Power grid fault repairing method and device based on network reconstruction and island division

Abstract

The invention discloses a power grid fault repairing method and device based on network reconstruction and island division. The method comprises the following steps: adding a radiation constraint and a connectivity constraint to island division of a power distribution network, and adding a line recovery constraint and a power flow constraint to reconstruction of the power distribution network; carrying out island division and network reconstruction on the power distribution network at the same time, and establishing a power grid fault repair model by taking the minimum load loss capacity of the power distribution network as an objective function; performing simplification processing on the power grid fault repair model by adopting a large M method, and performing second-order cone relaxation on the line recovery constraint and the power flow constraint to obtain a power grid fault repair simplified model; solving the power grid fault repair simplified model to obtain a power distribution network topology scheme with the minimum load loss capacity; island division and network reconstruction are carried out at the same time to complete power grid fault recovery, existing network resources can be fully utilized in the recovery process, and meanwhile the load loss amount is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power systems, and in particular relates to a method and a device for repairing power grid faults based on network reconstruction and island division. Background Art

[0002] With the transformation of the global energy structure and the rapid development of renewable energy, the stability and reliability of the distribution system, as an important part of the power system, are facing unprecedented challenges. Especially in the context of frequent extreme weather, the distribution system often suffers from large-scale failures such as line disconnection and tower collapse, which seriously affects the continuity and safety of power supply. Therefore, how to quickly restore the power supply capacity of the distribution system in the event of a large-scale failure has become an urgent problem to be solved in the power industry.

[0003] Traditional distribution system fault recovery strategies mainly focus on two aspects: islanding and network reconstruction. Islanding means dividing the distribution system into several independent parts when a fault occurs, and each part is as self-sufficient as possible to maintain local power supply. Network reconstruction means optimizing the topology of the distribution network and reconfiguring the lines and switches to improve the power supply capacity and reliability of the system.

[0004] However, existing methods often treat island partitioning and network reconstruction as two independent steps. The island partitioning process often ignores the importance of network reconstruction, resulting in the inability to fully utilize existing network resources during the recovery process. At the same time, when large-scale failures occur, due to the lack of effective network reconstruction strategies, many load nodes cannot resume power supply in time, resulting in large load loss. Summary of the invention

[0005] The present invention provides a method and device for repairing power grid faults based on network reconstruction and island division, which simultaneously performs island division and network reconstruction to complete power grid fault repair, and can fully utilize existing network resources during the recovery process while reducing the amount of load loss.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A first aspect of the present invention provides a power grid fault repair method based on network reconstruction and island division, comprising:

[0008] Traversing the power distribution network to obtain electrical connection relationships and fault line information; the power distribution network includes load nodes and distributed power sources, and determining the power consumption demand of each load node and the maximum power generation of the distributed power source;

[0009] Add radiation constraints to the islanding of the distribution network based on the electrical connection relationship and fault line information, and add line recovery constraints to the reconstruction of the distribution network; add connectivity constraints to the islanding of the distribution network based on the power demand of each load node and the maximum power generation of the distributed power source, and add power flow constraints to the reconstruction of the distribution network;

[0010] The distribution network is islanded and reconstructed at the same time, and a power grid fault repair model is established with the minimum load loss of the distribution network as the objective function;

[0011] The big M method is used to simplify the power grid fault repair model, and the line restoration constraints and power flow constraints are relaxed by second-order cones to obtain the simplified power grid fault repair model; the simplified power grid fault repair model is solved to obtain the distribution network topology scheme with the minimum load loss.

[0012] Furthermore, based on the electrical connection relationship and fault line information, radial constraints are added to the islanding of the distribution network. The process includes:

[0013] The electrical connection relationship of the power distribution network includes the connection relationship between the load node and the distributed power source; the fault line information includes the fault line number and the fault occurrence time period;

[0014] Determine the regional division index of the segmented area according to the fault line number, fault occurrence period, and the connection relationship between the load node and the distributed power source; construct a variable matrix based on the regional division index , the expression formula is ; It is a regional division indicator used to determine whether there is power supply during the t period The segmented area in which it is located; Indicates the number of power supplies; Indicates the total number of failure periods;

[0015] According to the electrical connection relationship and fault line information, it is determined whether the load node is in the segmentation area to obtain the node division index, and the variable three-dimensional space is constructed according to the node division index. , the expression formula is: ; Represents the node division index, which is used to determine the t period. Is the load node in power supply? The segmented area in which it is located; Indicates the number of load nodes;

[0016] According to the variable three-dimensional space and the variable matrix Add radiation constraints to the island division of the distribution network, and the expression formula is:

[0017] ;

[0018] ;

[0019] ;

[0020] ;

[0021] In the formula, B represents the set of all load nodes in the distribution network; It is represented as the total substation node set in the distribution network; i is represented as the serial number of the load node; Represented as the collection of power sources in the power distribution network; It is a node set in the power distribution network excluding substation nodes.

[0022] Furthermore, connectivity constraints are added to the islanding of the distribution network based on the power demand of each load node and the maximum power generation of the distributed generation. The process includes:

[0023] ;

[0024] ;

[0025] ;

[0026] ;

[0027] ;

[0028] In the formula, is the virtual output power of power source o in the segmented area at time t; j, k are the serial numbers of the load nodes; is the line virtual power in the segmented area with the i-th load node as the starting node, the j-th load node as the ending node, and the power source o at time t; is the line virtual power in the segmented area with the i-th load node as the starting node, the k-th load node as the ending node, and the power source o at time t; is the virtual load of the jth load node at time t; is the virtual load of the kth load node; is the line virtual power with the i-th load node as the starting node and the j-th load node as the ending node; is the maximum value of virtual output power of power source o; is the on-off state of the fault line from the i-th load node to the j-th load node at time t; W is the line set.

[0029] Furthermore, based on the electrical connection relationship and the fault line information, line restoration constraints are added to the distribution network reconstruction, and the process includes:

[0030] ;

[0031] ;

[0032] ;

[0033] In the formula, is the initial state of the fault line from the i-th load node to the j-th load node; For the fault line set: is the set of non-fault lines; is the normal initial state of the line from the i-th load node to the j-th load node; for The on-off status of the fault line from the i-th load node to the j-th load node at the time; for The on-off status of the fault line from the i-th load node to the j-th load node at the time; is the set unit time period; K is the maximum number of restored lines in each unit time period; is the set of lines with switches in the distribution network at the initial moment.

[0034] Furthermore, based on the power demand of each load node and the maximum power generation of the distributed generation, power flow constraints are added to the distribution network reconstruction. The process includes:

[0035] ;

[0036] ;

[0037] ;

[0038] In the formula, is the set of parent nodes connected to the jth load node; is the set of child nodes connected to the jth load node; is the total active power injected into the jth load node at time t; is the total outflow active power of the jth load node at time t; is the active load of the jth load node at time t; is the active output power of the distributed generation to the jth load node at time t; is the active load loss of the jth load node at time t; is the active load power from the i-th load node to the j-th load node; is the square term of the line current from the i-th load node to the j-th load node at time t; is the resistance value of the line from the i-th load node to the j-th load node; is the total reactive power injected into the jth load node at time t; is the total reactive power outflow from the jth load node at time t; is the reactive load of the jth load node at time t; is the reactive output power of the distributed generation to the jth load node at time t; is the reactive load loss of the jth load node at time t; is the reactive load power from the i-th load node to the j-th load node; is the line loss resistance from the i-th load node to the j-th load node; and are the square terms of the voltages of the i-th load node and the j-th load node at time t respectively; It is the square term of the active power of the line from the i-th load node to the j-th load node at time t; It is the square term of the reactive power of the line from the i-th load node to the j-th load node at time t.

[0039] Furthermore, the distribution network is islanded and reconstructed at the same time, and a power grid fault repair model is established with the minimum load loss of the distribution network as the objective function. The process includes:

[0040]

[0041] In the formula, Indicates the total number of failure periods; represents the load loss of the i-th load node at time t; is the total load loss; B is the node set of the distribution network.

[0042] Furthermore, the large M method is used to simplify the power grid fault repair model, and the line restoration constraints and power flow constraints are relaxed by second-order cones. The process includes:

[0043] After simplifying the power grid fault repair model using the Big M method, the intermediate variable and Substituting the voltage squared term and ; Introduce intermediate variables Substituting the square of the current , perform second-order cone relaxation on the line restoration constraint and power flow constraint, and the expression formula is:

[0044] ;

[0045] ;

[0046] ;

[0047] ;

[0048] In the formula, M is a set positive constant; It is the total set of lines with switches in the distribution network.

[0049] A second aspect of the present invention provides a power grid fault repair device based on network reconstruction and island division, comprising:

[0050] An acquisition unit, used to traverse the distribution network to acquire electrical connection relationships and fault line information; the distribution network includes load nodes and distributed power sources, and determines the power consumption demand of each load node and the maximum power generation of the distributed power source;

[0051] The island division limiting unit adds radiation constraints to the island division of the distribution network based on the electrical connection relationship and fault line information; adds connectivity constraints to the island division of the distribution network based on the power demand of each load node and the maximum power generation of the distributed power source;

[0052] The network reconstruction limiting unit adds line restoration constraints to the distribution network reconstruction based on the electrical connection relationship and fault line information; adds power flow constraints to the distribution network reconstruction based on the power demand of each load node and the maximum power generation of the distributed power source;

[0053] The model building unit simultaneously performs island division and network reconstruction on the distribution network, and establishes a power grid fault repair model with the minimum load loss of the distribution network as the objective function;

[0054] The computing processing unit uses the big M method to simplify the power grid fault repair model, and performs second-order cone relaxation on the line restoration constraints and the power flow constraints to obtain the simplified power grid fault repair model; the simplified power grid fault repair model is solved to obtain the distribution network topology solution with the minimum load loss.

[0055] Furthermore, the model building unit simultaneously performs island division and network reconstruction on the distribution network, and establishes a power grid fault repair model with the minimum load loss of the distribution network as the objective function, and the process includes:

[0056]

[0057] In the formula, Indicates the total number of failure periods; represents the load loss of the i-th load node at time t; is the total load loss; B is the node set of the distribution network.

[0058] The third aspect of the present invention provides an electronic device, comprising a storage medium and a processor; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the power grid fault repair method based on network reconstruction and island division as described in the first aspect.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] The present invention adds radiation constraints and connectivity constraints to the island division of the distribution network; the radiation constraints ensure that the network structure within each island is tree-like, which helps to prevent potential feedback current and voltage instability problems, thereby improving the stability of the system; through the connectivity constraints, it can be ensured that all nodes in the island can receive electricity, thereby more reasonably allocating power resources and improving resource utilization efficiency.

[0061] The present invention adds line recovery constraints and power flow constraints to the reconstruction of the distribution network. The line recovery constraints allow the system to quickly identify and restore key lines after a fault occurs, thereby accelerating the restoration of power supply and reducing power outage time; the power flow constraints ensure the balance between power supply and demand, prevent overload and voltage instability, and ensure the continuity of power supply.

[0062] The present invention simultaneously performs island division and network reconstruction on the distribution network to adapt to different fault conditions and network structures, so as to better integrate distributed power generation resources and improve the utilization efficiency of these resources; establishing a power grid fault repair model with the minimum load loss of the distribution network as the objective function can minimize the impact of power outages and ensure the power supply of key users and loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a flow chart of a power grid fault repair method based on network reconstruction and island division provided in Example 1 of the present invention;

[0064] Figure 2 is a fault topology diagram of a power distribution network provided in Embodiment 1 of the present invention;

[0065] Figure 3 It is a distribution network fault recovery topology diagram of the first period in the prior art method of first island division and then reconstruction;

[0066] Figure 4 It is a distribution network fault recovery topology diagram of the second period in the prior art method of first island division and then reconstruction;

[0067] Figure 5 It is a distribution network fault recovery topology diagram of the third period in the prior art method of first island division and then reconstruction;

[0068] Figure 6is a distribution network fault recovery topology diagram of the first period in embodiment 1 of the present invention;

[0069] Figure 7 is a topological structure diagram of a power distribution network fault recovery in the second period in the first embodiment of the present invention;

[0070] Figure 8 It is a distribution network fault recovery topology diagram of the third period in Example 1 of the present invention. DETAILED DESCRIPTION

[0071] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0072] Example 1

[0073] like Figure 1 As shown, this implementation provides a power grid fault repair method based on network reconstruction and island division, including:

[0074] Traversing the power distribution network to obtain electrical connection relationships and fault line information; the power distribution network includes load nodes and distributed power sources, and determining the power consumption demand of each load node and the maximum power generation of the distributed power source;

[0075] Adding radial constraints to the islanding of the distribution network based on the electrical connection relationship and fault line information includes:

[0076] The electrical connection relationship of the power distribution network includes the connection relationship between the load node and the distributed power source; the fault line information includes the fault line number and the fault occurrence time period;

[0077] Determine the regional division index of the segmented area according to the fault line number, fault occurrence period, and the connection relationship between the load node and the distributed power source; construct a variable matrix based on the regional division index , the expression formula is ; It is a regional division indicator used to determine whether there is power supply during the t period The segmented area in which it is located; Indicates the number of power supplies; Indicates the total number of failure periods;

[0078] According to the electrical connection relationship and fault line information, it is determined whether the load node is in the segmentation area to obtain the node division index, and the variable three-dimensional space is constructed according to the node division index. , the expression formula is: ; Represents the node division index, which is used to determine the t period. Is the load node in power supply? The segmented area in which it is located; Indicates the number of load nodes;

[0079] According to the variable three-dimensional space and the variable matrix Add radiation constraints to the island division of the distribution network, and the expression formula is:

[0080] ; (1)

[0081] ; (2)

[0082] ; (3)

[0083] ; (4)

[0084] In the formula, B represents the set of all load nodes in the distribution network; It is represented as the total substation node set in the distribution network; i is represented as the serial number of the load node; Represented as the collection of power sources in the power distribution network; It is a node set in the power distribution network excluding substation nodes.

[0085] Formula (1) indicates that when there is a split area, the load node It may be inside the partition area or outside the partition area; Formula (2) indicates that each load node belongs to and only belongs to one partition area; Formula (3) indicates that the nodes in the partition area are connected to other nodes by at least one path; Formula (4) indicates that the power source point must be in the partition area to which it belongs.

[0086] Add connectivity constraints to the islanding of the distribution network based on the power demand of each load node and the maximum power generation of the distributed generation. The process includes:

[0087] ; (5)

[0088] ; (6)

[0089] ; (7)

[0090] ; (8)

[0091] ; (9)

[0092] In the formula, is the virtual output power of power source o in the segmented area at time t; j, k are the serial numbers of the load nodes; is the line virtual power in the segmented area with the i-th load node as the starting node, the j-th load node as the ending node, and the power source o at time t; is the line virtual power in the segmented area with the i-th load node as the starting node, the k-th load node as the ending node, and the power source o at time t; is the virtual load of the jth load node at time t; is the virtual load of the kth load node; is the line virtual power with the i-th load node as the starting node and the j-th load node as the ending node; is the maximum value of virtual output power of power source o; is the on-off state of the fault line from the i-th load node to the j-th load node at time t; W is the line set; Formula (5) represents the output constraint of power source o in the split area during time period t; Formula (6) is the virtual power capacity constraint of the line in the split area with o as the power source point; Formula (7) indicates that the virtual load of the nodes other than power source o in each split area is 1; Formula (8) is the power balance constraint in the split area. Formula (9) is the radial constraint of the split area, indicating that the number of branches running in quantity is equal to the number of nodes minus the number of split areas.

[0093] Based on the electrical connection relationship and fault line information, the distribution network reconstruction adds line restoration constraints. The process includes:

[0094] ; (10)

[0095] ; (11)

[0096] ; (12)

[0097] In the formula, is the initial state of the fault line from the i-th load node to the j-th load node; For the fault line set: is the set of non-fault lines; is the normal initial state of the line from the i-th load node to the j-th load node; for The on-off status of the fault line from the i-th load node to the j-th load node at the time; for The on-off status of the fault line from the i-th load node to the j-th load node at the time; is the set unit time period; K is the maximum number of restored lines in each unit time period; is the set of lines with switches in the distribution network at the initial moment. Formula (10) shows that the faulty line is in a disconnected state at the initial moment; Formula (11) shows that the switch is no longer turned on after the faulty line is repaired, ensuring that each switch operation in the system during the recovery process is non-redundant; Formula (12) shows that at most K lines can be restored in each time period

[0098] Based on the power demand of each load node and the maximum power generation of distributed generation, power flow constraints are added to the distribution network reconstruction. The process includes:

[0099] ; (13)

[0100] ; (14)

[0101] ; (15)

[0102] In the formula, is the set of parent nodes connected to the jth load node; is the set of child nodes connected to the jth load node; is the total active power injected into the jth load node at time t; is the total outflow active power of the jth load node at time t; is the active load of the jth load node at time t; is the active output power of the distributed generation to the jth load node at time t; is the active load loss of the jth load node at time t; is the active load power from the i-th load node to the j-th load node; is the square term of the line current from the i-th load node to the j-th load node at time t; is the resistance value of the line from the i-th load node to the j-th load node; is the total reactive power injected into the jth load node at time t; is the total reactive power outflow from the jth load node at time t; is the reactive load of the jth load node at time t; is the reactive output power of the distributed generation to the jth load node at time t; is the reactive load loss of the jth load node at time t; is the reactive load power from the i-th load node to the j-th load node; is the line loss resistance from the i-th load node to the j-th load node; and are the square terms of the voltages of the i-th load node and the j-th load node at time t respectively; It is the square term of the active power of the line from the i-th load node to the j-th load node at time t; It is the square term of the reactive power of the line from the i-th load node to the j-th load node at time t.

[0103] The distribution network is islanded and reconstructed at the same time, and a power grid fault repair model is established with the minimum load loss of the distribution network as the objective function. The process includes:

[0104]

[0105] In the formula, Indicates the total number of failure periods; represents the load loss of the i-th load node at time t; is the total load loss; B is the node set of the distribution network.

[0106] The big M method is used to simplify the power grid fault repair model, where the line restoration constraints are as follows:

[0107] ;

[0108] like 1 indicates that the switch is closed. 0 means the switch is on. The circuit is disconnected by the switch; , , The values ​​are all 0, indicating that there is no current and power transmission in this branch, and no power flow calculation is required. Therefore, the power flow constraint of the switch disconnecting the line can be removed.

[0109] The power flow constraints are as follows:

[0110] ;

[0111] Introducing intermediate variables and Substituting the voltage squared term and ; Introduce intermediate variables Substituting the square of the current , perform second-order cone relaxation on the line restoration constraint and power flow constraint, and the expression formula is:

[0112] ;

[0113] ; ;

[0114] ;

[0115] In the formula, M is a set positive constant; A collection of lines with switches in a power distribution network.

[0116] The simplified model of power grid fault repair is solved to obtain the distribution network topology solution with the minimum load loss.

[0117] In this implementation, the objective function is to minimize the amount of load loss in the distribution system, and a power grid fault repair model for large-scale fault scenarios of the distribution system is established. The simplified power grid fault repair model that unifies reconstruction and islanding is converted into a mixed integer second-order cone programming form through the large M method and second-order cone relaxation, and a simplified linear constraint set is obtained, which reduces the solution space of the reconstruction problem. By comparing the distribution network topology schemes in the scenario of first islanding and then reconstruction, the results show that optimizing the switch selection strategy after the distribution system fault can reasonably improve the utilization rate of distributed energy, solve the problem of large load loss in the reconstruction of large-scale faults in the distribution system, and improve the fault recovery efficiency of the distribution system.

[0118] like Figure 2 As shown, in this embodiment, the improved IEEE-33 node system is taken as the fault topology diagram of the distribution network, the entire distribution network is traversed and the number of load nodes in the distribution network is determined to be 33 and the load nodes are numbered. To facilitate the calculation of radial distribution network flow, it is necessary to satisfy that the upstream node number is less than the downstream node number. The section branch is between load node 1 and load node 2, represented by solid line 1; the connecting branch is between load node 8 and load node 21, represented by dotted line 33, and so on. Solid lines 1-32 represent section branches, and dotted lines 33-37 represent connecting branches.

[0119] Table 1, Distributed Generation Installation Location and Capacity;

[0120]

[0121] The total active load of the IEEE-33 node system is 3802.19kW, the total reactive load is 2694.6kvar, the network voltage reference value is 12.66kV, and the apparent power reference value is 100MVA. The power of the distributed generation is assumed to be constant over time, and the specific values ​​are shown in Table 1 below. It is assumed that all branches are equipped with remote section switches. The fault line numbers are: lines 2, 5, 14, 19, 23, and 32.

[0122] In order to illustrate the effectiveness of the proposed embodiment in reducing the amount of load loss, the following two scenarios are designed:

[0123] Scenario 1: Figures 6 to 8 As shown, the method provided in this embodiment is selected to repair the fault of the power distribution network.

[0124] Scenario 2: If Figures 3 to 5 As shown, the method of first islanding and then reconstructing the network is selected to repair the distribution network fault.

[0125] In this embodiment, the power grid fault repair model takes the minimum load loss as the objective function, adopts a linearized simplified model, is built on the yalmip platform, and calls the gurobi solver to solve the IEEE 33-node system with renewable distributed generation (RDG) added, and obtains the optimal solution for the fault reconstruction of the distribution system. Considering that the 33-node system repairs one line in each period, performs one reconstruction and island division, the fault lines 2, 5, 14, 19, 23, and 32 in the distribution system need to undergo six repairs, and the results are shown in Table 2.

[0126] Table 2, Distribution network reconstruction scheme;

[0127]

[0128] It can be seen from Table 2 that in period 1, scenario 1: first island division and then reconstruction, disconnect switch numbers 2, 5, 14, 19, 23, 32, 33, 34, 35, 36, 37, and the load loss is 885kW; scenario 2: network reconstruction and island division are performed at the same time, and switch numbers 2, 5, 14, 19, 23, 32, 34, 35, 36 are disconnected, and the load loss is 825kW. Compared with scenario 1, the load loss in scenario 2 is reduced by 60kW. It shows that simultaneous network reconstruction and island division can significantly reduce the load loss of the distribution system containing distributed generation. In addition, although the load loss of the distribution network is decreasing as the line fault gradually recovers, the simultaneous network reconstruction and island division reduce the load loss of the distribution network more, and in the third period, the load loss is 0, and the power grid recovery efficiency is higher.

[0129] By comparing the load loss results of the two scenarios, it can be seen that this embodiment can effectively improve the fault recovery operation of the distribution network, reduce the load loss of large-scale faults in the distribution network, significantly improve the reliability of the distribution network, and improve the recovery efficiency of the distribution network during faults.

[0130] Example 2

[0131] like Figure 7 The present embodiment provides a power grid fault repairing device based on network reconstruction and island division. The power grid fault repairing device described in the present embodiment can be used to execute the power grid fault repairing method described in Example 1. The power grid fault repairing system includes:

[0132] An acquisition unit, used to traverse the distribution network to acquire electrical connection relationships and fault line information; the distribution network includes load nodes and distributed power sources, and determines the power consumption demand of each load node and the maximum power generation of the distributed power source;

[0133] The island division limiting unit adds radiation constraints to the island division of the distribution network based on the electrical connection relationship and fault line information; adds connectivity constraints to the island division of the distribution network based on the power demand of each load node and the maximum power generation of the distributed power source;

[0134] The network reconstruction limiting unit adds line restoration constraints to the distribution network reconstruction based on the electrical connection relationship and fault line information; adds power flow constraints to the distribution network reconstruction based on the power demand of each load node and the maximum power generation of the distributed power source;

[0135] The model building unit simultaneously performs island division and network reconstruction on the distribution network, and establishes a power grid fault repair model with the minimum load loss of the distribution network as the objective function;

[0136] The computing processing unit uses the big M method to simplify the power grid fault repair model, and performs second-order cone relaxation on the line restoration constraints and the power flow constraints to obtain the simplified power grid fault repair model; the simplified power grid fault repair model is solved to obtain the distribution network topology solution with the minimum load loss.

[0137] The model building unit simultaneously performs island division and network reconstruction on the distribution network, and establishes a power grid fault repair model with the minimum load loss of the distribution network as the objective function. The process includes:

[0138]

[0139] In the formula, Indicates the total number of failure periods; represents the load loss of the i-th load node at time t; is the total load loss; B is the node set of the distribution network.

[0140] Example 3

[0141] This embodiment provides an electronic device, including a storage medium and a processor; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the power grid fault repair method based on network reconstruction and island division described in Example 1.

[0142] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0143] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0144] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0145] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0146] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for repairing power grid faults based on network reconstruction and island division, characterized in that: include: Traverse the power distribution network to obtain electrical connection relationships and fault line information; The power distribution network includes load nodes and distributed power sources, and the power consumption demand of each load node and the maximum power generation of the distributed power source are determined; Add radiation constraints to the islanding of the distribution network based on the electrical connection relationship and fault line information, and add line recovery constraints to the reconstruction of the distribution network; add connectivity constraints to the islanding of the distribution network based on the power demand of each load node and the maximum power generation of the distributed power source, and add power flow constraints to the reconstruction of the distribution network; The distribution network is islanded and reconstructed at the same time, and a power grid fault repair model is established with the minimum load loss of the distribution network as the objective function; The big M method is used to simplify the power grid fault repair model, and the line restoration constraints and power flow constraints are relaxed by second-order cones to obtain the simplified power grid fault repair model; the simplified power grid fault repair model is solved to obtain the distribution network topology scheme with the minimum load loss.

2. The power grid fault repair method according to claim 1, characterized in that: Adding radial constraints to the islanding of the distribution network based on the electrical connection relationship and fault line information includes: The electrical connection relationship of the power distribution network includes the connection relationship between the load node and the distributed power source; the fault line information includes the fault line number and the fault occurrence time period; Determine the regional division index of the segmented area according to the fault line number, fault occurrence period, and the connection relationship between the load node and the distributed power source; construct a variable matrix based on the regional division index , the expression formula is ; It is a regional division indicator used to judge Time period, whether there is power supply The segmented area in which it is located; Indicates the number of power supplies; Indicates the total number of failure periods; According to the electrical connection relationship and fault line information, it is determined whether the load node is in the segmentation area to obtain the node division index, and the variable three-dimensional space is constructed according to the node division index. , the expression formula is: ; Indicates the node division index, used to judge Period, i Is the load node in power supply? The segmented area in which it is located; Indicates the number of load nodes; According to the variable three-dimensional space and the variable matrix Add radiation constraints to the island division of the distribution network, and the expression formula is: ； ； ； ； In the formula, B represents the set of all load nodes in the distribution network; It is represented as the total substation node set in the distribution network; i is represented as the serial number of the load node; Represented as the collection of power sources in the power distribution network; It is a node set in the power distribution network excluding substation nodes.

3. The power grid fault repair method according to claim 2, characterized in that: Add connectivity constraints to the islanding of the distribution network based on the power demand of each load node and the maximum power generation of the distributed generation. The process includes: ； ； ； ； ； In the formula, is the virtual output power of power source o in the segmented area at time t; j, k are the serial numbers of the load nodes; is the line virtual power in the segmented area with the i-th load node as the starting node, the j-th load node as the ending node, and the power source o at time t; is the line virtual power in the segmented area with the i-th load node as the starting node, the k-th load node as the ending node, and the power source o at time t; is the virtual load of the jth load node at time t; is the virtual load of the kth load node; is the line virtual power with the i-th load node as the starting node and the j-th load node as the ending node; is the maximum value of virtual output power of power source o; is the on-off state of the fault line from the i-th load node to the j-th load node at time t; W is the line set.

4. The method for repairing a power grid fault according to claim 3, characterized in that: Based on the electrical connection relationship and fault line information, the distribution network reconstruction adds line restoration constraints. The process includes: ； ； ； In the formula, is the initial state of the fault line from the i-th load node to the j-th load node; For the fault line set: is the set of non-fault lines; is the normal initial state of the line from the i-th load node to the j-th load node; for The on-off status of the fault line from the i-th load node to the j-th load node at the time; for The on-off status of the fault line from the i-th load node to the j-th load node at the time; is the set unit time period; K is the maximum number of restored lines in each unit time period; is the set of lines with switches in the distribution network at the initial moment.

5. The method for repairing a power grid fault according to claim 4, characterized in that: Based on the power demand of each load node and the maximum power generation of distributed generation, power flow constraints are added to the distribution network reconstruction. The process includes: ； ； ； In the formula, is the set of parent nodes connected to the jth load node; is the set of child nodes connected to the jth load node; is the total active power injected into the jth load node at time t; is the total outflow active power of the jth load node at time t; is the active load of the jth load node at time t; is the active output power of the distributed generation to the jth load node at time t; is the active load loss of the jth load node at time t; is the active load power from the i-th load node to the j-th load node; is the square term of the line current from the i-th load node to the j-th load node at time t; is the resistance value of the line from the i-th load node to the j-th load node; is the total reactive power injected into the jth load node at time t; is the total reactive power outflow from the jth load node at time t; is the reactive load of the jth load node at time t; is the reactive output power of the distributed generation to the jth load node at time t; is the reactive load loss of the jth load node at time t; is the reactive load power from the i-th load node to the j-th load node; is the line loss resistance from the i-th load node to the j-th load node; and are the square terms of the voltages of the i-th load node and the j-th load node at time t respectively; It is the square term of the active power of the line from the i-th load node to the j-th load node at time t; It is the square term of the reactive power of the line from the i-th load node to the j-th load node at time t.

6. The power grid fault repair method according to any one of claims 1 to 5, characterized in that: The distribution network is islanded and reconstructed at the same time, and a power grid fault repair model is established with the minimum load loss of the distribution network as the objective function. The process includes: ； In the formula, Indicates the total number of failure periods; represents the load loss of the i-th load node at time t; is the total load loss; B is the node set of the distribution network.

7. The method for repairing a power grid fault according to claim 5, characterized in that: The large M method is used to simplify the power grid fault repair model, and the line restoration constraints and power flow constraints are relaxed by second-order cones. The process includes: After simplifying the power grid fault repair model using the Big M method, the intermediate variable and Substituting the voltage squared term and ; Introduce intermediate variables Substituting the square of the current , perform second-order cone relaxation on the line restoration constraint and power flow constraint, and the expression formula is: ； ； ； ； In the formula, M is a set positive constant; It is the total set of lines with switches in the distribution network.

8. A power grid fault repair device based on network reconstruction and island division, characterized in that: include: An acquisition unit, used for traversing the power distribution network to acquire electrical connection relations and fault line information; The power distribution network includes load nodes and distributed power sources, and the power consumption demand of each load node and the maximum power generation of the distributed power source are determined; The island division limiting unit adds radiation constraints to the island division of the distribution network based on the electrical connection relationship and fault line information; adds connectivity constraints to the island division of the distribution network based on the power demand of each load node and the maximum power generation of the distributed power source; The network reconstruction limiting unit adds line restoration constraints to the distribution network reconstruction based on the electrical connection relationship and fault line information; adds power flow constraints to the distribution network reconstruction based on the power demand of each load node and the maximum power generation of the distributed power source; The model building unit simultaneously performs island division and network reconstruction on the distribution network, and establishes a power grid fault repair model with the minimum load loss of the distribution network as the objective function; The computing processing unit uses the big M method to simplify the power grid fault repair model, and performs second-order cone relaxation on the line restoration constraints and the power flow constraints to obtain the simplified power grid fault repair model; the simplified power grid fault repair model is solved to obtain the distribution network topology solution with the minimum load loss.

9. The power grid fault repairing device according to claim 8, characterized in that: The model building unit simultaneously performs island division and network reconstruction on the distribution network, and establishes a power grid fault repair model with the minimum load loss of the distribution network as the objective function. The process includes: ； In the formula, Indicates the total number of failure periods; represents the load loss of the i-th load node at time t; is the total load loss; B is the node set of the distribution network.

10. An electronic device comprising a storage medium and a processor; the storage medium is used to store instructions; characterized in that: The processor is used to operate according to the instructions to execute the power grid fault repair method based on network reconstruction and island division as described in any one of claims 1 to 7.

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