Regional network attack-oriented power distribution network key equipment identification method and system

Abstract

The invention discloses a regional network attack-oriented power distribution network key equipment identification method and system, and relates to the technical field of intelligent power grids, and the method comprises the steps: identifying a power distribution network wiring mode based on a power distribution network topology model, and obtaining a power supply path of a regional power distribution network user; based on the power supply path, obtaining an optimal network attack reachable distribution line switch to form a data set, forming a first scheme with the minimum output additional loss, and finding a second scheme with the minimum number of switches according to an iterative optimization algorithm; and identifying the key equipment of the distribution network according to the first scheme or the second scheme. According to the invention, through the iterative optimization algorithm, the action of the power distribution line switch is decided to simulate a power failure scheme that an attacker carries out network attacks on the regional power distribution network, so that effective protection measures can be formulated in advance, and the security defense capability of the power distribution network is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of smart grids, and in particular, to a method and system for identifying key equipment of a distribution network facing regional network attacks. Background Art

[0002] With the rapid development of smart grids, the network security issue of distribution networks has attracted increasing attention. As the end link of the power system, the distribution network connects a large number of users and plays an important role in power supply. However, while the in-depth application of information technology and communication technology improves the intelligence level of the distribution network, it also makes it face higher-risk network attacks. The distribution network has significant characteristics such as multiple voltage levels, complex structures, diverse equipment types, and relatively weak security environments, which reduce the difficulty for attackers to carry out network attacks. In the power system, network attacks on the distribution network generally target its vulnerable or key equipment, including substations, switchgear, distribution automation equipment, and remote terminals. Once the key equipment is attacked by a network, it may cause large-scale power outages, serious economic losses, and even pose a threat to social stability. Therefore, accurately identifying the key equipment in the distribution network and effectively protecting it in advance are the keys to resisting network attacks and reducing the risks of the distribution system. This not only helps to improve the security and reliability of the distribution network but also has important significance for ensuring the stable operation of the power system.

[0003] In modern power systems, due to the lack of sufficient physical or network isolation for some distribution network equipment, attackers may take advantage of this vulnerability to obtain the network information of the equipment and carry out remote attacks. For example, when the communication protocols used in the distribution network do not adopt effective encryption and authentication measures, attackers can identify and control the equipment through means such as man-in-the-middle attacks and replay attacks. These security risks significantly increase the risk of the distribution network being attacked by a network, posing a potential threat to the stability and reliability of the power system. Therefore, taking effective isolation protection measures for key equipment in advance and optimizing the encryption and authentication mechanisms of communication protocols are the key means to improve the network security level of the distribution network.

[0004] The existing technologies mainly focus on the identification of key equipment in the power system, providing a certain theoretical basis for formulating protection strategies for the power system to resist network attacks. However, most current studies mainly focus on the identification of key equipment in the entire distribution network under network attacks, and there is less research on the identification of key equipment in the distribution network facing regional network attacks. With the continuous breakthrough and rapid development of network attack technologies, the probability of accurately attacking a specific local area of the distribution network and causing its incapacity has increased significantly. Therefore, it is urgent to carry out research on methods for identifying key equipment facing local area network attacks to effectively improve the security protection ability and overall reliability of the distribution network. Summary of the Invention

[0005] To solve the above problems, the object of the present invention is to provide a key equipment identification technology for distribution networks facing regional network attacks, aiming to improve the security defense ability of distribution networks.

[0006] To achieve the above technical object, the present application provides a key equipment identification method for distribution networks facing regional network attacks, including the following steps:

[0007] Based on the distribution network topology model, identify the distribution network wiring mode and obtain the power supply path of regional distribution network users;

[0008] Based on the power supply path, obtain a data set of distribution line switches that can be reached by the optimal network attack, form a first solution with the minimum additional loss, and find a second solution with the fewest number of switches according to the iterative optimization algorithm;

[0009] Identify the key equipment of the distribution network according to the first solution or the second solution.

[0010] Preferably, in the process of obtaining the distribution network topology model, the distribution network is topologically modeled based on the research of complex network theory.

[0011] Preferably, when obtaining the power supply path of regional distribution network users, all associated feeders in the target area are modeled as an undirected graph; all key users in the target area are used as the initial nodes, and the circuit breakers of all distribution transformers on the feeders where the users are located and at the upper level of the tie feeders are the targets; according to different network structures and tie switch types, the minimum path algorithm is used to search from the initial nodes to the targets respectively, and all possible minimum paths for supplying power to important users in the target area are obtained and a minimum path table is formed as the power supply path of regional distribution network users.

[0012] Preferably, when obtaining the first solution, check whether there is a network attack target switch upstream of other network attack target switches according to the upstream and downstream relationship. If so, delete all network attack target switches downstream of this switch, and then check whether there are other switches that can replace the existing switch combination for switch simplification to form the first solution.

[0013] Preferably, when using the iterative optimization algorithm, the distribution line switches that can be reached by the network attack on the power supply path are sorted according to importance and then the initial solution is screened. Through the iterative optimization algorithm, specific steps are repeated to gradually optimize the quality of the initial solution; in each iteration, a potentially better solution is generated using the information of the current solution until the stop condition is met.

[0014] Preferably, when obtaining the second solution, the switches obtained in the solution with the minimum additional loss are used as target switches for importance ranking; the optimal distribution line switches reachable by network attack are selected according to the importance ranking and the position information of the switches on the feeder; the power outage situation in the target area is evaluated to determine whether all power supply paths in the target area have been cut off. If the expected goal is achieved, all current target switches are provided to the user as output. If the expected goal is not achieved, the process returns and continues to loop to obtain the second solution with the minimum number of switches.

[0015] Preferably, when identifying key distribution network devices, according to the additional loss caused by the second solution; compared with the first solution, if the additional loss caused is more than twice the target, the solution with the minimum additional loss is used as the optimal solution. Otherwise, the solution with the minimum number of attacked switches is used as the output, and based on the output result, key distribution network devices are identified.

[0016] The present invention discloses a key distribution network device identification system for regional network attacks, including:

[0017] A path planning module for identifying the wiring mode of the distribution network based on the distribution network topology model and obtaining the power supply paths of regional distribution network users;

[0018] A solution acquisition module for forming a data set of the optimal distribution line switches reachable by network attack based on the power supply paths, forming the first solution with the minimum output additional loss, and finding the second solution with the minimum number of switches according to the iterative optimization algorithm;

[0019] An identification module for identifying key distribution network devices according to the first solution or the second solution.

[0020] The present invention discloses the following technical effects:

[0021] Through the iterative optimization algorithm, the present invention decides the actions of distribution line switches to simulate the power outage plan of an attacker's network attack on the regional distribution network, and thus effective protection measures can be formulated in advance to improve the security defense ability of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a node system diagram of the present invention;

[0024] Figure 2 is the radial distribution network topology diagram described in the present invention;

[0025] Figure 3 is the radial-connected distribution network topology diagram described in the present invention;

[0026] Figure 4 is the normally open loop type distribution network topology diagram described in the present invention;

[0027] Figure 5 is the normally closed loop type distribution network topology diagram described in the present invention;

[0028] Figure 6 is the schematic diagram of the ATS automatic transfer switch described in the present invention;

[0029] Figure 7 is the schematic diagram of the method flow described in the present invention. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents the selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application.

[0031] As Figure 1-7 shown, the present invention provides a key equipment identification technology for distribution networks facing regional network attacks. Based on the topological structure of the distribution network in a specific area, this technology first determines the key targets in the area, and uses the improved minimum path method to search and determine all power supply paths to reach the target users, and then identifies the key distribution equipment that may be affected by network attacks on the paths, such as line switches. To make the attack more concealed, the attacker usually deliberately controls the affected range outside the key targets to avoid causing large-scale power outages. Therefore, this technology uses an iterative optimization algorithm to decide the actions of the distribution line switches to simulate the power outage plan of the attacker's network attack on the regional distribution network; the process includes the following:

[0032] 1. Data preprocessing:

[0033] 1) Use the data provided by the user to separately extract the busbars and form a new table to improve the calculation speed;

[0034] 2) Combine the CID and OID to form a unique representation of the device (CID represents the device type, e.g., 101 for busbar, 114 for switch; OID is the number, but the OID is not unique. Only CID + OID can form a unique data representation);

[0035] 3) Since ATSs appear in pairs and the states of the two switches are generally one open and one closed and will not close simultaneously, for such switches, the open / closed state in the data table is written as (0, 1); The normally open switch is a special type of switch that controls transfer power supply. Through it, the transfer power supply for special users can be achieved. It is generally in the open state and is made to be in the normally closed state in the data table, written as 1;

[0036] 4) Take all important target users within the target area selected by the user as the input.

[0037] 2. Search by the minimum path method within the selected area of the distribution network:

[0038] After the data processing is completed, form a path table for all important users within the target area according to the minimum path algorithm. The specific steps are as follows:

[0039] 1) Determine the starting node and the target node, where the target node is the circuit breaker at the head end of all possible feeders;

[0040] 2) Initialize the algorithm, set the distance of the starting node to 0, set the distances of all other nodes to infinity (or a relatively large value), and mark the starting node as visited;

[0041] 3) For all nodes adjacent to the starting node, update their distance values (the distance to the starting node);

[0042] 4) Among all unvisited nodes, select the node with the minimum distance as the next node to be visited and mark it as visited;

[0043] 5) For all unvisited nodes adjacent to this node, update their distance values (the distance to the starting node);

[0044] 6) Repeat steps four and five until the target node is marked as visited or all nodes have been visited;

[0045] 7) For the distribution network structure with multiple transfer power supply paths, set the states of the paired ATSs to (0, 1) and (1, 0) respectively, and set the open switches to the closed state to perform the minimum path method search;

[0046] 8) Since a single feeder forms an independent loop and possible power supply paths that are not the shortest paths will be ignored, set the switches on each path to 0 respectively and search for the shortest path again. Loop this step until no new path can be found;

[0047] 9) Determine whether all important users in the target area have been traversed. If not, use the untraversed important users as the initial nodes and return to the first step to recalculate;

[0048] 10) Obtain the minimum power supply paths of all reachable key target users in the selected area and form a minimum path set as the output.

[0049] 3. Output the scheme with the minimum additional loss (the first scheme):

[0050] Based on the formed path set, find the optimal distribution line switches reachable by network attacks to form a data set. First, check whether there is a network attack target switch upstream of other network attack target switches according to the upstream and downstream relationship. If so, delete all network attack target switches downstream of this switch. Then, check whether there are other switches that can replace the existing switch combination to simplify the switches, and form the final output as the scheme with the minimum additional loss.

[0051] 4. Output the scheme with the minimum number of attack switches (the second scheme):

[0052] Find the scheme with the minimum number of switches according to the iterative optimization algorithm. The specific steps are as follows:

[0053] 1) Take the switches obtained in the scheme with the minimum additional loss as the target switches, and sort the importance of these distribution line switches. The importance of the distribution line switches reachable by network attacks is mainly affected by many factors such as the location of their feeders and the user selection area. The core idea is to sort these switches according to the frequency of appearance in the paths obtained by the minimum path method (the higher the frequency of appearance, the higher the importance);

[0054] 2) Select the optimal distribution line switches reachable by network attacks according to the importance sorting and information such as the position of the switches on the feeder;

[0055] 3) Subsequently, evaluate the power outage situation in the target area to determine whether all power supply paths in the target area have been cut off. If the expected goal is achieved, provide the current all target switches as the output to the user. If the expected goal is not achieved, return to the first step and continue to loop.

[0056] 5. Output the optimal scheme for identifying key distribution network equipment:

[0057] By comparing the first two schemes, provide the user with the third optimal scheme. The specific steps are as follows:

[0058] 1) Calculate the additional additional loss caused by the scheme with the minimum number of output target switches;

[0059] 2) Compare with the scheme with the minimum additional output loss. If the resulting additional loss is greater than twice the target, then use the scheme with the minimum additional loss as the optimal scheme; otherwise, use the scheme with the fewest attack switches as the output.

[0060] A key equipment identification technology for distribution networks facing regional network attacks provided by the present invention specifically further includes the following content:

[0061] 1. Distribution network topology model:

[0062] In graph theory, a graph G is usually represented by (V(G), D(G)), where V(G) represents a non-empty finite set of nodes of the graph, and D(G) represents a non-empty finite set of edges of the graph. In a specific description, V(G) = {v1, v2,..., v} represents the node set of the graph, D(G) represents the edge set, and the edge d ∈ D(G) represents the connection relationship of the node pair {v i , v}. If v i and v are connected by the edge d, then v i and v are called the endpoints of this edge.

[0063] As Figure 1 shown, small black dots are usually used to represent nodes, and the line segments between small black dots represent edges. If the two endpoints of an edge coincide, then this edge is called a loop; if the endpoints of two edges are the same pair of nodes, then these two edges are called multiple edges. A graph containing loops or multiple edges is called a complex graph.

[0064] For a graph G, if it contains N nodes and M edges, it can be represented by an N×N adjacency matrix, denoted as A = [A i , where:

[0065]

[0066] In an undirected unweighted complex network model, the edges in the network have no directionality, and the weight of each edge is 1 without difference. That is, the edge d i = {v i , v} is equivalent to d i = {v, v i}, without considering the directionality between node pairs. The expression of the adjacency matrix A is as follows:

[0067]

[0068] In a distribution network, a transfer switch is an important device for realizing flexible load transfer. In the topological modeling of a distribution network, the state of the transfer switch has a direct impact on the representation of the adjacency matrix A. When the switch is in the open state (i.e., disconnected), it means that the relevant nodes are no longer connected. To reflect this state in the adjacency matrix, the elements corresponding to the row and column where the switch is located can be set to zero. That is, if the nodes vi or vj connected by the switch Sij are disconnected, all the rows and columns in the adjacency matrix A related to the nodes vi or vj are set to zero.

[0069] 2. Key equipment identification method for distribution network under deliberate network attacks:

[0070] 2.1 Distribution network wiring mode recognition:

[0071] When identifying distribution network equipment, it is necessary to consider the network topology structure to ensure the accuracy of identification. Therefore, it is necessary to analyze the typical distribution network topology structure to ensure the universality of the design scheme. The typical distribution network topology structures mainly include: basic radial distribution network, radial-connected distribution network, normally open loop distribution network, and normally closed loop distribution network. For these four distribution network topology structures, it is necessary to consider whether the minimum path method can find all the power supply paths of all key target users in the selected area.

[0072] The radial distribution network transmits electric energy from the substation to the load branches radially through distribution lines. Each line is independently powered, and there is no electrical connection between the lines. It is suitable for areas with low load density, such as rural power grids or small load areas. For the radial distribution network, the minimum path method can effectively search all possible power supply paths from the power source to each load point. Since the structure of the radial distribution network is relatively simple, there is generally only one power supply path for important targets. When using the minimum path method for path search, it can ensure that all reachable power supply paths for important targets are accurately found.

[0073] The radial-connected distribution network is based on the radial distribution network and adds connection lines. Two or more main feeders led out from the same substation are connected by normally open switches. On the premise that the substation does not fail, the two feeders are backup to each other, which improves the power supply reliability compared with the radial distribution network. When the main line fails, the power supply can be restored through the connection line. Generally, there are multiple power supply paths for important targets in this structure, and it is necessary to take all possible circuit breakers in front of the substations as the search targets of the minimum path method.

[0074] Similar to the radial-connected distribution network, the normally-open loop topology connects two main feeders drawn from the same substation through a tie switch SWITCH. The difference is that the branch lines of the radial-connected type are only isolated from faults by fuses, while the branch lines of the normally-open loop distribution network are equipped with sectionalizing switches. The lines are arranged in a loop layout and are usually in an open-loop operation state to avoid forming a closed loop. Each loop has multiple switches, and the open-loop point is usually located at a position with lower load or in the middle, which is suitable for areas with a high load density and high power supply reliability requirements, such as large industrial areas or urban power grids. For such a topological structure, the minimum path method search also needs to target all possible circuit breakers in front of the substations. In addition, it should be noted that there may be a loop formed within a single feeder and it operates in an open-loop state. In this case, simply using the basic minimum path method for search will cause a possible power supply path to be ignored. Therefore, some switches need to be set to zero to find this possible power supply path.

[0075] The normally-closed loop distribution network remains closed during normal operation, and the power supply and load points are connected through multiple paths. This structure is used to improve the current distribution in the distribution network, reduce voltage drop and power loss, and is suitable for highly concentrated load areas or places with extremely high requirements for power supply continuity, such as important industrial bases, large urban centers or critical infrastructure areas. For key targets, the power supply reliability is very high, and any single line fault will not cause the load to lose power. Its minimum path search method is similar to that of the normally-open loop type, but due to the reduction of normally-open switches, this topological structure requires more attack targets.

[0076] The ATS (Automatic Transfer Switch) is a device used for automatic power supply switching. Its main function is to switch the load line from one power supply side to another to ensure the continuity and reliability of power supply. In the power system, the ATS monitors the power supply status in real time through the built-in control logic. When the main power supply fails (such as power outage, undervoltage or overvoltage), it can quickly trigger the standby power supply or route and automatically switch the load to the standby power supply or route for power supply; when the main power supply returns to normal, the ATS will switch the load back to the main power supply according to the preset logic, and at the same time turn off the standby generator to restore the normal operation of the system.

[0077] For urban distribution networks with multiple power supplies and frequent power transfer, the distribution network structure is generally not a simple radial topology, which makes the power supply methods for key target users often diverse and complex. Multiple power supplies mean that multiple upper-level nodes supply electric energy to users, and multiple power transfer paths refer to the existence of multiple ATSs (Automatic Transfer Switches) and transfer switches such as normally-open / normally-closed in the distribution network. Therefore, in this case, it is necessary to improve on the basis of the minimum path method to find all the paths for power supply.

[0078] 2.2 Identification of power supply paths for users in regional distribution networks based on the improved minimum path method:

[0079] The minimum path search algorithm is a graph - theory - based search algorithm, mainly used to find the optimal power supply path from the power source point to the load point in the distribution network. This algorithm first determines the network structure through topological analysis. Using the adjacency matrix or other graph representation methods, it gradually searches all possible paths from the power source node to the target load node, and filters out the paths that do not contain redundant devices and meet the power supply conditions as the minimum paths. The devices on the minimum path play a decisive role in the power supply reliability of the load point, and their failure will directly lead to the interruption of power supply at the load point; while the components on the non - minimum path have an indirect impact on the reliability according to their association degree with the minimum path.

[0080] This invention focuses on considering the influence of normally - open switches and ATS on the identification of key devices in the distribution network. In the distribution network with normally - open switches and ATS (Automatic Transfer Switch), the improvement of the minimum path is mainly reflected in the fact that accurate search can still be achieved when the transfer switch switches and the standby path is introduced. When the main path fails, the transfer switch can quickly switch to the standby path, thus maintaining the power supply at the load point. At this time, the standby path becomes the new minimum path. Therefore, when calculating the minimum path, the standby path after transfer needs to be incorporated into the model to improve the applicability of the algorithm to complex networks. In addition, the introduction of the standby path with ATS makes the search process of the minimum path more complex. If the power capacity of the standby path can meet the demand of the load point, the standby path can completely replace the main path, thus significantly reducing the power outage time at the load point; if the capacity is insufficient, it is necessary to prioritize the load points to ensure that critical loads are powered first. By integrating the characteristics of the transfer switch and the standby path into the minimum path algorithm, the actual operation of the network can be more comprehensively reflected, thus improving the accuracy of the power supply reliability assessment.

[0081] The liaison matrix method is an analysis method based on the network topological structure, mainly used to systematically solve all the minimum paths between the input node and the output node. By calculating the multiple powers of the liaison matrix, all possible paths between nodes in the network can be comprehensively explored, especially suitable for the analysis of complex network structures and the identification of critical paths.

[0082] Suppose there are n nodes in the network, and the liaison matrix A = [A ij is an n×n matrix, and its element A ij is defined as follows: ① If there is a direct connection (i.e., there is an edge) between node i and node j, then A ij = 1; ② If there is no direct connection between node i and node j, then A ij = 0. To find the minimum path set of longer paths, it is necessary to perform power operations on the liaison matrix A. Ar = [A ij (r)], where A ij(r) represents the number of all paths with a path length of r from node i to node j. The calculation formula is as follows:

[0083]

[0084] Among them, "·" represents the multiplication operation of matrices.

[0085] By calculating matrix A r , the increase in the matrix power can intuitively represent the change in the path length between nodes. For example, matrix A represents paths of length 1; matrix A 2 represents paths of length 2; matrix A 3 represents paths of length 3, and so on. By performing multiple power operations on the connection matrix, the connectivity of different path lengths can be systematically analyzed. In this process, by selecting the matrix with the smallest power r, all the shortest paths from any target user to the power source point can be effectively extracted, thereby realizing path optimization and analysis.

[0086] In summary, for the minimum path search for the identification of key equipment in the regional distribution network, first, all associated feeders in the target area need to be modeled as an undirected graph; second, all key users in the target area are used as the initial nodes, and the circuit breakers of all distribution transformers on the feeders where the users are located and on the upper levels of the connecting feeders are used as the targets; then, according to different network structures and types of connecting switches, the minimum path algorithm is used to search from the initial nodes to the targets respectively, and finally, all possible minimum paths that can supply power to important users in the target area are obtained, and a minimum path table is formed.

[0087] 2.3 Principle of the iterative optimization algorithm:

[0088] In the process of minimizing the additional loss and the number of attack switches, the key equipment identification scheme for the distribution network aims to determine the optimal scheme to disable all important users in the selected area by applying the iterative optimization algorithm. This algorithm uses a step-by-step iterative method to approach the optimal solution, and adjusts according to the state of the current solution in each iteration, thereby continuously optimizing the quality of the solution.

[0089] The iterative optimization algorithm usually starts from an initial solution. In this scheme, the initial solution is obtained by screening after sorting the importance of the distribution line switches reachable by network attacks on the power supply path. Subsequently, the algorithm gradually optimizes the quality of the solution by repeating specific steps. In each iteration, a potentially better solution is generated using the information of the current solution until the stop condition is met, such as reaching the maximum number of iterations or the improvement amplitude of the solution is lower than the preset threshold.

[0090] In the scenario where the distribution network faces regional cyberattacks, the attacker selects and operates the line switches within the selected area to carry out the attack, thereby achieving precise power outages for all key target users within the area. To address this issue, this solution first selects the target area and determines all key target users within the area; then, based on the improved minimum path method search, it determines the power supply paths of all distribution transformers and their users within the area; next, it sorts the distribution line switches that can be reached by cyberattacks on the power supply paths according to their importance; finally, it decides the actions of the line switches through an iterative optimization algorithm and outputs the planned power outage plan for the distribution network area. Through iterative optimization, this solution can effectively identify the key equipment of the distribution network, providing a scientific basis and technical support for improving network security protection capabilities and power supply reliability.

[0091] The specific process of optimizing the scheme for disabling important users within the area based on the iterative optimization algorithm is as follows:

[0092] 1. Optimization of the scheme with the minimum additional loss:

[0093] The goal of this scheme is to find the scheme with the minimum additional loss Ladd by adjusting the combination of cyberattack target switches. Its implementation process is mainly divided into the following steps:

[0094] 1) Search for the equipment combination with the minimum additional loss: From the perspective of the attacker, based on the minimum path principle, find all attackable equipment combinations S that are closest to the target load;

[0095] 2) Quickly judge the upstream and downstream relationships: Based on the above equipment combination S, according to the upstream and downstream relationships in the topological structure, quickly delete and replace redundant switch combinations to reduce the number of switches that need to be calculated. For example, if switch S i is located upstream of S j , then by controlling the disconnection of S i , the disconnection of S j can be indirectly controlled, and then delete S j and its downstream switches to reduce redundant combinations, S′ = S / {s j |s j is located downstream of s i};

[0096] 3) Simplification of the switch combination: Through path search, preferentially select the switches that can cover more paths, that is, judge whether there are fewer switches that can replace the existing combination without causing additional load loss. For example, if a certain switch S c can replace the combination {S a , S b}, then update it to: S″ = S′ / {s a , s b} ∪ {s c};

[0097] 4) Calculation of additional losses: Based on the additional loss contribution value ΔP of each switch i , preferentially select the switch combination with a smaller additional loss Ladd. The calculation formula is:

[0098]

[0099] 2. Optimization of the scheme with the fewest attack switches:

[0100] The goal of this scheme is to further optimize based on the scheme with the minimum additional loss, so as to find the scheme with the fewest attack switches |S min |. The implementation process mainly includes the following steps:

[0101] 1) Sorting of switch importance: The iterative optimization algorithm preferentially selects the switch with the greatest impact on the path by calculating the frequency of each network attack reachable switch in the path. And evaluate whether the current combination can cut off all power supply paths. If the current combination S k can cut off all power supply paths in the target area and there is no simpler switch combination, then S min = S k ;

[0102] 2) Loop optimization: If the goal is not reached, re - sort and select the next group of switches to continue optimization.

[0103] 3) Calculation of additional losses: Based on the additional loss contribution value ΔP of each current switch i , calculate the current additional loss L′ add . The calculation formula is:

[0104]

[0105] 3. Optimization of the optimal scheme for identifying key equipment in the distribution network

[0106] This scheme aims to comprehensively consider the two strategies of minimizing additional losses and minimizing the number of attack switches, balance the two, and finally output the optimal scheme S for identifying key equipment in the distribution network final . In the specific implementation process, by setting the maximum allowable value of load loss, optimize Scheme 1 (minimizing additional losses) and Scheme 2 (minimizing the number of attack switches). For example, when the maximum allowable value is set to 2, if the additional loss L′ of the scheme with the fewest attack switches add exceeds twice that of the scheme with the minimum additional loss, then preferentially select Scheme 1 with a lower additional loss; otherwise, select Scheme 2 with fewer attack switches. Through this optimization mechanism based on constraint conditions, it is possible to achieve the global optimization of the key equipment identification scheme while ensuring the reliability of the system.

[0107]

[0108] The iterative optimization algorithm runs through the whole process of path search, solution optimization and result comparison, and is a key tool for solving complex distribution network optimization problems.

[0109] When there is an ATS or a normally open switch in the power supply path of an important target to transfer power to the backup power supply, the present invention can accurately search for these backup paths; and can minimize the number of strike switches on the premise of cutting off all power supply paths to disable the important target.

[0110] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one Figure 1 one process or multiple processes and / or blocks Figure 1 means for implementing the functions specified in one block or multiple blocks.

[0111] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more, unless otherwise specifically defined.

[0112] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A method for identifying key equipment in a distribution network facing regional network attacks, characterized in that, Including the following steps: Based on the distribution network topology model, identify the wiring mode of the distribution network and obtain the power supply paths of the users in the regional distribution network; Based on the power supply paths, obtain a data set of the distribution line switches reachable by the optimal network attack, form a first solution with the minimum additional loss, and find a second solution with the minimum number of switches according to the iterative optimization algorithm; Identify the key equipment of the distribution network according to the first solution or the second solution.

2. The method for identifying the key equipment of a distribution network for regional network attacks according to claim 1, wherein: In the process of obtaining the distribution network topology model, perform topology modeling on the distribution network based on the research of complex network theory.

3. The method for identifying the key equipment of a distribution network for regional network attacks according to claim 2, wherein: When obtaining the power supply paths of the users in the regional distribution network, model all the associated feeders in the target area as an undirected graph; take all the key users in the target area as the initial nodes, and the circuit breakers of all the distribution transformers on the feeders where the users are located and on the upstream of the tie feeders as the targets; according to different network structures and tie switch types, respectively use the minimum path algorithm to search from the initial nodes to the targets to obtain all the possible minimum paths for supplying power to the important users in the target area, and form a minimum path table as the power supply paths of the users in the regional distribution network.

4. The method for identifying the key equipment of a distribution network for regional network attacks according to claim 3, wherein: When obtaining the first solution, check whether there is a network attack target switch upstream of other network attack target switches according to the upstream and downstream relationship. If so, delete all the network attack target switches downstream of this switch, and then check whether there are other switches that can replace the existing switch combination for switch simplification to form the first solution.

5. The method for identifying the key equipment of a distribution network for regional network attacks according to claim 4, wherein: When using the iterative optimization algorithm, perform importance ranking on the distribution line switches reachable by the network attack on the power supply paths and then screen to obtain the initial solution. Through the iterative optimization algorithm, repeat specific steps to gradually optimize the quality of the initial solution; In each iteration, generate a possibly better solution using the information of the current solution until the stop condition is met.

6. The method for identifying the key equipment of a distribution network for regional network attacks according to claim 5, wherein: When obtaining the second solution, take the switches obtained in the solution with the minimum additional loss as the target switches and perform importance ranking; select the optimal distribution line switches reachable by the network attack according to the importance ranking and the position information of the switches on the feeders; evaluate the power outage situation in the target area to determine whether all the power supply paths in the target area have been cut off. If so, reach the expected goal and provide all the current target switches to the user as the output. If not, return and continue to loop to obtain the second solution with the minimum number of switches.

7. The method for identifying the key equipment of a distribution network for regional network attacks according to claim 6, wherein: When identifying key distribution network equipment, the additional losses caused by the second solution; compared with the first solution, if the additional losses are more than twice the target, the solution with the minimum additional losses is taken as the optimal solution, otherwise the solution with the least number of attacked switches is taken as the output. Based on the output result, key distribution network equipment is identified.

8. A key equipment identification system for distribution network facing regional network attacks, characterized in that, It includes: A path planning module, configured to identify the wiring mode of the distribution network based on the distribution network topology model and obtain the power supply paths of the users in the regional distribution network; A solution acquisition module, configured to obtain a data set of distribution line switches that can be reached by an optimal network attack based on the power supply paths, form a first solution with the minimum additional losses output, and find a second solution with the least number of switches according to the iterative optimization algorithm; An identification module, configured to identify key distribution network equipment according to the first solution or the second solution.

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