An electromagnetic hybrid distribution network flexible interconnection device state evaluation method

Abstract

The present application relates to a kind of electromagnetic hybrid type distribution network flexible interconnection device state evaluation method, comprising the following steps: constructing the comprehensive evaluation index system of electromagnetic hybrid type distribution network flexible interconnection device, it contains multiple first-level indicators, each first-level indicator further contains multiple second-level indicators;By analytic hierarchy process, establish hierarchical structure model, construct judgment matrix, and then determine the subjective weight of first-level indicator and second-level indicator;Using entropy weight method, establish index data standardization matrix, determine the objective weight of first-level indicator and second-level indicator by calculating entropy and difference coefficient;Determine the comprehensive weight by the subjective weight and objective weight of first-level indicator and second-level indicator;Determine the evaluation factor set and comment set of the object to be evaluated, and construct membership matrix;Combined with comprehensive weight and membership matrix, based on binary semantics, determine evaluation grade.The method can efficiently, accurately and comprehensively evaluate the running state of electromagnetic hybrid type distribution network flexible interconnection device.

Description

Technical Field

[0001] This invention belongs to the field of flexible interconnection technology of distribution networks, and specifically relates to a condition evaluation method for electromagnetic hybrid flexible interconnection devices in distribution networks. Background Technology

[0002] As the main battleground for the construction of the energy internet, the development of distribution networks is characterized by AC / DC interconnection, a high proportion of distributed renewable energy, and large-scale access of power electronic equipment, facing the dual challenges of ensuring continuous and stable supply and accelerating the clean and low-carbon transformation. Flexible interconnection technology for distribution networks combines flexible power electronic control technology with optimized distribution network design. It can provide fast and accurate active and reactive power control, power outage support, and power quality management functions between distribution network lines and substations. This provides an effective technical means to tap the power supply potential of distribution networks and improve power supply reliability, and is an important technical route to solve the problem of high-proportion distributed power generation in distribution networks. At the same time, through flexible DC interconnection, low-voltage distribution substations can achieve dynamic capacity expansion and rapid fault transfer in the near term, improving power supply reliability and the capacity to accommodate distributed power sources. In the long term, through flexible low-voltage AC / DC networking, it can adapt to large-scale multi-mode source and load access, achieving the goal of flexible and efficient interaction between source, grid, load, and storage.

[0003] Power electronic devices, represented by flexible multi-state switches, are currently the main form of flexible interconnection devices in distribution networks. However, the extensive use of power electronic components has also led to their common drawbacks: huge initial investment and cumbersome subsequent maintenance, which limits their application in distribution networks. Electromagnetic flexible interconnection devices for distribution networks, utilizing novel phase-shifting transformer topologies and combined with new electronic switches and control strategies, can rapidly adjust the power flow distribution of the distribution network to meet system requirements.

[0004] Currently, research on electromagnetic hybrid flexible interconnection technology for medium and low voltage distribution networks mainly focuses on grid structure and topology, key equipment, and operation control. Effective research on the operation and maintenance mechanisms and strategies for electromagnetic hybrid flexible interconnection devices is still lacking. Therefore, it is necessary to conduct research on the condition assessment of electromagnetic hybrid flexible interconnection devices in distribution networks. Summary of the Invention

[0005] The purpose of this invention is to provide a method for evaluating the status of electromagnetic hybrid distribution network flexible interconnection devices. This method can efficiently, accurately, and comprehensively evaluate the operating status of electromagnetic hybrid distribution network flexible interconnection devices.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: 1. A method for evaluating the condition of an electromagnetic hybrid type flexible interconnection device for power distribution networks, characterized by comprising the following steps:

[0007] Step S1: Construct a comprehensive evaluation index system for electromagnetic hybrid distribution network flexible interconnection devices. The comprehensive evaluation index system includes multiple primary indicators, and each primary indicator further includes multiple secondary indicators.

[0008] Step S2: Establish a hierarchical structure model using the analytic hierarchy process (AHP), construct a judgment matrix using the established hierarchical structure model, and then determine the subjective weights of the primary and secondary indicators.

[0009] Step S3: Establish a standardized matrix of indicator data using the entropy weight method, and determine the objective weights of primary and secondary indicators by calculating the entropy value and the difference coefficient;

[0010] Step S4: Determine the comprehensive weight by combining the subjective and objective weights of the primary and secondary indicators;

[0011] Step S5: Determine the set of evaluation factors and comments for the object to be evaluated, and construct the membership matrix of the primary and secondary indicators;

[0012] Step S6: Combine the comprehensive weight with the membership matrix of the primary and secondary indicators to determine the evaluation level based on binary semantics.

[0013] Furthermore, in step S1, based on the multi-dimensional test results of the relevant components / capabilities of the electromagnetic hybrid distribution network flexible interconnection device, a secondary evaluation index system containing 30 secondary indicators is established. The secondary evaluation index system containing 30 secondary indicators further constitutes a primary evaluation index system containing 6 primary indicators, thereby obtaining a comprehensive evaluation index system for the electromagnetic hybrid distribution network flexible interconnection device.

[0014] Furthermore, the six primary indicators are: insulation performance, short-circuit withstand performance, load performance, energy efficiency performance, self-protection performance, and voltage regulation performance.

[0015] Furthermore, the insulation performance includes the following secondary indicators: equipment operating years, insulation within 2km of the surrounding area, body oil chromatography, bushing main insulation capacitance, body oil dielectric loss, body oil withstand voltage, body oil micro-water content, on-load tap changer oil withstand voltage, winding insulation resistance, winding and bushing dielectric loss and bushing main insulation resistance.

[0016] The short-circuit withstand performance includes the following secondary indicators: equipment service life, number of short-circuit impacts, winding frequency response, and low-voltage short-circuit impedance.

[0017] The load performance includes the following secondary indicators: annual heavy overload duration, real-time oil temperature of the main transformer, offline body oil chromatography, online body oil chromatography, offline core grounding current, online core grounding current, and bushing oil chromatography.

[0018] The energy efficiency performance includes the following secondary indicators: annual heavy overload duration, equipment operating years, no-load current and no-load loss, and no-load loss and energy efficiency.

[0019] The self-protection performance includes the following secondary indicators: main body light gas and cooler failure and complete shutdown signal;

[0020] The voltage regulation performance includes the following secondary indicators: the risk of on-load tap changer over-cycle and the number of on-load tap changer operations.

[0021] Furthermore, in step S2, for the electromagnetic hybrid distribution network flexible interconnection device, based on the established comprehensive evaluation index system, the relationship between the evaluation objectives, evaluation criteria and evaluation indicators is analyzed by the analytic hierarchy process, and then a hierarchical structure model is established. The importance of the evaluation criteria layer and the evaluation indicator layer belonging to the same evaluation criteria layer is compared pairwise, and a judgment matrix is ​​constructed to solve for the weights, thereby determining the subjective weights of the first-level indicators and the second-level indicators.

[0022] Furthermore, in step S3, for electromagnetic hybrid distribution network flexible interconnection devices, based on the established comprehensive evaluation index system, an index data standardization matrix is ​​established using the entropy weight method. The greater the difference between the indicators, the more information they can feedback, and the smaller the entropy value, thereby determining the objective weights of the primary and secondary indicators.

[0023] Furthermore, in step S4, based on the subjective weights of the primary and secondary indicators obtained using the analytic hierarchy process and the objective weights of the primary and secondary indicators obtained using the entropy weight method, the comprehensive weights of the primary and secondary indicators are calculated using the combined weighting method.

[0024] Furthermore, in step S5, the electromagnetic hybrid distribution network flexible interconnection device is taken as the object to be evaluated. As the set of factors affecting the object to be evaluated, the set of evaluation factors is the established comprehensive evaluation index system, and the set of comments is the set of possible evaluation levels. The evaluation levels are divided into four levels: "poor", "average", "medium" and "good". Then the set of comments W = {W1, W2, W3, W4} = {poor, average, medium, good}.

[0025] Calculate the attribution level W for each secondary indicator. d The degree of hierarchical affiliation, and the level W to which each primary indicator belongs. d The membership degrees of the first-level and second-level indicators are obtained by finding the membership degree matrix of the first-level and second-level indicators, where d = 1, 2, 3, 4.

[0026] Furthermore, in step S6, since different indicators contribute differently to the grade evaluation, the comprehensive weights of all first-level and second-level indicators are represented in vector form. The weight vectors are combined with the membership matrix using a weighted average composite operator to obtain the comprehensive membership.

[0027] When the gaps between the evaluation index data corresponding to different evaluation levels are not equal, the evaluation results based on the principle of maximum membership may differ significantly from the actual situation. Therefore, level feature values ​​are introduced and combined with binary semantics to achieve level determination. According to the judgment method of binary semantics, the level feature values ​​are first determined, and then the level feature values ​​are further represented in matrix form. Finally, the evaluation level is determined based on the relevant meaning of binary semantics.

[0028] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a status evaluation method for electromagnetic hybrid distribution network flexible interconnection devices. This method can efficiently, accurately and comprehensively evaluate the operating status of electromagnetic hybrid distribution network flexible interconnection devices, making the determination of the operating status of electromagnetic hybrid distribution network flexible interconnection devices more objective and reasonable. This is conducive to on-site operation and maintenance personnel to formulate maintenance plans based on the status evaluation of distribution network flexible interconnection devices, and better support equipment management business. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating the method implementation of an embodiment of the present invention;

[0030] Figure 2 This is a diagram of the comprehensive evaluation index system established in the embodiments of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] like Figure 1As shown, this embodiment provides a condition evaluation method for a flexible interconnection device in an electromagnetic hybrid distribution network, including the following steps:

[0035] Step S1: Construct a comprehensive evaluation index system for electromagnetic hybrid distribution network flexible interconnection devices. The comprehensive evaluation index system includes multiple primary indicators, and each primary indicator further includes multiple secondary indicators.

[0036] In this embodiment, based on the multi-dimensional test results of the relevant components / capabilities of the electromagnetic hybrid distribution network flexible interconnection device, a secondary evaluation index system containing 30 secondary indicators is established. The secondary evaluation index system containing 30 secondary indicators further constitutes a primary evaluation index system containing 6 primary indicators, thereby obtaining a comprehensive evaluation index system for the electromagnetic hybrid distribution network flexible interconnection device.

[0037] like Figure 2 As shown, the six primary indicators are: insulation performance, short-circuit withstand performance, load performance, energy efficiency performance, self-protection performance, and voltage regulation performance.

[0038] The insulation performance includes the following secondary indicators: equipment operating years, insulation within 2km of the surrounding area, body oil chromatography, bushing main insulation capacitance, body oil dielectric loss, body oil withstand voltage, body oil moisture content, on-load tap changer oil withstand voltage, winding insulation resistance, winding and bushing dielectric loss, and bushing main insulation resistance.

[0039] The secondary indicators of the short-circuit withstand performance include: equipment operating years, number of short-circuit impacts, winding frequency response, and low-voltage short-circuit impedance.

[0040] The load performance includes the following secondary indicators: annual heavy overload duration, real-time oil temperature of the main transformer, offline body oil chromatography, online body oil chromatography, offline core grounding current, online core grounding current, and bushing oil chromatography.

[0041] The energy efficiency performance includes the following secondary indicators: annual heavy overload duration, equipment operating years, no-load current and no-load loss, and no-load loss and energy efficiency.

[0042] The self-protection performance includes the following secondary indicators: main body light gas and cooler failure and complete shutdown signal.

[0043] The voltage regulation performance includes the following secondary indicators: the risk of on-load tap changer over-cycle and the number of on-load tap changer operations.

[0044] Step S2: Establish a hierarchical structure model using the analytic hierarchy process (AHP), construct a judgment matrix using the established hierarchical structure model, and then determine the subjective weights of the primary and secondary indicators.

[0045] The Analytic Hierarchy Process (AHP) refers to a hierarchical model established for complex and fuzzy systems by clarifying the relationships between objectives, criteria, and indicators. It compares the importance of each criterion layer and each indicator layer belonging to the same criterion layer pairwise, constructing a judgment matrix to solve for the weights. In this embodiment, for a flexible interconnection device in an electromagnetic hybrid distribution network, based on the established comprehensive evaluation index system, the AHP is used to analyze the relationships between evaluation objectives, evaluation criteria, and evaluation indicators, thereby establishing a hierarchical model. The importance of each evaluation criterion layer and each evaluation indicator layer belonging to the same evaluation criterion layer is compared pairwise, constructing a judgment matrix to solve for the weights, and thus determining the subjective weights of the primary and secondary indicators.

[0046] Step S3: Establish a standardized matrix of indicator data using the entropy weight method, and determine the objective weights of primary and secondary indicators by calculating the entropy value and the difference coefficient.

[0047] The entropy in the entropy weight method represents the degree of disorder in information; the higher the degree of disorder, the lower the entropy. The entropy method is an objective weighting method; the greater the difference between indicators, the more information they can reflect, and the lower the entropy value. In this embodiment, for electromagnetic hybrid distribution network flexible interconnection devices, based on the established comprehensive evaluation index system, a standardized matrix of index data is established using the entropy weight method. The greater the difference between indicators, the more information they can reflect, and the lower the entropy value, thereby determining the objective weights of primary and secondary indicators.

[0048] Step S4: Determine the comprehensive weight by using the subjective and objective weights of the primary and secondary indicators.

[0049] The determination of the comprehensive weight is intended to improve the standardization of weighting and reduce the subjectivity of weighting. In this embodiment, the comprehensive weight of the primary and secondary indicators is calculated by combining the subjective weights of the primary and secondary indicators obtained using the analytic hierarchy process and the objective weights of the primary and secondary indicators obtained using the entropy weight method.

[0050] Step S5: Determine the set of evaluation factors and comments for the object to be evaluated, and construct the membership matrix of the primary and secondary indicators.

[0051] In this embodiment, the electromagnetic hybrid distribution network flexible interconnection device is taken as the object to be evaluated. As the set of factors affecting the object to be evaluated, the set of evaluation factors is essentially the established comprehensive evaluation index system. The set of comments refers to the set of possible evaluation levels. This method divides the evaluation levels into four levels: "poor", "average", "medium" and "good". Then the set of comments W = {W1, W2, W3, W4} = {poor, average, medium, good}.

[0052] The determination of the membership matrix involves calculating the membership level W for each secondary indicator. d The degree of hierarchical affiliation, and the level W to which each primary indicator belongs. d The membership degrees of the first-level and second-level indicators are obtained, where d = 1, 2, 3, 4.

[0053] Step S6: Combine the comprehensive weight with the membership matrix of the primary and secondary indicators to determine the evaluation level based on binary semantics.

[0054] Since different indicators contribute differently to the grade assessment, the combined weights of all primary and secondary indicators are represented in vector form. The weight vectors are then combined with the membership matrix using a weighted average composite operator to obtain the combined membership degree.

[0055] When the gaps between the evaluation index data corresponding to different evaluation levels are not equal, the evaluation results based on the principle of maximum membership may sometimes differ significantly from the actual situation. Therefore, to solve this problem, this method introduces level feature values ​​and combines them with binary semantics to determine the level. According to the judgment method of binary semantics, the level feature values ​​are first determined, then the level feature values ​​are further represented in matrix form, and finally the evaluation level is determined based on the related meanings of binary semantics.

[0056] The following section uses a certain electromagnetic hybrid distribution network flexible interconnection device as an example to further illustrate this method.

[0057] 1) Obtain the following experimental data, conduct analysis, and normalize the evaluation index data.

[0058] 2) The weights of all primary and secondary indicators are obtained based on the subjective hierarchical analysis method, the objective entropy weight method, and the combined weighting method.

[0059] 3) By conducting data analysis on different capability / component indicators, the hierarchical membership of the secondary evaluation indicators, primary evaluation indicators, and comprehensive membership degree are shown in Tables 1, 2, and 3 below.

[0060] Table 1. Membership Degrees of Each Secondary Evaluation Indicator

[0061]

[0062]

[0063] Table 2. Membership Degrees of Each Primary Evaluation Indicator

[0064]

[0065] Table 3. Membership Degree of Comprehensive Evaluation Indicators

[0066]

[0067] 4) Based on the binary semantic judgment method, the level is rated as "W3 (Medium)".

[0068] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0069] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0070] 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.

[0071] 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.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for evaluating the condition of a flexible interconnection device in an electromagnetic hybrid distribution network, characterized in that, Includes the following steps: Step S1: Construct a comprehensive evaluation index system for electromagnetic hybrid distribution network flexible interconnection devices. The comprehensive evaluation index system includes multiple primary indicators, and each primary indicator further includes multiple secondary indicators. Step S2: Establish a hierarchical structure model using the analytic hierarchy process (AHP), construct a judgment matrix using the established hierarchical structure model, and then determine the subjective weights of the primary and secondary indicators. Step S3: Establish a standardized matrix of indicator data using the entropy weight method, and determine the objective weights of primary and secondary indicators by calculating the entropy value and the difference coefficient; Step S4: Determine the comprehensive weight by combining the subjective and objective weights of the primary and secondary indicators; Step S5: Determine the set of evaluation factors and comments for the object to be evaluated, and construct the membership matrix of the primary and secondary indicators; Step S6: Combine the comprehensive weight with the membership matrix of the primary and secondary indicators, and determine the evaluation level based on binary semantics; In step S1, based on the multi-dimensional test results of the relevant components / capabilities of the electromagnetic hybrid distribution network flexible interconnection device, a secondary evaluation index system containing 30 secondary indicators is established. The secondary evaluation index system containing 30 secondary indicators further constitutes a primary evaluation index system containing 6 primary indicators, thereby obtaining a comprehensive evaluation index system for the electromagnetic hybrid distribution network flexible interconnection device. The six primary indicators are: insulation performance, short-circuit withstand performance, load performance, energy efficiency performance, self-protection performance, and voltage regulation performance. The insulation performance includes the following secondary indicators: equipment operating years, insulation within 2km of the surrounding area, body oil chromatography, bushing main insulation capacitance, body oil dielectric loss, body oil withstand voltage, body oil moisture content, on-load tap changer oil withstand voltage, winding insulation resistance, winding and bushing dielectric loss and bushing main insulation resistance. The short-circuit withstand performance includes the following secondary indicators: equipment service life, number of short-circuit impacts, winding frequency response, and low-voltage short-circuit impedance. The load performance includes the following secondary indicators: annual heavy overload duration, real-time oil temperature of the main transformer, offline body oil chromatography, online body oil chromatography, offline core grounding current, online core grounding current, and bushing oil chromatography. The energy efficiency performance includes the following secondary indicators: annual heavy overload duration, equipment operating years, no-load current and no-load loss, and no-load loss and energy efficiency. The self-protection performance includes the following secondary indicators: main body light gas and cooler failure and complete shutdown signal; The voltage regulation performance includes the following secondary indicators: on-load tap changer over-cycle risk and on-load tap changer operation count. In step S6, since different indicators contribute differently to the grade evaluation, the comprehensive weights of all first-level and second-level indicators are represented in vector form. The weight vectors are combined with the membership matrix using a weighted average composite operator to obtain the comprehensive membership. When the gaps between the evaluation index data corresponding to different evaluation levels are not equal, the evaluation results based on the principle of maximum membership may differ significantly from the actual situation. Therefore, level feature values ​​are introduced and combined with binary semantics to achieve level determination. According to the judgment method of binary semantics, the level feature values ​​are first determined, and then the level feature values ​​are further represented in matrix form. Finally, the evaluation level is determined based on the relevant meaning of binary semantics.

2. The method for evaluating the condition of an electromagnetic hybrid distribution network flexible interconnection device according to claim 1, characterized in that, In step S2, for electromagnetic hybrid distribution network flexible interconnection devices, based on the established comprehensive evaluation index system, the relationship between evaluation objectives, evaluation criteria and evaluation indicators is analyzed by the analytic hierarchy process (AHP), and a hierarchical structure model is established. The importance of the evaluation criteria layer and the evaluation indicator layer belonging to the same evaluation criteria layer are compared pairwise, and a judgment matrix is ​​constructed to solve for the weights, thereby determining the subjective weights of the first-level indicators and the second-level indicators.

3. The condition evaluation method for an electromagnetic hybrid distribution network flexible interconnection device according to claim 1, characterized in that, In step S3, for electromagnetic hybrid distribution network flexible interconnection devices, based on the established comprehensive evaluation index system, an index data standardization matrix is ​​established using the entropy weight method. The greater the difference between the indicators, the more information they can reflect, and the smaller the entropy value, thereby determining the objective weights of the primary and secondary indicators.

4. The condition evaluation method for an electromagnetic hybrid distribution network flexible interconnection device according to claim 1, characterized in that, In step S4, based on the subjective weights of the primary and secondary indicators obtained using the analytic hierarchy process and the objective weights of the primary and secondary indicators obtained using the entropy weighting method, the combined weights of the primary and secondary indicators are calculated using the combined weighting method.

5. The condition evaluation method for an electromagnetic hybrid distribution network flexible interconnection device according to claim 1, characterized in that, In step S5, the electromagnetic hybrid distribution network flexible interconnection device is taken as the object to be evaluated. The set of evaluation factors, representing the set of factors influencing the object to be evaluated, constitutes the established comprehensive evaluation index system. The set of comments represents the set of possible evaluation levels, which are divided into four levels: "poor," "average," "moderate," and "good." W = { W 1, W 2, W 3, W 4} = {Poor, Average, Moderate, Good}; Calculate the classification level of each secondary indicator W d The degree of hierarchical affiliation, and the level to which each primary indicator belongs. W d The membership degrees of the first-level and second-level indicators are obtained by finding the membership degree matrix of the first-level and second-level indicators, where d=1,2,3,4.

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