CN106780108A - A kind of distribution transformer state evaluating method based on improvement evidential reasoning fusion - Google Patents

Abstract

The present invention relates to electrical equipment technical field, and in particular to a kind of based on the distribution transformer state evaluating method for improving evidential reasoning fusion, including：Step 1, according to distribution transformer Test Information to be assessed, patrol and examine information, the data of operation information, set up distribution transformer state estimation two-level index system；Step 2, distribution transformer second level index evidence to be assessed is obtained using THE FUZZY EVALUATING METHOD on Comment gathersInitial basic probability assignment；Step 3, the weight of each layer index relative importance is determined using improved H, and its confidence level coefficient is calculated using formula；Step 4, by confidence level coefficient to initial evidence source change obtain basic probability assignment；Step 5, evidence fusion is carried out using improved evidential reasoning composition rule, so as to obtain the end-state of distribution transformer.The appraisal procedure sets up the layered multi-stage state estimation model of distribution transformer by analyzing distribution transformer state information.

Description

A kind of distribution transformer state evaluating method based on improvement evidential reasoning fusion

Technical field

The invention belongs to electrical equipment technical field, more particularly to a kind of distribution transformer based on improvement evidential reasoning fusion Device state evaluating method.

Background technology

Distribution transformer as distribution system nucleus equipment, its operation conditions directly affects whole electricity consumption side user's Electrical Safety and stabilization.Distribution transformer health status is estimated, power operation personnel can be helped to need to understand in time The health status of distribution transformer, to be overhauled to it and to be safeguarded.Therefore correctly commented for the state of distribution transformer Estimate with important Research Significance.

Distribution transformer includes multiple parts, and each part has different status informations, therefore scientific and effective information Treatment model is the core to distribution transformer state estimation.And influence the information content of distribution transformer end-state numerous, this A little information are in terms of different and different levels has reacted the state of transformer, have related uncertain and ambiguity. Directly will be unable to accurately be assessed using these quantity of states.

The hair of application number 201310136283.8 entitled " the network distribution transformer state evaluating method based on fuzzy theory " Bright patent, although improve operating efficiency and state estimation accuracy rate, the state for being capable of and each part overall to transformer is entered Row assessment, final appraisal results are given in the form of possibility degree, overcome Traditional measurements result to determine that it is unilateral that state is provided Property.But, most crucial information fusion part grey correlation in appraisal procedure, it is impossible to solve influence distribution transformer numerous The uncertainty and conflicting associated between state information.

The content of the invention

The invention aims to pass through to analyze distribution transformer state information, the layering for setting up multiple attribute decision making (MADM) is commented Estimate system, on the basis of fuzzy comprehensive evoluation and analytic hierarchy process (AHP), evidential reasoning fusion is improved, set up distribution transformer The layered multi-stage state estimation model of device.Selected in numerous distribution transformer information and processed so as to provide one kind just True distribution transformer state evaluating method.

To achieve the above object, the technical solution adopted by the present invention is：A kind of distribution based on improvement evidential reasoning fusion Transformer condition evaluation, comprises the following steps：

Step 1, according to distribution transformer Test Information to be assessed, patrol and examine information, the data of operation information, set up distribution Transformer State Assessment two-level index system；

Step 2, distribution transformer second level index evidence to be assessed is obtained using THE FUZZY EVALUATING METHOD on Comment gathers V's Initial basic probability assignment；

Step 3, the weight that each layer index relative importance is determined using improved H, and calculated using formula Its confidence level coefficient；

Step 4, by confidence level coefficient to initial evidence source change obtain basic probability assignment；

Step 5, evidence fusion is carried out using improved evidential reasoning composition rule, so as to obtain the final of distribution transformer State.

In the above-mentioned distribution transformer state evaluating method based on improvement evidential reasoning fusion, the tool of the step 2 Body method is as follows：

1) the Comment gathers V is divided into good, general, attention, abnormal four kinds of different conditions, V={ v₁,v₂,v₃,v₄} ={ good, general, attention, exception }；

2) degree of membership of the evaluation index for Comment gathers is determined；Comprise the following steps：

A. the evaluation index that can directly quantify is determined using relative inferiority degree；

B. ambiguity, it is impossible to the evaluation index of quantification treatment using formulating detailed bonus point table, the evaluation index according to plus Divide table bonus point, its state is quantified.

In the above-mentioned distribution transformer state evaluating method based on improvement evidential reasoning fusion, confidence described in step 3 Spend coefficient computing formula be：

β_ij=w_ij/w_ik(1)；

β in formula (1)_ijIt is confidence level coefficient, the lower floor single index { x of 1 grade of index i_i1,x_i2,...,x_ij..., x_iJ} Weight be respectively { w_i1,w_i2,...,w_ij,...,w_iJ, w_ikIt is then the maximum of above-mentioned weighted value.

It is basic described in step 4 in the above-mentioned distribution transformer state evaluating method based on improvement evidential reasoning fusion Probability assignments formula is：

m_ij(v_n)=β_ijμ_ij,n(2)；

M in formula (2)_ij(v_n) it is basic probability assignment, β_ijIt is confidence level coefficient, μ_ij,nIt is probability assignment.

In the above-mentioned distribution transformer state evaluating method based on improvement evidential reasoning fusion, improved described in step 5 Evidential reasoning composition rule be：

m_i(j+1)(Θ)=m_ij+1(Θ)·m_i(j)(Θ)+K'·δ_i(v_Θ,m) (4)；

K' is the revised conflict factor, δ in formula (3), (4)_i(v_Θ, m) it is conflict allocation proportion, m_i(j+1)(Θ) is Uncertain set probability assignments.

The beneficial effects of the invention are as follows：Using improved evidential reasoning fusion method, influence distribution transformer is solved many The uncertainty and conflicting associated between multimode amount information, not only allow people that reliability is assigned the single unit for assuming space Element, and its subset can also be assigned, this evidence-gathering process much like the mankind on abstraction hierarchies at different levels, it is to avoid certain state Amount deviation is so as to cause the huge deviation of result.On the basis of fuzzy comprehensive evoluation and analytic hierarchy process (AHP), evidential reasoning is merged It is improved, sets up the layered multi-stage state estimation model of distribution transformer, is capable of and each part overall to distribution transformer State is estimated, and overcomes the one-sidedness of Traditional measurements result, and strong antijamming capability and fast convergence rate.

Brief description of the drawings

Fig. 1 is the flow chart of one embodiment of the invention；

Fig. 2 is one embodiment of the invention distribution transformer State Assessment Index System figure；

Fig. 3 is the membership function figure of one embodiment of the invention evaluation index.

Specific embodiment

Embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

The example of the embodiment is shown in the drawings, wherein same or similar label represents identical or class from start to finish As element or the element with same or like function.Below with reference to Description of Drawings embodiment be it is exemplary, only For explaining the present invention, and it is not construed as limiting the claims.

Following disclosure provides many different embodiments or example is used for realizing different structure of the invention.For letter Change disclosure of the invention, hereinafter the part and setting to specific examples are described.They are only merely illustrative, and purpose is not It is to limit the present invention.Additionally, the present invention can in different examples repeat reference numerals and/or letter.This repetition be for Simplify and clearly purpose, the relation between discussed various embodiments and/or setting itself is not indicated.Additionally, this hair It is bright there is provided various specific techniques and the example of material, but those of ordinary skill in the art can be appreciated that other techniques The use of applicability and/or other materials.In addition, fisrt feature described below second feature it " on " structure can be with Be formed as the embodiment of directly contact including the first and second features, it is also possible to be formed in first and second including other feature Embodiment between feature, such first and second feature may not be directly contact.

, it is necessary to explanation in description of the invention, unless otherwise prescribed and limit, term " connected " " connection " should do extensively Reason and good sense solution, can be joined directly together for example, it may be mechanically connecting or electrical connection, or two connections of element internal, Can also be indirectly connected to by intermediary, for those of ordinary skill in the related art, can managed as the case may be Solve the concrete meaning of above-mentioned term.

The present embodiment is adopted the following technical scheme that：A kind of distribution transformer state estimation based on improvement evidential reasoning fusion Method, comprises the following steps：

Step 1, according to distribution transformer Test Information to be assessed, patrol and examine information, the data of operation information, set up distribution Transformer State Assessment two-level index system；

Step 2, distribution transformer second level index evidence to be assessed is obtained using THE FUZZY EVALUATING METHOD on Comment gathers V's Initial basic probability assignment；

Step 3, the weight that each layer index relative importance is determined using improved H, and calculated using formula Its confidence level coefficient；

Step 4, by confidence level coefficient to initial evidence source change obtain basic probability assignment；

Step 5, evidence fusion is carried out using improved evidential reasoning composition rule, so as to obtain the final of distribution transformer State.

Further, the specific method of the step 2 is as follows：

1) the Comment gathers V is divided into good, general, attention, abnormal four kinds of different conditions, V={ v₁,v₂,v3,v₄} ={ good, general, attention, exception }；

2) degree of membership of the evaluation index for Comment gathers is determined；Comprise the following steps：

A. the evaluation index that can directly quantify is determined using relative inferiority degree；

B. ambiguity, it is impossible to the evaluation index of quantification treatment using formulating detailed bonus point table, the evaluation index according to plus Divide table bonus point, its state is quantified.

Further, the computing formula of confidence level coefficient is described in step 3：

β_ij=w_ij/w_ik(1)；

β in formula (1)_ijIt is confidence level coefficient, the lower floor single index { x of 1 grade of index i_i1,x_i2,...,x_ij..., x_iJ} Weight be respectively { w_i1,w_i2,...,w_ij,...,w_iJ, w_ikIt is then the maximum of above-mentioned weighted value.

Further, basic probability assignment formula is described in step 4：

m_ij(v_n)=β_ijμ_ij,n(2)；

M in formula (2)_ij(v_n) it is basic probability assignment, β_ijIt is confidence level coefficient, μ_ij,nIt is probability assignment.

Further, improved evidential reasoning composition rule is described in step 5：

m_i(j+1)(Θ)=m_ij+1(Θ)·m_i(j)(Θ)+K'·δ_i(v_Θ,m) (4)；

K' is the revised conflict factor, δ in formula (3), (4)_i(v_Θ, m) it is conflict allocation proportion, m_i(j+1)(Θ) is Uncertain set probability assignments.

Embodiment 1

As shown in figure 1, set up a kind of based on the distribution transformer state estimation model for improving evidential reasoning fusion, including with Lower specific steps：

S1. comprehensive, unified with the selection from each part of distribution transformer to be assessed under the principle that level is combined Evaluation index amount, sets up the multilevel evaluation system of distribution transformer state.

Because distribution transformer state estimation is influenceed by many indexes, the selection of level index should follow it is comprehensive, The principle that unification is combined with level, should try one's best the qualitative and quantitative index that selection definition is clear and definite, can obtain.The present embodiment 1 By taking oil immersion-type distribution transformer as an example, the characteristics of overhauled according to oil immersion-type distribution transformer from the winding and sleeve pipe of transformer, point Selection evaluation index amount in the parts such as switch, fuel tank, insulating oil, ground connection, non-ionizing energy loss, mark is connect, distribution transformer is set up State evaluation system, as shown in Figure 2.

S2. distribution transformer second level index evidence to be assessed is obtained using THE FUZZY EVALUATING METHOD first on Comment gathers V Beginning basic probability assignment.

Fortune inspection personnel accurately judge the health status of power transformer for convenience, reasonably take appropriate measures, It is " good ", " general ", " attention ", 4 kinds of states of "abnormal" by the state demarcation of distribution transformer with reference to pertinent literature.I.e.：

V={ v₁,v₂,v₃,v₄}={ is good, general, note, abnormal }

Before comprehensive assessment is carried out, first have to determine degree of membership of each index for Comment gathers.In fuzzy mathematics, Certain fuzzy subset in domain can be mapped on [0,1] by function mu (x), and function mu (x) is membership function, is mapped to [0,1] value on is degree of membership.

In distribution transformer state estimation model, the index that can directly quantify can use the concept of relative inferiority degree To determine, to bigger more excellent type index such as earth resistance：

To smaller more excellent type index such as connector temperature：

In formula (1), (2)：d_iIt is the relative inferiority degree of the distribution transformer evaluation index；y_maxOr y_minIt is the index Limiting value, the determination of its value refers to pertinent literature；y₀It is the initial value of the index；y_iIt is index actual measured value.

For with certain ambiguity, it is impossible to the index of quantification treatment, such as filthy level, distribution transformer fuel tank, divide Connect switch etc..Evaluation index that the present embodiment 1 pair cannot quantify formulates detailed bonus point table, it is assumed that preferable operating condition state is 0 point, object to be assessed quantifies its state according to bonus point table bonus point, is mapped on interval [0,1].

The membership function of evaluation index uses Triangle-Profile function and half trapezoidal profile function, as shown in Figure 3.

The determination of membership function：The relative inferiority degree that will be determined above is substituted into membership function, half trapezoidal and triangle The fuzzy boundary of relative inferiority degree four kinds of states of correspondence that shape is combined is interval.Such that it is able to obtain certain evaluation index for shape State V={ v₁,v₂,v₃,v₄Membership function：

X is the relative inferiority degree of evaluation index, v in formula (3), (4), (5), (6)₁(x)~v₄X () represents assessment respectively Index corresponds to state v₁~v₄Membership function；The lower property index x of first order index i_ijRelative to evaluation grade v_nMould Paste assessed value is μ_ij,n。

S3. the analytic hierarchy process (AHP) of application enhancements calculates the weight of each layer index relative importance, and calculates it using formula Confidence level coefficient.

The present embodiment 1 introduces confidence level coefficient and initial evidence source is modified, and the weight of each index is based on improved layer Fractional analysis determines, it is assumed that the lower floor single index { x of 1 grade of index i_i1,x_i2,...,x_ij..., x_iJWeight be respectively {w_i1,w_i2,...,w_ij,...,w_iJ, make w_ikIt is the maximum of above-mentioned weighted value, then confidence level coefficient is：

β_ij=w_ij/w_ik

S4. initial evidence source is changed by confidence level coefficient and obtains basic probability assignment.

In distribution transformer state estimation system, using fuzzy membership function, can be in the hope of second layer index evidence Initial basic probability assignment, its probability assignment be μ_ij,n, probability distribution is modified by confidence level coefficient can be with Obtain basic probability assignment：

m_ij(v_n)=β_ijμ_ij,n

S5. evidence fusion is carried out using improved evidential reasoning composition rule, so as to obtain the final shape of distribution transformer State.

For revised evidence source, evidences conflict implements distribution according to the confidence level of evidence, for two elementary probabilities The synthesis of distribution has following rule：

m_i(2)(v_n)=m_i1(v_n)·m_i2(v_n)+

m_i1(v_n)·m_i2(Θ)+m_i1(Θ)·m_i2(v_n)

+K'·δ_i(v_n,m)

m_i(2)(Θ)=m_i2(Θ)·m_i1(Θ)+K'·δ_i(v_Θ,m)

Wherein：

K' is the revised conflict factor, δ in formula_i(v_n, m) it is conflict allocation proportion, m_i(2)(Θ) is general for uncertain set Rate is distributed.

Similarly, synthesis evidence source x_i1,x_i2,...,x_ij+1, following recurrence formula can be drawn：

m_i(j+1)(v_n)=m_i(j)(v_n)·m_ij+1(v_n)+

m_i(j)(v_n)·m_i(j)(Θ)+m_i(j)(Θ)·m_ij+1(v_n)

+K'·δ_i(v_n,m)

m_i(j+1)(Θ)=m_ij+1(Θ)·m_i(j)(Θ)+K'·δ_i(v_Θ,m)

The initial basic probability assignment of the first order can be obtained by above composition rule, with reference on evidence source conflict point The relevant knowledge matched somebody with somebody can obtain basic probability assignment of the first order overall target on Comment gathers V.Synthesis is advised more than again Distribution transformer assessment result can then be obtained.

Embodiment 2

Distribution transformer to somewhere carries out state estimation, its each component test information, patrol and examine information, operation information and Relative inferiority degree is shown in Table 1.

The distribution transformer related data of table 1

First primordium of the distribution transformer second level index evidence on Comment gathers V to be assessed is obtained using THE FUZZY EVALUATING METHOD This probability distribution, is shown in Table 2.

The initial basic probability assignment of each index of table 2

The analytic hierarchy process (AHP) of application enhancements calculates the weight of each layer index relative importance, and utilization formula (10) calculates it and puts Coefficient of reliability, is shown in Table 3

The index weights of table 3 and confidence level coefficient

By taking the synthesis of earthing or grounding means index of correlation evidence source as an example：The confidence level coefficient of earth resistance and down conductor outward appearance Respectively 1,0.580, initial evidence source is modified, m can be obtained₅₁(v₁)=0, m₅₁(v₂)=0.607, m₅₁(v₂)= 0.393, m₅₁(v₁)=0；m₅₂(v₁)=0.580, m₅₂(v₂)=0, m₅₂(v₃)=0, m₅₂(v₄)=0.By m can be obtained₅₍₂₎(v₁)= 0.124, m₅₍₂₎(v₂)=0.478, m₅₍₂₎(v₃)=0.165, m₅₍₂₎(v₄)=0, m₅₍₂₎(Θ)=0.091.

Each layer index is carried out synthesizing the basic probability assignment for finally giving distribution transformer by same step and method It is m (v₁)=0.213, m (v₂)=0.562, m (v₃)=0.121, m (v₄)=0, m (Θ)=0.104, thus judges the distribution The running status of transformer is " general " state, and the data to transformer are analyzed discovery, and only earth resistance and fuel tank is rotten Near demand value, other parts are all in preferable state for erosion.Using this distribution transformer essential information and service data After to its state estimation, monitoring is strengthened to this distribution transformer scoring lower position, the distribution transformer continuous service is very A period of time long, its each item data is just slightly decreased, but remains to normal operation.

It should be appreciated that the part that this specification is not elaborated belongs to prior art.

Although the specific embodiment of the invention above in association with Description of Drawings, those of ordinary skill in the art should Understand, these are merely illustrative of, and various deformation or modification can be made to these implementation methods, without departing from original of the invention Reason and essence.The scope of the present invention is only limited by the claims that follow.

With reference to following description and accompanying drawing, some particular implementations in the embodiment of the present invention are specifically disclosed, carry out table Show some modes for the principle for implementing embodiments of the invention, but it is to be understood that the scope of embodiments of the invention does not receive this Limitation.Conversely, embodiments of the invention include fall into attached claims spirit and intension in the range of all changes, Modification and equivalent.

Claims (5)

1. it is a kind of based on the distribution transformer state evaluating method for improving evidential reasoning fusion, it is characterised in that including following step Suddenly：

Step 1, according to distribution transformer Test Information to be assessed, patrol and examine information, the data of operation information, set up distribution transformer Device state estimation two-level index system；

Step 2, distribution transformer second level index evidence to be assessed is obtained using THE FUZZY EVALUATING METHOD on the initial of Comment gathers V Basic probability assignment；

Step 3, determine the weight of each layer index relative importance using improved H, and it calculated using formula to put Coefficient of reliability；

Step 4, by confidence level coefficient to initial evidence source change obtain basic probability assignment；

Step 5, evidence fusion is carried out using improved evidential reasoning composition rule, so as to obtain the final shape of distribution transformer State.

2. as claimed in claim 1 based on the distribution transformer state evaluating method for improving evidential reasoning fusion, its feature exists In the specific method of the step 2 is as follows：

1) the Comment gathers V is divided into good, general, attention, abnormal four kinds of different conditions, V={ v₁,v₂,v₃,v₄}={ is good Good, general, attention, exception }；

2) degree of membership of the evaluation index for Comment gathers is determined；Comprise the following steps：

A. the evaluation index that can directly quantify is determined using relative inferiority degree；

B. ambiguity, it is impossible to which, using detailed bonus point table is formulated, the evaluation index is according to bonus point table for the evaluation index of quantification treatment Bonus point, its state is quantified.

3. as claimed in claim 1 based on the distribution transformer state evaluating method for improving evidential reasoning fusion, its feature exists In the computing formula of confidence level coefficient is described in step 3：

β_ij=w_ij/w_ik(1)；

β in formula (1)_ijIt is confidence level coefficient, the lower floor single index { x of 1 grade of index i_i1,x_i2,...,x_ij..., x_iJPower { w is respectively again_i1,w_i2,...,w_ij,...,w_iJ, w_ikIt is then the maximum of above-mentioned weighted value.

4. as claimed in claim 1 based on the distribution transformer state evaluating method for improving evidential reasoning fusion, its feature exists In basic probability assignment formula is described in step 4：

m_ij(v_n)=β_ijμ_ij,n(2)；

M in formula (2)_ij(v_n) it is basic probability assignment, β_ijIt is confidence level coefficient, μ_ij,nIt is probability assignment.

5. as claimed in claim 1 based on the distribution transformer state evaluating method for improving evidential reasoning fusion, its feature exists In improved evidential reasoning composition rule is described in step 5：

$\begin{array}{c}{m}_{i(j+1)}\left(v_n\right)=m_{i\left(j\right)}\left(v_n\right)\·m_{ij+1}\left(v_n\right)+m_{i\left(j\right)}\left(v_n\right)\·m_{i\left(j\right)}\left(\mathrm{\Θ}\right)+\\ m_{i\left(j\right)}\left(\mathrm{\Θ}\right)\·m_{ij+1}\left(v_n\right)+K^{\′}\·{\mathrm{\δ}}_i(v_n,m)\end{array}---\left(3\right);$

m_i(j+1)(Θ)=m_ij+1(Θ)·m_i(j)(Θ)+K'·δ_i(v_Θ,m) (4)；

K' is the revised conflict factor, δ in formula (3), (4)_i(v_Θ, m) it is conflict allocation proportion, m_i(j+1)(Θ) is uncertain Set probability assignments.