CN105225021A - The optimum choice method of power distribution network project yet to be built - Google Patents

Abstract

The invention discloses the optimum choice method of a kind of power distribution network project yet to be built, comprise the power distribution network present situation index and target indicator of analyzing project region yet to be built; Index is carried out classification; Quantum chemical method is carried out to index and calculates the weight of each index; Calculate the final scoring of each project yet to be built; According to credit requirement and the available funds total value of final scoring and each project yet to be built, calculate the optimum choice result of power distribution network project yet to be built.The present invention is owing to considering electrical network present situation index and the target indicator of Project Area yet to be built, quantification treatment is carried out to the lifting effect of electrical network index, and objective reality effect is formed the overall scores of projects in conjunction with expertise, and carry out the selection of final project yet to be built according to available funds total value and project score; Present invention, avoiding the blindness in item selection procedure yet to be built and randomness; The present invention is scientific and reasonable, workable.

Description

The optimum choice method of power distribution network project yet to be built

Technical field

The present invention is specifically related to the optimum choice method of a kind of power distribution network project yet to be built.

Background technology

Along with the development of national economy, living standards of the people are promoted steadily and are improved, electric load sustainable growth, and the pressure faced by power grid construction highlights day by day, especially power distribution network.Power distribution network, directly in the face of the terminal link of power consumer, is promote important step that is economic, that improve People's livelihood.

A lot of constraint is there is in the construction of power distribution network and planning process.At present, the construction object of national grid to power distribution network has clear and definite regulation, and every planning index of relating to power distribution network is all with the quantification in addition of the forms such as directive/guide.But the project that can build of each year is limited, can not build all items, determines that the process of all kinds of project yet to be built then there is no according to following at present, cause the construct effects of biology relating to China's power distribution network to need further lifting.

Summary of the invention

The object of the present invention is to provide a kind of optimum choice method can carrying out the power distribution network project yet to be built of items selection yet to be built according to the beneficial effect of distribution network construction target, power distribution network project yet to be built.

The optimum choice method of this power distribution network provided by the invention project yet to be built, comprises the steps:

S1. power distribution network present situation index and the target indicator of project region yet to be built is analyzed;

S2. according to target indicator significance level, the index that step S1 obtains is carried out classification;

S3. to the graded index that step S2 obtains, quantum chemical method is carried out:

Quantum chemical method comprise carry out significance level classification according to the improvement degree of graded index to power distribution network present situation and the fuzzy evaluation of marking calculate, carry out according to the improvement numerical value of graded index to power distribution network present situation function calculating numerical Evaluation and according to graded index to power distribution network present situation with or without improving the logic evaluation of giving a mark;

S4. to the graded index that step S2 obtains, the weight of each index is calculated;

S5. to quantum chemical method result and the index weights of step S3 and S4 acquisition, the final scoring of each project yet to be built is calculated;

The final scoring of the project yet to be built S6. obtained according to step S5, and the credit requirement of each project yet to be built and available funds total value, calculate the optimum choice result of power distribution network project yet to be built.

Index described in step S1, comprises the power supply quality indexs such as integrated voltage qualification rate, low-voltage user ratio, line powering radius, the average power off time of system, customer outage hours; Distribution transformer capacity specification rate, circuit section specification rate, cable rate, insulation rate, non-crystaline amorphous metal join the horizontal indexs of equipment and technology such as number; The electric network composition index such as transformer station's single main transformer single supply accounting, transformer station's contact rate, circuits per unit area length, network connection typical case rate, circuit contact rate, the heavy Overflow RateHT of circuit; The heavy load service capability index such as Overflow RateHT, capacity-load ratio, per family capacity of distribution transform of main transformer " N-1 " percent of pass, circuit " N-1 " percent of pass, load transfer plan ability, main transformer.

Classification described in step 2, comprises first class index and two-level index, and first class index comprises power supply quality, equipment and technology level, load service capability and electric network composition, two-level index comprises raising integrated voltage qualification rate, solve the distribution transforming of high damage, solve low-voltage user ratio, reduction high-tension line radius of electricity supply, reduction medium-voltage line radius of electricity supply, the average power off time of minimizing system, promote distribution transformer capacity specification rate, promote high-tension line cross-section gauge generalized rate, promote medium-voltage line cross-section gauge generalized rate, promote cable rate, promote insulation rate, " Every household has an ammeter " rate of lifting, reduce line loss, employing non-crystaline amorphous metal is joined, solve the single main transformer of transformer station, solve transformer station's single supply, improve transformer station's contact rate, promote circuits per unit area length, promote network connection typical case rate, improve medium-voltage line contact rate, solve the heavy Overflow RateHT of high-tension line, solve the heavy Overflow RateHT of medium-voltage line, improve high voltage distribution network " N-1 " percent of pass, improve medium-voltage line " N-1 " percent of pass, improve load transfer plan, improve the heavy Overflow RateHT of main transformer, improve capacity-load ratio and promote capacity of distribution transform per family.

Quantum chemical method described in step 3, for according to different indexs, adopts fuzzy evaluation, numerical Evaluation and logic evaluation to carry out quantum chemical method, specifically comprises:

Fuzzy evaluation is carry out social estate system scoring according to the improvement degree of graded index to power distribution network present situation to the significance level of index, the index of fuzzy evaluation rule is adopted to have: to improve integrated voltage qualification rate, solve the distribution transforming of high damage, reduction high-tension line radius of electricity supply, reduction medium-voltage line radius of electricity supply, the average power off time of minimizing system, promote distribution transformer capacity specification rate, promote high-tension line cross-section gauge generalized rate, promote medium-voltage line cross-section gauge generalized rate, promote cable rate, promote insulation rate, " Every household has an ammeter " rate of lifting, reduce line loss, improve transformer station's contact rate, promote circuits per unit area length, promote network connection typical case rate, improve medium-voltage line contact rate, solve the heavy Overflow RateHT of high-tension line, solve the heavy Overflow RateHT of medium-voltage line, improve high voltage distribution network " N-1 " percent of pass, improve medium-voltage line " N-1 " percent of pass, improve load transfer plan, improve the heavy Overflow RateHT of main transformer,

Numerical Evaluation is the numerical Evaluation of carrying out function calculating according to the improvement numerical value of graded index to power distribution network present situation, directly adopting numerical evaluation, evaluating result of calculation accordingly according to calculating with minor function:

Solve low-voltage user ratio: $\left\{\begin{array}{c}0.4x+60;75<x\&le;100\\ 0.8x+28;50<x\&le;75\\ 1.36x;x\&le;50\end{array}\right.;$

Improve capacity-load ratio: $\left\{\begin{array}{c}100;x>1.9\\ 111x-111;1<x\&le;1.9\\ 0;x<1\end{array}\right.;$

Promote capacity of distribution transform per family: $\left\{\begin{array}{c}100;x>70\\ 0.5x+65;50<x\&le;70\\ 1.5x+15;30<x\&le;50\\ 2x;0\&le;x<30\end{array}\right.;$

The logic evaluation that logic is evaluated as and gives a mark with or without improvement to power distribution network present situation according to graded index, directly adopt two-valued function to evaluate index, evaluation result " is or has " to correspond to 100, and evaluation result " no or nothing " corresponds to 0; Adopt the index of logic evaluation to comprise employing non-crystaline amorphous metal to attach troops to a unit, solve the single main transformer of transformer station and solve transformer station's single supply.

Weight described in step 4 is combining weights, comprises subjective weight and objective weight; Subjective weight adopts analytical hierarchy process to calculate; Objective weight adopts entropy assessment to calculate; Weight, subjective weight, objective weight meet following formula:

Weight=0.6 × subjective weight+0.4 × objective weight

Described analytical hierarchy process calculates subjective weight, comprises the steps:

1). first according to 1-9 grade reciprocity scaling theory, construct judgment matrix between two, B=(b _ij) _{n × n}, b _ij>0, b _ij=1/b _ij, b _ijrepresent i-th index and a jth index relative importance; Assuming that factor A in A layer _kwith index B in next level ₁, B ₂b _nimportance compare between two, then the judgment matrix B=(b constructed _ij) _{n × n}, b _ij>0, b _ij=1/b _ij, b _iirepresent the important ratio of self comparatively, therefore b _ii=1, namely judgment matrix diagonal line is all 1.Judgment matrix is as follows between two:

$B=\left[\begin{array}{cccc}1& b_{12}& ...& b_{1n}\\ b_{21}& 1& ...& b_{2n}\\ ...& ...& ...& ...\\ b_{n1}& b_{n2}& ...& 1\end{array}\right]$

1-9 reciprocity scale quantization table is as following table:

Grade	1	3	5	7	9
						The degree that language describes	Of equal importance	Important a little	Obviously important	Strongly important	Extremely important

In table, other grades, the i.e. intermediate value of the above-mentioned adjacent description degree of 2,4,6,8 expression.

2). eigenvalue of maximum and the proper vector of judgment matrix is calculated according to judgment matrix.

Random index CR is adopted to weigh the degree of consistency of judgment matrix.Computing method are as follows: the Maximum characteristic root λ first calculating judgment matrix _max, coincident indicator ratio CI=(λ _max-n)/(n-1), according to judgment matrix exponent number n, from following table, inquire about corresponding Aver-age Random Consistency Index RI, last CR=CI/RI.

n	1	2	3	4	5	6	7	8	9
										RI	0.00	0.00	0.58	0.90	1.12	1.24	1.32	1.41	1.45

When CR is less than 0.1, think that judgment matrix meets coherence request.1,2 rank judgment matrixs are without the need to judging consistance.After judgment matrix approach verification is qualified, solve the weight of judgment matrix; No person needs the Partial Elements redefining judgment matrix, until judgment matrix mean random consistency desired result is qualified.

3). by the n rank judgment matrix going out to meet consistency check above, first determine the product of this each row element of matrix then M is calculated _in th Root V _i, to vectorial V _inormalization vectorial W=(the W obtained ₁, W ₂..., W _n) ^tbe the weight factor vector of required certain layer of each element.The method of above-mentioned steps is utilized to obtain the weight factor of every layer of index.

Described entropy assessment calculates objective weight, comprises the steps:

1). the object of evaluation has M=(M ₁, M ₂... M _m), the index D=(D of evaluation ₁, D ₂..., D _n), form judgment matrix as follows:

$V=\left[\begin{array}{cccc}{V}_{11}& V_{12}& ...& V_{1n}\\ V_{21}& V_{21}& ...& V_{2n}\\ ...& ...& ...& ...\\ V_{m1}& V_{m2}& ...& V_{mn}\end{array}\right]$

2). determine the formula of objective weight, represent the Characteristic Ratios of a jth index of i-th evaluation object, then calculate represent the entropy of a jth index,

3). finally obtain represent the objective weight of a jth index.

The optimum choice result calculating power distribution network project yet to be built described in step S6, the result of calculation for following data model:

min{C(u _j)|u _j∈U}

$p\left(u_j\right)=\underset{1}{\overset{n}{\&Sigma;}}{w}_{i}p\left(u_{ij}\right)$

$C\left(u_j\right)=\frac{M\left(u_j\right)}{p\left(u_j\right)}$

Optimization aim: i=1 ..., n; J=1 ..., m

Constraint condition: $\underset{1}{\overset{t}{\&Sigma;}}M\left(u_j\right)\&le;Y$

Wherein, C (u _j) represent the unit effect credit requirement of a jth project, p (u _j) be the final scoring score value of a jth project, p (u _ij) be the scoring score value of i-th index of a jth project, w _ibe the weight of i-th index, M (u _j) be the credit requirement of a jth project, t is front t project yet to be built of unit effect credit requirement sequence, and be namely selected in t project yet to be built, Y is available funds total value.

The present invention is owing to considering electrical network present situation index and the target indicator of Project Area yet to be built, quantification treatment is carried out to the lifting effect of electrical network index, and objective reality effect is calculated the overall scores forming each project in conjunction with expertise, and carry out the selection of final project yet to be built according to available funds total value and project score; The present invention effectively can carry out the selection of project yet to be built for the beneficial effect of each project yet to be built and available funds total value, avoid the blindness in item selection procedure yet to be built and randomness; The present invention is scientific and reasonable, workable.

Accompanying drawing explanation

Fig. 1 is method flow diagram of the present invention.

Fig. 2 is index system schematic diagram of the present invention.

Embodiment

As shown in Figure 1, be method flow diagram of the present invention: the optimum choice method of this power distribution network provided by the invention project yet to be built, comprises the steps:

S1. power distribution network present situation index and the target indicator of project region yet to be built is analyzed:

Described index comprises the power supply quality indexs such as integrated voltage qualification rate, low-voltage user ratio, line powering radius, the average power off time of system, customer outage hours; Distribution transformer capacity specification rate, circuit section specification rate, cable rate, insulation rate, non-crystaline amorphous metal join the horizontal indexs of equipment and technology such as number; The electric network composition index such as transformer station's single main transformer single supply accounting, transformer station's contact rate, circuits per unit area length, network connection typical case rate, circuit contact rate, the heavy Overflow RateHT of circuit; The heavy load service capability index such as Overflow RateHT, capacity-load ratio, per family capacity of distribution transform of main transformer " N-1 " percent of pass, circuit " N-1 " percent of pass, load transfer plan ability, main transformer.The schematic diagram of index system as shown in Figure 2.

S2. according to target indicator significance level, the index that step S1 obtains is carried out classification:

Described classification, comprises first class index and two-level index, and first class index comprises power supply quality, equipment and technology level, load service capability and electric network composition, two-level index comprises raising integrated voltage qualification rate, solve the distribution transforming of high damage, solve low-voltage user ratio, reduction high-tension line radius of electricity supply, reduction medium-voltage line radius of electricity supply, the average power off time of minimizing system, promote distribution transformer capacity specification rate, promote high-tension line cross-section gauge generalized rate, promote medium-voltage line cross-section gauge generalized rate, promote cable rate, promote insulation rate, " Every household has an ammeter " rate of lifting, reduce line loss, employing non-crystaline amorphous metal is joined, solve the single main transformer of transformer station, solve transformer station's single supply, improve transformer station's contact rate, promote circuits per unit area length, promote network connection typical case rate, improve medium-voltage line contact rate, solve the heavy Overflow RateHT of high-tension line, solve the heavy Overflow RateHT of medium-voltage line, improve high voltage distribution network " N-1 " percent of pass, improve medium-voltage line " N-1 " percent of pass, improve load transfer plan, improve the heavy Overflow RateHT of main transformer, improve capacity-load ratio and promote capacity of distribution transform per family.

S3. to the graded index that step S2 obtains, quantum chemical method is carried out:

Described quantum chemical method, for according to different indexs, adopts fuzzy evaluation, numerical Evaluation and logic evaluation to carry out quantum chemical method, specifically comprises:

Fuzzy evaluation is carry out social estate system scoring according to the improvement degree of graded index to power distribution network present situation to the significance level of index, grade is " A, B, C, D, E ", " A " corresponding 80 points, " B " corresponding 60 points, " C " corresponding 40 points, " D " corresponding 20 points, " E " corresponding 0 point, the index of fuzzy evaluation rule is adopted to have: to improve integrated voltage qualification rate, solve the distribution transforming of high damage, reduction high-tension line radius of electricity supply, reduction medium-voltage line radius of electricity supply, the average power off time of minimizing system, promote distribution transformer capacity specification rate, promote high-tension line cross-section gauge generalized rate, promote medium-voltage line cross-section gauge generalized rate, promote cable rate, promote insulation rate, " Every household has an ammeter " rate of lifting, reduce line loss, improve transformer station's contact rate, promote circuits per unit area length, promote network connection typical case rate, improve medium-voltage line contact rate, solve the heavy Overflow RateHT of high-tension line, solve the heavy Overflow RateHT of medium-voltage line, improve high voltage distribution network " N-1 " percent of pass, improve medium-voltage line " N-1 " percent of pass, improve load transfer plan, improve the heavy Overflow RateHT of main transformer,

Numerical Evaluation is the numerical Evaluation of carrying out function calculating according to the improvement numerical value of graded index to power distribution network present situation, directly adopting numerical evaluation, evaluating result of calculation accordingly according to calculating with minor function:

Solve low-voltage user ratio: $\left\{\begin{array}{c}0.4x+60;75<x\&le;100\\ 0.8x+28;50<x\&le;75\\ 1.36x;x\&le;50\end{array}\right.;$

Improve capacity-load ratio: $\left\{\begin{array}{c}100;x>1.9\\ 111x-111;1<x\&le;1.9\\ 0;x<1\end{array}\right.;$

Promote capacity of distribution transform per family: $\left\{\begin{array}{c}100;x>70\\ 0.5x+65;50<x\&le;70\\ 1.5x+15;30<x\&le;50\\ 2x;0\&le;x<30\end{array}\right.;$

The logic evaluation that logic is evaluated as and gives a mark with or without improvement to power distribution network present situation according to graded index, directly adopt two-valued function to evaluate index, evaluation result " is or has " to correspond to 100, and evaluation result " no or nothing " corresponds to 0; Adopt the index of logic evaluation to comprise employing non-crystaline amorphous metal to attach troops to a unit, solve the single main transformer of transformer station and solve transformer station's single supply.

S4. to the graded index that step S2 obtains, the weight of each index is calculated:

Described weight is combining weights, comprises subjective weight and objective weight; Subjective weight adopts analytical hierarchy process to calculate; Objective weight adopts entropy assessment to calculate; Weight, subjective weight, objective weight meet following formula:

Weight=0.6 × subjective weight+0.4 × objective weight

Described analytical hierarchy process calculates subjective weight, comprises the steps:

1). first according to 1-9 grade reciprocity scaling theory, construct judgment matrix between two, B=(b _ij) _{n × n}, b _ij>0, b _ij=1/b _ij, b _ijrepresent i-th index and a jth index relative importance; Assuming that factor A in A layer _kwith index B in next level ₁, B ₂b _nimportance compare between two, then the judgment matrix B=(b constructed _ij) _{n × n}, b _ij>0, b _ij=1/b _ij, b _iirepresent the important ratio of self comparatively, therefore b _ii=1, namely judgment matrix diagonal line is all 1.Judgment matrix is as follows between two:

$B=\left[\begin{array}{cccc}1& b_{12}& ...& b_{1n}\\ b_{21}& 1& ...& b_{2n}\\ ...& ...& ...& ...\\ b_{n1}& b_{n2}& ...& 1\end{array}\right]$

1-9 reciprocity scale quantization table is as following table:

Grade	1	3	5	7	9
						The degree that language describes	Of equal importance	Important a little	Obviously important	Strongly important	Extremely important

In table, other grades, the i.e. intermediate value of the above-mentioned adjacent description degree of 2,4,6,8 expression.

2). eigenvalue of maximum and the proper vector of judgment matrix is calculated according to judgment matrix.

Random index CR is adopted to weigh the degree of consistency of judgment matrix.Computing method are as follows: the Maximum characteristic root λ first calculating judgment matrix _max, coincident indicator ratio CI=(λ _max-n)/(n-1), according to judgment matrix exponent number n, from following table, inquire about corresponding Aver-age Random Consistency Index RI, last CR=CI/RI.

n	1	2	3	4	5	6	7	8	9
										RI	0.00	0.00	0.58	0.90	1.12	1.24	1.32	1.41	1.45

When CR is less than 0.1, think that judgment matrix meets coherence request.1,2 rank judgment matrixs are without the need to judging consistance.After judgment matrix approach verification is qualified, solve the weight of judgment matrix; No person needs the Partial Elements redefining judgment matrix, until judgment matrix mean random consistency desired result is qualified.

3). by the n rank judgment matrix going out to meet consistency check above, first determine the product of this each row element of matrix then M is calculated _in th Root V _i, to vectorial V _inormalization vectorial W=(the W obtained ₁, W ₂..., W _n) ^tbe the weight factor vector of required certain layer of each element.The method of above-mentioned steps is utilized to obtain the weight factor of every layer of index.

Described entropy assessment calculates objective weight, comprises the steps:

1). the object of evaluation has M=(M ₁, M ₂... M _m), the index D=(D of evaluation ₁, D ₂..., D _n), form judgment matrix as follows:

$V=\left[\begin{array}{cccc}{V}_{11}& V_{12}& ...& V_{1n}\\ V_{21}& V_{21}& ...& V_{2n}\\ ...& ...& ...& ...\\ V_{m1}& V_{m2}& ...& V_{mn}\end{array}\right]$

2). determine the formula of objective weight, represent the Characteristic Ratios of a jth index of i-th evaluation object, then calculate represent the entropy of a jth index,

3). finally obtain represent the objective weight of a jth index.

S5. to quantum chemical method result and the index weights of step S3 and S4 acquisition, the final scoring of each project yet to be built is calculated;

The final scoring of the project yet to be built S6. obtained according to step S5, and the credit requirement of each project yet to be built and available funds total value, calculate the optimum choice result of power distribution network project yet to be built.

The described optimum choice result calculating power distribution network project yet to be built, the result of calculation for following data model:

min{C(u _j)|u _j∈U}

$p\left(u_j\right)=\underset{1}{\overset{n}{\&Sigma;}}{w}_{i}p\left(u_{ij}\right)$

$C\left(u_j\right)=\frac{M\left(u_j\right)}{p\left(u_j\right)}$

Optimization aim: i=1 ..., n; J=1 ..., m

Constraint condition: $\underset{1}{\overset{t}{\&Sigma;}}M\left(u_j\right)\&le;Y$

Wherein, C (u _j) represent the unit effect credit requirement of a jth project, p (u _j) be the final scoring score value of a jth project, p (u _ij) be the scoring score value of i-th index of a jth project, w _ibe the weight of i-th index, M (u _j) be the credit requirement of a jth project, t is front t project yet to be built of unit effect credit requirement sequence, and be namely selected in t project yet to be built, Y is available funds total value.

Claims (8)

1. an optimum choice method for power distribution network project yet to be built, comprises the steps:

S1. power distribution network present situation index and the target indicator of project region yet to be built is analyzed;

S2. according to target indicator significance level, the index that step S1 obtains is carried out classification;

S3. to the graded index that step S2 obtains, quantum chemical method is carried out:

Quantum chemical method comprise carry out significance level classification according to the improvement degree of graded index to power distribution network present situation and the fuzzy evaluation of marking calculate, carry out according to the improvement numerical value of graded index to power distribution network present situation function calculating numerical Evaluation and according to graded index to power distribution network present situation with or without improving the logic evaluation of giving a mark;

S4. to the graded index that step S2 obtains, the weight of each index is calculated;

S5. to quantum chemical method result and the index weights of step S3 and S4 acquisition, the final scoring of each project yet to be built is calculated;

The final scoring of the project yet to be built S6. obtained according to step S5, and the credit requirement of each project yet to be built and available funds total value, calculate the optimum choice result of power distribution network project yet to be built.

2. according to the optimum choice method of the project yet to be built of the power distribution network shown in claim 1, it is characterized in that the index described in step S1, comprise the power supply quality indexs such as integrated voltage qualification rate, low-voltage user ratio, line powering radius, the average power off time of system, customer outage hours; Distribution transformer capacity specification rate, circuit section specification rate, cable rate, insulation rate, non-crystaline amorphous metal join the horizontal indexs of equipment and technology such as number; The electric network composition index such as transformer station's single main transformer single supply accounting, transformer station's contact rate, circuits per unit area length, network connection typical case rate, circuit contact rate, the heavy Overflow RateHT of circuit; The heavy load service capability index such as Overflow RateHT, capacity-load ratio, per family capacity of distribution transform of main transformer " N-1 " percent of pass, circuit " N-1 " percent of pass, load transfer plan ability, main transformer.

3. according to the optimum choice method of the project yet to be built of the power distribution network shown in claim 1, it is characterized in that the classification described in step 2, comprise first class index and two-level index, first class index comprises power supply quality, equipment and technology level, load service capability and electric network composition, two-level index comprises raising integrated voltage qualification rate, solve the distribution transforming of high damage, solve low-voltage user ratio, reduction high-tension line radius of electricity supply, reduction medium-voltage line radius of electricity supply, the average power off time of minimizing system, promote distribution transformer capacity specification rate, promote high-tension line cross-section gauge generalized rate, promote medium-voltage line cross-section gauge generalized rate, promote cable rate, promote insulation rate, " Every household has an ammeter " rate of lifting, reduce line loss, employing non-crystaline amorphous metal is joined, solve the single main transformer of transformer station, solve transformer station's single supply, improve transformer station's contact rate, promote circuits per unit area length, promote network connection typical case rate, improve medium-voltage line contact rate, solve the heavy Overflow RateHT of high-tension line, solve the heavy Overflow RateHT of medium-voltage line, improve high voltage distribution network " N-1 " percent of pass, improve medium-voltage line " N-1 " percent of pass, improve load transfer plan, improve the heavy Overflow RateHT of main transformer, improve capacity-load ratio and promote capacity of distribution transform per family.

4. according to the optimum choice method of the project yet to be built of the power distribution network shown in claim 1, it is characterized in that the quantum chemical method described in step 3, for according to different indexs, adopt fuzzy evaluation, numerical Evaluation and logic evaluation to carry out quantum chemical method, specifically comprise:

Fuzzy evaluation is carry out social estate system scoring according to the improvement degree of graded index to power distribution network present situation to the significance level of index, the index of fuzzy evaluation rule is adopted to have: to improve integrated voltage qualification rate, solve the distribution transforming of high damage, reduction high-tension line radius of electricity supply, reduction medium-voltage line radius of electricity supply, the average power off time of minimizing system, promote distribution transformer capacity specification rate, promote high-tension line cross-section gauge generalized rate, promote medium-voltage line cross-section gauge generalized rate, promote cable rate, promote insulation rate, " Every household has an ammeter " rate of lifting, reduce line loss, improve transformer station's contact rate, promote circuits per unit area length, promote network connection typical case rate, improve medium-voltage line contact rate, solve the heavy Overflow RateHT of high-tension line, solve the heavy Overflow RateHT of medium-voltage line, improve high voltage distribution network " N-1 " percent of pass, improve medium-voltage line " N-1 " percent of pass, improve load transfer plan, improve the heavy Overflow RateHT of main transformer,

Numerical Evaluation is the numerical Evaluation of carrying out function calculating according to the improvement numerical value of graded index to power distribution network present situation, directly adopting numerical evaluation, evaluating result of calculation accordingly according to calculating with minor function:

Solve low-voltage user ratio:

Improve capacity-load ratio:

Promote capacity of distribution transform per family:

The logic evaluation that logic is evaluated as and gives a mark with or without improvement to power distribution network present situation according to graded index, directly adopt two-valued function to evaluate index, evaluation result " is or has " to correspond to 100, and evaluation result " no or nothing " corresponds to 0; Adopt the index of logic evaluation to comprise employing non-crystaline amorphous metal to attach troops to a unit, solve the single main transformer of transformer station and solve transformer station's single supply.

5., according to the optimum choice method of the project yet to be built of the power distribution network shown in claim 1, it is characterized in that the weight described in step 4 is combining weights, comprise subjective weight and objective weight; Subjective weight adopts analytical hierarchy process to calculate; Objective weight adopts entropy assessment to calculate; Weight, subjective weight, objective weight meet following formula:

Weight=0.6 × subjective weight+0.4 × objective weight.

6., according to the optimum choice method of the project yet to be built of the power distribution network shown in claim 5, it is characterized in that described analytical hierarchy process calculates subjective weight, comprise the steps:

1). first according to 1-9 grade reciprocity scaling theory, construct judgment matrix between two, B=(b _ij) _{n × n}, b _ij>0, b _ij=1/b _ij, b _ijrepresent i-th index and a jth index relative importance; Assuming that factor A in A layer _kwith index B in next level ₁, B ₂b _nimportance compare between two, then the judgment matrix B=(b constructed _ij) _{n × n}, b _ij>0, b _ij=1/b _ij, b _iirepresent the important ratio of self comparatively, therefore b _ii=1, namely judgment matrix diagonal line is all 1.Judgment matrix is as follows between two:

1-9 reciprocity scale quantization table is as following table:

Grade 1 3 5 7 9

The degree that language describes Of equal importance Important a little Obviously important Strongly important Extremely important

In table, other grades, the i.e. intermediate value of the above-mentioned adjacent description degree of 2,4,6,8 expression.

2). eigenvalue of maximum and the proper vector of judgment matrix is calculated according to judgment matrix.

Random index CR is adopted to weigh the degree of consistency of judgment matrix.Computing method are as follows: the Maximum characteristic root λ first calculating judgment matrix _max, coincident indicator ratio CI=(λ _max-n)/(n-1), according to judgment matrix exponent number n, from following table, inquire about corresponding Aver-age Random Consistency Index RI, last CR=CI/RI.

n 1 2 3 4 5 6 7 8 9 RI 0.00 0.00 0.58 0.90 1.12 1.24 1.32 1.41 1.45

When CR is less than 0.1, think that judgment matrix meets coherence request.1,2 rank judgment matrixs are without the need to judging consistance.After judgment matrix approach verification is qualified, solve the weight of judgment matrix; No person needs the Partial Elements redefining judgment matrix, until judgment matrix mean random consistency desired result is qualified.

3). by the n rank judgment matrix going out to meet consistency check above, first determine the product of this each row element of matrix then M is calculated _in th Root V _i, to vectorial V _inormalization vectorial W=(the W obtained ₁, W ₂..., W _n) ^tbe the weight factor vector of required certain layer of each element.The method of above-mentioned steps is utilized to obtain the weight factor of every layer of index.

7., according to the optimum choice method of the project yet to be built of the power distribution network shown in claim 5, it is characterized in that described entropy assessment calculates objective weight, comprise the steps:

1). the object of evaluation has M=(M ₁, M ₂... M _m), the index D=(D of evaluation ₁, D ₂..., D _n), form judgment matrix as follows:

2). determine the formula of objective weight, represent the Characteristic Ratios of a jth index of i-th evaluation object, then calculate represent the entropy of a jth index,

3). finally obtain represent the objective weight of a jth index.

8., according to the optimum choice method of the project yet to be built of the power distribution network shown in claim 1, it is characterized in that the optimum choice result calculating power distribution network project yet to be built described in step S6, the result of calculation for following data model:

min{C(u _j)|u _j∈U}

Optimization aim: i=1 ..., n; J=1 ..., m

Constraint condition:

Wherein, C (u _j) represent the unit effect credit requirement of a jth project, p (u _j) be the final scoring score value of a jth project, p (u _ij) be the scoring score value of i-th index of a jth project, w _ibe the weight of i-th index, M (u _j) be the credit requirement of a jth project, t is front t project yet to be built of unit effect credit requirement sequence, and be namely selected in t project yet to be built, Y is available funds total value.