Power distribution network fault isolation method, electronic equipment and storage medium

Abstract

The embodiment of the invention discloses a power distribution network fault isolation method, electronic equipment and a storage medium. The method comprises the following steps: for a power distribution network to be subjected to fault isolation, determining an initial island division scheme based on a power grid network structure of the power distribution network and a fault area in the power distribution network; optimizing the initial island division scheme based on a preset cuckoo search algorithm to obtain an optimized island division scheme, and optimizing the optimized island division scheme based on a preset simulated annealing algorithm to obtain a target island division scheme; and isolating the fault area based on the target island division scheme. According to the technical scheme of the embodiment of the invention, the influence of the power distribution network fault on the whole power distribution network area can be reduced to the greatest extent.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of power failure, and in particular to a distribution network fault isolation method, electronic equipment and storage medium. Background Art

[0002] After a distribution network failure occurs, an island division plan can be formulated to isolate the faulty area and restore power supply to the non-faulty area, thereby reducing the impact of the distribution network failure on the entire distribution network area.

[0003] However, with existing technical means, it is difficult to determine the optimal island division scheme in the global scope of the distribution network, the fault isolation effect is poor, and the impact of distribution network faults on the entire distribution network area cannot be minimized, which urgently needs to be solved. Summary of the invention

[0004] The embodiments of the present invention provide a distribution network fault isolation method, an electronic device and a storage medium to minimize the impact of a distribution network fault on the entire distribution network area.

[0005] According to one aspect of the present invention, a method for isolating a distribution network fault is provided, which may include:

[0006] For the distribution network to be isolated for fault, an initial island division scheme is determined based on the network structure of the distribution network and the fault area in the distribution network;

[0007] The initial island partitioning scheme is optimized based on a preset cuckoo search algorithm to obtain an optimized island partitioning scheme, and the optimized island partitioning scheme is optimized based on a preset simulated annealing algorithm to obtain a target island partitioning scheme;

[0008] Isolate the fault area based on the target island partitioning scheme.

[0009] According to another aspect of the present invention, a distribution network fault isolation device is provided, which may include:

[0010] An initial island partitioning scheme determination module is used to determine an initial island partitioning scheme for a distribution network to be isolated for faults based on the network structure of the distribution network and the fault area in the distribution network;

[0011] The module for obtaining the initial island partitioning scheme is used to optimize the initial island partitioning scheme based on a preset cuckoo search algorithm to obtain an optimized island partitioning scheme, and to optimize the optimized island partitioning scheme based on a preset simulated annealing algorithm to obtain a target island partitioning scheme;

[0012] The fault area isolation module is used to isolate the fault area based on the target island division scheme.

[0013] According to another aspect of the present invention, there is provided an electronic device, which may include:

[0014] at least one processor; and

[0015] a memory communicatively connected to at least one processor; wherein,

[0016] The memory stores a computer program that can be executed by at least one processor. The computer program is executed by at least one processor so that the at least one processor implements the distribution network fault isolation method provided by any embodiment of the present invention when executing the computer program.

[0017] According to another aspect of the present invention, a computer-readable storage medium is provided, on which computer instructions are stored. The computer instructions are used to enable a processor to implement the distribution network fault isolation method provided by any embodiment of the present invention when executed.

[0018] The technical solution of the embodiment of the present invention is to determine the initial island partitioning scheme based on the network structure of the distribution network and the fault area in the distribution network for the distribution network to be isolated from the fault, so as to complete the preliminary partitioning of the island; optimize the initial island partitioning scheme based on the preset cuckoo search algorithm to obtain the optimized island partitioning scheme, and optimize the optimized island partitioning scheme based on the preset simulated annealing algorithm to obtain the target island partitioning scheme, so as to optimize the initial island partitioning scheme step by step within the global scope of the distribution network and determine the optimal island partitioning scheme; isolate the fault area based on the target island partitioning scheme to minimize the impact of the fault area on the entire distribution network area. The above technical solution optimizes the initial island partitioning scheme step by step within the global scope of the distribution network through the optimization algorithm to obtain the target island partitioning scheme, and isolates the fault area based on the target island partitioning scheme, so as to minimize the impact of the distribution network fault on the entire distribution network area.

[0019] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in 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 in the following description 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.

[0021] Figure 1 is a flow chart of a distribution network fault isolation method provided according to an embodiment of the present invention;

[0022] Figure 2 is a flow chart of another distribution network fault isolation method provided according to an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of an IEEE 33-node distribution network system as a specific example of another distribution network fault isolation method provided in an embodiment of the present invention;

[0024] Figure 4 is a flowchart of determining an initial island division scheme according to a specific example in another distribution network fault isolation method provided by an embodiment of the present invention;

[0025] Figure 5 is a voltage change diagram before and after reconstruction according to a specific example of another distribution network fault isolation method provided by an embodiment of the present invention;

[0026] Figure 6 is a network loss change diagram before and after reconstruction of a specific example in another distribution network fault isolation method provided by an embodiment of the present invention;

[0027] Figure 7 is a structural block diagram of a distribution network fault isolation device provided according to an embodiment of the present invention;

[0028] Figure 8 It is a structural block diagram of an electronic device for implementing the distribution network fault isolation method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. The situations of "target", "original", etc. are similar and will not be repeated here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] Figure 1 This is a flow chart of a distribution network fault isolation method provided by an embodiment of the present invention. This embodiment is applicable to the case of isolating a fault area in a distribution network. The method can be executed by a distribution network fault isolation device provided by an embodiment of the present invention, and the device can be implemented by software and / or hardware. The device can be integrated on an electronic device, and the electronic device can be various user terminals or servers.

[0032] See also Figure 1 The method of the embodiment of the present invention specifically includes the following steps:

[0033] S110. For the distribution network to be isolated from faults, an initial island division scheme is determined based on the network structure of the distribution network and the fault area in the distribution network.

[0034] The distribution network to be isolated for faults can be understood as a distribution network where the fault area where the fault is located is to be isolated due to a fault in a component in the distribution network, such as a distribution network with a line break fault. The network structure of the power grid can be understood as a network structure that connects the components in the distribution network. The fault area can be understood as the area where the fault part in the distribution network is located, such as the area where the broken line is located when a line break fault occurs.

[0035] The initial island division scheme can be understood as an island division scheme obtained after preliminary island division of the fault area according to the fault area in the power grid network structure. Optionally, the island division can be performed according to the smallest island area where the fault area is located to obtain the initial island division scheme; the island division can also be performed according to the smallest load power of the island where the fault area is located to obtain the initial island division scheme; the island division can also be performed according to the smallest load number of the island where the fault area is located to obtain the initial island division scheme, etc., and no specific restrictions are made here.

[0036] S120, optimizing the initial island partitioning scheme based on a preset cuckoo search algorithm to obtain an optimized island partitioning scheme, and optimizing the optimized island partitioning scheme based on a preset simulated annealing algorithm to obtain a target island partitioning scheme.

[0037] Among them, the cuckoo search algorithm is a nature-inspired algorithm that can be based on the cuckoo's nest parasitism and Levy flight mechanism. It can search for an optimal bird's nest to hatch its own eggs through random walks, which can achieve efficient optimization. The cuckoo search algorithm is used to optimize the initial island partitioning scheme, and a better optimized island partitioning scheme can be explored.

[0038] The simulated annealing algorithm simulates the annealing process in physics, that is, the solution state of the problem is regarded as the state of the physical system, and the objective function value is regarded as the energy of the system. Starting from the initial temperature, a new solution is generated by randomly perturbing the current solution, and whether to accept the new solution is determined according to certain criteria. As the temperature gradually decreases, the system gradually tends to be stable and finally reaches the global optimal solution at low temperature. The simulated annealing algorithm can be used to further optimize the optimized island partitioning scheme to obtain the global optimal solution for the distribution network island partitioning under global conditions, that is, the target island partitioning scheme.

[0039] The initial island partitioning scheme can be optimized based on the preset cuckoo search algorithm, and then the optimized island partitioning scheme can be optimized based on the preset simulated annealing algorithm. Through the two-step optimization, the optimal solution for island partitioning can be found under global conditions, and then the target island partitioning scheme can be obtained.

[0040] S130: Isolate the fault area based on the target island division scheme.

[0041] Among them, after obtaining the target island division scheme, the distribution network can be islanded based on the target island division scheme, thereby achieving isolation of the fault area.

[0042] The technical solution of the embodiment of the present invention is to determine the initial island partitioning scheme based on the network structure of the distribution network and the fault area in the distribution network for the distribution network to be isolated from the fault, so as to complete the preliminary partitioning of the island; optimize the initial island partitioning scheme based on the preset cuckoo search algorithm to obtain the optimized island partitioning scheme, and optimize the optimized island partitioning scheme based on the preset simulated annealing algorithm to obtain the target island partitioning scheme, so as to optimize the initial island partitioning scheme step by step within the global scope of the distribution network and determine the optimal island partitioning scheme; isolate the fault area based on the target island partitioning scheme to minimize the impact of the fault area on the entire distribution network area. The above technical solution optimizes the initial island partitioning scheme step by step within the global scope of the distribution network through the optimization algorithm to obtain the target island partitioning scheme, and isolates the fault area based on the target island partitioning scheme, so as to minimize the impact of the distribution network fault on the entire distribution network area.

[0043] An optional technical solution is provided, which optimizes the initial island partitioning scheme based on a preset cuckoo search algorithm to obtain an optimized island partitioning scheme, including: obtaining the number of algorithm iterations of the preset cuckoo search algorithm; evaluating the island partitioning area for each island partitioning area in the initial island partitioning scheme to obtain an initial fitness value of the island partitioning area; updating the position of the island partitioning area based on the cuckoo search algorithm to obtain an updated island partitioning area, and evaluating the updated fitness value of the updated island partitioning area; updating the initial island partitioning scheme based on all the obtained initial fitness values ​​and all the updated fitness values ​​to obtain an updated island partitioning scheme; using the updated island partitioning scheme as the initial island partitioning scheme, and repeatedly executing the step of evaluating the island partitioning area for each island partitioning area in the initial island partitioning scheme to obtain the initial fitness value of the island partitioning area; when the number of repeated executions reaches the number of algorithm iterations, using the initial island partitioning scheme as the optimized island partitioning scheme.

[0044] Among them, the cuckoo search algorithm is an algorithm that is continuously iterated and optimized. First, the algorithm iteration number of the preset cuckoo search algorithm must be obtained. Then, for each island partition area in the initial island partition scheme, the island partition area is evaluated to obtain the initial fitness value of the island partition area. Optionally, the island partition area can be evaluated according to multiple aspects such as power balance, load priority and network structure during the evaluation to obtain an accurate initial fitness value. Further, based on the cuckoo search algorithm, the position of the island partition area can be updated to obtain an updated island partition area. Optionally, the position of each island partition area can be updated according to strategies such as Levy flight and local random walk to generate an updated island partition area, and then the updated fitness value of the updated island partition area is evaluated. Further, based on comparing all the initial fitness values ​​obtained with all the updated fitness values, the updated island partition area corresponding to the updated fitness value greater than the initial fitness value is replaced with the corresponding initial island partition area to update the initial island partition scheme to obtain an updated island partition scheme. Finally, the updated island partition scheme is used as the initial island partition scheme, and the steps of evaluating each island partition area in the initial island partition scheme to obtain the initial fitness value of the island partition area are repeated. When the number of repeated executions reaches the number of algorithm iterations, the initial island partition scheme is used as the optimized island partition scheme.

[0045] The above technical solution can obtain an optimized island partitioning scheme with a higher fitness value by continuously iterating and optimizing the initial island partitioning scheme through the cuckoo search algorithm.

[0046] Another optional technical solution is to optimize the optimized island partitioning scheme based on a preset simulated annealing algorithm to obtain a target island partitioning scheme, including: obtaining the initial temperature, temperature drop rate and stop condition of the preset simulated annealing algorithm; calculating the initial objective function value of the optimized island partitioning scheme, adjusting the optimized island partitioning scheme, generating an adjusted island partitioning scheme, and calculating the adjusted objective function value of the adjusted island partitioning scheme, wherein the initial objective function value is used to characterize the quality of the optimized island partitioning scheme, and the adjusted objective function value is used to characterize the quality of the adjusted island partitioning scheme; when the adjusted objective function value is greater than the initial objective function value, based on the adjusted island partitioning scheme Update the optimized island partitioning scheme; when the adjusted objective function value is less than or equal to the initial objective function value, based on the updated probability and the adjusted island partitioning scheme, update the optimized island partitioning scheme, reduce the initial temperature based on the temperature drop rate to obtain an intermediate temperature, wherein the updated probability is associated with the intermediate temperature, and the difference between the adjusted objective function value and the initial objective function value; repeat the steps of calculating the initial objective function value of the optimized island partitioning scheme, adjusting the optimized island partitioning scheme, generating an adjusted island partitioning scheme, and calculating the adjusted objective function value of the adjusted island partitioning scheme, and when the intermediate temperature reaches the stopping condition, use the optimized island partitioning scheme as the target island partitioning scheme.

[0047] Among them, after obtaining the optimized island partitioning scheme, the optimized island partitioning scheme can be further optimized by using the simulated annealing algorithm. First, the initial temperature, temperature drop rate and stop condition of the preset simulated annealing algorithm are obtained to determine the end condition of the simulated annealing algorithm. Then, the initial objective function value used to characterize the quality of the optimized island partitioning scheme is calculated, and the optimized island partitioning scheme is adjusted to generate an adjusted island partitioning scheme, and the adjusted objective function value characterizing the quality of the adjusted island partitioning scheme is calculated. Further, the initial objective function value and the adjusted objective function value are compared. When the adjusted objective function value is greater than the initial objective function value, the optimized island partitioning scheme is updated based on the adjusted island partitioning scheme; when the adjusted objective function value is less than or equal to the initial objective function value, the optimized island partitioning scheme is updated with the adjusted island partitioning scheme with a certain update probability. Optionally, the update probability can be calculated by the intermediate temperature and the difference between the adjusted objective function value and the initial objective function value, and the intermediate temperature is obtained by reducing the initial temperature based on the temperature drop rate. The steps of calculating the initial objective function value of the optimized island partitioning scheme, adjusting the optimized island partitioning scheme, generating an adjusted island partitioning scheme, and calculating the adjusted objective function value of the adjusted island partitioning scheme are continuously repeated until the intermediate temperature drops to the stopping condition, and the optimized island partitioning scheme is used as the target island partitioning scheme.

[0048] The above technical solution can determine the optimal target island partitioning scheme by continuously adjusting and updating the optimized island partitioning scheme through a simulated annealing algorithm.

[0049] Figure 2 It is a flow chart of another distribution network fault isolation method provided in an embodiment of the present invention. This embodiment is optimized based on the above-mentioned technical solutions. In this embodiment, optionally, based on the grid network structure of the distribution network and the fault area in the distribution network, an initial island division scheme is determined, including: based on the grid network structure of the distribution network and the fault area of ​​the distribution network, obtaining a target network structure including the fault area; based on the target network structure and the importance level of each load in the distribution network, determining the initial island division scheme. Among them, the explanations of the terms that are the same or corresponding to the above-mentioned embodiments are not repeated here.

[0050] See also Figure 2 The method of this embodiment may specifically include the following steps:

[0051] S210. For the distribution network to be isolated for fault, based on the power grid network structure of the distribution network and the fault area of ​​the distribution network, obtain a target network structure including the fault area.

[0052] Among them, the target network structure can be understood as the network structure including the fault area obtained after simplifying the network structure of the power grid. Optionally, the power grid network structure can be simplified based on the switch branch exchange method. Specifically, the load in the distribution network can be represented as a constant current using the result of the flow calculation. When simplifying the network structure, only one connecting switch is closed at a time to form a ring network in the distribution network, and then a section switch in the ring network is selected and opened. In order to reduce the amount of calculation, it is believed that only when there is a significant voltage difference between the two ends of the connecting switch and the load is transferred from the low voltage side to the high voltage side, can the network loss be reduced. Suppose there is a connecting switch S on the line between bus m and bus n. m–n , the approximate change formula of network loss during load transfer is as follows:

[0053]

[0054] Where D is the busbar set of the transferred load; I i is the current of busbar i before load transfer; R loop is the sum of the resistances of all lines in the loop; E m and E n The bus voltage at both ends of the contact switch is connected respectively.

[0055] When ΔP is less than zero, it means the network loss is reduced, otherwise it means the network loss is increased. m <E n, and the load is transferred from the n side to the m side, the network loss may be reduced. If the network loss is reduced, the branch is exchanged, otherwise it is not exchanged, thereby simplifying the power grid network structure and obtaining the target network structure.

[0056] S220: Determine an initial island partitioning scheme based on the target network structure and the importance level of each load in the distribution network.

[0057] Among them, the target network structure includes multiple loads. When performing island division, the initial island division plan can be determined based on the importance level of each load. For example, loads with higher importance levels can be divided into islands as much as possible to restore loads with higher importance levels first to reduce failure losses.

[0058] S230, optimizing the initial island partitioning scheme based on a preset cuckoo search algorithm to obtain an optimized island partitioning scheme, and optimizing the optimized island partitioning scheme based on a preset simulated annealing algorithm to obtain a target island partitioning scheme.

[0059] S240: Isolate the fault area based on the target island division scheme.

[0060] The technical solution of the embodiment of the present invention simplifies the power grid network structure to obtain the target network structure, and divides the target network structure into islands based on the importance level of the load, so as to quickly restore the loads with higher importance levels and obtain a more reasonable initial island division scheme.

[0061] An optional technical solution determines an initial island partitioning scheme based on a target network structure and the importance level of each load in a distribution network, including: for each load in the distribution network, based on the importance level of the load, determining the priority coefficient of the node where the load is located; constructing a key recovery set and a load shedding sequence set based on all the priority coefficients obtained; for each root node connected to the power system in the target network structure, determining the output value corresponding to the root node; and obtaining an initial island partitioning scheme based on multiple root nodes, the output values ​​corresponding to the multiple root nodes, the key recovery set and the load shedding sequence set.

[0062] Among them, the priority coefficient can be understood as a coefficient that characterizes the priority recovery order of the node after evaluating the node where the load is located based on the importance level of the load. According to the size of the priority coefficient corresponding to each node, the nodes in the target network structure can be classified, and the key recovery set can be constructed based on the nodes with higher priority coefficients, and the load shedding order set can be constructed based on the nodes with lower priority coefficients.

[0063] For each root node connected to the power system in the target network structure, the output value corresponding to the root node is calculated, and then the target network structure is divided into islands based on multiple root nodes, the output values ​​corresponding to multiple root nodes, the key recovery set and the load shedding sequence set, and multiple island areas are obtained. Optionally, for each root node, the island range can be determined with the root node as the center and the output value corresponding to the root node as the radius, and the island range contains as many nodes in the key recovery set as possible, and the nodes in the load shedding set are removed according to actual needs to obtain an island area. Finally, the initial island division scheme can be determined based on the multiple island areas obtained.

[0064] The technical solution of the embodiment of the present invention determines the initial island partitioning scheme according to the specific situation of the root node and the priority coefficient of the node, and can obtain a more reasonable initial island partitioning scheme.

[0065] On this basis, optionally, based on multiple root nodes, the output values ​​corresponding to the multiple root nodes, the key recovery sets and the load shedding sequence sets, an initial island division scheme is obtained, including: for each root node, an island area is obtained with the root node as the center and the output value corresponding to the root node as the search radius; for each unrecovered node in the key recovery set that is not in the multiple island areas, the unrecovered node is connected to the island area closest to the unrecovered node in the multiple island areas to obtain a first adjusted island area; based on the load shedding sequence set, the first adjusted island area is adjusted to obtain a second adjusted island area; based on the obtained multiple second adjusted island areas, an initial island division scheme is obtained.

[0066] Among them, when dividing the island area, for each root node, the root node can be used as the center and the output value corresponding to the root node can be used as the search radius to obtain a preliminary island area. Optionally, the breadth-first search method (BFS) can be used to determine the island area. At the same time, if there is an intersection between two island areas, they can be merged into one island area. Since it is difficult to include all the nodes in the key recovery set in the island area, for each unrecovered node in the key recovery set that is not in multiple island areas, the unrecovered node can be connected to the island area closest to the unrecovered node in multiple island areas to obtain the first adjusted island area. Optionally, in the process of connecting the unrecovered node, a combined depth-first search method (DFS) can be used to connect the unrecovered node to the closest island area. After connecting nodes with higher priority coefficients to the island area, the power of the island will exceed the rated power. Therefore, it is necessary to adjust the first adjustment island area based on the load shedding sequence set so that the power in the island area is less than the rated power, thereby obtaining the second adjustment island area, and based on the obtained multiple second adjustment island areas, obtain the initial island division plan.

[0067] The above technical solution can give priority to restoring more important nodes after island division, thereby minimizing failure losses as much as possible.

[0068] On this basis, optionally, based on the load shedding sequence set, the first adjustment island area is adjusted to obtain a second adjustment island area, including: based on the load shedding sequence set, cutting off the node with the smallest priority coefficient in the first adjustment island area to obtain the second adjustment island area; when the power in the island in the second adjustment island area is greater than a preset power threshold, updating the first adjustment island area based on the second adjustment island area, and repeating the step of cutting off the node with the smallest priority coefficient in the first adjustment island area based on the load shedding sequence set to obtain the second adjustment island area.

[0069] Among them, when adjusting the island area based on the load shedding sequence set, it is necessary to restore as many loads in the load shedding sequence set as possible, that is, the load shedding during the fault period is the minimum, that is:

[0070]

[0071] Where: i.t represents the priority coefficient of the node where the load of node i is located in time period t; P Li.t represents the load active power of node i during period t; y i.t represents the state variable of node i accessing the island during period t, y i.t =1 means load removal, y i.t=0 indicates that the load is not cut off; L indicates the load cutting sequence set.

[0072] Therefore, based on the load shedding sequence set, the node with the smallest priority coefficient in the first adjustment island area can be cut off to obtain the second adjustment island area, and the power in the island at this time can be calculated. When the power in the island in the second adjustment island area is greater than the preset power threshold, it means that load shedding is still required. At this time, the first adjustment island area is updated based on the second adjustment island area, and the step of cutting off the node with the smallest priority coefficient in the first adjustment island area based on the load shedding sequence set to obtain the second adjustment island area is repeated, so that the second island adjustment area can be obtained with the least load cut.

[0073] The above technical solution can ensure that when the initial island sub-scheme is divided, as many loads of general importance as possible are restored while ensuring that important loads are restored first.

[0074] Another optional technical solution, based on the grid network structure of the distribution network and the fault area of ​​the distribution network, before obtaining the target network structure including the fault area, includes: determining whether a fault occurs in the distribution network based on a preset negative sequence voltage mutation amount; if so, determining the grid network structure and the fault area.

[0075] Among them, when a fault occurs in the distribution network, negative sequence voltage will appear. At the same time, since negative sequence voltage will also exist due to load imbalance when the system is operating normally, it is possible to determine whether a fault occurs in the distribution network based on the preset negative sequence voltage mutation amount. The specific judgment formula is as follows

[0076]

[0077] in: is the negative sequence voltage after the distribution network fault; It is the negative sequence voltage generated by load imbalance during normal operation; ΔU n is the amplitude of the negative sequence voltage mutation; U nset It is the setting value of negative sequence voltage.

[0078] Optionally, since the start-up criterion has taken into account the influence of factors such as load imbalance during normal operation, in principle, the start-up can be performed when the amplitude of the negative sequence voltage mutation is very small, so the preset negative sequence voltage mutation amount can be set lower, such as 5% of the rated voltage of the system. And when it is determined that a fault occurs in the distribution network, the network structure of the power grid and the fault area are further determined.

[0079] The above technical solution can accurately determine whether a fault occurs in the distribution network.

[0080] In order to better understand the above-mentioned model training process as a whole, the following is an exemplary description with reference to a specific example. In this example, the distribution network is an IEEE 33-node distribution network system. The schematic diagram of the IEEE 33-node distribution network system is as follows: Figure 3 As shown, the specific steps are as follows:

[0081] First, based on the preset negative sequence voltage mutation amount, determine whether a fault occurs in the IEEE 33-node distribution network system. In the event that a fault occurs in the IEEE 33-node distribution network system, determine the power grid network structure and fault area of ​​the IEEE 33-node distribution network system.

[0082] 2. Simplify the power grid network structure based on the switch branch exchange method to obtain the target network structure.

[0083] 3. Divide the target network structure into islands and obtain an initial island division plan.

[0084] The specific flow chart is as follows Figure 4 As shown, the specific process is as follows:

[0085] 1) Input distribution network data (i.e. target network structure), fault location and fault time.

[0086] 2) Determine the system output (i.e. output value) at the time of failure and the priority coefficient λ of load recovery at each node t , arrange the nodes from small to large to get the load shedding sequence set L load (i.e. load shedding sequence set), and t Large nodes are placed in the key recovery set M load .

[0087] 3) Take the node where the system is located as the root node and its output value as the search radius, and use the BFS method to determine the island range (i.e., island area). If an intersection occurs, the islands are combined.

[0088] 4) Use DFS method to convert M load The unrecovered nodes in the cluster are connected to the nearest island (i.e., the island area).

[0089] 5) Determine the power constraint within the island. If it is not satisfied, go to step 6), otherwise go to step 7).

[0090] 6) Mark the end node of the island as the shelvable load set C load , according to L load Sequential search in cutoff λ t The smallest node, update island range and C load And go to step 5).

[0091] 7) Mark all unrestored loads and removed load nodes to obtain the final island partitioning solution (i.e., the initial island partitioning solution).

[0092] 4. Optimize the initial island partitioning scheme based on the preset cuckoo search algorithm to obtain the optimized island partitioning scheme.

[0093] 5. Optimize the optimized island partitioning scheme based on the preset simulated annealing algorithm to obtain the target island partitioning scheme.

[0094] After the IEEE 33-node distribution network system is islanded based on the target islanding partitioning scheme, the comparison of the results before and after the reconstruction of the IEEE 33-node distribution network system is shown in the following table:

[0095] Table 1 Comparison of distribution network optimization results

[0096]

[0097] The voltage change diagram of the IEEE 33-node distribution network system before and after reconstruction is shown in the figure Figure 5 As shown in Figure 2, the network loss of the IEEE 33-node distribution network system before and after reconstruction varies with the number of iterations of the simulated annealing algorithm. Figure 6 shown.

[0098] In this specific example, through the optimization algorithm, the initial island division scheme is optimized step by step in the global scope of the distribution network to obtain the target island division scheme, and the fault area is isolated based on the target island division scheme, which can minimize the impact of the distribution network fault on the entire distribution network area.

[0099] Figure 7 This is a structural block diagram of a distribution network fault isolation device provided in an embodiment of the present invention, and the device is used to execute the distribution network fault isolation method provided in any of the above embodiments. The device and the distribution network fault isolation method in the above embodiments belong to the same inventive concept, and the details not described in detail in the embodiment of the distribution network fault isolation device can refer to the embodiment of the distribution network fault isolation method. Figure 7 The device may specifically include: an initial island partitioning scheme determining module 310, an initial island partitioning scheme obtaining module 320 and a fault area isolation module 330.

[0100] An initial island partitioning scheme determining module 310 is used to determine an initial island partitioning scheme for a distribution network to be subjected to fault isolation based on the network structure of the distribution network and the fault area in the distribution network;

[0101] An initial island partitioning scheme obtaining module 320 is used to optimize the initial island partitioning scheme based on a preset cuckoo search algorithm to obtain an optimized island partitioning scheme, and to optimize the optimized island partitioning scheme based on a preset simulated annealing algorithm to obtain a target island partitioning scheme;

[0102] The fault area isolation module 330 is used to isolate the fault area based on the target island division scheme.

[0103] Optionally, the initial island division scheme determination module 310 includes:

[0104] A target network structure acquisition submodule is used to acquire a target network structure including a fault area based on the power grid network structure of the distribution network and the fault area of ​​the distribution network;

[0105] The initial island partitioning scheme determination submodule is used to determine the initial island partitioning scheme based on the target network structure and the importance level of each load in the distribution network.

[0106] On this basis, an optional initial island division scheme determination submodule includes:

[0107] A priority coefficient determination unit, for determining, for each load in the distribution network, a priority coefficient of a node where the load is located based on an importance level of the load;

[0108] A load shedding sequence set construction unit, used for constructing a key restoration set and a load shedding sequence set based on all obtained priority coefficients;

[0109] An output value determination unit, used for determining an output value corresponding to each root node connected to the power system in the target network structure;

[0110] The initial island partitioning scheme obtaining unit is used to obtain the initial island partitioning scheme based on a plurality of root nodes, output values ​​respectively corresponding to the plurality of root nodes, a key restoration set and a load shedding sequence set.

[0111] On this basis, an optional, initial island partitioning scheme is used to obtain units, including:

[0112] The island region obtaining unit is used for obtaining the island region for each root node by taking the root node as the center and the output value corresponding to the root node as the search radius;

[0113] The first adjustment island region obtaining subunit is used for connecting the unrecovered node to the island region closest to the unrecovered node among the multiple island regions for each unrecovered node in the key recovery set that is not in the multiple island regions, to obtain a first adjustment island region;

[0114] A second adjustment island region obtaining subunit is used to adjust the first adjustment island region based on the load shedding sequence set to obtain a second adjustment island region;

[0115] The initial island division scheme obtaining subunit is used to obtain an initial island division scheme based on the obtained multiple second adjusted island regions.

[0116] On this basis, optionally, the second adjustment of the island region to obtain a subunit includes:

[0117] A node removal subunit is used to remove the node with the smallest priority coefficient in the first adjustment island area based on the load shedding sequence set to obtain a second adjustment island area;

[0118] The first adjustment island area update subunit is used to update the first adjustment island area based on the second adjustment island area when the power in the island in the second adjustment island area is greater than a preset power threshold, and repeatedly execute the step of cutting off the node with the smallest priority coefficient in the first adjustment island area based on the load cutting sequence set to obtain the second adjustment island area.

[0119] Alternatively, before obtaining the target network structure including the fault area based on the power distribution network structure and the fault area of ​​the distribution network, the method further includes:

[0120] A fault judgment module is used to determine whether a fault occurs in the distribution network based on a preset negative sequence voltage mutation amount;

[0121] The fault area determination module is used to determine the power grid network structure and the fault area in the case of yes.

[0122] Alternatively, the initial island partitioning scheme obtaining module 320 includes:

[0123] An algorithm iteration number acquisition submodule is used to acquire the algorithm iteration number of a preset cuckoo search algorithm;

[0124] The initial fitness value obtaining submodule is used to evaluate each island partition area in the initial island partition scheme to obtain the initial fitness value of the island partition area;

[0125] An update fitness value evaluation submodule is used to update the position of the isolated island partition area based on the cuckoo search algorithm, obtain the updated isolated island partition area, and evaluate the update fitness value of the updated isolated island partition area;

[0126] The submodule for updating the island partitioning scheme is used to update the initial island partitioning scheme based on all the initial fitness values ​​and all the updated fitness values ​​to obtain an updated island partitioning scheme;

[0127] The first repetitive execution submodule is used to use the updated island partitioning scheme as the initial island partitioning scheme, and repeatedly execute the step of evaluating each island partitioning area in the initial island partitioning scheme to obtain an initial fitness value of the island partitioning area;

[0128] The optimized island partitioning scheme determination submodule is used to use the initial island partitioning scheme as the optimized island partitioning scheme when the number of repeated executions reaches the number of algorithm iterations.

[0129] In another alternative, the initial island partitioning scheme obtaining module 320 further includes:

[0130] The stop condition acquisition submodule is used to obtain the initial temperature, temperature drop rate and stop condition of the preset simulated annealing algorithm;

[0131] The adjustment objective function value calculation submodule is used to calculate the initial objective function value of the optimized island partitioning scheme, adjust the optimized island partitioning scheme, generate an adjusted island partitioning scheme, and calculate the adjusted objective function value of the adjusted island partitioning scheme, wherein the initial objective function value is used to characterize the quality of the optimized island partitioning scheme, and the adjusted objective function value is used to characterize the quality of the adjusted island partitioning scheme;

[0132] The optimized island partitioning scheme updating submodule is used to update the optimized island partitioning scheme based on the adjusted island partitioning scheme when the adjusted objective function value is greater than the initial objective function value;

[0133] The intermediate temperature obtaining submodule is used for updating and optimizing the island partitioning scheme based on the update probability and the adjustment island partitioning scheme when the adjustment objective function value is less than or equal to the initial objective function value, and reducing the initial temperature based on the temperature drop rate to obtain the intermediate temperature, wherein the update probability is associated with the intermediate temperature and the difference between the adjustment objective function value and the initial objective function value;

[0134] The second repeated execution submodule is used to repeatedly execute the steps of calculating the initial objective function value of the optimized island partitioning scheme, adjusting the optimized island partitioning scheme, generating an adjusted island partitioning scheme, and calculating the adjusted objective function value of the adjusted island partitioning scheme. When the intermediate temperature reaches the stopping condition, the optimized island partitioning scheme is used as the target island partitioning scheme.

[0135] The distribution network fault isolation device of the embodiment of the present invention determines the initial island partitioning scheme for the distribution network to be isolated based on the network structure of the distribution network and the fault area in the distribution network through the initial island partitioning scheme determination module to complete the preliminary division of the island; optimizes the initial island partitioning scheme based on the preset cuckoo search algorithm to obtain the optimized island partitioning scheme, and optimizes the optimized island partitioning scheme based on the preset simulated annealing algorithm to obtain the target island partitioning scheme, so as to optimize the initial island partitioning scheme step by step within the global scope of the distribution network and determine the optimal island partitioning scheme; isolates the fault area based on the target island partitioning scheme through the fault area isolation module to minimize the impact of the fault area on the entire distribution network area. The above device optimizes the initial island partitioning scheme step by step within the global scope of the distribution network through the optimization algorithm to obtain the target island partitioning scheme, and isolates the fault area based on the target island partitioning scheme, which can minimize the impact of the distribution network fault on the entire distribution network area.

[0136] The distribution network fault isolation device provided in the embodiment of the present invention can execute the distribution network fault isolation method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0137] It is worth noting that in the above-mentioned embodiment of the distribution network fault isolation device, the various units and modules included are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be achieved; in addition, the specific names of the functional units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0138] Figure 8 A schematic diagram of the structure of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components, their connections and relationships, and their functions herein are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0139] like Figure 8The electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0140] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0141] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as a distribution network fault isolation method.

[0142] In some embodiments, the distribution network fault isolation method may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the distribution network fault isolation method described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to execute the distribution network fault isolation method in any other appropriate manner (e.g., by means of firmware).

[0143] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0144] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0145] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0146] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0147] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0148] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0149] It should be understood that the above various forms of processes can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0150] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A distribution network fault isolation method, characterized in that: include: For a distribution network to be isolated from a fault, an initial island division scheme is determined based on a network structure of the distribution network and a fault area in the distribution network; The initial island partitioning scheme is optimized based on a preset cuckoo search algorithm to obtain an optimized island partitioning scheme, and the optimized island partitioning scheme is optimized based on a preset simulated annealing algorithm to obtain a target island partitioning scheme; The fault area is isolated based on the target island partitioning scheme.

2. The method according to claim 1, characterized in that The determining of an initial island partitioning scheme based on the power grid network structure of the distribution network and the fault area in the distribution network includes: Based on the power grid network structure of the distribution network and the fault area of ​​the distribution network, acquiring a target network structure including the fault area; An initial island partitioning scheme is determined based on the target network structure and the importance level of each load in the distribution network.

3. The method according to claim 2, characterized in that The determining of an initial island partitioning scheme based on the target network structure and the importance level of each load in the distribution network comprises: For each load in the distribution network, based on the importance level of the load, determining a priority coefficient of a node where the load is located; Constructing a key restoration set and a load shedding sequence set based on all the priority coefficients obtained; For each root node connected to the power system in the target network structure, determining an output value corresponding to the root node; An initial island partitioning scheme is obtained based on the plurality of root nodes, the output values ​​respectively corresponding to the plurality of root nodes, the key restoration set and the load shedding sequence set.

4. The method according to claim 3, characterized in that The initial island partitioning scheme is obtained based on the plurality of root nodes, the output values ​​respectively corresponding to the plurality of root nodes, the key restoration set and the load shedding sequence set, including: For each of the root nodes, taking the root node as the center and the output value corresponding to the root node as the search radius, an island area is obtained; For each unrecovered node in the key recovery set that is not in the plurality of isolated island areas, the unrecovered node is connected to the isolated island area closest to the unrecovered node among the plurality of isolated island areas to obtain a first adjusted isolated island area; Based on the load shedding sequence set, adjusting the first adjustment island area to obtain a second adjustment island area; Based on the obtained multiple second adjusted island regions, an initial island division scheme is obtained.

5. The method according to claim 4, characterized in that The adjusting the first adjustment island region based on the load shedding sequence set to obtain a second adjustment island region includes: Based on the load shedding sequence set, removing the node with the smallest priority coefficient in the first adjustment island region to obtain a second adjustment island region; When the power within the island in the second adjustment island area is greater than a preset power threshold, the first adjustment island area is updated based on the second adjustment island area, and the step of removing the node with the smallest priority coefficient in the first adjustment island area based on the load shedding sequence set to obtain the second adjustment island area is repeated.

6. The method according to claim 2, characterized in that Before acquiring the target network structure including the fault area based on the power distribution network structure and the fault area of ​​the distribution network, the method includes: Determining whether a fault occurs in the distribution network based on a preset negative sequence voltage mutation amount; If yes, the power grid network structure and the fault area are determined.

7. The method according to claim 1, characterized in that The initial island partitioning scheme is optimized based on a preset cuckoo search algorithm to obtain an optimized island partitioning scheme, including: Get the number of algorithm iterations of the preset cuckoo search algorithm; For each isolated island partition area in the initial isolated island partition scheme, the isolated island partition area is evaluated to obtain an initial fitness value of the isolated island partition area; Based on the cuckoo search algorithm, the position of the isolated island partition area is updated to obtain an updated isolated island partition area, and the updated fitness value of the updated isolated island partition area is evaluated; Based on all the obtained initial fitness values ​​and all the obtained updated fitness values, updating the initial island partitioning scheme to obtain an updated island partitioning scheme; Using the updated island partitioning scheme as the initial island partitioning scheme, repeatedly executing the step of evaluating each island partitioning area in the initial island partitioning scheme to obtain an initial fitness value of the island partitioning area; When the number of repeated executions reaches the number of algorithm iterations, the initial island partitioning scheme is used as the optimized island partitioning scheme.

8. The method according to claim 1, characterized in that: The optimized island partitioning scheme is optimized based on a preset simulated annealing algorithm to obtain a target island partitioning scheme, including: Obtain the preset initial temperature, temperature drop rate and stop condition of the simulated annealing algorithm; Calculating an initial objective function value of the optimized island partitioning scheme, adjusting the optimized island partitioning scheme, generating an adjusted island partitioning scheme, and calculating an adjusted objective function value of the adjusted island partitioning scheme, wherein the initial objective function value is used to characterize the quality of the optimized island partitioning scheme, and the adjusted objective function value is used to characterize the quality of the adjusted island partitioning scheme; When the adjusted objective function value is greater than the initial objective function value, updating the optimized island partitioning scheme based on the adjusted island partitioning scheme; In the case where the adjusted objective function value is less than or equal to the initial objective function value, based on the update probability and the adjusted island division scheme, the optimized island division scheme is updated, and the initial temperature is reduced based on the temperature drop rate to obtain an intermediate temperature, wherein the update probability is associated with the intermediate temperature and the difference between the adjusted objective function value and the initial objective function value; Repeat the steps of calculating the initial objective function value of the optimized island partitioning scheme, adjusting the optimized island partitioning scheme, generating an adjusted island partitioning scheme, and calculating the adjusted objective function value of the adjusted island partitioning scheme. When the intermediate temperature reaches the stop condition, use the optimized island partitioning scheme as the target island partitioning scheme.

9. An electronic device, characterized in that: include: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor performs the distribution network fault isolation method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the distribution network fault isolation method as described in any one of claims 1-8 when executed.

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