Power distribution system in-disaster reconstruction method considering network reconstruction and island division

Abstract

The invention provides a power distribution system in-disaster reconstruction method considering network reconstruction and island division. The method comprises the following steps: constructing a power distribution system in-disaster network dynamic reconstruction and island division mathematical model based on a power distribution network topology, and determining an objective function and constraint conditions of the model; based on the network reconstruction scheme, determining a response condition of the power distribution system in a disaster coming process; configuring a distributed power supply model in the power distribution system; and calculating an optimal network reconstruction scheme by using a mathematical optimization method by minimizing load shedding and switch operation cost based on the structure, the objective function and the constraint condition of the network reconstruction and island division mathematical model, the response condition of the power distribution system in the disaster coming process and a distributed power supply model configured in the system. According to the method, through resource allocation and network topology reconstruction of the in-disaster stage of the power distribution system, elastic improvement of the in-disaster stage of the power distribution system is realized, load shedding and operation costs of the power distribution system in the disaster are reduced, and supply of important loads is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of dynamic technology in power distribution system disasters, and in particular to a method for power distribution system disaster reconstruction taking into account network reconstruction and island division. Background Art

[0002] In recent years, driven by global climate change and urbanization, power distribution systems are facing unprecedented challenges. Extreme weather events such as hurricanes, floods, and extreme temperature fluctuations pose a serious threat to the stability and continuity of power distribution systems. Therefore, enhancing the reliability of power distribution systems is crucial to ensuring power supply security. An important way to improve the reliability of power distribution systems is to restore loads after power outages by reconfiguring network topology and dividing islands.

[0003] During the in-flight response phase of the evolution of extreme events, emphasis is placed on rapid response and emergency handling capabilities, and automated control systems and intelligent scheduling strategies are used to reduce the impact of faults on the system. During a disaster, important loads can be restored through the switching operation of the interconnection switch. At the same time, in order to avoid further propagation of the fault, distributed generation (DG) can rely on interconnection lines to form independent power supply islands to isolate the critical loads of the fault supply. However, it is not easy to effectively island multiple DGs in the distribution system, especially when catastrophic events cause facility damage. The flexibility of the distribution network topology provides broader possibilities for the optimization of active distribution network fault recovery strategies. How to formulate effective fault recovery strategies for distribution system topology changes has become one of the research hotspots in the distribution network field.

[0004] Grid resilience reflects the system's defense, real-time response and recovery capabilities in the face of extreme disaster events. Different from traditional reliability and safety assessment methods, resilient distribution networks focus more on coping with "Nk" multiple fault scenarios. When the distribution network cannot meet all load demands due to large-scale damage, the overall benefits of the system can be maximized while ensuring safe operation by adjusting the network topology, optimizing unit output and reducing some loads.

[0005] At present, existing technologies for improving the resilience of distribution networks mainly focus on the pre-disaster and post-disaster stages, relying on pre-disaster equipment reinforcement measures and post-disaster emergency resource deployment. There is no effective method for dynamically reconfiguring the distribution system during a disaster in the existing technology. Summary of the invention

[0006] The present invention provides a method for disaster reconstruction of a power distribution system taking into account network reconstruction and island division, so as to achieve effective disaster reconstruction and recovery of the power distribution system.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme.

[0008] A method for disaster reconstruction of a distribution system considering network reconstruction and island division, comprising:

[0009] Based on the distribution network topology, a mathematical model of dynamic network reconstruction and island division in a distribution system disaster is constructed, and the objective function and constraint conditions of the mathematical model of dynamic network reconstruction and island division are determined;

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

[0011] configuring a distributed power source 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 the 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.

[0013] Preferably, the mathematical model of network dynamic reconstruction and island division in a power distribution system disaster is constructed based on the power distribution network topology, and the objective function and constraint conditions of the mathematical model of network dynamic reconstruction and island division are determined, including:

[0014] Based on the distribution network topology, a mathematical model of network dynamic reconstruction and island division in a distribution system disaster is constructed. The objective function of the mathematical model of network dynamic reconstruction and island division 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 power distribution network;

[0017] The constraints of the dynamic reconstruction and islanding mathematical model in the distribution network disaster 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 a disaster, the capacity, voltage, and current of the faulty line must satisfy the following constraints:

[0021]

[0022] In the formula, during the period t, p j and q j They represent the active and reactive power injected into node j respectively; P and Q represent 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, grounding parallel conductance and susceptance respectively; v j represents the square of the voltage amplitude at node j; m ij is an auxiliary variable, taking the largest possible value;

[0023] The load shedding constraint is:

[0024]

[0025] The safe operation constraints are:

[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 constraints are:

[0030]

[0031] 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 segmentation 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;

[0032] The distributed power supply operation constraints are:

[0033]

[0034] in, They represent the lower and upper limits of the active power output of distributed generation, respectively. They represent the lower and upper limits of the reactive power output of distributed generation, respectively. 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 the disaster, including:

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

[0037] Preferably, the configuring of 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, They represent the lower and upper limits of the active power output of distributed generation, respectively. and They represent the lower and upper limits of the reactive power output of distributed generation, respectively. 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 optimal network reconstruction scheme is calculated by using a mathematical optimization method based on the structure, objective function and constraint conditions of the mathematical model of network reconstruction and island partitioning, the response of the distribution system during the disaster and the distributed power model configured in the system to minimize the load shedding and switch operation costs, including:

[0042] 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 the disaster and the distributed power model configured in the system, the optimal network reconstruction plan is calculated by using mathematical optimization methods to minimize the load shedding and switch operation costs, and 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 island areas; optimization of switch operation timing; load recovery strategy to ensure optimal load distribution; line flow analysis to prevent overload or voltage overlimit.

[0043] It can be seen from the technical solutions provided by the above-mentioned embodiments of the present invention that the method verifies the effectiveness of the model by testing the improved PG&E 69-node distribution system. The method improves the resilience of the distribution system during a disaster by allocating resources and reconstructing the network topology during the disaster stage 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 given in part in the following description, which will become obvious from the following description, or may be learned through 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 accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0046] Figure 1 A flowchart of a method for dynamic reconstruction of a power distribution system in a disaster taking into account network reconstruction and island division is provided in an embodiment of the present invention.

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

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

[0049] Figure 4 A diagram of the dynamic reconstruction process of the topology of a PG&E 69-node distribution network system during a network disaster 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 cannot be interpreted as limiting the present invention.

[0051] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "one", "said", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification 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, the "connection" or "coupling" used herein may include wireless connection or coupling. 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 those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[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] A flowchart of a method for dynamic reconstruction of a power distribution system in a disaster taking into account 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 in a distribution system disaster is constructed.

[0056] The objective function of the mathematical model of network dynamic reconstruction and island partitioning is set as 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 Represents the number of switches in the power distribution network.

[0060] The constraint conditions of the mathematical model of dynamic reconstruction and island division in the distribution network disaster include power flow constraint, load shedding constraint, safe operation constraint, radial topology constraint and distributed power supply operation constraint.

[0061] The power flow constraint is:

[0062]

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

[0064]

[0065] In the formula, during the period t, p j and q j They represent the active and reactive power injected into node j respectively; P and Q represent 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, grounding parallel conductance and susceptance respectively; v j represents the square of the voltage amplitude at node j; m ij is an auxiliary variable that 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 segmentation 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; in the process of island self-balancing control, the above formula proposes a single commodity flow constraint from the perspective of virtual power flow to ensure the connectivity of the graph. This can avoid the formation of an island with only one distributed power source. At the same time, it can achieve parallel optimization of network radiation constraints and interconnection constraints.

[0075] The distributed power supply operation constraints are:

[0076]

[0077] in, They represent the lower and upper limits of the active power output of distributed generation, respectively. They represent the lower and upper limits of the reactive power output of distributed generation, respectively. 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, the dynamic response of the distribution system during the disaster is calculated based on the network topology reconstruction optimization plan. At the same time, in step S4, the final network reconstruction plan is confirmed to ensure that load shedding is minimized and the switch 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 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 a temporary distribution network island, so as to restore 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, They represent the lower and upper limits of the active power output of distributed generation, respectively. and They represent the lower and upper limits of the reactive power output of distributed generation, respectively. 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 sources configured in the system can expand the power supply coverage of the distributed power sources beyond the adjacent nodes through the tie switches 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 switch operation costs.

[0087] Under the premise of ensuring the supply of important loads, balance the load shedding cost and switch operation cost of the distribution network to achieve a balance between load supply and cost. Determine the network reconstruction plan with the goal of minimizing the 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 of network reconstruction and island partitioning, with the goal of minimizing the load shedding and switch operation costs, the fault location is set as shown in Table 1 below, the optimal network reconstruction plan is calculated, and the switch status is dynamically adjusted during the disaster to balance the load shedding cost and power supply restoration capability.

[0090] The final dynamic reconstruction scheme results are shown in Table 2. The final dynamic reconstruction scheme includes: determination of island area; optimization of switch operation timing; load recovery strategy to ensure optimal load distribution; line flow analysis to prevent overload or voltage overrun.

[0091] Table 1 Statistics of faulty lines in different time periods

[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 to ensure the least load shedding. The objective function also considers: the priority of important loads to ensure the supply of important loads; the rationality of island division to maintain the stability of island power supply as much as possible; the cost of switch operation to reduce the impact of frequent switching on equipment.

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

[0097] The simulation of this embodiment is programmed using MATLAB R2021a and runs on a laptop with a 64-bit operating system, a 2.4GHz quad-core CPU, and 8GB of memory. To solve the MISOCP problem, the distribution network reconstruction model is 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 power 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 dotted lines, such as "11-43", "13-21", "15-46", "27-65" and "50-59". Figure 3 As shown. 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] In order to test the effect of post-disaster reconstruction, the research period is 4 hours after the disaster, and it is assumed that the distribution network is reconstructed once every hour. The statistics of fault lines in the system are shown in Table 3.

[0100] Table 3 Statistics of faulty lines in different time periods

[0101]

[0102] Figure 4 A diagram of a PG&E 69-node distribution network system topology dynamic reconstruction process in 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-off 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 (c) When the degree of power outage in the system increases, the system will actively cut off part of the load, 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. Figure 4 As shown in (d), the system interconnection switch 11-43 is actuated, and the node 44 is the island of the main node, so as to restore the 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 the existing methods, we used three different methods to set the fault scenario.

[0105] Scenario 1: Using the recovery model proposed by the present 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-node system contains more lines than the general distribution network. The dynamic reconstruction method proposed in this method can quickly and efficiently adjust the system topology during the fault evolution process, thereby achieving coordinated recovery of loads and 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, and significantly improve 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 reconstruct at all, this method shows superior economy and adaptability, and provides a new idea for feasibility and efficiency for large-scale distribution network disaster recovery.

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

[0114] At present, the research on improving the resilience of distribution networks at home and abroad mainly focuses on the two stages of pre-disaster and post-disaster, relying on equipment reinforcement measures before the disaster and emergency resource allocation after the disaster. However, the research on dynamic adjustment during the disaster is still relatively weak.

[0115] The present invention overcomes the limitation that the traditional virtual power flow constraint cannot optimize the connectivity constraint and the radial constraint at the same time, and solves the problem that the number of islands cannot be determined when dividing the islands, and avoids the limitation that the default island contains only one DG. Through the improved virtual power flow constraint, the present invention can more flexibly support the formation of multiple island areas (assuming that a total of q islands are formed), thereby formulating a better 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, have strong adaptability, and meet the timeliness requirements of real-time scheduling.

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

[0118] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present invention or certain parts of the embodiments.

[0119] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0120] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for power distribution system reconstruction during disaster considering network reconstruction and island division, characterized in that: include: Based on the distribution network topology, a mathematical model of dynamic network reconstruction and island division in a distribution system disaster is constructed, and the objective function and constraint conditions of the mathematical model of dynamic network reconstruction and island division are determined; Determine the response of the distribution system during a disaster based on the network reconstruction plan; configuring a distributed power source model in the power distribution system; 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 the 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.

2. The method according to claim 1, characterized in that The above-mentioned construction of a mathematical model for dynamic network reconstruction and island division in a power distribution system disaster based on the power distribution network topology and determination of the objective function and constraint conditions of the mathematical model for dynamic network reconstruction and island division include: Based on the distribution network topology, a mathematical model of network dynamic reconstruction and island division in a distribution system disaster is constructed. The objective function of the mathematical model of network dynamic reconstruction and island division 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, 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; The constraints of the dynamic reconstruction and islanding mathematical model in the distribution network 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 faulty line must satisfy the following constraints: In the formula, during the period t, p j and q j They represent the active and reactive power injected into node j respectively; P and Q represent 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, grounding parallel conductance and susceptance respectively; v j represents the square of the voltage amplitude at node j; m ij is an auxiliary variable, taking 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 segmentation 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 distributed generation, respectively. They represent the lower and upper limits of the reactive power output of distributed generation, respectively. 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 network-based reconstruction scheme determines the response of the power distribution system during a disaster, including: Based on the structure of the mathematical model of network reconstruction and island division, the distribution network reconstruction and optimization are carried out during the disaster, the interconnection lines in the distribution network are adjusted, the output characteristics of the distributed power sources are used to connect with the load to form a temporary distribution network island, and the load is restored.

4. The method according to claim 3, characterized in that The configuration of the distributed power supply model in the power distribution system includes: The distributed power supply model configured in the power distribution system is as follows: in, They represent the lower and upper limits of the active power output of distributed generation, respectively. and They represent the lower and upper limits of the reactive power output of distributed generation, respectively. 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.

5. The method according to claim 4, characterized in that The structure, objective function and constraint conditions of the mathematical model of network reconstruction and island partitioning, the response of the distribution system during the disaster and the distributed power model configured in the system are used to calculate the optimal network reconstruction plan by using a mathematical optimization method to minimize the load shedding and switch operation costs, including: 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 the disaster and the distributed power model configured in the system, the optimal network reconstruction plan is calculated by using mathematical optimization methods to minimize the load shedding and switch operation costs, and 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 island areas; optimization of switch operation timing; load recovery strategy to ensure optimal load distribution; line flow analysis to prevent overload or voltage overlimit.

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