CN108764659A - A kind of distribution network reliability analysis of Influential Factors method based on Fuzzy Comprehensive Method - Google Patents

Abstract

The present invention provides a fuzzy synthesis method-based analysis method for influencing factors of distribution network reliability. By establishing a comprehensive evaluation index system for influencing factors of distribution network power supply reliability, a fuzzy synthesis method is used to analyze distribution network power supply reliability influencing factors. Based on the comprehensive evaluation model, the goal of analyzing the power supply reliability of the distribution network can be achieved in a more accurate way, and it can provide guidance for the planning of the distribution network. By determining the main factor sets that affect the reliability of distribution network power supply, the method first uses the Analytic Hierarchy Process (AHP) to stratify the factor sets, constructs a comparative judgment matrix, completes the hierarchical single sorting and total sorting, and then passes the consistency test. Determine the weight of each indicator. At the same time, on this basis, use the fuzzy comprehensive method to fuzzy score each single index, determine the degree of correlation between the reliability of power supply and various influencing factors, and finally obtain a comprehensive evaluation of the reliability of the distribution network.

Description

An Analysis Method of Distribution Network Reliability Affecting Factors Based on Fuzzy Synthesis Method

technical field

The invention relates to the technical field of optimizing and sorting factors affecting power supply reliability of distribution networks, in particular to a method for analyzing factors affecting reliability of distribution networks based on a fuzzy synthesis method.

Background technique

With the advancement of social economy and technology, the reliability of the distribution network is also increasing, the output value of each unit of electricity for users is increasing, and the economic losses caused by unit power outages to users and society are increasing. The requirements for power supply reliability are getting higher and higher. Therefore, it is necessary to analyze the reliability factors of distribution network power supply to find out the factors that have a greater impact on user-side faults and power outages, so as to facilitate the planning and transformation of distribution network.

Factors affecting power supply reliability of distribution network mainly include external factors and internal factors. External factors mainly include natural environment and external force damage factors. Internal factors mainly include grid structure, equipment level, distribution automation level and management level factors. Among them, the grid structure refers to the wiring mode of the distribution network. The wiring modes mainly include radiation type, ring type, segmented connection type and standby type connection; the natural environment refers to factors such as the weather conditions and geographical location of the distribution network; External force damage factors mainly include human responsibility (caused by factors such as vehicle damage, construction, and theft) and sundries (caused by factors such as wedding ribbons, kites, and bird's nests); the level of equipment equipment refers to the degree of insulation and aging of equipment; the level of power distribution automation Refers to the on-line rate of switches with telemetry, remote signaling or remote control functions; management level refers to the rate of equipment condition maintenance and live work. There are many factors affecting the reliability of distribution network power supply. When calculating the reliability of distribution network power supply, only the main influencing factors are often considered, and the secondary or negligible influencing factors are ignored to facilitate reliability calculation and analysis. However, when analyzing the reliability of distribution network power supply, it is often difficult to directly provide an accurate analytical model of the correlation between influencing factors and reliability indicators, so it is ambiguous.

At present, the fuzzy comprehensive method is used to analyze the correlation degree model between the reliability of distribution network and its influencing factors. The fuzzy synthesis method transforms qualitative evaluation into quantitative evaluation according to the membership degree theory of fuzzy mathematics, that is, uses fuzzy mathematics to make an overall evaluation of things or objects restricted by various factors. It has the characteristics of clear results and strong system. It can better solve fuzzy and difficult-to-quantify problems, and is suitable for solving various non-deterministic problems. It is an effective method to correlate with its influencing factors.

Contents of the invention

The technical problem to be solved by the present invention is to provide a fuzzy comprehensive method based on the distribution network reliability influencing factor analysis method, to achieve the goal of analyzing the power supply reliability of the distribution network in a more accurate way, and to provide Planning provides guidance.

The described method for analyzing factors affecting distribution network reliability based on fuzzy synthesis method comprises the following steps:

Determine the main factor set that affects the power supply reliability of the distribution network, and stratify the factor set according to the analytic hierarchy process. The judgment matrix of the upper-level evaluation index completes single-level sorting, total-level sorting and consistency verification, obtains the weight of each index in each level of evaluation indicators, and uses the fuzzy synthesis method to conduct an overall evaluation of the factors affecting the reliability of distribution network power supply. Then determine the degree of correlation between power supply reliability and various influencing factors, and provide guidance for distribution network planning.

The reliability of distribution network power supply is affected by many factors, such as grid structure, natural environment, external force damage, equipment level, distribution automation level, management level factors, etc. It is difficult to directly give the correlation degree between the influencing factors and reliability indicators The model is parsed precisely and therefore has ambiguity. Therefore, the present invention introduces a fuzzy processing method, and uses a fuzzy synthesis method to determine the degree of correlation between power supply reliability and various influencing factors, that is, to determine the weight of each reliability influencing factor. By constructing a comparative judgment matrix, complete the hierarchical single sorting and total sorting, and then pass the consistency test to finally determine the weight of each index. At the same time, on this basis, each single index is fuzzy scored, and finally a comprehensive evaluation of the reliability of the distribution network is obtained.

Description of drawings

Fig. 1 is a schematic flow chart of a method for analyzing factors affecting distribution network reliability based on fuzzy synthesis method in the present invention, and Fig. 2 is a hierarchical structure diagram for calculating weights by analytic hierarchy process.

A method for analyzing factors affecting distribution network reliability based on fuzzy comprehensive method of the present invention comprises the following steps:

S1, determine the set of main factors affecting the reliability of distribution network power supply;

The set of main factors affecting the reliability of distribution network power supply described in this step includes: external factors and internal factors, which are set as set A.

S2, according to the AHP method, the factor set is layered, each layer has several evaluation indicators, and the evaluation index system of factors affecting the reliability of the distribution network is established;

In this step, the content includes: stratifying the factor set A, that is, A={A ₁ , A ₂ }={external factor, internal factor}, the external factor A ₁ ={A ₁₁ , A ₁₂ }={natural environment, external force damage}; the internal factors A ₂ ={A ₂₁ , A ₂₂ , A ₂₃ , A ₂₄ }={grid structure, equipment level, power distribution automation level, management level}, divided Each sub-factor after the layer represents several evaluation indicators of this layer.

S3. Construct the judgment matrix of the evaluation indicators of the lower layer relative to the evaluation indicators of the upper layer, complete the single-level sorting, total hierarchical sorting and consistency verification, and obtain the weight of each indicator in the evaluation indicators of each layer;

In this step, the content described includes:

(1) Starting from the criterion layer, construct the judgment matrix of the evaluation indicators of the lower layer relative to the evaluation indicators of the upper layer. The judgment matrix can be defined as:

(1)

In the formula Represents the judgment value obtained by comparing the i element and the j element in the evaluation index of this layer, is the number of evaluation indicators in this layer, that is, the judgment matrix of order.

(2) For each judgment matrix Calculate the largest eigenvalue and its corresponding eigenvector. This eigenvector is the single ranking of the importance of each evaluation factor, that is, the weight vector. After normalization, it is recorded as ,Right now , . in is the number of evaluation indicators in this layer, is the weight vector of the criterion layer relative to the target layer, is the weight vector of the scheme layer relative to the criterion layer.

(3) Do a consistency check on each judgment matrix, the formula can be recorded as:

(2)

in, is the maximum eigenvalue of the judgment matrix, n is the dimension of the judgment matrix; CI and RI are the consistency index and the average random consistency index respectively, and RI is a known constant. If CR<0.1, it is considered that the consistency of the judgment matrix is acceptable. If CR<0.1 is not satisfied, the values of the elements of the judgment matrix need to be adjusted until the consistency is satisfactory.

(4) According to the calculation result of the single ranking weight vector, calculate the weight vector of the total ranking of the plan layer relative to the target layer, count it as vector B, and use the total ranking consistency ratio CR for verification.

(3)

(4)

in, is the weight value of the nth factor in the criterion layer, , They are the consistency index and the average random consistency index of the single-ranking of the scheme layer to the criterion layer, respectively. When CR<0.1, the result of the total ranking of the hierarchy is considered satisfactory.

S3, using the fuzzy comprehensive evaluation method to conduct an overall evaluation of the factors affecting the reliability of power supply in the distribution network, and then determine the degree of correlation between the reliability of power supply and each influencing factor;

In this step, the content described includes:

1) Create a factor set , is a sub-factor set of factor set A, sub-factor set There are several evaluation indicators, namely , get the subfactor set according to the S3 step Influence weight on A ,index pair of factor sets The influence weight of .

2) For each evaluation index Divided into m comment levels, namely , each level can correspond to a fuzzy subset, and the specific level can be described with appropriate language according to the evaluation content.

3) After constructing the hierarchical fuzzy subset, each indicator in the factor set should be one by one To quantify, that is, to determine the degree of membership of the evaluated thing to each level of fuzzy subsets from a single indicator , and then get the fuzzy relationship matrix R.

(5)

in, Indicates from the factor check it out Degree of membership of a class fuzzy subset.

4) In the fuzzy comprehensive evaluation, the weight vector of the evaluation factors is determined according to the above-mentioned AHP: .

5) Use a suitable operator to convert with each evaluated thing Synthesize to get the fuzzy comprehensive evaluation result vector of each evaluated thing . which is:

(6)

in By and First It is obtained by column operation, which means that the evaluated thing is right as a whole The degree of membership of the hierarchical fuzzy subset.

Determining the evaluation level of the influencing factors of power supply reliability , that is, the final score of the influencing factors of power supply reliability is given, and then the evaluation result is determined.

The embodiments of the present invention described above are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims (3)

1. a distribution network reliability influencing factor analysis method based on fuzzy comprehensive method, is characterized in that, comprises the following steps: Determine the main factor set that affects the power supply reliability of the distribution network, and stratify the factor set according to the analytic hierarchy process. The judgment matrix of the upper-level evaluation index completes single-level sorting, total-level sorting and consistency verification, obtains the weight of each index in each level of evaluation indicators, and uses the fuzzy synthesis method to conduct an overall evaluation of the factors affecting the reliability of distribution network power supply. Then determine the degree of correlation between power supply reliability and various influencing factors, and provide guidance for distribution network planning. 2. a kind of distribution network reliability influence factor analysis method based on fuzzy comprehensive method as claimed in claim 1, is characterized in that, determines the main factor set that influences distribution network power supply reliability to comprise: external factor and internal factor, Let it be set A. 3. a kind of distribution network reliability influencing factor analysis method based on fuzzy synthesis method as claimed in claim 1, is characterized in that, according to AHP, this factor set is stratified, and every layer has several evaluation indexes, The steps of establishing the evaluation index system of distribution network reliability influencing factors include: layering the factor set A, that is, A={A ₁ , A ₂ }={external factors, internal factors}, the external factors A ₁ ={ A ₁₁ , A ₁₂ }={natural environment, external force damage}; the internal factors A ₂ ={A ₂₁ , A ₂₂ , A ₂₃ , A ₂₄ }={grid structure, equipment level, power distribution automation level, Management level}, each sub-factor after stratification represents several evaluation indicators of this stratum.