can be embodied in the form of a software product, and the computer software product can be stored in a storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, and the like, and includes a plurality of instructions to cause a computer device (which can be a personal computer, a server, or a network device, and the like) to execute the methods described in the various embodiments or some parts of the embodiments.

[0119] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each of the embodiments mainly describes the difference from other embodiments. In particular, for the device or system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the related parts can be referred to the part of the method embodiments. The above-described device and system embodiments are merely illustrative, and the units described as separate components can be or can not be physically separated, and the components displayed as units can be or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiments according to the actual needs. Those skilled in the art can understand and implement it without creative labor.

[0120] The above describes only the preferred embodiments of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for power distribution system disaster reconstruction considering network reconstruction and island division, characterized in that: include: Based on the distribution network topology, a mathematical model for dynamic network reconstruction and islanding during a power distribution system disaster is constructed, and the objective function and constraints of the mathematical model are determined; Based on the network reconstruction plan, determining the response of the distribution system during the disaster, including: optimizing the distribution network reconstruction during the disaster based on the structure of the network dynamic reconstruction and islanding mathematical model, adjusting the tie lines in the distribution network, utilizing the output characteristics of distributed power sources and connecting with loads to form temporary distribution network islands, and restoring the loads; configuring a distributed power supply model in the power distribution system; Based on the structure, objective function, and constraints of the mathematical model for dynamic network reconfiguration and islanding, as well as the response of the distribution system to a disaster and the distributed power generation model configured in the system, a mathematical optimization method is used to calculate the optimal network reconfiguration solution in order to minimize load shedding and switching operation costs; The above-mentioned construction of a mathematical model for dynamic network reconstruction and islanding during a power distribution system disaster based on the power distribution network topology and determination of the objective function and constraints of the mathematical model for dynamic network reconstruction and islanding include: Based on the distribution network topology, a mathematical model for dynamic network reconstruction and islanding during a power distribution system disaster is constructed. The objective function of the mathematical model is set as a multi-objective function that takes into account the importance of the load and the cost of switch operation: Where T is the number of time periods in the entire reconstruction cycle of the distribution network, c load is the load shedding factor, Indicates the load shedding ratio, The load of each node, N bus represents the number of nodes in the distribution network, c switch represents the switching operation cost coefficient, is the disconnection state of line i at time t, the switch is disconnected for 0, the switch is connected for 1, N line Indicates the number of switches in the distribution network; The constraints of the mathematical model for dynamic network reconstruction and islanding during a power distribution system disaster include power flow constraints, load shedding constraints, safe operation constraints, radial topology constraints, and distributed power supply operation constraints. The power flow constraint is: During a disaster, the capacity, voltage, and current of the fault line must meet the following constraints: In the formula, during the period t, p j and q j denote the active and reactive power injected into node j respectively; P and Q denote the power flow of the branch; δ j represents the set of all branches flowing into node j; γ j represents the set of all branches out of node j; l ij represents the square of the current amplitude of branch ij; r, x, g, and b represent resistance, reactance, grounded shunt conductance, and susceptance, respectively; v j represents the square of the voltage amplitude at node j; m ij It is an auxiliary variable and takes the largest possible value; The load shedding constraint is: The safe operation constraints are: I ij,min ≤I ij,t ≤I ij,max Z ij,t I ij,min ≤I ij,t ≤Z ij,t I ij,max In j,min ≤V j,t ≤V j,max The radial topology constraints are: in, Indicates whether the segmentation area with node q as the dominant node exists at time t, N C Indicates the number of power sources that can form an island. Indicates whether node i belongs to the partition region q at time t; is the output power of the master node in partition area q at time t, P k,L is the virtual load of node k, represents the virtual power of line ij in the partition area q; The distributed power supply operation constraints are: in, They represent the lower and upper limits of the active power output of the distributed generation, Respectively represent the lower limit and upper limit of the reactive power output of distributed generation, and is the active and reactive power output of distributed generation i at time t, N DG Represents the set of all nodes configured with distributed power sources.

2. The method according to claim 1, characterized in that The configuration of the distributed power supply model in the power distribution system includes: The distributed power supply model is as follows: in, They represent the lower and upper limits of the active power output of the distributed generation, and Respectively represent the lower limit and upper limit of the reactive power output of distributed generation, and is the active and reactive power output of distributed generation i at time t, N DG Represents the set of all nodes configured with distributed power sources.

3. The method according to claim 2, characterized in that The structure, objective function and constraints of the mathematical model of network dynamic reconstruction and islanding, as well as the response of the distribution system during a disaster and the distributed power model configured in the system, are used to calculate the optimal network reconstruction solution by minimizing load shedding and switching operation costs using a mathematical optimization method, including: Based on the structure, objective function and constraints of the mathematical model of network dynamic reconstruction and islanding, as well as the response of the distribution system during a disaster and the distributed power supply model configured in the system, the optimal network reconstruction plan is calculated using a mathematical optimization method to minimize the load shedding and switch operation costs. The switch state is dynamically adjusted during the disaster to balance the load shedding cost and power supply restoration capability. The optimal network reconstruction plan includes: determination of the island area; optimization of the switch operation timing; load recovery strategy to ensure optimal load distribution; and line flow analysis to prevent overload or voltage overruns.

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