CN104022505A - Distribution network reconstruction method with important node voltage dip economic losses considered - Google Patents

Abstract

The invention discloses a distribution network reconstruction method with important node voltage dip economic losses considered. The distribution network reconstruction method includes the steps of determining and processing research objects, determining a gene coding rule and genetic algorithm related parameters, determining an objective function and constraint conditions for optimizing a problem, calculating the objective function, generating an optimal distribution network operation mode and the like. The distribution network reconstruction method with the important node voltage dip economic losses considered has the advantages that voltage dip economic loss evaluation based on a quality loss function is effectively merged into application of distribution network reconstruction in voltage dip, an expression of the problem is visual with the minimum economic losses as an objective, particularly, the gap that research analysis of important user nodes does not exist in distribution network construction based on voltage dip is filled through analysis of the important user nodes, and the important guiding significance and the important practical value are achieved.

Description

A kind of distribution reconstructing method of considering important node voltage dip economic loss

Technical field

The invention belongs to distribution network planning technical field, particularly relate to a kind of distribution reconstructing method of considering important node voltage dip economic loss.

Background technology

The activity in production of high-tech park extremely depends on the precision equipment extremely responsive to voltage dip, and the generation of voltage dip will bring serious economic loss to enterprise.Distribution reconstruct is to suppress the effective ways that voltage dip occurs, and the economic loss that the distribution reconstructing method of existing consideration voltage dip fails effectively to cause in conjunction with voltage dip is analyzed, and does not especially carry out this aspect research for responsible consumer node.For the angle protection important load from Electric Power Network Planning and operation, find certain economic loss that responsible consumer node is caused due to voltage dip and reach minimum distribution operational mode, there is great importance and practical value.

Summary of the invention

In order to address the above problem, the object of the present invention is to provide a kind of distribution reconstructing method of considering important node voltage dip economic loss.

In order to achieve the above object, the distribution reconstructing method of consideration important node voltage dip economic loss provided by the invention comprises the following step carrying out in order:

Step 1) research object determine and process the S01 stage:

Definite distribution network structure of studying and responsible consumer node, as research object, comprise system node and branch road information, system voltage grade, interconnection switch and block switch quantity and position, and process;

Step 2) gene code rule and definite S02 stage of genetic algorithm relevant parameter:

The decimal coded rule that gene code rule adopts; Genetic algorithm relevant parameter comprises Population Size, chromosome length, iterations, selection cross and variation probability;

Step 3) target function and definite S03 stage of constraints of optimization problem:

Target function is the economic loss that important user node causes due to voltage dip, and expression formula is:

$\mathrm{ObjV}\left(i\right)={\∫}_a^{b}L\left(x\right)f(x,\mathrm{\θ})\mathrm{dx}---\left(1\right)$

Wherein, ObjV is the array of stored target functional value;

I is chromosome sequence number, and its value is 1-popsize (popsize is race's size);

X is voltage dip amplitude;

A, b represents respectively lower limit and the upper limit of x, general a=0, b=0.9;

L (x) is voltage dip economic loss function;

F (x, θ) is the probability density of voltage dip amplitude x, the parameter that θ is distribution function;

Constraints is network loss constraint and voltage constraint, wherein:

Network loss constraint: △ P≤P _l* 5% (2)

Wherein, △ P is network loss, P _lfor the total load active power of power distribution network;

Voltage constraint: | U _n-U _i|≤U _n* 5% (3)

Wherein, U _nfor system rated voltage effective value, U _ifor node voltage effective value;

Step 4) S04 stage of calculating target function:

Carry out the calculating of target function in the S03 stage according to S01 stage, definite research object and parameter of S02 stage;

Step 5) generate S05 stage of optimum distribution operational mode:

To making the chromosome of target function value minimum decode and analyze, obtain optimum distribution operational mode.

In the S01 stage, the processing method of described research object is: definite research object is carried out to simulation modeling, the i.e. modeling in computer simulation software according to definite latticed form and parameter information, the setting of line correlation short trouble of going forward side by side, to directly call the simulation of simulation model for voltage dip by algorithm routine in genetic algorithm optimization process.

In the S02 stage, definite method of described gene code rule is: adopt decimal coded rule, first the switch of the whole network is numbered with natural number, and in the definite looped network of each interconnection switch, switch is numbered separately, from 1 to the total number of switches looped network; Value in the gene position of genetic coding is the switch number of opening in this looped network, and the value in gene position is restricted, must be positive integer, and from 1 to the total number of switches this looped network; Chromosome length equals interconnection switch number, i.e. looped network number; And take following simplified strategy:

1) if certain branch switch not in any looped network, it must be closed so;

2) words that, switch place branch road is connected with power supply point also should be closed.

In the S03 stage, in described target function, voltage dip economic loss function expression is as follows:

$L\left(x\right)=K\{1-\exp [-\frac{{(x-1.0)}^2}{{2\mathrm{\σ}}^2}\left]\right\}---\left(4\right)$

Wherein, the maximum loss value that K is quality loss function;

σ ²for sensitiveness parameter;

The unit outage cost of maximum loss value K and load is relevant, and formula is as follows:

K＝PC (5)

Wherein, P is node load active power;

C is the unit outage cost that voltage dip causes load;

In order to obtain sensitiveness parameter σ ², need to know the maximum loss value K of voltage dip, and certain voltage dip fall amplitude x ₀corresponding economic loss L ₀, obtain calculating the formula of sensitiveness parameter according to the expression formula of contrary normal state loss function thus as follows:

${\mathrm{\σ}}^2=\frac{{(x-1.0)}^2}{2\ln \left(\frac{K}{K-L_0}\right)}---\left(6\right)$

F (x in target function, θ) be the probability density of voltage dip amplitude x, θ is the parameter of distribution function, adopt the beta matching f (x, θ) that distributes, now θ is just embodied in α and β, by the temporary range of decrease value of voltage, x comes fitting parameter α and β, adopt maximum-likelihood method to carry out parameter fitting, now probability density can be designated as f (x), and expression formula is as follows:

The desired value of the economic loss function can calculating voltage after the approximation probability that obtains voltage dip accident distributes falling temporarily.

The beneficial effect of the distribution reconstructing method of consideration important node voltage dip economic loss provided by the invention: the voltage dip Economic loss evaluation based on quality loss function is dissolved into distribution reconstruct effectively in the application of voltage dip, make the expression of problem more directly perceived taking economic loss minimum as target, especially the analysis of important user node has been made up to the blank that the distribution reconstruct based on voltage dip is not researched and analysed for responsible consumer node, there is important directive significance and practical value.

Brief description of the drawings

Fig. 1 is the distribution reconstructing method flow chart of consideration important node voltage dip economic loss provided by the invention.

Embodiment

Below in conjunction with the drawings and specific embodiments, the distribution reconstructing method of consideration important node voltage dip economic loss provided by the invention is elaborated.

Technical scheme of the present invention and advantage are carried out to more detailed explanation herein, it should be pointed out that following explanation is only for explaining the present invention, instead of restriction the present invention.

As shown in Figure 1, the distribution reconstructing method of consideration important node voltage dip economic loss provided by the invention comprises the following step of carrying out in order:

Step 1) research object determine and process the S01 stage:

Definite distribution network structure of studying and responsible consumer node, as research object, comprise system node and branch road information, system voltage grade, and interconnection switch and block switch quantity and position etc., and process;

Step 2) gene code rule and definite S02 stage of genetic algorithm relevant parameter:

Because adopting genetic algorithm, the present invention is optimized, therefore first should determine gene code rule; Decimal coded rule coverage of the present invention all feasible solution mode, met chromosome conciliate between the requirement of unique mapping; Need in addition to arrange genetic algorithm relevant parameter, as Population Size, chromosome length, iterations, selection cross and variation probability etc.;

Step 3) target function and definite S03 stage of constraints of optimization problem:

Target function is the economic loss that important user node causes due to voltage dip, and expression formula is:

$\mathrm{ObjV}\left(i\right)={\∫}_a^{b}L\left(x\right)f(x,\mathrm{\θ})\mathrm{dx}---\left(1\right)$

Wherein, ObjV is the array of stored target functional value;

I is chromosome sequence number, and its value is 1-popsize (popsize is race's size);

X is voltage dip amplitude;

A, b represents respectively lower limit and the upper limit of x, general a=0, b=0.9;

L (x) is voltage dip economic loss function;

F (x, θ) is the probability density of voltage dip amplitude x, the parameter that θ is distribution function;

Constraints is network loss constraint and voltage constraint, wherein:

Network loss constraint: △ P≤P _l* 5% (2)

Wherein, △ P is network loss, P _lfor the total load active power of power distribution network;

Voltage constraint: | U _n-U _i|≤U _n* 5% (3)

Wherein, U _nfor system rated voltage effective value, U _ifor node voltage effective value;

Step 4) S04 stage of calculating target function:

Carry out the calculating of target function in the S03 stage according to S01 stage, definite research object and parameter of S02 stage, mainly comprise the content of two aspects:

1) frequency that responsible consumer node voltage falls temporarily and the calculating of corresponding temporary range of decrease value.To each distribution operational mode, set gradually the network node generation three phase short circuit fault except responsible consumer node, calculate voltage dip situation the record of responsible consumer Nodes;

2) use the appraisal procedure calculating based on quality loss function to fall temporarily the economic loss of bringing, the i.e. target function value of optimization problem according to the voltage dip data acquisition under each operational mode;

Step 5) generate S05 stage of optimum distribution operational mode:

To making the chromosome of target function value minimum decode and analyze, obtain optimum distribution operational mode.

In the S01 stage, the processing method of described research object is:

Definite research object is carried out to simulation modeling, the i.e. modeling in computer simulation software according to definite latticed form and parameter information, the setting of line correlation short trouble of going forward side by side, to directly call the simulation of simulation model for voltage dip by algorithm routine in genetic algorithm optimization process.

In the S02 stage, definite method of described gene code rule is:

Employing decimal coded rule, first numbers the switch of the whole network with natural number, and in the definite looped network of each interconnection switch, switch is numbered separately, from 1 to the total number of switches looped network; Value in the gene position of genetic coding is the switch number of opening in this looped network, and the value in gene position is restricted, must be positive integer, and from 1 to the total number of switches this looped network; Chromosome length equals interconnection switch number, i.e. looped network number; And take following simplified strategy:

1) if certain branch switch not in any looped network, it must be closed so;

2) words that, switch place branch road is connected with power supply point also should be closed;

Such coding rule has covered all feasible solution modes, has met the requirement of unique mapping between chromosome is conciliate.

In the S03 stage, definite method of described target function is:

L in target function (x) is voltage dip economic loss function, the Economic loss evaluation that Problem of Voltage Temporary-Drop causes with by quality fluctuation the essence of damnous assessment be identical, the present invention adopts the Economic loss evaluation of carrying out voltage dip based on the appraisal procedure of quality loss function, and adopt the contrary normal state loss function of combination property optimum, its expression formula is as follows:

$L\left(x\right)=K\{1-\exp [-\frac{{(x-1.0)}^2}{{2\mathrm{\σ}}^2}\left]\right\}---\left(4\right)$

Wherein, the maximum loss value that K is quality loss function;

σ ²for sensitiveness parameter;

The unit outage cost of maximum loss value K and load is relevant, and formula is as follows:

K＝PC (5)

Wherein, P is node load active power;

C is the unit outage cost that voltage dip causes load;

In order to obtain sensitiveness parameter σ ², need to know the maximum loss value K of voltage dip, and certain voltage dip fall amplitude x ₀corresponding economic loss L ₀, can obtain calculating the formula of sensitiveness parameter according to the expression formula of contrary normal state loss function thus as follows:

${\mathrm{\σ}}^2=\frac{{(x-1.0)}^2}{2\ln \left(\frac{K}{K-L_0}\right)}---\left(6\right)$

F (x in target function, θ) be the probability density of voltage dip amplitude x, θ is the parameter of distribution function, generally can adopt the beta matching f (x, θ) that distributes, now θ is just embodied in α and β, can come fitting parameter α and β with the temporary range of decrease value of voltage x, can adopt maximum-likelihood method to carry out parameter fitting, now probability density can be designated as f (x), and expression formula is as follows:

The desired value of the economic loss function can calculating voltage after the approximation probability that obtains voltage dip accident distributes falling temporarily.

In the S04 stage, in the computational process of described target function, it should be noted that: because circuit transmission range in power distribution network is shorter, and three-phase shortcircuit is the most serious short trouble, so can choose the three phase short circuit fault that the fault type of generation voltage dip is Nodes, but must be pointed out, choosing of various fault type can be reacted problem solved by the invention more comprehensively, truly, only need corresponding increase corresponding simulation modeling and algorithm routine; The present invention adopts improved dq algorithm to carry out the calculating of voltage dip amplitude and phase hit value, improves data that dq algorithm solved conventional dq algorithm and do not have the problem of simultaneity.

The present invention adopts the distribution reconstruction and optimization algorithm based on genetic algorithm, the operational mode that each is met to the constraint of network loss and node voltage is analyzed the voltage dip situation of responsible consumer node, calculate its possible information such as number of times and temporary range of decrease value of falling temporarily, and the economic loss that adopts the appraisal procedure based on quality loss function to cause voltage dip is assessed, taking this economic loss minimum as optimization aim, find best distribution operational mode.

Claims (4)

1. a distribution reconstructing method of considering important node voltage dip economic loss, is characterized in that: it comprises the following step carrying out in order:

Step 1) research object determine and process the S01 stage:

Definite distribution network structure of studying and responsible consumer node, as research object, comprise system node and branch road information, system voltage grade, interconnection switch and block switch quantity and position, and process;

Step 2) gene code rule and definite S02 stage of genetic algorithm relevant parameter:

The decimal coded rule that gene code rule adopts; Genetic algorithm relevant parameter comprises Population Size, chromosome length, iterations, selection cross and variation probability;

Step 3) target function and definite S03 stage of constraints of optimization problem:

Target function is the economic loss that important user node causes due to voltage dip, and expression formula is:

$\mathrm{ObjV}\left(i\right)={\∫}_a^{b}L\left(x\right)f(x,\mathrm{\θ})\mathrm{dx}---\left(1\right)$

Wherein, ObjV is the array of stored target functional value;

I is chromosome sequence number, and its value is 1-popsize (popsize is race's size);

X is voltage dip amplitude;

A, b represents respectively lower limit and the upper limit of x, general a=0, b=0.9;

L (x) is voltage dip economic loss function;

F (x, θ) is the probability density of voltage dip amplitude x, the parameter that θ is distribution function;

Constraints is network loss constraint and voltage constraint, wherein:

Network loss constraint: △ P≤P _l* 5% (2)

Wherein, △ P is network loss, P _lfor the total load active power of power distribution network;

Voltage constraint: | U _n-U _i|≤U _n* 5% (3)

Wherein, U _nfor system rated voltage effective value, U _ifor node voltage effective value;

Step 4) S04 stage of calculating target function:

Carry out the calculating of target function in the S03 stage according to S01 stage, definite research object and parameter of S02 stage;

Step 5) generate S05 stage of optimum distribution operational mode:

To making the chromosome of target function value minimum decode and analyze, obtain optimum distribution operational mode.

2. the distribution reconstructing method of consideration important node voltage dip economic loss according to claim 1, it is characterized in that: in the S01 stage, the processing method of described research object is: definite research object is carried out to simulation modeling, the i.e. modeling in computer simulation software according to definite latticed form and parameter information, the setting of line correlation short trouble of going forward side by side, to directly call the simulation of simulation model for voltage dip by algorithm routine in genetic algorithm optimization process.

3. the distribution reconstructing method of consideration important node voltage dip economic loss according to claim 1, it is characterized in that: in the S02 stage, definite method of described gene code rule is: adopt decimal coded rule, first the switch of the whole network is numbered with natural number, and in the definite looped network of each interconnection switch, switch is numbered separately, from 1 to the total number of switches looped network; Value in the gene position of genetic coding is the switch number of opening in this looped network, and the value in gene position is restricted, must be positive integer, and from 1 to the total number of switches this looped network; Chromosome length equals interconnection switch number, i.e. looped network number; And take following simplified strategy:

1) if certain branch switch not in any looped network, it must be closed so;

2) words that, switch place branch road is connected with power supply point also should be closed.

4. the distribution reconstructing method of consideration important node voltage dip economic loss according to claim 1, is characterized in that: in the S03 stage, in described target function, voltage dip economic loss function expression is as follows:

$L\left(x\right)=K\{1-\exp [-\frac{{(x-1.0)}^2}{{2\mathrm{\σ}}^2}\left]\right\}---\left(4\right)$

Wherein, the maximum loss value that K is quality loss function;

σ ²for sensitiveness parameter;

The unit outage cost of maximum loss value K and load is relevant, and formula is as follows:

K＝PC (5)

Wherein, P is node load active power;

C is the unit outage cost that voltage dip causes load;

In order to obtain sensitiveness parameter σ ², need to know the maximum loss value K of voltage dip, and certain voltage dip fall amplitude x ₀corresponding economic loss L ₀, obtain calculating the formula of sensitiveness parameter according to the expression formula of contrary normal state loss function thus as follows:

${\mathrm{\σ}}^2=\frac{{(x-1.0)}^2}{2\ln \left(\frac{K}{K-L_0}\right)}---\left(6\right)$

F (x in target function, θ) be the probability density of voltage dip amplitude x, θ is the parameter of distribution function, adopt the beta matching f (x, θ) that distributes, now θ is just embodied in α and β, by the temporary range of decrease value of voltage, x comes fitting parameter α and β, adopt maximum-likelihood method to carry out parameter fitting, now probability density can be designated as f (x), and expression formula is as follows:

The desired value of the economic loss function can calculating voltage after the approximation probability that obtains voltage dip accident distributes falling temporarily.