WO2020015625A1

WO2020015625A1 - Power system vulnerability assessment method and terminal device

Info

Publication number: WO2020015625A1
Application number: PCT/CN2019/096120
Authority: WO
Inventors: 袁博; 吴希明; 葛贤军; 王涛; 邵华; 王颖; 张倩茅; 张章; 陈亮; 江轶; 刘雪飞; 荆志朋; 张丽洁; 习朋; 王凯; 凌云鹏; 唐帅; 赵建华
Original assignee: 国网河北省电力有限公司经济技术研究院; 中能电（北京）科技有限公司
Priority date: 2018-07-16
Filing date: 2019-07-16
Publication date: 2020-01-23
Also published as: CN109066650A; CN109066650B

Abstract

The present application provides a power system vulnerability assessment method and a terminal device. The method comprises: determining an average transmission electrical distance of a power system after line fault according to the weight and electrical length of all transmission paths after each line fault and the total amount of active power transmitted; determining a local voltage variation of the power system after the line fault according to voltages of a target load node after and before the line fault; determining a local reactive power variation of the power system after the line fault according to reactive power outputs of a target generator node after and before the line fault, and the reactive power capacity of the target generator node; determining a reliability variation of the power system after the line fault according to reliability indexes of all load nodes after and before the line fault; determining the vulnerability of the line according to the average transmission electrical distance, the local voltage variation, the local reactive power variation and the reliability variation; and locating the weakness of the power system according to the vulnerability of each line.

Description

Vulnerability assessment method of power system and terminal equipment

This application claims priority from a Chinese patent application filed with the Chinese Patent Office on July 16, 2018, with application number 201810778095.8, the entire contents of which are incorporated herein by reference.

Technical field

The present application belongs to the technical field of power systems, and for example, relates to a power system vulnerability assessment method and terminal equipment.

Background technique

As the scale of the power system increases, the grid will be highly interconnected through the main grid, the structure and operation of the grid will become increasingly complex, and the development model of the grid will also be affected. The highly interconnected power grid structure conforms to the basic characteristics of complex networks, and also brings certain security and stability risks to power systems. The power grids in many countries in the world have been proven to be typical complex networks. Therefore, using complex network theory for power system analysis becomes an effective tool.

The origin of complex network theory can be traced back to the stochastic graph theory. With the establishment of small-world network models and scale-free network models, complex network theory has been formally born and has become a research hotspot in many fields. Complex network theory indicates that there are a small number of lines in the power system that are critical to the network structure. These line failures often have a huge impact on the power system and even cause chain failures. This is also one of the root causes of hidden dangers in modern power systems with complex network characteristics. These few important lines that are important to the power system network structure and may cause cascading failures are called fragile lines in the power system. Therefore, the use of complex network theory to assess the vulnerability of power, and then to locate the weak links in the power system through fragile lines, is of great significance to optimize the structure of the power grid, eliminate potential risks, and ensure the safety and stability of the power system.

The vulnerability assessment of power systems is essentially the application and optimization of complex networks. First, the abstract topology model of the power system is established; then, the properties of the nodes and edges in the network are examined from a statistical perspective. The main characteristic indicators are the degree and degree distribution of the nodes, the average path length, the network clustering coefficient, the node number, and the edge number. Number etc. These characteristic indicators can reflect the structural characteristics of the actual network from multiple sides, and determine the vulnerability of various lines in the power system. Although this idea is simple to implement and excavates the structural characteristics of the power grid, in the analysis of the power system, the electrical characteristics of the topological connection and the physical meaning in actual operation are ignored. First, there is no impact caused by line faults; second, there is no consideration of factors such as active power flow, voltage changes, and reliability indicators. This leads to the fact that the evaluation results do not truly reflect the reality.

Summary of the invention

The embodiments of the present application provide a power system vulnerability assessment method and terminal equipment, which solve the problems of vulnerability assessment in the related technology that ignore the electrical characteristics of the topological connection and the physical significance in actual operation, and effectively complete the power system vulnerability assessment, and Locate weak links in power systems based on fragile lines.

An embodiment of the present application provides a power system vulnerability assessment method, including:

Determine the average transmission electrical distance of the power system after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure in the power system, and the total amount of active power transmitted; The voltage of the target load node after each line failure and the voltage of the target load node before each line failure are determined, and the local voltage change amount of the power system after each line failure is determined, wherein the target The load node is a load node whose voltage change after each line failure exceeds a preset voltage threshold; based on the reactive power output of the target generator node after each line failure and the target power generation before each line failure The reactive power output of the generator node and the reactive power capacity of the target generator node determine the local reactive power change of the power system after each line failure, wherein the target generator node is after the line failure Generator nodes with an increase in reactive power output exceeding a preset multiple of the generator node's own reactive capacity; The reliability index of the load node and the reliability index of all load nodes before the failure of each line determine the reliability change of the power system after the failure of each line; according to the failure of each line Determining the vulnerability of each line according to the subsequent average transmission electrical distance, the local voltage change amount, the local reactive power change amount, and the reliability change amount; Describe the weak links in the power system.

An embodiment of the present application further provides a power system vulnerability assessment device, including:

The average transmission electrical distance determining unit is configured to determine the power after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure in the power system, and the total amount of active power transmitted. The average transmission electrical distance of the system; the local voltage change determination unit is configured to determine each line according to the voltage of the target load node after each line failure and the voltage of the target load node before each failure The local voltage change amount of the power system after the fault, wherein the target load node is a load node whose voltage change amount after the line fault exceeds a preset voltage threshold; the local reactive power change amount determination unit is set according to each of the The reactive power output of the target generator node after the line failure and the reactive power output of the target generator node before each line failure, and the reactive power capacity of the target generator node determine the local reactive power of the power system. The amount of change in power, wherein the target generator node increases the reactive power output after the line fault exceeds itself Generator node with a preset multiple of reactive power; the reliability change determination unit is set according to the reliability index of all load nodes after each line failure and the reliability of all load nodes before each line failure Performance index to determine the reliability change of the power system after each line failure; the vulnerability determination unit is configured to be based on the average transmission electrical distance and the local voltage change amount after each line failure And the local reactive power change amount and the reliability change amount determine the vulnerability of each line; the system weak link positioning unit is configured to locate the weak link of the power system according to the vulnerability of each line.

An embodiment of the present application further provides a power system vulnerability assessment terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer The program implements the method described above.

An embodiment of the present application further provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, implements the foregoing method.

The embodiments of the present application solve the problem of lack of vulnerability assessment in the related technology to consider the electrical characteristics and the physical significance of the actual operation of the power system. From the three aspects of branch, electrical path, and power system parameter changes, the power system reliability assessment, components Its own characteristics and the influence of components on system operation are used in the vulnerability assessment. Not only the importance of branches and electrical paths in the topology connection relationship is considered, but also the impact on the power system operation caused by line failures. The results of the line vulnerability assessment in the system are comprehensive and can reflect the real problems of the actual power system. At the same time, the fragile lines of the power system are analyzed to improve the reliability level, which can further guide the later upgrade and transformation of the power grid and apply it to the grid planning and operation stages. .

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic flowchart of a power system vulnerability assessment method according to an embodiment of the present application; FIG.

2 is a schematic block diagram of a power system vulnerability assessment device according to an embodiment of the present application;

3 is a schematic block diagram of a power system vulnerability assessment device according to another embodiment of the present application;

FIG. 4 is a schematic block diagram of a power system vulnerability assessment terminal device according to an embodiment of the present application.

detailed description

In order to explain the technical solution described in this application, specific examples are used for description below.

Referring to FIG. 1, FIG. 1 is a schematic flowchart of a power system vulnerability assessment method according to an embodiment of the present application. In this embodiment, an angle trigger of a terminal is used as an example for description. As shown in FIG. 1, in this embodiment, the terminal processing process of the power system vulnerability assessment method may include the following steps:

S1010: Determine the average transmission electrical distance of the power system after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure of the power system, and the total amount of active power transmitted.

In an embodiment, before S1010, the method may further include: determining a total number of lines M in the power system, and numbering all lines, and the numbering variable l = 1, 2, 3, ... M.

In this embodiment, the weights and electrical lengths are active transmission power and reactance values of a transmission path, respectively.

In this embodiment, the average transmission electrical distance of the power system after a line failure is the quotient of the weighted electrical length of all transmission paths and the total active power transmitted by the power system, where the weighted length and d of all transmission paths are defined as all The sum of the product of the weight of the transmission path and the electrical length. In this embodiment, the active transmission power is used as the weight, and the reactance value is used as the electrical distance. In the power system, a transmission path can be formed between each generator node and each load node, that is, each transmission path starts with the generator node and ends with the load node. The generator node is a node that points to the power system to inject power, and the load node is a node that draws power from the power system. In some power systems, in addition to the generator nodes and load nodes, there are intermediate nodes (neither absorbing power nor injecting power). The generator node generally provides active power to multiple loads. The load node generally absorbs active power from multiple generator nodes. The electrical distances and active transmission power of the multiple sides experienced in the transmission path are different. The weighted electrical of the transmission path is different. It is difficult to uniquely determine the distance. To avoid this difficulty, the weighted electrical length sum of the transmission path is converted to the weighted electrical length sum of the line, which is derived as follows:

Among them, the subscript a refers to any transmission path, the subscript t refers to any line, t (a) refers to all the lines through which the transmission path a passes, and a (t) refers to all the transmission paths through the line t. p _a and p _t refer to the active power transmitted on transmission path a and the active power transmitted on line t; len _a and len _t refer to the electrical length of transmission path a and the active power transmitted on line t; w _r w _a and w _t Refers to the weight of path a and line t, respectively, and is represented by p _a and p _t .

In one embodiment, according to the expression

Determine the average transmission electrical distance D _l of the power system after line l failure, where d _l represents the sum of the weighted electrical lengths of all lines in the power system after line l failure, and w _t represents the weight of line t in power system after line l failure , Expressed by the active transmission power of line t, that is, w _t = p _t (p _t represents the active power transmitted by line t), len _t represents the electrical length of line t, that is, the reactance value of line t, and T (l) represents the The set of all the lines of the power system after the line 1 fault, P _n represents the active power absorbed by the node n after the line 1 fault, and N refers to the set of all nodes of the power system.

S1020: Determine the local voltage change amount of the power system after each line failure according to the voltage of the target load node after each line failure and the voltage of the target load node before each line failure. The target load node is a load node whose voltage change after a line fault exceeds a preset voltage threshold.

In this embodiment, the preset voltage threshold can be set according to actual needs. For example, after the line 1 fails, the voltage of the load node s drops more than α ₁ , the load node is considered to be significantly affected, and the load node is the target load node. The absolute value of the voltage difference between the load node s after the fault and the line 1 before the fault. Based on the absolute value of the voltage difference between the load nodes s calculated, the local voltage change of the power system after the fault of the line 1 is determined.

In one embodiment, according to the expression

Determine the local voltage variation V _l of the power system after the line 1 fault, where U _s and U _s0 represent the voltage of the target load node s after the line 1 fault and the voltage of the target load node s before the line 1 fault, S (l) Represents the set of target load nodes in the power system after a line 1 failure, wherein the target load node in the set of target load nodes has a voltage change amount after the line 1 failure exceeds a preset voltage threshold α ₁ , that is, S (l) = {s || U _s -U _s0 |> α ₁ }.

In this embodiment, the preset voltage threshold α ₁ should be determined according to an actual situation.

S1030: determine the target generator node's reactive power output after each line failure and the target generator node's reactive power output before each line failure, and the target generator node's reactive power capacity to determine the The local reactive power change of the power system after each line fault, wherein the target generator node is a generator node whose reactive power increase after each line fault exceeds a preset multiple of the reactive capacity of the generator node itself . In this embodiment, the preset multiple may be set according to actual needs. For example, after the line l fails, the reactive power increase of the generator node g exceeds ₂ times the reactive capacity of the generator node g. Affected significantly, the ratio of the reactive power output of generator node g to the reactive capacity of generator node g after line 1 failure and before line 1 failure is calculated. Based on this ratio, the local reactive power system failure after line 1 failure Work change.

In one embodiment, according to the expression

Determine the local reactive power change QQ _l of the power system after line 1 fault, where Q _g and Q _g0 represent the reactive power output of target generator node g after line 1 failure and the target generator node g before line 1 failure, respectively. Power output, Q _gmax represents the reactive power capacity of the target generator node g, and G (l) represents the target generator node set affected by the fault of line l, where the target generator node in the target generator node set is on the line l The increase of reactive power output after a fault exceeds the preset reactive power α _{2 of the} generator node itself, that is, G (l) = {g | (Q _g -Q _g0 ) / Q _gmax > α ₂ }.

In this embodiment, the preset multiple α _{2 of the} reactive capacity should be determined according to the actual situation.

S1040: Determine the reliability of the power system after each line failure according to the reliability indicators of all load nodes in the power system after each line failure and the reliability indicators of all load nodes before each line failure. Sexual change. In this embodiment, the difference between the reliability index of the load node after the line 1 failure and the line 1 before the failure is calculated, and the reliability change amount of the power system after the line 1 failure is determined according to the difference. The reliability index of the load node here can be measured by the node load loss probability caused by the line failure. The load loss probability can be obtained through the conventional reliability evaluation algorithm and the load loss time statistics. The above nodes are all load nodes in the power system after a line failure.

In one embodiment, according to the expression

Determine the reliability change RR _l of the power system after line 1 failure, where R _n and R _n0 represent the reliability index of load node n after line 1 failure and the reliability index of load node n before line 1 failure, NL indicates A set of all load nodes of the power system.

In an embodiment, the reliability index of node n is determined by the expression R _n = 1-PL _n , and PLn represents the load loss probability index of the load node n, that is, the probability value of the power supply of the node n is less than its load. The conventional reliability evaluation algorithm and statistics of the load loss time are obtained, that is, the ratio of the load load time n of the load node n to the total time is calculated to obtain the index.

S1050: Determine the vulnerability of each line according to the average transmission electrical distance, the local voltage change amount, the local reactive power change amount, and the reliability change amount after each line failure.

In an embodiment, the calculation is based on the reliability of line 1, that is, the probability of normal operation of the line, and the average transmission electrical distance, local voltage change, local reactive power change, and reliability change of the power system after the failure of line 1. The vulnerability of line l.

In one embodiment, according to the expression

Determine the vulnerability IV _{l of} line l, where rel (l) represents the reliability of line l, that is, the probability that line l works normally, obtained through historical statistics,

Represents the average transmission electrical distance of the power system after a normalized line l failure, by the expression

determine,

Represents the local voltage change of the power system after a normalized line l failure, through an expression

determine,

Represents the local reactive power change of the power system after a normalized line l failure, through the expression

determine,

Represents the normalized line l power system reliability change after a fault

determine,

with

Represent normalized index values of D _l , V _l , QQ _l and RR _l , and M represents the total number of lines in the power system.

S1060: Locate the weak link of the power system according to the vulnerability of each line.

Sort according to the vulnerability of all lines. The more vulnerable lines are more vulnerable, and the weak links of the power system are located according to the more vulnerable lines.

As can be seen from the above description, the power system vulnerability assessment method of the present application solves the problems of the lack of vulnerability assessment in the related technology to consider the electrical characteristics and the physical significance of the actual operation of the power system. There are three changes from branch roads, electrical paths, and power system parameters. In terms of power system reliability assessment, component characteristics, and the impact of components on system operation, not only the importance of branches and electrical paths in the topology connection relationship, but also the line failure The impact on the operation of the power system makes the results of line vulnerability assessment in the power system comprehensive and can reflect the real problems of the actual power system. At the same time, it analyzes the vulnerable lines of the power system and improves the reliability level, which can further guide the later stages of the power grid. Upgrading and transformation, applied to the grid planning and operation phase.

In addition, in an embodiment, the power system vulnerability assessment method further includes: in a case where the power system generates multiple connected subnets after the failure of each line, determining a maximum of the generated multiple connected subnets. The connected subnet; determining the average transmission electrical distance of the power system after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure in the power system, and the total amount of active power transmitted Including: determining the power system after each line fault according to the weight and electrical length of all transmission paths of the largest connected subnet after the failure of each line in the power system, and the total active power transmitted in the connected subnet The average transmission electrical distance. In this embodiment, when multiple connected subnets are generated after a fault, only the average transmission electrical distance of the largest connected subnet is evaluated, which is simple, convenient, and speeds up subsequent processing.

Corresponding to the power system vulnerability assessment method described in the above embodiment, FIG. 2 shows a schematic block diagram of a power system vulnerability assessment device provided by an embodiment of the present application. A plurality of units included in the power system vulnerability assessment device 200 of this embodiment are configured to perform multiple steps in the embodiment corresponding to FIG. 1, please refer to the related description in the embodiment corresponding to FIG. 1 and FIG. To repeat. The power system vulnerability assessment device 200 of this embodiment includes an average transmission electrical distance determination unit 201, a local voltage change determination unit 202, a local reactive power change determination unit 203, a reliability change determination unit 204, and a vulnerability determination unit 205 And the system weak link positioning unit 206. In this embodiment, the average transmission electrical distance determining unit 201 is configured to determine the power after the line fault according to the weights and electrical lengths of all transmission paths of the power system after each line fault in the power system, and the total amount of active power transmitted. The average transmission electrical distance of the system. The local voltage change determination unit 202 is configured to determine after each line failure according to the voltage of the target load node in the power system after each line failure and the voltage of the target load node before each line failure. The local voltage change amount of the power system, wherein the target load node is a load node whose voltage change amount after a line fault exceeds a preset voltage threshold. . The local reactive power change determining unit 203 is configured to be based on the reactive power output of the target generator node in the power system after each line fault and the reactive power output of the target generator node before each line fault, and The reactive power capacity of the target generator node determines a local reactive power change amount of the power system, wherein the target generator node is a power generator whose reactive power increase amount exceeds a preset multiple of its own reactive capacity after a line failure. Machine node. The reliability change determining unit 204 is configured to determine each of the load nodes according to the reliability indexes of all load nodes in the power system after each line fault and the reliability indexes of all load nodes before each fault. Reliability change of power system after line failure. The vulnerability determining unit 205 is configured to determine the each of the voltages based on the average transmission electrical distance, the local voltage variation, the local reactive power variation, and the reliability variation after each line fault. The vulnerability of a line. The system weak link positioning unit 206 is configured to locate the weak link of the power system according to the vulnerability of each line.

In one embodiment, the average transmission electrical distance determination unit 201, the local voltage change determination unit 202, the local reactive power change determination unit 203, the reliability change determination unit 204, the vulnerability determination unit 205, and the system weak link positioning unit 206. The corresponding average transmission electrical distance, local voltage change amount, local reactive power change amount, reliability change amount, comprehensive vulnerability and Weak links in the system are not described here.

The power system vulnerability assessment device in the embodiment of the present application solves the problem that the lack of vulnerability assessment in the related technology takes into consideration the electrical characteristics and the physical significance of the actual operation of the power system. From three aspects: branch roads, electrical paths, and power system parameter changes, The reliability evaluation of power system, the characteristics of components themselves, and the impact of components on system operation are used in the vulnerability assessment, not only considering the importance of branches and electrical paths in the topology connection relationship, but also considering the power The impact of system operation makes the results of line vulnerability assessment in the power system comprehensive and can reflect the real problems of the actual power system. At the same time, it analyzes the fragile lines of the power system and improves the reliability level, which can further guide the later upgrade of the power grid. , Applied to the grid planning and operation phase. Referring to FIG. 3, FIG. 3 is a schematic block diagram of another power system vulnerability assessment device according to another embodiment of the present application. The power system vulnerability assessment device 300 of this embodiment includes an average transmission electrical distance determination unit 301, a local voltage change determination unit 302, a local reactive power change determination unit 303, a reliability change determination unit 304, and a vulnerability determination unit 305. 2. The system weak link location unit 306 and the connected subnet determination unit 307.

In this embodiment, the average transmission electrical distance determination unit 301, the local voltage change determination unit 302, the local reactive power change determination unit 303, the reliability index determination unit 304, the vulnerability determination unit 305, and the system weak link positioning unit 306 are specific Please refer to FIG. 2 and the embodiment corresponding to FIG. 2, the average transmission electrical distance determination unit 201, the local voltage change determination unit 202, the local reactive power change determination unit 203, the reliability change determination unit 204, and the vulnerability determination unit 205 And related descriptions of the system weak link positioning unit 206, which are not repeated here.

In an embodiment, the power system vulnerability assessment device 300 further includes a connected subnet determination unit 307. The connected subnet determining unit 307 is configured to determine a largest connected subnet among the multiple connected subnets generated when the power system generates multiple connected subnets after the failure of each line. The average transmission electrical distance determination unit 301 is configured to determine each line according to the weights and electrical lengths of all transmission paths of the largest connected subnet after the failure of each line, and the total amount of active power transmitted. The average transmission electrical distance of the circuit system after a fault.

In an embodiment, the average transmission electrical distance determining unit is configured to be based on an expression

Determine the average transmission electrical distance D _l of the power system after a line l failure, where w _t represents the weight of line t in the power system after line l failure, len _t represents the electrical length of line t, and T (l) represents The set of all lines of the power system after line 1 failure, P _n represents the active power absorbed by node n after line 1 failure, and N refers to the set of all nodes of the power system.

In one embodiment, the local voltage change determination unit 302 is configured to be based on an expression

Determine the local voltage change amount V _l of the power system after the line 1 fault, where U _s and U _s0 represent the voltage of the target load node s after the line 1 fault and the voltage of the target load node s before the line 1 fault, S ( l) represents a set of target load nodes affected by a line 1 failure, wherein the target load node in the set of target load nodes has a voltage change amount after a line 1 failure exceeds a preset voltage threshold α ₁ .

In one embodiment, the local reactive power change determining unit is configured to be based on an expression

Determine the local reactive power change QQ _l of the power system after line 1 failure, where Q _g and Q _g0 represent the reactive power output of target generator node g after line 1 failure and the generator node before line 1 failure, respectively The reactive power output of g, Q _gmax represents the reactive power capacity of the generator node g, and G (l) represents the target generator node set affected by the fault of line l, wherein the generators in the target generator node set The increase of reactive power output of the node after the line 1 fault exceeds the preset reactive power α _{2 of the} generator node itself.

In an embodiment, the reliability change amount determining unit 304 is configured to be based on an expression

Determine the reliability change amount RR _l of the power system after line 1 failure, where R _n and R _n0 respectively represent the reliability index of load node n after line 1 failure and the reliability of load node n before line 1 failure Index, NL represents the set of all load nodes of the power system.

In one embodiment, the vulnerability determination unit 305 is configured to be based on an expression

Determine the vulnerability IV _{l of} line l, where rel (l) represents the reliability of line l,

Represents the average transmission electrical distance of the power system after a normalized line 1 failure,

Represents the local voltage change of the power system after a normalized line 1 failure,

Represents the local reactive power change of the power system after a normalized line 1 failure,

Represents the amount of change in the reliability of the power system after a normalized line 1 failure. Sorting the vulnerability according to the calculated vulnerability of each line can locate the weak links in the power system and guide the upgrading of the power system.

As can be seen from the above description, the embodiments of the present application solve the problem of lack of consideration of the electrical characteristics and the physical significance of the actual operation of the power system in the vulnerability assessment device in the related technology, and not only considers the importance of branches and electrical paths in the topology connection relationship. The impact of these electrical component failures on the operation of the power system is also considered, so that the results of the line vulnerability assessment in the power system are comprehensive and can reflect the real problems of the actual power system. At the same time, the vulnerable lines of the power system are analyzed to improve reliability. The performance level can further guide the later upgrading and transformation of the power grid, which is applied to the planning and operation phase of the power grid.

Referring to FIG. 4, FIG. 4 is a schematic block diagram of a power system vulnerability assessment terminal device according to an embodiment of the present application. As shown in FIG. 4, the power system vulnerability assessment terminal device 4 of this embodiment includes: a processor 40, a memory 41, and a computer program 42 stored in the memory 41 and executable on the processor 40, for example, Power system vulnerability assessment procedures. When the processor 40 executes the computer program 42, the power system vulnerability assessment method provided by any of the foregoing embodiments is implemented, such as steps 1010 to 1060 shown in FIG. 1. Alternatively, when the processor 40 executes the computer program 42, functions of multiple units in the foregoing device embodiment are implemented, for example, functions of units 301 to 307 shown in FIG. 3.

The computer program 42 may be divided into one or more modules / units, and the one or more modules / units are stored in the memory 41 and executed by the processor 40 to complete the present application. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program 42 in the power system vulnerability assessment terminal device 4. For example, the computer program 42 may be divided into an average transmission electrical distance determination unit, a local voltage change determination unit, a local reactive power change determination unit, a reliability index change determination unit, a vulnerability determination unit, and a connected subnet determination. The function of multiple units is as follows: Determine the power system after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure in the power system, and the total amount of active power transmitted. Determine the local voltage of the power system after each line failure according to the voltage of the target load node after each line failure and the voltage of the target load node before each line failure The amount of change, wherein the target load node is a load node whose voltage change amount after each line fault exceeds a preset voltage threshold; according to the reactive power output of the target generator node and Reactive power output of the target generator node before the line failure, and the target generator section Determine the local reactive power change of the power system after the failure of each line, wherein the target generator node increases the reactive power output after the line fault exceeds the reactive capacity of the generator node itself. Set multiple generator nodes; determine after each line failure according to the reliability indicators of all load nodes after each line failure and the reliability indicators of all load nodes before each line failure The amount of change in the reliability of the power system; determining the amount of each The vulnerability of each line; locate the weak link of the power system according to the vulnerability of each line.

In an embodiment, in a case where the power system generates multiple connected subnets after the failure of each line, determining the largest connected subnet among the multiple connected subnets generated; The weight and electrical length of all transmission paths of the power system after a line failure, and the total amount of active power transmitted, determining the average transmission electrical distance of the power system after each line failure includes: The weights and electrical lengths of all transmission paths of the largest connected subnet and the total amount of active power transmitted in the connected subnet are determined to determine the average transmission electrical distance of the power system after each line failure.

In one embodiment, according to the expression

Determine the average transmission electrical distance D _l of the power system after a line l failure, where w _t represents the weight of line t in the power system after line l failure, len _t represents the electrical length of line t, and T (l) represents The set of all lines of the power system after line 1 failure, Pn represents the active power absorbed by node n after line 1 failure, and N refers to the set of all nodes of the power system.

In one embodiment, according to the expression

Determine the local voltage change amount V1 of the power system after the line 1 failure, where U _s and U _s0 respectively represent the voltage of the target load node s after the line 1 failure and the voltage of the target load node s before the line 1 failure, S (l ) Represents a set of target load nodes affected by a line 1 failure, wherein the target load node in the set of target load nodes has a voltage change amount after a line 1 failure exceeds a preset voltage threshold α ₁

In one embodiment, according to the expression

Represents the amount of change in the reliability of the power system after a normalized line 1 failure

The power system vulnerability assessment terminal device 4 may be a computing device such as a desktop computer, a notebook, a palmtop computer, and a cloud server. The power system vulnerability assessment terminal device may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art can understand that FIG. 4 is only an example of the power system vulnerability assessment terminal device 4 and does not constitute a limitation on the power system vulnerability assessment terminal device 4. It may include more or fewer components than shown in the figure. Either certain components or different components are combined, for example, the power system vulnerability assessment terminal device may further include an input / output device, a network access device, a bus, and the like.

The so-called processor 40 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), Field-Programmable Gate Array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 41 may be an internal storage unit of the power system vulnerability assessment terminal device 4, such as a hard disk or a memory of the power system vulnerability assessment terminal device 4. The memory 41 may also be an external storage device of the power system vulnerability assessment terminal device 4, for example, a plug-in hard disk, a smart memory card (SMC) provided on the power system vulnerability assessment terminal device 4. ), Secure Digital (SD) cards, Flash Cards, etc. Further, the memory 41 may include both an internal storage unit of the power system vulnerability assessment terminal device 4 and an external storage device. The memory 41 is configured to store the computer program and other programs and data required by the power system vulnerability assessment terminal device. The memory 41 may also be configured to temporarily store data that has been output or is to be output.

For the convenience and brevity of the description, only the above-mentioned division of multiple functional units and modules is used as an example. In practical applications, the above functions may be allocated by different functional units and modules as needed, that is, the internal structure of the device. Divided into different functional units or modules to complete all or part of the functions described above. Multiple functional units and modules in the embodiment may be integrated into one processing unit, or multiple units may exist separately physically, or two or more units may be integrated into one unit. Implementation in the form of hardware can also be implemented in the form of software functional units. In addition, the names of the multiple functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the present application. For specific working processes of the units and modules in the foregoing system, reference may be made to corresponding processes in the foregoing method embodiments, and details are not described herein again.

In the above embodiments, the descriptions of the multiple embodiments have their respective focuses. For a part that is not detailed or recorded in an embodiment, reference may be made to related descriptions of other embodiments.

Those of ordinary skill in the art may realize that the units and algorithm steps of multiple examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

In the embodiments provided in this application, it should be understood that the disclosed apparatus / terminal device and method may be implemented in other ways. For example, the device / terminal device embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be another division manner, such as multiple units. Or components can be combined or integrated into another system. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, which may be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all units may be selected according to actual needs to achieve the objective of the solution of this embodiment.

In addition, multiple functional units in multiple embodiments of the present application may be integrated into one processing unit, or multiple units may exist separately physically, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional unit.

When the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, this application implements all or part of the processes in the method of the above embodiment, and can also be completed by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. The computer When the program is executed by a processor, the steps of any of the foregoing method embodiments can be implemented. The computer program includes computer program code, and the computer program code may be in a source code form, an object code form, an executable file, or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM) , Random Access Memory (Random Access Memory, RAM), electric carrier signals, telecommunication signals, and software distribution media.

Claims

A power system vulnerability assessment method includes:

Determining the average transmission electrical distance of the power system after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure in the power system, and the total amount of active power transmitted;

Determining the local voltage change amount of the power system after each line failure according to the voltage of the target load node after each line failure and the voltage of the target load node before each line failure, where The target load node is a load node whose voltage change after each line fault exceeds a preset voltage threshold;

Determining the target generator node based on the reactive power output of each line fault and the reactive power output of the target generator node before each line fault, and the target generator node's reactive power capacity The local reactive power change of the power system after each line failure, wherein the target generator node is a generator node whose increase in reactive power output after a line failure exceeds a preset multiple of the reactive capacity of the generator node;

Determining the reliability change amount of the power system after each line failure according to the reliability indicators of all load nodes after each line failure and the reliability indicators of all load nodes before each line failure ;

Determining the vulnerability of each line according to the average transmission electrical distance, the local voltage variation, the local reactive power variation, and the reliability variation after each line failure;

The weak link of the power system is located according to the vulnerability of each line.
The method according to claim 1, further comprising: in a case where the power system generates a plurality of connected subnets after the failure of each line, determining a largest connected subnet among the generated plurality of connected subnets;

The determining the average transmission electrical distance of the power system after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure in the power system and the total active power transmitted includes: The weights and electrical lengths of all transmission paths of the largest connected subnet after each line failure in the power system, and the total amount of active power transmitted in the largest connected subnet, determine what each The average transmission electrical distance of the power system is described.
The method according to claim 1, determining the power after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure in the power system, and the total amount of active power transmitted. The average transmission electrical distance of the system includes:

According to the expression
Determine the average transmission electrical distance D l of the power system after a line l failure, where w t represents the weight of line t in the power system after line l failure, len t represents the electrical length of line t, and T (l) represents The set of all lines of the power system after line 1 failure, P n represents the active power absorbed by node n after line 1 failure, and N refers to the set of all nodes of the power system.
The method according to claim 1, determining the power system after each line failure according to the voltage of the target load node after each line failure and the voltage of the target load node before each line failure The local voltage changes include:

According to the expression
Determine the local voltage change amount V l of the power system after the line 1 fault, where U s and U s0 represent the voltage of the target load node s after the line 1 fault and the voltage of the target load node s before the line 1 fault, S ( l) represents a set of target load nodes affected by a line 1 failure, wherein the target load node in the set of target load nodes has a voltage change amount after a line 1 failure exceeds a preset voltage threshold α 1 .
The method according to claim 1, according to the reactive power output of a target generator node after each line failure and the reactive power output of the target generator node before each line failure, and the target generator The reactive power capacity of the node, and determining the local reactive power change of the power system after each line fault includes:

According to the expression
Determine the local reactive power change QQ l of the power system after line 1 failure, where Q g and Q g0 represent the reactive power output of target generator node g after line 1 failure and the generator node before line 1 failure, respectively The reactive power output of g, Q gmax represents the reactive power capacity of the generator node g, and G (l) represents the target generator node set affected by the fault of line l, wherein the generators in the target generator node set The increase of reactive power output of the node after the line 1 fault exceeds the preset reactive power α 2 of the generator node itself.
The method according to claim 1, determining after each line failure according to the reliability indicators of all load nodes after each line failure and the reliability indicators of all load nodes before each line failure The reliability change of the power system includes:

According to the expression
Determine the change of the reliability index RR l of the power system after the line 1 fault, where R n and R n0 respectively represent the reliability index of the node n after the line 1 fault and the reliability index of the node n before the line 1 fault , NL represents the set of all load nodes of the power system.
The method according to claim 1, wherein the determining is based on the average transmission electrical distance, the local voltage variation, the local reactive power variation, and the reliability variation after each line fault. The vulnerability of each line includes:

According to the expression
Determine the vulnerability IV l of line l, where rel (l) represents the reliability of line l,
Represents the average transmission electrical distance of the power system after a normalized line 1 failure,
Represents the local voltage change of the power system after a normalized line 1 failure,
Represents the local reactive power change of the power system after a normalized line 1 failure,
Represents the amount of change in the reliability of the power system after a normalized line 1 failure.
A power system vulnerability assessment device includes:

The average transmission electrical distance determining unit is configured to determine the power after each line failure according to the weight and electrical length of all transmission paths of the power system after each line failure in the power system, and the total amount of active power transmitted. The average transmission electrical distance of the system;

The local voltage change determining unit is configured to determine the power system after each line failure according to the voltage of the target load node after each line failure and the voltage of the target load node before each line failure. A local voltage change amount, wherein the target load node is a load node whose voltage change amount after a line fault exceeds a preset voltage threshold;

The local reactive power change determining unit is configured to be based on the reactive power output of the target generator node after each line fault and the reactive power output of the target generator node before each line fault, and the target power generation. The reactive power capacity of the generator node determines the local reactive power change of the power system, wherein the target generator node is a generator node whose reactive power increase after a line failure exceeds a preset multiple of its reactive power capacity;

The reliability change determining unit is configured to determine after each line failure according to the reliability indicators of all load nodes after each line failure and the reliability indicators of all load nodes before each line failure. The amount of change in the reliability of the power system;

The vulnerability determining unit is configured to determine each of the lines according to the average transmission electrical distance, the local voltage change amount, the local reactive power change amount, and the reliability change amount after the failure of each line. The vulnerability of the line;

The system weak link positioning unit is configured to locate the weak link of the power system according to the vulnerability of each line.
A power system vulnerability assessment terminal device includes a memory, a processor, and a computer program stored in the memory and operable on the processor. The processor implements the computer program according to claim 1 when executing the computer program. The method according to any one of 7 to 7.
A computer-readable storage medium stores a computer program that, when executed by a processor, implements the method according to any one of claims 1 to 7.