CN104821582A - Power distribution network load transfer optimization method and system based on non-linear integer programming - Google Patents

Abstract

The invention provides a power distribution network load transfer optimization method and system based on non-linear integer programming. The method comprises the following steps: mapping distribution feeders mutually associated in a power distribution network into a plurality of corresponding tree topology structure diagrams connected through analog switches; establishing a mathematical model according to the plurality of corresponding tree topology structure diagrams; calculating a variable value of an objective function in the mathematical model according to the mathematical model; and carrying out load transfer operation according to the variable value. Under the condition that faults occur in the power distribution network, power failure loss is the minimum; objective function and constraint conditions are expressed by specific mathematical expressions, and a standard nonlinear integer mathematic model is formed; a universal nonlinear integer programming algorithm is utilized to find a solution, and the found variable value is on and off combination of switch branches in the power distribution network; and thus the purpose of minimizing the influenced power failure area under a fault condition is realized.

Description

Distribution network load based on nonlinear integer programming turns for optimization method and system thereof

Technical field

The present invention relates to power system fault analysis method field, particularly a kind of distribution network load based on nonlinear integer programming turns for optimization method and system thereof.

Background technology

Along with China's rapid development of economy, more and more higher to the degree of dependence of electric power, the development of electric power safety has entered a brand-new stages of historical development.Electrical network is important infrastructure and the public utilities of relation national energy security and lifelines of the national economy, carries as socio-economic development and national economy provide important energy safeguard, the weighty responsibility of the promotion sustainable development of socio-economy.The reliability requirement of modern society to supply of electric power is more and more higher, and whenever all more important the status of power industry is than ever, electric power safety and be efficiently distinct issues.Distribution Network Equipment quantity is large, kind is many, power load distributing scope is wide, the complicated network structure, running has very large uncertainty, the generation of fault can not be avoided completely, therefore fully must study when breaking down in power distribution network how to reduce power failure as far as possible to the damnous problem of user power utilization.

Power distribution network is when break down (being generally short trouble); various relaying protection and automatics can detect that abnormal change occurs the voltage and current of relevant device; when this change reaches the operating value that various control appliance adjusts in advance; these control appliances will make appropriate action; on the one hand by Fault Isolation in rational scope; on the other hand due to the existence in Fault Isolation region; make those distance power supplys load more farther than area of isolation lose the path with former power supply node, thus also will have a power failure.By the closed interconnection switch often opened, these loads can be transferred in short-term the adjacent feeders be associated with former feeder line and power, shorten the time had a power failure, this i.e. load transfer.

From the mechanism of load transfer, if can be optimized combination for a certain specific fault to the branch road can making opening and closing movement, under can realizing fault condition, influenced power failure range minimizes.Due to electrical network, to have transient process extremely of short duration, requires that the Mathematical Modeling be optimized should be simple as far as possible, can be applied to analytical technology common in electrical network as far as possible, and can solve by the general optimized algorithm of Application comparison.This distribution network load based on nonlinear integer programming that the present invention proposes turns confession optimization method and system has important Research Significance and engineer applied is worth.

Summary of the invention

For above-mentioned problems of the prior art, the present invention proposes a kind of distribution network load based on nonlinear integer programming and turns for optimization method and system thereof, and under can realizing fault condition, influenced power failure range minimizes.

Distribution network load based on nonlinear integer programming turns for an optimization method, comprises the steps:

Each bar distribution feeder in power distribution network is mapped as corresponding each tree topology figure;

According to the interconnection switch connecting each bar distribution feeder, corresponding analog switch is set and connects described each tree topology figure;

Each tree topology figure founding mathematical models according to connection;

When breaking down, calculate the variate-value of described Mathematical Modeling;

Load transfer is carried out according to described variate-value.

Distribution network load based on nonlinear integer programming turns for an optimization system, comprising:

Mapping block, for being mapped as corresponding each tree topology figure by each bar distribution feeder in power distribution network;

Analog switch module, for according to the interconnection switch connecting each bar distribution feeder, arranges corresponding analog switch and connects described each tree topology figure;

Mathematical Modeling module, for each tree topology figure founding mathematical models according to connection;

Processing module, during for breaking down, calculating the variate-value of described Mathematical Modeling, carrying out load transfer according to described variate-value.

Distribution network load based on nonlinear integer programming of the present invention turns for optimization method and system thereof, the distribution feeder that is mutually related in power distribution network is mapped to the tree topology figure of the multiple correspondences connected by analog switch, according to the tree topology figure founding mathematical models of described multiple correspondence, according to described Mathematical Modeling, calculate the variate-value of target function in described Mathematical Modeling, carry out load transfer operation according to described variate-value; Make loss of outage minimum when breaking down in power distribution network, wherein target function and constraints all represent with clear and definite mathematic(al) representation, the non-linear integer Mathematical Modeling of formation standard, solve with general nonlinear integer programming algorithm, the variate-value solved be in power distribution network switching branches cut-off combination, thus the minimized object of influenced power failure range under realizing fault condition.

Accompanying drawing explanation

Fig. 1 is the flow chart that the distribution network load based on nonlinear integer programming of an embodiment turns for optimization method;

Fig. 2 is two tree topology connection layouts that the distribution network load based on nonlinear integer programming of an embodiment turns for optimization method;

Fig. 3 is the structural representation that the distribution network load based on nonlinear integer programming of an embodiment turns for optimization system.

Embodiment

In order to make the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing and specific embodiment, technical scheme of the present invention is further described.

Refer to the distribution network load based on nonlinear integer programming of an embodiment in Fig. 1 and turn the flow chart supplying optimization method.

Distribution network load based on nonlinear integer programming turns for an optimization method, comprises the steps:

Step S101, is mapped as corresponding each tree topology figure by each bar distribution feeder in power distribution network;

In one of them embodiment, every bar distribution feeder comprises at least one power end and at least one load side, is connected between different electrical power end, between power end with load side and between different load end by transmission line of alternation current, distribution transformer or switchgear.As an independently distribution feeder, have its load side independently in power supply and distribution feeder, wherein connected the conveying realizing electric current by transmission line of alternation current, the height that can be realized voltage by distribution transformer is changed mutually, circuit can disconnect by switchgear, isolated fault region.

In one of them embodiment, described each tree topology figure each bar distribution feeder in power distribution network being mapped as correspondence, method comprises:

The power end of described each bar distribution feeder and load side are mapped as the node of described tree topology figure;

Transmission line of alternation current, distribution transformer and switchgear are mapped as the branch road of described tree topology figure.

Tree topology figure adds that on bus network branch is formed, its transmission medium can You Duotiao branch, but do not form closed-loop path, there is certain fault-tolerant ability, the fault of a general branch node does not affect the work of another branch node, have and link simply, easy to maintenance, be easy to expansion, the advantages such as Fault Isolation is easier to, are mapped as corresponding each tree topology figure and more meet the link of distribution feeder load side simply by each bar distribution feeder in power distribution network, easy to maintenance, be easy to expansion, Fault Isolation such as to be easier at the characteristic.

Step S102, according to the interconnection switch connecting each bar distribution feeder, arranges corresponding analog switch and connects described each tree topology figure;

Power distribution network is when break down (being generally short trouble), various relaying protection and automatics can detect that abnormal change occurs the voltage and current of relevant device, when described change reaches the operating value that various control appliance presets, described control appliance will make appropriate action, on the one hand by fault section isolation in rational scope, on the other hand due to the existence in Fault Isolation region, make those distance power ends load side more farther than fault zone disconnect the connection with power end, thus also can have a power failure; And by the closed interconnection switch often opened, can load side more farther than fault zone for these distance power ends be transferred in the adjacent distribution feeder circuit be associated with former distribution feeder, powered by the power end of adjacent distribution feeder, thus realize load transfer.And according to connecting the interconnection switch of each bar distribution feeder, arranging corresponding analog switch connects described each tree topology figure, be the relation that each tree topology figure is connected to each other by analog switch by load transfer relationship map.

Step S103, each tree topology figure founding mathematical models according to connection;

Because electrical network has transient process and of short duration feature thereof, each tree topology figure founding mathematical models according to connection, each tree topology figure connected is converted into can the Mathematical Modeling of computing, by being optimized and computing Mathematical Modeling, can analyze the failure problems in electrical network as quick as thought, the loss of outage that distribution feeder is broken down in situation is minimum.

In one of them embodiment, described Mathematical Modeling, comprises target function and constraints, and described target function is nonlinear function.

In one of them embodiment, described target function is:

$min\underset{i=1}{\overset{n}{\Σ}}{(P_i^{SP}-P_i)}^2,$

Wherein, for the injecting power of known node i, P _ifor the injecting power of node i obtained with calculating formulae discovery, P _icomputing formula be:

$P_i=V_i\underset{j=1}{\overset{n}{\Σ}}{V}_j(G_{ij}{\mathrm{cos\δ}}_{ij}+B_{ij}{\mathrm{sin\δ}}_{ij}),$

Wherein, V _iand δ _ibe respectively amplitude and the phase angle of the voltage of node i, δ _ij=δ _i-δ _j, G _ijand B _ijbe respectively real part and the imaginary part of respective nodes admittance matrix element, described node admittance matrix is calculated as follows:

Y＝A·X·y _b·X·A ^T，

Wherein, A is the branch road incidence matrices of all described branch roads when running, y _bfor taking branch admittance as the diagonal matrix that diagonal entry is formed, described X is for being the diagonal matrix that diagonal entry is formed with membership, and its expression formula is:

Wherein, l is branch road sum in network, and described membership is: work as x _iwhen=1, branch road runs, and works as x _iwhen=0, branch road disconnects.

In described Mathematical Modeling, its node can be divided into power failure node and node two class that do not have a power failure, and the node that wherein do not have a power failure should meet power flow equation when steady operation, therefore its node imbalance power is that is the operation result in target function is zero; Power failure node is owing to disconnecting with power supply node, therefore its node injecting power is P _i=0, then its operation result in target function is as can be seen here, to make described target function minimum, the number of nodes that should make on the one hand not have a power failure is many as far as possible, and the power failure power of power failure node should be made little as far as possible on the other hand, the two acting in conjunction is the minimized object of influenced power failure range under can realizing fault condition.

Described constraints comprises the first constraints, the second constraints, the 3rd constraints and the 4th constraints;

Described first constraints is:

$I_k\≤I_k^{\max },$

I _kfor the real-time current value of a kth tree topology figure, for the lowest high-current value of a kth tree topology figure, wherein, I _kcan be calculated by following formula:

$I_k=\left|\frac{{\stackrel{\·}{V}}_{ks}-{\stackrel{\·}{V}}_{kt}}{z_{kst}}\right|,$

be respectively the voltage phasor of a kth tree topology figure, z _kstfor this branch impedance value;

Described second constraints is:

$V_i^{\min }\≤V_i\≤V_i^{\max },$

Wherein, with be respectively minimum amount of voltage that and the maximum voltage value of node i;

Described 3rd constraints is:

SumX=n-n _s-2, wherein sumX is the summation of X diagonal matrix elements, and n is node total number amount, n _sfor branch road quantity;

Described 4th constraints is:

X _f=0, wherein, f is the numbering of branch road of breaking down.

Visible, there is nonlinear function expression in the target function that described Mathematical Modeling comprises and constraints, the variate-value of Mathematical Modeling is 0/1 integer value, so Mathematical Modeling is nonlinear integer programming model, there is versatility, can solve with general nonlinear integer programming algorithm.

The target function of described Mathematical Modeling is minimised as target by the scope affected that has a power failure after breaking down in distribution feeder, can Specific amounts to turn to the gross power of all load buses in power supply interrupted district minimum, the quadratic sum being expressed as all node power difference is further minimum, for power supply interrupted district node, its injecting power is zero, its difference is the known load power of all nodes, power balance equation formula should be met for non-power supply interrupted district node, namely the known load power of non-power supply interrupted district node and the difference of its injecting power should be zero, therefore the node that can ensure not have a power failure is many as far as possible, the power of node of simultaneously having a power failure is minimum.

Step S104, when breaking down, calculates the variate-value of described Mathematical Modeling;

The variate-value calculated is 0/1 integer value, and " 0 " represents that branch road disconnects, and " 1 " represents that branch road closes, and described variate-value is the vector that all membership common combinations are formed.

Step S105, carries out load transfer according to described variate-value.

Described variate-value corresponds to the connection line with line disconnection ability in distribution feeder, operates the connection status of corresponding connection line, thus realize load transfer according to concrete variate-value.

Refer to Fig. 2, the distribution network load based on nonlinear integer programming of an embodiment turns two tree topology connection layouts for optimization method, the present embodiment for two 10kV distribution feeders connected each other to describe the technical scheme of load transfer optimization method under fault condition.

The first distribution feeder in power distribution network is mapped as corresponding tree topology Figure 24 0, wherein power end is mapped as the node 200 of tree topology figure, seven load sides are mapped as node 201, node 202, node 203, node 204, node 205, node 206, node 207 and node 208 respectively, node 202 is connected by branch road 222 with node 205, node 205 is connected by branch road 220 with node 206, node 205 is connected by branch road 221 with node 207, and all nodes that node 200 pairs of load sides that power end is corresponding are corresponding are powered; The second distribution feeder in power distribution network is mapped as corresponding tree topology Figure 25 0, wherein power end is mapped as the node 210 of tree topology figure, comprise the node that seven load sides map, one of them load side is mapped as node 217, and the node 217 that node 210 pairs of load sides that power end is corresponding are corresponding is powered; The branch road 230 that described node 207 is mapped by the connection line with line disconnection ability with node 217 is connected.

For tree topology Figure 24 0, the workload vector that there will be a known of the node that its seven load sides map is:

$P_1^{SP}={\left(\begin{array}{cccccccc}300& 450& 300& 280& 400& 300& 350& 400\end{array}\right)}^{T}kW,$

Branch resistance vector is:

R ₁＝(0.4 0.54 0.4 0.6 0.72 1 0.65 0.9) ^TΩ，

Branch road reactance vector is:

X ₁＝(0.3 0.65 0.3 0.35 0.75 0.55 0.35 0.5) ^TΩ；

For tree topology Figure 25 0, the workload vector that there will be a known of the node that each load side maps is:

$P_2^{SP}={\left(\begin{array}{cccccccc}300& 450& 300& 280& 400& 300& 350& 400\end{array}\right)}^{T}kW,$

Branch resistance vector is:

R ₂＝(0.4 0.54 0.4 0.6 0.72 1 0.65 0.9) ^TΩ，

Branch road reactance vector is:

X ₂＝(0.3 0.65 0.3 0.35 0.75 0.55 0.35 0.5) ^TΩ；

Suppose that described branch road 220 is short-circuited fault, then the target function of Mathematical Modeling is:

Constraints is: wherein, and the first constraints is:

$I_1=\left|\frac{{\stackrel{\·}{V}}_{1-0}-{\stackrel{\·}{V}}_{1-1}}{0.4+j0.3}\right|\≤I_1^{\max },I_2=\left|\frac{{\stackrel{\·}{V}}_{2-0}-{\stackrel{\·}{V}}_{2-1}}{0.4+j0.3}\right|\≤I_2^{\max };$

Second constraints is:

10(1-7％)＝9.3kV≤V _i≤10(1+7％)＝10.7kV；

3rd constraints is:

sumX＝n-n _s-2＝18-2-2＝14；

4th constraints is:

X ₂₂₀=0, represent that the variable of branch road 220 is " 0 ".

By described target function and constraints simultaneous, being the Mathematical Modeling of the load transfer method of the present embodiment setting fault, is the nonlinear integer programming model of standard.

Try to achieve the variate-value of described Mathematical Modeling, wherein, X ₂₂₀=0, X ₂₂₁=0, X ₂₂₂=0, X ₂₃₀remaining variate-value of=1, X is 1, and represent that branch road 220, branch road 221 and branch road 222 are off state, branch road 230 is closure state, and other branch road is closure state.

Therefore, load side in first distribution feeder of tree topology Figure 24 0 interior joint 205 and node 206 correspondence has a power failure, form minimum power failure range, node 207 is connected by the interconnection switch of branch road 230 correspondence with the load side of node 217 correspondence, the load side of node 207 correspondence is turned to be supplied in second distribution feeder at the load side place of node 217 correspondence, thus the minimized object of influenced power failure range under realizing fault condition.

Distribution network load based on nonlinear integer programming turns for an optimization system, comprising:

Mapping block 301, for being mapped as corresponding each tree topology figure by each bar distribution feeder in power distribution network;

Analog switch module 302, for according to the interconnection switch connecting each bar distribution feeder, arranges corresponding analog switch and connects described each tree topology figure;

Mathematical Modeling module 303, for each tree topology figure founding mathematical models according to connection;

Processing module 304, during for breaking down, calculating the variate-value of described Mathematical Modeling, carrying out load transfer according to described variate-value.

In one of them embodiment, described mapping block comprises:

Node mapping submodule, for being mapped as the power end of described each bar distribution feeder and load side the node of described tree topology figure;

Branch road mapping submodule, for being mapped as transmission line of alternation current, distribution transformer and switchgear the branch road of described tree topology figure.

In one of them embodiment, described Mathematical Modeling module comprises target function submodule and constraints submodule, and described target function submodule is nonlinear function.

In one of them embodiment, described target function submodule is:

$\min \underset{i=1}{\overset{n}{\mathrm{\Σ}}}{(P_i^{\mathrm{SP}}-P_i)}^2,$

Wherein, for the injecting power of known node i, P _ifor the injecting power of node i obtained with calculating formulae discovery, P _icomputing formula be:

$P_i=V_i\underset{j=1}{\overset{n}{\Σ}}{V}_j(G_{ij}{\mathrm{cos\δ}}_{ij}+B_{ij}{\mathrm{sin\δ}}_{ij}),$

Wherein, V _iand δ _ibe respectively amplitude and the phase angle of the voltage of node i, δ _ij=δ _i-δ _j, G _ijand B _ijbe respectively real part and the imaginary part of respective nodes admittance matrix element, described node admittance matrix is calculated as follows:

Y＝A·X·y _b·X·A ^T，

Wherein, A is the branch road incidence matrices of all described branch roads when running, y _bfor taking branch admittance as the diagonal matrix that diagonal entry is formed, described X is for being the diagonal matrix that diagonal entry is formed with membership, and its expression formula is:

Wherein, l is branch road sum in network, and described membership is: work as x _iwhen=1, branch road runs, and works as x _iwhen=0, branch road disconnects.

Described constraints submodule comprises the first constraints submodule, the second constraints submodule, the 3rd constraints submodule and the 4th constraints submodule; Wherein,

Described first constraints submodule is:

$I_k\≤I_k^{\max },$

I _kfor the real-time current value of a kth tree topology figure, for the lowest high-current value of a kth tree topology figure, wherein, I _kcan be calculated by following formula:

$I_k=\left|\frac{{\stackrel{\·}{V}}_{ks}-{\stackrel{\·}{V}}_{kt}}{z_{kst}}\right|,$

be respectively the voltage phasor of a kth tree topology figure, z _kstfor this branch impedance value;

Described second constraints submodule is:

$V_i^{\min }\≤V_i\≤V_i^{\max },$

Wherein, with be respectively minimum amount of voltage that and the maximum voltage value of node i;

Described 3rd constraints submodule is:

SumX=n-n _s-2, wherein, sumX is the summation of X diagonal matrix elements, and n is node total number amount, n _sfor branch road quantity;

Described 4th constraints submodule is:

X _f=0, wherein, f is the numbering of branch road of breaking down.

Can be found out by the scheme of above several embodiment, distribution network load based on nonlinear integer programming provided by the invention turns for optimization method and system thereof, the distribution feeder that is mutually related in power distribution network is mapped to the tree topology figure of the multiple correspondences connected by analog switch, according to the tree topology figure founding mathematical models of described multiple correspondence, according to described Mathematical Modeling, calculate the variate-value of target function in described Mathematical Modeling, carry out load transfer operation according to described variate-value; Make loss of outage minimum when breaking down in power distribution network, wherein target function and constraints all represent with clear and definite mathematic(al) representation, the non-linear integer Mathematical Modeling of formation standard, solve with general nonlinear integer programming algorithm, the variate-value solved be in power distribution network switching branches cut-off combination, thus the minimized object of influenced power failure range under realizing fault condition.

Each technical characteristic of the above embodiment can combine arbitrarily, for making description succinct, the all possible combination of each technical characteristic in above-described embodiment is not all described, but, as long as the combination of these technical characteristics does not exist contradiction, be all considered to be the scope that this specification is recorded.

The above embodiment only have expressed several execution mode of the present invention, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection range of patent of the present invention should be as the criterion with claims.

Claims (9)

1. the distribution network load based on nonlinear integer programming turns for an optimization method, it is characterized in that, comprises the steps:

Each bar distribution feeder in power distribution network is mapped as corresponding each tree topology figure;

According to the interconnection switch connecting each bar distribution feeder, corresponding analog switch is set and connects described each tree topology figure;

Each tree topology figure founding mathematical models according to connection;

When breaking down, calculate the variate-value of described Mathematical Modeling;

Load transfer is carried out according to described variate-value.

2. the distribution network load based on nonlinear integer programming according to claim 1 turns for optimization method, it is characterized in that, every bar distribution feeder comprises at least one power end and at least one load side, is connected between different electrical power end, between power end with load side and between different load end by transmission line of alternation current, distribution transformer or switchgear.

3. the distribution network load based on nonlinear integer programming according to claim 1 turns for optimization method, it is characterized in that, described each tree topology figure each bar distribution feeder in power distribution network being mapped as correspondence, and method comprises:

The power end of described each bar distribution feeder and load side are mapped as the node of described tree topology figure;

Transmission line of alternation current, distribution transformer and switchgear are mapped as the branch road of described tree topology figure.

4. the distribution network load based on nonlinear integer programming according to claim 1 turns for optimization method, and it is characterized in that described Mathematical Modeling comprises target function and constraints, described target function is nonlinear function.

5. the distribution network load based on nonlinear integer programming according to claim 4 turns for optimization method, and it is characterized in that, described target function is:

$\min \underset{i=1}{\overset{n}{\mathrm{\Σ}}}{({P_i}^{\mathrm{SP}}-P_i)}^2,$

Wherein, P _i ^sPfor the injecting power of known node i, P _ifor the injecting power of node i obtained with calculating formulae discovery, P _icomputing formula be:

$P_i=V_i\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{V}_j(G_{\mathrm{ij}}\cos {\mathrm{\δ}}_{\mathrm{ij}}+B_{\mathrm{ij}}\sin {\mathrm{\δ}}_{\mathrm{ij}}),$

Wherein, V _iand δ _ibe respectively amplitude and the phase angle of the voltage of node i, δ _ij=δ _i-δ _j, G _ijand B _ijbe respectively real part and the imaginary part of respective nodes admittance matrix element, described node admittance matrix is calculated as follows:

Y＝A·X·y _b·X·A ^T，

Wherein, A is the branch road incidence matrices of all described branch roads when running, y _bfor taking branch admittance as the diagonal matrix that diagonal entry is formed, described X is for being the diagonal matrix that diagonal entry is formed with membership, and its expression formula is:

Wherein, l is branch road sum in network, and described membership is: work as x _iwhen=1, branch road runs, and works as x _iwhen=0, branch road disconnects.

Described constraints comprises the first constraints, the second constraints, the 3rd constraints and the 4th constraints;

Described first constraints is:

$I_k\≤I_k^{\max },$

I _kfor the real-time current value of a kth tree topology figure, for the lowest high-current value of a kth tree topology figure, wherein, I _kcan be calculated by following formula:

$I_k=\left|\frac{{\stackrel{.}{V}}_{\mathrm{ks}}-{\stackrel{.}{V}}_{\mathrm{kt}}}{z_{\mathrm{kst}}}\right|,$

be respectively the voltage phasor of a kth tree topology figure, z _kstfor this branch impedance value;

Described second constraints is:

V _i ^min≤V _i≤V _i ^max，

Wherein, V _i ^minand V _i ^maxbe respectively minimum amount of voltage that and the maximum voltage value of node i;

Described 3rd constraints is:

SumX=n-n _s-2, wherein sumX is the summation of X diagonal matrix elements, and n is node total number amount, n _sfor branch road quantity;

Described 4th constraints is:

X _f=0, wherein, f is the numbering of branch road of breaking down.

6. the distribution network load based on nonlinear integer programming turns for an optimization system, it is characterized in that, comprising:

Mapping block, for being mapped as corresponding each tree topology figure by each bar distribution feeder in power distribution network;

Analog switch module, for according to the interconnection switch connecting each bar distribution feeder, arranges corresponding analog switch and connects described each tree topology figure;

Mathematical Modeling module, for each tree topology figure founding mathematical models according to connection;

Processing module, during for breaking down, calculating the variate-value of described Mathematical Modeling, carrying out load transfer according to described variate-value.

7. the distribution network load based on nonlinear integer programming according to claim 6 turns for optimization system, and it is characterized in that, described mapping block comprises:

Node mapping submodule, for being mapped as the power end of described each bar distribution feeder and load side the node of described tree topology figure;

Branch road mapping submodule, for being mapped as transmission line of alternation current, distribution transformer and switchgear the branch road of described tree topology figure.

8. the distribution network load based on nonlinear integer programming according to claim 6 turns for optimization system, and it is characterized in that, described Mathematical Modeling module comprises target function submodule and constraints submodule, and described target function submodule is nonlinear function.

9. the distribution network load based on nonlinear integer programming according to claim 8 turns for optimization system, and it is characterized in that, described target function submodule is:

$\min \underset{i=1}{\overset{n}{\mathrm{\Σ}}}{({P_i}^{\mathrm{SP}}-P_i)}^2,$

Wherein, P _i ^sPfor the injecting power of known node i, P _ifor the injecting power of node i obtained with calculating formulae discovery, P _icomputing formula be:

$P_i=V_i\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{V}_j(G_{\mathrm{ij}}\cos {\mathrm{\δ}}_{\mathrm{ij}}+B_{\mathrm{ij}}\sin {\mathrm{\δ}}_{\mathrm{ij}}),$

Wherein, V _iand δ _ibe respectively amplitude and the phase angle of the voltage of node i, δ _ij=δ _i-δ _j, G _ijand B _ijbe respectively real part and the imaginary part of respective nodes admittance matrix element, described node admittance matrix is calculated as follows:

Y＝A·X·y _b·X·A ^T，

Wherein, A is the branch road incidence matrices of all described branch roads when running, y _bfor taking branch admittance as the diagonal matrix that diagonal entry is formed, described X is for being the diagonal matrix that diagonal entry is formed with membership, and its expression formula is:

Wherein, l is branch road sum in network, and described membership is: work as x _iwhen=1, branch road runs, and works as x _iwhen=0, branch road disconnects.

Described constraints submodule comprises the first constraints submodule, the second constraints submodule, the 3rd constraints submodule and the 4th constraints submodule; Wherein,

Described first constraints submodule is:

$I_k\≤I_k^{\max },$

I _kfor the real-time current value of a kth tree topology figure, for the lowest high-current value of a kth tree topology figure, wherein, I _kcan be calculated by following formula:

$I_k=\left|\frac{{\stackrel{.}{V}}_{\mathrm{ks}}-{\stackrel{.}{V}}_{\mathrm{kt}}}{z_{\mathrm{kst}}}\right|,$

be respectively the voltage phasor of a kth tree topology figure, z _kstfor this branch impedance value;

Described second constraints submodule is:

V _i ^min≤V _i≤V _i ^max，

Wherein, V _i ^minand V _i ^maxbe respectively minimum amount of voltage that and the maximum voltage value of node i;

Described 3rd constraints submodule is:

SumX=n-n _s-2, wherein, sumX is the summation of X diagonal matrix elements, and n is node total number amount, n _sfor branch road quantity;

Described 4th constraints submodule is:

X _f=0, wherein, f is the numbering of branch road of breaking down.