Screening method and device for critical system state of power system, and storage medium

Abstract

The invention discloses a power system critical system state screening method and device, a storage medium and computer equipment, and the method comprises the steps: obtaining system parameters and system state spaces of a to-be-analyzed power system, and determining first-order and second-order failure system state spaces based on the system parameters; according to the first-order failure system state space, splitting to-be-freeze-frame from the Borger structure, and according to the first-order failure system state space and the second-order failure system state space, updating a critical system state set; determining a to-be-freeze-frame second-order failure system state space through a to-be-freeze-frame algorithm, updating the current critical system state set, after the process is finished, splitting the second-order failure system state space into a plurality of subsets according to elements in the to-be-freeze-frame first-order system state space, and splitting the to-be-freeze-frame based on each subset to obtain a splitting result; and when the splitting result does not meet the preset condition, determining a new to-be-freeze-frame, and determining a new splitting result until the splitting result meets the preset condition, thereby obtaining the critical system state of the to-be-analyzed power system.

Description

Technical Field

[0001] The present application relates to the technical field of power system reliability assessment, and in particular to a method and device for screening critical system states of a power system, a storage medium, and a computer device. Background Art

[0002] With the continued advancement of the "dual carbon" goals, the number of renewable energy devices such as wind and solar power in power systems has increased dramatically, causing power systems to become increasingly complex. In a power system, each component (which can be the aforementioned renewable energy devices such as wind and solar power, or components such as busbars) has two states: a normal component state and a failed component state (a failed component state indicates that the component has failed and can no longer function normally without intervention). Assigning each component a component state and combining the component states corresponding to different components together constitutes a system state of the power system. Combining the different system states of a power system together constitutes the system state space of the power system. Analyzing whether the power system fails under each system state in the system state space is crucial for studying the reliability of the power system. However, due to the large number of components in the current power system, the number of corresponding system states of the power system is huge, and the scale of the system state space of the power system is growing exponentially, posing a huge challenge to the assessment of the operational reliability of the power system.

[0003] In the prior art, when using the system state space to evaluate the reliability of the power system, either an enumeration method is used to analyze each system state in the system state space one by one, and finally find all normal system states or all failed system states; or a sampling is performed from the system state space according to the probability of occurrence of the system state, and the sampled system state is evaluated to determine whether the system state is a normal system state or a failed system state, and then the reliability of the power system is evaluated based on these system states. However, for the first method, since the system state space of the power system is huge, if the enumeration method is used to evaluate the system states one by one, not only a large amount of analysis cost is wasted, but also the analysis efficiency is low; for the second method, the probability of occurrence of high-order system states (i.e., system states in which a large number of components fail at the same time) is often low, resulting in high-order system states being difficult to sample. If the reliability of the power system is evaluated by the sampling method, the accuracy of the obtained reliability will eventually be low.

[0004] For power systems, critical system states exist within their state space. For a critical system state, repairing any component will ensure that the power system corresponding to the repaired state will not experience load shedding. Therefore, identifying critical system states within the power system state space is crucial for improving the efficiency of power system reliability assessments. Summary of the Invention

[0005] In view of this, the present application provides a method and device for screening critical system states of an electric power system, a storage medium, and a computer device. By continuously dividing the Boolean structure of the electric power system to be analyzed, a large number of high-order failure system states can be identified in the grid to be determined based on the second-order failure system state of the grid to be determined after each division. Then, the remaining unidentified system states are iteratively divided into grids and evaluated for the second-order failure system states. In each round of evaluation, a batch of failure system states can be identified, and all critical system states of the electric power system to be analyzed can also be found. Compared with the method of analyzing the operating state of the electric power system corresponding to the system state of the electric power system to be analyzed through flow calculation, the present application can greatly reduce the number of flow calculation evaluations, quickly determine all critical system states, and thus improve the efficiency of reliability evaluation of the electric power system to be analyzed.

[0006] According to one aspect of the present application, a method for screening a critical system state of a power system is provided, comprising:

[0007] Acquire system parameters and a system state space corresponding to the power system to be analyzed, and determine the first-order and second-order failure system state spaces of the power system to be analyzed from the system state space based on the system parameters;

[0008] According to the first-order failure system state space of the power system to be analyzed, a to-be-determined grid is split from a Boolean structure corresponding to the system state space, and according to the first-order and second-order failure system state spaces of the power system to be analyzed, a critical system state set is updated to obtain an updated critical system state set, wherein the to-be-determined grid contains at least one target system state, and the power system operation state corresponding to the target system state is an unknown state;

[0009] Invoking a pending grid algorithm, determining a second-order failure system state space of the pending grid by the pending grid algorithm, and updating a current critical system state set. After the update is completed, splitting the second-order failure system state space of the pending grid into a plurality of mutually non-overlapping subsets based on elements in the first-order system state space of the pending grid, and splitting the pending grid based on the second-order failure system states contained in each subset to obtain splitting results, wherein the number of second-order failure system states contained in each subset gradually decreases;

[0010] When the splitting result does not meet the preset conditions, a new pending grid is determined from the splitting result, and the pending grid algorithm is called again. The second-order failure system state space of the new pending grid is determined by the pending grid algorithm, and the current critical system state set is updated. After the update is completed, a new splitting result is determined, and the process ends when the splitting result meets the preset conditions. Each critical system state in the current critical system state set is used as the critical system state of the power system to be analyzed.

[0011] According to another aspect of the present application, a device for screening a critical system state of a power system is provided, comprising:

[0012] a data acquisition module, configured to acquire system parameters and a system state space corresponding to the power system to be analyzed, and determine the first-order and second-order failure system state spaces of the power system to be analyzed from the system state space based on the system parameters;

[0013] a set updating module, configured to split a pending grid from a Boolean structure corresponding to a first-order failure system state space of the power system to be analyzed, and to update a critical system state set according to the first-order and second-order failure system state spaces of the power system to be analyzed, thereby obtaining an updated critical system state set, wherein at least one target system state exists in the pending grid, and the power system operation state corresponding to the target system state is an unknown state;

[0014] an algorithm calling module, configured to call a pending grid algorithm, determine the second-order failure system state space of the pending grid by the pending grid algorithm, and update the current critical system state set; after the update is completed, split the second-order failure system state space of the pending grid into a plurality of mutually non-overlapping subsets based on the elements in the first-order system state space of the pending grid; split the pending grid based on the second-order failure system states contained in each subset to obtain a splitting result, wherein the number of second-order failure system states contained in each subset gradually decreases;

[0015] A loop module is used to determine a new pending grid from the splitting result when the splitting result does not meet the preset conditions, and call the pending grid algorithm again to determine the second-order failure system state space of the new pending grid through the pending grid algorithm, and update the current critical system state set. After the update is completed, a new splitting result is determined, and the process ends when the splitting result meets the preset conditions, and each critical system state in the current critical system state set is used as the critical system state of the power system to be analyzed.

[0016] According to another aspect of the present application, a storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the method for screening the critical system state of the power system is implemented.

[0017] According to another aspect of the present application, a computer device is provided, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor implements the above-mentioned method for screening critical system states of a power system when executing the program.

[0018] By means of the above technical solution, the present application provides a method and device for screening the critical system state of an electric power system, a storage medium, and a computer device. By continuously dividing the Boolean structure of the electric power system to be analyzed, a large number of high-order failure system states can be identified in the grid to be determined based on the second-order failure system state of the grid to be determined after each division. Then, the remaining unidentified system states are iteratively divided into grids and evaluated for the second-order failure system states. In each round of evaluation, a batch of failure system states can be identified, and all critical system states of the electric power system to be analyzed can also be found. Compared with the method of analyzing the operating state of the electric power system corresponding to the system state of the electric power system to be analyzed through flow calculation, the present application can greatly reduce the number of flow calculation evaluations, quickly determine all critical system states, and thus improve the efficiency of reliability evaluation of the electric power system to be analyzed.

[0019] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0021] Figure 1 A schematic flow chart of a method for screening a critical system state of a power system provided in an embodiment of the present application is shown;

[0022] Figure 2 A schematic diagram of a system state space of a fifth-order power system provided by an embodiment of the present application is shown;

[0023] Figure 3 A schematic diagram of the structure of a third-order Boolean grid provided in an embodiment of the present application is shown;

[0024] Figure 4A schematic diagram of the structure of a Boolean grid of [{1,3},{1,2,3,5,6}] provided in an embodiment of the present application is shown;

[0025] Figure 5 A schematic diagram showing a result of dividing a fifth-order power system into two parts according to the first-order system state is shown in an embodiment of the present application;

[0026] Figure 6 A schematic flow chart of a method for screening a critical system state of a power system provided in an embodiment of the present application is shown;

[0027] Figure 7 A schematic diagram of a processing flow of a pending grid algorithm provided in an embodiment of the present application is shown;

[0028] Figure 8 A schematic structural diagram of a device for screening critical system states of a power system provided in an embodiment of the present application is shown;

[0029] Figure 9 A schematic diagram of the device structure of a computer device provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0030] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0031] In this embodiment, a method for screening critical system states of a power system is provided, such as Figure 1 As shown, the method includes:

[0032] Step 101 : obtaining system parameters and a system state space corresponding to a power system to be analyzed, and determining first-order and second-order failure system state spaces of the power system to be analyzed from the system state space based on the system parameters.

[0033] The present application provides a method for screening critical system states of a power system, which can quickly screen out critical system states from the system state space of the power system to be analyzed, so that the failure system state space can be divided from the system state space based on these critical system states, thereby improving the efficiency of the reliability assessment of the power system. In fact, the system state space can be divided into a normal system state space and a failure system state space, wherein the normal system state space includes all system states that can make the power system operate in a normal state (that is, no load shedding occurs), and the failure system state space includes all system states that make the power system operate in a load shedding state. For any power system, it can include various components. Here, the components can be equipment in the power system, such as renewable energy equipment such as wind and light, generator equipment, etc.; the components can also be some assemblies in the power system, such as busbars, etc. For any component, its component state can include two types: a normal component state and a failure component state. In the normal component state, the component can operate normally; in the failure component state, the component stops working. The system state space of each power system to be analyzed can be determined as follows: determine the number of components in the power system to be analyzed, then assign each component a component state, and combine the component states corresponding to different components in the power system to be analyzed, thus forming a component state combination corresponding to the power system to be analyzed. Each component state combination is considered a system state, and the finite set of these system states can be called the system state space. In addition, for power systems, the following properties exist: if all components are normal, the power system operating state must be normal operation; if all components fail, the power system operating state must be load shedding; for a system state that causes load shedding in the power system, the failure of another component based on this system state will not restore the power system operating state to normal; for a system state that prevents load shedding in the power system, repairing another component based on this system state will not cause the power system operating state to return to load shedding.

[0034] First, the power system to be analyzed can be determined, and the system parameters and system state space corresponding to the power system to be analyzed can be obtained. Here, the system parameters can be various primitive parameters of the power system to be analyzed, such as line failure rate, rated current, and generator failure rate, power generation, and other primitive parameters. Then, based on the system parameters, the first-order and second-order failure system state spaces can be determined from the system state space of the power system to be analyzed. The first-order failure system state space only includes the first-order failure system states of the power system to be analyzed. A first-order failure system state refers to a system state in which only one component is in a failed state, while the remaining components are in a normal state, and the power system to be analyzed experiences load shedding. Similarly, the second-order failure system state space only includes the second-order failure system states of the power system to be analyzed. A second-order failure system state refers to a system state in which only two components are in a failed state, while the remaining components are in a normal state, and the power system to be analyzed experiences load shedding. In one embodiment, a target DC power flow equation and an optimal load shedding model for the power system to be analyzed can be constructed based on the system structure diagram and system parameters corresponding to the power system to be analyzed. The power system operating state corresponding to each first-order and second-order system state is then calculated based on the target DC power flow equation and the optimal load shedding model. A first-order system state refers to a system state in which only one component is in a failed state and the rest are in a normal state. A second-order system state refers to a system state in which only two components are in a failed state and the rest are in a normal state. This results in the first-order and second-order failure system state spaces for the power system to be analyzed. For example, if the power system operating state corresponding to a first-order system state is a load shedding state, then that first-order system state can be added to the first-order failure system state space.

[0035] Step 102: split a pending grid from the Boolean structure corresponding to the system state space according to the first-order failure system state space of the power system to be analyzed, and update the critical system state set according to the first-order and second-order failure system state spaces of the power system to be analyzed to obtain an updated critical system state set, wherein there is at least one target system state in the pending grid, and the power system operation state corresponding to the target system state is an unknown state.

[0036] In this embodiment, the Boolean structure corresponding to the system state space can then be split based on the first-order failure system state in the first-order failure system state space, and divided into multiple failure grids and a pending grid. Here, both the failure grid and the pending grid contain at least one system state, and the system state in the failure grid is a system state that causes the power system to be analyzed to shed load, while the pending grid contains at least one target system state, that is, the target system state is a system state that cannot be determined whether it causes the power system to be analyzed to shed load or operate normally. At the same time, based on the Boolean structure corresponding to the power system to be analyzed, it can be determined whether the first-order failure system state in the first-order failure system state space and the second-order failure system state in the second-order failure system state space are critical system states. If they are critical system states, the critical system state is added to the critical system state set. It should be noted that the critical system state set is initially an empty set.

[0037] The concept of critical system state is as follows: if the upper bound system state of a failure system state is all failure system state, and the lower bound system state is all normal system state, we call such a system state a critical system state. like Then s is the critical system state; a system state that is not a critical system state is called a non-critical system state, denoted as NCSS. Based on a critical system state, the system state resulting from any component with multiple faults will inevitably cause the power system to shed load, while the system state resulting from any component with fewer faults will inevitably cause the power system to operate normally.

[0038] The critical system state has the following characteristics: (1) If the upper bound system state of a system state s that makes the power system operating state in the normal operating state is the system state that makes the power system operating state in the load shedding state, then s is a critical system state; if the lower bound system state of a system state s that makes the power system operating state in the load shedding state is the system state that makes the power system operating state in the normal operating state, then s is a critical system state. (2) The first-order failure system state must be a critical system state, and the direct upper bound of the non-k-1 order failure element in the k-order failure system state must also be a critical system state. (3) The critical system state is in the transition layer between the power system operating state of the load shedding state and the working operation state, so it has strong dynamics and instability, and has great analytical significance in the system space.

[0039] According to the above characteristic (2), the k-order critical system state can be determined as follows:

[0040]

[0041] In particular,

[0042]

[0043] Figure 2 A schematic diagram of a system state space provided by an embodiment of the present application is shown. The power system to be analyzed includes a total of 5 elements. First, the system states in the system state space are grouped according to the order, and 6 groups are obtained, corresponding to the zero-order system state space to the fifth-order system state space. These groups (i.e., these rows) are sorted in descending order of order, that is, the group corresponding to the fifth-order system state space is placed at the top, and the group corresponding to the zero-order system state space is placed at the bottom, thus obtaining Figure 2 The schematic diagram shown.

[0044] Step 103: Call the pending grid algorithm, determine the second-order failure system state space of the pending grid by the pending grid algorithm, and update the current critical system state set. After the update is completed, split the second-order failure system state space of the pending grid into multiple non-intersecting subsets based on the elements in the first-order system state space of the pending grid, and split the pending grid based on the second-order failure system states contained in each subset to obtain a split result, wherein the number of second-order failure system states contained in each subset gradually decreases.

[0045] In this embodiment, after the grid to be determined is split out from the Boolean structure corresponding to the power system to be analyzed, the grid to be determined algorithm can be used to further analyze the grid to be determined. Specifically, the following analysis can be performed by the grid to be determined algorithm: first, the second-order failure system state space of the grid to be determined is determined. It should be noted that the second-order failure system state space here is relative to the grid to be determined, rather than relative to the power system to be analyzed. That is, the second-order failure system state space of the power system to be analyzed is different from the second-order failure system state space of the grid to be determined, and the second-order failure system state space of the grid to be determined can be determined using the same method as the method for determining the second-order failure system state space of the power system to be analyzed. While determining the second-order failure system state space of the grid to be determined, the current critical system state set can also be updated. Once the second-order failure system state space of the pending grid has been determined, that is, after the critical system state set of this round has been updated, the second-order failure system state space of the pending grid can be split into multiple non-intersecting subsets based on the elements in the first-order system state space of the pending grid (that is, each first-order system state of the pending grid), with the number of second-order failure system states contained in each subset gradually decreasing. Subsequently, based on the second-order failure system states contained in each subset, the pending grid is further split to obtain a split result. At this time, the split result can include the failed grid and the new pending grid, or only the failed grid.

[0046] Step 104: When the splitting result does not meet the preset conditions, a new pending grid is determined from the splitting result, and the pending grid algorithm is called again. The second-order failure system state space of the new pending grid is determined by the pending grid algorithm, and the current critical system state set is updated. After the update is completed, a new splitting result is determined, and the process ends when the splitting result meets the preset conditions, and each critical system state in the current critical system state set is used as the critical system state of the power system to be analyzed.

[0047] In this embodiment, after obtaining the splitting results, it is possible to determine whether the splitting results meet the preset conditions. If the preset conditions are not met, it indicates that there are new pending grids and further determination and analysis is required. In this case, the process returns to step 103 and calls the pending grid algorithm again to analyze the new pending grid. This process ends when the splitting results of the new pending grid meet the preset conditions. Each critical system state in the current critical system state set is used as the critical system state of the power system to be analyzed, thus obtaining all the critical system states of the power system to be analyzed.

[0048] By applying the technical solution of this embodiment, the Boolean structure of the power system to be analyzed is continuously divided. After each division, a large number of high-order failure system states can be identified in the grid to be determined based on the second-order failure system state of the grid to be determined. Then, the remaining system states that have not been identified are iteratively divided and the second-order failure system state evaluation is performed. In each round of evaluation, a batch of failure system states can be identified, and all critical system states of the power system to be analyzed can be found. Compared with the method of analyzing the power system operating state corresponding to the system state of the power system to be analyzed through power flow calculation, the present application can greatly reduce the number of power flow calculation evaluations, quickly determine all critical system states, and thus improve the reliability evaluation efficiency of the power system to be analyzed.

[0049] In an embodiment of the present application, optionally, before step 102, the method further includes: defining a partial order relationship between each system state contained in the system state space of the power system to be analyzed, and constructing a Boolean structure corresponding to the system state space according to the partial order relationship.

[0050] In this embodiment, a partial order relation is defined between each system state in the system state space of the power system to be analyzed, and then a Boolean structure corresponding to the power system to be analyzed can be constructed based on the defined partial order relation. Specifically, a natural partial order relation is defined in the system state space: if for any i = 1, 2, ... n, there is s m (i)≤s m+1 (i), then s m Less than or equal to s m+1 , denoted as sm ≤s m+1 . Where s represents the system state, i represents the number of components in the power system to be analyzed, and m represents the order of the system state. The order of the system state represents the number of failed component states contained in the system state. For example, if a system state contains 5 failed component states, then the system state can be called a fifth-order system state, and all the fifth-order system states can form a fifth-order system state space. In discrete mathematics, when the power system includes n components, the system state space S with a natural partial order forms an n-order Boolean Lattice, which is denoted as n ,≤>. In the n-order Boolean lattice, there is a relationship that the state of the upper layer system is greater than the state of the lower layer system. The structure of the 3-order Boolean lattice can be as follows Figure 3 As shown, Figure 3 Each system state in is the system state that defines the partial order relation.

[0051] In the embodiment of the present application, optionally, the step 102 of "splitting the pending grid from the Boolean structure corresponding to the system state space according to the first-order failure system state space of the power system to be analyzed" includes: splitting the pending grid from the Boolean structure corresponding to the system state space based on the following formula

[0052]

[0053]

[0054] t0=∨(W (1) );

[0055] Wherein, S represents the system state space of the power system to be analyzed, represents the first-order failure system state space of the power system to be analyzed, a k represents the kth first-order failure system state of the power system to be analyzed, f0 represents the number of first-order failure system states contained in the first-order failure system state space of the power system to be analyzed, represents the highest-order failure system state of the power system to be analyzed, represents the zero-order system state of the power system to be analyzed, W (1) represents the first-order normal system state space of the power system to be analyzed, and ∨ represents a multi-element logical union.

[0056] In this embodiment, according to the above partial order relation, the system state space of the power system to be analyzed has its maximum element and minimum element, which are respectively and ​That is, the maximum element is the system state in which all components in the power system being analyzed are in a failed state (the worst case scenario), and the minimum element is the system state in which all components are normal (the best case scenario). ∨ represents a multi-valued logical union. In logic and set theory, "multi-valued logical union" usually refers to the union of multiple sets. Specifically, if there are m sets A1, A2, ..., and Am, their multi-valued logical union is the set containing all elements in these sets. For example, if there are three sets: A1 = {1, 2}, A2 = {2, 3}, and A3 = {3, 4}, then the multi-valued logical union of these three sets is {1, 2, 3, 4}.

[0057] Any two system states with a partial order relationship in the system can generate a Boolean Lattice. For example, suppose the two system states s∈S, by The boolean generated by and s is:

[0058]

[0059] Where s is The smallest element of for In particular, S also forms an n-order Boolean grid, denoted as For example, the diagram of the Boolean [{1,3},{1,2,3,5,6}] is as follows Figure 4 shown.

[0060] In fact, the system state space S of the power system to be analyzed can be divided in three different ways.

[0061] First, by order: all system states of rank k constitute a subset of S, that is, the k-order system state space, denoted as S (k) :

[0062] S (k) ={s∈S|ρ(s)=k};

[0063] For example, a three-element power system can be divided into the following order:

[0064] S (0) ={φ};

[0065] S (1) ={{1},{2},{3}};

[0066] S (2) ={{1,2},{1,3},{2,3}};

[0067] S (3) ={1,2,3};

[0068] Second, division by power system operating status (normal operation / load shedding): Based on the structure function, the system state space can be divided into the following two non-intersecting sets.

[0069] W={s∈S|Φ(s)=0}, F={s∈S|Φ(s)=1}.

[0070] The structure function Φ:S→{0,1} on the system state space is defined, where the output of the structure function represents the operating state of the power system, that is,

[0071]

[0072] W represents the normal system state space, and F represents the failed system state space.

[0073] Third, according to the atomic division of the system: a is an atom of S if and only if The atomic set of S is

[0074]

[0075] In fact, A(S)=S (1) .

[0076] Let {a1,a2,...,a n} is the n first-order system states of system S, then the components corresponding to the first n-1 first-order system states are normal, and the set of system states corresponding to the components that fail to function in the i-th first-order system state is denoted as S ik ,

[0077] S i =[a i ,t i ];

[0078] where a i is the i-th first-order system state, S i The system state in is the system state of class i.

[0079] For example, a fifth-order power system S = [{},{1,2,3,4,5}], The first-order system state is a i ={i}, i=1,2,..,5, then S can be formed by combining 5 Booleans and the smallest element, that is,

[0080]

[0081] The division results are as follows Figure 5 shown.

[0082] For the Boolean structure of the system state space of the power system to be analyzed constructed according to the partial order relationship, the undetermined grid can be split from the Boolean structure according to the first-order failure system state in the first-order failure system state space of the power system to be analyzed in the above manner.

[0083] Rearrange the components so that but Among them F (1) represents the first-order failure system state space of the power system to be analyzed, All are invalid cells, s i represents the i-th first-order failure system state of the power system to be analyzed.

[0084] The original system state space S can be calculated based on F (1) Divided into f0 invalid grids and one pending grid The smallest element of is the smallest element of S, The first-order system state is given by W (1) Therefore, its zero-order and first-order system states are both normal system states, and the higher-order system states are not completely known. Such a lattice is called an undetermined lattice.

[0085] In an embodiment of the present application, optionally, the step 102 of "updating the critical system state set according to the first-order and second-order failure system state spaces of the power system to be analyzed to obtain an updated critical system state set" includes: for the first-order failure system state space of the power system to be analyzed, determining the upward covering set corresponding to the first-order failure system state from the system state space of the power system to be analyzed, and removing the upward covering set corresponding to each first-order failure system state from the second-order failure system state space of the power system to be analyzed to obtain an updated second-order failure system state space; adding each first-order failure system state in the first-order failure system state space of the power system to be analyzed and each second-order failure system state in the updated second-order failure system state space to the critical system state set to obtain an updated critical system state set.

[0086] In this example, let s, t∈S. If t≤s and there does not exist u∈S such that t≤u≤s, then s is said to be an upper bound of t, and t is said to be a lower bound of s, denoted by s>t, t<s. The greatest lower bound of s and t is the common lower bound v∈S of s and t, such that for every lower bound u of s and t, u≤v, denoted by s∨t. Correspondingly, s and t have a least upper bound, denoted by s∧t.

[0087] Define the structure function of the Boolean grid on the system state space: Given a Boolean grid Define mapping DL :P(L)→P(L), where the domain and range of the mapping are both P(L). have Where P(L) is the power set of L. Similarly, we can define The downward and upward covering sets of T in the lattice L are called D L (T) and U L (T). In particular, D S (T), U S (T) is D(T), U(T).

[0088] Assumption F (1) represents the first-order failure system state space of the power system to be analyzed, U(F (1) ) represents the upward covering set corresponding to the state space of the first-order failure system, F (2) represents the second-order failure system state space of the power system to be analyzed, then the updated second-order failure system state space can be expressed as F (2) =F (2) / U(F (1) ), the updated critical system state set can be expressed as F (1) ∪(F (2) / U(F (1) )).

[0089] In an embodiment of the present application, optionally, the step 103 of "determining the second-order failure system state space of the to-be-determined grid by the to-be-determined grid algorithm and updating the current critical system state set" includes: determining whether there is a target second-order system state of an undetermined power system operation state in the second-order system state space of the to-be-determined grid by the to-be-determined grid algorithm, and when there is a target second-order system state, for each target second-order system state, judging whether there is a system state smaller than the target second-order system state in the current critical system state set; if there is a system state smaller than the target second-order system state in the current critical system state set, adding the target second-order system state to the second-order failure system state set of the to-be-determined grid; if the current critical system state If there is no system state less than the target second-order system state in the system state set, the power system operation state corresponding to the target second-order system state is calculated based on the system parameters and the preset power flow calculation formula, and when the power system operation state is the load shedding state, the target second-order system state is added to the current critical system state set and the second-order failure system state set to be determined; when the power system operation state of each target second-order system state is determined, the second-order failure system state space to be determined is constructed based on the current second-order failure system state set to be determined and the second-order system state that has been determined as the failure system state before calling the algorithm to be determined, and the current critical system state set is used as the updated critical system state set.

[0090] In this embodiment, relative to the pending grid, the pending grid algorithm can be used to determine which second-order system states from the pending grid may cause load shedding in the power system to be analyzed, and the critical system state set can be updated accordingly. Specifically, first, the pending grid algorithm is used to search the second-order system state space of the pending grid for a target second-order system state with an undetermined power system operating state. It should be noted that the second-order failure system state space here refers to the second-order failure system state space relative to the pending grid, rather than the second-order failure system state space relative to the power system to be analyzed.

[0091] If there is a target second-order system state for an undetermined power system operating state, then the current critical system state set is checked to see if there is a system state that is less than the target second-order system state. The less than state here is determined relative to the partial order relation.

[0092] If there is a system state in the current critical system state set that is smaller than the target second-order system state, it means that the target second-order system state is a critical system state, so it is added to the set of second-order failure system states to be determined.

[0093] If there is no system state that is less than the target second-order system state, it is necessary to further determine the power system operating state corresponding to the target second-order system state. Specifically, a preset power flow calculation formula can be used to calculate the power system operating state corresponding to the target second-order system state based on the system parameters, and determine whether the state is a load shedding state. (1) If the power system operating state corresponding to the target second-order system state is a load shedding state, it can be added to the set of second-order failure system states to be determined, as well as the current critical system state set. (2) If the power system operating state corresponding to the target second-order system state is a normal operating state, it can be added to the set of second-order normal system states to be determined.

[0094] The above process can complete the entire process of processing a target second-order system state. The above method can be used to process each target second-order system state. When the power system operating state of each target second-order system state is determined, the final second-order failure system state space to be determined can be constructed based on the current set of second-order failure system states to be determined and the second-order system states that have been determined to be load shedding before calling the algorithm to be determined, and the current critical system state set can be used as the updated critical system state set.

[0095] The embodiment of the present application realizes rapid determination of the state space of the second-order failure system in the pending grid through the pending grid algorithm and the judgment of the operating status of the power system, which facilitates subsequent in-depth analysis.

[0096] In an embodiment of the present application, optionally, the step 103 of "splitting the second-order failure system state space of the to-be-determined grid into multiple non-intersecting subsets according to the elements in the first-order system state space of the to-be-determined grid" includes: for the to-be-determined grid with a partial order relationship, splitting the second-order failure system state space of the to-be-determined grid according to the elements in the first-order system state space of the to-be-determined grid to obtain multiple subsets, wherein the number of subsets is n-1, n represents the order corresponding to the to-be-determined grid, the second-order failure system states of the to-be-determined grid contained in each subset do not overlap, and the number of second-order failure system states contained in each subset is in a decreasing sequence.

[0097] In this embodiment, an appropriate component sequence can be selected to transform the state space L of the second-order failure system to be fixed L into (2) Split the first-order system state of L into n-1 mutually disjoint sets Make it a subset The number of elements in is a decreasing sequence, i.e. l i ≥l j ,right j. Among them, L (2)represents the state space of the second-order failure system of the lattice to be determined, and the first-order system states of L are the elements in the first-order system state space of the lattice to be determined. Since the lattice to be determined is obtained by splitting the Boolean structure with a partial order relation, the lattice to be determined is also a lattice with a partial order relation. Therefore, the second-order failure system states of the lattice to be determined contained in each subset obtained after splitting are non-overlapping.

[0098] In an embodiment of the present application, optionally, the "splitting the to-be-determined grid based on the second-order failure system state contained in each subset to obtain a splitting result" in step 103 includes: splitting the to-be-determined grid into multiple sub-grids according to each first-order system state in the first-order system state space corresponding to the to-be-determined grid, wherein each sub-grid includes a system state greater than the corresponding first-order system state; for each sub-grid, judging whether there is a target subset corresponding to the sub-grid in the multiple subsets; when there is a corresponding target subset for the sub-grid, splitting the sub-grid according to each element in the target subset to obtain a sub-splitting result, and determining a new to-be-determined grid according to the sub-splitting result; when there is no corresponding target subset for the sub-grid, taking the sub-grid as a new to-be-determined grid; and obtaining the splitting result based on the new to-be-determined grid corresponding to each sub-grid.

[0099] In this embodiment, after obtaining multiple subsets corresponding to the state space of the second-order failure system of the to-be-fixed grid, the to-be-fixed grid can be further deeply split according to these subsets. Specifically, the to-be-fixed grid can be split into multiple sub-grids by first-order system states in the state space of the first-order system of the to-be-fixed grid. Figure 5 Split method.

[0100] After the splitting is complete, for each subgrid, a target subset matching the subgrid is searched from multiple subsets. If all elements in a subset are included in the subgrid, then the subset is used as the target subset corresponding to the subgrid. If a subgrid has a corresponding target subset, it indicates that the first-order system states of the subgrid are all system states that cause the power system to be analyzed to shed load. At this point, the subgrid can be further split in the same manner as the Boolean structure corresponding to the power system to be analyzed in step 102, splitting it into multiple failed grids and a pending grid, to obtain the sub-splitting results corresponding to the subgrid. If a new pending grid exists in the sub-splitting results, the next round of splitting is directly performed.

[0101] If a sub-grid does not have a matching target subset, it means that the sub-grid itself is a pending grid and the next round of splitting is carried out directly.

[0102] Finally, the sub-splitting results of each sub-grid can be merged together to obtain the final splitting result of the pending grid. In the embodiment of the present application, for each pending grid, by traversing and evaluating its second-order system state, the grid is split according to the above rules. In each sub-grid obtained after the split, the second-order failure system state can cover a large number of high-order failure system states, and then the remaining uncovered system states are iteratively grid-divided and evaluated by power flow calculation. Each round of evaluation can cover a batch of failure system states, and at the same time, all critical system states can be found, thereby greatly improving the recognition efficiency of failure system states and critical system states.

[0103] In an embodiment of the present application, optionally, after step 103, the method further includes: determining the number of updates of the set of pending grids, and when a first value corresponding to the number of updates is greater than a second value corresponding to the number of elements in the power system to be analyzed, determining that the splitting result meets the preset conditions; or, judging whether there is a new pending grid in the splitting result, and when no new pending grid exists in the splitting result, determining that the splitting result meets the preset conditions.

[0104] In this embodiment, whether the splitting result meets the preset conditions can be judged in the following two ways: one is based on the comparison of the update times of the pending grid set and the number of components in the power system; the other is to check whether there is a new pending grid in the splitting result.

[0105] Among them, each time a new undetermined grid is obtained, the undetermined grid can be added to the undetermined grid set. The number of updates of the undetermined grid set refers to the number of times the new undetermined grid is placed in the undetermined grid set during the splitting process. The first value refers to the value of the actual number of updates of the undetermined grid set. For example, if the number of updates is P1, then the first value is P1; the second value refers to the value of the number of elements in the power system to be analyzed, that is, the second value corresponding to the order of the power system to be analyzed. For example, if the number of elements in the power system to be analyzed is P2, then the second value is P2. If the first value exceeds the second value, it means that the number of splits has reached the maximum, and it can be determined that the split result meets the preset conditions.

[0106] Furthermore, judgments can be made based on new pending grids. Specifically, the split results can be checked for new pending grids. This generally means determining whether the split process is thorough. If no new pending grids are found in the split results, this indicates that the split process was sufficiently thorough, and all system states have been identified as corresponding power system operating states. Therefore, if no new pending grids are found, the split results meet the preset conditions.

[0107] Furthermore, as a refinement and extension of the specific implementation of the above embodiment, in order to fully illustrate the specific implementation process of this embodiment, another method for screening the critical system state of the power system is provided, such as Figure 6 as well as Figure 7 As shown, the method includes:

[0108] Among them, such as Figure 6 As shown, for an n0-order power system to be analyzed, its system data (including system parameters) and system state space S are determined, and the power flow calculation program is initialized, the order N0 is preset, and N=1 is initialized.

[0109] First, according to the power flow calculation program and system parameters, the power system operation state corresponding to each first-order system state in the power system to be analyzed is calculated, that is, the ergodic evaluation S (1) , divide S according to step 102, determine the current CS (critical system state set), CS = F (1) If f0≠0, then update S to It is an n-f0 order undetermined grid, and its zero-order and first-order system states are both normal system states; if f0=0, that is, S (1) =W (1) , the zero-order and first-order S are both normal system states, so it itself is a pending grid and there is no need to update S.

[0110] After that, initialize the pending grid set X = {S}, that is, the updated S is used as the pending grid of the power system to be analyzed. Traverse all the pending grids in X, and for each pending grid L j Call the pending grid algorithm to get each L j The newly divided pending grids will form the pending grid set X (note that the new pending grid set does not include the previous batch of pending grids), and the updated CS can be obtained. The value of N is increased by one to obtain the updated N (representing the number of updates to the pending grid set X).

[0111] Determine whether X is an empty set or N ≥ N0. If X is empty or N ≥ N0, then terminate. Otherwise, re-invoke the pending grid algorithm to obtain a new pending grid set X and an updated CS until X is empty or N ≥ N0. At this point, output CS, which is the final critical system state set for the power system to be analyzed.

[0112] The process after calling the pending grid algorithm is as follows Figure 7 As shown, step 1, determine a pending grid Current critical system state set Step 2: For the undetermined grid L, if L (2)After all the system states in are evaluated, we get Go to step 5; otherwise go to step 3; Step 3, any s∈L (2) , if there is a subset of s in CS, then determine Go to step 2; if there is no subset of s in CS, evaluate s using power flow calculation; step 4, if s is the system state that makes the power system to be analyzed the power system operating state of load shedding, then CS = CS∪s, If s is in normal state, Go to step 2. Step 5, according to the Choose a suitable first-order system state order a1, a2, ..., a n ,get Divide and determine the new pending grid. It should be noted that here represents a subset of the state space of the second-order failure system of the to-be-determined lattice L, represents a subset of the state space of the second-order normal system of the lattice to be determined L.

[0113] The embodiments of the present application utilize DC power flow calculations to accurately determine the load shedding conditions of the system state. The partial order relationship is used to determine the load shedding conditions of most system states, demarcating the covered failure system states in the form of failure grids, eliminating the need for excessive power flow calculations to evaluate the system state. The resulting load shedding distribution across the entire space is capable of screening out complete critical system states. The embodiments of the present application analyze the entire system state space based on critical system states, efficiently and analytically obtaining reliability indicators such as LOLP (loss of load probability), which is of great significance to the operation and maintenance of power systems.

[0114] In addition, the prior art mentions that the critical system state can be obtained by traversing the system state step by step by enumeration method combined with comparison, and the load shedding state of the system state space can also be obtained, but this method is time-consuming and requires not only a large amount of flow calculations, but also a large amount of comparisons. Compared with the results of the screening method for the critical system state of the power system to be analyzed in the embodiment of the present application, the results are shown in Tables 1 and 2. Since the screening method for the critical system state of the power system to be analyzed in the embodiment of the present application utilizes the partial order relationship between the system states to divide the failure grid and only considers the second-order system state of the grid to be determined, the number of flow evaluations is greatly reduced, and the calculation cost is reduced.

[0115] Table 1. Comparison of IEEE-RBTS system results

[0116]

[0117] Table 2. Comparison of IEEE-RTS79 system results

[0118]

[0119] Further, as Figure 1 The specific implementation of the method, the embodiment of the present application provides a screening device for critical system status of a power system, such as Figure 8 As shown, the device includes:

[0120] a data acquisition module, configured to acquire system parameters and a system state space corresponding to the power system to be analyzed, and determine the first-order and second-order failure system state spaces of the power system to be analyzed from the system state space based on the system parameters;

[0121] a set updating module, configured to split a pending grid from a Boolean structure corresponding to a first-order failure system state space of the power system to be analyzed, and to update a critical system state set according to the first-order and second-order failure system state spaces of the power system to be analyzed, thereby obtaining an updated critical system state set, wherein at least one target system state exists in the pending grid, and the power system operation state corresponding to the target system state is an unknown state;

[0122] an algorithm calling module, configured to call a pending grid algorithm, determine the second-order failure system state space of the pending grid by the pending grid algorithm, and update the current critical system state set; after the update is completed, split the second-order failure system state space of the pending grid into a plurality of mutually non-overlapping subsets based on the elements in the first-order system state space of the pending grid; split the pending grid based on the second-order failure system states contained in each subset to obtain a splitting result, wherein the number of second-order failure system states contained in each subset gradually decreases;

[0123] A loop module is used to determine a new pending grid from the splitting result when the splitting result does not meet the preset conditions, and call the pending grid algorithm again to determine the second-order failure system state space of the new pending grid through the pending grid algorithm, and update the current critical system state set. After the update is completed, a new splitting result is determined, and the process ends when the splitting result meets the preset conditions, and each critical system state in the current critical system state set is used as the critical system state of the power system to be analyzed.

[0124] Optionally, the device further comprises a Boolean building module; the Boolean building module is configured to:

[0125] Before splitting the undetermined grid from the Boolean structure corresponding to the system state space, a partial order relationship is defined between the system states contained in the system state space of the power system to be analyzed, and the Boolean structure corresponding to the system state space is constructed according to the partial order relationship.

[0126] Optionally, the set updating module is configured to:

[0127] Based on the following formula, the undetermined grid is split from the Boolean structure corresponding to the system state space

[0128]

[0129]

[0130] t0=∨(W (1) );

[0131] Wherein, S represents the system state space of the power system to be analyzed, represents the first-order failure system state space of the power system to be analyzed, a k represents the kth first-order failure system state of the power system to be analyzed, f0 represents the number of first-order failure system states contained in the first-order failure system state space of the power system to be analyzed, represents the highest-order failure system state of the power system to be analyzed, represents the zero-order system state of the power system to be analyzed, W (1) represents the first-order normal system state space of the power system to be analyzed, and ∨ represents a multi-element logical union.

[0132] Optionally, the set updating module is configured to:

[0133] For the first-order failure system state space of the power system to be analyzed, determining an upward covering set corresponding to the first-order failure system state from the system state space of the power system to be analyzed, and removing the upward covering sets corresponding to each first-order failure system state from the second-order failure system state space of the power system to be analyzed, to obtain an updated second-order failure system state space;

[0134] Each first-order failure system state in the first-order failure system state space of the power system to be analyzed and each second-order failure system state in the updated second-order failure system state space are added to the critical system state set to obtain an updated critical system state set.

[0135] Optionally, the algorithm calling module is used to:

[0136] Determine, by using the pending grid algorithm, whether there is a target second-order system state with an undetermined power system operating state in the second-order system state space of the pending grid, and when there is a target second-order system state, determine, for each target second-order system state, whether there is a system state smaller than the target second-order system state in the current critical system state set;

[0137] If there is a system state smaller than the target second-order system state in the current critical system state set, then adding the target second-order system state to the second-order failure system state set to be determined;

[0138] If there is no system state less than the target second-order system state in the current critical system state set, then based on the system parameters, the power system operating state corresponding to the target second-order system state is calculated using a preset power flow calculation formula, and when the power system operating state is a load shedding state, the target second-order system state is added to the current critical system state set and the second-order failure system state set to be determined;

[0139] When the power system operating states of all target second-order system states are determined, the second-order failure system state space to be determined is constructed based on the current set of second-order failure system states to be determined and the second-order system states that have been determined as failure system states before calling the algorithm to be determined, and the current critical system state set is used as the updated critical system state set.

[0140] Optionally, the algorithm calling module is used to:

[0141] For the undetermined grid with a partial order relationship, the second-order failure system state space of the undetermined grid is split according to the elements in the first-order system state space of the undetermined grid to obtain multiple subsets, wherein the number of subsets is n-1, n represents the order corresponding to the undetermined grid, the second-order failure system states of the undetermined grid contained in each subset do not overlap, and the number of second-order failure system states contained in each subset is a decreasing sequence.

[0142] Optionally, the algorithm calling module is used to:

[0143] According to each first-order system state in the first-order system state space corresponding to the to-be-determined grid, the to-be-determined grid is split into a plurality of sub-grids, wherein each sub-grid includes a system state greater than the corresponding first-order system state;

[0144] For each sub-grid, determine whether there is a target subset corresponding to the sub-grid in the multiple subsets; if the sub-grid has a corresponding target subset, split the sub-grid according to each element in the target subset to obtain a sub-splitting result, and determine a new pending grid based on the sub-splitting result; if the sub-grid does not have a corresponding target subset, use the sub-grid as a new pending grid;

[0145] The splitting result is obtained based on the new pending grid corresponding to each sub-grid.

[0146] Optionally, the device further includes a judgment module; the judgment module is configured to:

[0147] After obtaining the splitting result, determining the update times of the pending grid set, and when a first value corresponding to the update times is greater than a second value corresponding to the number of elements in the power system to be analyzed, determining that the splitting result meets a preset condition; or

[0148] After the splitting result is obtained, it is determined whether there is a new undetermined grid in the splitting result. When there is no new undetermined grid in the splitting result, it is determined that the splitting result meets the preset condition.

[0149] It should be noted that for other corresponding descriptions of the functional units involved in the device for screening the critical system state of a power system provided in the embodiment of the present application, reference can be made to Figures 1 to 7 The corresponding description in the method will not be repeated here.

[0150] The present application also provides a computer device, which can be a personal computer, a server, a network device, etc. Figure 9 As shown, the computer device includes a bus, a processor, a memory, and a communication interface, and may also include an input / output interface and a display device. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store location information. The network interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, the steps of each method embodiment are implemented.

[0151] Those skilled in the art will understand that Figure 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0152] In one embodiment, a computer-readable storage medium is provided. The computer-readable storage medium may be non-volatile or volatile, and stores a computer program thereon. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0153] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0154] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0155] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, and the like.

[0156] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0157] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for screening critical system states of a power system, characterized in that: include: Acquire system parameters and a system state space corresponding to the power system to be analyzed, and determine the first-order and second-order failure system state spaces of the power system to be analyzed from the system state space based on the system parameters; According to the first-order failure system state space of the power system to be analyzed, a to-be-determined grid is split from a Boolean structure corresponding to the system state space, and according to the first-order and second-order failure system state spaces of the power system to be analyzed, a critical system state set is updated to obtain an updated critical system state set, wherein the to-be-determined grid contains at least one target system state, and the power system operation state corresponding to the target system state is an unknown state; Invoking a pending grid algorithm, determining a second-order failure system state space of the pending grid by the pending grid algorithm, and updating a current critical system state set. After the update is completed, splitting the second-order failure system state space of the pending grid into a plurality of mutually non-overlapping subsets based on elements in the first-order system state space of the pending grid, and splitting the pending grid based on the second-order failure system states contained in each subset to obtain splitting results, wherein the number of second-order failure system states contained in each subset gradually decreases; When the splitting result does not meet the preset conditions, a new pending grid is determined from the splitting result, and the pending grid algorithm is called again. The second-order failure system state space of the new pending grid is determined by the pending grid algorithm, and the current critical system state set is updated. After the update is completed, a new splitting result is determined, and the process ends when the splitting result meets the preset conditions. Each critical system state in the current critical system state set is used as the critical system state of the power system to be analyzed.

2. The method according to claim 1, characterized in that Before separating the undetermined grid from the Boolean structure corresponding to the system state space, the method further includes: A partial order relationship is defined between each system state contained in the system state space of the power system to be analyzed, and a Boolean structure corresponding to the system state space is constructed according to the partial order relationship.

3. The method according to claim 2, characterized in that The step of splitting a pending grid from a Boolean structure corresponding to the first-order failure system state space of the power system to be analyzed comprises: Based on the following formula, the undetermined grid is split from the Boolean structure corresponding to the system state space t0=∨(W (1) ); Wherein, S represents the system state space of the power system to be analyzed, represents the first-order failure system state space of the power system to be analyzed, a k represents the kth first-order failure system state of the power system to be analyzed, f0 represents the number of first-order failure system states contained in the first-order failure system state space of the power system to be analyzed, represents the highest-order failure system state of the power system to be analyzed, represents the zero-order system state of the power system to be analyzed, W (1) represents the first-order normal system state space of the power system to be analyzed, and ∨ represents a multi-element logical union.

4. The method according to claim 2 or 3, characterized in that The updating of the critical system state set according to the first-order and second-order failure system state spaces of the power system to be analyzed to obtain an updated critical system state set includes: For the first-order failure system state space of the power system to be analyzed, determining an upward covering set corresponding to the first-order failure system state from the system state space of the power system to be analyzed, and removing the upward covering sets corresponding to each first-order failure system state from the second-order failure system state space of the power system to be analyzed, to obtain an updated second-order failure system state space; Each first-order failure system state in the first-order failure system state space of the power system to be analyzed and each second-order failure system state in the updated second-order failure system state space are added to the critical system state set to obtain an updated critical system state set.

5. The method according to claim 2, characterized in that The determining of the state space of the second-order failure system of the pending grid by the pending grid algorithm and updating the current critical system state set includes: Determine, by using the pending grid algorithm, whether there is a target second-order system state with an undetermined power system operating state in the second-order system state space of the pending grid, and when there is a target second-order system state, determine, for each target second-order system state, whether there is a system state smaller than the target second-order system state in the current critical system state set; If there is a system state smaller than the target second-order system state in the current critical system state set, then adding the target second-order system state to the second-order failure system state set to be determined; If there is no system state less than the target second-order system state in the current critical system state set, then based on the system parameters, the power system operating state corresponding to the target second-order system state is calculated using a preset power flow calculation formula, and when the power system operating state is a load shedding state, the target second-order system state is added to the current critical system state set and the second-order failure system state set to be determined; When the power system operating states of all target second-order system states are determined, the second-order failure system state space to be determined is constructed based on the current set of second-order failure system states to be determined and the second-order system states that have been determined as failure system states before calling the algorithm to be determined, and the current critical system state set is used as the updated critical system state set.

6. The method according to claim 2, characterized in that The step of splitting the state space of the second-order failure system to be determined into a plurality of mutually non-overlapping subsets according to the elements in the state space of the first-order system to be determined comprises: For the undetermined lattice with a partial order relationship, the second-order failure system state space of the undetermined lattice is split according to the elements in the first-order system state space of the undetermined lattice to obtain multiple subsets, wherein the number of the subsets is n-1, n represents the order corresponding to the undetermined lattice, the second-order failure system states of the undetermined lattice contained in each subset do not overlap, and the number of the second-order failure system states contained in each subset is in a decreasing sequence; Accordingly, based on the second-order failure system states contained in each subset, the undetermined grid is split to obtain split results, including: According to each first-order system state in the first-order system state space corresponding to the to-be-determined grid, the to-be-determined grid is split into a plurality of sub-grids, wherein each sub-grid includes a system state greater than the corresponding first-order system state; For each sub-grid, determine whether there is a target subset corresponding to the sub-grid in the multiple subsets; if the sub-grid has a corresponding target subset, split the sub-grid according to each element in the target subset to obtain a sub-splitting result, and determine a new pending grid based on the sub-splitting result; if the sub-grid does not have a corresponding target subset, use the sub-grid as a new pending grid; The splitting result is obtained based on the new pending grid corresponding to each sub-grid.

7. The method according to claim 1, characterized in that After obtaining the splitting result, the method further includes: Determine the number of updates of the set of pending grids, and when a first value corresponding to the number of updates is greater than a second value corresponding to the number of elements in the power system to be analyzed, determine that the splitting result meets the preset conditions; or, judge whether there is a new pending grid in the splitting result, and when no new pending grid exists in the splitting result, determine that the splitting result meets the preset conditions.

8. A device for screening critical system states of an electric power system, characterized in that: include: a data acquisition module, configured to acquire system parameters and a system state space corresponding to the power system to be analyzed, and determine the first-order and second-order failure system state spaces of the power system to be analyzed from the system state space based on the system parameters; a set updating module, configured to split a pending grid from a Boolean structure corresponding to a first-order failure system state space of the power system to be analyzed, and to update a critical system state set according to the first-order and second-order failure system state spaces of the power system to be analyzed, thereby obtaining an updated critical system state set, wherein at least one target system state exists in the pending grid, and the power system operation state corresponding to the target system state is an unknown state; an algorithm calling module, configured to call a pending grid algorithm, determine the second-order failure system state space of the pending grid by the pending grid algorithm, and update the current critical system state set; after the update is completed, split the second-order failure system state space of the pending grid into a plurality of mutually non-overlapping subsets based on the elements in the first-order system state space of the pending grid; split the pending grid based on the second-order failure system states contained in each subset to obtain a splitting result, wherein the number of second-order failure system states contained in each subset gradually decreases; A loop module is used to determine a new pending grid from the splitting result when the splitting result does not meet the preset conditions, and call the pending grid algorithm again to determine the second-order failure system state space of the new pending grid through the pending grid algorithm, and update the current critical system state set. After the update is completed, a new splitting result is determined, and the process ends when the splitting result meets the preset conditions, and each critical system state in the current critical system state set is used as the critical system state of the power system to be analyzed.

9. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

10. A computer device comprising a storage medium, a processor, and a computer program stored in the storage medium and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

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