Power system voltage stability evaluation and compensation method and system

Abstract

The invention relates to the technical field of power system optimization, in particular to a power system voltage stability evaluation and compensation method and system, and the method comprises the steps: quantifying a transient voltage disturbance index and a transient voltage peak index of each node, and obtaining a global transient voltage disturbance index and a global transient voltage peak index under each fault type; obtaining a global transient voltage disturbance index in each typical scene through the global transient voltage disturbance index; obtaining a global transient voltage peak index in each typical scene through the global transient voltage peak index; constructing a judgment decision matrix; analyzing the judgment decision matrix to obtain an overall stability index of the system; and a dynamic compensation strategy is formulated through the overall stability index of the system. According to the method, the accuracy of evaluating the overall stability index of the system is improved, and the stability of the system is improved through the overall stability index of the system.

Description

Technical Field

[0001] This invention relates to the field of power system optimization technology, and in particular to a method and system for assessing and compensating for voltage stability in power systems. Background Technology

[0002] With the increasing penetration of new energy sources such as wind power and photovoltaics in the power system, the randomness and volatility of their output have brought significant voltage stability problems to the power grid. Especially when a high proportion of new energy is integrated, new energy power plants are often located at the weak ends of the grid structure, and long-distance transmission easily leads to static and transient voltage instability. Existing voltage stability assessment methods (such as indices based on power balance, impedance, or sensitivity) mainly focus on static analysis, failing to adequately characterize the transient voltage recovery process after a fault, and lacking a systematic consideration of the impact of uncertainties in new energy sources. These methods are insufficient to meet the accuracy and real-time requirements of high-proportion new energy power grids for stability assessment. Therefore, there is an urgent need for a voltage stability index construction method that can effectively reflect the transient voltage characteristics of the system, take into account the uncertainty of photovoltaic output, and guide the configuration of dynamic reactive power compensation. Summary of the Invention

[0003] This invention provides a method and system for assessing and compensating voltage stability in power systems, which addresses the increasingly serious voltage stability problems in power grids and the shortcomings of related voltage stability assessment technologies as the penetration rate of new energy sources increases.

[0004] The objective of this invention can be achieved through the following technical solutions: The first aspect of this invention is to provide a method for assessing and compensating voltage stability in a power system, comprising: Based on the difference between the voltage of each node at each time point after the fault and the initial operating voltage, the transient voltage disturbance index of each node is obtained; based on the distribution of the transient voltage disturbance indices of all nodes, the global transient voltage disturbance index under each fault type is obtained; based on the voltage distribution of each node at all times after the fault, the transient voltage peak index of each node is obtained; based on the distribution of the transient voltage peak index of all nodes, the global transient voltage peak index under each fault type is obtained. Based on the global transient voltage disturbance index under each fault type, the global transient voltage disturbance index in each typical scenario is obtained; based on the global transient voltage peak index under each fault type, the global transient voltage peak index in each typical scenario is obtained; a judgment decision matrix is ​​constructed based on the global transient voltage disturbance index and the global transient voltage peak index in all typical scenarios; the comprehensive evaluation index of each typical scenario is determined through the analysis of the judgment decision matrix; the probability of occurrence of each typical scenario is obtained, and the overall system stability index is obtained based on the probability of occurrence of each typical scenario and the comprehensive evaluation index of each typical scenario. Dynamic compensation strategies are formulated based on the overall system stability index.

[0005] Furthermore, the step of obtaining the transient voltage disturbance index of each node based on the difference between the voltage of each node at each moment after the fault and the initial operating voltage includes:

[0006] In the formula, Indicates the first time after the fault The node at the th Voltage at a given moment Indicates the first The initial operating voltage of each node, Represents the absolute value symbol. Indicates the time when the fault is cleared. This indicates the cutoff time for calculating the transient voltage stability index. Represents the integral element with respect to the time variable. Indicates the fault type Next The transient voltage disturbance index of each node.

[0007] Furthermore, obtaining the global transient voltage disturbance index for each fault type based on the distribution of transient voltage disturbance indices across all nodes includes:

[0008] In the formula, Indicates the fault type Next The transient voltage disturbance index of each node; Represents the set of all nodes. Indicates the fault type The global transient voltage disturbance index under the given conditions. This indicates that the maximum value is taken from the transient voltage disturbance exponents of all nodes.

[0009] Further, based on the voltage distribution of each node at all times after the fault, the transient voltage peak index of each node is obtained; based on the distribution of the transient voltage peak indices of all nodes, the global transient voltage peak index under each fault type is obtained, including: The transient voltage peak exponent of each node is specifically expressed by the formula:

[0010] In the formula, Indicates the first time after the fault The node at the th Voltage at a given moment This represents the set of all times between the fault clearing time and the cutoff calculation time for the transient voltage stability index. Indicates the fault type Next The peak transient voltage exponent of each node; This represents all times corresponding to the fault clearing time and the cutoff calculation time of the transient voltage stability index. The maximum voltage of each node; The global transient voltage peak exponent for each fault type is specifically expressed by the following formula:

[0011] In the formula, Indicates the fault type Next The peak transient voltage exponent of each node; Represents the set of all nodes. Indicates the fault type The global transient voltage peak index under the condition, This indicates that the maximum value is taken from the peak transient voltage exponents of all nodes.

[0012] Further, the step of obtaining the global transient voltage disturbance index for each typical scenario based on the global transient voltage disturbance index under each fault type, and obtaining the global transient voltage peak index for each typical scenario based on the global transient voltage peak index under each fault type, includes: Identify all fault types in each typical scenario, and record the maximum value of the global transient voltage disturbance index under all fault types in each typical scenario as the global transient voltage disturbance index for each typical scenario; record the maximum value of the global transient voltage peak index under all fault types in each typical scenario as the global transient voltage peak index for each typical scenario. Each typical scenario contains several fault types.

[0013] Furthermore, a decision matrix is ​​constructed based on the global transient voltage disturbance index and the global transient voltage peak index in all typical scenarios; the comprehensive evaluation index for each typical scenario is determined through analysis of the decision matrix; the probability of occurrence of each typical scenario is obtained; and based on the probability of occurrence of each typical scenario and the comprehensive evaluation index of each typical scenario, the overall system stability index is obtained, including: The decision matrix is ​​specifically represented as follows:

[0014] In the formula, This represents the global transient voltage disturbance index in the first typical scenario. This represents the peak global transient voltage index in the first typical scenario. This represents the global transient voltage disturbance index in the second typical scenario. This represents the peak global transient voltage index in the second typical scenario. This represents the global transient voltage disturbance index in the third typical scenario. This represents the peak global transient voltage index in the third typical scenario; Represents the decision matrix; Based on the decision matrix, the comprehensive evaluation index for each typical scenario is obtained using the entropy weight TOPSIS method; Obtain the probability of occurrence for each typical scenario; the overall system stability index is specifically expressed by the formula:

[0015] In the formula, Indicates the first A comprehensive evaluation index for a typical scenario. Indicates the first The probability of a typical scenario occurring This indicates the number of all typical scenarios. This represents the overall stability index of the system.

[0016] Furthermore, the formulation of a dynamic compensation strategy based on the overall system stability index includes: When the overall system stability index When the system's overall stability index is high, STATCOM should be configured preferentially on nodes associated with high entropy weights; when the system's overall stability index is high... When the overall system stability index is high, SVC is used for economic compensation; when the overall system stability index is low... At that time, maintain the existing configuration; among which, Indicates the overall stability index of the system; in, This indicates a preset first threshold. This indicates a preset second threshold.

[0017] A second aspect of the present invention is to provide a power system voltage stability assessment and compensation system, comprising: Voltage index quantification module: used to obtain the transient voltage disturbance index of each node based on the difference between the voltage of each node at each moment after the fault and the initial operating voltage; to obtain the global transient voltage disturbance index under each fault type based on the distribution of the transient voltage disturbance indices of all nodes; to obtain the transient voltage peak index of each node based on the voltage distribution of each node at all moments after the fault; and to obtain the global transient voltage peak index under each fault type based on the distribution of the transient voltage peak index of all nodes. The overall system stability assessment module is used to obtain the global transient voltage disturbance index for each typical scenario based on the global transient voltage disturbance index under each fault type; to obtain the global transient voltage peak index for each typical scenario based on the global transient voltage peak index under each fault type; to construct a judgment decision matrix based on the global transient voltage disturbance index and the global transient voltage peak index for all typical scenarios; to determine the comprehensive evaluation index for each typical scenario through analysis of the judgment decision matrix; to obtain the probability of occurrence of each typical scenario; and to obtain the overall system stability index based on the probability of occurrence of each typical scenario and the comprehensive evaluation index for each typical scenario. Dynamic compensation module: Used to formulate dynamic compensation strategies based on the overall system stability index.

[0018] A third aspect of the present invention is to provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the power system voltage stability assessment and compensation method.

[0019] A fourth aspect of the present invention is to provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the power system voltage stability assessment and compensation method.

[0020] Compared with the prior art, the beneficial effects of this invention are: obtaining the transient voltage disturbance index of each node based on the difference between the voltage of each node at each moment after a fault and the initial operating voltage; obtaining the global transient voltage disturbance index for each fault type based on the distribution of the transient voltage disturbance indices of all nodes; obtaining the transient voltage peak index of each node based on the voltage distribution of each node at all moments after a fault; obtaining the global transient voltage peak index for each fault type based on the distribution of the transient voltage peak indices of all nodes; improving the accuracy of voltage stability index assessment; and obtaining the global transient voltage disturbance index for each typical scenario based on the global transient voltage disturbance index for each fault type. Based on the global transient voltage peak index under each fault type, the global transient voltage peak index in each typical scenario is obtained, improving the accuracy of voltage stability index analysis in typical scenarios. A judgment decision matrix is ​​constructed based on the global transient voltage disturbance index and the global transient voltage peak index in all typical scenarios. The comprehensive evaluation index of each typical scenario is determined through the analysis of the judgment decision matrix. The probability of occurrence of each typical scenario is obtained, and the overall system stability index is obtained based on the probability of occurrence of each typical scenario and the comprehensive evaluation index of each typical scenario. Dynamic compensation strategies are formulated through the overall system stability index, improving the accuracy of the overall system stability index assessment and enhancing the system stability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This invention provides a flowchart illustrating the steps of a power system voltage stability assessment and compensation method. Figure 2 This invention provides a schematic diagram of the module flow of a power system voltage stability assessment and compensation system. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] To address the problems existing in the background technology, a method and system for voltage stability assessment and compensation in power systems have been developed, which has significant practical implications.

[0026] like Figure 1 As shown, the first aspect of the present invention is to provide a method for assessing and compensating voltage stability in a power system, comprising the following steps: Step S001: Quantify the transient voltage disturbance index and transient voltage peak index of each node, and use them to obtain the global transient voltage disturbance index and global transient voltage peak index under each fault type.

[0027] It should be noted that, in order to accurately quantify the transient voltage behavior characteristics of high-proportion renewable energy power systems under fault disturbances, traditional voltage stability indicators are mostly based on steady-state or static assumptions, which cannot effectively capture the dynamic recovery process and overvoltage risk of the system after fault clearance. By introducing these transient indicators, we can objectively reflect the weak links and risk distribution of different nodes in the system during the transient process from two dimensions: the severity of voltage deviation and the height of voltage peak. This provides a quantifiable data foundation for subsequent multi-scenario comprehensive evaluation and precise reactive power compensation, thereby enhancing the perception and control capabilities of system transient stability.

[0028] Specifically, the fault type is input, and the transient voltage disturbance index of each node is obtained based on the difference between the voltage of each node at each time point after the fault and the initial operating voltage. The transient voltage disturbance index of each node is specifically expressed by the formula (continuity):

[0029] In the formula, Indicates the first time after the fault The node at the th Voltage at a given moment Indicates the first The initial operating voltage of each node, Represents the absolute value symbol. Indicates the time when the fault is cleared. This indicates the cutoff time for calculating the transient voltage stability index. Represents the integral element with respect to the time variable. Indicates the fault type Next The transient voltage disturbance index of each node.

[0030] To facilitate programming calculations, it is discretized; the transient voltage disturbance exponent of each node is specifically expressed by the formula (continuity):

[0031] In the formula, Indicates the first time after the fault The node at the th Voltage at a given moment Indicates the first The initial operating voltage of each node, Represents the absolute value symbol. This indicates the step size of the time-domain simulation (i.e., the time interval between two adjacent simulation data points). This indicates the number of data points between the fault clearing time and the cutoff calculation time for the transient voltage stability index. Indicates the fault type Next The transient voltage disturbance index of each node.

[0032] in, This represents the difference between the voltage of each node at each moment after a fault and the initial operating voltage. The larger the difference, the greater the voltage disturbance; conversely, the smaller the difference, the smaller the voltage disturbance. This indicates the relative change of voltage variation after a fault relative to the initial operating voltage, and represents the relative rate of change of the voltage variation.

[0033] Based on the distribution of transient voltage disturbance indices across all nodes, the global transient voltage disturbance index for each fault type is obtained; the global transient voltage disturbance index is specifically expressed by the formula:

[0034] In the formula, Indicates the fault type Next The transient voltage disturbance index of each node; Represents the set of all nodes. Indicates the fault type The global transient voltage disturbance index under the given conditions. This indicates that the maximum value is taken from the transient voltage disturbance exponents of all nodes.

[0035] Based on the voltage distribution of each node at all times after the fault, the transient voltage peak index of each node is obtained; the specific formula for the transient voltage peak index of each node is as follows:

[0036] In the formula, Indicates the first time after the fault The node at the th Voltage at a given moment This represents the set of all times between the fault clearing time and the cutoff calculation time for the transient voltage stability index. Indicates the fault type Next The peak transient voltage exponent of each node; This represents all times corresponding to the fault clearing time and the cutoff calculation time of the transient voltage stability index. The maximum voltage of each node.

[0037] Based on the distribution of transient voltage peak indices across all nodes, the global transient voltage peak index for each fault type is obtained; the global transient voltage peak index is specifically expressed by the formula:

[0038] In the formula, Indicates the fault type Next The peak transient voltage exponent of each node; Represents the set of all nodes. Indicates the fault type The global transient voltage peak index under the condition, This indicates that the maximum value is taken from the peak transient voltage exponents of all nodes.

[0039] Thus, the global transient voltage disturbance index and the global transient voltage peak index for each fault type are obtained using the above method.

[0040] Step S002: Obtain the global transient voltage disturbance index for each typical scenario through the global transient voltage disturbance index; obtain the global transient voltage peak index for each typical scenario through the global transient voltage peak index; construct a judgment decision matrix in this way; obtain the overall system stability index through the judgment decision matrix analysis.

[0041] It should be noted that, in order to address the challenges posed by the uncertainty of photovoltaic output in high-proportion renewable energy power systems to transient voltage stability assessment, traditional single-scenario assessments cannot reflect the true operational risks of the system. Therefore, based on probability theory, it is necessary to divide the randomness of photovoltaic output into several representative typical scenarios (such as high, medium, and low output), and calculate the global transient voltage stability index defined in Stage 1 for each scenario. and By using the entropy-weighted TOPSIS method to comprehensively evaluate and weight and fuse these multi-scenario indicators, a comprehensive index SI that can measure the stability level of the system under different operating conditions is obtained. This approach ensures that the evaluation results are no longer dependent on a specific operating point, but rather cover all possible situations that may occur in photovoltaic systems, thus providing a more reliable and realistic theoretical basis for subsequent stability decisions and reactive power compensation configuration.

[0042] Specifically, based on scenario probability theory, the uncertainty of photovoltaic output is divided into several typical scenarios; all fault types in each typical scenario are identified; the maximum value of the global transient voltage disturbance index under all fault types in each typical scenario is denoted as the global transient voltage disturbance index for each typical scenario; the maximum value of the global transient voltage peak index under all fault types in each typical scenario is denoted as the global transient voltage peak index for each typical scenario. It should be noted that each typical scenario contains several fault types.

[0043] A decision matrix is ​​constructed based on the global transient voltage disturbance index and the global transient voltage peak index in all typical scenarios. This embodiment selects three typical scenarios for illustration, but no specific limitations are imposed; implementers can determine the appropriate scenarios based on specific circumstances. The decision matrix is ​​specifically represented as follows:

[0044] In the formula, This represents the global transient voltage disturbance index in the first typical scenario. This represents the peak global transient voltage index in the first typical scenario. This represents the global transient voltage disturbance index in the second typical scenario. This represents the peak global transient voltage index in the second typical scenario. This represents the global transient voltage disturbance index in the third typical scenario. This represents the peak global transient voltage index in the third typical scenario; This represents the decision matrix.

[0045] Based on the decision matrix, the comprehensive evaluation index of each typical scenario is obtained through the entropy weight TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method; among which, the entropy weight TOPSIS method is a well-known technique and will not be described in detail here.

[0046] Obtain the probability of each typical scenario occurring; where the sum of the probabilities of all typical scenarios occurring must be 1.

[0047] The overall system stability index is obtained based on the probability of occurrence of each typical scenario and the comprehensive evaluation index of each typical scenario; the overall system stability index is specifically expressed by the formula:

[0048] In the formula, Indicates the first A comprehensive evaluation index for a typical scenario. Indicates the first The probability of a typical scenario occurring This indicates the number of all typical scenarios. This represents the overall stability index of the system.

[0049] The probability of each typical scenario occurring is used as the weight of the comprehensive evaluation index for the typical scenario to adjust the comprehensive evaluation index.

[0050] Thus, the overall system stability index is obtained through the above method.

[0051] Step S003: Formulate a dynamic compensation strategy based on the overall system stability index.

[0052] It should be noted that the System Stability Index (SI) calculated in the aforementioned assessment is transformed into a specific and executable reactive power compensation configuration scheme to achieve precise improvement and economic optimization of system transient voltage stability. This is necessary because simple assessment and diagnosis cannot directly guarantee grid safety; effective control actions must be taken based on the assessment conclusions. By setting SI thresholds (α, β), the system's stability state can be classified (critical, warning, safe), and the most suitable compensation device can be automatically matched accordingly (such as the fast-response STATCOM (Static Synchronous Compensator) to handle critical situations, and the more economical SVC (Static Var Compensator) to handle warning states). This ensures that the system does not experience voltage instability while avoiding over-investment, achieving a balance between safety and economy. This stage represents the ultimate value of the entire method, completing the closed loop from "problem analysis" to "problem solving."

[0053] Specifically, candidate buses are dynamically compensated based on the index SI to maintain system stability; the specific dynamic compensation is as follows: When the overall system stability index When the system's overall stability index is high, STATCOM should be configured preferentially on nodes associated with high entropy weights; when the system's overall stability index is high... When the overall system stability index is high, SVC is used for economic compensation; when the overall system stability index is low... At that time, maintain the existing configuration.

[0054] in, This indicates a preset first threshold. This indicates a preset second threshold; wherein in this embodiment, a preset first threshold is used. Preset second threshold In this embodiment, a preset first threshold is used. and preset second threshold No specific limitations are set; implementers can determine the implementation based on specific circumstances. and The weights of the indicators determined by the entropy weight method are dynamically adjusted.

[0055] This completes the dynamic compensation for system stability.

[0056] The experimental data based on the above dynamic compensation example are as follows: Taking the improved IEEE 39-node system as an example, the specific implementation of the present invention is illustrated as follows: In the MATLAB environment, the improved IEEE 39-node system was modeled using the PSAT toolkit. The photovoltaic power station was connected to the grid through nodes 30 and 38, and the photovoltaic penetration rate reached 20.3%, which meets the high penetration rate requirement.

[0057] Based on the scenario probability theory, typical photovoltaic output scenarios PV.1, PV.2 and PV.3 are constructed. The probabilities of occurrence of scenarios PV.1-PV.3 are 0.0616, 0.8115 and 0.1269, respectively. The operating probability and output power of photovoltaic units under each typical scenario are calculated. Under typical severe fault conditions, the transient voltage disturbance index and transient voltage peak index of each node are calculated, and then the global transient voltage disturbance index and global transient voltage peak index are obtained. For typical photovoltaic scenarios PV.1-PV.3, the global transient voltage disturbance index and the global transient voltage peak index are selected as the corresponding indicators. The indicator values ​​of PV.1-PV.3 scenarios are collected to construct a judgment decision matrix. Among them, the decision matrix is ​​used for judgment.

[0058] Calculated based on the entropy weight TOPSIS method and The weights are 0.96 and 0.04 respectively; the comprehensive evaluation indices for PV.1-PV.3 scenarios are 0, 0.66 and 1 respectively; by weighting the comprehensive evaluation index of each typical scenario with the probability of scenario occurrence, the overall system stability index SI is obtained as 0.66.

[0059] Set threshold parameters , ,because By configuring SVCs on the associated photovoltaic nodes 30 and 38, the overall system stability index SI was increased to 0.82, which improved the transient voltage stability of the system.

[0060] This concludes the embodiment.

[0061] like Figure 2 As shown, a second aspect of the present invention is to provide a power system voltage stability assessment and compensation system, comprising: Voltage index quantification module 101: used to obtain the transient voltage disturbance index of each node based on the difference between the voltage of each node at each time after the fault and the initial operating voltage; to obtain the global transient voltage disturbance index under each fault type based on the distribution of the transient voltage disturbance indices of all nodes; to obtain the transient voltage peak index of each node based on the voltage distribution of each node at all times after the fault; and to obtain the global transient voltage peak index under each fault type based on the distribution of the transient voltage peak index of all nodes. System overall stability assessment module 102: This module is used to obtain the global transient voltage disturbance index for each typical scenario based on the global transient voltage disturbance index under each fault type; to obtain the global transient voltage peak index for each typical scenario based on the global transient voltage peak index under each fault type; to construct a judgment decision matrix based on the global transient voltage disturbance index and the global transient voltage peak index for all typical scenarios; to determine the comprehensive evaluation index for each typical scenario through analysis of the judgment decision matrix; to obtain the probability of occurrence of each typical scenario; and to obtain the overall system stability index based on the probability of occurrence of each typical scenario and the comprehensive evaluation index for each typical scenario. Dynamic compensation module 103: Used to formulate dynamic compensation strategies based on the overall system stability index.

[0062] A third aspect of the present invention is to provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a method for assessing and compensating voltage stability in a power system.

[0063] A fourth aspect of the present invention is to provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements a method for assessing and compensating voltage stability in a power system.

[0064] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, etc.) containing computer-usable program code.

[0065] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, systems, and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0066] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0067] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for assessing and compensating voltage stability in a power system, characterized in that, include: The transient voltage disturbance index of each node is obtained based on the difference between the voltage of each node at each time point after the fault and the initial operating voltage. Based on the distribution of transient voltage disturbance indices of all nodes, the global transient voltage disturbance index for each fault type is obtained; based on the voltage distribution of each node at all times after the fault, the transient voltage peak index of each node is obtained; based on the distribution of transient voltage peak indices of all nodes, the global transient voltage peak index for each fault type is obtained. Based on the global transient voltage disturbance index under each fault type, the global transient voltage disturbance index in each typical scenario is obtained. Based on the global transient voltage peak index under each fault type, the global transient voltage peak index in each typical scenario is obtained; a judgment decision matrix is ​​constructed based on the global transient voltage disturbance index and the global transient voltage peak index in all typical scenarios. The comprehensive evaluation index of each typical scenario is determined by the judgment decision matrix analysis; the probability of occurrence of each typical scenario is obtained, and the overall stability index of the system is obtained based on the probability of occurrence of each typical scenario and the comprehensive evaluation index of each typical scenario. Dynamic compensation strategies are formulated based on the overall system stability index.

2. The power system voltage stability assessment and compensation method according to claim 1, characterized in that, The method of obtaining the transient voltage disturbance index of each node based on the difference between the voltage of each node at each moment after the fault and the initial operating voltage includes: In the formula, Indicates the first time after the fault The node at the th Voltage at a given moment Indicates the first The initial operating voltage of each node, Represents the absolute value symbol. Indicates the time when the fault is cleared. This indicates the cutoff time for calculating the transient voltage stability index. Represents the integral element with respect to the time variable. Indicates the fault type Next The transient voltage disturbance index of each node.

3. The power system voltage stability assessment and compensation method according to claim 1, characterized in that, The process of obtaining the global transient voltage disturbance index for each fault type based on the distribution of transient voltage disturbance indices across all nodes includes: In the formula, Indicates the fault type Next The transient voltage disturbance index of each node; Represents the set of all nodes. Indicates the fault type The global transient voltage disturbance index under the given conditions. This indicates that the maximum value is taken from the transient voltage disturbance exponents of all nodes.

4. The power system voltage stability assessment and compensation method according to claim 1, characterized in that, The transient voltage peak index of each node is obtained based on the voltage distribution of each node at all times after the fault. Based on the distribution of transient voltage peak exponents across all nodes, the global transient voltage peak exponent for each fault type is obtained, including: The transient voltage peak exponent of each node is specifically expressed by the formula: In the formula, Indicates the first time after the fault The node at the th Voltage at a given moment This represents the set of all times between the fault clearing time and the cutoff calculation time for the transient voltage stability index. Indicates the fault type Next The peak transient voltage exponent of each node; This represents all times corresponding to the fault clearing time and the cutoff calculation time of the transient voltage stability index. The maximum voltage of each node; The global transient voltage peak exponent for each fault type is specifically expressed by the following formula: In the formula, Indicates the fault type Next The peak transient voltage exponent of each node; Represents the set of all nodes. Indicates the fault type The global transient voltage peak index under the condition, This indicates that the maximum value is taken from the peak transient voltage exponents of all nodes.

5. The power system voltage stability assessment and compensation method according to claim 1, characterized in that, The global transient voltage disturbance index for each typical scenario is obtained based on the global transient voltage disturbance index under each fault type. Based on the global transient voltage peak index under each fault type, the global transient voltage peak index for each typical scenario is obtained, including: Identify all fault types in each typical scenario, and record the maximum value of the global transient voltage disturbance index under all fault types in each typical scenario as the global transient voltage disturbance index for each typical scenario; record the maximum value of the global transient voltage peak index under all fault types in each typical scenario as the global transient voltage peak index for each typical scenario. Each typical scenario contains several fault types.

6. The power system voltage stability assessment and compensation method according to claim 1, characterized in that, The decision matrix is ​​constructed based on the global transient voltage disturbance index and the global transient voltage peak index in all typical scenarios. The comprehensive evaluation index for each typical scenario is determined by analyzing the decision matrix. Obtain the probability of occurrence for each typical scenario. Based on the probability of occurrence of each typical scenario and the comprehensive evaluation index of each typical scenario, obtain the overall system stability index, including: The decision matrix is ​​specifically represented as follows: In the formula, This represents the global transient voltage disturbance index in the first typical scenario. This represents the peak global transient voltage index in the first typical scenario. This represents the global transient voltage disturbance index in the second typical scenario. This represents the peak global transient voltage index in the second typical scenario. This represents the global transient voltage disturbance index in the third typical scenario. This represents the peak global transient voltage index in the third typical scenario; Represents the decision matrix; Based on the decision matrix, the comprehensive evaluation index for each typical scenario is obtained using the entropy weight TOPSIS method; Obtain the probability of occurrence for each typical scenario; The overall system stability index is specifically expressed by the formula: In the formula, Indicates the first A comprehensive evaluation index for a typical scenario. Indicates the first The probability of a typical scenario occurring This indicates the number of all typical scenarios. This represents the overall stability index of the system.

7. The power system voltage stability assessment and compensation method according to claim 1, characterized in that, The method of formulating a dynamic compensation strategy based on the overall system stability index includes: When the overall system stability index When the system's overall stability index is high, STATCOM should be configured preferentially on nodes associated with high entropy weights; when the system's overall stability index is high... When the overall system stability index is high, SVC is used for economic compensation; when the overall system stability index is low... At that time, maintain the existing configuration; among which, Indicates the overall stability index of the system; in, This indicates a preset first threshold. This indicates a preset second threshold.

8. A power system voltage stability assessment and compensation system, characterized in that, include: Voltage index quantification module: used to obtain the transient voltage disturbance index of each node based on the difference between the voltage of each node at each moment after the fault and the initial operating voltage; to obtain the global transient voltage disturbance index under each fault type based on the distribution of the transient voltage disturbance indices of all nodes; to obtain the transient voltage peak index of each node based on the voltage distribution of each node at all moments after the fault; and to obtain the global transient voltage peak index under each fault type based on the distribution of the transient voltage peak index of all nodes. The overall system stability assessment module is used to obtain the global transient voltage disturbance index for each typical scenario based on the global transient voltage disturbance index under each fault type; to obtain the global transient voltage peak index for each typical scenario based on the global transient voltage peak index under each fault type; and to construct a judgment decision matrix based on the global transient voltage disturbance index and the global transient voltage peak index for all typical scenarios. The comprehensive evaluation index for each typical scenario is determined by analyzing the decision matrix. Obtain the probability of occurrence of each typical scenario, and based on the probability of occurrence of each typical scenario and the comprehensive evaluation index of each typical scenario, obtain the overall stability index of the system. Dynamic compensation module: Used to formulate dynamic compensation strategies based on the overall system stability index.

9. An electronic device, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the power system voltage stability assessment and compensation method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the power system voltage stability assessment and compensation method according to any one of claims 1-7.

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