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

Abstract

The invention 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 to solve the problems that an existing evaluation index system for the overall operation state of a power transmission line is not perfect, and evaluation indexes are not comprehensive. And the accuracy of comprehensive evaluation is affected due to strong subjectivity of artificial participation in evaluation. A comprehensive index system is constructed, multi-dimensional indexes including safety, economy and the like are covered and divided into directional and quantitative indexes, inspection and online monitoring data are collected and preprocessed to ensure that the data are accurate and consistent, a fuzzification method and an improved analytic hierarchy process are used for determining weights, comprehensive evaluation is performed, and meanwhile, the comprehensive evaluation result is obtained. The method constructs an inspection data confidence model, considers the time interval and operation environment factors, calculates the confidence, finally synthesizes the data to calculate the evaluation value, determines the evaluation grade and key factors, provides a reliable basis for the operation and maintenance management of the power transmission line, and improves the operation stability of the power transmission line.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission and distribution, in particular to a power transmission line operation state comprehensive evaluation method based on an improved weighted evaluation model. BACKGROUND

[0002] As an important channel for transmitting electric energy in the power system, monitoring and evaluating the operation state of the power transmission line is crucial to maintaining the safe and stable operation of the power system. At present, there are corresponding industry standards for the evaluation of the operation state of the power transmission line. By constructing different state quantities of the power transmission line and specifying state grades, the evaluation result is obtained by scoring and calculating each state quantity according to the field measured data. This evaluation method is feasible and the evaluation result is relatively accurate, but it is highly subjective. With the continuous expansion of the power grid scale and the improvement of its intelligence, relying solely on industry standards cannot scientifically and comprehensively evaluate the operation state of the power transmission line.

[0003] For example, the patent with publication number CN111639844A discloses a power transmission line operation state comprehensive evaluation method, which includes the following steps: first, obtaining power transmission line inspection data; second, obtaining power transmission line online monitoring data and constructing a state evaluation index system; further, calculating the power transmission line state evaluation index weight and state evaluation result based on the online monitoring data; finally, constructing a model of the confidence of the power transmission line state evaluation result changing over time based on the inspection data, and calculating the comprehensive evaluation value of the power transmission line operation state considering the inspection data and the online monitoring data. However, the existing evaluation research on the overall operation state of the power transmission line is less, the evaluation index system is not perfect and the evaluation index is not comprehensive, mainly relying on manual participation, which has strong subjectivity and ignores the objectivity of the data, thereby affecting the accuracy of the comprehensive evaluation to some extent.

[0004] Therefore, a power transmission line operation state comprehensive evaluation method based on an improved weighted evaluation model is proposed. SUMMARY

[0005] The present application aims to provide a power transmission line operation state comprehensive evaluation method based on an improved weighted evaluation model, which aims to solve the problem of the existing evaluation index system for the overall operation state of the power transmission line being not perfect and the evaluation index being not comprehensive, and the strong subjectivity of the manual participation affecting the accuracy of the comprehensive evaluation in the above background technology.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solution: a power transmission line operation state comprehensive evaluation method based on an improved weighted evaluation model, which includes the following specific implementation steps:

[0007] S1, index system construction: determine the evaluation index of the transmission line operation state, and divide it into directional index and quantitative index;

[0008] S2, data collection and preprocessing: collect the inspection data and online monitoring data related to the evaluation index, and perform cleaning and standardization processing;

[0009] S3, index evaluation: define index set and evaluation set , generate evaluation matrix by fuzzy method, wherein element r ij represents the membership degree of index U i to grade A j ;

[0010] S4, weight setting and calculation: determine subjective weight by improved analytic hierarchy process; calculate objective weight based on index partition difference matrix; get comprehensive weight ω by weighted combination , wherein is adjustment parameter;

[0011] S5, comprehensive evaluation: combine evaluation matrix R and comprehensive weight ω to synthesize evaluation result vector , and quantitatively get comprehensive evaluation value;

[0012] S6, consider the confidence of inspection data: build a model of transmission line state evaluation result confidence changing with time based on inspection data, and calculate the confidence of inspection data according to the model;

[0013] S7, comprehensive evaluation: combine online monitoring data evaluation result and inspection data confidence to output transmission line operation state grade and key influencing factors.

[0014] Preferably, in step S2, the standardized method is used to convert index data of different dimensions into unified standard value, for positive index, the standardization formula is: ; for negative index, the standardization formula is: ; wherein x i is the original data of the i th index, y i is the standardized data.

[0015] Preferably, in step S4, the specific implementation of improved analytic hierarchy process to determine subjective weight includes:

[0016] Construct judgment matrix and calculate the product of each row element ;

[0017] M iThe open nth root is obtained , the subjective weight vector is obtained by normalization processing .

[0018] In the step S4, the index partition difference matrix is calculated to obtain the objective weight The specific implementation includes: selecting t partitions for the index set U, establishing a difference matrix , wherein is the barycentric value of the index set U i in the partition K;

[0019] The value of each U i is calculated by the inverse entropy formula , wherein to determine the objective weight vector ;

[0020] The final comprehensive weight is determined.

[0021] In the step S5, the comprehensive evaluation is performed as follows:

[0022] S51: the evaluation matrix R is calculated, the index set U to be evaluated, the evaluation set A, and the partition t are determined, and the n x m-dimensional evaluation matrix of the whole network and each partition is listed;

[0023] S52: the difference matrix D is calculated, the barycentic value vector of all row vectors of the evaluation matrix of each partition is calculated, and the n x m-dimensional difference matrix is obtained;

[0024] S53: the weight vector ω is set, and the weight setting method in the above step S4 is calculated;

[0025] S54: the evaluation result is synthesized, , wherein is the evaluation vector of the index set U in the whole network range;

[0026] S55: the above evaluation result is calculated by using the comprehensive quantification formula to obtain the comprehensive quantification result.

[0027] In the step S55, the comprehensive quantification formula is , wherein is the quantified evaluation level.

[0028] In the index evaluation method, when the evaluation set is quantified, the descriptive evaluation level is converted into a value 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”.

[0029] In the step S6, the specific implementation steps of considering the confidence of the inspection data are as follows:​

[0030] S61: obtaining a time t1 of a previous inspection on the power transmission line, an inspection time interval T, and a power transmission line state evaluation result based on inspection data;

[0031] S62: constructing a model of confidence of the power transmission line state evaluation result based on the inspection data changing over time, the confidence model taking into account the inspection time interval T and an operation environment E factor of the power transmission line.

[0032] S63: calculating the confidence of the inspection data according to the confidence model.

[0033] Preferably, the calculation formula of the confidence model is where C is the confidence, t2 is the current time, σ is a parameter related to time decay, is a function related to the operation environment factor,

[0034] Preferably, when the operation environment factor E is quantified as a numerical value, the better the operation environment, the greater the value of E, defined as: , where is the maximum value of the operation environment factor.

[0035] Compared with the prior art, the power transmission line operation state comprehensive evaluation method based on the improved weighted evaluation model has the following beneficial effects:

[0036] The power transmission line operation state comprehensive evaluation method based on the improved weighted evaluation model can more accurately reflect the operation state of the power transmission line by constructing a comprehensive index system covering multiple dimensions such as safety, economy, quality, cleanliness, externality, power supply reliability and intelligent level, determining the subjective weight by using the improved analytic hierarchy process, determining the objective weight by combining the difference matrix and calculating the anti-entropy based on the partition, and then obtaining the comprehensive weight, so that the determination of the weight is more reasonable and the accuracy of the evaluation is improved; at the same time, the inspection data and online monitoring data are collected and preprocessed to ensure the accuracy and consistency of the data, and by comprehensively considering the evaluation result of the online monitoring data and the confidence of the inspection data, the operation state of the power transmission line can be more comprehensively evaluated to provide a more scientific basis for operation and maintenance management; in addition, the method can also find out the key factors affecting the operation state, which is helpful for formulating targeted improvement measures to improve the reliability and stability of the power transmission line. BRIEF DESCRIPTION OF DRAWINGS

[0037] Fig. 1 is the overall flowchart of the present application;

[0038] Fig. 2 is the index system classification architecture diagram of the present application. DETAILED DESCRIPTION

[0039] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of the present application.

[0040] In order to solve the problems that the existing evaluation index system for the overall operation state of the power transmission line is not perfect and the evaluation indexes are not comprehensive, and the subjectivity of the manual participation evaluation affects the accuracy of the comprehensive evaluation, please refer to Figs. 1-2 , the following preferred technical solutions are provided:

[0041] The comprehensive evaluation method for the operation state of the power transmission line based on the improved weighted evaluation model comprises the following specific implementation steps:

[0042] Step 1: Construction of index system

[0043] According to the actual demand, the evaluation indexes of the operation state of the power transmission line are determined exactly, which cover multiple dimensions such as safety, economy, quality, cleanliness, externality, power supply reliability and intelligent level, and are divided into directional indexes and quantitative indexes.

[0044] The directional indexes include two aspects of externality and safety. The externality specifically includes policies and regulations, rules and regulations, and double-carbon related policies; the safety specifically includes monitoring and early warning (only providing data support for the calculation of "fault state", not compared with other indexes), maintenance and backup, base 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] The quantitative indicators include economy, quality, power supply reliability, cleanliness, and intelligent level, etc. Among them, economy specifically covers equipment light load rate, high-voltage transmission network loss rate, monthly power generation plan deviation rate, unit power purchase cost, average coal consumption for power generation, and average coal consumption for power supply, etc.; quality includes frequency-related indicators (system frequency, power grid maximum / minimum frequency, CPS1, CPS2, responsible frequency over-limit operation time, responsible frequency qualified rate, primary frequency modulation operation rate, primary frequency modulation power, AGC instruction regulation performance, AGC regulation rate, etc.) and voltage quality-related indicators (main grid voltage qualified rate, comprehensive voltage qualified rate, central point voltage qualified rate, voltage unqualified plant station situation, voltage fluctuation rate, AVC average operation rate, etc.); power supply reliability includes power supply reliability rate, overload rate, average power outage time, user power outage times, fault average power outage proportion, and switch device failure rate, etc.; cleanliness includes clean energy use-related indicators and multi-layer indicators related to flue gas emission compliance; intelligent level includes communication technology, communication application range, technology maturity, and demand response level, etc.

[0046] Step two: data collection and preprocessing

[0047] Collecting comprehensive inspection data and online monitoring data closely related to selected indicators.

[0048] Carefully cleaning and preprocessing the collected data to ensure the accuracy and consistency of the data.

[0049] Using standardization method to convert different dimension indicator data into unified standard value. For positive indicators, the standardization formula is: ; for negative indicators, the standardization formula is: ; where x i represents the original data of the i-th indicator, y i is the standardized data.

[0050] Step three: indicator evaluation

[0051] Explicitly defining and evaluation set , and calculating evaluation matrix in a fuzzy way, where r ij represents the membership degree of indicator U i to level A j .

[0052] Step four: weight setting and calculation

[0053] Using improved analytic hierarchy process to determine subjective weight, which specifically includes constructing hierarchical structure, constructing judgment matrix, and calculating , Mi The open n-th root is obtained, and the subjective weight vector is obtained by normalization .

[0054] At the same time, t partitions are selected from the index set U, and a difference matrix is established , wherein is the U i The center of gravity value of the partition K is calculated, and the anti-entropy of each U i is calculated. , wherein , so as to determine the objective weight vector .

[0055] Finally, the comprehensive weight is determined , wherein is a parameter for adjusting the relative importance of subjective weight and objective weight, which is a constant in the interval of 0 to 1.

[0056] Step five: comprehensive evaluation

[0057] S51, first, determine the index set U to obtain 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.

[0058] S52, then, the difference matrix D is calculated, the center of gravity vector of all row vectors of the partition evaluation matrix is calculated, and the n×m-dimensional difference matrix is obtained.

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

[0060] S54, the evaluation result is synthesized, , wherein is the evaluation vector of the index set U in the whole network range.

[0061] S55, finally, the above evaluation result is calculated by using the comprehensive quantification formula, and the comprehensive quantification result is obtained. The comprehensive quantification formula is , wherein is the quantified evaluation level.

[0062] When the index evaluation method quantifies the evaluation set, the descriptive evaluation level is converted into a value 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”.

[0063] Step six: considering the confidence of the inspection data

[0064] S61, 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 are obtained.

[0065] S62, a model of confidence of the transmission line state evaluation result based on the inspection data changing over time is constructed, and the confidence model fully considers the inspection time interval T and the operation environment E factor of the transmission line.

[0066] S63, the confidence of the inspection data is calculated according to the confidence model. The calculation formula of the confidence model is , wherein C represents the confidence, t2 is the current time, σ is a parameter related to time decay, and is a function related to the operation environment factor. When the operation environment factor E is quantified as a numerical value, the better the operation environment, the larger the value of E, and is defined as: , wherein is the maximum value of the operation environment factor.

[0067] Step seven: comprehensive evaluation

[0068] The transmission line operation state comprehensive evaluation value considering the inspection data and the online monitoring data is calculated by comprehensively considering the evaluation result of the online monitoring data and the confidence of the inspection data.

[0069] The evaluation result is analyzed in depth to determine the evaluation level to which the transmission line operation state belongs, and the key factors affecting the operation state are accurately found out.

[0070] Specifically, first, according to the actual demand, an index system is constructed, and indexes including safety, economy, quality, cleanliness, externality, power supply reliability, and intelligent level are determined, and are divided into directional indexes and quantitative indexes. Then, the inspection data and the online monitoring data are collected and preprocessed, and the standardized method is used to convert the data of different dimensions into a unified standard value. Next, the index set and the evaluation set are defined, the evaluation matrix is calculated by using the fuzzy method to evaluate the indexes. Then, the subjective weight is determined by using the improved analytic hierarchy process, the difference matrix is established for the index set, and the anti-entropy is calculated to determine the objective weight, and then the comprehensive weight is obtained. In the comprehensive evaluation, the evaluation matrix and the difference matrix are calculated first, the weight vector is set, the evaluation result is synthesized and quantified. At the same time, considering the confidence of the inspection data, a model of confidence changing over time is constructed, which considers the inspection time interval and the operation environment factor, and the confidence is calculated according to the model. Finally, the transmission line operation state comprehensive evaluation value is calculated by comprehensively considering the online monitoring data evaluation result and the inspection data confidence, and the evaluation result is analyzed to determine the evaluation level and find out the key factors.

[0071] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and implementations, it is to be understood that the terminology used is for the purpose of descriptive clarity and that it is intended to be limited only by the words recited in the appended claims. It is to be understood that the terms such as first and second, etc., merely are used to differentiate one from another without necessarily implying or requiring any actual relationship or order between them. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0072] While the embodiments of the application have been shown and described herein, it is to be understood that the application is not limited to these embodiments and that various changes, modifications, substitutions and alterations can be made thereto without departing from the spirit and scope of the inventive concepts disclosed herein. The scope of the application is limited only by the claims and the equivalents thereof.

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; 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; 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 level and the 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 ; M i The nth root of opening , the subjective weight vector is obtained by normalizing .​ 4. The method for comprehensive evaluation of the operating state of a power transmission line based on an improved weighted evaluation model according to claim 3, characterized in that: In the step S4, the index partition difference matrix calculates the objective weight The specific implementation includes: selecting t partitions for the index set U, establishing a difference matrix Wherein U i The barycentric value of the partition K; By the reverse entropy formula computing the values of each U i , wherein to determine the objective weight vector ; Finalizing the combined weight .

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: 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 step S4; S54: synthesis evaluation results, wherein is the 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.

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 5, characterized in that: The comprehensive quantization formula in the step S55 is wherein is the quantized evaluation level.

7. The method of claim 5, wherein the method further comprises: When the index evaluation method quantitatively processes the evaluation set, the descriptive evaluation level is converted into a value 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".

8. 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 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.

9. The method for comprehensive evaluation of the operating state of a power transmission line based on an improved weighted evaluation model according to claim 8, characterized in that: The calculation formula of the confidence model is where 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.

10. The method for comprehensive evaluation of the operating state of a power transmission line based on an improved weighted evaluation model according to claim 9, characterized in that: 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.

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