Power transmission line operation state comprehensive evaluation method based on improved weighted evaluation model

Abstract

The application provides a power transmission line operation state comprehensive evaluation method based on an improved weighted evaluation model, belongs to the technical field of power transmission and distribution, and aims at solving the problems of an imperfect evaluation index system and insufficient comprehensive evaluation indexes of the overall operation state of a power transmission line, strong subjectivity of manual participation in evaluation and influence of the accuracy of comprehensive evaluation, and the like, builds a comprehensive index system, covers multidimensional indexes such as safety and economy, and is divided into directional and quantitative indexes, collects inspection and online monitoring data, pre-processes the data to ensure the accuracy and consistency of the data, determines the weight by using a fuzzification method and an improved analytic hierarchy process, performs comprehensive evaluation, meanwhile, a confidence degree model of the inspection data is built, time intervals and operation environment factors are considered, the confidence degree is calculated, the evaluation value is finally calculated based on the comprehensive data, the evaluation grade and key factors are determined, a reliable basis is provided for operation and maintenance management of the power transmission line, and the operation stability of the power transmission line is improved.

Description

Technical Field

[0001] This invention relates to the field of power transmission and distribution technology, and more specifically, to a comprehensive evaluation method for the operating status of power transmission lines based on an improved weighted evaluation model. Background Technology

[0002] As a crucial channel for transmitting electrical energy in the power system, monitoring and evaluating the operational status of transmission lines is essential for maintaining the safe and stable operation of the power system. Currently, there are corresponding industry standards for assessing the operational status of transmission lines. These standards involve constructing different state variables for the transmission lines and defining state levels. The evaluation results are obtained by scoring each state variable based on field measurement data. This assessment method is feasible and yields relatively accurate results, but it is highly subjective. With the continuous expansion of the power grid and its increasing intelligence, relying solely on industry standards is no longer sufficient for a scientific and comprehensive assessment of the operational status of transmission lines.

[0003] For example, patent CN111639844A discloses a comprehensive evaluation method for the operating status of transmission lines, including the following steps: First, acquiring transmission line inspection data; second, acquiring transmission line online monitoring data and constructing a status evaluation index system; further, calculating the weights of transmission line status evaluation indicators and status evaluation results based on online monitoring data; finally, constructing a model of the confidence level of transmission line status evaluation results based on inspection data changing over time, and calculating the comprehensive evaluation value of transmission line operating status considering both inspection data and online monitoring data. However, existing research on the overall operating status evaluation of transmission lines is limited, the evaluation index system is incomplete and the evaluation indicators are not comprehensive enough, and it mainly relies on manual participation, which is highly subjective and ignores the objectivity of the data, thus affecting the accuracy of the comprehensive evaluation to a certain extent.

[0004] Therefore, a comprehensive evaluation method for the operating status of transmission lines based on an improved weighted evaluation model is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a comprehensive evaluation method for the operating status of transmission lines based on an improved weighted evaluation model. This method aims to address the problems in the background art, where the existing evaluation index system for the overall operating status of transmission lines is not perfect and the evaluation indexes are not comprehensive enough. Furthermore, the reliance on manual evaluation leads to strong subjectivity, which affects the accuracy of the comprehensive evaluation.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a comprehensive evaluation method for the operating status of transmission lines based on an improved weighted evaluation model, wherein the comprehensive evaluation method includes the following specific implementation steps:

[0007] S1. Construction of the indicator system: Determine the evaluation indicators for the operating status of transmission lines and divide them into directional indicators and quantitative indicators;

[0008] S2. Data collection and preprocessing: Collect inspection data and online monitoring data related to the evaluation indicators, and perform cleaning and standardization processing;

[0009] S3. Indicator Evaluation: Defining the Indicator Set and the set of judgments The evaluation matrix is ​​generated by fuzzification. , where element r ij Indicator U i For level A j Membership degree;

[0010] S4. Weight Setting and Calculation: Subjective weights are determined using an improved analytic hierarchy process. ; Calculate objective weights based on the indicator partition difference matrix Through weighted combination The overall weight ω is obtained, where To adjust the parameters;

[0011] S5. Comprehensive Evaluation: Combine the evaluation matrix R and the comprehensive weight ω to synthesize the evaluation result vector. And quantify to obtain a comprehensive evaluation value;

[0012] S6. Consider the confidence level of inspection data: Construct a model of the change in confidence level of transmission line status assessment results over time based on inspection data, and calculate the confidence level of inspection data according to the model;

[0013] S7. Comprehensive Assessment: Based on the comprehensive assessment results of online monitoring data and the confidence level of inspection data, output the operating status level of transmission lines and key influencing factors.

[0014] Preferably, in step S2, a standardization method is used to convert index data with different dimensions into unified standard values. For positive indicators, the standardization formula is: For negative indicators, the standardized formula is: ;where x i Let y be the raw data for the i-th indicator. i This is the standardized data.

[0015] Preferably, in step S4, the improved analytic hierarchy process is used to determine the subjective weights. The specific implementation includes:

[0016] Construct a judgment matrix and calculate the product of elements in each row. ;

[0017] For M iTaking the nth root yields ,right Normalization process yields the subjective weight vector .

[0018] Preferably, in step S4, the objective weights are calculated from the indicator partition difference matrix. The specific implementation includes: selecting t partitions from the indicator set U and establishing a difference matrix. ,in For U i The centroid value of partition K;

[0019] Using the anti-entropy formula Calculate each U i The value of , where In order to determine the objective weight vector ;

[0020] Final determination of overall weight .

[0021] Preferably, in step S5, the comprehensive evaluation step is as follows:

[0022] S51: Find the evaluation matrix R, determine the set of indicators to be evaluated U, the evaluation set A and the partition t, and list the n×m dimension evaluation matrix of the whole network and each partition;

[0023] S52: Find the difference matrix D, calculate the centroid value vector of all row vectors of the evaluation matrix of each partition, and obtain the n×m dimension difference matrix;

[0024] S53: Set the weight vector ω, calculated according to the weight setting method in step S4 above;

[0025] S54: Composite evaluation results ,in Let U be the evaluation vector of the indicator set U across the entire network.

[0026] S55: The above evaluation results are calculated using a comprehensive quantitative formula to obtain the comprehensive quantitative result.

[0027] Preferably, the comprehensive quantization formula in step S55 is as follows: ,in This refers to the quantified evaluation level.

[0028] Preferably, when the indicator evaluation method quantifies the evaluation set, it converts the descriptive evaluation level into a value between 0 and 1, specifically as follows: "Good - 0.7", "Average - 0.5", "Poor - 0.3" and "Very Poor - 0.1".

[0029] Preferably, in step S6, the specific implementation steps for considering the confidence level of the inspection data are as follows:

[0030] S61: Obtain the time t1 of a single inspection on the transmission line to be evaluated, the inspection time interval T, and the transmission line status evaluation results based on the inspection data;

[0031] S62: Construct a model for the change of confidence level of transmission line condition assessment results over time based on inspection data. This confidence level model considers the inspection time interval T and the operating environment E of the transmission line.

[0032] S63: Calculate the confidence level of the inspection data based on the confidence level model.

[0033] Preferably, the calculation formula for the confidence model is as follows: Where C is the confidence level, t2 is the current time, and σ is a parameter related to time decay. It is a function related to operating environment factors.

[0034] Preferably, when the operating environment factor E is quantified into a single value, the better the operating environment, the larger the value of E. Defined as: , This represents the maximum value of the operating environment factors.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] This invention proposes a comprehensive evaluation method for the operating status of transmission lines based on an improved weighted evaluation model. By constructing a comprehensive index system covering multiple dimensions such as safety, economy, quality, cleanliness, externalities, power supply reliability, and intelligence level, it can more accurately reflect the operating status of transmission lines. An improved analytic hierarchy process (AHP) is used to determine subjective weights, while objective weights are determined by establishing a difference matrix through partitioning and calculating inverse entropy, thus obtaining a comprehensive weight. This makes the weight determination more reasonable and improves the accuracy of the evaluation. Simultaneously, the collection and preprocessing of inspection and online monitoring data ensures data accuracy and consistency. By comprehensively considering the evaluation results of online monitoring data and the confidence level of inspection data, a more comprehensive assessment of the operating status of transmission lines can be achieved, providing a more scientific basis for operation and maintenance management. Furthermore, this method can identify key factors affecting the operating status, helping to formulate targeted improvement measures and enhance the reliability and stability of transmission lines. Attached Figure Description

[0037] Figure 1 This is an overall flowchart of the present invention;

[0038] Figure 2 This is a classification architecture diagram of the indicator system of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0040] To address the shortcomings of existing assessment index systems for the overall operational status of transmission lines, such as inadequacy of the existing indexes and insufficient comprehensiveness, as well as the inherent subjectivity of manual evaluation affecting the accuracy of comprehensive assessments, please refer to [link to relevant documentation]. Figures 1-2 The following preferred technical solutions are provided:

[0041] A comprehensive evaluation method for the operating status of transmission lines based on an improved weighted evaluation model includes the following specific implementation steps:

[0042] Step 1: Constructing the Indicator System

[0043] Based on actual needs, the evaluation indicators for the operation status of transmission lines are precisely determined. These indicators cover multiple dimensions such as safety, economy, quality, cleanliness, externality, power supply reliability, and intelligence level, and are further divided into directional indicators and quantitative indicators.

[0044] The directional indicators include two aspects: externalities and security. Externalities specifically include policies and regulations, rules and regulations, and carbon-related policies; security specifically includes monitoring and early warning (which only provides data support for the calculation of "fault state" and is not listed alongside other indicators), maintenance and standby, ground state (static security analysis), fault state (static security analysis), and dynamic security analysis (including small disturbance stability, transient power angle stability, transient frequency stability, transient voltage stability, etc.).

[0045] Quantitative indicators include economic efficiency, quality, power supply reliability, cleanliness, and intelligence level. Economic efficiency specifically covers equipment light load rate, high-voltage transmission network loss rate, monthly power generation plan deviation rate, unit electricity purchase cost, average coal consumption for power generation, and average coal consumption for power supply. Quality includes frequency-related indicators (system frequency, grid maximum / low frequency, CPS1, CPS2, over-limit operation time of the responsible frequency, responsible frequency qualification rate, primary frequency regulation commissioning rate, primary frequency regulation power consumption, AGC command regulation performance, AGC regulation rate, etc.) and voltage quality-related indicators (main grid voltage qualification rate, comprehensive voltage qualification rate, central point voltage qualification rate, voltage non-compliant substation conditions, voltage fluctuation rate, average AGC commissioning rate, etc.). Power supply reliability includes power supply reliability rate, overload rate, average outage time, number of user outages, average outage ratio due to faults, and switchgear failure rate. Cleanliness includes multiple aspects of clean energy use-related indicators and flue gas emission compliance indicators. Intelligence level includes communication technology, communication application scope, technology maturity, and demand response level.

[0046] Step 2: Data Collection and Preprocessing

[0047] Comprehensive collection of inspection data and online monitoring data, which are closely related to the selected indicators.

[0048] The collected data undergoes careful cleaning and preprocessing to ensure its accuracy and consistency.

[0049] Standardization methods are used to convert indicator data with different dimensions into unified standard values. For positive indicators, the standardization formula is: For negative indicators, the standardized formula is: ;where x i Let y represent the raw data for the i-th indicator. i This is the standardized data.

[0050] Step 3: Indicator Evaluation

[0051] Clearly define and the set of judgments The evaluation matrix is ​​calculated using fuzzification. , where r ij Indicator U i For level A j The degree of subordination.

[0052] Step 4: Weight Setting and Calculation

[0053] The improved analytic hierarchy process is used to determine subjective weights, specifically including constructing a hierarchical structure, building a judgment matrix, and multiplying the elements in each row. Mi The subjective weight vector is obtained by taking the nth root and then normalizing it. .

[0054] Simultaneously, t partitions are selected for the indicator set U to establish a difference matrix. ,in For U i Calculate each U at the centroid value of partition K. i anti-entropy ,in In order to determine the objective weight vector .

[0055] Finally, the overall weight was determined. ,in The parameter is used to adjust the relative importance of subjective and objective weights, and is specifically a constant in the range of 0 to 1.

[0056] Step 5: Comprehensive Evaluation

[0057] S51. First, determine the indicator set to obtain the evaluation matrix R, determine the indicator set U, the judgment set A, and the partition t, and list the n×m dimension evaluation matrix of the whole network and each partition.

[0058] S52. Next, obtain the difference matrix D, calculate the centroid value vector of all row vectors of the evaluation matrix of each partition, and obtain the n×m dimensional difference matrix.

[0059] S53. Then, set the weight vector ω and calculate it according to the weight setting method in step S4 above.

[0060] S54. Re-synthesize the evaluation results. ,in Let be the evaluation vector of the indicator set U across the entire network.

[0061] S55. Finally, the above evaluation results are calculated using the comprehensive quantitative formula to obtain the comprehensive quantitative result. The comprehensive quantitative formula is as follows: ,in This refers to the quantified evaluation level.

[0062] When the indicator evaluation method quantifies the evaluation set, it converts the descriptive evaluation level into a value between 0 and 1, specifically as follows: "Good - 0.7", "Average - 0.5", "Poor - 0.3" and "Very Poor - 0.1".

[0063] Step Six: Consider the confidence level of the inspection data

[0064] S61. Obtain the time t1 of a single inspection on the transmission line to be evaluated, the inspection time interval T, and the transmission line status evaluation results based on the inspection data.

[0065] S62. Construct a model for the change of confidence level of transmission line status assessment results over time based on inspection data. This confidence level model fully considers the inspection time interval T and the operating environment E of the transmission line.

[0066] S63. Calculate the confidence level of the inspection data based on the confidence level model. The formula for calculating the confidence level model is as follows: Where C represents the confidence level, t2 is the current time, and σ is a parameter related to time decay, which is a function related to operating environment factors. When the operating environment factor E is quantified into a numerical value, the better the operating environment, the larger the value of E, defined as: ,in It is the maximum value of the operating environment factors.

[0067] Step Seven: Comprehensive Assessment

[0068] Taking into account both the evaluation results of online monitoring data and the confidence level of inspection data, a comprehensive evaluation value of the transmission line operating status is calculated.

[0069] The evaluation results were analyzed in depth to determine the rating level of the transmission line's operating status and to accurately identify the key factors affecting the operating status.

[0070] Specifically, firstly, an indicator system is constructed based on actual needs, defining indicators including dimensions such as safety, economy, quality, cleanliness, externalities, power supply reliability, and intelligence level, categorized into directional and quantitative indicators. Next, inspection and online monitoring data are collected and preprocessed, using standardization methods to convert data of different dimensions into unified standard values. Then, by defining indicator sets and evaluation sets, an evaluation matrix is ​​calculated using fuzzy methods for indicator evaluation. Subsequently, an improved analytic hierarchy process (AHP) is used to determine subjective weights, and a difference matrix is ​​established by partitioning the indicator set and calculating inverse entropy to determine objective weights, thus obtaining a comprehensive weight. In the comprehensive evaluation, the evaluation matrix and difference matrix are first calculated, a weight vector is set, and the evaluation results are synthesized and quantified. Simultaneously, considering the confidence level of inspection data, a model is constructed to show how confidence level changes over time, taking into account inspection intervals and operating environment factors; the confidence level is calculated based on the model. Finally, by combining the evaluation results of online monitoring data and the confidence level of inspection data, a comprehensive evaluation value for the transmission line's operating status is calculated, and the evaluation results are analyzed to determine the rating level and identify key factors.

[0071] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0072] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for comprehensive evaluation of the operating state of a power transmission line based on an improved weighted evaluation model, characterized in that, The comprehensive evaluation method comprises the following specific implementation steps: S1, index system construction: determine the evaluation indexes of the transmission line operation state, and divide them into directional indexes and quantitative indexes; S2, data collection and preprocessing: collect the inspection data and online monitoring data related to the evaluation indexes, and perform cleaning and standardization processing; S3, Index evaluation: define index set and evaluation set , generate evaluation matrix by fuzzy method , where element r ij represents the membership degree of index U i to grade A j ; S4, weight setting and calculation: improved analytic hierarchy process is used to determine subjective weight ; calculating objective weights based on index partition difference matrix ; by weighted combination to obtain the comprehensive weight ω, wherein is an adjustment parameter; In the step S4, the index partition difference matrix is used to calculate the objective weight The specific implementation includes: selecting t partitions for the index set U, and establishing a difference matrix , which In For U i The center of gravity value of the partition K; By the reverse entropy formula The values of each U i are calculated, where to determine the objective weight vector ; Finalizing the integrated weight ; S5, comprehensive evaluation: combining the evaluation matrix R and the comprehensive weight ω, the synthesized evaluation result vector is obtained and the quantitative comprehensive evaluation value is obtained. S6, considering the confidence of the inspection data: constructing a model of the confidence of the transmission line state evaluation result based on the inspection data changing with time, and calculating the confidence of the inspection data according to the model; The calculation formula of the confidence model is Wherein C is the confidence, t2 is the current time, σ is a parameter related to time decay, is a function related to the running environment factor, when the running environment factor E is quantified as a numerical value, the better the running environment, the greater the value of E, is defined as: , Wherein is the maximum value of the running environment factor; S7, comprehensive evaluation: comprehensively evaluating the online monitoring data evaluation result and the confidence of the inspection data, and outputting the transmission line operation state grade and key influencing factors.

2. The power transmission line operation state comprehensive evaluation method based on the improved weighted evaluation model according to claim 1, characterized in that: In the step S2, the index data of different dimensions are converted into unified standard values by using a standardization method. For a positive index, the standardization formula is: ; For negative indicators, the standardization formula is: ; where x i is the raw data of the ith indicator, y i is the standardized data.

3. The method for comprehensive evaluation of the operating state of a power transmission line based on an improved weighted evaluation model according to claim 1, characterized in that: In the step S4, the improved analytic hierarchy process determines the subjective weight The specific implementation includes: Constructing the judgment matrix and calculating the product of the elements of each row ; For M i Taking the nth root yields ,right Normalization process yields the subjective weight vector .

4. The power transmission line operation state comprehensive evaluation method based on the improved weighted evaluation model according to claim 1, characterized in that: In the step S5, the steps of the comprehensive evaluation are as follows: S51: calculate the evaluation matrix R, determine the index set U to be evaluated, the evaluation set A and the partition t, and list the n*m-dimensional evaluation matrix of the whole network and each partition; S52: calculate the difference matrix D, calculate the barycentric value vector of all row vectors of each partition evaluation matrix, and obtain the n*m-dimensional difference matrix; S53: set the weight vector ω, and calculate according to the weight setting method in the above S4 step; S54: synthesis evaluation results, wherein is an evaluation vector of the index set U in the whole network range; S55: calculate the above evaluation result by using the comprehensive quantification formula to obtain the comprehensive quantification result.

5. The method for comprehensive evaluation of the operating state of a power transmission line based on an improved weighted evaluation model according to claim 4, characterized in that: The comprehensive quantization formula in the step S55 is wherein is the quantized evaluation level.

6. The method for comprehensive evaluation of the operating state of a power transmission line based on an improved weighted evaluation model according to claim 4, characterized in that: When the index evaluation method quantitatively processes the evaluation set, the descriptive evaluation grades are converted into values between 0 and 1, and the specific method is as follows: "good-0.7", "general-0.5", "poor-0.3" and "very poor-0.1".

7. The method of claim 1, wherein the method is characterized by: In the step S6, the specific implementation steps of considering the confidence of the inspection data are as follows: S61: obtain the time t1 of the last inspection on the transmission line to be evaluated, the inspection time interval T and the transmission line state evaluation result based on the inspection data; S62: construct a model of the confidence of the transmission line state evaluation result based on the inspection data changing with time, which considers the inspection time interval T and the operation environment E factor of the transmission line; S63: calculate the confidence of the inspection data according to the confidence model.

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