A method and device for searching and analyzing static safety critical sections of a transmission network

Abstract

A method and device for searching and analyzing static safety critical sections of a transmission network, relating to the technical field of power system safety, wherein the method selects a transmission network that needs to search for thermal stability critical sections, and constructs a set variable representation for the transmission network; reflects the set associations within the transmission network through the set variable representation; constructs a thermal stability critical section search model according to the set variable representation, and sets set constraints for the thermal stability critical section search model; solves the thermal stability critical section search model to obtain the thermal stability critical section of the transmission network. The present invention can consider the collective characteristics of the cut set section and the line thermal stability margin to search for the thermal stability critical section of the transmission network, proposes a thermal stability critical section search method from an optimization perspective, and implements a critical section search based on mixed integer programming.

Description

Technical Field

[0001] The present invention relates to the technical field of power system safety, and in particular to a method and device for searching and analyzing static safety critical sections of a transmission network. Background Art

[0002] In the field of power system security, with the access of renewable energy, the output variations in some areas of the power system have increased and the randomness has increased, resulting in increasingly prominent problems in system thermal stability.

[0003] At present, in the actual power system, the number of nodes and lines is increasing, and the risk scenarios in the system are increasing accordingly. According to the identification results, relevant regulation of key sections can greatly improve the calculation efficiency and ensure the safe and stable operation of the power system.

[0004] Therefore, it is of great significance to identify the key links of the transmission network under different operating modes. Under massive operating modes, how to quickly and accurately identify the key power transmission sections, how to linearize the characteristics of the cut-set sections and the thermal stability margin of the lines have become urgent problems to be solved. Summary of the invention

[0005] To this end, the present invention provides a method and device for searching and analyzing static safety critical sections of a transmission network, which can consider the collective characteristics of cut set sections and the thermal stability margin of the line to search for thermal stability critical sections of the transmission network, propose a thermal stability critical section search method from an optimization perspective, and realize critical section search based on mixed integer programming.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a method for searching and analyzing static safety critical sections of a transmission network, comprising:

[0007] A transmission network for which a thermal stability critical section search is required is selected, and a set variable representation is constructed for the transmission network, wherein the set variable representation includes: a power flow variable representation, a virtual flow variable representation, and a section selection indicator variable representation; and the set association situation in the transmission network is reflected by the set variable representation;

[0008] constructing a thermal stability critical section search model according to the set variable representation, and setting set constraints for the thermal stability critical section search model;

[0009] The thermal stability critical section search model is solved to obtain the thermal stability critical section of the transmission network.

[0010] As a preferred solution for a static safety critical section search and analysis method of a transmission network, the power flow variables include branch ij The current of the branch ij Current limitation; pay attention to the specific section of the line ijThermal stability safety margin, if the line ij It is a critical section for thermal stability, which is equal to the branch ij The current margin of the node is 0 otherwise. i The voltage amplitude of the node j The voltage amplitude of the branch ij Active current of branch ij Reactive power flow; node j Power generation on the node j Load power on the branch jk Active current of branch jk Reactive power flow; branch lj Active current of branch lj Reactive power flow; node i The collection of all child nodes of a node; i The set of all parent nodes of ;

[0011] The virtual flow variable includes a branch ij Virtual flow passing through, used for connectivity within area numbered 0; branch ij The virtual flow passing through is used for the connectivity inside the area numbered 1;

[0012] The section selection indicator variables include branch ij Whether it is a thermal stability critical section; node i Located in the area, 0 represents the power sending end area, 1 represents the power receiving end area; node i Whether to use it as the starting node for connectivity constraint search.

[0013] As a preferred scheme for a transmission network static safety-critical section search and analysis method, in the process of using the set variables to represent the set association conditions within the transmission network, the flow variable represents the system flow relationship of the transmission network; the virtual flow variable represents the internal connectivity of the transmission network; and the section selection indicator variable represents the section search result of the transmission network.

[0014] As a preferred solution of a transmission network static safety critical section search and analysis method, the objective function of the thermal stability critical section search model is to minimize the section thermal stability margin, and the expression of the objective function is:

[0015] ;

[0016] In the formula, For a specific section of interest, the line ij Thermal stability safety margin; E A specific cross-sectional area of ​​interest.

[0017] As a preferred solution for a method for searching and analyzing static safety critical sections of a transmission network, the set constraints set for the thermal stability critical section search model include: cut set graph theory characteristic constraints of the section, connectivity constraints of the virtual flow, and power flow constraints based on cone optimization.

[0018] The present invention also provides a transmission network static safety critical section search and analysis device, based on the above transmission network static safety critical section search and analysis method, comprising:

[0019] A variable representation construction module is used to select a transmission network that needs to be searched for a thermal stability critical section, and to construct a set variable representation for the transmission network, wherein the set variable representation includes: a power flow variable representation, a virtual flow variable representation, and a section selection indicator variable representation; and the set association situation in the transmission network is reflected by the set variable representation;

[0020] A thermal stability critical section search model construction module is used to construct a thermal stability critical section search model according to the set variable representation, and set set constraints for the thermal stability critical section search model;

[0021] The thermal stability critical section search model solving module is used to solve the thermal stability critical section search model to obtain the thermal stability critical section of the transmission network.

[0022] As a preferred solution of a transmission network static safety critical section search and analysis device, the variable represents a building module, the flow variable includes a branch ij The current of the branch ij Current limitation; pay attention to the specific section of the line ij Thermal stability safety margin, if the line ij It is a critical section for thermal stability, which is equal to the branch ij The current margin of the node is 0 otherwise. i The voltage amplitude of the node j The voltage amplitude of the branch ij Active current of branch ij Reactive power flow; node j Power generation on the node j Load power on the branch jk Active current of branch jk Reactive power flow; branch lj Active current of branch lj Reactive power flow; node i The collection of all child nodes of a node; i The set of all parent nodes of ;

[0023] The virtual flow variable includes a branch ij Virtual flow passing through, used for connectivity within area numbered 0; branchij The virtual flow passing through is used for the connectivity inside the area numbered 1;

[0024] The section selection indicator variables include branch ij Whether it is a thermal stability critical section; node i Located in the area, 0 represents the power sending end area, 1 represents the power receiving end area; node i Whether to use it as the starting node for connectivity constraint search.

[0025] As a preferred solution for a transmission network static safety-critical section search and analysis device, in the variable representation construction module, in the process of reflecting the set association situation within the transmission network through the set variable representation, the flow variable representation reflects the system flow relationship of the transmission network; the virtual flow variable representation reflects the internal connectivity of the transmission network; and the section selection indicator variable representation reflects the section search result of the transmission network.

[0026] As a preferred solution of a transmission network static safety critical section search and analysis device, in the thermal stability critical section search model construction module, the objective function of the thermal stability critical section search model is to minimize the section thermal stability margin, and the expression of the objective function is:

[0027] ;

[0028] In the formula, For a specific section of interest, the line ij Thermal stability safety margin; E A specific cross-sectional area of ​​interest.

[0029] As a preferred solution for a transmission network static safety critical section search and analysis device, in the thermal stability critical section search model construction module, the set constraints set for the thermal stability critical section search model include: cut set graph theory characteristic constraints of the section, connectivity constraints of the virtual flow, and power flow constraints based on cone optimization.

[0030] The present invention has the following advantages: selecting a transmission network that needs to search for a thermal stability critical section, and constructing a set variable representation for the transmission network, the set variable representation includes: a power flow variable representation, a virtual flow variable representation and a section selection indicator variable representation; the set variable representation reflects the set association situation in the transmission network; in the process of reflecting the set association situation in the transmission network through the set variable representation, the power flow variable representation reflects the system power flow relationship of the transmission network; the virtual flow variable representation reflects the internal connectivity of the transmission network; the section selection indicator variable representation reflects the section search result of the transmission network. A thermal stability critical section search model is constructed according to the set variable representation, and set constraints are set for the thermal stability critical section search model; the thermal stability critical section search model is solved to obtain the thermal stability critical section of the transmission network. The present invention simultaneously considers the topological structure and power flow of the power system, and searches for the thermal stability vulnerable link of the power system to ensure the safe and reliable operation of the power system; the present invention uses an analytical mathematical model to describe the search process and mechanism of the thermal stability critical section of the transmission network, so that the problem can be combined with other optimization problems to achieve the overall solution of more complex and comprehensive problems. The present invention considers the collective characteristics of the cut set sections and the thermal stability margin of the line to search for the key thermal stability sections of the transmission network, proposes a method for searching the key thermal stability sections from an optimization perspective, and realizes the key section search based on mixed integer programming. The present invention simultaneously considers the topological structure and power flow of the power system, and searches for the thermal stability vulnerable links of the power system to ensure the safe and reliable operation of the power system; the present invention uses an analytical mathematical model to describe the search process and mechanism of the key thermal stability sections of the transmission network, so that the problem can be combined with other optimization problems to achieve an overall solution to more complex and comprehensive problems. The present invention can realize the rapid identification of the key power transmission sections of the system in a large number of scenarios in the actual power system, and provide an effective reference for the screening and identification of key scenarios and the adjustment of system strategies. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0032] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0033] Figure 1 A schematic diagram of a flow chart of a method for searching and analyzing a static safety critical section of a transmission network provided in Embodiment 1 of the present invention;

[0034] Figure 2 A schematic diagram of a thermal stability critical section of an IEEE39 node system under normal operation in a possible embodiment provided in Embodiment 1 of the present invention;

[0035] Figure 3 A schematic diagram of a critical section of thermal stability when a fault occurs in line 2-3 of an IEEE39 node system in a possible embodiment provided in Embodiment 1 of the present invention;

[0036] Figure 4 A schematic diagram of branch margin values ​​of an IEEE39 node system in a normal state in a possible embodiment provided in Embodiment 1 of the present invention;

[0037] Figure 5 A schematic diagram of branch margin value under line 2-3 fault of IEEE39 node system in a possible embodiment provided in embodiment 1 of the present invention;

[0038] Figure 6 This is a schematic diagram of the architecture of a transmission network static safety critical section search and analysis device provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0039] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] See also Figure 1 Embodiment 1 of the present invention provides a method for searching and analyzing a static safety critical section of a power transmission network, comprising the following steps:

[0042] S1. Select a transmission network that needs to search for a thermal stability critical section, and construct a set variable representation for the transmission network, wherein the set variable representation includes: a power flow variable representation, a virtual flow variable representation, and a section selection indicator variable representation; and the set association situation in the transmission network is reflected by the set variable representation;

[0043] S2. constructing a thermal stability critical section search model according to the set variable representation, and setting set constraints for the thermal stability critical section search model;

[0044] S3. Solve the thermal stability critical section search model to obtain the thermal stability critical section of the transmission network.

[0045] In this embodiment, in step S1, a transmission network for which a thermal stability critical section search is required is selected, and a set variable representation is constructed for the transmission network, wherein the set variable representation includes: a power flow variable representation, a virtual flow variable representation, and a section selection indicator variable representation; the set association situation in the transmission network is reflected by the set variable representation;

[0046] Among them, the power flow variable represents the system power flow relationship of the transmission network; the virtual flow variable represents the internal connectivity of the transmission network; and the section selection indicator variable represents the section search result of the transmission network.

[0047] Specific:

[0048] Establish a power grid flow variable representation, the power flow variables include: Indicates branch ij The current; Indicates branch ij Current limitation; Indicates the line of reference for a specific section ij Thermal stability safety margin, if the line ij It is a critical section for thermal stability, which is equal to the branch ij The current margin is 0 otherwise; Representation Node i The voltage amplitude; Representation Node j The voltage amplitude; Indicates branch ij The meritorious trend; Indicates branch ij Reactive power flow; For Node j The power generation on For Node j The load power on Indicates branch jk The meritorious trend; Indicates branch jk Reactive power flow; Indicates branch lj The meritorious trend; Indicates branch lj Reactive power flow; Representation Node i The set of all child nodes of ; Representation Node i The set of all parent nodes of ;

[0049] A virtual flow variable representation is established, wherein the virtual flow variable includes: Indicates branch ij The virtual flow passing through is used for the connectivity inside the area numbered 0; Indicates branch ij The virtual flow passing through is used for the connectivity inside the area numbered 1;

[0050] Establishing a section selection indicator variable representation, the section selection indicator variable includes: It is a 0-1 variable, indicating a branch ij Whether it is a thermal stability critical section, if yes, the value is 1, otherwise, the value is 0; It is a 0-1 variable, indicating a node i In which area, 0 indicates the power sending area, and 1 indicates the power receiving area; It is a 0-1 variable, indicating a node i Whether it is the starting node of the connection constraint search. If yes, the value is 1, otherwise it is 0.

[0051] In this embodiment, in step S2, a thermal stability critical section search model is constructed according to the set variable representation, and set constraints are set for the thermal stability critical section search model;

[0052] Specifically, the objective function of the thermal stability critical section search model is to minimize the thermal stability margin of the section, and the expression of the objective function is:

[0053] ;

[0054] In the formula, For a specific section of interest, the line ij Thermal stability safety margin; E A specific cross-sectional area of ​​interest.

[0055] In this embodiment, the set constraints set for the thermal stability critical section search model include: cut set graph theory feature constraints of the section, connectivity constraints of the virtual flow, and power flow constraints based on cone optimization.

[0056] Specifically, the expression of the cut set graph theory feature constraint of the cross section is shown in equations (1)-(6):

[0057] ;

[0058] ;

[0059] in,

[0060] Formula (1) shows that the line not included in the section ij , whose two end nodes are located in the same partition;

[0061] Formula (2) shows that the line included in the section ij , whose two end nodes are located in different partitions;

[0062] Formula (3) shows that the transmission direction of cross-section tidal current is consistent;

[0063] Formulas (4) and (5) show that if the line ij It is a thermally stable critical section. Equal to branch ij The current margin is 0 otherwise;

[0064] Formula (6) shows that the section contains at least one branch.

[0065] The expressions of the connectivity constraints of virtual flows are shown in equations (7) to (12):

[0066] ;

[0067] in,

[0068] Formulas (7)-(9) are the internal connectivity constraints for the region numbered 0; Formula (7) represents the circulation constraint of the virtual flow; Formula (8) represents the node virtual flow balance constraint; Formula (9) indicates that there can only be one source of virtual flow in the network;

[0069] Formulas (10)-(12) are the internal connectivity constraints for the region numbered 1; Formula (10) represents the circulation constraint of the virtual flow; Formula (11) represents the node virtual flow balance constraint; Formula (12) indicates that there can only be one source of virtual flow in the network.

[0070] The expressions of power flow constraints based on cone optimization are shown in equations (13)-(16):

[0071] ;

[0072] in,

[0073] Formula (13) represents the line power flow equation;

[0074] Formula (14) establishes the relationship constraint between voltage, current and power flow;

[0075] Formula (15) represents the active power balance constraint of each node;

[0076] Equation (16) represents the reactive power balance constraint of each node.

[0077] In this embodiment, in step S3, the thermal stability critical section search model is solved to obtain the thermal stability critical section of the transmission network.

[0078] Specifically, by solving the thermal stability critical section search model of step S2, the thermal stability critical section of the system can be obtained. For possible expected fault scenarios, the above model is solved under the corresponding fault topology to obtain the critical section set under the expected fault.

[0079] In a possible embodiment, an example of solving the critical section of thermal stability of the system using an IEEE 39-node system is provided as follows:

[0080] T1. Establish flow variables, virtual flow variables and section selection indicator variables for the IEEE 39-node system to reflect the system flow relationship, system internal connectivity and section search results;

[0081] T2. Establishing a thermal stability critical section search model according to established tidal flow variables, virtual flow variables and section selection indicator variables, and setting constraints for the thermal stability critical section search model;

[0082] T3. Obtain the thermal stability critical section of the transmission network by solving the thermal stability critical section search model.

[0083] In the IEEE 39-bus system, 46 lines are calculated and the corresponding branch margin values ​​are obtained under the relevant constraints. The calculation results of the 46 lines are as follows: Figure 4 As shown. Figure 4 It can be seen that the margin values ​​of the 9th, 13th, and 26th branches are relatively large, corresponding to the 4-14, 16-17, and 6-11 lines of the IEEE39 power saving system. Based on the above calculation, the key cross-section diagram of the system under normal conditions is obtained as follows Figure 2 shown.

[0084] Assuming that the expected fault is a fault on line 2-3, the calculation results of the margin values ​​of 45 branches under the corresponding fault state are as follows: Figure 5 As shown. Figure 5 It can be seen that the margin values ​​of the 7th, 22nd and 41st branches are relatively large, corresponding to the 4-5, 13-14 and 26-27 lines of the IEEE 39 power saving system. Based on the above calculation, the key cross-section diagram of the system under normal conditions is obtained as follows: Figure 3 shown.

[0085] In summary, the present invention selects a transmission network that needs to search for a thermal stability critical section, and constructs a set variable representation for the transmission network, the set variable representation includes: a flow variable representation, a virtual flow variable representation and a section selection indicator variable representation; the set variable representation reflects the set association situation in the transmission network; in the process of reflecting the set association situation in the transmission network through the set variable representation, the flow variable representation reflects the system flow relationship of the transmission network; the virtual flow variable representation reflects the internal connectivity of the transmission network; the section selection indicator variable representation reflects the section search results of the transmission network. A thermal stability critical section search model is constructed according to the set variable representation, and set constraints are set for the thermal stability critical section search model; the thermal stability critical section search model is solved to obtain the thermal stability critical section of the transmission network. The present invention simultaneously considers the topological structure and flow of the power system, and searches for the thermal stability vulnerable link of the power system to ensure the safe and reliable operation of the power system; the present invention uses an analytical mathematical model to describe the search process and mechanism of the thermal stability critical section of the transmission network, so that this problem can be combined with other optimization problems to achieve an overall solution to more complex and comprehensive problems. The present invention considers the collective characteristics of the cut set sections and the thermal stability margin of the line to search for the key thermal stability sections of the transmission network, proposes a method for searching the key thermal stability sections from an optimization perspective, and realizes the key section search based on mixed integer programming. The present invention simultaneously considers the topological structure and power flow of the power system, and searches for the thermal stability vulnerable links of the power system to ensure the safe and reliable operation of the power system; the present invention uses an analytical mathematical model to describe the search process and mechanism of the key thermal stability sections of the transmission network, so that the problem can be combined with other optimization problems to achieve an overall solution to more complex and comprehensive problems. The present invention can realize the rapid identification of the key power transmission sections of the system in a large number of scenarios in the actual power system, and provide an effective reference for the screening and identification of key scenarios and the adjustment of system strategies.

[0086] It should be noted that the method of the embodiment of the present disclosure can be performed by a single device, such as a computer or a server. The method of the present embodiment can also be applied in a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present disclosure, and the multiple devices will interact with each other to complete the described method.

[0087] It should be noted that the above describes some embodiments of the present disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0088] Example 2

[0089] See also Figure 6 Embodiment 2 of the present invention further provides a transmission network static safety critical section search and analysis device, comprising:

[0090] The variable representation construction module 001 is used to select a transmission network that needs to search for a thermal stability critical section, and construct a set variable representation for the transmission network, wherein the set variable representation includes: a power flow variable representation, a virtual flow variable representation, and a section selection indicator variable representation; the set association situation in the transmission network is reflected by the set variable representation;

[0091] A thermal stability critical section search model construction module 002 is used to construct a thermal stability critical section search model according to the set variable representation, and set set constraints for the thermal stability critical section search model;

[0092] The thermal stability critical section search model solving module 003 is used to solve the thermal stability critical section search model to obtain the thermal stability critical section of the transmission network.

[0093] In this embodiment, the variables represent the construction module 001, and the power flow variables include the branch ij The current of the branch ij Current limitation; pay attention to the specific section of the line ij Thermal stability safety margin, if the line ij It is a critical section for thermal stability, which is equal to the branch ij The current margin of the node is 0 otherwise. i The voltage amplitude of the node j The voltage amplitude of the branch ij Active current of branch ij Reactive power flow; node j Power generation on the node j Load power on the branch jk Active current of branch jk Reactive power flow; branch lj Active current of branch lj Reactive power flow; node iThe collection of all child nodes of a node; i The set of all parent nodes of ;

[0094] The virtual flow variable includes a branch ij Virtual flow passing through, used for connectivity within area numbered 0; branch ij The virtual flow passing through is used for the connectivity inside the area numbered 1;

[0095] The section selection indicator variables include branch ij Whether it is a thermal stability critical section; node i Located in the area, 0 represents the power sending end area, 1 represents the power receiving end area; node i Whether to use it as the starting node for connectivity constraint search.

[0096] In this embodiment, in the variable representation construction module 001, in the process of reflecting the set association situation within the transmission network through the set variable representation, the flow variable representation reflects the system flow relationship of the transmission network; the virtual flow variable representation reflects the internal connectivity of the transmission network; the section selection indicator variable representation reflects the section search result of the transmission network.

[0097] In this embodiment, in the thermal stability critical section search model construction module 002, the objective function of the thermal stability critical section search model is to minimize the thermal stability margin of the section, and the expression of the objective function is:

[0098] ;

[0099] In the formula, For a specific section of interest, the line ij Thermal stability safety margin; E A specific cross-sectional area of ​​interest.

[0100] In this embodiment, in the thermal stability critical section search model construction module 002, the set constraints set for the thermal stability critical section search model include: cut set graph theory feature constraints of the section, connectivity constraints of the virtual flow and power flow constraints based on cone optimization.

[0101] It should be noted that the information interaction, execution process and other contents between the modules of the above-mentioned system are based on the same concept as the method embodiment in Example 1 of the present application, and the technical effects they bring are the same as those of the method embodiment of the present application. For specific contents, please refer to the description in the method embodiment shown above in the present application, and will not be repeated here.

[0102] Example 3

[0103] Embodiment 3 of the present invention provides a non-transitory computer-readable storage medium, in which a program code for a method for searching and analyzing a static safety critical section of a transmission network is stored. The program code includes instructions for executing embodiment 1 or any possible implementation method of a method for searching and analyzing a static safety critical section of a transmission network.

[0104] Computer-readable storage media can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0105] Example 4

[0106] Embodiment 4 of the present invention provides an electronic device, including: a memory and a processor;

[0107] The processor and the memory communicate with each other via a bus; the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute a method for searching and analyzing static safety critical sections of a power transmission network in accordance with embodiment 1 or any possible implementation thereof.

[0108] Specifically, the processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor implemented by reading software codes stored in a memory. The memory can be integrated in the processor or can be located outside the processor and exist independently.

[0109] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable systems. The computer instructions can be stored in a computer-readable storage medium, or transmitted from a computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center.

[0110] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing system, they can be concentrated on a single computing system, or distributed on a network composed of multiple computing systems, and optionally, they can be implemented by a program code executable by a computing system, so that they can be stored in a storage system and executed by the computing system, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0111] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for searching and analyzing static safety critical sections of a transmission network, characterized in that: include: A transmission network for which a thermal stability critical section search is required is selected, and a set variable representation is constructed for the transmission network, wherein the set variable representation includes: a power flow variable representation, a virtual flow variable representation, and a section selection indicator variable representation; and the set association situation in the transmission network is reflected by the set variable representation; constructing a thermal stability critical section search model according to the set variable representation, and setting set constraints for the thermal stability critical section search model; Solving the thermal stability critical section search model to obtain the thermal stability critical section of the transmission network; The flow variables include the current of branch ij; the current limit of branch ij; the thermal stability safety margin of line ij in the sense of the specific section of interest, if line ij belongs to the thermal stability critical section, it is equal to the current margin of branch ij, otherwise it is 0; the voltage amplitude of node i; the voltage amplitude of node j; the active power flow of branch ij; the reactive power flow of branch ij; the generated power on node j; the load power on node j; the active power flow of branch jk; the reactive power flow of branch jk; the active power flow of branch lj; the reactive power flow of branch lj; the set of all child nodes of node i; the set of all parent nodes of node i; The virtual flow variables include: It represents the virtual flow through branch ij, which is used for the connectivity within the area numbered 0; It represents the virtual flow through branch ij, which is used for the connectivity within the area numbered 1; The cross-section selection indicator variables include: C ij is a 0-1 variable, indicating whether the branch ij belongs to the thermal stability critical section. If yes, it takes the value 1, otherwise it takes the value 0; γ i is a 0-1 variable, indicating the region where node i is located, 0 represents the power sending region, and 1 represents the power receiving region; β i is a 0-1 variable, indicating whether node i is the starting node of the connectivity constraint search. If yes, it takes the value 1, otherwise it takes the value 0; In the process of reflecting the setting association situation in the transmission network through the setting variables, the flow variable represents the system flow relationship of the transmission network; the virtual flow variable represents the internal connectivity of the transmission network; the section selection indicator variable represents the section search result of the transmission network; The objective function of the thermal stability critical section search model is to minimize the thermal stability margin of the section. The expression of the objective function is: In the formula, α ij is the thermal stability safety margin of line ij in the sense of the specific section of concern; E is the specific section area of ​​concern.

2. A method for searching and analyzing static safety critical sections of a power transmission network according to claim 1, characterized in that: The set constraints set for the thermal stability critical section search model include: cut set graph theory characteristic constraints of the section, connectivity constraints of the virtual flow and power flow constraints based on cone optimization.

3. A transmission network static safety critical section search and analysis device, using a transmission network static safety critical section search and analysis method according to any one of claims 1-2, characterized in that: include: A variable representation construction module is used to select a transmission network that needs to be searched for a thermal stability critical section, and to construct a set variable representation for the transmission network, wherein the set variable representation includes: a power flow variable representation, a virtual flow variable representation, and a section selection indicator variable representation; and the set association situation in the transmission network is reflected by the set variable representation; A thermal stability critical section search model construction module is used to construct a thermal stability critical section search model according to the set variable representation, and set set constraints for the thermal stability critical section search model; A thermal stability critical section search model solving module, used for solving the thermal stability critical section search model to obtain the thermal stability critical section of the transmission network; The variable represents the building block, and the flow variables include the current of branch ij; the current limit of branch ij; the thermal stability safety margin of line ij in the sense of the specific section of interest, if line ij belongs to the thermal stability critical section, it is equal to the current margin of branch ij, otherwise it is 0; the voltage amplitude of node i; the voltage amplitude of node j; the active power flow of branch ij; the reactive power flow of branch ij; the generated power on node j; the load power on node j; the active power flow of branch jk; the reactive power flow of branch jk; the active power flow of branch lj; the reactive power flow of branch lj; the set of all child nodes of node i; the set of all parent nodes of node i; The virtual flow variables include: It represents the virtual flow through branch ij, which is used for the connectivity within the area numbered 0; It represents the virtual flow through branch ij, which is used for the connectivity within the area numbered 1; The cross-section selection indicator variables include: C ij is a 0-1 variable, indicating whether the branch ij belongs to the thermal stability critical section. If yes, it takes the value 1, otherwise it takes the value 0; γ i is a 0-1 variable, indicating the region where node i is located, 0 represents the power sending region, and 1 represents the power receiving region; β i is a 0-1 variable, indicating whether node i is the starting node of the connectivity constraint search. If yes, it takes the value 1, otherwise it takes the value 0; In the variable representation construction module, in the process of reflecting the setting association situation in the transmission network through the setting variable representation, the flow variable representation reflects the system flow relationship of the transmission network; the virtual flow variable representation reflects the internal connectivity of the transmission network; the section selection indicator variable representation reflects the section search result of the transmission network; In the thermal stability critical section search model construction module, the objective function of the thermal stability critical section search model is to minimize the thermal stability margin of the section, and the expression of the objective function is: In the formula, α ij is the thermal stability safety margin of line ij in the sense of the specific section of concern; E is the specific section area of ​​concern.

4. A transmission network static safety critical section search and analysis device according to claim 3, characterized in that: In the thermal stability critical section search model construction module, the set constraints set for the thermal stability critical section search model include: cut set graph theory feature constraints of the section, connectivity constraints of the virtual flow and power flow constraints based on cone optimization.

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