Cascade failure mitigation method and system for power system based on accident and disaster background

Abstract

The application discloses a kind of power system cascading failure mitigation method and system based on accident disaster background, facing engineering actual demand, for the cascading failure of power system, first according to the risk level of disaster accident, establish equipment risk index, and utilize these indexes to refine the development mode of system cascading failure under disaster scenario.And from the angle of operation control, combined with optimal generator scheduling and load / generator shedding method, the coordinated mitigation strategy of system cascading failure under disaster conditions is formulated;The strategy is combined with active preventive measures, aims to quickly cut off the potential cascading failure path at the first time after disaster occurs, so as to minimize the affected outage area;The application can effectively reduce the influence of disaster accident on power system operation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power supply, and particularly relates to a power system cascading failure mitigation method and system in the context of accidents and disasters. BACKGROUND

[0002] Under the background of global climate change, extreme weather and climate events occur frequently. According to statistics of the China Electric Power Reliability Management Center, natural disasters and climate factors are the main reasons for planned outages of overhead transmission lines. Line failures caused by natural disasters are unpredictable, and the resulting impact increases the risk of secondary cascading failures in the power grid. Therefore, developing a cascading failure mitigation strategy at the operational level is of great significance for suppressing the propagation of cascading failures in the power system and minimizing the losses caused by disasters.

[0003] Under disaster weather conditions, a minor failure can spread to a large area of the power system and may lead to significant load reduction due to cascading failures. Comprehensive and accurate analysis of cascading failures can be effectively used for risk assessment, critical component identification, and solving other related problems. In addition, in cascading failure analysis, theoretically any cascading path with arbitrary independent failure combination is possible. However, the computational complexity of finding high-order n-k contingency makes traditional enumeration and random search methods infeasible. Existing research has reduced the complexity of cascading failure analysis by selecting typical cascading failure propagation paths. However, these search criteria ignore the transmission lines that are most likely to cause corresponding failures.

[0004] According to the different control timing, the strategy to mitigate large-scale power outages caused by cascading failures can be roughly divided into two categories: pre-accident preventive control and in-accident emergency mitigation. Preventive control refers to taking corrective measures when the system is in an unsafe state to restore the system to a safe state, thereby ensuring the safe and stable operation of the system. In contrast, emergency mitigation measures implemented during an accident involve cutting off the cascading failure path to stop the further development of the failure. Existing cascading failure control research mostly ignores the impact of natural disasters on the operational risk of transmission lines, resulting in a relatively rough assessment of the actual operational risk level of the power system. In addition, current research tends to treat preventive control and mitigation control in isolation, ignoring their complementary characteristics in terms of economic efficiency and safety. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a power system cascading failure mitigation method and system based on the context of accidents and disasters, which solves the technical problems that existing research is difficult to assess the operational risk of transmission lines caused by natural disasters, and the control strategy for mitigating disasters is difficult to balance economic efficiency and safety.

[0006] The application adopts the following technical solutions:

[0007] A power system cascading failure mitigation method based on an accident disaster background, comprising the following steps:

[0008] A power system disaster accident risk index system is established according to the risk level of the disaster accident, and the development mode of system cascading failure under the disaster scenario is refined by using the power system disaster accident risk index system;

[0009] According to the cascading failure development mode caused by natural disasters, a cascading failure propagation model is established; according to the cascading failure propagation model, island identification in the power system is carried out based on the breadth-first search algorithm, the largest size and the highest weight coefficient subsystem is selected to form a new main system, and the cascading failure is continuously simulated;

[0010] The power system cascading failure risk is evaluated according to the system data before and after the failure obtained from the cascading failure propagation model; the cascading failure mitigation strategy including the mitigation control cost model and the coordination control model is established according to the power system cascading failure risk, the synergistic mitigation strategy of system cascading failure under disaster conditions is combined with the active prevention measures, and the potential cascading failure path is cut off after the disaster occurs.

[0011] Preferably, the development mode of system cascading failure under the disaster scenario is refined as follows:

[0012] When the overhead line disaster operation risk value is more than 1000, it is level 1, which has a major threat to cause major losses;

[0013] When the overhead line disaster operation risk value is between 300 and 1000, it is level 2, which means the possibility of serious loss;

[0014] When the overhead line disaster operation risk value is between 60 and 300, it is level 3, which means a considerable risk of serious loss;

[0015] When the overhead line disaster operation risk value is between 20 and 60, it is level 4, which means causing a larger loss;

[0016] When the overhead line disaster operation risk value is between 5 and 20, it is level 5, which means a moderate risk of general loss;

[0017] When the overhead line disaster operation risk value is less than 5, it is level 6, which is usually associated with the smallest or no risk of suffering a loss.

[0018] Preferably, the overhead line disaster operation risk value For:

[0019]

[0020] wherein, represents the natural disaster causing the probability of line failure; is the natural disaster causing the line failure damage value; represents the natural disaster causing the loss of transmission capacity value due to line failure, is the natural disaster causing the social impact coefficient of line risk, represents the total number of natural disasters.

[0021] Preferably, the natural disaster causing the social impact coefficient of line risk is:

[0022]

[0023] wherein, is the natural disaster causing the natural disaster risk period coefficient; represents the risk weight of the natural disaster .

[0024] Preferably, in the cascading failure propagation model, when the generator group scheduling cannot meet the power balance demand, two scenarios are included:

[0025] After a certain ramp-up period, if the output power of the generator is still greater than the system load value, the generator shedding needs to be carried out according to the generator shedding priority to achieve power balance;

[0026] If the system load continues to exceed the output power of the generator after a specified generator ramp-up period, it is necessary to coordinate load shedding measures according to the load shedding priority assigned to each load;

[0027] Based on the breadth-first search algorithm, the power system island is identified, and then the consequence severity is used to measure the scale of power system outage caused by cascading failure events with complete fault paths, and the average outage consequence of power system cascading failure is used to measure the risk of system cascading failure.

[0028] Preferably, the shedding priority of the generator node and the load shedding priority of the load node are specifically: ​

[0029]

[0030]

[0031] wherein, is a weight vector of the generator node , is the power generation output of the generator node , is a weight vector of the load node, is the load magnitude of the load node.

[0032] Preferably, the consequence severity and the average outage consequence are respectively:

[0033]

[0034]

[0035] wherein, is the initial system load node set; is the final system load node set; and are the load connected to the node before and after the fault occurrence, respectively; is the set of all branches in the system; is the number of elements in the set .

[0036] Preferably, the mitigation control cost model comprises:

[0037] the system operation risk indicator is the sum of the economic indicator and the outage risk indicator ;

[0038] the economic indicator of the coordinated control is the sum of the preventive control cost and the probability-weighted interruption mitigation control cost ; the outage risk indicator represents the total risk on all cascading fault paths;

[0039] the preventive control cost and the probability-weighted interruption mitigation control cost are respectively:

[0040]

[0041]

[0042] wherein, represents the cascading path control cost after control; , , , respectively represent the active power of the generator before preventive control, the active power of the generator after preventive control, the adjustment coefficient of the active power of the cascading fault and the generator .

[0043] Preferably, the coordinated control model comprises:

[0044] The objective of the coordinated control model is to obtain a control scheme with the minimum operating risk under a given network topology and weather condition, i.e. to minimize the power outage risk with the minimum control cost, and the objective function is:

[0045]

[0046] Preventive control power balance maintenance constraint:

[0047]

[0048] Power balance maintenance constraint after emergency mitigation:

[0049]

[0050] Preventive control line power flow constraint:

[0051]

[0052] Line power flow constraint after emergency mitigation:

[0053]

[0054] Adjustment load limit constraint after emergency mitigation:

[0055]

[0056] Generator output limit constraint:

[0057]

[0058]

[0059] wherein, is a load node Pre-control load; , , respectively represent line power flow after pre-control, cascading failure path emergency mitigation line power flow, limit value of line power flow, , represent the upper and lower limits of the active output of the generator , represent the cutting load amount of the load node during emergency mitigation, represent the number of generators, represent the number of loads, represent the cascading failure path.

[0060] In a second aspect, an embodiment of the present application provides an electric power system cascading failure mitigation system in an accident disaster background, comprising:

[0061] An index module, which establishes an electric power system disaster accident risk index system according to the risk level of the disaster accident, and uses the electric power system disaster accident risk index system to refine the development mode of system cascading failure under disaster scenarios;

[0062] A simulation module, which establishes a cascading failure propagation model according to the cascading failure development mode caused by natural disasters, and performs island identification in the electric power system based on the breadth-first search algorithm according to the cascading failure propagation model, selects the largest size and highest weight coefficient subsystem to form a new main system, and continuously simulates the cascading failure;

[0063] An output module, which evaluates the cascading failure risk of the electric power system according to the system data before and after failure obtained by the cascading failure propagation model, establishes a cascading failure mitigation strategy including a mitigation control cost model and a coordination control model according to the cascading failure risk of the electric power system, combines the cooperative mitigation strategy of system cascading failure under disaster conditions with active preventive measures, and cuts off potential cascading failure paths after the disaster occurs.

[0064] In a third aspect, a computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the above-mentioned electric power system cascading failure mitigation method in an accident disaster background when executing the computer program.

[0065] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium comprising a computer program, which, when executed by a processor, implements the steps of the above-mentioned electric power system cascading failure mitigation method in an accident disaster background.​

[0066] In a fifth aspect, a chip is provided, which includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor, and the processor implements the steps of the method for mitigating cascading failures of power system in the context of accidents and disasters when the computer program is executed.

[0067] In a sixth aspect, an electronic device is provided, which includes a computer program, and the computer program implements the steps of the method for mitigating cascading failures of power system in the context of accidents and disasters when the computer program is executed by the electronic device.

[0068] Compared with the prior art, the present application has at least the following beneficial effects:

[0069] A method for mitigating cascading failures of power system in the context of accidents and disasters, establishes a device risk index based on the risk level of disasters and accidents, which helps to refine the development mode of cascading failures within the system under the conditions of accidents and disasters; then, at the operation control level, the optimal generator dispatching and load / generator shedding techniques are used to develop a coordinated mitigation strategy for system cascading failures under disaster conditions; this strategy, together with proactive prevention and control measures, ensures that potential cascading failure paths are quickly cut off when disasters occur, thereby minimizing the area affected by power outages; in addition, the present application also develops a comprehensive disaster risk quantification theory, which takes into account the likelihood of risk occurrence, the degree of impact of risk on transmission lines, and the severity of potential harm; this framework can comprehensively quantify the operational risks related to overhead lines during disasters. Meanwhile, an evaluation method for cascading failures under disaster scenarios is established, which quantifies the degree of increase in cascading failure risk of the whole system due to disasters.

[0070] Further, refining the development mode of system cascading failures under disaster scenarios can summarize line failures caused by various natural disasters, so as to derive the probability of line failure under various natural disaster conditions using statistical analysis methods. This enables us to estimate the load loss caused by risks to regional power grids, and the capacity loss degree when the line fails is distributed according to the proportion of load loss.

[0071] Further, in the case of natural disasters leading to the outage of transmission lines, timely implementation of power balancing strategies is crucial to ensuring the stability of the power system. When the power system needs to take balancing measures at the time of disaster, the optimal strategy is to prioritize the dispatching operation of the generator ramp. This method requires an assessment of the interaction between generator output and system load, resulting in two different situations during generator dispatching: if the generators have excess output capacity, their output should be reduced accordingly, and if the total output of the generators is lower than the load, it is necessary to increase the output of the generators.

[0072] Further, when the generator set scheduling cannot meet the power balance requirement, coordinated load shedding and generator tripping measures need to be implemented to ensure that the power system reaches a balanced state. Generally, there are two scenarios: if the output power of the generator is still greater than the system load value after a certain ramp-up period, generator tripping needs to be performed according to the tripping priority of the generator to achieve power balance; if the system load continues to exceed the output power of the generator after a specified generator ramp-up period, it is necessary to coordinate load shedding measures according to the load shedding priority assigned to each load.

[0073] Further, the mitigation control implemented after triggering is adjusted for a single fault path, and conflicts only occur when the paths intersect and the mitigation measures are applied before the intersection. This reduces the conflicts between control measures. However, due to its post-fault nature, mitigation control often involves a large amount of control work because the fault has already had a significant impact on the system. Therefore, a mitigation control cost model needs to be established to reasonably select the timing of mitigation control.

[0074] Further, the goal of the coordinated control model is to obtain a control scheme with the minimum operating risk under a given network topology and weather condition, i.e., to minimize the power outage risk with the minimum control cost.

[0075] It can be understood that the beneficial effects of the above-mentioned second aspect can be referred to the related description in the above-mentioned first aspect, which will not be repeated here.

[0076] In summary, the present application rapidly cuts off potential cascading fault paths at the first time after a disaster occurs, thereby minimizing the affected outage area and effectively reducing the impact of the disaster on the operation of the power system.

[0077] The technical solutions of the present application will be further described in detail below with the aid of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0078] Figure 1 is a flowchart of the present application;

[0079] Figure 2 is a schematic diagram of the breadth-first search algorithm used in the present application;

[0080] Figure 3 is a schematic diagram of a computer device provided by an embodiment of the present application;

[0081] Figure 4 is a block diagram of a chip provided by an embodiment of the present application;

[0082] Figure 5 is a display diagram of the evaluation results of the cascading faults of the power system according to the present application;

[0083] Figure 6 A display diagram of the result of the preventive control of the cascading failure of the power system according to the present application. DETAILED DESCRIPTION

[0084] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of the present application.

[0085] In the description of the present application, it should be understood that the terms “include” and “contain” indicate the existence of described features, whole, steps, operations, elements and / or components, but do not exclude the existence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0086] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms “a”, “an” and “the” are intended to include plural forms unless the context clearly indicates otherwise.

[0087] It should be further understood that the term “and / or” used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations, for example, A and / or B can represent three cases of A alone, A and B together, and B alone. In addition, the character “ / ” in the present application generally represents an “or” relationship between the front and rear associated objects.

[0088] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present application to describe the preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, the first preset range can also be referred to as the second preset range, and similarly, the second preset range can also be referred to as the first preset range without departing from the scope of the embodiments of the present application.

[0089] Depending on the context, the word “if” as used herein can be interpreted as meaning “when” or “while” or “in response to determining” or “in response to detecting”. Similarly, depending on the context, the phrase “if it is determined” or “if (a stated condition or event) is detected” can be interpreted as meaning “when it is determined” or “in response to determining” or “when (a stated condition or event) is detected” or “in response to detecting (a stated condition or event)”.

[0090] Various structural diagrams according to the disclosed embodiments of the present application are shown in the drawings. These diagrams are not drawn to scale, in which certain details are exaggerated for clarity of presentation and may be omitted. The shapes of various regions, layers shown in the drawings and their relative sizes and positional relationships are merely exemplary, and in actuality may deviate due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes, relative positions can be additionally designed by those skilled in the art according to actual needs.

[0091] The present application provides a power system cascading failure mitigation method in the context of accidents and disasters, which is oriented to engineering practical needs and aims at cascading failures of power systems. Firstly, equipment risk indicators are established according to the risk level of disaster accidents, and the development mode of system cascading failure under disaster scenarios is refined using these indicators. From the perspective of operation control, combined with optimal generator scheduling and load / generator shedding methods, a coordinated mitigation strategy for system cascading failure under disaster conditions is developed. This strategy, combined with proactive preventive measures, aims to quickly cut off potential cascading failure paths at the first time after the disaster occurs, thereby minimizing the affected outage area.

[0092] Referring to Figure 1 , the present application is a power system cascading failure mitigation method in the context of accidents and disasters, comprising the following steps:

[0093] S1, establishing risk indicators according to the risk level of power system disaster accidents, and refining the development mode of power system cascading failure under various natural disaster conditions using the risk indicators;

[0094] According to the current definition of safety risk, it includes the comprehensive assessment of the possibility of adverse effects and the severity of danger. This definition has been expanded to include the risk table of overhead transmission lines under natural disaster conditions. According to the risk level of power system disaster accidents, a power system disaster accident risk indicator system is established, and the development mode of power system cascading failure under various natural disaster conditions is refined using these indicators.

[0095] The risk value of natural disasters affecting overhead transmission lines is defined as , the probability of overhead line failure caused by natural disasters is , and the severity of the damage caused by the fault is , then

[0096] (1)

[0097] wherein, is divided into two parts, which are calculated by statistical analysis respectively:

[0098] (2)

[0099] where, is the probability of natural disaster occurrence; represents the probability of failure caused by disaster.

[0100] the severity of damage caused by failure The calculation method is as follows:

[0101] (3)

[0102] where, is the line failure transmission capacity loss value; represents the social impact risk coefficient.

[0103] The formula (3) is extended to the case of comprehensive influence of multiple natural disasters; considering that different types of natural disasters occur in different periods, the corresponding risk characteristics and hazards are different, the period coefficient of natural disaster risk and the risk weight of natural disaster are introduced, and the social impact coefficient of a certain natural disaster risk is obtained as:

[0104] (4)

[0105] where, is the natural disaster caused by the line risk social impact coefficient; is the natural disaster caused by the natural disaster risk period coefficient; represents the risk weight of natural disaster .

[0106] The disaster operation risk of overhead transmission line is a comprehensive function of risk failure probability, line failure transmission capacity loss value and risk social impact coefficient, and its calculation formula is

[0107] (5)

[0108] where, is the value of overhead line disaster operation risk; represents the probability of natural disaster leading to line failure; is the line failure damage value under natural disaster ; represents the transmission capacity loss value caused by line failure under natural disaster .

[0109] According to the value of , the risk can be divided into different damage levels, as follows:

[0110] Values over 1000 are classified as level 1, posing a significant threat with major losses;

[0111] Values between 300 (not included) constitute level 2, indicating a possibility of severe losses;

[0112] Values between 60 and 300 (not included) are assigned to level 3, indicating a considerable risk of severe losses;

[0113] Conversely, Values in the range of 20 to 60 (not included) represent level 4, which tends to trigger greater losses;

[0114] Level 5 includes Values between 5 and 20 (not included) indicate a moderate risk of general losses.

[0115] Finally, below 5 Values belonging to level 6 are usually associated with the smallest or no risk of suffering losses.

[0116] Then, using statistical analysis methods, the probability of line failure under various natural disaster conditions is derived. The Monte Carlo method is then used to simulate the operation of the line during the disaster, thus calculating the potential forced outage duration. This allows us to estimate the load loss caused by the risk to the regional power grid.

[0117] Above, step S1 summarizes the line failures caused by various natural disaster risks, comprehensively quantifying the severity of the risk disaster.

[0118] S2, based on the development mode of the power system cascade failure under various natural disaster conditions obtained in step S1, establishes a cascade failure propagation model under natural disasters;

[0119] When a disaster occurs, the optimal strategy when the power system needs to take balancing measures is to prioritize the generator ramping of dispatch operations. At this time, it is necessary to assess the interaction between the output and the system load, resulting in two different situations in the process of generator dispatching; if the generators have excess output capacity, their output should be reduced accordingly.

[0120] (6)

[0121] where, Pdisrepresents the active power output of the generator adjusted in response to the disaster event. Pdisprepresents the active power output of the generator before the post-disaster reduction; Pdisprepresents the active power output of the generator​ the rate of downward adjustment of the generator per minute; and denote the set of load nodes and the set of generator nodes in the system, respectively; denotes the power adjustment period after the disaster event, usually set to 5 minutes to speed up power balance; is the active load of the load node.

[0122] If the total output of the generator is lower than the load, it is necessary to increase the output of the generator.

[0123] (7)

[0124] where, denotes the rising rate of the generator .

[0125] When the output of the generator meets formula (8) relative to the load, or when the output power reaches the maximum output power of the generator, the scheduling process of the generator is terminated.

[0126] (8)

[0127] where, is the convergence coefficient, which can be set according to the accuracy condition.

[0128] In step S2, when the generator group scheduling cannot meet the power balance requirement, it is necessary to implement coordinated load shedding and generator tripping measures to ensure that the power system reaches a balanced state. There are generally two scenarios:

[0129] After the generator goes through a certain ramp-up period, if its output power is still greater than the system load value, it is necessary to trip the generator according to the generator tripping priority to achieve power balance. The tripping priority of the generator node is determined by its power output and the weight vector . The calculation formula of the priority is as follows:

[0130] (9)

[0131] If the system load continues to exceed the output power of the generator after a specified generator ramp-up period, it is necessary to coordinate load shedding measures according to the load shedding priority assigned to each load. The load shedding priority of the load node is determined by its load magnitude and the weight vector . The formula for calculating the priority is:

[0132] (10)

[0133] The third part of step S2 is to identify power system islands based on a breadth-first search algorithm. During the development of cascading faults, the power system disintegrates, resulting in several isolated subsystems, commonly referred to as "islands." These islands lose all interconnections, and each island has a unique topology, power flow dynamics, and potential fault paths leading to continued cascading faults.

[0134] This invention employs a breadth-first search (BFS) algorithm to identify the occurrence of these islands. BFS is a traversal algorithm for graph data structures that starts from a specified initial vertex and explores the graph layer by layer in a breadth-first manner until the target node is found or the entire graph is traversed. Essentially, BFS embodies an iterative method where the search starts from the source node and propagates outwards, using a queue to maintain the discovered nodes, which then serve as the basis for further expansion, thereby achieving traversal of the entire graph. The system is decomposed into multiple isolated subsystems, and the subsystem with the largest size and highest weight coefficient is selected to form a new master system. This selection criterion ensures that cascading failures are continuously simulated in the newly formed master system.

[0135] The final step in step S2 is to assess the risk of cascading failure and the severity of the consequences. Used to measure the magnitude of power system outages caused by cascading failure events with complete fault paths. The average outage consequence of a cascading power system failure. To measure the risk of cascading failures in the system. and The calculation formula is as follows:

[0136] (11)

[0137] (12)

[0138] in, This is the initial set of system load nodes; This represents the set of load nodes in the final system; and These represent the access nodes before and after the fault occurred, respectively. The load; It represents the set of all branches in the system; Represents a set The number of elements in the system, i.e., the number of branches in the system; The higher the value, the more severe the power outage consequences caused by potential cascading fault events in the system.

[0139] S3. Based on the severity of the consequences obtained in step S2, establish a cascaded fault mitigation strategy, including a mitigation control cost model and a coordinated control model, to determine the timing of mitigation intervention. According to the time sequence of control measures, the control of large-scale power outage accidents can be divided into pre-accident prevention control and in-accident interruption control.

[0140] Because preventative controls are implemented before cascading failure paths are triggered, they take effect immediately upon failure, effectively minimizing the risk of the system being exposed to their effects. However, since they address all potential failure paths, while reducing path-related risks, they may inadvertently increase the risks of other paths. The conflicting requirements posed by different failure paths limit the effectiveness of relying solely on preventative controls to mitigate outage risks. Conversely, mitigation controls implemented after triggering adjust for individual failure paths, and conflicts only arise if paths intersect and mitigation measures are applied before the intersection. This reduces conflicts between control measures. However, due to their post-fault nature, mitigation controls often involve significant control effort, as the failure has already had a substantial impact on the system. By implementing preventative controls before a failure occurs, the need for subsequent mitigation controls is reduced, lowering control costs. Conversely, implementing post-fault mitigation controls can alleviate the inherent contradictions of preventative controls and improve the overall ability to reduce system risk. Therefore, preventative and mitigation controls are highly complementary.

[0141] To better select the timing of mitigation interventions, the risk salience of a fault segment is defined to represent the degree of impact of a fault segment within the same cascaded fault path on the overall path. Its expression is as follows:

[0142] (13)

[0143] in, The risk is a cascading failure path. The former Risk of power outage in the section; Indicates cascading fault paths The former The risk of power outages in the section.

[0144] The higher the value, the greater the contribution of that segment to the formation of propagation failure paths. Implementing mitigation controls at the highest risk level can effectively reduce the risk of fault paths and prevent the development of cascading faults.

[0145] Step S3 involves establishing a mathematical model to mitigate control costs, specifically coordinating economic indicators for control. The sum of prevention and control costs and probability-weighted interruption mitigation control costs is used to determine the power outage risk indicators. represents the total risk on all cascading failure paths. Since the impact of control measures on the power system is manifested as a change in the outage risk, and these control measures themselves incur control costs, in order to comprehensively evaluate the changes in the outage risk and control costs, the system operation risk index is defined as the sum of the economic index and the outage risk index.

[0146] (16)

[0147] (17)

[0148] (18)

[0149] (19)

[0150] (20)

[0151] Dear in

[0152] wherein, represents the prevention cost; represents the cascading path after control; represents the sum of the emergency mitigation costs of each cascading failure path after prevention control; represents the sum of the probability-weighted emergency mitigation costs of each cascading failure path after prevention control. , , , respectively represent the active power of the generator before prevention control, the active power of the generator after prevention control, and represent the adjustment coefficient of the active power of the generator to the cascading failure path and the generator after prevention control; represents an amplification factor; and respectively represent the cut load amount and the load loss cost coefficient of the load node during emergency mitigation of the cascading failure path ; is the implementation probability of the emergency mitigation of the cascading failure path .

[0153] Another part of step S3 is a coordinated control model, and the goal of the coordinated control model is to obtain a control scheme with the minimum operation risk under a given network topology and weather condition, i.e., to minimize the outage risk with the minimum control cost.

[0154] The mathematical optimization model is as follows:

[0155] (twenty two)

[0156] (twenty three)

[0157] (twenty four)

[0158] (25)

[0159] (26)

[0160] (27)

[0161] (28)

[0162] (29)

[0163] in, For load nodes Loads after prevention and control; , , They represent Power flow after line-based preventive control, cascading fault paths After emergency relief Line power flow, Limits of line power current, , Indicates generator The upper and lower limits of the active power output.

[0164] Equations (23) and (24) represent the power balance maintenance after prevention and control and emergency mitigation, respectively. Equations (25) and (26) represent... The online load does not exceed its limit after preventive control and emergency mitigation. Equation (27) ensures that the adjusted load does not exceed its limit after emergency mitigation, assuming that the maximum load reduction of the load node is 50% of its total load; finally, Equations (28) and (29) respectively represent the constraint that the generator output after preventive control and emergency mitigation does not exceed its limit.

[0165] Furthermore, if we only consider preventive control measures for all cascading failure paths before the failure occurs, that is, only retain the set... In , removing constraints (24), (26), (27), (29), the model is converted into a pure preventive control model. Conversely, if only emergency mitigation measures specific to each cascading failure path are considered, i.e. only are retained in the set , and constraints (23), (25) and (28) are removed, the model is converted into a pure emergency mitigation model.

[0166] In another embodiment of the present application, a cascading failure mitigation system for power systems in the context of accidents and disasters is provided, which can be used to implement the cascading failure mitigation method for power systems in the context of accidents and disasters described above. Specifically, the cascading failure mitigation system for power systems in the context of accidents and disasters includes an index module, a simulation module and an output module.

[0167] The index module establishes a power system disaster accident risk index system according to the risk level of the disaster accident, and uses the power system disaster accident risk index system to refine the development mode of cascading failure in the system under the disaster scenario.

[0168] The simulation module establishes a cascading failure propagation model according to the cascading failure development mode caused by natural disasters, performs island identification in the power system based on the breadth-first search algorithm based on the cascading failure propagation model, selects the subsystem with the largest size and the highest weight coefficient to form a new main system, and continuously simulates the cascading failure.

[0169] The output module evaluates the cascading failure risk of the power system according to the system data before and after the failure obtained from the cascading failure propagation model, establishes a cascading failure mitigation strategy including a mitigation control cost model and a coordination control model based on the cascading failure risk of the power system, combines the cooperative mitigation strategy of system cascading failure under disaster conditions with active preventive measures, and cuts off potential cascading failure paths after the disaster occurs.

[0170] In another embodiment of the present application, a terminal device is provided, which comprises a processor and a memory, the memory being configured to store a computer program, the computer program comprising program instructions, and the processor being configured to execute the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, and are suitable for implementing one or more instructions, and are particularly suitable for loading and executing one or more instructions to implement a corresponding method flow or a corresponding function; the processor in the embodiments of the present application can be used for the operation of the power system cascading failure mitigation method in the context of accidents and disasters, including:

[0171] According to the risk level of the disaster accident, a power system disaster accident risk index system is established, and the development mode of system cascading failure under the disaster scenario is refined by using the power system disaster accident risk index system; according to the cascading failure development mode caused by natural disasters, a cascading failure propagation model is established; according to the cascading failure propagation model, island identification in the power system is performed based on a breadth-first search algorithm, the largest size and the highest weight coefficient subsystem is selected to form a new main system, and the cascading failure is continuously simulated; the system data before and after the failure obtained according to the cascading failure propagation model is used to evaluate the cascading failure risk of the power system; according to the cascading failure risk of the power system, a cascading failure mitigation strategy including a mitigation control cost model and a coordination control model is established, the synergistic mitigation strategy of system cascading failure under disaster conditions is combined with active preventive measures, and the potential cascading failure path is cut off after the disaster occurs.

[0172] Please refer to Figure 3 , the terminal device is a computer device, the computer device 60 of the embodiment includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61, and the computer program 63 implements the fluid composition calculation method in the reservoir reconstruction wellbore in the embodiment when executed by the processor 61, to avoid repetition, which will not be described here. Alternatively, the computer program 63 implements the functions of each model / unit in the power system cascading failure mitigation system in the context of accidents and disasters when executed by the processor 61, to avoid repetition, which will not be described here.

[0173] The computer device 60 can be a desktop computer, a notebook computer, a palm computer, a cloud server, and the like. The computer device 60 can include, but is not limited to, a processor 61, a memory 62. Those skilled in the art can understand that Figure 3 The computer device 60 is only an example and does not constitute a limitation on the computer device 60, and can include more or fewer components than shown, or combine certain components, or different components, for example, the computer device can also include an input / output device, a network access device, a bus, and the like.

[0174] The processor 61 can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, and the like. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0175] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or a memory of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, and the like.

[0176] Further, the memory 62 can include both an internal storage unit and an external storage device of the computer device 60. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0177] Please refer to Figure 4 The terminal device is a chip, and the chip 600 of the embodiment includes a processor 622, the number of which can be one or more, and a memory 632 for storing a computer program executable by the processor 622. The computer program stored in the memory 632 can include one or more than one module each corresponding to a set of instructions. In addition, the processor 622 can be configured to execute the computer program to perform the power system cascade failure mitigation method in the accident disaster context described above.

[0178] Additionally, the chip 600 can also include a power supply component 626 that can be configured to perform power management of the chip 600, and a communication component 650 that can be configured to enable communication of the chip 600, e.g., wired or wireless communication. Further, the chip 600 can also include an input / output interface 658. The chip 600 can operate based on an operating system stored in the memory 632.

[0179] In still another embodiment of the present application, the present application also provides a storage medium, specifically a computer readable storage medium, which is a memory device in a terminal device, used for storing programs and data. It can be understood that the computer readable storage medium herein can include an internal storage medium of the terminal device, and of course can also include an expansion storage medium supported by the terminal device. The computer readable storage medium provides a storage space, which stores an operating system of the terminal. Moreover, one or more instructions adapted to be loaded and executed by a processor are also stored in the storage space, and the instructions can be one or more computer programs. It should be noted that the computer readable storage medium herein can be a high-speed RAM memory, or a non-volatile memory such as at least one disk memory.

[0180] The one or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the power system cascading failure mitigation method in the above-mentioned embodiments related to the background of the accident disaster; the one or more instructions stored in the computer readable storage medium are loaded and executed by the processor as follows:

[0181] A power system disaster accident risk index system is established according to the risk level of the disaster accident, and the development mode of the system cascading failure under the disaster scenario is refined by using the power system disaster accident risk index system; a cascading failure propagation model is established according to the cascading failure development mode caused by the natural disaster; island identification in the power system is performed based on the breadth-first search algorithm according to the cascading failure propagation model, the largest-size and highest-weight-coefficient subsystem is selected to form a new main system, and the cascading failure is continuously simulated; the power system cascading failure risk is evaluated according to the system data before and after the failure obtained by the cascading failure propagation model; the cascading failure mitigation strategy including a mitigation control cost model and a coordination control model is established according to the power system cascading failure risk, the synergistic mitigation strategy of the system cascading failure under the disaster condition is combined with the active preventive measures, and the potential cascading failure path is cut off after the disaster occurs.

[0182] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings 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 claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0183] The statistical data of past natural disasters and line faults in a certain region are used to evaluate the risk failure probability of actual overhead transmission lines. The transmission lines are operated under different weather conditions. The cascade failure simulation and the cascade failure mitigation strategy simulation are performed. The mitigation strategy model is solved by using the commonly used particle swarm optimization algorithm. The solution method is based on a double-layer decomposition optimization scheme, which selects the initial value of the prevention and control scheme and obtains the optimal solution of the blocking scheme under the given prevention and control scheme.

[0184] The main natural disasters in this region include rainstorm and flood, ice and snow, thunderstorm, gale, fire and earthquake. Table 1 lists the occurrence of overhead line trip caused by natural disasters in the past six consecutive years:

[0185] Table 1 Transmission line trip in the past 6 years

[0186]

[0187] The probability of overhead transmission line failure caused by different natural disasters is calculated, denoted as %, and the corresponding score and the operation risk R of the transmission line under the natural disaster are calculated by using a simplified formula. The results are shown in Table 2.

[0188] Table 2 Risk value of transmission line under natural disaster

[0189]

[0190] The natural disaster corresponding to the highest operation risk value, i.e. flood and rainstorm, has been selected as the target for evaluating the cascade failure of power system under disaster conditions. The evaluation results are shown in Figure 5 . Figure 5The ordinate represents the number of transmission lines that triggered cascading failures under natural disasters, while the abscissa represents the simulation results of the Indl index of the corresponding transmission lines that triggered cascading failures. A higher value indicates a greater probability of cascading failures on the line. The left purple column chart shows the simulation results of system cascading failures without natural disasters, while the right yellow column chart represents the simulation results of system cascading failures under rainstorm and flood disasters. From Figure 5 it can be seen that under normal conditions without natural disasters, there are only 16 potential cascading failure trigger points, while under rainstorm and flood disaster conditions, the number of potential cascading failure trigger points increases to 35, an increase rate of 219%. This shows that natural disasters can significantly increase the likelihood of cascading failures.

[0191] At the same time, under natural disaster conditions, the severity of cascading failures (Indl) also increases significantly. Taking branch 9 and branch 42 as examples, under normal conditions without disasters, the Indl of cascading failures triggered by these two trigger points are 0.093 and 0.036 respectively. After the occurrence of rainstorm and flood disasters, the Indl of cascading failures triggered by these two trigger points increase to 0.345 and 0.523 respectively, with risk indexes increasing by 371% and 1453% respectively. According to the data provided in the figure, the average outage consequences (IndR) of the system before and after the occurrence of natural disasters are 0.052 and 0.253 respectively, indicating that the risk of cascading failures of the entire system has increased significantly.

[0192] In order to compare the effectiveness of control strategies, new indicators are defined, namely the reduction of IndR (ΔIndR) and the reduction of E (ΔE). The unit cost of load shedding in the control process is set to 200 yuan / MW, h for 500,000. For the system mentioned above with the highest cascading failure risk, rainstorm and flood, a coordinated control model is developed and solved, and the specific details are shown in Table 3.

[0193] Table 3 Performance of different control strategies under rainstorm and flood

[0194]

[0195] Control strategy 1 is a purely preventive control method that excludes emergency mitigation intervention. Its control idea is to adjust the unit output before the failure occurs to optimize the power flow distribution, thereby reducing the probability of cascading failures. It reduces the control pressure after the cascading failure path is triggered by increasing the operating cost of the system in normal operation, thereby reducing the occurrence of line overload after failure. However, the preventive effect is limited, resulting in a small reduction in power interruption risk (ΔIndR), poor control performance, a small reduction in operating risk (ΔE), and a relatively low cost-effectiveness ratio.

[0196] Control strategy 2 is a purely emergency mitigation strategy, without any proactive preventative measures. Its approach is to immediately disconnect the load and quickly restore the overloaded line to normal operation after a fault occurs, thus controlling the fault's spread. Compared to control strategy 1, it demonstrates stronger control effectiveness and better economy. However, because this strategy only implements control after the cascading fault path is activated, post-fault line overload is more prevalent, leading to higher emergency mitigation costs and significant post-fault control pressure.

[0197] Control Strategy 3 represents a coordinated control approach that combines preventative control and emergency mitigation. On one hand, pre-fault preventative control reduces the probability of fault occurrence and mitigates line overload caused by cascading fault paths, thereby reducing post-fault control pressure and lowering post-fault emergency mitigation costs. On the other hand, post-fault emergency mitigation can alleviate conflicts between cascading fault paths, increase the reduction in power outage risk (ΔIndR), and enhance overall control effectiveness. Therefore, this strategy offers optimal control performance and the highest cost-effectiveness ratio.

[0198] In the prevention phase, by adjusting the output of generator sets to optimize power flow distribution, the operating pressure on the system is reduced, and the severity of potential power flow overloads caused by faults is mitigated in advance. The results of preventative control are as follows: Figure 6 As shown.

[0199] like Figure 6 As shown, the control strategy proposed in this invention can optimize and adjust the generator output according to the actual power grid operation and the risk level of the line under disaster scenarios, thereby reducing the risk of system cascading failures at a lower cost and pre-sharing some of the prevention and control pressure after a failure.

[0200] In summary, the present invention provides a method and system for mitigating cascading faults in power systems based on accident and disaster scenarios. This method effectively and successfully interrupts cascading faults after a natural disaster occurs, thereby minimizing the area affected by power outages and comprehensively enhancing the power system's ability to withstand risks.

[0201] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be realized in the form of hardware or software. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0202] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the related description of other embodiments.

[0203] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present application can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0204] In the embodiments provided by the present application, it should be understood that the disclosed devices / terminals and methods can be implemented by other ways. For example, the device / terminal embodiments described above are only schematic, and the division of the modules or units is only a logical function division, and there can be another division way in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection between each other can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0205] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0206] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0207] The integrated module / unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware, and the computer program can be stored in a computer-readable storage medium. The computer program can implement the steps of each method embodiment when executed by a processor. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms. The computer-readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the computer-readable medium can include or exclude contents according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0208] The present application is described with reference to flowcharts and / or block diagrams according to the methods, devices, and computer program products of embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The device that implements the functions specified in one flow or multiple flows and / or blocks Figure 1 The device that implements the functions specified in one flow or multiple flows and / or blocks

[0209] These computer program instructions can also be stored in a computer-readable storage medium that can guide the computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer-readable storage medium produce a manufactured product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1one or more processes and / or blocks Figure 1 the function specified in the one or more blocks.

[0210] These computer program instructions can also be loaded into computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate a computer implemented process, so that the instructions executed on the computer or other programmable data processing devices provide a process for implementing the flow Figure 1 one or more processes and / or blocks Figure 1 the function specified in the one or more blocks.

[0211] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A method for cascading failure mitigation in power systems based on the context of the incident disaster, characterized by, The method comprises the following steps: According to the risk level of disaster accidents, a power system disaster accident risk index system is established, and the development mode of system cascading failure under disaster scenarios is refined by using the power system disaster accident risk index system; According to the cascading failure development mode caused by natural disasters, a cascading failure propagation model is established; based on the breadth-first search algorithm, island identification in the power system is performed based on the cascading failure propagation model, and the largest size and highest weight coefficient subsystem is selected to form a new main system to continuously simulate cascading failure; In the cascading failure propagation model, when the generator set scheduling cannot meet the power balance demand, there are two scenarios: After a certain climbing period, if the output power of the generator is still greater than the system load value, the generator needs to be dropped according to the dropping priority of the generator to achieve power balance; If the system load continues to exceed the output power of the generator after the specified generator ramp period, the load shedding priority load assigned to each load is shed in accordance with the assigned load shedding priority coordinated load shedding measures; Islanding of power systems is identified based on a breadth-first search algorithm, and then the severity of the consequences is used The scale of power system outages caused by cascading failure events with complete fault paths is measured using the average outage consequences of power system cascading failures The risk of system cascading failures is measured; Generator node Drop precedence of the generator node Load shedding precedence of the load node Specifically: in, Indicates generator node The weight vector, Indicates generator node Power generation output, This represents the weight vector of the load node. Indicates the load level of the load node; Consequences severity And average outage consequences Respectively: wherein, is the initial set of system load nodes; denotes the set of load nodes in the final system; and denote the load of the access nodes before and after the failure, respectively; denotes the set of all branches in the system; denotes the number of elements in the set . The relief control cost model includes: System operational risk indicator is the sum of economic indicators and power outage risk indicators ; Economic index of coordinated control To prevent control cost And probability-weighted interruption mitigation control cost The sum; power outage risk index Indicates the total risk on all cascading failure paths; Preventive control cost And probability-weighted interruption mitigation control cost Respectively: wherein, represents the cascading path the preventive control cost after control; , , , respectively represent the active power of the generator before preventive control, the active power of the generator after preventive control, the adjustment coefficient of the active power of the cascading fault and the generator ; According to the system data before and after the failure obtained by the cascading failure propagation model, the cascading failure risk of the power system is evaluated; according to the cascading failure risk of the power system, a cascading failure mitigation strategy including the relief control cost model and the coordination control model is established, and the synergistic mitigation strategy of system cascading failure under disaster conditions is combined with active preventive measures to cut off the potential cascading failure path after the disaster occurs.

2. The method for mitigating cascading failures in power systems in the context of an incident disaster as claimed in claim 1, wherein, Overhead line disaster operation risk value is: wherein, denotes a natural disaster causing a probability of line failure; is a natural disaster causing a line failure damage value; denotes a natural disaster causing a loss of transmission capacity value due to line failure, is a natural disaster causing a social impact coefficient of line risk, denotes the total number of natural disasters.

3. The method for mitigating cascading failures in power system in the context of accident disaster as claimed in claim 1, wherein, Natural disaster The social impact factor of the line risk caused by Is: wherein, is a natural disaster causing a natural disaster risk period coefficient; represents a natural disaster risk weight.

4. The method for mitigating cascading failures in power systems in the context of an incident disaster as claimed in claim 1, wherein, The coordination control model includes: The goal of the coordination control model is to obtain a control scheme with the minimum operation risk under the given network topology and weather conditions, that is, to minimize the power outage risk with the minimum control cost, and the objective function is: The preventive control power balance maintenance constraint: The power balance maintenance constraint after emergency relief: The preventive control line flow constraint: The line flow constraint after emergency relief: The load limit adjustment constraint after emergency relief: The generator output limit constraint: in, For load nodes Loads after prevention and control; , , They represent Power flow after line-based preventive control, cascading fault paths After emergency relief Line power flow, Limits of line power current, , Indicates generator The upper and lower limits of active power output. Indicates cascading fault paths Load nodes during emergency mitigation The cutting load, Indicates the number of generators. Indicates the load quantity. This indicates a cascading failure path.

5. An incident disaster context based power system cascading failure mitigation system implementing the method of claim 1, characterized by, It includes: The index module, according to the risk level of disaster accidents, establishes a power system disaster accident risk index system, and refines the development mode of system cascading failure under disaster scenarios by using the power system disaster accident risk index system; The simulation module, according to the cascading failure development mode caused by natural disasters, establishes a cascading failure propagation model; based on the breadth-first search algorithm, island identification in the power system is performed based on the cascading failure propagation model, and the largest size and highest weight coefficient subsystem is selected to form a new main system to continuously simulate cascading failure; The output module, according to the system data before and after the failure obtained by the cascading failure propagation model, evaluates the cascading failure risk of the power system; According to the cascading failure risk of the power system, a cascading failure mitigation strategy including the relief control cost model and the coordination control model is established, and the synergistic mitigation strategy of system cascading failure under disaster conditions is combined with active preventive measures to cut off the potential cascading failure path after the disaster occurs.

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