CN115345524B - A method and device for constructing a distribution transformer energy efficiency evaluation system - Google Patents

Abstract

The invention discloses a method and a device for constructing an energy efficiency evaluation system of a distribution transformer, which are used for acquiring evaluation indexes of multiple energy efficiency evaluations based on energy consumption analysis of the distribution transformer; classifying all the evaluation indexes into qualitative indexes and quantitative indexes, quantitatively preprocessing the qualitative indexes, and giving a weight initial value to each evaluation index; determining relative coefficients among the evaluation indexes, and adjusting the weight initial value of each evaluation index to obtain the weight value of each evaluation index; and (5) associating the evaluation indexes and the corresponding weight values, and constructing and obtaining a distribution transformer energy efficiency evaluation system. According to the invention, through analyzing the relevance of the energy consumption, the basic attribute parameters such as the distribution transformer material, design and the like and the operation parameters, the evaluation index and the corresponding weight affecting the energy efficiency of the distribution transformer are determined fundamentally, so that an accurate energy efficiency evaluation system is constructed, and the power grid optimizing operation and the distribution transformer industry optimizing upgrading are assisted.

Description

A method and device for constructing a distribution transformer energy efficiency evaluation system

technical field

The invention relates to the technical field of smart grids, in particular to a method and device for constructing an energy efficiency evaluation system of distribution transformers.

Background technique

According to statistics, the loss of distribution transformers as the core equipment of the power grid accounts for 40-50% of the power loss in transmission and distribution, and the market demand for high-efficiency transformers is constantly increasing. The power industry is also continuously introducing national standards such as "Energy Efficiency Limits and Energy Efficiency Levels of Power Transformers" to regulate and reduce the no-load and load losses of the currently used distribution transformers.

While actively improving and guiding energy-saving distribution transformers into the network, it is necessary to evaluate and analyze the energy efficiency indicators of distribution transformers, trying to find out the impact of relevant parameters on the energy efficiency of distribution transformers, and provide reference for the subsequent industrial upgrading of distribution transformers. At home and abroad, representative typical systems or equipment have been analyzed, an analysis model has been established, and relevant schemes for improving the energy efficiency of the system or equipment have been given through the simulation of the model software.

For example, the patent CN107122881A discloses a comprehensive energy efficiency evaluation system based on the distribution station area. The system includes: a comprehensive energy efficiency index module, including a plurality of index units and an adder; The permutation pattern is used to make multiple sequential logical judgments, and each logical judgment is counted and added to obtain the score of each index unit; the index weight calculation module is used to obtain the weight value of each index unit; the comprehensive energy efficiency evaluation module , which is used to calculate the comprehensive energy efficiency of the distribution station area according to the score of each index unit and its corresponding weight value. This scheme can realize the parallel collection of various data of the distribution station area, and perform real-time processing, and realize the comprehensive evaluation of the comprehensive energy efficiency of the distribution station area, and the evaluation steps are simple, the cost is low, and the results are intuitive and reliable.

For example, the patent CN114943463A provides an evaluation method for energy-saving technical measures of distribution network, constructing an evaluation index system including target layer, criterion layer and index layer, from the perspective of grid structure, grid energy efficiency, grid economy and grid environmental benefits4 A three-level index evaluation system is constructed from each dimension, and combined with the actual situation of energy-saving measures in the power grid, the impact of different energy-saving technical measures on energy-saving benefits in different dimensions is obtained.

Although the evaluation scheme given by the above scheme has solved the problems of cumbersome processes and steps in the previous technology, the evaluation system constructed is still not perfect, and the degree of refinement and accuracy is still insufficient. Moreover, the above scheme is aimed at evaluating the energy efficiency of the distribution network area, and does not apply to the energy efficiency evaluation of distribution transformers.

Therefore, how to build an energy efficiency evaluation system for distribution transformers to achieve accurate evaluation of energy efficiency for distribution transformers and help optimize and upgrade the distribution transformer industry is an urgent problem to be solved by those skilled in the art.

Contents of the invention

Aiming at the defects in the above-mentioned prior art, the present invention provides a method and device for constructing a distribution transformer energy efficiency evaluation system. By analyzing the relationship between energy consumption and distribution transformer materials and design and other basic attribute parameters and operating parameters, from Determine the evaluation index of energy efficiency at the root, and calculate the weight value of each energy efficiency evaluation index, associate the evaluation index with the corresponding weight value, and construct an accurate energy efficiency evaluation system. By considering the determination of the relative relationship between distribution transformer energy efficiency traceability and evaluation indicators, the energy efficiency evaluation system constructed can help the industry optimization and upgrading of distribution transformers, and can provide support for the optimization methods of distribution transformers' main materials, process basis and operation control .

In the first aspect, the present invention provides a method for constructing a distribution transformer energy efficiency evaluation system, comprising the following steps:

Based on the energy consumption analysis of distribution transformers, multiple evaluation indicators for energy efficiency evaluation are obtained;

Divide all evaluation indicators into categories, divide them into qualitative indicators and quantitative indicators, perform quantitative preprocessing on qualitative indicators, and give each evaluation indicator a weight initial value;

Determine the relative coefficient between each evaluation index, adjust the weight initial value of each evaluation index, and obtain the weight value of each evaluation index;

Correlating the evaluation indicators and corresponding weight values, the energy efficiency evaluation system of distribution transformers is constructed.

Further, based on the energy consumption analysis of distribution transformers, multiple evaluation indicators for energy efficiency evaluation are obtained, including:

Obtain the relationship between the power loss of the distribution transformer and the influencing parameters, specifically expressed as:

Among them, W is the power loss of the distribution transformer, L ₁ is the no-load loss of the distribution transformer, L ₂ is the short-circuit loss of the distribution transformer, I ₁ % is the percentage of the no-load current of the distribution transformer, and u ₂ % is the rated short-circuit of the distribution transformer Impedance voltage percentage, K _Q is the economic equivalent of reactive power, E is the total electricity delivered by the distribution transformer in a year, is the annual average power coefficient of the distribution transformer, Se _is the rated capacity of the distribution transformer, t _max is the annual maximum load loss time of the distribution transformer, and t is the annual operation time of the distribution transformer;

The basic property parameters and operating parameters of the distribution transformer related to the influencing parameters are given;

Decompose the basic attribute parameters and operating parameters of distribution transformers to obtain multiple evaluation indicators for energy efficiency evaluation.

Further, perform quantitative preprocessing on qualitative indicators, including:

Perform value assignment processing for each qualitative index, and obtain the first value of each qualitative index;

Based on the first numerical value of the qualitative index and the type of the qualitative index, mean value processing is performed on the first numerical value to obtain the preprocessed data of the qualitative index;

Among them, the assignment process is carried out for each qualitative index, which specifically includes: collecting the text comments of each qualitative index, and giving the assignment vector, combining the text comments and the assignment vector to obtain the first value of each qualitative index, and the second A value expressed as , where D _i is the first numerical value of the i-th qualitative index, text _i is the text comment of the i-th qualitative index, and j is the number of text comments of the i-th qualitative index.

Further, based on the first numerical value of the qualitative index and the type of the qualitative index, mean value processing is performed on the first numerical value, specifically including:

According to the change trend of the impact on energy efficiency, determine the types of qualitative indicators, which are respectively defined as the first type and the second type, where the first type is positively correlated with energy efficiency impact, and the second type is negatively correlated with energy efficiency impact;

The formula for processing the first numerical value of the first type is: ;

The formula for processing the first numerical value of the second type is: ;

in, is the first value of the i-th qualitative index after mean value processing, is the limit maximum value in the first numerical value of the i-th qualitative index, is the extreme minimum value in the first numerical value of the i-th qualitative index, is the benchmark value of the first numerical value of the i-th qualitative indicator.

Further, assign initial weights to each evaluation index, including:

Calculate the entropy value corresponding to each evaluation index based on the characteristic proportion of each evaluation index in all evaluation indexes;

According to the entropy value of each evaluation index, the corresponding difference coefficient is obtained;

Through the difference coefficient, calculate the weight initial value of each evaluation indicator.

Further, according to the entropy value of each evaluation index, the corresponding difference coefficient is obtained, and the calculation formula is as follows:

in, is the difference coefficient of the i-th evaluation index, is the value of the i-th evaluation index after quantitative preprocessing;

Through the difference coefficient, the initial weight value of each evaluation indicator is calculated, and the calculation formula is as follows:

in, is the initial weight value of the i-th evaluation index.

Further, determine the relative coefficients between each evaluation index, adjust the initial weight value of each evaluation index, and obtain the weight value of each evaluation index, specifically including:

Sort all evaluation indicators according to their importance to obtain the evaluation index sequence;

Based on the weight ratio of adjacent evaluation indicators in the evaluation index sequence, the relative weight value of each evaluation index is obtained;

According to the weight initial value and weight relative value of the evaluation index, combined with the proportional coefficient, the weight value of each evaluation index is given.

Further, based on the weight ratio of adjacent evaluation indicators in the evaluation index sequence, the relative weight value of each evaluation index is obtained. The specific formula is:

in, is the relative weight value of the i-th evaluation indicator, k is the number of evaluation indicators, is the value of the i-th evaluation index after quantitative preprocessing;

According to the initial weight value and relative weight value of the evaluation index, combined with the proportional coefficient, the weight value of each evaluation index is given. The calculation formula is as follows:

in, is the weight value of the i-th evaluation index, is the proportional coefficient of the i-th evaluation index, is the initial weight value of the i-th evaluation index.

Further, the associated evaluation indicators and corresponding weight values are constructed to obtain the distribution transformer energy efficiency evaluation system, which specifically includes:

Determine the evaluation index matrix of the distribution transformer, expressed as: , where p _i is the i-th evaluation index, and k is the number of evaluation indexes;

Obtain the weight matrix including the weight value of each evaluation index, and the weight matrix is expressed as: , in, is the weight value of the i-th evaluation indicator, k is the number of evaluation indicators;

The evaluation index matrix and weight matrix are combined to construct the distribution transformer energy efficiency evaluation system.

In the second aspect, the present invention also provides a device for constructing a distribution transformer energy efficiency evaluation system, adopting the above method for constructing a distribution transformer energy efficiency evaluation system, including:

The energy consumption analysis module is used to analyze the energy consumption of distribution transformers, obtain multiple evaluation indicators for energy efficiency evaluation, and classify all evaluation indicators into qualitative indicators and quantitative indicators;

The data processing module is used for quantitative preprocessing of the qualitative indicators, and assigns initial weights to each evaluation index, determines the relative coefficients between each evaluation index, adjusts the initial weight value of each evaluation index, and obtains The weight value of each evaluation index;

The evaluation system construction module is used to correlate evaluation indicators and corresponding weight values to construct an energy efficiency evaluation system for distribution transformers.

A method and device for constructing a distribution transformer energy efficiency evaluation system provided by the present invention at least include the following beneficial effects:

(1) By analyzing the relationship between energy consumption and distribution transformer materials and design and other basic attribute parameters and operating parameters, the evaluation index of distribution transformer energy efficiency can be determined from the root. Improve the accuracy of distribution transformer energy efficiency evaluation, and also provide support for the optimization of the main materials, process basis and operation control of subsequent distribution transformers, and give a scientific basis.

(2) Assigning and averaging the qualitative indicators can effectively ensure the objectivity and rationality of the subsequent index evaluation system.

(3) The weight of each evaluation index is determined by processing the initial value of the weight, the relative coefficient, and the relative value of the weight, which not only considers the integrity of the index evaluation system, but also considers the interaction between each evaluation index. A more accurate and objective comprehensive evaluation of the energy efficiency of distribution transformers improves the scientificity of distribution transformer network decision-making.

Description of drawings

Fig. 1 is a schematic flow chart of a method for constructing a distribution transformer energy efficiency evaluation system provided by the present invention;

Fig. 2 is a schematic flow chart of the preprocessing for quantitatively quantifying qualitative indicators according to an embodiment of the present invention;

Fig. 3 is a schematic flow chart of assigning the initial value of the weight of each evaluation index according to a certain embodiment provided by the present invention;

Fig. 4 is a schematic diagram of a device for constructing a distribution transformer energy efficiency evaluation system provided by the present invention.

Detailed ways

In order to better understand the above-mentioned technical solution, the above-mentioned technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates otherwise, "multiple" Generally contain at least two.

It should also be noted that the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that an article or arrangement comprising a list of elements includes not only those elements but also includes items not expressly listed. other elements of the product, or elements inherent in the product or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in an article or device comprising said element.

In order to complete the upgrading and transformation of high-energy-consuming distribution transformers, it is necessary to evaluate the equipment quality of new energy-saving distribution transformers in advance, form intelligent result information, and feedback the optimal design methods to help optimize the operation of the power grid and the transformer industry optimization upgrade.

The energy efficiency of distribution transformers refers to the efficiency of transmission, conversion and utilization of electric energy in distribution transformers. It is an important economic, technical and benefit factor considered by power grid operation. To evaluate the energy efficiency of distribution transformers, a reasonable, accurate and effective energy efficiency evaluation index system must first be established.

As shown in Figure 1, the present invention provides a method for constructing a distribution transformer energy efficiency evaluation system, including the following steps:

Based on the energy consumption analysis of distribution transformers, multiple evaluation indicators for energy efficiency evaluation are obtained;

Divide all evaluation indicators into categories, divide them into qualitative indicators and quantitative indicators, perform quantitative preprocessing on qualitative indicators, and give each evaluation indicator a weight initial value;

Determine the relative coefficient between each evaluation index, adjust the weight initial value of each evaluation index, and obtain the weight value of each evaluation index;

Correlating the evaluation indicators and corresponding weight values, the energy efficiency evaluation system of distribution transformers is constructed.

Through the energy consumption analysis of distribution transformers, the evaluation index of energy efficiency evaluation is obtained from the source, so that the energy efficiency evaluation system of distribution transformers can be constructed more accurately and clearly, which can provide the optimization method for the main materials, process basis and operation control of distribution transformers Provide support.

Among them, based on the energy consumption analysis of distribution transformers, multiple evaluation indicators for energy efficiency evaluation are obtained, including:

Obtain the relationship between the power loss of the distribution transformer and the influencing parameters, specifically expressed as:

Among them, W is the power loss of the distribution transformer, L ₁ is the no-load loss of the distribution transformer, L ₂ is the short-circuit loss of the distribution transformer, I ₁ % is the percentage of the no-load current of the distribution transformer, and u ₂ % is the rated short-circuit of the distribution transformer Impedance voltage percentage, K _Q is the economic equivalent of reactive power, E is the total electricity delivered by the distribution transformer in a year, is the annual average power coefficient of the distribution transformer, Se _is the rated capacity of the distribution transformer, t _max is the annual maximum load loss time of the distribution transformer, and t is the annual operation time of the distribution transformer;

The basic property parameters and operating parameters of the distribution transformer related to the influencing parameters are given;

Decompose the basic attribute parameters and operating parameters of distribution transformers to obtain multiple evaluation indicators for energy efficiency evaluation.

Distribution transformers are mainly divided into three-dimensional wound core transformers and traditional laminated core transformers. The current power system industry mainly uses traditional laminated iron core transformers. However, the three-dimensional wound iron core transformer is different from the planar iron core structure. The structure has been modified, the no-load loss is small, and the structural strength and short-circuit resistance have been improved. , which is more in line with the high energy efficiency in theory, and is also the development trend of the power industry. However, the optimization iteration of the industry needs to consider the loss of distribution transformers from various aspects, which can be summarized into two categories: basic attribute parameters of distribution transformers and operating parameters of distribution transformers.

The basic attribute parameters of the distribution transformer include the factory energy efficiency of the distribution transformer, the no-load loss of the distribution transformer, the load loss of the distribution transformer, and the no-load current of the distribution transformer. Among them, the factory energy efficiency of the distribution transformer also includes the material and material proportion of the distribution transformer. The optional material is amorphous alloy, S11, etc. The no-load loss of the distribution transformer is a fixed loss, which involves the core type, core material, etc. Distribution transformer load loss is a variable loss, mainly copper loss, related to the material of the cable. The no-load current of the distribution transformer also involves the iron core, including the iron core structure and the power conversion method related to the iron core.

The operating parameters of the distribution transformer include the power factor of the distribution transformer, the unbalance rate of the three phases, the load factor and so on.

Of course, the above are only limited enumerations of the basic attribute parameters and operating parameters of distribution transformers, and are not exhaustive. The specific types and quantities of the basic attribute parameters and operating parameters of distribution transformers involved in the evaluation of each application scenario or different types of distribution transformers will be different, and no specific restrictions are made here.

As shown in Figure 2, the quantitative preprocessing of the qualitative indicators includes:

Perform value assignment processing for each qualitative index, and obtain the first value of each qualitative index;

Based on the first numerical value of the qualitative index and the type of the qualitative index, mean value processing is performed on the first numerical value to obtain the preprocessed data of the qualitative index;

Among them, the assignment process is carried out for each qualitative index, which specifically includes: collecting the text comments of each qualitative index, and giving the assignment vector, combining the text comments and the assignment vector to obtain the first value of each qualitative index, and the second A value expressed as , where D _i is the first numerical value of the i-th qualitative index, text _i is the text comment of the i-th qualitative index, and j is the number of text comments of the i-th qualitative index.

Among them, based on the first value of the qualitative index and the type of the qualitative index, the first value is averaged, specifically including:

According to the change trend of the impact on energy efficiency, determine the types of qualitative indicators, which are respectively defined as the first type and the second type, where the first type is positively correlated with energy efficiency impact, and the second type is negatively correlated with energy efficiency impact;

The formula for processing the first numerical value of the first type is: ;

The formula for processing the first numerical value of the second type is: ;

in, is the first value of the i-th qualitative index after mean value processing, is the limit maximum value in the first numerical value of the i-th qualitative index, is the extreme minimum value in the first numerical value of the i-th qualitative index, is the benchmark value of the first numerical value of the i-th qualitative indicator.

The types of qualitative indicators can be roughly divided into two categories. The first type is positively related to the impact of energy efficiency, that is to say, the larger the first value of the first type of qualitative indicators, the more beneficial it is; on the contrary, the second type is related to the impact of energy efficiency. Negative correlation, that is to say, the smaller the first numerical value of the second type of qualitative index, the more beneficial it is.

As shown in Figure 3, among them, the initial value of the weight of each evaluation index is given, specifically including:

Calculate the entropy value corresponding to each evaluation index based on the characteristic proportion of each evaluation index in all evaluation indexes;

According to the entropy value of each evaluation index, the corresponding difference coefficient is obtained;

Through the difference coefficient, calculate the weight initial value of each evaluation indicator.

Further, according to the entropy value of each evaluation index, the corresponding difference coefficient is obtained, and the calculation formula is as follows:

in, is the difference coefficient of the i-th evaluation index, is the value of the i-th evaluation index after quantitative preprocessing, Represents the characteristic proportion of the i-th evaluation index in all evaluation indexes, Represents the entropy value corresponding to the i-th evaluation index.

Through the difference coefficient, the initial weight value of each evaluation indicator is calculated, and the calculation formula is as follows:

in, is the initial weight value of the i-th evaluation index.

Further, determine the relative coefficients between each evaluation index, adjust the initial weight value of each evaluation index, and obtain the weight value of each evaluation index, specifically including:

Sort all evaluation indicators according to their importance to obtain the evaluation index sequence;

Based on the weight ratio of adjacent evaluation indicators in the evaluation index sequence, the relative weight value of each evaluation index is obtained;

According to the weight initial value and weight relative value of the evaluation index, combined with the proportional coefficient, the weight value of each evaluation index is given.

Further, based on the weight ratio of adjacent evaluation indicators in the evaluation index sequence, the relative weight value of each evaluation index is obtained. The specific formula is:

in, is the relative weight value of the i-th evaluation indicator, k is the number of evaluation indicators, is the value of the i-th evaluation index after quantitative preprocessing;

According to the initial weight value and relative weight value of the evaluation index, combined with the proportional coefficient, the weight value of each evaluation index is given. The calculation formula is as follows:

in, is the weight value of the i-th evaluation index, is the proportional coefficient of the i-th evaluation index, is the initial weight value of the i-th evaluation index.

The weight of the evaluation index not only considers the initial value of the weight (the objective situation of the first value of the evaluation index), but also needs to consider the relative value of the weight (the relative relationship between the evaluation indexes), and thus set the corresponding proportional coefficient, so as to give The final weight value is more accurate. Of course, the proportionality coefficient can be adjusted according to different application scenarios or different types of distribution transformers, and the specifically determined value is not limited here.

By processing the initial value of the weight, the relative coefficient and the relative value of the weight, etc., the weight of each evaluation index is determined, which not only considers the integrity of the index evaluation system, but also considers the interaction between each evaluation index, which can be more accurate and accurate. Objectively realize the comprehensive evaluation of the energy efficiency of distribution transformers.

Further, the associated evaluation indicators and corresponding weight values are constructed to obtain the distribution transformer energy efficiency evaluation system, which specifically includes:

Determine the evaluation index matrix of the distribution transformer, expressed as: , where p _i is the i-th evaluation index, and k is the number of evaluation indexes;

Obtain the weight matrix including the weight value of each evaluation index, and the weight matrix is expressed as: , in, is the weight value of the i-th evaluation indicator, k is the number of evaluation indicators;

The evaluation index matrix and weight matrix are combined to construct the distribution transformer energy efficiency evaluation system.

The weight value corresponding to each evaluation index is different. Through the collection of evaluation index matrix and weight matrix, the energy efficiency evaluation system of distribution transformers is built.

The method for constructing the distribution transformer energy efficiency evaluation system given in the above examples can determine the evaluation index of distribution transformer energy efficiency from the source by analyzing the relationship between energy consumption, distribution transformer materials and design and other basic attribute parameters and operating parameters. Improve the accuracy of energy efficiency evaluation, and also provide support for the optimization of the main materials, process basis and operation control of subsequent distribution transformers.

As shown in Figure 4, the present invention also provides a device for constructing a distribution transformer energy efficiency evaluation system, adopting the above method for constructing a distribution transformer energy efficiency evaluation system, including:

The energy consumption analysis module is used to analyze the energy consumption of distribution transformers, obtain multiple evaluation indicators for energy efficiency evaluation, and classify all evaluation indicators into qualitative indicators and quantitative indicators;

The data processing module is used for quantitative preprocessing of the qualitative indicators, and assigns initial weights to each evaluation index, determines the relative coefficients between each evaluation index, adjusts the initial weight value of each evaluation index, and obtains The weight value of each evaluation index;

The evaluation system construction module is used to correlate evaluation indicators and corresponding weight values to construct an energy efficiency evaluation system for distribution transformers.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (2)

1. The method for constructing the energy efficiency evaluation system of the distribution transformer is characterized by comprising the following steps of:

the relation between the power loss of the distribution transformer and the influence parameters is obtained, and the relation is specifically expressed as follows:

；

wherein W is the power loss of the distribution transformer, L ₁ For no-load loss of distribution transformer, L ₂ For short-circuit loss of distribution transformer, I ₁ % is the percentage of the no-load current of the distribution transformer, u ₂ % is the rated short-circuit impedance of the distribution transformerPercentage of voltage, K _Q E is the annual total power transmission quantity of the distribution transformer for reactive economic equivalent,is the annual average power coefficient of the distribution transformer, S _e For rated capacity of distribution transformer, t _max The annual maximum load loss time of the distribution transformer is t, and the annual input operation time of the distribution transformer is t;

providing basic attribute parameters and operation parameters of the distribution transformer related to the influence parameters, wherein the basic attribute parameters of the distribution transformer comprise the delivery energy efficiency of the distribution transformer, the no-load loss of the distribution transformer, the load loss of the distribution transformer and the no-load current of the distribution transformer, and the operation parameters of the distribution transformer comprise the power factor, the unbalance rate of three phases and the load factor of the distribution transformer;

decomposing basic attribute parameters and operation parameters of the distribution transformer to obtain evaluation indexes of multiple energy efficiency evaluations;

classifying all the evaluation indexes into qualitative indexes and quantitative indexes, quantitatively preprocessing the qualitative indexes, and giving a weight initial value to each evaluation index;

sequencing all the evaluation indexes according to the importance degree to obtain an evaluation index sequence;

based on the weight ratio of adjacent evaluation indexes in the evaluation index sequence, the weight relative value of each evaluation index is obtained, and the specific formula is as follows:

；

wherein ,the weight relative value of the ith evaluation index, k is the number of the evaluation indexes, and +.>The value of the ith evaluation index after quantitative pretreatment;

according to the initial weight value and the relative weight value of the evaluation index, the weight value of each evaluation index is given by combining the proportional coefficient, and the calculation formula is as follows:

；

wherein ,weight value for the ith evaluation index, +.>Scale factor for the ith evaluation index, +.>The weight initial value of the ith evaluation index;

determining an evaluation index matrix of the distribution transformer, wherein the evaluation index matrix is expressed as:, wherein ,p_i The i-th evaluation index is the number of the evaluation indexes, and k is the number of the evaluation indexes;

acquiring a weight matrix comprising weight values of each evaluation index, wherein the weight matrix is expressed as:, wherein ,/>The weight value of the ith evaluation index is k, and the number of the evaluation indexes is k;

the evaluation index matrix and the weight matrix are collected, and a distribution transformer energy efficiency evaluation system is constructed;

the pretreatment for quantifying qualitative indexes specifically comprises the following steps:

performing assignment processing on each qualitative indicator to obtain a first numerical value of each qualitative indicator;

based on the first numerical value of the qualitative index and the type of the qualitative index, carrying out averaging treatment on the first numerical value to obtain data after qualitative index pretreatment;

wherein, carry out the assignment processing to each qualitative index, specifically include: collecting the text comments of each qualitative index, giving a value vector, combining the text comments and the value vector to obtain a first numerical value of each qualitative index, wherein the first numerical value is expressed as, wherein ,D_i Text, which is the first value of the ith qualitative rating _i The j is the number of the character comments of the qualitative index;

based on the first value of the qualitative index and the type of the qualitative index, carrying out the averaging treatment on the first value, wherein the method specifically comprises the following steps:

determining the type of the qualitative index according to the change trend of the influence on the energy efficiency, and defining the type as a first type and a second type respectively, wherein the first type is positively correlated with the influence on the energy efficiency, and the second type is negatively correlated with the influence on the energy efficiency;

the first numerical processing formula for the first type is:；

the first numerical processing formula for the second type is:；

wherein ,for the first value of the ith qualitative rating after the averaging, the ++>For the limit maximum value in the first value of the ith qualitative rating, < >>For the limit minimum in the first value of the ith qualitative rating,/min->A reference value for the i-th qualitative indicator first value;

giving each evaluation index a weight initial value, specifically comprising:

calculating the entropy value corresponding to each evaluation index based on the characteristic proportion of each evaluation index in all the evaluation indexes;

obtaining a corresponding difference coefficient according to the entropy value of each evaluation index;

calculating a weight initial value of each evaluation index through the difference coefficient;

according to the entropy value of each evaluation index, a corresponding difference coefficient is obtained, and the calculation formula is as follows:

；

wherein ,for the difference coefficient of the ith evaluation index, < +.>The value of the ith evaluation index after quantitative pretreatment;

the weight initial value of each evaluation index is calculated through the difference coefficient, and the calculation formula is as follows:

；

wherein ,the weight initial value of the i-th evaluation index.

2. An apparatus for constructing a power distribution transformer energy efficiency rating system, using the method for constructing a power distribution transformer energy efficiency rating system as defined in claim 1, comprising:

the energy consumption analysis module is used for carrying out energy consumption analysis on the distribution transformer, obtaining a plurality of evaluation indexes of energy efficiency evaluation, classifying all the evaluation indexes into qualitative indexes and quantitative indexes;

the data processing module is used for quantitatively preprocessing the qualitative indexes, endowing each evaluation index with a weight initial value, determining the relative coefficient among the evaluation indexes, and adjusting the weight initial value of each evaluation index to obtain the weight value of each evaluation index;

and the evaluation system construction module is used for associating the evaluation indexes and the corresponding weight values and constructing and obtaining the energy efficiency evaluation system of the distribution transformer.